AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
900 AM PDT WED APR 9 2008
.SYNOPSIS...
UPPER LEVEL LOW PRESSURE WILL EXIT THE REGION TODAY. SKIES WILL TURN
PARTLY CLOUDY WEST OF THE MOUNTAINS AND WINDS IN THE MOUNTAINS AND
DESERTS WILL DECREASE. HIGH PRESSURE WILL BRING FAIR AND MUCH WARMER
WEATHER THURSDAY THROUGH THE WEEKEND.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
ONLY A FEW HUNDREDTHS OF AN INCH OF RAIN FELL ALONG A STRIP IN
NORTHERN SAN DIEGO CO FROM THE COAST TO THE MTNS EARLY THIS MORNING.
ELSEWHERE IT WAS DRY. SKIES WERE CLEARING OUT FROM NORTHWEST TO
SOUTHEAST THIS MORNING...BUT SHALLOW CONVECTION WILL CONTINUE TO
PRODUCE SOME CLOUDS IN THE MOIST AND RELATIVELY UNSTABLE MARINE
LAYER ESPECIALLY IN THE VALLEYS TODAY. THE MTN AND DESERT WINDS HAVE
DECREASED BELOW ADVISORY CRITERIA SO THE ADVISORY WILL EXPIRE SOON
EVEN THOUGH BRISK WINDS WILL CONTINUE TODAY. A MORE SHALLOW MARINE
LAYER WILL DEVELOP TONIGHT AS WARMER AIR ALOFT STRENGTHENS THE
INVERSION. A HIGH PRESSURE RIDGE WILL AMPLIFY ALONG THE WEST COAST
THU INTO THE WEEKEND BRINGING FAIR AND MUCH WARMER WEATHER. OFFSHORE
FLOW DEVELOPS THU NIGHT...BUT IT WILL PROBABLY NOT BE ENOUGH TO KEEP
FOG COMPLETELY AWAY FROM THE COAST NEAR SAN DIEGO FRI MORNING...BUT
ENOUGH TO MAKE SKIES CLEAR EVERYWHERE ELSE. OFFSHORE FLOW
STRENGTHENS SAT AND BECOMES MORE EASTERLY. THE DRY AIR AND HIGH
PRESSURE ALOFT WILL ALLOW FOR TEMPS TO RISE TO NEAR RECORD LEVELS
FRI AND THROUGH THE WEEKEND FOR ALL AREAS. ALSO SOME WEAK OFFSHORE
WINDS CAN BE EXPECTED THROUGH AND BELOW THE PENINSULAR RANGE...SUCH
AS BANNING AND CAMPO. WEAKENING OFFSHORE FLOW SUN AND MON WILL ALLOW
THE RETURN OF A SHALLOW MARINE LAYER AND A COOLING TREND STARTING AT
THE COAST. THE STRONG UPPER HIGH WILL REMAIN THE DOMINANT FEATURE
NEXT WEEK...BUT EXTENDED MODELS SHOW VARIATIONS OF LOWER PRESSURE
PUTTING A DENT IN IT. SO NEXT WEEK WE EXPECT SOME MARINE LAYER
INFLUENCE BRINGING SEASONAL WEATHER (NOCTURNAL LOW CLOUDINESS) NEAR
THE COAST...BUT FAIR AND WARMER THAN NORMAL ELSEWHERE.
&&
.AVIATION...
091515Z...MDCRS SOUNDINGS SHOW THE MARINE LAYER DEPTH NEAR KSAN
AROUND 6000 FEET BUT THE DEPTH IS AROUND 4000 FEET NEAR KONT AND
KLAX. EXPECT THE MARINE LAYER DEPTH TO LOWER TO NEAR 3000 FEET MOST
AREAS THIS AFTERNOON. MULTIPLE LAYERS OF STRATOCU WITH BASES BETWEEN
2500 AND 4000 FEET MSL FROM THE MOUNTAINS WESTWARD TO THE COASTAL
WATERS WAS ALREADY BREAKING UP AND MOST AREAS SHOULD BECOME
SCATTERED TO LOCALLY BROKEN BY LATE MORNING. STRATUS WITH BASES
BETWEEN 2000 AND 2500 FEET MSL SHOULD REFORM ALONG THE COAST AROUND
SUNSET AND PUSH ONSHORE AND INLAND DURING THE EVENING REACHING THE
FAR INLAND VALLEY AREAS BEFORE MIDNIGHT. EXPECT THE STRATUS TO BREAK
UP BETWEEN 16Z AND 18Z ON THURSDAY.
DESERT AREAS SHOULD REMAIN MOSTLY CLEAR WITH UNRESTRICTED
VISIBILITIES THROUGH THURSDAY.
FAIRLY STRONG WEST TO NORTHWEST WINDS ACROSS THE MOUNTAINS WILL
BRING MOUNTAIN WAVE/ROTOR ACTIVITY WITH ASSOCIATED UP AND DOWN
DRAFTS AND LOW LEVEL WIND SHEAR TO THE DESERT AREAS NEAR KPSP
THROUGH THE AFTERNOON.
&&
.MARINE...COMBINED SEAS OF 8 TO 10 FEET AND WINDS BETWEEN 15 AND 30
KT WILL CONTINUE HAZARDOUS BOATING CONDITIONS FOR SMALL CRAFT. THE
WINDS AND SEAS WILL SLOWLY SUBSIDE DURING THE DAY...REMAINING THE
STRONGEST FROM 20 AND 25 KT OVER THE OUTER WATERS THROUGH THE
AFTERNOON. A SMALL CRAFT ADVISORY IS IN EFFECT THROUGH 6 PM TODAY.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 6 PM PDT THIS AFTERNOON FOR COASTAL
WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER AND OUT
30 NM-WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER
EXTENDING 30 TO 60 NM OUT INCLUDING SAN CLEMENTE ISLAND.
&&
$$
PUBLIC...MM
AVIATION/MARINE...HORTON
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
636 PM CDT THU APR 10 2008
.DISCUSSION...
257 PM CDT
ALL EYES REMAIN ON THE STORM SYSTEM TAKING AIM ON THE REGION.
MASSIVE PRECIPITATION ARC EXTENDING FROM NORTHERN OHIO ALL THE WAY
BACK TO NEBRASKA IS ALL RELATED TO STRONG WARM AIR ADVECTION OUT
AHEAD OF THE CORE OF THE SYSTEM. WITH A 40-50 LOW LEVEL JET PUMPING
UP INTO THIS SYSTEM...THERE IS AN AMPLE AMOUNT OF MOISTURE BEING
TRANSPORTED INTO THE REGION. THE MAIN LLJ AXIS SHOULD CONTINUE TO
GLIDE EASTWARD OVERNIGHT...TAKING THE INITIAL BAND OF MODERATE TO
HEAVY RAIN WITH IT. BASED ON RADAR ESTIMATES...ABOUT A QUARTER TO A
HALF INCH OF RAIN HAS ALREADY FALLEN THIS MORNING AND EARLY
AFTERNOON. WITH THE AMOUNT OF RAIN THAT HAS FALLEN OVER THE PAST
TWO DAYS...THERE REALLY IS NOT MUCH EXTRA SPACE IN THE CURRENTLY
SATURATED SOIL FOR ANY MORE RAIN. FLASH FLOOD GUIDANCE IS AT ABOUT
AN INCH AND A HALF PER HOUR BEFORE FLASH FLOODING OCCURS...WHICH IS
RELATIVELY LOW. GIVEN THE CHANCES FOR STORM REDEVELOPMENT LATER
THIS AFTERNOON AND THIS EVENING...WILL KEEP THE FLASH FLOOD WATCH
GOING FOR THE ENTIRE FORECAST AREA ALTHOUGH HEAVY RAINFALL LIKELY
WILL NOT BE AS WIDESPREAD AS PREVIOUSLY FORECAST. RIVER FORECASTS
ARE ALSO ANTICIPATED TO COME DOWN A BIT TO NOT AS MAJOR OF FLOODING
AS PREVIOUSLY FORECAST.
AS FOR THE SEVERE THREAT FOR THE REST OF THIS AFTERNOON AND
TONIGHT...IT STILL APPEARS AS THOUGH THE SLIGHT RISK ISSUED BY THE
SPC IS VALID AS THE MAIN SWATH OF LIGHT TO MODERATE RAINFALL MOVES
OUT AND THE WARM FRONT MOVES INTO THE REGION. SCATTERED CONVECTION
HAS ALREADY STARTED TO POP UP IN THE DRY SLOT ACROSS WESTERN
ILLINOIS AND THIS ACTIVITY IS ANTICIPATED TO MOVE INTO THE CWA
WITHIN THE NEXT FEW HOURS. FORECAST SOUNDINGS INDICATE THAT MOST OF
THE INSTABILITY IS RATHER ELEVATED AND NOT SURFACE BASED...SO THE
MAIN THREAT OF THE STORMS WILL LIKELY BE DAMAGING WINDS OR HAILERS.
TEMPERATURES HAVE CLIMBED TO THE LOW 60S SOUTH OF THIS WARM FRONT
WITH DEW POINTS UP AROUND 60. THE AMOUNT OF SHEAR IN PLACE IS
RATHER SUBSTANTIAL AND SHOULD BE ABLE TO OVERCOME ANY INITIAL
INSTABILITY ISSUES OUT THERE. 0-1KM BULK SHEAR ALONG THE WARM FRONT
IS ON THE ORDER OF 45 TO 55KTS WITH 0-6KM BULK SHEAR UP ABOUT 90 TO
100KTS. ANY DISCRETE STORM CELLS OR CLUSTERS MAY EVENTUALLY END UP
MERGING INTO A SQUALL LINE LATER ON TONIGHT.
AS HAS BEEN ADVERTISED THE PAST FEW DAYS..THE ENTIRE SYSTEM BECOMES
FAIRLY VERTICALLY STACKED FRIDAY THROUGH THE REST OF THE WEEKEND.
THIS WILL LEAVE CHANCES FOR RAIN SHOWERS...TRANSITIONING TO A MIX OF
RAIN AND SNOW SHOWERS AND EVENTUALLY JUST SNOW SHOWERS AND
FLURRIES. AT THIS POINT...IT DOES NOT APPEAR THAT THESE SNOW
SHOWERS WILL BE ENOUGH TO ACCUMULATE...BUT A DUSTING WOULD NOT BE
OUT OF THE QUESTION WITH SOME OF THE MORE INTENSE SHOWERS.
THE EXTENDED PERIOD WILL BEGIN OUT ON THE COLD SIDE ON MONDAY AS THE
DEEP AND SPATIALLY WIDE TROUGH SLOWLY MOVES EASTWARD TOWARD THE
ATLANTIC COAST. AS IT PROPAGATES EASTWARD...A RIDGE AXIS WILL PASS
THROUGH THE REGION BY MIDWEEK AND START ADVECTING WARMER AIR BACK
INTO THE AREA. THERE IS SOME UNCERTAINTY IN THE DETAILS OF THE LONG
TERM FORECAST...WHICH IS TYPICAL...BUT THE GENERAL TREND SEEMS TO BE
POINTING TOWARD A NICE WARM UP BACK INTO THE 60S.
HALBACH
&&
.AVIATION...
00 UTC TAFS...THE LOW IS ON THE NEBRASKA IOWA BORDER AND THE WARM
FRONT IS OVER NORTH CENTRAL ILLINOIS FROM DAVENPORT TO JUST SOUTH OF
KANKAKEE. THERE IS A LOW LEVEL JET STREAK OVER NORTH CENTRAL
ILLINOIS. THE WARM FRONT WILL MOVE INTO THROUGH 01 UTC.
THE LOW CLOUDS WILL LIFT BY THEN. THE INSTABILITY WILL BE ABOVE
4000 FT BECAUSE OF THE FRONTAL INVERSION SEEN ON THIS MORNINGS
ACARS SOUNDING. THE BASES OF THE THUNDERSTORMS MAY BE AROUND 4000
FT. WILL LEAVE THE TEMPO GROUP FOR SHOWERS BETWEEN 00 UTC AND 02
UTC. BUT THESE TAFS MAY BE AMENDED FOR THUNDERSTORMS AFTER THE FRONT
GOES NORTH OF NORTHEAST ILLINOIS. WE WILL HAVE TO WATCH THE CHANGE
IN THE STABILITY. THE DEWPOINTS ON THE SURFACE WILL INCREASE BY 02
UTC SO THE LOW LEVEL MOISTURE WILL BE PRESENT FOR THUNDERSTORMS.
ACARS SOUNDING SHOWS STRONG VEERING OF THE WIND AND AT ORD AT 22
UTC. THERE IS ENOUGH WIND SHEAR BUT MAINLY IN DIRECTION. THE
INVERSION IS DECREASING SINCE THE LAST ACARS SOUNDINGS AROUND 18
UTC. THE COLD FRONT WILL MOVE THROUGH NORTHEAST ILLINOIS BY 18 UTC
FRIDAY. THIS IS NOTED IN THE TEMPERATURE FORECAST FOR 850 AND
SURFACE FROM THE WRF_NMM FROM NCEP AND FROM THE GFS MODEL. OUR
LOCAL WRF MODEL SHOWS THE SAME. WE EXPECT ANOTHER ROUND OF
THUNDERSTORMS AHEAD OF THE FRONT AS IS APPROACHES. THIS FORECAST
FOR THUNDERSTORMS WILL BE FOR BETWEEN 08 UTC TO 12 UTC. THE LIFTED
INDEX FORECAST...WHICH IS A MEASURE OF INSTABILITY IS LOWEST AT THIS
TIME. THE LOWER THE LIFTED INDEX THE MORE UNSTABLE THE ATMOSPHERE.
COLDER AIR ASSOCIATED WITH THE COLD CONVEYOR BELT. THIS IS COLD AIR
RISINGINTO THE COMMA CLOUD BEHIND THE SURFACE LOW.
&&
.MARINE...
104 PM CDT
WE HAVE ISSUED A GALE WARNING FOR THIS EVENING ON THE SOUTHERN
HALF OF LAKE MICHIGAN AND THE NEARSHORE. THE LOW IN KANSAS HAS
INTENSIFIED AND THE RESULTING PRESSURE GRADIENT WILL BRING
A STRONGER WIND. THE GALE WARNING FOR THE NORTH HALF OF LAKE
MICHIGAN WILL STILL BE IN PLACE FOR LATER TONIGHT. THE LOW WILL
MOVE INTO SOUTHERN LAKE MICHIGAN AND THE PRESSURE GRADIENT WILL
BE ALONG THE NORTH HALF. THIS WILL GIVE STRONG WIND ON THE NORTH
HALF OF LAKE MICHIGAN. THIS LOW WILL BE SLOW TO MOVE EAST FRIDAY
AND SATURDAY. THE COMPUTER MODELS FORECAST THE LOW TO REMAIN
OVER THE SOUTHERN PORTION OF LAKE MICHIGAN THROUGH 1 AM SUNDAY.
THE WIND OVER NORTHERN LAKE MICHIGAN WILL BE AROUND 30 KNOTS
THROUGH SATURDAY. THE DIRECTION WILL BE FROM THE EAST TO
NORTHEAST.
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR ILZ003>006-008-
010>014-019>023-032-033-039.
WIND ADVISORY UNTIL 7 PM CDT FRIDAY FOR ILZ003>006-008-010>014-
019>023-032-033-039.
IN...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR INZ001-002-010-011-
019.
LM...GALE WARNING UNTIL 1 AM CDT FRIDAY FOR LMZ740>745-777-779.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
258 PM CDT THU APR 10 2008
.DISCUSSION...
257 PM CDT
ALL EYES REMAIN ON THE STORM SYSTEM TAKING AIM ON THE REGION.
MASSIVE PRECIPITATION ARC EXTENDING FROM NORTHERN OHIO ALL THE WAY
BACK TO NEBRASKA IS ALL RELATED TO STRONG WARM AIR ADVECTION OUT
AHEAD OF THE CORE OF THE SYSTEM. WITH A 40-50 LOW LEVEL JET PUMPING
UP INTO THIS SYSTEM...THERE IS AN AMPLE AMOUNT OF MOISTURE BEING
TRANSPORTED INTO THE REGION. THE MAIN LLJ AXIS SHOULD CONTINUE TO
GLIDE EASTWARD OVERNIGHT...TAKING THE INITIAL BAND OF MODERATE TO
HEAVY RAIN WITH IT. BASED ON RADAR ESTIMATES...ABOUT A QUARTER TO A
HALF INCH OF RAIN HAS ALREADY FALLEN THIS MORNING AND EARLY
AFTERNOON. WITH THE AMOUNT OF RAIN THAT HAS FALLEN OVER THE PAST
TWO DAYS...THERE REALLY IS NOT MUCH EXTRA SPACE IN THE CURRENTLY
SATURATED SOIL FOR ANY MORE RAIN. FLASH FLOOD GUIDANCE IS AT ABOUT
AN INCH AND A HALF PER HOUR BEFORE FLASH FLOODING OCCURS...WHICH IS
RELATIVELY LOW. GIVEN THE CHANCES FOR STORM REDEVELOPMENT LATER
THIS AFTERNOON AND THIS EVENING...WILL KEEP THE FLASH FLOOD WATCH
GOING FOR THE ENTIRE FORECAST AREA ALTHOUGH HEAVY RAINFALL LIKELY
WILL NOT BE AS WIDESPREAD AS PREVIOUSLY FORECAST. RIVER FORECASTS
ARE ALSO ANTICIPATED TO COME DOWN A BIT TO NOT AS MAJOR OF FLOODING
AS PREVIOUSLY FORECAST.
AS FOR THE SEVERE THREAT FOR THE REST OF THIS AFTERNOON AND
TONIGHT...IT STILL APPEARS AS THOUGH THE SLIGHT RISK ISSUED BY THE
SPC IS VALID AS THE MAIN SWATH OF LIGHT TO MODERATE RAINFALL MOVES
OUT AND THE WARM FRONT MOVES INTO THE REGION. SCATTERED CONVECTION
HAS ALREADY STARTED TO POP UP IN THE DRY SLOT ACROSS WESTERN
ILLINOIS AND THIS ACTIVITY IS ANTICIPATED TO MOVE INTO THE CWA
WITHIN THE NEXT FEW HOURS. FORECAST SOUNDINGS INDICATE THAT MOST OF
THE INSTABILITY IS RATHER ELEVATED AND NOT SURFACE BASED...SO THE
MAIN THREAT OF THE STORMS WILL LIKELY BE DAMAGING WINDS OR HAILERS.
TEMPERATURES HAVE CLIMBED TO THE LOW 60S SOUTH OF THIS WARM FRONT
WITH DEW POINTS UP AROUND 60. THE AMOUNT OF SHEAR IN PLACE IS
RATHER SUBSTANTIAL AND SHOULD BE ABLE TO OVERCOME ANY INITIAL
INSTABILITY ISSUES OUT THERE. 0-1KM BULK SHEAR ALONG THE WARM FRONT
IS ON THE ORDER OF 45 TO 55KTS WITH 0-6KM BULK SHEAR UP ABOUT 90 TO
100KTS. ANY DISCRETE STORM CELLS OR CLUSTERS MAY EVENTUALLY END UP
MERGING INTO A SQUALL LINE LATER ON TONIGHT.
AS HAS BEEN ADVERTISED THE PAST FEW DAYS..THE ENTIRE SYSTEM BECOMES
FAIRLY VERTICALLY STACKED FRIDAY THROUGH THE REST OF THE WEEKEND.
THIS WILL LEAVE CHANCES FOR RAIN SHOWERS...TRANSITIONING TO A MIX OF
RAIN AND SNOW SHOWERS AND EVENTUALLY JUST SNOW SHOWERS AND
FLURRIES. AT THIS POINT...IT DOES NOT APPEAR THAT THESE SNOW
SHOWERS WILL BE ENOUGH TO ACCUMULATE...BUT A DUSTING WOULD NOT BE
OUT OF THE QUESTION WITH SOME OF THE MORE INTENSE SHOWERS.
THE EXTENDED PERIOD WILL BEGIN OUT ON THE COLD SIDE ON MONDAY AS THE
DEEP AND SPATIALLY WIDE TROUGH SLOWLY MOVES EASTWARD TOWARD THE
ATLANTIC COAST. AS IT PROPAGATES EASTWARD...A RIDGE AXIS WILL PASS
THROUGH THE REGION BY MIDWEEK AND START ADVECTING WARMER AIR BACK
INTO THE AREA. THERE IS SOME UNCERTAINTY IN THE DETAILS OF THE LONG
TERM FORECAST...WHICH IS TYPICAL...BUT THE GENERAL TREND SEEMS TO BE
POINTING TOWARD A NICE WARM UP BACK INTO THE 60S.
HALBACH
&&
.AVIATION...
1800 UTC TAFS...THE LOW IN EASTERN KANSAS AND THE WARM FRONT IS
OVER SOUTH CENTRAL ILLINOIS. THERE IS A LOW LEVEL JET STREAK
MOVING INTO CENTRAL ILLINOIS. THE WARM FRONT WILL MOVE INTO
NORTHERN ILLINOIS BY WISCONSIN BY 00 UTC. THE LOW CLOUDS MAY LIFT
BY THEN. THERE WILL BE SOME SOLAR HEATING THIS LATE AFTERNOON.
THIS MAY INCREASE THE INSTABILITY. THE INSTABILITY WILL BE ABOVE
4000 FT BECAUSE OF THE FRONTAL INVERSION SEEN ON THIS MORNINGS
ACARS SOUNDING. THE BASES OF THE THUNDERSTORMS MAY BE AROUND 4000FT.
