481
FXUS63 KDTX 190800
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
400 AM EDT FRI JUN 19 2026
KEY MESSAGES
- MAINLY DRY TODAY WITH A FEW ISOLATED SHOWERS POSSIBLE OVER THE
THUMB THIS AFTERNOON.
- SCATTERED SHOWERS ARE POSSIBLE SATURDAY MORNING, AND THEN AGAIN
SATURDAY AFTERNOON.
- BROADER COVERAGE OF SHOWERS AND THUNDERSTORMS POSSIBLE SUNDAY
EVENING AND OVERNIGHT, ESPECIALLY SOUTH OF I-94.
- COOLER THAN NORMAL TEMPERATURES ARE EXPECTED THROUGH AT LEAST THE
MIDDLE OF NEXT WEEK.
DISCUSSION
THE 990 MB SURFACE LOW PRESSURE SYSTEM THAT PRODUCED ACTIVE WEATHER
WEDNESDAY INTO EARLY THURSDAY WILL CONTINUE TRACKING EASTWARD ALONG
THE ST. LAWRENCE RIVER TODAY, EXITING INTO THE CANADIAN MARITIMES.
GIVEN ITS MERIDIONALLY EXPANSIVE CYCLONIC FIELD, DYNAMIC ASCENT WILL
STILL BE PRESENT OVER PORTIONS OF SOUTHEAST MICHIGAN. FORECAST
SOUNDINGS INDICATE PERHAPS JUST ENOUGH MID-LEVEL COOLING WITHIN THE
NORTHWEST FLOW REGIME TO SUPPORT WEAK SBCAPE, ON THE ORDER OF 100-
250 J/KG. THIS INSTABILITY INCREASES, JUST AS MID-LEVEL GEOPOTENTIAL
HEIGHTS REVERSE AND BEGIN TO RISE WITH THE ARRIVAL OF SHORTWAVE
RIDGING. THIS SHOULD ACT TO INHIBIT ASCENT, BUT CHOSE TO INCLUDE
MENTIONS OF ISOLATED THUNDERLESS LIGHT SHOWERS ACROSS THE GREATER
THUMB REGION FROM 18-22Z. IT'S ALSO POSSIBLE THAT THE DRY COLUMN
WILL FAVOR VIRGA WITH ANY SHOWERS THAT DO MATERIALIZE. HYDROMETEORS
FACE A DIFFICULT PATH FOR SURVIVAL, FALLING THROUGH A NEARLY 5 KFT
INVERTED-V SHAPED BOUNDARY-LAYER, SO NO QPF WAS ADDED. GUIDANCE
CONTINUES TO RUN A BIT WARM, RELATIVE TO EXPECTED HIGHS, GIVEN 850
MB TEMPERATURES AROUND 8C. HOWEVER, UNIMPEDED INSOLATION DUE TO NEAR
ZERO CLOUD FRACTION SHOULD OFFER A DIABATIC BOOST. HIGHS IN THE LOW
70S OUGHT TO BE THE NORM, WITH MID 70S POSSIBLE FROM METRO DETROIT
SOUTH. SURFACE RIDGING BRIEFLY BUILDS IN EARLY TONIGHT, BACKING
WINDS TOWARD THE WSW.
LOW AMPLITUDE CYCLONIC SHORTWAVE PERTURBATION EMBEDDED WITHIN THE
LONGWAVE PATTERN TRANSITS LOWER MICHIGAN EARLY SATURDAY MORNING,
ALONG WITH A FAINT SURFACE REFLECTION. RESIDUAL PACIFIC MOISTURE
SHOULD SUFFICE IN THE MAINTENANCE OF REMNANT NOCTURNAL CONVECTION,
BUT THIS ACTIVITY MOVES INTO A LESS FAVORABLE AIRMASS. MUCH OF THE
ZONALLY ADVECTED THETA-E WILL GO TOWARDS TOP-DOWN SATURATION OF A
COLUMN CHARACTERIZED BY AN INITIAL PWAT OF AROUND 0.60 INCHES. WHILE
A MORNING LIGHTNING STRIKE OR TWO CANNOT BE RULED OUT, FORECAST
SOUNDINGS ARE NOT SUPPORTIVE OF MEANINGFUL SHEAR OR INSTABILITY. THE
MORNING ACTIVITY DOES IMPROVE ANTECEDENT CONDITIONS FOR DIURNAL
CONVECTION SATURDAY AFTERNOON. SHOWERS AND PERHAPS A FEW
THUNDERSHOWERS ARE ONCE AGAIN FAVORED OVER THE NORTHEASTERN PART OF
THE FORECAST AREA (GENERALLY NORTH OF I-69), BETTER POSITIONED
WITHIN THE THERMAL TROUGH ALOFT. SIMILARLY COOL AND DRY SATURDAY
NIGHT WITH ENOUGH CLEARING AND LOWS IN THE 50S.
