Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 010026
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
826 PM EDT THU JUL 31 2014

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 326 PM EDT THU JUL 31 2014

NOT MUCH OVERALL PATTERN CHANGE IN THE LAST 24 HOURS AS AN UPPER LOW
SPINS NEAR JAMES BAY...SENDING SHORTWAVE ENERGY THROUGH THE REGION
ON A FAIRLY REGULAR BASIS. PREDOMINANT SHORTWAVE RIGHT NOW IS JUST
SW OF THE CWA AND HAS SPARKED SOME LIGHT RAIN SHOWERS NEAR LAKE
MICHIGAN WHERE THE LAKE SUPERIOR AND LAKE MICHIGAN BREEZES HAVE
COLLIDED. NOW THAT MUCH OF THE ERN CWA IS BEING DOMINATED BY THE
COOLER AIR BEHIND THE LAKE BREEZES...MOST DIURNAL SHOWERS HAVE
FADED. OTHERWISE...ANOTHER WEAKER SHORTWAVE IS JUST N OF THE MN
ARROWHEAD...BUT NOTHING MORE THAN A CU FIELD IS OCCURRING WITH
THAT...AND NO ADDITIONAL PRECIP DEVELOPMENT IS EXPECTED AS IT MOVES
ACROSS THE CWA THIS EVENING AND TONIGHT.

THAT SHORTWAVE DOES LOOK TO PRODUCE SOME CLOUD COVER OVER THE ERN
CWA TONIGHT...BUT THE REST OF THE CWA WILL SEE MOSTLY CLEAR SKIES.
AS SUCH...LOWS WILL BE IN THE MID 40S TO LOW 50S. COULD SEE SOME FOG
FORM INLAND TONIGHT AS WELL.

YET ANOTHER SHORTWAVE...A LITTLE MORE POTENT THAN THE ONE CURRENTLY
SW OF THE CWA...WILL MOVE AGAIN ACROSS OR SLIGHTLY SW OF THE CWA FRI
AFTERNOON/EVENING. THIS SHOULD ALLOW FOR GREATER DEVELOPMENT OF
CONVECTION THAN WHAT WE HAVE SEEN TODAY DUE TO A PLUME OF HIGHER
MOISTURE THAT WILL MOVE IN. BEST AREA FOR CONVECTION APPEARS TO BE
OVER THE SCENTRAL AND ALONG LAKE MICHIGAN WHERE LAKE BREEZE
CONVERGENCE WILL PROVIDE ADDITIONAL FORCING FOR ASCENT. MLCAPE
VALUES LOOK TO BE 400-800J/KG OVER THE AFOREMENTIONED FAVORED AREAS
AND 0-6KM BULK SHEAR SHOULD BE 20-25KTS. WITH THIS...COULD SEE SOME
STORM ORGANIZATION...BUT SHOULD ONLY BE TO THE POINT OF SOME PEA
SIZED HAIL AT WORST.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 336 PM EDT THU JUL 31 2014

BOTH THE GFS/ECMWF HAVE THE PERSISTENT 500MB LOW PRESSURE SYSTEM
RESPONSIBLE FOR COOL AND UNSETTLED WEATHER OVER MUCH OF THE GREAT
LAKES THIS WEEK LIFTING NORTHEASTWARD INTO QUEBEC BY SATURDAY
EVENING. UNFORTUNATELY...THE RIDGE ANCHORED OVER THE SOUTHWESTERN
U.S. WILL EXPAND EASTWARD THROUGH THE MIDDLE OF NEXT WEEK...AND HIGH
PRESSURE OVER THE ATLANTIC WILL REMAIN FIRMLY IN PLACE. THIS WILL
KEEP THE GREAT LAKES UNDERNEATH EITHER AN UPPER LEVEL TROUGH OR
FAIRLY ZONAL FLOW FOR THE LONG TERM FORECAST PERIOD. WHILE
TEMPERATURES WILL NOT BE AS COOL AS THIS PAST WEEK...THEY WILL
STRUGGLE TO REACH THE MID-UPPER 70S NEXT WEEK.

PRECIPITATION CHANCES THIS WEEKEND/NEXT WEEK WILL BE CONFINED TO THE
VARIOUS SHORTWAVES THAT PROGRESS THROUGH THE ZONAL FLOW. FRIDAY
EVENING ANY REMAINING ISOLATED SHOWERS/THUNDERSTORMS ARE EXPECTED TO
DWINDLE AFTER DAYTIME HEATING IS LOST...WITH AROUND 1K-2K J/KG OF
MUCAPE...0-6KM SHEAR OF 15-20 KTS...AND DIMINISHING MOISTURE
AVAILABLE LATE FRIDAY AFTERNOON INTO THE EARLY EVENING. A BRIEF SFC
HIGH PRESSURE/WEAK RIDGE WILL CROSS UPPER MI DURING THE DAY
SATURDAY...KEEPING CONDITIONS DRY. HOWEVER...WITH SUBSIDENCE AND THE
NIGHTTIME INVERSION DEVELOPING FRIDAY EVENING...DEWPOINT DEPRESSIONS
ARE LESS THAN 2 DEGREES OVER MAINLY NORTH CENTRAL/EASTERN LAKE
SUPERIOR AND EASTERN UPPER MI. WITH LIGHT WINDS AND DECREASING CLOUD
COVER FRIDAY NIGHT KEPT PATCHY FOG IN THE FORECAST FOR THESE AREAS.
EXPECT PATCHY FOG OVER LAND TO DIMINISH BY LATE SATURDAY
MORNING...BUT LINGER OVER LAKE SUPERIOR THROUGH THE WEEK.
OTHERWISE...SATURDAY SHOULD BE FAIRLY SEASONABLE AND WARMER...WITH
HIGHS IN THE 70S FOR MOST LOCATIONS.

