652 
FXUS63 KMQT 261740
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
1240 PM EST TUE FEB 26 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM EST TUE FEB 26 2013

00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW PATTERN 
ACRS NAMERICA...WITH THE UPR GRT LKS UNDER A POLAR JET STREAM WELL S 
OF ARCTIC BRANCH IN CENTRL CANADA THAT HAS CONFINED THE BITTERLY 
COLD ARCTIC AIR TO FAR NRN CANADA. AN ACTIVE SUBTROPICAL BRANCH 
DOMINATES THE S HALF OF THE CONUS...WITH A POTENT DISTURBANCE MOVING 
INTO THE LOWER-MID MS RIVER VALLEY. A DISTURBANCE WITHIN THE POLAR 
BRANCH IS MOVING ACRS UPR MI EARLY THIS MRNG...BUT LIMITED MSTR 
DEPTH PER 00Z GRB/APX RAOBS AND GENERAL LARGER SCALE ACYC FLOW 
RELATED TO RDG AXIS EXTENDING WWD FM HI CENTER IN SE CANADA HAS 
RESTRICTED ANY IMPACT TO AN AREA OF SC. THE BACK EDGE OF THIS CLD 
AREA IS JUST INLAND FM THE W SHORE OF UPR MI CLOSER TO INCOMING AREA 
OF DRY AIR DEPICTED ON THE 00Z INL/MPX RAOBS AND WHICH IS UNDER 
DNVA/LARGE SCALE QVECTOR DVGC BEHIND THE SHRTWV. SKIES OVER FAR NW 
WI/WRN LK SUP AND THE MN ARROWHEAD OF MOCLR...WHICH HAS ALLOWED SOME 
FOG TO FORM WITH LGT WINDS. HI CLDS ON THE NRN EDGE OF THE 
SUBTROPICAL BRANCH DISTURBANCE TO THE S ARE SPREADING SLOWLY NWD 
THRU WI.

MAIN FCST CONCERNS TODAY ARE CLD TRENDS/IMPACT ON TEMPS. FOCUS FOR 
TNGT SHIFTS TO WHETHER ANY PCPN ASSOCIATED WITH SRN BRANCH 
DISTURBANCE WL IMPACT THE SRN CWA.

TODAY...POLAR BRANCH UPR RDG/DNVA/LARGE SCALE QVECTOR DVGC WL 
DOMINATE UPR MI TODAY. AS THE SUBTROPICAL BRANCH SFC LO MOVES INTO 
THE LOWER OH RIVER VALLEY BY 00Z WED...THE PRES GRADIENT WL TIGHTEN 
OVER UPR MI TO THE WSW OF HI CENTERED IN SE CANADA...WITH AN INCRSG 
ENE FLOW. ALTHOUGH THE LARGER SCALE NEGATIVE DYNAMICS WOULD INDICATE 
A SLOW BREAKUP OF THE SC DOMINATAING MUCH OF THE CWA NOW...THIS LO 
CLD IS WIDESPREAD TO THE E OF UPR MI THIS MRNG...THE SOURCE AIRMASS 
FOR THE DVLPG E WIND. ON THE OTHER HAND...THE DIFFLUENT NATURE OF 
THE LLVL FLOW AS WELL AS STRONG SUBSIDENCE FCST AT H925 SHOULD TEND 
TO BREAK UP THE LO CLD. RECENT TRENDS SHOWN ON STLT IMAGERY/SFC OBS 
CONFIRM THIS EXPECTATION. DIURNAL HEATING WITH INCRSG LATE FEB SUN 
ANGLE WL ALSO TEND TO DISSIPATE THE SC OVER THE LAKES AS H85 TEMPS 
ARE FCST TO BE ABOUT -4C...A TYPICAL EARLY SPRING SCENARIO. IN THIS 
SCENARIO...SOME DIURNAL CU/SC WOULD TEND TO FORM OVER THE INTERIOR 
FOLLOWING INITIAL CLRG. THE COVERAGE OF THIS CLD SHOULD BE LIMITED 
BY THE RATHER LO INVRN BASE SHOWN ON NAM/GFS FCST SDNGS. MAINTAINED 
OVERALL FLAVOR OF GOING FCST SHOWING A TERND FOR DECREASING CLDS 
INTO THIS AFTN...WITH A BIT MORE CLD COVER OVER THE INTERIOR... 
ESPECIALLY IN USPLOPE AREAS. MIXING TO H875 ON FCST SDNGS YIELDS HI 
TEMPS CLOSE TO 40...MOST LIKELY IN AREAS OVER THE W THAT SEE MORE 
SUNSHINE AND DOWNSLOPE IN LLVL ENE FLOW AWAY FM THE COOLING 
INFLUENCE OF THE LKS. GOING FCST NEEDS ONLY MINOR ADJUSTMENTS.

