Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 300544
AFDMQT

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

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 348 PM EDT FRI AUG 29 2014

AN UPPER TROUGH CURRENTLY EXTENDS FROM WRN MN TO CENTRAL TX...WITH A
SHORTWAVE TROUGH CURRENTLY ALONG THE MT/ND BORDER. AT THE SFC...A
1007MB LOW IS CURRENTLY OVER NWRN MN WITH A SFC WARM FRONT EXTENDING
SE INTO CENTRAL WI. THE 925MB PORTION OF THE WARM FRONT /AS SHOWN IN
MODEL DATA/ IS OVER THE SRN CWA. CURRENT PRECIP IS GREATEST OVER THE
WRN CWA AND INTO WRN WI AND ERN MN CLOSER TO THE SFC LOW AND IN THE
RIGHT ENTRANCE REGION OF THE 300MB JET.

THE SHORTWAVE MOVING IN FROM THE W WILL HELP PUSH THE SYSTEM E
TONIGHT INTO SAT. THE SHORTWAVE WILL MOVE INTO WI BY 18Z SAT AS THE
SFC LOW MOVES TO OR NEAR SCENTRAL UPPER MI...WITH THE SFC LOW MOVING
SE OF THE CWA BY 00Z SUN. EXPECT BEST AREA OF PRECIP TO REMAIN OVER
THE WRN CWA THROUGH THIS EVENING BEFORE THE SFC LOW AND UPPER TROUGH
MOVE E. THE BEST RAIN CHANCES WILL THEN SHIFT FROM W TO E TONIGHT
INTO SAT AS THE LOW /AND ASSOCIATED DEFORMATION AXIS ON THE BACK
SIDE OF THE LOW/ MOVE EAST. HEAVY RAIN WILL REMAIN A
POSSIBILITY...ESPECIALLY AHEAD OF THE LOW WHERE WARM CLOUD DEPTHS
WILL REMAIN AROUND 11KFT...SOME LIMITED INSTABILITY WILL BE
PRESENT...MOVEMENT OF PRECIPITATION WILL BE SLOW...AND PWATS WILL BE
1.5-1.8 INCHES /150-200 PERCENT OF NORMAL/. HAVE ADDITIONAL QPF
AMOUNTS THROUGH SATURDAY OF 0.75-1.5 INCHES /HIGHEST OVER THE
W/...BUT AMOUNTS COULD BE HIGHER IF THUNDERSTORMS TRAIN OVER ANY ONE
AREA. THUNDERSTORMS WILL BE POSSIBLE OVER MUCH OF THE CWA INTO THIS
EVENING AS INSTABILITY NOSES INTO THE AREA BEHIND THE 925MB WARM
FRONT...BUT WILL BE MAINLY FOCUSED ALONG THE SRN CWA TONIGHT AND
ERN CWA SAT. THERE IS ENOUGH CLEARING OVER NERN WI TO TURN MORE
ATTENTION TO THE NAM AND LOCAL HIGH-RES WRF MODELS...WHICH SHOW
MLCAPE INCREASING TO AROUND 2000J/KG OVER FAR SCENTRAL UPPER MI
BEHIND THE SFC WARM FRONT. THINK THAT 2000J/KG MAY BE A BIT TOO HIGH
BUT NOT TOTALLY UNREASONABLE GIVEN CURRENT ANALYZED MUCAPE VALUES
ONLY UP TO 3000J/KG UPSTREAM OVER CENTRAL WI /AND 2000J/KG AT GRB/
WHERE SFC TEMPS ARE IN THE LOW TO MID 80S AND DEW POINTS ARE IN THE
LOW 70S. IF THESE HIGHER CAPE VALUES DO MATERIALIZE...SEVERE STORMS
WOULD BE POSSIBLE WITH DAMAGING WINDS AND A SMALL TORNADO THREAT AS
0-1KM SHEAR WOULD BE 25-30KTS AND 0-6KM SHEAR 35-40KTS WITH DECENT
CURVATURE TO THE HODOGRAPHS...ESPECIALLY IN THE 0-1KM AND 0-3KM
LAYERS. THINK THE HAIL THREAT WOULD BE MORE MINIMIZED BY THE FACT
THAT THE 0C LEVEL SHOULD BE ABOVE 12KFT AND THE -20C LEVEL AROUND
30KFT. WILL NEED TO CONTINUE TO MONITOR SHORT TERM TRENDS FOR SEVERE
POTENTIAL.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 328 PM EDT FRI AUG 29 2014

NAM SHOWS A SHORTWAVE OVER THE UPPER GREAT LAKES 00Z SUN WITH A
TROUGH OVER THE WESTERN U.S. A SHORTWAVE RIDGE MOVES INTO THE UPPER
GREAT LAKES ON SUN WITH TROUGHING MOVING INTO THE NORTHERN PLAINS
AND THIS TROUGH MOVES IN FOR SUN NIGHT INTO MON INTO THE AREA. NAM
BRINGS IN SOME 850-500 MB Q-VECTOR CONVERGENCE AND SOME MOISTURE SUN
NIGHT INTO MON ACROSS THE AREA. GFS AND ECMWF SHOW ABOUT THE SAME
THING AND WILL CONTINUE DIMINISHING POPS TREND FOR SAT NIGHT...DRY
FOR SUN AND THEN INCREASE POPS TO CATEGORICAL FOR SUN NIGHT INTO MON
FOR MOST OF THE CWA. DID NOT MAKE TOO MANY CHANGES TO THE GOING
FORECAST.

IN THE EXTENDED...GFS AND ECMWF SHOW A BROAD 500 MB TROUGH ACROSS
THE NORTHERN HALF OF THE U.S. WITH A RIDGE OVER THE SOUTHERN HALF
12Z TUE. UPPER PATTERN CHANGES LITTLE FOR 12Z WED WITH A STATIONARY
SFC FRONT ACROSS THE MID MISSISSIPPI AND OHIO VALLEYS. THE UPPER
RIDGE STARTS TO BUILD BACK TO THE NORTH 12Z THU AND 12Z FRI WITH A
WARM FRONT MOVING SLOWLY NORTH. WHAT THIS WILL MEAN IS A WARMING
TREND AND IT WILL BE DRY FROM TUE NIGHT THROUGH WED NIGHT BEFORE THE
WARM FRONT STARTS TO AFFECT THE AREA. MODELS SEEM OVERDONE ON POPS
FOR THEN. EVEN TUE...HAVING SOME DOUBTS THAT THERE WILL BE
POPS...BUT COULD SEE WITH UPPER TROUGHING IN THE AREA MAYBE SOME
ISOLATED INSTABILITY SHOWERS AND SLIGHT CHANCE POPS ARE WARRANTED
FOR THEN. TEMPERATURES WILL GO BACK TO NEAR NORMAL.
&&

.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 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 348 PM EDT FRI AUG 29 2014

A LOW PRESSURE SYSTEM WILL SHIFT THROUGH THE REGION TONIGHT INTO
SATURDAY...CHANGING WINDS FROM THE SE TODAY TO THE N-NW TONIGHT INTO
SAT...WHILE WINDS REMAIN BELOW 25KTS. A STRONG LOW PRESSURE SYSTEM
WILL MOVE THROUGH THE REGION ON MONDAY INTO MONDAY NIGHT...AND MAY
RESULT IN SOUTHERLY WINDS TO AROUND 25KTS OVER EASTERN LAKE SUPERIOR
ON MONDAY. 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...TITUS
LONG TERM...07
AVIATION...KC/JLA
MARINE...TITUS









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