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000
FXUS63 KMQT 212345
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
745 PM EDT TUE MAY 21 2013

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 357 PM EDT TUE MAY 21 2013

12Z ROABS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SLOW MOVING UPR LO
OVER ERN SDAKOTA BTWN UPR RDG OVER SCENTRAL CANADA AND A RIDGE OFF
THE SE CONUS. BAND OF SHRA/SCT TS THAT IMPACTED THE CWA EARLIER HAS
LIFTED TO THE N ALONG WITH RESPONSIBLE SHRTWV...ALLOWING FOR MAINLY
DRY WX OVER UPR MI EARLY THIS AFTN. BUT SINCE THE CWA IS N OF SFC
WARM FNT IN WI...PLENTY OF LO CLDS LINGER. THERE IS ALSO SOME FOG...
MAINLY NEAR THE COOLER GREAT LKS. ANOTHER DISTURBANCE IS ROTATING N
THRU IOWA ARND THE CLOSED LO. THE APRCH OF THIS DISTURBANCE HAS
RESULTED IN SOME SHRA OVER CENTRAL WI WHERE BREAKS IN THE LO CLDS
ALONG AND S OF WARM FNT HAVE LIFTED SB CAPE 500-1000 J/KG PER SPC
MESOANALYSIS.

MAIN FCST CONCERNS IN THE SHORT TERM ARE SHRA/TS TRENDS ASSOCIATED
WITH SHRTWV IN IOWA AND THEN APRCH OF MAIN UPR LO.

LATE THIS AFTN/TNGT...SHORT RANGE MODELS ARE IN FAIRLY GOOD
AGREEMENT SHOWING SHRA NOW OVER CENTRAL WI DRIFTING ACRS THE WI
BORDER BY 21Z AND THEN CONTINUING TO THE NE. RUC FCST SDNGS MODIFIED
FOR TEMP/DEWPT OF 68/58 YIELDS SBCAPE UP TO 750 J/KG...SO ADDED
MENTION OF TS. RELATIVELY WEAK WINDS SFC-H5 AS WELL AS DEEP
MSTR/SKINNY CAPE WITH PERSISTENT LO CLDS LIMITING DIURNAL HEATING
INDICATE A LO RISK FOR ANY SVR TS...BUT ANY SHRA COULD RESULT IN
SOME HEAVY RA WITH FCST KINX AS HI AS THE UPR 30S. ONCE THE SHRA
MOVE FARTHER TO THE NE AND AWAY FM THE SFC HEATING AREA...ONE MIGHT
EXPECT THESE SHRA TO DIMINISH THRU THE NGT. BUT FCST AREA OF H85-7
FGEN N OF WARM FNT MIGHT ACT TO SUSTAIN THESE SHRA. WL GO WITH HI
CHC-LIKELY POPS THIS EVNG NEAR THE WI BORDER DIMINISHING TO CHCY
POPS TO THE NE. SINCE THE LLVL FLOW IS FCST TO BACK MORE TO THE NE
FOLLOWING THE PASSAGE OF THIS SHRA AREA...EXPECT COOLER LAKE
AIR/SOME FOG TO MOVE BACK INTO THE AREA OVERNGT.

WED...AS CLOSED LO TO THE W BEGINS TO SHIFT FASTER TO THE ESE TO SW
WI BY 00Z THU...AREA OF LARGER SCALE QVECTOR CNVGC WL IMPACT MAINLY
THE AREA NEAR THE WI BORDER BUT WEAKEN WITH TIME AS THE UPR CLO
BEGINS TO OPEN. BAND OF RA ACCOMPANYING AXIS OF SHARPER FGEN OVER
WRN LK SUP/THE WRN ZNS SHOULD THUS SHIFT SLOWLY TO THE SE THRU THE
DAY. ARRIVAL OF DRIER AIR FM THE NW TO THE SE OF EXPANDING HI PRES
OVER SCENTRAL CANADA MIGHT START TO DIMINISH THE PCPN OVER THE FAR W
LATER IN THE DAY. OTRW...LOWERED FCST HI TEMPS TO ACCOUNT FOR STEADY
NE WIND OFF LK SUP AND EXPECTED CLD COVER.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 357 PM EDT TUE MAY 21 2013

AFTER A WET START TO THE WEEK...THE LONG TERM PERIOD LOOKS TO BE
FAIRLY DRY AS CANADIAN HIGH PRESSURE SLIDES THROUGH THE UPPER GREAT
LAKES REGION.

