Area Forecast Discussion
Issued by NWS Detroit/Pontiac, MI

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FXUS63 KDTX 260352
AFDDTX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
1152 PM EDT MON MAY 25 2015


.AVIATION...

UPSTREAM OBSERVATIONS ACROSS THE OHIO VALLEY SHOW SOME SEMBLANCE OF
LOW STRATUS LIFTING NORTHWARD. AREA OBSERVATIONS DO HOWEVER SUGGEST
MODEL SOLUTIONS MAY BE A LITTLE OVERZEALOUS WITH THE DEGREE OF LOW
LEVEL MOISTURE UPSTREAM. THIS WILL SUPPORT JUST A TEMPO FOR SOME
PERIODIC LOW CLOUDS TOWARD DAYBREAK TUES.

FOR DTW...THE ARRIVAL OF LOW CLOUDS /IF ANY/ SHOULD HOLD OFF UNTIL
11 OR 12Z. THE CHANCE FOR THUNDERSTORMS WILL INCREASE LATE TUES
AFTERNOON INTO TUES EVENING WITH THE APPROACH OF AN UPPER SHORT WAVE.

//DTW THRESHOLD PROBABILITIES...

* MEDIUM IN CIGS BELOW 5000 FT LATE TONIGHT AND TUESDAY MORNING.

* MEDIUM IN THUNDERSTORMS LATE TUESDAY AFTERNOON AND EVENING.

&&

.PREV DISCUSSION...ISSUED 847 PM EDT MON MAY 25 2015

UPDATE...

MID LEVEL SUBSIDENCE HAS BEEN BUILDING ACROSS SE MI THIS EVENING
AND IS INHIBITING ADDITIONAL SHOWER DEVELOPMENT. THIS SUBSIDENCE
WILL PERSIST THROUGH THE NIGHT AND WILL SUPPORT THE CURRENT DRY
FORECAST OVERNIGHT. A CONSIDERABLE AMOUNT OF HIGH CLOUDS ACROSS
LOWER MI AND THE POTENTIAL FOR SOME LOW STRATUS TO DEVELOP
OVER/ADVECT INTO SE MI WILL SUPPORT AN INCREASE IN CLOUD COVERAGE
AND A SLIGHT UPWARD ADJUSTMENT TO FORECAST MIN TEMPS TONIGHT.

PREV DISCUSSION...ISSUED 348 PM EDT MON MAY 25 2015

SHORT TERM...THIS AFTERNOON AND TONIGHT

VEERED LOW-LEVEL JET SITUATED OVERHEAD AS A WEAK SHORTWAVE LIFTS
ACROSS THE WESTERN GREAT LAKES THIS AFTERNOON. H7-H5 THETA-E
GRADIENT IS PRESENTLY SUPPORTING AN ARC OF SHOWERS THAT HAVE PROVEN
EFFICIENT IN MIXING DOWN ENVIRONMENTAL WINDS OF 50MPH WITH A LONE
REPORT OF 60MPH. LARGE SCALE SUPPORT FOR THIS PARTICULAR ROUND OF
SHOWERS WILL EXIT NORTHEAST BY 21Z. DRY SLOT INTRUSION HAS ERODED
THE MAJORITY OF LOW CLOUDS, PROVIDING A WINDOW WITHIN WHICH MODEST
RECOVERY MAY TAKE PLACE OVER THE NEXT COUPLE OF HOURS. STILL
QUESTION THE POTENTIAL FOR THUNDER, WITH NO CTG STRIKES OBSERVED VIA
NLDN YET TODAY, BUT THE POTENTIAL FOR UPDRAFTS OF EQUAL STRENGTH TO
THOSE ALREADY OBSERVED WILL EXIST AS DYNAMIC SHORTWAVE FORCING RACES
THROUGH THE AREA 20-00Z. THUS, THE FORECAST PROCEEDS WITH A HIGHER
CHC POP FOR A PARTIAL COVERAGE OF SHOWERS THROUGH 00Z WITH CONTINUED
POTENTIAL FOR 50 MPH WIND GUSTS OR PERHAPS AN ISOLATED 60 MPH.

VIGOROUS SHORTWAVE TRIGGERING TODAY`S SEVERE CONVECTIVE EPISODE IN
TEXAS/OKLAHOMA WILL LIFT NORTH THROUGH TONIGHT FORCING DOWNSTREAM
RIDGING. RESULTING SUBSIDENCE WILL FAVOR MOSTLY CLEAR SKIES THROUGH
THE NIGHT SAVE FOR PASSING CIRRUS DEBRIS. SOUTHERLY GRADIENT AT THE
SURFACE WILL ADVECT LOW-LEVEL MOISTURE AND ASSOCIATED CLOUDS FROM
THE OHIO VALLEY INTO THE SOUTHERN CWA BY SUNRISE. SOUTH WINDS WILL
HOVER AROUND 10 KTS THROUGH THE NIGHT WITH LOWS BOTTOMING OUT IN THE
MID 60S.

LONG TERM...

