Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 290541
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
141 AM EDT TUE JUL 29 2014

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 343 PM EDT MON JUL 28 2014

CURRENTLY THERE IS A DEEP UPPER LOW OVER NRN QUEBEC WITH A DEEP
TROUGH EXTENDING ACROSS MUCH OF THE ERN CONUS. OVER THE WRN CONUS
SITS AN AMPLIFIED RIDGE. AT THE SFC...THE CWA IS BETWEEN A 1027MB
HIGH THAT STRETCHES FROM THE CENTRAL PLAINS THROUGH SASKATCHEWAN AND
A 997MB LOW OVER NEW ENGLAND. A COUPLE PIECES OF ENERGY ROTATING
AROUND THE UPPER LOW ARE UPSTREAM OF THE CWA AND WILL IMPACT THE
AREA OVER THE NEXT 36 HOURS. THE FIRST IS JUST NNW OF LAKE SUPERIOR
AND IS PRODUCING SCATTERED SHOWERS JUST N OF LAKE SUPERIOR. THE
SECOND...WHICH IS STRONGER AND ASSOCIATED WITH A WEAK SFC
TROUGH...IS CURRENTLY OVER NRN ONTARIO AND W OF JAMES BAY.

THE FIRST SHORTWAVE WILL MOVE ACROSS THE WRN CWA THIS EVENING INTO
EARLY TONIGHT...BUT IS ONLY EXPECTED TO PRODUCE SOME ISOLATED TO
POSSIBLY SCATTERED SHOWERS AND THUNDERSTORMS. EXPECT LESS COVERAGE
OF PRECIP OVER THE CWA THAN IN CANADA DUE TO THE CWA BEING DOWNWIND
OF LAKE SUPERIOR AND SINCE THE SHORTWAVE ARRIVES AFTER PEAK
HEATING...BOTH OF WHICH WILL LEAD TO LESS INSTABILITY. BEST CHANCES
WILL BE OVER NWRN UPPER MI.

THE SECOND SHORTWAVE MOVES OVER THE CWA ON TUE...RESULTING IN STEEP
MID LEVEL LAPSE RATES. STILL APPEARS THAT CAPE VALUES WILL TOP OUT
AT 200-700J/KG AND WILL BE SKINNY. 0-6KM SHEAR LOOKS TO BE 20-25KTS
AND SHOULD BE UNIDIRECTIONAL. EXPECTATION IS TO AVOID SEVERE WEATHER
FOR THE MOST PART GIVEN LIMITED INSTABILITY AND WEAK SHEAR...BUT
COULD SEE A COUPLE OF MARGINALLY SEVERE HAIL STORMS AT BEST. BEST
INSTABILITY BEING OVER THE SCENTRAL PUTS THAT AREA UNDER THE BEST
POPS AND SHOULD BE THE LOCATION OF THE STRONGEST STORMS.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 315 PM EDT MON JUL 28 2014

NW FLOW WILL BE THE RULE THROUGH AT LEAST MONDAY OF NEXT WEEK.
DIURNAL SHOWERS AND THUNDERSTORMS STILL LOOK REASONABLE. 850MB TEMPS
WILL HOVER BETWEEN 13C FAR W TO 6C FAR E THROUGH AT LEAST THURSDAY
NIGHT...WITH SIMILAR TEMPS EACH DAY. DAYTIME HIGHS WILL RANGE FROM
THE UPPER 60S TO MID 70S...A LITTLE BELOW NORMAL FOR THIS TIME OF
YEAR THANKS TO THE COOL 850MB READINGS AND PERSISTENT N OR NW FLOW.

THE START OF THE PERIOD WILL BE DOMINATED BY A LARGE 500MB LOW SET
UP ACROSS JAMES BAY...EXTENDING A TROUGH ACROSS THE E HALF OF OF THE
U.S. LOOK FOR A SIZABLE RIDGE OVER THE W HALF OF THE CONTINENTAL
U.S./UP THROUGH ALBERTA AND SASKATCHEWAN.

THE 500MB LOW WILL PUSH AS FAR S AS S JAMES BAY/AND THE E HALF OF
ONTARIO WEDNESDAY INTO THURSDAY...PROMPTING HIGH CHANCE POPS W AND
CENTRAL THURSDAY AFTERNOON. EXPECT SOME WAA ON GENERALLY WESTERLY
FLOW SFC-850MB THURSDAY NIGHT. HOWEVER...WITH THE MAIN LOW NEARING
THE CWA AND A DECENT SHORTWAVE PUSHING IN/WEAK SFC TROUGH LINGERING
OVERHEAD...SFC TEMPS WILL LIKELY NOT JUMP UP TOO MUCH THANKS TO THE
INCREASE IN CLOUD COVER AND SLIGHTLY BETTER CHANCE OF PRECIP.

THE 500MB LOW WILL FINALLY SHIFT E INTO QUEBEC ON FRIDAY...AND EJECT
TO FAR N QUEBEC FRIDAY NIGHT. STRONGER HIGH PRESSURE AT THE SFC
/OVER S CENTRAL CANADA SATURDAY NIGHT/ LOOKS TO BUILD ACROSS THE
UPPER GREAT LAKES SUNDAY NIGHT INTO MONDAY. THERE COULD STILL BE A
WAVE OF TWO ALLOWING FOR A CHANCE OF SHOWERS EVEN ON MONDAY. THE GFS
AND ECMWF BOTH SHOW THE POTENTIAL FOR CONVECTION ENDING OVER THE SE
SUNDAY NIGHT.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 140 AM EDT TUE JUL 29 2014

EXPECT SCT-BKN SHOWERS TO IMPACT MAINLY IWD AND CMX THIS MRNG IN
ADVANCE OF AN UPR DISTURANCE AND UNDER AXIS OF SOMEWHAT MOISTER/
MORE UNSTABLE AIR. ALTHOUGH VFR CONDITIONS WL PREDOMINATE...LOWER
VSBYS ARE PSBL UNDER SOME OF THE HEAVIER SHOWERS. SINCE RA HAS
FALLEN AT IWD AND CMX...SOME FOG MAY LOWER VSBYS THERE TOWARD
SUNRISE IF THERE IS ENUF CLRG AT THOSE SITES. ANOTHER ROUND OF
SHOWERS AND SOME TS WL IMPACT THE SITES LATER TODAY WITH THE APRCH
OF ANOTHER DISTURBANCE IN THE PRESENCE OF DAYTIME HEATING. THERE IS
TOO MUCH UNCERTAINTY ON TIMING/PLACEMENT OF TS TO INCLUDE AN
EXPLICIT MENTION OF TS ATTM. BEST SHOT AT KCMX WOULD BE MID MORNING
TO EARLY AFTN...WHILE IT WOULD BE SLIGHTLY LATER AT KIWD. ALTHOUGH
MVFR AND EVEN IFR CONDITIONS ARE PSBL UNDER SOME OF THE HEAVIER
SHOWERS...VFR CONDITIONS WL PREDOMINATE. DRYING/SUBSIDENCE IN THE
WAKE OF THIS DISTURBANCE WL END THE SHOWER THREAT LATE IN THE
AFTN/EVNG.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE) ISSUED AT
725 PM EDT MON JUL 28 2014

WITH A WEAK PRESSURE GRADIENT TYPICAL OF SUMMER DOMINATING THIS
FORECAST PERIOD...EXPECT WINDS UNDER 20 KTS THRU THE WEEK.
&&

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

$$

SHORT TERM...TITUS
LONG TERM...KF
AVIATION...KC/JLA
MARINE...KC




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