THE FIRST SHORTWAVE TO IMPACT THE AREA ARRIVES LATE SATURDAY NIGHT
INTO SUNDAY. IN RESPONSE...A WEAK SURFACE LOW DEVELOPS OVER ONTARIO
AND DRIFTS STEADILY SOUTHEAST OF JAMES BAY BY MONDAY MORNING. THIS
WILL BRING A WEAK COLD FRONT/TROUGH ACROSS UPPER MICHIGAN SUNDAY
BEFORE WEAK SURFACE HIGH PRESSURE RE-ESTABLISHES ITSELF OVER THE
REGION. ANOTHER WEAK SURFACE LOW DEVELOPS ALONG THE TROUGH OVER
SOUTH DAKOTA/NEBRASKA AROUND THE SAME TIME...AND THIS LOW STRUGGLES
TO MAINTAIN ITSELF AS IT MOVES INTO IOWA/MN SUNDAY EVENING WITH THE
BUILDING HIGH PRESSURE RIDGE ALOFT.

MODELS HAVE THE COLD FRONT ADVANCING ACROSS UPPER MI FROM WEST TO
EAST SUNDAY MORNING INTO MONDAY MORNING...THOUGH THEY DIFFER WITH
RESPECT TO TIMING. BOTH MODELS HAVE WEAK 700-850MB MOISTURE
CONVERGENCE AND MUCAPES MAXING OUT AROUND 1500-2000 J/KG...WITH
0-6KM SHEAR OUT WEST REACHING UP TO AROUND 20KTS OUT WEST AS A SMALL
300MB JET NOSES INTO THE CWA. THE GFS AS USUAL IS MORE
PROGRESSIVE...WITH THE FRONT SITUATED OVER CENTRAL UPPER MI 12Z
SUNDAY...AND EASTERN UPPER MI BY 18Z SUNDAY. THE ECMWF SLOWS THINGS
DOWN...WITH THE FRONT OVER CENTRAL UPPER MI BY 18Z SUNDAY AND
EASTERN UPPER MI LATE SUNDAY EVENING. IF THE FRONT COMES THROUGH IN
THE AFTERNOON AS THE ECMWF SUGGESTS THINK THE AMALGAMATION OF DECENT
MOISTURE/LIFT/INSTABILITY AND SHEAR WILL PROVIDE THE BEST
REINFORCEMENT FOR SHOWERS/T-STORM DEVELOPMENT. WILL STICK WITH THE
GOING CHANCE POPS/SLIGHT CHANCE POPS FOR SUNDAY...WITH BEST CHANCES
WEST WHERE THE BEST INSTABILITY/SHEAR IS LOCATED. WOULD NOT BE
SURPRISED TO SEE A COUPLE STRONGER STORMS DEVELOP IF THE ECMWF IS ON
THE RIGHT TRACK.

FOR THE START OF THE WORK WEEK...UPPER MI IS AT THE MERCY OF PASSING
SHORTWAVES THROUGH THE SOMEWHAT ZONAL FLOW ALOFT...SO HAVE KEPT
CONSENSUS CHANCE/SLIGHT CHANCE POPS FOR NOW...MAINLY ON MONDAY.
SURFACE HIGH PRESSURE SETTLES IN OVER UPPER MI ON TUESDAY...SO MOST
OF THE CWA WILL REMAIN DRY. A WARM FRONT ASSOCIATED WITH DEVELOPING
LOW PRESSURE OVER SOUTH DAKOTA WILL LIFT NORTHWARD OVER SOUTHERN
MN/WI TUESDAY AFTERNOON INTO TUESDAY EVENING...BUT THINKING
PRECIPITATION CHANCES WILL BE CONFINED TO THE WI BORDER AND FAR
SOUTHWESTERN CWA FOR NOW. LIGHT NORTHERLY WINDS BEHIND THE COLD
FRONT WILL KEEP TEMPERATURES BELOW NORMAL...WITH HIGHS IN THE UPPER
60S AND 70S. WEDNESDAY INTO THURSDAY THE UPPER LEVEL TROUGH DEEPENS
AS A POTENT SHORTWAVE DIVES INTO THE GREAT LAKES. THIS BRINGS THE
SURFACE LOW FROM SOUTH DAKOTA INTO CENTRAL LAKE MI BY THURSDAY
AFTERNOON AND THE NEXT CHANCES FOR PRECIPITATION TO THE CWA.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 824 PM EDT THU JUL 31 2014

VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. LIGHT LAKE BREEZES
WILL DEVELOP AT THE TAF SITES ON FRIDAY. &&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 326 PM EDT THU JUL 31 2014

WITH A WEAK PRESSURE GRADIENT TYPICAL OF SUMMER DOMINATING THIS
FORECAST PERIOD...EXPECT WINDS UNDER 15 KTS THROUGH MONDAY.

THERE IS THE POTENTIAL FOR PATCHY FOG OVER THE NEXT SEVERAL
DAYS FOR PORTIONS OF LAKE SUPERIOR...BUT DON/T EXPECT ANY
WIDESPREAD DENSE FOG AT THIS TIME.
&&

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

$$

SHORT TERM...TITUS
LONG TERM...MCD
AVIATION...VOSS
MARINE...TITUS






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