030 
FXUS62 KILM 191053
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
653 AM EDT TUE MAR 19 2013

.SYNOPSIS...
A STRONG COLD FRONT WILL SWEEP ACROSS THE AREA THIS MORNING. HIGH
PRESSURE WILL FOLLOW...BRINGING INCREASINGLY DRY AND COOL
CONDITIONS MID AND LATE WEEK. CLOUDY AND DAMP CONDITIONS WILL
DEVELOP FOR THE LATTER HALF OF THE WEEKEND INTO EARLY NEXT WEEK AS A
STORM SYSTEM MOVES UP THE MISSISSIPPI VALLEY WHILE A COASTAL
TROUGH DEEPENS OVER THE SOUTHEAST. 

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 6 AM TUESDAY...LOW STRATUS AND PATCHY TO AREAS OF FOG HAVE 
ENVELOPED THE AREA IN THE WAKE OF LAST NIGHT'S SHOWERS AND 
THUNDERSTORMS. DENSE FOG IS NOT EXPECTED...AND VISIBILITIES WILL 
BECOME UNRESTRICTED BY 9 AM. A STRONG COLD FRONT WILL CROSS THE 
FORECAST AREA...FROM W TO E...THIS MORNING. WITH ITS PASSAGE WINDS 
WILL SHIFT TO THE NW. THE FRONT WILL USHER IN DRY AIR...BUT THE 
CHILLY AIR WILL ARRIVE MORE GRADUALLY. A RIDGE OF CHILLY HIGH 
PRESSURE WILL BUILD IN FROM THE W THROUGH TONIGHT.

UNTIL THE COLD FRONT MOVES OFFSHORE 13-15Z... THERE REMAINS A SMALL 
CHANCE FOR SHOWERS. RAINFALL AMOUNTS OVERNIGHT WERE GENERALLY IN THE 
RANGE OF ONE-QUARTER TO ONE-HALF INCH WITH A FEW SPOTS RECEIVING 
CLOSER TO THREE-QUARTERS OF AN INCH. WHERE ADDITIONAL RAINFALL DOES 
MATERIALIZE THIS MORNING...AMOUNTS WILL BE LESS THAN A FIVE 
HUNDREDTHS OF AN INCH.

OTHERWISE...IN THE WAKE OF THE COLD FRONT...SKIES WILL CLEAR AND 
PRECIPITABLE WATER VALUES WILL DROP TO LESS THAN ONE-THIRD OF AN 
INCH. THE CLEARING WILL OCCUR FROM W TO E AND LASTLY ACROSS THE CAPE 
FEAR REGION THIS AFTERNOON. GIVEN THE DEVELOPING SUNSHINE AND WITH 
ONLY A GRADUAL COOLING OF THE COLUMN...MAXIMUM TEMPS SHOULD BE ABLE 
TO REACH CLOSE TO THEIR FULL POTENTIAL...LOWER TO MID 70S THIS 
AFTERNOON. EVEN THE IMMEDIATE COAST WILL WARM TO AROUND 70 DEGREES 
GIVEN THE SUBSIDENT OFFSHORE FLOW. WINDS WILL BECOME GUSTY FROM THE 
NW...UP TO 20 TO 25 MPH. AS TEMPS WARM AND DRY AIR BUILDS INTO THE 
REGION...RELATIVE HUMIDITY VALUES WILL DROP TO 25 TO 35 PERCENT THIS 
AFTERNOON.

