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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 010305
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1005 PM EST SAT JAN 31 2015

.SYNOPSIS...ARCTIC HIGH PRESSURE OVER THE CAROLINAS WILL SHIFT WILL
SHIFT OFFSHORE THROUGH EARLY SUNDAY. A COLD FRONT WILL TRACK EAST
ACROSS THE REGION SUNDAY NIGHT AND EARLY MONDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 957 PM SATURDAY...

MID LEVEL CLOUDINESS CONTINUED TO OVERSPREAD WESTERN NORTH CAROLINA
THIS EVENING. THE TEMPERATURES WERE ALREADY IN THE 20S IN THE
NORTHEAST BUT RANGED INTO THE 40S IN THE SW... WHERE THE MID LEVEL
CLOUDS HAD REACHED. BASED ON SATELLITE AND OBSERVATIONS IT APPEARS
THAT THE MID LEVEL CLOUDS WILL REACH INTO THE TRIAD BY AROUND
MIDNIGHT... THEN REACH EASTERN SECTIONS BEFORE 300 AM. THIS INCREASE
IN THE MID LEVEL CLOUD DECK WILL HAVE A SIGNIFICANT IMPACT ON
TEMPERATURES. THE TEMPERATURES IN THE WESTERN PIEDMONT SHOULD BOTTOM
OUT AROUND OR BEFORE MIDNIGHT (UPPER 20S TO MID 30S). TEMPERATURES
IN THE NE ZONES (THE LAST TO SEE THE THICKER MID LEVEL CLOUD DECK)
WILL BOTTOM OUT AROUND 100 AM TO 300 AM (MID TO UPPER 20S)... THE
RISE A BIT BY 12Z. WINDS WILL BE LIGHT AND MAINLY FROM THE SW
OVERNIGHT.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...
AS OF 330 PM SATURDAY...

WITH HIGH PRESSURE OFFSHORE SUNDAY MORNING...SOUTHERLY FLOW WILL
ALLOW ADDITIONAL MODERATION AS THICKNESSES CLIMB BACK TOWARD 1320M
WHICH IS 5-10 ABOVE NORMAL.  MID AND HIGH CLOUDS WILL CONTINUE TO
BLANKET THE REGION...BUT EXPECT THE SOUTHERLY WIND TO OVERCOME SOME
OF THE LOSS OF HEATING...SO WILL KEEP TEMPS IN LINE WITH STATISTICAL
GUIDANCE IN THE MID TO UPPER 50S AND MAYBE TOUCHING 60 IN THE SOUTH.

MEANWHILE...A SURFACE LOW WILL DEVELOP IN RESPONSE TO THE UPPER
TROUGH DIGGING THROUGH THE CENTRAL PLAINS AND MID-MISSISSIPPI
VALLEY...MOVING ACROSS THE CENTRAL APPALACHIANS SUNDAY NIGHT.
MODELS ARE IN PRETTY GOOD AGREEMENT ON PRECIP ARRIVING IN THE
WESTERN PIEDMONT AFTER 00Z...WITH THE BULK OF THE PRECIP AFTER
MIDNIGHT AS A 50KT LOW LEVEL JET SHIFTS ACROSS THE AREA.   PW VALUES
STAY BELOW 1.25"...BUT WITH ADDITIONAL SUPPORT FROM UPPER DIVERGENCE
IN THE LEFT EXIT REGION OF A SPEED MAX STRENGTHENING OVER THE DEEP
SOUTH...WOULD LEAN A LITTLE MORE TOWARD THE NAM/GFS QPF TOTALS WHICH
ARE HIGHER AND GIVE BETWEEN A QUARTER TO HALF INCH IN TOTAL.  WEAK
LAPSE RATES AND POOR DIURNAL TIMING WILL LIMIT INSTABILITY...THOUGH
THE GFS PRODUCES 200-300 J/KG MLCAPE AT KFAY AS IT STEEPENS MID-
LEVEL LAPSE RATES TO  AROUND 6 C/KM.  THIS SEEMS OVERDONE GIVEN
UPSTREAM SOUNDINGS...BUT IF THERE IS A CHANCE OF THUNDER IT SHOULD
BE IN THE SOUTHERN COASTAL PLAIN MONDAY MORNING.

STRONG 150+ METER HEIGHT FALLS AND A COLD FRONT WILL SWEEP ACROSS
THE AREA BY EARLY MONDAY AFTERNOON.  FORECAST SOUNDINGS SHOW 25-35KT
IN THE DEEPENING POST-FRONTAL MIXED LATER MONDAY AFTERNOON...BUT
MODELS CAN OFTEN OVERDO THESE GRADIENT WINDS.  WILL CAP WIND GUSTS
AT 30KT FOR NOW.

TEMPS MAY COOL INTO THE UPPER 40S ACROSS THE NORTH SUNDAY EVENING
BUT WILL LIKELY RISE BACK INTO THE 50S SUNDAY NIGHT AHEAD OF THE
FRONT.  GUIDANCE SUGGESTS THE COASTAL PLAIN MAY REACH THE 60S BY
EARLY MONDAY...BUT MOST AREAS WILL SEE TEMPS FALLING THROUGH THE DAY
ON MONDAY.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
AS OF 332 PM SATURDAY...

