Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 050003
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
703 PM EST WED MAR 4 2015

.SYNOPSIS...
A COLD FRONT WITH A GOOD CHANCE OF RAIN AND SHARPLY COLDER
TEMPERATURES WILL MOVE ACROSS THE AREA TOMORROW AFTER ANOTHER
BALMY EVENING. THERE IS A CHANCE OF SOME LIGHT FROZEN PRECIPITATION IN
SOME AREAS EARLY FRIDAY BEFORE THE PRECIPITATION ENDS. THE WEEKEND
WILL FEATURE SLOWLY MODERATING TEMPERATURES. THE SLOW WARMUP WILL
CONTINUE NEXT WEEK WITH SHOWERS POSSIBLE.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 400 PM WEDNESDAY...AREAS OF DENSE FOG APT TO ENSHROUD OUR
COASTAL LAND ZONES AGAIN OVERNIGHT AS DAYTIME MIXING WANES AND
ONSHORE SEA WINDS BRING IN A CHILLED SATURATION. THIS MAY PUSH
INTO THE COASTAL INTERIOR BUT TAILING OFF TO PATCHY COVERAGE.

ROBUST NOCTURNAL WINDS AND HIGH DEWPOINTS WILL PROMOTE STRATUS
DEVELOPMENT LATE TONIGHT FARTHER INLAND...WITH WIDESPREAD MILD
CONDITIONS. AFTER AN INITIAL FALL TONIGHT OF TEMPERATURES WITH
LOSS OF DAY HEATING INTO THE LOWER AND MIDDLE 60S...HOURLY
TEMPERATURES WILL LEVEL OFF OVERNIGHT AT THESE VALUES...UPPER
50S BEACHES.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 400 PM WEDNESDAY...SPRING IS TYPICALLY A SEASON OF
EXTREMES...AND THURSDAY BY ITSELF WILL BE A MICROCOSM OF THE
SEASON AS A WHOLE. A VERY DYNAMIC SYSTEM AND ASSOCIATED COLD FRONT
WILL BRING VERY WARM TEMPS...VERY COLD TEMPS...CONVECTION...AND
EVEN WINTRY PRECIP. THE GRIDS REQUIRED USE OF BOTH SUMMER TIME
CONVECTIVE PROCEDURES...AND WINTER WEATHER PROCEDURES. IN OTHER
WORDS...IT IS NOT AN EASY FORECAST.

VERY WARM TEMPERATURES WILL START THURSDAY. HIGH PRESSURE OFF THE
COAST WILL CONTINUE TO PUMP WARM RETURN FLOW INTO THE AREA...AND
TEMPS WILL SOAR THE FIRST HALF OF THURSDAY. GUIDANCE CONTINUES TO
SLOW TIMING OF THE COLD FRONT...THANKS IN PART TO THE PERSISTENT
RIDGE AND THE DRAWN OUT/WEAKENING DRIVING VORTICITY IMPULSE. THIS
SUGGESTS THAT GUIDANCE MAY BE TOO COOL WITH HIGHS THURSDAY...AND
EXPECT MOST OF THE AREA TO AGAIN RISE TO 70 OR GREATER BY LATE
MORNING. SREF PLUMES SUGGEST TEMPS RISING AS HIGH AS THE MID 70S
LATE THURSDAY MORNING...AND PLAN TO HEDGE TOWARDS THE WARM END OF
THE SREF PLUME ENVELOPE THANKS TO A WARM START AND DELAYED FROPA.

THE COLD FRONT WILL CROSS THE REGION THURSDAY DURING THE LATE AFTN
THROUGH EARLY EVE...BUT MOST OF THE PRECIP ASSOCIATED WITH IT WILL
BE POST-FRONTAL. SPC HAS MOST OF THE AREA OUTLINED IN A "GENERAL
RISK" FOR SWODY2...MENTIONING POTENTIAL ELEVATED CONVECTION BEHIND
THE FRONT. FORECAST PROFILES DO SUGGEST A SMALL AMOUNT OF
INSTABILITY WITHIN THE 700-500MB LAYER...BUT THIS IS ACCOMPANIED BY
VERY WEAK MID-LEVEL FORCING AND ONLY MARGINAL JET-LEVEL DIFFLUENCE.
ADDITIONALLY...THE ATMOSPHERE ABOVE 700MB LOOKS TO REMAIN QUITE
DRY...SO DRIVING SATURATED PARCELS INTO THE CHARGE SEPARATION ZONE
WILL BE DIFFICULT TO ACHIEVE...AND THUS WILL CARRY JUST RW AND LEAVE
OUT ANY THUNDER MENTION THURSDAY EVE. WHAT WILL NOT BE DIFFICULT TO
ACHIEVE WILL BE RAPIDLY COOLING TEMPS...AS VERY STRONG CAA FOLLOWS
BEHIND THE COLD FRONT. TEMPS BETWEEN THURSDAY EVE AND FRIDAY MORNING
WILL DROP SOME 40 DEGREES ACROSS THE CWA...AND EXPECT THE ENTIRE CWA
TO DROP TO FREEZING OR BELOW FOR THURSDAY NIGHT MINS.

