A response to questions about snow next week

Many of you have heard rumors of snow. Let’s talk about that. We’re over 3 weeks away from the start of meteorological winter, yet next week’s setup is very impressive for this time of year. In my opinion, the real story will be the cold. Most regions along and east of the Rockies will experience temperatures that would be expected during the winter.

Projected temperatures at 7am ET on Nov. 13 2019
Projected temperatures at 7am ET on Nov. 14 2019

Our first frontal passage is moving across the country now. If you check out current U.S. temperatures, you can see the cold front quite nicely. All of the snow talk is about the second cold front moving through early next week. That’s going to bring the real cold.

Basically, a strong mid-to-upper level trough is going to become oriented from southwest to northeast, extending as far south as Texas and Mexico. A strong cold front will be associated with the trough, and a surface low will likely develop to the east of the trough axis. It’s very possible that this surface low will track along the Gulf Coast states, exit off the Southeast coast and skirt parts of the East Coast.

There should be the development of precipitation along and ahead of the cold front. Due to the potency of the air mass moving in behind the cold front, most model guidance shows a transition from a cold rain to snow and sleet on the backside of the precipitation shield. As shown by the European model, you will notice accumulations occurring unusually far to the south. Other models have shown this as well.

Projected snowfall accumulations early next week, a forecast that will likely change significantly between now and then
Projected snowfall accumulations early next week, a forecast that will likely change significantly between now and then

When I’m looking for decent snow accumulations to occur farther south, I like to see a well-developed surface low pressure system. When a trough is oriented from southwest to northeast, the surface low generally remains weak. Thus, any frozen precipitation basically has to occur along a frontal boundary without any well-defined low. It does happen, but a setup like this doesn’t usually produce a big winter storm. Remember when Firsthand Weather busted horribly on a winter storm forecast last year? We expected accumulating snowfall to occur along a strong cold front without a well-developed surface low. We blew the forecast.

I’m a bit more concerned about temperatures dropping rapidly while roads are still wet. Oftentimes, roads are able to dry before temperatures reach freezing, but again, the air mass behind next week’s front is potent. Remember, temperatures will be at levels that we’d typically experience during winter. Some of the model guidance strengthens the surface low off the Southeast coast; thus, I’m not willing to discount accumulations being depicted across parts of North Carolina, Virginia, and northward along the coast just yet.

My hope is that many of you will get to experience a little snow. I suspect that accumulations won’t occur anywhere south of a line that runs from Oklahoma, central Arkansas, Tennessee, and North Carolina. Again, any concerns south of that line would likely be due to black ice, which can be quite dangerous.

I’ll post a more in-depth forecast on the site, if needed. I believe we need to watch everything a couple more days before we put out any detailed forecasts.

Accumulating Snow Likely For South And Southeast!

The chance for snow continues to increase for parts of the South and Southeast early next week. An arctic cold front will move out of the Southern Plains into the South by Monday afternoon with temperatures quickly falling to near or below freezing behind the front. At the same time, an upper-level shortwave will move overhead. This shortwave combined with the vertical profile of the cold front will generate a strong upward motion in the atmosphere to allow precipitation to develop along and behind the cold front. Precipitation immediately behind the front will fall as rain Monday night and quickly transition to wet snow by Tuesday.

The first areas to experience snow will be far eastern Oklahoma, northeast Texas, Arkansas, western Tennessee and northern Louisiana by late Monday night. The rain & snow will move east and southward by early Tuesday morning into central Tennessee and parts of Mississippi (see Fig. 1) before moving further east into parts of Alabama and Georgia later on Tuesday (see Fig. 2). Parts of upstate South Carolina and North Carolina should get in on the rain & snow later in the day on Tuesday.

