Disclaimer: This site is not affiliated with the National Hurricane Center, Hurricane Hunters, Storm Prediction Center, or National Weather Service. ALL forecasts herein are the result of my analysis, and I am solely responsible for the content.
(T. F. “Storm” Walsh III)
For those who have donated to my site, your help has been greatly appreciated. For those not aware, donations to my site help me offset my out of pocket expenses…such as some of the model maps you view on here, which are only available due to my subscription to the corresponding sites. The F5 Data maps I post as well, is another out of pocket expense (monthly subscription). Updates to software (weather related), and costs for my domain name are also out of pocket to me. To donate, please click the DONATE button to the right. Any help you provide is immensely appreciated!
Good day everyone!
The following PWO was issued by SPC earlier this morning:
PUBLIC SEVERE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0806 AM CST WED MAR 01 2017
…Severe thunderstorms expected over parts of the northern Tennessee, southern Kentucky, and far western Virginia area this morning…
Southern Kentucky Northern Tennessee Far western Virginia
Widespread damaging winds A couple of tornadoes Isolated large hail
Widespread wind damage is forecast across parts of Kentucky and Tennessee this morning. Severe thunderstorms will continue to spread across the Ohio and Tennessee Valley regions into the Middle Atlantic states, possibly into southern New England by mid afternoon. Damaging winds are the primary severe threat, though a few tornadoes and hail will be possible, especially west of the Appalachians.
Review your severe weather safety procedures for the possibility of dangerous weather today. Stay tuned to NOAA Weather Radio, weather.gov, or other media for watches and warnings. A watch means that conditions are favorable for severe thunderstorms over the next several hours. If a severe thunderstorm warning is issued for your area, move to a place of safety, ideally in an interior room on the lowest floor of a sturdy building.
The Storm Prediction Center (SPC) has designated the following risk area regarding the Day 1 Convective Outlook:
…THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF NORTHEAST MS…NORTHERN AL…AND SOUTHERN TN NORTHEASTWARD TO THE MID-ATLANTIC…
…THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SURROUNDING THE ENHANCED FROM PARTS OF THE LOWER MS VALLEY TO SOUTHERN NEW ENGLAND…
…THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING THE SLIGHT ACROSS PORTIONS OF THE EASTERN STATES…
SPC HAIL PROBABILITY
SPC DAMAGING WIND PROBABILITY
SPC THUNDERSTORM PROBABILITY TIMING MAPS (VALID TIMES LOCATED BOTTOM LEFT IN GRAPHIC)
STORM PREDICTION CENTER LINK
Severe thunderstorms with damaging winds are expected from portions of the Southeast to the Mid Atlantic region and parts of southern New England. Damaging winds will be likely, and the risk for tornadoes will exist particularly from parts of northeast Mississippi to portions of north Georgia and vicinity.
…Portions of the Southeast to the Mid-Atlantic region and southern New England…
An extensive belt of strong mid/high-level flow across the Southern and Eastern States will maintain strong deep shear over a moist and diurnally destabilizing warm sector across the area. A squall line from Middle TN toward the central Appalachians will likely spread across the adjacent Piedmont during the next several hours. Re-intensification of this activity is expected, owing to the presence of adequate moisture return (upper 50s to lower 60s dewpoints) amidst surface heating and relatively steep midlevel lapse rates. Swaths of damaging wind gusts will be likely as this activity spreads toward the coastal plain through the evening. A couple of tornadoes will be possible. Severe-wind probabilities have been increased eastward across the Piedmont area.
More separated updrafts/discrete convection are evolving across parts of the lower MS Valley, at the southern end of a zone of stronger deep ascent. As this activity spreads eastward toward parts of the southern Appalachians and vicinity, it will intercept a relatively more moist boundary layer supporting stronger instability further aided by steep midlevel lapse rates (around 8.5 C/km in the 700-500-mb layer per the 12Z Jackson sounding). With 250-350 m2/s2 of effective SRH associated with modestly curved though long hodographs, tornado probabilities have been increased in this area.
With northward extent across the East (i.e., toward southern New England and vicinity), weaker instability will exist owing to more widespread cloud coverage amidst an antecedent cooler/drier boundary layer. However, strong vertical shear profiles will support a conditional severe risk.
Modest destabilization may take place around the upper Ohio Valley and eastern Great Lakes area amidst recycled moisture ahead of the primary cold front, perhaps supporting a band of strongly forced convection spreading eastward from the late afternoon through the evening. Locally damaging wind gusts may accompany this activity.
At the time of my analysis, severe weather was ongoing, with a notable squall line making its way east at a pretty good clip. Based on the above information from SPC, and analysis of F5 DATA forecast soundings from both the RAP and NAM-WRF models, I had to incorporate both models, given the variance of the model run times, in order to make a time line. Modeling suggests the outlined areas have the highest probability from 12:00 NOON to late afternoon, for the occurrence of the strongest storms and probable tornadic cells, mainly embedded within the squall line. Based on running out the soundings to early evening, the severe weather is forecast to continue to move eastward, but should begin to lessen in severity after 3:00 – 4:00 p.m. CST.
NAM 12:00 P.M. CST
RAP 2:00 P.M. CST
NAM 3:00 P.M. CST
Modeling suggests that after 3:00 – 4:00 p.m. CST, an isolated area for severe weather may exist over west to central NC.
The following graphics are linked for you to receive up to date information on SPC Watches and Mesoscale Discussions. The NWS Hazard and Warning Display is linked. Click on the map, and then click on your area for up to date NWS Statements and Warnings. PLEASE, visit back often and click on the graphics for current, up to date information.
Have a blessed day!
T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS