Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 03/11/13
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
321 AM CST SAT MAR 9 2013
.DISCUSSION...
924 PM CST
NO REAL BIG CHANGES TO GOING FORECAST TONIGHT...WITH ONLY MINOR
EDITS TO POP/WX FOR AREAS ACROSS NORTHWEST ILLINOIS.
LATEST SATELLITE IMAGERY DEPICTING MID/UPPER LEVEL CLOUD COVER
CONTINUING TO STREAM NORTHEAST ACROSS THE REGION THIS EVENING...AS
SOUTHWESTERLY FLOW CONTINUES OUT AHEAD OF AN APPROACHING LONGWAVE
TROUGH OVER THE WESTERN CONUS. THIS IS USHERING IN A WARMER AND
MORE MOIST ENVIRONMENT WITH LATEST RAP ANALYSIS DEPICTING STRONG
WAA OCCURRING ACROSS MUCH OF THE PLAINS...AND CAN BE NOTED VIA THE
ABUNDANCE OF CLOUD COVER AS WELL AS THE WIDESPREAD PRECIP SHIELD
IN THIS LOCATION. ALTHOUGH THE STRONGEST WAA WILL REMAIN JUST TO
THE WEST OF THE CWA...LATEST SHORT TERM GUIDANCE IS INDICATING
THAT SOME LIGHT PRECIP DEVELOPMENT COULD OCCUR ACROSS NORTHWEST
ILLINOIS TONIGHT AS THIS WAA WING CONTINUES TO LIFT
NORTH/NORTHEAST. PRECIP DEVELOPMENT LATE TONIGHT ACROSS AREAS
ALONG AND WEST OF INTERSTATE 39 DOES SEEM REASONABLE WITH THIS
BETTER FORCING ALREADY INCHING CLOSER TO THE CWA. ALTHOUGH THIS
FORCING WILL REMAIN RATHER WEAK...IT MAY BE ENOUGH OF A PERSISTENT
FEATURE TO OVERCOME SOME DRIER AIR IN PLACE. THERMAL PROFILES WILL
SUPPORT PRECIP OF THE LIQUID TYPE...BUT WITH THE POSSIBILITY OF A
BRIEF WINDOW OF LIGHT FREEZING RAIN. ALTHOUGH...WARMING TONIGHT
SHOULD MITIGATE ANY OVERALL FREEZING RAIN POTENTIAL WITH SURFACE
TEMPERATURES EXPECTED TO BE HOVERING AROUND FREEZING IF NOT
BEGINNING TO RISE JUST ABOVE BY THE TIME THIS PRECIP ARRIVES. SO
HAVE MADE MENTION OF A SLIGHT CHANCE OF LIGHT RAIN/LIGHT FREEZING
RAIN FOR LATE TONIGHT INTO EARLY SATURDAY MORNING BEFORE
TEMPERATURES CONTINUE TO RISE THROUGH MID SATURDAY MORNING WITH
ONLY RAIN THEN EXPECTED.
RODRIGUEZ
//PREV DISCUSSION...
234 PM CST
THE AREA WILL QUICKLY SHIFT FROM WINTER TO SPRING WEATHER THIS
WEEKEND WITH EXPECTED RAINFALL/SNOW MELT WITH WARMING TEMPERATURES
POSING A FLOOD THREAT...WITH THUNDERSTORMS NOT OUT OF THE QUESTION
BY SUNDAY. UPS AND DOWNS IN TEMPERATURES ARE EXPECTED NEXT WEEK WITH
A SERIES OF WEAKER SYSTEMS BRINGING PERIODIC LOW CHANCES FOR
PRECIPITATION.
SYNOPSIS...EARLY AFTERNOON WATER VAPOR IMAGERY SHOWS UPPER RIDGING
BUILDING ACROSS THE MISSISSIPPI RIVER VALLEY INTO THE LOCAL AREA IN
RESPONSE TO A DEEP CLOSED UPPER LOW ROTATING INTO THE DESERT
SOUTHWEST. THIS TROUGH IS SPLIT FROM A TROUGH THAT IS POSITIONED
OVER CENTRAL CANADA WITH A TROUGH AXIS SHIFTING TOWARDS WESTERN
SASKATCHEWAN. THESE TWO FEATURES WILL BE THE MAIN DRIVERS OF
EXPECTED RAINFALL THIS WEEKEND. AT THE SURFACE...A LARGE AREA OF
HIGH PRESSURE IS EXITING THE LOCAL AREA TO THE EAST. WEAK LOW
PRESSURE IS OVER SOUTHERN MANITOBA AND IS DRIFTING EASTWARD.
TONIGHT AND SATURDAY...QUIET WEATHER WILL CONTINUE TONIGHT WITH THE
UPPER RIDGE CRESTING THE AREA THIS EVENING. THE BIG SOUTHWEST
TROUGH WILL BE MOVING EASTWARD WITH HEIGHT FALLS AHEAD OF IT AND
BEHIND THE RIDGE ALLOWING LOW PRESSURE TO DEVELOP IN THE LEE OF
THE ROCKIES. A 50+KT LOW LEVEL JET WILL SET UP ACROSS THE PLAINS
RESULTING IN A STRONG PUSH OF HIGH THETA-E LOW LEVEL AIR ACROSS
THE SOUTHERN AND CENTRAL PLAINS. HIGH LEVEL MOISTURE WILL BE
SPREAD NORTHEASTWARD SUPPORTING AN INCREASE IN MID AND HIGH LEVEL
CLOUD COVER OVERNIGHT. THE PRESSURE GRADIENT WILL BE WEAK ACROSS
THE AREA EARLY BUT WILL TIGHTEN OVERNIGHT SO WINDS MAY DROP OFF
FOR A TIME EARLY BEFORE INCREASING SOMEWHAT OVERNIGHT. LOW TEMPS
WILL BE THE MAIN CHALLENGE AND MAY OCCUR DURING THE EVENING BUT
SOME WARMING MAY OCCUR LATE AS CLOUDS AND WINDS INCREASE AND WARM
ADVECTION IS UNDERWAY ALOFT. WILL GO AHEAD AND SHOW A STEADY OR
WARMING TREND OVERNIGHT. LIGHT PRECIP BECOMES A CONCERN BY
SATURDAY MORNING AS WAVES OF WARM ADVECTION BECOME MORE FOCUSED
AND MOISTURE DEEPENS. THIS IS WHERE TEMPS WILL BECOME CRITICAL
BECAUSE CHANCES FOR LIGHT PRECIP MAY BEGIN EARLY ENOUGH TO FALL AS
FREEZING RAIN. SIGNALS FOR PRECIP ARE NOT ALL THAT ORGANIZED UNTIL
SATURDAY AFTERNOON BUT WESTERN AREAS MAY HAVE DEEP ENOUGH MOISTURE
AND ENOUGH WARM ASCENT OCCURRING ALOFT TO SEE LIGHT RAIN...OR
FREEZING RAIN IF TEMPS START OUT BELOW FREEZING...BY LATE SATURDAY
MORNING. ANY FREEZING PRECIP WILL QUICKLY END AS TEMPS WARM WELL
ABOVE FREEZING BY EARLY AFTERNOON. PRECIP CHANCES WILL THEN EXPAND
EASTWARD...ESPECIALLY ACROSS THE NORTHERN CWA SATURDAY AFTERNOON
BUT CHANCES STILL LOOK RATHER LOW BUT STILL WORTH A MENTION GIVEN
STEADILY INCREASING DEEP LAYER MOISTURE /PRECIPITABLE WATER VALUES
REACH 0.75 INCHES OR SO BY LATE DAY/ AND WARM ADVECTION. SOUTH TO
SOUTHEAST WINDS WILL BECOME BREEZY WHICH WILL HELP HIGHS WARM INTO
LOW TO MID 40S NORTH AND MID TO UPPER 40S SOUTH. IT IS ALSO
IMPORTANT TO NOTE THAT DEW POINTS WILL BE ON THE RISE AS WELL
WHICH WILL COMBINE WITH THE STEADY WINDS AND MILD TEMPS TO PROVIDE
INCREASINGLY EFFICIENT SNOW MELT THROUGH THE AFTERNOON. MORE ON
THIS BELOW...
SATURDAY NIGHT AND SUNDAY...THE SOUTHWEST UPPER LOW WILL BE
LIFTING ACROSS THE SOUTHERN HIGH PLAINS AND PHASING WITH THE CENTRAL
CANADA UPPER TROUGH WHICH WILL BE SHARPENING AS IT PIVOTS
SOUTHEASTWARD. THE MAIN SURFACE LOW IS EXPECTED TO ORGANIZE IN
VICINITY OF THE SOUTHERN UPPER LOW ACROSS WESTERN KANSAS BY SATURDAY
EVENING WITH AN INVERTED TROUGH EXTENDING NORTHWARD INTO WESTERN
ONTARIO. GULF MOISTURE WILL CONTINUE TO STREAM NORTHWARD AHEAD OF
THE LOW AS 60KT LOW LEVEL JET SPREADS ACROSS
MISSOURI...ILLINOIS...AND LAKE MICHIGAN LATER SATURDAY EVENING.
PRECIPITABLE WATER VALUES WILL FURTHER SURGE REACHING THE 1 TO
PERHAPS 1.25 INCH RANGE WHICH WILL COMBINE WITH INCREASED ASCENT TO
PRODUCE WIDESPREAD RAIN ACROSS THE MID-MISSISSIPPI RIVER VALLEY
WHICH WILL THEN SPREAD EASTWARD DURING THE EVENING AND OVERNIGHT
HOURS. THE UPPER LOW WILL BE TO THE WEST OF THE AREA BY SUNDAY
MORNING WHICH WILL LIKELY BRING A DRY SLOT INTO THE AREA SOMETIME
SUNDAY MORNING. INSTABILITY DOES INCREASE AS WELL...POTENTIALLY WITH
ENOUGH ELEVATED INSTABILITY TO SUPPORT SOME THUNDER POTENTIAL ON THE
LEADING EDGE OF THE DRY SLOT. FURTHERMORE...SOME MINIMAL SURFACE
INSTABILITY COULD DEVELOP AS WELL WHICH WOULD POSE AN ADDITIONAL
THUNDER THREAT...ESPECIALLY ALONG THE APPROACHING COLD FRONT WHICH
WILL CROSS THE AREA LATER IN THE DAY. HOWEVER...THE DEEPER DRY AIR
OF THE DRY SLOT MAY PRECLUDE MUCH IF ANY DEVELOPMENT ALONG THE FRONT
IF SURFACE BASED INSTABILITY DOES IN FACT DEVELOP. STILL TOO EARLY
TO HAVE ANY HIGH DEGREE OF CONFIDENCE IN THUNDER POTENTIAL BUT FEEL
THIS BEARS WATCHING GIVEN THE HIGH DEGREE OF DEEP LAYER WIND SHEAR
AND FAIRLY STRONG LOW LEVEL WIND FIELD. HIGH TEMPS SUNDAY LOOK TO
RANGE FROM THE MID 40S NORTHWEST TO THE MID 50S SOUTHEAST.
PRECIP AMOUNTS/FLOODING POTENTIAL...FORECAST GUIDANCE IS IN PRETTY
GOOD AGREEMENT WITH THE TRACK OF LOW LEVEL FEATURES BUT DO DIFFER
IN THE PLACEMENT OF OTHER FEATURES SUCH AS THE PATH OF THE UPPER
JET CORE. QPF OUTPUT DOES DIFFER SOMEWHAT AS A RESULT...ESPECIALLY
IN PLACEMENT OF HEAVIEST VALUES. ARRIVAL TIMING MAY ALSO NEED
ADJUSTMENT WITH SOME GUIDANCE BEING SLOWER BUT RIGHT NOW THE
DIFFERENCES ARE ON THE ORDER OF A FEW HOURS. THE WESTERN AND
NORTHERN CWA CONTINUES TO LOOK TO HAVE THE BEST CHANCE AT
RECEIVING PEAK RAINFALL AMOUNTS...OR ROUGHLY FROM CHICAGO TO
PONTIAC AND POINTS WEST BUT THE ENTIRE CWA DOES LOOK TO SEE
RAINFALL. GIVEN THE PRECIPITABLE WATER VALUES AND DURATION OF
FORCING...AMOUNTS OF 0.75-1.00 INCHES ARE PLAUSIBLE IN THE NORTH
AND WEST WITH LESSER AMOUNTS SOUTHEAST. IF CONVECTION CAN DEVELOP
SUNDAY MORNING THEN AMOUNTS WOULD BE HIGHER IN SPOTS BUT IT IS
POSSIBLE THAT THE BEST CHANCE FOR CONVECTION COULD END UP BEING
ACROSS THE SOUTHERN/EASTERN CWA GIVEN THE LIKELY TRACK OF THE DRY
SLOT AND ARRIVAL OF INSTABILITY. SO CONFIDENCE IN SPECIFIC AMOUNTS
AND WHERE THEY OCCUR IS STILL LIMITED. HOWEVER...EVEN SOMEWHAT
LOWER AMOUNTS THAN THOSE ABOVE ARE STILL A CONCERN GIVEN THE
AMOUNT OF WATER IN THE CURRENT SNOW PACK. REFERENCE HYDROLOGY
SECTION BELOW AND ESFLOT PRODUCT FOR MORE DETAILS.
SUNDAY NIGHT AND MONDAY...TIMING DIFFERENCES BECOME MORE CRITICAL AS
THE SYSTEM DEPARTS SUNDAY NIGHT AND MONDAY. IN TERMS OF FRONTAL
TIMING...THERE IS GOOD AGREEMENT ON HAVING THE COLD FRONT SWEEP
ACROSS THE AREA SUNDAY AFTERNOON WHICH ALLOWS COLDER AIR TO
ARRIVE...BUT THE SPEED WITH WHICH IT ARRIVES IS NOT QUITE CLEAR. THE
ECMWF/GEM REMAIN SLOWER WITH THE PASSAGE OF THE UPPER TROUGH AXIS
DELAYING THE ARRIVAL OF COLDEST AIR...AS WELL AS THE ATTENDANT
DEFORMATION FORCING HOLDING IT OFF UNTIL CLOSER TO MONDAY MORNING.
THE NAM AND GFS ARE FASTER WITH THE UPPER TROUGH AND ARRIVAL OF COLD
AIR. THIS WILL PLAY HAVOC WITH PRECIP TIMING AND TYPE BEHIND THE
FRONT INTO MONDAY MORNING. WILL NEED TO MONITOR THIS PERIOD AS THERE
IS AT LEAST SOME SUPPORT FOR MEASURABLE PRECIP MONDAY.
MDB
LONG TERM...MONDAY NIGHT THROUGH FRIDAY...
THE EXTENDED PERIOD WILL FEATURE A FAIRLY PROGRESSIVE NORTHWEST TO
PERHAPS ZONAL FLOW WITH SEVERAL WEAK SYSTEMS TO AFFECT PART OF THE
REGION/GREAT LAKES. TIMING ANY OF THESE FEATURES IS SOMEWHAT
DIFFICULT AS THEIR STRENGTH/LOCATION CONTINUES TO FLUCTUATE FROM
RUN TO RUN AS WELL AS FROM MODEL TO MODEL. WHILE THERE WILL BE A
FEW CHANCES FOR PRECIP...WILL CONTINUE WITH MAINLY A DRY FORECAST
DUE TO LOW CONFIDENCE THOUGH HAVE INCLUDED A SLIGHT CHANCE OF
SHOWERS ON FRIDAY AS THERE HAS BEEN SOME CONTINUITY DURING THIS TIME
PERIOD. SHOULD PRECIP CHANCES/TRENDS INCREASE...PRECIP TYPE WILL
BECOME A CONCERN DEPENDING ON TIME OF DAY.
TEMPERATURES ARE EQUALLY CHALLENGING...DEPENDING ON THE TIMING OF
THESE FEATURES AND THE EXTENT OF COLD AIR THEY BRING WITH THEM.
ECMWF HAD BEEN FAIRLY CONSISTENT WITH A PUSH OF COLDER AIR THURSDAY
INTO FRIDAY WHICH IS NOW GONE WHILE THE GFS IS NOW MUCH COLDER. HAVE
TRENDED MIDDLE OF THE ROAD WITH TEMPS AND GIVEN MID MARCH SUNSHINE...
LACK OF ANY SIGNIFICANT COLD AIR PUSH WOULD SUPPORT TEMPS NEAR
SEASONAL NORMALS.
CMS
&&
.HYDROLOGY...
234 PM CST
SOME AREAS OF THE FORECAST AREA MAY SEE 0.75-1.00 INCHES
OF RAINFALL FROM SATURDAY THROUGH SUNDAY...WITH THE BULK EXPECTED
SATURDAY EVENING/NIGHT. AT THIS POINT...THESE RAINFALL AMOUNTS ARE
EXPECTED GENERALLY WEST OF A LINE FROM CHICAGO TO PONTIAC WITH
LESSER AMOUNTS SOUTHEAST BUT THERE IS SOME OPPORTUNITY FOR THE
LOCATION TO NEED ADJUSTMENT. IN ADDITION...SOME CONVECTIVE
RAINFALL IS POSSIBLE WHICH COULD RESULT IN LOCALLY HIGHER AMOUNTS.
OBSERVED SNOW CORE WATER EQUIVALENTS RANGE FROM AROUND AN INCH TO
AROUND 2.5 INCHES WHERE THE DEEPEST SNOW EXISTS...MAINLY NORTH OF
INTERSTATE 80. FROST DEPTH REMAINS IN THE 6 TO 10 INCH RANGE. THE
EXPECTATION IS THAT THE SNOW WILL MELT AND RUNOFF WILL BE REALIZED
BEFORE THE FROST MELTS SIGNIFICANTLY DUE TO THE INSULATING
EFFECTS OF THE SNOW PACK. SNOW MELT WILL COMMENCE BEFORE THE BULK
OF THE RAINFALL WHICH COULD ALLOW SOME OF THE RUNOFF INTO AREA
RIVERS AND STREAMS TO MAKE PROGRESS DOWNSTREAM BUT THIS WOULD
LIKELY BE MINIMAL. MOST MELT WILL LIKELY OCCUR WITH THE RAINFALL
SO RIVER RISES WILL OCCUR AND SOME RIVERS COULD EXCEED FLOOD STAGE
LATER SUNDAY/MONDAY. AREAL OVERLAND FLOODING IS A
POSSIBILITY...MAINLY IN LOW LYING AND POORLY DRAINED AREAS.
REFERENCE ESFLOT FOR ADDITIONAL INFORMATION.
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* CHANCE OF SOME LIGHT RAIN THIS AFTERNOON.
* RAIN AND FOG TIMING TONIGHT.
* MVFR CIGS AND VISIBILITY LIKELY AFTER 06 UTC SATURDAY NIGHT.
* IFR CIGS AND VISIBILITY POSSIBLE BY DAYBREAK ON SUNDAY MORNING.
* LLWS POSSIBLE SATURDAY NIGHT.
KJB
//DISCUSSION...UPDATED 06Z...
THE MAIN CONCERNS DURING THE PERIOD WILL BE WITH OUR NEXT STORM
SYSTEM...WHICH IS CURRENTLY TAKING SHAPE ACROSS THE FRONT RANGE OF
THE COLORADO ROCKIES. THIS SYSTEM IS ALREADY TRANSPORTING WARM AND
MOIST AIR NORTHWARD ACROSS THE PLAINS AND INTO THE MID MISSOURI
VALLEY WITH SCATTERED SHOWERS AND EVEN SOME THUNDERSTORMS ONGOING
ACROSS THIS REGION.
IT APPEARS SOME OF THESE SHOWERS MAY EFFECT KRFD AROUND
DAYBREAK...AND WITH TEMPERATURES POSSIBLY NEAR FREEZING...I OPTED TO
LEAVE THE -FZRA IN THE NEW TAF FROM 12-14 UTC THIS MORNING.
HOWEVER...I HAVE LOW CONFIDENCE IN THE FREEZING THREAT AS
TEMPERATURES MAY ACTUALLY JUMP ABOVE FREEZING PRIOR TO THE ONSET OF
THE PRECIPITATION. IN ADDITION...I AM NOT SURE HOW MUCH IF ANY PRECIP
WILL ACTUALLY FALL THIS MORNING. THERE IS STILL SOME DRY AIR IN THE
LOW LEVELS TO OVERCOME...AND IT APPEARS THAT CIGS WILL STILL BE AT
OR ABOVE 9000 FEET THROUGH 15 UTC. WITH THIS IN MIND...WE MAY NOT
SEE MORE THAN A FEW SPRINKLES DURING THE EARLY MORNING HOURS AT
KRFD.
IT APPEARS MOST OF THE DAY PRIOR TO 20 UTC WILL BE DRY. AFTER 20 UTC
WE COULD GET ANOTHER BATCH OF LIGHT RAIN ACROSS THE TAF SITES. THIS
ALSO APPEARS AS THOUGH IT WILL BE RATHER LIGHT...AND I HAVE OPTED TO
KEEP THE PROB 30 GROUP GOING FOR THIS ACTIVITY. I
DID...HOWEVER...TRIM THE END TIME OF THE PROB 30 GROUP TO 01 UTC AS
IT APPEARS THERE WILL BE QUITE A BIT OF DRY TIME THIS EVENING AHEAD
OF THE MAIN BATCH OF RAIN.
RAIN SHOULD ONSET AROUND OR SHORTLY AFTER 03 UTC THIS EVENING AT
KRFD AND AFTER 06 UTC AT THE EASTERN TERMINALS AS THE MAIN STORM
SYSTEM APPROACHES THE AREA. IT APPEARS THE RAIN WILL BE MODERATE AT
TIMES WITH CIGS GRADUALLY LOWERING INTO THE IFR CATEGORY BY EARLY
SUNDAY. VISIBILITIES WILL ALSO BE DEGRADING INTO AT LEAST THE
MVFR RANGE IN RAIN AND FOG. LOW CLOUDS AND FOG LOOK TO CONTINUE INTO
THE DAY ON SUNDAY AS THE SURFACE LOW MOVES OVERHEAD AND SURFACE
DEW POINTS PEAK IN THE LOWER TO MIDDLE 40S.
THERE IS ALSO A CHANCE OF LLWS SATURDAY NIGHT AS IT APPEARS THE A
SOUTHWESTERLY 50-55 LOW LEVEL JET WILL DEVELOP AROUND 2,000 FT AGL.
SURFACE WINDS DURING THIS TIME ARE EXPECTED TO BE AROUND 10 KT OUT
OF THE SOUTH. I HAVE OPTED NOT TO ADD THIS TO THE NEW TAF...BUT IT
MAY NEED TO BE ADDED AT A LATER TIME IF THESE CONDITIONS APPEAR TO BE
SETTING UP.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* LOW CONFIDENCE ON ANY LIGHT RAIN AFFECTING THE TERMINALS THIS
AFTERNOON.
* MEDIUM TO HIGH CONFIDENCE IN RAIN AND FOG REDUCING VISIBILITIES
UNDER 4 MILES LATER SUNDAY NIGHT AFTER 06 UTC.
* MEDIUM CONFIDENCE IN IFR CIGS TOWARDS DAYBREAK SUNDAY.
* LOW TO MEDIUM CONFIDENCE IN LLWS SATURDAY NIGHT.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...RAIN AND FOG WITH LIKELY IFR. A CHANCE FOR A MIX WITH
SNOW DURING THE NIGHT.
MONDAY...SLIGHT CHANCE OF RAIN AND SNOW WITH MVFR.
TUESDAY-THURSDAY...VFR.
MTF
&&
.MARINE...
228 AM CST
A STORM SYSTEM...CURRENTLY TAKING SHAPE ACROSS THE FRONT RANGE OF
THE COLORADO ROCKIES...WILL SPLIT OFF INTO TWO SYSTEMS. ONE WILL
RACE NORTHEASTWARD ACROSS ONTARIO BY SUNDAY...WHILE THE SECOND SYSTEM
MOVES TOWARDS THE SOUTHERN END OF LAKE MICHIGAN BY SUNDAY EVENING.
THIS SECOND SYSTEM LOOKS TO HAVE A LARGE IMPACT ON THE WINDS OVER
THE LAKE THROUGH THE WEEKEND.
SOUTHERLY WINDS WILL OCCUR TODAY AND TONIGHT...UP AROUND 25 KT
AHEAD OF THIS SYSTEM. THEN AS THE SURFACE LOW APPROACHES THE LAKE ON
SUNDAY...THE WINDS WILL BECOME NORTH-NORTHEASTERLY AND INCREASE UP
AROUND 30 KT...ESPECIALLY ACROSS THE NORTHERN END OF THE LAKE.
GALE FORCE WINDS ARE QUITE POSSIBLE WITH THIS SYSTEM...BUT
UNCERTAINTIES REMAIN AS TO THE EXACT TRACK OF THIS SYSTEM...AND
HENCE WHERE THE STRONGEST WINDS WILL BE.
ONCE THIS LOW PASSES OVER THE LAKE...A PERIOD OF NORTHWESTERLY WINDS
OF 25 TO 30 KT LOOKS LIKELY INTO AT LEAST MONDAY. HOWEVER...THESE
NORTHWESTERLY WINDS COULD CONTINUE INTO MIDWEEK AS IT APPEARS A
WEAK CLIPPER SYSTEM MAY MOVE ACROSS THE LAKE SOMETIME ON TUESDAY OR
TUESDAY EVENING.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
229 AM CST SAT MAR 9 2013
.DISCUSSION...
924 PM CST
NO REAL BIG CHANGES TO GOING FORECAST TONIGHT...WITH ONLY MINOR
EDITS TO POP/WX FOR AREAS ACROSS NORTHWEST ILLINOIS.
LATEST SATELLITE IMAGERY DEPICTING MID/UPPER LEVEL CLOUD COVER
CONTINUING TO STREAM NORTHEAST ACROSS THE REGION THIS EVENING...AS
SOUTHWESTERLY FLOW CONTINUES OUT AHEAD OF AN APPROACHING LONGWAVE
TROUGH OVER THE WESTERN CONUS. THIS IS USHERING IN A WARMER AND
MORE MOIST ENVIRONMENT WITH LATEST RAP ANALYSIS DEPICTING STRONG
WAA OCCURRING ACROSS MUCH OF THE PLAINS...AND CAN BE NOTED VIA THE
ABUNDANCE OF CLOUD COVER AS WELL AS THE WIDESPREAD PRECIP SHIELD
IN THIS LOCATION. ALTHOUGH THE STRONGEST WAA WILL REMAIN JUST TO
THE WEST OF THE CWA...LATEST SHORT TERM GUIDANCE IS INDICATING
THAT SOME LIGHT PRECIP DEVELOPMENT COULD OCCUR ACROSS NORTHWEST
ILLINOIS TONIGHT AS THIS WAA WING CONTINUES TO LIFT
NORTH/NORTHEAST. PRECIP DEVELOPMENT LATE TONIGHT ACROSS AREAS
ALONG AND WEST OF INTERSTATE 39 DOES SEEM REASONABLE WITH THIS
BETTER FORCING ALREADY INCHING CLOSER TO THE CWA. ALTHOUGH THIS
FORCING WILL REMAIN RATHER WEAK...IT MAY BE ENOUGH OF A PERSISTENT
FEATURE TO OVERCOME SOME DRIER AIR IN PLACE. THERMAL PROFILES WILL
SUPPORT PRECIP OF THE LIQUID TYPE...BUT WITH THE POSSIBILITY OF A
BRIEF WINDOW OF LIGHT FREEZING RAIN. ALTHOUGH...WARMING TONIGHT
SHOULD MITIGATE ANY OVERALL FREEZING RAIN POTENTIAL WITH SURFACE
TEMPERATURES EXPECTED TO BE HOVERING AROUND FREEZING IF NOT
BEGINNING TO RISE JUST ABOVE BY THE TIME THIS PRECIP ARRIVES. SO
HAVE MADE MENTION OF A SLIGHT CHANCE OF LIGHT RAIN/LIGHT FREEZING
RAIN FOR LATE TONIGHT INTO EARLY SATURDAY MORNING BEFORE
TEMPERATURES CONTINUE TO RISE THROUGH MID SATURDAY MORNING WITH
ONLY RAIN THEN EXPECTED.
RODRIGUEZ
//PREV DISCUSSION...
234 PM CST
THE AREA WILL QUICKLY SHIFT FROM WINTER TO SPRING WEATHER THIS
WEEKEND WITH EXPECTED RAINFALL/SNOW MELT WITH WARMING TEMPERATURES
POSING A FLOOD THREAT...WITH THUNDERSTORMS NOT OUT OF THE QUESTION
BY SUNDAY. UPS AND DOWNS IN TEMPERATURES ARE EXPECTED NEXT WEEK WITH
A SERIES OF WEAKER SYSTEMS BRINGING PERIODIC LOW CHANCES FOR
PRECIPITATION.
SYNOPSIS...EARLY AFTERNOON WATER VAPOR IMAGERY SHOWS UPPER RIDGING
BUILDING ACROSS THE MISSISSIPPI RIVER VALLEY INTO THE LOCAL AREA IN
RESPONSE TO A DEEP CLOSED UPPER LOW ROTATING INTO THE DESERT
SOUTHWEST. THIS TROUGH IS SPLIT FROM A TROUGH THAT IS POSITIONED
OVER CENTRAL CANADA WITH A TROUGH AXIS SHIFTING TOWARDS WESTERN
SASKATCHEWAN. THESE TWO FEATURES WILL BE THE MAIN DRIVERS OF
EXPECTED RAINFALL THIS WEEKEND. AT THE SURFACE...A LARGE AREA OF
HIGH PRESSURE IS EXITING THE LOCAL AREA TO THE EAST. WEAK LOW
PRESSURE IS OVER SOUTHERN MANITOBA AND IS DRIFTING EASTWARD.
TONIGHT AND SATURDAY...QUIET WEATHER WILL CONTINUE TONIGHT WITH THE
UPPER RIDGE CRESTING THE AREA THIS EVENING. THE BIG SOUTHWEST
TROUGH WILL BE MOVING EASTWARD WITH HEIGHT FALLS AHEAD OF IT AND
BEHIND THE RIDGE ALLOWING LOW PRESSURE TO DEVELOP IN THE LEE OF
THE ROCKIES. A 50+KT LOW LEVEL JET WILL SET UP ACROSS THE PLAINS
RESULTING IN A STRONG PUSH OF HIGH THETA-E LOW LEVEL AIR ACROSS
THE SOUTHERN AND CENTRAL PLAINS. HIGH LEVEL MOISTURE WILL BE
SPREAD NORTHEASTWARD SUPPORTING AN INCREASE IN MID AND HIGH LEVEL
CLOUD COVER OVERNIGHT. THE PRESSURE GRADIENT WILL BE WEAK ACROSS
THE AREA EARLY BUT WILL TIGHTEN OVERNIGHT SO WINDS MAY DROP OFF
FOR A TIME EARLY BEFORE INCREASING SOMEWHAT OVERNIGHT. LOW TEMPS
WILL BE THE MAIN CHALLENGE AND MAY OCCUR DURING THE EVENING BUT
SOME WARMING MAY OCCUR LATE AS CLOUDS AND WINDS INCREASE AND WARM
ADVECTION IS UNDERWAY ALOFT. WILL GO AHEAD AND SHOW A STEADY OR
WARMING TREND OVERNIGHT. LIGHT PRECIP BECOMES A CONCERN BY
SATURDAY MORNING AS WAVES OF WARM ADVECTION BECOME MORE FOCUSED
AND MOISTURE DEEPENS. THIS IS WHERE TEMPS WILL BECOME CRITICAL
BECAUSE CHANCES FOR LIGHT PRECIP MAY BEGIN EARLY ENOUGH TO FALL AS
FREEZING RAIN. SIGNALS FOR PRECIP ARE NOT ALL THAT ORGANIZED UNTIL
SATURDAY AFTERNOON BUT WESTERN AREAS MAY HAVE DEEP ENOUGH MOISTURE
AND ENOUGH WARM ASCENT OCCURRING ALOFT TO SEE LIGHT RAIN...OR
FREEZING RAIN IF TEMPS START OUT BELOW FREEZING...BY LATE SATURDAY
MORNING. ANY FREEZING PRECIP WILL QUICKLY END AS TEMPS WARM WELL
ABOVE FREEZING BY EARLY AFTERNOON. PRECIP CHANCES WILL THEN EXPAND
EASTWARD...ESPECIALLY ACROSS THE NORTHERN CWA SATURDAY AFTERNOON
BUT CHANCES STILL LOOK RATHER LOW BUT STILL WORTH A MENTION GIVEN
STEADILY INCREASING DEEP LAYER MOISTURE /PRECIPITABLE WATER VALUES
REACH 0.75 INCHES OR SO BY LATE DAY/ AND WARM ADVECTION. SOUTH TO
SOUTHEAST WINDS WILL BECOME BREEZY WHICH WILL HELP HIGHS WARM INTO
LOW TO MID 40S NORTH AND MID TO UPPER 40S SOUTH. IT IS ALSO
IMPORTANT TO NOTE THAT DEW POINTS WILL BE ON THE RISE AS WELL
WHICH WILL COMBINE WITH THE STEADY WINDS AND MILD TEMPS TO PROVIDE
INCREASINGLY EFFICIENT SNOW MELT THROUGH THE AFTERNOON. MORE ON
THIS BELOW...
SATURDAY NIGHT AND SUNDAY...THE SOUTHWEST UPPER LOW WILL BE
LIFTING ACROSS THE SOUTHERN HIGH PLAINS AND PHASING WITH THE CENTRAL
CANADA UPPER TROUGH WHICH WILL BE SHARPENING AS IT PIVOTS
SOUTHEASTWARD. THE MAIN SURFACE LOW IS EXPECTED TO ORGANIZE IN
VICINITY OF THE SOUTHERN UPPER LOW ACROSS WESTERN KANSAS BY SATURDAY
EVENING WITH AN INVERTED TROUGH EXTENDING NORTHWARD INTO WESTERN
ONTARIO. GULF MOISTURE WILL CONTINUE TO STREAM NORTHWARD AHEAD OF
THE LOW AS 60KT LOW LEVEL JET SPREADS ACROSS
MISSOURI...ILLINOIS...AND LAKE MICHIGAN LATER SATURDAY EVENING.
PRECIPITABLE WATER VALUES WILL FURTHER SURGE REACHING THE 1 TO
PERHAPS 1.25 INCH RANGE WHICH WILL COMBINE WITH INCREASED ASCENT TO
PRODUCE WIDESPREAD RAIN ACROSS THE MID-MISSISSIPPI RIVER VALLEY
WHICH WILL THEN SPREAD EASTWARD DURING THE EVENING AND OVERNIGHT
HOURS. THE UPPER LOW WILL BE TO THE WEST OF THE AREA BY SUNDAY
MORNING WHICH WILL LIKELY BRING A DRY SLOT INTO THE AREA SOMETIME
SUNDAY MORNING. INSTABILITY DOES INCREASE AS WELL...POTENTIALLY WITH
ENOUGH ELEVATED INSTABILITY TO SUPPORT SOME THUNDER POTENTIAL ON THE
LEADING EDGE OF THE DRY SLOT. FURTHERMORE...SOME MINIMAL SURFACE
INSTABILITY COULD DEVELOP AS WELL WHICH WOULD POSE AN ADDITIONAL
THUNDER THREAT...ESPECIALLY ALONG THE APPROACHING COLD FRONT WHICH
WILL CROSS THE AREA LATER IN THE DAY. HOWEVER...THE DEEPER DRY AIR
OF THE DRY SLOT MAY PRECLUDE MUCH IF ANY DEVELOPMENT ALONG THE FRONT
IF SURFACE BASED INSTABILITY DOES IN FACT DEVELOP. STILL TOO EARLY
TO HAVE ANY HIGH DEGREE OF CONFIDENCE IN THUNDER POTENTIAL BUT FEEL
THIS BEARS WATCHING GIVEN THE HIGH DEGREE OF DEEP LAYER WIND SHEAR
AND FAIRLY STRONG LOW LEVEL WIND FIELD. HIGH TEMPS SUNDAY LOOK TO
RANGE FROM THE MID 40S NORTHWEST TO THE MID 50S SOUTHEAST.
PRECIP AMOUNTS/FLOODING POTENTIAL...FORECAST GUIDANCE IS IN PRETTY
GOOD AGREEMENT WITH THE TRACK OF LOW LEVEL FEATURES BUT DO DIFFER
IN THE PLACEMENT OF OTHER FEATURES SUCH AS THE PATH OF THE UPPER
JET CORE. QPF OUTPUT DOES DIFFER SOMEWHAT AS A RESULT...ESPECIALLY
IN PLACEMENT OF HEAVIEST VALUES. ARRIVAL TIMING MAY ALSO NEED
ADJUSTMENT WITH SOME GUIDANCE BEING SLOWER BUT RIGHT NOW THE
DIFFERENCES ARE ON THE ORDER OF A FEW HOURS. THE WESTERN AND
NORTHERN CWA CONTINUES TO LOOK TO HAVE THE BEST CHANCE AT
RECEIVING PEAK RAINFALL AMOUNTS...OR ROUGHLY FROM CHICAGO TO
PONTIAC AND POINTS WEST BUT THE ENTIRE CWA DOES LOOK TO SEE
RAINFALL. GIVEN THE PRECIPITABLE WATER VALUES AND DURATION OF
FORCING...AMOUNTS OF 0.75-1.00 INCHES ARE PLAUSIBLE IN THE NORTH
AND WEST WITH LESSER AMOUNTS SOUTHEAST. IF CONVECTION CAN DEVELOP
SUNDAY MORNING THEN AMOUNTS WOULD BE HIGHER IN SPOTS BUT IT IS
POSSIBLE THAT THE BEST CHANCE FOR CONVECTION COULD END UP BEING
ACROSS THE SOUTHERN/EASTERN CWA GIVEN THE LIKELY TRACK OF THE DRY
SLOT AND ARRIVAL OF INSTABILITY. SO CONFIDENCE IN SPECIFIC AMOUNTS
AND WHERE THEY OCCUR IS STILL LIMITED. HOWEVER...EVEN SOMEWHAT
LOWER AMOUNTS THAN THOSE ABOVE ARE STILL A CONCERN GIVEN THE
AMOUNT OF WATER IN THE CURRENT SNOW PACK. REFERENCE HYDROLOGY
SECTION BELOW AND ESFLOT PRODUCT FOR MORE DETAILS.
SUNDAY NIGHT AND MONDAY...TIMING DIFFERENCES BECOME MORE CRITICAL AS
THE SYSTEM DEPARTS SUNDAY NIGHT AND MONDAY. IN TERMS OF FRONTAL
TIMING...THERE IS GOOD AGREEMENT ON HAVING THE COLD FRONT SWEEP
ACROSS THE AREA SUNDAY AFTERNOON WHICH ALLOWS COLDER AIR TO
ARRIVE...BUT THE SPEED WITH WHICH IT ARRIVES IS NOT QUITE CLEAR. THE
ECMWF/GEM REMAIN SLOWER WITH THE PASSAGE OF THE UPPER TROUGH AXIS
DELAYING THE ARRIVAL OF COLDEST AIR...AS WELL AS THE ATTENDANT
DEFORMATION FORCING HOLDING IT OFF UNTIL CLOSER TO MONDAY MORNING.
THE NAM AND GFS ARE FASTER WITH THE UPPER TROUGH AND ARRIVAL OF COLD
AIR. THIS WILL PLAY HAVOC WITH PRECIP TIMING AND TYPE BEHIND THE
FRONT INTO MONDAY MORNING. WILL NEED TO MONITOR THIS PERIOD AS THERE
IS AT LEAST SOME SUPPORT FOR MEASURABLE PRECIP MONDAY.
MDB
LONG TERM...MONDAY NIGHT THROUGH FRIDAY...
THE EXTENDED PERIOD WILL FEATURE A FAIRLY PROGRESSIVE NORTHWEST TO
PERHAPS ZONAL FLOW WITH SEVERAL WEAK SYSTEMS TO AFFECT PART OF THE
REGION/GREAT LAKES. TIMING ANY OF THESE FEATURES IS SOMEWHAT
DIFFICULT AS THEIR STRENGTH/LOCATION CONTINUES TO FLUCTUATE FROM
RUN TO RUN AS WELL AS FROM MODEL TO MODEL. WHILE THERE WILL BE A
FEW CHANCES FOR PRECIP...WILL CONTINUE WITH MAINLY A DRY FORECAST
DUE TO LOW CONFIDENCE THOUGH HAVE INCLUDED A SLIGHT CHANCE OF
SHOWERS ON FRIDAY AS THERE HAS BEEN SOME CONTINUITY DURING THIS TIME
PERIOD. SHOULD PRECIP CHANCES/TRENDS INCREASE...PRECIP TYPE WILL
BECOME A CONCERN DEPENDING ON TIME OF DAY.
TEMPERATURES ARE EQUALLY CHALLENGING...DEPENDING ON THE TIMING OF
THESE FEATURES AND THE EXTENT OF COLD AIR THEY BRING WITH THEM.
ECMWF HAD BEEN FAIRLY CONSISTENT WITH A PUSH OF COLDER AIR THURSDAY
INTO FRIDAY WHICH IS NOW GONE WHILE THE GFS IS NOW MUCH COLDER. HAVE
TRENDED MIDDLE OF THE ROAD WITH TEMPS AND GIVEN MID MARCH SUNSHINE...
LACK OF ANY SIGNIFICANT COLD AIR PUSH WOULD SUPPORT TEMPS NEAR
SEASONAL NORMALS.
CMS
&&
.HYDROLOGY...
234 PM CST
SOME AREAS OF THE FORECAST AREA MAY SEE 0.75-1.00 INCHES
OF RAINFALL FROM SATURDAY THROUGH SUNDAY...WITH THE BULK EXPECTED
SATURDAY EVENING/NIGHT. AT THIS POINT...THESE RAINFALL AMOUNTS ARE
EXPECTED GENERALLY WEST OF A LINE FROM CHICAGO TO PONTIAC WITH
LESSER AMOUNTS SOUTHEAST BUT THERE IS SOME OPPORTUNITY FOR THE
LOCATION TO NEED ADJUSTMENT. IN ADDITION...SOME CONVECTIVE
RAINFALL IS POSSIBLE WHICH COULD RESULT IN LOCALLY HIGHER AMOUNTS.
OBSERVED SNOW CORE WATER EQUIVALENTS RANGE FROM AROUND AN INCH TO
AROUND 2.5 INCHES WHERE THE DEEPEST SNOW EXISTS...MAINLY NORTH OF
INTERSTATE 80. FROST DEPTH REMAINS IN THE 6 TO 10 INCH RANGE. THE
EXPECTATION IS THAT THE SNOW WILL MELT AND RUNOFF WILL BE REALIZED
BEFORE THE FROST MELTS SIGNIFICANTLY DUE TO THE INSULATING
EFFECTS OF THE SNOW PACK. SNOW MELT WILL COMMENCE BEFORE THE BULK
OF THE RAINFALL WHICH COULD ALLOW SOME OF THE RUNOFF INTO AREA
RIVERS AND STREAMS TO MAKE PROGRESS DOWNSTREAM BUT THIS WOULD
LIKELY BE MINIMAL. MOST MELT WILL LIKELY OCCUR WITH THE RAINFALL
SO RIVER RISES WILL OCCUR AND SOME RIVERS COULD EXCEED FLOOD STAGE
LATER SUNDAY/MONDAY. AREAL OVERLAND FLOODING IS A
POSSIBILITY...MAINLY IN LOW LYING AND POORLY DRAINED AREAS.
REFERENCE ESFLOT FOR ADDITIONAL INFORMATION.
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* CHANCE OF SOME LIGHT RAIN THIS AFTERNOON.
* RAIN AND FOG TIMING TONIGHT.
* MVFR CIGS AND VISIBILITY LIKELY AFTER 06 UTC SATURDAY NIGHT.
* IFR CIGS AND VISIBILITY POSSIBLE BY DAYBREAK ON SUNDAY MORNING.
* LLWS POSSIBLE SATURDAY NIGHT.
KJB
//DISCUSSION...UPDATED 06Z...
THE MAIN CONCERNS DURING THE PERIOD WILL BE WITH OUR NEXT STORM
SYSTEM...WHICH IS CURRENTLY TAKING SHAPE ACROSS THE FRONT RANGE OF
THE COLORADO ROCKIES. THIS SYSTEM IS ALREADY TRANSPORTING WARM AND
MOIST AIR NORTHWARD ACROSS THE PLAINS AND INTO THE MID MISSOURI
VALLEY WITH SCATTERED SHOWERS AND EVEN SOME THUNDERSTORMS ONGOING
ACROSS THIS REGION.
IT APPEARS SOME OF THESE SHOWERS MAY EFFECT KRFD AROUND
DAYBREAK...AND WITH TEMPERATURES POSSIBLY NEAR FREEZING...I OPTED TO
LEAVE THE -FZRA IN THE NEW TAF FROM 12-14 UTC THIS MORNING.
HOWEVER...I HAVE LOW CONFIDENCE IN THE FREEZING THREAT AS
TEMPERATURES MAY ACTUALLY JUMP ABOVE FREEZING PRIOR TO THE ONSET OF
THE PRECIPITATION. IN ADDITION...I AM NOT SURE HOW MUCH IF ANY PRECIP
WILL ACTUALLY FALL THIS MORNING. THERE IS STILL SOME DRY AIR IN THE
LOW LEVELS TO OVERCOME...AND IT APPEARS THAT CIGS WILL STILL BE AT
OR ABOVE 9000 FEET THROUGH 15 UTC. WITH THIS IN MIND...WE MAY NOT
SEE MORE THAN A FEW SPRINKLES DURING THE EARLY MORNING HOURS AT
KRFD.
IT APPEARS MOST OF THE DAY PRIOR TO 20 UTC WILL BE DRY. AFTER 20 UTC
WE COULD GET ANOTHER BATCH OF LIGHT RAIN ACROSS THE TAF SITES. THIS
ALSO APPEARS AS THOUGH IT WILL BE RATHER LIGHT...AND I HAVE OPTED TO
KEEP THE PROB 30 GROUP GOING FOR THIS ACTIVITY. I
DID...HOWEVER...TRIM THE END TIME OF THE PROB 30 GROUP TO 01 UTC AS
IT APPEARS THERE WILL BE QUITE A BIT OF DRY TIME THIS EVENING AHEAD
OF THE MAIN BATCH OF RAIN.
RAIN SHOULD ONSET AROUND OR SHORTLY AFTER 03 UTC THIS EVENING AT
KRFD AND AFTER 06 UTC AT THE EASTERN TERMINALS AS THE MAIN STORM
SYSTEM APPROACHES THE AREA. IT APPEARS THE RAIN WILL BE MODERATE AT
TIMES WITH CIGS GRADUALLY LOWERING INTO THE IFR CATEGORY BY EARLY
SUNDAY. VISIBILITIES WILL ALSO BE DEGRADING INTO AT LEAST THE
MVFR RANGE IN RAIN AND FOG. LOW CLOUDS AND FOG LOOK TO CONTINUE INTO
THE DAY ON SUNDAY AS THE SURFACE LOW MOVES OVERHEAD AND SURFACE
DEW POINTS PEAK IN THE LOWER TO MIDDLE 40S.
THERE IS ALSO A CHANCE OF LLWS SATURDAY NIGHT AS IT APPEARS THE A
SOUTHWESTERLY 50-55 LOW LEVEL JET WILL DEVELOP AROUND 2,000 FT AGL.
SURFACE WINDS DURING THIS TIME ARE EXPECTED TO BE AROUND 10 KT OUT
OF THE SOUTH. I HAVE OPTED NOT TO ADD THIS TO THE NEW TAF...BUT IT
MAY NEED TO BE ADDED AT A LATER TIME IF THESE CONDITIONS APPEAR TO BE
SETTING UP.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW CONFIDENCE ON ANY LIGHT RAIN AFFECTING THE TERMINALS THIS
AFTERNOON.
* MEDIUM TO HIGH CONFIDENCE IN RAIN AND FOG REDUCING VISIBILITIES
UNDER 4 MILES LATER SUNDAY NIGHT AFTER 06 UTC.
* MEDIUM CONFIDENCE IN IFR CIGS TOWARDS DAYBREAK SUNDAY.
* LOW TO MEDIUM CONFIDENCE IN LLWS SATURDAY NIGHT.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...RAIN AND FOG WITH LIKELY IFR. A CHANCE FOR A MIX WITH
SNOW DURING THE NIGHT.
MONDAY...SLIGHT CHANCE OF RAIN AND SNOW WITH MVFR.
TUESDAY-THURSDAY...VFR.
MTF
&&
.MARINE...
228 AM CST
A STORM SYSTEM...CURRENTLY TAKING SHAPE ACROSS THE FRONT RANGE OF
THE COLORADO ROCKIES...WILL SPLIT OFF INTO TWO SYSTEMS. ONE WILL
RACE NORTHEASTWARD ACROSS ONTARIO BY SUNDAY...WHILE THE SECOND SYSTEM
MOVES TOWARDS THE SOUTHERN END OF LAKE MICHIGAN BY SUNDAY EVENING.
THIS SECOND SYSTEM LOOKS TO HAVE A LARGE IMPACT ON THE WINDS OVER
THE LAKE THROUGH THE WEEKEND.
SOUTHERLY WINDS WILL OCCUR TODAY AND TONIGHT...UP AROUND 25 KT
AHEAD OF THIS SYSTEM. THEN AS THE SURFACE LOW APPROACHES THE LAKE ON
SUNDAY...THE WINDS WILL BECOME NORTH-NORTHEASTERLY AND INCREASE UP
AROUND 30 KT...ESPECIALLY ACROSS THE NORTHERN END OF THE LAKE.
GALE FORCE WINDS ARE QUITE POSSIBLE WITH THIS SYSTEM...BUT
UNCERTAINTIES REMAIN AS TO THE EXACT TRACK OF THIS SYSTEM...AND
HENCE WHERE THE STRONGEST WINDS WILL BE.
ONCE THIS LOW PASSES OVER THE LAKE...A PERIOD OF NORTHWESTERLY WINDS
OF 25 TO 30 KT LOOKS LIKELY INTO AT LEAST MONDAY. HOWEVER...THESE
NORTHWESTERLY WINDS COULD CONTINUE INTO MIDWEEK AS IT APPEARS A
WEAK CLIPPER SYSTEM MAY MOVE ACROSS THE LAKE SOMETIME ON TUESDAY OR
TUESDAY EVENING.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1227 AM CST SAT MAR 9 2013
.DISCUSSION...
924 PM CST
NO REAL BIG CHANGES TO GOING FORECAST TONIGHT...WITH ONLY MINOR
EDITS TO POP/WX FOR AREAS ACROSS NORTHWEST ILLINOIS.
LATEST SATELLITE IMAGERY DEPICTING MID/UPPER LEVEL CLOUD COVER
CONTINUING TO STREAM NORTHEAST ACROSS THE REGION THIS EVENING...AS
SOUTHWESTERLY FLOW CONTINUES OUT AHEAD OF AN APPROACHING LONGWAVE
TROUGH OVER THE WESTERN CONUS. THIS IS USHERING IN A WARMER AND
MORE MOIST ENVIRONMENT WITH LATEST RAP ANALYSIS DEPICTING STRONG
WAA OCCURRING ACROSS MUCH OF THE PLAINS...AND CAN BE NOTED VIA THE
ABUNDANCE OF CLOUD COVER AS WELL AS THE WIDESPREAD PRECIP SHIELD
IN THIS LOCATION. ALTHOUGH THE STRONGEST WAA WILL REMAIN JUST TO
THE WEST OF THE CWA...LATEST SHORT TERM GUIDANCE IS INDICATING
THAT SOME LIGHT PRECIP DEVELOPMENT COULD OCCUR ACROSS NORTHWEST
ILLINOIS TONIGHT AS THIS WAA WING CONTINUES TO LIFT
NORTH/NORTHEAST. PRECIP DEVELOPMENT LATE TONIGHT ACROSS AREAS
ALONG AND WEST OF INTERSTATE 39 DOES SEEM REASONABLE WITH THIS
BETTER FORCING ALREADY INCHING CLOSER TO THE CWA. ALTHOUGH THIS
FORCING WILL REMAIN RATHER WEAK...IT MAY BE ENOUGH OF A PERSISTENT
FEATURE TO OVERCOME SOME DRIER AIR IN PLACE. THERMAL PROFILES WILL
SUPPORT PRECIP OF THE LIQUID TYPE...BUT WITH THE POSSIBILITY OF A
BRIEF WINDOW OF LIGHT FREEZING RAIN. ALTHOUGH...WARMING TONIGHT
SHOULD MITIGATE ANY OVERALL FREEZING RAIN POTENTIAL WITH SURFACE
TEMPERATURES EXPECTED TO BE HOVERING AROUND FREEZING IF NOT
BEGINNING TO RISE JUST ABOVE BY THE TIME THIS PRECIP ARRIVES. SO
HAVE MADE MENTION OF A SLIGHT CHANCE OF LIGHT RAIN/LIGHT FREEZING
RAIN FOR LATE TONIGHT INTO EARLY SATURDAY MORNING BEFORE
TEMPERATURES CONTINUE TO RISE THROUGH MID SATURDAY MORNING WITH
ONLY RAIN THEN EXPECTED.
RODRIGUEZ
//PREV DISCUSSION...
234 PM CST
THE AREA WILL QUICKLY SHIFT FROM WINTER TO SPRING WEATHER THIS
WEEKEND WITH EXPECTED RAINFALL/SNOW MELT WITH WARMING TEMPERATURES
POSING A FLOOD THREAT...WITH THUNDERSTORMS NOT OUT OF THE QUESTION
BY SUNDAY. UPS AND DOWNS IN TEMPERATURES ARE EXPECTED NEXT WEEK WITH
A SERIES OF WEAKER SYSTEMS BRINGING PERIODIC LOW CHANCES FOR
PRECIPITATION.
SYNOPSIS...EARLY AFTERNOON WATER VAPOR IMAGERY SHOWS UPPER RIDGING
BUILDING ACROSS THE MISSISSIPPI RIVER VALLEY INTO THE LOCAL AREA IN
RESPONSE TO A DEEP CLOSED UPPER LOW ROTATING INTO THE DESERT
SOUTHWEST. THIS TROUGH IS SPLIT FROM A TROUGH THAT IS POSITIONED
OVER CENTRAL CANADA WITH A TROUGH AXIS SHIFTING TOWARDS WESTERN
SASKATCHEWAN. THESE TWO FEATURES WILL BE THE MAIN DRIVERS OF
EXPECTED RAINFALL THIS WEEKEND. AT THE SURFACE...A LARGE AREA OF
HIGH PRESSURE IS EXITING THE LOCAL AREA TO THE EAST. WEAK LOW
PRESSURE IS OVER SOUTHERN MANITOBA AND IS DRIFTING EASTWARD.
TONIGHT AND SATURDAY...QUIET WEATHER WILL CONTINUE TONIGHT WITH THE
UPPER RIDGE CRESTING THE AREA THIS EVENING. THE BIG SOUTHWEST
TROUGH WILL BE MOVING EASTWARD WITH HEIGHT FALLS AHEAD OF IT AND
BEHIND THE RIDGE ALLOWING LOW PRESSURE TO DEVELOP IN THE LEE OF
THE ROCKIES. A 50+KT LOW LEVEL JET WILL SET UP ACROSS THE PLAINS
RESULTING IN A STRONG PUSH OF HIGH THETA-E LOW LEVEL AIR ACROSS
THE SOUTHERN AND CENTRAL PLAINS. HIGH LEVEL MOISTURE WILL BE
SPREAD NORTHEASTWARD SUPPORTING AN INCREASE IN MID AND HIGH LEVEL
CLOUD COVER OVERNIGHT. THE PRESSURE GRADIENT WILL BE WEAK ACROSS
THE AREA EARLY BUT WILL TIGHTEN OVERNIGHT SO WINDS MAY DROP OFF
FOR A TIME EARLY BEFORE INCREASING SOMEWHAT OVERNIGHT. LOW TEMPS
WILL BE THE MAIN CHALLENGE AND MAY OCCUR DURING THE EVENING BUT
SOME WARMING MAY OCCUR LATE AS CLOUDS AND WINDS INCREASE AND WARM
ADVECTION IS UNDERWAY ALOFT. WILL GO AHEAD AND SHOW A STEADY OR
WARMING TREND OVERNIGHT. LIGHT PRECIP BECOMES A CONCERN BY
SATURDAY MORNING AS WAVES OF WARM ADVECTION BECOME MORE FOCUSED
AND MOISTURE DEEPENS. THIS IS WHERE TEMPS WILL BECOME CRITICAL
BECAUSE CHANCES FOR LIGHT PRECIP MAY BEGIN EARLY ENOUGH TO FALL AS
FREEZING RAIN. SIGNALS FOR PRECIP ARE NOT ALL THAT ORGANIZED UNTIL
SATURDAY AFTERNOON BUT WESTERN AREAS MAY HAVE DEEP ENOUGH MOISTURE
AND ENOUGH WARM ASCENT OCCURRING ALOFT TO SEE LIGHT RAIN...OR
FREEZING RAIN IF TEMPS START OUT BELOW FREEZING...BY LATE SATURDAY
MORNING. ANY FREEZING PRECIP WILL QUICKLY END AS TEMPS WARM WELL
ABOVE FREEZING BY EARLY AFTERNOON. PRECIP CHANCES WILL THEN EXPAND
EASTWARD...ESPECIALLY ACROSS THE NORTHERN CWA SATURDAY AFTERNOON
BUT CHANCES STILL LOOK RATHER LOW BUT STILL WORTH A MENTION GIVEN
STEADILY INCREASING DEEP LAYER MOISTURE /PRECIPITABLE WATER VALUES
REACH 0.75 INCHES OR SO BY LATE DAY/ AND WARM ADVECTION. SOUTH TO
SOUTHEAST WINDS WILL BECOME BREEZY WHICH WILL HELP HIGHS WARM INTO
LOW TO MID 40S NORTH AND MID TO UPPER 40S SOUTH. IT IS ALSO
IMPORTANT TO NOTE THAT DEW POINTS WILL BE ON THE RISE AS WELL
WHICH WILL COMBINE WITH THE STEADY WINDS AND MILD TEMPS TO PROVIDE
INCREASINGLY EFFICIENT SNOW MELT THROUGH THE AFTERNOON. MORE ON
THIS BELOW...
SATURDAY NIGHT AND SUNDAY...THE SOUTHWEST UPPER LOW WILL BE
LIFTING ACROSS THE SOUTHERN HIGH PLAINS AND PHASING WITH THE CENTRAL
CANADA UPPER TROUGH WHICH WILL BE SHARPENING AS IT PIVOTS
SOUTHEASTWARD. THE MAIN SURFACE LOW IS EXPECTED TO ORGANIZE IN
VICINITY OF THE SOUTHERN UPPER LOW ACROSS WESTERN KANSAS BY SATURDAY
EVENING WITH AN INVERTED TROUGH EXTENDING NORTHWARD INTO WESTERN
ONTARIO. GULF MOISTURE WILL CONTINUE TO STREAM NORTHWARD AHEAD OF
THE LOW AS 60KT LOW LEVEL JET SPREADS ACROSS
MISSOURI...ILLINOIS...AND LAKE MICHIGAN LATER SATURDAY EVENING.
PRECIPITABLE WATER VALUES WILL FURTHER SURGE REACHING THE 1 TO
PERHAPS 1.25 INCH RANGE WHICH WILL COMBINE WITH INCREASED ASCENT TO
PRODUCE WIDESPREAD RAIN ACROSS THE MID-MISSISSIPPI RIVER VALLEY
WHICH WILL THEN SPREAD EASTWARD DURING THE EVENING AND OVERNIGHT
HOURS. THE UPPER LOW WILL BE TO THE WEST OF THE AREA BY SUNDAY
MORNING WHICH WILL LIKELY BRING A DRY SLOT INTO THE AREA SOMETIME
SUNDAY MORNING. INSTABILITY DOES INCREASE AS WELL...POTENTIALLY WITH
ENOUGH ELEVATED INSTABILITY TO SUPPORT SOME THUNDER POTENTIAL ON THE
LEADING EDGE OF THE DRY SLOT. FURTHERMORE...SOME MINIMAL SURFACE
INSTABILITY COULD DEVELOP AS WELL WHICH WOULD POSE AN ADDITIONAL
THUNDER THREAT...ESPECIALLY ALONG THE APPROACHING COLD FRONT WHICH
WILL CROSS THE AREA LATER IN THE DAY. HOWEVER...THE DEEPER DRY AIR
OF THE DRY SLOT MAY PRECLUDE MUCH IF ANY DEVELOPMENT ALONG THE FRONT
IF SURFACE BASED INSTABILITY DOES IN FACT DEVELOP. STILL TOO EARLY
TO HAVE ANY HIGH DEGREE OF CONFIDENCE IN THUNDER POTENTIAL BUT FEEL
THIS BEARS WATCHING GIVEN THE HIGH DEGREE OF DEEP LAYER WIND SHEAR
AND FAIRLY STRONG LOW LEVEL WIND FIELD. HIGH TEMPS SUNDAY LOOK TO
RANGE FROM THE MID 40S NORTHWEST TO THE MID 50S SOUTHEAST.
PRECIP AMOUNTS/FLOODING POTENTIAL...FORECAST GUIDANCE IS IN PRETTY
GOOD AGREEMENT WITH THE TRACK OF LOW LEVEL FEATURES BUT DO DIFFER
IN THE PLACEMENT OF OTHER FEATURES SUCH AS THE PATH OF THE UPPER
JET CORE. QPF OUTPUT DOES DIFFER SOMEWHAT AS A RESULT...ESPECIALLY
IN PLACEMENT OF HEAVIEST VALUES. ARRIVAL TIMING MAY ALSO NEED
ADJUSTMENT WITH SOME GUIDANCE BEING SLOWER BUT RIGHT NOW THE
DIFFERENCES ARE ON THE ORDER OF A FEW HOURS. THE WESTERN AND
NORTHERN CWA CONTINUES TO LOOK TO HAVE THE BEST CHANCE AT
RECEIVING PEAK RAINFALL AMOUNTS...OR ROUGHLY FROM CHICAGO TO
PONTIAC AND POINTS WEST BUT THE ENTIRE CWA DOES LOOK TO SEE
RAINFALL. GIVEN THE PRECIPITABLE WATER VALUES AND DURATION OF
FORCING...AMOUNTS OF 0.75-1.00 INCHES ARE PLAUSIBLE IN THE NORTH
AND WEST WITH LESSER AMOUNTS SOUTHEAST. IF CONVECTION CAN DEVELOP
SUNDAY MORNING THEN AMOUNTS WOULD BE HIGHER IN SPOTS BUT IT IS
POSSIBLE THAT THE BEST CHANCE FOR CONVECTION COULD END UP BEING
ACROSS THE SOUTHERN/EASTERN CWA GIVEN THE LIKELY TRACK OF THE DRY
SLOT AND ARRIVAL OF INSTABILITY. SO CONFIDENCE IN SPECIFIC AMOUNTS
AND WHERE THEY OCCUR IS STILL LIMITED. HOWEVER...EVEN SOMEWHAT
LOWER AMOUNTS THAN THOSE ABOVE ARE STILL A CONCERN GIVEN THE
AMOUNT OF WATER IN THE CURRENT SNOW PACK. REFERENCE HYDROLOGY
SECTION BELOW AND ESFLOT PRODUCT FOR MORE DETAILS.
SUNDAY NIGHT AND MONDAY...TIMING DIFFERENCES BECOME MORE CRITICAL AS
THE SYSTEM DEPARTS SUNDAY NIGHT AND MONDAY. IN TERMS OF FRONTAL
TIMING...THERE IS GOOD AGREEMENT ON HAVING THE COLD FRONT SWEEP
ACROSS THE AREA SUNDAY AFTERNOON WHICH ALLOWS COLDER AIR TO
ARRIVE...BUT THE SPEED WITH WHICH IT ARRIVES IS NOT QUITE CLEAR. THE
ECMWF/GEM REMAIN SLOWER WITH THE PASSAGE OF THE UPPER TROUGH AXIS
DELAYING THE ARRIVAL OF COLDEST AIR...AS WELL AS THE ATTENDANT
DEFORMATION FORCING HOLDING IT OFF UNTIL CLOSER TO MONDAY MORNING.
THE NAM AND GFS ARE FASTER WITH THE UPPER TROUGH AND ARRIVAL OF COLD
AIR. THIS WILL PLAY HAVOC WITH PRECIP TIMING AND TYPE BEHIND THE
FRONT INTO MONDAY MORNING. WILL NEED TO MONITOR THIS PERIOD AS THERE
IS AT LEAST SOME SUPPORT FOR MEASURABLE PRECIP MONDAY.
MDB
LONG TERM...MONDAY NIGHT THROUGH FRIDAY...
THE EXTENDED PERIOD WILL FEATURE A FAIRLY PROGRESSIVE NORTHWEST TO
PERHAPS ZONAL FLOW WITH SEVERAL WEAK SYSTEMS TO AFFECT PART OF THE
REGION/GREAT LAKES. TIMING ANY OF THESE FEATURES IS SOMEWHAT
DIFFICULT AS THEIR STRENGTH/LOCATION CONTINUES TO FLUCTUATE FROM
RUN TO RUN AS WELL AS FROM MODEL TO MODEL. WHILE THERE WILL BE A
FEW CHANCES FOR PRECIP...WILL CONTINUE WITH MAINLY A DRY FORECAST
DUE TO LOW CONFIDENCE THOUGH HAVE INCLUDED A SLIGHT CHANCE OF
SHOWERS ON FRIDAY AS THERE HAS BEEN SOME CONTINUITY DURING THIS TIME
PERIOD. SHOULD PRECIP CHANCES/TRENDS INCREASE...PRECIP TYPE WILL
BECOME A CONCERN DEPENDING ON TIME OF DAY.
TEMPERATURES ARE EQUALLY CHALLENGING...DEPENDING ON THE TIMING OF
THESE FEATURES AND THE EXTENT OF COLD AIR THEY BRING WITH THEM.
ECMWF HAD BEEN FAIRLY CONSISTENT WITH A PUSH OF COLDER AIR THURSDAY
INTO FRIDAY WHICH IS NOW GONE WHILE THE GFS IS NOW MUCH COLDER. HAVE
TRENDED MIDDLE OF THE ROAD WITH TEMPS AND GIVEN MID MARCH SUNSHINE...
LACK OF ANY SIGNIFICANT COLD AIR PUSH WOULD SUPPORT TEMPS NEAR
SEASONAL NORMALS.
CMS
&&
.HYDROLOGY...
234 PM CST
SOME AREAS OF THE FORECAST AREA MAY SEE 0.75-1.00 INCHES
OF RAINFALL FROM SATURDAY THROUGH SUNDAY...WITH THE BULK EXPECTED
SATURDAY EVENING/NIGHT. AT THIS POINT...THESE RAINFALL AMOUNTS ARE
EXPECTED GENERALLY WEST OF A LINE FROM CHICAGO TO PONTIAC WITH
LESSER AMOUNTS SOUTHEAST BUT THERE IS SOME OPPORTUNITY FOR THE
LOCATION TO NEED ADJUSTMENT. IN ADDITION...SOME CONVECTIVE
RAINFALL IS POSSIBLE WHICH COULD RESULT IN LOCALLY HIGHER AMOUNTS.
OBSERVED SNOW CORE WATER EQUIVALENTS RANGE FROM AROUND AN INCH TO
AROUND 2.5 INCHES WHERE THE DEEPEST SNOW EXISTS...MAINLY NORTH OF
INTERSTATE 80. FROST DEPTH REMAINS IN THE 6 TO 10 INCH RANGE. THE
EXPECTATION IS THAT THE SNOW WILL MELT AND RUNOFF WILL BE REALIZED
BEFORE THE FROST MELTS SIGNIFICANTLY DUE TO THE INSULATING
EFFECTS OF THE SNOW PACK. SNOW MELT WILL COMMENCE BEFORE THE BULK
OF THE RAINFALL WHICH COULD ALLOW SOME OF THE RUNOFF INTO AREA
RIVERS AND STREAMS TO MAKE PROGRESS DOWNSTREAM BUT THIS WOULD
LIKELY BE MINIMAL. MOST MELT WILL LIKELY OCCUR WITH THE RAINFALL
SO RIVER RISES WILL OCCUR AND SOME RIVERS COULD EXCEED FLOOD STAGE
LATER SUNDAY/MONDAY. AREAL OVERLAND FLOODING IS A
POSSIBILITY...MAINLY IN LOW LYING AND POORLY DRAINED AREAS.
REFERENCE ESFLOT FOR ADDITIONAL INFORMATION.
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* CHANCE OF SOME LIGHT RAIN THIS AFTERNOON.
* RAIN AND FOG TIMING TONIGHT.
* MVFR CIGS AND VISIBILITY LIKELY AFTER 06 UTC SATURDAY NIGHT.
* IFR CIGS AND VISIBILITY POSSIBLE BY DAYBREAK ON SUNDAY MORNING.
* LLWS POSSIBLE SATURDAY NIGHT.
KJB
//DISCUSSION...UPDATED 06Z...
THE MAIN CONCERNS DURING THE PERIOD WILL BE WITH OUR NEXT STORM
SYSTEM...WHICH IS CURRENTLY TAKING SHAPE ACROSS THE FRONT RANGE OF
THE COLORADO ROCKIES. THIS SYSTEM IS ALREADY TRANSPORTING WARM AND
MOIST AIR NORTHWARD ACROSS THE PLAINS AND INTO THE MID MISSOURI
VALLEY WITH SCATTERED SHOWERS AND EVEN SOME THUNDERSTORMS ONGOING
ACROSS THIS REGION.
IT APPEARS SOME OF THESE SHOWERS MAY EFFECT KRFD AROUND
DAYBREAK...AND WITH TEMPERATURES POSSIBLY NEAR FREEZING...I OPTED TO
LEAVE THE -FZRA IN THE NEW TAF FROM 12-14 UTC THIS MORNING.
HOWEVER...I HAVE LOW CONFIDENCE IN THE FREEZING THREAT AS
TEMPERATURES MAY ACTUALLY JUMP ABOVE FREEZING PRIOR TO THE ONSET OF
THE PRECIPITATION. IN ADDITION...I AM NOT SURE HOW MUCH IF ANY PRECIP
WILL ACTUALLY FALL THIS MORNING. THERE IS STILL SOME DRY AIR IN THE
LOW LEVELS TO OVERCOME...AND IT APPEARS THAT CIGS WILL STILL BE AT
OR ABOVE 9000 FEET THROUGH 15 UTC. WITH THIS IN MIND...WE MAY NOT
SEE MORE THAN A FEW SPRINKLES DURING THE EARLY MORNING HOURS AT
KRFD.
