Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 300850
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
450 AM EDT SAT AUG 30 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 448 AM EDT SAT AUG 30 2014

MANY AREAS OF SHOWERS AND ISOLD TSRA IMPACTING UPR GREAT LAKES THIS
MORNING. WV LOOP POINTS TO PRIMARY SHORTWAVE FM CENTRAL IOWA INTO
WESTERN WI WITH ASSOCIATED SFC LOW OVER WESTERN WISCONSIN...LIFTING
NORTHEAST TOWARD UPR MICHIGAN. SFC TROUGH/COOL FRONT EXTENDS FM THAT
LOW TO THE NORTH OVER WESTERN UPR MICHIGAN. SHRA/TSRA OVER EASTERN
SECTIONS OF CWA MAINLY TIED TO H85 MOISTURE TRANSPORT AND ON EDGE OF
UP TO 1000J/KG OF MUCAPE LIFTED FM 1KM. HAVE BEEN ISOLD TSRA WITHIN
LAST FEW HOURS VCNTY OF ESC/ISQ/ERY...BUT LIMITED DEPTH OF CORES
WITH THE TSRA IS LIKELY JUST RESULTING IN BRIEF HEAVY DOWNPOURS.
SHOWERS/RAIN OVER WI WITH NOT NEAR AS MUCH TSRA ARE DUE TO H85-H5
Q-VECTOR CONVERGENCE AND UVM FM THE SHORTWAVE WITH UVM ALSO AIDED
BY SFC-H85 LOWS.

EXPECT DECENT COVERAGE OF SHOWERS THROUGH MIDDAY MAINLY OVER EAST
HALF OF CWA AS THE SHORTWAVE LIFTS TO THE NORTHEAST. UPSLOPE NORTH
FLOW IN WAKE OF FRONT SETTLING OVER NORTHERN UPR MICHIGAN WILL ALSO
HELP OUT THE SHOWERS AND COULD EVEN RESULT IN SOME DZ AND FOG. TEMPS
WILL GO NOWHERE FAST...WITH MINIMAL CHANGE IN THE MAINLY 60S
READINGS OVER THE WEST AND NORTH DUE TO COOL ADVECTION AS WINDS TURN
OFF LK SUPERIOR. COULD SEE TEMPS REACH AROUND 70 DEGREES IN THE FAR
SOUTH OR SOUTHEAST CWA THIS AFTN...BUT THIS WILL DEPEND ON HOW
QUICKLY THE WIDESPREAD SHOWERS EXIT THIS AFTN. SINCE IT IS ALREADY
IN THE MIDDLE 60S THIS MORNING...WOULD NOT TAKE MUCH TO PUSH PAST 70
DEGREES. TSRA CHANCES FROM HERE ON OUT SEEM MINIMAL AS THE STRONGER
LOW-LEVEL JET AND MOISTURE TRANSPORT WILL STAY EAST AND SOUTHEAST OF
UPR MICHIGAN. KEPT CHANCES HIGHEST OVER FAR SOUTH AND EAST CWA ON
EDGE OF 0.5-1.0KM MUCAPE AND IN SIMILAR REGION TO WHERE TSRA ARE
CURRENTLY ONGOING. LIMITED INSOLATION AND WEAK LOW-LEVEL MOISTURE
ADVECTION SHOULD RESULT IN VERY LIMITED POTENTIAL OF ANY STRONGER
STORMS. HEAVY DOWNPOURS SHOULD BE THE PRIME HAZARD WITH ANY TSRA.

LAST ITEM FOR TODAY. NEAR LK SUPERIOR LATER THIS AFTN AS NORTH WINDS
INCREASE THERE COULD BE MODERATE SWIM RISK DEVELOP FM MQT TO GRAND
MARAIS. SOUNDINGS INDICATE SHALLOW DEPTH TO MIXED LAYER BUT THERE
COULD BE PERIOD OF 15-20 KT WINDS TO THE SFC WITH WAVES INCREASING
TO 4 FT.