Fig. 1: Future radar Tuesday morning (please note: this should be used as an estimate–exact placement of precipitation will change)
Fig. 2: Future radar Tuesday afternoon (please note: this should be used as an estimate–exact placement of precipitation will change)

While this is not a setup that climatologically produces major snow events, it increasing in likelihood that accumulations are likely. The event being a few days out makes it extremely difficult to forecast snow accumulations. There are two big negative factors for accumulations. I) Monday (the day before the snow) will be warm across this region, which will lead to warmer ground temperatures, and II) the window for snow is only about a 4-6 hour period. With that said, this does appear to be the best chance so far this season for accumulating snow across the South and Southeast. The snow rates should exceed melting and the best chance for accumulations will across northern & central Mississippi, Tennessee, northern & central Alabama, northern Louisiana and northern Georgia. Guidance is evening indicating some instability, which could lead to convective banding of snow. This could dump heavy snow amounts for isolated locations. It is too difficult to pinpoint where those bands may setup. That is almost a nowcasting scenario. Secondly, areas that see snow pre-dawn on Tuesday will have the best chance to see accumulations and nasty road conditions. Even though it is difficult to forecast snow accumulations this far out, I wanted to provide you with a preliminary snow accumulations map (see Fig. 3). Please note, this will likely change over the next 48-72 hours as we get closer to the event. It is possible the polygons may need to me reduced or expanded, and snow totals may need to be increased or decreased.

Fig. 3: Preliminary snow accumulation map

Please keep checking back for the latest updates!

Southern Snow Next Week! Accumulations Likely

The chance for snow continues to increase for parts of the South and Southeast for early next week. A potent cold front will move out of the Southern Plains into the South by Monday afternoon. Temperatures behind this front will quickly fall to near or below freezing. At the same time, an upper-level shortwave will move overhead. This shortwave combined with the vertical profile of the cold front will generate a strong upward motion in the atmosphere to allow precipitation to develop along and behind the cold front. Precipitation immediately behind the cold front will fall as rain Monday night and quickly transition to wet snow by Tuesday.

The first areas to experience snow will be eastern Oklahoma, northeast Texas, Arkansas, western Tennessee and northern Louisiana Monday night. The rain & snow will move east and southward by early Tuesday morning into central Tennessee and parts of Mississippi (see Fig. 1) before moving further east into parts of Alabama and Georgia later on Tuesday (see Fig. 2). It is possible parts of upstate South Carolina may even see a light rain & snow mix by late Tuesday.

Fig. 1: Future radar Tuesday morning (please note: this should be used as an estimate–exact placement of precipitation will change)
Fig. 2: Future radar Tuesday afternoon (please note: this should be used as an estimate–exact placement of precipitation will change)

While this is not a setup that climatologically produces major snow events, it appears accumulations are possible if not likely. Being a few days out, it is extremely difficult to forecast snowfall amounts. Especially given the warm day before the snow falls. However, the snow rates should exceed melting and the best chance for accumulations will across northern & central Mississippi, Tennessee, northern & central Alabama, northern Louisiana and northern Georgia (see Fig. 3). At this point, it appears some areas may see 1-4″. This will impact travel, especially for areas that see snow fall pre-dawn on Tuesday.

Fig. 3: Preliminary snow outlook

It should also be noted, a weak shortwave will move into the South and Southeast late Saturday into Sunday. Overall, this shortwave should not develop much precipitation but a sprinkle or flurry is possible across northern Mississippi, northern Alabama and northern Georgia during this timeframe. Again, do not expect anything significant. It is likely that most areas will only see an increase in clouds. Late next week also needs to be monitored closely as a strong arctic front moves into the South and Southeast. A strong temperature gradient could allow for a surface low-pressure to develop, which could generate wintry precipitation for the region (more details to come as we get closer).

Major Cold On The Way

A very cold stretch is in store for the Midwest, Great Lakes and Northeast through the end of January into early February (this will impact the Southeast–details discussed later in the article). Temperatures tonight into tomorrow morning will feel like 20 to 40 below zero for parts of the Midwest and Great Lakes (see Fig. 1). This cold will continue into the weekend for these regions and parts of the Northeast but the coldest air will arrive by mid to late next week.

