304  
FXUS61 KRLX 170226  
AFDRLX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON WV  
1026 PM EDT TUE JUL 16 2019  
   
SYNOPSIS
 
 
THE REMNANTS OF BARRY CROSS WEDNESDAY INTO WEDNESDAY NIGHT.  
VERY WARM AND UNSETTLED THURSDAY. DANGEROUS AFTERNOON HEAT  
EXPECTED FRIDAY AND SATURDAY.  
 

 
   
NEAR TERM /THROUGH WEDNESDAY/
 
 
AS OF 1025 PM TUESDAY...  
 
MINOR EDITS TO THE OVERNIGHT LOWS, KEEPING THE POPS AS IS.  
ACTIVITY MAINLY WEST AND NORTH, BUT KEEPING WESTERN ZONE POPS IN  
DURING THE OVERNIGHT.  
 
AS OF 735 PM TUESDAY...  
 
BULK OF THE ACTIVITY REMAINS WEST OF THE AREA, WITH LITTLE WEST  
TO EAST COMPONENTS IN THE MOTION. UNTIL THE UPPER TROUGH GETS  
FURTHER EAST INTO THE OHIO VALLEY, WITH THE WANING OF THE  
HEATING, THE POPS ARE MORE WARRANTED ALONG THE WESTERN FRINGE  
OVERNIGHT.  
 
AS OF 210 PM TUESDAY...  
 
TWO AREAS TO FOCUS ON FOR PULSE TYPE SHOWERS/STORMS HEADING FOR  
THE REMAINDER OF THE AFTERNOON HOURS. ONE SUCH AREA IS PAINTED  
ACROSS THE RIDGETOPS IN POCAHONTAS/RANDOLPH COUNTY, AIDED BY  
WEAK SOUTHERLY FLOW FOR LIFT. HOWEVER, HIGH CLOUDS CONTINUE TO  
INHIBIT CUMULUS DEVELOPMENT WHICH HAS KEPT THE MOUNTAINS LARGELY  
VOID OF ANY PRECIP THUS FAR. AS A RESULT I'VE BACKED OFF ON  
POPS A BIT GIVEN THE CONTINUED CIRRUS CANOPY OVERHEAD. STILL  
EXPECTING SOME DEVELOPMENT LATER THIS AFTERNOON THOUGH.  
 
ELSEWHERE, MODELS INDICATE A RIBBON OF WEAK THETA E ADVECTION  
WORKING INTO THE AREA FROM THE WEST INTO THE AFTERNOON,  
ASSOCIATED WITH THE VERY OUTER PERIPHERAL OF POST TROPICAL  
CYCLONE BARRY. LATEST VISIBLE IMAGERY SHOWS AGITATED CUMULUS  
ACROSS EAST CENTRAL KY AND ALSO ALONG THE TUG FORK BASIN. THIS  
SHOULD SERVE AS AN INSTABILITY AXIS FOR AT LEAST ISOLATED  
CONVECTION AS IT PASSES. OTHERWISE, NO DISCERNIBLE AREAS OF  
FORCING TO LATCH ONTO FOR ANYTHING OTHER THAN ISOLATED COVERAGE.  
 
ANY SHOWERS OR THUNDERSHOWERS WILL QUICKLY WANE THIS EVENING.  
ATTENTION THEN TURNS TO THE APPROACHING REMNANTS OF BARRY. THE  
SURFACE REFLECTION WILL TRACK INTO THE OH VALLEY WEDNESDAY  
MORNING WHILE THE ASSOCIATED MID LEVEL S/W TROF AXIS CROSSES  
IN THE AFTERNOON. SHOWERS WILL OVERSPREAD SOUTHEAST OH DURING  
THE MORNING, EXPANDING INTO THE REMAINDER OF THE AREA AS THE DAY  
PROGRESSES. LIMITED INSTABILITY WILL HELP MITIGATE CONVECTIVE  
POTENTIAL. STILL, PWATS AROUND 2 INCHES AND A DEEP WARM CLOUD  
LAYER WILL LEAD TO EFFICIENT RAINFALL RATES. IN ADDITION, ANY  
POCKETS OF INSOLATION WOULD LEAD TO HIGHER INSTABILITY AND THUS  
A GREATER POTENTIAL FOR TORRENTIAL DOWNPOURS.  
 
