759  
FXUS61 KRLX 231928  
AFDRLX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON WV  
328 PM EDT THU MAY 23 2013  
   
SYNOPSIS
 
 
SECOND COLD FRONT CROSSES THIS EVENING. UPPER DISTURBANCE CROSSES  
EARLY SATURDAY AND SUNDAY NIGHT. COOL CANADIAN HIGH PRESSURE  
ARRIVES TO START THE WEEKEND.  
 

 
   
NEAR TERM /THROUGH FRIDAY/
 
 
SHRA/TSRA ALONG A LLVL CONVERGENCE BOUNDARY IN C WV...WHICH WILL  
SHIFT E NEXT SEVERAL HRS. HAVE LKLY POPS WITH THIS AS IT WORKS  
INTO REMAINDER OF CWA LATER THIS AFTN. MAY SEE SOME MTN SHRA FORM  
AHEAD OF THIS ON DIFFERENTIAL HEATING. SHOULD SEE SOME DEEPER  
CONVECTION FORM SHORTLY WITH SOME SFC HEATING. LATEST SPC MESO  
DISCUSSION HAS PLACED MUCH OF WV ZONES IN POTENTIAL FOR WATCH. NOT  
SURE HOW STRONG CONVECTION WILL BE WITH LESS SFC INSTABILITY THAN  
PAST FEW DAYS. HOWEVER...FRZ LVLS ARE LWR AND BETTER UPR SUPPORT  
WITH APPROACH OF UPR TROF. DEEPER SHEAR A LITTLE BETTER THAN  
YESTERDAY AS WELL. DAMAGING WIND PROGS NOT AS IMPRESSIVE AS PAST  
FEW DAYS WITH MDLS SHOWING MARGINAL DOWNDRAFT SIGNAL AS SFC TO H7  
DELTA THETA E NOT AT GREAT. OF PERHAPS MORE CONCERN IS WATER.  
CONCERNED S PART OF THIS BOUNDARY MAY TRY TO TRAIN SOMEWHAT WITH  
THE BETTER PUSH ACROSS SE OH/N LOWLANDS INITIALLY. ALREADY SEEING  
THIS HAPPENING NEAR TRI STATE. 1 HR FFG HAS COME DOWN CONSIDERABLY  
WITH MUCH OF WV ZONES 1 TO 1.25 INCHES AND N LOWLANDS LESS GETTING  
DOWN TO .75. ISSUED FLASH FLOOD WATCH EARLIER FOR MUCH OF THE  
LOWLANDS AND N MTNS. WILL END IT AT 00Z WITH PWS COMING DOWN TO 1  
INCH.  
 
MAY SEE A FEW BANDS OF SCT SHRA/TSRA BEHIND THIS UNTIL UPR TROF AXIS  
AND COLD FRONT CROSSES THIS EVE. SHOULD SEE SOME POST FRONTAL  
SHRA CONT ALONG AND E OF I79 OVERNIGHT WITH LOW STRATUS DEVELOPING  
ELSEWHERE.  
 
CAA COMMENCES IN EARNIST LATE WITH H85 TMPS BOTTOMING OUT CLOSE TO  
0Z. NOT OUT OF THE QUESTION FOR SNOWSHOE TO SEE SOME WET  
SNOWFLAKES ARND DAWN. AS TROF AXIS PULLS E COLUMN COLUMN DRIES OUT  
CONSIDERABLY AND WILL ALLOW MORNING STRATUS TO MIX OUT IN MORNING  
WITH JUST SOME FLAT CU IN AFTN HEATING. WENT CLOSER TO MET FOR  
HIGHS WITH LWR 60S AND SOME 40S IN HIGHEST ELEVATIONS...DEFINITELY  
NOT INDICATIVE OF LATE MAY.  
 

 
   
SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/
 
 
HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES FRIDAY NIGHT TO  
PROVIDE DRY AND COLDER AIR UNDER NORTHERLY FLOW. DRY WEATHER  
CONTINUES THROUGH THE WEEKEND AS CALM FLOW UNDER HIGH PRESSURE  
SYSTEM EXTENDS INTO OH VALLEYS AND WV.  
 
CLEAR SKIES...CALM FLOW AND SOME COLD ADVECTION AT H850 WILL BRING  
TEMPERATURES AT OR BELOW FREEZING POSING A WIDESPREAD THREAT FOR  
GROWING VEGETATION TO FROST OR FREEZE INTO EARLY SATURDAY MORNING.  
 
KEPT POTENTIAL FOR FROST/FREEZE IN THE HWO.  
 
