-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 261754
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1245 PM EST MON JAN 26 2015

.SYNOPSIS... A STRONG UPPER LEVEL DISTURBANCE WILL CROSS THE REGION
THIS AFTERNOON AND EVENING. HIGH PRESSURE WILL BUILD IN FROM THE
NORTHWEST TUESDAY THROUGH WEDNESDAY NIGHT. A CLIPPER LOW PRESSURE
SYSTEM WILL MOVE THROUGH THE AREA THURSDAY INTO EARLY FRIDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 1245 PM MONDAY...

...CHANCE OF RAIN SHOWERS THIS AFTERNOON...
...A BRIEF RAIN/SNOW SHOWER OR FLURRY POSSIBLE... MAINLY NE OF RDU
OVERNIGHT... NO WITH NO ACCUMULATION.

THE TEMPERATURES WERE ALREADY IN THE 40S THROUGHOUT CENTRAL NC THIS
MORNING AS LOW PRESSURE MOVES OVERHEAD... WITH EXPLOSIVE DEVELOPMENT
OFFSHORE THIS AFTERNOON AND TONIGHT. FOR OUR REGION... THIS WILL
OCCUR TOO FAR NORTH AND EAST TO HAVE ANY SIGNIFICANT IMPACTS.

THE MID/UPPER LEVEL ENERGY ASSOCIATED WITH THE CLIPPER SYSTEM WAS
ADVANCING EAST ACROSS THE REGION LATE THIS MORNING. H5 HEIGHT FALLS
WERE ON THE ORDER OF 120+ METERS FROM GA THROUGH THE CAROLINA`S.
THERE HAVE BEEN PLENTY OF QUICK MOVING RAIN SHOWERS WITH EVEN SOME
ISOLATED THUNDERSTORMS ASSOCIATED WITH THE STRONG LIFT OUT AHEAD OF
THE MID/UPPER LEVEL VORTICITY MAXIMUM NOTED OVER NORTHWEST NORTH
CAROLINA. THE MAIN TROUGH AXIS OVER THE MOUNTAINS WILL MOVE EAST
THIS AFTERNOON... AND AS IT DOES SO... THE MAIN AREA OF LIFT WILL
SHIFT TO OUR NE ZONES. EXPLOSIVE SURFACE DEVELOPMENT HAS BEGUN
OFFSHORE OF NC THIS MORNING WITH NUMEROUS CLUSTERS OF THUNDERSTORMS
IN THE GULF STREAM. THIS WAS OCCURRING AS THE ENERGY/LIFT FROM THE
NW TRANSFERS TO THE GULF STREAM AND WESTERN ATLANTIC.

WE WILL SHIFT THE LIKELY POP OUT OF THE REGION BY EARLY AFTERNOON
AND REPLACE WITH 20-30 POP FOR ADDITIONAL LIGHT RAIN SHOWERS. HIGHS
GENERALLY IN THE UPPER 40S NORTH RANGING INTO THE 50S SOUTH.

UPDATE TO TONIGHT... THERE IS STILL A FLEETING CHANCE OF BRIEF LIGHT
SNOW/RAIN SHOWERS... MAINLY OVER THE NE CORRIDOR OF NC THIS EVENING
AND OVERNIGHT. THIS WOULD ATTRIBUTED TO THE COLD DRY AIR SURGING IN
BEHIND THE DEPARTING STORM "CHASING THE MOISTURE". NO IMPACTS ARE
EXPECTED. IN FACT... LOWS MAY NOT FALL BELOW 32 REGARDLESS. -BADGETT