DIFFUSE HIGH PRESSURE EMERGES OVER THE LOWER PENINSULA SUNDAY
MORNING WHILE A SPEED MAX EJECTS ACROSS THE PLAINS AND INTO THE OHIO
VALLEY, LIKELY SUSTAINING AN MCS. THE TIME-FRAME FOR ARRIVAL IS
GENERALLY STILL OUT OF THE HI-RES WINDOW, BUT MID-RANGE 00Z
DETERMINISTICS LARGELY AGREE IN THE SHAPE AND SPEED OF THIS WAVE
ACROSS THE OHIO VALLEY. MAIN QUESTION NOW IS HOW FAR NORTH DOES THE
WAVE TRACK, AND BY EXTENSION, HOW FAR INTO SOUTHERN LOWER DOES ANY
ISENTROPIC/OVERRUNNING PRECIPITATION REACH. THE SURFACE WARM FRONT
WILL STRUGGLE TO LIFT BEYOND THE STATE-LINE, AND LOW-LEVEL MOISTURE
TRANSPORT WILL BE FIGHTING DRIER AIR FILTERING DOWN FROM NORTHERN
MANITOBA HIGH PRESSURE. LATEST POPS APPEAR A BIT BULLISH AT THIS
JUNCTURE, PARTICULARLY THE LIKELIES NORTH OF I-94. FURTHER SOUTH,
THE ENVIRONMENT WILL BE MORE FAVORABLE FOR HIGHER RAINFALL AMOUNTS.
COOLER THAN NORMAL TEMPERATURES ARE EXPECTED TO CONTINUE THROUGH THE
MIDDLE OF NEXT WEEK WITH DRIER CONDITIONS BY TUESDAY, FOLLOWED BY A
SHOWERY DAY WEDNESDAY.
MARINE
WEST TO NORTHWEST FLOW WILL HOLD TODAY IN THE WAKE OF A STRONG LOW
PRESSURE SYSTEM WHICH WILL SUPPORT SOME BREEZY CONDITIONS FOR
PORTIONS OF THE GREAT LAKES, PARTICULARLY ACROSS NORTHERN LAKE HURON
GIVEN THE MORE FAVORABLE FETCH. A RIDGE OF HIGH PRESSURE WILL BUILD
IN TONIGHT THROUGH TOMORROW MORNING WHICH WILL RELAX WIND SPEEDS AND
SUPPORT LIGHTER WINDS THROUGH THE WEEKEND. RAIN SHOWERS WILL BE
POSSIBLE TOMORROW AS AN UPPER-LEVEL DISTURBANCE MOVES IN, ALONG WITH
A LOW CHANCE FOR AN ISOLATED THUNDERSTORM. ADDITIONAL CHANCES FOR
RAIN AND THUNDERSTORMS WILL ENTER SUNDAY NIGHT TO MONDAY MORNING AS
A LOW PRESSURE SYSTEM TRAVELS THROUGH THE OHIO VALLEY AND SOUTHERN
GREAT LAKES. THIS SYSTEM WILL BRING ELEVATED WIND GUSTS THROUGH LAKE
ERIE AND LAKE ST. CLAIR, WHERE THE PRESSURE GRADIENT IS STRONGEST.
PREV DISCUSSION
ISSUED AT 1157 PM EDT THU JUN 18 2026
AVIATION...
THERE REMAINS SOME POTENTIAL FOR ADDITIONAL POCKETS OF VFR CLOUD TO
FUNNEL THROUGH AT TIMES OVERNIGHT AS A MINOR MID LEVEL WAVE LIFTS
THROUGH. DAYTIME HEATING WILL AGAIN OFFER A SUPPORTIVE ENVIRONMENT
FOR A SCATTERED TO BROKEN COVERAGE OF VFR CUMULUS FOR THE AFTERNOON
HOURS FRIDAY. THIS WILL OCCUR WITHIN GUSTY WESTERLY CONDITIONS, AS
DEEPER MIXING AGAIN YIELDS GUST POTENTIAL INTO THE 25 KNOT RANGE FOR
THE AFTERNOON.
D21/DTW CONVECTION...NO THUNDERSTORMS EXPECTED.
DTW THRESHOLD PROBABILITIES...
* MEDIUM FOR CEILINGS AT OR BELOW 5 KFT THIS EVENING.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
DISCUSSION...KGK
MARINE.......AM
AVIATION.....MR
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