DEEPENING AREA OF LOW PRESSURE WILL CONTINUE MOVING NORTHEASTWARD
AWAY FROM THE MID ATLANTIC COAST... AND WINDS WILL DIMINISH
OVERNIGHT AS HIGH PRESSURE OVER THE OHIO VALLEY MOVES EASTWARD OVER
THE AREA ON MONDAY NIGHT INTO TUESDAY. THIS HIGH WILL MOVE OFF THE
COAST ON WEDNESDAY... PROVIDING COMPARATIVELY WARMER TEMPS IN
SOUTHWESTERLY FLOW. MEANWHILE... UPPER LEVEL LOW OVER THE SOUTHWEST
WILL GRADUALLY BEGIN TO OPEN INTO A WAVE AS IT MOVES EASTWARD TO THE
WESTERN GULF OF MEXICO... WHERE SURFACE LOW PRESSURE FORMS OVER THE
NORTHERN GULF. PROGRESSION OF THIS SYSTEM STILL REMAINS QUITE
UNCERTAIN... WITH CONSIDERABLE VARIATION AMONGST MODEL SOLUTIONS IN
HANDLING THE PRIMARY SOUTHERN STREAM ENERGY... AND THE TRAILING
NORTHERN STREAM WAVE. ECMWF REMAINS SUPPRESSED WITH THE SOUTHERN
STREAM UPPER LEVEL WAVE AND MUCH WEAKER WITH THE SECOND NORTHERN
STREAM ONE... AND PUSHES THE LOW EASTWARD OUT TO SEA WITH NO LOCAL
IMPACTS... WHILE THE GFS BRINGS THE LOW ALONG THE SOUTHEAST COAST AS
STRONGER NORTHERN STREAM ENERGY DIVES INTO THE AREA... RESULTING IN
WIDESPREAD RAIN THURSDAY. WITH NO STRONG CONSENSUS TO DRIVE A
DEVIATION FROM THE CURRENT FORECAST... WILL CONTINUE WITH SLIGHT TO
CHANCE POPS ON THURSDAY... WITH DRY CONDITIONS FRIDAY AND SATURDAY.
TEMPS WILL REMAIN BELOW NORMAL THURS THROUGH SAT.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
AS OF 945 PM SATURDAY...

24-HR TAF PERIOD: VFR CONDITIONS WILL RULE THROUGH THE MAJORITY OF
THE TAF PERIOD AS HIGH PRESSURE SHIFTS OFFSHORE THE CAROLINA
COAST...IN ADVANCE OF A POTENT UPPER LEVEL WAVE AND ATTENDANT SFC
LOW TRACKING EASTWARD FROM THE CENTRAL PLAINS INTO THE OH VALLEY.
CALM OR LIGHT/VARIABLE WINDS OVERNIGHT WILL BECOME S/SW AT 10-15 KT
BY 18Z SUN AFTERNOON. GUSTS UP TO 20-25 KT WILL BE POSSIBLE AT
EASTERN TERMINALS BETWEEN 18-21Z...ASSUMING INCREASING MID-LEVEL (10-
15 KFT) CEILINGS DO NOT SIGNIFICANTLY ALTER INSOLATION/MIXING. MVFR
CEILINGS (2000-3000 FT AGL) WILL BE POSSIBLE BY 21-00Z AT THE
INT/GSO TERMINALS AND ~00Z AT RDU/FAY/RWI TERMINALS AS LOW-LEVEL
MOISTURE INCREASES VIA SOUTHERLY FLOW IN ADVANCE OF AN APPROACHING
COLD FRONT. SHOWERS AND MVFR/IFR CEILINGS WILL BE POSSIBLE IN
ADVANCE OF THE FRONT BETWEEN 00-06Z MON AT THE INT/GSO TERMINALS.

LOOKING AHEAD: SHOWERS AND MVFR/IFR CEILINGS ARE EXPECTED AT ALL
TERMINALS BETWEEN 06-12Z MON...PERSISTING THROUGH 12-18Z MON AT
EASTERN TERMINALS. AN ABRUPT WIND SHIFT FROM SOUTHERLY TO WESTERLY
WILL OCCUR IN THE WAKE OF THE FRONT MONDAY AFTERNOON...WITH W/NW
WINDS BECOMING SUSTAINED AT 15-20 KT WITH GUSTS AS HIGH AS 30 KT MID
TO LATE MON AFTERNOON (~21Z). A NW BREEZE AT 10-15 KT WILL PERSIST
MON NIGHT AS HIGH PRESSURE BUILDS TOWARD THE REGION FROM THE WEST.
VFR CONDITIONS WILL RULE THROUGH MID-WEEK AS HIGH PRESSURE BUILDS
OVER THE CAROLINAS. -VINCENT
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...BLS
LONG TERM...SEC
AVIATION...VINCENT