501
FXUS62 KCAE 280542
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
142 AM EDT TUE JUL 28 2026
WHAT HAS CHANGED
AVIATION DISCUSSION UPDATED FOR 06Z TAF.
KEY MESSAGES
- 1. HOT/HUMID CONDITIONS TODAY WITH A HEAT ADVISORY IN EFFECT
FROM NOON TO 8PM ALONG AND SOUTH OF I-20 WITH HEAT INDICES UP
TO 108F POSSIBLE.
- 2. ISOLATED TO SCATTERED CHANCES TUESDAY EVENING. SEVERE
WEATHER IS POSSIBLE WITH THIS ACTIVITY. DRIER CONDITIONS THEN
MOVE IN FOR THE LATE WEEK.
DISCUSSION
- 1. HOT/HUMID CONDITIONS TODAY WITH A HEAT ADVISORY IN EFFECT
FROM NOON TO 8PM ALONG AND SOUTH OF I-20 WITH HEAT INDICES UP
TO 108F POSSIBLE.
OPPRESSIVE HEAT AND HUMIDITY ARE FORECAST TO DEVELOP AGAIN
ACROSS THE AREA TODAY, ESPECIALLY ACROSS THE COASTAL PLAIN. A
DEEPENING TROUGH ACROSS THE EASTERN CONUS WILL RESULT IN A BROAD
SURFACE LOW DEVELOPING, ALONG WITH A COLD FRONT RAPIDLY
APPROACHING THE AREA FROM THE NORTH. SOUTHWESTERLY WINDS ARE
FORECAST TO INCREASE TODAY, HELPING TO PUSH WARM AND MOISTURE
RICH AIR INTO THE REGION. WHILE DEWPOINTS ARE FORECAST TO REMAIN
IN THE 70S AND YIELD VERY HUMID CONDITIONS, THERE IS SOME
UNCERTAINTY IN JUST HOW HOT WE WILL GET TODAY. IT SEEMS LIKE
WE'LL BE ABLE TO GET INTO THE LOW-MID 90S BUT THE LATEST HI-RES
GUIDANCE SUGGESTS THAT A DECAYING MCS FROM THE OH VALLEY WILL BE
PUSHING TOWARDS THE REGION BY MIDDAY. THIS COULD THROW A MAJOR
WRENCH INTO THE TEMP FORECAST FOR TODAY. HOWEVER, EVEN STILL,
CONFIDENCE IS FAIRLY HIGH THAT AREAS ALONG AND SOUTH OF I20
SHOULD SEE MAX HEAT INDEX VALUES UP TO 108F.
- 2. ISOLATED TO SCATTERED CHANCES THIS AFTERNOON AND EVENING.
SEVERE WEATHER IS POSSIBLE WITH THIS ACTIVITY. DRIER
CONDITIONS THEN MOVE IN FOR THE LATE WEEK.
THERE IS CONSIDERABLE UNCERTAINTY REGARDING THE FORECAST FOR
TODAY IN MANY ASPECTS, BUT ESPECIALLY AS IT PERTAINS TO THE
FORECAST FOR STRONG TO SEVERE STORMS THIS AFTERNOON/EVENING. THE
SYNOPTIC PATTERN HAS NOT CHANGED TOO MUCH SINCE THIS TIME
YESTERDAY, THOUGH THE SPECIFICS OF THE ENVIRONMENT AHEAD OF THIS
SETUP HAVE CHANGED SLIGHTLY. A SHORTWAVE IN THE GREAT LAKES
IS STILL FORECAST TO DIVE INTO THE APPALACHIANS AND HELP
DEEPEN THE TROUGH THAT IS IN PLACE, BRINGING A COLD FRONT
THROUGH THE REGION BY WEDNESDAY AS WELL. HOWEVER, THERE IS
SUBSTANTIAL UNCERTAINTY AS TO WHAT THIS SHORTWAVE ACTUALLY DOES
AS IT MOVES SOUTHEASTWARD NEAR OUR AREA. THERE IS AN AREA OF
CONVECTION CURRENTLY ORGANIZING ACROSS MICHIGAN. 00Z CAMS -
ACROSS THE BOARD! - WERE IN LOVE WITH THIS CLUSTER OF CONVECTION
AND UNIVERSALLY FORECAST IT TO DIVE SOUTHWARD AND BE NEAR THE
AREA BY MIDDAY. IN THIS SCENARIO, THE WEAKENING CLUSTER OF
STORMS WOULD ALMOST CERTAINLY MAKE IT DIFFICULT FOR THE EASTERN
PORTIONS OF THE AREA TO SEE A TON OF DESTABILIZATION DURING THE
AFTERNOON HOURS. SOME OF THESE SOLUTIONS EVEN FAVOR SCATTERED
THUNDERSTORMS THEN DEVELOPING ACROSS THE WESTERN CAROLINAS AND
GEORGIA, A SCENARIO THAT SEEMED UNLIKELY AS RECENTLY AS
YESTERDAY.
HOWEVER, THERE IS SOME REASON TO BE SKEPTICAL OF THIS
IDEA. FOR STARTERS, THE CAMS WERE VARYING DEGREES OF HORRIBLE AT
ACTUALLY INITIALIZING CONVECTION EARLIER THIS EVENING AND NONE
OF THEM REALLY MANAGED THE EVOLUTION OF SAID CONVECTION WELL IN
THE FIRST 5ISH HOURS OF THE 00Z RUNS. THE HRRR HAS BEEN SLOWING
THE ARRIVAL TIME OF THIS CLUSTER (AND WEAKENING IT) OVER THE
LAST SEVERAL RUNS. CAM GUIDANCE HAS NOT DONE WELL WITH THIS
SYNOPTIC REGIME THIS WEEK, ROUTINELY STRUGGLING EVEN UPSTREAM IN
THE GREAT LAKES WHERE CONVECTION HAS BEEN WELL FORCED. IT DOES
SEEM REASONABLE TO EXPECT THAT THIS CONVECTION WILL EXIST IN
SOME FORM, LIKELY FORCED BY THE AFOREMENTIONED STRONG SHORTWAVE.