IT APPEARS MOST OF THE DAY PRIOR TO 20 UTC WILL BE DRY. AFTER 20 UTC
WE COULD GET ANOTHER BATCH OF LIGHT RAIN ACROSS THE TAF SITES. THIS
ALSO APPEARS AS THOUGH IT WILL BE RATHER LIGHT...AND I HAVE OPTED TO
KEEP THE PROB 30 GROUP GOING FOR THIS ACTIVITY. I
DID...HOWEVER...TRIM THE END TIME OF THE PROB 30 GROUP TO 01 UTC AS
IT APPEARS THERE WILL BE QUITE A BIT OF DRY TIME THIS EVENING AHEAD
OF THE MAIN BATCH OF RAIN.
RAIN SHOULD ONSET AROUND OR SHORTLY AFTER 03 UTC THIS EVENING AT
KRFD AND AFTER 06 UTC AT THE EASTERN TERMINALS AS THE MAIN STORM
SYSTEM APPROACHES THE AREA. IT APPEARS THE RAIN WILL BE MODERATE AT
TIMES WITH CIGS GRADUALLY LOWERING INTO THE IFR CATEGORY BY EARLY
SUNDAY. VISIBILITIES WILL ALSO BE DEGRADING INTO AT LEAST THE
MVFR RANGE IN RAIN AND FOG. LOW CLOUDS AND FOG LOOK TO CONTINUE INTO
THE DAY ON SUNDAY AS THE SURFACE LOW MOVES OVERHEAD AND SURFACE
DEW POINTS PEAK IN THE LOWER TO MIDDLE 40S.
THERE IS ALSO A CHANCE OF LLWS SATURDAY NIGHT AS IT APPEARS THE A
SOUTHWESTERLY 50-55 LOW LEVEL JET WILL DEVELOP AROUND 2,000 FT AGL.
SURFACE WINDS DURING THIS TIME ARE EXPECTED TO BE AROUND 10 KT OUT
OF THE SOUTH. I HAVE OPTED NOT TO ADD THIS TO THE NEW TAF...BUT IT
MAY NEED TO BE ADDED AT A LATER TIME IF THESE CONDITIONS APPEAR TO BE
SETTING UP.
KJB
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* LOW CONFIDENCE ON ANY LIGHT RAIN AFFECTING THE TERMINALS THIS
AFTERNOON.
* MEDIUM TO HIGH CONFIDENCE IN RAIN AND FOG REDUCING VISIBILITIES
UNDER 4 MILES LATER SUNDAY NIGHT AFTER 06 UTC.
* MEDIUM CONFIDENCE IN IFR CIGS TOWARDS DAYBREAK SUNDAY.
* LOW TO MEDIUM CONFIDENCE IN LLWS SATURDAY NIGHT.
KJB
//OUTLOOK FOR ORD/MDW FOR 12Z SUNDAY-12Z FRIDAY...UPDATED 00Z...
SUNDAY...RAIN AND FOG WITH LIKELY IFR. A CHANCE FOR A MIX WITH
SNOW DURING THE NIGHT.
MONDAY...SLIGHT CHANCE OF RAIN AND SNOW WITH MVFR.
TUESDAY-THURSDAY...VFR.
MTF
&&
.MARINE...
125 PM CST
THE HIGH PRESSURE THAT BROUGHT LIGHT AND VARIABLE WINDS TO LAKE
MICHIGAN HAS MOVED EAST OF THE LAKE AND WINDS HAVE BECOME
SOUTHERLY. AS DEEPENING LOW PRESSURE MOVES OUT OF THE ROCKIES AND
INTO THE SOUTHERN PLAINS...WHILE THE HIGH MOVES SLOWLY TO THE
EAST...THE GENERALLY SOUTHERLY WINDS WILL STRENGTHEN THROUGH THE
WEEKEND. BY SATURDAY EVENING...THE HIGH WILL MOVE TO THE EASTERN
SEABOARD WHILE THE LOW PRESSURE MOVER THE SOUTH HIGH PLAINS DEEPENS
AND A TROUGH OF LOW PRESSURE ELONGATES TO ANOTHER...WEAKER LOW JUST
NORTH OF MINNESOTA. SOUTHERLY WINDS WILL INCREASE TO AROUND 30 KT
AS THE TROUGH OF LOW PRESSURE AND AN ASSOCIATED COLD FRONT APPROACH
THE LAKE. THE COLD FRONT IS EXPECTED TO SWEEP ACROSS THE LAKE
SUNDAY...WITH WINDS QUICKLY VEERING TO NORTHERLY. WITH HIGH
PRESSURE QUICKLY BUILDING IN ACROSS THE LAKE BEHIND THE COLD
FRONT...THE NORTHERLY WINDS WILL ONLY BRIEFLY INCREASE TO AROUND 25
KT SUNDAY NIGHT BEFORE DROPPING OFF TO 5 TO 10 KT BY MONDAY NIGHT.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1151 PM CST FRI MAR 8 2013
.DISCUSSION...
ISSUED 855 PM CST FRI MAR 8 2013
UPDATED THE FORECAST TO INCREASE CLOUD COVER TONIGHT AND ELEVATE
LOW TEMPERATURES UP A DEGREE OR TWO. LOWS RANGE FROM NEAR 30F OVER
EAST CENTRAL IL TO THE UPPER 30S FROM SPRINGFIELD SW. CONTINUE A
CHANCE OF LIGHT RAIN SHOWERS OVERNIGHT OVER THE IL RIVER VALLEY...
WITH BEST CHANCES NW OF THE IL RIVER LATE TONIGHT.
1031 MB HIGH PRESSURE OVER SE LOWER MI INTO OHIO AND EASTERN KY
THAT PROVIDE A NICE DAY TO CENTRAL/SE IL WITH AMPLE SUNSHINE AND
MILDER 40S WILL DRIFT INTO THE EASTERN GREAT LAKES SAT MORNING.
1001 MB LOW PRESSURE OVER SE CO WILL DEEPEN TO 997 MB NEAR THE SE
CO/SW KS BORDER BY MIDDAY SAT WITH A FRONTAL BOUNDARY EXTENDING NE
INTO FAR NW IA AND INTO MN. A WARM FRONT OVER SW MO INTO SOUTH
CENTRAL NE WILL LIFT NE TOWARD SW IL SAT MORNING. STRONG WAA
ADVECTION AND ISENTROPIC LIFT TO DEVELOP AND SPREAD LIGHT RAIN
SHOWERS FROM CENTRAL AND WESTERN MO/IA INTO THE IL RIVER VALLEY
OVERNIGHT INTO SAT MORNING MAINLY AFTER 09Z/3 AM. HRRR APPEARS TO
WET WITH SHOWERS OVER MOST OF CWA OVERNIGHT. SINCE SOUNDINGS ARE
QUITE DRY ESPECIALLY FROM I-55 EAST...THIS SHOULD KEEP AREAS FROM
I-55 EAST DRY TONIGHT. TEMPS CURRENTLY IN THE MID TO UPPER 30S
FROM MACOMB TO LINCOLN TO MATTOON NE AND 40-45F SW WILL SLIP ONLY
A FEW MORE DEGREES DUE TO INCREASING/THICKENING MID/HIGH CLOUDS AND
ESE WINDS OF 5-15 MPH.
07
&&
.AVIATION...
ISSUED 1150 PM CST FRI MAR 8 2013
VFR CONDITIONS GENERALLY EXPECTED TO PREVAIL ACROSS THE CENTRAL IL
TERMINAL AIRPORTS NEXT 24 HOURS THROUGH 06Z/MIDNIGHT SAT NIGHT.
EXPECT BROKEN TO OVERCAST MID LEVEL CLOUDS TO LOWER FROM 10-15K FT
TO 5-10K FT DURING OVERNIGHT INTO SAT MORNING...THEN LIFT BACK UP
TO AROUND 10K FT SAT AFTERNOON INTO MID EVENING SAT. STRONG WAA AND
ISENTROPIC LIFT TO GENERATE A LIGHT BAND OF SHOWERS OVER CENTRAL
IL OVERNIGHT (SPI RECENTLY REPORTED SPRINKLES) WITH VSBYS STAYING
ABOVE 5 MILES. MORE WIDESPREAD SHOWERS COULD BRUSH THE IL RIVER
VALLEY NEAR PIA SAT MORNING AND POSSIBLY LINGER INTO EARLY SAT
AFTERNOON WITH CEILINGS DOWN TO 3-5K FT AND VSBYS DOWN TO 5 MILES.
SE WINDS 10-15 KTS OVERNIGHT TO INCREASE TO AROUND 15 KTS WITH
GUSTS 20-25 KTS BY 15Z/SAT AND VEER SSE SAT EVENING. 1000 MB LOW
PRESSURE OVER SE CO TO MOVE INTO SE KS BY 06Z/MID SAT NIGHT WITH A
FRONTAL BOUNDARY INTO EASTERN IA. THIS WILL BRING A WIDESPREAD
BAND OF MODERATE SHOWERS EAST TOWARD THE IL RIVER VALLEY AFTER
04Z/10 PM SAT AND LIKELY TO AFFECT PIA AND NEAR I-55 AT BMI AND SPI
NEAR OR JUST AFTER 06Z/MID SAT NIGHT.
07
&&
.PREV DISCUSSION...
ISSUED 300 PM CST FRI MAR 8 2013
OUR SURFACE PATTERN IS CURRENTLY DOMINATED BY HIGH PRESSURE
EXTENDING FROM THE WESTERN GREAT LAKES ON SOUTH TO
MISSISSIPPI...WHILE LOW PRESSURE IN THE SOUTHWEST STATES BEGINS TO
MOVE ONSHORE AND DEVELOP UNDER A STRENGTHENING JET STREAM. THAT
SYSTEM WILL BECOME OUR MAIN WEATHER ISSUE FOR THE NEXT 3 DAYS OR
SO. OUTSIDE OF A BRIEF COOL DOWN ON MONDAY INTO
TUESDAY...TEMPERATURES OVER THE NEXT WEEK WILL BE AT OR ABOVE
NORMAL.
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT.
MID AND HIGH CLOUDS WILL ADVANCE INTO ILLINOIS TONIGHT AS MID
LEVEL WARM ADVECTION AND MOISTURE FLOWS BEGIN TO SATURATE THE
LOWER TROPOSPHERE. FORECAST SOUNDINGS ARE INDICATING MOST AREAS
WILL REMAIN DRY OVERNIGHT...ALTHOUGH WE CANT RULE OUT SOME LIGHT
RAIN SHOWERS FOR OUR FAR WESTERN COUNTIES FROM SCHUYLER TO KNOX
LATE TONIGHT. THE GFS IS THE ONLY MODEL TO BRING MUCH IN THE WAY
OF MEASURABLE RAIN BEFORE 12Z TO OUR WESTERN COUNTIES...SO WE
OPTED TO TREND VERY LOW ON THE POPS TONIGHT.
ON SATURDAY...THE PRIMARY FORCING FOR PRECIP WILL REMAIN FOCUSED
NORTHWEST OF I-55...WHILE AREAS SOUTHEAST OF I-55 REMAIN MAINLY
DRY. WE KEPT LIKELY POPS TOWARD FULTON AND KNOX COUNTIES...WITH
CHANCE POPS DOWN TO I-55. SOUTHEAST WINDS WILL BEGIN TO RESPOND TO
THE PRESSURE FALLS BY SATURDAY AFTERNOON...WITH WINDS IN THE 20-30
MPH RANGE AT TIMES. THE GUSTY WINDS WILL CONTINUE TO AID THE
MOISTURE TRANSPORT IN THE BOUNDARY LAYER SATURDAY NIGHT. WE
KEPT CATEGORICAL POPS SAT EVENING AND EXPANDED THEM NEARLY
EVERYWHERE AFTER MIDNIGHT.
THE BULK OF OUR RAINFALL AMOUNTS LOOK TO BE FOCUSED FROM MIDNIGHT
SATURDAY NIGHT THROUGH NOON ON SUNDAY...WITH ELEVATED THUNDERSTORMS
EVEN POSSIBLE AT TIMES LATE SAT NIGHT AND SUNDAY MORNING AS THE
COLD FRONT MOVES ACROSS THE AREA. WE KEPT THE MENTION OF THUNDER
MAINLY CONFINED WEST OF SPI SAT NIGHT AND SOUTH OF LINCOLN ON
SUNDAY MORNING. STRONG SOUTH WINDS WILL ACCOMPANY THE RAIN SHOWERS
AND STORMS AS THEY PUSH ACROSS THE AREA. WIND GUSTS OVER 30MPH
WILL BE POSSIBLE.
BY SUNDAY AFTERNOON THE BEST INSTABILITY WILL HAVE SHIFTED EAST
INTO INDIANA AS COLDER AIR BEGINS TO INVADE CENTRAL IL ON
NORTHWEST WINDS. DOWNWARD ISENTROPIC MOTIONS AND A DRY PUSH ALOFT
WILL HELP TO DIMINISH PRECIP SUNDAY NIGHT FROM NW TO SE. WE KEPT
CHANCE POPS IN THE SOUTHEAST HALF...WITH THE POTENTIAL FOR SOME
LIGHT SNOW NW OF I-70 AFTER MIDNIGHT. LITTLE IN THE WAY OF SNOW
ACCUMULATION IS EXPECTED...AS THE WET AND WARM GROUND MELTS MOST
OF ANY SNOWFALL.
LONG TERM...MONDAY THROUGH FRIDAY.
LINGERING LIGHT SNOW OR RAIN ON MONDAY MORNING SHOULD TAPER TO
SPRINKLES BY AFTERNOON. WE KEPT SLIGHT CHANCE POPS IN THE
SOUTHEAST...BUT MOST PRECIP SHOULD BE TRACE AMOUNTS BY THAT TIME.
THE COLDEST TEMPS OF THE NEXT WEEK SHOULD BE ON MONDAY AND MONDAY
NIGHT...WITH HIGHS ONLY AROUND 40 AND LOWS IN THE MID 20S. TEMPS
WILL BEGIN A WARMING TREND ON TUESDAY WHICH WILL CONTINUE THROUGH
THURSDAY WHEN HIGHS RETURN TO THE 50S. A COOL DOWN IS PROJECTED
FOR THURSDAY NIGHT INTO FRIDAY AS THE NEXT COLD FRONT MOVES
ACROSS THE AREA EITHER EARLY THURSDAY MORNING /GFS/ OR LATE
THURSDAY /ECMWF/. STILL THE COLDER AIR WILL NOT PLUNGE VERY FAR
SOUTH INTO OUR COUNTIES...SO THE COOL DOWN WILL BE TEMPORARY.
PRECIP CHANCES HAVE BEEN KEPT IN THE SLIGHT CHANCE CATEGORY...AND
ONLY ON FRIDAY FOR NOW.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
542 PM MDT SUN MAR 10 2013
.UPDATE...
ISSUED AT 540 PM MDT SUN MAR 10 2013
WINDS HAD DECREASED TO BELOW ADVISORY CRITERIA SO WIND ADVISORY
HAS BEEN CANCELLED.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 143 PM MDT SUN MAR 10 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW LONG WAVE TROUGH
EXTENDING FROM GREAT LAKES ACROSS THE THE CENTRAL PLAINS WITH BASE
OF TROUGH OVER BAJA PENINSULA. STACKED H7/H5 CLOSED LOW CENTER IS
CURRENTLY OVER NE KANSAS WITH SHORTWAVE RIDGE BUILDING ACROSS
WESTERN US INTO THE NORTHERN PLAINS ON THE BACK SIDE OF THIS SYSTEM.
BETWEEN THE RIDGE AND CLOSED LOW A STRONG AXIS OF SUBSIDENCE IN IN
PLACE ACROSS OUR CWA. TIGHT PRESSURE GRADIENT IS CURRENTLY IN PLACE
ACROSS THE EASTERN HALF OF THE CWA WITH HIGH PRESSURE BUILDING OVER
EASTERN COLORADO AND STRONG SURFACE LOW PRESSURE CENTERED OVER
MISSOURI.
GRADIENT WILL CONTINUE TO WEAKEN AS LARGE SCALE SYSTEM PULLS EAST
THIS AFTERNOON AND HIGH PRESSURE CONTINUES TO BUILD OVER THE CWA. WE
ARE ALREADY SEEING WINDS DECREASE BELOW ADVISORY CRITERIA OVER THE
NW HALF OF THE CWA. WINDS CONTINUE TO HOVER RIGHT AT OR ABOVE
ADVISORY CRITERIA WITH BETTER THAN ANTICIPATED AFTERNOON MIXING
ACROSS THE SE HALF OF THE AREA. I DECIDED TO EXTEND ADVISORY
00Z...THOUGH WE MIGHT BE ABLE TO EXPIRE THE ADVISORY EARLY
ESPECIALLY FOR THE NW COUNTIES.
WINDS WILL DECREASE RAPIDLY AROUND SUNSET WITH LIGHT W/NW WINDS
EXPECTED OVERNIGHT TONIGHT. WITH SHORTWAVE RIDGE BUILDING EAST FLOW
ALOFT WITH SHIFT TO A NW WITH LEE TROUGH BEGINNING TO REDEVELOP OVER
EASTERN COLORADO BY 12Z TONIGHT. EARLY THIS AFTERNOON EASTERN
LOCATIONS COULD STILL SEE A FEW FLURRIES AS ENERGY ROTATES ON THE
BACK SIDE OF UPPER LOW...HOWEVER BEYOND THIS THE FORECAST SHOULD
REMAIN DRY THROUGH THE DAYTIME PERIOD MONDAY.
THERE WILL BE A MODERATION OF THE AIR MASS OVER OUR CWA FROM THE
WEST TO THE EAST TONIGHT WHICH WILL CONTINUE THROUGH THE DAY
MONDAY. IT IS DIFFICULT TO TELL WHAT IMPACT RECENT SNOW PACK WILL
HAVE ON TEMPS TONIGHT AND MONDAY WITH PAST EVENTS WARMING MUCH
FASTER THAN ORIGINALLY INDICATED. FOR NOW I THINK OUR LOWS SHOULD
COOL TO LOW TO MID TEENS FOR MOST LOCATIONS DESPITE WARMING
AIRMASS. H85 TEMPS ON MON WOULD SUPPORT HIGHS IN THE MID 50S TO
AROUND 60F UNDER IDEAL MIXING. TO ACCOUNT FOR SNOW I KEPT HIGH
FORECAST MON ABOUT 5-10F COOLER RANGING FROM UPPER 40S IN THE
NORTH TO MID 50S IN THE SOUTH WHERE LESS SNOW FELL.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 143 PM MDT SUN MAR 10 2013
LONG TERM FORECAST CONCERNS ARE THE POTENTIAL FOR FLURRIES MONDAY
NIGHT AND THE POSSIBILITY OF PRECIPITATION DURING NEXT
WEEKEND.
NORTHWEST FLOW ALOFT OVER THE FORECAST AREA AS THE RIDGE AMPLIFIES
OVER THE WESTERN UNITED STATES WILL CARRY A SHORT WAVE TROUGH
THROUGH THE CENTRAL HIGH PLAINS REGION OVERNIGHT MONDAY NIGHT.
THERE MAY BE A FEW FLURRIES ASSOCIATED WITH THIS WAVE AS MID AND
LOWER LEVEL MOISTURE INCREASES. WINDS MAY ALSO BE GUSTY OVERNIGHT
AND INTO THE DAY ON TUESDAY AS SUBSIDENCE BEHIND THIS WEAK WAVE
HELPS MIX STRONGER WINDS TO THE SURFACE.
DRY CONDITIONS WILL PERSIST THROUGH THE REMAINDER OF THE WORK WEEK
AS THE BROAD RIDGE OVER THE WESTERN UNITED STATES MOVES EASTWARD
FROM THE INTERMOUNTAIN REGION TO THE ROCKIES AND HIGH PLAINS. THE
RIDGE WILL BEGIN TO FLATTEN THURSDAY NIGHT AND FRIDAY AS A SERIES
OF WEAKER SHORT WAVE TROUGHS BEGINS TO MOVE INTO THE WEST COAST
AND ACROSS THE TOP OF THE RIDGE. MUCH WARMER THAN NORMAL
TEMPERATURES ARE EXPECTED ACROSS THE FORECAST AREA THURSDAY AND
FRIDAY.
THE FLOW FLATTENS ACROSS THE UNITED STATES TOWARDS THE END OF THE
WEEK AND INTO THE WEEKEND FOR A MORE PROGRESSIVE PATTERN. BETWEEN
FRIDAY NIGHT AND SUNDAY THE GFS AND ECMWF BEGIN TO DIVERGE IN
THERE INDIVIDUAL HANDLING OF SUBSEQUENT SHORT WAVES AND THE LARGER
SCALE UPPER TROUGH MOVING INTO THE WESTERN UNITED STATES.
DEPENDING UPON WHICH SOLUTION PANS OUT...THE CENTRAL HIGH PLAINS
REGION COULD SEE COOLER TEMPERATURES...ALTHOUGH STILL WARMER THAN
AVERAGE FOR THIS TIME OF YEAR...ALONG WITH SOME LIGHT SHOWERS
MOVING ACROSS THE AREA ON SATURDAY...OR COOLER TEMPERATURES AND A
FEW SPRINKLES ACROSS PORTIONS OF THE AREA ON SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 540 PM MDT SUN MAR 10 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
147 PM MST SAT MAR 9 2013
.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 145 PM MST SAT MAR 9 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW LARGE SCALE TROUGH
EXTENDING FROM CENTRAL CANADA AND ACROSS THE INTERMOUNTAIN
WEST...WITH A CLOSED CENTER OVER NORTHERN NEW MEXICO. H7 TROUGH AXIS
ALONG KS/CO BORDER. SATELLITE IMAGERY AND REGIONAL RADAR SHOWS
DEFORMATION BAND JUST WEST OF H7 TROUGH AXIS ACROSS EASTERN EASTERN
COLORADO EXTENDING NORTH THROUGH THE NEBRASKA PANHANDLE AND INTO
SOUTH DAKOTA. DRY SLOT DEVELOPED AHEAD OF THE TROUGH EARLY THIS
MORNING AND IS CURRENTLY IN PLACE OVER ALL BUT THE FAR WESTERN
EXTENT OF CWA.
AXIS OF MODEST INSTABILITY HAS DEVELOPED JUST EAST OF OUR CWA IN
RESPONSE TO VERY MOIST BL AND STRONG WAA AHEAD OF SURFACE LOW.
THUNDERSTORMS HAVE DEVELOPED ACROSS NORTH CENTRAL KANSAS AND CENTRAL
NEBRASKA. SURFACE TD HAVE ALREADY BEEN DECREASING AT NORTON AND HILL
CITY...SO THE THREAT FOR THUNDERSTORMS MAY BE DECREASING FOR OUR
AREA. WE COULD STILL SEE A WINDOW FOR THUNDERSTORMS TO DEVELOP IN
OUR EASTERN CWA THIS AFTERNOON BEFORE THE COLD FRONT PUSHES
EAST...SO I KEPT A SLIGHT CHANCE OF THUNDERSTORMS GOING THROUGH 00Z
FOR EASTERN LOCATIONS.
THERE ARE DIFFERENCES REGARDING THE EVOLUTION OF SNOW BAND TONIGHT
THOUGH MODEL CONSENSUS STILL SHOWS THIS BAND MOVING EAST AND
PRODUCING HEAVY SNOW ACCUMULATIONS AROUND 7 INCHES ACROSS OUR
NORTHWEST...AND LESSER AMOUNTS SOUTH AND EAST. THERE SHOULD BE A
QUICK RAIN/SNOW CHANGE OVER IN THE WEST...WITH CHANGEOVER THIS
EVENING IN THE EAST WHERE WARMER TEMPERATURES ARE STILL IN PLACE.
UPSTREAM OBS ALREADY SHOW LIGHT SNOW IN YUMA COUNTY...IN LINE WITH
CURRENT FORECAST TIMING. THE DEFORMATION BAND SHOULD WEAKEN AFTER
06Z AS LARGE SCALE FORCING BEGINS TO PULL EAST...AND DRY AIR ACROSS
THE NORTHERN ROCKIES PUSHES SOUTH AND EAST. IT IS WORTH NOTING THAT
THE LATEST GFS AND ECMWF ACTUALLY INDICATE THAT THIS SNOW BAND WILL
HOLD TOGETHER IF NOT INTENSIFY AFTER 06Z WITH HIGHER AMOUNTS BY AS
MUCH AS 2-3 INCHES MORE THAN CURRENT FORECAST. WITH RUC/NAM/GFS ALL
SHOWING INSTABILITY WITHIN 700-500MB LAYER WITH THIS BAND...THERE
MAY BE A CONNECTIVE COMPONENT THAT COULD SUPPORT LOCALLY HIGHER
AMOUNTS IN LINE WITH THESE HIGHER TOTALS...HOWEVER IT IS HARD TO
GAUGE WHERE THIS WILL SET UP AND HOW WIDESPREAD IT WILL BE. I ALSO
THINK THE WINDOW FOR CONVECTIVE BANDING WILL BE DURING THE EVENING
RATHER THAN AFTER 06Z...SINCE MODELS ARE GENERALLY INDICATING A
DECREASE IN INSTABILITY AS DRY/STABLE AIR MOVES IN FROM THE NW
BEHIND THIS BAND. WARM GROUND TEMPERATURES COULD LEAD TO ADDITIONAL
MELTING WHICH COULD EAT INTO OUR SNOW AMOUNTS EARLY ON...HOWEVER AS
SNOWFALL INTENSIFIES AND TEMPERATURES BEGIN TO DROP WE SHOULD START
TO OVERCOME THIS.
MODELS ARE STILL SHOWING STRONG H85 JET DEVELOPING BEHIND FRONT LATE
THIS AFTERNOON AND EVENING. NAM WOULD INDICATE A SMALLER WINDOW FOR
THE STRONGEST WINDS UP NORTH...HOWEVER IT STILL SHOWS POTENTIAL FOR
GUSTS AROUND 35MPH THROUGH THE NIGHT UP NORTH...AND GUSTS 40-50MPH
ACROSS THE SOUTH THROUGH MOST OF THE NIGHT. THIS SHOULD SUPPORT
WIDESPREAD BLOWING SNOW WITH WHITE OUT CONDITIONS ACROSS THE AREA.
I DECIDED AGAINST MAKING ANY WHOLESALE CHANGES TO FORECAST OR
BLIZZARD WARNING TONIGHT WITH ONLY ADJUSTMENTS TO DETAILS AND
RAIN/SNOW TIMING BASED ON CURRENT TRENDS. WE MAY NEED TO MAKE
FURTHER ADJUSTMENTS AS THIS BAND STARTS MOVING EAST AND WE GET A
BETTER HANDLE ON HOW QUICKLY IT WEAKENS LATE TONIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 145 PM MST SAT MAR 9 2013
THE STORM THAT IS AFFECTING OUR FORECAST AREA THIS WEEKEND WILL
BE HEADING OUT OF THE PLAINS REGION AND WILL BE MOVING TOWARDS THE
GREAT LAKES AND MISSISSIPPI VALLEY REGIONS ON SUNDAY NIGHT AND
MONDAY. A COUPLE OF WEAK SHORT WAVE TROUGHS WILL MOVE ACROSS THE
CENTRAL HIGH PLAINS REGION IN THE UPPER NORTHWEST FLOW MONDAY
MORNING AND DURING THE DAY ON WEDNESDAY...OTHERWISE THE RIDGE THAT
MOVES INTO THE WESTERN UNITED STATES DURING THE FIRST PART OF NEXT
WEEK BECOMES A BROAD RIDGE OVER THE WESTERN UNITED
STATES...EXTENDING FROM THE INTERMOUNTAIN REGION TO THE PLAINS
STATES BY THE END OF THE WEEK.
THE RIDGE APPEARS TO WEAKEN SOMEWHAT BY NEXT WEEKEND AS ANOTHER
TROUGH APPROACHES THE WEST COAST...BUT THERE IS CURRENTLY A LARGE
AMOUNT OF DISAGREEMENT IN THE MODELS OVER THE WEST COAST DURING
THAT TIME PERIOD. BY NEXT SATURDAY...THE CENTRAL HIGH PLAINS
REGION SEEMS TO STILL BE UNDER A WEAK RIDGE WITH A TRANSITION IN
THE PATTERN UNDERWAY OVER THE WESTERN UNITED STATES.
WITH UNIDIRECTIONAL NORTH TO NORTHWEST FLOW THROUGH THE ATMOSPHERE
SUNDAY NIGHT AND MONDAY...BREEZY CONDITIONS COULD PERSIST THROUGH
THAT TIME ACROSS THE FORECAST AREA. OTHER THAN SOME WIND EARLY IN
THE LONG TERM PERIOD...THE CONDITIONS DURING THE LONG TERM PORTION OF
THE FORECAST APPEAR TO BE BENIGN WITH NO PRECIPITATION EXPECTED
AND GOOD AGREEMENT BETWEEN MODEL SOLUTIONS. TEMPERATURES WILL
CONTINUE TO RISE EACH DAY WITH HIGH TEMPERATURES INCREASING FROM
THE UPPER 40S AND LOWER 50S ON MONDAY TO THE UPPER 60S AND LOWER
70S BY FRIDAY. LOW TEMPERATURES WILL INCREASE FROM THE UPPER TEENS
ON SUNDAY NIGHT TO THE UPPER 30S BY FRIDAY NIGHT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1035 AM MST SAT MAR 9 2013
EARLY IN THE TAF PERIOD IFR CIGS ASSOCIATED WITH STRATUS DECK WILL
LINGER AT BOTH KGLD/KMCK...WITH LIGHT FOG AND MVFR VIS LINGERING.
MAIN BAND OF RAIN/SNOW OVER EASTERN COLORADO IS EXPECTED TO
OVERSPREAD BOTH TERMINALS THIS AFTERNOON WITH COVERAGE INCREASING
LATE THIS AFTERNOON THROUGH THE EVENING. SHOULD SEE A GRADUAL
REDUCTION IN AVIATION CONDITIONS WITH LIFR ASSOCIATED WITH SNOW
AND BLOWING SNOW THIS EVENING THROUGH EARLY SUNDAY MORNING. BASED
ON CURRENT TIMING I EXPECT THE MAIN BAND SHOULD WEAKEN AND SHIFT TO
THE EAST WITH CONDITIONS IMPROVING AT KGLD AFTER 09Z AND THEN
AROUND 10Z AT KMCK. VFR CIG/VIS IS EXPECTED BY MID MORNING AT BOTH
TERMINALS WITH DRY/STABLE AIR MOVING IN ON BACK SIDE OF UPPER LOW.
IT IS WORTH NOTING THAT THERE COULD BE A FEW THUNDERSTORM DEVELOP
THIS AFTERNOON AHEAD OF COLD FRONT...HOWEVER THIS SHOULD BE EAST
OF BOTH TERMINALS...SO I LEFT MENTION OF OUT TAFS.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...BLIZZARD WARNING UNTIL 9 AM MDT /10 AM CDT/ SUNDAY FOR KSZ001-
013-027.
BLIZZARD WARNING FROM 5 PM MST /6 PM CST/ THIS AFTERNOON TO 9 AM
MDT /10 AM CDT/ SUNDAY FOR KSZ002>004-014>016-028-029-041-
042.
CO...BLIZZARD WARNING UNTIL 9 AM MDT SUNDAY FOR COZ090>092.
NE...BLIZZARD WARNING UNTIL 9 AM MDT /10 AM CDT/ SUNDAY FOR NEZ079-
080.
BLIZZARD WARNING FROM 6 PM CST THIS EVENING TO 10 AM CDT SUNDAY
FOR NEZ081.
&&
$$
SHORT TERM...DR
FS LONG TERM...LOCKHART
AVIATION...DR
AREA FORECAST DISCUSSION
NWS WICHITA KS
1150 PM CST FRI MAR 8 2013
.AVIATION...06Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
EXPECT DETERIORATING AVIATION CONDITIONS OVERNIGHT TO IFR CONDITIONS
BETWEEN 06-12Z/SAT AT MOST LOCATIONS AS WIDESPREAD SHOWERS MOVE INTO
THE AREA. THIS INITIAL ROUND OF SHOWERS AND EMBEDDED THUNDERSTORMS
WILL MOVE INTO AREAS WEST OF INTERSTATE 135 IN THE NEXT COUPLE OF
HOURS. WILL SEE ANOTHER ROUND OF SHOWERS AND EMBEDDED THUNDER MOVE
IN AROUND 12Z/SAT...WITH WIDESPREAD SHOWERS REMAINING ACROSS THE
AREA THROUGH 18Z/SAT.
THE DRY LINE ASSOCIATED WITH THIS STORM SYSTEM WILL PUSH INTO THE
KRSL/KHUT AND KICT TAF SITES FOR SAT AFTERNOON...WHICH WILL SCOUR
OUT THE IFR CEILINGS...AS A MID LEVEL DRY SLOT MOVES ACROSS THE
AREA. THIS DRYING OUT OF THE LOW LAYERS...AND SOME POSSIBLE HEATING
DUE SOME PEAKS OF SUNSHINE MAY ALSO LEAD TO A RENEWED CHANCE OF
THUNDERSTORMS FOR THE KHUT/KICT AND KSLN TAFS...SO WILL INCLUDE A
VCTS FOR THIS CHANCE FOR NOW.
MAIN LOW PRESSURE AREA ASSOCIATED WITH THIS STORM SYSTEM WILL MOVE
ACROSS THE FORECAST AREA FOR SAT EVENING. THIS WILL KEEP THE WINDS
OUT OF THE SOUTH FOR THE EVENING HOURS...BUT A STRONG COLD FRONT
WILL BEGIN PUSH SOUTH INTO CEN KS BY AROUND 06Z/SUN...WHICH IS
BEYOND THIS TAF SET.
KETCHAM
&&
.PREV DISCUSSION... /ISSUED 905 PM CST FRI MAR 8 2013/
UPDATE...
THE SCATTERED SHOWER CHANCES HAVE BEEN SLOW TO GET GOING ACROSS MOST
OF THE FORECAST AREA AT THIS TIME. WITH MAINLY SOME WIDELY SCATTERED
SPRITZES/SPRINKLES OR DRIZZLE. LOW LEVEL ISENTROPIC LIFT CONTINUES
TO LEAD TO LOTS OF LOW-MID CLOUDS WITH THIS LOW LEVEL SATURATION
LEADING TO GRADUALLY LOWER CEILINGS. THINK THE WIDESPREAD SHOWER
CHANCES WILL WAIT UNTIL THE INITIAL IMPULSE /THAT IS LEADING TO THE
LINE OF CONVECTION IN THE TX PANHANDLE/ BEGINS TO LIFT NORTHEAST
INTO SRN KS AFTER MIDNIGHT.. THINK AS THIS IMPULSE LIFTS
NORTH...SHOWERS WILL BECOME MORE WIDESPREAD FOR AREAS WEST OF
INTERSTATE 135...WHERE BETTER MOISTURE TRANSPORT IS ALREADY IN
PLACE. SHORT TERM RUC ALSO SHOWS SOME ELEVATED MUCAPE AROUND 400-600
J/KG MOVING INTO THIS AREA AS WELL...SO THINK SOME RUMBLES OF
EMBEDDED THUNDER MAY ALSO MOVE IN AS WELL. CURRENT GRIDS/ZONES LOOK
RIGHT ON TRACK...WITH POPS A LITTLE HIGH EARLY ON...BUT THEY LOOK
FINE FOR AFTER MIDNIGHT.
KETCHAM
PREV DISCUSSION... /ISSUED 558 PM CST FRI MAR 8 2013/
AVIATION...00Z TAFS KRSL/KSLN/KHUT/KICT/KCNU
MVFR CEILINGS WILL GRADUALLY MOVE INTO MOST OF THE TAF SITES THIS
EVENING. EXPECT DETERIORATING AVIATION CONDITIONS OVERNIGHT TO IFR
CONDITIONS BETWEEN 06-12Z/SAT AT MOST LOCATIONS AS WIDESPREAD
SHOWERS DEVELOP. COULD ALSO SEE SOME EMBEDDED THUNDER AS WELL FOR
MOST TAF LOCATIONS BETWEEN 12-18Z/SAT. THE DRY LINE ASSOCIATED WITH
THIS STORM SYSTEM WILL PUSH INTO THE KRSL/KHUT AND KICT TAF SITES
LATE IN THE TAF PERIOD...WHICH WILL SCOUR OUT THE IFR CEILINGS. THIS
DRYING OUT OF THE LOW LAYERS...AND SOME POSSIBLE HEATING DUE SOME
PEAKS OF SUNSHINE MAY ALSO LEAD TO A RENEWED CHANCE OF
THUNDERSTORMS...SO WILL INCLUDE A VCTS FOR THIS CHANCE FOR THE
KHUT/KRSL/KSLN AND KICT TAF SITES.
KETCHAM
PREV DISCUSSION... /ISSUED 328 PM CST FRI MAR 8 2013/
DISCUSSION...
FORECAST HIGHLIGHTS FOCUS AROUND PRECIPITATION CHANCES
TONIGHT-SUNDAY...INCLUDING THE POTENTIAL FOR A FEW STRONG SEVERE
STORMS SATURDAY AFTERNOON-EVENING...AND SNOW SATURDAY NIGHT-SUNDAY
MORNING.
IMPRESSIVE LOOKING UPPER LOW WITH QUITE A BIT OF LIGHTNING IS
CURRENTLY SPINNING OVER THE DESERT SOUTHWEST. AS THIS STORM SYSTEM
APPROACHES THE REGION TONIGHT...ANTICIPATING WIDESPREAD SHOWERS
WITH EMBEDDED THUNDERSTORMS TO BE ON THE INCREASE...ESPECIALLY
AFTER MIDNIGHT GENERALLY OVER CENTRAL AND SOUTH-CENTRAL KS. GIVEN
WEAK INSTABILITY...CANNOT RULE OUT SMALL HAIL WITH THE STRONGEST
STORMS. THIS WIDESPREAD SHIELD OF SHOWERS/THUNDERSTORMS WILL
GRADUALLY SHIFT EAST ACROSS THE AREA DURING THE DAY SATURDAY...IN
ZONE OF STRONG LOW TO MID-LEVEL WARM/MOIST ADVECTION AHEAD OF
APPROACHING UPPER WAVE.
BY TOMORROW MID-AFTERNOON...BRUNT OF MAIN PRECIPITATION SHIELD
SHOULD BE OVER THE EASTERN 1/3 OF KS...WITH SURFACE DRYLINE HANGING
BACK WESTWARD OVER CENTRAL/SOUTH-CENTRAL KS...AND COOLING/DRYING
ALOFT OVERSPREADING THE WARM SECTOR AHEAD OF APPROACHING SHORTWAVE.
IF BREAKS IN OVERCAST CAN DEVELOP ALLOWING SOME HEATING IN WAKE OF
MAIN PRECIPITATION SHIELD...THINKING THERE COULD BE A WINDOW OF
OPPORTUNITY FROM MID-AFTERNOON THROUGH EARLY EVENING FOR SCATTERED
SHALLOW/LOW-TOPPED SURFACE BASED CONVECTION GENERALLY ALONG/WEST OF
I-135 CORRIDOR. IF ENOUGH INSTABILITY CAN MATERIALIZE FOR
STORMS...LOW-TOPPED SUPERCELLS WILL BE POSSIBLE GIVEN STRONGLY
SHEARED ENVIRONMENT...WITH THE POTENTIAL FOR SOME LARGE HAIL.
ADDITIONALLY...NAM BUFR SOUNDINGS INDICATE DECENT LOW-LEVEL CAPE
OWING TO MID-UPPER 50F DEWPOINTS AND STEEPENING LAPSE RATES...WHICH
WOULD SUPPORT THE POTENTIAL FOR AN ISOLATED TORNADO OR TWO. WILL NOT
COMPLETELY BITE ONTO THE OMINOUS NAM SOLUTION JUST YET GIVEN
AFTERNOON HEATING/INSTABILITY QUESTIONS...BUT DEFINITELY SOMETHING
FOR THE NIGHT SHIFT TO EVALUATE FURTHER.
BY SATURDAY NIGHT-EARLY SUNDAY...AS UPPER LOW SHIFTS EAST AND MUCH
COLDER AIR FILTERS SOUTH...THINKING CENTRAL KS COULD SEE A PERIOD OF
LIGHT SNOW. CURRENT INDICATIONS SUGGEST HEAVIEST SNOW WILL REMAIN
OFF TO THE NORTH/NORTHWEST...BUT PORTIONS OF CENTRAL KS COULD
RECEIVE UP TO 1 INCH OR SO AFTER MIDNIGHT SATURDAY NIGHT THROUGH
SUNDAY MORNING. SUNDAY WILL LIKELY BE THE COLDEST DAY OF THE NEXT
7-10 DAYS...WITH HIGHS IN THE 30S-40S AND A STOUT NORTH WIND.
GIVEN CURRENT MODEL CONSENSUS...CONFIDENCE IS MODERATE TO HIGH THAT
DRY AND WARMING CONDITIONS WILL PREVAIL MONDAY THROUGH NEXT
WEEKEND...AS MID/UPPER FLOW FLATTENS OUT SOME AND ATMOSPHERIC
HEIGHTS/THICKNESS INCREASES. HIGHS IN THE 50S-60S APPEAR LIKELY.
ADK
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 52 62 35 40 / 70 80 40 30
HUTCHINSON 52 63 33 39 / 70 70 40 40
NEWTON 51 61 33 38 / 70 80 50 40
ELDORADO 51 60 35 41 / 70 80 50 30
WINFIELD-KWLD 52 61 37 42 / 70 80 50 20
RUSSELL 52 65 29 38 / 50 50 60 60
GREAT BEND 53 67 30 39 / 50 50 60 60
SALINA 52 63 32 38 / 60 70 50 50
MCPHERSON 52 63 32 38 / 70 70 50 50
COFFEYVILLE 53 61 44 46 / 50 90 70 30
CHANUTE 51 59 42 44 / 50 90 70 40
IOLA 50 59 41 44 / 50 90 70 40
PARSONS-KPPF 52 60 42 45 / 50 90 70 30
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1005 PM EDT SUN MAR 10 2013
.Forecast Update...
Issued at 1005 PM EST Sun Mar 10 2013
Rain band is progressing slowly eastward across the western forecast
area. Dewpoints have been slow to come up over the eastern half, but
that should change as this batch of moisture aloft saturates the
lower levels. Expect the rain shield to expand as we get a low level
surge of winds overnight. Latest RAP indicating between 45-55 knots
at 2 kft. Diffluent flow aloft will combine with these low level
winds to create additional rains. Did not make any changes to the
pops, but did bring the near term grids closer to current values.
These changes are transparent in the zones, so not sending out a
zone update at this point. Still looking for areal averages for rain
between an inch and an inch and a half by Monday evening.
&&
.Short Term (Now - Monday Night)...
Issued at 300 PM EDT Sun Mar 10 2013
The approaching surface low continues to strengthen as the
upper-level trough is amplifying over the central CONUS. The surface
low, currently across the Middle Mississippi River Valley, will move
north-northeast to Lake Michigan by Monday morning. This more
northward movement of the surface low will cause the frontal
boundary to slowly progress eastward.
Under cloudy skies, a few sprinkles were present this morning. This
quickly dissipated and cloud cover began to break up by late
morning. This has allowed temperatures to range from the mid 60s to
low 70s early this afternoon, with a little more warming possible.
Southerly winds have also increased across the region, in response
to the strengthening pressure gradient. Gusts have reached the low
to mid 30 mph range, mainly across our southwest CWA (Bowling Green
region) and believe a few more hours of gusts similar to this will
be possible. Lighter wind gusts will be possible across the east and
northeast forecast area.
By this evening, the frontal boundary will approach from the west.
Widespread rain, moderate at times, will move across the western
forecast area late this evening, the central forecast area during
the early morning hours to about daybreak, and across the eastern
forecast area from about daybreak through midday Monday. Expect
precipitation efficient rainfall, as warm-cloud depths range between
8-9K feet, total PWs range between 1 and 1.2 inches, and sub-cloud
layer relative humidity will be 70+ percent. Still looking for
0.75-1.4 inches of rainfall for overall QPF, with the higher amounts
being across south-central Kentucky. This should not cause may
issues, with just some nuisance ponding/flooding and rises on area
rivers and streams. Some low-top showers could develop on the back
side of the departing main precip shield Monday afternoon and exit
the eastern forecast area during the evening hours. Will continue
PoPs Monday afternoon and trend them back from west to east, ending
PoPs around midnight in the east. Still appears showers could mix
down some stronger, sub-severe winds. So, winds of 40 mph are
possible, especially with already strong gradient winds.
Strong gusty winds will subside a bit tonight and transition to
westerly Monday afternoon and evening, as the front pushes through
the forecast area. Expect non-diurnal temperature trends Sunday
night and Monday as colder air filters southeast across the forecast
area. Temperatures will be quite mild tonight, with readings ranging
from the low to mid 50s. Temperatures will trend cooler from
northwest to southeast through the day Monday, with generally low 40
in the northwest to around 50 in the southeast expected by early
Monday evening. Temperatures will continue to cool Monday night,
with lows in the lower 30s anticipated.
.Long Term (Tuesday Night through Sunday)...
Issued at 340 PM EDT Sun Mar 10 2013
Tuesday Night through Thursday Night...
The medium range models are in fairly decent agreement for the
middle of the week. The multi-model consensus is in agreement that
a fairly stout upper trough will push through the region around
mid-week bringing colder than normal temperatures back into the
region. Within the upper trough, the models continue to struggle
with bringing a mid-level vorticity max through the base of the
trough. Using the consensus mean, it appears that this feature will
most likely pass to our north and just bring some clouds down into
the region Wednesday afternoon and evening. The upper trough will
shift to the east on Thursday as some mid-level ridging builds to
the west of the area. We will remain in a northwesterly flow aloft
and will be watching for another mid-level vort max to swing through
the region Thursday night. The timing of this vort max is very much
in question as the deterministic models continue to have timing
issues. Yesterday`s solutions showed the GFS being more progressive
and faster, but today`s solutions show a faster Euro and slower
GFS. For now, will keep some low chc PoPs in for Thursday night
until some better forecast/model continuity.
As for temperatures, the multi-model consensus has trended a little
cooler over the last 24 hours. Therefore, it appears that going a
little cooler on temperatures is probably a good bet at this point,
but nothing too earth shattering. Lows Tuesday and Wednesday night
will cool into the 20s. Highs Tuesday will probably only warm into
the lower 40s in the north with lower-middle 40s in the south. A
little bit of a warm up is expected Thursday with readings warming
into the upper 40s in the north and lower 50s in the south. Lows
Thursday night look to cool back into the mid 30s.
Friday through Sunday...
The long term portion of the forecast can be summed up as a low
confidence forecast at best given the large amount of spread in
today`s deterministic guidance. Utilizing an average of the
multi-model consensus, the upper ridge over the east looks to
eventually get replaced with a broad trough as we get toward the end
of the forecast period. The Euro and GFS both handle the mid-level
wave differently and with different speeds. The GFS lets the wave
slide east and results in a quasi-stationary boundary remaining over
the region from this weekend and into next. On the other hand, the
Euro has been trending with pushing the system on through with the
boundary setting up to our south with a more significant system
developing just beyond the forecast period. Interestingly enough,
the pattern is almost reminiscent of the system that passed through
the Mid-Atlantic last week...though the Euro solutions are a little
more to the south of last weeks track. For now, plan on leaving
conditions partly to mostly cloudy through the period. Will
maintain some low chance PoPs in the forecast but hold off on making
more significant adjustments until some better forecast convergence
emerges.
Temperatures are equally challenging as well. The overall pattern
does support above normal temperatures with highs on Friday warming
into the upper 50s to the lower 60s. Saturday could be a bit warmer
with readings in the lower to middle 60s. Depending on the eventual
frontal position, we trended temperatures back a bit on Sunday and
have gone with a more consensus blend here which results in
temperatures in the middle to upper 50s. Overnight lows through the
period will likely average in the 40s.
&&
.Aviation (00Z TAF Issuance)...
Issued at 725 PM EDT Sun Mar 10 2013
Surface low pressure center now over northwest Illinois, with a
second low over east Missouri. The gradient ahead of this feature
will keep steady southerly winds overnight, though less gusty than
what we had during the afternoon. Winds aloft will surge over the
next couple of hours, making for some low level wind shear for most
of the night. Rains will bring some kind of MVFR conditions, for now
have gone with lower visibilities given upstream obs. The cold front
associated with the low will swing through the terminals around
daybreak, bringing lesser winds aloft as well as at the surface.
Ceilings will drop as well, possibly into the IFR range, but have
focused on the earlier hours in this TAF with the LLWS potential.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........RJS
Short Term.......MJP
Long Term........MJ
Aviation.........RJS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
934 PM EDT SUN MAR 10 2013
.SYNOPSIS...
HIGH PRESSURE WILL BRING DRY WEATHER THROUGH EARLY MONDAY. A COLD
FRONT WILL MOVE ACROSS THE REGION LATE MONDAY AND MONDAY NIGHT...
WITH A RETURN TO BELOW AVERAGE TEMPERATURES BY MID WEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
MESO DATA SHOWS UPR LVL RDG BEGINNING TO SHIFT EWD. EVE RAOBS SHOW
WRM AIR ADVCTN PATTERN AND INCRG MID AND HI LVL RH/CLD CVR...SO
INCRD LOW TEMPS FOR THE LT EVE UPDT. A CDFNT WL APRCH THE RGN MON
AFTN. SHRA CHCS WL BE INCRG AHEAD OF THE FNT ESP IN THE AFTN...AND
MAINLY W OF PIT. SLOWED ONSET OF SHRA SOME WITH H5 FLOW
PERPENDICULAR TO THE FNT...WHICH SHOULD SLOW ITS EWD SPEED. INCRD
MAX TEMPS A LTL AS WELL WITH DELAYED ONSET OF SHRA.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/...
EXPTG SHRA WITH FROPA MON EVE/OVRNGT. COLD AIR ADVCTN WL BEGIN AFT
FROPA WITH LOW CHCS FOR PCPN. CRITICAL THICKNESSES/PROFILES
INDICATE SHRA MAY MIX WITH SHSN TUE. HIGH TEMPS ARE EXPD TO DROP
BLO SEASONAL AVGS AGAIN TUE.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
COLD NW FLOW AND AN UPR LVL TROF WL BRING INCRG SHSN CHCS TO THE
RGN THRU WED. SFC HI PRES GRDLY BLDS IN THU AND THU NGT. A WK SFC
LOW IS EXPD TO QUICKLY TRACK SEWD ACRS THE OH VLY RGN FRI...WITH A
CHC FOR SHRA/SHSN MAINLY S OF PIT. A QUASI STNRY FNT IS EXPD TO
SET UP ACRS THE OH/TN VLY RGNS OVR THE WK END...CONTG THE CHC FOR
SHRA/SHSN MAINLY S OF PIT. TEMPS EXPD TO REMAIN BLO SEASONAL AVGS
THRU THE PD.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
VFR WEA WL CONT THRU MONDAY...HOWEVER...LLWS WL BE A CONCERN LATE
TNGT AND EARLY MONDAY AS DEEPENING LOW PRES DVLPS TWD THE WRN GREAT
LAKES. LATEST NAM AND RAP MDL SNDINGS INDICATE SUFFICIENT
ENHANCEMENTMENT OF THE LLVL JET TO ADD A WIND SHEAR MENTION FOR THE
OVRNGT HRS IN ALL...BUT ERNMOST TAF SITES.
THIS STRONG WARM ADVCTN REGIME SHOULD CAP THE BNDRY LYR...AND THUS
LIMIT GUSTS ON MONDAY. 20 TO 25 KT SFC GUSTS WL SUFFICE FOR THE
CURRENT PROGNOSIS.
.OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/...
THE CDFNT EXTENDING FM THE AFOREMENTIONED GREAT LAKES LOW IS
FORECAST FOR A MONDAY NGT CROSSING OF THE UPR OH VALLEY.
RESTRICTIONS IN SHRA SHOULD BE ANTICIPATED WITH THAT PASSAGE...AND
IN THE COLD ADVCTN REGIME BEHIND A REINFORCING FRONT PROJECTED FOR
TUESDAY.
HIGH PRES IS EXPECTED TO RTN GENL VFR TO REGIONAL PORTS FOR LTR
THURSDAY AND FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
07/15
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1238 AM EST SAT MAR 9 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 431 PM EST FRI MAR 8 2013
WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW DOMINATING
NAMERICA. IN THE SRN STREAM...POTENT LOOKING SHORTWAVE HAS MOVED
ONSHORE OVER SRN CA WHILE ANOTHER WAVE IS DROPPING S OVER WRN OR/NRN
CA. BOTH OF THESE WAVES WILL PLAY A ROLE IN THE WX ACROSS THE GREAT
LAKES IN THE COMING DAYS. DOWNSTREAM OF THE WRN TROF...RIDGING IS
OVER THE CNTRL CONUS. TO THE N...ONE SHORTWAVE IS TRACKING THRU NRN
ONTARIO. ANOTHER WAVE IS DROPPING SE INTO ALBERTA ON THE PERIPHERY
OF POLAR VORTEX CENTERED JUST N OF HUDSON BAY. THIS WAVE WILL ALSO
PLAY A ROLE IN THE WX OVER THE GREAT LAKES IN THE COMING DAYS.
CLOSER TO HOME...LOW CLOUDS HAVE LINGERED OVER THE ERN FCST AREA IN
SRLY FLOW OFF LAKE MI. HOWEVER...RECENTLY...ONLY A SMALL AREA OF
STRATOCU REMAINS...STREAMING ONSHORE IN SRN SCHOOLCRAFT COUNTY.
ELSEWHERE...EARLY MARCH SUNSHINE IS DOING ITS JOB ON THE LOWER
ALBEDO FORESTED LAND OF THE U.P. TEMPS HAVE PUSHED INTO THE 40S AT A
NUMBER OF OBS SITES OVER WRN UPPER MI.
IN THE SHORT TERM...QUIET WX TONIGHT WILL GIVE WAY TO INCREASING
PCPN CHANCES SAT UNDER STRENGTHENING WAA REGIME AHEAD OF NRN STREAM
WAVE THAT WILL BE MOVING INTO SRN MANITOBA/ND AND SRN STREAM WAVE
EMERGING OVER THE SRN HIGH PLAINS. TONIGHT...SRLY FLOW WILL BE ON
THE INCREASE AHEAD OF THE AFOREMENTIONED SHORTWAVES. THERE IS THE
USUAL CONCERN UNDER SRLY FLOW THAT LOW CLOUDS MAY DEVELOP. IN THIS
CASE...HOWEVER...THE NAM AND GFS SHOW DRY AIR ADVECTION TONIGHT AT
THE LOW-LEVELS AS TRAJECTORIES STILL HAVE SUFFICIENT COMPONENT
EMANATING FROM RETREATING HIGH PRES. SO...LOW CLOUDS MAY NOT REALLY
BE AN ISSUE TONIGHT. IF ANY VERY LOW/SHALLOW STRATUS DOES DEVELOP...
IT SHOULD ONLY BE IN THE AREAS WITH BEST UPSLOPING OVER CNTRL UPPER
MI. OTHERWISE...EXPECT GENERALLY PARTLY CLOUDY SKIES IN THE
EVENING...AND THEN AN INCREASE IN HIGH CLOUDS OVERNIGHT. TYPICAL FOR
THIS TYPE OF INITIALLY RATHER WEAK SRLY FLOW...EXPECT LOWEST MINS
NEAR THE BAY OF GREEN BAY AS ICE COVER ENHANCES COOLING AND
STRENGTHENS NOCTURNAL INVERSION IN THAT AREA. LOWS SHOULD BE AROUND
20F THERE.
ON SAT...UNDER STRONG WAA AND ISENTROPIC ASCENT (295K SFC)...EXPECT
PCPN TO DEVELOP FROM W TO E AS LOW-LEVEL DRY AIR IS EVENTUALLY
OVERCOME. TRAJECTORIES SUGGEST THERE WILL BE SOME MAINTENANCE
OF THE LOW-LEVEL DRY AIR OVER THE E EVEN AS FORCING AND RESULTING
PCPN ALOFT OVERSPREAD THAT AREA. SO...POPS WILL SHOW A GRADIENT FROM
CATEGORICAL W TO JUST CHC E LATE. IT`S QUITE POSSIBLE THE E MAY
NOT SEE ANY PCPN SAT. AS FOR PTYPE...IT`S A CHALLENGE AS IT ALMOST
ALWAYS IS WHEN IT`S NOT COLD ENOUGH FOR JUST SNOW OR WARM ENOUGH FOR
JUST RAIN. THERE WILL BE THE USUAL BATTLE BETWEEN STRONG WAA AND THE
COOLING IT GENERATES THRU ASCENT AS WELL AS EVAPORATIVE COOLING
EARLY ON. BELIEVE THE EVAPORATIVE COOLING EARLY ON WILL LEAD TO
PREDOMINANTLY SNOW AS THE PTYPE INITIALLY. THEREAFTER...FCST
SOUNDINGS SHOW PROFILE GENERALLY HOVERING AROUND 0C IN THE LOWER
LEVELS...FLUCTUATING BASED ON ASCENT/PCPN INTENSITY. MEANWHILE...THE
NEAR SFC LAYER MAY RESPOND A LITTLE TO DAYTIME HEATING...PUSHING THE
ODDS TOWARD RAIN. AT THIS POINT...WILL INCLUDE SNOW AS THE GENERAL
PREVAILING PTYPE IN MOST AREAS WITH A MENTION OF RAIN. INCLUDED FZRA
AS WELL WHERE TEMPS ARE AROUND FREEZING. IF THERE IS FZRA...IT
SHOULD BE CONFINED TO THE MORNING/EARLY AFTN BEFORE SURFACES RESPOND
TO WEAK DAYTIME HEATING. WITH TEMPS PUSHING INTO THE MID 30S...
WET/SLUSHY SNOW ACCUMULATIONS WILL BE MINOR...MAYBE AROUND AN INCH.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 431 PM EST FRI MAR 8 2013
SATURDAY NIGHT...
THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE EVOLUTION OF THE
SYOPTIC PATTERN WITH A PROGRESSIVE PATTERN AND LITTLE PHASING
BETWEEN THE NRN STREAM MID LEVEL TROUGH MOVING THROUGH NRN ONTARIO
AND THE NRN GREATLAKES AND THE SRN STREAM SHORTWAVE MOVING EAST FROM
THE PLAINS.
ABUNDANT MOISTURE INFLOW WITH MODERATE TO STRONG 285K-300K
ISENTROPIC LIFT AND A PERIOD OF 700-600 MB FGEN SHOULD SUPPORT A
BAND OF PCPN THROUGH THE CWA...ESPECIALLY BTWN 00Z-06Z WITH QPF
AMOUNTS TO AROUND 0.25 INCH. CONFIDENCE IS ALSO HIGHER THAT A
SIGNIFCANT (1C TO 3C) WARM LAYER WILL SPREAD THROUGH MOST OF THE CWA
GIVEN STRONG WAA WITH SW 40-45 KT 850 MB WINDS BY 00Z/SUN. GENERALLY
UTILIZED NAM/GEM LOW LEVEL THERMAL PROFILE TO DELINEATE PCPN TYPE
PATTERN. WITH ENOUGH WARMTH LINGERING FROM DAYTIME HEATING...ANY SFC
COLD LAYER WILL BE LESS PRONOUNCED LIMITING POTENTIAL FOR FZRA.
SO...MAINLY RA/SN MIX EXPECTED WITH THE GREATEST SNOW CHANCES OVER
THE WEST HALF. WITH LOW SLR AOB 10/1...ANY WET SNOWFALL AMOUNTS
SHOULD ONLY AMOUNT TO AN INCH OR TWO AT MOST.
SUNDAY...THERE WERE GREATER MODEL DIFFERENCES AS THE GFS ALLOWS
ANOTHER DEFORMATION BAND OF PCPN TO LIFT INTO UPPER ASSOCIATED WITH
THE SRN STREAM SHRTWV. SINCE THE GLOBAL GEM/ECMWF CONTINUE TO SHOW A
MORE PROGRESSIVE SOLUTION...THE FCST CONTINUES WITH THE IDEA OF
TAPERING OFF POPS/QPF FROM WEST TO EAST WITH MAINLY JUST CHANCE POPS
BY AFTERNOON. SOME LAKE ENHANCED SNOW MAY DEVELOP BUT WITH THE
SYNOPTIC SCALE UPWARD MOTION AND DEEPER MOISTURE DEPARTING...ANY
AMOUNTS SHOULD BE LIGHT.
SUN NIGHT INTO MON...850 MB TEMPS DROPPING INTO THE -12C TO -14C
ALONG WITH CONTINUED CYCLONIC NRLY FLOW COULD STILL SUPPORT SOME
LES. HOWEVER...WITH STRONG 850-700 MB DRYING...ANY AMOUNTS
ARE EXPECTED TO BE LIGHT
TUE-FRI...MDLS WERE CONSISTENT WITH A WEAK CLIPPER SHORTWAVE AND SFC
TROUGH MOVING THROUGH THE UPPER GREAT LAKES MON NIGHT INTO TUE. THE FAVORED
ECMWF REMAINED MORE AMPLIFIED WITH THE ERN GREAT LAKES TROUGH BY WED
WITH COLDER AIR AVAILABLE FOR SOME NW FLOW LES COMPARED TO THE THE
GFS. CONFIDENCE IN DETAILS DROPS OFF BY THU-FRI WITH REGARD TO THE
POSITION/STRENGTH OF THE NEXT SHORTWAVE THAT COULD BRING SNOW CHANCES
INTO THE REGION. TEMPS SHOULD REMAIN AT OR BELOW SEASONAL AVERAGES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1237 AM EST SAT MAR 9 2013
EXPECT VFR CONDITIONS TO PREVAIL THRU SUNRISE GIVEN DRYNESS OF
UPSTREAM AIRMASS TO THE S AND A STEADY S WIND ON THE WRN FLANK OF
RETREATING HI PRES OVER SE LWR MI THAT IS LIMITING THE POTENTIAL FOR
FOG FORMATION. AN APRCHG LO PRES TROF WL BRING AN INCRSG THREAT W-E
OF SOME SN OR MIXED RA/SN DURING THE LATE MRNG/AFTN ON SAT.
LINGERING LLVL DRYNESS WL SLOW DOWN THE ONSET OF LOWER CIGS/
VSBY...BUT THESE CONDITIONS SHOULD DVLP WITH PERSISTENT PCPN/
MOISTENING. THE BEST SHOT AT IFR OR EVEN LIFR WX WL BE AT CMX...
FARTHER FM DEPARTING LLVL DRY AIR AND WHERE NEAR SFC SE FLOW WL
UPSLOPE.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 431 PM EST FRI MAR 8 2013
SOUTHERLY FLOW WILL DOMINATE TONIGHT THRU SAT EVENING AHEAD OF AN
APPROACHING LOW PRES TROF. TYPICAL FOR SOUTHERLY FLOW...STRONGEST
WINDS WILL BE OVER ERN LAKE SUPERIOR...REACHING UPWARDS OF 30KT SAT
AFTN/EVENING. TROF WILL THEN PASS ACROSS LAKE SUPERIOR LATE SAT
NIGHT/SUN...BRINGING A SHIFT TO 20-30KT NW WINDS. WINDS WILL THEN
SLOWLY SUBSIDE LATE SUN NIGHT/MON...FALLING TO UNDER 15KT FOR MON
NIGHT/TUE. MAY SEE A SLIGHT INCREASE IN WINDS WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...JLB
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
854 PM CDT SUN MAR 10 2013
.UPDATE...
UPDATE ON EXPANSION OF WINTER STORM WARNING.
&&
.DISCUSSION...
WINTER STORM BEGINNING TO TAKE SHAPE THIS EVENING AS SFC LOW MOVES
INTO THE QUAD CITIES. LAST FEW RUNS OF THE RAP HAVE BEEN REALLY
UNLOADING WITH HEAVY SNOW FROM CENTRAL FARIBAULT COUNTY...UP TO
OWATONNA...LAKE CITY...AND EAU CLAIRE/CHIP FALLS. WITH THE RAP AND
HRRR COMING IN A BIT FARTHER NW WITH THE HEAVIER SNOW...TACKED ON
A FEW MORE COUNTIES TO THE WARNING...WITH SLIGHTLY HIGHER AMOUNTS
EXPECTED AS WELL IN THE ALBERT LEA AND EAU CLAIRE AREAS.
CURRENT RADAR SHOWING A RATHER STRONG BAND SETTING UP FROM NEAR
THE CITY OF BLUE EARTH UP TOWARD LAKE CITY. AT TIMES HAVE SEEN
KAEL AND KTOB GO DOWN TO A HALF MILE VIS WITH THIS BAND
OVERHEAD...AND A CALL TO FARIBAULT COUNTY REVEALED 2 INCHES ALREADY
IN THE CITY OF BLUE EARTH. BASED ON THE RAP/SPC MESO
ANALYSIS...THIS LOOKS TO BE THE RESULT OF A COMBO OF FGEN AROUND
THE H85 LAYER...ALONG WITH STRONG MOISTURE TRANSPORT WITHIN THE
COLD CONVEYOR BELT TO THE NORTH OF THE SFC LOW. THIS IS HEAVIER
BAND 1 OF 2 THAT THE RAP HAS FOR SE MN...WITH TOTAL QPF FROM BLUE
EARTH...UP THROUGH DODGE CENTER...LAKE CITY...AND EAU CLAIRE
BETWEEN 0.85" AND 0.95"...WHICH RESULTS IN A FAIRLY HEALTHY REGION
OF 8 TO 10 INCHES OF SNOW.
BAND 2 MENTIONED ABOVE SETS UP JUST EAST OF THE FIRST BAND LATER
TONIGHT AND WILL PRIMARILY IMPACT THE ARX AREA. THIS BAND IS
ASSOCIATED WITH PV ADVECTION TO THE WEST OF THE MAIN PV ANOMALY
WHICH THE RAP TAKES FROM AROUND IOWA CITY UP TOWARD WAUSAU. THE
11.23 RAP HAS SLIGHTLY HIGHER QPF AMOUNTS UP AROUND 1 INCH IN THIS
AREA...WHICH WOULD INDICATE THE POTENTIAL FOR AMOUNTS OF A FOOT OR
MORE.
WHAT MAKES THIS A TRICKY SYSTEM TO FORECAST IS THE VERY TIGHT
GRADIENT IN SNOWFALL AND AMOUNTS THAT IS EXPECTED TO THE NORTHWEST
OF THE HEAVY BAND OF SNOW. FOR INSTANCE...ACROSS GOODHUE
COUNTY...LATEST UPDATE TO GRIDS HAS AROUND 8 INCHES ALONG THE
WABASHA COUNTY LINE IN THE SOUTH...WITH AMOUNTS NEAR 4 INCHES
ALONG THE DAKOTA COUNTY LINE TO THE NORTH. WITH THE SLIGHT
NORTHWESTWARD SHIFT IN THE HEAVIER SNOW AMOUNTS...THIS PULLED THE
6+ INCH AMOUNTS A LITTLE FARTHER NORTHWEST. FOR THE COUNTIES ADDED
/WASECA...STEELE...GOODHUE...PIERCE...DUNN...AND CHIPPEWA WI/...IT
IS BASICALLY THE SOUTHEAST HALF OR LESS OF THESE COUNTIES WHERE
AMOUNTS OF 6 INCHES OR MORE ARE EXPECTED. WITH THE TIGHT GRADIENT
IN SNOW...DID NOT SEE THE NEED TO ADD ANY COUNTIES TO AN ADVY. FOR
EXAMPLE...IN DAKOTA COUNTY...HAVE SNOWFALL AMOUNTS RANGING FROM A
TRACE ALONG THE HENNEPIN/RAMSEY COUNTY LINE TO NEAR 4 INCHES ALONG
THE GOODHUE COUNTY LINE. OTHER COUNTIES BORDERING THE WARNING SHOW
SIMILAR GRADIENTS...SO DID NOT ADD ANY COUNTIES TO AN ADVY. IF
ANYTHING...COUNTIES STILL IN THE ADVY WILL BE CLOSE TO WARNING
TYPE SNOWS IN THE FAR SOUTHEAST TIPS OF THOSE COUNTIES. KIND OF AN
ALL OR NOTHING SCENARIO HERE!
WILL BE SEEING SOME INTENSE SNOWFALL RATES TONIGHT ON THE ORDER OF
1 TO 2 INCHES PER HOUR AS WELL /SEE NESDIS SATELLITE PRECIP
ESTIMATE PRODUCT AND SPC MESO DISCUSSION #269/. BY MONDAY
MORNING...THE INTENSE SNOWFALL WILL START LETTING UP...WITH LIGHT
SNOW LINGERING INTO THE AFTERNOON...ESPECIALLY ACROSS WI. SNOW
WILL LIKELY CONTINUE BEYOND CURRENT END TIME OF HEADLINES...THOUGH
ACCUMULATING SNOWS SHOULD BE ALL BUT DONE BY NOON...BUT A POSSIBLE
EXTENSION IN TIME WILL NEED TO BE CONSIDERED BY LATER SHIFTS.
BEHIND THIS SYSTEM...IT WILL BE COOL THROUGH THE MIDDLE OF THE
WEEK AS HIGH PRESSURE SETTLES IN. TUESDAY LOOKS TO BE THE COLDEST
DAY NEXT WEEK. WITH THE COLD UPPER TROUGH OVERHEAD...THIS WILL
CREATE STEEP LAPSE RATES WITH DAYTIME HEATING AND LIKELY SOME
BOUTS OF SNOW SHOWERS...THOUGH NO ACCUMULATIONS ARE EXPECTED.
FOR THE SECOND HALF OF THE WEEK...A MODERATION IN TEMPERATURES BACK
TOWARD NORMAL /WHICH ARE ALREADY PUSHING 40 ON THE HIGHS/ IS
EXPECTED AS UPPER RIDGING BUILDS EAST FROM THE ROCKIES.
FOR NEXT WEEKEND AND BEYOND...THERE IS NOT MUCH CONFIDENCE IN THE
FORECAST AS THE ECMWF AND THE GFS SIT ABOUT 180 DEGS APART FROM
EACH OTHER. FOR NEXT WEEKEND INTO THE FOLLOWING WEEK...THE ECMWF
HAS THE DEEP THROUGH OVER ERN NOAM...WITH A SHARP RIDGE OVER THE
ROCKIES...WHICH OPENS THE DOOR FOR MORE MODIFIED ARCTIC AIR. THE
GFS ON THE OTHER HAND GOES RIDGING EAST AND TROUGHING WEST AND
BRINGS ANOTHER WARM WET SYSTEM INTO THE UPPER MS VALLEY AT THE END
OF NEXT WEEKEND INTO THE FOLLOWING WEEK. BASED ON PAST
PERFORMANCE...THE GFS IS LIKELY A BIT TOO AGGRESSIVE WITH BREAKING
DOWN THE WRN RIDGE NEXT WEEKEND.
