462  
FXUS62 KRAH 192038  
AFDRAH  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE RALEIGH NC  
340 PM EST WED FEB 19 2020  
   
SYNOPSIS
 
 
A COLD FRONT WILL HOLD SOUTH OF THE AREA THROUGH TONIGHT, AS A LARGE  
AREA OF ARCTIC HIGH PRESSURE BUILDS INTO THE REGION FROM THE  
NORTHWEST. LOW PRESSURE WILL DEVELOP ALONG THE FRONT AND TRACK  
EASTWARD OVER THE SOUTHEAST STATES THURSDAY THROUGH THURSDAY NIGHT.  
HIGH PRESSURE WILL SETTLED OVER THE SOUTHEAST AND CAROLINAS FRIDAY  
THROUGH SUNDAY.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
AS OF 340 PM WEDNESDAY...  
 
PATCHY LIGHT RAIN HAS HELD ON OVER THE SE CWA, CORRESPONDING TO A  
PASSING MID LEVEL SHEAR AXIS. INTERESTINGLY, WE'VE HAD MULTIPLE  
REPORTS OF SLEET MIXING IN WITH RAIN WITHIN A NARROW SW-TO-NE BAND  
OF PRECIP NOW EXTENDING THROUGH THE TRIANGLE, LIKELY A FUNCTION OF  
THE DRYING JUST ALOFT AND SUBSEQUENT DROP IN THE WET BULB PROFILE,  
ALLOWING A FEW ICE PELLETS TO SURVIVE THE TRIP TO THE GROUND DESPITE  
SURFACE TEMPS THAT ARE WELL ABOVE NORMAL. NEVERTHELESS, AS THE  
ARCTIC SURFACE HIGH BEGINS TO BUILD IN FROM THE NW (ALBEIT WITH THE  
COLDEST AND MOST DENSE OF THIS AIR HOLDING WEST OF THE MOUNTAINS  
INITIALLY), THE REMAINING PRECIP IS EXPECTED TO PUSH TO OUR SE THIS  
EVENING, LEAVING PARTLY (N) TO MOSTLY (S) CLOUDY SKIES OVERNIGHT. WE  
MAY SEE SOME LIGHT PRECIP (MOST LIKELY A MIX OF LIGHT RAIN AND  
SLEET) SPREADING BACK INTO THE FAR SOUTHERN SECTIONS TOWARD MORNING  
AS THE UPPER LEVEL WAVE AND SURFACE LOW APPROACH FROM THE W AND SW,  
RESPECTIVELY, BRINGING IN RENEWED MOIST UPGLIDE AROUND 290K, BUT THE  
VAST MAJORITY OF CENTRAL NC WILL REMAIN DRY THIS EVENING THROUGH  
TONIGHT. EXPECT LOWS IN THE MID 30S TO AROUND 40. -GIH  
 

 
   
SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/
 
 
AS OF 200 PM WEDNESDAY...  
 
...WINTER WEATHER ADVISORY IN EFFECT FROM 10 AM THURSDAY TO 7 AM  
FRIDAY...  
 
CHANGES: STILL A GOOD BIT OF UNCERTAINTY WITH RESPECT TO AMOUNTS,  
THOUGH THERE WILL LIKELY BE A "SWEET SPOT" AND A TIGHT GRADIENT  
SOMEWHERE ACROSS CENTRAL NC. PRIMARY CHANGES FOR THIS FORECAST  
ISSUANCE INCLUDE AN EARLIER START TIME FOR SNOW, PARTICULARLY ACROSS  
THE NORTHERN HALF OF THE AREA AND AN UPTICK IN AMOUNTS ALONG THE I-  
85/US-64 CORRIDORS. WHILE THE OVERALL WEATHER PATTERN REMAINS  
SIMILAR TO PREVIOUS MODEL RUNS, CHANGES TO THE TEMPERATURE PROFILE  
ALOFT HAVE RESULTED IN A BIT MORE P-TYPE UNCERTAINTY. THERE WILL  
LIKELY BE A STRIPE OF WINTRY MIX ACROSS THE AREA AS THE RAIN MIXES  
AND TRANSITIONS TO SNOW ACROSS THE AREA.  
 
