Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 200748
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
348 AM EDT SAT SEP 20 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 359 PM EDT FRI SEP 19 2014

MAIN CONCERNS DURING THIS TIME PERIOD IS THE GUSTY WIND THIS
AFTERNOON ALONG WITH SHOWER AND THUNDERSTORM POTENTIAL TONIGHT AND
SATURDAY.

THIS AFTERNOON...THE MAIN ISSUE THIS AFTERNOON IS THE CONTINUED
STRONG WIND GUSTS ACROSS THE REGION. THIS IS DUE TO A VERY TIGHT
PRESSURE GRADIENT BETWEEN STRONG HIGH PRESSURE DEPARTING OVER THE
NORTHEAST AND STRENGTHENING LOW PRESSURE PUSHING FROM MANITOBA INTO
ONTARIO. MODELED 850MB WINDS ARE PROGGED TO BE AROUND 40 TO 45 KNOTS
ACROSS THE AREA. THIS IS ALSO SUPPORTED BY THE MQT VAD WIND PROFILES.
WHILE WE MAY NOT ACTUALLY ABLE TO MIX UP TO 850MB...IT DOES LOOK LIKE
WE COULD MIX TO NEAR 900MB WHICH WOULD EASILY GIVE WIND GUSTS AROUND
30 TO 35 MPH WITH A FEW GUSTS CLOSE TO 40 MPH...ESPECIALLY OVER THE
CENTRAL AND EASTERN U.P. AS THE GRADIENT SHIFTS EASTWARD BY LATE
AFTERNOON EXPECT WINDS TO DIMINISH OVER THE WESTERN HALF OF THE UPPER
PENINSULA...HOWEVER...THE EAST MAY SEE STRONGER GUSTS THROUGH THE
EARLY EVENING HOURS. AS FAR AS PRECIPITATION GOES...MODELS CONTINUE
TO SLOW THE PRECIPITATION MOVEMENT INTO THE UPPER PENINSULA. A WARM
FRONT WILL CONTINUE TO LIFT NORTH OF THE U.P. LATE THIS
AFTERNOON...ALLOWING SHOWERS AND A FEW THUNDERSTORMS TO DEVELOP. THIS
WILL REMAIN MAINLY OVER THE FAR WESTERN U.P. WHERE THE BETTER
ISENTROPIC ASCENT AND INCREASED MOISTURE REMAINS. ADDITIONALLY...THE
BETTER SYSTEM FORCING WILL REMAIN NORTH AND WEST OF THE U.P. AS SHOWN
BY ANALYZING DEEP LAYER QDIV ALONG WITH DEEP LAYER RH.


TONIGHT THROUGH SATURDAY...A COLD FRONT WILL APPROACH THE UPPER
GREAT LAKES REGION TONIGHT AS THE SURFACE LOW CONTINUES ACROSS
ONTARIO. THE BETTER FORCING THROUGH TONIGHT WILL REMAIN OVER MAINLY
THE NORTH HALF OF THE UPPER PENINSULA...CLOSER TO THE LOW PRESSURE
CENTER.  HAVE GENERALLY PLACED THE BEST POPS OVER LAKE
SUPERIOR...HOWEVER...AN INCREASED CHANCE OF SHOWERS AND A FEW
THUNDERSTORMS WILL BE POSSIBLE AS THE COLD FRONT PUSHES THROUGH THE
REGION AS SHOWN BY ANALYZING 850MB THETA E ALONG WITH SURFACE WINDS.
THE INCREASED INSTABILITY TONIGHT WILL COME FROM COOLER AIR ALOFT
ASSOCIATED WITH AN UPPER LEVEL 500MB SHORTWAVE PROGGED TO PUSH
ACROSS THE REGION OVERNIGHT. PLENTY OF MOISTURE WILL REMAIN IN PLACE
FOR SHOWERS AND THUNDERSTORMS AS SOUNDING REMAIN FAIRLY MOIST AND
1000-500MB RH VALUES REMAIN FAIRLY HIGH. THE COLD FRONT WILL BE OVER
THE EASTERN UPPER PENINSULA BY 18Z SATURDAY...PUSHING MOST OF THE
SHOWER AND THUNDERSTORM POTENTIAL OVER THE FAR EASTERN U.P. A FEW
THUNDERSTORMS COULD BE STRONG SATURDAY AFTERNOON AHEAD OF THE COLD
FRONT OVER THE FAR EASTERN U.P. SATURDAY AFTERNOON AS THE SHORTWAVE
AND COLD FRONT BECOME NEARLY COLLOCATED WHILE SHEAR VALUES AROUND
AROUND 35 TO 40 KNOTS PERPENDICULAR TO THE FRONT. STRONG WIND GUSTS
AND SMALL HAIL WOULD BE THE MAIN THREAT. BY LATE IN THE DAY
SATURDAY...ADDITIONAL SHOWERS AND AN ISOLATED THUNDERSTORM OR TWO
WILL BEGIN PUSHING IN OVER THE FAR WEST AS THE NEXT 500MB SHORTWAVE
ROTATES INTO THE THE AREA.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 343 AM EDT SAT SEP 20 2014