Fig. 1: Feels like temps early tomorrow (Friday) morning

As we head into mid week (the end of January), it appears the polar vortex (I know, you’re tired of hearing this since it is so freely tossed around via media) will drop into the Midwest & Great Lakes (see Fig. 2). This equatorial displacement of the polar vortex will allow temperatures to fall even further than what will be experienced tomorrow (Friday) into the weekend. Temperatures by mid next week will be 30 to 50 degrees below average (see Fig. 3). High temperatures for parts of the Northeast, Midwest and Great Lakes will not get above 0 from Wednesday through at least Friday and likely be 5 to 15 degrees below zero for highs. It is possible feels like temperatures will be close to 60 degrees below zero.

Fig. 2: Polar vortex over the Great Lakes by mid next week
Fig. 3: 850mb temp anomalies by mid next week

So why is this cold air moving into the lower-48? The answer is due to a stratospheric warming event that occurred a few weeks back. When a quick stratospheric warmup occurs, it can allow the polar vortex to weaken and thus get displaced from the North Pole; sometimes that displacement is farther south towards the North American continent. When the displacement is over the North American continent (which is this case this time), very frigid air can engulf parts of the lower-48. This will be the case next week and possible as we head into February due to the weakened state of the polar vortex.

It is not only locations of higher latitude that will get in on the cold weather. Parts of the Southeast will be very frigid too by the end of next week (see Fig. 4). Thursday and Friday may of next week may feature high temperatures below freezing for parts of Tennessee, Georgia, North Carolina, Alabama, Mississippi and South Carolina with lows in the teens (or possibly single digits for some locations).

Fig. 4: 850mb temp anomalies by late next week

It should be noted, temperatures of this magnitude are dangerous. Actions must be taken to ensure your pets are protected. DO NOT LEAVE YOUR PETS OUTSIDE if cold weather is in the forecast for your area. If you have elderly neighbors, make sure they are okay. Protect the plumbing in and around your house and be VERY CAUTIOUS with space heaters.

Winter Weather to impact the East Coast

Winter Weather Advisories have been put into effect from Louisiana through parts of Northern Georgia.   This system is going to head toward the coast and move up the Eastern Seaboard with minor to moderate impacts.

Matt and Chris already have good coverage for the forecast for the Southern Plains and the Southeast, so my focus will be from the Delmarva Peninsula northward into New England.   A cold front associated with a system that moved up into Canada, has pushed well into the Gulf and off the east coast, spanning from near Greenland back to Mexico.  The cold air is well established with snow as far south as the Texas and Mexico border and advisories to nearly the Gulf Coast.

One of the challenges with this system will be the usual early season marine influence.   Sea surface temperatures are still warm and any easterly winds will impact surface temperatures over the land.  This will be a major impact along the coast down in Virginia and for Cape Cod as well as the islands.  Coastal areas should expect to see a heavier wetter snow once the snow starts to fall.  This set up may also trigger a few ocean effect bands, which could make for small areas of higher snow totals right next to areas of lower totals.

The NAM model is being for more aggressive with snowfall accumulations across the region than other modelling, though this is common for the NAM.   The expected snowfall accumulations occur for most locations later on Saturday into Saturday night.  The GFS shows a far lower area of accumulation as well as lower overall totals.

Figure 1: NAM model snowfall accumulation forecast through Sunday afternoon. Source: Tropical Tidbits

winter

Figure 2: GFS model snowfall accumulation forecast through Sunday afternoon. Source: Tropical Tidbits

Despite the differences, both models show plowable snows into the I-95 corridor with some higher snowfall total further east where the rain/mix doesn’t hold totals down.   I’ll be doing some follow ups on this as the track and actual conditions get closer.   There is another chance for a storm early next week that we’ll also be keeping an eye on as cold and windy conditions are expected to take hold in the Eastern United States, but we’ll get through this first storm first and focus on the longer term risks as they get closer.