&&
.AVIATION.../00Z TAF ISSUANCE/
BAND OF SNOW HAS COMMENCED FROM SOUTH CENTRAL MN NORTHEAST TOWARD
EAU CLAIRE WI. KEAU WILL BE THE MAIN SITE THAT EXPERIENCES SNOW
AND REDUCED VISIBILITIES TO NEAR 1/2SM AT TIMES THROUGH TONIGHT.
KRNH AND KMSP WILL BE ON THE NORTHERN FRINGES OF THE AREA OF
SNOW...WITH A SHORT WINDOW OF MVFR VSBYS AND LIGHT SNOW POSSIBLE
THIS EVENING. REGARDLESS OF WHERE IT SNOWS...CIGS WILL REMAIN MVFR
THROUGH THE NIGHT...WITH POSSIBLY THE EXCEPTION OF KAXN WHERE SOME
BREAKS IN THE LOW CLOUDS ARE POSSIBLE TOWARD MORNING. NORTHERLY
WINDS WILL REMAIN IN THE 12 TO 15 KT RANGE TONIGHT...WITH GUSTS TO
AROUND OR JUST ABOVE 20 KTS POSSIBLE AT KMSP/KRNH/KEAU THIS
EVENING. CIGS WILL GRADUALLY IMPROVE TO VFR FROM WEST TO EAST ON
MONDAY...WITH VFR CONDITIONS EXPECTED AT ALL SITES /EXCEPT KEAU/
BY MID AFTERNOON MONDAY.
KMSP...
IT WILL BE A CLOSE CALL WHETHER KMSP SEES SNOW THIS
EVENING...ALTHOUGH CONFIDENCE IS RELATIVELY HIGH THAT IF SNOW IS
OBSERVED...THE VSBY WILL BE AROUND OR ABOVE 4SM. HIGHER CONFIDENCE
IN THE CIG STAYING LOW-END MVFR THROUGH TONIGHT. EXPECT THE HEIGHT
TO BE AROUND 1700 FT THROUGH THE EVENING...THEN A GRADUAL INCREASE
TO AROUND 2000 FT BY DAYBREAK MONDAY. SHOULD SEE A BROKEN CIG
DEVELOPING AROUND 18Z...WITH VFR BY 21Z AND THE PRIMARY DECK
BECOMING MID TO HIGH LEVEL /CIRCA 12KFT/. SUSTAINED NORTH WINDS
AROUND 13-14KTS WILL CONTINUE GUSTING TO AROUND OR JUST ABOVE 20
KTS THIS EVENING...THEN LOSE THE GUSTINESS OVERNIGHT AND BACK A
BIT TO AROUND 340 DEGREES BY DAYBREAK. WINDS WILL BACK FURTHER
THROUGHOUT THE DAY MONDAY..TO AROUND 290 DEGREES BY 21Z.
/OUTLOOK FOR KMSP/
TUE...MVFR CIGS/VSBYS POSSIBLE WITH -SN. NW WIND 10 TO 15 KTS.
WED...VFR. NW WIND 5 TO 10 KTS BACKING TO SOUTH.
THU...VFR. S WIND AROUND 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 7 AM CDT MONDAY FOR FARIBAULT-
FREEBORN-GOODHUE-STEELE-WASECA.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT MONDAY FOR BLUE EARTH-
MARTIN-RICE.
WI...WINTER STORM WARNING UNTIL 10 AM CDT MONDAY FOR CHIPPEWA-DUNN-
EAU CLAIRE-PEPIN-PIERCE.
WINTER WEATHER ADVISORY UNTIL 10 AM CDT MONDAY FOR RUSK.
&&
$$
MPG/LS
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
602 AM EST SAT MAR 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE CLEAR SKIES AND MODERATING TEMPERATURES
THROUGH THE WEEKEND. A COLD FRONT IS EXPECTED TO APPROACH THE REGION
MONDAY NIGHT AND BRING THE AREA SCATTERED RAIN SHOWERS BY LATE MONDAY
AFTERNOON. TEMPERATURES WILL FALL BACK TO MORE SEASONAL VALUES BY
THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
6 AM UPDATE...
QUICK UPDATE TO ADD IN LOW STRATUS OVR FINGER LKS AS THAT HAS
DEVELOPED SINCE 08Z UNDER CALM WINDS AND LWRNG DWPT DEPRESSIONS.
EXPECT BY THE TIME MIXING STARTS LOW CLOUDS SHUD SCATTER OUT AND
LEAVE A SUNNY DAY ON TAP.
PREV DISCO BLO...
330 AM UPDATE...
HIPRES WL DOMINATE THE WX TDA. 1030MB SFC HIGH WL BUILD EAST INTO
NERN U.S. THIS AFTN. UPR-LVL RIDGING OCCURRING BTWN H5 LOW SPINNING
OVR WRN ATLANTIC AND DIGGING INTO 4-CRNRS REGION. THIS HIGH ALOFT WL
INFLUENCE THE AREA WX OVR THE WEEKEND AND LEAD TO SUBSIDENCE TDA
WITH SUNNY SKIES EXPECTED.
H9 TEMPS INCRS FM -2C TO -4C TO +3C ACRS NEPA AND NR 0C OVR THE LK
PLAIN. THESE TEMPS WL YIELD HIGHS FM ARND 40F ACRS NRN ZONES TO ARND
50F OVR SRN ZONES. WITH LGT WINDS EXPECTED AND SUNNY SKIES THIS AFTN
DO NOT THINK 50S ARE OUT OF THE QUESTION UNDER STRENGTHENING MARCH
SUN. THUS FOR MAX TEMP GRIDS HV BUMPED LAV NUMBERS UP BY A DEGREE OR
TWO.
HIGH CIRRUS WL BEGIN TO OVRSPRD THE REGION FM THE WEST BY 00Z SUNDAY
PER LATEST GEM CLD FIELDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
330 AM UPDATE...
CIRRUS WL THICKEN UP OVRNGT AS SUN GOES DOWN AND EVENTUALLY LEAD TO
PCLDY SKIES BY 12Z SUNDAY. DEPENDING ON HOW THICK CIRRUS WL BE
POTENTIAL LOOKS TO EXIST FOR RIDGE/VLY SPLIT IN TEMPS WITH FCST MINS
EXPECTED TO BE LWR 20S IN DEEPEST VLYS AND ARND 30 ON RIDGETOPS.
LEE-SIDE CYCLOGENESIS OCCURS THIS WEEKEND AS H5 LOW CROSSES
FRONT-RANGE. UL SYSTEM WL STEER SFC LOW EVER CLSR TO CWA THO WL
STILL RMN FAR ENUF BACK TO OUR WEST ON SUNDAY TO ALLOW HIPRES TO
CONT ITS GRIP ON THE REGION. H5 HEIGHTS APPCHG 570 SUN AFTN WL ALLOW
TEMPS TO RISE INTO THE 50S AREAWIDE. WITH SW FLOW IN THE BL AND H9
TEMPS APPCHG 7C TO 8C IN THE LK PLAIN SUN AFTN CANNOT RULE OUT UPR
50S IN NRN ZONES THUS HV RAISED HIGHS INTO THE MID-50S FOLLOWING
MAV/GMOS NUMBERS.
LATEST MODELS ADVERTISING SLOWING DOWN OF SYSTEM AND DELAY PCPN FM
ENTERING CWA UNTIL MON AFTN AT THE EARLIEST. 12Z EURO AND 00Z NAM12
INDICATE RAIN WL BE DELAYED UNTIL AFT 00Z TUE THUS HV SLOWED TIMING
OF POPS DOWN DRG THE DAY MONDAY WITH ONLY CHC POPS EXPECTED AFT 18Z
MONDAY. SFC BNDRY EXPECTED TO RMN BACK TO THE WEST ON MONDAY WITH
SRLY FLOW WARMING TEMPS TO NR 50 ONCE AGAIN UNDER CLDY SKIES.
MAIN FROPA OCCURS MON NGT/TUE MRNG, THUS HV BUMPED POPS TO 70% DRG
THIS TIME WITH RAIN EXPECTED. QPF AMNTS LOOK TO AVG ANYWHERE FM
0.50-0.75 INCHES BY 12Z TUESDAY PER LATEST EURO THO SLIGHTLY HIGHER
ON 00Z GFS/NAM. TIMING OF FNT WL PLAY A ROLE IN PTYPE WITH DELAYED
FROPA LEADING TO ALL RAIN MON NGT THEREFORE HV BACKED OFF ON RA/SN
MIX UNTIL CLOSER TO 09Z. 00Z EURO IS EVEN SLOWER THAN 12Z RUN BY
ABOUT 6 HRS. TRENDS INDICATING THAT IMPENDING SYSTEM WL SLOW DOWN
EVEN FURTHER AND LATER SHIFTS WL HV TO MONITOR PROGRESS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
330 AM UPDATE...MINOR TWEEKS TO MED RNG BASED ON LATEST HPC
GUIDANCE...BUT OVERALL GIST OF FCST REMAINS UNCHANGED. PREV BLO...
2 PM UPDATE... FOLLOWED HPC GUIDANCE. BEST SHOT FOR PRECIPITATION
WILL COME EARLY IN THE PERIOD AS A COLD FRONT MOVES THROUGH MONDAY
NIGHT. MAY END AS SOME LIGHT SNOW...ESPECIALLY OVER THE HIGHER
TERRAIN EARLY TUESDAY MORNING. PREFERRED THE MORE UNSETTLED HPC
GUIDANCE (MORE EURO BASED) THAN THE GFS. THIS SOLUTION SHOWS A
TROF...COLDER AIR...AND SNOW SHOWERS THROUGH MID-WEEK. THE GFS IS
MORE ZONAL (NORTHWEST FLOW) WITH VARIOUS SHORT WAVES BEFORE A TROF
DEVELOPS IN THE EAST BY THE END OF THE WEEK.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
430 AM UPDATE...AREA OF LOW CLD/STRATUS HAS DVLPD ACRS THE ERN
FINGER LAKES. 1000-950 RUC RH APPEARS TO CAPTURE THIS...SUGGESTING
THAT THE WRN PERIPHERY COULD BRUSH ITH...AND HAVE ADDED POTNL IFR
FOR EARLY THIS MRNG THERE. IF THIS AREA HOLDS TOGETHER AS IT
DROPS SWD IT COULD AFFECT BGM TWDS 12Z. PREV BLO...
330 AM UPDATE...ADDED POTNL FOR IFR AT SYR THIS MRNG AS PATCHY
STRATUS/FOG HAS DVLPD SE OF LAKE ONTARIO. PREV BLO...
VFR WILL PREVAIL THRU 06Z SUN WITH SKC TO BKN250 XPCTD. PATCHY
LOW LVL STRATUS COULD DVLP TWDS DAYBREAK OVER PORTIONS OF CNTRL NY
BUT PROBS TOO LOW TO INCLUDE IN TAFS. WINDS TDA N TO NW 5-10
KTS...BECMG E TO SE TNGT ARND 5 KTS.
.OUTLOOK...
SAT NIGHT/SUN...VFR.
SUN NGT TO MON...MVFR IN -SHRA.
MON NGT TO TUE...MVFR/IFR WITH RAIN CHANGING TO SNOW.
WED...MVFR POSSIBLE ESPECIALLY CNY TERMINALS IN SNOW SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...PVN
NEAR TERM...PVN
SHORT TERM...PVN
LONG TERM...HEDEN
AVIATION...
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
439 AM EST SAT MAR 9 2013
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE CLEAR SKIES AND MODERATING TEMPERATURES
THROUGH THE WEEKEND. A COLD FRONT IS EXPECTED TO APPROACH THE REGION
MONDAY NIGHT AND BRING THE AREA SCATTERED RAIN SHOWERS BY LATE MONDAY
AFTERNOON. TEMPERATURES WILL FALL BACK TO MORE SEASONAL VALUES BY
THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
330 AM UPDATE...
HIPRES WL DOMINATE THE WX TDA. 1030MB SFC HIGH WL BUILD EAST INTO
NERN U.S. THIS AFTN. UPR-LVL RIDGING OCCURRING BTWN H5 LOW SPINNING
OVR WRN ATLANTIC AND DIGGING INTO 4-CRNRS REGION. THIS HIGH ALOFT WL
INFLUENCE THE AREA WX OVR THE WEEKEND AND LEAD TO SUBSIDENCE TDA
WITH SUNNY SKIES EXPECTED.
H9 TEMPS INCRS FM -2C TO -4C TO +3C ACRS NEPA AND NR 0C OVR THE LK
PLAIN. THESE TEMPS WL YIELD HIGHS FM ARND 40F ACRS NRN ZONES TO ARND
50F OVR SRN ZONES. WITH LGT WINDS EXPECTED AND SUNNY SKIES THIS AFTN
DO NOT THINK 50S ARE OUT OF THE QUESTION UNDER STRENGTHENING MARCH
SUN. THUS FOR MAX TEMP GRIDS HV BUMPED LAV NUMBERS UP BY A DEGREE OR
TWO.
HIGH CIRRUS WL BEGIN TO OVRSPRD THE REGION FM THE WEST BY 00Z SUNDAY
PER LATEST GEM CLD FIELDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
330 AM UPDATE...
CIRRUS WL THICKEN UP OVRNGT AS SUN GOES DOWN AND EVENTUALLY LEAD TO
PCLDY SKIES BY 12Z SUNDAY. DEPENDING ON HOW THICK CIRRUS WL BE
POTENTIAL LOOKS TO EXIST FOR RIDGE/VLY SPLIT IN TEMPS WITH FCST MINS
EXPECTED TO BE LWR 20S IN DEEPEST VLYS AND ARND 30 ON RIDGETOPS.
LEE-SIDE CYCLOGENESIS OCCURS THIS WEEKEND AS H5 LOW CROSSES
FRONT-RANGE. UL SYSTEM WL STEER SFC LOW EVER CLSR TO CWA THO WL
STILL RMN FAR ENUF BACK TO OUR WEST ON SUNDAY TO ALLOW HIPRES TO
CONT ITS GRIP ON THE REGION. H5 HEIGHTS APPCHG 570 SUN AFTN WL ALLOW
TEMPS TO RISE INTO THE 50S AREAWIDE. WITH SW FLOW IN THE BL AND H9
TEMPS APPCHG 7C TO 8C IN THE LK PLAIN SUN AFTN CANNOT RULE OUT UPR
50S IN NRN ZONES THUS HV RAISED HIGHS INTO THE MID-50S FOLLOWING
MAV/GMOS NUMBERS.
LATEST MODELS ADVERTISING SLOWING DOWN OF SYSTEM AND DELAY PCPN FM
ENTERING CWA UNTIL MON AFTN AT THE EARLIEST. 12Z EURO AND 00Z NAM12
INDICATE RAIN WL BE DELAYED UNTIL AFT 00Z TUE THUS HV SLOWED TIMING
OF POPS DOWN DRG THE DAY MONDAY WITH ONLY CHC POPS EXPECTED AFT 18Z
MONDAY. SFC BNDRY EXPECTED TO RMN BACK TO THE WEST ON MONDAY WITH
SRLY FLOW WARMING TEMPS TO NR 50 ONCE AGAIN UNDER CLDY SKIES.
MAIN FROPA OCCURS MON NGT/TUE MRNG, THUS HV BUMPED POPS TO 70% DRG
THIS TIME WITH RAIN EXPECTED. QPF AMNTS LOOK TO AVG ANYWHERE FM
0.50-0.75 INCHES BY 12Z TUESDAY PER LATEST EURO THO SLIGHTLY HIGHER
ON 00Z GFS/NAM. TIMING OF FNT WL PLAY A ROLE IN PTYPE WITH DELAYED
FROPA LEADING TO ALL RAIN MON NGT THEREFORE HV BACKED OFF ON RA/SN
MIX UNTIL CLOSER TO 09Z. 00Z EURO IS EVEN SLOWER THAN 12Z RUN BY
ABOUT 6 HRS. TRENDS INDICATING THAT IMPENDING SYSTEM WL SLOW DOWN
EVEN FURTHER AND LATER SHIFTS WL HV TO MONITOR PROGRESS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
330 AM UPDATE...MINOR TWEEKS TO MED RNG BASED ON LATEST HPC
GUIDANCE...BUT OVERALL GIST OF FCST REMAINS UNCHANGED. PREV BLO...
2 PM UPDATE... FOLLOWED HPC GUIDANCE. BEST SHOT FOR PRECIPITATION
WILL COME EARLY IN THE PERIOD AS A COLD FRONT MOVES THROUGH MONDAY
NIGHT. MAY END AS SOME LIGHT SNOW...ESPECIALLY OVER THE HIGHER
TERRAIN EARLY TUESDAY MORNING. PREFERRED THE MORE UNSETTLED HPC
GUIDANCE (MORE EURO BASED) THAN THE GFS. THIS SOLUTION SHOWS A
TROF...COLDER AIR...AND SNOW SHOWERS THROUGH MID-WEEK. THE GFS IS
MORE ZONAL (NORTHWEST FLOW) WITH VARIOUS SHORT WAVES BEFORE A TROF
DEVELOPS IN THE EAST BY THE END OF THE WEEK.
&&
.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
430 AM UPDATE...AREA OF LOW CLD/STRATUS HAS DVLPD ACRS THE ERN
FINGER LAKES. 1000-950 RUC RH APPEARS TO CAPTURE THIS...SUGGESTING
THAT THE WRN PERIPHERY COULD BRUSH ITH...AND HAVE ADDED POTNL IFR
FOR EARLY THIS MRNG THERE. IF THIS AREA HOLDS TOGETHER AS IT
DROPS SWD IT COULD AFFECT BGM TWDS 12Z. PREV BLO...
330 AM UPDATE...ADDED POTNL FOR IFR AT SYR THIS MRNG AS PATCHY
STRATUS/FOG HAS DVLPD SE OF LAKE ONTARIO. PREV BLO...
VFR WILL PREVAIL THRU 06Z SUN WITH SKC TO BKN250 XPCTD. PATCHY
LOW LVL STRATUS COULD DVLP TWDS DAYBREAK OVER PORTIONS OF CNTRL NY
BUT PROBS TOO LOW TO INCLUDE IN TAFS. WINDS TDA N TO NW 5-10
KTS...BECMG E TO SE TNGT ARND 5 KTS.
.OUTLOOK...
SAT NIGHT/SUN...VFR.
SUN NGT TO MON...MVFR IN -SHRA.
MON NGT TO TUE...MVFR/IFR WITH RAIN CHANGING TO SNOW.
WED...MVFR POSSIBLE ESPECIALLY CNY TERMINALS IN SNOW SHOWERS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...PVN
NEAR TERM...PVN
SHORT TERM...PVN
LONG TERM...HEDEN
AVIATION...
AREA FORECAST DISCUSSION
NWS RALEIGH NC
915 PM EDT SUN MAR 10 2013
.SYNOPSIS...
HIGH PRESSURE ALONG THE EAST COAST WILL DRIFT EASTWARD IN ADVANCE OF
A COLD FRONT THAT WILL CROSS CENTRAL NC EARLY TUE.
&&
.NEAR TERM /TONIGHT/...
AS OF 915 PM SUNDAY...
REST OF TONIGHT: BIGGEST CHALLENGE TONIGHT IS HOW MUCH STRATUS WILL
FORM -- IF ANY -- AND WHERE IT WILL BE MOST WIDESPREAD. HIGH
PRESSURE CENTERED JUST OFF THE MAINE COAST AND EXTENDING DOWN THE
EASTERN SEABOARD ACCORDING TO THE LATEST SURFACE ANALYSIS WILL SLIP
SLOWLY EASTWARD OFF THE COAST TONIGHT... RESULTING IN A SLOW BUT
STEADY INFLUX OF ATLANTIC-SOURCE NEAR-SURFACE MOISTURE INTO NC AS
WINDS SWING AROUND TO SOUTHEASTERLY. SURFACE DEW POINTS ACROSS
CENTRAL NC HAVE VARIED WIDELY FOR THE LAST SEVERAL HOURS... FROM
15-20 EAST/CENTRAL TO 25-34 WEST LATE THIS AFTERNOON... AND THIS
WIDE RANGE REMAINS ALBEIT WITH A MARKED INCREASE INTO THE 20S AND
LOW 30S IN THE COASTAL PLAIN... PUSHING THE VALUES IN THE TEENS UP
INTO THE NORTHEAST PIEDMONT. DEW POINTS IN THE UPPER 30S AND 40S ARE
NOT FAR AWAY... RIGHT AT THE COAST AND JUST OFFSHORE... AND I SEE
NOTHING TO SUGGEST THAT THIS HIGHER LOW-LEVEL MOISTURE WILL NOT
CONTINUE TO SURGE INTO THE COASTAL PLAIN OVERNIGHT. THE LATEST RUNS
OF THE RAP SUPPORT THIS ONSHORE SURGE OF MOISTURE... AS DO RECENT
HRRR RUNS WHICH DEPICT RAPID DEVELOPMENT OF LOW CIGS ALONG AND EAST
OF I-95 BEFORE 09Z. WORKING AGAINST SUCH A SCENARIO IS THE RESIDENT
DRY AIR NOTED ON AREA SOUNDINGS... AS LOW LEVELS ARE MORE MOIST AT
MHX/CHS THAN AT GSO BUT NOT INCREDIBLY SO. BUT GIVEN THE STABLE
NEAR-SURFACE LAYER... THE AFTERNOON ABUNDANCE OF STRATOCU JUST OFF
THE CAROLINA COAST... AND WITH A MULTITUDE OF MODELS (INCLUDING BUFR
SOUNDINGS FROM THE NAM AND GFS) SHOWING LOW STRATUS FORMING BY
MORNING ESPECIALLY IN THE EAST... WILL INCREASE SKY COVER ESPECIALLY
IN THE EASTERN HALF OF THE CWA. MOISTURE REMAINS ELEVATED IN THE
WESTERN PIEDMONT AS WELL... AND UPSLOPE FLOW MAY RESULT IN AREAS OF
STRATUS HERE AS WELL... ALTHOUGH TRAJECTORIES SUGGEST THAT THE
ISOLATED POCKET OF DRY SURFACE AIR NOW FOUND OVER INTERIOR SOUTHEAST
NC AND NORTHEAST SC WILL TRANSLATE INTO THIS AREA... LIMITING
STRATUS FORMATION SOMEWHAT. TEMPS HAVE ALREADY DROPPED INTO THE 40S
IN ISOLATED SPOTS BUT 50S REMAIN WIDESPREAD ENOUGH TO JUSTIFY A
SLIGHT UPWARD TICK IN LOWS TONIGHT... GIVEN THE ANTICIPATED CLOUD
DEVELOPMENT. LOWS 39-46. -GIH
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 225 PM SUNDAY...
LEADING EDGE OF A 45-50KT SOUTHERLY LOW-LEVEL JET EMBEDDED IN THE
BROAD WARM AIR CONVEYOR BELT DOWNSTREAM OF THE SYSTEM WILL BEGIN TO
ADVECT GULF MOISTURE NORTHWARD LATE MONDAY AFTERNOON...WHICH WILL
RESULT IN SCATTERED SHOWERS BREAKING OUT OVER THE AREA LATE MONDAY
AFTERNOON/EARLY EVENING. DEEP LAYER FORCING VIA DIFFLUENT FLOW
ALOFT ASSOCIATED WITH A COUPLED JET STRUCTURE ATOP STRONG LOW-LEVEL
MOISTURE FLUX CONVERGENCE ALONG THE SOUTHERLY LOW-LEVEL JET
WILL ARRIVE FROM THE WEST AOA MIDNIGHT MONDAY NIGHT WITH
SIGNIFICANT-WIDESPREAD(CATEGORICAL)CONVECTIVE SHOWERS SPREADING WEST
TO EAST THROUGH THE AREA THROUGH 15Z TUESDAY MORNING BEFORE THIS
SUPPORT MOVES OFFSHORE. THE LOW-LEVEL JET AND ATTENDANT LINE OF
CONVECTION WILL SERVE AS THE EFFECTIVE FRONT WITH ONLY AN ISOLATED
SHOWER EXPECTED WITH THE ACTUAL TRAILING SFC COLD FRONT AS IT MOVES
THROUGH THE AREA BETWEEN 15 TO 21Z TUESDAY. A SOLID ONE QUARTER TO
ONE HALF INCH OF RAINFALL LOOKS TO BE IN ORDER FOR ALL OF CENTRAL
NC.
THUNDER/SEVERE THREAT:
WITH THE STRONG TROUGH DYNAMICS AND LOW-LEVEL KINEMATIC
FIELDS TRAVERSING THE CAROLINAS BETWEEN 06 TO 15Z TUESDAY...
WEAK TO MODEST MID-LEVEL LAPSE RATES OF 5.5 TO 6.0 C/KM--NOCTURNAL
BOUNDARY LAYER COOLING OVERNIGHT ALONG WITH RATHER WIDESPREAD
LOW-LEVEL CLOUD COVER ACROSS THE AREA THROUGH MIDDAY TUESDAY
WILL RESULT IN MEASLY INSTABILITY (100-200 J/KG MUCAPE)ACROSS
EASTERN NC. SO WHILE NOT ZERO...BOTH THUNDER AND A SEVERE THREAT ARE
VERY LOW. WILL NOT INCLUDE A MENTION OF THUNDER AT THIS TIME.
TEMPERATURES:
MILD OVERNIGHT LOWS MONDAY NIGHT GIVEN WIDESPREAD RAIN AND CLOUDS.
LOWS IN THE LOWER 50S NW TO MID-UPPER 50S SOUTHEAST. NOT MUCH
DIFFERENCE IN HIGHS TEMPERATURES FROM MONDAY TO TUESDAY WITH CAA
DELAYED UNTIL TUESDAY NIGHT. AS SUCH...CLOUD COVER WILL BE THE MAIN
DETERMINING FACTOR. HIGHS BOTH DAYS IN THE LOWER 60S NW TO NEAR 70
SOUTHEAST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
AS OF 225 PM SUNDAY...
TO START THE LONG TERM PERIOD...THE COLD FRONT AND ASSOCIATED PRECIP
ARE EXPECTED TO BE EAST OF THE AREA BY EARLY TUESDAY EVENING...WITH
ANY LINGERING CLOUDS ACROSS THE EASTERN PORTIONS OF THE FORECAST
AREA CLEARING SHORTLY AFTER. COLD AIR ADVECTION BEHIND THE DEPARTING
FRONT WILL LEAD TO COOLER OVERNIGHT LOWS...GENERALLY IN THE MID TO
UPPER 30S. THEN...MUCH OF THE PERIOD IS EXPECTED TO BE DOMINATED BY
A BROAD UPPER TROUGH. THIS WILL RESULT IN BELOW NORMAL TEMPS...
ESPECIALLY WED AND THU AS SOME COLD AIR ADVECTION CONTINUES. TEMPS
SHOULD REBOUND SLIGHTLY TO NEAR NORMAL BY THE END OF THE WEEK AND
INTO THE WEEKEND AS HEIGHTS RISE SOME. WITH REGARDS TO ANY PRECIP...
WITH NORTHWESTERLY FLOW ALOFT PERSISTING ACROSS OUR REGION...MODELS
CONTINUE TO PROG SEVERAL DISTURBANCES/CLIPPERS MOVING SOUTHEAST
WITHIN THIS FLOW. HOWEVER...UNCERTAINTY REMAINS HIGH WITH RESPECT TO
EXACT TRACK OF THESE (AND TIMING IN GENERAL) AND WITH MOISTURE
REMAINING RATHER LIMITED...WILL MAINTAIN A DRY FORECAST THROUGH AT
LEAST THE END OF THE WEEK. UNCERTAINTY INCREASES EVEN MORE BY THE
WEEKEND AS MODELS ARE SHOWING A BACKDOOR FRONT IMPACTING THE AREA
(TO VARYING DEGREES). MOISTURE IS PROGGED TO BEGIN TO INCREASE
DURING THIS TIME FRAME AS WELL AND THEREFORE WILL GO AHEAD AND
INTRODUCE SLIGHT CHANCE POPS FOR THE WEEKEND...ALTHOUGH CONFIDENCE
IS FAIRLY LOW.
&&
.AVIATION /00Z MONDAY THROUGH THURSDAY/...
AS OF 805 PM SUNDAY...
UNDER THE INFLUENCE OF RIDGING ALOFT AND UNDERLYING SURFACE HIGH
PRESSURE ALONG THE EAST COAST...VFR CONDITIONS WILL PREVAIL THROUGH
MOST OF TONIGHT. RETURN LOW LEVEL MOISTURE WILL INCREASE LATE
TONIGHT-EARLY MON...AND THIS MOISTURE MAY INDEED SUPPORT THE
DEVELOPMENT OF LOW STRATUS AND/OR FOG AS NWP FORECAST MODELS SUGGEST
BETWEEN 10-14Z. HOWEVER...SUCH A DRY ANTECEDENT AIR MASS -
CHARACTERIZED BY SURFACE DEWPOINTS IN THE TEENS AND 20S OVER CENTRAL
NC THIS EVENING - OPPOSES ANY SUCH STRATUS AND FOG DEVELOPMENT.
GIVEN THE UNCERTAINTY...WILL MAINTAIN FORECAST CONTINUITY FROM THE
18Z TAFS AND CONTINUE WITH A SHORT PERIOD OF MVFR TO IFR CONDITIONS
EARLY MON. OTHERWISE...CONFIDENCE IS HIGHER THAT SAID LOW LEVEL
MOISTURE WILL BE REALIZED OVER THE REMAINDER OF CENTRAL NC IN THE
FORM OF BROKEN STRATOCUMULUS - WITH BASES BETWEEN 3 AND 4 THOUSAND
FEET FROM WEST TO EAST - WITH DIURNAL HEATING MON. CALM TO LIGHT
SOUTHEASTERLY WINDS TONIGHT WILL STRENGTHEN TO BETWEEN 10-15 KTS
MON...WITH OCCASIONAL GUSTINESS TO NEAR 20 KTS.
LOOKING AHEAD: SHOWERS AND SUB-VFR CONDITIONS WILL OVERSPREAD
CENTRAL NC FROM THE WEST MON NIGHT...AHEAD OF AND ALONG A COLD FRONT
THAT WILL CROSS THE AREA EARLY TUE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...HARTFIELD
SHORT TERM..CBL
LONG TERM...KRR
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS BISMARCK ND
938 PM CDT SUN MAR 10 2013
.DISCUSSION...FORECAST LOOKS TO BE IN GOOD SHAPE THIS EVENING.
ONLY A FEW MINOR ADJUSTMENTS. LOWERED TEMPERATURES A FEW DEGREES
OVER PORTIONS OF THE EAST. BELCOURT WAS AT THE OVERNIGHT LOW LAST
HOUR AND COULD DROP A LITTLE MORE AS THE HIGH CLOUDS ARE JUST
MOVING IN. FARTHER SOUTH IN THE JAMES RIVER BASIN...COULD ALSO SEE
TEMPERATURES DROP SLIGHTLY BELOW FORECAST WITH HIGH PRESSURE
OVERHEAD AND A COUPLE MORE HOURS OF CLEAR SKIES. IN THE
WEST...LIGHT REFLECTIVITIES ARE SHOWING UP IN EASTERN MONTANA. RAP
AND HRRR BRING SOME THESE INTO THE SOUTHWEST SO EXTENDED SLIGHT
CHANCE POPS FARTHER SOUTH INTO THE FAR SOUTHWEST CORNER. DID
REMOVE THE MENTION OF BLOWING SNOW IN THE SOUTHWEST DURING THE
MORNING MONDAY AS WINDS DO NOT REALLY PICK UP UNTIL AFTER ANY
LIGHT SNOW MOVES THROUGH.
&&
.AVIATION...VFR CONDITIONS EXPECTED ACROSS WESTERN AND CENTRAL
NORTH DAKOTA THIS EVENING WITH A LIGHT SOUTHERLY FLOW. WINDS WILL
SHIFT NORTHWEST AT KISN AND KDIK LATE TONIGHT. WINDS TURN
NORTHWEST OVER CENTRAL NORTH DAKOTA ON MONDAY AND FLOW INCREASES
TO GENERALLY 15 TO 25 KNOTS. OCCASIONAL MVFR CEILINGS POSSIBLE IN
A BAND OF LIGHT SNOW ALONG THE COLD FRONT...THEN MORE WIDESPREAD
MVFR CONDITIONS BY MID TO LATE AFTERNOON AS NORTHWEST FLOW BRINGS
LOWER MVFR CEILINGS OVER SOUTHERN CANADA SOUTH ACROSS THE LOCAL
AREA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
TWH
AREA FORECAST DISCUSSION...UPDATED
NWS GRAND FORKS ND
916 PM CDT SUN MAR 10 2013
.DISCUSSION...
TEMPERATURES WILL BE THE MAIN CHALLENGE. PREVIOUS FORECAST
THINKING ON TRACK. CURRENT TEMPERATURES ARE A BIT COOLER THAN
EXPECTED...AND FOLLOWING THE 00Z RAP WILL LOWER MIN TEMPS A BIT.
&&
.AVIATION...
DRIER AIR WILL FILTER INTO AREA...KEEPING CLEAR SKIES FOR ALL
SITES THROUGH THE OVERNIGHT. MID LEVEL DECK WILL ADVECT INTO DVL
LAKE AREA BY EARLY MORNING AND MAY MAKE THE RRV AROUND NOON. MVFR
CIGS ARE POSSIBLE BY LATE AFTERNOON INTO EASTERN NORTH DAKOTA.
&&
.PREV DISCUSSION... /ISSUED 315 PM CDT SUN MAR 10 2013/
SHORT TERM...
HIGH PRESSURE CENTER NEAR BRANDON MANITOBA WILL DRIFT SOUTHEAST
TONIGHT. THE REMAINING CLOUDS IN WEST CENTRAL MN INTO FAR SE ND
WILL CLEAR OUT THIS LATE AFTN-EARLY EVE AND EXPECTING A FAIRLY
CLEAR SKY FOR MOST AREAS TONIGHT. THOUGH DO EXPECT AN INCREASE IN
CLOUDS AFTER MIDNIGHT IN HE DVL REGION FROM THE WEST. RESULT WILL
BE A FAST DROP IN TEMPS THIS EVE IN DVL REGION INTO THE ZERO TO 5
ABOVE RANGE...THEN A BIT OF A RISE LATER TONIGHT. FOR THE RED
RIVER VALLEY/SE ND INTO MINNESOTA LOWS WILL BE CLOSER TO 12Z AND
DO EXPECT ZERO TO 5 ABOVE AS WELL WITH SOME NEGATIVE SINGLE DIGITS
AS WELL IN SOME AREAS. BEST CHC NW MN. WINDS WILL DIMINISH THIS EVE.
MONDAY WILL SEE 500 MB SHORT WAVE TROUG DIG FROM NRN ALBERTA INTO
MANITOBA AND NORTH DAKOTA BY LATE MON AFTN AND THEN INTO
MINNESOTA TUESDAY. SOME LIGHT SNOW ASSOC WITH THIS UPPER WAVE WILL
MOVE THROUGH. MOISTURE IS MOSTLY MID LEVEL BASED FOR PRECIP AND
THERE IS LITTLE SFC LOW REFLECTION. THUS SNOW AMOUNTS PRETTY
MEAGER WITH THIS FEATURE BUT GENERALLY A FEW TENTHS OF AN INCH
WILL FALL. WENT CHC CATEGORY FOR POPS BUT MAY BE A HIGH POP LOW
QPF EVENT ONCE ALL IS DONE.
NEXT HIGH BUILDS IN TUESDAY NIGHT WITH CLEARING AND ANOTHER NIGHT
IN THE LOWER SINGLE DIGITS. THEN A WEAK SHORT WAVE WILL MOVE
THROUGH SRN CANADA WED AFTN-EVE GIVING A LOW CHC OF PRECIP. ECMWF
WHICH HAD BEEN MORE BULLISH ON PREV RUNS IS PRETTY LACKLUSTER ON
ITS 12Z MODEL RUN AND IS LIKE THE REST OF THE MODELS IN HAVING
VERY LITTLE PRECIP.
LONG TERM... /WED NIGHT THROUGH SUN/
MODELS IN DECENT AGREEMENT WITH A WEAK UPPER WAVE MOVING ACROSS
NORTHERN TIER NEAR THE END OF THE WORK WEEK...WHICH WILL BRING A
CHANCE OF SNOW TO THE AREA. TEMPS WILL BE IN MID 30S SO A WINTRY MIX
WOULD BE POSSIBLE IN THE SOUTHERN ZONES...BUT WILL KEEP PREDOMINANT
TYPE SNOW THIS FAR OUT. IN GENERAL THE GFS IS THE MORE BULLISH WITH
MOISTURE. TEMPS FOR THE MOST PART WILL BE IN THE 30S DURING THE
DAYTIME FROM THURSDAY THROUGH THE WEEKEND...WITH OVERNIGHT LOWS
RANGING FROM THE UPPER TEENS TO THE MID 20S.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
856 AM CST SAT MAR 9 2013
.DISCUSSION...LATEST WATER VAPOR IMAGERY SHOWS THE NORTHERN STREAM
TROUGH NOW WORKING THROUGH NORTHWEST NORTH DAKOTA...WHILE THE
SOUTHERN STREAM UPPER LOW IS CIRCULATING OVER NORTHWEST NEW
MEXICO. RADAR IMAGERY AND LATEST RAP MODEL INDICATE LIGHT SNOW
ASSOCIATED WITH THE NORTHERN STREAM TROUGH WILL CONTINUE THROUGH
THE MORNING IN NORTH CENTRAL NORTH DAKOTA AND WANE THIS AFTERNOON
AS THE BEST LIFT SHUTS DOWN AND EXITS TO THE EAST. HAVE BUMPED
POPS TO CATEGORICAL FOR THE REST OF THE MORNING IN MOST OF THE
NORTH CENTRAL BASED ON RADAR AND SURFACE OBS. ALL INDICATIONS
ARE THAT THE NEXT AREA OF PRECIPITATION ASSOCIATED WITH THE
SOUTHERN STREAM LOW NOW IN SOUTH CENTRAL/SOUTHEAST SOUTH DAKOTA
WILL GET SHUNTED EAST AND REMAIN EAST OF OUR FORECAST AREA. WILL
CONTINUE TO ADVERTISE SLIGHT CHC POPS FOR SOME WAFFLING FURTHER
WEST BASED ON THE 06Z RUN OF THE GFS/ECMWF.
FOG WILL CONTINUE THROUGH THE MORNING WITH ISOLATED DENSE FOG
OVER THE NEXT HOUR OR TWO. NO OTHER CHANGES WERE MADE TO THE
CURRENT FORECAST.
&&
.AVIATION...WIDESPREAD FOG AND IFR CIGS AND IFR/MVFR VSBYS WILL
PREVAIL THROUGH MUCH OF THE MORNING WITH IMPROVING CONDITIONS
DURING THE EARLY AFTERNOON. EXPECT PERIODS OF LIGHT SNOW...MAINLY
AT KMOT THROUGH MID AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...KS
AVIATION...KS/LTH
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1142 AM MST SAT MAR 9 2013
.UPDATE...
ISSUED AT 1137 AM MST SAT MAR 9 2013
CALLS TO SPOTTERS INDICATE 2 TO 5 INCHES OF SNOW HAS FALLEN ON
PORTIONS OF SOUTH CENTRAL SD...MAINLY FROM SPRING CREEK TO FAR
NORTHWEST TRIPP COUNTY. A BAND OF HEAVY SNOW...LOOKING CONVECTIVE
AT TIMES ON RADAR/SATELLITE...HAS DEVELOPED IN NORTH CENTRAL
NEBRASKA...MOVING INTO SOUTH CENTRAL SD. LATEST RAP MODEL INDICATES
BAND WILL PERSIST FOR SEVERAL MORE HOURS WITH SNOWFALL RATES UP TO
1 INCH PER HOUR. STORM TOTAL SNOW WILL BE 4 TO 9 INCHES...SO HAVE
UPGRADE TO A WARNING FOR TODD...MELLETTE...AND TRIPP COUNTIES.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 303 AM MST SAT MAR 9 2013
SW CONUS UPPER TROUGH CONTINUES TO PUSH ENE TOWARD THE
REGION AS A NORTHERN STREAM TROUGH DROPS SE INTO THE DAKOTAS. VERY
STRONG WAA RESPONSE ONGOING ACROSS THE CENTRAL PLAINS WILL SPREAD
NORTH INTO SOUTH DAKOTA AND CONTINUE TO SUPPORT RAIN/ZR/AND EVEN A
PERIOD OF TS CHANCES THIS MORNING GIVEN STEEP MID LEVEL LAPSE RATES
AND A CONDITIONALLY UNSTABLE LAYER ALOFT. WAA WILL EVENTUALLY
SUPPORT THE DEVELOPMENT OF A PRONOUNCED DEFORMATION ZONE ACROSS
SCENTRAL SD...WITH VIGOROUS DEEP LAYER ASCENT AS THE NORTHERN STREAM
TROUGH DROPS SOUTH AND SUPPORTS DEEP LAYER CAA. A PERIOD OF HEAVY
SNOW CAN BE EXPECTED IN THE DEFORMATION BAND...WITH HIGH LIQUID
WATER CONTENT AND LOW RATIO. THE LOCATION OF THIS SNOW BAND REMAINS
SEMI-ELUSIVE GIVEN THE PRESENCE OF A STRONG WARM NOSE...AND FORECAST
MODELS HAVE WAVERED PER ITS PLACEMENT. HOWEVER...LATEST GUIDANCE
/ESP FROM THE NAM/ HAVE HONED THE LOCATION TO EASTERN TODD/MELLETTE
AND MUCH OF TRIPP COUNTY. OTHERWISE...THE REMAINDER OF THE FA LOOKS
TO BE FAIRLY DRY SAVE PERHAPS A LITTLE LIGHT SNOW OVER THE NORTHERN
HILLS WHICH LOOKS IFFY AT THIS POINT GIVEN A SHARPLY DRYING BL.
SUBSIDING FLOW WILL PREVAIL ON SUNDAY...WITH DEEP LAYER RIDGING AND
DRY CONDITIONS.
ROBUST WAA RESPONSE WILL PUSH NORTH IN SCENTRAL SD THIS
MORNING...SUPPORTING RAIN/FREEZING RAIN/AND SNOW. RAIN AND FREEZING
RAIN IS EXPECTED TO LAST THROUGH MID MORNING OVER PORTIONS OF
MELLETTE/TODD/AND TRIPP COUNTIES WHERE SOME LIGHT ICING UP TO ONE
TENTH OF A INCH WILL BE POSSIBLE UNTIL ALL PRECIP TRANSITIONS TO
SNOW. MAIN LOBE OF DEEP LAYER ASCENT WILL SPREAD INTO SCENTRAL SD
MID TO LATE MORNING...WITH A STRENGTHENING LL DEFORMATION ZONE.
STRONG LIFT CENTERED IN THE SNOW GROWTH ZONE WILL SUPPORT A VERY
INTENSE BAND OF HEAVY SNOW FOR 3-6 HOURS. HEAVY SNOWFALL RATES ARE
EXPECTED WITH LOCATIONS IN THE BAND EXPECTED TO SEE 3-5 INCHES.
LOCALLY HIGHER AMOUNTS WILL BE POSSIBLE BEFORE SNOW TAPERS OFF THIS
EVENING. A SHARP CUT OFF IN PRECIP IS EXPECTED...SUPPORTING MAINLY
DRY CONDITIONS ACROSS THE NW 1/2-2/3. HAVE DROPPED THE WINTER WEATHER
ADV FOR THE TWO NW COUNTIES...GIVEN LACK OF SIG PRECIP. STRONG
PRESSURE RISES WILL ENSUE IN A CAA REGIME SUPPORTING GUSTY NW
WINDS. STRONGEST WINDS WILL BE IN THE LEE OF THE BH AND ADJACENT
PLAINS GIVEN FLOW ENHANCEMENT AROUND THE BH. SUSTAINED WINDS OF 25 TO
30 MPH WITH GUSTS TO AROUND 50 MPH ARE EXPECTED. HAVE ISSUED A WIND
ADV FOR THIS. 15 TO 30 MPH WINDS WILL SPREAD INTO SCNTRL SD THIS
AFTERNOON AND EVENING AND MAY SUPPORT AREAS OF BLOWING SNOW
DEPENDING ON BL TEMPS. MANY FORECAST SOLUTIONS OFFER TEMPS IN LOWER
30S BY AFTERNOON WHICH COULD HAMPER SNOW LIFTING POTENTIAL THERE.
ADJUSTED POPS TO FIT ABOVE CONCERNS...WITH SOME ADJUSTMENT TO TEMPS.
SUNDAY...FAIRLY QUIET WEATHER TO PREVAIL WITH A PERIOD OF SHORTWAVE
RIDGING. WAA EXPECTED TO INFLUENCE TEMPS ACROSS THE WESTERN HALF OF
THE FA...WITH EASTERN AREAS LIKELY REMAINING UNDER A SUBSIDENCE
INVERSION AND CONTINUED NORTHERLY FLOW. SNOW COVER WILL ALSO
INFLUENCE TEMPS OVER SCENTRAL AREAS. LOWS WILL BE TRICKY SUNDAY
NIGHT OVER THE SNOW PACK...WHERE SIG T DROP OFFS ARE POSSIBLE GIVEN
CLEAR SKIES AND LIGHT WINDS.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 303 AM MST SAT MAR 9 2013
RIDGE BUILDS OVER THE WESTERN CONUS...WITH AXIS SLOWLY SHIFTING
TOWARDS THE PLAINS THROUGH THE EXTENDED. THIS WILL BRING MILD TEMPS
THROUGH MID-WEEK...WITH WARMER TEMPS EXPECTED FOR THE LAST PART OF
THE WORK WEEK. OCCASIONAL WEAK DISTURBANCES MOVING THROUGH MAY BRING
A FEW LIGHT SHOWERS THROUGH MID-WEEK...WITH GENERALLY DRY CONDITIONS
FOR THE END OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1035 AM MST SAT MAR 9 2013
CONDITIONS IMPROVING OVER NE WY AND EXTRM WRN SD WITH CIGS AND
VSBYS QUICKLY BECOMING VFR EXCEPT SOME LOW CLOUDS PERSISTING OVER
THE BLACK HILLS. ELSEWHERE...OVER S CNTRL SD WIDESPREAD IFR AND
LIFR CIGS AND VSBYS IN SNOW WILL CONTINUE INTO MID AFTN BEFORE
GRADUALLY IMPROVING FROM NW TO SE AS SNOW MOVES OUT OF THE AREA.
LOW CLOUDS WILL PERSIST UNTIL NEAR SUNSET OVER S CNTRL SD. NORTH AND
NORTHWESTERLY WINDS OF 25-30 KTS WITH GUSTS UP TO 40KTS WILL COVER
MOST OF THE FCST AREA...WITH STRONGEST WINDS JUST EAST OF THE
BLACK HILLS BEFORE GRADUALLY DIMINISHING AFTER SUNSET. PATCHY LOW
STRATUS IS LIKELY TO REDEVELOP OVER NE WY AND WRN PORTIONS OF SD
AROUND 06Z TONIGHT.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 PM MST THIS EVENING FOR SDZ044.
WINTER STORM WARNING UNTIL 7 PM CST THIS EVENING FOR SDZ046-047-
049.
WIND ADVISORY UNTIL 7 PM MST THIS EVENING FOR SDZ026-030-031-
072>074.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...77
AVIATION...BARBER
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1038 AM MST SAT MAR 9 2013
.UPDATE...
ISSUED AT 855 AM MST SAT MAR 9 2013
15Z SURFACE ANALYSIS HAD LOW OVER SOUTHEAST CO WITH NEARLY
STATIONARY BOUNDARY INTO EASTERN ND. FIRST IMPULSE FROM STORM
SYSTEM BROUGHT A BRIEF PERIOD OF -FZRA TO SOUTH CENTRAL SD...BUT
CALLS TO SPOTTERS INDICATE CHANGEOVER TO SN HAS OCCURRED WITH 1-2
INCHES IN THE LAST COUPLE OF HOURS. 12Z RAP HAD A GOOD HANDLE ON
CURRENT SENSIBLE WEATHER. NARROW BAND OF -SN/SN WILL CONTINUE
THROUGH THIS AFTERNOON OVER SOUTH CENTRAL SD AS MAIN IMPULSE MOVES
NORTHEAST INTO THE CENTRAL PLAINS. SNOW COINCIDENT WITH STRONG
BAND OF 850-700MB FRONTOGENESIS...NORTHERN EDGE OF 700-500MB QG-
FORCING...AND UNDER LEFT EXIT REGION OF 90KT JET STREAK RACING UP
FRONT SIDE OF UPPER TROUGH OVER CO/NM. NORTHERN STREAM TROUGH WILL
RACE SOUTHEAST...BRINGING MUCH DRIER AIR INTO CWA...AND THUS...AN
END TO LINGERING -SN OVER NORTHWEST 2/3RDS OF CWA. 25-30KT 850MB
WINDS WILL MIX OVER NORTHWEST SD LEADING TO WINDY CONDITIONS AS IN
CURRENT FORECAST. UPDATE OUT SHORTLY.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 303 AM MST SAT MAR 9 2013
SW CONUS UPPER TROUGH CONTINUES TO PUSH ENE TOWARD THE
REGION AS A NORTHERN STREAM TROUGH DROPS SE INTO THE DAKOTAS. VERY
STRONG WAA RESPONSE ONGOING ACROSS THE CENTRAL PLAINS WILL SPREAD
NORTH INTO SOUTH DAKOTA AND CONTINUE TO SUPPORT RAIN/ZR/AND EVEN A
PERIOD OF TS CHANCES THIS MORNING GIVEN STEEP MID LEVEL LAPSE RATES
AND A CONDITIONALLY UNSTABLE LAYER ALOFT. WAA WILL EVENTUALLY
SUPPORT THE DEVELOPMENT OF A PRONOUNCED DEFORMATION ZONE ACROSS
SCENTRAL SD...WITH VIGOROUS DEEP LAYER ASCENT AS THE NORTHERN STREAM
TROUGH DROPS SOUTH AND SUPPORTS DEEP LAYER CAA. A PERIOD OF HEAVY
SNOW CAN BE EXPECTED IN THE DEFORMATION BAND...WITH HIGH LIQUID
WATER CONTENT AND LOW RATIO. THE LOCATION OF THIS SNOW BAND REMAINS
SEMI-ELUSIVE GIVEN THE PRESENCE OF A STRONG WARM NOSE...AND FORECAST
MODELS HAVE WAVERED PER ITS PLACEMENT. HOWEVER...LATEST GUIDANCE
/ESP FROM THE NAM/ HAVE HONED THE LOCATION TO EASTERN TODD/MELLETTE
AND MUCH OF TRIPP COUNTY. OTHERWISE...THE REMAINDER OF THE FA LOOKS
TO BE FAIRLY DRY SAVE PERHAPS A LITTLE LIGHT SNOW OVER THE NORTHERN
HILLS WHICH LOOKS IFFY AT THIS POINT GIVEN A SHARPLY DRYING BL.
SUBSIDING FLOW WILL PREVAIL ON SUNDAY...WITH DEEP LAYER RIDGING AND
DRY CONDITIONS.
ROBUST WAA RESPONSE WILL PUSH NORTH IN SCENTRAL SD THIS
MORNING...SUPPORTING RAIN/FREEZING RAIN/AND SNOW. RAIN AND FREEZING
RAIN IS EXPECTED TO LAST THROUGH MID MORNING OVER PORTIONS OF
MELLETTE/TODD/AND TRIPP COUNTIES WHERE SOME LIGHT ICING UP TO ONE
TENTH OF A INCH WILL BE POSSIBLE UNTIL ALL PRECIP TRANSITIONS TO
SNOW. MAIN LOBE OF DEEP LAYER ASCENT WILL SPREAD INTO SCENTRAL SD
MID TO LATE MORNING...WITH A STRENGTHENING LL DEFORMATION ZONE.
STRONG LIFT CENTERED IN THE SNOW GROWTH ZONE WILL SUPPORT A VERY
INTENSE BAND OF HEAVY SNOW FOR 3-6 HOURS. HEAVY SNOWFALL RATES ARE
EXPECTED WITH LOCATIONS IN THE BAND EXPECTED TO SEE 3-5 INCHES.
LOCALLY HIGHER AMOUNTS WILL BE POSSIBLE BEFORE SNOW TAPERS OFF THIS
EVENING. A SHARP CUT OFF IN PRECIP IS EXPECTED...SUPPORTING MAINLY
DRY CONDITIONS ACROSS THE NW 1/2-2/3. HAVE DROPPED THE WINTER WEATHER
ADV FOR THE TWO NW COUNTIES...GIVEN LACK OF SIG PRECIP. STRONG
PRESSURE RISES WILL ENSUE IN A CAA REGIME SUPPORTING GUSTY NW
WINDS. STRONGEST WINDS WILL BE IN THE LEE OF THE BH AND ADJACENT
PLAINS GIVEN FLOW ENHANCEMENT AROUND THE BH. SUSTAINED WINDS OF 25 TO
30 MPH WITH GUSTS TO AROUND 50 MPH ARE EXPECTED. HAVE ISSUED A WIND
ADV FOR THIS. 15 TO 30 MPH WINDS WILL SPREAD INTO SCNTRL SD THIS
AFTERNOON AND EVENING AND MAY SUPPORT AREAS OF BLOWING SNOW
DEPENDING ON BL TEMPS. MANY FORECAST SOLUTIONS OFFER TEMPS IN LOWER
30S BY AFTERNOON WHICH COULD HAMPER SNOW LIFTING POTENTIAL THERE.
ADJUSTED POPS TO FIT ABOVE CONCERNS...WITH SOME ADJUSTMENT TO TEMPS.
SUNDAY...FAIRLY QUIET WEATHER TO PREVAIL WITH A PERIOD OF SHORTWAVE
RIDGING. WAA EXPECTED TO INFLUENCE TEMPS ACROSS THE WESTERN HALF OF
THE FA...WITH EASTERN AREAS LIKELY REMAINING UNDER A SUBSIDENCE
INVERSION AND CONTINUED NORTHERLY FLOW. SNOW COVER WILL ALSO
INFLUENCE TEMPS OVER SCENTRAL AREAS. LOWS WILL BE TRICKY SUNDAY
NIGHT OVER THE SNOW PACK...WHERE SIG T DROP OFFS ARE POSSIBLE GIVEN
CLEAR SKIES AND LIGHT WINDS.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 303 AM MST SAT MAR 9 2013
RIDGE BUILDS OVER THE WESTERN CONUS...WITH AXIS SLOWLY SHIFTING
TOWARDS THE PLAINS THROUGH THE EXTENDED. THIS WILL BRING MILD TEMPS
THROUGH MID-WEEK...WITH WARMER TEMPS EXPECTED FOR THE LAST PART OF
THE WORK WEEK. OCCASIONAL WEAK DISTURBANCES MOVING THROUGH MAY BRING
A FEW LIGHT SHOWERS THROUGH MID-WEEK...WITH GENERALLY DRY CONDITIONS
FOR THE END OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1035 AM MST SAT MAR 9 2013
CONDITIONS IMPROVING OVER NE WY AND EXTRM WRN SD WITH CIGS AND
VSBYS QUICKLY BECOMING VFR EXCEPT SOME LOW CLOUDS PERSISTING OVER
THE BLACK HILLS. ELSEWHERE...OVER S CNTRL SD WIDESPREAD IFR AND
LIFR CIGS AND VSBYS IN SNOW WILL CONTINUE INTO MID AFTN BEFORE
GRADUALLY IMPROVING FROM NW TO SE AS SNOW MOVES OUT OF THE AREA.
LOW CLOUDS WILL PERSIST UNTIL NEAR SUNSET OVER S CNTRL SD. NORTH AND
NORTHWESTERLY WINDS OF 25-30 KTS WITH GUSTS UP TO 40KTS WILL COVER
MOST OF THE FCST AREA...WITH STRONGEST WINDS JUST EAST OF THE
BLACK HILLS BEFORE GRADUALLY DIMINISHING AFTER SUNSET. PATCHY LOW
STRATUS IS LIKELY TO REDEVELOP OVER NE WY AND WRN PORTIONS OF SD
AROUND 06Z TONIGHT.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 5 PM MST /6 PM CST/ THIS AFTERNOON
FOR SDZ044-046-047-049.
WIND ADVISORY UNTIL 7 PM MST THIS EVENING FOR SDZ026-030-031-
072>074.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...77
AVIATION...BARBER
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
855 AM MST SAT MAR 9 2013
.UPDATE...
ISSUED AT 855 AM MST SAT MAR 9 2013
15Z SURFACE ANALYSIS HAD LOW OVER SOUTHEAST CO WITH NEARLY
STATIONARY BOUNDARY INTO EASTERN ND. FIRST IMPULSE FROM STORM
SYSTEM BROUGHT A BRIEF PERIOD OF -FZRA TO SOUTH CENTRAL SD...BUT
CALLS TO SPOTTERS INDICATE CHANGEOVER TO SN HAS OCCURRED WITH 1-2
INCHES IN THE LAST COUPLE OF HOURS. 12Z RAP HAD A GOOD HANDLE ON
CURRENT SENSIBLE WEATHER. NARROW BAND OF -SN/SN WILL CONTINUE
THROUGH THIS AFTERNOON OVER SOUTH CENTRAL SD AS MAIN IMPULSE MOVES
NORTHEAST INTO THE CENTRAL PLAINS. SNOW COINCIDENT WITH STRONG
BAND OF 850-700MB FRONTOGENESIS...NORTHERN EDGE OF 700-500MB QG-
FORCING...AND UNDER LEFT EXIT REGION OF 90KT JET STREAK RACING UP
FRONT SIDE OF UPPER TROUGH OVER CO/NM. NORTHERN STREAM TROUGH WILL
RACE SOUTHEAST...BRINGING MUCH DRIER AIR INTO CWA...AND THUS...AN
END TO LINGERING -SN OVER NORTHWEST 2/3RDS OF CWA. 25-30KT 850MB
WINDS WILL MIX OVER NORTHWEST SD LEADING TO WINDY CONDITIONS AS IN
CURRENT FORECAST. UPDATE OUT SHORTLY.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 303 AM MST SAT MAR 9 2013
SW CONUS UPPER TROUGH CONTINUES TO PUSH ENE TOWARD THE
REGION AS A NORTHERN STREAM TROUGH DROPS SE INTO THE DAKOTAS. VERY
STRONG WAA RESPONSE ONGOING ACROSS THE CENTRAL PLAINS WILL SPREAD
NORTH INTO SOUTH DAKOTA AND CONTINUE TO SUPPORT RAIN/ZR/AND EVEN A
PERIOD OF TS CHANCES THIS MORNING GIVEN STEEP MID LEVEL LAPSE RATES
AND A CONDITIONALLY UNSTABLE LAYER ALOFT. WAA WILL EVENTUALLY
SUPPORT THE DEVELOPMENT OF A PRONOUNCED DEFORMATION ZONE ACROSS
SCENTRAL SD...WITH VIGOROUS DEEP LAYER ASCENT AS THE NORTHERN STREAM
TROUGH DROPS SOUTH AND SUPPORTS DEEP LAYER CAA. A PERIOD OF HEAVY
SNOW CAN BE EXPECTED IN THE DEFORMATION BAND...WITH HIGH LIQUID
WATER CONTENT AND LOW RATIO. THE LOCATION OF THIS SNOW BAND REMAINS
SEMI-ELUSIVE GIVEN THE PRESENCE OF A STRONG WARM NOSE...AND FORECAST
MODELS HAVE WAVERED PER ITS PLACEMENT. HOWEVER...LATEST GUIDANCE
/ESP FROM THE NAM/ HAVE HONED THE LOCATION TO EASTERN TODD/MELLETTE
AND MUCH OF TRIPP COUNTY. OTHERWISE...THE REMAINDER OF THE FA LOOKS
TO BE FAIRLY DRY SAVE PERHAPS A LITTLE LIGHT SNOW OVER THE NORTHERN
HILLS WHICH LOOKS IFFY AT THIS POINT GIVEN A SHARPLY DRYING BL.
SUBSIDING FLOW WILL PREVAIL ON SUNDAY...WITH DEEP LAYER RIDGING AND
DRY CONDITIONS.
ROBUST WAA RESPONSE WILL PUSH NORTH IN SCENTRAL SD THIS
MORNING...SUPPORTING RAIN/FREEZING RAIN/AND SNOW. RAIN AND FREEZING
RAIN IS EXPECTED TO LAST THROUGH MID MORNING OVER PORTIONS OF
MELLETTE/TODD/AND TRIPP COUNTIES WHERE SOME LIGHT ICING UP TO ONE
TENTH OF A INCH WILL BE POSSIBLE UNTIL ALL PRECIP TRANSITIONS TO
SNOW. MAIN LOBE OF DEEP LAYER ASCENT WILL SPREAD INTO SCENTRAL SD
MID TO LATE MORNING...WITH A STRENGTHENING LL DEFORMATION ZONE.
STRONG LIFT CENTERED IN THE SNOW GROWTH ZONE WILL SUPPORT A VERY
INTENSE BAND OF HEAVY SNOW FOR 3-6 HOURS. HEAVY SNOWFALL RATES ARE
EXPECTED WITH LOCATIONS IN THE BAND EXPECTED TO SEE 3-5 INCHES.
LOCALLY HIGHER AMOUNTS WILL BE POSSIBLE BEFORE SNOW TAPERS OFF THIS
EVENING. A SHARP CUT OFF IN PRECIP IS EXPECTED...SUPPORTING MAINLY
DRY CONDITIONS ACROSS THE NW 1/2-2/3. HAVE DROPPED THE WINTER WEATHER
ADV FOR THE TWO NW COUNTIES...GIVEN LACK OF SIG PRECIP. STRONG
PRESSURE RISES WILL ENSUE IN A CAA REGIME SUPPORTING GUSTY NW
WINDS. STRONGEST WINDS WILL BE IN THE LEE OF THE BH AND ADJACENT
PLAINS GIVEN FLOW ENHANCEMENT AROUND THE BH. SUSTAINED WINDS OF 25 TO
30 MPH WITH GUSTS TO AROUND 50 MPH ARE EXPECTED. HAVE ISSUED A WIND
ADV FOR THIS. 15 TO 30 MPH WINDS WILL SPREAD INTO SCNTRL SD THIS
AFTERNOON AND EVENING AND MAY SUPPORT AREAS OF BLOWING SNOW
DEPENDING ON BL TEMPS. MANY FORECAST SOLUTIONS OFFER TEMPS IN LOWER
30S BY AFTERNOON WHICH COULD HAMPER SNOW LIFTING POTENTIAL THERE.
ADJUSTED POPS TO FIT ABOVE CONCERNS...WITH SOME ADJUSTMENT TO TEMPS.
SUNDAY...FAIRLY QUIET WEATHER TO PREVAIL WITH A PERIOD OF SHORTWAVE
RIDGING. WAA EXPECTED TO INFLUENCE TEMPS ACROSS THE WESTERN HALF OF
THE FA...WITH EASTERN AREAS LIKELY REMAINING UNDER A SUBSIDENCE
INVERSION AND CONTINUED NORTHERLY FLOW. SNOW COVER WILL ALSO
INFLUENCE TEMPS OVER SCENTRAL AREAS. LOWS WILL BE TRICKY SUNDAY
NIGHT OVER THE SNOW PACK...WHERE SIG T DROP OFFS ARE POSSIBLE GIVEN
CLEAR SKIES AND LIGHT WINDS.
.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 303 AM MST SAT MAR 9 2013
RIDGE BUILDS OVER THE WESTERN CONUS...WITH AXIS SLOWLY SHIFTING
TOWARDS THE PLAINS THROUGH THE EXTENDED. THIS WILL BRING MILD TEMPS
THROUGH MID-WEEK...WITH WARMER TEMPS EXPECTED FOR THE LAST PART OF
THE WORK WEEK. OCCASIONAL WEAK DISTURBANCES MOVING THROUGH MAY BRING
A FEW LIGHT SHOWERS THROUGH MID-WEEK...WITH GENERALLY DRY CONDITIONS
FOR THE END OF THE WORK WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 303 AM MST SAT MAR 9 2013
WIDESPREAD IFR CONDITIONS WILL CONT THRU WRN SD INTO PTNS OF NERN WY
THROUGH MUCH OF THE DAY. OVER S CNTRL SD FZRA/SN EXPECTED THIS
MORN...WITH A TRANSITION TO ALL SN THIS AFTERNOON. ELSEWHERE...
PERIODS OF SNOW ARE EXPECTED WITH THE GREATEST CHANCES TOWARDS THE
NEBRASKA BORDER. PRECIP WILL DIMINISH FROM NORTHWEST TO SOUTHEAST
LATER THIS AFTERNOON INTO THIS EVE WITH CIGS/VIS IMPROVING.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 5 PM MST /6 PM CST/ THIS AFTERNOON
FOR SDZ044-046-047-049.
WIND ADVISORY UNTIL 7 PM MST THIS EVENING FOR SDZ026-030-031-
072>074.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...77
AVIATION...77
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1036 PM CST FRI MAR 8 2013
.DISCUSSION.../ISSUED AT 1010 PM CST/
PRECIPITATION BEGINNING TO EXPAND ACROSS THE AREA WITHS STRONG MID
LEVEL WARM AIR ADVECTION. TEMPERATURES ACROSS THE CWA HAVE GENERALLY
RISEN ABOVE FREEZING AT THIS POINT. THE RAP SEEMS TO HAVE THE
BEST HANDLE ON THE CURRENT SURFACE TEMPERATURES...AND IT SUGGESTS
MOST OF OUR NORTH STAYS JUST ABOVE FREEZING THROUGH THE NIGHT. THUS
THINKING MAINLY PLAIN RAIN...ALTHOUGH SOME ICY SPOTS ARE STILL
POSSIBLE ALONG THE HIGHWAY 14 CORRIDOR WHERE TEMPERATURES WILL FLIRT
WITH THE FREEZING MARK TROUGH THE NIGHT. STARTING TO SEE SOME
THUNDER ACROSS NORTHEAST NEBRASKA...AND WITH ELEVATED INSTABILITY
MOVING INTO OUR AREA...THINK A FEW LIGHTNING STRIKES WILL BE
POSSIBLE...MAINLY ALONG AND SOUTH OF INTERSTATE 90.
MODELS COMING INTO BETTER AGREEMENT ON EVOLUTION OF THE SYSTEM
TOMORROW...ALTHOUGH UNCERTAINTY STILL EXISTS. NAM...GFS AND SREF ALL
SHOWING WHAT COULD BE AN INTENSE MID LEVEL FRONT WEST OF THE JAMES
RIVER WITH SOME ELEVATED INSTABILITY AS WELL. THUS THOUGHT IS WE
COULD SEE A NARROW INTENSE BAND OF SNOW SOMEWHERE OUT THERE...BEST
GUESS AT THIS POINT FROM AROUND GREGORY COUNTY TO BEADLE. AS THE
NORTHERN STREAM WAVE PUSHES SOUTHEAST EXPECT DRY AIR AND INCREASING
SUBSIDENCE TO ENCROACH FROM THE NORTHWEST DURING THE AFTERNOON AND
EVENING. THIS SHOULD ACT TO DISSIPATE THIS BAND AS IT PUSHES OFF
SOUTHEAST. HOWEVER AS THE SOUTHERN STREAM WAVE AND PV ANOMALY EJECT
INTO THE CENTRAL PLAINS...EXPECT THE BAND TO REFORM FROM CENTRAL
NEBRASKA TO NORTHWEST IOWA. THIS WILL ALSO LIKELY BE A SOMEWHAT
NARROW CORRIDOR OF MODERATE TO POTENTIALLY HEAVY SNOW FOR SATURDAY
NIGHT. SO...CURRENT THOUGHTS ARE FOR LIGHT ICING ACROSS OUR FAR
NORTH AND ALSO WEST...GIVING WAY TO 3 TO 6 INCHES OF SNOW WEST OF
THE JAMES RIVER IN THAT INITIAL BAND. COULD EVEN SEE ISOLATED HIGHER
AMOUNTS...AND FUTURE SHIFTS WILL HAVE TO MONITOR NEW MODEL RUNS AND
POSSIBLY CONSIDER UPGRADING A FEW OF THOSE COUNTIES TO WARNINGS.
ANOTHER AREA OF 2 TO 6 INCHES SEEMS PROBABLE FROM YANKTON EAST INTO
NORTHWEST IOWA WITH THE SECOND BAND THAT FORMS. AGAIN ISOLATED
HIGHER AMOUNTS WILL BE POSSIBLE THERE AS WELL. PRETTY CONFIDENT WE
WILL NEED AN ADVISORY IN THAT AREA TOMORROW NIGHT...BUT CONFIDENCE
WAS TOO LOW FOR A WATCH. WINDS WILL PICK UP SATURDAY NIGHT INTO
SUNDAY LIKELY CREATING BLOWING AND DRIFTING ISSUES WITH ANY SNOW
THAT FALLS. SO FUTURE SHIFTS WILL ALSO HAVE TO DECIDE IF SNOW
AMOUNTS WILL BE HIGH ENOUGH...THAT COMBINED WITH THE WINDS...WOULD
WARRANT A WARNING FOR NORTHWEST IOWA. IN BETWEEN THESE TWO
BANDS...GENERALLY EXPECTING AN INCH OR TWO OF SNOW.
