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000
FXUS63 KMQT 200906
AFDMQT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MARQUETTE MI
506 AM EDT THU JUN 20 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 506 AM EDT THU JUN 20 2013

AS EXPECTED...WITH THE LOSS OF INSTABILITY...MUCH CONVECTION FROM
THE SHOWERS OVER NE MN HAVE TURNED TO MAINLY SHOWERS OVER LAKE
SUPERIOR AND THE KEWEENAW PENINSULA...OUT OF A 6-10KFT CEILING. AN
OUTFLOW BOUNDARY SINKING ACROSS THE KEWEENAW PENINSULA PRIOR TO 06Z
WAS ABLE TO PRODUCE WIND GUSTS NEAR 20KTS...AND CLOSER TO 25KTS
ACROSS GRANITE ISLAND. LIGHTER WINDS HAVE BEEN REALIZED AS IT MOVED
THROUGH MARQUETTE...ISHPEMING AND NEGAUNEE AROUND 7Z.

UPPER MI WILL REMAIN ON THE EASTERN EDGE...JUST OUTSIDE OF THE SPC
SLIGHT RISK FOR TODAY THROUGH TONIGHT. WILL CONTINUE TO MONITOR
SHOWER AND THUNDERSTORM ACTIVITY AS IT BECOMES A BIT MORE ROBUST
LATER THIS MORNING THROUGH THE MID AFTERNOON HOURS...MAINLY ACROSS
INTERIOR W PORTIONS OF UPPER MI. THE SOURCE REGION...CURRENTLY OVER
SE ND...HAS BEEN BRINGING SLOW MOVING SHOWERS AND THUNDERSTORMS TO
THAT AREA ASSOCIATED WITH THE NEXT SHORTWAVE. ML CAPE VALUES SHOULD
JUMP UP TO 500-800J/KG ACROSS WELL INLAND AREAS OF WESTERN UPPER MI
NEAR THE WI BORDER BY 15-18Z...WITH FREEZING LEVELS NEAR 11.8KFT.
SMALL HAIL...HEAVY RAIN...AND BRIEF GUSTY WINDS SHOULD BE THE RESULT
OF MOST STRONGER STORMS THAT DEVELOP TODAY.

EXPECT A SIZABLE BREAK FROM THE SHOWERS AND THUNDERSTORMS FROM JUST
PAST 00Z FRIDAY UNTIL THE NEXT ROUND GETS ORGANIZED AFTER 09-12Z
FRIDAY. THIS WILL BE THE MAIN STORY WITH THE POTENTIAL FOR MORE
WIDESPREAD-STRONGER STORMS. THE CANADIAN IS STARTING TO BECOME
BACKED BY THE REST OF THE SOLUTIONS...WITH A MAJORITY OF THE STORMS
CROSSING LAKE SUPERIOR AFTER 06Z...AND REACHING MUCH OF THE WESTERN
CWA AT OR SLIGHTLY AFTER THE END OF THIS PERIOD...ON STRENGTHENING S
FLOW.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 452 AM EDT THU JUN 20 2013

CONVECTION WILL MAKE FOR A CHALLENGING AND UNCERTAIN FORECAST FRI
THROUGH AT LEAST THE WEEKEND.

