Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 112031
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
431 PM EDT FRI JUL 11 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 429 PM EDT FRI JUL 11 2014

WV IMAGERY AND RUC ANALYSIS INDICATED A ZONAL PATTERN THROUGH THE
NRN CONUS BETWEEN A TROUGH OVER CNTRL CANADA AND A RIDGE OVER THE
SRN PLAINS. A WEAK SHORTWAVE TROUGH OVER LAKE SUPERIOR INTO CNTRL
UPPER MI HELPED PRODUCE SOME LIGHT SHOWERS ACROSS THE CWA TODAY.
SCT/ISOLD SHRA/TSRA FROM NEAR KINL INTO N CNTRL MN HAD DEVELOPED
ALONG A COLD FRONT/TROUGH AHEAD OF ANOTHER WEAK SHRTWV MOVING
THROUGH NORTH DAKOTA. MOSTLY CLOUDY SKIES OVER UPPER MI HAD LIMITED
TEMPS TO THE LOWER TO MID 70S AND LIMITED MLCAPE VALUES TO LESS THAN
400 J/KG.

TONIGHT...EXPECT THAT SHRA/TSRA OVER NRN MN WILL EXPAND IN COVERAGE
AND MOVE TOWARD UPPER MI. HOWEVER...WITH ONLY MARGINAL INSTABILITY
FCST OVER THE AREA...MUCAPE INTO THE 400-800 J/KG RANGE...THE
CONVECTION SHOULD WEAKEN WITH ONLY ISOLD TSRA. SCT SHRA COVERAGE
WITH CHANCE POPS WAS MENTIONED GIVEN THE WEAK FORCING ASSOCIATED
WITH THE FRONT AND SHRTWV SLIDING THROUGH THE NRN GREAT LAKES. THE
REMAINING SHOWERS ARE EXPECTED TO MOVE INTO THE ERN CWA LATE THIS
EVENING AND DIMINISH FROM WEST TO EAST OVERNIGHT.

SATURDAY...THE WEAKENING COLD FRONT THROUGH UPPER MI WILL PROVIDE A
BOUNDARY/FOCUS FOR POTENTIAL SHRA/TSRA DEVELOPMENT...ESPECIALLY WITH
ONSET OF STRONGER DAYTIME HEATING. EXPECT THE GREATEST PCPN COVERAGE
OVER THE SOUTH AND THROUGH ERN UPPER MI WHERE THE HIGHER RES MODELS
SUGGEST THE LOW LEVEL CONV WILL BE STRONGEST. MLCAPE VALUES TO NEAR
1K J/KG...PER GEM-REGIONAL AND GFS COMBINED WITH 0-6KM SHEAR VALUES
OF 35-40 KNOTS COULD SUPPORT SOME STRONG AND POSSIBLY SEVERE STORMS
IF CLOUD DEPENDENT INSTABILITY IS REALIZED. THE MODELS HAVE ALSO SHOWN A
CONSISTENT SIGNAL THAT SHRA/TSRA WILL MOVE INTO WI ASSOCIATED WITH
STRONGER SHORTWAVE TROUGH. THERE IS STILL TIMING/POSITION UNCERTAINTY
ON HOW IT WOULD AFFECT MAINLY SRN UPPER MI BY LATE AFTERNOON.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 418 AM EDT FRI JUL 11 2014

UNCERTAINTY STILL EXISTS FOR THE WEEKEND AS SUBTLE SHORTWAVES AND
CONVECTIVE COMPLEXES MAKE FORECASTING DIFFICULT.

FOR SAT...THE LOW PRESSURE SYSTEM OVER CENTRAL CANADA WILL REMAIN
STATIONARY AS A WEAK COLD FRONT MOVES INTO THE CWA. THE FRONT WILL
BE OVER NWRN UPPER MI AT 12Z SAT AND LOOKS TO WASH OUT AS IT MOVE
FARTHER INTO UPPER MI. THINK THERE COULD BE SCATTERED SHOWERS AND
THUNDERSTORMS ALONG THE FRONT OVER NWRN UPPER MI. AM MORE UNCERTAIN
WITH CONVECTIVE CHANCES OVER CENTRAL/ERN UPPER MI AS MODELS SHOW A
CONVECTIVE COMPLEX MOVING S OF THE CWA SOMETIME LATE SAT AFTERNOON
INTO EARLY SAT NIGHT. THE NAM IS THE FARTHEST N WITH SHOWING THE
COMPLEX SKIRTING THE SERN CWA. WHILE THIS CANNOT BE COMPLETELY RULED
OUT...WENT MORE WITH THE CONSENSUS APPROACH IN KEEPING THE COMPLEX
FARTHER S. DEPENDING ON THE STRENGTH/TRACK/TIMING OF THE COMPLEX /IF
IT FORMS/...CONVECTION MAY OR MAY NOT DEVELOP FARTHER N OVER THE
CENTRAL AND ERN CWA. IF CONVECTION TO THE S IS MORE
MINIMAL...CONVECTION MAY BE ABLE TO STRENGTHEN OVER THE SCENTRAL CWA
WHERE CAPE VALUES MAY EVEN RISE TO NEAR 1000J/KG WITH DEEP LAYER
SHEAR AROUND 40KTS.

