808
FXUS62 KRAH 180128
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
930 PM EDT WED AUG 17 2022
SYNOPSIS
HIGH PRESSURE WILL EXTEND INTO THE AREA FROM THE NORTH THROUGH
TONIGHT, THEN DRIFT OFFSHORE ON THURSDAY. A STALLED FRONT OVER THE
SOUTHEAST STATES WILL MOVE NORTH AS A WARM FRONT FRIDAY INTO
SATURDAY.
NEAR TERM /THROUGH TONIGHT/
AS OF 930 PM WEDNESDAY...
THERE WERE A COUPLE OF WEAK MID-LEVEL WAVES CROSSING SOUTHERN NC
THIS EVENING. VERY DRY AIR CONTINUED TO BE LOCATED IN THE MID AND
UPPER LEVELS WITH ESSENTIALLY VERY LITTLE MOISTURE TO WORK WITH.
THERE WERE A FEW CIRRUS/CIRROSTRATUS ALONG THE SOUTHERN TIER OF
COUNTIES, WITH SOME STRATOCUMULUS OVER THE FAR WEST ASSOCIATED WITH
THE LIGHT UPSLOPE FLOW THERE. SKIES ON AVERAGE WERE PARTLY CLOUDY
EXCEPT MOSTLY CLEAR ACROSS THE NORTH. THE TEMPERATURES WERE RUNNING
JUST ABOUT ON TARGET FOR LOWS IN THE UPPER 50S TO MID 60S.
PREVIOUS DISCUSSION AS OF 240 PM WEDNESDAY...
SCATTERED TO BROKEN MULTI-LAYER CLOUDS PERSIST, MOSTLY IN THE 4K-10K
FT RANGE, WITH THICKER MOSTLY MID-HIGH LEVEL CLOUDS POISED TO STREAM
ACROSS S AND W SECTIONS OVER THE NEXT SEVERAL HOURS. BUT GOES LAYER
WV IMAGERY SHOWS THAT, APART FROM THE AFOREMENTIONED SHOT OF CLOUDS,
THE COLUMN IS RATHER DRY IN THE UPPER LEVELS, ESP OVER OUR N AND NE
SECTIONS. THE LARGE UPPER LOW NOW SPINNING JUST OFF THE S MAINE
COAST WILL CONTINUE TO WOBBLE SLOWLY NORTHWESTWARD THROUGH TONIGHT,
KEEPING A BROAD CYCLONIC FLOW ACROSS NC, ALTHOUGH ANY FORCING FOR
ASCENT WITHIN THIS FLOW WILL BE MINOR TO ABSENT. ONE SMALL WAVE
EMBEDDED IN THIS FLOW, ASSOCIATED WITH THE INCOMING BATCH OF CLOUDS,
WILL LARGELY PASS TO OUR S THIS EVENING INTO THE OVERNIGHT HOURS,
WHILE A SECOND WAVE WILL SHEAR OUT AS IT APPROACHES THE NC MOUNTAINS
LATE TONIGHT. THE LOWER-TROPOSPHERIC MOISTURE WILL BE A PATCHWORK,
AND WITH MINIMAL HIGHER LEVEL MOISTURE AND NO TRIGGER TO PROMPT LIFT
(INCLUDING CURRENT SUB-200 J/KG CAPE), EXPECT LARGELY DRY WEATHER
TONIGHT, ALTHOUGH A QUICK SPOTTY SHOWER CAN'T BE RULED OUT ACROSS
THE FAR W AND FAR S THROUGH EARLY EVENING. NE WINDS WILL STAY MOSTLY
UNDER 12 MPH THROUGH THE REST OF THE AFTERNOON BEFORE BECOMING
LIGHT/VARIABLE TOWARD SUNSET. EXPECT HIGHS MOSTLY IN THE 60S, WITH
SOME UPPER 50S IN LOW AND RURAL AREAS. -GIH
SHORT TERM /THURSDAY AND THURSDAY NIGHT/
AS OF 300 PM WEDNESDAY...
THE UPPER-LOW ACROSS NEW ENGLAND WILL EJECT NORTHEAST DURING THE DAY
ON THURSDAY AS A SHORTWAVE DIGS SE FROM THE CENTRAL PLAINS TO THE OH
VALLEY. THIS WILL SWITCH FLOW ALOFT ACROSS CENTRAL NC FROM ZONAL
DURING THE DAY, TO SOUTHWESTERLY BY THURSDAY NIGHT. AT THE SURFACE,
HIGH PRESSURE WILL REMAIN ACROSS THE MID-ATLANTIC, WITH THE STALLED
FRONT STRETCHING FROM WEST TO EAST ACROSS AL/MS/GA. THE HIGH WILL
PUSH EAST OFF THE COAST THROUGHOUT THE DAY, AND SHIFT SURFACE FLOW
TO MORE E/SE BY THURSDAY NIGHT. CONDITIONS WILL BE DRY TO START THE
DAY, THEN ISOLATED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ACROSS THE
S AND NW PIEDMONT AS A SURGE OF LOWER-LEVEL MOISTURE MOVES INTO THE
REGION AND CONVECTION DEVELOPS ACROSS THE FOOTHILLS. PRECIP CHANCES
INCREASE ACROSS THE SOUTHWESTERN HALF OF THE REGION THURSDAY NIGHT
AS AN UPPER-WAVE APPROACHES THE REGION AND THE RIGHT ENTRANCE REGION
OF A WEAK UPPER JET MOVES IN ALOFT. SEVERE WEATHER IS NOT EXPECTED
AT THIS TIME. HIGHS WILL REMAIN BELOW NORMAL, RANGING FROM THE LOW
80S NW TO MID 80S E. LOWS WILL BE MORE MILD WITH INCREASING CLOUD
COVER, RANGING FROM THE MID TO UPPER 60S.