 

Rob

 

 

 

 

Lake Effect Snow Machine slams into high gear

Cold air has returned to many areas in the East as a cold front advances off the Coast, as previously mentioned in Chris’s article.   This air, along with strong northwesterly winds, will combine with the unfrozen lakes to produce large quantities  of lake effect snow through this weekend.     I expect that the snow will continue to pile up through Sunday and beyond with some areas seeing several feet of snow.  New York, Pennsylvania, Vermont, Ohio, and Michigan will be impacted by this event.

lake effect

Above photos courtesy of NWS Buffalo and NWS Cleveland

 

Lake Effect Snow Warnings and Watches

Lake Effect Snow Warnings are in effect for Southern Erie, Wyoming, Cattaraugus and Chautauqua counties in Western New York.  The warning is in effect until 7:00 p.m. on January 29.  Storm total snowfall of 2 feet or more will be possible in the most persistent lake snows.

Lake Effect Snow Warnings are in effect for Jefferson, Oswego and Lewis counties in North Central New York.  The warning is in effect until 7:00 p.m. on January 29.  Storm total snowfall of 3 feet or more will be possible in the most persistent lake snows.

Lake Effect Snow Watches are in effect for Northern Erie and Genesee counties. The watch is in effect from morning through late night on Saturday January 28th.  Storm total snowfall accumulations of 5 to 10 inches are possible in the most persistent lake snows.

A Lake Effect Snow Watch is in effect for Allegany County through the evening on Sunday January 29th.  Storm total snowfall accumulations of 10 to 20 inches are possible in the most persistent lake snows.

No advisories are issued in Michigan at this time but they will likely be issued later on.

Travel Hazards

Interstates 75, 80 , 81, and 90 should expect to see heavy precipitation at times from now through the weekend.  Visibility in these areas can be 10 miles one minute and then suddenly drop to white out conditions as you enter the snow bands.  Travel in this area should be taken with a maximum of preparations and should be avoided if at all possible.  We have all seen the images of backed up traffic where several inches of snow piles up very quickly on roadways that can’t be plowed with the cars in the way.

 

Rob

Significant storms impact both coasts

Active Pattern leads to a significant storms early next week:

Significant Storms are set to take place in an active pattern across the United States will bring severe weather to the Gulf Coast and Widespread rain with heavy mountain snow to the West.  These frequent West Coast fronts will eventually lead to a strong system developing in the south and moving off the coast of the Northeast.

Significant Storms

Showers and thunderstorms are expected to be widespread tonight in association with an upper level disturbance from portions of the Gulf Coast and Southeast to the Ohio valley and portions of the Great Lakes.   An evolving cluster of thunderstorms bring the risk for potentially damaging wind gusts, and perhaps a tornado or two, across southeastern Alabama and portions of the western Florida Panhandle by late this evening.  An increasingly organized convective system is forecast across the region and extends the Severe risk into West Central and Southwestern Georgia overnight, but this system will continue to be just disorganized enough to only cause a few severe storms.  Issuance of a watch is not likely at this time.  Rain will spread northeast on Friday across portions of the Mid-Atlantic and lower Great Lakes. Farther south, another round of showers and thunderstorms is expected to develop during the afternoon and evening along the Gulf Coast, some of which could once again become severe across the lower Mississippi Valley and adjacent Gulf coastal areas.  Primary convective development may occur in response to strengthening low-level warm advection on the leading edge of the deeper/more favorable low-level moisture return.  This is expected across parts of the northwestern Gulf of Mexico/upper Texas and Louisiana coastal areas Friday evening, northeastward through portions of southern Louisiana and central Mississippi Friday night, primarily as a risk for severe hail.  By late Friday night, forcing for ascent may become strong enough southward toward southeast Louisiana/Mississippi/Alabama coastal areas, to overcome inhibition and support increasing convective development.  In the presence of increasing boundary layer based instability, the risk for supercells with potential for tornadoes, in addition to large hail and damaging winds, may increase by or shortly after Saturday morning.