PREVIOUS DISCUSSION ISSUED AT 300 AM TODAY... INFRARED SATELLITE
SHOWS LOW PRESSURE ASSOCIATED WITH THE CLIPPER SYSTEM MOVING IN FROM
THE NORTHWEST OVER EASTERN KY AT THIS TIME. THIS SYSTEM WILL COMBINE
WITH SOUTHERN STREAM MOISTURE OFF OF THE SOUTHWEST ATLANTIC TO AND
RESULT IN A DEEPENING LOW PRESSURE SYSTEM THAT IS EXPECTED TO
STRENGTHEN CONSIDERABLY AS IT MOVES UP THE EASTERN SEABOARD MONDAY
INTO TUESDAY. CENTRAL NC WILL NOT HAVE TO DEAL WITH THE EXTENSIVE
PLUME OF MOISTURE OVER THE OCEAN SO THE WAVE...WHICH IS PROGGED TO
MOVE ACROSS NORTHERN SECTIONS OF THE THE CWA LATER TODAY WILL NOT
BRING MUCH PRECIPITATION WITH IT. WHAT IT DOES BRING WILL BE IN THE
FORM OF RAIN AS AND MAINLY ACROSS THE NORTHERN HALF OF THE CWA AS
TEMPERATURES RISE INTO THE UPPER 40S TO LOWER 50S ACROSS TEH SOUTH.
TIMING IS TRICKY AS IT LOOKS LIKE THERE COULD BE DIFFERENT PERIODS
OF RAIN AS SMALLER WAVE IMPULSES MOVE THROUGH THE AREA BRINING
POCKETS OF FAVORABLE DYNAMICS. THERMODYNAMICS WILL ALSO GET BETTER
AFTER 18Z AND MODELS HINT AT SOME INSTABILITY THROUGH 00Z WITH VERY
SKINNY...MOSTLY ELEVATED CAPE AND GOOD LAPSE RATES. THEREFORE CANNOT
RULE OUT AN ISOLATED THUNDERSTORM LATE THIS AFTERNOON.

AFTER 00Z THE LOW REALLY BEGINS TO DEEPEN OFF OF THE COAST AND THE
PRESSURE GRADIENT OVER CENTRAL NC WILL TIGHTEN UP CAUSING BREEZY
NORTHERLY WINDS WITH GUSTS OF 20-25 KTS POSSIBLE INTO THE OVERNIGHT
HOURS MONDAY NIGHT INTO TUESDAY MORNING. WITH BREEZY WINDS AND SOME
CLOUDS LINGERING IN THE EAST...RADIATIONAL COOLING PROSPECTS WILL
NOT BE AS GOOD AS BACK TO THE WEST WHERE BOTH WIND AND CLOUD COVER
SHOULD BE LESS. LOW TEMPERATURES WILL BOTTOM OUT IN THE UPPER 20S
WEST TO LOWER 30S IN THE EAST.
-- End Changed Discussion --

&&

.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 250 AM MONDAY...

BY TUESDAY MORNING...LOW PRESSURE OFF OF THE NEW ENGLAND COAST WILL
HAVE EVOLVED INTO A MATURE NOR`EASTER AND HAVE GROWN CONSIDERABLY IN
SIZE. CENTRAL NC WILL SET UP JUST ON THE WESTERN SIDE OF THE UPPER
LEVEL TROUGH AXIS WITH NORTHERLY WINDS AT THE SURFACE AND
NORTHWESTERLIES ALOFT. MODELS CURRENTLY SHOW VARYING DEGREES OF WRAP
AROUND MOISTURE STILL AFFECTING EASTERN PORTIONS OF THE CWA INTO
TUESDAY MORNING. WHILE IMPACTS OF THIS WILL BE MINUTE...IF
SATURATION UP THROUGH THE SNOW GROWTH ZONE HOLDS ON LONG
ENOUGH...THERE IS A CHANCE OF SEEING SOME SNOW FLURRIES OR A BRIEF
SNOW OR RAIN SHOWER ON TUESDAY MORNING. BEST CHANCES FOR THIS WILL
BE ACROSS THE NORTHEASTERN COUNTIES OF THE CWA. THIS VERY BRIEF
ACTIVITY COULD CONTINUE ON AND OFF THROUGH TUESDAY MORNING BEFORE
THE STORM EVENTUALLY MOVES FAR ENOUGH TO THE NORTHEAST TO PUT
CENTRAL NC IN THE COLD AND DRY SECTOR. THE EFFECT OF ALL THAT COLD
AIR ADVECTION WILL BE A MUCH COOLER DAY ON TUESDAY WITH HIGHS IN THE
LOW TO MID 40S NORTHEAST TO SOUTHWEST. COUPLE THAT WITH A BREEZY
NORTHERLY WIND IT WILL FEEL MORE LIKE THE UPPER 20S TO LOWER 30S
THAN IT WILL THE 40S. DRYING WILL CONTINUE INTO TUESDAY NIGHT WITH
DEWPOINTS FALLING INTO THE TEENS AND LOW TEMPERATURES IN THE MIDDLE
20S.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 210 AM MONDAY...