FOR TONIGHT...SHOWERS WILL GRADUALLY DIMINISH OVER THE EAST HALF.
SOUNDINGS AND CROSS-SECTIONS FM NAM/GFS/GEM-REGIONAL POINT TO A LOT
OF LOW-LEVEL MOISTURE STAYING IN PLACE THOUGH. SFC LOW NEAR SAULT
STE MARIE THIS EVENING RESULTS IN A NNW CYCLONIC FLOW SFC-H9 MAINLY
FM MQT TO ERY. KEPT SMALL POPS GOING FOR THESE AREAS THROUGH AROUND
MIDNIGHT. COULD EVEN BE MORE OF A DRIZZLE TYPE SETUP AS DEEPER
MOISTURE THINS OUT. WITH THAT THINNING MID-LEVEL MOISTURE...COULD
ALSO SEE AREAS OF FOG LATER AT NIGHT AS BLYR COOLS AND SINCE THERE
IS PLENTY OF LOW-LEVEL MOISTURE LINGERING. HIGHEST PROBABILITY FOR
DENSE FOG WILL BE INLAND OVER THE WEST HALF.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 440 AM EDT SAT AUG 30 2014

SUNDAY LOOKS TO BE A DRY AND QUIET DAY WITH UPPER WAVE EAST OF THE
AREA. PRECIPITABLE WATER VALUES DROP TO AS LOW AS 0.75 INCH ACROSS
UPPER MICHIGAN BEHIND THE WAVE...SO IT SHOULD END UP BEING A FAIRLY
PLEASANT DAY WITH JUST DIURNAL CUMULUS TO DEAL WITH. STRONG RETURN
FLOW AND WARM ADVECTION DEVELOPS LATER IN THE AFTERNOON AHEAD OF THE
NEXT SYSTEM. THE NWP IS FAIRLY CONSISTANT IN SHOWING A LINE OF
SCATTERED CONVECTION ACROSS MN ALONG THE COLD FRONT LATE SUN AFTN
THEN MOVING EASTWARD OVERNIGHT ON SUNDAY. THE EXPECTATION IS THAT THE
AREA OF PCPN ALONG THE COLD FRONT WILL BECOME MORE WIDESPREAD
OVERNIGHT AS THE UPPER DIVERGENCE ASSOCIATED WITH THE EXIT REGION OF
THE CURVED JET CATCHES UP WITH THE FRONT SUN NIGHT INTO MONDAY
PERHAPS DEVELOPING INTO A FRONTAL MCS.

OVERALL...THE NWP ARE IN VERY GOOD AGREEMENT ON THE FRONTAL
TIMING...WITH THE FRONT SLOWING DOWN AS IT PASSES ACROSS THE AREA
DUE TO THE UPPER TROUGH BECOMING SLIGHTLY NEGATIVE. GUIDANCE SUGGESTS
THE FRONT WILL BE ACROSS CENTRAL UPPER MICHIGAN ON 18Z MONDAY THEN
EAST OF THE U.P. BY 06Z TUE. WITH THE STRONG SOUTHERLY LOW LEVEL JET
OF 40-50 KT LEADING TO STRONG MOISTURE FLUX CONVERGENCE AND HIGH WARM
CLOUD DEPTH ABOVE 11 KFT...EXPECT ANOTHER ROUND OF MODERATE RAIN ON
MONDAY. THE NAM IS THE LEAST AGRESSIVE IN THE HEAVIER PCPN...BUT THAT
MODEL HAS BEEN DISCARDED GIVEN THE OBVIOUS CUMULUS PARAMATERIZATION
ISSUES OVER NRN MN AND NW ONTARIO LEADING TO THE UPPER TROUGH
BECOMING CLOSED OFF LEADING TO THE BEST MOISTURE CONVERGENCE AND
HEAVY PCPN OVER THIS AREA. WILL THEREFORE CONTINUE CATEGORICAL OR
LIKELY POPS ACROSS THE ENTIRE AREA AS THE FRONTAL BAND MOVES EAST.

REGARDING THE SEVERE POTENTIAL ON MONDAY...THE STRONG KINEMATIC
STRUCTURE OF THE SYSTEM WITH 0-6KM SHEAR OF 50+ KT AND 0-1KM SHEAR
OF 20-30 KT WOULD IMPLY THAT THE WIND FIELDS WOULD BE SUFFICENT
ENOUGH FOR SEVERE WEATHER POTENTIAL. HOWEVER...SEEING ENOUGH
INSTABILITY TO REALIZE ANY POTENTIAL FOR SEVERE WEATHER MAY BE
DIFFICULT DUE TO CLOUD COVER FROM ANY ONGOING CONVECTION TO THE WEST
AND THE BACKED LOW LEVEL FLOW OFF OF LAKE MICHIGAN KEEPING THE
IMMEDIATE LOW LEVELS RATHER STABLE. AT THIS TIME...ONE COULD NOT
RULE OUT ANY STRONGER STORMS ACROSS THE EASTERN HALF OF THE FORECAST
AREA AS THIS REGION WILL HAVE THE BEST CHANCE TO SEE SOME PARTIAL
SUNSHINE IN THE MORNING HOURS AHEAD OF THE FRONT. HOWEVER...AT THIS
TIME SEVERE WEATHER DOES NOT SEEM LIKE A MAJOR CONCERN. IF THE FRONT
SLOWS DOWN HOWEVER...SEVERE WEATHER COULD BECOME A CONCERN GIVEN THE
QUITE FAVORABLE TROPOSPHERIC WIND FIELDS.

