Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 112032
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
432 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 NIGHT THROUGH FRIDAY)
ISSUED AT 431 PM EDT FRI JUL 11 2014

THE MAIN STORY IN THE LONG TERM CONTINUES TO BE THE SEPTEMBER-LIKE
CONDITIONS EXPECTED ACROSS THE UPPER GREAT LAKES EARLY NEXT WEEK.

SATURDAY NIGHT THROUGH SUNDAY NIGHT...A DEEP MID-LEVEL LOW OVER FAR
SOUTHWEST HUDSON BAY WILL CONTINUE ITS TREK SOUTHWARD AT THE
BEGINNING OF THE PERIOD. CONVECTIVE POTENTIAL ACROSS THE SOUTHEAST
HALF FOR SATURDAY NIGHT WILL DEPEND HEAVILY ON BOTH THE AMOUNT OF
DIURNAL HEATING SATURDAY AND THE LOCATION OF THE DECAYING LOW-LEVEL
CONVERGENCE ZONE. WHILE MCS ACTIVITY LOOKS TO BE MOST PRONOUNCED
ALONG THE NOSE OF A DEVELOPING LOW-LEVEL JET ACROSS WI SATURDAY
AFTERNOON AND EVENING...RESIDUAL 305-315K ISENTROPIC LIFT NORTH OF
THE LOW-LEVEL BOUNDARY MAY BE ENOUGH TO TAP INTO REMAINING MUCAPE OF
AROUND 500 J/KG AS NOTED BY BOTH THE 12Z NAM AND 12Z GEM. ANY
THUNDER ACTIVITY SHOULD REMAIN WEAK THIS FAR NORTH GIVEN A STABLE
SFC LAYER AND OVERALL LIMITED INSTABILITY. HOWEVER...A FEW STRONGER
GUSTS CANNOT BE RULED OUT IN THE EARLY EVENING HOURS FAR SOUTH
CENTRAL WITH ANY STORM ROOTED ALONG THE SFC CONVERGENCE ZONE.

A MID-LEVEL TROUGH AXIS ASSOCIATED WITH THE DEEP LOW WILL CROSS THE
CWA FROM WEST TO EAST LATE SATURDAY NIGHT INTO SUNDAY. WITH LITTLE
ADDITIONAL SUPPORT AND GENERALLY DRY CONDITIONS...ONLY SOME ISOLATED
SHOWER ACTIVITY IS EXPECTED. AFTER THE TROUGH PASSAGE ON
SUNDAY...SKIES LOOK TO BECOME MOSTLY CLEAR FOR A 12-18 HOUR WINDOW.
THIS WILL ALLOW FOR INCREASED MIXING ACROSS THE WEST...WITH WESTERLY
GUSTS TO 25 MPH ACROSS THE KEWEENAW.

MONDAY AND TUESDAY...BY MONDAY MORNING...THE MID-LEVEL LOW WILL
SPLIT INTO TWO WAVES OVER ONTARIO. THE EASTERN SEGMENT OVER
SOUTHERN JAMES BAY WILL EJECT NORTHEASTWARD ACROSS QUEBEC THROUGH
MONDAY. MEANWHILE...THE WESTERN SEGMENT WILL BE TRACKING
SOUTHEASTWARD ACROSS THE BOUNDARY WATERS OF MN AROUND 12Z MONDAY.
THIS WESTERN EXTENSION WILL BECOME STACKED UPWARD FROM H7...SO
PROGRESSION OF THE SYSTEM WILL BE QUITE SLOW. THE MID/UPPER-LOW IS
PROGGED TO TRACK FROM NEAR DLH MONDAY AFTERNOON TO NEAR GRB BY
TUESDAY AFTERNOON. GIVEN THE OVERALL DYNAMICS OF THE SYSTEM...THE
ENTIRE AREA SHOULD SEE AT LEAST SOME SHOWERS DURING THE DAY. ONE
LIMITING FACTOR TO COVERAGE IS A PRESENCE OF DEEP MOISTURE. SOMEWHAT
DRY AIR ABOVE H5 SHOULD KEEP SHOWERS LESS WIDESPREAD AWAY FROM THE
LOW CENTER. SOME DIURNAL HEATING ASSISTANCE WILL ALSO ALLOW FOR
GREATER COVERAGE AWAY FROM THE GREAT LAKES. THEREFORE...THE BEST
COVERAGE IS EXPECTED ALONG THE WI BORDER...WHERE LIKELY POPS HAVE
BEEN INTRODUCED.

TEMPS WILL BE QUITE COOL FOR MID-JULY...WITH H8 TEMPS AT OR BELOW
5C. WITH CLOUDY AND SHOWERS AROUND...HIGHS WILL STRUGGLE TO GET OUT
OF THE 50S ACROSS MUCH OF THE CWA BOTH MONDAY AND TUESDAY. SOME
LOCALES ALONG LAKE SUPERIOR MAY EVEN FAIL TO REACH 50. THESE NUMBERS
ARE 25 DEGREES BELOW AVERAGE...AND WILL LIKELY SET RECORD LOW
MAXIMUM TEMPS ACROSS THE AREA.

SHOWERY ACTIVITY WILL CONTINUE INTO TUESDAY WITH THE PASSAGE OF A
DEFORMATION/FGEN REGION ON THE BACKSIDE OF THE MID/UPPER LOW. THESE
SHOWERS WILL BE SLOW TO MOVE EASTWARD AS THE LOW ONLY REACHES
NORTHERN LAKE HURON BY LATE TUESDAY NIGHT.

WEDNESDAY THROUGH FRIDAY...THE GFS ADVERTISES A MUCH QUICKER
DEPARTURE OF THE MID-LEVEL LOW THAN THE ECMWF/GEM. THIS HAS
IMPLICATIONS ON THE AMOUNT OF MOISTURE AVAILABLE FOR CONTINUED CLOUD
COVER AND HIGH TEMPS ACROSS THE AREA. OTHERWISE...THE STOUT RIDGE
ACROSS THE WESTERN STATES AND PROVINCES THAT DEVELOPED IN RESPONSE
TO THE DEEP EASTERN TROUGH WILL BEGIN TO SHIFT ACROSS THE NORTHERN
PLAINS ON THURSDAY AND THE UPPER GREAT LAKES ON FRIDAY. THIS SHOULD
BRING AN OVERALL QUIET PERIOD OF WEATHER WITH A GRADUAL WARMING
TREND INTO THE WEEKEND. TEMPS LOOK TO BE BACK TO JUST BELOW AVERAGE
BY FRIDAY. HOWEVER...A FEW DIURNAL INLAND SHOWERS COULD BE POSSIBLE
WITH RETURN MOISTURE THURSDAY AFTERNOON.
&&

.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...KLUBER
AVIATION...JLB
MARINE...JLB





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