Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 262012
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
412 PM EDT TUE MAY 26 2015

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 317 AM EDT TUE MAY 26 2015

UPPER AIR PATTERN CONSISTS OF A 500 MB RIDGE OVER THE ERN U.S. WITH
A TROUGH OVER THE CENTRAL PLAINS AND THERE IS A SHORTWAVE OVER THE
UPPER GREAT LAKES. THE TROUGH OVER THE CENTRAL PLAINS HEADS
NORTHEAST AND MOVES INTO THE UPPER GREAT LAKES THIS EVENING AND
TONIGHT.

NAM BRINGS IN SOME DEEPER MOISTURE AND 850-500 MB Q-VECTOR
CONVERGENCE BACK INTO THE U.P. THIS AFTERNOON AND TONIGHT WITH THE
SHORTWAVE MOVING THROUGH THIS EVENING AND TONIGHT. GFS AND ECMWF
SHOW ABOUT THE SAME THING AS WELL. AGREE WITH SPC THINKING OF SLIGHT
RISK IN THE FAR SOUTHERN CWA AND MARGINAL RISK BASICALLY FROM
CRYSTAL FALLS TO MARQUETTE AND EASTWARD LINE AS THERE WILL BE LAKE
BREEZE BOUNDARIES AND THEIR CONVERGENCE TO KICK OFF SOME CONVECTION
LATE THIS MORNING AND EARLY AFTERNOON AS THE SHORTWAVE STARTS TO
AFFECT THE AREA AS WELL. BOUNDARIES COULD SERVE TO ENHANCE SOME OF
THE STORMS AND COULD SEE HEAVY RAINFALL AND HIGH WINDS MOSTLY FOR
THE SEVERE THREAT. THERE COULD ALSO BE SOME SMALL HAIL IN THE
STRONGER CELLS AS ML CAPE GETS UP TO 700 J/KG OR SO. ONLY QUESTION
IS HOW MUCH SURFACE HEATING WILL TAKE PLACE AND NOT CONFIDENT IN
THIS AS THERE IS SOME CLOUDS AND FOG AROUND AND DEPENDING ON HOW
MUCH CONVECTION OCCURS TO THE SOUTH...HIGH CLOUDS FROM THIS COULD
PREVENT HEATING. HAVE THE HIGHEST POPS ACROSS THE CENTRAL AND
EASTERN CWA. HELD ON TO HIGHER POPS TONIGHT AS THE SHORTWAVE MOVES
THROUGH AND DECREASE POPS AFTER MIDNIGHT. COULD SEE ANYWHERE FROM
0.30 TO 1.50 INCHES OF RAIN OUT OF THIS SYSTEM THROUGH TONIGHT WITH
LEAST AMOUNTS IN THE WEST. DID GO WITH CATEGORICAL POPS FOR THE
CENTRAL AND EAST. OTHERWISE...DID NOT MAKE TOO MANY CHANGES TO THE
GOING FORECAST. TEMPERATURES COULD BE A PROBLEM TODAY IF THERE IS
SOME SUNSHINE...WOULD WARM UP PRETTY GOOD. WILL GO MORE PESSIMISTIC
WITH CLOUD COVER FOR NOW AND NOT CHANGE TEMPERATURES.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 411 PM EDT TUE MAY 26 2015

WEDNESDAY NIGHT...THE FRONT WILL BE WELL PAST THE CWA BY WEDNESDAY
EVENING. THE UPPER LEVEL 500MB TROUGH AXIS WILL CONTINUE TO SHIFT TO
THE EAST OF THE U.P. AT THE SAME TIME...THE DEEPER MOISTURE AND
BETTER FORCING WILL SLIDE OUT OF THE AREA ALLOWING ANY LINGERING
SHOWERS OVER THE EAST HALF TO DIMINISH IN THE EVENING HOURS. THIS
BRIEF BREAK WILL BE FAIRLY SHORT LIVED WITH THE NEXT AREA OF LOW
PRESSURE SLIDING INTO THE NORTHERN PLAINS.