ON SUNDAY...THE PV ANOMALY CURRENTLY OVER CENTRAL ALBERTA WILL BE
JUST SOUTH OF THE AREA. THIS WILL ALLOW FOR LOW PRESSURE TO DEVELOP
SATURDAY NIGHT INTO SUNDAY ALONG THE FRONT WHICH IS EXPECTED TO MOVE
THROUGH THE AREA THIS AFTERNOON AND THIS EVENING. EXPECT ANY RAIN
ASSOCIATED WITH THIS WAVE TO BE FOCUSED NR THE MI/WI BORDER SUNDAY
MORNING WHERE THE BEST MOISTURE AND FRONTOGENETIC FORCING WILL BE
LOCATED. HOWEVER...THIS SHOULD MOVE OUT BY AFTERNOON WITH HIGH
PRESSURE AND ANTICYCLONIC FLOW MOVING IN DURING THE DAY. AS
SUCH...WILL CONTINUE WITH CHANCE POPS ACROSS THE EAST HALF OF THE
FORECAST AREA SUN MORNING. WITH STRONG COLD ADVECTION AND A
TIGHTENING PRES GRADIENT...IT WILL BE QUITE RAW SUN MORNING WITH
GUSTY NORTH WINDS AND TEMPS ONLY IN THE 40S. TEMPS SHOULD REBOUND
SOME SUN AFTN AS THE SUN COMES OUT...BUT THE WORRY IS THAT AREAS
CLOSER TO LAKE SUPERIOR MAY STAY IN THE CLOUDS FOR MUCH OF THE DAY
DUE TO THE UPSLOPE NORTHERLY FLOW AND CONTINUED LOW LEVEL MOISTURE
PER MODEL SOUNDINGS. WILL THEREFORE TREND TOWARD THE LOWER END OF
GUIDANCE FOR SUNDAY WITH TEMPS NEAR LAKE SUPERIOR IN THE LOW-MID 50S
WHILE AREAS CLOSER TO THE WI BORDER WILL BE CLOSE TO 60.

SUN NIGHT INTO MONDAY WILL BE QUITE TRANQUIL WITH HIGH PRES IN
CONTROL. WOULD NOT BE SHOCKED TO SEE SOME FROST SUN NIGHT/MON
MORNING WITH CLEARING SKIES AND LIGHT WINDS DUE TO PWAT VALUES UNDER
0.40 INCH. IN FACT...EVEN THE NATIVE NAM GUIDANCE SUGGESTS TEMPS
NEAR FREEZING AT MQT. WILL THEREFORE EXPAND PATCHY FROST FOR MOST
INLAND LOCATIONS IN THE UPPER PENINSULA. THE EAST MAY SEE THE
COLDEST TEMPS MON MORNING DUE TO THE COLDEST TEMPS ALOFT.
OTHERWISE...MONDAY WILL BE A PLEASANT AUTUMN DAY WITH MOSTLY SUNNY
SKIES AND TEMPS IN THE 60S AS 850MB TEMPS RISE TO +10 BY MON
EVENING.

