Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 030545
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
145 AM EDT WED SEP 3 2014

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 357 PM EDT TUE SEP 2 2014

A SHORTWAVE MOVED THROUGH WISCONSIN THIS MORNING...WHILE A MORE
PRONOUNCED WAVE AND BASE OF THE UPPER TROUGH IS SHIFTING EAST
THROUGH THE LOWER GREAT LAKES REGION. THIS WAVE LED TO AN AREA OF
MID CLOUDS THAT MOVED THROUGH THE CENTRAL/EASTERN CWA AND INHIBITED
DIURNAL CLOUD DEVELOPMENT FOR A TIME TODAY. LOOKING OUT FROM THE
OFFICE OVER THE LAST COUPLE OF HOURS INDICATED TOWERS DEVELOPING
AND IT JUST NEEDED A LITTLE PUSH. THAT PUSH CAME FROM THE LAKE
SUPERIOR LAKE BREEZE THAT HAS BEEN SLIDING SOUTH INTO NORTHEAST
MARQUETTE AND ALGER COUNTIES. THUS...HAVE SEE SHOWERS DEVELOPING
ALONG THE LAKE BREEZE AND THEY HAVE STRENGTHENED QUICKLY. SPC MESO
ANALYSIS PAGE INDICATING AROUND 500 J/KG OF MLCAPE (AIDED BY STEEPER
LAPSE RATES OF 7C/KM AT 850-700MB) AND 30-35KTS OF EFFECTIVE BULK
SHEAR. THAT SHOULD BE ENOUGH TO HAVE THUNDER AND WITH LOW FREEZING
LEVELS (AROUND 9KFT) THERE IS SOME CONCERN FOR SMALL HAIL. NCAPE
VALUES AROUND 0.08 WHICH INDICATES TALL/SKINNY CAPE AND SHOULD KEEP
IT FROM GROWING TOO LARGE. DCAPE VALUES ONLY LOOK TO BE AROUND
500-600 J/KG...SO THINK THE WIND THREAT WILL BE LIMITED. EXPECT THESE
ISOLATED/SCATTERED SHOWERS AND THUNDERSTORMS TO CONTINUE TO THE EAST
THROUGH THE EARLY EVENING HOURS...AS ADDITIONAL FORCING FROM LAKE
BREEZE CONVERGENCE OVER THE EASTERN HALF OF THE U.P. AIDS
DEVELOPMENT. THEN THEY SHOULD DIMINISH AS DIURNAL HEATING IS LOST.

FARTHER TO THE WEST...ANOTHER SHORTWAVE IS WORKING EAST THROUGH
THE WEST-NORTHWEST FLOW IN SOUTHERN CANADA AND NORTHERN MINNESOTA.
THIS HAS SPARKED SHOWERS AND THUNDERSTORMS IN THOSE AREAS THIS
AFTERNOON AND SOME HAVE EVEN NOSED INTO WESTERN LAKE SUPERIOR. THIS
SHORTWAVE WILL CONTINUE EASTWARD ACROSS LAKE SUPERIOR TONIGHT AND
EXPECT ISOLATED SHOWERS TO CONTINUE EASTWARD WITH IT. THUS...DID
MOVE THE POPS A LITTLE FARTHER SOUTH AND AFFECTING THE KEWEENAW
PENINSULA FOR A TIME TONIGHT. ELSEWHERE...THE COMBINATION OF LOSING
DIURNAL HEATING AND THE INCREASING INFLUENCE OF A HIGH PRESSURE
RIDGE STRETCHING NORTHWEST FROM A HIGH CENTERED NEAR THE MID
ATLANTIC STATES SHOULD LEAD TO A MOSTLY CLEAR SKY TONIGHT AND
CONTINUING INTO WEDNESDAY MORNING. THE PRECIP OUT EAST COULD LEAD
TO PATCHY FOG DEVELOPMENT BUT THINKING IT WILL BE LIMITED DUE TO
INCREASING WINDS/MIXING JUST ABOVE THE SURFACE. LOWS TONIGHT WILL
BE IN THE MID 40S (TRADITIONAL COLD SPOTS) TO THE LOW-MID 50S UNDER
THE GREATER CLOUD COVER NEAR LAKE SUPERIOR. ABUNDANT SUNSHINE TO
START THE DAY ON WEDNESDAY WILL ALLOW FOR MIXING TO 850-825MB.
MIXING THOSE TEMPS TO THE SURFACE WILL PRODUCE HIGHS IN THE UPPER
70S AND LOWER 80S. WILL FOLLOW THAT IDEA FOR MUCH OF CWA WITH THE
INCREASING SOUTH-SOUTHWESTERLY WINDS. THAT WILL HELP SOME OF THE
DOWNSLOPE AREAS NEAR LAKE SUPERIOR TO BE IN THE LOWER 80S.

