Chilly and Wet Pattern

A transition to a more amplified pattern will occur, which will usher in big changes for the eastern United States–including the Southern Plains next week. The combination of positive PNA (see Figure 1), negative AO (see Figure 2), and negative NAO (see Figure 3) will be conducive for a strong north Pacific ridge (into Alaska) and high-latitude blocking (see Figure 4). This synoptic setup, along with a well established snow pack (see Figure 5), would allow for a deep trough to setup for areas east of the Rockies.

Figure 1: PNA Forecast

Figure 2: AO Forecast

Figure 3: NAO Forecast

Figure 4: 500mb Height Anomaly Map: GEFS(Next Wednesday)

Figure 5: Current snow and ice cover

For the Southern Plains, a cold front looks to advance into the region early next week. The guidance is struggling on the exact timing, which is expected during an amplified pattern, but a Monday or Tuesday time frame looks likely–and temperatures will stay well below average for much of the upcoming week (see Figure 6). This will generate showers and thunderstorms for this region (mainly along and east of I-35), which is much needed–many areas are slipping into a drought. It is possible a few post-frontal showers may occur immediately behind the cold front.

Figure 6: Surface Temperature Anomaly Map: GEFS (December 5th-December 10th)

Eyes then turn to the west. Guidance is indicating a disturbance or two may ‘ride’ over the ridge out west and down into the southern Rockies. Depending on the timing and strength of the disturbance(s), it is possible light precipitation may develop during Wednesday and/or Thursday time frame for Texas and Oklahoma. Again, the timing and strength of the disturbance(s) is questionable, and the amount of moisture is unknown, but we will need to keep a close eye on this setup since anomalously cool air will be in place. It is not out of the question that wintry precipitation chances may be possible. At this time, the greatest chance would be for western Oklahoma and western Texas.

The wintry precipitation chances are NOT set in stone, but I am keeping a close eye on next week. The guidance should become more certain with the evolution of the synoptic pattern by this weekend, and thus a more detailed forecast will be provided then once the finer details are known. The cold air will advance eastward into the Northeast, Mid-Atlantic, and Southeast by mid-next-week. This cold air will remain in place for this region through the weekend. Matthew will have a detailed article out tomorrow on the impacts for this region.

2017 Thanksgiving Travel Conditions

It is that time of the year when millions travel to enjoy time with their families and friends to enjoy Thanksgiving. It it is estimated that 50 million people will travel for Thanksgiving this year. So how are the travel conditions for your area and where you’re traveling to (see map below regional discussion)?

Southeast:
Travel conditions overall will be good in this region. Parts of Florida and the coastal areas of Georgia and South Carolina may see a few showers or storms, so conditions may be slightly less favorable in this area.

South-central:
Travel conditions will be good in this region.

Southwest:
Travel conditions will be good in this region.

Northeast:
Travel conditions will be good in this region outside of western areas near the Great Lakes. In the Great Lakes region, lake snows are possible, which will cause poor travel conditions.

North-central:
Travel conditions will be impacted by snow in this region.

Northwest:
Travel conditions will be heavily impacted by heavy snow in the higher terrain and heavy rainfall in the valleys.


Firsthand Weather’s Travel Forecast

2017-2018 Winter Outlook (Snow Maps, National & Regional Maps Included)

Introduction:

It is that time of the year. The days are getting shorter; the temperatures are getting cooler; and, many have already seen their first freeze or snow of the season. After last winter’s lackluster performance, for most regions, many are wondering what the 2017-2018 winter season will bring. Seasonal forecasting is difficult, and an inexact science, in which many meteorologists have varying methods to generate a seasonal forecast. There are a variety of current or predicted teleconnections and features around the globe that can aid in giving a snapshot of what this winter may feature for the U.S. A few of these are: ENSO, QBO, snow and ice cover, NAO, AO, PDO, TNH, and solar activity.

I will get into a few of these later in the article, but first, here is the 2017-2018 Winter Outlook and Snow Outlook. You will notice I have a National map and two Regional maps (Southern Plains and Southeast).

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2017-2018 Winter Outlook

2017-2018 Snow Outlook

2017-2018 Winter Outlook (Southern Plains)

2017-2018 Snow Outlook (Southern Plains)

2017-2018 Winter Outlook (Southeast)

2017-2018 Snow Outlook (Southeast)

Regional Discussions For NATIONAL MAP (Image 1):

A (El Paso, TX; Albuquerque, NM; Tucson, AZ; Phoenix, AZ; Las Vegas, NV): This region will feature bland winter conditions. Temperatures and precipitation will be near average. The best chance for rain and snow in this area will come with cutoff lows that can develop southwest of California and move across the Southwest or through northern Mexico into southwestern Texas. It is possible upslope freezing drizzle may occur at times in west Texas.

