A wet period for the Southeast

The ‘NWS Blend of Models’ is very aggressive with rainfall amounts over the Southeast (SE) over the next 9-days. It is possible this is overdone, but without a doubt, several inches of rain possible for a large part of the SE over the next week.

Figure 1: NWS Blend of Models rainfall accumulations

The Climate Prediction Center has a high probability of above average precipitation for the SE during this timeframe.

Figure 2: Climate Prediction Center 6-10 day precipitation probabilities

The SE needs rain because much of the region is ranging from abnormally dry to extreme drought conditions according to the most recent drought monitor. This amount of rain, however, is probably too much if these values were to verify.

Figure 3: Southeast drought monitor

Firsthand Weather will continue to have updates on this situation over the next few days.

Below average temperatures to end October for much of the country

October is forecast to end on a cold note across a large part of the country as a large pattern change takes shape. This pattern change will take shape by the end of the week, forcing cold air out of Canada into United States.

Watch the explanation on why cold air will slip south into the United Sates here: http://bit.ly/2NhoS5d.

Numerical guidance, which is referred to as “computer models” by meteorologists, is a tool meteorologists use to help determine the future state of the atmosphere (i.e. what will happen in your area tomorrow or in 5 days). This guidance is indicating a equatorial dip in the jet stream across the central United States as the Eastern Pacific Ridge and Greenland Block establish, creating a “buckle” of the jet stream. This will force the jet stream south, allowing cold air to readily flow into central parts of the country.

Figure 1: Late October upper-level pattern
Figure 2: Late October frequent cold fronts

The Climate Prediction Center (CPC) has highlighted the majority of central & western parts of the country for moderate to high probabilities of below average temperatures for days 6 through 10.

Figure 3: 6 to 10 day temperature outlook (CPC)

The CPC also has the same areas with moderate to high probabilities of below average temperatures for days 8 through 14, which will cross over from the end of October into the beginning of November.

Figure 4: 8 to 14 day temperature outlook (CPC)

Tropical Storm Nestor develops in the Gulf of Mexico: Expected to bring major impacts to the Southeast

Tropical Storm Nestor developed this afternoon in the north-central Gulf of Mexico according to the National Hurricane Center. Nestor has maximum sustained winds of 60mph and is rapidly moving NE at 22mph.

Figure 1: Tropical Storm Nestor Forecast Track

Nestor is forecast to make landfall Saturday morning in the Florida Panhandle as strong tropical storm (maximum sustained winds of 65mph), thus, Tropical Storm Warnings are in place for parts of coastal Florida. Within the Tropical Storm Warning, the main hazards are: flash flooding, tropical storm force winds, isolated tornadoes & coastal flooding.

Figure 2: Current Tropical Alerts

Nestor will bring heavy rain & wind to much of the Southeast this weekend as the storm moves inland. Wind shear is impacting the structure of the storm. Nestor is rather lopsided because of this shear, which will allow the heaviest rain to fall on the eastern & northern sides of the storm. Nestor’s quick movement will help limit rainfall totals but beefy rain amounts are still possible for parts of the Southeast through Sunday, which is much needed due to the drought conditions for much of the Southeast. Rain totals of 3-5″ are possible for much of the Florida Panhandle, southern & central Georgia and the Carolinas. Isolated 6″+ totals are possible across the Florida Panhandle & far southern Georgia. 

Figure 3: Forecast Rainfall Totals

Wind will be another issue for parts of the Southeast as Nestor moves inland. A Wind Advisory is in place for much of southern & central Georgia (this may be extended into South Carolina by tomorrow morning). Winds of 40-50mph are likely for southern & central Georgia. Winds of 30-40mph+ are possible in South Carolina. Many of the trees still have their leaves, so this will increase the likelihood of minor tree damage that may lead to power outages for the Southeast.

Figure 4: Forecast Wind Gusts
Figure 5: Forecast Wind Gusts
Figure 6: Forecast Wind Gusts

Nestor will exit the Southeast by Sunday afternoon.

Figure 7: Tropical Storm Nestor Forecast Track

Major Winter Storm to Impact Rockies & North-Central United States

A high-impact winter storm dump snow across the central & northern Rockies and much of the north-central United States beginning Tuesday (northern Rockies) and continuing into the weekend (north-central U.S.).

The local National Weather Service offices have issued Winter Storm Watches, Winter Weather Advisories & Winter Storm Warnings for parts of Montana, far northeast Idaho, northern Wyoming, far northwestern Nebraska and western South Dakota for the threat of heavy snow. It is likely additional winter weather alerts (Watches, Advisories & Warnings) will be issued over the next 12-36 hours.

Current winter weather alerts Rockies
Current winter weather alerts Plains

Snow will begin across the northern Rockies on Tuesday before slowly transitioning south and east on Wednesday into the western North & South Dakota and much of Wyoming.

Future radar Tuesday afternoon Rockies (Tropical Tidbits)
Future radar Wednesday afternoon Rockies (Tropical Tidbits)
Future radar Wednesday afternoon Plains (Tropical Tidbits)

The snow will continue spreading south and east on Thursday into much of Colorado, far northwestern Kansas, western Nebraska and advance into the central Dakotas. The Denver Metro will see its first snow of the season with accumulations likely.

Future radar Thursday afternoon southern Rockies (Tropical Tidbits)

By late Thursday night into Friday, it is possible light snow may extend as far south as northeast New Mexico and the Oklahoma & Texas Panhandles (rain/snow mix). Continuing through Friday into Saturday, the snow will advance into eastern North & South Dakota, Minnesota and western Iowa.

Future radar Thursday night southern Plains (Tropical Tidbits)
Future radar Thursday night northern Plains (Tropical Tidbits)

Moderate to heavy accumulations are likely for much of the northern & central Rockies as well as north-central parts of the United States. It is too early to determine specific snow amounts but travel issues can be expected from Colorado north into Wyoming and Montana as well as into the Dakotas. Strong winds will help reduce visibility along with heavy snow for the Dakotas and Minnesota.