TUESDAY THROUGH FRIDAY...LOOKS LIKE A QUIET AND INDIAN SUMMER TYPE
SETUP FOR THE WEEK WITH BUILDING HEIGHTS ACROSS THE REGION MIDWEST
AND GREAT LAKES...LEADING TO GENERALLY DRY AND WARM CONDITIONS. ONLY
CHANCE FOR RAIN WOULD BE WED NIGHT INTO THU WITH THE GFS AND ECMWF
SUGGESTING A WEAK UPPER DISTURBANCE MOVING THROUGH THE AREA IN THE
W-NW FLOW ALOFT. OTHERWISE...EXPECT TEMPS WELL INTO THE 70S FOR MUCH
OF THE TIME PERIOD. WARMEST DAY MAY BE FRIDAY WITH THE GFS AND ECMWF
SUGGESTING 850MB TEMPS OF +14 AHEAD OF A DEVELOPING TROUGH OVER THE
HIGH PLAINS.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 119 AM EDT SAT SEP 20 2014

EXPECT CIGS TO GRADUALLY DETERIORATE TO MVFR AND THEN IFR AT ALL 3
TAF SITES BY SUNRISE AS SW FLOW ADVECTS MORE LLVL MSTR INTO UPR MI
IN ADVANCE OF AN APRCHG COLD FNT. BEST CHC FOR SOME LIFR CONDITIONS
WL BE AT CMX...WHERE WSHFT TO A MORE FVRBL UPSLOPE W DIRECTION
COINCIDENT WITH THE ARRIVAL OF THE FNT WL ENHANCE UPSLOPE COOLING.
THERE WL BE SOME -SHRA...AND EVEN AN ELEVATED TS IS PSBL...BUT NO
SGNFT VSBY RESTRICTIONS ARE LIKELY. AS DRY AIR MOVES INTO THE AREA
ON SAT BEHIND THE FROPA...CONDITIONS WL IMPROVE TO VFR. BUT ANOTHER
TROF WL SWING THRU THE AREA THIS EVNG...AND SOME LO CLDS/MVFR OR
EVEN IFR CIGS MAY MOVE IN OFF LK SUP.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 359 PM EDT FRI SEP 19 2014

AS A STRONG PRESSURE GRADIENT LINGER OVER THE EASTERN HALF OF LAKE
SUPERIOR...EXPECT STRONG SOUTHERLY WINDS TO GUST TO 20 TO 30 KNOTS
THROUGH THE EVENING HOURS. A FEW GALES TO 35 KNOTS WILL BE POSSIBLE
FOR THE HIGHER PLATFORMS AND CLOSER TO THE UPPER MI SHORELINE
THROUGH THIS EVENING. THESE GUSTY SOUTH WINDS WILL GRADUALLY
DIMINISH ACROSS THE EAST HALF OF THE LAKE OVERNIGHT TONIGHT THROUGH
SATURDAY AS THE TROUGH MOVES ACROSS LAKE SUPERIOR. EXPECT A PERIOD
OF WESTERLY WINDS OF UP TO 20 KNOTS SATURDAY AFTERNOON AND NW WINDS
TO 20 KNOTS SUNDAY BEHIND THIS TROUGH. WINDS WILL REMAIN UNDER 20
KNOTS THROUGH MUCH OF NEXT WEEK AS A SERIES OF HIGH PRESSURE SYSTEMS
MOVES OVER THE UPPER GREAT LAKES. IT IS POSSIBLE...HOWEVER...THAT
WIND COULD GUST TO 25 KNOTS MONDAY AFTERNOON AS A FAST MOVING TROUGH
SWINGS ACROSS LAKE SUPERIOR.
&&

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

$$

SHORT TERM...KEC
LONG TERM...MRD
AVIATION...KC
MARINE...KEC






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