Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 121750
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
150 PM EDT FRI SEP 12 2014

.UPDATE...
ISSUED AT 101 PM EDT FRI SEP 12 2014

BAND OF ISOLD-SCATTERED SHOWERS...WITH EVEN SOME GRAUPEL MIXED IN AS
WELL DUE TO THERMAL TROUGHING ALOFT...IS SLIDING ACROSS WESTERN UPR
MICHIGAN ALONG SFC TROUGH. SEEMS THAT SOME LOW-LEVEL MOISTURE OFF LK
SUPERIOR IS ALSO HELPING THESE SHOWERS. RAIN CHANCES WILL CONTINUE
TO INCREASE THIS AFTN AND INTO THE EVENING DUE TO THIS FORCING AND
MORE SO DUE TO UPPER LEVEL TROUGH DEEPENING OVER WI AND UPR MICHIGAN.
SHIELD OF RAIN OVER SOUTHEAST MINNESOTA INTO SOUTHERN WISCONSIN TIED
TO UPPER TROUGH EXPECTED TO REACH IMT/MNM AREAS BY 5 PM ET AND INTO
MARQUETTE AND DELTA COUNTIES AROUND 7 PM ET. SHOULD BE A STEADY RAIN
OVER CNTRL UPR MICHIGAN THIS EVENING WHICH ALONG WITH TEMPS IN THE
40S WILL MAKE IT FEEL DAMP AND CHILLY. UPDATED THE POPS/WX TO EXPAND
CATEGORICAL POPS INTO CNTRL UPR MICHIGAN BY THIS EVENING. BASED ON
THE DEEPENING SYSTEM...LOOKS LIKE RAIN WILL PERSIST THROUGH AROUND
MIDNIGHT...BEFORE DIMINISHING OVER THE EAST HALF IN THE EARLY MORNING
HOURS OF SATURDAY.

FARTHER WEST...EXPECT SKIES TO CLEAR OUT OVER WESTERN UPR MICHIGAN
BY LATE EVENING. PWATS AGAIN ARE DOWN TO LESS THAN 50 PCT OF NORMAL
AND UPSTREAM DWPNTS IN NORTHEAST MINNESOTA ARE IN THE 20S TO AROUND
30 DEGREES. WINDS WILL BE LIGHT...SO SIMILAR TO LAST NIGHT...WILL
ONLY TAKE A FEW HOURS OF CLEARING SKIES TO ALLOW TEMPS TO PLUMMET.
WIDESPREAD FROST SEEMS LIKELY...AND WILL BE ASSESSING WHAT AREAS
NEED FROST/FREEZE HEADLINE THIS AFTN.
&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 433 AM EDT FRI SEP 12 2014

LATEST WV IMAGERY SHOWS THE SINKING BROAD 500MB W-E ORIENTED TROUGH
EXTENDING FROM WY TO LAKE SUPERIOR AND ONTARIO. THE RESULT HAS
BEEN...DESPITE THE LARGE AREA OF HIGH PRESSURE ACROSS MUCH OF THE N
CENTRAL U.S...MOISTURE STREAMING NE ACROSS THE S AND CENTRAL PLAINS
/FROM TX THROUGH IA AND S MN/. THE PRECIP FROM THIS SYSTEM...IN THE
FORM OF DZ AND -RA...HAS BEEN ABLE TO SHIFT INTO SW WI BY 08Z THIS
LOOKS TO BE A BIT FASTER THAN ANTICIPATED. WHILE UTILIZING A LOT OF
THE SMALLER SCALE MODEL GUIDANCE...THIS SLIGHTER EASTERN SCENARIO
WAS TAKEN INTO ACCOUNT...WITH SLIGHT CHANCE POPS MOVING INTO
DICKINSON AND MENOMINEE COUNTIES AROUND 18Z. IN THE MEANTIME WE ARE
DEALING WITH AN EMBEDDED SHORTWAVE CROSSING LAKE SUPERIOR THIS
MORNING WHICH HAS BEEN ABLE TO BRING A FEW SHOWERS TO W UPPER MI.
WILL NOT BE ABLE TO RULE OUT SLIGHT CHANCE POPS W AND CENTRAL THIS
MORNING...MAINLY NEAR LAKE SUPERIOR.

