Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 270601 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 100 AM EST SAT DEC 27 2014 .SYNOPSIS...HIGH PRESSURE OVERHEAD THIS MORNING WILL SHIFT EAST OF THE AREA BY TONIGHT. A COLD FRONT WILL APPROACH FROM THE NORTHWEST ON SUNDAY... AND GRADUALLY MOVE SOUTHWARD THROUGH THE REGION ON MONDAY. && .NEAR TERM /THROUGH SATURDAY/... AS OF 840 PM FRIDAY... ANOTHER QUIET NIGHT WITH BOTH SURFACE HIGH PRESSURE AND MID LEVEL RIDGING OVERHEAD AND DEEP DRY AND STABLE AIR FROM THE SURFACE UP THROUGH 500 MB. A SLUG OF HIGHER LEVEL MOISTURE TRACKING AROUND THE PERIPHERY OF THE RIDGE... NOW MOVING OVER TN/KY/WV/VA... WILL AFFECT FAR NRN AND NW CWA WITH A PERIOD HIGH THIN CLOUDS... HOWEVER THIS IS UNLIKELY TO HAVE MUCH IF ANY IMPACT ON TEMPS. WINDS HAVE GONE CALM IN MOST AREAS... FACILITATING A GOOD TEMP DROP THIS EVENING. DEWPOINT DEPRESSIONS ARE ALREADY DOWN TO JUST A FEW DEGREES ESPECIALLY IN THE EAST... WHERE DEWPOINTS ARE GENERALLY HIGHER THAN IN THE WEST... AND THE LATEST HRRR DEPICTS AREAS OF FOG FORMING AFTER 09Z ALONG THE I-95 CORRIDOR. HAVE ADDED A MENTION OF FOG IN THE COASTAL PLAIN LATE TONIGHT INTO SAT MORNING. OTHERWISE... EXPECT MOSTLY CLEAR SKIES. LOWS 29-36... LOWEST IN OUTLYING AREAS. -GIH THE HIGH WILL BEGIN TO SLIP OFFSHORE ON SATURDAY AHEAD OF OUR NEXT SYSTEM. THE AIRMASS WILL UNDERGO FURTHER MODIFICATION AS RETURN FLOW SETS UP OVER THE REGION. HIGHS SHOULD RISE INTO THE UPPER 50S TO NEAR 60 DEGREES ACROSS THE NORTHWEST (WHERE MID/HIGH CLOUDS WILL BE FIRST TO ARRIVE) AND INTO THE LOW/MID 60S FURTHER SOUTHEAST. -KRD && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/... AS OF 305 PM FRIDAY... SATURDAY NIGHT...SW FLOW ALOFT WILL USHER IN A SERIES OF DISTURBANCES FROM THE NORTHERN GULF INTO THE SOUTHERN APPALACHIANS/MID-ATLANTIC REGION. LEAD DISTURBANCE PROJECTED TO ADVANCE TOWARD OUR REGION LATE SATURDAY NIGHT. MID LEVEL FLOW WILL GRADUALLY VEER IN RESPONSE TO THIS FEATURE...AIDING IN MOISTURE TRANSPORT INTO THE REGION. SFC RIDGE IS EXPECTED TO REMAIN ALIGNED WSW-ENE ACROSS CENTRAL NC...MAINTAINING A DRY AIR PRESENCE. LOW LEVEL ISENTROPIC LIFT ANEMIC DURING THIS PERIOD SO APPEARS LIFT GENERATED ALOFT FROM WAA. EXPECT DRY CONDITIONS THROUGH SATURDAY EVENING WITH PATCHES OF LIGHT RAIN SHOWING UP ON THE RADAR AFTER MIDNIGHT IN THE WEST. INITIAL PATCHES OF RAIN WILL GO TO MOISTEN THE SUB CLOUD LAYER. THUS...BEST SHOT OF MEASURABLE RAIN WILL LIKELY BE CONFINED TO THE FAR WESTERN-SOUTHERN PIEDMONT. SUNDAY...ATMOSPHERE EXPECTED TO REMAIN ADEQUATELY MOIST TO MAINTAIN CONSIDERABLE CLOUDINESS. LEAD PERTURBATION EXPECTED TO CROSS JUST WEST-NW OF OUR REGION IN THE MORNING. BULK OF PRECIP WITH THIS FEATURE SHOULD OCCUR IN VICINITY OF THE PIEDMONT COUNTIES WITH RAIN COVERAGE DECREASING TO THE SE. WILL TREND POPS FROM LIKELY NW THIRD TO CHANCE FAR SE. BY AFTERNOON...EXPECT NOTHING MORE THAN SPOTTY PRECIP AT THIS TIME WITH CHANCE POPS AREAWIDE. MAX TEMPS SUNDAY DEPENDENT ON AREAL EXTENT OF RAIN OR SHOWERS. FAVOR BLEND OF MOS GUIDANCE (UPPER 50S NW TO LOW-MID 60S SE). MORE EXTENSIVE/LONGER DURATION RAIN WILL RESULT IN COOLER TEMPS BY 3-4 DEGREES. SUNDAY