Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 300842
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
442 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...(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 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...MRD
AVIATION...KC/JLA
MARINE...TITUS






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