Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 031941
AFDMQT

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

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 325 AM EDT MON AUG 3 2015

UPPER AIR PATTERN CONSISTS OF A 500 MB RIDGE OVER THE ROCKIES AND A
DEEP TROUGH OVER THE EASTERN HALF OF THE U.S. AND ACROSS THE GREAT
LAKES REGION THIS MORNING. UPPER FLOW CONTINUES TO BE FROM THE NW
AND WILL CONTINUE THAT WAY THIS FORECAST PERIOD. EMBEDDED IN THE NW
FLOW ALOFT IN THE TROUGH ARE A FEW SHORTWAVES WHICH WILL BE MOVING
THROUGH THE UPPER GREAT LAKES AND CAUSE A POSSIBILITY OF SOME
SHOWERS FOR THIS FORECAST PERIOD.

NAM HAS SOME WEAK 850-500 MB Q-VECTOR CONVERGENCE TODAY ALONG WITH
SOME MOISTURE AROUND AND BOTH MOVE OUT TONIGHT. WITH SOME MOISTURE
AROUND AND UPPER TROUGHING AS WELL...IT IS HARD TO RULE OUT SOME
SPRINKLES OR LIGHT SHOWERS AND KEPT THE SLIGHT CHANCE TO LOW CHANCE
POPS IN THE FORECAST THROUGH THIS FORECAST PERIOD AND KEPT THEM IN.
THE HIGHEST POPS WILL BE WITH THE HEATING OF THE DAY IN THE
AFTERNOON AND EARLY EVENING. DID NOT MAKE TOO MANY CHANGES TO THE
GOING FORECAST FOR TEMPERATURES.

.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 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 325 AM EDT MON AUG 3 2015

EXPECT WNW WINDS UP TO 20 KTS INTO MID WEEK AROUND DEEP LOW PRESSURE
NEAR HUDSON BAY. THE ARRIVAL OF A HIGH PRESSURE RIDGE LATER IN THE
WEEK WILL RESULT IN LIGHT WINDS UNDER 15 KTS. NO GALES SEEN ANYTIME
SOON.
&&

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

$$

SHORT TERM...07
LONG TERM...KLUBER
AVIATION...KC
MARINE...07


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