OVERALL PATTERN: A COLD FRONT WILL SETTLE SOUTH OF THE AREA, LAYING  
ACROSS SC/GA THURSDAY MORNING WITH COOL HIGH PRESSURE RIDGING  
SOUTHWARD AND ADVECTING COLD AIR INTO CENTRAL NC. WHILE THE SURFACE  
FRONT WILL REMAIN SOUTH OF THE NC/SC BORDER, ALBEIT PIVOTING SOME TO  
MORE SW/NE ORIENTATION, THE H85 FRONT WILL STALL OVER NC. AS A S/W  
ALOFT RIDES ALONG THE H85 FRONT FROM THE MS VALLEY TOWARD THE MID-  
ATLANTIC DURING THE DAY, A SURFACE LOW WILL DEVELOP OVER THE GULF  
COAST/SOUTHEAST US IN RESPONSE. WITH ABUNDANT MOISTURE ADVECTION  
ALOFT AND AND STRONG CYCLOGENESIS AT THE SURFACE OFF THE CAROLINA  
COAST THERE WILL LIKELY BE AN AREA OF STRONG FRONTOGENESIS OVER NC  
DURING THE AFT/EVE. THE COASTAL LOW WILL LIFT NORTHEAST ALONG THE NC  
COAST THEN EASTWARD OUT OVER THE ATLANTIC THROUGH THURSDAY  
EVE/NIGHT. MEANWHILE, THE PARENT UPPER TROUGH WILL SWING EASTWARD  
THROUGH THE OH/TN VALLEY TOWARD THE MID-ATLANTIC/NE THURSDAY NIGHT.  
PRECIPITATION WILL QUICKLY TAPER OFF AS THE UPPER TROUGH SWINGS  
THROUGH THE AREA, EXITING THE REGION EARLY FRIDAY.  
 
PRECIPITATION: RAIN WILL MOVE INTO THE AREA FROM THE SOUTH-SOUTHWEST  
EARLY THURSDAY. WITH THE COOL, DRY AIR IN PLACE THIS RAIN WILL HELP  
LOWER TEMPERATURES TO THE WET BULB TEMPERATURE (WHICH SHOULD BE IN  
THE 29-32 DEGREE RANGE), ESPECIALLY ACROSS THE NORTHERN HALF OF THE  
AREA. THE TRICKY PART OF THE PRECIPITATION WILL BE DETERMINING THE P-  
TYPE AND TRANSITION TIMES. THERE IS A BIG POTENTIAL FOR ERROR IN  
THIS REGARD, BUT THE MOST LIKELY SCENARIO WILL BE A QUICKER  
TRANSITION TO SNOW ACROSS THE NORTH WITH LOWER LIQUID EQUIVALENT  
PRECIPITATION TOTALS THAN ACROSS THE SOUTH. IN BETWEEN THERE WILL BE  
HIGHER CHANCES OF MIXED PRECIPITATION WHICH COULD LOWER THE OVERALL  
SNOW ACCUMULATION BUT POTENTIALLY CAUSE MORE ISSUES TRAVEL-WISE.  
BASED ON THE MODEL SIMULATIONS FROM THIS MORNING, THERE SHOULD BE A  
PERIOD OF ALL SNOW, MORE BRIEF IN SOME AREAS THAN OTHERS, ACROSS  
CENTRAL NC BETWEEN THURSDAY MORNING AND DAYBREAK FRIDAY. WHILE  
GENERALLY 0.5" TO 3" ARE MOST LIKELY ACROSS CENTRAL NC, THE MORE  
REALISTIC SCENARIO WILL BE A VERY LOCALIZED AREA OF HIGHER AMOUNTS  
AND A TIGHT GRADIENT FROM THAT TO TRACE AMOUNTS. OF COURSE, THE  
THERMAL PROFILE AND SNOW-LIQUID RATIOS WILL BOTH IMPACT THE OVERALL  
SNOW TOTALS WHEN IT'S ALL SAID AND DONE. AS PER USUAL, THE MOST  
SIGNIFICANT ACCUMULATIONS WILL OCCUR ON ELEVATED/GRASSY SURFACES.  
 