IN SUMMARY...MAINLY RAIN TONIGHT...CHANGING TO SNOW FROM NORTHWEST
TO SOUTHEAST TOMORROW INTO TOMORROW EVENING...ROUGHLY AFTER 9 AM
HURON...AFTER 1 PM MITCHELL...AFTER 6 PM SIOUX FALLS AND AFTER 9 PM
SIOUX CITY. EXPECTING TWO BANDS OF POTENTIALLY UP TO 6 INCHES OF
SNOW...ONE WEST OF THE JAMES RIVER AND ONE ACROSS NORTHWEST
IOWA...AND LESS IN BETWEEN. WITH THAT SAID...UNCERTAINTY STILL
EXISTS IN PLACEMENT OF THESE BANDS...AND WILL DEPEND ON STRENGTH OF
BOTH THE NORTHERN AND SOUTHERN STREAM. NEW 0Z GFS AND 0Z GEM HAVE
GONE AGAINST THE 12Z EC...0Z NAM AND 21Z SREF...IN THAT THEY ARE
SLIGHTLY FURTHER NORTH WITH BOTH BANDS...SUGGESTING A BIT MORE SNOW
FOR SIOUX FALLS. THUS STILL A FLUID SITUATION THAT WILL HAVE TO BE
MONITORED CLOSELY TONIGHT AND TOMORROW. CURRENT FORECAST FAVORS THE
MORE SOUTHERN SREF...NAM AND EC. /CHENARD
.PREVIOUS DISCUSSION.../ISSUED AT 253 PM CST/
QUITE A LOT OF CONVECTION IN THE DESERT SOUTHWEST WITH THE COMPACT
UPPER LEVEL LOW PRESSURE THAT WILL SOON BE AFFECTING OUR PART OF THE
COUNTRY. AS THIS WAVE MOVES INTO THE FOUR CORNERS REGION TONIGHT
SOUTHERLY FLOW WILL INCREASE ACROSS THE PLAINS. WITH DECENT LAPSE
RATES ALOFT AND VERY STRONG THERMAL/MOISTURE ADVECTION IN THE MID
LEVELS SUSPECT RAIN WILL DEVELOP QUICKLY TONIGHT OVER NEBRASKA INTO
SOUTH DAKOTA...IOWA AND MINNESOTA. THE LEAD WAVE CAUSING THIS
PRECIPITATION WILL SWING A DRY SLOT NORTHWARD LATE TONIGHT INTO
TOMORROW MORNING WHICH COULD SHUT DOWN THE SOUTHEAST HALF OF THE CWA
FOR AWHILE ON SATURDAY MORNING AND EARLY AFTERNOON AS SATURATION
ALOFT IS LOST AND TEMPERATURES LOWER ARE NOT COLD ENOUGH. RAINFALL
AMOUNTS TONIGHT IN MANY LOCATIONS LIKELY A QUARTER TO A HALF AN
INCH. WILL GO WITH A WINTER WEATHER ADVISORY FROM CHAMBERLAIN TO
HURON TO MARSHALL STARTING TONIGHT AND CONTINUING THROUGH SATURDAY
AFTERNOON. THE MAIN THREAT WILL BE FREEZING RAIN FROM ABOUT MIDNIGHT
THROUGH SUNRISE SATURDAY MORNING WHERE A TENTH TO TWO TENTHS OF AN
INCH OF ICING WILL BE POSSIBLE. WILL CONTINUE THROUGH THE AFTERNOON
AS SNOW WILL LIKELY DEVELOP...POSSIBLY ACCUMULATING AN INCH OR
TWO...AND WINDS WILL SIGNIFICANTLY INCREASE WITH GUSTS TO ABOUT 40
MPH POSSIBLE. ON TOP OF THE PRECIPITATION TONIGHT THE SOUTHERN HALF
OF THE CWA...MAINLY SOUTH OF INTERSTATE 90...COULD HEAR A LITTLE
THUNDER.
AS THIS POTENT WAVE SWINGS ONTO THE PLAINS SATURDAY DYNAMIC COOLING
WILL BEGIN TO QUICKLY SHIFT COLDER AIR INTO THE MID AND LOW LEVELS
AND TRANSITION THIS COLD AIR FROM WEST TO EAST. FREEZING RAIN WILL
TRANSITION TO SNOW IN THE WEST IN THE MORNING THEN CHANGE TO SNOW
FROM ABOUT MARSHALL TO SIOUX FALLS TO YANKTON AROUND 600 PM...THEN
IN NW IA AROUND 900 PM. THE STRONGEST FORCING LOOKS TO OCCUR FROM
ABOUT 0Z THROUGH 9Z IN THE SOUTHERN THIRD OF THE CWA. RIGHT NOW
THINKING MAINLY 1 TO 3 INCHES OF SNOW MOST LOCATIONS BUT THE BAND
THAT DEVELOPS IN NORTHERN NEBRASKA INTO NORTHWEST IOWA WILL HAVE THE
POTENTIAL TO PRODUCE 6 INCHES OR MORE OF SNOW IN A FAIRLY SHORT
PERIOD OF TIME. WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR
BLOWING SNOW ON SATURDAY NIGHT AND SUNDAY MORNING IF MORE SNOW
OCCURS THAN EXPECTED AS GUSTS TO AROUND 40 TO 45 MPH IS NOT OUT OF
THE QUESTION.
SUSPECT WHAT WILL HAPPEN ON SATURDAY IS THE WARM ADVECTION BAND IN
THE NORTHERN CWA WILL FALL APART RATHER THAN TRANSITION FROM WEST TO
EAST. WHEN THE COLD FRONT ALOFT SWINGS INTO NORTHERN NEBRASKA
SATURDAY AFTERNOON A NEW BAND OF PRECIPITATION WILL DEVELOP AND
BECOME THE DOMINANT FEATURE. TRIED TO GET THIS POINT ACROSS IN THE
GRIDS BUT NOT EASY TO ACCOMPLISH. THIS SECOND BAND WILL BE THE ONE
THAT COULD PRODUCE SOME HEAVY SNOW AND ITS LOCATION WILL BE VERY
IMPORTANT. MOST OF THE SNOWFALL WILL BE EAST OF THE CWA BY 12Z
SUNDAY WITH A COLD AND WINDY SUNDAY EXPECTED.
HIGH PRESSURE RIDGE AXIS SLIDES ACROSS THE REGION ON SUNDAY
NIGHT...BRINGING DYING WINDS AND DECREASING CLOUDS. THIS IN
CONJUNCTION WITH LOW LEVEL COLD AIR ADVECTION WILL RESULT IN A
CHILLY NIGHT WITH LOWS IN THE SINGLE DIGITS AND TEENS.
THE HIGH MOVES EASTWARD ON MONDAY AS A SURFACE TROUGH APPROACHES
FROM THE WEST. THIS WILL PUT MUCH OF OUR AREA IN A RETURNING
SOUTHERLY FLOW...AND TEMPERATURES WILL RESPOND IN LIKE...ESPECIALLY
IN OUR SOUTHWEST...WITH HIGHS INTO THE MID 40S OVER THAT THAT AREA.
BACK TO THE EAST READINGS WILL TAPER DOWN INTO THE 30S...WITH
TEMPERATURES A LITTLE TRICKY DEPENDENT ON WHERE FRESH SNOW COVER IS
IS IN PLACE WITH SAT/SUN STORM. THE SURFACE TROUGH/BOUNDARY BEGINS
TO SLIDE INTO THE WEST LATE IN THE AFTERNOON...THEN SLIDING ACROSS
THE AREA ON MONDAY NIGHT. THE ECMWF/GEM WANTING TO SPIT OUT A LITTLE
PRECIPITATION WITH THIS IN THE LATE AFTERNOON OR EVENING AS AN UPPER
LEVEL SHORTWAVE TRACKS FROM NORTH DAKOTA TO THE LOWER GREAT LAKES
REGION OVERNIGHT. AT THE SAME TIME...THE GFS/NAM KEEP IT DRY AND
DECIDED TO GO THAT WAY WITH MOISTURE LOOKING TO BE PRETTY LIMITED.
IN THE EXTENDED...TUESDAY THROUGH FRIDAY...MODELS IN GOOD AGREEMENT
ON KEEPING OUR AREA IN A NORTHWESTERLY UPPER LEVEL FLOW THROUGH THE
THE PERIOD. HOWEVER...MODELS ARE IN LESS IN AGREEMENT ON THE
MESOSCALE FEATURES...WITH LOOSE CONSENSUS ON POSSIBLE PRECIPITATION
SOMETIME IN THE WEDNESDAY AND FRIDAY TIME FRAME AND KEPT SMALL
CHANCE POPS IN FOR THOSE PERIODS. TEMPERATURES THROUGH THE EXTENDED
LOOK TO REMAIN AT OR ABOVE NORMALS FOR THIS TIME OF YEAR.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
MVFR CEILINGS WILL CONTINUE TO EXPAND ACROSS THE CWA TONIGHT AND
WILL BECOME IFR ACROSS THE ENTIRE AREA BY 12Z SATURDAY. WIDESPREAD
RAIN IS ALSO EXPECTED OVERNIGHT MIXING WITH FREEZING RAIN AND
CHANGING TO SNOW WEST OF INTERSTATE 29 DURING THE DAY ON SATURDAY
AND EAST OF INTERSTATE 29 AFTER 00Z SUNDAY. VISIBILITIES WILL DROP
BELOW ONE MILE AT TIMES...ESPECIALLY IN THE SNOW ON SATURDAY. GUSTY
NORTH WINDS OF 20 TO 30 KNOTS WILL DEVELOP WEST OF INTERSTATE 29 BY
SATURDAY AFTERNOON AND PERSIST THROUGH 06Z SUNDAY.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 PM CST SATURDAY FOR
SDZ038>040-050-052-053-057-058-063.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST SATURDAY FOR MNZ071-072.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1012 PM CST FRI MAR 8 2013
.DISCUSSION.../ISSUED AT 1010 PM CST/
PRECIPITATION BEGINNING TO EXPAND ACROSS THE AREA WITHS STRONG MID
LEVEL WARM AIR ADVECTION. TEMPERATURES ACROSS THE CWA HAVE GENERALLY
RISEN ABOVE FREEZING AT THIS POINT. THE RAP SEEMS TO HAVE THE
BEST HANDLE ON THE CURRENT SURFACE TEMPERATURES...AND IT SUGGESTS
MOST OF OUR NORTH STAYS JUST ABOVE FREEZING THROUGH THE NIGHT. THUS
THINKING MAINLY PLAIN RAIN...ALTHOUGH SOME ICY SPOTS ARE STILL
POSSIBLE ALONG THE HIGHWAY 14 CORRIDOR WHERE TEMPERATURES WILL FLIRT
WITH THE FREEZING MARK TROUGH THE NIGHT. STARTING TO SEE SOME
THUNDER ACROSS NORTHEAST NEBRASKA...AND WITH ELEVATED INSTABILITY
MOVING INTO OUR AREA...THINK A FEW LIGHTNING STRIKES WILL BE
POSSIBLE...MAINLY ALONG AND SOUTH OF INTERSTATE 90.
MODELS COMING INTO BETTER AGREEMENT ON EVOLUTION OF THE SYSTEM
TOMORROW...ALTHOUGH UNCERTAINTY STILL EXISTS. NAM...GFS AND SREF ALL
SHOWING WHAT COULD BE AN INTENSE MID LEVEL FRONT WEST OF THE JAMES
RIVER WITH SOME ELEVATED INSTABILITY AS WELL. THUS THOUGHT IS WE
COULD SEE A NARROW INTENSE BAND OF SNOW SOMEWHERE OUT THERE...BEST
GUESS AT THIS POINT FROM AROUND GREGORY COUNTY TO BEADLE. AS THE
NORTHERN STREAM WAVE PUSHES SOUTHEAST EXPECT DRY AIR AND INCREASING
SUBSIDENCE TO ENCROACH FROM THE NORTHWEST DURING THE AFTERNOON AND
EVENING. THIS SHOULD ACT TO DISSIPATE THIS BAND AS IT PUSHES OFF
SOUTHEAST. HOWEVER AS THE SOUTHERN STREAM WAVE AND PV ANOMALY EJECT
INTO THE CENTRAL PLAINS...EXPECT THE BAND TO REFORM FROM CENTRAL
NEBRASKA TO NORTHWEST IOWA. THIS WILL ALSO LIKELY BE A SOMEWHAT
NARROW CORRIDOR OF MODERATE TO POTENTIALLY HEAVY SNOW FOR SATURDAY
NIGHT. SO...CURRENT THOUGHTS ARE FOR LIGHT ICING ACROSS OUR FAR
NORTH AND ALSO WEST...GIVING WAY TO 3 TO 6 INCHES OF SNOW WEST OF
THE JAMES RIVER IN THAT INITIAL BAND. COULD EVEN SEE ISOLATED HIGHER
AMOUNTS...AND FUTURE SHIFTS WILL HAVE TO MONITOR NEW MODEL RUNS AND
POSSIBLY CONSIDER UPGRADING A FEW OF THOSE COUNTIES TO WARNINGS.
ANOTHER AREA OF 2 TO 6 INCHES SEEMS PROBABLE FROM YANKTON EAST INTO
NORTHWEST IOWA WITH THE SECOND BAND THAT FORMS. AGAIN ISOLATED
HIGHER AMOUNTS WILL BE POSSIBLE THERE AS WELL. PRETTY CONFIDENT WE
WILL NEED AN ADVISORY IN THAT AREA TOMORROW NIGHT...BUT CONFIDENCE
WAS TOO LOW FOR A WATCH. WINDS WILL PICK UP SATURDAY NIGHT INTO
SUNDAY LIKELY CREATING BLOWING AND DRIFTING ISSUES WITH ANY SNOW
THAT FALLS. SO FUTURE SHIFTS WILL ALSO HAVE TO DECIDE IF SNOW
AMOUNTS WILL BE HIGH ENOUGH...THAT COMBINED WITH THE WINDS...WOULD
WARRANT A WARNING FOR NORTHWEST IOWA. IN BETWEEN THESE TWO
BANDS...GENERALLY EXPECTING AN INCH OR TWO OF SNOW.
IN SUMMARY...MAINLY RAIN TONIGHT...CHANGING TO SNOW FROM NORTHWEST
TO SOUTHEAST TOMORROW INTO TOMORROW EVENING...ROUGHLY AFTER 9 AM
HURON...AFTER 1 PM MITCHELL...AFTER 6 PM SIOUX FALLS AND AFTER 9 PM
SIOUX CITY. EXPECTING TWO BANDS OF POTENTIALLY UP TO 6 INCHES OF
SNOW...ONE WEST OF THE JAMES RIVER AND ONE ACROSS NORTHWEST
IOWA...AND LESS IN BETWEEN. WITH THAT SAID...UNCERTAINTY STILL
EXISTS IN PLACEMENT OF THESE BANDS...AND WILL DEPEND ON STRENGTH OF
BOTH THE NORTHERN AND SOUTHERN STREAM. NEW 0Z GFS AND 0Z GEM HAVE
GONE AGAINST THE 12Z EC...0Z NAM AND 21Z SREF...IN THAT THEY ARE
SLIGHTLY FURTHER NORTH WITH BOTH BANDS...SUGGESTING A BIT MORE SNOW
FOR SIOUX FALLS. THUS STILL A FLUID SITUATION THAT WILL HAVE TO BE
MONITORED CLOSELY TONIGHT AND TOMORROW. CURRENT FORECAST FAVORS THE
MORE SOUTHERN SREF...NAM AND EC. /CHENARD
.PREVIOUS DISCUSSION.../ISSUED AT 253 PM CST/
QUITE A LOT OF CONVECTION IN THE DESERT SOUTHWEST WITH THE COMPACT
UPPER LEVEL LOW PRESSURE THAT WILL SOON BE AFFECTING OUR PART OF THE
COUNTRY. AS THIS WAVE MOVES INTO THE FOUR CORNERS REGION TONIGHT
SOUTHERLY FLOW WILL INCREASE ACROSS THE PLAINS. WITH DECENT LAPSE
RATES ALOFT AND VERY STRONG THERMAL/MOISTURE ADVECTION IN THE MID
LEVELS SUSPECT RAIN WILL DEVELOP QUICKLY TONIGHT OVER NEBRASKA INTO
SOUTH DAKOTA...IOWA AND MINNESOTA. THE LEAD WAVE CAUSING THIS
PRECIPITATION WILL SWING A DRY SLOT NORTHWARD LATE TONIGHT INTO
TOMORROW MORNING WHICH COULD SHUT DOWN THE SOUTHEAST HALF OF THE CWA
FOR AWHILE ON SATURDAY MORNING AND EARLY AFTERNOON AS SATURATION
ALOFT IS LOST AND TEMPERATURES LOWER ARE NOT COLD ENOUGH. RAINFALL
AMOUNTS TONIGHT IN MANY LOCATIONS LIKELY A QUARTER TO A HALF AN
INCH. WILL GO WITH A WINTER WEATHER ADVISORY FROM CHAMBERLAIN TO
HURON TO MARSHALL STARTING TONIGHT AND CONTINUING THROUGH SATURDAY
AFTERNOON. THE MAIN THREAT WILL BE FREEZING RAIN FROM ABOUT MIDNIGHT
THROUGH SUNRISE SATURDAY MORNING WHERE A TENTH TO TWO TENTHS OF AN
INCH OF ICING WILL BE POSSIBLE. WILL CONTINUE THROUGH THE AFTERNOON
AS SNOW WILL LIKELY DEVELOP...POSSIBLY ACCUMULATING AN INCH OR
TWO...AND WINDS WILL SIGNIFICANTLY INCREASE WITH GUSTS TO ABOUT 40
MPH POSSIBLE. ON TOP OF THE PRECIPITATION TONIGHT THE SOUTHERN HALF
OF THE CWA...MAINLY SOUTH OF INTERSTATE 90...COULD HEAR A LITTLE
THUNDER.
AS THIS POTENT WAVE SWINGS ONTO THE PLAINS SATURDAY DYNAMIC COOLING
WILL BEGIN TO QUICKLY SHIFT COLDER AIR INTO THE MID AND LOW LEVELS
AND TRANSITION THIS COLD AIR FROM WEST TO EAST. FREEZING RAIN WILL
TRANSITION TO SNOW IN THE WEST IN THE MORNING THEN CHANGE TO SNOW
FROM ABOUT MARSHALL TO SIOUX FALLS TO YANKTON AROUND 600 PM...THEN
IN NW IA AROUND 900 PM. THE STRONGEST FORCING LOOKS TO OCCUR FROM
ABOUT 0Z THROUGH 9Z IN THE SOUTHERN THIRD OF THE CWA. RIGHT NOW
THINKING MAINLY 1 TO 3 INCHES OF SNOW MOST LOCATIONS BUT THE BAND
THAT DEVELOPS IN NORTHERN NEBRASKA INTO NORTHWEST IOWA WILL HAVE THE
POTENTIAL TO PRODUCE 6 INCHES OR MORE OF SNOW IN A FAIRLY SHORT
PERIOD OF TIME. WILL HAVE TO KEEP AN EYE ON THE POTENTIAL FOR
BLOWING SNOW ON SATURDAY NIGHT AND SUNDAY MORNING IF MORE SNOW
OCCURS THAN EXPECTED AS GUSTS TO AROUND 40 TO 45 MPH IS NOT OUT OF
THE QUESTION.
SUSPECT WHAT WILL HAPPEN ON SATURDAY IS THE WARM ADVECTION BAND IN
THE NORTHERN CWA WILL FALL APART RATHER THAN TRANSITION FROM WEST TO
EAST. WHEN THE COLD FRONT ALOFT SWINGS INTO NORTHERN NEBRASKA
SATURDAY AFTERNOON A NEW BAND OF PRECIPITATION WILL DEVELOP AND
BECOME THE DOMINANT FEATURE. TRIED TO GET THIS POINT ACROSS IN THE
GRIDS BUT NOT EASY TO ACCOMPLISH. THIS SECOND BAND WILL BE THE ONE
THAT COULD PRODUCE SOME HEAVY SNOW AND ITS LOCATION WILL BE VERY
IMPORTANT. MOST OF THE SNOWFALL WILL BE EAST OF THE CWA BY 12Z
SUNDAY WITH A COLD AND WINDY SUNDAY EXPECTED.
HIGH PRESSURE RIDGE AXIS SLIDES ACROSS THE REGION ON SUNDAY
NIGHT...BRINGING DYING WINDS AND DECREASING CLOUDS. THIS IN
CONJUNCTION WITH LOW LEVEL COLD AIR ADVECTION WILL RESULT IN A
CHILLY NIGHT WITH LOWS IN THE SINGLE DIGITS AND TEENS.
THE HIGH MOVES EASTWARD ON MONDAY AS A SURFACE TROUGH APPROACHES
FROM THE WEST. THIS WILL PUT MUCH OF OUR AREA IN A RETURNING
SOUTHERLY FLOW...AND TEMPERATURES WILL RESPOND IN LIKE...ESPECIALLY
IN OUR SOUTHWEST...WITH HIGHS INTO THE MID 40S OVER THAT THAT AREA.
BACK TO THE EAST READINGS WILL TAPER DOWN INTO THE 30S...WITH
TEMPERATURES A LITTLE TRICKY DEPENDENT ON WHERE FRESH SNOW COVER IS
IS IN PLACE WITH SAT/SUN STORM. THE SURFACE TROUGH/BOUNDARY BEGINS
TO SLIDE INTO THE WEST LATE IN THE AFTERNOON...THEN SLIDING ACROSS
THE AREA ON MONDAY NIGHT. THE ECMWF/GEM WANTING TO SPIT OUT A LITTLE
PRECIPITATION WITH THIS IN THE LATE AFTERNOON OR EVENING AS AN UPPER
LEVEL SHORTWAVE TRACKS FROM NORTH DAKOTA TO THE LOWER GREAT LAKES
REGION OVERNIGHT. AT THE SAME TIME...THE GFS/NAM KEEP IT DRY AND
DECIDED TO GO THAT WAY WITH MOISTURE LOOKING TO BE PRETTY LIMITED.
IN THE EXTENDED...TUESDAY THROUGH FRIDAY...MODELS IN GOOD AGREEMENT
ON KEEPING OUR AREA IN A NORTHWESTERLY UPPER LEVEL FLOW THROUGH THE
THE PERIOD. HOWEVER...MODELS ARE IN LESS IN AGREEMENT ON THE
MESOSCALE FEATURES...WITH LOOSE CONSENSUS ON POSSIBLE PRECIPITATION
SOMETIME IN THE WEDNESDAY AND FRIDAY TIME FRAME AND KEPT SMALL
CHANCE POPS IN FOR THOSE PERIODS. TEMPERATURES THROUGH THE EXTENDED
LOOK TO REMAIN AT OR ABOVE NORMALS FOR THIS TIME OF YEAR.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
VFR CEILINGS THIS EVENING WILL GRADUALLY BECOME MVFR BY 06Z AND THEN
BECOME IFR 06Z THROUGH 00Z SUNDAY. LIGHT RAIN WILL BECOME WIDESPREAD
THIS EVENING WITH FREEZING RAIN POSSIBLE NORTH OF A HON-MWM LINE.
ISOLATED THUNDERSTORMS WILL DEVELOP ACROSS NORTHWEST IOWA AND
NORTHEAST NEBRASKA AFTER 06Z. BETWEEN 15Z AND 00Z ON SATURDAY...THE
RAIN AND FREEZING RAIN WILL GRADUALLY CHANGE TO SNOW WEST OF
INTERSTATE 29. VISIBILITIES WILL FREQUENTLY DROP BELOW 3 MILES AS
THE RAIN BECOMES WIDESPREAD TONIGHT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 PM CST SATURDAY FOR
SDZ038>040- 050-052-053-057-058-063.
MN...WINTER WEATHER ADVISORY UNTIL 6 PM CST SATURDAY FOR MNZ071-072.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS SAN ANGELO TX
212 PM CST SAT MAR 9 2013
.UPDATE...
FORECAST WAS UPDATED TO INCREASE POPS ACROSS EASTERN SECTIONS
THIS AFTERNOON AND TO INCLUDE SEVERE THUNDERSTORM WATCH 49.
&&
.DISCUSSION...
CONVECTION CONTINUES TO INCREASE ALONG THE PACIFIC FRONT/DRYLINE
EARLY THIS AFTERNOON WHICH CURRENTLY EXTENDS FROM JUST EAST OF
ABILENE...SOUTHWEST TO NEAR OZONA. LATEST RUC SEEMS TO HAVE A
DECENT HANDLE ON CURRENT ACTIVITY AND INDICATES ADDITIONAL
DEVELOPMENT ACROSS EASTERN PORTIONS THE HEARTLAND AND NORTHWEST
HILL COUNTRY LATER THIS AFTERNOON. PER SPC COORDINATION...SEVERE
THUNDERSTORM WATCH IS IN NOW IN EFFECT UNTIL 11 PM FOR THE
HEARTLAND AND CALLAHAN COUNTY. INCREASED POPS ACCORDINGLY ACROSS
EASTERN SECTIONS AND MADE ADJUSTMENTS TO TEMPS...DEWPOINTS AND
WINDS TO ACCOUNT FOR TRENDS. UPDATED ZONES SENT.
THUNDERSTORMS ARE EXPECTED TO INCREASE IN COVERAGE ACROSS THE
HEARTLAND AND NORTHWEST HILL COUNTRY LATER THIS EVENING WITH AN
ADDITIONAL THREAT FOR SEVERE STORMS INTO THE OVERNIGHT HOURS. THE
MAIN SEVERE WEATHER THREAT THIS AFTERNOON THROUGH TONIGHT WILL BE
LARGE HAIL AND DAMAGING WINDS BUT AN ISOLATED TORNADO CANNOT BE
RULED OUT.
&&
.PREV DISCUSSION... /ISSUED 1201 PM CST SAT MAR 9 2013/
DISCUSSION...
SEE 18Z AVIATION DISCUSSION.
AVIATION...
MAINLY AND MVFR FORECAST OVER THE NEXT 24 HOURS. SHOWERS AND
THUNDERSTORMS ARE POSSIBLE ACROSS MOST OF WEST CENTRAL TEXAS TODAY
AND INTO THIS EVENING AS A PACIFIC FRONT MOVE ACROSS THE AREA.
SHOWERS AND ISOLATED THUNDERSTORMS ARE POSSIBLE OVER
KABI...KSJT AND KSOA THROUGH MID AFTERNOON BUT CONFIDENCE NOT HIGH
ENOUGH TO INCLUDE ANYTHING BUT VICINITY FOR NOW. EXPECT MORE
CONVECTION TO DEVELOP OVER THE SOUTHEAST TERMINALS LATER THIS
EVENING. WILL INCLUDE VCTS OVER KBBD AND KJCT 03-06Z AND AND
REFINE THE FORECAST AS NEEDED BASED ON TRENDS. STORMS ARE
EXPECTED TO CLEAR OUT TOMORROW MORNING AFTER 10Z WITH A COLD
MOVING ACROSS THE AREA SUNDAY MORNING. EXPECT GUSTY NORTH TO
NORTHWEST WINDS BEHIND THE FRONT TO PERSIST INTO THE AFTERNOON
HOURS.
PREV DISCUSSION... /ISSUED 539 AM CST SAT MAR 9 2013/
DISCUSSION...
SEE THE 12Z AVIATION DISCUSSION BELOW.
AVIATION...
WIDESPREAD MVFR CIGS ARE AFFECTING MUCH OF WEST CENTRAL TX.
HOWEVER...IT APPEARS THAT GRAVITY WAVES ASSOCIATED WITH THE VERY
STRONG LOW LEVEL JET HAVE RESULTED IN AREAS OF SUBSIDENCE ON THE
LEE SIDE OF THE HIGHER TERRAIN FEATURES...CREATING EAST/WEST
CORRIDORS OF VFR CONDITIONS AT BOTH KABI AND KSJT. THESE AREAS
MAY BRIEFLY FILL IN BUT AS DRIER AIR ADVECTS INTO THE AREA WE WILL
SEE IMPROVING CIG HEIGHTS. CIGS ARE EXPECTED TO HANG ON THE
LONGEST AT KABI/KJCT BUT THESE AREAS SHOULD EVENTUALLY GO VFR AS
WELL BY MIDDAY. WINDS WILL VEER TO THE WEST SOUTHWEST AND REMAIN
GUSTY THIS MORNING. THESE GUSTY CONDITIONS WILL CONTINUE AT
KSJT/KABI BUT THE REMAINING AREAS SHOULD SEE SUSTAINED WINDS
GENERALLY 12 KTS OR LESS THIS AFTERNOON. A SECONDARY COLD FRONT
WILL MOVE ACROSS THE CWA OVERNIGHT AND SHIFT WINDS TO THE
NORTHWEST.
THE OTHER CONCERN THIS TAF PERIOD IS CONVECTION. A POTENT SYSTEM
WILL PROVIDE ISOLATED LIGHT RAIN SHOWERS THIS MORNING BUT THE
PRIMARY FOCUS WILL BE THIS EVENING IN THE VICINITY OF A PACIFIC
COLD FRONT...MAINLY OVER THE SOUTHEAST TERMINALS. I DID INCLUDE A
PROB30 GROUP FOR THUNDER AND MVFR CIGS AT KBBD/KJCT BEGINNING AT
23Z AS THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THIS AREA AFTER
PEAK HEATING.
JOHNSON
PREV DISCUSSION... /ISSUED 403 AM CST SAT MAR 9 2013/
SHORT TERM...
A BROAD TROUGH CONTINUES TO MOVE SLOWLY ACROSS THE WESTERN
CONUS...WITH THE PRIMARY CIRCULATION CURRENTLY LOCATED NEAR THE
FOUR CORNERS. SYNOPTIC SCALE ASCENT WILL CONTINUE TO OVERSPREAD
THE REGION AS THIS CYCLONE APPROACHES...INTERACTING WITH MORE
FOCUSED MESOSCALE FORCING AND ABUNDANT LOWER TROPOSPHERIC MOISTURE
TO ENHANCE CLOUD COVER AND PRECIP CHANCES. THE DYNAMICALLY
ENHANCED LOW LEVEL JET IS HOWLING AT AROUND 50 KTS...BUT THE CORE
OF THIS JET WILL SHIFT EAST DURING THE DAY AS THE TROUGH AXIS
MOVES INTO WEST CENTRAL TX. SOUTH WINDS ARE CURRENTLY 20-30 MPH AT
MANY AREAS WITH TEMPS IN THE LOW TO MID 60S.
LIGHT RAIN SHOWERS HAVE DEVELOPED IN THE PAST HOUR OVER WESTERN
NORTH TX...FROM ASPERMONT TO VERNON...AND SHOULD CONTINUE THIS
TREND OVER THE NEXT SEVERAL HOURS. LIGHT RAIN SHOWERS WILL BE
POSSIBLE ACROSS WEST CENTRAL TX THROUGH 18Z AND SHOULD BECOME MORE
ORGANIZED AS THE SURFACE TROUGH /OR WEAK PACIFIC COLD FRONT/ MOVES
EAST AND PROVIDES A STRONG LIFTING MECHANISM. OPTIMISTICALLY
SPEAKING...I THINK WE WILL SEE A BROKEN LINE OF SHOWERS MOVE
ACROSS THE BIG COUNTRY AND CONCHO VALLEY BETWEEN 12-18Z...SHIFTING
INTO THE HEARTLAND AND EASTERN BIG COUNTRY AFTER 18Z. POINT
SOUNDINGS STILL INDICATE THE PRESENCE OF AN ELEVATED MIXED
LAYER...WHICH IS EFFECTIVELY ERODED BY 16Z OR SO.
UNFORTUNATELY...THE BEST LIFT WILL BE OVER THE EASTERN ZONES BY
THIS TIME...MEANING THAT DEEP CONVECTION IS UNLIKELY FOR THE
WESTERN COUNTIES AND ONLY LIGHT PRECIPITATION IS ANTICIPATED THIS
MORNING. TEMPS WILL WARM INTO THE LOW/MID 70S ACROSS THE CWA THIS
AFTERNOON.
AS THE SURFACE BOUNDARY SLOWS UP OVER THE EASTERN ZONES...THE
LARGE SCALE ASCENT WILL CATCH UP AND ENHANCE THUNDERSTORM
CHANCES DURING THE AFTERNOON/EVENING. WITH THE CAP GONE...UPDRAFTS
SHOULD BE ABLE TO TAP INTO THE ANTICIPATED 1000-1500 J/KG OF
INSTABILITY. STRONG DEEP LAYER SHEAR SHOULD PROMOTE ORGANIZED
CONVECTION THIS AFTERNOON AND EVENING...MAINLY SOUTHEAST OF A
BROWNWOOD TO SONORA LINE. SEVERE STORMS WILL BE A POSSIBILITY
ACROSS THE SOUTHEAST THIS EVENING... WITH THE PRIMARY THREATS
BEING LARGE HAIL AND DAMAGING WINDS. THIS CONVECTION WILL LIKELY
CONTINUE ACROSS THE SOUTHEAST ZONES THROUGH 06Z BEFORE SLOWLY
SHIFTING TO THE SOUTH AS DRIER AIR ADVECTS INTO THE CWA FROM THE
WEST.
JOHNSON
LONG TERM...
NEXT WEEK APPEARS DRY IN THE COMPUTER MODELS. MID/UPPER LEVEL
MOISTURE SUNDAY MORNING WILL PUSH EAST AS THE AXIS OF AN UPPER
SHORTWAVE MOVES THROUGH THE REGION. IT WILL BE WINDY SUNDAY WITH
A TIGHT PRESSURE GRADIENT BEHIND A COLD FRONT. ALOFT...DRY
NORTHWEST FLOW WILL BECOME ZONAL BY TUESDAY. CLEAR SKIES AND
LIGHT WINDS ASSOCIATED WITH SURFACE RIDGING WILL BRING GOOD
RADIATIONAL COOLING MONDAY AND TUESDAY MORNINGS...WITH LOW LYING
AREAS FALLING BELOW THE FREEZING MARK. THERE WILL BE NICE REBOUND
IN TEMPERATURES TUESDAY WITH RETURN OF SOUTHERLY WINDS. A DRY
ATMOSPHERE AND SUNNY SKIES...WILL OTHERWISE ALLOW A LARGE DIURNAL
VARIATION IN TEMPERATURE NEXT WEEK.
FIRE WEATHER...
CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED TODAY DURING THE
MID/LATE AFTERNOON HOURS ACROSS THE WESTERN BIG COUNTRY AND
NORTHWEST CONCHO VALLEY. WEST SOUTHWEST 20 FT WINDS ARE EXPECTED
TO INCREASE TO 20 MPH IN THE WAKE OF A PACIFIC COLD FRONT WITH
RELATIVE HUMIDITY VALUES FALLING TO 15 TO 20 PERCENT. THE CRITICAL
FIRE WEATHER AREA WILL GENERALLY REMAIN ALONG/WEST OF A LINE FROM
HASKELL TO ROBERT LEE. WE MAY SEE A FEW SHOWERS THIS MORNING BUT
FINE FUELS ARE EXPECTED TO QUICKLY DRY. FARTHER SOUTH...WIND
SPEEDS ARE EXPECTED TO REMAIN 15-20 MPH...RESULTING IN ELEVATED
FIRE WEATHER CONDITIONS. RELATIVE HUMIDITIES WILL RECOVER TO 50-60
PERCENT TONIGHT WITH WEST TO NORTHWEST 20 FT WINDS GENERALLY 15
MPH OR LESS. EXPECT NORTH 20 FT WINDS OF 15-25 MPH ON SUNDAY AS A
SECONDARY COLD FRONT MOVES THROUGH THE AREA. HOWEVER...COOLER
CONDITIONS WILL KEEP RELATIVE HUMIDITIES ABOVE 20 PERCENT. MINIMUM
RELATIVE HUMIDITIES WILL FALL TO NEAR 15 PERCENT ON MONDAY WITH 20
FT WINDS WILL REMAIN UNDER 15 MPH. THE REST OF THE WEEK LOOKS
RELATIVELY QUIET.
JOHNSON
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 74 41 55 27 60 / 20 10 5 5 0
SAN ANGELO 79 42 59 28 66 / 20 10 5 5 0
JUNCTION 79 46 63 25 66 / 20 80 10 5 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: COKE...FISHER...HASKELL...JONES...NOLAN...STERLING.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1142 AM CST SAT MAR 9 2013
.AVIATION...
GUSTY WESTERLY WINDS SUSTAINED AT 25-30 KTS WILL BE COMMON AT THE
TERMINALS THROUGH THE AFTERNOON HOURS...AND A AWW REMAIN IN EFFECT
AT KLBB THROUGH 23Z. THESE WINDS WILL CONTINUE TO LOFT BLDU WHICH
MAY DROP VISIBILITIES INTO MVFR LEVELS AT KLBB. IN ADDITION...A
FEW SPRINKLES COULD LOCALLY ENHANCE THE WINDS AT KLBB INTO EARLY
THIS AFTERNOON. THE WINDS WILL GRADUALLY EASE A BIT THIS EVENING
BUT ANOTHER COLD FRONT WILL MOVE THROUGH EARLY SUNDAY MORNING.
WINDS WILL INCREASE AND SHIFT TO THE NORTH BEHIND THE FRONT AND
SPEEDS COULD AGAIN APPROACH AWW CRITERION. IN ADDITION...SCT-BKN
LOW CLOUDS MAY FILL IN BEHIND THE FRONT...AND COULD THREATEN OR
BREACH MVFR LEVELS.
&&
.PREV DISCUSSION... /ISSUED 1049 AM CST SAT MAR 9 2013/
UPDATE...
ONGOING FORECAST REMAINS IN GOOD SHAPE. PACIFIC FRONT HAS CLEARED
ALL BUT THE FAR SOUTHEAST ZONES AS OF 1030 AM. THUS...HAVE TRIMMED
POPS FOR ALL BUT THE FAR SOUTHEAST ZONES WHERE A FEW SHOWERS AND
ISOLATED STORMS WILL BE POSSIBLE FOR THE NEXT HOUR OR TWO. BEHIND
THE FRONT...GUSTY WESTERLY WIND WERE ALREADY SPILLING IN FROM
EASTERN NEW MEXICO WHERE SUSTAINED WINDS SPEEDS OF 30 TO 35 MPH
WERE ALREADY NOTED IN THE WTM DATA AT HOBBS...TATUM...DORA AND
MORTON. THESE STOUT WESTERLY WINDS WILL OVERSPREAD THE REMAINDER
OF THE FA THROUGH THE LATE MORNING AND INTO THE AFTERNOON HOURS.
THE LATEST RAP AND WRF-NAM DO INDICATE THE STRONGEST LOW TO MIDDLE
LEVEL WIND CORES WILL BE POSITIONED ACROSS THE TEXAS PANHANDLE
AND OVER THE SOUTHERN SOUTH AND ROLLING PLAINS INTO THE NORTHERN
PERMIAN BASIN THIS AFTERNOON. THIS MAY BE WHERE THE STRONGEST
WINDS OCCUR THROUGH THE AFTERNOON HOURS...THOUGH THE ENTIRE CWA
SHOULD SEE SUSTAINED WESTERLY WINDS OF 25 TO 35 MPH...INITIALLY ON
THE CAPROCK AND THEN SPREADING INTO THE ROLLING PLAINS THIS
AFTERNOON. ONGOING WIND ADVISORY REMAINS VALID. IN ADDITION...THE
GUSTY WINDS WILL ADVECT IN MUCH DRIER AIR AND LEAD TO A PERIOD OF
ELEVATED TO CRITICAL FIRE WEATHER THIS AFTERNOON...THOUGH THE
STATE OF THE FUELS SHOULD HELP MITIGATE THE OVERALL FIRE DANGER AND
THE ONGOING FIRE DANGER STATEMENT REMAINS VALID. WINDS WILL
DECREASE THIS EVENING...BUT THEY WILL BE REINVIGORATED EARLY
SUNDAY BEHIND A CANADIAN COLD FRONT.
PREV DISCUSSION... /ISSUED 449 AM CST SAT MAR 9 2013/
SHORT TERM...
DRYLINE HAS REMAINED STATIONED OVER EASTERN NEW MEXICO THIS MORNING
AS UPPER LOW CONTINUES SPINNING NEAR THE FOUR CORNERS REGION. EXPECT
THIS FEATURE AND ASSOCIATED LIFT TO PUSH QUICKLY EAST WITH SOME
ADDITIONAL SHOWER AND THUNDERSTORM ACTIVITY FORMING ALONG THE
ATTENDANT PACIFIC FRONT. BOUNDARY LAYER STABILIZATION WILL LIKELY
LIMIT THE SEVERITY OF ANY STORMS THAT DEVELOP...BUT ELEVATED
INSTABILITY OWING TO STEEPENING LAPSE RATES WILL NONETHELESS PROMOTE
THE THREAT OF SOME SMALL SIZED HAIL IF STORMS CAN BECOME
ESTABLISHED IN OUR REGION.
FOCUS WILL QUICKLY TURN TO DRIER AND WINDIER CONDITIONS IN WAKE OF
THIS LOW. AN INCREASING PRESSURE GRADIENT WILL DEVELOP AS THE UPPER
LOW PUSHES TOWARD WESTERN KANSAS AND CAUSES A SURFACE LOW TO DEEPEN.
WHILE THE 200 NAUTICAL MILE H70 HEIGHT GRADIENT HAS TRENDED DOWNWARD
TO NEAR 70 METERS...SUSTAINED SURFACE WINDS OF 30-35 MPH STILL LOOK
INEVITABLE...THUS WARRANTING A WIND ADVISORY FROM 16-00Z TODAY.
TROPOSPHERIC WIND MAXIMUMS WILL QUICKLY PUSH EAST THIS AFTERNOON
OVER THE ROLLING PLAINS...NEGATING HIGH WIND WARNING CRITERIA ON THE
FAVORED CAPROCK. BLOWING DUST WILL BE A CONCERN...ESPECIALLY ON THE
CAPROCK. HIGHER RAINFALL AMOUNTS AND COVERAGE LAST NIGHT AND THIS
MORNING WOULD HAVE LIMITED THIS POTENTIAL...BUT LOCATIONS SOUTHWEST
OF LUBBOCK GENERALLY ONLY PICKED UP A FEW HUNDREDTHS OF AN INCH.
AREAS AROUND PLAINVIEW TO LITTLEFIELD AND NORTHWEST RECEIVED A
QUARTER OF AN INCH WITH ISOLATED REPORTS UP TO NEAR HALF AN
INCH...BUT WIDESPREAD SIGNIFICANT RAIN BY AND LARGE WAS NOT THE RULE
AS SITES SOUTH AND EAST OF LUBBOCK REMAINED DRY.
A NORTHWEST TO SOUTHEAST GRADIENT IN TEMPERATURES WILL OCCUR THIS
AFTERNOON AS THE COOL NATURED PACIFIC FRONT PUSHES THROUGH...RANGING
FROM THE UPPER 50S ACROSS NORTHWEST ZONES TO MID 70S FOR THE
SOUTHEASTERN REACHES OF THE FORECAST AREA.
A CANADIAN FRONT WILL MOVE THROUGH TONIGHT FROM THE NORTHWEST AND KEEP
WINDS IN THE 15-25 MPH RANGE. COLD AIR ADVECTION WILL AID IN COOLING
OVERNIGHT LOWS INTO THE UPPER 20S TO MID 30S WEST OF THE
ESCARPMENT...WHILE AREAS TO THE EAST WILL ONLY BOTTOM OUT IN THE
UPPER 30S TO AROUND 40.
LONG TERM...
BY SUNDAY MORNING...THIS MORNING/S WEATHER MAKER SHOULD BE SITUATED
OVER THE CENTRAL PLAINS WITH A TROUGH TRAILING BACK TO THE BAJA
PENINSULA. A SUBTENDING LOBE WILL ROTATE AROUND THE BACK SIDE OF THE
LOW ON SUNDAY BRINGING A BIT OF REINFORCING ENERGY FOR A CANADIAN
FRONT DUE IN TONIGHT. NORTHWEST FLOW WILL THEN PERSIST FOR THE
REMAINDER OF THE EXTENDED THOUGH SLOWLY FLATTENING AS NEGATIVELY
TILTED RIDGE EXTENDS FROM THE DESERT SOUTHWEST INTO EXTREME WESTERN
CANADA.
AS FRONT PUSHES THROUGH EARLY SUNDAY...CONVECTION LOOKS TO BREAK
OUT TO OUR SOUTHEAST AND CONTINUE IN THAT DIRECTION. TO OUR
NORTH...SOME LIGHT WRAP-AROUND PRECIPITATION SHOULD BE ABLE TO GET
GOING ON THE WESTERN PERIPHERY OF THE UPPER LOW AND MAY MAKE IT AS
FAR SOUTH AS THE TEXAS PANHANDLE. STILL...WILL KEEP FORECAST DRY
FOR OUR CWFA. WINDS WILL BE QUITE STOUT ON SUNDAY BEHIND THE FRONT
WITH SPEEDS IN THE 20 TO 30 MPH RANGE. AFTER RETURN FLOW STARTS TO
GET GOING LATE MONDAY...NEXT WEAK FRONT WILL TRY TO MAKE IT INTO
THE NORTHWESTERN PANHANDLE TUESDAY MORNING AND AGAIN THURSDAY AND
SATURDAY MORNINGS WITH LITTLE TO SHOW OTHER THAN A WIND SHIFT. DRY
CONDITIONS TO PREVAIL WITH LOTS OF SUN FOR SPRING BREAK.
FIRE WEATHER...
MUCH DRIER AND WINDIER CONDITIONS BEHIND A PACIFIC FRONT WILL DROP
MINIMUM RELATIVE HUMIDITY VALUES INTO THE TEENS TO LOW 20S AREAWIDE.
PORTIONS OF THE SOUTHERN SOUTH PLAINS WILL DIP TO 15 PERCENT OR
BELOW ALONG WITH MUCH OF THE ROLLING PLAINS WHERE TEMPERATURES WILL
BE WARMER. WINDS WILL BE SUSTAINED AROUND 30 MPH WITH GUSTS OF 40-50
MPH. TEMPERATURES NOT TOO FAR ABOVE AVERAGE...A LACK OF DRY
FUELS...AND A QUICKLY EASTWARD MOVING MID LEVEL JET MAXIMUM SHOULD
PRECLUDE WIDESPREAD AND LONG DURATION RED FLAG MINUTES. WILL STILL
EXPERIENCE ELEVATED TO CRITICAL CONDITIONS THIS AFTERNOON...SO WILL
ISSUE A FIRE DANGER STATEMENT TO CONVEY THIS THREAT.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 57 27 47 25 60 / 0 0 0 0 0
TULIA 60 31 45 23 61 / 10 0 0 0 0
PLAINVIEW 61 31 47 23 62 / 10 0 0 0 0
LEVELLAND 63 33 51 27 64 / 0 0 0 0 0
LUBBOCK 64 34 50 26 63 / 10 0 0 0 0
DENVER CITY 63 33 52 29 63 / 0 0 0 0 0
BROWNFIELD 65 35 52 28 64 / 10 0 0 0 0
CHILDRESS 70 37 50 29 60 / 10 0 0 0 0
SPUR 69 40 52 28 62 / 10 0 0 0 0
ASPERMONT 76 39 52 29 61 / 30 0 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: TXZ021>044.
&&
$$
23/07/23
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
1049 AM CST SAT MAR 9 2013
.UPDATE...
ONGOING FORECAST REMAINS IN GOOD SHAPE. PACIFIC FRONT HAS CLEARED
ALL BUT THE FAR SOUTHEAST ZONES AS OF 1030 AM. THUS...HAVE TRIMMED
POPS FOR ALL BUT THE FAR SOUTHEAST ZONES WHERE A FEW SHOWERS AND
ISOLATED STORMS WILL BE POSSIBLE FOR THE NEXT HOUR OR TWO. BEHIND
THE FRONT...GUSTY WESTERLY WIND WERE ALREADY SPILLING IN FROM
EASTERN NEW MEXICO WHERE SUSTAINED WINDS SPEEDS OF 30 TO 35 MPH
WERE ALREADY NOTED IN THE WTM DATA AT HOBBS...TATUM...DORA AND
MORTON. THESE STOUT WESTERLY WINDS WILL OVERSPREAD THE REMAINDER
OF THE FA THROUGH THE LATE MORNING AND INTO THE AFTERNOON HOURS.
THE LATEST RAP AND WRF-NAM DO INDICATE THE STRONGEST LOW TO MIDDLE
LEVEL WIND CORES WILL BE POSITIONED ACROSS THE TEXAS PANHANDLE
AND OVER THE SOUTHERN SOUTH AND ROLLING PLAINS INTO THE NORTHERN
PERMIAN BASIN THIS AFTERNOON. THIS MAY BE WHERE THE STRONGEST
WINDS OCCUR THROUGH THE AFTERNOON HOURS...THOUGH THE ENTIRE CWA
SHOULD SEE SUSTAINED WESTERLY WINDS OF 25 TO 35 MPH...INITIALLY ON
THE CAPROCK AND THEN SPREADING INTO THE ROLLING PLAINS THIS
AFTERNOON. ONGOING WIND ADVISORY REMAINS VALID. IN ADDITION...THE
GUSTY WINDS WILL ADVECT IN MUCH DRIER AIR AND LEAD TO A PERIOD OF
ELEVATED TO CRITICAL FIRE WEATHER THIS AFTERNOON...THOUGH THE
STATE OF THE FUELS SHOULD HELP MITIGATE THE OVERALL FIRE DANGER AND
THE ONGOING FIRE DANGER STATEMENT REMAINS VALID. WINDS WILL
DECREASE THIS EVENING...BUT THEY WILL BE REINVIGORATED EARLY
SUNDAY BEHIND A CANADIAN COLD FRONT.
&&
.PREV DISCUSSION... /ISSUED 558 AM CST SAT MAR 9 2013/
AVIATION...
AN ISOLATED SHOWER OR THUNDERSTORM MAY STILL DEVELOP AHEAD OF THE
PACIFIC FRONT THIS MORNING...BUT CHANCES ARE TOO LOW FOR MENTION
WITHIN EITHER THE KLBB OR KCDS TERMINALS. KCDS SHOULD SEE SOME
MVFR CEILINGS EARLY THIS MORNING BEFORE LIFTING BY MID MORNING.
SOUTH WINDS WILL INCREASE AND VEER FROM NEAR 12 KNOTS EARLY THIS
MORNING TO NEAR 30 KNOTS WITH GUSTS OF 40-45 KNOTS OUT OF THE WEST
BY LATE MORNING. BLOWING DUST SHOULD BE PREVALENT ENOUGH TO
PRODUCE MVFR VISIBILITIES AT KLBB FOR MUCH OF THE TIME LATER THIS
MORNING AND THIS AFTERNOON GIVEN THE LACK OF ANY RAINFALL LAST
NIGHT OR THIS MORNING. A LULL IN WINDS WILL TAKE PLACE AT BOTH
TERMINALS FROM SHORTLY AFTER SUNSET THROUGH AN HOUR OR TWO AFTER
MIDNIGHT...BEFORE A CANADIAN COLD FRONT MOVES IN FROM THE NORTH TO
RAMP NORTHWEST WINDS UP TO NEAR 20 KNOTS WITH GUSTS TO 30 KNOTS.
CLOUDS SHOULD BECOME REESTABLISHED AROUND FL030...BUT PREVAILING
CEILINGS ARE NOT FORECASTED AT THIS TIME.
PREV DISCUSSION... /ISSUED 449 AM CST SAT MAR 9 2013/
SHORT TERM...
DRYLINE HAS REMAINED STATIONED OVER EASTERN NEW MEXICO THIS MORNING
AS UPPER LOW CONTINUES SPINNING NEAR THE FOUR CORNERS REGION. EXPECT
THIS FEATURE AND ASSOCIATED LIFT TO PUSH QUICKLY EAST WITH SOME
ADDITIONAL SHOWER AND THUNDERSTORM ACTIVITY FORMING ALONG THE
ATTENDANT PACIFIC FRONT. BOUNDARY LAYER STABILIZATION WILL LIKELY
LIMIT THE SEVERITY OF ANY STORMS THAT DEVELOP...BUT ELEVATED
INSTABILITY OWING TO STEEPENING LAPSE RATES WILL NONETHELESS PROMOTE
THE THREAT OF SOME SMALL SIZED HAIL IF STORMS CAN BECOME
ESTABLISHED IN OUR REGION.
FOCUS WILL QUICKLY TURN TO DRIER AND WINDIER CONDITIONS IN WAKE OF
THIS LOW. AN INCREASING PRESSURE GRADIENT WILL DEVELOP AS THE UPPER
LOW PUSHES TOWARD WESTERN KANSAS AND CAUSES A SURFACE LOW TO DEEPEN.
WHILE THE 200 NAUTICAL MILE H70 HEIGHT GRADIENT HAS TRENDED DOWNWARD
TO NEAR 70 METERS...SUSTAINED SURFACE WINDS OF 30-35 MPH STILL LOOK
INEVITABLE...THUS WARRANTING A WIND ADVISORY FROM 16-00Z TODAY.
TROPOSPHERIC WIND MAXIMUMS WILL QUICKLY PUSH EAST THIS AFTERNOON
OVER THE ROLLING PLAINS...NEGATING HIGH WIND WARNING CRITERIA ON THE
FAVORED CAPROCK. BLOWING DUST WILL BE A CONCERN...ESPECIALLY ON THE
CAPROCK. HIGHER RAINFALL AMOUNTS AND COVERAGE LAST NIGHT AND THIS
MORNING WOULD HAVE LIMITED THIS POTENTIAL...BUT LOCATIONS SOUTHWEST
OF LUBBOCK GENERALLY ONLY PICKED UP A FEW HUNDREDTHS OF AN INCH.
AREAS AROUND PLAINVIEW TO LITTLEFIELD AND NORTHWEST RECEIVED A
QUARTER OF AN INCH WITH ISOLATED REPORTS UP TO NEAR HALF AN
INCH...BUT WIDESPREAD SIGNIFICANT RAIN BY AND LARGE WAS NOT THE RULE
AS SITES SOUTH AND EAST OF LUBBOCK REMAINED DRY.
A NORTHWEST TO SOUTHEAST GRADIENT IN TEMPERATURES WILL OCCUR THIS
AFTERNOON AS THE COOL NATURED PACIFIC FRONT PUSHES THROUGH...RANGING
FROM THE UPPER 50S ACROSS NORTHWEST ZONES TO MID 70S FOR THE
SOUTHEASTERN REACHES OF THE FORECAST AREA.
A CANADIAN FRONT WILL MOVE THROUGH TONIGHT FROM THE NORTHWEST AND KEEP
WINDS IN THE 15-25 MPH RANGE. COLD AIR ADVECTION WILL AID IN COOLING
OVERNIGHT LOWS INTO THE UPPER 20S TO MID 30S WEST OF THE
ESCARPMENT...WHILE AREAS TO THE EAST WILL ONLY BOTTOM OUT IN THE
UPPER 30S TO AROUND 40.
LONG TERM...
BY SUNDAY MORNING...THIS MORNING/S WEATHER MAKER SHOULD BE SITUATED
OVER THE CENTRAL PLAINS WITH A TROUGH TRAILING BACK TO THE BAJA
PENINSULA. A SUBTENDING LOBE WILL ROTATE AROUND THE BACK SIDE OF THE
LOW ON SUNDAY BRINGING A BIT OF REINFORCING ENERGY FOR A CANADIAN
FRONT DUE IN TONIGHT. NORTHWEST FLOW WILL THEN PERSIST FOR THE
REMAINDER OF THE EXTENDED THOUGH SLOWLY FLATTENING AS NEGATIVELY
TILTED RIDGE EXTENDS FROM THE DESERT SOUTHWEST INTO EXTREME WESTERN
CANADA.
AS FRONT PUSHES THROUGH EARLY SUNDAY...CONVECTION LOOKS TO BREAK
OUT TO OUR SOUTHEAST AND CONTINUE IN THAT DIRECTION. TO OUR
NORTH...SOME LIGHT WRAP-AROUND PRECIPITATION SHOULD BE ABLE TO GET
GOING ON THE WESTERN PERIPHERY OF THE UPPER LOW AND MAY MAKE IT AS
FAR SOUTH AS THE TEXAS PANHANDLE. STILL...WILL KEEP FORECAST DRY
FOR OUR CWFA. WINDS WILL BE QUITE STOUT ON SUNDAY BEHIND THE FRONT
WITH SPEEDS IN THE 20 TO 30 MPH RANGE. AFTER RETURN FLOW STARTS TO
GET GOING LATE MONDAY...NEXT WEAK FRONT WILL TRY TO MAKE IT INTO
THE NORTHWESTERN PANHANDLE TUESDAY MORNING AND AGAIN THURSDAY AND
SATURDAY MORNINGS WITH LITTLE TO SHOW OTHER THAN A WIND SHIFT. DRY
CONDITIONS TO PREVAIL WITH LOTS OF SUN FOR SPRING BREAK.
FIRE WEATHER...
MUCH DRIER AND WINDIER CONDITIONS BEHIND A PACIFIC FRONT WILL DROP
MINIMUM RELATIVE HUMIDITY VALUES INTO THE TEENS TO LOW 20S AREAWIDE.
PORTIONS OF THE SOUTHERN SOUTH PLAINS WILL DIP TO 15 PERCENT OR
BELOW ALONG WITH MUCH OF THE ROLLING PLAINS WHERE TEMPERATURES WILL
BE WARMER. WINDS WILL BE SUSTAINED AROUND 30 MPH WITH GUSTS OF 40-50
MPH. TEMPERATURES NOT TOO FAR ABOVE AVERAGE...A LACK OF DRY
FUELS...AND A QUICKLY EASTWARD MOVING MID LEVEL JET MAXIMUM SHOULD
PRECLUDE WIDESPREAD AND LONG DURATION RED FLAG MINUTES. WILL STILL
EXPERIENCE ELEVATED TO CRITICAL CONDITIONS THIS AFTERNOON...SO WILL
ISSUE A FIRE DANGER STATEMENT TO CONVEY THIS THREAT.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 57 27 47 25 60 / 0 0 0 0 0
TULIA 60 31 45 23 61 / 10 0 0 0 0
PLAINVIEW 61 31 47 23 62 / 10 0 0 0 0
LEVELLAND 63 33 51 27 64 / 0 0 0 0 0
LUBBOCK 64 34 50 26 63 / 10 0 0 0 0
DENVER CITY 63 33 52 29 63 / 0 0 0 0 0
BROWNFIELD 65 35 52 28 64 / 10 0 0 0 0
CHILDRESS 70 37 50 29 60 / 10 0 0 0 0
SPUR 69 40 52 28 62 / 10 0 0 0 0
ASPERMONT 76 39 52 29 61 / 30 0 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING
ZONES: TXZ021>044.
&&
$$
23/07
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1112 PM MDT SUN MAR 10 2013
.UPDATE...
ISSUED AT 540 PM MDT SUN MAR 10 2013
WINDS HAD DECREASED TO BELOW ADVISORY CRITERIA SO WIND ADVISORY
HAS BEEN CANCELLED.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 143 PM MDT SUN MAR 10 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS SHOW LONG WAVE TROUGH
EXTENDING FROM GREAT LAKES ACROSS THE THE CENTRAL PLAINS WITH BASE
OF TROUGH OVER BAJA PENINSULA. STACKED H7/H5 CLOSED LOW CENTER IS
CURRENTLY OVER NE KANSAS WITH SHORTWAVE RIDGE BUILDING ACROSS
WESTERN US INTO THE NORTHERN PLAINS ON THE BACK SIDE OF THIS SYSTEM.
BETWEEN THE RIDGE AND CLOSED LOW A STRONG AXIS OF SUBSIDENCE IN IN
PLACE ACROSS OUR CWA. TIGHT PRESSURE GRADIENT IS CURRENTLY IN PLACE
ACROSS THE EASTERN HALF OF THE CWA WITH HIGH PRESSURE BUILDING OVER
EASTERN COLORADO AND STRONG SURFACE LOW PRESSURE CENTERED OVER
MISSOURI.
GRADIENT WILL CONTINUE TO WEAKEN AS LARGE SCALE SYSTEM PULLS EAST
THIS AFTERNOON AND HIGH PRESSURE CONTINUES TO BUILD OVER THE CWA. WE
ARE ALREADY SEEING WINDS DECREASE BELOW ADVISORY CRITERIA OVER THE
NW HALF OF THE CWA. WINDS CONTINUE TO HOVER RIGHT AT OR ABOVE
ADVISORY CRITERIA WITH BETTER THAN ANTICIPATED AFTERNOON MIXING
ACROSS THE SE HALF OF THE AREA. I DECIDED TO EXTEND ADVISORY
00Z...THOUGH WE MIGHT BE ABLE TO EXPIRE THE ADVISORY EARLY
ESPECIALLY FOR THE NW COUNTIES.
WINDS WILL DECREASE RAPIDLY AROUND SUNSET WITH LIGHT W/NW WINDS
EXPECTED OVERNIGHT TONIGHT. WITH SHORTWAVE RIDGE BUILDING EAST FLOW
ALOFT WITH SHIFT TO A NW WITH LEE TROUGH BEGINNING TO REDEVELOP OVER
EASTERN COLORADO BY 12Z TONIGHT. EARLY THIS AFTERNOON EASTERN
LOCATIONS COULD STILL SEE A FEW FLURRIES AS ENERGY ROTATES ON THE
BACK SIDE OF UPPER LOW...HOWEVER BEYOND THIS THE FORECAST SHOULD
REMAIN DRY THROUGH THE DAYTIME PERIOD MONDAY.
THERE WILL BE A MODERATION OF THE AIR MASS OVER OUR CWA FROM THE
WEST TO THE EAST TONIGHT WHICH WILL CONTINUE THROUGH THE DAY
MONDAY. IT IS DIFFICULT TO TELL WHAT IMPACT RECENT SNOW PACK WILL
HAVE ON TEMPS TONIGHT AND MONDAY WITH PAST EVENTS WARMING MUCH
FASTER THAN ORIGINALLY INDICATED. FOR NOW I THINK OUR LOWS SHOULD
COOL TO LOW TO MID TEENS FOR MOST LOCATIONS DESPITE WARMING
AIRMASS. H85 TEMPS ON MON WOULD SUPPORT HIGHS IN THE MID 50S TO
AROUND 60F UNDER IDEAL MIXING. TO ACCOUNT FOR SNOW I KEPT HIGH
FORECAST MON ABOUT 5-10F COOLER RANGING FROM UPPER 40S IN THE
NORTH TO MID 50S IN THE SOUTH WHERE LESS SNOW FELL.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 143 PM MDT SUN MAR 10 2013
LONG TERM FORECAST CONCERNS ARE THE POTENTIAL FOR FLURRIES MONDAY
NIGHT AND THE POSSIBILITY OF PRECIPITATION DURING NEXT
WEEKEND.
NORTHWEST FLOW ALOFT OVER THE FORECAST AREA AS THE RIDGE AMPLIFIES
OVER THE WESTERN UNITED STATES WILL CARRY A SHORT WAVE TROUGH
THROUGH THE CENTRAL HIGH PLAINS REGION OVERNIGHT MONDAY NIGHT.
THERE MAY BE A FEW FLURRIES ASSOCIATED WITH THIS WAVE AS MID AND
LOWER LEVEL MOISTURE INCREASES. WINDS MAY ALSO BE GUSTY OVERNIGHT
AND INTO THE DAY ON TUESDAY AS SUBSIDENCE BEHIND THIS WEAK WAVE
HELPS MIX STRONGER WINDS TO THE SURFACE.
DRY CONDITIONS WILL PERSIST THROUGH THE REMAINDER OF THE WORK WEEK
AS THE BROAD RIDGE OVER THE WESTERN UNITED STATES MOVES EASTWARD
FROM THE INTERMOUNTAIN REGION TO THE ROCKIES AND HIGH PLAINS. THE
RIDGE WILL BEGIN TO FLATTEN THURSDAY NIGHT AND FRIDAY AS A SERIES
OF WEAKER SHORT WAVE TROUGHS BEGINS TO MOVE INTO THE WEST COAST
AND ACROSS THE TOP OF THE RIDGE. MUCH WARMER THAN NORMAL
TEMPERATURES ARE EXPECTED ACROSS THE FORECAST AREA THURSDAY AND
FRIDAY.
THE FLOW FLATTENS ACROSS THE UNITED STATES TOWARDS THE END OF THE
WEEK AND INTO THE WEEKEND FOR A MORE PROGRESSIVE PATTERN. BETWEEN
FRIDAY NIGHT AND SUNDAY THE GFS AND ECMWF BEGIN TO DIVERGE IN
THERE INDIVIDUAL HANDLING OF SUBSEQUENT SHORT WAVES AND THE LARGER
SCALE UPPER TROUGH MOVING INTO THE WESTERN UNITED STATES.
DEPENDING UPON WHICH SOLUTION PANS OUT...THE CENTRAL HIGH PLAINS
REGION COULD SEE COOLER TEMPERATURES...ALTHOUGH STILL WARMER THAN
AVERAGE FOR THIS TIME OF YEAR...ALONG WITH SOME LIGHT SHOWERS
MOVING ACROSS THE AREA ON SATURDAY...OR COOLER TEMPERATURES AND A
FEW SPRINKLES ACROSS PORTIONS OF THE AREA ON SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1109 PM MDT SUN MAR 10 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD. AFTER THE SUN
COMES THE WINDS WILL BECOME NORTHWEST AND GUSTY AS A SURFACE
TROUGH MOVES THROUGH THE AREA. WINDS WILL BECOME MUCH LIGHTER NEAR
00Z. EVEN THOUGH CONDITIONS WILL REMAIN VFR...CEILINGS WILL LOWER
AND THICKEN. TOWARD THE END OF THIS PERIOD OR JUST AFTER...THERE
WILL BE THE POSSIBILITY OF VERY LIGHT SNOW. SINCE IT IS AT THE END
OF THIS PERIOD...CHOSE NOT TOO MENTION IT AT THIS TIME.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
105 AM EDT MON MAR 11 2013
...Updated Aviation Discussion...
.Forecast Update...
Issued at 1005 PM EST Sun Mar 10 2013
Rain band is progressing slowly eastward across the western forecast
area. Dewpoints have been slow to come up over the eastern half, but
that should change as this batch of moisture aloft saturates the
lower levels. Expect the rain shield to expand as we get a low level
surge of winds overnight. Latest RAP indicating between 45-55 knots
at 2 kft. Diffluent flow aloft will combine with these low level
winds to create additional rains. Did not make any changes to the
pops, but did bring the near term grids closer to current values.
These changes are transparent in the zones, so not sending out a
zone update at this point. Still looking for areal averages for rain
between an inch and an inch and a half by Monday evening.
&&
.Short Term (Now - Monday Night)...
Issued at 300 PM EDT Sun Mar 10 2013
The approaching surface low continues to strengthen as the
upper-level trough is amplifying over the central CONUS. The surface
low, currently across the Middle Mississippi River Valley, will move
north-northeast to Lake Michigan by Monday morning. This more
northward movement of the surface low will cause the frontal
boundary to slowly progress eastward.
Under cloudy skies, a few sprinkles were present this morning. This
quickly dissipated and cloud cover began to break up by late
morning. This has allowed temperatures to range from the mid 60s to
low 70s early this afternoon, with a little more warming possible.
Southerly winds have also increased across the region, in response
to the strengthening pressure gradient. Gusts have reached the low
to mid 30 mph range, mainly across our southwest CWA (Bowling Green
region) and believe a few more hours of gusts similar to this will
be possible. Lighter wind gusts will be possible across the east and
northeast forecast area.
By this evening, the frontal boundary will approach from the west.
Widespread rain, moderate at times, will move across the western
forecast area late this evening, the central forecast area during
the early morning hours to about daybreak, and across the eastern
forecast area from about daybreak through midday Monday. Expect
precipitation efficient rainfall, as warm-cloud depths range between
8-9K feet, total PWs range between 1 and 1.2 inches, and sub-cloud
layer relative humidity will be 70+ percent. Still looking for
0.75-1.4 inches of rainfall for overall QPF, with the higher amounts
being across south-central Kentucky. This should not cause may
issues, with just some nuisance ponding/flooding and rises on area
rivers and streams. Some low-top showers could develop on the back
side of the departing main precip shield Monday afternoon and exit
the eastern forecast area during the evening hours. Will continue
PoPs Monday afternoon and trend them back from west to east, ending
PoPs around midnight in the east. Still appears showers could mix
down some stronger, sub-severe winds. So, winds of 40 mph are
possible, especially with already strong gradient winds.
Strong gusty winds will subside a bit tonight and transition to
westerly Monday afternoon and evening, as the front pushes through
the forecast area. Expect non-diurnal temperature trends Sunday
night and Monday as colder air filters southeast across the forecast
area. Temperatures will be quite mild tonight, with readings ranging
from the low to mid 50s. Temperatures will trend cooler from
northwest to southeast through the day Monday, with generally low 40
in the northwest to around 50 in the southeast expected by early
Monday evening. Temperatures will continue to cool Monday night,
with lows in the lower 30s anticipated.
.Long Term (Tuesday Night through Sunday)...
Issued at 340 PM EDT Sun Mar 10 2013
Tuesday Night through Thursday Night...
The medium range models are in fairly decent agreement for the
middle of the week. The multi-model consensus is in agreement that
a fairly stout upper trough will push through the region around
mid-week bringing colder than normal temperatures back into the
region. Within the upper trough, the models continue to struggle
with bringing a mid-level vorticity max through the base of the
trough. Using the consensus mean, it appears that this feature will
most likely pass to our north and just bring some clouds down into
the region Wednesday afternoon and evening. The upper trough will
shift to the east on Thursday as some mid-level ridging builds to
the west of the area. We will remain in a northwesterly flow aloft
and will be watching for another mid-level vort max to swing through
the region Thursday night. The timing of this vort max is very much
in question as the deterministic models continue to have timing
issues. Yesterday`s solutions showed the GFS being more progressive
and faster, but today`s solutions show a faster Euro and slower
GFS. For now, will keep some low chc PoPs in for Thursday night
until some better forecast/model continuity.
As for temperatures, the multi-model consensus has trended a little
cooler over the last 24 hours. Therefore, it appears that going a
little cooler on temperatures is probably a good bet at this point,
but nothing too earth shattering. Lows Tuesday and Wednesday night
will cool into the 20s. Highs Tuesday will probably only warm into
the lower 40s in the north with lower-middle 40s in the south. A
little bit of a warm up is expected Thursday with readings warming
into the upper 40s in the north and lower 50s in the south. Lows
Thursday night look to cool back into the mid 30s.
Friday through Sunday...
The long term portion of the forecast can be summed up as a low
confidence forecast at best given the large amount of spread in
today`s deterministic guidance. Utilizing an average of the
multi-model consensus, the upper ridge over the east looks to
eventually get replaced with a broad trough as we get toward the end
of the forecast period. The Euro and GFS both handle the mid-level
wave differently and with different speeds. The GFS lets the wave
slide east and results in a quasi-stationary boundary remaining over
the region from this weekend and into next. On the other hand, the
Euro has been trending with pushing the system on through with the
boundary setting up to our south with a more significant system
developing just beyond the forecast period. Interestingly enough,
the pattern is almost reminiscent of the system that passed through
the Mid-Atlantic last week...though the Euro solutions are a little
more to the south of last weeks track. For now, plan on leaving
conditions partly to mostly cloudy through the period. Will
maintain some low chance PoPs in the forecast but hold off on making
more significant adjustments until some better forecast convergence
emerges.
Temperatures are equally challenging as well. The overall pattern
does support above normal temperatures with highs on Friday warming
into the upper 50s to the lower 60s. Saturday could be a bit warmer
with readings in the lower to middle 60s. Depending on the eventual
frontal position, we trended temperatures back a bit on Sunday and
have gone with a more consensus blend here which results in
temperatures in the middle to upper 50s. Overnight lows through the
period will likely average in the 40s.
&&
.Aviation (06Z TAF Issuance)...
Issued at 104 AM EDT Sun Mar 11 2013
Surface low is now over the lower Great Lakes with upper level low
over southern Iowa. A cold front extends southward from the surface
low along the middle Mississippi River Valley, and will slowly push
east toward the TAF sites through the overnight. Widespread rain
showers are now filtering across the SDF/BWG terminal and will
continue to do so through the overnight, however conditions should
stay generally VFR, outside of the heaviest showers where a brief
drop to MVFR vis is possible. As we approach dawn, the frontal
boundary will begin to move through, and with the lighter winds will
come lower ceilings. Will stay above the MVFR/IFR threshold for now,
but cannot rule it out at this point. Showery activity will persists
through the early afternoon behind the front, as the upper level
trough axis to the west begins to move through. Will return to VFR
by early to mid afternoon with a gusty west wind between 10 and 20
mph and a few gusts around 25 mph.