WILL LEAVE THE TEMPO THUNDERSTORMS IN THE TAFS FOR 23Z TO 02 UTC
FOR THE THUNDERSTORMS. WITH THE WARMER AIR AND STRONG LOW WINDS
MOVE INTO NORTHERN ILLINOIS AND NORTHWEST INDIANA WE EXPECT THE
CEILING TO LIFT TO 1000 FT BY 00 UTC AND UP TO 5000 FT BY 06 UTC.
THE WARM AIR WILL BE MOVING INTO THE REGION VERY STRONGLY BY 09
UTC. THE COLD FRONT WILL MOVE THROUGH NORTHEAST ILLINOIS BY 18 UTC
FRIDAY. THIS IS NOTED IN THE TEMPERATURE FORECAST FOR 850 AND
SURFACE FROM THE WRF_NMM FROM NCEP AND FROM THE GFS MODEL. OUR
LOCAL WRF MODEL SHOWS THE SAME. WE EXPECT ANOTHER ROUND OF
THUNDERSTORMS AHEAD OF THE FRONT AS IS APPROACHES. THIS FORECAST
WILL BE FOR 08 UTC TO 12 UTC. THE LIFTED INDEX FORECAST...WHICH IS
A MEASURE OF INSTABILITY IS LOWEST AT THIS TIME. THE LOWER THE
LIFTED INDEX THE MORE UNSTABLE THE ATMOSPHERE. COLDER AIR
ASSOCIATED WITH THE COLD CONVEYOR BELT. THIS IS COLD AIR RISING
INTO THE COMMA CLOUD BEHIND THE SURFACE LOW.
&&
.MARINE...
104 PM CDT
WE HAVE ISSUED A GALE WARNING FOR THIS EVENING ON THE SOUTHERN
HALF OF LAKE MICHIGAN AND THE NEARSHORE. THE LOW IN KANSAS HAS
INTENSIFIED AND THE RESULTING PRESSURE GRADIENT WILL BRING
A STRONGER WIND. THE GALE WARNING FOR THE NORTH HALF OF LAKE
MICHIGAN WILL STILL BE IN PLACE FOR LATER TONIGHT. THE LOW WILL
MOVE INTO SOUTHERN LAKE MICHIGAN AND THE PRESSURE GRADIENT WILL
BE ALONG THE NORTH HALF. THIS WILL GIVE STRONG WIND ON THE NORTH
HALF OF LAKE MICHIGAN. THIS LOW WILL BE SLOW TO MOVE EAST FRIDAY
AND SATURDAY. THE COMPUTER MODELS FORECAST THE LOW TO REMAIN
OVER THE SOUTHERN PORTION OF LAKE MICHIGAN THROUGH 1 AM SUNDAY.
THE WIND OVER NORTHERN LAKE MICHIGAN WILL BE AROUND 30 KNOTS
THROUGH SATURDAY. THE DIRECTION WILL BE FROM THE EAST TO
NORTHEAST.
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR ILZ003>006-008-
010>014-019>023-032-033-039.
WIND ADVISORY UNTIL 7 PM CDT FRIDAY FOR ILZ003>006-008-010>014-
019>023-032-033-039.
IN...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR INZ001-002-010-011-
019.
WIND ADVISORY UNTIL 7 PM CDT /8 PM EDT/ FRIDAY FOR INZ001-002-
010-011-019.
LM...GALE WARNING UNTIL 1 AM CDT FRIDAY FOR LMZ740>745-777-779.
SMALL CRAFT ADVISORY UNTIL 5 PM CDT THIS AFTERNOON FOR
LMZ740>745.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
235 PM CDT THU APR 10 2008
.DISCUSSION...
335 AM CDT
HEAVY RAIN AND SEVERE WEATHER POTENTIAL WILL CONTINUE TO BE THE
FOCUS OF THIS FORECAST. WILL NOT BE MAKING ANY CHANGES TONIGHT TO
GOING FLASH FLOOD WATCH HEADLINES FOR TODAY/TONIGHT.
STRONG LOW LEVEL THETA-E ADVECTION WILL CONTINUE TO SUPPORT THE
NORTHWARD EXPANSION OF RAIN ACROSS CENTRAL ILLINOIS INTO THE
FORECAST AREA EARLY THIS MORNING. INSTABILITY PROGS NOT OVERLY
IMPRESSIVE AND ANY CAPE IS QUITE ELEVATED TODAY THROUGH MID
AFTERNOON WITH SURFACE WARM FRONT ACROSS THE SOUTHERN PLAINS. SHORT
TERM NAM/RUC PROGS SEEM TO BE SUPPORTING CURRENT SITUATION WITH TWO
DISTINCT ENHANCED LOW LEVEL THETA-E GRADIENTS...THE FIRST ASSOCIATED
WITH INCREASING LOW LEVEL FLOW EARLY THIS MORNING ADVECTING MOISTURE
NORTHWARD INTO AN INITIALLY DRY AIR MASS...WITH ANOTHER LOW LEVEL
THETA-E GRADIENT FURTHER SOUTH ACROSS CENTRAL/SOUTHERN MISSOURI
ASSOCIATED WITH ELEVATED WARM FRONT. WHILE PRECIPITATION WILL BECOME
WIDESPREAD THIS MORNING...EXPECTING HEAVIER PRECIP TO OCCUR THIS
AFTERNOON ASSOCIATED WITH APPROACH OF THIS ELEVATED WARM FRONT. BY
THIS AFTERNOON MODEL FCST SOUNDINGS DO INDICATE SOME ELEVATED
INSTABILITY ON THE ORDER OF 200-400 J/KG WITH PRIMARY ELEVATED
INSTABILITY AXIS SETTING UP ACROSS WESTERN PORTIONS OF THE CWA.
SEVERE POTENTIAL DOES APPEAR TO BE LIMITED THROUGH MOST OF THE
AFTERNOON. HIGH TEMPERATURES THIS AFTERNOON WILL BE LIMITED BY
EXTENSIVE CLOUDS/PRECIP AND STIFF EASTERLY SURFACE FLOW NORTH OF THE
SURFACE WARM FRONT SHOULD KEEP TEMPS IN LOWER TO MID 40S ACROSS FAR
NORTHEAST ILLINOIS. DID GO AHEAD AND ALSO TRIM A FEW DEGREES OFF
HIGHS IN THE FAR SOUTH...WITH GENERALLY MID 50S EXPECTED.
HEAVY RAIN POTENTIAL WILL CONTINUE LATE THIS AFTERNOON INTO THIS
EVENING AS UPPER LEVEL FORCING BEGINS TO INCREASE IN RESPONSE TO
EASTWARD PROGRESSION OF STRONG UPPER LEVEL SYSTEM CURRENTLY ACROSS
THE CENTRAL ROCKIES. DISTINCT SHORT WAVE AND ASSOCIATED DRY
MID/UPPER PUNCH IS SHOWING UP NICELY ON WATER VAPOR EARLY THIS
MORNING ACROSS NORTH CENTRAL TEXAS AND THIS STRONG VORT MAX WILL BE
THE MAIN FEATURE TO MONITOR AS IT MOVES INTO THE MID MS VALLEY THIS
EVENING. IT STILL APPEARS AS THOUGH SURFACE WARM FRONT WILL REACH
FAR SOUTHERN PORTIONS OF THE CWA LATE THIS AFTERNOON TOWARD EVENING
AND REACHING INTO THE INTERSTATE 88 CORRIDOR TOWARD MIDNIGHT.
EXPECTING AN AXIS OF MODERATE INSTABILITY TO BE ASSOCIATED WITH THE
ADVANCING WARM FRONT WITH NAM/WRF MUCAPES MAXIMIZING INTO THE
1000-1500 J/KG RANGE ACROSS SOUTHEAST PORTIONS OF THE CWA THIS
EVENING AS INSTABILITY BECOMES PROGRESSIVELY MORE NEAR SFC BASED
ACROSS THE FAR SOUTH. GIVEN ABUNDANT AMOUNTS OF DEEP LAYER SHEAR AND
MODERATE INSTABILITY WILL HAVE TO MONITOR FOR POSSIBILITY OF
SUPERCELL DEVELOPMENT SOUTH OF THE WARM FRONT THIS EVENING...BUT
STILL EXPECTING PRIMARY MODE TO TRANSITION TO BOWING LINE SEGMENTS
LATE THIS EVENING AS STRONG SOUTHERN PLAINS VORT MAX LIFTS NORTHEAST
WITH STRONG AMBIENT WIND FIELD. GIVEN BEST INSTABILITY EXPECTED
MAINLY ACROSS SOUTHERN HALF OF CWA...SEVERE THREAT APPEARS TO BE
MAXIMIZED ACROSS THESE LOCATIONS. HOWEVER...ACROSS FAR NORTHERN
ILLINOIS WRF/NAM SUGGESTS SOME LOW LEVEL DEW POINT POOLING
ASSOCIATED WITH THE WARM FRONT AND INCREASING UPPER
DIFFLUENCE/DIVERGENCE. GIVEN SLIGHTLY LOWER FREEZING LEVELS ACROSS
THE NORTH AND STRONGER FORCING...PRIMARY SEVERE THREAT ACROSS THE
FAR NORTH MAY BE HAIL. PERHAPS OF GREATEST CONCERN TODAY WILL BE ON
THE POTENTIAL FOR HEAVY RAIN AND SIGNIFICANT FLOODING. WILL CONTINUE
TO FORECAST TOTAL RAINFALL AMOUNTS IN THE 1 TO 3 INCH
RANGE...ALTHOUGH LOCALIZED HIGHER AMOUNTS WILL BE POSSIBLE. IF THE
HIGHER END OF THIS FORECASTED RANGE DOES OCCUR...MODERATE/MAJOR
FLOODING WILL LIKELY OCCUR ACROSS MANY AREA RIVERS.
BY LATE TONIGHT...MAIN UPPER LEVEL SHORT WAVE IS EXPECTED TO EXIT
INTO NORTHWEST INDIANA WITH MID LEVEL DRY PUNCH SPREADING ACROSS THE
AREA. LATEST MODEL GUIDANCE CONTINUES TO SUGGEST THIS SHORT WAVE/DRY
PUNCH OUTRUNNING SFC COLD FRONT WITH THIS OCCLUDING SYSTEM...AND
MODEL
FORECAST SOUNDINGS SUGGESTS PERHAPS GREATEST INSTABILITY IN THE
09Z-15Z TIME FRAME JUST IN ADVANCE OF THE COLD FRONT. ONLY PROBLEM
WITH CONTINUED CONVECTIVE CHANCES INTO FRIDAY MORNING IS THAT
SYNOPTIC FORCING WILL BE QUITE A BIT WEAKER. HOWEVER...DID MAINTAIN
A CHANCE OF THUNDER EARLY FRIDAY MORNING ACROSS MAINLY NORTHWEST
INDIANA UNTIL FRONT CLEARS THE AREA. TEMPS WILL HAVE A NON DIURNAL
NATURE THROUGH TONIGHT...WITH RISING TEMPS TONIGHT WITH THE WARM
FRONT...AND THEN FALLING TEMPS FRIDAY AFTERNOON BEHIND THE COLD
FRONT.
UPPER LEVEL LOW WILL BE SLOW TO EXIT THE GREAT LAKES REGION INTO THE
WEEKEND WITH A CONTINUED CHANCE OF RAIN SHOWERS THROUGH SATURDAY.
PERHAPS BEST CHANCE OF PRECIP WILL BE LATER SATURDAY AS SECONDARY
TROUGH/REINFORCING COLD SHOT DROPS INTO THE AREA. WOULD NOT EVEN
COMPLETELY BE SURPRISED TO SOME LAKE EFFECT SNOW SHOWERS SATURDAY
NIGHT WITH MARGINAL THERMODYNAMIC SUPPORT. HOWEVER...EXPECTING
GENERALLY LITTLE OR NO ACCUMS AT THIS TIME. LATEST 00Z MODELS
SUGGEST PERHAPS A SLOWING TO MODERATING TREND EARLY NEXT WEEK DUE TO
PHASING OF EASTERN CANADIAN AND WESTERN GREAT LAKES UPPER LOW...BUT
BY WEDNESDAY TEMPS MAY REACH BACK WELL INTO THE 60S AS AMPLIFIED
UPPER RIDGE AXIS APPROACHES THE AREA.
MARSILI
&&
.AVIATION...
1800 UTC TAFS...THE LOW IN EASTERN KANSAS AND THE WARM FRONT IS
OVER SOUTH CENTRAL ILLINOIS. THERE IS A LOW LEVEL JET STREAK
MOVING INTO CENTRAL ILLINOIS. THE WARM FRONT WILL MOVE INTO
NORTHERN ILLINOIS BY WISCONSIN BY 00 UTC. THE LOW CLOUDS MAY LIFT
BY THEN. THERE WILL BE SOME SOLAR HEATING THIS LATE AFTERNOON.
THIS MAY INCREASE THE INSTABILITY. THE INSTABILITY WILL BE ABOVE
4000 FT BECAUSE OF THE FRONTAL INVERSION SEEN ON THIS MORNINGS
ACARS SOUNDING. THE BASES OF THE THUNDERSTORMS MAY BE AROUND 4000FT.
WILL LEAVE THE TEMPO THUNDERSTORMS IN THE TAFS FOR 23Z TO 02 UTC
FOR THE THUNDERSTORMS. WITH THE WARMER AIR AND STRONG LOW WINDS
MOVE INTO NORTHERN ILLINOIS AND NORTHWEST INDIANA WE EXPECT THE
CEILING TO LIFT TO 1000 FT BY 00 UTC AND UP TO 5000 FT BY 06 UTC.
THE WARM AIR WILL BE MOVING INTO THE REGION VERY STRONGLY BY 09
UTC. THE COLD FRONT WILL MOVE THROUGH NORTHEAST ILLINOIS BY 18 UTC
FRIDAY. THIS IS NOTED IN THE TEMPERATURE FORECAST FOR 850 AND
SURFACE FROM THE WRF_NMM FROM NCEP AND FROM THE GFS MODEL. OUR
LOCAL WRF MODEL SHOWS THE SAME. WE EXPECT ANOTHER ROUND OF
THUNDERSTORMS AHEAD OF THE FRONT AS IS APPROACHES. THIS FORECAST
WILL BE FOR 08 UTC TO 12 UTC. THE LIFTED INDEX FORECAST...WHICH IS
A MEASURE OF INSTABILITY IS LOWEST AT THIS TIME. THE LOWER THE
LIFTED INDEX THE MORE UNSTABLE THE ATMOSPHERE. COLDER AIR
ASSOCIATED WITH THE COLD CONVEYOR BELT. THIS IS COLD AIR RISING
INTO THE COMMA CLOUD BEHIND THE SURFACE LOW.
&&
.MARINE...
104 PM CDT
WE HAVE ISSUED A GALE WARNING FOR THIS EVENING ON THE SOUTHERN
HALF OF LAKE MICHIGAN AND THE NEARSHORE. THE LOW IN KANSAS HAS
INTENSIFIED AND THE RESULTING PRESSURE GRADIENT WILL BRING
A STRONGER WIND. THE GALE WARNING FOR THE NORTH HALF OF LAKE
MICHIGAN WILL STILL BE IN PLACE FOR LATER TONIGHT. THE LOW WILL
MOVE INTO SOUTHERN LAKE MICHIGAN AND THE PRESSURE GRADIENT WILL
BE ALONG THE NORTH HALF. THIS WILL GIVE STRONG WIND ON THE NORTH
HALF OF LAKE MICHIGAN. THIS LOW WILL BE SLOW TO MOVE EAST FRIDAY
AND SATURDAY. THE COMPUTER MODELS FORECAST THE LOW TO REMAIN
OVER THE SOUTHERN PORTION OF LAKE MICHIGAN THROUGH 1 AM SUNDAY.
THE WIND OVER NORTHERN LAKE MICHIGAN WILL BE AROUND 30 KNOTS
THROUGH SATURDAY. THE DIRECTION WILL BE FROM THE EAST TO
NORTHEAST.
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR ILZ003>006-008-
010>014-019>023-032-033-039.
IN...FLASH FLOOD WATCH THROUGH FRIDAY MORNING FOR INZ001-002-010-011-
019.
LM...GALE WARNING FROM 5 PM THIS AFTERNOON TO 1 AM CDT FRIDAY FOR
LMZ740>745-777-779.
SMALL CRAFT ADVISORY UNTIL 5 PM CDT THIS AFTERNOON FOR
LMZ740>745.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
632 AM CDT WED APR 9 2008
.DISCUSSION...
345 AM CDT
ACTIVE WEATHER PATTERN WILL CONTINUE THROUGH THE END OF THE WEEK
WITH MAIN FORECAST CONCERN CENTERED ON POTENTIAL VERY HEAVY RAIN
THURSDAY/THURSDAY NIGHT ALONG WITH SEVERE WEATHER
CHANCES...ESPECIALLY THURSDAY NIGHT. WILL BE ISSUING A FLASH FLOOD
WATCH FOR ALL OF THE FORECAST AREA FOR THURSDAY/THURSDAY NIGHT.
IN THE MEANTIME...A FAIRLY QUIET DAY IS IN STORE TODAY AS THE MAIN
UPPER LEVEL LOW CONTINUES TO LIFT NORTHEAST THROUGH THE NORTHERN
GREAT LAKES. SATELLITE IMAGERY STILL INDICATING A RATHER EXPANSIVE
AREA OF LOW CLOUDS BENEATH A STRENGTHENING SUBSIDENCE INVERSION
BEHIND THIS UPPER LEVEL SYSTEM. HOWEVER...ALREADY BEGINNING TO SEE
SOME HOLES IN THE LOW CLOUDS TOWARD QUINCY AND GIVEN STRENGTHENING
SUBSIDENCE AND A PROGRESSIVELY MORE SHALLOW NATURE TO THE
LINGERING LOW LEVEL MOISTURE...SHOULD SEE LOW CLOUDS BEGINNING TO
SCATTER BY MID TO LATE MORNING WITH OTHERWISE MAINLY JUST SOME
INCREASING CIRRUS THIS AFTERNOON. GUSTY WEST NORTHWEST WINDS TO 30
MPH EARLY THIS MORNING WILL SUBSIDE RATHER STEADILY THROUGH THE DAY AS A
RIDGE OF HIGH PRESSURE SETTLES INTO THE UPPER/MID MS RIVER VALLEY.
FOR MAX TEMPS TODAY...GENERALLY MIXED DOWN NAM 925 HPA THERMAL
PROGS WHICH WOULD GIVE HIGHS RANGING FROM UPPER 40S TOWARD THE RFD
AREA...TO THE UPPER 50S FAR SOUTH.
LULL IN THE WEATHER WILL BE SHORT LIVED AS WATER VAPOR IMAGERY
ALREADY HIGHLIGHTING NEXT UPPER LEVEL TROUGH TO AFFECT THE AREA
CURRENTLY ACROSS WESTERN CONUS. AS THIS UPPER LEVEL TROUGH DIGS INTO
THE FOUR CORNERS REGION BY THIS EVENING...A STRONG LOW LEVEL JET
WILL DEVELOP ACROSS THE SOUTHERN PLAINS. ALTHOUGH LOW/MID LEVELS
WILL HAVE DRIED OUT QUITE A BIT TODAY...THIS STRENGTHENING LOW LEVEL
JET WILL PROVIDE SIGNIFICANT MOISTURE TRANSPORT BACK ACROSS SOUTHERN
PORTIONS OF THE FORECAST AREA TOWARD MORNING WITH GFS/NAM PROGS
INDICATE 850 HPA WINDS INCREASING TO 40 TO 50 KNOTS BY MORNING. SHOULD
SEE RAIN MOVE BACK INTO FAR SOUTHERN PORTIONS OF THE FORECAST AREA
AFTER 09Z TONIGHT WITH RAIN OVERSPREADING REMAINDER OF THE
FORECAST AREA THURSDAY MORNING. AS EAST WINDS STRENGTHEN NORTH OF
THE LOW LEVEL WARM FRONT DURING THE DAY THURSDAY...LOW LEVEL
MOISTURE CONVERGENCE WILL ALSO BECOME ENHANCED AND WILL INCLUDE
MENTION OF LOCALLY HEAVY RAIN DURING THE DAY THURSDAY WITH PWATS
INCREASING BETWEEN 1 AND 1.5 INCHES. ELEVATED INSTABILITY NOT
LOOKING TO BE OVERLY IMPRESSIVE DURING THE DAY THURSDAY BUT GIVEN
STRENGTH OF ISENTROPIC LIFT/LOW LEVEL MOISTURE CONVERGENCE WILL
KEEP MENTION OF SCT THUNDER THROUGH THE DAY.
