Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 01/23/15
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
1045 AM MST WED JAN 21 2015
...UPDATED AVIATION DISCUSSION...
&&
.SYNOPSIS...
A SMALL LOW PRESSURE SYSTEM MOVING ACROSS THE MOHAVE DESERT AND
ARIZONA TODAY WILL LEAD TO A CHANCE OF SHOWERS OVER MAINLY NORTHERN
ARIZONA...WITH ONLY A SLIGHT CHANCE OVER THE CENTRAL ARIZONA
DESERTS. STRONG NORTHERLY WINDS WILL DEVELOP OVER THE LOWER THE
COLORADO RIVER VALLEY AND ADJACENT AREAS...LESS WIND ELSEWHERE.
BREEZY TO WINDY CONDITIONS EXPAND TO CENTRAL AND EASTERN ARIZONA
THURSDAY. ADDITIONAL COOLING CAN BE EXPECTED AS WELL. TEMPERATURES
REBOUND OVER THE WEEKEND AS HIGH PRESSURE BUILDS IN. INCREASED
CLOUDINESS AND A SLIGHT CHANCE OF SHOWERS IS POSSIBLE EARLY NEXT
WEEK.
&&
.DISCUSSION...
THE UPPER LOW WHICH BROUGHT SOME LIGHT SHOWERS TO THE LAS VEGAS AREA
LAST NIGHT IS NOW BEGINNING TO MOVE EASTWARD ACROSS WEST-CENTRAL
ARIZONA. ALTHOUGH THE LATEST 88D RADAR IMAGERY DOES SHOW SOME LIGHT
SHOWERS MOVING INTO YAVAPAI AND NORTHERN LA PAZ COUNTIES...AND EVEN
INTO EXTREME NORTHWEST MARICOPA COUNTY AT THIS TIME...A DRY SUBCLOUD
LAYER AND LIMITED PWAT VALUES (MAIN AOB 0.35 INCH) IS LIKELY KEEPING
ANYTHING MORE THAN A SPRINKLE OR LIGHT SHOWER FROM REACHING THE
GROUND AT THIS TIME. THE LATEST HRRR HI-RES RUN CONTINUES TO SHOW
THE DEVELOPMENT OF ISOLATED SPRINKLES/SHOWERS ACROSS EXTREME
NORTHERN MARICOPA COUNTY THROUGH THE REMAINDER OF THE MORNING
HOURS...AND INTO THE AFTERNOON AS WELL...WHICH IS DEPICTED WELL IN
OUR CURRENT GRIDDED FORECASTS. THE HRRR ALSO CONTINUE TO SHOW THE
DEVELOPMENT OF MORE WIDESPREAD SHOWER ACTIVITY OVER EXTREME EASTERN
MARICOPA COUNTY AND OVER SOUTHERN GILA COUNTY LATE THIS AFTERNOON
INTO THE EARLY EVENING HOURS AS THE UPPER LOW PASSES OVER THAT
REGION. ALONG WITH THE SHOWER ACTIVITY...SFC HIGH PRESSURE BUILDING
SOUTHWARD INTO THE GREAT BASIN IS STILL EXPECTED TO PRODUCE GUSTY
WINDS DOWN THE LOWER COLORADO RIVER VALLEY...WITH THE BLYTHE ASOS
ALREADY SHOWING 15 KNOT SUSTAINED WINDS...AND THE GFS MOS SHOWING
25KT SUSTAINED WINDS BY THIS AFTERNOON AT THAT SITE. HOWEVER...IT
APPEARS THAT WINDS WILL LIKELY REMAIN JUST BELOW WIND ADVISORY
CRITERIA DUE TO LIMITED AREAL AND TEMPORAL COVERAGE. AS FAR AS THE
VERY SHORT TERM IS CONCERNED...OTHER THAN SOME MINOR ADJUSTMENTS TO
THE HOURLY TEMPERATURE...DEWPOINT...AND WIND GRIDS...CURRENT GRIDDED
AND ZONE FORECASTS STILL LOOK GOOD.
&&
.PREVIOUS DISCUSSION...
TODAY THROUGH FRIDAY...
THE MAIN VORT MAX ASSOCIATED WITH THE SHORT WAVE OVER THE MOHAVE
DESERT AND ARIZONA IS CENTERED BETWEEN KINGMAN AND LAS VEGAS EARLY
THIS MORNING. RADAR ECHOES HAVE BEEN WEAK BUT WHERE THEY HAVE BEEN
STRONGEST...CLOSEST TO THE VORT MAX CENTER...SOME VERY LIGHT RAIN
HAS OCCURRED. DESPITE DECENT DYNAMICAL FORCING THE MOISTURE
AVAILABILITY IS MEAGER AS IS EVIDENT IN THE BLENDED TPW IMAGERY WITH
PWAT VALUES BARELY OVER HALF AN INCH. THE HRRR HAS BEEN HANDLING
THINGS WELL OVERNIGHT AND IT SHOWS LIGHT PRECIP TRACKING JUST NORTH
OF OUR FORECAST AREA UNTIL LATE THIS AFTERNOON WHERE IT DEPICTS
ISOLATED SHOWERS PUSHING INTO NORTHERN MARICOPA COUNTY AND SOUTHERN
GILA COUNTY. OTHER HI-RES MODELS FROM NCEP AND LOCAL SOURCES DEPICT
A SIMILAR PATTERN. THIS IS LIKELY DUE JUST ENOUGH INSTABILITY TO GET
SOME SHALLOW CONVECTION GOING...NAM BOUNDARY LAYER CAPE INDICATING
100-150 J/KG. ANTICIPATE CAPE TO BE TOO WEAK TO GET THUNDERSTORMS
GOING BUT IT WOULD NOT BE IMPOSSIBLE TO GET A STRAY LIGHTNING
STRIKE. BETTER OPPORTUNITY FOR PRECIP IN OUR FORECAST AREA WILL BE
OVER THE HIGHER TERRAIN NORTHEAST AND EAST OF PHOENIX. POPS LINGER
OVER THAT AREA TONIGHT BEFORE TAPERING OFF. WINDY CONDITIONS FROM
THE NORTH CAN BE EXPECTED OVER SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...MOST NOTICEABLY OVER THE LOWER COLORADO RIVER
VALLEY...WHERE PEAK GUSTS MAY GET CLOSE TO WIND ADVISORY
CRITERIA...LIGHTER WINDS OVER SOUTH-CENTRAL ARIZONA. ANTICIPATE SOME
COOLING TODAY AS WELL.
RIGHT BEHIND THIS FIRST SHORT WAVE A MORE VIGOROUS ONE COMES DOWN
FROM THE NORTH AND TRACKS ACROSS EASTERN ARIZONA LATE TONIGHT AND
THURSDAY MORNING. MOISTURE LOOKS TO BE TOO LIMITED FOR ANY POPS WITH
IT OVER OUR AREA. HOWEVER...IT TURN UP THE NORTHEASTERLY BREEZINESS
OVER OUR EASTERN AREAS INCLUDING PHOENIX METRO...LESS WINDY SW AZ
AND SE CAL. IT WILL ALSO INTRODUCE ADDITIONAL COOLING BRINGING HIGH
TEMPS THURSDAY INTO THE 60S ON THE LOWER DESERTS.
ANOTHER SHORT WAVE MOVES SOUTHWARD ACROSS THE FORECAST AREA FRIDAY
BUT IT IS WEAK AND THE AIR WILL BE MUCH TOO DRY FOR ANY PRECIP
THREAT. PART OF THE REASON IT IS WEAK IT DUE TO A SPLIT IN THE
NORTHERLY FLOW WHERE MORE OF THE ENERGY TRACKS WEST. IN
FACT...THERE IS GOOD MODEL AGREEMENT THAT IT WILL DEEPEN INTO A
CLOSED LOW WEST OF BAJA.
SATURDAY AND SUNDAY...
A STRONG PACIFIC RIDGE BUILDS OVER THE WESTERN STATES THIS WEEKEND
FOR A SIGNIFICANT WARMING TREND. ANTICIPATE LINGERING NORTHEASTERLY
BREEZINESS INTO EARLY NEXT WEEK. MADE SOME MINOR DOWNWARD
ADJUSTMENTS TO THE TEMPS COMPARED TO PREVIOUS FORECAST PACKAGE DUE
TO MORE CLOUDINESS ANTICIPATED.
MONDAY AND TUESDAY...
THE UPPER LOW WEST OF BAJA IS ADVERTISED TO MOVE NORTHWARD MONDAY
AND TUESDAY. WITH THE RIDGE CENTERED OVER THE INTERMOUNTAIN
WEST...THE LOW WEAKENS QUITE A BIT. HOWEVER...IT WILL HAVE A LOT OF
MOISTURE TO WORK WITH. THUS INTRODUCED SLIGHT CHANCE POPS ACROSS THE
FORECAST AREA FOR MONDAY AND TUESDAY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL.
SKIES ARE SLOWLY CLEARING WITH SOME VIRGA SHOWERS TO THE NORTHWEST
OF PHOENIX AREA TERMINALS LATE THIS MORNING. ANOTHER ROUND OF LIGHT
SHOWERS ARE POSSIBLE THIS AFTERNOON WEST OF KPHX AND CONFIDENCE IS
LOW ANYTHING WILL MATERIALIZE IN PHOENIX SO LEFT OFF MENTION OF
VCSH. WINDS WILL KEEP A NORTHERLY COMPONENT THROUGH SUNSET BEFORE
SWITCHING TO AN EASTERLY PUSH.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH.
FRONTAL PASSAGE LATE THIS MORNING HAS INCREASED WINDS ALONG THE
LOWER COLORADO RIVER VALLEY. LOOKING FOR SUSTAINED WINDS AROUND 15
KTS WITH GUSTS NEAR 30 KTS FOR A FEW HOURS THIS AFTERNOON.
CONDITIONS SHOULD REMAIN JUST BELOW WIND ADVISORY CRITERIA WITH A
FEW PERIODS THAT MAY MEET CRITERIA...WITH CONDITIONS DIMINISHING
OVERNIGHT BUT STILL AROUND 12 TO 15 KTS. MOSTLY CLEAR SKIES WILL
PREVAIL THROUGH 18Z THURSDAY.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
FRIDAY THROUGH WEDNESDAY...
FRIDAY AND SATURDAY...AFTERNOON NORTH TO NORTHEAST WIND 10 TO 20
MPH...PARTICULARLY ALONG THE COLORADO RIVER VALLEY. MOSTLY CLEAR
SKIES. MINIMUM RELATIVE HUMIDITIES IN THE 10 TO 20 PERCENT RANGE
WITH ABOVE NORMAL AFTERNOON TEMPERATURES. SUNDAY THROUGH
WEDNESDAY...CONTINUE DRY WEATHER AND LIGHT WIND. MINIMUM RELATIVE
HUMIDITIES INCREASING INTO THE 25 TO 30 PERCENT RANGE BY WEDNESDAY.
ABOVE NORMAL TEMPERATURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/AJ
AVIATION...DEWEY
FIRE WEATHER...VASQUEZ
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
905 AM MST WED JAN 21 2015
&&
.SYNOPSIS...
A SMALL LOW PRESSURE SYSTEM MOVING ACROSS THE MOHAVE DESERT AND
ARIZONA TODAY WILL LEAD TO A CHANCE OF SHOWERS OVER MAINLY NORTHERN
ARIZONA...WITH ONLY A SLIGHT CHANCE OVER THE CENTRAL ARIZONA
DESERTS. STRONG NORTHERLY WINDS WILL DEVELOP OVER THE LOWER THE
COLORADO RIVER VALLEY AND ADJACENT AREAS...LESS WIND ELSEWHERE.
BREEZY TO WINDY CONDITIONS EXPAND TO CENTRAL AND EASTERN ARIZONA
THURSDAY. ADDITIONAL COOLING CAN BE EXPECTED AS WELL. TEMPERATURES
REBOUND OVER THE WEEKEND AS HIGH PRESSURE BUILDS IN. INCREASED
CLOUDINESS AND A SLIGHT CHANCE OF SHOWERS IS POSSIBLE EARLY NEXT
WEEK.
&&
.DISCUSSION...
THE UPPER LOW WHICH BROUGHT SOME LIGHT SHOWERS TO THE LAS VEGAS AREA
LAST NIGHT IS NOW BEGINNING TO MOVE EASTWARD ACROSS WEST-CENTRAL
ARIZONA. ALTHOUGH THE LATEST 88D RADAR IMAGERY DOES SHOW SOME LIGHT
SHOWERS MOVING INTO YAVAPAI AND NORTHERN LA PAZ COUNTIES...AND EVEN
INTO EXTREME NORTHWEST MARICOPA COUNTY AT THIS TIME...A DRY SUBCLOUD
LAYER AND LIMITED PWAT VALUES (MAIN AOB 0.35 INCH) IS LIKELY KEEPING
ANYTHING MORE THAN A SPRINKLE OR LIGHT SHOWER FROM REACHING THE
GROUND AT THIS TIME. THE LATEST HRRR HI-RES RUN CONTINUES TO SHOW
THE DEVELOPMENT OF ISOLATED SPRINKLES/SHOWERS ACROSS EXTREME
NORTHERN MARICOPA COUNTY THROUGH THE REMAINDER OF THE MORNING
HOURS...AND INTO THE AFTERNOON AS WELL...WHICH IS DEPICTED WELL IN
OUR CURRENT GRIDDED FORECASTS. THE HRRR ALSO CONTINUE TO SHOW THE
DEVELOPMENT OF MORE WIDESPREAD SHOWER ACTIVITY OVER EXTREME EASTERN
MARICOPA COUNTY AND OVER SOUTHERN GILA COUNTY LATE THIS AFTERNOON
INTO THE EARLY EVENING HOURS AS THE UPPER LOW PASSES OVER THAT
REGION. ALONG WITH THE SHOWER ACTIVITY...SFC HIGH PRESSURE BUILDING
SOUTHWARD INTO THE GREAT BASIN IS STILL EXPECTED TO PRODUCE GUSTY
WINDS DOWN THE LOWER COLORADO RIVER VALLEY...WITH THE BLYTHE ASOS
ALREADY SHOWING 15 KNOT SUSTAINED WINDS...AND THE GFS MOS SHOWING
25KT SUSTAINED WINDS BY THIS AFTERNOON AT THAT SITE. HOWEVER...IT
APPEARS THAT WINDS WILL LIKELY REMAIN JUST BELOW WIND ADVISORY
CRITERIA DUE TO LIMITED AREAL AND TEMPORAL COVERAGE. AS FAR AS THE
VERY SHORT TERM IS CONCERNED...OTHER THAN SOME MINOR ADJUSTMENTS TO
THE HOURLY TEMPERATURE...DEWPOINT...AND WIND GRIDS...CURRENT GRIDDED
AND ZONE FORECASTS STILL LOOK GOOD.
&&
.PREVIOUS DISCUSSION...
TODAY THROUGH FRIDAY...
THE MAIN VORT MAX ASSOCIATED WITH THE SHORT WAVE OVER THE MOHAVE
DESERT AND ARIZONA IS CENTERED BETWEEN KINGMAN AND LAS VEGAS EARLY
THIS MORNING. RADAR ECHOES HAVE BEEN WEAK BUT WHERE THEY HAVE BEEN
STRONGEST...CLOSEST TO THE VORT MAX CENTER...SOME VERY LIGHT RAIN
HAS OCCURRED. DESPITE DECENT DYNAMICAL FORCING THE MOISTURE
AVAILABILITY IS MEAGER AS IS EVIDENT IN THE BLENDED TPW IMAGERY WITH
PWAT VALUES BARELY OVER HALF AN INCH. THE HRRR HAS BEEN HANDLING
THINGS WELL OVERNIGHT AND IT SHOWS LIGHT PRECIP TRACKING JUST NORTH
OF OUR FORECAST AREA UNTIL LATE THIS AFTERNOON WHERE IT DEPICTS
ISOLATED SHOWERS PUSHING INTO NORTHERN MARICOPA COUNTY AND SOUTHERN
GILA COUNTY. OTHER HI-RES MODELS FROM NCEP AND LOCAL SOURCES DEPICT
A SIMILAR PATTERN. THIS IS LIKELY DUE JUST ENOUGH INSTABILITY TO GET
SOME SHALLOW CONVECTION GOING...NAM BOUNDARY LAYER CAPE INDICATING
100-150 J/KG. ANTICIPATE CAPE TO BE TOO WEAK TO GET THUNDERSTORMS
GOING BUT IT WOULD NOT BE IMPOSSIBLE TO GET A STRAY LIGHTNING
STRIKE. BETTER OPPORTUNITY FOR PRECIP IN OUR FORECAST AREA WILL BE
OVER THE HIGHER TERRAIN NORTHEAST AND EAST OF PHOENIX. POPS LINGER
OVER THAT AREA TONIGHT BEFORE TAPERING OFF. WINDY CONDITIONS FROM
THE NORTH CAN BE EXPECTED OVER SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...MOST NOTICEABLY OVER THE LOWER COLORADO RIVER
VALLEY...WHERE PEAK GUSTS MAY GET CLOSE TO WIND ADVISORY
CRITERIA...LIGHTER WINDS OVER SOUTH-CENTRAL ARIZONA. ANTICIPATE SOME
COOLING TODAY AS WELL.
RIGHT BEHIND THIS FIRST SHORT WAVE A MORE VIGOROUS ONE COMES DOWN
FROM THE NORTH AND TRACKS ACROSS EASTERN ARIZONA LATE TONIGHT AND
THURSDAY MORNING. MOISTURE LOOKS TO BE TOO LIMITED FOR ANY POPS WITH
IT OVER OUR AREA. HOWEVER...IT TURN UP THE NORTHEASTERLY BREEZINESS
OVER OUR EASTERN AREAS INCLUDING PHOENIX METRO...LESS WINDY SW AZ
AND SE CAL. IT WILL ALSO INTRODUCE ADDITIONAL COOLING BRINGING HIGH
TEMPS THURSDAY INTO THE 60S ON THE LOWER DESERTS.
ANOTHER SHORT WAVE MOVES SOUTHWARD ACROSS THE FORECAST AREA FRIDAY
BUT IT IS WEAK AND THE AIR WILL BE MUCH TOO DRY FOR ANY PRECIP
THREAT. PART OF THE REASON IT IS WEAK IT DUE TO A SPLIT IN THE
NORTHERLY FLOW WHERE MORE OF THE ENERGY TRACKS WEST. IN
FACT...THERE IS GOOD MODEL AGREEMENT THAT IT WILL DEEPEN INTO A
CLOSED LOW WEST OF BAJA.
SATURDAY AND SUNDAY...
A STRONG PACIFIC RIDGE BUILDS OVER THE WESTERN STATES THIS WEEKEND
FOR A SIGNIFICANT WARMING TREND. ANTICIPATE LINGERING NORTHEASTERLY
BREEZINESS INTO EARLY NEXT WEEK. MADE SOME MINOR DOWNWARD
ADJUSTMENTS TO THE TEMPS COMPARED TO PREVIOUS FORECAST PACKAGE DUE
TO MORE CLOUDINESS ANTICIPATED.
MONDAY AND TUESDAY...
THE UPPER LOW WEST OF BAJA IS ADVERTISED TO MOVE NORTHWARD MONDAY
AND TUESDAY. WITH THE RIDGE CENTERED OVER THE INTERMOUNTAIN
WEST...THE LOW WEAKENS QUITE A BIT. HOWEVER...IT WILL HAVE A LOT OF
MOISTURE TO WORK WITH. THUS INTRODUCED SLIGHT CHANCE POPS ACROSS THE
FORECAST AREA FOR MONDAY AND TUESDAY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL.
COLD FRONTAL PASSAGE AROUND 17Z WED...OTHERWISE THROUGH 00Z THU...
BKN CLDS AOA 15 THSD AGL...VIRGA SHWRS. INCREASING NW WIND 8 TO 12
KNOTS PARTICULARLY AFTER 19Z. FROM 00Z THU THROUGH 12Z THU...
CLEAR SKIES. INCREASING NORTHEAST WIND 8 TO 12 KNOTS STRONGEST
TOWARD 12Z THU.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH.
COLD FRONTAL PASSAGE AROUND 14Z WED...OTHERWISE THROUGH 02Z THU...
INCREASING NORTH WIND 15 TO 25 KNOTS...STRONGEST AFTER 18Z AND
FOCUSED DOWN THE COLORADO RIVER. GUSTS TO 30 KNOTS POSSIBLE ALONG
THE COLORADO RIVER. MOSTLY CLEAR SKIES. FROM 02Z THU THROUGH 12Z
THU...DIMINISHING WIND BUT SUSTAINED 12 TO 15 KNOTS OVERNIGHT.
MOSTLY CLEAR SKIES.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
FRIDAY THROUGH WEDNESDAY...
FRIDAY AND SATURDAY...AFTERNOON NORTH TO NORTHEAST WIND 10 TO 20
MPH...PARTICULARLY ALONG THE COLORADO RIVER VALLEY. MOSTLY CLEAR
SKIES. MINIMUM RELATIVE HUMIDITIES IN THE 10 TO 20 PERCENT RANGE
WITH ABOVE NORMAL AFTERNOON TEMPERATURES. SUNDAY THROUGH
WEDNESDAY...CONTINUE DRY WEATHER AND LIGHT WIND. MINIMUM RELATIVE
HUMIDITIES INCREASING INTO THE 25 TO 30 PERCENT RANGE BY WEDNESDAY.
ABOVE NORMAL TEMPERATURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...PERCHA/AJ
AVIATION...VASQUEZ
FIRE WEATHER...VASQUEZ
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
415 AM MST WED JAN 21 2015
.UPDATE...AVIATION AND FIRE WEATHER DISCUSSIONS.
&&
.SYNOPSIS...
A SMALL LOW PRESSURE SYSTEM MOVING ACROSS THE MOHAVE DESERT AND
ARIZONA TODAY WILL LEAD TO A CHANCE OF SHOWERS OVER MAINLY NORTHERN
ARIZONA...WITH ONLY A SLIGHT CHANCE OVER THE CENTRAL ARIZONA
DESERTS. STRONG NORTHERLY WINDS WILL DEVELOP OVER THE LOWER THE
COLORADO RIVER VALLEY AND ADJACENT AREAS...LESS WIND ELSEWHERE.
BREEZY TO WINDY CONDITIONS EXPAND TO CENTRAL AND EASTERN ARIZONA
THURSDAY. ADDITIONAL COOLING CAN BE EXPECTED AS WELL. TEMPERATURES
REBOUND OVER THE WEEKEND AS HIGH PRESSURE BUILDS IN. INCREASED
CLOUDINESS AND A SLIGHT CHANCE OF SHOWERS IS POSSIBLE EARLY NEXT
WEEK.
&&
.DISCUSSION...
TODAY THROUGH FRIDAY...
THE MAIN VORT MAX ASSOCIATED WITH THE SHORT WAVE OVER THE MOHAVE
DESERT AND ARIZONA IS CENTERED BETWEEN KINGMAN AND LAS VEGAS EARLY
THIS MORNING. RADAR ECHOES HAVE BEEN WEAK BUT WHERE THEY HAVE BEEN
STRONGEST...CLOSEST TO THE VORT MAX CENTER...SOME VERY LIGHT RAIN
HAS OCCURRED. DESPITE DECENT DYNAMICAL FORCING THE MOISTURE
AVAILABILITY IS MEAGER AS IS EVIDENT IN THE BLENDED TPW IMAGERY WITH
PWAT VALUES BARELY OVER HALF AN INCH. THE HRRR HAS BEEN HANDLING
THINGS WELL OVERNIGHT AND IT SHOWS LIGHT PRECIP TRACKING JUST NORTH
OF OUR FORECAST AREA UNTIL LATE THIS AFTERNOON WHERE IT DEPICTS
ISOLATED SHOWERS PUSHING INTO NORTHERN MARICOPA COUNTY AND SOUTHERN
GILA COUNTY. OTHER HI-RES MODELS FROM NCEP AND LOCAL SOURCES DEPICT
A SIMILAR PATTERN. THIS IS LIKELY DUE JUST ENOUGH INSTABILITY TO GET
SOME SHALLOW CONVECTION GOING...NAM BOUNDARY LAYER CAPE INDICATING
100-150 J/KG. ANTICIPATE CAPE TO BE TOO WEAK TO GET THUNDERSTORMS
GOING BUT IT WOULD NOT BE IMPOSSIBLE TO GET A STRAY LIGHTNING
STRIKE. BETTER OPPORTUNITY FOR PRECIP IN OUR FORECAST AREA WILL BE
OVER THE HIGHER TERRAIN NORTHEAST AND EAST OF PHOENIX. POPS LINGER
OVER THAT AREA TONIGHT BEFORE TAPERING OFF. WINDY CONDITIONS FROM
THE NORTH CAN BE EXPECTED OVER SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...MOST NOTICEABLY OVER THE LOWER COLORADO RIVER
VALLEY...WHERE PEAK GUSTS MAY GET CLOSE TO WIND ADVISORY
CRITERIA...LIGHTER WINDS OVER SOUTH-CENTRAL ARIZONA. ANTICIPATE SOME
COOLING TODAY AS WELL.
RIGHT BEHIND THIS FIRST SHORT WAVE A MORE VIGOROUS ONE COMES DOWN
FROM THE NORTH AND TRACKS ACROSS EASTERN ARIZONA LATE TONIGHT AND
THURSDAY MORNING. MOISTURE LOOKS TO BE TOO LIMITED FOR ANY POPS WITH
IT OVER OUR AREA. HOWEVER...IT TURN UP THE NORTHEASTERLY BREEZINESS
OVER OUR EASTERN AREAS INCLUDING PHOENIX METRO...LESS WINDY SW AZ
AND SE CAL. IT WILL ALSO INTRODUCE ADDITIONAL COOLING BRINGING HIGH
TEMPS THURSDAY INTO THE 60S ON THE LOWER DESERTS.
ANOTHER SHORT WAVE MOVES SOUTHWARD ACROSS THE FORECAST AREA FRIDAY
BUT IT IS WEAK AND THE AIR WILL BE MUCH TOO DRY FOR ANY PRECIP
THREAT. PART OF THE REASON IT IS WEAK IT DUE TO A SPLIT IN THE
NORTHERLY FLOW WHERE MORE OF THE ENERGY TRACKS WEST. IN
FACT...THERE IS GOOD MODEL AGREEMENT THAT IT WILL DEEPEN INTO A
CLOSED LOW WEST OF BAJA.
SATURDAY AND SUNDAY...
A STRONG PACIFIC RIDGE BUILDS OVER THE WESTERN STATES THIS WEEKEND
FOR A SIGNIFICANT WARMING TREND. ANTICIPATE LINGERING NORTHEASTERLY
BREEZINESS INTO EARLY NEXT WEEK. MADE SOME MINOR DOWNWARD
ADJUSTMENTS TO THE TEMPS COMPARED TO PREVIOUS FORECAST PACKAGE DUE
TO MORE CLOUDINESS ANTICIPATED.
MONDAY AND TUESDAY...
THE UPPER LOW WEST OF BAJA IS ADVERTISED TO MOVE NORTHWARD MONDAY
AND TUESDAY. WITH THE RIDGE CENTERED OVER THE INTERMOUNTAIN
WEST...THE LOW WEAKENS QUITE A BIT. HOWEVER...IT WILL HAVE A LOT OF
MOISTURE TO WORK WITH. THUS INTRODUCED SLIGHT CHANCE POPS ACROSS THE
FORECAST AREA FOR MONDAY AND TUESDAY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL.
COLD FRONTAL PASSAGE AROUND 17Z WED...OTHERWISE THROUGH 00Z THU...
BKN CLDS AOA 15 THSD AGL...VIRGA SHWRS. INCREASING NW WIND 8 TO 12
KNOTS PARTICULARLY AFTER 19Z. FROM 00Z THU THROUGH 12Z THU...
CLEAR SKIES. INCREASING NORTHEAST WIND 8 TO 12 KNOTS STRONGEST
TOWARD 12Z THU.
SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH.
COLD FRONTAL PASSAGE AROUND 14Z WED...OTHERWISE THROUGH 02Z THU...
INCREASING NORTH WIND 15 TO 25 KNOTS...STRONGEST AFTER 18Z AND
FOCUSED DOWN THE COLORADO RIVER. GUSTS TO 30 KNOTS POSSIBLE ALONG
THE COLORADO RIVER. MOSTLY CLEAR SKIES. FROM 02Z THU THROUGH 12Z
THU...DIMINISHING WIND BUT SUSTAINED 12 TO 15 KNOTS OVERNIGHT.
MOSTLY CLEAR SKIES.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
FRIDAY THROUGH WEDNESDAY...
FRIDAY AND SATURDAY...AFTERNOON NORTH TO NORTHEAST WIND 10 TO 20
MPH...PARTICULARLY ALONG THE COLORADO RIVER VALLEY. MOSTLY CLEAR
SKIES. MINIMUM RELATIVE HUMIDITIES IN THE 10 TO 20 PERCENT RANGE
WITH ABOVE NORMAL AFTERNOON TEMPERATURES. SUNDAY THROUGH
WEDNESDAY...CONTINUE DRY WEATHER AND LIGHT WIND. MINIMUM RELATIVE
HUMIDITIES INCREASING INTO THE 25 TO 30 PERCENT RANGE BY WEDNESDAY.
ABOVE NORMAL TEMPERATURES.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...AJ
AVIATION...VASQUEZ
FIRE WEATHER...VASQUEZ
AREA FORECAST DISCUSSION
NWS PHOENIX AZ
345 AM MST WED JAN 21 2015
.SYNOPSIS...
A SMALL LOW PRESSURE SYSTEM MOVING ACROSS THE MOHAVE DESERT AND
ARIZONA TODAY WILL LEAD TO A CHANCE OF SHOWERS OVER MAINLY NORTHERN
ARIZONA...WITH ONLY A SLIGHT CHANCE OVER THE CENTRAL ARIZONA
DESERTS. STRONG NORTHERLY WINDS WILL DEVELOP OVER THE LOWER THE
COLORADO RIVER VALLEY AND ADJACENT AREAS...LESS WIND ELSEWHERE.
BREEZY TO WINDY CONDITIONS EXPAND TO CENTRAL AND EASTERN ARIZONA
THURSDAY. ADDITIONAL COOLING CAN BE EXPECTED AS WELL. TEMPERATURES
REBOUND OVER THE WEEKEND AS HIGH PRESSURE BUILDS IN. INCREASED
CLOUDINESS AND A SLIGHT CHANCE OF SHOWERS IS POSSIBLE EARLY NEXT
WEEK.
&&
.DISCUSSION...
TODAY THROUGH FRIDAY...
THE MAIN VORT MAX ASSOCIATED WITH THE SHORT WAVE OVER THE MOHAVE
DESERT AND ARIZONA IS CENTERED BETWEEN KINGMAN AND LAS VEGAS EARLY
THIS MORNING. RADAR ECHOES HAVE BEEN WEAK BUT WHERE THEY HAVE BEEN
STRONGEST...CLOSEST TO THE VORT MAX CENTER...SOME VERY LIGHT RAIN
HAS OCCURRED. DESPITE DECENT DYNAMICAL FORCING THE MOISTURE
AVAILABILITY IS MEAGER AS IS EVIDENT IN THE BLENDED TPW IMAGERY WITH
PWAT VALUES BARELY OVER HALF AN INCH. THE HRRR HAS BEEN HANDLING
THINGS WELL OVERNIGHT AND IT SHOWS LIGHT PRECIP TRACKING JUST NORTH
OF OUR FORECAST AREA UNTIL LATE THIS AFTERNOON WHERE IT DEPICTS
ISOLATED SHOWERS PUSHING INTO NORTHERN MARICOPA COUNTY AND SOUTHERN
GILA COUNTY. OTHER HI-RES MODELS FROM NCEP AND LOCAL SOURCES DEPICT
A SIMILAR PATTERN. THIS IS LIKELY DUE JUST ENOUGH INSTABILITY TO GET
SOME SHALLOW CONVECTION GOING...NAM BOUNDARY LAYER CAPE INDICATING
100-150 J/KG. ANTICIPATE CAPE TO BE TOO WEAK TO GET THUNDERSTORMS
GOING BUT IT WOULD NOT BE IMPOSSIBLE TO GET A STRAY LIGHTNING
STRIKE. BETTER OPPORTUNITY FOR PRECIP IN OUR FORECAST AREA WILL BE
OVER THE HIGHER TERRAIN NORTHEAST AND EAST OF PHOENIX. POPS LINGER
OVER THAT AREA TONIGHT BEFORE TAPERING OFF. WINDY CONDITIONS FROM
THE NORTH CAN BE EXPECTED OVER SOUTHWEST ARIZONA AND SOUTHEAST
CALIFORNIA...MOST NOTICEABLY OVER THE LOWER COLORADO RIVER
VALLEY...WHERE PEAK GUSTS MAY GET CLOSE TO WIND ADVISORY
CRITERIA...LIGHTER WINDS OVER SOUTH-CENTRAL ARIZONA. ANTICIPATE SOME
COOLING TODAY AS WELL.
RIGHT BEHIND THIS FIRST SHORT WAVE A MORE VIGOROUS ONE COMES DOWN
FROM THE NORTH AND TRACKS ACROSS EASTERN ARIZONA LATE TONIGHT AND
THURSDAY MORNING. MOISTURE LOOKS TO BE TOO LIMITED FOR ANY POPS WITH
IT OVER OUR AREA. HOWEVER...IT TURN UP THE NORTHEASTERLY BREEZINESS
OVER OUR EASTERN AREAS INCLUDING PHOENIX METRO...LESS WINDY SW AZ
AND SE CAL. IT WILL ALSO INTRODUCE ADDITIONAL COOLING BRINGING HIGH
TEMPS THURSDAY INTO THE 60S ON THE LOWER DESERTS.
ANOTHER SHORT WAVE MOVES SOUTHWARD ACROSS THE FORECAST AREA FRIDAY
BUT IT IS WEAK AND THE AIR WILL BE MUCH TOO DRY FOR ANY PRECIP
THREAT. PART OF THE REASON IT IS WEAK IT DUE TO A SPLIT IN THE
NORTHERLY FLOW WHERE MORE OF THE ENERGY TRACKS WEST. IN
FACT...THERE IS GOOD MODEL AGREEMENT THAT IT WILL DEEPEN INTO A
CLOSED LOW WEST OF BAJA.
SATURDAY AND SUNDAY...
A STRONG PACIFIC RIDGE BUILDS OVER THE WESTERN STATES THIS WEEKEND
FOR A SIGNIFICANT WARMING TREND. ANTICIPATE LINGERING NORTHEASTERLY
BREEZINESS INTO EARLY NEXT WEEK. MADE SOME MINOR DOWNWARD
ADJUSTMENTS TO THE TEMPS COMPARED TO PREVIOUS FORECAST PACKAGE DUE
TO MORE CLOUDINESS ANTICIPATED.
MONDAY AND TUESDAY...
THE UPPER LOW WEST OF BAJA IS ADVERTISED TO MOVE NORTHWARD MONDAY
AND TUESDAY. WITH THE RIDGE CENTERED OVER THE INTERMOUNTAIN
WEST...THE LOW WEAKENS QUITE A BIT. HOWEVER...IT WILL HAVE A LOT OF
MOISTURE TO WORK WITH. THUS INTRODUCED SLIGHT CHANCE POPS ACROSS THE
FORECAST AREA FOR MONDAY AND TUESDAY.
&&
.AVIATION...
SOUTH-CENTRAL ARIZONA INCLUDING KPHX...KIWA AND KSDL...AND SOUTHEAST
CALIFORNIA AND SOUTHWEST ARIZONA INCLUDING KIPL AND KBLH...
OPEN WAVE TROF WILL MOVE INTO WESTERN AZ BY AROUND SUNRISE
TOMORROW...BRINGING INCREASING AND THICKENING MID/HIGH CLOUDS TO
SOUTH CENTRAL AZ. EXPECT BKN-OVC DECKS AOA 15K FEET TO DEVELOP AFTER
MIDNIGHT...WITH SOME CLEARING AT THE TAF SITES BY LATE MORNING ON
WEDNESDAY. NO PRECIP EXPECTED AT ANY TAF SITE DURING THE NEXT 24
HOURS. WINDS TO BE LIGHT/VARIABLE OR LIGHT NORTHEAST ACROSS SOUTH
CENTRAL AZ THROUGH MID MORNING WEDNESDAY...BECOMING RELATIVELY
LIGHT NORTHWEST DURING THE AFTERNOON TOMORROW. STRONGER NORTH WINDS
ARE EXPECTED TO DEVELOP AT KBLH DURING THE MORNING HOURS BEHIND THE
EXITING WAVE...WITH GUSTS TO NEAR 30 MPH LIKELY BY EARLY AFTERNOON.
AT KIPL...LESS WIND EXPECTED FAVORING THE WEST THRU MID MORNING...
THEN TURNING MORE TOWARDS THE NORTH WITH SPEEDS MOSTLY AOB 12KT.
AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS.
&&
.FIRE WEATHER...
THURSDAY THROUGH TUESDAY...
BREEZY TO LOCALLY WINDY NORTH TO NORTHEAST WINDS THURSDAY IN THE
AFTERMATH OF WEDNESDAYS COLD FRONT. THE STRONGEST NORTHEAST WINDS...
GUSTS TO 25 MPH...WILL DEVELOP OVER SOUTH CENTRAL ARIZONA GENERALLY
FROM MARICOPA COUNTY EASTWARD. SATURDAY THROUGH TUESDAY...VARIABLE
HIGH CLOUDS ALONG WITH AFTERNOON NORTH TO NORTHEAST BREEZES 8-15 MPH
AREA-WIDE. GOOD RECOVERY AT NIGHT. AFTERNOON TEMPERATURES ON THE
DESERTS ARE EXPECTED IN MID 70S...BUT APPROACHING 80 DEGREES IN
SOUTHEAST CA AND SOUTHWEST AZ SUNDAY AND MONDAY. A MUCH DRIER
AIRMASS WITH LOW HUMIDITY WILL COVER THE REGION THIS PERIOD. MINIMUM
RELATIVE HUMIDITIES WILL RANGE FROM 10 PERCENT IN SOUTHEAST CA...TO
20 PERCENT IN SOUTHERN GILA COUNTY.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...NONE.
CA...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...AND AT WEATHER.GOV/PHOENIX
DISCUSSION...AJ
AVIATION...CB
FIRE WEATHER...VASQUEZ
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1253 PM EST WED JAN 21 2015
.SYNOPSIS...
WEAKENING LOW PRESSURE WILL MOVE ACROSS THE UPPER OHIO RIVER
VALLEY TODAY. MEANWHILE, STRENGTHENING LOW PRESSURE WAS LOCATED
OFF CAPE HATTERAS THIS MORNING AND IT WILL MOVE QUICKLY OUT TO SEA
DURING THIS AFTERNOON AND TONIGHT. ON THURSDAY, HIGH PRESSURE WILL
BEGIN BUILDING BACK INTO THE REGION. THIS HIGH PRESSURE WILL MOVE
THROUGH ON FRIDAY BEFORE GIVING WAY TO A LOW PRESSURE SYSTEM
TRACKING UP THE COAST ON SATURDAY. BY MONDAY, ANOTHER AREA OF LOW
PRESSURE WILL DIVE INTO THE OHIO VALLEY AND THEN MOVE NORTHEAST UP
THE EAST COAST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE LEADING EDGE OF THE APPROACHING PRECIPITATION WAS UPON US AT
MIDDAY. HOWEVER, RELATIVELY DRY AIR WAS IN PLACE IN OUR NORTHERN
AND CENTRAL COUNTIES WITH DEW POINT READINGS IN THE SINGLE DIGITS
AND TEENS. DEW POINT READING WERE IN THE 20S ACROSS OUR SOUTH.
THE FIRST OF THE PRECIPITATION SHOULD BEGIN FALLING IN OUR
SOUTHERN COUNTIES EARLY THIS AFTERNOON, THEN IT WILL SPREAD
NORTHEASTWARD AS THE MOISTURE OVERCOMES THE DRY AIR.
THE LATEST HRRR RUN CONTINUES TO SUGGEST THAT THE INITIAL AREA OF
PRECIPITATION WILL SLOWLY WEAKEN AS IT MOVES ACROSS EASTERN
PENNSYLVANIA AND CENTRAL AND NORTHERN NEW JERSEY DURING THE
AFTERNOON AND EVENING HOURS. MEANWHILE, ANOTHER AREA OF
PRECIPITATION IS FORECAST TO DEVELOP OVER THE CHESAPEAKE BAY
REGION EARLY THIS AFTERNOON BEFORE LIFTING ACROSS OUR SOUTHEASTERN
COUNTIES.
WE CONTINUE TO EXPECT SNOWFALL AMOUNTS MAINLY IN THE ONE TO TWO
INCH RANGE IN OUR NORTHERN COUNTIES AND FROM TWO TO FOUR INCHES
ACROSS THE SOUTH. THE EXPECTED TEMPERATURE PROFILES CONTINUE TO
SUGGEST A BIT OF SLEET IN THE SOUTH AND EVEN A LITTLE RAIN IN THE
FAR SOUTHEAST AT THE ONSET. MAXIMUM TEMPERATURES ARE ANTICIPATED
TO RANGE FROM THE UPPER 20S IN OUR FAR NORTH TO THE UPPER 30S IN
SOUTHERN DELAWARE WITH A RELATIVELY LIGHT NORTH TO NORTHEAST WIND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THE LEAD SHORT WAVE MOVES OFFSHORE BY EARLY EVENING AND WHAT
FOLLOWS IS CONSIDERABLY MORE CHANNELIZED. ALSO DURING THE EVENING
THE BEST PREDICTED MID LEVEL QVEC CONVERGENCE MOVES NORTH. THIS
GIVES THE NORTHERN PART OF OUR CWA THE HIGHEST INTO THE EVENING
POPS AS WHAT IS LEFT OF THE INITIAL CLIPPER LOW TRUNDLES THROUGH
OUR CWA.
MIN TEMPS WE TRIED TO STEER LOWER BECAUSE OF THE NEW SNOW COVER.
THE ONE CAVEAT THAT MIGHT WORK AGAINST IT IS THAT MODELS ARE
FORECASTING LOW LEVEL MOISTURE/CLOUDS TO LINGER MOST OF THE NIGHT.
NOT IN THE GRIDS, BUT WE SUPPOSE THERE IS A CHANCE FOR FREEZING
DRIZZLE IF THE CLOUD LAYER IS THICKER THAN WE CURRENTLY BELIEVE.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
THURSDAY THROUGH FRIDAY NIGHT: ON THURSDAY THE CLIPPER SYSTEM
WHICH WILL BRING PRECIPITATION TO THE REGION TODAY WILL BE WELL TO
OUR NORTHEAST. HOWEVER, ANOTHER WEAK SHORTWAVE IS LIKELY TO MOVE
THROUGH THE REGION BEHIND IT EARLY IN THE DAY. THIS WILL LEAD TO
MOSTLY CLOUDY CONDITIONS AND THE POSSIBILITY OF A AN ISOLATED SNOW
FLAKE OR LIGHT SNOW SHOWER, PARTICULARLY ACROSS NORTH NJ AND THE
POCONOS. BY THURSDAY NIGHT, HIGH PRESSURE WILL BUILD BACK INTO THE
REGION WITH CLEARING WHICH WILL LAST THROUGH FRIDAY. ALL ATTENTION
TURNS TO A LOW PRESSURE SYSTEM OVER THE SOUTHEAST UNITED STATES
FRIDAY NIGHT. STAYED CLOSE TO THE MET AND MAV ON TEMPERATURES WITH
LITTLE DISAGREEMENT FROM THE MODELED TWO METER TEMPERATURES.
FRIDAY NIGHT THROUGH SATURDAY NIGHT: MODELING HAS TRENDED
WESTWARD AND FASTER WITH A LOW PRESSURE SYSTEM TRACKING FROM THE
GULF OF MEXICO FRIDAY TOWARD THE OUTER BANKS/VIRGINIA BEACH ON
SATURDAY MORNING. THE WESTWARD/FASTER TREND NOW BRINGS THE TRACK
OF THE LOW JUST OFFSHORE DURING THE DAY SATURDAY. A OVERALL
DECREASE IN THE ENSEMBLE SPREAD COMPARED TO PREVIOUS MODEL RUNS
LEADS TO LESS UNCERTAINTY THAN WITH PREVIOUS FORECAST UPDATES. THE
MAIN UNCERTAINTIES THAT STILL REMAIN ARE HOW FAR WEST THE
PRECIPITATION SHIELD WILL GET AND THE OVERALL THERMAL PROFILES.
THE 00Z NAM LOOKED TO BE A WARM/WEST RAINY OUTLIER BUT DID HAVE
SUPPORT FROM SEVERAL ECMWF ENSEMBLE MEMBERS BASED ON A LOOK AT THE
MEAN. ON THE OTHER SIDE THE 00Z GFS WAS FURTHER OFFSHORE JUST
GETTING THE PRECIPITATION SHIELD INTO THE POCONOS, A MAINLY SNOWY
OUTCOME PHL AND NW WITH MIX ALONG THE COAST. THE 00Z ECMWF WAS
SIMILAR BUT CHANGED THE 1-95 OVER TO RAIN LONGER.
IN TERMS OF WEATHER, DID INCREASE POPS TO LIKELY FROM PHL SE AND
HIGH CHANCE NORTH TO CAPTURE INCREASING CERTAINTY OF A STORM
IMPACTING US IN THIS PERIOD. WITH THIS IN MIND SNOW CHANCES WILL
BEGIN TO INCREASE FROM SOUTH TO NORTH FRIDAY NIGHT WITH AREAS FROM
PHL TO THE SE CHANGING TO RAIN FOR A WHILE ON SATURDAY WITH WAA.
THEN THE CCB COMES THROUGH WITH A CHANGE BACK TO SNOW. MOUNT
POCONO APPEARS TO BE THE NORTHWARD EXTEND OF THE DRY/SNOW LINE
ATTM. THE ALL SNOW/ MIX LINE RUNS ROUGHLY ALONG THE 1-95 CORRIDOR.
COASTAL SECTIONS STAY MAINLY RAIN AFTER STARTING AND ENDING AS A
FEW HOURS OF SNOW. WENT COOLER THAN THE ENSEMBLE AND MOS GUIDANCE
TOOLS SHOW GIVEN THE POTENTIAL FOR SOME DYNAMICAL/ EVAPORATIONAL
COOLING WITH PRECIPITATION. THIS DOES NOT LOOK TO BE AN ICING
EVENT, AS MID-LEVEL AND SURFACE TEMPERATURES SHOULD BE RATHER
CLOSE TO EACH OTHER THROUGHOUT. WITH THE DEVELOPING LOW GOING EAST
AND NORTHEAST OF US, NORTHWEST WINDS MAY INCREASE SOME IN THE
AFTERNOON AND EVENING WITH GUSTS UP TO 20 KNOTS ON LAND. TO MUCH
UNCERTAINTY IN THE QPF TO SUGGEST SNOWFALL ACCUMULATIONS ATTM.
OVERALL, A HIGH IMPACT STORM HAS THE POTENTIAL TO IMPACT THE
REGION IN THIS PERIOD. THE TRACK AND INTENSITY CAN STILL CHANGE
OVER THE UPCOMING DAYS, STAY TUNED.
SUNDAY: A TEMPORARY BREAK BETWEEN SYSTEMS WITH A MIX OF CLOUDS
AND SUN. TEMPERATURES COULD BE COOLER DUE TO SNOW COVER. WENT
COOLER THAN THE ENSEMBLE/ MEX GUIDANCE.
SUNDAY NIGHT THROUGH TUESDAY: ANOTHER SYSTEM DIVES SOUTHEAST INTO
THE OHIO VALLEY AND THEN TURNS UP THE EAST COAST. THIS LOOKS TO BE
ANOTHER SET-UP WHERE THE PRIMARY LOW TRANSFERS IT`S ENERGY TO A
COASTAL LOW. THERE IS A HIGHER DEGREE OF SPREAD IN THE ENSEMBLES
WITH THIS FEATURE IN JUST HOW MUCH IT CAN DIG ACROSS THE OH VALLEY
AND STRENGTHEN ONCE IT REACHES THE EAST COAST. FOR NOW CARRYING A
CHANCE OF SNOW ACROSS THE REGION WITH SOME MIX ACROSS THE COAST,
AS A COOLER AIR MASS MOVES IN. SNOW COVER WILL AGAIN PLAY A ROLE IN
TEMPERATURE FORECASTS BUT DID NOT AS COLD AS THE 00Z ECMWF WHICH
MAY BE THE OTHER EXTREME.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THIS AFTERNOON...VFR CONDITIONS WILL RAPIDLY FALL TO MVFR THEN IFR
AS SNOW OVERSPREADS THE REGION. SOME LIGHT SNOW AT THE ONSET
BEFORE INCREASING IN INTENSITY THROUGH THIS AFTERNOON AND INTO
THIS EVENING. SNOW SHOULD FALL FAST ENOUGH TO ACCUMULATE ON THE
RUNWAYS.
TONIGHT...SNOW WILL CONTINUE INTO THIS EVENING BUT WILL START TO
END FROM SOUTHWEST TO NORTHEAST BETWEEN 02-05Z AT THE TERMINALS.
BOTH CEILINGS AND VISIBILITIES WILL RISE TO MVFR LEVELS WITH
VISIBILITIES CONTINUING TO IMPROVE THROUGH THE NIGHT. CEILINGS
WILL REMAIN AT MVFR LEVELS THROUGH THURSDAY BEFORE STARTING LIFT
THURSDAY AFTERNOON/EVENING.
WINDS WILL BE FAIRLY LIGHT THROUGH THE TAF PERIOD, REMAINING LESS
THAN 10 KNOTS. EAST TO NORTHEAST WINDS TODAY WILL BECOME MORE
NORTHERLY OVERNIGHT AND THEN BECOME NORTHWEST THURSDAY MORNING.
OUTLOOK...
THURSDAY NIGHT THROUGH FRIDAY NIGHT: VFR, DECREASING CLOUDS
THURSDAY NIGHT AND INCREASING CLOUDS FRIDAY NIGHT.
SATURDAY AND SATURDAY NIGHT: MVFR AND IFR CEILINGS AND VSBYS IN
SNOW AND RAIN. MORE RAIN SOUTHEAST OF PHL AND SNOW NORTHWEST OF
PHL. NORTHWEST GUSTS UP TO 20 KNOTS SATURDAY AFTERNOON AND NIGHT.
SUNDAY: VFR.
SUNDAY NIGHT: INCREASING CLOUDS POTENTIAL MVFR CEILINGS LATE WITH
SNOW.
&&
.MARINE...
THE PREDICTED INTENSIFICATION OF THE CLIPPER LOW IS SLOW ENOUGH
THAT SMALL CRAFT ADVISORY WINDS AND SEAS ARE NOT EXPECTED TO BE
REACHED TODAY. STRONGEST WINDS SHOULD BE IN OUR SOUTHERN ATLANTIC
WATERS CLOSEST TO THE LOW. AS THE LOW MOVES FARTHER OFFSHORE
TONIGHT, WINDS WILL BECOME LIGHTER.
OUTLOOK...
THURSDAY THROUGH FRIDAY NIGHT: SUB SCA SEAS AND WINDS INCREASING
FRIDAY NIGHT.
SATURDAY AND SATURDAY NIGHT: SCA SEAS AND GUSTS BY AFTERNOON.
WINDS FROM THE EAST SHIFTING TO NORTHWEST BY SATURDAY NIGHT. SOME
GALE FORCE GUSTS POSSIBLE SATURDAY AFTERNOON AND NIGHT.
SUNDAY AND SUNDAY NIGHT: SEAS AND WIND GUSTS DECREASING BELOW SCA
CRITERIA BY SUNDAY AFTERNOON.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ060-070-071-101>104-106.
NJ...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
NJZ016>024-027.
DE...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
DEZ001-002.
MD...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
MDZ008-012-015-019-020.
MARINE...NONE.
&&
$$
SYNOPSIS...GAINES
NEAR TERM...IOVINO
SHORT TERM...GIGI
LONG TERM...GAINES
AVIATION...GAINES/MEOLA
MARINE...GAINES/GIGI
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1224 PM EST WED JAN 21 2015
.SYNOPSIS...
WEAKENING LOW PRESSURE WILL MOVE ACROSS THE UPPER OHIO RIVER
VALLEY TODAY. MEANWHILE, STRENGTHENING LOW PRESSURE WAS LOCATED
OFF CAPE HATTERAS THIS MORNING AND IT WILL MOVE QUICKLY OUT TO SEA
DURING THIS AFTERNOON AND TONIGHT. ON THURSDAY, HIGH PRESSURE WILL
BEGIN BUILDING BACK INTO THE REGION. THIS HIGH PRESSURE WILL MOVE
THROUGH ON FRIDAY BEFORE GIVING WAY TO A LOW PRESSURE SYSTEM
TRACKING UP THE COAST ON SATURDAY. BY MONDAY, ANOTHER AREA OF LOW
PRESSURE WILL DIVE INTO THE OHIO VALLEY AND THEN MOVE NORTHEAST UP
THE EAST COAST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE LEADING EDGE OF THE APPROACHING PRECIPITATION WAS UPON US AT
MIDDAY. HOWEVER, RELATIVELY DRY AIR WAS IN PLACE IN OUR NORTHERN
AND CENTRAL COUNTIES WITH DEW POINT READINGS IN THE SINGLE DIGITS
AND TEENS. DEW POINT READING WERE IN THE 20S ACROSS OUR SOUTH.
THE FIRST OF THE PRECIPITATION SHOULD BEGIN FALLING IN OUR
SOUTHERN COUNTIES EARLY THIS AFTERNOON, THEN IT WILL SPREAD
NORTHEASTWARD AS THE MOISTURE OVERCOMES THE DRY AIR.
THE LATEST HRRR RUN CONTINUES TO SUGGEST THAT THE INITIAL AREA OF
PRECIPITATION WILL SLOWLY WEAKEN AS IT MOVES ACROSS EASTERN
PENNSYLVANIA AND CENTRAL AND NORTHERN NEW JERSEY DURING THE
AFTERNOON AND EVENING HOURS. MEANWHILE, ANOTHER AREA OF
PRECIPITATION IS FORECAST TO DEVELOP OVER THE CHESAPEAKE BAY
REGION EARLY THIS AFTERNOON BEFORE LIFTING ACROSS OUR SOUTHEASTERN
COUNTIES.
WE CONTINUE TO EXPECT SNOWFALL AMOUNTS MAINLY IN THE ONE TO TWO
INCH RANGE IN OUR NORTHERN COUNTIES AND FROM TWO TO FOUR INCHES
ACROSS THE SOUTH. THE EXPECTED TEMPERATURE PROFILES CONTINUE TO
SUGGEST A BIT OF SLEET IN THE SOUTH AND EVEN A LITTLE RAIN IN THE
FAR SOUTHEAST AT THE ONSET. MAXIMUM TEMPERATURES ARE ANTICIPATED
TO RANGE FROM THE UPPER 20S IN OUR FAR NORTH TO THE UPPER 30S IN
SOUTHERN DELAWARE WITH A RELATIVELY LIGHT NORTH TO NORTHEAST WIND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THE LEAD SHORT WAVE MOVES OFFSHORE BY EARLY EVENING AND WHAT
FOLLOWS IS CONSIDERABLY MORE CHANNELIZED. ALSO DURING THE EVENING
THE BEST PREDICTED MID LEVEL QVEC CONVERGENCE MOVES NORTH. THIS
GIVES THE NORTHERN PART OF OUR CWA THE HIGHEST INTO THE EVENING
POPS AS WHAT IS LEFT OF THE INITIAL CLIPPER LOW TRUNDLES THROUGH
OUR CWA.
MIN TEMPS WE TRIED TO STEER LOWER BECAUSE OF THE NEW SNOW COVER.
THE ONE CAVEAT THAT MIGHT WORK AGAINST IT IS THAT MODELS ARE
FORECASTING LOW LEVEL MOISTURE/CLOUDS TO LINGER MOST OF THE NIGHT.
NOT IN THE GRIDS, BUT WE SUPPOSE THERE IS A CHANCE FOR FREEZING
DRIZZLE IF THE CLOUD LAYER IS THICKER THAN WE CURRENTLY BELIEVE.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
THURSDAY THROUGH FRIDAY NIGHT: ON THURSDAY THE CLIPPER SYSTEM
WHICH WILL BRING PRECIPITATION TO THE REGION TODAY WILL BE WELL TO
OUR NORTHEAST. HOWEVER, ANOTHER WEAK SHORTWAVE IS LIKELY TO MOVE
THROUGH THE REGION BEHIND IT EARLY IN THE DAY. THIS WILL LEAD TO
MOSTLY CLOUDY CONDITIONS AND THE POSSIBILITY OF A AN ISOLATED SNOW
FLAKE OR LIGHT SNOW SHOWER, PARTICULARLY ACROSS NORTH NJ AND THE
POCONOS. BY THURSDAY NIGHT, HIGH PRESSURE WILL BUILD BACK INTO THE
REGION WITH CLEARING WHICH WILL LAST THROUGH FRIDAY. ALL ATTENTION
TURNS TO A LOW PRESSURE SYSTEM OVER THE SOUTHEAST UNITED STATES
FRIDAY NIGHT. STAYED CLOSE TO THE MET AND MAV ON TEMPERATURES WITH
LITTLE DISAGREEMENT FROM THE MODELED TWO METER TEMPERATURES.
FRIDAY NIGHT THROUGH SATURDAY NIGHT: MODELING HAS TRENDED
WESTWARD AND FASTER WITH A LOW PRESSURE SYSTEM TRACKING FROM THE
GULF OF MEXICO FRIDAY TOWARD THE OUTER BANKS/VIRGINIA BEACH ON
SATURDAY MORNING. THE WESTWARD/FASTER TREND NOW BRINGS THE TRACK
OF THE LOW JUST OFFSHORE DURING THE DAY SATURDAY. A OVERALL
DECREASE IN THE ENSEMBLE SPREAD COMPARED TO PREVIOUS MODEL RUNS
LEADS TO LESS UNCERTAINTY THAN WITH PREVIOUS FORECAST UPDATES. THE
MAIN UNCERTAINTIES THAT STILL REMAIN ARE HOW FAR WEST THE
PRECIPITATION SHIELD WILL GET AND THE OVERALL THERMAL PROFILES.
THE 00Z NAM LOOKED TO BE A WARM/WEST RAINY OUTLIER BUT DID HAVE
SUPPORT FROM SEVERAL ECMWF ENSEMBLE MEMBERS BASED ON A LOOK AT THE
MEAN. ON THE OTHER SIDE THE 00Z GFS WAS FURTHER OFFSHORE JUST
GETTING THE PRECIPITATION SHIELD INTO THE POCONOS, A MAINLY SNOWY
OUTCOME PHL AND NW WITH MIX ALONG THE COAST. THE 00Z ECMWF WAS
SIMILAR BUT CHANGED THE 1-95 OVER TO RAIN LONGER.
IN TERMS OF WEATHER, DID INCREASE POPS TO LIKELY FROM PHL SE AND
HIGH CHANCE NORTH TO CAPTURE INCREASING CERTAINTY OF A STORM
IMPACTING US IN THIS PERIOD. WITH THIS IN MIND SNOW CHANCES WILL
BEGIN TO INCREASE FROM SOUTH TO NORTH FRIDAY NIGHT WITH AREAS FROM
PHL TO THE SE CHANGING TO RAIN FOR A WHILE ON SATURDAY WITH WAA.
THEN THE CCB COMES THROUGH WITH A CHANGE BACK TO SNOW. MOUNT
POCONO APPEARS TO BE THE NORTHWARD EXTEND OF THE DRY/SNOW LINE
ATTM. THE ALL SNOW/ MIX LINE RUNS ROUGHLY ALONG THE 1-95 CORRIDOR.
COASTAL SECTIONS STAY MAINLY RAIN AFTER STARTING AND ENDING AS A
FEW HOURS OF SNOW. WENT COOLER THAN THE ENSEMBLE AND MOS GUIDANCE
TOOLS SHOW GIVEN THE POTENTIAL FOR SOME DYNAMICAL/ EVAPORATIONAL
COOLING WITH PRECIPITATION. THIS DOES NOT LOOK TO BE AN ICING
EVENT, AS MID-LEVEL AND SURFACE TEMPERATURES SHOULD BE RATHER
CLOSE TO EACH OTHER THROUGHOUT. WITH THE DEVELOPING LOW GOING EAST
AND NORTHEAST OF US, NORTHWEST WINDS MAY INCREASE SOME IN THE
AFTERNOON AND EVENING WITH GUSTS UP TO 20 KNOTS ON LAND. TO MUCH
UNCERTAINTY IN THE QPF TO SUGGEST SNOWFALL ACCUMULATIONS ATTM.
OVERALL, A HIGH IMPACT STORM HAS THE POTENTIAL TO IMPACT THE
REGION IN THIS PERIOD. THE TRACK AND INTENSITY CAN STILL CHANGE
OVER THE UPCOMING DAYS, STAY TUNED.
SUNDAY: A TEMPORARY BREAK BETWEEN SYSTEMS WITH A MIX OF CLOUDS
AND SUN. TEMPERATURES COULD BE COOLER DUE TO SNOW COVER. WENT
COOLER THAN THE ENSEMBLE/ MEX GUIDANCE.
SUNDAY NIGHT THROUGH TUESDAY: ANOTHER SYSTEM DIVES SOUTHEAST INTO
THE OHIO VALLEY AND THEN TURNS UP THE EAST COAST. THIS LOOKS TO BE
ANOTHER SET-UP WHERE THE PRIMARY LOW TRANSFERS IT`S ENERGY TO A
COASTAL LOW. THERE IS A HIGHER DEGREE OF SPREAD IN THE ENSEMBLES
WITH THIS FEATURE IN JUST HOW MUCH IT CAN DIG ACROSS THE OH VALLEY
AND STRENGTHEN ONCE IT REACHES THE EAST COAST. FOR NOW CARRYING A
CHANCE OF SNOW ACROSS THE REGION WITH SOME MIX ACROSS THE COAST,
AS A COOLER AIR MASS MOVES IN. SNOW COVER WILL AGAIN PLAY A ROLE IN
TEMPERATURE FORECASTS BUT DID NOT AS COLD AS THE 00Z ECMWF WHICH
MAY BE THE OTHER EXTREME.
&&
.AVIATION /17Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THIS AFTERNOON, QUICKLY BECOMING IFR WITH THE ONSET OF SNOW
ESTIMATED BETWEEN 18Z AND 20Z FOR MOST TERMINALS. GENERAL
DIRECTION OF MOVEMENT SOUTHWEST TO NORTHEAST. HEAVY ENOUGH SNOW
FOR ACCUMS ON TARMAC. THERE MAY BE SOME MIXED PCPN AT THE START AT
KMIV AND KACY. CIGS SHOULD ALSO LOWER TO IFR. NORTHEAST WINDS
SHOULD AVERAGE 5 TO 10 KNOTS.
THIS EVENING, CONDITIONS IMPROVING TO MVFR CIGS AS SNOW TAPERS
OFF AND ENDS. VSBYS SHOULD BE VFR ALL TERMINALS BY LATE EVENING.
NORTH WINDS WILL AVERAGE 5 TO 10 KNOTS.
OUTLOOK...
THURSDAY THROUGH FRIDAY NIGHT: VFR, DECREASING CLOUDS THURSDAY
AND INCREASING CLOUDS FRIDAY NIGHT.
SATURDAY AND SATURDAY NIGHT: MVFR AND IFR CEILINGS AND VSBYS IN
SNOW AND RAIN. MORE RAIN SOUTHEAST OF PHL AND SNOW NORTHWEST OF
PHL. NORTHWEST GUSTS UP TO 20 KNOTS SATURDAY AFTERNOON AND NIGHT.
SUNDAY: VFR.
SUNDAY NIGHT: INCREASING CLOUDS POTENTIAL MVFR CEILINGS LATE WITH
SNOW.
&&
.MARINE...
THE PREDICTED INTENSIFICATION OF THE CLIPPER LOW IS SLOW ENOUGH
THAT SMALL CRAFT ADVISORY WINDS AND SEAS ARE NOT EXPECTED TO BE
REACHED TODAY. STRONGEST WINDS SHOULD BE IN OUR SOUTHERN ATLANTIC
WATERS CLOSEST TO THE LOW. AS THE LOW MOVES FARTHER OFFSHORE
TONIGHT, WINDS WILL BECOME LIGHTER.
OUTLOOK...
THURSDAY THROUGH FRIDAY NIGHT: SUB SCA SEAS AND WINDS INCREASING
FRIDAY NIGHT.
SATURDAY AND SATURDAY NIGHT: SCA SEAS AND GUSTS BY AFTERNOON.
WINDS FROM THE EAST SHIFTING TO NORTHWEST BY SATURDAY NIGHT. SOME
GALE FORCE GUSTS POSSIBLE SATURDAY AFTERNOON AND NIGHT.
SUNDAY AND SUNDAY NIGHT: SEAS AND WIND GUSTS DECREASING BELOW SCA
CRITERIA BY SUNDAY AFTERNOON.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ060-070-071-101>104-106.
NJ...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
NJZ016>024-027.
DE...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
DEZ001-002.
MD...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
MDZ008-012-015-019-020.
MARINE...NONE.
&&
$$
SYNOPSIS...GAINES
NEAR TERM...IOVINO
SHORT TERM...GIGI
LONG TERM...GAINES
AVIATION...GAINES/GIGI
MARINE...GAINES/GIGI
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
954 AM EST WED JAN 21 2015
.SYNOPSIS...
WEAKENING LOW PRESSURE WILL MOVE ACROSS THE UPPER OHIO RIVER
VALLEY TODAY. MEANWHILE, STRENGTHENING LOW PRESSURE WAS LOCATED
OFF CAPE HATTERAS THIS MORNING AND IT WILL MOVE QUICKLY OUT TO SEA
DURING THIS AFTERNOON AND TONIGHT. ON THURSDAY, HIGH PRESSURE WILL
BEGIN BUILDING BACK INTO THE REGION. THIS HIGH PRESSURE WILL MOVE
THROUGH ON FRIDAY BEFORE GIVING WAY TO A LOW PRESSURE SYSTEM
TRACKING UP THE COAST ON SATURDAY. BY MONDAY, ANOTHER AREA OF LOW
PRESSURE WILL DIVE INTO THE OHIO VALLEY AND THEN MOVE NORTHEAST UP
THE EAST COAST.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE LEADING EDGE OF THE APPROACHING PRECIPITATION WAS INTO
CENTRAL PENNSYLVANIA, WESTERN MARYLAND AND EASTERN WEST VIRGINIA
AT MID MORNING. MEANWHILE, RELATIVELY DRY AIR WAS IN PLACE IN OUR
NORTHERN AND CENTRAL COUNTIES WITH DEW POINT READINGS IN THE
SINGLE DIGITS AND TEENS. DEW POINT READING WERE IN THE 20S ACROSS
OUR SOUTH.
IT CONTINUES TO APPEARS AS THOUGH THE INITIAL PRECIPITATION WILL
BEGIN TO NOSE ACROSS OUR SOUTHERN COUNTIES DURING THE LATE MORNING
BEFORE LIFTING NORTHEASTWARD AS THE MOISTURE OVERCOMES THE DRY
AIR.
THE LATEST HRRR RUN CONTINUES TO SUGGEST THAT THE INITIAL AREA
OF PRECIPITATION WILL SLOWLY WEAKEN AS IT MOVES ACROSS EASTERN
PENNSYLVANIA AND CENTRAL AND NORTHERN NEW JERSEY DURING THE
AFTERNOON AND EVENING HOURS. MEANWHILE, ANOTHER AREA OF
PRECIPITATION IS FORECAST TO DEVELOP OVER EASTERN VIRGINIA AROUND
MIDDAY BEFORE LIFTING ACROSS OUR SOUTHEASTERN COUNTIES.
WE CONTINUE TO EXPECT SNOWFALL AMOUNTS MAINLY IN THE ONE TO TWO
INCH RANGE IN OUR NORTHERN COUNTIES AND FROM TWO TO FOUR INCHES
ACROSS THE SOUTH. THE EXPECTED TEMPERATURE PROFILES CONTINUE TO
SUGGEST A BIT OF SLEET IN THE SOUTH AND EVEN A LITTLE RAIN IN THE
FAR SOUTHEAST AT THE ONSET. MAXIMUM TEMPERATURES ARE ANTICIPATED
TO RANGE FROM THE UPPER 20S IN OUR FAR NORTH TO THE UPPER 30S IN
SOUTHERN DELAWARE WITH A RELATIVELY LIGHT NORTH TO NORTHEAST WIND.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THE LEAD SHORT WAVE MOVES OFFSHORE BY EARLY EVENING AND WHAT
FOLLOWS IS CONSIDERABLY MORE CHANNELIZED. ALSO DURING THE EVENING
THE BEST PREDICTED MID LEVEL QVEC CONVERGENCE MOVES NORTH. THIS
GIVES THE NORTHERN PART OF OUR CWA THE HIGHEST INTO THE EVENING
POPS AS WHAT IS LEFT OF THE INITIAL CLIPPER LOW TRUNDLES THROUGH
OUR CWA.
MIN TEMPS WE TRIED TO STEER LOWER BECAUSE OF THE NEW SNOW COVER.
THE ONE CAVEAT THAT MIGHT WORK AGAINST IT IS THAT MODELS ARE
FORECASTING LOW LEVEL MOISTURE/CLOUDS TO LINGER MOST OF THE NIGHT.
NOT IN THE GRIDS, BUT WE SUPPOSE THERE IS A CHANCE FOR FREEZING
DRIZZLE IF THE CLOUD LAYER IS THICKER THAN WE CURRENTLY BELIEVE.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
THURSDAY THROUGH FRIDAY NIGHT: ON THURSDAY THE CLIPPER SYSTEM
WHICH WILL BRING PRECIPITATION TO THE REGION TODAY WILL BE WELL TO
OUR NORTHEAST. HOWEVER, ANOTHER WEAK SHORTWAVE IS LIKELY TO MOVE
THROUGH THE REGION BEHIND IT EARLY IN THE DAY. THIS WILL LEAD TO
MOSTLY CLOUDY CONDITIONS AND THE POSSIBILITY OF A AN ISOLATED SNOW
FLAKE OR LIGHT SNOW SHOWER, PARTICULARLY ACROSS NORTH NJ AND THE
POCONOS. BY THURSDAY NIGHT, HIGH PRESSURE WILL BUILD BACK INTO THE
REGION WITH CLEARING WHICH WILL LAST THROUGH FRIDAY. ALL ATTENTION
TURNS TO A LOW PRESSURE SYSTEM OVER THE SOUTHEAST UNITED STATES
FRIDAY NIGHT. STAYED CLOSE TO THE MET AND MAV ON TEMPERATURES WITH
LITTLE DISAGREEMENT FROM THE MODELED TWO METER TEMPERATURES.
FRIDAY NIGHT THROUGH SATURDAY NIGHT: MODELING HAS TRENDED
WESTWARD AND FASTER WITH A LOW PRESSURE SYSTEM TRACKING FROM THE
GULF OF MEXICO FRIDAY TOWARD THE OUTER BANKS/VIRGINIA BEACH ON
SATURDAY MORNING. THE WESTWARD/FASTER TREND NOW BRINGS THE TRACK
OF THE LOW JUST OFFSHORE DURING THE DAY SATURDAY. A OVERALL
DECREASE IN THE ENSEMBLE SPREAD COMPARED TO PREVIOUS MODEL RUNS
LEADS TO LESS UNCERTAINTY THAN WITH PREVIOUS FORECAST UPDATES. THE
MAIN UNCERTAINTIES THAT STILL REMAIN ARE HOW FAR WEST THE
PRECIPITATION SHIELD WILL GET AND THE OVERALL THERMAL PROFILES.
THE 00Z NAM LOOKED TO BE A WARM/WEST RAINY OUTLIER BUT DID HAVE
SUPPORT FROM SEVERAL ECMWF ENSEMBLE MEMBERS BASED ON A LOOK AT THE
MEAN. ON THE OTHER SIDE THE 00Z GFS WAS FURTHER OFFSHORE JUST
GETTING THE PRECIPITATION SHIELD INTO THE POCONOS, A MAINLY SNOWY
OUTCOME PHL AND NW WITH MIX ALONG THE COAST. THE 00Z ECMWF WAS
SIMILAR BUT CHANGED THE 1-95 OVER TO RAIN LONGER.
IN TERMS OF WEATHER, DID INCREASE POPS TO LIKELY FROM PHL SE AND
HIGH CHANCE NORTH TO CAPTURE INCREASING CERTAINTY OF A STORM
IMPACTING US IN THIS PERIOD. WITH THIS IN MIND SNOW CHANCES WILL
BEGIN TO INCREASE FROM SOUTH TO NORTH FRIDAY NIGHT WITH AREAS FROM
PHL TO THE SE CHANGING TO RAIN FOR A WHILE ON SATURDAY WITH WAA.
THEN THE CCB COMES THROUGH WITH A CHANGE BACK TO SNOW. MOUNT
POCONO APPEARS TO BE THE NORTHWARD EXTEND OF THE DRY/SNOW LINE
ATTM. THE ALL SNOW/ MIX LINE RUNS ROUGHLY ALONG THE 1-95 CORRIDOR.
COASTAL SECTIONS STAY MAINLY RAIN AFTER STARTING AND ENDING AS A
FEW HOURS OF SNOW. WENT COOLER THAN THE ENSEMBLE AND MOS GUIDANCE
TOOLS SHOW GIVEN THE POTENTIAL FOR SOME DYNAMICAL/ EVAPORATIONAL
COOLING WITH PRECIPITATION. THIS DOES NOT LOOK TO BE AN ICING
EVENT, AS MID-LEVEL AND SURFACE TEMPERATURES SHOULD BE RATHER
CLOSE TO EACH OTHER THROUGHOUT. WITH THE DEVELOPING LOW GOING EAST
AND NORTHEAST OF US, NORTHWEST WINDS MAY INCREASE SOME IN THE
AFTERNOON AND EVENING WITH GUSTS UP TO 20 KNOTS ON LAND. TO MUCH
UNCERTAINTY IN THE QPF TO SUGGEST SNOWFALL ACCUMULATIONS ATTM.
OVERALL, A HIGH IMPACT STORM HAS THE POTENTIAL TO IMPACT THE
REGION IN THIS PERIOD. THE TRACK AND INTENSITY CAN STILL CHANGE
OVER THE UPCOMING DAYS, STAY TUNED.
SUNDAY: A TEMPORARY BREAK BETWEEN SYSTEMS WITH A MIX OF CLOUDS
AND SUN. TEMPERATURES COULD BE COOLER DUE TO SNOW COVER. WENT
COOLER THAN THE ENSEMBLE/ MEX GUIDANCE.
SUNDAY NIGHT THROUGH TUESDAY: ANOTHER SYSTEM DIVES SOUTHEAST INTO
THE OHIO VALLEY AND THEN TURNS UP THE EAST COAST. THIS LOOKS TO BE
ANOTHER SET-UP WHERE THE PRIMARY LOW TRANSFERS IT`S ENERGY TO A
COASTAL LOW. THERE IS A HIGHER DEGREE OF SPREAD IN THE ENSEMBLES
WITH THIS FEATURE IN JUST HOW MUCH IT CAN DIG ACROSS THE OH VALLEY
AND STRENGTHEN ONCE IT REACHES THE EAST COAST. FOR NOW CARRYING A
CHANCE OF SNOW ACROSS THE REGION WITH SOME MIX ACROSS THE COAST,
AS A COOLER AIR MASS MOVES IN. SNOW COVER WILL AGAIN PLAY A ROLE IN
TEMPERATURE FORECASTS BUT DID NOT AS COLD AS THE 00Z ECMWF WHICH
MAY BE THE OTHER EXTREME.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
THE TAFS BECOME IFR BY AFTERNOON ALL TERMINALS WITH THE SNOW.
THIS MORNING VFR WITH CIGS LOWERING TO STRATOCU LEVEL. LIGHT
NORTHEAST WINDS.
THIS AFTERNOON, QUICKLY BECOMING IFR WITH THE ONSET OF SNOW
ESTIMATED BETWEEN 17Z AND 20Z FOR MOST TERMINALS. GENERAL
DIRECTION OF MOVEMENT SOUTHWEST TO NORTHEAST. HEAVY ENOUGH SNOW
FOR ACCUMS ON TARMAC. THERE MAY BE SOME MIXED PCPN AT THE START AT
KMIV AND KACY. CIGS SHOULD ALSO LOWER TO IFR. NORTHEAST WINDS
SHOULD AVERAGE 5 TO 10 KNOTS.
THIS EVENING, CONDITIONS IMPROVING TO MVFR CIGS AS SNOW TAPERS
OFF AND ENDS. VSBYS SHOULD BE VFR ALL TERMINALS BY LATE EVENING.
NORTH WINDS WILL AVERAGE 5 TO 10 KNOTS.
OUTLOOK...
THURSDAY THROUGH FRIDAY NIGHT: VFR, DECREASING CLOUDS THURSDAY
AND INCREASING CLOUDS FRIDAY NIGHT.
SATURDAY AND SATURDAY NIGHT: MVFR AND IFR CEILINGS AND VSBYS IN
SNOW AND RAIN. MORE RAIN SOUTHEAST OF PHL AND SNOW NORTHWEST OF
PHL. NORTHWEST GUSTS UP TO 20 KNOTS SATURDAY AFTERNOON AND NIGHT.
SUNDAY: VFR.
SUNDAY NIGHT: INCREASING CLOUDS POTENTIAL MVFR CEILINGS LATE WITH
SNOW.
&&
.MARINE...
THE PREDICTED INTENSIFICATION OF THE CLIPPER LOW IS SLOW ENOUGH
THAT SMALL CRAFT ADVISORY WINDS AND SEAS ARE NOT EXPECTED TO BE
REACHED TODAY. STRONGEST WINDS SHOULD BE IN OUR SOUTHERN ATLANTIC
WATERS CLOSEST TO THE LOW. AS THE LOW MOVES FARTHER OFFSHORE
TONIGHT, WINDS WILL BECOME LIGHTER.
OUTLOOK...
THURSDAY THROUGH FRIDAY NIGHT: SUB SCA SEAS AND WINDS INCREASING
FRIDAY NIGHT.
SATURDAY AND SATURDAY NIGHT: SCA SEAS AND GUSTS BY AFTERNOON.
WINDS FROM THE EAST SHIFTING TO NORTHWEST BY SATURDAY NIGHT. SOME
GALE FORCE GUSTS POSSIBLE SATURDAY AFTERNOON AND NIGHT.
SUNDAY AND SUNDAY NIGHT: SEAS AND WIND GUSTS DECREASING BELOW SCA
CRITERIA BY SUNDAY AFTERNOON.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ071-103-104-106.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
PAZ060-070-101-102.
NJ...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
NJZ016>024-027.
DE...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
DEZ002.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
DEZ001.
MD...WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
MDZ015-019-020.
WINTER WEATHER ADVISORY UNTIL 10 PM EST THIS EVENING FOR
MDZ008-012.
MARINE...NONE.
&&
$$
SYNOPSIS...GAINES
NEAR TERM...IOVINO
SHORT TERM...GIGI
LONG TERM...GAINES
AVIATION...GAINES/GIGI
MARINE...GAINES/GIGI
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
230 PM EST WED JAN 21 2015
.SYNOPSIS...
18Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A OVERALL BENIGN WEATHER
PATTERN ACROSS MUCH OF THE CONUS. MUCH OF THE CONUS SITS UNDER A
VERY BROAD AND UNAMPLIFIED LONGWAVE TROUGH. JUST A COUPLE SHORTWAVE
IMPULSES ROTATING THROUGH THIS PARENT TROUGH. ONE PIECE OF ENERGY IS
ROTATING THROUGH THE OHIO VALLEY TOWARD THE MID-ATLANTIC
STATES...WHILE ANOTHER IS ROTATING THROUGH THE DESERT SOUTHWEST. IT
WILL BE THIS ENERGY OVER THE SOUTHWEST THAT EVENTUALLY EJECTS
EASTWARD TO GIVE US OUR NEXT SHOT AT SOME RAIN LATER FRIDAY AND
FRIDAY NIGHT.
CURRENTLY OVER THE SOUTHEASTERN CONUS WE FIND A ZONAL FLOW PATTERN
ALOFT WITH PLENTY OF MID/UPPER LEVEL DRY AIR AS SEEN ON WV IMAGERY.
THE MORNING 21/12Z KTBW SOUNDING PROFILE SAMPLED THIS UPPER LEVEL
ENVIRONMENT WELL...WITH A DRAMATIC DROP IN RELATIVE HUMIDITY ABOVE
700MB. AT THE SURFACE WE FIND HIGH PRESSURE CENTERED OVER THE
MID-SECTION OF THE COUNTRY...HOWEVER A RIDGE EXTENDS WELL TO THE
EAST AND SOUTHEAST FROM THIS HIGH CENTER...ALL THE WAY TO THE
EASTERN GULF OF MEXICO AND FLORIDA PENINSULA.
WITH HIGH PRESSURE AT THE SURFACE AND ZONAL AND DRY FLOW ALOFT...
THERE IS ESSENTIALLY NO FOCUS FOR SYNOPTIC LIFT ANYWHERE NEAR THE
FORECAST AREA. THEREFORE...OUR FORECAST WILL REMAIN DRY THE REST OF
TODAY WITH A MIX OF SUN AND FEW-SCT FAIR WEATHER CUMULUS. HIGH
TEMPERATURES ARE JUST ABOUT NOW AT THE DAILY HIGH RANGING FROM THE
LOWER/MIDDLE 70S NORTH TO THE UPPER 70S TO NEAR 80 SOUTH.
TEMPERATURES HAVE RECENTLY COME DOWN A FEW DEGREES NEAR THE COAST AS
WE HAVE SEEN A WEAK SEA-BREEZE DEVELOP AND TURN WINDS ONSHORE OFF
THE COOLER SHELF WATERS.
&&
.SHORT TERM (TONIGHT AND THURSDAY)...
TONIGHT AND THURSDAY THE DRY AND SEASONABLE WEATHER PATTERN
CONTINUES. HIGH PRESSURE WILL CONTINUE TO RIDGE IN FROM THE
NORTHWEST PROVIDING A LIGHT EAST TO NORTHEAST LOW LEVEL FLOW ACROSS
THE PENINSULA. LOW TEMPERATURES WILL GENERALLY RANGE FROM THE UPPER
40S TO LOWER 50S FOR THE NATURE COAST...TO THE MIDDLE AND UPPER 50S
TRAVELING FURTHER SOUTH. WHERE THE RIDGE IS STRONGEST OVER THE
NATURE COAST...A FEW SPOTS MAY BE ABLE TO DECOUPLE LATE TONIGHT AND
RADIATE DOWN BRIEFLY INTO THE LOWER/MIDDLE 40S. THESE COOLER
LOCATIONS WILL BE SPOTTY IN NATURE...BUT THOSE THAT DO DECOUPLE MAY
ALSO SEE A PERIOD OF FOG TOWARD DAWN THURSDAY MORNING.
WHILE OUR SENSIBLE WEATHER WILL STAY DRY AND QUIET ON THURSDAY...OUR
ATTENTION WILL BEGIN TO SHIFT TO THE SYSTEM EVOLVING TO OUR WEST.
SHORTWAVE ENERGY WILL BE EJECTING OUT OF THE SOUTHWEST AND ACROSS
THE SOUTHERN PLAINS ON THURSDAY...WITH AN EXPANDING AREA OF SHOWERS
AND STORMS ACROSS THE WESTERN GULF AND LOWER MS VALLEY BY LATE IN
THE DAY. IT WILL BE THIS SYSTEM THAT EVENTUALLY BRINGS US SOME
INCLEMENT WEATHER BY LATER FRIDAY. BEFORE THAT HAPPENS...THURSDAY
WILL START OUT WITH A MIX OF SUN AND CLOUDS WITH TEMPERATURES AGAIN
RISING INTO THE 70S ALL AREAS FOR THE AFTERNOON. THE LATER INTO
THURSDAY WE GET...THE POTENTIAL FOR HIGH CLOUDS TO FILTER THE SUN
ARRIVING FROM THE WEST INCREASES. GFS/ECMWF BOTH SHOW QUITE A BIT OF
HIGH LEVEL MOISTURE STREAMING WELL EAST OF THE MAIN SYSTEM AND
ARRIVING OVERHEAD FOR THE SECOND HALF OF THE DAY.
&&
.LONG TERM (THURSDAY NIGHT THROUGH NEXT WEDNESDAY)...
INITIALLY ALOFT A LONG WAVE TROUGH STRETCHES FROM THE GREAT LAKES TO
THE SOUTHERN HIGH PLAINS WHILE RELAXED WEST-SOUTHWEST FLOW WAS OVER
THE GULF OF MEXICO AND FL. AT THE SURFACE HIGH PRESSURE SPRAWLS FROM
THE CENTRAL AND SOUTHERN HIGH PLAINS TO THE OHIO VALLEY AND SPILLS
ACROSS THE MID-ATLANTIC AND SOUTHEAST U.S. COASTS. A WEAK TROUGH OFF
THE TX COAST HAS A WARM FRONTAL BOUNDARY REACHING EAST ACROSS THE
GULF TO FL.
FRI-SAT: THE LONG WAVE TROUGH SHARPENS AS IT TRACKS OVER THE
SOUTHERN PLAINS AND GULF COAST TO THE SOUTHEAST U.S. THE SURFACE
TROUGH DEEPENS INTO A LOW AND MOVES NORTHEASTWARD...ACROSS THE FL
PANHANDLE AND GA...TO THE MID-ATLANTIC COASTAL WATERS. THE BOUNDARY
THAT WAS ACROSS THE GULF AND FL LIFTS NORTHWARD EARLY IN THE PERIOD
AS A COLD FRONT TRAILING SOUTH FORM THE TROUGH/LOW SWEEPS ACROSS THE
GULF THEN FL. THE WARM FRONTAL BOUNDARY LIFTS ACROSS THE AREA INTO
NORTH FL DURING THE DAY WITH SLIGHT CHANCE TO LIKELY SHOWERS ALONG
WITH ISOLATED THUNDERSTORMS. THE GREATEST COVERAGE WILL BE IN
NORTHERN COUNTIES...RIGHT ALONG AND TO THE NORTH OF THE BOUNDARY.
THEN THE COLD FRONT PUSHES IN FROM THE WEST WITH LIKELY SHOWERS AND
ISOLATED THUNDERSTORMS AHEAD OF IT. THE BEST UPPER LEVEL DYNAMICS
CURRENTLY IS EXPECTED TO STAY NORTH OF THE AREA...LIMITING THE
THREAT OF ANY STRONG STORMS. THE COLD FRONT CROSSES SOUTHWEST FL IN
THE MORNING AND EXITS BY AFTERNOON WITH SLIGHT CHANCE TO LOW
CATEGORY CHANCE SHOWERS IN IT/S WAKE. TEMPERATURES RUNNING ABOVE
NORMAL FRI BEGIN TO TUMBLE SAT.
SUN-MON: THE TROUGH ROTATES OFF THE EASTERN SEABOARD AS A SHORT
WAVE TROUGH DROPS OUT OF THE CANADIAN PRAIRIES INTO THE UPPER OHIO
VALLEY...MAINTAINING TROUGHINESS ACROSS EASTERN AND PARTS OF THE
CENTRAL CONUS...WITH A ROBUST SURFACE REFLECTION IN THE CENTRAL
APPALACHIANS. CYCLONIC FLOW AROUND THIS SURFACE FEATURE DOMINATES
THE SOUTHEAST U.S. AND MUCH OF FL. HIGH PRESSURE BUILDS OUT OF THE
SOUTHERN PLAINS AND ACROSS THE GULF TOWARD FL. TEMPERATURES WILL
STAY BELOW NORMAL...ALTHOUGH WARMING SLIGHTLY FOR MON.
TUE-WED: THE OHIO VALLEY SHORT WAVE TROUGH ALONG WITH IT/S SURFACE
REFLECTION ROTATES OFF THE EASTERN SEABOARD WITH A FRONTAL
TROUGH...EMBEDDED WITHIN BROAD CYCLONIC FLOW...TREKKING THROUGH THE
EAST GULF AND ACROSS FL TUE. VERY LIMITED MOISTURE WITH THIS FRONT
ALONG WITH THE BEST UPPER LEVEL DYNAMICS THAT STAY WELL TO THE NORTH
WILL PRECLUDE SIGNIFICANT RAINFALL...WITH A DRY FORECAST. RIDGING
ALOFT MOVES FROM THE WEST TO THE CENTRAL CONUS AS SURFACE HIGH
PRESSURE ACROSS THE SOUTHERN PLAINS AND GULF COAST STATES SETTLES IN
OVER THE GULF AND FL. TEMPERATURES...STILL BELOW NORMAL...COOL DOWN
TUE THROUGH WED. THE FAR NORTH COULD SEE LOWS APPROACH FREEZING WED
MORNING.
&&
.AVIATION...
VFR CONDITIONS PREVAIL ACROSS WEST-CENTRAL AND SOUTHWEST FLORIDA
UNDER PARTLY TO MOSTLY SUNNY SKIES THIS AFTERNOON. EXPECT VFR
CONDITIONS TO CONTINUE THROUGH THE EVENING HOURS. SOME PATCHY FOG IS
POSSIBLE LATE TONIGHT OVER INLAND AREAS WITH KLAL AND KPGD POSSIBLY
SEEING A BRIEF PERIOD OF MVFR VIS IN THE FEW HOURS BEFORE
DAWN...HOWEVER NO SIGNIFICANT RESTRICTIONS ARE ANTICIPATED. ANY
PATCHY FOG BURNS OFF QUICKLY THURSDAY MORNING WITH VFR CONDITIONS
PREVAILING THROUGH THE DAYLIGHT HOURS.
&&
.MARINE...
WEAK HIGH PRESSURE WILL GRADUALLY MOVE OUT OF THE AREA THROUGH
THURSDAY AS LOW PRESSURE MOVES INTO THE WESTERN GULF. AS THIS AREA
OF LOW PRESSURE APPROACHES...WINDS AND SEAS WILL BEGIN TO BUILD
THURSDAY NIGHT AND FRIDAY TO NEAR EXERCISE CAUTION LEVELS OFFSHORE.
THE LOW WILL MOVE INTO NORTHERN FLORIDA FRIDAY NIGHT...WITH WINDS
AND SEAS EXPECTED TO INCREASE TO SMALL CRAFT ADVISORY LEVELS FRIDAY
NIGHT AND SATURDAY. CONDITIONS WILL BEGIN TO IMPROVE SATURDAY
NIGHT...WITH HIGH PRESSURE BUILDING INTO THE GULF FROM THE WEST ON
SUNDAY.
&&
.FIRE WEATHER...
HIGH PRESSURE WILL HOLD CONTROL OF THE REGION THROUGH THURSDAY
KEEPING OUR WEATHER DRY AND SEASONABLE. RELATIVE HUMIDITY LEVELS
WILL REMAIN ABOVE CRITICAL LEVELS AND NO SIGNIFICANT FIRE WEATHER
CONCERNS ARE ANTICIPATED. LOW PRESSURE WILL APPROACH NORTHERN
FLORIDA LATER FRIDAY WITH INCREASING CHANCES FOR RAIN...MAINLY TO
THE NORTH OF TAMPA. THIS SYSTEM WILL DRAG A COLD FRONT THROUGH THE
STATE FRIDAY NIGHT AND SATURDAY MORNING WITH A CHANCE FOR A FEW
SHOWERS ALONG IT. THE FRONT WILL EXIT THE REGION EARLY SATURDAY WITH
COOL AND DRY WEATHER EXPECTED FOR THE REMAINDER OF THE UPCOMING
WEEKEND.
FOG POTENTIAL...NO SIGNIFICANT FOG IS EXPECTED THROUGH THURSDAY
NIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 59 77 64 75 / 0 0 10 40
FMY 61 80 65 80 / 0 10 10 10
GIF 57 77 62 78 / 0 0 10 40
SRQ 58 78 65 77 / 0 10 10 30
BKV 50 77 62 76 / 0 0 10 50
SPG 61 76 65 75 / 0 0 10 40
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/FIRE WEATHER...MROCZKA
MARINE...FLEMING
LONG TERM...RUDE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1025 AM EST WED JAN 21 2015
.UPDATE (REST OF TODAY THROUGH THURSDAY)...
15Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS A OVERALL BENIGN WEATHER
PATTERN ACROSS MUCH OF THE CONUS. MUCH OF THE CONUS SITS UNDER A
VERY BROAD AND UNAMPLIFIED LONGWAVE TROUGH. JUST A COUPLE SHORTWAVE
IMPULSES ROTATING THROUGH THIS PARENT TROUGH. ONE PIECE OF ENERGY IS
ROTATING THROUGH THE OHIO VALLEY TOWARD THE MID-ATLANTIC
STATES...WHILE ANOTHER IS ROTATING THROUGH THE DESERT SOUTHWEST. IT
WILL BE THIS ENERGY OVER THE SOUTHWEST THAT EVENTUALLY EJECTS
EASTWARD TO GIVE US OUR NEXT SHOT AT SOME RAIN LATER FRIDAY AND
FRIDAY NIGHT.
CURRENTLY OVER THE SOUTHEASTERN CONUS WE FIND A ZONAL FLOW PATTERN
ALOFT WITH PLENTY OF MID/UPPER LEVEL DRY AIR AS SEEN ON WV IMAGERY.
THE MORNING 21/12Z KTBW SOUNDING PROFILE SAMPLED THIS UPPER LEVEL
ENVIRONMENT WELL...WITH A DRAMATIC DROP IN RELATIVE HUMIDITY ABOVE
700MB. AT THE SURFACE WE FIND HIGH PRESSURE CENTERED OVER THE
MID-SECTION OF THE COUNTRY...HOWEVER A RIDGE EXTENDS WELL TO THE
EAST AND SOUTHEAST FROM THIS HIGH CENTER...ALL THE WAY TO THE
EASTERN GULF OF MEXICO AND FLORIDA PENINSULA.
WITH HIGH PRESSURE AT THE SURFACE AND ZONAL AND DRY FLOW ALOFT...
THERE IS ESSENTIALLY NO FOCUS FOR SYNOPTIC LIFT ANYWHERE NEAR THE
FORECAST AREA. THEREFORE...OUR FORECAST WILL REMAIN DRY TODAY.
LOOKING AT NEAR 100% OF THE POSSIBLE SUNSHINE LATE THIS MORNING THAT
WILL GIVE WAY TO ONLY A FEW-SCT SHALLOW CUMULUS FIELD DURING THE
AFTERNOON AS DIURNAL MIXING INTERACTS WITH THE AVAILABLE MOISTURE IN
THE LOWER PORTION OF THE COLUMN. HIGH TEMPERATURES WILL BE QUITE
SEASONABLE WITH LOWER 70S NORTH TO MIDDLE 70S THROUGH THE I-4
CORRIDOR...AND MIDDLE TO UPPER 70S DOWN TOWARD FORT MYERS.
TONIGHT AND THURSDAY THE DRY AND SEASONABLE WEATHER PATTERN
CONTINUES. HIGH PRESSURE WILL CONTINUE TO RIDGE IN FROM THE
NORTHWEST PROVIDING A LIGHT EAST TO NORTHEAST LOW LEVEL FLOW ACROSS
THE PENINSULA. LOW TEMPERATURES WILL GENERALLY RANGE FROM THE UPPER
40S TO LOWER 50S FOR THE NATURE COAST...TO THE MIDDLE AND UPPER 50S
TRAVELING FURTHER SOUTH. WHERE THE RIDGE IS STRONGEST OVER THE
NATURE COAST...A FEW SPOTS MAY BE ABLE TO DECOUPLE LATE TONIGHT AND
RADIATE DOWN BRIEFLY INTO THE LOWER/MIDDLE 40S. THESE COOLER
LOCATIONS WILL BE SPOTTY IN NATURE...BUT THOSE THAT DO DECOUPLE MAY
ALSO SEE A PERIOD OF FOG TOWARD DAWN THURSDAY MORNING.
WHILE OUR SENSIBLE WEATHER WILL STAY DRY AND QUIET ON THURSDAY...OUR
ATTENTION WILL BEGIN TO SHIFT TO THE SYSTEM EVOLVING TO OUR WEST.
SHORTWAVE ENERGY WILL BE EJECTING OUT OF THE SOUTHWEST AND ACROSS
THE SOUTHERN PLAINS ON THURSDAY...WITH AN EXPANDING AREA OF SHOWERS
AND STORMS ACROSS THE WESTERN GULF AND LOWER MS VALLEY BY LATE IN
THE DAY. IT WILL BE THIS SYSTEM THAT EVENTUALLY BRINGS US SOME
INCLEMENT WEATHER BY LATER FRIDAY. BEFORE THAT HAPPENS...THURSDAY
WILL START OUT WITH A MIX OF SUN AND CLOUDS WITH TEMPERATURES AGAIN
RISING INTO THE 70S ALL AREAS FOR THE AFTERNOON. THE LATER INTO
THURSDAY WE GET...THE POTENTIAL FOR HIGH CLOUDS TO FILTER THE SUN
ARRIVING FROM THE WEST INCREASES. GFS/ECMWF BOTH SHOW QUITE A BIT OF
HIGH LEVEL MOISTURE STREAMING WELL EAST OF THE MAIN SYSTEM AND
ARRIVING OVERHEAD FOR THE SECOND HALF OF THE DAY.
ENJOY YOUR WEDNESDAY EVERYONE!
&&
.AVIATION...
VFR CONDITIONS PREVAIL ACROSS WEST-CENTRAL AND SOUTHWEST FLORIDA
UNDER MOSTLY SUNNY SKIES LATE THIS MORNING. EXPECT VFR CONDITIONS TO
CONTINUE WITH A SCT SHALLOW CUMULUS FIELD DEVELOPING FOR THE
AFTERNOON. SOME PATCHY FOG IS POSSIBLE LATE TONIGHT OVER INLAND
AREAS WITH KLAL AND KPGD POSSIBLY SEEING A BRIEF PERIOD OF MVFR VIS
IN THE FEW HOURS BEFORE DAWN...HOWEVER NO SIGNIFICANT RESTRICTIONS
ARE ANTICIPATED. ANY PATCHY FOG BURNS OFF QUICKLY THURSDAY MORNING
WITH VFR CONDITIONS PREVAILING THROUGH THE DAYLIGHT HOURS.
&&
.MARINE...
WINDS AND SEAS WILL REMAIN BELOW HEADLINES TODAY THROUGH THURSDAY.
CONDITIONS WILL THEN DETERIORATE BEGINNING THURSDAY NIGHT AS AN AREA
OF LOW PRESSURE DEVELOPS ALONG THE NORTHERN GULF COAST AND MOVES
NORTHEASTWARD...DRAGGING A COLD FRONT THROUGH THE WATERS FRIDAY
NIGHT WITH INCREASING RAIN CHANCES. BOTH WINDS AND SEAS WILL REMAIN
ELEVATED THROUGH SATURDAY BEFORE CONDITIONS IMPROVE ON SUNDAY AS
HIGH PRESSURE BUILDS IN OVER THE AREA.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 74 59 76 64 / 0 0 10 10
FMY 79 61 79 65 / 0 0 10 10
GIF 76 58 76 62 / 0 0 10 10
SRQ 75 58 77 64 / 0 0 10 10
BKV 76 51 76 60 / 0 0 10 10
SPG 74 61 75 65 / 0 0 10 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/AVIATION...MROCZKA
MARINE...DOUGHERTY
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1010 AM EST WED JAN 21 2015
.DISCUSSION...
LATEST RUC ANALYSIS SHOWS THE FL PENINSULA GAINING THE BACKSIDE OF A
BROAD SFC/LOW LVL TROF THANKS TO A STRONG ZONAL JET THAT DOMINATES
THE WX PATTERN FROM THE CNTRL/SRN PLAINS TO THE SE COAST. MRNG
SOUNDINGS SHOW PWAT VALUES ARND 0.8" ACRS N FL...ARND 0.9" ACRS
CENTRAL FL...AND ARND 1.2" OVER S FL. DEEP W/NWRLY FLOW AT ALL SITES
WILL MAINTAIN THIS STRIATED MOISTURE DISTRIBUTION AS UPSTREAM
H100-H70 AND H85-H50 MEAN RH VALUES SHOW LITTLE VARIANCE OVER THE
ERN GOMEX.
A CONTINENTAL RIDGE WILL BUILD INTO THE DEEP SOUTH BEHIND THE
DEPARTING TROF...RESULTING IN A CONTINUED DRY/STABLE WX. SOURCE
REGION FOR THE AIRMASS IS WELL BLO THE 40TH PARALLEL...SO DESPITE A
LIGHT NRLY BREEZE...NO SIG COOLING WILL OCCUR. IN FACT...WITH NEAR
FULL SUN AND LIGHT WINDS THRU MIDDAY...AFTN MAX TEMPS ARE EXPECTED
TO REACH THE L/M70S WITH U70S PSBL E OF LAKE OKEECHOBEE...OVERALL
ABOUT 3-5F DEGS ABV CLIMO AVG.
MRNG FCST PACKAGE LOOKS FINE...ANY CHANGES WOULD BE LARGELY
TRANSPARENT. NO UPDATES NECESSARY.
&&
.AVIATION...THRU 22/12Z
SFC WINDS: THRU 22/00Z...N/NE 5-9KTS BCMG E/NE. AFT 22/00Z...N/NE
AOB 5KTS.
VSBYS/WX: THRU 22/06Z...VFR. AFT 22/06Z...PTCHY MVFR/LCL IFR IN
BR/HZ.
CIGS: VFR. THRU 22/00Z...N OF KMLB-KISM BTWN FL060-080.
&&
.MARINE...
BROAD LOW PRES TROF OVER THE WRN ATLC WILL PUSH E...ALLOWING A SFC
RIDGE OVER THE MS VALLEY TO NOSE INTO THE DEEP SOUTH. LIGHT TO
GENTLE W/NW SFC/BNDRY LYR BREEZE BCMG N/NE THRU LATE AFTN...THEN
CONTG OVERNIGHT. SEAS AOB 2FT. NO SIG CHANGES NECESSARY WITH THE
MRNG UPDATE.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...LASCODY
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
526 PM CST THU JAN 22 2015
.UPDATE...
ISSUED AT 524 PM CST THU JAN 22 2015
BASED ON THE CURRENT RATE OF THE EASTWARD PROGRESSION OF THE BACK
EDGE OF THE STRATUS IN WESTERN IA...AND TRENDS OF THE HRRR AND RAP
THAT A DECENT HANDLE ON THESE FEATURES...CLEARING WILL LIKELY TAKE
LONGER THAN ORIGINALLY EXPECTED. HAVE UPDATED THE FORECAST FOR THE
CLEARING TO REACH OUR WESTERN FORECAST AREA BORDER AROUND
MIDNIGHT...THEN CROSS THE MS RIVER AROUND 5 AM. THIS WOULD LEAVE
OUR ILLINOIS ZONES UNDER CLOUD COVER THROUGH THE NIGHT. FOR
NOW...HAVE MADE ONLY MINOR TWEAKS TO HOURLY TEMPERATURES...BUT
WILL NEED TO REASSESS FOR POSSIBLE WARMER LOWS WITH THE MORE
PERSISTENT CLOUD COVER.
&&
.SYNOPSIS...
ISSUED AT 346 PM CST THU JAN 22 2015
UPPER LEVEL TROUGH ALONG WITH A STRENGTHENING INVERSION AT 900 MB
TRAPPING THE LOW LEVEL MOISTURE BELOW...DESPITE SURFACE HIGH
PRESSURE OVER THE CWA. THIS HAS RESULTED IN AN EXTENSIVE AREA OF
STRATUS TODAY ACROSS THE CWA. 3 PM TEMPERATURES RANGED FROM THE
UPPER 20S TO MID 30S.
ELSEWHERE...SUBSIDENCE BEHIND THE DEPARTING TROUGH WAS CLEARING
THE SKIES IN WISCONSIN AND ALSO WESTERN IA/WESTERN MN. HOWEVER...THE
CLEARING HAS COME TO A GRINDING HALT IN SOUTHERN WI BUT CONTINUES
TO MAKE SLOW BUT STEADY PROGRESS EASTWARD IN WESTERN IA.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 346 PM CST THU JAN 22 2015
FORECAST FOCUS ON CLOUDS AND TEMPERATURES. WARMER ON FRIDAY.
TONIGHT...GRADUAL CLEARING FROM WEST TO EAST AS THE UPPER TROUGH
SHIFTS EAST AND THE FLOW BECOMES ANTI-CYCLONIC. THE SURFACE RIDGE
WILL BE SHIFTING TO OUR SOUTH ALLOWING WINDS TO BACK SOUTHWEST.
TEMPERATURES SHOULDN`T DROP TOO MUCH TONIGHT DUE TO SOUTHWEST WINDS
AND WEAK WARM AIR ADVECTION DEVELOPING. MINIMUM TEMPERATURES ARE
EXPECTED TO BE IN THE LOWER TO MID 20S...WITH THE COOLEST READINGS
IN FAR NW IL WHERE SEVERAL INCHES OF SNOW COVER EXISTS.
FRIDAY...SKIES WILL BE SUNNY IN THE MORNING THEN INCREASING CLOUDS
DURING THE AFTERNOON IN OUR NORTH...AS A WEAK SHORT WAVE DROPS
SOUTHEAST TOWARDS THE AREA IN THE NW FLOW ALOFT. WITH SOUTHWEST SURFACE
WINDS THIS SHOULD BOOST AFTERNOON TEMPERATURES INTO THE UPPER 30S
TO LOWER 40S AT MOST LOCATIONS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 335 PM CST THU JAN 22 2015
CHANCE OF RAIN/SNOW LATE SAT NGT-SUN...OTHERWISE GENERALLY DRY WITH
TEMP MOSTLY NEAR TO ABOVE NORMAL.
FRIDAY NIGHT... WEAK AND QUICK MOVING UPPER AIR DISTURBANCE TO SWEEP
THROUGH THE GREAT LAKES WITH ATTENDANT SURFACE TROUGH PASSING
ACROSS CWA. WEAK FORCING AND LIMITED MOISTURE SHOULD PRECLUDE MUCH
MORE THAN JUST INCREASING CLOUDS AND POSSIBLY FEW FLURRIES OR PATCHY
DRIZZLE NORTHEAST IA INTO NORTHWEST IL DEPENDING ON ICE INTRODUCTION
AND DEPTH OF MOISTURE. MINIMAL COOLING POST TROUGH COUPLED WITH
CLOUDINESS LENDS SUPPORT FOR STAYING NEAR WARM SIDE OF GUIDANCE ON
LOWS AND GENERALLY IN THE UPPER 20S TO AROUND 30F.
SATURDAY AND SUNDAY... MODELS STILL VARY WITH TRACK OF FAIRLY VIGOROUS
CLIPPER SYSTEM LATE SATURDAY NIGHT ALTHOUGH STARTING TO SEE SOME
TRENDS AND CLUSTERING WITH 12Z MODEL SUITE. MOST NOTABLY THE GEM HAS
TRENDED MUCH FURTHER SOUTH FROM UPPER PENINSULA OF MI TO CENTRAL WI WHICH
IS CLOSER TO TRACK OF UKMET AND OPERATIONAL GFS. THE OPERATIONAL GFS IS
ACTUALLY A LITTLE FURTHER SOUTH OF ENSEMBLE MEAN AND NEARLY ALL OF THE
MEMBERS. MEANWHILE THE ECMWF CONTINUES TO REMAIN THE FURTHEST SOUTH TAKING
THE CLIPPER SYSTEM ACROSS THE CWA. A MORE NORTHEAST TRACK WOULD RESULT
IN TAPERED PCPN CHCS FROM WEST TO EAST WITH RAIN BEING THE MORE DOMINANT
PRECIPITATION TYPE WITH SOME LIGHT SNOW OR FLURRIES POSSIBLE IN
WRAP-AROUND. MEANWHILE A TRACK FURTHER SOUTHWEST SUCH AS SHOWN BY ECMWF
COULD RESULT IN MORE SNOW WITH LIGHT ACCUMULATIONS. WITH THE MAIN SYSTEM
IN QUESTION STILL OFF THE BRITISH COLUMBIA COASTLINE AND NOT WELL SAMPLED
YET BY RAOB NETWORK IT COULD TAKE ANOTHER 12-24 HRS BEFORE THAT OCCURS AND
BEFORE WE START SEEING BETTER MODEL CONSISTENCY WITH THE TRACK. FOR NOW
THOUGH WILL CONTINUE WITH CHANCE OF PCPN OVERNIGHT SATURDAY NIGHT
THROUGH SUNDAY... WITH MAINLY RAIN WITH SOME MIX OF SNOW NORTH TRANSITIONING
TO MIX OR SNOW SUNDAY. FEELING IS A MORE SOUTHERLY TRACK PERHAPS CLOSER
TO ECMWF OR BLENDED WITH GFS REASONABLE. AS PREVIOUS SHIFTS HAVE MENTIONED
THE ORIENTATION OF THE LEFT EXIT REGION OF 150+ KT JET WITH COMPACT
SHORTWAVE TROUGH FAVORS MORE DIGGING OF SYSTEM WHICH FITS CONCEPTUALLY WITH
SYSTEM ENTERING LONGWAVE TROUGH. THIS WOULD SUPPORT MORE SOUTHERLY TRACK
WHICH IS ALSO HINTED BY GFS ENSEMBLE WITH ITS LARGEST STANDARD DEVIATION
IN 500 MB HEIGHTS OVER EASTERN IA/NORTHWEST IL SUNDAY 12Z.
TEMPS SATURDAY AND SUNDAY WILL DEPEND ON TRACK OF CLIPPER SYSTEM... BUT
IN GENERAL MUCH OF THE PERIOD SHOULD BE ABOVE FREEZING AND ABOVE NORMAL
WITH AREA RESIDING IN WARM SECTOR AHEAD OF SYSTEM. EXCEPTION BEING
SUNDAY NIGHT IN WAKE OF DEPARTING SYSTEM AS NORTHERLY WINDS WILL USHER IN
COLDER AIR AND EXPECT LOWS SUNDAY NIGHT TO DIP DOWN WELL INTO THE 20S.
MONDAY THROUGH THURSDAY... MAINLY DRY WITH SOME SUGGESTION OF ANOTHER
CLIPPER SYSTEM AROUND TUESDAY AND POSSIBLY THURSDAY BUT CONFIDENCE ON
TRACK AND IMPACT TOO LOW FOR MENTIONABLE POPS AS IT APPEARS AT THIS TIME.
TEMPS TO TAKE A BIT OF A HIT MONDAY INTO TUESDAY WITH COLDER AIR AND
MAY NEED TO BE LOWERED A BIT MORE CLOSER TO NORMAL WITH ECMWF AND GFS
SHOWING 850 TEMPS AROUND -4C TO -10C FROM WEST TO EAST SUPPORTIVE OF
GRADIENT IN TEMPS AS WELL. ANOTHER ROUND OF MP AIRMASS SHOWN BY GFS AND
ECMWF TO RETURN TO MIDWEST MID-LATE WEEK WHICH SHOULD SEND TEMPS BACK
ABOVE NORMAL.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 524 PM CST THU JAN 22 2015
STRATUS WITH CIGS AROUND 1200 TO 2000 FT AGL...RESULTING IN
WIDESPREAD MVFR CONDITIONS...WILL BE VERY SLOW TO CLEAR OUT
OVERNIGHT. THE UPDATED FORECASTS HAVE DELAYED THE CLEARING TREND
BY SEVERAL HOURS. CONFIDENCE IN THE TIMING OF THIS CONVERSION TO
VFR IS BELOW AVERAGE AND THERE IS A POTENTIAL FOR FOG DEVELOPMENT
AROUND THE TIME OF THE CLEARING...WHICH COULD PERSIST INTO THE
HOURS AROUND DAWN...WHICH HAS NOT BEEN INCLUDED IN THE LATEST
FORECASTS. CONDITIONS ARE EXPECTED TO BE VFR DURING THE DAY FRIDAY
WITH WINDS BECOMING GUSTY AT MOST SITES FROM THE SOUTHWEST.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...SHEETS
SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...05
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS GOODLAND KS
930 PM MST TUE JAN 20 2015
.SHORT TERM...(THIS AFTERNOON THROUGH WEDNESDAY)
ISSUED AT 139 PM MST TUE JAN 20 2015
EARLY AFTERNOON WV IMAGERY AND RAP UPPER LEVEL ANALYSIS SHOWS NW
FLOW IN PLACE FROM THE CANADIAN ROCKIES AND INTO THE SOUTHERN
PLAINS. SHORTWAVE TROUGH AXIS FROM LAST NIGH HAS SHIFTED
EAST..WITH UPSTREAM THERE IS ANOTHER WEAK SHORTWAVE IN THE
NORTHERN STREAM OVER ALBERTA CANADA. IN THE SOUTHERN STREAM A
STRONGER SHORTWAVE TROUGH IS MOVING ONSHORE OVER SOUTHERN
CALIFORNIA.
THIS AFTERNOON...LOW TO MID CLOUD SHIELD ASSOCIATED WITH DECAYED
PRECIPITATION BAND HAS SHIFTED SOUTH. 950-850 MB THETA E LAPSE
RATES INDICATE SHALLOW UNSTABLE LAYER THAT HAS LED A FEW POCKETS
OF SPRINKLES DEVELOPING OVER EASTERN WYOMING/NORTHEAST
COLORADO...WHICH IS CURRENTLY TRANSITIONING SOUTH AND EAST. THIS
WILL BE TIED TO DAYTIME HEATING AND I DO NOT ANTICIPATE ANY
MEASURABLE PRECIP WITH THIS ACTIVITY.
TONIGHT-WEDNESDAY...NORTHERN AND SOUTHERN STREAM SHORTWAVE TROUGHS
WILL MERGE AND DEEPEN LATE TONIGHT WITH NOSE OF H3 JET SLIDING
OVER EASTERN COLORADO/NORTHWEST KANSAS. AS THIS UPPER LOW DEEPENS
BETTER FORCING WILL MAINLY BE OVER EASTERN COLORADO...LIKELY
SOUTHWEST OF OUR CWA. DESPITE THIS...THERE SHOULD BE ENOUGH
FORCING FOR LIGHT SNOW DEVELOPMENT ACROSS THE SOUTHWEST PORTIONS
OF OUR CWA...WITH BEST CHANCES IN THE 12Z-20Z TIME FRAME. I COULD
SEE AROUND ONE INCH OF SNOW ACCUMULATIONS OVER WESTERN PARTS OF
KIT CARSON AND CHEYENNE COUNTIES IN COLORADO...WITH LESS THAN ONE
INCH FURTHER EAST. ALTHOUGH THERE IS AN OVERLAPPING PRECIP SIGNAL
FURTHER NORTHEAST INTO NORTHWEST KANSAS...TRACK OF MAIN UPPER LOW
AND POSITION OF UPPER LEVEL DIVERGENCE LOWERS CONFIDENCE IN LIGHT
SNOW OVER NW KANSAS. I TAPERED POPS TO THE NORTHEAST IN LINE WITH
CONSENSUS...WITH AND HAVE ACTIVITY WINDING DOWN DURING THE
AFTERNOON AS UPPER LEVEL FORCING SHIFTS SOUTH.
TEMP FORECAST WED MAY BE ON THE COLDER SIDE AS H85 TEMPS AROUND -4C
RANGE ARE ADVERTISED BY MOST GUIDANCE. WITH CLOUD COVER/PRECIP IN
THE WEST THROUGH THE EARLY AFTERNOON WE MAY NOT SEE MUCH WARMING
AT ALL...AND TEMPS HOVERING AROUND OR BELOW FREEZING. IN THE EAST
WE MAY SEE SOME BREAKS IN CLOUD COVER BY THE AFTERNOON...WHICH
COULD ALLOW TEMPS TO RECOVER INTO THE LOW 40S. NOT AN EASY TEMP
FORECAST AS POSITION OF PRECIP/CLOUD COVER WILL DETERMINE CUTOFF
IN SUB FREEZING HIGHS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 1239 PM MST TUE JAN 20 2015
PRECIPITATION SHOULD END BY 00Z THURSDAY AS SHORTWAVE TROUGH
CONTINUES TO MOVE SOUTH. SHORTWAVE RIDGING WILL FOLLOW ON THURSDAY
WITH DRY CONDITIONS AND TEMPERATURES NEAR NORMAL. NORTHWEST FLOW
WILL RETURN ON FRIDAY AND CONTINUE THROUGH THE WEEKEND WITH A
COUPLE OF EMBEDDED WEAK DISTURBANCES. ONE MOVES THROUGH ON FRIDAY
BUT WILL LACK ADEQUATE LOW LEVEL MOISTURE FOR MORE THAN A FEW
AFTERNOON SPRINKLES AS TEMPERATURES WARM TO THE LOWER 50S. ANOTHER
STRONGER SYSTEM WILL MOVE THROUGH THE NORTHERN PLAINS AND UPPER
MISSISSIPPI RIVER VALLEY SATURDAY NIGHT AND SUNDAY. THE UPPER
DYNAMICS WILL BE TOO FAR AWAY FOR PRECIPITATION CHANCES...THOUGH
IT WILL CREATE A TIGHT HEIGHT AND PRESSURE GRADIENT FOR WINDY
CONDITIONS ON SUNDAY ESPECIALLY IN EASTERN SECTIONS OF THE LOCAL
AREA LIKE MCCOOK AND HILL CITY. AN UPPER RIDGE WILL BUILD WEST
ACROSS THE ROCKIES AND ADJACENT PLAINS EARLY NEXT WEEK RESULTING
IN DRY CONDITIONS AND MUCH ABOVE NORMAL TEMPERATURES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 930 PM MST TUE JAN 20 2015
KGLD...VFR EXPECTED THROUGH THE PERIOD WITH NORTH OR NORTHWEST
WINDS UNDER 10KTS THROUGH 15Z AND AFTER 00Z WITH CLOSE TO 12KT
WINDS FROM 18Z THROUGH 23Z. VFR SKY CONDITIONS EXPECTED BUT WILL
NEED TO WATCH THE 15Z-23Z TIMEFRAME AS SCT POSSIBLY BKN MVFR
CLOUDS MOVE IN FROM THE SOUTHWEST. A FEW SNOW SHOWERS ALSO
POSSIBLE AROUND THE TERMINAL DURING THE TIME OF LOWER CLOUDS.
