Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 291350
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
950 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/...
AT 1000 AM EDT...AN UPPER TROUGH EXTENDED FROM THE GREAT LAKES TO
THE NE GULF OF MEXICO THIS MORNING...WITH SHORTWAVE MOVING THROUGH
IT OVER THE SOUTHERN APPALACHIANS AND THE MID MS RIVER VALLEY. A
SURFACE STATIONARY FRONT WAS LOCATED FROM THE CAROLINA AND GA
COASTS TO THE GULF COAST.

ALTHOUGH MODEL DATA SHOWS LITTLE TO NO ISENTROPIC UPGLIDE OVER THE
COASTAL FRONT...AS LEAST OVER OUR AREA... PRECIPIATION ASSOCIATED
WITH THE FIRST SHORTWAVE WAS NOTED CROSSING THE PIEDMONT...AND
ADDITIONAL ACTIVITY CAN BE EXPECTED AS THE SECOND SHORTWAVE ADVANCES
LATER TODAY. THE MODELS CONTINUE TO SHOW ENOUGH INSTABILITY OVER
THE NC MOUNTAINS FOR THUNDERSTORMS THIS AFTERNOON...BUT NOT ENOUGH
TO SUPPORT STRONG UPDRAFTS OR SEVERE WEATHER. PRECIPITATION AMOUNTS
ARE EXPECTED TO BE RATHER LIGHT.

PREVIOUS DISCUSSION...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 /14Z MONDAY THROUGH FRIDAY/...
AT KCLT...VFR CONDITIONS MOST LIKELY THROUGH THE EVENING. 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. OBS AND RADAR TRENDS BEAR THIS
OUT AS OF 11Z. 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. CLEARING SKY AND DRY AIR MOVING IN AT MID/UPPER LEVELS WILL
SET UP A DECENT POTENTIAL FOR WIDESPREAD FOG EARLY TUESDAY MORNING.
WILL LIMIT VISIBILITY TO MVFR RANGE AFTER 10Z AND EVALUATE FURTHER
WITH LATER ISSUANCES.

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.
OTHERWISE...RAIN NOT EXPECTED TO COME DOWN AT A RATE GREAT ENUF TO
REDUCE VSBY. CLOUDS WILL MOVE OUT A SOONER THAN KCLT LATER THIS
EVENING WHICH WILL PROVIDE MORE OPPORTUNITY FOR FOG FORMATION...
ESPECIALLY OVER THE NC MTNS. THINK THE GUIDANCE MIGHT ACTUALLY BE ON
TO SOMETHING THIS TIME WITH VLIFR IN THE MTN VALLEYS. WILL LIMIT
KAVL TO IFR FOR THE TIME BEING...BUT OTHER LOCATIONS COULD ALSO MAKE
TO IFR IF FOG BECOMES WIDESPREAD.

OUTLOOK...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...

            14-20Z        20-02Z        02-08Z        08-14Z
KCLT       HIGH 100%     HIGH  98%     HIGH  88%     HIGH  94%
KGSP       HIGH  89%     HIGH  89%     HIGH  89%     HIGH  90%
KAVL       HIGH  91%     HIGH  94%     HIGH  85%     HIGH  82%
KHKY       HIGH  89%     HIGH 100%     HIGH  91%     HIGH  98%
KGMU       HIGH  90%     HIGH  89%     HIGH  89%     HIGH  94%
KAND       HIGH  93%     HIGH  91%     HIGH  89%     HIGH  90%

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

&&

.FIRE WEATHER...
THE PLANNING FORECAST HAS BEEN UPDATED TO LOWER MIXING HEIGHTS
AROUND 1000 FEET TODAY BASED ON THE LATEST MODEL SOUNDINGS AND
PRECIPITATION. TRANSPORT WINDS WERE LOWERED TONIGHT. SMOKE
MANAGEMENT PARAMETERS HAVE BEEN ADJUSTED ACCORDINGLY.

&&

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

&&

$$
SYNOPSIS...NED
NEAR TERM...JAT/PM
SHORT TERM...NED
LONG TERM...NED
AVIATION...PM
FIRE WEATHER...JAT





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