Forecast and Severe Outlook: Friday, May 7th

As severe weather returns to the Plains, Fire Weather remains Critical in Eastern New Mexico after yesterday’s dry thunderstorms.  Today’s forecast and severe weather analysis follows below.

The current Surface Analysis

Today’s National Forecast

An omega block pattern aloft at the beginning of the period is forecast to slowly break down over the weekend. Well defined upper level lows are evident over the Desert Southwest and near the Mid-Atlantic coast Saturday morning, and a weakening upper level ridge over the Plains.  By Sunday afternoon, the pattern should not be quite as amplified with the upper low lifting northward towards Canada and the ridge becoming more suppressed to the south.

In terms of sensible weather, temperatures are expected to begin moderating across the eastern U.S. after several days of unseasonably cool weather and persistent cloudy skies. The same also holds true across much of the Intermountain West region with below normal temperatures likely to continue through the weekend, along with numerous showers and high elevation snow.  The heaviest snow is expected for the highest mountains of Wyoming, Utah, and Colorado.

Across the south-central U.S., it will become increasingly warm and humid as moisture returns northward from the Gulf of Mexico ahead of the upper low near the Rockies. Strong to severe thunderstorms will be possible from Texas to Nebraska on Sunday, and general thunderstorm activity is possible along a frontal boundary that will extend eastward to the Southeast U.S. coast.

Current Severe Weather Outlook

Fire Weather Update

Risk	Area (sq. mi.)	Area Pop.	Some Larger Population Centers in Risk Area
Critical	36,742	239,972	Roswell, NM…Clovis, NM…Carlsbad, NM…Portales, NM…Artesia, NM…

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

Severe Weather Analysis

Summary

Severe Thunderstorms are forecast to occur this afternoon and evening across the Central and Southern High Plains and the Ohio River Valley.

Day 1 Risk	Area (sq. mi.)	Area Pop.	Some Larger Population Centers in Risk Area
SLIGHT	95,499	9,079,542	Denver, CO…Cincinnati, OH…Aurora, CO…Lexington-Fayette, KY…Louisville, KY…
MARGINAL	347,529	20,467,273	Indianapolis, IN…Columbus, OH…St. Louis, MO…Pittsburgh, PA…Lincoln, NE…

Analysis

A southeastward moving trough over the Great Lakes will impact the high amplitude pattern in place and allow the closed low over Southern California to finally begin to move east. Surface cyclogenesis will occur over Northeast Colorado and the adjacent Central Plains as a southward moving front extends across the Middle and Lower Missouri Valley into the Ohio River Valley.

In the High Plains, Moist Southeasterly upslope flow will establish itself this afternoon and evening along the Front Range in Northern Colorado and Southern Wyoming. Storms are expected to develop and steadily increase by mid-day over the higher terrain and then move into the foothills and then over the High Plains.  Severe hail is expected and a coup-le of Tornadoes could occur particularly over Northeastern Colorado.

Further east, a cold front associated with a deepening low near the Great Lakes will amplify over the Ohio Valley. Persistent strong west southwesterly winds will feed moisture just above the surface and raise surface Dewpoints into the 60’s by late afternoon.  With near surface based storms expected to form this afternoon and evening, severe hail and winds should be the primary hazards.

This Week’s Flood Risk

Yesterday’s Storm Reports

Robert Millette

Staff Meteorologist

Firsthand Weather