AN UPPER RIDGE WILL BUILD E OVER THE AREA FRIDAY THROUGH THE
WEEKEND. AT THE SFC...A LOW WILL REMAIN FAIRLY STATIONARY OVER THE
CENTRAL PLAINS AND EXTENDING FROM THE LOW A WARM FRONT WILL BECOME
POSITIONED ACROSS THE UPPER MS VALLEY AND UPPER GREAT LAKES REGION
THROUGH THE WEEKEND. CONFIDENCE REMAINS LOW WITH THE EXACT
TRACK/TIMING OF CONVECTIVE COMPLEXES DEVELOPING AND MOVING ALONG OR
NEAR THE WARM FRONT. MODELS CONTINUE TO SHOW DIFFERING SCENARIOS FOR
CONVECTIVE DEVELOPMENT AND MOVEMENT...WHICH DEPEND LARGELY ON
NORTHWARD EXTENT OF WARM FRONT. THE GFS AND EVEN THE NAM ARE MOST
AGGRESSIVE WITH NORTHWARD EXTENT OF WARM FRONT ON FRI BRINGING IT AS
FAR NORTH AS LAKE SUPERIOR OR NRN UPPER MI WHILE THE REG GEM AND
ECMWF KEEP THE WARM FRONT JUST TO THE SOUTH OVER WI. NOT
SURPRISINGLY...THE GFS AND NAM INDICATE A CONVECTIVE COMPLEX
BUILDING CLOSER TO MN/CANADIAN BDR TONIGHT WITH MUCH OF THE HEAVIER
PCPN/STORMS MOVING OVER LAKE SUPERIOR AND N CNTRL UPPER MI LATE
TONIGHT INTO FRIDAY. MEANWHILE...THE REGIONAL GEM AND ECMWF SHOW
STORM COMPLEX DEVELOPING CLOSER TO CENTRAL MN AND THEN MOVING ESE IN
LINE WITH FORWARD PROPAGATING CORFIDI VECTORS AND 850-300 MB
THICKNESS LINES ACROSS THE CWA LATE TONIGHT AND FRIDAY WITH THE
HEAVIEST PCPN AND STRONGEST STORMS STAYING CLOSER TO THE WI BDR.
WILL TEND LEAN CLOSER TO THE REG GEM AND ECMWF SOLNS KEEPING THREAT
OF HEAVIER PCPN AND STRONGEST STORMS CLOSER TO THE WI BDR ON FRIDAY
WHICH ALSO FITS WELL WITH SPC DAY2 OUTLOOK. THERE COULD BE A SLIGHT
RISK OF SVR STORMS ON FRIDAY ALONG THE WI BDR WHERE THE GEM AND NAM
INDICATES MLCAPE VALUES BTWN 1000-1500 J/KG. GFS MLCAPE VALUES OF
2000-3000 J/KG OVER THE WRN HALF OF THE CWA ON FRI LOOK OVERBLOWN
WHICH MAY BE DUE IN PART TO THE FARTHER NORTHWARD EXTENT OF THE WARM
FRONT. REGARDLESS...WILL HIGHLIGHT LIKELY TO CATEGORICAL POPS FOR
SHRA/TSRA ACROSS THE CWA ON FRI WITH GREATEST POPS AND GREATEST
THREAT FOR SVR STORMS OVER SCNTRL CWA. THERE IS A POTENTIAL FOR
HEAVY RAIN WITH THE THUNDERSTORMS AS PWATS WILL BE 150-180 PERCENT
OF NORMAL.

FRI NIGHT...AFTER FRI STORM COMPLEX EXITS THE ERN CWA FRI EVENING...
CONSENSUS OF MODELS SUGGEST PERHAPS A BREAK IN CONVECTION BY LATE
FRI EVENING BEFORE MORE CONVECTION FIRES FRI NIGHT OVER CNTRL MN AT
NOSE OF 30 KT 8H JET AND THEN MOVES EAST ACROSS NRN WI INTO SCNTRL
UPPER MI LATE FRI NIGHT/EARLY SAT. GIVEN INCREASED CONFIDENCE IN
MODELS WILL HIGHLIGHT HIGHER POPS SCNTRL FOR LATE FRI NIGHT/EARLY
SAT.

MODELS SHOW EVEN GREATER UNCERTAINTY WITH CONVECTIVE EVOLUTION SAT
INTO SUN SO WILL LIKELY CONTINUE TO CARRY CHC POPS DURING THIS TIME
FRAME. ECMWF AND GEM-NH SUGGEST THERE IS A POTENTIAL FOR ANOTHER
STORM COMPLEX TO MOVE THROUGH THE AREA SAT NIGHT INTO SUNDAY AS
ANOTHER SHORTWAVE RIPPLES THROUGH THE MID-LVL RDG...SO WILL INCLUDE
HIGHER CHC POPS FOR THE SAT NIGHT AND SUN TIME PERIODS. FCST
CONFIDENCE CONTINUES TO WANE FOR THE EARLY TO MIDDLE PART OF NEXT
WEEK AS MEDIUM RANGE MODELS DISPLAY POOR CONTINUITY AND AGREEMENT ON
TIMING OF SHORTWAVE FEATURES. HOWEVER...IT DOES APPEAR THAT CHC POPS
FOR SHRA/TSRA WILL BE WARRANTED THROUGH MUCH OF THE PERIOD AS
PERIODIC SHORTWAVES WORK ON THE WARM AND HUMID AIRMASS WHICH WILL
REMAIN IN PLACE THROUGH AT LEAST TUE.

