Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 031947
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
347 PM EDT MON AUG 3 2015

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 346 PM EDT MON AUG 3 2015

12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CYC NW FLOW ARND
CLOSED LO OVER FAR NRN ONTARIO DOMINATING THE UPR LKS. UPSTREAM 12Z
RAOBS AT INL/YPL SHOW SOME FAIRLY DEEP MSTR...WITH H85-7 DEWPT
DEPRESSIONS NO MORE THAN A FEW DEGREES C. WITH LARGER SCALE CYC FLOW
AND H85 CAA /12Z H85 TEMPS WERE 11C AT GRB/APX BUT ONLY 3C AT
YPL/...BKN LO CLDS ARE PRESENT OVER THE CWA. THERE HAVE BEEN A FEW
SHOWERS MAINLY OVER THE INTERIOR AS WELL WITH SOME DIURNAL HEATING
AND IN ASSOCIATION WITH SHRTWV NOTED ON WV IMAGERY PASSING OVER NE
LK SUP/ACCOMPANYING DPVA AND DEEP LYR QVECTOR CNVGC...BUT INTENSITY/
COVERAGE OF THESE HAS BEEN LIMITED BY SOME CAPPING AOA H7 AS SHOWN
ON THE 12Z YPL RAOB AND RUC ANALYSIS SNDGS FOR SITES IN THE CWA. THE
CAA AND CLD COVER HAVE KEPT TEMPS BLO NORMAL.

MAIN FCST CONCERNS IN THE SHORT TERM FOCUS ON CLD TRENDS AND POPS.

TNGT...EXPECT ANY ONGOING SHOWERS EARLY TO TEND TO DIMINISH IN
THE EVNG WITH NOCTURNAL COOLING/ARRIVAL OF DNVA/LARGER SCALE
SUBSIDENCE IN THE WAKE OF PASSING SHRTWV TO THE NE. SOME OF THE
MODELS INDICATE ANOTHER SHRTWV NOW SLIDING SEWD THRU MANITOBA WL
ARRIVE DURING THE NGT AND RESULT IN MORE ISOLD SHOWERS. LINGERING
CYC FLOW AND CONTINUED MOIST...CYC NW H85 FLOW WL MAINTAIN A GOOD
DEAL OF CLD COVER THAT WL LIMIT THE DIURNAL TEMP FALL. BUT TEMPS
SHOULD STILL FALL INTO THE UPR 40S AT MANY INTERIOR LOCATIONS AS H85
TEMPS DIP TO ARND 6C.

TUE...ALTHOUGH MOIST CYC H85 FLOW WL PERSIST...MODELS SHOW ARRIVAL
OF DNVA/FAIRLY SHARP DEEP LYR QVECTOR DVGC/SUBSIDENCE IN THE WAKE OF
PASSING SHRTWV DOMINATING...WITH SFC HI PRES BLDG INTO THE AREA
DURING THE AFTN. SO ANY MRNG SHOWERS SHOULD DIMINISH WITH TIME
DESPITE THE DIURNAL HEATING THAT WOULD NORMALLY ENHANCE PCPN CHCS.
EXPECT ANOTHER RELATIVELY COOL DAY WITH LINGERING LO CLDS AND H85
TEMPS IN THE 6-8C RANGE THAT WL SUPPORT MAX TEMPS INTO THE LO 70S
OVER THE SCENTRAL...WITH MAINLY 60S CLOSER TO LK SUP.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 341 PM EDT MON AUG 3 2015

BELOW AVERAGE TEMPERATUES AND A FEW SMALL CHANCES OF RAIN WILL BE
THE RULE ACROSS UPPER MI INTO THIS WEEKEND.

TUESDAY NIGHT...A MID-LEVEL LOW CENTERED OVER JAMES BAY WILL BEGIN A
SLOW PUSH EASTWARD TUESDAY NIGHT. ANY SHOWER ACTIVITY THAT OCCURS
DURING THE DAY TUESDAY AS AN ASSOCIATED TROUGH AXIS CROSSES UPPER MI
SHOULD END BY TUESDAY EVENING UNDER INCREASED DRYING AND DEEP
SUBSIDENCE. THE SFC GRADIENT WINDS WILL BECOME LIGHT/CALM AS A SFC
RIDGE BUILDS FROM SOUTH CENTRAL CANADA TO THE WESTERN CWA. WHILE
PWAT VALUES OF AROUND 0.75 INCHES WILL BE FAR FROM IDEAL FOR
SUBSTANTIAL COOLING...INLAND LOCATIONS SHOULD DROP WELL INTO THE 40S
GIVEN THE OVERALL COOL AIR MASS IN PLACE. UPPER 30S FOR THE TYPICAL
COLDEST SPOTS WILL NOT BE OUT OF THE QUESTION FOR THE INTERIOR WEST.
HAVE STEERED CLEAR OF THE COLDEST GUIDANCE FOR NOW AS ANOTHER WEAK
MID-LEVEL TROUGH CROSSING THE AREA OVERNIGHT MAY BE ENOUGH TO
PRODUCE SOME SCATTERED CLOUDS.