Meanwhile, A Pacific frontal system will move onshore along the West coast tonight, bringing widespread rain and mountain snow.  As the system moves inland, snow will spread into portions of the Great Basin and Four Corners region on Friday as this system becomes one of the significant storms expected to impact the states.  Winter Storm Warnings are in effect and some of the higher elevations could see as much as 4 feet of snow fall as this system passes through.    For lower elevations, rain and wind will be the issue with many counties under High Wind Warnings.    Some areas in this region have already seen as much as 6 inches of rain over the last few days and flooding is an issue.   Scattered convective development appears possible during the day Friday, in the presence of lower/mid tropospheric warm advection. The convective layer may be sufficient for low topped supercells, with a risk for strong surface gusts and perhaps a tornado.  The severe threat dies out overnight Friday but heavy snow will be possible through Saturday morning for the mountains in California as well as areas from the Mogollon Rim to the central and southern Rockies.  By late Saturday into Saturday night, rain and mountain snow will begin to increase once again from central California northward along the coast as another frontal system approaches from the Northwest.  Rain and snow will start first in Washington and Oregon before shifting south across California and the Rockies.   Winter Storm Watches are already beginning to go into effect for this system with the forecast calling for an additional 1 to 3 feet in the higher elevations.

 

On Saturday, widespread showers and thunderstorms are once again expected from the Gulf Coast and lower Mississippi valley to the Southeast along and ahead of a developing warm front.  Some storms could become severe by Saturday night and Sunday morning as the trough that’s currently moving onto the west coast shifts east across the Southern Plains by Saturday evening.  Any storms that form here will do so in an environment with steep midlevel lapse rates, moderate buoyancy, and sufficient deep-layer shear for supercells capable of producing large hail (potentially some very large) and damaging winds.  The stronger low-level wind profiles are expected farther east and overnight in association with a lead speed max progressing inland from the Gulf.  Enhancement to low-level shear from south and southeast AL into the FL Panhandle and southwest GA will favor supercells with damaging winds and potentially some tornado risk, depending on the details on the low-level shear and near-ground lapse rates inland.  The Storm Prediction Center has given this area a slight risk at this time but I expect that this will increase as the forecast period gets closer.

Model guidance continues to show a fair amount of uncertainty with the significant storms at the end of this weekend.   The system will be lifting from the Lower Mississippi Valley to the Northeast early next week and could potentially become a significant east coast storm, bringing severe weather to the Southeast and heavy precipitation through New England as the next system moves on shore from the pacific.   The timing and strength of the significant storms has below average confidence at this time, but that will improve as we get a better look at the storm systems involved as they move over land.  There is likely to be a large number of people who will see rain or snow to start next week.

 

Rob

 

Blizzard Warning, Storm targets East Coast

A Blizzard Warning is in effect for Virginia and Massachusetts as a major winter storm takes shape in the southeastern United States.

Blizzard Warning

The rain/snow line continues to slowly collapse over the Carolinas as surface temperatures begin to approach freezing in places like Fayetteville, Goldsboro, Greenville and Elizabeth City at this hour, which is 4 AM EST. Heavy and steady snow is falling across Virginia with the worst expected near the mouth of the Chesapeake Bay, where strong winds and heavy snow will cause blizzard conditions, prompting the issuance of a Blizzard Warning.

 

Blizzard Warning for Virginia

As the storm moves up and along the coast, many coastal locations will slowly get in on the snowfall, but the most snow is expected along the coastline near Norfolk, Hampton Roads, Virginia Beach and Chesapeake Virginia, where the Blizzard Warning is in place until 10 PM Saturday night . Blizzard conditions will be found in this area where 6-12 inches of snow will fall. Winds will be sustained at 20-30 mph with gusts to 45 mph reducing visibilities with blowing and drifting snow. Most counties in Virginia remain under a Winter Storm Warning and will see several inches of snow as forecast by Matt and Chris in earlier articles, maps, and posts to the Facebook page.