AS THE COOL AIR CONTINUES TO BUILD ACROSS THE EASTERN CAROLINAS 
TONIGHT...TEMPS WILL GO FROM ABOVE NORMAL BY DAY TO BELOW NORMAL.
IDEAL RADIATIONAL COOLING CONDITIONS DO NOT HAVE A CHANCE TO FULLY 
DEVELOP WITH SOME WIND...ALBEIT LIGHT...FOR MOST OF THE NIGHTTIME 
HOURS...AS COLD AIR ADVECTION CONTINUES. ALSO...PATCHY TO BROKEN 
MID-CLOUDS...ASSOCIATED WITH A MID-LEVEL TROUGH...ARE EXPECTED TO 
MOVE INTO THE AREA LATE TONIGHT. STILL...EVEN WITH THESE MODERATING 
INFLUENCES...LOWS SHOULD FIND THEIR WAY INTO THE UPPER 30S WITH SOME 
MID 30S IN THE COOLEST SPOTS WELL INLAND. NEAR THE COAST...TEMPS 
SHOULD BOTTOM OUT AROUND 40 DEGREES.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...BROAD AREA OF LOW PRESSURE WILL BE LOCATED
OVER THE NORTHEAST WHILE STRONG RIDGE OF HIGH PRESSURE EXTENDS
FROM CENTRAL CANADA DOWN THROUGH THE MIDWEST EXTENDING EAST
REACHING INTO THE CAROLINAS. SHORTWAVE WILL RIDE AROUND THE BASE
OF THE BROAD TROUGH ON WEDNESDAY PUSHING A DRY COLD FRONT THROUGH
THE AREA BY WED NIGHT. ALSO WILL BE A DECENT JET MOVING ALONG THE
BASE OF THE TROUGH THROUGH THE COASTAL CAROLINAS WED. OVERALL
EXPECT THE MAIN EFFECTS OF THIS TO BE SOME MID TO HIGH CLOUDS WED
INTO EARLY THURS AND A REINFORCING SHOT OF COOL AIR WITH A DEEP NW
FLOW SETTING UP THURS INTO THURS NIGHT. LIGHT NORTHERLY SFC FLOW
WILL BACK AROUND TO THE S-SW BRIEFLY WED AFTN AHEAD OF COLD FRONT
APPROACHING FROM THE NW. LOW TO MID LEVEL FLOW WILL REMAIN
WESTERLY THROUGH WED AND THEREFORE WILL NOT SEE MUCH IN THE WAY OF
MOISTURE RETURN INTO AREA. PCP WATER VALUES INCREASE UP TO A HALF
INCH WED AFTN INTO THE EVENING AS CLOUDS PASS THROUGH BUT NOT
EXPECTING ANY PCP. CLOUDS AND CAA THROUGH THE FIRST HALF OF WED
SHOULD KEEP TEMPS IN THE 50S MOST PLACES. MAY ACTUALLY SEE A
SLIGHT REBOUND WITH HIGHER READINGS IN THE LATER AFTN AS WINDS
BACK AROUND TO THE S-SW.

A DEEP NW FLOW DEVELOPS OVERNIGHT WED INTO THURSDAY WITH PLENTY OF
DRY AND COOL AIR MAKING ITS WAY INTO AREA. PCP WATER VALUES
DECREASE TO LESS THAN A QUARTER OF AN INCH BY THURS MORNING
AND REMAIN THIS LOW THROUGH THURS NIGHT. DEEP TROUGH OVER THE EAST
WILL PRODUCE A LOWERING OF H5 HEIGHTS AND LOW LEVEL THICKNESSES
AND 850 TEMPS PLUMMET HEADING INTO THURS. GFS SHOWS 850 TEMPS AS
LOW AS -9C BY THURS AFTN. THE WEATHER WILL FEEL LIKE MID WINTER
RATHER THAN THE FIRST DAYS OF SPRING. EXPECT A VERY DRY AND SUNNY
DAY ON THURS BUT TEMPS ONLY REACHING INTO THE 50S. OVERNIGHT LOWS
WILL BE IN THE 30S WED NIGHT WITH THE POSSIBILITY OF FROST. THURS
NIGHT WILL MOST LIKELY BE TOO DRY FOR ANY FROST BUT A FREEZE
WARNING WILL NOT BE OUT OF THE QUESTION AS TEMPS DROP INTO THE MID
20S. 

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...WEAK HIGH PRESSURE CONTINUES TO EXTEND DOWN
INTO THE CAROLINAS FROM CENTRAL CANADA AS A BROAD TROUGH OVER THE
NORTHEAST BEGINS TO LIFT OFF INTO THE ATLANTIC THROUGH THE
WEEKEND. MODELS SHOWING A DRIER START TO THE WEEKEND THAN
ORIGINALLY THOUGHT AS MID LEVEL RIDGE BUILDS UP FROM THE SOUTH FRI
INTO SATURDAY. SHALLOW COOL AIR WILL REMAIN IN PLACE AS LOW
PRESSURE DEVELOPS AND MOVES ACROSS THE SOUTHERN STATES. AN
INCREASING S TO SW LOW LEVEL FLOW WILL OVERRUN THIS COOL AIR IN
PLACE AND EXPECT POTENTIAL FOR LOW CLOUDS AND RAIN BUT NOW LOOKS
LIKE IT MAY BE DELAYED INTO THE LATTER PART OF THE WEEKEND. GFS
NOW SHOWS LOW PRESSURE DEVELOPING OVER TEXAS AND MOVING UP
THROUGH THE MISSISSIPPI VALLEY THROUGH THE WEEKEND. THIS WILL LIFT
A WARM FRONT NORTH. LOOKS LIKE WEDGE OF COOL AIR WILL RUN DOWN
THROUGH THE INLAND CAROLINAS WHILE A COASTAL TROUGH DEVELOPS BY
EARLY NEXT WEEK. THIS COASTAL TROUGH MAY DEEPEN INTO A LOW BY
MONDAY. THIS COULD ACT TO REINFORCE THE COOL NE FLOW ON THE BACK
END. AT THIS POINT MUCH UNCERTAINTY EXISTS AS TO THE EXACT
EVOLUTION OF THESE LOWS...BUT BASICALLY SPELLS OUT A PERIOD OF
UNSETTLED WEATHER THROUGH THE LATTER HALF OF THE WEEKEND INTO
EARLY NEXT WEEK. 

