372  
FXUS61 KRLX 151038  
AFDRLX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON WV  
638 AM EDT WED AUG 15 2018  
   
SYNOPSIS
 
 
BRIEF UPPER LEVEL RIDGING EXITS TODAY. SEVERAL UPPER LEVEL  
DISTURBANCES TO THEN MOVE ACROSS THE AREA LATE THIS WEEK AND  
WEEKEND ALONG WITH A WEAK SURFACE FRONT. HIGH PRESSURE TRIES TO  
SNEAK IN EARLY NEXT WEEK.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
AS OF 635 AM WEDNESDAY...  
 
NO CHANGES OTHER THAN TO CLEAN UP THE WX GRIDS WITH LESS VALLEY  
ACROSS THE WESTERN LOWLANDS BEING REALIZED.  
 
AS OF 135 AM WEDNESDAY...  
 
VALLEY FOG WILL LIFT THIS MORNING INTO A CU FIELD, MASKED FROM  
TIME TO TIME BY PASSING CIRRUS. S/W RIDGING WILL GIVE WAY TO  
LOWERING HEIGHTS THIS AFTERNOON AS AN UPPER LEVEL SYSTEM  
ADVANCES TOWARD THE AREA. AHEAD OF THIS SYSTEM, A BAND OF WEAK  
LOW LEVEL MOISTURE CONVERGENCE WILL CROSS LATE IN THE DAY FROM  
THE WEST. THIS MAY SPARK A LATE DAY SHOWER OR STORM ACROSS  
SOUTHEAST OH OR NORTHEAST KY. HOWEVER, CURRENT THINKING IS THAT  
MID LEVELS REMAIN RATHER DRY AMID A DECENT CAP, SO ANY ACTIVITY  
WOULD BE ISOLATED AT BEST. TEMPERATURES WILL BE A BIT TOASTY,  
WITH MANY LOWLAND LOCATIONS TOPPING OUT IN THE UPPER 80S.  
HUMIDITY LEVELS WILL COME UP SLIGHTLY, BUT STILL NOT TOO BAD FOR  
THIS TIME OF YEAR.  
 
THE UPPER LEVEL SYSTEM DEAMPLIFIES A BIT TONIGHT AS IT REACHES  
THE OH VALLEY. HAVING SAID THAT, A DECENT LOW LEVEL JET IS  
EXPECTED TO DEVELOP ACROSS THE THE LOWER OH VALLEY, WITH  
IMPRESSIVE H85 MOISTURE ADVECTION SHOWING UP ON THE MODELS.  
THANKFULLY, THIS WILL REMAIN WEST OF THE AREA TONIGHT, SUCH THAT  
ONLY A FEW SHOWERS/STORMS ARE FORECAST ACROSS SOUTHEAST OH  
OVERNIGHT. DENSE VALLEY FOG SHOULD BE CONFINED TO THE MORE  
PROTECTED HOLLOWS AND MOUNTAIN VALLEYS WITH LOW LEVEL FLOW  
INCREASING, ALONG WITH SOME CLOUDS. TEMPERATURES WILL BE A BIT  
MILDER THAN PREVIOUS MORNINGS.  
 

 
   
SHORT TERM /THURSDAY THROUGH SATURDAY/
 
 
AS OF 317 WEDNESDAY...  
 
MOISTURE ADVECTION IS PROG TO INCREASE THROUGHOUT THE DAY  
THURSDAY, ESPECIALLY ACROSS THE WESTERN HALF OF THE CWA. DEEPER  
MOISTURE COMBINED WITH AN APPROACHING S/W TROUGH SHOULD RESULT  
IN SHOWER AND THUNDERSTORM DEVELOPMENT DURING THE DAY THURSDAY,  
WITH THE GREATEST COVERAGE ALONG/WEST OF THE OHIO RIVER. A  
MINOR, BUT NOTABLE, INCREASE IN SFC-6KM SHEAR VALUES MAY PROMOTE  
A STRONG TO SEVERE STORM THREAT BY LATE IN THE DAY, WITH LOCALLY  
SEVERE WIND GUSTS BEING THE PRIMARY STRONG STORM THREAT.  
 