NIGHT...MODEL GUIDANCE HAS GAINED SOME CONSENSUS ON A SLIGHTLY MORE PRONOUNCED PERTURBATION AND ATTENDANT SURFACE WAVE TO AFFECT OUR REGION SUNDAY NIGHT...ESPECIALLY AFTER MIDNIGHT. MAIN LIFTING MECHANISM APPEARS TO BE FROM A 140+ UPPER JET LIFTING NWD ACROSS THE NORTHERN MID ATLANTIC...PLACING CENTRAL NC IN THE FAVORABLE RIGHT ENTRANCE REGION. THIS MAY LEAD TO RAINFALL AMOUNTS ON THE ORDER OF A HALF INCH OVER THE PIEDMONT. PLAN TO TREND POPS FROM CHANCE IN THE EVENING TO HIGH LIKELY LATE SUNDAY NIGHT INTO THE FIRST PART OF MONDAY MORNING. LOWS IN THE MID 40S NW TO LOWER 50S SE. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 325 PM FRIDAY... MONDAY THROUGH FRIDAY... PERTURBATION ALOFT AND ASSOCIATED SURFACE WAVE AND FRONT WILL CROSS CENTRAL NC MONDAY MORNING. W-NW FLOW BEHIND THE EXITING WEATHER SYSTEM MONDAY AFTERNOON-NIGHT WILL LEAD TO DRIER AND MORE STABLE CONDITIONS. BASED ON CURRENT MODEL TIMING...FAVOR HIGHEST POPS MONDAY MORNING WITH DECREASING POPS MONDAY AFTERNOON AND LESS THAN 20 PERCENT POPS BY MONDAY NIGHT. TEMPS MONDAY DEPENDENT UPON EVENTUAL TRACK OF THE SURFACE LOW. SOME MODELS FAVOR A TRACK CLOSER TO THE NW PIEDMONT...PLACING BULK OF CWA IN THE WARM SECTOR. OTHER MODELS CLUSTER AROUND A SOLUTION WITH THE SFC WAVE CROSSING SC THEN UP ALONG THE NC COAST...PLACING CENTRAL NC IN THE COOL SECTOR. THE LATER SOLUTION SEEMS MORE LIKELY CONSIDERING THE POTENTIAL FOR A SHALLOW LAYER OF COOL AIR TO ADVECT INTO THE REGION BEHIND THE INITIAL PERTURBATION. HAVE TRENDED MAX TEMPS A LITTLE COOLER THAN MOS GUIDANCE BUT LATER FORECASTS MAY NEED TO TREND COOLER. TUESDAY THROUGH FRIDAY WILL FEATURE MAINLY DRY WEATHER WITH A COOLING TREND AS BROAD UPPER LEVEL TROUGH COVERS THE U.S. THE WLY FLOW ALOFT AND SFC HIGH PRESSURE DIVING SOUTHWARD ACROSS THE CENTRAL U.S. NORMALLY SIGNALS DRY AND SEASONABLY COOL CONDITIONS FOR OUR REGION. MAX TEMPS BY THE NEW YEAR WILL AVERAGE IN THE 40S TO NEAR 50 WITH MIN TEMPS IN THE 20S TO AROUND 30. && .AVIATION /06Z SATURDAY THROUGH TUESDAY/... AS OF 100 AM SATURDAY... WITH DEWPOINTS SLIGHTLY HIGHER OVER THE COASTAL PLAIN AND LIGHT WINDS...THERE MAY BE A COUPLE HOURS OF MVFR VSBY AT KRWI AND/OR KFAY PRIOR TO 12Z...ESPECIALLY AS SKIES PARTIALLY CLEAR BETWEEN SOME HIGH CLOUDS MOVING OVERHEAD. OTHERWISE.. VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE TAF PERIOD WITH LIGHT WINDS BECOMING SOUTH- SOUTHWESTERLY DURING THE DAY. MID-LEVEL CLOUDS WILL INCREASE LATER TONIGHT AND EARLY SUNDAY AHEAD OF A DISTURBANCE MOVING ALONG THE APPALACHIANS. HOWEVER...CURRENT MODEL PROJECTIONS HAVE LOW CLOUDS AND SUB-VFR CEILINGS SPREADING INTO THE KGSO/KINT VICINITY WELL AFTER 06Z SUNDAY. LOOKING AHEAD: A SERIES OF UPPER-LEVEL DISTURBANCES MOVING SOUTHWEST TO NORTHEAST ACROSS THE REGION COMBINED WITH AN APPROACHING FRONTAL ZONE WILL BRING A COUPLE ROUNDS OF LIGHT PRECIP AND SUB-VFR CONDITIONS TO PORTIONS OF CENTRAL NC SUNDAY AND MONDAY. CONDITIONS ARE EXPECTED TO IMPROVE BY LATE MONDAY NIGHT INTO TUESDAY. -KRD && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BLS NEAR TERM...HARTFIELD/KRD SHORT TERM...WSS LONG TERM...WSS AVIATION...BLS

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