HIGH PRESSURE MOVES ACROSS THE AREA INTO TUESDAY TO PROVIDE MOSTLY  
DRY WEATHER. SOME CLOUDS WILL BE COMMON...AND A SHORTWAVE AT H5 BRINGS  
VORT MAXES SATURDAY NIGHT.  
 
WENT CLOSER TO SIMILAR MET/MAV NUMBERS FOR TEMPERATURES THROUGH  
THE PERIOD.  
 

 
   
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
 
 
HIGH PRESSURE REMAINS IN CONTROL TO AT LEAST EARLY WEDNESDAY  
PROVIDING DRY WEATHER WITH A SLOW WARMING TREND.  
 
ANOTHER MID LEVEL SHORTWAVE WILL MOVE THROUGH SUNDAY NIGHT FOR LOW  
CHANCE FOR RAIN SHOWERS INTO MONDAY.  
 
A WARM FRONT DEVELOPS AS IT APPROACHES THE REGION ON MONDAY. AS A  
RESULT...THERE WILL BE A CHANCE OF SHOWERS AND STORMS MONDAY AND  
TUESDAY...MAINLY DURING THE AFTERNOON AND EVENING HOURS.  
 
FOR SATURDAY...TEMPERATURES SHOULD BE NEAR NORMAL WITH DAYTIME  
HIGHS IN THE 70S ACROSS LOWLANDS...WITH 60S ACROSS THE HIGHER  
ELEVATIONS. TEMPERATURES WILL CONTINUE TO CLIMB IN THE UPPER TO  
MID 80S BY THE END OF THE WEEK. LOWS WILL RANGING IN THE 60S.  
 

 
   
AVIATION /19Z THURSDAY THROUGH TUESDAY/
 
 
LLVL CONVERGENCE BOUNDARY SERVING AS FOCUS FOR SHRA/TSRA THIS AFTN  
WHICH WILL SHIFT GREATEST COVERAGE INTO MTNS BY 21Z...BRINGING MVFR AND  
LOCALIZED IFR CONDITIONS...AND POSSIBLY GUSTY WINDS. HAVE SOME  
TEMPO GROUPS TO TRY AND COVER WITH VCSH AND VCTS IN THE  
PREDOMINATE GROUP. MAY SEE ANOTHER BAND OF SHRA AND ISO THUNDER  
WITH ARRIVAL OF UPR TROF AND COLD FRONT AFTER 00Z.  
 
EXPECT SOME POST FRONTAL SHRA TO LINGER OVERNIGHT...MAINLY IN  
MTNS. MVFR STRATUS TO DEVELOP AS WELL AT ALL TAF SITES WITH  
PERHAPS SOME IFR BASES IN MTNS. THIS WILL SCT OUT FROM W TO E IN  
THE MORNING WITH JUST SOME SCT FLAT CU FOR AFTN.  
 
W FLOW AND A BIT GUSTY THIS AFTERNOON...AS A SURFACE TROUGH MOVES  
THROUGH...AND THEN W TO NW AND GUSTY TONIGHT...AS A COLD FRONT  
MOVES THROUGH. LIGHT SW FLOW ALOFT THIS WILL BECOME W LATE  
TODAY...AND THEN MODERATE NW OVERNIGHT TONIGHT.  
 
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY...  
 
FORECAST CONFIDENCE...MEDIUM TO HIGH.  
 
ALTERNATE SCENARIOS: FORMATION...TIMING AND DEGREE OF FLIGHT  
RESTRICTIONS DUE TO CONVECTION THIS AFTERNOON INTO THIS EVENING  
COULD VARY. TIMING AND EXTENT OF MVFR /OR LOWER/ STRATOCU FORMING  
LATER TONIGHT COULD ALSO VARY.  
 
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.  
 
UTC 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07  
EDT 1HRLY 16 17 18 19 20 21 22 23 00 01 02 03  
CRW CONSISTENCY H H H H H M M H H M M M  
HTS CONSISTENCY H H H H H H M H H H H H  
BKW CONSISTENCY H H H H H H M M H L M M  
EKN CONSISTENCY H H H H H H H H L L M M  
PKB CONSISTENCY H H H H H H H H H H H H  
CKB CONSISTENCY H H H H H H H M M M M M  
 
AFTER 18Z FRIDAY...  
IFR CONDITIONS POSSIBLE IN FOG EARLY SATURDAY MORNING.  
 

 
   
RLX WATCHES/WARNINGS/ADVISORIES
 
 
WV...FLASH FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR WVZ008>011-  
013>020-025>032-038>040-046-047.  
OH...NONE.  
KY...NONE.  
VA...NONE.  
 

 
 

 
SYNOPSIS...ARJ/30  
NEAR TERM...30  
SHORT TERM...ARJ  
LONG TERM...ARJ  
AVIATION...30  
 
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