New Jersey and the Delmarva

The storm will move off the Mid-Atlantic coast late tonight into Saturday morning. While the major metro areas around New York City, Newark, Trenton, Philadelphia down to Baltimore and D.C will be spared major snowfalls, regions to those cities Southeast will see snow overspread the area from the South late tonight into the early morning hours of Saturday. The snow will be heavy at times during the morning and early afternoon and will taper off from west to east during the late afternoon and early evening.

Warnings and Advisories

A Winter Storm Warning remains in effect from 3 am to 6 PM EST Saturday for Atlantic, Cape May, Ocean, Cumberland and Southeastern Burlington County in New Jersey, Kent and Sussex County in Delaware and Caroline, Dorchester, Worcester, Somerset, St. Mary’s, Talbot, and Wicomico County in Maryland for 4-7 inches of snow. Winds will be out of the northwest at 5-10 mph increasing to 15-20 mph. Winds gusts into the 30 mph range can be expected, especially along the coast. Visibility could drop to less than 1/2 mile. While it’s possible that blizzard conditions could exist for a short time period in this area, a Blizzard Warning will not be issued.

A Winter Weather Advisory is in effect from Delaware, Eastern Chester, Eastern Montgomery, Lower Bucks and Philadelphia County in Pennsylvania, New Castle County in Delaware, Camden, Monmouth, Gloucester, Northwestern Burlington, and Salem County in New Jersey, Anne Arundel, Calvert, Cecil, Central and Southeastern Howard, Central and Southeastern Montgomery, Charles, Kent, Prince George’s, Queen Anne’s, Southeast Harford and Southern Baltimore County in Maryland as well as Washington D.C. 1-3 inches of snow is generally expected in this area with winds of 10-15 mph gusting to 25 mph. Snow will start from South to North tonight into Saturday morning and end West to East Saturday afternoon into the overnight hours.

 

New England and Long Island

A major winter storm will strike Southeastern New England with blizzard to near blizzard conditions likely and significant snow accumulations across much of Eastern New England. Snowfall Friday Morning brought a general accumulation of 3-5 inches across Southeast Massachusetts and South-Central Rhode Island with isolated amounts up to 7 inches on parts of Cape Cod and the Islands where snowfall rates briefly reached 1- inches per hour while lighter snowfall amounts occurred to the north and west of Boston.

Snow should overspread the region from Southwest to Northeast during the late morning hours on Saturday. The heaviest snow, and likely blizzard conditions will be between 4 PM and 10 PM, with the snow tapering off from there during the overnight hours.

Warnings and Advisories

A Blizzard Warning is in effect from 7 AM Saturday to 4 AM Sunday for Cape Cod and the Islands, Coastal Plymouth County for 12 to 18 inches of snow. Strong Northeasterly winds of 20-30 miles per hour with gusts to 45 mph will cause blowing and drifting snow to combine with the heavy snowfall to reduce visibilities to less than 1/4 mile at times.

A Winter Storm Warning is in effect from 7 AM Saturday until 4 AM Sunday for Bristol County and Western and Southern Plymouth County Massachusetts for 12-16 inches of snow with isolated higher amounts and considerable blowing and drifting snow with a period of near blizzard conditions as wind gusts get into the 40 MPH range.

A Winter Storm Warning is in effect from 7 AM Saturday to 1 AM Sunday for all of Rhode Island and Essex, Suffolk, Central and Southeast Middlesex, Norfolk Southern Worcester and Northern Bristol County Massachusetts, New London, Tolland, Windham, New Haven, and Middlesex County in Connecticut and Eastern Suffolk County in New York for 4-8 inches of snow and isolated higher amounts possible along Northeast coastal Massachusetts and Southern Rhode Island. Wind gusts to 35 MPH may result in considerable blowing and drifting snow. Blizzard conditions may exist for a short time period along the coast, but they will not last long enough to cause the issuance of a Blizzard Warning in these counties.