PRIMARY SEVERE THREAT IS EXPECTED DURING VERY LATE AFTERNOON AND
INTO THE EVENING HOURS ON THURSDAY AS STRONG UPPER LEVEL VORT
MAX/SPEED MAX EJECTS NORTHEAST FROM MAIN UPPER LOW ACROSS THE
CENTRAL PLAINS. 00Z GFS INDICATES A 100-110 KNOT SPEED MAX AT 500
HPA PROVIDING VERY STRONG DEEP LAYER SHEAR. SURFACE WARM FRONT IS
EXPECTED TO TRACK NORTHWARD ACROSS NORTHEAST ILLINOIS THURSDAY
EVENING PROVIDING BETTER INSTABILITY...ALTHOUGH FORECAST SOUNDINGS
NOT INDICATING A GREAT POTENTIAL OF REALIZING SURFACE BASED
INSTABILITY. MAIN THREATS APPEAR TO BE HAIL AND DAMAGING WINDS
THURSDAY NIGHT. BIGGEST CONCERN THURSDAY NIGHT WILL LIKELY BE ON
POTENTIAL FOR ANOTHER ROUND OF HEAVY RAINFALL WITH THE
AFOREMENTIONED VORT MAX LIFTING INTO THE AREA. A LOOK AT CORFIDI
VECTORS ALSO SUGGESTS BACKBUILDING POTENTIAL THURSDAY EVENING
GIVEN LOW LEVEL JET MAGNITUDE OF 50 TO 60 KNOTS. GIVEN RECENT RAIN
ACROSS THE AREA LAST EVENING...AND AT LEAST TWO ROUNDS OF
POTENTIALLY HEAVY RAIN THURSDAY/THURSDAY NIGHT WITH A POTENTIAL OF
1 TO 3 INCHES OF ADDITIONAL RAINFALL WITH LOCALLY HIGHER
AMOUNTS...WILL GO AHEAD AND ISSUE A FLASH FLOOD WATCH FOR ALL OF
THE FORECAST AREA FROM 12Z THURSDAY TO 12Z FRIDAY. RAINFALL
AMOUNTS OF THIS MAGNITUDE WOULD LIKELY SEND SEVERAL RIVER FORECAST
POINTS INTO MODERATE/MAJOR FLOODING ALSO.
THE CENTRAL PLAINS UPPER LOW WILL SLOWLY LIFT INTO THE UPPER MS
VALLEY FRIDAY WITH CONTINUED SHOWERY WEATHER...ALTHOUGH ADDITIONAL
RAIN AMOUNTS ON FRIDAY WILL BE MEAGER COMPARED TO THURSDAY. HAVE NOT
MADE ANY SIGNIFICANT CHANGES TO THE REMAINDER OF THE FORECAST
TONIGHT...WITH CURRENT FORECAST SEEMING INLINE WITH 00Z PROGS.
WEEKEND WILL BE COOL WITH CONTINUED CHANCE OF RAIN SHOWERS OR
PERHAPS A FEW SNOW SHOWERS ACROSS NORTH CENTRAL ILLINOIS ON SATURDAY
WITH TEMPS ONLY REACHING INTO THE LOWER TO MID 40S. CONDITIONS
SHOULD DRY OUT FOR SUNDAY AS UPPER RIDGE AXIS ACROSS WESTERN US BUILDS
EASTWARD WITH MODERATING TEMPS EARLY NEXT WEEK.
MARSILI
&&
.AVIATION...
632 AM CDT
FOR THE 12Z TAFS...MAIN CONCERN THIS MORNING IS CEILINGS.
GOES 11-3.9 MICRON IR IMAGERY CONTINUES TO SHOW LARGE AREA OF LOW
STRATUS ACROSS UPPER MIDWEST THIS MORNING...THOUGH CONTINUED DRY
LOW LEVEL ADVECTION HAS ALLOWED CEILINGS TO GRADUALLY RISE FROM
IFR TO MVFR ACROSS TERMINALS LAST FEW HOURS. VARIOUS ACARS
ASCENT/DESCENT SOUNDINGS FROM KRFD AND KORD SUGGEST THIS CLOUD
LAYER IS LIKELY FAIRLY SHALLOW...WITH BASE OF INVERSION NOTED
BETWEEN 1500-2000 FEET...AND 06Z WRF FORECAST SOUNDINGS ALSO
SUGGEST MOIST LAYER RATHER SHALLOW. THUS DESPITE LARGE AREAL
COVERAGE...EXPECT CONTINUED IMPROVEMENT AND EVENTUAL SCATTERING
OF LOW CLOUD LAYER BY LATE MORNING. REMAINDER OF THE DAY AND THIS
EVENING EXPECTED TO BE VFR AS SUBSIDENCE AND DRYING CONTINUE AS
UPPER/SURFACE RIDGE BUILD ACROSS TERMINALS. UPPER PATTERN REMAINS
VERY PROGRESSIVE HOWEVER...AND NEXT MAJOR WEATHER SYSTEM WILL
BEGIN TO AFFECT TERMINALS BY 12Z THURSDAY. DEEPENING UPPER TROUGH
ACROSS WESTERN CONUS TO INDUCE STRONG MOISTURE RETURN THROUGH THE
MISSISSIPPI VALLEY ON 40-50 KNOT 850 HPA JET WHICH SPREADS INTO
ILLINOIS TOWARD MORNING. MODEL TIME SECTIONS INDICATE GRADUALLY
LOWERING VFR MID DECK ESPECIALLY AFTER 06Z. 06Z WRF INDICATES 850
HPA MOISTURE CONVERGENCE MAXIMIZING ACROSS NORTHERN ILLINOIS
TOWARD 12Z SUGGESTING ELEVATED BAND OF SHOWERS LIKELY APPROACHING
TERMINALS FROM THE SOUTH BY END OF TAF PERIOD. HAVE INDICATED VCSH
LAST COUPLE OF HOURS TO INDICATE THIS TREND.
AS FOR WINDS...GRADIENT BEGINNING TO RELAX THIS MORNING AS LOW
PRESSURE CONTINUES TO PULL AWAY TO THE NORTH ACROSS NORTHERN LOWER
MICHIGAN. STILL SOME GUSTS INTO THE 15-20 KNOT RANGE IN ONE MINUTE
ASOS OBS AT BOTH KORD AND KMDW...THOUGH EXPECT AS GRADIENT
CONTINUES TO WEAKEN THAT GUSTINESS WILL SUBSIDE NEXT FEW HOURS.
DIRECTION EXPECTED TO BE GENERALLY WEST/NORTHWEST THROUGH THE
MORNING THOUGH WILL EVENTUALLY VEER AROUND TO NORTHEAST LESS THAN
10 KNOTS LATER THIS AFTERNOON AS SURFACE RIDGE MOVES ACROSS
TERMINALS. DEEPENING SURFACE LOW OVER SOUTHERN PLAINS AND PRESSURE
FALLS INTO ILLINOIS LATE TONIGHT WILL RESULT IN EAST/NORTHEAST
WINDS INCREASING AGAIN...WITH GUSTS NEAR 20 KNOTS LIKELY BY 12Z.
RATZER
&&
.MARINE...
308 AM CDT
LOW PRESSURE OVER CENTRAL LAKE MICHIGAN EARLY THIS MORNING WILL
CONTINUE TO MOVE NORTHEAST ACROSS SOUTHERN ONTARIO AND INTO
SOUTHWEST QUEBEC BY THIS EVENING. WEAK HIGH PRESSURE RIDGING
OVER THE CENTRAL PLAINS WILL MOVE ACROSS THE LAKE TONIGHT. DEEP
LOW PRESSURE INCHES WILL THEN DEVELOP OVER THE SOUTHERN PLAINS BY
EARLY THURSDAY...AND WILL LIFT NORTHEAST INTO THE MID MISSISSIPPI
VALLEY BY FRIDAY MORNING. TIGHTENING OF THE SURFACE PRESSURE
GRADIENT AS THIS LOW APPROACHES WILL RESULT IN INCREASING EASTERLY
WINDS THURSDAY NIGHT INTO FRIDAY...WITH GALE FORCE WINDS LIKELY
ESPECIALLY ON THE NORTHERN PART OF LAKE MICHIGAN. THE LOW WILL
THEN FILL SLIGHTLY TO 29.4 INCHES AS IT DRIFTS EAST ACROSS THE
GREAT LAKES FRIDAY AND FRIDAY NIGHT...MOVING EAST TO THE EASTERN
LAKES ON SATURDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH FROM THURSDAY MORNING THROUGH FRIDAY MORNING
FOR ILZ003>006-008-010>014-019>023-032-033-039.
IN...FLASH FLOOD WATCH FROM THURSDAY MORNING THROUGH FRIDAY MORNING
FOR INZ001-002-010-011-019.
LM...SMALL CRAFT ADVISORY UNTIL 7 AM CDT THIS MORNING FOR LMZ740>745.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1041 PM EDT THU APR 10 2008
.MESOSCALE UPDATE...
OVER THE PAST HOUR...CONVECTION OVER WESTERN KY HAS BEEN RATHER
DISORGANIZED WITH SOME WARNINGS HAVING BEEN ISSUED WITH SOME REPORTS
OF WIND AND HAIL. FIRST LINE OF CONVECTION NOW BEGINNING TO ENTER
OUR FAR WESTERN AREA. HOWEVER...THIS LINE IS WEAKENING RAPIDLY.
THIS IS NOT SUPRISING GIVEN THE 00Z BNA SOUNDING AND RECENT ACARS
SOUNDINGS OUT OF KSDF SHOWING RATHER DRY LOW LEVELS AND LARGE CAPS
AROUND 750 HPA.
TWO DISCTINCT AREAS OF CONVECTION APPEAR TO BE FORMING WITH THE
FIRST ACROSS SOUTHERN ILLNIOIS WHICH WILL AFFECT OUR SOUTHERN
INDIANA COUNTIES LATER THIS EVENING. LAPS AND MSAS ANALYSIS SHOWS
GOOD MOISTURE POOLING ACROSS WESTERN TN...AND LIKEWISE...VERY STRONG
STORMS NOW DEVELOPING ACROSS NORTHWEST TN. 11/00Z 4KM SPC WRF
FORECASTED THIS STORM EVOLUTION QUITE WELL AND SHOVES IT EAST ACROSS
NORTHERN TN AND SOUTHERN KY OVERNIGHT. CURRENT THINKING IS THAT
STRONG SFC CONFLUENCE ACROSS WEST TN COMBINED WITH DEVELOPING
LOW-LEVEL JET SHOULD KEEP STORMS GOING FOR THE NEXT FEW HOURS.
STILL QUESTIONABLE HOW FAR THIS FORCING WILL GO EAST AND TRY TO
ERODE THE CAP.
BASED ON CURRENT TRAJECTORIES...SHOWERS AND STORMS ARE NOW IN OUR NW
CWA...AND THEY SHOULD BEGIN TO REACH THE I-65 CORRIDOR BY 100 AM EDT.
.EVENING UPDATE...
UPDATED FORECAST TO ACCOUNT FOR ARRIVAL TIME OF BROKEN LINE OF
STORMS NOW IN WESTERN KENTUCKY. FORECAST SOUNDINGS SHOW PLENTY OF
LOW LEVEL HELICITY...BUT RELATIVELY WEAK MID-LEVEL LAPSE RATES AND
MARGINAL INSTABILITY. IN ADDITION...LOW LEVEL MOISTURE IS SOMEWHAT
LACKING FOR WIDESPREAD SEVERE WX. WITH STRONG LOW TO MID LEVEL
WINDS...ISOLATED DAMAGING WINDS WILL BE THE MOST LIKELY SEVERE
THREAT.
BROKEN LINE OF STORMS WILL MOVE INTO SOUTHERN INDIANA AND INTO WEST
CENTRAL KENTUCKY PRIOR TO MIDNIGHT...AND INTO THE BLUEGRASS REGION
DURING THE EARLY MORNING HOURS. AFTER THIS INITIAL LINE OF STORMS
PASS...EXPECT A NUMBER OF DRY HOURS THIS MORNING BEFORE A COLD FRONT
MOVES ACROSS THE AREA THIS AFTERNOON.
.SHORT TERM (TONIGHT AND FRIDAY)...
...SEVERE WEATHER POSSIBLE LATE TONIGHT...ESPECIALLY OVER SRN
INDIANA AND WEST CENTRAL KENTUCKY...WEST OF INTERSTATE 65...
UPR LOW OVER KANSAS STRENGTHENS ON ITS NEWD TRACK INTO IOWA BY 12Z
FRI AND MAINTAINS ITS INTENSITY INTO THE WESTERN GREAT LAKES FRI.
SHRTWV TROF ON E/SE EDGE OF CLOSED CIRCULATION...FORECAST TO
STRENGTHEN THRU 06Z TNGT AS IT APPROACHES STL AND THEN WEAKEN
CONSIDERABLY BY 12Z AS IT APPROACHES SOUTHWEST INDIANA. VORTICITY IS
THEN FORECAST TO SHEAR ENE INTO SRN INDIANA/OHIO FRI. BASED ON
THIS...MAXIMUM DIFFERENTIAL POSITIVE VORTICITY ADVECTION WOULD OCCUR
ACRS ERN MO/WRN IL EARLY TNGT WITH A LINEAR MCS LIKELY AHEAD OF
IT...MOVING INTO OUR WRN MOST CWA BEFORE MIDNIGHT TNGT. THIS MCS
SHOWN BY THE MODELS WOULD BE AHEAD OF/ON PREFNTL TROF AS ASSOCIATED
SFC LO REACHES IOWA WITH A TRAILING CDFNT SOUTHWARD INTO CENTRAL MO.
THE COMBINATION OF MAX FORCING...AVAILABLE CAPE AND MAX WIND SHEAR
POINTS AT OUR SWRN MOST INDIANA COUNTIES AS MOST PRONE TO SVR STMS
LATE THIS EVE WITH JUST A BIT LESSER THREAT SWD INTO WCNTRL AND
SCNTRL KY...WEST OF I-65. SVR THREAT SHUD THEN WANE OVERNIGHT AS MCS
MOVES FARTHER AWAY FROM BEST FORCING/DYNAMICS/INSTABILITY. LATEST
DAY 1 OUTLOOK HAS BACKED OFF THE MODERATE RISK FOR OUR WRN CWA AND
REPLACED WITH SLGT...WITH OUR FAR ERN COUNTIES JUST IN GENERAL
THUNDER.
NAM IS MORE AGGRESSIVE WITH DEVELOPING ANOTHER LINEAR MCS INTO OUR
CWA BY EARLY AFTN FRI...GFS LESS SO. THE ERN HALF OF OUR FA IN A
SLGT RISK...THOUGH IN A MINIMAL AREA COMPARED WITH THE BETTER
DYNAMICS TO THE NORTH AND BETTER INSTAB TO THE SOUTH. GRADIENT WINDS
FRI MAY BE A BIGGER THREAT WITH PREFNTL GUSTS POSSIBLY EXCEEDING 40
MPH...PONDERED A WIND ADVISORY WITH THIS ISSUANCE...BUT MAIN WINDS
SHUD HOLD OFF TIL LATE MORNING/AFTN FRI...SO WILL WAIT ON ANOTHER
MODEL RUN FOR SIMILAR MOS TRENDS SHOWING SUSTAINED WINDS IN THE MID
TO UPPER 20 MPH RANGE. ANOTHER CONCERN IS EXCESSIVE RAINFALL...LATE
TNGT...EARLY FRI. IF THIS OCCURS...MOST LIKELY ACRS SRN INDIANA...
IT IS OVER AN AREA WHICH DID NOT RECEIVE THE RAINS THAT CENTRAL KY
GOT ABOUT 10 DAYS AGO AND THE GROUND CAN HOLD MUCH MORE WATER NOW
WITH NEW/GROWING VEGETATION ABSORBING IT. NO FFA ATTM.
.LONG TERM (FRIDAY NIGHT THROUGH THURSDAY)...
FRIDAY NIGHT THROUGH MONDAY...
MAIN CONCERN FOR THE LONGER TERM WITH SHOWERS OCCURRING IN THE
MOISTURE WRAPPING AROUND THE UPPER LEVEL LOW THAT WILL SPREAD ACROSS
SOUTH CENTRAL INDIANA AND CENTRAL KENTUCKY SATURDAY INTO MONDAY.
AFTER THE COLD FRONT PUSHES THROUGH LATE FRIDAY AFTERNOON...COOLER
AIR WILL BEGIN TO FLOW INTO THE LOWER OHIO VALLEY. IN ADDITION DRIER
AIR WILL BRING A TEMPORARY END TO THE SHOWERS FOR PARTS OF FRIDAY
NIGHT. EXPECT THE DRY SLOT TO REMAIN OVER MUCH OF THE AREA FRIDAY
NIGHT AND INTO THE FIRST PART OF SATURDAY MORNING. HOWEVER AS THE
UPPER TROUGH ROTATES SOUTH TOWARD THE OHIO RIVER SATURDAY
MORNING...CLOUDS WILL INCREASE AND SCATTERED SHOWERS WILL ONCE AGAIN
DEVELOP DURING THE AFTERNOON AND EVENING HOURS. THE SHOWERS WILL
DECREASE SOME DURING THE OVERNIGHT HOURS BUT A SECOND TROUGH WILL
TRIGGER AND INCREASE IN SHOWERS ON SUNDAY. THIS UPPER LEVEL SYSTEM
WILL SLOWLY EXIT THE REGION ON MONDAY.
TEMPERATURES ON SATURDAY WILL BE NOTICEABLY COOLER THAN FRIDAY/S
MILD READINGS...WITH HIGHS ON SATURDAY ONLY IN THE LOWER AND MID
50S. BRISK NORTHWEST WINDS OF 15 TO 25 MPH WILL MAKE THE AIR FEEL
EVEN COLDER.
HIGH TEMPERATURES WILL HOVER AROUND 50 DEGREES AGAIN SUNDAY AND
MONDAY WITH MORNING LOWS IN THE MID 30S.
MONDAY NIGHT THROUGH THURSDAY...
HIGH PRESSURE WILL BUILD INTO THE AREA MONDAY NIGHT AND TUESDAY AND
WILL GRADUALLY TRACK EAST ACROSS CENTRAL KENTUCKY AND SOUTH CENTRAL
INDIANA. THE HIGH WILL SETTLE OFF THE GEORGIA AND CAROLINA COAST ON
THURSDAY AND THIS SHOULD KEEP THE LOWER OHIO VALLEY DRY FOR SEVERAL
DAYS. TEMPERATURES WILL BE COOL THE BEGINNING OF THE WEEK WITH
TEMPERATURES WARMING BACK INTO THE MID 60S TO LOWER 70S BY
THURSDAY.
&&
.AVIATION (00Z TAFS)...
SKIES WILL CONTINUE PARTLY CLOUDY WITH MID LEVEL CU AND VFR CIGS
UNTIL SHORTLY BEFORE A LINE OF STORMS MOVES ACROSS EACH TAF SITE.
SURFACE WINDS WILL CONTINUE OUT OF THE SOUTH AT 10 TO 20 MPH
OVERNIGHT...BUT STRONGER WINDS AT 2000 FEET WILL REQUIRE CONTINUED
LOW LEVEL WIND SHEAR OVERNIGHT.
THE ESTIMATED TIMING OF THE LINE OF STORMS IS 04Z TO 08Z AT SDF AND
BWG...AND 07Z TO 11Z AT LEX. DURING THE PASSAGE OF THESE
STORMS...WIND GUSTS UP TO 45 MPH AND MVFR CIGS AND VISIBILITIES
SHOULD BE EXPECTED.
ONCE THESE STORMS PASS...GUSTY SOUTH WINDS WILL CONTINUE...AND MVFR
CIGS MAY IMPROVE TO PARTLY CLOUDY SKIES DURING THE MORNING HOURS.
A COLD FRONT WILL MOVE SOUTHEAST OF THE OHIO RIVER DURING FRIDAY
AFTERNOON. ADDITIONAL STORMS MAY DEVELOP ALONG THE FRONT. SHOULD
THESE DEVELOP...STRONG WINDS ARE POSSIBLE WITH THESE STORMS AS WELL.
WINDS WILL ABRUPTLY SHIFT TO THE NORTHWEST BEHIND THIS FRONT.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
MESOSCALE....MJ
SHORT TERM...JSD
LONG TERM....MBS
AVIATION.....JSD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1055 PM EDT THU APR 10 2008
.UPDATE...
UPSTREAM RADAR A BIT MESSY SIDE WITH CLUSTERS OF INTENSE CONVECTION
FM NORTHEAST WI INTO SCNTRL WI AND INTO FAR ERN IA/IL. SO FAR...DRY
AIR SEEN ON AFTN TAMDAR SOUNDINGS IS KEEPING PCPN OVR WI BUT THERE
ARE RECENT SIGNS OF PCPN HITTING GROUND WITH MNM AND IWD OBS SHOWING
VSBY OF 8SM. REPORT NEAR IWD EARLIER IN EVENING TURNED UP A COATING
OF SNOW...BUT WITH SFC TEMPS ABOVE FREEZING...ROADS WERE STILL WET.
STRENGTH OF LARGE SCALE SYSTEM IMPRESSIVE. 00Z RAOBS INDICATED WARM
AIR FEEDING INTO IL WITH H85 TEMP OF +15C AT LINCOLN IL WHILE H85
TEMP WAS +2C AT GRB. WARM AIR WAS INITIALIZED WELL BY 00Z NAM. H85
TEMP PROGS FM NAM INDICATE WARM AIR ALOFT INTO SCNTRL AND EASTERN
ZONES BY 12Z AND NOT GIVING GROUND UNTIL LATE FRIDAY. TWEAKED GRIDS
TO REMOVE SNOW/SLEET RIGHT ALONG LK MICHIGAN AND JUST GO WITH RAIN.
FARTHER INTO THE COLD AIR...EXPECT PERIODS OF HEAVY SNOW 06Z THROUGH
15Z FRI. ACTUALLY...SNOW RATES LATE TONIGHT (AFT 09Z) COULD BE VERY
INTENSE WITH SHARP RIBBON OF H8 FRONTOGENESIS/ELEVATED INSTABILITY
(H7-H5 LAPSE RATES ABOVE 7C/KM) AND UPR DIVERGENCE ALL COMING
TOGETHER AS UPR DIFFLUENCE SWEEPS ACROSS UPR MI JUST AHEAD OF
EMERGING 150KT H3 JET/100KT H5 SPEED MAX LIFTING INTO ECNTRL WI/NW
LWR MI. IMPRESSIVE DRY SLOT NOSING INTO CNTRL IL SHOULD ARRIVE IN
SOME FASHION LATE FRI MORNING...AND LATEST QPF FM NAM/HPC DEPICT
THIS WELL. BASICALLY...OVERALL GIST OF GOING FORECAST DID NOT
CHANGE. DID TWEAK POPS/WX/QPF/SNOW AMOUNTS TO CONFINE THE HEAVIEST
SNOW IN THE 06Z-15Z TIME FRAME.