THURSDAY THROUGH FRIDAY NIGHT...DURING THE DAY THURSDAY...MUCH OF
THE AREA WILL SEE A CONTINUED BREAK FROM THE RAIN SHOWERS AS THE CWA
WILL CONTINUE TO BE BETWEEN SYSTEMS DURING THAT TIME...WITH THE COLD
FRONT TO THE EAST AND A LOW PRESSURE SYSTEM AND ASSOCIATED COLD
FRONT SLIDING INTO THE NORTHERN PLAINS AND SOUTH CENTRAL CANADA.
MODELS ARE COMING INTO BETTER AGREEMENT WITH LOW PLACEMENT ALONG
WITH COLD FRONT TIMING THURSDAY NIGHT INTO FRIDAY...WITH THE COLD
FRONT MOVING THROUGH DURING PEAK HEATING. THE GFS IS STILL A BIT
MORE PROGRESSIVE WITH THE SYSTEM WHILE THE EC IS A LITTLE SLOWER AT
MOVING THE SYSTEM THROUGH. LATE THURSDAY NIGHT THROUGH FRIDAY
AFTERNOON/EVENING LOOKS TO BE WET WITH SHOWERS AND THUNDERSTORMS
PUSHING INTO THE UPPER GREAT LAKES REGION. ALOFT...A 500 MB TROUGH
WILL PUSH ACROSS THE AREA AROUND THE SAME TIME FRAME...WHILE
LINGERING INTO THE OVERNIGHT HOURS FRIDAY NIGHT AS A RIDGE BEGINS TO
BUILD OVER THE WESTERN CONUS. AS THE FRONT IS EXPECTED TO MOVE IN
DURING PEAK HEATING...MUCAPE VALUES RANGE FROM 500-700 J/KG FROM THE
GFS TO AROUND 800-1100 J/KG FROM THE EC...MAINLY OVER THE INLAND
WEST. OVERALL INSTABILITY WILL BE LARGELY DEPENDENT UPON CLOUD COVER
OR BREAKS IN THE CLOUD COVER AHEAD OF THE SYSTEM. IF SKIES ARE
OVERCAST THROUGH THE DAY THE INSTABILITY WILL BE LOWER...HELPING TO
REDUCE THE SEVERE RISK. SHEAR VALUES ARE PROGGED TO BE AROUND 35 TO
40 KNOTS PERPENDICULAR TO THE FRONT. THE RISK AGAIN WILL BE
CONDITIONAL...DEPENDING LARGELY ON THE PRE-FRONTAL CLOUD COVER. THE
WARMER TEMPERATURES SLIDING ACROSS THE COLD WATERS OF THE GREAT
LAKES WILL ALSO ALLOW WIDESPREAD FOG TO FORM THURSDAY NIGHT INTO
FRIDAY...ESPECIALLY WHEN THE RAIN SHOWERS PUSH OVER THE LAKES.
TRAPPING MOISTURE UNDER A FAIRLY STRONG TEMPERATURE INVERSION AS
NOTED ON BUFKIT SOUNDINGS.

SATURDAY THROUGH THE REMAINING EXTENDED...NICE WEEKEND EXPECTED AS
DRY COOL CANADIAN HIGH PRESSURE IS EXPECTED TO SLIDE ACROSS THE
UPPER GREAT LAKES REGION IN THE WAKE OF THE LOW AND COLD FRONT.
THERE MAY BE A FEW SHOWERS LINGERING SHOWERS OVER THE FAR EAST
SATURDAY MORNING...BUT SHOULD END QUICKLY BY LATE MORNING OR EARLY
AFTERNOON. THE UPPER LEVEL 500MB TROUGH AXIS WILL SHIFT TO THE EAST
OF THE AREA BY SATURDAY EVENING AND OUT OF THE AREA BY SUNDAY. CALM
WINDS ASSOCIATED WITH THE SURFACE HIGH ALONG WITH VERY DRY AIR IN
PLACE WILL ALLOW TEMPERATURES TO DROP BELOW NORMAL...INTO THE 30S
FOR OVERNIGHT LOW TEMPERATURES AND HIGHS IN THE MID 50S TO LOW 60S.
FROST WILL LIKELY DEVELOP SATURDAY NIGHT INTO SUNDAY MORNING ACROSS
INLAND AREAS. THE NEXT AREA OF LOW PRESSURE IS PROGGED TO DEVELOP
OVER THE NORTHERN PLAINS MONDAY NIGHT AND SLOWLY SHIFT EASTWARD INTO
THE UPPER GREAT LAKES LATE TUESDAY. THERE ARE CONSIDERABLE
DIFFERENCES WITH TIMING AND PLACEMENT OF THIS SYSTEM SO CONFIDENCE
IN RAIN CHANCES IS LOW. CONSENSUS OF THE MODELS BROUGHT LIKELY POPS
IN BUT DECIDED TO ADJUST THEM BACK TO CHANCE POPS WITH THE
AFOREMENTIONED ISSUES IN MIND.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 156 PM EDT TUE MAY 26 2015

A SHORTWAVE TROUGH APPROACHING FROM THE SSW WILL BRING SHRA TO THE
AREA BY MID AFTERNOON THAT WILL LINGER TONIGHT. SOME TSRA MAY BE
POSSIBLE IN CNTRL UPPER MI AFFECTING SAW AS WELL...BUT PROBABILIATY
IS TOO SMALL TO PUT INTO TAFS FOR NOW. IFR/LIFR CONDITIONS ARE
EXPECTED AGAIN BY LATE THIS EVENING AT ALL TERMINALS WITH SOME
UPSLOPE FLOW AND ABUNDANT LOW LEVEL MOISTURE REMAINING. ALTHOUGH VSBY
AT CMX MAY DROP BLO 1SM...THE RAIN WILL HELP LIMIT POTENTIAL FOR MORE
DENSE FOG AOB LANDING MINIMUMS.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 317 AM EDT TUE MAY 26 2015

WINDS ARE EXPECTED TO STAY AT OR BELOW 20 KNOTS FOR MOST OF THIS
FORECAST PERIOD WITH THE EXCEPTION OF FRI NIGHT INTO SATURDAY WHERE
THEY WILL BE UP TO 25 KNOTS ACROSS EASTERN LAKE SUPERIOR. FOG WILL
LINGER THROUGH WEDNESDAY MORNING AND MAY BE DENSE AT TIMES.
ADDITIONAL FOG IS EXPECTED TO DEVELOP THURSDAY NIGHT AND FRIDAY
AHEAD OF THE NEXT LOW AND ASSOCIATED COLD FRONT.
&&

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

$$

SHORT TERM...07
LONG TERM...KEC
AVIATION...JLB
MARINE...07



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