A Winter Weather Advisory is in effect from 7 AM to 10 PM Saturday for Northwest Middlesex, Northern Worcester Franklin Hampshire and Hampden Counties of Massachusetts, Fairfield, Litchfield and Hartford Counties in Connecticut and Western Suffolk county in New York for 3-6 inches of snow.

Areas outside of the advisory will likely see a coating to 3 inches of snow with the 3inches amounts closest to the advisory area.

Lake Effect Snow Warning

A Lake effect snow warning remains in effect until 1 PM EST Sunday for Oswego and Southern Lewis Counties. the highest amounts will near and south of the Tug Hill.

Snow should accumulate 4 to 8 inches during the course of the day on Saturday, and then add another 5 to 10 inches Saturday night with another 2 to 4 inches before the band tapers off on Sunday. This totals too 11 to 22 inches of snow from now until early Sunday afternoon.

For the Jamestown area off Lake Erie, the Lake Effect snow will take a break on Saturday, but will be back later on Saturday night into Sunday.

Robert Millette

Firsthand Weather

Speaking of weather warnings, my friend recently had a serious slip on ice and did her some damage. She decided to sue. She looked into legal representation similar to Cambridge slip and fall lawyer, to begin with. But in the end, she decided to go with different legal aid and that lawyer helped her out so much.

2 storm chances for East Coast

The Southern Storm is the big story with winter weather expected to impact from Texas to the Eastern Seaboard, leaving the first storm expected to form off the coast of the Carolina’s pretty much no attention attention.

 

This weak system is expected to slide up the coast and bring some rain to Eastern North Carolina with light snow from areas of Nebraska into Kentucky to Delaware and New Jersey ahead of the Southern Storm.  Matt has posted a handy map of the Winter Weather Advisories that are currently in place as this weak system moves across the country toward the coast.   This system will combine with the low shown above and slowly intensify as it moves to the Southeast of New England.  This system will bring snow into Southeastern New England with light accumulations during the early morning hours of Friday into Friday afternoon.    Early activity will likely be in the form of snow showers which may limit to coverage area of overall snowfall but the biggest problem to accumulating snow will be the warmth of the ground.   Any snow that does manage to stick will have a difficult time remaining in place for long, with the one thing that may save some areas from an instant melt being the cold temperatures on the way following this system.

Southern Storm

For the main event, which have been covered well by Chris and Matt for the Southern areas that’s will be impacted, the Southern storm looks like it’ll be wide right for many of our readers.  As seen in the previous articles, the system forms in the South and slides off the coast of the Carolina’s, leaving the heavier snow totals expected for that region.  the uncertainty in the speed and exact track of this system is causing some forecast issues, but aside from some lake effect snows  caused by the general flow pattern in the Great Lakes region, this second system looks to leave readers across most of Kentucky, West Virginia, Western and Central Pennsylvania back towards Ohio high and dry.

Southern Storm

The above model data is for 1 PM Saturday.   It shows the storm after it has left Georgia and areas further west and does not indicate that it will not snow there at all.  Just that it will not be snowing there at this particular point in time.

Watching the strength and track

The key question to the track of this system will be the strength of the lows and the energy brought into the pattern.  A strong set up will include more of the Eastern portions of the U.S while a weaker pattern will deprive even New England of any snowfall.  Despite the impressive moisture associated with this system, guidance is now really strengthening these lows very much.   For anyone along the Mid-Atlantic and Northeast, please read the articles Matt and Chris put out about the south to stay informed about this system.   The information they have will be invaluable for track this system up the coast over time.   I’ll be around to keep you up to dat on all the latest for this system and its impacts for this region.   So keep an eye on both facebook and the website for further details.

