Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 290731
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
331 AM EDT MON SEP 29 2014

.SYNOPSIS...
MOISTURE WILL INCREASE ACROSS THE REGION TODAY AS LOW PRESSURE
DEVELOPS OFF CAROLINA COAST. DRY HIGH PRESSURE WILL THEN BUILD IN ON
TUESDAY AND LINGER THROUGH THURSDAY. A COLD FRONT WILL ARRIVE FROM
THE NORTHWEST ON FRIDAY. A DRY AND COOL AIR MASS IS EXPECTED TO
ARRIVE ACROSS THE REGION NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 AM...THE KGSP RADAR SHOWS BANDS AND PATCHES OF LIGHT RAIN
MOVING NE ACROSS THE REGION...AND THIS TREND SHOULD CONTINUE WITH
COVERAGE INCREASING THROUGH DAYBREAK. SOME ADJUSTMENT WAS MADE TO
LOWER PRECIP CHANCES EARLY ON ACROSS THE NC PIEDMONT...BUT THAT AREA
SHOULD EVENTUALLY FILL IN A BIT AROUND DAYBREAK AS WELL. TEMPS WILL
REMAIN NEARLY STEADY.

AS FOR TODAY...AS WAS SUSPECTED ALL ALONG...IT LOOKS AS IF
SIGNIFICANT PRECIP WILL BYPASS THE WESTERN CAROLINAS AND NE GEORGIA
TO THE SOUTH. THAT BEING SAID...WILL CONTINUE TO FCST A RELATIVELY
HIGH PRECIP PROBABILITY BECAUSE OF THE DEGREE OF MID LEVEL FORCING
EXPECTED TO MOVE OVERHEAD AS THE SHORT WAVE DROPS DOWN INTO THE
REGION AND THE UPPER JET STREAK LIFTS NE. READERS ARE REMINDED THAT
THE PRECIP PROBABILITY IN THE FCST IS THE PROBABILITY OF GETTING AT
LEAST 0.01 INCH OF RAIN...AND THAT A VERY HIGH POP DOES NOT
NECESSARILY CORRELATE TO A HIGH AMOUNT OF PRECIPITATION. SO...WE ARE
LEFT WITH A HIGH PROBABILITY OF RECEIVING A VERY LITTLE BIT OF RAIN.
WHAT RAIN FALLS SHOULD GET PUSHED OFF TO THE EAST BY LATE AFTERNOON
AND EARLY EVENING BY THE PASSAGE OF THE SHORT WAVE. WILL END PRECIP
CHANCES STEADILY FROM THE WEST THROUGH THE EVENING HOURS. THE
REMAINING CONCERN WILL BE FOG IN THE PRE-DAWN HOURS ON TUESDAY. WIND
SHOULD BE FAIRLY LIGHT AND MID/UPPER LEVELS SHOULD DRY OUT
DRAMATICALLY. ASSUMING SOME LIGHT PRECIP FALLS TODAY...THAT COULD
PROVIDE FOR ENOUGH LOW LEVEL MOISTURE TO HELP WIDESPREAD FOG TO
DEVELOP BEFORE DAYBREAK TUESDAY...SO IT WILL BE INCLUDED.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 245 AM MONDAY...FAIR WEATHER EXPECTED TUESDAY THROUGH
WEDNESDAY. SHORT RANGE MODELS INDICATE THAT SHALLOW MID LEVEL
RIDGING WILL RIPPLE ACROSS THE REGION THROUGH THE PERIOD. AT THE
SFC...A WEAK LEE TROF WILL LIKELY DEVELOP DURING THE DAYLIGHT HOURS
EACH DAY. HIGH TEMPERATURES ON TUESDAY ARE FORECAST TO RANGE FROM
UPPER 70S WITHIN THE MTN VALLEYS AND FOOTHILLS WITH VALUES NEAR 80
ACROSS THE PIEDMONT. ON THURSDAY...INCREASING LLVL THICKNESSES AND
PLENTIFUL INSOLATION SHOULD RESULT IN HIGH TEMPERATURES 2 TO 3
DEGREES ABOVE TUESDAY/S VALUES. OTHERWISE...CONDITIONS WILL REMAIN
DRY WITH LIGHT WINDS.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 315 AM MONDAY...THURSDAY...MOISTURE WILL BEGIN TO INCREASE
ACROSS THE SOUTHERN APPALACHIAN REGION AHEAD OF AN APPROACHING L/W
TROUGH. THE AXIS OF THE MID LEVEL RIDGE WILL SLIDE OVER THE ATLANTIC
COAST...WITH H85 TEMPS ACROSS CWA UNCHANGED FROM TUESDAY. HIGH
TEMPERATURES ARE FORECAST TO RANGE FROM THE U70S WITHIN THE MTN
VALLEYS TO NEAR 80 EAST OF I-85.