BASIN WIDE QPF IS PROGGED TO BE LESS THAN INCH, BUT ISOLATED  
AMOUNTS TO 2 INCHES ARE CERTAINLY POSSIBLE SHOULD CONVECTION  
DEVELOP IN THE AFTERNOON. THE NORTHERN HALF OF THE CWA REMAINS  
WET WITH 1 AND 3HR FFG VALUES A BIT LOW GOING INTO THIS. STORM  
MOTIONS WOULD KEEP THINGS SOMEWHAT PROGRESSIVE, THOUGH THE  
POTENTIAL FOR BACKBUILDING EXISTS LATER IN THE DAY. I TOYED WITH  
THE IDEA OF A WATCH HERE, BUT AFTER COORDINATING WITH  
NEIGHBORING OFFICES, I'VE HELD OFF FOR NOW. MEANWHILE, THE  
SOUTHERN HALF OF THE AREA HAS BEEN QUITE DRY WITH GENERALLY 25  
PERCENT OF NORMAL OBSERVED PRECIP OVER THE PAST WEEK.  
 
SEVERE THREAT IS QUITE LOW, BUT NOT ZERO GIVEN SOME DIRECTIONAL  
SHEAR.  
 

 
   
SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/
 
 
AS OF 230 PM TUESDAY...  
 
SHORTWAVE TROUGH AXIS ASSOCIATED WITH THE REMNANTS OF BARRY WILL  
PUSH EAST OF THE REGION ON WEDNESDAY NIGHT. AS THE TROUGH PUSHES  
EAST AND INSTABILITY WANES, PRECIPITATION ACTIVITY WILL GRADUALLY  
DECREASE IN COVERAGE THROUGH THURSDAY MORNING. HOWEVER, NOT  
EXPECTING POPS TO COMPLETELY DIMINISH AS LOW LEVEL MOISTURE LINGERS  
BEHIND THE DEPARTING TROUGH. THUS, EXPECTING AREAS OF SHOWERS AND  
SOME EMBEDDED THUNDER CONTINUING INTO THURSDAY MORNING. IN ADDITION,  
PLENTY OF LOW CLOUDS AND/OR FOG WILL BE IN PLACE THURSDAY MORNING IN  
THE WAKE OF BARRY'S REMNANTS AND THE RAINFALL ON WEDNESDAY. THERE  
SHOULD BE SOME BREAKS IN THE CLOUD COVER BY THE AFTERNOON AS DIURNAL  
MIXING INCREASES, WHICH WILL ALLOW FOR AN OPPORTUNITY FOR THE  
ATMOSPHERE TO DESTABILIZE. MODELS ARE PROJECTING MODERATE  
INSTABILITY WILL BE IN PLACE WITH MLCAPE VALUES EXPECTED TO BE  
AROUND 2000-2500 J/KG, BUT FORECAST SOUNDINGS SUGGEST THAT DRIER AIR  
ALOFT WILL BUILD IN THROUGH THE DAY COURTEOUS OF BROAD HIGH PRESSURE  
ACROSS THE DEEP SOUTH. THIS COMBINED WITH THE MARGINAL SHEAR  
EXPECTED SHOULD LIMIT THE THREAT OF ANY ORGANIZED CONVECTION.  
HIGHEST POPS ARE EXPECTED TO BE ACROSS EASTERN AREAS GIVEN THE  
OROGRAPHIC INFLUENCE AMID NW FLOW IN THE MID/UPPER LEVELS, BUT ANY  
PRECIPITATION ACTIVITY SHOULD QUICKLY DIMINISH BY THURSDAY NIGHT.  
 
ATTENTION FROM HERE WILL TURN TO A STRONG UPPER LEVEL RIDGE THAT IS  
EXPECTED TO BUILD INTO THE REGION ON FRIDAY, WHICH WILL BE THE  
BEGINNING OF WHAT WILL BE A PROLONGED PERIOD OF DANGEROUS HEAT.  
MODELS SUGGEST THAT HEIGHTS ALOFT MAY REACH AS HIGH AS 594 DAM,  
YIELDING TEMPERATURES IN THE LOW/MID 90S AND DEWPOINTS IN THE MID  
70S ACROSS LOWER ELEVATIONS. THIS SHOULD SUPPORT HEAT INDICES AROUND  
OR SLIGHTLY ABOVE 105F. EVENTUAL HEAT HEADLINES WILL LIKELY BE  
NEEDED AND DID THINK ABOUT ISSUING AN EXCESSIVE HEAT WATCH TODAY,  
BUT AFTER SOME DISCUSSION WITH NEIGHBORING WFOS, WILL JUST CONTINUE  
TO MENTION IN THE HWO FOR NOW. IN ADDITION TO THE HEAT ON FRIDAY, A  
FEW ISOLATED SHOWERS AND STORMS WILL BE POSSIBLE. GREATEST THREAT  
FOR ANY CONVECTION ON FRIDAY WILL BE IN THE MOUNTAINS, BUT THE  
THREAT APPEARS TO BE VERY SMALL ACROSS THE LOWLANDS AS THE  
ATMOSPHERE WILL BE PRETTY CAPPED. HEAVY DOWNPOURS WILL BE THE  
GREATEST THREAT WITH ANY ACTIVITY THAT DOES DEVELOP AS SHEAR IS  
FORECAST TO BE ESSENTIALLY NON-EXISTENT.  
 