LEX will widespread rain onset toward dawn, with a brief drop into
the MVFR category for visibilities through midday. Then by mid
afternoon, front moves through with low MVFR ceilings and light rain
shower activity persisting into the early evening hours. Conditions
should return to VFR by mid evening with a steady west wind.
One other note, decided to let low level wind shear mention go as
soundings across the area do not show much of a low level inversion
and low level winds in the 1000-2000 foot range are marginal at this
point.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........RJS
Short Term.......MJP
Long Term........MJ
Aviation.........BJS
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
600 AM EDT MON MAR 11 2013
.SYNOPSIS...
HIGH PRESSURE WILL RESIDE ALONG THE MID-ATLANTIC COAST TODAY. A
COLD FRONT WILL APPROACH TONIGHT...AND THEN MOVE ACROSS THE AREA
DURING THE MORNING AND EARLY AFTERNOON ON TUESDAY. AN UPPER TROUGH
IS EXPECTED TO LINGER OVER THE NORTHEAST AND MID-ATLANTIC STATES
THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A LGT SE RETURN FLOW HAS DEVELOPED IN RESPONSE TO HIPRES SHIFTING
OFF THE ERN SEABOARD. ONSHORE COMPONENT TO THE FLOW HAS ADVECTED
MARINE LAYER INLAND ERY THIS MRNG. 11U-3.9U SAT IMAGERY SHOWS
STRATUS DECK HAS ADVANCED WESTWARD TO ABOUT I-95 AT 07Z. FCST
REGARDING INLAND PROGRESSION OF STRATUS DECK ERY THIS MRNG WAS IN
BETWEEN THE HRRR AND NAM...WHICH HAVE BOTH CAPTURED THIS STRATUS
EVENT WELL THUS FAR. THE HRRR DEVELOPS STRATUS AS FAR WEST AS IAD TO
FDK TO EZF WHILE THE 00Z NAM TAKES IT AS FAR INLAND AS MRB BY
SUNRISE.
LOPRES WILL TRACK NEWD ACROSS THE UPPER MIDWEST TDA WHILE ATTENDANT
COLD FRONT MOVES THRU THE OH VLY. DEEP SLY FLOW WITHIN PRE-FRONTAL
WARM SECTOR BECOMES FURTHER ESTABLISHED TDA. TEMPS FCST IS COMPLEX
TDA AMID VARIABLE CLOUD COVER TDA. GIVEN THE MID MARCH SUN
ANGLE...THERE IS A POTENTIAL FOR STRATUS TO TAKE LONGER TO MIX OUT
THAN MODELS FCST ESPECIALLY TOWARD THE CHSPK BAY. HAVE CUT DOWN MAX
TEMPS SEVERAL DEGREES FROM BIAS-CORRECTED MET. ELSEWHERE...HI CLOUDS
THIS MRNG WILL THICKEN/LOWER THRUOUT THE DAY AS LLVL ISENTROPIC LIFT
DEVELOPS AHEAD OF THE COLD FRONT. HIRES MODEL GUIDANCE IN AGREEMENT
WITH FRONTAL BAND OF PRECIP REMAINING WEST OF THE CWA TDA...BUT A
FEW LGT SHOWERS MAY DEVELOPS OVER THE POTOMAC HIGHLANDS LATE THIS
AFTN.
00Z NAM/GFS IN GOOD AGREEMENT WITH THE COLD FRONT CROSSING THE
CENTRAL APPALACHIANS CLOSE TO MIDNIGHT. STEADIER SHOWERS SHOULD MOVE
INTO THE MTS THIS EVE WHILE LIGHTER AND MORE SCATTERED ACTIVITY
DEVELOPS EAST OF THE BLUE RIDGE. COLD FRONT IS EXPECTED TO CROSS THE
BLUE RIDGE OVNGT WHILE WIDESPREAD SHOWERS SPREAD EWD. WENT WARM WITH
MIN TEMPS TNGT AS SLY FLOW AHEAD OF THE FRONT PREVENTS TEMPS FROM
DROPPING MUCH DURING THE NGT.
&&
.SHORT TERM /TUESDAY/...
COLD FRONT WILL MOVE ACROSS THE CWA TUESDAY...DURING THE MORNING
WEST OF THE BLUE RIDGE AND THEN MIDDAY/EARLY AFTERNOON TOWARD THE
INTERSTATE 95 CORRIDOR. PREFER A NAM/SREF TIMING FOR FROPA/PRECIP
ALTHOUGH GFS/ECMWF AREN/T MUCH DIFFERENT. THIS SHOULD ALLOW SHOWERS
TO TAPER OFF ACROSS THE INTERSTATE 95 CORRIDOR BY EARLY AFTERNOON.
TOTAL RAINFALL LOOKS TO BE ON THE ORDER OF 1/2 TO 3/4 OF AN INCH
ACROSS THE CWA.
IF SHOWERS END AS FORECAST AND PARTIAL CLEARING OCCURS LATER IN THE
AFTERNOON...THEN MAXIMA SHOULD BE ABLE TO RECOVER AOA 60 DEG F
ACROSS MUCH OF THE CWA /SAVE FOR HIGHER ELEVATIONS/. WITH THIS
EXPECTATION AND CONSIDERING RECENT COLD BIASES FROM
GUIDANCE...FAVORED THE WARMER BIAS CORRECTED MAV FOR MAXIMA ON
TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
UPPER TROUGH/SHORTWAVE AND ASSOCIATED REINFORCING FRONT AT THE
SURFACE MOVE THROUGH ON WEDNESDAY. THIS MAY PROMOTE LIGHT
PRECIPITATION ACROSS THE NORTHWEST PORTION OF THE CWA...AND ALSO IS
LIKELY TO BRING MOSTLY CLOUDY AND BLUSTERY CONDITIONS ACROSS THE
CWA.
COOLER AIR WILL MOVE IN BEHIND TUESDAY/S FROPA FOR WEDNESDAY...BUT
COLDEST PERIOD OF THE STRETCH LOOKS TO BE THURSDAY/THURSDAY NIGHT IN
THE WAKE OF THE REINFORCING BOUNDARY.
MID-ATLANTIC REMAINS IN A WEST/NORTHWEST FLOW ALOFT INTO THE
WEEKEND. BOTH GFS AND ECMWF INDICATE A WAVE BRINGING A CHANCE OF
PRECIP SOMETIME IN THE SATURDAY THROUGH SUNDAY TIME FRAME. IT/S A
LOW CONFIDENCE FORECAST ATTM AND CONTINUE LOW POPS FOR MAINLY SHRA
DURING THE DAY AND SHSN AT NIGHT.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
STRATUS DECK CONTINUES TO ADVECT INLAND ERY THIS MRNG...RESULTING IN
IFR CIGS. LATEST OBS AND 11U-3.9U SAT IMAGERY SHOWS STRATUS DECK HAS
ADVANCED WESTWARD TO ABOUT DCA AS OF 0730Z. FCST REGARDING INLAND
PROGRESSION OF STRATUS DECK ERY THIS MRNG WAS IN BETWEEN THE HRRR
AND NAM /BOTH CAPTURED THIS STRATUS EVENT WELL THUS FAR/ WHICH
REACHES IAD BEFORE SUNRISE BUT STAYS EAST OF MRB AND CHO. THE HRRR
DEVELOPS STRATUS AS FAR WEST AS IAD TO FDK TO EZF WHILE THE 00Z NAM
TAKES IT AS FAR INLAND AS MRB BY SUNRISE.
06Z TAFS REFLECTS EROSION OF STRATUS DECK FROM WEST TO EAST DURING
THE MRNG. GIVEN THE MARCH SUN ANGLE...STRATUS MAY BE MORE STUBBORN
TO ERODE THAN MODELS INDICATE. BWI AND MTN ARE MOST PRONE TO STRATUS
HANGING UNTIL MIDDAY...AND POSSIBLY EVEN LATER.
SHOWERS WILL OVERSPREAD THE TERMINALS FROM WEST TO EAST TNGT.
SHOWERS AND CIG/VSBY RESTRICTIONS MAY DEVELOP BEFORE MIDNIGHT AT
MRB/CHO AND OVNGT FARTHER EAST. LLWS ADDED TO TAFS FOR OVNGT AS 50
KT LOW-LEVEL JET CROSSES TERMINALS.
GUIDANCE SUGGESTS IFR CONDITIONS ONGOING AT THE START OF TUESDAY.
FLIGHT RESTRICTIONS WILL ASSOCIATED WITH SHOWERS MOVING THROUGH
DURING THE MORNING PUSH. FROPA THAT BRINGS THE SHOWERS LOOKS TO
OCCUR DURING MIDDAY/EARLY AFTERNOON HOURS AT THE HUBS...WITH A WIND
SHIFT TO THE NORTHWEST. THIS SHOULD ALSO PROMOTE IMPROVING
CONDITIONS TO VFR FOR THE AFTERNOON. REINFORCING COLD FRONT MOVES
THROUGH ON WEDNESDAY WITH THE POTENTIAL FOR GUSTY WINDS.
&&
.MARINE...
SELY WINDS INCREASE THIS MRNG WHILE HIPRES MOVES OFFSHORE. WINDS
BECOME MORE SLY THIS AFTN AND TNGT AS A COLD FRONT APPROACHES FROM
THE WEST. SCA STARTS LATE THIS AFTN FOR THE MAIN STEM OF THE MD
CHSPK BAY AND LOWER TIDAL POTOMAC RVR...WHICH ARE MOST PRONE TO SLY
CHANNELING. SCA IN EFFECT FOR ALL WATERS TNGT.
SCA HAS BEEN EXTENDED OVER THE MD CHESAPEAKE BAY AND LOWER TIDAL
POTOMAC RIVER TUESDAY MORNING FOR ONGOING GUSTY/CHANNELLING
SOUTHERLY FLOW. COLD FRONT MOVES EAST OF THE BAY DURING THE EARLY
AFTERNOON HOURS...WITH A WIND SHIFT TO THE NORTHWEST. REINFORCING
FRONT MOVES THROUGH WEDNESDAY...WITH SCA CONDITIONS LIKELY TO
RETURN.
&&
.TIDES/COASTAL FLOODING...
WITH PERSISTENT SELY FLOW...ANOMALIES REMAIN AT OR JUST BELOW 2 FT
THIS MRNG. ANOMALIES MAY INCREASE A BIT MORE TDA WITH SELY FLOW
EXPECTED TO INCREASE. IF ANOMALIES DO INCREASE A BIT MORE...THAN
ANNAPOLIS WOULD APPROACH MODERATE FLOOD STAGE. A COASTAL FLOOD
WARNING FOR ANNE ARUNDEL COUNTY IS IN EFFECT THRU THIS EVE
ACCORDINGLY. A COASTAL FLOOD ADVISORY WILL CONTINUE INTO TDA ALONG
THE REMAINDER OF THE WRN SHORE OF THE MD CHSPK BAY AND THE TIDAL
POTOMAC RVR.
WILL LIKE TO MONITOR HOW ANOMALIES RESPOND TDA BEFORE EXTENDING THE
WRNG OR ISSUING A WATCH FOR ANNE ARUNDEL SINCE CONFIDENCE IN
REACHING MODERATE THRESHOLD IS TOO LOW TO ISSUE ATTM. CONFIDENT
ON ADVISORY LEVEL /MINOR/ FLOODING CONTINUING INTO TUESDAY.
COLD FRONT MOVES THROUGH THE BAY BY EARLY AFTERNOON TUESDAY.
NORTHWEST WINDS BEHIND THE FRONT SHOULD HELP TO BRING LOWER WATER
LEVELS THEREAFTER...HOWEVER HOW QUICKLY WATER LEVELS LOWER WILL
DETERMINE WHETHER OR NOT ADVISORIES MAY CONTINUE FOR THE
SUBSEQUENT HIGH TIDE CYCLE LATER TUESDAY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR DCZ001.
MD...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR MDZ007-
011-013-016>018.
COASTAL FLOOD WARNING UNTIL MIDNIGHT EDT TONIGHT FOR MDZ014.
VA...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR
VAZ052>055-057.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 1 PM EDT
TUESDAY FOR ANZ530-531-538>541.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 1 PM EDT
TUESDAY FOR ANZ532>534-537-542-543.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 5 AM EDT
TUESDAY FOR ANZ535.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 5 AM EDT
TUESDAY FOR ANZ536.
&&
$$
SYNOPSIS...JRK/BPP
NEAR TERM...JRK
SHORT TERM...BPP
LONG TERM...BPP
AVIATION...JRK/BPP
MARINE...JRK/BPP
TIDES/COASTAL FLOODING...JRK/BPP
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
422 AM EDT MON MAR 11 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY MOVE ACROSS THE MIDWEST TODAY. EXPECT
RAIN TO OVERSPREAD THE REGION LATE TODAY AND TONIGHT. BELOW
NORMAL TEMPERATURES WILL RETURN BY WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AREA OF SPRINKLES...ASSOCIATED WITH SHORTWAVE OVER CENTRAL
OHIO...IS MOVING NORTHWARD TOWARD LAKE ERIE. LATEST MODEL DATA
KEEPS THIS SHORTWAVE TO THE NORTH AND WEST FOLLOWING THE STRONG
SOUTHERLY FLOW ALOFT.
BROAD AREA OF HIGH CLOUDS WILL COVER THE AREA THROUGH THE MORNING
HOURS. CLOUDS WILL LOWER THIS AFTERNOON FROM THE WEST...AS SLOW
MOVING FRONT APPROACHES. ABOVE AVE CONFIDENCE ON SLOWER FORECAST
TODAY. LATEST HIRES MODELS ARE IN GOOD AGREEMENT WITH OP MODELS
THAT MAIN AREA OF RAIN WILL SLOWLY MOVE THROUGH THE WEST LATE THIS
MORNING AND THROUGH THE AFTERNOON AND WILL NOT REACH THE EASTERN
HALF UNTIL THIS EVE. AN ISO SHOWER OR SPRINKLES IS POSSIBLE AHEAD
OF THE MAIN AREA.
WITH AREA IN THE WARM SECTOR...TEMPS WILL RISE ABOVE NORMAL AGAIN
TODAY. LAMP MODEL HAS DONE PRETTY WELL WITH WARM AIR MASS...SO
WILL LEAN ON THAT FOR HIGHS TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
EXPTG SHRA WITH FROPA OVRNGT. COLD AIR ADVCTN WL BEGIN AFT FROPA
WITH LOW CHCS FOR PCPN. CRITICAL THICKNESSES/PROFILES INDICATE
SHRA MAY MIX WITH SHSN TUE. HIGH TEMPS ARE EXPD TO DROP BLO
SEASONAL AVGS AGAIN TUE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
COLD NW FLOW AND AN UPR LVL TROF WL BRING INCRG SHSN CHCS TO THE
RGN THRU WED. SFC HI PRES GRDLY BLDS IN THU AND THU NGT. A WK SFC
LOW IS EXPD TO QUICKLY TRACK SEWD ACRS THE OH VLY RGN FRI...WITH A
CHC FOR SHRA/SHSN MAINLY S OF PIT. A QUASI STNRY FNT IS EXPD TO
SET UP ACRS THE OH/TN VLY RGNS OVR THE WK END...CONTG THE CHC FOR
SHRA/SHSN MAINLY S OF PIT. TEMPS EXPD TO REMAIN BLO SEASONAL AVGS
THRU THE PD.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
VFR WEA WL CONT THRU MONDAY...HOWEVER...LLWS WL BE A CONCERN LATE
TNGT AND EARLY MONDAY AS DEEPENING LOW PRES DVLPS TWD THE WRN GREAT
LAKES. LATEST NAM AND RAP MDL SNDINGS INDICATE SUFFICIENT
ENHANCEMENTMENT OF THE LLVL JET TO ADD A WIND SHEAR MENTION FOR THE
OVRNGT HRS IN ALL...BUT ERNMOST TAF SITES.
THIS STRONG WARM ADVCTN REGIME SHOULD CAP THE BNDRY LYR...AND THUS
LIMIT GUSTS ON MONDAY. 20 TO 25 KT SFC GUSTS WL SUFFICE FOR THE
CURRENT PROGNOSIS.
.OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/...
THE CDFNT EXTENDING FM THE AFOREMENTIONED GREAT LAKES LOW IS
FORECAST FOR A MONDAY NGT CROSSING OF THE UPR OH VALLEY.
RESTRICTIONS IN SHRA SHOULD BE ANTICIPATED WITH THAT PASSAGE...AND
IN THE COLD ADVCTN REGIME BEHIND A REINFORCING FRONT PROJECTED FOR
TUESDAY.
HIGH PRES IS EXPECTED TO RTN GENL VFR TO REGIONAL PORTS FOR LTR
THURSDAY AND FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
401 AM EDT MON MAR 11 2013
.SYNOPSIS...
HIGH PRESSURE WILL RESIDE ALONG THE MID-ATLANTIC COAST TODAY. A
COLD FRONT WILL APPROACH TONIGHT...AND THEN MOVE ACROSS THE AREA
DURING THE MORNING AND EARLY AFTERNOON ON TUESDAY. AN UPPER TROUGH
IS EXPECTED TO LINGER OVER THE NORTHEASTERN QUARTER OF THE COUNTRY
THROUGH THE END OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
A LGT SE RETURN FLOW HAS DEVELOPED IN RESPONSE TO HIPRES SHIFTING
OFF THE ERN SEABOARD. ONSHORE COMPONENT TO THE FLOW HAS ADVECTED
MARINE LAYER INLAND ERY THIS MRNG. 11U-3.9U SAT IMAGERY SHOWS
STRATUS DECK HAS ADVANCED WESTWARD TO ABOUT I-95 AT 07Z. FCST
REGARDING INLAND PROGRESSION OF STRATUS DECK ERY THIS MRNG WAS IN
BETWEEN THE HRRR AND NAM...WHICH HAVE BOTH CAPTURED THIS STRATUS
EVENT WELL THUS FAR. THE HRRR DEVELOPS STRATUS AS FAR WEST AS IAD TO
FDK TO EZF WHILE THE 00Z NAM TAKES IT AS FAR INLAND AS MRB BY
SUNRISE.
LOPRES WILL TRACK NEWD ACROSS THE UPPER MIDWEST TDA WHILE ATTENDANT
COLD FRONT MOVES THRU THE OH VLY. DEEP SLY FLOW WITHIN PRE-FRONTAL
WARM SECTOR BECOMES FURTHER ESTABLISHED TDA. TEMPS FCST IS COMPLEX
TDA AMID VARIABLE CLOUD COVER TDA. GIVEN THE MID MARCH SUN
ANGLE...THERE IS A POTENTIAL FOR STRATUS TO TAKE LONGER TO MIX OUT
THAN MODELS FCST ESPECIALLY TOWARD THE CHSPK BAY. HAVE CUT DOWN MAX
TEMPS SEVERAL DEGREES FROM BIAS-CORRECTED MET. ELSEWHERE...HI CLOUDS
THIS MRNG WILL THICKEN/LOWER THRUOUT THE DAY AS LLVL ISENTROPIC LIFT
DEVELOPS AHEAD OF THE COLD FRONT. HIRES MODEL GUIDANCE IN AGREEMENT
WITH FRONTAL BAND OF PRECIP REMAINING WEST OF THE CWA TDA...BUT A
FEW LGT SHOWERS MAY DEVELOPS OVER THE POTOMAC HIGHLANDS LATE THIS
AFTN.
00Z NAM/GFS IN GOOD AGREEMENT WITH THE COLD FRONT CROSSING THE
CENTRAL APPALACHIANS CLOSE TO MIDNIGHT. STEADIER SHOWERS SHOULD MOVE
INTO THE MTS THIS EVE WHILE LIGHTER AND MORE SCATTERED ACTIVITY
DEVELOPS EAST OF THE BLUE RIDGE. COLD FRONT IS EXPECTED TO CROSS THE
BLUE RIDGE OVNGT WHILE WIDESPREAD SHOWERS SPREAD EWD. WENT WARM WITH
MIN TEMPS TNGT AS SLY FLOW AHEAD OF THE FRONT PREVENTS TEMPS FROM
DROPPING MUCH DURING THE NGT.
&&
.SHORT TERM /TUESDAY/...
COLD FRONT WILL MOVE ACROSS THE CWA TUESDAY...DURING THE MORNING
WEST OF THE BLUE RIDGE AND THEN MIDDAY/EARLY AFTERNOON TOWARD THE
INTERSTATE 95 CORRIDOR. PREFER A NAM/SREF TIMING FOR FROPA/PRECIP
ALTHOUGH GFS/ECMWF AREN/T MUCH DIFFERENT. THIS SHOULD ALLOW SHOWERS
TO TAPER OFF ACROSS THE INTERSTATE 95 CORRIDOR BY EARLY AFTERNOON.
TOTAL RAINFALL LOOKS TO BE ON THE ORDER OF 1/2 TO 3/4 OF AN INCH
ACROSS THE CWA.
IF SHOWERS END AS FORECAST AND PARTIAL CLEARING OCCURS LATER IN THE
AFTERNOON...THEN MAXIMA SHOULD BE ABLE TO RECOVER AOA 60 DEG F
ACROSS MUCH OF THE CWA /SAVE FOR HIGHER ELEVATIONS/. WITH THIS
EXPECTATION AND CONSIDERING RECENT COLD BIASES FROM
GUIDANCE...FAVORED THE WARMER BIAS CORRECTED MAV FOR MAXIMA ON
TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
UPPER TROUGH/SHORTWAVE AND ASSOCIATED REINFORCING FRONT AT THE
SURFACE MOVE THROUGH ON WEDNESDAY. THIS MAY PROMOTE LIGHT
PRECIPITATION ACROSS THE NORTHWEST PORTION OF THE CWA...AND ALSO IS
LIKELY TO BRING MOSTLY CLOUDY AND BLUSTERY CONDITIONS ACROSS THE
CWA.
COOLER AIR WILL MOVE IN BEHIND TUESDAY/S FROPA FOR WEDNESDAY...BUT
COLDEST PERIOD OF THE STRETCH LOOKS TO BE THURSDAY/THURSDAY NIGHT IN
THE WAKE OF THE REINFORCING BOUNDARY.
MID-ATLANTIC REMAINS IN A WEST/NORTHWEST FLOW ALOFT INTO THE
WEEKEND. BOTH GFS AND ECMWF INDICATE A WAVE BRINGING A CHANCE OF
PRECIP SOMETIME IN THE SATURDAY THROUGH SUNDAY TIME FRAME. IT/S A
LOW CONFIDENCE FORECAST ATTM AND CONTINUE LOW POPS FOR MAINLY SHRA
DURING THE DAY AND SHSN AT NIGHT.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
STRATUS DECK CONTINUES TO ADVECT INLAND ERY THIS MRNG...RESULTING IN
IFR CIGS. LATEST OBS AND 11U-3.9U SAT IMAGERY SHOWS STRATUS DECK HAS
ADVANCED WESTWARD TO ABOUT DCA AS OF 0730Z. FCST REGARDING INLAND
PROGRESSION OF STRATUS DECK ERY THIS MRNG WAS IN BETWEEN THE HRRR
AND NAM /BOTH CAPTURED THIS STRATUS EVENT WELL THUS FAR/ WHICH
REACHES IAD BEFORE SUNRISE BUT STAYS EAST OF MRB AND CHO. THE HRRR
DEVELOPS STRATUS AS FAR WEST AS IAD TO FDK TO EZF WHILE THE 00Z NAM
TAKES IT AS FAR INLAND AS MRB BY SUNRISE.
06Z TAFS REFLECTS EROSION OF STRATUS DECK FROM WEST TO EAST DURING
THE MRNG. GIVEN THE MARCH SUN ANGLE...STRATUS MAY BE MORE STUBBORN
TO ERODE THAN MODELS INDICATE. BWI AND MTN ARE MOST PRONE TO STRATUS
HANGING UNTIL MIDDAY...AND POSSIBLY EVEN LATER.
SHOWERS WILL OVERSPREAD THE TERMINALS FROM WEST TO EAST TNGT.
SHOWERS AND CIG/VSBY RESTRICTIONS MAY DEVELOP BEFORE MIDNIGHT AT
MRB/CHO AND OVNGT FARTHER EAST. LLWS ADDED TO TAFS FOR OVNGT AS 50
KT LOW-LEVEL JET CROSSES TERMINALS.
GUIDANCE SUGGESTS IFR CONDITIONS ONGOING AT THE START OF TUESDAY.
FLIGHT RESTRICTIONS WILL ASSOCIATED WITH SHOWERS MOVING THROUGH
DURING THE MORNING PUSH. FROPA THAT BRINGS THE SHOWERS LOOKS TO
OCCUR DURING MIDDAY/EARLY AFTERNOON HOURS AT THE HUBS...WITH A WIND
SHIFT TO THE NORTHWEST. THIS SHOULD ALSO PROMOTE IMPROVING
CONDITIONS TO VFR FOR THE AFTERNOON. REINFORCING COLD FRONT MOVES
THROUGH ON WEDNESDAY WITH THE POTENTIAL FOR GUSTY WINDS.
&&
.MARINE...
SELY WINDS INCREASE THIS MRNG WHILE HIPRES MOVES OFFSHORE. WINDS
BECOME MORE SLY THIS AFTN AND TNGT AS A COLD FRONT APPROACHES FROM
THE WEST. SCA STARTS LATE THIS AFTN FOR THE MAIN STEM OF THE MD
CHSPK BAY AND LOWER TIDAL POTOMAC RVR...WHICH ARE MOST PRONE TO SLY
CHANNELING. SCA IN EFFECT FOR ALL WATERS TNGT.
SCA HAS BEEN EXTENDED OVER THE MD CHESAPEAKE BAY AND LOWER TIDAL
POTOMAC RIVER TUESDAY MORNING FOR ONGOING GUSTY/CHANNELLING
SOUTHERLY FLOW. COLD FRONT MOVES EAST OF THE BAY DURING THE EARLY
AFTERNOON HOURS...WITH A WIND SHIFT TO THE NORTHWEST. REINFORCING
FRONT MOVES THROUGH WEDNESDAY...WITH SCA CONDITIONS LIKELY TO
RETURN.
&&
.TIDES/COASTAL FLOODING...
WITH PERSISTENT SELY FLOW...ANOMALIES REMAIN AT OR JUST BELOW 2 FT
THIS MRNG. ANOMALIES MAY INCREASE A BIT MORE TDA WITH SELY FLOW
EXPECTED TO INCREASE. IF ANOMALIES DO INCREASE A BIT MORE...THAN
ANNAPOLIS WOULD APPROACH MODERATE FLOOD STAGE. A COASTAL FLOOD
WARNING FOR ANNE ARUNDEL COUNTY IS IN EFFECT THRU THIS EVE
ACCORDINGLY. A COASTAL FLOOD ADVISORY WILL CONTINUE INTO TDA ALONG
THE REMAINDER OF THE WRN SHORE OF THE MD CHSPK BAY AND THE TIDAL
POTOMAC RVR.
WILL LIKE TO MONITOR HOW ANOMALIES RESPOND TDA BEFORE EXTENDING THE
WRNG OR ISSUING A WATCH FOR ANNE ARUNDEL SINCE CONFIDENCE IN
REACHING MODERATE THRESHOLD IS TOO LOW TO ISSUE ATTM.
CONFIDENT ON ADVISORY LEVEL /MINOR/ FLOODING CONTINUING INTO TUESDAY.
NW FLOW BHD FNT SHUD ALLEVIATE CSTL FLOOD CONCERNS...BUT WE WL
SEE HOW QUICKLY THAT WL FOLLOW.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR DCZ001.
MD...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR MDZ007-
011-013-016>018.
COASTAL FLOOD WARNING UNTIL MIDNIGHT EDT TONIGHT FOR MDZ014.
VA...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR
VAZ052>055-057.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 1 PM EDT
TUESDAY FOR ANZ530-531-538>541.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 1 PM EDT
TUESDAY FOR ANZ532>534-537-542-543.
SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 5 AM EDT
TUESDAY FOR ANZ535.
SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 5 AM EDT
TUESDAY FOR ANZ536.
&&
$$
SYNOPSIS...JRK/BPP
NEAR TERM...JRK
SHORT TERM...BPP
LONG TERM...BPP
AVIATION...JRK/BPP
MARINE...JRK/BPP
TIDES/COASTAL FLOODING...JRK/BPP/HTS
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
138 AM EDT MON MAR 11 2013
.SYNOPSIS...
A COLD FRONT WILL SLOWLY MOVE ACROSS THE MIDWEST TODAY. EXPECT
RAIN TO OVERSPREAD THE REGION LATE TODAY AND TONIGHT. BELOW
AVERAGE TEMPERATURES WILL RETURN BY WEDNESDAY.
&&
.NEAR TERM /THROUGH TODAY/...
LITTLE CHANGE TO OVERNIGHT. MADE MINOR ADJUSTMENTS TO TEMPS AND
CLOUD COVER.
MODELS ARE IN GOOD AGREEMENT SLOWLY THE ONSET OF RAIN TODAY. WILL
HOLD OF THE MENTION IN THE WESTERN HALF UNTIL THE AFTERNOON...WITH
RAIN NOT REACHING THE EASTERN HALF UNTIL THIS EVE.
EXPECT ANOTHER DAY OF ABOVE NORMAL TEMPS WITH SOUTHERLY WINDS
STRENGTHENING AHEAD OF THE SFC FRONT.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
EXPTG SHRA WITH FROPA OVRNGT. COLD AIR ADVCTN WL BEGIN AFT FROPA
WITH LOW CHCS FOR PCPN. CRITICAL THICKNESSES/PROFILES INDICATE
SHRA MAY MIX WITH SHSN TUE. HIGH TEMPS ARE EXPD TO DROP BLO
SEASONAL AVGS AGAIN TUE.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
COLD NW FLOW AND AN UPR LVL TROF WL BRING INCRG SHSN CHCS TO THE
RGN THRU WED. SFC HI PRES GRDLY BLDS IN THU AND THU NGT. A WK SFC
LOW IS EXPD TO QUICKLY TRACK SEWD ACRS THE OH VLY RGN FRI...WITH A
CHC FOR SHRA/SHSN MAINLY S OF PIT. A QUASI STNRY FNT IS EXPD TO
SET UP ACRS THE OH/TN VLY RGNS OVR THE WK END...CONTG THE CHC FOR
SHRA/SHSN MAINLY S OF PIT. TEMPS EXPD TO REMAIN BLO SEASONAL AVGS
THRU THE PD.
&&
.AVIATION /05Z MONDAY THROUGH FRIDAY/...
VFR WEA WL CONT THRU MONDAY...HOWEVER...LLWS WL BE A CONCERN LATE
TNGT AND EARLY MONDAY AS DEEPENING LOW PRES DVLPS TWD THE WRN GREAT
LAKES. LATEST NAM AND RAP MDL SNDINGS INDICATE SUFFICIENT
ENHANCEMENTMENT OF THE LLVL JET TO ADD A WIND SHEAR MENTION FOR THE
OVRNGT HRS IN ALL...BUT ERNMOST TAF SITES.
THIS STRONG WARM ADVCTN REGIME SHOULD CAP THE BNDRY LYR...AND THUS
LIMIT GUSTS ON MONDAY. 20 TO 25 KT SFC GUSTS WL SUFFICE FOR THE
CURRENT PROGNOSIS.
.OUTLOOK.../MONDAY NIGHT THROUGH FRIDAY/...
THE CDFNT EXTENDING FM THE AFOREMENTIONED GREAT LAKES LOW IS
FORECAST FOR A MONDAY NGT CROSSING OF THE UPR OH VALLEY.
RESTRICTIONS IN SHRA SHOULD BE ANTICIPATED WITH THAT PASSAGE...AND
IN THE COLD ADVCTN REGIME BEHIND A REINFORCING FRONT PROJECTED FOR
TUESDAY.
HIGH PRES IS EXPECTED TO RTN GENL VFR TO REGIONAL PORTS FOR LTR
THURSDAY AND FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
331 AM CDT MON MAR 11 2013
.DISCUSSION...
WILL SEE A GOOD COOLDOWN FOR THE START OF THE WEEK BEHIND
SHORTWAVE CURRENTLY DROPPING SOUTHEAST THROUGH SASKATCHEWAN. THAT
FEATURE HELPS CARVE OUT A NICE TROUGH FROM OUR AREA THROUGH THE
GREAT LAKES REGION BY TUESDAY... WITH CYCLONIC FLOW AND BELOW
NORMAL TEMPERATURES LIKELY BRINGING SOME SNOW SHOWER ACTIVITY
GIVEN THE EASE WITH WHICH WE CAN GENERATE STEEP LOW LEVEL LAPSE
RATES NOW. AFTER THAT... THE LARGE SCALE PATTERN LOOKS TO MODERATE
OVER THE SECOND HALF OF THE WEEK... WITH NORTHWEST FLOW GIVING WAY
TO MORE IN THE WAY OF RIDGING AND WESTERLY DOWNSLOPING FLOW FROM
THE ROCKIES. THAT COULD BRING SOME CHANCES FOR MIXED PCPN DURING
THE END OF THE WEEK INTO THE WEEKEND... ALTHOUGH THERE CERTAINLY
DON/T APPEAR TO BE ANY SIGNIFICANT SYSTEMS ON THE HORIZON. FOR
SIGNIFICANCE... ATTENTION IS STILL SOMEWHAT FIXED ON THE SHORT
TERM... ALTHOUGH THAT IS BECOMING LESS INTERESTING AS WELL. RADAR
TRENDS OVER THE PAST FEW HOURS HAVE DIMINISHED MARKEDLY AS UPPER
RIDGING ENCROACHES FROM THE WEST AND THE UPPER WAVE TO OUR SOUTH
HAS SHEARED OUT AND OPENED UP A BIT. THE HIGH RESOLUTION
GUIDANCE... INCLUDING THE HRRR... LOCAL WRF-ARW... AND THE
HOPWRF... ALL DID A NICE JOB OF SHOWING THE RAPID WEAKENING
TREND... AND GENERALLY AGREE THAT ANY SIGNIFICANT PCPN IS DONE FOR
THE AREA. HOWEVER... A NARROW BAND WILL LIKELY HANG ON INTO THE
MORNING HOURS FROM FAR SOUTHEAST MINNESOTA THROUGH OUR FAR EASTERN
COUNTIES. THE AFOREMENTIONED HIGH RESOLUTION SOLUTIONS ALSO
SUGGEST A SLIGHT REJUVENATION OF ACTIVITY IN THAT AREA IN THE
12-15Z TIME FRAME... SO LOCATIONS FROM NEAR EAU CLAIRE SOUTH AND
EASTWARD COULD STILL SEE SOME ADDITIONAL LIGHT ACCUMULATIONS. THAT
BEING SAID... PLAN TO DROP MOST OF THE HEADLINES BY 09Z... LEAVING
ONLY THINGS OVER THE FAR EAST.
COULD SEE SOME FLURRIES OR SNOW SHOWERS LINGER OVER PORTIONS OF
THE AREA TONIGHT... MAINLY THE NORTH HALF... WHERE CYCLONIC FLOW
WILL LINGER AND THE SECONDARY SHORTWAVE AND TROUGH WILL ARRIVE
LATE TONIGHT. THAT FEATURE WILL HELP KEEP CYCLONIC BOUNDARY LAYER
FLOW IN PLACE THROUGH THE DAY ON TUESDAY AND GIVEN THE SHARPLY
COOLER TEMPERATURES ALOFT THAT IT BRINGS INTO THE AREA... THINK WE
SHOULD SEE A FAIR AMOUNT OF SCATTERED SNOW SHOWER ACTIVITY DURING
THE DAY ON TUESDAY. THINGS THEN LOOK TO BE FAIRLY QUIET THROUGH
WEDNESDAY... WITH THE NEXT CHANCE OF PCPN HOLDING OFF UNTIL
THURSDAY WHEN WE SEE RETURN FLOW AND DECENT WARM ADVECTION SETUP
ACROSS THE REGION. AT THIS POINT IT LOOKS LIKE THE EASTERN AND
NORTHERN FORECAST AREA HAVE THE BEST SHOT AT SEEING ANY OF THIS
WARM ADVECTION PCPN GIVEN WHERE THINGS APPEAR TO SATURATE ALONG
THE ISENTROPIC SURFACES. ANY PCPN ON THURSDAY SHOULD STILL BE IN
THE FORM OF SNOW. A BETTER SHOT AT SEEING SOME PCPN ACROSS THE
AREA WILL COME FROM FRIDAY INTO THE WEEKEND AS THE BAROCLINIC ZONE
SETS UP ACROSS THE AREA AND A FEW SHORTWAVES RIPPLE EAST-SOUTHEAST
ALONG IT. THE MAIN IMPULSE LOOKS TO SWING ACROSS THE AREA LATE
FRIDAY INTO EARLY SATURDAY... BUT THAT IS AROUND THE TIME WHEN THE
ECMWF AND GFS START TO EXHIBIT SIGNIFICANT DIFFERENCES IN THE
LARGE SCALE FLOW ACROSS THE CONTINENT... SO THERE IS CERTAINLY A
FAIR AMOUNT OF UNCERTAINTY AT THIS POINT. INCLUDED SOME POPS FOR
MUCH OF THE TIME FROM FRIDAY THROUGH SUNDAY... ALTHOUGH WITH THE
POSSIBILITY OF MIXED PCPN GIVEN THE FORECAST SOUNDINGS AND GENERAL
WARM ADVECTION PATTERN.
&&
.AVIATION.../06Z TAF ISSUANCE/
/ISSUED 1158 PM CDT SUN MAR 10 2013/
HEAVY SNOW WELL UNDER WAY FROM SOUTH CENTRAL MN UP INTO WRN WI.
HOWEVER...ONLY EAU WILL HAVE TO DEAL WITH THE BRUNT OF THE SNOW...
WITH SNOW BAND MAKING IT NO FURTHER THAN ABOUT 5-10 MILES FROM
MSP. BASED ON RAP/NAM HOURLY SNOWFALL FORECASTS...HEAVIEST SNOW
HAPPENING NOW...WITH 1/2SM TYPE SNOW NOT LASTING MUCH PAST 7Z.
WILL HAVE TO WATCH FOR A SECOND BAND OF HEAVIER SNOW FROM ABOUT
12Z TO 15Z AS MAIN UPPER LOW MOVES INTO CENTRAL WI. THE HRRR HAS
BEEN BACK AND FORTH WITH WHERE THIS BAND SETS UP BETWEEN EAU AND
BCK...SO JUST LEFT GENERAL MVFR VIS -SN DURING THE MORNING...BUT
DEPENDING ON WHERE THIS SECOND BAND SETS UP...THERE COULD BE
ANOTHER BOUT OF IFR OR LOWER VIS THERE. EVERYWHERE ELSE IT IS A
CIG PROBLEM. AXN HAS FOUND ITSELF JUST WEST OF THE LOW CLOUDS AND
IT SHOULD STAY THERE THROUGH MONDAY AFTERNOON. FOR OTHER
TERMINALS...HEIGHTS SHOULD BE FAIRLY CONSTANT THROUGH THE NIGHT.
SHOULD SEE SOME BREAKS BY MORNING...WITH CATEGORICAL IMPROVEMENTS
IN CIGS ACROSS MN BY THE AFTERNOON...BUT THERE IS THE POSSIBILITY
THAT ERN MN REMAINS IN MVFR CIGS THROUGH THE DURATION OF THE TAF
PERIOD. TOWARD THE END OF THE TAF PERIOD...STRONG WAVE CURRENTLY
UP IN ALBERTA WILL DIVE SE INTO MN ON NW FLOW. THIS WILL BRING
MVFR CIGS BACK TO WRN MN AFTER 00Z AND THEY WILL BE CLOSE TO
AXN/RWF BY THE END OF THIS TAF PERIOD.
KMSP...CONFIDENCE IS HIGH THAT FIELD REMAINS IN THE FRONT ROW
SEATS WITH ONGOING SNOW STORM JUST TO THE SE. FLIGHTS ON APPROACH
FOR THE 12S WILL LIKELY BE COMING THROUGH SNOW ON THEIR WAY
IN...BUT NOT EXPECTING ANYTHING WORSE THAN A FEW FLURRIES FOR THE
FIELD. CIGS WILL BE FLIRTING WITH 017 THROUGH THE REST OF
TONIGHT...BUT THEY SHOULD REMAIN ABOVE THIS LEVEL. CONFIDENCE IS
LOW IN CLEARING TOMORROW AFTERNOON...WITH IT VERY PLAUSIBLE THAT
MVFR CIGS NEVER BECOME BETTER THAN BKN BEFORE CLOUDS FROM NW
SYSTEM SHOW UP. FOR WINDS...SPEEDS WILL BE FAIRLY CONSISTENT IN
THE 10-15 KT RANGE WITH A SLOW BACKING TOWARD THE WEST THIS
PERIOD.
/OUTLOOK FOR KMSP/
TUE...MVFR CIGS/VSBYS POSSIBLE WITH -SN. NW WIND 15G25KTS.
WED...VFR. NW WIND 5 TO 10 KTS BACKING TO SW.
THU...VFR. S WIND AROUND 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 4 AM CDT EARLY THIS MORNING FOR
FARIBAULT-FREEBORN-GOODHUE-STEELE-WASECA.
WINTER WEATHER ADVISORY UNTIL 4 AM CDT EARLY THIS MORNING FOR
BLUE EARTH-MARTIN-RICE.
WI...WINTER STORM WARNING UNTIL 4 AM CDT EARLY THIS MORNING FOR DUNN-
PIERCE.
WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR CHIPPEWA-
EAU CLAIRE-PEPIN.
WINTER WEATHER ADVISORY UNTIL 10 AM CDT THIS MORNING FOR RUSK.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1158 PM CDT SUN MAR 10 2013
.UPDATE...
06Z AVIATION DISCUSSION ADDED BELOW.
&&
.PREV DISCUSSION...
/ISSUED 854 PM CDT SUN MAR 10 2013/
WINTER STORM BEGINNING TO TAKE SHAPE THIS EVENING AS SFC LOW MOVES
INTO THE QUAD CITIES. LAST FEW RUNS OF THE RAP HAVE BEEN REALLY
UNLOADING WITH HEAVY SNOW FROM CENTRAL FARIBAULT COUNTY...UP TO
OWATONNA...LAKE CITY...AND EAU CLAIRE/CHIP FALLS. WITH THE RAP AND
HRRR COMING IN A BIT FARTHER NW WITH THE HEAVIER SNOW...TACKED ON
A FEW MORE COUNTIES TO THE WARNING...WITH SLIGHTLY HIGHER AMOUNTS
EXPECTED AS WELL IN THE ALBERT LEA AND EAU CLAIRE AREAS.
CURRENT RADAR SHOWING A RATHER STRONG BAND SETTING UP FROM NEAR
THE CITY OF BLUE EARTH UP TOWARD LAKE CITY. AT TIMES HAVE SEEN
KAEL AND KTOB GO DOWN TO A HALF MILE VIS WITH THIS BAND
OVERHEAD...AND A CALL TO FARIBAULT COUNTY REVEALED 2 INCHES ALREADY
IN THE CITY OF BLUE EARTH. BASED ON THE RAP/SPC MESO
ANALYSIS...THIS LOOKS TO BE THE RESULT OF A COMBO OF FGEN AROUND
THE H85 LAYER...ALONG WITH STRONG MOISTURE TRANSPORT WITHIN THE
COLD CONVEYOR BELT TO THE NORTH OF THE SFC LOW. THIS IS HEAVIER
BAND 1 OF 2 THAT THE RAP HAS FOR SE MN...WITH TOTAL QPF FROM BLUE
EARTH...UP THROUGH DODGE CENTER...LAKE CITY...AND EAU CLAIRE
BETWEEN 0.85" AND 0.95"...WHICH RESULTS IN A FAIRLY HEALTHY REGION
OF 8 TO 10 INCHES OF SNOW.
BAND 2 MENTIONED ABOVE SETS UP JUST EAST OF THE FIRST BAND LATER
TONIGHT AND WILL PRIMARILY IMPACT THE ARX AREA. THIS BAND IS
ASSOCIATED WITH PV ADVECTION TO THE WEST OF THE MAIN PV ANOMALY
WHICH THE RAP TAKES FROM AROUND IOWA CITY UP TOWARD WAUSAU. THE
11.23 RAP HAS SLIGHTLY HIGHER QPF AMOUNTS UP AROUND 1 INCH IN THIS
AREA...WHICH WOULD INDICATE THE POTENTIAL FOR AMOUNTS OF A FOOT OR
MORE.
WHAT MAKES THIS A TRICKY SYSTEM TO FORECAST IS THE VERY TIGHT
GRADIENT IN SNOWFALL AND AMOUNTS THAT IS EXPECTED TO THE NORTHWEST
OF THE HEAVY BAND OF SNOW. FOR INSTANCE...ACROSS GOODHUE
COUNTY...LATEST UPDATE TO GRIDS HAS AROUND 8 INCHES ALONG THE
WABASHA COUNTY LINE IN THE SOUTH...WITH AMOUNTS NEAR 4 INCHES
ALONG THE DAKOTA COUNTY LINE TO THE NORTH. WITH THE SLIGHT
NORTHWESTWARD SHIFT IN THE HEAVIER SNOW AMOUNTS...THIS PULLED THE
6+ INCH AMOUNTS A LITTLE FARTHER NORTHWEST. FOR THE COUNTIES ADDED
/WASECA...STEELE...GOODHUE...PIERCE...DUNN...AND CHIPPEWA WI/...IT
IS BASICALLY THE SOUTHEAST HALF OR LESS OF THESE COUNTIES WHERE
AMOUNTS OF 6 INCHES OR MORE ARE EXPECTED. WITH THE TIGHT GRADIENT
IN SNOW...DID NOT SEE THE NEED TO ADD ANY COUNTIES TO AN ADVY. FOR
EXAMPLE...IN DAKOTA COUNTY...HAVE SNOWFALL AMOUNTS RANGING FROM A
TRACE ALONG THE HENNEPIN/RAMSEY COUNTY LINE TO NEAR 4 INCHES ALONG
THE GOODHUE COUNTY LINE. OTHER COUNTIES BORDERING THE WARNING SHOW
SIMILAR GRADIENTS...SO DID NOT ADD ANY COUNTIES TO AN ADVY. IF
ANYTHING...COUNTIES STILL IN THE ADVY WILL BE CLOSE TO WARNING
TYPE SNOWS IN THE FAR SOUTHEAST TIPS OF THOSE COUNTIES. KIND OF AN
ALL OR NOTHING SCENARIO HERE!
WILL BE SEEING SOME INTENSE SNOWFALL RATES TONIGHT ON THE ORDER OF
1 TO 2 INCHES PER HOUR AS WELL /SEE NESDIS SATELLITE PRECIP
ESTIMATE PRODUCT AND SPC MESO DISCUSSION #269/. BY MONDAY
MORNING...THE INTENSE SNOWFALL WILL START LETTING UP...WITH LIGHT
SNOW LINGERING INTO THE AFTERNOON...ESPECIALLY ACROSS WI. SNOW
WILL LIKELY CONTINUE BEYOND CURRENT END TIME OF HEADLINES...THOUGH
ACCUMULATING SNOWS SHOULD BE ALL BUT DONE BY NOON...BUT A POSSIBLE
EXTENSION IN TIME WILL NEED TO BE CONSIDERED BY LATER SHIFTS.
BEHIND THIS SYSTEM...IT WILL BE COOL THROUGH THE MIDDLE OF THE
WEEK AS HIGH PRESSURE SETTLES IN. TUESDAY LOOKS TO BE THE COLDEST
DAY NEXT WEEK. WITH THE COLD UPPER TROUGH OVERHEAD...THIS WILL
CREATE STEEP LAPSE RATES WITH DAYTIME HEATING AND LIKELY SOME
BOUTS OF SNOW SHOWERS...THOUGH NO ACCUMULATIONS ARE EXPECTED.
FOR THE SECOND HALF OF THE WEEK...A MODERATION IN TEMPERATURES BACK
TOWARD NORMAL /WHICH ARE ALREADY PUSHING 40 ON THE HIGHS/ IS
EXPECTED AS UPPER RIDGING BUILDS EAST FROM THE ROCKIES.
FOR NEXT WEEKEND AND BEYOND...THERE IS NOT MUCH CONFIDENCE IN THE
FORECAST AS THE ECMWF AND THE GFS SIT ABOUT 180 DEGS APART FROM
EACH OTHER. FOR NEXT WEEKEND INTO THE FOLLOWING WEEK...THE ECMWF
HAS THE DEEP THROUGH OVER ERN NOAM...WITH A SHARP RIDGE OVER THE
ROCKIES...WHICH OPENS THE DOOR FOR MORE MODIFIED ARCTIC AIR. THE
GFS ON THE OTHER HAND GOES RIDGING EAST AND TROUGHING WEST AND
BRINGS ANOTHER WARM WET SYSTEM INTO THE UPPER MS VALLEY AT THE END
OF NEXT WEEKEND INTO THE FOLLOWING WEEK. BASED ON PAST
PERFORMANCE...THE GFS IS LIKELY A BIT TOO AGGRESSIVE WITH BREAKING
DOWN THE WRN RIDGE NEXT WEEKEND.
&&
.AVIATION.../06Z TAF ISSUANCE/
HEAVY SNOW WELL UNDER WAY FROM SOUTH CENTRAL MN UP INTO WRN WI.
HOWEVER...ONLY EAU WILL HAVE TO DEAL WITH THE BRUNT OF THE SNOW...
WITH SNOW BAND MAKING IT NO FURTHER THAN ABOUT 5-10 MILES FROM
MSP. BASED ON RAP/NAM HOURLY SNOWFALL FORECASTS...HEAVIEST SNOW
HAPPENING NOW...WITH 1/2SM TYPE SNOW NOT LASTING MUCH PAST 7Z.
WILL HAVE TO WATCH FOR A SECOND BAND OF HEAVIER SNOW FROM ABOUT
12Z TO 15Z AS MAIN UPPER LOW MOVES INTO CENTRAL WI. THE HRRR HAS
BEEN BACK AND FORTH WITH WHERE THIS BAND SETS UP BETWEEN EAU AND
BCK...SO JUST LEFT GENERAL MVFR VIS -SN DURING THE MORNING...BUT
DEPENDING ON WHERE THIS SECOND BAND SETS UP...THERE COULD BE
ANOTHER BOUT OF IFR OR LOWER VIS THERE. EVERYWHERE ELSE IT IS A
CIG PROBLEM. AXN HAS FOUND ITSELF JUST WEST OF THE LOW CLOUDS AND
IT SHOULD STAY THERE THROUGH MONDAY AFTERNOON. FOR OTHER
TERMINALS...HEIGHTS SHOULD BE FAIRLY CONSTANT THROUGH THE NIGHT.
SHOULD SEE SOME BREAKS BY MORNING...WITH CATEGORICAL IMPROVEMENTS
IN CIGS ACROSS MN BY THE AFTERNOON...BUT THERE IS THE POSSIBILITY
THAT ERN MN REMAINS IN MVFR CIGS THROUGH THE DURATION OF THE TAF
PERIOD. TOWARD THE END OF THE TAF PERIOD...STRONG WAVE CURRENTLY
UP IN ALBERTA WILL DIVE SE INTO MN ON NW FLOW. THIS WILL BRING
MVFR CIGS BACK TO WRN MN AFTER 00Z AND THEY WILL BE CLOSE TO
AXN/RWF BY THE END OF THIS TAF PERIOD.
KMSP...CONFIDENCE IS HIGH THAT FIELD REMAINS IN THE FRONT ROW
SEATS WITH ONGOING SNOW STORM JUST TO THE SE. FLIGHTS ON APPROACH
FOR THE 12S WILL LIKELY BE COMING THROUGH SNOW ON THEIR WAY
IN...BUT NOT EXPECTING ANYTHING WORSE THAN A FEW FLURRIES FOR THE
FIELD. CIGS WILL BE FLIRTING WITH 017 THROUGH THE REST OF
TONIGHT...BUT THEY SHOULD REMAIN ABOVE THIS LEVEL. CONFIDENCE IS
LOW IN CLEARING TOMORROW AFTERNOON...WITH IT VERY PLAUSIBLE THAT
MVFR CIGS NEVER BECOME BETTER THAN BKN BEFORE CLOUDS FROM NW
SYSTEM SHOW UP. FOR WINDS...SPEEDS WILL BE FAIRLY CONSISTENT IN
THE 10-15 KT RANGE WITH A SLOW BACKING TOWARD THE WEST THIS
PERIOD.
/OUTLOOK FOR KMSP/
TUE...MVFR CIGS/VSBYS POSSIBLE WITH -SN. NW WIND 15G25KTS.
WED...VFR. NW WIND 5 TO 10 KTS BACKING TO SW.
THU...VFR. S WIND AROUND 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 7 AM CDT MONDAY FOR FARIBAULT-
FREEBORN-GOODHUE-STEELE-WASECA.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT MONDAY FOR BLUE EARTH-
MARTIN-RICE.
WI...WINTER STORM WARNING UNTIL 10 AM CDT MONDAY FOR CHIPPEWA-DUNN-
EAU CLAIRE-PEPIN-PIERCE.
WINTER WEATHER ADVISORY UNTIL 10 AM CDT MONDAY FOR RUSK.
&&
$$
MPG/MPG
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1233 PM CST SAT MAR 9 2013
.UPDATE...
ISSUED AT 1232 PM CST SAT MAR 9 2013
EARLY AFTERNOON UPDATE...SNOW REPORTS OF 3-6 INCHES ARE COMING IN
FOR SEVERAL LOCATIONS ACROSS NORTH WESTERN/CENTRAL NEBRASKA...THUS THE
MAIN DEFORMATION BAND IS BEHAVING AS IT SHOULD. OTHERWISE THE ONLY
SIGNIFICANT CHANGE TO THE ONGOING FORECAST WAS TO INCLUDE THE
MENTION OF THUNDER ACROSS FAR SOUTHEASTERN PORTIONS OF THE CWA.
STORMS HAVE ALREADY DEVELOPED...WITH CG NOTED SOUTH OF MASON CITY
OVER THE PAST HALF HOUR.
UPDATE ISSUED AT 1021 CST SAT MAR 9 2013
OVERALL IDEA OF THE FORECAST REMAINS ON TRACK WITH ONLY MINOR
REVISIONS TO FRESHEN UP WIND SPEEDS...TIMING OF THE SNOW
CHANGEOVER...AND FREEZING RAIN AMOUNTS. PHONE CALLS IN AND AROUND
KVTN THIS MORNING SUGGESTED ABOUT A TENTH OF AN INCH OF ICE OR
LESS ACCUMULATION...THUS WILL TREND DOWN THE QUARTER OF AN INCH WE
HAD GOING FOR THE CENTRAL SAND HILLS...WITH WORDING OF MINOR
ICE ACCUMULATIONS. OTHERWISE ONCE THE CHANGE OVER TO SNOW
OCCURS...SNOW RATES OF AN INCH PER HOUR HAVE BEEN NOTED UNDER THE
HEAVIEST OF BANDS. 12Z NAM APPEARS REASONABLE AT THIS
JUNCTURE...THUS TRENDED IN THAT DIRECTION. THE NARROW BAND OF QPF
WILL CONTINUE THROUGH MID AFTERNOON ACROSS NORTHWEST NEBRASKA
ALONG A STRONG BAND OF H7 FRONTOGENESIS AND WITH AID FROM THE LFQ
OF A 90KT JET. SNOW ACCUMULATIONS OF 6 INCHES OR GREATER STILL
APPEARS LIKELY ACROSS NORTHWEST NEBRASKA. BUT LATER TODAY...SNOW
WILL BEGIN TO TAPER OFF BY LATE AFTERNOON AS THE NORTHERN STREAM
RACES SOUTHEAST ACROSS THE NORTHERN PLAINS AND ALLOWS FOR THE
INTRUSION OF DRIER AIR INTO THE NORTHERN REACHES OF THE CWA.
HOWEVER ALL NEAR TERM SOLUTIONS DO INDICATE THE FORMATION OF A
SECOND AREA OF DEFORMATION ACROSS FAR SOUTHEASTERN PORTIONS OF THE
FORECAST AREA...ALIGNED NORTHEAST TO SOUTHWEST WITH THE EASTWARD
ADVANCING MID LEVEL FRONTOGENETIC FORCING...FORECAST FOR THIS
SECOND BAND APPEARS ON TRACK AT THIS TIME...WILL REVISIT EXPECTED
SNOW AMOUNTS AS ADDITIONAL GUIDANCE COMES IN THIS MORNING.
UPDATE ISSUED AT 700 AM CST SAT MAR 9 2013
NO NEW DATA WAS AVAILABLE FOR THE QPF FORECAST BUT INDICATIONS ARE
THE RAP13 IS VERIFYING ACROSS NRN NEB WITH OVER 1/2 INCH OF ICE AT
THE KVTN ASOS. AFTER SLOWING THE EASTERN PROGRESSION OF THE RAIN
CHANGE LINE USING THE RUC...NORTH WINDS HAVE INCREASED AND NOW THE
RAIN CHANGE LINE IS ROUGHLY FROM CHAPPELL TO THEDFORD TO AINSWORTH.
SO THE NAM MAY BE VERIFYING BETTER AND IT WAS USED IN THE NEW
FORECAST.
A NEW WIND FORECAST USING NAM...GEM...MET AND MAV GUIDANCE
PRODUCED GUSTS TO 50 MPH THIS AFTERNOON AND THIS EVENING WHICH IS
CONSISTENT WITH THE 60KT BARRIER JET FCST BY BOTH MODELS. THIS
STRUCTURE IS FCST TO SET UP ACROSS THE ERN PANHANDLE THIS MORNING
AND MOVE SLOWLY EAST THIS AFTN AND TONIGHT ACTING AS A FOCUS FOR
SNOW AND STRONG WINDS.
THERE IS NO CHANGE TO THE DYNAMICS. STRONG FRONTOGENESIS HANGS
UP ACROSS THE NORTHWEST TODAY AND DECAYS WHILE A NEW STRUCTURE
DEVELOPS FARTHER EAST THIS EVENING. THE RAP HAS COME IN LINE WITH
THE NAM AND ECM DEVELOPING THE NEW SNOW EAST OF THE FCST AREA
WHILE THE 06Z GFS HANGS IT UP ACROSS NCNTL AND SWRN NEB...VERY
TROUBLING. GIVEN THE VERY STRONG WINDS DEVELOPING...EVEN AN 1/2
INCH PER HOUR SNOWFALL RATE COULD PRODUCE BLIZZARD CONDITIONS.
THE SNOW SHOULD GRADUALLY END OVERNIGHT AND SUNDAY MORNING WEST TO
EAST WITH CLEARING SKIES TO FOLLOW. WINDY CONDITIONS CONTINUE
SUNDAY MORNING IN THE EAST.
UPDATE ISSUED AT 527 AM CST SAT MAR 9 2013
THE RAP13 MODEL SHOWS A SLOWER TRANSITION TO SNOW THAN THE NAM. IN
FACT THE RAP CARRIES A BROAD AREA OF FREEZING RAIN AHEAD OF THE
CHANGEOVER TO SNOW. THIS IS WELL SUPPORTED IN THE MODEL TEMPERATURE
FIELDS. SO A NEW FORECAST IS OUT WHICH HEIGHTENS THE THREAT OF
FREEZING RAIN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT MAR 9 2013
TWO ROUNDS OF THOUGHT WITH THE STORM. ONE IS FOR A STRONG FGEN
FORCED BAND OF SNOW DEVELOPING ACROSS NORTHWEST NEBRASKA TODAY
WHICH MOST SOLNS AGREE ON TO VARYING DEGREES. THE SECOND IS FOR
ANOTHER STRONG BAND OF SNOW TO DEVELOP ACROSS SOUTH CENTRAL
NEBRASKA TONIGHT AS THE FIRST BAND DECAYS. THE GEM REGIONAL AND
GFS ARE VERY FAR NORTHWEST WITH THIS BAND SIGNALING A WINTER
STORM FOR NCNTL NEB WHILE THE NAM AND ECM ARE SAFELY EAST OF THE
FCST AREA. A BLEND OF NAM...GEM AND ECM WERE USED FOR THE LATEST
FCST WHICH PROVIDES A WINTER STORM ACROSS THE NORTHWEST AND A
WINTER WEATHER ADVISORY ELSEWHERE.
HOWEVER THE NAM AND RAP SHOW A VERY STRONG BARRIER JET DEVELOPING
THIS EVENING STRETCHING NORTH-SOUTH ALONG AND WEST OF HIGHWAY 83
WHICH COULD EASILY SUPPORT A WINTER STORM IF THE FRONTOGENESIS
WAS APPROPRIATELY JUXTAPOSED. THIS IS NOT THE CASE AS THE NAM
SHOWS THE FGEN AND HEAVY QPF MOSTLY EAST OF THE FCST AREA. THE
RAP MEANWHILE NOSES THE PV1.5 ANOMALY INTO SRN NEB AT 02Z AND
DEVELOPS SOME HEAVY SNOW ACROSS SWRN NEB. THIS IS A CONCERN WHICH
WILL BE CLOSELY MONITORED.
THE STRONG BARRIER JET WILL EASILY SUPPORT 30 MPH WINDS WITH
GUSTS TO 45 MPH. IN FACT THE NAM AND RAP SHOW GUSTS TO 60 MPH AT
00Z-03Z...THE HEIGHT OF THE STORM ACROSS SWRN AND NCNTL NEB.
SO EVERYONE OUTSIDE OF THE WINTER STORM WARNING HAS BEEN PLACED
IN A WINTER WEATHER ADVISORY FOR 3 TO 5 INCHES OF SNOW AND 30 TO
45 MPH WINDS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT MAR 9 2013
MAJOR SPRING/WINTER STORM WILL BE EXITING SUNDAY MORNING WITH
SOME LINGERING LIGHT SNOW ACROSS THE FAR EASTERN COUNTIES. WINDS
WILL CONTINUE TO BE GUSTY...AND WILL HIGHLIGHT PATCHY BLOWING
SNOW WHERE FALLING SNOW IS EXPECTED. PENDING TOTAL SNOW AND HOW
FLUFFY IT IS...MAY NEED TO CONTINUE BLOWING SNOW FURTHER WEST
EARLY SUNDAY. STILL QUESTIONING HOW FAR WEST THE HEAVY BAND OF
SNOW OVER CENTRAL NEB WILL BE.
SUNDAY HIGHS...WITH COLD HIGH PRESSURE BUILDING SOUTH ACROSS THE
NORTHERN PLAINS AND MUCH IF NOT ALL OF THE AREA EXPECTED TO SEE A
SNOW COVER...SHOULD HOLD CLOSE TO 30 DEGREES. ALTHOUGH THE SUN
WILL SPREADING FROM WEST TO EAST...WHICH SHOULD HELP TO START TO
MELT ROADWAYS.
SUNDAY NIGHT WITH AN ELONGATED HIGH ACROSS THE WESTERN
PLAINS...LIGHT WINDS AND MOSTLY CLEAR SKIES ALONG WITH SNOW
PACK...TEMPS SHOULD TANK. WIDESPREAD TEENS...WHICH MAY BE
CONSERVATIVE.
MONDAY INTO MID WEEK RIDGE BUILDS ACROSS THE WEST...WITH A TROUGH
TO PUSH ALONG THE NORTHERN STREAM...ACROSS SOUTHERN CANADA AND
THE GREAT LAKES. WEAK DISTURBANCE TO MOVE ALONG THE NW FLOW
ACROSS THE AREA...HOWEVER MOISTURE LIMITED AND DOUBT ANYTHING
WILL REACH THE GROUND AS TIMING IS A LITTLE SLOWER WITH PASSAGE
MORE OF A DAYTIME AND THE HEAT OF THE DAY SHOULD BE ENOUGH TO
KEEP ANYTHING FROM HITTING THE GROUND. ALSO EARLY IN THE WEEK AS
THE SNOW MELTS WILL NEED TO MONITOR FOR OVERNIGHT/MORNING FOG.
RIDGE EXPANDS AS THE WEEK CONTINUES...WITH STRONG WAA ALOFT WITH
THE WESTERN PART OF THE CWA SEEING DOUBLE DIGIT 850 TEMPS.
QUESTION WILL BE HOW LONG CAN THE SNOW REMAIN AND DAMPEN TEMPS.
GUIDANCE PUSHES HIGHS INTO THE 50S AND 60S FOR WEDNESDAY AND
THURSDAY. AS IS TYPICAL WITH MANY MARCH SNOW STORMS...EXPECT THIS
SNOW NOT TO STAY LONG. ALTHOUGH WEST WINDS ON THE LIGHT
SIDE...LESS THAN 15 MPH...SHOULD BE ENOUGH TO HELP MIX WITH THE
DOWNSLOPE COMPONENT AND HAVE FOLLOWED CLOSER TO GUIDANCE FOR THE
LATER HALF OF THE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1153 AM CST SAT MAR 9 2013
EXPECTING WIDESPREAD IFR/LIFR CONDITIONS TO CONTINUE THROUGH 03Z
TONIGHT...WITH SNOW...BLOWING SNOW...FREEZING
RAIN...THUNDERSTORMS...AND RAIN ALL POSSIBLE FOR AREA TERMINALS.
KVTN...KTIF...KANW AND KOGA HAVE SWITCHED OVER TO SNOW...WITH
PERIODIC VISIBILITY REDUCTIONS TO 1/2SM. AT KLBF...KIML...KONL &
KBBW...ONLY LIGHT RAIN HAS THUS FAR BEEN OBSERVED...HOWEVER CONDITIONS
ARE EXPECTED TO DETERIORATE THIS AFTERNOON AS COLD AIR UNDERCUTS THE
FALLING PRECIPITATION. A BRIEF PERIOD OF FREEZING RAIN MAY BE
POSSIBLE WHERE THE CHANGE OVER TO SNOW HAS NOT OCCURRED...INCLUDING
THE KLBF TERMINAL. IN ADDITION...STRONG NORTHERLY WIND GUSTS IN
EXCESS OF 30KTS WILL CONTINUE THROUGH THE TAF FORECAST
PERIOD...WHICH WOULD LOWER VISIBILITY FURTHER IF SNOW IS FALLING.
LATE THIS EVENING...IMPROVEMENT TO MVFR/VFR SHOULD COMMENCE FROM
NORTHWEST TO SOUTHEAST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR
NEZ006>010-025>029-036>038-057>059-069>071.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR NEZ004-
005-022>024-035-056-094.
&&
$$
UPDATE...JACOBS
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1154 AM CST SAT MAR 9 2013
.UPDATE...
ISSUED AT 1021 CST SAT MAR 9 2013
OVERALL IDEA OF THE FORECAST REMAINS ON TRACK WITH ONLY MINOR
REVISIONS TO FRESHEN UP WIND SPEEDS...TIMING OF THE SNOW
CHANGEOVER...AND FREEZING RAIN AMOUNTS. PHONE CALLS IN AND AROUND
KVTN THIS MORNING SUGGESTED ABOUT A TENTH OF AN INCH OF ICE OR
LESS ACCUMULATION...THUS WILL TREND DOWN THE QUARTER OF AN INCH WE
HAD GOING FOR THE CENTRAL SAND HILLS...WITH WORDING OF MINOR
ICE ACCUMULATIONS. OTHERWISE ONCE THE CHANGE OVER TO SNOW
OCCURS...SNOW RATES OF AN INCH PER HOUR HAVE BEEN NOTED UNDER THE
HEAVIEST OF BANDS. 12Z NAM APPEARS REASONABLE AT THIS
JUNCTURE...THUS TRENDED IN THAT DIRECTION. THE NARROW BAND OF QPF
WILL CONTINUE THROUGH MID AFTERNOON ACROSS NORTHWEST NEBRASKA
ALONG A STRONG BAND OF H7 FRONTOGENESIS AND WITH AID FROM THE LFQ
OF A 90KT JET. SNOW ACCUMULATIONS OF 6 INCHES OR GREATER STILL
APPEARS LIKELY ACROSS NORTHWEST NEBRASKA. BUT LATER TODAY...SNOW
WILL BEGIN TO TAPER OFF BY LATE AFTERNOON AS THE NORTHERN STREAM
RACES SOUTHEAST ACROSS THE NORTHERN PLAINS AND ALLOWS FOR THE
INTRUSION OF DRIER AIR INTO THE NORTHERN REACHES OF THE CWA.
HOWEVER ALL NEAR TERM SOLUTIONS DO INDICATE THE FORMATION OF A
SECOND AREA OF DEFORMATION ACROSS FAR SOUTHEASTERN PORTIONS OF THE
FORECAST AREA...ALIGNED NORTHEAST TO SOUTHWEST WITH THE EASTWARD
ADVANCING MID LEVEL FRONTOGENETIC FORCING...FORECAST FOR THIS
SECOND BAND APPEARS ON TRACK AT THIS TIME...WILL REVISIT EXPECTED
SNOW AMOUNTS AS ADDITIONAL GUIDANCE COMES IN THIS MORNING.
UPDATE ISSUED AT 700 AM CST SAT MAR 9 2013
NO NEW DATA WAS AVAILABLE FOR THE QPF FORECAST BUT INDICATIONS ARE
THE RAP13 IS VERIFYING ACROSS NRN NEB WITH OVER 1/2 INCH OF ICE AT
THE KVTN ASOS. AFTER SLOWING THE EASTERN PROGRESSION OF THE RAIN
CHANGE LINE USING THE RUC...NORTH WINDS HAVE INCREASED AND NOW THE
RAIN CHANGE LINE IS ROUGHLY FROM CHAPPELL TO THEDFORD TO AINSWORTH.
SO THE NAM MAY BE VERIFYING BETTER AND IT WAS USED IN THE NEW
FORECAST.
A NEW WIND FORECAST USING NAM...GEM...MET AND MAV GUIDANCE
PRODUCED GUSTS TO 50 MPH THIS AFTERNOON AND THIS EVENING WHICH IS
CONSISTENT WITH THE 60KT BARRIER JET FCST BY BOTH MODELS. THIS
STRUCTURE IS FCST TO SET UP ACROSS THE ERN PANHANDLE THIS MORNING
AND MOVE SLOWLY EAST THIS AFTN AND TONIGHT ACTING AS A FOCUS FOR
SNOW AND STRONG WINDS.
THERE IS NO CHANGE TO THE DYNAMICS. STRONG FRONTOGENESIS HANGS
UP ACROSS THE NORTHWEST TODAY AND DECAYS WHILE A NEW STRUCTURE
DEVELOPS FARTHER EAST THIS EVENING. THE RAP HAS COME IN LINE WITH
THE NAM AND ECM DEVELOPING THE NEW SNOW EAST OF THE FCST AREA
WHILE THE 06Z GFS HANGS IT UP ACROSS NCNTL AND SWRN NEB...VERY
TROUBLING. GIVEN THE VERY STRONG WINDS DEVELOPING...EVEN AN 1/2
INCH PER HOUR SNOWFALL RATE COULD PRODUCE BLIZZARD CONDITIONS.