.LONG TERM /FRIDAY THROUGH WEDNESDAY/
AS OF 330 PM WEDNESDAY...
WET WEATHER AND HIGHER HEAT INDEX VALUES WILL RETURN LATE THIS WEEK
INTO MID-NEXT WEEK...
AN UPPER-LEVEL LOW WILL DIG FROM THE NORTHERN PLAINS ON THURSDAY
INTO THE OH VALLEY/GREAT LAKES REGION BY SUNDAY. THE LOW WILL THEN
WEAKEN AND LIFT NORTHEAST BY THE MIDDLE OF NEXT WEEK, WITH OVERALL
TROUGHING REMAINING ACROSS THE APPALACHIANS. THE SURFACE FRONT
STALLED TO OUR SOUTH THIS WEEK WILL LIFT NORTH ACROSS THE CAROLINAS
BY THIS WEEKEND, AND STALL AGAIN ACROSS OUR AREA THROUGH EARLY/MID-
NEXT WEEK.
FLOW SHIFTING SOUTHWESTERLY ALOFT WILL OPEN THE DOOR TO ENHANCED
MOISTURE ACROSS THE REGION, AND MULTIPLE EMBEDDED WAVES MOVING
ACROSS CENTRAL NC THROUGH THE LONG TERM. ADDITIONALLY, THE STALLED
SURFACE FRONT WILL HELP MAINTAIN HIGHER PRECIPITATION CHANCES ACROSS
THE REGION, OUTSIDE OF DIURNAL CONVECTION AND THE EMBEDDED WAVES
ALOFT. PRECIPITATION COULD BE HEAVY AT TIMES, ESPECIALLY ON FRIDAY
AND AGAIN NEXT MONDAY AS PRECIPITABLE WATER VALUES INCREASE TO NEAR
2 INCHES BOTH DAYS. AS OF NOW, WPC HAS THE SOUTHERN HALF OF CENTRAL
NC IN A MARGINAL RISK OF EXCESSIVE RAINFALL ON FRIDAY, BUT GIVEN THE
ENVIRONMENT, THIS MAY EXPAND TO ALL AREAS OF CENTRAL NC WITH FURTHER
UPDATES.
ALTHOUGH HIGHS WILL REMAIN IN THE 80S THROUGH THE EXTENDED FORECAST,
DEWPOINT TEMPERATURES WILL INCREASE INTO THE LOW TO MID 70S AS
SOUTHERLY FLOW INCREASES MOISTURE ACROSS THE REGION. THIS WILL MAKE
IT FEEL MORE LIKE THE LOW TO MID 90S FOR THE SOUTHERN HALF OF
CENTRAL NC ON SUNDAY, WITH LOWER HEAT INDEX VALUES ON REMAINING
DAYS. LOWS WILL REMAIN MORE MILD, RANGING FROM THE UPPER 60S TO LOW
70S.
AVIATION /00Z THURSDAY THROUGH MONDAY/
AS OF 735 PM WEDNESDAY...
GENERALLY VFR CONDITIONS WITH HIGH PRESSURE WILL CONTINUE TONIGHT
INTO THURSDAY. SCATTERED TO OCCASIONALLY MULTI-LAYERED VFR
CLOUDINESS CAN EXPECTED.
LOOKING BEYOND 18Z THU, VFR CONDITIONS SHOULD HOLD THROUGH FRI
MORNING AS HIGH PRESSURE EXTENDING INTO THE REGION SHIFTS OFFSHORE.
THIS WILL ALLOW THE FRONT TO OUR SOUTH TO SHIFT NORTHWARD THROUGH NC
FROM FRI THROUGH SAT, IN TANDEM WITH PASSAGE OF AN UPPER LEVEL
DISTURBANCE THROUGH THE AREA. CLOUD BASES WILL THICKEN AND LOWER
STARTING MIDDAY FRI. SEVERAL HOURS OF HIGH RAIN/STORM CHANCES AND
SUB-VFR CONDITIONS ARE THEN EXPECTED, WITH THE GREATEST CHANCES FROM
LATE FRI AFTERNOON THROUGH SAT MORNING. VFR CONDITIONS WILL DOMINATE
LATE SAT THROUGH MON, ALTHOUGH THERE WILL BE A GOOD CHANCE FOR
AFTERNOON AND EVENING SHOWERS AND STORMS SUN/MON. -GIH
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...KREN
NEAR TERM...PWB/HARTFIELD
SHORT TERM...JJT
LONG TERM...JJT
AVIATION...PWB/HARTFIELD
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