KMCK...VFR EXPECTED THROUGH THE PERIOD WITH NORTH OR NORTHWEST WINDS
10KTS OR LESS THROUGH THE PERIOD. VFR CIGS EXPECTED BUT WILL NEED
TO WATCH A FEW HOURS EITHER SIDE OF 00Z (THURSDAY) AS MVFR CLOUDS
POSSIBLY MOVE IN FROM THE NORTHWEST.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...024
AVIATION...99
AREA FORECAST DISCUSSION
NWS PADUCAH KY
951 PM CST Thu Jan 22 2015
.UPDATE...
Issued at 951 PM CST THU JAN 22 2015
The latest HRRR and the 00Z NAM bring light precipitation right to
the TN border areas around 12Z. Decided to spread the slight
chance PoPs a bit farther north at that time, just to give it a
bit wider berth. A look at 18Z GFS and 00Z NAM soundings near KHOP
indicate that the column should be cool enough for snow. The only
potential issue is whether the saturation and lift will be deep
enough to actually have active ice nucleation. With a persistent
northeast wind and thickening cloud cover in that area overnight,
surface temperatures should remain just above freezing. Added a
slight chance of light snow in those areas to go along with the
light rain previously mentioned through the morning hours Friday.
Accumulations still look doubtful through the morning hours.
UPDATE Issued at 636 PM CST Thu Jan 22 2015
Updated aviation discussion only.
&&
.SHORT TERM...(Tonight through Saturday night)
Issued at 210 PM CST THU JAN 22 2015
Forecast confidence is increasing that the system brushing our
south/east areas Friday aftn/Friday evening should NOT pose much of
an impact to our forecast area. Models are in decent agreement now
with both the qpf and thermal fields over the southern Pennyrile
region of western KY. This looks to be a high POP/low qpf
event...and will likely be mostly on the liquid side...esp
during the day Friday. Even if weak cold air advection aloft can
switch the precip to light snow early in the evening, sfc temps
should remain above freezing until the precip comes to an end
before midnight.
Not much cold air to follow either. In fact, winds will become
more westerly, then southwesterly Sat/Sat night as a clipper
system drops se into the western Great Lakes region. Most
locations will top out in the mid to upper 40s Saturday
afternoon.
.LONG TERM...(Sunday through Thursday)
Issued at 210 PM CST THU JAN 22 2015
There is very little change in the long term forecast. A
clipper type low pressure system will move southeast across the
Great Lakes region Sunday and Sunday night, possibly bringing a
little rain or mixed rain and snow. Dry and colder weather is
expected Monday through Wednesday, followed by milder southwest
winds ahead of the next front Thursday.
As far as the daily details...
On Sunday...expect a southwest wind flow of milder air ahead of a
cold front moving southeast across Illinois and Missouri. Some light
rain showers are possible ahead of the front as a 500 mb shortwave
brushes past our region. Higher qpf will likely be confined to areas
near the shortwave trough over the upper Ohio Valley and Great Lakes
region.
On Sunday night...winds will shift into the northwest with the
passage of the surface front. Any lingering precip could end as
light snow showers late at night.
Monday through Tuesday will be dry and colder. The 12z gfs mos high
temps appear too warm considering the gfs has 850 mb temps around
minus 5. The colder ecmwf mos appears more reasonable. Either way,
there will be a decent temp gradient from northeast to southwest
across our region. Highs both days should be about 10 degrees colder
over southwest Indiana than the Ozark foothills. Expect enough
cloudiness to keep highs mainly in the upper 30s in southwest
Indiana. There should be more sun over Missouri, which should allow
temps to reach the upper 40s there.
On Wednesday...high pressure will be located over the Ohio Valley,
bringing dry conditions with highs in the 40s.
On Thursday...rather gusty southwest winds are expected ahead of a
strong cold front approaching the Lower Ohio Valley. Except for the
12z ecmwf, the models indicate moisture will be too limited for
pre-frontal showers. This forecast will be dry for Thursday.
&&
.AVIATION...
Issued at 636 PM CST THU JAN 22 2015
MVFR decks may affect some airports across swrn IN and adjacent srn
IL for the evening, otherwise VFR cigs are expected. A light nrly
sfc wind will prevail. The KPAH TAF may be affected by pcpn late in
the period. For now the TAF has light snow after 20Z but this may
start as rain. Further adjustments will be made for the 06Z TAFs.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...MEFFERT
LONG TERM...MY
AVIATION...DB
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
950 PM CST THU JAN 22 2015
.DISCUSSION...
REGIONAL 88DS SHOW THE BULK OF THE MODERATE/HEAVY RAINS NOW
PUSHING EAST OF THE FORECAST AREA..WITH MAYBE THE LOWER ACADIANA
ZONES STILL SEEING A LITTLE BIT OF HEAVIER PRECIP. ALL THIS WILL
CONTINUE PUSHING EWD ALONG WITH THE SFC LOW OVER THE NRN GULF...
NOW LOCATED SE OF CAMERON. BEHIND THE LARGE AREA OF RAIN REGIONAL
88DS SHOW JUST SPORADIC PATCHY LIGHT RAIN...ALTHOUGH IT CAN
CERTAINLY BE ASSUMED THAT AREAS OF DRIZZLE ARE OCCURRING WITHIN
SUCH AN EXPANSIVE STRATUS OVERCAST NOTED IN SFC OBS ACROSS THE
REGION AHEAD OF THE APPROACHING STORM SYSTEM ALOFT NOW MOVING INTO
WRN TX. BASED ON ALL THIS LOWERED POPS SOMEWHAT FOR THE REMAINDER
OF THE NIGHT...ALTHOUGH RETAINED CATEGORICAL POPS FOR THE SERN
ZONES THROUGH MIDNIGHT. ELSEWHERE JUST MINOR TWEAKS AT MOST TO THE
INHERITED GRIDS/ZONES.
UPDATE OUT SHORTLY.
25
&&
.PREV DISCUSSION... /ISSUED 547 PM CST THU JAN 22 2015/
AVIATION...RAIN WITH GUSTY WINDS AND IFR CONDITIONS CAN BE
EXPECTED TO CONTINUE FOR THE WESTERN TERMINALS BPT, LCH AND AEX.
IFR DUE TO VIS AT TIMES AT ARA AND LFT WITH PREDOMINANT MVFR.
ALL THIS DUE TO THE FRONTAL WAVE CURRENTLY APPROACHING THE UPPER
TEXAS COAST WITH A TIGHT GRADIENT PRODUCING GUSTY NORTHEAST WINDS.
RAIN SHOULD TAPER OFF TO VCSH AROUND MID MORNING FRIDAY AND END ABOUT
SUNDOWN FRIDAY WITH VFR AS THE FRONTAL WAVE PULLS UP THE EASTERN
SEABOAARD AND DRY AIR MOVES IN FROM THE NORTHWEST.
SWEENEY
PREV DISCUSSION... /ISSUED 317 PM CST THU JAN 22 2015/
DISCUSSION...
BROAD AREA OF RAIN COVERING OUR ENTIRE COUNTY WARNING AREA THIS
AFTERNOON. TEMPERATURES NOW HOVERING IN THE MID 40S TO LOWER 50S.
OUR 100 PERCENT POP FORECAST LOOKING RIGHT ON THE MONEY...SO A JOB
WELL DONE TO OUR STAFF.
ON THE LARGER CANVAS...IN THE UPPER LEVELS...A TROUGH OF LOW
PRESSURE IS CURRENTLY WORKING ACROSS WEST TEXAS WITH AN ABUNDANCE OF
ENERGY RIDING THROUGH OUR AREA AT THE MOMENT. THIS HAS SPAWNED AN
ELONGATED AREA OF SURFACE LOW PRESSURE OFF THE TEXAS OFFSHORE COASTAL
WATERS FROM BAFFIN BAY TO GALVESTON. MASSIVE AMOUNTS OF GULF
MOISTURE TRAPPED ALONG THE SOUTHEAST TEXAS & LOUISIANA COASTAL
WATERS IN A VERY RICH CONVERGENCE ZONE WHERE LARGE SWATHS OF RAIN
ARE BEING CREATED AND THEN MOVED INLAND.
OBVIOUSLY...THIS IS GOING TO CREATE A VERY GENEROUS AMOUNT OF 1 1/2
TO 2 INCH RAIN AMOUNTS WITH ISOLATED AMOUNTS UP TO THREE INCHES. THE RAIN
WILL BE HERE TO STAY THROUGH THE NIGHT AS OUR HRRR & GFS MODELS
SHOWING OUR NEWLY BORN SURFACE LOW MOVING WEST TO EAST ACROSS OUR
NORTHWEST GULF OF MEXICO THROUGH EARLY MORNING FRIDAY. I RAISED THE
WIND ADVISORY TODAY THROUGH MIDNIGHT FOR I-10 CORRIDOR SOUTH
BECAUSE THIS SURFACE LOW WILL TIGHTEN UP THE WIND FIELD ACROSS OUR
COASTAL AREAS WITH SOME GUSTS AT TIMES FURTHER NORTH AT LEAST
UNTIL MIDNIGHT.
SO...ELEVATED WINDS ARE GOING TO BE A PROBLEM UNTIL MIDNIGHT ALONG
THE COASTAL AREAS AND THE RAINS ARE GOING TO BE THE BIGGEST
PROBLEMS FOR THE ENTIRE AREA OVER THE NEXT 24 HOURS. THE SURFACE
LOW WILL MOVE EAST OF OUR AREA BY NOON FRIDAY...HOWEVER WE WILL
CONTINUE TO EXPECT LIGHT RAIN OR SHOWERS THROUGH THE AFTERNOON
FRIDAY AS THE UPPER LEVEL SYSTEM TRACKS EVEN CLOSER TO US.
RAIN SHOULD EXIT THE ENTIRE AREA BY FRIDAY NIGHT WITH HIGH
PRESSURE BUILDING BACK INTO THE AREA. THE REST OF THE FORECAST
THROUGH DAY SEVEN LOOKS DRY WITH COOL TEMPERATURES THROUGH SUNDAY
MORNING WITH A SLOW WARM-UP FOR THE REST OF NEXT WEEK.
MARINE...
SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT UNTIL 6 PM FRIDAY AS SOUTHEAST
FLOW THIS AFTERNOON TRANSITIONS TO A NORTHERLY FLOW LATER TONIGHT
WITH THE PASSAGE OF A NORTHWEST GULF SURFACE LOW.
06
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 44 48 37 57 39 / 100 30 20 10 0
KBPT 44 49 37 58 40 / 100 30 10 0 0
KAEX 41 45 34 56 36 / 100 40 20 0 0
KLFT 46 48 38 56 39 / 100 30 20 10 0
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE FOLLOWING
ZONES: ACADIA...CALCASIEU...EAST CAMERON...IBERIA...
JEFFERSON DAVIS...LAFAYETTE...LOWER ST. MARTIN...ST. MARY...
UPPER ST. MARTIN...VERMILION...WEST CAMERON.
TX...WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE FOLLOWING
ZONES: JEFFERSON...ORANGE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST FRIDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM CAMERON LA TO HIGH ISLAND TX OUT
20 NM...COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON LA
OUT 20 NM...COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO
INTRACOASTAL CITY LA OUT 20 NM...WATERS FROM INTRACOASTAL
CITY TO CAMERON LA FROM 20 TO 60 NM...WATERS FROM CAMERON
LA TO HIGH ISLAND TX FROM 20 TO 60 NM...WATERS FROM LOWER
ATCHAFALAYA RIVER TO INTRACOASTAL CITY LA FROM 20 TO 60 NM.
SMALL CRAFT EXERCISE CAUTION UNTIL MIDNIGHT CST TONIGHT FOR THE
FOLLOWING ZONES: CALCASIEU LAKE...SABINE LAKE...VERMILION
BAY.
&&
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSLAKECHARLES
WWW.TWITTER.COM/NWSLAKECHARLES
WWW.YOUTUBE.COM/NWSLAKECHARLES
&&
$$
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
547 PM CST THU JAN 22 2015
.AVIATION...RAIN WITH GUSTY WINDS AND IFR CONDITIONS CAN BE
EXPECTED TO CONTINUE FOR THE WESTERN TERMINALS BPT, LCH AND AEX.
IFR DUE TO VIS AT TIMES AT ARA AND LFT WITH PREDOMINANT MVFR.
ALL THIS DUE TO THE FRONTAL WAVE CURRENTLY APPROACHING THE UPPER
TEXAS COAST WITH A TIGHT GRADIENT PRODUCING GUSTY NORTHEAST WINDS.
RAIN SHOULD TAPER OFF TO VCSH AROUND MID MORNING FRIDAY AND END ABOUT
SUNDOWN FRIDAY WITH VFR AS THE FRONTAL WAVE PULLS UP THE EASTERN
SEABOAARD AND DRY AIR MOVES IN FROM THE NORTHWEST.
SWEENEY
&&
.PREV DISCUSSION... /ISSUED 317 PM CST THU JAN 22 2015/
DISCUSSION...
BROAD AREA OF RAIN COVERING OUR ENTIRE COUNTY WARNING AREA THIS
AFTERNOON. TEMPERATURES NOW HOVERING IN THE MID 40S TO LOWER 50S.
OUR 100 PERCENT POP FORECAST LOOKING RIGHT ON THE MONEY...SO A JOB
WELL DONE TO OUR STAFF.
ON THE LARGER CANVAS...IN THE UPPER LEVELS...A TROUGH OF LOW
PRESSURE IS CURRENTLY WORKING ACROSS WEST TEXAS WITH AN ABUNDANCE OF
ENERGY RIDING THROUGH OUR AREA AT THE MOMENT. THIS HAS SPAWNED AN
ELONGATED AREA OF SURFACE LOW PRESSURE OFF THE TEXAS OFFSHORE COASTAL
WATERS FROM BAFFIN BAY TO GALVESTON. MASSIVE AMOUNTS OF GULF
MOISTURE TRAPPED ALONG THE SOUTHEAST TEXAS & LOUISIANA COASTAL
WATERS IN A VERY RICH CONVERGENCE ZONE WHERE LARGE SWATHS OF RAIN
ARE BEING CREATED AND THEN MOVED INLAND.
OBVIOUSLY...THIS IS GOING TO CREATE A VERY GENEROUS AMOUNT OF 1 1/2
TO 2 INCH RAIN AMOUNTS WITH ISOLATED AMOUNTS UP TO THREE INCHES. THE RAIN
WILL BE HERE TO STAY THROUGH THE NIGHT AS OUR HRRR & GFS MODELS
SHOWING OUR NEWLY BORN SURFACE LOW MOVING WEST TO EAST ACROSS OUR
NORTHWEST GULF OF MEXICO THROUGH EARLY MORNING FRIDAY. I RAISED THE
WIND ADVISORY TODAY THROUGH MIDNIGHT FOR I-10 CORRIDOR SOUTH
BECAUSE THIS SURFACE LOW WILL TIGHTEN UP THE WIND FIELD ACROSS OUR
COASTAL AREAS WITH SOME GUSTS AT TIMES FURTHER NORTH AT LEAST
UNTIL MIDNIGHT.
SO...ELEVATED WINDS ARE GOING TO BE A PROBLEM UNTIL MIDNIGHT ALONG
THE COASTAL AREAS AND THE RAINS ARE GOING TO BE THE BIGGEST
PROBLEMS FOR THE ENTIRE AREA OVER THE NEXT 24 HOURS. THE SURFACE
LOW WILL MOVE EAST OF OUR AREA BY NOON FRIDAY...HOWEVER WE WILL
CONTINUE TO EXPECT LIGHT RAIN OR SHOWERS THROUGH THE AFTERNOON
FRIDAY AS THE UPPER LEVEL SYSTEM TRACKS EVEN CLOSER TO US.
RAIN SHOULD EXIT THE ENTIRE AREA BY FRIDAY NIGHT WITH HIGH
PRESSURE BUILDING BACK INTO THE AREA. THE REST OF THE FORECAST
THROUGH DAY SEVEN LOOKS DRY WITH COOL TEMPERATURES THROUGH SUNDAY
MORNING WITH A SLOW WARM-UP FOR THE REST OF NEXT WEEK.
MARINE...
SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT UNTIL 6 PM FRIDAY AS SOUTHEAST
FLOW THIS AFTERNOON TRANSITIONS TO A NORTHERLY FLOW LATER TONIGHT
WITH THE PASSAGE OF A NORTHWEST GULF SURFACE LOW.
06
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 44 48 37 57 39 / 100 30 20 10 0
KBPT 44 49 37 58 40 / 100 30 10 0 0
KAEX 41 45 34 56 36 / 100 40 20 0 0
KLFT 46 48 38 56 39 / 100 30 20 10 0
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE FOLLOWING
ZONES: ACADIA...CALCASIEU...EAST CAMERON...IBERIA...
JEFFERSON DAVIS...LAFAYETTE...LOWER ST. MARTIN...ST. MARY...
UPPER ST. MARTIN...VERMILION...WEST CAMERON.
TX...WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE FOLLOWING
ZONES: JEFFERSON...ORANGE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST FRIDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM CAMERON LA TO HIGH ISLAND TX OUT
20 NM...COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON LA
OUT 20 NM...COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO
INTRACOASTAL CITY LA OUT 20 NM...WATERS FROM INTRACOASTAL
CITY TO CAMERON LA FROM 20 TO 60 NM...WATERS FROM CAMERON
LA TO HIGH ISLAND TX FROM 20 TO 60 NM...WATERS FROM LOWER
ATCHAFALAYA RIVER TO INTRACOASTAL CITY LA FROM 20 TO 60 NM.
SMALL CRAFT EXERCISE CAUTION UNTIL MIDNIGHT CST TONIGHT FOR THE
FOLLOWING ZONES: CALCASIEU LAKE...SABINE LAKE...VERMILION
BAY.
&&
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSLAKECHARLES
WWW.TWITTER.COM/NWSLAKECHARLES
WWW.YOUTUBE.COM/NWSLAKECHARLES
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
225 PM EST WED JAN 21 2015
.SYNOPSIS...
LOW PRESSURE OFF THE NORTH CAROLINA COAST WILL SLOWLY TRACK NORTHEAST
OFF THE VIRGINIA CAPES THIS EVENING. HIGH PRESSURE RETURNS THROUGH
THE END OF THE WORK WEEK. ANOTHER LOW PRESSURE SYSTEM TRACKS NORTHEAST
ALONG THE SOUTHEAST COAST FRIDAY NIGHT...THEN OFF THE MID ATLANTIC
COAST SATURDAY...BRING UNSETTLED CONDITIONS BACK TO THE REGION FOR
SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
CURRENT ANALYSIS SHOWING WEAK SFC LOW CENTERED JUST OFF TO THE E
OF CAPE HATTERAS NC...WITH FRONTAL BNDRY OVER SRN NC. FLOW ALOFT
REMAINS FAIRLY PROGRESSIVE FROM THE WSW. WV SATELLITE REVEALS A MID
LEVEL SHORTWAVE MOVING THROUGH ERN KY AND WV...WITH MODELS
SHIFTING THIS FEATURE ENE THROUGH THE AFTN/EVENING HRS. MEASURABLE PRECIP
THUS FAR THIS MORNING HAS NOT OCCURRED WITHIN THE CWA...VERIFYING
FAIRLY WELL WITH BOTH THE PREVIOUS 06Z RUN AS WELL AS THE CURRENT
RUN (12Z) OF THE NAM. SKIES HAVE CLOUDED UP OVER THE PAST HR ACRS
MOST OF VA AFTER SOME EARLY AM SUNSHINE...AND SOME LIGHT SNOW IS
FINALLY BREAKING OUT OVER FAR NORTHERN VA INTO SOUTHERN PA. FOR
THIS AFTN...FORCING WILL INCREASE OVER THE NORTHERN PORTIONS OF
THE CWA AS THE AFOREMENTIONED SHORTWAVE PUSHES E OF THE MTNS.
SHORTWAVE APPEARS TO BE FAIRLY SHEARED OUT HOWEVER...SO IT IS NOT
EXPECTED TO DROP TO THE SOUTH AND SHOULD NOT AFFECT SOUTHERN VA/NE
NC WITH ANYTHING MORE THAN CLOUDS. HAVE MADE SOME MINOR
ADJUSTMENTS TO POPS...RAMPING THEM UP TO LIKELY OVER THE MD ERN
SHORE AFTER 18Z...TAPERED FAIRLY SHARPLY DOWN TO LOW CHC OVER THE
REMAINING NORTHERN 1/3 OF THE CWA. THROUGH 21Z IS SHOULD BE JUST
SOME LIGHT RAIN WITH SFC TEMPS IN THE UPPER 30S/AROUND 40 F. WITH
SOME LATER AFTN SUNSHINE ANTICIPATED OVER FAR SOUTHERN VA/NE
NC...HIGH TEMPS THERE WILL BE IN THE 50S...WITH HIGHS ONLY AROUND
40 F ACRS THE FAR NORTH.
DURING ROUGHLY THE 21Z-03Z PERIOD...IF THERE IS GOING TO BE ANY
REAL CHC FOR SNOW/SLEET THIS WOULD BE THE MOST FAVORABLE PERIOD...CONFINED
TO THE MD ERN SHORE (TOO WARM AND/OR TOO DRY ELSEWHERE). THIS...AS
BEST FORCING MOVES OVER THIS REGION AS SFC LOW DEEPENS WHILE
TRACKING NE OFF THE SE VA COAST. MODEST CAA KICKS IN NIGHT BEHIND
THE DEPARTING LOW AS WINDS BACK TO THE NORTH AND THEN NORTHWEST.
CLOUD COVER WILL HELP KEEP TEMPS JUST ABOVE FREEZING...BUT THERE
WILL BE THE POTENTIAL FOR A LIGHT ACCUMULATION OF SNOW/SLEET OVER
MAINLY GRASSY SURFACES IN NRN DORCHESTER/WICOMICO COUNTIES AS SFC
WET BULB TEMPS PER THE 12Z NAM AND RAP DROP TO NEAR FREEZING.
ADDED AN HWO MENTION OF THIS FOR THESE AREAS...GRIDDED FORECAST
HAS 0.5" OR LESS OF SNOW/SLEET. OTHERWISE...CLEARING SKIES FROM SW
TO NE LATER THIS EVENING/OVERNIGHT WITH LOWS FROM THE UPPER 20S TO
LOWER 30S MOST AREAS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
QUASI- ZONAL FLOW BEHIND THE SYSTEM WILL BRING CLEARING LATE WED
NIGHT AND THU. OTRW...~1030MB SFC HI PRES BUILDS IN FROM THE MID
MS VALLEY THU-THU NGT. THE RESULT WILL BE MOSTLY SUNNY- PARTLY
CLOUDY THU W/ HI TEMPS MNLY IN THE M/U40S N TO L50S S.
BIG WEATHER MAKER FOR LATE IN THE WEEK ON INTO THE WEEKEND WILL
DEVELOP FROM A SOUTHERN STREAM SHORTWAVE THAT MOVES FROM THE 4
CORNERS REGION THU NGT TO THE GULF COAST FRI. SFC LOW PRESSURE IS
EXPECTED TO DEVELOP ALONG THE COAST DURING THE DAY ON FRI THEN
TRACK NE ALONG THE ATLANTIC COAST FRI NGT AND SAT. ATTM...P-TYPE
LOOKS AS IF IT WOULD BE PREDOMINATELY RAIN IF NOT ALL RAIN FOR THE
FA. WILL INCLUDE SOME PSBL MIXED SN ACRS THE NNW LATE FRI NGT AT
THE ONSET OF PRECIPITATION.
RAISED POPS ACRS THE FA (TO HI CHC/LIKELY) THROUGHOUT THE FA.
HIGHS FRIDAY ARND 40F ON THE LWR MD ERN SHORE TO L40S I-95
CORRIDOR...AND M/U40S IN SE VA/NE NC. LO TEMPS FRI NIGHT IN THE
M30S N TO L40S SE.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
GIVEN TRACK ON MDLS ATTM...CONCERN BY SAT WILL BE PTNTL DRY SLOT
ARRIVING FM THE SW...RESULTING IN PCPN WINDING DOWN/ENDING BEFORE
ANY AIR COLD ENOUGH FM THE PCPN ENDING AS MIXED SN/RA OR ALL SN
(IN THE AFTN/EVE). WILL HAVE HIGHEST POPS SAT MRNG...TAPERING OFF
FM W TO E IN THE AFTN. HI TEMPS FM ARND 40F NW TO THE L50S IN CSTL
NE NC.
DRY CONDS FOR SUN AS THE AFOREMENTIONED LO PRES SYSTM PUSHES
FARTHER OFFSHORE AND THE NEXT SYSTM APPROACHES FM THE W. GFS AND
ECMWF CONTINUE TO HAVE LITTLE RUN-TO-RUN CONSISTENCY SO WILL KEEP
POPS SUN NIGHT THRU TUE IN THE 20-30% RANGE AT THIS POINT. ALSO A
LOT OF UNCERTAINTY REGARDING PTYPE WITH GFS AND ECMWF HAVING LARGE
DIFFERENCES IN THICKNESSES. AS FOR TEMPS...EXPECT SLIGHTLY BLO
NORMAL READINGS ON AVG...WITH HIGHS SUN MSTLY IN THE MID TO UPR
40S...AND UPR 30S TO MID 40S MON AND TUE.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
INCREASING AND LOWERING CLOUDS CONTINUE OVER THE TAF SITES THIS
AFTN AS A COUPLE OF WEAK LO PRES AREAS MOVE ACRS THE MID ATLC
REGION. MVFR CEILINGS EXPECTED AT ALL SITES WITH IFR VIS AT SBY
DUE TO -RA/-SN. CONDITIONS RETURN TO VFR AT ALL TAF SITES LATE
TNGT...EXCEPT SBY AS THE MAIN LO MOVES AWAY OFF THE SRN NEW
ENGLAND CST.
OUTLOOK...MAINLY VFR CONDITIONS EXPECTED THU INTO FRI AFTN...AS HI
PRES BLDS INTO AND OVR THE REGION. THERE WILL BE A CHC FOR RAIN
LATE FRI THRU SAT WITH PERIODS OF IFR POSSIBLE.
&&
.MARINE...
PER LATEST OBS HAVE RAISED A SCA TODAY FOR SOUTHERN BAY AND
COASTAL WATERS FROM PARRAMORE ISLAND ON SOUTH.
PREV DISCUSSION...
ONE LO PRES AREA WILL MOVE FM SRN OH INTO PA BEFORE DISSIPATING
TODAY INTO TNGT...WHILE A SECOND LO TRACKS ACRS NC THEN NE OFF THE
CST AND OUT TO SEA. THIS WILL RESULT IN NE WINDS 10 TO 20 KT
TODAY...BECMG N THIS EVENG...THEN BECMG NW 5 TO 15 KT LATER TNGT
INTO THU MORNG. WAVES WILL BE 1 TO 3 FT AND SEAS WILL BE 3 TO 4 FT
TODAY. HI PRES WILL BLD INTO AND OVR THE AREA THU INTO FRI AFTN.
INTENSIFYING LO PRES WILL THEN TRACK NORTHEAST ALONG THE SOUTHEAST
AND MID ATLANTIC COAST FRIDAY EVENING INTO SATURDAY MORNING...THEN
CONTINUES NORTHEAST TOWARD THE CANADIAN MARITIMES SATURDAY INTO
SATURDAY NIGHT. SCA CONDITIONS POSSIBLE LATE FRI NGT INTO SAT NGT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST THURSDAY FOR ANZ654-656-
658.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ632-
634.
&&
$$
SYNOPSIS...LKB
NEAR TERM...ALB/LKB
SHORT TERM...ALB/MAM
LONG TERM...ALB/MAS
AVIATION...TMG/DAP
MARINE...TMG
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
104 PM EST WED JAN 21 2015
.SYNOPSIS...
LOW PRESSURE WILL AFFECT THE MID-ATLANTIC TODAY. HIGH PRESSURE
RETURNS THURSDAY AND FRIDAY. AREAS OF LOW PRESSURE MAY IMPACT THE
REGION SATURDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE INCLUDED PRINCE WILLIAM...MANASSAS AND MANASSAS PARK IN THE
WINTER WEATHER ADVISORY AS TOTALS THERE ARE NOW EXPECTED TO BE IN
THE 1 TO 2 INCH RANGE AND SNOW WILL BE ONGOING AT THE START OF
THE AFTERNOON RUSH HOUR. HAVE INCREASED SOME TOTALS AS
WELL...PARTICULARLY FOR NORTH CENTRAL MARYLAND/BALTIMORE AREA
WHERE BANDING WILL OCCUR THROUGH THE NEXT FEW HOURS AND LEAD TO 2
TO 4 INCHES OF ACCUMULATION.
PREV...
SNOW HAS OVERSPREAD MUCH OF WESTERN MD/EASTERN WV PANHANDLE AND
NORTHERN SHENANDOAH VALLEY SO FAR THIS MORNING. SNOW WILL CONTINUE
SPREADING EASTWARD INTO DC-BALTIMORE METRO AREAS OVER THE NEXT
COUPLE OF HOURS PER RADAR TRENDS AND LATEST HRRR RUNS. HIGHEST
TOTALS STILL LOOK TO BE NEAR THE MASON DIXON LINE... 2 TO 4 INCHES
/WITH BANDING POTENTIAL/ TAPERING OFF TO AROUND 1 INCH TOWARD I-66.
SOUTH OF HERE...LOWER QPF AND SNOW MIXING WITH OR CHANGING TO RAIN
WILL CUT DOWN ON ACCUMULATIONS. WINTER WEATHER ADVISORY REMAINS AS
IS FOR NOW...CONTINUING UNTIL 6 PM. AFTERNOON RUSH HOUR WILL BE
IMPACTED IN THE ADVISORY AREA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
WINTER WEATHER ADVISORY ENDS AT 6 PM. THERE MAY BE SOME LINGERING
PRECIPITATION AN HOUR OR TWO BEYOND THIS IN PARTS OF MARYLAND NEAR
THE BAY PER LATEST MODEL TRENDS...BUT LOW PRESSURE SHOULD EXIT THE
AREA BY EARLY WEDNESDAY EVENING AND PROMOTE AN END TO PRECIPITATION.
WILL HAVE TO WATCH FOR A POTENTIAL RE-FREEZE. PATCHY DRIZZLE OR
FREEZING DRIZZLE IS POSSIBLE WEDNESDAY EVENING DUE TO SATURATED LOW
LEVELS AND COOLER AIR TRAPPED ABOVE THE SURFACE. THEREFORE...WET OR
SLUSHY ROADS MAY RE- FREEZE AS TEMPERATURES DROP BELOW FREEZING.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
"FAST FLOW IN A WRN RDG/ERN TROF" SORT OF SUMS UP A DECENT PART OF
THE XTND FCST. THE FIRST PART OF THE FCST IS RLVTLY PLACID AS HIGH
PRES SETTLES OVR THE AREA. HIGHS IN THE LM40S...LOWS IN THE M20S
XCPT WARMER IN THE CITIES.
WHILE NOTHING LOOKS AS AMPLIFIED AS IT DID LAST JAN THE MDLS ARE
STILL PROJECTING A RDG OVR THE WRN U.S. W/ RLVTLY FAST MOVG LOW
PRES AREAS COMING OUT OF AN ACTIVE SRN STRM. THE FIRST OF THESE
LOOKS TO IMPACT THE AREA FRI NGT/SAT. THERE ISN`T A LOT OF COLD
AIR ACROSS THE ERN U.S. BUT IF THE LOW TAKES A TRACK FM GA TO ORF
THAT WL KEEP THE CWA ON THE COLDER SIDE OF THINGS. ATTM BOTH GFS
AND EURO ARE KEEPING THE 850-1000MB TCKNS BTWN 1296-1300M...JUST
COLD ENOUGH TO HV CONCERNS THE PCPN COULD FALL AS WET SNOW. WE`LL
TRY TO FINE TUNE THE DETAILS IN THE DAYS TO COME.
AND IN THE FAST FLOW IT APPEARS THAT ANOTHER LOW PRES AREA WL DIVE
DOWN FM THE WRN RDG...OVR MN/WI SUN AND INTO THE MID ATLC SUN
NGT/MON. AGN THE TRACK LOOKS TO KEEP THE LOW S OF THE CWA...AND AGN
TEMP COLUMN LOOKS TO BE MARGINALLY COLD ENOUGH FOR CONCERNS OF
SNOW. MORE TO COME.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
SNOW WILL OVERSPREAD THE TERMINALS LATE THIS MORNING...POSSIBLY
MIXING WITH RAIN AT CHO/DCA/IAD LATE AFTERNOON. IFR CONDITIONS ARE
EXPECTED. PRECIPITATION WILL MOVE OFF TO THE NORTHEAST LATER IN
THE AFTERNOON BUT IFR CONDITIONS MAY CONTINUE THROUGH TONIGHT AS
LOW- LEVEL MOISTURE REMAINS TRAPPED UNDERNEATH THE SUBSIDENCE
INVERSION.
HIGH PRESSURE BUILDS INTO THE AREA FOR THURSDAY/FRIDAY. LOW PRESSURE
MAY BRING PRECIP/FLIGHT RESTRICTIONS SATURDAY.
&&
.MARINE...
A COASTAL LOW WILL DEVELOP TODAY. SOME CHANNELING WILL DEVELOP WITH
GUSTS INTO THE TEENS...BUT NOT EXPECTING GUSTS TO SCA CRITERIA.
WINDS XPCTD TO BE BLO SCA VALUES THU/FRI AS HIGH PRES BUILDS INTO
THE AREA. AN AREA OF LOW PRES MAY IMPACT THE WATERS SAT...BRINGING
WINTRY PCPN.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR DCZ001.
MD...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR
MDZ003>006-011-013-014-501>508.
VA...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR VAZ028-
031-052>054-503>506.
WV...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR
WVZ050>053-055-501>506.
MARINE...NONE.
&&
$$
SYNOPSIS...KS/ABW
NEAR TERM...BPP/KS
SHORT TERM...ABW
LONG TERM...ABW
AVIATION...BPP/KS/ABW
MARINE...BPP/KS/ABW
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1045 AM EST WED JAN 21 2015
.SYNOPSIS...
LOW PRESSURE OFF THE NORTH CAROLINA COAST WILL SLOWLY TRACK NORTHEAST
OFF THE VIRGINIA CAPES THIS EVENING. HIGH PRESSURE RETURNS THROUGH
THE END OF THE WORK WEEK. ANOTHER LOW PRESSURE SYSTEM TRACKS NORTHEAST
ALONG THE SOUTHEAST COAST FRIDAY NIGHT...THEN OFF THE MID ATLANTIC
COAST SATURDAY...BRING UNSETTLED CONDITIONS BACK TO THE REGION FOR
SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
CURRENT ANALYSIS SHOWING WEAK SFC LOW CENTERED JUST OFF TO THE E
OF CAPE HATTERAS NC...WITH FRONTAL BNDRY OVER SRN NC. FLOW ALOFT
REMAINS FAIRLY PROGRESSIVE FROM THE WSW. WV SATELLITE REVEALS A MID
LEVEL SHORTWAVE MOVING THROUGH ERN KY AND WV...WITH MODELS
SHIFTING THIS FEATURE ENE THROUGH THE AFTN/EVENING HRS. MEASURABLE PRECIP
THUS FAR THIS MORNING HAS NOT OCCURRED WITHIN THE CWA...VERIFYING
FAIRLY WELL WITH BOTH THE PREVIOUS 06Z RUN AS WELL AS THE CURRENT
RUN (12Z) OF THE NAM. SKIES HAVE CLOUDED UP OVER THE PAST HR ACRS
MOST OF VA AFTER SOME EARLY AM SUNSHINE...AND SOME LIGHT SNOW IS
FINALLY BREAKING OUT OVER FAR NORTHERN VA INTO SOUTHERN PA. FOR
THIS AFTN...FORCING WILL INCREASE OVER THE NORTHERN PORTIONS OF
THE CWA AS THE AFOREMENTIONED SHORTWAVE PUSHES E OF THE MTNS.
SHORTWAVE APPEARS TO BE FAIRLY SHEARED OUT HOWEVER...SO IT IS NOT
EXPECTED TO DROP TO THE SOUTH AND SHOULD NOT AFFECT SOUTHERN VA/NE
NC WITH ANYTHING MORE THAN CLOUDS. HAVE MADE SOME MINOR
ADJUSTMENTS TO POPS...RAMPING THEM UP TO LIKELY OVER THE MD ERN
SHORE AFTER 18Z...TAPERED FAIRLY SHARPLY DOWN TO LOW CHC OVER THE
REMAINING NORTHERN 1/3 OF THE CWA. THROUGH 21Z IS SHOULD BE JUST
SOME LIGHT RAIN WITH SFC TEMPS IN THE UPPER 30S/AROUND 40 F. WITH
SOME LATER AFTN SUNSHINE ANTICIPATED OVER FAR SOUTHERN VA/NE
NC...HIGH TEMPS THERE WILL BE IN THE 50S...WITH HIGHS ONLY AROUND
40 F ACRS THE FAR NORTH.
DURING ROUGHLY THE 21Z-03Z PERIOD...IF THERE IS GOING TO BE ANY
REAL CHC FOR SNOW/SLEET THIS WOULD BE THE MOST FAVORABLE PERIOD...CONFINED
TO THE MD ERN SHORE (TOO WARM AND/OR TOO DRY ELSEWHERE). THIS...AS
BEST FORCING MOVES OVER THIS REGION AS SFC LOW DEEPENS WHILE
TRACKING NE OFF THE SE VA COAST. MODEST CAA KICKS IN NIGHT BEHIND
THE DEPARTING LOW AS WINDS BACK TO THE NORTH AND THEN NORTHWEST.
CLOUD COVER WILL HELP KEEP TEMPS JUST ABOVE FREEZING...BUT THERE
WILL BE THE POTENTIAL FOR A LIGHT ACCUMULATION OF SNOW/SLEET OVER
MAINLY GRASSY SURFACES IN NRN DORCHESTER/WICOMICO COUNTIES AS SFC
WET BULB TEMPS PER THE 12Z NAM AND RAP DROP TO NEAR FREEZING.
ADDED AN HWO MENTION OF THIS FOR THESE AREAS...GRIDDED FORECAST
HAS 0.5" OR LESS OF SNOW/SLEET. OTHERWISE...CLEARING SKIES FROM SW
TO NE LATER THIS EVENING/OVERNIGHT WITH LOWS FROM THE UPPER 20S TO
LOWER 30S MOST AREAS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
QUASI- ZONAL FLOW BEHIND THE SYSTEM WILL BRING CLEARING LATE WED
NIGHT AND THU. OTRW...~1030MB SFC HI PRES BUILDS IN FROM THE MID
MS VALLEY THU-THU NGT. THE RESULT WILL BE MOSTLY SUNNY- PARTLY
CLOUDY THU W/ HI TEMPS MNLY IN THE M/U40S N TO L50S S.
BIG WEATHER MAKER FOR LATE IN THE WEEK ON INTO THE WEEKEND WILL
DEVELOP FROM A SOUTHERN STREAM SHORTWAVE THAT MOVES FROM THE 4
CORNERS REGION THU NGT TO THE GULF COAST FRI. SFC LOW PRESSURE IS
EXPECTED TO DEVELOP ALONG THE COAST DURING THE DAY ON FRI THEN
TRACK NE ALONG THE ATLANTIC COAST FRI NGT AND SAT. ATTM...P-TYPE
LOOKS AS IF IT WOULD BE PREDOMINATELY RAIN IF NOT ALL RAIN FOR THE
FA. WILL INCLUDE SOME PSBL MIXED SN ACRS THE NNW LATE FRI NGT AT
THE ONSET OF PRECIPITATION.
RAISED POPS ACRS THE FA (TO HI CHC/LIKELY) THROUGHOUT THE FA.
HIGHS FRIDAY ARND 40F ON THE LWR MD ERN SHORE TO L40S I-95
CORRIDOR...AND M/U40S IN SE VA/NE NC. LO TEMPS FRI NIGHT IN THE
M30S N TO L40S SE.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
GIVEN TRACK ON MDLS ATTM...CONCERN BY SAT WILL BE PTNTL DRY SLOT
ARRIVING FM THE SW...RESULTING IN PCPN WINDING DOWN/ENDING BEFORE
ANY AIR COLD ENOUGH FM THE PCPN ENDING AS MIXED SN/RA OR ALL SN
(IN THE AFTN/EVE). WILL HAVE HIGHEST POPS SAT MRNG...TAPERING OFF
FM W TO E IN THE AFTN. HI TEMPS FM ARND 40F NW TO THE L50S IN CSTL
NE NC.
DRY CONDS FOR SUN AS THE AFOREMENTIONED LO PRES SYSTM PUSHES
FARTHER OFFSHORE AND THE NEXT SYSTM APPROACHES FM THE W. GFS AND
ECMWF CONTINUE TO HAVE LITTLE RUN-TO-RUN CONSISTENCY SO WILL KEEP
POPS SUN NIGHT THRU TUE IN THE 20-30% RANGE AT THIS POINT. ALSO A
LOT OF UNCERTAINTY REGARDING PTYPE WITH GFS AND ECMWF HAVING LARGE
DIFFERENCES IN THICKNESSES. AS FOR TEMPS...EXPECT SLIGHTLY BLO
NORMAL READINGS ON AVG...WITH HIGHS SUN MSTLY IN THE MID TO UPR
40S...AND UPR 30S TO MID 40S MON AND TUE.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
INCREASING AND LOWERING CLOUDS EXPECTED OVER THE TAF SITES DURING
TODAY...AS A COUPLE OF WEAK LO PRES AREAS MOVE ACRS THE MID ATLC
REGION. WENT CLOSER TO THE NAM FCST (GUIDANCE) AND ONLY MENTIONING
-RA IN THE SBY TAF AT THIS TIME. BUT...DO HAVE CIGS LOWERING TO
IFR AT ALL TAF SITES EXCEPT RIC DURING THIS AFTN. CONDITIONS
SHOULD RETURN TO VFR AT ALL TAF SITES LATE TNGT...EXCEPT MAYBE SBY
AS THE MAIN LO MOVES AWAY OFF THE SRN NEW ENGLAND CST.
OUTLOOK...MAINLY VFR CONDITIONS EXPECTED THU INTO FRI AFTN...AS HI
PRES BLDS INTO AND OVR THE REGION. THERE WILL BE A CHC FOR RAIN
LATE FRI THRU SAT WITH PERIODS OF IFR POSSIBLE.
&&
.MARINE...
PER LATEST OBS HAVE RAISED A SCA TODAY FOR SOUTHERN BAY AND
COASTAL WATERS FROM PARRAMORE ISLAND ON SOUTH.
PREV DISCUSSION...
ONE LO PRES AREA WILL MOVE FM SRN OH INTO PA BEFORE DISSIPATING
TODAY INTO TNGT...WHILE A SECOND LO TRACKS ACRS NC THEN NE OFF THE
CST AND OUT TO SEA. THIS WILL RESULT IN NE WINDS 10 TO 20 KT
TODAY...BECMG N THIS EVENG...THEN BECMG NW 5 TO 15 KT LATER TNGT
INTO THU MORNG. WAVES WILL BE 1 TO 3 FT AND SEAS WILL BE 3 TO 4 FT
TODAY. HI PRES WILL BLD INTO AND OVR THE AREA THU INTO FRI AFTN.
INTENSIFYING LO PRES WILL THEN TRACK NORTHEAST ALONG THE SOUTHEAST
AND MID ATLANTIC COAST FRIDAY EVENING INTO SATURDAY MORNING...THEN
CONTINUES NORTHEAST TOWARD THE CANADIAN MARITIMES SATURDAY INTO
SATURDAY NIGHT. SCA CONDITIONS POSSIBLE LATE FRI NGT INTO SAT NGT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EST THURSDAY FOR ANZ654-656-
658.
SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR ANZ632-
634.
&&
$$
SYNOPSIS...LKB
NEAR TERM...ALB/LKB
SHORT TERM...ALB/MAM
LONG TERM...ALB/MAS
AVIATION...TMG
MARINE...TMG
AREA FORECAST DISCUSSION...CORRECTED
NWS BALTIMORE MD/WASHINGTON DC
1032 AM EST WED JAN 21 2015
.SYNOPSIS...
LOW PRESSURE WILL AFFECT THE MID-ATLANTIC TODAY. HIGH PRESSURE
RETURNS THURSDAY AND FRIDAY. AREAS OF LOW PRESSURE MAY IMPACT THE
REGION SATURDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SNOW HAS OVERSPREAD MUCH OF WESTERN MD/EASTERN WV PANHANDLE AND
NORTHERN SHENANDOAH VALLEY SO FAR THIS MORNING. SNOW WILL CONTINUE
SPREADING EASTWARD INTO DC-BALTIMORE METRO AREAS OVER THE NEXT
COUPLE OF HOURS PER RADAR TRENDS AND LATEST HRRR RUNS. HIGHEST
TOTALS STILL LOOK TO BE NEAR THE MASON DIXON LINE... 2 TO 4 INCHES
/WITH BANDING POTENTIAL/ TAPERING OFF TO AROUND 1 INCH TOWARD I-66.
SOUTH OF HERE...LOWER QPF AND SNOW MIXING WITH OR CHANGING TO RAIN
WILL CUT DOWN ON ACCUMULATIONS. WINTER WEATHER ADVISORY REMAINS AS
IS FOR NOW...CONTINUING UNTIL 6 PM. AFTERNOON RUSH HOUR WILL BE
IMPACTED IN THE ADVISORY AREA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
WINTER WEATHER ADVISORY ENDS AT 6 PM. THERE MAY BE SOME LINGERING
PRECIPITATION AN HOUR OR TWO BEYOND THIS IN PARTS OF MARYLAND NEAR
THE BAY PER LATEST MODEL TRENDS...BUT LOW PRESSURE SHOULD EXIT THE
AREA BY EARLY WEDNESDAY EVENING AND PROMOTE AN END TO PRECIPITATION.
WILL HAVE TO WATCH FOR A POTENTIAL RE-FREEZE. PATCHY DRIZZLE OR
FREEZING DRIZZLE IS POSSIBLE WEDNESDAY EVENING DUE TO SATURATED LOW
LEVELS AND COOLER AIR TRAPPED ABOVE THE SURFACE. THEREFORE...WET OR
SLUSHY ROADS MAY RE- FREEZE AS TEMPERATURES DROP BELOW FREEZING.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
"FAST FLOW IN A WRN RDG/ERN TROF" SORT OF SUMS UP A DECENT PART OF
THE XTND FCST. THE FIRST PART OF THE FCST IS RLVTLY PLACID AS HIGH
PRES SETTLES OVR THE AREA. HIGHS IN THE LM40S...LOWS IN THE M20S
XCPT WARMER IN THE CITIES.
WHILE NOTHING LOOKS AS AMPLIFIED AS IT DID LAST JAN THE MDLS ARE
STILL PROJECTING A RDG OVR THE WRN U.S. W/ RLVTLY FAST MOVG LOW
PRES AREAS COMING OUT OF AN ACTIVE SRN STRM. THE FIRST OF THESE
LOOKS TO IMPACT THE AREA FRI NGT/SAT. THERE ISN`T A LOT OF COLD
AIR ACROSS THE ERN U.S. BUT IF THE LOW TAKES A TRACK FM GA TO ORF
THAT WL KEEP THE CWA ON THE COLDER SIDE OF THINGS. ATTM BOTH GFS
AND EURO ARE KEEPING THE 850-1000MB TCKNS BTWN 1296-1300M...JUST
COLD ENOUGH TO HV CONCERNS THE PCPN COULD FALL AS WET SNOW. WE`LL
TRY TO FINE TUNE THE DETAILS IN THE DAYS TO COME.
AND IN THE FAST FLOW IT APPEARS THAT ANOTHER LOW PRES AREA WL DIVE
DOWN FM THE WRN RDG...OVR MN/WI SUN AND INTO THE MID ATLC SUN
NGT/MON. AGN THE TRACK LOOKS TO KEEP THE LOW S OF THE CWA...AND AGN
TEMP COLUMN LOOKS TO BE MARGINALLY COLD ENOUGH FOR CONCERNS OF
SNOW. MORE TO COME.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
SNOW WILL OVERSPREAD THE TERMINALS LATE THIS MORNING...POSSIBLY
MIXING WITH RAIN AT CHO/DCA/IAD LATE AFTERNOON. IFR CONDITIONS ARE
EXPECTED. PRECIPITATION WILL MOVE OFF TO THE NORTHEAST LATER IN
THE AFTERNOON BUT IFR CONDITIONS MAY CONTINUE THROUGH TONIGHT AS
LOW- LEVEL MOISTURE REMAINS TRAPPED UNDERNEATH THE SUBSIDENCE
INVERSION.
HIGH PRESSURE BUILDS INTO THE AREA FOR THURSDAY/FRIDAY. LOW PRESSURE
MAY BRING PRECIP/FLIGHT RESTRICTIONS SATURDAY.
&&
.MARINE...
A COASTAL LOW WILL DEVELOP TODAY. SOME CHANNELING WILL DEVELOP WITH
GUSTS INTO THE TEENS...BUT NOT EXPECTING GUSTS TO SCA CRITERIA.
WINDS XPCTD TO BE BLO SCA VALUES THU/FRI AS HIGH PRES BUILDS INTO
THE AREA. AN AREA OF LOW PRES MAY IMPACT THE WATERS SAT...BRINGING
WINTRY PCPN.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR DCZ001.
MD...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR
MDZ003>006-011-013-014-501>508.
VA...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR VAZ028-
031-053-054-503>506.
WV...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR
WVZ050>053-055-501>506.
MARINE...NONE.
&&
$$
SYNOPSIS...KS/ABW
NEAR TERM...BPP/KS
SHORT TERM...ABW
LONG TERM...ABW
AVIATION...BPP/KS/ABW
MARINE...BPP/KS/ABW
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1031 AM EST WED JAN 21 2015
.SYNOPSIS...
LOW PRESSURE OFF THE NORTH CAROLINA COAST WILL SLOWLY TRACK NORTHEAST
OFF THE VIRGINIA CAPES THIS EVENING. HIGH PRESSURE RETURNS THROUGH
THE END OF THE WORK WEEK. ANOTHER LOW PRESSURE SYSTEM TRACKS NORTHEAST
ALONG THE SOUTHEAST COAST FRIDAY NIGHT...THEN OFF THE MID ATLANTIC
COAST SATURDAY...BRING UNSETTLED CONDITIONS BACK TO THE REGION FOR
SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
CURRENT ANALYSIS SHOWING WEAK SFC LOW CENTERED JUST OFF TO THE E
OF CAPE HATTERAS NC...WITH FRONTAL BNDRY OVER SRN NC. FLOW ALOFT
REMAINS FAIRLY PROGRESSIVE FROM THE WSW. WV SATELLITE REVEALS A MID
LEVEL SHORTWAVE MOVING THROUGH ERN KY AND WV...WITH MODELS
SHIFTING THIS FEATURE ENE THROUGH THE AFTN/EVENING HRS. MEASURABLE PRECIP
THUS FAR THIS MORNING HAS NOT OCCURRED WITHIN THE CWA...VERIFYING
FAIRLY WELL WITH BOTH THE PREVIOUS 06Z RUN AS WELL AS THE CURRENT
RUN (12Z) OF THE NAM. SKIES HAVE CLOUDED UP OVER THE PAST HR ACRS
MOST OF VA AFTER SOME EARLY AM SUNSHINE...AND SOME LIGHT SNOW IS
FINALLY BREAKING OUT OVER FAR NORTHERN VA INTO SOUTHERN PA. FOR
THIS AFTN...FORCING WILL INCREASE OVER THE NORTHERN PORTIONS OF
THE CWA AS THE AFOREMENTIONED SHORTWAVE PUSHES E OF THE MTNS.
SHORTWAVE APPEARS TO BE FAIRLY SHEARED OUT HOWEVER...SO IT IS NOT
EXPECTED TO DROP TO THE SOUTH AND SHOULD NOT AFFECT SOUTHERN VA/NE
NC WITH ANYTHING MORE THAN CLOUDS. HAVE MADE SOME MINOR
ADJUSTMENTS TO POPS...RAMPING THEM UP TO LIKELY OVER THE MD ERN
SHORE AFTER 18Z...TAPERED FAIRLY SHARPLY DOWN TO LOW CHC OVER THE
REMAINING NORTHERN 1/3 OF THE CWA. THROUGH 21Z IS SHOULD BE JUST
SOME LIGHT RAIN WITH SFC TEMPS IN THE UPPER 30S/AROUND 40 F. WITH
SOME LATER AFTN SUNSHINE ANTICIPATED OVER FAR SOUTHERN VA/NE
NC...HIGH TEMPS THERE WILL BE IN THE 50S...WITH HIGHS ONLY AROUND
40 F ACRS THE FAR NORTH.
DURING ROUGHLY THE 21Z-03Z PERIOD...IF THERE IS GOING TO BE ANY
REAL CHC FOR SNOW/SLEET THIS WOULD BE THE MOST FAVORABLE PERIOD...CONFINED
TO THE MD ERN SHORE (TOO WARM AND/OR TOO DRY ELSEWHERE). THIS...AS
BEST FORCING MOVES OVER THIS REGION AS SFC LOW DEEPENS WHILE
TRACKING NE OFF THE SE VA COAST. MODEST CAA KICKS IN NIGHT BEHIND
THE DEPARTING LOW AS WINDS BACK TO THE NORTH AND THEN NORTHWEST.
CLOUD COVER WILL HELP KEEP TEMPS JUST ABOVE FREEZING...BUT THERE
WILL BE THE POTENTIAL FOR A LIGHT ACCUMULATION OF SNOW/SLEET OVER
MAINLY GRASSY SURFACES IN NRN DORCHESTER/WICOMICO COUNTIES AS SFC
WET BULB TEMPS PER THE 12Z NAM AND RAP DROP TO NEAR FREEZING.
ADDED AN HWO MENTION OF THIS FOR THESE AREAS...GRIDDED FORECAST
HAS 0.5" OR LESS OF SNOW/SLEET. OTHERWISE...CLEARING SKIES FROM SW
TO NE LATER THIS EVENING/OVERNIGHT WITH LOWS FROM THE UPPER 20S TO
LOWER 30S MOST AREAS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
QUASI- ZONAL FLOW BEHIND THE SYSTEM WILL BRING CLEARING LATE WED
NIGHT AND THU. OTRW...~1030MB SFC HI PRES BUILDS IN FROM THE MID
MS VALLEY THU-THU NGT. THE RESULT WILL BE MOSTLY SUNNY- PARTLY
CLOUDY THU W/ HI TEMPS MNLY IN THE M/U40S N TO L50S S.
BIG WEATHER MAKER FOR LATE IN THE WEEK ON INTO THE WEEKEND WILL
DEVELOP FROM A SOUTHERN STREAM SHORTWAVE THAT MOVES FROM THE 4
CORNERS REGION THU NGT TO THE GULF COAST FRI. SFC LOW PRESSURE IS
EXPECTED TO DEVELOP ALONG THE COAST DURING THE DAY ON FRI THEN
TRACK NE ALONG THE ATLANTIC COAST FRI NGT AND SAT. ATTM...P-TYPE
LOOKS AS IF IT WOULD BE PREDOMINATELY RAIN IF NOT ALL RAIN FOR THE
FA. WILL INCLUDE SOME PSBL MIXED SN ACRS THE NNW LATE FRI NGT AT
THE ONSET OF PRECIPITATION.
RAISED POPS ACRS THE FA (TO HI CHC/LIKELY) THROUGHOUT THE FA.
HIGHS FRIDAY ARND 40F ON THE LWR MD ERN SHORE TO L40S I-95
CORRIDOR...AND M/U40S IN SE VA/NE NC. LO TEMPS FRI NIGHT IN THE
M30S N TO L40S SE.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
GIVEN TRACK ON MDLS ATTM...CONCERN BY SAT WILL BE PTNTL DRY SLOT
ARRIVING FM THE SW...RESULTING IN PCPN WINDING DOWN/ENDING BEFORE
ANY AIR COLD ENOUGH FM THE PCPN ENDING AS MIXED SN/RA OR ALL SN
(IN THE AFTN/EVE). WILL HAVE HIGHEST POPS SAT MRNG...TAPERING OFF
FM W TO E IN THE AFTN. HI TEMPS FM ARND 40F NW TO THE L50S IN CSTL
NE NC.
DRY CONDS FOR SUN AS THE AFOREMENTIONED LO PRES SYSTM PUSHES
FARTHER OFFSHORE AND THE NEXT SYSTM APPROACHES FM THE W. GFS AND
ECMWF CONTINUE TO HAVE LITTLE RUN-TO-RUN CONSISTENCY SO WILL KEEP
POPS SUN NIGHT THRU TUE IN THE 20-30% RANGE AT THIS POINT. ALSO A
LOT OF UNCERTAINTY REGARDING PTYPE WITH GFS AND ECMWF HAVING LARGE
DIFFERENCES IN THICKNESSES. AS FOR TEMPS...EXPECT SLIGHTLY BLO
NORMAL READINGS ON AVG...WITH HIGHS SUN MSTLY IN THE MID TO UPR
40S...AND UPR 30S TO MID 40S MON AND TUE.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
INCREASING AND LOWERING CLOUDS EXPECTED OVER THE TAF SITES DURING
TODAY...AS A COUPLE OF WEAK LO PRES AREAS MOVE ACRS THE MID ATLC
REGION. WENT CLOSER TO THE NAM FCST (GUIDANCE) AND ONLY MENTIONING
-RA IN THE SBY TAF AT THIS TIME. BUT...DO HAVE CIGS LOWERING TO
IFR AT ALL TAF SITES EXCEPT RIC DURING THIS AFTN. CONDITIONS
SHOULD RETURN TO VFR AT ALL TAF SITES LATE TNGT...EXCEPT MAYBE SBY
AS THE MAIN LO MOVES AWAY OFF THE SRN NEW ENGLAND CST.
OUTLOOK...MAINLY VFR CONDITIONS EXPECTED THU INTO FRI AFTN...AS HI
PRES BLDS INTO AND OVR THE REGION. THERE WILL BE A CHC FOR RAIN
LATE FRI THRU SAT WITH PERIODS OF IFR POSSIBLE.
&&
.MARINE...
PER LATEST OBS HAVE RAISED A SCA TODAY FOR SOUTHERN BAY AND
COASTAL WATERS FROM CAPE CHARLES ON SOUTH.
PREV DISCUSSION...
NO HEADLINES IN THE SHORT TERM TODAY THRU THU NGT. ONE LO PRES
AREA WILL MOVE FM SRN OH INTO PA BEFORE DISSIPATING TODAY INTO
TNGT...WHILE A SECOND LO TRACKS ACRS NC THEN NE OFF THE CST AND
OUT TO SEA. THIS WILL RESULT IN NE WINDS 10 TO 20 KT TODAY...BECMG
N THIS EVENG...THEN BECMG NW 5 TO 15 KT LATER TNGT INTO THU MORNG.
WAVES WILL BE 1 TO 3 FT AND SEAS WILL BE 3 TO 4 FT TODAY. HI PRES
WILL BLD INTO AND OVR THE AREA THU INTO FRI AFTN. INTENSIFYING LO
PRES WILL THEN TRACK NORTHEAST ALONG THE SOUTHEAST AND MID
ATLANTIC COAST FRIDAY EVENING INTO SATURDAY MORNING...THEN
CONTINUES NORTHEAST TOWARD THE CANADIAN MARITIMES SATURDAY INTO
SATURDAY NIGHT. SCA CONDITIONS POSSIBLE LATE FRI NGT INTO SAT NGT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LKB
NEAR TERM...LKB
SHORT TERM...ALB/MAM
LONG TERM...ALB/MAS
AVIATION...TMG
MARINE...TMG/DAP/BMD
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1030 AM EST WED JAN 21 2015
.SYNOPSIS...
LOW PRESSURE WILL AFFECT THE MID-ATLANTIC TODAY. HIGH PRESSURE
RETURNS THURSDAY AND FRIDAY. AREAS OF LOW PRESSURE MAY IMPACT THE
REGION SATURDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SNOW HAS OVERSPREAD MUCH OF WESTERN MD/EASTERN WV PANHANDLE AND
NORTHERN SHENANDOAH VALLEY SO THIS MORNING. SNOW WILL CONTINUE
SPREADING EASTWARD INTO DC-BALTIMORE METRO AREAS OVER THE NEXT
COUPLE OF HOURS PER RADAR TRENDS AND LATEST HRRR RUNS. HIGHEST
TOTALS STILL LOOK TO BE NEAR THE MASON DIXON LINE... 2 TO 4
INCHES /WITH BANDING POTENTIAL/ TAPERING OFF TO AROUND 1 INCH
TOWARD I-66. SOUTH OF HERE...LOWER QPF AND SNOW MIXING WITH OR
CHANGING TO RAIN WILL CUT DOWN ON ACCUMULATIONS. WINTER WEATHER
ADVISORY REMAINS AS IS FOR NOW...CONTINUING UNTIL 6 PM. AFTERNOON
RUSH HOUR WILL BE IMPACTED IN THE ADVISORY AREA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
WINTER WEATHER ADVISORY ENDS AT 6 PM. THERE MAY BE SOME LINGERING
PRECIPITATION AN HOUR OR TWO BEYOND THIS IN PARTS OF MARYLAND NEAR
THE BAY PER LATEST MODEL TRENDS...BUT LOW PRESSURE SHOULD EXIT THE
AREA BY EARLY WEDNESDAY EVENING AND PROMOTE AN END TO PRECIPITATION.
WILL HAVE TO WATCH FOR A POTENTIAL RE-FREEZE. PATCHY DRIZZLE OR
FREEZING DRIZZLE IS POSSIBLE WEDNESDAY EVENING DUE TO SATURATED LOW
LEVELS AND COOLER AIR TRAPPED ABOVE THE SURFACE. THEREFORE...WET OR
SLUSHY ROADS MAY RE- FREEZE AS TEMPERATURES DROP BELOW FREEZING.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
"FAST FLOW IN A WRN RDG/ERN TROF" SORT OF SUMS UP A DECENT PART OF
THE XTND FCST. THE FIRST PART OF THE FCST IS RLVTLY PLACID AS HIGH
PRES SETTLES OVR THE AREA. HIGHS IN THE LM40S...LOWS IN THE M20S
XCPT WARMER IN THE CITIES.
WHILE NOTHING LOOKS AS AMPLIFIED AS IT DID LAST JAN THE MDLS ARE
STILL PROJECTING A RDG OVR THE WRN U.S. W/ RLVTLY FAST MOVG LOW
PRES AREAS COMING OUT OF AN ACTIVE SRN STRM. THE FIRST OF THESE
LOOKS TO IMPACT THE AREA FRI NGT/SAT. THERE ISN`T A LOT OF COLD
AIR ACROSS THE ERN U.S. BUT IF THE LOW TAKES A TRACK FM GA TO ORF
THAT WL KEEP THE CWA ON THE COLDER SIDE OF THINGS. ATTM BOTH GFS
AND EURO ARE KEEPING THE 850-1000MB TCKNS BTWN 1296-1300M...JUST
COLD ENOUGH TO HV CONCERNS THE PCPN COULD FALL AS WET SNOW. WE`LL
TRY TO FINE TUNE THE DETAILS IN THE DAYS TO COME.
AND IN THE FAST FLOW IT APPEARS THAT ANOTHER LOW PRES AREA WL DIVE
DOWN FM THE WRN RDG...OVR MN/WI SUN AND INTO THE MID ATLC SUN
NGT/MON. AGN THE TRACK LOOKS TO KEEP THE LOW S OF THE CWA...AND AGN
TEMP COLUMN LOOKS TO BE MARGINALLY COLD ENOUGH FOR CONCERNS OF
SNOW. MORE TO COME.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
SNOW WILL OVERSPREAD THE TERMINALS LATE THIS MORNING...POSSIBLY
MIXING WITH RAIN AT CHO/DCA/IAD LATE AFTERNOON. IFR CONDITIONS ARE
EXPECTED. PRECIPITATION WILL MOVE OFF TO THE NORTHEAST LATER IN
THE AFTERNOON BUT IFR CONDITIONS MAY CONTINUE THROUGH TONIGHT AS
LOW- LEVEL MOISTURE REMAINS TRAPPED UNDERNEATH THE SUBSIDENCE
INVERSION.
HIGH PRESSURE BUILDS INTO THE AREA FOR THURSDAY/FRIDAY. LOW PRESSURE
MAY BRING PRECIP/FLIGHT RESTRICTIONS SATURDAY.
&&
.MARINE...
A COASTAL LOW WILL DEVELOP TODAY. SOME CHANNELING WILL DEVELOP WITH
GUSTS INTO THE TEENS...BUT NOT EXPECTING GUSTS TO SCA CRITERIA.
WINDS XPCTD TO BE BLO SCA VALUES THU/FRI AS HIGH PRES BUILDS INTO
THE AREA. AN AREA OF LOW PRES MAY IMPACT THE WATERS SAT...BRINGING
WINTRY PCPN.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR DCZ001.
MD...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR
MDZ003>006-011-013-014-501>508.
VA...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR VAZ028-
031-053-054-503>506.
WV...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR
WVZ050>053-055-501>506.
MARINE...NONE.
&&
$$
SYNOPSIS...KS/ABW
NEAR TERM...BPP/KS
SHORT TERM...ABW
LONG TERM...ABW
AVIATION...BPP/KS/ABW
MARINE...BPP/KS/ABW
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
358 AM EST WED JAN 21 2015
.SYNOPSIS...
LOW PRESSURE WILL AFFECT THE MID-ATLANTIC TODAY. HIGH PRESSURE
RETURNS THURSDAY AND FRIDAY. AREAS OF LOW PRESSURE MAY IMPACT THE
REGION SATURDAY AND MONDAY.
&&
.NEAR TERM /TODAY/...
MSAS ANALYSIS INDICATES SEVERAL WAVES OF LOW PRESSURE ACROSS THE
UPPER MIDWEST...OHIO VALLEY AND SOUTHWARD INTO THE CAROLINAS. IN THE
PAST HOUR OR TWO PRECIPITATION HAS BECOME MORE ROBUST ACROSS WESTERN
WV...WITH SOME ECHOS DEVELOPING OVER ERN WV AND WRN VA. THIS
PARTICULAR BATCH OF PRECIPITATION WAS NOT CAUGHT ON HI RES MODELS.
DURING THE DAY...LOW PRESSURE WILL BECOME MORE ORGANIZED AS IT
MOVES ACROSS OHIO INTO PA...WHILE A COASTAL LOW DEVELOPS OFFSHORE.
FORECAST PHILOSOPHY FOR MOST OF THE CWA REMAINS CONSISTENT WITH
PREVIOUS FORECAST UPDATES. GFS INDICATES BETTER CONVERGENCE AND
BANDING POTENTIAL OVER PENDLETON AND HIGHLAND COUNTIES...WHICH IS
ALSO INDICATED ON SOME RUNS OF THE HRRR AND TO A CERTAIN DEGREE ON
THE OOZ NAM FIRE WEATHER NEST. INCREASED SNOWFALL ACCUMULATIONS
AND EXTENDED WINTER WX ADVISORY TO INCLUDE THESE TWO COUNTIES.
PRECIP WILL MOVE ACROSS THE CWA THROUGH THE MORNING HOURS. EARLY
MORNING TEMPS ARE BELOW FREEZING ALMOST EVERYWHERE EXCEPT FOR
URBAN AND MARINE INFLUENCED AREAS. TEMPS WILL GRADUALLY RISE
DURING THE MORNING...WITH SUBFREEZING TEMPS HANGING ON THE LONGEST
OVER NRN MD WHERE WEDGE OF COOLER AIR FROM HIGH PRESSURE TO THE
NORTH WILL PERSIST. THIS AREA...AND THE HIGHLANDS...ARE FORECAST
TO HAVE THE HIGHEST SNOWFALL TOTALS OF AROUND 2-3 INCHES. AMOUNTS
DECREASE HEADING SOUTH...WITH AROUND AN INCH ACROSS THE DC METRO.
CONFIDENCE IN ACCUMULATING SNOW IS LOW FOR SOUTHERN MARYLAND INTO
CENTRAL VIRGINIA DUE TO WARMER TEMPERATURES AND RAIN MIXING IN.
&&
.SHORT TERM /TONIGHT/...
WINTER WEATHER ADVISORY ENDS AT 6 PM. THERE MAY BE SOME LINGERING
PRECIPITATION AN HOUR OR TWO BEYOND THIS IN PARTS OF MARYLAND NEAR
THE BAY PER LATEST MODEL TRENDS...BUT LOW PRESSURE SHOULD EXIT THE
AREA BY EARLY WEDNESDAY EVENING AND PROMOTE AN END TO PRECIPITATION.
WILL HAVE TO WATCH FOR A POTENTIAL RE-FREEZE. PATCHY DRIZZLE OR
FREEZING DRIZZLE IS POSSIBLE WEDNESDAY EVENING DUE TO SATURATED LOW
LEVELS AND COOLER AIR TRAPPED ABOVE THE SURFACE. THEREFORE...WET OR
SLUSHY ROADS MAY RE- FREEZE AS TEMPERATURES DROP BELOW FREEZING.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
"FAST FLOW IN A WRN RDG/ERN TROF" SORT OF SUMS UP A DECENT PART OF
THE XTND FCST. THE FIRST PART OF THE FCST IS RLVTLY PLACID AS HIGH
PRES SETTLES OVR THE AREA. HIGHS IN THE LM40S...LOWS IN THE M20S
XCPT WARMER IN THE CITIES.
WHILE NOTHING LOOKS AS AMPLIFIED AS IT DID LAST JAN THE MDLS ARE
STILL PROJECTING A RDG OVR THE WRN U.S. W/ RLVTLY FAST MOVG LOW
PRES AREAS COMING OUT OF AN ACTIVE SRN STRM. THE FIRST OF THESE
LOOKS TO IMPACT THE AREA FRI NGT/SAT. THERE ISN`T A LOT OF COLD
AIR ACROSS THE ERN U.S. BUT IF THE LOW TAKES A TRACK FM GA TO ORF
THAT WL KEEP THE CWA ON THE COLDER SIDE OF THINGS. ATTM BOTH GFS
AND EURO ARE KEEPING THE 850-1000MB TCKNS BTWN 1296-1300M...JUST
COLD ENOUGH TO HV CONCERNS THE PCPN COULD FALL AS WET SNOW. WE`LL
TRY TO FINE TUNE THE DETAILS IN THE DAYS TO COME.
AND IN THE FAST FLOW IT APPEARS THAT ANOTHER LOW PRES AREA WL DIVE
DOWN FM THE WRN RDG...OVR MN/WI SUN AND INTO THE MID ATLC SUN
NGT/MON. AGN THE TRACK LOOKS TO KEEP THE LOW S OF THE CWA...AND AGN
TEMP COLUMN LOOKS TO BE MARGINALLY COLD ENOUGH FOR CONCERNS OF
SNOW. MORE TO COME.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
SNOW OR A RAIN/SNOW MIX WILL OVERSPREAD THE TERMINALS THIS MORNING.
IFR CONDITIONS ARE EXPECTED. PRECIPITATION WILL MOVE OFF TO THE
NORTHEAST LATER IN THE AFTERNOON BUT IFR CONDITIONS MAY CONTINUE
THROUGH TONIGHT AS LOW-LEVEL MOISTURE REMAINS TRAPPED UNDERNEATH THE
SUBSIDENCE INVERSION.
HIGH PRESSURE BUILDS INTO THE AREA FOR THURSDAY/FRIDAY. LOW PRESSURE
MAY BRING PRECIP/FLIGHT RESTRICTIONS SATURDAY.
&&
.MARINE...
A COASTAL LOW WILL DEVELOP TODAY. SOME CHANNELING WILL DEVELOP WITH
GUSTS INTO THE TEENS...BUT NOT EXPECTING GUSTS TO SCA CRITERIA.
WINDS XPCTD TO BE BLO SCA VALUES THU/FRI AS HIGH PRES BUILDS INTO
THE AREA. AN AREA OF LOW PRES MAY IMPACT THE WATERS SAT...BRINGING
WINTRY PCPN.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 PM EST
THIS EVENING FOR DCZ001.
MD...WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 PM EST
THIS EVENING FOR MDZ004>006-011-013-014-503>508.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR MDZ003-
501-502.
VA...WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO 6 PM EST
THIS EVENING FOR VAZ053-054-505-506.
WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR VAZ028-
031.
WV...WINTER WEATHER ADVISORY UNTIL 6 PM EST THIS EVENING FOR
WVZ050>053-055-501>504.
MARINE...NONE.
&&
$$
PRODUCTS....KCS/WOODY!
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
619 PM EST THU JAN 22 2015
.AVIATION...
ADEQUATE MOISTURE TUCKED BENEATH A STRENGTHENING INVERSION WILL
RETAIN THE EXTENSIVE MVFR STRATUS DECK THROUGH AT LEAST THE EARLY
PORTION OF THE NIGHT. SOME QUESTION YET AS TO THE POTENTIAL FOR
SOME BREAKS AND/OR A GREATER DEGREE OF CLEARING TO EMERGE DURING THE
EARLY-MID MORNING PERIOD. DEFINED AREA OF CLEAR SKY NOW ENCOMPASSES
MUCH OF NORTHERN LOWER MI...AS WELL AS ACROSS CENTRAL LAKE MICHIGAN.
HOWEVER LOW LEVEL FLOW WILL VEER WITH TIME TOWARD A SOUTHEAST
DIRECTION...PROVIDING THE POTENTIAL FOR SOME MOISTURE ADVECTION TO
OCCUR WITHIN THE DEEPER LOW LEVEL MOISTURE PLUME STILL RESIDING
ACROSS NORTHERN IL. MODEL MOISTURE FIELDS FAVOR LEANING TOWARD THE
MORE PESSIMISTIC OUTLOOK. THIS KEEPS WITH THE GOING TAF
FORECAST...MVFR STRATUS AN ISSUE RIGHT INTO FRIDAY.
//DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILING BELOW 5000 FEET TONIGHT...MEDIUM ON FRIDAY.
&&
.PREV DISCUSSION...ISSUED 347 PM EST THU JAN 22 2015
SHORT TERM... THROUGH TONIGHT
MAIN FORECAST CHALLENGE IS WITH CLOUD COVER OVERNIGHT. SPLIT FLOW
PATTERN IN PLACE OVER NORTH AMERICA WITH SOUTHEAST MICHIGAN
POSITIONED IN THE POLEWARD ENTRANCE REGION OF A STRONG JET AXIS OVER
THE OHIO VALLEY. THIS WILL PROMOTE ACTIVE SUBSIDENCE THROUGH THE
PERIOD...AS EVIDENCED BY SPRAWLING SURFACE HIGH OVER THE WESTERN
GREAT LAKES. EXTENSIVE STRATUS DECK OVER THE UPPER MIDWEST HAS SHOWN
GOOD SIGNS OF CLEARING OVER WISCONSIN/UPPER MICHIGAN WITH BACK EDGE
OF THE STRATUS WORKING INTO NORTHERN MICHIGAN AND ACROSS LAKE
MICHIGAN. LINEAR EXTRAPOLATION OF THIS CLEARING WOULD WORK IT INTO
SOUTHEAST MICHIGAN AFTER 00Z. HOWEVER...CLIMATOLOGY IS A FACTOR
WORKING AGAINST CLEARING. NAM AND RAP RH PROGS ARE NOT MUCH HELP
HERE AS THEY DID NOT SHOW THE AREA OF CLEARING TO OUR WEST...HOWEVER
THEY DO SHOW POCKETS OF CLEARING OVER THE UPPER MIDWEST OVERNIGHT.
THE UPSHOT IS...TRENDED A BIT MORE OPTIMISTIC WITH CLOUD COVER THAN
PREVIOUS FORECAST...BUT KEPT PARTLY TO MOSTLY CLOUDY SKIES IN ORDER
THAT THE FORECAST NOT BOUNCE AROUND TOO MUCH AS CONFIDENCE IN
CLEARING SKIES IS STILL NOT HIGH.
CLOUD COVER WILL IMPACT LOW TEMPS AS WELL. SIDED WITH THE WARMER MET
MOS. SOME ROOM FOR TEMPS TO DROP BELOW FORECAST LOWS IF CLEARING IS
REALIZED...HOWEVER STILL THINK MAV MOS IS A BIT TOO LOW AS IT IS
UNDERDOING SURFACE DEWPOINTS. ALSO...INCREASING SW GRADIENT FLOW
TOWARD THE END OF THE FORECAST PERIOD SHOULD LIMIT POTENTIAL TEMP
DROP OVER NORTHERN PARTS OF THE FORECAST AREA. THE INCREASED
PRESSURE GRADIENT WILL OCCUR AS AN EXPANSIVE CYCLONE DEEPENS OVER
NORTHERN ONTARIO.
LONG TERM...FRIDAY THROUGH WEDNESDAY
UPPER LEVEL PATTERN BECOMES QUITE COMPLEX TO END THE WEEK. AMPLIFIED
RIDGING OVER THE WESTERN CONUS GET FOLDED OVER IN THE GREAT LAKES
FRIDAY WHICH TRIES TO PINCH OFF THE BASE OF THE TROUGH OVER THE FOUR
CORNERS. ENERGETIC SOUTHERN STREAM KEEPS IT FAIRLY PROGRESSIVE
PREVENTING A TRUE CUTOFF LOW FROM FORMING AS IT TRACKS ACROSS THE
SOUTHERN STATES. INCOMING NORTHERN STREAM ENERGY EVENTUALLY CARVES
OUT ANOTHER DOMINATE TROUGH BY THE END OF THE WEEKEND. AT THE
SFC...HIGH PRESSURE STRUNG OUT FROM THE CENTRAL PLAINS THROUGH THE
OHIO VALLEY AND TO THE EAST COAST ON FRIDAY WILL GET COMPRESSED
BETWEEN NORTHERN STREAM LOW TRACKING THROUGH NORTHERN ONTARIO AND
DEVELOPING SOUTHERN STREAM LOW UNDER THE AFOREMENTIONED PINCHED OFF
TROUGH. THE HIGH WILL MOVE OFF TO THE EAST BY SATURDAY AS THE
SYSTEMS DRAW NEARER EACH OTHER WITH THE ATTEMPTED PHASING OF THE
JETS. OVERALL THIS YIELDS A SOMEWHAT LOWER CONFIDENCE FORECAST AS
SLIGHT DIFFERENCES IN TIMING OF PHASING JETS OR LOCATION OF THE SFC
FEATURES USUALLY LEADS TO JUMPS IN THE FORECAST. LUCKILY IN THIS
CASE...THE PHASING IS ADVERTISED FAR ENOUGH DOWN STREAM TO NEGATE SOME
OF THE TYPICAL CONCERNS.
FOR FRIDAY...WITH HIGH PRESSURE LOCKED AT THE SFC...THE LOW PASSING
THROUGH ONTARIO WILL DROP A COLD FRONT/TROUGH THROUGH LOWER MI IN
THE AFTERNOON. WITH THE HIGH SLIDING TO OUR EAST...WINDS WILL BECOME
SOUTHWESTERLY IN THE MORNING AHEAD OF THE TROUGH AS THE RIDGE AND
TROUGH TIGHTEN THE PRESSURE GRADIENT OVER THE STATE. THESE SW WINDS
WILL BRING THE NOSE OF A THERMAL RIDGE INTO THE AREA THROUGH THE
AFTERNOON. THE WARM AIR WILL STEEPEN THE INVERSION BETWEEN 950-900MB
AS IT WARMS THE LAYER BETWEEN 700 AND 900MB. SO LOOK FOR ELEVATED
WINDS AROUND 15-20MPH WITH GUSTS TO AROUND 25MPH PEAKING IN THE
AFTERNOON. THE STOUT INVERSION WILL PREVENT BETTER MIXING FROM
BRINGING SOME OF THE HIGHER WINDS RIGHT ABOVE THE INVERSION DOWN TO
THE SFC.
THE WEAKENING COLD FRONT WILL ENTER CENTRAL MI AROUND MIDNIGHT WHICH
WILL BRING A CHANCE OF SNOW SHOWERS TO THE SAGINAW VALLEY AND
NORTHERN THUMB. MOISTURE POOLING AHEAD OF THE TROUGH IS DECENT WITH
PWATS INCREASING FROM UNDER 0.2 TO AROUND 0.5 INCHES. THE RIBBON OF
THETA E ALONG THE FRONT IS VERY NARROW WITH A GOOD GRADIENT ON THE
LEAD EDGE INITIALLY...BUT WEAKENING AS IT TRACKS THROUGH SOUTHERN
MI. SEE NO REASON TO DEVIATE FROM THE CHANCE/SLIGHT CHANCE POPS
RIGHT NOW FOR FRIDAY NIGHT. SEVERAL OTHER SMALL WAVES ARE ADVERTISED
TO SHOOT THROUGH THE DEVELOPING NW FLOW KEEPING LOW CHANCE POPS
THROUGH THE DAY SATURDAY. A SECOND...STRONGER COLD FRONT WILL DROP
INTO LOWER MI SATURDAY NIGHT STALLING ACROSS THE AREA AS THE
TRANSITION TO NW FLOW CONTINUES. WITH BL MOISTURE STILL PREVALENT
AND THE FRONT DRAPED ACROSS THE REGION WITH DECENT LAPSE RATES
THROUGH 800MB...WILL HOLD ONTO SOME LOW POP SNOW SHOWER MENTION
THROUGH SAT NIGHT.
CLIPPER DROPS OUT OF MANITOBA AND BEGINS INFLUENCING CONDITIONS
LATE SATURDAY NIGHT THROUGH SUNDAY. THIS SYSTEM COULD BRING IN
ANOTHER SHOT AT ACCUMULATING SNOW SUNDAY INTO EARLY MONDAY MORNING.
COLD AIR ADVECTION BEHIND THE FRONT ON MONDAY IS EXPECTED TO DROP
DAYTIME HIGH`S INTO THE TEENS AND LOW 20`S WITH SINGLE DIGIT
OVERNIGHT LOWS RETURNING FOR BOTH TUESDAY AND WEDNESDAY MORNING.
SCATTERED LIGHT SNOW SHOWERS WILL BE POSSIBLE ON THURSDAY AS ANOTHER
CLIPPER SWINGS THROUGH. TEMPS WARMING INTO THE LOW 30`S DURING THE
DAYLIGHT HOURS FOR THURSDAY AND FRIDAY.
MARINE...
A LOW PRESSURE SYSTEM TRACKING THROUGH CENTRAL CANADA WILL REACH
NORTHERN QUEBEC FRIDAY AFTERNOON. THIS SYSTEM WILL DROP A WEAKENING
COLD FRONT INTO THE REGION FRIDAY. THIS WILL TIGHTEN THE PRESSURE
GRADIENT BETWEEN IT AND THE EXITING SURFACE HIGH ALLOWING WINDS TO
AMPLIFY SOMEWHAT OVER CENTRAL AND NORTHERN LAKE HURON. THOUGH
SUSTAINED WINDS APPEAR TO REACH INTO THE MID 20 KNOT RANGE...WARM
AIR ALOFT AND A STEEP LOW LEVEL INVERSION APPEAR PREVENT STRONGER
GUSTS FROM REACHING THE SURFACE. FEEL FAIRLY CONFIDENT THAT WINDS
WILL GUST AT OR JUST ABOVE 30 KNOTS ACROSS NORTHERN AND CENTRAL LAKE
HURON. THOUGH GALE FORCE GUSTS CANNOT BE RULES OUT
ENTIRELY...CURRENT MODELS AND ANALYSIS SUGGEST WINDS TO THIS
STRENGTH WOULD BE QUITE SPORADIC...AND NOT WIDE SPREAD ENOUGH TO
WARRANT A GALE WARNING OR CONTINUING THE WATCH AT THIS TIME SO THE
WATCH HAS BEEN CANCELLED. EXTENSIVE ICE COVER IN THE LAKE HURON
NEARSHORE ZONES WILL PREVENT ANY WAVES DEVELOPING WITH THE OFFSHORE
FLOW TO AROUND 25 KNOTS...SO SMALL CRAFT ADVISORIES WILL NOT BE
NEEDED AT THIS TIME. COLD NORTHWEST FLOW THIS WEEKEND WILL KEEP
WINDS ELEVATED THROUGH THAT PERIOD...BUT WILL REMAIN BELOW GALE
FORCE.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....MR
SHORT TERM...DT
LONG TERM....DRK/DE
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1211 PM EST WED JAN 21 2015
.AVIATION...
A SLOW WEAKENING IN THE INTENSITY OF THE SNOW WILL OCCUR DURING THE
COURSE OF THE AFTERNOON PRIOR TO IT COMING TO AN END THIS EVENING.
DURING THIS PERIOD...THE MORE PERSISTENT SNOWFALL WILL IMPACT FNT
AND PTK. MBS WILL REMAIN ON THE NORTHERN FRINGE OF THE SNOW AND
SHOULD ACTUALLY SEE IT COME TO AN END OVER THE NEXT 2 TO 3 HOURS.
ADDITIONAL SNOW ACCUMULATIONS AT FNT AND MBS WILL BE AN INCH OR LESS
THROUGH THE AFTERNOON. THERE WILL HOWEVER BE QUITE A BIT OF
VARIABILITY IN CIGS AND VSBY WITH BRIEF INTERVALS OF HIGHER
INTENSITY SNOWFALL PERSISTING DURING THE AFTERNOON.
FOR DTW...THE LOWER VISIBILITIES IMPACTING METRO DETROIT ARE MORE
THE RESULT OF FOG THAN INTENSE SNOWFALL. WHILE SNOW SHOWERS WILL
PERSIST THROUGH THE AFTERNOON...ADDITIONAL ACCUMULATIONS SHOULD JUST
BE A DUSTING. ALTHOUGH SOME LOW LEVEL MOISTURE WILL ATTEMPT TO HOLD
INTO TONIGHT...THE DEGREE OF LOW LEVEL DRY AIR ADVECTION FROM THE
N-NE TONIGHT WILL REMAIN SUPPORTIVE OF THE CURRENT FORECAST IN
HOLDING CIGS ON THE LOW END VFR.
//DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILINGS BELOW 5000 FEET TODAY...MEDIUM TONIGHT.
* HIGH FOR PRECIPITATION AS ALL SNOW.
&&
.PREV DISCUSSION...ISSUED 1021 AM EST WED JAN 21 2015
UPDATE...
THE REGION OF WIDESPREAD SNOW HAS BEEN SLOWLY BUT STEADILY LIFTING
NORTHWARD OVER THE LAST COUPLE OF HOURS. RADAR AND SATELLITE ALONG
WITH THE LATEST RAP AND 12Z NAM INDICATE THIS IS BEING FORCED
WITHIN A RIBBON OF DEFORMATION JUST NORTH OF A SECONDARY MID
LEVEL VORTICITY MAX NOW ROTATING ACROSS THE SW MI/NRN INDIANA
BORDER. THIS MID LEVEL CIRCULATION IS EXPECTED TO SHEAR APART AS
IT WORKS INTO NW OHIO THIS AFTERNOON ALONG WITH THE LARGER MID
LEVEL VORTICITY CENTER TO THE SOUTH. THE TRACK OF THIS FEATURE AND
RECENT RADAR TRENDS SUGGEST THAT THE NORTHWARD PUSH TO THE BACK
EDGE OF THE HEAVIER SNOW WILL HALT AS IT ROTATES INTO THE NRN
DETROIT SUBURBS OVER THE NEXT COUPLE OF HOURS. THE MID LEVEL
DEFORMATION WILL THEN CONTRACT BEFORE ENDING DURING THE
AFTERNOON...FOCUSING THE BETTER LIFT BETWEEN THE I 96/696 AND I
69 CORRIDORS. THIS REGION IS LIKELY TO PICK UP AROUND AN
ADDITIONAL INCH THROUGH MID AFTERNOON. SOME ADDITIONAL SNOWFALL
ACCUMS UP TO TWO INCHES DO HOWEVER SEEM PROBABLE IN ANY LOCAL
WHERE THE MID LEVEL FORCING HOLDS ON JUST A BIT LONGER /MOST
LIKELY SOMEWHERE IN OAKLAND...MACOMB OR SOUTHERN ST CLAIR
COUNTIES/.
SFC OBS SUGGESTED SOME PATCHY FREEZING DRIZZLE NEAR THE OHIO
STATE LINE THIS MORNING. MID LEVEL MOISTURE APPEARS TO BE
INCREASING AGAIN SOUTH OF THE I 94 CORRIDOR. THIS SHOULD END ANY
FREEZING DRIZZLE AND SUPPORT JUST SNOW SHOWERS THROUGH EARLY
AFTERNOON...WITH LITTLE ADDITIONAL ACCUMS EXPECTED.
THE GOING FORECAST STILL HAS A GOOD HANDLE ON THE SITUATION
/ALTHOUGH SOME OF THE NORTHERN DETROIT SUBURBS MAY END UP WITH
TOTAL SNOWFALL AMOUNTS UP TO OR SLIGHTLY OVER THREE INCHES/. AN
UPDATE WILL BE ISSUED MAINLY TO MAKE SOME ADJUSTMENTS TO REFLECT
LATEST TRENDS ON TIMING.
PREV DISCUSSION...ISSUED 353 AM EST WED JAN 21 2015
SHORT TERM... TODAY AND TONIGHT
THE NEXT WAVE OF LOW PRESSURE MOVING THROUGH THE SOUTHERN GREAT
LAKES IS ON TRACK TO SPREAD ANOTHER PATTERN OF SNOW OVER SE MICHIGAN
DURING THE MORNING. MOST OF THE ACCUMULATION WILL ONCE AGAIN FALL
SOUTH OF MIDLAND...BAY CITY...AND THE NORTHERN THUMB WITH HIGHEST
AMOUNTS AROUND 2 INCHES FROM THE OHIO BORDER UP TO ABOUT THE I-96
CORRIDOR AND THEN TAPERING OFF TO THE NORTH FROM THERE. SIMILAR TO
YESTERDAY...EXPECT A PEAK IN RATES FROM ABOUT MID MORNING THROUGH
EARLY AFTERNOON BUT WITH LIGHT ACCUMULATION LINGERING LONGER TOWARD
EVENING. THE LONGER DURATION AND POTENTIAL FOR A MORE FOCUSED BURST
SHOULD RESULT IN A FEW MORE 2 INCH TOTALS COMPARED TO YESTERDAY.
SNOW WILL SPREAD NORTH OF THE OHIO BORDER SHORTLY AFTER PRESS TIME
AS THE FIRST PHASE OF FORCING GETS UNDERWAY. SATELLITE IMAGERY AND
MODEL ANALYSIS FIELDS INDICATE THE LEADING MID LEVEL CIRCULATION
OVER THE OHIO VALLEY BEFORE SUNRISE WILL HELP GET ISENTROPIC LIFT
STARTED OVER SE MICHIGAN AS THE MID LEVEL THETA-E RIDGE MOVES
NORTHWARD. MODEL SOUNDINGS AND CROSS SECTIONS OF THETA-E INDICATE
THIS PROCESS WILL OCCUR WITH MODERATE MOISTURE TRANSPORT AND
FAVORABLY LOW STABILITY THAT WILL SUPPORT A RAPID INCREASE IN
COVERAGE AND INTENSITY OF SNOW ALONG THE LEADING EDGE OF THE THETA-E
RIDGE AROUND 700 MB. THE MOISTURE AXIS WILL SPREAD NORTHWARD OVER
ABOUT THE SOUTH HALF OF THE AREA DURING THE MORNING BEFORE BEING
DRAWN BACK WESTWARD INTO THE PRIMARY MID LEVEL CIRCULATION. THIS
WILL SET UP A RESPECTABLY ORGANIZED TROWAL AXIS WITHIN WHICH A
HEAVIER BURST OF SNOW IS EXPECTED DURING MID TO LATE MORNING AS THE
MAIN UPPER CIRCULATION SHEARS THROUGH INDIANA AND OHIO. THE
STRONGEST RESPONSE SHOULD OCCUR ON THE SOUTH FLANK OF THE TROWAL
WHERE THE STABILITY PROFILE WILL BE MOST FAVORABLE AND DEFORMATION
STRONGEST...ROUGHLY ALONG AND SOUTH OF I-96 CORRIDOR AS THE BEST
ESTIMATE FOR NOW. IT IS ALSO IMPORTANT TO POINT OUT THE STRONGEST
FORCING WILL BE BRIEF AS THE TRACK OF THE MID LEVEL CIRCULATION WILL
CARRY FAVORABLE SYSTEM RELATIVE FLOW EASTWARD AND CAUSE THE TROWAL
TO WEAKEN OVER SE MICHIGAN DURING THE AFTERNOON. EXPECT SNOW WILL
NOT END COMPLETELY BUT WILL DIMINISH CONSIDERABLY TOWARD EVENING.
CONSIDERING THE THERMAL PROFILE AND SURFACE TEMPERATURES ARE SIMILAR
TO YESTERDAY...A 15 TO 1 RATIO IS USED AGAIN FOR PEAK ACCUMULATION
TOTALS AROUND 2 INCHES WHICH IS AT OR SLIGHTLY LESS THAN MODEL 12 HR
QPF OF 0.15 INCHES TO FACTOR IN THE UNCERTAINTY ON DURATION.
THERE IS A CHANCE OF LIGHT SNOW OR FLURRIES LINGERING INTO THE
EVENING BUT FORCING WILL BECOME MUCH MORE NEBULOUS WITHIN THE
REMNANT LARGER SCALE UPPER TROUGH AXIS. NEUTRAL DYNAMIC SUPPORT WILL
BE COUPLED WITH WEAK BUT NEGATIVE THETA-E ADVECTION IN THE 850 TO
700 MB LAYER OVERNIGHT WHICH WILL LEAD TO SOME BREAKS IN THE CLOUD
COVER AND TEMPS SETTLING INTO THE TEENS TO LOWER 20S BY SUNRISE
THURSDAY.
LONG TERM...
SW-NE UPPER LEVEL TROUGH/SHEAR AXIS WILL BE SWINGING THROUGH THE
GREAT LAKES REGION ON THURSDAY...BUT WITH A LARGE AREA OF SURFACE
HIGH PRESSURE TUCKED UNDERNEATH...NO BIG CONCERNS FOR MEASURABLE
PRECIPITATION...BUT WOULD NOT RULE OUT A FEW FLURRIES WITH FAIRLY
COLD AIRMASS (925 MB TEMPS IN THE UPPER NEGATIVE SINGLE NUMBERS/850
MB TEMPS AROUND -10 C). THIS COLD LOW LEVEL AIRMASS/SURFACE RIDGE
WILL LINGER INTO THURSDAY EVENING...WITH WARM ADVECTION/RETURN FLOW
AROUND THE DEPARTING HIGH/RIDGE AXIS BEGINNING TO INCREASE OVERNIGHT
THURSDAY...BUT STILL STRUGGLING TOWARD THE OHIO BORDER...AND
EXPECTING TEMPS TO FALL PREDOMINATELY INTO THE TEENS...WITH LOWER
20S OVER THE URBAN HEAT ISLAND OF DETROIT AND TOWARD TRI-CITIES
REGION...WHERE CONVERGENT SOUTHWEST FLOW EXPECTED TO HELP FACILITATE
DEVELOPING LOW CLOUDS OFF LAKE MICHIGAN. WITH STRENGTHENING WARM
ADVECTION SEEN AT THE 850 MB LEVEL...RISING TOWARD ZERO...BECOMING
MORE PESSIMISTIC FOR FRIDAY...AS EURO/NAM/GFS ALL SHOWING A GOOD
DEAL OF MOISTURE UNDERNEATH (950-925 MB)...AND WILL BE INCREASING
CLOUD COVER...BUT STILL THINK THE LOW LEVEL WARM ADVECTION WILL BE
ENOUGH TO WARM TEMPS JUST ABOVE THE FREEZING MARK AS SURFACE COLD
FRONT APPROACHES. THE WEAK COLD FRONT LOOKS TO BE SLIDING THROUGH
THE CENTRAL GREAT LAKES ON SATURDAY WITH LITTLE FANFARE/MARGINAL
UPPER LEVEL SUPPORT. LIGHT WESTERLY FLOW AND WEAK COLD ADVECTION
SATURDAY AFTERNOON WILL BE OFFSET A BIT BY DIURNAL IMPACT...WITH 925
MB TEMPS (-2.5 TO - 3 C) SUGGESTING MID TO UPPER 30S IS OBTAINABLE.
MARINE...
A RIDGE OF HIGH PRESSURE EXTENDING FROM HIGH PRESSURE OVER THE
MIDWEST WILL TRACK THROUGH THE CENTRAL GREAT LAKES OVER THE NEXT 24
TO 36 HOURS. AS THIS OCCURS...A BRIEF UPTICK IN NORTHWEST WINDS
LOOKS TO OCCUR OVER THE NORTHERN THIRD OF LAKE HURON THURSDAY
MORNING...WITH GUSTS UP AROUND 20 KNOTS. WINDS WILL SHIFT TO THE
SOUTHWEST THURSDAY NIGHT...AND INCREASE AS WE HEAD INTO FRIDAY AHEAD
OF A COLD FRONT. SUSTAINED WINDS OF 20 TO 25 KNOTS ARE EXPECTED OVER
THE CENTRAL PORTIONS OF LAKE HURON. HOWEVER...GUSTS SHOULD NOT BE
MUCH HIGHER AS WARMER AIR STREAMS IN...LEADING TO STABLE LOW LEVEL
PROFILES BY FRIDAY EVENING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SC
UPDATE.......SC
SHORT TERM...BT
LONG TERM....SF
MARINE.......SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1210 PM EST WED JAN 21 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 344 AM EST WED JAN 21 2015
UPPER MICHIGAN IS BETWEEN TWO SHORTWAVES EARLY THIS MORNING...WITH
ONE MOVING THROUGH SOUTHERN MINNESOTA AND NORTHEAST IOWA AND THE
OTHER ACROSS NORTHERN ONTARIO. THIS LEAVES THE CWA UNDER GENERALLY
QUIET CONDITIONS WITH THE FORECAST DEPENDENT ON SMALLER SCALE
FEATURES.
THE AREA OF LOW CLOUDS THAT ERODED OVER EASTERN AND CENTRAL UPPER
MICHIGAN YESTERDAY UNDER THE LIGHT NORTHEAST ASSOCIATED WITH A HIGH
PRESSURE RIDGE HAS BEEN SLOWLY MOVING EAST ACROSS CENTRAL UPPER
MICHIGAN AS 950-925MB WINDS ARE OUT OF THE WEST ON THE RAP ANALYSIS.
WITH WINDS ONLY AROUND 5KTS...THIS EASTWARD PROGRESSION WILL BE SLOW
THROUGH THE MORNING AND LIKELY OVERTAKEN THIS AFTERNOON BY THE WINDS
SHIFTING NORTHWEST OFF LAKE SUPERIOR BEHIND A SURFACE TROUGH. WHERE
SKIES HAVE BEEN CLEAR THIS MORNING...TEMPERATURES HAVE FALLEN INTO
THE SINGLE DIGITS BELOW ZERO OVER EASTERN UPPER MICHIGAN. BUT OVER
THE WESTERN U.P. WITH THE ABUNDANT LOW CLOUDS...TEMPERATURES ARE IN
THE UPPER TEENS TO LOWER 20S. AS CLOUDS MOVED OVERHEAD HERE AT THE
OFFICE...TEMPERATURES ROSE FROM -1F AT MIDNIGHT TO 12F AT 330AM.
THE WEAK SURFACE TROUGH CURRENTLY OVER WESTERN LAKE SUPERIOR WILL BE
THE MAIN CONTROLLING FACTOR FOR THE FORECAST TODAY. AS THIS TROUGH
SLOWLY SLIDES SOUTHEAST ACROSS THE AREA...THINK THERE WILL BE SOME
SNOW SHOWERS ASSOCIATED WITH THE SURFACE TROUGH THIS MORNING OVER
THE KEWEENAW AND THEN THAT WILL SHIFT SOUTHEAST ACROSS THE REST OF
WESTERN AND CENTRAL UPPER MICHIGAN THIS AFTERNOON/EVENING. WILL SHOW
ISOLATED/SCATTERED SNOW SHOWERS ALONG THE TROUGH AS IT MOVES THROUGH
THOSE AREAS. BEHIND THE TROUGH...WINDS WILL SHIFT TO THE NORTHWEST
AND THE LOW LEVEL THERMAL PROFILE WILL GRADUALLY COOL...LEADING TO
MORE FAVORABLE LAKE EFFECT CONDITIONS ON THE NW WIND SNOWBELTS.
DELTA-T VALUES ARE ONLY AROUND 13...WHICH IS ON THE LOW END FOR LAKE
EFFECT...AND WITH LOW LEVEL LAPSE RATES BEING FAIRLY WEAK (1000-
850MB LAPSE RATES AROUND 6-7C/KM)...WOULD NOT EXPECT THE LAKE EFFECT
TO GET TOO OUT OF HAND. DO GET A LITTLE HELP ALONG AND SHORTLY AFTER
THE TROUGH WITH SOME DEEPER MOISTURE. BUT THAT REALLY DIMINISHES
THROUGH THE NIGHT AS A SURFACE RIDGE NOSES INTO THE
AREA...STRENGTHENING THE SUBSIDENCE INVERSION (LOWERS TO 4-4.5KFT)
AND GRADUALLY BACKS WINDS TO THE WEST BY 12Z THURSDAY. THE AREA DOES
GET BRUSHED BY A SHORTWAVE MOVING THROUGH NORTHERN ONTARIO TONIGHT.
THIS SWEEPS A POCKET OF COLDER 850MB TEMPS (TO
-12C) SOUTHEAST ACROSS CENTRAL/EASTERN LAKE SUPERIOR DURING THE
NIGHT AND INCREASES THE LOW LEVEL WINDS SOME. WILL INCREASE THE POPS
OVER THE EAST AS THAT MOVES THROUGH...BUT STILL KEEP IN THE CHANCE
CATEGORY.
SNOW RATIOS SHOULD BE SIGNIFICANTLY LOWER THAN SEEN A COUPLE DAYS
AGO WITH ONLY TO TOP 1KFT OF THE CLOUD IN THE BOTTOM OF THE DGZ. THE
WINDS WILL BE LIGHT...WHICH WILL HELP KEEP THE FRACTURING DOWN...BUT
WITH MUCH OF THE FORCING BELOW THE DGZ WOULD EXPECT SNOW RATIOS
AROUND THE MID TEENS. THEREFORE THROUGH TONIGHT...HAVE SNOWFALL
AMOUNTS IN THE NW WIND SNOW BELTS OF A DUSTING TO AN INCH WITH A FEW
ISOLATED AMOUNTS HIGHER THAN THAT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 530 AM EST WED JAN 21 2015
A PERSISTENT RIDGE OVER THE WRN CONUS WILL MAINTAIN NW MID/UPPER
LEVEL FLOW ACROSS THE NRN GREAT LAKES THROUGH THE MIDDLE OF NEXT
WEEK. THIS WILL BRING A SERIES OF CLIPPERS INTO THE REGION. ONLY
LIGHT IF ANY LES IS EXPECTED WITH ONLY MARGINAL INSTABILITY AS THE
COLDEST AIR REMAINS OVER NE CANADA.
THU INTO THU NIGHT...AS THE 850 MB THERMAL TROUGH WITH TEMPS TO
AROUND -14C DEPARTS...THERE MAY BE SOME LINGERING SNOW SHOWERS INTO
THE NE CWA DURING THE MORNING. HOWEVER...WAA AND WINDS BACKING TO SW
WILL PUSH ANY REMAINING LES OFFSHORE. SW LOW LEVEL FLOW AND WAA WILL
INCREASE WITH A TIGHT GRADIENT BETWEEN A FCST 996 MB LOW MOVING INTO
NW ONTARIO AND 1030 MB RIDGE THROUGH THE SRN GREAT LAKES. EXPECT
STEADY OR SLOWLY RIDING TEMPS INTO THE LOW TO MID 20S.
FRI AND FRI NIGHT...THE WAA MAY BRING SOME PCPN INTO UPPER MI BUT
ANY AMOUNTS SHOULD BE LIGHT WITH QPF MAINLY AT OR BELOW 0.05
INCH(SNOW OF A HALF INCH OR LESS. MODELS 290K-295K FCST SUGGESTS
THAT THE BEST LIFT AND SATURATION WOULD OCCUR OVER THE ERN CWA DURING
THE AFTERNOON. HOWEVER...WITH A PROMINENT DRY 900-750 MB
LAYER...ONLY LOWER END 20-30 POPS WERE INCLUDED. COLDER AIR WILL
ONLY GRADUALLY MOVE IN FRI NIGHT WITH NW WINDS BEHIND A SFC TROUGH
AS 850 MB TEMPS ONLY DROP TO AROUND -6C BY 12Z/SAT. SOME LIGHT LAKE
ENHANCED SNOW IS POSSIBLE FOR NW FLOW FAVORED LOCATIONS AS A WEAK
SHORTWAVE MOVES THROUGH WITH DEEPER MOISTURE OVER THE AREA.
SAT...ONLY MARGINALLY COLD AIR WITH 850 MB TEMPS TO AROUND -10C WILL
MOVE IN AS A RIDGE BUILDS INTO THE WRN LAKES. DIMINISHING LOW LEVEL
WINDS THAT SLOWLY BECOME ACYC AND NRLY WILL ALSO LIMIT POTENTIAL FOR
LES ACCUMULATIONS CONSISTENT WITH ONLY CHANCE POPS.
SUN-TUE...THE GFS/ECMWF AND ENSEMBLES WERE IN REASONABLE AGREEMENT
THAT THE HEAVIER PCPN WITH THE NEXT STRONGER CLIPPER WILL REMAIN
WEST AND SOUTH OF UPPER MI WITH THE BEST SNOW CHANCE IF ANY INTO WRN
UPPER MI. CONFIDENCE WITH THE STRENGTH/POSITION OF THE NEXT SHRTWV
BY TUE IS MUCH LOWER GIVEN LARGE MODEL SPREAD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1208 PM EST WED JAN 21 2015
LOW END MVFR TO IFR CONDITIONS WILL PREVAIL AT ALL THREE TAF SITES
THROUGH THE PERIOD. THE ONLY EXCEPTION IS EARLY AT SAW...WHICH HAS
BEEN ABLE TO PUSH TO VFR AS LOWER CLOUDS ERODED AWAY.
THE BEST CHANCE FOR IFR CEILINGS/VIS WITH -SHSN WILL BE AT IWD AND
CMX WITH AND BEHIND A WEAK COLD FRONT SLIPPING ACROSS UPPER MI
TODAY. BORDERLINE IFR TO MVFR CEILINGS WILL LINGER INTO
THURSDAY...PARTICULARLY AT IWD AND CMX AS LAKE EFFECT SNOW SHOWERS
DEVELOP LATE THIS AFTERNOON. A MORE W TURN OF THE NEAR SFC WINDS
WILL DEVELOP AT IWD AROUND DAYBREAK...SHIFTING THE LOWER CEILINGS N
OF THE AIRPORT AND ALLOWING DRIER AIR TO WORK IN. THE MORE DOWNSLOPE
WINDS AT SAW SHOULD KEEP MAINLY MVFR CEILINGS THERE THROUGH THE
PERIOD.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 1208 PM EST WED JAN 21 2015
A WEAK TROUGH ACROSS E LAKE SUPERIOR WILL SLOWLY ERODE AS HIGH OVER
THE N PLAINS SINKS TO THE OHIO VALLEY THURSDAY AFTERNOON. A LOW
ACROSS N MANITOBA LATE THURSDAY WILL SWING ACROSS N ONTARIO AND INTO
QUEBEC FRIDAY AND FRIDAY NIGHT...WHILE DRAGGING A TROUGH ACROSS LAKE
SUPERIOR. SW GALES OF 35 TO NEAR 40KTS ARE EXPECTED OVER W AND N
CENTRAL LAKE SUPERIOR THURSDAY NIGHT INTO FRIDAY MORNING IN BETWEEN
THE EXITING RIDGE AND NEARING TROUGH. TEMPERATURES WILL BE FAIRLY
WARM...SO ALTHROUGH FREEZING SPRAY WILL BE POSSIBLE...THERE WILL
ONLY BE SMALL AREAS OF HEAVY FREEZING SPRAY LATE THURSDAY NIGHT.A
COLD FRONT WILL DROP ACROSS LAKE SUPERIOR FRIDAY AFTERNOON AND
EVENING...SHIFTING WINDS TO THE NORTHWEST UP TO 30KTS FOR SATURDAY.
LOOK FOR HIGH PRESSURE OVER N CENTRAL CANADA FRIDAY NIGHT PUSH
ACROSS ONTARIO SATURDAY NIGHT AND SUNDAY...BEFORE EXITING INTO
QUEBEC SUNDAY NIGHT. AT THE SAME TIME A LOW ACROSS N SASKATCHEWAN
SATURDAY SHOULD BE ABLE TO SINK ACROSS MINNESOTA AND WISCONSIN
SUNDAY MORNING...AND THE OHIO VALLEY BY LATE SUNDAY AFTERNOON.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING FOR
LSZ263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...KF
MARINE...KF
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1021 AM EST WED JAN 21 2015
.UPDATE...
THE REGION OF WIDESPREAD SNOW HAS BEEN SLOWLY BUT STEADILY LIFTING
NORTHWARD OVER THE LAST COUPLE OF HOURS. RADAR AND SATELLITE ALONG
WITH THE LATEST RAP AND 12Z NAM INDICATE THIS IS BEING FORCED
WITHIN A RIBBON OF DEFORMATION JUST NORTH OF A SECONDARY MID
LEVEL VORTICITY MAX NOW ROTATING ACROSS THE SW MI/NRN INDIANA
BORDER. THIS MID LEVEL CIRCULATION IS EXPECTED TO SHEAR APART AS
IT WORKS INTO NW OHIO THIS AFTERNOON ALONG WITH THE LARGER MID
LEVEL VORTICITY CENTER TO THE SOUTH. THE TRACK OF THIS FEATURE AND
RECENT RADAR TRENDS SUGGEST THAT THE NORTHWARD PUSH TO THE BACK
EDGE OF THE HEAVIER SNOW WILL HALT AS IT ROTATES INTO THE NRN
DETROIT SUBURBS OVER THE NEXT COUPLE OF HOURS. THE MID LEVEL
DEFORMATION WILL THEN CONTRACT BEFORE ENDING DURING THE
AFTERNOON...FOCUSING THE BETTER LIFT BETWEEN THE I 96/696 AND I
69 CORRIDORS. THIS REGION IS LIKELY TO PICK UP AROUND AN
ADDITIONAL INCH THROUGH MID AFTERNOON. SOME ADDITIONAL SNOWFALL
ACCUMS UP TO TWO INCHES DO HOWEVER SEEM PROBABLE IN ANY LOCAL
WHERE THE MID LEVEL FORCING HOLDS ON JUST A BIT LONGER /MOST
LIKELY SOMEWHERE IN OAKLAND...MACOMB OR SOUTHERN ST CLAIR
COUNTIES/.
SFC OBS SUGGESTED SOME PATCHY FREEZING DRIZZLE NEAR THE OHIO
STATE LINE THIS MORNING. MID LEVEL MOISTURE APPEARS TO BE
INCREASING AGAIN SOUTH OF THE I 94 CORRIDOR. THIS SHOULD END ANY
FREEZING DRIZZLE AND SUPPORT JUST SNOW SHOWERS THROUGH EARLY
AFTERNOON...WITH LITTLE ADDITIONAL ACCUMS EXPECTED.
THE GOING FORECAST STILL HAS A GOOD HANDLE ON THE SITUATION
/ALTHOUGH SOME OF THE NORTHERN DETROIT SUBURBS MAY END UP WITH
TOTAL SNOWFALL AMOUNTS UP TO OR SLIGHTLY OVER THREE INCHES/. AN
UPDATE WILL BE ISSUED MAINLY TO MAKE SOME ADJUSTMENTS TO REFLECT
LATEST TRENDS ON TIMING.
&&
.AVIATION...ISSUED 648 AM EST WED JAN 21 2015
A BAND OF SNOW WILL CONTINUE TO DEVELOP AND INTENSIFY OVER THE
TERMINAL CORRIDOR DURING THE MORNING. LIFR CONDITIONS WILL LIKELY BE
CONFINED TO THE SURFACE FRONT SOUTH OF THE OHIO BORDER...BUT SHORT
DURATION LIFR VISIBILITY RESTRICTION IS POSSIBLE IN THE HEAVIEST SNOW
SHOWERS. IFR WILL BE MORE PERSISTENT IN BOTH CEILING AND VISIBILITY
RESTRICTION THROUGH ABOUT MID AFTERNOON BEFORE BOTH SHOW IMPROVEMENT
TOWARD EVENING. FOLLOWING THE DEPARTURE OF THE LOW PRESSURE SYSTEM
TONIGHT...DRY AIR OBSERVED OVER SOUTHERN ONTARIO WILL BRING VFR
CONDITIONS AND POSSIBLY BREAK UP CLOUD COVER OVER SE MICHIGAN AS LOW
LEVEL WIND TURNS TOWARD THE NORTH.
FOR DTW... IFR SNOW WILL PERSIST THROUGH THE MORNING WITH A FEW
BURSTS OF LIFT RESTRICTION. TOTAL ACCUMULATION AROUND 2 INCHES
REMAINS ON TRACK BEFORE THE PATTERN WEAKENS TOWARD LATE AFTERNOON.
//DTW THRESHOLD PROBABILITIES...
* HIGH FOR CEILINGS AOB 5000 FEET TODAY...MEDIUM TONIGHT.
* HIGH FOR PRECIPITATION AS ALL SNOW.
* LOW FOR CEILING BELOW 200 FT AND/OR VISIBILITY LESS THAN 1/2SM.
&&
.PREV DISCUSSION...ISSUED 353 AM EST WED JAN 21 2015
SHORT TERM... TODAY AND TONIGHT
THE NEXT WAVE OF LOW PRESSURE MOVING THROUGH THE SOUTHERN GREAT
LAKES IS ON TRACK TO SPREAD ANOTHER PATTERN OF SNOW OVER SE MICHIGAN
DURING THE MORNING. MOST OF THE ACCUMULATION WILL ONCE AGAIN FALL
SOUTH OF MIDLAND...BAY CITY...AND THE NORTHERN THUMB WITH HIGHEST
AMOUNTS AROUND 2 INCHES FROM THE OHIO BORDER UP TO ABOUT THE I-96
CORRIDOR AND THEN TAPERING OFF TO THE NORTH FROM THERE. SIMILAR TO
YESTERDAY...EXPECT A PEAK IN RATES FROM ABOUT MID MORNING THROUGH
EARLY AFTERNOON BUT WITH LIGHT ACCUMULATION LINGERING LONGER TOWARD
EVENING. THE LONGER DURATION AND POTENTIAL FOR A MORE FOCUSED BURST
SHOULD RESULT IN A FEW MORE 2 INCH TOTALS COMPARED TO YESTERDAY.
SNOW WILL SPREAD NORTH OF THE OHIO BORDER SHORTLY AFTER PRESS TIME
AS THE FIRST PHASE OF FORCING GETS UNDERWAY. SATELLITE IMAGERY AND
MODEL ANALYSIS FIELDS INDICATE THE LEADING MID LEVEL CIRCULATION
OVER THE OHIO VALLEY BEFORE SUNRISE WILL HELP GET ISENTROPIC LIFT
STARTED OVER SE MICHIGAN AS THE MID LEVEL THETA-E RIDGE MOVES
NORTHWARD. MODEL SOUNDINGS AND CROSS SECTIONS OF THETA-E INDICATE
THIS PROCESS WILL OCCUR WITH MODERATE MOISTURE TRANSPORT AND
FAVORABLY LOW STABILITY THAT WILL SUPPORT A RAPID INCREASE IN
COVERAGE AND INTENSITY OF SNOW ALONG THE LEADING EDGE OF THE THETA-E
RIDGE AROUND 700 MB. THE MOISTURE AXIS WILL SPREAD NORTHWARD OVER
ABOUT THE SOUTH HALF OF THE AREA DURING THE MORNING BEFORE BEING
DRAWN BACK WESTWARD INTO THE PRIMARY MID LEVEL CIRCULATION. THIS
WILL SET UP A RESPECTABLY ORGANIZED TROWAL AXIS WITHIN WHICH A
HEAVIER BURST OF SNOW IS EXPECTED DURING MID TO LATE MORNING AS THE
MAIN UPPER CIRCULATION SHEARS THROUGH INDIANA AND OHIO. THE
STRONGEST RESPONSE SHOULD OCCUR ON THE SOUTH FLANK OF THE TROWAL
WHERE THE STABILITY PROFILE WILL BE MOST FAVORABLE AND DEFORMATION
STRONGEST...ROUGHLY ALONG AND SOUTH OF I-96 CORRIDOR AS THE BEST
ESTIMATE FOR NOW. IT IS ALSO IMPORTANT TO POINT OUT THE STRONGEST
FORCING WILL BE BRIEF AS THE TRACK OF THE MID LEVEL CIRCULATION WILL
CARRY FAVORABLE SYSTEM RELATIVE FLOW EASTWARD AND CAUSE THE TROWAL
TO WEAKEN OVER SE MICHIGAN DURING THE AFTERNOON. EXPECT SNOW WILL
NOT END COMPLETELY BUT WILL DIMINISH CONSIDERABLY TOWARD EVENING.
CONSIDERING THE THERMAL PROFILE AND SURFACE TEMPERATURES ARE SIMILAR
TO YESTERDAY...A 15 TO 1 RATIO IS USED AGAIN FOR PEAK ACCUMULATION
TOTALS AROUND 2 INCHES WHICH IS AT OR SLIGHTLY LESS THAN MODEL 12 HR
QPF OF 0.15 INCHES TO FACTOR IN THE UNCERTAINTY ON DURATION.
THERE IS A CHANCE OF LIGHT SNOW OR FLURRIES LINGERING INTO THE
EVENING BUT FORCING WILL BECOME MUCH MORE NEBULOUS WITHIN THE
REMNANT LARGER SCALE UPPER TROUGH AXIS. NEUTRAL DYNAMIC SUPPORT WILL
BE COUPLED WITH WEAK BUT NEGATIVE THETA-E ADVECTION IN THE 850 TO
700 MB LAYER OVERNIGHT WHICH WILL LEAD TO SOME BREAKS IN THE CLOUD
COVER AND TEMPS SETTLING INTO THE TEENS TO LOWER 20S BY SUNRISE
THURSDAY.
LONG TERM...