THE SNOW SHOULD GRADUALLY END OVERNIGHT AND SUNDAY MORNING WEST TO
EAST WITH CLEARING SKIES TO FOLLOW. WINDY CONDITIONS CONTINUE
SUNDAY MORNING IN THE EAST.
UPDATE ISSUED AT 527 AM CST SAT MAR 9 2013
THE RAP13 MODEL SHOWS A SLOWER TRANSITION TO SNOW THAN THE NAM. IN
FACT THE RAP CARRIES A BROAD AREA OF FREEZING RAIN AHEAD OF THE
CHANGEOVER TO SNOW. THIS IS WELL SUPPORTED IN THE MODEL TEMPERATURE
FIELDS. SO A NEW FORECAST IS OUT WHICH HEIGHTENS THE THREAT OF
FREEZING RAIN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT MAR 9 2013
TWO ROUNDS OF THOUGHT WITH THE STORM. ONE IS FOR A STRONG FGEN
FORCED BAND OF SNOW DEVELOPING ACROSS NORTHWEST NEBRASKA TODAY
WHICH MOST SOLNS AGREE ON TO VARYING DEGREES. THE SECOND IS FOR
ANOTHER STRONG BAND OF SNOW TO DEVELOP ACROSS SOUTH CENTRAL
NEBRASKA TONIGHT AS THE FIRST BAND DECAYS. THE GEM REGIONAL AND
GFS ARE VERY FAR NORTHWEST WITH THIS BAND SIGNALING A WINTER
STORM FOR NCNTL NEB WHILE THE NAM AND ECM ARE SAFELY EAST OF THE
FCST AREA. A BLEND OF NAM...GEM AND ECM WERE USED FOR THE LATEST
FCST WHICH PROVIDES A WINTER STORM ACROSS THE NORTHWEST AND A
WINTER WEATHER ADVISORY ELSEWHERE.
HOWEVER THE NAM AND RAP SHOW A VERY STRONG BARRIER JET DEVELOPING
THIS EVENING STRETCHING NORTH-SOUTH ALONG AND WEST OF HIGHWAY 83
WHICH COULD EASILY SUPPORT A WINTER STORM IF THE FRONTOGENESIS
WAS APPROPRIATELY JUXTAPOSED. THIS IS NOT THE CASE AS THE NAM
SHOWS THE FGEN AND HEAVY QPF MOSTLY EAST OF THE FCST AREA. THE
RAP MEANWHILE NOSES THE PV1.5 ANOMALY INTO SRN NEB AT 02Z AND
DEVELOPS SOME HEAVY SNOW ACROSS SWRN NEB. THIS IS A CONCERN WHICH
WILL BE CLOSELY MONITORED.
THE STRONG BARRIER JET WILL EASILY SUPPORT 30 MPH WINDS WITH
GUSTS TO 45 MPH. IN FACT THE NAM AND RAP SHOW GUSTS TO 60 MPH AT
00Z-03Z...THE HEIGHT OF THE STORM ACROSS SWRN AND NCNTL NEB.
SO EVERYONE OUTSIDE OF THE WINTER STORM WARNING HAS BEEN PLACED
IN A WINTER WEATHER ADVISORY FOR 3 TO 5 INCHES OF SNOW AND 30 TO
45 MPH WINDS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT MAR 9 2013
MAJOR SPRING/WINTER STORM WILL BE EXITING SUNDAY MORNING WITH
SOME LINGERING LIGHT SNOW ACROSS THE FAR EASTERN COUNTIES. WINDS
WILL CONTINUE TO BE GUSTY...AND WILL HIGHLIGHT PATCHY BLOWING
SNOW WHERE FALLING SNOW IS EXPECTED. PENDING TOTAL SNOW AND HOW
FLUFFY IT IS...MAY NEED TO CONTINUE BLOWING SNOW FURTHER WEST
EARLY SUNDAY. STILL QUESTIONING HOW FAR WEST THE HEAVY BAND OF
SNOW OVER CENTRAL NEB WILL BE.
SUNDAY HIGHS...WITH COLD HIGH PRESSURE BUILDING SOUTH ACROSS THE
NORTHERN PLAINS AND MUCH IF NOT ALL OF THE AREA EXPECTED TO SEE A
SNOW COVER...SHOULD HOLD CLOSE TO 30 DEGREES. ALTHOUGH THE SUN
WILL SPREADING FROM WEST TO EAST...WHICH SHOULD HELP TO START TO
MELT ROADWAYS.
SUNDAY NIGHT WITH AN ELONGATED HIGH ACROSS THE WESTERN
PLAINS...LIGHT WINDS AND MOSTLY CLEAR SKIES ALONG WITH SNOW
PACK...TEMPS SHOULD TANK. WIDESPREAD TEENS...WHICH MAY BE
CONSERVATIVE.
MONDAY INTO MID WEEK RIDGE BUILDS ACROSS THE WEST...WITH A TROUGH
TO PUSH ALONG THE NORTHERN STREAM...ACROSS SOUTHERN CANADA AND
THE GREAT LAKES. WEAK DISTURBANCE TO MOVE ALONG THE NW FLOW
ACROSS THE AREA...HOWEVER MOISTURE LIMITED AND DOUBT ANYTHING
WILL REACH THE GROUND AS TIMING IS A LITTLE SLOWER WITH PASSAGE
MORE OF A DAYTIME AND THE HEAT OF THE DAY SHOULD BE ENOUGH TO
KEEP ANYTHING FROM HITTING THE GROUND. ALSO EARLY IN THE WEEK AS
THE SNOW MELTS WILL NEED TO MONITOR FOR OVERNIGHT/MORNING FOG.
RIDGE EXPANDS AS THE WEEK CONTINUES...WITH STRONG WAA ALOFT WITH
THE WESTERN PART OF THE CWA SEEING DOUBLE DIGIT 850 TEMPS.
QUESTION WILL BE HOW LONG CAN THE SNOW REMAIN AND DAMPEN TEMPS.
GUIDANCE PUSHES HIGHS INTO THE 50S AND 60S FOR WEDNESDAY AND
THURSDAY. AS IS TYPICAL WITH MANY MARCH SNOW STORMS...EXPECT THIS
SNOW NOT TO STAY LONG. ALTHOUGH WEST WINDS ON THE LIGHT
SIDE...LESS THAN 15 MPH...SHOULD BE ENOUGH TO HELP MIX WITH THE
DOWNSLOPE COMPONENT AND HAVE FOLLOWED CLOSER TO GUIDANCE FOR THE
LATER HALF OF THE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1153 AM CST SAT MAR 9 2013
EXPECTING WIDESPREAD IFR/LIFR CONDITIONS TO CONTINUE THROUGH 03Z
TONIGHT...WITH SNOW...BLOWING SNOW...FREEZING
RAIN...THUNDERSTORMS...AND RAIN ALL POSSIBLE FOR AREA TERMINALS.
KVTN...KTIF...KANW AND KOGA HAVE SWITCHED OVER TO SNOW...WITH
PERIODIC VISIBILITY REDUCTIONS TO 1/2SM. AT KLBF...KIML...KONL &
KBBW...ONLY LIGHT RAIN HAS THUS FAR BEEN OBSERVED...HOWEVER CONDITIONS
ARE EXPECTED TO DETERIORATE THIS AFTERNOON AS COLD AIR UNDERCUTS THE
FALLING PRECIPITATION. A BRIEF PERIOD OF FREEZING RAIN MAY BE
POSSIBLE WHERE THE CHANGE OVER TO SNOW HAS NOT OCCURRED...INCLUDING
THE KLBF TERMINAL. IN ADDITION...STRONG NORTHERLY WIND GUSTS IN
EXCESS OF 30KTS WILL CONTINUE THROUGH THE TAF FORECAST
PERIOD...WHICH WOULD LOWER VISIBILITY FURTHER IF SNOW IS FALLING.
LATE THIS EVENING...IMPROVEMENT TO MVFR/VFR SHOULD COMMENCE FROM
NORTHWEST TO SOUTHEAST.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR
NEZ006-008-025-026-036-057-058-069.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT SUNDAY FOR NEZ007-009-010-
027>029-037-038-059-070-071.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR NEZ004-
005-022>024-035-056-094.
&&
$$
UPDATE...JACOBS
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...JACOBS
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1021 AM CST SAT MAR 9 2013
.UPDATE...
ISSUED AT 1021 CST SAT MAR 9 2013
OVERALL IDEA OF THE FORECAST REMAINS ON TRACK WITH ONLY MINOR
REVISIONS TO FRESHEN UP WIND SPEEDS...TIMING OF THE SNOW
CHANGEOVER...AND FREEZING RAIN AMOUNTS. PHONE CALLS IN AND AROUND
KVTN THIS MORNING SUGGESTED ABOUT A TENTH OF AN INCH OF ICE OR
LESS ACCUMULATION...THUS WILL TREND DOWN THE QUARTER OF AN INCH WE
HAD GOING FOR THE CENTRAL SAND HILLS...WITH WORDING OF MINOR
ICE ACCUMULATIONS. OTHERWISE ONCE THE CHANGE OVER TO SNOW
OCCURS...SNOW RATES OF AN INCH PER HOUR HAVE BEEN NOTED UNDER THE
HEAVIEST OF BANDS. 12Z NAM APPEARS REASONABLE AT THIS
JUNCTURE...THUS TRENDED IN THAT DIRECTION. THE NARROW BAND OF QPF
WILL CONTINUE THROUGH MID AFTERNOON ACROSS NORTHWEST NEBRASKA
ALONG A STRONG BAND OF H7 FRONTOGENESIS AND WITH AID FROM THE LFQ
OF A 90KT JET. SNOW ACCUMULATIONS OF 6 INCHES OR GREATER STILL
APPEARS LIKELY ACROSS NORTHWEST NEBRASKA. BUT LATER TODAY...SNOW
WILL BEGIN TO TAPER OFF BY LATE AFTERNOON AS THE NORTHERN STREAM
RACES SOUTHEAST ACROSS THE NORTHERN PLAINS AND ALLOWS FOR THE
INTRUSION OF DRIER AIR INTO THE NORTHERN REACHES OF THE CWA.
HOWEVER ALL NEAR TERM SOLUTIONS DO INDICATE THE FORMATION OF A
SECOND AREA OF DEFORMATION ACROSS FAR SOUTHEASTERN PORTIONS OF THE
FORECAST AREA...ALIGNED NORTHEAST TO SOUTHWEST WITH THE EASTWARD
ADVANCING MID LEVEL FRONTOGENETIC FORCING...FORECAST FOR THIS
SECOND BAND APPEARS ON TRACK AT THIS TIME...WILL REVISIT EXPECTED
SNOW AMOUNTS AS ADDITIONAL GUIDANCE COMES IN THIS MORNING.
UPDATE ISSUED AT 700 AM CST SAT MAR 9 2013
NO NEW DATA WAS AVAILABLE FOR THE QPF FORECAST BUT INDICATIONS ARE
THE RAP13 IS VERIFYING ACROSS NRN NEB WITH OVER 1/2 INCH OF ICE AT
THE KVTN ASOS. AFTER SLOWING THE EASTERN PROGRESSION OF THE RAIN
CHANGE LINE USING THE RUC...NORTH WINDS HAVE INCREASED AND NOW THE
RAIN CHANGE LINE IS ROUGHLY FROM CHAPPELL TO THEDFORD TO AINSWORTH.
SO THE NAM MAY BE VERIFYING BETTER AND IT WAS USED IN THE NEW
FORECAST.
A NEW WIND FORECAST USING NAM...GEM...MET AND MAV GUIDANCE
PRODUCED GUSTS TO 50 MPH THIS AFTERNOON AND THIS EVENING WHICH IS
CONSISTENT WITH THE 60KT BARRIER JET FCST BY BOTH MODELS. THIS
STRUCTURE IS FCST TO SET UP ACROSS THE ERN PANHANDLE THIS MORNING
AND MOVE SLOWLY EAST THIS AFTN AND TONIGHT ACTING AS A FOCUS FOR
SNOW AND STRONG WINDS.
THERE IS NO CHANGE TO THE DYNAMICS. STRONG FRONTOGENESIS HANGS
UP ACROSS THE NORTHWEST TODAY AND DECAYS WHILE A NEW STRUCTURE
DEVELOPS FARTHER EAST THIS EVENING. THE RAP HAS COME IN LINE WITH
THE NAM AND ECM DEVELOPING THE NEW SNOW EAST OF THE FCST AREA
WHILE THE 06Z GFS HANGS IT UP ACROSS NCNTL AND SWRN NEB...VERY
TROUBLING. GIVEN THE VERY STRONG WINDS DEVELOPING...EVEN AN 1/2
INCH PER HOUR SNOWFALL RATE COULD PRODUCE BLIZZARD CONDITIONS.
THE SNOW SHOULD GRADUALLY END OVERNIGHT AND SUNDAY MORNING WEST TO
EAST WITH CLEARING SKIES TO FOLLOW. WINDY CONDITIONS CONTINUE
SUNDAY MORNING IN THE EAST.
UPDATE ISSUED AT 527 AM CST SAT MAR 9 2013
THE RAP13 MODEL SHOWS A SLOWER TRANSITION TO SNOW THAN THE NAM. IN
FACT THE RAP CARRIES A BROAD AREA OF FREEZING RAIN AHEAD OF THE
CHANGEOVER TO SNOW. THIS IS WELL SUPPORTED IN THE MODEL TEMPERATURE
FIELDS. SO A NEW FORECAST IS OUT WHICH HEIGHTENS THE THREAT OF
FREEZING RAIN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT MAR 9 2013
TWO ROUNDS OF THOUGHT WITH THE STORM. ONE IS FOR A STRONG FGEN
FORCED BAND OF SNOW DEVELOPING ACROSS NORTHWEST NEBRASKA TODAY
WHICH MOST SOLNS AGREE ON TO VARYING DEGREES. THE SECOND IS FOR
ANOTHER STRONG BAND OF SNOW TO DEVELOP ACROSS SOUTH CENTRAL
NEBRASKA TONIGHT AS THE FIRST BAND DECAYS. THE GEM REGIONAL AND
GFS ARE VERY FAR NORTHWEST WITH THIS BAND SIGNALING A WINTER
STORM FOR NCNTL NEB WHILE THE NAM AND ECM ARE SAFELY EAST OF THE
FCST AREA. A BLEND OF NAM...GEM AND ECM WERE USED FOR THE LATEST
FCST WHICH PROVIDES A WINTER STORM ACROSS THE NORTHWEST AND A
WINTER WEATHER ADVISORY ELSEWHERE.
HOWEVER THE NAM AND RAP SHOW A VERY STRONG BARRIER JET DEVELOPING
THIS EVENING STRETCHING NORTH-SOUTH ALONG AND WEST OF HIGHWAY 83
WHICH COULD EASILY SUPPORT A WINTER STORM IF THE FRONTOGENESIS
WAS APPROPRIATELY JUXTAPOSED. THIS IS NOT THE CASE AS THE NAM
SHOWS THE FGEN AND HEAVY QPF MOSTLY EAST OF THE FCST AREA. THE
RAP MEANWHILE NOSES THE PV1.5 ANOMALY INTO SRN NEB AT 02Z AND
DEVELOPS SOME HEAVY SNOW ACROSS SWRN NEB. THIS IS A CONCERN WHICH
WILL BE CLOSELY MONITORED.
THE STRONG BARRIER JET WILL EASILY SUPPORT 30 MPH WINDS WITH
GUSTS TO 45 MPH. IN FACT THE NAM AND RAP SHOW GUSTS TO 60 MPH AT
00Z-03Z...THE HEIGHT OF THE STORM ACROSS SWRN AND NCNTL NEB.
SO EVERYONE OUTSIDE OF THE WINTER STORM WARNING HAS BEEN PLACED
IN A WINTER WEATHER ADVISORY FOR 3 TO 5 INCHES OF SNOW AND 30 TO
45 MPH WINDS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT MAR 9 2013
MAJOR SPRING/WINTER STORM WILL BE EXITING SUNDAY MORNING WITH
SOME LINGERING LIGHT SNOW ACROSS THE FAR EASTERN COUNTIES. WINDS
WILL CONTINUE TO BE GUSTY...AND WILL HIGHLIGHT PATCHY BLOWING
SNOW WHERE FALLING SNOW IS EXPECTED. PENDING TOTAL SNOW AND HOW
FLUFFY IT IS...MAY NEED TO CONTINUE BLOWING SNOW FURTHER WEST
EARLY SUNDAY. STILL QUESTIONING HOW FAR WEST THE HEAVY BAND OF
SNOW OVER CENTRAL NEB WILL BE.
SUNDAY HIGHS...WITH COLD HIGH PRESSURE BUILDING SOUTH ACROSS THE
NORTHERN PLAINS AND MUCH IF NOT ALL OF THE AREA EXPECTED TO SEE A
SNOW COVER...SHOULD HOLD CLOSE TO 30 DEGREES. ALTHOUGH THE SUN
WILL SPREADING FROM WEST TO EAST...WHICH SHOULD HELP TO START TO
MELT ROADWAYS.
SUNDAY NIGHT WITH AN ELONGATED HIGH ACROSS THE WESTERN
PLAINS...LIGHT WINDS AND MOSTLY CLEAR SKIES ALONG WITH SNOW
PACK...TEMPS SHOULD TANK. WIDESPREAD TEENS...WHICH MAY BE
CONSERVATIVE.
MONDAY INTO MID WEEK RIDGE BUILDS ACROSS THE WEST...WITH A TROUGH
TO PUSH ALONG THE NORTHERN STREAM...ACROSS SOUTHERN CANADA AND
THE GREAT LAKES. WEAK DISTURBANCE TO MOVE ALONG THE NW FLOW
ACROSS THE AREA...HOWEVER MOISTURE LIMITED AND DOUBT ANYTHING
WILL REACH THE GROUND AS TIMING IS A LITTLE SLOWER WITH PASSAGE
MORE OF A DAYTIME AND THE HEAT OF THE DAY SHOULD BE ENOUGH TO
KEEP ANYTHING FROM HITTING THE GROUND. ALSO EARLY IN THE WEEK AS
THE SNOW MELTS WILL NEED TO MONITOR FOR OVERNIGHT/MORNING FOG.
RIDGE EXPANDS AS THE WEEK CONTINUES...WITH STRONG WAA ALOFT WITH
THE WESTERN PART OF THE CWA SEEING DOUBLE DIGIT 850 TEMPS.
QUESTION WILL BE HOW LONG CAN THE SNOW REMAIN AND DAMPEN TEMPS.
GUIDANCE PUSHES HIGHS INTO THE 50S AND 60S FOR WEDNESDAY AND
THURSDAY. AS IS TYPICAL WITH MANY MARCH SNOW STORMS...EXPECT THIS
SNOW NOT TO STAY LONG. ALTHOUGH WEST WINDS ON THE LIGHT
SIDE...LESS THAN 15 MPH...SHOULD BE ENOUGH TO HELP MIX WITH THE
DOWNSLOPE COMPONENT AND HAVE FOLLOWED CLOSER TO GUIDANCE FOR THE
LATER HALF OF THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 537 AM CST SAT MAR 9 2013
EXPECTING IFR/LIFR TO CONTINUE THROUGH 03Z THIS EVENING IN
SNOW...BLOWING SNOW...FOG...RAIN AND FREEZING RAIN. THEREAFTER AN
IMPROVEMENT TO MVFR/VFR SHOULD COMMENCE FROM NORTHWEST TO
SOUTHEAST. WINDS TODAY WILL INCREASE TO 36030G40KT AND DIMINISH
LATE THIS EVENING TO 34020G30KT BY 12Z SUNDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR
NEZ006-008-025-026-036-057-058-069.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT SUNDAY FOR NEZ007-009-010-
027>029-037-038-059-070-071.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR NEZ004-
005-022>024-035-056-094.
&&
$$
UPDATE...JACOBS
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
719 AM CST SAT MAR 9 2013
.UPDATE...
ISSUED AT 700 AM CST SAT MAR 9 2013
NO NEW DATA WAS AVAILABLE FOR THE QPF FORECAST BUT INDICATIONS ARE
THE RAP13 IS VERIFYING ACROSS NRN NEB WITH OVER 1/2 INCH OF ICE AT
THE KVTN ASOS. AFTER SLOWING THE EASTERN PROGRESSION OF THE RAIN
CHANGE LINE USING THE RUC...NORTH WINDS HAVE INCREASED AND NOW THE
RAIN CHANGE LINE IS ROUGHLY FROM CHAPPELL TO THEDFORD TO AINSWORTH.
SO THE NAM MAY BE VERIFYING BETTER AND IT WAS USED IN THE NEW
FORECAST.
A NEW WIND FORECAST USING NAM...GEM...MET AND MAV GUIDANCE
PRODUCED GUSTS TO 50 MPH THIS AFTERNOON AND THIS EVENING WHICH IS
CONSISTENT WITH THE 60KT BARRIER JET FCST BY BOTH MODELS. THIS
STRUCTURE IS FCST TO SET UP ACROSS THE ERN PANHANDLE THIS MORNING
AND MOVE SLOWLY EAST THIS AFTN AND TONIGHT ACTING AS A FOCUS FOR
SNOW AND STRONG WINDS.
THERE IS NO CHANGE TO THE DYNAMICS. STRONG FRONTOGENESIS HANGS
UP ACROSS THE NORTHWEST TODAY AND DECAYS WHILE A NEW STRUCTURE
DEVELOPS FARTHER EAST THIS EVENING. THE RAP HAS COME IN LINE WITH
THE NAM AND ECM DEVELOPING THE NEW SNOW EAST OF THE FCST AREA
WHILE THE 06Z GFS HANGS IT UP ACROSS NCNTL AND SWRN NEB...VERY
TROUBLING. GIVEN THE VERY STRONG WINDS DEVELOPING...EVEN AN 1/2
INCH PER HOUR SNOWFALL RATE COULD PRODUCE BLIZZARD CONDITIONS.
THE SNOW SHOULD GRADUALLY END OVERNIGHT AND SUNDAY MORNING WEST TO
EAST WITH CLEARING SKIES TO FOLLOW. WINDY CONDITIONS CONTINUE
SUNDAY MORNING IN THE EAST.
UPDATE ISSUED AT 527 AM CST SAT MAR 9 2013
THE RAP13 MODEL SHOWS A SLOWER TRANSITION TO SNOW THAN THE NAM. IN
FACT THE RAP CARRIES A BROAD AREA OF FREEZING RAIN AHEAD OF THE
CHANGEOVER TO SNOW. THIS IS WELL SUPPORTED IN THE MODEL TEMPERATURE
FIELDS. SO A NEW FORECAST IS OUT WHICH HEIGHTENS THE THREAT OF
FREEZING RAIN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT MAR 9 2013
TWO ROUNDS OF THOUGHT WITH THE STORM. ONE IS FOR A STRONG FGEN
FORCED BAND OF SNOW DEVELOPING ACROSS NORTHWEST NEBRASKA TODAY
WHICH MOST SOLNS AGREE ON TO VARYING DEGREES. THE SECOND IS FOR
ANOTHER STRONG BAND OF SNOW TO DEVELOP ACROSS SOUTH CENTRAL
NEBRASKA TONIGHT AS THE FIRST BAND DECAYS. THE GEM REGIONAL AND
GFS ARE VERY FAR NORTHWEST WITH THIS BAND SIGNALING A WINTER
STORM FOR NCNTL NEB WHILE THE NAM AND ECM ARE SAFELY EAST OF THE
FCST AREA. A BLEND OF NAM...GEM AND ECM WERE USED FOR THE LATEST
FCST WHICH PROVIDES A WINTER STORM ACROSS THE NORTHWEST AND A
WINTER WEATHER ADVISORY ELSEWHERE.
HOWEVER THE NAM AND RAP SHOW A VERY STRONG BARRIER JET DEVELOPING
THIS EVENING STRETCHING NORTH-SOUTH ALONG AND WEST OF HIGHWAY 83
WHICH COULD EASILY SUPPORT A WINTER STORM IF THE FRONTOGENESIS
WAS APPROPRIATELY JUXTAPOSED. THIS IS NOT THE CASE AS THE NAM
SHOWS THE FGEN AND HEAVY QPF MOSTLY EAST OF THE FCST AREA. THE
RAP MEANWHILE NOSES THE PV1.5 ANOMALY INTO SRN NEB AT 02Z AND
DEVELOPS SOME HEAVY SNOW ACROSS SWRN NEB. THIS IS A CONCERN WHICH
WILL BE CLOSELY MONITORED.
THE STRONG BARRIER JET WILL EASILY SUPPORT 30 MPH WINDS WITH
GUSTS TO 45 MPH. IN FACT THE NAM AND RAP SHOW GUSTS TO 60 MPH AT
00Z-03Z...THE HEIGHT OF THE STORM ACROSS SWRN AND NCNTL NEB.
SO EVERYONE OUTSIDE OF THE WINTER STORM WARNING HAS BEEN PLACED
IN A WINTER WEATHER ADVISORY FOR 3 TO 5 INCHES OF SNOW AND 30 TO
45 MPH WINDS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT MAR 9 2013
MAJOR SPRING/WINTER STORM WILL BE EXITING SUNDAY MORNING WITH
SOME LINGERING LIGHT SNOW ACROSS THE FAR EASTERN COUNTIES. WINDS
WILL CONTINUE TO BE GUSTY...AND WILL HIGHLIGHT PATCHY BLOWING
SNOW WHERE FALLING SNOW IS EXPECTED. PENDING TOTAL SNOW AND HOW
FLUFFY IT IS...MAY NEED TO CONTINUE BLOWING SNOW FURTHER WEST
EARLY SUNDAY. STILL QUESTIONING HOW FAR WEST THE HEAVY BAND OF
SNOW OVER CENTRAL NEB WILL BE.
SUNDAY HIGHS...WITH COLD HIGH PRESSURE BUILDING SOUTH ACROSS THE
NORTHERN PLAINS AND MUCH IF NOT ALL OF THE AREA EXPECTED TO SEE A
SNOW COVER...SHOULD HOLD CLOSE TO 30 DEGREES. ALTHOUGH THE SUN
WILL SPREADING FROM WEST TO EAST...WHICH SHOULD HELP TO START TO
MELT ROADWAYS.
SUNDAY NIGHT WITH AN ELONGATED HIGH ACROSS THE WESTERN
PLAINS...LIGHT WINDS AND MOSTLY CLEAR SKIES ALONG WITH SNOW
PACK...TEMPS SHOULD TANK. WIDESPREAD TEENS...WHICH MAY BE
CONSERVATIVE.
MONDAY INTO MID WEEK RIDGE BUILDS ACROSS THE WEST...WITH A TROUGH
TO PUSH ALONG THE NORTHERN STREAM...ACROSS SOUTHERN CANADA AND
THE GREAT LAKES. WEAK DISTURBANCE TO MOVE ALONG THE NW FLOW
ACROSS THE AREA...HOWEVER MOISTURE LIMITED AND DOUBT ANYTHING
WILL REACH THE GROUND AS TIMING IS A LITTLE SLOWER WITH PASSAGE
MORE OF A DAYTIME AND THE HEAT OF THE DAY SHOULD BE ENOUGH TO
KEEP ANYTHING FROM HITTING THE GROUND. ALSO EARLY IN THE WEEK AS
THE SNOW MELTS WILL NEED TO MONITOR FOR OVERNIGHT/MORNING FOG.
RIDGE EXPANDS AS THE WEEK CONTINUES...WITH STRONG WAA ALOFT WITH
THE WESTERN PART OF THE CWA SEEING DOUBLE DIGIT 850 TEMPS.
QUESTION WILL BE HOW LONG CAN THE SNOW REMAIN AND DAMPEN TEMPS.
GUIDANCE PUSHES HIGHS INTO THE 50S AND 60S FOR WEDNESDAY AND
THURSDAY. AS IS TYPICAL WITH MANY MARCH SNOW STORMS...EXPECT THIS
SNOW NOT TO STAY LONG. ALTHOUGH WEST WINDS ON THE LIGHT
SIDE...LESS THAN 15 MPH...SHOULD BE ENOUGH TO HELP MIX WITH THE
DOWNSLOPE COMPONENT AND HAVE FOLLOWED CLOSER TO GUIDANCE FOR THE
LATER HALF OF THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 537 AM CST SAT MAR 9 2013
EXPECTING IFR/LIFR TO CONTINUE THROUGH 03Z THIS EVENING IN
SNOW...BLOWING SNOW...FOG...RAIN AND FREEZING RAIN. THEREAFTER AN
IMPROVEMENT TO MVFR/VFR SHOULD COMMENCE FROM NORTHWEST TO
SOUTHEAST. WINDS TODAY WILL INCREASE TO 36030G40KT AND DIMINISH
LATE THIS EVENING TO 34020G30KT BY 12Z SUNDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR
NEZ006-008-025-026-036-057-058-069.
WINTER WEATHER ADVISORY FROM NOON CST TODAY TO 7 AM CDT SUNDAY
FOR NEZ007-009-010-027>029-037-038-059-070-071.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR NEZ004-
005-022>024-035-056-094.
&&
$$
UPDATE...CDC
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
540 AM CST SAT MAR 9 2013
.UPDATE...
ISSUED AT 527 AM CST SAT MAR 9 2013
THE RAP13 MODEL SHOWS A SLOWER TRANSITION TO SNOW THAN THE NAM. IN
FACT THE RAP CARRIES A BROAD AREA OF FREEZING RAIN AHEAD OF THE
CHANGEOVER TO SNOW. THIS IS WELL SUPPORTED IN THE MODEL TEMPERATURE
FIELDS. SO A NEW FORECAST IS OUT WHICH HEIGHTENS THE THREAT OF
FREEZING RAIN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT MAR 9 2013
TWO ROUNDS OF THOUGHT WITH THE STORM. ONE IS FOR A STRONG FGEN
FORCED BAND OF SNOW DEVELOPING ACROSS NORTHWEST NEBRASKA TODAY
WHICH MOST SOLNS AGREE ON TO VARYING DEGREES. THE SECOND IS FOR
ANOTHER STRONG BAND OF SNOW TO DEVELOP ACROSS SOUTH CENTRAL
NEBRASKA TONIGHT AS THE FIRST BAND DECAYS. THE GEM REGIONAL AND
GFS ARE VERY FAR NORTHWEST WITH THIS BAND SIGNALING A WINTER
STORM FOR NCNTL NEB WHILE THE NAM AND ECM ARE SAFELY EAST OF THE
FCST AREA. A BLEND OF NAM...GEM AND ECM WERE USED FOR THE LATEST
FCST WHICH PROVIDES A WINTER STORM ACROSS THE NORTHWEST AND A
WINTER WEATHER ADVISORY ELSEWHERE.
HOWEVER THE NAM AND RAP SHOW A VERY STRONG BARRIER JET DEVELOPING
THIS EVENING STRETCHING NORTH-SOUTH ALONG AND WEST OF HIGHWAY 83
WHICH COULD EASILY SUPPORT A WINTER STORM IF THE FRONTOGENESIS
WAS APPROPRIATELY JUXTAPOSED. THIS IS NOT THE CASE AS THE NAM
SHOWS THE FGEN AND HEAVY QPF MOSTLY EAST OF THE FCST AREA. THE
RAP MEANWHILE NOSES THE PV1.5 ANOMALY INTO SRN NEB AT 02Z AND
DEVELOPS SOME HEAVY SNOW ACROSS SWRN NEB. THIS IS A CONCERN WHICH
WILL BE CLOSELY MONITORED.
THE STRONG BARRIER JET WILL EASILY SUPPORT 30 MPH WINDS WITH
GUSTS TO 45 MPH. IN FACT THE NAM AND RAP SHOW GUSTS TO 60 MPH AT
00Z-03Z...THE HEIGHT OF THE STORM ACROSS SWRN AND NCNTL NEB.
SO EVERYONE OUTSIDE OF THE WINTER STORM WARNING HAS BEEN PLACED
IN A WINTER WEATHER ADVISORY FOR 3 TO 5 INCHES OF SNOW AND 30 TO
45 MPH WINDS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT MAR 9 2013
MAJOR SPRING/WINTER STORM WILL BE EXITING SUNDAY MORNING WITH
SOME LINGERING LIGHT SNOW ACROSS THE FAR EASTERN COUNTIES. WINDS
WILL CONTINUE TO BE GUSTY...AND WILL HIGHLIGHT PATCHY BLOWING
SNOW WHERE FALLING SNOW IS EXPECTED. PENDING TOTAL SNOW AND HOW
FLUFFY IT IS...MAY NEED TO CONTINUE BLOWING SNOW FURTHER WEST
EARLY SUNDAY. STILL QUESTIONING HOW FAR WEST THE HEAVY BAND OF
SNOW OVER CENTRAL NEB WILL BE.
SUNDAY HIGHS...WITH COLD HIGH PRESSURE BUILDING SOUTH ACROSS THE
NORTHERN PLAINS AND MUCH IF NOT ALL OF THE AREA EXPECTED TO SEE A
SNOW COVER...SHOULD HOLD CLOSE TO 30 DEGREES. ALTHOUGH THE SUN
WILL SPREADING FROM WEST TO EAST...WHICH SHOULD HELP TO START TO
MELT ROADWAYS.
SUNDAY NIGHT WITH AN ELONGATED HIGH ACROSS THE WESTERN
PLAINS...LIGHT WINDS AND MOSTLY CLEAR SKIES ALONG WITH SNOW
PACK...TEMPS SHOULD TANK. WIDESPREAD TEENS...WHICH MAY BE
CONSERVATIVE.
MONDAY INTO MID WEEK RIDGE BUILDS ACROSS THE WEST...WITH A TROUGH
TO PUSH ALONG THE NORTHERN STREAM...ACROSS SOUTHERN CANADA AND
THE GREAT LAKES. WEAK DISTURBANCE TO MOVE ALONG THE NW FLOW
ACROSS THE AREA...HOWEVER MOISTURE LIMITED AND DOUBT ANYTHING
WILL REACH THE GROUND AS TIMING IS A LITTLE SLOWER WITH PASSAGE
MORE OF A DAYTIME AND THE HEAT OF THE DAY SHOULD BE ENOUGH TO
KEEP ANYTHING FROM HITTING THE GROUND. ALSO EARLY IN THE WEEK AS
THE SNOW MELTS WILL NEED TO MONITOR FOR OVERNIGHT/MORNING FOG.
RIDGE EXPANDS AS THE WEEK CONTINUES...WITH STRONG WAA ALOFT WITH
THE WESTERN PART OF THE CWA SEEING DOUBLE DIGIT 850 TEMPS.
QUESTION WILL BE HOW LONG CAN THE SNOW REMAIN AND DAMPEN TEMPS.
GUIDANCE PUSHES HIGHS INTO THE 50S AND 60S FOR WEDNESDAY AND
THURSDAY. AS IS TYPICAL WITH MANY MARCH SNOW STORMS...EXPECT THIS
SNOW NOT TO STAY LONG. ALTHOUGH WEST WINDS ON THE LIGHT
SIDE...LESS THAN 15 MPH...SHOULD BE ENOUGH TO HELP MIX WITH THE
DOWNSLOPE COMPONENT AND HAVE FOLLOWED CLOSER TO GUIDANCE FOR THE
LATER HALF OF THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 537 AM CST SAT MAR 9 2013
EXPECTING IFR/LIFR TO CONTINUE THROUGH 03Z THIS EVENING IN
SNOW...BLOWING SNOW...FOG...RAIN AND FREEZING RAIN. THEREAFTER AN
IMPROVEMENT TO MVFR/VFR SHOULD COMMENCE FROM NORTHWEST TO
SOUTHEAST. WINDS TODAY WILL INCREASE TO 36030G40KT AND DIMINISH
LATE THIS EVENING TO 34020G30KT BY 12Z SUNDAY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR
NEZ006-008-025-026-036-057-058-069.
WINTER WEATHER ADVISORY FROM NOON CST TODAY TO 7 AM CDT SUNDAY
FOR NEZ007-009-010-027>029-037-038-059-070-071.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR NEZ004-
005-022>024-035-056-094.
&&
$$
UPDATE...CDC
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...CDC
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
528 AM CST SAT MAR 9 2013
.UPDATE...
ISSUED AT 527 AM CST SAT MAR 9 2013
THE RAP13 MODEL SHOWS A SLOWER TRANSITION TO SNOW THAN THE NAM. IN
FACT THE RAP CARRIES A BROAD AREA OF FREEZING RAIN AHEAD OF THE
CHANGEOVER TO SNOW. THIS IS WELL SUPPORTED IN THE MODEL TEMPERATURE
FIELDS. SO A NEW FORECAST IS OUT WHICH HEIGHTENS THE THREAT OF
FREEZING RAIN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CST SAT MAR 9 2013
TWO ROUNDS OF THOUGHT WITH THE STORM. ONE IS FOR A STRONG FGEN
FORCED BAND OF SNOW DEVELOPING ACROSS NORTHWEST NEBRASKA TODAY
WHICH MOST SOLNS AGREE ON TO VARYING DEGREES. THE SECOND IS FOR
ANOTHER STRONG BAND OF SNOW TO DEVELOP ACROSS SOUTH CENTRAL
NEBRASKA TONIGHT AS THE FIRST BAND DECAYS. THE GEM REGIONAL AND
GFS ARE VERY FAR NORTHWEST WITH THIS BAND SIGNALING A WINTER
STORM FOR NCNTL NEB WHILE THE NAM AND ECM ARE SAFELY EAST OF THE
FCST AREA. A BLEND OF NAM...GEM AND ECM WERE USED FOR THE LATEST
FCST WHICH PROVIDES A WINTER STORM ACROSS THE NORTHWEST AND A
WINTER WEATHER ADVISORY ELSEWHERE.
HOWEVER THE NAM AND RAP SHOW A VERY STRONG BARRIER JET DEVELOPING
THIS EVENING STRETCHING NORTH-SOUTH ALONG AND WEST OF HIGHWAY 83
WHICH COULD EASILY SUPPORT A WINTER STORM IF THE FRONTOGENESIS
WAS APPROPRIATELY JUXTAPOSED. THIS IS NOT THE CASE AS THE NAM
SHOWS THE FGEN AND HEAVY QPF MOSTLY EAST OF THE FCST AREA. THE
RAP MEANWHILE NOSES THE PV1.5 ANOMALY INTO SRN NEB AT 02Z AND
DEVELOPS SOME HEAVY SNOW ACROSS SWRN NEB. THIS IS A CONCERN WHICH
WILL BE CLOSELY MONITORED.
THE STRONG BARRIER JET WILL EASILY SUPPORT 30 MPH WINDS WITH
GUSTS TO 45 MPH. IN FACT THE NAM AND RAP SHOW GUSTS TO 60 MPH AT
00Z-03Z...THE HEIGHT OF THE STORM ACROSS SWRN AND NCNTL NEB.
SO EVERYONE OUTSIDE OF THE WINTER STORM WARNING HAS BEEN PLACED
IN A WINTER WEATHER ADVISORY FOR 3 TO 5 INCHES OF SNOW AND 30 TO
45 MPH WINDS.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CST SAT MAR 9 2013
MAJOR SPRING/WINTER STORM WILL BE EXITING SUNDAY MORNING WITH
SOME LINGERING LIGHT SNOW ACROSS THE FAR EASTERN COUNTIES. WINDS
WILL CONTINUE TO BE GUSTY...AND WILL HIGHLIGHT PATCHY BLOWING
SNOW WHERE FALLING SNOW IS EXPECTED. PENDING TOTAL SNOW AND HOW
FLUFFY IT IS...MAY NEED TO CONTINUE BLOWING SNOW FURTHER WEST
EARLY SUNDAY. STILL QUESTIONING HOW FAR WEST THE HEAVY BAND OF
SNOW OVER CENTRAL NEB WILL BE.
SUNDAY HIGHS...WITH COLD HIGH PRESSURE BUILDING SOUTH ACROSS THE
NORTHERN PLAINS AND MUCH IF NOT ALL OF THE AREA EXPECTED TO SEE A
SNOW COVER...SHOULD HOLD CLOSE TO 30 DEGREES. ALTHOUGH THE SUN
WILL SPREADING FROM WEST TO EAST...WHICH SHOULD HELP TO START TO
MELT ROADWAYS.
SUNDAY NIGHT WITH AN ELONGATED HIGH ACROSS THE WESTERN
PLAINS...LIGHT WINDS AND MOSTLY CLEAR SKIES ALONG WITH SNOW
PACK...TEMPS SHOULD TANK. WIDESPREAD TEENS...WHICH MAY BE
CONSERVATIVE.
MONDAY INTO MID WEEK RIDGE BUILDS ACROSS THE WEST...WITH A TROUGH
TO PUSH ALONG THE NORTHERN STREAM...ACROSS SOUTHERN CANADA AND
THE GREAT LAKES. WEAK DISTURBANCE TO MOVE ALONG THE NW FLOW
ACROSS THE AREA...HOWEVER MOISTURE LIMITED AND DOUBT ANYTHING
WILL REACH THE GROUND AS TIMING IS A LITTLE SLOWER WITH PASSAGE
MORE OF A DAYTIME AND THE HEAT OF THE DAY SHOULD BE ENOUGH TO
KEEP ANYTHING FROM HITTING THE GROUND. ALSO EARLY IN THE WEEK AS
THE SNOW MELTS WILL NEED TO MONITOR FOR OVERNIGHT/MORNING FOG.
RIDGE EXPANDS AS THE WEEK CONTINUES...WITH STRONG WAA ALOFT WITH
THE WESTERN PART OF THE CWA SEEING DOUBLE DIGIT 850 TEMPS.
QUESTION WILL BE HOW LONG CAN THE SNOW REMAIN AND DAMPEN TEMPS.
GUIDANCE PUSHES HIGHS INTO THE 50S AND 60S FOR WEDNESDAY AND
THURSDAY. AS IS TYPICAL WITH MANY MARCH SNOW STORMS...EXPECT THIS
SNOW NOT TO STAY LONG. ALTHOUGH WEST WINDS ON THE LIGHT
SIDE...LESS THAN 15 MPH...SHOULD BE ENOUGH TO HELP MIX WITH THE
DOWNSLOPE COMPONENT AND HAVE FOLLOWED CLOSER TO GUIDANCE FOR THE
LATER HALF OF THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1153 PM CST FRI MAR 8 2013
ISOLATED THUNDERSTORMS ARE EXPECTED IN EXTREME SOUTHWEST NEBRASKA
NEAR A SURFACE TROUGH AND WARM FRONT. AT THIS TIME...IT APPEARS THAT
CELLS THAT HAVE DEVELOPED ALREADY WILL PASS A LITTLE EAST OF LBF AND
DISSIPATE BEFORE GOING VERY FAR. WIDESPREAD LIGHT RAIN OR DRIZZLE
DEVELOPING NORTH AND WEST OF BBW-LBF IS LIKELY TO SPREAD WESTWARD AS
IT MOVES NORTH...AND IT WILL PROBABLY REACH VTN 08-10Z. BY ABOUT
12Z...A BAND OF PRECIPITATION IS EXPECTED TO DEVELOP NORTH AND WEST
OF AN ONL-OGA LINE. INITIALLY...IT WILL PROBABLY BE RAIN OR A
RAIN/SNOW MIX CHANGING TO SNOW BY ABOUT 14Z AND CONTINUING THROUGH
THE DAY SATURDAY. IN CENTRAL THROUGH SOUTHWEST NEBRASKA...SNOW IS
NOT EXPECTED BEFORE 00Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR
NEZ006-008-025-026-036-057-058-069.
WINTER WEATHER ADVISORY FROM NOON CST TODAY TO 7 AM CDT SUNDAY
FOR NEZ007-009-010-027>029-037-038-059-070-071.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ SUNDAY FOR NEZ004-
005-022>024-035-056-094.
&&
$$
UPDATE...CDC
SHORT TERM...CDC
LONG TERM...MASEK
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS RALEIGH NC
203 AM EDT SUN MAR 10 2013
.SYNOPSIS...
HIGH PRESSURE ALONG THE EAST COAST WILL DRIFT EASTWARD IN ADVANCE OF
A COLD FRONT THAT WILL CROSS CENTRAL NC EARLY TUE.
&&
.NEAR TERM /TONIGHT/...
AS OF 915 PM SUNDAY...
REST OF TONIGHT: BIGGEST CHALLENGE TONIGHT IS HOW MUCH STRATUS WILL
FORM -- IF ANY -- AND WHERE IT WILL BE MOST WIDESPREAD. HIGH
PRESSURE CENTERED JUST OFF THE MAINE COAST AND EXTENDING DOWN THE
EASTERN SEABOARD ACCORDING TO THE LATEST SURFACE ANALYSIS WILL SLIP
SLOWLY EASTWARD OFF THE COAST TONIGHT... RESULTING IN A SLOW BUT
STEADY INFLUX OF ATLANTIC-SOURCE NEAR-SURFACE MOISTURE INTO NC AS
WINDS SWING AROUND TO SOUTHEASTERLY. SURFACE DEW POINTS ACROSS
CENTRAL NC HAVE VARIED WIDELY FOR THE LAST SEVERAL HOURS... FROM
15-20 EAST/CENTRAL TO 25-34 WEST LATE THIS AFTERNOON... AND THIS
WIDE RANGE REMAINS ALBEIT WITH A MARKED INCREASE INTO THE 20S AND
LOW 30S IN THE COASTAL PLAIN... PUSHING THE VALUES IN THE TEENS UP
INTO THE NORTHEAST PIEDMONT. DEW POINTS IN THE UPPER 30S AND 40S ARE
NOT FAR AWAY... RIGHT AT THE COAST AND JUST OFFSHORE... AND I SEE
NOTHING TO SUGGEST THAT THIS HIGHER LOW-LEVEL MOISTURE WILL NOT
CONTINUE TO SURGE INTO THE COASTAL PLAIN OVERNIGHT. THE LATEST RUNS
OF THE RAP SUPPORT THIS ONSHORE SURGE OF MOISTURE... AS DO RECENT
HRRR RUNS WHICH DEPICT RAPID DEVELOPMENT OF LOW CIGS ALONG AND EAST
OF I-95 BEFORE 09Z. WORKING AGAINST SUCH A SCENARIO IS THE RESIDENT
DRY AIR NOTED ON AREA SOUNDINGS... AS LOW LEVELS ARE MORE MOIST AT
MHX/CHS THAN AT GSO BUT NOT INCREDIBLY SO. BUT GIVEN THE STABLE
NEAR-SURFACE LAYER... THE AFTERNOON ABUNDANCE OF STRATOCU JUST OFF
THE CAROLINA COAST... AND WITH A MULTITUDE OF MODELS (INCLUDING BUFR
SOUNDINGS FROM THE NAM AND GFS) SHOWING LOW STRATUS FORMING BY
MORNING ESPECIALLY IN THE EAST... WILL INCREASE SKY COVER ESPECIALLY
IN THE EASTERN HALF OF THE CWA. MOISTURE REMAINS ELEVATED IN THE
WESTERN PIEDMONT AS WELL... AND UPSLOPE FLOW MAY RESULT IN AREAS OF
STRATUS HERE AS WELL... ALTHOUGH TRAJECTORIES SUGGEST THAT THE
ISOLATED POCKET OF DRY SURFACE AIR NOW FOUND OVER INTERIOR SOUTHEAST
NC AND NORTHEAST SC WILL TRANSLATE INTO THIS AREA... LIMITING
STRATUS FORMATION SOMEWHAT. TEMPS HAVE ALREADY DROPPED INTO THE 40S
IN ISOLATED SPOTS BUT 50S REMAIN WIDESPREAD ENOUGH TO JUSTIFY A
SLIGHT UPWARD TICK IN LOWS TONIGHT... GIVEN THE ANTICIPATED CLOUD
DEVELOPMENT. LOWS 39-46. -GIH
&&
.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 225 PM SUNDAY...
LEADING EDGE OF A 45-50KT SOUTHERLY LOW-LEVEL JET EMBEDDED IN THE
BROAD WARM AIR CONVEYOR BELT DOWNSTREAM OF THE SYSTEM WILL BEGIN TO
ADVECT GULF MOISTURE NORTHWARD LATE MONDAY AFTERNOON...WHICH WILL
RESULT IN SCATTERED SHOWERS BREAKING OUT OVER THE AREA LATE MONDAY
AFTERNOON/EARLY EVENING. DEEP LAYER FORCING VIA DIFFLUENT FLOW
ALOFT ASSOCIATED WITH A COUPLED JET STRUCTURE ATOP STRONG LOW-LEVEL
MOISTURE FLUX CONVERGENCE ALONG THE SOUTHERLY LOW-LEVEL JET
WILL ARRIVE FROM THE WEST AOA MIDNIGHT MONDAY NIGHT WITH
SIGNIFICANT-WIDESPREAD(CATEGORICAL)CONVECTIVE SHOWERS SPREADING WEST
TO EAST THROUGH THE AREA THROUGH 15Z TUESDAY MORNING BEFORE THIS
SUPPORT MOVES OFFSHORE. THE LOW-LEVEL JET AND ATTENDANT LINE OF
CONVECTION WILL SERVE AS THE EFFECTIVE FRONT WITH ONLY AN ISOLATED
SHOWER EXPECTED WITH THE ACTUAL TRAILING SFC COLD FRONT AS IT MOVES
THROUGH THE AREA BETWEEN 15 TO 21Z TUESDAY. A SOLID ONE QUARTER TO
ONE HALF INCH OF RAINFALL LOOKS TO BE IN ORDER FOR ALL OF CENTRAL
NC.
THUNDER/SEVERE THREAT:
WITH THE STRONG TROUGH DYNAMICS AND LOW-LEVEL KINEMATIC
FIELDS TRAVERSING THE CAROLINAS BETWEEN 06 TO 15Z TUESDAY...
WEAK TO MODEST MID-LEVEL LAPSE RATES OF 5.5 TO 6.0 C/KM--NOCTURNAL
BOUNDARY LAYER COOLING OVERNIGHT ALONG WITH RATHER WIDESPREAD
LOW-LEVEL CLOUD COVER ACROSS THE AREA THROUGH MIDDAY TUESDAY
WILL RESULT IN MEASLY INSTABILITY (100-200 J/KG MUCAPE)ACROSS
EASTERN NC. SO WHILE NOT ZERO...BOTH THUNDER AND A SEVERE THREAT ARE
VERY LOW. WILL NOT INCLUDE A MENTION OF THUNDER AT THIS TIME.
TEMPERATURES:
MILD OVERNIGHT LOWS MONDAY NIGHT GIVEN WIDESPREAD RAIN AND CLOUDS.
LOWS IN THE LOWER 50S NW TO MID-UPPER 50S SOUTHEAST. NOT MUCH
DIFFERENCE IN HIGHS TEMPERATURES FROM MONDAY TO TUESDAY WITH CAA
DELAYED UNTIL TUESDAY NIGHT. AS SUCH...CLOUD COVER WILL BE THE MAIN
DETERMINING FACTOR. HIGHS BOTH DAYS IN THE LOWER 60S NW TO NEAR 70
SOUTHEAST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
AS OF 225 PM SUNDAY...
TO START THE LONG TERM PERIOD...THE COLD FRONT AND ASSOCIATED PRECIP
ARE EXPECTED TO BE EAST OF THE AREA BY EARLY TUESDAY EVENING...WITH
ANY LINGERING CLOUDS ACROSS THE EASTERN PORTIONS OF THE FORECAST
AREA CLEARING SHORTLY AFTER. COLD AIR ADVECTION BEHIND THE DEPARTING
FRONT WILL LEAD TO COOLER OVERNIGHT LOWS...GENERALLY IN THE MID TO
UPPER 30S. THEN...MUCH OF THE PERIOD IS EXPECTED TO BE DOMINATED BY
A BROAD UPPER TROUGH. THIS WILL RESULT IN BELOW NORMAL TEMPS...
ESPECIALLY WED AND THU AS SOME COLD AIR ADVECTION CONTINUES. TEMPS
SHOULD REBOUND SLIGHTLY TO NEAR NORMAL BY THE END OF THE WEEK AND
INTO THE WEEKEND AS HEIGHTS RISE SOME. WITH REGARDS TO ANY PRECIP...
WITH NORTHWESTERLY FLOW ALOFT PERSISTING ACROSS OUR REGION...MODELS
CONTINUE TO PROG SEVERAL DISTURBANCES/CLIPPERS MOVING SOUTHEAST
WITHIN THIS FLOW. HOWEVER...UNCERTAINTY REMAINS HIGH WITH RESPECT TO
EXACT TRACK OF THESE (AND TIMING IN GENERAL) AND WITH MOISTURE
REMAINING RATHER LIMITED...WILL MAINTAIN A DRY FORECAST THROUGH AT
LEAST THE END OF THE WEEK. UNCERTAINTY INCREASES EVEN MORE BY THE
WEEKEND AS MODELS ARE SHOWING A BACKDOOR FRONT IMPACTING THE AREA
(TO VARYING DEGREES). MOISTURE IS PROGGED TO BEGIN TO INCREASE
DURING THIS TIME FRAME AS WELL AND THEREFORE WILL GO AHEAD AND
INTRODUCE SLIGHT CHANCE POPS FOR THE WEEKEND...ALTHOUGH CONFIDENCE
IS FAIRLY LOW.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AS OF 201 AM MONDAY...
24-HR TAF PERIOD:
HIGH CLOUDS INCREASING AHEAD OF THE COLD FRONT APPROACHING THE
AREA... INDICATIONS ARE THAT INCREASING SOUTHERLY FLOW AND MOISTURE
WILL RESULT IN THE FORMATION OF LOW STRATUS IN THE EARLY MORNING
OVER THE AREA... AND DEWPOINTS ACROSS THE COASTAL PLAIN AND PIEDMONT
HAVE RISEN OVER THE PAST FEW HOURS TO THE MID AND UPPER 20S. CLOUDY
CONDITIONS WILL CONTINUE THROUGH THE DAY...WITH CIGS RISING IN THE
MORNING HOURS TO MVFR AFTER 12Z. RAIN CHANCES WILL INCREASE LATE IN
THE 24 HOUR PERIOD... AFFECTING INT AND GSO FIRST BEFORE MOVING EAST.
LOOKING AHEAD:
RAIN WILL BE EXITING THE REGION AFTER 18Z TUESDAY... BRINGING A
RETURN TO VFR CONDITIONS. WINDS GUSTING 15 TO 20KTS WILL BE POSSIBLE
DURING THE AFTERNOON HOURS ON TUESDAY AND WEDNESDAY. VFR CONDITIONS
REMAIN LIKELY THROUGH THE REST OF THE WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...HARTFIELD
SHORT TERM..CBL
LONG TERM...KRR
AVIATION...SEC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1100 AM EDT MON MAR 11 2013
.UPDATE...
ISSUED AT 1059 AM EDT MON MAR 11 2013
12Z RAOBS/LATEST STLT IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR LO
OVER SW WI LIFTING NEWD AS DISTURBANCE DIGS INTO THE NRN PLAINS. DRY
SLOT IN ADVANCE OF THIS DISTURBANCE HAS OVERSRPEAD MUCH OF THE
SCNTRL AND ERN CWA...LIMITING THE PCPN IN THESE AREAS TO SCT -SHSN
OR EVEN -SHRA OVER THE E WHERE SFC TEMPS ARE NOW ABV 32. BUT WET SN
STRETCHING FM SE MN THRU WCENTRAL WI INTO THE W HALF OF UPR MI ON
CYC SIDE OF H7 LO TRACK.
A FEW CHGS TO HEADLINES FOR NOW...PLAN TO CANX GOING WRNG FOR ALGER
COUNTY AS DRY SLOT HAS LIFTED THRU THIS AREA. ALTHOUGH THERE COULD
BE SOME SN OVER THE FAR W PORTION OF THE COUNTY...BULK OF THIS AREA
WL SEE ONLY SCT -SHSN THRU THE DAY. MQT COUNTY WL BE ON THE ACYC
SIDE OF THE H7 LO TRACK AS WELL...BUT PERSISTENT NE SFC WIND IS
FVRBL FOR LINGERING WET SN OVER THE HIER TERRAIN. WL CONT GOING
HEADLINES FOR THE WRN ZNS...WHICH WL BE MOST IMPACTED BY SN UNDER
THE DEFORMATION ZN.
SINCE TEMPS ARE ABV 32 WHERE RA IS FALLING OVER THE E FM NEWBERRY TO
MANISTIQUE...TOOK OUT MENTION OF FZRA. ALSO ADDED MENTION OF PATCHY
FOG WITH LLVL MSTR UNDER THE DRY SLOT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 509 AM EDT MON MAR 11 2013
UPPER AIR PATTERN CONSISTS OF A CLOSED 500 MB LOW OVER SOUTHERN
IOWA WITH AN ASSOCIATED TROUGH OVER THE CENTRAL PLAINS. THIS
CLOSED LOW WILL CONTINUE TO HEAD NORTHEAST TODAY AND OPEN UP. THIS
TROUGH WILL THEN TAKE ON A NEGATIVE TILT OVER THE UPPER GREAT LAKES.
THIS TROUGH MOVES OUT TONIGHT.
NAM BRINGS IN SOME 850-500 MB Q-VECTOR CONVERGENCE OVER THE AREA
WITH DEEP MOISTURE TODAY BEFORE THE STRONG Q-VECTOR CONVERGENCE
MOVES OUT BY TONIGHT. NAM HAS SOME ISENTROPIC LIFT ON I280OK-I295K
WITH MOISTURE THIS MORNING THAT MOVES OUT BY THIS EVENING.
BUSY MORNING DEALING WITH ALL SORTS OF WEATHER AND MIXED PCPN. HEAVY
SNOW CONTINUES ACROSS THE CENTRAL AND WESTERN CWA WITH SOME RAIN
MIXED IN WITH SOME FREEZING RAIN OVER THE SOUTH AND EAST. LEAD
SHORTWAVE ON WATER VAPOR IS MOVING THROUGH AND THERE IS A BREAK IN
PCPN THAT IS DEVELOPING ACROSS NE WI AND THE FAR SOUTHERN U.P.
ASSOCIATED WITH A DRY SLOT. THIS DRY SLOT IS HEADING NORTH AND COULD
END UP ENDING THE PCPN SOONER THAN EXPECTED EXCEPT IN UPSLOPE AREAS.
AM A LITTLE CONCERNED THAT THE DRY SLOT WOULD HAVE SOME FREEZING
DRIZZLE ASSOCIATED WITH IT. FOR THIS REASON...KEPT UP ALL HEADLINES
FOR NOW AND WILL PROBABLY HAVE TO CANCEL SOME OF THEM EARLIER IF IT
APPARENT THAT THE HEAVIEST PCPN IS DONE ALREADY. OTHERWISE...KEPT IN
FREEZING RAIN AND RAIN THIS MORNING ACROSS THE SOUTH AND EAST WITH
SNOW IN THE WEST AND QUICKLY LOOKED AT A FEW SOUNDINGS FOR ISQ...ESC
AND ERY OFF OF BUFKIT AND CONFIRMED PREVIOUS THINKING OF MIXED PCPN
THIS MORNING. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE
PREVIOUS FORECAST EXCEPT PUSH TIMING UP FOR HEAVIER PCPN MOVING OUT
THIS MORNING.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 509 AM EDT MON MAR 11 2013
LOW PRESSURE SYSTEM THAT WILL BE AFFECTING THE AREA TODAY AND
TONIGHT WILL BE EXITING THROUGH NORTHWEST QUEBEC ON TUESDAY...BUT
WILL LINGER A SURFACE TROUGH BACK TO THE SOUTHEAST ACROSS UPPER
MICHIGAN. THIS...COMBINED WITH THE UPPER TROUGH OVER THE AREA WILL
LEAD TO LAKE EFFECT/ENHANCED SNOW SHOWERS OVER THE AREA ON TUESDAY
INTO TUESDAY NIGHT. 850MB TEMPS AROUND -13C TO -16C WILL PROVIDE
ENOUGH OVER LAKE INSTABILITY AND WHEN COMBINED WITH THE DEEPER
MOISTURE LINGERING UNDER THE UPPER TROUGH OVER THE GREAT LAKES
REGION WILL LEAD TO THE HEAVIEST SNOW IN THE NORTH-NORTHWEST WIND
SNOW BELTS. LATEST TRENDS IN THE MODELS ARE INDICATING THE DRIER AIR
ALOFT TO BE A LITTLE FARTHER WEST FOR TUESDAY AND THINK THERE WILL
BE A BETTER CHANCE FOR SNOW OVER THE WESTERN PORTIONS OF THE CWA
THAN PREVIOUS THOUGHT. WITH THE GREATER CONFIDENCE ON THE SNOW ON
TUESDAY...HAVE BUMPED POPS NEAR LAKE SUPERIOR TO DEFINITE VALUES
WITH THE HIGHEST POPS OVER THE KEWEENAW AND NORTH CENTRAL UPPER
MICHIGAN. FARTHER INLAND...WOULD EXPECT SCATTERED SNOW SHOWERS WITH
THE ABUNDANT MOISTURE AND CONTINUING UPWARD MOTION UNDER THE UPPER
TROUGH...ESPECIALLY ON TUESDAY AFTERNOON. SNOWFALL AMOUNTS DURING
THE DAY ON TUESDAY WILL BE IN THE 1-4 INCH RANGE ACROSS MUCH OF THE
AREA...WITH THE HIGHEST AMOUNTS OVER THE FAVORED LOCATIONS NEAR LAKE
SUPERIOR. IN ADDITION...INCREASING WINDS AND A TREND TOWARDS MORE
FLUFFY SNOW SHOULD LEAD TO BLOWING SNOW FOR AREAS NEAR LAKE SUPERIOR
TUESDAY AFTERNOON INTO TUESDAY TONIGHT. THESE TWO FACTORS MAY BE
ENOUGH FOR A FUTURE ADVISORY FOR THE COUNTIES NEAR LAKE SUPERIOR AND
WILL MENTION THE LIGHT/MODERATE SNOW IN THE HWO.
WITH THE UPPER TROUGH STARTING TO SHIFT TO THE EAST ON TUESDAY NIGHT
AND INTO WEDNESDAY...DRIER AIR WILL START TO WORK INTO THE UPPER
GREAT LAKES AREA AND DECREASE THE INTENSITY OF THE SNOW SHOWERS.
COMPARED TO 24HRS AGO...THE MODELS HAVE SHOWN A MUCH QUICKER DRYING
TREND AND HAVE FOLLOWED SUIT WITH POPS. LATEST IDEA FROM THE NAM/GFS
IS FOR THE LAKE EFFECT SNOW TO BE DONE BY WEDNESDAY AFTERNOON. THERE
MAY BE A FEW SNOW SHOWERS REDEVELOPING OVER THE EAST LATE IN THE
AFTERNOON OR EARLY EVENING AS THERE ARE HINTS OF A SECOND AREA OF
925-850MB MOISTURE MOVING THROUGH WITH FAVORABLE 850MB TEMPS OF
-13C.
THE UPPER RIDGE WILL PUSH IN ON WEDNESDAY NIGHT AND ALLOW A SURFACE
HIGH TO MOVE INTO THE AREA. ANY ISOLATED SNOW SHOWERS ON WEDNESDAY
EVENING SHOULD QUICKLY COME TO AN END AS THE SMALL POCKET OF
MOISTURE DEPARTS. WITH THE DRY AIR AND WEAKENING WINDS WITH THE
APPROACHING HIGH...HAVE TRENDED TEMPS COLDER ON WEDNESDAY NIGHT.
CURRENT FORECAST HAS INTERIOR WEST TEMPS IN THE LOW SINGLE DIGITS
AND THERE IS THE POTENTIAL FOR SOME LOCATIONS TO FALL BELOW BELOW
ZERO.
WITH AN UPPER RIDGE OVER THE WESTERN CONUS...AREA WILL BE UNDER
NORTHWEST FLOW ALOFT FROM THURSDAY THROUGH THE WEEKEND. THIS LEADS
TO THE POTENTIAL FOR SHORTWAVES AND WEAK LOW PRESSURE SYSTEMS TO
QUICKLY SLIDE ACROSS THE AREA. THERE ARE STILL HINTS OF A SHORTWAVE
FOR THE THURSDAY INTO THURSDAY NIGHT...BUT LATEST TRENDS HAVE THAT
SLIDING TO THE SOUTHWEST OF THE CWA. BASED OFF THE 00Z RUNS...THE
BEST POTENTIAL FOR A SHORTWAVE TO AFFECT THE AREA WILL BE ON
SATURDAY AND WILL TREND TOWARDS CHANCE POPS FOR THAT PERIOD.
HIGHS TUESDAY AND WEDNESDAY WILL BE SIMILAR TO VALUES YOU WOULD
EXPECT TO SEE A MONTH AGO /MID 20S/. THERE WILL BE A SLIGHT WARM UP
FOR THE SECOND HALF OF THE WEEK AND INTO THE WEEKEND...BUT HIGHS
SHOULD STILL STAY AT OR SLIGHTLY BELOW NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 714 AM EDT MON MAR 11 2013
WINTER STORM TRACKING INTO THE UPPER GREAT LAKES WILL CONTINUE TO BE
THE DOMINANT FEATURE FOR MOST OF THIS FCST PERIOD. ON THE WESTERN
FRINGE OF THE STORM SYSTEM...IFR CONDITIONS SHOULD PREVAIL AT KIWD
THRU THE MORNING HRS BEFORE CONDITIONS IMPROVE TO MVFR THROUGH THE
REST OF THE PERIOD THERE. HEAVIER SNOW WILL IMPACT KCMX AND
ESPECIALLY KSAW...LIKELY RESULTING IN IFR CONDITIONS THRU MUCH OF
THE MORNING HRS. N/NE WINDS GUSTING 20-30KT...STRONGEST AT KSAW
GIVEN FAVORABLE WIND DIRECTION...WILL PRODUCE BLSN AS WELL. THIS
AFTN...EXPECT SOME IMPROVEMENT TO MVFR AT KCMX/KSAW WHERE THINGS
WILL STAY THROUGH TONIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 509 AM EDT MON MAR 11 2013
DECIDED TO GO WITH A GALE WARNING FOR EASTERN LAKE SUPERIOR THIS
MORNING AS THE SFC PRESSURE GRADIENT TIGHTENS AS A LOW MOVES THROUGH
NORTHERN LAKE MICHIGAN INTO NORTHERN LAKE HURON TODAY. FREQUENT
GUSTS UP TO 35 KNOTS WILL BE EXPECTED THIS MORNING. WINDS CRANK UP
AGAIN TO CLOSE TO GALES ACROSS EASTERN LAKE SUPERIOR TUE NIGHT.
AFTER THAT...HIGH PRESSURE BUILDS IN AND THE WINDS WILL DIMINISH
THROUGH THE REST OF THE FORECAST PERIOD. THERE WILL BE SOME FREEZING
SPRAY OUT ON LAKE SUPERIOR.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER STORM WARNING UNTIL 11 PM EDT THIS EVENING FOR MIZ004-005-
084.
WINTER WEATHER ADVISORY UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING
FOR MIZ002-009.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT TUESDAY FOR MIZ001-003.
LAKE SUPERIOR...
GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LSZ266-267.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...KC
SHORT TERM...07
LONG TERM...SRF
AVIATION...07
MARINE...07
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
724 AM CDT MON MAR 11 2013
.SYNOPSIS...
ISSUED AT 404 AM CDT MON MAR 11 2013
WATER VAPOR IMAGERY AT 08Z SHOWED A DEEP TROUGH OVER THE CENTRAL
CONUS WHICH EXTENDED INTO BAJA CALIFORNIA...WITH THE UPPER LEVEL LOW
CENTERED OVER IOWA. SNOW CONTINUED TO FALL WITH THIS SYSTEM OVER
EASTERN NEBRASKA EARLY THIS MORNING...HOWEVER MOST IMPACTS HAD
SHIFTED EAST OF THE STATE. STRONG RIDGING WAS OBSERVED DOWNSTREAM
OVER THE EAST COAST...WHILE ANOTHER BROAD RIDGE WAS SEEN OVER THE
EASTERN PACIFIC AND WESTERN CONUS. THERE WAS A WEAK SHORTWAVE
TROUGH OVER MONTANA THIS MORNING AS TOP OF THE RIDGE WAS FAIRLY
FLATTENED. AT THE SURFACE...THE PRESSURE GRADIENT HAD FINALLY
WEAKENED AS THE SURFACE LOW WITH THE SYSTEM TO THE EAST PULLED OFF
INTO ILLINOIS AND WISCONSIN. THIS LEFT WINDS TO DIMINISH
OVERNIGHT...WHILE A SURFACE TROUGH WAS ANALYZED ON THE LEE SIDE OF
THE ROCKIES WITH BREEZY WESTERLY WINDS IN ITS WAKE. WITH WEAK HIGH
PRESSURE OVER THE FORECAST AREA...TEMPERATURES OVERNIGHT HAVE
DROPPED SIGNIFICANTLY...INTO THE SINGLE DIGITS AND TEENS.
&&
.UPDATE...
ISSUED AT 715 AM CDT MON MAR 11 2013
A NEW FORECAST IS OUT. LOOKING AT THE RAP MODEL SOUNDINGS AND THE
K INDEXES OF ALL MODELS SUGGESTS REASONABLE POTENTIAL FOR
CONVECTION THIS AFTERNOON...MAINLY OFF THE BLACK HILLS AND IN THE
PANHANDLE WHERE MOISTURE WILL BE DEEPEST AND LAPSE RATES STEEPEST.
WE MAY EVEN SEE A BREAKAWAY STORM MOVE AS FAR SOUTH AS I-80 LATE
THIS AFTN OR THIS EVENING. THE NAM INDICATED POTENTIAL FOR TSTMS
BUT GIVEN THE ISOLATED COVERAGE IT IS PROBABLY NOT WORTH MENTION.
OTHERWISE RAIN AND SNOW SHOWERS UNTIL EARLY EVENING THEN SNOW
SHOWERS.
WINDS STAY UP TONIGHT SO LOWS SHOULD BE IN THE 20S MOST AREAS. THE
MODELS ARE SUGGESTING A BLEND OF PACIFIC AND ARCTIC MOVING IN
TONIGHT AND HOLDING ON THROUGH TUESDAY. HIGH TEMPERATURES TUESDAY
HAVE BEEN MARKED DOWN TO 30S TO LOWER 40S AS SUGGESTED BY A
MULTIMODEL BLEND OF BIAS DATA.
WINDS TODAY AND TUESDAY WILL REACH 20 TO 30 MPH...ACROSS THE WEST
TODAY AND THE NORTHEAST TUESDAY.
