Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 210936
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
536 AM EDT MON JUL 21 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 535 AM EDT MON JUL 21 2014

WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW A RIDGE EXTENDING FROM NRN
MEXICO INTO THE WCNTRL PLAINS. A SHORTWAVE WAS MOVING ACROSS NRN
MANITOBA. ASSOCIATED SFC LOW WAS OVER NE MANITOBA WITH TRAILING COLD
FRONT EXTENDING THRU THE WRN PORTION OF NRN ONTARIO AND THEN SW INTO
NW MN AND ND. WITH STRONGER 850MB FLOW IN RESPONSE TO SHORTWAVE
CONFINED MOSTLY TO NRN ONTARIO...SHRA/TSRA HAVE BEEN OCCURRING
MAINLY IN NRN ONTARIO OVERNIGHT WITH SRN END OF CONVECTION AT TIMES
ACROSS THE BORDER IN FAR NRN MN. RECENT RADAR IMAGERY SHOWS A FEW
SHRA NOW DEVELOPING OVER LAKE SUPERIOR BTWN THE KEWEENAW AND ISLE
ROYALE. WELL OUT TO THE W...A SHORTWAVE WAS LIFTING OUT OF THE GREAT
BASIN. THIS FEATURE WILL TRIGGER SVR STORMS THIS AFTN OVER ND WITH
STORMS EVOLVING INTO AN MCS THAT WILL AFFECT THE UPPER LAKES LATE
TONIGHT/TUE.

AS TAIL END OF STRONGER 850MB FLOW SHIFTS E ACROSS LAKE SUPERIOR
THIS MORNING/EARLY AFTN...MAY SEE ISOLD SHRA/TSTMS SPREAD ACROSS
PORTIONS OF NW AND NCNTRL UPPER MI. RECENT SHRA DEVELOPMENT BTWN THE
KEWEENAW AND ISLE ROYALE PROVIDES SOME CONFIDENCE FOR THE POTENTIAL
OF ISOLD CONVECTION FARTHER E AS THE MORNING PROGRESSES. OVERNIGHT
HIGH RES RAPID REFRESH MODEL RUNS HAVE BEEN INSISTENT ON GREATER
COVERAGE OF CONVECTIVE DEVELOPMENT FARTHER S INTO UPPER MI THIS
MORNING. SEEMS OVERDONE...BUT WILL BE SOMETHING TO MONITOR. AS WIND
FIELDS WEAKEN THIS AFTN...LAKE BREEZE MAY SLIP ONSHORE OVER
PORTIONS OF NCNTL UPPER MI. IF SO...NOT OUT OF THE QUESTION THAT A
AN ISOLD TSTM OR TWO COULD DEVELOP ALONG THE BOUNDARY WITHIN
MOIST/UNSTABLE ENVIRONMENT. OTHERWISE...EXPECT PARTLY TO MOSTLY
SUNNY SKIES TODAY ALONG WITH UNCOMFORTABLY HUMID CONDITIONS AS SFC
DWPTS RISE WELL INTO THE 60S...TO AROUND 70F LOCALLY. MIXING TO
AROUND 850MB OR SO ON FCST SOUNDINGS YIELDS MAX TEMPS GENERALLY IN
THE MID TO UPPER 80S. IT WILL BE LOCALLY WARMER WHERE SOUTHERLY
WINDS DOWNSLOPE...AND ONCE AGAIN...IT WILL BE COOLER NEAR LAKE
MICHIGAN...ESPECIALLY E OF KESC.