FIRST...THE UPPER TROUGH THAT HAS BEEN INFLUENCING THE WEATHER FOR
THE START OF THE WORK WEEK WILL BE SITUATED OVER WISCONSIN AND IOWA
AND SHIFTING EAST THROUGH THE GREAT LAKES REGION ON WEDNESDAY
NIGHT. MEANWHILE...THE SURFACE LOW WILL BE LOCATED OVER LOWER
MICHIGAN AT 00Z THURSDAY AND BEGIN TO MOVE UP THE ST LAWRENCE
SEAWAY WEDNESDAY NIGHT INTO THURSDAY AS A SHORTWAVE INTENSIFIES THE
LOW. AS THIS OCCURS...HIGH PRESSURE ORIGINATING FROM NORTH CENTRAL
CANADA WILL BE MOVING A RIDGE INTO THE UPPER MISSISSIPPI VALLEY ON
WEDNESDAY NIGHT AND THE UPPER GREAT LAKES ON THURSDAY. WITH THE
UPPER TROUGH AND CLOSE PROXIMITY OF THE LOW...THERE WILL STILL BE
DEEPER MOISTURE AND 850-700MB Q-VECTOR CONVERGENCE OVER THE
SOUTHEAST HALF OF THE CWA. IN ADDITION...WITH THE INCREASING
NORTHERLY 850-700MB FLOW OVER THE AREA MODELS ARE CONSISTENT ON AN
AREA OF FGEN SETUP FROM IRONWOOD THROUGH EASTERN LAKE SUPERIOR AT
00Z THURSDAY. THEN AS THE LOW SHIFTS EAST...THE FGEN WILL SLIDE
SOUTHEAST THROUGH THE NIGHT AND LIKELY EXIT THE MOST IF NOT ALL OF
THE CWA BY 12Z THURSDAY. AT THIS POINT...THINKING THAT THE MOVEMENT
OF THE PRECIPITATION SHOULD KEEP AMOUNTS UNDER A QUARTER OF AN
INCH.

CANADIAN HIGH PRESSURE THEN BECOMES THE DOMINATING FEATURE FOR THE
REST OF THE PERIOD...AS THE AREA IS UNDER NORTHWEST FLOW ALOFT.
THIS DRY CANADIAN AIR AND COOLER NORTHERLY LOW LEVEL WINDS WILL
LEAD TO NICE BUT SLIGHTLY COOLER THAN NORMAL START TO THE MEMORIAL
DAY WEEKEND. THE STRONGEST NORTHERLY FLOW OFF LAKE SUPERIOR WILL BE
ON THURSDAY WITH THE CLOSER PROXIMITY OF THE EXITING LOW. THIS WILL
KEEP TEMPERATURES COOLER THAN MOST OF THE DAYS...WITH HIGHS IN THE
UPPER 40S NEAR LAKE SUPERIOR AND IN THE 50S INLAND. FRIDAY-SUNDAY
WILL BE DOMINATED BY LAKE BREEZES EACH DAY...WITH THE WARMEST
TEMPERATURES OVER THE INTERIOR LOCATIONS /60S/. THERE ARE HINTS OF A
COUPLE WEAK SHORTWAVES MOVING THROUGH THE NORTHWEST FLOW ALOFT
FRI-SUN...BUT WILL THE DRY AIR IN PLACE...WOULDN/T EXPECT MUCH FOR
PRECIPITATION CHANCES. UNDER THE HIGH PRESSURE RIDGE ON THURSDAY
NIGHT...EXPECT TO SEE SOME SUB FREEZING LOWS OVER THE INTERIOR
PORTIONS OF UPPER MICHIGAN. PWAT VALUES AROUND 40 PERCENT OF NORMAL
AND LIGHT WINDS WOULD BE FAVORABLE WELL BELOW NORMAL LOWS. MAV/MET
GUIDANCE PICKING UP ON THIS IDEA WITH LOWS BETWEEN 25-30 OVER THE
WEST AND THAT SEEMS FAIRLY REASONABLE. HAVE TRENDED THAT DIRECTION
AND LOWERED TEMPS OVER THE WEST AROUND 5 DEGREES. FROST/FREEZE
HEADLINES DON/T START UNTIL MEMORIAL DAY...SO THERE WON/T BE ANY
HEADLINES...BUT ANYONE THAT HAS PLANTED EARLY WILL NEED TO PREPARE
FOR A POTENTIAL FROST/FREEZE.