B (Houston, TX; New Orleans, LA; Biloxi, MS; Montgomery, AL; Augusta, GA; Charleston, SC): This region will be characterized by temperatures above average and precipitation near to slightly below average. Do not let the above average temperatures fool you, though. Temperatures will swing from warm to cold frequently. During these temperature swings, it is possible that severe weather will occur. It is possible the northern parts of this region will see one significant winter weather event.

C (Dallas, TX; Shreveport, LA; Jackson, MS; Birmingham, AL; Huntsville, AL; Atlanta, GA; Chattanooga, TN; Knoxville, TN; Ashville, NC; Washington D.C.): This region will be characterized by temperatures near normal and a very active storm track. Temperatures will see great variance between warm to cold, and thunderstorms possibly followed by sleet and wet snow. Western parts of this region have a higher percentage to see an ice storm, and at least two winter storms are possible in this area.

D (Lexington, KY; Pittsburgh, PA; Philadelphia, PA; New York, NY; Boston, MA; Portland, ME): This region will be characterized by temperatures near to slightly above average. Don’t let this fool you though. Snow will be above average and occur frequently in this region. 1-2 potent Nor’easters look possible for eastern parts of this region.

E (Chicago, IL; Milwaukee, WI; Minneapolis, MN; Rapid City, SD, Bismarck, ND; Billings, MT; Salt Lake City, UT; Boise, ID; Seattle, WA): This region will be characterized by cold temperatures and frequent snowstorms. The coldest temperatures will occur in the Northern Plains with the wettest conditions occurring in the Northwest.

F (Detroit, MI; Marquette, MI; Cleveland, OH; Erie, PA; Buffalo, NY): This region will be characterized by heavy lake enhanced snow and temperatures below average. Lake temperatures are anomalously warm, which will aid in heavy snowfall once cold airmasses move in from the northwest.

G (Amarillo, TX; Oklahoma City, OK, Tulsa, OK, Wichita, KS; Kansas City; St. Louis, MO; Indianapolis, IN): This region will be extremely active, and likely be the region that will see the most frequent mid-latitude storms. Temperatures will be slightly below average and snowfall will be above average.

H (Portland, OR; San Francisco, CA; Los Angeles, CA: Reno, NV; Colorado Springs, CO): This region will be characterized by its unsettled conditions. Precipitation will be above average and temperatures near to just below normal. The higher terrain will see above average snowfall.

Discussion/Method:

La Niña was finally realized over the past few days. Below-average sea surface temperatures (SSTs) have been observed across much of the central and eastern equatorial Pacific, and the Niño indices are just below -0.5° C in the Niño-3.4 region and the Niño-3 region. I know this concerns winter-temperature lovers across the South because La Niñas can generate upper-level ridging across the Southeast (which brings anomalously warm temperatures), but please note, there are several more variables that play into a seasonal outlook outside of ENSO. The location of anomalously cool SSTs in the ENSO regions and strength of La Niña are important and plays a large factor in precipitation and temperature patterns in the U.S. (although it is not the only indicator of future atmospheric patterns).

There are two important factors to evaluate with the current La Niña. I) The current and and forecasted intensity of La Niña, and II) the ENSO regions with the most anomalously cool SSTs. The current La Niña is weak and should remain weak through the winter. The dynamical and statistical models for SSTs in the Nino 3.4 region shows this to be the case through the winter months (DJF). The current La Niña is more of an eastern Pacific based event. The eastern based La Niña is evident when looking at the current sea surface temperature anomalies (SSTAs). The SSTAs are very cool across the equatorial parts of the eastern Pacific down through just off the West Coast of South America.

This type of La Niña, when weak, can aid in more volatile weather for southern parts of the mid-latitudes by allowing the Polar Jet to not stay fixed over higher latitudes throughout the winter season–especially when paired with specific phases of other teleconnections, which is discussed below. This year’s La Niña will feature frequent, but not prolonged, periods between anomalously cold and warm conditions for areas closer to the Gulf. Overall, the temperatures will average out just above average, but several bouts of cold are likely throughout parts of the winter. The weak La Niña should aid in enhanced storminess through the Arklatex, Tennessee Valley, and Ohio Valley due to surface lows digging into the mean trough axis.

