702  
FXUS61 KRLX 222358  
AFDRLX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON WV  
658 PM EST FRI FEB 22 2019  
   
SYNOPSIS
 
 
OCCASIONAL RAIN CONTINUES ACROSS THE SOUTH OVERNIGHT. A SECOND  
UPPER LEVEL WAVE BRINGS HEAVY RAIN ACROSS PARTS OF THE AREA  
SATURDAY, THEN A COLD FRONT BLOWS THROUGH EARLY SUNDAY.  
 

 
   
NEAR TERM /THROUGH SATURDAY/
 
 
AS OF 745 PM FRIDAY...  
 
FORECAST REMAINS ON TRACK. ONLY MADE MINOR ADJUSTMENTS TO  
TEMPERATURES TO MATCH CURRENT OBSERVATIONS AND TRENDS. ALSO,  
ADDED SOME POPS TO THE SOUTHERN AREA AND INCREASED CLOUD  
COVERAGE.  
 
AS OF 240 PM FRIDAY...  
 
THIS AFTERNOON, WE SIT BETWEEN CENTRAL GREAT LAKES HIGH PRESSURE AND  
DEVELOPING LOW PRESSURE ACROSS THE MISSISSIPPI VALLEY. THE BOUNDARY  
BETWEEN, AIDED BY A FLAT WAVE AND JET ALOFT, STILL PRODUCES  
SHOWERS ACROSS SOUTHERN WV AND SOUTHWEST VA. SHOWERS WILL  
CONTINUE AS SUBTLE, WEAK WAVES MOVE ACROSS THIS BOUNDARY THROUGH  
TONIGHT. MEANWHILE, A TROUGH EJECTS FROM THE ROCKIES THIS  
AFTERNOON, TILTING NEGATIVELY AS IT DOES SO, AND CYCLOGENESIS  
COMMENCES IN THE LEE OF THE ROCKIES, TRACKING NORTHEAST WITH THE  
PARENT TROUGH.  
 
IN THIS REGION, STRONG WARM ADVECTION RENEWS PRECIPITATION  
ACTIVITY ALONG THE REMNANT FRONTAL BOUNDARY AND TRACKS THE  
BOUNDARY NORTHWARD AS A WARM FRONT SATURDAY. A BRIEF PERIOD OF  
FREEZING RAIN IS POSSIBLE UPON PRECIPITATION ONSET IN THE WV  
MOUNTAINS INTO THE HEADWATERS OF THE GREENBRIER BEFORE NEAR-  
SURFACE TEMPERATURES WARM ABOVE FREEZING, HOWEVER, MARGINAL  
TEMPERATURES AND MARGINAL PRECIPITATION CHANCES COINCIDING WITH  
FREEZING TEMPERATURES LED ME TO HOLD OFF ON THE ISSUANCE OF  
HEADLINES FOR THIS.  
 
WARM, MOIST 850 MB FLOW IS PROGGED TO SURGE TO AT LEAST 50KTS, WITH  
POCKETS OF 70 KTS POSSIBLE, IN RESPONSE TO A STRENGTHENING LOW  
AND SE-DIGGING TROUGH. THIS IN TURN KICKS MOISTURE TRANSPORT  
AND CONVERGENCE INTO HIGH GEAR ACROSS THE APPALACHIAN REGION.  
DEFORMATION FORCING ANALYSIS BRINGS INITIAL BANDS OF STRATIFORM  
RAIN IN FROM THE SOUTHWEST DURING THE PRE- TO NEAR-DAWN HOURS  
OF SATURDAY, SAILING NORTHEASTWARD THROUGH THE DAY. MOISTURE  
AVAILABILITY WILL NEAR 1.2" PWAT WITH THE INITIAL BATCH, HOWEVER  
CONVECTION TO THE SOUTH MAY ROB SOME OF THIS MOISTURE, AS  
SUGGESTED BY A FEW HI- RES MODELS COMING INTO VIEW. LOOKING AT  
POTENTIAL FOR 0.75-1.5" OF RAIN THROUGH SATURDAY WITH HIGHEST  
AMOUNTS LIKELY ALONG AND SOUTH OF THE I-64 CORRIDOR ACROSS THE  
TUG FORK VALLEY AND SOUTHERN ZONES. CONVECTION TO THE SOUTH OF  
THE AREA INTO NORTHEAST TENNESSEE WILL HAVE TO BE CLOSELY  
MONITORED - MUCH LOWER QPF IS POSSIBLE WITH MORE CONVECTION TO  
OUR SOUTH, HIGHER QPF AS MUCH AS 2-3" LOCALLY IS POSSIBLE  
SHOULD CONVECTION TO OUR SOUTH BE LIMITED.  
 
