497
FXUS63 KAPX 200541
AFDAPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GAYLORD MI
141 AM EDT SUN JUL 20 2025
KEY MESSAGES
- SHOWERS AND THUNDERSTORMS TONIGHT/LOCALLY HEAVY RAINFALL AND
SEVERE WEATHER POTENTIAL.
- DRIER CONDITIONS EXPECTED SUNDAY WITH SEASONABLE
TEMPERATURES.
- TRENDING WARMER AND MORE HUMID BEYOND MONDAY; HOW WARM MIDWEEK
WILL GET DEPENDS ON THE EVOLUTION OF THE NEXT BULLET POINT...
- INCREASING PRECIPITATION CHANCES STARTING TUESDAY NIGHT.
SHORT TERM /THROUGH THIS AFTERNOON/
ISSUED AT 254 PM EDT SAT JUL 19 2025
PATTERN SYNOPSIS/FORECAST: FAIRLY TYPICAL SUMMER PATTERN ACROSS THE
CONUS...BROAD RIDGING ACROSS THE SOUTHERN HALF (SAVE FOR A WEAK
UPPER LOW OVER SOUTHERN CALIFORNIA)...AND MORE ZONAL FLOW ACROSS THE
NORTHERN TIER OF STATES. CORE OF THE STRONGEST FLOW (100KT JET
STREAK) CUTTING ACROSS THE GREAT LAKES. UPPER LOW OVER BRITISH
COLUMBIA/ ALBERTA...AND A PROMINENT SHORT WAVE TROUGH DIGGING
SOUTHEAST OVER NORTHWEST ONTARIO. DEEP LAYER MOISTURE ALSO GETTING
PULLED BACK INTO THE UPPER LAKES WITH PRECIPITABLE WATER VALUES
>1.50 INCHES ACROSS SOUTHERN WISCONSIN/SOUTHERN LAKE MICHIGAN...LOW
LEVEL THETA-E RIDGE EXTENDS FROM NEBRASKA INTO SOUTHWEST WISCONSIN.
A COUPLE AREAS OF WEAK SURFACE HIGH PRESSURE SURROUND THE REGION:
1021MB HIGH OVER NEW ENGLAND RIDGING BACK ACROSS THE REGION...AND A
1018MB HIGH OVER MANITOBA/SASKATCHEWAN. BROAD AREA OF LOW PRESSURE
OVER THE CENTRAL PLAINS/MIDWEST...WARM FRONT RUNS NORTHWEST-
SOUTHEAST ACROSS IOWA/SOUTHERN ILLINOIS AND TURNS EASTWARD ALONG THE
OHIO RIVER. ALSO A HINT OF A WARM FRONT ACROSS SOUTHWEST
WISCONSIN/SOUTHWEST LOWER MICHIGAN...AND A SURFACE TROUGH AXIS
ACROSS NORTHERN WISCONSIN/UPPER MICHIGAN.
FRONTAL BOUNDARY WILL BE IN THE VICINITY OF NORTHERN LOWER LATE THIS
AFTERNOON WHILE NORTHWEST ONTARIO SHORT WAVE TROUGH SLIPS PAST
NORTHERN LAKE SUPERIOR (ALONG WITH A TRAILING SECONDARY PV ANOMALY
OVERNIGHT). FRONT WILL ALSO GET NUDGED SOUTH TONIGHT AS HIGH
PRESSURE TO THE NORTHWEST BUILDS INTO THE UPPER LAKES FOR SUNDAY.
PRIMARY FORECAST CONCERNS:
SHOWERS AND THUNDERSTORMS TONIGHT/LOCALLY HEAVY RAINFALL AND SEVERE
WEATHER POTENTIAL: SHOWERS AND SOME EMBEDDED CONVECTION HAVE BEEN
MORE NUMEROUS ACROSS EASTERN UPPER AND TIP OF THE MITT THROUGH EARLY
AFTERNOON...WITH MORE SCATTERED NORTH-SOUTH ALIGNED ACTIVITY FARTHER
SOUTH. STARTING TO GET BETTER LOW LEVEL MOISTURE/THETA-E ADVECTION
INTO NORTHWEST LOWER WHICH HAS BEEN AIDING ACTIVITY...ALONG WITH A
700MB SHORT WAVE TROUGH CROSSING WISCONSIN. WILL BE WATCHING
SURFACE BASED INSTABILITY TRENDS THROUGH THE REMAINDER OF THE
AFTERNOON; NOT A HUGE AMOUNT OF INSTABILITY ANTICIPATED GIVEN HOW
WARM IT IS ALOFT (500-1000J/KG) THOUGH DEEP LAYER SHEAR ISN'T BAD (0-
6KM ~35KTS THOUGH IT IS BETTER FARTHER NORTH CLOSER TO STRONGER MID
LEVEL FLOW BUT FARTHER AWAY FROM INSTABILITY). SO STILL SOME GUSTY
WIND POTENTIAL EVENT FOR THE AFTERNOON/EARLY EVENING MOSTLY SOUTH OF
M-32...SPC HAS A 2% TORNADO OUTLOOK SOUTH OF M-72/EAST OF US-131. 0-
3KM MLCAPE FORECAST PRETTY ROBUST THIS EVENING...BUT SHEAR BELOW 1KM
IS MARGINAL. PRECIPITABLE WATER VALUES > 1.50 INCHES ALSO SUPPORTS
HEAVY DOWNPOURS AND LOCALLY HEAVY RAINFALL ESPECIALLY IF SOME ECHO
TRAINING CAN COME INTO PLAY...THOUGH AT THIS POINT NOT EXPECTING
THINGS TO GET TOO OUT OF HAND.