SW-NE UPPER LEVEL TROUGH/SHEAR AXIS WILL BE SWINGING THROUGH THE
GREAT LAKES REGION ON THURSDAY...BUT WITH A LARGE AREA OF SURFACE
HIGH PRESSURE TUCKED UNDERNEATH...NO BIG CONCERNS FOR MEASURABLE
PRECIPITATION...BUT WOULD NOT RULE OUT A FEW FLURRIES WITH FAIRLY
COLD AIRMASS (925 MB TEMPS IN THE UPPER NEGATIVE SINGLE NUMBERS/850
MB TEMPS AROUND -10 C). THIS COLD LOW LEVEL AIRMASS/SURFACE RIDGE
WILL LINGER INTO THURSDAY EVENING...WITH WARM ADVECTION/RETURN FLOW
AROUND THE DEPARTING HIGH/RIDGE AXIS BEGINNING TO INCREASE OVERNIGHT
THURSDAY...BUT STILL STRUGGLING TOWARD THE OHIO BORDER...AND
EXPECTING TEMPS TO FALL PREDOMINATELY INTO THE TEENS...WITH LOWER
20S OVER THE URBAN HEAT ISLAND OF DETROIT AND TOWARD TRI-CITIES
REGION...WHERE CONVERGENT SOUTHWEST FLOW EXPECTED TO HELP FACILITATE
DEVELOPING LOW CLOUDS OFF LAKE MICHIGAN. WITH STRENGTHENING WARM
ADVECTION SEEN AT THE 850 MB LEVEL...RISING TOWARD ZERO...BECOMING
MORE PESSIMISTIC FOR FRIDAY...AS EURO/NAM/GFS ALL SHOWING A GOOD
DEAL OF MOISTURE UNDERNEATH (950-925 MB)...AND WILL BE INCREASING
CLOUD COVER...BUT STILL THINK THE LOW LEVEL WARM ADVECTION WILL BE
ENOUGH TO WARM TEMPS JUST ABOVE THE FREEZING MARK AS SURFACE COLD
FRONT APPROACHES. THE WEAK COLD FRONT LOOKS TO BE SLIDING THROUGH
THE CENTRAL GREAT LAKES ON SATURDAY WITH LITTLE FANFARE/MARGINAL
UPPER LEVEL SUPPORT. LIGHT WESTERLY FLOW AND WEAK COLD ADVECTION
SATURDAY AFTERNOON WILL BE OFFSET A BIT BY DIURNAL IMPACT...WITH 925
MB TEMPS (-2.5 TO - 3 C) SUGGESTING MID TO UPPER 30S IS OBTAINABLE.
MARINE...
A RIDGE OF HIGH PRESSURE EXTENDING FROM HIGH PRESSURE OVER THE
MIDWEST WILL TRACK THROUGH THE CENTRAL GREAT LAKES OVER THE NEXT 24
TO 36 HOURS. AS THIS OCCURS...A BRIEF UPTICK IN NORTHWEST WINDS
LOOKS TO OCCUR OVER THE NORTHERN THIRD OF LAKE HURON THURSDAY
MORNING...WITH GUSTS UP AROUND 20 KNOTS. WINDS WILL SHIFT TO THE
SOUTHWEST THURSDAY NIGHT...AND INCREASE AS WE HEAD INTO FRIDAY AHEAD
OF A COLD FRONT. SUSTAINED WINDS OF 20 TO 25 KNOTS ARE EXPECTED OVER
THE CENTRAL PORTIONS OF LAKE HURON. HOWEVER...GUSTS SHOULD NOT BE
MUCH HIGHER AS WARMER AIR STREAMS IN...LEADING TO STABLE LOW LEVEL
PROFILES BY FRIDAY EVENING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......SC
AVIATION.....BT
SHORT TERM...BT
LONG TERM....SF
MARINE.......SF
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
643 AM EST WED JAN 21 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 344 AM EST WED JAN 21 2015
UPPER MICHIGAN IS BETWEEN TWO SHORTWAVES EARLY THIS MORNING...WITH
ONE MOVING THROUGH SOUTHERN MINNESOTA AND NORTHEAST IOWA AND THE
OTHER ACROSS NORTHERN ONTARIO. THIS LEAVES THE CWA UNDER GENERALLY
QUIET CONDITIONS WITH THE FORECAST DEPENDENT ON SMALLER SCALE
FEATURES.
THE AREA OF LOW CLOUDS THAT ERODED OVER EASTERN AND CENTRAL UPPER
MICHIGAN YESTERDAY UNDER THE LIGHT NORTHEAST ASSOCIATED WITH A HIGH
PRESSURE RIDGE HAS BEEN SLOWLY MOVING EAST ACROSS CENTRAL UPPER
MICHIGAN AS 950-925MB WINDS ARE OUT OF THE WEST ON THE RAP ANALYSIS.
WITH WINDS ONLY AROUND 5KTS...THIS EASTWARD PROGRESSION WILL BE SLOW
THROUGH THE MORNING AND LIKELY OVERTAKEN THIS AFTERNOON BY THE WINDS
SHIFTING NORTHWEST OFF LAKE SUPERIOR BEHIND A SURFACE TROUGH. WHERE
SKIES HAVE BEEN CLEAR THIS MORNING...TEMPERATURES HAVE FALLEN INTO
THE SINGLE DIGITS BELOW ZERO OVER EASTERN UPPER MICHIGAN. BUT OVER
THE WESTERN U.P. WITH THE ABUNDANT LOW CLOUDS...TEMPERATURES ARE IN
THE UPPER TEENS TO LOWER 20S. AS CLOUDS MOVED OVERHEAD HERE AT THE
OFFICE...TEMPERATURES ROSE FROM -1F AT MIDNIGHT TO 12F AT 330AM.
THE WEAK SURFACE TROUGH CURRENTLY OVER WESTERN LAKE SUPERIOR WILL BE
THE MAIN CONTROLLING FACTOR FOR THE FORECAST TODAY. AS THIS TROUGH
SLOWLY SLIDES SOUTHEAST ACROSS THE AREA...THINK THERE WILL BE SOME
SNOW SHOWERS ASSOCIATED WITH THE SURFACE TROUGH THIS MORNING OVER
THE KEWEENAW AND THEN THAT WILL SHIFT SOUTHEAST ACROSS THE REST OF
WESTERN AND CENTRAL UPPER MICHIGAN THIS AFTERNOON/EVENING. WILL SHOW
ISOLATED/SCATTERED SNOW SHOWERS ALONG THE TROUGH AS IT MOVES THROUGH
THOSE AREAS. BEHIND THE TROUGH...WINDS WILL SHIFT TO THE NORTHWEST
AND THE LOW LEVEL THERMAL PROFILE WILL GRADUALLY COOL...LEADING TO
MORE FAVORABLE LAKE EFFECT CONDITIONS ON THE NW WIND SNOWBELTS.
DELTA-T VALUES ARE ONLY AROUND 13...WHICH IS ON THE LOW END FOR LAKE
EFFECT...AND WITH LOW LEVEL LAPSE RATES BEING FAIRLY WEAK (1000-
850MB LAPSE RATES AROUND 6-7C/KM)...WOULD NOT EXPECT THE LAKE EFFECT
TO GET TOO OUT OF HAND. DO GET A LITTLE HELP ALONG AND SHORTLY AFTER
THE TROUGH WITH SOME DEEPER MOISTURE. BUT THAT REALLY DIMINISHES
THROUGH THE NIGHT AS A SURFACE RIDGE NOSES INTO THE
AREA...STRENGTHENING THE SUBSIDENCE INVERSION (LOWERS TO 4-4.5KFT)
AND GRADUALLY BACKS WINDS TO THE WEST BY 12Z THURSDAY. THE AREA DOES
GET BRUSHED BY A SHORTWAVE MOVING THROUGH NORTHERN ONTARIO TONIGHT.
THIS SWEEPS A POCKET OF COLDER 850MB TEMPS (TO
-12C) SOUTHEAST ACROSS CENTRAL/EASTERN LAKE SUPERIOR DURING THE
NIGHT AND INCREASES THE LOW LEVEL WINDS SOME. WILL INCREASE THE POPS
OVER THE EAST AS THAT MOVES THROUGH...BUT STILL KEEP IN THE CHANCE
CATEGORY.
SNOW RATIOS SHOULD BE SIGNIFICANTLY LOWER THAN SEEN A COUPLE DAYS
AGO WITH ONLY TO TOP 1KFT OF THE CLOUD IN THE BOTTOM OF THE DGZ. THE
WINDS WILL BE LIGHT...WHICH WILL HELP KEEP THE FRACTURING DOWN...BUT
WITH MUCH OF THE FORCING BELOW THE DGZ WOULD EXPECT SNOW RATIOS
AROUND THE MID TEENS. THEREFORE THROUGH TONIGHT...HAVE SNOWFALL
AMOUNTS IN THE NW WIND SNOW BELTS OF A DUSTING TO AN INCH WITH A FEW
ISOLATED AMOUNTS HIGHER THAN THAT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 530 AM EST WED JAN 21 2015
A PERSISTENT RIDGE OVER THE WRN CONUS WILL MAINTAIN NW MID/UPPER
LEVEL FLOW ACROSS THE NRN GREAT LAKES THROUGH THE MIDDLE OF NEXT
WEEK. THIS WILL BRING A SERIES OF CLIPPERS INTO THE REGION. ONLY
LIGHT IF ANY LES IS EXPECTED WITH ONLY MARGINAL INSTABILITY AS THE
COLDEST AIR REMAINS OVER NE CANADA.
THU INTO THU NIGHT...AS THE 850 MB THERMAL TROUGH WITH TEMPS TO
AROUND -14C DEPARTS...THERE MAY BE SOME LINGERING SNOW SHOWERS INTO
THE NE CWA DURING THE MORNING. HOWEVER...WAA AND WINDS BACKING TO SW
WILL PUSH ANY REMAINING LES OFFSHORE. SW LOW LEVEL FLOW AND WAA WILL
INCREASE WITH A TIGHT GRADIENT BETWEEN A FCST 996 MB LOW MOVING INTO
NW ONTARIO AND 1030 MB RIDGE THROUGH THE SRN GREAT LAKES. EXPECT
STEADY OR SLOWLY RIDING TEMPS INTO THE LOW TO MID 20S.
FRI AND FRI NIGHT...THE WAA MAY BRING SOME PCPN INTO UPPER MI BUT
ANY AMOUNTS SHOULD BE LIGHT WITH QPF MAINLY AT OR BELOW 0.05
INCH(SNOW OF A HALF INCH OR LESS. MODELS 290K-295K FCST SUGGESTS
THAT THE BEST LIFT AND SATURATION WOULD OCCUR OVER THE ERN CWA DURING
THE AFTERNOON. HOWEVER...WITH A PROMINENT DRY 900-750 MB
LAYER...ONLY LOWER END 20-30 POPS WERE INCLUDED. COLDER AIR WILL
ONLY GRADUALLY MOVE IN FRI NIGHT WITH NW WINDS BEHIND A SFC TROUGH
AS 850 MB TEMPS ONLY DROP TO AROUND -6C BY 12Z/SAT. SOME LIGHT LAKE
ENHANCED SNOW IS POSSIBLE FOR NW FLOW FAVORED LOCATIONS AS A WEAK
SHORTWAVE MOVES THROUGH WITH DEEPER MOISTURE OVER THE AREA.
SAT...ONLY MARGINALLY COLD AIR WITH 850 MB TEMPS TO AROUND -10C WILL
MOVE IN AS A RIDGE BUILDS INTO THE WRN LAKES. DIMINISHING LOW LEVEL
WINDS THAT SLOWLY BECOME ACYC AND NRLY WILL ALSO LIMIT POTENTIAL FOR
LES ACCUMULATIONS CONSISTENT WITH ONLY CHANCE POPS.
SUN-TUE...THE GFS/ECMWF AND ENSEMBLES WERE IN REASONABLE AGREEMENT
THAT THE HEAVIER PCPN WITH THE NEXT STRONGER CLIPPER WILL REMAIN
WEST AND SOUTH OF UPPER MI WITH THE BEST SNOW CHANCE IF ANY INTO WRN
UPPER MI. CONFIDENCE WITH THE STRENGTH/POSITION OF THE NEXT SHRTWV
BY TUE IS MUCH LOWER GIVEN LARGE MODEL SPREAD.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 643 AM EST WED JAN 21 2015
LOW END MVFR TO IFR CONDITIONS WILL PREVAIL AT ALL THREE TAF SITES
THROUGH THE PERIOD. A WEAK COLD FRONT JUST STARTING TO MOVE INTO
WESTERN UPPER MICHIGAN WILL SLOWLY SLIDE SOUTHEAST ACROSS THE U.P.
TODAY. AS THIS OCCURS...IT WILL BRING ISOLATED/SCATTERED SNOW
SHOWERS LATE THIS MORNING AND EARLY AFTERNOON OVER THE WEST. BASED
OFF UPSTREAM OBSERVATIONS IN NORTHERN MINNESOTA...CONTINUED TO SHOW
IFR CEILINGS/VISIBILITIES WITH THE INITIAL SNOWFALL. THERE MAY BE A
PERIOD OF INCREASING VISIBILITIES LATER THIS AFTERNOON BEFORE THE
LAKE EFFECT SNOW SHOWERS DEVELOP AND CONTINUE THROUGH THE EVENING.
AS DRIER AIR WORKS IN AND WINDS GRADUALLY BACK TOWARDS THE
WEST...SHOULD SEE THE LAKE EFFECT DIMINISH OVERNIGHT.
AT KSAW...MINE EFFECT SNOW DEVELOPED EARLY THIS MORNING AND
IMPACTED THE SITE FOR A COUPLE HOURS. NOW THAT LOW LEVEL WINDS HAVE
SHIFTED A LITTLE MORE OUT OF THE NORTH-NORTHWEST...THAT BAND OF
SNOW HAS MOVED SOUTH OF THE SITE. THUS...WOULD JUST EXPECT THE LOW
END MVFR CEILINGS AND OCCASIONAL FLURRIES FOR MUCH OF THE DAY. ONCE
THE FRONT MOVES THROUGH...DID SHOW A PERIOD OF IFR CEILINGS...BUT
EXPECT THAT TO BE SHORT LIVED AS WINDS BACK TO A DOWNSLOPING
NORTHWESTERLY DIRECTION.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 344 AM EST WED JAN 21 2015
A WEAK SURFACE TROUGH OVER WESTERN LAKE SUPERIOR WILL SLOWLY DROP
SOUTHEAST TODAY...WHICH WILL SHIFT WINDS TO THE NORTHWEST UP TO
20KTS. A HIGH PRESSURE RIDGE WILL MOVE ACROSS THE UPPER GREAT LAKES
REGION TONIGHT AND THURSDAY MORNING...LEADING TO WINDS GRADUALLY
BACKING. WINDS WILL BACK TO THE SOUTHWEST THURSDAY AFTERNOON AND
INCREASE AHEAD OF A LOW PRESSURE SYSTEM MOVING SOUTHEAST THROUGH
CENTRAL CANADA. THIS WILL LEAD TO THE POTENTIAL FOR SOUTHWESTERLY
GALE FORCE GUSTS TO 35KTS OVER WESTERN AND CENTRAL LAKE SUPERIOR
THURSDAY NIGHT INTO FRIDAY MORNING. A GALE WATCH HAS BEEN ISSUED
FOR THAT PERIOD. A COLD FRONT WILL DROP ACROSS LAKE SUPERIOR FRIDAY
AFTERNOON AND EVENING...SHIFTING WINDS TO THE NORTHWEST UP TO 30KTS
FOR SATURDAY. AN AREA OF HIGH PRESSURE MOVING OVER NORTHERN ONTARIO
ON SATURDAY WILL LEAD TO WEAKENING AND VEERING WINDS SATURDAY NIGHT.
A LOW PRESSURE SYSTEM MOVING SOUTHEAST ACROSS MINNESOTA AND NORTHERN
ILLINOIS LATE SATURDAY NIGHT AND SUNDAY WILL DRAG A TROUGH ACROSS
LAKE SUPERIOR SUNDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING FOR
LSZ263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
530 AM EST WED JAN 21 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 344 AM EST WED JAN 21 2015
UPPER MICHIGAN IS BETWEEN TWO SHORTWAVES EARLY THIS MORNING...WITH
ONE MOVING THROUGH SOUTHERN MINNESOTA AND NORTHEAST IOWA AND THE
OTHER ACROSS NORTHERN ONTARIO. THIS LEAVES THE CWA UNDER GENERALLY
QUIET CONDITIONS WITH THE FORECAST DEPENDENT ON SMALLER SCALE
FEATURES.
THE AREA OF LOW CLOUDS THAT ERODED OVER EASTERN AND CENTRAL UPPER
MICHIGAN YESTERDAY UNDER THE LIGHT NORTHEAST ASSOCIATED WITH A HIGH
PRESSURE RIDGE HAS BEEN SLOWLY MOVING EAST ACROSS CENTRAL UPPER
MICHIGAN AS 950-925MB WINDS ARE OUT OF THE WEST ON THE RAP ANALYSIS.
WITH WINDS ONLY AROUND 5KTS...THIS EASTWARD PROGRESSION WILL BE SLOW
THROUGH THE MORNING AND LIKELY OVERTAKEN THIS AFTERNOON BY THE WINDS
SHIFTING NORTHWEST OFF LAKE SUPERIOR BEHIND A SURFACE TROUGH. WHERE
SKIES HAVE BEEN CLEAR THIS MORNING...TEMPERATURES HAVE FALLEN INTO
THE SINGLE DIGITS BELOW ZERO OVER EASTERN UPPER MICHIGAN. BUT OVER
THE WESTERN U.P. WITH THE ABUNDANT LOW CLOUDS...TEMPERATURES ARE IN
THE UPPER TEENS TO LOWER 20S. AS CLOUDS MOVED OVERHEAD HERE AT THE
OFFICE...TEMPERATURES ROSE FROM -1F AT MIDNIGHT TO 12F AT 330AM.
THE WEAK SURFACE TROUGH CURRENTLY OVER WESTERN LAKE SUPERIOR WILL BE
THE MAIN CONTROLLING FACTOR FOR THE FORECAST TODAY. AS THIS TROUGH
SLOWLY SLIDES SOUTHEAST ACROSS THE AREA...THINK THERE WILL BE SOME
SNOW SHOWERS ASSOCIATED WITH THE SURFACE TROUGH THIS MORNING OVER
THE KEWEENAW AND THEN THAT WILL SHIFT SOUTHEAST ACROSS THE REST OF
WESTERN AND CENTRAL UPPER MICHIGAN THIS AFTERNOON/EVENING. WILL SHOW
ISOLATED/SCATTERED SNOW SHOWERS ALONG THE TROUGH AS IT MOVES THROUGH
THOSE AREAS. BEHIND THE TROUGH...WINDS WILL SHIFT TO THE NORTHWEST
AND THE LOW LEVEL THERMAL PROFILE WILL GRADUALLY COOL...LEADING TO
MORE FAVORABLE LAKE EFFECT CONDITIONS ON THE NW WIND SNOWBELTS.
DELTA-T VALUES ARE ONLY AROUND 13...WHICH IS ON THE LOW END FOR LAKE
EFFECT...AND WITH LOW LEVEL LAPSE RATES BEING FAIRLY WEAK (1000-
850MB LAPSE RATES AROUND 6-7C/KM)...WOULD NOT EXPECT THE LAKE EFFECT
TO GET TOO OUT OF HAND. DO GET A LITTLE HELP ALONG AND SHORTLY AFTER
THE TROUGH WITH SOME DEEPER MOISTURE. BUT THAT REALLY DIMINISHES
THROUGH THE NIGHT AS A SURFACE RIDGE NOSES INTO THE
AREA...STRENGTHENING THE SUBSIDENCE INVERSION (LOWERS TO 4-4.5KFT)
AND GRADUALLY BACKS WINDS TO THE WEST BY 12Z THURSDAY. THE AREA DOES
GET BRUSHED BY A SHORTWAVE MOVING THROUGH NORTHERN ONTARIO TONIGHT.
THIS SWEEPS A POCKET OF COLDER 850MB TEMPS (TO
-12C) SOUTHEAST ACROSS CENTRAL/EASTERN LAKE SUPERIOR DURING THE
NIGHT AND INCREASES THE LOW LEVEL WINDS SOME. WILL INCREASE THE POPS
OVER THE EAST AS THAT MOVES THROUGH...BUT STILL KEEP IN THE CHANCE
CATEGORY.
SNOW RATIOS SHOULD BE SIGNIFICANTLY LOWER THAN SEEN A COUPLE DAYS
AGO WITH ONLY TO TOP 1KFT OF THE CLOUD IN THE BOTTOM OF THE DGZ. THE
WINDS WILL BE LIGHT...WHICH WILL HELP KEEP THE FRACTURING DOWN...BUT
WITH MUCH OF THE FORCING BELOW THE DGZ WOULD EXPECT SNOW RATIOS
AROUND THE MID TEENS. THEREFORE THROUGH TONIGHT...HAVE SNOWFALL
AMOUNTS IN THE NW WIND SNOW BELTS OF A DUSTING TO AN INCH WITH A FEW
ISOLATED AMOUNTS HIGHER THAN THAT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 530 AM EST WED JAN 21 2015
A PERSISTENT RIDGE OVER THE WRN CONUS WILL MAINTAIN NW MID/UPPER
LEVEL FLOW ACROSS THE NRN GREAT LAKES THROUGH THE MIDDLE OF NEXT
WEEK. THIS WILL BRING A SERIES OF CLIPPERS INTO THE REGION. ONLY
LIGHT IF ANY LES IS EXPECTED WITH ONLY MARGINAL INSTABILITY AS THE
COLDEST AIR REMAINS OVER NE CANADA.
THU INTO THU NIGHT...AS THE 850 MB THERMAL TROUGH WITH TEMPS TO
AROUND -14C DEPARTS...THERE MAY BE SOME LINGERING SNOW SHOWERS INTO
THE NE CWA DURING THE MORNING. HOWEVER...WAA AND WINDS BACKING TO SW
WILL PUSH ANY REMAINING LES OFFSHORE. SW LOW LEVEL FLOW AND WAA WILL
INCREASE WITH A TIGHT GRADIENT BETWEEN A FCST 996 MB LOW MOVING INTO
NW ONTARIO AND 1030 MB RIDGE THROUGH THE SRN GREAT LAKES. EXPECT
STEADY OR SLOWLY RIDING TEMPS INTO THE LOW TO MID 20S.
FRI AND FRI NIGHT...THE WAA MAY BRING SOME PCPN INTO UPPER MI BUT
ANY AMOUNTS SHOULD BE LIGHT WITH QPF MAINLY AT OR BELOW 0.05
INCH(SNOW OF A HALF INCH OR LESS. MODELS 290K-295K FCST SUGGESTS
THAT THE BEST LIFT AND SATURATION WOULD OCCUR OVER THE ERN CWA DURING
THE AFTERNOON. HOWEVER...WITH A PROMINENT DRY 900-750 MB
LAYER...ONLY LOWER END 20-30 POPS WERE INCLUDED. COLDER AIR WILL
ONLY GRADUALLY MOVE IN FRI NIGHT WITH NW WINDS BEHIND A SFC TROUGH
AS 850 MB TEMPS ONLY DROP TO AROUND -6C BY 12Z/SAT. SOME LIGHT LAKE
ENHANCED SNOW IS POSSIBLE FOR NW FLOW FAVORED LOCATIONS AS A WEAK
SHORTWAVE MOVES THROUGH WITH DEEPER MOISTURE OVER THE AREA.
SAT...ONLY MARGINALLY COLD AIR WITH 850 MB TEMPS TO AROUND -10C WILL
MOVE IN AS A RIDGE BUILDS INTO THE WRN LAKES. DIMINISHING LOW LEVEL
WINDS THAT SLOWLY BECOME ACYC AND NRLY WILL ALSO LIMIT POTENTIAL FOR
LES ACCUMULATIONS CONSISTENT WITH ONLY CHANCE POPS.
SUN-TUE...THE GFS/ECMWF AND ENSEMBLES WERE IN REASONABLE AGREEMENT
THAT THE HEAVIER PCPN WITH THE NEXT STRONGER CLIPPER WILL REMAIN
WEST AND SOUTH OF UPPER MI WITH THE BEST SNOW CHANCE IF ANY INTO WRN
UPPER MI. CONFIDENCE WITH THE STRENGTH/POSITION OF THE NEXT SHRTWV
BY TUE IS MUCH LOWER GIVEN LARGE MODEL SPREAD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1226 AM EST WED JAN 21 2015
EXPECT MOCLR SKIES/VFR CONDITIONS AT SAW EARLY IN THE TAF PERIOD
WITH LINGERING LLVL DRY AIR TO GIVE WAY TO MORE CLDS/MVFR CONDITIONS
AS THE FLOW JUST ABOVE THE SFC SHIFTS TO A NW DIRECTION THAT WL DRAG
MORE SC TO DRIFT BACK INTO THE AREA. AT CMX AND IWD...PREDOMINANT
MVFR CONDITIONS THRU THIS MRNG WL GIVE WAY TO SOME IFR CONDITIONS AS
A LO PRES TROF DRIFTS THRU THE AREA. A BIT STRONGER NW UPSLOPE FLOW
FOLLOWING THIS TROF WL CAUSE IFR CONDITIONS TO PERSIST AT THESE
SITES THRU THE END OF THE FCST PERIOD AS SUFFICIENTLY COLD AIR FOR
LES ARRIVES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 344 AM EST WED JAN 21 2015
A WEAK SURFACE TROUGH OVER WESTERN LAKE SUPERIOR WILL SLOWLY DROP
SOUTHEAST TODAY...WHICH WILL SHIFT WINDS TO THE NORTHWEST UP TO
20KTS. A HIGH PRESSURE RIDGE WILL MOVE ACROSS THE UPPER GREAT LAKES
REGION TONIGHT AND THURSDAY MORNING...LEADING TO WINDS GRADUALLY
BACKING. WINDS WILL BACK TO THE SOUTHWEST THURSDAY AFTERNOON AND
INCREASE AHEAD OF A LOW PRESSURE SYSTEM MOVING SOUTHEAST THROUGH
CENTRAL CANADA. THIS WILL LEAD TO THE POTENTIAL FOR SOUTHWESTERLY
GALE FORCE GUSTS TO 35KTS OVER WESTERN AND CENTRAL LAKE SUPERIOR
THURSDAY NIGHT INTO FRIDAY MORNING. A GALE WATCH HAS BEEN ISSUED
FOR THAT PERIOD. A COLD FRONT WILL DROP ACROSS LAKE SUPERIOR FRIDAY
AFTERNOON AND EVENING...SHIFTING WINDS TO THE NORTHWEST UP TO 30KTS
FOR SATURDAY. AN AREA OF HIGH PRESSURE MOVING OVER NORTHERN ONTARIO
ON SATURDAY WILL LEAD TO WEAKENING AND VEERING WINDS SATURDAY NIGHT.
A LOW PRESSURE SYSTEM MOVING SOUTHEAST ACROSS MINNESOTA AND NORTHERN
ILLINOIS LATE SATURDAY NIGHT AND SUNDAY WILL DRAG A TROUGH ACROSS
LAKE SUPERIOR SUNDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING FOR
LSZ263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLB
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
345 AM EST WED JAN 21 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 344 AM EST WED JAN 21 2015
UPPER MICHIGAN IS BETWEEN TWO SHORTWAVES EARLY THIS MORNING...WITH
ONE MOVING THROUGH SOUTHERN MINNESOTA AND NORTHEAST IOWA AND THE
OTHER ACROSS NORTHERN ONTARIO. THIS LEAVES THE CWA UNDER GENERALLY
QUIET CONDITIONS WITH THE FORECAST DEPENDENT ON SMALLER SCALE
FEATURES.
THE AREA OF LOW CLOUDS THAT ERODED OVER EASTERN AND CENTRAL UPPER
MICHIGAN YESTERDAY UNDER THE LIGHT NORTHEAST ASSOCIATED WITH A HIGH
PRESSURE RIDGE HAS BEEN SLOWLY MOVING EAST ACROSS CENTRAL UPPER
MICHIGAN AS 950-925MB WINDS ARE OUT OF THE WEST ON THE RAP ANALYSIS.
WITH WINDS ONLY AROUND 5KTS...THIS EASTWARD PROGRESSION WILL BE SLOW
THROUGH THE MORNING AND LIKELY OVERTAKEN THIS AFTERNOON BY THE WINDS
SHIFTING NORTHWEST OFF LAKE SUPERIOR BEHIND A SURFACE TROUGH. WHERE
SKIES HAVE BEEN CLEAR THIS MORNING...TEMPERATURES HAVE FALLEN INTO
THE SINGLE DIGITS BELOW ZERO OVER EASTERN UPPER MICHIGAN. BUT OVER
THE WESTERN U.P. WITH THE ABUNDANT LOW CLOUDS...TEMPERATURES ARE IN
THE UPPER TEENS TO LOWER 20S. AS CLOUDS MOVED OVERHEAD HERE AT THE
OFFICE...TEMPERATURES ROSE FROM -1F AT MIDNIGHT TO 12F AT 330AM.
THE WEAK SURFACE TROUGH CURRENTLY OVER WESTERN LAKE SUPERIOR WILL BE
THE MAIN CONTROLLING FACTOR FOR THE FORECAST TODAY. AS THIS TROUGH
SLOWLY SLIDES SOUTHEAST ACROSS THE AREA...THINK THERE WILL BE SOME
SNOW SHOWERS ASSOCIATED WITH THE SURFACE TROUGH THIS MORNING OVER
THE KEWEENAW AND THEN THAT WILL SHIFT SOUTHEAST ACROSS THE REST OF
WESTERN AND CENTRAL UPPER MICHIGAN THIS AFTERNOON/EVENING. WILL SHOW
ISOLATED/SCATTERED SNOW SHOWERS ALONG THE TROUGH AS IT MOVES THROUGH
THOSE AREAS. BEHIND THE TROUGH...WINDS WILL SHIFT TO THE NORTHWEST
AND THE LOW LEVEL THERMAL PROFILE WILL GRADUALLY COOL...LEADING TO
MORE FAVORABLE LAKE EFFECT CONDITIONS ON THE NW WIND SNOWBELTS.
DELTA-T VALUES ARE ONLY AROUND 13...WHICH IS ON THE LOW END FOR LAKE
EFFECT...AND WITH LOW LEVEL LAPSE RATES BEING FAIRLY WEAK (1000-
850MB LAPSE RATES AROUND 6-7C/KM)...WOULD NOT EXPECT THE LAKE EFFECT
TO GET TOO OUT OF HAND. DO GET A LITTLE HELP ALONG AND SHORTLY AFTER
THE TROUGH WITH SOME DEEPER MOISTURE. BUT THAT REALLY DIMINISHES
THROUGH THE NIGHT AS A SURFACE RIDGE NOSES INTO THE
AREA...STRENGTHENING THE SUBSIDENCE INVERSION (LOWERS TO 4-4.5KFT)
AND GRADUALLY BACKS WINDS TO THE WEST BY 12Z THURSDAY. THE AREA DOES
GET BRUSHED BY A SHORTWAVE MOVING THROUGH NORTHERN ONTARIO TONIGHT.
THIS SWEEPS A POCKET OF COLDER 850MB TEMPS (TO
-12C) SOUTHEAST ACROSS CENTRAL/EASTERN LAKE SUPERIOR DURING THE
NIGHT AND INCREASES THE LOW LEVEL WINDS SOME. WILL INCREASE THE POPS
OVER THE EAST AS THAT MOVES THROUGH...BUT STILL KEEP IN THE CHANCE
CATEGORY.
SNOW RATIOS SHOULD BE SIGNIFICANTLY LOWER THAN SEEN A COUPLE DAYS
AGO WITH ONLY TO TOP 1KFT OF THE CLOUD IN THE BOTTOM OF THE DGZ. THE
WINDS WILL BE LIGHT...WHICH WILL HELP KEEP THE FRACTURING DOWN...BUT
WITH MUCH OF THE FORCING BELOW THE DGZ WOULD EXPECT SNOW RATIOS
AROUND THE MID TEENS. THEREFORE THROUGH TONIGHT...HAVE SNOWFALL
AMOUNTS IN THE NW WIND SNOW BELTS OF A DUSTING TO AN INCH WITH A FEW
ISOLATED AMOUNTS HIGHER THAN THAT.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 435 PM EST TUE JAN 20 2015
A TROUGH OF LOW PRESSURE WILL REMAIN ACROSS EASTERN CANADA AND MUCH
OF THE EASTERN U.S. THROUGH THE PERIOD...WITH A RIDGE ACROSS THE FAR
W. AS A RESULT...A SERIES OF WAVES WILL DIVE S ACROSS THE UPPER
GREAT LAKES REGION. HIGH TEMPERATURES WILL GENERALLY HOVER IN THE
20S TO LOW 30S...WHICH IS NEAR TO JUST SLIGHTLY ABOVE NORMAL FOR MID
TO LATE JANUARY.
TO BEGIN 00Z THURSDAY NW FLOW OVER THE W HALF AND 850MB TEMPS NEAR -
12C...WITH SOME MOISTURE IN THE DGZ WILL BE OPPOSED TO THE
STRENGTHENING INVERSION. EXPECT ONLY LIGHT SNOW. UPPER MI WILL BE IN
BETWEEN A WAVE SLIDING TO OUR S...AND AN ADDITIONAL WAVE STRETCHING
FROM THE 500MB TROUGH AND ASSOCIATED SFC LOW OVER HUDSON BAY
STRETCHING ACROSS ONTARIO. WHILE COOLER AIR WILL BRIEFLY SLIDE IN
WEDNESDAY NIGHT...MOISTURE WILL BE LIMITED AS HIGH PRESSURE SLOWLY
BUILDS IN.
STRENGTHENING WINDS WILL BE THE MAIN STORY FOR THURSDAY NIGHT INTO
FRIDAY...AS UPPER MI RESIDES BETWEEN THE STRONG LOW SETTLING ACROSS
THE OHIO VALLEY AND A ORGANIZED LOW ACROSS N MANITOBA AT 00Z FRIDAY.
EXPECT THE LOW TO SHIFT TO CROSS N AND CENTRAL ONTARIO FRIDAY...AND
EXIT ACROSS JAMES BAY FRIDAY EVENING. HIGHS IN THE LOW TO MID 30S
/AROUND 10F ABOVE NORMAL/ LOOK REASONABLE FOR FRIDAY AFTERNOON AS
850MB TEMPS RISE TO 0 TO 3C...ALONG WITH A CHANCE OF SNOW AND PATCHY
BLOWING SNOW ALONG LAKE SUPERIOR. THE MAIN SFC TROUGH WILL USHER
COOLER AIR BACK INTO THE CWA SATURDAY...WITH SLOWLY FALLING TEMPS
THROUGH THE DAY. DECREASED WINDS SLIGHTLY FROM WHAT WE HAD
ORIGINALLY FRIDAY NIGHT/SATURDAY...WHICH WILL NEED TO BE MONITORED.
THURSDAY NIGHT/FRIDAY MORNING STILL LOOKS TO BE THE PERIOD OF
STRONGEST WINDS. THE 20/12Z ECMWF HAS COME IN WITH 40-50KT W WINDS
AT 850MB 06-12Z FRIDAY.
LOOKING FARTHER OUT...THERE ARE SOME SIGNIFICANT DISCREPANCIES AS WE
MOVE INTO THE LONGER RANGE OF THIS FCST...FROM MONDAY AFTERNOON ON.
ONE CHANGE FOR THIS ISSUANCE WAS TO LIMIT THE TIME OF N-NE WINDS
ACROSS LAKE SUPERIOR...BRINING LIGHT TO MODERATE LES INTO N CENTRAL
UPPER MI. THE 02/12Z ECMWF STILL HOLDS ONTO THE EXTENDED DURATION OF
COOL N-NE WINDS...WITH 850MB TEMPS AROUND -15C. THE GFS SWEEPS A LOW
ACROSS THE AREA...WITH VARIED WIND DIRECTIONS. WILL CONTINUE A BLEND
AT THIS TIME...AND WAIT FOR FCST MODELS TO HAVE A BETTER HANDLE ON
THIS LATER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1226 AM EST WED JAN 21 2015
EXPECT MOCLR SKIES/VFR CONDITIONS AT SAW EARLY IN THE TAF PERIOD
WITH LINGERING LLVL DRY AIR TO GIVE WAY TO MORE CLDS/MVFR CONDITIONS
AS THE FLOW JUST ABOVE THE SFC SHIFTS TO A NW DIRECTION THAT WL DRAG
MORE SC TO DRIFT BACK INTO THE AREA. AT CMX AND IWD...PREDOMINANT
MVFR CONDITIONS THRU THIS MRNG WL GIVE WAY TO SOME IFR CONDITIONS AS
A LO PRES TROF DRIFTS THRU THE AREA. A BIT STRONGER NW UPSLOPE FLOW
FOLLOWING THIS TROF WL CAUSE IFR CONDITIONS TO PERSIST AT THESE
SITES THRU THE END OF THE FCST PERIOD AS SUFFICIENTLY COLD AIR FOR
LES ARRIVES.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 344 AM EST WED JAN 21 2015
A WEAK SURFACE TROUGH OVER WESTERN LAKE SUPERIOR WILL SLOWLY DROP
SOUTHEAST TODAY...WHICH WILL SHIFT WINDS TO THE NORTHWEST UP TO
20KTS. A HIGH PRESSURE RIDGE WILL MOVE ACROSS THE UPPER GREAT LAKES
REGION TONIGHT AND THURSDAY MORNING...LEADING TO WINDS GRADUALLY
BACKING. WINDS WILL BACK TO THE SOUTHWEST THURSDAY AFTERNOON AND
INCREASE AHEAD OF A LOW PRESSURE SYSTEM MOVING SOUTHEAST THROUGH
CENTRAL CANADA. THIS WILL LEAD TO THE POTENTIAL FOR SOUTHWESTERLY
GALE FORCE GUSTS TO 35KTS OVER WESTERN AND CENTRAL LAKE SUPERIOR
THURSDAY NIGHT INTO FRIDAY MORNING. A GALE WATCH HAS BEEN ISSUED
FOR THAT PERIOD. A COLD FRONT WILL DROP ACROSS LAKE SUPERIOR FRIDAY
AFTERNOON AND EVENING...SHIFTING WINDS TO THE NORTHWEST UP TO 30KTS
FOR SATURDAY. AN AREA OF HIGH PRESSURE MOVING OVER NORTHERN ONTARIO
ON SATURDAY WILL LEAD TO WEAKENING AND VEERING WINDS SATURDAY NIGHT.
A LOW PRESSURE SYSTEM MOVING SOUTHEAST ACROSS MINNESOTA AND NORTHERN
ILLINOIS LATE SATURDAY NIGHT AND SUNDAY WILL DRAG A TROUGH ACROSS
LAKE SUPERIOR SUNDAY NIGHT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM THURSDAY EVENING THROUGH FRIDAY MORNING FOR
LSZ263-264.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...KF
AVIATION...KC
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1227 AM EST WED JAN 21 2015
.UPDATE...
ISSUED AT 535 PM EST TUE JAN 20 2015
LATEST STLT IMAGERY INDICATES LK INDUCED VORTEX E OF THE KEWEENAW IS
TENDING TO TURN MORE TO THE NNE AND AWAY FM THE KEWEENAW PENINSULA.
THIS MOTION IS IN LINE WITH THE LLVL SSW FLOW THIS MESOVORTEX IS
ENCOUNTERING ON THE NRN FLANK OF SFC RDG AXIS ORIENTED E-W ACROSS
UPR MI. OPTED TO LOWER POPS OVER THE KEWEENAW FOR THIS EVNG BASED ON
THIS CHANGE IN TRACK.
CONSIDERING THE DRYNESS OF THE AIRMASS IN PLACE...WITH PWAT IN THE
0.10 TO 0.15 RANGE...OPTED TO LOWER FCST MIN TEMPS OVER THE ERN CWA
WHERE SKIES ARE LIKELY TO REMAIN MOCLR AND WINDS LGT THRU THE NGT.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 416 PM EST TUE JAN 20 2015
WATER VAPOR LOOP AND RUC ANALYSIS INDICATES A NW FLOW OVER THE
REGION AS THE MAIN SHORTWAVE EMBEDDED IN THIS FLOW IS WELL SW OF THE
UPPER LAKES. VIS SATELLITE LOOP SHOWS LOW CLOUDS PERSISTING OVER THE
W-SW FCST AREA WITH MOSTLY SUNNY SKIES ACROSS THE NCNTRL AND ERN
FCST AREA. MESOSCALE LOW IS EVIDENT JUST EAST OF THE KEWEENAW AND
MOVING SLOWLY EAST.
TONIGHT...LATEST HIGH RES MODELS HAVING A POOR TIME RESOLVING
MESOSCALE FEATURE EAST OF THE KEWEENAW THIS EVENING. AS A
RESULT...HAD TO ADJUST POPS UP TO 50-60 PCT OVER THE TIP OF
THE KEWEENAW AT LEAST THROUGH THIS EVENING TO ACCOUNT FOR THE LES
POTENTIAL. ALSO BUMPED UP SNOW ACCUMULATION TO 1-2 INCHES OVER
THE TIP OF THE KEWEENAW THROUGH THIS EVENING BUT THIS MAY BE TOO
CONSERVATIVE GIVEN FAIRLY IMPRESSIVE LOOK TO THE MESOLOW ON VISIBLE
SATELLITE.
ELSEWHERE TONIGHT TEMPS AND CLOUDS WILL BE THE MAIN CONCERN AND
DETERMINING HOW FAR WEST THE CLEARING LINE REACHES INTO SW UPPER MI
THIS EVENING. THIS WILL HAVE A BIG IMPACT ON MIN TEMPS. AT A
MININUM...WHERE THERE IS CLEARING...SHOULD SEE TEMPS LOWERING INTO
AT LEAST THE SINGLE DIGITS BLO ZERO AND PROBABLY WILL REACH COLDER
THAN -10F AT SOME OF THE COLDER EASTERN INTERIOR LOCATIONS. WILL
KEEP TEMPS CLOSER TO 10-12F OVER THE FAR WEST WHERE CLOUDS SHOULD
PERSIST THROUGH THE NIGHT.
WEDNESDAY...WEAK SHORTWAVE MOVING DOWN FROM MANITOBA/NRN ONTARIO
WILL PUSH A SURFACE TROUGH INTO NW UPPER MI/SCNTRL LAKE SUPERIOR.
LOOK FOR THIS TROUGH TO BECOME THE FOCUS FOR SOME LIGHT LES AS 850
MB TEMPS LINGER AROUND -11C. WILL MAINTAIN SLIGHT CHC TO LOW CHC
POPS OVER NW AND NCNTRL ZONES. EXPECT TEMPS TO REBOUND FM CHILLY
OVERNIGHT LOWS AND REACH INTO THE LOWER 20S EAST TO MID TO UPPER 20S
WEST AND CENTRAL.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 435 PM EST TUE JAN 20 2015
A TROUGH OF LOW PRESSURE WILL REMAIN ACROSS EASTERN CANADA AND MUCH
OF THE EASTERN U.S. THROUGH THE PERIOD...WITH A RIDGE ACROSS THE FAR
W. AS A RESULT...A SERIES OF WAVES WILL DIVE S ACROSS THE UPPER
GREAT LAKES REGION. HIGH TEMPERATURES WILL GENERALLY HOVER IN THE
20S TO LOW 30S...WHICH IS NEAR TO JUST SLIGHTLY ABOVE NORMAL FOR MID
TO LATE JANUARY.
TO BEGIN 00Z THURSDAY NW FLOW OVER THE W HALF AND 850MB TEMPS NEAR -
12C...WITH SOME MOISTURE IN THE DGZ WILL BE OPPOSED TO THE
STRENGTHENING INVERSION. EXPECT ONLY LIGHT SNOW. UPPER MI WILL BE IN
BETWEEN A WAVE SLIDING TO OUR S...AND AN ADDITIONAL WAVE STRETCHING
FROM THE 500MB TROUGH AND ASSOCIATED SFC LOW OVER HUDSON BAY
STRETCHING ACROSS ONTARIO. WHILE COOLER AIR WILL BRIEFLY SLIDE IN
WEDNESDAY NIGHT...MOISTURE WILL BE LIMITED AS HIGH PRESSURE SLOWLY
BUILDS IN.
STRENGTHENING WINDS WILL BE THE MAIN STORY FOR THURSDAY NIGHT INTO
FRIDAY...AS UPPER MI RESIDES BETWEEN THE STRONG LOW SETTLING ACROSS
THE OHIO VALLEY AND A ORGANIZED LOW ACROSS N MANITOBA AT 00Z FRIDAY.
EXPECT THE LOW TO SHIFT TO CROSS N AND CENTRAL ONTARIO FRIDAY...AND
EXIT ACROSS JAMES BAY FRIDAY EVENING. HIGHS IN THE LOW TO MID 30S
/AROUND 10F ABOVE NORMAL/ LOOK REASONABLE FOR FRIDAY AFTERNOON AS
850MB TEMPS RISE TO 0 TO 3C...ALONG WITH A CHANCE OF SNOW AND PATCHY
BLOWING SNOW ALONG LAKE SUPERIOR. THE MAIN SFC TROUGH WILL USHER
COOLER AIR BACK INTO THE CWA SATURDAY...WITH SLOWLY FALLING TEMPS
THROUGH THE DAY. DECREASED WINDS SLIGHTLY FROM WHAT WE HAD
ORIGINALLY FRIDAY NIGHT/SATURDAY...WHICH WILL NEED TO BE MONITORED.
THURSDAY NIGHT/FRIDAY MORNING STILL LOOKS TO BE THE PERIOD OF
STRONGEST WINDS. THE 20/12Z ECMWF HAS COME IN WITH 40-50KT W WINDS
AT 850MB 06-12Z FRIDAY.
LOOKING FARTHER OUT...THERE ARE SOME SIGNIFICANT DISCREPANCIES AS WE
MOVE INTO THE LONGER RANGE OF THIS FCST...FROM MONDAY AFTERNOON ON.
ONE CHANGE FOR THIS ISSUANCE WAS TO LIMIT THE TIME OF N-NE WINDS
ACROSS LAKE SUPERIOR...BRINING LIGHT TO MODERATE LES INTO N CENTRAL
UPPER MI. THE 02/12Z ECMWF STILL HOLDS ONTO THE EXTENDED DURATION OF
COOL N-NE WINDS...WITH 850MB TEMPS AROUND -15C. THE GFS SWEEPS A LOW
ACROSS THE AREA...WITH VARIED WIND DIRECTIONS. WILL CONTINUE A BLEND
AT THIS TIME...AND WAIT FOR FCST MODELS TO HAVE A BETTER HANDLE ON
THIS LATER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1226 AM EST WED JAN 21 2015
EXPECT MOCLR SKIES/VFR CONDITIONS AT SAW EARLY IN THE TAF PERIOD
WITH LINGERING LLVL DRY AIR TO GIVE WAY TO MORE CLDS/MVFR CONDITIONS
AS THE FLOW JUST ABOVE THE SFC SHIFTS TO A NW DIRECTION THAT WL DRAG
MORE SC TO DRIFT BACK INTO THE AREA. AT CMX AND IWD...PREDOMINANT
MVFR CONDITIONS THRU THIS MRNG WL GIVE WAY TO SOME IFR CONDITIONS AS
A LO PRES TROF DRIFTS THRU THE AREA. A BIT STRONGER NW UPSLOPE FLOW
FOLLOWING THIS TROF WL CAUSE IFR CONDITIONS TO PERSIST AT THESE
SITES THRU THE END OF THE FCST PERIOD AS SUFFICIENTLY COLD AIR FOR
LES ARRIVES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 416 PM EST TUE JAN 20 2015
A RELATIVELY TRANQUIL PERIOD IS EXPECTED INTO THURSDAY WITH WINDS
BELOW 30 KNOTS. HOWEVER...SW WINDS WILL INCREASE TO 30 KNOTS THU
NIGHT WITH A FEW GALE FORCE GUSTS POSSIBLE AS LOW PRESSURE MOVES
TOWARD JAMES BAY. WEST WINDS TO 30 KNOTS ARE EXPECTED TO CONTINUE
FRI INTO SAT AS WINDS VEER TO THE WEST AND THEN TO THE NORTHWEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...KC
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
354 PM CST WED JAN 21 2015
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 308 PM CST WED JAN 21 2015
WATER VAPOR IMAGERY OVERLAID WITH A RAP H5 ANALYSIS THIS AFTERNOON
SHOWS A RATHER ACTIVE PATTERN. THE RIDGE ON THE WEST COAST IS
AMPLIFYING...WITH A BROAD TROUGH ACROSS MOST OF NOAM EAST OF THE
ROCKIES. WITHIN THIS THROUGH...THE MOST PROMINENT FEATURE IS THE
WAVE MOVING THROUGH THE 4 CORNERS REGION...BUT THIS WILL REMAIN WELL
SOUTH OF US. CLOSER TO HOME THE SHORTWAVE THAT BROUGHT THE SNOW IN
YESTERDAY IS NOW OFF OVER SRN MICHIGAN. THE PV WITH THIS WAVE
EXTENDS BACK TO THE WEST INTO A TROUGH WITH ITS BASE IN WYOMING.
WITHIN THIS...YOU WILL FIND YET ANOTHER EMBEDDED SHORTWAVE SLOWLY
MOVING SOUTH THROUGH SODAK. AS WE GO THROUGH TONIGHT THIS BAGGY
THROUGH WILL SAG SOUTH OF US...WITH SHORTWAVE RIDGING TAKING ITS
PLACE FOR THURSDAY. UNTIL THIS GENERAL TROUGHINESS CLEARS THE
AREA...WE WILL MAINTAIN THE CLOUDS WITH OCCASIONAL LIGHT
SNOW/FLURRIES...THOUGH NO ADDITIONAL ACCUMULATIONS ARE EXPECTED.
THE BIG QUESTION FOR THE SHORT TERM IS WHEN EXACTLY WILL THESE
CLOUDS CLEAR OUT. ON THE HEELS OF THE UPPER WAVE MOVING OUT WILL A
SFC RIDGE MOVING IN. THE SUBSIDENCE AND DRYING WITH THIS WILL HELP
CLEAR OUT THE CLOUDS. BELIEVE THE NAM BUFR SOUNDINGS ARE TOO MOIST
IN THE LOW LEVELS...SO FOLLOWED MORE OF A GFS IDEA WITH SKIES
CLEARING FROM N TO S TONIGHT....THOUGH WENT A BIT SLOWER THAN THE
NAM GIVEN THE HRRRS DEPICTION OF HOW THE STRATUS SHIELD WILL CLEAR
OUT THIS EVENING. WE WILL SOME CLEAR SKIES ON THURSDAY BEFORE
MID/HIGH CLOUDS INCREASE AGAIN ACROSS CENTRAL MN DURING THE
AFTERNOON IN RESPONSE TO A SHORTWAVE MOVING ACROSS SRN CANADA.
TEMPERATURES WILL BE THE TRICKIEST PART OF THE FORECAST AS THEY WILL
BE HIGHLY DEPENDENT ON CLOUD COVER. FOR PLACES THAT KEEP THE
CLOUDS...LOWS WILL STAY IN THE 20S. YOU LOSE YOUR CLOUDS...WELL WITH
LIGHT WINDS TEMP DROPS WILL BE OFF TO THE RACES...LIKELY SETTLING IN
THE SINGLE DIGITS IF ENOUGH TIME WITH CLEAR SKIES CAN HAPPEN. THIS
WOULD BE MOST LIKELY FOR CENTRAL MN. FOR THURSDAY...SW WINDS WILL BE
INCREASING THROUGH THE DAY. THIS WILL QUICKLY PUT AN END TO THE WEAK
CAA WE ARE SEEING THIS AFTERNOON...WITH HIGHS BACK IN THE 30S LIKELY
OUT IN THE MN RIVER VALLEY...WITH WARMER TEMPS STILL TO COME.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 308 PM CST WED JAN 21 2015
A CLIPPER SYSTEM WILL BE SLIDING EAST THROUGH THE SOUTHERN
CANADIAN PROVINCES BY THURSDAY NIGHT...BUT ESSENTIALLY ALL PRECIP
WILL STAY NORTH OF THE INTERNATIONAL BORDER. THE MAIN CONCERN FOR
OUR AREA IS WHETHER OR NOT ANY PRECIP WILL BE PRODUCED ALONG THE
COLD FRONTAL BOUNDARY ASSOCIATED WITH THIS SYSTEM THAT IS SET TO
DROP SOUTH THROUGH OUR AREA ON FRIDAY. MODELS GENERALLY AGREE ON
SQUEEZING OUT LIGHT PRECIP ALONG THIS FRONTAL BOUNDARY. THERMAL
PROFILES REMAIN WARM...SO ANY LIGHT PRECIP THAT DOES FALL WILL BE
A MIX OF SNOW...SLEET...AND RAIN.
THE OVERALL PATTERN IN THE LONG RANGE WILL CONSIST OF AN UPPER
RIDGE ACROSS WESTERN NORTH AMERICA AND A TROUGH ACROSS EASTERN
NORTH AMERICA. YET ANOTHER CLIPPER WILL DIVE SOUTHEAST THROUGH
CANADA THIS WEEKEND...BUT THIS SYSTEM LOOKS STRONGER AND THE
SHORTWAVE WILL AMPLIFY AS IT APPROACHES THE NORTHERN STATES. THE
LATEST GFS RUN INDICATES A SLIGHT SHIFT TO THE EAST WHICH WOULD
PUT WESTERN WI AND EXTREME EASTERN MN UNDER THE HEAVIEST
POTENTIAL...WHICH REMAINS AT ABOUT 0.20-0.30" OF LIQUID QPF. IN
THIS AREA...THERMAL PROFILES ARE INDICATIVE OF ALL SNOW HERE SO A
COUPLE OF INCHES OF ACCUMULATION REMAINS A POSSIBILITY.
HOWEVER...THIS SYSTEM IS STILL 3.5-4 DAYS AWAY SO MUCH CAN
CHANGE. ESPECIALLY BECAUSE THERE IS DECENT POTENTIAL FOR A STRONG
NOR`EASTER TO MOVE UP THE EAST COAST. THIS FEATURE WILL PLAY A
KEY PART IN THE EVOLUTION OF UPSTREAM FEATURES SO SHIFTS IN OUR
CLIPPER ARE CERTAINLY POSSIBLE.
AS WE HEAD INTO NEXT WEEK...THE WESTERN RIDGE WILL BASICALLY HOLD
FIRM AND THE ECMWF INDICATES ANOTHER LIGHT SNOWFALL EVENT POSSIBLE
FOR OUR AREA. THERE IS NOT MUCH AGREEMENT WITH THIS SYSTEM
HOWEVER...AS THE GFS IS MUCH STRONGER AND NORTHEAST OF OUR AREA
WITH THE MAIN PRECIP.
TEMPERATURES LOOK TO REMAIN ABOVE NORMAL THROUGH EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1144 AM CST WED JAN 21 2015
MAIN ISSUE THIS TAF PERIOD WAS WHEN TO BRING THROUGH CLEARING
TONIGHT/THU MORNING. BELIEVE THE NAM IS WAY TO OVERDONE ON LOW
LEVEL MOISTURE AND BELIEVE AS THE SFC RIDGE WORKS THROUGH...IT
WILL BRING CLEARING SKIES WITH IT. FOR TIMING...THE HRRR SUGGESTS
THAT THE GFSLAMP IS A BIT TOO AGGRESSIVE WITH ITS CLEARING...SO
WENT SLOWER WITH CIG IMPROVEMENTS THAN WHAT THE LAMP HAS. BASED
ON OBS UPSTREAM...CONDS WILL LIKELY DETERIORATE AS SITES GET INTO
THE BACK EDGE OF THE STRATUS...SO TRENDED TAFS BACK TO IFR/LOW END
MVFR BEFORE CLEARING THEM OUT. ALTHOUGH NO ACCUMULATIONS ARE
EXPECTED...EAU WILL SEE -SN CONTINUE FOR NO MORE THAN A COUPLE OF
HOURS...WHILE ANOTHER AREA OF SNOW IN WC MN MAY BRUSH RWF THIS
AFTERNOON.
KMSP...WE WILL BE MAINTAINING THE STRATUS...LIKELY THROUGH THE
WHOLE NIGHT. STILL SEE NO REASON WHY CIGS WILL NOT IMPROVE TO
ABOVE 017 THIS AFTERNOON...BUT THE LARGE BANK OF IFR CONDS ACROSS
NRN MN PUSHED ME TO BRINGING CIGS BACK UNDER 017 TONIGHT. WILL
HAVE TO WATCH TRENDS...BUT COULD SEE MSP DEALING WITH IFR CIGS
AGAIN THU MORNING. EXPECT STRATUS TO CLEAR OUT BY 15Z AT THE
LATEST...AND ONCE IT DOES ITS MAINLY CLEAR SKIES WITH SW WINDS
FOR THE REST OF THE TAF PERIOD.
/OUTLOOK FOR KMSP/
FRI...MVFR CIGS IN AFTN. WIND SW AT 10 KTS.
SAT...VFR. CHC IFR/MVFR -SN LATE. WINDS NW 5-10 KTS.
SUN...IFR/MVFR. CHC MORNING -SN. WINDS NE 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...SPD
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1201 PM CST WED JAN 21 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 349 AM CST WED JAN 21 2015
SNOW WILL GRADUALLY TAPER OFF TODAY AS SUBSIDENCE AND HIGH
PRESSURE BUILDS IN LATER TONIGHT. THIS WILL SET THE STAGE FOR
COLDER TEMPERATURES BY THURSDAY MORNING...ESPECIALLY IF SKIES
CLEAR OUT AS CURRENTLY FORECAST.
EARLY MORNING WATER VAPOR IMAGERY OVERLAID WITH 500MB HEIGHTS AND
WINDS IDENTIFIED TWO AREAS OF ENHANCED VORTICITY. THE FIRST WAS
CENTERED OVER THE MN/WI/IA BORDER...AND WAS RESPONSIBLE FOR THE
LIGHT SNOW FROM YESTERDAY. THE SECOND IS AN OPEN AVE ACROSS THE
DAKOTAS...AND SHOULD ALLOW A FEW SNOW SHOWERS TO PERSIST ACROSS THE
SOUTHEAST PORTION OF THE FORECAST AREA...IN PARTICULAR THE MINNESOTA
RIVER VALLEY. HOWEVER...THIS AREA OF VORTICITY WILL WEAKEN AS IT
GETS STRUNG OUT BY THE SPEEDMAX TO THE SOUTH...WHILE AN UPPER LEVEL
RIDGE BREAK OVERHEAD.
500MB HEIGHT RISES WILL PROMOTE SUBSIDENCE AND SURFACE HIGH PRESSURE
ACROSS THE UPPER MIDWEST LATER TONIGHT...WHICH WILL BRING A FINITE
END TO THE LIGHT SNOW/FLURRIES. FORECAST SOUNDINGS DRY OUT
CONSIDERABLY...AND DEPENDING ON THE RESIDUAL BOUNDARY LAYER MOISTURE
SHOULD SEE CLEARING SKIES AFTER MIDNIGHT ACROSS THE NORTHWEST. THE
UNCERTAINTY IN THE TIMING/AMOUNT OF CLEARING YIELDS LITTLE
CONFIDENCE IN THE LOW TEMPERATURES...AS COULD SEE TEMPS DROP SEVERAL
DEGREES INTO THE SINGLE DIGITS BEFORE SUNRISE UNDER CLEAR...CALM
CONDITIONS. HOWEVER...WARM AIR ADVECTION WILL BE ON THE DOORSTEP
FROM UPSTREAM SUBSIDENCE/CHINOOK WINDS.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 349 AM CST WED JAN 21 2015
THE LONG TERM WILL FEATURE CONTINUED ABOVE NORMAL TEMPERATURES
ALONG WITH A DECENT CHANCE FOR A PLOWABLE SNOWFALL EVENT DURING
THE LAST HALF OF THE WEEKEND.
THE LARGE SCALE PATTERN WILL FEATURE UPPER RIDGING NOSING INTO THE
PACIFIC NORTHWEST...WHICH WILL BE CONDUCIVE TO A PARADE OF WEAK
RIDGE-TOPPING SHORTWAVES DIVING ACROSS THE CENTRAL CONUS DURING
THE PERIOD.
ONE SUCH WAVE SCRAPES THE EASTERN PART OF THE AREA ON FRIDAY.
MOISTURE AND FORCING SOURCES ARE LIMITED...SO HAVE ONLY INCLUDED A
20 POP. THE ONE UNFORTUNATE REALITY IS THAT THE MILD AIR IN PLACE
WILL MEAN THE PRECIP TYPE WOULD BE A MIX OF RAIN...SNOW...AND
POSSIBLY EVEN SLEET.
A MUCH STRONGER WAVE IS FORECAST TO CLIP THE REGION ON SATURDAY
NIGHT AND SUNDAY. THIS SYSTEM IS FORECAST TO BE ACCOMPANIED BY
STRONG PV ADVECTION...700-600MB FORCING AND DEEP MOISTURE. A
MODERATE BAND OF SNOWFALL STILL LOOKS TO BLOSSOM OVER THE FORECAST
AREA ON SATURDAY NIGHT AND SUNDAY. WHILE THE AMPLITUDE/SPATIAL
DETAILS ARE NOT ENTIRELY CERTAIN AT THIS POINT...IT STILL LOOKS
LIKE A SWATH OF 0.20 TO 0.30 QPF IS POSSIBLE OVER THE AREA...WHICH
WOULD TRANSLATE TO 2 TO 4 INCHES.
THE NEXT WAVE IS FORECAST TO TOP THE RIDGE ON TUESDAY AND DROP
ACROSS THE FORECAST AREA. IT PRIMARILY LOOKS TO CLIP THE EASTERN
FRINGES OF THE AREA...SO HAVE RESTRICTED THE 20 POPS TO WEST
CENTRAL WI.
HIGH TEMPERATURES THROUGH THE PERIOD PRIMARILY RANGE FROM THE
UPPER 20S TO UPPER 30S FOR HIGHS...AND THE MID TEENS TO MID 20S
FOR LOWS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1144 AM CST WED JAN 21 2015
MAIN ISSUE THIS TAF PERIOD WAS WHEN TO BRING THROUGH CLEARING
TONIGHT/THU MORNING. BELIEVE THE NAM IS WAY TO OVERDONE ON LOW
LEVEL MOISTURE AND BELIEVE AS THE SFC RIDGE WORKS THROUGH...IT
WILL BRING CLEARING SKIES WITH IT. FOR TIMING...THE HRRR SUGGESTS
THAT THE GFSLAMP IS A BIT TOO AGGRESSIVE WITH ITS CLEARING...SO
WENT SLOWER WITH CIG IMPROVEMENTS THAN WHAT THE LAMP HAS. BASED
ON OBS UPSTREAM...CONDS WILL LIKELY DETERIORATE AS SITES GET INTO
THE BACK EDGE OF THE STRATUS...SO TRENDED TAFS BACK TO IFR/LOW END
MVFR BEFORE CLEARING THEM OUT. ALTHOUGH NO ACCUMULATIONS ARE
EXPECTED...EAU WILL SEE -SN CONTINUE FOR NO MORE THAN A COUPLE OF
HOURS...WHILE ANOTHER AREA OF SNOW IN WC MN MAY BRUSH RWF THIS
AFTERNOON.
KMSP...WE WILL BE MAINTAINING THE STRATUS...LIKELY THROUGH THE
WHOLE NIGHT. STILL SEE NO REASON WHY CIGS WILL NOT IMPROVE TO
ABOVE 017 THIS AFTERNOON...BUT THE LARGE BANK OF IFR CONDS ACROSS
NRN MN PUSHED ME TO BRINGING CIGS BACK UNDER 017 TONIGHT. WILL
HAVE TO WATCH TRENDS...BUT COULD SEE MSP DEALING WITH IFR CIGS
AGAIN THU MORNING. EXPECT STRATUS TO CLEAR OUT BY 15Z AT THE
LATEST...AND ONCE IT DOES ITS MAINLY CLEAR SKIES WITH SW WINDS
FOR THE REST OF THE TAF PERIOD.
/OUTLOOK FOR KMSP/
FRI...MVFR CIGS IN AFTN. WIND SW AT 10 KTS.
SAT...VFR. CHC IFR/MVFR -SN LATE. WINDS NW 5-10 KTS.
SUN...IFR/MVFR. CHC MORNING -SN. WINDS NE 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JRB
LONG TERM...LS
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
958 PM CST THU JAN 22 2015
.UPDATE...
ISSUED AT 957 PM CST THU JAN 22 2015
QUICK UPDATE FOR POPS BASED ON CURRENT RADAR...KEPT A LITTLE
HIGHER POPS NORTH CENTRAL THROUGH THE EVENING AND INTO THE EARLY
OVERNIGHT HOURS. LATEST RAP SHOWS PRECIP HOLDING ON THROUGH AROUND
06-07 UTC WHICH AGREES WITH CURRENT FORECAST. LATEST HRRR HOLDS
PRECIP TOGETHER A LITTLE LONGER AND DROPS IT FARTHER SOUTH. IF
THIS WOULD HOLD TRUE AND PRECIP DOES NOT EVAPORATE...WE COULD SEE
A FEW FREEZING SPRINKLES OR LIGHT FREEZING RAIN AS REFLECTIVITIES
DROP SOUTH TOWARD GARRISON...HARVEY AND CARRINGTON. THATS A BIG
IF...AND WOULD STILL BE TALKING ABOUT ONLY TRACE AMOUNTS. WILL
KEEP ANY ACCUMULATING PRECIP CONFINED TO THE NORTH CENTRAL FOR NOW
AND PASS ALONG TO THE OVERNIGHT SHIFT.
UPDATE ISSUED AT 842 PM CST THU JAN 22 2015
SHOWERS HAVE INTENSIFIED ACROSS SOUTHWEST MB INTO NORTH CENTRAL
NORTH DAKOTA THIS EVENING AND HAVE BUMPED UP POPS FROM AROUND
SHERWOOD EAST THROUGH BOTTINEAU AND THE TURTLE MOUNTAINS TO
BELCOURT. QUITE A BIT OF DRY AIR BELOW THE PRECIPITATION AND
QUICK MOVEMENT WILL LIKELY YIELD MAINLY TRACE AMOUNTS. A FEW AREAS
COULD SEE A HUNDREDTH OR TWO. WARM FRONT HAS PUSHED INTO NORTHEAST
NORTH DAKOTA THUS TEMPERATURES ARE MAINLY IN THE MID 30S...AND
SHOULD REMAIN STEADY WITH A MODERATE WEST TO SOUTHWEST SURFACE
FLOW. AT THIS TIME IT LOOKS LIKE MAINLY SPRINKLES/RAIN SHOWERS.
WITH A SMALL PROBABILITY OF SOME LIGHT FREEZING RAIN AROUND
MIDNIGHT...BEFORE PRECIP TAPERS OFF AND MOVES EAST.
UPDATE ISSUED AT 605 PM CST THU JAN 22 2015
NO SIGNIFICANT UPDATES TO THE EARLY EVENING FORECAST. SURFACE LOW
TRACKING EAST ACROSS SOUTHERN CANADA. VERY LIGHT PRECIPITATION
EXTENDING FROM BRANDON SOUTHWEST TO WEYBURN AND JUST CLIPPING THE
INTERNATIONAL BORDER FROM CROSBY TO SHERWOOD. CURRENT TEMPERATURES
ARE ABOVE FREEZING AND EXPECTED PRECIPITATION WILL BE MAINLY TRACE
AMOUNTS. AT THIS TIME NO SIGNIFICANT HAZARDS EXPECTED...BUT WILL
MAINTAIN A SLIGHT CHANCE OF A MIX OF RAIN...SNOW AND FREEZING RAIN
ACROSS THE FAR NORTH EARLY THIS EVENING AND THEN DROPPING
SOUTHEAST INTO THE JAMES RIVER VALLEY LATER TONIGHT. UPDATED TEXT
PRODUCTS OUT SHORTLY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 310 PM CST THU JAN 22 2015
CURRENT SURFACE ANALYSIS PLACES LOW PUSHING THROUGH NORTHERN
MANITOBA WITH HIGH OVER THE GREAT BASIN. UPPER LEVEL ANALYSIS
PLACES RIDGE OVER THE WESTERN CONUS WITH A WEAK SHORTWAVE MOVING
THROUGH SOUTHERN SASKATCHEWAN INTO CENTRAL MONTANA. A FEW LIGHT
SHOWERS HAVE DEVELOPED OVER SOUTHERN SASKATCHEWAN/MANITOBA WITH
THIS SYSTEM.
FOR TONIGHT...AFOREMENTIONED SHORT WAVE MOVES THROUGH THE AREA
WHICH WILL BRING PRECIPITATION CHANCES MAINLY TO NORTHERN INTO
CENTRAL NORTH DAKOTA...THOUGH THE WAVE IS QUITE WEAK SO WILL LEAVE
CHANCES ON THE LOW SIDE. SOUNDING ANALYSIS SUGGESTS MAINLY RAIN
WITH THIS SYSTEM...WHICH COULD LEAD TO SOME FREEZING RAIN IF IT IS
PRECIPITATING WHEN TEMPS DROP BELOW FREEZING. SKIES WILL START
CLEARING IN THE WAKE OF THE WAVE AS IT PASSES THROUGH LATE TONIGHT.
ON FRIDAY...QUIET WEATHER IS EXPECTED AS UPPER RIDGE TO THE WEST
CONTINUES TO BE THE DOMINATE FEATURE AND REGION IS BETWEEN SYSTEM.
TEMPERATURES WILL REMAIN QUITE MILD.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 352 PM CST THU JAN 22 2015
ABOVE NORMAL TEMPERATURES AND SLIGHT CHANCES RAIN...FREEZING RAIN
AND SNOW HIGHLIGHT THE EXTENDED FORECAST.
AN UPPER LEVEL RIDGE ACROSS THE WEST COAST WILL REMAIN IN PLACE
THROUGH EARLY NEXT WEEK. THIS WILL KEEP THE MAJORITY OF THE ARCTIC
AIR BOTTLED UP AROUND THE HUDSON BAY. FOR OUR AREA TEMPERATURES
WILL GENERALLY RANGE FROM THE 30S ACROSS THE EASTERN JAMES VALLEY
AND UPPER 40S ACROSS WESTERN NORTH DAKOTA. TEMPERATURES IN THE 50S
ARE POSSIBLE EARLY NEXT WEEK.
SEVERAL WEAK CLIPPERS WILL SWING THROUGH THE AREA DURING THE
EXTENDED PERIOD. THE FIRST SUCH CLIPPER IS EXPECTED TO AFFECT THE
AREA SATURDAY INTO SUNDAY...WITH THE OTHER TWO ARRIVING MONDAY AND
THURSDAY.
FOR SATURDAY INTO SUNDAY...LATEST GUIDANCE SEEMS TO HAVE TAKEN A STEP
BACKWARD AS FAR AS CONSISTENCY AND AGREEMENT ARE CONCERNED. THE 12
UTC ECMWF IS MORE PROGRESSIVE AND BULLISH WITH QPF AMOUNTS ACROSS
WESTERN AND CENTRAL NORTH DAKOTA. WHEREAS THE GFS AND SREF ARE
SLOWER AND MAINLY DRY. THE NAM INITIALLY KEEPS PRECIP OUT OF THE
AREA AS THE CLIPPER SLIDES ACROSS EASTERN NORTH DAKOTA...BUT THEN
BRINGS SOME WRAP-AROUND PRECIP INTO WESTERN NORTH DAKOTA. DUE TO
THE WIDE RANGE OF MODEL SOLUTIONS CONFIDENCE ON ANY PARTICULAR
SCENARIO IS RATHER LOW. THEREFORE...KEPT PRECIP CHANCES BELOW 25
PERCENT THROUGH SUNDAY. LOOKING AT FORECAST SOUNDING PROFILES IT
WOULD APPEAR THAT THE MOST FAVORED PRECIP TYPE (IF PRECIPITATION
DOES IN FACT FORM) WOULD BE RAIN ACROSS THE MAJORITY OF THE AREA.
WITH COOLER TEMPERATURES ALOFT AND AT THE SURFACE FURTHER EAST...A
MIX OF FREEZING DRIZZLE OR SNOW FLURRIES ARE POSSIBLE ALONG AND
EAST OF HWY 281. WITH QPF AMOUNTS EXPECTED TO BE LIGHT...OR
POTENTIALLY NONEXISTENT DEPENDING ON WHAT GUIDANCE YOU
BELIEVE...IMPACTS SHOULD BE MINIMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 957 PM CST THU JAN 22 2015
LCL -RA/-FZRA WILL BE POSSIBLE TONIGHT OVER PORTIONS OF FAR
NORTHERN AND CENTRAL NORTH DAKOTA...THOUGH CHANCES FOR THIS REMAIN
QUITE LOW. OTHERWISE...VFR CONDITIONS ARE EXPECTED. MODERATE
SOUTHWEST TO WEST FLOW TONIGHT SHIFTING WEST TO NORTHWEST ON
FRIDAY.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...JJS
LONG TERM...AJ
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
104 PM CST WED JAN 21 2015
.UPDATE...
ISSUED AT 102 PM CST WED JAN 21 2015
CLEARING HOLE DROPPING SLOWLY SOUTH CENTERED OVER GRAND FORKS
ATTM. WHILE CLOUDS DROPPING BACK SOUTH INTO FAR NE ND FROM
MANITOBA. ARE SEEING A FEW BREAKS THOUGH FARTHER SOUTHWEST TO THE
NORTH OF JAMESTOWN AS WELL. HRRR AND OTHER MODELS INSIST ON DRYING
OUT THAT 925-850 MB LAYER THIS EVENING AND TONIGHT. WE SHALL SEE.
TEMPS APPEAR OK.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 314 AM CST WED JAN 21 2015
LIGHT PRECIP CHANCES CONTINUE TO BE THE CHALLENGE FOR TODAY.
NORTHWESTERLY FLOW ALOFT WITH WEAK SHORTWAVES MOVING THROUGH WILL
CONTINUE. ONE SUCH SHORTWAVE IS CURRENTLY DIGGING INTO THE
NORTHERN RED RIVER VALLEY...AND THERE HAS BEEN AN INCREASE IN VERY
LIGHT RADAR RETURNS. OUTSIDE THE OFFICE HERE IN GFK IT SEEMS TO BE
MOSTLY VERY LIGHT FREEZING DRIZZLE...BUT LOOKING AT MODEL
SOUNDINGS THAT ARE QUICKLY SATURATED AND SOME OBS AT LANGDON AND
CAVALIER SHOWING SNOW...CANNOT RULE OUT A FEW FLAKES. THE RAP
CONTINUES TO KEEP THE BEST QPF TO THE WEST AND INTO THE SOUTHERN
CWA...BUT HAS A FEW BLIPS IN THE CENTRAL AND NORTH. THINK THAT THE
BEST CHANCES FOR ACCUMULATING SNOW WILL REMAIN IN THE SOUTH...BUT
SOME PATCHY FOG...FREEZING DRIZZLE AND A BIT OF LIGHT SNOW WILL
LINGER IN THE NORTH FOR A LITTLE WHILE THIS MORNING.
WITH SHORTWAVES DIGGING DOWN...THERE HAS BEEN SOME FAIRLY STRONG
COLD AIR ADVECTION ALONG THE NORTHERN BORDER. CLOUDS HAVE KEPT
TEMPS IN THE 20S...BUT THINK THAT SOME COLDER AIR WILL MOVE IN
DURING THE DAY AS HIGH PRESSURE ARRIVES OVER THE NORTHERN PLAINS.
THE HIGH WILL BE A DIRTY ONE...WITH QUITE A LOT OF LOW LEVEL
MOISTURE SEEN PRETTY FAR UP INTO MANITOBA. THINK THAT THE CLOUDS
WILL STICK AROUND FOR MUCH OF THE DAY. WITH THE CLOUDS AND COLD
AIR ADVECTION...MANY SPOTS HAVE ALREADY SEEN THEIR HIGH FOR THE
DAY.
NORTH TO NORTHWESTERLY FLOW ALOFT WILL CONTINUE INTO TONIGHT AND
THURSDAY. A SFC LOW WILL DEVELOP OVER SOUTHERN CANADA...ALLOWING
WINDS TO INCREASE AND SHIFT TO A MORE SOUTHWESTERLY DIRECTION.
WITH WINDS PICKING UP AND WARM AIR ADVECTION RETURNING THINK THE
LOW WILL BE FAIRLY EARLY AS WE BOTTOM OUT IN THE EVENING AND THEN
TEMPS START TO RISE LATE IN THE NIGHT. THE PRESSURE GRADIENT OVER
THE CWA WILL ONLY INCREASE THROUGH THURSDAY. WITH WARMER AIR
MOVING BACK IN THE TEMPS SHOULD BE MILD AND BACK UP INTO THE 20S
AND LOW 30S...BUT WITH THE WINDS BECOMING BREEZY IT MAY NOT FEEL
AS NICE.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 314 AM CST WED JAN 21 2015
THURSDAY NIGHT THROUGH FRIDAY NIGHT...THE MODELS BRING ANOTHER
SHORTWAVE THROUGH MANITOBA INTO NORTHERN MN. MODELS HAVE BEEN VERY
INCONSISTENT WITH THIS SYSTEM. THE ECMWF/GEM HAS SEVERAL TENTHS OF
QPF AND THE NAM IS COMPLETELY DRY...WITH THE GFS IN BETWEEN. GIVEN
RECENT MODEL PERFORMANCE WILL LEAN A BIT CLOSER TO THE DRY SIDE
AND JUST HAVE SOME VERY LOW POPS FOR THURSDAY NIGHT AND FRIDAY.
THE WARM AIR ADVECTION UP TO THEN WILL CREATE A FAIRLY STRONG WARM
LAYER ALOFT...WITH MORE QUESTION IF THERE WILL BE ENOUGH MOISTURE
FOR ACTUAL PRECIP AND NOT JUST FZDZ. FOR NOW JUST WENT WITH A
SLIGHT CHANCE FOR FZRA/SLEET AND WILL ADJUST AS NEEDED. TEMPS WILL
BE MILD THURSDAY NIGHT WITH THE READINGS MAKING A RUN FOR THE 35
TO 40 RANGE AGAIN ON FRIDAY. BY FRIDAY NIGHT THE MODELS SHOW SIGNS
OF A BACKDOOR COLD FRONT STARTING TO MOVE INTO THE NORTHEASTERN
COUNTIES. WENT A BIT COLDER AND MAY HAVE TO DROP MORE DEPENDING ON
HOW STRONG THE COLD AIR ADVECTION IS AND IF WE GET ANY CLEARING
FRIDAY NIGHT.
FOR SATURDAY THROUGH TUESDAY...WILL ESSENTIALLY REMAIN IN NORTHWEST
FLOW ALOFT YET FOR THE DURATION. STILL LOOKS LIKE A SYSTEM SPREADING
IN FOR SATURDAY FROM THE NORTH-NW. TEMPS LOOK TO REMAIN QUITE MILD
SO DETERMINING PCPN TYPE MAY BE AN ISSUE. THIS SYSTEM SHOULD PUSH TO
THE EAST SAT NIGHT INTO SUNDAY BUT THE ISSUES WITH PCPN TYPE WILL
REMAIN. FOR NOW MENTIONED RAIN OR SNOW IN AREAS THAT APPEAR TO BE
QUESTIONABLE AND WILL TRY TO RESOLVE THESE BETTER CLOSER TO THE
EVENT. MODELS SHOW A WEAKER TRAILING LOW SUNDAY NIGHT THAT MAINLY
AFFECTS THE NORTHEAST FA WITH SOME LIGHT SNOW. MAY BE A BRIEF BREAK
ON MON BEFORE ANOTHER LOW DROPS IN FOR MONDAY NIGHT INTO EARLY TUE.
THIS SYSTEM AGAIN LOOKS TO MAINLY AFFECT NORTHERN AND EASTERN AREAS
BUT STILL QUITE A BIT OF UNCERTAINTY THIS FAR OUT. OVERALL TEMPS
INTO EARLY NEXT WEEK LOOK TO REMAIN ABOVE NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 102 PM CST WED JAN 21 2015
PREDOMINANTLY MVFR CIGS WILL LINGER THROUGH THE MID EVENING HOURS
TONIGHT AS A RIDGE AXIS SLIPS SOUTH. A HOLE OVER THE NORTHERN RED
RIVER VALLEY WILL BRING A COUPLE HOUR BREAK IN SKY COVER TO GFK AND
MAY SINK AS FAR SOUTH AS FAR...BUT WILL KEEP MVFR FOR FAR AT THIS
TIME (NOT ENOUGH CONFIDENCE TO CLEAR THINGS OUT FOR A BRIEF PERIOD).
NORTHERLY WINDS WILL SHIFT SOUTHWEST BY MORNING AND THE MVFR DECK
SHOULD GRADUALLY ERODE TONIGHT...EXPECTING VFR CONDS BY 03Z TO 06Z
TIMEFRAME.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...RIDDLE
SHORT TERM...JR
LONG TERM...JR/GODON
AVIATION...SPEICHER
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1236 PM CST WED JAN 21 2015
.UPDATE...
ISSUED AT 1234 PM CST WED JAN 21 2015
THIS UPDATE HAVE KEPT THE FLURRY WORDING IN THE FORECAST AND
DELAYED THE EXIT OF FLURRIES IN THE JAMES RIVER VALLEY. ALSO
DROPPED FOG FROM THE FORECAST AS RECENT OBSERVATIONS NO LONGER
SUPPORT AREAS OF FOG IN THE SOUTHERN JAMES RIVER VALLEY.
UPDATE ISSUED AT 1035 AM CST WED JAN 21 2015
THIS UPDATE HAVE OPTED TO DROP ALL POPS AND JUST GO WITH
CATEGORICAL SNOW FLURRIES. RADAR INDICATES POCKETS OF LIGHT SNOW
AND FLURRIES MOVING SOUTH THROUGH THE FORECAST AREA...WITH THE
BACK EDGE ABOUT FROM GARRISON TO HARVEY. THERE IS ANOTHER BATCH OF
-SN IN EASTERN MONTANA...PUSHING TOWARD THE NORTH DAKOTA BORDER.
SOME FOG IN THE JAMES RIVER VALLEY PERSISTS AND THE RISK OF
FREEZING DRIZZLE IN THE SOUTHERN JAMES RIVER VALLEY CONTINUES AS
MODEL SOUNDINGS SUGGEST THERE MAY BE LITTLE TO NO ICE IN THE
CLOUDS ABOVE THAT AREA...FORCING THE RISK THAT THERE COULD BE SOME
FREEZING DRIZZLE.
HAVE LOWERED TEMPERATURES FAR NORTHEAST...ROLLA AREA...BASED ON
THE NWS GRAND FORKS LEAD THERE. THEY LOWERED HIGH TEMPERATURES
FORECAST FOR TODAY UP AGAINST THAT AREA AND IT IS A REASONABLE
EXPECTATION.
UPDATE ISSUED AT 652 AM CST WED JAN 21 2015
DID ADD A MENTION OF PATCHY FREEZING DRIZZLE TO THE JAMES RIVER
VALLEY THIS MORNING FOR JAMESTOWN AND POINTS SOUTH. SATELLITE
TRENDS THROUGH 1230 UTC SUPPORT A POTENTIAL VOID OF ICE
CRYSTALS...WHICH IS EXPECTED TO CONTINUE THROUGH POTENTIALLY 15
UTC GIVEN THE 11 UTC RAP SOUNDINGS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 331 AM CST WED JAN 21 2015
CURRENTLY...A SURFACE LOW WAS OVER IOWA WITH A COLD FRONT EXTENDING
NORTHWESTWARD TOWARDS A SECONDARY LOW OVER NORTHEASTERN SOUTH DAKOTA
IN THE JAMES VALLEY NEAR THE NORTH DAKOTA BORDER. AN INVERTED TROUGH
EXTENDED FROM THIS SECONDARY LOW NORTHWARD TO BETWEEN
BISMARCK/JAMESTOWN AND BETWEEN MINOT/RUGBY. EAST OF THIS INVERTED
TROUGH WINDS WERE NORTHEAST AND AREAS OF LIGHT FOG PERSISTED THROUGH
THE NIGHTTIME HOURS. WEST OF THIS INVERTED TROUGH WINDS WERE FROM
THE NORTHWEST...WITH MODERATING TEMPERATURES IN THE UPPER 20S AND
LOWER 30S - INDICATIVE OF THE INFLUENCE OF THE PACIFIC HIGH THAT
EXTENDED OVER MONTANA/IDAHO/WYOMING. A POLAR HIGH PRESSURE AIRMASS
WAS CENTERED OVER SOUTHERN MANITOBA AND COLDER AIR WAS FILTERING
INTO NORTHERN NORTH DAKOTA WHERE TEMPERATURES HAD DROPPED INTO THE
TEENS. AN UPPER LEVEL SHORTWAVE WAS EVIDENT ON THE SATELLITE WATER
VAPOR LOOP - MAINLY CENTERED OVER LAKE SAKAKAWEA. LIGHT SNOW
CONTINUED MOVING SOUTH FROM SOUTHERN MANITOBA AND SOUTHERN
SASKATCHEWAN INTO NORTH DAKOTA.
LATEST MODELS INDICATE THE UPPER LEVEL SHORTWAVE WILL CONTINUE ITS
MOVEMENT SOUTHWARD INTO SOUTH DAKOTA THIS AFTERNOON. CURRENT
FORECAST ON TRACK WITH CHANCES OF LIGHT SNOW DECREASING FROM NORTH
TO SOUTH TODAY. BY NOON THE SNOW SHOULD END IN THE NORTH...WITH SNOW
ENDING IN THE SOUTH DURING THE AFTERNOON. ADDITIONAL ACCUMULATIONS
AFTER 4 AM CST SHOULD BE LIGHT - UP TO A COUPLE OF TENTHS OF AN
INCH.
THE POLAR HIGH PRESSURE OVER MANITOBA THIS MORNING IS FORECAST TO
MOVE SOUTH INTO THE RED RIVER VALLEY. MEANWHILE THE MILD PACIFIC
HIGH TO OUR SOUTHWEST IS FORECAST TO NUDGE EASTWARD. HIGHS TODAY
SHOULD RANGE FROM THE TEENS IN THE TURTLE MOUNTAINS (NEAR THE POLAR
HIGH) TO THE LOWER 30S IN THE FAR SOUTHWEST.
TONIGHT A VIGOROUS LOW PRESSURE SYSTEM MOVING EAST OUT OF THE
CANADIAN ROCKIES TOWARDS HUDSON BAY WILL GENERATE A RATHER TIGHT
SURFACE PRESSURE GRADIENT...INDUCING STRENGTHENING SOUTHWESTERLY
WINDS ACROSS NORTH DAKOTA. OVERNIGHT LOWS IN THE TEENS SHOULD BE
REACHED DURING THE EVENING...THEN STEADY OR RISING TEMPERATURES LATE
TONIGHT AS SOUTHWEST WINDS INCREASE...SETTING UP A MILD DAY FOR
THURSDAY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 331 AM CST WED JAN 21 2015
ABOVE NORMAL TEMPERATURES HIGHLIGHT THE EXTENDED FORECAST.
HIGHS IN THE 30S AND 40S ARE FORECAST ACROSS WESTERN AND CENTRAL
NORTH DAKOTA THROUGH THE EXTENDED FORECAST AS THE NORTHERN PLAINS
IS EXPECTED TO REMAIN ON THE EASTERN PERIPHERY OF THE MEAN
WESTERN CONUS UPPER LEVEL RIDGE. THE ONLY MENTION OF PRECIPITATION
IN THE PERIOD IS ON SATURDAY INTO SATURDAY NIGHT. THE 00 UTC
GUIDANCE SUITE CONTINUES AGREEMENT FROM EARLIER ITERATIONS OF A
CLIPPER SYSTEM TO IMPACT THE REGION. GIVEN HIGHS FORECAST TO BE IN
THE 40S WEST...AND 30S CENTRAL ON SATURDAY...MOSTLY RAIN IS
EXPECTED ACROSS THE WEST...WITH A RAIN AND SNOW MIX CENTRAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY MORNING)
ISSUED AT 1035 AM CST WED JAN 21 2015
MVFR CEILINGS AND VISIBILITIES WILL CONTINUE INTO THE MID AFTERNOON
ACROSS THE SOUTH IN LIGHT SNOW. LIFR POSSIBLE AT KJMS IN BR AND AREAS
OF FREEZING DRIZZLE. ACROSS THE NORTH...GENERALLY VFR BUT WITH PATCHES
OF LOWER CEILINGS IN THE MVFR CATEGORY WITH VERY HIGH MOISTURE IN
THE LOWER LEVELS OF THE ATMOSPHERE.
IMPROVING SLOWLY EVERYWHERE AFTER 22/03Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MM
SHORT TERM...JV
LONG TERM...AYD
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1043 AM CST WED JAN 21 2015
.UPDATE...
ISSUED AT 1035 AM CST WED JAN 21 2015
THIS UPDATE HAVE OPTED TO DROP ALL POPS AND JUST GO WITH
CATEGORICAL SNOW FLURRIES. RADAR INDICATES POCKETS OF LIGHT SNOW
AND FLURRIES MOVING SOUTH THROUGH THE FORECAST AREA...WITH THE
BACK EDGE ABOUT FROM GARRISON TO HARVEY. THERE IS ANOTHER BATCH OF
-SN IN EASTERN MONTANA...PUSHING TOWARD THE NORTH DAKOTA BORDER.
SOME FOG IN THE JAMES RIVER VALLEY PERSISTS AND THE RISK OF
FREEZING DRIZZLE IN THE SOUTHERN JAMES RIVER VALLEY CONTINUES AS
MODEL SOUNDINGS SUGGEST THERE MAY BE LITTLE TO NO ICE IN THE
CLOUDS ABOVE THAT AREA...FORCING THE RISK THAT THERE COULD BE SOME
FREEZING DRIZZLE.
HAVE LOWERED TEMPERATURES FAR NORTHEAST...ROLLA AREA...BASED ON
THE NWS GRAND FORKS LEAD THERE. THEY LOWERED HIGH TEMPERATURES
FORECAST FOR TODAY UP AGAINST THAT AREA AND IT IS A REASONABLE
EXPECTATION.
UPDATE ISSUED AT 652 AM CST WED JAN 21 2015
DID ADD A MENTION OF PATCHY FREEZING DRIZZLE TO THE JAMES RIVER
VALLEY THIS MORNING FOR JAMESTOWN AND POINTS SOUTH. SATELLITE
TRENDS THROUGH 1230 UTC SUPPORT A POTENTIAL VOID OF ICE
CRYSTALS...WHICH IS EXPECTED TO CONTINUE THROUGH POTENTIALLY 15
UTC GIVEN THE 11 UTC RAP SOUNDINGS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 331 AM CST WED JAN 21 2015
CURRENTLY...A SURFACE LOW WAS OVER IOWA WITH A COLD FRONT EXTENDING
NORTHWESTWARD TOWARDS A SECONDARY LOW OVER NORTHEASTERN SOUTH DAKOTA
IN THE JAMES VALLEY NEAR THE NORTH DAKOTA BORDER. AN INVERTED TROUGH
EXTENDED FROM THIS SECONDARY LOW NORTHWARD TO BETWEEN
BISMARCK/JAMESTOWN AND BETWEEN MINOT/RUGBY. EAST OF THIS INVERTED
TROUGH WINDS WERE NORTHEAST AND AREAS OF LIGHT FOG PERSISTED THROUGH
THE NIGHTTIME HOURS. WEST OF THIS INVERTED TROUGH WINDS WERE FROM
THE NORTHWEST...WITH MODERATING TEMPERATURES IN THE UPPER 20S AND
LOWER 30S - INDICATIVE OF THE INFLUENCE OF THE PACIFIC HIGH THAT
EXTENDED OVER MONTANA/IDAHO/WYOMING. A POLAR HIGH PRESSURE AIRMASS
WAS CENTERED OVER SOUTHERN MANITOBA AND COLDER AIR WAS FILTERING
INTO NORTHERN NORTH DAKOTA WHERE TEMPERATURES HAD DROPPED INTO THE
TEENS. AN UPPER LEVEL SHORTWAVE WAS EVIDENT ON THE SATELLITE WATER
VAPOR LOOP - MAINLY CENTERED OVER LAKE SAKAKAWEA. LIGHT SNOW
CONTINUED MOVING SOUTH FROM SOUTHERN MANITOBA AND SOUTHERN
SASKATCHEWAN INTO NORTH DAKOTA.
LATEST MODELS INDICATE THE UPPER LEVEL SHORTWAVE WILL CONTINUE ITS
MOVEMENT SOUTHWARD INTO SOUTH DAKOTA THIS AFTERNOON. CURRENT
FORECAST ON TRACK WITH CHANCES OF LIGHT SNOW DECREASING FROM NORTH
TO SOUTH TODAY. BY NOON THE SNOW SHOULD END IN THE NORTH...WITH SNOW
ENDING IN THE SOUTH DURING THE AFTERNOON. ADDITIONAL ACCUMULATIONS
AFTER 4 AM CST SHOULD BE LIGHT - UP TO A COUPLE OF TENTHS OF AN
INCH.
THE POLAR HIGH PRESSURE OVER MANITOBA THIS MORNING IS FORECAST TO
MOVE SOUTH INTO THE RED RIVER VALLEY. MEANWHILE THE MILD PACIFIC
HIGH TO OUR SOUTHWEST IS FORECAST TO NUDGE EASTWARD. HIGHS TODAY
SHOULD RANGE FROM THE TEENS IN THE TURTLE MOUNTAINS (NEAR THE POLAR
HIGH) TO THE LOWER 30S IN THE FAR SOUTHWEST.
TONIGHT A VIGOROUS LOW PRESSURE SYSTEM MOVING EAST OUT OF THE
CANADIAN ROCKIES TOWARDS HUDSON BAY WILL GENERATE A RATHER TIGHT
SURFACE PRESSURE GRADIENT...INDUCING STRENGTHENING SOUTHWESTERLY
WINDS ACROSS NORTH DAKOTA. OVERNIGHT LOWS IN THE TEENS SHOULD BE
REACHED DURING THE EVENING...THEN STEADY OR RISING TEMPERATURES LATE
TONIGHT AS SOUTHWEST WINDS INCREASE...SETTING UP A MILD DAY FOR
THURSDAY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 331 AM CST WED JAN 21 2015
ABOVE NORMAL TEMPERATURES HIGHLIGHT THE EXTENDED FORECAST.
HIGHS IN THE 30S AND 40S ARE FORECAST ACROSS WESTERN AND CENTRAL
NORTH DAKOTA THROUGH THE EXTENDED FORECAST AS THE NORTHERN PLAINS
IS EXPECTED TO REMAIN ON THE EASTERN PERIPHERY OF THE MEAN
WESTERN CONUS UPPER LEVEL RIDGE. THE ONLY MENTION OF PRECIPITATION
IN THE PERIOD IS ON SATURDAY INTO SATURDAY NIGHT. THE 00 UTC
GUIDANCE SUITE CONTINUES AGREEMENT FROM EARLIER ITERATIONS OF A
CLIPPER SYSTEM TO IMPACT THE REGION. GIVEN HIGHS FORECAST TO BE IN
THE 40S WEST...AND 30S CENTRAL ON SATURDAY...MOSTLY RAIN IS
EXPECTED ACROSS THE WEST...WITH A RAIN AND SNOW MIX CENTRAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY MORNING)
ISSUED AT 1035 AM CST WED JAN 21 2015
MVFR CEILINGS AND VISIBILITIES WILL CONTINUE INTO THE MID AFTERNOON
ACROSS THE SOUTH IN -SN. LIFR POSSIBLE AT KJMS IN BR AND AREAS OF -ZL.
ACROSS THE NORTH...GENERALLY VFR BUT WITH PATCHES OF LOWER
CEILINGS IN THE MVFR CATEGORY WITH VERY HIGH MOISTURE IN THE LOWER
LEVELS OF THE ATMOSPHERE.
IMPROVING SLOWLY EVERYWHERE AFTER 22/03Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JPM
SHORT TERM...JV
LONG TERM...AYD
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS BISMARCK ND
653 AM CST WED JAN 21 2015
.UPDATE...
ISSUED AT 652 AM CST WED JAN 21 2015
DID ADD A MENTION OF PATCHY FREEZING DRIZZLE TO THE JAMES RIVER
VALLEY THIS MORNING FOR JAMESTOWN AND POINTS SOUTH. SATELLITE
TRENDS THROUGH 1230 UTC SUPPORT A POTENTIAL VOID OF ICE
CRYSTALS...WHICH IS EXPECTED TO CONTINUE THROUGH POTENTIALLY 15
UTC GIVEN THE 11 UTC RAP SOUNDINGS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 331 AM CST WED JAN 21 2015
CURRENTLY...A SURFACE LOW WAS OVER IOWA WITH A COLD FRONT EXTENDING
NORTHWESTWARD TOWARDS A SECONDARY LOW OVER NORTHEASTERN SOUTH DAKOTA
IN THE JAMES VALLEY NEAR THE NORTH DAKOTA BORDER. AN INVERTED TROUGH
EXTENDED FROM THIS SECONDARY LOW NORTHWARD TO BETWEEN
BISMARCK/JAMESTOWN AND BETWEEN MINOT/RUGBY. EAST OF THIS INVERTED
TROUGH WINDS WERE NORTHEAST AND AREAS OF LIGHT FOG PERSISTED THROUGH
THE NIGHTTIME HOURS. WEST OF THIS INVERTED TROUGH WINDS WERE FROM
THE NORTHWEST...WITH MODERATING TEMPERATURES IN THE UPPER 20S AND
LOWER 30S - INDICATIVE OF THE INFLUENCE OF THE PACIFIC HIGH THAT
EXTENDED OVER MONTANA/IDAHO/WYOMING. A POLAR HIGH PRESSURE AIRMASS
WAS CENTERED OVER SOUTHERN MANITOBA AND COLDER AIR WAS FILTERING
INTO NORTHERN NORTH DAKOTA WHERE TEMPERATURES HAD DROPPED INTO THE
TEENS. AN UPPER LEVEL SHORTWAVE WAS EVIDENT ON THE SATELLITE WATER
VAPOR LOOP - MAINLY CENTERED OVER LAKE SAKAKAWEA. LIGHT SNOW
CONTINUED MOVING SOUTH FROM SOUTHERN MANITOBA AND SOUTHERN
SASKATCHEWAN INTO NORTH DAKOTA.
LATEST MODELS INDICATE THE UPPER LEVEL SHORTWAVE WILL CONTINUE ITS
MOVEMENT SOUTHWARD INTO SOUTH DAKOTA THIS AFTERNOON. CURRENT
FORECAST ON TRACK WITH CHANCES OF LIGHT SNOW DECREASING FROM NORTH
TO SOUTH TODAY. BY NOON THE SNOW SHOULD END IN THE NORTH...WITH SNOW
ENDING IN THE SOUTH DURING THE AFTERNOON. ADDITIONAL ACCUMULATIONS
AFTER 4 AM CST SHOULD BE LIGHT - UP TO A COUPLE OF TENTHS OF AN
INCH.
THE POLAR HIGH PRESSURE OVER MANITOBA THIS MORNING IS FORECAST TO
MOVE SOUTH INTO THE RED RIVER VALLEY. MEANWHILE THE MILD PACIFIC
HIGH TO OUR SOUTHWEST IS FORECAST TO NUDGE EASTWARD. HIGHS TODAY
SHOULD RANGE FROM THE TEENS IN THE TURTLE MOUNTAINS (NEAR THE POLAR
HIGH) TO THE LOWER 30S IN THE FAR SOUTHWEST.
TONIGHT A VIGOROUS LOW PRESSURE SYSTEM MOVING EAST OUT OF THE
CANADIAN ROCKIES TOWARDS HUDSON BAY WILL GENERATE A RATHER TIGHT
SURFACE PRESSURE GRADIENT...INDUCING STRENGTHENING SOUTHWESTERLY
WINDS ACROSS NORTH DAKOTA. OVERNIGHT LOWS IN THE TEENS SHOULD BE
REACHED DURING THE EVENING...THEN STEADY OR RISING TEMPERATURES LATE
TONIGHT AS SOUTHWEST WINDS INCREASE...SETTING UP A MILD DAY FOR
THURSDAY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 331 AM CST WED JAN 21 2015
ABOVE NORMAL TEMPERATURES HIGHLIGHT THE EXTENDED FORECAST.
HIGHS IN THE 30S AND 40S ARE FORECAST ACROSS WESTERN AND CENTRAL
NORTH DAKOTA THROUGH THE EXTENDED FORECAST AS THE NORTHERN PLAINS
IS EXPECTED TO REMAIN ON THE EASTERN PERIPHERY OF THE MEAN
WESTERN CONUS UPPER LEVEL RIDGE. THE ONLY MENTION OF PRECIPITATION
IN THE PERIOD IS ON SATURDAY INTO SATURDAY NIGHT. THE 00 UTC
GUIDANCE SUITE CONTINUES AGREEMENT FROM EARLIER ITERATIONS OF A
CLIPPER SYSTEM TO IMPACT THE REGION. GIVEN HIGHS FORECAST TO BE IN
THE 40S WEST...AND 30S CENTRAL ON SATURDAY...MOSTLY RAIN IS
EXPECTED ACROSS THE WEST...WITH A RAIN AND SNOW MIX CENTRAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 653 AM CST WED JAN 21 2015
GENERALLY IFR CONDITIONS IN LIGHT SNOW AND FOG WILL CONTINUE OVER
WESTERN AND CENTRAL NORTH DAKOTA FOR THE MORNING HOURS. LIFR
POSSIBLE AT KJMS IN FOG AND PATCHY LIGHT FREEZING DRIZZLE.
CONDITIONS WILL IMPROVE SLOWLY TO MVFR/VFR FROM NORTH TO SOUTH
WEDNESDAY AFTERNOON AND EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AYD
SHORT TERM...JV
LONG TERM...AYD
AVIATION...AYD
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
105 PM EST WED JAN 21 2015
.SYNOPSIS...
A SERIES OF WEATHER DISTURBANCES WILL MOVE THROUGH THE OHIO
VALLEY THROUGH TONIGHT...BRINGING OCCASIONAL CHANCES FOR LIGHT
RAIN AND SNOW. SLIGHTLY COOLER AIR WILL MOVE INTO THE REGION
THROUGH THE REST OF THE WEEK...WITH HIGH PRESSURE PROVIDING DRY
CONDITIONS. AN APPROACHING LOW PRESSURE SYSTEM FROM THE SOUTH MAY
BRING A WINTRY MIX TO AREAS ALONG AND SOUTH OF THE OHIO RIVER BY
FRIDAY EVENING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A S/WV OVER NRN ILLINOIS THIS MORNING WILL SHEAR AS IT MOVES
EAST/SOUTHEAST TO OUR REGION BY THIS EVENING. PER SATELLITE
IMAGERY...LOW CLOUDS SHOULD HOLD ACRS THE NRN ZONES THROUGH THE
AFTERNOON. FOR THE SOUTHERN ZONES...SKIES WILL BECOME PARTLY
CLOUDY...PERHAPS EVEN MOSTLY SUNNY...FOR A PERIOD BEFORE LOW
CLOUDS MOVE BACK IN THIS EVENING AND OVERNIGHT. HIGHS RES MODELS
SUGGEST PCPN GENERATED FROM THE S/WV WILL BE SHOWERY IN NATURE.
THIS IS SUPPORTED BY SOME WEAK INSTABILITY BY THE RAP MODEL. HAVE
KEPT A CHANCE FOR SNOW SHOWERS ACRS THE FAR NORTH. POINTS FARTHER
SOUTH...THE BOUNDARY LAYER WILL BE WARM ENOUGH FOR A RAIN/SNOW
SHOWER MIX JUST NORTH OF I-70...WITH RAIN SHOWERS ALONG AND SOUTH
OF I-70. TEMPERATURES ARE EXPECTED TO BE WARMER OVER THE SOUTH WITH
MORE SUNSHINE. HAVE TEMPERATURES RANGING FROM THE MID 30S FAR
NORTH TO THE UPPER 40S SOUTH OF THE OHIO RIVER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
LINGERED LIGHT CHANCES OF PRECIPITATION TONIGHT AS AMPLE LL
MOISTURE COULD CREATE SOME FLURRIES/LIGHT SNOW SHOWERS/LIGHT RAIN
SHOWERS. LINGERED CLOUDS IN NW FLOW AND CAA. BEFORE THE LOWER
LAYERS DRY OUT AND SOME CLEARING ON LATE THURSDAY/EARLY FRIDAY.
WHILE FCST AREA REMAINS UNDER QUIET RIDGING AND CAA...A DEEPENING
TROUGH FROM THE SOUTHERN PLAINS APPROACHES THE MID OHIO VALLEY BY
FRIDAY NIGHT INTO SATURDAY. EACH MODEL RUN OF THE GFS/ECMWF AND
ESPECIALLY THE NAM ARE QUICKER AND FURTHER NORTH WITH THE
PRECIPITATION ONSET. THERE IS POTENTIAL FOR ACCUMULATING SNOW IN
THE FAR SE FCST AREA WITH THIS SYSTEM...WORTH A MENTION IN THE
HAZARDOUS WEATHER OUTLOOKS...AND MAY YIELD ADVISORY LEVEL SNOWFALL
IN THE SOUTHEAST.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
MODELS ARE NOT IN AGREEMENT ON A SYSTEM THAT IS EXPECTED TO MOVE
THROUGH THE AREA SUNDAY INTO MONDAY. THE GFS KEEPS MOST OF THE
PRECIPITATION SOUTH OF THE AREA WITH THIS SYSTEM WHILE THE ECMWF
LINGERS PRECIPITATION ACROSS THE AREA THROUGH ALMOST THE ENTIRE
SUNDAY TO MONDAY TIME FRAME. WENT CLOSER TO THE ECMWF SOLUTION
HOWEVER KEPT PRECIPITATION CHANCES CONFINED TO THE CHANGE CATEGORY
FOR MOST LOCATIONS AT THIS TIME. TEMPERATURES WILL BE COOL ENOUGH
THAT ANY PRECIPITATION THAT DOES OCCUR SUNDAY INTO MONDAY WILL BE
IN THE FORM OF SNOW. AFTER THIS TIME HIGH PRESSURE WILL BUILD INTO
THE AREA FOR TUESDAY.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AN UPPER LEVEL DISTURBANCE WILL SHEAR AS IT MOVE SOUTHEAST THROUGH
THE REGION THIS AFTERNOON AND THIS EVENING. THIS FEATURE WILL
BRING SOME SCATTERED LIGHT SHOWERS TO THE NORTHERN TAF SITES. AT
THE SAME TYPE...IT LOOKS LIKE CEILINGS WILL TRY TO LIFT TO VFR FOR
A PERIOD OF TIME AHEAD OF A WEAK SURFACE LOW. ONCE THE LOW GOES
BY...A WEAK BOUNDARY WILL PUSH SOUTHEAST. LOW LEVEL MOISTURE AND
COLD AIR ADVECTION BEHIND THIS BOUNDARY WILL BRING A RETURN TO
MVFR AND EVENTUALLY IFR CEILINGS. WINDS WILL DIMINISH AND SOME
MVFR VSBYS IN MIST MAY DEVELOP OVERNIGHT.
ON THURSDAY...SURFACE HIGH PRESSURE WILL BUILD EAST INTO THE
REGION. LOW LEVEL MOISTURE WILL BE TRAPPED UNDER THE BUILDING
RIDGE AND WILL LINGER INTO THURSDAY. CEILINGS SHOULD RISE INTO THE
MVFR CATEGORY WITH VISIBILITIES RETURNING TO VFR DUE TO DAYTIME
HEATING. MODELS ARE IN DISAGREEMENT IN DETERMINING WHETHER CEILINGS
WILL ERODE GOING INTO THURSDAY NIGHT OR REMAINING TRAPPED UNDER THE
HIGH.
OUTLOOK...MVFR/IFR CEILINGS AND VISIBILITIES POSSIBLE SUNDAY INTO
SUNDAY NIGHT. MVFR CEILINGS POSSIBLE ON MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JDR
NEAR TERM...HICKMAN
SHORT TERM...JDR
LONG TERM...NOVAK
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
932 AM EST WED JAN 21 2015
.SYNOPSIS...
A SERIES OF WEATHER DISTURBANCES WILL MOVE THROUGH THE OHIO
VALLEY THROUGH TONIGHT...BRINGING OCCASIONAL CHANCES FOR LIGHT
RAIN AND SNOW. SLIGHTLY COOLER AIR WILL MOVE INTO THE REGION
THROUGH THE REST OF THE WEEK...WITH HIGH PRESSURE PROVIDING DRY
CONDITIONS. AN APPROACHING LOW PRESSURE SYSTEM FROM THE SOUTH MAY
BRING A WINTRY MIX TO AREAS ALONG AND SOUTH OF THE OHIO RIVER BY
FRIDAY EVENING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A S/WV OVER NRN ILLINOIS THIS MORNING WILL SHEAR AS IT MOVES
EAST/SOUTHEAST TO OUR REGION BY THIS EVENING. PER SATELLITE
IMAGERY...LOW CLOUDS SHOULD HOLD ACRS THE NRN ZONES THROUGH THE
AFTERNOON. FOR THE SOUTHERN ZONES...SKIES WILL BECOME PARTLY
CLOUDY...PERHAPS EVEN MOSTLY SUNNY...FOR A PERIOD BEFORE LOW
CLOUDS MOVE BACK IN THIS EVENING AND OVERNIGHT. HIGHS RES MODELS
SUGGEST PCPN GENERATED FROM THE S/WV WILL BE SHOWERY IN NATURE.
THIS IS SUPPORTED BY SOME WEAK INSTABILITY BY THE RAP MODEL. HAVE
KEPT A CHANCE FOR SNOW SHOWERS ACRS THE FAR NORTH. POINTS FARTHER
SOUTH...THE BOUNDARY LAYER WILL BE WARM ENOUGH FOR A RAIN/SNOW
SHOWER MIX JUST NORTH OF I-70...WITH RAIN SHOWERS ALONG AND SOUTH
OF I-70. TEMPERATURES ARE EXPECTED TO BE WARMER OVER THE SOUTH WITH
MORE SUNSHINE. HAVE TEMPERATURES RANGING FROM THE MID 30S FAR
NORTH TO THE UPPER 40S SOUTH OF THE OHIO RIVER.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
LINGERED LIGHT CHANCES OF PRECIPITATION TONIGHT AS AMPLE LL
MOISTURE COULD CREATE SOME FLURRIES/LIGHT SNOW SHOWERS/LIGHT RAIN
SHOWERS. LINGERED CLOUDS IN NW FLOW AND CAA. BEFORE THE LOWER
LAYERS DRY OUT AND SOME CLEARING ON LATE THURSDAY/EARLY FRIDAY.
WHILE FCST AREA REMAINS UNDER QUIET RIDGING AND CAA...A DEEPENING
TROUGH FROM THE SOUTHERN PLAINS APPROACHES THE MID OHIO VALLEY BY
FRIDAY NIGHT INTO SATURDAY. EACH MODEL RUN OF THE GFS/ECMWF AND
ESPECIALLY THE NAM ARE QUICKER AND FURTHER NORTH WITH THE
PRECIPITATION ONSET. THERE IS POTENTIAL FOR ACCUMULATING SNOW IN
THE FAR SE FCST AREA WITH THIS SYSTEM...WORTH A MENTION IN THE
HAZARDOUS WEATHER OUTLOOKS...AND MAY YIELD ADVISORY LEVEL SNOWFALL
IN THE SOUTHEAST.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
MODELS ARE NOT IN AGREEMENT ON A SYSTEM THAT IS EXPECTED TO MOVE
THROUGH THE AREA SUNDAY INTO MONDAY. THE GFS KEEPS MOST OF THE
PRECIPITATION SOUTH OF THE AREA WITH THIS SYSTEM WHILE THE ECMWF
LINGERS PRECIPITATION ACROSS THE AREA THROUGH ALMOST THE ENTIRE
SUNDAY TO MONDAY TIME FRAME. WENT CLOSER TO THE ECMWF SOLUTION
HOWEVER KEPT PRECIPITATION CHANCES CONFINED TO THE CHANGE CATEGORY
FOR MOST LOCATIONS AT THIS TIME. TEMPERATURES WILL BE COOL ENOUGH
THAT ANY PRECIPITATION THAT DOES OCCUR SUNDAY INTO MONDAY WILL BE
IN THE FORM OF SNOW. AFTER THIS TIME HIGH PRESSURE WILL BUILD INTO
THE AREA FOR TUESDAY.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
THE MID LEVEL SHORT WAVE HAS PUSHED OFF TO THE EAST AND WITH
IT...THE MAIN AREA OF PCPN HAS SHIFTED NORTHEAST OF THE CENTRAL
OHIO TAF SITES. WITH THE LOW LEVEL FLOW BECOMING MORE
WESTERLY...MVFR TO OCCASIONALLY IFR CIGS HAVE BEEN SLOWLY WORKING
THEIR WAY EASTWARD OVER THE LAST FEW HOURS AND EXPECT THEM TO
REACH KCMH/KLCK WITHIN THE NEXT HOUR OR TWO. THE LOW LEVEL FLOW
WILL BACK AROUND TO THE SOUTHWEST THROUGH LATE MORNING/EARLY
AFTERNOON. AS THIS OCCURS...EXPECT TO SEE SOME IMPROVEMENT IN
CIGS...ESPECIALLY AT KCVG/KLUK.
A SECONDARY MID LEVEL SHORT WAVE WILL MOVE QUICKLY EAST ACROSS
THE AREA LATER THIS AFTERNOON. THIS WILL RESULT IN SOME SCATTERED
SHOWER ACTIVITY...ESPECIALLY AT THE NORTHERN TAF SITES. ON THE
BACK SIDE OF THIS SHORT WAVE...LOW LEVEL FLOW WILL BECOME
NORTHERLY AS WE HEAD INTO THIS EVENING. THIS WILL ALLOW FOR MVFR
CIGS TO SAG DOWN ACROSS THE AREA OVERNIGHT INTO THURSDAY MORNING.
OUTLOOK...MVFR CEILINGS VISIBILITIES POSSIBLE SUNDAY AFTERNOON.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...JDR
NEAR TERM...HICKMAN
SHORT TERM...JDR
LONG TERM...NOVAK
AVIATION...JGL
AREA FORECAST DISCUSSION
NWS TULSA OK
806 PM CST THU JAN 22 2015
.UPDATE...
POPS HAVE BEEN REDUCED IN THE SOUTH FOR TONIGHT. SEE DISCUSSION BELOW...
&&
.DISCUSSION...
THE LATEST SHORT RANGE DATA...INCLUDING THE HRRR AND RAP...SUGGEST
PRECIP SHOULD REMAIN TO OUR SOUTH AND EAST TONIGHT. THE WARM
CONVEYOR PRECIP HAS SHIFTED EAST...AND THE MAIN UPPER SYSTEM IS
STILL OUT AROUND THE BIG BEND REGION AND IS NOT GAINING ANY
LATITUDE. HAVE THUS PULLED BACK ON PRECIP CHANCES TONIGHT. THE 18Z
GFS IS THE ONLY SOLUTION THAT HAS PRECIP NORTH OF THE RED
RIVER...SO I HAVE LEFT SLIGHT CHANCES OR LOW END CHANCE POPS IN
THE FAR SOUTHEAST.
LACY
&&
.PREV DISCUSSION... /ISSUED 516 PM CST THU JAN 22 2015/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. CEILINGS
IN THE 5-10 THOUSAND FEET RANGE WILL PREVAIL THROUGH TONIGHT
ACROSS SE OK AND WC AR.
PREV DISCUSSION... /ISSUED 300 PM CST THU JAN 22 2015/
DISCUSSION...
A LONGWAVE UPPER TROUGH WILL TRAVERSE THE SOUTHERN PLAINS OVERNIGHT
TONIGHT. RELATED PRECIPITATION IS EXPECTED TO REMAIN CONFINED TO FAR
SOUTHEAST OKLAHOMA AND WEST CENTRAL ARKANSAS. WITH TEMPERATURES
ACROSS THIS AREA FALLING FROM NEAR 40 THIS AFTERNOON TO THE LOW TO
MID 30S TONIGHT... SOME SNOWFALL WILL BE POSSIBLE... MAINLY AFTER
MIDNIGHT. LITTLE IF ANY ACCUMULATION IS EXPECTED. ALL PRECIPITATION
CHANCES WILL END BY MID MORNING FRIDAY AS THE UPPER TROUGH CONTINUES
EASTWARD.
ANOTHER SUSTAINED WARMING TREND WILL BEGIN SATURDAY... LASTING
THROUGH AT LEAST THURSDAY. DAILY MAX AND MIN TEMPERATURES WILL
EVENTUALLY RUN 10 TO 15 DEGREES ABOVE SEASONAL AVERAGES AS UPPER
RIDGING BUILDS ACROSS THE SOUTHERN PLAINS DURING THE UPCOMING WEEK.
FROM SUNDAY ON... AFTERNOON HIGHS IN THE 60S WILL BE COMMON ACROSS
THE FORECAST AREA... WITH SOME 70S POSSIBLE BY MID WEEK. OVERNIGHT
LOWS ARE EXPECTED TO REMAIN ABOVE FREEZING AREAWIDE... WHILE SLOWLY
INCREASING DURING THE MIDDLE OF THE WEEK. PRECIPITATION CHANCES WILL
BE MINIMAL THROUGHOUT THE NEXT 7 DAYS OR SO.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 29 49 31 57 / 0 0 0 0
FSM 35 48 29 54 / 10 10 0 0
MLC 33 48 29 56 / 10 10 0 0
BVO 25 49 27 56 / 0 0 0 0
FYV 30 45 26 51 / 0 0 0 0
BYV 29 45 28 50 / 0 0 0 0
MKO 33 47 30 55 / 0 0 0 0
MIO 27 47 29 52 / 0 0 0 0
F10 32 48 31 56 / 0 0 0 0
HHW 36 49 29 57 / 20 20 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
LONG TERM....30
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
953 PM EST THU JAN 22 2015
.SYNOPSIS...
