Flash Flood in West Virginia, May 18, 2001

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG, VA
310 AM EDT FRI MAY 18 2001

RADAR SHOWING YET ANOTHER EXPANDING NOCTURNAL BAND OF SHRA/TSRA
MOVING ACROSS WVA INTO WRN VA ATTM. EXPECT BASED ON ETA WILL AGAIN
LIKE THE LAST FEW MORNS SEE WEAK VORT TAKE HEAVIEST ACTION ACROSS
THE WRN RIDGES BY DAYBREAK AND THEN INTO ERN AREAS THIS MORN BEFORE
CVRG DSIPTS. ONCE MORN TSRA FADES SHOULD SEE A LULL IN WDSPRD CVRG
THRU THIS AFTN AS BACKING FLOW ALF PER NRN 5H VORT CAUSES NEXT FEW
COMPLEXES TO PASS GNRLY TO OUR N/NW. THIS SHOULD FINALLY LIMIT ADTNL
MCS CVRG BUT EVEN SO...APRS MAY STILL HAVE ENOUGH ESE COMP TO
THICKNESS FLDS TO DRAG SHRA INTO NRN TIER CTYS ESPCLY THIS EVE. OTRW
EXPECT MAIN FOCUS LATER TDY ALONG WARM FRONT PASSING ACROSS THE BLUE
RDG AND INTO ERN VA BY LATE AFTN. GIVEN LACK OF MUCH SUPPORT ALF AND
INCRSG SFC-85H WAA CAN CUT HIGH MORN POPS WEST/NORTH TO GNRLY CHCY
THIS AFTN AND CONT CHCS ELSW ACROSS THE SOUTH. PER EXTRAPOLATION OF
HVY RAIN THRU THE CURRENT FFA AREA EARLY WILL CONT WATCH FOR MOST
AREAS THRU LATE MORN AND INCLUDE BATH CTY AS WELL. TEMPS CONT A BIT
TRICKY ESPCLY ERN ZONES WHERE STILL LEARY OF NOT SCOURING OUT LOW
LVL RH TIL MID/LT AFTN. GIVEN BIG JUMP IN THICKNESS VALUES ONCE MIX
OUT OCCURS WILL SEE AFTN TEMPS TAKE OFF WITH 1000-85H NUMBERS
SHOWING SOME MID 80S SRN HALF. WILL GO AHEAD AND BUMP UP HIGHS A BIT
WEST BUT CONT A BIT BLO MOS EAST WHERE GUID HAS BEEN WAY TOO FAST
WITH WAA.

CD FRONT PROGGED TO APCH THE AREA FROM THE NW TNGT AND WORK SEWD
THRU THE CWA BY SAT NGT. THINK ETA A BIT SLOW BUT AVN FAST WITH S/W
AXIS STILL HANGING BACK SO PLAN TO COMP TIMING OF FROPA TIL SAT EVE.
GIVEN SFC WAVE PASSING TWD DC LATE TNGT APRS BEST UVV TO STAY TO OUR
NORTH/WEST TIL DURING SAT. THUS WILL HAVE BEST HIGH CHC POPS OVRNGT
FROM LWB-ROA-LYH NWD AND TAPER BACK TO VRY LOW CHCS FAR SOUTH OTRW
PC TO MSTLY CLDY NORTH. FRONT CROSSING THE AREA FROM NW TO SE SAT
WITH BEST MCON ERN/SRN TIER CLOSER TO WEAK SFC WAVE WHILE BLYR TO
QUICKLY VEER TO NW WRN CTYS BY AFTN. THIS COVERED WELL VIA MORN POPS
NW AND OVERALL CHCY SCENARIO SE WHERE THE FRONT MAY LAG BACK A BIT.
PLAN TO BUMP UP HIGHS A NOTCH PER SLOWER FROPA...DVLPG DOWNSLOPE AND
IDEA THAT 85H CAA WONT BE REALIZED OUTSIDE SE WVA TIL LATE.

EXTENDED...BASED ON NEW GUID WILL SLOW DOWN ARRIVAL OF NEXT SHOT OF
SHRA/TSRA OUT EAST WITH FRONT MON OTRW FEW CHANGES FOR NOW.

FCSTID = 10
ROA   77  61  78  55 /  40  50  40  10
LYH   75  61  79  55 /  40  50  40  10
DAN   81  62  82  60 /  30  30  40   0
BLF   78  61  69  50 /  70  50  30  10
LWB   76  58  67  50 /  70  60  30  10
BCB   77  60  71  50 /  40  30  30  10
TNB   79  62  72  50 /  30  30  30  10

.RNK...
NC...NONE.
VA...FLASH FLOOD WATCH THIS MORNING VAZ007-010>011-018>020.
WV...FLASH FLOOD WATCH THIS MORNING WVZ042>045.

JH