TEMPERATURES: HIGHS ON THURSDAY WILL OCCUR IN THE MORNING, TOPPING  
OUT IN THE UPPER 30S NORTH TO MID 40S SOUTH. TEMPERATURES WILL LOWER  
WITH THE ONSET OF RAINFALL, MORE QUICKLY ACROSS THE NORTH WITH  
TEMPERATURES IN THE MID 30S ACROSS THE AREA EXPECTED BY SUNSET.  
OVERNIGHT LOWS WILL DEPEND ON HOW QUICKLY THE LOW MOVES AWAY AND THE  
PRECIP ENDS, BUT GENERALLY EXPECT A STEADY DECREASE TO AROUND  
FREEZING UNTIL THE RAIN ENDS, WITH MORE RAPID COOLING IN ITS WAKE.  
FOR NOW, EXPECT TEMPERATURES COULD BE IN THE MID 20S NW TO UPPER 20S  
SE BY DAYBREAK FRIDAY.  
 
WINDS: WINDS SHOULD BE NORTHEASTERLY THROUGHOUT THE PERIOD. WHILE  
SUSTAINED WINDS WILL REMAIN IN THE 5-10 KT RANGE IN THE NW, GUSTING  
TO 10-15 KTS IN THE EVE/NIGHT, WINDS ACROSS THE SOUTHEAST (IN CLOSER  
PROXIMITY TO THE COASTAL LOW) WILL BE QUITE A BIT STRONGER AND  
GUSTIER. EXPECT SUSTAINED WINDS ACROSS THE SANDHILLS AND COASTAL  
PLAIN AROUND 15 KTS WITH GUSTS INTO THE MID 20S KTS.  
 
FRIDAY AND FRIDAY NIGHT: THE PRECIPITATION SHOULD QUICKLY EXIT THE  
AREA EARLY FRIDAY, WITH COOL, DRY WEATHER EXPECTED IN ITS WAKE.  
WINDS WILL CONTINUE TO BE A BIT BREEZY/GUSTY, STRONGEST IN THE EAST  
AND SOUTHEAST DURING THE DAY AND TAPERING OFF OVERNIGHT. SKIES  
SHOULD RAPIDLY CLEAR DURING THE DAY, BUT WITH THE WINDS HIGHS MAY  
REACH LOW 40S WEST WHILE TOPPING OUT IN THE UPPER 30S EAST.  
OVERNIGHT, CLEAR SKIES AND LIGHT WINDS WILL RESULT IN GOOD  
RADIATIONAL COOLING CONDITIONS WITH LOWS IN THE MID 20S EXPECTED.  
 

 
   
LONG TERM /SATURDAY THROUGH WEDNESDAY/
 
 
AS OF 300 PM WEDNESDAY...  
 
THE MID LEVEL SHORTWAVE TROUGH WILL BE PUSHING WELL OUT OVER THE  
ATLANTIC SAT MORNING, LEAVING BROAD RIDGING ALOFT AND AN EXPANSIVE  
SURFACE HIGH IN ITS WAKE. WE MAY SEE SOME OROGRAPHICALLY ENHANCED  
HIGH CLOUDS MAINLY SAT AND SUN MORNING/EARLY AFTERNOON, BUT  
OTHERWISE SKIES SHOULD BE MOSTLY CLEAR THROUGH MUCH OF THE WEEKEND,  
WITH TEMPS RUNNING A BIT BELOW SEASONAL NORMALS, PEAKING IN THE LOW-  
MID 50S SAT AND MID 50S TO NEAR 60 SUN.  
 
THE PATTERN LOOKS TO TREND MILD BUT A BIT UNSETTLED MON-WED, WITH A  
MEAN LONGWAVE TROUGH DEVELOPING TO OUR W. A PACIFIC-SOURCE LOW WILL  
CROSS CA AND THE DESERT SOUTHWEST BEFORE BECOMING AN OPEN WAVE AND  
CROSSING THE SOUTHERN PLAINS THROUGH SUN. THIS WILL DRAW THE SURFACE  
FRONTAL ZONE BACK NORTHWARD INTO THE AREA WITH A SURFACE LOW  
APPROACHING FROM THE WEST, SO EXPECT INCREASING CLOUDS SUN  
EVENING/NIGHT FOLLOWED BY OVERCAST SKIES AND RAIN CHANCES FOR SUN  
NIGHT THROUGH EARLY TUE AS THIS DAMPENING TROUGH AND SURFACE FRONTAL  
SYSTEM PASS THROUGH. WE MAY GET INTO A BRIEF RESPITE LATE TUE INTO  
EARLY WED, BUT A POLAR STREAM WAVE DIVING INTO THE CENTRAL/EASTERN  
STATES MAY BRING IN ADDITIONAL RAIN CHANCES LATE WED. TEMPS WILL  
GENERALLY PEAK IN THE MID 50S TO MID 60S, WITH LOWS HOLDING ABOVE  
THE FREEZING MARK. -GIH  
 