A DEVELOPING AREA OF LOW PRESSURE WILL TRACK ALONG THE GULF AND
SOUTH ATLANTIC COASTS THROUGH FRIDAY NIGHT...BEFORE MOVING UP THE
EAST COAST OVER THE WEEKEND. THE LOW WILL BRING WIDESPREAD
PRECIPITATION OVER OUR AREA FRIDAY INTO SATURDAY. HIGH PRESSURE WILL
BRIEFLY BUILD IN ON SUNDAY...BEFORE A COLDER LOW PRESSURE SYSTEM
AFFECTS THE FORECAST AREA SUNDAY NIGHT THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 945 PM EST...THE LEADING EDGE OF LIGHT PRECIPITATION FALLING
FROM MID LEVEL CLOUD BASES IS APPROACHING THE CWFA FROM THE SW LATE
THIS EVENING...AND THE ONSET OF POP HAS BEEN ACCELERATED FOR THE
NIGHTTIME HOURS. NO CHANGES WILL BE MADE TO THE ADVISORY AREA SINCE
THE LATEST RAP AND INCOMING 00Z NAM PROFILES LOOK VERY SIMILAR TO
THE PREVIOUS MODEL RUNS.
OTHERWISE...WATER VAPOR IMAGERY CONTINUES TO SHOW THE MAIN DRIVING
UPPER LOW MOVING INTO W TX LATE THIS EVENING...WITH SFC DEVELOPMENT
CONTINUING ALONG THE WRN GULF COAST AHEAD OF THIS FEATURE. DEEPER
LAYER MOISTURE AND RAPIDLY INCREASING ISENTROPIC LIFT WILL START
SPREADING INTO THE EXTREME SW SECTIONS 09Z TO 12Z...SPREADING
CATEGORICAL LIGHT TO MODERATE PRECIPITATION COVERAGE ACROSS THE
REGION THROUGH MIDDAY. MEANWHILE...1030 MB SFC HIGH PRES CONTINUES
TO LAY OVER TO THE N OF THE AREA...WITH CHILLY LOW LEVEL
THICKNESSES AND DRIER AIR PARKED ACROSS WRN NC. MODEL PROFILES FROM
ASHEVILLE TO W OF HICKORY TO NEAR BOONE SUPPORT SNOW AT ONSET
OVERNIGHT...WITH WET BULB PROFILES ISOTHERMAL NEAR ZERO. SOME DEGREE
OF WARM NOSING IS EXPECTED TO DEVELOP FRI MORNING...WITH A STEADY
TRANSITION TO SLEET THROUGH MID MORNING AND THEN BRIEF FREEZING RAIN
LINGERING ACROSS THE NRN BLUE RIDGE INTO THE AFTERNOON. PROFILES
SUPPORT MAINLY LIQUID ACROSS SC...NE GA...AND THE NC
PIEDMONT...ALTHOUGH BRIEF SLEET AT THE ONSET WILL BE POSSIBLE JUST
ABOUT ANYWHERE.
THE TRANSIENT NATURE OF THE WINTRY PTYPES ACROSS THE NC MTNS WILL
LIKELY WORK TO KEEP ANY ONE PTYPE FROM REACHING WARNING CRITERIA.
THE CURRENT ADVISORY SUITE REMAINS WELL PLACED...WITH LIGHT SNOW AND
ICE ACCUMULATIONS FRI...WITH A TRANSITION TO ADDITIONAL LIGHT NW
FLOW SNOW ACCUMULATIONS INTO FRI NIGHT. WILL KEEP TEMPS NEAR RAW
MODEL VALUES...WITH A BRIEFLY GUSTY NE FLOW POSSIBLE EAST OF THE
MTNS AS A BARRIER JET FORMS DESPITE THE WEAK DAMMING HIGH POSITION.
PRECIP RATES WILL LIKELY START TO SLACKEN FROM THE SW VERY LATE IN
THE DAY AS WEAK MID LEVEL DRYING BEGINS TO WORK BACK IN.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 230 PM THURSDAY...THE SHORT TERM PICKS UP AT 00Z
SATURDAY...WITH MODELS IN GOOD AGREEMENT ON THE SFC LOW CENTERED
INVOF TALLAHASSEE FL...WITH A SHARP H5 TROF AXIS ACRS THE LWR MS
VALLEY. FRIDAY EVENING LOOKS LIKE A CONTINUED TRANSITION TO ALMOST
ALL RAIN ACRS THE CWFA...AS LLVL FLOW TURNS FROM SE TO SW...AND A
DRY SLOT PUNCHES INTO THE SRN APPALACHIANS FROM THE SW. TEMPS MAY BE
ABLE TO HOLD AROUND 30-32 ALONG THE ERN SLOPES OF THE NRN NC BLUE
RIDGE. HOWEVER...ADDITIONAL ICE ACCUMS SHUD BE VERY LIGHT...WITHIN A
LULL IN PRECIP. BY 12Z SAT...A DEFORMATION ZONE WITHIN THE MID LVL
TROF WILL ENTER THE NC MTNS...BRINGING FALLING MID LVL HEIGHTS (AND
SNOW LEVELS)...WHILE INCREASING THE POP. TAKING A BLEND OF THE
NAM/SREF WITH THE WPC QPF (THROWING OUT THE GFS)...I GET 1-2" OF
ADDITIONAL SNOW ACCUM MAINLY ABOVE 3500 FT SATURDAY MORNING. THE
DEFORMATION ZONE WILL TRANSLATE EAST QUICKLY...WITH POPS TAPERING
OFF BY MIDDAY. BY SATURDAY AFTN...NWLY 850 MB FLOW WILL
INCREASE...KEEPING A SLGT CHC TO LOW-END CHC OF SNOW SHWRS ALONG THE
TN/NC BORDER. GRADUAL CLEARING IS EXPECTED EAST OF THE MTNS. TEMPS
WILL HOVER IN THE 30S ACRS THE AREA FRIDAY NIGHT TO NEAR 40 IN THE
UPR SAVANNAH VALLEY...THEN WARM LITTLE ABOVE 3500 FT...BUT INTO THE
MID-UPR 40S ACRS THE PIEDMONT ON SATURDAY.
SATURDAY NIGHT AND SUNDAY...A BROAD H5 TROF WILL LINGER IN WAKE OF
THE SATURDAY TROF PASSAGE. THE CWFA WILL BE IN BETWEEN A NOREASTER
AFFECTING THE MID ATLANTIC/NEW ENGLAND...AND A CLIPPER THAT WILL BE
DIVING INTO THE WRN GREAT LAKES. ANOTHER VORT MAX WILL CROSS THE NC
MTNS SATURDAY NIGHT WITHIN THE LONGWAVE TROF. IT WILL HAVE LITTLE
MOISTURE TO WORK WITH...BUT THE NAM AND GFS BOTH SHOW A HUNDREDTH OR
TWO OF QPF RESPONSE ALONG THE TN/NC NWLY FLOW UPSLOPE AREAS. I
BUMPED UP POPS BACK TO CHC SATURDAY NIGHT FROM MADISON TO AVERY
COUNTY FOR SNOW SHWRS. LITTLE OR NO ACCUMS ARE EXPECTED. THE LLVL
FLOW WILL BACK TO W-SWLY ON SUNDAY...AND GUIDANCE IN GOOD AGREEMENT
ON A DRY DAY ACRS THE CWFA AHEAD OF THE APPROACHING CLIPPER SYSTEM.
TAKING A MODEL BLEND...I GET NEAR NORMAL TEMPS UNDER PARTLY CLOUDY
SKIES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 200 PM THU...LONGWAVE TROUGH PERSISTS OVER THE ERN CONUS THRU
THE MOST OF THE MEDIUM RANGE. THE UPPER PATTERN IS INITIALLY LOCKED
IN PLACE BY A REX BLOCK OVER THE WEST COAST...WHICH BREAKS DOWN
MONDAY. GLOBAL MODELS DIFFER IN HOW THE PATTERN SUBSEQUENTLY EVOLVES
OVER THE WEST BUT AGREE RIDGING WILL OCCUR OVER THE EAST BY WED
NIGHT. WHILE THE ERN TROUGH REMAINS IN PLACE...A SERIES OF CLIPPER-
LIKE SHORTWAVES WILL MOVE ACROSS OUR AREA. MEAN NWLY FLOW WILL
CONTINUE...SUGGESTING A CONTINUED FOCUS FOR PRECIP CHANCES ALONG THE
WRN FACING SLOPES OF THE NC MTNS. THE PASSING SHORTWAVES APPEAR
CAPABLE OF FORCING VERY LIGHT PRECIP OVER THE PIEDMONT...MAINLY THE
NC SIDE. DOWNSLOPING WILL BE WORKING AGAINST SAID FORCING AND ONLY
LOW POPS AND QPF WILL BE ADVERTISED THERE. IN THE MTNS...BLENDED QPF
FROM THE GLOBAL MODELS AND AN EXPECTATION OF PREDOMINANTLY SNOW AS A
PTYPE SUGGEST TOTALS GENERALLY 1-2 INCHES IN THE 12 HR PERIODS
SUNDAY NIGHT AND MONDAY. THIS MAY WARRANT A WINTER WX ADVY.
THE 22/12Z GFS CONTINUES TO EXHIBIT A COUPLE OF KEY DIFFERENCES FROM
THE CORRESPONDING GEM OR EC. THE FIRST IS IN THE WELL DEFINED
SHORTWAVE CROSSING THE AREA MONDAY...WHICH DOES NOT COME AS FAR SOUTH
ON THE GFS PROGS AND IS FOLLOWED BY A SECONDARY CHANNELED AREA OF
VORT. THE EC DEPICTS A MORE BROAD TROUGH WITH DISTINCT EDDIES DARTING
THROUGH WITHIN. THE EC BRINGS ANOTHER WAVE OF LIGHT QPF INTO THE AREA
TUESDAY AS A RESULT...WHEN TEMPS HAVE COOLED TO BECOME A LITTLE MORE
SUPPORTIVE OF WINTRY PRECIP. THE GEM LOOKS MORE LIKE THE EC THAN THE
GFS BUT DOES NOT RESPOND WITH QPF TUE. RUN-TO-RUN CONSISTENCY IS NOT
THAT GREAT FOR ANY OF THE MODELS WITH THE SMALLER SCALE WAVES AND
ASSOCIATED QPF. WITH THIS PACKAGE THE PIEDMONT POPS HAVE BEEN
EXPANDED SLIGHTLY THRU EARLY TUE ON ACCOUNT OF CONTINUED HINTS AT
PRECIP.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
AT KCLT...ANTICIPATE LOWERING VFR CIGS OVERNIGHT AHEAD OF THE
APPROACHING GULF COAST LOW PRESSURE SYSTEM. LIGHT RAIN WILL SPREAD
IN FROM THE SOUTHWEST ON THE STRENGTH OF EARLY UPGLIDE 12Z TO
14Z...WITH CIGS LIKELY REACHING MVFR LEVELS AT THAT TIME. SOME SLEET
COULD EASILY MIX IN RIGHT AT ONSET...BUT WITH ALL LIQUID PTYPES
SETTING UP VERY QUICKLY THEREAFTER. ANTICIPATE THE DEEPEST MOISTURE
AND FORCING PRODUCING MODERATE RAINFALL THROUGH FRI
AFTERNOON...ALONG WITH SOLID IFR CONDITIONS DEVELOPING. WINDS WILL
BECOME ENE TO NE THIS EVENING AND STEADILY STRENGTHEN THROUGH FRI.
ELSEWHERE...PRECIPITATION WILL SPREAD IN FAIRLY RAPIDLY FROM THE
SOUTHWEST 10Z TO 13Z FRIDAY...WITH VFR CIGS QUICKLY DIPPING TO MVFR
THROUGH MID MORNING. MORE SOLID IFR CONDITIONS WILL THEN DEVELOP
THROUGH FRIDAY...WITH MAINLY RAIN AT THE UPSTATE TAF SITES...SNOW
AND SLEET CHANGING TO RAIN AT KAVL...AND BRIEF ONSET SLEET AT KHKY
BECOMING ALL RAIN THROUGH THE DAY. EXPECT STRENGTHENING NE
FLOW...EXCEPT NW WINDS AT KAVL EARLY TURNING SE THROUGH FRI. SOME
BRIEF ONSET SLEET CANNOT BE RULED OUT AT THE SC TAF SITES AS
WELL...BUT RAIN SHOULD BE PREDOMINANT.
OUTLOOK...PRECIPITATION AND RESTRICTIONS CONTINUE FRIDAY NIGHT
BEFORE DIMINISHING FROM THE SW ON SAT. ANOTHER SYSTEM ARRIVING SUN
NIGHT INTO MONDAY COULD BRING MORE RESTRICTIONS OVER THE
MTNS...MAINLY NEAR THE TN BORDER THROUGH MONDAY NIGHT.
CONFIDENCE TABLE...
03-09Z 09-15Z 15-21Z 21-00Z
KCLT HIGH 100% HIGH 100% MED 68% MED 70%
KGSP HIGH 100% HIGH 100% MED 77% HIGH 90%
KAVL HIGH 100% HIGH 100% MED 79% HIGH 86%
KHKY HIGH 100% HIGH 100% MED 73% HIGH 83%
KGMU HIGH 100% HIGH 100% MED 75% HIGH 90%
KAND HIGH 100% HIGH 98% HIGH 88% HIGH 90%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WINTER WEATHER ADVISORY FROM 6 AM FRIDAY TO NOON EST SATURDAY
FOR NCZ033-048>052-058-059-062>064-501-503-505.
SC...NONE.
&&
$$
SYNOPSIS...WIMBERLEY
NEAR TERM...HG
SHORT TERM...ARK
LONG TERM...WIMBERLEY
AVIATION...HG
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
843 PM CST THU JAN 22 2015
.UPDATE...
LATEST SURFACE OBSERVATIONS SHOW TEMPERATURES IN THE UPPER 30S TO
AROUND 40 ACROSS THE FORECAST AREA WITH DEWPOINTS IN THE MID 20S
TO LOWER 30S. THESE TEMPS ARE ALREADY AT FORECAST LOWS ACROSS THE
SOUTH...AND HAVE GONE AHEAD AND LOWERED MINS FOR TONIGHT AREAWIDE
CLOSER TO OUR SUPERMODEL BLEND. RADAR IMAGERY SHOWS LIGHT TO
MODERATE RAIN CONTINUES JUST TO OUR SOUTH ACROSS NORTHERN
MS/AL...AND THERE HAVE BEEN SEVERAL REPORTS OF SLEET MIXING IN
WITH THE RAIN AT TIMES WHERE PRECIP HAS BEEN HEAVIER. BASED ON
THESE REPORTS ALONG WITH HRRR AND A LOOK AT LATEST FORECAST
SOUNDINGS...WILL ADD A CHANCE OF SLEET TO ZONES FOR TONIGHT AS
DRY AIR IN THE LOWER TROPOSPHERE MAY ALLOW FOR BRIEF PERIODS OF
SLEET...ESPECIALLY ACROSS THE COOLER NORTHERN ZONES. NO SLEET
ACCUM IS EXPECTED DUE TO ABOVE FREEZING TEMPS. THERMO PROFILES IN
THE NORTHWEST MID STATE ARE VERY CLOSE TO BEING A RAIN/SNOW MIX
FOR A BRIEF TIME FRIDAY MORNING PER 00Z NAM...BUT EXPECTED LIGHT
NATURE OF PRECIP SHOULD KEEP EVERYTHING RAIN/POSSIBLE SLEET.
REST OF FORECAST FOR THE FRIDAY/FRIDAY NIGHT PERIOD REMAINS
GENERALLY ON TRACK...WITH RAIN CONTINUING AREAWIDE INTO THE
AFTERNOON BEFORE A BRIEF LULL IN PRECIPITATION. MORE RAIN THEN
MOVES IN FRIDAY EVENING AS UPPER TROUGH AXIS MOVES ACROSS...WITH
CAA ALOFT ALLOWING FOR THE RAIN TO MIX WITH AND EVENTUALLY
CHANGEOVER TO SNOW FRIDAY NIGHT BEFORE ENDING SATURDAY MORNING. A
LOOK AT LATEST COBB SNOW TOTALS FOR THE NAM AND GFS CONTINUE TO
SUGGEST A DUSTING TO HALF INCH OF SNOW POSSIBLE FOR MUCH OF THE
MID STATE FRIDAY NIGHT...WITH HIGHEST AMOUNTS IN THE HIGHER
ELEVATIONS OF THE HIGHLAND RIM AND ON THE CUMBERLAND PLATEAU. ANY
SNOW WOULD MAINLY ACCUMULATE ON GRASSY AREAS AND ELEVATED SURFACES
DUE TO THE LOW SNOW RATIOS EXPECTED AND TEMPERATURES REMAINING
NEAR/ABOVE FREEZING...SO NO SIGNIFICANT IMPACTS TO TRAVEL ARE
ANTICIPATED WITH THIS EVENT. ANY SNOW THAT CAN ACCUMULATE WILL
MELT QUICKLY SATURDAY MORNING AS TEMPERATURES WARM WELL INTO THE
40S.
SHAMBURGER
&&
.PREV DISCUSSION... /ISSUED 537 PM CST THU JAN 22 2015/
UPDATE...
00Z AVIATION UPDATE.
AVIATION...
VFR CONDITIONS SHOULD START DECREASING OVERNIGHT AS LOWER CEILINGS
AND CHANCES FOR RAIN MOVE IN FROM THE SOUTH. BY LATE MORNING
TOMORROW...KCKV AND KBNA MAY SEE IFR CEILINGS WITH THE RAINFALL.
KCSV WILL LIKELY SEE IFR CEILINGS WITH LIFR POSSIBLE RIGHT BEFORE
NOON. LOWER CEILINGS AND CHANCES FOR RAIN SHOULD CONTINUE UNTIL
THE END OF THIS TAF PERIOD.
PREV DISCUSSION... /ISSUED 330 PM CST THU JAN 22 2015/
DISCUSSION...
SFC CONTINUES TO DEVELOP OFF OF THE TX GULF COAST. MOISTURE IN THE
FORM OF RAINFALL EXTENDS NORTH AND EAST OF THE LOW WITH THE LEADING
EDGE OF THE PRECIP AS FAR AS MS AND NRN AL. SFC HIGH PRESSURE RIDGE
STRETCHES ACROSS THE CENTRAL PLAINS AND IS PROVIDING A NORTHERLY
FLOW INTO THIS GULF SYSTEM. THE SFC HIGH IS NOT ALL THAT STRONG SO
THE BULK OF THE PRECIPITATION THROUGH TOMORROW WILL BE RAIN.
THE SFC LOW WILL DEVELOP SOME DEGREE OF TROUGH INVERSION AS IT
MOVES EAST. THE AXIS WILL TAKE A SW-NE ORIENTATION AND SO ANY WARMUP
WILL BE CONFINED TO AREAS ACROSS THE DEEP SOUTH.
CLOSER TO HOME...WE WILL SEE RAINFALL SPREAD NORTHWARD AND REACH
OUR SOUTHERN BORDER AROUND MIDNIGHT AND WILL THEN BE CLOSE TO
OVERSPREADING THE ENTIRE MID STATE BY 12Z FRIDAY. DURING THE DAY
FRIDAY...CLOSED 850 MB LOW WILL TRACK DIRECTLY OVER THE MID STATE
AND BRING WITH IT CATEGORICAL CHANCES FOR RAINFALL. ON FRIDAY
EVENING...THE ASSOCIATED UPPER LEVEL SYSTEM WILL BE WORKING ACROSS
THE AREA. WITHIN THE UPPER LEVELS HOWEVER...THE SYSTEM WILL TAKE THE
FORM OF AN OPEN WAVE...ALTHOUGH SOME DEEPENING IS INDICATED AS THE
AXIS CROSSES OUR PLATEAU.
AS FOR PRECIP TYPE...GIVEN THAT THE UPPER SYSTEM IS NOT CLOSED OFF
AND STRONGER...LITTLE IN THE WAY OF SURPRISES...IN TERMS OF
EXPECTED FREEZING LEVELS...IS EXPECTED. HAVING SAID THAT...THE
RAIN TO SNOW TRANSITION LOOKS AS THOUGH IT WILL OCCUR IN OUR
NORTHWEST BETWEEN 3Z AND 6Z. THIS IS BASED ON BOTH THE GFS AND NAM
EXPECTED FREEZING LEVELS. THE TRANSITION OVER TO SNOW WILL
CONTINUE OVERNIGHT FRIDAY AND BY 9Z...I WILL INCLUDE AT LEAST A
CHANCES OF A RAIN AND SNOW MIX OVER THE ENTIRE MID STATE. LOW
TEMPS WILL DROP TO NEAR FREEZING SOUTH AND A FEW DEGREES BELOW
THAT ACROSS THE NORTH. SNOW ACCUM WILL BE INCLUDED BUT AMOUNTS
LOOK LIGHT WITH A DUSTING TO LESS THAN A HALF INCH WEST OF THE
PLATEAU AND PERHAPS A HALF INCH ALONG THE PLATEAU. AFTER A LIGHT
SNOW SHOWER OR TWO ON SATURDAY MORNING...THE SYSTEM WILL EXIT TO
THE EAST.
FOR THE NEAR TERM TEMPS...WILL LEAN TOWARD THE MAV GUIDANCE.
IN THE EXT FCST...CLIPPER SYSTEM WILL MOVE QUICKLY ACROSS THE UPPER
MIDWEST. THIS FEATURE WILL DRAG A FRONTAL SYSTEM ACROSS THE AREA ON
SUNDAY NIGHT. AHEAD AND BEHIND THIS FEATURE...A CHANCE OF SHOWERS
WILL BE INCLUDED. AGAIN...ENOUGH COLD AIR WILL WORK INTO THE POST
FRONTAL SECTOR SO AS TO INCLUDE A CHANCE OF RAIN AND SNOW FOR MONDAY
AFTERNOON AS THE SYSTEM EXITS.
TUES THROUGH THURS WILL FEATURE A DEEPENING TROUGH ALONG THE
ATLANTIC COAST. THIS TRANSLATES TO AN INCREASE IN HEIGHTS OVER TN BY
THURS. THEREFORE...IN COMBINATION WITH DRY WEATHER...LOOK FOR TEMPS
TO RUN A FEW DEGREES ABOVE NORMAL.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
55
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
842 PM CST THU JAN 22 2015
.DISCUSSION...AREAS OF LIGHT TO MODERATE RAINFALL HAVE DEVELOPED
IN THE PAST HOUR NEAR THE SOUTHERN COASTAL COUNTIES. HRRR 4 KM HAS
BEEN FLUCTUATING A BIT WITH RAIN OVER THE AREA FROM THE LAST
COUPLE OF RUNS. LATEST RUN IS SHOWING SOME RAIN CONTINUING INTO
THE OVERNIGHT HOURS. THUS...AM GOING TO KEEP THE CHANCE POPS GOING
FOR TONIGHT. HOWEVER...AM GOING TO LOWER THEM JUST A TAD OVER THE
VICTORIA AREA TO 40 POPS. OTHERWISE...GFE FORECAST MONITOR IS
SHOWING TEMPERATURES AND DEW POINTS MUCH IN LINE WITH CURRENT
FORECAST (GREEN). AS A RESULT...WILL KEEP ON-GOING FORECAST GOING
CONCERNING TEMPS/WINDS/DEW POINTS SINCE FORECAST OVERALL IS IN
REALLY GOOD SHAPE.
&&
.MARINE...SCA SEEMS TO BE WORKING FINE. WILL LOWER POPS JUST A BIT
OVER THE GULF WATERS...AS EXPECT AREAS OF RAIN TO MAINLY STAY
INLAND. STILL CHANCE POPS FOR THE NEARSHORE AND BAYS. SEAS ALREADY
NEAR 10 FEET AT BOY019...AS IT SHOWS IN FORECAST. THUS...NO
OTHER CHANGES NEEDED AT THIS TIME BESIDES THE SLIGHT POP ADJUSTMENT.
&&
.PREV DISCUSSION... /ISSUED 521 PM CST THU JAN 22 2015/
DISCUSSION...SEE AVIATION DISCUSSION BELOW FOR THE 00Z TAFS.
AVIATION...MVFR CONDITIONS ARE EXPECTED TO PREVAIL OVERNIGHT
ALONG WITH ADDITIONAL -RA AS AN UPPER LEVEL LOW SWINGS ACROSS TX.
CONDITIONS ARE FCST TO IMPROVE AROUND MID MORNING FRI AS THE UPPER
LOW EXITS THE REGION AND DRIER AIR BEGINS TO FILTER INTO S TX. LRD
IS EXPECTED TO IMPROVE TO VFR INITIALLY THEN IMPROVING CONDITIONS
WILL SPREAD EAST THROUGH THE DAY.
PREV DISCUSSION... /ISSUED 253 PM CST THU JAN 22 2015/
SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...COLD FRONT HAS
PUSHED OFF THE MIDDLE TEXAS COAST WITH A COLD AIRMASS ALREADY
SETTLED INTO THE REGION WITH COLD AIR ADVECTION CONTINUING THROUGH
THE NIGHT AS BREEZY/WINDY NORTHERLY WINDS PERSIST. AREAS OF LIGHT
RAIN CONTINUE TO DRIFT ACROSS INLAND AREAS AS OF MID AFTERNOON BUT
SHOULD GRADUALLY DISSIPATE EARLY THIS EVENING. ADDITIONAL RAIN
/MAINLY LIGHT/ IS PROG TO DEVELOP OVERNIGHT AS MUCH OF THE CWA
BECOMES PLACED IN THE RRQ OF A 110KT H25 JET STREAK AND A MID
LEVEL TROUGH AXIS APPROACHES THE REGION. RAIN CHANCES WILL
DECREASE EARLY FRIDAY AS MID LEVEL TROUGH BEGINS TO SHIFT EAST AND
LLVL MOISTURE DECREASES. GRADUAL CLEARING MAY OCCUR FROM NW TO SE
TOMORROW AFTERNOON...BUT OVERALL AM EXPECTING A MOSTLY CLOUDY DAY.
CONTINUED COLD AIR ADVECTION AND CLOUD COVER WILL KEEP DAYTIME
TEMPS WELL BELOW NORMAL WITH SOME LOCATIONS ACROSS NE ZONES
STRUGGLING TO GET OUT OF THE 40S. SURFACE RIDGE AXIS EXTENDS INTO
S TX FRIDAY NIGHT RESULTING IN DRY LOW LEVEL AIRMASS AND LIGHT
WINDS...ALLOWING FOR STRONG RADIATIONAL COOLING WITH TEMPS
AREAWIDE LIKELY TO FALL INTO THE 30S.
LONG TERM...(SATURDAY THROUGH THURSDAY)...TROUGH AXIS WILL BE EAST
OF THE AREA ON SATURDAY...WITH DRIER AIR FILTERING INTO SOUTH TEXAS.
WINDS WILL ALSO BE RELAXING AS PRESSURE GRADIENT WEAKENS. COOLEST
DAY OF THE EXTENDED WILL SATURDAY BEHIND DEPARTING TROUGH. HIGHS
WILL ONLY BE IN THE LOWER/MIDDLE 60S. WARMING TREND WILL THEN
COMMENCE ON SUNDAY. UPPER LEVEL RIDGE WILL REMAIN THE MAIN WEATHER
FEATURE ACROSS SOUTH TEXAS FOR THE UPCOMING WEEK. THIS WILL LEAD TO
QUIET WEATHER OVER THE AREA AND TEMPERATURES ABOVE NORMAL FOR THE
END OF JANUARY. HIGHS WILL GENERALLY BE IN THE LOWER TO MIDDLE 70S
OVER INLAND LOCATIONS...WITH MID/UPPER 60S ALONG THE IMMEDIATE
COAST.
MARINE...AS OF MID AFTERNOON A COLD FRONT WAS MOVING EAST ACROSS
THE OFFSHORE WATERS WITH A STRONG OFFSHORE FLOW AND HAZARDOUS
SEAS DEVELOPING IN ITS WAKE. SMALL CRAFT ADVISORIES ARE IN EFFECT
FOR ALL MARINE AREAS TONIGHT INTO FRIDAY. CONDITIONS WILL
GRADUALLY IMPROVE FRIDAY NIGHT WITH PLEASANT MARINE CONDITIONS
CURRENTLY EXPECTED OVER THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 45 52 34 64 43 / 40 20 10 0 10
VICTORIA 43 50 34 62 39 / 50 30 10 0 10
LAREDO 43 55 37 65 42 / 30 10 0 0 0
ALICE 44 53 35 65 41 / 40 20 0 0 10
ROCKPORT 45 53 39 62 45 / 50 20 10 0 10
COTULLA 42 56 34 64 41 / 40 20 0 0 0
KINGSVILLE 45 54 35 66 42 / 40 20 0 0 10
NAVY CORPUS 46 52 38 62 47 / 40 20 10 0 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST FRIDAY NIGHT FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT
ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY
TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS
TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL NOON CST FRIDAY FOR THE FOLLOWING
ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT ARANSAS...
BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT O`CONNOR.
&&
$$
GW/86...SHORT TERM
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
727 PM CST THU JAN 22 2015
.UPDATE...
WE HAVE EXPANDED THE WINTER WEATHER ADVISORY INTO THE CENTRAL AND
EASTERN SOUTH PLAINS THIS EVENING BASED ON RADAR TRENDS. SHORT
TERM SOLUTIONS HAVE NOT PICKED UP ON THIS EVENINGS SNOWFALL VERY
WELL. TRENDS SUGGEST PERHAPS ANOTHER 1/2 INCH WITH OUTSIDE CHANCE
FOR ANOTHER INCH. TEMPERATURES WILL BE FALLING INTO THE UPPER 20S
WHICH LIKELY WILL LEAD TO INCREASING ICING ON HIGHWAYS. ADVISORY
ENDS CURRENTLY AT MIDNIGHT. RMCQUEEN
&&
.PREV DISCUSSION... /ISSUED 557 PM CST THU JAN 22 2015/
AVIATION...
WE HAVE LIKELY SEEN THE LAST OF THE LIFR FOR THIS EVENT.
CEILINGS AT KPLV ARE CURRENTLY IN THE IFR RANGE AND ARE FORECASTED
TO IMPROVE AFTER 03Z. OTHERWISE EXPECT CURRENT MVFR CIGS TO GIVE
WAY TO VFR AFTER MIDNIGHT AS THE SYSTEM AND THE LIGHT SNOW
ASSOCIATED WITH THE UPPER LEVEL LOW EXITS SOUTH AND EAST. WINDS
WILL BE LIGHT OVERNIGHT AND MAINTAIN THEIR NORTHERLY COMPONENT
BEFORE BACKING TOWARD THE WEST LATE FRIDAY MORNING.
PREV DISCUSSION... /ISSUED 306 PM CST THU JAN 22 2015/
SHORT TERM...
WATER VAPOR IMAGERY SHOWING A VIGOROUS STORM SYSTEM CONTINUING TO
MOVE SEWD THROUGH SRN NEW MEXICO. THE POSITIVELY TILTED TROUGH THAT
EXTENDS NEWD FROM THE BASE OF THE TROUGH /FROM SRN NEW MEXICO
THROUGH THE TEXAS PANHANDLE/ PRODUCING THE LAST BIT OF LIFT
ACROSS THE WRN AND CNTL PARTS OF THE FCST AREA. 18Z WRF-NAM AND
MORNING RUNS OF THE HRRR IN PRETTY GOOD AGREEMENT IN SHIFTING
LIGHT TO OCCASIONALLY MODERATE SNOWFALL SEWD IN TIME. SOME MODEST
ACCUMULATIONS GENERALLY LESS THAN 1/2 INCH REMAIN POSSIBLE WITH
THE HEAVIEST SNOW...BUT IT WILL BE MOVING INTO AN AREA THAT HAS
BEEN AT OR ABOVE FREEZING THIS AFTN. DO NOT ANTICIPATE ANY
PROBLEMS ASSOCIATED WITH THE SNOWFALL FROM LUBBOCK TO THE EAST AND
SOUTHEAST...SO CURRENT CONFIGURATION OF THE WINTER WEATHER
ADVISORY SHOULD SUFFICE.
PRECIP LIKELY TO COME TO AN END BY MIDNIGHT WITH POSSIBLE EXCEPTION
OF THE FAR SRN PART OF THE FCST AREA WHERE WILL KEEP SLIGHT CHC TO
LOW END CHANCE MENTION ATTM.
SOME CLEARING EXPECTED FROM NW TO SE BY SUNRISE. THAT CLEARING
ACROSS THE NWRN ZONES COMBINED WITH SNOW COVER SHOULD ALLOW TEMPS
THERE TO DROP TO OR BELOW COLD END OF MOS GUIDANCE WHILE FARTHER
EAST LOW TEMPS NEAR A MOS BLEND MORE LIKELY. HIGH TEMPS FRIDAY
WILL BE TRICKY. INSOLATION AND MODEST WEST WIND TO BE COUNTERACTED
ACROSS THE NWRN THIRD OF THE FCST AREA BY THE SNOW FIELD. WILL
CONTINUE TO UNDERCUT GUIDANCE THERE AND LEAN CLOSER TO MOS FURTHER
TO THE EAST AND SOUTHEAST.
LONG TERM...
NORTHWEST FLOW WILL MOVE OVERHEAD FOR THE WEEKEND INTO NEXT WEEK
LEADING TO DRY CONDITIONS AND A STEADY WARMUP UNDERNEATH INCREASING
HEIGHTS/THICKNESSES ALOFT WITH RIDGING DOMINATING THE WESTERN CONUS
AND TROUGHING ENCOMPASSING POINTS EAST. ASIDE FROM SOME SCATTERED
CIRRUS SATURDAY...OWING TO ENERGY ALOFT BEING SHUNTED SOUTHWEST
TOWARD THE GULF OF CALIFORNIA WITH DEVELOPMENT OF A CUTOFF
LOW...MOSTLY SUNNY SKIES WILL BE IN THE OFFING. TEMPERATURES SHOULD
GRADUALLY WARM INTO THE 40S/50S SATURDAY AND NEAR 50 IN VICINITY OF
LINGERING SNOWPACK IN THE FAR SOUTHWEST PANHANDLE TO MID 60S IN THE
ROLLING PLAINS SUNDAY. A BACKDOOR FRONT MAY BRING A NORTHERLY WIND
SHIFT BY MONDAY AS A DISTURBANCE DIVES ACROSS THE UPPER
MIDWEST/GREAT LAKES INTO THE OHIO VALLEY...BUT NO CHANGE IN AIRMASS
LOOKS TO BE IN STORE LOCALLY. FURTHER WARMING WELL INTO THE 60S
SHOULD OCCUR THROUGH THE WEEK AS UPPER RIDGING APPROACHES FROM THE
WEST. MAY SEE A COOLDOWN BACK TO NEAR AVERAGE BY MID-LATE WEEK IF
PACIFIC MOISTURE CAN ADVECT NORTHEAST AHEAD OF A SERIES OF PROGGED
DISTURBANCES.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 8 36 14 41 / 40 0 0 0
TULIA 12 38 22 43 / 40 0 0 0
PLAINVIEW 15 37 23 46 / 50 0 0 0
LEVELLAND 14 38 22 47 / 70 0 0 0
LUBBOCK 16 39 23 48 / 70 0 0 0
DENVER CITY 19 38 25 49 / 70 10 0 0
BROWNFIELD 18 40 23 49 / 70 10 0 0
CHILDRESS 23 45 29 55 / 40 0 0 0
SPUR 22 43 27 53 / 70 10 0 0
ASPERMONT 27 47 28 55 / 70 10 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR TXZ021-
022-027>030-033>036-039>042.
&&
$$
05/99
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
557 PM CST THU JAN 22 2015
.AVIATION...
WE HAVE LIKELY SEEN THE LAST OF THE LIFR FOR THIS EVENT.
CEILINGS AT KPLV ARE CURRENTLY IN THE IFR RANGE AND ARE FORECASTED
TO IMPROVE AFTER 03Z. OTHERWISE EXPECT CURRENT MVFR CIGS TO GIVE
WAY TO VFR AFTER MIDNIGHT AS THE SYSTEM AND THE LIGHT SNOW
ASSOCIATED WITH THE UPPER LEVEL LOW EXITS SOUTH AND EAST. WINDS
WILL BE LIGHT OVERNIGHT AND MAINTAIN THEIR NORTHERLY COMPONENT
BEFORE BACKING TOWARD THE WEST LATE FRIDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 306 PM CST THU JAN 22 2015/
SHORT TERM...
WATER VAPOR IMAGERY SHOWING A VIGOROUS STORM SYSTEM CONTINUING TO
MOVE SEWD THROUGH SRN NEW MEXICO. THE POSITIVELY TILTED TROUGH THAT
EXTENDS NEWD FROM THE BASE OF THE TROUGH /FROM SRN NEW MEXICO
THROUGH THE TEXAS PANHANDLE/ PRODUCING THE LAST BIT OF LIFT
ACROSS THE WRN AND CNTL PARTS OF THE FCST AREA. 18Z WRF-NAM AND
MORNING RUNS OF THE HRRR IN PRETTY GOOD AGREEMENT IN SHIFTING
LIGHT TO OCCASIONALLY MODERATE SNOWFALL SEWD IN TIME. SOME MODEST
ACCUMULATIONS GENERALLY LESS THAN 1/2 INCH REMAIN POSSIBLE WITH
THE HEAVIEST SNOW...BUT IT WILL BE MOVING INTO AN AREA THAT HAS
BEEN AT OR ABOVE FREEZING THIS AFTN. DO NOT ANTICIPATE ANY
PROBLEMS ASSOCIATED WITH THE SNOWFALL FROM LUBBOCK TO THE EAST AND
SOUTHEAST...SO CURRENT CONFIGURATION OF THE WINTER WEATHER
ADVISORY SHOULD SUFFICE.
PRECIP LIKELY TO COME TO AN END BY MIDNIGHT WITH POSSIBLE EXCEPTION
OF THE FAR SRN PART OF THE FCST AREA WHERE WILL KEEP SLIGHT CHC TO
LOW END CHANCE MENTION ATTM.
SOME CLEARING EXPECTED FROM NW TO SE BY SUNRISE. THAT CLEARING
ACROSS THE NWRN ZONES COMBINED WITH SNOW COVER SHOULD ALLOW TEMPS
THERE TO DROP TO OR BELOW COLD END OF MOS GUIDANCE WHILE FARTHER
EAST LOW TEMPS NEAR A MOS BLEND MORE LIKELY. HIGH TEMPS FRIDAY
WILL BE TRICKY. INSOLATION AND MODEST WEST WIND TO BE COUNTERACTED
ACROSS THE NWRN THIRD OF THE FCST AREA BY THE SNOW FIELD. WILL
CONTINUE TO UNDERCUT GUIDANCE THERE AND LEAN CLOSER TO MOS FURTHER
TO THE EAST AND SOUTHEAST.
LONG TERM...
NORTHWEST FLOW WILL MOVE OVERHEAD FOR THE WEEKEND INTO NEXT WEEK
LEADING TO DRY CONDITIONS AND A STEADY WARMUP UNDERNEATH INCREASING
HEIGHTS/THICKNESSES ALOFT WITH RIDGING DOMINATING THE WESTERN CONUS
AND TROUGHING ENCOMPASSING POINTS EAST. ASIDE FROM SOME SCATTERED
CIRRUS SATURDAY...OWING TO ENERGY ALOFT BEING SHUNTED SOUTHWEST
TOWARD THE GULF OF CALIFORNIA WITH DEVELOPMENT OF A CUTOFF
LOW...MOSTLY SUNNY SKIES WILL BE IN THE OFFING. TEMPERATURES SHOULD
GRADUALLY WARM INTO THE 40S/50S SATURDAY AND NEAR 50 IN VICINITY OF
LINGERING SNOWPACK IN THE FAR SOUTHWEST PANHANDLE TO MID 60S IN THE
ROLLING PLAINS SUNDAY. A BACKDOOR FRONT MAY BRING A NORTHERLY WIND
SHIFT BY MONDAY AS A DISTURBANCE DIVES ACROSS THE UPPER
MIDWEST/GREAT LAKES INTO THE OHIO VALLEY...BUT NO CHANGE IN AIRMASS
LOOKS TO BE IN STORE LOCALLY. FURTHER WARMING WELL INTO THE 60S
SHOULD OCCUR THROUGH THE WEEK AS UPPER RIDGING APPROACHES FROM THE
WEST. MAY SEE A COOLDOWN BACK TO NEAR AVERAGE BY MID-LATE WEEK IF
PACIFIC MOISTURE CAN ADVECT NORTHEAST AHEAD OF A SERIES OF PROGGED
DISTURBANCES.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 8 36 14 41 / 20 0 0 0
TULIA 12 38 22 43 / 30 0 0 0
PLAINVIEW 15 37 23 46 / 30 0 0 0
LEVELLAND 14 38 22 47 / 50 0 0 0
LUBBOCK 16 39 23 48 / 50 0 0 0
DENVER CITY 19 38 25 49 / 60 10 0 0
BROWNFIELD 18 40 23 49 / 60 10 0 0
CHILDRESS 23 45 29 55 / 30 0 0 0
SPUR 22 43 27 53 / 70 10 0 0
ASPERMONT 27 47 28 55 / 70 10 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR TXZ021-
022-027-028-033-034-039>042.
&&
$$
07/31/55
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
254 PM CST WED JAN 21 2015
.DISCUSSION...
THIS PACKAGE LOOKS VERY SIMILAR TO THE LAST ONE. RAIN HAS ALREADY
STARTED NEAR COLEMAN AND THE PRECIP SHIELD CONTINUES TO MOVE
NORTHEAST TOWARDS NORTH/CENTRAL TX. WE EXPECT THE RAIN TO START
ALONG THE I-35 CORRIDOR BEFORE MIDNIGHT AND IN EASTERN ZONES BY
EARLY MORNING. CURRENT STORM TOTAL QPF RUNS FROM ABOUT AN INCH IN
NORTHWESTERN COUNTIES TO OVER TWO INCHES IN SOUTHEASTERN
COUNTIES.
WE CONTINUE TO FORECAST RAIN TO MIX WITH SNOW BY THURSDAY MORNING
IN NORTHWESTERN COUNTIES...BUT TEMPERATURES WILL REMAIN ABOVE
FREEZING AND ONLY GRASSY SURFACES ARE EXPECTED TO ACCUMULATE UP
TO A FEW TENTHS OF AN INCH. TEMPERATURES WILL CLIMB DURING THE
DAY TO AROUND 40 IN THOSE AREAS...AND A CHANGE BACK TO RAIN BY
AFTERNOON SHOULD MELT/WASH AWAY ANY SNOW THAT REMAINS FROM THE
MORNING.
ONE FACTOR THAT MAY IMPACT SNOW ACCUMULATIONS IS IF BANDING
PRECIPITATION SETS UP. THESE BANDS OF HEAVIER PRECIP TEND TO COOL
THE ATMOSPHERE AND THE RAIN/SNOW MIX MAY CHANGE TO ALL SNOW.
GUIDANCE IS NOT GOOD AT PREDICTING EXACTLY WHERE/WHEN THESE
MESOSCALE FEATURES WILL EXIST UNTIL THE EVENT GETS CLOSER...AND
THE HIGHER RESOLUTION SHORT TERM MODELS ARE A BIG HELP. CURRENTLY
THE HRRR RUNS THROUGH 09Z THURSDAY...AND IT IS NOT SHOWING ANY
STRONG BANDS YET.
THE HEAVIER PRECIPITATION SHOULD CONTINUE THROUGH THURSDAY
AFTERNOON...AND THEN BECOME GENERALLY LIGHTER WITH LESS AREAL
COVERAGE BY THURSDAY EVENING. AS THE ATMOSPHERE DRIES OUT
THURSDAY NIGHT INTO FRIDAY MORNING...PRECIPITATION WILL BECOME
MORE SCATTERED. ONCE AGAIN...FRIDAY MORNING WILL BRING COOLER
TEMPERATURES AND EXCEPT IN THE SOUTH AND SOUTHEAST...PRECIP THAT
DOES OCCUR WILL LIKELY BE A RAIN/SNOW MIX ONCE AGAIN. WE DO NOT
EXPECT ANY SNOW ACCUMULATIONS OTHER THAN A POSSIBLE TENTH OF AN
INCH OR SO ON GRASSY SURFACES IN WESTERN THROUGH NORTHERN
COUNTIES.
THE METROPLEX MAY SEE SNOW FLAKES MIXED WITH RAIN...BUT
TEMPERATURES SHOULD REMAIN IN THE MID 30S OR ABOVE AND THERE
SHOULD BE NO ACCUMULATIONS. AREAS SOUTHEAST OF A LINE FROM
LAMPASAS TO ATHENS WILL LIKELY SEE NO SNOW AT ALL. RAIN WILL
LIKELY END EARLY FRIDAY AFTERNOON IN EASTERN COUNTIES AS THE
SYSTEM CONTINUES TO MOVE OUT.
THE REST OF THE FORECAST IS DRY...AND AS SKIES CLEAR OUT FRIDAY
NIGHT...SATURDAY MORNING LOWS WILL HOVER AROUND FREEZING ACROSS
MUCH OF THE AREA. A WARM UP BEGINS ON SATURDAY WITH HIGHS IN THE
60S EXPECTED BY SUNDAY AND CONTINUING INTO WEDNESDAY. 84
&&
.AVIATION...
/ISSUED 1146 AM CST WED JAN 21 2015/
/18Z TAFS/
CONCERNS...LOWERING INTO IFR CIGS AND MVFR VISY OVERNIGHT AS RAIN
INCREASES ACROSS THE REGION.
A LOW CLOUD DECK IN THE CENTRAL TEXAS AREA IS RESULTING IN MVFR
CONDITIONS AT KACT WHERE CIGS ARE BETWEEN 015-017 KFT. WHILE THERE
MAY BE INTERMITTENT BREAKS...EXPECT MVFR CIGS TO PREVAIL AT KACT
FOR THE REMAINDER OF THE DAY. IN THE METROPLEX...VFR CONDITIONS
WILL PREVAIL THIS AFTERNOON WITH A GRADUAL LOWERING OF CIGS INTO
MVFR BY LATE THIS EVENING.
WIDESPREAD RAIN IS EXPECTED TO DEVELOP TONIGHT IN ADVANCE OF AN
UPPER LEVEL DISTURBANCE CURRENTLY NEAR THE FOUR CORNERS AREA. SOME
RAIN MAY OCCUR LATE THIS AFTERNOON BUT THE RAIN IS MORE LIKELY TO
BEGIN THIS EVENING...INCREASING IN INTENSITY OVERNIGHT. CIGS WILL
CONTINUE TO LOWER INTO IFR CATEGORY OVERNIGHT WITH VISBYS LOWER
INTO MVFR. THE RAIN WILL PERSIST INTO THURSDAY WITH LIFR CIGS
POSSIBLE AS WELL. THE CURRENT TAF KEEPS CIGS IN IFR CATEGORY BUT
FUTURE ISSUANCES MAY NEED TO LOWER INTO LIFR CATEGORY AS EARLY AS
EARLY THURSDAY MORNING.
EAST-NORTHEAST WINDS TODAY AT SPEEDS LESS THAN 12 KTS WILL
INCREASE OVERNIGHT AND SHIFT TO THE NORTHEAST AND NORTH-NORTHEAST.
WIND SPEEDS EARLY THURSDAY MORNING AND THURSDAY WILL PREVAIL 20-25
KTS WITH GUSTS APPROACHING 30-35 KTS AT TIMES. THESE SPEEDS ARE
NOT EXPECTED TO RESULT IN ANY SIGNIFICANT CROSSWIND ISSUES ON N-S
RUNWAYS BUT MAY CAUSE SOME CONCERNS ON MORE NW-SE RUNWAYS. THE WET
RUNWAYS WILL LIKELY ALSO CAUSE SOME ADDITIONAL CONCERNS IN
ADDITION TO THE STRONGER WINDS.
THE PRECIPITATION AT THE TAF SITES IS EXPECTED TO REMAIN AS ALL
LIQUID RAIN THROUGH THIS PERIOD. IT IS POSSIBLE THAT SOME SNOW
FLAKES COULD MIX WITH THE RAIN IN THE METROPLEX ON THURSDAY.
BETTER CHANCES FOR A RAIN/SNOW MIX AT THE METROPLEX AIRPORTS ARE
LATE THURSDAY NIGHT/FRIDAY MORNING...BUT WITH SURFACE TEMPERATURES
REMAINING ABOVE FREEZING...NO ACCUMULATIONS OR IMPACTS ARE
EXPECTED.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 42 42 35 48 33 / 100 100 40 30 5
WACO, TX 44 44 37 49 31 / 100 100 50 30 10
PARIS, TX 41 43 36 48 31 / 100 100 50 30 5
DENTON, TX 40 42 35 48 30 / 100 100 40 20 5
MCKINNEY, TX 41 42 35 48 31 / 100 100 40 30 5
DALLAS, TX 42 43 35 49 34 / 100 100 40 30 5
TERRELL, TX 43 43 37 48 32 / 100 100 50 30 5
CORSICANA, TX 43 44 37 48 32 / 100 100 50 30 10
TEMPLE, TX 45 45 38 50 32 / 100 100 50 30 10
MINERAL WELLS, TX 40 42 34 49 30 / 100 100 40 20 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1102 PM CST TUE JAN 20 2015
.DISCUSSION...
FOG THICKENING UP QUICKLY ACROSS THE COASTAL COUNTIES WITH MANY
SITES REPORTING 1/4-1/2 MILE. FRONTAL BOUNDARY LOOKS TO HAVE
SLOWED DRAMATICALLY NEAR CLL WHERE T/TD SPREAD IS STILL 8 DEGREES
AND UTS IS 4 DEGREES WITH LIGHT NE-ENE WINDS. HAVE EXPANDED THE
DENSE FOG ADVISORY ANOTHER TIER OF COUNTIES NORTHWARD. FOR THE
PREVIOUS ADVISORY HAVE EXTENDED IT ANOTHER HOUR TO 8 AM. MODELS
CONTINUE TO SHOW BOUNDARY WITH ONLY A SLOW SOUTHWARD DRIFT
OVERNIGHT.
45
&&
.PREV DISCUSSION... /ISSUED 917 PM CST TUE JAN 20 2015/
DISCUSSION...
FOG SHOULD BE THE ISSUE TONIGHT. SPLIT CHANNEL SATELLITE IMAGERY
SHOWS LOW CLOUDS AND FOG FORMING NEAR THE COAST AND SPREADING
INLAND TO THE COASTAL COUNTIES. BPT AT 1/4 MILE AND PSX/GLS/ARM
ARE DOWN TO 1 TO 3 MILES. VERY FAVORABLE CONDITIONS EXIST FOR
RADIATIONAL FOG DEVELOPMENT AND SEAS FOG ALREADY DEVELOPING.
FRONTAL BOUNDARY NEARING CLL/DKR. NOT CERTAIN THAT THE FRONTAL
BOUNDARY WILL END THE THREAT FOR FOG BUT MAY FAVOR A LOW STRATUS
DECK. ATTM HAVE A DENSE FOG ADVISORY UP FOR AREAS ALONG AND SOUTH
OF AN EDNA-SUGARLAND-HOUSTON-LIBERTY LINE TIL 7 AM...BUT MAY NEED
TO EXPAND THE ADVISORY AREA A LITTLE FURTHER NORTH SO WILL BE
KEEPING A CLOSE EYE TO THE OBSERVATIONS TONIGHT. RAIN SHOULD HOLD
OFF UNTIL MID TO LATE MORNING IN THE WEST. 45
PREV DISCUSSION... /ISSUED 630 PM CST TUE JAN 20 2015/
AVIATION...
MAIN AVIATION CONCERNS CENTER AROUND REDUCED VISIBILITIES FROM
FOG AS WELL AS THE DEVELOPMENT OF IFR /POTENTIALLY LIFR/ STRATUS
OVERNIGHT.
VFR CONDITIONS WILL CONTINUE THROUGH THE EVENING HOURS BEFORE
DETERIORATING LATE TONIGHT AS FOG DEVELOPS AHEAD OF A FRONTAL
BOUNDARY /PRESENTLY LOCATED IN CENTRAL TEXAS/. BOTH THE RAP AND
HRRR CONTINUE TO SHOW CEILINGS AND VISIBILITIES DROPPING TO IFR AT
THE TERMINALS BETWEEN 06-09Z AS LOW LEVEL MOISTURE INCREASES.
CONFIDENCE REMAINS LOW ON HOW MUCH VISIBILITIES WILL DROP OVER THE
NORTHERN TERMINALS /MAINLY COLLEGE STATION AND HUNTSVILLE/ AS THE
FRONT WILL CLEAR THESE SITES AROUND 09Z. THE FRONT WILL CONTINUE
TO MAKE ITS WAY ACROSS THE TERMINALS...REACHING THE COASTAL SITES
AROUND SUNRISE. EXPECT VISIBILITIES TO IMPROVE BEHIND THE
FRONT...WITH CEILINGS GENERALLY BECOMING MVFR TOWARDS MIDDAY. RAIN
CHANCES BEGIN TO INCREASE TOWARDS THE END OF THE TAF PERIOD AS AN
UPPER LEVEL DISTURBANCE APPROACHES...BUT PROBABILITY WAS TOO LOW
TO INCLUDE IN TAF AT THIS TIME.
OTHERWISE...EXPECT GENERALLY SOUTHERLY WINDS THIS EVENING AROUND
5 TO 8 KNOTS TO BECOME LIGHT AND VARIABLE OVERNIGHT. WINDS BECOME
MORE NORTHEASTERLY 5 TO 8 KNOTS BEHIND THE COLD FRONT WEDNESDAY
MORNING AND THEN EASTERLY AROUND 10 KNOTS WEDNESDAY AFTERNOON.
HUFFMAN
PREV DISCUSSION... /ISSUED 248 PM CST TUE JAN 20 2015/
DISCUSSION...
AT 2 PM...SURFACE HIGH PRESSURE WAS LOCATED OVER THE NORTHERN GULF
COAST AND A WEAK COLD FRONT EXTENDED FROM PINE BLUFF TO JUST
SOUTH OF DFW TO MAF. MAIN ISSUE IN THE SHORT TERM IS SEA FOG
POTENTIAL...HOW FAR THE FOG WILL MOVE INLAND...TIMING THE ONSET
AND VISIBILITY RESTRICTIONS. WATER TEMPS ARE 50-51 AND SFC DEW PTS
ARE NEAR 60 SO CONDITIONS SEEM RIPE FOR DENSE SEA FOG TO DEVELOP.
THE HRRR DID A GREAT JOB TIMING THE ONSET AND AREA OF FOG
DEVELOPMENT LAST NIGHT SO WILL LEAN TOWARD THE HRRR SOLUTION
TONIGHT. ATTM...DENSE FOG SHOULD DEVELOP NEAR THE COAST BETWEEN
00-01Z AND GRADUALLY EXPAND INLAND. THE WEAK FRONT TO THE NORTH
WILL BE MOVING SOUTH AND WILL CROSS THE CWA BY 09Z. AM NOT SURE
HOW THIS FEATURE WILL AFFECT FOG POTENTIAL LATE TONIGHT. STRONGER
WINDS BEHIND THE BOUNDARY COULD PROVIDE ENOUGH MIXING TO LIFT THE
FOG INTO A LOW STRATUS. A DENSE FOG ADVISORY WILL LIKELY BE
REQUIRED LATER TONIGHT FOR COASTAL COUNTIES AND PROBABLY THE NEXT
TIER OF COUNTIES INLAND.
FCST SOUNDINGS SHOW SATURATION INCREASING ON WEDNESDAY AS
ISENTROPIC UPGLIDE BEGINS. PROBABLY GET SOME VERY LIGHT RAIN
DURING THE DAY...ESPECIALLY IN THE AFTERNOON AS SATURATION
DEEPENS. AN UPPER LEVEL TROUGH OVER CA WILL MOVE EAST ON WEDNESDAY
AND APPROACH THE 4 CORNERS REGION WED NIGHT. WINDS ALOFT WILL
BECOME SOUTHWEST AND A SERIES OF WEAK UPPER LEVEL DISTURBANCES
WILL BEGIN TO TRAVERSE SE TX. IN ADDITION...AN AREA OF LOW
PRESSURE WILL DEVELOP OVER DEEP SOUTH TEXAS AND THIS FEATURE WILL
HELP FOCUS LOW LEVEL CONVERGENCE ACROSS THE COASTAL PLAINS INTO SE
TX BY EARLY THURSDAY. SE TX WILL ALSO LIE IN A STRENGTHENING
120-140 KT RRQ WHICH WILL ALSO ASSIST LIFT. PW VALUES WILL
INCREASE WED NIGHT INTO THURSDAY REACHING 1.50 INCHES AROUND 18Z
THURSDAY. THIS IS 2 STD DEV ABOVE NORMAL FOR THIS TIME OF YEAR.
FCST SOUNDINGS SHOW A SKINNY SATURATED PROFILE FROM THE SFC TO 300
MB SO RAINFALL COULD GET BRIEFLY HEAVY THURSDAY MORNING INTO THE
EARLY AFTN. RAIN SHOULD DIMINISH QUICKLY THURSDAY NIGHT AS THE
COASTAL LOW EXITS THE REGION. THAT SAID...STRONG JET DYNAMICS AND
LIFT ON THE EAST SIDE OF THE TROUGH AXIS SHOULD KEEP PERIODS OF
VERY LIGHT RAIN OR DRIZZLE GOING THROUGH MUCH OF FRIDAY.
UPPER FLOW BECOMES CONFLUENT FRIDAY NIGHT AND MSTR LEVELS BEGIN TO
DROP SO ANY REMAINING LT RAIN WILL COME TO AN END. CLEARING SKIES
ARE EXPECTED FRIDAY NIGHT WITH ONLY PERIODS OF CIRRUS CLOUDS
EXPECTED THROUGH THE WEEKEND. AN EXPANDING UPPER LEVEL RIDGE OVER
CA WILL CREATE A NW FLOW OVER TEXAS KEEPING THINGS DRY AND
SEASONAL FOR MUCH OF NEXT WEEK. THE UPPER FLOW WILL BEGIN TO
FLATTEN TOWARD THE END OF NEXT WEEK AS ANOTHER STORM SYSTEM
APPROACHES THE DESERT SOUTHWEST. 43
MARINE...
MOIST AND WARM AIR OVER COOLER SHALLOW SHELF WATERS INCREASING THE
PROBABILITY OF RETURN SEA FOG THIS EVENING...QUICKLY BECOMING DENSE
THROUGH MIDNIGHT AND PERSISTING THROUGH A GOOD MAJORITY OF WEDNESDAY
MORNING. IF FOG DOES FORM...VISIBILITIES WILL FALL TO A MILE OR
UNDER THUS PROMPTING AN OVERNIGHT MARINE DENSE FOG ADVISORY. AN
EMERGING WESTERN STORM SYSTEM WILL ORIENT THE LATE WEEK PRESSURE
GRADIENT FROM NORTHEAST TO SOUTHWEST...ULTIMATELY GENERATING A
MODERATE TO STRONG NORTHEASTERLY FETCH THURSDAY...BACKING MORE
NORTHERLY WITH A COLD FRONTAL PASSAGE FRIDAY. THIS FETCH WILL
PRODUCE HIGHER COASTAL WATER LEVELS/TIDES AND CHURN THE OPEN SEAS TO
GREATER THAN 6 FEET NEARSHORE...10 FEET OFFSHORE THURSDAY
NIGHT/EARLY FRIDAY MORNING. OFFSHORE WIND GUSTS TO GALE ARE ALSO
LIKELY DURING THIS THURSDAY-FRIDAY PERIOD OF HIGH WIND...SEAS AND
RAIN. MUCH IMPROVED WEEKEND WEATHER WITH A WEAKENING NORTHWEST TO
WEST WIND UNDER SLIGHTLY WARMER CONDITIONS. 31
CLIMATE...
HOUSTON REACHED 70 DEGREES AGAIN TODAY. THIS IS THE THIRD
CONSECUTIVE DAY WITH TEMPS AT OR ABOVE 70 DEGREES. THE LAST TIME
HOUSTON RECORDED 3 CONSECUTIVE DAYS WITH TEMPS AT OR ABOVE 70
DEGREES WAS BACK ON DEC 11...DEC 12 AND DEC 13. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 51 64 50 51 40 / 0 20 80 100 40
HOUSTON (IAH) 53 66 54 55 42 / 10 20 60 100 60
GALVESTON (GLS) 58 63 57 58 45 / 10 20 50 100 60
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...DENSE FOG ADVISORY UNTIL 8 AM CST WEDNESDAY FOR THE FOLLOWING
ZONES: BRAZORIA...CHAMBERS...FORT BEND...GALVESTON...
HARRIS...JACKSON...LIBERTY...MATAGORDA...WHARTON.
DENSE FOG ADVISORY UNTIL 6 AM CST WEDNESDAY FOR THE FOLLOWING
ZONES: AUSTIN...COLORADO...MONTGOMERY...POLK...SAN
JACINTO...WALLER.
GM...DENSE FOG ADVISORY UNTIL 8 AM CST WEDNESDAY FOR THE FOLLOWING
ZONES: GALVESTON BAY...MATAGORDA BAY...WATERS FROM FREEPORT
TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM HIGH
ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...45
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1156 AM CST WED JAN 21 2015
.UPDATE...THIS AFTERNOON
ISSUED AT 1155 AM CST WED JAN 21 2015
A 925 TO 850 MB TROUGH WILL LINGER ACROSS THE AREA THIS AFTERNOON.
SOUNDINGS CONTINUE TO SHOW THAT LIFT UP TO 800 MB WILL CONTINUE
THROUGH MUCH OF THE AFTERNOON AND THEN SLOWLY WEAKEN AND BECOME
LESS DEEP THIS AFTERNOON. THIS LIFT WILL KEEP THE LIGHT SNOW GOING
ACROSS THE AREA SOUTH OF INTERSTATE 95. ADDITIONAL SNOW AMOUNTS
WILL BE UP TO A HALF INCH. WHILE THERE WILL BE LITTLE SNOW...MOST
WILL CONTINUE TO SEE IT...SO WENT WITH A HIGH PRECIPITATION
CHANCE.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 215 AM CST WED JAN 21 2015
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED UPPER RIDGING OVER THE EAST PACIFIC INTO SOUTHWEST CANADA...
AN UPPER LOW TRAVERSING THE SOUTHERN FORECAST AREA...AND TROUGHING
OVER EASTERN CANADA. WEAK MID LEVEL FRONTOGENESIS COMBINED WITH
ABOUT 0.4 OF AN INCH OF PRECIPITABLE WATER PER 00Z RAOB DATA HAS
ALLOWED LIGHT SNOW TO PERSIST ACROSS LOCATIONS MAINLY
ALONG/SOUTHWEST OF I-94. THE AIRMASS ACROSS THE FORECAST AREA WAS
ALSO RELATIVELY WARM...NOTED BY AIR TEMPERATURES FROM THE LOW 20S TO
LOW 30S AND 850MB TEMPS OF -6 TO -8C. THESE READINGS HAVE KEPT SNOW
TO WATER RATIOS DOWN IN THAT 10-15 TO 1 RANGE...LIMITING
ACCUMULATIONS TO MOSTLY AT 1.5 INCHES OR LESS.
EXPECT THE SNOW TO BE ON A WANING TREND TODAY. THIS IS IN RESPONSE
TO THE UPPER LOW SHIFTING OFF TO THE EAST INTO LOWER MICHIGAN...
PRODUCING MID LEVEL SUBSIDENCE IN ITS WAKE...AS WELL AS THE MID-
LEVEL FRONTOGENESIS FALLING APART. IN FACT...MUCH OF THE SNOW COULD
BE DONE BY 18Z...BUT KEPT SOME 20 PERCENT CHANCES GOING THROUGH THE
AFTERNOON PER SOME HIGH RESOLUTION MODEL GUIDANCE KEEPING SOME VERY
LIGHT SNOW OR FLURRIES GOING. WITH THE WEAKENING FORCING THROUGHOUT
THE DAY...ANY ADDITIONAL ACCUMULATION SHOULD BE LESS THAN 1 INCH.
NEVERTHELESS...A SLIPPERY MORNING COMMUTE IS POSSIBLE FOR THOSE
ROADS THAT ARE NOT PLOWED OR TREATED.
ALTHOUGH THE SNOW IS TAPERING OFF...CLOUD COVER IS LIKELY TO HANG
AROUND THROUGH TONIGHT...DUE TO THE MID-LEVEL SUBSIDENCE TRAPPING
MOISTURE AND CYCLONIC LOW LEVEL FLOW. THESE CLOUDS WILL HAMPER
TEMPERATURES FROM CLIMBING MUCH...LIKELY AT MOST TO THOSE OF
YESTERDAY. A LITTLE BIT OF COLD ADVECTION IS PROGGED TONIGHT AS
925MB TEMPS FALL FROM -4 TO -6C AT 00Z TO -6 TO -8C AT 12Z. THIS
COOLING SHOULD ALLOW TEMPERATURES TO DIP INTO THE MID TEENS TO MID
20S DESPITE THE CLOUD COVER.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 215 AM CST WED JAN 21 2015
A PIECE OF THE UPPER RIDGING OVER SOUTHWEST CANADA IS PROGGED TO
MOVE INTO THE REGION FOR THURSDAY INTO THURSDAY NIGHT. THIS RIDGING
ALOFT COMBINED WITH A SURFACE RIDGE DROPPING SOUTH THROUGH THE
REGION SHOULD HELP IN CLEARING THE SKIES OUT ON THURSDAY. THE
CLEARING LOOKS TEMPORARY AS WARM ADVECTION MID CLOUDS RETURN LATE
THURSDAY NIGHT. ALTHOUGH 925MB TEMPS ARE A BIT COLDER ON THURSDAY
COMPARED TO TODAY...MORE SUNSHINE SHOULD HELP PRODUCE SIMILAR
READINGS AGAIN. TEMPERATURES COULD TANK A BIT EARLY IN THE EVENING
BEFORE INCREASING WINDS CAUSE READINGS TO RISE...PARTICULARLY
ALONG AND WEST OF THE MISSISSIPPI RIVER. GUIDANCE LOWS IN THE MID
TEENS TO MID 20S SEEM REASONABLE.
FRIDAY LOOKS TO BE THE WARMEST...AND BREEZIEST...DAY OF THE WORK
WEEK. A SHORTWAVE IS PROGGED TO DROP THROUGH SOUTHEAST THROUGH
NORTHERN MN INTO NORTHERN WI...INCREASING THE PRESSURE GRADIENT
ACROSS THE AREA. 925MB SOUTHWEST WINDS IN THE 25-40 KT RANGE ARE
SUGGESTED BY THE 21.00Z GFS/ECMWF...BRINGING THE RESPECTIVE TEMPS UP
TO 0 TO -3C. MIXING MIGHT BE SOMEWHAT REDUCED BY MID CLOUD
COVER...BUT HIGHS SHOULD BE ABLE TO TOP OUT IN THE 30S TO POSSIBLY
LOW 40S. THESE READINGS SHOULD ALLOW FOR GUSTS IN THE 20-25 MPH
RANGE OVER HIGHER TERRAIN/EXPOSED LOCATIONS. ADDITIONALLY...
ISENTROPIC LIFT AHEAD OF THE SHORTWAVE COULD PRODUCE A LITTLE LIGHT
RAIN/SNOW/SLEET MIX...DUE TO THE PRESENCE OF A WARM LAYER AND
SURFACE TEMPERATURES ABOVE FREEZING. PRECIPITATION SHOULD MOSTLY BE
CONFINED TO NORTH OF I-90 AND LIGHT AT BEST DUE TO DRY LOW TO MID
LEVEL AIR. THE FAST MOVING NATURE OF THE SHORTWAVE WILL ALLOW ANY
PRECIPITATION TO END BY FRIDAY EVENING.
NEXT ITEM OF INTEREST IS A MORE POTENT SHORTWAVE TROUGH TAKING AIM
AT THE REGION FOR LATE SATURDAY NIGHT THROUGH SUNDAY. EXACT TRACK IS
A BIT UNCERTAIN...WITH THE 21.00Z GFS HEADING THROUGH WESTERN IA...
COMPARED TO RIGHT THROUGH LA CROSSE FROM THE 21.00Z ECMWF...AND
EASTERN WI IN THE 21.00Z CANADIAN. THE TRACK WILL BE IMPORTANT AS A
FRONTOGENETIC BAND OF SNOW IS LIKELY ALONG/EAST OF ITS TRACK...WHICH
COULD BE ADVISORY WORTHY. RIGHT NOW JUST HAVE TO BROAD BRUSH WITH 30-
50 PERCENT CHANCES AND WAIT UNTIL MODELS COME TOGETHER. WOULD NOT BE
SURPRISED THE FARTHER WEST TRACK OF THE 21.00Z GFS COMES TRUE...OR
EVEN A SOLUTION FARTHER WEST. IN GENERAL...THE SNOW LOOKS TO DEPART
THE AREA BY SUNDAY EVENING...BUT CHANCES CONTINUE INTO MONDAY AS YET
ANOTHER WEAK SHORTWAVE IS PROGGED TO DROP INTO THE REGION ON
NORTHERLY FLOW. FINALLY BY TUESDAY WE COULD BREAK OUT OF THE
PRECIPITATION.
IN GENERAL...MOST OF THE TEMPERATURES THROUGHOUT THE LONG TERM
PERIOD EXPECTED TO STAY ABOVE NORMAL...DUE TO THE ARCTIC AIR ONLY
DROPPING THROUGH SOUTHEAST CANADA AND A FLOW OF MOSTLY PACIFIC AIR
INTO THE REGION. THERE SHOULD BE SOME COOL DOWN...THOUGH...FOR
SUNDAY INTO EARLY NEXT WEEK AS THE UPPER FLOW BECOMES A BIT MORE
NORTHERLY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1155 AM CST WED JAN 21 2015
A TROUGH WILL CONTINUE TO PROVIDE LIFT UP TO 800 MB THROUGH
21.21Z AND THEN IT BEGINS TO WEAKEN AND BECOME LESS DEEP. AS A
RESULT...EXTENDED THE REDUCTIONS TO VISIBILITIES /1 TO 3 MILES/
DUE TO SNOW AND BR THROUGH THIS TIME. THE LIGHT SNOW WILL THEN
CONTINUE THROUGH 22.03Z...BUT WILL NOT REDUCE VISIBILITIES ANY
FURTHER. CEILINGS THROUGHOUT THE TIME PERIOD WILL REAMIN IN THE
500 TO 1000 FOOT RANGE AT KRST AND BETWEEN 1000 AND 1500 FEET AT
KLSE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...BOYNE
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
516 AM CST WED JAN 21 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 215 AM CST WED JAN 21 2015
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED UPPER RIDGING OVER THE EAST PACIFIC INTO SOUTHWEST CANADA...
AN UPPER LOW TRAVERSING THE SOUTHERN FORECAST AREA...AND TROUGHING
OVER EASTERN CANADA. WEAK MID LEVEL FRONTOGENESIS COMBINED WITH
ABOUT 0.4 OF AN INCH OF PRECIPITABLE WATER PER 00Z RAOB DATA HAS
ALLOWED LIGHT SNOW TO PERSIST ACROSS LOCATIONS MAINLY
ALONG/SOUTHWEST OF I-94. THE AIRMASS ACROSS THE FORECAST AREA WAS
ALSO RELATIVELY WARM...NOTED BY AIR TEMPERATURES FROM THE LOW 20S TO
LOW 30S AND 850MB TEMPS OF -6 TO -8C. THESE READINGS HAVE KEPT SNOW
TO WATER RATIOS DOWN IN THAT 10-15 TO 1 RANGE...LIMITING
ACCUMULATIONS TO MOSTLY AT 1.5 INCHES OR LESS.
EXPECT THE SNOW TO BE ON A WANING TREND TODAY. THIS IS IN RESPONSE
TO THE UPPER LOW SHIFTING OFF TO THE EAST INTO LOWER MICHIGAN...
PRODUCING MID LEVEL SUBSIDENCE IN ITS WAKE...AS WELL AS THE MID-
LEVEL FRONTOGENESIS FALLING APART. IN FACT...MUCH OF THE SNOW COULD
BE DONE BY 18Z...BUT KEPT SOME 20 PERCENT CHANCES GOING THROUGH THE
AFTERNOON PER SOME HIGH RESOLUTION MODEL GUIDANCE KEEPING SOME VERY
LIGHT SNOW OR FLURRIES GOING. WITH THE WEAKENING FORCING THROUGHOUT
THE DAY...ANY ADDITIONAL ACCUMULATION SHOULD BE LESS THAN 1 INCH.
NEVERTHELESS...A SLIPPERY MORNING COMMUTE IS POSSIBLE FOR THOSE
ROADS THAT ARE NOT PLOWED OR TREATED.
ALTHOUGH THE SNOW IS TAPERING OFF...CLOUD COVER IS LIKELY TO HANG
AROUND THROUGH TONIGHT...DUE TO THE MID-LEVEL SUBSIDENCE TRAPPING
MOISTURE AND CYCLONIC LOW LEVEL FLOW. THESE CLOUDS WILL HAMPER
TEMPERATURES FROM CLIMBING MUCH...LIKELY AT MOST TO THOSE OF
YESTERDAY. A LITTLE BIT OF COLD ADVECTION IS PROGGED TONIGHT AS
925MB TEMPS FALL FROM -4 TO -6C AT 00Z TO -6 TO -8C AT 12Z. THIS
COOLING SHOULD ALLOW TEMPERATURES TO DIP INTO THE MID TEENS TO MID
20S DESPITE THE CLOUD COVER.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 215 AM CST WED JAN 21 2015
A PIECE OF THE UPPER RIDGING OVER SOUTHWEST CANADA IS PROGGED TO
MOVE INTO THE REGION FOR THURSDAY INTO THURSDAY NIGHT. THIS RIDGING
ALOFT COMBINED WITH A SURFACE RIDGE DROPPING SOUTH THROUGH THE
REGION SHOULD HELP IN CLEARING THE SKIES OUT ON THURSDAY. THE
CLEARING LOOKS TEMPORARY AS WARM ADVECTION MID CLOUDS RETURN LATE
THURSDAY NIGHT. ALTHOUGH 925MB TEMPS ARE A BIT COLDER ON THURSDAY
COMPARED TO TODAY...MORE SUNSHINE SHOULD HELP PRODUCE SIMILAR
READINGS AGAIN. TEMPERATURES COULD TANK A BIT EARLY IN THE EVENING
BEFORE INCREASING WINDS CAUSE READINGS TO RISE...PARTICULARLY
ALONG AND WEST OF THE MISSISSIPPI RIVER. GUIDANCE LOWS IN THE MID
TEENS TO MID 20S SEEM REASONABLE.
FRIDAY LOOKS TO BE THE WARMEST...AND BREEZIEST...DAY OF THE WORK
WEEK. A SHORTWAVE IS PROGGED TO DROP THROUGH SOUTHEAST THROUGH
NORTHERN MN INTO NORTHERN WI...INCREASING THE PRESSURE GRADIENT
ACROSS THE AREA. 925MB SOUTHWEST WINDS IN THE 25-40 KT RANGE ARE
SUGGESTED BY THE 21.00Z GFS/ECMWF...BRINGING THE RESPECTIVE TEMPS UP
TO 0 TO -3C. MIXING MIGHT BE SOMEWHAT REDUCED BY MID CLOUD
COVER...BUT HIGHS SHOULD BE ABLE TO TOP OUT IN THE 30S TO POSSIBLY
LOW 40S. THESE READINGS SHOULD ALLOW FOR GUSTS IN THE 20-25 MPH
RANGE OVER HIGHER TERRAIN/EXPOSED LOCATIONS. ADDITIONALLY...
ISENTROPIC LIFT AHEAD OF THE SHORTWAVE COULD PRODUCE A LITTLE LIGHT
RAIN/SNOW/SLEET MIX...DUE TO THE PRESENCE OF A WARM LAYER AND
SURFACE TEMPERATURES ABOVE FREEZING. PRECIPITATION SHOULD MOSTLY BE
CONFINED TO NORTH OF I-90 AND LIGHT AT BEST DUE TO DRY LOW TO MID
LEVEL AIR. THE FAST MOVING NATURE OF THE SHORTWAVE WILL ALLOW ANY
PRECIPITATION TO END BY FRIDAY EVENING.
NEXT ITEM OF INTEREST IS A MORE POTENT SHORTWAVE TROUGH TAKING AIM
AT THE REGION FOR LATE SATURDAY NIGHT THROUGH SUNDAY. EXACT TRACK IS
A BIT UNCERTAIN...WITH THE 21.00Z GFS HEADING THROUGH WESTERN IA...
COMPARED TO RIGHT THROUGH LA CROSSE FROM THE 21.00Z ECMWF...AND
EASTERN WI IN THE 21.00Z CANADIAN. THE TRACK WILL BE IMPORTANT AS A
FRONTOGENETIC BAND OF SNOW IS LIKELY ALONG/EAST OF ITS TRACK...WHICH
COULD BE ADVISORY WORTHY. RIGHT NOW JUST HAVE TO BROAD BRUSH WITH 30-
50 PERCENT CHANCES AND WAIT UNTIL MODELS COME TOGETHER. WOULD NOT BE
SURPRISED THE FARTHER WEST TRACK OF THE 21.00Z GFS COMES TRUE...OR
EVEN A SOLUTION FARTHER WEST. IN GENERAL...THE SNOW LOOKS TO DEPART
THE AREA BY SUNDAY EVENING...BUT CHANCES CONTINUE INTO MONDAY AS YET
ANOTHER WEAK SHORTWAVE IS PROGGED TO DROP INTO THE REGION ON
NORTHERLY FLOW. FINALLY BY TUESDAY WE COULD BREAK OUT OF THE
PRECIPITATION.
IN GENERAL...MOST OF THE TEMPERATURES THROUGHOUT THE LONG TERM
PERIOD EXPECTED TO STAY ABOVE NORMAL...DUE TO THE ARCTIC AIR ONLY
DROPPING THROUGH SOUTHEAST CANADA AND A FLOW OF MOSTLY PACIFIC AIR
INTO THE REGION. THERE SHOULD BE SOME COOL DOWN...THOUGH...FOR
SUNDAY INTO EARLY NEXT WEEK AS THE UPPER FLOW BECOMES A BIT MORE
NORTHERLY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 515 AM CST WED JAN 21 2015
LOCAL AND REGIONAL RADARS INDICATING THE BACK EDGE OF THE SNOW WAS
STARTING TO WORK SLOWLY SOUTH ACROSS THE AREA. EXPECTING TO SEE
THE LAST OF THE HEAVIER SNOW MOVE PAST BOTH TAF SITES BEFORE 15Z
WITH SOME LINGERING LIGHT SNOW HANGING ON UNTIL LATE MORNING. WILL
START BOTH TAF SITES WITH IFR CONDITIONS AND THEN TAKE THE
VISIBILITY UP TO MVFR AS THE SNOW DIMINISHES AND EVENTUALLY TO VFR
BY THE MIDDLE OF THE AFTERNOON. DESPITE THE SNOW ENDING AND THE
WEAK SURFACE BOUNDARY MOVING SOUTH OF THE AREA...THE FLOW STILL
REMAINS VERY WEAK WHICH DOES NOT BODE WELL FOR GETTING RID OF THE
CLOUDS ANYTIME SOON. WILL KEEP THE CEILINGS IFR THROUGH THE PERIOD
AT KRST WITH KLSE ON THE EDGE OF IFR TO MVFR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
215 AM CST WED JAN 21 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 215 AM CST WED JAN 21 2015
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED UPPER RIDGING OVER THE EAST PACIFIC INTO SOUTHWEST CANADA...
AN UPPER LOW TRAVERSING THE SOUTHERN FORECAST AREA...AND TROUGHING
OVER EASTERN CANADA. WEAK MID LEVEL FRONTOGENESIS COMBINED WITH
ABOUT 0.4 OF AN INCH OF PRECIPITABLE WATER PER 00Z RAOB DATA HAS
ALLOWED LIGHT SNOW TO PERSIST ACROSS LOCATIONS MAINLY
ALONG/SOUTHWEST OF I-94. THE AIRMASS ACROSS THE FORECAST AREA WAS
ALSO RELATIVELY WARM...NOTED BY AIR TEMPERATURES FROM THE LOW 20S TO
LOW 30S AND 850MB TEMPS OF -6 TO -8C. THESE READINGS HAVE KEPT SNOW
TO WATER RATIOS DOWN IN THAT 10-15 TO 1 RANGE...LIMITING
ACCUMULATIONS TO MOSTLY AT 1.5 INCHES OR LESS.
EXPECT THE SNOW TO BE ON A WANING TREND TODAY. THIS IS IN RESPONSE
TO THE UPPER LOW SHIFTING OFF TO THE EAST INTO LOWER MICHIGAN...
PRODUCING MID LEVEL SUBSIDENCE IN ITS WAKE...AS WELL AS THE MID-
LEVEL FRONTOGENESIS FALLING APART. IN FACT...MUCH OF THE SNOW COULD
BE DONE BY 18Z...BUT KEPT SOME 20 PERCENT CHANCES GOING THROUGH THE
AFTERNOON PER SOME HIGH RESOLUTION MODEL GUIDANCE KEEPING SOME VERY
LIGHT SNOW OR FLURRIES GOING. WITH THE WEAKENING FORCING THROUGHOUT
THE DAY...ANY ADDITIONAL ACCUMULATION SHOULD BE LESS THAN 1 INCH.
NEVERTHELESS...A SLIPPERY MORNING COMMUTE IS POSSIBLE FOR THOSE
ROADS THAT ARE NOT PLOWED OR TREATED.
ALTHOUGH THE SNOW IS TAPERING OFF...CLOUD COVER IS LIKELY TO HANG
AROUND THROUGH TONIGHT...DUE TO THE MID-LEVEL SUBSIDENCE TRAPPING
MOISTURE AND CYCLONIC LOW LEVEL FLOW. THESE CLOUDS WILL HAMPER
TEMPERATURES FROM CLIMBING MUCH...LIKELY AT MOST TO THOSE OF
YESTERDAY. A LITTLE BIT OF COLD ADVECTION IS PROGGED TONIGHT AS
925MB TEMPS FALL FROM -4 TO -6C AT 00Z TO -6 TO -8C AT 12Z. THIS
COOLING SHOULD ALLOW TEMPERATURES TO DIP INTO THE MID TEENS TO MID
20S DESPITE THE CLOUD COVER.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 215 AM CST WED JAN 21 2015
A PIECE OF THE UPPER RIDGING OVER SOUTHWEST CANADA IS PROGGED TO
MOVE INTO THE REGION FOR THURSDAY INTO THURSDAY NIGHT. THIS RIDGING
ALOFT COMBINED WITH A SURFACE RIDGE DROPPING SOUTH THROUGH THE
REGION SHOULD HELP IN CLEARING THE SKIES OUT ON THURSDAY. THE
CLEARING LOOKS TEMPORARY AS WARM ADVECTION MID CLOUDS RETURN LATE
THURSDAY NIGHT. ALTHOUGH 925MB TEMPS ARE A BIT COLDER ON THURSDAY
COMPARED TO TODAY...MORE SUNSHINE SHOULD HELP PRODUCE SIMILAR
READINGS AGAIN. TEMPERATURES COULD TANK A BIT EARLY IN THE EVENING
BEFORE INCREASING WINDS CAUSE READINGS TO RISE...PARTICULARLY
ALONG AND WEST OF THE MISSISSIPPI RIVER. GUIDANCE LOWS IN THE MID
TEENS TO MID 20S SEEM REASONABLE.
FRIDAY LOOKS TO BE THE WARMEST...AND BREEZIEST...DAY OF THE WORK
WEEK. A SHORTWAVE IS PROGGED TO DROP THROUGH SOUTHEAST THROUGH
NORTHERN MN INTO NORTHERN WI...INCREASING THE PRESSURE GRADIENT
ACROSS THE AREA. 925MB SOUTHWEST WINDS IN THE 25-40 KT RANGE ARE
SUGGESTED BY THE 21.00Z GFS/ECMWF...BRINGING THE RESPECTIVE TEMPS UP
TO 0 TO -3C. MIXING MIGHT BE SOMEWHAT REDUCED BY MID CLOUD
COVER...BUT HIGHS SHOULD BE ABLE TO TOP OUT IN THE 30S TO POSSIBLY
LOW 40S. THESE READINGS SHOULD ALLOW FOR GUSTS IN THE 20-25 MPH
RANGE OVER HIGHER TERRAIN/EXPOSED LOCATIONS. ADDITIONALLY...
ISENTROPIC LIFT AHEAD OF THE SHORTWAVE COULD PRODUCE A LITTLE LIGHT
RAIN/SNOW/SLEET MIX...DUE TO THE PRESENCE OF A WARM LAYER AND
SURFACE TEMPERATURES ABOVE FREEZING. PRECIPITATION SHOULD MOSTLY BE
CONFINED TO NORTH OF I-90 AND LIGHT AT BEST DUE TO DRY LOW TO MID
LEVEL AIR. THE FAST MOVING NATURE OF THE SHORTWAVE WILL ALLOW ANY
PRECIPITATION TO END BY FRIDAY EVENING.
NEXT ITEM OF INTEREST IS A MORE POTENT SHORTWAVE TROUGH TAKING AIM
AT THE REGION FOR LATE SATURDAY NIGHT THROUGH SUNDAY. EXACT TRACK IS
A BIT UNCERTAIN...WITH THE 21.00Z GFS HEADING THROUGH WESTERN IA...
COMPARED TO RIGHT THROUGH LA CROSSE FROM THE 21.00Z ECMWF...AND
EASTERN WI IN THE 21.00Z CANADIAN. THE TRACK WILL BE IMPORTANT AS A
FRONTOGENETIC BAND OF SNOW IS LIKELY ALONG/EAST OF ITS TRACK...WHICH
COULD BE ADVISORY WORTHY. RIGHT NOW JUST HAVE TO BROAD BRUSH WITH 30-
50 PERCENT CHANCES AND WAIT UNTIL MODELS COME TOGETHER. WOULD NOT BE
SURPRISED THE FARTHER WEST TRACK OF THE 21.00Z GFS COMES TRUE...OR
EVEN A SOLUTION FARTHER WEST. IN GENERAL...THE SNOW LOOKS TO DEPART
THE AREA BY SUNDAY EVENING...BUT CHANCES CONTINUE INTO MONDAY AS YET
ANOTHER WEAK SHORTWAVE IS PROGGED TO DROP INTO THE REGION ON
NORTHERLY FLOW. FINALLY BY TUESDAY WE COULD BREAK OUT OF THE
PRECIPITATION.
IN GENERAL...MOST OF THE TEMPERATURES THROUGHOUT THE LONG TERM
PERIOD EXPECTED TO STAY ABOVE NORMAL...DUE TO THE ARCTIC AIR ONLY
DROPPING THROUGH SOUTHEAST CANADA AND A FLOW OF MOSTLY PACIFIC AIR
INTO THE REGION. THERE SHOULD BE SOME COOL DOWN...THOUGH...FOR
SUNDAY INTO EARLY NEXT WEEK AS THE UPPER FLOW BECOMES A BIT MORE
NORTHERLY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1129 PM CST TUE JAN 20 2015
MAIN AVIATION CONCERNS ARE LIFR/MVFR CONDITIONS AT BOTH TAF SITES
THROUGH THE TAF PERIOD. LATEST METARS INDICATE CEILING HEIGHTS OF
AROUND 500 TO 1500 FEET ACROSS THE AREA. WEAK SURFACE LOW
OVER NORTHERN IOWA WILL CONTINUE TO WRAP LOW CLOUDS AND LIGHT
SNOW INTO THE TAF SITES OVERNIGHT AND MUCH OF THE DAY WEDNESDAY.
THE LATEST 21.00Z NAM/GFS AND 21.03Z RAP BUFKIT SOUNDINGS SHOW LOW
LEVEL MOISTURE TO PERSIST AT BOTH LSE AND RST TAF SITES THROUGH
THE TAF PERIOD. WITH THE AREA REMAINING UNDER THE INFLUENCE OF THE
SURFACE LOW...LOW LEVEL MOISTURE AND WEAK CYCLONIC FLOW
ALOFT...EXPECT THE LOW CLOUDS TO LINGER WITH LIFR...IFR AND MVFR
CEILING HEIGHT CONDITIONS TO PREVAIL AT BOTH TAF SITES THROUGH
THE TAF PERIOD. VISIBILITIES ARE EXPECTED TO IN THE VFR RANGE AT
BOTH TAF SITES...AS THE BETTER LIFT/FORCING PUSHES SOUTHEAST OF
THE AREA OVERNIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DTJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1129 PM CST TUE JAN 20 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 309 PM CST TUE JAN 20 2015
THE MAIN FOCUS INTO TOMORROW IS ON THE TRANSITION FROM DRIZZLE TO
SNOW TONIGHT ALONG WITH HOW MUCH SNOW WILL EVENTUALLY FALL.
CURRENTLY...A CLOSED MID LEVEL TROUGH IS SLOWLY PROPAGATING TO
THE SOUTHEAST ACROSS THE DAKOTAS WHILE A SURFACE LOW IN SOUTHWEST
MINNESOTA DRIFTS TO THE SOUTHEAST ALONG A STATIONARY FRONT THAT
GOES THROUGH NORTHEAST IOWA AND NORTHERN ILLINOIS. DRIZZLE AND FOG
IS TRANSITIONING TO SNOW ALONG THIS BOUNDARY...PARTICULARLY
FURTHER UPSTREAM TOWARD THE SURFACE LOW WHERE THE LIFT/MOISTURE IS
DEEPER AND GENERATING ICE. AS THIS MID LEVEL TROUGH AND SURFACE
LOW CONTINUE TO DRIFT TO THE SOUTHEAST...THIS CHANGE OVER WILL
SPREAD THROUGH THE REGION THIS EVENING. OVERALL LIFT LOOKS RATHER
WEAK THROUGH THE EVENT...SO SNOWFALL RATES TONIGHT INTO TOMORROW
LOOK LIKE THEY WILL STAY ON THE LIGHTER SIDE BUT THE BAND OF SNOW
SHOULD BE ALIGNED FROM NORTHWEST TO SOUTHEAST AND ALLOW FOR A
STRIP OF HIGHER SNOW TOTALS. NOT MUCH CHANGE IN REGARD TO
FORECAST SNOW AMOUNTS OF GENERALLY 1 TO 2 INCHES FROM SOUTHEAST
MINNESOTA INTO SOUTHWEST WISCONSIN WITH MOST OF THAT FALLING
BETWEEN MIDNIGHT AND 6AM WEDNESDAY AS THE SURFACE LOW MOVES
THROUGH.
AN INVERTED TROUGH WILL LINGER BEHIND THIS SYSTEM AND COULD BE
ENOUGH TO KEEP SOME FLURRIES OR VERY LIGHT SNOW FALLING ACROSS THE
REGION THROUGH THE REST OF WEDNESDAY WITH LITTLE TO NO ADDITIONAL
ACCUMULATIONS EXPECTED.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 309 PM CST TUE JAN 20 2015
THE MID LEVEL/SURFACE TROUGH WILL MOVE OFF TO THE SOUTH INTO
IOWA/NORTHERN ILLINOIS WEDNESDAY NIGHT AND MARK THE END OF ANY
FLURRIES ALONG WITH SOME POTENTIAL CLEARING AS DRIER AIR MOVES IN
FROM THE NORTH AND LOW LEVEL RIDGING MOVES IN. SOME WARMER LOW
LEVEL AIR WILL MOVE IN FROM THE NORTHERN PLAINS AHEAD OF A WEAK
TROUGH/FRONT WHICH WILL BRING SURFACE WINDS AROUND TO THE
SOUTHWEST. AS THE FRONT DROPS DOWN...THE ONLY LIFT SEEMS TO COME
IN THE LOW LEVELS PER 20.12Z NAM/GFS SOUNDINGS. AS THE COLD FRONT
MOVES THROUGH...THE FORCING SEEMS TO BE FAIRLY WEAK THE MOISTURE
IS LIKELY OVERDONE MAKING PRECIPITATION UNLIKELY. BASED ON THESE
SOUNDINGS...SHOULD PRECIPITATION FORM IT MAINLY WOULD BE DRIZZLE.
BEYOND THIS...THE MAIN SYSTEM OF NOTE IS WITH A SURFACE LOW THAT
IS FORECAST TO DIVE DOWN THROUGH THE DAKOTAS AND MINNESOTA
SATURDAY NIGHT INTO SUNDAY. A COUPLE INCHES OF SNOW LOOK POSSIBLE
FROM THIS SYSTEM THOUGH THE CONSISTENCY HAS NOT BEEN THERE WITH
THE TRACK WITH PREVIOUS RUNS HAVING THIS FEATURE FORMING SOUTH OF
THE REGION. THE 20.12Z GFS/ECMWF OFFER SIMILAR SCENARIOS WITH THIS
FEATURE THOUGH THE 20.12Z GEM KEEPS THE LOW TO THE NORTH IN THE
NORTHERN GREAT LAKES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1129 PM CST TUE JAN 20 2015
MAIN AVIATION CONCERNS ARE LIFR/MVFR CONDITIONS AT BOTH TAF SITES
THROUGH THE TAF PERIOD. LATEST METARS INDICATE CEILING HEIGHTS OF
AROUND 500 TO 1500 FEET ACROSS THE AREA. WEAK SURFACE LOW
OVER NORTHERN IOWA WILL CONTINUE TO WRAP LOW CLOUDS AND LIGHT
SNOW INTO THE TAF SITES OVERNIGHT AND MUCH OF THE DAY WEDNESDAY.
THE LATEST 21.00Z NAM/GFS AND 21.03Z RAP BUFKIT SOUNDINGS SHOW LOW
LEVEL MOISTURE TO PERSIST AT BOTH LSE AND RST TAF SITES THROUGH
THE TAF PERIOD. WITH THE AREA REMAINING UNDER THE INFLUENCE OF THE
SURFACE LOW...LOW LEVEL MOISTURE AND WEAK CYCLONIC FLOW
ALOFT...EXPECT THE LOW CLOUDS TO LINGER WITH LIFR...IFR AND MVFR
CEILING HEIGHT CONDITIONS TO PREVAIL AT BOTH TAF SITES THROUGH
THE TAF PERIOD. VISIBILITIES ARE EXPECTED TO IN THE VFR RANGE AT
BOTH TAF SITES...AS THE BETTER LIFT/FORCING PUSHES SOUTHEAST OF
THE AREA OVERNIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...DTJ
AREA FORECAST DISCUSSION
NWS TUCSON AZ
909 PM MST THU JAN 22 2015
.SYNOPSIS...AN UPPER LOW WILL DROP SOUTH ALONG THE NEW MEXICO
BORDER THROUGH THIS EVENING GENERATING A FEW SHOWERS ALONG THE
BORDER AND FORCING COLDER ACROSS THE STATE ON NORTHERLY BREEZES.
DRY AND MILDER WEATHER WILL RETURN THIS WEEKEND BEFORE A LOW WEST
OF BAJA DIRECTS MOISTURE NORTH AND BRINGS A THREAT OF SHOWERS TO
SOUTHERN ARIZONA SUNDAY NIGHT INTO TUESDAY.
&&
.DISCUSSION...EASTERLY SURFACE FLOW WILL CONTINUE THROUGH TOMORROW
AFTERNOON FOR MOST LOCATIONS. SURFACE GRADIENT WILL RELAX SOME
DURING THE DAY...WHICH WILL ALLOW WINDS TO DIMINISH SOME.
STILL...EXPECT ELEVATED EASTERLY WINDS TO PERSIST OVER THE NEXT
FEW DAYS. THEN FOCUS TURNS TO THE PROGGED CUTOFF LOW OFF WESTERN
BAJA COAST. THIS SYSTEM WILL ADVECT MOISTURE INTO THE AREA BRING
BACK THE POTENTIAL FOR PRECIPITATION EARLY NEXT WEEK. SEE PREV
DISCUSSION FOR FURTHER DETAILS. ALL IN ALL...CURRENT FORECAST IS
IN GOOD SHAPE SO NO UPDATES NEEDED AT THIS TIME.
&&
.AVIATION...VALID THRU 24/06Z.
VFR CONDITIONS WILL PREVAIL IN AND AROUND THE TERMINALS OVER THE
NEXT 24 HOURS. LOWER CEILINGS ARE POSSIBLE EAST OF KDUG AS AN AREA
OF LOW PRESSURE MOVES EAST OF THE AREA. LOW CLOUDS MAY OBSCURE
TERRAIN AT TIMES IN AND AROUND THE CHIRICAHUA MOUNTAINS. EAST
WINDS WILL IMPACT MOST AREAS OVERNIGHT WITH GUSTS AS HIGH AS 25
MPH. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...BRISK EAST WINDS WILL IMPACT MOST AREAS OVERNIGHT.
WIND GUSTS AS HIGH AS 25 MPH WILL BE POSSIBLE. DRY AND STABLE
WEATHER WILL BUILD BACK IN WITH WARMING TEMPERATURES THROUGH THE
WEEKEND.
MOISTURE WILL BE ON THE INCREASE EARLY NEXT WEEK AS LOW PRESSURE OFF
BAJA COAST LIFTS NORTH. SHOWER POTENTIAL WILL BE ON THE
INCREASE...WITH THE BEST CHANCE OVER WESTERN PORTIONS OF PIMA
COUNTY.
&&
.PREV DISCUSSION... /ISSUED 254 PM MST THU JAN 22 2015/
DISCUSSION...PRIMARY CONCERN FOR THE NEXT WEEK IS THE POTENTIAL FOR
SHOWERS...AND POSSIBLY A FEW THUNDERSTORMS...MONDAY AND TUESDAY.
MORE ON THAT IN A MOMENT.
CURRENTLY...VISIBLE SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOW
THE LOW CLOUDS AND LIGHT PRECIP ONGOING JUST ALONG THE AZ AND NEW
MEXICO BORDER. IN ADDITION...THE TIGHT PRESSURE GRADIENT IN PLACE
ACROSS SOUTHEAST AZ IS RESULTING IN GUSTY SURFACE WINDS. FOR
TONIGHT...WRF AND HRRR OUTPUT SUGGESTS EASTERLY LOW LEVEL FLOW WILL
CONTINUE THROUGH THE MORNING HOURS. THE RESULTING DOWNSLOPE WINDS
SHOULD KEEP LOW TEMPERATURES A FEW DEGREES HIGHER THAN MOS GUIDANCE
SUGGESTS IN VALLEY LOCATIONS TO THE WEST OF MOUNTAIN RANGES...THIS
INCLUDES LOCATIONS SUCH AS TUCSON AND SAFFORD.
THE UPPER LEVEL PATTERN MOVES INTO A TRANSITIONAL PHASE STARTING
TOMORROW AS THE UPPER LEVEL LOW PRESSURE SYSTEM IN NEW MEXICO SWEEPS
TO THE EAST...AND HIGH PRESSURE BUILDS OVER THE WESTERN U.S.. A
PRONOUNCED SHORT WAVE TROUGH EMBEDDED IN THE UPPER RIDGE DIVES SOUTH
TOWARD ARIZONA TOMORROW MORNING. THIS SHORT WAVE EVENTUALLY DIGS
SOUTHWEST...INTENSIFIES...AND BECOMES CUT OFF FROM THE MAIN PATTERN
JUST OFF THE COAST OF BAJA CALIFORNIA. THIS RESULTS IN AN UPPER
LEVEL REX BLOCK PATTERN WHERE WITH THE INTENSE HIGH PRESSURE RIDGE
EXTENDING OVER THE PACIFIC NORTHWEST AND THE CUT OFF LOW OFF THE
BAJA PENINSULA. THIS PATTERN SHOULD STICK AROUND FOR A FEW DAYS AND
WHILE THE PACIFIC NORTHWEST HEATS UP TO NEAR RECORD LEVELS...THOSE
OF US IN THE SOUTHWEST WILL SEE TEMPERATURES WARM UP A FEW DEGREES
ABOVE AVERAGE. IN ADDITION...MOIST AIR FROM THE PACIFIC WILL BE
TRANSPORTED BY THE LOW PRESSURE SYSTEM INTO SOUTHERN ARIZONA. BY
TUESDAY MORNING...PRECIPITABLE WATER VALUES WILL SKYROCKET TO AROUND
1 INCH...WHICH DOES NOT SEEM HIGH...BUT IS ACTUALLY NEAR THE 99TH
PERCENTILE FOR MID JANUARY.
ONCE THE CUT OFF LOW DISLODGES FROM THE BLOCKING PATTERN ON
MONDAY...IT WILL PUSH NORTH AND BING THE MOISTURE...ALONG WITH
PLENTY OF LIFT...TO SUPPORT PRECIPITATION ACROSS SOUTHEAST ARIZONA.
RIGHT NOW...IT APPEARS THE BEST SHOT FOR PRECIPITATION WILL TAKE
PLACE TUESDAY MORNING THROUGH THE AFTERNOON HOURS. SNOW LEVELS
SHOULD REMAIN FAIRLY HIGH AS THIS SYSTEM WILL BE RELATIVELY WARM FOR
MID JANUARY GIVEN ITS TIME SPENT OFF THE BAJA PENINSULA. RIGHT
NOW...WE ARE THINKING SNOW LEVELS MAY FALL TO AROUND 8000 FEET OR
SO. THEIR SHOULD BE SUFFICIENT COLD AIR ALOFT...AND WARM LOW LEVEL
AIR...TO SUPPORT A LIGHTNING STRIKE OR TWO. THE CURRENT FORECAST
DOES NOT MENTION THUNDERSTORMS AS I AM NOT CONFIDENT ON EXACTLY
WHERE THUNDER IS MOST LIKELY...BUT THE FAVORED AREA IS PIMA COUNTY
TO THE WEST. RAINFALL AMOUNTS ARE STILL UP IN THE AIR...BUT WE COULD
SEE A FEW TENTHS WITH A ISOLATED AMOUNTS NEAR ONE HALF INCH.
FOLLOWING THE EARLY WEEK SYSTEM...THE UPPER PATTERN BECOMES MORE
PROGRESSIVE AND GIVES WAY TO SHORT TERM RIDGING THROUGH MID
WEEK...FOLLOWED BY ANOTHER LOW PRESSURE SYSTEM BY NEXT WEEKEND. THE
ECMWF EVEN SUGGESTS ANOTHER REX BLOCK PATTERN STARTING NEXT
FRIDAY...WHILE THE GFS IS MORE PROGRESSIVE AND BRINGS A TROUGH
THROUGH BY SATURDAY. EITHER WAY...THE LONG TERM FORECAST IS FAIRLY
UNSETTLED AT THIS POINT.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
306 AM CST FRI JAN 23 2015
.SHORT TERM...
302 AM CST
THROUGH SATURDAY...
EARLY MORNING WATER VAPOR IMAGERY SHOWS A CLOSED UPPER LOW
SPINNING OVER TEXAS AS PART OF A LARGER SCALE TROUGH THAT IS CUT
OFF FROM THE MAIN STREAM OF FLOW TO THE NORTH. THIS MAIN STREAM IS
POSITIONED ACROSS SOUTHERN CANADA WITH WITH SEVERAL EMBEDDED WAVES
TRACKING ACROSS MANITOBA AND SASKATCHEWAN TOWARD THE UPPER MIDWEST
AND UPPER GREAT LAKES. FURTHER WEST...LOW AMPLITUDE RIDGING IS
POSITIONED OVER THE WEST COAST WITH A WELL- DEFINED TROUGH MOVING
EASTWARD TOWARDS BRITISH COLUMBIA. AT THE SURFACE...HIGH PRESSURE
IS STRETCHED FROM THE SOUTHERN PLAINS TO NEW ENGLAND WITH A
SURFACE LOW OFF THE LOUISIANA COAST IN CONJUNCTION WITH THE TEXAS
UPPER LOW. ANOTHER SURFACE LOW IS OVER NORTHERN ONTARIO IN
CONJUNCTION WITH ONE OF THE WAVES OVER CENTRAL CANADA WITH A
TROUGH AXIS EXTENDING SOUTHWARD ACROSS THE NORTHERN PLAINS.
ABUNDANT BUT THIN CLOUD COVER REMAINS ACROSS THE REGION WITH
SATELLITE SHOWING VERY SLOW EASTWARD MOVEMENT...WITH THE BACK EDGE
STILL ACROSS EASTERN IOWA.
THE CLOUD COVER WILL BE THE MAIN CHALLENGE TODAY. FORECAST SOUNDINGS
SHOW A MIX OF THOUGHTS ON HOW LONG CLOUD COVER WILL HANG ON AND DO
NOT SEE MUCH IMPROVEMENT THROUGH LATE MORNING...THOUGH WESTERN AREAS
HAVE THE BEST CHANCE FOR SCATTERING BY MIDDAY. THE PRESSURE GRADIENT
WILL BEGIN TO TIGHTEN UP AS THE ONTARIO SURFACE LOW MOVES EAST AND
THE ASSOCIATED TROUGH APPROACHES. THIS WILL ALLOW FOR STEADIER
SOUTHWEST WINDS TO DEVELOP. WITH THE IDEA THAT CLOUDS WILL HANG ON
THROUGH THE MORNING THEN SCATTER THIS AFTERNOON...HIGH TEMPS WILL
PROBABLY STRUGGLE DESPITE THE SOUTHWEST WINDS AND MODEST WARM
ADVECTION ALOFT. WILL CONTINUE WITH MID AND UPPER 30S FOR NOW BUT IF
SUN CAN MAKE AN APPEARANCE FOR SEVERAL HOURS THIS AFTERNOON THEN
HIGHS AROUND 40/LOW 40S WOULD BE PLAUSIBLE. A BAND OF MID CLOUDS
WILL ACCOMPANY THE TROUGH PASSAGE EARLY THIS EVENING WITH A FEW
FLURRIES NOT OUT OF THE QUESTION. WINDS TURN NORTHWEST TONIGHT AND
SATURDAY MORNING WITH COOL ADVECTION OCCURRING. CLOUD COVER LOOKS
ABUNDANT SO HIGHS WILL LIKELY BE HELD IN THE MID/UPPER 30S.
MDB
&&
.LONG TERM...
302 AM CST
SATURDAY NIGHT THROUGH MONDAY...ATTENTION TURNS TO THE UPPER TROUGH
OFF THE BRITISH COLUMBIA COAST THIS MORNING. A SHORTWAVE EJECTS FROM
THIS TROUGH AND TRACKS EAST THEN SOUTHEAST AND ACROSS THE LOCAL AREA
EARLY SUNDAY. SURFACE LOW PRESSURE DEVELOPS AND PASSES WITH THE
UPPER TROUGH DURING THE DAY SUNDAY. GUIDANCE CONTINUES TO DISAGREE
ON THE STRENGTH AND TRACK OF THE SYSTEM WITH RECENT RUNS SHOWING
QUITE A BIT OF VARIATION. THESE NORTHWEST SYSTEMS HAVE HAD A
TENDENCY TO TRACK FURTHER SOUTH OR SOUTH AND WEST THAN DEPICTED
AHEAD OF TIME SO WILL NEED TO KEEP A CLOSE EYE ON THE WAVE AS IT
MOVES ONSHORE OVER BRITISH COLUMBIA LATER TONIGHT. AT THIS POINT...A
LOW TRACK ACROSS NORTHWEST OR WEST-CENTRAL ILLINOIS...SIMILAR TO THE
00Z GFS/ECMWF...LOOKS TO BE FAVORED WHEN CONSIDERING THE CURRENT AND
EXPECTED UPPER FLOW PATTERN. WITH WESTERN RIDGING EXPECTED TO
SHARPEN AS MORE PACIFIC ENERGY PUSHES INTO IT FROM THE WEST...THE
FLOW OVER THE ROCKIES/PLAINS WILL TURN MORE NORTHWESTERLY. ONE COULD
MAKE THE CASE THAT IF THE WAVE WERE TO TRACK THROUGH THE CURRENT
UPPER FLOW PATTERN IT WOULD TAKE A TRACK ACROSS THE AREA SO A MORE
NORTHWESTERLY FLOW WOULD SUPPORT A MORE WESTERN TRACK. A TRACK
FURTHER NORTH/EAST SEEMS UNLIKELY BUT WOULD NOT BE SURPRISED TO SEE
IT TRACK WEST OF THE TRACK OF THE 00Z GFS/ECMWF BASED ON THE
ABOVE. GIVEN THE PACIFIC ORIGINS OF THE SYSTEM THERE WILL BE
MOISTURE TO WORK WITH SO PRECIPITATION IS LIKELY WITH IT AND SHOULD
AFFECT MOST OF THE AREA UNLESS A WILD SWING IN THE TRACK OCCURS.
PRECIP TYPE MAY BE MIXED FOR A TIME AT ONSET...MAINLY SOUTH AND WEST
WITH A MORE SOUTH/WEST TRACK LEADING TO MAINLY SNOW FOR MUCH OF THE
AREA. THE 00Z RUN OF THE GFS/ECMWF SUGGEST A MIX EARLY SOUTH AS A
NOSE OF WARM AIR BRIEFLY BUILDS IN BEFORE COLD AIR FILLS IN AGAIN.
BASED ON PRECIPITABLE WATER VALUES AND DURATION OF FORCING THE HEART
OF THE SYSTEM LOOKS TO BE ABLE TO PRODUCE 0.3 TO PERHAPS 0.4 INCHES
OF LIQUID EQUIVALENT PRECIP WITH IT BECOMING A MATTER OF WHERE THE
HEART OF THE SYSTEM TRACKS.
ANOTHER ISSUE WILL BE THE POTENTIAL FOR LAKE ENHANCEMENT AS THE LOW
PASSES SUNDAY AFTERNOON/EVENING. A LOW TRACK TO THE SOUTH AND WEST
OF THE AREA WOULD BE SUPPORTIVE OF LAKE ENHANCEMENT OF SYNOPTIC
PRECIP ON THE BACK SIDE WITH THE COLUMN COLD ENOUGH TO SUPPORT SNOW
IN THIS SCENARIO. HIGH PRESSURE MOVES SOUTHWARD ACROSS ONTARIO INTO
MONDAY WITH ANOTHER SURFACE LOW/ELONGATED TROUGH STRETCHING FROM
MANITOBA TO THE CENTRAL PLAINS WHICH WILL TURN WINDS MORE EASTERLY
THEN SOUTHERLY INTO MONDAY EVENING. WITH FORECAST SOUNDINGS SHOWING
MARGINAL INVERSION HEIGHTS BUT SUFFICIENT DELTA T`S...MAY SEE A
SITUATION SIMILAR TO LAST WEEK WHERE LAKE EFFECT SNOW SHOWERS
PERSISTED IN THE EASTERLY LOW LEVEL FLOW BEFORE ENDING. THIS COULD
BE THE CASE FOR MUCH OF MONDAY. AS FAR AS TEMPS...HIGHS SUNDAY WILL
BE DICTATED BY THE LOW TRACK AND MONDAY LOOKS TO ONLY SEE HIGHS IN
THE 20S THANKS TO COLD ADVECTION.
TUESDAY THROUGH THURSDAY...BROAD RIDGING WEST AND TROUGHING EAST
WILL LEAVE THE LOCAL AREA UNDER A SHARP NORTHERLY UPPER FLOW
TUESDAY WITH HIGH PRESSURE AT THE SURFACE. THE RIDGING WILL
QUICKLY SHIFT EAST AND DE-AMPLIFY WEDNESDAY ALLOWING MILDER AIR TO
RETURN. THE FLOW MAY BE SOMEWHAT ACTIVE BUT PRECIP DETAILS ARE NOT
CLEAR AT THIS RANGE...THOUGH HAVE DECENT CONFIDENCE IN FAIRLY MILD
TEMPERATURES.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* MVFR CEILINGS AROUND 1500 FT LINGERING FRIDAY MORNING...
POSSIBLY LONGER.
* SOUTHWEST WINDS 10-15 KT...WITH A FEW HIGHER GUSTS POSSIBLE
FRIDAY AFTERNOON/EARLY EVENING.
RATZER
//DISCUSSION...UPDATED 06Z...
SURFACE HIGH PRESSURE EXTENDS FROM NORTHERN MISSOURI EAST ACROSS
INDIANA AND OHIO LATE THIS EVENING. WELL TO THE NORTH...AN AREA OF
LOW PRESSURE WAS MOVING SLOWLY EAST INTO ONTARIO. IN BETWEEN...
WEST-SOUTHWESTERLY SURFACE WINDS WILL BE THE RULE ACROSS THE UPPER
MIDWEST AND THE LOCAL TERMINALS THROUGH FRIDAY NIGHT. THE GRADIENT
WILL TIGHTEN A BIT DURING THE DAY FRIDAY...PRODUCING SUSTAINED
WINDS IN THE 12-15 KT RANGE WITH A FEW GUSTS IN THE 15-20 KT RANGE
POSSIBLE ESPECIALLY DURING THE LATER AFTERNOON AND EARLY EVENING
HOURS. AN APPROACHING SURFACE TROUGH WILL SHIFT WINDS TO THE WEST-
NORTHWEST BY EARLY SATURDAY MORNING.
SURFACE OBS AND SATELLITE IMAGERY INDICATES AN EXTENSIVE AREA OF
MVFR STRATUS ACROSS THE REGION...WHICH EXTENDS TO THE WEST ACROSS
MUCH OF EASTERN IOWA AND NORTHEAST MISSOURI. CURRENT EXTRAPOLATION
OF THE SLOW EASTWARD MOVEMENT OF THE WESTERN EDGE OF THIS CLOUD
DECK SUGGESTS MVFR CIGS COULD LINGER WELL INTO THE DAY FRIDAY
BEFORE SCATTERING...THOUGH EVENING RAOBS DEPICT THIS CLOUD LAYER
AS BEING FAIRLY SHALLOW AND PERHAPS 1000-2000 FT THICK. THIS
SUGGESTS THAT A FEW HOLES COULD DEVELOP IN THE OVERCAST EARLY THIS
MORNING WITH LARGE SCALE SINKING MOTION ALOFT...AND SOME MODEL
FORECAST SOUNDINGS SUPPORT THIS THOUGH PERHAPS COOL NEAR SFC LAYER
TOO MUCH. RECENT RAP RUNS MAINTAIN WARMER TEMPS BELOW THE STRATUS
AND DO NOT ERODE MOIST LAYER FROM ABOVE. THUS THERE IS SOMEWHAT
LOW CONFIDENCE IN CIG TRENDS THROUGH THIS MORNING. UNTIL THERE ARE
SOME SOLID SATELLITE TRENDS INDICATING EROSION OF THE MVFR DECK...
THINKING IS IT WILL LINGER UNTIL AT LEAST MID-MORNING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH IN WIND TRENDS.
* MEDIUM-LOW IN TIMING EROSION/DEPARTURE OF MVFR CIGS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...VFR/WX NIL THROUGH EVENING. CHANCE SNOW LATE NIGHT.
MVFR CIGS/VIS POSSIBLE.
SUNDAY...RAIN/SNOW MIX...CHANGING TO RAIN DURG THE AFTERNOON.
LINGERING LIGHT SNOW POSSIBLE OVERNIGHT. PERIOD OF IFR CIGS/VIS
LIKELY.
MONDAY...SLIGHT CHANCE SNOW SHOWERS EARLY. MVFR CIGS/VIS POSSIBLE.
VFR/WX NIL OVERNIGHT.
TUESDAY...VFR/WX NIL.
WEDNESDAY...VFR/WX NIL.
KREIN
&&
.MARINE...
217 AM CST
MARINE WEATHER CONCERNS INCLUDE SOUTHWESTERLY GALES ACROSS NORTHERN
LAKE MICHIGAN TODAY...THEN A BRIEF PERIOD OF STRONG NORTHEAST-NORTH
WINDS 25-30 KTS OVER CENTRAL/SOUTHERN LAKE MICHIGAN SUNDAY.
A STRONG AREA OF LOW PRESSURE WAS MOVING SLOWLY EAST ACROSS FAR
NORTHERN ONTARIO EARLY THIS MORNING...WHILE A WEST-EAST ORIENTED
RIDGE OF HIGH PRESSURE WAS ACROSS THE MIDWEST REGION SOUTH OF THE
GREAT LAKES. SURFACE PRESSURE FALLS ACROSS ONTARIO AND WESTERN
QUEBEC HAVE TIGHTENED THE GRADIENT ACROSS THE NORTHERN LAKES...AND
WILL REMAIN SO INTO THIS AFTERNOON BEFORE WEAKENING AS THE LOW
REACHES JAMES BAY AND A TRAILING SURFACE TROUGH APPROACHES FROM THE
WEST. SOUTHWEST WINDS HAVE INCREASED WITH A 34 KT GUST NOTED AT PORT
INLAND MI WITHIN THE PAST HOUR...AND A GALE WARNING IS IN EFFECT FOR
THE NORTHERN HALF OR SO OF THE LAKE THROUGH MID-AFTERNOON. WINDS
WILL EASE BELOW GALE FORCE BY LATE AFTERNOON AS THE GRADIENT BEGINS
TO WEAKEN...AND WILL FURTHER DIMINISH TONIGHT.
ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP IN ASSOCIATION
WITH AN ALBERTA-CLIPPER OVER THE WEEKEND...WITH THE LOW DEEPENING
AND MOVING QUICKLY TO NORTHWEST ILLINOIS BY SUNDAY MORNING. WINDS
WILL BECOME NORTHEASTERLY SATURDAY NIGHT AS THE LOW APPROACHES...
AND ARE EXPECTED TO QUICKLY INCREASE TO NEAR 30 KT EARLY IN THE DAY
SUNDAY AS THE LOW MOVES INTO CENTRAL INDIANA. THE PERIOD OF STRONGER
WINDS APPEARS TO BE BRIEF...AS THE LOW BEGINS TO FILL AND RAPIDLY
EXITS THE REGION TO THE SOUTHEAST SUNDAY EVENING AND WEAK HIGH
PRESSURE RIDGING MOVES IN FROM THE NORTHWEST. WEAK HIGH PRESSURE
THEN LOOKS TO LINGER ACROSS THE WESTERN GREAT LAKES INTO EARLY NEXT
WEEK.
FOR THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS...BREEZY
OFFSHORE WINDS EXPECTED TODAY AND SATURDAY. SMALL CRAFT ADVISORY
CONDITIONS ARE EXPECTED TO DEVELOP QUICKLY SUNDAY MORNING DUE TO THE
STRONG WINDS FROM THE CLIPPER...WITH THE DIMINISHING NORTH FETCH
KEEPING HIGHER WAVES LINGERING INTO EARLY MONDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3
PM FRIDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
217 AM CST FRI JAN 23 2015
.SHORT TERM...
239 PM CST
TONIGHT...MAIN FOCUS FOR TONIGHT WILL BE ON CLOUD COVER. THIS WILL
ULTIMATELY DRIVE HOW COOL SFC TEMPS CAN BECOME AS WELL.