PRECIP CHANCES THURSDAY NIGHT SHOULD INCREASE THROUGH THE NIGHT  
AS A SFC LOW DEEPENS ACROSS THE GREAT LAKES REGION AND A  
RESULTANT LLJ (30 KNOTS AROUND 925MB, PER GFS...NAM IS  
STRONGER) DEVELOPS ACROSS THE CWA. STRENGTHENING MOISTURE  
ADVECTION, ALONG WITH A POTENT MID LEVEL VORT S/W TROUGH AND A  
BIT OF A 50 TO 60 KT H25 JET STREAK SKIRTING INTO THE AREA  
SHOULD ALL AID IN OVERNIGHT CONVECTIVE DEVELOPMENT. GUIDANCE IS  
CURRENTLY INDICATING ALL OF THESE FEATURES INTERACTING THE MOST  
ACROSS WESTERN WV AND SE OH WHERE SOME LOCALLY HEAVY RAINFALL  
MAY OCCUR IN SOME OF THE STRONGEST AND PROLONGED CONVECTION. AN  
ISOLATED STRONG WIND GUST THREAT WILL ALSO PERSIST INTO THE  
EVENING HOURS.  
 
FRIDAY WILL FEATURE MORE OF THE SAME...CONTINUED CHANCES OF  
SHOWERS AND THUNDERSTORMS. LOCALIZED DYNAMICAL FORCING ON  
FRIDAY MAY BE A LITTLE LESS FOCUSED, WHICH MAY ALLOW FOR A  
LITTLE LESS IN THE WAY OF A STRONG STORM THREAT FOR MOST OF THE  
DAY.  
 
PARENT MID/UPPER LEVEL TROUGH IS CURRENTLY PROG TO PUSH ACROSS  
THE AREA FRIDAY NIGHT AND SATURDAY WHICH MAY ALLOW FOR A RENEWED  
FOCUS OF HEAVIER PRECIP AMOUNTS (PRIMARILY ACROSS THE SOUTHERN  
HALF OF THE CWA.  
 
FORECAST MAX TEMPS HAVE A HIGHER THAN USUAL BUST POTENTIAL  
DURING THE SHORT TERM PERIOD GIVEN EXPECTED CONVECTIVE CHANCES.  
 

 
   
LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/
 
 
AS OF 357 AM WEDNESDAY...  
 
SECOND HALF OF THE WEEKEND IS CURRENTLY FORECAST TO BE MUCH  
DRIER THAN THE FIRST HALF AS SOME WEAK RIDGING BUILDS OVERHEAD.  
ANOTHER STRONG TROUGH IS THEN PROG TO DIG INTO THE MIDWEST AND  
OHIO RIVER VALLEY TOWARDS THE END OF THE LONG TERM PERIOD WITH  
MOISTURE DEPTH THEN INCREASING ACROSS THE REGION AND POSSIBLY  
THE RETURN OF PRECIP CHANCES.  
 

 
   
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
 
 
AS OF 635 AM WEDNESDAY...  
 
ANY VALLEY FOG WILL LIFT BY 13Z. A CUMULUS DECK WILL THEN FORM  
MID MORNING AND WITH BASES GRADUALLY RISING DURING THE DAY,  
MASKED BY INTERVALS OF CIRRUS.  
 
A UPPER LEVEL SYSTEM WILL APPROACH TONIGHT, THOUGH ANY SHOWER OR  
STORM ACTIVITY WILL REMAIN WELL NORTHWEST OF THE TERMINALS. FOG  
TONIGHT MAY BE RESTRICTED TO EKN WITH LOW LEVEL FLOW INCREASING  
AND A BIT MORE CLOUD COVER.  
 
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY...  
 
 
FORECAST CONFIDENCE: HIGH  
 
ALTERNATE SCENARIOS: TIMING OF FOG FORMATION AND SUBSEQUENT  
DISSIPATION MAY VARY AN HOUR AT EKN TONIGHT.  
 
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 10 11 12 13 14 15 16 17 18 19 20 21  
EDT 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17  
CRW CONSISTENCY L M M H H H H H H H H H  
HTS CONSISTENCY L M L H H H H H H H H H  
BKW CONSISTENCY H H H H H H H H H H H H  
EKN CONSISTENCY M M M M H H H H H H H H  
PKB CONSISTENCY L L L H H H H H H H H H  
CKB CONSISTENCY M M L L H H H H H H H H  
 
AFTER 12Z THURSDAY...  
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS AT TIMES LATE  
FRIDAY THROUGH SATURDAY, ALONG WITH NOCTURNAL AND EARLY MORNING  
POST RAIN FOG, ESPECIALLY COME SUNDAY MORNING.  
 

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

 
 

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