UPDATED/PUBLISHED GRIDS AND WSW STATEMENT ALREADY OUT. TARDY ZFPMQT
UPDATE IS COMING SHORTLY.
&&
DISCUSSION....
SHORT TERM...UP TO 00Z FRI...
UPPER AIR PATTERN CONSISTS OF A 500 MB CLOSED LOW ACROSS SW KS WITH
A STRONG 500 MB TROUGH ACROSS THE WESTERN HIGH PLAINS AND SHORTWAVE
RIDGING ACROSS THE UPPER GREAT LAKES. NAM TAKES THE 500 MB LOW
NORTHEAST TOWARDS THE AREA AND UP INTO THE UPPER GREAT LAKES REGION
ON FRI AND SAT WITH VERY SLOW MOVEMENT TO THE EAST.
LOOKING AT MODEL SOUNDINGS FROM THE GFS...KCMX...KSAW...KERY AND
KIWD ALL SHOW TEMPERATURES THROUGHOUT THE PROFILE REMAINING AT OR
BELOW FREEZING...SO ACCORDING TO THE GFS...PCPN TYPE SHOULD STAY ALL
SNOW. KISQ AND KESC SHOWS A WARM LAYER ALOFT AT 18Z FRI AROUND 800
MB OF 3C AND TEMPERATURES REMAINING ABOVE FREEZING FROM ABOUT 760 MB
TO 860 MB WITH THE SOUNDING REMAINING BELOW ZERO OTHERWISE. KMNM HAS
AN ELEVATED LAYER ABOVE FREEZING 06Z TONIGHT FROM 700 MB TO 850 MB
WITH WARMEST TEMPERATURES AROUND 3C AND THIS ELEVATED LAYER REMAINS
THROUGH 18Z FRI. KIMT HAS ELEVATED WARM LAYER AS WELL AT 18Z OF
2C...OTHERWISE THE SOUNDING REMAINS BELOW FREEZING THE WHOLE TIME.
IRON RIVER HAS ELEVATED LAYER OF 1C AT 18Z BUT VERY LITTLE LAYER OF
ABOUT 50 MB THICK FROM 750MB TO 800 MB. NAM FORECAST SOUNDINGS
SIMILAR TO THE GFS WITH THE WARM LAYER ALOFT AND WHO WOULD SEE SNOW
AND WHO WOULD SEE MIXED PCPN. WILL GO WITH MIXED PCPN FROM SOUTH OF
A LINE FROM IRON RIVER TO GERMFASK AS A FIRST GUESS. NORTH OF THAT
LINE WILL STAY ALL SNOW. FOLLOWED THIS REASONING FOR SNOW AMOUNTS
WITH DIFFERENT RATIOS USED WITH SLEET...RAIN AND SNOW MIXED IN WHICH
WILL LOWER LOWER THE SNOWFALL TOTALS. HAD A HARD TIME TRYING TO
REFLECT WHAT WAS GOING ON WITH THE MIXED PCPN INTO THE SNOW FORECAST
AND COULD HAVE SPEND ANOTHER COUPLE HOURS TRYING TO FINE TUNE
GRIDS...BUT THEN WOULD NOT HAVE TIME TO ISSUE PRODUCTS OR FORECAST
OTHER GRIDS. SNOW AMOUNTS...NOT CONFIDENT ENOUGH THAT I GOT THESE
RIGHT BUT BEST GUESS FOR STORM TOTALS IS UP TO TWO FEET...ESPECIALLY
IN THE HIGHER TERRAIN IN THE HURON MOUNTAINS AND UPSLOPE AREAS OF
MARQUETTE COUNTY WITH LESSER AMOUNTS NEAR THE SHORELINES AND THE
SOUTH AND EAST.
ONE MAJOR CHANGE I DID IS STARTED THE PCPN OFF AS SNOW TONIGHT AS
SOUNDINGS SHOWED AS SUCH WITH EVAPORATIVE COOLING TAKING PLACE WITH
SOME DRY AIR. THIS IS WHAT HAPPENED AT KGRB WHEN PCPN STARTED THIS
AFTERNOON...STARTED OFF BRIEFLY AS RAIN AND THEN QUICKLY CHANGED
OVER TO SNOW. WITH EALIER SNOW...SNOW AMOUNTS WILL BE UP. BLIZZARD
CONDITIONS WITH THE WINDS WILL BE A PROBLEM FOR LATE TONIGHT AND
FRI. DID NOT MAKE TOO MANY MAJOR CHANGES TO THE GOING FORECAST.
.LONG TERM...00Z SAT - 00Z MON
THE LOW WILL LIFT NORTHEAST INTO CENTRAL IOWA DRAGGING THE COLD
FRONT INTO MIDDLE MISSISSIPPI RIVER VALLEY FRIDAY NIGHT. ISENTROPIC
ASCENT AHEAD OF THE FRONT WILL CONTINUE TO DESTABILIZE THE LOW
LEVELS. USING A BLEND OF ECMWF AND GFS STILL SHOWS A .6-.7 INCH QPF
ACROSS THE AREA FRIDAY NIGHT. BUFKIT SUGGESTING A 8 TO 1 RATIO OVER
CENTRAL U.P. WITH A LITTLE HIGHER RATIO OVER THE WEST AND LESS OVER
THE EAST. LOOKING AT THE TEMPERATURE PROFILES...THIS SEEMS
REASONABLE FOR SNOW TOTALS. THIS WILL GIVE US TOTALS OF UP TO 6
INCHES OVER THE HIGHER TERRAIN OF NORTH CENTRAL U.P. AND 2 TO 3
INCHES ELSEWHERE DURING THIS PERIOD. THIS APPEARS TO BE IN LINE WITH
THE HPC GUIDANCE AS WELL.
THE LOW WILL DIG INTO SOUTHWEST LOWER MICHIGAN AS THE LONGWAVE
TROUGH SWEEPS INTO SOUTHEAST ONTARIO ON SATURDAY. Q-VECTOR ENERGY
WILL WEAKEN OVER THE AREA. AS THE LOW SWEEPS SOUTHEAST...DRIER AIR
WILL START TO INVADE THE FORECAST AREA FROM THE NORTHWEST
DIMINISHING THE CHANCES OF SNOW. GFS/ECMWF CONTINUE TO SHOW QPF OVER
THE AREA ON THE ORDER OF .4 TO .5 INCHES OVER U.P. KEEPING WITH THE
SAME RATIO...WILL GIVE SNOW TOTALS ON 1 TO 3 INCHES OVER THE AREA
WITH THE HEAVIEST OVER THE NORTHERN U.P.
THE LONGWAVE TROUGH WILL CONTINUE TO DOMINATE THE GREAT LAKES REGION
SATURDAY NIGHT INTO SUNDAY. A WEAK SHORTWAVE...WITH INCREASED
Q-VECTOR CONVERGENCE...SLIDING THROUGH THE TROUGH WILL ENTER INTO
THE FORECAST AREA. THE SURFACE RIDGE WILL SHIFT INTO NORTHERN
ONTARIO...THE UPPER MISSISSIPPI RIVER VALLEY AND THE FORECAST AREA.
THE AIR MASS WILL BE LITTLE DRY. THUS WILL KEEP A CHANCE OF SNOW
WILL CONTINUE OVER THE NORTHERN U.P. AS WINDS WILL REMAIN OUT OF THE
NORTH DRAWING SOME MOISTURE FROM THE LAKE.
THE CLOSED LOW OVER SOUTHERN QUEBEC WILL SLIDE EAST INTO THE
CANADIAN MARITIME SUNDAY NIGHT AND MONDAY. THE ACCOMPANYING LONGWAVE
TROUGH WILL EDGE INTO THE LOWER GREAT LAKES. A WEAK SHORTWAVE WILL
SWEEP THROUGH THE FORECAST AREA. THE RIDGE WILL MOVE INTO NORTHERN
ONTARIO AS ANOTHER LONGWAVE TROUGH EDGES INTO THE PACIFIC NORTHWEST.
THE SURFACE RIDGE WILL THEN NAVIGATE OVER THE UPPER GREAT LAKES. THE
LOWER GREAT LAKES LONGWAVE TROUGH WILL REACH THE EAST COAST ON
TUESDAY...WHILE WEST COAST TROUGH WANDERS INTO SOUTH CENTRAL CANADA
AND THE RIDGE WILL MOVE ACROSS UPPER MICHIGAN. THE SURFACE RIDGE
WILL REACH EASTERN CONUS AS A SURFACE LOW AND ACCOMPANYING COLD
FRONT TRACKS THROUGH THE NORTHERN PLAINS. ISENTROPIC ASCENT AHEAD OF
THE LOW WILL GENERATE A SOME RAIN SHOWERS OVER WESTERN LAKE SUPERIOR
LATE ON TUESDAY.
AS THE LOW AND ACCOMPANYING FRONTAL SYSTEM SWEEPS THROUGH THE
FORECAST AREA TUESDAY NIGHT AND WEDNESDAY IT WILL GENERATE A CHANCE
OF SOME SNOW. A WEAK RIDGE FOLLOWING THE FRONTAL SYSTEM WILL SWEEP
INTO THE AREA WEDNESDAY NIGHT AND CONTINUING INTO THURSDAY BRINGING
DRIER CONDITIONS TO THE AREA.
&&
.AVIATION (FOR THE 00Z TAF ISSUANCE)...
SCT LOW CLOUDS TRIED TO FORM EARLIER...BUT DRY AIR ON AFTN TAMDAR
SOUNDING FM KSAW DID NOT ALLOW THIS MOISTURE TO FORM INTO A LOW
CLOUD DECK. CONDITIONS AT KSAW SHOULD LOWER THIS EVENING AS BAND
OF SNOW OVR WI ARRIVES. BAND OF SNOW STAYS OVR WESTERN AND SOUTHERN
UPR MI...SO KCMX SHOULD REMAIN VFR THIS EVENING. WINDS WILL CONTINUE
TO INCREASE. AFTER 06Z...CONDITIONS AT KCMX AND KSAW WILL RAPIDLY
DETEREORATE TO VERY LOW IFR IN SNOW AND BLOWING SNOW. LOW CONDITIONS
WILL CONTINUE ALL DAY AT KCMX BUT MAY IMPROVE SLIGHTLY AFT 18Z AT
KSAW...AT LEAST FOR A TIME...AS SNOW TRIES TO LIGHTEN SOME.
DIMINISHING TREND SHOULD BE BRIEF THOUGH AS SNOW IS EXPECTED TO
INCREASE AGAIN FRI EVENING.
&&
.MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)...
A LONG LIVED GALE EVENT WILL CONTINUE THROUGH SATURDAY ACROSS THE
WATERS. STORM FORCE GUSTS ARE POSSIBLE ACROSS LAKE SUPERIOR
ESPECIALLY ACROSS THE FAR WEST WHICH WILL HAVE A STORM WARNING UP
WITH A FAVORED NE WIND FUNNELING DOWN LAKE SUPERIOR WHICH WILL HELP
WITH COASTAL CONVERGENCE AND THE TERRAIN WILL ACT TO FUNNEL THE WIND
AND ACCENTUATE THE WIND SPEEDS. PLAN ON WAVES AS HIGH AS 22 FEET AT
END OF FETCH AND ISSUED A LAKESHORE FLOOD STATEMENT FOR MARQUETTE
COUNTY TO ACCOUNT FOR THAT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WARNING FROM 2 AM EDT /1 AM CDT/ FRIDAY TO 2 PM EDT
/1 PM CDT/ SATURDAY FOR MIZ002-009>013-084.
WINTER STORM WARNING FROM 5 AM FRIDAY TO 8 PM EDT SATURDAY FOR
MIZ004>007-014-085.
BLIZZARD WARNING FROM 5 AM FRIDAY TO 8 PM EDT SATURDAY FOR
MIZ001-003.
LAKE SUPERIOR...
GALE WARNING FROM 8 PM THIS EVENING TO 8 PM EDT SATURDAY FOR
LSZ266-267.
GALE WARNING FROM 8 PM THIS EVENING TO 2 PM EDT SATURDAY FOR
LSZ264-265.
GALE WARNING FROM 8 PM EDT /7 PM CDT/ THIS EVENING TO 6 AM EDT
/5 AM CDT/ SATURDAY FOR LSZ240-244>248.
GALE WARNING FROM 6 AM EDT /5 AM CDT/ FRIDAY TO 6 AM EDT /5 AM
CDT/ SATURDAY FOR LSZ241>243.
STORM WARNING FROM 8 PM THIS EVENING TO 8 PM EDT FRIDAY FOR
LSZ162.
GALE WARNING UNTIL 2 PM EDT SATURDAY FOR LSZ263.
LAKE MICHIGAN...
GALE WARNING FROM 8 PM THIS EVENING TO 8 PM EDT FRIDAY FOR
LMZ221-248-250.
&&
$$
UPDATE...JLA
SHORT TERM...GM
LONG TERM...DLG
AVIATION...JLA
MARINE...GM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
815 PM EDT THU APR 10 2008
ADDED UPDATE SECTION AND UPDATED AVIATION DISCUSSION FOR 00Z TAFS
.UPDATE...
BAND OF MODERATE-HEAVY SNOW WITH UPSTREAM VSBY 1/2SM DOWN TO 1/4SM
PUSHING INTO SW UPR MI. THE BAND IS ASSOCIATED WITH INCREASING MID
LEVEL DEFORMATION AND INITIAL SURGE OF MID LEVEL FRONTOGENESIS. EVEN
A LIGHTNING STRIKE NEAR PARK FALLS WI IN THIS BAND. SINCE THE
HEAVIEST SNOW IS SHIFTING TO THE WEST OF UPR MI EXPECT A LULL AFTER
THIS BAND MOVES ACROSS BEFORE THE WIDESPREAD PCPN OVR SOUTHERN HALF
OF WI MOVES IN TOWARD MIDNIGHT.
UPDATED POPS/WX/SNOW AMOUNTS AS THE INITIAL BAND OF SNOW COMES IN
QUICKER.
DISCUSSION....
SHORT TERM...UP TO 00Z FRI...
UPPER AIR PATTERN CONSISTS OF A 500 MB CLOSED LOW ACROSS SW KS WITH
A STRONG 500 MB TROUGH ACROSS THE WESTERN HIGH PLAINS AND SHORTWAVE
RIDGING ACROSS THE UPPER GREAT LAKES. NAM TAKES THE 500 MB LOW
NORTHEAST TOWARDS THE AREA AND UP INTO THE UPPER GREAT LAKES REGION
ON FRI AND SAT WITH VERY SLOW MOVEMENT TO THE EAST.
LOOKING AT MODEL SOUNDINGS FROM THE GFS...KCMX...KSAW...KERY AND
KIWD ALL SHOW TEMPERATURES THROUGHOUT THE PROFILE REMAINING AT OR
BELOW FREEZING...SO ACCORDING TO THE GFS...PCPN TYPE SHOULD STAY ALL
SNOW. KISQ AND KESC SHOWS A WARM LAYER ALOFT AT 18Z FRI AROUND 800
MB OF 3C AND TEMPERATURES REMAINING ABOVE FREEZING FROM ABOUT 760 MB
TO 860 MB WITH THE SOUNDING REMAINING BELOW ZERO OTHERWISE. KMNM HAS
AN ELEVATED LAYER ABOVE FREEZING 06Z TONIGHT FROM 700 MB TO 850 MB
WITH WARMEST TEMPERATURES AROUND 3C AND THIS ELEVATED LAYER REMAINS
THROUGH 18Z FRI. KIMT HAS ELEVATED WARM LAYER AS WELL AT 18Z OF
2C...OTHERWISE THE SOUNDING REMAINS BELOW FREEZING THE WHOLE TIME.
IRON RIVER HAS ELEVATED LAYER OF 1C AT 18Z BUT VERY LITTLE LAYER OF
ABOUT 50 MB THICK FROM 750MB TO 800 MB. NAM FORECAST SOUNDINGS
SIMILAR TO THE GFS WITH THE WARM LAYER ALOFT AND WHO WOULD SEE SNOW
AND WHO WOULD SEE MIXED PCPN. WILL GO WITH MIXED PCPN FROM SOUTH OF
A LINE FROM IRON RIVER TO GERMFASK AS A FIRST GUESS. NORTH OF THAT
LINE WILL STAY ALL SNOW. FOLLOWED THIS REASONING FOR SNOW AMOUNTS
WITH DIFFERENT RATIOS USED WITH SLEET...RAIN AND SNOW MIXED IN WHICH
WILL LOWER LOWER THE SNOWFALL TOTALS. HAD A HARD TIME TRYING TO
REFLECT WHAT WAS GOING ON WITH THE MIXED PCPN INTO THE SNOW FORECAST
AND COULD HAVE SPEND ANOTHER COUPLE HOURS TRYING TO FINE TUNE
GRIDS...BUT THEN WOULD NOT HAVE TIME TO ISSUE PRODUCTS OR FORECAST
OTHER GRIDS. SNOW AMOUNTS...NOT CONFIDENT ENOUGH THAT I GOT THESE
RIGHT BUT BEST GUESS FOR STORM TOTALS IS UP TO TWO FEET...ESPECIALLY
IN THE HIGHER TERRAIN IN THE HURON MOUNTAINS AND UPSLOPE AREAS OF
MARQUETTE COUNTY WITH LESSER AMOUNTS NEAR THE SHORELINES AND THE
SOUTH AND EAST.
ONE MAJOR CHANGE I DID IS STARTED THE PCPN OFF AS SNOW TONIGHT AS
SOUNDINGS SHOWED AS SUCH WITH EVAPORATIVE COOLING TAKING PLACE WITH
SOME DRY AIR. THIS IS WHAT HAPPENED AT KGRB WHEN PCPN STARTED THIS
AFTERNOON...STARTED OFF BRIEFLY AS RAIN AND THEN QUICKLY CHANGED
OVER TO SNOW. WITH EALIER SNOW...SNOW AMOUNTS WILL BE UP. BLIZZARD
CONDITIONS WITH THE WINDS WILL BE A PROBLEM FOR LATE TONIGHT AND
FRI. DID NOT MAKE TOO MANY MAJOR CHANGES TO THE GOING FORECAST.
.LONG TERM...00Z SAT - 00Z MON
THE LOW WILL LIFT NORTHEAST INTO CENTRAL IOWA DRAGGING THE COLD
FRONT INTO MIDDLE MISSISSIPPI RIVER VALLEY FRIDAY NIGHT. ISENTROPIC
ASCENT AHEAD OF THE FRONT WILL CONTINUE TO DESTABILIZE THE LOW
LEVELS. USING A BLEND OF ECMWF AND GFS STILL SHOWS A .6-.7 INCH QPF
ACROSS THE AREA FRIDAY NIGHT. BUFKIT SUGGESTING A 8 TO 1 RATIO OVER
CENTRAL U.P. WITH A LITTLE HIGHER RATIO OVER THE WEST AND LESS OVER
THE EAST. LOOKING AT THE TEMPERATURE PROFILES...THIS SEEMS
REASONABLE FOR SNOW TOTALS. THIS WILL GIVE US TOTALS OF UP TO 6
INCHES OVER THE HIGHER TERRAIN OF NORTH CENTRAL U.P. AND 2 TO 3
INCHES ELSEWHERE DURING THIS PERIOD. THIS APPEARS TO BE IN LINE WITH
THE HPC GUIDANCE AS WELL.
THE LOW WILL DIG INTO SOUTHWEST LOWER MICHIGAN AS THE LONGWAVE
TROUGH SWEEPS INTO SOUTHEAST ONTARIO ON SATURDAY. Q-VECTOR ENERGY
WILL WEAKEN OVER THE AREA. AS THE LOW SWEEPS SOUTHEAST...DRIER AIR
WILL START TO INVADE THE FORECAST AREA FROM THE NORTHWEST
DIMINISHING THE CHANCES OF SNOW. GFS/ECMWF CONTINUE TO SHOW QPF OVER
THE AREA ON THE ORDER OF .4 TO .5 INCHES OVER U.P. KEEPING WITH THE
SAME RATIO...WILL GIVE SNOW TOTALS ON 1 TO 3 INCHES OVER THE AREA
WITH THE HEAVIEST OVER THE NORTHERN U.P.
THE LONGWAVE TROUGH WILL CONTINUE TO DOMINATE THE GREAT LAKES REGION
SATURDAY NIGHT INTO SUNDAY. A WEAK SHORTWAVE...WITH INCREASED
Q-VECTOR CONVERGENCE...SLIDING THROUGH THE TROUGH WILL ENTER INTO
THE FORECAST AREA. THE SURFACE RIDGE WILL SHIFT INTO NORTHERN
ONTARIO...THE UPPER MISSISSIPPI RIVER VALLEY AND THE FORECAST AREA.
THE AIR MASS WILL BE LITTLE DRY. THUS WILL KEEP A CHANCE OF SNOW
WILL CONTINUE OVER THE NORTHERN U.P. AS WINDS WILL REMAIN OUT OF THE
NORTH DRAWING SOME MOISTURE FROM THE LAKE.