TNGT...SUBTROPICAL BRANCH LO IS PROGGED TO MOVE NE INTO OH BY 12Z 
WED. THE BULK OF THE NUMERICAL GUIDANCE SHOWS LGT QPF ON THE NW 
FLANK OF THIS LO PRES BRUSHING JUST THE SE COUNTIES WITH SOME LGT 
PCPN TOWARD 12Z WED...CONSISTENT WITH THE PASSAGE OF THE DEEP LYR 
QVECTOR THRU LWR MI. DESPITE CYC NATURE OF THE INCRSG LLVL NE 
FLOW...H85 TEMPS NO LOWER THAN ABOUT -5C AS WELL AS FCST DRY H85-7 
LYR INDICATE THERE WL BE NO LK EFFECT/ENHANCED PCPN EVEN IF MORE SC 
DVLPS IN THE UPSLOPE AREAS. OPTED TO RETAIN GOING SCHC POPS ONLY 
CLOSE TO LK MI/BAY OF GREEN BAY.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 357 AM EST TUE FEB 26 2013

NOT MUCH IN THE WAY OF PRECIPITATION EXPECTED THROUGH THIS LONG TERM 
PERIOD...WITH MARCH LIKELY COMING IN LIKE A LAMB /AS NOTED ON THE 
PREVIOUS DISCUSSION/.

BY WEDNESDAY THE 500MB LOW WILL BE THE CLOSEST IT WILL GET TO THE 
CWA...TRACKING FROM OHIO TO NE PENNSYLVANIA...SQUEEZING THE RIDGE 
NORTH INTO ONTARIO. EXPECT NE FLOW AT THE SFC AND ALOFT WEDNESDAY. 
THE 25/12Z CONTINUES TO SHOW A SOUTHERLY TREND TO THE TRACK...WITH A 
DOUBLE BARREL LOW SPLITTING THE APPALACHIANS MERGING ACROSS THE NEW 
ENGLAND STATES WEDNESDAY NIGHT. A MEER 24 HOURS AGO THE NAM SOLUTION 
WAS FOR THE SURFACE LOW TO SWING ACROSS CENTRAL LOWER MICHIGAN...NOW 
IT LOOKS TO BE MORE IN LINE IF NOT SLIGHTLY SLOWER THAN THE 
ECMWF/GFS ON WEDNESDAY.

STRONG HIGH PRESSURE STRETCHING ACROSS NORTH CENTRAL CANADA ON 
TUESDAY WILL PUSH INTO HUDSON BAY AND MANITOBA/ONTARIO 
WEDNESDAY/WEDNESDAY NIGHT...WITH THE RIDGE EDGING ACROSS LAKE 
SUPERIOR THURSDAY NIGHT THROUGH AT LEAST SUNDAY MORNING. WE STILL 
EXPECT SOME BREEZY CONDITIONS NEAR THE LAKE SUPERIOR SHORELINE 
WEDNESDAY THROUGH THURSDAY /PUSHING ACROSS MUCH OF CENTRAL UPPER 
MICHIGAN DURING THE DAY THURSDAY/. WINDS WILL SLOWLY DIMINISH AS THE 
LOW CONTINUES TO EXIT EAST AND THE SURFACE HIGH PUSHES OVERHEAD.

AS FOR THE CHANCE OF PRECIPITATION THROUGH THE PERIOD...IT IS PRETTY 
MINIMAL. THE SYNOPTIC SNOW WILL ONLY CLIP AREAS NEAR LAKE MICHIGAN 
WEDNESDAY INTO WEDNESDAY EVENING. EVEN WITH THE FAVORABLE UPSLOPE 
WINDS OFF LAKE SUPERIOR...TEMPERATURES AT AND ABOVE THE SURFACE WILL 
BE MARGINAL TO SUPPORT ANY ACCUMULATING SNOW SHOWERS. 