UPPER RIDGING THAT WILL BE NEARLY STATIONARY JUST EAST OF THE
NORTHERN ROCKIES DURING THIS PERIOD WILL BEGIN TO SHIFT EAST ON
SUNDAY NIGHT AS THE UPPER TROUGH OVER THE NEW ENGLAND STATES SHIFTS
EAST INTO THE ATLANTIC. THIS WILL START A GRADUAL WARMING TREND
TOWARDS MEMORIAL DAY AND INTO THE FIRST PART OF NEXT WEEK. IN
ADDITION...IT WILL ALSO BRING BETTER OPPORTUNITIES FOR SHORTWAVES
TO RIDE OVER THE RIDGE AND INTO THE AREA LATER MONDAY AND MORE
LIKELY TOWARDS TUESDAY.
&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 745 PM EDT TUE MAY 21 2013

COOL/MOIST AIR UPSLOPING OFF LAKE SUPERIOR WILL LIKELY RESULT IN
LIFR CONDITIONS AT KIWD/KCMX/KSAW THRU THE NIGHT. EXPECT -SHRA AT
TIMES ALONG WITH SOME -DZ. DRIER AIR MAY BEGIN TO MAKE INROADS FROM
THE N DURING THE DAY WED AS LOW PRES THAT HAS PLAGUED THE AREA IN
RECENT DAYS CONTINUES TO WEAKEN AND HIGH PRES BEGINS TO NOSE S
TOWARD THE UPPER LAKES. IF SO...KCMX SHOULD IMPROVE TO LOW MVFR IN
THE AFTN AND KIWD MAY IMPROVE TO IFR.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 357 PM EDT TUE MAY 21 2013

GIVEN WIDESPREAD AREA OF RA THAT IMPACTED MUCH OF LAKE SUP INTO THIS
MORNING...SOME RECENT SHIP OBS THAT INDICATED LO VISIBILITY...AND
SHALLOW COOL AIRMASS OVER THE LAKE...OPTED TO EXTENDED DENSE FOG
ADVY THRU TONIGHT. ARRIVAL OF DRIER AIR FROM THE NW ON WED WILL
SLOWLY DIMINISH THE FOG. OTHERWISE...NE WINDS UP TO 25 TO 30 KTS...
WITH SOME GALE FORCE GUSTS AT THE HIER PLATFORMS...WILL CONTINUE
STRONGEST OVER WESTERN LAKE SUP WHERE TERRAIN FUNNELING WILL ENHANCE
THE WIND SPEEDS.

GUSTY NORTHERLY WINDS ARE EXPECTED BEHIND THE LOW PRESSURE SYSTEM
ON WEDNESDAY NIGHT INTO THURSDAY...BUT LINGERING WARM AIR ALOFT
SHOULD KEEP WINDS IN 20-25KT RANGE. THEN...A HIGH PRESSURE RIDGE
BUILDING SOUTHEAST OVER THE UPPER GREAT LAKES FOR THURSDAY NIGHT
THROUGH THE WEEKEND WILL BRING LIGHT WINDS TO LAKE SUPERIOR.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
  DENSE FOG ADVISORY UNTIL 6 AM EDT /5 AM CDT/ WEDNESDAY FOR
     LSZ162-243>249-263>267.

LAKE MICHIGAN...
  DENSE FOG ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR LMZ221-248-250.

&&

$$

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