 
   
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
 
 
AS OF 233 PM TUESDAY...  
 
HIGH PRESSURE BUILDS BY THE END OF THE WEEK ALLOWING FOR LIGHT  
WIND, PLENTY OF SUNSHINE AND HOT AFTERNOON TEMPERATURES  
PARTICULARITY FRIDAY AND SATURDAY. MODELS SUGGEST H850  
TEMPERATURES WILL REACH 20C, WARMEST H850 SO FAR, SUGGESTING  
HOTTER SURFACE TEMPERATURES.  
 
WITH HIGHS IN THE MID 90S, AND DEW POINTS IN THE LOWER TO MID  
70S, APPARENT TEMPERATURES WILL RESULT INTO THE LOWER TO MID  
100S FRIDAY AND SATURDAY AFTERNOONS. THESE HEAT INDICES WOULD  
WARRANT HEAT ADVISORIES (100 DEGREES), OR EVEN EXCESSIVE HEAT  
WATCHES/WARNINGS (105 DEGREES). THE INTERVENING NIGHTS WILL BE  
OPPRESSIVELY WARM AND MUGGY. DIURNALLY-DRIVEN CONVECTION WILL  
BE A POSSIBILITY IN THE AFTERNOON WITH NO SHORTAGE OF HEAT AND  
HUMIDITY IN PLACE AS DEWPOINTS HOVER AROUND THE MID 70S. BY  
SATURDAY NIGHT, A NORTHERN STREAM TROUGH WILL PUSH A COLD FRONT  
INTO THE OHIO VALLEY.  
 
COLD FRONT EXPECTED NEXT WEEK COULD ALLEVIATE SOME OF THE HEAT.  
HOWEVER, ITS TIMING AND SOUTHWARD PROGRESS WILL DEPEND UPON THE  
TIMING AND AMPLITUDE OF THE DRIVING UPPER LEVEL SHORT WAVE  
TROUGH.  
 

 
   
AVIATION /03Z WEDNESDAY THROUGH SUNDAY/
 
 
AS OF 735 PM TUESDAY...  
 
NO TSRA IN THE FORECAST THROUGH THE REMAINDER OF THE NIGHT. PKB  
AND HTS ARE MOST PRONE AT THIS POINT AND MAY NEED A QUICK AMD  
IF A ROGUE CELL APPROACHES ONE OF THESE TERMINALS.  
 
THE TRIGGER FOR ALL OF THIS IS THE REMNANTS OF BARRY THAT ARE  
PUSHING EASTWARD THROUGH THE OHIO VALLEY. IT IS A SLOW PROCESS,  
BUT EXPECT AN INCREASE IN SHOWER CHANCES HEADING INTO WEDNESDAY.  
FOR NOW, NOT INCLUDING THUNDER IN THE FORECAST, BUT THIS MAY BE  
ADDED IN FOR THE LATE AFTERNOON HOURS WEDNESDAY WITH THE NEXT  
ISSUANCE.  
 
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z THURSDAY...  
 
FORECAST CONFIDENCE: HIGH.  
 
ALTERNATE SCENARIOS: NO FOG IN FORECAST. CLEARING MAY  
NECESSITATE AT EKN.  
 
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 07/17/19  
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11  
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07  
CRW CONSISTENCY H H H H H H H H H H H H  
HTS CONSISTENCY H H H H H H H H M M M M  
BKW CONSISTENCY H H H H H H H H H H H H  
EKN CONSISTENCY H H H H H M M M L L L L  
PKB CONSISTENCY H H H H H H H H H H H H  
CKB CONSISTENCY H H H H H H H H H H H H  
 
AFTER 00Z THURSDAY...  
IFR POSSIBLE IN SHOWERS WEDNESDAY NIGHT, AND IN LOW CLOUDS AND  
FOG DURING THE OVERNIGHT AND EARLY MORNING HOURS THURSDAY AND  
FRIDAY.  
 

 
   
RLX WATCHES/WARNINGS/ADVISORIES
 
 
WV...NONE.  
OH...NONE.  
KY...NONE.  
VA...NONE.  
 

 
 

 
SYNOPSIS...ARJ/30/RG  
NEAR TERM...26/30  
SHORT TERM...RG  
LONG TERM...ARJ  
AVIATION...26  
 
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