547  
FXUS62 KRAH 210353  
AFDRAH  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE RALEIGH NC  
1050 PM EST MON FEB 20 2017  
   
SYNOPSIS
 
 
HIGH PRESSURE WILL EXTEND ALONG THE EAST COAST THROUGH EARLY  
TUESDAY. AN UPPER-LEVEL DISTURBANCE WILL CROSS THE SOUTHEAST STATES  
TUESDAY NIGHT INTO WEDNESDAY.  
 

 
   
NEAR TERM /THROUGH TONIGHT/
 
 
AS OF 1050 PM MONDAY...  
 
SCATTERED TO BROKEN COVERAGE OF CIRRUS EXISTED ACROSS THE REGION  
LATE EVENING. MOST OF THE HIGH CLOUDS WERE TOO THIN TO TEMPER  
COOLING. THE URBAN VS. RURAL LOCATIONS WERE REALLY NOTICEABLE GIVEN  
THE NEARLY CALM CONDITIONS AND THIN CIRRUS. READINGS AT 1000 PM  
RANGED FROM 60 AT THE WINSTON-SALEM URBAN LOCATED ASOS TO 46 AT THE  
RURAL SMITHFIELD, LOUISBURG, AND ROXBORO AWOS'S. SOME CIRRUS WILL  
CONTINUE TO OVERRIDE THE STRONG RIDGE AXIS JUST TO OUR WEST, LEADING  
TO PARTLY CLOUDY SKIES OVERNIGHT. LOWS ARE EXPECTED TO BE IN THE  
40S, WITH THE LARGE RANGE IN URBAN VERSUS RURAL LOCATIONS.  
 

 
 
   
SHORT TERM /TUESDAY AND TUESDAY NIGHT/
 
 
AS OF 350 PM MONDAY...  
 
THE SURFACE HIGH WILL CONTINUE TO EXTEND SOUTHWARD THROUGH EASTERN  
NC TUE AS ITS CENTER MOVES OFF THE COAST OF NEW ENGLAND. THE MID  
LEVEL RIDGE AXIS WILL ALSO MOVE OFFSHORE AS THE FULL-LATITUDE TROUGH  
APPROACHES FROM THE WEST. THIS TROUGH IS CURRENTLY PHASED BUT WILL  
SPLIT ON TUE, WITH THE NORTHERN PORTION DEAMPLIFYING AS IT  
PROGRESSES THROUGH QUEBEC AND THE NORTHEAST THROUGH TUE NIGHT,  
WHILE THE SOUTHERN PORTION DRIFTS MUCH MORE SLOWLY ALONG THE GULF  
COAST. IMPROVED OVERRUNNING FLOW AS THE 850 MB RIDGE AXIS SHIFTS OFF  
THE CAROLINA COAST TUE NIGHT ALONG WITH FALLING HEIGHTS WILL LEAD TO  
A CHANCE FOR SHOWERS IN WESTERN SECTIONS, MAINLY AFTER MIDNIGHT.  
FORCING FOR ASCENT WILL INITIALLY BE FAIRLY WEAK HOWEVER, AS THE  
WEAKENING MID LEVEL FLOW WILL LEAD TO WEAKER DPVA, ALTHOUGH UPPER  
DIVERGENCE WILL STEADILY IMPROVE. LOW LEVEL MOISTURE TRANSPORT WILL  
EXHIBIT A SMALL RISE OVERNIGHT OVER THE WESTERN CWA, WITH RISING  
PWS. THE NAM BRINGS MORE SUBSTANTIAL RAIN INTO OUR FAR NW TUE NIGHT  
AS COMPARED TO THE GFS/ECMWF, WITH MUCH HIGHER PW. THE MORE MUTED  
AND SLOWER GFS/ECMWF SOLUTION IS PREFERRED BASED ON ITS CONSISTENCY,  
THE WEAKER LOW LEVEL MASS CONVERGENCE, AND THE STRENGTH OF THE  
SLOWLY DEPARTING RIDGE AXIS, SO WILL ONLY BRING UP POPS INTO THE  
GOOD CHANCE RANGE IN THE NW TUE NIGHT, WITH LITTLE TO NO POPS  
ALONG/EAST OF HIGHWAY 1. WITH THE DIP IN THICKNESSES AND INCREASE IN  
CLOUDS TUE, WILL HAVE HIGHS IN THE MID-UPPER 60S, STILL WELL ABOVE  
NORMAL. LOWS TUE NIGHT IN THE MID 40S NE TO LOWER 50S S. -GIH  
 

 
   
LONG TERM /WEDNESDAY THROUGH MONDAY/
 
 
AS OF 247 PM MONDAY...  
 