THIS AFTERNOON VISIBLE IMAGERY SHOWS SOME STEADY THINNING IN THE
CLOUD LAYER ACROSS MUCH OF CENTRAL/NORTHERN WISC...BUT THE CLOUDS
HOLDING TOUGH ACROSS NORTHERN IL/NORTHWEST IN AND POINTS SOUTH.
TEMPS HAVE REMAINED RATHER UNIFORM IN THE LOW 30S WITH A LIGHT
WEST/NORTHWEST WIND. THE SFC RIDGE REMAINS POSITIONED OVER THE
MID-MISSOURI VALLEY...BUT DRIFTING NORTHEAST. CURRENTLY EXPECT TEMPS
TO RADIATE INTO THE LOW/MID 20S BUT LIKELY WITH THE LINGERING CLOUDS
TEMPS MAY END UP REMAINING SEVERAL DEGREES WARMER.
FRIDAY THROUGH SATURDAY...
SFC RIDGE SHUD PROVIDE A P-CLOUDY START TO FRI...HOWEVER AN
APPROACHING BOUNDARY FROM THE NORTHWEST WILL QUICKLY BRING AN
INCREASING PLUME OF MOISTURE/CLOUDS. THE SFC LOW ASSOCIATED WITH THE
BOUNDARY WILL SKIRT THE NORTHERN GREAT LAKES...BUT COULD BRING SOME
FLURRIES TO FAR NORTH/NORTHEAST IL FRI AFTN. HOWEVER MOISTURE ALONG
THE SOUTHERN FLANK APPEARS TO BE MINIMAL...SO EXPECT MAINLY JUST
CLOUDS. THE DEPARTING SFC RIDGE SHUD PROVIDE ENOUGH DRY AIR THRU FRI
EVE TO KEEP PRECIP JUST NORTH OF THE FORECAST AREA.
500MB TROUGH AXIS WILL RESIDE OVER THE GREAT LAKES REGION...ALLOWING
A SERIES OF WEAK LOBES OF VORTICITY TO QUICKLY DIVE SOUTHEAST ACROSS
THE UPPER MIDWEST INTO THE GREAT LAKES REGION. FLOW SAT TURNS
NORTH/NORTHWEST...WHICH APPEARS TO SETUP SOME LAKE EFFECT FOR AREAS
DOWNSTREAM OF LAKE MICHIGAN. FOCUS SAT NGT TURNS TOWARDS A STRONGER
SHORTWAVE POISED TO DROP SOUTH FROM CENTRAL CANADA.
TEMPS FRI/SAT WILL GENERALLY BE IN THE MID 30S...BUT WITH A WEAK
NUDGE OF WARMER AIR SAT TEMPS COULD APPROACH THE UPR 30S...TO
POSSIBLY 40 ALONG THE SOUTHERN CWFA.
BEACHLER
&&
.LONG TERM...
239 PM CST
SUNDAY THROUGH MONDAY...
GUIDANCE CONTINUES TO DEMONSTRATE SPREAD ON THE TRACK OF THE SUN
SHORTWAVE ACROSS THE GREAT LAKES REGION...WITH SOLUTIONS BRINGING
THE LOW OVER EITHER LOWER MICHIGAN TO NORTHERN IL. WEAK NOSE OF
WARM AIR IS POISED TO ADVECT NORTH PRIOR TO SFC LOW
ARRIVAL...WHICH COULD BOOST SFC TEMPS TO ARND 40. THIS WILL LIKELY
MAKE P-TYPE A CHALLENGE. AT THIS TIME GIVEN THE SPREAD AMONGST
SOLUTIONS...HAVE OPTED TO ONLY MAKE MINOR ADJUSTMENTS. WILL
FEATURE RAIN/SNOW SUN...HOWEVER IF THE LOW TRACKS FURTHER SOUTH
THIS COULD SUPPRESS THE WARMER TEMPS AND KEEP PRECIP AS ALL SNOW.
AT THIS TIME THOUGH THIS SOLUTION IS A LOW CONFIDENCE.
ONCE THE LOW SLIDES SOUTH OF THE REGION SUN NGT...FLOW QUICKLY TURNS
NORTHEAST AND FETCH COULD BE LONG ENOUGH TO BRING A PERIOD OF LAKE
EFFECT SNOW TO NORTHEAST IL. DEEP MOISTURE THEN PEELS EAST WITH FLOW
SLOWLY TURNING NORTH/NORTHWESTERLY INTO MON EVE. ROBUST THERMAL
TROUGH TRAILS THE SHORTWAVE MON...WHICH WILL HELP TO KEEP TEMPS IN
THE UPR 20S FOR HIGHS MON.
TUESDAY THROUGH THURSDAY...
WITH THE 500MB FLOW REMAINING GENERALLY FROM THE NORTHWEST
TUE/WED...ANOTHER WEAK SHORTWAVE WILL TRAVERSE THE GREAT LAKES AND
POSSIBLY BRING SOME LIGHT SNOW TUE. THEN SFC RIDGING DEVELOPS
WED/THUR AND SHOULD PROVIDE A PERIOD OF DRY WEATHER FOR THE MIDDLE
OF NEXT WEEK. GUIDANCE SUGGESTS TEMPS SHUD RETURN TO SEASONAL CONDS
TOWARDS THE MIDDLE OF NEXT WEEK.
ENSEMBLES TRANSITION TOWARDS A HIGH AMPLITUDE RIDGE LIFTING INTO
WESTERN CANADA TOWARDS THE END OF NEXT WEEK...SETTING THE STAGE FOR
MUCH COLDER AIR TO SLOWLY SLIDE SOUTHEAST ACROSS THE GREAT LAKES
TOWARDS THE SECOND HALF OF NEXT WEEK.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CEILINGS AROUND 1500 FT LINGERING FRIDAY MORNING...
POSSIBLY LONGER.
* SOUTHWEST WINDS 10-15 KT...WITH A FEW HIGHER GUSTS POSSIBLE
FRIDAY AFTERNOON/EARLY EVENING.
RATZER
//DISCUSSION...UPDATED 06Z...
SURFACE HIGH PRESSURE EXTENDS FROM NORTHERN MISSOURI EAST ACROSS
INDIANA AND OHIO LATE THIS EVENING. WELL TO THE NORTH...AN AREA OF
LOW PRESSURE WAS MOVING SLOWLY EAST INTO ONTARIO. IN BETWEEN...
WEST-SOUTHWESTERLY SURFACE WINDS WILL BE THE RULE ACROSS THE UPPER
MIDWEST AND THE LOCAL TERMINALS THROUGH FRIDAY NIGHT. THE GRADIENT
WILL TIGHTEN A BIT DURING THE DAY FRIDAY...PRODUCING SUSTAINED
WINDS IN THE 12-15 KT RANGE WITH A FEW GUSTS IN THE 15-20 KT RANGE
POSSIBLE ESPECIALLY DURING THE LATER AFTERNOON AND EARLY EVENING
HOURS. AN APPROACHING SURFACE TROUGH WILL SHIFT WINDS TO THE WEST-
NORTHWEST BY EARLY SATURDAY MORNING.
SURFACE OBS AND SATELLITE IMAGERY INDICATES AN EXTENSIVE AREA OF
MVFR STRATUS ACROSS THE REGION...WHICH EXTENDS TO THE WEST ACROSS
MUCH OF EASTERN IOWA AND NORTHEAST MISSOURI. CURRENT EXTRAPOLATION
OF THE SLOW EASTWARD MOVEMENT OF THE WESTERN EDGE OF THIS CLOUD
DECK SUGGESTS MVFR CIGS COULD LINGER WELL INTO THE DAY FRIDAY
BEFORE SCATTERING...THOUGH EVENING RAOBS DEPICT THIS CLOUD LAYER
AS BEING FAIRLY SHALLOW AND PERHAPS 1000-2000 FT THICK. THIS
SUGGESTS THAT A FEW HOLES COULD DEVELOP IN THE OVERCAST EARLY THIS
MORNING WITH LARGE SCALE SINKING MOTION ALOFT...AND SOME MODEL
FORECAST SOUNDINGS SUPPORT THIS THOUGH PERHAPS COOL NEAR SFC LAYER
TOO MUCH. RECENT RAP RUNS MAINTAIN WARMER TEMPS BELOW THE STRATUS
AND DO NOT ERODE MOIST LAYER FROM ABOVE. THUS THERE IS SOMEWHAT
LOW CONFIDENCE IN CIG TRENDS THROUGH THIS MORNING. UNTIL THERE ARE
SOME SOLID SATELLITE TRENDS INDICATING EROSION OF THE MVFR DECK...
THINKING IS IT WILL LINGER UNTIL AT LEAST MID-MORNING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH IN WIND TRENDS.
* MEDIUM-LOW IN TIMING EROSION/DEPARTURE OF MVFR CIGS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...VFR/WX NIL THROUGH EVENING. CHANCE SNOW LATE NIGHT.
MVFR CIGS/VIS POSSIBLE.
SUNDAY...RAIN/SNOW MIX...CHANGING TO RAIN DURG THE AFTERNOON.
LINGERING LIGHT SNOW POSSIBLE OVERNIGHT. PERIOD OF IFR CIGS/VIS
LIKELY.
MONDAY...SLIGHT CHANCE SNOW SHOWERS EARLY. MVFR CIGS/VIS POSSIBLE.
VFR/WX NIL OVERNIGHT.
TUESDAY...VFR/WX NIL.
WEDNESDAY...VFR/WX NIL.
KREIN
&&
.MARINE...
217 AM CST
MARINE WEATHER CONCERNS INCLUDE SOUTHWESTERLY GALES ACROSS NORTHERN
LAKE MICHIGAN TODAY...THEN A BRIEF PERIOD OF STRONG NORTHEAST-NORTH
WINDS 25-30 KTS OVER CENTRAL/SOUTHERN LAKE MICHIGAN SUNDAY.
A STRONG AREA OF LOW PRESSURE WAS MOVING SLOWLY EAST ACROSS FAR
NORTHERN ONTARIO EARLY THIS MORNING...WHILE A WEST-EAST ORIENTED
RIDGE OF HIGH PRESSURE WAS ACROSS THE MIDWEST REGION SOUTH OF THE
GREAT LAKES. SURFACE PRESSURE FALLS ACROSS ONTARIO AND WESTERN
QUEBEC HAVE TIGHTENED THE GRADIENT ACROSS THE NORTHERN LAKES...AND
WILL REMAIN SO INTO THIS AFTERNOON BEFORE WEAKENING AS THE LOW
REACHES JAMES BAY AND A TRAILING SURFACE TROUGH APPROACHES FROM THE
WEST. SOUTHWEST WINDS HAVE INCREASED WITH A 34 KT GUST NOTED AT PORT
INLAND MI WITHIN THE PAST HOUR...AND A GALE WARNING IS IN EFFECT FOR
THE NORTHERN HALF OR SO OF THE LAKE THROUGH MID-AFTERNOON. WINDS
WILL EASE BELOW GALE FORCE BY LATE AFTERNOON AS THE GRADIENT BEGINS
TO WEAKEN...AND WILL FURTHER DIMINISH TONIGHT.
ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP IN ASSOCIATION
WITH AN ALBERTA-CLIPPER OVER THE WEEKEND...WITH THE LOW DEEPENING
AND MOVING QUICKLY TO NORTHWEST ILLINOIS BY SUNDAY MORNING. WINDS
WILL BECOME NORTHEASTERLY SATURDAY NIGHT AS THE LOW APPROACHES...
AND ARE EXPECTED TO QUICKLY INCREASE TO NEAR 30 KT EARLY IN THE DAY
SUNDAY AS THE LOW MOVES INTO CENTRAL INDIANA. THE PERIOD OF STRONGER
WINDS APPEARS TO BE BRIEF...AS THE LOW BEGINS TO FILL AND RAPIDLY
EXITS THE REGION TO THE SOUTHEAST SUNDAY EVENING AND WEAK HIGH
PRESSURE RIDGING MOVES IN FROM THE NORTHWEST. WEAK HIGH PRESSURE
THEN LOOKS TO LINGER ACROSS THE WESTERN GREAT LAKES INTO EARLY NEXT
WEEK.
FOR THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS...BREEZY
OFFSHORE WINDS EXPECTED TODAY AND SATURDAY. SMALL CRAFT ADVISORY
CONDITIONS ARE EXPECTED TO DEVELOP QUICKLY SUNDAY MORNING DUE TO THE
STRONG WINDS FROM THE CLIPPER...WITH THE DIMINISHING NORTH FETCH
KEEPING HIGHER WAVES LINGERING INTO EARLY MONDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3
PM FRIDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1158 PM CST THU JAN 22 2015
.SHORT TERM...
239 PM CST
TONIGHT...MAIN FOCUS FOR TONIGHT WILL BE ON CLOUD COVER. THIS WILL
ULTIMATELY DRIVE HOW COOL SFC TEMPS CAN BECOME AS WELL.
THIS AFTERNOON VISIBLE IMAGERY SHOWS SOME STEADY THINNING IN THE
CLOUD LAYER ACROSS MUCH OF CENTRAL/NORTHERN WISC...BUT THE CLOUDS
HOLDING TOUGH ACROSS NORTHERN IL/NORTHWEST IN AND POINTS SOUTH.
TEMPS HAVE REMAINED RATHER UNIFORM IN THE LOW 30S WITH A LIGHT
WEST/NORTHWEST WIND. THE SFC RIDGE REMAINS POSITIONED OVER THE
MID-MISSOURI VALLEY...BUT DRIFTING NORTHEAST. CURRENTLY EXPECT TEMPS
TO RADIATE INTO THE LOW/MID 20S BUT LIKELY WITH THE LINGERING CLOUDS
TEMPS MAY END UP REMAINING SEVERAL DEGREES WARMER.
FRIDAY THROUGH SATURDAY...
SFC RIDGE SHUD PROVIDE A P-CLOUDY START TO FRI...HOWEVER AN
APPROACHING BOUNDARY FROM THE NORTHWEST WILL QUICKLY BRING AN
INCREASING PLUME OF MOISTURE/CLOUDS. THE SFC LOW ASSOCIATED WITH THE
BOUNDARY WILL SKIRT THE NORTHERN GREAT LAKES...BUT COULD BRING SOME
FLURRIES TO FAR NORTH/NORTHEAST IL FRI AFTN. HOWEVER MOISTURE ALONG
THE SOUTHERN FLANK APPEARS TO BE MINIMAL...SO EXPECT MAINLY JUST
CLOUDS. THE DEPARTING SFC RIDGE SHUD PROVIDE ENOUGH DRY AIR THRU FRI
EVE TO KEEP PRECIP JUST NORTH OF THE FORECAST AREA.
500MB TROUGH AXIS WILL RESIDE OVER THE GREAT LAKES REGION...ALLOWING
A SERIES OF WEAK LOBES OF VORTICITY TO QUICKLY DIVE SOUTHEAST ACROSS
THE UPPER MIDWEST INTO THE GREAT LAKES REGION. FLOW SAT TURNS
NORTH/NORTHWEST...WHICH APPEARS TO SETUP SOME LAKE EFFECT FOR AREAS
DOWNSTREAM OF LAKE MICHIGAN. FOCUS SAT NGT TURNS TOWARDS A STRONGER
SHORTWAVE POISED TO DROP SOUTH FROM CENTRAL CANADA.
TEMPS FRI/SAT WILL GENERALLY BE IN THE MID 30S...BUT WITH A WEAK
NUDGE OF WARMER AIR SAT TEMPS COULD APPROACH THE UPR 30S...TO
POSSIBLY 40 ALONG THE SOUTHERN CWFA.
BEACHLER
&&
.LONG TERM...
239 PM CST
SUNDAY THROUGH MONDAY...
GUIDANCE CONTINUES TO DEMONSTRATE SPREAD ON THE TRACK OF THE SUN
SHORTWAVE ACROSS THE GREAT LAKES REGION...WITH SOLUTIONS BRINGING
THE LOW OVER EITHER LOWER MICHIGAN TO NORTHERN IL. WEAK NOSE OF
WARM AIR IS POISED TO ADVECT NORTH PRIOR TO SFC LOW
ARRIVAL...WHICH COULD BOOST SFC TEMPS TO ARND 40. THIS WILL LIKELY
MAKE P-TYPE A CHALLENGE. AT THIS TIME GIVEN THE SPREAD AMONGST
SOLUTIONS...HAVE OPTED TO ONLY MAKE MINOR ADJUSTMENTS. WILL
FEATURE RAIN/SNOW SUN...HOWEVER IF THE LOW TRACKS FURTHER SOUTH
THIS COULD SUPPRESS THE WARMER TEMPS AND KEEP PRECIP AS ALL SNOW.
AT THIS TIME THOUGH THIS SOLUTION IS A LOW CONFIDENCE.
ONCE THE LOW SLIDES SOUTH OF THE REGION SUN NGT...FLOW QUICKLY TURNS
NORTHEAST AND FETCH COULD BE LONG ENOUGH TO BRING A PERIOD OF LAKE
EFFECT SNOW TO NORTHEAST IL. DEEP MOISTURE THEN PEELS EAST WITH FLOW
SLOWLY TURNING NORTH/NORTHWESTERLY INTO MON EVE. ROBUST THERMAL
TROUGH TRAILS THE SHORTWAVE MON...WHICH WILL HELP TO KEEP TEMPS IN
THE UPR 20S FOR HIGHS MON.
TUESDAY THROUGH THURSDAY...
WITH THE 500MB FLOW REMAINING GENERALLY FROM THE NORTHWEST
TUE/WED...ANOTHER WEAK SHORTWAVE WILL TRAVERSE THE GREAT LAKES AND
POSSIBLY BRING SOME LIGHT SNOW TUE. THEN SFC RIDGING DEVELOPS
WED/THUR AND SHOULD PROVIDE A PERIOD OF DRY WEATHER FOR THE MIDDLE
OF NEXT WEEK. GUIDANCE SUGGESTS TEMPS SHUD RETURN TO SEASONAL CONDS
TOWARDS THE MIDDLE OF NEXT WEEK.
ENSEMBLES TRANSITION TOWARDS A HIGH AMPLITUDE RIDGE LIFTING INTO
WESTERN CANADA TOWARDS THE END OF NEXT WEEK...SETTING THE STAGE FOR
MUCH COLDER AIR TO SLOWLY SLIDE SOUTHEAST ACROSS THE GREAT LAKES
TOWARDS THE SECOND HALF OF NEXT WEEK.
BEACHLER
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* MVFR CEILINGS AROUND 1500 FT LINGERING FRIDAY MORNING...
POSSIBLY LONGER.
* SOUTHWEST WINDS 10-15 KT...WITH A FEW HIGHER GUSTS POSSIBLE
FRIDAY AFTERNOON/EARLY EVENING.
RATZER
//DISCUSSION...UPDATED 06Z...
SURFACE HIGH PRESSURE EXTENDS FROM NORTHERN MISSOURI EAST ACROSS
INDIANA AND OHIO LATE THIS EVENING. WELL TO THE NORTH...AN AREA OF
LOW PRESSURE WAS MOVING SLOWLY EAST INTO ONTARIO. IN BETWEEN...
WEST-SOUTHWESTERLY SURFACE WINDS WILL BE THE RULE ACROSS THE UPPER
MIDWEST AND THE LOCAL TERMINALS THROUGH FRIDAY NIGHT. THE GRADIENT
WILL TIGHTEN A BIT DURING THE DAY FRIDAY...PRODUCING SUSTAINED
WINDS IN THE 12-15 KT RANGE WITH A FEW GUSTS IN THE 15-20 KT RANGE
POSSIBLE ESPECIALLY DURING THE LATER AFTERNOON AND EARLY EVENING
HOURS. AN APPROACHING SURFACE TROUGH WILL SHIFT WINDS TO THE WEST-
NORTHWEST BY EARLY SATURDAY MORNING.
SURFACE OBS AND SATELLITE IMAGERY INDICATES AN EXTENSIVE AREA OF
MVFR STRATUS ACROSS THE REGION...WHICH EXTENDS TO THE WEST ACROSS
MUCH OF EASTERN IOWA AND NORTHEAST MISSOURI. CURRENT EXTRAPOLATION
OF THE SLOW EASTWARD MOVEMENT OF THE WESTERN EDGE OF THIS CLOUD
DECK SUGGESTS MVFR CIGS COULD LINGER WELL INTO THE DAY FRIDAY
BEFORE SCATTERING...THOUGH EVENING RAOBS DEPICT THIS CLOUD LAYER
AS BEING FAIRLY SHALLOW AND PERHAPS 1000-2000 FT THICK. THIS
SUGGESTS THAT A FEW HOLES COULD DEVELOP IN THE OVERCAST EARLY THIS
MORNING WITH LARGE SCALE SINKING MOTION ALOFT...AND SOME MODEL
FORECAST SOUNDINGS SUPPORT THIS THOUGH PERHAPS COOL NEAR SFC LAYER
TOO MUCH. RECENT RAP RUNS MAINTAIN WARMER TEMPS BELOW THE STRATUS
AND DO NOT ERODE MOIST LAYER FROM ABOVE. THUS THERE IS SOMEWHAT
LOW CONFIDENCE IN CIG TRENDS THROUGH THIS MORNING. UNTIL THERE ARE
SOME SOLID SATELLITE TRENDS INDICATING EROSION OF THE MVFR DECK...
THINKING IS IT WILL LINGER UNTIL AT LEAST MID-MORNING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH IN WIND TRENDS.
* MEDIUM-LOW IN TIMING EROSION/DEPARTURE OF MVFR CIGS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z SATURDAY-12Z THURSDAY...UPDATED 00Z...
SATURDAY...VFR/WX NIL THROUGH EVENING. CHANCE SNOW LATE NIGHT.
MVFR CIGS/VIS POSSIBLE.
SUNDAY...RAIN/SNOW MIX...CHANGING TO RAIN DURG THE AFTERNOON.
LINGERING LIGHT SNOW POSSIBLE OVERNIGHT. PERIOD OF IFR CIGS/VIS
LIKELY.
MONDAY...SLIGHT CHANCE SNOW SHOWERS EARLY. MVFR CIGS/VIS POSSIBLE.
VFR/WX NIL OVERNIGHT.
TUESDAY...VFR/WX NIL.
WEDNESDAY...VFR/WX NIL.
KREIN
&&
.MARINE...
150 PM CST
WINDS WILL BEGIN TO INCREASE OVER THE OPEN WATERS OUT OF THE
WEST-SOUTHWEST THIS EVENING AS AN AREA OF LOW PRESSURE SHIFTS
SOUTHEASTWARD FROM NORTHERN MANITOBA INTO NORTHWESTERN ONTARIO. THIS
SYSTEM WILL SET UP A STOUT PRESSURE GRADIENT OVER THE LAKE AS HIGH
PRESSURE SETS UP FROM THE PLAINS TO THE OHIO VALLEY. THIS SHOULD
SUPPORT A PERIOD OF GALE FORCE WINDS OVER THE NORTHERN 1/3RD OR SO
OF LAKE MICHIGAN INTO FRIDAY. WIND SPEEDS ACROSS FAR SOUTHERN LAKE
MICHIGAN WILL LIKELY REMAIN LIGHTER DUE TO THE CLOSER PROXIMATE TO
THE SURFACE HIGH. THEREFORE...SMALL CRAFT ADVISORY CONDITIONS ARE NOT
ANTICIPATED FOR THE ILLINOIS AND INDIANA NEAR SHORES. NO CHANGES
HAVE BEEN MADE TO THE TIMING OF THE CURRENT GALE WARNING.
A COLD FRONT...ASSOCIATED WITH THE AFOREMENTIONED SURFACE LOW...WILL
SHIFT ACROSS THE LAKE INTO SATURDAY. THIS WILL SET UP A PERIOD OF
LIGHTER NORTHWESTERLY WINDS. ANOTHER CLIPPER SYSTEM IS EXPECTED TO
APPROACH THE LAKE BY SUNDAY. HOWEVER...THERE CONTINUES TO BE
UNCERTAINTY ON WHERE THIS SYSTEM WILL TRACK. THIS WILL HAVE LARGE
CONSEQUENCES ON THE WIND FORECAST FOR SUNDAY. IF THE SYSTEM TRACKS
TO THE SOUTH OF THE LAKE...THIS COULD LEAD TO A PERIOD OF STOUT EAST
NORTHEASTERLY WINDS DOWN MUCH OF THE LAKE...WHICH COULD PRODUCE
HIGHER WAVES INTO THE ILLINOIS AND INDIANA NEAR SHORES. HOWEVER...A
FARTHER NORTH TRACK WOULD RESULT IN A SHORTER PERIOD OF NORTHERLY
WINDS ON SUNDAY...ESPECIALLY ACROSS THE SOUTHERN END OF LAKE
MICHIGAN. AT THIS TIME...GALE FORCE WINDS ARE NOT ANTICIPATED WITH
THIS SYSTEM. HOWEVER...25 TO 30 KT WINDS ARE POSSIBLE.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3
PM FRIDAY.
&&
$$
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
406 AM EST FRI JAN 23 2015
.SYNOPSIS...
ISSUED AT 400 AM EST FRI JAN 23 2015
HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY BUT SKIES WILL
REMAIN CLOUDY THIS MORNING BUT A FEW BREAKS IN THE CLOUD COVER
MAY DEVELOP THIS AFTERNOON. HIGH TEMPERATURES TODAY WILL
GENERALLY BE IN THE 30S AND LOWS TONIGHT WILL GENERALLY BE IN THE
20S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EST FRI JAN 23 2015
ANOTHER QUIET SHORT TERM PERIOD WITH CLOUDS AND TEMPS THE ONLY
CONCERN. AS WE SUSPECTED LAST NIGHT...CLOUD COVER REMAINED LOCKED
IN ACROSS THE REGION THIS MORNING UNDERNEATH STRONG INVERSION WITH
WEAK FLOW. CLOUD COVER HAS BEEN EXPANDING NORTHEAST OVERNIGHT WITH
WEAK SOUTHWEST FLOW ALOFT. BACK EDGE OF CLOUD SHIELD CURRENTLY
ACROSS IA INTO MO AND THIS HAS BEEN ADVANCING SLOWLY EAST LAST FEW
HOURS. FORECAST SOUNDINGS VARY DEPENDING ON MODEL CHOICE. WRF
MODELS ALONG WITH HRRR AND RUC GENERALLY SHOW LOW LEVEL MOISTURE
AND INVERSION HANGING TOUGH THROUGH TONIGHT BEFORE CLOUD COVER
WITH NEXT SHORT WAVE ARRIVES. OTHER MODELS SHOW MUCH LESS MOISTURE
BY AFTERNOON SUGGESTING THINNING CLOUD COVER WITH BREAKS. THIS IS
ALWAYS A DILEMMA IN MID WINTER WITH WEAK MIXING AND LOW SUN ANGLE
AND SOMETIMES WE SEE THE CLEARING AND OTHER TIMES WE DO NOT. HAVE
INCREASED CLOUD COVER TODAY OVERALL WITH CLOUDY THIS MORNING BUT
DID TRY AND DEVELOP SOME BREAKS THIS AFTERNOON GIVEN SATELLITE
TRENDS AND 00Z SOUNDINGS SHOWING RELATIVELY THIN MOISTURE DEPTH.
THIS WILL IMPACT TEMPS AS OVERCAST SKIES THROUGH THE DAY WILL ONLY
ALLOW FOR A COUPLE DEGREE RISE WHILE BREAKS WOULD LEAD TO A FEW
MORE DEGREES IN WARMING. MET MOS SEVERAL DEGREES COLDER THAT MAV
AND EC GIVEN ITS PESSIMISTIC OUTPUT. HAVE OPTED TO STAY WITH A
CONSENSUS BLEND IN MIDDLE OF GUIDANCE ENVELOPE.
NEXT SHORT WAVE AND WEAK SURFACE BOUNDARY WILL APPROACH LATE
TONIGHT. NOT EXPECTING MUCH WITH THIS SYSTEM OTHER THAN CLOUDS AND A
VERY LOW CHANCE FOR SNOW SHOWERS NEAR BOUNDARY. THIS SHOULD BE
CONFINED TO EXTREME NORTHERN COUNTIES AND BASICALLY LEFT A SLIGHT
CHANCE POP IN FOR COLLABORATION LATE TONIGHT.
&&
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 401 AM EST FRI JAN 23 2015
MUCH OF THE UPCOMING LONG TERM PERIOD WILL BE CHARACTERIZED BY
PERTURBED NORTHWEST FLOW WITH THE MAIN EVENT TO WATCH STILL ON
SUNDAY. FIRST WAVE WILL SWING THROUGH THE REGION SATURDAY MORNING
AND SEND A WEAK CONVERGENT BOUNDARY ACROSS OUR CWA. A SECONDARY
EMBEDDED VORT MAX WILL THEN PASS OVER OUR AREA DURING THE AFTERNOON
AND MAY TOUCH OFF A FEW ISOLATED RAIN/SNOW SHOWERS. SYNOPTIC FORCING
IS CERTAINLY WEAK BUT FORECAST SOUNDINGS SHOW DECENT LOW LEVEL LAPSE
RATES AND PLENTY OF MOISTURE IN THE LOWEST 5 KFT. THIS RAISES SOME
CONCERN FOR FREEZING DRIZZLE BUT FORECAST SOUNDINGS ALSO SHOW AT
LEAST SOME VARYING DEGREE OF SATURATION ABOVE THE -10C LEVEL AND
SHOULD PROVIDE ENOUGH ICE NUCLEI FOR JUST SNOW. MAY EVEN BE RAIN
DURING THE AFTERNOON GIVEN SURFACE TEMPS IN THE MID TO POSSIBLY
UPPER 30S BUT WITH SURFACE DEWPOINTS HOLDING AT OR BELOW
30...SUSPECT IT WILL MAINLY FALL AS SNOW AND THEN MELT QUICKLY ON
CONTACT WITH THE GROUND. THESE WARM GROUND/SURFACE TEMPS ARE ANOTHER
REASON THAT FREEZING DRIZZLE IS NOT MUCH OF A CONCERN. BEST CHANCES
FOR PRECIP WILL BE ACROSS OUR NORTH WHERE THETA-E FLUX FROM THE
LAKES MAY PROVIDE A MARGINAL BOOST TO HYDROMETEOR PRODUCTION.
MUCH MORE ROBUST PV ANOMALY DIVES INTO THE MIDWEST BY SUNDAY...ON
THE CYCLONICALLY SHEARED SIDE OF LARGELY MERIDIONAL 130 KT UPPER
LEVEL JET. AS HAS BEEN THE CASE FOR MUCH OF THIS WINTER...MODELS
STRUGGLE WITH EXACT TRACK OF SURFACE REFLECTION AND 850MB LOW.
FORECAST IS FURTHER COMPLICATED BY SURFACE TEMPERATURES RIGHT
AROUND THE FREEZING MARK. NOTABLE SOUTHERN ADJUSTMENT SEEN IN MOST
OF THE 00Z GUIDANCE. 00Z GFS...GEM...AND ECMWF NOW TRACK THE SURFACE
LOW SOUTH OF OUR CWA WITH THE ECMWF ACTUALLY GOING THROUGH SOUTHERN
INDIANA. 00Z NAM IS NOW THE NORTHERN OUTLIER. TOUGH TO IGNORE THIS
MORE SOUTH/WEST TREND BUT CONFIDENCE IN ANY PARTICULARS REMAINS LOW
WITH PARENT JET ENERGY STILL OVER THE NORTH PACIFIC. DID RAISE POPS
AND QPF AMOUNTS QUITE A BIT IN OUR SOUTHWEST CWA. ALSO TRENDED
COLDER THOUGH STILL THINK SOME RAIN MAY CUT INTO SNOW TOTALS ACROSS
AT LEAST OUR FAR SOUTHWEST. DYNAMICS WITH THIS SYSTEM ARE NOT OVERLY
IMPRESSIVE BUT SHOULD SEE A DECENT SLUG OF 285K ISENTROPIC ASCENT
AND LOW LEVEL DEFORMATION/FGEN JUST NORTH OF THE SURFACE LOW TRACK.
GOOD MOISTURE FEED TOO...WITH LOW LEVEL MIXING RATIOS AROUND 3 G/KG
AND PWATS UP TO A HALF INCH. COUPLE THIS WITH GOOD MIDLEVEL CVA AND
UPPER LEVEL SUPPORT AND MODEL QPF VALUES OF UP TO 0.4 INCHES MAY NOT
BE TOO FAR OFF. SNOW RATIOS WILL BE ON THE LOW SIDE GIVEN WARM
GROUND AND ELEVATED/SHALLOW DGZ BUT NEVERTHELESS...ADVISORY LEVEL
SNOW COULD EASILY BE POSSIBLE FOR MOST OF OUR CWA BASED ON THE
LATEST 00Z NWP GUIDANCE. WILL GO WITH A CONSERVATIVE 2-4 INCHES FOR
NOW AND SEE WHAT THE 12Z RUNS HAVE TO OFFER.
REST OF THE FORECAST LOOKS FAIRLY BENIGN. RETURN TO COLD TEMPS
EXPECTED FOR THE FIRST HALF OF THE WORK WEEK...ESPECIALLY IF WE GET
A FRESH SNOWPACK. SINGLE DIGIT LOWS AND HIGHS AROUND 20F EXPECTED
FOR A LARGE PART OF THE CWA. POTENTIAL FOR ANOTHER WEAK CLIPPER
SYSTEM ON TUESDAY BUT AIRMASS WILL BE VERY DRY AND FORCING WEAK.
PREFER A SILENT TEN POP FOR NOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1232 AM EST FRI JAN 23 2015
LOW CLOUDS REMAIN LOCKED UNDER STRONG INVERSION WITH SURFACE HIGH
PRESSURE OVER THE REGION. DO NOT EXPECT THIS MVFR CLOUD DECK TO
DISSIPATE OVERNIGHT AS SOUTHWEST FLOW ALOFT IS LOCKING INVERSION
IN PLACE AND SATELLITE SHOWS CLOUD DECK EXPANDING. LATEST HIRES
GUIDANCE INDICATES INVERSION TO HOLD THROUGH FRIDAY WITH MOISTURE
TRAPPED OVER OUR AREA. SUBSIDENCE COULD WORK ON THE THIN LAYER
DURING THE DAY BUT WOULD ONLY EXPECT SOME BREAKS TO DEVELOP IN
AFTERNOON VERSUS FULL CLEARING. THUS HAVE KEPT TAFS IN THE MVFR
RANGE FOR THE PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LASHLEY
SHORT TERM...LASHLEY
LONG TERM...AGD
AVIATION...LASHLEY
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
344 AM CST FRI JAN 23 2015
.SYNOPSIS...
ISSUED AT 320 AM CST FRI JAN 23 2015
A NORTHWEST FLOW WILL CONTINUE THROUGH THE NEXT ONE TO TWO WEEKS.
A SERIES WEATHER SYSTEMS WILL MOVE THROUGH THE AREAS OVER THE NXT
SEVERAL DAYS.
&&
.SHORT TERM /TODAY/...
ISSUED AT 320 AM CST FRI JAN 23 2015
A WEAK TROUGH LOOKS TO QUICKLY PUSH THROUGH THE STATE LATE
THIS MORNING AND INTO THE AFTERNOON. THERE IS SOME WEAK 700-500MB
THETA-E ADVECTION AND MID-LEVEL FORCING WITH THIS CLIPPER...BUT
TREMENDOUS AMOUNT OF DRY AIR BELOW 700MB TO THE SURFACE WILL MAKE IT
DIFFICULT FOR ANY PRECIP FALLING THROUGH THIS LAYER TO REACH THE
GROUND. LOWERED POPS AND HAVE ONLY SPRINKLES MENTIONED WITH THE
LOWER CONFIDENCE OF MEASURABLE PRECIP. THE 23.03Z HOPWRF AND LATEST
HRRR HAVE A GOOD HANDLE OF THE VERY LIGHT PRECIP/REFLECTIVITY TRENDS
LATE THIS MORNING INTO THE EARLY AFTERNOON OVER NORTHERN IOWA.
DECENT WAA AHEAD OF THE WEAK TROUGH TODAY AND WENT WELL ABOVE
GUIDANCE OVER THE CENTRAL TO SOUTH. THE RUC13 HAS A VERY GOOD HANDLE
ON THE MAX TEMPS TREND TODAY AND LEANED TOWARDS THE 23.07Z RUN. THE
CLOUD COVER MOVING IN WITH THE SHORTWAVE IS THE CAVEAT...THE
QUESTION REMAINS IF CLOUD DECK WILL MOVE IN QUICK ENOUGH TO HOLD
TEMPS DOWN. LEANED TOWARD THE WAA AND ENOUGH SUNSHINE EARLY ON IN
THE DAY TO PUT TEMPS WELL INTO THE 40S...AND THUS TWEAKED UP MAX
TEMPS OVER THE SOUTHERN HALF OF THE FORECAST.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 320 AM CST FRI JAN 23 2015
TROUGH OF LOW PRESSURE FROM NWRN MN INTO CO WILL MOVE THROUGH THE
AREAS TODAY. SWLY FLOW WILL BRING WARMER AIR TO THE STATE TODAY.
THE COOLING WILL BE SHORT LIVED AS THE NEXT WEATHER DISTURBANCE
WILL MOVE THROUGH SUNDAY INTO SUNDAY EVENING. SOME DISCREPANCY
WITH THE TRACK...HOW FAR SOUTHWEST...ON IT. THE ECMWF IS AMONG THE
FARTHEST WEST...BUT EVEN SO THE TRACK IS FAR ENOUGH TO THE
NORTHEAST THAT MUCH OF IA WILL BE IN THE RAIN AREA...OR REMAIN
DRY WITH ANY FROZEN PRECIP OVER THE FAR NORTHEAST.
A STRONGER SYSTEM WILL MOVE THROUGH MID WEEK. A STRONG PUSH OF
WARM AIR IS EXPECTED AHEAD OF THIS SYSTEM AND WENT WELL ABOVE MOS
FOR HIGHS ON WED. ONCE THE SYSTEM PASSES...A TRANSITION IN THE
PATTERN WILL BEGIN. THE STORM TRACK WILL SHIFT FARTHER TO THE WEST
AND ARCTIC AIR WILL BEGIN TO SPILL INTO THE CENTRAL U.S.
&&
.AVIATION...23/00Z
ISSUED AT 551 PM CST THU JAN 22 2015
STRATUS DECK HAS PRETTY MUCH CLEARED OUT OF THE AREA...WITH MAINLY
VFR CONDITIONS EXPECTED INTO FRIDAY. SOUTHERLY WINDS TO PICK UP
FRIDAY...AND BECOME A LITTLE GUSTY. A COLD FRONT TO MOVE THROUGH
FRIDAY EVENING...WITH WINDS SHIFTING AROUND TO THE NORTHWEST AND A
LOW STRATUS DECK TO MOVE IN WITH AT LEAST MVFR CIGS EXPECTED.
POSSIBILITY OF IFR CIGS...BUT UNCERTAINTY STILL HIGH SO HAVE GONE
WITH A MENTION OF LOW MVFR.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MS JAN 15
SHORT TERM...PODRAZIK
LONG TERM...MS JAN 15
AVIATION...BEERENDS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1134 PM CST THU JAN 22 2015
.UPDATE...
ISSUED AT 524 PM CST THU JAN 22 2015
BASED ON THE CURRENT RATE OF THE EASTWARD PROGRESSION OF THE BACK
EDGE OF THE STRATUS IN WESTERN IA...AND TRENDS OF THE HRRR AND RAP
THAT HAD A DECENT HANDLE ON THESE FEATURES...CLEARING WILL LIKELY
TAKE LONGER THAN ORIGINALLY EXPECTED. HAVE UPDATED THE FORECAST
FOR THE CLEARING TO REACH OUR WESTERN FORECAST AREA BORDER AROUND
MIDNIGHT...THEN CROSS THE MS RIVER AROUND 5 AM. THIS WOULD LEAVE
OUR ILLINOIS ZONES UNDER CLOUD COVER THROUGH THE NIGHT. FOR
NOW...HAVE MADE ONLY MINOR TWEAKS TO HOURLY TEMPERATURES...BUT
WILL NEED TO REASSESS FOR POSSIBLE WARMER LOWS WITH THE MORE
PERSISTENT CLOUD COVER.
&&
.SYNOPSIS...
ISSUED AT 346 PM CST THU JAN 22 2015
UPPER LEVEL TROUGH ALONG WITH A STRENGTHENING INVERSION AT 900 MB
TRAPPING THE LOW LEVEL MOISTURE BELOW...DESPITE SURFACE HIGH
PRESSURE OVER THE CWA. THIS HAS RESULTED IN AN EXTENSIVE AREA OF
STRATUS TODAY ACROSS THE CWA. 3 PM TEMPERATURES RANGED FROM THE
UPPER 20S TO MID 30S.
ELSEWHERE...SUBSIDENCE BEHIND THE DEPARTING TROUGH WAS CLEARING
THE SKIES IN WISCONSIN AND ALSO WESTERN IA/WESTERN MN. HOWEVER...THE
CLEARING HAS COME TO A GRINDING HALT IN SOUTHERN WI BUT CONTINUES
TO MAKE SLOW BUT STEADY PROGRESS EASTWARD IN WESTERN IA.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 346 PM CST THU JAN 22 2015
FORECAST FOCUS ON CLOUDS AND TEMPERATURES. WARMER ON FRIDAY.
TONIGHT...GRADUAL CLEARING FROM WEST TO EAST AS THE UPPER TROUGH
SHIFTS EAST AND THE FLOW BECOMES ANTI-CYCLONIC. THE SURFACE RIDGE
WILL BE SHIFTING TO OUR SOUTH ALLOWING WINDS TO BACK SOUTHWEST.
TEMPERATURES SHOULDN`T DROP TOO MUCH TONIGHT DUE TO SOUTHWEST WINDS
AND WEAK WARM AIR ADVECTION DEVELOPING. MINIMUM TEMPERATURES ARE
EXPECTED TO BE IN THE LOWER TO MID 20S...WITH THE COOLEST READINGS
IN FAR NW IL WHERE SEVERAL INCHES OF SNOW COVER EXISTS.
FRIDAY...SKIES WILL BE SUNNY IN THE MORNING THEN INCREASING CLOUDS
DURING THE AFTERNOON IN OUR NORTH...AS A WEAK SHORT WAVE DROPS
SOUTHEAST TOWARDS THE AREA IN THE NW FLOW ALOFT. WITH SOUTHWEST SURFACE
WINDS THIS SHOULD BOOST AFTERNOON TEMPERATURES INTO THE UPPER 30S
TO LOWER 40S AT MOST LOCATIONS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 335 PM CST THU JAN 22 2015
CHANCE OF RAIN/SNOW LATE SAT NGT-SUN...OTHERWISE GENERALLY DRY WITH
TEMP MOSTLY NEAR TO ABOVE NORMAL.
FRIDAY NIGHT... WEAK AND QUICK MOVING UPPER AIR DISTURBANCE TO SWEEP
THROUGH THE GREAT LAKES WITH ATTENDANT SURFACE TROUGH PASSING
ACROSS CWA. WEAK FORCING AND LIMITED MOISTURE SHOULD PRECLUDE MUCH
MORE THAN JUST INCREASING CLOUDS AND POSSIBLY FEW FLURRIES OR PATCHY
DRIZZLE NORTHEAST IA INTO NORTHWEST IL DEPENDING ON ICE INTRODUCTION
AND DEPTH OF MOISTURE. MINIMAL COOLING POST TROUGH COUPLED WITH
CLOUDINESS LENDS SUPPORT FOR STAYING NEAR WARM SIDE OF GUIDANCE ON
LOWS AND GENERALLY IN THE UPPER 20S TO AROUND 30F.
SATURDAY AND SUNDAY... MODELS STILL VARY WITH TRACK OF FAIRLY VIGOROUS
CLIPPER SYSTEM LATE SATURDAY NIGHT ALTHOUGH STARTING TO SEE SOME
TRENDS AND CLUSTERING WITH 12Z MODEL SUITE. MOST NOTABLY THE GEM HAS
TRENDED MUCH FURTHER SOUTH FROM UPPER PENINSULA OF MI TO CENTRAL WI WHICH
IS CLOSER TO TRACK OF UKMET AND OPERATIONAL GFS. THE OPERATIONAL GFS IS
ACTUALLY A LITTLE FURTHER SOUTH OF ENSEMBLE MEAN AND NEARLY ALL OF THE
MEMBERS. MEANWHILE THE ECMWF CONTINUES TO REMAIN THE FURTHEST SOUTH TAKING
THE CLIPPER SYSTEM ACROSS THE CWA. A MORE NORTHEAST TRACK WOULD RESULT
IN TAPERED PCPN CHCS FROM WEST TO EAST WITH RAIN BEING THE MORE DOMINANT
PRECIPITATION TYPE WITH SOME LIGHT SNOW OR FLURRIES POSSIBLE IN
WRAP-AROUND. MEANWHILE A TRACK FURTHER SOUTHWEST SUCH AS SHOWN BY ECMWF
COULD RESULT IN MORE SNOW WITH LIGHT ACCUMULATIONS. WITH THE MAIN SYSTEM
IN QUESTION STILL OFF THE BRITISH COLUMBIA COASTLINE AND NOT WELL SAMPLED
YET BY RAOB NETWORK IT COULD TAKE ANOTHER 12-24 HRS BEFORE THAT OCCURS AND
BEFORE WE START SEEING BETTER MODEL CONSISTENCY WITH THE TRACK. FOR NOW
THOUGH WILL CONTINUE WITH CHANCE OF PCPN OVERNIGHT SATURDAY NIGHT
THROUGH SUNDAY... WITH MAINLY RAIN WITH SOME MIX OF SNOW NORTH TRANSITIONING
TO MIX OR SNOW SUNDAY. FEELING IS A MORE SOUTHERLY TRACK PERHAPS CLOSER
TO ECMWF OR BLENDED WITH GFS REASONABLE. AS PREVIOUS SHIFTS HAVE MENTIONED
THE ORIENTATION OF THE LEFT EXIT REGION OF 150+ KT JET WITH COMPACT
SHORTWAVE TROUGH FAVORS MORE DIGGING OF SYSTEM WHICH FITS CONCEPTUALLY WITH
SYSTEM ENTERING LONGWAVE TROUGH. THIS WOULD SUPPORT MORE SOUTHERLY TRACK
WHICH IS ALSO HINTED BY GFS ENSEMBLE WITH ITS LARGEST STANDARD DEVIATION
IN 500 MB HEIGHTS OVER EASTERN IA/NORTHWEST IL SUNDAY 12Z.
TEMPS SATURDAY AND SUNDAY WILL DEPEND ON TRACK OF CLIPPER SYSTEM... BUT
IN GENERAL MUCH OF THE PERIOD SHOULD BE ABOVE FREEZING AND ABOVE NORMAL
WITH AREA RESIDING IN WARM SECTOR AHEAD OF SYSTEM. EXCEPTION BEING
SUNDAY NIGHT IN WAKE OF DEPARTING SYSTEM AS NORTHERLY WINDS WILL USHER IN
COLDER AIR AND EXPECT LOWS SUNDAY NIGHT TO DIP DOWN WELL INTO THE 20S.
MONDAY THROUGH THURSDAY... MAINLY DRY WITH SOME SUGGESTION OF ANOTHER
CLIPPER SYSTEM AROUND TUESDAY AND POSSIBLY THURSDAY BUT CONFIDENCE ON
TRACK AND IMPACT TOO LOW FOR MENTIONABLE POPS AS IT APPEARS AT THIS TIME.
TEMPS TO TAKE A BIT OF A HIT MONDAY INTO TUESDAY WITH COLDER AIR AND
MAY NEED TO BE LOWERED A BIT MORE CLOSER TO NORMAL WITH ECMWF AND GFS
SHOWING 850 TEMPS AROUND -4C TO -10C FROM WEST TO EAST SUPPORTIVE OF
GRADIENT IN TEMPS AS WELL. ANOTHER ROUND OF MP AIRMASS SHOWN BY GFS AND
ECMWF TO RETURN TO MIDWEST MID-LATE WEEK WHICH SHOULD SEND TEMPS BACK
ABOVE NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1133 PM CST THU JAN 22 2015
A PERSISTENT DECK OF LOW CLOUDS WITH BASES AROUND 1200 TO 2000 FT
AGL WAS COVERING MOST OF IL AND THE EASTERN HALF OF IA THIS
EVENING...RESULTING IN WIDESPREAD MVFR CONDITIONS. THE BACK EDGE
OF THE CLOUDS OVER CENTRAL IA CONTINUES TO SLOWLY EDGE
EASTWARD...BUT ITS PROGRESS HAS SLOWED SOME THIS EVENING. THE
LATEST FORECASTS HAVE DELAYED THE EXPECTED CLEARING TREND AND
TRANSITION TO VFR CONDITIONS BY SEVERAL HOURS...NOT REACHING CID
UNTIL WELL AFTER MIDNIGHT AND THEN THE MS RIVER SITES CLOSER TO
SUNRISE. VFR CONDITIONS AND INCREASING SOUTHWEST WINDS ARE THEN
EXPECTED FOR THE REMAINDER OF FRIDAY.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...SHEETS
SYNOPSIS...HAASE
SHORT TERM...HAASE
LONG TERM...05
AVIATION...SHEETS
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1146 PM CST THU JAN 22 2015
.AVIATION...GUMBO WEATHER CONTINUES WITH RAIN TAPERING OFF BUT IFR
CIGS ONLY GRADUALLY IMPROVING TO MVFR IN THE COLD WRAP IN THE WAKE
OF THE LOW OUT OVER THE GULF ABOUT TO HEAD EAST OF ACADIANA. COLD
ADVECTION WILL KEEP GUSTY NORTHERLY WINDS THRU FRIDAY. STILL
HOLDING OUT FOR VFR AT BPT AND LCH BY SUNDOWN FRIDAY.
SWEENEY
&&
.PREV DISCUSSION... /ISSUED 950 PM CST THU JAN 22 2015/
DISCUSSION...
REGIONAL 88DS SHOW THE BULK OF THE MODERATE/HEAVY RAINS NOW
PUSHING EAST OF THE FORECAST AREA..WITH MAYBE THE LOWER ACADIANA
ZONES STILL SEEING A LITTLE BIT OF HEAVIER PRECIP. ALL THIS WILL
CONTINUE PUSHING EWD ALONG WITH THE SFC LOW OVER THE NRN GULF...
NOW LOCATED SE OF CAMERON. BEHIND THE LARGE AREA OF RAIN REGIONAL
88DS SHOW JUST SPORADIC PATCHY LIGHT RAIN...ALTHOUGH IT CAN
CERTAINLY BE ASSUMED THAT AREAS OF DRIZZLE ARE OCCURRING WITHIN
SUCH AN EXPANSIVE STRATUS OVERCAST NOTED IN SFC OBS ACROSS THE
REGION AHEAD OF THE APPROACHING STORM SYSTEM ALOFT NOW MOVING INTO
WRN TX. BASED ON ALL THIS LOWERED POPS SOMEWHAT FOR THE REMAINDER
OF THE NIGHT...ALTHOUGH RETAINED CATEGORICAL POPS FOR THE SERN
ZONES THROUGH MIDNIGHT. ELSEWHERE JUST MINOR TWEAKS AT MOST TO THE
INHERITED GRIDS/ZONES.
UPDATE OUT SHORTLY.
25
PREV DISCUSSION... /ISSUED 547 PM CST THU JAN 22 2015/
AVIATION...RAIN WITH GUSTY WINDS AND IFR CONDITIONS CAN BE
EXPECTED TO CONTINUE FOR THE WESTERN TERMINALS BPT, LCH AND AEX.
IFR DUE TO VIS AT TIMES AT ARA AND LFT WITH PREDOMINANT MVFR.
ALL THIS DUE TO THE FRONTAL WAVE CURRENTLY APPROACHING THE UPPER
TEXAS COAST WITH A TIGHT GRADIENT PRODUCING GUSTY NORTHEAST WINDS.
RAIN SHOULD TAPER OFF TO VCSH AROUND MID MORNING FRIDAY AND END ABOUT
SUNDOWN FRIDAY WITH VFR AS THE FRONTAL WAVE PULLS UP THE EASTERN
SEABOAARD AND DRY AIR MOVES IN FROM THE NORTHWEST.
SWEENEY
PREV DISCUSSION... /ISSUED 317 PM CST THU JAN 22 2015/
DISCUSSION...
BROAD AREA OF RAIN COVERING OUR ENTIRE COUNTY WARNING AREA THIS
AFTERNOON. TEMPERATURES NOW HOVERING IN THE MID 40S TO LOWER 50S.
OUR 100 PERCENT POP FORECAST LOOKING RIGHT ON THE MONEY...SO A JOB
WELL DONE TO OUR STAFF.
ON THE LARGER CANVAS...IN THE UPPER LEVELS...A TROUGH OF LOW
PRESSURE IS CURRENTLY WORKING ACROSS WEST TEXAS WITH AN ABUNDANCE OF
ENERGY RIDING THROUGH OUR AREA AT THE MOMENT. THIS HAS SPAWNED AN
ELONGATED AREA OF SURFACE LOW PRESSURE OFF THE TEXAS OFFSHORE COASTAL
WATERS FROM BAFFIN BAY TO GALVESTON. MASSIVE AMOUNTS OF GULF
MOISTURE TRAPPED ALONG THE SOUTHEAST TEXAS & LOUISIANA COASTAL
WATERS IN A VERY RICH CONVERGENCE ZONE WHERE LARGE SWATHS OF RAIN
ARE BEING CREATED AND THEN MOVED INLAND.
OBVIOUSLY...THIS IS GOING TO CREATE A VERY GENEROUS AMOUNT OF 1 1/2
TO 2 INCH RAIN AMOUNTS WITH ISOLATED AMOUNTS UP TO THREE INCHES. THE RAIN
WILL BE HERE TO STAY THROUGH THE NIGHT AS OUR HRRR & GFS MODELS
SHOWING OUR NEWLY BORN SURFACE LOW MOVING WEST TO EAST ACROSS OUR
NORTHWEST GULF OF MEXICO THROUGH EARLY MORNING FRIDAY. I RAISED THE
WIND ADVISORY TODAY THROUGH MIDNIGHT FOR I-10 CORRIDOR SOUTH
BECAUSE THIS SURFACE LOW WILL TIGHTEN UP THE WIND FIELD ACROSS OUR
COASTAL AREAS WITH SOME GUSTS AT TIMES FURTHER NORTH AT LEAST
UNTIL MIDNIGHT.
SO...ELEVATED WINDS ARE GOING TO BE A PROBLEM UNTIL MIDNIGHT ALONG
THE COASTAL AREAS AND THE RAINS ARE GOING TO BE THE BIGGEST
PROBLEMS FOR THE ENTIRE AREA OVER THE NEXT 24 HOURS. THE SURFACE
LOW WILL MOVE EAST OF OUR AREA BY NOON FRIDAY...HOWEVER WE WILL
CONTINUE TO EXPECT LIGHT RAIN OR SHOWERS THROUGH THE AFTERNOON
FRIDAY AS THE UPPER LEVEL SYSTEM TRACKS EVEN CLOSER TO US.
RAIN SHOULD EXIT THE ENTIRE AREA BY FRIDAY NIGHT WITH HIGH
PRESSURE BUILDING BACK INTO THE AREA. THE REST OF THE FORECAST
THROUGH DAY SEVEN LOOKS DRY WITH COOL TEMPERATURES THROUGH SUNDAY
MORNING WITH A SLOW WARM-UP FOR THE REST OF NEXT WEEK.
MARINE...
SMALL CRAFT ADVISORY WILL REMAIN IN EFFECT UNTIL 6 PM FRIDAY AS SOUTHEAST
FLOW THIS AFTERNOON TRANSITIONS TO A NORTHERLY FLOW LATER TONIGHT
WITH THE PASSAGE OF A NORTHWEST GULF SURFACE LOW.
06
&&
.PRELIMINARY POINT TEMPS/POPS...
KLCH 44 48 37 57 39 / 100 30 20 10 0
KBPT 44 49 37 58 40 / 100 30 10 0 0
KAEX 41 45 34 56 36 / 100 40 20 0 0
KLFT 46 48 38 56 39 / 100 30 20 10 0
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE FOLLOWING
ZONES: ACADIA...CALCASIEU...EAST CAMERON...IBERIA...
JEFFERSON DAVIS...LAFAYETTE...LOWER ST. MARTIN...ST. MARY...
UPPER ST. MARTIN...VERMILION...WEST CAMERON.
TX...WIND ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE FOLLOWING
ZONES: JEFFERSON...ORANGE.
GM...SMALL CRAFT ADVISORY UNTIL 6 PM CST FRIDAY FOR THE FOLLOWING
ZONES: COASTAL WATERS FROM CAMERON LA TO HIGH ISLAND TX OUT
20 NM...COASTAL WATERS FROM INTRACOASTAL CITY TO CAMERON LA
OUT 20 NM...COASTAL WATERS FROM LOWER ATCHAFALAYA RIVER TO
INTRACOASTAL CITY LA OUT 20 NM...WATERS FROM INTRACOASTAL
CITY TO CAMERON LA FROM 20 TO 60 NM...WATERS FROM CAMERON
LA TO HIGH ISLAND TX FROM 20 TO 60 NM...WATERS FROM LOWER
ATCHAFALAYA RIVER TO INTRACOASTAL CITY LA FROM 20 TO 60 NM.
SMALL CRAFT EXERCISE CAUTION UNTIL MIDNIGHT CST TONIGHT FOR THE
FOLLOWING ZONES: CALCASIEU LAKE...SABINE LAKE...VERMILION
BAY.
&&
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WWW.YOUTUBE.COM/NWSLAKECHARLES
&&
$$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1155 PM EST THU JAN 22 2015
.AVIATION...
A REDUCTION IN THE COVERAGE OF STRATUS FROM THE NORTH WILL PROVIDE
POINTS FROM AT LEAST PTK NORTHWARD WITH A PERIOD OF VFR/CLEAR SKY
DURING THE EARLY MORNING PERIOD. A HIGHER DEGREE OF CLOUD COVER MAY
EXIST ACROSS THE DETROIT CORRIDOR AS SOUTHWEST FLOW PROVIDES SOME
RENEWED MOISTURE ADVECTION. THIS PROCESS WILL WORK TOWARD EXPANDING
THE STRATUS BACK NORTHWARD INTO FRIDAY. CONFIDENCE REMAINS ON THE
LOWER SIDE WITH BOTH THE OVERALL COVERAGE AND TIMING ON FRIDAY.
FOR DTW...METRO AIRSPACE CURRENTLY RESIDING ALONG THE FRINGE OF THE
EXISTING MVFR STRATUS DECK. LOWER CONFIDENCE GOING FORWARD GIVEN
RECENT VARIABILITY IN POSITIONING OF THIS CLOUD COVER AS THE FLOW
DEEPENS OUT OF THE SOUTHWEST. RECENT TRENDS WOULD SUGGEST THE
POTENTIAL IS HIGH ENOUGH TO INCLUDE A PERIOD OF VFR EARLY THIS
MORNING.
//DTW THRESHOLD PROBABILITIES...
* LOW FOR CEILING BELOW 5000 FEET TONIGHT AND FRIDAY.
&&
.PREV DISCUSSION...ISSUED 347 PM EST THU JAN 22 2015
SHORT TERM... THROUGH TONIGHT
MAIN FORECAST CHALLENGE IS WITH CLOUD COVER OVERNIGHT. SPLIT FLOW
PATTERN IN PLACE OVER NORTH AMERICA WITH SOUTHEAST MICHIGAN
POSITIONED IN THE POLEWARD ENTRANCE REGION OF A STRONG JET AXIS OVER
THE OHIO VALLEY. THIS WILL PROMOTE ACTIVE SUBSIDENCE THROUGH THE
PERIOD...AS EVIDENCED BY SPRAWLING SURFACE HIGH OVER THE WESTERN
GREAT LAKES. EXTENSIVE STRATUS DECK OVER THE UPPER MIDWEST HAS SHOWN
GOOD SIGNS OF CLEARING OVER WISCONSIN/UPPER MICHIGAN WITH BACK EDGE
OF THE STRATUS WORKING INTO NORTHERN MICHIGAN AND ACROSS LAKE
MICHIGAN. LINEAR EXTRAPOLATION OF THIS CLEARING WOULD WORK IT INTO
SOUTHEAST MICHIGAN AFTER 00Z. HOWEVER...CLIMATOLOGY IS A FACTOR
WORKING AGAINST CLEARING. NAM AND RAP RH PROGS ARE NOT MUCH HELP
HERE AS THEY DID NOT SHOW THE AREA OF CLEARING TO OUR WEST...HOWEVER
THEY DO SHOW POCKETS OF CLEARING OVER THE UPPER MIDWEST OVERNIGHT.
THE UPSHOT IS...TRENDED A BIT MORE OPTIMISTIC WITH CLOUD COVER THAN
PREVIOUS FORECAST...BUT KEPT PARTLY TO MOSTLY CLOUDY SKIES IN ORDER
THAT THE FORECAST NOT BOUNCE AROUND TOO MUCH AS CONFIDENCE IN
CLEARING SKIES IS STILL NOT HIGH.
CLOUD COVER WILL IMPACT LOW TEMPS AS WELL. SIDED WITH THE WARMER MET
MOS. SOME ROOM FOR TEMPS TO DROP BELOW FORECAST LOWS IF CLEARING IS
REALIZED...HOWEVER STILL THINK MAV MOS IS A BIT TOO LOW AS IT IS
UNDERDOING SURFACE DEWPOINTS. ALSO...INCREASING SW GRADIENT FLOW
TOWARD THE END OF THE FORECAST PERIOD SHOULD LIMIT POTENTIAL TEMP
DROP OVER NORTHERN PARTS OF THE FORECAST AREA. THE INCREASED
PRESSURE GRADIENT WILL OCCUR AS AN EXPANSIVE CYCLONE DEEPENS OVER
NORTHERN ONTARIO.
LONG TERM...FRIDAY THROUGH WEDNESDAY
UPPER LEVEL PATTERN BECOMES QUITE COMPLEX TO END THE WEEK. AMPLIFIED
RIDGING OVER THE WESTERN CONUS GET FOLDED OVER IN THE GREAT LAKES
FRIDAY WHICH TRIES TO PINCH OFF THE BASE OF THE TROUGH OVER THE FOUR
CORNERS. ENERGETIC SOUTHERN STREAM KEEPS IT FAIRLY PROGRESSIVE
PREVENTING A TRUE CUTOFF LOW FROM FORMING AS IT TRACKS ACROSS THE
SOUTHERN STATES. INCOMING NORTHERN STREAM ENERGY EVENTUALLY CARVES
OUT ANOTHER DOMINATE TROUGH BY THE END OF THE WEEKEND. AT THE
SFC...HIGH PRESSURE STRUNG OUT FROM THE CENTRAL PLAINS THROUGH THE
OHIO VALLEY AND TO THE EAST COAST ON FRIDAY WILL GET COMPRESSED
BETWEEN NORTHERN STREAM LOW TRACKING THROUGH NORTHERN ONTARIO AND
DEVELOPING SOUTHERN STREAM LOW UNDER THE AFOREMENTIONED PINCHED OFF
TROUGH. THE HIGH WILL MOVE OFF TO THE EAST BY SATURDAY AS THE
SYSTEMS DRAW NEARER EACH OTHER WITH THE ATTEMPTED PHASING OF THE
JETS. OVERALL THIS YIELDS A SOMEWHAT LOWER CONFIDENCE FORECAST AS
SLIGHT DIFFERENCES IN TIMING OF PHASING JETS OR LOCATION OF THE SFC
FEATURES USUALLY LEADS TO JUMPS IN THE FORECAST. LUCKILY IN THIS
CASE...THE PHASING IS ADVERTISED FAR ENOUGH DOWN STREAM TO NEGATE SOME
OF THE TYPICAL CONCERNS.
FOR FRIDAY...WITH HIGH PRESSURE LOCKED AT THE SFC...THE LOW PASSING
THROUGH ONTARIO WILL DROP A COLD FRONT/TROUGH THROUGH LOWER MI IN
THE AFTERNOON. WITH THE HIGH SLIDING TO OUR EAST...WINDS WILL BECOME
SOUTHWESTERLY IN THE MORNING AHEAD OF THE TROUGH AS THE RIDGE AND
TROUGH TIGHTEN THE PRESSURE GRADIENT OVER THE STATE. THESE SW WINDS
WILL BRING THE NOSE OF A THERMAL RIDGE INTO THE AREA THROUGH THE
AFTERNOON. THE WARM AIR WILL STEEPEN THE INVERSION BETWEEN 950-900MB
AS IT WARMS THE LAYER BETWEEN 700 AND 900MB. SO LOOK FOR ELEVATED
WINDS AROUND 15-20MPH WITH GUSTS TO AROUND 25MPH PEAKING IN THE
AFTERNOON. THE STOUT INVERSION WILL PREVENT BETTER MIXING FROM
BRINGING SOME OF THE HIGHER WINDS RIGHT ABOVE THE INVERSION DOWN TO
THE SFC.
THE WEAKENING COLD FRONT WILL ENTER CENTRAL MI AROUND MIDNIGHT WHICH
WILL BRING A CHANCE OF SNOW SHOWERS TO THE SAGINAW VALLEY AND
NORTHERN THUMB. MOISTURE POOLING AHEAD OF THE TROUGH IS DECENT WITH
PWATS INCREASING FROM UNDER 0.2 TO AROUND 0.5 INCHES. THE RIBBON OF
THETA E ALONG THE FRONT IS VERY NARROW WITH A GOOD GRADIENT ON THE
LEAD EDGE INITIALLY...BUT WEAKENING AS IT TRACKS THROUGH SOUTHERN
MI. SEE NO REASON TO DEVIATE FROM THE CHANCE/SLIGHT CHANCE POPS
RIGHT NOW FOR FRIDAY NIGHT. SEVERAL OTHER SMALL WAVES ARE ADVERTISED
TO SHOOT THROUGH THE DEVELOPING NW FLOW KEEPING LOW CHANCE POPS
THROUGH THE DAY SATURDAY. A SECOND...STRONGER COLD FRONT WILL DROP
INTO LOWER MI SATURDAY NIGHT STALLING ACROSS THE AREA AS THE
TRANSITION TO NW FLOW CONTINUES. WITH BL MOISTURE STILL PREVALENT
AND THE FRONT DRAPED ACROSS THE REGION WITH DECENT LAPSE RATES
THROUGH 800MB...WILL HOLD ONTO SOME LOW POP SNOW SHOWER MENTION
THROUGH SAT NIGHT.
CLIPPER DROPS OUT OF MANITOBA AND BEGINS INFLUENCING CONDITIONS
LATE SATURDAY NIGHT THROUGH SUNDAY. THIS SYSTEM COULD BRING IN
ANOTHER SHOT AT ACCUMULATING SNOW SUNDAY INTO EARLY MONDAY MORNING.
COLD AIR ADVECTION BEHIND THE FRONT ON MONDAY IS EXPECTED TO DROP
DAYTIME HIGH`S INTO THE TEENS AND LOW 20`S WITH SINGLE DIGIT
OVERNIGHT LOWS RETURNING FOR BOTH TUESDAY AND WEDNESDAY MORNING.
SCATTERED LIGHT SNOW SHOWERS WILL BE POSSIBLE ON THURSDAY AS ANOTHER
CLIPPER SWINGS THROUGH. TEMPS WARMING INTO THE LOW 30`S DURING THE
DAYLIGHT HOURS FOR THURSDAY AND FRIDAY.
MARINE...
A LOW PRESSURE SYSTEM TRACKING THROUGH CENTRAL CANADA WILL REACH
NORTHERN QUEBEC FRIDAY AFTERNOON. THIS SYSTEM WILL DROP A WEAKENING
COLD FRONT INTO THE REGION FRIDAY. THIS WILL TIGHTEN THE PRESSURE
GRADIENT BETWEEN IT AND THE EXITING SURFACE HIGH ALLOWING WINDS TO
AMPLIFY SOMEWHAT OVER CENTRAL AND NORTHERN LAKE HURON. THOUGH
SUSTAINED WINDS APPEAR TO REACH INTO THE MID 20 KNOT RANGE...WARM
AIR ALOFT AND A STEEP LOW LEVEL INVERSION APPEAR PREVENT STRONGER
GUSTS FROM REACHING THE SURFACE. FEEL FAIRLY CONFIDENT THAT WINDS
WILL GUST AT OR JUST ABOVE 30 KNOTS ACROSS NORTHERN AND CENTRAL LAKE
HURON. THOUGH GALE FORCE GUSTS CANNOT BE RULES OUT
ENTIRELY...CURRENT MODELS AND ANALYSIS SUGGEST WINDS TO THIS
STRENGTH WOULD BE QUITE SPORADIC...AND NOT WIDE SPREAD ENOUGH TO
WARRANT A GALE WARNING OR CONTINUING THE WATCH AT THIS TIME SO THE
WATCH HAS BEEN CANCELLED. EXTENSIVE ICE COVER IN THE LAKE HURON
NEARSHORE ZONES WILL PREVENT ANY WAVES DEVELOPING WITH THE OFFSHORE
FLOW TO AROUND 25 KNOTS...SO SMALL CRAFT ADVISORIES WILL NOT BE
NEEDED AT THIS TIME. COLD NORTHWEST FLOW THIS WEEKEND WILL KEEP
WINDS ELEVATED THROUGH THAT PERIOD...BUT WILL REMAIN BELOW GALE
FORCE.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MICHIGAN WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....MR
SHORT TERM...DT
LONG TERM....DRK/DE
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS JACKSON MS
328 AM CST FRI JAN 23 2015
.SHORT TERM...TODAY THROUGH SATURDAY NIGHT...STRONG DEEP LAYERED
WARM ADVECTION HAS BEEN RESPONSIBLE OVERNIGHT FOR THE WIDESPREAD
MODERATE TO AT TIMES HEAVY RAIN OVER THE CWA. CURRENT RADAR TRENDS
AND MODEL DATA IN AGREEMENT THAT THE DEEP LAYERED ASCENT WILL SHIFT
EAST TODAY LEAVING BEHIND A RAW...CLOUDY...DRIZZLY DAY FOR THE CWA.
EVEN THOUGH THE AREA IS BEING DRY SLOTTED IN ADVANCE OF THE MID/UPPER
LEVEL COLD CORE...BELIEVE BOUNDARY LAYER COOLING WILL MAINTAIN CLOUD
COVER AND PERIODS OF LIGHT RAIN/DRIZZLE. HRRR OUTPUT IS SHOWING THE
MAJORITY OF THE PRECIP CLEAR OUT OVER THE SE TWO THIRDS...BUT
MAINTAINS A NEAR STEADY BAND OF LIGHT RAIN OVER NW SECTIONS IN CLOSE
PROXIMITY TO THE DEFORMATION ZONE.
AS THE MID/UPPER LEVEL COLD CORE MOVES THROUGH TONIGHT...DEEP
LAYERED COOLING WILL ALLOW FOR RISING THETA SURFACE AND MORE LIGHT
PRECIPITATION. BUFR SOUNDINGS CONTINUE TO SHOW SOME POSSIBILITY OF
LIGHT SNOW MIXING IN WITH THE LIGHT RAIN ALONG THE HIGHWAY 82
CORRIDOR BEFORE ALL THE PRECIPITATION COMES TO AN END AFTER MIDNIGHT.
CLOUDS CLEEARING OUT DURING THE MORNING SATURDAY WILL GIVE WAY TO
SUNNY SKIES BY AFTERNOON. MAX TEMPS SHOULD BE MAKE IT INTO THE LOW TO
MID 50S./26/
.LONG TERM...SUNDAY THROUGH NEXT WORK WEEK...PRONOUNCED NORTHWEST
FLOW ALOFT WILL EXIST OVER THE REGION SUNDAY THROUGH WEDNESDAY OF
NEXT WEEK...UPSTREAM OF A LONGWAVE TROUGH CENTERED NEAR THE EAST
COAST. THIS PATTERN WILL PROMOTE A FEW CONTINENTAL COLD AIR SURGES
MAINLY EAST OF THE MS RIVER THROUGH THIS TIME...WITH ANY REAL
CHANCES OF PRECIP ASSOCIATED WITH THESE SURGES (AND MOST OF THE
CLOUDS) CONFINED WELL TO OUR NORTH AND EAST. THE GENERAL PATTERN
SUGGESTS 3 TO 4 DAYS OF EFFICIENT DAYTIME MIXING (AND THEREFORE
WARMING) WITH NIGHTS CAPABLE OF GOOD RADIATIONAL COOLING. BLENDED
GUIDANCE TEMPERATURES WERE MAINLY ON THE WARM SIDE OF AVERAGE
(ESPECIALLY ACROSS SOUTHWESTERN ZONES) AND DEVIATIONS FROM THE MAIN
BLEND WERE NOT MAJOR. HOWEVER...I DID TEND TO FOLLOW LATEST
OPERATIONAL EURO IDEA OF TIMING OF COOL AIR SURGES SUNDAY NIGHT AND
AGAIN AROUND TUESDAY NIGHT...AND SUBTLY TRENDING GUIDANCE COOLER (OR
WARMER) BASED ON THE UNDETAILED BLEND. ALL IN ALL...THIS SHOULD BE
DECENT PERIOD OF WEATHER FOR THE REGION CONSIDERING THE CALENDAR
DATE.
BY LATE IN THE WORK WEEK SOUTHERN STREAM ENERGY WILL START MAKING
INROADS TOWARD THE REGION...INCREASING CLOUDS AND GRADUALLY
INCREASING RAIN CHANCES. THE TYPICALLY-SOLID EUROPEAN OPERATIONAL
MODEL STILL IS INSISTENT ON CUTTING OFF A BIG PIECE OF THIS SOUTHERN
STREAM ENERGY NEAR BAJA CALIFORNIA...WHICH WOULD HAVE THE EFFECT OF
CONFINING INCLEMENT WEATHER MOSTLY WEST OF OUR REGION.
HOWEVER...CONSENSUS OF OTHER LONG RANGE MODELS TENDS TO PHASE THIS
ENERGY WITH THIS NORTHERN STREAM...WHICH WOULD ENSURE MUCH MORE
IMPACT IN OUR REGION. THE LATTER CONSENSUS ALSO TENDS TO SUGGESTS
ARRIVAL OF PRECIP COULD COINCIDE WITH A LARGER COLD AIR SURGE INTO
THE SOUTH...AND THAT IS OF COURSE AN INTERESTING PROSPECT. BUT ANY
MEANINGFUL JUXTAPOSITION OF THOSE TWO ELEMENTS WOULD BE BEYOND THE
CURRENT LONG TERM PERIOD SO WE HAVE SOME MORE TIME TO LET MODEL
INCONGRUITIES LESSEN. /BB/
&&
.AVIATION...IFR CIGS AND MVFR VSBYS WILL BE THE RULE THROUGH THE
PERIOD AS AREAS OF LIGHT RAIN AND DRIZZLE CONTINUE OVER THE AREA.
CIGS MAY RISE TO MVFR AFTER 00Z IN THE GLH/GWO AREAS.
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 43 34 53 34 / 55 73 8 2
MERIDIAN 46 35 52 31 / 78 70 10 3
VICKSBURG 42 33 54 36 / 75 66 6 2
HATTIESBURG 48 36 55 34 / 63 51 8 2
NATCHEZ 43 34 55 36 / 69 56 7 2
GREENVILLE 42 32 53 35 / 94 51 6 2
GREENWOOD 41 31 53 34 / 82 65 7 2
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
349 AM EST FRI JAN 23 2015
.SYNOPSIS...HIGH PRESSURE WILL BUILD ACROSS VA AND NC THIS MORNING.
MEANWHILE...A LOW PRESSURE SYSTEM WILL TRACK JUST INLAND OF THE
SOUTHEAST US COAST THROUGH TONIGHT...THEN OFFSHORE THE MIDDLE
ATLANTIC AND NEW ENGLAND COAST ON SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM FRIDAY...
A POSITIVELY TILTED TROUGH OVER THE SOUTHERN PLAINS WILL CONTINUE
TO MOVE EAST ACROSS THE GULF COAST STATES TODAY AND THEN BEGIN TO
LIFT ACROSS THE CAROLINAS LATER TONIGHT. CYCLOGENESIS APPEARS TO BE
UNDERWAY SOUTH OF NEW ORLEANS THIS MORNING... AND THIS LOW FORECAST
IS TO TRACK ACROSS SOUTHERN GEORGIA AND UP THE CAROLINA COASTAL AREA
TONIGHT.
A LARGE AREA RAIN IS CURRENTLY SPREADING ACROSS ALABAMA AND
GEORGIA...WITH A FEW RADAR ECHOES AND TRACE REPORTS AS FAR EAST AS
AIKEN GEORGIA...BUT THE LEADING EDGE STILLS APPEARS TO BE DWINDLING
AS IT ENCOUNTERS THE DRIER AIR ASSOCIATED WITH A 1030MB SURFACE HIGH
CENTERED OVER SOUTHEAST VIRGINIA. THE HRRR HAS A PRETTY GOOD HANDLE
ON THIS AND SUGGESTS MEASURABLE PRECIP MAY REACH THE SOUTHERN
PIEDMONT BY 15Z. THE WETBULB FREEZING LINE IS CURRENTLY NEAR
HIGHWAY 64 AND SHOULDN`T MOVE MUCH MORE TO THE SOUTH AS MID CLOUDS
CONTINUE TO POUR IN FROM THE WEST AND TEMPS STABILIZE. RAP
SOUNDINGS SHOW JUST ENOUGH WARMING PRIOR TO THE ARRIVAL OF PRECIP TO
KEEP ALL PRECIP LIQUID AT ONSET.
ISENTROPIC LIFT REALLY INCREASES BY 18Z AND EXPECT RAIN TO BE
WIDESPREAD ACROSS THE ENTIRE AREA AFTER 21Z....WITH THE HEAVIEST
RAINFALL OCCURRING BETWEEN 00Z AND 06Z AS A 50KT LOW LEVEL JET
SURGES ACROSS CENTRAL AND EASTERN NC. THERE ARE STILL SOME
DIFFERENCE IN THE TRACK OF THE SURFACE LOW...THE ECMWF A GOOD 50 TO
75 MILES FURTHER INLAND THAN THE GFS. PREFERENCE IS FOR THE MORE
EASTERN TRACK OF THE GFS AND NAM GIVEN THAT A STRONG CAD AIRMASS
WILL DEVELOP IN RESPONSE TO THE RAIN THIS AFTERNOON. THE WEDGE FRONT
WILL LIKELY SHIFT INLAND AS THE LOW APPROACHES BUT THE TRUE WARM
SECTOR SHOULD REMAIN CONFINED TO THE COAST WHERE ANY SEVERE THREAT
WOULD ALSO REMAIN.
MODEL QPF IS RATHER HIGH TONIGHT...WITH AS MUCH AS ONE INCH IN THE
WEST AND NEAR 2 INCHES EAST OF I-95...AND THIS SEEMS VERY REASONABLE
GIVEN PW INCREASING TO AS MUCH AS 200 PERCENT OF NORMAL AND A
PLETHORA OF 1 TO 2 INCH TOTALS ALREADY REPORTED UPSTREAM ACROSS
LOUISIANA AND MISSISSIPPI. CONTEMPLATED A FLOOD WATCH GIVEN RECENT
RAINFALL EVENTS AND SOIL MOISTURE...BUT WITHOUT CONVECTION THE
FLOODING MAY MAY ISOLATED TO SOME OF THE SMALL CREEKS AND STREAMS
THAT ARE ALREADY RUNNING HIGHER THAN NORMAL. SOME MINOR RIVER
FLOODING IS ALSO POSSIBLE ON THE NEUSE AND TAR RIVERS.
TEMPS WILL RISE A LITTLE TODAY...MORE SO IN THE EAST...BUT AS PRECIP
MOVES IN THEY WILL LEVEL OFF OR EVEN DROP A BIT...WITH HIGHS INLY
REACHING THE MID 30S NORTHWEST TO MID 40S SOUTHEAST. TEMPS WON`T
CHANGE MUCH OVERNIGHT...DROPPING MAYBE 2 TO 3 DEGREES.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...
MODELS DEPICT A BRIEF PERIOD OF MID-LEVEL DRYING AS A DRY SLOT
SURGES ACROSS THE AREA LATE TONIGHT...BUT THE ARRIVAL OF THE UPPER
TROUGH AND STRONGER DCVA SHOULD CAUSE PRECIP TO REDEVELOP OR
REINTENSIFY EARLY SATURDAY...MAINLY ACROSS THE EASTERN HALF OF THE
AREA. RAINFALL TOTALS MAY NOT BE AS HIGH WITH THE SURFACE LOW
HAVING MOVED OFF TO THE NORTHEAST...BUT MODELS SHOW ANOTHER HALF
INCH POSSIBLE PRIOR TO 15Z. PRECIP WILL THEN END FOR MUCH OF THE
AREA AS MORE PRONOUNCED DRYING ALOFT DEVELOPS. HOWEVER... A
DEFORMATION BAND EXPECTED TO DEVELOP OVER THE TENNESSEE VALLEY WILL
PIVOT ACROSS AT LEAST THE NORTHERN HALF OF THE AREA AROUND MIDDAY.
RAPID MID-LEVEL COOLING AND RESATURATION OF THE ICE-NUCLEATION ZONE
SUGGESTS RAIN COULD MIX WITH OR CHANGE OVER TO SNOW WITHIN THIS
BAND...BUT FORECAST SOUNDINGS HAVE THE LOWEST 2000 FT OF THE
BOUNDARY LAYER ABOVE FREEZING AND THIS MAY BE TOO MUCH MELTING TO
OVERCOME. WILL BE INTERESTING TO SEE HOW THIS UNFOLDS...THOUGH NO
IMPACTS WOULD BE EXPECTED.
THE BAND SHOULD DEPART THE NORTHEAST CWA BY 18Z TO 21Z...WITH CLEAR
SKIES BY 00Z TO 03Z. COLD ADVECTION WILL BE RELATIVELY STRONG
SATURDAY EVENING...RESULTING WIND GUSTS OF 20-25MPH FOR THE FIRST
HALF OF THE NIGHT. LOWS WILL DROP INTO THE LOW TO MID 30S. -BLS
SUN AND SUN NIGHT: A STRONG PACIFIC JET WILL ROUND A WESTERN CONUS
RIDGE AND CAUSE AN ASSOCIATED NORTHERN STREAM SHORTWAVE TROUGH TO
AMPLIFY SHARPLY FROM THE NORTHERN PLAINS TO THE CAROLINAS AND VA
THROUGH SUN NIGHT. A CLIPPER SURFACE LOW WILL ACCOMPANY THE
SHORTWAVE TROUGH AND CROSS THE UPPER MIDWEST AND OH VALLEY SUN AND
THE CENTRAL APPALACHIANS AND MIDDLE ATLANTIC STATES SUN NIGHT. WSW
LOW LEVEL FLOW AHEAD OF THE CLIPPER LOW...AND IN BRIEF SHORTWAVE
RIDGING BETWEEN THIS SHORTWAVE TROUGH AND AN INTENSE CYCLONE
APPROACHING NOVA SCOTIA (OUR FRI-SAT WEATHER MAKER)...WILL RESULT IN
A MOSTLY SUNNY AND MILD DAY IN THE 50S TO END THE WEEKEND.
THE PASSAGE OF THE SHORTWAVE TROUGH AND ASSOCIATED COLD POOL ALOFT
CHARACTERIZED BY H5 TEMPERATURES AROUND MINUS 30 - AND POCKET OF MID
LEVEL LAPSE RATES AROUND 7 C/KM - WILL CAUSE AN AREA OF SHOWERS TO
PIVOT EAST ACROSS CENTRAL NC OVERNIGHT. ALL LIQUID IS ANTICIPATED
OWING TO A 1500-3000 FT DEEP ABOVE FREEZING BOUNDARY LAYER...LOWEST
AND COLDEST ONCE THE SHOWERS ARE MOVING OUT. LOWS...AND WITH
CLEARING SPREADING INTO THE PIEDMONT BY DAYBREAK...WITHIN A FEW
DEGREES EITHER SIDE OF 35. -MWS
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 345 AM FRIDAY...
JUST AS QUICKLY AS THE CLOUDINESS AND SHOWERS ASSOCIATED WITH THE
"ALBERTA CLIPPER"/NORTHERN STREAM SHORTWAVE WAVE MOVE OUT...
ADDITIONAL SHEAR VORTICITY IN FAST NW FLOW ALOFT WILL AMPLIFY INTO
THE TROUGH BASE...TO NEAR AND JUST OFFSHORE THE COAST OF THE
CAROLINAS...THROUGH WED MORNING. TYPICAL MEDIUM RANGE TIMING AND
AMPLITUDE DISTANCES BECOME MAGNIFIED DURING THIS TIME...WITH THE 00Z
ECMWF REPRESENTING THE SOUTHERNMOST - AND CONSEQUENTLY RELATIVELY
WETTEST FOR CENTRAL NC - SOLUTIONS FOR THE PERIOD MON-TUE. BASED ON
A PREFERRED SLIGHTLY LESS AMPLIFIED/MORE NORTHWARD CONSENSUS OF
MODEL CLUSTERING REPRESENTED WELL BY THE 00Z GFS...THE RELATIVE
HIGHEST PROBABILITY OF PRECIPITATION (IN THE CHANCE RANGE) SHOULD BE
CENTERED TOWARD THE NORTHEAST PIEDMONT WITH THE ARRIVAL OF THE LEAD
SHEAR VORTICITY AND POSSIBLE INTERACTION WITH A LOW LEVEL MOIST AXIS
OVER EASTERN NC THROUGH MON NIGHT. ANY PRECIPITATION THAT WERE TO
FALL AFTER DARK MON...AFTER TEMPERATURES PEAK IN THE UPPER 40S TO
LOWER 50S...WOULD BE IN THE FORM OF LIGHT SNOW OWING TO STRONG DEEP
LAYER COOLING MON NIGHT - A CASE OF "THE COLD AIR CHASING THE
MOISTURE".
TRAILING SHEAR VORTICITY WILL CARVE THE TROUGH OFF THE COAST OF THE
CAROLINAS TUE-TUE NIGHT. ASSOCIATED RE-STEEPENING OF THE LAPSE RATES
ALOFT...AND LIFT/MOISTENING OF THE COLUMN...WILL RESULT IN YET
ANOTHER SLIGHT TO CHANCE OF RAIN SHOWERS - OR SNOW SHOWERS WHERE/IF
THE SUB-CLOUD LAYER FULLY WET-BULBS AND THEORETICALLY "MELTS OUT" A
PROJECTED 1500-2000 FT ABOVE FREEZING BOUNDARY LAYER. THE REMAINDER
OF THE LONG TERM WILL BE DRY AND CHILLY... PARTICULARLY WITH RESPECT
TO LOWS BOTH WED AND THU MORNINGS...AS MODIFIED ARCTIC HIGH PRESSURE
DRIFTS OVERHEAD IN THE WAKE OF THE TROUGH AXIS MOVING AWAY FROM THE
NC COAST.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 145 AM FRIDAY...
VFR CONDITIONS...UNDER THE INFLUENCE OF CONTINENTAL POLAR HIGH
PRESSURE BUILDING EAST ACROSS THE VIRGINIAS THIS MORNING...WILL
PREVAIL UNTIL MIDDAY-EARLY AFTERNOON...AT WHICH TIME LIFT AND
MOISTURE WILL HAVE SUFFICIENTLY INCREASED AND CAUSED RAIN AND
ASSOCIATED MVFR CEILINGS AND VISIBILITIES TO OVERSPREAD OUR AREA
DOWNSTREAM OF A STORM SYSTEM APPROACHING FROM THE NORTHERN GULF OF
MEXICO. RAIN INTENSITY WILL FURTHER INCREASE...AND AVIATION
CONDITIONS FURTHER DETERIORATE TO LIFR-IFR...THROUGH THE AFTERNOON
AND EVENING. IN ADDITION...THE ARRIVAL OF AN EAST SOUTHEASTERLY TO
SOUTHERLY LOW LEVEL JET AT 2000 FT...ATOP MUCH LIGHTER EASTERLY
WINDS AT THE SURFACE...WILL PROMOTE A LIKELY PROBABILITY OF LOW
LEVEL WIND SHEAR CONDITIONS AT EASTERN TERMINALS ROUGHLY BETWEEN 22-
04Z. PERIODS OF RAIN AND DRIZZLE...AND LIFR CONDITIONS...WILL
CONTINUE OVERNIGHT...AS THE LOW PRESSURE SYSTEM TRACKS JUST INLAND
OF THE COAST OF THE CAROLINAS.
OUTLOOK: SHOWERS WILL LINGER THROUGH MIDDAY SAT...WHILE CEILINGS AND
VISIBILITIES GRADUALLY RISE THROUGH MVFR RANGE...TO VFR BY
AFTERNOON...AS THE LOW PRESSURE SYSTEM TRACKS UP THE MIDDLE ATLANTIC
COAST AND AWAY FROM CENTRAL NC. A COUPLE OF UPPER LEVEL DISTURBANCES
WILL BRING A RENEWED CHANCE OF BRIEF SUB-VFR CONDITIONS AND RAIN
SHOWERS TO THE AREA LATE SUN NIGHT-MON....AND POSSIBLY AGAIN ON TUE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...BLS
SHORT TERM...BLS/MWS
LONG TERM...MWS
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
335 AM EST FRI JAN 22 2015
.SYNOPSIS...HIGH PRESSURE WILL BUILD ACROSS VA AND NC THIS MORNING.
MEANWHILE...A LOW PRESSURE SYSTEM WILL TRACK JUST INLAND OF THE
SOUTHEAST US COAST THROUGH TONIGHT...THEN OFFSHORE THE MIDDLE
ATLANTIC AND NEW ENGLAND COAST ON SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM FRIDAY...
A POSITIVELY TILTED TROUGH OVER THE SOUTHERN PLAINS WILL CONTINUE
TO MOVE EAST ACROSS THE GULF COAST STATES TODAY AND THEN BEGIN TO
LIFT ACROSS THE CAROLINAS LATER TONIGHT. CYCLOGENESIS APPEARS TO BE
UNDERWAY SOUTH OF NEW ORLEANS THIS MORNING... AND THIS LOW FORECAST
IS TO TRACK ACROSS SOUTHERN GEORGIA AND UP THE CAROLINA COASTAL AREA
TONIGHT.
A LARGE AREA RAIN IS CURRENTLY SPREADING ACROSS ALABAMA AND
GEORGIA...WITH A FEW RADAR ECHOES AND TRACE REPORTS AS FAR EAST AS
AIKEN GEORGIA...BUT THE LEADING EDGE STILLS APPEARS TO BE DWINDLING
AS IT ENCOUNTERS THE DRIER AIR ASSOCIATED WITH A 1030MB SURFACE HIGH
CENTERED OVER SOUTHEAST VIRGINIA. THE HRRR HAS A PRETTY GOOD HANDLE
ON THIS AND SUGGESTS MEASURABLE PRECIP MAY REACH THE SOUTHERN
PIEDMONT BY 15Z. THE WETBULB FREEZING LINE IS CURRENTLY NEAR
HIGHWAY 64 AND SHOULDN`T MOVE MUCH MORE TO THE SOUTH AS MID CLOUDS
CONTINUE TO POUR IN FROM THE WEST AND TEMPS STABILIZE. RAP
SOUNDINGS SHOW JUST ENOUGH WARMING PRIOR TO THE ARRIVAL OF PRECIP TO
KEEP ALL PRECIP LIQUID AT ONSET.
ISENTROPIC LIFT REALLY INCREASES BY 18Z AND EXPECT RAIN TO BE
WIDESPREAD ACROSS THE ENTIRE AREA AFTER 21Z....WITH THE HEAVIEST
RAINFALL OCCURRING BETWEEN 00Z AND 06Z AS A 50KT LOW LEVEL JET
SURGES ACROSS CENTRAL AND EASTERN NC. THERE ARE STILL SOME
DIFFERENCE IN THE TRACK OF THE SURFACE LOW...THE ECMWF A GOOD 50 TO
75 MILES FURTHER INLAND THAN THE GFS. PREFERENCE IS FOR THE MORE
EASTERN TRACK OF THE GFS AND NAM GIVEN THAT A STRONG CAD AIRMASS
WILL DEVELOP IN RESPONSE TO THE RAIN THIS AFTERNOON. THE WEDGE FRONT
WILL LIKELY SHIFT INLAND AS THE LOW APPROACHES BUT THE TRUE WARM
SECTOR SHOULD REMAIN CONFINED TO THE COAST WHERE ANY SEVERE THREAT
WOULD ALSO REMAIN.
MODEL QPF IS RATHER HIGH TONIGHT...WITH AS MUCH AS ONE INCH IN THE
WEST AND NEAR 2 INCHES EAST OF I-95...AND THIS SEEMS VERY REASONABLE
GIVEN PW INCREASING TO AS MUCH AS 200 PERCENT OF NORMAL AND A
PLETHORA OF 1 TO 2 INCH TOTALS ALREADY REPORTED UPSTREAM ACROSS
LOUISIANA AND MISSISSIPPI. CONTEMPLATED A FLOOD WATCH GIVEN RECENT
RAINFALL EVENTS AND SOIL MOISTURE...BUT WITHOUT CONVECTION THE
FLOODING MAY MAY ISOLATED TO SOME OF THE SMALL CREEKS AND STREAMS
THAT ARE ALREADY RUNNING HIGHER THAN NORMAL. SOME MINOR RIVER
FLOODING IS ALSO POSSIBLE ON THE NEUSE AND TAR RIVERS.
TEMPS WILL RISE A LITTLE TODAY...MORE SO IN THE EAST...BUT AS PRECIP
MOVES IN THEY WILL LEVEL OFF OR EVEN DROP A BIT...WITH HIGHS INLY
REACHING THE MID 30S NORTHWEST TO MID 40S SOUTHEAST. TEMPS WON`T
CHANGE MUCH OVERNIGHT...DROPPING MAYBE 2 TO 3 DEGREES.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...
MODELS DEPICT A BRIEF PERIOD OF MID-LEVEL DRYING AS A DRY SLOT
SURGES ACROSS THE AREA LATE TONIGHT...BUT THE ARRIVAL OF THE UPPER
TROUGH AND STRONGER DCVA SHOULD CAUSE PRECIP TO REDEVELOP OR
REINTENSIFY EARLY SATURDAY...MAINLY ACROSS THE EASTERN HALF OF THE
AREA. RAINFALL TOTALS MAY NOT BE AS HIGH WITH THE SURFACE LOW
HAVING MOVED OFF TO THE NORTHEAST...BUT MODELS SHOW ANOTHER HALF
INCH POSSIBLE PRIOR TO 15Z. PRECIP WILL THEN END FOR MUCH OF THE
AREA AS MORE PRONOUNCED DRYING ALOFT DEVELOPS. HOWEVER... A
DEFORMATION BAND EXPECTED TO DEVELOP OVER THE TENNESSEE VALLEY WILL
PIVOT ACROSS AT LEAST THE NORTHERN HALF OF THE AREA AROUND MIDDAY.
RAPID MID-LEVEL COOLING AND RESATURATION OF THE ICE-NUCLEATION ZONE
SUGGESTS RAIN COULD MIX WITH OR CHANGE OVER TO SNOW WITHIN THIS
BAND...BUT FORECAST SOUNDINGS HAVE THE LOWEST 2000 FT OF THE
BOUNDARY LAYER ABOVE FREEZING AND THIS MAY BE TOO MUCH MELTING TO
OVERCOME. WILL BE INTERESTING TO SEE HOW THIS UNFOLDS...THOUGH NO
IMPACTS WOULD BE EXPECTED.
THE BAND SHOULD DEPART THE NORTHEAST CWA BY 18Z TO 21Z...WITH CLEAR
SKIES BY 00Z TO 03Z. COLD ADVECTION WILL BE RELATIVELY STRONG
SATURDAY EVENING...RESULTING WIND GUSTS OF 20-25MPH FOR THE FIRST
HALF OF THE NIGHT. LOWS WILL DROP INTO THE LOW TO MID 30S. -BLS
SUN AND SUN NIGHT: A STRONG PACIFIC JET WILL ROUND A WESTERN CONUS
RIDGE AND CAUSE AN ASSOCIATED NORTHERN STREAM SHORTWAVE TROUGH TO
AMPLIFY SHARPLY FROM THE NORTHERN PLAINS TO THE CAROLINAS AND VA
THROUGH SUN NIGHT. A CLIPPER SURFACE LOW WILL ACCOMPANY THE
SHORTWAVE TROUGH AND CROSS THE UPPER MIDWEST AND OH VALLEY SUN AND
THE CENTRAL APPALACHIANS AND MIDDLE ATLANTIC STATES SUN NIGHT. WSW
LOW LEVEL FLOW AHEAD OF THE CLIPPER LOW...AND IN BRIEF SHORTWAVE
RIDGING BETWEEN THIS SHORTWAVE TROUGH AND AN INTENSE CYCLONE
APPROACHING NOVA SCOTIA (OUR FRI-SAT WEATHER MAKER)...WILL RESULT IN
A MOSTLY SUNNY AND MILD DAY IN THE 50S TO END THE WEEKEND.
THE PASSAGE OF THE SHORTWAVE TROUGH AND ASSOCIATED COLD POOL ALOFT
CHARACTERIZED BY H5 TEMPERATURES AROUND MINUS 30 - AND POCKET OF MID
LEVEL LAPSE RATES AROUND 7 C/KM - WILL CAUSE AN AREA OF SHOWERS TO
PIVOT EAST ACROSS CENTRAL NC OVERNIGHT. ALL LIQUID IS ANTICIPATED
OWING TO A 1500-3000 FT DEEP ABOVE FREEZING BOUNDARY LAYER...LOWEST
AND COLDEST ONCE THE SHOWERS ARE MOVING OUT. LOWS...AND WITH
CLEARING SPREADING INTO THE PIEDMONT BY DAYBREAK...WITHIN A FEW
DEGREES EITHER SIDE OF 35. -MWS
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 150 PM THURSDAY...
LATE WEEKEND THROUGH NEXT WEEK WILL FEATURE HIGHLY AMPLIFIED MID
LEVEL FLOW AND COOLER TEMPERATURES AFTER A BRIEF PERIOD OF
SUBSIDENCE ON SUNDAY WHICH WILL ALLOW TEMPS TO REACH THE UPPER 40S
AND LOWER 50S. IN THE ENSUING NORTHWEST FLOW REGIME...AN INITIAL
SHORT WAVE WILL BE DIVING SOUTHEAST THROUGH THE OHIO VALLEY SUNDAY
NIGHT...GRAZING NORTH CAROLINA ON MONDAY. THIS WILL BE FOLLOWED
QUICKLY BY ANOTHER REINFORCING IMPULSE ON TUESDAY...BUT DETAILS AND
TIMING ISSUES THROW A LOT OF UNCERTAINTY INTO THE FORECAST AT THIS
POINT. THESE TWO SYSTEMS WILL BE LIMITED TO THE MOISTURE THAT THEY
BRING WITH THEM...WHICH WILL PRODUCE WIDESPREAD CLOUDINESS...BUT
ONLY LOW PRECIP CHANCES AND AT THIS POINT WILL BE LIMITING POPS TO
AROUND 30 PERCENT ACROSS THE NORTHERN TIER. IF SUFFICIENT MOISTURE
WITH THE INITIAL SHORT WAVE ARRIVES SUNDAY NIGHT THERE COULD BE SOME
LIGHT MIXED PRECIP ACROSS THE NORTHERN TIER IN THE PRE-DAWN TO EARLY
MONDAY MORNING BEFORE TEMPERATURES NEAR FREEZING WARM INTO THE UPPER
30S BY MID MORNING. WILL HAVE A SMALL POP FOR RAIN SHOWERS ON MONDAY
AREA-WIDE WITH HIGHS FROM THE MID 40S NORTH TO PERHAPS SOME LOWER
50S SOUTHEAST.
COLD AIR ADVECTION BEHIND THIS SHORT WAVE WILL KICK IN MONDAY NIGHT
AND MINS WILL FALL INTO THE UPPER 20S NORTH TO AROUND FREEZING
SOUTH. THERE IS LESS CONFIDENCE WITH TIMING BUT ALSO LESS POTENTIAL
FOR PRECIP WITH THE SECOND IMPULSE DIGGING TOWARDS THE AREA ON
MONDAY NIGHT AND TUESDAY. AT THIS POINT WILL MAINTAIN ONGOING SLIGHT
CHANCE POPS LIMITED TO MONDAY NIGHT. IF WE GET PRECIP...THERE COULD
BE A CHANGE OVER TO A MIXTURE OF VERY LIGHT RAIN AND SNOW SHOWERS AS
TEMPS FALL BELOW FREEZING MONDAY NIGHT. WILL KEEP POPS OUT OF THE
FORECAST TUESDAY FOR NOW GIVEN INCREASING UNCERTAINTY WITH TIME IN
THE NORTHWEST FLOW PATTERN. TUESDAY HIGHS WILL BE FROM 40 TO 45.
THE UPPER TROF SHIFTS OFFSHORE BY LATE WEDNESDAY...WITH A SLIGHT
WARMUP EXPECTED TOWARDS LATE WEEK AS HEIGHTS INCREASE WITH RIDGING
ALOFT AND PLENTIFUL SUNSHINE ON THURSDAY. HIGHS WEDNESDAY WILL
STRUGGLE TO GET OUT OF THE MID 40S...WARMING TO THE UPPER 40S TO
LOWER 50S THURSDAY...WHICH IS ONLY SLIGHTLY BELOW NORMAL.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 145 AM FRIDAY...
VFR CONDITIONS...UNDER THE INFLUENCE OF CONTINENTAL POLAR HIGH
PRESSURE BUILDING EAST ACROSS THE VIRGINIAS THIS MORNING...WILL
PREVAIL UNTIL MIDDAY-EARLY AFTERNOON...AT WHICH TIME LIFT AND
MOISTURE WILL HAVE SUFFICIENTLY INCREASED AND CAUSED RAIN AND
ASSOCIATED MVFR CEILINGS AND VISIBILITIES TO OVERSPREAD OUR AREA
DOWNSTREAM OF A STORM SYSTEM APPROACHING FROM THE NORTHERN GULF OF
MEXICO. RAIN INTENSITY WILL FURTHER INCREASE...AND AVIATION
CONDITIONS FURTHER DETERIORATE TO LIFR-IFR...THROUGH THE AFTERNOON
AND EVENING. IN ADDITION...THE ARRIVAL OF AN EAST SOUTHEASTERLY TO
SOUTHERLY LOW LEVEL JET AT 2000 FT...ATOP MUCH LIGHTER EASTERLY
WINDS AT THE SURFACE...WILL PROMOTE A LIKELY PROBABILITY OF LOW
LEVEL WIND SHEAR CONDITIONS AT EASTERN TERMINALS ROUGHLY BETWEEN 22-
04Z. PERIODS OF RAIN AND DRIZZLE...AND LIFR CONDITIONS...WILL
CONTINUE OVERNIGHT...AS THE LOW PRESSURE SYSTEM TRACKS JUST INLAND
OF THE COAST OF THE CAROLINAS.
OUTLOOK: SHOWERS WILL LINGER THROUGH MIDDAY SAT...WHILE CEILINGS AND
VISIBILITIES GRADUALLY RISE THROUGH MVFR RANGE...TO VFR BY
AFTERNOON...AS THE LOW PRESSURE SYSTEM TRACKS UP THE MIDDLE ATLANTIC
COAST AND AWAY FROM CENTRAL NC. A COUPLE OF UPPER LEVEL DISTURBANCES
WILL BRING A RENEWED CHANCE OF BRIEF SUB-VFR CONDITIONS AND RAIN
SHOWERS TO THE AREA LATE SUN NIGHT-MON....AND POSSIBLY AGAIN ON TUE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...BLS
SHORT TERM...BLS/MWS
LONG TERM...MLM
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1245 AM CST FRI JAN 23 2015
.UPDATE...
ISSUED AT 1245 AM CST FRI JAN 23 2015
MID LEVEL S/WV TROUGH MOVING SOUTHEAST ACROSS FAR SOUTH CENTRAL
CANADA WITH ITS ASSOCIATED SFC TROUGH STRETCHED ACROSS
NORTHEASTERN ND SOUTHWEST THROUGH SOUTH CENTRAL NORTH DAKOTA.
ENHANCED FORCING NEAR THE MID LEVEL WAVE DEVELOPING PRECIPITATION
ACROSS THE NORTH CENTRAL AND EASTERN PARTS OF THE STATE EARLY THIS
MORNING...WITH THE HIGHER RADAR RETURNS FROM DEVILS LAKE TO GRAND
FORKS. AIR TEMPERATURES GENERALLY 34-39F WHERE RADAR RETURNS ARE.
HOWEVER...SURFACE/GROUND TEMPERATURES BELOW FREEZING SO ANY
PRECIPITATION THAT IS REACHING THE GROUND WILL FREEZE ON CONTACT.
WITH LACK OF DECENT REFLECTIVITIES OPTED TO HIGHLIGHT THE FREEZING
RAIN POSSIBILITY WITH A SPECIAL WEATHER STATEMENT FOR NOW.
PRECIPITATION WILL CONTINUE SOUTH AND SHOULD EXIT THE LOCAL AREA
BY 12Z.
MAIN UPDATES WERE TO POPS...EXPANDING THEM A BIT BUT LEFT AT
SLIGHT CHANCE...AND BUMPED TEMPS UP A TAD.
UPDATE ISSUED AT 957 PM CST THU JAN 22 2015
QUICK UPDATE FOR POPS BASED ON CURRENT RADAR...KEPT A LITTLE
HIGHER POPS NORTH CENTRAL THROUGH THE EVENING AND INTO THE EARLY
OVERNIGHT HOURS. LATEST RAP SHOWS PRECIP HOLDING ON THROUGH AROUND
06-07 UTC WHICH AGREES WITH CURRENT FORECAST. LATEST HRRR HOLDS
PRECIP TOGETHER A LITTLE LONGER AND DROPS IT FARTHER SOUTH. IF
THIS WOULD HOLD TRUE AND PRECIP DOES NOT EVAPORATE...WE COULD SEE
A FEW FREEZING SPRINKLES OR LIGHT FREEZING RAIN AS REFLECTIVITIES
DROP SOUTH TOWARD GARRISON...HARVEY AND CARRINGTON. THATS A BIG
IF...AND WOULD STILL BE TALKING ABOUT ONLY TRACE AMOUNTS. WILL
KEEP ANY ACCUMULATING PRECIP CONFINED TO THE NORTH CENTRAL FOR NOW
AND PASS ALONG TO THE OVERNIGHT SHIFT.
UPDATE ISSUED AT 842 PM CST THU JAN 22 2015
SHOWERS HAVE INTENSIFIED ACROSS SOUTHWEST MB INTO NORTH CENTRAL
NORTH DAKOTA THIS EVENING AND HAVE BUMPED UP POPS FROM AROUND
SHERWOOD EAST THROUGH BOTTINEAU AND THE TURTLE MOUNTAINS TO
BELCOURT. QUITE A BIT OF DRY AIR BELOW THE PRECIPITATION AND
QUICK MOVEMENT WILL LIKELY YIELD MAINLY TRACE AMOUNTS. A FEW AREAS
COULD SEE A HUNDREDTH OR TWO. WARM FRONT HAS PUSHED INTO NORTHEAST
NORTH DAKOTA THUS TEMPERATURES ARE MAINLY IN THE MID 30S...AND
SHOULD REMAIN STEADY WITH A MODERATE WEST TO SOUTHWEST SURFACE
FLOW. AT THIS TIME IT LOOKS LIKE MAINLY SPRINKLES/RAIN SHOWERS.
WITH A SMALL PROBABILITY OF SOME LIGHT FREEZING RAIN AROUND
MIDNIGHT...BEFORE PRECIP TAPERS OFF AND MOVES EAST.
UPDATE ISSUED AT 605 PM CST THU JAN 22 2015
NO SIGNIFICANT UPDATES TO THE EARLY EVENING FORECAST. SURFACE LOW
TRACKING EAST ACROSS SOUTHERN CANADA. VERY LIGHT PRECIPITATION
EXTENDING FROM BRANDON SOUTHWEST TO WEYBURN AND JUST CLIPPING THE
INTERNATIONAL BORDER FROM CROSBY TO SHERWOOD. CURRENT TEMPERATURES
ARE ABOVE FREEZING AND EXPECTED PRECIPITATION WILL BE MAINLY TRACE
AMOUNTS. AT THIS TIME NO SIGNIFICANT HAZARDS EXPECTED...BUT WILL
MAINTAIN A SLIGHT CHANCE OF A MIX OF RAIN...SNOW AND FREEZING RAIN
ACROSS THE FAR NORTH EARLY THIS EVENING AND THEN DROPPING
SOUTHEAST INTO THE JAMES RIVER VALLEY LATER TONIGHT. UPDATED TEXT
PRODUCTS OUT SHORTLY.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 310 PM CST THU JAN 22 2015
CURRENT SURFACE ANALYSIS PLACES LOW PUSHING THROUGH NORTHERN
MANITOBA WITH HIGH OVER THE GREAT BASIN. UPPER LEVEL ANALYSIS
PLACES RIDGE OVER THE WESTERN CONUS WITH A WEAK SHORTWAVE MOVING
THROUGH SOUTHERN SASKATCHEWAN INTO CENTRAL MONTANA. A FEW LIGHT
SHOWERS HAVE DEVELOPED OVER SOUTHERN SASKATCHEWAN/MANITOBA WITH
THIS SYSTEM.
FOR TONIGHT...AFOREMENTIONED SHORT WAVE MOVES THROUGH THE AREA
WHICH WILL BRING PRECIPITATION CHANCES MAINLY TO NORTHERN INTO
CENTRAL NORTH DAKOTA...THOUGH THE WAVE IS QUITE WEAK SO WILL LEAVE
CHANCES ON THE LOW SIDE. SOUNDING ANALYSIS SUGGESTS MAINLY RAIN
WITH THIS SYSTEM...WHICH COULD LEAD TO SOME FREEZING RAIN IF IT IS
PRECIPITATING WHEN TEMPS DROP BELOW FREEZING. SKIES WILL START
CLEARING IN THE WAKE OF THE WAVE AS IT PASSES THROUGH LATE TONIGHT.
ON FRIDAY...QUIET WEATHER IS EXPECTED AS UPPER RIDGE TO THE WEST
CONTINUES TO BE THE DOMINATE FEATURE AND REGION IS BETWEEN SYSTEM.
TEMPERATURES WILL REMAIN QUITE MILD.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 352 PM CST THU JAN 22 2015
ABOVE NORMAL TEMPERATURES AND SLIGHT CHANCES RAIN...FREEZING RAIN
AND SNOW HIGHLIGHT THE EXTENDED FORECAST.
AN UPPER LEVEL RIDGE ACROSS THE WEST COAST WILL REMAIN IN PLACE
THROUGH EARLY NEXT WEEK. THIS WILL KEEP THE MAJORITY OF THE ARCTIC
AIR BOTTLED UP AROUND THE HUDSON BAY. FOR OUR AREA TEMPERATURES
WILL GENERALLY RANGE FROM THE 30S ACROSS THE EASTERN JAMES VALLEY
AND UPPER 40S ACROSS WESTERN NORTH DAKOTA. TEMPERATURES IN THE 50S
ARE POSSIBLE EARLY NEXT WEEK.
SEVERAL WEAK CLIPPERS WILL SWING THROUGH THE AREA DURING THE
EXTENDED PERIOD. THE FIRST SUCH CLIPPER IS EXPECTED TO AFFECT THE
AREA SATURDAY INTO SUNDAY...WITH THE OTHER TWO ARRIVING MONDAY AND
THURSDAY.
FOR SATURDAY INTO SUNDAY...LATEST GUIDANCE SEEMS TO HAVE TAKEN A STEP
BACKWARD AS FAR AS CONSISTENCY AND AGREEMENT ARE CONCERNED. THE 12
UTC ECMWF IS MORE PROGRESSIVE AND BULLISH WITH QPF AMOUNTS ACROSS
WESTERN AND CENTRAL NORTH DAKOTA. WHEREAS THE GFS AND SREF ARE
SLOWER AND MAINLY DRY. THE NAM INITIALLY KEEPS PRECIP OUT OF THE
AREA AS THE CLIPPER SLIDES ACROSS EASTERN NORTH DAKOTA...BUT THEN
BRINGS SOME WRAP-AROUND PRECIP INTO WESTERN NORTH DAKOTA. DUE TO
THE WIDE RANGE OF MODEL SOLUTIONS CONFIDENCE ON ANY PARTICULAR
SCENARIO IS RATHER LOW. THEREFORE...KEPT PRECIP CHANCES BELOW 25
PERCENT THROUGH SUNDAY. LOOKING AT FORECAST SOUNDING PROFILES IT
WOULD APPEAR THAT THE MOST FAVORED PRECIP TYPE (IF PRECIPITATION
DOES IN FACT FORM) WOULD BE RAIN ACROSS THE MAJORITY OF THE AREA.
WITH COOLER TEMPERATURES ALOFT AND AT THE SURFACE FURTHER EAST...A
MIX OF FREEZING DRIZZLE OR SNOW FLURRIES ARE POSSIBLE ALONG AND
EAST OF HWY 281. WITH QPF AMOUNTS EXPECTED TO BE LIGHT...OR
POTENTIALLY NONEXISTENT DEPENDING ON WHAT GUIDANCE YOU
BELIEVE...IMPACTS SHOULD BE MINIMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1245 AM CST FRI JAN 23 2015
A BAND OF LIGHT PRECIPITATION FROM NEAR MINOT TO GRAND FORKS WILL
DROP SOUTHEAST TONIGHT. AIR TEMPERATURES ARE IN THE MID 30S TO
AROUND 40 DEGREES UNTIL PRECIPITATION PASSES...AND PRECIPITATION IS
VERY LIGHT SO JUST MENTIONED A VCSH AT KMOT THROUGH 09 UTC AND AT
KJMS FROM 07-10 UTC WITH A VFR CEILING AROUND 9000 FEET. OTHERWISE
VFR MID AND HIGH LEVEL CLOUDS THROUGH THE FORECAST PERIOD WITH A
MODERATE WEST TO NORTHWEST FLOW.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...JJS
LONG TERM...AJ
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
327 AM EST FRI JAN 23 2015
.SYNOPSIS...
STRENGTHENING LOW PRESSURE ACROSS SOUTHEAST TODAY AND OFF NEW
ENGLAND COAST SATURDAY. CLIPPER LATE SUNDAY/SUNDAY NIGHT. TURNING
COLDER MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
ALL ON EYES ON SURFACE LOW TRAVERSING THRU THE SE STATES
TODAY...FOLLOWED BY AN UPPER TROF AXIS CROSSING THE REGION
OVERNIGHT. THERE ARE A NUMBER OF MITIGATING FACTORS THAT WILL KEEP
THE WINTRY EFFECTS FROM THIS MINIMAL. A LACK OF A SURFACE HIGH TO
THE N...MARGINAL COLD AIR ALOFT...AND A PESKY INVERTED SURFACE TROF
OVER THE AREA...ALL POINT TO MORE OF A NUISANCE EVENT.
AS FOR THE NITTY GRITTY DETAILS...
SPED UP POPS A BIT FROM PREVIOUS FORECAST...PRIMARILY USING THE HRRR
TIMING. A RELATIVELY DEEP DOWNSLOPING SSE TO SE FLOW INTO MIDDAY MAY
GIVE TEMPS A SPIKE. HOWEVER...NONE OF THE MODELS ARE SHOWING THIS
EXCEPT HRRR AND RUC. SO KEPT HIGHS IN CHECK BUT STILL A FEW DEGREES
ABOVE GUIDANCE FROM ALONG US119 AND I79 CORRIDOR OVER TO W SLOPES.
THERMAL PROFILES FROM VARIOUS HI RES MODELS INDICATED PRECIP
STARTING AS RAIN OUTSIDE OF THE MOUNTAINS. PRECIP SHOULD START OUT
AS SNOW OR A MIX OF SNOW AND SLEET IN THE MOUNTAINS...WHERE A FEW
INCHES WERE CODED UP FOR LATE THIS AFTERNOON.
THIS EVENING...THE STEADY PRECIP WILL HAVE SHIFTED INTO SE OH AND N
WV WITH SCT COVERAGE IN THE MID LEVEL DRY PUNCH ELSEWHERE. THE
SURFACE LOW WILL BE MAKING A RUN OFF THE TIDEWATER REGION WITH THE
INVERTED SURFACE TROF LINGERING OVER THE AREA. MODEL SOUNDINGS SHOW
A WARM LAYER ALOFT ACROSS THE MOUNTAINS...DEEP ENOUGH FOR THE PRECIP
TO CHANGE TO FREEZING RAIN ACROSS THE ELEVATION ABOVE 3.5KFT...WITH
SOME SLEET EXPECTED OVER THE TYGART AND ESPECIALLY THE GREENBRIER
VALLEY. IT IS EVEN POSSIBLE SNOWSHOE CHANGES TO LIGHT RAIN FOR A
TIME. MEANWHILE...THE CHANGEOVER TO WET SNOW WILL BE OCCURRING
ACROSS NE KY AND SE OH AS THE UPPER TROF AXIS CLOSES IN WITH COOLING
ALOFT. THERE CONTINUES TO BE A DEFORMATION BAND OF SORTS SHOWING UP
ON THE MODELS AS THE UPPER TROF CROSSES. HAVE ORIENTED THE POPS TO
REFLECT THIS THINKING...SLOWLY TRACKING IT E FROM SE OH/NE KY INTO C
WV BY PREDAWN HRS. THIS SHOULD COINCIDE WITH THE CHANGEOVER TO WET
SNOW. HAVE ALLOWED AROUND AN INCH TO FALL ACROSS SE OH/NE KY/W WV
WITH A COATING FURTHER E AS THE OVERALL BAND BEGINS TO WEAKEN.
ACROSS THE MOUNTAINS...PRECIP WILL CHANGE BACK TO SNOW AFTER
MIDNIGHT BUT PRECIP SHOULD BE SPOTTY UNTIL THE UPPER TROF AXIS AND
DEFORMATION BAND MOVES IN TOWARD MORNING.