 
   
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
 
 
AS OF 1155 AM WEDNESDAY...  
 
A COLD FRONT HAS SETTLED JUST SE OF CENTRAL NC, BUT CLOUDS LINGERING  
BEHIND (TO THE NORTH OF) THE FRONT KEPT SUB-VFR CONDITIONS OVER  
RDU/FAY THROUGH LUNCHTIME, WITH 800-1500 FT AGL CIGS AND PATCHY RAIN  
AND DRIZZLE. AT INT/GSO AND AT RWI, WHERE DRIER LOW-LEVEL AIR PUSHED  
IN FROM THE N AND NE, RESPECTIVELY, CIGS BECAME VFR. AS THE DRIER  
LOW LEVEL AIR CONTINUES ITS SOUTHWARD PUSH, CIGS WILL RISE TO VFR AT  
RDU/FAY IN THE NEXT COUPLE OF HOURS. VFR CONDITIONS WILL THEN  
DOMINATE AT ALL CENTRAL NC TERMINALS THROUGH SUNRISE, AS COOL HIGH  
PRESSURE BUILDS INTO THE AREA FROM THE NW AND N. BUT CONDITIONS WILL  
DETERIORATE STARTING AS EARLY AS MID MORNING THU, AS THE FRONT TO  
OUR SOUTH HEADS BACK NORTH INTO NC, WITH A STRENGTHENING SURFACE LOW  
TRACKING EASTWARD ALONG THE FRONT. PRECIPITATION WILL BE SPREADING  
IN FROM THE SW IN THE MORNING, MOST LIKELY AS LIGHT RAIN MIXED WITH  
A LITTLE SLEET, BUT INT/GSO MAY CHANGE TO MOSTLY SNOW TOWARD THE END  
OF THE TAF VALID PERIOD (AFTER 16Z). CONDITIONS ARE EXPECTED TO  
DETERIORATE TO IFR AT INT/GSO NEAR 16Z AND AT RDU/FAY NEAR 17Z, WITH  
MVFR CONDITIONS POSSIBLE AFTER 17Z AT RWI.  
 
LOOKING BEYOND 18Z THU, ADVERSE AVIATION CONDITIONS (MAINLY IFR) ARE  
LIKELY THROUGH THE REST OF THU AND THU NIGHT AT ALL SITES, WITH  
SEVERAL HOURS OF WINTRY PRECIPITATION OR A MIXTURE POSSIBLE. VFR  
CONDITIONS ARE EXPECTED TO RETURN BEHIND THIS STORM SYSTEM STARTING  
FRI MORNING, ALTHOUGH LINGERING WINTRY ACCUMULATION COULD BE  
PROBLEMATIC ON PAVEMENT THROUGH FRI NIGHT. THESE VFR CONDITIONS ARE  
LIKELY TO LAST THROUGH SUN BENEATH HIGH PRESSURE. THE NEXT STORM  
SYSTEM WILL ARRIVE MON, BRINGING A GOOD CHANCE OF SUB-VFR CONDITIONS  
WITH RAIN. -GIH  
 

 
   
RAH WATCHES/WARNINGS/ADVISORIES
 
 
WINTER WEATHER ADVISORY FROM 10 AM THURSDAY TO 7 AM EST FRIDAY  
FOR NCZ007>011-021>028-038>043-073>078.  
 

 
 

 
SYNOPSIS...HARTFIELD  
NEAR TERM...HARTFIELD  
SHORT TERM...KC  
LONG TERM...HARTFIELD  
AVIATION...HARTFIELD  
 
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