Forecast and Severe Outlook: Monday, May 9th

Southerly winds ahead of an upper system moving out of the central Rockies into the Great Plains are forecast to draw warm, moist air from the Gulf of Mexico supporting widespread showers and thunderstorms across the lower and central Great Plains into the lower and mid Mississippi valley Monday into Monday night. Some of these storms may be strong to severe, particularly from northeast Texas, southeast Oklahoma into Arkansas and northwest Louisiana, where the air mass is expected to become highly unstable as well.

The current Surface Analysis

Surface map us

Today’s National Forecast

Weather Forecast map

Moisture spreading further to the north is likely to focus along a slow moving frontal band supporting widespread moderate to locally heavy rainfall accumulations across portions of the lower Missouri and mid Mississippi valleys.

On Tuesday into early Wednesday, the previously noted upper system is forecast to weaken as it continues to track to the east. Organized showers and thunderstorms are expected to focus along the frontal boundary that will continue to extend from the mid Mississippi into the Ohio valley and Mid-Atlantic states.

Back to the west, a well-defined cold front is forecast to drop through the western U.S. this period, with below-average temperatures spreading south and east from the northern Rockies and High Plains. Moderate to heavy precipitation is likely to develop west of an organizing area of low pressure over the northern High Plains. Heavy rain accumulations are expected to center over eastern Montana, with heavy mountain snows over the ranges of southwestern Montana and northwestern Wyoming.

Current Severe Weather Outlook

Fire Weather Update

Fire Weather

Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
Critical 35,626 780,783 Las Cruces, NM…Roswell, NM…Hobbs, NM…Carlsbad, NM…Artesia, NM…

Critical Fire Weather area for portions of Eastern New Mexico and Far West Texas.

Severe Weather Analysis

Summary

Severe storms are forecast Monday into Monday night from parts of the Southern and Central Plains eastward into the Lower to Mid Missouri Valley, the Ozarks, and ArkLaTex region. Tornadoes and very large hail are possible across the region under the enhanced risk from Eastern Oklahoma and Northeastern Texas into Central Arkansas and Northern Louisiana.

Severe Outlook

Day 1 Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
ENHANCED 67,531 4,070,056 Shreveport, LA…Little Rock, AR…Tyler, TX…Fort Smith, AR…Longview, TX…
SLIGHT 228,723 20,439,696 Dallas, TX…Oklahoma City, OK…Kansas City, MO…Omaha, NE…Tulsa, OK…
MARGINAL 203,583 16,544,671 Houston, TX…Memphis, TN…Fort Worth, TX…Arlington, TX…Pasadena, TX…

 

tornado risk

Day 1 Tornado Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
10 % 45,082 2,815,545 Shreveport, LA…Little Rock, AR…Tyler, TX…Fort Smith, AR…Longview, TX…
5 % 56,517 4,200,601 Tulsa, OK…Mesquite, TX…Broken Arrow, OK…Fayetteville, AR…Springdale, AR…
2 % 135,312 14,700,662 Dallas, TX…Fort Worth, TX…Oklahoma City, OK…Arlington, TX…Wichita, KS…

hail risk

Day 1 Hail Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SIG SEVERE 73,480 8,648,809 Dallas, TX…Tulsa, OK…Plano, TX…Garland, TX…Shreveport, LA…
30 % 67,798 4,097,285 Shreveport, LA…Little Rock, AR…Tyler, TX…Fort Smith, AR…Longview, TX…
15 % 229,629 20,571,862 Dallas, TX…Oklahoma City, OK…Kansas City, MO…Omaha, NE…Tulsa, OK…
5 % 202,489 16,100,321 Houston, TX…Memphis, TN…Fort Worth, TX…Arlington, TX…Pasadena, TX…

Analysis

Strong heating over much of the region will combine with steep lapse rates aloft to result in strong instability from Eastern Texas into Eastern Oklahoma and Kansas as well as Western Arkansas. Southerly low-level flow will continue to bring moisture into the region as it did with yesterdays storms.  Dewpoints are forecast to reach the mid to upper 60s across the region.  Thunderstorms currently near the Red River will shift into Arkansas by this afternoon.  There is a risk of damaging winds and hail with these storms.

The outflow from the aforementioned storms should help to focus the areas of severe weather development later this afternoon when instability reaches its maximum. Wind Shear profiles will clearly favor the development of discrete supercells and support conditions for tornadoes.  The most likely area for tornadic development will be Eastern Oklahoma into West Central Arkansas southward across the ArkLaTex region.  Supercells may also develop farther south within the moist regions near Shreveport.  Convergence in this area will be weak but rapid moistening and weakening outflow boundaries may be enough to initiate discrete storms.

Further west, from Central Oklahoma into Central Kansas, severe storm chances are more conditional along the Dryline but some storms should develop in this area and large hail is the primary risk.

Further north along the weakening warm front, strong warm advection pushing north will result in destabilization from Missouri into Western Illinois. A few severe storms capable of large hail and possibly a tornado or 2 cannot be ruled out.

This Week’s Flood Risk

Flood Risk

Yesterday’s Storm Reports

storm reports 2

Robert Millette

Staff Meteorologist

Firsthand Weather