IN THE AFTERNOON...WILL NEED TO KEEP AN EYE ON THE EVOLUTION OF
CONVECTIONS UPSTREAM IN MINNESOTA AND WESTERN WISCONSIN. A 998MB
SURFACE LOW IN THE DAKOTAS WILL BE STRETCHING A WARM FRONT EAST
ACROSS CENTRAL MINNESOTA ON WEDNESDAY AFTERNOON. EXPECT
SHOWERS/THUNDERSTORMS TO DEVELOP IN THAT AREA DURING THE AFTERNOON
UNDER INCREASING WARM AIR ADVECTION. STORM MOTION AND CORFIDI
VECTORS WOULD INDICATE THE MOVEMENT TO BE MORE EASTERLY AND THINK
THERE IS A GOOD OPPORTUNITY FOR MUCH OF THE STRONGER PRECIP TO STAY
TO THE SOUTHWEST OF THE AREA. DID TREND POPS UP TO SLIGHT CHANCES
OVER THE WESTERN CWA TOWARDS LATE AFTERNOON AND CHANCES OVER THE
WESTERN LAKE...LARGELY DUE TO THE NORTHERN EDGE OF THE RAIN FROM
THE THUNDERSTORMS FARTHER TO THE SOUTHWEST.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 402 PM EDT TUE SEP 2 2014

WEDNESDAY NIGHT AND THURSDAY...
WILL START OUT WEDNESDAY NIGHT WITH MAINLY ZONAL FLOW ALOFT. AN
EMBEDDED SHORTWAVE WILL BE ACROSS MN AT THE TIME...WITH THE SFC LOW
ACROSS THE N AND CENTRAL PLAINS. LOOK FOR THE WARM FRONT TO PUSH
ACROSS UPPER MI OVERNIGHT AS THE SFC LOW SLIDES E...AND STRETCHES
FROM S MANITOBA THROUGH THE RED RIVER VALLEY OF THE N BY DAYBREAK
THURSDAY. STRONG WAA WILL BRING 850MB TEMPS UP TO 17-20C /WARMEST
ALONG THE WI BORDER/ BY 18Z THURSDAY-00Z FRIDAY. 80S LOOK REASONABLE
FOR MANY LOCATIONS /INLAND FROM LAKE MI/. THE SFC LOW WILL SURGE
INTO W CENTRAL ONTARIO BY 00Z FRIDAY...WITH THE COLD FRONT DRAPED
OVER FAR W UPPER MI...WITH SFC DEW POINTS IMPRESSIVELY JUMPING INTO
THE UPPER 60S IF NOT THE LOW 70S
/SHOWN NAM/GFS/AND ECMWF/. PW VALUES WILL RANGE BETWEEN
1.5 TO JUST OVER 2IN. MUCAPE VALUES COULD TOP OUT BETWEEN 2K
AND 3K J/KG DURING THE DAY THURSDAY...WITH TOTAL TOTALS SHOWING THE
POTENTIAL FOR THE POSSIBILITY OF SOME SEVERE THUNDERSTORMS. DESPITE
ALL OF THIS...THE VERY STRONG CAPPING IS A  HUGE CONCERN...AND MAY
KEEP SOME OF THIS UNDER WRAPS. BEST CHANCE OF SEEING SEVERE STORMS
WILL REMAIN S OF THE WI BORDER...UNLESS THE CAP BREAKS ACROSS UPPER
MI. WILL CONTINUE TO MONITOR LATEST FCST MODEL RUNS AND UPDATE THE
FCST AS NEEDED.

THURSDAY NIGHT...
INSTABILITY WILL QUICKLY DIMINISH OVER THE LATE EVENING HOURS...WITH
CONVECTION E OF A LINE FROM BARAGA TO WATERSMEET BY 03Z FRIDAY...AND
MAINLY OF A LINE FROM MARQUETTE TO MENOMINEE BY 06Z FRIDAY. WITH
FAVORABLE UPSLOPE CONDITIONS /LINGERING STRONG W WINDS 10-15KTS/
EXPECT LIGHT SHOWERS TO LINGER OVER THE FAR W THROUGH THE NIGHT.