THE CLOSED LOW OVER SOUTHERN QUEBEC WILL SLIDE EAST INTO THE
CANADIAN MARITIME SUNDAY NIGHT AND MONDAY. THE ACCOMPANYING LONGWAVE
TROUGH WILL EDGE INTO THE LOWER GREAT LAKES. A WEAK SHORTWAVE WILL
SWEEP THROUGH THE FORECAST AREA. THE RIDGE WILL MOVE INTO NORTHERN
ONTARIO AS ANOTHER LONGWAVE TROUGH EDGES INTO THE PACIFIC NORTHWEST.
THE SURFACE RIDGE WILL THEN NAVIGATE OVER THE UPPER GREAT LAKES. THE
LOWER GREAT LAKES LONGWAVE TROUGH WILL REACH THE EAST COAST ON
TUESDAY...WHILE WEST COAST TROUGH WANDERS INTO SOUTH CENTRAL CANADA
AND THE RIDGE WILL MOVE ACROSS UPPER MICHIGAN. THE SURFACE RIDGE
WILL REACH EASTERN CONUS AS A SURFACE LOW AND ACCOMPANYING COLD
FRONT TRACKS THROUGH THE NORTHERN PLAINS. ISENTROPIC ASCENT AHEAD OF
THE LOW WILL GENERATE A SOME RAIN SHOWERS OVER WESTERN LAKE SUPERIOR
LATE ON TUESDAY.
AS THE LOW AND ACCOMPANYING FRONTAL SYSTEM SWEEPS THROUGH THE
FORECAST AREA TUESDAY NIGHT AND WEDNESDAY IT WILL GENERATE A CHANCE
OF SOME SNOW. A WEAK RIDGE FOLLOWING THE FRONTAL SYSTEM WILL SWEEP
INTO THE AREA WEDNESDAY NIGHT AND CONTINUING INTO THURSDAY BRINGING
DRIER CONDITIONS TO THE AREA.
&&
.AVIATION (FOR THE 00Z TAF ISSUANCE)...
SCT LOW CLOUDS TRIED TO FORM EARLIER...BUT DRY AIR ON AFTN TAMDAR
SOUNDING FM KSAW DID NOT ALLOW THIS MOISTURE TO FORM INTO A LOW
CLOUD DECK. CONDITIONS AT KSAW SHOULD LOWER THIS EVENING AS BAND
OF SNOW OVR WI ARRIVES. BAND OF SNOW STAYS OVR WESTERN AND SOUTHERN
UPR MI...SO KCMX SHOULD REMAIN VFR THIS EVENING. WINDS WILL CONTINUE
TO INCREASE. AFTER 06Z...CONDITIONS AT KCMX AND KSAW WILL RAPIDLY
DETEREORATE TO VERY LOW IFR IN SNOW AND BLOWING SNOW. LOW CONDITIONS
WILL CONTINUE ALL DAY AT KCMX BUT MAY IMPROVE SLIGHTLY AFT 18Z AT
KSAW...AT LEAST FOR A TIME...AS SNOW TRIES TO LIGHTEN SOME.
DIMINISHING TREND SHOULD BE BRIEF THOUGH AS SNOW IS EXPECTED TO
INCREASE AGAIN FRI EVENING.
&&
.MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)...
A LONG LIVED GALE EVENT WILL CONTINUE THROUGH SATURDAY ACROSS THE
WATERS. STORM FORCE GUSTS ARE POSSIBLE ACROSS LAKE SUPERIOR
ESPECIALLY ACROSS THE FAR WEST WHICH WILL HAVE A STORM WARNING UP
WITH A FAVORED NE WIND FUNNELING DOWN LAKE SUPERIOR WHICH WILL HELP
WITH COASTAL CONVERGENCE AND THE TERRAIN WILL ACT TO FUNNEL THE WIND
AND ACCENTUATE THE WIND SPEEDS. PLAN ON WAVES AS HIGH AS 22 FEET AT
END OF FETCH AND ISSUED A LAKESHORE FLOOD STATEMENT FOR MARQUETTE
COUNTY TO ACCOUNT FOR THAT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WARNING FROM 2 AM EDT /1 AM CDT/ FRIDAY TO 2 PM EDT
/1 PM CDT/ SATURDAY FOR MIZ002-009>013-084.
WINTER STORM WARNING FROM 5 AM FRIDAY TO 8 PM EDT SATURDAY FOR
MIZ004>007-014-085.
BLIZZARD WARNING FROM 5 AM FRIDAY TO 8 PM EDT SATURDAY FOR
MIZ001-003.
LAKE SUPERIOR...
GALE WARNING FROM 8 PM THIS EVENING TO 8 PM EDT SATURDAY FOR
LSZ266-267.
GALE WARNING FROM 8 PM THIS EVENING TO 2 PM EDT SATURDAY FOR
LSZ264-265.
GALE WARNING FROM 8 PM EDT /7 PM CDT/ THIS EVENING TO 6 AM EDT
/5 AM CDT/ SATURDAY FOR LSZ240-244>248.
GALE WARNING FROM 6 AM EDT /5 AM CDT/ FRIDAY TO 6 AM EDT /5 AM
CDT/ SATURDAY FOR LSZ241>243.
STORM WARNING FROM 8 PM THIS EVENING TO 8 PM EDT FRIDAY FOR
LSZ162.
GALE WARNING UNTIL 2 PM EDT SATURDAY FOR LSZ263.
LAKE MICHIGAN...
GALE WARNING FROM 8 PM THIS EVENING TO 8 PM EDT FRIDAY FOR
LMZ221-248-250.
&&
$$
UPDATE...JLA
SHORT TERM...GM
LONG TERM...DLG
AVIATION...JLA
MARINE...GM
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1210 PM EDT WED APR 9 2008
.UPDATE...
WILL THROW IN THE TOWEL AND INCREASE CLOUD COVER THIS AFTERNOON
AND LOWER TEMPS SOME MORE. ACARS FLIGHT OUT OF DTW SHOWS A VERY STRONG
INVERSION AT OR JUST ABOVE 4000 FEET. THE EARLIER BREAKS THIS MORNING HAVE
FILLED IN...AS CLOUDS HAVE FLATTENED OUT. STILL EXPECTING SKIES TO
CLEAR OUT VERY LATE TODAY/THIS EVENING AS INVERSION HEIGHTS
CONTINUE TO LOWER AND LOW LEVEL COLD ADVECTION SHUTS OFF.
&&
.PREV DISCUSSION...ISSUED 718 AM EDT WED APR 9 2008
AVIATION...
COLD FRONT HAS PASSED ALL SITES EARLY THIS MORNING...WITH STRATUS IN
THE MVFR RANGE OVERSPREADING THE REGION AS SOUTHWEST WINDS GUST TO
25 KNOTS OR MORE. WINDS WILL REMAIN GUSTY THIS MORNING...AND THEN
SUBSIDE GRADUALLY DURING THE MID/LATE AFTERNOON AS SURFACE GRADIENT
SLACKENS. STRATUS IS ALSO EXPECTED TO SCATTERED OUT...BUT THIS WILL
LIKELY TAKE MUCH OF THE DAY. AS HIGH PRESSURE RIDGES INTO THE AREA
THIS EVENING...WINDS WILL WEAKEN AND VEER TO THE NORTH. NAM12 BRINGS
LOWER STRATUS BACK SOUTH INTO THE AREA...AND WILL TENTATIVELY BUY
THAT SCENARIO...ESPECIALLY FOR KMBS/KFNT...GIVEN THE EXTENSIVE DECK
OF STRATUS CURRENTLY SHOWING UP ON SATELLITE BACK INTO THE NORTHERN
MISSISSIPPI VALLEY NORTH INTO CANADA.
PREV DISCUSSION...ISSUED 423 AM EDT WED APR 9 2008
SHORT TERM...TODAY
SHOWERS AND THUNDERSTORMS WILL RACE THROUGH THE AREA EARLY THIS
MORNING...GENERALLY DURING THE PRE-DAWN HOURS...AS A COLD FRONT
WRAPS EAST/NORTHEAST AROUND SURFACE LOW PRESSURE NOW TRACKING INTO
NORTHERN LAKE MICHIGAN. SEVERE WEATHER IS NOT ANTICIPATED WITH THE
STORMS. HOWEVER...WIND GUSTS ALONG/BEHIND THE COLD FRONT WILL REACH
35 MPH FOR AN HOUR OR TWO. WOULD EXPECT MUCH OF THE ACTIVITY TO BE
EAST OF THE AREA BY 12Z...WITH PERHAPS A LINGERING SHOWER/STORM EAST
OF I 75 FOR ANOTHER HOUR OR TWO AFTER THAT.
WINDS WILL REMAIN GUSTY INTO THE DAYTIME HOURS...AND MAY ONCE AGAIN
REACH 35 OR 40 MPH AFTER BETTER LOW LEVEL MIXING ENSUES BY THE
MIDDLE OF THE MORNING. THE STRONG WINDS WILL EXIST ALONG/NORTH OF I
69 WHERE SURFACE GRADIENT REMAINING TIGHTEST WITH A CLOSER PROXIMITY
TO THE AFOREMENTIONED LOW PRESSURE SYSTEM...WHICH LIFTS NORTH OF
LAKE HURON DURING THE MORNING.
LOW LEVEL STRATUS IN THE WAKE OF THE COLD FRONT WILL SCATTERED OUT
AS THE SYSTEM RACES INTO CANADA AND DRIER AIR ADVECTS INTO THE AREA
DURING THE MORNING. TEMPERATURES WILL BE DEPENDENT ON CLOUD COVER
AND GENERALLY AGREE WITH THE GOING FORECAST...RANGING FROM THE LOW
TO MID 50S NORTH WITH MORE CLOUDS TO LOWER 60S SOUTH WHERE MORE IN
THE WAY OF SUN CAN BE EXPECTED. ALSO...THE BEST COLD AIR ADVECTION
GIVEN THE NORTHEAST TRAJECTORY OF THIS SYSTEM WILL BE FOUND OVER THE
NORTHERN CWA.
LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY
THE DEEP UPPER LEVEL TROUGH THAT WILL BRING THE NEXT ROUND OF ACTIVE
WEATHER TO SOUTHEAST MICHIGAN TOWARDS THE END OF THE WEEK IS
BEGINNING TO TAKE SHAPE OVER THE WESTERN STATES. A ROBUST UPPER
LEVEL JET SEEN ON WATER VAPOR APPROACHING THE WEST COAST WILL MOVE
THROUGH THE TROUGH...LEADING TO FURTHER DEEPENING AS THE TROUGH
TAKES ON A NEGATIVE TILT OVER THE PLAINS ON THURSDAY. STRONG SURFACE
CYCLOGENESIS WILL OCCUR OVER THE PLAINS WITH DEEP SOUTHERLY FLOW
SETTING UP FROM THE GULF COAST TO THE OHIO VALLEY. MODELS INDICATE
AN IMPRESSIVE 60+ KNOT LLJ FOCUSED UP THE MISSISSIPPI VALLEY ON
THURSDAY...TRANSPORTING ABUNDANT MOISTURE NORTH AHEAD OF THIS TROUGH.
DESPITE A DRY AIRMASS IN PLACE ON THURSDAY MORNING WITH MEAN LAYER
RH BELOW 40 PERCENT...STRONG ISENTROPIC ASCENT IN THE 295-305K
LAYER WILL BE ENOUGH TO ALLOW RAIN SHOWERS TO SPREAD IN FROM THE
SOUTH BY THURSDAY AFTERNOON. THE ONLY EXCEPTION TO THIS MAY BE
ACROSS THE THUMB WHERE DRY EASTERLY FLOW IN THE LOW LEVELS MAY
DELAY THE ONSET UNTIL THURSDAY NIGHT AND HAVE RAISED POPS
ELSEWHERE. WIDESPREAD RAIN STILL LOOKS ON TRACK THURSDAY NIGHT AS
850MB DEWPOINTS CLIMB TO 8C AND PRECIPITABLE WATER VALUES APPROACH
1.50 INCHES NEAR THE SOUTHERN BORDER. A VORT LOBE LIFTS THROUGH
THE AREA AHEAD OF THE MID LEVEL DRY-SLOT PROVIDING STRONG LIFT TO
AN ALREADY UNSTABLE AIRMASS. THUNDERSTORMS CONTINUE TO LOOK LIKELY
WITH SHOWALTERS DROPPING TO BELOW ZERO AND LAPSE RATES APPROACHING
7C/KM IN THE 700-500MB LAYER.
SURFACE WARM FRONT IS EXPECTED TO REACH NORTHERN ILLINOIS/INDIANA
THURSDAY NIGHT...THEN MAKE A PUSH NORTH INTO SOUTHERN LOWER MICHIGAN
ON FRIDAY AHEAD OF THE OCCLUDED FRONT. THE GFS/ECMWF LEAVE MORE
SPACING BETWEEN THE TWO FRONTS...THUS LEADING TO MORE INSTABILITY
FOR SOUTHEAST MICHIGAN FRIDAY AFTERNOON. THE NAM DOES NOT LIFT THE
WARM FRONT AS FAR NORTH INDICATING THAT THE TRI-CITIES AND NORTHERN
THUMB WILL ONLY SEE HIGHS REACH THE UPPER 40S ON FRIDAY. WILL TAKE
THE NAM INTO CONSIDERATION AS IT MAY HAVE A BETTER HANDLE ON LAKE
HURON TEMPERATURES AND WILL LIFT THE WARM FRONT NORTH TO AROUND
THE I-69 CORRIDOR. IF WE END UP IN THE WARM SECTOR FRIDAY
AFTERNOON...STRONG THUNDERSTORMS AND PERHAPS SEVERE WEATHER
REMAIN A POSSIBILITY. MODELS IN AGREEMENT SHOWING 500-800 J/KG OF
SURFACE BASED CAPE ALREADY IN PLACE WHEN THE 500MB FRONT MOVES
THROUGH DURING THE AFTERNOON. STRONG SHEER AND DYNAMICS WILL BE
SUFFICIENT TO PRODUCE SEVERE WEATHER IF INSTABILITY IS HIGH ENOUGH
AND WILL KEEP A CLOSE EYE ON THE EVOLUTION OF THIS PATTERN.
A MUCH COOLER WEEKEND IS IN STORE AS COLD AIR ADVECTION CONTINUES
THROUGH THE DAY ON SATURDAY AS THE SURFACE LOW MEANDERS TOWARDS
THE EASTERN GREAT LAKES. RAIN SHOWERS ON SATURDAY WILL TRANSITION
TO LIGHT SNOW SHOWERS BY SATURDAY NIGHT AS THE BOUNDARY LAYER
COOLS AND THE DEFORMATION AXIS PASSES OVERHEAD. 850MB TEMPS FALL
TO AROUND -6C WITH TEMPERATURES ONLY CLIMBING BACK INTO THE LOW TO
MID 40S ON SUNDAY.
MARINE...
LOW PRESSURE WILL TRACK NORTHEAST INTO ONTARIO THIS MORNING BRINGING
A COLD FRONT THROUGH THE CENTRAL GREAT LAKES. GALE WARNINGS REMAIN
IN EFFECT FOR LAKE HURON TODAY WITH A CONTINUED TIGHT PRESSURE
GRADIENT AND COLD ADVECTION CAUSING WIND GUSTS TO 40 KNOTS. WINDS
WILL DECREASE TO LESS THAN 20 KNOTS BY THURSDAY MORNING AS A SURFACE
RIDGE BUILDS OVER THE REGION.
A MORE INTENSE LOW PRESSURE SYSTEM IS FORECASTED TO IMPACT THE
REGION THURSDAY NIGHT INTO FRIDAY...BRINGING THE RISK FOR
THUNDERSTORMS AND STRONG WINDS ONCE AGAIN. GALE WARNINGS MAY BE
NEEDED OVER LAKE HURON AS THE PRESSURE GRADIENT TIGHTENS CAUSING
EASTERLY WINDS TO INCREASE WITH GUSTS TO 40 KNOT GALES AHEAD OF
THIS SYSTEM. PEAK WINDS ARE EXPECTED THURSDAY NIGHT WITH WINDS
ACROSS THE SOUTHERN PART OF LAKE HURON DECREASING ON FRIDAY AS A
WARM FRONT APPROACHES FROM THE SOUTH.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...
GALE WARNING...LHZ421-LHZ422-LHZ441-LHZ462...UNTIL 5 PM WEDNESDAY.
GALE WARNING...LHZ361-LHZ362-LHZ363...UNTIL MIDNIGHT THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT
HURON...UNTIL 5 PM WEDNESDAY.
LAKE ST CLAIR...
SMALL CRAFT ADVISORY...UNTIL 5 PM WEDNESDAY.
MI WATERS OF LAKE ERIE...
SMALL CRAFT ADVISORY...UNTIL 5 PM WEDNESDAY.
&&
$$
UPDATE.......SF
AVIATION.....DG
SHORT TERM...DG
LONG TERM....KEC
MARINE.......KEC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
416 AM EDT WED APR 9 2008
LATEST UPDATE...ALL BUT AVIATION...
.SYNOPSIS...(416 AM EDT WED APR 9 2008)
LOW PRESSURE NEAR HOLLAND WILL MOVE INTO QUEBEC BY THIS AFTERNOON.
SHOWERS AND THUNDERSTORMS EARLY THIS MORNING WILL GIVE WAY TO MOSTLY
CLOUDY SKIES BY NOON AND THEN PARTLY SUNNY SKIES LATE IN THE DAY.
ANOTHER STORM SYSTEM WILL DEVELOP OVER THE PLAINS THURSDAY AND PUSH
A WARM FRONT NORTH THURSDAY NIGHT AND FRIDAY. MORE SHOWERS AND
THUNDERSTORMS ARE POSSIBLE DURING THAT TIME FRAME TOO. TEMPERATURES
WILL COOL BACK INTO THE 40S FOR THE WEEKEND.
&&
.SHORT TERM...(416 AM EDT WED APR 9 2008)
(TODAY THROUGH FRIDAY)
ONGOING CONVECTION ALONG THE COLD FRONT WILL PUSH EAST BY SUNRISE
THIS MORNING. WE SHOULD SEE A DECREASING CLOUD TREND THIS AFTERNOON
AS A RIDGE NOSES SOUTH FROM NEAR JAMES BAY. THE NEXT CHANCE OF RAIN
WILL COME THURSDAY AS A LOW OVER KANSAS PUSHES A WARM FRONT NORTH
INTO LOWER MICHIGAN. THE MODELS HAVE GONE BACK AND FORTH WITH THIS
SYSTEM AS TO WHETHER AND WHEN IT OCCLUDES AND WHETHER OR NOT THE
WARM FRONT MAKES IT INTO THE CWA. LATEST GUIDANCES SUGGESTS THAT THE
WARM FRONT WILL INDEED MAKE IT INTO LOWER MICHIGAN LATE THURSDAY
NIGHT AND EARLY FRIDAY MORNING. THAT COULD BE TROUBLE FOR THE CWA AS
THIS WILL BE A VERY DYNAMIC SYSTEM. AS THE WARM FRONT MOVES INTO THE
CWA FROM THE SOUTH...GFS SHOWS SHEAR VALUES NEAR 100 KTS AND STRONG
HELICITY ACROSS THE CWA. BUFKIT HODOGRAPHS ARE REALLY IMPRESSIVE
THURSDAY NIGHT. SFC BASED LI/S NEAR -5C AND TOTAL TOTALS IN THE MID
50S.
A 60-70KT LLJ WILL BRING MOISTURE INTO THE REGION. THE NAM AND ECMWF
ARE A LITTLE QUICKER WITH THE OCCLUSION AND ARE WEAKER WITH THE
SHEAR. CERTAINLY...IT LOOKS LIKE THE HIGHER SEVERE THREAT WILL BE
SOUTH OF THE CWA...BUT IT/S SOMETHING WE/LL KEEP AN EYE ON.
&&
.LONG TERM...(416 AM EDT WED APR 9 2008)
(FRIDAY NIGHT THROUGH TUESDAY)
NO SIGNIFICANT CHANGES MADE TO THE EXTENDED AS THE UPPER LOW BRINGS
SOME MIXED RAIN AND SNOW SHOWERS AND MAXES IN THE MID 40S THIS
WEEKEND. ONLY GRADUAL MODERATION IN TEMPS INTO EARLY NEXT WEEK AS
SHARP H5 TROUGH SLOWLY MOVES EAST.
&&
.AVIATION...(1225 AM EDT WED APR 9 2008)
THE RADAR SHOWS A LINE OF THUNDERSTORMS CROSSING LAKE MICHIGAN INTO
THE US-131 AREA BY 1 AM AND TO LANSING AND JACKSON BETWEEN 2 AND 3
AM. GUSTY WINDS ARE POSSIBLE AS THE LINE MOVES THROUGH BUT SHALLOW
STABLE AIR AS SEEN ON TAMDAR WILL PREVENT WINDS FROM GUSTING TO MORE
THAN 30 KNOTS.
ONCE THAT LINE MOVES THROUGH LOW CLOUDS MOVE IN QUICKLY WITH THE
COLD ADVECTION BEHIND THE FRONT. MAY EVEN BE SOME SPRINKLES OR LIGHT
RAIN BUT I DID NOT PUT THAT IN THE TAFS AS THE TOPS OF THE LOW
CLOUDS WILL BE BELOW THE DGZ. HOWEVER THERE IS DECENT LIFT BETWEEN
1000 AND 2000 FT TILL NEARLY 18Z. CLOUD TEMPERATURES WILL BE
BETWEEN 0C AND -2C THROUGH.
THE CYCLONIC FLOW BEHIND THIS SYSTEM WILL NOT MOVE OUT UNTIL LATE
AFTERNOON. I EXPECT THE CLEARING OF THE LOW CLOUDS WILL TAKE TILL
THEN.
