Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KDTX 250756
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
356 AM EDT SAT JUL 25 2015

.SHORT TERM...TODAY AND TONIGHT

A WEAKENING COLD FRONT WILL PASS THROUGH LOWER MI TODAY BRINGING THE
CHANCE OF SHOWERS AND THUNDERSTORMS. THE PARENT LOW FOR THE FRONT IS
LOCATED OVER NORTHERN ONTARIO AND WILL CONTINUE SLOWLY EASTWARD
THROUGH THE DAY WHILE THE FRONT PIVOTS AROUND IT AND THROUGH THE
AREA. THE TIMING OF THE FRONT PASSAGE WILL BE IN THE AFTERNOON
AROUND 18-00Z...DURING PEAK HEATING. THIS WILL OF COURSE FAVOR STORM
DEVELOPMENT AS SFC TEMPS REACH INTO THE LOW/MID 80S WITH DEWPOINTS
LOOKING TO REACH 70. WILL CONTINUE WITH CHANCE POPS FOR SHOWERS AND
THUNDERSTORMS TODAY WITH THE MAIN ADJUSTMENT COMING IN THE TIMING OF
THE PRECIP...ELIMINATING ALL POPS BEFORE 14Z AS THE LINE OF
CONVECTION IS STILL FAR TO THE WEST OVER CENTRAL WI. DETAILS OF THE
SETUP TO FOLLOW...

THE UPPER LEVEL JET MAX HAS WORKED ITS WAY ACROSS THE MS RIVER AND
WILL REACH MID MI THIS MORNING. MODELS ALL SHOW THIS TO WEAKEN
THROUGH THE DAY FROM 100 KNOTS DOWN TO AROUND 70 KNOTS. THIS WILL
ALLOW DECENT SHEAR AHEAD OF THE FRONT WITH 0-3KM VALUES AROUND 25-30
KNOTS WHICH WILL BE ENOUGH TO TRY TO ORGANIZE SOME STORMS THAT CAN
DEVELOP. THIS WILL HELP COMPENSATE SOMEWHAT FOR THE LACK OF NOTABLE
FRONTAL FORCING ANYWHERE ALONG THE FRONT. AS HAS BEEN THE CASE MUCH
OF THE CONVECTIVE SEASON...MID LEVEL LAPSE RATES LOOK TO BE VERY
WEAK ONCE AGAIN BUT LL LAPSE RATES WILL BE PRETTY GOOD AS SFC TEMPS
QUICKLY RISE INTO THE MID 80S ONCE AGAIN. CAPE WILL ALSO BE
FAVORABLE AS A CORRIDOR OF 70 DEGREE DEWPOINTS AHEAD OF THE FRONT
SLIDES THROUGH THE AREA. A FAIR VALUE LOOKS TO BE AROUND 1500-2000
J/KG AVAILABLE THIS AFTERNOON. BEST CHANCES FOR ORGANIZED...POSSIBLE
STRONG TO SEVERE...STORMS WILL BE OVER THE SOUTHERN AND EASTERN
LOCATIONS AS THEY WILL HAVE SEVERAL ADDITIONAL HOURS OF HEATING TO
WORK WITH. IN ADDITION THERE APPEARS TO BE A SECONDARY COLD FRONT OR
SHORTWAVE SLIDING IN THIS AFTERNOON WHICH MAY PROVIDE A LITTLE EXTRA
BOOST LATER IN THE DAY. FOR ANY ONE LOCATION THERE LOOKS TO BE
AROUND A 3-5 HOUR WINDOW WHERE THESE ISOLATED TO SCATTERED STORMS
COULD IMPACT THEM. MBS WILL START EARLY IN THE DAY AS THE FRONT
APPROACHES AROUND 14Z...WHICH WILL LIMIT STRENGTH OF THESE
STORMS...WITH DTW HOLD OFF TIL CLOSER TO 18-20Z FOR A START TIME.
ALL ACTIVITY LOOKS TO PASS TO THE SOUTH/EAST BY 00Z. ANY ORGANIZED
STORM WILL HAVE THE POTENTIAL TO PRODUCE 60 MPH GUSTS AND/OR LARGE
HAIL. SPC HAS SOUTHEAST LOWER MI INCLUDED IN THE MARGINAL RISK AREA
WHICH SEEMS REASONABLE FOR THE SETUP.

ONCE THE FRONT PASSES...HIGH PRESSURE WILL CLEAR OUT THE CLOUDS FOR
THE OVERNIGHT BUT TEMPS WILL REMAIN ELEVATED AS THE POST FRONTAL
AIRMASS IS SPORTING DEWPOINTS IN THE LOW 60S.

&&

.LONG TERM... SUNDAY THROUGH FRIDAY

A TEMPORARY DIP IN THE UPPER HEIGHT FIELD OVER THE NEXT 24 HOURS
WILL HELP EASE THE ATTENDANT WEAK FRONT INTO THE OHIO VALLEY BY
EARLY SUNDAY.  POST-FRONTAL ENVIRONMENT SUNDAY WILL BE MORE NOTABLE
FOR A REDUCTION IN HUMIDITY RELATIVE TO TODAY...WITH NO REAL CHANGE
EXPECTED IN THE TEMPERATURES.  THE DRIER AND MORE STABLE CONDITIONS
AS HIGH PRESSURE SLIDES THROUGH WILL TRANSLATE INTO A HIGH DEGREE OF
SUNSHINE.  THIS INSOLATION POTENTIAL INTO A DRIER AND MODESTLY MIXED
PROFILE FAVORS A GREATER DIURNAL TEMPERATURE RESPONSE...AND WILL
NUDGE HIGHS UP A COUPLE DEGREE ACCORDINGLY FOR SUNDAY AFTERNOON.
GOING FORECAST HOLDING FIRM WITH EXPECTATIONS THAT CONVECTIVE
ACTIVITY THAT EMERGES ALONG THE FRONTAL ZONE WILL REMAIN SOUTH OF
THE BORDER SUNDAY AND SUNDAY NIGHT.