&&
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 404 AM CDT MON MAR 11 2013
A MULTIMODEL BLEND OF THE GEM...NAM...GFS AND ECM WHICH ARE ALL
PRETTY CLOSE WITH LOW PRESSURE DROPPING THROUGH THE MISSOURI BASIN
SETTING OFF ISOLATED RAIN OR SNOW SHOWERS THIS AFTERNOON. FARTHER
WEST...LAPSE RATES STEEPEN LATE THIS AFTERNOON AND THIS EVENING. A
COLD FRONT DROPS THROUGH THE HIGH PLAINS ACTING AS A FOCUS FOR RAIN
AND SNOW SHOWERS.
WINDS INCREASE TO 15 TO 30 MPH THIS AFTERNOON AND REMAIN
SUFFICIENTLY STRONG TO PREVENT THE DEVELOPMENT OF A SFC INVERSION
TONIGHT. SO TEMPS TONIGHT SHOULD REMAIN MOSTLY IN THE 20S...A FEW
TEENS IN THE NORTHWEST WHERE HIGH PRESSURE WILL SETTLE IN SOMEWHAT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 404 AM CDT MON MAR 11 2013
THE FORECAST FOCUS THROUGH THIS PERIOD IS WITH TEMPERATURES...AS
WELL AS PRECIPITATION CHANCES THROUGH THE WEEKEND.
THE TUESDAY THROUGH FRIDAY PERIOD IS FAIRLY STRAIGHT FORWARD THIS
FORECAST CYCLE AS MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE
UPPER LEVEL PATTERN AND SURFACE FEATURES.
THE RIDGE OFF THE EAST COAST WILL STAY FIRMLY IN PLACE THROUGH
MID-WEEK WHICH WILL KEEP AN UPPER LEVEL TROUGH CENTERED OVER THE
MISSISSIPPI AND OHIO VALLEYS. MEANWHILE...ENERGY ASSOCIATED WITH THE
SHORTWAVE TROUGH CURRENTLY OVER MONTANA WILL BE MOVING OUT OF THE
NORTHERN AND CENTRAL PLAINS ON TUESDAY AND INTO THE PRIMARY TROUGH
TO THE EAST. ANY PRECIPITATION EXPECTED FOR MONDAY NIGHT SHOULD
END BY TUESDAY MORNING AS ANY FORCING FOR PRECIPITATION
DEVELOPMENT WANES ACROSS THE LOCAL AREA. ALTHOUGH THE FORECAST
AREA WILL BE IN NORTHWEST FLOW BEHIND THIS SHORTWAVE...SLIGHT WARM
AIR ADVECTION WILL BE ONGOING THROUGH THE DAY...AND WITH SKIES
EXPECTED TO CLEAR AS HIGH PRESSURE BUILD IN...TEMPERATURES WILL BE
ON A WARMING TREND. SHOULD STILL SEE IMPACTS ON HIGHS ON TUESDAY
FROM THE SNOWPACK...WHICH IS QUITE SUBSTANTIAL IN PARTS OF THE
FORECAST AREA.
THE UPPER LEVEL TROUGH OVER THE OHIO VALLEY WILL FINALLY SHIFT
FURTHER EASTWARD THROUGH THURSDAY ALLOWING THE RIDGE OVER THE WEST
TO BUILD INTO THE PLAINS. THIS WILL BRING SIGNIFICANT WARM AIR
ADVECTION TO THE REGION AS TEMPERATURES AT 850MB ARE BEING SHOWN
TO RISE INTO THE MID AND UPPER TEENS BY FRIDAY EVENING. SNOW MELT
WILL BE IN FULL SWING BY WEDNESDAY AND BY THURSDAY AND FRIDAY
DON/T EXPECT MUCH IMPACT ON TEMPERATURES. ALTHOUGH MODELS AREN/T
SHOWING REAL STRONG WINDS WEDNESDAY THROUGH FRIDAY...THOUGHTS ARE
THAT WITH THE WARMING EXPECTED...WILL GET DECENT MIXING TO BRING
DOWN SOME STRONGER WINDS FROM ALOFT SO DID INCREASE THE WIND
SPEEDS SLIGHTLY. DIDN/T GO QUITE AS WARM AS SOME MODELS WOULD
SUGGEST...AS SOME GUIDANCE WAS GIVING MID TO UPPER 70S FOR FRIDAY.
STUCK WITH UPPER 50S AND 60S FOR THURSDAY AND 60S TO LOW 70S FOR
FRIDAY.
THINGS WILL COOL OFF FOR THE WEEKEND AS THE MODELS ARE SHOWING A
SWITCH IN THE UPPER LEVEL PATTERN. THIS BEING SAID...THERE ARE
CONSIDERABLE DIFFERENCES IN THE MODEL SOLUTIONS THROUGH THE
WEEKEND SO CONFIDENCE ON THIS PORTION OF THE FORECAST IS FAIRLY
LOW. THERE LOOKS TO BE A CHANCE FOR SOME PRECIPITATION ACROSS THE
AREA AT SOME POINT DURING THE WEEKEND...BUT WITH THE
INCONSISTENCIES AND LOW CONFIDENCE IN MODEL SOLUTIONS...TRIED TO
PICK OUT THE PERIODS AND LOCATIONS WITH THE HIGHER PROBABILITIES TO
INCLUDE PRECIPITATION CHANCES IN THE FORECAST AT THIS POINT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 620 AM CDT MON MAR 11 2013
VFR IS GENERALLY EXPECTED TODAY AND TONIGHT AS A MIX OF MID AND
HIGH CLOUDS MOVE SOUTHEAST OFF THE HIGH PLAINS. THERE IS
OPPORTUNITY FOR MVFR CIGS IN ISOLATED TO SCATTERED RAIN AND SNOW
SHOWERS...MAINLY LATE THIS AFTERNOON AND THIS EVENING ACROSS NRN
AND WRN NEB. THE MODELS OFFER SOME DIVERSE SOLNS TO THIS EVENT.
SOME DEVELOP CONVECTION ACROSS NRN NEB AROUND NOON WHILE OTHERS
WAIT TILL LATE AFTERNOON AND SOME SOLNS SHOW NO CONVECTION AT ALL
ACROSS NRN NEB.
THERE IS A GOOD CONSENSUS FOR ACTIVITY DEVELOPING OFF THE BLACK
HILLS LATE THIS AFTERNOON AND ACROSS THE NEB PANHANDLE. THIS
ACTIVITY WILL MOVE SOUTH SOUTHEAST. IN FACT THERE COULD EVEN BE AN
ISOLATED LIGHTNING STRIKE OR TWO ACROSS SHERIDAN AND CHERRY
COUNTIES LATE THIS AFTERNOON.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CDC
SYNOPSIS...BROOKS
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
656 AM EDT MON MAR 11 2013
.SYNOPSIS...
MOIST SOUTHERLY FLOW AHEAD OF A COLD FRONT WILL BRING WIDESPREAD
SHOWERS TO THE REGION TODAY. THE COLD FRONT WILL PUSH EAST TONIGHT
WHICH WILL SIGNAL THE END OF WIDESPREAD PRECIPITATION. A COLD
UPPER LEVEL TROUGH WILL DIG SOUTHEAST INTO THE GREAT LAKES AND
OHIO VALLEY TUESDAY INTO WEDNESDAY. THIS PATTERN WILL BRING A
THREAT OF RAIN AND SNOW SHOWERS ALONG WITH BELOW NORMAL TEMPERATURES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
NWP MODELS WERE IN FAIRLY DECENT AGREEMENT IN TERMS OF SYNOPTIC
SCALE FORCING AND TIMING OF FEATURES. HAVE USED A BLEND OF THE
NAM...GFS AND THE RAP FOR THE NEAR TERM FORECAST.
PRECIPITATION ACROSS THE REGION TODAY WILL COME IN TWO SEPARATE
WAVES. THE FIRST BOUT OF SHOWERS WILL ACCOMPANY A MOIST...LOW
LEVEL JET WHICH WILL PUSH SOUTHWEST TO NORTHEAST THROUGH THE
MORNING AND EARLY AFTERNOON HOURS. AS THIS SHIFTS EAST...AN UPR
LVL S/WV AND ACCOMPANYING SFC COLD FRONT WILL SWING THROUGH THE
WESTERN ZONES THIS AFTERNOON...PUSHING THROUGH THE EASTERN ZONES
BY EARLY EVENING. THIS FEATURE WILL ALSO BRING ANOTHER ROUND OF
SHOWERS. RAINFALL WITH THE FIRST WAVE IS EXPECTED TO BE THE
HEAVIEST WITH 0,50 TO 1.25 INCHES OF RAIN EXPECTED. THERE CONTINUES
TO BE SOME CONCERN FOR FLOODING GIVEN THE RECENT SNOW MELT AND
MOIST TO NEARLY SATURATED GROUND...PARTICULARLY IN THE
WHITEWATER...MIAMI...AND UPPER SCIOTO RIVER BASINS. ATTM...BELIEVE
WIDESPREAD FLOODING IS NOT EXPECTED GIVEN STEADY BUT PROGRESSIVE
MOVEMENT TO THE EAST OF THE FIRST BATCH OF SHOWERS. HOWEVER...WILL
CONTINUE TO MONITOR FOR ANY POTENTIAL FLOOD ADVISORIES GIVEN HIGH
STREAM LEVELS PER USGS WEB SITE AND SATURATED SOILS. WILL ALSO
HIGHLIGHT THIS THREAT IN THE HWO PRODUCT. WILL ALSO MONITOR THE
LINE OF SHOWERS EXPECTED WITH FRONTAL PASSAGE AS SOME MODELS
INDICATE THAT SOME GUSTY WINDS MAY OCCUR. AS FOR TEMPERATURES...THEY
WILL BE TRICKY GIVEN PERSISTENT RAIN ACRS THE WEST BUT LATE
ARRIVING IN THE FAR EAST. HAVE HIGHS RANGING FROM THE LOWER 50S
WEST TO THE UPPER 50S FAR EAST. HOWEVER...IF RAIN IS SLOWER TO
ARRIVE IN THE FAR EAST...TEMPERATURES MAY WARM INTO THE 60S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
AFOREMENTIONED COLD FRONT AND S/WV WILL MOVE OFF TO THE EAST THIS
EVENING WHICH WILL SIGNAL THE END OF WIDESPREAD PCPN. TEMPERATURES
WILL FALL OVERNIGHT IN THE CAA PATTERN BEHIND THE FRONT. MODELS
CONTINUE TO SUGGEST THAT AN EMBEDDED DISTURBANCE WILL APPROACH THE
AREA FROM THE WEST LATE. THIS MAY TRIGGER A FEW SNOW SHOWERS ACRS
THE NRN ZONES BY MORNING.
FOR THE PERIOD TUESDAY INTO WEDNESDAY...A COLD UPR LEVEL TROUGH IS
FORECAST TO DIG SOUTHEAST INTO THE GREAT LAKES AND OHIO VALLEY.
SKIES ON TUESDAY WILL BE MOSTLY CLOUDY WITH PERHAPS A FEW LIGHT
RAIN AND SNOW SHOWERS ACROSS THE NORTH IN THE CAA PATTERN WHICH
WILL BRING SOME LOW LEVEL INSTABILITY. AN EMBEDDED S/WV ROTATING
AROUND THE LOW IS EXPECTED TO PASS ACRS THE REGION TUESDAY NIGHT.
THIS FEATURE WILL BRING A CHANCE OF SNOW SHOWERS AND HAVE RAISED
POPS UP INTO THE 40 PERCENT RANGE. ON WEDNESDAY...CAA WILL BE IN
FULL SWING AS LOW LEVEL MOIST...COLD CYCLONIC FLOW ACROSS THE
GREAT LAKES COMBINED WITH SOME DAYTIME HEATING WILL RESULT IN A
CHANCE OF SNOW SHOWERS...BEST FAVORED FROM LATE MORNING INTO THE
MID AFTERNOON HOURS. MODEL SOUNDINGS DEPICT STEEP LOW LEVEL LAPSE
RATES ALONG WITH THE LOW LEVEL MOISTURE INTERSECTING THE DENDRITIC
GROWTH ZONE. THE MAJORITY OF OPERATIONAL MODELS USED THIS FAR OUT
OUR NOT CONVECTIVE ALLOWING...AND AS A RESULT...MAY BE UNDER DOING
THE CONVECTIVE ACTIVITY AS HAS BEEN THE CASE THIS PAST WINTER.
HAVE RAISED POPS TO 40 PERCENT...BUT WOULD NOT BE SURPRISED IF THE
ACTIVITY ENDS UP BEING IN THE LIKELY CATEGORY.
COLD UPR LEVEL TROUGH WILL MOVE EAST WEDNESDAY NIGHT. THIS SHOULD
ALLOW SURFACE HIGH PRESSURE TO BUILD INTO THE REGION LATE. CLOUDS
WILL DECREASE AND WITH THE LOSS OF DAYTIME HEATING...SNOW SHOWERS
SHOULD WANE FROM WEST TO EAST.
AS FOR TEMPERATES...HIGHS ON TUESDAY WILL RANGE FROM THE UPPER
30S NORTH TO THE MID 40S SOUTH. HIGHS ON WEDNESDAY WILL STRUGGLE
TO WARM INTO THE MID AND UPPER 30S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
SURFACE HIGH PRESSURE WILL PUSH ACROSS THE AREA THURSDAY INTO
FRIDAY. THIS WILL PROVIDE FOR MAINLY DRY CONDITIONS ALONG WITH A
GRADUAL WARM UP EACH DAY. IN A NORTHWEST FLOW PATTERN
ALOFT...SHORT WAVE ENERGY WILL DROP DOWN INTO THE AREA FRIDAY INTO
SATURDAY. HOWEVER...THERE ARE SOME TIMING/STRENGTH AND PLACEMENT
ISSUES BETWEEN THE 12Z GFS/CMC AND 00Z ECMWF WITH THE GFS THE
FASTEST AND THE ECMWF THE SLOWEST. THE OVERALL TREND HAS BEEN
SLOWER SO WILL TRIM BACK POPS HEADING INTO FRIDAY AFTERNOON AND
THEN INCREASE THEM FOR FRIDAY NIGHT INTO SATURDAY. BOTH THE GFS
AND ECMWF LOOK LIKE THEY ARE TRYING TO LAY OUT A BOUNDARY
SOMEWHERE ACROSS THE OHIO OR TENNESSEE VALLEY LATE IN THE WEEKEND.
THIS WILL LIKELY LINGER PCPN ON INTO SUNDAY...ESPECIALLY ACROSS
OUR SOUTHERN AREAS. PTYPE THROUGH THE LATER PART OF THE LONG TERM
SHOULD GENERALLY BE RAIN...ALTHOUGH LOW LEVELS COULD COOL OFF
ENOUGH TO SEE THE POSSIBILITY OF SOME SNOW MIXING IN ACROSS THE
NORTH. TEMPERATURES WILL REMAIN NEAR TO SLIGHTLY BELOW NORMAL
THROUGH THE WEEKEND.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
A COLD FRONT IS SLOWLY APPROACHING THE REGION...AND A STEADY
STREAM OF RAIN WILL CONTINUE TO MOVE NORTHEAST THROUGH THE REGION
TODAY. WHILE CLOUDS OVER THE AREA ARE STILL GENERALLY IN THE
4000-6000 FOOT RANGE...SIGNIFICANTLY LOWER CLOUDS ARE LOCATED
UPSTREAM IN PARTS OF INDIANA AND KENTUCKY. TEMPO GROUPS HAVE BEEN
INCLUDED FOR ALL THE TAF SITES TO ATTEMPT TO TIME OUT THESE LOWER
CEILINGS...WHICH ARE EXPECTED TO BE IN THE 1000-1500 FOOT RANGE.
IFR CEILINGS ARE NOT OUT OF THE QUESTION...BUT IT LOOKS LIKE THIS
WILL BE MORE LIKELY NORTH AND WEST OF THE TAF SITES.
AS THE RAIN CONTINUES...OCCASIONAL MVFR VISIBILITIES ARE EXPECTED.
BY AFTERNOON...THE FRONTAL PASSAGE WILL PROMPT A QUICK CHANGE IN
WIND DIRECTION FROM THE SOUTH TO THE WEST-SOUTHWEST. WIND GUSTS
AHEAD OF...DURING...AND JUST AFTER THE FRONTAL PASSAGE MAY REACH
AS HIGH AS THE 25-30 KNOT RANGE. THE VAST MAJORITY OF THE
PRECIPITATION IS AHEAD OF THE FRONT...BUT SOME LIGHT SHOWERS ARE
EXPECTED BEHIND IT.
THOUGH THERE MAY BE SOME BRIEF CLEARING IN THE CLOUD DECKS
(ESPECIALLY JUST AFTER THE FRONT PASSES)...MVFR CEILINGS ARE
EXPECTED TO BE THE PREVAILING CONDITION. THESE CLOUDS SHOULD
PERSIST (AND EVEN LOWER A BIT) GOING INTO THE OVERNIGHT PERIOD AND
EARLY TUESDAY MORNING.
OUTLOOK...MVFR CEILINGS WILL BE POSSIBLE THROUGH TUESDAY MORNING.
MVFR CEILINGS ARE AGAIN EXPECTED ON TUESDAY NIGHT INTO WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...HICKMAN
LONG TERM...JGL
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
928 AM CDT MON MAR 11 2013
.SHORT TERM...
928 AM CDT MON MAR 11 2013
GIVEN CURRENT RADAR TREND WITH LINGERING STRETCHED DEFORMATION
BAND/STRONG 700-600MB FRONTOGENETIC FORCING...HAVE OPTED TO
EXTEND THE CURRENT WINTER STORM WARNING/WINTER WEATHER ADVISORY
TIL NOON TODAY. ALSO WITH TIGHTENING BAND OF SNOW...TRIMMED OFF
DODGE COUNTY IN MN FROM THE WINTER STORM WARNING AND MONROE COUNTY
IN WISCONSIN FROM THE WINTER WEATHER ADVISORY.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
346 AM CDT MON MAR 11 2013
A FAIRLY ACTIVE NORTHWEST FLOW REMAINS ACROSS THE AREA THROUGH
THIS TIME PERIOD. SHORT WAVES WILL BRING CHANCES OF PRECIPITATION
ON THURSDAY...FRIDAY AND FRIDAY NIGHT...AND SUNDAY AND SUNDAY
NIGHT. THE PRECIPITATION TYPES DURING THIS TIME FRAME IS HIGHLY
DEPENDENT ON WHERE THE BAROCLINIC ZONE SETS UP. THEREFORE JUST
WENT WITH A MIX OF RAIN AND SNOW FOR THESE TIME PERIODS.
&&
.AVIATION...TODAY AND TONIGHT
627 AM CDT MON MAR 11 2013
AN ELONGATED AREA OF LOW PRESSURE WAS LOCATED FROM NORTHERN
ILLINOIS INTO EASTERN WISCONSIN. DEFORMATION BAND OF SNOW WAS
LOCATED OVER NORTHEAST IOWA INTO SOUTHEAST MINNESOTA...AFFECTING
THE KRST TAF SITE WITH 1 1/2SM VISIBILITY IN SNOW. 11.08Z HRRR SHOWS
THIS BAND TO TRANSLATE EASTWARD THIS MORNING AS THE LOW PULLS
AWAY. THUS EXPECT VISIBILITIES TO DROP AT KLSE BETWEEN 14Z-17Z
INTO THE 1-3SM RANGE. EXPECT CEILINGS TO REMAIN IFR AT KRST UNTIL
17Z THEN RISE INTO THE MVFR CATEGORY. AT KLSE...CEILINGS WILL
REMAIN IN THE MVFR CATEGORY. THE SNOW WILL TAPER OFF EARLY THIS
AFTERNOON...BUT THE MVFR CEILINGS WILL CONTINUE THROUGH THE
REMAINDER OF THE TAF PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
928 AM CDT MON MAR 11 2013
WI...WINTER STORM WARNING UNTIL NOON CDT TODAY FOR WIZ017-029-032>034.
WINTER WEATHER ADVISORY UNTIL NOON CDT TODAY FOR WIZ041.
WINTER WEATHER ADVISORY UNTIL 10 AM CDT THIS MORNING FOR WIZ042.
MN...WINTER STORM WARNING UNTIL NOON CDT TODAY FOR MNZ079-087-088-094-
095.
WINTER WEATHER ADVISORY UNTIL NOON CDT TODAY FOR MNZ096.
WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR MNZ086.
IA...WINTER STORM WARNING UNTIL NOON CDT TODAY FOR IAZ008-009-018-019.
WINTER WEATHER ADVISORY UNTIL NOON CDT TODAY FOR IAZ010-029.
&&
$$
SHORT TERM...DAS
LONG TERM...BOYNE
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
627 AM CDT MON MAR 11 2013
.SHORT TERM...TODAY THROUGH WEDNESDAY
346 AM CDT MON MAR 11 2013
AT 3 AM...THE SURFACE LOW WAS OVER NORTHERN LAKE MICHIGAN. THE
850 MB LOW TRACKED 50 TO 100 MILES FURTHER NORTH THAN ORIGINALLY
ADVERTISED. THIS BROUGHT THE DRY SLOT INTO SOUTHWEST AND CENTRAL
WISCONSIN AND PARTS OF NORTHEAST IOWA...THUS CUTTING OFF MUCH OF
THE PRECIPITATION IN THESE AREAS. IT ALSO SHIFTED THE DEFORMATION
AREA FURTHER NORTH INTO SOUTHEAST MINNESOTA AND NORTH CENTRAL
WISCONSIN. THE 11.00Z MODELS ARE IN GOOD AGREEMENT THAT THE
DEFORMATION AXIS WILL BECOME ORIENTATED NORTH-SOUTH EARLY THIS
MORNING AND THEN MOVE SLOWLY EAST AND WEAKEN AS IT MOVES ACROSS
THE FORECAST AREA. ADDITIONAL SNOW AMOUNTS WILL BE LESS THAN
2 INCHES. WITH VERY LITTLE SNOW FALLING SOUTHEAST OF A MAUSTON
WISCONSIN TO OELWEIN IOWA LINE...DROPPED THE WINTER WEATHER
ADVISORIES AND WARNINGS IN THESE AREAS. ALSO...DOWNGRADED THE
WINTER STORM WARNING TO A WINTER WEATHER ADVISORY FOR FAYETTE AND
WINNESHIEK COUNTIES IN NORTHEAST IOWA...HOUSTON COUNTY IN
SOUTHEAST MINNESOTA...AND LA CROSSE AND MONROE COUNTIES IN
WEST-CENTRAL WISCONSIN.
FOR TONIGHT...ANOTHER WEAK WAVE WILL MOVE ACROSS EAST ACROSS THE
AREA. THIS SYSTEM WILL BRING SOME LIGHT SNOW TO THE AREA...BUT
THERE WILL BE LITTLE...IF ANY...ACCUMULATIONS FROM IT.
ON TUESDAY...A MUCH STRONGER SHORT WAVE TROUGH WILL MOVE EAST
THROUGH THE FORECAST AREA. DURING THE LATE MORNING AND AFTERNOON...
950-850 MB LAPSE RATES CLIMB TO AROUND 9C/KM AND CAPES WILL CLIMB
UP 100 J/KG. THIS WILL RESULT IN THE DEVELOPMENT OF SCATTERED
SHOWERS. SOUNDINGS SUGGEST TEMPERATURES WILL BE COLD ENOUGH ALOFT
FOR THE PRECIPITATION TO BE IN THE FORM OF SNOW.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
346 AM CDT MON MAR 11 2013
A FAIRLY ACTIVE NORTHWEST FLOW REMAINS ACROSS THE AREA THROUGH
THIS TIME PERIOD. SHORT WAVES WILL BRING CHANCES OF PRECIPITATION
ON THURSDAY...FRIDAY AND FRIDAY NIGHT...AND SUNDAY AND SUNDAY
NIGHT. THE PRECIPITATION TYPES DURING THIS TIME FRAME IS HIGHLY
DEPENDENT ON WHERE THE BAROCLINIC ZONE SETS UP. THEREFORE JUST
WENT WITH A MIX OF RAIN AND SNOW FOR THESE TIME PERIODS.
&&
.AVIATION...TODAY AND TONIGHT
627 AM CDT MON MAR 11 2013
AN ELONGATED AREA OF LOW PRESSURE WAS LOCATED FROM NORTHERN
ILLINOIS INTO EASTERN WISCONSIN. DEFORMATION BAND OF SNOW WAS
LOCATED OVER NORTHEAST IOWA INTO SOUTHEAST MINNESOTA...AFFECTING
THE KRST TAF SITE WITH 1 1/2SM VISIBILITY IN SNOW. 11.08Z HRRR SHOWS
THIS BAND TO TRANSLATE EASTWARD THIS MORNING AS THE LOW PULLS
AWAY. THUS EXPECT VISIBILITIES TO DROP AT KLSE BETWEEN 14Z-17Z
INTO THE 1-3SM RANGE. EXPECT CEILINGS TO REMAIN IFR AT KRST UNTIL
17Z THEN RISE INTO THE MVFR CATEGORY. AT KLSE...CEILINGS WILL
REMAIN IN THE MVFR CATEGORY. THE SNOW WILL TAPER OFF EARLY THIS
AFTERNOON...BUT THE MVFR CEILINGS WILL CONTINUE THROUGH THE
REMAINDER OF THE TAF PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
346 AM CDT MON MAR 11 2013
WI...WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR WIZ017-029-
032>034.
WINTER WEATHER ADVISORY UNTIL 10 AM CDT THIS MORNING FOR WIZ041-
042.
MN...WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR MNZ079-
086>088-094-095.
WINTER WEATHER ADVISORY UNTIL 10 AM CDT THIS MORNING FOR MNZ096.
IA...WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR IAZ008-009-
018-019.
WINTER WEATHER ADVISORY UNTIL 10 AM CDT THIS MORNING FOR IAZ010-
029.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1049 AM MDT MON MAR 11 2013
.UPDATE...
&&
.SHORT TERM...NORTHWEST FLOW ALOFT ACROSS REGION AT THIS TIME.
MOISTURE HAS INCREASED ACROSS MOUNTAINS AS OROGRAPHICS IMPROVE.
WEB CAMS SHOWING LIGHT SNOW OCCURRING ALONG CONTINENTAL DIVIDE OF
SUMMIT GRAND AND BOULDER COUNTIES AS WELL AS THE HIGHER PEAKS IN
ROCKY MOUNTAIN PARK. AIRMASS STILL FAIRLY STABLE WITH LAPSE RATES
AROUND 5 C/KM. LATEST SATELLITE SHOWING JET STREAK MOVING ACROSS
WYOMING AT THIS TIME. MOISTURE TO CONTINUE TO SPREAD INTO
MOUNTAINS THIS AFTERNOON AND EVENING WITH CONTINUED OROGRAPHICS.
LATEST RAP INDICATING LAPSE RATES IMPROVE TO AROUND 7 C/KM AS
POCKET OF MID LEVEL COOLING MOVES OVER THE AREA. WILL MAKE SOME
UPWARD ADJUSTMENTS TO POPS ACROSS MOUNTAINS THIS AFTERNOON BASED
ON CURRENT TRENDS. WILL ALSO INCREASE SNOW AMOUNTS A BIT ALONG THE
DIVIDE AND ACROSS ZONE 31 THIS AFTERNOON. ZONE 31 ON DOWNSLOPE
SIDE OF THIS NORTHWEST FLOW SO AMOUNTS WILL STILL BE LIMITED.
ACROSS PLAINS...SHOULD SEE SOME INCREASE IN MID AND HIGH LEVEL
CLOUDS AS JET APPROACHES. SHOULD SEE SOME SHOWERS DEVELOP TOWARDS
EVENING ACROSS NORTHEAST CORNER AWAY FROM DOWNSLOPE FLOW. LATEST
RAP AND HRRR SUGGESTING SOME LIGHT PRECIP IN AN AREA EAST OF A
GREELEY TO LIMON LINE AFTER 21Z...CONTINUING THROUGH THE EVENING.
WILL MAKE SOME ADJUSTMENTS LATE THIS AFTERNOON FOR THIS TREND.
SOME CONCERN FOR ANTICYCLONIC UPSLOPE DEVELOPING AS FAR WEST AS
THE DENVER AREA THIS EVENING...WHICH COULD INCREASE SNOW CHANCES
FOR DENVER. FOR NOW WILL CONTINUE WITH THE SLIGHT CHANCE FOR
DENVER. MODELS HAVE BEEN CONSISTENT WITH SOME LIGHT QPF AND SNOW
AMOUNTS THIS EVENING IN AN AREA OVER NORTHEAST WELD...MORGAN AND
WASHINGTON COUNTIES INTO THE NORTHEAST CORNER. MAY NEED TO
INCREASE POPS THERE FOR THE EVENING...FOR NOW WILL CONTINUE WITH
THE CHANCE POPS.
.AVIATION...WINDS SHIFTING TO THE NORTHWEST AS SYSTEM MOVES ACROSS
WYOMING. NORTHWEST DIRECTION TO PREVAIL THROUGH THE AFTERNOON AS
SOME MIXING STILL EXPECTED. STILL A SLIGHT CHANCE OF WINDS TURNING
NORTHEAST TOWARDS EVENING...WITH LOWERING CEILINGS AND POSSIBLE
ILS CONDITIONS. WILL CONTINUE TAF TRENDS AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 442 AM MDT MON MAR 11 2013/
SHORT TERM...A JET STREAK WILL DROP ACROSS NORTHEAST COLORADO
TONIGHT. CURRENT MOUNTAIN WAVE WILL DIMINISH AS THE STABILITY
STRUCTURE GOES AWAY. THERE IS A BRIEF DECREASE IN HIGH
CLOUDS...THEN THEY SHOULD COME BACK THIS AFTERNOON. AREA OF LIFT
WILL SLIDE ACROSS THE NORTHEAST CORNER OF THE STATE OVERNIGHT. NOT
THAT IMPRESSED WITH WHAT IS HAPPENING UPSTREAM...AS AREAS UNDER
THE LIFT NOW HAVE FAIRLY HIGH CEILINGS AND NOT MUCH PRECIPITATION.
BUT THERE WILL BE SOME INSTABILITY UNDER THIS AREA AND THE LIFT IS
REAL. MODELS ALL SHOW A BAND WITH SEVERAL INCHES OF SNOW THROUGH
STERLING AND AKRON OVERNIGHT. AMOUNTS SEEM A BIT MUCH GIVEN THE
MOISTURE AVAILABLE...BUT I WILL RAISE POPS IN THIS AREA. WITH A
WESTERLY COMPONENT OFF THE GROUND...I WILL KEEP THE POPS AWAY FROM
THE FRONT RANGE...WE WILL PROBABLY DEVELOP AN ANTICYCLONE WITH THE
SHOWERS ON THE NORTHEAST SIDE OF THE LOW LEVEL SHEAR ZONE...SO
PROBABLY NOT MUCH CHANCE FROM FORT COLLINS-DIA AND WESTWARD. FOR
THE MOUNTAINS INCREASING MOISTURE AT OR BELOW MOUNTAINTOP LEVEL
THIS AFTERNOON...WE SHOULD SEE SOME OROGRAPHIC SNOW THOUGH IT WILL
NOT BE AS UNSTABLE AS WILL BE OVER THE PLAINS. NAM SNOWFALL OF UP
TO 4 INCHES IS PROBABLY A BIT MUCH...BUT HERE TOO I WILL RAISE
POPS FOR LIGHT SNOW. DROPPED LOW TEMPERATURES A BIT TONIGHT IN
LINE WITH THE LATEST GUIDANCE.
LONG TERM...FAIRLY STRONG NORTHWESTERLY FLOW ALOFT IS PROGGED
FOR THE CWA TUESDAY THROUGH WEDNESDAY...DECREASING IN SPEED A BIT
BY WEDNESDAY NIGHT BUT STILL TO STAY NORTHWESTERLY. MODELS KEEP AN
UPPER RIDGE OVER THE WESTERN U.S. THROUGH THE PERIOD. THE SYNOPTIC
SCALE ENERGY IS VERY WEAK AND DOWNWARD IN NATURE TUESDAY THROUGH
WEDNESDAY NIGHT. THE BOUNDARY LAYER FLOW WILL MAINLY ADHERE TO
NORMAL DIURNAL PATTERNS THROUGH THE PERIOD. CONCERNING
MOISTURE...THERE IS SOME PROGGED IN THE LOWER LEVELS ON TUESDAY.
BY TUESDAY NIGHT...MOISTURE DECREASES OVER THE EASTERN HALF OF THE
CWA...WITH SOME LINGERING OVER THE MOUNTAINS. WEDNESDAY AND
WEDNESDAY NIGHT ARE PRETTY DRY. THE QPF FIELDS HAVE A TAD OF
MEASURABLE SNOW OVER THE HIGH MOUNTAINS TUESDAY MORNING...THEN
THERE IS NOTHING ANYWHERE THROUGH WEDNESDAY NIGHT. WILL KEEP MINOR
POPS GOING IN THE HIGH MOUNTAINS TUESDAY INTO TUESDAY
EVENING...THATS IT. FOR TEMPERATURES...TUESDAY`S HIGHS DO NOT LOOK
AS WARM AS THEY DID FROM YESTERDAY`S 00Z MODEL RUNS. THEY ARE NOW
0-2 C COOLER THAN TODAY`S EXPECTED READINGS. WEDNESDAY`S HIGHS ARE
3-8 C WARMER THAN TUESDAY`S HIGHS. FOR THE LATER DAYS...THURSDAY
THROUGH SUNDAY...THE UPPER RIDGE IS PROGGED TO SLOWLY MAKE ITS WAY
EAST GETTING OVER COLORADO ON FRIDAY. THE ECMWF STILL SHOWS A WEAK
UPPER TROUGH TO MOVE INTO THE CWA...BUT NOW IT MOVE ACROSS LATE
SATURDAY INTO SATURDAY NIGHT AND IT IS WEAKER THAN YESTERDAY`S RUN
INDICATED. WILL INCREASE CLOUDINESS A BIT SATURDAY AND SUNDAY...
BUT NO POPS FOR THE LAST FOUR DAYS ANYWHERE. TEMPERATURES LOOK TO
BE ABOVE SEASONAL NORMALS ALL FOUR DAYS.
AVIATION...VFR CONDITIONS TODAY. NORTH TO NORTHWEST WINDS SHOULD
MIX DOWN BY EARLY AFTERNOON...TURNING NE OR POSSIBLY SE BY EARLY
EVENING. CEILINGS MAY LOWER ENOUGH TO REQUIRE INSTRUMENT
APPROACHES TO KDEN OVERNIGHT...THOUGH THERE IS ONLY A SLIGHT
CHANCE OF SNOW SHOWERS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
649 PM EDT MON MAR 11 2013
...SHALLOW COASTAL FLOODING AROUND HIGH TIDE THIS EVENING ALONG
THE LOWER SOUTH CAROLINA COAST...
.SYNOPSIS...
HIGH PRESSURE WILL SHIFT OFFSHORE THROUGH THE EVENING. A COLD FRONT
WILL ADVANCE INTO CENTRAL GEORGIA AND THE CAROLINAS TONIGHT. THE
FRONT WILL MOVE OFF THE COAST TUESDAY MORNING FOLLOWED BY HIGH
PRESSURE THROUGH SATURDAY. A WEAK BACKDOOR COLD FRONT MAY APPROACH
FROM THE NORTH ON SUNDAY AND POSSIBLY LINGER IN THE AREA INTO EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
UPPER LEVEL LOW PRESSURE SPINNING OVER SOUTHERN MICHIGAN WILL
WEAKEN TONIGHT AS IT MOVES NORTH INTO SOUTHERN QUEBEC AND
SOUTHEAST ONTARIO. THE ATTENDANT COLD FRONT STRETCHES FROM SURFACE
LOW PRESSURE NEAR SOUTHERN LAKE MICHIGAN SOUTH THROUGH THE OHIO
AND TENNESSEE VALLEYS AND INTO THE CENTRAL GULF OF MEXICO. THE
FRONT WILL STEADILY MARCH EAST AND POSITIONED BE VERY NEAR THE
COAST BY SUNRISE TUESDAY. GOES-EAST WATER VAPOR IMAGERY SHOWS A
LARGE PLUME OF TROPICAL MOISTURE SURGING NORTH ACROSS MUCH OF THE
EASTERN U.S. WITH BLENDED AMSU/SSMI DATA PINGING PWATS IN EXCESS
OF 1.50 INCHES ACROSS SOUTHERN ALABAMA AND GEORGIA. THESE VALUES
WILL ADVECT EAST INTO SOUTHERN SOUTH CAROLINA AND SOUTHEAST
GEORGIA BY MIDNIGHT AS PRE-FRONTAL LOW-LEVEL JETTING STRENGTHENS.
RAIN CHANCES WILL STEADILY INCREASE FROM WEST-EAST OVERNIGHT AS
THE COLD FRONT DRAWS CLOSER AND SHORTWAVE ENERGY CURRENTLY MOVING
ACROSS THE SOUTHERN MISSISSIPPI VALLEY EJECTS NORTHEAST ACROSS
NORTHERN GEORGIA AND THE SOUTHERN APPALACHIANS. WILL INCREASE POPS
TO 100 PERCENT FOR ALL AREAS TONIGHT WITH THE BULK OF THE HEAVIEST
RAINS LIKELY FALLING BETWEEN MIDNIGHT AND SUNRISE...POSSIBLY A BIT
EARLIER ACROSS FAR INTERIOR SOUTHEAST GEORGIA. GENERALLY USED A
BLEND OF THE HIGHER RESOLUTION H3R AND RAP RUNS TO CONSTRUCT
HOURLY WEATHER PARAMETERS THROUGH 6 AM. AVERAGE RAIN AMOUNTS OF
0.25-0.75 INCH LOOKS REASONABLE WITH LOCALLY HIGHER VALUES LIKELY.
HOURLY TEMPERATURES WILL BE A BIT ATYPICAL WITH THE AREA HOLDING
WELL INTO THE WARM SECTOR UNTIL EARLY TUESDAY MORNING. LOWS WILL
RANGE FROM THE MID 50S ACROSS FAR INTERIOR SOUTHEAST GEORGIA TO
THE LOWER 60S AT THE COAST.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
TUESDAY...THERE ARE SOME SLIGHT TIMING DIFFERENCES REGARDING THE
COLD FRONTAL PASSAGE IN THE LATEST 12Z NUMERICAL MODEL
SOLUTIONS...YET EVEN THE SLOWEST SCENARIOS HAVE THE FRONT
OFFSHORE BY MID TO LATE MORNING. WILL THUS CONTINUE TO ADVERTISE
70 TO 80 PERCENT RAIN CHANCES GENERALLY ALONG AND EAST OF
INTERSTATE 95 AT DAYBREAK...WITH POPS 50 PERCENT AND LOWER JUST TO
THE WEST. PRECIPITATION POTENTIAL WILL RAPIDLY DIMINISH BEHIND
THE FRONT AS THE MORNING PROGRESSES...AND HAVE INDICATED ONLY
SLIGHT CHANCES REMAINING FOR THE CHARLESTON TRI COUNTY AREA BY MID
AFTERNOON. TEMPERATURES WILL ONLY BE A FEW DEGREES COOLER THAN
MONDAY...PEAKING FROM 70 TO 72 DEGREES...A COMBINED RESULT OF
DELAYED COLD ADVECTION BEHIND THE FRONT AND THE WARMING EFFECTS OF
INCREASING SUNSHINE AND DOWNSLOPE FLOW. MINIMUM TEMPERATURES
TUESDAY NIGHT WILL REFLECT THE COOLING TREND...FALLING MORE THAN
10 DEGREES LOWER THAN THE PREVIOUS NIGHT...INTO THE 40 DEGREE
RANGE.
WEDNESDAY AND THURSDAY...THE AXIS OF A SHORTWAVE TROUGH WILL SWING
ACROSS THE EAST COAST WEDNESDAY AFTERNOON...AS CENTRAL CANADIAN
HIGH PRESSURE BUILDS INTO THE REGION THROUGH THE LATE WEEK PERIOD.
STRONG COLD ADVECTION WILL INITIATE ACCORDINGLY...AND WHEN COMBINED
WITH LOWERING HEIGHTS ALOFT...WILL SUPPRESS HIGH TEMPERATURES IN
THE MID TO UPPER 60S WEDNESDAY AFTERNOON. BREEZY CONDITIONS ARE
ALSO EXPECTED DURING THE DAYTIME HOURS ON WEDNESDAY...AS DECENT
DIURNAL MIXING TAPS INTO 30 KT BOUNDARY LAYER WINDS. HIGH
TEMPERATURES WILL ACTUALLY BE A DEGREE OR TWO LOWER ON
THURSDAY...WITH WINDS VEERING TOWARD THE NORTH AND DOWNSLOPE
WARMING EFFECTS DIMINISHING. ABUNDANT SUNSHINE AND DRY CONDITIONS
WILL PREVAIL.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A BROAD UPPER RIDGE WILL SPREAD EAST THURSDAY NIGHT THROUGH
SATURDAY...SUPPORTING A WARMING TREND AND DRY WEATHER.
TEMPERATURES WILL BE BACK INTO THE 70S BY SATURDAY GIVEN CURRENT
TRENDS. UNCERTAINTY INCREASES SUNDAY INTO MONDAY CONSIDERING SOME
DISCREPANCIES IN MEDIUM RANGE MODEL SOLUTIONS. THE LATEST ECMWF IS
STILL SHOWING A PRONOUNCED UPPER TROUGH DIGGING INTO THE CENTRAL
UNITED STATES ON MONDAY...WITH THE 12Z GFS COMING MORE INTO LINE
WITH THIS SCENARIO. HAVE MAINTAINED A DRY EXTENDED FORECAST WITH
ABOVE NORMAL TEMPERATURES...WHILE SHOWING AN INCREASE IN CLOUD
COVER TO ACCOUNT FOR A MORE UNSETTLED PATTERN TOWARD THE END OF
THE PERIOD.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
TO BE ISSUED SHORTLY.
EXTENDED AVIATION OUTLOOK...THERE ARE NO CONCERNS WITH A GREATER
THAN 30 PERCENT CONFIDENCE AT THIS TIME.
&&
.MARINE...
TONIGHT...LATEST SWAN AND WW4 OUTPUT SUGGEST 6 FT SEAS WILL AFFECT
THE GEORGIA NEARSHORE WATERS LATER TONIGHT THROUGH TUESDAY
MORNING. EXPANDED THE SMALL CRAFT ADVISORY INTO THIS AREA GIVEN
THIS LATEST MODEL TREND.
WINDS/SEAS WILL THEN INCREASE/BUILD OVER ALL WATERS TONIGHT AS
LOW LVL WINDS ENHANCE OVER THE WATERS AND THE COLD FRONT
APPROACHES THE COAST LATE. SOUTHERLY FLOW INCREASING TO 15-20 WITH
GUSTS TO 25 KT IS FORECAST TO BUILD SEAS TO 4-6 FT WITHIN 20 NM
AND 5-8 FT 20-60 NM OFFSHORE. A SMALL CRAFT ADVISORY WILL
THEREFORE REMAIN IN EFFECT FOR MARINE LEGS WITH THE EXCEPTION OF
THE CHARLESTON HARBOR.
WINDS AND SEAS FOR THE NEARSHORE WATERS WILL DIMINISH BELOW
ADVISORY CRITERIA NO LATER THAN TUESDAY AFTERNOON AS THE COLD
FRONT PUSHES OFFSHORE...WHILE SEAS MAINTAIN ADVISORY CONDITIONS
ACROSS THE OUTER GEORGIA WATERS. COLD ADVECTION WILL BE SLIGHTLY
DELAYED BEHIND THE FRONT...WITH THE MAIN SURGE EXPECTED MORE
TOWARD WEDNESDAY. THE DEEPEST MIXING WILL BE ACROSS THE WARMER
OFFSHORE WATERS...MAINLY BEYOND 20 NM FROM THE COAST. THUS THE
OUTER GEORGIA MARINE ZONES WILL REMAIN UNDER A SMALL CRAFT
ADVISORY THROUGH THURSDAY. FREQUENT GUSTS UP TO 25 KT ACROSS
PORTIONS OF THE NEARSHORE WATERS COULD NECESSITATE ADVISORIES FOR
THOSE AREAS AS WELL. MUCH WEAKER FLOW EXPECTED THURSDAY INTO THE
WEEKEND AS HIGH PRESSURE BUILDS FROM THE WEST/NORTHWEST.
&&
.TIDES/COASTAL FLOODING...
TIDES ANOMALIES ARE RUNNING 1 FT ABOVE PREDICTED IN THE CHARLESTON
HARBOR EARLY THIS EVENING. CURRENT TRENDS SUGGEST TIDE LEVELS WILL
PEAK VERY NEAR 7.0 FT MLLW WITH HIGH TIDE THIS EVENING. THE
SITUATION LOOKS MARGINAL...BUT GIVEN THE AMOUNT OF TIDAL LOADING
THAT HAS OCCURRED OVER THE PAST SEVERAL HIGH TIDES...WILL HOIST A
COASTAL FLOOD ADVISORY FOR THE SOUTH CAROLINA COASTAL
ZONES...EXCLUDING TIDAL BERKELEY...FROM 8 PM UNTIL 11 PM.
HIGH TIDE WILL OCCUR IN THE CHARLESTON HARBOR AT 844 PM AND IN THE
BEAUFORT RIVER AT BEAUFORT AT 959 PM.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...COASTAL FLOOD ADVISORY UNTIL 11 PM EDT THIS EVENING FOR
SCZ048>051.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EDT TUESDAY FOR AMZ350-352.
SMALL CRAFT ADVISORY UNTIL 11 AM EDT TUESDAY FOR AMZ354.
SMALL CRAFT ADVISORY UNTIL 2 PM EDT THURSDAY FOR AMZ374.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
141 PM EDT MON MAR 11 2013
.AVIATION...
VARIABLE CIGS IMPACTED KSBN FOR A SHORT PERIOD OF TIME IN THE WAKE
OF THE FRONTAL BOUNDARY SWEEPING ACROSS THIS MORNING. LOW CLOUDS
ASSOCIATED WITH THE UPPER LOW ITSELF WERE DRIFTING BACK IN FROM
ILLINOIS AND WILL CAUSE A RETURN TO LOW END MVFR CONDITIONS WITH
SOME EXCURSIONS TO IFR POSSIBLE TONIGHT. AT KFWA TAFS HAVE BEEN
ADJUSTED TO REFLECT THE TEMP IMPROVEMENT IN FLGT CONDITIONS BEFORE
RETURNING LATER THIS AFTERNOON. NO FURTHER DETAIL ADDED BEYOND
00-02Z WITH PERSISTENT CAA AND LOW CLOUDS WITH UPPER LOW LINGERING
ACROSS THE AREA THROUGH THE REMAINDER OF THE PERIOD.
&&
.UPDATE...
SECOND UPDATE OF THE DAY ISSUED TO ADJUST FOR RADAR TRENDS AS
RETURNS CONTINUE TO INCREASE AHEAD OF AND JUST BEHIND FAST MOVING
FRONT. HRRR FOR PAST FEW HOURS HAS HINTED AT A BIT OF A FINE LINE
OF COVECTION POSSIBLY DEVELOPING AND RECENT TREDNS SUGGEST THIS
MAY BE UNDERWAY NEAR THE IN/OH STATE LINE AS SFC DWPTS APPROACH 50
DEGREES. ONE STRAY LIGHTNING STRIKE WAS DETECTED NOT TO LONG AGO
EAST OF AUBURN INDIANA. WHILE THERE MAY ONLY BE ONE OR 2 MORE
STRIKES PRIOR TO DEPARTURE FROM THE AREA OPTED TO ADD SLGT CHC
MENTION TO ZONES/GRIDS FOR A FEW HOURS. OTHERWISE PRECIP WILL COME
TO AND END FROM SW TO NE THROUGH THE AFTERNOON WITH GENERALLY DRY
CONDTIONS ALREADY SEEN ALONG AND WEST OF US 31. TEMPS WILL FALL
OFF AS THE RAIN CLEARS WITH READINGS DROPPING INTO THE 30S.
HOWEVER...ANY MIX OR SWITCH TO SNOW STILL LOOKS TO OCCUR CLOSER
TO/AFTER 00Z. WILL ADDRESS IN REGULAR FORECAST PACKAGE.
&&
.PREV DISCUSSION... /ISSUED 433 AM EDT MON MAR 11 2013/
SHORT TERM...
DEEP LYRD CYCLONE OVR CNTRL IA WILL LIFT OUT THROUGH NRN LWR MI
TONIGHT AS SFC FNTL ZONE SHIFTS EWD ACRS CWA TDA. RAINFALL IN
ASSOCN/W THIS SYS HAS LARGELY BEEN A BUST SO FAR TIED TO POOR EWD
MOISTENING AS PLAINLY ILLUSTRATED IN 00Z RAOBS FM ILN/DTX. HWVR
W/SFC BNDRY STILL PLANTED THROUGH CNTRL IL AND CONTD WARM SECTOR LL
MSTR FLUX -SHRA WOULD STILL APPEAR TO BE A GOOD PROSPECT THROUGH
EARLY AFTN TIED TO NEARING SFC FNTL ZONE AND ASSOCD LL SATURATED
ASCENT. OTRWS WELL DVLPD WRAP AROUND DEFORMATION ZONE ACRS WRN IA
LOOKS TO CARRY EWD AND GRAZE MUCH OF THE AREA LT THIS AFTN/EARLY
THIS EVENING W/A PD OF LT SNOW SHOWERS...TIMED W/INTENSIFYING LL
THERMAL TROUGHING. HWVR MARGINAL VERTICAL ASCENT/SFC TEMPS SHLD
YIELD LTL TO NO SNOW ACCUMULATION THIS EVENING.
SECONDARY FOLLOWING UPR DISTURBANCE DROPPING WWD THROUGH BASE OF
LARGER SCALE TROUGH POSITIONED THROUGH THE WRN LAKES ON TUE SHLD
YIELD ENHANCED DIURNAL SHSN TUE AFTN/EVE AND WILL BACK/EXPAND PRIOR
POPS QUITE A BIT IN CONCERT W/EVEN STRONGER/DEEPER LL THERMAL
TROUGHING AND UNDER GUISE OF STEEP LL LAPSE RATES DVLPG IN MOIST
CYCLONIC FLW.
DIFFICULT NR TERM TEMP FCST GIVEN WWD POSITION OF SFC CDFNT THIS
MORNING. WILL GENERALLY FOLLOW CLOSE KNIT MOS BLEND WHICH YIELDS A
PREFERRED NON-DIURNAL CURVE WRN HALF AND FLAT LINES ERN HALF. MUCH
COLDER AIR TO FILTER IN OVERNIGHT AND AGAIN LT TUE.
LONG TERM...
WEDNESDAY THROUGH SUNDAY...VERY COLD AIR WILL BE OVER THE FORECAST
AREA WEDNESDAY WITH THE LIKELIHOOD OF A WEAK SHORT WAVE TROF MOVING
ACROSS THE WESTERN GREAT LAKES REGION. HAVE ADDED A CHANCE FOR SNOW
SHOWERS MOST AREAS WEDNESDAY GIVEN SHALLOW BUT STEEP LAPSE RATES
EXPECTED WITH RESIDUAL MOISTURE FROM RECENT SNOWMELT AND LIGHT
PRECIPITATION IN CONJUNCTION WITH DAYTIME HEATING. EXPECT ALSO SOME
LAKE ENHANCEMENT UPSTREAM WITH FAVORABLE PRECONDITIONING OF THE LOW
LEVELS. AFTER WEDNESDAY...A ECMWF/GFS CONSENSUS FAVORS THE FLOW
BECOMING HIGH ZONAL LATE IN THE WEEK WITH MODERATING TEMPERATURES...
SO CONTINUED TO TREND HIGHS WARMER FRIDAY. HOWEVER...CONFIDENCE
BECOMES VERY POOR BY SUNDAY AS REFLECTED IN THE GFS MEX MODEL OUTPUT
WITH VERY HIGH STANDARD DEVIATIONS...THUS...TRIED TO KEEP
PERSISTENCE FOR THE 2ND HALF OF THIS PERIOD.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 PM EDT
WEDNESDAY FOR LMZ043-046.
&&
$$
SHORT TERM...T
LONG TERM...SKIPPER
AVIATION...FISHER
UPDATE...FISHER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
313 PM MDT MON MAR 11 2013
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 1215 PM MDT MON MAR 11 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS INDICATE NW FLOW IN PLACE
ACROSS PLAINS WITH TROUGH OVER GREAT LAKES AND RIDGE BUILDING ALONG
WEST COAST. SEVERAL WEAK SHORTWAVES WITHIN THE MEAN FLOW HAVE LEAD
TO DEVELOPMENT OF HIGH CLOUDS ACROSS THE REGION.
PRIMARY FORECAST CONCERN FOR SHORT TERM WILL BE POTENTIAL FOR LIGHT
SNOW LATE TONIGHT ACROSS THE CWA. A FAST MOVING SHORTWAVE TROUGH
OVER THE NORTHERN PLAINS WILL SHIFT SOUTH THIS EVENING AND OVER THE
CWA TONIGHT. LARGE SCALE FORCING IS ADVERTISED ACROSS THE CENTRAL
PART OF THE CWA...WITH MOISTURE PROFILES SATURATING LATER THIS
EVENING. THERE IS GOOD MODEL OVERLAP IN TIMING OF QPF FROM WEST TO
EAST THROUGH THE EVENING AND OVERNIGHT...WITH PRECIP STARTING AS
RAIN LATE THIS AFTERNOON OVER EASTERN COLORADO AND TRANSITIONING TO
ALL SNOW THIS EVENING. WITH INCREASING CONFIDENCE IN MEASURABLE
PRECIP I INCREASED POPS TO LIKELY CATEGORY ACROSS THE CENTRAL PART
OF THE CWA IN LINE WITH MODEL CONSENSUS. THERE IS STILL WEAK
INSTABILITY ADVERTISED WITH SNOW BAND...AND WITH STRONG FRONTOGENESIS
IMMEDIATELY BEHIND SHORTWAVE WE COULD SEE NARROW BANDING. QPF AMOUNTS
ARE GENERALLY LIGHT...AND WITH MARGINAL MOISTURE ADVECTION AND THE
FAST NATURE OF THIS SYSTEM I AM ONLY ANTICIPATING AROUND ONE INCH OF
SNOWFALL AT THE MOST. ANY LINGERING SNOW SHOULD QUICKLY COME TO AN
END AROUND SUNRISE TUESDAY MORNING.
DRY CONDITIONS ARE THEN EXPECTED THROUGH THE REST OF THE DAY TUESDAY
WITH ONLY HIGH CLOUDS POSSIBLY LINGERING THROUGH THE DAY. AIR MASS
SHOULD BE COOLER THAN TODAY...THOUGH IMPACTS FROM SNOW PACK SHOULD
BE MINIMAL. WE COULD SEE IMPACT FROM SKY COVER...BUT FOR NOW I KEPT
FORECAST SIMILAR TO TODAY...WITH MID/UPPER 40S IN THE NORTHEAST TO
LOW 50S IN THE SOUTHWEST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 255 PM MDT MON MAR 11 2013
FORECAST CONCERN IN THE LONG TERM PERIOD IS THE POSSIBILITY OF
PRECIPITATION THIS WEEKEND.
THE AXIS OF THE BROAD UPPER RIDGE TRANSLATES FROM THE WEST COAST
TO THE INTERMOUNTAIN AND ROCKY MOUNTAIN REGION BETWEEN TUESDAY
NIGHT AND THURSDAY NIGHT. BY FRIDAY THE RIDGE BEGINS TO FLATTEN AS
SEVERAL SHORT WAVE TROUGH BEGIN TO RIDE UP OVER THE APEX OF THE
RIDGE. THESE WAVES ARE EXPECTED TO REMAIN NORTH OF THE CENTRAL
HIGH PLAINS REGION THROUGH AT LEAST SATURDAY MORNING.
THEREFORE...THE FORECAST AREA IS EXPECTED TO REMAIN DRY AND WARM
THROUGH SATURDAY NIGHT WITH A PERSISTENT LEE TROUGH REMAINING IN
PLACE IN THE VICINITY OF THE EASTERN COLORADO BORDER AREA.
EARLY SATURDAY...IT APPEARS THAT A COOLER AREA OF HIGH PRESSURE
WILL MOVE SOUTHWARD ACROSS THE PLAINS STATES WITH A BACKDOOR COLD
FRONT PUSHING INITIALLY INTO THE EASTERN PORTION OF THE FORECAST
AREA WITH COOLER AIR REMAINING GENERALLY IN PLACE ACROSS THE
PLAINS THROUGH THE END OF THE WEEKEND AND INTO THE BEGINNING OF
NEXT WEEK. THE GFS AND ECMWF ARE NO LONGER COMPLETELY OUT OF PHASE
WITH EACH OTHER AT THIS POINT...BUT CONTINUE TO OFFER SOMEWHAT
DIFFERENT SOLUTIONS WITH THE NEXT UPPER TROUGH ENTERING THE
PACIFIC NORTHWEST AND TRACKING EAST OF THE ROCKIES SOMETIME IN THE
SUNDAY TO SUNDAY NIGHT TIME FRAME. WITH SEVERAL SMALLER SHORT WAVE
TROUGHS PRECEDING THE MAIN UPPER TROUGH AND WITH THE APPROACH AND
PASSAGE OF THE MAIN UPPER TROUGH...EXPECT AT LEAST A SLIGHT CHANCE
OF PRECIPITATION OVER THE FORECAST AREA FROM LATE SATURDAY THROUGH
AT LEAST SUNDAY NIGHT AND POSSIBLY THE DAY ON MONDAY...DEPENDING
UPON THE MODEL SOLUTION THAT ENDS UP CLOSER TO REALITY. HAVE
THEREFORE GONE WITH A FAIRLY BROAD BRUSHED SOLUTION THROUGH THE
WEEKEND AND INTO MONDAY WITH A SLIGHT CHANCE OF LIGHT RAIN WITH
LIGHT ACCUMULATIONS DURING THAT TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1134 AM MDT MON MAR 11 2013
VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THIS EVENING AT BOTH
TERMINALS. MVFR CONDITIONS WILL DEVELOP OVER KGLD AT A BAND OF
RAIN/SNOW DEVELOPS LATE THIS AFTERNOON AND EVENING OVER EASTERN
COLORADO AND SPREADS INTO NORTHWEST KANSAS AS ALL SNOW TONIGHT. I
COULDNT RULE OUT BRIEF IFR CONDITIONS ALONG MOST INTENSE PART OF
SNOW BAND TONIGHT...HOWEVER I WAS NOT CONFIDENT ENOUGH TO PREVAIL
OR INCLUDE TEMPO GROUP...SINCE LOCATION OF THIS BAND IS STILL IN
QUESTION. CHANCE ARE LOWER FOR PRECIP/MVFR AT AT THE KMCK
TERMINAL SO CURRENTLY HAVE VFR CONTINUING WITH VCSH. VFR
CONDITIONS SHOULD PREVAIL AT BOTH TERMINALS AFTER 12Z WHEN PRECIP
QUICKLY MOVES EAST.
WINDS HAVE BEEN SLOWER TO INCREASE AT BOTH TERMINALS TODAY WITH
THICK HIGH CLOUDS OVERHEAD.I STILL EXPECT WIND GUSTS AROUND 20KT
BY MID AFTERNOON...DECREASING AROUND SUNSET. GUSTY WEST WINDS
SHOULD REDEVELOP AROUND 15Z TUESDAY WITH CLEARING SKIES AND BETTER
DAYTIME MIXING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...LOCKHART
AVIATION...DR
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1215 PM MDT MON MAR 11 2013
.SHORT TERM...(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 1215 PM MDT MON MAR 11 2013
LATEST WV IMAGERY AND RUC H5 ANALYSIS INDICATE NW FLOW IN PLACE
ACROSS PLAINS WITH TROUGH OVER GREAT LAKES AND RIDGE BUILDING ALONG
WEST COAST. SEVERAL WEAK SHORTWAVES WITHIN THE MEAN FLOW HAVE LEAD
TO DEVELOPMENT OF HIGH CLOUDS ACROSS THE REGION.
PRIMARY FORECAST CONCERN FOR SHORT TERM WILL BE POTENTIAL FOR LIGHT
SNOW LATE TONIGHT ACROSS THE CWA. A FAST MOVING SHORTWAVE TROUGH
OVER THE NORTHERN PLAINS WILL SHIFT SOUTH THIS EVENING AND OVER THE
CWA TONIGHT. LARGE SCALE FORCING IS ADVERTISED ACROSS THE CENTRAL
PART OF THE CWA...WITH MOISTURE PROFILES SATURATING LATER THIS
EVENING. THERE IS GOOD MODEL OVERLAP IN TIMING OF QPF FROM WEST TO
EAST THROUGH THE EVENING AND OVERNIGHT...WITH PRECIP STARTING AS
RAIN LATE THIS AFTERNOON OVER EASTERN COLORADO AND TRANSITIONING TO
ALL SNOW THIS EVENING. WITH INCREASING CONFIDENCE IN MEASURABLE
PRECIP I INCREASED POPS TO LIKELY CATEGORY ACROSS THE CENTRAL PART
OF THE CWA IN LINE WITH MODEL CONSENSUS. THERE IS STILL WEAK
INSTABILITY ADVERTISED WITH SNOW BAND...AND WITH STRONG FRONTOGENESIS
IMMEDIATELY BEHIND SHORTWAVE WE COULD SEE NARROW BANDING. QPF AMOUNTS
ARE GENERALLY LIGHT...AND WITH MARGINAL MOISTURE ADVECTION AND THE
FAST NATURE OF THIS SYSTEM I AM ONLY ANTICIPATING AROUND ONE INCH OF
SNOWFALL AT THE MOST. ANY LINGERING SNOW SHOULD QUICKLY COME TO AN
END AROUND SUNRISE TUESDAY MORNING.
DRY CONDITIONS ARE THEN EXPECTED THROUGH THE REST OF THE DAY TUESDAY
WITH ONLY HIGH CLOUDS POSSIBLY LINGERING THROUGH THE DAY. AIR MASS
SHOULD BE COOLER THAN TODAY...THOUGH IMPACTS FROM SNOW PACK SHOULD
BE MINIMAL. WE COULD SEE IMPACT FROM SKY COVER...BUT FOR NOW I KEPT
FORECAST SIMILAR TO TODAY...WITH MID/UPPER 40S IN THE NORTHEAST TO
LOW 50S IN THE SOUTHWEST.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 224 AM MDT MON MAR 11 2013
IN THE EXTENDED (THUR-SUN)...MEDIUM RANGE MODELS BEGIN THE PERIOD IN
REASONABLE AGREEMENT WITH LARGE RIDGE CENTERED OVER THE
INTERMOUNTAIN WEST...BUT FAIRLY QUICKLY BECOME OUT OF PHASE WITH
EACH OTHER OVER THE WEEKEND LEADING TO A FAIRLY LOW CONFIDENCE
FORECAST FOR THE AREA. WHILE THERE DOES APPEAR TO BE SOME THREAT FOR
PRECIPITATION IN THE SATURDAY-SUNDAY PERIOD...POSSIBILITY STRETCHES
FOR SEVERAL PERIODS DUE TO DIFFERENCES IN MODEL TIMING/OVERALL
PATTERN. GIVEN OVERALL CONFIDENCE LOW...THINK TRYING TO PICK AN
SPECIFIC PERIOD TO ENHANCE POPS NOT WARRANTED ATTM AND WILL CONTINUE
DRY FORECAST FOR CWA.
FOR TEMPERATURES...CONFIDENCE REMAINS HIGH THAT TEMPERATURES WILL
WARM INTO THE 70S THROUGH FRIDAY BUT WITH AFOREMENTIONED
CONCERNS...THINK KEEPING TEMPS AROUND CONSENSUS VALUES WARRANTED FOR
REST OF PERIOD DUE TO UNCERTAINTY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1134 AM MDT MON MAR 11 2013
VFR CONDITIONS EXPECTED TO PREVAIL THROUGH THIS EVENING AT BOTH
TERMINALS. MVFR CONDITIONS WILL DEVELOP OVER KGLD AT A BAND OF
RAIN/SNOW DEVELOPS LATE THIS AFTERNOON AND EVENING OVER EASTERN
COLORADO AND SPREADS INTO NORTHWEST KANSAS AS ALL SNOW TONIGHT. I
COULDNT RULE OUT BRIEF IFR CONDITIONS ALONG MOST INTENSE PART OF
SNOW BAND TONIGHT...HOWEVER I WAS NOT CONFIDENT ENOUGH TO PREVAIL
OR INCLUDE TEMPO GROUP...SINCE LOCATION OF THIS BAND IS STILL IN
QUESTION. CHANCE ARE LOWER FOR PRECIP/MVFR AT AT THE KMCK
TERMINAL SO CURRENTLY HAVE VFR CONTINUING WITH VCSH. VFR
CONDITIONS SHOULD PREVAIL AT BOTH TERMINALS AFTER 12Z WHEN PRECIP
QUICKLY MOVES EAST.
WINDS HAVE BEEN SLOWER TO INCREASE AT BOTH TERMINALS TODAY WITH
THICK HIGH CLOUDS OVERHEAD.I STILL EXPECT WIND GUSTS AROUND 20KT
BY MID AFTERNOON...DECREASING AROUND SUNSET. GUSTY WEST WINDS
SHOULD REDEVELOP AROUND 15Z TUESDAY WITH CLEARING SKIES AND BETTER
DAYTIME MIXING.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...JRM
AVIATION...DR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
637 PM EDT MON MAR 11 2013
.UPDATE...
ISSUED AT 636 PM EDT MON MAR 11 2013
PER WATER VAPOR IMAGERY...SHORTWAVE LIFTING N THRU WRN LWR MI IS
LOOKING INCREASINGLY IMPRESSIVE...AND IR IMAGERY SHOWS RAPIDLY
COOLING CLOUD TOPS THRU NRN LWR MI AS DEEP LAYER FORCING
STRENGTHENS. AS A RESULT...RADAR IMAGERY SHOWS EXPANDING PCPN ACROSS
NRN LWR MI. HAVE INCREASED POPS TO CATEGORICAL OVER THE FAR ERN FCST
AREA FOR SEVERAL HRS THIS EVENING AS EXPANDING/INTENSIFYING PCPN
SHIELD LIFTS N. COLUMN SHOULD RAPIDLY COOL...GIVING A QUICK
TRANSITION FROM MOSTLY LIQUID TO SNOW AS PCPN ARRIVES. INCLUDED 1-2
INCH SNOW AMOUNTS ACROSS LUCE COUNTY...BUT WILL NEED TO MONITOR
TRENDS CLOSELY OVER THE NEXT FEW HRS AS IT`S NOT OUT OF THE QUESTION
THAT THIS COULD TURN INTO AN ADVY TYPE SNOW EVENT OVER THE FAR E
GIVEN THE STRENGTHENING SHORTWAVE.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 426 PM EDT MON MAR 11 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW AN UPR TROF OVER
CENTRAL AND ERN NAMERICA. NEGATIVELY TILTED CLOSED LO OVER THE LOWER
GRT LKS IS TENDING TO LIFT TO THE NE AS ANOTHER SHRTWV DROPPING THRU
SCENTRAL CANADA DIGS INTO THE NRN PLAINS. THE SFC LO ASSOCIATED WITH
THIS DISTURBANCE HAS PUSHED TO NEAR MANISTIQUE AS OF MID AFTN. SFC
TEMPS AT ISQ/ERY HAVE RISEN INTO THE MID/UPR 30S TO THE E OF THE SFC
LO...AND THERE IS SOME FOG HERE WITH THE DRY AIR MOVING OVER
LINGERING LLVL MSTR. THE ARRIVAL OF THE DRY SLOT ASSOCIATED WITH THE
UPR LO HAS ENDED MOST OF THE PCPN EXCEPT OVER THE WRN COUNTIES...
WHICH LIE UNDER THE DEFORMATION ZN ON THE CYC SIDE OF THE H7 LO
TRACK. PERIODS OF SN HAVE BEEN MOST PERSISTENT IN THESE AREAS
TDAY...WITH SN FALL RATES UP TO 0.5-0.75 INCH/HR. ALTHOUGH THE DRY
SLOT HAS SWEPT THRU THE CNTRL COUNTIES...SOME -SN CONTINUES OVER
MAINLY NCENTRAL MQT COUNTY WITH CYC UPSLOPE N WIND PROVIDING
SUFFICIENT LIFT. ANOTHER AREA OF -SHRASN ASSOCIATED WITH THE
DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THE UPR LO IS APRCHG THE SE
COUNTIES...BUT PRESENCE OF LARGER SCALE DRY SLOT LOOKS TO BE
LIMITING THE COVERAGE TO SCT -SHRASN. TO THE W...12Z YPL/INL RAOBS
SHOW A DRIER/MORE STABLE AIRMASS IS PRESENT OVHD TO THE W OF THE
DEFORMATION ZN IN MN...AND THERE IS LTL PCPN FALLING THERE. ALTHOUGH
A FAIRLY IMPRESSIVE COMMA CLD APPEARS ASSOCIATED WITH THE SHRTWV
DIGGING INTO THE NRN PLAINS...PCPN APPEARS TO BE CONFINED TO AN AREA
NEAR LK WINNIPEG RIGHT UNDER THE COMMA HEAD.
MAIN FCST CONCERNS TNGT ARE SN TRENDS/GOING HEADLINES. FOCUS FOR TUE
SHIFTS TO POTENTIAL IMPACT OF SHRTWV DIGGING INTO THE NRN PLAINS.
TNGT...MODELS SHOW SFC LO LIFTING NEWD INTO SE ONTARIO TNGT...BUT
CLOSED LO/DEEPER MSTR TENDING TO LINGER OVER THE UPR LKS DESPITE
ARRIVAL OF DEEP LYR QVECTOR DVGC BY 06Z. AREA OF -SHRASN LIFTING NWD
THRU LK MI AHEAD OF THE UPR LO WL IMPACT THE ERN ZNS THIS EVNG WITH
AREAS OF FOG LINGERING THERE UNTIL SFC LO PASSES TO THE NE THIS EVNG
AND COLDER AIR ARRIVES. SUSPECT LINGERING DEFORMATION ZN PCPN OVER
THE WRN CWA WL SLOWLY DIMINISH WITH ARRIVAL OF THE NEGATIVE
FORCING...SO ENDED THE GOING HEADLINES AS SCHEDULED 00Z TO 06Z FM SW
TO NE. DOWNGRADED THE WARNINGS FOR BARAGA/MQT COUNTIES VALID THRU 0Z
WITH BULK OF PCPN EXPECTED TO FALL FARTHER W ON CYC SIDE OF H7 LO
TRACK. EVEN THOUGH THE STEADY SN WL TEND TO DIMINISH OVER THE
W...CYC NW FLOW OF AIR/ARRIVAL OF COLDER AIR WITH H85 TEMPS PROGGED
TO SINK AS LO AS -14C TO -15C BY 12Z TUE WL CAUSE NMRS SHSN TO
PERSIST. BUT CONCERNED LO INVRN HGTS/DRY MID LVL AIR SHOWN ON THE
12Z INL/YPL RAOBS WL LIMIT THE COVERAGE/INTENSITY OF THE SHSN...SO
WENT NO HIER THAN LIKELY POPS FOR NOW.
