Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 271741
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
141 PM EDT SAT JUN 27 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 246 AM EDT SAT JUN 27 2015

UPPER AIR PATTERN CONSISTS OF 500 MB RIDGE ACROSS THE ROCKIES AND
TROUGHING IN THE LOWER GREAT LAKES WITH A CLOSED 500 MB LOW OVER
SOUTHERN LAKE MICHIGAN. THERE IS ALSO A SHORTWAVE TOPPING THE RIDGE
OVER SASKATCHEWAN. THE SHORTWAVE OVER SASKATCHEWAN DROPS SSE TODAY
WHILE THE UPPER LOW MOVES SLOWLY EAST AND THE U.P. STAYS BETWEEN
BOTH SYSTEMS FOR THIS FORECAST WITH ONE TO THE SE AND THE OTHER
STAYING TO THE WEST.

DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST AND KEPT IT DRY
UNTIL LATE TONIGHT WHEN PUT IN SLIGHT CHANCE POPS IN THE FAR WEST AS
THE SHORTWAVE PASSES TO THE WEST OF THE AREA AND THE BEST DYNAMICS
AND MOISTURE STAY WELL WEST OF THE AREA. GOING TEMPERATURES LOOKED
GOOD AND MADE VERY FEW CHANGES.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 230 AM EDT SAT JUN 27 2015

IMPACT ASSESSMENT...MOST IMPACTFUL WEATHER WILL BE MON AS SOME
STRONGER THUNDERSTORMS MAY RESULT AND ALSO FRI INTO NEXT WEEKEND DUE
TO INCREASE IN OUTDOOR ACTIVITIES RELATED TO INDEPENDENCE DAY.
GREATEST FOCUS WAS PUT INTO THESE TIMES.

A BROAD UPPER TROUGH WILL BE OVER THE ERN HALF OF THE CONUS SUN
THROUGH MID WEEK. MODELS SHOW A SHORTWAVE MOVING W OF THE CWA ON SUN
AND DRAGGING A SFC TROUGH ALONG WITH IT. FORCING MAY BE SUFFICIENT
FOR SHOWERS AND THUNDERSTORMS MAINLY SUN AFTERNOON/EVENING OVER WRN
UPPER MI. CAPE MAY EXCEED 1000J/KG SUN AFTERNOON/EARLY EVENING...BUT
0-6KM BULK SHEAR VALUES WILL BE LESS THAN 10KTS...SO NO SEVERE
STORMS ARE ANTICIPATED.

SLIGHT CHANCES FOR SHOWERS AND THUNDERSTORMS WILL REMAIN IN THE
FORECAST FOR THE W ON SUN NIGHT AS THE SFC TROUGH SITS OVER WRN
UPPER MI.

TIMING AND TRACK OF A SHORTWAVE MODELS SHOW MOVING THROUGH ON MON
WILL BE IMPORTANT TO CONVECTIVE STRENGTH...ALTHOUGH MOST LOCATIONS
SHOULD AT LEAST SEE PRECIP. WHILE THERE IS SOME UNCERTAINTY...MODELS
GENERALLY SHOW THE SHORTWAVE FIRING CONVECTION STARTING IN THE EARLY
AFTERNOON AND CONTINUE INTO THE EARLY EVENING. CAPE IN EXCESS OF
1000J/KG APPEARS LIKELY IF ENOUGH SFC HEATING CAN RESULT. THE ECMWF
IS ON THE LOW SIDE OF CAPE VALUES WITH SBCAPE AROUND 1000J/KG ALONG
THE WI BORDER...BUT THE NAM AND GFS SHOW 1500-2000J/KG OF SBCAPE IN
THE AFTERNOON. BIG NEGATIVE FOR SEVERE STORMS IS 0-6KM BULK SHEAR
VALUES OF 10-15KTS...SO LAKE BREEZE INTERACTION WILL BE KEY FOR
HAVING ORGANIZED STORMS. WILL NEED TO KEEP AN EYE ON CONDITIONS FOR
MON.

SHOWER AND POSSIBLY THUNDER CHANCES CONTINUE INTO MON NIGHT AS
ANOTHER WEAKER WAVE POSSIBLE MOVES THROUGH. SHOULD SEE CLEARING BY
TUE EVENING AS SFC HIGH PRESSURE PUSHES IN FROM THE N...BUT THERE IS
UNCERTAINTY ON HOW FAST CLEARING OCCURS.

WED THROUGH AT LEAST MOST OF THU LOOK DRY AS A 1020MB HIGH MOVES
THROUGH. IT WILL BE COOLER WITH 850MB TEMPS IN THE MID SINGLE
DIGITS...RESULTING IN HIGHS MAINLY IN THE 60S ON WED.

NOW FOR THE FRI AND SAT TIME PERIOD. MODEL RUN TO RUN CONTINUITY HAS
BEEN POOR ON EXACT TIMING OF A SHORTWAVE AND SUBSEQUENT UPPER TROUGH
LATE IN THE WEEK/NEXT WEEKEND. THE ECMWF HAS A STRONG SHORTWAVE AND
ASSOCIATED WIDESPREAD PRECIP MOVING THROUGH THU NIGHT INTO FRI...THE
GFS IS WEAKER WITH LESS QPF AND LATER (FRI AFTERNOON INTO FRI
NIGHT). BEST IDEA FOR NOW IS CHANCES OF SHOWERS ON FRI. MODELS AGREE
BETTER THAT AN UPPER TROUGH WILL SWING INTO THE AREA ON
SAT...BRINGING QPF INTO THE AREA...ALTHOUGH MODELS DISAGREE ON THE
EXTENT OF THE PRECIP. COOLER AIRMASS MOVES IN WITH THE UPPER TROUGH
SAT INTO SUN...WITH MODELS SHOWING 850MB TEMPS IN THE LOW SINGLE
DIGITS. THE GFS IS SLOWING IN BRINGING IN THOSE COLDER TEMPS...SO
THERE IS UNCERTAINTY THERE AS WELL. THINK PRECIP CHANCES ARE LOWER
ON SAT THAN FRI...WITH SLIGHT CHANCE TO MAYBE LOW CHANCE REASONABLE.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 137 PM EDT SAT JUN 27 2015

VFR CONDITIONS AND LIGHT WINDS WILL CONTINUE INTO SUNDAY MORNING.
ISOLATED SHOWERS OR THUNDERSTORMS MAY DEVELOP AT ALL TAF SITES ON
SUNDAY AFTERNOON DUE TO DAYTIME HEATING/INSTABILITY AND APPROACH OF
AN UPPER LEVEL DISTURBANCE. EVEN WITH A SHRA OR TSRA...CONDITIONS ARE
EXPECTED TO REMAIN VFR AT ALL TAF SITES. &&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 246 AM EDT SAT JUN 27 2015

HIGH PRESSURE OVER LAKE SUPERIOR WILL LEAD TO WINDS STAYING BELOW
20KTS THROUGH THE WEEKEND. A SERIES OF WEAK TROUGHS WILL DROP
SOUTHEAST ACROSS LAKE SUPERIOR LATE SUNDAY INTO EARLY NEXT
WEEK...BUT WINDS ARE STILL EXPECTED TO STAY BELOW 20KTS. FOG IS
POSSIBLE OVER THE LAKE...BUT COVERAGE WILL STAY PATCHY THROUGH
TODAY.
&&

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

$$

SHORT TERM...07
LONG TERM...TITUS
AVIATION...JLA
MARINE...07



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