TONIGHT...ATTENTION TURNS TO SVR STORMS DEVELOPING IN ND THAT WILL
GROW UPSCALE INTO AN MCS IN RESPONSE TO SHORTWAVE MOVING OUT OF THE
ROCKIES AND ACROSS THE NRN PLAINS TOWARD THE UPPER LAKES. MODELS ARE
IN GOOD AGREEMENT ON DEVELOPING CONVECTION OVER ND THIS AFTN.
HOWEVER...AS TIME PROGRESSES...MODELS DIVERGE ON THE EVOLUTION OF
STORMS AND LIKELY MCS TONIGHT INTO TUE MORNING. GIVEN TRACK OF
SHORTWAVE AND POOL OF ELAVATED INSTABILITY ACROSS MN/WI AVBL FOR
STORMS TO TAKE ADVANTAGE OF OVERNIGHT...BELIEVE THE NCEP ARW/NMM AND
NSSL WRF OFFER THE MOST VIABLE SOLUTIONS OF WHAT WILL TRANSPIRE.
THOSE MODELS SHOW TSTMS SPREADING INTO FAR WRN UPPER MI AFT 06Z AND
REACHING CNTRL UPPER MI BY 12Z. WHILE OVERNIGHT TIMING SUGGESTS
STORMS WILL BE WEAKENING AS THEY ARRIVE...DEGREE OF INSTABILITY AVBL
FOR INFLOW MAY STILL SUPPORT SOME SVR THREAT AT LEAST INTO FAR WRN
UPPER MI.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 442 PM EDT SUN JUL 20 2014

MONDAY NIGHT INTO TUESDAY UPPER MI WILL BE SANDWICHED IN A WEAK
TROUGH BETWEEN TWO SURFACE HIGH PRESSURE CENTERS...ONE OVER THE MID
ATLANTIC AND THE OTHER OVER THE CANADIAN PRAIRIES. ALOFT...STRONG
HIGH PRESSURE IS ANCHORED OVER NEW MEXICO AND THE MID ATLANTIC...AND
LOW PRESSURE IS SITUATED OVER HUDSON BAY. AS A RESULT...500MB FLOW
OVER THE NORTHERN PLAINS AND UPPER MI IS SOMEWHAT ZONAL. A POTENT
SHORTWAVE WILL KICK OFF CONVECTION IN THE NORTHERN PLAINS BY LATE
MONDAY AFTERNOON. THIS CONVECTIVE COMPLEX WILL BE THE MAIN FEATURE
OF INTEREST FOR THE LONG TERM FORECAST.

HAVE LIKELY TO CATEGORICAL POPS THROUGH THE CWA MONDAY NIGHT INTO
TUESDAY. MUCAPE VALUES SHOW EXTREME INSTABILITY BY U.P. STANDARDS
ACROSS THE WESTERN U.P. MONDAY EVENING /00Z TUE. MUCAPE VALUES ARE
FORECAST TO BE UPWARDS OF 3000 J/KG...AND MORE LIKE 1000 J/KG IN THE
EAST. THIS IS CONDITIONAL THOUGH...GIVEN THE ENVIRONMENT WILL BE
LARGELY CAPPED WITH THE RIDGE IN PLACE. HOWEVER...ISENTROPIC ASCENT
ON THE 315K SFC AHEAD OF THE DEVELOPING SURFACE LOW...AND A 25 TO 35
KNOT LL JET OVER SOUTHERN MN/WESTERN WI/IOWA WILL SUPPORT AN
ENVIRONMENT FAVORABLE FOR SUSTAINING ANY INCOMING MCS AND FOR
DEVELOPING ELEVATED CONVECTION AFTER 00Z TUE. 0-6 KM/1-6KM SHEAR IS
FAVORABLE FOR MCS SUSTAINABILITY/TSTORMS DEVELOPMENT AS
WELL...AROUND 25-40 KNOTS THROUGH MUCH OF TUESDAY. WITH A SHALLOW
STABLE LAYER AT THE SURFACE...THINKING SOME SEVERE LEVEL WIND GUSTS
AND HAIL ARE A SIGNIFICANT POSSIBILITY. THE BEST CHANCES WILL BE
OVERNIGHT MONDAY AND THROUGH EARLY TUESDAY MORNING ACROSS THE WEST
AND CENTRAL. AS FAR AS TIMING GOES...EXPECT SHOWERS/STORMS TO MOVE
IN/DEVELOP LATE MONDAY EVENING /3Z/ OUT WEST...AND CONTINUE TO MOVE
EASTWARD THROUGH TUESDAY...THOUGH SEVERE POTENTIAL DIMINISHES AS
THINGS PROGRESS EASTWARD. GENERALLY THE BETTER INSTABILITY
DIMINISHES AND BECOMES LARGELY CONFINED TO THE WEST/CENTRAL U.P./WI
BORDER THROUGHOUT THE DAY...AND THE UPPER LEVEL SUPPORT DIMINISHES
AS THE LOW EXITS THE AREA.