AFTER COLLABORATION WITH SURROUNDING OFFICES...HAVE HOISTED A WINTER
WEATHER ADVISORY FOR RANDOLPH AND POCAHONTAS. DESPITE NOT REACHING
CRITERIA SNOW WISE...THERE IS EXPECTED TO BE SOME FREEZING RAIN IN
THE HIGHER ELEVATIONS WHICH MAY ACCRUE TO AROUND A TENTH OF AN
INCH. STARTED IT THIS AFTERNOON TO HIT THE INITIAL LIGHT
ACCUMULATION OF SNOW WITH THE ICE THREAT FROM 00 TO 06Z. ENDED IT AT
15Z WHEN THE UPPER TROF IS EXPECTED TO HAVE MOVED THRU.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
MODELS SHOW SYSTEM PULLING OUT EARLY SATURDAY. SOME MARGINAL UPSLOPE
THEN APPEARS POSSIBLE SATURDAY NIGHT AS NORTHWEST WINDS PULL IN SOME
COOLER AIR. 850 MB TEMPERATURES ARE MARGINAL FOR AUTO CONVECTION IN
THE LOWER LEVELS...SO WILL KEEP POPS IN THE CHANCE CATEGORY.
MODELS ARE A BIT FASTER WITH A CLIPPER MOVING THROUGH LATE
SUNDAY/SUNDAY EVENING. BOTH NAM AND GFS ARE SHOWING LOTS OF LIFT
WELL SOUTH OF THE LOW TRACK...BUT CLIPPERS USUALLY STRUGGLE TO
PRODUCE PRECIPITATION SOUTH OF THE LOW. THEREFORE...WILL SHOW A
NORTH SOUTH GRADIENT OF POPS.
COLDER AIR BEHIND THE CLIPPER ON MONDAY IS COLD ENOUGH FOR AUTO
CONVECTIVE CONDITIONS IN THE LOWER LEVELS...SO WILL KEEP HIGH POPS
OF SNOW.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
THE TREND THAT WE MENTIONED YESTERDAY REMAINS...THE CLIPPER COMING
EAST THROUGH THE MIDWEST INTO THE UPPER OHIO VALLEY...AT A HIGHER
LATITUDE REMAINS. AS A RESULT...WAS A BIT SLOWER BRINGING IN THE
COLDER AIR LATE SUNDAY NIGHT INTO MONDAY. POPS INCREASE NW TO SE
DURING SUNDAY NIGHT IN THE WAKE OF THE CLIPPER PASSING OUR LONGITUDE.
WE WILL BE CONSISTENT WITH POPS IN THE LIKELY CATEGORY MONDAY INTO
MONDAY EVENING BEFORE WANING FROM WEST TO EAST. AS MOISTURE
THINS...850 TEMPS BECOME COLDER...SO HELD ONTO SOME FLAKES EVEN
INTO TUESDAY EAST OF THE OHIO RIVER.
STILL DRY ON WEDNESDAY. WARMING 850 TEMPS WEDNESDAY NIGHT INTO
THURSDAY. NEXT WESTERN FRONT LONG ABOUT THURSDAY AFTERNOON.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
06Z FRIDAY THRU 06Z SATURDAY...
A LOW PRESSURE SYSTEM WILL APPROACH FROM THE SOUTH SOUTHWEST TODAY.
CIGS WILL LOWER AS PRECIP MOVES IN FROM THE SW THIS
AFTERNOON...FIRST ACROSS SW VA AND SE WV AFFECTING KBKW BY 18Z
WITH MVFR. PRECIPITATION OVERSPREADS THE REGION TOWARD EVENING
WITH MOST OF REMAINING TERMINALS EXPERIENCING MVFR CIGS IN PRECIP
BY 21Z. MVFR VSBY WILL LAG BEHIND A FEW HRS. EXPECT BULK OF PRECIP
THRU 00Z TO BE LIQUID...SAVE FOR A HR OR TWO OF A MIX FOR KBKW AT
ONSET.
CIGS WILL LOWER INTO IFR TONIGHT WITH A GRADUAL CHANGEOVER TO WET
SNOW. VSBY WILL FOLLOW SUITE WITH LOCALIZED VLIFR VSBY. IN THE
HIGH TERRAIN A VARIETY OF PRECIP TYPES CAN BE EXPECTED THIS
EVENING DEPENDING ON ELEVATION.
LOW LEVEL FLOW WILL BRIEFLY STRENGTHEN OUT OF SSE THIS
MORNING...PROVIDING FOR SOME 15 TO 20 KT GUSTS AT KBKW. OTHERWISE 5
TO 10 KT WINDS OUT OF NE FOR W TERMINALS AND E FOR THE MOUNTAIN
TERMINALS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SATURDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIO: TIMING LOWERING OF CIGS INTO MVFR OR WORSE
ALONG WITH VSBY MAY VARY A FEW HRS THIS AFTERNOON/EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE FRI 01/23/15
UTC 1HRLY 08 09 10 11 12 13 14 15 16 17 18 19
EST 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H M H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H M H H H H H H H H
PKB CONSISTENCY H H H M M H H H H H H H
CKB CONSISTENCY M M M H H H H H H H H H
AFTER 06Z SATURDAY...
IFR POSSIBLE EARLY SATURDAY MORNING IN SNOW. IFR POSSIBLE IN SNOW IN
THE HIGHER ELEVATIONS OF THE MOUNTAINS SUNDAY/SUNDAY NIGHT. IFR
POSSIBLE AREA WIDE IN SNOW SHOWERS MONDAY/MONDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 10 AM EST
SATURDAY FOR WVZ046-047.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...KTB
AVIATION...30
AREA FORECAST DISCUSSION
NWS TULSA OK
1118 PM CST THU JAN 22 2015
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. CEILINGS
IN THE 5-10 THOUSAND FEET RANGE WILL PREVAIL THROUGH TONIGHT
ACROSS SE OK AND WC AR.
&&
.PREV DISCUSSION... /ISSUED 806 PM CST THU JAN 22 2015/
UPDATE...
POPS HAVE BEEN REDUCED IN THE SOUTH FOR TONIGHT. SEE DISCUSSION BELOW...
DISCUSSION...
THE LATEST SHORT RANGE DATA...INCLUDING THE HRRR AND RAP...SUGGEST
PRECIP SHOULD REMAIN TO OUR SOUTH AND EAST TONIGHT. THE WARM
CONVEYOR PRECIP HAS SHIFTED EAST...AND THE MAIN UPPER SYSTEM IS
STILL OUT AROUND THE BIG BEND REGION AND IS NOT GAINING ANY
LATITUDE. HAVE THUS PULLED BACK ON PRECIP CHANCES TONIGHT. THE 18Z
GFS IS THE ONLY SOLUTION THAT HAS PRECIP NORTH OF THE RED
RIVER...SO I HAVE LEFT SLIGHT CHANCES OR LOW END CHANCE POPS IN
THE FAR SOUTHEAST.
LACY
PREV DISCUSSION... /ISSUED 516 PM CST THU JAN 22 2015/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. CEILINGS
IN THE 5-10 THOUSAND FEET RANGE WILL PREVAIL THROUGH TONIGHT
ACROSS SE OK AND WC AR.
PREV DISCUSSION... /ISSUED 300 PM CST THU JAN 22 2015/
DISCUSSION...
A LONGWAVE UPPER TROUGH WILL TRAVERSE THE SOUTHERN PLAINS OVERNIGHT
TONIGHT. RELATED PRECIPITATION IS EXPECTED TO REMAIN CONFINED TO FAR
SOUTHEAST OKLAHOMA AND WEST CENTRAL ARKANSAS. WITH TEMPERATURES
ACROSS THIS AREA FALLING FROM NEAR 40 THIS AFTERNOON TO THE LOW TO
MID 30S TONIGHT... SOME SNOWFALL WILL BE POSSIBLE... MAINLY AFTER
MIDNIGHT. LITTLE IF ANY ACCUMULATION IS EXPECTED. ALL PRECIPITATION
CHANCES WILL END BY MID MORNING FRIDAY AS THE UPPER TROUGH CONTINUES
EASTWARD.
ANOTHER SUSTAINED WARMING TREND WILL BEGIN SATURDAY... LASTING
THROUGH AT LEAST THURSDAY. DAILY MAX AND MIN TEMPERATURES WILL
EVENTUALLY RUN 10 TO 15 DEGREES ABOVE SEASONAL AVERAGES AS UPPER
RIDGING BUILDS ACROSS THE SOUTHERN PLAINS DURING THE UPCOMING WEEK.
FROM SUNDAY ON... AFTERNOON HIGHS IN THE 60S WILL BE COMMON ACROSS
THE FORECAST AREA... WITH SOME 70S POSSIBLE BY MID WEEK. OVERNIGHT
LOWS ARE EXPECTED TO REMAIN ABOVE FREEZING AREAWIDE... WHILE SLOWLY
INCREASING DURING THE MIDDLE OF THE WEEK. PRECIPITATION CHANCES WILL
BE MINIMAL THROUGHOUT THE NEXT 7 DAYS OR SO.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 25 49 31 57 / 0 0 0 0
FSM 35 48 29 54 / 10 10 0 0
MLC 33 48 29 56 / 10 10 0 0
BVO 25 49 27 56 / 0 0 0 0
FYV 30 45 26 51 / 0 0 0 0
BYV 29 45 28 50 / 0 0 0 0
MKO 31 47 30 55 / 0 0 0 0
MIO 27 47 29 52 / 0 0 0 0
F10 32 48 31 56 / 0 0 0 0
HHW 34 49 29 57 / 20 20 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...99
LONG TERM....99
AVIATION...14
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
100 AM EST FRI JAN 23 2015
.SYNOPSIS...
A DEVELOPING AREA OF LOW PRESSURE WILL TRACK ALONG THE GULF AND
SOUTH ATLANTIC COASTS THROUGH FRIDAY NIGHT...BEFORE MOVING UP THE
EAST COAST OVER THE WEEKEND. THE LOW WILL BRING WIDESPREAD
PRECIPITATION OVER OUR AREA FRIDAY INTO SATURDAY. HIGH PRESSURE WILL
BRIEFLY BUILD IN ON SUNDAY...BEFORE A COLDER LOW PRESSURE SYSTEM
AFFECTS THE FORECAST AREA SUNDAY NIGHT THROUGH TUESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 1255 AM...A BAND OF LIGHT PRECIP CONTINUES TO OOZE NORTH
ACROSS CENTRAL GEORGIA...AND WILL MAKE A RUN AT THE LOWER SC AND
NORTHEAST GEORGIA PIEDMONT OVER THE NEXT COUPLE OF HOURS. AT THIS
HOUR...SURFACE WET BULB TEMPS ARE WELL ABOVE FREEZING ACROSS THE
SOUTHERN HALF OF THE AREA...UPPER 30S TO LOWER 40S. THUS...ONLY RAIN
WITH PERHAPS A SLEET PELLET OR TWO MIXED IN IS EXPECTED ACROSS MUCH
OF THE UPSTATE AND NORTHEAST GEORGIA. P-TYPE SHOULD BECOME MORE
INTERESTING AS PRECIP MOVES INTO THE MOUNTAINS AND FAR NC NORTHERN
PIEDMONT/FOOTHILL AREAS LATER THIS MORNING...BUT THIS WON/T OCCUR
FOR SEVERAL MORE HOURS.
AS OF 945 PM EST...THE LEADING EDGE OF LIGHT PRECIPITATION FALLING
FROM MID LEVEL CLOUD BASES IS APPROACHING THE CWFA FROM THE SW LATE
THIS EVENING...AND THE ONSET OF POP HAS BEEN ACCELERATED FOR THE
NIGHTTIME HOURS. NO CHANGES WILL BE MADE TO THE ADVISORY AREA SINCE
THE LATEST RAP AND INCOMING 00Z NAM PROFILES LOOK VERY SIMILAR TO
THE PREVIOUS MODEL RUNS.
OTHERWISE...WATER VAPOR IMAGERY CONTINUES TO SHOW THE MAIN DRIVING
UPPER LOW MOVING INTO W TX LATE THIS EVENING...WITH SFC DEVELOPMENT
CONTINUING ALONG THE WRN GULF COAST AHEAD OF THIS FEATURE. DEEPER
LAYER MOISTURE AND RAPIDLY INCREASING ISENTROPIC LIFT WILL START
SPREADING INTO THE EXTREME SW SECTIONS 09Z TO 12Z...SPREADING
CATEGORICAL LIGHT TO MODERATE PRECIPITATION COVERAGE ACROSS THE
REGION THROUGH MIDDAY. MEANWHILE...1030 MB SFC HIGH PRES CONTINUES
TO LAY OVER TO THE N OF THE AREA...WITH CHILLY LOW LEVEL
THICKNESSES AND DRIER AIR PARKED ACROSS WRN NC. MODEL PROFILES FROM
ASHEVILLE TO W OF HICKORY TO NEAR BOONE SUPPORT SNOW AT ONSET
OVERNIGHT...WITH WET BULB PROFILES ISOTHERMAL NEAR ZERO. SOME DEGREE
OF WARM NOSING IS EXPECTED TO DEVELOP FRI MORNING...WITH A STEADY
TRANSITION TO SLEET THROUGH MID MORNING AND THEN BRIEF FREEZING RAIN
LINGERING ACROSS THE NRN BLUE RIDGE INTO THE AFTERNOON. PROFILES
SUPPORT MAINLY LIQUID ACROSS SC...NE GA...AND THE NC
PIEDMONT...ALTHOUGH BRIEF SLEET AT THE ONSET WILL BE POSSIBLE JUST
ABOUT ANYWHERE.
THE TRANSIENT NATURE OF THE WINTRY PTYPES ACROSS THE NC MTNS WILL
LIKELY WORK TO KEEP ANY ONE PTYPE FROM REACHING WARNING CRITERIA.
THE CURRENT ADVISORY SUITE REMAINS WELL PLACED...WITH LIGHT SNOW AND
ICE ACCUMULATIONS FRI...WITH A TRANSITION TO ADDITIONAL LIGHT NW
FLOW SNOW ACCUMULATIONS INTO FRI NIGHT. WILL KEEP TEMPS NEAR RAW
MODEL VALUES...WITH A BRIEFLY GUSTY NE FLOW POSSIBLE EAST OF THE
MTNS AS A BARRIER JET FORMS DESPITE THE WEAK DAMMING HIGH POSITION.
PRECIP RATES WILL LIKELY START TO SLACKEN FROM THE SW VERY LATE IN
THE DAY AS WEAK MID LEVEL DRYING BEGINS TO WORK BACK IN.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
AS OF 230 PM THURSDAY...THE SHORT TERM PICKS UP AT 00Z
SATURDAY...WITH MODELS IN GOOD AGREEMENT ON THE SFC LOW CENTERED
INVOF TALLAHASSEE FL...WITH A SHARP H5 TROF AXIS ACRS THE LWR MS
VALLEY. FRIDAY EVENING LOOKS LIKE A CONTINUED TRANSITION TO ALMOST
ALL RAIN ACRS THE CWFA...AS LLVL FLOW TURNS FROM SE TO SW...AND A
DRY SLOT PUNCHES INTO THE SRN APPALACHIANS FROM THE SW. TEMPS MAY BE
ABLE TO HOLD AROUND 30-32 ALONG THE ERN SLOPES OF THE NRN NC BLUE
RIDGE. HOWEVER...ADDITIONAL ICE ACCUMS SHUD BE VERY LIGHT...WITHIN A
LULL IN PRECIP. BY 12Z SAT...A DEFORMATION ZONE WITHIN THE MID LVL
TROF WILL ENTER THE NC MTNS...BRINGING FALLING MID LVL HEIGHTS (AND
SNOW LEVELS)...WHILE INCREASING THE POP. TAKING A BLEND OF THE
NAM/SREF WITH THE WPC QPF (THROWING OUT THE GFS)...I GET 1-2" OF
ADDITIONAL SNOW ACCUM MAINLY ABOVE 3500 FT SATURDAY MORNING. THE
DEFORMATION ZONE WILL TRANSLATE EAST QUICKLY...WITH POPS TAPERING
OFF BY MIDDAY. BY SATURDAY AFTN...NWLY 850 MB FLOW WILL
INCREASE...KEEPING A SLGT CHC TO LOW-END CHC OF SNOW SHWRS ALONG THE
TN/NC BORDER. GRADUAL CLEARING IS EXPECTED EAST OF THE MTNS. TEMPS
WILL HOVER IN THE 30S ACRS THE AREA FRIDAY NIGHT TO NEAR 40 IN THE
UPR SAVANNAH VALLEY...THEN WARM LITTLE ABOVE 3500 FT...BUT INTO THE
MID-UPR 40S ACRS THE PIEDMONT ON SATURDAY.
SATURDAY NIGHT AND SUNDAY...A BROAD H5 TROF WILL LINGER IN WAKE OF
THE SATURDAY TROF PASSAGE. THE CWFA WILL BE IN BETWEEN A NOREASTER
AFFECTING THE MID ATLANTIC/NEW ENGLAND...AND A CLIPPER THAT WILL BE
DIVING INTO THE WRN GREAT LAKES. ANOTHER VORT MAX WILL CROSS THE NC
MTNS SATURDAY NIGHT WITHIN THE LONGWAVE TROF. IT WILL HAVE LITTLE
MOISTURE TO WORK WITH...BUT THE NAM AND GFS BOTH SHOW A HUNDREDTH OR
TWO OF QPF RESPONSE ALONG THE TN/NC NWLY FLOW UPSLOPE AREAS. I
BUMPED UP POPS BACK TO CHC SATURDAY NIGHT FROM MADISON TO AVERY
COUNTY FOR SNOW SHWRS. LITTLE OR NO ACCUMS ARE EXPECTED. THE LLVL
FLOW WILL BACK TO W-SWLY ON SUNDAY...AND GUIDANCE IN GOOD AGREEMENT
ON A DRY DAY ACRS THE CWFA AHEAD OF THE APPROACHING CLIPPER SYSTEM.
TAKING A MODEL BLEND...I GET NEAR NORMAL TEMPS UNDER PARTLY CLOUDY
SKIES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 200 PM THU...LONGWAVE TROUGH PERSISTS OVER THE ERN CONUS THRU
THE MOST OF THE MEDIUM RANGE. THE UPPER PATTERN IS INITIALLY LOCKED
IN PLACE BY A REX BLOCK OVER THE WEST COAST...WHICH BREAKS DOWN
MONDAY. GLOBAL MODELS DIFFER IN HOW THE PATTERN SUBSEQUENTLY EVOLVES
OVER THE WEST BUT AGREE RIDGING WILL OCCUR OVER THE EAST BY WED
NIGHT. WHILE THE ERN TROUGH REMAINS IN PLACE...A SERIES OF CLIPPER-
LIKE SHORTWAVES WILL MOVE ACROSS OUR AREA. MEAN NWLY FLOW WILL
CONTINUE...SUGGESTING A CONTINUED FOCUS FOR PRECIP CHANCES ALONG THE
WRN FACING SLOPES OF THE NC MTNS. THE PASSING SHORTWAVES APPEAR
CAPABLE OF FORCING VERY LIGHT PRECIP OVER THE PIEDMONT...MAINLY THE
NC SIDE. DOWNSLOPING WILL BE WORKING AGAINST SAID FORCING AND ONLY
LOW POPS AND QPF WILL BE ADVERTISED THERE. IN THE MTNS...BLENDED QPF
FROM THE GLOBAL MODELS AND AN EXPECTATION OF PREDOMINANTLY SNOW AS A
PTYPE SUGGEST TOTALS GENERALLY 1-2 INCHES IN THE 12 HR PERIODS
SUNDAY NIGHT AND MONDAY. THIS MAY WARRANT A WINTER WX ADVY.
THE 22/12Z GFS CONTINUES TO EXHIBIT A COUPLE OF KEY DIFFERENCES FROM
THE CORRESPONDING GEM OR EC. THE FIRST IS IN THE WELL DEFINED
SHORTWAVE CROSSING THE AREA MONDAY...WHICH DOES NOT COME AS FAR SOUTH
ON THE GFS PROGS AND IS FOLLOWED BY A SECONDARY CHANNELED AREA OF
VORT. THE EC DEPICTS A MORE BROAD TROUGH WITH DISTINCT EDDIES DARTING
THROUGH WITHIN. THE EC BRINGS ANOTHER WAVE OF LIGHT QPF INTO THE AREA
TUESDAY AS A RESULT...WHEN TEMPS HAVE COOLED TO BECOME A LITTLE MORE
SUPPORTIVE OF WINTRY PRECIP. THE GEM LOOKS MORE LIKE THE EC THAN THE
GFS BUT DOES NOT RESPOND WITH QPF TUE. RUN-TO-RUN CONSISTENCY IS NOT
THAT GREAT FOR ANY OF THE MODELS WITH THE SMALLER SCALE WAVES AND
ASSOCIATED QPF. WITH THIS PACKAGE THE PIEDMONT POPS HAVE BEEN
EXPANDED SLIGHTLY THRU EARLY TUE ON ACCOUNT OF CONTINUED HINTS AT
PRECIP.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AT KCLT...MID-LEVEL CIGS WILL CONTINUE TO FILL IN AND GRADUALLY
LOWER...AS MOISTURE AND RISING MOTION INCREASE IN ADVANCE OF
DEVELOPING GULF COASTAL STORM SYSTEM. RAIN CHANCES WILL INCREASE BY
12Z. BY LATE MORNING...RAIN SHOULD BE ONGOING...WITH LOWERING CIGS
AND VISBY EXPECTED IN SATURATING LOW LEVEL AIR MASS. IFR CIGS AND AT
LEAST PERIODIC IFR VISBY CAN BE EXPECTED BY NOON...IF NOT A LITTLE
SOONER. ONCE CONDITIONS DETERIORATE...THEY WILL BE SLOW TO
RECOVER...AS A HYBRID COLD AIR DAMMING EVENT BECOMES ESTABLISHED
ACROSS THE REGION. RAIN IS EXPECTED TO BEGIN DIMINISHING BY THE END
OF THE PERIOD...BUT CIGS AND VISBY SHOULD REMAIN LOW IN PERSISTENT
COOL WEDGE. NE WINDS WILL PERSIST THROUGH THE PERIOD...GENERALLY
LIGHT EARLY THIS MORNING...BUT INCREASING TO 8-12 KTS BY AFTERNOON.
ELSEWHERE...CIGS AND PRECIP CHANCES WILL GRADUALLY INCREASE THROUGH
THE OVERNIGHT HOURS...WITH RAIN EXPECTED TO BEGIN IN EARNEST BY
AROUND SUNRISE AT MOST TERMINALS (A COUPLE OF HOURS LATER AT KHKY).
LOWERING CIGS AND VISBY ARE EXPECTED IN SATURATING LOW LEVEL AIR
MASS. IFR CIGS AND AT LEAST PERIODIC IFR VISBY CAN BE EXPECTED BY
LATE-MORNING AT MOST TERMINALS...IF NOT A LITTLE SOONER. ONCE
CONDITIONS DETERIORATE...THEY WILL BE SLOW TO RECOVER...AS A HYBRID
COLD AIR DAMMING EVENT BECOMES ESTABLISHED ACROSS THE REGION. RAIN
IS EXPECTED TO BEGIN DIMINISHING BY THE END OF THE PERIOD...BUT CIGS
AND VISBY SHOULD REMAIN LOW IN PERSISTENT COOL WEDGE. NE WINDS WILL
PERSIST THROUGH THE PERIOD (PRIMARILY SE AT KAVL)...GENERALLY LIGHT
EARLY THIS MORNING...BUT INCREASING TO 8-12 KTS BY AFTERNOON.
OUTLOOK...WHILE PRECIPITATION IS EXPECTED TO DIMINISH...
RESTRICTIONS SHOULD CONTINUE LATE FRIDAY NIGHT BEFORE DIMINISHING
FROM THE SW ON SAT. A SERIES OF CLIPPER SYSTEMS WILL BRING SNOW
CHANCES TO THE AREA EARLY IN THE WEEK...MAINLY TO THE MTNS NORTH AND
WEST OF KAVL.
CONFIDENCE TABLE...
06-12Z 12-18Z 18-24Z 00-06Z
KCLT HIGH 100% MED 63% MED 77% HIGH 81%
KGSP HIGH 100% HIGH 85% HIGH 85% HIGH 83%
KAVL HIGH 100% MED 71% HIGH 85% HIGH 83%
KHKY HIGH 100% MED 67% HIGH 81% MED 73%
KGMU HIGH 100% HIGH 85% HIGH 92% HIGH 83%
KAND HIGH 100% MED 75% MED 74% HIGH 83%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WINTER WEATHER ADVISORY FROM 6 AM THIS MORNING TO NOON EST
SATURDAY FOR NCZ033-048>052-058-059-062>064-501-503-505.
SC...NONE.
&&
$$
SYNOPSIS...WIMBERLEY
NEAR TERM...HG/JDL
SHORT TERM...ARK
LONG TERM...WIMBERLEY
AVIATION...JDL
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1129 PM CST THU JAN 22 2015
.UPDATE...
06Z AVIATION UPDATE.
&&
.AVIATION...
CEILINGS ARE SLOWLY FALLING THIS EVENING...AND WILL CONTINUE TO DO
SO AS PRECIP WORKS ITS WAY INTO THE REGION FROM THE SOUTH. MVFR
CEILINGS SHOULD IMPACT KBNA AND KCSV FIRST AROUND 9Z TO 11Z...THEN
KCKV BY 11Z AS RAIN CHANCES MOVE IN. THERE IS A CHANCE FOR SOME
SLEET DURING THE EARLY ONSET OF RAIN CHANCES BEFORE 12Z AS WELL. SOME
GUIDANCE SUGGESTS THAT EVEN IFR CEILINGS WILL MOVE INTO ALL
TERMINALS BY LATE MORNING AS THE RAIN IS OVER MIDDLE TN...AND EVEN
LIFR AT KCSV BY LATE MORNING. KEPT KBNA AT LOW MVFR TOMORROW WITH
KCKV AT IFR AND KCSV NEAR LIFR FOR THE AFTERNOON. IT LOOKS LIKE
CEILINGS MAY COME UP A BIT DURING THE EVENING AS PRECIP MOVES OUT
OF THE REGION FROM WEST TO EAST...BUT SHOULD REMAIN BELOW VFR
UNTIL OVERNIGHT AND INTO SATURDAY.
&&
.PREV DISCUSSION... /ISSUED 843 PM CST THU JAN 22 2015/
UPDATE...
LATEST SURFACE OBSERVATIONS SHOW TEMPERATURES IN THE UPPER 30S TO
AROUND 40 ACROSS THE FORECAST AREA WITH DEWPOINTS IN THE MID 20S
TO LOWER 30S. THESE TEMPS ARE ALREADY AT FORECAST LOWS ACROSS THE
SOUTH...AND HAVE GONE AHEAD AND LOWERED MINS FOR TONIGHT AREAWIDE
CLOSER TO OUR SUPERMODEL BLEND. RADAR IMAGERY SHOWS LIGHT TO
MODERATE RAIN CONTINUES JUST TO OUR SOUTH ACROSS NORTHERN
MS/AL...AND THERE HAVE BEEN SEVERAL REPORTS OF SLEET MIXING IN
WITH THE RAIN AT TIMES WHERE PRECIP HAS BEEN HEAVIER. BASED ON
THESE REPORTS ALONG WITH HRRR AND A LOOK AT LATEST FORECAST
SOUNDINGS...WILL ADD A CHANCE OF SLEET TO ZONES FOR TONIGHT AS
DRY AIR IN THE LOWER TROPOSPHERE MAY ALLOW FOR BRIEF PERIODS OF
SLEET...ESPECIALLY ACROSS THE COOLER NORTHERN ZONES. NO SLEET
ACCUM IS EXPECTED DUE TO ABOVE FREEZING TEMPS. THERMO PROFILES IN
THE NORTHWEST MID STATE ARE VERY CLOSE TO BEING A RAIN/SNOW MIX
FOR A BRIEF TIME FRIDAY MORNING PER 00Z NAM...BUT EXPECTED LIGHT
NATURE OF PRECIP SHOULD KEEP EVERYTHING RAIN/POSSIBLE SLEET.
REST OF FORECAST FOR THE FRIDAY/FRIDAY NIGHT PERIOD REMAINS
GENERALLY ON TRACK...WITH RAIN CONTINUING AREAWIDE INTO THE
AFTERNOON BEFORE A BRIEF LULL IN PRECIPITATION. MORE RAIN THEN
MOVES IN FRIDAY EVENING AS UPPER TROUGH AXIS MOVES ACROSS...WITH
CAA ALOFT ALLOWING FOR THE RAIN TO MIX WITH AND EVENTUALLY
CHANGEOVER TO SNOW FRIDAY NIGHT BEFORE ENDING SATURDAY MORNING. A
LOOK AT LATEST COBB SNOW TOTALS FOR THE NAM AND GFS CONTINUE TO
SUGGEST A DUSTING TO HALF INCH OF SNOW POSSIBLE FOR MUCH OF THE
MID STATE FRIDAY NIGHT...WITH HIGHEST AMOUNTS IN THE HIGHER
ELEVATIONS OF THE HIGHLAND RIM AND ON THE CUMBERLAND PLATEAU. ANY
SNOW WOULD MAINLY ACCUMULATE ON GRASSY AREAS AND ELEVATED SURFACES
DUE TO THE LOW SNOW RATIOS EXPECTED AND TEMPERATURES REMAINING
NEAR/ABOVE FREEZING...SO NO SIGNIFICANT IMPACTS TO TRAVEL ARE
ANTICIPATED WITH THIS EVENT. ANY SNOW THAT CAN ACCUMULATE WILL
MELT QUICKLY SATURDAY MORNING AS TEMPERATURES WARM WELL INTO THE
40S.
SHAMBURGER
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
06
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1020 PM CST THU JAN 22 2015
.DISCUSSION...SEE AVIATION DISCUSSION FOR 06Z TAFS. ALSO ADJUSTED
POPS FOR INCREASED ACTIVITY AND GOING AREAL COVERAGE RATHER THAN
CHANCE/SLIGHT CHANCE.
&&
.AVIATION...MVFR CONDITIONS WILL CONTINUE OVERNIGHT ALONG WITH AREAS
OF LIGHT RAIN. HAVE A TEMPO GROUP IN EACH TAF TO ADDRESS SLIGHTLY
HEAVIER RAINFALL LATER TONIGHT INTO EARLY FRI MORNING IN RESPONSE TO
THE UPPER LOW SWINGING ACROSS THE REGION. CONDITIONS WILL IMPROVE TO
VFR LEVELS THROUGH MID MORNING ON FRI FROM WEST TO EAST. MOD NLY
WINDS WITH GUSTS TO AROUND 25KT TONIGHT WILL CONTINUE INTO FRI
MORNING THEN WILL SUBSIDE BY FRI AFTERNOON. SHOULD SEE LIGHT
MAINLY NORTHERLY WINDS AFTER 24/00Z.
&&
.PREV DISCUSSION... /ISSUED 842 PM CST THU JAN 22 2015/
DISCUSSION...AREAS OF LIGHT TO MODERATE RAINFALL HAVE DEVELOPED
IN THE PAST HOUR NEAR THE SOUTHERN COASTAL COUNTIES. HRRR 4 KM HAS
BEEN FLUCTUATING A BIT WITH RAIN OVER THE AREA FROM THE LAST
COUPLE OF RUNS. LATEST RUN IS SHOWING SOME RAIN CONTINUING INTO
THE OVERNIGHT HOURS. THUS...AM GOING TO KEEP THE CHANCE POPS GOING
FOR TONIGHT. HOWEVER...AM GOING TO LOWER THEM JUST A TAD OVER THE
VICTORIA AREA TO 40 POPS. OTHERWISE...GFE FORECAST MONITOR IS
SHOWING TEMPERATURES AND DEW POINTS MUCH IN LINE WITH CURRENT
FORECAST (GREEN). AS A RESULT...WILL KEEP ON-GOING FORECAST GOING
CONCERNING TEMPS/WINDS/DEW POINTS SINCE FORECAST OVERALL IS IN
REALLY GOOD SHAPE.
MARINE...SCA SEEMS TO BE WORKING FINE. WILL LOWER POPS JUST A BIT
OVER THE GULF WATERS...AS EXPECT AREAS OF RAIN TO MAINLY STAY
INLAND. STILL CHANCE POPS FOR THE NEARSHORE AND BAYS. SEAS ALREADY
NEAR 10 FEET AT BOY019...AS IT SHOWS IN FORECAST. THUS...NO
OTHER CHANGES NEEDED AT THIS TIME BESIDES THE SLIGHT POP ADJUSTMENT.
PREV DISCUSSION... /ISSUED 521 PM CST THU JAN 22 2015/
DISCUSSION...SEE AVIATION DISCUSSION BELOW FOR THE 00Z TAFS.
AVIATION...MVFR CONDITIONS ARE EXPECTED TO PREVAIL OVERNIGHT
ALONG WITH ADDITIONAL -RA AS AN UPPER LEVEL LOW SWINGS ACROSS TX.
CONDITIONS ARE FCST TO IMPROVE AROUND MID MORNING FRI AS THE UPPER
LOW EXITS THE REGION AND DRIER AIR BEGINS TO FILTER INTO S TX. LRD
IS EXPECTED TO IMPROVE TO VFR INITIALLY THEN IMPROVING CONDITIONS
WILL SPREAD EAST THROUGH THE DAY.
PREV DISCUSSION... /ISSUED 253 PM CST THU JAN 22 2015/
SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...COLD FRONT HAS
PUSHED OFF THE MIDDLE TEXAS COAST WITH A COLD AIRMASS ALREADY
SETTLED INTO THE REGION WITH COLD AIR ADVECTION CONTINUING THROUGH
THE NIGHT AS BREEZY/WINDY NORTHERLY WINDS PERSIST. AREAS OF LIGHT
RAIN CONTINUE TO DRIFT ACROSS INLAND AREAS AS OF MID AFTERNOON BUT
SHOULD GRADUALLY DISSIPATE EARLY THIS EVENING. ADDITIONAL RAIN
/MAINLY LIGHT/ IS PROG TO DEVELOP OVERNIGHT AS MUCH OF THE CWA
BECOMES PLACED IN THE RRQ OF A 110KT H25 JET STREAK AND A MID
LEVEL TROUGH AXIS APPROACHES THE REGION. RAIN CHANCES WILL
DECREASE EARLY FRIDAY AS MID LEVEL TROUGH BEGINS TO SHIFT EAST AND
LLVL MOISTURE DECREASES. GRADUAL CLEARING MAY OCCUR FROM NW TO SE
TOMORROW AFTERNOON...BUT OVERALL AM EXPECTING A MOSTLY CLOUDY DAY.
CONTINUED COLD AIR ADVECTION AND CLOUD COVER WILL KEEP DAYTIME
TEMPS WELL BELOW NORMAL WITH SOME LOCATIONS ACROSS NE ZONES
STRUGGLING TO GET OUT OF THE 40S. SURFACE RIDGE AXIS EXTENDS INTO
S TX FRIDAY NIGHT RESULTING IN DRY LOW LEVEL AIRMASS AND LIGHT
WINDS...ALLOWING FOR STRONG RADIATIONAL COOLING WITH TEMPS
AREAWIDE LIKELY TO FALL INTO THE 30S.
LONG TERM...(SATURDAY THROUGH THURSDAY)...TROUGH AXIS WILL BE EAST
OF THE AREA ON SATURDAY...WITH DRIER AIR FILTERING INTO SOUTH TEXAS.
WINDS WILL ALSO BE RELAXING AS PRESSURE GRADIENT WEAKENS. COOLEST
DAY OF THE EXTENDED WILL SATURDAY BEHIND DEPARTING TROUGH. HIGHS
WILL ONLY BE IN THE LOWER/MIDDLE 60S. WARMING TREND WILL THEN
COMMENCE ON SUNDAY. UPPER LEVEL RIDGE WILL REMAIN THE MAIN WEATHER
FEATURE ACROSS SOUTH TEXAS FOR THE UPCOMING WEEK. THIS WILL LEAD TO
QUIET WEATHER OVER THE AREA AND TEMPERATURES ABOVE NORMAL FOR THE
END OF JANUARY. HIGHS WILL GENERALLY BE IN THE LOWER TO MIDDLE 70S
OVER INLAND LOCATIONS...WITH MID/UPPER 60S ALONG THE IMMEDIATE
COAST.
MARINE...AS OF MID AFTERNOON A COLD FRONT WAS MOVING EAST ACROSS
THE OFFSHORE WATERS WITH A STRONG OFFSHORE FLOW AND HAZARDOUS
SEAS DEVELOPING IN ITS WAKE. SMALL CRAFT ADVISORIES ARE IN EFFECT
FOR ALL MARINE AREAS TONIGHT INTO FRIDAY. CONDITIONS WILL
GRADUALLY IMPROVE FRIDAY NIGHT WITH PLEASANT MARINE CONDITIONS
CURRENTLY EXPECTED OVER THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 45 52 34 64 43 / 30 20 10 0 10
VICTORIA 43 50 34 62 39 / 30 30 10 0 10
LAREDO 43 55 37 65 42 / 30 10 0 0 0
ALICE 44 53 35 65 41 / 30 20 0 0 10
ROCKPORT 45 53 39 62 45 / 30 20 10 0 10
COTULLA 42 56 34 64 41 / 40 20 0 0 0
KINGSVILLE 45 54 35 66 42 / 30 20 0 0 10
NAVY CORPUS 46 52 38 62 47 / 30 20 10 0 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST FRIDAY NIGHT FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT
ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY
TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS
TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL NOON CST FRIDAY FOR THE FOLLOWING
ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT ARANSAS...
BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT O`CONNOR.
&&
$$
TE/81...AVIATION
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
340 AM CST FRI JAN 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST FRI JAN 23 2015
THE MAIN FOCUS FOR THE EARLY PART OF THE FORECAST IS ON THE
POTENTIAL FOR FREEZING RAIN AND SLEET THIS MORNING.
CURRENTLY...A NORTHEAST TO SOUTHWEST ORIENTED MID LEVEL SHORT WAVE
TROUGH IS DROPPING SOUTH INTO NORTHERN MINNESOTA WITH A BAND OF
LIGHT PRECIPITATION OUT AHEAD OF IT. AT THE SURFACE/LOW LEVELS...A
NORTH TO SOUTH ORIENTED WARM FRONT IS ADVANCING SOUTHEASTWARD AS
WELL ACROSS MINNESOTA WITH THIS WARM LAYER CAUSING SOME
PRECIPITATION TYPE ISSUES IN NORTHERN MINNESOTA. EVEN THOUGH
SURFACE TEMPERATURES HAVE CLIMBED ABOVE FREEZING...ROAD
TEMPERATURES ARE STILL BELOW FREEZING AND IS CAUSING SOME ICY
CONDITIONS. SIMILAR CONDITIONS ARE NOTED LOCALLY WITH ROAD SENSORS
SAYING ROAD TEMPERATURES ARE CURRENTLY IN THE UPPER 20S TO AROUND
30.
THE QUESTION LOCALLY IS WITH HOW MUCH OF THIS PRECIPITATION WILL
MAKE IT DOWN HERE AND HOW FAR SOUTHEAST WILL THE WARM LAYER MAKE
IT. 23.07Z RAP SOUNDINGS SHOW A SUBSTANTIAL DRY LAYER IN THE
LOWEST 5-6KFT OF THE PROFILE IN MOST SITES FROM POINTS SOUTH OF
SOUTHEAST MINNESOTA GOING EAST THROUGH CENTRAL WISCONSIN. FURTHER
NORTH...HOWEVER...TOWARD NORTH CENTRAL WISCONSIN THE POTENTIAL IS
THERE FOR DEEPER SATURATION AND A HIGHER CHANCE FOR PRECIPITATION.
THE WARM LAYER APPEARS TO CREEP UP TOWARD 1 TO 3C ABOVE
FREEZING...SO THERE WILL LIKELY BE SOME MELTING OF ANY ICE/SNOW
THAT TRIES TO FALL THROUGH THE COLUMN. THE WARMER PART OF THE WARM
NOSE APPEARS TO DROP DOWN FROM FAR NORTHWEST WISCONSIN DOWN TO
SOUTHEAST MINNESOTA/NORTH CENTRAL IOWA THIS MORNING...SO THE MAIN
PRECIPITATION TYPE THERE WOULD BE RAIN...IF IT PRECIPITATES. SAY
THAT IT DOES OCCUR...THE QUESTION BECOMES WHAT ROAD TEMPERATURES
WILL DO THROUGH THE MORNING.
OVERALL CONFIDENCE IS HIGHEST IN TAYLOR COUNTY THAT SOME ISSUES
WILL OCCUR WITH FREEZING RAIN/SLEET...SO WILL ADD THEM TO THE
ADVISORY. SHOULD THE PRECIPITATION MAKE IT FURTHER SOUTH...THEN A
SOUTHWARD EXPANSION TO THE ADVISORY MAY BE NEEDED...BUT CONFIDENCE
IS NOT HIGH ENOUGH AT THIS POINT TO DO THAT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 340 AM CST FRI JAN 23 2015
THE MAIN FOCUS IN THE EXTENDED PERIOD IS WITH THE SNOW AMOUNTS ON
SATURDAY NIGHT INTO SUNDAY AS A LOW PRESSURE SYSTEM DROPS DOWN
FROM SOUTHERN CANADA. CONFIDENCE IS HIGH THAT THIS SYSTEM WILL BE
MOVING THROUGH IN THE SATURDAY NIGHT/SUNDAY TIME FRAME...BUT
CONFIDENCE IS RATHER LOW WITH THE TRACK OF THE SYSTEM. THE 23.00Z
ECMWF IS THE FURTHEST SOUTH WITH THE LEAST AMOUNT OF SNOW...THE
23.00Z NAM IS THE SLOWEST AND HAS THE NARROWEST BAND MOVING
THROUGH WEST CENTRAL WISCONSIN AND THE 23.00Z GFS IS SOMEWHERE IN
BETWEEN THESE TWO WITH THE MOST WIDESPREAD AND HEAVIEST SNOW. AT
THIS POINT...CAN ONLY TAKE THE MIDDLE OF THE ROAD WHICH ENDS UP
BEING CLOSE TO THE GFS PATH WITH LESS QPF. STILL...WITH SNOW
RATIOS OF AROUND 13:1 AND QPF OF AROUND A QUARTER OF AN
INCH...COULD SEE SOME 2 TO 4 INCH SNOWS FROM THIS QUICK MOVING
SYSTEM. INCREASED THE PRECIPITATION CHANCES FOR THE EVENT SINCE
IT IS LOOKING LIKE MOST OF THE REGION WILL SEE SOME SNOW...IT IS
JUST A MATTER OF HOW MUCH.
BEYOND THIS...ONLY MADE SOME ADJUSTMENTS TO THE WEDNESDAY HIGH
TEMPERATURE FORECAST FOR WHAT APPEARS TO BE A STRONG SOUTHERLY
FLOW DAY WITH A WARM AIR MASS MOVING IN FROM THE SOUTH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1118 PM CST THU JAN 22 2015
BREEZY SOUTH TO SOUTHWEST WINDS ARE HELPING TO PUSH THE
PERSISTENT IFR/MVFR STRATUS DECK OFF TO THE EAST. RST SHOULD CLEAR
WITHIN THE NEXT 1-2 HRS WITH LSE IN 3-4 HRS. VFR CONDITIONS SHOULD
THEN PREVAIL UNTIL LATE AFTERNOON WHEN A COLD FRONT ARRIVES. ANY
PRECIPITATION ASSOCIATED WITH THIS FRONT SHOULD STAY TO THE NORTH.
HOWEVER...PLAN ON ANOTHER LOW STRATUS DECK TO MOVE IN BEHIND THE
FRONT. CEILINGS SHOULD START OFF MVFR...THEN FALL TO IFR AT RST
DURING THE EVENING...AIDED BY COOLING TEMPERATURES. THIS STRATUS
DECK WILL LIKELY REMAIN IN PLACE THROUGH SATURDAY.
REGARDING THE WINDS...A TIGHT PRESSURE GRADIENT IN PLACE WILL KEEP
A 10-20 KT BREEZE GOING UNTIL THE COLD FRONT ARRIVES. GUSTS OF
20-30 KT ARE ALSO POSSIBLE EARLY THIS MORNING AT RST WITH A
STRONGER WIND CORE COMING THROUGH ALOFT. EXPECT THE WINDS TO SWING
AROUND TO THE WEST AND EVENTUALLY NORTHWEST WITH THE PASSAGE OF
THE COLD FRONT. SPEEDS SHOULD DIMINISH SLIGHTLY LATE IN THE
EVENING WITH LOSS OF DAYTIME HEATING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ017.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1000 AM CST Fri Jan 23 2015
.UPDATE...
ISSUED AT 959 AM CST FRI JAN 23 2015
Have updated the forecast to slow the clearing trends and lower
the highs as a result. Clearing line is now just crossing the
Illinois/Iowa border. The latest RAP 925 mb humidity, which
appears to match the clouds fairly well, holds off on any
significant clearing in the northwest CWA until around mid
afternoon and not in the eastern CWA until after sunset. Have gone
with highs in the upper 30s over nearly all the forecast area,
except around 40 in west central Illinois where there is likely to
be some sunshine by mid to late afternoon.
&&
.SHORT TERM...(Today)
ISSUED AT 443 AM CST FRI JAN 23 2015
08z/2am IR satellite imagery shows low clouds blanketing central
Illinois, as moisture remains trapped beneath a subsidence inversion
centered around 900mb. With only very light low-level flow under
prevailing surface high pressure, am not expecting the clouds to
clear out anytime soon. HRRR suggests clouds will remain in place
through the morning, then will slowly begin to clear from west to
east during the afternoon. Based on satellite timing tools, think
clearing will be slightly faster, reaching the Illinois River Valley
by mid to late morning and the I-55 corridor by early afternoon.
The far E/NE KILX CWA around Champaign and Danville will likely
remain overcast through the entire day. High temperatures will
range from the upper 30s across the east where clouds will persist
longest to the lower 40s along/west of I-55 where sunshine will
prevail this afternoon.
&&
.LONG TERM...(Tonight through Thursday)
ISSUED AT 443 AM CST FRI JAN 23 2015
Weak short-wave trough currently evident on water vapor imagery over
southern Manitoba will drop into the Great Lakes tonight. Any light
precip associated with this feature will remain well north of
central Illinois: however, a weak frontal boundary will push through
the area, allowing winds to switch to northwesterly by morning.
Mild and dry conditions will be on tap behind the departing system
for Saturday with high temperatures topping out in the lower to
middle 40s.
Next more significant short-wave is still on target for Sunday, with
good model agreement concerning the strength and track of this
system. Surface low pressure will drop out of Canada on Saturday,
then will track from northeast Iowa Sunday morning to Ohio by Sunday
evening. With this particular track, the heaviest precipitation is
expected to remain further north along/north of the I-80 corridor.
Further south, the precip will be lighter and more scattered in
nature. Based on GFS/ECMWF timing, will introduce low chance PoPs
after midnight Saturday, with higher PoPs across the board during
the day Sunday. Atmospheric profile will remain marginal for snow,
so have only included a rain/snow mix along/north of I-74 Sunday
morning, before precip transitions to all rain by midday. May see a
change to light snow/flurries Sunday night as precip departs and
colder air returns, but no snow accumulation is expected.
After that, another wave will track well north of the area Monday
and Monday night: however, dry conditions are anticipated this far
south. Will be slightly cooler early next week as upper trough
remains in place across the eastern CONUS, resulting in highs in the
30s both Monday and Tuesday. The trough will shift eastward later
in the period, allowing temps to return to the 40s by Wednesday and
Thursday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 500 AM CST FRI JAN 23 2015
Back edge of MVFR cigs making slow progress into extreme eastern
Iowa this morning and should push into our western TAF areas
between 16 and 18z. Based on the latest movement, it appears
the clouds won`t push east of CMI until after 22z. Forecast
soundings suggest that once the skies clear, we can expect VFR
conditions thru at least the first half of tonight before a
weak frontal boundary tracks thru the region switching our
flow from southwest to northwest and ushering in another batch
of MVFR cigs for Saturday. Surface flow today will increase out
of the southwest at 10 to 15 kts and then diminish some from the
southwest early this evening before switching into the west and
northwest later tonight with speeds of 10 kts or less.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
531 AM CST FRI JAN 23 2015
.SHORT TERM...
302 AM CST
THROUGH SATURDAY...
EARLY MORNING WATER VAPOR IMAGERY SHOWS A CLOSED UPPER LOW
SPINNING OVER TEXAS AS PART OF A LARGER SCALE TROUGH THAT IS CUT
OFF FROM THE MAIN STREAM OF FLOW TO THE NORTH. THIS MAIN STREAM IS
POSITIONED ACROSS SOUTHERN CANADA WITH WITH SEVERAL EMBEDDED WAVES
TRACKING ACROSS MANITOBA AND SASKATCHEWAN TOWARD THE UPPER MIDWEST
AND UPPER GREAT LAKES. FURTHER WEST...LOW AMPLITUDE RIDGING IS
POSITIONED OVER THE WEST COAST WITH A WELL- DEFINED TROUGH MOVING
EASTWARD TOWARDS BRITISH COLUMBIA. AT THE SURFACE...HIGH PRESSURE
IS STRETCHED FROM THE SOUTHERN PLAINS TO NEW ENGLAND WITH A
SURFACE LOW OFF THE LOUISIANA COAST IN CONJUNCTION WITH THE TEXAS
UPPER LOW. ANOTHER SURFACE LOW IS OVER NORTHERN ONTARIO IN
CONJUNCTION WITH ONE OF THE WAVES OVER CENTRAL CANADA WITH A
TROUGH AXIS EXTENDING SOUTHWARD ACROSS THE NORTHERN PLAINS.
ABUNDANT BUT THIN CLOUD COVER REMAINS ACROSS THE REGION WITH
SATELLITE SHOWING VERY SLOW EASTWARD MOVEMENT...WITH THE BACK EDGE
STILL ACROSS EASTERN IOWA.
THE CLOUD COVER WILL BE THE MAIN CHALLENGE TODAY. FORECAST SOUNDINGS
SHOW A MIX OF THOUGHTS ON HOW LONG CLOUD COVER WILL HANG ON AND DO
NOT SEE MUCH IMPROVEMENT THROUGH LATE MORNING...THOUGH WESTERN AREAS
HAVE THE BEST CHANCE FOR SCATTERING BY MIDDAY. THE PRESSURE GRADIENT
WILL BEGIN TO TIGHTEN UP AS THE ONTARIO SURFACE LOW MOVES EAST AND
THE ASSOCIATED TROUGH APPROACHES. THIS WILL ALLOW FOR STEADIER
SOUTHWEST WINDS TO DEVELOP. WITH THE IDEA THAT CLOUDS WILL HANG ON
THROUGH THE MORNING THEN SCATTER THIS AFTERNOON...HIGH TEMPS WILL
PROBABLY STRUGGLE DESPITE THE SOUTHWEST WINDS AND MODEST WARM
ADVECTION ALOFT. WILL CONTINUE WITH MID AND UPPER 30S FOR NOW BUT IF
SUN CAN MAKE AN APPEARANCE FOR SEVERAL HOURS THIS AFTERNOON THEN
HIGHS AROUND 40/LOW 40S WOULD BE PLAUSIBLE. A BAND OF MID CLOUDS
WILL ACCOMPANY THE TROUGH PASSAGE EARLY THIS EVENING WITH A FEW
FLURRIES NOT OUT OF THE QUESTION. WINDS TURN NORTHWEST TONIGHT AND
SATURDAY MORNING WITH COOL ADVECTION OCCURRING. CLOUD COVER LOOKS
ABUNDANT SO HIGHS WILL LIKELY BE HELD IN THE MID/UPPER 30S.
MDB
&&
.LONG TERM...
302 AM CST
SATURDAY NIGHT THROUGH MONDAY...ATTENTION TURNS TO THE UPPER TROUGH
OFF THE BRITISH COLUMBIA COAST THIS MORNING. A SHORTWAVE EJECTS FROM
THIS TROUGH AND TRACKS EAST THEN SOUTHEAST AND ACROSS THE LOCAL AREA
EARLY SUNDAY. SURFACE LOW PRESSURE DEVELOPS AND PASSES WITH THE
UPPER TROUGH DURING THE DAY SUNDAY. GUIDANCE CONTINUES TO DISAGREE
ON THE STRENGTH AND TRACK OF THE SYSTEM WITH RECENT RUNS SHOWING
QUITE A BIT OF VARIATION. THESE NORTHWEST SYSTEMS HAVE HAD A
TENDENCY TO TRACK FURTHER SOUTH OR SOUTH AND WEST THAN DEPICTED
AHEAD OF TIME SO WILL NEED TO KEEP A CLOSE EYE ON THE WAVE AS IT
MOVES ONSHORE OVER BRITISH COLUMBIA LATER TONIGHT. AT THIS POINT...A
LOW TRACK ACROSS NORTHWEST OR WEST-CENTRAL ILLINOIS...SIMILAR TO THE
00Z GFS/ECMWF...LOOKS TO BE FAVORED WHEN CONSIDERING THE CURRENT AND
EXPECTED UPPER FLOW PATTERN. WITH WESTERN RIDGING EXPECTED TO
SHARPEN AS MORE PACIFIC ENERGY PUSHES INTO IT FROM THE WEST...THE
FLOW OVER THE ROCKIES/PLAINS WILL TURN MORE NORTHWESTERLY. ONE COULD
MAKE THE CASE THAT IF THE WAVE WERE TO TRACK THROUGH THE CURRENT
UPPER FLOW PATTERN IT WOULD TAKE A TRACK ACROSS THE AREA SO A MORE
NORTHWESTERLY FLOW WOULD SUPPORT A MORE WESTERN TRACK. A TRACK
FURTHER NORTH/EAST SEEMS UNLIKELY BUT WOULD NOT BE SURPRISED TO SEE
IT TRACK WEST OF THE TRACK OF THE 00Z GFS/ECMWF BASED ON THE
ABOVE. GIVEN THE PACIFIC ORIGINS OF THE SYSTEM THERE WILL BE
MOISTURE TO WORK WITH SO PRECIPITATION IS LIKELY WITH IT AND SHOULD
AFFECT MOST OF THE AREA UNLESS A WILD SWING IN THE TRACK OCCURS.
PRECIP TYPE MAY BE MIXED FOR A TIME AT ONSET...MAINLY SOUTH AND WEST
WITH A MORE SOUTH/WEST TRACK LEADING TO MAINLY SNOW FOR MUCH OF THE
AREA. THE 00Z RUN OF THE GFS/ECMWF SUGGEST A MIX EARLY SOUTH AS A
NOSE OF WARM AIR BRIEFLY BUILDS IN BEFORE COLD AIR FILLS IN AGAIN.
BASED ON PRECIPITABLE WATER VALUES AND DURATION OF FORCING THE HEART
OF THE SYSTEM LOOKS TO BE ABLE TO PRODUCE 0.3 TO PERHAPS 0.4 INCHES
OF LIQUID EQUIVALENT PRECIP WITH IT BECOMING A MATTER OF WHERE THE
HEART OF THE SYSTEM TRACKS.
ANOTHER ISSUE WILL BE THE POTENTIAL FOR LAKE ENHANCEMENT AS THE LOW
PASSES SUNDAY AFTERNOON/EVENING. A LOW TRACK TO THE SOUTH AND WEST
OF THE AREA WOULD BE SUPPORTIVE OF LAKE ENHANCEMENT OF SYNOPTIC
PRECIP ON THE BACK SIDE WITH THE COLUMN COLD ENOUGH TO SUPPORT SNOW
IN THIS SCENARIO. HIGH PRESSURE MOVES SOUTHWARD ACROSS ONTARIO INTO
MONDAY WITH ANOTHER SURFACE LOW/ELONGATED TROUGH STRETCHING FROM
MANITOBA TO THE CENTRAL PLAINS WHICH WILL TURN WINDS MORE EASTERLY
THEN SOUTHERLY INTO MONDAY EVENING. WITH FORECAST SOUNDINGS SHOWING
MARGINAL INVERSION HEIGHTS BUT SUFFICIENT DELTA T`S...MAY SEE A
SITUATION SIMILAR TO LAST WEEK WHERE LAKE EFFECT SNOW SHOWERS
PERSISTED IN THE EASTERLY LOW LEVEL FLOW BEFORE ENDING. THIS COULD
BE THE CASE FOR MUCH OF MONDAY. AS FAR AS TEMPS...HIGHS SUNDAY WILL
BE DICTATED BY THE LOW TRACK AND MONDAY LOOKS TO ONLY SEE HIGHS IN
THE 20S THANKS TO COLD ADVECTION.
TUESDAY THROUGH THURSDAY...BROAD RIDGING WEST AND TROUGHING EAST
WILL LEAVE THE LOCAL AREA UNDER A SHARP NORTHERLY UPPER FLOW
TUESDAY WITH HIGH PRESSURE AT THE SURFACE. THE RIDGING WILL
QUICKLY SHIFT EAST AND DE-AMPLIFY WEDNESDAY ALLOWING MILDER AIR TO
RETURN. THE FLOW MAY BE SOMEWHAT ACTIVE BUT PRECIP DETAILS ARE NOT
CLEAR AT THIS RANGE...THOUGH HAVE DECENT CONFIDENCE IN FAIRLY MILD
TEMPERATURES.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* MVFR CEILINGS AROUND 1500 FT INTO EARLY AFTERNOON.
* WEST-SOUTHWEST WINDS 220-250 DEG 12-15 KT WITH A FEW HIGHER
GUSTS.
RATZER
//DISCUSSION...UPDATED 12Z...
AREA OF MVFR CEILINGS AROUND 1500 FT EXTENDS WEST ACROSS THE
MISSISSIPPI INTO EASTERN IOWA. BACK EDGE MAKING SLOW PROGRESS TO
THE EAST...THOUGH EXPECT SOME EROSION AND ACCELERATION OF THIS
DURING THE DAY WITH MVFR CEILINGS DISSIPATING OR MOVING EAST OF
THE TERMINALS BY EARLY THIS AFTERNOON. VFR CONDITIONS EXPECTED
LATER AFTERNOON THROUGH MOST OF TONIGHT...BEFORE SURFACE TROUGH
MOVES THROUGH DURING PRE-DAWN HOURS AND MVFR CIGS RETURN.
WINDS EXPECTED TO REMAIN WEST-SOUTHWEST 220-250 DEGREES THROUGH
THIS EVENING. SUSTAINED SPEEDS EXPECTED GENERALLY 10-15 KT WITH A
FEW HIGHER GUSTS UNDER 20 KTS. WINDS SHIFT WEST-NORTHWEST 290-310
DEG AFTER TROUGH PASSAGE EARLY SATURDAY MORNING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH IN WIND DIRECTION...LOW IN GUST FREQUENCY.
* MEDIUM IN MVFR CEILING DISSIPATION TIME.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SNOW LIKELY AFTER MIDNIGHT. ACCUMULATION LIKELY.
MVFR CIGS AND IFR VIS POSSIBLE.
SUNDAY...SNOW LIKELY. MVFR/IFR LIKELY.
MONDAY...CHANCE OF SNOW SHOWERS. MVFR POSSIBLE.
TUESDAY THROUGH THURSDAY...PRIMARILY VFR.
RATZER
&&
.MARINE...
217 AM CST
MARINE WEATHER CONCERNS INCLUDE SOUTHWESTERLY GALES ACROSS NORTHERN
LAKE MICHIGAN TODAY...THEN A BRIEF PERIOD OF STRONG NORTHEAST-NORTH
WINDS 25-30 KTS OVER CENTRAL/SOUTHERN LAKE MICHIGAN SUNDAY.
A STRONG AREA OF LOW PRESSURE WAS MOVING SLOWLY EAST ACROSS FAR
NORTHERN ONTARIO EARLY THIS MORNING...WHILE A WEST-EAST ORIENTED
RIDGE OF HIGH PRESSURE WAS ACROSS THE MIDWEST REGION SOUTH OF THE
GREAT LAKES. SURFACE PRESSURE FALLS ACROSS ONTARIO AND WESTERN
QUEBEC HAVE TIGHTENED THE GRADIENT ACROSS THE NORTHERN LAKES...AND
WILL REMAIN SO INTO THIS AFTERNOON BEFORE WEAKENING AS THE LOW
REACHES JAMES BAY AND A TRAILING SURFACE TROUGH APPROACHES FROM THE
WEST. SOUTHWEST WINDS HAVE INCREASED WITH A 34 KT GUST NOTED AT PORT
INLAND MI WITHIN THE PAST HOUR...AND A GALE WARNING IS IN EFFECT FOR
THE NORTHERN HALF OR SO OF THE LAKE THROUGH MID-AFTERNOON. WINDS
WILL EASE BELOW GALE FORCE BY LATE AFTERNOON AS THE GRADIENT BEGINS
TO WEAKEN...AND WILL FURTHER DIMINISH TONIGHT.
ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP IN ASSOCIATION
WITH AN ALBERTA-CLIPPER OVER THE WEEKEND...WITH THE LOW DEEPENING
AND MOVING QUICKLY TO NORTHWEST ILLINOIS BY SUNDAY MORNING. WINDS
WILL BECOME NORTHEASTERLY SATURDAY NIGHT AS THE LOW APPROACHES...
AND ARE EXPECTED TO QUICKLY INCREASE TO NEAR 30 KT EARLY IN THE DAY
SUNDAY AS THE LOW MOVES INTO CENTRAL INDIANA. THE PERIOD OF STRONGER
WINDS APPEARS TO BE BRIEF...AS THE LOW BEGINS TO FILL AND RAPIDLY
EXITS THE REGION TO THE SOUTHEAST SUNDAY EVENING AND WEAK HIGH
PRESSURE RIDGING MOVES IN FROM THE NORTHWEST. WEAK HIGH PRESSURE
THEN LOOKS TO LINGER ACROSS THE WESTERN GREAT LAKES INTO EARLY NEXT
WEEK.
FOR THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS...BREEZY
OFFSHORE WINDS EXPECTED TODAY AND SATURDAY. SMALL CRAFT ADVISORY
CONDITIONS ARE EXPECTED TO DEVELOP QUICKLY SUNDAY MORNING DUE TO THE
STRONG WINDS FROM THE CLIPPER...WITH THE DIMINISHING NORTH FETCH
KEEPING HIGHER WAVES LINGERING INTO EARLY MONDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3
PM FRIDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
503 AM CST Fri Jan 23 2015
.SHORT TERM...(Today)
ISSUED AT 443 AM CST FRI JAN 23 2015
08z/2am IR satellite imagery shows low clouds blanketing central
Illinois, as moisture remains trapped beneath a subsidence inversion
centered around 900mb. With only very light low-level flow under
prevailing surface high pressure, am not expecting the clouds to
clear out anytime soon. HRRR suggests clouds will remain in place
through the morning, then will slowly begin to clear from west to
east during the afternoon. Based on satellite timing tools, think
clearing will be slightly faster, reaching the Illinois River Valley
by mid to late morning and the I-55 corridor by early afternoon.
The far E/NE KILX CWA around Champaign and Danville will likely
remain overcast through the entire day. High temperatures will
range from the upper 30s across the east where clouds will persist
longest to the lower 40s along/west of I-55 where sunshine will
prevail this afternoon.
&&
.LONG TERM...(Tonight through Thursday)
ISSUED AT 443 AM CST FRI JAN 23 2015
Weak short-wave trough currently evident on water vapor imagery over
southern Manitoba will drop into the Great Lakes tonight. Any light
precip associated with this feature will remain well north of
central Illinois: however, a weak frontal boundary will push through
the area, allowing winds to switch to northwesterly by morning.
Mild and dry conditions will be on tap behind the departing system
for Saturday with high temperatures topping out in the lower to
middle 40s.
Next more significant short-wave is still on target for Sunday, with
good model agreement concerning the strength and track of this
system. Surface low pressure will drop out of Canada on Saturday,
then will track from northeast Iowa Sunday morning to Ohio by Sunday
evening. With this particular track, the heaviest precipitation is
expected to remain further north along/north of the I-80 corridor.
Further south, the precip will be lighter and more scattered in
nature. Based on GFS/ECMWF timing, will introduce low chance PoPs
after midnight Saturday, with higher PoPs across the board during
the day Sunday. Atmospheric profile will remain marginal for snow,
so have only included a rain/snow mix along/north of I-74 Sunday
morning, before precip transitions to all rain by midday. May see a
change to light snow/flurries Sunday night as precip departs and
colder air returns, but no snow accumulation is expected.
After that, another wave will track well north of the area Monday
and Monday night: however, dry conditions are anticipated this far
south. Will be slightly cooler early next week as upper trough
remains in place across the eastern CONUS, resulting in highs in the
30s both Monday and Tuesday. The trough will shift eastward later
in the period, allowing temps to return to the 40s by Wednesday and
Thursday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 500 AM CST FRI JAN 23 2015
Backedge of MVFR cigs making slow progress into extreme eastern
Iowa this morning and should push into our western TAF areas
between 16 and 18z. Based on the latest movement, it appears
the clouds won`t push east of CMI until after 22z. Forecast
soundings suggest that once the skies clear, we can expect VFR
conditions thru at least the first half of tonight before a
weak frontal boundary tracks thru the region switching our
flow from southwest to northwest and ushering in another batch
of MVFR cigs for Saturday. Surface flow today will increase out
of the southwest at 10 to 15 kts and then diminish some from the
southwest early this evening before switching into the west and
northwest later tonight with speeds of 10 kts or less.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
637 AM EST FRI JAN 23 2015
.SYNOPSIS...
ISSUED AT 400 AM EST FRI JAN 23 2015
HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY BUT SKIES WILL
REMAIN CLOUDY THIS MORNING BUT A FEW BREAKS IN THE CLOUD COVER
MAY DEVELOP THIS AFTERNOON. HIGH TEMPERATURES TODAY WILL
GENERALLY BE IN THE 30S AND LOWS TONIGHT WILL GENERALLY BE IN THE
20S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EST FRI JAN 23 2015
ANOTHER QUIET SHORT TERM PERIOD WITH CLOUDS AND TEMPS THE ONLY
CONCERN. AS WE SUSPECTED LAST NIGHT...CLOUD COVER REMAINED LOCKED
IN ACROSS THE REGION THIS MORNING UNDERNEATH STRONG INVERSION WITH
WEAK FLOW. CLOUD COVER HAS BEEN EXPANDING NORTHEAST OVERNIGHT WITH
WEAK SOUTHWEST FLOW ALOFT. BACK EDGE OF CLOUD SHIELD CURRENTLY
ACROSS IA INTO MO AND THIS HAS BEEN ADVANCING SLOWLY EAST LAST FEW
HOURS. FORECAST SOUNDINGS VARY DEPENDING ON MODEL CHOICE. WRF
MODELS ALONG WITH HRRR AND RUC GENERALLY SHOW LOW LEVEL MOISTURE
AND INVERSION HANGING TOUGH THROUGH TONIGHT BEFORE CLOUD COVER
WITH NEXT SHORT WAVE ARRIVES. OTHER MODELS SHOW MUCH LESS MOISTURE
BY AFTERNOON SUGGESTING THINNING CLOUD COVER WITH BREAKS. THIS IS
ALWAYS A DILEMMA IN MID WINTER WITH WEAK MIXING AND LOW SUN ANGLE
AND SOMETIMES WE SEE THE CLEARING AND OTHER TIMES WE DO NOT. HAVE
INCREASED CLOUD COVER TODAY OVERALL WITH CLOUDY THIS MORNING BUT
DID TRY AND DEVELOP SOME BREAKS THIS AFTERNOON GIVEN SATELLITE
TRENDS AND 00Z SOUNDINGS SHOWING RELATIVELY THIN MOISTURE DEPTH.
THIS WILL IMPACT TEMPS AS OVERCAST SKIES THROUGH THE DAY WILL ONLY
ALLOW FOR A COUPLE DEGREE RISE WHILE BREAKS WOULD LEAD TO A FEW
MORE DEGREES IN WARMING. MET MOS SEVERAL DEGREES COLDER THAT MAV
AND EC GIVEN ITS PESSIMISTIC OUTPUT. HAVE OPTED TO STAY WITH A
CONSENSUS BLEND IN MIDDLE OF GUIDANCE ENVELOPE.
NEXT SHORT WAVE AND WEAK SURFACE BOUNDARY WILL APPROACH LATE
TONIGHT. NOT EXPECTING MUCH WITH THIS SYSTEM OTHER THAN CLOUDS AND A
VERY LOW CHANCE FOR SNOW SHOWERS NEAR BOUNDARY. THIS SHOULD BE
CONFINED TO EXTREME NORTHERN COUNTIES AND BASICALLY LEFT A SLIGHT
CHANCE POP IN FOR COLLABORATION LATE TONIGHT.
&&
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 401 AM EST FRI JAN 23 2015
MUCH OF THE UPCOMING LONG TERM PERIOD WILL BE CHARACTERIZED BY
PERTURBED NORTHWEST FLOW WITH THE MAIN EVENT TO WATCH STILL ON
SUNDAY. FIRST WAVE WILL SWING THROUGH THE REGION SATURDAY MORNING
AND SEND A WEAK CONVERGENT BOUNDARY ACROSS OUR CWA. A SECONDARY
EMBEDDED VORT MAX WILL THEN PASS OVER OUR AREA DURING THE AFTERNOON
AND MAY TOUCH OFF A FEW ISOLATED RAIN/SNOW SHOWERS. SYNOPTIC FORCING
IS CERTAINLY WEAK BUT FORECAST SOUNDINGS SHOW DECENT LOW LEVEL LAPSE
RATES AND PLENTY OF MOISTURE IN THE LOWEST 5 KFT. THIS RAISES SOME
CONCERN FOR FREEZING DRIZZLE BUT FORECAST SOUNDINGS ALSO SHOW AT
LEAST SOME VARYING DEGREE OF SATURATION ABOVE THE -10C LEVEL AND
SHOULD PROVIDE ENOUGH ICE NUCLEI FOR JUST SNOW. MAY EVEN BE RAIN
DURING THE AFTERNOON GIVEN SURFACE TEMPS IN THE MID TO POSSIBLY
UPPER 30S BUT WITH SURFACE DEWPOINTS HOLDING AT OR BELOW
30...SUSPECT IT WILL MAINLY FALL AS SNOW AND THEN MELT QUICKLY ON
CONTACT WITH THE GROUND. THESE WARM GROUND/SURFACE TEMPS ARE ANOTHER
REASON THAT FREEZING DRIZZLE IS NOT MUCH OF A CONCERN. BEST CHANCES
FOR PRECIP WILL BE ACROSS OUR NORTH WHERE THETA-E FLUX FROM THE
LAKES MAY PROVIDE A MARGINAL BOOST TO HYDROMETEOR PRODUCTION.
MUCH MORE ROBUST PV ANOMALY DIVES INTO THE MIDWEST BY SUNDAY...ON
THE CYCLONICALLY SHEARED SIDE OF LARGELY MERIDIONAL 130 KT UPPER
LEVEL JET. AS HAS BEEN THE CASE FOR MUCH OF THIS WINTER...MODELS
STRUGGLE WITH EXACT TRACK OF SURFACE REFLECTION AND 850MB LOW.
FORECAST IS FURTHER COMPLICATED BY SURFACE TEMPERATURES RIGHT
AROUND THE FREEZING MARK. NOTABLE SOUTHERN ADJUSTMENT SEEN IN MOST
OF THE 00Z GUIDANCE. 00Z GFS...GEM...AND ECMWF NOW TRACK THE SURFACE
LOW SOUTH OF OUR CWA WITH THE ECMWF ACTUALLY GOING THROUGH SOUTHERN
INDIANA. 00Z NAM IS NOW THE NORTHERN OUTLIER. TOUGH TO IGNORE THIS
MORE SOUTH/WEST TREND BUT CONFIDENCE IN ANY PARTICULARS REMAINS LOW
WITH PARENT JET ENERGY STILL OVER THE NORTH PACIFIC. DID RAISE POPS
AND QPF AMOUNTS QUITE A BIT IN OUR SOUTHWEST CWA. ALSO TRENDED
COLDER THOUGH STILL THINK SOME RAIN MAY CUT INTO SNOW TOTALS ACROSS
AT LEAST OUR FAR SOUTHWEST. DYNAMICS WITH THIS SYSTEM ARE NOT OVERLY
IMPRESSIVE BUT SHOULD SEE A DECENT SLUG OF 285K ISENTROPIC ASCENT
AND LOW LEVEL DEFORMATION/FGEN JUST NORTH OF THE SURFACE LOW TRACK.
GOOD MOISTURE FEED TOO...WITH LOW LEVEL MIXING RATIOS AROUND 3 G/KG
AND PWATS UP TO A HALF INCH. COUPLE THIS WITH GOOD MIDLEVEL CVA AND
UPPER LEVEL SUPPORT AND MODEL QPF VALUES OF UP TO 0.4 INCHES MAY NOT
BE TOO FAR OFF. SNOW RATIOS WILL BE ON THE LOW SIDE GIVEN WARM
GROUND AND ELEVATED/SHALLOW DGZ BUT NEVERTHELESS...ADVISORY LEVEL
SNOW COULD EASILY BE POSSIBLE FOR MOST OF OUR CWA BASED ON THE
LATEST 00Z NWP GUIDANCE. WILL GO WITH A CONSERVATIVE 2-4 INCHES FOR
NOW AND SEE WHAT THE 12Z RUNS HAVE TO OFFER.
REST OF THE FORECAST LOOKS FAIRLY BENIGN. RETURN TO COLD TEMPS
EXPECTED FOR THE FIRST HALF OF THE WORK WEEK...ESPECIALLY IF WE GET
A FRESH SNOWPACK. SINGLE DIGIT LOWS AND HIGHS AROUND 20F EXPECTED
FOR A LARGE PART OF THE CWA. POTENTIAL FOR ANOTHER WEAK CLIPPER
SYSTEM ON TUESDAY BUT AIRMASS WILL BE VERY DRY AND FORCING WEAK.
PREFER A SILENT TEN POP FOR NOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 631 AM EST FRI JAN 23 2015
MVFR CIGS REMAIN THE ISSUE TODAY. SATELLITE SHOWS EXTENSIVE AND
SOLID CLOUD DECK EXTENDING WEST TO NEAR MS RIVER AT 11Z. SLOW
EROSION WAS NOTED WITH CLEARING WORKING SLOWLY EAST. SEVERAL HIRES
MODEL SOUNDINGS INDICATE INVERSION WILL PERSIST AND LOCK LOW LEVEL
MOISTURE IN THROUGH TONIGHT. OTHER GUIDANCE SUGGEST THIN LAYER OF
MOISTURE TO MIX TODAY WITH WEAK FLOW AND SUBSIDENCE. HAVE TRIED TO
BE A BIT OPTIMISTIC WITH CIGS GRADUALLY RISING AND BECOMING BKN
THIS AFTERNOON. BROUGHT FLIGHT CATEGORY UP TO VFR BY EARLY THIS
EVENING ASSUMING BREAKS DO DEVELOP.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LASHLEY
SHORT TERM...LASHLEY
LONG TERM...AGD
AVIATION...LASHLEY
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AREA FORECAST DISCUSSION
NWS DES MOINES IA
539 AM CST FRI JAN 23 2015
...UPDATED AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 320 AM CST FRI JAN 23 2015
A NORTHWEST FLOW WILL CONTINUE THROUGH THE NEXT ONE TO TWO WEEKS.
A SERIES WEATHER SYSTEMS WILL MOVE THROUGH THE AREAS OVER THE NXT
SEVERAL DAYS.
&&
.SHORT TERM /TODAY/...
ISSUED AT 320 AM CST FRI JAN 23 2015
A WEAK TROUGH LOOKS TO QUICKLY PUSH THROUGH THE STATE LATE
THIS MORNING AND INTO THE AFTERNOON. THERE IS SOME WEAK 700-500MB
THETA-E ADVECTION AND MID-LEVEL FORCING WITH THIS CLIPPER...BUT
TREMENDOUS AMOUNT OF DRY AIR BELOW 700MB TO THE SURFACE WILL MAKE
IT DIFFICULT FOR ANY PRECIP FALLING THROUGH THIS LAYER TO REACH
THE GROUND. LOWERED POPS AND HAVE ONLY SPRINKLES MENTIONED WITH
THE LOWER CONFIDENCE OF MEASURABLE PRECIP. THE 23.03Z HOPWRF AND
LATEST HRRR HAVE A GOOD HANDLE OF THE VERY LIGHT
PRECIP/REFLECTIVITY TRENDS LATE THIS MORNING INTO THE EARLY
AFTERNOON OVER NORTHERN IOWA.
DECENT WAA AHEAD OF THE WEAK TROUGH TODAY AND WENT WELL ABOVE
GUIDANCE OVER THE CENTRAL TO SOUTH. THE RUC13 HAS A VERY GOOD
HANDLE ON THE MAX TEMPS TREND TODAY AND LEANED TOWARDS THE
23.07Z RUN. THE CLOUD COVER MOVING IN WITH THE SHORTWAVE IS THE
CAVEAT...THE QUESTION REMAINS IF CLOUD DECK WILL MOVE IN QUICK
ENOUGH TO HOLD TEMPS DOWN. LEANED TOWARD THE WAA AND ENOUGH
SUNSHINE EARLY ON IN THE DAY TO PUT TEMPS WELL INTO THE 40S...AND
THUS TWEAKED UP MAX TEMPS OVER THE SOUTHERN HALF OF THE FORECAST.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 320 AM CST FRI JAN 23 2015
TROUGH OF LOW PRESSURE FROM NWRN MN INTO CO WILL MOVE THROUGH THE
AREAS TODAY. SWLY FLOW WILL BRING WARMER AIR TO THE STATE TODAY.
THE COOLING WILL BE SHORT LIVED AS THE NEXT WEATHER DISTURBANCE
WILL MOVE THROUGH SUNDAY INTO SUNDAY EVENING. SOME DISCREPANCY
WITH THE TRACK...HOW FAR SOUTHWEST...ON IT. THE ECMWF IS AMONG THE
FARTHEST WEST...BUT EVEN SO THE TRACK IS FAR ENOUGH TO THE
NORTHEAST THAT MUCH OF IA WILL BE IN THE RAIN AREA...OR REMAIN
DRY WITH ANY FROZEN PRECIP OVER THE FAR NORTHEAST.
A STRONGER SYSTEM WILL MOVE THROUGH MID WEEK. A STRONG PUSH OF
WARM AIR IS EXPECTED AHEAD OF THIS SYSTEM AND WENT WELL ABOVE MOS
FOR HIGHS ON WED. ONCE THE SYSTEM PASSES...A TRANSITION IN THE
PATTERN WILL BEGIN. THE STORM TRACK WILL SHIFT FARTHER TO THE WEST
AND ARCTIC AIR WILL BEGIN TO SPILL INTO THE CENTRAL U.S.
&&
.AVIATION...23/12Z
ISSUED AT 536 AM CST FRI JAN 23 2015
VFR CONDITIONS WILL PREVAIL THROUGH THE FIRST 6-12 HOURS OF THE
TAF PERIOD BEFORE LOW LEVEL MOISTURE ADVECTS BACK INTO THE STATE
LATE THIS EVENING INTO SATURDAY MORNING. SOUNDINGS SUGGESTS
POTENTIAL FOR IFR CIGS BUT KEPT LOWER END OF MVFR CIGS ATTM DUE TO
LOW CONFIDENCE MENTIONING IFR/LIFR CIGS SO LATE IN THE TAF PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MS JAN 15
SHORT TERM...PODRAZIK
LONG TERM...MS JAN 15
AVIATION...PODRAZIK
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
416 AM CST FRI JAN 23 2015
.DISCUSSION...
COLD CORE UPPER TROUGH IS WELL WEST OF THE AREA BUT IT SHOULD MOVE
ACROSS THE CWA THIS EVENING/TONIGHT. DRY SLOTTING IS ALREADY
OCCURRING AND THE MANY OF THE MODELS HAVE NOT HANDLED IT VERY WELL.
THE HRRR SEEMS TO HAVE THE BEST HANDLE ON THE PRECIP KEEPING THE
VAST MAJORITY OF IT SE OF A KJSO-KELD LINE. THIS IS SUPPORTED BY
THE LATEST RADAR IMAGES WHICH SHOW THE NEXT ROUND OF RAIN ALONG
THE I-10 CORRIDOR HEADING NEWD TOWARDS THE AREA. SCATTERED AREAS
OF LIGHT RAIN ARE ONGOING THIS MORNING AND WILL LIKELY PERSIST AS
FAR NORTH AS I-30 AS DRIER AIR SLOWLY WORKS IN FROM THE NORTH.
MOST OF THE ATMOSPHERE IS BELOW FREEZING WITH THE EXCEPTION OF THE
LOWEST 2000 FEET OR SO AND SFC TEMPS ARE STILL AROUND 40 DEGREES F.
ANY SNOW THAT MAY BE FALLING WILL MOST LIKELY MELT IN THIS LOWEST
LAYER PRIOR TO REACHING THE SFC. LATEST OBS ARE SHOWING SOME
LOCATIONS IN E TX HAVE COOLED INTO THE MID 30S. THEREFORE...A FEW
FLURRIES CANNOT BE COMPLETELY RULED OUT THIS MORNING...MAINLY
NORTH OF A LINE FROM TYLER AND MARSHALL TX TO MAGNOLIA AR...BUT WITH
SFC TEMPERATURES REMAINING ABOVE FREEZING NO ACCUMULATIONS AND NO
IMPACTS ARE ANTICIPATED. ANY WINTRY PRECIP WILL TRANSITION BACK TO
ALL LIQUID RAIN LATER THIS MORNING AND THE PRECIP SHOULD MOVE EAST
AND OUT OF THE CWA THIS EVENING.
CLEARING SKIES TONIGHT COMBINED WITH COLD AND DRY AIR SHOULD
ALLOW FOR A CHILLY NIGHT TONIGHT/SATURDAY MORNING. OVERNIGHT LOWS
ALONG AND NORTH OF I-20 WILL LIKELY BE NEAR OR BELOW FREEZING. WLY
WINDS AND ABUNDANT SUNSHINE SHOULD LEAD TO A QUICK WARMING TREND
WITH DAYTIME HIGHS ABOVE 60 DEGREES AREAWIDE. NWLY FLOW ALOFT WILL
BRING THE NEXT COLD FRONT INTO THE AREA LATE MONDAY/EARLY TUESDAY.
HARDLY ANY COLD AIR ADVECTION IS EXPECTED WITH THE FRONT SO THE
ONLY REAL EFFECT ON TEMPS WILL BE TO HALT THE WARMING TREND AND
GENERALLY HOLD DAYTIME HIGHS IN THE 60S.
AN UPPER RIDGE WILL BUILD OVER THE REGION KEEPING A PERSISTENCE
FCST IN PLACE FOR MUCH OF NEXT WEEK WITH WARM AND DRY CONDITIONS
EXPECTED. THE RIDGE WILL MOVE EAST LATE NEXT WEEK AND OUR NEXT
RAIN CHANCES WILL LIKELY BE NEXT FRIDAY AND INTO THE WEEKEND AS
THE FLOW ALOFT TRANSITION BACK TO NWLY AND A COLD FRONT MOVES INTO
THE CWA AND BECOMES STATIONARY. /09/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 44 32 57 37 65 / 50 10 0 0 0
MLU 43 32 57 37 64 / 50 30 0 0 0
DEQ 48 28 57 33 62 / 20 0 0 0 0
TXK 46 31 56 36 63 / 40 10 0 0 0
ELD 43 31 57 36 62 / 50 20 0 0 0
TYR 47 33 57 37 65 / 40 10 0 0 0
GGG 45 32 57 36 65 / 40 10 0 0 0
LFK 45 35 59 37 65 / 50 10 0 0 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
09
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
542 AM CST FRI JAN 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 421 AM CST FRI JAN 23 2015
SHORT TERM CONCERN REMAINS THE THREAT OF FREEZING RAIN/SLEET MOVING
ACROSS THE NORTHERN AND EASTERN CWA MAINLY THROUGH THIS MORNING.
CURRENT RADAR TRENDS INDICATE MODELS MAY BE DOWNPLAYING EXTENT OF
FREEZING RAIN THREAT. WILL FOLLOW A COMBO RAP ISENTROPIC
ANALYSIS (290K/295K LAYERS) AND HRRR TREND FOR POPS THIS AM.
STILL LOOKS THE BEST THREAT REMAINS ALONG AND NORTH OF THE I94
CORRIDOR. WILL LET THE ADV EXPIRE TO THE FAR WEST THROUGH 15Z AND
IN THE EAST BY 18Z. ROAD TEMPERATURE ARE CURRENTLY AROUND 30F IN
THE NORTHERN CWA AND COOLER INTO THE SOUTHERN PORTION OF THE AREA.
SURFACE DEWPTS ARE IN THE LOWER 20S TO THE SOUTH WILL BOTH HELP
AND HINDER FREEZING RAIN THREAT. MAY TAKE SOME TIME TO SATURATE
THE FARTHER SOUTH THE AREA OF PRECIPITATION MOVES THIS MORNING. IF
IT DOES PRECIPITATE...SOME COOLING FROM THE DRIER AIR WILL ENHANCE
THE FREEZING RAIN THREAT ON UNTREATED ROADS/BRIDGES.
TEMPERATURES SHOULD WARM ABOVE FREEZING THROUGH NOON MOST AREAS
ENDING THE FREEZING RAIN THREAT. THIS SYSTEM EXITS TO THE EAST BY
THIS EVENING WITH CLOUDS REMAINING THROUGH THE NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 421 AM CST FRI JAN 23 2015
THE LONG TERM BEGINS SATURDAY TRANQUIL AROUND HERE...BUT A STRONG
NOR EASTER WILL BE PUSHING UP THE EAST COAST WHILE A RIDGE BUILDS
UP THE WEST COAST. BOTH WILL IMPACT THE CLIPPER SET TO DIVE INTO
THE UPPER MIDWEST SATURDAY NIGHT. MODELS HAVE TRENDED SHARPER WITH
THE WAVE WHICH RESULTS IN A WESTWARD SHIFT SIMILAR TO WHAT WAS
SEEN WEDNESDAY NIGHT. GIVEN THE SYNOPTIC SET UP...THIS IS THE
PREFERRED TREND. 00Z NAM WAS FLATTEST AND MUCH FURTHER EAST THAN
THE REST OF THE GUIDANCE AND WAS IGNORED. THE GFS/CANADIAN SEEM
LIKE THE BEST COMPROMISE WITH THE ECMWF A BIT TOO FAST AND
CONSIDERABLY LIGHTER WITH ITS PRECIP. 06Z NAM HAS TRENDED FURTHER
WEST CLOSER TO THE 00Z GFS AND CANADIAN. AT THIS STAGE...IT IS
UNLIKELY THE TRACK WILL SHIFT SIGNIFICANTLY EAST...BUT IT COULD
STILL TREND SLIGHTLY WEST.
THE TRACK OF THE LOW WILL PLAY A SIGNIFICANT ROLE IN WHO SEES THE
MOST ACCUMULATION. A GOOD BAND OF SNOW WILL SET UP ALONG AND JUST
EAST OF THE LOW...WITH SOME POTENTIAL FOR DRY SLOTTING ON THE WEST
SIDE. IT WILL BE A QUICK MOVER...SO ONLY EXPECTING ABOUT 6-9 HOURS
OF ACCUMULATING SNOWFALL. A GENERAL 2-4 INCHES APPEAR LIKELY
WITHIN THE HEART OF THE BAND WITH AMOUNTS GRADUALLY TAPERING OFF
TO THE EAST AND QUICKLY TAPERING OFF TO THE WEST. CURRENTLY...THE
HEAVIEST AXIS OF SNOW IS FORECAST TO SET UP FROM NORTHWEST MN TO
EAST CENTRAL MN AND SOUTHWEST WI. FLURRIES MAY PERSIST INTO
SUNDAY MORNING BUT A SURFACE RIDGE AXIS WILL BUILD IN SUNDAY
AFTERNOON.
ANOTHER CLIPPER WILL BRING A BAND OF LIGHT SNOW ACROSS MN SUNDAY
NIGHT AND INTO WISCONSIN BY MONDAY. THIS WILL BE A SLOWER MOVER
SINCE THE FIRST CLIPPER WILL BE DEVELOPING OFF THE EAST COAST. A
PROLONGED PERIOD OF LIGHT SNOW OR FLURRIES COULD DEVELOP OVER THE
EASTERN AREAS DURING THIS TIME. ACCUMULATIONS WILL BE LIGHTER THAN
WITH THE FIRST SYSTEM.
A PATTERN SHIFT WILL TAKE PLACE TUESDAY AND WEDNESDAY WITH THE
RIDGE BUCKLING TO THE NORTHEAST. A SHOT OF WARMTH WILL SURGE INTO
THE UPPER MIDWEST THANKS TO A 50+ KT 850 MB JET BRINGING +10 TO
+13C AIR IN. GUIDANCE IS WAY TOO COLD IN SUCH A PATTERN...AND
NUDGED TEMPS UP SEVERAL DEGREES. MAY CRACK 50+ ACROSS WRN MN AND
MID TO POSSIBLY UPPER 40S FURTHER EAST.
COLD FRONT WILL DROP SOUTH FOR LATE WEEK AS THE PATTERN SHIFTS
TOWARD SOMETHING MORE COMMON DURING THE LAST YEAR. LUCKILY FOR
US...THE COLDEST SURGE OF ARCTIC AIR WILL ROTATE EAST INTO NEW
ENGLAND AND GIVE US A GLANCING BLOW. EVEN WITH THIS...TEMPS WILL
STILL REMAIN NEAR AVERAGE THURSDAY AND FRIDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 527 AM CST FRI JAN 23 2015
CURRENT RADAR AND MODEL TRENDS CONTINUE TO DROP BAND OF LIGHT
FREEZING RAIN AND SOME SLEET SOUTHEAST OVER THE NORTHEAST CWA
THROUGH 18Z. BEST CHANCES OF THIS OCCURRING AT KSTC-KRNH AND KEAU
THROUGH 18Z. KMSP WILL BE ON THE EDGE OF THE ACTIVITY...BUT STILL
THREAT REMAINS IN THE 14Z-17Z PERIOD. AREA DROPS SOUTHEAST AND
EXITS BY THE AFTERNOON.
NEXT PROBLEM IS THE MVFR CIG THREAT DEVELOPING LATER THIS
AFTERNOON AND TONIGHT. FOLLOWED A SLOWER SREF PROGRESSION FOR
THIS. SHALLOW RH LAYER ON BUFKIT PROFILES SO THERE IS A CHANCE OF
JUST SCT LOWER CLOUDS INTO THE EVENING. WILL HAVE TO MONITOR CLOUD
TRENDS AS ANY REAL LOW CLOUDS RESIDE ALONG THE MN/CANADIAN BORDER.
HIGHER CONFIDENCE IN LOW END MVFR CIGS DEVELOPING INTO THE
EVENING. SURFACE WINDS SOUTHWEST BECOMING MORE WEST/NORTHWEST WITH
PASSAGE OF SURFACE TROUGH TODAY.
KMSP...
STILL OUR CONFIDENCE IS NOT 100% FOR FREEZING RAIN OR SLEET
OCCURRING AT THE AIRPORT. WE CONTINUE TO THINK THE CHANCE IS HIGH
ENOUGH TO INCLUDE THE FREEZING PRECIP IN THE TAF. ANY PRECIP THAT
DOES OCCUR WILL BE LIGHT AND MAY NOT MEASURE. RUNWAY TEMPERATURES
REMAIN 28-30 WITH AIR TEMPERATURE AROUND 30. SOME SLIGHT UPWARD
TREND IN THESE READING SWILL OCCUR THIS MORNING. BUT WILL BE
CRITICAL WHEN GREATEST PSPN THREAT OCCURS...WHICH REMAINS
14Z-17Z FOR KMSP. CONTINUE TO EXPECT MVFR CIGS DEVELOPING LATER
THIS AFTERNOON BEHIND THE TROUGH PASSAGE. THESE LOWER END MVFR
CIGS SHOULD CONTINUE THROUGH THE NIGHT INTO SATURDAY.
/OUTLOOK FOR KMSP/
SATURDAY NIGHT...BECOMING MVFR. CHC IFR CIGS/VSBYS -SN MAINLY
AFTER 06Z SUN. WIND W 5-10 KTS.
SUNDAY...MVFR WITH -SN/IFR POSSIBLE. WIND NW 10G20 KTS.
MONDAY...VFR. WIND SW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ043>045-
049>053-061-063.
WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ041-
042-048.
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ014>016-023-
025-027.
&&
$$
SHORT TERM...DWE
LONG TERM...BORGHOFF
AVIATION...DWE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
421 AM CST FRI JAN 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 421 AM CST FRI JAN 23 2015
SHORT TERM CONCERN REMAINS THE THREAT OF FREEZING RAIN/SLEET MOVING
ACROSS THE NORTHERN AND EASTERN CWA MAINLY THROUGH THIS MORNING.
CURRENT RADAR TRENDS INDICATE MODELS MAY BE DOWNPLAYING EXTENT OF
FREEZING RAIN THREAT. WILL FOLLOW A COMBO RAP ISENTROPIC
ANALYSIS (290K/295K LAYERS) AND HRRR TREND FOR POPS THIS AM.
STILL LOOKS THE BEST THREAT REMAINS ALONG AND NORTH OF THE I94
CORRIDOR. WILL LET THE ADV EXPIRE TO THE FAR WEST THROUGH 15Z AND
IN THE EAST BY 18Z. ROAD TEMPERATURE ARE CURRENTLY AROUND 30F IN
THE NORTHERN CWA AND COOLER INTO THE SOUTHERN PORTION OF THE AREA.
SURFACE DEWPTS ARE IN THE LOWER 20S TO THE SOUTH WILL BOTH HELP
AND HINDER FREEZING RAIN THREAT. MAY TAKE SOME TIME TO SATURATE
THE FARTHER SOUTH THE AREA OF PRECIPITATION MOVES THIS MORNING. IF
IT DOES PRECIPITATE...SOME COOLING FROM THE DRIER AIR WILL ENHANCE
THE FREEZING RAIN THREAT ON UNTREATED ROADS/BRIDGES.
TEMPERATURES SHOULD WARM ABOVE FREEZING THROUGH NOON MOST AREAS
ENDING THE FREEZING RAIN THREAT. THIS SYSTEM EXITS TO THE EAST BY
THIS EVENING WITH CLOUDS REMAINING THROUGH THE NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 421 AM CST FRI JAN 23 2015
THE LONG TERM BEGINS SATURDAY TRANQUIL AROUND HERE...BUT A STRONG
NOR EASTER WILL BE PUSHING UP THE EAST COAST WHILE A RIDGE BUILDS
UP THE WEST COAST. BOTH WILL IMPACT THE CLIPPER SET TO DIVE INTO
THE UPPER MIDWEST SATURDAY NIGHT. MODELS HAVE TRENDED SHARPER WITH
THE WAVE WHICH RESULTS IN A WESTWARD SHIFT SIMILAR TO WHAT WAS
SEEN WEDNESDAY NIGHT. GIVEN THE SYNOPTIC SET UP...THIS IS THE
PREFERRED TREND. 00Z NAM WAS FLATTEST AND MUCH FURTHER EAST THAN
THE REST OF THE GUIDANCE AND WAS IGNORED. THE GFS/CANADIAN SEEM
LIKE THE BEST COMPROMISE WITH THE ECMWF A BIT TOO FAST AND
CONSIDERABLY LIGHTER WITH ITS PRECIP. 06Z NAM HAS TRENDED FURTHER
WEST CLOSER TO THE 00Z GFS AND CANADIAN. AT THIS STAGE...IT IS
UNLIKELY THE TRACK WILL SHIFT SIGNIFICANTLY EAST...BUT IT COULD
STILL TREND SLIGHTLY WEST.
THE TRACK OF THE LOW WILL PLAY A SIGNIFICANT ROLE IN WHO SEES THE
MOST ACCUMULATION. A GOOD BAND OF SNOW WILL SET UP ALONG AND JUST
EAST OF THE LOW...WITH SOME POTENTIAL FOR DRY SLOTTING ON THE WEST
SIDE. IT WILL BE A QUICK MOVER...SO ONLY EXPECTING ABOUT 6-9 HOURS
OF ACCUMULATING SNOWFALL. A GENERAL 2-4 INCHES APPEAR LIKELY
WITHIN THE HEART OF THE BAND WITH AMOUNTS GRADUALLY TAPERING OFF
TO THE EAST AND QUICKLY TAPERING OFF TO THE WEST. CURRENTLY...THE
HEAVIEST AXIS OF SNOW IS FORECAST TO SET UP FROM NORTHWEST MN TO
EAST CENTRAL MN AND SOUTHWEST WI. FLURRIES MAY PERSIST INTO
SUNDAY MORNING BUT A SURFACE RIDGE AXIS WILL BUILD IN SUNDAY
AFTERNOON.
ANOTHER CLIPPER WILL BRING A BAND OF LIGHT SNOW ACROSS MN SUNDAY
NIGHT AND INTO WISCONSIN BY MONDAY. THIS WILL BE A SLOWER MOVER
SINCE THE FIRST CLIPPER WILL BE DEVELOPING OFF THE EAST COAST. A
PROLONGED PERIOD OF LIGHT SNOW OR FLURRIES COULD DEVELOP OVER THE
EASTERN AREAS DURING THIS TIME. ACCUMULATIONS WILL BE LIGHTER THAN
WITH THE FIRST SYSTEM.
A PATTERN SHIFT WILL TAKE PLACE TUESDAY AND WEDNESDAY WITH THE
RIDGE BUCKLING TO THE NORTHEAST. A SHOT OF WARMTH WILL SURGE INTO
THE UPPER MIDWEST THANKS TO A 50+ KT 850 MB JET BRINGING +10 TO
+13C AIR IN. GUIDANCE IS WAY TOO COLD IN SUCH A PATTERN...AND
NUDGED TEMPS UP SEVERAL DEGREES. MAY CRACK 50+ ACROSS WRN MN AND
MID TO POSSIBLY UPPER 40S FURTHER EAST.
COLD FRONT WILL DROP SOUTH FOR LATE WEEK AS THE PATTERN SHIFTS
TOWARD SOMETHING MORE COMMON DURING THE LAST YEAR. LUCKILY FOR
US...THE COLDEST SURGE OF ARCTIC AIR WILL ROTATE EAST INTO NEW
ENGLAND AND GIVE US A GLANCING BLOW. EVEN WITH THIS...TEMPS WILL
STILL REMAIN NEAR AVERAGE THURSDAY AND FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1142 PM CST THU JAN 22 2015
VFR TONIGHT...WITH A BAND OF LIGHT FREEZING RAIN OR SLEET COMING
THROUGH BETWEEN 12-18Z THIS MORNING...FOLLOWED BY MVFR CEILINGS IN
THE AFTERNOON AND EVENING. THE PRECIP SHOULD BE LIGHT AND AFFECT
AREAS PRIMARILY NEAR AND NORTH OF THE I-94 CORRIDOR.
UNFORTUNATELY...THAT MEANS MOST TAF SITES /BESIDES KAXN AND KRWF/
HAVE A 1-2 HOUR WINDOW WHERE LIGHT SLEET OR LIGHT FREEZING RAIN IS
POSSIBLE. TEMPS ARE EXPECTED TO GET ABOVE FREEZING BY THE LATE
MORNING AND EARLY AFTERNOON. SO...ANY SLICK SPOTS ON RUNWAYS
SHOULD MELT THIS AFTERNOON. THE MVFR CEILINGS SHOULD ARRIVE BEHIND
THE PRECIP FOR THE 2ND HALF OF THE TAF PERIOD.
KMSP...
WE`RE NOT 100% CONFIDENT IN FREEZING RAIN OR SLEET AT THE
AIRPORT...BUT IF IT MISSES KMSP...IT WILL NOT BE BY MUCH. WE THINK
THE CHANCE IS HIGH ENOUGH TO INCLUDE THE FREEZING PRECIP IN THE
TAF AT THIS POINT. THIS PRECIP...HOWEVER...SHOULD COME AFTER THE
HIGHER TRAFFIC THIS MORNING. THERE WILL DEFINITELY BE MORE STUFF
SHOWING UP ON RADAR TO THE NORTH AND EAST OF THE AIRPORT. KMSP
WILL BE ON THE SOUTHERN END OF THE PRECIP.
/OUTLOOK FOR KMSP/
SATURDAY...VFR. WIND W 5-10 KTS.
SUNDAY...MVFR WITH -SN/IFR POSSIBLE. WIND NW 10G20 KTS.
MONDAY...VFR. WIND SW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ043>045-
049>053-061-063.
WINTER WEATHER ADVISORY UNTIL 9 AM CST THIS MORNING FOR MNZ041-
042-048.
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ014>016-023-
025-027.
&&
$$
SHORT TERM...DWE
LONG TERM...BORGHOFF
AVIATION...CLF
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
917 AM CST Fri Jan 23 2015
.UPDATE:
Issued at 911 AM CST Fri Jan 23 2015
In the process of updating forecast to reflect a slower clearing
across the CWA. Will be tweaking sky trends to more closely reflect
14z RUC 925MB RH progs...which suggests clouds will still be
holding tough over the eastern half of the CWA at 18z. However,
think that clearing will make it into our eastern counties by late
afternoon as dry air is advected east by increasing westerly low
level winds.
Truett
&&
.SHORT TERM: (Through Late This Afternoon)
Issued at 240 AM CST Fri Jan 23 2015
A low pressure system moving through the southern CONUS will have
very little effect on today`s weather except for an increase in high
level clouds across the southern CWA. Highs in the 40s will be above
average for mid to late January.
Kanofsky
.LONG TERM: (Tonight through Thursday)
Issued at 240 AM CST Fri Jan 23 2015
A storm system centered over western TX, yet having influence well
to its east across much of the deep South, is expected to move to
the east over the next 24 hours and not have much of an impact for
our region. As a result, quiet wx is forecast for tonight.
Intermittent periods of clouds and not a particularly strong cold
front later will yield min temps above normal for this time of year,
with mid-upper 20s.
In this storm system`s wake beginning later tonight, we will see a
resumption of the familiar winter pattern of NW flow and this is
expected to last thru Tuesday of next week. There is really only
one system of any note during this period, and that is a strong
clipper system that has been discussed at length for several days
now. This clipper system is still on track to impact our region
primarily on Sunday. Model diffs continue to exist on the track and
structure, with the NAM the biggest outlier, and least reliable on
Day 3. The EC and GFS solutions are greatly preferred here. They
feature an initial strong disturbance that cuts into northwest MO
thru dawn Sunday, with the energy then splitting in two: the
northern portion tracking almost due east to Cincinnati, OH by early
Sunday evening, and the southern portion continuing to dig
southeastward to Memphis, TN. The initial phase thru dawn on Sunday
has a unified broadscale lift to it across the entire region at some
point, but with all of the moisture of any note on the very backside
of the region of lift. What should be anticipated from this is a
brief shot of pcpn for most locations but will struggle to measure.
Have broad-brushed low PoPs for virtually the entire forecast area.
Pcpn-types are expected to be liquid for this with boundary layer
temps too warm, not being helped out at all from SW winds at the
time. By Sunday daytime, the split in the system will result in the
high PoP/accumulating snow region to extend well to our
northeast--from Chicago, IL to northern OH--with once again a
broad-brushed region of low PoPs extending well to the south where
an invigorated broadscale lift region during mainly the morning and
midday hours will largely be cancelled out by moisture loss.
Boundary layer temps will once again preclude snow in the low PoP
region over us, with only spotty light rain expected. The system
should be gone and well east by nightfall Sunday. Prefer GFS QPF
with a hundredth or two only with EC too high on its values.
A weak front late Monday may result in a threat for light pcpn, but
prefer to wait for another model iteration before adding any
mention, otherwise dry until the middle of next week.
Temps will be primarily a tug of war between above normal and a
return to seasonable values with what few cold air intrusions there
will be.
An even milder period looks on tap for Wednesday and Thursday next
week with an upper level ridge building overhead and S-SW flow at
the surface.
TES
&&
.AVIATION: (For the 12z TAFs through 12z Saturday Morning)
Issued at 537 AM CST Fri Jan 23 2015
Specifics for KUIN: MVFR stratus in place should eventually advect
eastward today, leaving VFR conditions for most of the afternoon
and evening. Some lower clouds may accompany a cold front when it
moves through after 24/06z.
Specifics for KCOU: MVFR stratus has locally cleared out near KCOU
however a lingering batch was located upstream. It may produce
MVFR conditions at KCOU at times until it starts to dissipate.
Thereafter, expect a prolonged period of VFR conditions until a
cold front arrives late tonight after 24/09z. Some lower clouds
may accompany the front.
Specifics for KSTL, KCPS, KSUS: Back edge of MVFR stratus has
been making slow progress eastward, but new westward development
over south central MO does raise some doubts about how quickly the
stratus will clear out. Once it does clear out, though, expect
several hours of VFR conditions before low-end VFR or high-end
MVFR cigs arrive with a cold front after 24/10z.
Kanofsky
&&
.LSX WATCHES/WARNINGS/ADVISORIES:
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS RALEIGH NC
900 AM EST FRI JAN 23 2015
.SYNOPSIS...HIGH PRESSURE WILL BUILD ACROSS VA AND NC THIS MORNING.
MEANWHILE...A LOW PRESSURE SYSTEM WILL TRACK JUST INLAND OF THE
SOUTHEAST US COAST THROUGH TONIGHT...THEN OFFSHORE THE MIDDLE
ATLANTIC AND NEW ENGLAND COAST ON SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 900 AM FRIDAY...
THE 12Z/GSO SOUNDING WAS WELL REPRESENTATIVE OF THE CURRENT
TEMPERATURE PROFILE THROUGHOUT THE NORTHWEST PIEDMONT. THIS PROFILE
IS SUPPORTIVE OF BRIEF/NUISANCE LIGHT SNOW/SLEET MIXED WITH THE
RAIN AT PRECIP ONSET THIS MORNING IN THE NW PIEDMONT. HOWEVER...
SURFACE TEMPERATURES ARE WELL INTO THE 30S (ABOVE FREEZING)... AND
THE WET BULB TEMPERATURES ALSO JUST ABOVE FREEZING IN
FORSYTH AND NW GUILFORD INTO PERSON (OUR COLDEST COUNTIES). RADAR
INDICATED PRECIPITATION WAS RAPIDLY DEVELOPING OVER WESTERN NORTH
CAROLINA. THE PRECIPITATION WAS FALLING AS A LIGHT MIXTURE OF
SNOW/SLEET OVER THE NORTHERN MOUNTAINS AND NORTHERN FOOTHILLS...
WITH A LIGHT SNOW/SLEET/RAIN MIXTURE INTO DAVIDSON/FORSYTH COUNTIES.
IT IS ALONG THE LEADING EDGE OF THE PRECIPITATION SHIELD WHERE JUST
ENOUGH COLD DRY AIR WAS IN PLACE OVER NW NC COURTESY OF THE 1028 MB
SURFACE HIGH PRESSURE OVER PA... EXTENDING INTO NC/SC. THIS HIGH IS
RAPIDLY RETREATING AND THIS IS VERY UNFAVORABLE FOR ADDITIONAL COLD
DRY AIR DELIVERY INTO OUR REGION TO SUPPORT ANY SNOW/SLEET
ACCUMULATION IN OUR REGION. THE WARMING ALOFT WILL SWEEP IN FROM THE
SOUTH AND EAST QUICKLY TAKING TEMPERATURES INTO THE 40S AT 5K FEET
THIS AFTERNOON. THIS WILL END ANY SNOW/SLEET... AND KEEP IT AS A
NUISANCE ON THE LEADING EDGE OF THE EXPANDING PRECIP FIELD. ONCE WE
REACH SATURATION IN THE BOUNDARY LAYER... FORECAST WET BULBS ARE TO
REMAIN IN THE 33-35 RANGE TODAY.
THEREFORE... BOTTOM LINE... LIGHT SNOW/SLEET/RAIN MIX AT
PRECIPITATION ONSET IN THE NW AND N PIEDMONT... ROUGHLY WEST AND
NORTH OF A LINE FROM DAVIDSON AND RANDOLPH COUNTIES NE TO PERSON
COUNTY... NO SNOW/SLEET ACCUMULATION EXPECTED. AS THE COLUMN
SATURATES WITH THE PRECIPITATION FALLING FOR 1-3 HOURS... THE
PRECIPITATION WILL BE ALL RAIN WITH TEMPS EXPECTED TO HOLD NEAR THE
WET BULB READINGS IN THE MID 30S THROUGHOUT THE TRIAD REGION. THIS
IS SAFELY ABOVE FREEZING. THEN OVERNIGHT... TEMPS WILL REMAIN STEADY
OF EVEN RISE A FEW DEGREES DUE TO THE OVERWHELMING WARMING ALOFT AND
RAIN. -BADGETT
PREVIOUS DISCUSSION ISSUED AT 300 AM...
A POSITIVELY TILTED TROUGH OVER THE SOUTHERN PLAINS WILL CONTINUE
TO MOVE EAST ACROSS THE GULF COAST STATES TODAY AND THEN BEGIN TO
LIFT ACROSS THE CAROLINAS LATER TONIGHT. CYCLOGENESIS APPEARS TO BE
UNDERWAY SOUTH OF NEW ORLEANS THIS MORNING... AND THIS LOW FORECAST
IS TO TRACK ACROSS SOUTHERN GEORGIA AND UP THE CAROLINA COASTAL AREA
TONIGHT.
A LARGE AREA RAIN IS CURRENTLY SPREADING ACROSS ALABAMA AND
GEORGIA...WITH A FEW RADAR ECHOES AND TRACE REPORTS AS FAR EAST AS
AIKEN GEORGIA...BUT THE LEADING EDGE STILLS APPEARS TO BE DWINDLING
AS IT ENCOUNTERS THE DRIER AIR ASSOCIATED WITH A 1030MB SURFACE HIGH
CENTERED OVER SOUTHEAST VIRGINIA. THE HRRR HAS A PRETTY GOOD HANDLE
ON THIS AND SUGGESTS MEASURABLE PRECIP MAY REACH THE SOUTHERN
PIEDMONT BY 15Z. THE WETBULB FREEZING LINE IS CURRENTLY NEAR
HIGHWAY 64 AND SHOULDN`T MOVE MUCH MORE TO THE SOUTH AS MID CLOUDS
CONTINUE TO POUR IN FROM THE WEST AND TEMPS STABILIZE. RAP
SOUNDINGS SHOW JUST ENOUGH WARMING PRIOR TO THE ARRIVAL OF PRECIP TO
KEEP ALL PRECIP LIQUID AT ONSET.
ISENTROPIC LIFT REALLY INCREASES BY 18Z AND EXPECT RAIN TO BE
WIDESPREAD ACROSS THE ENTIRE AREA AFTER 21Z....WITH THE HEAVIEST
RAINFALL OCCURRING BETWEEN 00Z AND 06Z AS A 50KT LOW LEVEL JET
SURGES ACROSS CENTRAL AND EASTERN NC. THERE ARE STILL SOME
DIFFERENCE IN THE TRACK OF THE SURFACE LOW...THE ECMWF A GOOD 50 TO
75 MILES FURTHER INLAND THAN THE GFS. PREFERENCE IS FOR THE MORE
EASTERN TRACK OF THE GFS AND NAM GIVEN THAT A STRONG CAD AIRMASS
WILL DEVELOP IN RESPONSE TO THE RAIN THIS AFTERNOON. THE WEDGE FRONT
WILL LIKELY SHIFT INLAND AS THE LOW APPROACHES BUT THE TRUE WARM
SECTOR SHOULD REMAIN CONFINED TO THE COAST WHERE ANY SEVERE THREAT
WOULD ALSO REMAIN.
MODEL QPF IS RATHER HIGH TONIGHT...WITH AS MUCH AS ONE INCH IN THE
WEST AND NEAR 2 INCHES EAST OF I-95...AND THIS SEEMS VERY REASONABLE
GIVEN PW INCREASING TO AS MUCH AS 200 PERCENT OF NORMAL AND A
PLETHORA OF 1 TO 2 INCH TOTALS ALREADY REPORTED UPSTREAM ACROSS
LOUISIANA AND MISSISSIPPI. CONTEMPLATED A FLOOD WATCH GIVEN RECENT
RAINFALL EVENTS AND SOIL MOISTURE...BUT WITHOUT CONVECTION THE
FLOODING MAY MAY ISOLATED TO SOME OF THE SMALL CREEKS AND STREAMS
THAT ARE ALREADY RUNNING HIGHER THAN NORMAL. SOME MINOR RIVER
FLOODING IS ALSO POSSIBLE ON THE NEUSE AND TAR RIVERS.
TEMPS WILL RISE A LITTLE TODAY...MORE SO IN THE EAST...BUT AS PRECIP
MOVES IN THEY WILL LEVEL OFF OR EVEN DROP A BIT...WITH HIGHS INLY
REACHING THE MID 30S NORTHWEST TO MID 40S SOUTHEAST. TEMPS WON`T
CHANGE MUCH OVERNIGHT...DROPPING MAYBE 2 TO 3 DEGREES.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...
MODELS DEPICT A BRIEF PERIOD OF MID-LEVEL DRYING AS A DRY SLOT
SURGES ACROSS THE AREA LATE TONIGHT...BUT THE ARRIVAL OF THE UPPER
TROUGH AND STRONGER DCVA SHOULD CAUSE PRECIP TO REDEVELOP OR
REINTENSIFY EARLY SATURDAY...MAINLY ACROSS THE EASTERN HALF OF THE
AREA. RAINFALL TOTALS MAY NOT BE AS HIGH WITH THE SURFACE LOW
HAVING MOVED OFF TO THE NORTHEAST...BUT MODELS SHOW ANOTHER HALF
INCH POSSIBLE PRIOR TO 15Z. PRECIP WILL THEN END FOR MUCH OF THE
AREA AS MORE PRONOUNCED DRYING ALOFT DEVELOPS. HOWEVER... A
DEFORMATION BAND EXPECTED TO DEVELOP OVER THE TENNESSEE VALLEY WILL
PIVOT ACROSS AT LEAST THE NORTHERN HALF OF THE AREA AROUND MIDDAY.
RAPID MID-LEVEL COOLING AND RESATURATION OF THE ICE-NUCLEATION ZONE
SUGGESTS RAIN COULD MIX WITH OR CHANGE OVER TO SNOW WITHIN THIS
BAND...BUT FORECAST SOUNDINGS HAVE THE LOWEST 2000 FT OF THE
BOUNDARY LAYER ABOVE FREEZING AND THIS MAY BE TOO MUCH MELTING TO
OVERCOME. WILL BE INTERESTING TO SEE HOW THIS UNFOLDS...THOUGH NO
IMPACTS WOULD BE EXPECTED.
THE BAND SHOULD DEPART THE NORTHEAST CWA BY 18Z TO 21Z...WITH CLEAR
SKIES BY 00Z TO 03Z. COLD ADVECTION WILL BE RELATIVELY STRONG
SATURDAY EVENING...RESULTING WIND GUSTS OF 20-25MPH FOR THE FIRST
HALF OF THE NIGHT. LOWS WILL DROP INTO THE LOW TO MID 30S. -BLS
SUN AND SUN NIGHT: A STRONG PACIFIC JET WILL ROUND A WESTERN CONUS
RIDGE AND CAUSE AN ASSOCIATED NORTHERN STREAM SHORTWAVE TROUGH TO
AMPLIFY SHARPLY FROM THE NORTHERN PLAINS TO THE CAROLINAS AND VA
THROUGH SUN NIGHT. A CLIPPER SURFACE LOW WILL ACCOMPANY THE
SHORTWAVE TROUGH AND CROSS THE UPPER MIDWEST AND OH VALLEY SUN AND
THE CENTRAL APPALACHIANS AND MIDDLE ATLANTIC STATES SUN NIGHT. WSW
LOW LEVEL FLOW AHEAD OF THE CLIPPER LOW...AND IN BRIEF SHORTWAVE
RIDGING BETWEEN THIS SHORTWAVE TROUGH AND AN INTENSE CYCLONE
APPROACHING NOVA SCOTIA (OUR FRI-SAT WEATHER MAKER)...WILL RESULT IN
A MOSTLY SUNNY AND MILD DAY IN THE 50S TO END THE WEEKEND.
THE PASSAGE OF THE SHORTWAVE TROUGH AND ASSOCIATED COLD POOL ALOFT
CHARACTERIZED BY H5 TEMPERATURES AROUND MINUS 30 - AND POCKET OF MID
LEVEL LAPSE RATES AROUND 7 C/KM - WILL CAUSE AN AREA OF SHOWERS TO
PIVOT EAST ACROSS CENTRAL NC OVERNIGHT. ALL LIQUID IS ANTICIPATED
OWING TO A 1500-3000 FT DEEP ABOVE FREEZING BOUNDARY LAYER...LOWEST
AND COLDEST ONCE THE SHOWERS ARE MOVING OUT. LOWS...AND WITH
CLEARING SPREADING INTO THE PIEDMONT BY DAYBREAK...WITHIN A FEW
DEGREES EITHER SIDE OF 35. -MWS
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 345 AM FRIDAY...
JUST AS QUICKLY AS THE CLOUDINESS AND SHOWERS ASSOCIATED WITH THE
"ALBERTA CLIPPER"/NORTHERN STREAM SHORTWAVE WAVE MOVE OUT...
ADDITIONAL SHEAR VORTICITY IN FAST NW FLOW ALOFT WILL AMPLIFY INTO
THE TROUGH BASE...TO NEAR AND JUST OFFSHORE THE COAST OF THE
CAROLINAS...THROUGH WED MORNING. TYPICAL MEDIUM RANGE TIMING AND
AMPLITUDE DISTANCES BECOME MAGNIFIED DURING THIS TIME...WITH THE 00Z
ECMWF REPRESENTING THE SOUTHERNMOST - AND CONSEQUENTLY RELATIVELY
WETTEST FOR CENTRAL NC - SOLUTIONS FOR THE PERIOD MON-TUE. BASED ON
A PREFERRED SLIGHTLY LESS AMPLIFIED/MORE NORTHWARD CONSENSUS OF
MODEL CLUSTERING REPRESENTED WELL BY THE 00Z GFS...THE RELATIVE
HIGHEST PROBABILITY OF PRECIPITATION (IN THE CHANCE RANGE) SHOULD BE
CENTERED TOWARD THE NORTHEAST PIEDMONT WITH THE ARRIVAL OF THE LEAD
SHEAR VORTICITY AND POSSIBLE INTERACTION WITH A LOW LEVEL MOIST AXIS
OVER EASTERN NC THROUGH MON NIGHT. ANY PRECIPITATION THAT WERE TO
FALL AFTER DARK MON...AFTER TEMPERATURES PEAK IN THE UPPER 40S TO
LOWER 50S...WOULD BE IN THE FORM OF LIGHT SNOW OWING TO STRONG DEEP
LAYER COOLING MON NIGHT - A CASE OF "THE COLD AIR CHASING THE
MOISTURE".