THE PATTERN BEGINS TO CHANGE FOR MIDWEEK AND ALTHOUGH WE STAY WARM,  
A WETTER PATTERN WILL BRING MORE CLOUDS AND SOME CHANCES FOR RAIN  
LATE IN THE WEEK. THAT BEING SAID NO DAY LOOKS LIKE A WASHOUT AT  
THIS POINT AND RAINFALL TOTALS FOR THE WEEK LOOK ONLY TO BE ABOUT A  
HALF AN INCH AT THE MOST WITH SOME LOCATIONS RECEIVING VERY LITTLE  
RAIN. TEMPERATURES WILL REMAIN IN THE 60S AND 70S THROUGHOUT THE  
PERIOD.  
 
TO BREAK IT DOWN FURTHER, WEDNESDAY WILL BRING OUR FIST CHANCE FOR  
RAIN AS A LOW PRESSURE SYSTEM IN THE GULF OF MEXICO DIVES  
SOUTHEASTWARD TOWARDS THE FLORIDA PENINSULA. AS A SURFACE HIGH  
SINKS SOUTHWARD, CENTRAL NC WILL BE ON THE NORTHERN FRINGES OF THIS  
SYSTEM AND ANY RAIN THAT DOES OCCUR WILL BE A RESULT OF SOME  
ISENTROPIC LIFT AND MOISTURE ADVECTION FROM THE SOUTH. BEST CHANCES  
WILL BE IN THE WESTERN PART OF THE FORECAST AREA. ON THURSDAY A  
DEVELOPING LOW PRESSURE SYSTEM TO THE WEST WILL ESTABLISH A WARM  
FRONT ALONG OUR NORTHERN BORDER AND BEGIN TO ADVECT NORTHWARD. AS A  
RESULT, BEST CHANCES FOR ANY APPRECIABLE RAIN THURSDAY WILL BE ALONG  
THE VA BORDER COUNTIES.  
 
FOR THE MOST PART FRIDAY LOOKS DRY AS THE LOW TO THE WEST TRACKS  
NORTHEASTWARD INTO THE GREAT LAKES. AS IT DOES SO FRONTOGENESIS WILL  
OCCUR JUST WEST OF THE APPALACHIANS AS A COLD FRONT MOVES INTO NORTH  
CAROLINA SATURDAY MORNING AND ACROSS OUR AREA BY SATURDAY LATE  
AFTERNOON/EVENING. THIS MAY BE OUR BEST CHANCE FOR RAIN DURING THE  
LONG TERM WITH A NON-ZERO CHANCE OF SOME THUNDER, ESPECIALLY IN THE  
SOUTHEAST WHERE SOME BETTER INSTABILITY MAY BE ALLOWED TO DEVELOP.  
BEHIND THE FRONT, HIGH PRESSURE MOVES IN FOR SUNDAY SIGNALING A  
RETURN TO CLEAR SKIES AND DRY WEATHER.  
 

 
   
AVIATION /00Z TUESDAY THROUGH SATURDAY/
 
 
AS OF 720 PM MONDAY...  
 
24 HOUR TAF PERIOD: VFR CONDITIONS ARE GENERALLY EXPECTED TO  
CONTINUE FOR THE 24 HOUR TAF PERIOD AS A WEAK BACKDOOR COLD FRONT  
SINKS SOUTH-SOUTHWESTWARD INTO THE AREA. HOWEVER, A BRIEF PERIOD OF  
MVFR VISBYS ARE POSSIBLE AT KRDU OVER THE NEXT SEVERAL HOURS FROM  
LINGERING SMOKE FROM AN EARLIER FIRE NEAR THE AIRPORT. THERE IS A  
VERY SMALL CHANCE OF SOME LOW STRATUS AT KINT AND KGSO NEAR DAYBREAK  
AS WELL (WAY TOO LOW OF CONFIDENCE TO INCLUDE ANY SUB-VFR CONDITIONS  
IN THE TAFS THOUGH). OTHERWISE, VFR CONDITIONS ARE EXPECTED WITH  
GENERALLY LIGHT AND VARIABLE WINDS THROUGH THE PERIOD WITH ONLY SOME  
HIGH CIRRUS POSSIBLE.  
 
OUTLOOK: VFR CONDITIONS WILL HOLD THROUGH TUE EVENING. WE WILL SEE A  
CHANCE FOR LATE-NIGHT AND EARLY-MORNING SUB-VFR FOG/STRATUS REPEAT  
AREAWIDE EACH DAY THROUGH THE REMAINDER OF THE WEEK. MVFR TO IFR  
CONDITIONS WITH A FEW SHOWERS ARE POSSIBLE LATE TUE NIGHT THROUGH  
WED AS AN UPPER TROUGH CROSSES THE REGION. A COLD FRONT WILL CROSS  
THE AREA SAT, BRINGING A CHANCE FOR SHOWERS AND MVFR CIGS. -GIH  
 

 
   
RAH WATCHES/WARNINGS/ADVISORIES
 
 
NONE.  
 

 
 

 
 
SYNOPSIS...BADGETT  
NEAR TERM...BADGETT  
SHORT TERM...HARTFIELD  
LONG TERM...ELLIS  
AVIATION...BSD/HARTFIELD  
 
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