PREDOMINANT SOUTHERN CONUS UPPER RIDGING WILL UNDERGO STEADY
AMPLIFICATION INTO THE GREAT LAKES THROUGH THE EARLY WEEK PERIOD.
THE ACCOMPANYING RISE IN MEAN THICKNESSES THROUGHOUT THE COLUMN WILL
TRANSLATE INTO SEVERAL DAYS OF ABOVE NORMAL WARMTH.  WARMEST
CONDITIONS CENTERED ON THE TUESDAY AND WEDNESDAY PERIODS AS THE
UPPER RIDGE AXIS PIVOTS OVERHEAD...850 MB TEMPERATURES REACHING INTO
THE 18 TO 20C RANGE DURING THIS TIME.  THIS WILL SUPPORT READINGS IN
THE VICINITY OF 90 DEGREES BOTH DAYS.  CONVECTIVE POTENTIAL HAMPERED
BY THE INCREASING MID LEVEL TEMPERATURES AND LACK OF SUFFICIENT
FORCING BOTH MONDAY AND TUESDAY.  NEXT FRONTAL PASSAGE CENTERED
WITHIN THE WEDNESDAY AND WEDNESDAY NIGHT PERIODS...AS THE SOUTHERN
EXTENT OF HEIGHT FALLS ASSOCIATED WITH A DEEPENING WAVE LIFTING INTO
SOUTHERN CANADA ENTERS THE GREAT LAKES.  THIS WILL PROVIDE THE NEXT
OPPORTUNITY FOR THUNDERSTORM DEVELOPMENT.  COOLER...OR A TRANSITION
BACK TOWARD NORMAL...TEMPERATURES IN THE WAKE OF THE FRONT FOR THE
END OF THE WORK WEEK.

&&

.MARINE...

A COLD FRONT ACROSS LAKE HURON AND LOWER MICHIGAN TODAY.  THIS FRONT
WILL BRING A CHANCE OF THUNDERSTORMS TO ALL MARINE AREAS.   MODERATE
SOUTHWESTERLY WINDS IN ADVANCE OF THIS FRONT...SHIFTING TO NORTH
POST FRONT THROUGH EARLY TONIGHT.  WEAK HIGH PRESSURE SETTLING
ACROSS THE REGION WILL BRING FAVORABLE MARINE CONDITIONS SUNDAY
THROUGH EARLY NEXT WEEK.

&&

.AVIATION...ISSUED 1147 PM EDT FRI JUL 24 2015

MAINLY CLEAR SKIES EARLY THIS MORNING OVER SOUTHEAST MICHIGAN.
COLD FRONT OVER WESTERN GREAT LAKES ATTEMPTING TO BECOME MORE
ACTIVE...BUT ACTIVITY IS EXPECTED TO DIMINISH AS IT PUSHES INTO
LOWER MICHIGAN DUE TO DRIER AIR IN PLACE AND MORE STABLE AIRMASS.
NONE-THE-LESS...WILL CONTINUE TO HIGHLIGHT A FEW LEFTOVER SHOWERS
IMPACTING MBS/FNT DURING THE MORNING HOURS. HIGH MVFR/LOW VFR
CEILINGS ARE EXPECTED ALONG THE COLD FRONT...WHICH WILL SLOWLY
SINK SOUTH DURING THE DAY. DAYTIME INSTABILITY WILL BRING AN
INCREASING CHANCE OF THUNDERSTORMS DEVELOPING DURING THE AFTERNOON
HOURS...MAINLY ACROSS THE SOUTHERN TAF SITES...WHERE A PROB30 FOR
THUNDERSTORMS WILL REMAIN IN PLACE...ALTHOUGH OVERALL COVERAGE IS
NOT EXPECTED TO BE MORE THAN SCATTERED. NORTHWEST TO NORTHEAST
WINDS BEHIND THE FRONT ARE EXPECTED TO BE LIGHT...THUS NOT A HUGE
PUSH OF DRY AIR BEHIND THE FRONT...AND THUS SOME CONCERN THE
CLEARING FROM NORTH TO SOUTH COULD BE A BIT SLOWER THAN FORECASTED.

FOR DTW...COLD FRONT LOOKS TO BE MOVING THROUGH DURING PEAK HEATING
OF SATURDAY...WARRANTING A PROB30 FOR TSTORMS 19-22Z. UNCERTAINTY
REGARDING EXTENT OF MVFR BASED CLOUD COVER WITH FROPA...AND WILL
CONTINUE TO FAVOR PREVAILING LOW VFR CEILINGS...UNTIL OBSERVATIONAL
TRENDS SUPPORT OTHERWISE. SOUTHWEST WINDS WILL SLIGHTLY EXCEED 10
KNOTS AHEAD OF THE FRONT...WITH LITTLE (UNDER 10 KNOTS) NORTHERLY
PUSH BEHIND THE FRONT AROUND 00Z SUNDAY.

//DTW THRESHOLD PROBABILITIES...

* MEDIUM FOR CIGS AOB 5KFT SATURDAY AFTERNOON AND EVENING.

* LOW FOR THUNDERSTORMS SATURDAY AFTERNOON

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&

$$

SHORT TERM...DRK
LONG TERM....MR
MARINE.......MR
AVIATION.....SF


YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.