TRAILING SHEAR VORTICITY WILL CARVE THE TROUGH OFF THE COAST OF THE
CAROLINAS TUE-TUE NIGHT. ASSOCIATED RE-STEEPENING OF THE LAPSE RATES
ALOFT...AND LIFT/MOISTENING OF THE COLUMN...WILL RESULT IN YET
ANOTHER SLIGHT TO CHANCE OF RAIN SHOWERS - OR SNOW SHOWERS WHERE/IF
THE SUB-CLOUD LAYER FULLY WET-BULBS AND THEORETICALLY "MELTS OUT" A
PROJECTED 1500-2000 FT ABOVE FREEZING BOUNDARY LAYER. THE REMAINDER
OF THE LONG TERM WILL BE DRY AND CHILLY... PARTICULARLY WITH RESPECT
TO LOWS BOTH WED AND THU MORNINGS...AS MODIFIED ARCTIC HIGH PRESSURE
DRIFTS OVERHEAD IN THE WAKE OF THE TROUGH AXIS MOVING AWAY FROM THE
NC COAST.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 650 AM FRIDAY...
VFR CONDITIONS...UNDER THE INFLUENCE OF CONTINENTAL POLAR HIGH
PRESSURE BUILDING EAST ACROSS THE VIRGINIAS THIS MORNING...WILL
PREVAIL UNTIL MIDDAY-EARLY AFTERNOON...AT WHICH TIME LIFT AND
MOISTURE WILL HAVE SUFFICIENTLY INCREASED AND CAUSED RAIN AND
ASSOCIATED MVFR CEILINGS AND VISIBILITIES TO OVERSPREAD OUR AREA
DOWNSTREAM OF A STORM SYSTEM APPROACHING FROM THE NORTHERN GULF OF
MEXICO. RAIN INTENSITY WILL FURTHER INCREASE...AND AVIATION
CONDITIONS FURTHER DETERIORATE TO LIFR-IFR...THROUGH THE AFTERNOON
AND EVENING. IN ADDITION...THE ARRIVAL OF AN EAST SOUTHEASTERLY TO
SOUTHERLY LOW LEVEL JET AT 2000 FT...ATOP MUCH LIGHTER EASTERLY
WINDS AT THE SURFACE...WILL PROMOTE A GOOD CHANCE OF LOW LEVEL WIND
SHEAR CONDITIONS AT EASTERN TERMINALS THIS EVENING. PERIODS OF RAIN
AND DRIZZLE...AND LIFR CONDITIONS...WILL CONTINUE OVERNIGHT...AS THE
LOW PRESSURE SYSTEM TRACKS JUST INLAND OF THE COAST OF THE
CAROLINAS.
OUTLOOK: RAIN WILL LINGER THROUGH MIDDAY SAT...WHILE CEILINGS AND
VISIBILITIES GRADUALLY RISE THROUGH MVFR RANGE...TO VFR BY
AFTERNOON...AS THE LOW PRESSURE SYSTEM TRACKS UP THE MIDDLE ATLANTIC
COAST AND AWAY FROM CENTRAL NC. A COUPLE OF UPPER LEVEL DISTURBANCES
WILL BRING A RENEWED CHANCE OF BRIEF SUB-VFR CONDITIONS AND RAIN
SHOWERS TO THE AREA SUN NIGHT-MON NIGHT...THE LATTER OF WHICH COULD
MIX WITH OR CHANGE TO LIGHT SNOW AS COLDER TEMPERATURES ARRIVE BY
MON EVENING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...BADGETT/BLS
SHORT TERM...BLS/MWS
LONG TERM...MWS
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
652 AM EST FRI JAN 23 2015
.SYNOPSIS...HIGH PRESSURE WILL BUILD ACROSS VA AND NC THIS MORNING.
MEANWHILE...A LOW PRESSURE SYSTEM WILL TRACK JUST INLAND OF THE
SOUTHEAST US COAST THROUGH TONIGHT...THEN OFFSHORE THE MIDDLE
ATLANTIC AND NEW ENGLAND COAST ON SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM FRIDAY...
A POSITIVELY TILTED TROUGH OVER THE SOUTHERN PLAINS WILL CONTINUE
TO MOVE EAST ACROSS THE GULF COAST STATES TODAY AND THEN BEGIN TO
LIFT ACROSS THE CAROLINAS LATER TONIGHT. CYCLOGENESIS APPEARS TO BE
UNDERWAY SOUTH OF NEW ORLEANS THIS MORNING... AND THIS LOW FORECAST
IS TO TRACK ACROSS SOUTHERN GEORGIA AND UP THE CAROLINA COASTAL AREA
TONIGHT.
A LARGE AREA RAIN IS CURRENTLY SPREADING ACROSS ALABAMA AND
GEORGIA...WITH A FEW RADAR ECHOES AND TRACE REPORTS AS FAR EAST AS
AIKEN GEORGIA...BUT THE LEADING EDGE STILLS APPEARS TO BE DWINDLING
AS IT ENCOUNTERS THE DRIER AIR ASSOCIATED WITH A 1030MB SURFACE HIGH
CENTERED OVER SOUTHEAST VIRGINIA. THE HRRR HAS A PRETTY GOOD HANDLE
ON THIS AND SUGGESTS MEASURABLE PRECIP MAY REACH THE SOUTHERN
PIEDMONT BY 15Z. THE WETBULB FREEZING LINE IS CURRENTLY NEAR
HIGHWAY 64 AND SHOULDN`T MOVE MUCH MORE TO THE SOUTH AS MID CLOUDS
CONTINUE TO POUR IN FROM THE WEST AND TEMPS STABILIZE. RAP
SOUNDINGS SHOW JUST ENOUGH WARMING PRIOR TO THE ARRIVAL OF PRECIP TO
KEEP ALL PRECIP LIQUID AT ONSET.
ISENTROPIC LIFT REALLY INCREASES BY 18Z AND EXPECT RAIN TO BE
WIDESPREAD ACROSS THE ENTIRE AREA AFTER 21Z....WITH THE HEAVIEST
RAINFALL OCCURRING BETWEEN 00Z AND 06Z AS A 50KT LOW LEVEL JET
SURGES ACROSS CENTRAL AND EASTERN NC. THERE ARE STILL SOME
DIFFERENCE IN THE TRACK OF THE SURFACE LOW...THE ECMWF A GOOD 50 TO
75 MILES FURTHER INLAND THAN THE GFS. PREFERENCE IS FOR THE MORE
EASTERN TRACK OF THE GFS AND NAM GIVEN THAT A STRONG CAD AIRMASS
WILL DEVELOP IN RESPONSE TO THE RAIN THIS AFTERNOON. THE WEDGE FRONT
WILL LIKELY SHIFT INLAND AS THE LOW APPROACHES BUT THE TRUE WARM
SECTOR SHOULD REMAIN CONFINED TO THE COAST WHERE ANY SEVERE THREAT
WOULD ALSO REMAIN.
MODEL QPF IS RATHER HIGH TONIGHT...WITH AS MUCH AS ONE INCH IN THE
WEST AND NEAR 2 INCHES EAST OF I-95...AND THIS SEEMS VERY REASONABLE
GIVEN PW INCREASING TO AS MUCH AS 200 PERCENT OF NORMAL AND A
PLETHORA OF 1 TO 2 INCH TOTALS ALREADY REPORTED UPSTREAM ACROSS
LOUISIANA AND MISSISSIPPI. CONTEMPLATED A FLOOD WATCH GIVEN RECENT
RAINFALL EVENTS AND SOIL MOISTURE...BUT WITHOUT CONVECTION THE
FLOODING MAY MAY ISOLATED TO SOME OF THE SMALL CREEKS AND STREAMS
THAT ARE ALREADY RUNNING HIGHER THAN NORMAL. SOME MINOR RIVER
FLOODING IS ALSO POSSIBLE ON THE NEUSE AND TAR RIVERS.
TEMPS WILL RISE A LITTLE TODAY...MORE SO IN THE EAST...BUT AS PRECIP
MOVES IN THEY WILL LEVEL OFF OR EVEN DROP A BIT...WITH HIGHS INLY
REACHING THE MID 30S NORTHWEST TO MID 40S SOUTHEAST. TEMPS WON`T
CHANGE MUCH OVERNIGHT...DROPPING MAYBE 2 TO 3 DEGREES.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...
MODELS DEPICT A BRIEF PERIOD OF MID-LEVEL DRYING AS A DRY SLOT
SURGES ACROSS THE AREA LATE TONIGHT...BUT THE ARRIVAL OF THE UPPER
TROUGH AND STRONGER DCVA SHOULD CAUSE PRECIP TO REDEVELOP OR
REINTENSIFY EARLY SATURDAY...MAINLY ACROSS THE EASTERN HALF OF THE
AREA. RAINFALL TOTALS MAY NOT BE AS HIGH WITH THE SURFACE LOW
HAVING MOVED OFF TO THE NORTHEAST...BUT MODELS SHOW ANOTHER HALF
INCH POSSIBLE PRIOR TO 15Z. PRECIP WILL THEN END FOR MUCH OF THE
AREA AS MORE PRONOUNCED DRYING ALOFT DEVELOPS. HOWEVER... A
DEFORMATION BAND EXPECTED TO DEVELOP OVER THE TENNESSEE VALLEY WILL
PIVOT ACROSS AT LEAST THE NORTHERN HALF OF THE AREA AROUND MIDDAY.
RAPID MID-LEVEL COOLING AND RESATURATION OF THE ICE-NUCLEATION ZONE
SUGGESTS RAIN COULD MIX WITH OR CHANGE OVER TO SNOW WITHIN THIS
BAND...BUT FORECAST SOUNDINGS HAVE THE LOWEST 2000 FT OF THE
BOUNDARY LAYER ABOVE FREEZING AND THIS MAY BE TOO MUCH MELTING TO
OVERCOME. WILL BE INTERESTING TO SEE HOW THIS UNFOLDS...THOUGH NO
IMPACTS WOULD BE EXPECTED.
THE BAND SHOULD DEPART THE NORTHEAST CWA BY 18Z TO 21Z...WITH CLEAR
SKIES BY 00Z TO 03Z. COLD ADVECTION WILL BE RELATIVELY STRONG
SATURDAY EVENING...RESULTING WIND GUSTS OF 20-25MPH FOR THE FIRST
HALF OF THE NIGHT. LOWS WILL DROP INTO THE LOW TO MID 30S. -BLS
SUN AND SUN NIGHT: A STRONG PACIFIC JET WILL ROUND A WESTERN CONUS
RIDGE AND CAUSE AN ASSOCIATED NORTHERN STREAM SHORTWAVE TROUGH TO
AMPLIFY SHARPLY FROM THE NORTHERN PLAINS TO THE CAROLINAS AND VA
THROUGH SUN NIGHT. A CLIPPER SURFACE LOW WILL ACCOMPANY THE
SHORTWAVE TROUGH AND CROSS THE UPPER MIDWEST AND OH VALLEY SUN AND
THE CENTRAL APPALACHIANS AND MIDDLE ATLANTIC STATES SUN NIGHT. WSW
LOW LEVEL FLOW AHEAD OF THE CLIPPER LOW...AND IN BRIEF SHORTWAVE
RIDGING BETWEEN THIS SHORTWAVE TROUGH AND AN INTENSE CYCLONE
APPROACHING NOVA SCOTIA (OUR FRI-SAT WEATHER MAKER)...WILL RESULT IN
A MOSTLY SUNNY AND MILD DAY IN THE 50S TO END THE WEEKEND.
THE PASSAGE OF THE SHORTWAVE TROUGH AND ASSOCIATED COLD POOL ALOFT
CHARACTERIZED BY H5 TEMPERATURES AROUND MINUS 30 - AND POCKET OF MID
LEVEL LAPSE RATES AROUND 7 C/KM - WILL CAUSE AN AREA OF SHOWERS TO
PIVOT EAST ACROSS CENTRAL NC OVERNIGHT. ALL LIQUID IS ANTICIPATED
OWING TO A 1500-3000 FT DEEP ABOVE FREEZING BOUNDARY LAYER...LOWEST
AND COLDEST ONCE THE SHOWERS ARE MOVING OUT. LOWS...AND WITH
CLEARING SPREADING INTO THE PIEDMONT BY DAYBREAK...WITHIN A FEW
DEGREES EITHER SIDE OF 35. -MWS
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 345 AM FRIDAY...
JUST AS QUICKLY AS THE CLOUDINESS AND SHOWERS ASSOCIATED WITH THE
"ALBERTA CLIPPER"/NORTHERN STREAM SHORTWAVE WAVE MOVE OUT...
ADDITIONAL SHEAR VORTICITY IN FAST NW FLOW ALOFT WILL AMPLIFY INTO
THE TROUGH BASE...TO NEAR AND JUST OFFSHORE THE COAST OF THE
CAROLINAS...THROUGH WED MORNING. TYPICAL MEDIUM RANGE TIMING AND
AMPLITUDE DISTANCES BECOME MAGNIFIED DURING THIS TIME...WITH THE 00Z
ECMWF REPRESENTING THE SOUTHERNMOST - AND CONSEQUENTLY RELATIVELY
WETTEST FOR CENTRAL NC - SOLUTIONS FOR THE PERIOD MON-TUE. BASED ON
A PREFERRED SLIGHTLY LESS AMPLIFIED/MORE NORTHWARD CONSENSUS OF
MODEL CLUSTERING REPRESENTED WELL BY THE 00Z GFS...THE RELATIVE
HIGHEST PROBABILITY OF PRECIPITATION (IN THE CHANCE RANGE) SHOULD BE
CENTERED TOWARD THE NORTHEAST PIEDMONT WITH THE ARRIVAL OF THE LEAD
SHEAR VORTICITY AND POSSIBLE INTERACTION WITH A LOW LEVEL MOIST AXIS
OVER EASTERN NC THROUGH MON NIGHT. ANY PRECIPITATION THAT WERE TO
FALL AFTER DARK MON...AFTER TEMPERATURES PEAK IN THE UPPER 40S TO
LOWER 50S...WOULD BE IN THE FORM OF LIGHT SNOW OWING TO STRONG DEEP
LAYER COOLING MON NIGHT - A CASE OF "THE COLD AIR CHASING THE
MOISTURE".
TRAILING SHEAR VORTICITY WILL CARVE THE TROUGH OFF THE COAST OF THE
CAROLINAS TUE-TUE NIGHT. ASSOCIATED RE-STEEPENING OF THE LAPSE RATES
ALOFT...AND LIFT/MOISTENING OF THE COLUMN...WILL RESULT IN YET
ANOTHER SLIGHT TO CHANCE OF RAIN SHOWERS - OR SNOW SHOWERS WHERE/IF
THE SUB-CLOUD LAYER FULLY WET-BULBS AND THEORETICALLY "MELTS OUT" A
PROJECTED 1500-2000 FT ABOVE FREEZING BOUNDARY LAYER. THE REMAINDER
OF THE LONG TERM WILL BE DRY AND CHILLY... PARTICULARLY WITH RESPECT
TO LOWS BOTH WED AND THU MORNINGS...AS MODIFIED ARCTIC HIGH PRESSURE
DRIFTS OVERHEAD IN THE WAKE OF THE TROUGH AXIS MOVING AWAY FROM THE
NC COAST.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 650 AM FRIDAY...
VFR CONDITIONS...UNDER THE INFLUENCE OF CONTINENTAL POLAR HIGH
PRESSURE BUILDING EAST ACROSS THE VIRGINIAS THIS MORNING...WILL
PREVAIL UNTIL MIDDAY-EARLY AFTERNOON...AT WHICH TIME LIFT AND
MOISTURE WILL HAVE SUFFICIENTLY INCREASED AND CAUSED RAIN AND
ASSOCIATED MVFR CEILINGS AND VISIBILITIES TO OVERSPREAD OUR AREA
DOWNSTREAM OF A STORM SYSTEM APPROACHING FROM THE NORTHERN GULF OF
MEXICO. RAIN INTENSITY WILL FURTHER INCREASE...AND AVIATION
CONDITIONS FURTHER DETERIORATE TO LIFR-IFR...THROUGH THE AFTERNOON
AND EVENING. IN ADDITION...THE ARRIVAL OF AN EAST SOUTHEASTERLY TO
SOUTHERLY LOW LEVEL JET AT 2000 FT...ATOP MUCH LIGHTER EASTERLY
WINDS AT THE SURFACE...WILL PROMOTE A GOOD CHANCE OF LOW LEVEL WIND
SHEAR CONDITIONS AT EASTERN TERMINALS THIS EVENING. PERIODS OF RAIN
AND DRIZZLE...AND LIFR CONDITIONS...WILL CONTINUE OVERNIGHT...AS THE
LOW PRESSURE SYSTEM TRACKS JUST INLAND OF THE COAST OF THE
CAROLINAS.
OUTLOOK: RAIN WILL LINGER THROUGH MIDDAY SAT...WHILE CEILINGS AND
VISIBILITIES GRADUALLY RISE THROUGH MVFR RANGE...TO VFR BY
AFTERNOON...AS THE LOW PRESSURE SYSTEM TRACKS UP THE MIDDLE ATLANTIC
COAST AND AWAY FROM CENTRAL NC. A COUPLE OF UPPER LEVEL DISTURBANCES
WILL BRING A RENEWED CHANCE OF BRIEF SUB-VFR CONDITIONS AND RAIN
SHOWERS TO THE AREA SUN NIGHT-MON NIGHT...THE LATTER OF WHICH COULD
MIX WITH OR CHANGE TO LIGHT SNOW AS COLDER TEMPERATURES ARRIVE BY
MON EVENING.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...BLS
SHORT TERM...BLS/MWS
LONG TERM...MWS
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
852 AM EST FRI JAN 23 2015
.SYNOPSIS...
STRENGTHENING LOW PRESSURE ACROSS SOUTHEAST TODAY AND OFF NEW
ENGLAND COAST SATURDAY. CLIPPER LATE SUNDAY/SUNDAY NIGHT. TURNING
COLDER MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
850 AM UPDATE...TWEAKED POPS A BIT...TO INCLUDE A CHANCE ACROSS
THE SOUTH A COUPLE OF HOURS QUICKER BASED ON RADAR TRENDS.
OTHERWISE...NO SIGNIFICANT CHANGES NEEDED AT THIS POINT.
PREVIOUS DISCUSSION BELOW...
ALL ON EYES ON SURFACE LOW TRAVERSING THRU THE SE STATES
TODAY...FOLLOWED BY AN UPPER TROF AXIS CROSSING THE REGION
OVERNIGHT. THERE ARE A NUMBER OF MITIGATING FACTORS THAT WILL KEEP
THE WINTRY EFFECTS FROM THIS MINIMAL. A LACK OF A SURFACE HIGH TO
THE N...MARGINAL COLD AIR ALOFT...AND A PESKY INVERTED SURFACE TROF
OVER THE AREA...ALL POINT TO MORE OF A NUISANCE EVENT.
AS FOR THE NITTY GRITTY DETAILS...
SPED UP POPS A BIT FROM PREVIOUS FORECAST...PRIMARILY USING THE HRRR
TIMING. A RELATIVELY DEEP DOWNSLOPING SSE TO SE FLOW INTO MIDDAY MAY
GIVE TEMPS A SPIKE. HOWEVER...NONE OF THE MODELS ARE SHOWING THIS
EXCEPT HRRR AND RUC. SO KEPT HIGHS IN CHECK BUT STILL A FEW DEGREES
ABOVE GUIDANCE FROM ALONG US119 AND I79 CORRIDOR OVER TO W SLOPES.
THERMAL PROFILES FROM VARIOUS HI RES MODELS INDICATED PRECIP
STARTING AS RAIN OUTSIDE OF THE MOUNTAINS. PRECIP SHOULD START OUT
AS SNOW OR A MIX OF SNOW AND SLEET IN THE MOUNTAINS...WHERE A FEW
INCHES WERE CODED UP FOR LATE THIS AFTERNOON.
THIS EVENING...THE STEADY PRECIP WILL HAVE SHIFTED INTO SE OH AND N
WV WITH SCT COVERAGE IN THE MID LEVEL DRY PUNCH ELSEWHERE. THE
SURFACE LOW WILL BE MAKING A RUN OFF THE TIDEWATER REGION WITH THE
INVERTED SURFACE TROF LINGERING OVER THE AREA. MODEL SOUNDINGS SHOW
A WARM LAYER ALOFT ACROSS THE MOUNTAINS...DEEP ENOUGH FOR THE PRECIP
TO CHANGE TO FREEZING RAIN ACROSS THE ELEVATION ABOVE 3.5KFT...WITH
SOME SLEET EXPECTED OVER THE TYGART AND ESPECIALLY THE GREENBRIER
VALLEY. IT IS EVEN POSSIBLE SNOWSHOE CHANGES TO LIGHT RAIN FOR A
TIME. MEANWHILE...THE CHANGEOVER TO WET SNOW WILL BE OCCURRING
ACROSS NE KY AND SE OH AS THE UPPER TROF AXIS CLOSES IN WITH COOLING
ALOFT. THERE CONTINUES TO BE A DEFORMATION BAND OF SORTS SHOWING UP
ON THE MODELS AS THE UPPER TROF CROSSES. HAVE ORIENTED THE POPS TO
REFLECT THIS THINKING...SLOWLY TRACKING IT E FROM SE OH/NE KY INTO C
WV BY PREDAWN HRS. THIS SHOULD COINCIDE WITH THE CHANGEOVER TO WET
SNOW. HAVE ALLOWED AROUND AN INCH TO FALL ACROSS SE OH/NE KY/W WV
WITH A COATING FURTHER E AS THE OVERALL BAND BEGINS TO WEAKEN.
ACROSS THE MOUNTAINS...PRECIP WILL CHANGE BACK TO SNOW AFTER
MIDNIGHT BUT PRECIP SHOULD BE SPOTTY UNTIL THE UPPER TROF AXIS AND
DEFORMATION BAND MOVES IN TOWARD MORNING.
AFTER COLLABORATION WITH SURROUNDING OFFICES...HAVE HOISTED A WINTER
WEATHER ADVISORY FOR RANDOLPH AND POCAHONTAS. DESPITE NOT REACHING
CRITERIA SNOW WISE...THERE IS EXPECTED TO BE SOME FREEZING RAIN IN
THE HIGHER ELEVATIONS WHICH MAY ACCRUE TO AROUND A TENTH OF AN
INCH. STARTED IT THIS AFTERNOON TO HIT THE INITIAL LIGHT
ACCUMULATION OF SNOW WITH THE ICE THREAT FROM 00 TO 06Z. ENDED IT AT
15Z WHEN THE UPPER TROF IS EXPECTED TO HAVE MOVED THRU.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
MODELS SHOW SYSTEM PULLING OUT EARLY SATURDAY. SOME MARGINAL UPSLOPE
THEN APPEARS POSSIBLE SATURDAY NIGHT AS NORTHWEST WINDS PULL IN SOME
COOLER AIR. 850 MB TEMPERATURES ARE MARGINAL FOR AUTO CONVECTION IN
THE LOWER LEVELS...SO WILL KEEP POPS IN THE CHANCE CATEGORY.
MODELS ARE A BIT FASTER WITH A CLIPPER MOVING THROUGH LATE
SUNDAY/SUNDAY EVENING. BOTH NAM AND GFS ARE SHOWING LOTS OF LIFT
WELL SOUTH OF THE LOW TRACK...BUT CLIPPERS USUALLY STRUGGLE TO
PRODUCE PRECIPITATION SOUTH OF THE LOW. THEREFORE...WILL SHOW A
NORTH SOUTH GRADIENT OF POPS.
COLDER AIR BEHIND THE CLIPPER ON MONDAY IS COLD ENOUGH FOR AUTO
CONVECTIVE CONDITIONS IN THE LOWER LEVELS...SO WILL KEEP HIGH POPS
OF SNOW.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
THE TREND THAT WE MENTIONED YESTERDAY REMAINS...THE CLIPPER COMING
EAST THROUGH THE MIDWEST INTO THE UPPER OHIO VALLEY...AT A HIGHER
LATITUDE REMAINS. AS A RESULT...WAS A BIT SLOWER BRINGING IN THE
COLDER AIR LATE SUNDAY NIGHT INTO MONDAY. POPS INCREASE NW TO SE
DURING SUNDAY NIGHT IN THE WAKE OF THE CLIPPER PASSING OUR LONGITUDE.
WE WILL BE CONSISTENT WITH POPS IN THE LIKELY CATEGORY MONDAY INTO
MONDAY EVENING BEFORE WANING FROM WEST TO EAST. AS MOISTURE
THINS...850 TEMPS BECOME COLDER...SO HELD ONTO SOME FLAKES EVEN
INTO TUESDAY EAST OF THE OHIO RIVER.
STILL DRY ON WEDNESDAY. WARMING 850 TEMPS WEDNESDAY NIGHT INTO
THURSDAY. NEXT WESTERN FRONT LONG ABOUT THURSDAY AFTERNOON.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
12Z FRIDAY THRU 12Z SATURDAY...
A LOW PRESSURE SYSTEM WILL APPROACH FROM THE SOUTH SOUTHWEST TODAY.
CIGS WILL LOWER AS PRECIP MOVES IN FROM THE SW THIS
AFTERNOON...FIRST ACROSS SW VA AND SE WV AFFECTING KBKW BY 18Z
WITH MVFR. PRECIPITATION OVERSPREADS THE REGION TOWARD EVENING
WITH MOST OF REMAINING TERMINALS EXPERIENCING MVFR CIGS IN PRECIP
BY 21Z. MVFR VSBY WILL LAG BEHIND A FEW HRS. EXPECT BULK OF PRECIP
THRU 00Z TO BE LIQUID...SAVE FOR A HR OR TWO OF A MIX FOR KBKW AT
ONSET.
CIGS WILL LOWER INTO IFR LATE THIS AFTERNOON AND EARLY EVENING WITH A
GRADUAL CHANGEOVER TO WET SNOW OVERNIGHT. VSBY WILL FOLLOW SUITE WITH
LOCALIZED VLIFR VSBY. IN THE HIGH TERRAIN A VARIETY OF PRECIP
TYPES CAN BE EXPECTED DEPENDING ON ELEVATION.
LOW LEVEL FLOW WILL BRIEFLY STRENGTHEN OUT OF SSE THIS
MORNING...PROVIDING FOR SOME 15 TO 20 KT GUSTS AT KBKW. OTHERWISE 5
TO 10 KT WINDS OUT OF NE FOR W TERMINALS AND E FOR THE MOUNTAIN
TERMINALS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SATURDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIO: TIMING LOWERING OF CIGS INTO MVFR OR WORSE
ALONG WITH VSBY MAY VARY A FEW HRS THIS AFTERNOON/EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EST 1HRLY 09 10 11 12 13 14 15 16 17 18 19 20
CRW CONSISTENCY H H H H H M M M M M M M
HTS CONSISTENCY H H H H H M M M M M H H
BKW CONSISTENCY H H M L H H H H H H H H
EKN CONSISTENCY H H H H H M H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H M H H M H M
AFTER 12Z SATURDAY...
IFR POSSIBLE EARLY SATURDAY MORNING IN SNOW. IFR POSSIBLE IN SNOW IN
THE HIGHER ELEVATIONS OF THE MOUNTAINS SUNDAY/SUNDAY NIGHT. IFR
POSSIBLE AREA WIDE IN SNOW SHOWERS MONDAY/MONDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 10 AM EST
SATURDAY FOR WVZ046-047.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/RPY/30
NEAR TERM...SL/30
SHORT TERM...RPY
LONG TERM...KTB
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
600 AM EST FRI JAN 23 2015
.SYNOPSIS...
STRENGTHENING LOW PRESSURE ACROSS SOUTHEAST TODAY AND OFF NEW
ENGLAND COAST SATURDAY. CLIPPER LATE SUNDAY/SUNDAY NIGHT. TURNING
COLDER MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
645 AM UPDATE...
NO SIGNIFICANT CHANGES ATTM. DEFORMATION BAND TONIGHT MAY NEED TO
INITIALLY BE MOVED W A BIT IF HI RES MODEL TRENDS CONTINUE.
PREVIOUS DISCUSSION BELOW...
ALL ON EYES ON SURFACE LOW TRAVERSING THRU THE SE STATES
TODAY...FOLLOWED BY AN UPPER TROF AXIS CROSSING THE REGION
OVERNIGHT. THERE ARE A NUMBER OF MITIGATING FACTORS THAT WILL KEEP
THE WINTRY EFFECTS FROM THIS MINIMAL. A LACK OF A SURFACE HIGH TO
THE N...MARGINAL COLD AIR ALOFT...AND A PESKY INVERTED SURFACE TROF
OVER THE AREA...ALL POINT TO MORE OF A NUISANCE EVENT.
AS FOR THE NITTY GRITTY DETAILS...
SPED UP POPS A BIT FROM PREVIOUS FORECAST...PRIMARILY USING THE HRRR
TIMING. A RELATIVELY DEEP DOWNSLOPING SSE TO SE FLOW INTO MIDDAY MAY
GIVE TEMPS A SPIKE. HOWEVER...NONE OF THE MODELS ARE SHOWING THIS
EXCEPT HRRR AND RUC. SO KEPT HIGHS IN CHECK BUT STILL A FEW DEGREES
ABOVE GUIDANCE FROM ALONG US119 AND I79 CORRIDOR OVER TO W SLOPES.
THERMAL PROFILES FROM VARIOUS HI RES MODELS INDICATED PRECIP
STARTING AS RAIN OUTSIDE OF THE MOUNTAINS. PRECIP SHOULD START OUT
AS SNOW OR A MIX OF SNOW AND SLEET IN THE MOUNTAINS...WHERE A FEW
INCHES WERE CODED UP FOR LATE THIS AFTERNOON.
THIS EVENING...THE STEADY PRECIP WILL HAVE SHIFTED INTO SE OH AND N
WV WITH SCT COVERAGE IN THE MID LEVEL DRY PUNCH ELSEWHERE. THE
SURFACE LOW WILL BE MAKING A RUN OFF THE TIDEWATER REGION WITH THE
INVERTED SURFACE TROF LINGERING OVER THE AREA. MODEL SOUNDINGS SHOW
A WARM LAYER ALOFT ACROSS THE MOUNTAINS...DEEP ENOUGH FOR THE PRECIP
TO CHANGE TO FREEZING RAIN ACROSS THE ELEVATION ABOVE 3.5KFT...WITH
SOME SLEET EXPECTED OVER THE TYGART AND ESPECIALLY THE GREENBRIER
VALLEY. IT IS EVEN POSSIBLE SNOWSHOE CHANGES TO LIGHT RAIN FOR A
TIME. MEANWHILE...THE CHANGEOVER TO WET SNOW WILL BE OCCURRING
ACROSS NE KY AND SE OH AS THE UPPER TROF AXIS CLOSES IN WITH COOLING
ALOFT. THERE CONTINUES TO BE A DEFORMATION BAND OF SORTS SHOWING UP
ON THE MODELS AS THE UPPER TROF CROSSES. HAVE ORIENTED THE POPS TO
REFLECT THIS THINKING...SLOWLY TRACKING IT E FROM SE OH/NE KY INTO C
WV BY PREDAWN HRS. THIS SHOULD COINCIDE WITH THE CHANGEOVER TO WET
SNOW. HAVE ALLOWED AROUND AN INCH TO FALL ACROSS SE OH/NE KY/W WV
WITH A COATING FURTHER E AS THE OVERALL BAND BEGINS TO WEAKEN.
ACROSS THE MOUNTAINS...PRECIP WILL CHANGE BACK TO SNOW AFTER
MIDNIGHT BUT PRECIP SHOULD BE SPOTTY UNTIL THE UPPER TROF AXIS AND
DEFORMATION BAND MOVES IN TOWARD MORNING.
AFTER COLLABORATION WITH SURROUNDING OFFICES...HAVE HOISTED A WINTER
WEATHER ADVISORY FOR RANDOLPH AND POCAHONTAS. DESPITE NOT REACHING
CRITERIA SNOW WISE...THERE IS EXPECTED TO BE SOME FREEZING RAIN IN
THE HIGHER ELEVATIONS WHICH MAY ACCRUE TO AROUND A TENTH OF AN
INCH. STARTED IT THIS AFTERNOON TO HIT THE INITIAL LIGHT
ACCUMULATION OF SNOW WITH THE ICE THREAT FROM 00 TO 06Z. ENDED IT AT
15Z WHEN THE UPPER TROF IS EXPECTED TO HAVE MOVED THRU.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
MODELS SHOW SYSTEM PULLING OUT EARLY SATURDAY. SOME MARGINAL UPSLOPE
THEN APPEARS POSSIBLE SATURDAY NIGHT AS NORTHWEST WINDS PULL IN SOME
COOLER AIR. 850 MB TEMPERATURES ARE MARGINAL FOR AUTO CONVECTION IN
THE LOWER LEVELS...SO WILL KEEP POPS IN THE CHANCE CATEGORY.
MODELS ARE A BIT FASTER WITH A CLIPPER MOVING THROUGH LATE
SUNDAY/SUNDAY EVENING. BOTH NAM AND GFS ARE SHOWING LOTS OF LIFT
WELL SOUTH OF THE LOW TRACK...BUT CLIPPERS USUALLY STRUGGLE TO
PRODUCE PRECIPITATION SOUTH OF THE LOW. THEREFORE...WILL SHOW A
NORTH SOUTH GRADIENT OF POPS.
COLDER AIR BEHIND THE CLIPPER ON MONDAY IS COLD ENOUGH FOR AUTO
CONVECTIVE CONDITIONS IN THE LOWER LEVELS...SO WILL KEEP HIGH POPS
OF SNOW.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
THE TREND THAT WE MENTIONED YESTERDAY REMAINS...THE CLIPPER COMING
EAST THROUGH THE MIDWEST INTO THE UPPER OHIO VALLEY...AT A HIGHER
LATITUDE REMAINS. AS A RESULT...WAS A BIT SLOWER BRINGING IN THE
COLDER AIR LATE SUNDAY NIGHT INTO MONDAY. POPS INCREASE NW TO SE
DURING SUNDAY NIGHT IN THE WAKE OF THE CLIPPER PASSING OUR LONGITUDE.
WE WILL BE CONSISTENT WITH POPS IN THE LIKELY CATEGORY MONDAY INTO
MONDAY EVENING BEFORE WANING FROM WEST TO EAST. AS MOISTURE
THINS...850 TEMPS BECOME COLDER...SO HELD ONTO SOME FLAKES EVEN
INTO TUESDAY EAST OF THE OHIO RIVER.
STILL DRY ON WEDNESDAY. WARMING 850 TEMPS WEDNESDAY NIGHT INTO
THURSDAY. NEXT WESTERN FRONT LONG ABOUT THURSDAY AFTERNOON.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
12Z FRIDAY THRU 12Z SATURDAY...
A LOW PRESSURE SYSTEM WILL APPROACH FROM THE SOUTH SOUTHWEST TODAY.
CIGS WILL LOWER AS PRECIP MOVES IN FROM THE SW THIS
AFTERNOON...FIRST ACROSS SW VA AND SE WV AFFECTING KBKW BY 18Z
WITH MVFR. PRECIPITATION OVERSPREADS THE REGION TOWARD EVENING
WITH MOST OF REMAINING TERMINALS EXPERIENCING MVFR CIGS IN PRECIP
BY 21Z. MVFR VSBY WILL LAG BEHIND A FEW HRS. EXPECT BULK OF PRECIP
THRU 00Z TO BE LIQUID...SAVE FOR A HR OR TWO OF A MIX FOR KBKW AT
ONSET.
CIGS WILL LOWER INTO IFR LATE THIS AFTERNOON AND EARLY EVENING WITH A
GRADUAL CHANGEOVER TO WET SNOW OVERNIGHT. VSBY WILL FOLLOW SUITE WITH
LOCALIZED VLIFR VSBY. IN THE HIGH TERRAIN A VARIETY OF PRECIP
TYPES CAN BE EXPECTED DEPENDING ON ELEVATION.
LOW LEVEL FLOW WILL BRIEFLY STRENGTHEN OUT OF SSE THIS
MORNING...PROVIDING FOR SOME 15 TO 20 KT GUSTS AT KBKW. OTHERWISE 5
TO 10 KT WINDS OUT OF NE FOR W TERMINALS AND E FOR THE MOUNTAIN
TERMINALS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SATURDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIO: TIMING LOWERING OF CIGS INTO MVFR OR WORSE
ALONG WITH VSBY MAY VARY A FEW HRS THIS AFTERNOON/EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY H H H H H H H H M M H M
HTS CONSISTENCY H H H H H H H H H M H M
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H M H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z SATURDAY...
IFR POSSIBLE EARLY SATURDAY MORNING IN SNOW. IFR POSSIBLE IN SNOW IN
THE HIGHER ELEVATIONS OF THE MOUNTAINS SUNDAY/SUNDAY NIGHT. IFR
POSSIBLE AREA WIDE IN SNOW SHOWERS MONDAY/MONDAY NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY FROM 2 PM THIS AFTERNOON TO 10 AM EST
SATURDAY FOR WVZ046-047.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...KTB
AVIATION...30
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
540 AM CST FRI JAN 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST FRI JAN 23 2015
THE MAIN FOCUS FOR THE EARLY PART OF THE FORECAST IS ON THE
POTENTIAL FOR FREEZING RAIN AND SLEET THIS MORNING.
CURRENTLY...A NORTHEAST TO SOUTHWEST ORIENTED MID LEVEL SHORT WAVE
TROUGH IS DROPPING SOUTH INTO NORTHERN MINNESOTA WITH A BAND OF
LIGHT PRECIPITATION OUT AHEAD OF IT. AT THE SURFACE/LOW LEVELS...A
NORTH TO SOUTH ORIENTED WARM FRONT IS ADVANCING SOUTHEASTWARD AS
WELL ACROSS MINNESOTA WITH THIS WARM LAYER CAUSING SOME
PRECIPITATION TYPE ISSUES IN NORTHERN MINNESOTA. EVEN THOUGH
SURFACE TEMPERATURES HAVE CLIMBED ABOVE FREEZING...ROAD
TEMPERATURES ARE STILL BELOW FREEZING AND IS CAUSING SOME ICY
CONDITIONS. SIMILAR CONDITIONS ARE NOTED LOCALLY WITH ROAD SENSORS
SAYING ROAD TEMPERATURES ARE CURRENTLY IN THE UPPER 20S TO AROUND
30.
THE QUESTION LOCALLY IS WITH HOW MUCH OF THIS PRECIPITATION WILL
MAKE IT DOWN HERE AND HOW FAR SOUTHEAST WILL THE WARM LAYER MAKE
IT. 23.07Z RAP SOUNDINGS SHOW A SUBSTANTIAL DRY LAYER IN THE
LOWEST 5-6KFT OF THE PROFILE IN MOST SITES FROM POINTS SOUTH OF
SOUTHEAST MINNESOTA GOING EAST THROUGH CENTRAL WISCONSIN. FURTHER
NORTH...HOWEVER...TOWARD NORTH CENTRAL WISCONSIN THE POTENTIAL IS
THERE FOR DEEPER SATURATION AND A HIGHER CHANCE FOR PRECIPITATION.
THE WARM LAYER APPEARS TO CREEP UP TOWARD 1 TO 3C ABOVE
FREEZING...SO THERE WILL LIKELY BE SOME MELTING OF ANY ICE/SNOW
THAT TRIES TO FALL THROUGH THE COLUMN. THE WARMER PART OF THE WARM
NOSE APPEARS TO DROP DOWN FROM FAR NORTHWEST WISCONSIN DOWN TO
SOUTHEAST MINNESOTA/NORTH CENTRAL IOWA THIS MORNING...SO THE MAIN
PRECIPITATION TYPE THERE WOULD BE RAIN...IF IT PRECIPITATES. SAY
THAT IT DOES OCCUR...THE QUESTION BECOMES WHAT ROAD TEMPERATURES
WILL DO THROUGH THE MORNING.
OVERALL CONFIDENCE IS HIGHEST IN TAYLOR COUNTY THAT SOME ISSUES
WILL OCCUR WITH FREEZING RAIN/SLEET...SO WILL ADD THEM TO THE
ADVISORY. SHOULD THE PRECIPITATION MAKE IT FURTHER SOUTH...THEN A
SOUTHWARD EXPANSION TO THE ADVISORY MAY BE NEEDED...BUT CONFIDENCE
IS NOT HIGH ENOUGH AT THIS POINT TO DO THAT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 340 AM CST FRI JAN 23 2015
THE MAIN FOCUS IN THE EXTENDED PERIOD IS WITH THE SNOW AMOUNTS ON
SATURDAY NIGHT INTO SUNDAY AS A LOW PRESSURE SYSTEM DROPS DOWN
FROM SOUTHERN CANADA. CONFIDENCE IS HIGH THAT THIS SYSTEM WILL BE
MOVING THROUGH IN THE SATURDAY NIGHT/SUNDAY TIME FRAME...BUT
CONFIDENCE IS RATHER LOW WITH THE TRACK OF THE SYSTEM. THE 23.00Z
ECMWF IS THE FURTHEST SOUTH WITH THE LEAST AMOUNT OF SNOW...THE
23.00Z NAM IS THE SLOWEST AND HAS THE NARROWEST BAND MOVING
THROUGH WEST CENTRAL WISCONSIN AND THE 23.00Z GFS IS SOMEWHERE IN
BETWEEN THESE TWO WITH THE MOST WIDESPREAD AND HEAVIEST SNOW. AT
THIS POINT...CAN ONLY TAKE THE MIDDLE OF THE ROAD WHICH ENDS UP
BEING CLOSE TO THE GFS PATH WITH LESS QPF. STILL...WITH SNOW
RATIOS OF AROUND 13:1 AND QPF OF AROUND A QUARTER OF AN
INCH...COULD SEE SOME 2 TO 4 INCH SNOWS FROM THIS QUICK MOVING
SYSTEM. INCREASED THE PRECIPITATION CHANCES FOR THE EVENT SINCE
IT IS LOOKING LIKE MOST OF THE REGION WILL SEE SOME SNOW...IT IS
JUST A MATTER OF HOW MUCH.
BEYOND THIS...ONLY MADE SOME ADJUSTMENTS TO THE WEDNESDAY HIGH
TEMPERATURE FORECAST FOR WHAT APPEARS TO BE A STRONG SOUTHERLY
FLOW DAY WITH A WARM AIR MASS MOVING IN FROM THE SOUTH.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 540 AM CST FRI JAN 23 2015
INCREASING SOUTHWEST LOW LEVEL FLOW HAS FINALLY PUSHED THE MVFR
CLOUD DECK EAST AND OUT OF THE TAF SITES. GENERALLY GOOD VFR
CONDITIONS EXPECTED TODAY...WITH MODERATE SOUTHWEST WINDS OF 10-
20KTS. A COLD FRONT WILL DROP SOUTH ACROSS THE AREA LATE THIS
AFTERNOON/EARLY THIS EVENING. LOW LEVEL MOISTURE WILL ONCE AGAIN
INCREASE ACROSS THE AREA BEHIND THIS FRONT. MVFR CLOUD DECKS TO MOVE
INTO THE TAF SITES VERY LATE THIS AFTERNOON...THEN PERSIST THRU
TONIGHT. WITH DIURNAL COOLING...CLOUD HGTS EXPECTED TO DROP TO IFR
AT KRST BY MID EVENING. NORTHWEST WINDS 10-15KT ALSO SPREAD ACROSS
THE AREA BEHIND THE FRONT FOR TONIGHT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ017.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
307 PM EST FRI JAN 23 2015
.DISCUSSION...
...STORMS ACROSS THE REGION THIS EVENING INTO EARLY SAT...
...HAZARDOUS BOATING CONDITIONS WILL WORSEN INTO SAT...
CURRENTLY-TONIGHT...AFTERNOON CUMULUS DEVELOPMENT HAS BEEN
SHALLOW AND THE LATEST RAP FORECAST SOUNDINGS ONLY SHOW A LITTLE
CAPE DEVELOPING ACROSS THE FAR NORTH...SO THE CHANCE FOR CELLS
TO FORM IN THE MORE SHEARED LOW LEVEL ENVIRONMENT AHEAD OF PRE
FRONTAL SQUALL LINE LOOKS LOW. BUT THE HRRR DOES SHOW SLIGHT
COVERAGE SO WE WILL HAVE TO WATCH FOR SHOWERS OR STORMS WITH SOME
ROTATION IN THAT AREA UNTIL AROUND SUNSET.
THE LATEST HRRR BRINGS THE SQUALL LINE INTO OUR NORTHERN SECTIONS
JUST AFTER 00Z AND CENTRAL SECTIONS AROUND 06Z. THIS IS A LITTLE
FASTER THAN EXTRAPOLATION BUT THIS PERIOD WILL BE WHEN WIND
PROFILES ARE STRENGTHENING DUE TO INTENSIFYING SURFACE LOW MOVING
NORTH OF THE STATE. SO SOME ACCELERATION IS EXPECTED. SEE NO
REASON TO DIFFER WITH THE MOS CATEGORICAL POPS ACROSS THE NORTH.
THE TRAILING SOUTHERN END OF THE LINE WILL PROBABLY BE SLOW TO
REACH SOUTHERN SECTIONS...SO WE WILL HAVE A WIDE POP RANGE FROM
NORTH TO SOUTH (90 PERCENT TO 20 PERCENT).
THE MAIN QUESTION IS HOW VIGOROUS THE CONVECTION WILL BE TONIGHT
WITH THE PRE FRONTAL LINE. THE MODELS CONTINUE TO SHOW MEAGER CAPE
BUT WITH INCREASING WIND PROFILES THE CELLS WILL BE VERY FAST
MOVING...IN A FLOW THAT BECOMES GRADUALLY MORE UNIDIRECTIONAL.
THEREFORE EXPECT SHOWERS/STORMS WITH STRONG WIND GUSTS. LOCALIZED
DAMAGING WINDS CANNOT BE RULED OUT THOUGH.
SAT...COLD FRONT WILL BE ACROSS OUR NORTHERN SECTIONS AT SUNRISE
THEN IN SOUTH FLORIDA BY AFTERNOON. FRONTAL CONVERGENCE SHOULD BE
WEAKENING AND EXPECT A MORE NARROW BAND OF CONVECTION TO TRAVERSE
THE AREA. LOWEST POPS WILL BE ACROSS THE NORTH (40 PERCENT) AND
HIGHEST IN THE SOUTH (60 PERCENT). THIS WOULD BE IN THE MORNING
HOURS...WITH A SLIGHT CHANCE OF LINGERING SHOWERS IN THE FAR
SOUTH. COLD ADVECTION WILL KICK IN ACROSS THE NORTH EARLY AND BY
AFTERNOON IN THE SOUTH SO HAVE GONE WITH SLIGHTLY COOLER CONSENSUS
TEMPS RATHER THAN THE GFS MOS.
SAT NIGHT... BROAD CYCLONIC FLOW OVER THE SOUTHEAST UNITED STATES.
SURFACE HIGH PRESSURE CENTERED OVER SOUTHEAST TEXAS RIDGES ACROSS
THE GULF OF MEXICO AND FLORIDA. THE RESULTING NORTHWEST SURFACE AND
LOW LEVEL WIND FLOW BRINGS A MUCH COOLER AND DRIER AIR MASS INTO
CENTRAL FLORIDA. OVERNIGHT LOWS MUCH COLDER WITH MINS FORECAST NEAR
40 DEGREES TO LOWER 40S...EXCEPT MIDDLE 40S ALONG THE IMMEDIATE
TREASURE COAST. WHILE WINDS ARE FORECAST TO DIMINISH IN THE
EVENING...THEY MAY STAY NEAR 10 MPH FOR A WHILE DURING THE EVENING.
BORDERLINE WIND CHILL ADVISORY CRITERIA POSSIBLE WITH CURRENT
FORECAST LOWEST WIND CHILL READINGS IN THE UPPER 30S OVER MUCH OF
THE AREA AFTER MIDNIGHT. MUCH DRIER AIR WILL ALSO FILTER DOWN THE
PENINSULA SAT OVERNIGHT.
PREVIOUS EXTENDED DISCUSSION
SUN-THU...COOLER AND DRIER FOR THIS ENTIRE PERIOD WITH A COUPLE OF
REINFORCING FRONTS PUSHING THROUGH THE AREA. WILL CONTINUE TO LEAVE
THE EXTENDED PRECIPITATION FREE OVER LAND. HIGHS MAINLY IN THE
60S...EXCEPT NEAR 70 DEGREES ACROSS THE TREASURE COAST ON MON. LOWS
MAINLY IN THE 40S AND NEAR 50 DEGREES ALONG THE IMMEDIATE TREASURE
COAST.
&&
.AVIATION...
CEILINGS HAVE BEEN VFR THIS AFTERNOON. BUT DURING THE OVERNIGHT
AND MORNING HOURS OF SAT...THAT WILL BE CHANGING AS A PERIOD OF
MVFR/IFR WILL OCCUR WITH BAND OF SHOWERS AND STORMS MOVING ACROSS
THE TERMINALS. GUSTINESS OF SOUTHERLY WINDS SHOULD DIMINISH
TOWARDS SUNSET...BUT STRONG WIND GUSTS WILL OCCUR WITH THE
SHOWERS/STORMS. AS LOW LEVEL WINDS INCREASE DURING THE NIGHT...
EXPECT MOST ALL OF THE TERMINALS TO HAVE LOW LEVEL WIND SHEAR...AND
HAVE ALREADY PUT THAT INTO THE TAFS. POST FRONTAL WINDS ON SAT
WILL BE STRONG AND GUSTY WITH SOME SITES HAVING GUSTS NEAR 30
KNOTS.
&&
.MARINE...
TONIGHT...SOUTHERLY WINDS HAVE STEADILY INCREASED AND WITH SURFACE
LOW MOVING INTO THE FLORIDA PANHANDLE WHILE STRENGTHENING...THE
PRESSURE GRADIENT WILL CONTINUE TO INCREASE. WILL LEAVE CURRENT
HEADLINES IN PLACE WITH ADVISORY STARTING NEARSHORE/GALE WARNING
OFFSHORE THIS EVENING.
SAT-SAT NIGHT...A GALE WARNING WILL CONTINUE UNTIL 21Z/4PM SAT
AFTN OFFSHORE AND NORTH OF SEBASTIAN INLET. SMALL CRAFT ADVISORIES
REMAINING IN PLACE LIKELY EVERYWHERE ELSE THROUGH THIS TIME...AND
RESUMING AFTER 21Z FOR OFFSHORE LEGS. INITIAL SW WINDS VERY EARLY
IN THE PERIOD WILL QUICKLY VEER TO W/WNW BEHIND FRONTAL PASSAGE IN
THE MORNING. WIND SPEEDS WILL GRADUALLY DIMINISH LATE SAT WITH
SEAS SLOWER TO RESPOND. SEAS INITIALLY BUILDING TO 4-6 FT NEAR
SHORE AND 6-8 FT OFFSHORE SLOWLY SUBSIDING TO 3-5 FT NEAR SHORE
AND 5-6 FT OFFSHORE BY DAYBREAK SUN MORNING.
SAT NIGHT...NORTHWEST WINDS 15 TO 20 KNOTS DIMINISH TO AROUND 15
KNOTS LATE OVERNIGHT/SUNRISE SUNDAY MORNING. SEAS 4 TO 7 FEET
SATURDAY EVENING SUBSIDE TO 3 TO 6 FEET DAYBREAK SUNDAY. STILL
HAZARDOUS CONDITIONS WITH AT LEAST A SMALL CRAFT OPERATORS EXERCISE
CAUTION ON THE COASTAL WATERS.
PREVIOUS EXTENDED MARINE DISCUSSION
SUN-TUE...UNSETTLED EXTENDED PERIOD AHEAD. THE PRESSURE GRADIENT
CONTINUES TO EASE ON SUN BUT THIS WILL BE SHORT-LIVED AS ANOTHER
FRONT IS FORECAST TO DROP ACROSS THE AREA SUN OVERNIGHT/MON WITH
WIND SPEEDS INCREASING TO ADVISORY LEVELS ONCE AGAIN. WINDS ARE SLOW
TO DIMINISH AGAIN INTO LATE TUE. SEAS CONTINUE TO SUBSIDE INTO
SUN BUT WILL BUILD BACK UPWARD LATE OVERNIGHT SUN THRU MON BEHIND
LATEST REINFORCING FRONTAL BOUNDARY. SEAS WILL AGAIN SUBSIDE LATE
TUE/TUE OVERNIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 62 67 39 64 / 90 40 10 10
MCO 64 68 41 66 / 70 40 10 10
MLB 67 71 41 65 / 50 50 10 10
VRB 68 73 43 66 / 30 60 10 10
LEE 62 64 41 66 / 90 30 10 10
SFB 63 68 41 66 / 80 40 10 10
ORL 64 67 43 67 / 80 40 10 10
FPR 69 74 43 66 / 30 60 10 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...LAKE WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR COASTAL
VOLUSIA-INDIAN RIVER-INLAND VOLUSIA-MARTIN-NORTHERN BREVARD-
NORTHERN LAKE-OKEECHOBEE-ORANGE-OSCEOLA-SEMINOLE-SOUTHERN
BREVARD-SOUTHERN LAKE-ST. LUCIE.
AM...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 4 PM EST
SATURDAY FOR COASTAL WATERS FROM FLAGLER BEACH TO VOLUSIA
BREVARD COUNTY LINE OUT 20 NM-COASTAL WATERS FROM SEBASTIAN
INLET TO JUPITER INLET OUT 20 NM-COASTAL WATERS FROM
VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET OUT 20 NM-
WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60 NM
OFFSHORE.
SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR WATERS
FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60
NM OFFSHORE-WATERS FROM VOLUSIA BREVARD COUNTY LINE TO
SEBASTIAN INLET 20 TO 60 NM OFFSHORE.
GALE WARNING FROM 10 PM THIS EVENING TO 4 PM EST SATURDAY FOR
WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20
TO 60 NM OFFSHORE-WATERS FROM VOLUSIA BREVARD COUNTY LINE
TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE.
&&
$$
SHORT TERM...LASCODY
LONG TERM....WIMMER
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
344 PM EST FRI JAN 23 2015
.SYNOPSIS...
LOW PRESSURE WILL TRACK NORTHEAST FROM THE GULF OF MEXICO ACROSS
THE REGION TONIGHT. THE DEEPENING LOW WILL PULL AWAY TO THE
NORTHEAST SATURDAY...FOLLOWED BY WEAK HIGH PRESSURE FROM THE WEST
SUNDAY. AN AREA OF LOW PRESSURE WILL PASS WELL NORTH OF THE REGION
SUNDAY NIGHT AND EARLY MONDAY...WHICH WILL ALLOW FOR A PAIR OF
TRAILING COLD FRONTS TO SWING THROUGH SUNDAY NIGHT AND AGAIN LATE
MONDAY OR MONDAY NIGHT. HIGH PRESSURE WILL THEN BRING COLDER THAN
NORMAL TEMPERATURES INTO LATE NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
A DEEP UPPER TROUGH DIGGING INTO THE ARKLATEX REGION CONTINUES TO
SUPPORT A DEEPENING SURFACE LOW NOW MOVING OUT OF THE CENTRAL GULF
OF MEXICO INTO SOUTHERN AL. MUCH OF OUR AREA HAS REMAINED UNDER
THE INFLUENCE OF A WEAK WEDGE OF HIGH PRESSURE EXTENDING IN FROM
THE NORTHEAST. A STRONG COASTAL TROUGH HAS PERSISTED JUST OFF THE
SC/GA COAST TODAY. HOWEVER WE ARE SEEING SIGNS OF IT FINALLY
SHIFTING INLAND WITH COASTAL WINDS VEERING TO SE. AS THE 850 MB
LOW LIFTS INTO THE SOUTHERN APPALACHIANS EARLY THIS EVENING A
45-55 KT LOW-LEVEL JET SETS UP ACROSS OUR WATERS. WE EXPECT THE
COASTAL TROUGH TO RAPIDLY SHIFT INLAND BY EARLY THIS EVENING WITH
GUSTY SOUTHERLY WINDS OVERSPREADING THE AREA AS THE SURFACE LOW
MOVES INTO CENTRAL GA/SC.
EARLY THIS AFTERNOON WE HAVE SEEN A NOTICEABLE SPLIT IN THE
PRECIPITATION ASSOCIATED WITH THIS SYSTEM. THE AREA OF HEAVIEST
RAIN HAS BEEN SHIFTING ACROSS NORTHERN FL AND EXTREME SE GA TOWARD
THE ATLANTIC WATERS. A SECOND AREA OF LIGHT TO MODERATE RAIN
EXTENDS FROM OUR INLAND AREAS INTO THE SC MIDLANDS AND CENTRAL
SAVANNAH RIVER AREA PRIMARILY DUE TO ISENTROPIC ASCENT AND MOIST
OVERRUNNING. THE LATEST HRRR AND RUC-13 PICK UP ON THESE SEMI-
DISCRETE AREAS FAIRLY WELL. THE SOUTHERN BATCH WILL MOSTLY MISS
OUR AREA TO THE SOUTH WHILE THE INLAND OVERRUNNING PRECIP WILL
SHIFT FARTHER INLAND AS THE COASTAL TROUGH SHIFTS INLAND AND MOST
AREAS ENTER THE WARM SECTOR.
WE WILL HANG ONTO MODERATE UPPER FORCING THROUGH THE NIGHT AND
ATMOSPHERIC MOISTURE WILL INCREASE STEADILY THIS EVENING. HOWEVER
WE COULD SEE A LULL IN WIDESPREAD RAINFALL FOR A FEW HOURS THIS
EVENING BEFORE THE FORCING RAMPS BACK UP AS THE SURFACE LOW
APPROACHES. THE COLD FRONT WILL PUSH INTO THE AREA FROM THE WEST
LATE TONIGHT WITH A FAIRLY CONTIGUOUS BAND OF SHOWERS AND PERHAPS
AN ELEVATED THUNDERSTORM. WE MAINTAINED CATEGORICAL POPS OVERNIGHT
BUT SIGNIFICANTLY LOWERED OUR STORM-TOTAL QPF SINCE THE BRUNT OF
THE HEAVIEST RAIN LOOKS TO STAY SOUTH.
TEMPERATURES WILL RISE THIS EVENING AS THE COASTAL TROUGH SHIFTS
INLAND...THEN WE EXPECT A SLOW FALL IN TEMPS LATE AS THE COLD
FRONT PUSHES IN FROM THE WEST.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
SATURDAY...A BROAD LARGE SCALE TROUGH WILL COVER MUCH OF THE EASTERN
STATES AS A STRONG AND NEUTRALLY TILTED SHORT WAVE ALONG THE SLOPES
OF THE CENTRAL/SOUTHERN APPALACHIANS AT DAYBREAK SWEEPS QUICKLY EAST
INTO THE ATLANTIC BY 15-18Z. AT THE SURFACE WE FIND A 996 MB
EXTRA-TROPICAL LOW MOVING THROUGH THE DELMARVA AT THE START OF THE
PERIOD BEFORE IT STARTS TO BOMB OUT AS IT LIFTS RAPIDLY TO A
POSITION OFF CAPE COD IN MASSACHUSETTS BY NIGHTFALL. TRAILING FROM
THE LOW WILL BE A STRONG COLD FRONT THAT LOOKS TO BE INTO THE
ATLANTIC BY 12Z THAT TAKES THE DEEP MOISTURE AXIS WITH IT. BUT UNTIL
THE PASSAGE OF THE SHORT WAVE ALOFT WE HAVE HELD ONTO SLIGHT
CHANCE/CHANCE POPS IN GA AND CHANCE/LIKELY POPS FOR A COUPLE HOURS
IN THE MORNING...BEFORE COVERAGE DIMINISHES QUICKLY FROM SW TO NE BY
LATE MORNING AND MIDDAY. LARGE AND STEADY ISALLOBARIC PRESSURE RISES
OF AS MUCH AS 2-3MB/3 HOURS THROUGH 18Z WILL COINCIDE WITH THE BEST
COLD ADVECTION. FOR THE REST OF THE DAY COLD ADVECTION WANES...BUT
DEEP MIXING AND A TIGHT GRADIENT WILL PERSIST. THESE FACTORS SUPPORT
A BREEZY TO WINDY DAY...BUT PROBABLY NOT QUITE TO THE CRITERIA FOR A
WIND ADVISORY WHICH OCCURS WHEN WE HAVE 30 MPH SUSTAINED WINDS FOR
ONE HOUR AND/OR GUSTS OF 40 MPH OR MORE FOR ANY DURATION. CLOUD
COVER WILL ERODE FOR THE LATE MORNING/AFTERNOON FROM WEST/SW TO
EAST/NE AND ONCE INSOLATION DOES DEVELOP IT WILL SPEND MUCH OF ITS
ENERGY EVAPORATING THE PREVIOUS RAINS. THAT ALONG WITH COLD ADVECTION
WILL ACTUALLY PROVIDE THE AREA WITH A ATYPICAL DIURNAL TEMP CURVE AS
TEMPS DROP SEVERAL DEGREES IN THE MORNING BEHIND THE COLD
FRONT...THEN ONLY RISE A FEW DEGREES IN THE AFTERNOON. AS A
RESULT... MUCH OF THE DAYLIGHT HOURS WILL ONLY HAVE TEMPS IN THE
50S.
LAKE WINDS...ANALYSIS OF SOUNDINGS AND GEOSTROPHIC WINDS INDICATE
THAT WHILE WE WILL LIKELY EXPERIENCE WIND GUSTS OF 25 KT OR GREATER
OVER AND NEAR THE SHORELINE OF LAKE MOULTRIE ON SATURDAY...WINDS
WON/T MIX AS MUCH OVER THE BULK OF THE LAKE. AFTER COORDINATION WITH
WFO CAE WE HAVE CHOSEN NOT TO HOIST A LAKE WIND ADVISORY AT THIS
TIME. HOWEVER...WITH STEADY PRESSURE RISES INTO THE AFTERNOON AND
THEN A TIGHT GRADIENT...AN ADVISORY MAY YET BE REQUIRED AT A LATER
TIME.
SATURDAY NIGHT...HIGH PRESSURE FROM THE GULF WILL POKE INTO THE
FORECAST ZONES BEHIND THE LARGE AND INTENSE CYCLONIC CIRCULATION IN
WAKE OF THE STORM SYSTEM OFF NEW ENGLAND. WINDS WILL SHUT OFF
CONSIDERABLY AT SUNSET...AND ALTHOUGH MOST LOCALES WON/T GO
COMPLETELY CALM THERE IS ENOUGH RADIATIONAL COOLING UNDER CLEAR
SKIES TO SUPPORT LOWS IN THE MID AND UPPER 30S FOR ALL BUT THE
SLIGHTLY WARMER IMMEDIATE COAST.
SUNDAY...QUIET CONDITIONS WILL PREVAIL UNDER THE INFLUENCE OF
QUASI-ZONAL FLOW ALOFT AND WEAK RIDGING INITIALLY THAT GIVES WAY TO
A SLIGHTLY MORE CYCLONIC FLOW LATE IN ADVANCE OF LOW PRESSURE IN THE
OHIO VALLEY. THIS LOW WILL BE ORGANIZING IN RESPONSE TO AN
IMPRESSIVE SHORT WAVE DIGGING SE THROUGH THE OHIO...TENNESSEE AND
MISSISSIPPI VALLEYS. CONSIDERABLE SUNSHINE...DOWNSLOPE TRAJECTORIES
OFF THE APPALACHIANS AND THE DRY AIR MASS WILL ALLOW TEMPS TO
MODERATE INTO THE UPPER 50S-LOWER 60S. A RESULTANT SEA BREEZE
HOWEVER HOLDS COASTAL SC COMMUNITIES IN THE MID 50S.
SUNDAY NIGHT AND MONDAY...A VIGOROUS SHORT WAVE WILL SWING RAPIDLY
INTO THE SE SUNDAY NIGHT THEN INTO THE ATLANTIC MONDAY. CO-LOCATED
AT THE SURFACE WE FIND A CLIPPER-TYPE LOW THAT MOVES THROUGH
SOUTHERN VIRGINIA/NORTHERN NC AT NIGHT AND STARTS TO DEEPEN AS IT.
TRAILING FROM THE LOW WILL BE TWO COLD FRONTS...ONE THAT PULLS
THROUGH HERE AFTER MIDNIGHT SUNDAY NIGHT...AND THE SECOND THAT
APPROACHES BY LATE MONDAY. WITH PWATS LESS THAN 1/2 INCH...LITTLE TO
NO CONVERGENCE NOR INSTABILITY THE RISK FOR ANY SHOWERS IS REMOTE
WITH THE COLD FRONTS. WE CAN/T ENTIRELY RULE OUT SOMETHING GIVEN THE
STRONG IMPULSE ALOFT AND STEEP MID LEVEL LAPSE RATES...BUT WE HAVE
MAINTAINED THE IDEA OF A DRY FORECAST. COLD ADVECTION BEHIND THE
FIRST FRONT WILL DROP THE 850 0C ISOTHERM INTO OUR NORTHERN ZONES
LATE SUNDAY NIGHT/EARLY MONDAY. BUT THIS IS NEGATED BY PLENTY OF
INSOLATION MONDAY AND DOWNSLOPE OFF THE MOUNTAINS. THUS TEMPS WILL
ACTUALLY BE NEAR OR EVEN A TAD ABOVE NORMAL. MONDAY WILL BE ANOTHER
BREEZY DAY...MAINLY IN THE 15-20 MPH AND GUSTY RANGE.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A DRY COLD FRONT IS EXPECTED TO SHIFT THROUGH THE REGION MONDAY
NIGHT...SETTING UP COOL AND DRY CONDITIONS THROUGH AT LEAST MIDWEEK
WHILE SFC HIGH PRESSURE BUILDS OVER THE SOUTHEAST AND A LARGE MID
LVL TROUGH OF LOW PRESSURE HOLDS OVER THE EASTERN CONUS. IN
GENERAL...HIGH TEMPS WILL RANGE IN THE LOW/MID 50S TUESDAY AND
WEDNESDAY AS THE AREA REMAINS ALONG THE SOUTHERN EDGE OF TROUGH
CENTERED TO OUR NORTH. OVERNIGHT LOWS WILL RANGE IN THE LOW/MID 30S.
TEMPS SHOULD THEN SLOWLY MODIFY OVER THE SOUTHEAST LATE WEEK AS THE
MID/UPPER LVL TROUGH OF LOW PRESSURE BEGINS TO SLIDE OFF THE
ATLANTIC COAST...BUT TEMPS SHOULD REMAIN AT OR SLIGHTLY BELOW NORMAL.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
KCHS...MAINLY MVFR CONDITIONS THIS AFTERNOON...DROPPING TO IFR
CEILINGS AND OCCASIONALLY VSBYS IN STRATUS AND RAIN. THE HEAVIEST
RAIN IS EXPECTED LATE THIS AFTERNOON THROUGH MID TO LATE EVENING.
COLD FRONT WILL PUSH THROUGH LATE TONIGHT WITH IMPROVING
CONDITIONS BUT INCREASING WINDS OUT OF THE WEST.
KSAV...MAINLY IFR CEILINGS AND/OR VSBYS THROUGH TONIGHT IN RAIN
AND LOW STRATUS THOUGH PERIODS OF LIFR CEILINGS POSSIBLE AS WELL.
THUS FAR THE GUIDANCE HAS BEEN WAY TOO PESSIMISTIC ON FLIGHT
CATEGORY AT BOTH TERMINALS...THOUGH THINGS NOW APPEAR TO BE
CATCHING UP. CONDITIONS IMPROVE AFTER SUNRISE SATURDAY AS CEILINGS
LIFT TO MVFR...RAIN SHIFTS AWAY AND WINDS BECOME GUSTY OUT OF THE
WEST.
EXTENDED AVIATION OUTLOOK...VFR CONDITIONS WILL RETURN TO BOTH
TERMINALS SATURDAY AFTERNOON...THEN PERSIST THROUGH WEDNESDAY OF
NEXT WEEK. HOWEVER...WE WILL EXPERIENCE GUSTY WEST-NW WINDS SATURDAY
AFTERNOON UNTIL A LOW PRESSURE SYSTEM SHIFTS FURTHER NORTHEAST AND
AWAY FROM THE AREA AND WINDS DROP OFF BY SUNSET. GUSTY NW WINDS TO
OCCUR AGAIN MONDAY BEHIND A COLD FRONT.
&&
.MARINE...
THE COASTAL TROUGH HAS CONTINUED TO STRENGTHEN THIS AFTERNOON
THOUGH WE ARE FINALLY SEEING SIGNS OF IT SHIFTING INLAND WITH THE
APPROACHING LOW-LEVEL SOUTHERLY JET. BY EARLY EVENING WE EXPECT
WINDS TO SHIFT TO THE SOUTH AND INCREASE DRASTICALLY. ONGOING GALE
WARNING FOR OFFSHORE GA WATERS IS STILL ON TRACK. GIVEN THE WARM
ADVECTION REGIME AND THE COOL WATERS NEAR SHORE...EVEN WITH ROBUST
GEOSTROPHIC WINDS WE DO NOT ANTICIPATE GALE CONDITIONS OUTSIDE OF
THE CURRENT WARNING. HOWEVER...SOLID SMALL CRAFT ADVISORY
CONDITIONS WILL DEVELOP ACROSS THE NEARSHORE WATERS AND CHARLESTON
HARBOR THIS EVENING AND CONTINUE OVERNIGHT.
SATURDAY...DANGEROUS MARINE CONDITIONS WILL BE ONGOING AND
PERSIST THROUGH THE DAY IN RESPONSE TO INTENSIFYING LOW PRESSURE
OFF THE DELMARVA. STEADY ISALLOBARIC PRESSURE RISES INTO THE
AFTERNOON WILL COINCIDE WITH THE BEST COLD ADVECTION. THIS WILL
EASILY SUPPORT SMALL CRAFT ADVISORIES FOR WEST/NW WINDS OF 20-30
KT ACROSS THE 0-20 NM WATERS AND CHARLESTON HARBOR. ACROSS THE
OUTER GA WATERS WE HAVE CONTINUED THE GALE WARNING UNTIL 18Z...BUT
ONCE THAT COMES DOWN WE/LL NEED TO TRANSITION OVER TO A SMALL
CRAFT ADVISORY.
SATURDAY NIGHT...THERE IS ENOUGH IMPROVEMENT IN WINDS/SEAS AS HIGH
PRESSURE BUILDS FROM THE WEST AND THE GRADIENT RELAXES
SOME...ALLOWING FOR ALL ADVISORIES TO COME DOWN EXCEPT FOR AMZ374
WHERE WINDS ARE STILL AS HIGH AS 25 KT AND SEAS OF 6 OR 7 FT.
SUNDAY...THIS LOOKS TO BE THE BETTER OF THE TWO WEEKEND
DAYS...ALTHOUGH WINDS AND SEAS WILL STILL BE SOMEWHAT ELEVATED
BETWEEN A HIGH PRESSURE RIDGE FROM THE GULF ACROSS FLORIDA AND LOW
PRESSURE IN THE OHIO VALLEY. WEST AND SW WINDS WILL BE CAPPED AT 15
OR MAYBE 20 KT AND SEAS 5 FT OR LESS.
SUNDAY NIGHT AND MONDAY...ANY IMPROVEMENT IN MARINE CONDITIONS WILL
HAVE ONLY BEEN TEMPORARY AS A CLIPPER-TYPE LOW MOVES OFF THE
MID-ATLANTIC COAST AND A TRAILING COLD FRONT SWINGS THROUGH LATE
SUNDAY NIGHT. THE PRESSURE PATTERN WILL TIGHTEN AGAIN AROUND THE LOW
TO THE NORTH SUNDAY NIGHT BEFORE IT PULLS OFF TO THE EAST/NE MONDAY.
WINDS AND SEAS WILL AGAIN RISE AND ADDITIONAL SMALL CRAFT ADVISORIES
SEEM LIKELY.
TUESDAY THROUGH WEDNESDAY...FOR THE MOMENT IT LOOKS LIKE WE/LL BE
BELOW ANY ADVISORY CONDITIONS BETWEEN LOW PRESSURE IN THE WESTERN
ATLANTIC AND HIGH PRESSURE DEVELOPING OUT OF THE NORTHERN PLAINS AND
OHIO VALLEY.
&&
.TIDES/COASTAL FLOODING...
DO NOT EXPECT THIS EVENING/S HIGH TIDE TO REACH ADVISORY CRITERIA
AT CHARLESTON NOR SAVANNAH AS THE ANOMALY WOULD NEED TO BE MORE
THAN 1.3 FEET. WINDS BECOMING SOUTHERLY THIS EVENING SHOULD REDUCE
THE SURGE CONSIDERABLY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST SATURDAY FOR AMZ330-350-
352-354.
GALE WARNING UNTIL 1 PM EST SATURDAY FOR AMZ374.
&&
$$
NEAR TERM...JRL
SHORT TERM...33
LONG TERM...DPB
AVIATION...33/JRL
MARINE...33/JRL
TIDES/COASTAL FLOODING...JRL
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
248 PM EST FRI JAN 23 2015
.SYNOPSIS...
RAIN WILL DOMINATE THE REGION AS THE LOW MOVES NORTHEASTWARD AND
ACROSS THE LOW COUNTRY THIS EVENING. THE LOW WILL REACH THE OUTER
BANKS TONIGHT AND FURTHER AWAY FROM THE AREA ON SATURDAY. WEAK
HIGH PRESSURE WILL CONTROL THE AREA SUNDAY WITH ANOTHER FAST
MOVING SYSTEM CROSSING THE REGION SUNDAY NIGHT AND MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
A SOUTHERN STREAM UPPER TROUGH OVER THE SOUTH CENTRAL US WILL
SWING TOWARD THE CAROLINAS TONIGHT. LOW PRESSURE CURRENTLY ALONG
THE FLORIDA PANHANDLE WILL CONTINUE MOVING NORTHEASTWARD ACROSS
SOUTHEAST GEORGIA AND TOWARD THE LOW COUNTRY OF SOUTH CAROLINA.
STILL A BIT OF UNCERTAINTY IN THE EXACT TRACK OF THE LOW WITH THE
NAM A BIT FURTHER EAST THAN THE GFS. THE WPC PREFERRED TRACK IS
CLOSER TO THE GFS SOLUTION SHOWING IT TRACKING THROUGH THE EASTERN
EDGE OF THE FORECAST AREA. QPF AMOUNTS SO FAR TODAY HAVE BEEN LESS
THAN MODEL GUIDANCE LIKELY DUE TO MOISTURE GETTING CUT OFF WITH
CONVECTION ALONG THE GULF. MODELS SHOW THE HIGHEST PRECIPITABLE
WATER VALUES DURING THE 21Z TO 06Z TIME FRAME AS THE LOW NEARS THE
AREA. INCREASED CONVERGENCE IN THE VICINITY OF THE LOW AND BEST
MOISTURE SUPPORT HIGHEST POPS DURING THIS TIME FRAME. RAINFALL
WILL BEGIN TO DIMINISH DURING THE EARLY MORNING AS THE LOW CENTER
MOVES WELL NORTHEAST OF THE AREA. THE HRRR AND NSSL WRF SIMULATED
REFLECTIVITY MODELS SHOW MOST OF THE PRECIPITATION SHIFTING
NORTHEAST OF THE AREA AFTER 03Z. TEMPERATURES ARE FORECAST TO RISE
IN THE FAR EASTERN MIDLANDS AS THE WARM FRONT CROSSES THE AREA.
IN THE NORTHERN AND WESTERN MIDLANDS...TEMPERATURES FORECAST TO
DROP ONLY A FEW DEGREES OVERNIGHT.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
SATURDAY...LOW PRESSURE WILL CONTINUE TRACKING NORTH-NORTHEASTWARD ON
SATURDAY WITH MOISTURE DECREASING ACROSS THE AREA. MODELS DO SHOW
SOME WRAP-AROUND MOISTURE SATURDAY MORNING SO HAVE SHOWN POPS
TAPERING OFF THROUGH THE MORNING FROM SOUTHWEST TO NORTHEAST. MOST
OF THE RAIN SHOULD BE OUT OF THE AREA BY SATURDAY AFTERNOON AS
HIGH PRESSURE RIDGES INTO THE AREA FROM THE WESTERN GULF. CLOUD
COVER WILL DECREASE AS DRIER AIR ADVECTS INTO THE AREA. EXPECT
SLIGHTLY BELOW NORMAL HIGH TEMPERATURES IN THE LOW TO MID 50S.
MAINLY CLEAR SKIES OVERNIGHT WILL ALLOW FOR DECENT RADIATIONAL
COOLING ALTHOUGH LIGHT WINDS ARE FORECAST SO DO NOT EXPECT IDEAL
CONDITIONS. FORECASTING LOWS IN THE LOW TO MID 30S.
SUNDAY...HIGH PRESSURE WILL MOVE THROUGH THE AREA SUNDAY AS A
STACKED LOW PRESSURE SYSTEM APPROACHES FROM THE WEST. THIS FAST
MOVING SYSTEM WILL SWING THROUGH SUNDAY NIGHT. THE BETTER
MOISTURE WILL REMAIN TO OUR NORTH...SO HAVE CONTINUED TO INDICATE
ONLY SLIGHT CHANCE POPS SUNDAY NIGHT IN THE NORTHERNMOST COUNTIES.
INCREASING CLOUDS ON SUNDAY WITH NEAR NORMAL HIGHS TOPPING OUT IN
THE MID TO UPPER 50S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
NOT MUCH CHANGE IN THE THINKING FOR THE EXTENDED PERIODS AS MEDIUM
RANGE MODELS CONTINUE TO ADVERTISE A HIGHLY AMPLIFIED 500MB FLOW
PATTERN FEATURING A WESTERN RIDGE AND EASTERN TROUGH.
A LEAD SHORTWAVE TROUGH AND ASSOCIATED SURFACE LOW WILL PUSH
EASTWARD OFF THE MID-ATLANTIC COAST LEAVING THE FORECAST AREA WITHIN
A NORTHWESTERLY FLOW REGIME AND COLD ADVECTION. SKIES SHOULD BE
CLEARING THROUGH THE DAY AS DRIER AIR BUILDS INTO THE REGION WITH
HIGH PRESSURE. TEMPERATURES EXPECTED TO BE NEAR TO SLIGHTLY BELOW
NORMAL MONDAY WITH HIGHS GENERALLY IN THE MID 50S.
THE UPPER TROUGH AXIS WILL EXTEND FROM EASTERN CANADA DOWN TO THE
CAROLINAS BY TUESDAY MORNING AND ANOTHER FAST MOVING SHORTWAVE
TROUGH WILL ROTATE THOUGH THE BASE OF THE TROUGH BRINGING A DRY COLD
FRONT THROUGH THE AREA BY TUESDAY EVENING. LITTLE MOISTURE WILL BE
AVAILABLE FOR THE FRONT SO DRY WEATHER IS FORECAST. TEMPERATURES
WILL BE BELOW NORMAL TUE/WED WITH PERSISTENT NORTHERLY LOW LEVEL
FLOW AS A 1033MB SURFACE RIDGE BUILDS OVER THE OHIO VALLEY INTO THE
CAROLINAS MID WEEK. HIGHS GENERALLY EXPECTED IN THE 40S TO LOWER
50S WHILE OVERNIGHT LOWS FALL INTO THE 20S TO NEAR 30 DEGREES.
A FLATTENING UPPER RIDGE WILL SHIFT OVER THE FORECAST AREA ON
THURSDAY IN RESPONSE TO YET ANOTHER FAST MOVING SHORTWAVE TROUGH
MOVING THROUGH THE BROAD NORTHWESTERLY 500MB FLOW. TEMPERATURES
SHOULD REBOUND A BIT BACK TO NEAR NORMAL VALUES ON THURSDAY WITH A
WEAK AND DRY FRONT PUSHING THROUGH THE AREA THURSDAY NIGHT INTO
FRIDAY MORNING.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
WIDESPREAD RAIN CONTINUES TO OVERSPREAD THE TERMINALS AS
ISENTROPIC LIFT CONTINUES AHEAD OF AN APPROACHING LOW PRESSURE
SYSTEM. CIGS HAVE FALLEN TO MVFR CATEGORY AND ALL TERMINALS SHOULD
DROP TO IFR CIGS BETWEEN 19Z-22Z...WITH LOWER CONFIDENCE ON VSBYS
BUT WILL CONTINUE MVFR VSBYS IN RAIN THROUGHOUT THE AFTERNOON AND
EVENING.
MODEL TRENDS ARE SHOWING THE WIDESPREAD RAIN PUSHING OUT OF THE
AREA EARLIER...AFTER 03Z OR SO ALTHOUGH THE UPPER SYSTEM WILL
REMAIN TO THE WEST...SO WILL CONTINUE WITH SOME DRIZZLE OVERNIGHT
AND IFR/LIFR CIGS. AFTER THE SURFACE LOW PASSES DURING THE 04Z-06Z
TIME FRAME...NORTHEASTERLY WINDS AROUND 10 MPH WILL SHIFT TO THE
WEST AND INCREASE AS THE PRESSURE GRADIENT STRENGTHENS WITH THE
SURFACE LOW DEEPENING AS IT MOVES AWAY FROM THE REGION. WINDS WILL
PICK UP TO 10 TO 15 MPH WITH GUSTS TO 25-30 MPH AFTER 12Z-14Z.
HAVE CONTINUED THE MENTION OF LOW LEVEL WIND SHEAR THIS AFTERNOON
WITH STRONG WINDS JUST ABOVE THE STABLE BOUNDARY LAYER.
SOME IMPROVEMENT IN CIGS EXPECTED AFTER 15Z SATURDAY BUT WILL OPT
TO KEEP MVFR CIGS GOING THROUGH THE END OF THIS FORECAST.
EXTENDED AVIATION OUTLOOK...POSSIBLE RESTRICTIONS ON MONDAY AS
ANOTHER SYSTEM MOVES THROUGH THE REGION BUT CONFIDENCE IS LOW AT
THIS TIME.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
305 PM CST FRI JAN 23 2015
.SHORT TERM...
TONIGHT AND SATURDAY...
305 PM...NO CONCERNS THROUGH SATURDAY EVENING. LOW CLOUDS CONTINUE
TO ERODE FROM THE NORTH AND THE SOUTHWEST THIS AFTERNOON. THIS
TREND WILL CONTINUE THIS EVENING AS THE BACK EDGE PUSHES EAST.
HOWEVER...AN EXTENSIVE BAND OF MID CLOUDS WILL SPREAD BACK ACROSS
THE AREA THIS EVENING AHEAD OF AN APPROACHING COLD FRONT. VERY
LIMITED MOISTURE WITH THIS FRONT AND NOT EXPECTING ANY PRECIP
THOUGH A SPRINKLE OR FLURRY CAN/T BE COMPLETED RULED OUT...BUT NO
MENTION IN THE FORECAST. CLOUD COVER HELPED HOLD HIGHS TODAY IN
THE LOWER/MID 30S AND WITH SOME PARTIAL CLEARING AT TIMES...EXPECT
LOWS TONIGHT TO DIP INTO THE MID/UPPER 20S...THOUGH SOME
UNCERTAINTY WITH APPROACHING MID CLOUDS AND THEN ANOTHER AREA OF
LOW CLOUDS OVER THE UPPER MIDWEST WHICH WILL BE SPREADING SOUTH
ACROSS THE AREA SATURDAY MORNING. IF THIS CLOUD COVER DOES BECOME
OVERCAST...HIGHS ON SATURDAY WILL LIKELY BE TEMPERED SOME AS
WELL...PERHAPS ONLY IN THE MID 30S. CMS
&&
.LONG TERM...
SATURDAY NIGHT THROUGH FRIDAY...
305 PM...MAIN FORECAST CONCERN IS ACCUMULATING SNOW LATE SATURDAY
NIGHT THROUGH SUNDAY AFTERNOON...WITH POSSIBLE LAKE EFFECT SNOW
SHOWERS SUNDAY NIGHT AND ANOTHER WEAKER CLIPPER SYSTEM MONDAY
NIGHT...FOLLOWED BY MODERATE/MILD TEMPS MIDDLE OF NEXT WEEK.
DECENT AGREEMENT WITH THE TRACK OF THE SURFACE LOW OF THE NEXT
CLIPPER SYSTEM SATURDAY NIGHT INTO SUNDAY WITH THE 12Z GFS A BIT
FURTHER SOUTHWEST OF THE REST OF THE MODELS...WHICH TRACK THE LOW
FROM ROUGHLY MLI TO IND SUNDAY MORNING. THERMAL PROFILES SUGGEST
PRECIP TYPE WILL BE ALL SNOW...BUT INITIALLY COULD BE SOME RAIN
MIXED IN ACROSS THE SOUTHERN CWA. IN ADDITION...SNOW/WATER RATIOS
COULD BE RATHER LOW TO START...YIELDING A WETTER SNOW. BUT AS THE
LOW TRACKS TO THE SOUTHEAST...COLDER AIR WILL SLOWLY SPREAD ACROSS
THE AREA WITH THE SNOW LIKELY BECOMING DRIER BY LATE MORNING AND
INTO THE AFTERNOON. THIS MAKES SNOWFALL AMOUNTS A BIT TRICKY...
ESPECIALLY IF THE TRACK OF THE LOW ENDS UP A LITTLE FURTHER SOUTH
AS THE GFS SUGGESTS...COLDER AIR WOULD ARRIVE SOONER. POSSIBLE
LAKE ENHANCEMENT WITH NORTHEAST FLOW ALSO ADDS TO THE UNCERTAINTY
REGARDING AMOUNTS. THEREFORE...DIDN/T MAKE ANY SIGNIFICANT
CHANGES TO THE GOING FORECAST WITH 2-4 INCHES NORTH OF A SQI/IKK
LINE...1-2 INCHES SOUTH OF THAT LINE. BUT AS IS ALWAYS THE
CASE...MINOR CHANGES IN THE TRACK COULD CAUSE LARGE CHANGES TO THE
FORECAST AS TRENDS EMERGE.
TEMPERATURES BEGIN TO FALL BY MID/LATE SUNDAY AFTERNOON ACROSS THE
NORTH. NORTHEASTERLY WINDS INCREASE WITH GUSTS TO 30 MPH AND
DEPENDING ON HOW DRY THE SNOW BECOMES...THERE COULD BE SOME
BLOWING SNOW BUT AGAIN...ITS TOO EARLY FOR SPECIFICS OR HOW MUCH
OF A PROBLEM THIS COULD BECOME.
THE NORTHEAST AND THEN NORTHERLY WINDS MAY ALLOW SOME LAKE EFFECT
SNOW SHOWERS TO DEVELOP SUNDAY EVENING ACROSS NORTHEAST IL AND
THEN INTO NORTHWEST INDIANA. BUT INVERSION HEIGHTS ARE RATHER
LOW...PERHAPS NO HIGHER THAN 4KFT AND WINDS BEGIN TO TURN BACK
EASTERLY BY MONDAY MORNING. THUS ANY LAKE EFFECT POTENTIAL LOOKS
MINIMAL.
ANOTHER CLIPPER QUICKLY DROPS SOUTHEAST ACROSS THE WESTERN LAKES
MONDAY AFTERNOON INTO MONDAY NIGHT...AS IT BEGINS TO WEAKEN. A
BAND OF LIGHT SNOW IS POSSIBLE WITH THIS FEATURE ESPECIALLY MONDAY
EVENING AND SOME AREAS MAY SEE AN INCH OR TWO DEPENDING ON WHERE
IT TRACKS. HAVE INCLUDED JUST LIGHT QPF AMOUNTS FOR NOW.
HIGH PRESSURE MOVES ACROSS THE AREA TUESDAY AND TUESDAY NIGHT AS
FLOW TURNS BACK SOUTH WEDNESDAY AND TEMPS MODIFY BACK INTO THE 30S
THOUGH WITH AN EXPECTED SNOWPACK BY THEN...LOW CONFIDENCE ON HOW
WARM TEMPS WILL BECOME. ANOTHER CLIPPER SYSTEM MOVES ACROSS THE
LAKES REGION WEDNESDAY NIGHT AND THURSDAY...WITH A CHANCE OF LIGHT
RAIN OR LIGHT SNOW WEDNESDAY NIGHT INTO THURSDAY MORNING. CMS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* MVFR CIGS ARND 1500-1800FT AGL...SLOWLY LIFTING TO ARND 2KFT AGL
AFT 00Z.
* SOUTHWEST WINDS ARND 10-14KT WITH OCCASIONAL GUSTS TO 15-17KT
THRU 00Z.
BEACHLER
//DISCUSSION...UPDATED 18Z...
VISIBLE IMAGERY THIS MORNING CONTINUED TO SHOW CONSIDERABLE CLOUD
COVER ACROSS THE REGION...WITH SOME CLEARING NOTED ACROSS EASTERN
IOWA. AS THE DAY HAS PROGRESSED SOME THINNING HAS BEGUN TO TAKE
PLACE ACROSS FAR NORTH/NORTHEAST ILLINOIS...AND MAY EVENTUALLY
MAKE IT INTO THE TAF SITES. AT THIS TIME THOUGH HAVE HELD ONTO THE
LOW CLOUDS THRU 00Z...WITH A SLOW IMPROVEMENT TOWARDS 2000-2500FT
AGL AFT 02Z. WINDS WILL CONTINUE TO BE SOUTHWESTERLY WITH SPEEDS
GENERALLY FROM 10-13KT. THRU THE AFTN ON OCCASION GUSTS MAY
OCCUR...AND NOT EXPECTED TO BE VERY FREQUENT WITH SPEEDS UP TO
17KT.
WITH A FRONTAL BOUNDARY SLIDING SOUTHEAST THIS EVENING...THERE IS
THE POTENTIAL FOR A FEW FLURRIES ACROSS ORD/MDW/DPA. ELSEWHERE
SHOULD BE TOO FAR REMOVED FROM THE BETTER MOISTURE TO SEE ANY
FLURRIES. THOUGH HAVE HELD ONTO A DRY FORECAST AS THIS TOO IS A
LOW CONFIDENCE.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE IN CIGS REMAINING OVC THRU 23Z...MEDIUM
CONFIDENCE IN TIMING OF CIGS LIFTING HIGHER.
* HIGH CONFIDENCE IN WIND DIR/SPEED.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SNOW LIKELY AFTER MIDNIGHT. ACCUMULATION LIKELY.
MVFR CIGS AND IFR VIS POSSIBLE.
SUNDAY...SNOW LIKELY. MVFR/IFR LIKELY.
MONDAY...CHANCE OF SNOW SHOWERS. MVFR POSSIBLE.
TUESDAY THROUGH THURSDAY...PRIMARILY VFR.
RATZER
&&
.MARINE...
122 PM CST
SOUTHWESTERLY WINDS WILL GRADUALLY WEAKEN TONIGHT...THEN A COLD
FRONT WILL SHIFT OVER THE LAKE ON SATURDAY AS THE PARENT SURFACE LOW
TRACKS ACROSS NORTHERN QUEBEC. THIS WILL SET UP A NORTHERLY FLOW
DOWN THE LAKE LATER SATURDAY. A FAST MOVING STOUT CLIPPER SYSTEM
WILL MOVE SOUTH OF THE LAKE ON SUNDAY MORNING...AND THIS LOOKS TO
SET THE STAGE FOR A PERIOD OF STRONG NORTHEASTERLY WINDS UP AROUND
30 KT OVER THE LAKE. THIS WILL LIKELY PRODUCE HIGH WAVES OVER 5 FEET
ACROSS MUCH OF SOUTHERN END OF LAKE MICHIGAN SUNDAY AND SUNDAY NIGHT.
FOLLOWING THIS SYSTEM...ANOTHER STORM SYSTEM IS EXPECTED TO IMPACT
THE GREAT LAKES REGION FOR THE MIDDLE TO END OF NEXT WEEK. IT
APPEARS THIS COULD PRODUCE SOUTHERLY GALE FORCE WINDS OVER MUCH OF
THE LAKE LATE WEDNESDAY AND WEDNESDAY NIGHT...FOLLOWED BY A PERIOD
OF POTENTIALLY GALE FORCE NORTHERLY WINDS THURSDAY AS THE SYSTEM
PASSES OVER THE EASTERN LAKES.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3
PM FRIDAY.
&&
$$
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[top]
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
248 PM CST Fri Jan 23 2015
.SHORT TERM...(Tonight)
ISSUED AT 247 PM CST FRI JAN 23 2015
Clearing line from the morning stratocumulus deck was unable to make
any further eastward progress, so the clouds decided to dissolve in
place instead. 2 pm visible satellite imagery showing most areas
west of I-55 now mostly sunny, with the clouds rapidly eroding on
the western flank of what`s left. The clear skies won`t last too
long though, as mid-level cloud deck ahead of the next frontal
boundary is already in southeast Iowa. The boundary itself is still
back across eastern Nebraska through the Minneapolis area, and will
be moving through our forecast area between midnight and sunrise.
However, no precipitation is expected with it. Lows across the
forecast area should fall into the upper 20s.
&&
.LONG TERM...(Saturday through Friday)
ISSUED AT 247 PM CST FRI JAN 23 2015
By and large, the forecast period will be dominated by a ridge
west/trof east pattern across North America, a pattern that has been
pretty common of late. The fast moving northwest upper-level flow
that has been over the forecast area has had numerous, mainly weak,
impulses embedded within it traveling over or in our vicinity. Most
of these waves lately, and those expected over the next several
days, have been too weak and/or moisture starved to produce much
precipitation locally. This trend should continue to be the case for
most of the days of this forecast. However, a more significant
clipper system still appears on track to impact the area late
Saturday night into Sunday night. This system is our primary
forecast concern today.
A weak upper/surface trof will move across the area later
tonight/early Saturday, but it is only expected to be accompanied by
an increase in cloud cover. This cloud cover is currently evident
upstream from the Great Lakes into the central Plains.
The timing of the main clipper is pretty well agreed upon, and has
been for a few days now, with the primary precipitation risk
occurring late Saturday night/early Sunday Morning into Sunday
afternoon. However, the track of the system continues to exhibit
considerable model spread, as well as run-to-run variability. The
overall model trend had been toward a more northerly track until
about 24 hours ago, but now the trend is back toward the south. The
northern track would have resulted in minimal precipitation risk for
the forecast area, with the bulk of it falling in the form of rain.
The more southern track, most pronounced in the latest run of the
GFS, would support more widespread precipitation locally, with at
least the northern portion of the forecast area in line for some
accumulating snow. Forecast confidence in the details with this
system remains low considering the variability/inconsistency.
However, given the trends of the past 24 hours, have boosted PoPs
into the Likely category for much of the forecast area on Sunday,
and added some light snow accumulation across the north. If the
models lock into a more southern solution, one that takes the
clipper just south of the forecast area like the current GFS,
temperatures will need to be lowered, PoPs raised, and snow amounts
boosted. For now, will be conservative with the changes until the
ultimate outcome is a little more clear.
For the remainder of the period, mostly quiet weather is expected. A
weak wave is most likely to impact the area Monday and again by
Thursday. However, these disturbances appear too weak to carry
mentionable precipitation at this time. Temperatures through the end
of the next work week should be at or above normal. The coolest
readings are likely Monday/Tuesday behind the main clipper, and
again Friday behind Thursday`s disturbance.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
ISSUED AT 1123 AM CST FRI JAN 23 2015
Main concern in the short term will be with the timing of the
lifting of MVFR ceilings today. Clearing trend is making painfully
slow progress eastward. Have adjusted the timing of the clouds
scattering out based on the RAP model humidity level around 2000
feet, which would bring it to KPIA/KSPI around 23Z and to KCMI
around 01Z or so. This is a faster than a straight timing of the
cloud deck`s movement, as there are some thinning spots starting
to show up west of KPIA hinting at some potential afternoon
erosion, as suggested by the HRRR model. Any clearing will not
last terribly long, as mid and high clouds are already approaching
ahead of a frontal boundary that will be moving through the TAF
sites in the 10-14Z time frame on Saturday. While the front will
be dry, MVFR ceilings are likely to overspread central Illinois
Saturday morning following passage of the front.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Geelhart
LONG TERM...Bak
AVIATION...Geelhart
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1202 PM CST FRI JAN 23 2015
.SHORT TERM...
302 AM CST
THROUGH SATURDAY...
EARLY MORNING WATER VAPOR IMAGERY SHOWS A CLOSED UPPER LOW
SPINNING OVER TEXAS AS PART OF A LARGER SCALE TROUGH THAT IS CUT
OFF FROM THE MAIN STREAM OF FLOW TO THE NORTH. THIS MAIN STREAM IS
POSITIONED ACROSS SOUTHERN CANADA WITH WITH SEVERAL EMBEDDED WAVES
TRACKING ACROSS MANITOBA AND SASKATCHEWAN TOWARD THE UPPER MIDWEST
AND UPPER GREAT LAKES. FURTHER WEST...LOW AMPLITUDE RIDGING IS
POSITIONED OVER THE WEST COAST WITH A WELL- DEFINED TROUGH MOVING
EASTWARD TOWARDS BRITISH COLUMBIA. AT THE SURFACE...HIGH PRESSURE
IS STRETCHED FROM THE SOUTHERN PLAINS TO NEW ENGLAND WITH A
SURFACE LOW OFF THE LOUISIANA COAST IN CONJUNCTION WITH THE TEXAS
UPPER LOW. ANOTHER SURFACE LOW IS OVER NORTHERN ONTARIO IN
CONJUNCTION WITH ONE OF THE WAVES OVER CENTRAL CANADA WITH A
TROUGH AXIS EXTENDING SOUTHWARD ACROSS THE NORTHERN PLAINS.
ABUNDANT BUT THIN CLOUD COVER REMAINS ACROSS THE REGION WITH
SATELLITE SHOWING VERY SLOW EASTWARD MOVEMENT...WITH THE BACK EDGE
STILL ACROSS EASTERN IOWA.
THE CLOUD COVER WILL BE THE MAIN CHALLENGE TODAY. FORECAST SOUNDINGS
SHOW A MIX OF THOUGHTS ON HOW LONG CLOUD COVER WILL HANG ON AND DO
NOT SEE MUCH IMPROVEMENT THROUGH LATE MORNING...THOUGH WESTERN AREAS
HAVE THE BEST CHANCE FOR SCATTERING BY MIDDAY. THE PRESSURE GRADIENT
WILL BEGIN TO TIGHTEN UP AS THE ONTARIO SURFACE LOW MOVES EAST AND
THE ASSOCIATED TROUGH APPROACHES. THIS WILL ALLOW FOR STEADIER
SOUTHWEST WINDS TO DEVELOP. WITH THE IDEA THAT CLOUDS WILL HANG ON
THROUGH THE MORNING THEN SCATTER THIS AFTERNOON...HIGH TEMPS WILL
PROBABLY STRUGGLE DESPITE THE SOUTHWEST WINDS AND MODEST WARM
ADVECTION ALOFT. WILL CONTINUE WITH MID AND UPPER 30S FOR NOW BUT IF
SUN CAN MAKE AN APPEARANCE FOR SEVERAL HOURS THIS AFTERNOON THEN
HIGHS AROUND 40/LOW 40S WOULD BE PLAUSIBLE. A BAND OF MID CLOUDS
WILL ACCOMPANY THE TROUGH PASSAGE EARLY THIS EVENING WITH A FEW
FLURRIES NOT OUT OF THE QUESTION. WINDS TURN NORTHWEST TONIGHT AND
SATURDAY MORNING WITH COOL ADVECTION OCCURRING. CLOUD COVER LOOKS
ABUNDANT SO HIGHS WILL LIKELY BE HELD IN THE MID/UPPER 30S.
MDB
&&
.LONG TERM...
302 AM CST
SATURDAY NIGHT THROUGH MONDAY...ATTENTION TURNS TO THE UPPER TROUGH
OFF THE BRITISH COLUMBIA COAST THIS MORNING. A SHORTWAVE EJECTS FROM
THIS TROUGH AND TRACKS EAST THEN SOUTHEAST AND ACROSS THE LOCAL AREA
EARLY SUNDAY. SURFACE LOW PRESSURE DEVELOPS AND PASSES WITH THE
UPPER TROUGH DURING THE DAY SUNDAY. GUIDANCE CONTINUES TO DISAGREE
ON THE STRENGTH AND TRACK OF THE SYSTEM WITH RECENT RUNS SHOWING
QUITE A BIT OF VARIATION. THESE NORTHWEST SYSTEMS HAVE HAD A
TENDENCY TO TRACK FURTHER SOUTH OR SOUTH AND WEST THAN DEPICTED
AHEAD OF TIME SO WILL NEED TO KEEP A CLOSE EYE ON THE WAVE AS IT
MOVES ONSHORE OVER BRITISH COLUMBIA LATER TONIGHT. AT THIS POINT...A
LOW TRACK ACROSS NORTHWEST OR WEST-CENTRAL ILLINOIS...SIMILAR TO THE
00Z GFS/ECMWF...LOOKS TO BE FAVORED WHEN CONSIDERING THE CURRENT AND
EXPECTED UPPER FLOW PATTERN. WITH WESTERN RIDGING EXPECTED TO
SHARPEN AS MORE PACIFIC ENERGY PUSHES INTO IT FROM THE WEST...THE
FLOW OVER THE ROCKIES/PLAINS WILL TURN MORE NORTHWESTERLY. ONE COULD
MAKE THE CASE THAT IF THE WAVE WERE TO TRACK THROUGH THE CURRENT
UPPER FLOW PATTERN IT WOULD TAKE A TRACK ACROSS THE AREA SO A MORE
NORTHWESTERLY FLOW WOULD SUPPORT A MORE WESTERN TRACK. A TRACK
FURTHER NORTH/EAST SEEMS UNLIKELY BUT WOULD NOT BE SURPRISED TO SEE
IT TRACK WEST OF THE TRACK OF THE 00Z GFS/ECMWF BASED ON THE
ABOVE. GIVEN THE PACIFIC ORIGINS OF THE SYSTEM THERE WILL BE
MOISTURE TO WORK WITH SO PRECIPITATION IS LIKELY WITH IT AND SHOULD
AFFECT MOST OF THE AREA UNLESS A WILD SWING IN THE TRACK OCCURS.
PRECIP TYPE MAY BE MIXED FOR A TIME AT ONSET...MAINLY SOUTH AND WEST
WITH A MORE SOUTH/WEST TRACK LEADING TO MAINLY SNOW FOR MUCH OF THE
AREA. THE 00Z RUN OF THE GFS/ECMWF SUGGEST A MIX EARLY SOUTH AS A
NOSE OF WARM AIR BRIEFLY BUILDS IN BEFORE COLD AIR FILLS IN AGAIN.
BASED ON PRECIPITABLE WATER VALUES AND DURATION OF FORCING THE HEART
OF THE SYSTEM LOOKS TO BE ABLE TO PRODUCE 0.3 TO PERHAPS 0.4 INCHES
OF LIQUID EQUIVALENT PRECIP WITH IT BECOMING A MATTER OF WHERE THE
HEART OF THE SYSTEM TRACKS.
ANOTHER ISSUE WILL BE THE POTENTIAL FOR LAKE ENHANCEMENT AS THE LOW
PASSES SUNDAY AFTERNOON/EVENING. A LOW TRACK TO THE SOUTH AND WEST
OF THE AREA WOULD BE SUPPORTIVE OF LAKE ENHANCEMENT OF SYNOPTIC
PRECIP ON THE BACK SIDE WITH THE COLUMN COLD ENOUGH TO SUPPORT SNOW
IN THIS SCENARIO. HIGH PRESSURE MOVES SOUTHWARD ACROSS ONTARIO INTO
MONDAY WITH ANOTHER SURFACE LOW/ELONGATED TROUGH STRETCHING FROM
MANITOBA TO THE CENTRAL PLAINS WHICH WILL TURN WINDS MORE EASTERLY
THEN SOUTHERLY INTO MONDAY EVENING. WITH FORECAST SOUNDINGS SHOWING
MARGINAL INVERSION HEIGHTS BUT SUFFICIENT DELTA T`S...MAY SEE A
SITUATION SIMILAR TO LAST WEEK WHERE LAKE EFFECT SNOW SHOWERS
PERSISTED IN THE EASTERLY LOW LEVEL FLOW BEFORE ENDING. THIS COULD
BE THE CASE FOR MUCH OF MONDAY. AS FAR AS TEMPS...HIGHS SUNDAY WILL
BE DICTATED BY THE LOW TRACK AND MONDAY LOOKS TO ONLY SEE HIGHS IN
THE 20S THANKS TO COLD ADVECTION.
TUESDAY THROUGH THURSDAY...BROAD RIDGING WEST AND TROUGHING EAST
WILL LEAVE THE LOCAL AREA UNDER A SHARP NORTHERLY UPPER FLOW
TUESDAY WITH HIGH PRESSURE AT THE SURFACE. THE RIDGING WILL
QUICKLY SHIFT EAST AND DE-AMPLIFY WEDNESDAY ALLOWING MILDER AIR TO
RETURN. THE FLOW MAY BE SOMEWHAT ACTIVE BUT PRECIP DETAILS ARE NOT
CLEAR AT THIS RANGE...THOUGH HAVE DECENT CONFIDENCE IN FAIRLY MILD
TEMPERATURES.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* MVFR CIGS ARND 1500-1800FT AGL THRU 00Z...SLOWLY LIFTING TO ARND
2KFT AGL AFT 2Z.
* SOUTHWEST WINDS ARND 10-14KT WITH OCCASIONAL GUSTS TO 15-17KT
THRU 00Z.
BEACHLER
//DISCUSSION...UPDATED 18Z...
VISIBLE IMAGERY THIS MORNING CONTINUED TO SHOW CONSIDERABLE CLOUD
COVER ACROSS THE REGION...WITH SOME CLEARING NOTED ACROSS EASTERN
IOWA. AS THE DAY HAS PROGRESSED SOME THINNING HAS BEGUN TO TAKE
PLACE ACROSS FAR NORTH/NORTHEAST ILLINOIS...AND MAY EVENTUALLY
MAKE IT INTO THE TAF SITES. AT THIS TIME THOUGH HAVE HELD ONTO THE
LOW CLOUDS THRU 00Z...WITH A SLOW IMPROVEMENT TOWARDS 2000-2500FT
AGL AFT 02Z. WINDS WILL CONTINUE TO BE SOUTHWESTERLY WITH SPEEDS
GENERALLY FROM 10-13KT. THRU THE AFTN ON OCCASION GUSTS MAY
OCCUR...AND NOT EXPECTED TO BE VERY FREQUENT WITH SPEEDS UP TO
17KT.
WITH A FRONTAL BOUNDARY SLIDING SOUTHEAST THIS EVENING...THERE IS
THE POTENTIAL FOR A FEW FLURRIES ACROSS ORD/MDW/DPA. ELSEWHERE
SHOULD BE TOO FAR REMOVED FROM THE BETTER MOISTURE TO SEE ANY
FLURRIES. THOUGH HAVE HELD ONTO A DRY FORECAST AS THIS TOO IS A
LOW CONFIDENCE.
BEACHLER
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN CIGS REMAINING OVC THRU 23Z...MEDIUM
CONFIDENCE IN TIMING OF CIGS LIFTING HIGHER THAN 1600FT AGL.
* HIGH CONFIDENCE IN WIND DIR/SPEED.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SNOW LIKELY AFTER MIDNIGHT. ACCUMULATION LIKELY.
MVFR CIGS AND IFR VIS POSSIBLE.
SUNDAY...SNOW LIKELY. MVFR/IFR LIKELY.
MONDAY...CHANCE OF SNOW SHOWERS. MVFR POSSIBLE.
TUESDAY THROUGH THURSDAY...PRIMARILY VFR.
RATZER
&&
.MARINE...
217 AM CST
MARINE WEATHER CONCERNS INCLUDE SOUTHWESTERLY GALES ACROSS NORTHERN
LAKE MICHIGAN TODAY...THEN A BRIEF PERIOD OF STRONG NORTHEAST-NORTH
WINDS 25-30 KTS OVER CENTRAL/SOUTHERN LAKE MICHIGAN SUNDAY.
A STRONG AREA OF LOW PRESSURE WAS MOVING SLOWLY EAST ACROSS FAR
NORTHERN ONTARIO EARLY THIS MORNING...WHILE A WEST-EAST ORIENTED
RIDGE OF HIGH PRESSURE WAS ACROSS THE MIDWEST REGION SOUTH OF THE
GREAT LAKES. SURFACE PRESSURE FALLS ACROSS ONTARIO AND WESTERN
QUEBEC HAVE TIGHTENED THE GRADIENT ACROSS THE NORTHERN LAKES...AND
WILL REMAIN SO INTO THIS AFTERNOON BEFORE WEAKENING AS THE LOW
REACHES JAMES BAY AND A TRAILING SURFACE TROUGH APPROACHES FROM THE
WEST. SOUTHWEST WINDS HAVE INCREASED WITH A 34 KT GUST NOTED AT PORT
INLAND MI WITHIN THE PAST HOUR...AND A GALE WARNING IS IN EFFECT FOR
THE NORTHERN HALF OR SO OF THE LAKE THROUGH MID-AFTERNOON. WINDS
WILL EASE BELOW GALE FORCE BY LATE AFTERNOON AS THE GRADIENT BEGINS
TO WEAKEN...AND WILL FURTHER DIMINISH TONIGHT.
ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP IN ASSOCIATION
WITH AN ALBERTA-CLIPPER OVER THE WEEKEND...WITH THE LOW DEEPENING
AND MOVING QUICKLY TO NORTHWEST ILLINOIS BY SUNDAY MORNING. WINDS
WILL BECOME NORTHEASTERLY SATURDAY NIGHT AS THE LOW APPROACHES...
AND ARE EXPECTED TO QUICKLY INCREASE TO NEAR 30 KT EARLY IN THE DAY
SUNDAY AS THE LOW MOVES INTO CENTRAL INDIANA. THE PERIOD OF STRONGER
WINDS APPEARS TO BE BRIEF...AS THE LOW BEGINS TO FILL AND RAPIDLY
EXITS THE REGION TO THE SOUTHEAST SUNDAY EVENING AND WEAK HIGH
PRESSURE RIDGING MOVES IN FROM THE NORTHWEST. WEAK HIGH PRESSURE
THEN LOOKS TO LINGER ACROSS THE WESTERN GREAT LAKES INTO EARLY NEXT
WEEK.
FOR THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS...BREEZY
OFFSHORE WINDS EXPECTED TODAY AND SATURDAY. SMALL CRAFT ADVISORY
CONDITIONS ARE EXPECTED TO DEVELOP QUICKLY SUNDAY MORNING DUE TO THE
STRONG WINDS FROM THE CLIPPER...WITH THE DIMINISHING NORTH FETCH
KEEPING HIGHER WAVES LINGERING INTO EARLY MONDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3
PM FRIDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSCHICAGO
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1124 AM CST Fri Jan 23 2015
.UPDATE...
ISSUED AT 959 AM CST FRI JAN 23 2015
Have updated the forecast to slow the clearing trends and lower
the highs as a result. Clearing line is now just crossing the
Illinois/Iowa border. The latest RAP 925 mb humidity, which
appears to match the clouds fairly well, holds off on any
significant clearing in the northwest CWA until around mid
afternoon and not in the eastern CWA until after sunset. Have gone
with highs in the upper 30s over nearly all the forecast area,
except around 40 in west central Illinois where there is likely to
be some sunshine by mid to late afternoon.
&&
.SHORT TERM...(Today)
ISSUED AT 443 AM CST FRI JAN 23 2015
08z/2am IR satellite imagery shows low clouds blanketing central
Illinois, as moisture remains trapped beneath a subsidence inversion
centered around 900mb. With only very light low-level flow under
prevailing surface high pressure, am not expecting the clouds to
clear out anytime soon. HRRR suggests clouds will remain in place
through the morning, then will slowly begin to clear from west to
east during the afternoon. Based on satellite timing tools, think
clearing will be slightly faster, reaching the Illinois River Valley
by mid to late morning and the I-55 corridor by early afternoon.
The far E/NE KILX CWA around Champaign and Danville will likely
remain overcast through the entire day. High temperatures will
range from the upper 30s across the east where clouds will persist
longest to the lower 40s along/west of I-55 where sunshine will
prevail this afternoon.
&&
.LONG TERM...(Tonight through Thursday)
ISSUED AT 443 AM CST FRI JAN 23 2015
Weak short-wave trough currently evident on water vapor imagery over
southern Manitoba will drop into the Great Lakes tonight. Any light
precip associated with this feature will remain well north of
central Illinois: however, a weak frontal boundary will push through
the area, allowing winds to switch to northwesterly by morning.
Mild and dry conditions will be on tap behind the departing system
for Saturday with high temperatures topping out in the lower to
middle 40s.
Next more significant short-wave is still on target for Sunday, with
good model agreement concerning the strength and track of this
system. Surface low pressure will drop out of Canada on Saturday,
then will track from northeast Iowa Sunday morning to Ohio by Sunday
evening. With this particular track, the heaviest precipitation is
expected to remain further north along/north of the I-80 corridor.
Further south, the precip will be lighter and more scattered in
nature. Based on GFS/ECMWF timing, will introduce low chance PoPs
after midnight Saturday, with higher PoPs across the board during
the day Sunday. Atmospheric profile will remain marginal for snow,
so have only included a rain/snow mix along/north of I-74 Sunday
morning, before precip transitions to all rain by midday. May see a
change to light snow/flurries Sunday night as precip departs and
colder air returns, but no snow accumulation is expected.
After that, another wave will track well north of the area Monday
and Monday night: however, dry conditions are anticipated this far
south. Will be slightly cooler early next week as upper trough
remains in place across the eastern CONUS, resulting in highs in the
30s both Monday and Tuesday. The trough will shift eastward later
in the period, allowing temps to return to the 40s by Wednesday and
Thursday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
ISSUED AT 1123 AM CST FRI JAN 23 2015
Main concern in the short term will be with the timing of the
lifting of MVFR ceilings today. Clearing trend is making painfully
slow progress eastward. Have adjusted the timing of the clouds
scattering out based on the RAP model humidity level around 2000
feet, which would bring it to KPIA/KSPI around 23Z and to KCMI
around 01Z or so. This is a faster than a straight timing of the
cloud deck`s movement, as there are some thinning spots starting
to show up west of KPIA hinting at some potential afternoon
erosion, as suggested by the HRRR model. Any clearing will not
last terribly long, as mid and high clouds are already approaching
ahead of a frontal boundary that will be moving through the TAF
sites in the 10-14Z time frame on Saturday. While the front will
be dry, MVFR ceilings are likely to overspread central Illinois
Saturday morning following passage of the front.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Geelhart
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1007 AM CST FRI JAN 23 2015
.SHORT TERM...
302 AM CST
THROUGH SATURDAY...
EARLY MORNING WATER VAPOR IMAGERY SHOWS A CLOSED UPPER LOW
SPINNING OVER TEXAS AS PART OF A LARGER SCALE TROUGH THAT IS CUT
OFF FROM THE MAIN STREAM OF FLOW TO THE NORTH. THIS MAIN STREAM IS
POSITIONED ACROSS SOUTHERN CANADA WITH WITH SEVERAL EMBEDDED WAVES
TRACKING ACROSS MANITOBA AND SASKATCHEWAN TOWARD THE UPPER MIDWEST
AND UPPER GREAT LAKES. FURTHER WEST...LOW AMPLITUDE RIDGING IS
POSITIONED OVER THE WEST COAST WITH A WELL- DEFINED TROUGH MOVING
EASTWARD TOWARDS BRITISH COLUMBIA. AT THE SURFACE...HIGH PRESSURE
IS STRETCHED FROM THE SOUTHERN PLAINS TO NEW ENGLAND WITH A
SURFACE LOW OFF THE LOUISIANA COAST IN CONJUNCTION WITH THE TEXAS
UPPER LOW. ANOTHER SURFACE LOW IS OVER NORTHERN ONTARIO IN
CONJUNCTION WITH ONE OF THE WAVES OVER CENTRAL CANADA WITH A
TROUGH AXIS EXTENDING SOUTHWARD ACROSS THE NORTHERN PLAINS.
ABUNDANT BUT THIN CLOUD COVER REMAINS ACROSS THE REGION WITH
SATELLITE SHOWING VERY SLOW EASTWARD MOVEMENT...WITH THE BACK EDGE
STILL ACROSS EASTERN IOWA.
THE CLOUD COVER WILL BE THE MAIN CHALLENGE TODAY. FORECAST SOUNDINGS
SHOW A MIX OF THOUGHTS ON HOW LONG CLOUD COVER WILL HANG ON AND DO
NOT SEE MUCH IMPROVEMENT THROUGH LATE MORNING...THOUGH WESTERN AREAS
HAVE THE BEST CHANCE FOR SCATTERING BY MIDDAY. THE PRESSURE GRADIENT
WILL BEGIN TO TIGHTEN UP AS THE ONTARIO SURFACE LOW MOVES EAST AND
THE ASSOCIATED TROUGH APPROACHES. THIS WILL ALLOW FOR STEADIER
SOUTHWEST WINDS TO DEVELOP. WITH THE IDEA THAT CLOUDS WILL HANG ON
THROUGH THE MORNING THEN SCATTER THIS AFTERNOON...HIGH TEMPS WILL
PROBABLY STRUGGLE DESPITE THE SOUTHWEST WINDS AND MODEST WARM
ADVECTION ALOFT. WILL CONTINUE WITH MID AND UPPER 30S FOR NOW BUT IF
SUN CAN MAKE AN APPEARANCE FOR SEVERAL HOURS THIS AFTERNOON THEN
HIGHS AROUND 40/LOW 40S WOULD BE PLAUSIBLE. A BAND OF MID CLOUDS
WILL ACCOMPANY THE TROUGH PASSAGE EARLY THIS EVENING WITH A FEW
FLURRIES NOT OUT OF THE QUESTION. WINDS TURN NORTHWEST TONIGHT AND
SATURDAY MORNING WITH COOL ADVECTION OCCURRING. CLOUD COVER LOOKS
ABUNDANT SO HIGHS WILL LIKELY BE HELD IN THE MID/UPPER 30S.
MDB
&&
.LONG TERM...