STILL...THE BEST CHANCE OF RAIN LOOKS TO BE ALONG AND OVER LAKE MI
THIS AFTERNOON...AHEAD OF THE ENTIRE 700-500MB TROUGH PUSHING ACROSS
THE CWA THIS AFTERNOON AND EVENING. GIVEN THE LATEST MODEL TREND TO
KEEP THE BULK OF THE PRECIP SE...A QUICKER EXIT LOOKED REASONABLE.

FEW CHANGES WERE MADE TO THE TEMP FCST FOR TONIGHT. HOWEVER...GIVEN
THE QUICKER EXIT OF SOME OF THE LOW LEVEL MOISTURE IT WOULDN/T BE
SURPRISING TO HAVE TEMPS END UP A BIT LOWER THAN FCST. 850MB TEMPS
WILL LINGER AROUND -2C CWA WIDE THROUGH THE SHORT TERM.
HOWEVER...DRIER AIR SHOULD FILTER INTO THE W THIRD OVERNIGHT...WITH
PW VALUES FALLING TO 35-45 PERCENT OF NORMAL AFTER 06Z SATURDAY.
ANOTHER FROST ADVISORY...OR POTENTIALLY FREEZE WARNING MAY BE NEEDED
FOR THE W THIRD.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 447 AM EDT FRI SEP 12 2014

SATURDAY INTO SATURDAY NIGHT...MODELS INDICATE SHORTWAVE TROUGH
MOVING EAST THROUGH THE WESTERN GREAT LAKES REGION FRI AND FRI NIGHT
WILL BE EAST OF THE CWA BY LATE SAT MORNING. BEHIND THE TROUGH
SHORTWAVE RIDGING WILL BUILD OVER THE WESTERN GREAT LAKES IN PART AS
A RESPONSE TO NEXT SHORTWAVE EMERGING FROM THE NRN PLAINS. ANY
LINGERING SHRA OVER THE ERN CWA EARLY SAT MORNING SHOULD QUICKLY
DISSIPATE AS SKIES BECOME PARTLY SUNNY IN RESPONSE TO
RDGG/SUBSIDENCE FROM THE WEST. SHOULD STILL SEE A DECENT AMOUNT OF
LINGERING DIURNAL SC OVER INLAND AREA ON SAT DESPITE HIGH PRES
OVERHEAD AS 8H TEMPS REMAIN AOB 0C THROUGH MIDDAY RESULTING IN STEEP
LOW-LVL LAPSE RATES. ANOTHER COOL NIGHT IS EXPECTED ON SATURDAY
NIGHT ESPECALLY EAST...BUT HIGH CLOUDS STREAMING IN FROM THE WEST
AHEAD ALONG WITH TIGHTENING PRES GRADIENT AND ASSOC MIXING AHEAD OF
THE NEXT UPPER WAVE FROM THE NRN PLAINS WILL LIKELY KEEP ALL AREAS
ABOVE FREEZING.

ON SUNDAY...THE NEXT SYSTEM WILL RAPIDLY APPROACH THE AREA IN A FAST
WNW FLOW ALOFT. MOST OF THE MODELS SUGGEST THAT THE BEST MOISTURE
AND UPWARD MOTION WILL STAY NORTH OF THE AREA ALONG AND NORTH OF THE
PROJECTED VORT TRACK. MODELS CONSENSUS INDICATES THAT LIGHT PCPN
WITH THE SYSTEM SHOULD REMAIN CONFINED TO THE WESTERN HALF OF THE
FORECAST AREA SUN AFTERNOON ALONG THE APPROACHING FRONTAL BOUNDARY.
THE DRY AIRMASS AHEAD OF THE SYSTEM SHOULD BE ENOUGH TO HOLD PCPN
FROM REACHING THE ERN COUNTIES ON SUNDAY. LIGHT PCPN WILL THEN
SPREAD ACROSS THE REST OF THE CWA SUN NIGHT WITH THE PASSAGE OF THE
FRONTAL BOUNDARY.

