Area Forecast Discussion
Issued by NWS Wilmington, NC

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
934
FXUS62 KILM 142038
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
338 PM EST SUN FEB 14 2016

.SYNOPSIS...
ARCTIC AIR WILL BE SLOW TO ERODE THROUGH EARLY MONDAY AS IT GETS
OVERRUN WITH MOISTURE AS A LOW PRESSURE SYSTEM MAKES ITS WAY
NORTHEAST FROM THE LOWER MISSISSIPPI VALLEY. A FREEZING RAIN
ADVISORY IS IN EFFECT MIDNIGHT THROUGH NOON WITH MINIMAL AMOUNTS
OF ICE POSSIBLE WELL INLAND THROUGH EARLY MONDAY. A SOAKING RAIN
IS EXPECTED MONDAY NIGHT INTO EARLY TUESDAY AS THE LOW TRACKS
NORTHEAST OVER THE CAROLINAS INTO THE MID ATLANTIC. DRY WEATHER IS
EXPECTED FOR THE REMAINDER OF THE WEEK WITH UNSEASONABLY WARM
WEATHER FOR NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM SUNDAY...TRICKY FORECAST COMING UP TONIGHT WITH
POTENTIAL FOR FREEZING RAIN ACROSS INLAND AREAS LATE TONIGHT.
ARCTIC HIGH WILL GRADUALLY RETREAT NORTHEAST THIS AFTERNOON AND
OVERNIGHT AS MID LEVEL RETURN FLOW BACKS TO SOUTHWEST. ALTHOUGH
ITS INFLUENCE WILL BE WEAKENING THE ARCTIC HIGH WILL STILL BE
WEDGING DOWN THE COAST AS ANTICIPATED COASTAL TROUGH STARTS TO
DEVELOP. AS IS ALWAYS THE CASE WITH THE MARGINAL WINTER WEATHER
EVENTS IN THE COASTAL CAROLINAS TIMING WILL BE KEY TO WHAT...IF
ANY...AREAS END UP WITH FREEZING RAIN. SURFACE AIRMASS AWAY FROM
THE COAST WILL BE AT OR BELOW FREEZING. COLD AIR WILL BE IN THE
PROCESS OF RETREATING BUT THE WARM AIR NEVER MOVES IN AS QUICKLY
AS THE GUIDANCE DEPICTS.

FORECAST SOUNDINGS ALL BUT ENSURE PRECIP TYPE WILL BE LIQUID WITH
BOTH THE GFS AND NAM FORECAST SOUNDINGS SHOWING A DEEP WARM NOSE
THAT IS SOME 10 DEGREES ABOVE FREEZING. ABOVE 8K FT THE AIR IS
DRY...WHICH WILL KEEP PRECIP LIGHT...EITHER IN THE FORM OF DRIZZLE
OR LIGHT RAIN. HOWEVER...BY 09Z OR SO THE LAYERS BELOW 8K FT ARE
NEARLY SATURATED...EXCEPT FOR THE LOWEST 500 FT. IT IS WITHIN THIS
LAYER THAT ISENTROPIC LIFT...ALONG 280K AND 285K SURFACES...WILL
BE STRONGEST AND SHOULD BE SUFFICIENT TO PRODUCE LIGHT RAIN. IN
ADDITION TO THE STUBBORNNESS OF THE COLD AIR LIGHT RAIN/DRIZZLE
FALLING INTO VERY DRY SURFACE AIR WILL HELP REINFORCE THE LOW
LEVEL COLD POOL VIA EVAPORATIVE COOLING. THIS ALL BOILS DOWN TO
POTENTIAL FOR A TRACE TO A HUNDREDTH OR TWO OF ICING ACROSS FAR
WESTERN AND NORTHWESTERN COUNTIES. DO NOT THINK THERE WILL BE
WIDESPREAD COVERAGE OF ICE INSTEAD IT WILL BE MUCH MORE ISOLATED
IN NATURE. A FREEZING RAIN ADVISORY WILL BE ISSUED WITH THE
AFTERNOON MAIN PACKAGE.

