057
FXUS62 KCAE 200617
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
217 AM EDT MON JUL 20 2026
WHAT HAS CHANGED
CONFIDENCE IN A FAIRLY ACTIVE PATTERN DURING THE MID TO LATE
WEEK CONTINUES TO INCREASE. AVIATION DISCUSSION UPDATED FOR 06Z
TAFS.
KEY MESSAGES
- 1. ISOLATED TO WIDELY SCATTERED CONVECTION POSSIBLE TODAY AND
TUESDAY WITH HOT/HUMID CONDITIONS CONTINUING.
- 2. A MORE ACTIVE PATTERN IS EXPECTED DURING THE MID TO LATE
WEEK WITH SLIGHTLY COOLER TEMPERATURES AND CHANCES FOR
STRONGER THUNDERSTORMS WEDNESDAY.
DISCUSSION
KEY MESSAGE 1: ISOLATED TO WIDELY SCATTERED CONVECTION POSSIBLE
TODAY AND TUESDAY WITH HOT/HUMID CONDITIONS CONTINUING.
TD TWO IS EXPECTED TO BEGIN SLOWLY DRIFTING NNW ACROSS THE GULF
THROUGH THE DAY TODAY AS LOW LEVEL FLOW OVER THE FA BECOMES
INCREASINGLY SOUTHERLY. THE PLUME OF DEEPEST MOISTURE ASSOCIATED
WITH THIS SYSTEM IS EXPECTED TO REMAIN CONFINED TOWARD THE GULF
COAST, BUT PWAT'S BETWEEN 1.85-2" ARE EXPECTED TO REMAIN OVER
THE REGION. SURFACE TROUGHING IS EXPECTED TO GRADUALLY WEAKEN
THROUGH THE DAY, BUT PIECES OF SHORTWAVE ENERGY FROM THE
TROUGHING PATTERN OVER THE EASTERN CONUS ARE EXPECTED TO PASS
NEAR THE PEE DEE THIS AFTERNOON/EVENING. SURFACE DEWPOINTS ARE
EXPECTED TO REMAIN IN THE UPPER 60S TO LOW 70S WITH MEAN HREF
MUCAPE VALUES NEARING 2000 J/KG THROUGH THE DAY WITH LINGERING
CLOUD LAYER SHEAR VALUES NEAR 20-30 KTS. WITH THE SUBTLE NATURE
OF FORCING, EXPECT CONVECTIVE COVERAGE THIS AFTERNOON/EVENING TO
BE FAIRLY ISOLATED WITH THE BEST CHANCES ALONG AND EAST OF THE
I-26 CORRIDOR. GENEROUS MIXING SHOULD ONCE AGAIN YIELD DCAPE
VALUES THAT COULD CLOSE IN ON 1000 J/KG SO A STRONGER STORM
CANNOT BE RULED OUT WITH THIS ACTIVITY. TUESDAY LIKELY ACTS AS A
TRANSITION DAY WHERE SURFACE TROUGHING AND ANY UPPER SUPPORT
EXIT THE CWA, BUT HOT/HUMID CONDITIONS SHOULD STILL YIELD
SEASONABLE INSTABILITY AND ISOLATED DIURNAL SHOWER/STORM
CHANCES. TEMPERATURES TODAY AND TUESDAY ARE EXPECTED TO ONCE
AGAIN PUSH THE MID TO UPPER 90S WITH HEAT INDICES UP TO 100-106F
EXPECTED, REMAINING JUST UNDER HEAT ADVISORY CRITERIA.
KEY MESSAGE 2: A MORE ACTIVE PATTERN IS EXPECTED DURING THE MID
TO LATE WEEK WITH SLIGHTLY COOLER TEMPERATURES AND CHANCES FOR
STRONGER THUNDERSTORMS WEDNESDAY.
