Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 191731
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
131 PM EDT SAT JUL 19 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 536 AM EDT SAT JUL 19 2014

PER WATER VAPOR IMAGERY AND RUC ANALYSIS...VIGOROUS SHORTWAVE THAT
WAS ALONG THE ALBERTA/SASKATCHEWAN BORDER 24HRS AGO IS NOW JUST NE
OF LAKE WINNIPEG. AT THE SFC...ASSOCIATED LOW PRES WAS LOCATED ALONG
THE MANITOBA/ONTARIO BORDER WITH TRAILING COLD FRONT EXTENDING INTO
FAR NW MN AND THE ERN DAKOTAS. SLOW MOVING NARROW BAND OF SHRA/TSRA
WAS OCCURRING AHEAD OF THE FRONT FROM NCNTRL MN INTO ADJACENT
ONTARIO.

MAIN FCST CONCERN TODAY/TONIGHT IS POTENTIAL FOR ISOLD SHRA/TSRA AS
SHORTWAVE NE OF LAKE WINNIPEG LIFTS NE TO HUDSON BAY. BECAUSE
SHORTWAVE IS WEAKENING AND LIFTING NE AND BECAUSE ANOTHER SHORTWAVE
IS QUICKLY ON ITS HEALS MOVING ACROSS ALBERTA/SASKATCHEWAN...COLD
FRONT WILL BE DECAYING AS IT MOVES E TOWARD THE UPPER LAKES
TODAY/TONIGHT. AS A RESULT...SHRA/TSRA POTENTIAL WILL BE DIMINISHING
WITH TIME AS TAIL OF SHORTWAVE AND DECAYING COLD FRONT APPROACH.
FCST SOUNDINGS SHOW THAT MID LEVEL CAP THAT PREVENTED CONVECTION
FROM DEVELOPING YESTERDAY WILL ERODE TODAY...AT LEAST OVER WRN UPPER
MI. SO...THERE IS SOME POTENTIAL FOR CONVECTION TODAY OVER THE W.
GIVEN THE LIMITED COVERAGE OF SHRA/TSRA AHEAD OF FRONT OVER THE LAST
24HRS AND SINCE MAIN FORCING IS LIFTING N OF THE AREA...NOTHING MORE
THAN SCHC TO LOW END CHC POPS APPEAR WARRANTED THIS AFTN OVER THE W.
WITH MLCAPE ONLY INCREASING TO AROUND 500J/KG OR SO AND WITH DEEP
LAYER SHEAR UNDER 25KT...STRONG OR SVR TSTMS ARE NOT EXPECTED. AS
TAIL OF SHORTWAVE AND WEAK DEEP LAYER FORCING MOVE ACROSS THE AREA
TONIGHT...WILL SHIFT A NARROW BAND OF SCHC POPS EASTWARD INTO CNTRL
UPPER MI. AS FOR TEMPS...MIXING TO 850-800MB ON NAM/GFS FCST
SOUNDINGS SUGGESTS MAX TEMPS TODAY WILL BE SIMILAR TO YESTERDAY...
MOSTLY UPPER 70S TO LWR 80S...BUT LOCALLY WARMER IN THE S WIND
DOWNSLOPE AREAS AND COOLER NEAR LAKE MICHIGAN. LOW TEMPS TONIGHT
WILL BE MAINLY IN THE UPPER 50S TO MID 60S.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 501 AM EDT SAT JUL 19 2014

SUN...KEPT THE FORECAST DRY EVEN AS A FEW MODELS SHOWED SOME MINOR
QPF OVER PARTS OF THE CWA ALONG A PASSING VERY WEAK SHORTWAVE. THINK
THAT SHORTWAVE FORCING WILL NOT PROVIDE ENOUGH FORCING TO OVERCOME
DRY AIR.

SUN NIGHT/MON WILL SEE THE UPPER RIDGE BUILDING INTO THE AREA AS
850MB TEMPS INCREASE TO AROUND 22C. MODELS DO SUGGEST THAT RESIDUAL
CONVECTION MAY DECAY AS IT MOVES E INTO THE CWA SUN NIGHT INTO MON
MORNING...BUT AM UNCERTAIN ABOUT THIS OCCURRING. THINK THAT EVEN IF
DECAYING CONVECTION MOVES INTO THE CWA...ENOUGH CLEARING WILL OCCUR
FOR MAX TEMPS TO BE IN THE MID 80S TO AROUND 90 OVER THE W HALF OF
UPPER MI AND IN THE MID 70S TO MID 80S OVER THE EAST HALF.