ANOTHER CONFLATING VARIABLE IN ADDITION TO SOUTHERN CONVECTION IS  
THE POSSIBILITY OF DOWNSLOPING FLOW FROM THE SOUTHEAST. MODEL  
ANALYSIS DOES YIELD A STRONG PRESSURE GRADIENT ACROSS THE  
APPALACHIAN SPINE, SUGGESTING SE/DOWNSLOPING FLOW, BUT IT APPEARS TO  
BE CHIEFLY TIED TO THE SURFACE. CURRENT THINKING IS THAT ROBUST  
SOUTHERLY/SOUTHWESTERLY FLOW AND MOISTURE TRANSPORT IN L/M LEVELS  
WILL OVERCOME THIS OBSTACLE THAT OFTEN FOILS HEAVY RAIN CHANCES IN  
SOUTH/CENTRAL PORTIONS OF WV. DOWNSLOPING MAY BECOME MORE OF A  
LIMITING FACTOR SHOULD CONVECTION STIFLE MOISTURE AVAILABILITY,  
HOWEVER.  
 
NO CHANGES WERE MADE TO THE EXISTING FLOOD WATCH WHICH  
PRESENTLY COVERS SOUTHERN WV, SOUTHWEST VA, EASTERN KY, AND  
PORTIONS OF SOUTHERN OHIO.  
 

 
   
SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/
 
 
AS OF 225 PM FRIDAY...  
 
VERY ACTIVE WEATHER WILL START OFF THE SHORT TERM PERIOD AS  
MOISTURE TRANSPORT CONTINUES TO MIGRATE IN FROM THE SOUTHWEST,  
RAMPING UP RAIN ACROSS THE OHIO RIVER VALLEY LATE SATURDAY NIGHT  
INTO SUNDAY MORNING. MODEL GUIDANCE IS IN FAIRLY DECENT  
AGREEMENT THAT THE SOUTHERN HALF OF THE CWA, ALREADY STRICKEN  
WITH VERY SATURATED SOILS, WILL LIKELY RECEIVE AN ADDITIONAL  
1-2 INCHES WITH THIS SYSTEM. THIS WILL POSE A CONCERN FOR THE  
SECOND HALF OF THE WEEKEND, BEGINNING WITH POTENTIAL FOR THUNDER  
LATE SATURDAY NIGHT. WHILE THE INSTABILITY STILL REMAINS LIMITED  
TO SUPPORT STRONG WINDS WITH ANY STORMS THAT DEVELOP, DOWNED  
TREES AND POWER LINES WILL STILL BE EASILY CAPABLE OF OCCURRING  
DUE TO THE WATERLOGGED SOILS. THIS THREAT CONTINUES INTO SUNDAY  
AFTER A COLD FRONTAL PASSAGE, WITH A STRONG GRADIENT MOVING  
INTO THE REGION IN ITS WAKE. WHILE FORECAST SOUNDINGS SLIGHTLY  
DEVIATE FROM ONE ANOTHER IN GUST POTENTIAL, GUSTS UP TO 30-40  
KTS ARE POSSIBLE ACROSS THE LOWLANDS WHILE THE MOUNTAINS ARE  
STILL SLATED TO SEE ANYWHERE UP TO 50-55 KTS IN GUSTS. WILL  
STILL HOLD OFF ON EXPANDING THE CURRENT HIGH WIND WATCH DOWN  
INTO THE LOWLANDS, BUT WILL PASS ALONG TO THE NEXT SHIFT TO  
MONITOR UPCOMING MODEL TRENDS. WIND GUSTS AND ANY RESIDUAL  
SHOWERS ALONG THE MOUNTAINS WILL TAPER OFF BY MONDAY MORNING AS  
HIGH PRESSURE BUILDS IN FOR THE FIRST HALF OF THE WORK WEEK.  
 

 
   
LONG TERM /TUESDAY THROUGH FRIDAY/
 
 
AS OF 220 PM FRIDAY...  
 
