Area Forecast Discussion
Issued by NWS St. Louis, MO

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FXUS63 KLSX 052052
AFDLSX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ST LOUIS MO
352 PM CDT SUN JUL 5 2015

.SHORT TERM: (TONIGHT THROUGH MONDAY)
ISSUED AT 331 PM CDT SUN JUL 5 2015

THE EVENING LOOKS RATHER TRANQUIL ACROSS THE REGION WITH
DISSIPATING DIURNAL CU AND A FEW HIGH CLOUDS FILTERING ACROSS THE
AREA. THE RETURN OF SOUTHERLY LOW LEVEL FLOW HAS LEAD TO WARMER
TEMPERATURES TODAY AND GREATER MOISTURE. OVERNIGHT THERE ARE
INDICATIONS BY THE NAM AND ESPECIALLY THE RAP THAT WE MAY SEE SOME
SPOTTY ELEVATED SHOWERS AND THUNDERSTORMS FROM SOUTH CENTRAL MO
INTO EAST CENTRAL AND SOUTHEAST MO IN THE NEAR DAWN HOURS, THEN
SHIFTING EAST ON MONDAY MORNING. A VERY WEAK PETURBATION IN THE
NORTHWEST FLOW ALOFT, AND MORE IMPORTANTLY VEERING AND STRENGTHENING
LOW-LEVEL FLOW IN THE 3000-7000 FT LAYER AND ATTENDANT THERMAL AND
MOISTURE ADVECTION COULD GENERATE SOME ACTIVITY IN THE 07-15Z TIME
FRAME. I HAVE ADDED SOME SLIGHT CHANCE POPS TO THE FORECAST WITH
THIS IN MIND. OTHERWISE MILDER TEMPERATURES ON TAP TONIGHT AND A
RATHER WARM DAY IS ON SCHEDULE FOR MONDAY. THE MODELS NOW ALL HAVE
A BIT SLOWER PROGRESS WITH THE COLD FRONT, NOT ENTERING FAR
NORTHWEST MO UNTIL THE 21-00Z TIME FRAME. GIVEN THIS SLOWER SPEED
AND LESSER CLOUDS EXPECTED WITH THE FORECAST WAA REGIME, I EXPECT
TEMPERATURES WELL INTO THE 80S WITH A FEW SPOTS AROUND 90. WE
COULD ALSO SEE SOME SPOTTY DIURNALLY DRIVEN PULSE STORMS IN THE
AFTERNOON IN THE BROAD WARM MOIST AND UNSTABLE WARM SECTOR.

GLASS

.LONG TERM: (MONDAY NIGHT THROUGH NEXT SUNDAY)
ISSUED AT 331 PM CDT SUN JUL 5 2015

MONDAY NIGHT INTO WEDNESDAY STILL LOOKS LIKE A WET AND STORMY
PATTERN WITH WIDESPREAD MULTI-DAY AVERAGE RAINFALL TOTALS OF 2-4
INCHES. THE BIGGEST ISSUE IS JUST WHERE THE HEAVIEST RAINFALL MAY
FOCUS WITH THE MODELS HAVING SOME GROWING DIFFERENCES WITH TIME
FROM TUESDAY AND BEYOND WHERE THE FRONT MAY LIE. THE ECMWF HAS THE
MOST AGRESSIVE SOUTHWARD PUSH EARLY ON THEN WAVERS THE FRONT
THROUGH THE AREA LATE THIS WEEK. ALTERNATIVELY THE GFS AND NAM
BOTH DON`T MOVE THE FRONT AS FAR SOUTH AND THEN WAVER IT TUESDAY
NIGHT INTO WEDNESDAY AS SURFACE WAVES MOVE ALONG IT, FINALLY
PUSHING NORTH OF THE CWA BY THURSDAY EVENING. THE REGION SPANNING
THE FRONTAL ZONE WILL BE VERY MOIST AND A BROAD REGION OF DEEP LOW
LEVEL CONVERGENCE WILL FOCUS WIDESPREAD SHOWERS AND THUNDERSTORMS
WITH POTENTIAL FOR HEAVY RAIN. WE MAY ULTIMATELY NEED A FLASH
FLOOD WATCH ONCE WE CAN PIN DOWN THE REGION A BIT BETTER.

LOOKS LIKE PRECIPITATION CHANCES WILL DECREASE INTO NEXT WEEKEND
WITH A RETURN OF SUMMER HEAT.

GLASS

&&

.AVIATION:  (FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1035 AM CDT SUN JUL 5 2015

AREA OF LOW PRESSURE WILL CONTINUE TO MOVE EAST THROUGH THE
TENNESSEE VALLEY WITH HIGH PRESSURE STRETCHING FORM THE GREAT
LAKES TO THE RED RIVER VALLEY. AS EVERYTHING CONTINUES TO MOVE
EAST A SOUTHERLY WIND WILL GRADUALLY INCREASE INTO MONDAY.
IFR/MVFR STRATUS MOVED INTO SOUTH CENTRAL MO OVERNIGHT WITH THE
WEAK SOUTH WIND. THIS WILL HAVE TO BE WATCHED AS IT MAY MAKE IT
INTO COU. OTHERWISE MOSTLY VFR FORECAST WITH SOME MORINING FOG AND
HAZE.

SPECIFICS FOR KSTL: CONTINUED MOSTLY VFR WITH SOME MORNING FOG AND
HAZE ONCE AGAIN AS THE LIGHT SOUTHERLY WIND WILL LIKELY NOT BE
STRONG ENOUGHT TO STOP IN. NAM AND GFS DEVELOP SCATTERED SHOWERS
AND STORMS MONDAY AFTERNOON, BUT GIVEN THIS IS THE LAST 6 HOURS
OF THE PERIOD, AND A VICINITY WOULD BE ALL THIS IS NEEDED, WILL
LEAVE DRY.

JPK

&&

.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&

$$

WFO LSX


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