TEMPS BELOW FREEZING WILL BE ACCOMPANIED BY LIGHT...BUT STILL
OCCURRING PRECIP. THUS...FREEZING RAIN IS LOOKING MORE LIKELY LATE
THURSDAY NIGHT INTO FRIDAY. GUIDANCE DIFFERS INTO HOW LONG PRECIP
WILL PERSIST ON FRIDAY...BUT WITH THE VORT STRUNG OUT AND HANGING
WELL BACK TO THE WEST...COULD SEE PRECIP LINGER INTO FRIDAY
AFTN...ESPECIALLY ALONG THE COAST. WWD GRAPHICS PAINT A LARGE AREA
OF UP TO 0.10 ICE ACCRUAL...AND THIS SEEMS REASONABLE ATTM. COLD AIR
CHASING MOISTURE IS NEVER A GOOD SETUP FOR WINTRY PRECIP...BUT THE
STRENGTH AND RAPIDITY OF THE COLD AIR DROPPING SOUTH SHOULD OVERCOME
THE TYPICAL BIAS...AND FROZEN PRECIP IS EXPECTED FOR AT LEAST A
SHORT DURATION. FORTUNATELY...ANY ZR WILL BE FALLING ONTO WET AND
WARM GROUNDS SO ONLY ELEVATED SURFACES MAY ACTUALLY SEE
ACCUMULATION. THE HIGHEST ICE ACCRETION IS EXPECTED ALONG THE CAPE
FEAR AREA WHERE THE LONGEST CROSSOVER OF COLD TEMPS AND PRECIP IS
EXPECTED.

DRYING WILL OCCUR FRIDAY AFTN/EVE AS COLD HIGH PRESSURE RIDGES
EASTWARD...AND A CLEAR FRIDAY NIGHT IS EXPECTED WITH LIGHT NORTH
WINDS. WITH HIGHS FRIDAY AFTN EXPECTED TO BE ONLY IN THE LOW 30S
(!!)...MINS FRIDAY NIGHT SHOULD DROP WELL INTO THE 20S...AND MAY
APPROACH RECORD LOWS FOR THE DATE.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 400 PM WEDNESDAY...OVERALL THE MID LEVEL PATTERN FOR THE
EXTENDED HAS CHANGED LITTLE FROM THIS TIME YESTERDAY. STILL
EXPECTING CONSIDERABLE TROUGHING OVER THE EASTERN THIRD OF THE
CONUS. THROUGH EARLY TUESDAY WITH A RELAXING OF THE PATTERN
THEREAFTER. SOME DETAILS WITH SURFACE FEATURES HAVE CHANGED
HOWEVER.

ANY POPS WITH A GLANCING SHORTWAVE SYSTEM FOR SATURDAY HAVE BEEN
REMOVED. THE SYSTEM EMANATING FROM THE GULF OF MEXICO SHOULD OCCUR
SUNDAY AND SOME OF MEDIUM RANGE GUIDANCE IS NOW KEEPING ANY AFFECTS
WELL OFFSHORE. A MORE SIGNIFICANT SYSTEM WITH SLIGHTLY BETTER MODEL
AGREEMENT DEVELOPS LATE MONDAY AND TUESDAY. I HAVE MAINTAINED THE
SLIGHT CHANCE POPS FOR THIS TIME AND THE NEW DAY WEDNESDAY.
TEMPERATURE TRENDS REMAIN INTACT AS WELL WITH A DELIBERATE WARMING
TREND BASICALLY DUE TO AIRMASS MODIFICATION UNDER A VERY WEAK
PRESSURE PATTERN AFTER A COLD START SATURDAY.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 00Z...TERMINALS ARE CURRENTLY VFR BUT SEA FOG IS LOOMING FROM
JUST EAST OF KCRE TO SE OF KILM. IFR/LIFR/VLIFR IS POSSIBLE AT THE
COASTAL TERMINALS THIS EVENING. POTENTIALLY THE LOWEST CONDITIONS
THIS EVENING SHOULD BE AT KCRE WITH THE HIGHEST AT KILM/KMYR. KMYR
WOULD HAVE THE LEAST CHANCE OF SEA FOG OCCURRENCE. BY 06Z THROUGH
THE OVERNIGHT HOURS POTENTIAL FOR IFR/LIFR/VLIFR WILL BE THE HIGHEST
AT THE COASTAL TERMINALS. LOW STRATUS CIGS 300-500 FEET WILL BE
POSSIBLE AT KFLO/KLBT GENERALLY AFTER 08Z. LOW LEVEL WIND SHEAR IS A
GOOD POSSIBILITY WITH 30-40KT WINDS AROUND A 1K FOOT INVERSION.