FOR THE REMAINDER OF THE WEEK...EXPECT GENERALLY ZONAL FLOW ACROSS
THE NORTHERN TIER TO PERSIST WITH STRONG RIDGING ACROSS THE SOUTHERN
UNITED STATES. THE GLOBAL MODELS ARE IN FAIRLY GOOD AGREEMENT IN
SHOWING A SHORT WAVE TROUGH AND ASSOCIATED COLD FRONT MOVING THROUGH
THE UPPER GREAT LAKES ON THURSDAY WITH CHANCES FOR SHOWERS AND
STORMS ACROSS THE ENTIRE AREA. SOME INDICATIONS BY THE GFS AND GEM
THAT THIS FRONT WILL LAY OUT ACROSS THE UPPER GREAT LAKES LATE NEXT
WEEK WHICH WOULD ALLOW FOR CONTINUED CHANCES FOR SHOWERS/STORMS.
HOWEVER...THE ECMWF DRIVES THIS FRONT SOUTHWARD LEADING TO A DRY END
OF THE WEEK. WITH THE ZONAL FLOW AND STRONG RIDGING TO THE
SOUTH...WOULD NOT BE SURPRISED IF THIS FRONT HANGS UP ACROSS THE
NORTHERN GREAT LAKES. AS SUCH...HAVE KEPT LOW POPS FOR FRIDAY ACROSS
THE AREA. OTHERWISE...IT LOOKS LIKE TEMPERATURES WILL BE SEASONABLE
IF NOT SLIGHTLY ABOVE NORMAL FOR THIS TIME OF YEAR ESPECIALLY ON
THURSDAY AHEAD OF THE COLD FRONT.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 143 AM EDT SAT AUG 30 2014

ALTHOUGH CONDITIONS HAVE TEMPORARILY IMPROVED TO VFR...PASSAGE OF
APRCHG COOL FNT AND WSHFT TO AN UPSLOPE N DIRECTION OFF LK SUP IN
PRESENCE OF MOIST...SHALLOW COOL AIRMASS WL RESULT IN A RETURN TO
IFR WX. BEST CHANCE OF OCCASIONAL SHOWERS THROUGH THIS MORNING WILL
BE AT KSAW AS WAVE OF RAIN OVER WI SLIDES TO THE NORTHEAST OVER
MAINLY THE EAST TWO-THIRDS OF UPR MICHIGAN. DAYTIME HEATING WL ALLOW
FOR SOME IMPROVEMENT TO MVFR DURING THE AFTN AND EVEN TO VFR LATE IN
THE DAY OVER THE WESTERN SITES CLOSER TO INCOMING DRY AIR AND WHERE
VEERING FLOW TOWARD THE NE WL NOT PRESENT AS MUCH OF AN UPSLOPE
COMPONENT. SINCE THIS FLOW IS MORE FVRBL FOR SAW...OPTED TO FCST
LINGERING LO CLDS/NO IMPROVEMENT ABOVE MVFR THERE. WITH THE ONSET OF
NOCTURNAL COOLING...EXPECT FOG TO DVLP LATE SATURDAY EVNG WHERE
THERE IS MORE LIKELY TO BE SOME CLRG AT CMX AND IWD. CONDITIONS
SHOULD RETURN TO IFR AT SAW AS WELL.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 448 AM EDT SAT AUG 30 2014

LOW PRESSURE CROSSING THE REGION TODAY WILL RESULT IN A WIND SHIFT
WITH MOST OF LK SUPERIOR SEEING NORTH-NORTHEAST WINDS BY EARLY AFTN.
WINDS WILL BE LESS THAN 20 KTS THOUGH. HIGH PRESSURE LIGHTENS WINDS
TONIGHT THROUGH SUNDAY. A STRONG LOW PRESSURE SYSTEM THEN CROSSES
THE REGION ON MONDAY INTO MONDAY NIGHT. SOUTHERLY WINDS TO AROUND
25KTS EXPECTED OVER EASTERN LAKE SUPERIOR ON MONDAY...WITH WINDS
SHIFTING TO WEST-NORTHWEST 20-25 KTS OVER MUCH OF THE LAKE ON
MONDAY NIGHT. W-SW WINDS ARE EXPECTED TO BE LESS THAN 20KTS
TUESDAY AND WEDNESDAY.
&&

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

$$

SHORT TERM...JLA
LONG TERM...MRD
AVIATION...KC/JLA
MARINE...JLA






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