Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 271953
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
353 PM EDT MON JUL 27 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 441 AM EDT MON JUL 27 2015

TODAY...500MB RIDGE HEIGHTS EXPECTED TO BUILD ACROSS THE REGION
TODAY WITH THE SFC RIDGE REMAINING IN PLACE. WEAK PRES GRADIENT
SHOULD RESULT IN LAKE BREEZES AGAIN OFF BOTH LAKE SUPERIOR AND
MICHIGAN BY AFTERNOON. WITH FCST 8H TEMPS OF 18-19C SHOULD AGAIN SEE
INLAND HIGH TEMPS CLIMB INTO THE UPPER 80S AND LOWER 90S WITH COOLER
TEMPS (IN THE LOWER 80S) ALONG THE GREAT LAKES SHORES. LIKE
YESTERDAY...BIG QUESTION WITH FCST IS WHETHER CONVERGENT LAKE BREEZE
BOUNDARIES WILL PROVIDE FOCUS FOR ISOLD CONVECTION AGAIN OVER THE
EAST HALF OF THE CWA. A FEW OF THE MODELS LIKE THE REGIONAL GEM AND
THE NCEP WRF MODELS SHOW ISOLD SHRA DEVELOPING OVER THE ERN THIRD OF
THE CWA THIS AFTERNOON IN AN ENVIRONMENT OF 500-1000 J/KG OF MLCAPE.
HOWEVER...MODELS ALSO INDICATE INCREASING MLCIN AS INSTABILITY
BUILDS THIS AFTERNOON WHICH MAKES SENSE GIVEN BUILDING RIDGE HEIGHTS
AND INCREASING SUBSIDENCE THROUGH THE DAY. 00Z NCAR WRF ENSEMBLE
NEIGHBORHOOD PROBABILITY DATA INDICATES A MUCH LOWER PROBABILITY OF
MEASURABLE RAIN TODAY OVER THE EAST HALF THAN WHAT IT WAS SHOWING AT
THIS SAME TIME FOR YESTERDAY. I GUESS I COULDN/T COMPLETELY RULE OUT
CONVECTION FORMING OVER THE FAR EAST...BUT FOR NOW THERE IS ENOUGH
REASON TO KEEP DRY FCST GOING.

TONIGHT...RIDGING AT ALL LEVELS CONTINUES TO DOMINATE THE REGION AND
SHOULD KEEP THE FCST AREA DRY. EXPECT LOWS TONIGHT MAINLY IN THE 60S
WITH WARMEST READINGS ALONG THE LAKE SUPERIOR SHORE IN DEVELOPING
DOWNSLOPE LIGHT SOUTHERLY FLOW.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 352 PM EDT MON JUL 27 2015

BY 00Z WEDNESDAY SHOWERS AND THUNDERSTORMS WILL BE OVER W LAKE
SUPERIOR AND FAR W UPPER MI...EXTENDING THROUGH THROUGH W AND
CENTRAL WI. THIS WILL BE THE RESULT OF THE STRONG LOW SHIFTING NE
ACROSS S CENTRAL CANADA...SITUATED OVER S MANITOBA AT 00Z WEDNESDAY.
THE WRAPPED UP LOW WILL LIKELY FEATURE AN OCCLUDED FRONT STRETCHING
THROUGH FAR W ONTARIO...BEFORE SWITCHING BACK TO A WARM FRONT OVER W
UPPER MI AND A COLD FRONT OVER ORIENTED S THROUGH FAR W LAKE
SUPERIOR. SHOWERS AND THUNDERSTORMS WILL BE LIKELY AHEAD OF THE COLD
FRONT. EXPECT THE COLD FRONT TO PUSH OVER W UPPER MI BY
06Z...STRETCH FROM AROUND MARQUETTE AND ALGER COUNTIES DOWN THROUGH
DELTA COUNTY BY 12Z...AND E OF UPPER MI BY 18Z WEDNESDAY. STILL
LOOKS LIKE A THIN LINE OF CONVECTION...TO START OUT THE EVENING.
FCST MODELS CONTINUE TO FOLLOW THE IDEA OF THE S STORMS RETAINING
THEIR CONVECTIVE LOOK AND E PROGRESSION...WHILE UPPER MI MAY HAVE A
FEW MORE BREAKS. LIKE HOW THE SPC CONVECTIVE OUTLOOKS HAVE FOLLOWED
THIS TREND. HEAVY RAIN STILL LOOKS TO BE THE MAIN THREAT AS PW
VALUES INCREASE TO NEAR 2IN OVER THE W HALF PRIOR TO 09Z
WEDNESDAY...AND OVER THE E HALF OF UPPER MI 09-15Z WEDNESDAY.