&&
.MARINE...(416 AM EDT WED APR 9 2008)
WINDS AND WAVE WILL CONTINUE TO INCREASE IN THE WAKE OF THE COLD
FRONT. THE WINDS AND WAVES WILL DIMINISH LATE WEDNESDAY AS HIGH
PRESSURE BUILDS INTO THE REGION.
&&
.HYDROLOGY...(416 AM EDT WED APR 9 2008)
HPC GUIDANCE SUGGESTS ONE TO TWO INCHES OF RAIN COULD FALL THURSDAY
AFTERNOON AND NIGHT... WHICH MAY CREATE SOME HYDRO ISSUES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY FOR ST JOE TO MANISTEE THROUGH 6 PM EDT
TODAY.
&&
$$
SYNOPSIS: 93
SHORT TERM: 93
LONG TERM: OSTUNO
AVIATION: WDM
MARINE: 93
HYDROLOGY: 93
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
1127 PM CDT THU APR 10 2008
.UPDATE...
UPDATED FOR 06Z AVIATION DISCUSSION BELOW.
&&
.DISCUSSION...
THE CHALLENGE WITH THE FORECAST IS CLEARLY THE IMPACT OF THE LATE
WINTER/EARLY SPRING SYSTEM THE NEXT 24 TO 36 HOURS.
GOES WV LOOP SHOWING AN EXTREMELY IMPRESSIVE UPPER LOW CENTERED
OVER KANSAS WITH A DRY MID-LEVEL PUNCH SURGING NORTHWARD ON 100+
KT 500MB WINDS INTO SRN MN. IN THE LAYER BELOW THIS...WARM AIR HAS
NOSED INTO THE FORECAST AREA ON ESE 750-925MB WINDS EARLIER TODAY.
PRECIP TYPE IN MN HAS BEEN PREDOMINATELY RAIN OR LIGHT SLEET.
TAMDAR SOUNDINGS AROUND NOON IN AND NEAR MSP SHOWED A WARM LAYER
BETWEEN 2 AND 5C WITHIN THE 2500 TO 7000 FT LAYER. DOPPLER BRIGHT
BANDING ALSO INDICATING MELTING AND FREEZING LAYERS NEAR THESE
HEIGHTS. THIS WARM LAYER IS ALSO VERY DRY ON THOSE SOUNDINGS AND
ON MODEL ANALYSIS. THUS..EVAPORATIVE COOLING WILL LIKELY BEGIN TO
TRANSITION SOME PRECIP TO SNOW...ESPECIALLY WEST OF A MORA TO
NEW ULM LINE BY MID-EVENING. THE U.S. HIGHWAY 8 CORRIDOR OF WI
ALSO IS LIKELY FAR ENOUGH NORTH FOR A MORE SIMPLE CHANGEOVER TO
SNOW. WINDS HAVE GUSTED TO 50 MPH IN PLACES OF SOUTH CTRL MN AND
EXPECT THAT TO CONTINUE INTO THIS EVE WITH ONLY A VERY SLOW
DECREASE AS LOW BECOMES STACKED AND DEEPENING CEASES.
THE SURGE OF PRECIP FROM SRN MN IS ON A NOSE OF HIGH 850-700MB
THETA-E WHICH WILL NOSE NORTHWARD THIS EVE WITH NEARLY FULL
COVERAGE OF PRECIP. MOISTURE CONVERGENCE IN THIS LAYER IS
SUBSTANTIAL OVER WEST CTRL MN...AGAIN THE AREA WHERE THE THERMAL
PROFILE FAVORS PREDOMINATELY ALL SNOW. BANDING-LIKE SIGNATURES
ALREADY SHOWING UP ON RADAR AND CROSS SECTIONS FROM GUIDANCE
INDICATE SOME INDUCED INSTABILITY FROM FRONTOGENESIS IS LIKELY.
MIXING RATIOS FEEDING IN RANGE FROM 4 TO 6 G/KG ON
GUIDANCE...HOWEVER THERE MAY SOME OF THIS TAKEN UP BY SFC BASED
AND ELEVATED CONVECTION ACROSS NRN MO AND INTO IA. PV SFCS
INDICATE A GREAT DEAL OF LATENT HEAT RELEASE THIS EVE TO OUR
SOUTH FROM THIS CONVECTION...WHICH COMBINED WITH DRY SLOT AND
ASSOCIATED LOSS OF ICE NUCLEI...MAY SIGNIFICANTLY LOWER SNOWFALL
AMOUNTS PREDICTED THIS EVE ACROSS CTRL MN AND THE AFOREMENTIONED
AREA OF WEST CTRL WI. THIS HAS ALREADY PROMPTED CHANGING A PORTION
OF THE WARNING TO AN ADVISORY. UNCERTAINTY CONTINUES FOR THE
EASTERN PORTION OF THE WARNING AS WELL...WITH A SHARP GRADIENT IN
SNOWFALLS LIKELY. THE TREND IS DOWN RIGHT NOW IN SNOWFALL AMOUNTS
FOR THE TWIN CITIES AND OTHER AREAS OF ERN AND SRN MN. THINGS
STILL LOOK ON PAR FOR WEST CTRL MN...WITH THE WINDS ALSO
GENERATING SOME BLOWING OF SNOW.
SOME ELEVATED CONVECTION LIKELY TO MAKE IT INTO FAR SOUTHEAST
FORECAST AREA TONIGHT GIVEN SATELLITE TRENDS AND SURGE OF
K-INDICES. THIS SHOULD ONLY OVERSPREAD THE AREAS WHERE LIQUID
PRECIP IS EXPECTED IN SOUTH CENTRAL MN AND SOUTH OF I-94 IN WEST
CTRL WI.
COME FRIDAY THE SYSTEM WILL SHIFT EASTWARD WITH A TROUGH OF WARM
AIR ALOFT /TROWAL/ WRAPPING AROUND AND INTO THE FORECAST AREA.
MOIST ASCENT ON THIS WILL HELP TO CONTINUE SNOW DURING THE DAY
FRIDAY AND WITH THE COOLING PROFILE SPREAD IT EAST SOUTHEAST
ACROSS THE FORECAST AREA. TOUGH TO SAY STILL AT THIS POINT IF ANY
OF THE SNOW ON FRI WILL BE HEAVY. THERE ARE SOME SIGNATURES OF
FORCING WITHIN THIS AREA OF DEFORMATION BUT THERE HAS BEEN LITTLE
AGREEMENT ON PLACEMENT OF THIS. DURING THE DAY FRIDAY A 2 TO 4
INCH ADDITIONAL SNOW LOOKS REASONABLE FOR CTRL AND ERN MN AND WRN
WI. AGAIN...FOR SEVERAL AREAS INCLUDING THE SOUTHEAST HALF OF THE
TWIN CITIES...THIS WILL BE THE BEST CHANCE FOR SNOW ACCUMULATION.
WINDS WILL CONTINUE ON FRI LEADING TO SOME BLOWING OF PRIMARILY
THE FALLING SNOW IN RURAL OPEN AREAS...FURTHER REDUCING
VISIBILITIES.
SNOW SHOULD WIND DOWN QUICKLY TO A MORE OF A LIGHT SNOW/SNOW
SHOWERS FRI NIGHT WITH WINDS CONTINUING INTO SAT. COLD AIR
ADVECTION AHEAD OF A CANADIAN HIGH WILL KEEP TEMPS BELOW NORMAL
THIS WEEKEND. SOME NEAR 20 DEGREE LOWS ARE EXPECTED IN WEST CTRL
AREAS OVER THE FRESH SNOW. BEYOND...HAVE GONE EASY WITH THE WARM-
UP THROUGH MON AND INTO TUES...WITH THE LARGEST H8 TEMP
STANDARDIZED ANOMALIES ABOVE NORMAL COMING ON WEDS. 60 DEGREES OR
NEAR IT LOOKS LIKE IT SHOULD BE BACK DURING THE MIDDLE OF NEXT
WEEK.
&&
.AVIATION.../06Z TAF ISSUANCE/
STILL A VERY TOUGH FORECAST WITH MAIN ISSUES BEING PRECIP
TYPE...DEALING WITH ISOLD THUNDER POSSIBILITIES...AND WINDS. DRY
SLOT MOVING INTO SRN MN ATTM...WITH BANDS OF SNOW MOVING ACRS
STC/AXN. AXN STILL SHUD SEE BOUTS OF BLIZZARD CONDS DURG THE FIRST
6 HRS OF THE TAF PD...BEFORE WINDS BEGIN TO TAPER AS THE LO PUSHES
EWRD. HEAVIEST SNOW SHUD MOVE INTO STC/RWF/MSP DURG THE MRNG HRS
TOMORROW...WITH RNH/EAU FOLLOWING IN THE LATE MRNG/EARLY AFTN...AS
DEFORMATION ZONE MOVES EWRD. MOST SITES SHUD SEE A PERIOD OF 1/4
OR 1/2SM VSBYS IN THE HEAVIEST SNOW. DRIER AIR WILL BEGIN TO MOVE
INTO THE RGN LATE IN THE TAF PD FROM THE W...AND COMBINED WITH
WEAKENING FORCING...WILL LEAD TO GRADUALLY IMPROVING CONDS TOWARD
06Z...ESP AT AXN/RWF...ALTHO RESTRICTIONS SHUD STILL EXIST. WINDS
WILL REMAIN GUSTY...WITH 15 TO 20KTS FROM THE N AND NW BY THE END
OF THE VALID TAF PD...AND GUSTS NR 25KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 7 AM CDT SATURDAY FOR ANOKA-BENTON-
CARVER-CHIPPEWA-CHISAGO-DOUGLAS-HENNEPIN-ISANTI-KANABEC-
KANDIYOHI-LAC QUI PARLE-MCLEOD-MEEKER-MILLE LACS-MORRISON-
POPE-REDWOOD-RENVILLE-SHERBURNE-SIBLEY-STEARNS-STEVENS-
SWIFT-TODD-WRIGHT-YELLOW MEDICINE.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT SATURDAY FOR BROWN-DAKOTA-
MARTIN-NICOLLET-RAMSEY-SCOTT-WASHINGTON-WATONWAN.
WI...WINTER STORM WARNING UNTIL 7 AM CDT SATURDAY FOR BARRON-POLK-
RUSK.
&&
$$
MTF/KAT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
337 PM CDT THU APR 10 2008
.DISCUSSION...
THE CHALLENGE WITH THE FORECAST IS CLEARLY THE IMPACT OF THE LATE
WINTER/EARLY SPRING SYSTEM THE NEXT 24 TO 36 HOURS.
GOES WV LOOP SHOWING AN EXTREMELY IMPRESSIVE UPPER LOW CENTERED
OVER KANSAS WITH A DRY MID-LEVEL PUNCH SURGING NORTHWARD ON 100+
KT 500MB WINDS INTO SRN MN. IN THE LAYER BELOW THIS...WARM AIR HAS
NOSED INTO THE FORECAST AREA ON ESE 750-925MB WINDS EARLIER TODAY.
PRECIP TYPE IN MN HAS BEEN PREDOMINATELY RAIN OR LIGHT SLEET.
TAMDAR SOUNDINGS AROUND NOON IN AND NEAR MSP SHOWED A WARM LAYER
BETWEEN 2 AND 5C WITHIN THE 2500 TO 7000 FT LAYER. DOPPLER BRIGHT
BANDING ALSO INDICATING MELTING AND FREEZING LAYERS NEAR THESE
HEIGHTS. THIS WARM LAYER IS ALSO VERY DRY ON THOSE SOUNDINGS AND
ON MODEL ANALYSIS. THUS..EVAPORATIVE COOLING WILL LIKELY BEGIN TO
TRANSITION SOME PRECIP TO SNOW...ESPECIALLY WEST OF A MORA TO
NEW ULM LINE BY MID-EVENING. THE U.S. HIGHWAY 8 CORRIDOR OF WI
ALSO IS LIKELY FAR ENOUGH NORTH FOR A MORE SIMPLE CHANGEOVER TO
SNOW. WINDS HAVE GUSTED TO 50 MPH IN PLACES OF SOUTH CTRL MN AND
EXPECT THAT TO CONTINUE INTO THIS EVE WITH ONLY A VERY SLOW
DECREASE AS LOW BECOMES STACKED AND DEEPENING CEASES.
THE SURGE OF PRECIP FROM SRN MN IS ON A NOSE OF HIGH 850-700MB
THETA-E WHICH WILL NOSE NORTHWARD THIS EVE WITH NEARLY FULL
COVERAGE OF PRECIP. MOISTURE CONVERGENCE IN THIS LAYER IS
SUBSTANTIAL OVER WEST CTRL MN...AGAIN THE AREA WHERE THE THERMAL
PROFILE FAVORS PREDOMINATELY ALL SNOW. BANDING-LIKE SIGNATURES
ALREADY SHOWING UP ON RADAR AND CROSS SECTIONS FROM GUIDANCE
INDICATE SOME INDUCED INSTABILITY FROM FRONTOGENESIS IS LIKELY.
MIXING RATIOS FEEDING IN RANGE FROM 4 TO 6 G/KG ON
GUIDANCE...HOWEVER THERE MAY SOME OF THIS TAKEN UP BY SFC BASED
AND ELEVATED CONVECTION ACROSS NRN MO AND INTO IA. PV SFCS
INDICATE A GREAT DEAL OF LATENT HEAT RELEASE THIS EVE TO OUR
SOUTH FROM THIS CONVECTION...WHICH COMBINED WITH DRY SLOT AND
ASSOCIATED LOSS OF ICE NUCLEI...MAY SIGNIFICANTLY LOWER SNOWFALL
AMOUNTS PREDICTED THIS EVE ACROSS CTRL MN AND THE AFOREMENTIONED
AREA OF WEST CTRL WI. THIS HAS ALREADY PROMPTED CHANGING A PORTION
OF THE WARNING TO AN ADVISORY. UNCERTAINTY CONTINUES FOR THE
EASTERN PORTION OF THE WARNING AS WELL...WITH A SHARP GRADIENT IN
SNOWFALLS LIKELY. THE TREND IS DOWN RIGHT NOW IN SNOWFALL AMOUNTS
FOR THE TWIN CITIES AND OTHER AREAS OF ERN AND SRN MN. THINGS
STILL LOOK ON PAR FOR WEST CTRL MN...WITH THE WINDS ALSO
GENERATING SOME BLOWING OF SNOW.
SOME ELEVATED CONVECTION LIKELY TO MAKE IT INTO FAR SOUTHEAST
FORECAST AREA TONIGHT GIVEN SATELLITE TRENDS AND SURGE OF
K-INDICES. THIS SHOULD ONLY OVERSPREAD THE AREAS WHERE LIQUID
PRECIP IS EXPECTED IN SOUTH CENTRAL MN AND SOUTH OF I-94 IN WEST
CTRL WI.
COME FRIDAY THE SYSTEM WILL SHIFT EASTWARD WITH A TROUGH OF WARM
AIR ALOFT /TROWAL/ WRAPPING AROUND AND INTO THE FORECAST AREA.
MOIST ASCENT ON THIS WILL HELP TO CONTINUE SNOW DURING THE DAY
FRIDAY AND WITH THE COOLING PROFILE SPREAD IT EAST SOUTHEAST
ACROSS THE FORECAST AREA. TOUGH TO SAY STILL AT THIS POINT IF ANY
OF THE SNOW ON FRI WILL BE HEAVY. THERE ARE SOME SIGNATURES OF
FORCING WITHIN THIS AREA OF DEFORMATION BUT THERE HAS BEEN LITTLE
AGREEMENT ON PLACEMENT OF THIS. DURING THE DAY FRIDAY A 2 TO 4
INCH ADDITIONAL SNOW LOOKS REASONABLE FOR CTRL AND ERN MN AND WRN
WI. AGAIN...FOR SEVERAL AREAS INCLUDING THE SOUTHEAST HALF OF THE
TWIN CITIES...THIS WILL BE THE BEST CHANCE FOR SNOW ACCUMULATION.
WINDS WILL CONTINUE ON FRI LEADING TO SOME BLOWING OF PRIMARILY
THE FALLING SNOW IN RURAL OPEN AREAS...FURTHER REDUCING
VISIBILITIES.
SNOW SHOULD WIND DOWN QUICKLY TO A MORE OF A LIGHT SNOW/SNOW
SHOWERS FRI NIGHT WITH WINDS CONTINUING INTO SAT. COLD AIR
ADVECTION AHEAD OF A CANADIAN HIGH WILL KEEP TEMPS BELOW NORMAL
THIS WEEKEND. SOME NEAR 20 DEGREE LOWS ARE EXPECTED IN WEST CTRL
AREAS OVER THE FRESH SNOW. BEYOND...HAVE GONE EASY WITH THE WARM-
UP THROUGH MON AND INTO TUES...WITH THE LARGEST H8 TEMP
STANDARDIZED ANOMALIES ABOVE NORMAL COMING ON WEDS. 60 DEGREES OR
NEAR IT LOOKS LIKE IT SHOULD BE BACK DURING THE MIDDLE OF NEXT
WEEK.
&&
.AVIATION.../18Z TAF ISSUANCE/
NOTABLE CHANGES HAVE BEEN MADE TO THE 18Z TAFS. 12Z MODEL DATA
AND RECENT OBSERVATIONS CONTINUED TO INDICATE THE POTENTIAL FOR A
PROLONGED PERIOD OF A RAIN...SNOW...AND EVEN LIGHT ICE
PELLETS...ACROSS MUCH OF CENTRAL MN AND WEST CENTRAL WI THIS
AFTERNOON AND EVENING...MAINLY AT KMSP/KEAU/KRNH...WHERE THE
PRECIPITATION TYPE MAY NOT TRANSITION TO PURELY SNOW UNTIL CLOSER
TO DAYBREAK FRIDAY. HOWEVER...FOLLOWING A BRIEF RAIN/SNOW MIX THIS
AFTERNOON...ALL SNOW SHOULD DOMINATE KAXN/KRWF/KSTC THIS EVENING
AND TONIGHT...WHERE REDUCTIONS OF CEILINGS/VISIBILITIES INTO THE
IFR/LIFR CATEGORIES WILL BE POSSIBLE MAINLY BETWEEN 02Z AND 12Z.
AT KMSP/KRNH/KEAU...MAINLY MVFR CONDITIONS ARE EXPECTED UNTIL LATE
TONIGHT.
STRONG NORTHEASTERLY WINDS SUSTAINED AT SPEEDS OF 20 TO 30
MPH...WITH GUSTS INTO THE UPPER 30S...WILL ALSO PREVAIL THROUGH
TONIGHT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR BLUE EARTH-
FARIBAULT-FREEBORN-GOODHUE-LE SUEUR-RICE-STEELE-WASECA.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 AM CDT SATURDAY
FOR ANOKA-BENTON-CARVER-CHISAGO-DOUGLAS-HENNEPIN-ISANTI-
KANABEC-MILLE LACS-MORRISON-SIBLEY-TODD.
WINTER STORM WARNING UNTIL 7 AM CDT SATURDAY FOR CHIPPEWA-
KANDIYOHI-LAC QUI PARLE-MCLEOD-MEEKER-POPE-REDWOOD-RENVILLE-
SHERBURNE-STEARNS-STEVENS-SWIFT-WRIGHT-YELLOW MEDICINE.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM CDT
SATURDAY FOR DAKOTA-RAMSEY-SCOTT-WASHINGTON.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT SATURDAY FOR BROWN-MARTIN-
NICOLLET-WATONWAN.
WI...WINTER STORM WARNING FROM 7 PM THIS EVENING TO 7 AM CDT SATURDAY
FOR BARRON-POLK-RUSK.
&&
$$
AREA FORECAST DISCUSSION...UPDATE
NWS ALBUQUERQUE NM
815 PM MDT THU APR 10 2008
.UPDATE...UPDATED ZFP TO REMOVE MENTION OF EXPIRED HIGH WIND
WARNING. ALSO TRIMMED WINDS BACK TO REFLECT CURRENT TRENDS. MAY NEED
TO UPDATE AGAIN BEFORE 10 PM AS 18Z GFS AND LATEST NAM SUGGEST THERE
MAY BE SOME ADDITIONAL SNOW ACCUMULATIONS OVER THE
NORTHCENTRAL/NORTHEAST IF NOT TONIGHT THEN FRIDAY INTO SATURDAY. GFS
WAS HITTING IT HARDER THAN EARLIER INDICATED AND MAY NEED TO
CONSIDER ADVISORY AT SOME POINT.
&&
.PREV DISCUSSION 247 PM MDT THU APR 10 2008...
20Z SURFACE ANALYSIS SHOWS AN INTENSE PRESSURE GRADIENT ACROSS NM
WITH 995MB NEAR KTCC AND 1009MB NEAR KGUP. LATEST WATER VAPOR LOOP
SHOWS A NEGATIVELY TILTED TROUGH OVER THE CENTRAL PLAINS STATES AND
A POWERFUL DRY SLOT SURGING ENE ACROSS E NM/TX/OK/AND THE MS RIVER
VALLEY. 400-250MB AIRCRAFT WIND PLOT SHOWS A 110-130 KNOT JET AXIS
STATIONARY OVER THE CENTRAL ROCKIES FEEDING INTO THE BASE OF THE
TROUGH OVER NM. SEVERAL LOCATIONS ACROSS THE EASTERN PLAINS HAVE
EXCEEDED HIGH WIND WARNING THRESHOLDS THIS AFTERNOON WITH GREATER
THAN 60 MPH WIND GUSTS REPORTED NEAR TUCUMCARI...ROSWELL...CLINES
CORNERS...CANNON AFB...RUIDOSO...GRADY...AND FORT SUMNER. FARTHER
TO THE WEST CLOUD COVER BENEATH THE UPPER COLD POOL HAS LIMITED
MIXING TODAY WITH LOCATIONS WEST OF THE CENTRAL MTNS STRUGGLING
TO HIT CRITERIA. WILL CANCEL WIND ADV FOR THE WEST AND CONTINUE
WIND WARNING THRU 8 PM IN THE EAST. THE SURFACE FRONTAL BOUNDARY
MOVING SOUTH JUST NORTH OF KTCC WILL ALLOW DECOUPLING OF SFC WINDS
WITH STRONG MID LEVEL GRADIENT TO EASE HIGH WIND HAZARD FROM NORTH
TO SOUTH. HOWEVER...ADVISORY WINDS ARE STILL LIKELY ALONG AND JUST
BEHIND THE FRONT.
