Weather Forecast and Severe Weather Outlook for Wednesday, March 30th 2016

An enhanced risk of Severe Weather with a Significant chance for Tornadoes late on Wednesday in the Mississippi Rivery Valley while Blizzard warnings are active in the Rockies.  Expect Heavy rain with the potential for flooding in the Southeast over the next few days.

The current Surface Analysis

Today’s National Forecast Map

Forecast

A strong, early spring storm system will exit the Rockies and track through the Great Plains over the next few days. Widespread snow is expected for much of the Central and Northern Rockies and the surrounding areas. Periods of heavy snow is forecast primarily for Wyoming, but also southern Montana, northern Colorado and the western and central Dakotas through Friday afternoon. 1 to 2 feet of snow will be possible for east/southeast Wyoming.  The Beartooths and Big Horns may have 3-day accumulations exceeding 1 foot.  A vast portion of the Great Basin and Intermountain West have Winter Storm Warning and Advisories in effect. Blizzard Watches and warnings are in effect for north-central and eastern Wyoming. Very strong wind gusts will accompany this system, which will likely lead to blizzard and/or near-blizzard conditions.

Moisture will stream northward from the Western Gulf of Mexico into the Upper Midwest that will also move eastward to the Northeast by Thursday evening.

Showers and thunderstorms will develop along and ahead of the associated front over the Plains and Upper Great Lakes on Wednesday as Rain continues over the Upper Mississippi River Valley. There is an enhanced risk of Severe Weather associated with these thunderstorms with hail and wind expected and a significant chance for Tornadoes.  Please see the Severe Weather Analysis section for additional information.   These showers and storms will shift east through the Appalachians into the Mid-Atlantic by Thursday

Meanwhile, upper-level energy over the Great Basin into the Central Rockies will trigger snow over the region and expand into parts of the Central High Plains by Wednesday evening.  Overnight Wednesday the snow over the area will end briefly.  Another region of upper-level energy over South-Central Canada will move southward over the Northern High Plain curving into the Central Plains by Thursday evening.   The snow will move into the Northern Plains/Rockies by Thursday morning that will expand into the Central Rockies and Central High Plains on Thursday afternoon into evening.  Further South, rain will develop over parts of the Central Plains on Thursday morning into evening.

Elsewhere, upper-level energy over Florida will produce showers and thunderstorms for parts of the state on Wednesday.

As the moisture increases and the associated front begins to move further into Plains, the area of convection will shift into the Middle/Lower Mississippi Valley Wednesday evening into Thursday. The  risk area for Severe Weather will be focused over the Coast states/Tennessee Valley on Thursday as heavy rains move into the River Valleys and Great Lakes Region. Heavy rain will also be likely for southern and central portions of the United States, where Accumulations of 1 to 4 inches will be common through Friday.  Snow will continue over Wyoming up through Montana and the Western and Central Dakotas.

***Severe Weather Outlook for Wednesday***

Day 1 Risk

Area (sq. mi.)

Area Pop.

Some Larger Population Centers in Risk Area

ENHANCED

80,415

8,859,670

Dallas, TX…Fort Worth, TX…Arlington, TX…Plano, TX…Garland, TX…

SLIGHT

239,648

18,961,566

Memphis, TN…Oklahoma City, OK…Kansas City, MO…Omaha, NE…Tulsa, OK…

MARGINAL

168,882

12,377,725

New Orleans, LA…St. Louis, MO…Metairie, LA…Cedar Rapids, IA…Springfield, IL…

***Severe Weather Analysis***

Scattered Strong to Severe Thunderstorms will from across Eastern portions of Oklahoma and Texas up into Eastern Nebraska and move Eastward into the Mississippi River and Missouri River Valleys from Iowa down to Louisiana and Mississippi. The primary threat of Tornadoes will be greatest in Northern Louisiana, Southern Arkansas, and West Central Mississippi but there is a risk of Tornadoes over large portions of the plains and gulf coast states.  This risk will continue into the overnight hours in the Lower Mississippi River where the risk is greatest for Severe Weather on Thursday. Hail is also a major threat in this region.

Risk of Tornadoes

Risk of Hail

An upper level low pressure system is progressing eastward from the Rockies into the Central Plains is developing a surface low over the Central Plains which will move from the Plain into the Mid-Mississippi River Valley by Thursday morning. A warm front moving north from the Gulf of Mexico will move through the Lower Mississippi River Valley and the Ozarks while a Dryline develops and strengthens near the I-35 Corridor from Kansas into North Central Texas.  Tonight, a cold front overtakes the Dryline and moves through Kansas and Oklahoma.

A powerful upper level jet currently over the Mexico Texas border will move towards the Red River Valley and ArkLaTex region during morning and afternoon today. Low level warm moist air is already moving into the gulf coast and South Central Great Plains based on surface observations overnight Tuesday.  The warm front bringing this air into the region will continue to move north throughout the day. This will support moderate to strong buoyancy east of the Dryline that strengthens later on today.  Multiple rounds of thunderstorms are likely across the region as deep convection and wind shear allows for the development of organized convective clusters and supercells during the mid to late afternoon.  Very large hail will be possible in the supercells due to strengthening mid-level flow near the I-35 Corridor but the stronger low level flow needed for the development of tornadoes, will be to the east of I-35 near the Mississippi River Valley.

Further North in Nebraska and Iowa, strong to severe storms that form during the afternoon will be shorter lived. Limits on daytime heating due to cloud cover that moves north from the storms to the south and less moisture and buoyancy than southern locations will help limit thunderstorm growth but some hail, wind and even a tornado or two is not out of the question for areas in the warm sector.

Into the evening and overnight hours, Severe storms will be spreading across parts of the ArkLaTex and ArkLaMiss regions. The strengthening low pressure over the Central Plains will encourage strengthening of the low level jet as it moves east toward the Mississippi River Valley.  With Dewpoints expected to be into the 60s up through the I-20 Corridor, Supercell clusters and squall lines that form will have the potential to produce all severe modes well into the overnight hours including the possibility of a few strong tornadoes near the ArkLaMiss region.  This area is the at the greatest risk of severe weather for the day.

This week’s Flood Risk

Yesterday’s Storm Reports

Robert Millette

Staff Meteorologist

Firsthand Weather