OTHERWISE WEDNESDAY WILL BE 5-10F COOLER THAN MONDAY AND TUESDAY AS
MUCH DRIER AIR WORK IN BEHIND THE COLD FRONT. PW VALUES QUICKLY FALL
TO 0.75IN OVER THE W HALF BY 15Z WEDNESDAY...BEFORE MODERATING TO
AROUND 1IN IN THE AFTERNOON AS THE 500MB LOW OVER THE W HALF OF
ONTARIO SHIFTS A TROUGH OVER THE AREA. THE ADDITION OF A FEW
AFTERNOON HOURS W WILL NOT BE OUT OF THE QUESTION...AS WELL AS
INCREASED WINDS. A W-WNW 30-50KT 850MB JET WILL QUICKLY SWING
THROUGH MID AFTERNOON INTO THE EVENING. WENT TOWARDS THE LOWER END
OF GUIDANCE TO DEW POINTS...WITH HUMIDITY VALUES BOTTOMING OUT NEAR
40 PERCENT CENTRAL IN THE AFTERNOON. THE TEMPERATURE RELIEF...BACK
TO SEASONAL NORMAL VALUES...WILL CONTINUE THROUGH AT LEAST THE REST
OF THE WORK WEEK.

DRY AIR SHOULD REMAIN IN CONTROL OF MUCH OF THE AREA THROUGH FRIDAY
AS THE 500MB LOW PUSHES ACROSS HUDSON BAY. IF WE DO GET ANY PRECIP
IT WOULD LIKELY BE OVER LAKE SUPERIOR...AS SEVERAL WAVE ROTATE
AROUND THE LOW IN W-NW FLOW. HIGHS WILL REMAIN IN THE 70S TO MID
80S...WARMEST S CENTRAL.

A STRONGER WAVE ROTATING THROUGH THE STEADY SFC-500MB LOW OVER
HUDSON BAY SHOULD SWEEP A COLD FRONT ACROSS UPPER MI SATURDAY NIGHT.
AT THIS DISTANCE THERE ARE A FEW DISCREPANCIES ON STRENGTH AND
TIMING...BUT ENOUGH CONFIDENCE FOR HIGH CHANCE POPS SATURDAY NIGHT.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 141 PM EDT MON JUL 27 2015

HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH TONIGHT WITH VFR
CONDITIONS EXPECTED. ALTHOUGH SOME SHOWERS OR REMNANTS OF OVERNIGHT
CONVECTION OVER MN MAY MOVE INTO WESTERN UPPER MICHIGAN TUE MORNING.
HOWEVER...WITH ONLY A LOW PROBABILITY OF MAINLY JUST WEAKENING
SHOWERS...NO PCPN WAS INCLUDED IN THE FCST AS VFR CONDITIONS PERSIST.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 441 AM EDT MON JUL 27 2015

HIGH PRESSURE OVER LOWER MI WILL KEEP A RIDGE ACROSS LAKE SUPERIOR
THROUGH EARLY TUESDAY. THIS WILL KEEP WINDS GENERALLY LESS THAN
20KTS AND LINGERING LOW-LEVEL MOISTURE COULD LEAD TO PATCHY FOG
FORMING. DEEPENING LOW PRESSURE OVER S SASKATCHEWAN TUESDAY MORNING
WILL RACE ACROSS MANITOBA TUESDAY NIGHT...AND ACROSS ONTARIO TO
HUDSON BAY WEDNESDAY NIGHT. LOOK FOR THIS LOW TO REMAIN ACROSS
HUDSON BAY THROUGH AT LEAST FRIDAY. THE RESULT WILL BE A TROUGH
EXTENDING DOWN THROUGH LAKE SUPERIOR TUESDAY NIGHT AND
WEDNESDAY...ALONG WITH THE RETURN OF STRONGER WINDS. S-SW WINDS
AHEAD OF THE TROUGH COULD GUST NEAR 25KTS OVER MAINLY E LAKE
SUPERIOR TUE NIGHT...WITH SW-W WINDS APPROACHING 35 KNOT GALES ON
WEDNESDAY IN THE WAKE OF THE TROUGH...ESPECIALLY OVER THE WEST HALF.
WEST WINDS TO 30 KNOTS COULD LINGER INTO WEDNESDAY EVENING EAST
HALF.

THE TROUGH WILL SHIFT TO THE NEW ENGLAND STATES
THURSDAY...ALLOWING A WEAK RIDGE TO BUILD INTO THE UPPER GREAT LAKES
THURSDAY. IT WILL QUICKLY BE REPLACED BY A WEAK TROUGH THURSDAY
NIGHT INTO FRIDAY...ROTATING AROUND THE HUDSON BAY LOW.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&

$$

SHORT TERM...VOSS
LONG TERM...KF
AVIATION...JLB
MARINE...VOSS



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