UNCERTAINTY REMAINS HIGH MON NIGHT INTO TUE NIGHT AS THERE IS
POTENTIAL FOR THUNDERSTORMS THAT MAY FORM OVER THE DAKOTAS ON MON TO
GROW UPSCALE INTO AN MCS THAT MAY MOVE INTO THE CWA LATE MON NIGHT
INTO TUE MORNING...WITH THUNDERSTORMS MOVING E OF THE CWA TUE NIGHT.
ALONG WITH A CONVECTIVE COMPLEX...MODELS SHOW A COLD FRONT MOVING
ACROSS THE CWA DURING THIS TIME. IT DOES APPEAR FAVORABLE FOR
CONVECTIVE ACTIVITY DURING THIS PERIOD DUE TO THE BUILDUP OF
INSTABILITY WITH THE WARM AND VERY HUMID AIR ACROSS THE AREA AND A
40KT LLJ NOSING INTO THE CWA. GENERALLY...MODELS INDICATE OVER
2000J/KG OF ELEVATED CAPE AHEAD OF THE COMPLEX AND COLD FRONT...WITH
PLENTY OF SHEAR AND MID LEVEL LAPSE RATES UP TO 9C/KM. THERE SHOULD
ALSO BE A STOUT CAP OVER THE CWA DURING THIS TIME...BUT IF A STRONG
ENOUGH CONVECTIVE COMPLEX AND/OR COLD FRONT MOVE INTO THE AREA THE
CAP COULD EASILY BE OVERCOME. ALL THIS TO SAY THAT UNCERTAINTY IS
QUITE HIGH...THERE IS A GOOD SHOT AT SEEING CONVECTION...AND THERE
IS CERTAINLY POTENTIAL FOR SEVERE WEATHER /LARGE HAIL AND DAMAGING
WINDS THE PRIMARY CONDITIONAL THREAT/.

COOLER AND DRIER WEATHER LOOKS TO BE IN STORE FOR THE REST OF THE
FORECAST PERIOD AS A SFC HIGH SITS OVER THE CWA AND AN UPPER RIDGE
BUILDS WELL W OF THE REGION.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 130 PM EDT SAT JUL 19 2014

VFR CONDITIONS WILL PREVAIL THRU THE FCST PERIOD AT KIWD/KCMX/KSAW.
AN APPROACHING WEAKENING COLD FRONT AND DISTURBANCE MAY BRING A FEW
SHRA/TSRA INTO WRN UPPER MI THIS AFTN/TONIGHT. HOWEVER...CONFIDENCE
IS TOO LOW TO INCLUDE ANY MENTION OF SHRA DUE TO EXPECTED LIMITED
COVERAGE AND UNCERTAIN LOCATION OF SHRA DEVELOPMENT. IN
ADDITION...GUSTY SOUTH WINDS WILL CONTINUE AT ALL SITES TODAY...WITH
SOME GUSTS AS HIGH AS 20-25 KT.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 536 AM EDT SAT JUL 19 2014

SOUTHERLY WINDS WILL PREVAIL OVER MOST OF LAKE SUPERIOR THRU MON AS
HIGH PRES WILL BE LOCATED TO THE E WHILE A SERIES OF LOW PRES
SYSTEMS/TROFS MOVE ACROSS SRN CANADA. ONE LOW PRES SYSTEM WILL
FINALLY CROSS THE UPPER LAKES TUE BRINGING A WIND SHIFT TO THE N OR
NW. WINDS THRU THE FCST PERIOD WILL GENERALLY BE UNDER 20 KNOTS.
HOWEVER...THERE WILL BE OCNL PERIODS OF SLIGHTLY STRONGER WINDS
(15-25KT) AT THE HIGHER OBS PLATFORMS. THESE STRONGER WINDS WILL
AFFECT MAINLY THE E HALF OF LAKE SUPERIOR. SOME FOG MAY DEVELOP OVER
THE LAKE...ESPECIALLY AFTER SOME PCPN OCCURS. UNTIL THEN...FOG
DEVELOPMENT SHOULD BE CONFINED MOSTLY TO WRN AND NRN PORTIONS OF THE
THE LAKE WHERE FLOW IS MORE CONVERGENT.
&&

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

$$

SHORT TERM...ROLFSON
LONG TERM...TITUS
AVIATION...MRD
MARINE...ROLFSON





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