Area Forecast Discussion

WHAT HAS CHANGED

00Z Aviation Discussion Updated.

No significant changes were necessary at this time.

KEY MESSAGES

- 1) Severe storms expected this afternoon and early evening.

DISCUSSION

KEY MESSAGE 1...

Mid level shortwave energy will dive south into the area into the afternoon hours, followed by a cold front late this evening into the overnight. As a cluster of elevated convection associated with this shortwave approaches our area, it will encounter a very moist and unstable environment, with convection becoming more surface based as it enters our CWA. CAPE values progged to approach 2000 to 4000 J/kg, and increasing shear values of 40 to 60 kts in the 0-6km layer, will result in potential for storms to become organized. Damaging winds are the primary hazard, with convection potentially organizing into lines/bowing segments, but with that being said, there is a tornado threat as well, with low LCL heights less than 1500m and 0-3km SRH greater than 250.

Timing of the severe activity is difficult to pinpoint, but appears most should occur in the afternoon to early/mid evening hours, with an additional round of convection expected with the front later tonight. It's possible some of this convection associated with the front could be low end severe, but with loss of heating, and any effects earlier convection has on the overall environment, confidence isn't high.

Lastly, with any storms that occur, flash flooding is a possibility, with the overall anomalously high PW are that continues to remain in place. This should mainly be a threat in locations that receive repetitive rounds of convection.

AVIATION /00Z WEDNESDAY THROUGH SUNDAY/

Heavy rain and strong thunderstorms will continue to produce IFR flight conditions at times this evening. Although activity will continue to taper off from west to east tonight, IFR or worse conditions are expected to develop in fog and stratus. CIGs/VIS will slowly improve to VFR after 12Z Wednesday.

Expect moderate southwest winds, with stronger gusts in storms this evening. Flow will then become calm to light out of the northwest after a front crosses the area tonight.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z THURSDAY... FORECAST CONFIDENCE: Medium

ALTERNATE SCENARIOS: Impacts due to thunderstorms could vary. Fog and/or stratus late tonight and Wednesday morning may be worse than currently forecast.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

DATE WED UTC 1HRLY 23 00 01 02 03 04 05 06 07 08 09 10 EDT 1HRLY 19 20 21 22 23 00 01 02 03 04 05 06 CRW CONSISTENCY H H H H L H H M H L L M HTS CONSISTENCY M H H H H H H H H L H H BKW CONSISTENCY M H H H H H H H H H H H EKN CONSISTENCY H H H H M M M M L H M M PKB CONSISTENCY M H H H H L M L M M H L CKB CONSISTENCY H H H H H H H M H M L H

AFTER 00Z THURSDAY... IFR valley fog each morning through Friday.

RLX WATCHES / WARNINGS / ADVISORIES

WV...Flood Watch until 2 AM EDT Wednesday for WVZ005>011-013>020- 024>034-039-040-515>523-525-526. OH...Flood Watch until 2 AM EDT Wednesday for OHZ067-075-076- 083>087. KY...Flood Watch until 2 AM EDT Wednesday for KYZ101>103-105. VA...Flood Watch until 2 AM EDT Wednesday for VAZ003-004.