Current SST Anomalies (Pacific)

ENSO Predictions Plume

The North Atlantic Oscillation (NAO), the Artic Oscillation (AO), are also crucial teleconnections to take into consideration during seasonal forecasting–especially during the cool months. The NAO, which can be hard to forecast outward more than a few weeks in advance, has large implications on winter seasonal outlooks—especially for areas east of the Rocky Mountains. Currently, the NAO appears to take a negative phase dip for the second half of November–and I believe a more neutral to slightly negative phase is likely for parts of the winter. This is due to the SSTs across the northwestern Atlantic. SSTs are anomalously warm in this region, which again, increases the likelihood of the NAO dipping to a negative phase, and increases the chance of Mid-Atlantic/New England systems tapping into the warm/moist air leading to intensification. The positive phase of NAO tends to bring warm temperatures to eastern parts of the U.S. while the negative phase of NAO tends to bring cool temperatures to eastern parts of the U.S.

Current SSTAs (NW Atlantic)

The AO has been trending towards negative values in mid-to-late November and should remain in this phase during parts of the winter–similar to the NAO. The negative phase of AO can usher in chilly air into eastern and southern parts of the U.S. This is because the circulation around the North Pole becomes weak, and chilly air can more readily ooze southward. When these two teleconnections dip to negative values, the atmosphere will eventually respond, and very active weather (likely winter storms) will establish across parts of the South and the Mid-Atlantic/New England.

The Pacific Decadal Oscillation (PDO) is important to analyze, too. The PDO has two phases (negative and positive) like the aforementioned ENSO, NAO, and AO. What is unique about the PDO is that the positive and negative phases can last 20-30 years–this is much longer than your ENSO cycles that last half a year or up to almost two years. When the PDO is positive, higher heights develop over Alaska and the northwestern Pacific, which can dislodge cold air over Canada and usher it southward into central and eastern parts of the U.S. The PDO has been positive for a while, but the values have recently dropped from moderately positive to just slightly positive values. The positive phase of the PDO can cause lower heights across the eastern U.S, which equivocates to unsettled weather for this region in the U.S.

Negative AO Pattern

Negative NAO Pattern

Positive PDO Pattern

Another important factor to take into consideration is the snowcover across Siberia and other parts of the Eurasian continent, snowcover across western and central Canada, and the Arctic sea ice extent. The snowcover is well above average and much more impressive this year compared to last year. Very cold air has already begun to establish itself across Siberia. This is promising for those who love cold because the above average snowcover will allow cold airmasses to become well established over this region and move equatorially at times during the winter. This will extend the below average temperatures further south and east outside of the Pacific NW in the U.S. due to the possibility that the polar vortex will break down later in the winter. This would usher in cold air into the U.S., especially northern and eastern regions, according to recent research.

Current Snow and Ice Cover

Taking into consideration some of the aforementioned teleconnections and global features, I picked a few analog years to try to get a good snapshot of what this winter may feature. (Please note, no two years exactly parallel one another.) I chose weak La Niña years to generate temperature and precipitation anomaly composites to help form the framework of the winter outlook. This is what the analog years chosen showed:

Temperature Anomalies

Precipitation Anomalies

2017-2018 Winter Outlook and Snow Outlook Conclusion:

So, to wrap it all up, I believe the 2017-2018 winter will feature great temperature variance across the Southern Plains, South, and Mid Atlantic. Snowfall will be above average in the Mid-Atlantic and for the rest of the Northeast, while the northern parts of the South and the Southern Plains will see a few winter storm threats (including ice). The Northwest, Northern Plains, and Great Lakes will see cold temperatures and above average snowfall. The immediate Gulf Coast and parts of the Southwest will see precipitation near normal and warm temperatures, with a severe thunderstorm threat at times for the Gulf Coast regions.

Bonus: here is MATTHEW’S Winter Outlook.

2017-18 Winter Outlook

Introduction and Overview:

The last two winters were blowtorches. There’s really no better way to put it. The 2015-16 winter was anomalously warm across most of the United States, which was driven by a record-breaking El Nino episode. By that following spring, El Nino had begun to fade as the waters along the central and eastern equatorial Pacific began to cool, and as we approached the 2016-17 winter, sea surface temperature anomalies across that region in the Pacific favored weak La Nina conditions. But, that winter was also very warm from parts of the Southwest and Great Plains to the East Coast! We once again find ourselves in weak La Nina conditions; however, I’m going to explain why it appears that this winter will, at the least, be a bit more exciting across some regions compared to last winter.

This year’s winter forecast is broken down into 11 regions. I encourage everyone to read this forecast in its entirety all the way down to the region-by-region breakdown. Once reaching that section in this forecast, find the number on the map that represents your location, and skip to your (mostly brief) regional discussion. This year’s outlook is a bit more brief compared to previous ones. If you would like to receive more discussion-based, detailed forecasts throughout this winter, I encourage you to signup to receive our newsletter, which will be sent once a week beginning later this winter.

Current State of La Nina (the only semi-technical part of this forecast):

As mentioned above, La Nina conditions are back for a second winter in a row; however, this La Nina is different. But if you were to compare the sea surface temperature anomalies (SSTAs) to last year’s anomalies across the Nino 3.4 region over August, September, and October, you might convince yourself that there isn’t much of a difference. If anything, the SSTAs were slightly warmer over that time period this year. That’s why it’s extraordinarily important to determine how those anomalies are spatially distributed across the central and eastern equatorial Pacific. Notice in Figure 1a how the cooler anomalies are strongest in the eastern equatorial Pacific this year and extend along the Peruvian coast. That’s the complete opposite to what was occurring this time last year in that region (Figure 1b) when those anomalies were actually above average, and the cooler anomalies were more concentrated over the central Pacific. This distinction alone could result in the atmosphere responding completely differently than what occurred last winter.

Sea surface temperature anomalies on nov 2017
Figure 1a: Sea surface temperature anomalies across the central and eastern equatorial Pacific on November 11, 2017

Sea surface temperature anomalies on nov 2016
Figure 1b: Sea surface temperature anomalies across the central and eastern equatorial Pacific on November 11, 2016 (this time last year)

While the above paragraph focuses entirely on the oceanic component of La Nina, it’s extremely important to not ignore the atmospheric component of this phenomenon, which could ultimately have an influence on our overall pattern in the United States this winter. In other words, below-average sea surface temperatures in the central and eastern equatorial Pacific are not as important of a consideration if the atmosphere isn’t responding to these anomalies. The recent Atlantic hurricane season can be used as sort of a proxy to measuring how well the atmosphere is responding. While there is a plethora of other factors to consider, vertical wind shear is generally quite low across the Atlantic when there has been an atmospheric response to developing La Nina conditions. Oftentimes, the amount of vertical wind shear across the Atlantic can be the difference between an active hurricane season and one that’s generally benign. Of course, we all know that this year’s hurricane season in the Atlantic was hyperactive, which likely signals that La Nina was playing a role.

Despite model guidance indicating a relatively weak La Nina event throughout the winter, there are other reasons to come to the conclusion that this event is becoming decently established. Last month, the Madden-Julian Oscillation (MJO) went through an active period. This is a phenomenon that can induce variability (changes) in precipitation, cloud cover, wind direction, etc. in the tropics and even outside of the tropics on a week to week basis. Research has shown that the MJO may play a role in triggering the onset of an El Nino event, and given that La Nina is the opposite of El Nino, the eastward propagation of the enhanced convective phase of the MJO through the central and eastern equatorial Pacific could have had a detrimental effect on allowing this La Nina event to become established; however, there’s no evidence to suggest that occurred. If anything, La Nina has strengthened since then, and there are other signals to indicate that this has taken place. Figure 2 shows that not only sea surface temperatures are cooler in the central and eastern equatorial Pacific, but also, those temperatures are cooler below the surface.

Sub-surface sea surface temperature anomalies

Figure 2: Sub-surface sea surface temperature anomalies across equatorial Pacific

Based on the reasoning above, previous weak La Nina winters, along with a few low-end moderate La Nina winters, were selected when producing this forecast. These years were then filtered based on other criteria that will be briefly discussed in the next section.

Brief Forecast Discussion:

2017-18 Winter Forecast
Figure 3: Firsthand Weather’s official 2017-18 Winter Outlook