WED/WED NIGHT: QUIET WEATHER WITH MID LEVEL SHORTWAVE RIDGING
SHIFTING OVERHEAD AS HIGH PRESSURE RIDGING MOVES OVERHEAD. COLUMN IS
STABLE AND FAIRLY DRY WED... SO EXPECT PLENTY OF SUNSHINE. BELOW-
NORMAL THICKNESSES (BY 25-30 M) AND STATISTICAL GUIDANCE SUPPORT
COOL HIGHS OF 42-47. HIGH CLOUDS WILL INCREASE AND THICKEN WED
NIGHT... WITH A FLATTENING AND ACCELERATING WRLY FLOW ALOFT AND
INITIALLY WEAK MID LEVEL DPVA AHEAD OF A CLIPPER SHORTWAVE TROUGH
DIVING THROUGH THE UPPER MIDWEST. THESE HIGH CLOUDS MAY TAKE THE
EDGE OFF AN OTHERWISE GOOD NIGHT FOR RADIATIONAL COOLING... WITH
GENERALLY LIGHT WINDS AND LOW DEWPOINTS... BUT STILL EXPECT CHILLY
LOWS MOSTLY IN THE MID 20S.

THU/THU NIGHT: THIS WILL BE OUR NEXT CHANCE AT PRECIP... ALTHOUGH
SPECIFIC TIMING AND AMOUNTS ARE IN QUESTION AS GFS/ECMWF SOLUTIONS
DIVERGE. THE GREAT LAKES SHORTWAVE TROUGH WILL TRACK ESE THEN
EASTWARD ACROSS THE NORTHEAST/MIDATLANTIC STATES -- TRACKING THROUGH
THE BASE OF THE POLAR LOW OVER HUDSON BAY -- WHILE ITS CORRESPONDING
SURFACE LOW CROSSES THE OH VALLEY AND MIDATLANTIC COAST. GFS BUFR
SOUNDINGS SHOW CLOUD BASES STEADILY LOWERING THU MORNING AS LOW
LEVEL FLOW STRENGTHENS FROM THE WSW... PUSHING PW VALUES UP...
ALTHOUGH THEY PEAK AT JUST SLIGHTLY ABOVE-NORMAL VALUES... WITH A
LINGERING DRY SUBCLOUD LAYER OVER MUCH OF THE CWA. MOISTURE IS
DEEPEST AND MOST PRONOUNCED IN THE EASTERN PART OF THE FORECAST AREA
IN BOTH THE GFS AND ECMWF... HOWEVER THE ECMWF AND ITS DEEPER WAVE
GENERATES MORE QPF MUCH LATER (THU EVENING/NIGHT) COMPARED TO THE
LIGHTER/EARLIER GFS (BEST PRECIP CHANCES THU MORNING). WILL LEAN
TOWARD THE ECMWF... WHICH HAS DONE BETTER SHOWING DEEPER WAVES IN
RECENT WEEKS... BUT WILL KEEP POPS NO GREATER THAN 20-30% LATE THU
THROUGH THU NIGHT... FOCUSED ON THE EASTERN CWA. OVERALL MOISTURE
INFLUX DOES NOT APPEAR SUFFICIENT ENOUGH TO WARRANT ANYTHING MORE
THAN LIGHT QPF. SURFACE WET BULBS SHOULD BE INCHING ABOVE THE
FREEZING MARK BY THE TIME PRECIP BEGINS... AND THE LATER ARRIVAL
TIME SHOULD ENSURE THAT TEMPS THU NIGHT STAY MOSTLY ABOVE FREEZING.
EVEN SO... WE`RE LIKELY TO SEE DRYING ALOFT THU NIGHT AFTER THE MID
LEVEL TROUGH AXIS SWINGS THROUGH... WHICH WOULD LIMIT THE NON-LIQUID
PRECIP THREAT ANYWAY. TOTAL QPF SHOULD BE LIGHT... UNDER A QUARTER
INCH. HIGHS THU 47-52. LOWS THU NIGHT IN THE MID-UPPER 30S.