NAM12/GFS40 BUFKIT PROFILES INDICATE ATMOSPHERE WILL DECOUPLE
OVERNIGHT ALLOWING FOR INVERSIONS TO DEVELOP IN THE CENTRAL AND
WESTERN VALLEYS. THIS WILL BRING TEMPS BELOW FREEZING IN MANY
AREAS THAT HAVE NOT SEEN A FREEZE SINCE THE MIDDLE OF MARCH. THOSE
WITH TENDER VEGETATION OUTDOORS SHOULD BRING THEM INDOORS FOR AT
LEAST THE NEXT SEVERAL NIGHTS. MODEL SUITE IN EXCELLENT AGREEMENT
THAT ANOTHER VORT MAX WILL SHIFT SOUTH INTO THE BASE OF THE TROUGH
SATURDAY AFTERNOON WITH MORE CLOUD COVER AND MOUNTAIN SNOW SHOWERS
ESPECIALLY ALONG THE SANGRE DE CRISTOS. RAISED POPS TO HIGH CHANCE
FOR THE EAST SLOPES INTO SATURDAY NIGHT. ANOTHER COUPLE INCHES OF
SNOW IS POSSIBLE IN THESE AREAS THROUGH SUNDAY MORNING. LOWERED
TEMPS ACROSS THE BOARD TO REFLECT CONTINUED NORTHERLY FLOW THRU
SUNDAY.
MODERATING TREND BEGINS SUNDAY AS A MODERATE RIDGE BUILDS OVER THE
DESERT SW THROUGH THE MIDDLE OF NEXT WEEK. THE NEXT DISTURBANCE
APPROACHES THURSDAY WITH WINDY AND DRY PATTERN CREATING FIRE WX
HAZARDS ONCE AGAIN TUESDAY AND WEDNESDAY.
GUYER
&&
.AVIATION...
WINDS WILL GRADUALLY DECREASE THROUGH THE REST OF THE AFTERNOON INTO
THE EARLY EVENING. THE STRONGEST WINDS WILL BE ASSOCIATED WITH A
FRONTAL PASSAGE THROUGH THE NEXT FEW HOURS ACROSS THE EASTERN PLAINS
AND PORTIONS OF THE CENTRAL MOUNTAINS. ISOLATED SNOW SHOWERS WILL
ALSO COME TO AN END ACROSS THE MAJORITY OF THE AREA AS THE SUN
GOES DOWN. RESIDUAL MVFR CONDITIONS WILL REMAIN A POSSIBILITY
ACROSS FAR NORTHEAST PORTIONS OF THE FORECAST AREA THROUGH THE
OVERNIGHT.
50
NEXT AVIATION DISCUSSION SCHEDULED FOR 09Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 26 51 22 59 / 0 5 0 0
GALLUP.......................... 18 53 11 62 / 0 0 0 0
GRANTS.......................... 19 54 14 61 / 0 0 0 0
GLENWOOD........................ 25 66 29 73 / 0 0 0 0
CHAMA........................... 13 36 10 42 / 10 20 5 5
LOS ALAMOS...................... 23 44 19 50 / 5 10 10 5
RED RIVER....................... 15 32 10 35 / 20 40 30 10
TAOS............................ 19 43 17 50 / 10 20 20 5
SANTA FE........................ 24 44 22 51 / 5 10 10 5
SANTA FE AIRPORT................ 25 47 24 54 / 0 5 10 5
ESPANOLA........................ 25 50 20 58 / 5 0 10 5
ALBUQUERQUE HEIGHTS............. 30 56 30 60 / 0 5 5 0
ALBUQUERQUE VALLEY.............. 25 57 28 63 / 0 5 5 0
ALBUQUERQUE FOOTHILLS........... 27 53 28 60 / 0 5 5 0
ALBUQUERQUE WEST MESA........... 27 57 29 62 / 0 5 5 0
SOCORRO......................... 28 67 30 65 / 0 0 0 0
SANDIA PARK/CEDAR CREST......... 21 46 19 56 / 0 10 10 10
MORIARTY/ESTANCIA............... 27 52 25 56 / 0 5 10 5
CARRIZOZO....................... 30 61 29 59 / 0 0 0 0
RUIDOSO......................... 28 52 25 49 / 0 0 0 5
RATON........................... 23 43 21 52 / 20 30 20 0
LAS VEGAS....................... 25 45 20 51 / 0 20 20 5
ROY............................. 27 47 27 53 / 10 40 10 5
CLAYTON......................... 28 49 29 54 / 20 20 5 5
SANTA ROSA...................... 31 60 30 61 / 0 0 20 5
TUCUMCARI....................... 32 59 30 60 / 5 30 10 0
FORT SUMNER..................... 31 64 32 62 / 0 0 20 5
CLOVIS.......................... 32 58 32 58 / 5 10 20 5
PORTALES........................ 31 61 31 60 / 0 5 10 5
ROSWELL......................... 37 70 35 64 / 0 5 5 5
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
247 PM MDT THU APR 10 2008
.DISCUSSION...
20Z SURFACE ANALYSIS SHOWS AN INTENSE PRESSURE GRADIENT ACROSS NM
WITH 995MB NEAR KTCC AND 1009MB NEAR KGUP. LATEST WATER VAPOR LOOP
SHOWS A NEGATIVELY TILTED TROUGH OVER THE CENTRAL PLAINS STATES AND
A POWERFUL DRY SLOT SURGING ENE ACROSS E NM/TX/OK/AND THE MS RIVER
VALLEY. 400-250MB AIRCRAFT WIND PLOT SHOWS A 110-130 KNOT JET AXIS
STATIONARY OVER THE CENTRAL ROCKIES FEEDING INTO THE BASE OF THE
TROUGH OVER NM. SEVERAL LOCATIONS ACROSS THE EASTERN PLAINS HAVE
EXCEEDED HIGH WIND WARNING THRESHOLDS THIS AFTERNOON WITH GREATER
THAN 60 MPH WIND GUSTS REPORTED NEAR TUCUMCARI...ROSWELL...CLINES
CORNERS...CANNON AFB...RUIDOSO...GRADY...AND FORT SUMNER. FARTHER
TO THE WEST CLOUD COVER BENEATH THE UPPER COLD POOL HAS LIMITED
MIXING TODAY WITH LOCATIONS WEST OF THE CENRTRAL MTNS STRUGGLING
TO HIT CRITERIA. WILL CANCEL WIND ADV FOR THE WEST AND CONTINUE
WIND WARNING THRU 8 PM IN THE EAST. THE SURFACE FRONTAL BOUNDARY
MOVING SOUTH JUST NORTH OF KTCC WILL ALLOW DECOUPLING OF SFC WINDS
WITH STRONG MID LEVEL GRADIENT TO EASE HIGH WIND HAZARD FROM NORTH
TO SOUTH. HOWEVER...ADVISORY WINDS ARE STILL LIKELY ALONG AND JUST
BEHIND THE FRONT.
NAM12/GFS40 BUFKIT PROFILES INDICATE ATMOSPHERE WILL DECOUPLE
OVERNIGHT ALLOWING FOR INVERSIONS TO DEVELOP IN THE CENTRAL AND
WESTERN VALLEYS. THIS WILL BRING TEMPS BELOW FREEZING IN MANY
AREAS THAT HAVE NOT SEEN A FREEZE SINCE THE MIDDLE OF MARCH. THOSE
WITH TENDER VEGETATION OUTDOORS SHOULD BRING THEM INDOORS FOR AT
LEAST THE NEXT SEVERAL NIGHTS. MODEL SUITE IN EXCELLENT AGREEMENT
THAT ANOTHER VORT MAX WILL SHIFT SOUTH INTO THE BASE OF THE TROUGH
SATURDAY AFTERNOON WITH MORE CLOUD COVER AND MOUNTAIN SNOW SHOWERS
ESPECIALLY ALONG THE SANGRE DE CRISTOS. RAISED POPS TO HIGH CHANCE
FOR THE EAST SLOPES INTO SATURDAY NIGHT. ANOTHER COUPLE INCHES OF
SNOW IS POSSIBLE IN THESE AREAS THROUGH SUNDAY MORNING. LOWERED
TEMPS ACROSS THE BOARD TO REFLECT CONTINUED NORTHERLY FLOW THRU
SUNDAY.
MODERATING TREND BEGINS SUNDAY AS A MODERATE RIDGE BUILDS OVER THE
DESERT SW THROUGH THE MIDDLE OF NEXT WEEK. THE NEXT DISTURBANCE
APPROACHES THURSDAY WITH WINDY AND DRY PATTERN CREATING FIRE WX
HAZARDS ONCE AGAIN TUESDAY AND WEDNESDAY.
GUYER
&&
.AVIATION...
WINDS WILL GRADUALLY DECREASE THROUGH THE REST OF THE AFTERNOON INTO
THE EARLY EVENING. THE STRONGEST WINDS WILL BE ASSOCIATED WITH A
FRONTAL PASSAGE THROUGH THE NEXT FEW HOURS ACROSS THE EASTERN PLAINS
AND PORTIONS OF THE CENTRAL MOUNTAINS. ISOLATED SNOW SHOWERS WILL
ALSO COME TO AN END ACROSS THE MAJORITY OF THE AREA AS THE SUN
GOES DOWN. RESIDUAL MVFR CONDITIONS WILL REMAIN A POSSIBILITY
ACROSS FAR NORTHEAST PORTIONS OF THE FORECAST AREA THROUGH THE
OVERNIGHT.
50
NEXT AVIATION DISCUSSION SCHEDULED FOR 09Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 26 51 22 59 / 0 5 0 0
GALLUP.......................... 18 53 11 62 / 0 0 0 0
GRANTS.......................... 19 54 14 61 / 0 0 0 0
GLENWOOD........................ 25 66 29 73 / 0 0 0 0
CHAMA........................... 13 36 10 42 / 10 20 5 5
LOS ALAMOS...................... 23 44 19 50 / 5 10 10 5
RED RIVER....................... 15 32 10 35 / 20 40 30 10
TAOS............................ 19 43 17 50 / 10 20 20 5
SANTA FE........................ 24 44 22 51 / 5 10 10 5
SANTA FE AIRPORT................ 25 47 24 54 / 0 5 10 5
ESPANOLA........................ 25 50 20 58 / 5 0 10 5
ALBUQUERQUE HEIGHTS............. 30 56 30 60 / 0 5 5 0
ALBUQUERQUE VALLEY.............. 25 57 28 63 / 0 5 5 0
ALBUQUERQUE FOOTHILLS........... 27 53 28 60 / 0 5 5 0
ALBUQUERQUE WEST MESA........... 27 57 29 62 / 0 5 5 0
SOCORRO......................... 28 67 30 65 / 0 0 0 0
SANDIA PARK/CEDAR CREST......... 21 46 19 56 / 0 10 10 10
MORIARTY/ESTANCIA............... 27 52 25 56 / 0 5 10 5
CARRIZOZO....................... 30 61 29 59 / 0 0 0 0
RUIDOSO......................... 28 52 25 49 / 0 0 0 5
RATON........................... 23 43 21 52 / 20 30 20 0
LAS VEGAS....................... 25 45 20 51 / 0 20 20 5
ROY............................. 27 47 27 53 / 10 40 10 5
CLAYTON......................... 28 49 29 54 / 20 20 5 5
SANTA ROSA...................... 31 60 30 61 / 0 0 20 5
TUCUMCARI....................... 32 59 30 60 / 5 30 10 0
FORT SUMNER..................... 31 64 32 62 / 0 0 20 5
CLOVIS.......................... 32 58 32 58 / 5 10 20 5
PORTALES........................ 31 61 31 60 / 0 5 10 5
ROSWELL......................... 37 70 35 64 / 0 5 5 5
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 8 PM MDT THIS EVENING FOR THE FOLLOWING
ZONES...NMZ010>013-016>021-026.
RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR THE FOLLOWING
ZONES...NMZ108.
&&
$$
GUYER/50
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
1041 AM CDT WED APR 9 2008
.UPDATE...
BIG ISSUE TODAY IS LOW CLOUDS WHICH MOVED QUICKLY WESTWARD PRIOR
TO SUNRISE FROM BJI AREA TO GFK BY 12Z AND WHEN/IF THEY WILL
BREAKUP. EAST-SOUTHEAST FLOW AT 925 MB REMAINS PRETTY LIGHT THRU
MIDDAY AND THEN INCREASES SLIGHTLY THIS AFTN AS SFC RIDGE/925 MB
RIDGE NR A INL-MSP LINE MOVES EAST. WRN EGDE OF LOW CLOUDS FROM
WADENA TO DTL TO GFK-CAVALIER ND HAS STOPPED MOVING WEST AND NOW
WAITING TO SEE HOW THE SUN ABOVE THE CLOUD DECK HELPS BURN OFF THE
CLOUDS BELOW. TAMDAR SOUNDINGS AVBL ONLY INDICATE TEMP PROFILE
ATTM BUT THEY DO SHOW GOOD INVERSION WITH EASTERLY FLOW BENEATH
INVERSION THAT IS BASED NEAR 850 MB.
FOR THE GRIDDS...DID INCREASE SKY COVER AND LOWER TEMPS IN THE
SHORT TERM THRU MIDDAY THEN TRIED TO DECREASE SKY AND HAVE TEMPS
RISE AFTER 18Z. DID CUT BACK SLIGHTLY ON HIGH TEMPS THIS AFTN BUT
WHEN ANY SUN BREAKS THROUGH IT WILL NOT LONG TO HEAT OUT.
OTHERWISE FOR THE REST OF THE AREA LOOKS PRETTY SUNNY FARGO-DVL
AREA WITH SOME INCREASE IN MID CLOUDS EXPECTED THIS AFTN.
&&
.PREV DISCUSSION... /ISSUED 423 AM CDT WED APR 9 2008/
DISCUSSION...
MAIN FORECAST CHALLENGE IS PRECIPITATION. WHEN LOOKING AT THE LATEST
SURFACE ANALYSIS...A HIGH PRESSURE RIDGE EXTENDING THROUGH E ND AND
MN. WHEN COMPARING THE MODELS...MODELS CONTINUE TO HAVE DIFFERENCES
ON TIMING AND TRACK OF NEXT LOW PRESSURE SYSTEM...WITH THE GFS THE
MOST PROGRESSIVE AND THE FARTHEST NORTH...THE NAM THE FARTHEST
SOUTH...AND THE ECMWF AND SLOWEST AND THE COMPROMISE ON THE TRACK.
THUS...LEANED TOWARD THE GFS AS THE WORST CASE SCENARIO FOR AREAL
COVERAGE OF POPS AND ALSO BLENDED WITH THE ECMWF. THE HIGH PRESSURE
RIDGE WILL DOMINATE THE WEATHER TODAY AND TONIGHT...SO KEPT TEMPS
VERY SIMILAR TO YESTERDAY WITH NO PCPN EXPECTED.
E FLOW SETS UP OVER THE AREA AS THE NEXT LOW PRESSURE SYSTEM MOVES
OUT OF THE ROCKIES INTO THE CENTRAL PLAINS...BY THU MORNING. WITH A
SIMILAR SET UP AS THE LAST SYSTEM DEVELOPING...DRY E-NE FLOW IS
EXPECTED TO LIMIT THE N PUSH OF MOISTURE AND PCPN...AT LEAST FOR A
WHILE. THUS...NOT EXPECTING ANYTHING SIGNIFICANT TO GET GOING FOR
THE AREA UNTIL AT LEAST 00Z FRI. ALTHOUGH SE ND AND WC MN
REMAIN IN THE FAVORABLE ZONE FOR SIGNIFICANT SNOWFALL ACCUMULATION
ON THE GFS...WOULD LIKE TO SEE A LITTLE BETTER MODEL CONTINUITY
BEFORE ISSUING A WINTER STORM WATCH...SO WILL WAIT AND LET THE DAY
SHIFT TAKE ANOTHER LOOK.
THE LOW PRESSURE SYSTEM IS EXPECTED TO MOVE E OF THE AREA ON
SAT...WITH THE POTENTIAL FOR SNOWFALL THEN COMING TO AN END AS
ANOTHER HIGH PRESSURE SYSTEM BUILDS IN FOR THE REMAINDER OF THE
WEEKEND AND THE EARLY PART OF NEXT WEEK.
AVIATION...
CI AND AC WILL PRIMARILY DOMINATE THE WEATHER IN E ND THIS
MORNING...WITH AN IFR STRATUS DECK OVER MUCH OF NW AND WC MN. SOME
FOG IS ALSO POSSIBLE UNDER THE STRATUS DECK INTO THE EARLY MORNING
HOURS WITH MVFR VSBYS POSSIBLE. OTHERWISE...WINDS TO REMAIN LESS
THAN 10 KTS THROUGH THE DAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
RIDDLE
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
950 PM CDT THU APR 10 2008
.UPDATE...GOING TO BACK LINCOLN AND LANGLADE DOWN TO A WW.Y. NOT
TOTALLY SOLD ON THAT EITHER...BUT HATE TO OVERCORRECT AND START A
FLIP-FLOP. WL BE SLASHING TOTALS QUITE A BIT FOR THAT AREA...AS
WELL AS FOR N OCONTO AND S MARINETTE. EVEN AUW/CWA WITH HIGH RADAR
RETURNS AND TS IN THE OBS HOLDING AT ALL RAIN. WARM AIR MUST BE
WORKING NWD ALOFT. SFC DWPTS IN THE N STILL SUB FREEZING...BUT
THAT WON/T AFFECT WARMING IN 850-750 MB LAYER. THAT COULD LEAD TO
MORE OF A SLEET SOUNDING THOUGH.
SKOWRONSKI
&&
.PREV DISCUSSION...ISSUED AT 913 PM CDT THU APR 10 2008...
UPDATE...GETTING VERY CONCERNED OVER HEADLINES FOR N-C WI. AREAS
NEAR THE UPPER MICHIGAN BORDER PROBABLY STILL OKAY...THOUGH
WONDERING IF SNOW TOTALS FOR TONIGHT ARE TOO HIGH. THE SOUTHERN
END OF THE WARNING COULD BE A REAL PROBLEM. 00Z RUC/NAM AND 18Z GFS
ALL SHOW ENOUGH WARM AIR DRIVING INTO THE AREA BTWN 850-750 MB TO
AT LEAST GET THEM OVER TO SLEET...AND POSSIBLY TO MAINLY RAIN.
SFC OBS SEEM TO BE CONFIRMING THE NWD PROGRESS OF THE WARM
AIR...THOUGH WITH PCPN INTENSITY WANING IT/S TOUGH TO TELL WHAT
WILL HAPPEN WHEN BETTER LIFT GETS BACK INTO THAT AREA. JUST HAD
SOME SLEET MIXED IN WITH HEAVIER BAND COMING OVER THE OFFICE.
WL MONITOR A BIT MORE AND MAKE A DECISION BEFORE 1000 PM.
DISCUSSION ISSUED AT 602 PM CDT THU APR 10 2008...
UPDATE...PCPN SURGING NWD ACRS THE AREA. MUCH LIKE A COUPLE
NIGHTS AGO...ENUF COOLING WITH THE HEAVIEST PCPN TO CHG IT OVER TO
ALL SNOW. UPDATED GRIDS TO HIT SNOW A BIT HARDER IN CENTRAL
WI...WHERE A FEW SITES WERE MODERATE/HEAVY. WEBCAMS INDICATED ONLY
SOME SLUSHY ACCUMULATIONS SO FAR. RADAR RETURNS DECRG ACRS THAT
AREA...SO MAY SEE MORE OF A MIX IN THE NEXT HR OR TWO.
SITN ACRS THE N VERY MUCH UP IN THE AIR. THE 18Z NAM WAS THE ONLY
MODEL WHICH HAD FCST SOUNDINGS COLD ENOUGH TO SUPPORT THE SNOW
OBSERVED AT AUW LATE THIS AFTN. BUT IT WARMED THINGS
CONSIDERABLY...AND SUGGESTED RHI MIGHT BE MAINLY RAIN OR SLEET
MUCH OF THE NGT. THAT WOULD BE CONSISTENT WITH DEEP SLY FLOW ABV
850 MB. ON THE OTHER HAND...RECENT AIRCRAFT SOUNDINGS FM RHI
INDICATED A SOUNDING COLD ENUF FOR SNOW RIGHT NOW. ALSO...VERY DRY
AIR HAD WORKED INTO THE N AT LOW-LEVELS...WITH SFC DWPTS PLUNGING
INTO THE TEENS ACRS VILAS COUNTY. THAT SETS THE STAGE FOR SIG
EVAPORATIVE COOLING AT LOW LEVELS...AND EVEN RAISES THE
POSSIBILITY OF GETTING SOME ZR. GIVEN THE CONFICTING SIGNS...IT/S
GOING TO BE A WAIT AND SEE FOR THE FAR NORTH THIS EVENING.