MEANWHILE ALONG THE COAST A SURFACE TROUGH WILL DEVELOP AS THE
HIGH RETREATS. THE TROUGH WILL SLOWLY MOVE ONSHORE VERY LATE
TONIGHT...INCREASING PRECIP CHANCES ALONG THE COAST. TEMPERATURES
HERE WILL BE TOO WARM FOR PRECIP TYPE ISSUES AND RAIN IS
EXPECTED...THOUGH SOME OF IT MAY HAVE SOME CONVECTIVE TRAITS.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...WHAT SEEMS TO BE A NEVER-ENDING PARADE OF
COMPLEX FORECASTS CONTINUES WITH THIS SHORT TERM PERIOD AS A STRONG
STORM SYSTEM WILL CREATE A VARIETY OF WEATHER IMPACTS...FROM A
WINTRY MIX MONDAY MORNING TO POTENTIAL SEVERE WEATHER MONDAY NIGHT
INTO TUESDAY...ALONG WITH A LARGE VARIATION IN TEMPERATURES. WILL
TRY TO SORT OUT THE DETAILS HERE:

AN EXTREMELY COLD AIR MASS WILL REMAIN IN PLACE MONDAY MORNING
THANKS TO AN ARCTIC HIGH PRESSURE CENTERED OVER NEW ENGLAND. THIS
HIGH WILL SLOWLY RETREAT TO THE EAST THROUGH MONDAY...BUT MAINTAIN A
WEAK WEDGE INTO THE CAROLINAS THROUGH THE AFTN. AS THIS OCCURS...AN
AMPLIFYING TROUGH WHICH WILL BE THE IMPETUS FOR CYCLOGENESIS
TUESDAY...WILL DIG INTO THE MS VLY TO DRIVE STRENGTHENING SW FLOW ATOP
THE WEDGE MONDAY. THIS OF COURSE IS AN ISENTROPIC LIFT
SCENARIO...AND GUIDANCE DEPICTS INCREASING LIFT ON THE 280K AND 285K
SURFACES BEGINNING JUST BEFORE THIS PERIOD. AT THE SAME TIME...A
SHARPENING COASTAL TROUGH WILL BEGIN TO PUSH ONSHORE AS SURFACE FLOW
BECOMES INCREASING SE AROUND THE DEPARTING HIGH PRESSURE TO THE
NORTH. GUIDANCE DIFFERS WIDELY IN WHICH PRECIP MECHANISM WILL BE
MORE PRONOUNCED...BUT THERE SHOULD BE AT LEAST 2 DIFFERENT PRECIP
REGIMES MONDAY MORNING - STRATIFORM WITHIN THE ISENTROPIC LIFT
ACROSS THE NW TIER...AND MORE CONVECTIVE EMBEDDED ALONG THE COASTAL
FRONT LIFTING TO THE NW. THE HEAVIER PRECIP IS EXPECTED ALONG THE
COASTAL FRONT...FORTUNATELY THIS REGION WILL TOO WARM FOR ANY PTYPE
CONCERNS. THE QUESTION THEN REMAINS HOW SIGNIFICANT WILL BE THE
FREEZING PRECIP TO THE NW.

INITIALLY...THE COLUMN SATURATES BENEATH 800MB BUT REMAINS DRY IN
THE MID LEVELS. THIS SUPPORTS ONLY VERY LIGHT STRATIFORM PRECIP. THE
WARM NOSE INITIALLY IS ONLY SLIGHTLY ABOVE ZERO...BUT BY NOON WARMS
TO TO +9C OR SO...SO NO SNOW IS POSSIBLE...AND ZR WILL BE THE
PRIMARY CHARACTERISTIC...BECOMING ALL RAIN BY NOON. OVERALL LIFT IS
WEAK SO TOTAL QPF WILL BE LIGHT...BUT IT ONLY TAKES A TRACE OF ZR TO
REQUIRE AN ADVISORY. FREEZING RAIN ADVISORIES HAVE BEEN RAISED
THROUGH NOON FOR 5 COUNTIES IN THE FAR NW TIER...AND AFTER THAT TIME
TEMPERATURES WILL WARM TO ABOVE FREEZING AND ALL PRECIP WILL BECOME
LIQUID.

THERE MAY BE A BREAK IN PRECIP MONDAY AFTN/EVE BEFORE A PRE-FRONTAL
TROUGH AHEAD OF THE COLD FRONT RACES ACROSS THE CWA. THIS WILL BRING
THE HEAVIEST QPF...AS INSTABILITY INCREASES IN WHAT WILL MATERIALIZE
AS AN INCREASING WARM SECTOR. SBCAPE REMAINS PRETTY LOW DUE TO WEAK
LAPSE RATES AND TIME OF DAY (PEAKING AT 200-300 J/KG)...BUT MUCAPE
DUE TO ELEVATED INSTABILITY MAY BE QUITE A BIT HIGHER. LOW LEVEL
WIND FIELDS INCREASE DRAMATICALLY AS EVIDENCED BY 0-6KM SHEAR
APPROACHING 50 KTS AND 0-3KM HELICITY OF 200-300 M2/S2. PWATS CLIMB
TOWARDS 1.25 INCHES...AND THIS SUGGESTS A PERIOD OF HEAVY RAINFALL
WITH A NON-ZERO DAMAGING WIND THREAT. SPC MAINTAINS A MRGL RISK FOR
THE END OF THE SWODY2 INTO SWODY3 AS THIS BOUNDARY CROSSES THE AREA.
OVERALL RISK IS MINIMAL BUT WITH SUCH STRONG LOW LEVEL WIND FIELDS
IT WILL NOT TAKE TOO MUCH OF A CONVECTIVE SHOWER TO PRODUCE SURFACE
WIND GUSTS. IT MAY BE A "SEVERE SHOWERS" TYPE SETUP WITH VERY
LIMITED LIGHTNING.

