Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 250758 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 258 AM EST SUN JAN 25 2015 .SYNOPSIS... HIGH PRESSURE WILL EXTEND NORTHEASTWARD FROM THE GULF COAST INTO THE CAROLINAS TODAY. A STRONG UPPER LEVEL DISTURBANCE AND SURFACE LOW PRESSURE WILL CROSS THE REGION MONDAY INTO MONDAY EVENING. A COLD FRONT WILL DROP THROUGH THE AREA LATE MONDAY NIGHT... THEN SETTLE TO OUR SOUTH THROUGH MID WEEK... AS HIGH PRESSURE BUILDS IN FROM THE WEST. ANOTHER LOW PRESSURE AREA AND COLD FRONT WILL CROSS THE REGION THURSDAY NIGHT INTO FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 255 AM SUNDAY... SATELLITE IMAGERY SHOWS OUR NEXT SYSTEM THAT WILL APPROACH THE AREA TRYING TO GET ORGANIZED OVER THE MIDWEST THIS MORNING BUT THIS WONT APPROACH UNTIL MONDAY MORNING...LEAVING US WITH SETTLED WEATHER FOR SUNDAY. AT THIS HOUR THERE ARE CLEAR SKIES AND LIGHT WINDS LEADING TO SOME FAIRLY COOL TEMPERATURES ACROSS THE REGION. THERE ARE A SMATTERING OF UPPER 20S STARTING TO COME INTO THE OBSERVATIONS AT THE USUALLY COLDER RURAL AREAS. THIS IS TO BE EXPECTED WITH THE FAIRLY GOOD RADIATIONAL COOLING CONDITIONS. THIS PATTERN COULD START TO CHANGE HOWEVER AS FORECAST SOUNDINGS SHOW FAIRLY GOOD ENVIRONMENTAL CONDITIONS FOR OROGRAPHIC CIRRUS AND WATER VAPOR SHOWS INCREASED MOISTURE HEADING TOWARDS THE APPALACHIANS. THAT BEING SAID..WINDS ARE FAIRLY WESTERLY AND THE TRAJECTORY OF THE MOISTURE COULD HAVE CIRRUS...IF IT OCCURS...ENDING UP PRIMARILY IN VA AS OPPOSED TO NC. REGARDLESS OF OROGRAPHIC ENHANCEMENT...HIGH CLOUDS ARE EXPECTED TO START TO OVERSPREAD THE AREA LATER THIS EVENING. OTHERWISE A FAIRLY NICE DAY AHEAD WITH HIGHS IN THE LOW 50S NW TO UPPER 50S SE. WINDS WILL BE OUT OF THE WEST BACKING TO SOUTHWESTERLY BY LATER IN THE DAY AT 5-10 KTS WITH SOME GUSTING TO 15 KTS POSSIBLE IN THE TRIAD LATE IN THE AFTERNOON. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... AS OF 255 AM SUNDAY... A CLIPPER SYSTEM WILL MOVE INTO THE AREA WITH THE SURFACE LOW TRACKING SOMEWHERE IN THE VICINITY OF NC. MODELS DISAGREE SLIGHTLY WITH THE SOUTHWARD EXTENT OF THE TRACK BUT IN GENERAL THE FIRST WAVE MOVES INTO NC MONDAY MORNING. SOME UPPER LEVEL DYNAMICS ASSOCIATED WITH THE LEFT EXIT REGION OF AN UPPER JET WILL HELP PROVIDE SOME LIFT ABOVE 500 MB BUT BELOW THAT...THE SURFACE LOW WILL BE JUST STARTING TO DEEPEN. THEREFORE LACK OF STRONG DYNAMICS AND SATURATION IN THE LOW LEVELS WILL HELP KEEP PRECIPITATION AMOUNTS AT BAY. IN GENERAL...THE BEST CHANCES FOR RAIN WILL BE ACROSS THE NORTH. FORECAST SOUNDINGS INDICATE THAT TEMPERATURES WILL BE WARM ENOUGH TO SUPPORT A LIQUID RAIN EVENT DURING THE DAY ON MONDAY. RAINFALL TOTALS WILL GENERALLY BE LESS THAN A TENTH OF AN INCH. HIGHS TEMPERATURES WILL BE TRICKY DUE TO TRACK OF THE LOW BUT EXPECT UPPER 40S NORTH TO LOW TO MID 50S SOUTH AS A GOOD STARTING POINT. LATER IN THE AFTERNOON THE LOW WILL EVENTUALLY REACH THE COAST AND REALLY START TO DEEPEN AND START TO IMPORT A LOT MORE MOISTURE OFF OF THE SOUTHWEST ATLANTIC. BY THIS TIME