TUE...DISTURBANCE MOVING THRU THE NRN PLAINS/ACCOMPANYING DEEP LYR
QVECTOR CNVGC IS PROGGED TO MOVE TOWARD THE CWA...SO MAINTAINED
GOING INCRSG POPS TO CATEGOCIAL NEAR LK SUP BY LATE AFTN WITH FAIRLY
SHARP CYC NW FLOW ACTING AS AN ENHANCEMENT FACTOR IN THE PRESENCE OF
DEEPER MSTR/H85 TEMPS NOT FAR FM -15C. SINCE FCST SDNGS SHOW THE DGZ
SEVERAL THOUSAND FEET DEEP IN THE CONVECTIVE LYR...CONCERNED SOME
ADVY INTENSITY LES MIGHT OCCUR LATER IN THE DAY...ESPECIALLY IN THE
UPSLOPE AREAS OVER THE W.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 426 PM EDT MON MAR 11 2013
WITH AN UPPER LOW JUST E OF THE CWA AT 00Z WED AND A SFC TROUGH OVER
LAKE SUPERIOR...850MB TEMPS WILL BE AROUND -14 WITH CYCLONIC NW-NNW
LOW LEVEL WINDS. THESE CONDITIONS WILL BE FAVORABLE FOR LES TUE
NIGHT...WITH WARMING TEMPS VERY DRY LOW LEVEL AIR MOVING IN WITH A
SFC RIDGE LATE TUE NIGHT INTO WED NIGHT. EXPECT A RELATIVELY QUICK
BURST OF MODERATE LES ALONG AND JUST BEHIND THE SFC TROUGH THAT MAY
BRING A QUICK 2-4 INCHES OF SNOW OVER THE FAVORED HIGHER TERRAIN.
WITH THE RATE THAT THE VERY DRY AIR MOVES IN LATE TUE NIGHT...LES
WILL QUICKLY WEAKEN...AND SHOULD BE ALMOST COMPLETELY GONE BY 15Z
WED /IF NOT A BIT EARLIER/. MODELS THEN INDICATE AN AREA OF
INCREASED LOW LEVEL MOISTURE AND INCREASED LAKE INDUCED EQUILIBRIUM
LEVELS MOVING ACROSS CENTRAL LAKE SUPERIOR ALONG A WEAK SFC TROUGH
WED NIGHT. WILL KEEP SLIGHT CHANCE POPS E OF MARQUETTE AS CONDITIONS
WILL STILL ONLY BE MARGINAL FOR LES. ELSEWHERE WED NIGHT...CLEARING
OVER THE INTERIOR W SHOULD ALLOW MIN TEMPS TO FALL TO NEAR ZERO.
A COUPLE OF SHORTWAVES LOOK TO MOVE NEARBY THU/THU NIGHT...BUT
CONSENSUS OF MODELS PLACES BEST FORCING AND PRECIP N AND S OF THE
CWA...SO WILL KEEP ANY POPS ON THE LOW SIDE.
ANOTHER SHORTWAVE...BACKED UP BY THE LEFT EXIT REGION OF A 120+KT
JET...MOVES THROUGH FRI INTO FRI NIGHT. MODEL VARY WITH TIMING...BUT
GENERALLY AGREE ON OVERALL EXTENT/STRENGTH OF THE SYSTEM. MODELS
PAINT A QUARTER TO A THIRD OF AN INCH OF QPF...AND THE BEST OMEGA
LOOKS TO BE JUST BELOW AND INTO THE DGZ...WHICH SHOULD KEEP SNOW TO
LIQUID RATIOS FROM GETTING TOO LOW. STILL DIFFICULT TO SAY GIVEN
VOLATILE NATURE OF SHORTWAVES THAT FAR OUT...BUT COULD SEE A FEW
INCHES OF SNOW ACROSS THE AREA. 850MB TEMPS AOB -14C AND N-NW FLOW
BEHIND THE SYSTEM WOULD BRING SOME ADDITIONAL LES INTO SAT /AND
POSSIBLY BEYOND BUT TOO UNCERTAIN IN ANY DETAILS THAT FAR OUT TO
MENTION OR ADD TO THE FORECAST/.
HIGHS TEMPS WILL BE IN THE 20S ON WED...WITH A WARM UP TO AROUND 30
ON THU AND INTO THE MID 30S ON FRI. TEMPS LOOK TO DECREASE GOING
INTO THE WEEKEND AND EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 149 PM EDT MON MAR 11 2013
WINTER STORM STILL OVER NORTHERN UPR MICHIGAN...SO EXPECT POOR
FLYING CONDITIONS TO CONTINUE. NNE WINDS TURN NNW TONIGHT. HEAVIER
SNOW WITH MID-LEVEL LOW WILL CONTINUE AT IWD AND CMX INTO THIS
EVENING. THEN...LK EFFECT SNOWS WITH IFR VSBY AND MVFR CIGS SHOULD
CONTINUE THROUGH REST OF TAF PERIOD DUE TO LINGERING COOL AND MOIST
FLOW THROUGH LOWEST 5KFT. AT SAW...CONDITIONS WILL IMPROVE STEADILY
THROUGH LATE AFTN THROUGH TONIGHT AS HEAVIER SNOW REMAINS WEST THIS
AFTN AND LK EFFECT DEVELOPING TONIGHT WILL NOT BE AS FAVORABLE WITH
MORE OF A NW COMPONENT TO WIND. EVEN SO...PLENTY OF LINGERING
MOISTURE AND CYCLONIC LOW-LEVEL WINDS SHOULD RESULT IN MVFR
CONDITIONS INTO TUESDAY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 426 PM EDT MON MAR 11 2013
EXPECT SLOWLY DIMINISHING NNE WINDS TO BACK TO THE NW TNGT INTO TUE
AS SFC LO OVER ERN UPR MI THIS EVNG MOVES NEWD THRU ONTARIO TOWARD
JAMES BAY. EVEN THOUGH WINDS WL BE SLOWLY DIMINISHING...THE ARRIVAL
OF COLDER AIR WL RESULT IN SOME FREEZING SPRAY.
A TROUGH WILL MOVE THROUGH LATE TUESDAY AND TUESDAY NIGHT...CAUSING
WINDS TO GUST NEAR 35KTS OVER CENTRAL AND EASTERN LAKE SUPERIOR.
WINDS RELAX WEDNESDAY AND WEDNESDAY NIGHT AS A RIDGE MOVES THROUGH.
BEHIND THE RIDGE. WINDS WILL REMAIN BELOW 20KTS THROUGH THE REST OF
THE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 11 PM EDT THIS EVENING FOR MIZ004-
005.
WINTER STORM WARNING UNTIL 11 PM EDT THIS EVENING FOR MIZ002-084.
WINTER STORM WARNING UNTIL 2 AM EDT TUESDAY FOR MIZ003.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT TUESDAY FOR MIZ001.
WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR MIZ009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...ROLFSON
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...JLA
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
430 PM EDT MON MAR 11 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 426 PM EDT MON MAR 11 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW AN UPR TROF OVER
CENTRAL AND ERN NAMERICA. NEGATIVELY TILTED CLOSED LO OVER THE LOWER
GRT LKS IS TENDING TO LIFT TO THE NE AS ANOTHER SHRTWV DROPPING THRU
SCENTRAL CANADA DIGS INTO THE NRN PLAINS. THE SFC LO ASSOCIATED WITH
THIS DISTURBANCE HAS PUSHED TO NEAR MANISTIQUE AS OF MID AFTN. SFC
TEMPS AT ISQ/ERY HAVE RISEN INTO THE MID/UPR 30S TO THE E OF THE SFC
LO...AND THERE IS SOME FOG HERE WITH THE DRY AIR MOVING OVER
LINGERING LLVL MSTR. THE ARRIVAL OF THE DRY SLOT ASSOCIATED WITH THE
UPR LO HAS ENDED MOST OF THE PCPN EXCEPT OVER THE WRN COUNTIES...
WHICH LIE UNDER THE DEFORMATION ZN ON THE CYC SIDE OF THE H7 LO
TRACK. PERIODS OF SN HAVE BEEN MOST PERSISTENT IN THESE AREAS
TDAY...WITH SN FALL RATES UP TO 0.5-0.75 INCH/HR. ALTHOUGH THE DRY
SLOT HAS SWEPT THRU THE CNTRL COUNTIES...SOME -SN CONTINUES OVER
MAINLY NCENTRAL MQT COUNTY WITH CYC UPSLOPE N WIND PROVIDING
SUFFICIENT LIFT. ANOTHER AREA OF -SHRASN ASSOCIATED WITH THE
DPVA/DEEP LYR QVECTOR CNVGC AHEAD OF THE UPR LO IS APRCHG THE SE
COUNTIES...BUT PRESENCE OF LARGER SCALE DRY SLOT LOOKS TO BE
LIMITING THE COVERAGE TO SCT -SHRASN. TO THE W...12Z YPL/INL RAOBS
SHOW A DRIER/MORE STABLE AIRMASS IS PRESENT OVHD TO THE W OF THE
DEFORMATION ZN IN MN...AND THERE IS LTL PCPN FALLING THERE. ALTHOUGH
A FAIRLY IMPRESSIVE COMMA CLD APPEARS ASSOCIATED WITH THE SHRTWV
DIGGING INTO THE NRN PLAINS...PCPN APPEARS TO BE CONFINED TO AN AREA
NEAR LK WINNIPEG RIGHT UNDER THE COMMA HEAD.
MAIN FCST CONCERNS TNGT ARE SN TRENDS/GOING HEADLINES. FOCUS FOR TUE
SHIFTS TO POTENTIAL IMPACT OF SHRTWV DIGGING INTO THE NRN PLAINS.
TNGT...MODELS SHOW SFC LO LIFTING NEWD INTO SE ONTARIO TNGT...BUT
CLOSED LO/DEEPER MSTR TENDING TO LINGER OVER THE UPR LKS DESPITE
ARRIVAL OF DEEP LYR QVECTOR DVGC BY 06Z. AREA OF -SHRASN LIFTING NWD
THRU LK MI AHEAD OF THE UPR LO WL IMPACT THE ERN ZNS THIS EVNG WITH
AREAS OF FOG LINGERING THERE UNTIL SFC LO PASSES TO THE NE THIS EVNG
AND COLDER AIR ARRIVES. SUSPECT LINGERING DEFORMATION ZN PCPN OVER
THE WRN CWA WL SLOWLY DIMINISH WITH ARRIVAL OF THE NEGATIVE
FORCING...SO ENDED THE GOING HEADLINES AS SCHEDULED 00Z TO 06Z FM SW
TO NE. DOWNGRADED THE WARNINGS FOR BARAGA/MQT COUNTIES VALID THRU 0Z
WITH BULK OF PCPN EXPECTED TO FALL FARTHER W ON CYC SIDE OF H7 LO
TRACK. EVEN THOUGH THE STEADY SN WL TEND TO DIMINISH OVER THE
W...CYC NW FLOW OF AIR/ARRIVAL OF COLDER AIR WITH H85 TEMPS PROGGED
TO SINK AS LO AS -14C TO -15C BY 12Z TUE WL CAUSE NMRS SHSN TO
PERSIST. BUT CONCERNED LO INVRN HGTS/DRY MID LVL AIR SHOWN ON THE
12Z INL/YPL RAOBS WL LIMIT THE COVERAGE/INTENSITY OF THE SHSN...SO
WENT NO HIER THAN LIKELY POPS FOR NOW.
TUE...DISTURBANCE MOVING THRU THE NRN PLAINS/ACCOMPANYING DEEP LYR
QVECTOR CNVGC IS PROGGED TO MOVE TOWARD THE CWA...SO MAINTAINED
GOING INCRSG POPS TO CATEGOCIAL NEAR LK SUP BY LATE AFTN WITH FAIRLY
SHARP CYC NW FLOW ACTING AS AN ENHANCEMENT FACTOR IN THE PRESENCE OF
DEEPER MSTR/H85 TEMPS NOT FAR FM -15C. SINCE FCST SDNGS SHOW THE DGZ
SEVERAL THOUSAND FEET DEEP IN THE CONVECTIVE LYR...CONCERNED SOME
ADVY INTENSITY LES MIGHT OCCUR LATER IN THE DAY...ESPECIALLY IN THE
UPSLOPE AREAS OVER THE W.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 426 PM EDT MON MAR 11 2013
WITH AN UPPER LOW JUST E OF THE CWA AT 00Z WED AND A SFC TROUGH OVER
LAKE SUPERIOR...850MB TEMPS WILL BE AROUND -14 WITH CYCLONIC NW-NNW
LOW LEVEL WINDS. THESE CONDITIONS WILL BE FAVORABLE FOR LES TUE
NIGHT...WITH WARMING TEMPS VERY DRY LOW LEVEL AIR MOVING IN WITH A
SFC RIDGE LATE TUE NIGHT INTO WED NIGHT. EXPECT A RELATIVELY QUICK
BURST OF MODERATE LES ALONG AND JUST BEHIND THE SFC TROUGH THAT MAY
BRING A QUICK 2-4 INCHES OF SNOW OVER THE FAVORED HIGHER TERRAIN.
WITH THE RATE THAT THE VERY DRY AIR MOVES IN LATE TUE NIGHT...LES
WILL QUICKLY WEAKEN...AND SHOULD BE ALMOST COMPLETELY GONE BY 15Z
WED /IF NOT A BIT EARLIER/. MODELS THEN INDICATE AN AREA OF
INCREASED LOW LEVEL MOISTURE AND INCREASED LAKE INDUCED EQUILIBRIUM
LEVELS MOVING ACROSS CENTRAL LAKE SUPERIOR ALONG A WEAK SFC TROUGH
WED NIGHT. WILL KEEP SLIGHT CHANCE POPS E OF MARQUETTE AS CONDITIONS
WILL STILL ONLY BE MARGINAL FOR LES. ELSEWHERE WED NIGHT...CLEARING
OVER THE INTERIOR W SHOULD ALLOW MIN TEMPS TO FALL TO NEAR ZERO.
A COUPLE OF SHORTWAVES LOOK TO MOVE NEARBY THU/THU NIGHT...BUT
CONSENSUS OF MODELS PLACES BEST FORCING AND PRECIP N AND S OF THE
CWA...SO WILL KEEP ANY POPS ON THE LOW SIDE.
ANOTHER SHORTWAVE...BACKED UP BY THE LEFT EXIT REGION OF A 120+KT
JET...MOVES THROUGH FRI INTO FRI NIGHT. MODEL VARY WITH TIMING...BUT
GENERALLY AGREE ON OVERALL EXTENT/STRENGTH OF THE SYSTEM. MODELS
PAINT A QUARTER TO A THIRD OF AN INCH OF QPF...AND THE BEST OMEGA
LOOKS TO BE JUST BELOW AND INTO THE DGZ...WHICH SHOULD KEEP SNOW TO
LIQUID RATIOS FROM GETTING TOO LOW. STILL DIFFICULT TO SAY GIVEN
VOLATILE NATURE OF SHORTWAVES THAT FAR OUT...BUT COULD SEE A FEW
INCHES OF SNOW ACROSS THE AREA. 850MB TEMPS AOB -14C AND N-NW FLOW
BEHIND THE SYSTEM WOULD BRING SOME ADDITIONAL LES INTO SAT /AND
POSSIBLY BEYOND BUT TOO UNCERTAIN IN ANY DETAILS THAT FAR OUT TO
MENTION OR ADD TO THE FORECAST/.
HIGHS TEMPS WILL BE IN THE 20S ON WED...WITH A WARM UP TO AROUND 30
ON THU AND INTO THE MID 30S ON FRI. TEMPS LOOK TO DECREASE GOING
INTO THE WEEKEND AND EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 149 PM EDT MON MAR 11 2013
WINTER STORM STILL OVER NORTHERN UPR MICHIGAN...SO EXPECT POOR
FLYING CONDITIONS TO CONTINUE. NNE WINDS TURN NNW TONIGHT. HEAVIER
SNOW WITH MID-LEVEL LOW WILL CONTINUE AT IWD AND CMX INTO THIS
EVENING. THEN...LK EFFECT SNOWS WITH IFR VSBY AND MVFR CIGS SHOULD
CONTINUE THROUGH REST OF TAF PERIOD DUE TO LINGERING COOL AND MOIST
FLOW THROUGH LOWEST 5KFT. AT SAW...CONDITIONS WILL IMPROVE STEADILY
THROUGH LATE AFTN THROUGH TONIGHT AS HEAVIER SNOW REMAINS WEST THIS
AFTN AND LK EFFECT DEVELOPING TONIGHT WILL NOT BE AS FAVORABLE WITH
MORE OF A NW COMPONENT TO WIND. EVEN SO...PLENTY OF LINGERING
MOISTURE AND CYCLONIC LOW-LEVEL WINDS SHOULD RESULT IN MVFR
CONDITIONS INTO TUESDAY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 426 PM EDT MON MAR 11 2013
EXPECT SLOWLY DIMINISHING NNE WINDS TO BACK TO THE NW TNGT INTO TUE
AS SFC LO OVER ERN UPR MI THIS EVNG MOVES NEWD THRU ONTARIO TOWARD
JAMES BAY. EVEN THOUGH WINDS WL BE SLOWLY DIMINISHING...THE ARRIVAL
OF COLDER AIR WL RESULT IN SOME FREEZING SPRAY.
A TROUGH WILL MOVE THROUGH LATE TUESDAY AND TUESDAY NIGHT...CAUSING
WINDS TO GUST NEAR 35KTS OVER CENTRAL AND EASTERN LAKE SUPERIOR.
WINDS RELAX WEDNESDAY AND WEDNESDAY NIGHT AS A RIDGE MOVES THROUGH.
BEHIND THE RIDGE. WINDS WILL REMAIN BELOW 20KTS THROUGH THE REST OF
THE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 11 PM EDT THIS EVENING FOR MIZ004-
005.
WINTER STORM WARNING UNTIL 11 PM EDT THIS EVENING FOR MIZ002-084.
WINTER STORM WARNING UNTIL 2 AM EDT TUESDAY FOR MIZ003.
WINTER WEATHER ADVISORY UNTIL 2 AM EDT TUESDAY FOR MIZ001.
WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR MIZ009.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...JLA
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS DULUTH MN
317 PM CDT MON MAR 11 2013
.SHORT TERM...CWA REMAINS UNDER THE INFLUENCE OF A CYCLONIC
CIRCULATION TO THE EAST OF THE REGION. ORGANIZED FORCING IN THE
FORM OF WEAK FRONTOGENESIS HAS KEPT MORE PERSISTENT SNOW OVER ERN
EDGE OF REGION. ELSEWHERE...ABUNDANT CLOUD COVER AND A FEW
FLURRIES ARE OCCURRING.
TONIGHT...AN AMPLIFYING MID LVL SYSTEM WILL TRACK FROM SRN
MANITOBA TO JUST SOUTH OF THE BRD LAKES VICINITY. IT IS DIFFICULT
TO FIND MUCH IN THE WAY OF A SFC REFLECTION ASSOCIATED WITH THIS
FEATURE EITHER IN THE PRESSURE OR WIND FIELDS. USED A BLEND OF THE
SREF AND EC TO KEEP POPS FOCUSED IN TWO AREAS. FIRST...ACROSS THE
SRN TIER OF ZONES CLOSER TO TRACK OF UPPER FEATURE. SECOND...AS
COLDER AIR MOVES ACROSS LAKE SUPERIOR...SOME INCREASE IN LES MAY
OCCUR OVER ERN WISC SNOWBELTS.
TOMORROW...UPPER LOW SCOOTS QUICKLY SE OF REGION BY MIDDAY WITH
DEEPENING OF NRLY FLOW ACROSS CWA. MOST PROBABLE AREAS FOR PRECIP
WILL BE OVER ARROWHEAD AND WISC SNOWBELTS. A WRAPAROUND LOBE OF
DEEP LAYER MOISTURE ASSOCIATED WITH A MIGRATORY SHORTWAVE TROF
WILL ROTATE WESTWARD INTO ARROWHEAD DURING THE DAY. THIS IS
REFLECTED IN THE EC AND THE SPC WRF/NMM. 85H THERMAL TROUGH
SETTLES SOUTHWARD ACROSS LAKE SUPERIOR IN THE AFTERNOON. NEARLY
UNIDIRECTIONAL FLOW IN SFC/85H LAYER COMBINED WITH INCREASINGLY
FAVORABLE SYNOPTIC SCALE MOISTURE WILL PROMOTE ADDITIONAL SNOW
INTO SNOWBELTS. MAY NEED TO CONSIDER AN ADVISORY FOR LATE
AFTERNOON INTO EVENING.
TUESDAY NIGHT THROUGH MONDAY.
THE NORTHLAND WILL CONTINUE TO BE INFLUENCED BY A TROUGH TUESDAY
NIGHT...WITH SOME LIGHT SNOW OR FLURRIES WILL LINGERING TUESDAY
EVENING...BUT DIMINISHING OVERNIGHT. LITTLE ACCUMULATION IS EXPECTED
FOR MOST AREAS. THE EXCEPTION WILL BE ALONG THE SOUTH SHORE...MAINLY
THE SNOWBELT REGION OF ASHLAND/IRON COUNTIES. CHANCES FOR LAKE
EFFECT SNOW SHOWERS LOOK PRETTY GOOD WITH NORTHERLY WINDS AND 850MB
TEMPERATURES DROPPING TO AROUND -14C TO -16C. WE INCREASED POPS AND
SNOW AMOUNTS ACROSS ASHLAND/IRON COUNTIES TUESDAY NIGHT...WITH THE
BEST CHANCE FROM 00Z WED TO ABOUT 09Z WED. INVERSION LEVELS DROP
LATE AND DRIER AIR MOVES OVER THE LAKE LATE TUESDAY NIGHT AND
THROUGH WEDNESDAY. WINDS WILL ALSO BACK WEDNESDAY. AN ADVISORY MAY
BE NEEDED FOR IRON AND ASHLAND COUNTIES.
A WEST NORTHWEST FLOW WILL PREVAIL THROUGH MOST OF THE REST OF
PERIOD WITH SEVERAL SHORTWAVES MOVING THROUGH AND BRINGING PERIODIC
CHANCES FOR PRECIPITATION. MOST OF THE SHORTWAVES WILL ONLY BRING
LIGHT PRECIPITATION.
WE HAVE A CHANCE FOR LIGHT SNOW WEDNESDAY NIGHT INTO THURSDAY AS WAA
MOVES THROUGH THE AREA. THE PRECIP LOOKS RATHER LIGHT...AND PRECIP
TYPE COULD BE IN QUESTION. 850MB TEMPS ARE FORECAST TO RISE TO
AROUND +4C OVER OUR SOUTHWEST ZONES BY 00Z FRI...AND REMAIN AROUND
-4C FAR NORTHEAST. FORECAST SOUNDINGS ALSO SHOW THE MOIST LAYER IS
RATHER LIMITED...WITH ICE CRYSTAL PRESENCE IN QUESTION. LATER SHIFTS
MAY HAVE TO ADD SOME MIXED PRECIP ONCE WE GET CLOSER.
A MORE SIGNIFICANT CLIPPER SYSTEM IS FORECAST BY THE ECMWF TO AFFECT
THE NORTHLAND FRIDAY INTO FRIDAY NIGHT...WITH THE GFS ABOUT 12 HOURS
FASTER. A MIX COULD BE POSSIBLE ONCE AGAIN...ESPECIALLY OVER THE
SOUTHERN HALF. A FEW INCHES OF SNOW WILL BE POSSIBLE WITH THIS
SYSTEM. THE GFS SHOWS THE CORE OF THE PRECIPITATION FURTHER NORTH
THAN THE ECMWF. BOTH THE GFS AND ECMWF DO SHOW COLDER AIR MOVING IN
BEHIND THIS CLIPPER...LASTING INTO THE WEEKEND.
HIGH TEMPERATURES WILL RANGE FROM THE UPPER TWENTIES TO LOWER
THIRTIES WEDNESDAY. THEY WILL WARM INTO THE LOWER TO MID THIRTIES
THURSDAY/FRIDAY...AND COOL A BIT BEHIND THE CLIPPER OVER THE WEEKEND.
.AVIATION...18Z TAFS
MIX OF MVFR AND LOW VFR CONDITIONS COVERED THE NORTHLAND EARLY
THIS AFTERNOON...WITH SOME LIGHT SNOW OR FLURRIES IN SPOTS.
OVERALL...WE EXPECT THESE CONDITIONS TO CONTINUE THROUGH THE
PERIOD. THE RUC 900-925MB PRESSURE DEFICITS WERE INDICATING SOME
DECREASE IN CLOUD COVER THIS EVENING...BUT JUST DON`T HAVE THE
CONFIDENCE TO DIMINISH CEILINGS TOO MUCH. A CLIPPER MAY SPREAD
ADDITIONAL CLOUDS AND PERHAPS SOME ADDITIONAL LIGHT SNOW TO THE
REGION TONIGHT.
.POINT TEMPS/POPS...
DLH 15 29 11 30 / 20 30 10 0
INL 11 27 6 29 / 20 20 10 0
BRD 16 29 10 30 / 30 30 10 10
HYR 16 30 12 32 / 30 60 20 10
ASX 16 29 15 30 / 30 60 30 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...CANNON
LONG TERM....MELDE
AREA FORECAST DISCUSSION
NWS DULUTH MN
123 PM CDT MON MAR 11 2013
.AVIATION...18Z TAFS
MIX OF MVFR AND LOW VFR CONDITIONS COVERED THE NORTHLAND EARLY
THIS AFTERNOON...WITH SOME LIGHT SNOW OR FLURRIES IN SPOTS.
OVERALL...WE EXPECT THESE CONDITIONS TO CONTINUE THROUGH THE
PERIOD. THE RUC 900-925MB PRESSURE DEFICITS WERE INDICATING SOME
DECREASE IN CLOUD COVER THIS EVENING...BUT JUST DON`T HAVE THE
CONFIDENCE TO DIMINISH CEILINGS TOO MUCH. A CLIPPER MAY SPREAD
ADDITIONAL CLOUDS AND PERHAPS SOME ADDITIONAL LIGHT SNOW TO THE
REGION TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 1009 AM CDT MON MAR 11 2013/
UPDATE...INCREASED SKY COVERAGE ACROSS MOST OF THE ERN CWA WITH
SLOWER CLEARING TREND INDICATED BY SAT IMAGERY. AREA OF CLEARING
OVER WRN CWA MAY BE SHORT LIVED AS MID LVL MOISTURE FROM NEXT
SYSTEM IS APPROACHING WRN BORDER ALREADY. FLURRIES WILL REMAIN
NEAR TWIN PORTS UNTIL MIDDAY WHEN RELAXING OF CIRCULATION FROM ERN
SYSTEM BEGINS. BDRY LYR FLOW BACKS MORE NRLY THIS AFTERNOON OVER
WISCONSIN. INCREASED POPS OVER ERN WISC ZONES REMAINDER OF MORNING
AS LATEST SPC MESOANALYSIS...AND 88D RETURNS...SHOWS A DEFORMATION
AXIS STRETCHING ACROSS PRICE COUNTY. WILL INCREASE SNOW
ACCUMULATIONS TO 1 TO 3 INCHES.
PREV DISCUSSION... /ISSUED 307 AM CDT MON MAR 11 2013/
SHORT TERM...TODAY AND TONIGHT. THE MAIN FOCUS FOR THE SHORT
TERM IS THE SNOW IN EASTERN AREAS OF THE NW WI FORECAST AREA.
CURRENT SURFACE AND RADAR ANALYSIS INDICATE MODERATE SNOW FALLING
ACROSS AREAS EAST OF A LINE FROM IRONWOOD THROUGH GLIDDEN. VSBYS
HAVE RANGED FROM 1/2 TO 1 MILE AT PBH AND IRONWOOD THE PAST TWO
HOURS. NAM HAD HAD MORE SNOWFALL WITH SYSTEM THAN THE GFS/ECMWF
BUT THE SREF HAS BEEN CLOSER THE PAST COUPLE OF RUNS WITH
PLACEMENT. AS INDICATED BY PREVIOUS SHIFT...THE NAM CROSS
SECTIONS SHOW GOOD SATURATION/UPWARD MOTION IN THE DENDRITIC EARLY
THIS MORNING THROUGH 12Z. IT WILL BE CLOSE...BUT SOME AREA IN
SOUTHERN PRICE COUNTY COULD SEE 6 INCHES. THE OTHER COUNTIES IN
THE ADVISORY HAVE SOME SNOW BANDS OVER THEM SO THE 3-5 INCHES LOOK
GOOD. WILL KEEP CURRENT HEADLINES UP THROUGH 17Z AS PLANNED. THE
SNOW WILL TAPER OFF TO LIGHT SNOW BY EARLY THIS AFTERNOON AS THE
LOW MOVES OFF TO THE NORTHEAST. WILL ALSO HAVE FLURRIES IN THE
REST OF FCST AREA THIS MORNING AS SFC OBS HAVE BEEN REPORTING THEM.
EXTENDED...TUESDAY THROUGH MONDAY. IT IS LOOKING A BIT DRIER FOR
TUESDAY NOW THAN IT HAS OVER THE PAST SEVERAL RUNS. THE MODELS
GENERALLY AGREE ON FAIRLY DRY AIR ENTRAINMENT INTO THE CWA BEHIND
DEPARTING LOW PRESSURE. THE BEST CHANCE OF LIGHT SNOW WOULD BE ALONG
THE SOUTH SHORE OF LAKE SUPERIOR. ANOTHER STRONGER SHORTWAVE SHOULD
MOVE GENERALLY SOUTH OF THE CWA TUESDAY AND TUESDAY NIGHT. HIGH
PRESSURE WILL BUILD IN ON WEDNESDAY BRINGING A BIT OF SUNSHINE TO
THE NORTHLAND. ANOTHER SHOT OF LIGHT SNOW IS POSSIBLE ON THURSDAY
BUT ONLY LOW POPS WARRANTED FOR RELATIVELY WEAK WAA EVENT. A BETTER
SNOWFALL EVENT IS EXPECTED TO ARRIVE ON FRIDAY AND LINGER INTO
SATURDAY AND EVEN A BIT INTO SATURDAY NIGHT. HAVE RAISED POPS INTO
THE HIGH CHANCE CATEGORY BUT WILL LIKELY NEED TO CONTINUE TO TREND
TOWARD A LIKELY TYPE WORDING. COOL HIGH PRESSURE WILL THEN BUILD IN
FOR THE REMAINDER OF THE WEEKEND WITH SOME SCATTERED LIGHT SNOW
SHOWERS BY MONDAY. OVERALL WE ARE LOOKING AT TEMPERATURES IN THE 30S
FOR THE MOST PART...WITH SOME 40S LATE IN THE WEEK AND INTO THE
UPCOMING WEEKEND. SHOULD BE A GOOD RUN OF DAYTIME MELTING AND
NIGHTTIME COOLING WHICH WOULD BE GOOD FOR SPRING SNOWMELT ISSUES.
&&
.POINT TEMPS/POPS...
DLH 15 29 12 31 / 20 20 10 0
INL 11 27 8 30 / 20 20 10 0
BRD 16 29 11 30 / 30 30 10 10
HYR 16 30 13 33 / 30 30 20 10
ASX 16 29 16 31 / 30 40 30 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1242 PM CDT MON MAR 11 2013
.SYNOPSIS...
ISSUED AT 404 AM CDT MON MAR 11 2013
WATER VAPOR IMAGERY AT 08Z SHOWED A DEEP TROUGH OVER THE CENTRAL
CONUS WHICH EXTENDED INTO BAJA CALIFORNIA...WITH THE UPPER LEVEL LOW
CENTERED OVER IOWA. SNOW CONTINUED TO FALL WITH THIS SYSTEM OVER
EASTERN NEBRASKA EARLY THIS MORNING...HOWEVER MOST IMPACTS HAD
SHIFTED EAST OF THE STATE. STRONG RIDGING WAS OBSERVED DOWNSTREAM
OVER THE EAST COAST...WHILE ANOTHER BROAD RIDGE WAS SEEN OVER THE
EASTERN PACIFIC AND WESTERN CONUS. THERE WAS A WEAK SHORTWAVE
TROUGH OVER MONTANA THIS MORNING AS TOP OF THE RIDGE WAS FAIRLY
FLATTENED. AT THE SURFACE...THE PRESSURE GRADIENT HAD FINALLY
WEAKENED AS THE SURFACE LOW WITH THE SYSTEM TO THE EAST PULLED OFF
INTO ILLINOIS AND WISCONSIN. THIS LEFT WINDS TO DIMINISH
OVERNIGHT...WHILE A SURFACE TROUGH WAS ANALYZED ON THE LEE SIDE OF
THE ROCKIES WITH BREEZY WESTERLY WINDS IN ITS WAKE. WITH WEAK HIGH
PRESSURE OVER THE FORECAST AREA...TEMPERATURES OVERNIGHT HAVE
DROPPED SIGNIFICANTLY...INTO THE SINGLE DIGITS AND TEENS.
&&
.UPDATE...
ISSUED AT 1107 AM CDT MON MAR 11 2013
INCREASED MAX TEMPERATURES TODAY ACROSS MY SOUTHEAST ZONES INTO
THE UPPER 40S. TEMPERATURES HAVE QUICKLY WARMED THIS MORNING IN
AREAS OF MINIMAL SNOW COVER. DID NOT TAKE AN AGGRESSIVE APPROACH
WITH CONTINUED WARMING THIS AFTERNOON SINCE NORTHWEST WINDS WILL
MOVE OVER THE DENSE SNOW PACK FROM OGA TO VTN...WHICH MAY HAMPER
TEMPERATURES BY A FEW DEGREES.
ALSO ADJUSTED POP FIELDS FOR THIS AFTERNOON AND EVENING. H7 FRONT
SHOWING UP WELL ON IR SATELLITE...EXTENDING FROM CENTRAL MONTANA
SOUTHEAST INTO NORTHEAST COLORADO. EXPECT THIS TO BE THE PRIMARY FOCUS
FOR SNOW SHOWERS LATER TODAY INTO THE OVERNIGHT HOURS AS COLDER
AIR MOVES SOUTH IN ADVANCE OF THE SHORTWAVE TROUGH CURRENTLY IN
EASTERN MONTANA.
UPDATE ISSUED AT 715 AM CDT MON MAR 11 2013
A NEW FORECAST IS OUT. LOOKING AT THE RAP MODEL SOUNDINGS AND THE
K INDEXES OF ALL MODELS SUGGESTS REASONABLE POTENTIAL FOR
CONVECTION THIS AFTERNOON...MAINLY OFF THE BLACK HILLS AND IN THE
PANHANDLE WHERE MOISTURE WILL BE DEEPEST AND LAPSE RATES STEEPEST.
WE MAY EVEN SEE A BREAKAWAY STORM MOVE AS FAR SOUTH AS I-80 LATE
THIS AFTN OR THIS EVENING. THE NAM INDICATED POTENTIAL FOR TSTMS
BUT GIVEN THE ISOLATED COVERAGE IT IS PROBABLY NOT WORTH MENTION.
OTHERWISE RAIN AND SNOW SHOWERS UNTIL EARLY EVENING THEN SNOW
SHOWERS.
WINDS STAY UP TONIGHT SO LOWS SHOULD BE IN THE 20S MOST AREAS. THE
MODELS ARE SUGGESTING A BLEND OF PACIFIC AND ARCTIC MOVING IN
TONIGHT AND HOLDING ON THROUGH TUESDAY. HIGH TEMPERATURES TUESDAY
HAVE BEEN MARKED DOWN TO 30S TO LOWER 40S AS SUGGESTED BY A
MULTIMODEL BLEND OF BIAS DATA.
WINDS TODAY AND TUESDAY WILL REACH 20 TO 30 MPH...ACROSS THE WEST
TODAY AND THE NORTHEAST TUESDAY.
&&
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 404 AM CDT MON MAR 11 2013
A MULTIMODEL BLEND OF THE GEM...NAM...GFS AND ECM WHICH ARE ALL
PRETTY CLOSE WITH LOW PRESSURE DROPPING THROUGH THE MISSOURI BASIN
SETTING OFF ISOLATED RAIN OR SNOW SHOWERS THIS AFTERNOON. FARTHER
WEST...LAPSE RATES STEEPEN LATE THIS AFTERNOON AND THIS EVENING. A
COLD FRONT DROPS THROUGH THE HIGH PLAINS ACTING AS A FOCUS FOR RAIN
AND SNOW SHOWERS.
WINDS INCREASE TO 15 TO 30 MPH THIS AFTERNOON AND REMAIN
SUFFICIENTLY STRONG TO PREVENT THE DEVELOPMENT OF A SFC INVERSION
TONIGHT. SO TEMPS TONIGHT SHOULD REMAIN MOSTLY IN THE 20S...A FEW
TEENS IN THE NORTHWEST WHERE HIGH PRESSURE WILL SETTLE IN SOMEWHAT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 404 AM CDT MON MAR 11 2013
THE FORECAST FOCUS THROUGH THIS PERIOD IS WITH TEMPERATURES...AS
WELL AS PRECIPITATION CHANCES THROUGH THE WEEKEND.
THE TUESDAY THROUGH FRIDAY PERIOD IS FAIRLY STRAIGHT FORWARD THIS
FORECAST CYCLE AS MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE
UPPER LEVEL PATTERN AND SURFACE FEATURES.
THE RIDGE OFF THE EAST COAST WILL STAY FIRMLY IN PLACE THROUGH
MID-WEEK WHICH WILL KEEP AN UPPER LEVEL TROUGH CENTERED OVER THE
MISSISSIPPI AND OHIO VALLEYS. MEANWHILE...ENERGY ASSOCIATED WITH THE
SHORTWAVE TROUGH CURRENTLY OVER MONTANA WILL BE MOVING OUT OF THE
NORTHERN AND CENTRAL PLAINS ON TUESDAY AND INTO THE PRIMARY TROUGH
TO THE EAST. ANY PRECIPITATION EXPECTED FOR MONDAY NIGHT SHOULD
END BY TUESDAY MORNING AS ANY FORCING FOR PRECIPITATION
DEVELOPMENT WANES ACROSS THE LOCAL AREA. ALTHOUGH THE FORECAST
AREA WILL BE IN NORTHWEST FLOW BEHIND THIS SHORTWAVE...SLIGHT WARM
AIR ADVECTION WILL BE ONGOING THROUGH THE DAY...AND WITH SKIES
EXPECTED TO CLEAR AS HIGH PRESSURE BUILD IN...TEMPERATURES WILL BE
ON A WARMING TREND. SHOULD STILL SEE IMPACTS ON HIGHS ON TUESDAY
FROM THE SNOWPACK...WHICH IS QUITE SUBSTANTIAL IN PARTS OF THE
FORECAST AREA.
THE UPPER LEVEL TROUGH OVER THE OHIO VALLEY WILL FINALLY SHIFT
FURTHER EASTWARD THROUGH THURSDAY ALLOWING THE RIDGE OVER THE WEST
TO BUILD INTO THE PLAINS. THIS WILL BRING SIGNIFICANT WARM AIR
ADVECTION TO THE REGION AS TEMPERATURES AT 850MB ARE BEING SHOWN
TO RISE INTO THE MID AND UPPER TEENS BY FRIDAY EVENING. SNOW MELT
WILL BE IN FULL SWING BY WEDNESDAY AND BY THURSDAY AND FRIDAY
DON/T EXPECT MUCH IMPACT ON TEMPERATURES. ALTHOUGH MODELS AREN/T
SHOWING REAL STRONG WINDS WEDNESDAY THROUGH FRIDAY...THOUGHTS ARE
THAT WITH THE WARMING EXPECTED...WILL GET DECENT MIXING TO BRING
DOWN SOME STRONGER WINDS FROM ALOFT SO DID INCREASE THE WIND
SPEEDS SLIGHTLY. DIDN/T GO QUITE AS WARM AS SOME MODELS WOULD
SUGGEST...AS SOME GUIDANCE WAS GIVING MID TO UPPER 70S FOR FRIDAY.
STUCK WITH UPPER 50S AND 60S FOR THURSDAY AND 60S TO LOW 70S FOR
FRIDAY.
THINGS WILL COOL OFF FOR THE WEEKEND AS THE MODELS ARE SHOWING A
SWITCH IN THE UPPER LEVEL PATTERN. THIS BEING SAID...THERE ARE
CONSIDERABLE DIFFERENCES IN THE MODEL SOLUTIONS THROUGH THE
WEEKEND SO CONFIDENCE ON THIS PORTION OF THE FORECAST IS FAIRLY
LOW. THERE LOOKS TO BE A CHANCE FOR SOME PRECIPITATION ACROSS THE
AREA AT SOME POINT DURING THE WEEKEND...BUT WITH THE
INCONSISTENCIES AND LOW CONFIDENCE IN MODEL SOLUTIONS...TRIED TO
PICK OUT THE PERIODS AND LOCATIONS WITH THE HIGHER PROBABILITIES TO
INCLUDE PRECIPITATION CHANCES IN THE FORECAST AT THIS POINT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1245 PM CDT MON MAR 11 2013
NO AVIATION CONCERNS OVER THE NEXT 24 HOURS. CONDITIONS WILL
REMAIN VFR ACROSS MOST OF WESTERN NEBRASKA. SNOW SHOWERS WILL BE
POSSIBLE IN THE EASTERN PANHANDLE AND FAR SOUTHWEST NEBRASKA THIS
EVENING AND TONIGHT...WHICH MAY CLIP KLBF. DUE TO LOW FORECASTER
CONFIDENCE HAVE LEFT ANY MENTION OF -SN OUT OF THE TAF FOR NOW.
MONITORING POSSIBILITY OF FOG AT KVTN OVERNIGHT ON TOP OF FRESH
SNOW PACK. HOWEVER WINDS ARE EXPECTED TO REMAIN ELEVATED THROUGH
THE OVERNIGHT HOURS WHICH WOULD ALL BUT ELIMINATE CHANCES OF FOG
FORMATION. TRENDS WILL BE MONITORED AND AMENDMENTS WILL BE MADE IF
NECESSARY.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MARTIN
SYNOPSIS...BROOKS
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...MARTIN
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1108 AM CDT MON MAR 11 2013
.SYNOPSIS...
ISSUED AT 404 AM CDT MON MAR 11 2013
WATER VAPOR IMAGERY AT 08Z SHOWED A DEEP TROUGH OVER THE CENTRAL
CONUS WHICH EXTENDED INTO BAJA CALIFORNIA...WITH THE UPPER LEVEL LOW
CENTERED OVER IOWA. SNOW CONTINUED TO FALL WITH THIS SYSTEM OVER
EASTERN NEBRASKA EARLY THIS MORNING...HOWEVER MOST IMPACTS HAD
SHIFTED EAST OF THE STATE. STRONG RIDGING WAS OBSERVED DOWNSTREAM
OVER THE EAST COAST...WHILE ANOTHER BROAD RIDGE WAS SEEN OVER THE
EASTERN PACIFIC AND WESTERN CONUS. THERE WAS A WEAK SHORTWAVE
TROUGH OVER MONTANA THIS MORNING AS TOP OF THE RIDGE WAS FAIRLY
FLATTENED. AT THE SURFACE...THE PRESSURE GRADIENT HAD FINALLY
WEAKENED AS THE SURFACE LOW WITH THE SYSTEM TO THE EAST PULLED OFF
INTO ILLINOIS AND WISCONSIN. THIS LEFT WINDS TO DIMINISH
OVERNIGHT...WHILE A SURFACE TROUGH WAS ANALYZED ON THE LEE SIDE OF
THE ROCKIES WITH BREEZY WESTERLY WINDS IN ITS WAKE. WITH WEAK HIGH
PRESSURE OVER THE FORECAST AREA...TEMPERATURES OVERNIGHT HAVE
DROPPED SIGNIFICANTLY...INTO THE SINGLE DIGITS AND TEENS.
&&
.UPDATE...
ISSUED AT 1107 AM CDT MON MAR 11 2013
INCREASED MAX TEMPERATURES TODAY ACROSS MY SOUTHEAST ZONES INTO
THE UPPER 40S. TEMPERATURES HAVE QUICKLY WARMED THIS MORNING IN
AREAS OF MINIMAL SNOW COVER. DID NOT TAKE AN AGGRESSIVE APPROACH
WITH CONTINUED WARMING THIS AFTERNOON SINCE NORTHWEST WINDS WILL
MOVE OVER THE DENSE SNOW PACK FROM OGA TO VTN...WHICH MAY HAMPER
TEMPERATURES BY A FEW DEGREES.
ALSO ADJUSTED POP FIELDS FOR THIS AFTERNOON AND EVENING. H7 FRONT
SHOWING UP WELL ON IR SATELLITE...EXTENDING FROM CENTRAL MONTANA
SOUTHEAST INTO NORTHEAST COLORADO. EXPECT THIS TO BE THE PRIMARY FOCUS
FOR SNOW SHOWERS LATER TODAY INTO THE OVERNIGHT HOURS AS COLDER
AIR MOVES SOUTH IN ADVANCE OF THE SHORTWAVE TROUGH CURRENTLY IN
EASTERN MONTANA.
UPDATE ISSUED AT 715 AM CDT MON MAR 11 2013
A NEW FORECAST IS OUT. LOOKING AT THE RAP MODEL SOUNDINGS AND THE
K INDEXES OF ALL MODELS SUGGESTS REASONABLE POTENTIAL FOR
CONVECTION THIS AFTERNOON...MAINLY OFF THE BLACK HILLS AND IN THE
PANHANDLE WHERE MOISTURE WILL BE DEEPEST AND LAPSE RATES STEEPEST.
WE MAY EVEN SEE A BREAKAWAY STORM MOVE AS FAR SOUTH AS I-80 LATE
THIS AFTN OR THIS EVENING. THE NAM INDICATED POTENTIAL FOR TSTMS
BUT GIVEN THE ISOLATED COVERAGE IT IS PROBABLY NOT WORTH MENTION.
OTHERWISE RAIN AND SNOW SHOWERS UNTIL EARLY EVENING THEN SNOW
SHOWERS.
WINDS STAY UP TONIGHT SO LOWS SHOULD BE IN THE 20S MOST AREAS. THE
MODELS ARE SUGGESTING A BLEND OF PACIFIC AND ARCTIC MOVING IN
TONIGHT AND HOLDING ON THROUGH TUESDAY. HIGH TEMPERATURES TUESDAY
HAVE BEEN MARKED DOWN TO 30S TO LOWER 40S AS SUGGESTED BY A
MULTIMODEL BLEND OF BIAS DATA.
WINDS TODAY AND TUESDAY WILL REACH 20 TO 30 MPH...ACROSS THE WEST
TODAY AND THE NORTHEAST TUESDAY.
&&
.SHORT TERM...(TODAY THROUGH MONDAY NIGHT)
ISSUED AT 404 AM CDT MON MAR 11 2013
A MULTIMODEL BLEND OF THE GEM...NAM...GFS AND ECM WHICH ARE ALL
PRETTY CLOSE WITH LOW PRESSURE DROPPING THROUGH THE MISSOURI BASIN
SETTING OFF ISOLATED RAIN OR SNOW SHOWERS THIS AFTERNOON. FARTHER
WEST...LAPSE RATES STEEPEN LATE THIS AFTERNOON AND THIS EVENING. A
COLD FRONT DROPS THROUGH THE HIGH PLAINS ACTING AS A FOCUS FOR RAIN
AND SNOW SHOWERS.
WINDS INCREASE TO 15 TO 30 MPH THIS AFTERNOON AND REMAIN
SUFFICIENTLY STRONG TO PREVENT THE DEVELOPMENT OF A SFC INVERSION
TONIGHT. SO TEMPS TONIGHT SHOULD REMAIN MOSTLY IN THE 20S...A FEW
TEENS IN THE NORTHWEST WHERE HIGH PRESSURE WILL SETTLE IN SOMEWHAT.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 404 AM CDT MON MAR 11 2013
THE FORECAST FOCUS THROUGH THIS PERIOD IS WITH TEMPERATURES...AS
WELL AS PRECIPITATION CHANCES THROUGH THE WEEKEND.
THE TUESDAY THROUGH FRIDAY PERIOD IS FAIRLY STRAIGHT FORWARD THIS
FORECAST CYCLE AS MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE
UPPER LEVEL PATTERN AND SURFACE FEATURES.
THE RIDGE OFF THE EAST COAST WILL STAY FIRMLY IN PLACE THROUGH
MID-WEEK WHICH WILL KEEP AN UPPER LEVEL TROUGH CENTERED OVER THE
MISSISSIPPI AND OHIO VALLEYS. MEANWHILE...ENERGY ASSOCIATED WITH THE
SHORTWAVE TROUGH CURRENTLY OVER MONTANA WILL BE MOVING OUT OF THE
NORTHERN AND CENTRAL PLAINS ON TUESDAY AND INTO THE PRIMARY TROUGH
TO THE EAST. ANY PRECIPITATION EXPECTED FOR MONDAY NIGHT SHOULD
END BY TUESDAY MORNING AS ANY FORCING FOR PRECIPITATION
DEVELOPMENT WANES ACROSS THE LOCAL AREA. ALTHOUGH THE FORECAST
AREA WILL BE IN NORTHWEST FLOW BEHIND THIS SHORTWAVE...SLIGHT WARM
AIR ADVECTION WILL BE ONGOING THROUGH THE DAY...AND WITH SKIES
EXPECTED TO CLEAR AS HIGH PRESSURE BUILD IN...TEMPERATURES WILL BE
ON A WARMING TREND. SHOULD STILL SEE IMPACTS ON HIGHS ON TUESDAY
FROM THE SNOWPACK...WHICH IS QUITE SUBSTANTIAL IN PARTS OF THE
FORECAST AREA.
THE UPPER LEVEL TROUGH OVER THE OHIO VALLEY WILL FINALLY SHIFT
FURTHER EASTWARD THROUGH THURSDAY ALLOWING THE RIDGE OVER THE WEST
TO BUILD INTO THE PLAINS. THIS WILL BRING SIGNIFICANT WARM AIR
ADVECTION TO THE REGION AS TEMPERATURES AT 850MB ARE BEING SHOWN
TO RISE INTO THE MID AND UPPER TEENS BY FRIDAY EVENING. SNOW MELT
WILL BE IN FULL SWING BY WEDNESDAY AND BY THURSDAY AND FRIDAY
DON/T EXPECT MUCH IMPACT ON TEMPERATURES. ALTHOUGH MODELS AREN/T
SHOWING REAL STRONG WINDS WEDNESDAY THROUGH FRIDAY...THOUGHTS ARE
THAT WITH THE WARMING EXPECTED...WILL GET DECENT MIXING TO BRING
DOWN SOME STRONGER WINDS FROM ALOFT SO DID INCREASE THE WIND
SPEEDS SLIGHTLY. DIDN/T GO QUITE AS WARM AS SOME MODELS WOULD
SUGGEST...AS SOME GUIDANCE WAS GIVING MID TO UPPER 70S FOR FRIDAY.
STUCK WITH UPPER 50S AND 60S FOR THURSDAY AND 60S TO LOW 70S FOR
FRIDAY.
THINGS WILL COOL OFF FOR THE WEEKEND AS THE MODELS ARE SHOWING A
SWITCH IN THE UPPER LEVEL PATTERN. THIS BEING SAID...THERE ARE
CONSIDERABLE DIFFERENCES IN THE MODEL SOLUTIONS THROUGH THE
WEEKEND SO CONFIDENCE ON THIS PORTION OF THE FORECAST IS FAIRLY
LOW. THERE LOOKS TO BE A CHANCE FOR SOME PRECIPITATION ACROSS THE
AREA AT SOME POINT DURING THE WEEKEND...BUT WITH THE
INCONSISTENCIES AND LOW CONFIDENCE IN MODEL SOLUTIONS...TRIED TO
PICK OUT THE PERIODS AND LOCATIONS WITH THE HIGHER PROBABILITIES TO
INCLUDE PRECIPITATION CHANCES IN THE FORECAST AT THIS POINT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 620 AM CDT MON MAR 11 2013
VFR IS GENERALLY EXPECTED TODAY AND TONIGHT AS A MIX OF MID AND
HIGH CLOUDS MOVE SOUTHEAST OFF THE HIGH PLAINS. THERE IS
OPPORTUNITY FOR MVFR CIGS IN ISOLATED TO SCATTERED RAIN AND SNOW
SHOWERS...MAINLY LATE THIS AFTERNOON AND THIS EVENING ACROSS NRN
AND WRN NEB. THE MODELS OFFER SOME DIVERSE SOLNS TO THIS EVENT.
SOME DEVELOP CONVECTION ACROSS NRN NEB AROUND NOON WHILE OTHERS
WAIT TILL LATE AFTERNOON AND SOME SOLNS SHOW NO CONVECTION AT ALL
ACROSS NRN NEB.
THERE IS A GOOD CONSENSUS FOR ACTIVITY DEVELOPING OFF THE BLACK
HILLS LATE THIS AFTERNOON AND ACROSS THE NEB PANHANDLE. THIS
ACTIVITY WILL MOVE SOUTH SOUTHEAST. IN FACT THERE COULD EVEN BE AN
ISOLATED LIGHTNING STRIKE OR TWO ACROSS SHERIDAN AND CHERRY
COUNTIES LATE THIS AFTERNOON.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MARTIN
SYNOPSIS...BROOKS
SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
358 PM EDT MON MAR 11 2013
.SYNOPSIS...
A SLOW-MOVING COLD FRONT WILL APPROACH FROM THE WEST TONIGHT AND
TUESDAY AND MOVE OFFSHORE TUESDAY NIGHT. HIGH PRESSURE WILL BUILD
IN FROM THE WEST WEDNESDAY AND LINGER ACROSS THE AREA BEFORE MOVING
OFFSHORE ON SATURDAY. ANOTHER COLD FRONT WILL APPROACH THE REGION
SUNDAY AND MOVE OFFSHORE BY MONDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 330 PM MONDAY...AFTER A VERY WARM AFTERNOON WITH HIGH
TEMPERATURES AT OR ABOVE 70 DEGREES AT MANY LOCATIONS...CLOUDS
WILL INCREASE OVERNIGHT AS LOW-LEVEL MOISTURE IS ADVECTED INTO THE
REGION WITH A INCREASING SE SURFACE FLOW. THE CLOUDS AND WINDS
SHOULD HOLD MINIMUM TEMPERATURES IN THE MILD MIDDLE AND UPPER 50S
TONIGHT. THE 4KM WRF...ARW AND RAP MODELS KEEP MOST OF THE
SIGNIFICANT PRECIPITATION WEST OF OUR CWA THROUGH ABOUT
MIDNIGHT...ALTHOUGH A FEW LIGHT WARM ADVECTION LIGHT SHOWERS OR
SPRINKLES MAY OCCUR LATER THIS EVENING.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
AS OF 330 PM MON...THERE IS STILL SOME CONCERN ON TUESDAY ABOUT A
MINIMAL THREAT OF SEVERE WEATHER IN A WINDOW DURING THE MORNING
AND EARLY AFTERNOON. STRONG LOW-LEVEL SSE/S WINDS ARE EXPECTED
WITH GOOD LOW-LEVEL SHEAR VALUES AND THE AREA IN A RIGHT ENTRANCE
REGION OF AN UPPER LEVEL JET STREAK. LOW LEVEL (0-3 KM) HELICITY
VALUES ARE FORECAST TO BE AS HIGH AS 300 M2/S2 DURING THE EARLY
PART OF TUESDAY...HOWEVER CAPE VALUES LOOK TO MINIMAL WITH
FORECAST LI`S OF ONLY ABOUT -1 PER FORECAST SOUNDINGS. THINK THE
THREAT OF ANY THUNDER ENDS DURING THE MID-AFTERNOON AS THE COLD
FRONT MOVES OFFSHORE IN THE EARLY EVENING. LOOKS LIKE MOST AREAS
WILL RECEIVE ROUGHLY ONE HALF INCH OF RAIN TUESDAY. TEMPERATURES
WILL RISE INTO THE MIDDLE 60S TO LOWER 70S FOR HIGHS ON TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
AS OF 300 PM MONDAY...MED RANGE MODELS IN DECENT AGREEMENT THROUGH
FRIDAY...THEN DIVERGE FOR SAT-MON. INITIAL SHRT WV AND ASSCTD SFC
FRONT WILL MOVE OFFSHORE TUE EVENING...FOLLOWED BY DRIER AND COLDER
CONDITIONS FOR WED-THU NIGHT. UPPER FLOW THEN BECOMES MORE ZONAL FOR
WEEKEND LEADING TO MODERATING TEMPS...BUT SOME MODEL DIFFERENCES ON
HOW FAR SOUTH A EAST-WEST ORIENTED FRONT WILL PUSH SAT-MON. LEANED
TO HPC SOLUTION WITH FRONT REMAINING JUST N OF AREA...BUT CONFIDENCE
IS LOW. KEPT POPS TO JUST SLIGHT CHC FOR SAT NIGHT AND SUN WITH CHC
ON MONDAY.
UPR TROFFING WILL LEAD TO BELOW NORMAL TEMPS INTO FRIDAY...WITH THU
THE COLDEST DAY WITH HIGHS ONLY NEAR 50 INLAND. TEMPS FCST TO
MODERATE BACK INTO 60S SAT AND CONTINUE NEAR OR SLIGHTLY ABOVE
NORMAL SUN-MON...BUT WILL BE DEPENDENT ON FRONTAL LOCATION. IF FRONT
PUSHES THROUGH AND STALLS S OF AREA...TEMPS COULD BE 5-10 DEGS
COOLER.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
SHORT TERM /THROUGH TUESDAY AFTERNOON /...
AS OF 130 PM MON...VFR CONDITIONS WILL CONTINUE THROUGH MUCH OF
THE EVENING AS A FRONT APPROACHES THE REGION TONIGHT. THE FRONT
WILL SLOWLY CROSS THE AREA TOMORROW AFTERNOON WITH RAIN AHEAD OF
ACTUAL BOUNDARY. AS MOIST SOUTHERLY FLOW INCREASES
TONIGHT...ANTICIPATE SOME SHOWERS TO MOVE INLAND FROM OFF THE
WATER AHEAD OF THE MAIN LINE OF PRECIPITATION. CEILINGS WILL BEGIN
TO SLOWLY LOWER TONIGHT AND WILL EVENTUALLY BECOME MVFR BY EARLY
TOMORROW MORNING. THE HEAVIER PRECIPITATION SHOULD CROSS THE TAF
SITES BETWEEN 12Z-18Z. THEREFORE...ANTICIPATE CEILINGS TO DROP TO
IFR CRITERIA...ALBEIT BRIEFLY. RAIN SHOULD TAPPER OFF BY TOMORROW
LATE AFTERNOON. EXPECT ANY THUNDERSTORM ACTIVITY WILL OCCUR
CLOSER TO THE COAST WITH BETTER INSTABILITY. CEILINGS WILL SCATTER
OUT TOMORROW EVENING AS DRIER AIR ADVECTS ACROSS THE AREA.
LONG TERM /TUE NIGHT THROUGH SATURDAY/...
AS OF 300 PM MONDAY...VFR EXPECTED TO RETURN TUE NIGHT IN WAKE OF
COLD FRONT MOVING OFF COAST...THEN PREVAILING THROUGH SAT WITH DRY
HIGH PRES GRADUALLY BUILDING OVER AREA FROM NW.
&&
.MARINE...
SHORT TERM /TONIGHT AND TUESDAY/...
AS OF 335 PM MONDAY...WINDS ARE PRETTY UNIFORM ON THE COASTAL
WATERS AND SOUNDS THIS AFTERNOON WITH ESE/SE WINDS OF 10 TO 15
KNOTS. SEAS CONTINUE ROUGH...ESPECIALLY OVER THE NORTHERN WATERS
WITH 7 TO 10 FEET WITH CONTINUED LONG PERIOD SWELLS. SEAS HAVE
SUBSIDED SOMEWHAT ON THE SOUTHERN WATERS...BUT SHOULD INCREASE
FROM THE SE/S TONIGHT AS GRADIENT IS PINCHED AS A COLD FRONT
SLOWLY APPROACHES FROM THE WEST. GUSTY SOUTH WINDS OF 20 TO 25
KNOTS WITH A FEW GUSTS TO 30 KNOTS ARE EXPECTED ON TUESDAY IN
ADVANCE OF THE FRONT WHICH SHOULD MOVE OFFSHORE DURING THE EARLY
EVENING HOURS. NO CHANGES MADE TO CURRENT HEADLINES.
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 300 PM MONDAY...WIND SHIFT TO NW WILL FOLLOW FRONTAL PASSAGE
TUE EVENING WITH INITIAL CAA SURGE GENERALLY LESS THAN 20 KT EARLY
WED. STRONGER SURGE WITH GUSTS TO AROUND 25 KT WILL DEVELOP WED
EVENING WITH PASSAGE OF MAIN UPR TROF AND CONTINUE INTO THU NIGHT.
FLOW WILL THEN DIMINISH AND BACK TO W FRI AND FRI NIGHT AS HIGH PRES
MOVES ACROSS TO S.
LONG PERIOD SWELL FROM E-NE WILL GRADUALLY SUBSIDE DURING
PERIOD...BUT MODERATE TO STRONG NW WINDS WITH CAA SURGE WILL PRODUCE
SEAS TO AROUND 6 FT OVER OUTER PORTIONS INTO THU. SEAS FINALLY
EXPECTED TO SUBSIDE BELOW 6 FT FRIDAY...BUT MAY BUILD TO 6 FT SRN
PORTIONS LATE SAT WITH INCREASING SW WINDS.
&&
.TIDES/COASTAL FLOODING...
AS OF 340 PM MONDAY...HAVE EXTENDED THE HIGH SURF ADVISORY UNTIL 1
AM TONIGHT GIVEN CONTINUES LARGE SWELLS AND REPORTS OF ROADWAY
ISSUES ALONG HIGHWAY 12 OVER THE OUTER BANKS.
LARGE HIGH-ENERGY WAVES FROM A DEEP LOW PRESSURE SYSTEM OVER THE
NORTHWESTERN ATLANTIC WILL CONTINUE TO BRING HIGH SURF CONDITIONS
AND PERIODS OF OCEAN OVERWASH ACROSS THE OBX NORTH OF CAPE
HATTERAS THROUGH THIS EVENING. SEAS ARE SLOWLY COMING DOWN BUT
WILL STILL LIKELY HAVE BREAKERS OF 8 FT OR GREATER THIS EVENING.
HIGHWAY 12 HAS BEEN IMPACTED BY SIGNIFICANT OVERWASH ESPECIALLY
AT HIGH TIDE AND PORTIONS HAVE BEEN CLOSED AT TIMES NEAR MIRLO AND
SHOULD CONTINUE INTO THIS EVENING.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...HIGH SURF ADVISORY UNTIL 1 AM EDT TUESDAY FOR NCZ103.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT FRIDAY FOR AMZ150-152-154.
SMALL CRAFT ADVISORY UNTIL NOON EDT THURSDAY FOR AMZ156-158.
&&
$$
SYNOPSIS...CTC
NEAR TERM...CTC
SHORT TERM...CTC
LONG TERM...JBM
AVIATION...LEP/JBM/CTC
MARINE...JBM/CTC
TIDES/COASTAL FLOODING...CTC
AREA FORECAST DISCUSSION
NWS BISMARCK ND
328 PM CDT MON MAR 11 2013
.SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT...
MAIN HIGHLIGHT IN THE SHORT TERM IS A WINTER WEATHER ADVISORY
ACROSS THE NORTH...AND THE JAMES RIVER VALLEY MONDAY NIGHT
THROUGH EARLY TUESDAY MORNING.
THE LATEST SURFACE MAP SHOWS A STRONG COLD FRONT STRETCHING FROM
NEAR LAKE WINNIPEG SOUTHWEST INTO REGINA. A RATHER LARGE AREA OF
3HR MAX PRESSURE RISES OF 4MB WAS CENTERED OVER SOUTH CENTRAL
SASKATCHEWAN. NORTHWEST WINDS OF 25 TO 35 MPH ASSOCIATED WITH THIS
WERE OCCURRING OVER SEVERAL LOCATIONS...WITH VISIBILITIES RANGING
ANYWHERE FROM 3/4 OF A MILE TO 8 MILES. WITH RECENT SNOWFALL IN
THE NORTH AND THE JAMES RIVER VALLEY...IN COMBINATION WITH THE
GUSTY WINDS TO 35 MPH TONIGHT...SIGNIFICANT BLOWING AND DRIFTING
SNOW WILL CAUSE VISIBILITIES OF A MILE OR LESS AND HAZARDOUS
TRAVEL. THE LATEST RAP MODEL DRAGS THE CENTER OF THE PRESSURE RISE
AREA INTO NORTHERN NORTH DAKOTA BY 06Z AND INTO THE JAMES RIVER
VALLEY AT 12Z. SCATTERED SNOW SHOWERS WILL ACCOMPANY THE COLD
FRONT WITH ACCUMULATIONS OF AROUND ONE INCH. THIS WILL FURTHER ADD
TO THE REDUCTION IN VISIBILITIES AND HAZARDOUS TRAVEL OVERNIGHT
AND EARLY TUESDAY MORNING. DESPITE LARGE SCALE ASCENT ABSENT FROM
THIS SYSTEM...MOST OF THE SNOW SHOWERS WILL BE DRIVEN BY LOW LEVEL
INSTABILITY. DECENT LOW LEVEL LAPSE RATES ARE ACHIEVED AS THE COLD
H85 POCKET OF -12C TO -14C SLIDES INTO WESTERN AND CENTRAL NORTH
DAKOTA TONIGHT. AS MENTIONED ABOVE...SNOWFALL ACCUMULATIONS OF
AROUND ONE INCH POSSIBLE WITH THESE SNOW SHOWERS.
FOR TUESDAY...SCATTERED SNOW SHOWERS AND GUSTY WINDS LINGER IN THE
JAMES RIVER VALLEY DURING THE MORNING. OTHERWISE A COLDER DAY WITH
A 1032MB SURFACE HIGH PRESSURE ARRIVING IN NORTHWEST NORTH DAKOTA
BY 18Z WITH LIGHTER WINDS AND MORE SUNSHINE DEVELOPING FROM WEST
TO EAST. HIGHS TUESDAY WILL RANGE FROM 20 NORTH TO LOWER 30S
SOUTHWEST.
FOR TUESDAY NIGHT..WARM AIR ADVECTION ARRIVES IN THE WEST WITH
UPGLIDE/ASCENT ADVERTISED ON THE 285-295K PRESSURE SURFACES. THUS
HAVE SLIGHT CHANCE OF SNOW TUESDAY EVENING IN THE WEST FOLLOWED BY
A CHANCE AFTER MIDNIGHT. SNOWFALL AMOUNTS OF AROUND ONE HALF INCH
POSSIBLE TUESDAY NIGHT IN THE WEST.
.LONG TERM...WEDNESDAY THROUGH MONDAY NIGHT...
HIGHLIGHTS OF THE EXTENDED FORECAST ARE ABOVE AVERAGE TEMPERATURES
TO BEGIN THE PERIOD...WITH TEMPERATURES TRENDING POTENTIALLY BELOW
NORMAL LATE NEXT WEEK AND INTO THE WEEKEND. WIDESPREAD ACCUMULATING
SNOW IS ALSO POSSIBLE THURSDAY NIGHT INTO FRIDAY.
A WARM FRONT IS FORECAST TO PROPAGATE ACROSS WESTERN AND CENTRAL
NORTH DAKOTA THROUGH THE DAY ON WEDNESDAY. A RATHER LARGE
TEMPERATURE GRADIENT IS EXPECTED WITH HIGHS IN THE 20S AND LOWER 30S
OVER THE SNOWPACK AHEAD OF THE WARM FRONT...TO THE UPPER 50S ACROSS
THE SOUTHWEST WITH BARE GROUND. THE 12 UTC GFS BECOMES A CLEAR
OUTLIER FRIDAY ONWARDS AS IT IS THE DEEPEST AND FASTEST SOLUTION IN
REGARDS TO A SURFACE LOW ACROSS NORTHERN MONTANA THURSDAY
NIGHT...PROPAGATING INTO MINNESOTA ON FRIDAY. THUS...FOLLOWED THE 12
UTC ECMWF/GEM WHICH BUILD ARCTIC HIGH PRESSURE INTO NORTH DAKOTA
FRIDAY THROUGH THE WEEKEND. THESE MODELS ALSO HAVE SHOWN GOOD
TEMPERATURE VERIFICATION WITH BIAS CORRECTION APPLIED TO ACCOUNT
FOR THE FAIRLY CONSISTENT SNOW/SNOW FREE AREAS. THUS...ANOTHER LARGE
TEMPERATURE GRADIENT IS POSSIBLE THURSDAY WITH HIGHS IN THE 20S
NORTH TO THE LOWER 60S SOUTHWEST...WITH HIGHS 10 TO 20 DEGREES
COOLER FOR SATURDAY AS THE ARCTIC HIGH BUILDS IN. IN REGARDS TO
PRECIPITATION...WIDESPREAD ACCUMULATING SNOW IS POSSIBLE THURSDAY
NIGHT INTO FRIDAY WITH FRONTOGENESIS ASSOCIATED WITH THE BAROCLINIC
ZONE ON THE LEADING EDGE OF THE AFOREMENTIONED SURFACE HIGH.
&&
.AVIATION...AS OF 2030 UTC...A WEAK FRONT WAS ENTERING EASTERN NORTH DAKOTA.
STRONG NORTHWEST WINDS WITH GUSTS OF 25-30 KTS WERE OCCURRING BEHIND
THIS FRONT IN WESTERN AND CENTRAL NORTH DAKOTA. A SECOND...AND STRONGER
COLD FRONT LOCATED ACROSS SOUTHEAST SASKATCHEWAN WILL DROP SOUTH INTO
NORTH DAKOTA LATE THIS AFTERNOON AND THROUGH THE EVENING. EVEN STRONGER
GUSTS OF 30-40 KTS ARE EXPECTED BEHIND THIS FRONT WITH SCATTERED SNOW
SHOWERS. BLOWING SNOW IS ALSO A CONCERN AT KISN...KMOT AND KJMS THIS
EVENING AND TONIGHT...WITH IFR VISIBILITIES WHEN COMBINED WITH SNOW
SHOWERS POSSIBLE. OTHERWISE...MVFR CEILINGS ARE EXPECTED BEHIND THE
SECOND FRONT AS STRATUS OVERSPREADS THE AREA.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 1 AM TO 10 AM CDT TUESDAY FOR
NDZ021>023-025-036-037-047-048-050-051.
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 AM CDT
TUESDAY FOR NDZ001>005-009>013.
&&
$$
SHORT TERM...KS
LONG TERM/AVIATION...AYD