LOOKING AT THE BIGGER PICTURE...A BIT CONCERNED SYSTEM ALREADY
OCCLUDED AND MATURE LOOKING. HAVE TO WONDER WHERE THE MOISTURE WL
COME FROM FOR SIG PCPN FOR THE NEXT SEVERAL FCST PERIODS. BUT
HAVE ENOUGH SHORT-TERM ISSUES TO DEAL WITH FOR NOW.
DISCUSSION ISSUED AT 432 PM CDT THU APR 10 2008...
SHORT TERM...SURGE OF INITIAL MOISTURE WORKING NORTH THROUGH
AREA ASSOCIATED WITH STRONG ISENTROPIC LIFT...JET PUSHING NORTH. SLOWLY
SATURATING DRY AIR MASS SEEN ON MORNING SOUNDINGS...RAIN IN SOUTH MIXING
WITH SLEET/SNOW INITIALLY GIVEN EVAPORATIVE COOLING...SHOULD BE
MAINLY SNOW AS WORKS NORTH AGAINST DRY AIR. SOME CONCERN THAT
MOISTURE BEING SQUEEZED BETWEEN HIGH TO NORTH AND DRY SLOT TO
SOUTH WILL LIMIT AMOUNTS...THOUGH STARTING TO FILL IN TO THE
SOUTH. SNOW AMOUNTS ALSO COMPLICATED BY WARM BOUNDARY LAYER TEMPS
TODAY WITH HIGHS AROUND 40 TO THE NORTH. GIVEN QUICKER MOVEMENT OF
PCPN INTO AREA THAN EARLIER FORECAST...PUSHED FORWARD WARNING TIME
TO 00Z. ALL MODELS PUSHING WARM AIR NORTH THROUGH THE
NIGHT...FOLLOWED SREF 850 TEMPS FOR PLACING MIX. OPERATIONAL RUNS
WARMER...THUS STILL SOME CONCERN HOW FAR NORTH TO BRING RAIN/MIX.
BELIEVE TOO WARM FOR WARNING SNOWS EAST...THOUGH MIX STILL WARRANT ADVISORY.
LULL IN ACTION FOR A TIME FRI MORNING AS BEST FORCING LIFTS NORTH
INTO UPPER MI. DYNAMICS WITH UPPER LOW MOVE INTO AREA DURING
AFTERNOON. KEPT WARNING TIMING GOING AS IS.
LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
12Z MODELS CONTINUE TO FOCUS ON HEAVIEST PRECIPITATION OVER THE
FAR NORTHEAST. HAVE TRENDED HIGHEST PRECIPITATION TOTALS IN THIS
AREA ALONG WITH THE HEAVIEST SNOWFALL ACCUMULATIONS OVER THE FAR
NORTH. PRECIPITATION TYPE WILL STILL BE AN ISSUE DURING THE EVENING
HOURS ALONG THE BAY ACROSS MARINETTE AND OCONTO COUNTIES SOUTHWARD
TO GREEN BAY AND OSHKOSH EAST TO THE LAKE. SNOWFALL TOTALS SHOULD
RANGE FROM 2 TO 4 INCHES ACROSS VILAS AND ONEIDA COUNTIES WITH
3 TO 5 INCHES OVER FLORENCE AND FOREST COUNTIES. SNOWFALL TOTALS
SHOULD RANGE FROM 1 TO 3 INCHES FROM WAUSAU TO WISCONSIN RAPIDS
TO STEVENS POINT AREA. ACROSS GREEN BAY...OSHKOSH AND THE FOX CITIES
CAN EXPECT AN INCH OR TWO OF SNOW WHILE LOCATIONS ALONG THE LAKE
MAY SEE AROUND AN INCH OR LESS.
UPPER LOW SLOWLY MOVES EAST ON SATURDAY. CYCLONIC FLOW AND WEAK
DISTURBANCES ROTATING AROUND UPPER LOW WILL BRING LIKELY CHANCES
FOR SNOW. AN ADDITIONAL INCH OR TWO OF SNOW IS POSSIBLE WITH THE
HEAVIER SNOW SHOWERS. CONTINUED CHANCES FOR SNOW SHOWERS SATURDAY
NIGHT WITH HIGHEST CHANCES OVER THE EAST. ON SUNDAY...ADDED A
CHANCE OF FLURRIES OVER THE FAR EAST PER COORDINATION WITH
MILWAUKEE AND CHICAGO AS ABUNDANT LOW LEVEL MOISTURE REMAINS IN
PLACE.
TRANQUIL PERIOD EXPECTED SUNDAY NIGHT AND MONDAY. NEXT SYSTEM WILL
AFFECT THE AREA LATE TUESDAY NIGHT AND WEDNESDAY. BASED ON THE NEWEST
MODEL RUNS...HAVE RAISED TEMPERATURES UP SEVERAL DEGREES. MAY NEED
TO RAISE THEM EVEN MORE OVER THE NEXT FEW DAYS. NEW 12Z ECMWF HAS
+16C AT 850MB NEXT WEDNESDAY AT 12Z WHILE GFS A MUCH MORE MODEL
+9C.
AVIATION...IFR TO MVFR WEATHER EXPECTED THROUGH NIGHT AS STORM
SYSTEM MOVES INTO THE AREA. STRONG EAST WINDS COULD MAKE FOR USE OF
NORTH/SOUTH RUNWAYS DIFFICULT THROUGH THE NIGHT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 7 AM CDT SATURDAY
WIZ005-010>013-
WINTER WEATHER ADVISORY UNTIL 7 AM CDT SATURDAY
WIZ018-019-021-073-
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
913 PM CDT THU APR 10 2008
.UPDATE...GETTING VERY CONCERNED OVER HEADLINES FOR N-C WI. AREAS
NEAR THE UPPER MICHIGAN BORDER PROBABLY STILL OKAY...THOUGH
WONDERING IF SNOW TOTALS FOR TONIGHT ARE TOO HIGH. THE SOUTHERN
END OF THE WARNING COULD BE A REAL PROBLEM. 00Z RUC/NAM AND 18Z GFS
ALL SHOW ENOUGH WARM AIR DRIVING INTO THE AREA BTWN 850-750 MB TO
AT LEAST GET THEM OVER TO SLEET...AND POSSIBLY TO MAINLY RAIN.
SFC OBS SEEM TO BE CONFIRMING THE NWD PROGRESS OF THE WARM
AIR...THOUGH WITH PCPN INTENSITY WANING IT/S TOUGH TO TELL WHAT
WILL HAPPEN WHEN BETTER LIFT GETS BACK INTO THAT AREA. JUST HAD
SOME SLEET MIXED IN WITH HEAVIER BAND COMING OVER THE OFFICE.
WL MONITOR A BIT MORE AND MAKE A DECISION BEFORE 1000 PM.
SKOWRONSKI
&&
.PREV DISCUSSION...ISSUED AT 602 PM CDT THU APR 10 2008...
UPDATE...PCPN SURGING NWD ACRS THE AREA. MUCH LIKE A COUPLE
NIGHTS AGO...ENUF COOLING WITH THE HEAVIEST PCPN TO CHG IT OVER TO
ALL SNOW. UPDATED GRIDS TO HIT SNOW A BIT HARDER IN CENTRAL
WI...WHERE A FEW SITES WERE MODERATE/HEAVY. WEBCAMS INDICATED ONLY
SOME SLUSHY ACCUMULATIONS SO FAR. RADAR RETURNS DECRG ACRS THAT
AREA...SO MAY SEE MORE OF A MIX IN THE NEXT HR OR TWO.
SITN ACRS THE N VERY MUCH UP IN THE AIR. THE 18Z NAM WAS THE ONLY
MODEL WHICH HAD FCST SOUNDINGS COLD ENOUGH TO SUPPORT THE SNOW
OBSERVED AT AUW LATE THIS AFTN. BUT IT WARMED THINGS
CONSIDERABLY...AND SUGGESTED RHI MIGHT BE MAINLY RAIN OR SLEET
MUCH OF THE NGT. THAT WOULD BE CONSISTENT WITH DEEP SLY FLOW ABV
850 MB. ON THE OTHER HAND...RECENT AIRCRAFT SOUNDINGS FM RHI
INDICATED A SOUNDING COLD ENUF FOR SNOW RIGHT NOW. ALSO...VERY DRY
AIR HAD WORKED INTO THE N AT LOW-LEVELS...WITH SFC DWPTS PLUNGING
INTO THE TEENS ACRS VILAS COUNTY. THAT SETS THE STAGE FOR SIG
EVAPORATIVE COOLING AT LOW LEVELS...AND EVEN RAISES THE
POSSIBILITY OF GETTING SOME ZR. GIVEN THE CONFICTING SIGNS...IT/S
GOING TO BE A WAIT AND SEE FOR THE FAR NORTH THIS EVENING.
LOOKING AT THE BIGGER PICTURE...A BIT CONCERNED SYSTEM ALREADY
OCCLUDED AND MATURE LOOKING. HAVE TO WONDER WHERE THE MOISTURE WL
COME FROM FOR SIG PCPN FOR THE NEXT SEVERAL FCST PERIODS. BUT
HAVE ENOUGH SHORT-TERM ISSUES TO DEAL WITH FOR NOW.
DISCUSSION ISSUED AT 432 PM CDT THU APR 10 2008...
SHORT TERM...SURGE OF INITIAL MOISTURE WORKING NORTH THROUGH
AREA ASSOCIATED WITH STRONG ISENTROPIC LIFT...JET PUSHING NORTH. SLOWLY
SATURATING DRY AIR MASS SEEN ON MORNING SOUNDINGS...RAIN IN SOUTH MIXING
WITH SLEET/SNOW INITIALLY GIVEN EVAPORATIVE COOLING...SHOULD BE
MAINLY SNOW AS WORKS NORTH AGAINST DRY AIR. SOME CONCERN THAT
MOISTURE BEING SQUEEZED BETWEEN HIGH TO NORTH AND DRY SLOT TO
SOUTH WILL LIMIT AMOUNTS...THOUGH STARTING TO FILL IN TO THE
SOUTH. SNOW AMOUNTS ALSO COMPLICATED BY WARM BOUNDARY LAYER TEMPS
TODAY WITH HIGHS AROUND 40 TO THE NORTH. GIVEN QUICKER MOVEMENT OF
PCPN INTO AREA THAN EARLIER FORECAST...PUSHED FORWARD WARNING TIME
TO 00Z. ALL MODELS PUSHING WARM AIR NORTH THROUGH THE
NIGHT...FOLLOWED SREF 850 TEMPS FOR PLACING MIX. OPERATIONAL RUNS
WARMER...THUS STILL SOME CONCERN HOW FAR NORTH TO BRING RAIN/MIX.
BELIEVE TOO WARM FOR WARNING SNOWS EAST...THOUGH MIX STILL WARRANT ADVISORY.
LULL IN ACTION FOR A TIME FRI MORNING AS BEST FORCING LIFTS NORTH
INTO UPPER MI. DYNAMICS WITH UPPER LOW MOVE INTO AREA DURING
AFTERNOON. KEPT WARNING TIMING GOING AS IS.
LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
12Z MODELS CONTINUE TO FOCUS ON HEAVIEST PRECIPITATION OVER THE
FAR NORTHEAST. HAVE TRENDED HIGHEST PRECIPITATION TOTALS IN THIS
AREA ALONG WITH THE HEAVIEST SNOWFALL ACCUMULATIONS OVER THE FAR
NORTH. PRECIPITATION TYPE WILL STILL BE AN ISSUE DURING THE EVENING
HOURS ALONG THE BAY ACROSS MARINETTE AND OCONTO COUNTIES SOUTHWARD
TO GREEN BAY AND OSHKOSH EAST TO THE LAKE. SNOWFALL TOTALS SHOULD
RANGE FROM 2 TO 4 INCHES ACROSS VILAS AND ONEIDA COUNTIES WITH
3 TO 5 INCHES OVER FLORENCE AND FOREST COUNTIES. SNOWFALL TOTALS
SHOULD RANGE FROM 1 TO 3 INCHES FROM WAUSAU TO WISCONSIN RAPIDS
TO STEVENS POINT AREA. ACROSS GREEN BAY...OSHKOSH AND THE FOX CITIES
CAN EXPECT AN INCH OR TWO OF SNOW WHILE LOCATIONS ALONG THE LAKE
MAY SEE AROUND AN INCH OR LESS.
UPPER LOW SLOWLY MOVES EAST ON SATURDAY. CYCLONIC FLOW AND WEAK
DISTURBANCES ROTATING AROUND UPPER LOW WILL BRING LIKELY CHANCES
FOR SNOW. AN ADDITIONAL INCH OR TWO OF SNOW IS POSSIBLE WITH THE
HEAVIER SNOW SHOWERS. CONTINUED CHANCES FOR SNOW SHOWERS SATURDAY
NIGHT WITH HIGHEST CHANCES OVER THE EAST. ON SUNDAY...ADDED A
CHANCE OF FLURRIES OVER THE FAR EAST PER COORDINATION WITH
MILWAUKEE AND CHICAGO AS ABUNDANT LOW LEVEL MOISTURE REMAINS IN
PLACE.
TRANQUIL PERIOD EXPECTED SUNDAY NIGHT AND MONDAY. NEXT SYSTEM WILL
AFFECT THE AREA LATE TUESDAY NIGHT AND WEDNESDAY. BASED ON THE NEWEST
MODEL RUNS...HAVE RAISED TEMPERATURES UP SEVERAL DEGREES. MAY NEED
TO RAISE THEM EVEN MORE OVER THE NEXT FEW DAYS. NEW 12Z ECMWF HAS
+16C AT 850MB NEXT WEDNESDAY AT 12Z WHILE GFS A MUCH MORE MODEL
+9C.
AVIATION...IFR TO MVFR WEATHER EXPECTED THROUGH NIGHT AS STORM
SYSTEM MOVES INTO THE AREA. STRONG EAST WINDS COULD MAKE FOR USE OF
NORTH/SOUTH RUNWAYS DIFFICULT THROUGH THE NIGHT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 7 AM CDT SATURDAY FOR WIZ005-010>013-
018-019.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT SATURDAY FOR WIZ021-073.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
602 PM CDT THU APR 10 2008
.UPDATE...PCPN SURGING NWD ACRS THE AREA. MUCH LIKE A COUPLE
NIGHTS AGO...ENUF COOLING WITH THE HEAVIEST PCPN TO CHG IT OVER TO
ALL SNOW. UPDATED GRIDS TO HIT SNOW A BIT HARDER IN CENTRAL
WI...WHERE A FEW SITES WERE MODERATE/HEAVY. WEBCAMS INDICATED ONLY
SOME SLUSHY ACCUMULATIONS SO FAR. RADAR RETURNS DECRG ACRS THAT
AREA...SO MAY SEE MORE OF A MIX IN THE NEXT HR OR TWO.
SITN ACRS THE N VERY MUCH UP IN THE AIR. THE 18Z NAM WAS THE ONLY
MODEL WHICH HAD FCST SOUNDINGS COLD ENOUGH TO SUPPORT THE SNOW
OBSERVED AT AUW LATE THIS AFTN. BUT IT WARMED THINGS
CONSIDERABLY...AND SUGGESTED RHI MIGHT BE MAINLY RAIN OR SLEET
MUCH OF THE NGT. THAT WOULD BE CONSISTENT WITH DEEP SLY FLOW ABV
850 MB. ON THE OTHER HAND...RECENT AIRCRAFT SOUNDINGS FM RHI
INDICATED A SOUNDING COLD ENUF FOR SNOW RIGHT NOW. ALSO...VERY DRY
AIR HAD WORKED INTO THE N AT LOW-LEVELS...WITH SFC DWPTS PLUNGING
INTO THE TEENS ACRS VILAS COUNTY. THAT SETS THE STAGE FOR SIG
EVAPORATIVE COOLING AT LOW LEVELS...AND EVEN RAISES THE
POSSIBILITY OF GETTING SOME ZR. GIVEN THE CONFICTING SIGNS...IT/S
GOING TO BE A WAIT AND SEE FOR THE FAR NORTH THIS EVENING.
LOOKING AT THE BIGGER PICTURE...A BIT CONCERNED SYSTEM ALREADY
OCCLUDED AND MATURE LOOKING. HAVE TO WONDER WHERE THE MOISTURE WL
COME FROM FOR SIG PCPN FOR THE NEXT SEVERAL FCST PERIODS. BUT
HAVE ENOUGH SHORT-TERM ISSUES TO DEAL WITH FOR NOW.
SKOWRONSKI
&&
.PREV DISCUSSION...ISSUED AT 432 PM CDT THU APR 10 2008...
SHORT TERM...SURGE OF INITIAL MOISTURE WORKING NORTH THROUGH
AREA ASSOCIATED WITH STRONG ISENTROPIC LIFT...JET PUSHING NORTH. SLOWLY
SATURATING DRY AIR MASS SEEN ON MORNING SOUNDINGS...RAIN IN SOUTH MIXING
WITH SLEET/SNOW INITIALLY GIVEN EVAPORATIVE COOLING...SHOULD BE
MAINLY SNOW AS WORKS NORTH AGAINST DRY AIR. SOME CONCERN THAT
MOISTURE BEING SQUEEZED BETWEEN HIGH TO NORTH AND DRY SLOT TO
SOUTH WILL LIMIT AMOUNTS...THOUGH STARTING TO FILL IN TO THE
SOUTH. SNOW AMOUNTS ALSO COMPLICATED BY WARM BOUNDARY LAYER TEMPS
TODAY WITH HIGHS AROUND 40 TO THE NORTH. GIVEN QUICKER MOVEMENT OF
PCPN INTO AREA THAN EARLIER FORECAST...PUSHED FORWARD WARNING TIME
TO 00Z. ALL MODELS PUSHING WARM AIR NORTH THROUGH THE
NIGHT...FOLLOWED SREF 850 TEMPS FOR PLACING MIX. OPERATIONAL RUNS
WARMER...THUS STILL SOME CONCERN HOW FAR NORTH TO BRING RAIN/MIX.
BELIEVE TOO WARM FOR WARNING SNOWS EAST...THOUGH MIX STILL WARRANT ADVISORY.
LULL IN ACTION FOR A TIME FRI MORNING AS BEST FORCING LIFTS NORTH
INTO UPPER MI. DYNAMICS WITH UPPER LOW MOVE INTO AREA DURING
AFTERNOON. KEPT WARNING TIMING GOING AS IS.
LONG TERM...FRIDAY NIGHT THROUGH THURSDAY
12Z MODELS CONTINUE TO FOCUS ON HEAVIEST PRECIPITATION OVER THE
FAR NORTHEAST. HAVE TRENDED HIGHEST PRECIPITATION TOTALS IN THIS
AREA ALONG WITH THE HEAVIEST SNOWFALL ACCUMULATIONS OVER THE FAR
NORTH. PRECIPITATION TYPE WILL STILL BE AN ISSUE DURING THE EVENING
HOURS ALONG THE BAY ACROSS MARINETTE AND OCONTO COUNTIES SOUTHWARD
TO GREEN BAY AND OSHKOSH EAST TO THE LAKE. SNOWFALL TOTALS SHOULD
RANGE FROM 2 TO 4 INCHES ACROSS VILAS AND ONEIDA COUNTIES WITH
3 TO 5 INCHES OVER FLORENCE AND FOREST COUNTIES. SNOWFALL TOTALS
SHOULD RANGE FROM 1 TO 3 INCHES FROM WAUSAU TO WISCONSIN RAPIDS
TO STEVENS POINT AREA. ACROSS GREEN BAY...OSHKOSH AND THE FOX CITIES
CAN EXPECT AN INCH OR TWO OF SNOW WHILE LOCATIONS ALONG THE LAKE
MAY SEE AROUND AN INCH OR LESS.
UPPER LOW SLOWLY MOVES EAST ON SATURDAY. CYCLONIC FLOW AND WEAK
DISTURBANCES ROTATING AROUND UPPER LOW WILL BRING LIKELY CHANCES
FOR SNOW. AN ADDITIONAL INCH OR TWO OF SNOW IS POSSIBLE WITH THE
HEAVIER SNOW SHOWERS. CONTINUED CHANCES FOR SNOW SHOWERS SATURDAY
NIGHT WITH HIGHEST CHANCES OVER THE EAST. ON SUNDAY...ADDED A
CHANCE OF FLURRIES OVER THE FAR EAST PER COORDINATION WITH
MILWAUKEE AND CHICAGO AS ABUNDANT LOW LEVEL MOISTURE REMAINS IN
PLACE.
TRANQUIL PERIOD EXPECTED SUNDAY NIGHT AND MONDAY. NEXT SYSTEM WILL
AFFECT THE AREA LATE TUESDAY NIGHT AND WEDNESDAY. BASED ON THE NEWEST
MODEL RUNS...HAVE RAISED TEMPERATURES UP SEVERAL DEGREES. MAY NEED
TO RAISE THEM EVEN MORE OVER THE NEXT FEW DAYS. NEW 12Z ECMWF HAS
+16C AT 850MB NEXT WEDNESDAY AT 12Z WHILE GFS A MUCH MORE MODEL
+9C.
AVIATION...IFR TO MVFR WEATHER EXPECTED THROUGH NIGHT AS STORM
SYSTEM MOVES INTO THE AREA. STRONG EAST WINDS COULD MAKE FOR USE OF
NORTH/SOUTH RUNWAYS DIFFICULT THROUGH THE NIGHT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 7 AM CDT SATURDAY
WIZ005-010>013- 018-019-
WINTER WEATHER ADVISORY UNTIL 7 AM CDT SATURDAY
WIZ021-073-
&&
$$
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