THE UPPER PATTERN IS EXPECTED TO AMPLIFY A BIT THROUGH THE DAY
WEDNESDAY AND INTO THE LATE WEEK AS BOTH THE EC ENSEMBLE AND
GEFS MEAN SOLUTIONS SHOW A STRONG TROUGH (500MB HEIGHTS 2-2.5
STANDARD DEVIATIONS BELOW NORMAL) EXTENDING FROM THE EASTERN
GREAT LAKES DOWN INTO THE MID-ATLANTIC. THIS TROUGH IS EXPECTED
TO PUSH A COLD FRONT DOWN INTO THE REGION WHICH COULD NEAR THE
FA BY LATE WEDNESDAY WHERE IVT AHEAD OF THE FRONT COULD REACH
THE NAEFS 90TH TO 99TH PERCENTILE AND PWAT'S EXCEED 2". LREF
CLUSTER ANALYSIS SHOWS UNCERTAINTY IN THE DEPTH OF THE UPPER
TROUGH EXISTS, BUT EVEN WEAKER SOLUTIONS SHOW DECENT PVA AND
KINEMATICS REACHING THE FA WITH DEEP LAYER SHEAR NEARING 20-30
KTS AND A 20-25 KT LLJ IN PLACE. WITH SEASONABLE TO MODERATE
INSTABILITY LIKELY IN PLACE, THIS TROUGH AND FRONT COULD BRING A
CHANCE FOR MORE WIDESPREAD SHOWER/STORM CHANCES BY THE EVENING
WHERE STRONG TO SEVERE STORMS COULD BE POSSIBLE. GLOBAL MODELS
DEPICT THE FRONTAL BOUNDARY STALLING NEAR/WITHIN THE FA ON
THURSDAY AS ANOTHER SHORTWAVE LIKELY MOVES IN. WITH ANOMALOUS
IVT CONTINUING, SCATTERED TO WIDESPREAD RAIN CHANCES COULD
CONTINUE WHERE HEAVY RAINFALL WILL BE POSSIBLE AS EC ENSEMBLE
AND NBM PROBABILITIES FOR GREATER THAN 1" OF QPF NEAR 50-60%.
WITH THE REGION REMAINING IN NORTHWEST FLOW INTO THE WEEKEND, A
SERIES OF SHORTWAVES ARE EXPECTED TO CONTINUE PUSHING THROUGH,
BRINGING MORE RAIN CHANCES.
DUE TO UPPER TROUGHING AND INCREASED RAIN CHANCES, TEMPERATURES
THAT START NEAR NORMAL WEDNESDAY ARE EXPECTED TO COOL TO
SLIGHTLY BELOW NORMAL DURING THE LATE WEEK. FAIRLY LARGE 6-8
DEGREE IQR RANGES REMAIN DURING THIS TIME PERIOD, BUT EVEN THE
BLENDS 75TH PERCENTILE BRINGS TEMPERATURES RIGHT AROUND NORMAL.
AVIATION /06Z MONDAY THROUGH FRIDAY/
VFR CONDITIONS EXPECTED TO CONTINUE.
VFR CONDITIONS OVER THE AREA WITH FEW TO SCATTERED CLOUDS
AROUND 5KFT BUT RELATIVELY HIGH CONFIDENCE IN VFR CONDITIONS
CONTINUING THROUGH THE TAF PERIOD. WINDS WILL GENERALLY BE OUT
OF THE SSW, INCREASING DURING THE AFTERNOON WITH GUSTS GENERALLY
IN THE MID TO UPPER TEENS. WHILE GUIDANCE GENERALLY INDICATES A
BIT OF A DEEP LAYER MOISTURE INCREASE ASSOCIATED WITH A TROPICAL
DEPRESSION ALONG THE GULF COAST, CONVECTION COVERAGE WILL LIKELY
BE SOMEWHAT LIMITED AGAIN TODAY. CONFIDENCE REMAINS LOW IN
THUNDERSTORMS IMPACTING THE TERMINALS SO HAVE LEFT OUT THE
MENTION OF TSRA BUT WILL NEED TO MONITOR TRENDS IN HIGH
RESOLUTION GUIDANCE WITH SUBSEQUENT UPDATES.
EXTENDED AVIATION OUTLOOK...POTENTIAL FOR RESTRICTIONS FROM
SHOWERS AND THUNDERSTORMS CONTINUES WITH THE THREAT INCREASING
LATER IN THE WEEK.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...DH
AVIATION...96
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