Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 281917
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
317 PM EDT MON JUL 28 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM EDT MON JUL 28 2014

UPPER TROUGH AND COOLER WEATHER PATTERN HAS BECOME ESTABLISHED AND
PERSISTS THROUGH THE WEEK. FOR TODAY...PRIMARY SFC LOW PRESSURE
SYSTEM THAT BROUGHT THE SHOWERS AND THUNDERSTORMS TO THE AREA ON
SUNDAY IS TRACKING ACROSS UPSTATE NEW YORK AND NORTHWEST PENNSYLVANIA
EARLY THIS MORNING WHILE HIGH PRESSURE OVER THE CANADIAN PRAIRIES
EXPANDS SOUTH ACROSS THE CENTRAL PLAINS. SCT-BKN MID CLOUDS ARE
QUICKLY FILLING IN FM MINNESOTA ACROSS WESTERN AND NORTH CENTRAL LK
SUPERIOR AND OVER ONTARIO. AT FIRST GLANCE...SETUP INTO TONIGHT
APPEARS TO SUPPORT MAINLY DRY WEATHER. HOWEVER...NEED TO CONSIDER
SHORTWAVE/ENHANCED CLOUD CURRENTLY DROPPING SOUTH ACROSS NORTHEAST
MANITOBA AND FAR NORTHWEST ONTARIO. 00Z RAOB FROM CYYQ IN NORTHERN
MANITOBA INDICATED ONLY NARROW MOIST LAYER AROUND H6 WITH THIS
WAVE...WITH VERY DRY AIR BLO H6. YET UPSTREAM ATTM...NIGHTTIME
SATELLITE FOG PRODUCT DOES SHOW EXPANDING SHROUD OF CLOUD WITH OBS OF
BKN070 AND SCT140. SEEMS THAT AS SHORTWAVE DROPS SOUTH TODAY...BKN
MID CLOUDS WILL SPREAD OVER MUCH OF UPR MICHIGAN. FORECAST SOUNDINGS
INDICATE NAM IS MOST BULLISH ON DEPTH OF MOISTURE /HIGHER RH FM H85
THROUGH H6/ COMPARED TO GFS AND RUC13 /NARROWER AREA OF HIGHER RH
CENTERED ON H7/. A SUBTLE DIFFERENCE FOR SURE...BUT THIS WILL IMPACT
SHOWER POTENTIAL FOR LATER TODAY.

FORCING WITH THE SHORTWAVE DOES NOT APPEAR TO BE THAT STRONG OR
WIDESPREAD AS PVA AND H85-H5 Q-VECTOR CONVERGENCE IS QUITE WEAK WITH
THE WAVE. SEEMS THAT THE H8-H7 LIFT/UVM PRESENT IS MOSTLY DUE TO THE
COLD TEMPS ALOFT ALONG TRACK OF SHORTWAVE. THIS RESULTS IN SOME
MARGINALLY STEEP MID-LEVEL LAPSE RATES AND POCKET OF 50+ TOTAL
TOTALS.

TRENDED TOWARD MORE CLOUDS TODAY WITH THE INCOMING SHORTWAVE. THIS
ADJUSTMENT RESULTED IN A LOWERING OF MAX TEMPS. BASED ON MIXING TO
H9 WITH ONSHORE NORTHWEST FLOW NEAR LK SUPERIOR AND CLOUDS...WENT MID
60S NEAR LK SUPERIOR AND BASED ON MIXING TO H85 HAVE AROUND 70
INLAND. NOW ONTO THE THOSE SHOWER CHANCES. NAM/NCEP WRF-ARW/WRF-NMM
AND LOCAL WRF RUNS INDICATE SCATTERED QPF MAXIMIZING IN THE AFTN
DURING PEAK HEATING. DPROG/DT OF NAM AND GFS INDICATE GOOD RUN TO RUN
CONSISTENCY IN THE LAST FEW MODEL RUNS. SIGNALS MIXED THOUGH AS GEM-
REGIONAL WHICH ONCE SHOWED DECENT QPF HAS BACKED OFF AND THE ECMWF
SHOWS LITTLE QPF. RUC13...WHICH SHOWS A LOT OF MID CLOUDS... LOOKS
SIMILAR TO GEM-REGIONAL WITH LITTLE QPF OVER LAND AREAS OF UPR
MICHIGAN. LOCAL WRF POINTS TO ISOLD SHRA OVER FAR SCNTRL...WHICH DOES
MAKE SENSE AS IT IS FURTHER AWAY FM MODIFICATION/STABILIZATION OFF LK
SUPERIOR. THINKING THE NAM IDEA IS OVERDONE DUE TO HOW IT IS HANDLING
THE DEPTH OF THE MOISTURE AND SINCE IT ALSO HAS TEMPS INTO THE MID
70S WITH DWPNTS IN THE MID 50S RESULTING IN TOO MUCH SFC BASED
INSTABILITY. EVEN SO...A ROUGE SHOWER IS NOT OUT OF THE QUESTION WITH
THE MOISTURE ADVECTION AND SOME HEATING. BY FAR THE BETTER SHOT AT
SHOWERS SHOULD BE LATE THIS AFTN INTO THE EVENING OVER WESTERN LK
SUPERIOR AND WESTERN UPR MICHIGAN DUE TO UVM FM SHORTWAVE/COLD POOL.
SMALL CHANCE OF SHOWERS...QUITE ISOLD IN COVERAGE...SHOULD SLIDE
ACROSS REST OF CWA THROUGH THE NIGHT AS THE SHORTWAVE CROSSES THE
AREA WHILE SHEARING OUT. ANOTHER SHORTWAVE WILL BE MOVING TOWARD
NORTH CENTRAL LK SUPERIOR LATE TONIGHT...BUT THIS WILL MAINLY AFFECT
THE FORECAST INTO TUESDAY.

.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 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 143 PM EDT MON JUL 28 2014

VFR CONDITIONS EXPECTED AT ALL TAF SITES. HAVE VCSH AT CMX TONIGHT
AS A SHORTWAVE MOVES ACROSS THE AREA...WHICH MAY RESULT IN SCATTERED
SHOWERS. THEN HAVE VCSH AT SAW FOR THE LAST PORTION OF THE TAF
PERIOD AS SHOWERS /AND POSSIBLY THUNDER/ MAY DEVELOP NEARBY.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 408 AM EDT MON JUL 28 2014

NORTH TO NORTHWEST WINDS 15-20 KTS LINGER TODAY OVER MAINLY EASTERN
LK SUPERIOR DUE TO TIGHTER PRESSURE GRAIDENT REMAINING IN WAKE OF LOW
PRESSURE CROSSING THE MID-ATLANTIC STATES. HIGH PRESSURE WITH WINDS
LESS THAN 15 KTS EXPECTED THE REST OF THE WEEK.
&&

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

$$

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






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