A STRONGER COLD FRONT MOVES THROUGH ON SUN...WITH MODEL VARIABILITY
WITH THE TIMING OF THAT FRONT...ALTHOUGH THE MAJORITY OF MODELS HAVE
IT PASSING THROUGH MUCH OF THE AREA IN THE MORNING TO EARLY
AFTERNOON. THIS DOES NOT ALLOW MUCH TIME FOR INSTABILITY TO DEVELOP.
THINK THAT SCATTERED SHOWERS WILL DEVELOP ALONG THE FRONT OVER
MAINLY ERN UPPER MI...WHERE AT LEAST SOME HEATING WILL OCCUR BEFORE
THE FRONT...AND A WEAK SHORTWAVE RIDING ALONG THAT FRONT...PASSES
THROUGH. PRECIP CHANCES PUSH S THROUGH THE DAY ALONG WITH THE FRONT.

BY 12Z MON...THE UPPER LOW THAT WAS OVER CENTRAL CANADA WILL BE NEAR
INL. THE LOW WILL THEN SHIFT SE AND ACROSS THE GENERAL AREA INTO
TUE...AND SHOULD BE E OF THE CWA BY WED AT THE LATEST...WITH THE GFS
MOVING IT OUT FAR FASTER THAN THE ECMWF AND GEM-NH. AS THAT UPPER
LOW MOVES IN ON MON...THE COLD CORE BEING OVERHEAD OR NEARBY
COMBINED WITH THE HEIGHT FALLS AND DYNAMICS OF THE SYSTEM WILL LEAD
TO SCATTERED SHOWERS OVER MUCH OF THE AREA ON MON INTO TUE.

WITH HOW ANOMALOUSLY STRONG THE LOW WILL BE...THE BIG STORY IN THE
LONG TERM IS TEMPERATURES. 850MB TEMPS WILL BE COLDEST ON TUE AT
4-5C...RESULTING IN HIGH TEMPERATURES IN THE LOW 50S /OR POSSIBLE
NOT EVEN REACHING 50/ OVER NRN UPPER MI...WITH HIGHS IN THE LOW 60S
OVER SCENTRAL UPPER MI. RECORD LOW HIGH TEMPS FOR TUE AT NWS
MARQUETTE IS DEGREES...WHICH QUITE LIKELY WILL BE WARMER THAN WHAT
WE SEE ON TUE. IN FACT THE COLDEST HIGH TEMP FOR THE MONTH OF JULY
IS 51...AND THAT IS NOT EVEN OUT OF THE REALM OF POSSIBILITIES TO
TIE OR BREAK. ALTHOUGH TEMPS DO WARM WED AND THU...THEY SHOULD
CONTINUE TO BE BELOW NORMAL.
&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 152 PM EDT FRI JUL 11 2014

A BAND OF LIGHT SHOWERS MOVING THROUGH UPPER MICHIGAN THROUGH EARLY
AFTERNOON IS NOT EXPECTED TO BE HEAVY ENOUGH...PER RADAR TRENDS...TO
REDUCE CONDITIONS TO MVFR. THE NEXT SHOT OF SOME SHRA AND POSSIBLE
TSRA IS EXPECTED THIS EVENING AS A WEAK COLD FRONT APPROACHES FROM
MN. LOCATION AND COVERAGE OF ANY PCPN IS QUITE UNCERTAIN...SO ONLY A
VCNTY SHRA MENTION WAS INCLUDED FOR NOW. LIKE TODAY...CONDITIONS
SHOULD STAY MAINLY VFR INTO SATURDAY MORNING.
&&

.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 429 PM EDT FRI JUL 11 2014

SOUTH WINDS OF UP TO 20 KTS...POSSIBLY 25 KTS AT HIGHER PLATFORMS
ABOVE MARINE LAYER... EXPECTED INTO THIS EVENING WILL DIMINISH
OVERNIGHT WITH WINDS SHIFTING TO SW. AS SCT SHOWERS ASSOCIATED WITH A
WEAK COLD FRONT OR TROUGH MOVE THROUGH LAKE SUPERIOR...FOG WILL BE
POSSIBLE ACROSS THE ENTIRE LAKE WITH THE TROUGH PASSAGE. LIGHT WINDS
WILL CONTINUE THROUGH SUNDAY BEFORE ANOTHER TROUGH PASSES
SOUTHEASTWARD ACROSS LAKE SUPERIOR SUNDAY NIGHT. GUSTY NORTHWEST
WINDS TO 20 KNOTS EXPECTED BEHIND THIS TROUGH EARLY NEXT WEEK AS
HIGH PRESSURE BUILDS OVER THE NORTHERN PLAINS.
&&

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

$$

SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB





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