COLDER AIR WILL FINALLY COME IN FOR THE END OF THE WORK WEEK...WITH 
850MB TEMPERATURES FALLING TO AROUND -11C FRIDAY AFTERNOON...AND -12 
TO -14C FRIDAY NIGHT THROUGH AT LEAST SUNDAY /WITH N-NE WINDS 
CONTINUING THROUGH SATURDAY/. 

THE 25/12Z ECMWF KEEPS THE RIDGE IN PLACE THROUGH TUESDAY...BECOMING 
OUT OF PHASE WITH THE 25/18Z GFS BY MONDAY NIGHT /STRONG 1044MB HIGH 
OVER NORTHERN MANITOBA AND ONTARIO...COMPARED TO THE 1005MB LOW 
ACROSS ONTARIO/. WHILE THE 26/00Z GFS DID COME IT SLIGHTLY BETTER 
AGREEMENT...IT JUST CAN NOT BEAT THE RUN TO RUN CONSISTENCY BEING 
SHOWN BY THE ECMWF. CUT BACK THE SLIGHT CHANCE POPS GIVEN WITH A 
CONSENSUS OF THE MODELS FOR DAY 6/MONDAY TO RIGHT ALONG THE 
WISCONSIN BORDER...MINIMIZING THE INFLUENCE OF THE 26/00Z GFS RUN ON 
THE POPS.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1240 PM EST TUE FEB 26 2013

AT KIWD...EXPECT VFR CONDITIONS THRU THE AFTN. HOWEVER...DAYTIME 
HEATING HAS LEAD TO OCNL BKN CIGS DEVELOPING OVER WRN UPPER MI PER 
SATELLITE IMAGERY. SO THERE MAY BE A FEW PERIODS OF MVFR CIGS THIS 
AFTN AT KIWD. KCMX HAS A SIMILAR SETUP TO KIWD...BUT WILL KEY ON 
LARGE AREA OF STRATOCU OVER ERN LAKE SUPERIOR WHICH IS MAKING STEADY 
PROGRESS WESTWARD. SIMPLE EXTRAPOLATION SUGGESTS MVFR CIGS MAY REACH 
KCMX AROUND 22Z. AT KSAW...EXPECT HIGH MVFR CIGS TO RISE SLIGHTLY TO 
VFR DURING THE AFTN HRS. TONIGHT INTO WED MORNING...LOW PRES MOVING 
TOWARD THE LOWER LAKES WILL CAUSE A CYCLONIC NE FLOW TO STRENGTHEN. 
THIS SHOULD RESULT IN MVFR CIGS DEVELOPING WHERE THIS FLOW MOISTENED 
BY LAKE SUPERIOR WILL UPSLOPE AT KIWD/KSAW.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 357 AM EST TUE FEB 26 2013

A RIDGE OF HIGH PRESSURE ACROSS LAKE SUPERIOR WILL PUSH NORTHWARD 
TODAY...IN ADVANCE OF WEAKENING LOW PRESSURE SLIDING FROM SOUTHERN 
MISSOURI THIS MORNING TO FAR SOUTHEASTERN LOWER MICHIGAN AND OHIO 
WEDNESDAY MORNING...AND EXITING ACROSS NEW YORK WEDNESDAY NIGHT. AS 
A RESULT...EXPECT A TROUGH OVER LAKE SUPERIOR WITH STEADY N-NE WINDS 
FROM MID AFTERNOON THROUGH THE REST OF THE WORK WEEK. THE STRONGEST 
WINDS...WITH A FEW GUSTS NEARING 35KTS CAN BE EXPECTED WEDNESDAY 
INTO THURSDAY AS LAKE SUPERIOR BECOMES PINNED BETWEEN THE LOW 
PRESSURE SYSTEM TO OUR SOUTHEAST AND STRONG HIGH PRESSURE EDGING IN 
FROM THE NORTHWEST. GIVEN THE STRONGER WINDS AND COOLER AIR SLIDING 
IN...FREEZING SPRAY WILL BE POSSIBLE. HIGH PRESSURE WILL WIN OUT 
FRIDAY...WITH A RIDGE RESIDING ACROSS LAKE SUPERIOR THROUGH AT LEAST 
SATURDAY NIGHT.
&&

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

$$

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