083
FXUS62 KILM 220717
AFDILM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
317 AM EDT MON OCT 22 2018
SYNOPSIS
HIGH PRESSURE WILL MOVE OFF THE NORTH CAROLINA COAST TODAY. A
SECOND CANADIAN HIGH WILL BUILD INTO THE GREAT LAKES LATE
TUESDAY, PUSHING ANOTHER COLD FRONT THROUGH THE AREA. LOW
PRESSURE WILL DEVELOP ALONG THE GULF COAST THURSDAY, BRINGING
GOOD RAIN CHANCES TO THE CAROLINAS FRIDAY INTO EARLY SATURDAY.
NEAR TERM /THROUGH TONIGHT/
AS OF 300 AM MONDAY...COLD ADVECTION SHUTTING OFF AND ACTUALLY SLATED
TO REVERSE SHORTLY. WITH HIGH PRESSURE STILL NEARBY AND BRINGING A
LIGHT NE TO VARIABLE WIND HOWEVER MIXING WILL REMAIN QUITE SHALLOW
AND HEATING UP ALL THE WAY TO CLIMATOLOGY (SOME 30 DEGREES ABOVE
PREDAWN LOWS) WILL BE TOO TALL AN ORDER. MOST PLACES WILL GET CLOSE
HOWEVER; HIGHS IN THE UPPER 60S WILL BE GENERALLY 5 DEGREES BELOW
SEASONABLE NORMS. THE WARM ADVECTION WILL ON THE OTHER HAND PREVENT
A REPEAT OF THIS MORNING'S CHILL; WITH AREAS GENERALLY REMAINING IN
THE MID 40S TO LOW 50S ALONG THE COAST.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
AS OF 300 AM MONDAY...AN UPPER LEVEL TROUGH ACROSS SE CANADA AND
A RIDGE BUILDING ACROSS THE PLAINS STATES WILL MAINTAIN A
NORTHWESTERLY 500 MB FLOW OVER THE CAROLINAS. AT THE SURFACE,
HIGH PRESSURE SUPPORTED BY THE UPPER RIDGE WILL BUILD ACROSS THE
WESTERN GREAT LAKES, PUSHING A COLD FRONT SOUTHWARD THROUGH THE
CAROLINAS TUESDAY EVENING. MOISTURE RETURN AHEAD OF THIS FRONT
SHOULD BE MEAGER AND QUITE SHALLOW. IT IS REMINISCENT TO THE
SYSTEM THAT PASSED THROUGH HERE LAST SATURDAY WHERE SCATTERED
LIGHT SHOWERS REMAINED OFFSHORE. I'LL MAINTAIN A FORECAST OF
CONSIDERABLE CLOUDS TUESDAY BUT WITH DRY CONDITIONS CONTINUING
INLAND FROM THE BEACHES.
GFS/ECMWF WERE FOLLOWED CLOSELY FOR TEMPERATURES THROUGH THE
PERIOD. HIGHS LOWER TO MID 70S TUESDAY WILL COOL INTO THE UPPER
60S WEDNESDAY. LOWS AROUND 50 TUESDAY NIGHT SHOULD FALL INTO THE
MID 40S WEDNESDAY NIGHT. THOSE WEDNESDAY NIGHT LOWS ARE A LITTLE
UNCERTAIN AS MOST MODELS SHOW DENSE CIRRUS STREAMING THROUGH THE
UPPER RIDGE FROM THE REMNANTS OF PACIFIC HURRICANE WILLA AS IT
STREAKS EASTWARD ALONG THE GULF COAST. HOW MUCH IMPACT THIS WILL
HAVE ON RADIATIONAL COOLING IS UNCERTAIN.
LONG TERM /THURSDAY THROUGH SUNDAY/
AS OF 300 PM FRIDAY...CANADIAN HIGH PRESSURE WILL BUILD DOWN
INTO THE CAROLINAS THROUGH MID WEEK. THIS WILL PRODUCE BELOW
NORMAL TEMPS WITH ANOTHER SURGE OF COLD AIR AND DRY AIR. TEMPS
BOTH WED NIGHT AND THURS NIGHT WILL BE DOWN NEAR 40, EXCEPT
WARMER RIGHT ALONG THE COAST. TEMPS WILL REMAIN IN THE 60S FOR
MAX TEMPS THROUGH MUCH OF THE LONG TERM PERIOD.
BY FRIDAY, LOW PRESSURE MOVING UP FROM THE GULF COAST WILL BEGIN
TO SPREAD CLOUDS AND RAIN NORTHWARD. IF CLOUDS MOVE IN EARLIER
ON FRI, COULD END UP BEING COOLER WITH TEMPS POSSIBLY NOT EVEN
MAKING IT TO 60 DEGREES IN PLACES, BUT OVERALL EXPECT A CLOUDY,
COOL AND RAINY WEATHER TO DEVELOP FRI AND SAT AS LOW PRESSURE
DEEPENS AS IT MOVES UP THE SOUTHEAST COAST. THE SHALLOW COOL
DENSE AIR WILL BE OVERRUN WITH THE WARMER MOISTER AIR TO
PRODUCE LOW CLOUDS AND RAIN ACROSS MUCH OF THE FORECAST AREA.