SO THIS LEAVES US WITH THE NEED TO ASSESS WHAT THE ENVIRONMENT
AWAITING THE FORCING WILL BE LIKE. THIS IS UNCERTAIN AS WELL, AS
THERE IS A GOOD BIT OF SPREAD AMONGST REFS/HREF MEMBERS OVER THE
DEGREE OF DESTABILIZATION AND MIXING THAT OCCURS THIS
AFTERNOON. LOOKING AT SATELLITE DERIVED PWS, IT DOES LOOK LIKE
THERE MAY BE SOME SLIGHTLY DRIER AIR PUSHING SOUTHEASTWARD
WITHIN THE OVERALL FLOW, WHICH MAY AID IN ALLOWING US TO MIX
SLIGHTLY MORE THAN WOULD BE EXPECTED IF IT WERE A BIT MORE MOIST
(THOUGH NOT MIXING AS MUCH AS THE HRRR SUGGESTS). BUT EVEN IF
DEWPOINTS BUMP DOWN INTO THE 68F-70F RANGE, SBCAPE SHOULD STILL
BE AROUND 2000+ J/KG, ESPECIALLY ACROSS THE NORTHERN MIDLANDS
NEAREST THE APPROACHING FRONT. WIND PROFILES ACTUALLY LOOK QUITE
ROBUST FOR JULY AS THE TROUGH SETTLES INTO PLACE, WITH 30-40
KNOTS OF EFFECTIVE SHEAR PER RAP AND REFS MEAN SOUNDINGS. THIS
THE COMBINATION OF FORCING, INSTABILITY, AND SHEAR (ESPECIALLY
IN THE NORTHERN HALF OF THE AREA) IS ENOUGH TO JUSTIFY THE
SLIGHT RISK FROM SPC THAT IS THERE. BUT THE EXACTS OF THIS
SETUP? WHO KNOWS. FORECASTER CONFIDENCE IS LOW IN THIS SETUP,
ESPECIALLY SINCE THE BACKGROUND SYNOPTIC ENVIRONMENT FAVORS
CONVECTION TO OUR NORTH AND NORTHEAST. BUT GIVEN WE HAVE ACTUAL
SHEAR OVERLAPPING WITH SUMMERTIME MOISTURE AND INSTABILITY,
DAMAGING WIND GUSTS WITH STRONG MULTI-CELL CLUSTERS IS THE MOST
LIKELY SEVERE HAZARD.
THE FRONT IS FORECAST TO SLIDE THROUGH THE AREA ON WEDNESDAY.
DRIER, ALBEIT NOT COOLER, AIR IS FORECAST TO ARRIVE BEHIND IT,
PROVIDING QUITE THE RELIEF FROM THE OPPRESSIVE HUMIDITY THAT WE
HAVE BEEN EXPERIENCING THE LAST SEVERAL WEEKS. PWS ARE FORECAST
TO FALL TO AROUND 1", WHICH SHOULD RESULT IN DEWPOINTS FALLING
INTO THE 60S ACROSS THE AREA. IT WON'T BE ANYTHING TOO CRAZY,
BUT IT WILL BE A NICE BREAK FROM OPPRESSIVE HUMIDITY. AS THE
WELL-ADVERTISED TROUGH CONTINUES TO RETROGRADE WESTWARD, AN
INCREASE IN MOISTURE IS EXPECTED OVER THE WEEKEND. STILL
EXPECTING RAIN CHANCES TO INCREASE SAT-MON AS A RESULT.
AVIATION /06Z TUESDAY THROUGH SATURDAY/
BRIEF MORNING FOG/STRATUS POSSIBLE.
LIGHT AND VARIABLE OR CALM WINDS OVERNIGHT MAY FAVOR MORNING
FOG/STRATUS. HOWEVER CONVECTIVE DEBRIS CLOUDINESS OVER THE AREA
WILL HINDER A WIDESPREAD FOG THREAT. GUIDANCE IS NOT AS
PESSIMISTIC AS YESTERDAY BUT CONTINUED TEMPO GROUPS FOR VSBY
RESTRICTIONS EARLY THIS MORNING. WINDS PICK UP FROM THE
SOUTHWEST BY 15Z TODAY AND INCREASE TO AROUND 10 KNOTS BY 19Z
WITH SOME GUSTS UP TO 20 KNOTS THROUGH THE AFTERNOON AHEAD OF AN
APPROACHING FRONT. CONVECTION IS EXPECTED TO DEVELOP ALONG THE
FRONT LATE TODAY BUT REMAIN TO OUR NORTH THROUGH 00Z. GUSTS
SHOULD SUBSIDE AFTER 00Z. AS CONVECTION CONTINUES SOUTH THROUGH
THE EVENING WE EXPECT STORMS TO DIMINISH BUT COULD STILL NEAR
CAE/CUB BETWEEN 00Z AND 06Z.
EXTENDED AVIATION OUTLOOK...RAIN CHANCES INCREASE MID-WEEK WITH
RESTRICTIONS POSSIBLE AS A FRONT PUSHES INTO THE SOUTHEAST.
DRIER AIR MOVES IN FOR THE SECOND HALF OF THE WEEK.
CAE WATCHES/WARNINGS/ADVISORIES
SC...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
SCZ016-022-027>031-035-037-038-041-135>137.
GA...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
GAZ063>065-077.
DISCUSSION...PL
AVIATION...CJR
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page