DRIER CONDITIONS EXPECTED SUNDAY WITH SEASONABLE TEMPERATURES:
ANTICIPATE THAT WE WILL START THE DAY WITH SOME FOG ESPECIALLY
ACROSS EASTERN UPPER AND PERHAPS THE TIP OF THE MITT
COUNTIES...AND PERHAPS SOME LINGERING ST ACROSS CENTRAL LOWER.
BUT OUTSIDE OF THAT SHOULD BE A NICER DAY WITH MORE SUNSHINE AND
HIGHS JUST A SHADE UNDER MID JULY NORMALS.
LONG TERM /TONIGHT THROUGH SATURDAY/
ISSUED AT 254 PM EDT SAT JUL 19 2025
DAYS 2-3 (MONDAY-TUESDAY): WARMING TREND STARTS MONDAY WITH THE
BEGINNINGS OF A BURGEONING UPPER LEVEL RIDGE SETTING UP ACROSS THE
MIDDLE/LOWER MISSISSIPPI AND OHIO VALLEYS FOR THIS WEEK. HIGH
PRESSURE OVER THE GREAT LAKES MONDAY SHIFTS EAST TUESDAY ALLOWING
FOR A MORE SOUTHERLY RETURN FLOW TO SET UP THOUGH HUMIDITY NOT
EXPECTED TO BE TOO BAD THROUGH TUESDAY AFTERNOON. DEVELOPING
RIDGE AND MICHIGAN BEING ON THE NORTHERN PERIPHERY OF IT SETS
UP THE POTENTIAL FOR RIDGE RUNNING MCSS HEADING INTO WEDNESDAY.
DAYS 4-5 (WEDNESDAY-THURSDAY): WARM UPPER LEVEL RIDGING EXPECTED
TO TAKE HOLD OVER THE MIDDLE/LOWER MISSISSIPPI VALLEY AND OHIO
VALLEY...597DAM 500MB HEIGHTS OVER THE OHIO VALLEY THURSDAY.
MIDWEEK PERIOD SHAPING UP TO BE A WETTER PERIOD UNDER THE
BUSINESS END OF THE LOW LEVEL JET...THIS WILL ALSO PLAY HAVOC
WITH FORECAST TEMPERATURES AS WEDNESDAY AND THURSDAY COULD BE
WARM AND SULTRY WITH INCREASING PROBABILITIES OF HIGHS EXCEEDING
90F ACROSS NORTHERN LOWER. BUT FORECAST HIGHS ARE NOTABLY ON
THE LOWER END OF THE FORECAST PROBABILITY DISTRIBUTION AND AS
USUAL FOR US IN THIS TYPE OF PATTERN THE EVOLUTION OF CLOUD
COVER AND PRECIPITATION WILL BE THE OVERRIDING FACTORS REGARDING
HOW WARM WE GET.
DAYS 6-7 OUTLOOK (FRIDAY-SATURDAY): INITIAL LOOK AT THE START OF
NEXT WEEKEND SUGGESTS PERHAPS A SMALL MODERATION IN TEMPERATURES
BUT STILL LOOKS WARM (OR AT LEAST TYPICAL SUMMER WARMTH). A
TREND TOWARD A DRIER PERIOD ALSO APPEARS TO BE IN THE OFFING.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 137 AM EDT SUN JUL 20 2025
LOW CIGS AND PATCHY BR/FG THROUGH THE REST OF TONIGHT, MVFR TO
IFR GENERALLY. ANY SHRA/RA HAS MOVED OUT OF THE REGION,
ALTHOUGH AN AREA OF DZ OR TWO CANNOT BE RULED OUT. CONDITIONS
RETURN TO VFR BY THE EARLY TO MID MORNING HOURS TODAY, WITH
QUIET AND DRY WEATHER THE REST OF THE PERIOD. WINDS NORTH TO
NORTHWEST THROUGH THE DAY, 5 TO 15 KTS.
APX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
MARINE...NONE.
SHORT TERM...JPB
LONG TERM...JPB
AVIATION...JLD
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