STARTING OFF THE LONG TERM UNDER MOSTLY ZONAL FLOW AND CLOSE TO  
SEASONABLE TEMPERATURES. HIGH CIRRUS BUILDS BACK INTO THE REGION  
AHEAD OF A WEAK COLD FRONT APPROACHING THE REGION TOWARDS  
MIDWEEK. PRECIPITABLE WATER VALUES REMAIN FAIRLY LOW WITH THIS  
SYSTEM, SO ONLY HAVE A SLIGHT CHANCE FOR SOME WINTRY WEATHER  
EARLY WEDNESDAY MORNING BEFORE CHANGING OVER TO RAIN FOR AREAS  
OUTSIDE OF THE MOUNTAINS SHORTLY AFTER DAYBREAK.  
 

 
   
AVIATION /00Z SATURDAY THROUGH WEDNESDAY/
 
 
AS OF 730 PM FRIDAY...  
 
THE BAND OF RAIN ASSOCIATED WITH THE FRONT TO THE SOUTH EDGES  
INTO THE AREA, HOWEVER IT MEANDERS FOR MOST OF THIS FORECAST  
PERIOD KEEPING RAINFALL CONFINED TO THE EXTREME SOUTHERN HALF OF  
THE STATE. A LOW PRESSURE SYSTEM WILL FORM ALONG THE BOUNDARY  
AND RIDE UP TOWARDS THIS AREA LATE SATURDAY MORNING BRINGING  
WIDESPREAD RAIN AND LOWER CEILINGS THROUGHOUT THE AREA. WITH THE  
EXCEPTION OF BKW ALL TERMINALS BY THEN WILL GO FROM VFR TO  
MVFR, WITH POSSIBLE IFR LATER IN THE DAY. BKW WILL BE IN AND OUT  
OF IFR CONDITIONS FROM NOW THROUGH SATURDAY. HTS/BKW WILL  
EXPERIENCE IFR CONDITIONS IN THE AFTERNOON, HOWEVER THE REST OF  
THE TERMINALS, WITH THE HELP OF SOUTHEASTERLY DOWNSLOPING  
LIFTING CEILINGS, WILL STAY IN MVFR. WIND OVERNIGHT IS OUT OF  
THE NORTHEAST GENERALLY AROUND 5KT. WINDS PICK UP OUT OF THE  
SOUTHEAST 5-10KT+ BY LATE MORNING. LOOK FOR GUSTS ON RUNWAYS IN  
THE UPPER TEENS IN LOW ELEVATIONS AND 20'S IN THE HIGHER  
ELEVATIONS.  
 
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY...  
 
FORECAST CONFIDENCE: MEDIUM.  
 
ALTERNATE SCENARIOS: VISIBILITY MAY VARY IN A HEAVIER RAIN  
SHOWER. LLWS MAY BECOME AN ISSUE AT THE BKW TERMINAL DURING  
SATURDAY AFTERNOON.  
 
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 SAT  
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11  
EST 1HRLY 19 20 21 22 23 00 01 02 03 04 05 06  
CRW CONSISTENCY H H H H H H H H H H H M  
HTS CONSISTENCY H H H H H H H H H H H M  
BKW CONSISTENCY L L L L L M H H H H H H  
EKN CONSISTENCY H H H H H H H H H H 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 H H H H H  
 
AFTER 00Z SUNDAY...  
IFR POSSIBLE IN RAIN CONTINUING THROUGH EARLY SUNDAY. STRONG,  
POSSIBLY DAMAGING, WINDS WILL IMPACT ALL SITES SUNDAY.  
 

 
   
RLX WATCHES/WARNINGS/ADVISORIES
 
 
WV...HIGH WIND WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING FOR  
WVZ030>032-039-040-521>523-525-526.  
FLOOD WATCH THROUGH SUNDAY MORNING FOR WVZ005>007-013>015-  
024>027-033-034-515>520.  
OH...FLOOD WATCH THROUGH SUNDAY MORNING FOR OHZ083-086-087.  
KY...FLOOD WATCH THROUGH SUNDAY MORNING FOR KYZ101>103-105.  
VA...FLOOD WATCH THROUGH SUNDAY MORNING FOR VAZ003-004.  
 

 
 

 
SYNOPSIS...MC/JZ/MEK  
NEAR TERM...MC/JZ  
SHORT TERM...MEK  
LONG TERM...MEK  
AVIATION...JZ  
 
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