FRIDAY THROUGH SATURDAY...
COOLER AIR WILL FILTER IN DURING THE DAY FRIDAY...WITH HIGHS TOPPING
OUT IN THE 60S. PATCHY DRIZZLE MAY LINGER THROUGH THE MORNING HOURS
ON NW FLOW NEAR THE SFC. HIGH PRESSURE OVER THE PLAINS STATES WILL
SLOWLY BUILD ACROSS THE UPPER GREAT LAKES FOR AT LEAST THE FIRST
HALF OF THE WEEKEND...WITH DRY WEATHER ANTICIPATED.

SATURDAY NIGHT THROUGH TUESDAY...
A COLD FRONT WILL DIP NEAR THE CWA SATURDAY NIGHT/SUNDAY TIME
PERIOD...EXTENDING FROM A FAIRLY WELL STACKED SFC-500MB LOW TRACKING
ACROSS HUDSON BAY. GIVEN THE SOURCE REGION FEW IF ANY SHOWERS ARE
EXPECTED. THE 02/12Z GFS IS MORE AMBITIOUS THAN THE 02/00Z ECMWF TO
SWEEP THE COLD FRONT THROUGH THE CENTRAL CWA BY DAYBREAK SUNDAY. THE
ECMWF KEEPS IT MAINLY ACROSS N LAKE SUPERIOR. EITHER WAY COLD AIR
WILL LINGER OVERHEAD...WITH NO SIGNIFICANT WARM UP IN SIGHT. HAVE
SLIGHT CHANCE TO CHANCE POPS AGAIN FOR MONDAY NIGHT INTO
TUESDAY...WITH THE NEXT LOW NEARING FROM THE N AND CENTRAL PLAINS
STATES. KEPT TS MENTION OUT OF THIS PERIOD MUCAPE VALUES OVER
200J/KG REMAIN JUST TO THE S OR W OF THE CWA.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 140 AM EDT WED SEP 3 2014

VFR CONDITIONS ARE EXPECTED TO PREVAIL AT KIWD/KCMX/KSAW THRU THE
FCST PERIOD AS LOW LEVELS REMAIN RELATIVELY DRY. HOWEVER...THERE ARE
A COUPLE OF ITEMS OF CONCERN. FIRST...ANOTHER DISTURBANCE IS
CURRENTLY PRODUCING SHRA/ISOLD TSRA OVER NE MN/WRN LAKE SUPERIOR.
THIS PCPN IS EXPECTED TO DIMINISH OVER THE NEXT FEW HRS...SO HAVE
ONLY INCLUDED A VCSH MENTION AT KCMX. THIS EVENING...MORE SHRA/TSRA
SHOULD DEVELOP N OF A WARM FRONT OVER MN/WI. TIMING/LOCATION OF
SHRA/TSRA DEVELOPMENT REMAINS UNCERTAIN...BUT IT APPEARS BY LATE
EVENING...SOME SHRA/TSRA SHOULD BE DEVELOPING INTO WRN UPPER MI AND
LATER CNTRL UPPER MI. GIVEN THE UNCERTAINTY...VCSH WAS INCLUDED LATE
IN THE FCST PERIOD AT ALL TERMINALS WITH POSSIBLE ADDITION OF TSRA
SAVED FOR LATER FORECASTS.

&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 402 PM EDT TUE SEP 2 2014

A HIGH OVER THE MID MS VALLEY WILL SHIFT E INTO THE MID ATLANTIC
STATES TONIGHT AND WEDNESDAY. MEANWHILE...A LOW IN MT WILL SHIFT E
INTO THE DAKOTAS ON WEDNESDAY...BEFORE MOVING NE TO JAMES BAY
BY FRIDAY MORNING. AS THAT OCCURS...IT WILL DRAG A COLD FRONT ACROSS
THE UPPER GREAT LAKES ON THURSDAY NIGHT. W WINDS WILL GUST 25-30KTS
THURSDAY NIGHT...BEFORE CHANGING OUT OF THE NW FRIDAY AND
DIMINISHING W TO E THROUGH THE DAY.

EXPECT A HIGH TO MOVE OVER THE NORTHERN PLAINS ON FRIDAY AND SHIFT
EAST ACROSS THE GREAT LAKES REGION ON SATURDAY AND SUNDAY.
&&

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

$$

SHORT TERM...SRF
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KF







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