LARGE SCALE RIDGING EXTENDING FROM THE HIGH PRESSURE CENTERED OVER
NEW MEXICO WILL SHIFT SLIGHTLY EASTWARD INTO THE MIDWEST...ALLOWING
SURFACE HIGH PRESSURE TO INFILTRATE UPPER MICHIGAN FOR WEDNESDAY
AFTERNOON AND THURSDAY. THIS WILL BRING A COOL DOWN AND DRIER
CONDITIONS TO THE REGION...ESPECIALLY WEDNESDAY WITH NORTHERLY WINDS
OFF LAKE SUPERIOR. 850MB TEMPS WILL BE AROUND 7-10C...SO EXPECT HIGH
TEMPERATURES IN THE 60S AND 70S.

AN UPPER LEVEL LOW WILL MOVE FROM ALBERTA INTO ONTARIO OVER THE
WEEKEND...BRINGING UNSETTLED WEATHER BACK TO THE GREAT LAKES THIS
WEEKEND AND FOR THE START OF NEXT WEEK. HAVE KEPT CHANCE
SHOWERS/TSTORMS FOR NOW. TEMPS LOOK SEASONABLE...WITH HIGHS IN THE
UPPER 60S AND 70S.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 137 AM EDT MON JUL 21 2014

VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE FCST PERIOD AT
KIWD/KCMX/KSAW. THE REMNANTS OF SHRA/TSRA IN NRN MN MAY REACH NW
UPPER MI LATE OVERNIGHT AT CMX. SINCE THE PROBABILITY/CONFIDENCE IS
LOW...IT WAS NOT MENTIONED IN THE TAF AT THIS TIME. ADDITIONAL AREAS
OF TSRA ARE EXPECTED TO DEVELOP THIS EVENING TO THE WEST OF UPPER MI AND
WILL MOVE TOWARD THE AREA...BUT REMAIN WEST OF IWD/CMX THROUGH
06Z/TUE.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 535 AM EDT MON JUL 21 2014

SOUTHERLY WINDS WILL CONTINUE OVER MOST OF LAKE SUPERIOR
TODAY/TONIGHT. WHILE S WINDS WILL BE MOSTLY UNDER 20KT...STRONGER
WINDS/GUSTS INTO THE 20-30KT RANGE WILL LIKELY OCCUR AT THE HIGHER
OBS PLATFORMS...MAINLY THIS MORNING AND MAINLY OVER THE E HALF OF
LAKE SUPERIOR. ON TUE...A LOW PRES SYSTEM WILL PASS ACROSS THE UPPER
LAKES...BRINGING A WIND SHIFT TO THE N. AGAIN...THE STRONGER WINDS
OF 15-25KT WILL LIKELY OCCUR OVER ERN LAKE SUPERIOR. IN ADDITION...
DEPENDING ON STRENGTH/COVERAGE AND EVOLUTION OF TSTMS MOVING ACROSS
LAKE SUPERIOR TONIGHT/TUE AHEAD OF LOW...THERE MAY BE A PERIOD OF
STRONG WINDS ACROSS MUCH OF THE LAKE FOR A TIME LATE TONIGHT AND
TUE. HIGH PRES WILL SETTLE INTO THE GREAT LAKES LATE WED THRU
FRI...PROVIDING A PERIOD OF LIGHT WINDS.

ON A FINAL NOTE...FOG MAY EXPAND ACROSS LAKE SUPERIOR TODAY THRU
TUE...ESPECIALLY ONCE PCPN OCCURS.
&&

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

$$

SHORT TERM...ROLFSON
LONG TERM...MCD
AVIATION...JLB
MARINE...ROLFSON






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