WITH MODEL CONSENSUS 18-20C 8H TEMPS OVER THE AREA FROM SAT
AFTERNOON THROUGH TUESDAY...EXPECT VERY WARM AND MUGGY CONDITIONS TO
PERSIST FROM THE WEEKEND INTO THE EARLY PORTION OF NEXT WEEK. WOULD
NOT BE SHOCKED TO SEE INLAND HIGHS...ESPECIALLY OVER THE WRN CWA IN
A WEAK TO MODERATE S-SW FLOW...TO RISE WELL INTO THE 80S AND PERHAPS
EVEN PUSH 90F AT A FEW LOCATIONS EVEN WITH THE PERIODS OF CONVECTION
FCST.
&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1209 AM EDT THU JUN 20 2013

OVERNIGHT...ATTENTION TURNS TO SFC TROF DROPPING S TOWARD THE UPPER
LAKES IN ASSOCIATION WITH SHORTWAVE CURRENTLY PASSING THRU NRN
ONTARIO. SCT SHRA AND DIMINISHING TSRA HAVE BEEN OCCURRING
ALONG/AHEAD OF TROF...AND SOME OF THOSE SHRA WILL HOLD TOGETHER AND
AFFECT KCMX OVERNIGHT AND THEN POSSIBLY KIWD/KSAW THIS MORNING.
CONFIDENCE IN SHRA OCCURRING AT KIWD/KSAW IS LOWER THAN AT KCMX...SO
ONLY VCSH WAS UTILIZED AT THOSE 2 TERMINALS. DESPITE -SHRA...INITIAL
DRIER AIR AT THE LOW-LEVELS SHOULD RESULT IN VFR CONDITIONS INTO THE
MORNING. HOWEVER...WILL NEED TO WATCH KCMX AS ANY UPSLOPE WIND OFF
THE LAKE COULD RESULT IN LOWER CLOUDS/FOG POSSIBLY FORMING THIS
MORNING. THIS AFTN...DAYTIME HEATING SHOULD GENERATE SCT SHRA/TSRA
ACROSS UPPER MI WITH BETTER POTENTIAL AT KIWD/KSAW. THERE IS LIMITED
CONFIDENCE IN PCPN ACTUALLY OCCURRING AT A TERMINAL...SO ONLY VCTS
WAS INCLUDED IN FCST. IF SHRA/TSRA OCCUR AT KIWD/KSAW...MVFR
CONDITIONS WOULD LIKELY ACCOMPANY PCPN. SCT CONVECTION SHOULD END BY
EVENING. DURING THE EVENING...COMBINATION OF A COOL EASTERLY UPSLOPE
WIND OFF THE LAKE INTO HIGHER DWPT AIR OVER THE KEWEENAW MAY RESULT
IN FOG/STRATUS DEVELOPING AT KCMX.
&&

.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 354 AM EDT THU JUN 20 2013

FOG...AND ANY STRONGER STORMS /WITH WINDS AND/OR SMALL HAIL/ WILL BE
THE MAIN THREATS THROUGH THE WEEKEND. OTHERWISE WINDS SHOULD REMAIN
AT OR BELOW 25KTS.

A TROUGH OF ACROSS LAKE SUPERIOR WILL...DEEPEN FRIDAY NIGHT...AND
AGAIN SUNDAY THROUGH MONDAY. THIS WILL BE IN RESPONSE TO AN
ELONGATED AREA OF LOW PRESSURE STRETCHING FROM SOUTHWESTERN CANADA
THROUGH EASTERN COLORADO. EXPECT THE AREA OF LOW PRESSURE TO
CONSOLIDATE ACROSS THE CENTRAL PLAINS ON SATURDAY...BEFORE SHIFTING
INTO MANITOBA ON SUNDAY...AND EXITING EASTWARD THROUGH ONTARIO ON
MONDAY.
&&

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

$$

SHORT TERM...KF
LONG TERM...VOSS
AVIATION...ROLFSON
MARINE...KF