WITH THE TROUGH REMAINING WEEK AND POSITIVE TO NEUTRAL...PRECIP WILL
RACE TO THE EAST BY TUESDAY MORNING...WITH DRYING OCCURRING AND
TUESDAY WILL LIKELY BE A WARM AND SUNNY DAY. NO COLD ADVECTION UNTIL
LATE IN THE PERIOD..AND THE SUNSHINE COMBINED WITH HIGH THICKNESSES
AND 850MB TEMPS AROUND 7C SUPPORTS HIGHS WELL INTO THE
60S...ESPECIALLY ALONG THE COAST...COOLER WELL INLAND. COLD
ADVECTION WILL FINALLY SETTLE INTO THE REGION AS A DRY COLD FRONT
CROSSES OFFSHORE LATE IN THE PERIOD.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 PM SUNDAY...MAIN MID TO UPPER TROUGH WILL SHIFT EAST AND
LIFT OFF TO THE NORTHEAST THROUGH TUESDAY AS HIGH PRESSURE BUILDS IN
AT THE SURFACE. WINDS WILL VEER THROUGH THE DAY WITH A DEEP WESTERLY
FLOW SHIFTING AROUND TO N-NW WED NIGHT INTO THURS. OVERALL THERE
WILL BE CAA BRINGING 850 TEMPS FROM CLOSE TO 5C WED MORNING DOWN TO
ALMOST -2C BY THURS MORNING. THEREFORE EXPECT TEMPS TO TAKE A DIP
THROUGH MID WEEK WITH NEAR NORMAL READINGS ON WED BECOMING BELOW
NORMAL FOR THURS. WILL KEEP TEMPS IN THE LOWER TO MID 50S FOR THURS

WILL KEEP SOME CLOUDS IN THE FORECAST FOR WED AS LAST BIT OF
SHORTWAVE ENERGY RIDES THROUGH BUT EXPECT PLENTY OF SUNSHINE THURS
AND FRI AS HIGH PRESSURE SETTLES OVER THE SOUTHEAST AND RIDGE BUILDS
ALOFT. HEIGHT RISES WILL PRODUCE A STEADY RISE IN 850 TEMPS THROUGH
LATE THURS INTO FRI. THEREFORE EXPECT TEMPS TO RECOVER TO NORMAL AND
THEN ABOVE NORMAL OVER THE WEEKEND WITH A DEEP SW TO W FLOW
DEVELOPING. THERE WILL BE AN INCREASE IN MID TO UPPER LEVEL MOISTURE
AND THEREFORE CLOUDS OVER THE WEEKEND...ESPECIALLY AS WEAK LOW
PRESSURE DEVELOPS TO THE WEST ON SUNDAY BRINGING INCREASING RAIN
CHANCES HEADING INTO MONDAY.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 18Z...QUITE A BIT OF UNCERTAINTY ON THE BACK END OF THIS
FORECAST WITH RESPECT TO TIMING AND INTENSITY OF THE PRECIP AS
WELL AS PRECIP TYPE. INCREASING HIGH CLOUDS THIS AFTERNOON IN
ADVANCE OF THE NEXT SYSTEM. NORTHEAST FLOW IS EXPECTED THROUGH THE
EVENING HOURS. OVERNIGHT...LIGHT PRECIP WILL BEGIN TO FORM AS
ISENTROPIC LIFT BEGINS. MODELS DO NOT SHOW MUCH MID LEVEL MOISTURE
SO THINK PRECIP WILL BE QUITE LIGHT. MOISTURE PROFILES SHOW A LOT
OF WARM AIR ADVECTING IN JUST ABOVE THE SURFACE...HOWEVER SURFACE
TEMPERATURES AT THE INLAND TERMINALS WILL LIKELY BE BELOW FREEZING
AT THE ONSET...SO LIGHT FREEZING RAIN IS EXPECTED...EMPHASIS ON
LIGHT. ALONG THE COAST...A PRETTY GOOD COASTAL TROUGH IS EXPECTED
WITH RAIN BEGINNING AFTER DAYBREAK. THE INLAND TERMINALS WILL BE
IN THE WEDGE ALL DAY...HOWEVER TEMPS ARE EXPECTED TO RISE ABOVE
FREEZING AROUND MID MORNING...SO TRANSITION TO ALL RAIN.