FOR THE EXTENDED...EXPECT AN UPPER LEVEL TROUGH TO PERSIST OVER
HUDSON BAY TROUGH THROUGH MUCH OF NEXT WEEK KEEPING A NW FLOW ACROSS
THE AREA THROUGH THE PERIOD. THIS WILL KEEP TEMPS GENERALLY BELOW
NORMAL ACROSS THE AREA. OTHERWISE...THE WEATHER SHOULD STAY FAIRLY
QUIET. NOT AS MUCH OF A CHANCE FOR LINGERING LAKE EFFECT RAIN
SHOWERS ON MONDAY AS LAKE SUPERIOR TEMPS HAVE GENERALLY COOLED OFF
INTO THE MID 40S AND MODELS HAVE COLDEST 8H TEMPS AT 0-1C...EQUATING
TO A LAKE DELTA-T OF ONLY 8-9C. MODELS HAVING A HARD TIME RESOLVING
NW FLOW SHORTWAVE AND ASSOC WEAK COLD FRONT MOVING ACROSS THE AREA
MID TO LATE WEEK. ECMWF LOOKS TO BE MOST CONSISTENT SO WILL TEND TO
FAVOR ITS TIMING OF FRONTAL BOUNDARY LATE WED INTO WED NIGHT. SINCE
MODELS SUGGEST BEST MOISTURE/LIFT WILL STAY NE OF REGION...WL ONLY
INCLUDE SLIGHT CHC POPS MAINLY FOR WED NIGHT FOR POST FRONTAL SHRA.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 149 PM EDT FRI SEP 12 2014

THE ABUNDANT MOISTURE AND AN APPROACHING LOW PRESSURE TROUGH WILL
RESULT IN BKN VFR CLOUDS THICKENING TO A LOWER MVFR CLOUD DECK BY
THIS EVENING. WIDESPREAD LGT RAIN...WITH MINIMAL VSBY RESTRICTION IS
EXPECTED AT KSAW THIS EVENING. CLOUDS GRADUALLY CLEAR OUT AT KIWD
LATE TONIGHT...BUT A BKN VFR CLOUD DECK SHOULD REMAIN AT KCMX AND
KSAW TIL END OF THE TAF PERIOD.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 433 AM EDT FRI SEP 12 2014

HIGH PRESSURE WILL REMAIN ACROSS LAKE SUPERIOR OVER MUCH OF THE
PERIOD...WITH RELATIVELY WEAK PRESSURE GRADIENTS AND GUSTS GENERALLY
BELOW 25KTS. A RIDGE WILL REMAIN ACROSS LAKE SUPERIOR THROUGH
SATURDAY NIGHT...EXTENDING FROM HIGH PRESSURE OVER THE N AND CENTRAL
PLAINS THAT WILL SLIDE TO THE MID MISSISSIPPI VALLEY SATURDAY
MORNING...AND THE OHIO VALLEY SATURDAY NIGHT. EXPECT A SMALLER LOW
OVER S MANITOBA SATURDAY AFTERNOON TO CROSS ONTARIO WHILE DRAGGING A
TROUGH ACROSS LAKE SUPERIOR SUNDAY NIGHT INTO MONDAY MORNING.
ANOTHER LARGE HIGH PRESSURE OVER THE N AND CENTRAL PLAINS ON MONDAY
WILL SLOWLY SLIDE E TO THE OHIO VALLEY AND LOWER GREAT LAKES BY
TUESDAY NIGHT. THIS WILL RESULT IN A RIDGE ACROSS LAKE SUPERIOR
MONDAY AFTERNOON THROUGH TUESDAY.
&&

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

$$

UPDATE...JLA
SHORT TERM...KF
LONG TERM...VOSS
AVIATION...JLA
MARINE...KF






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