HOWEVER...LOW WILL BE FAR ENOUGH EAST FOR US TO HAVE TO WORRY ABOUT HEAVY RAIN THREAT HERE IN CENTRAL NC. THE ATTENTION AT THIS TIME WILL THEN TURN TO A SECONDARY WAVE ON THE HEELS OF THE FIRST WAVE DIVING DOWN THROUGH THE UPPER LEVEL LONGWAVE TROUGH. AT THIS TIME A COOLING AND DRYING TREND WILL HAVE INITIATED BUT THERE STILL COULD BE ENOUGH SATURATION FOR SOME PRECIPIATION. BY 00Z TUESDAY WETBULB TEMPERATURES WILL START TO REACH THE FREEZING MARK IN THE TRIAD...AND DOWN TO RALEIGH BY 06Z TUESDAY. IF SOME LINGERING MOISTURE IS LEFT...THERE COULD BE ENOUGH LIFT IN THE SECONDARY WAVE TO PRODUCE A QUICK RAIN OR SNOW SHOWER. THAT BEING SAID...FORECAST SOUNDINGS DRY OUT RATHER QUICKLY IN THE SNOW GROWTH ZONE...SO THE LIKELIHOOD OF THIS IS NOT VERY HIGH BUT IT IS POSSIBLE...ESPECIALLY FURTHER NORTH AND WEST. OTHERWISE EXPECT MOST PRECIPITATION TO BE LIGHT AND ALL LIQUID. OVERNIGHT MONDAY NIGHT INTO TUESDAY...TEMPERATURES ARE EXPECTED TO DROP TO OR BELOW FREEZING IN THE NORTHERN HALF OF THE CWA. WITH VERY COLD TEMPERATURES AND RAIN ENDING EARLIER IN THE DAY...THE QUESTION OF POSSIBLE BLACK ICE IS A LOGICAL ONE FOR EARLY TUESDAY MORNING. A COUPLE OF THINGS ARE STACKING UP AGAINST THIS AT THIS POINT. FIRST...WINDS WILL REMAIN NEAR 10 KNOTS AFTER THE PRECIPITATION ENDS...WHICH WAS ALREADY LIGHT AMOUNTS TO BEGIN WITH...SO IT IS ENTIRELY POSSIBLE THAT ROADS COULD BE DRY BEFORE TEMPERATURES DROP BELOW FREEZING. EVEN IF THEY ARE NOT...VERY WARM SOIL TEMPERATURES AND HIGHS EARLIER IN THE DAY NEAR 50 DEGREES WOULD BE HARD TO SUPPORT THE DEVELOPMENT OF ANY ICE. CANT RULE OUT A FEW ICY PATCHES BUT OVERALL THIS IS NOT EXPECTED TO BE A PROBLEM. LOWS MONDAY NIGHT IN THE LOW 30S. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 130 AM SUNDAY... TUE/TUE NIGHT: THE POLAR FRONT SHOULD HAVE SETTLED SOUTH OF NC... AS THE SURFACE LOW BOMBS OFF THE MIDATLANTIC COAST. SHEARED VORTICITY WILL CONTINUE TO STREAM SE AND EAST ACROSS THE CAROLINAS INTO THE BASE OF THE MEAN POLAR TROUGH. WE MAINTAIN A DECENT AMOUNT OF MOISTURE FROM 925 MB UP THROUGH 600 MB (WITH SOME VARIABILITY AMONG THE MODELS REGARDING SHALLOW DRY LAYERS THROUGH THIS DEPTH)... SO EXPECT TO RETAIN A GOOD AMOUNT OF CLOUD COVER THROUGH THE DAY... BUT ANY PRECIP IS APT TO BE QUITE PATCHY WITH ONLY TRACE AMOUNTS EXPECTED... AS LOW LEVEL FLOW TAKES ON A NORTHWESTERLY DOWNSLOPE COMPONENT. WILL LEAVE POPS UNDER 15%. DESPITE SOME LOW LEVEL MIXING... THICKNESSES DROP TO VALUES NEARLY 20 M BELOW NORMAL... SUGGESTING HIGHS FROM NEAR 40 NORTH TO THE UPPER 40S SOUTH WHEN FACTORING IN CLOUD COVER. THE COLUMN DRIES OUT TUE NIGHT AS HIGH PRESSURE SHIFTING OVER THE OH VALLEY ATTEMPTS TO PUSH OVER THE MOUNTAINS. WITH A SLACKENING MSLP GRADIENT AND LOWERING WIND SPEEDS UNDER CLEARING SKIES... EXPECT CHILLY LOWS WELL DOWN INTO THE 20S. WED-THU: THE MID LEVEL POLAR LOW OFF NEW ENGLAND LIFTS NORTHEAST WITH THE MEAN TROUGH FINALLY PUSHING EASTWARD OFF THE EAST COAST EARLY WED... LEAVING NC BENEATH WEAK MID LEVEL SHORTWAVE RIDGING. THIS WILL GENERATE MAINLY QUIET WEATHER AND A GRADUAL