FRI-SUN: THE POLAR FRONT DROPS TO OUR SOUTH FRI... AND LOW LEVEL
THICKNESSES SLIP BACK TO AROUND 20 M BELOW NORMAL... YIELDING BELOW-
NORMAL HIGHS IN THE MID 40S TO LOWER 50S DESPITE FAIR SKIES AS COOL
HIGH PRESSURE BUILDS IN FROM THE NORTHWEST. LOWS FRI NIGHT IN THE
MID-UPPER 20S. UNCERTAINTY INCREASES FOR SAT/SUN AS THE GFS/ECMWF
SOLUTIONS CONTINUE TO DIVERGE IN IMPORTANT WAYS. BOTH HAVE A POLAR
LOW OVER HUDSON BAY/JAMES BAY AND ANOTHER LOW OVER NRN BAJA EARLY
SAT. THE GFS REMAINS FOCUSED ON THE POLAR STREAM... TAKING YET
ANOTHER CLIPPER WAVE THROUGH THE DAKOTAS AND MIDWEST THROUGH THE
NORTHEAST AND MIDATLANTIC THROUGH SUN... BRINGING ENHANCED
CLOUDINESS AND PERHAPS LIGHT PRECIP TO CENTRAL NC SAT (LIMITED BY
THE WEAK MOISTURE RETURN). THE ECMWF ON THE OTHER HAND IS MORE
FOCUSED ON THE SOUTHERN STREAM... EASING THE BAJA LOW SLIGHTLY
EASTWARD INTO NW MEXICO WITH SURFACE LOW PRESSURE FORMING IN THE NW
GULF... WHILE SRN STREAM ENERGY BEGINS TO SHEARS ENE TOWARD NC. THE
LATTER SOLUTION IS WARMER AND DRIER BUT STARTS TO BRING IN MOIST
OVERRUNNING FLOW BY LATE SUN. GIVEN THIS DISPARITY... PREFER JUST A
SMALL CHANCE POP ON SUN FOR NOW... WITH TEMPS REMAINING BELOW
NORMAL. -GIH

&&

.AVIATION /18Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
AS OF 1245 PM MONDAY...

LOW PRESSURE OVER THE REGION WILL TRANSFER OFFSHORE THIS AFTERNOON.
THIS STORM WILL LIFT UP THE NEW ENGLAND COAST TUESDAY.

MVFR CIGS AND VFR VSBYS ARE EXPECTED UNDER THE UPPER TROUGH THIS
AFTERNOON. MOST OF THE LIFT WILL BE WELL NE OF OUR REGION. YET...
WIDELY SCATTERED TO SCATTERED LIGHT RAIN SHOWERS ARE EXPECTED. VSBYS
SHOULD NOT BE LIMITED TO UNDER VFR IN THE LIGHT SHOWERS. NW WINDS 10-
15KT EXPECTED. MVFR CIGS SHOULD LINGER OVERNIGHT MAINLY IN THE NE
INCLUDING KRDU AND KRWI... WITH A POSSIBLE SPRINKLE OR FLURRY.

MVFR CIGS SHOULD LIFT TO VFR TUESDAY AS THE STORM TO OUR NE PULLS
AWAY.

LONG TERM: ONCE VFR CONDITIONS RETURN ON THE HEELS OF THIS
SYSTEM...THEY SHOULD REMAIN VFR UNTIL THE NEXT SYSTEM APPROACHES
FORM THE NORTHWEST ON THURSDAY NIGHT INTO FRIDAY WITH LIMITED
MOISTURE EXPECTED AGAIN.
-- End Changed Discussion --

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...ELLIS
LONG TERM...HARTFIELD
AVIATION...BADGETT