787
FXUS63 KLSX 021131
AFDLSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NATIONAL WEATHER SERVICE SAINT LOUIS MO
631 AM CDT FRI JUN 2 2023
SHORT TERM
(THROUGH LATE SATURDAY AFTERNOON)
ISSUED AT 427 AM CDT FRI JUN 2 2023
THE PRIMARY FOCUS THROUGH SATURDAY WILL THE CHANCES FOR
DAY TIME SHOWERS AND THUNDERSTORMS AND ABOVE NORMAL TEMPERATURES.
HIGH PRESSURE TO THE NORTHEAST CONTINUES TO PROMOTE LOW LEVEL
EASTERLY FLOW THROUGH THE SHORT TERM. THIS EASTERLY FLOW WILL
CONTINUE TO PUSH DRIER AIR THAT AS OF 09Z IS OVER THE OHIO RIVER
VALLEY INTO THE REGION THROUGHOUT THE DAY TODAY WITH THE HIGHEST
MOISTURE CONTENT BEING OVER CENTRAL MO. TODAY, AREAS EAST OF THE
MISSISSIPPI RIVER CAN EXPECT LARGELY CLEAR SKIES WHILE AREAS WEST OF
THE RIVER CAN EXPECT DIURNAL CU DURING THE DAY. BY SATURDAY, THIS
DRY AIR WILL ENCOMPASS THE WHOLE AREA LEAVING SKIES MOSTLY CLEAR
WITH ISOLATED DIURNAL CU.
THE GREATEST CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BE TODAY
OVER CENTRAL MO WHERE THE MOISTURE CONTENT AND SURFACE INSTABILITY
IS THE HIGHEST. OVER 50% OF ENSEMBLE MEMBERS SUGGEST SURFACE BASED
CAPE VALUES IN EXCESS OF 1200 J/KG OVER CENTRAL MO, SUFFICIENT
ENOUGH TO PROMOTE ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS.
GIVEN THE WEAK SHEAR ENVIRONMENT, PULSE SHOWERS AND THUNDERSTORMS
ARE EXPECTED. SHOWERS AND THUNDERSTORMS ARE NOT EXPECTED ON
SATURDAY AS DRY AIR TAKES OVER.
HIGH TEMPERATURES TODAY ARE FORECAST TO BE IN THE UPPER 80S TO LOW
90S ACROSS THE AREA. THE HIGHEST TEMPERATURES ARE EXPECTED TO BE BE
IN THE ST. LOUIS METRO AREA AND THE MISSISSIPPI RIVER EASTWARD WHERE
CLOUD COVER WILL BE THE MOST LIMITED. TEMPERATURES ON SATURDAY WILL
BE THE WARMEST WITH HIGHS FORECASTED IN THE LOW TO MID 90S. RECORD
HIGH TEMPERATURES FOR ST. LOUIS ARE LIKELY TO BE CHALLENGED WITH
TEMPERATURES IN THE MID-90S. THE PREVIOUS RECORD HIGH WAS SET IN
2011 AT 96 DEGREES.
MMG/GLASS
LONG TERM
(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 427 AM CDT FRI JUN 2 2023
A HIGHER LATITUDE OMEGA BLOCK WILL BE IN PLACE AT THE START OF THE
PERIOD FEATURING AN ANOMALOUSLY STRONG UPPER HIGH CENTERED NEAR
LAKE WINNIPEG. RATHER DEEP BUT WEAK LOW-MID LEVEL EASTERLY FLOW
WILL PERSIST ACROSS THE REGION. WITHIN THIS FLOW REGIME, A VORT
MAX WILL MIGRATE EASTWARD FROM THE OHIO VALLEY ACCOMPANIED BY A
SLUG OF "BETTER" MOISTURE AND TRAVERSE THE REGION ON SUNDAY. OTHER
THAN THE VORT MAX THERE IS A LACK OF FORCING. CUMULATIVELY THE
VORT MAX/MOISTURE ALONG WITH VERY WEAK DEEP LAYER SHEAR, WOULD
SUGGEST POTENTIAL FOR ISOLATED-WIDELY SCATTERED DIURNAL PULSE
THUNDERSTORMS. HIGH TEMPERATURES SUNDAY SHOULD BE A TOUCH COOLER
THAN SATURDAY, BUT STILL AVERAGING AROUND 10 DEGREES ABOVE NORMAL.
PERSISTENT LOW-LEVEL EAST-NORTHEAST FLOW WILL BRING SOME DRIER
AIR INTO THE AREA ON MONDAY. OTHERWISE THERE IS LITTLE IF ANY
CHANGE TO THE PATTERN AND HIGHS ON MONDAY SHOULD REMAIN ABOVE
NORMAL AND COMPARABLE TO SUNDAY.
THE OMEGA BLOCK WILL SETTLE EQUATORWARD HEADING INTO TUESDAY AS THE
LAKE WINNIPEG UPPER HIGH MOVES INTO THE NORTHERN PLAINS AND A LARGE
DEEP UPPER LOW DIGS SOUTHWARD FROM QUEBEC AND TAKES RESIDENCE OVER
THE MID-ATLANTIC/NEW ENGLAND REGION. THE EXPANSE OF THE NERN UPPER
LOW WILL BRING HEIGHT FALLS ALOFT TO OUR REGION AND DRIVE A WEST-
EAST COLD FRONT ACROSS THE AREA TUESDAY-TUESDAY NIGHT. DEEP MOISTURE
AND INSTABILITY MAY BE LACKING A BIT WITH THE COLD FROPA, BUT AT
THIS TIME FRAME THERE IS ENOUGH SUPPORT FOR AT LEAST A LOW CHANCE OF
SHOWERS AND THUNDERSTORMS.
THE FRONT WILL BRING COOLER AND MUCH DRIER AIR STARTING WITH THE
FROPA TUESDAY, BUT ESPECIALLY WEDNESDAY AND THURSDAY. THE LATEST
FORECAST HAS TRENDED COOLER, BUT WE WILL LIKELY SEE ADDITIONAL
LOWERING OF THE HIGH TEMPS IN UPCOMING FORECASTS THE NEXT FEW DAYS.
THE 02/00Z ENSEMBLE CLUSTER ANALYSIS SUGGESTS THAT OUR CURRENT
FORECAST HIGH TEMPERATURES ARE PROBABLY A BIT ON THE HIGH SIDE BY 5
DEGREES OR SO. ONE CLUSTER WHICH HAS A DEEPER NE TROF AND LOWER
HEIGHTS INTO THE MID MS VALLEY HAS MEAN HIGH TEMPERATURES AS MUCH AS
10 DEGREES COOLER WITH HIGHS ONLY IN THE MID-UPPER 70S WEDNESDAY-
THURSDAY.
GLASS
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 630 AM CDT FRI JUN 2 2023
LIGHT EASTERLY WINDS WILL CONTINUE THROUGH THE TAF PERIOD WITH
DIURNAL CUMULUS POSSIBLE IN THE AFTERNOON. THERE IS A CHANCE OF
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS IN CENTRAL MO
THROUGH THE AFTERNOON AND EARLY EVENING HOURS. OTHERWISE, VFR FLIGHT
CONDITIONS WILL PERSIST.
MMG/GLASS
LSX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
IL...NONE.
WFO LSX
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