This winter is probably going to be characterized by a lot of volatility in the pattern, particularly in regions 8, 9, and 11. We’ve already seen quite a bit of that this month (November). If you happen to take a look at temperature anomalies across the United States for the first 10 days of this month, the below-average temperatures have extended from the Pacific Northwest to the central and northern Plains over to the Upper-Midwest and Great Lakes region. The coldest of those anomalies were centered over Montana and northern Plains. To the contrary, anomalous warmth has occurred from the southeast quadrant of the United States to the East Coast. BUT (this is important), southern regions of the U.S. east of the Great Plains have had intrusions of colder air, but it has come and gone. I foresee that happening quite a bit this winter, and at times over the winter, colder air masses may become established pretty far to the south for several days. Regions 4 and 10 are the only regions that I expect consistent warmth. Temperatures are going to be back and forth across many regions, even if some of these regions end up with average to slightly above average temperatures. Some regions, like Regions 2 and 5, could have intrusion after intrusion of Arctic air into the area with only brief warmups, at times. The battle zone region characterizes, on average, where I believe the boundary between colder and warmer conditions will persist (the baroclinic zone), which could ultimately become a zone of enhanced storm activity (including winter storm activity). Due to the volatile nature of this pattern, I wouldn’t be surprised if at least two winter storm opportunities arise in region 9, and while that’s not completely unusual, this will be a stark contrast to the last two winters.

It’s worth noting that after I selected the initial analog years, which was an aid in producing this forecast, I noticed that there was quite a bit of variability amongst the different years. A sizable proportion of those years featured warmer conditions across the southeastern U.S. and along the East Coast, while those same years also featured very cold conditions from the Pacific Northwest to the northern Plains. The magnitude of those anomalies varied year to year. However, there were a smaller subset of years that featured below-average temperatures into south-central and southeastern regions of the United States. There is research that indicates that the easterly phase of the quasi-biennial oscillation (QBO) increases the likelihood of there being a weaker stratospheric polar vortex, which in effect, would result in deeper intrusions of colder air. We have moved into the easterly phase of this oscillation, and it is something that I took into account when putting together this forecast. The colder intrusions that are expected later in November are the result of a weaker tropospheric polar vortex and blocking over the Arctic within the troposphere. With that said, the stratospheric polar vortex is currently well-established and is quite concentric over the Arctic. Over the course of the winter, I’ll be watching to see if the stratospheric polar vortex weakens and becomes better coupled with what’s going on in the troposphere. Due to the uncertainty that exists and the fact that conditions associated with “similar” years varied, confidence wasn’t high enough to predict below average temperatures in regions 9 and 10. Also, I went with a “temperatures will fluctuate a lot” for region 11. With all of that said, I decided to go with slightly above average temperatures in regions 9 and 10 and didn’t expand that region as far northwestward as I otherwise would have, given the current state of La Nina. As has already been mentioned in this forecast, there’s probably going to be a lot of large swings in temperatures anyway, which will open the door for more opportunities for snow/ice relative to the previous two years, even if temperatures end up around average or slight above that.

Region-by-Region Breakdown:

This section is meant to provide a synopsis of what is expected to occur this winter in a given region. Some of this information was already included in the previous section, but each regional discussion will be much more brief.

Region 1: This region will remain active throughout most of the winter. Rainfall/snowfall totals should be above average. However, there will be times that ridging may tend to build into the region, which may shift the overall storm track a bit farther north, but this won’t be a permanent occurrence. Temperatures should run below average across the northern half of this region, and average to below average across the southern half.

Region 2: There will be a tendency throughout the winter for Arctic cold air to spill into this region, which is why I believe temperatures will generally be below-average. Some colder intrusions could be centered to the east of the region towards the northern Plains, but this will be only during the times when ridging has temporarily become established across the western third of the U.S. Snowfall should run average to above average, making this a good ski season for this region.

Region 3: For this region, temperatures should run about average, and precipitation should generally be average to above average (sorry about the typo on the map). It’ll be difficult for any anomalously colder air mass to dig this far south into this region, but I don’t have any reason to believe that temperatures will consistently be above average either.

Region 4: This region should remain consistently warm and dry throughout most of the winter. Of course, there will be variability from time to time, but overall, this should be one of the few regions this winter that won’t have to deal with a lot of back and forth in temperatures/precipitation. Confidence is higher that temperatures will mostly be above average across the southern half of this region, while the northern half could have average to above average temperatures. It’s possible that northern parts of this region could get closer to their average snowfall, but snowfall totals should run below average to the south.

Region 5: This region will be very cold throughout the winter. Temperatures will generally be below average and in places, could be well-below average. Numerous intrusions of Arctic air will spill into the region, and if the expansive snow cover over Canada persists and continues to build, those air masses will be that much colder. Snowfall should generally be average to above average, with this winter featuring numerous opportunities for snowfall. Heavy lake-effect snowfall just prior to and early in the winter will likely occur.