AS FOR TEMPERATURES...EXPECT READINGS WELL BELOW NORMAL WITH 50S
FOR HIGHS MOST DAYS AND 30S TO 40S FOR LOWS.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 12Z...WINDS HAVE SHIFTED TO THE WEST...HOWEVER LOW LEVEL 
MOISTURE WILL REMAIN UNTIL THE FRONT SWEEPS THROUGH...PROBABLY 
AROUND 14-15Z. IFR CEILINGS WILL LIFT TO MVFR BRIEFLY BEFORE 
SCATTERING BY LATE MORNING OR EARLY AFTERNOON. THE ATMOSPHERE 
BECOMES MODERATELY DRY AT ALL LEVELS BY AFTERNOON ALSO AS HIGH 
PRESSURE BUILDS IN WITH NORTHWEST FLOW. THIS FLOW WILL CONTINUE 
THOUGH THE OVERNIGHT HOURS WITH VFR CONDITIONS EXPECTED.

EXTENDED OUTLOOK...CHANCE OF RAIN LATE FRIDAY INTO SATURDAY... 
OTHERWISE VFR CONDITIONS SHOULD PREVAIL THROUGH THE EXTENDED PERIOD.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 6 AM TUESDAY...A COLD FRONT WILL SWEEP ACROSS THE WATERS 
14-16Z. IN THE WAKE OF THE FRONT...WINDS WILL SHIFT FROM SW TO W AND 
THEN TO THE NW THIS AFTERNOON. WINDS WILL CONTINUE TO VEER...TO N 
LATE TONIGHT AND TO NE BY MORNING AS HIGH PRESSURE RIDGES ACROSS THE 
AREA FROM THE W. IN THE IMMEDIATE WAKE OF THE FRONT...W WINDS MAY 
KICK UP BRIEFLY TO 15 TO 20 KT AS DRY AIR SURGES ACROSS THE WATERS. 
HOWEVER...THE STRONGEST WINDS ARE EXPECTED TONIGHT AS A NORTHERLY 
SURGE DEVELOPS. N TO NE WINDS WILL INCREASE TO NEAR 20 KT. SEAS... 
STILL CHURNED UP FROM THE OVERNIGHT CONVECTION...WILL BE SUBSIDING 
THIS MORNING...HELPED ALONG BY THE DEVELOPING OFFSHORE TRAJECTORIES.
HOWEVER...SEAS WILL BUILD OVERNIGHT WITH SOME 5 FT SEAS EXPECTED 
ACROSS THE OUTERMOST WATERS BY WED MORNING.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... 
AS OF 3 AM TUESDAY...COOL AND DRY HIGH PRESSURE WILL REMAIN IN
PLACE THROUGH MOST OF THE PERIOD. A DRY COLD FRONT WILL MOVE
THROUGH WED NIGHT. NORTHERLY WINDS UP AROUND 15 KTS EARLY WED WILL
BACK TO THE W-SW AND WEAKEN LATE WED AHEAD OF THIS FRONT. EXPECT A
SURGE IN WINDS AND SEAS ONCE COLD FRONT MOVES THROUGH WED NIGHT
INTO THURSDAY. WINDS WILL INCREASE UP TO 15 TO 20 KTS OVERNIGHT
WED. THE OFF SHORE WINDS WILL KEEP NEAR SHORE SEAS LOWER BUT OFF
SHORE SEAS WILL INCREASE FROM 2 TO 4 FT THROUGH WED UP TO 5 FT IN
OUTER WATERS BY THURS MORNING. WINDS AND SEAS WILL DECREASE
THROUGH THURS NIGHT INTO FRI. 

LONG TERM /FRIDAY THROUGH SATURDAY/... 
AS OF 3 AM TUESDAY...LIGHTER MORE VARIABLE WINDS WILL DEVELOP FRI
INTO SATURDAY AS WEAK HIGH PRESSURE REMAINS IN PLACE. A WEDGE OF
SHALLOW COOL AIR WILL REMAIN IN PLACE INLAND AS COASTAL TROUGH
DEVELOPS THROUGH THE WEEKEND. WINDS WILL THEREFORE REMAIN LIGHT
OUT OF THE NORTH AND BECOME MORE ONSHORE BY LATE IN THE WEEKEND AS
COASTAL TROUGH BECOMES MORE PRONOUNCED. FOR NOW WILL KEEP WITH
FAIRLY BENIGN MARINE CONDITIONS THROUGH MOST OF THE PERIOD BUT A
PINCHED GRADIENT WILL LEAD TO AN INCREASE IN E-NE WINDS LATE
SAT INTO SUNDAY WHICH COULD BRING WINDS UP TO 20 KTS BY SUNDAY
MORNING AND SEAS UP TO 3 TO 5 FT. 

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$

NEAR TERM...RJD
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...43