THE WARM AND MOIST AIRMASS NOW IN PLACE OVER THE AREA WILL PERSIST
INTO TUESDAY AND WEDNESDAY AS SOUTHWEST FLOW CONTINUES AROUND THE
WEST EDGE OF A PERSISTENT UPPER RIDGE CENTERED OVER THE SOUTHEAST
CONUS AND SOUTHWEST ATLANTIC OCEAN. THIS WILL MAINTAIN AFTERNOON
TEMPERATURES IN THE UPPER 70S TO LOWER 80S BOTH DAYS. THE MINIMUM
TEMPERATURES WILL REMAIN VERY MILD TUESDAY NIGHT WITH LOWS IN THE
MIDDLE 60S...BUT COOL SOME BY WEDNESDAY NIGHT AS A WEAK COLD FRONT
MOVES INTO THE AREA AS SHORTWAVE ENERGY EJECTING FROM A WESTERN AND
CENTRAL CONUS UPPER TROUGH BREAKS DOWN THE NORTH AND NORTHWEST PART
OF THE AFOREMENTIONED RIDGE AND ALLOWS FOR SLIGHTLY COOLER READINGS
OVER THE AREA.

SHOWER AND THUNDERSTORM CHANCES WILL ALSO INCREASE TUESDAY AND
TUESDAY NIGHT AS THE UPPER HEIGHTS LOWER IN RESPONSE SHORTWAVE
ENERGY LIFTING INTO THE REGION. WHILE THE SEVERE WEATHER POTENTIAL
IS NOT HIGH...A FEW STRONG STORMS WILL GUSTY WINDS WILL BE POSSIBLE
GIVEN THE INCREASINGLY UNSTABLE ENVIRONMENT. LINGER CONVECTIVE
ACTIVITY WILL ALSO AFFECT THE AREA WEDNESDAY AS THE COLD FRONT
SHIFTS THROUGH THE LOWER GREAT LAKES...WITH ACTIVITY THEN FADING
WEDNESDAY NIGHT AS COOLER...DRIER AIR BEGINS TO WORK INTO THE AREA.

DRY WEATHER WILL START OFF THE EXTENDED PERIOD AS HIGH PRESSURE
BUILDS SOUTH INTO THE REGION ON THURSDAY. DRY CONDITIONS WILL
CONTINUE THROUGH THURSDAY NIGHT BEFORE THE NEXT ROUND OF WET WEATHER
MOVES INTO THE AREA ON FRIDAY. RAIN SHOWER AND THUNDERSTORM CHANCES
WILL STICK AROUND THROUGH SATURDAY NIGHT AS A SERIES OF LOW PRESSURE
AND FRONTAL SYSTEMS TRACK ACROSS THE GREAT LAKES. HIGH PRESSURE
RETURNS ON SUNDAY AND WILL REMAIN FIRMLY IN PLACE ACROSS THE
NORTHERN GREAT LAKES WITH A WARM FRONT OVER THE OHIO VALLEY REGION.
THIS SET UP WILL MAKE FORECASTING PRECIPITATION CHANCES ON SUNDAY A
BIT DIFFICULT AS ANY SLIGHT SHIFT NORTH OR SOUTH WILL CAUSE EITHER A
WETTER OR DRIER FORECAST ACROSS SOUTHEAST MICHIGAN. CURRENT MODEL
RUNS ARE SHOWING SOME INDICATION THAT THERE WILL BE A BETTER CHANCE
FOR RAIN IN THE SOUTHERN CWA WITH THE NORTHERN CWA
/NORTH OF M-59/ STAYING RELATIVELY DRY. HAVE ADDED SLIGHT CHANCE
POPS TO THE NORTH AND CHANCE POPS IN THE SOUTH TO ACCOUNT FOR THIS
TREND...HOWEVER...THIS WILL HAVE TO BE FINE TUNED AS THE WEEK
PROGRESSES.

MARINE...

SMALL CRAFT ADVISORIES WILL REMAIN IN PLACE INTO THIS EVENING AS
SOUTHWEST WINDS CONTINUE TO GUST TO 25 KNOTS (OR MORE NEAR THE
SCATTERED SHOWERS AND/OR THUNDERSTORMS OVER THE AREA). OFFSHORE
WINDS WILL LIMIT THE POTENTIAL FOR WAVE GROWTH IN THE NEARSHORE
ZONES WITH SIGNIFICANT WAVE HEIGHTS EXPECTED TO MAX OUT AROUND 2 TO
LOCALLY 3 FEET. MAXIMUM WAVE HEIGHTS WILL REACH 4 TO POSSIBLY 5
FEET...MAINLY FURTHER AWAY FROM SHORE.

WINDS WILL SUBSIDE SOMEWHAT OVERNIGHT AND REMAIN MORE IN THE 10 TO
15 KNOT RANGE WITH GUSTS TO 20 KNOTS TUESDAY INTO WEDNESDAY. THE
CHANCE OF SHOWERS AND THUNDERSTORMS WILL INCREASE FROM TUESDAY INTO
TUESDAY NIGHT AND LINGER INTO WEDNESDAY AS A FRONTAL BOUNDARY EDGES
INTO THE AREA AS HIGH PRESSURE RIDGE SETTLES SLIGHTLY TO THE SOUTH
AND EAST OVER THE NEXT FEW DAYS.

&&

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

$$

AVIATION.....SC
UPDATE.......SC
SHORT TERM...JVC
LONG TERM....DG/RK
MARINE.......DG


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


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