 

Robert Millette

Firsthand Weather

Forecast and Severe Outlook: Wednesday, May 11th

Additional severe weather is in the forecast as the last several days have brought 67 tornadoes from Colorado to Kentucky.  Strong low pressure moving into Canada will continue to move a strong warm front North ahead of a weaker cold front.   This clash of frontal boundaries is responsible for the weather the Plains and river valleys have been dealing with.

The current Surface Analysis

Surface map us

Today’s National Forecast

Weather Forecast map

The main weather feature across the nation will be a strong low pressure system over the north-central U.S. that will have a trailing cold front extending southward to Texas and the Desert Southwest. An occluded surface low over North Dakota will slowly lift northeastward to southern Canada, with rainy weather over eastern Montana and western North Dakota for the first half of Wednesday. Farther to the south, another surface low along the trailing cold front will also produce widespread showers and thunderstorms extending from Texas to the Ohio Valley. Some of these storms could be severe at times, and also produce localized flash flooding.

Temperatures are expected to be below normal across much of the Intermountain West with an upper level trough in place, and also for the Northeast U.S. which will be under the influence of a Canadian surface high. It will continue to be warm and humid south of a stationary frontal boundary, which will extend from the Ohio Valley eastward to the Mid-Atlantic coast. Highs in the 80s to near 90 along with noticeable humidity will be commonplace across the Deep South and the Southeast states.

West of the Rocky Mountains, a quiet weather pattern should prevail through the end of the week with no Pacific storm systems imminent. Inland temperatures should slowly return closer to average after the recent cool weather.

Current Severe Weather Outlook

Fire Weather Update

Fire Weather

No critical Fire areas to report.

Severe Weather Analysis

Summary

Scattered severe storms are forecast from parts of North Texas into Oklahoma and the Missouri and Mississippi River Valleys. Large hail and damaging winds will be the main concern by late in the day but a brief tornado or 2 are possible for this region.  For the Ohio Valley into the Mid-Atlantic, isolated severe hail or wind is possible during the day.

Severe Outlook

Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 47,289 2,762,058 Norman, OK…Wichita Falls, TX…Lawton, OK…Broken Arrow, OK…Muskogee, OK…
SLIGHT 218,024 19,885,612 Dallas, TX…Fort Worth, TX…Oklahoma City, OK…Kansas City, MO…Tulsa, OK…
MARGINAL 378,142 52,006,921 Chicago, IL…Indianapolis, IN…Columbus, OH…Charlotte, NC…Milwaukee, WI…

Analysis

Low pressure will move across Iowa during the day today and bring a warm front across Missouri into Central Illinois and across the remainder of the Ohio Valley. A very moist air mass exists behind this front supporting scattered storms during the day from Iowa into the Ohio Valley.  Warm advection will allow for development of storms across Virginia and North Carolina under the influence of the disturbance currently causing thunderstorms in Kentucky.

Moderate to strong mid-level flow will spread into the Oklahoma and Far Northern Texas area as a weak cold front extends from Missouri down into Northwestern Texas by late this afternoon. A very warm and moist air mass is already in place though current storms in the area will play a pivotal role in destabilization during the day.  Strong instability will lead to intense clusters of thunderstorms with the primary threats of wind and large hail across the enhanced risk area.  A couple of tornadoes cannot be ruled out for this region.

Substantial moisture and instability is currently developing over Eastern Kansas and Western Missouri causing cluster of thunderstorms to form during the overnight hours. This activity is expected to continue during the morning hours with a threat of large hail.  Further development of stronger storms during the early afternoon will present a risk of damaging winds as a mesoscale convective system develops.

Dewpoints in the 60s across Iowa are forecast to result in a small corridor of supercell activity. Some heating is expected during the day as shear profiles are locally enhanced by the presence of the low pressure system.  Hail will be the primary threat with these storms but there is a risk of tornadoes later in the afternoon.

This Week’s Flood Risk

Flood Risk

Yesterday’s Storm Reports

storm reports 2

Robert Millette

Staff Meteorologist

Firsthand Weather