MODIFICATION OF TEMPS THROUGH MID WEEK AS SURFACE HIGH PRESSURE BUILDS ESE OVER THE CAROLINAS WED BEFORE PUSHING SOUTHWARD TO OVER FL AND OFF THE SE COAST THU. ANOTHER CLIPPER SHORTWAVE TROUGH MOVING THROUGH THE DAKOTAS AND UPPER MIDWEST WED NIGHT WILL CROSS THE SRN GREAT LAKES AND OH VALLEY REGION LATE THU... AND A SHOT OF WEAK MID LEVEL DPVA ACROSS NC ALONG WITH INCREASING UPPER LEVEL DIVERGENCE (IN THE LEFT EXIT REGION OF A STRENGTHENING UPPER JET ACROSS THE MID/LOWER MISS VALLEY INTO THE MIDSOUTH) AND ACCELERATING CYCLONIC LOW LEVEL FLOW INTO THE FORECAST AREA WILL LEAD TO INCREASING AND THICKENING CLOUDS WITH LOWERING BASES THU. EXPECT HIGHS WED MOSTLY IN THE MID-UPPER 40S WITH PLENTY OF SUNSHINE. LOWS IN THE MID-UPPER 20S WED NIGHT AND HIGHS THU IN THE UPPER 40S TO LOWER 50S... JUST A COUPLE OF DEGREES BELOW NORMAL. THU NIGHT-SAT: THE AFOREMENTIONED SHORTWAVE TROUGH COMING OUT OF THE OH VALLEY SWINGS THROUGH THE EASTERN STATES WHILE AMPLIFYING THU NIGHT THROUGH FRI NIGHT. THERE IS NOT MUCH MOISTURE RETURN AHEAD OF THE ASSOCIATED FRONT WITH PROJECTED PW VALUES JUST A BIT ABOVE NORMAL... SO DESPITE DECENT MID-LEVEL DPVA AND UPPER DIVERGENCE THU NIGHT/FRI MORNING... EXPECT ANY PRECIP TO BE BRIEF AND LIGHT... AND WILL KEEP POPS LOW. DRY WEATHER FOLLOWS FOR THE LATTER HALF OF FRI INTO FRI NIGHT... WITH INITIALLY BLUSTERY NW WINDS POST-FRONT WEAKENING FRI NIGHT. PLEASANT WEATHER SAT WITH BRIEF FLAT OR SHORTWAVE RIDGING BEHIND THE EXITING TROUGH WITH HIGH PRESSURE AGAIN NOSING INTO NC FROM THE GULF STATES. MODEL SOLUTIONS REALLY START TO DIVERGE HERE BUT WE MAY SEE YET ANOTHER CLIPPER WAVE DIVING THROUGH THE UPPER MIDWEST AND GREAT LAKES REGION SAT WITH SOME ADDITIONAL ENERGY EMANATING FROM THE CLOSED LOW OFF BAJA STREAKING EASTWARD INTO NC... MEANING INCREASING CLOUDS SAT. -GIH && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... AS OF 1250 AM SUNDAY... 24 HOUR TAF PERIOD: HIGH CONFIDENCE OF VFR CONDITIONS THROUGH THE 24 HOUR TAF PERIOD AS SKIES THIS EVENING ARE CLEAR AND WINDS ARE LIGHT AND OUT OF THE WEST OR SOUTHWEST. WITH DRY AIR IN PLACE AT THE SURFACE...DEWPOINT DEPRESSIONS ARE LARGE ENOUGH THAT FOG SHOULD NOT BE AN ISSUE THIS MORNING. SOUNDINGS INDICATE THEIR COULD BE SOME OROGRAPHICALLY ENHANCED CIRRUS THIS MORNING THAT COULD AFFECT KINT AND KGSO ALONG WITH SOME HIGH CLOUDS ASSOCIATED WITH THE NEXT SYSTEM THAT WILL GRADUALLY MOVE IN FROM THE WEST LATER ON TODAY. THERE COULD BE A BRIEF PERIOD OF GUSTY WINDS AT KINT AND KGSO MAINLY BETWEEN 18Z SUNDAY AND 00Z MONDAY. LONG TERM: THE NEXT CLIPPER SYSTEM WILL BRUSH NORTHERN LOCALES ON MONDAY WITH PRECIPIATION EXPECT TO FALL AS RAIN. THIS MAY CAUSE SOME PERIODS OF SUB-VFR CONDITIONS MONDAY INTO TUESDAY MORNING. VFR CONDITIONS WILL RETURN FOR MIDWEEK WITH A WEAK SYSTEM FOR THURSDAY NIGHT POSSIBLY PRESENTING SOME ADVERSE CONDITIONS BUT CONFIDENCE IN THAT IS LOW AT THIS TIME. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...ELLIS SHORT TERM...ELLIS LONG TERM...HARTFIELD AVIATION...ELLIS

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