302 AM CST
SATURDAY NIGHT THROUGH MONDAY...ATTENTION TURNS TO THE UPPER TROUGH
OFF THE BRITISH COLUMBIA COAST THIS MORNING. A SHORTWAVE EJECTS FROM
THIS TROUGH AND TRACKS EAST THEN SOUTHEAST AND ACROSS THE LOCAL AREA
EARLY SUNDAY. SURFACE LOW PRESSURE DEVELOPS AND PASSES WITH THE
UPPER TROUGH DURING THE DAY SUNDAY. GUIDANCE CONTINUES TO DISAGREE
ON THE STRENGTH AND TRACK OF THE SYSTEM WITH RECENT RUNS SHOWING
QUITE A BIT OF VARIATION. THESE NORTHWEST SYSTEMS HAVE HAD A
TENDENCY TO TRACK FURTHER SOUTH OR SOUTH AND WEST THAN DEPICTED
AHEAD OF TIME SO WILL NEED TO KEEP A CLOSE EYE ON THE WAVE AS IT
MOVES ONSHORE OVER BRITISH COLUMBIA LATER TONIGHT. AT THIS POINT...A
LOW TRACK ACROSS NORTHWEST OR WEST-CENTRAL ILLINOIS...SIMILAR TO THE
00Z GFS/ECMWF...LOOKS TO BE FAVORED WHEN CONSIDERING THE CURRENT AND
EXPECTED UPPER FLOW PATTERN. WITH WESTERN RIDGING EXPECTED TO
SHARPEN AS MORE PACIFIC ENERGY PUSHES INTO IT FROM THE WEST...THE
FLOW OVER THE ROCKIES/PLAINS WILL TURN MORE NORTHWESTERLY. ONE COULD
MAKE THE CASE THAT IF THE WAVE WERE TO TRACK THROUGH THE CURRENT
UPPER FLOW PATTERN IT WOULD TAKE A TRACK ACROSS THE AREA SO A MORE
NORTHWESTERLY FLOW WOULD SUPPORT A MORE WESTERN TRACK. A TRACK
FURTHER NORTH/EAST SEEMS UNLIKELY BUT WOULD NOT BE SURPRISED TO SEE
IT TRACK WEST OF THE TRACK OF THE 00Z GFS/ECMWF BASED ON THE
ABOVE. GIVEN THE PACIFIC ORIGINS OF THE SYSTEM THERE WILL BE
MOISTURE TO WORK WITH SO PRECIPITATION IS LIKELY WITH IT AND SHOULD
AFFECT MOST OF THE AREA UNLESS A WILD SWING IN THE TRACK OCCURS.
PRECIP TYPE MAY BE MIXED FOR A TIME AT ONSET...MAINLY SOUTH AND WEST
WITH A MORE SOUTH/WEST TRACK LEADING TO MAINLY SNOW FOR MUCH OF THE
AREA. THE 00Z RUN OF THE GFS/ECMWF SUGGEST A MIX EARLY SOUTH AS A
NOSE OF WARM AIR BRIEFLY BUILDS IN BEFORE COLD AIR FILLS IN AGAIN.
BASED ON PRECIPITABLE WATER VALUES AND DURATION OF FORCING THE HEART
OF THE SYSTEM LOOKS TO BE ABLE TO PRODUCE 0.3 TO PERHAPS 0.4 INCHES
OF LIQUID EQUIVALENT PRECIP WITH IT BECOMING A MATTER OF WHERE THE
HEART OF THE SYSTEM TRACKS.
ANOTHER ISSUE WILL BE THE POTENTIAL FOR LAKE ENHANCEMENT AS THE LOW
PASSES SUNDAY AFTERNOON/EVENING. A LOW TRACK TO THE SOUTH AND WEST
OF THE AREA WOULD BE SUPPORTIVE OF LAKE ENHANCEMENT OF SYNOPTIC
PRECIP ON THE BACK SIDE WITH THE COLUMN COLD ENOUGH TO SUPPORT SNOW
IN THIS SCENARIO. HIGH PRESSURE MOVES SOUTHWARD ACROSS ONTARIO INTO
MONDAY WITH ANOTHER SURFACE LOW/ELONGATED TROUGH STRETCHING FROM
MANITOBA TO THE CENTRAL PLAINS WHICH WILL TURN WINDS MORE EASTERLY
THEN SOUTHERLY INTO MONDAY EVENING. WITH FORECAST SOUNDINGS SHOWING
MARGINAL INVERSION HEIGHTS BUT SUFFICIENT DELTA T`S...MAY SEE A
SITUATION SIMILAR TO LAST WEEK WHERE LAKE EFFECT SNOW SHOWERS
PERSISTED IN THE EASTERLY LOW LEVEL FLOW BEFORE ENDING. THIS COULD
BE THE CASE FOR MUCH OF MONDAY. AS FAR AS TEMPS...HIGHS SUNDAY WILL
BE DICTATED BY THE LOW TRACK AND MONDAY LOOKS TO ONLY SEE HIGHS IN
THE 20S THANKS TO COLD ADVECTION.
TUESDAY THROUGH THURSDAY...BROAD RIDGING WEST AND TROUGHING EAST
WILL LEAVE THE LOCAL AREA UNDER A SHARP NORTHERLY UPPER FLOW
TUESDAY WITH HIGH PRESSURE AT THE SURFACE. THE RIDGING WILL
QUICKLY SHIFT EAST AND DE-AMPLIFY WEDNESDAY ALLOWING MILDER AIR TO
RETURN. THE FLOW MAY BE SOMEWHAT ACTIVE BUT PRECIP DETAILS ARE NOT
CLEAR AT THIS RANGE...THOUGH HAVE DECENT CONFIDENCE IN FAIRLY MILD
TEMPERATURES.
MDB
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* MVFR CEILINGS AROUND 1500 FT THROUGH THE AFTERNOON.
* WEST-SOUTHWEST WINDS 220-250 DEG 12-15 KT WITH A FEW HIGHER
GUSTS.
RATZER/BEACHLER
//DISCUSSION...UPDATED 12Z...
AREA OF MVFR CEILINGS AROUND 1500 FT EXTENDS WEST ACROSS THE
MISSISSIPPI INTO EASTERN IOWA. BACK EDGE MAKING SLOW PROGRESS TO
THE EAST...THOUGH EXPECT SOME EROSION AND ACCELERATION OF THIS
DURING THE DAY WITH MVFR CEILINGS DISSIPATING OR MOVING EAST OF
THE TERMINALS BY EARLY THIS AFTERNOON. VFR CONDITIONS EXPECTED
LATER AFTERNOON THROUGH MOST OF TONIGHT...BEFORE SURFACE TROUGH
MOVES THROUGH DURING PRE-DAWN HOURS AND MVFR CIGS RETURN.
WINDS EXPECTED TO REMAIN WEST-SOUTHWEST 220-250 DEGREES THROUGH
THIS EVENING. SUSTAINED SPEEDS EXPECTED GENERALLY 10-15 KT WITH A
FEW HIGHER GUSTS UNDER 20 KTS. WINDS SHIFT WEST-NORTHWEST 290-310
DEG AFTER TROUGH PASSAGE EARLY SATURDAY MORNING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH IN WIND DIRECTION...LOW IN GUST FREQUENCY.
* LOW IN MVFR CEILING DISSIPATION TIME.
RATZER/BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z SUNDAY-12Z FRIDAY...UPDATED 12Z...
SATURDAY NIGHT...SNOW LIKELY AFTER MIDNIGHT. ACCUMULATION LIKELY.
MVFR CIGS AND IFR VIS POSSIBLE.
SUNDAY...SNOW LIKELY. MVFR/IFR LIKELY.
MONDAY...CHANCE OF SNOW SHOWERS. MVFR POSSIBLE.
TUESDAY THROUGH THURSDAY...PRIMARILY VFR.
RATZER
&&
.MARINE...
217 AM CST
MARINE WEATHER CONCERNS INCLUDE SOUTHWESTERLY GALES ACROSS NORTHERN
LAKE MICHIGAN TODAY...THEN A BRIEF PERIOD OF STRONG NORTHEAST-NORTH
WINDS 25-30 KTS OVER CENTRAL/SOUTHERN LAKE MICHIGAN SUNDAY.
A STRONG AREA OF LOW PRESSURE WAS MOVING SLOWLY EAST ACROSS FAR
NORTHERN ONTARIO EARLY THIS MORNING...WHILE A WEST-EAST ORIENTED
RIDGE OF HIGH PRESSURE WAS ACROSS THE MIDWEST REGION SOUTH OF THE
GREAT LAKES. SURFACE PRESSURE FALLS ACROSS ONTARIO AND WESTERN
QUEBEC HAVE TIGHTENED THE GRADIENT ACROSS THE NORTHERN LAKES...AND
WILL REMAIN SO INTO THIS AFTERNOON BEFORE WEAKENING AS THE LOW
REACHES JAMES BAY AND A TRAILING SURFACE TROUGH APPROACHES FROM THE
WEST. SOUTHWEST WINDS HAVE INCREASED WITH A 34 KT GUST NOTED AT PORT
INLAND MI WITHIN THE PAST HOUR...AND A GALE WARNING IS IN EFFECT FOR
THE NORTHERN HALF OR SO OF THE LAKE THROUGH MID-AFTERNOON. WINDS
WILL EASE BELOW GALE FORCE BY LATE AFTERNOON AS THE GRADIENT BEGINS
TO WEAKEN...AND WILL FURTHER DIMINISH TONIGHT.
ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP IN ASSOCIATION
WITH AN ALBERTA-CLIPPER OVER THE WEEKEND...WITH THE LOW DEEPENING
AND MOVING QUICKLY TO NORTHWEST ILLINOIS BY SUNDAY MORNING. WINDS
WILL BECOME NORTHEASTERLY SATURDAY NIGHT AS THE LOW APPROACHES...
AND ARE EXPECTED TO QUICKLY INCREASE TO NEAR 30 KT EARLY IN THE DAY
SUNDAY AS THE LOW MOVES INTO CENTRAL INDIANA. THE PERIOD OF STRONGER
WINDS APPEARS TO BE BRIEF...AS THE LOW BEGINS TO FILL AND RAPIDLY
EXITS THE REGION TO THE SOUTHEAST SUNDAY EVENING AND WEAK HIGH
PRESSURE RIDGING MOVES IN FROM THE NORTHWEST. WEAK HIGH PRESSURE
THEN LOOKS TO LINGER ACROSS THE WESTERN GREAT LAKES INTO EARLY NEXT
WEEK.
FOR THE ILLINOIS AND NORTHWEST INDIANA NEARSHORE WATERS...BREEZY
OFFSHORE WINDS EXPECTED TODAY AND SATURDAY. SMALL CRAFT ADVISORY
CONDITIONS ARE EXPECTED TO DEVELOP QUICKLY SUNDAY MORNING DUE TO THE
STRONG WINDS FROM THE CLIPPER...WITH THE DIMINISHING NORTH FETCH
KEEPING HIGHER WAVES LINGERING INTO EARLY MONDAY.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565 UNTIL 3
PM FRIDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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Area Forecast Discussion
NATIONAL WEATHER SERVICE LINCOLN IL
1000 AM CST Fri Jan 23 2015
.UPDATE...
ISSUED AT 959 AM CST FRI JAN 23 2015
Have updated the forecast to slow the clearing trends and lower
the highs as a result. Clearing line is now just crossing the
Illinois/Iowa border. The latest RAP 925 mb humidity, which
appears to match the clouds fairly well, holds off on any
significant clearing in the northwest CWA until around mid
afternoon and not in the eastern CWA until after sunset. Have gone
with highs in the upper 30s over nearly all the forecast area,
except around 40 in west central Illinois where there is likely to
be some sunshine by mid to late afternoon.
&&
.SHORT TERM...(Today)
ISSUED AT 443 AM CST FRI JAN 23 2015
08z/2am IR satellite imagery shows low clouds blanketing central
Illinois, as moisture remains trapped beneath a subsidence inversion
centered around 900mb. With only very light low-level flow under
prevailing surface high pressure, am not expecting the clouds to
clear out anytime soon. HRRR suggests clouds will remain in place
through the morning, then will slowly begin to clear from west to
east during the afternoon. Based on satellite timing tools, think
clearing will be slightly faster, reaching the Illinois River Valley
by mid to late morning and the I-55 corridor by early afternoon.
The far E/NE KILX CWA around Champaign and Danville will likely
remain overcast through the entire day. High temperatures will
range from the upper 30s across the east where clouds will persist
longest to the lower 40s along/west of I-55 where sunshine will
prevail this afternoon.
&&
.LONG TERM...(Tonight through Thursday)
ISSUED AT 443 AM CST FRI JAN 23 2015
Weak short-wave trough currently evident on water vapor imagery over
southern Manitoba will drop into the Great Lakes tonight. Any light
precip associated with this feature will remain well north of
central Illinois: however, a weak frontal boundary will push through
the area, allowing winds to switch to northwesterly by morning.
Mild and dry conditions will be on tap behind the departing system
for Saturday with high temperatures topping out in the lower to
middle 40s.
Next more significant short-wave is still on target for Sunday, with
good model agreement concerning the strength and track of this
system. Surface low pressure will drop out of Canada on Saturday,
then will track from northeast Iowa Sunday morning to Ohio by Sunday
evening. With this particular track, the heaviest precipitation is
expected to remain further north along/north of the I-80 corridor.
Further south, the precip will be lighter and more scattered in
nature. Based on GFS/ECMWF timing, will introduce low chance PoPs
after midnight Saturday, with higher PoPs across the board during
the day Sunday. Atmospheric profile will remain marginal for snow,
so have only included a rain/snow mix along/north of I-74 Sunday
morning, before precip transitions to all rain by midday. May see a
change to light snow/flurries Sunday night as precip departs and
colder air returns, but no snow accumulation is expected.
After that, another wave will track well north of the area Monday
and Monday night: however, dry conditions are anticipated this far
south. Will be slightly cooler early next week as upper trough
remains in place across the eastern CONUS, resulting in highs in the
30s both Monday and Tuesday. The trough will shift eastward later
in the period, allowing temps to return to the 40s by Wednesday and
Thursday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
ISSUED AT 500 AM CST FRI JAN 23 2015
Back edge of MVFR cigs making slow progress into extreme eastern
Iowa this morning and should push into our western TAF areas
between 16 and 18z. Based on the latest movement, it appears
the clouds won`t push east of CMI until after 22z. Forecast
soundings suggest that once the skies clear, we can expect VFR
conditions thru at least the first half of tonight before a
weak frontal boundary tracks thru the region switching our
flow from southwest to northwest and ushering in another batch
of MVFR cigs for Saturday. Surface flow today will increase out
of the southwest at 10 to 15 kts and then diminish some from the
southwest early this evening before switching into the west and
northwest later tonight with speeds of 10 kts or less.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...Smith
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
109 PM EST FRI JAN 23 2015
.SYNOPSIS...
ISSUED AT 400 AM EST FRI JAN 23 2015
HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY BUT SKIES WILL
REMAIN CLOUDY THIS MORNING BUT A FEW BREAKS IN THE CLOUD COVER
MAY DEVELOP THIS AFTERNOON. HIGH TEMPERATURES TODAY WILL
GENERALLY BE IN THE 30S AND LOWS TONIGHT WILL GENERALLY BE IN THE
20S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EST FRI JAN 23 2015
ANOTHER QUIET SHORT TERM PERIOD WITH CLOUDS AND TEMPS THE ONLY
CONCERN. AS WE SUSPECTED LAST NIGHT...CLOUD COVER REMAINED LOCKED
IN ACROSS THE REGION THIS MORNING UNDERNEATH STRONG INVERSION WITH
WEAK FLOW. CLOUD COVER HAS BEEN EXPANDING NORTHEAST OVERNIGHT WITH
WEAK SOUTHWEST FLOW ALOFT. BACK EDGE OF CLOUD SHIELD CURRENTLY
ACROSS IA INTO MO AND THIS HAS BEEN ADVANCING SLOWLY EAST LAST FEW
HOURS. FORECAST SOUNDINGS VARY DEPENDING ON MODEL CHOICE. WRF
MODELS ALONG WITH HRRR AND RUC GENERALLY SHOW LOW LEVEL MOISTURE
AND INVERSION HANGING TOUGH THROUGH TONIGHT BEFORE CLOUD COVER
WITH NEXT SHORT WAVE ARRIVES. OTHER MODELS SHOW MUCH LESS MOISTURE
BY AFTERNOON SUGGESTING THINNING CLOUD COVER WITH BREAKS. THIS IS
ALWAYS A DILEMMA IN MID WINTER WITH WEAK MIXING AND LOW SUN ANGLE
AND SOMETIMES WE SEE THE CLEARING AND OTHER TIMES WE DO NOT. HAVE
INCREASED CLOUD COVER TODAY OVERALL WITH CLOUDY THIS MORNING BUT
DID TRY AND DEVELOP SOME BREAKS THIS AFTERNOON GIVEN SATELLITE
TRENDS AND 00Z SOUNDINGS SHOWING RELATIVELY THIN MOISTURE DEPTH.
THIS WILL IMPACT TEMPS AS OVERCAST SKIES THROUGH THE DAY WILL ONLY
ALLOW FOR A COUPLE DEGREE RISE WHILE BREAKS WOULD LEAD TO A FEW
MORE DEGREES IN WARMING. MET MOS SEVERAL DEGREES COLDER THAT MAV
AND EC GIVEN ITS PESSIMISTIC OUTPUT. HAVE OPTED TO STAY WITH A
CONSENSUS BLEND IN MIDDLE OF GUIDANCE ENVELOPE.
NEXT SHORT WAVE AND WEAK SURFACE BOUNDARY WILL APPROACH LATE
TONIGHT. NOT EXPECTING MUCH WITH THIS SYSTEM OTHER THAN CLOUDS AND A
VERY LOW CHANCE FOR SNOW SHOWERS NEAR BOUNDARY. THIS SHOULD BE
CONFINED TO EXTREME NORTHERN COUNTIES AND BASICALLY LEFT A SLIGHT
CHANCE POP IN FOR COLLABORATION LATE TONIGHT.
&&
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 401 AM EST FRI JAN 23 2015
MUCH OF THE UPCOMING LONG TERM PERIOD WILL BE CHARACTERIZED BY
PERTURBED NORTHWEST FLOW WITH THE MAIN EVENT TO WATCH STILL ON
SUNDAY. FIRST WAVE WILL SWING THROUGH THE REGION SATURDAY MORNING
AND SEND A WEAK CONVERGENT BOUNDARY ACROSS OUR CWA. A SECONDARY
EMBEDDED VORT MAX WILL THEN PASS OVER OUR AREA DURING THE AFTERNOON
AND MAY TOUCH OFF A FEW ISOLATED RAIN/SNOW SHOWERS. SYNOPTIC FORCING
IS CERTAINLY WEAK BUT FORECAST SOUNDINGS SHOW DECENT LOW LEVEL LAPSE
RATES AND PLENTY OF MOISTURE IN THE LOWEST 5 KFT. THIS RAISES SOME
CONCERN FOR FREEZING DRIZZLE BUT FORECAST SOUNDINGS ALSO SHOW AT
LEAST SOME VARYING DEGREE OF SATURATION ABOVE THE -10C LEVEL AND
SHOULD PROVIDE ENOUGH ICE NUCLEI FOR JUST SNOW. MAY EVEN BE RAIN
DURING THE AFTERNOON GIVEN SURFACE TEMPS IN THE MID TO POSSIBLY
UPPER 30S BUT WITH SURFACE DEWPOINTS HOLDING AT OR BELOW
30...SUSPECT IT WILL MAINLY FALL AS SNOW AND THEN MELT QUICKLY ON
CONTACT WITH THE GROUND. THESE WARM GROUND/SURFACE TEMPS ARE ANOTHER
REASON THAT FREEZING DRIZZLE IS NOT MUCH OF A CONCERN. BEST CHANCES
FOR PRECIP WILL BE ACROSS OUR NORTH WHERE THETA-E FLUX FROM THE
LAKES MAY PROVIDE A MARGINAL BOOST TO HYDROMETEOR PRODUCTION.
MUCH MORE ROBUST PV ANOMALY DIVES INTO THE MIDWEST BY SUNDAY...ON
THE CYCLONICALLY SHEARED SIDE OF LARGELY MERIDIONAL 130 KT UPPER
LEVEL JET. AS HAS BEEN THE CASE FOR MUCH OF THIS WINTER...MODELS
STRUGGLE WITH EXACT TRACK OF SURFACE REFLECTION AND 850MB LOW.
FORECAST IS FURTHER COMPLICATED BY SURFACE TEMPERATURES RIGHT
AROUND THE FREEZING MARK. NOTABLE SOUTHERN ADJUSTMENT SEEN IN MOST
OF THE 00Z GUIDANCE. 00Z GFS...GEM...AND ECMWF NOW TRACK THE SURFACE
LOW SOUTH OF OUR CWA WITH THE ECMWF ACTUALLY GOING THROUGH SOUTHERN
INDIANA. 00Z NAM IS NOW THE NORTHERN OUTLIER. TOUGH TO IGNORE THIS
MORE SOUTH/WEST TREND BUT CONFIDENCE IN ANY PARTICULARS REMAINS LOW
WITH PARENT JET ENERGY STILL OVER THE NORTH PACIFIC. DID RAISE POPS
AND QPF AMOUNTS QUITE A BIT IN OUR SOUTHWEST CWA. ALSO TRENDED
COLDER THOUGH STILL THINK SOME RAIN MAY CUT INTO SNOW TOTALS ACROSS
AT LEAST OUR FAR SOUTHWEST. DYNAMICS WITH THIS SYSTEM ARE NOT OVERLY
IMPRESSIVE BUT SHOULD SEE A DECENT SLUG OF 285K ISENTROPIC ASCENT
AND LOW LEVEL DEFORMATION/FGEN JUST NORTH OF THE SURFACE LOW TRACK.
GOOD MOISTURE FEED TOO...WITH LOW LEVEL MIXING RATIOS AROUND 3 G/KG
AND PWATS UP TO A HALF INCH. COUPLE THIS WITH GOOD MIDLEVEL CVA AND
UPPER LEVEL SUPPORT AND MODEL QPF VALUES OF UP TO 0.4 INCHES MAY NOT
BE TOO FAR OFF. SNOW RATIOS WILL BE ON THE LOW SIDE GIVEN WARM
GROUND AND ELEVATED/SHALLOW DGZ BUT NEVERTHELESS...ADVISORY LEVEL
SNOW COULD EASILY BE POSSIBLE FOR MOST OF OUR CWA BASED ON THE
LATEST 00Z NWP GUIDANCE. WILL GO WITH A CONSERVATIVE 2-4 INCHES FOR
NOW AND SEE WHAT THE 12Z RUNS HAVE TO OFFER.
REST OF THE FORECAST LOOKS FAIRLY BENIGN. RETURN TO COLD TEMPS
EXPECTED FOR THE FIRST HALF OF THE WORK WEEK...ESPECIALLY IF WE GET
A FRESH SNOWPACK. SINGLE DIGIT LOWS AND HIGHS AROUND 20F EXPECTED
FOR A LARGE PART OF THE CWA. POTENTIAL FOR ANOTHER WEAK CLIPPER
SYSTEM ON TUESDAY BUT AIRMASS WILL BE VERY DRY AND FORCING WEAK.
PREFER A SILENT TEN POP FOR NOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1245 PM EST FRI JAN 23 2015
A WEAK RIDGE OF HIGH PRESSURE WAS NORTH OF THE OHIO RIVER...LIKE
AN INACTIVE COL AREA BETWEEN THE DEVELOPING LOW TO THE SOUTH AND
THE APPROACHING SHORTWAVE TROF AND ASSOCIATED SURFACE TROF TO THE
WEST. AIRCRAFT OBSERVATIONS AND EARLY MORNING REGIONAL SOUNDINGS
SHOWED THE INVERSION DEEPENING FROM NORTHEAST TO SOUTHWEST. GIVEN
THIS INVERSION WITH THE COL AREA IN CLOSE PROXIMITY...THE MODELS
APPEAR TO BE CLEARING SKIES AND IMPROVING CONDITIONS TOO FAST...
ESPECIALLY THE GFS. HAVE GONE MORE PESSIMISTIC WITH IMPROVING
CONDITIONS GIVEN ALL OF THESE FACTORS AS BOTH SBN AND FWA OBS
STILL NEAR 015 OVC. THEREFORE... KEPT MVFR AT BOTH SITES FOR THE
ENTIRE TAF PERIOD AT 17Z. TAFS STILL MAY BE TOO OPTIMISTIC WITH
CEILING IMPROVEMENT TO 020...BUT STILL HOPEFUL OF THIS IMPROVEMENT
GIVEN THE 020 MINIMUM FOR FUEL ALTERNATE.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...LASHLEY
SHORT TERM...LASHLEY
LONG TERM...AGD
AVIATION...SKIPPER
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AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1250 PM EST FRI JAN 23 2015
.SYNOPSIS...
ISSUED AT 1250 PM EST FRI JAN 23 2015
HIGH PRESSURE WILL REMAIN OVER THE REGION TODAY BUT SKIES WILL
LIKELY REMAIN CLOUDY BUT A FEW BREAKS IN THE OVERCAST ARE POSSIBLE.
HIGH TEMPERATURES BE IN THE 30S AND LOWS TONIGHT WILL BE IN THE 20S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 401 AM EST FRI JAN 23 2015
ANOTHER QUIET SHORT TERM PERIOD WITH CLOUDS AND TEMPS THE ONLY
CONCERN. AS WE SUSPECTED LAST NIGHT...CLOUD COVER REMAINED LOCKED
IN ACROSS THE REGION THIS MORNING UNDERNEATH STRONG INVERSION WITH
WEAK FLOW. CLOUD COVER HAS BEEN EXPANDING NORTHEAST OVERNIGHT WITH
WEAK SOUTHWEST FLOW ALOFT. BACK EDGE OF CLOUD SHIELD CURRENTLY
ACROSS IA INTO MO AND THIS HAS BEEN ADVANCING SLOWLY EAST LAST FEW
HOURS. FORECAST SOUNDINGS VARY DEPENDING ON MODEL CHOICE. WRF
MODELS ALONG WITH HRRR AND RUC GENERALLY SHOW LOW LEVEL MOISTURE
AND INVERSION HANGING TOUGH THROUGH TONIGHT BEFORE CLOUD COVER
WITH NEXT SHORT WAVE ARRIVES. OTHER MODELS SHOW MUCH LESS MOISTURE
BY AFTERNOON SUGGESTING THINNING CLOUD COVER WITH BREAKS. THIS IS
ALWAYS A DILEMMA IN MID WINTER WITH WEAK MIXING AND LOW SUN ANGLE
AND SOMETIMES WE SEE THE CLEARING AND OTHER TIMES WE DO NOT. HAVE
INCREASED CLOUD COVER TODAY OVERALL WITH CLOUDY THIS MORNING BUT
DID TRY AND DEVELOP SOME BREAKS THIS AFTERNOON GIVEN SATELLITE
TRENDS AND 00Z SOUNDINGS SHOWING RELATIVELY THIN MOISTURE DEPTH.
THIS WILL IMPACT TEMPS AS OVERCAST SKIES THROUGH THE DAY WILL ONLY
ALLOW FOR A COUPLE DEGREE RISE WHILE BREAKS WOULD LEAD TO A FEW
MORE DEGREES IN WARMING. MET MOS SEVERAL DEGREES COLDER THAT MAV
AND EC GIVEN ITS PESSIMISTIC OUTPUT. HAVE OPTED TO STAY WITH A
CONSENSUS BLEND IN MIDDLE OF GUIDANCE ENVELOPE.
NEXT SHORT WAVE AND WEAK SURFACE BOUNDARY WILL APPROACH LATE
TONIGHT. NOT EXPECTING MUCH WITH THIS SYSTEM OTHER THAN CLOUDS AND A
VERY LOW CHANCE FOR SNOW SHOWERS NEAR BOUNDARY. THIS SHOULD BE
CONFINED TO EXTREME NORTHERN COUNTIES AND BASICALLY LEFT A SLIGHT
CHANCE POP IN FOR COLLABORATION LATE TONIGHT.
&&
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 401 AM EST FRI JAN 23 2015
MUCH OF THE UPCOMING LONG TERM PERIOD WILL BE CHARACTERIZED BY
PERTURBED NORTHWEST FLOW WITH THE MAIN EVENT TO WATCH STILL ON
SUNDAY. FIRST WAVE WILL SWING THROUGH THE REGION SATURDAY MORNING
AND SEND A WEAK CONVERGENT BOUNDARY ACROSS OUR CWA. A SECONDARY
EMBEDDED VORT MAX WILL THEN PASS OVER OUR AREA DURING THE AFTERNOON
AND MAY TOUCH OFF A FEW ISOLATED RAIN/SNOW SHOWERS. SYNOPTIC FORCING
IS CERTAINLY WEAK BUT FORECAST SOUNDINGS SHOW DECENT LOW LEVEL LAPSE
RATES AND PLENTY OF MOISTURE IN THE LOWEST 5 KFT. THIS RAISES SOME
CONCERN FOR FREEZING DRIZZLE BUT FORECAST SOUNDINGS ALSO SHOW AT
LEAST SOME VARYING DEGREE OF SATURATION ABOVE THE -10C LEVEL AND
SHOULD PROVIDE ENOUGH ICE NUCLEI FOR JUST SNOW. MAY EVEN BE RAIN
DURING THE AFTERNOON GIVEN SURFACE TEMPS IN THE MID TO POSSIBLY
UPPER 30S BUT WITH SURFACE DEWPOINTS HOLDING AT OR BELOW
30...SUSPECT IT WILL MAINLY FALL AS SNOW AND THEN MELT QUICKLY ON
CONTACT WITH THE GROUND. THESE WARM GROUND/SURFACE TEMPS ARE ANOTHER
REASON THAT FREEZING DRIZZLE IS NOT MUCH OF A CONCERN. BEST CHANCES
FOR PRECIP WILL BE ACROSS OUR NORTH WHERE THETA-E FLUX FROM THE
LAKES MAY PROVIDE A MARGINAL BOOST TO HYDROMETEOR PRODUCTION.
MUCH MORE ROBUST PV ANOMALY DIVES INTO THE MIDWEST BY SUNDAY...ON
THE CYCLONICALLY SHEARED SIDE OF LARGELY MERIDIONAL 130 KT UPPER
LEVEL JET. AS HAS BEEN THE CASE FOR MUCH OF THIS WINTER...MODELS
STRUGGLE WITH EXACT TRACK OF SURFACE REFLECTION AND 850MB LOW.
FORECAST IS FURTHER COMPLICATED BY SURFACE TEMPERATURES RIGHT
AROUND THE FREEZING MARK. NOTABLE SOUTHERN ADJUSTMENT SEEN IN MOST
OF THE 00Z GUIDANCE. 00Z GFS...GEM...AND ECMWF NOW TRACK THE SURFACE
LOW SOUTH OF OUR CWA WITH THE ECMWF ACTUALLY GOING THROUGH SOUTHERN
INDIANA. 00Z NAM IS NOW THE NORTHERN OUTLIER. TOUGH TO IGNORE THIS
MORE SOUTH/WEST TREND BUT CONFIDENCE IN ANY PARTICULARS REMAINS LOW
WITH PARENT JET ENERGY STILL OVER THE NORTH PACIFIC. DID RAISE POPS
AND QPF AMOUNTS QUITE A BIT IN OUR SOUTHWEST CWA. ALSO TRENDED
COLDER THOUGH STILL THINK SOME RAIN MAY CUT INTO SNOW TOTALS ACROSS
AT LEAST OUR FAR SOUTHWEST. DYNAMICS WITH THIS SYSTEM ARE NOT OVERLY
IMPRESSIVE BUT SHOULD SEE A DECENT SLUG OF 285K ISENTROPIC ASCENT
AND LOW LEVEL DEFORMATION/FGEN JUST NORTH OF THE SURFACE LOW TRACK.
GOOD MOISTURE FEED TOO...WITH LOW LEVEL MIXING RATIOS AROUND 3 G/KG
AND PWATS UP TO A HALF INCH. COUPLE THIS WITH GOOD MIDLEVEL CVA AND
UPPER LEVEL SUPPORT AND MODEL QPF VALUES OF UP TO 0.4 INCHES MAY NOT
BE TOO FAR OFF. SNOW RATIOS WILL BE ON THE LOW SIDE GIVEN WARM
GROUND AND ELEVATED/SHALLOW DGZ BUT NEVERTHELESS...ADVISORY LEVEL
SNOW COULD EASILY BE POSSIBLE FOR MOST OF OUR CWA BASED ON THE
LATEST 00Z NWP GUIDANCE. WILL GO WITH A CONSERVATIVE 2-4 INCHES FOR
NOW AND SEE WHAT THE 12Z RUNS HAVE TO OFFER.
REST OF THE FORECAST LOOKS FAIRLY BENIGN. RETURN TO COLD TEMPS
EXPECTED FOR THE FIRST HALF OF THE WORK WEEK...ESPECIALLY IF WE GET
A FRESH SNOWPACK. SINGLE DIGIT LOWS AND HIGHS AROUND 20F EXPECTED
FOR A LARGE PART OF THE CWA. POTENTIAL FOR ANOTHER WEAK CLIPPER
SYSTEM ON TUESDAY BUT AIRMASS WILL BE VERY DRY AND FORCING WEAK.
PREFER A SILENT TEN POP FOR NOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 631 AM EST FRI JAN 23 2015
MVFR CIGS REMAIN THE ISSUE TODAY. SATELLITE SHOWS EXTENSIVE AND
SOLID CLOUD DECK EXTENDING WEST TO NEAR MS RIVER AT 11Z. SLOW
EROSION WAS NOTED WITH CLEARING WORKING SLOWLY EAST. SEVERAL HIRES
MODEL SOUNDINGS INDICATE INVERSION WILL PERSIST AND LOCK LOW LEVEL
MOISTURE IN THROUGH TONIGHT. OTHER GUIDANCE SUGGEST THIN LAYER OF
MOISTURE TO MIX TODAY WITH WEAK FLOW AND SUBSIDENCE. HAVE TRIED TO
BE A BIT OPTIMISTIC WITH CIGS GRADUALLY RISING AND BECOMING BKN
THIS AFTERNOON. BROUGHT FLIGHT CATEGORY UP TO VFR BY EARLY THIS
EVENING ASSUMING BREAKS DO DEVELOP.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MLR
SHORT TERM...LASHLEY
LONG TERM...AGD
AVIATION...LASHLEY
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1132 AM CST FRI JAN 23 2015
.SYNOPSIS...
ISSUED AT 320 AM CST FRI JAN 23 2015
NORTHWEST FLOW WILL CONTINUE THROUGH THE NEXT ONE TO TWO WEEKS. A
SERIES OF WEATHER SYSTEMS WILL MOVE THROUGH THE AREA OVER THE NEXT
SEVERAL DAYS.
&&
.SHORT TERM /TODAY/...
ISSUED AT 320 AM CST FRI JAN 23 2015
A WEAK TROUGH LOOKS TO QUICKLY PUSH THROUGH THE STATE LATE
THIS MORNING AND INTO THE AFTERNOON. THERE IS SOME WEAK 700-500MB
THETA-E ADVECTION AND MID-LEVEL FORCING WITH THIS CLIPPER...BUT
TREMENDOUS AMOUNT OF DRY AIR BELOW 700MB TO THE SURFACE WILL MAKE
IT DIFFICULT FOR ANY PRECIP FALLING THROUGH THIS LAYER TO REACH
THE GROUND. LOWERED POPS AND HAVE ONLY SPRINKLES MENTIONED WITH
THE LOWER CONFIDENCE OF MEASURABLE PRECIP. THE 23.03Z HOPWRF AND
LATEST HRRR HAVE A GOOD HANDLE OF THE VERY LIGHT
PRECIP/REFLECTIVITY TRENDS LATE THIS MORNING INTO THE EARLY
AFTERNOON OVER NORTHERN IOWA.
DECENT WAA AHEAD OF THE WEAK TROUGH TODAY AND WENT WELL ABOVE
GUIDANCE OVER THE CENTRAL TO SOUTH. THE RUC13 HAS A VERY GOOD
HANDLE ON THE MAX TEMPS TREND TODAY AND LEANED TOWARDS THE
23.07Z RUN. THE CLOUD COVER MOVING IN WITH THE SHORTWAVE IS THE
CAVEAT...THE QUESTION REMAINS IF CLOUD DECK WILL MOVE IN QUICK
ENOUGH TO HOLD TEMPS DOWN. LEANED TOWARD THE WAA AND ENOUGH
SUNSHINE EARLY ON IN THE DAY TO PUT TEMPS WELL INTO THE 40S...AND
THUS TWEAKED UP MAX TEMPS OVER THE SOUTHERN HALF OF THE FORECAST.
.LONG TERM /TONIGHT THROUGH THURSDAY/...
ISSUED AT 320 AM CST FRI JAN 23 2015
TROUGH OF LOW PRESSURE FROM NWRN MN INTO CO WILL MOVE THROUGH THE
AREAS TODAY. SWLY FLOW WILL BRING WARMER AIR TO THE STATE TODAY.
THE COOLING WILL BE SHORT LIVED AS THE NEXT WEATHER DISTURBANCE
WILL MOVE THROUGH SUNDAY INTO SUNDAY EVENING. SOME DISCREPANCY
WITH THE TRACK...HOW FAR SOUTHWEST...ON IT. THE ECMWF IS AMONG THE
FARTHEST WEST...BUT EVEN SO THE TRACK IS FAR ENOUGH TO THE
NORTHEAST THAT MUCH OF IA WILL BE IN THE RAIN AREA...OR REMAIN
DRY WITH ANY FROZEN PRECIP OVER THE FAR NORTHEAST.
A STRONGER SYSTEM WILL MOVE THROUGH MID WEEK. A STRONG PUSH OF
WARM AIR IS EXPECTED AHEAD OF THIS SYSTEM AND WENT WELL ABOVE MOS
FOR HIGHS ON WED. ONCE THE SYSTEM PASSES...A TRANSITION IN THE
PATTERN WILL BEGIN. THE STORM TRACK WILL SHIFT FARTHER TO THE WEST
AND ARCTIC AIR WILL BEGIN TO SPILL INTO THE CENTRAL U.S.
&&
.AVIATION...23/18Z
ISSUED AT 1132 AM CST FRI JAN 23 2015
OVERNIGHT A STRATUS DECK COULD DEVELOP AND MOVING INTO THE
AREA...BUT CONFIDENCE IS RELATIVELY LOW. SATELLITE IMAGERY DEPICTS
SUCH CLOUDS APPROACHING FROM NORTHERN MN BUT ON A TRAJECTORY TO
JUST CLIP NORTHEAST IA. ALL MODEL GUIDANCE INDICATES DEVELOPMENT
OF LOW CLOUDS OVER EASTERN SD AND WESTERN MN TODAY...APPARENTLY
THOSE THAT WOULD FOLLOW THE STEERING FLOW DOWN INTO CENTRAL IOWA
TONIGHT...BUT CURRENTLY SATELLITE AND OBSERVATIONS SHOW CLEAR
SKIES OVER THOSE AREAS. SUSPECT THAT THE MODELS POOR HANDLE ON
CURRENT SNOW COVER MAY BE LEADING TO OVERZEALOUS PREDICTIONS OF
NEAR SURFACE MOISTURE AND CLOUD DEVELOPMENT. HOWEVER...WITH MVFR
CIGS ALREADY IN THE TAFS HAVE MAINTAINED THEM AND WILL WATCH
OBSERVATIONAL TRENDS TO OUR NORTHWEST THIS AFTERNOON AND TONIGHT.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...MS JAN 15
SHORT TERM...PODRAZIK
LONG TERM...MS JAN 15
AVIATION...LEE
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1033 AM CST FRI JAN 23 2015
.DISCUSSION...
KSHV RADAR CONTINUES TO SHOW PATCHY AREAS OF LIGHT RAIN AND
DRIZZLE...POSSIBLY MIXED WITH A FEW SLEET PELLETS/SNOW GRAINS.
THIS IS EXPECTED FOR MUCH OF THE DAY...AS A POSITIVELY TILTED
UPPER TROF MOVES ACROSS TX. WE SHOULD SEE THIS PRECIP TAPER OFF
TODAY...AS THE TROF CONTINUES EWD AND THE MOISTURE SUPPLY BECOMES
CUT OFF. FOR THE UPDATE...THE GRIDS ARE IN GOOD SHAPE FOR THE MOST
PART. HAVE TWEAKED THE SKY GRIDS TO ACCOUNT FOR THE PATCHY
CLEARING ACROSS OUR NWRN AREAS. OTHERWISE...NO OTHER CHANGES ARE
EXPECTED ATTM. /12/
&&
.PREV DISCUSSION... /ISSUED 539 AM CST FRI JAN 23 2015/
AVIATION...
IFR/LIFR CEILINGS WITH -RA TO PERSIST ACROSS AREA TERMINALS
THROUGH 23/18Z WITH GRADUAL IMPROVEMENT TO VFR FROM THE WEST
THROUGH 24/00Z. OTHERWISE...NORTHWEST WINDS 10 KNOTS WITH HIGHER
GUSTS TO GRADUALLY DIMINISH THROUGHOUT THE DAY...BECOMING WEST AT
5 KNOTS OVERNIGHT. /05/
PREV DISCUSSION... /ISSUED 416 AM CST FRI JAN 23 2015/
DISCUSSION...
COLD CORE UPPER TROUGH IS WELL WEST OF THE AREA BUT IT SHOULD MOVE
ACROSS THE CWA THIS EVENING/TONIGHT. DRY SLOTTING IS ALREADY
OCCURRING AND THE MANY OF THE MODELS HAVE NOT HANDLED IT VERY WELL.
THE HRRR SEEMS TO HAVE THE BEST HANDLE ON THE PRECIP KEEPING THE
VAST MAJORITY OF IT SE OF A KJSO-KELD LINE. THIS IS SUPPORTED BY
THE LATEST RADAR IMAGES WHICH SHOW THE NEXT ROUND OF RAIN ALONG
THE I-10 CORRIDOR HEADING NEWD TOWARDS THE AREA. SCATTERED AREAS
OF LIGHT RAIN ARE ONGOING THIS MORNING AND WILL LIKELY PERSIST AS
FAR NORTH AS I-30 AS DRIER AIR SLOWLY WORKS IN FROM THE NORTH.
MOST OF THE ATMOSPHERE IS BELOW FREEZING WITH THE EXCEPTION OF THE
LOWEST 2000 FEET OR SO AND SFC TEMPS ARE STILL AROUND 40 DEGREES F.
ANY SNOW THAT MAY BE FALLING WILL MOST LIKELY MELT IN THIS LOWEST
LAYER PRIOR TO REACHING THE SFC. LATEST OBS ARE SHOWING SOME
LOCATIONS IN E TX HAVE COOLED INTO THE MID 30S. THEREFORE...A FEW
FLURRIES CANNOT BE COMPLETELY RULED OUT THIS MORNING...MAINLY
NORTH OF A LINE FROM TYLER AND MARSHALL TX TO MAGNOLIA AR...BUT WITH
SFC TEMPERATURES REMAINING ABOVE FREEZING NO ACCUMULATIONS AND NO
IMPACTS ARE ANTICIPATED. ANY WINTRY PRECIP WILL TRANSITION BACK TO
ALL LIQUID RAIN LATER THIS MORNING AND THE PRECIP SHOULD MOVE EAST
AND OUT OF THE CWA THIS EVENING.
CLEARING SKIES TONIGHT COMBINED WITH COLD AND DRY AIR SHOULD
ALLOW FOR A CHILLY NIGHT TONIGHT/SATURDAY MORNING. OVERNIGHT LOWS
ALONG AND NORTH OF I-20 WILL LIKELY BE NEAR OR BELOW FREEZING. WLY
WINDS AND ABUNDANT SUNSHINE SHOULD LEAD TO A QUICK WARMING TREND
WITH DAYTIME HIGHS ABOVE 60 DEGREES AREAWIDE. NWLY FLOW ALOFT WILL
BRING THE NEXT COLD FRONT INTO THE AREA LATE MONDAY/EARLY TUESDAY.
HARDLY ANY COLD AIR ADVECTION IS EXPECTED WITH THE FRONT SO THE
ONLY REAL EFFECT ON TEMPS WILL BE TO HALT THE WARMING TREND AND
GENERALLY HOLD DAYTIME HIGHS IN THE 60S.
AN UPPER RIDGE WILL BUILD OVER THE REGION KEEPING A PERSISTENCE
FCST IN PLACE FOR MUCH OF NEXT WEEK WITH WARM AND DRY CONDITIONS
EXPECTED. THE RIDGE WILL MOVE EAST LATE NEXT WEEK AND OUR NEXT
RAIN CHANCES WILL LIKELY BE NEXT FRIDAY AND INTO THE WEEKEND AS
THE FLOW ALOFT TRANSITION BACK TO NWLY AND A COLD FRONT MOVES INTO
THE CWA AND BECOMES STATIONARY. /09/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 44 32 57 37 65 / 50 10 0 0 0
MLU 43 32 57 37 64 / 50 30 0 0 0
DEQ 48 28 57 33 62 / 20 0 0 0 0
TXK 46 31 56 36 63 / 40 10 0 0 0
ELD 43 31 57 36 62 / 50 20 0 0 0
TYR 47 33 57 37 65 / 40 10 0 0 0
GGG 45 32 57 36 65 / 40 10 0 0 0
LFK 45 35 59 37 65 / 50 10 0 0 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
12
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1205 PM CST FRI JAN 23 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 421 AM CST FRI JAN 23 2015
SHORT TERM CONCERN REMAINS THE THREAT OF FREEZING RAIN/SLEET MOVING
ACROSS THE NORTHERN AND EASTERN CWA MAINLY THROUGH THIS MORNING.
CURRENT RADAR TRENDS INDICATE MODELS MAY BE DOWNPLAYING EXTENT OF
FREEZING RAIN THREAT. WILL FOLLOW A COMBO RAP ISENTROPIC
ANALYSIS (290K/295K LAYERS) AND HRRR TREND FOR POPS THIS AM.
STILL LOOKS THE BEST THREAT REMAINS ALONG AND NORTH OF THE I94
CORRIDOR. WILL LET THE ADV EXPIRE TO THE FAR WEST THROUGH 15Z AND
IN THE EAST BY 18Z. ROAD TEMPERATURE ARE CURRENTLY AROUND 30F IN
THE NORTHERN CWA AND COOLER INTO THE SOUTHERN PORTION OF THE AREA.
SURFACE DEWPTS ARE IN THE LOWER 20S TO THE SOUTH WILL BOTH HELP
AND HINDER FREEZING RAIN THREAT. MAY TAKE SOME TIME TO SATURATE
THE FARTHER SOUTH THE AREA OF PRECIPITATION MOVES THIS MORNING. IF
IT DOES PRECIPITATE...SOME COOLING FROM THE DRIER AIR WILL ENHANCE
THE FREEZING RAIN THREAT ON UNTREATED ROADS/BRIDGES.
TEMPERATURES SHOULD WARM ABOVE FREEZING THROUGH NOON MOST AREAS
ENDING THE FREEZING RAIN THREAT. THIS SYSTEM EXITS TO THE EAST BY
THIS EVENING WITH CLOUDS REMAINING THROUGH THE NIGHT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 421 AM CST FRI JAN 23 2015
THE LONG TERM BEGINS SATURDAY TRANQUIL AROUND HERE...BUT A STRONG
NOR EASTER WILL BE PUSHING UP THE EAST COAST WHILE A RIDGE BUILDS
UP THE WEST COAST. BOTH WILL IMPACT THE CLIPPER SET TO DIVE INTO
THE UPPER MIDWEST SATURDAY NIGHT. MODELS HAVE TRENDED SHARPER WITH
THE WAVE WHICH RESULTS IN A WESTWARD SHIFT SIMILAR TO WHAT WAS
SEEN WEDNESDAY NIGHT. GIVEN THE SYNOPTIC SET UP...THIS IS THE
PREFERRED TREND. 00Z NAM WAS FLATTEST AND MUCH FURTHER EAST THAN
THE REST OF THE GUIDANCE AND WAS IGNORED. THE GFS/CANADIAN SEEM
LIKE THE BEST COMPROMISE WITH THE ECMWF A BIT TOO FAST AND
CONSIDERABLY LIGHTER WITH ITS PRECIP. 06Z NAM HAS TRENDED FURTHER
WEST CLOSER TO THE 00Z GFS AND CANADIAN. AT THIS STAGE...IT IS
UNLIKELY THE TRACK WILL SHIFT SIGNIFICANTLY EAST...BUT IT COULD
STILL TREND SLIGHTLY WEST.
THE TRACK OF THE LOW WILL PLAY A SIGNIFICANT ROLE IN WHO SEES THE
MOST ACCUMULATION. A GOOD BAND OF SNOW WILL SET UP ALONG AND JUST
EAST OF THE LOW...WITH SOME POTENTIAL FOR DRY SLOTTING ON THE WEST
SIDE. IT WILL BE A QUICK MOVER...SO ONLY EXPECTING ABOUT 6-9 HOURS
OF ACCUMULATING SNOWFALL. A GENERAL 2-4 INCHES APPEAR LIKELY
WITHIN THE HEART OF THE BAND WITH AMOUNTS GRADUALLY TAPERING OFF
TO THE EAST AND QUICKLY TAPERING OFF TO THE WEST. CURRENTLY...THE
HEAVIEST AXIS OF SNOW IS FORECAST TO SET UP FROM NORTHWEST MN TO
EAST CENTRAL MN AND SOUTHWEST WI. FLURRIES MAY PERSIST INTO
SUNDAY MORNING BUT A SURFACE RIDGE AXIS WILL BUILD IN SUNDAY
AFTERNOON.
ANOTHER CLIPPER WILL BRING A BAND OF LIGHT SNOW ACROSS MN SUNDAY
NIGHT AND INTO WISCONSIN BY MONDAY. THIS WILL BE A SLOWER MOVER
SINCE THE FIRST CLIPPER WILL BE DEVELOPING OFF THE EAST COAST. A
PROLONGED PERIOD OF LIGHT SNOW OR FLURRIES COULD DEVELOP OVER THE
EASTERN AREAS DURING THIS TIME. ACCUMULATIONS WILL BE LIGHTER THAN
WITH THE FIRST SYSTEM.
A PATTERN SHIFT WILL TAKE PLACE TUESDAY AND WEDNESDAY WITH THE
RIDGE BUCKLING TO THE NORTHEAST. A SHOT OF WARMTH WILL SURGE INTO
THE UPPER MIDWEST THANKS TO A 50+ KT 850 MB JET BRINGING +10 TO
+13C AIR IN. GUIDANCE IS WAY TOO COLD IN SUCH A PATTERN...AND
NUDGED TEMPS UP SEVERAL DEGREES. MAY CRACK 50+ ACROSS WRN MN AND
MID TO POSSIBLY UPPER 40S FURTHER EAST.
COLD FRONT WILL DROP SOUTH FOR LATE WEEK AS THE PATTERN SHIFTS
TOWARD SOMETHING MORE COMMON DURING THE LAST YEAR. LUCKILY FOR
US...THE COLDEST SURGE OF ARCTIC AIR WILL ROTATE EAST INTO NEW
ENGLAND AND GIVE US A GLANCING BLOW. EVEN WITH THIS...TEMPS WILL
STILL REMAIN NEAR AVERAGE THURSDAY AND FRIDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1147 AM CST FRI JAN 23 2015
QUIET STARTING OUT THIS AFTERNOON WITH WIDESPREAD VFR CONDITIONS.
TROUGH AXIS ORIENTED SW TO NE THROUGH CENTRAL MN AT THIS TIME WILL
CONTINUE PUSHING SE THROUGH THE DAY. A SIMILARLY ORIENTED BAND OF
MID CLOUDS CONTINUES PUSHING SOUTHEAST AHEAD OF THE TROUGH AXIS.
LIGHT FREEZING RAIN HAD FALLEN OUT OF THESE CLOUDS THIS
MORNING...BUT LOW LEVEL DRYING CONTINUES PREVENTING MUCH OF
ANYTHING FROM REACHING THE GROUND. MOST OF THE CWA WILL SEE CLEAR
SKIES FOR MUCH OF THE AFTERNOON...BEFORE A SOLID DECK OF STRATUS
CURRENTLY IN NORTHERN MN MOVES INTO CENTRAL MN BY LATE AFTERNOON
AND PROGRESSES TOWARD THE IOWA BORDER THROUGH THE EVENING. LIGHTER
WINDS AND A MELTING SNOW PACK SUGGEST THE DECK EXPANDING AND
LOWERING OVERNIGHT...WITH SOME FOG A POSSIBILITY.
KMSP...LOW LEVEL DRYING HAS MADE FOR A MORE OPTIMISTIC FORECAST
THIS AFTERNOON...WITH CLEAR SKIES HOLDING TRUE UNTIL THE STRATUS
ABRUPTLY ARRIVES AROUND 5-6PM. CIGS WILL NOT GRADUALLY GO
DOWN...BUT INSTEAD WE`LL HAVE CLEAR SKIES SUDDENLY BECOME OVERCAST
WHEN THE STRATUS DECK ARRIVES.
/OUTLOOK FOR KMSP/
SATURDAY NIGHT...BECOMING MVFR. CHC IFR CIGS/VSBYS -SN MAINLY
AFTER 06Z SUN. 1-3" OF ACCUMULATION POSSIBLE. WIND W 5-10 KTS.
SUNDAY...MVFR WITH -SN/IFR POSSIBLE. WIND NW 10G20 KTS.
MONDAY...VFR. WIND SW 5-10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR MNZ044-045-052-
053.
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ014>016-023-
025-027.
&&
$$
SHORT TERM...DWE
LONG TERM...BORGHOFF
AVIATION...SPD
AREA FORECAST DISCUSSION
NWS JACKSON MS
1040 AM CST FRI JAN 23 2015
.UPDATE...SURFACE ANALYSIS HAD THE LOW JUST SOUTH OF THE FLORIDA
PANHANDLE. THE BACK EDGE OF THE MAIN RAIN SHIELD HAS SHIFTED
SOUTHEAST OF OUR CWA AND WL CONTINUE TO SHIFT FARTHER EAST AS THE
SURFACE LOW LIFTS NORTHEAST THIS AFTERNOON. HOWEVER...LIGHT RAIN AND
LIGHT DRIZZLE WILL CONTINUE OVER OUR CWA AHEAD OF AN APPROACHING
UPPER LEVEL TROUGH THAT WAS NOTED OVER THE SOUTHERN PLAINS THIS
MORNING. WITH THE GUSTY NORTH WIND BENEATH OVERCAST SKIES AND LIGHT
PRECIPITATION THIS AFTERNOON...TEMPERATURES WILL STRUGGLE TO WARM
AND REMAIN NEARLY STATIONARY UNTIL THIS EVENING. TEMPERATURES WILL
RUN IN THE UPPER 30S TO LOWER 40S AT MOST LOCATIONS. POPS ACROSS THE
SOUTHEAST WERE LOWERED WITH THE UPDATE BUT TEMPERATURES WERE ON
TRACK. /22/
&&
.AVIATION...IFR CONDITIONS WILL PREVAIL THROUGH MUCH OF THE DAY WITH
CONTINUED -RA DURING THE DAYTIME HOURS. CEILINGS/VISBYS WILL BEGIN
TO IMPROVE IN THE NORTH TONIGHT...REACHING VFR AT SITES LIKE GLH AND
GWO BY AROUND OR SHORTLY AFTER MIDNIGHT. FARTHER SOUTH CONDITIONS
WILL BE SLOWER TO IMPROVE...REACHING MVFR BY DAYBREAK. HOWEVER MVFR
CEILINGS MAY PERSIST INTO THE MORNING SATURDAY. PRECIP WILL END FROM
WEST TO EAST AROUND MIDNIGHT TONIGHT. PRECIP MAY MIX WITH OR CHANGE
OVER TO -SN AFTER 00Z MAINLY AT NORTHERN TAF SITES...GLH GWO AND
GTR...HOWEVER NO NOTABLE ISSUES ARE EXPECTED AT THE SURFACE. /DL/
&&
.PREV DISCUSSION... /ISSUED 328 AM CST FRI JAN 23 2015/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT...STRONG DEEP LAYERED
WARM ADVECTION HAS BEEN RESPONSIBLE OVERNIGHT FOR THE WIDESPREAD
MODERATE TO AT TIMES HEAVY RAIN OVER THE CWA. CURRENT RADAR TRENDS
AND MODEL DATA IN AGREEMENT THAT THE DEEP LAYERED ASCENT WILL SHIFT
EAST TODAY LEAVING BEHIND A RAW...CLOUDY...DRIZZLY DAY FOR THE CWA.
EVEN THOUGH THE AREA IS BEING DRY SLOTTED IN ADVANCE OF THE MID/UPPER
LEVEL COLD CORE...BELIEVE BOUNDARY LAYER COOLING WILL MAINTAIN CLOUD
COVER AND PERIODS OF LIGHT RAIN/DRIZZLE. HRRR OUTPUT IS SHOWING THE
MAJORITY OF THE PRECIP CLEAR OUT OVER THE SE TWO THIRDS...BUT
MAINTAINS A NEAR STEADY BAND OF LIGHT RAIN OVER NW SECTIONS IN CLOSE
PROXIMITY TO THE DEFORMATION ZONE.
AS THE MID/UPPER LEVEL COLD CORE MOVES THROUGH TONIGHT...DEEP
LAYERED COOLING WILL ALLOW FOR RISING THETA SURFACE AND MORE LIGHT
PRECIPITATION. BUFR SOUNDINGS CONTINUE TO SHOW SOME POSSIBILITY OF
LIGHT SNOW MIXING IN WITH THE LIGHT RAIN ALONG THE HIGHWAY 82
CORRIDOR BEFORE ALL THE PRECIPITATION COMES TO AN END AFTER MIDNIGHT.
CLOUDS CLEARING OUT DURING THE MORNING SATURDAY WILL GIVE WAY TO
SUNNY SKIES BY AFTERNOON. MAX TEMPS SHOULD BE MAKE IT INTO THE LOW TO
MID 50S./26/
LONG TERM...SUNDAY THROUGH NEXT WORK WEEK...PRONOUNCED NORTHWEST
FLOW ALOFT WILL EXIST OVER THE REGION SUNDAY THROUGH WEDNESDAY OF
NEXT WEEK...UPSTREAM OF A LONGWAVE TROUGH CENTERED NEAR THE EAST
COAST. THIS PATTERN WILL PROMOTE A FEW CONTINENTAL COLD AIR SURGES
MAINLY EAST OF THE MS RIVER THROUGH THIS TIME...WITH ANY REAL
CHANCES OF PRECIP ASSOCIATED WITH THESE SURGES (AND MOST OF THE
CLOUDS) CONFINED WELL TO OUR NORTH AND EAST. THE GENERAL PATTERN
SUGGESTS 3 TO 4 DAYS OF EFFICIENT DAYTIME MIXING (AND THEREFORE
WARMING) WITH NIGHTS CAPABLE OF GOOD RADIATIONAL COOLING. BLENDED
GUIDANCE TEMPERATURES WERE MAINLY ON THE WARM SIDE OF AVERAGE
(ESPECIALLY ACROSS SOUTHWESTERN ZONES) AND DEVIATIONS FROM THE MAIN
BLEND WERE NOT MAJOR. HOWEVER...I DID TEND TO FOLLOW LATEST
OPERATIONAL EURO IDEA OF TIMING OF COOL AIR SURGES SUNDAY NIGHT AND
AGAIN AROUND TUESDAY NIGHT...AND SUBTLY TRENDING GUIDANCE COOLER (OR
WARMER) BASED ON THE UNDETAILED BLEND. ALL IN ALL...THIS SHOULD BE
DECENT PERIOD OF WEATHER FOR THE REGION CONSIDERING THE CALENDAR
DATE.
BY LATE IN THE WORK WEEK SOUTHERN STREAM ENERGY WILL START MAKING
INROADS TOWARD THE REGION...INCREASING CLOUDS AND GRADUALLY
INCREASING RAIN CHANCES. THE TYPICALLY-SOLID EUROPEAN OPERATIONAL
MODEL STILL IS INSISTENT ON CUTTING OFF A BIG PIECE OF THIS SOUTHERN
STREAM ENERGY NEAR BAJA CALIFORNIA...WHICH WOULD HAVE THE EFFECT OF
CONFINING INCLEMENT WEATHER MOSTLY WEST OF OUR REGION.
HOWEVER...CONSENSUS OF OTHER LONG RANGE MODELS TENDS TO PHASE THIS
ENERGY WITH THIS NORTHERN STREAM...WHICH WOULD ENSURE MUCH MORE
IMPACT IN OUR REGION. THE LATTER CONSENSUS ALSO TENDS TO SUGGESTS
ARRIVAL OF PRECIP COULD COINCIDE WITH A LARGER COLD AIR SURGE INTO
THE SOUTH...AND THAT IS OF COURSE AN INTERESTING PROSPECT. BUT ANY
MEANINGFUL JUXTAPOSITION OF THOSE TWO ELEMENTS WOULD BE BEYOND THE
CURRENT LONG TERM PERIOD SO WE HAVE SOME MORE TIME TO LET MODEL
INCONGRUITIES LESSEN. /BB/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 43 34 53 34 / 53 73 8 2
MERIDIAN 46 35 52 31 / 54 70 10 3
VICKSBURG 42 33 54 36 / 73 66 6 2
HATTIESBURG 48 36 55 34 / 54 51 8 2
NATCHEZ 43 34 55 36 / 68 56 7 2
GREENVILLE 41 32 53 35 / 89 51 6 2
GREENWOOD 41 31 53 34 / 81 65 7 2
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
22/DL/26/BB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
235 PM EST FRI JAN 23 2015
.SYNOPSIS...A LOW PRESSURE SYSTEM WILL TRACK NORTHEAST OVER THE
EASTERN CAROLINA`S TONIGHT AND EARLY SATURDAY. THE MAIN COLD FRONT
WILL PUSH THROUGH OUR REGION SATURDAY. ANOTHER COLD FRONT WILL
APPROACH FROM THE NORTHWEST SUNDAY NIGHT AND EARLY MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 PM FRIDAY...
COLD RAINY WEATHER TONIGHT INTO EARLY SATURDAY...
SURFACE HIGH PRESSURE CONTINUED TO RETREAT OFFSHORE THIS AFTERNOON
AS LOW PRESSURE TRACKED ALONG THE GULF COAST STATES. RAIN BECAME
WIDESPREAD ACROSS THE CAROLINA`S TODAY WITH SOME AREAS REPORTING A
BRIEF MIXTURE OF SLEET AND RAIN AT THE PRECIPIATION ONSET FROM THE
TRIAD TO ROXBORO. THE HIGH TO THE NORTH WAS RETREATING RAPIDLY
OFFSHORE THIS MORNING WHICH QUICKLY CUT OFF ANY SOURCE OF COLD AIR
INTO OUR REGION. INSTEAD... A SOUTHEAST TO SOUTH FLOW INCREASED JUST
ABOVE THE SURFACE WITH RAPIDLY MOISTENING AND WARMING COLUMN OUT IN
ADVANCE OF THE APPROACHING DEEP MID/UPPER TROUGH OVER THE LOWER
MISSISSIPPI VALLEY. AS THIS TROUGH APPROACHES... THEN CROSSES OVER
THE REGION TONIGHT... THE SURFACE LOW CURRENTLY DEVELOPING OVER THE
FLORIDA PANHANDLE WILL TURN NORTHEAST ALONG THE COASTAL PLAIN OF
GA/SC/NC OVERNIGHT. WITH SURFACE TEMPERATURES SAFELY ABOVE FREEZING
AND WITH SATURATION IN PLACE AT THE SURFACE... AND EVEN CONTINUED
WARMING ALOFT... PLAIN RAIN WILL CONTINUE TO BE DOMINATE OVER NC.
THE TEMPERATURES SHOULD BE NEAR THE LOWS ALREADY THIS AFTERNOON (IN
THE MID 30S)... WITH READINGS EXPECTED TO REMAIN STEADY OR SLOWLY
RISE (ESPECIALLY ALONG I-95 OVERNIGHT). THE RELATIVELY FAST MOVEMENT
OF THE LOW PRESSURE (REACHING NEAR ELIZABETH CITY BY 09Z/SAT) SHOULD
COMBINE WITH THE STRONG IN-SITU COLD AIR DAMMING EVENT OVER THE
PIEDMONT TO LIMIT THE WESTWARD OR INLAND PUSH OF THE COASTAL FRONT.
TEMPS OVER THE COASTAL PLAIN MAY WELL RISE TO AROUND 50 LATE
TONIGHT... WHILE READINGS REMAIN IN THE MID 30S OVER THE NW
PIEDMONT.
QPF MAY BE A BIT LESS THAN EARLIER ANTICIPATED AS THE DEEP
CONVECTION CONTINUES TO BE ROLLING ALONG FROM THE GULF TO FLORIDA...
HAVING SOME NEGATIVE IMPACT ON QPF INLAND. JUST HOW MUCH THIS
AFFECTS OUR STORM TOTALS IS OF LOW CONFIDENCE. THE LATEST HRRR AND
THE OPERATIONAL MODELS GENERALLY DEPICT ABOUT 1/3 LESS QPF THAN THE
EARLIER 1-2 INCH FORECAST. WE WILL TREND A BIT LOWER - WHICH WOULD
LESSEN THE RUNOFF POTENTIAL FOR OUR REGION - WHICH WAS NOT
ANTICIPATED TO CREATE MAJOR PROBLEMS EVEN WITH 1-2 INCHES STORM
TOTALS. THE HRRR... WHICH ACTUALLY VERIFIED WELL WITH P-TYPE AND
TIMING TODAY... INDICATES THE MAIN BACK EDGE OF THE LARGE RAIN
SHIELD MAY EDGE INTO THE SW PIEDMONT BY AT LEAST 06Z AND THE REST OF
THE REGION BY 12Z/SAT. HOWEVER... THERE MAY BE ADDITIONAL "FILL IN"
OF ANY DRY HOLES INLAND SC/NC IF/WHEN THE DEEP SOUTH/FLORIDA
CONVECTION DISSIPATES. THE THUNDERSTORM THREAT IS MINIMAL OVER OUR
REGION GIVEN THE TRACK OF THE LOW AROUND OR JUST EAST OF I-95... AS
MOST OF THE REGION WILL REMAIN IN THE CAD REGION. THE HEAVIEST QPF
AROUND 1 TO 1.5 INCHES IS STILL FORECAST OVER AND EAST OF THE
TRIANGLE... WITH AMOUNTS LIKELY 0.50 TO 0.75 IN THE NW. -BADGETT
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
AS OF 230 PM FRIDAY...
THE MAIN RAIN EVENT WILL END BETWEEN 09Z/15Z SW TO NE ACROSS OUR
REGION SATURDAY AS THE STORM BOMBS AS IT MOVES AWAY FROM DELMARVA.
THE TRAILING DEFORMATION BAND OF PRECIPITATION WITH THE MID LEVEL
LOW IS EXPECTED TO WEAKEN AND DISSIPATE AS IT SPREADS EAST FROM
KY/TN/WVA INTO WESTERN VA AND NORTH-CENTRAL NC SATURDAY. IN
ADDITION... THE BOUNDARY LAYER WINDS WILL SHIFT TO THE WNW AND
INCREASE TO 10-20 MPH IN DOWNSLOPE FASHION DURING THE AFTERNOON.
THIS SHOULD LEAD TO SHARP CLEARING FROM OFF THE BLUE RIDGE INTO THE
PIEDMONT DURING THE AFTERNOON. SKIES SHOULD BECOME PARTLY SUNNY DOWN
EAST LATE IN THE AFTERNOON. HIGHS SHOULD RETURN INTO THE 45-55 RANGE
NW TO SE. THE SKIES SHOULD REMAIN MOSTLY CLEAR TO PARTLY CLOUDY
SATURDAY NIGHT. LOWS 30-35 WITH DIMINISHING NW BREEZES IN THE
EVENING.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
AS OF 235 PM FRIDAY...
SUNDAY: FAIR WEATHER EXPECTED DURING THE DAYTIME HOURS SUNDAY WITH A
FLAT RIDGE OVER OUR AREA...BETWEEN SATURDAY`S DEPARTING SHORT
WAVE...AND THE NEXT SHORT WAVE THAT WILL BE DROPPING SE ACROSS THE
OH VALLEY. FORECAST SOUNDINGS SUGGEST NEAR-NORMAL HIGHS IN THE LOWER
TO MID 50S. SUNDAY NIGHT...THE AFOREMENTIONED SHORT WAVE WILL CROSS
THE MOUNTAINS WHILE THE ASSOC SFC LOW MOVES FROM THE LOWER OH VALLEY
SUNDAY EVENING EWD TO CENTRAL NC BY 12Z MONDAY. A PLUME OF MOISTURE
AND PERHAPS A NARROW BAND OF LIGHT SHOWERS ALONG THE ATTENDANT COLD
FRONT AND INVOF OF THE TRIPLE POINT WILL MOVE ACROSS CENTRAL NC IN
THE PREDAWN HOURS. DESPITE NOTABLE COOLING ALOFT...ALL FORECAST
SOUNDINGS ACROSS CENTRAL NC SHOW LOW LEVELS WARM ENOUGH FOR ALL RAIN
WITH THIS BAND OF SHOWERS...EVEN ACROSS THE TRIAD. LOWS MONDAY
MORNING IN THE MID TO UPPER 30S.
DURING THE DAYTIME MONDAY...THE MID LEVEL TROUGH AXIS IS PROGGED TO
CROSS CENTRAL NC...ALONG WITH THE TRIPLE POINT LOW TAKING OVER AND
STRENGTHENING OFFSHORE OF KHSE. A FEW ADDITIONAL SHOWERS WILL BE
POSSIBLE ACROSS OUR AREA (ESP OUR NORTHERN/NE ZONES) AS THE TROUGH
AXIS MOVES ACROSS...BUT MOISTURE IS MODEST AND CONSENSUS MODEL QPF
FOR THE DAYTIME MONDAY IS WELL UNDER ONE TENTH INCH. WITH THE BL
WIND SHIFT TO N AND THE START OF LOW LEVEL CAA NOT OCCURRING UNTIL
AFTER NOON...BOUNDARY LAYER TEMPS WILL BE WARM ENOUGH SUCH THAN ANY
PRECIP DURING THE DAYTIME MONDAY SHOULD BE ALL RAIN. BY 00Z
TUESDAY...FORECAST SOUNDINGS SUGGEST ENOUGH LOW LEVEL COOLING WILL
HAVE OCCURRED THAT ANY LINGERING SHOWERS ACROSS OUR NE ZONES (INVOF
OF DEEPER MOISTURE UNDER THE TROUGH AXIS) MAY MIX WITH OR CHANGE TO
SNOW SHOWERS. BUT AGAIN...KEEP IN MIND THAT MODEL QPF VALUES ARE
VERY LIGHT...SO PERHAPS ONLY FLURRIES OR VERY LIGHT SNOW SHOWERS
WITH NO ACCUM...IF ANY PRECIP AT ALL. AS ALWAYS THE CASE WITH THESE
SYSTEMS...IT`S A CLOSE TIMING ISSUE BETWEEN ARRIVAL OF COLDER AIR
AND DEPARTURE OF MOISTURE.
MONDAY NIGHT...ANOTHER TRAILING SHORT WAVE IS PROGGED TO DIVE SOUTH
FROM THE GREAT LAKES REGION...REACHING THE MID ATLANTIC REGION BY
TUESDAY MORNING OR AFTERNOON. WHILE THE AIRMASS ACROSS OUR AREA BY
THEN WOULD BE COLD ENOUGH FOR SNOW...THE DEEPEST MOISTURE AND BEST
CHANCE FOR ANY PRECIP APPEARS TO REMAIN TO OUR NORTH AND EAST PER
GFS...OR LITTLE IF ANY MOISTURE AT ALL ACROSS OUR AREA PER ECMWF.
FOR NOW...WILL KEEP POPS LOW ACROSS OUR AREA GIVEN LOW CONFIDENCE.
HIGHS ON TUESDAY WILL BE DEPENDENT ON PRECIP CHANCES...BUT FOR NOW
WILL MAINTAIN LOWER 40S.
FAIR WEATHER WEDNESDAY THROUGH EARLY THURSDAY IN THE WAKE OF THE
DEPARTING TROUGH...BUT TEMPS BELOW NORMAL THANKS TO DEEP N-NW FLOW.
YET ANOTHER SHORT WAVE WILL QUICKLY APPROACH LATE THURSDAY AND MOVE
ACROSS EARLY FRIDAY. RIGHT NOW THE MODELS SUGGEST A DRY TROUGH
PASSAGE THANKS TO ANTECEDENT DRY NW FLOW.
&&
.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
AS OF 215 PM FRIDAY...
AVIATION CONDITIONS FURTHER DETERIORATE TO LIFR-IFR...THROUGH THE
AFTERNOON AND EVENING. IN ADDITION...THE ARRIVAL OF AN EAST
SOUTHEASTERLY TO SOUTHERLY LOW LEVEL JET AT 2000 FT...ATOP MUCH
LIGHTER EASTERLY WINDS AT THE SURFACE...WILL PROMOTE A GOOD CHANCE
OF LOW LEVEL WIND SHEAR CONDITIONS AT EASTERN TERMINALS THIS
EVENING. PERIODS OF RAIN AND DRIZZLE...AND LIFR CONDITIONS...WILL
CONTINUE OVERNIGHT...AS THE LOW PRESSURE SYSTEM TRACKS JUST INLAND
OF THE COAST OF THE CAROLINAS.
OUTLOOK: RAIN WILL LINGER THROUGH EARLY SATURDAY. WHILE CEILINGS AND
VISIBILITIES GRADUALLY RISE THROUGH MVFR RANGE...TO VFR BY MID TO
LATE MORNING IN THE NW... AND IN THE EAST BY EARLY AFTERNOON... AS
THE LOW PRESSURE SYSTEM TRACKS UP THE MIDDLE ATLANTIC COAST AND AWAY
FROM CENTRAL NC.
VFR CONDITIONS ARE EXPECTED SUNDAY INTO MID NEXT WEEK AS MOST
WEATHER MAKERS SHOULD REMAIN JUST TO OUR NORTH.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...BADGETT
LONG TERM...NP
AVIATION...BADGETT
AREA FORECAST DISCUSSION
NWS RALEIGH NC
230 PM EST FRI JAN 23 2015
.SYNOPSIS...A LOW PRESSURE SYSTEM WILL TRACK NORTHEAST OVER THE
EASTERN CAROLINA`S TONIGHT AND EARLY SATURDAY. THE MAIN COLD FRONT
WILL PUSH THROUGH OUR REGION SATURDAY. ANOTHER COLD FRONT WILL
APPROACH FROM THE NORTHWEST SUNDAY NIGHT AND EARLY MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 PM FRIDAY...
COLD RAINY WEATHER TONIGHT INTO EARLY SATURDAY...
SURFACE HIGH PRESSURE CONTINUED TO RETREAT OFFSHORE THIS AFTERNOON
AS LOW PRESSURE TRACKED ALONG THE GULF COAST STATES. RAIN BECAME
WIDESPREAD ACROSS THE CAROLINA`S TODAY WITH SOME AREAS REPORTING A
BRIEF MIXTURE OF SLEET AND RAIN AT THE PRECIPIATION ONSET FROM THE
TRIAD TO ROXBORO. THE HIGH TO THE NORTH WAS RETREATING RAPIDLY
OFFSHORE THIS MORNING WHICH QUICKLY CUT OFF ANY SOURCE OF COLD AIR
INTO OUR REGION. INSTEAD... A SOUTHEAST TO SOUTH FLOW INCREASED JUST
ABOVE THE SURFACE WITH RAPIDLY MOISTENING AND WARMING COLUMN OUT IN
ADVANCE OF THE APPROACHING DEEP MID/UPPER TROUGH OVER THE LOWER
MISSISSIPPI VALLEY. AS THIS TROUGH APPROACHES... THEN CROSSES OVER
THE REGION TONIGHT... THE SURFACE LOW CURRENTLY DEVELOPING OVER THE
FLORIDA PANHANDLE WILL TURN NORTHEAST ALONG THE COASTAL PLAIN OF
GA/SC/NC OVERNIGHT. WITH SURFACE TEMPERATURES SAFELY ABOVE FREEZING
AND WITH SATURATION IN PLACE AT THE SURFACE... AND EVEN CONTINUED
WARMING ALOFT... PLAIN RAIN WILL CONTINUE TO BE DOMINATE OVER NC.
THE TEMPERATURES SHOULD BE NEAR THE LOWS ALREADY THIS AFTERNOON (IN
THE MID 30S)... WITH READINGS EXPECTED TO REMAIN STEADY OR SLOWLY
RISE (ESPECIALLY ALONG I-95 OVERNIGHT). THE RELATIVELY FAST MOVEMENT
OF THE LOW PRESSURE (REACHING NEAR ELIZABETH CITY BY 09Z/SAT) SHOULD
COMBINE WITH THE STRONG IN-SITU COLD AIR DAMMING EVENT OVER THE
PIEDMONT TO LIMIT THE WESTWARD OR INLAND PUSH OF THE COASTAL FRONT.
TEMPS OVER THE COASTAL PLAIN MAY WELL RISE TO AROUND 50 LATE
TONIGHT... WHILE READINGS REMAIN IN THE MID 30S OVER THE NW
PIEDMONT.
QPF MAY BE A BIT LESS THAN EARLIER ANTICIPATED AS THE DEEP
CONVECTION CONTINUES TO BE ROLLING ALONG FROM THE GULF TO FLORIDA...
HAVING SOME NEGATIVE IMPACT ON QPF INLAND. JUST HOW MUCH THIS
AFFECTS OUR STORM TOTALS IS OF LOW CONFIDENCE. THE LATEST HRRR AND
THE OPERATIONAL MODELS GENERALLY DEPICT ABOUT 1/3 LESS QPF THAN THE
EARLIER 1-2 INCH FORECAST. WE WILL TREND A BIT LOWER - WHICH WOULD
LESSEN THE RUNOFF POTENTIAL FOR OUR REGION - WHICH WAS NOT
ANTICIPATED TO CREATE MAJOR PROBLEMS EVEN WITH 1-2 INCHES STORM
TOTALS. THE HRRR... WHICH ACTUALLY VERIFIED WELL WITH P-TYPE AND
TIMING TODAY... INDICATES THE MAIN BACK EDGE OF THE LARGE RAIN
SHIELD MAY EDGE INTO THE SW PIEDMONT BY AT LEAST 06Z AND THE REST OF
THE REGION BY 12Z/SAT. HOWEVER... THERE MAY BE ADDITIONAL "FILL IN"
OF ANY DRY HOLES INLAND SC/NC IF/WHEN THE DEEP SOUTH/FLORIDA
CONVECTION DISSIPATES. THE THUNDERSTORM THREAT IS MINIMAL OVER OUR
REGION GIVEN THE TRACK OF THE LOW AROUND OR JUST EAST OF I-95... AS
MOST OF THE REGION WILL REMAIN IN THE CAD REGION. THE HEAVIEST QPF
AROUND 1 TO 1.5 INCHES IS STILL FORECAST OVER AND EAST OF THE
TRIANGLE... WITH AMOUNTS LIKELY 0.50 TO 0.75 IN THE NW. -BADGETT
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
AS OF 230 PM FRIDAY...
THE MAIN RAIN EVENT WILL END BETWEEN 09Z/15Z SW TO NE ACROSS OUR
REGION SATURDAY AS THE STORM BOMBS AS IT MOVES AWAY FROM DELMARVA.
THE TRAILING DEFORMATION BAND OF PRECIPITATION WITH THE MID LEVEL
LOW IS EXPECTED TO WEAKEN AND DISSIPATE AS IT SPREADS EAST FROM
KY/TN/WVA INTO WESTERN VA AND NORTH-CENTRAL NC SATURDAY. IN
ADDITION... THE BOUNDARY LAYER WINDS WILL SHIFT TO THE WNW AND
INCREASE TO 10-20 MPH IN DOWNSLOPE FASHION DURING THE AFTERNOON.
THIS SHOULD LEAD TO SHARP CLEARING FROM OFF THE BLUE RIDGE INTO THE
PIEDMONT DURING THE AFTERNOON. SKIES SHOULD BECOME PARTLY SUNNY DOWN
EAST LATE IN THE AFTERNOON. HIGHS SHOULD RETURN INTO THE 45-55 RANGE
NW TO SE. THE SKIES SHOULD REMAIN MOSTLY CLEAR TO PARTLY CLOUDY
SATURDAY NIGHT. LOWS 30-35 WITH DIMINISHING NW BREEZES IN THE
EVENING.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 345 AM FRIDAY...
JUST AS QUICKLY AS THE CLOUDINESS AND SHOWERS ASSOCIATED WITH THE
"ALBERTA CLIPPER"/NORTHERN STREAM SHORTWAVE WAVE MOVE OUT...
ADDITIONAL SHEAR VORTICITY IN FAST NW FLOW ALOFT WILL AMPLIFY INTO
THE TROUGH BASE...TO NEAR AND JUST OFFSHORE THE COAST OF THE
CAROLINAS...THROUGH WED MORNING. TYPICAL MEDIUM RANGE TIMING AND
AMPLITUDE DISTANCES BECOME MAGNIFIED DURING THIS TIME...WITH THE 00Z
ECMWF REPRESENTING THE SOUTHERNMOST - AND CONSEQUENTLY RELATIVELY
WETTEST FOR CENTRAL NC - SOLUTIONS FOR THE PERIOD MON-TUE. BASED ON
A PREFERRED SLIGHTLY LESS AMPLIFIED/MORE NORTHWARD CONSENSUS OF
MODEL CLUSTERING REPRESENTED WELL BY THE 00Z GFS...THE RELATIVE
HIGHEST PROBABILITY OF PRECIPITATION (IN THE CHANCE RANGE) SHOULD BE
CENTERED TOWARD THE NORTHEAST PIEDMONT WITH THE ARRIVAL OF THE LEAD
SHEAR VORTICITY AND POSSIBLE INTERACTION WITH A LOW LEVEL MOIST AXIS
OVER EASTERN NC THROUGH MON NIGHT. ANY PRECIPITATION THAT WERE TO
FALL AFTER DARK MON...AFTER TEMPERATURES PEAK IN THE UPPER 40S TO
LOWER 50S...WOULD BE IN THE FORM OF LIGHT SNOW OWING TO STRONG DEEP
LAYER COOLING MON NIGHT - A CASE OF "THE COLD AIR CHASING THE
MOISTURE".
TRAILING SHEAR VORTICITY WILL CARVE THE TROUGH OFF THE COAST OF THE
CAROLINAS TUE-TUE NIGHT. ASSOCIATED RE-STEEPENING OF THE LAPSE RATES
ALOFT...AND LIFT/MOISTENING OF THE COLUMN...WILL RESULT IN YET
ANOTHER SLIGHT TO CHANCE OF RAIN SHOWERS - OR SNOW SHOWERS WHERE/IF
THE SUB-CLOUD LAYER FULLY WET-BULBS AND THEORETICALLY "MELTS OUT" A
PROJECTED 1500-2000 FT ABOVE FREEZING BOUNDARY LAYER. THE REMAINDER
OF THE LONG TERM WILL BE DRY AND CHILLY... PARTICULARLY WITH RESPECT
TO LOWS BOTH WED AND THU MORNINGS...AS MODIFIED ARCTIC HIGH PRESSURE
DRIFTS OVERHEAD IN THE WAKE OF THE TROUGH AXIS MOVING AWAY FROM THE
NC COAST.
&&
.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
AS OF 215 PM FRIDAY...
AVIATION CONDITIONS FURTHER DETERIORATE TO LIFR-IFR...THROUGH THE
AFTERNOON AND EVENING. IN ADDITION...THE ARRIVAL OF AN EAST
SOUTHEASTERLY TO SOUTHERLY LOW LEVEL JET AT 2000 FT...ATOP MUCH
LIGHTER EASTERLY WINDS AT THE SURFACE...WILL PROMOTE A GOOD CHANCE
OF LOW LEVEL WIND SHEAR CONDITIONS AT EASTERN TERMINALS THIS
EVENING. PERIODS OF RAIN AND DRIZZLE...AND LIFR CONDITIONS...WILL
CONTINUE OVERNIGHT...AS THE LOW PRESSURE SYSTEM TRACKS JUST INLAND
OF THE COAST OF THE CAROLINAS.
OUTLOOK: RAIN WILL LINGER THROUGH EARLY SATURDAY. WHILE CEILINGS AND
VISIBILITIES GRADUALLY RISE THROUGH MVFR RANGE...TO VFR BY MID TO
LATE MORNING IN THE NW... AND IN THE EAST BY EARLY AFTERNOON... AS
THE LOW PRESSURE SYSTEM TRACKS UP THE MIDDLE ATLANTIC COAST AND AWAY
FROM CENTRAL NC.
VFR CONDITIONS ARE EXPECTED SUNDAY INTO MID NEXT WEEK AS MOST
WEATHER MAKERS SHOULD REMAIN JUST TO OUR NORTH.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...BADGETT
LONG TERM...MWS
AVIATION...BADGETT
AREA FORECAST DISCUSSION
NWS PORTLAND OR
223 PM PST FRI JAN 23 2015
.SYNOPSIS...A WARM FRONT WILL CONTINUE TO MIGRATE NORTH TONIGHT AS
HIGH PRESSURE ALOFT STRENGTHENS. THE UPPER RIDGE CONTINUES TO BUILD
OVER THE WEEKEND AND WILL RESULT IN UNSEASONABLY WARM TEMPERATURES
FOR THE COAST AND HIGHER TERRAIN INTO EARLY NEXT WEEK. INLAND VALLEYS
WILL BE TRAPPED UNDER STRONG INVERSIONS WITH COOLER TEMPERATURES AND
PERSISTENT FOG AND LOW CLOUDS. A FEW LIGHT SHOWERS APPEAR POSSIBLE
TOWARDS THE MIDDLE OF NEXT WEEK...BUT DRY WEATHER WILL LIKELY RETURN
LATER IN THE WEEK.
&&
.SHORT TERM...TONIGHT THROUGH MONDAY...KRTX DUAL-POL DOPPLER RADAR AT
21Z SHOWED A BROAD AREA OF GENERALLY LIGHT PRECIP ACROSS SW WA AND
MOST OF NW OREGON WEST OF THE CASCADES. LATEST RADAR TREND IN THE
PAST HOUR HAS SHOWN A DISTINCT BACK EDGE TO THE PRECIP ALONG THE
COAST. RAINFALL RATES AT KAST HAVE DIMINISHED TO A FEW HUNDREDTHS PER
HOUR...VERSUS THE .10 TO .15 PER HOUR LATE THIS MORNING. WATER VAPOR
IMAGERY WITH NAM AND GFS 500 MB HEIGHTS OVERLAYED INDICATES A 590+DM
500 MB HIGH PRES CENTER AROUND 30N 137W WITH THE 576 DM HEIGHT
CONTOUR PUSHING INTO SWRN WA.
NESDIS OPERATIONAL BLENDED TOTAL PRECIPITABLE WATER (TPW) IMAGERY AT
19Z SHOWED A GRADUAL DECREASE IN OVERALL TPW SINCE EARLIER THIS
MORNING. THE 19Z DATA SHOWED A SMALL AREA OF 1.25 INCH OR SO TPW OVER
EXTREME NW OREGON AND INTO SW WA. THE 12Z GFS AND NAM ISENTROPIC
ANALYSIS ALONG THE 290K SURFACE SHOWS THE BEST LIFT FOCUSED OVER SW
WA AND THE N OREGON COASTAL AREAS THROUGH 00Z SAT. BEST ISENTROPIC
LIFT THIS AFTERNOON LOOKS TO BE CONFINED TO INLAND ARAS N OF A
NEWPORT-TO-ALBANY LINE. THE 19Z HRRR RUN ALSO SHOWED THE PRECIP BAND
MOVING E OF THE CASCADES BY LATE AFTERNOON. DESPITE THE RATHER MOIST
AIR MASS ASSOCIATED WITH THE WARM FRONT...THE BULK OF THE PRECIP WILL
BE HEADED FOR WA. GFS 6-HR QPF FORECAST SHOWS AROUND A QUARTER INCH
FOR SW WA AND FAR NW OREGON WITH LITTLE TO NOTHING SOUTH OF KSLE.
PATTERN CHANGES RATHER DRAMATICALLY OVER THE WEEKEND...MORE TOWARD A
LATE-SPRING OR EARLY SUMMER REGIME INSTEAD OF WINTER. STRONG UPPER
LEVEL RIDGING WILL ASSERT ITSELF ACROSS THE REGION THIS WEEKEND.
OPTED TO REMOVE THE SAT AM POPS OVER THE N AS THE LATEST ECMWF AND
GFS SHOW THE PRECIP SHIELD SHOVED FURTHER N INTO WA. BY 18Z SAT THE
579 DM CONTOUR IS INTO SW WA. THE AIR MASS ALOFT WILL BE UNSEASONABLY
WARM FOR THIS TIME OF YEAR. THE 00Z NAEFS 850 MB TEMP JUMPS TO THE
99TH PERCENTILE 12Z SAT...THEN REACHES ALL-TIME MAX VALUES 06Z SUN
THROUGH MON. ANOTHER WAY TO LOOK AT IT IS BY THE STANDARDIZED
ANOMALY. 850 TEMPS ARE FORECAST TO BE 3-4 STANDARD DEVIATIONS ABOVE
NORMAL 18Z SAT THROUGH MON. THE ECMWF HAS BEEN VERY CONSISTENT IN
BRINGING 850 MB TEMPS UP TO +10 DEG C ACROSS THE WILLAMETTE VALLEY
SATURDAY...THEN +18 DEG C SUNDAY. TO GIVE AN IDEA OF HOW WARM THIS
AIR MASS IS... 850 MB TEMPS FORECAST BY NEARLY ALL MODELS SUNDAY ARE
WARMER THAN THE AVERAGE 850 MB TEMPERATURE IN AUGUST. GRANTED LOW SUN
ANGLE WILL LIMIT TEMPERATURES...BUT DO NOT BE SURPRISED IF AREAS IS
THE OREGON COAST RANGE AND CASCADE FOOTHILLS HIT 70 DEGREES. THE NAMM
MODEL SOUNDING FOR KPDX VALID SUN MORNING INDICATES 60-65 DEG AT
2000-2500 FT. INTERIOR VALLEY MAX TEMP FORECASTS WILL BE TRICKY.
SITES SUCH AS KPDX SHOULD HAVE A BETTER CHANCE OF CLEARING COMPARED
TO KSLE AND KEUG. IF THIS PATTERN OCCURED JUST A MONTH LATER...IN MID
TO LATE FEBRUARY...INTERIOR VALLEYS WOULD STAND A MUCH BETTER CHANCE
OF AT LEAST PARTIALLY MIXING OUT THE LOW-LEVEL INVERSIONS AND
REACHING AT LEAST 60 DEG.
THE STRONG UPPER LEVEL RIDGE WILL LIKELY RESULT IN A BUILDING COOL
POOL IN THE WILLAMETTE VALLEY. THIS SHOULD GENERATE A MESOSCALE HIGH
PRESSURE SYSTEM INLAND...AND KEEP LIGHT OFFSHORE FLOW ALONG THE COAST
SUNDAY WITH THE END RESULT BEING MAX TEMPS IN THE MID TO UPPER 60S.
IT IS PRETTY SAFE TO SAY AT LEAST A COUPLE MAX TEMP RECORDS WILL
FALL. 850MB TEMPS DIP JUST A BIT MON...BUT SHOULD STILL SEE PLENTY OF
60S IN THE OREGON COAST RANGE AND CASCADE FOOTHILLS. ONE OTHER
CONCERN WILL BE AIR QUALITY FOR THE INTERIOR CENTRAL AND SRN VALLEYS
DUE TO THE IMPENDING STRONG VALLEY INVERSIONS. WEISHAAR
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY...VALLEY FOG AND LOW CLOUDS
LOOK TO STICK AROUND THROUGH EARLY TUESDAY. HOWEVER...AS THE FLOW
PATTERN BECOMES MORE SOUTHERLY ON TUESDAY WE CAN EXPECT TO SEE AN
INCREASE IN MOISTURE FROM THE SOUTH. BUMPED UP THE POPS SLIGHTLY TO
ACCOUNT FOR A CHANCE OF SOME SCATTERED SHOWERS. A WEAK FRONT LOOKS
TO MOVE THROUGH ON LATE TUESDAY/EARLY WEDNESDAY AND IS THE MOST
PROMISING CHANCE OF RAIN IN THE UPCOMING WEEK...BUT DETAILS ARE
STILL A BIT SKETCHY. THE UPPER LEVEL RIDGE LOOKS TO REBUILD LATE
NEXT WEEK BRINGING THE RETURN OF VALLEY FOG AND LOW CLOUDS...AND
BENIGN CONDITIONS. AFTERNOON TEMPERATURES THROUGH THE EXTENDED
FORECAST WILL CONTINUE TO BE UNSEASONABLY WARM AT MOST LOCATIONS. /64
&&
.AVIATION...CURRENTLY MVFR/IFR CIGS AND VIS ALONG THE
COAST...WHILE INLAND SITES ARE PRIMARILY VFR. CIGS AND VIS OVER THE
NORTH OR/SOUTH WA COAST WILL LIKELY LOWER TO IFR OVERNIGHT
TONIGHT AS RAIN CONTINUES ALONG THE COAST AND MOISTURE CONTINUES
TO BE PUSHED ONSHORE. THE CENTRAL OR COAST...THOUGH...WILL LIKELY
BOUNCE BETWEEN MVFR/IFR OVERNIGHT AS MOST OF THE MOISTURE REMAINS
TO THE NORTH. INLAND SITES WILL SEE CIGS AND VIS LOWER TO MVFR/IFR
TONIGHT WITH FOG DEVELOPING EARLY SATURDAY IN THE SOUTH AND
CENTRAL WILLAMETTE VALLEY. PATCHY FOG IS POSSIBLE IN THE NORTH
WILLAMETTE VALLEY...BUT MAINLY IN AREAS PROTECTED FROM THE WIND SUCH
AS KHIO. MODELS ARE SUGGESTING THAT STRATUS SHOULD LIFT TO VFR BY
LATE MORNING OR EARLY AFTERNOON ACROSS THE AREA...BUT THERE IS A
CHANCE IF KEUG SEES ANY CLEARING TONIGHT THAT DENSE FOG COULD
DEVELOP...KEEPING THIS SITE MVFR/IFR ALL DAY SATURDAY.
KPDX AND APPROACHES...VFR CONDITIONS EXPECTED TO CONTINUE INTO THE
OVERNIGHT HOURS...THOUGH VISUAL APPROACHES WILL LIKELY BECOME
LIMITED AS CIGS LOWER TO AROUND 030 TO 040 AFTER 01Z THIS
EVENING. CIGS CONTINUE TO LOWER EARLY SATURDAY...FALLING TO AROUND
025 AFTER 12Z...WITH MVFR VIS AS WELL. CONDITIONS EXPECTED TO
IMPROVE TO VFR BY 19Z SATURDAY. -MCCOY
&&
.MARINE...WARM FRONT HAS MOVED ONSHORE...AND GUSTY SOUTHERLY WINDS
ARE OCCURRING OVER THE WATERS. WINDS AROUND 20 TO 25 KTS GUSTING
TO 30 KTS ARE BEING OBSERVED AT BUOY 29. GUSTY WINDS OVER THE
WATERS COULD EXTEND INTO SATURDAY AFTERNOON AS A LOW PRESSURE
CENTER REMAINS WELL NORTHWEST OF THE REGION. MODELS ARE NOT IN
GOOD AGREEMENT ON THE TIMING THAT WINDS WILL WEAKEN...BUT GFS AND
NAM ARE LEANING TOWARDS WINDS PERSISTING UNTIL SATURDAY
AFTERNOON SO EXTENDED SMALL CRAFT ADVISORY FOR WINDS OVER THE
NORTHERN OUTER WATERS TO INCLUDE SATURDAY AFTERNOON.
SEAS ARE CURRENTLY AROUND 10 FT AND WILL CONTINUE TO INCREASE...
PEAKING AROUND 13 FT LATER THIS EVENING. SEAS WILL REMAIN AROUND
10 TO 12 FT THROUGH SUNDAY BEFORE DROPPING BELOW 10 FT LATE
SUNDAY OR EARLY MONDAY. -MCCOY
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 PM PST SATURDAY FOR
WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10
TO 60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 AM PST SUNDAY
FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT
60 NM.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 PM PST THIS EVENING FOR
COASTAL WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR
OUT 10 NM.
SMALL CRAFT ADVISORY FOR WINDS UNTIL 4 PM PST THIS AFTERNOON
FOR WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 10 PM
PST SATURDAY.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
457 PM CST FRI JAN 23 2015
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 250 PM CST FRI JAN 23 2015
THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SHORTWAVE
TROUGH MOVING TO THE EAST-SOUTHEAST OVER FAR NORTHWEST WISCONSIN AND
THE WESTERN UPPER PENINSULA. AHEAD OF THIS SHORTWAVE...A MID AND
UPPER LEVEL FRONT COMBINED WILL MID-LEVEL LAPSE RATES OF 6.5-7.0
C/KM ARE CONTRIBUTING TO A BAND OF LIGHT PRECIP. SURFACE OBS AND A
FEW REPORTS INDICATE THAT THE PTYPE IS MAINLY SNOW...OCCASIONALLY
MIXED WITH SLEET. THE LEADING EDGE OF THIS PRECIP BAND IS
FIGHTING DRY AIR...BUT PRECIP IS REACHING THE GROUND FROM MEDFORD TO
MARINETTE. THIS BAND OF PRECIP WILL CONTINUE TO MOVE SOUTHEAST AND
CLEAR THE FORECAST AREA EARLY THIS EVENING. EXPECTING LITTLE TO NO
ACCUMULATION WITH ANY SNOW...BUT IT WILL LIKELY BRIEFLY DROP
VSBYS TO 2SM IN SPOTS. BEHIND THE SHORTWAVE...AN AREA OF CLEARING
IS MOVING SOUTHEAST OVER CENTRAL MINNESOTA TO THE FAR WESTERN UPPER
PENINSULA. THEN ANOTHER AREA OF STRATUS OVER NORTHERN MINNESOTA IS
DIVING SOUTHEAST AND WILL REACH N-C WISCONSIN BETWEEN 21Z-00Z.
PRECIP AND SKY TRENDS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...THE SHORTWAVE AND MID-LEVEL FRONT WILL BE MOVING
SOUTHEAST ACROSS NORTHEAST AND EAST-CENTRAL WISCONSIN EARLY IN THE
EVENING. LEFT A SLIGHT CHANCE OF LIGHT SNOW IN THE FORECAST UNTIL
7PM WHEN THINK ANY PRECIP WILL HAVE EXITED THE AREA. BEHIND THE
FRONT...SKIES WILL EVENTUALLY BECOME MOSTLY CLEAR OR PARTLY CLOUDY
FOR A PERIOD THIS EVENING BEFORE LOW STRATUS OVER NORTHERN MINNESOTA
SPREADS SOUTHEAST ACROSS NORTHERN WISCONSIN. MODELS APPEAR TO BE
TOO AGGRESSIVE WITH LOW LEVEL MOISTURE...SO SLOWED DOWN THE ARRIVAL
OF THIS STRATUS. BUT ONCE IT MOVES IN...THINK OVERCAST CONDITIONS
WILL STICK AROUND FOR THE REST OF THE NIGHT. THE PREVIOUS FORECAST
INCLUDED A CHANCE OF FLURRIES AND FREEZING DRIZZLE IN THE SNOWBELT.
BUT LOOKING AT PROGGED SOUNDINGS...MOISTURE DEPTH IS SHALLOW BELOW
850MB SO AM SKEPTICAL THAT PRECIP WILL OCCUR. BUT DOES NOT TAKE
MUCH THIS TIME OF THE YEAR...SO LEFT IN THE FORECAST TO MATCH UP
WITH SURROUNDING OFFICES. LOWS IN THE MIDDLE TO UPPER 20S.
SATURDAY...SHALLOW ARCTIC COLD FRONT WILL BE DROPPING SOUTH ACROSS
LAKE SUPERIOR TO THE U.P. BORDER DURING THE AFTERNOON. AHEAD OF
THIS BOUNDARY...THE LOW STRATUS WILL BE HARD TO REMOVE ESPECIALLY
WITH MID AND HIGH CLOUDS MOVING OVERHEAD AHEAD OF THE NEXT CLIPPER.
PRECIPITATION AHEAD OF THE SHORTWAVE SHOULD REMAIN WELL WEST OF THE
REGION THROUGH THE AFTERNOON. MAY SEE A FEW FLURRIES OR VERY PATCHY
FREEZING DRIZZLE ACROSS N-C WISCONSIN WITH NW WINDS IN PLACE...BUT
NOT EXPECTING ANY ACCUMULATIONS. HIGH TEMPS MAINLY IN THE LOWER TO
MIDDLE 30S.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 250 PM CST FRI JAN 23 2015
MEAN FLOW ALOFT IS EXPECTED TO REMAIN FROM THE NORTHWEST LATE THIS
WEEKEND AND THROUGHOUT THE UPCOMING WEEK. THE MAIN FOCUS OF THIS
FORECAST IS ON SATURDAY NIGHT THROUGH MONDAY NIGHT AS A COUPLE OF
CLIPPER SYSTEMS IMPACT THE AREA. THE AXIS OF HEAVIEST SNOW WITH
THE SATURDAY NIGHT/SUNDAY SYSTEM WILL BE TO OUR SOUTHWEST...CLOSER
TO THE SURFACE LOW AND BETTER UPPER LEVEL SUPPORT. THE 12Z GFS
ONLY HAD SMALL QPF IN PARTS OF MARATHON COUNTY AND WOOD COUNTY
06Z-12Z SUNDAY...OTHER MODELS GENERALLY HAD QPF ACROSS MOST OR ALL
OF THE FORECAST AREA. KEPT CLOSE TO WHAT SURROUNDING OFFICES HAD
ALONG OUR BORDERS AND WHAT THE MAJORITY OF THE MODELS HAD FOR POPS
AND QPF. THIS RESULTED IN A SMALLER CHANGE TO FORECAST SNOW
TOTALS THAN WPC GUIDANCE...WHICH HAD LESS THAN AN INCH EVEN IN
CENTRAL WISCONSIN...WOULD SUGGEST.
SNOW TOTALS ARE EVEN MORE UNCERTAIN WITH THE NEXT SYSTEM THAT IS
EXPECTED TO BRING SNOW TO THE AREA MONDAY INTO MONDAY NIGHT. WENT
NO HIGHER THAN CHANCE POPS WITH THE SYSTEM. ONCE IT DEPARTS THERE
COULD BE SOME LAKE EFFECT SNOW SHOWERS IN FAR NORTH CENTRAL
WISCONSIN ON TUESDAY. ANOTHER SYSTEM MAY IMPACT THE AREA ON
WEDNESDAY NIGHT/THURSDAY...BUT FORECASTER CONFIDENCE THIS FAR OUT
IS RATHER POOR.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 455 PM CST FRI JAN 23 2015
NO REAL CHG TO FCST REASONING FM PREVIOUS ISSUANCE. MVFR CIGS
STILL WIDESPREAD BACK TO THE NW...AND EXPECT THESE TO OVERSPREAD
THE AREA THIS EVENING. ONCE IN PLACE...THEY WL PROBABLY LINGER
THROUGH AT LEAST TOMORROW.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......MG
AVIATION.......SKOWRONSKI
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND SATURDAY
ISSUED AT 250 PM CST FRI JAN 23 2015
THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A SHORTWAVE
TROUGH MOVING TO THE EAST-SOUTHEAST OVER FAR NORTHWEST WISCONSIN AND
THE WESTERN UPPER PENINSULA. AHEAD OF THIS SHORTWAVE...A MID AND
UPPER LEVEL FRONT COMBINED WILL MID-LEVEL LAPSE RATES OF 6.5-7.0
C/KM ARE CONTRIBUTING TO A BAND OF LIGHT PRECIP. SURFACE OBS AND A
FEW REPORTS INDICATE THAT THE PTYPE IS MAINLY SNOW...OCCASIONALLY
MIXED WITH SLEET. THE LEADING EDGE OF THIS PRECIP BAND IS
FIGHTING DRY AIR...BUT PRECIP IS REACHING THE GROUND FROM MEDFORD TO
MARINETTE. THIS BAND OF PRECIP WILL CONTINUE TO MOVE SOUTHEAST AND
CLEAR THE FORECAST AREA EARLY THIS EVENING. EXPECTING LITTLE TO NO
ACCUMULATION WITH ANY SNOW...BUT IT WILL LIKELY BRIEFLY DROP
VSBYS TO 2SM IN SPOTS. BEHIND THE SHORTWAVE...AN AREA OF CLEARING
IS MOVING SOUTHEAST OVER CENTRAL MINNESOTA TO THE FAR WESTERN UPPER
PENINSULA. THEN ANOTHER AREA OF STRATUS OVER NORTHERN MINNESOTA IS
DIVING SOUTHEAST AND WILL REACH N-C WISCONSIN BETWEEN 21Z-00Z.
PRECIP AND SKY TRENDS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...THE SHORTWAVE AND MID-LEVEL FRONT WILL BE MOVING
SOUTHEAST ACROSS NORTHEAST AND EAST-CENTRAL WISCONSIN EARLY IN THE
EVENING. LEFT A SLIGHT CHANCE OF LIGHT SNOW IN THE FORECAST UNTIL
7PM WHEN THINK ANY PRECIP WILL HAVE EXITED THE AREA. BEHIND THE
FRONT...SKIES WILL EVENTUALLY BECOME MOSTLY CLEAR OR PARTLY CLOUDY
FOR A PERIOD THIS EVENING BEFORE LOW STRATUS OVER NORTHERN MINNESOTA
SPREADS SOUTHEAST ACROSS NORTHERN WISCONSIN. MODELS APPEAR TO BE
TOO AGGRESSIVE WITH LOW LEVEL MOISTURE...SO SLOWED DOWN THE ARRIVAL
OF THIS STRATUS. BUT ONCE IT MOVES IN...THINK OVERCAST CONDITIONS
WILL STICK AROUND FOR THE REST OF THE NIGHT. THE PREVIOUS FORECAST
INCLUDED A CHANCE OF FLURRIES AND FREEZING DRIZZLE IN THE SNOWBELT.
BUT LOOKING AT PROGGED SOUNDINGS...MOISTURE DEPTH IS SHALLOW BELOW
850MB SO AM SKEPTICAL THAT PRECIP WILL OCCUR. BUT DOES NOT TAKE
MUCH THIS TIME OF THE YEAR...SO LEFT IN THE FORECAST TO MATCH UP
WITH SURROUNDING OFFICES. LOWS IN THE MIDDLE TO UPPER 20S.
SATURDAY...SHALLOW ARCTIC COLD FRONT WILL BE DROPPING SOUTH ACROSS
LAKE SUPERIOR TO THE U.P. BORDER DURING THE AFTERNOON. AHEAD OF
THIS BOUNDARY...THE LOW STRATUS WILL BE HARD TO REMOVE ESPECIALLY
WITH MID AND HIGH CLOUDS MOVING OVERHEAD AHEAD OF THE NEXT CLIPPER.
PRECIPITATION AHEAD OF THE SHORTWAVE SHOULD REMAIN WELL WEST OF THE
REGION THROUGH THE AFTERNOON. MAY SEE A FEW FLURRIES OR VERY PATCHY
FREEZING DRIZZLE ACROSS N-C WISCONSIN WITH NW WINDS IN PLACE...BUT
NOT EXPECTING ANY ACCUMULATIONS. HIGH TEMPS MAINLY IN THE LOWER TO
MIDDLE 30S.
.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY
ISSUED AT 250 PM CST FRI JAN 23 2015
MEAN FLOW ALOFT IS EXPECTED TO REMAIN FROM THE NORTHWEST LATE THIS
WEEKEND AND THROUGHOUT THE UPCOMING WEEK. THE MAIN FOCUS OF THIS
FORECAST IS ON SATURDAY NIGHT THROUGH MONDAY NIGHT AS A COUPLE OF
CLIPPER SYSTEMS IMPACT THE AREA. THE AXIS OF HEAVIEST SNOW WITH
THE SATURDAY NIGHT/SUNDAY SYSTEM WILL BE TO OUR SOUTHWEST...CLOSER
TO THE SURFACE LOW AND BETTER UPPER LEVEL SUPPORT. THE 12Z GFS
ONLY HAD SMALL QPF IN PARTS OF MARATHON COUNTY AND WOOD COUNTY
06Z-12Z SUNDAY...OTHER MODELS GENERALLY HAD QPF ACROSS MOST OR ALL
OF THE FORECAST AREA. KEPT CLOSE TO WHAT SURROUNDING OFFICES HAD
ALONG OUR BORDERS AND WHAT THE MAJORITY OF THE MODELS HAD FOR POPS
AND QPF. THIS RESULTED IN A SMALLER CHANGE TO FORECAST SNOW
TOTALS THAN WPC GUIDANCE...WHICH HAD LESS THAN AN INCH EVEN IN
CENTRAL WISCONSIN...WOULD SUGGEST.
SNOW TOTALS ARE EVEN MORE UNCERTAIN WITH THE NEXT SYSTEM THAT IS
EXPECTED TO BRING SNOW TO THE AREA MONDAY INTO MONDAY NIGHT. WENT
NO HIGHER THAN CHANCE POPS WITH THE SYSTEM. ONCE IT DEPARTS THERE
COULD BE SOME LAKE EFFECT SNOW SHOWERS IN FAR NORTH CENTRAL
WISCONSIN ON TUESDAY. ANOTHER SYSTEM MAY IMPACT THE AREA ON
WEDNESDAY NIGHT/THURSDAY...BUT FORECASTER CONFIDENCE THIS FAR OUT
IS RATHER POOR.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1127 AM CST FRI JAN 23 2015
A BAND OF LIGHT SNOW...POSSIBLY MIXED WITH SLEET...WILL BE MOVING
ACROSS CENTRAL AND NORTHEAST WISCONSIN THIS AFTERNOON. VSBYS MAY
BRIEFLY FALL TO MVFR BUT AM NOT CONFIDENT TO INCLUDE IN TAFS AT THE
MOMENT. ANY LIGHT PRECIP WILL HAVE EXITED THE TAFS SITES BY
00Z...THEN MVFR STRATUS IS EXPECTED TO MOVE SOUTHEAST ACROSS THE TAF
SITES THIS EVENING. SOME UNCERTAINTY IN REGARDS TO HOW SOON THIS
STRATUS WILL ARRIVE AS THE LATEST MODEL RUNS ARE QUITE AGGRESSIVE
WITH THE FORWARD MOTION OF THE STRATUS WHICH DOES NOT QUITE MATCH
OBSERVATIONS. WILL INCLUDE A SHORT PERIOD OF SCT CONDITIONS BEFORE
THE MVFR STRATUS ARRIVES. ONCE IT DOES...BKN TO OVC CONDITIONS ARE
EXPECTED TO REMAIN THROUGH THE DURATION OF THE FORECAST.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......MG
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1145 AM CST FRI JAN 23 2015
.UPDATE...
ISSUED AT 1145 AM CST FRI JAN 23 2015
DESPITE A WIDE SWATH OF WEAK ECHOES ON RADAR...VERY LITTLE IS REACHING
THE GROUND GIVEN VERY DRY NEAR SURFACE LAYER AND CLOUD BASES GENERALLY
5000 FT AGL OR HIGHER. A FEW FLURRIES HAVE BEEN REPORTED ACROSS
NORTHERN WI IN COLDER AIR MASS. FARTHER SOUTH ACROSS THE FORECAST
AREA...COULD STILL SEE SOME LIGHT DRIZZLE/RAIN THIS AFTERNOON...BUT
RISING AIR/GROUND TEMPERATURES TO ABOVE 32 DEGREES WILL LIMIT
FREEZING POTENTIAL. ALL SAID...WILL ALLOW WINTER WEATHER ADVISORY
TO EXPIRE AT NOON.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CST FRI JAN 23 2015
THE MAIN FOCUS FOR THE EARLY PART OF THE FORECAST IS ON THE
POTENTIAL FOR FREEZING RAIN AND SLEET THIS MORNING.
CURRENTLY...A NORTHEAST TO SOUTHWEST ORIENTED MID LEVEL SHORT WAVE
TROUGH IS DROPPING SOUTH INTO NORTHERN MINNESOTA WITH A BAND OF
LIGHT PRECIPITATION OUT AHEAD OF IT. AT THE SURFACE/LOW LEVELS...A
NORTH TO SOUTH ORIENTED WARM FRONT IS ADVANCING SOUTHEASTWARD AS
WELL ACROSS MINNESOTA WITH THIS WARM LAYER CAUSING SOME
PRECIPITATION TYPE ISSUES IN NORTHERN MINNESOTA. EVEN THOUGH
SURFACE TEMPERATURES HAVE CLIMBED ABOVE FREEZING...ROAD
TEMPERATURES ARE STILL BELOW FREEZING AND IS CAUSING SOME ICY
CONDITIONS. SIMILAR CONDITIONS ARE NOTED LOCALLY WITH ROAD SENSORS
SAYING ROAD TEMPERATURES ARE CURRENTLY IN THE UPPER 20S TO AROUND
30.
THE QUESTION LOCALLY IS WITH HOW MUCH OF THIS PRECIPITATION WILL
MAKE IT DOWN HERE AND HOW FAR SOUTHEAST WILL THE WARM LAYER MAKE
IT. 23.07Z RAP SOUNDINGS SHOW A SUBSTANTIAL DRY LAYER IN THE
LOWEST 5-6KFT OF THE PROFILE IN MOST SITES FROM POINTS SOUTH OF
SOUTHEAST MINNESOTA GOING EAST THROUGH CENTRAL WISCONSIN. FURTHER
NORTH...HOWEVER...TOWARD NORTH CENTRAL WISCONSIN THE POTENTIAL IS
THERE FOR DEEPER SATURATION AND A HIGHER CHANCE FOR PRECIPITATION.
THE WARM LAYER APPEARS TO CREEP UP TOWARD 1 TO 3C ABOVE
FREEZING...SO THERE WILL LIKELY BE SOME MELTING OF ANY ICE/SNOW
THAT TRIES TO FALL THROUGH THE COLUMN. THE WARMER PART OF THE WARM
NOSE APPEARS TO DROP DOWN FROM FAR NORTHWEST WISCONSIN DOWN TO
SOUTHEAST MINNESOTA/NORTH CENTRAL IOWA THIS MORNING...SO THE MAIN
PRECIPITATION TYPE THERE WOULD BE RAIN...IF IT PRECIPITATES. SAY
THAT IT DOES OCCUR...THE QUESTION BECOMES WHAT ROAD TEMPERATURES
WILL DO THROUGH THE MORNING.
OVERALL CONFIDENCE IS HIGHEST IN TAYLOR COUNTY THAT SOME ISSUES
WILL OCCUR WITH FREEZING RAIN/SLEET...SO WILL ADD THEM TO THE
ADVISORY. SHOULD THE PRECIPITATION MAKE IT FURTHER SOUTH...THEN A
SOUTHWARD EXPANSION TO THE ADVISORY MAY BE NEEDED...BUT CONFIDENCE
IS NOT HIGH ENOUGH AT THIS POINT TO DO THAT.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 340 AM CST FRI JAN 23 2015
THE MAIN FOCUS IN THE EXTENDED PERIOD IS WITH THE SNOW AMOUNTS ON
SATURDAY NIGHT INTO SUNDAY AS A LOW PRESSURE SYSTEM DROPS DOWN
FROM SOUTHERN CANADA. CONFIDENCE IS HIGH THAT THIS SYSTEM WILL BE
MOVING THROUGH IN THE SATURDAY NIGHT/SUNDAY TIME FRAME...BUT
CONFIDENCE IS RATHER LOW WITH THE TRACK OF THE SYSTEM. THE 23.00Z
ECMWF IS THE FURTHEST SOUTH WITH THE LEAST AMOUNT OF SNOW...THE
23.00Z NAM IS THE SLOWEST AND HAS THE NARROWEST BAND MOVING
THROUGH WEST CENTRAL WISCONSIN AND THE 23.00Z GFS IS SOMEWHERE IN
BETWEEN THESE TWO WITH THE MOST WIDESPREAD AND HEAVIEST SNOW. AT
THIS POINT...CAN ONLY TAKE THE MIDDLE OF THE ROAD WHICH ENDS UP
BEING CLOSE TO THE GFS PATH WITH LESS QPF. STILL...WITH SNOW
RATIOS OF AROUND 13:1 AND QPF OF AROUND A QUARTER OF AN
INCH...COULD SEE SOME 2 TO 4 INCH SNOWS FROM THIS QUICK MOVING
SYSTEM. INCREASED THE PRECIPITATION CHANCES FOR THE EVENT SINCE
IT IS LOOKING LIKE MOST OF THE REGION WILL SEE SOME SNOW...IT IS
JUST A MATTER OF HOW MUCH.
BEYOND THIS...ONLY MADE SOME ADJUSTMENTS TO THE WEDNESDAY HIGH
TEMPERATURE FORECAST FOR WHAT APPEARS TO BE A STRONG SOUTHERLY
FLOW DAY WITH A WARM AIR MASS MOVING IN FROM THE SOUTH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1145 AM CST FRI JAN 23 2015
VFR CONDITIONS EXPECTED AT BOTH TAF AIRFIELDS THROUGH THE
AFTERNOON. MAY EVEN SEE A FEW HOURS OF FULL SUN LATE AFTERNOON/
EARLY EVENING AS BACK EDGE OF MID-CLOUD DECK ACROSS CENTRAL MN IS
EXPECTED TO MOVE THROUGH UPPER MS RIVER VALLEY BEFORE THE NEXT
BATCH OF LOW STRATUS DROPS SOUTH FROM NORTHERN MN. DELAYED ONSET
OF THESE LOWER CEILINGS UNTIL 24.01Z AT KSRT AND 24.02Z AT KLSE.
THEREAFTER...MVFR/IFR CEILINGS WILL BE THE RULE THROUGH THE REST
OF THE TAF PERIOD. SOUTHWEST WIND WILL GRADUALLY DECREASE AND
SHIFT TO THE NORTHWEST BY THIS EVENING AND INTO THE OVERNIGHT.
LOOKING AHEAD...IFR CHANCES AND LIGHT SNOW INCREASE AT KRST/KLSE
AFTER 25.00Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL NOON CST TODAY FOR WIZ017.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...ROGERS
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...ROGERS