ON FRIDAY INTO FRIDAY NIGHT...THE AXIS OF THE L/W TROUGH AND SFC
COLD FRONT WILL SWEEP QUICKLY ACROSS THE REGION. FORECAST SOUNDINGS
INDICATE THE SFC CAPE WILL REMAIN BETWEEN 100-300 J/KG AHEAD OF THE
FRONT. HOWEVER...PW VALUES WILL LIKELY SURGE TO 1.7 INCHES BY FRIDAY
AFTERNOON. THE COMBINATION OF THE PASSING FRONT AND TROUGH...WEAK
INSTABILITY...AND DEEP MOISTURE SHOULD SUPPORT A BAND OF LIGHT TO
MODERATE RAIN AND A FEW TSRA ON FRIDAY. PEAK COVERAGE IS EXPECTED
AROUND MID DAY FRIDAY...HIGHLIGHTED WITH LIKELY POPS ACROSS THE MTNS
AND CHC POPS EAST. HIGH TEMPERATURES SHOULD RANGE A FEW DEGREES
BELOW NORMAL,

NEXT WEEKEND...IN THE WAKE OF THE COLD FRONT...SFC HIGH PRESSURE IS
EXPECTED TO PUSH ACROSS THE SOUTHERN MISSISSIPPI RIVER ON
SATURDAY...REACHING THE SOUTHEAST U.S. ON SUNDAY. CONDITIONS SHOULD
REMAIN CLEAR AND DRY. TEMPERATURES WILL LIKELY RANGE SEVERAL DEGREES
BELOW NORMAL.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
AT KCLT...VFR CONDITIONS MOST LIKELY THROUGH THE PERIOD. A HIGH
BASED STRATOCU AND ALTOCU CEILING WILL PREVAIL THROUGH LATE
AFTERNOON. LATEST GUIDANCE SUGGEST THAT LIGHT RAIN WILL FALL OUT OF
THIS CLOUD DECK BUT NOT AT A GREAT ENOUGH RATE TO BRING THE CEILING
DOWN OR LOWER VSBY ENOUGH FOR MVFR. HAVE INCLUDED A TEMPORARY CLOUD
DECK BLO 050 IN THE EVENT THAT SOME LOWER CLOUDS SEEN ON SFC OBS
OVER CENTRAL/ERN GA MAKE IT THIS FAR N. WILL FURTHER EVALUATE THIS
IN LATER ISSUANCES. THE LIGHT RAIN SHOULD MOVE AWAY AROUND 23Z TO
01Z AS THE BETTER UPPER FORCING SHIFTS EWD. WIND SHOULD BE LIGHT N
TO NE THROUGH THE PERIOD.

ELSEWHERE...SIMILAR TO KCLT WITH CONDITIONS MAINLY VFR THROUGH THE
PERIOD. HOWEVER...SOME LOWER CLOUDS ARE NOTED OVER CENTRAL GA MAKING
INROADS TOWARD THE SRN PART OF THE FCST AREA. WILL START WITH A
TEMPO FOR MVFR CEILING AT KAND AND SEE HOW THIS EVOLVES. THINK THE
LAMP GUIDANCE IS OVERDONE WITH FOG ACROSS THE MTNS ONCE AGAIN...BUT
FEW LOW STRATOCU AT KAVL SUGGESTS THAT A TEMPO FOR MVFR IS WARRANTED
THROUGH THE EARLY MORNING HOURS. WILL MONITOR OBS AT K1A5 AND AMEND
ACCORDINGLY. OTHERWISE...RAIN NOT EXPECTED TO COME DOWN AT A RATE
GREAT ENUF TO REDUCE VSBY.

OUTLOOK...COULD BE SOME DENSE FOG ACROSS THE REGION EARLY TUESDAY
MORNING AS DRY AIR MOVES IN ALOFT BEHIND A DEPARTING SFC LOW...
PROVIDED WE SEE SOME LIGHT RAIN TODAY. VFR CONDITIONS WILL PREVAIL
TUESDAY THROUGH FRIDAY MORNING...WITH FOG/VSBY CONCERNS REMAINING
ACROSS THE MTNS AND FOOTHILLS EARLY EACH MORNING. A FRONT WILL
APPROACH ON FRIDAY WHICH COULD TRIGGER SOME SHOWERS AND
THUNDERSTORMS.

CONFIDENCE TABLE...

            07-13Z        13-19Z        19-01Z        01-07Z
KCLT       HIGH 100%     HIGH  93%     HIGH  92%     HIGH  86%
KGSP       HIGH 100%     HIGH  91%     HIGH  91%     HIGH  82%
KAVL       MED   68%     HIGH  88%     HIGH  92%     HIGH  85%
KHKY       HIGH  93%     HIGH  93%     HIGH  92%     HIGH  98%
KGMU       HIGH 100%     HIGH  91%     HIGH  86%     MED   79%
KAND       HIGH  94%     HIGH  93%     HIGH  90%     HIGH  82%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...NED
NEAR TERM...PM
SHORT TERM...NED
LONG TERM...NED
AVIATION...PM





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