Region 6: This was actually a difficult region to pin down, especially since it runs parallel to the wintry battle zone. Temperatures should generally run average to below average across this region. Numerous Arctic intrusions should spill into this region, but I went conservative on the temperature forecast since it appears that there will be noteworthy warmups in between all of this. Precipitation should be about average overall, but I wouldn’t be surprised if precipitation and snowfall totals go above average across the right half of this region. Expect heavy lake-effect snowfall just prior to and early in the winter.

Region 7: I don’t expect this region to be excessively warm this winter, but on the other hand, the majority of the brutal cold should remain outside of this region. I certainly can’t rule out some decent snows falling at times across the northern third of this region, but overall precipitation should be about average.

Region 8: This is the region that I classified as the “battle zone.” On average, this is where I expect the dividing line to be located between the very cold air to the north and slightly warmer conditions to the south. Notice that I said, “on average.” The challenging aspect of this winter is that I expect a lot of volatility throughout the winter. So, the coldest air could, at times, remain to the north, but other times, colder air masses could dig to the south of the region. Nonetheless, I expect an active storm track across this region and do believe a lot of this region will have a “real winter” this year.

Region 9: While temperatures will probably be slightly above average across this region, this is going to be quite a different winter compared to the last two. I don’t expect consistent warmth across this region like I do farther to the south, and this winter will be characterized by a lot of back and forth in temperatures. Some of the more noteworthy Arctic air masses will make it into this region. At least a couple of winter storms will likely be on the table, and there could be an additional ice storm threat or two just to the east and south of the Appalachians, due to cold air damming events. It could be in the 60s/70s one day with cold and snowy/icy conditions the next.

Region 10: While some colder intrusions could make it into this region throughout the winter, this area should stay consistently warm. Overall, temperatures should be slightly above average. Conditions should be mostly dry; however, the southern regions of the Delta could actually end up with precipitation close to average. It’s worth noting that a small subset of my analog years did depict consistently colder conditions into this region, but confidence simply wasn’t high enough to put that into the forecast.

Region 11: Yes, temperatures are going to fluctuate quite a bit across this region. That may not seem like an actual forecast, but given the volatility expected with the pattern, it’s the most fitting forecast for this region. Temperatures will have a greater likelihood of being closer to average near the coast but may actually end up below average farther to the west across this region. Snowfall totals will likely be average to above average across inland regions, but I can’t rule out the typical nor’easter or two this winter that could bring wintry conditions closer to the coast. However, many of the systems that impact this region will bring snow to inland regions, but rain near and along the coast.

Concluding Remarks:

This year, we’ll be including sub-seasonal forecasts throughout the winter. Even though it’s mid-November, there is a higher level of uncertainty this year, and I expect adjustments will have to be made to this forecast. Also, temperature/precipitation anomalies can vary spatially from month-to-month, and sometimes (depending on the year), a seasonal outlook that averages everything out over a 3-month period doesn’t give the full picture. What if you have dry conditions one month and wet the next month, which averages out to “normal?” Seasonal forecasts are great at giving you a general overview of what to expect, but they don’t provide the nitty-gritty details that a sub-seasonal forecast does. Since I expect many regions this winter to have larger swings in temperatures, those sub-seasonal forecasts should be very beneficial to you.

I encourage you to follow us on Facebook and Twitter throughout the winter, and again, sign up for our newsletter, which will include a lot of the sub-seasonal forecasts that I described above!

Accumulating Snow For Parts Of Texas and Oklahoma

Snow chances are increasing for parts of Texas and Oklahoma Tuesday night into Wednesday morning. A potent shortwave will traverse across the Southern Plains during this time frame, which will aid in the development of precipitation.

Shortwave moving into Southern Plains generating precipitation

The forecast soundings show a moist atmosphere throughout the entire column and a thermal profile conducive for rain transition to snow for much of the Oklahoma Panhandle, Texas Panhandle, and western parts of Oklahoma.

Forecast sounding Wednesday morning in western Oklahoma

The difficult part of this discussion is forecasting the snowfall accumulations and time in which the rain transitions to a rain/snow mixture followed to a transition to all snow. This makes snowfall accumulation forecasts extremely difficult, but a few inches may be possible in areas. The greatest chance for accumulating snowfall is in the Texas Panhandle and Oklahoma Panhandle; numerical guidance is indicating a dusting to an inch for much of this area. I do believe isolated 1-2″ amounts are possible.

Snowfall accumulations according to the NAM

FHWs snowfall forecast

The snow that falls Tuesday night into Wednesday should taper off, and accumulations melt, by early afternoon on Wednesday. Temperatures will remain chilly throughout the day.