EXTENDED OUTLOOK...POSSIBLE MVFR/IFR CONDITIONS IN RAIN/SHOWERS
MONDAY AFTERNOON THROUGH TUESDAY MORNING. BECOMING VFR TUESDAY
AFTERNOON THROUGH FRIDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM SUNDAY...RETREATING ARCTIC HIGH WILL MAINTAIN
NORTHEAST FLOW INTO THE EVENING WITH WIND SPEEDS SLOWLY DECREASING
AS GRADIENT RELAXES. DEVELOPMENT OF THE COASTAL TROUGH THIS
EVENING AND OVERNIGHT WILL HELP FURTHER WEAKEN THE GRADIENT WITH
WIND SPEEDS DROPPING NEAR 10 KT AROUND MIDNIGHT. THE TROUGH STARTS
MOVING TO THE COAST AFTER MIDNIGHT WITH EAST TO SOUTHEAST WINDS
DEVELOPING OVER THE WATERS. GRADIENT ON THE EAST SIDE OF THE
TROUGH BECOMES MORE DEFINED AND SPEEDS FOLLOW AN UPWARD
TREND...RETURNING TO THE 15 TO 20 KT RANGE LATE IN THE PERIOD.
SEAS 2 TO 4 FT THIS AFTERNOON WILL DROP TO 2 TO 3 FT OVERNIGHT.
INCREASED ONSHORE FLOW LATE IN THE PERIOD WILL PUSH SEAS BACK INTO
THE 2 TO 4 FT RANGE LATE IN THE PERIOD.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...SMALL CRAFT ADVISORY RAISED FOR ALL WATERS
BEGINNING AT 7AM MONDAY.

HIGH PRESSURE RETREATING SLOWLY OFF THE NEW ENGLAND COAST WILL
COMBINE WITH A STRONG LOW PRESSURE APPROACHING FROM THE WEST TO
PINCH THE GRADIENT AND DRIVE INCREASING SOUTHERLY WINDS MONDAY.
INITIALLY...WINDS WILL BE SE AT 10-15 KTS BUT STEADILY INCREASING
THROUGH THE DAY TO 15-25 KTS AS A COASTAL TROUGH MOVES INLAND AND A
PRE FRONTAL TROUGH/COLD FRONT LIFTS NORTH LATE. BEHIND THIS SECOND
FEATURE...WINDS WILL VEER TO THE SW AND INCREASE EVEN
FURTHER...POTENTIALLY GUSTING TO GALE FORCE VERY LATE MONDAY NIGHT
INTO TUESDAY BEFORE SLOWLY EASING AND BECOMING MORE WESTERLY LATE
TUESDAY AFTER A SECOND FRONTAL PASSAGE. SCA IS IN EFFECT THROUGH 6AM
TUESDAY FOR NOW...AT WHICH POINT IT WILL LIKELY EITHER BE EXTENDED
OR POTENTIALLY UPGRADED TO A GALE. SEAS WILL RISE SHARPLY MONDAY
FROM 3-5 FT TO AS MUCH AS 6-10 FT LATE...BEFORE SLOWLY FALLING
THROUGH TUESDAY BUT REMAINING ABOVE SCA THRESHOLDS.

LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 300 PM SUNDAY...WESTERLY FLOW WILL BEGIN TO VEER AROUND TO THE
NW TO N THROUGH WED INTO EARLY THURS AS HIGH PRESSURE BUILDS IN.
WINDS DROPPING DOWN TO 10 TO 15 KTS ON WED WILL INCREASE SLIGHTLY IN
STRENGTH AS THEY BECOME MORE NORTHERLY OVERNIGHT WED INTO EARLY
THURS.  SEAS DIMINISHING THROUGH WED WILL DROP BELOW SCA THRESHOLDS
BY AFTN AND WILL REMAIN IN THE 2 TO 4 FT RANGE THROUGH THURS
DROPPING OFF FURTHER DOWN TO 3 FT OR LESS THROUGH EARLY FRI. BY FRI
AFTN HIGH PRESSURE SHIFTS OFF SHORE AND A S-SW RETURN FLOW DEVELOPS
WHICH WILL LEAD TO A SLIGHT RISE IN SEAS UP TO 3 TO 5 FT BY EARLY
SATURDAY.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...FREEZING RAIN ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM EST
     MONDAY FOR SCZ017-023-024.
NC...FREEZING RAIN ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM EST
     MONDAY FOR NCZ087-096.
     COASTAL FLOOD ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
     NCZ107.
MARINE...SMALL CRAFT ADVISORY FROM 7 AM MONDAY TO 6 AM EST TUESDAY FOR
     AMZ250-252-254-256.

&&

$$

NEAR TERM...III
SHORT TERM...JDW
LONG TERM...RGZ
AVIATION...DL



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.