IFR OR LOWER CIGS SHOULD BREAK UP 14-15Z WITH VFR EXPECTED...EXCEPT
MVFR AT KLBT. A STRONG COLD FRONT WILL MOVE THROUGH THE TERMINALS
DURING THE AFTERNOON WITH POST FRONTAL MVFR CIGS/-RA AT THE COASTAL
TERMINALS AND POST FRONTAL IFR/-RA AT THE INLAND TERMINALS.  WINDS
WILL SHIFT TO THE NORTH WITH GUSTS TO 18-25 KT.

EXTENDED OUTLOOK...IFR CONDITIONS ON THURSDAY...AND POSSIBLY INTO
FRIDAY ALONG THE COAST. OTHERWISE EXPECT VFR.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 400 PM WEDNESDAY...NOT A JOY RIDE TONIGHT WITH AREAS OF
DENSE MARINE FOG AND 10-20 KT SW WINDS...BUT NO ADVISORIES ARE
NEEDED. HIGHEST WINDS OFFSHORE...AND SEAS 3-4 INSHORE AND 4 TO
5 FT OUTER PORTION. SOME FRESH SWELL ENERGY IS KEEPING SEAS
SLIGHTLY ELEVATED FOR CORRESPONDING WINDS. SEA SPECTRUM A MIX OF
SSW WAVES 2-4 FT EVERY 4-5 SECONDS AND ESE WAVES 1-2 FEET EVERY
9-10 SECONDS. NO TSTMS BUT VSBYS AT TIMES LESS THAN 1/4 NM.


SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 400 PM WEDNESDAY...HIGH PRESSURE OFFSHORE AND A COLD FRONT
APPROACHING FROM THE WEST WILL KEEP A PINCHED GRADIENT WITH GUSTY SW
WINDS THE FIRST PART OF THURSDAY. WIND SPEEDS OF AROUND 15 KTS ARE
EXPECTED TO CONTINUE INTO THURSDAY AFTN BEFORE VEERING MORE TO THE
W/SW IN THE EVE. THIS WILL KEEP SEAS 3-5 FT...BUT WILL ALSO CONTINUE
THE POTENTIAL FOR AREA OF DENSE MARINE FOG AS THE WARM MOIST AIR
ADVECTS ACROSS STILL VERY COLD SHELF WATERS. HAVE OPTED NOT TO
EXTEND THE MARINE DFA ATTM...BUT A LOCAL EXTENSION INTO THURSDAY
AFTN MAY BE REQUIRED TONIGHT.

COLD FRONT APPROACHES AND THEN CROSSES THE WATERS FROM NORTH TO
SOUTH THURSDAY NIGHT. THIS IS A POWERFUL FRONT...AND WILL BE
ACCOMPANIED BY AN ABRUPT WIND SHIFT TO THE NORTH AND A QUICK RISE IN
SPEEDS TO 20-30 KTS FRIDAY MORNING. A GALE WATCH HAS BEEN ISSUED
BEGINNING AT 11PM THURSDAY NIGHT FOR FREQUENT GUSTS ABOVE GALE FORCE
DURING THIS TIME PERIOD...AND LASTING INTO LATE FRIDAY MORNING. HIGH
PRESSURE WILL BUILD EAST DURING FRIDAY AND FRIDAY
NIGHT...MAINTAINING THE NORTH WINDS BUT WITH SLOWLY DECREASING
SPEEDS. SEAS...WHICH WILL RISE TO AS HIGH 5-9 FT OVERNIGHT THURSDAY
INTO FRIDAY...WILL FALL THROUGH FRIDAY...BECOMING 2-4 FT AT THE END
OF THE PERIOD.


LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 400 PM WEDNESDAY...SOME RESIDUAL STRONGER WINDS CONTINUE ACROSS THE
WATERS EARLY SATURDAY WITH A NORTHERLY FLOW OF 10-15 KNOTS. AFTER
THIS A VERY WEAK AND PROLONGED PRESSURE PATTERN DEVELOPS UNDER A
RELAXING MID LEVEL PATTERN. DIFFICULT TO EVEN PINPOINT A PREDOMINANT
WIND DIRECTION BUT NORTHEAST BACKING TO WESTERLY SEEMS LIKE IT WILL
WORK. SPEEDS WILL BE TEN KNOTS OR LESS AND PROBABLY MUCH LESS IN
SOME CASES. SEAS WILL BE 2-4 FEET FOR A FEW HOURS SATURDAY THEN
SUBSIDE TO 1-2 FEET SUNDAY AND MONDAY.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...DENSE FOG ADVISORY UNTIL 6 AM EST THURSDAY FOR SCZ054-056.

NC...DENSE FOG ADVISORY UNTIL 6 AM EST THURSDAY FOR NCZ106-108-110.

MARINE...DENSE FOG ADVISORY UNTIL 6 AM EST THURSDAY FOR AMZ250-252-254-
     256.

     GALE WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING FOR
     AMZ250-252-254-256.

&&

$$
SYNOPSIS...SHK
NEAR TERM...MJC
SHORT TERM...JDW
LONG TERM...SHK
AVIATION...MRR








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