SOME WARMER AIR MAY REACH COASTAL AREAS IN A MORE EASTERLY FETCH
ON THE TOP SIDE OF THE LOW IF IT MOVES CLOSE ENOUGH. BUT MOST
PLACES SHOULD REMAIN IN THE COOLER NORTHERLY FLOW ON BACK END,
LEAVING ANY CONVECTION CONFINED TO MAINLY OFF THE COAST. MAY SEE
SOME DRYING ON THE BACK END BY THE END OF THE WEEKEND, BUT ITS
TOO FAR OUT TO SAY WITH ANY CERTAINTY. IT WILL DEPEND ON HOW THE
MID TO UPPER LOW DIVING DOWN FROM THE UPPER MIDWEST EVOLVES
OVER TIME. LOOKS LIKE A FAIRLY SATURATED COLUMN LATE FRI THROUGH
SATURDAY WITH CLOUDS AND RAIN A LIKELY SCENARIO.
AVIATION /06Z MONDAY THROUGH FRIDAY/
AS OF 06Z...VFR WITH CLEAR SKIES. LIGHT N TO NE WINDS WILL BECOME
LIGHT AND VARIABLE AS HIGH PRESSURE JUST NORTH OF THE REGION EXTENDS
A RIDGE AXIS OVERHEAD.
EXTENDED OUTLOOK...VFR MON/WED/THU. CHANCE OF MVFR CIGS/ISOLATED
SHOWERS TUE AT THE COASTAL TERMINALS, MOST LIKELY KMYR, AS A WEAK
COLD FRONT MOVES THROUGH. MVFR/IFR/RA/WINDY FRI AS LOW PRESSURE
MOVES UP THE COAST.
MARINE
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM MONDAY...WINDS HAVE DROPPED OFF AND WILL REMAIN
LIGHT AS HIGH PRESSURE BOTH PASSES BY TO THE NORTH AND EXTENDS A
RIDGE AXIS OVERHEAD. SEAS AS ALWAYS WILL BE SLOWER TO ABATE;
THOUGH THE RELAXATION HAS ALREADY DROPPED SIG WAVE HEIGHT TO
3.5FT ALL THE WAY OUT TO 41013. BY LATER TODAY BOTH WIND AND
SEAS WILL DROP TO ALMOST MINIMAL VALUES; 10KT OR LESS AND
GENERALLY 2 FT OR LESS.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM MONDAY...A COLD FRONT WILL MOVE ACROSS THE COASTAL
WATERS TUESDAY EVENING AS HIGH PRESSURE BUILDS INTO THE WESTERN
GREAT LAKES. NORTHEASTERLY WINDS WILL INCREASE TO 15-20 KT
WEDNESDAY BEHIND THE FRONT, WITH SEAS BUILDING TO A SOLID 4 FEET
WITH A CHANCE OF 5-FOOTERS 15-20 MILES FROM SHORE.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 300 PM SUNDAY...COOL CANADIAN HIGH PRESSURE WILL BUILD
DOWN OVER THE WATERS THROUGH MID WEEK. THIS NORTHERLY SURGE WILL
WILL PRODUCE AN INCREASE IN WINDS AND SEAS WED INTO THURS. THE
COLD AIR RUSHING OVER THE WARMER WATERS WILL KEEP THE MARINE
LAYER WELL MIXED WITH GUSTY NORTHERLY WINDS WED NIGHT THROUGH
THURS NIGHT. WINDS AND SEAS MAY REACH INTO SCA THRESHOLDS WED
NIGHT INTO EARLY THURS, AS NE WINDS MAY INCREASE UP TO 15 TO 25
KTS AND SEAS REACH ABOVE 6FT.
BY FRIDAY, LOW PRESSURE WILL BEGIN TO MOVE UP FROM THE GULF
COAST. MODELS SHOW THIS LOW DEEPENING AS IT TRACKS UP ALONG OR
JUST OFF THE COAST. THE DEEPENING LOW SHOULD PRODUCE A
TIGHTENED GRADIENT FLOW ACROSS THE SOUTHEAST COASTAL WATERS.
EXPECT STRONG NE WINDS, BUT NEED TO SEE EXACTLY HOW THE LOW
EVOLVES BEFORE WE SAY WITH ANY CERTAINTY.
ILM WATCHES/WARNINGS/ADVISORIES
SC...NONE.
NC...NONE.
MARINE...NONE.
SYNOPSIS...TRA
NEAR TERM...MBB
SHORT TERM...TRA
LONG TERM...RGZ
AVIATION...MBB
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page