BY WEDNESDAY...THE MORNING LOOKS TO BE MOSTLY SUNNY...BUT YET
ANOTHER SUBLTE TROUGH LOOKS TO REACH THE WESTERN CWA LATE IN THE
AFTERNOON. A SHALLOW LAYER OF MOISTURE BETWEEN 800 AND 850 HPA
COMBINED WITH WEAK FORCING FROM THE TROUGH MAY BE ENOUGH TO PRODUCE
LIGHT SHOWERS. IF THIS OCCURS...THE FOCUS WILL BE ON A WEAK LAKE
SUPERIOR LAKE BREEZE...AND A LAKE MI/GREEN BAY LAKE BREEZE THAT
SHOULD PUSH WELL INLAND ON LIGHT EASTERLY WINDS. HAVE OPTED TO ADD A
SLIGHT CHANCE OF AFTERNOON SHOWERS FOR THE CENTRAL CWA AWAY FROM THE
GREAT LAKES AT THIS TIME.

THURSDAY...A SHORTWAVE TROUGH ERODING A RIDGE OVER THE NORTHERN
PLAINS TUESDAY NIGHT IN CONJUNCTION WITH THE RIGHT ENTRANCE OF AN
UPPER JET WILL INDUCE MULTIPLE AREAS OF CONVECTION ACROSS THE
NORTHERN PLAINS INTO THE MID/UPPER MS VALLEY WED. LATEST GUIDANCE IS
SPLIT ON THE INTENSITY OF THE NORTHERN SECTION OF THE
CONVECTION...WITH THE ECMWF BEING MOST AGRESSIVE. IT APPEARS ANY
NORTHERN CONVECTION WILL STRUGGLE TO TRACK WELL EAST ACROSS THE CWA
AS IT ENCOUNTERS AN INCREASINGLY DRIER AIR MASS ACROSS NORTHERN WI
AND WESTERN LAKE SUPERIOR. WIDELY ISOLATED SHOWERS/SPRINKLES COULD
OCCUR AS THE TROUGH AXIS PASSES THURSDAY MORNING...BUT CONFIDENCE IS
MUCH TOO LOW TO INTRODUCE ANY MENTION AT THIS TIME.

FRIDAY THROUGH MONDAY...THE EVOLUTION OF THE SYNOPTIC PATTERN
BECOMES MORE COMPLICATED BEGINNING LATE THIS WEEK. SIMPLY PUT...THE
LONG TERM MODELS ARE IN LITTLE AGREEMENT. IN FACT...THE 12Z RUN OF
THE GFS SHOWS A STACKED SHORTWAVE RIDGE OVER THE CWA AT 12Z
SAT...WHILE THE ECMWF HAS A MID-LEVEL TROUGH LAGGING BEGIND A SFC
TROUGH JUST EAST OF UPPER MI. MEANWHILE...THE CANADIAN GEM CANNOT
CHOSE WHICH OF THE OTHER TWO TO FOLLOW...WITH IT MORE IN LINE WITH
THE ECMWF THU INTO FRI...AND THE GFS SAT INTO SUN. MOST OF THIS IS A
RESULT OF THE ECWMF LEAVING BEHIND THE SW EXTENT OF THURSDAYS TROUGH
IN RESPONSE TO CONVECTIVE FEEDBACK ACROSS THE NORTHERN PLAINS. WILL
STILL HEDGE TOWARD A DRIER SOLUTION FOR MOST DAYS UNTIL THINGS WORK
THEMSELVES OUT IN THE GUIDANCE.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 148 PM EDT MON AUG 3 2015

EXPECT QUITE A BIT OF LO CLDS TO LINGER THIS FCST PERIOD AS THE
UPPER GRT LKS WL BE DOMINATED BY A MOIST CYC NW FLOW ARND LO PRES
NEAR HUDSON BAY. ALTHOUGH THERE COULD BE A FEW -SHRA THIS AFTN...VFR
CONDITIONS WL PREDOMINATE WITH A RELATIVELY DRY NEAR SFC LYR. CIGS
MAY DROP INTO THE HI END MVFR RANGE LATE TNGT IN THE PRESENCE OF
DIURNAL COOLING AND FOLLOWING THE PASSAGE OF A DISTURBANCE THAT
COULD BRING A FEW MORE -SHRA OVERNGT. EVEN IF CIGS DROP INTO THE
MVFR CATEGORY LATE...DAYTIME HEATING AND LLVL DRYING WL ALLOW A
RETURN OF VFR CONDITIONS AT ALL THE SITES BY MID/LATE MRNG ON TUE.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 346 PM EDT MON AUG 3 2015

EXPECT WNW WINDS UP TO 20 KTS INTO MID WEEK AROUND DEEP LOW PRESSURE
NEAR HUDSON BAY. A WEAK PRES GRADIENT WILL DOMINATE DURING THE LATE
WEEK...RESULTING IN WINDS UNDER 20 KTS. NO GALES SEEN ANYTIME SOON.
&&

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

$$

SHORT TERM...KC
LONG TERM...KLUBER
AVIATION...KC
MARINE...KC


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