Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 03/25/13
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
742 PM MDT SUN MAR 24 2013
.UPDATE...THERE IS A BAND OF SNOW SINKING SOUTH ACROSS SOUTHERN
WELD...ADAMS AND ARAPAHOE COUNTIES. ADJUSTED FORECAST TO MATCH UP
WITH THIS AS IT SHIFTS SOUTH. OUTSIDE OF THIS AREA LOWERED POPS.
SATELLITE INDICATES SHOWERS ARE DECREASING. STILL EXPECT MOST OF
THE ACTIVITY TO END BY MIDNIGHT. A FEW LIGHT SNOW SHOWERS WILL
REMAIN POSSIBLE OVER THE MOUNTAINS AFTER MIDNIGHT AND WILL KEEP
LOW POPS IN FOR THIS. ANY SNOW THAT FALL WILL BE LIGHT...MAINLY
LESS THAN AN INCH. IT WILL BE ANOTHER COLD NIGHT WITH SINGLE
DIGITS EXPECTED ACROSS NORTHEAST COLORADO.
&&
.AVIATION...SNOW SHOWERS WILL REMAIN POSSIBLE THROUGH 06Z.
VISIBILITY WILL FALL TO AROUND ONE MILE WITH CEILINGS AS LOW AS
1500 FEET IN THE SNOW SHOWERS. OUTSIDE OF THE SNOW...CEILINGS
WILL BE 4000 TO 8000 FEET THROUGH 06Z...AND THEN RISE. IF ENOUGH
CLEARING TAKES PLACE LATE TONIGHT...CAN`T RULE OUT PATCHY FOG.
WINDS WILL TURN NORTHEASTERLY IN THE NEXT COUPLE OF HOURS. THEY
WILL BE LIGHT AFTER 06Z AND END UP SOUTHERLY.
&&
.PREV DISCUSSION... /ISSUED 237 PM MDT SUN MAR 24 2013/
..CORRECTED SPELLING ERRORS...
SHORT TERM...A DISTURBANCE IN NW FLOW ALOFT WILL MOVE ACROSS THE
AREA THIS EVENING AS A BNDRY BRIEFLY ENHANCES UPSLOPE FLOW ALONG
THE FRONT RANGE. LAPSE RATES IN AND NR THE FOOTHILLS WILL BE
AROUND 8 C/KM. THUS WOULD EXPECT SNOW SHOWER ACTIVITY THRU THE
EARLY EVENING HOURS. BOTH THE RAP AND HRRR ARE SHOWING AMOUNTS IN
THE FOOTHILLS WEST AND SOUTHWEST OF DENVER UP TO 4 INCHES WITH UP
TO 2 INCHES IN THE WRN SUBURBS. FURTHER EAST AMOUNTS ARE IN AN
INCH OR LESS. ANOTHER AREA OF SNOW MAY RESIDE NR THE WY-CO BORDER
IN NR WELD COUNTY WHERE AN INCH OR TWO MAY FALL. IN THE MTNS WILL
CONTINUE TO SEE SOME OROGRAPHIC -SHSN WITH A FEW INCHES POSSIBLE
AS WELL. BY MIDNIGHT MOST ACTIVITY SHOULD END ALTHOUGH RAP SHOWS
SHOW LIGHT ACTIVITY NR THE WY BORDER.
ON MON DRIER AIR WILL BE OVER THE AREA IN NW FLOW ALOFT HOWEVER
SOME LINGERING MOISTURE IN THE MTNS MAY ALLOW FOR A SLIGHT CHC OF
-SHSN. AS FOR TEMPS WITH SFC HIGH PRES STILL OVER THE AREA AND
LINGERING SNOWPACK WILL KEEP HIGHS MAINLY IN THE UPPER 20S TO
LOWER 30S ACROSS NERN CO.
LONG TERM...NORTHWESTERLY FLOW ALOFT IS TO DOMINATE THE FORECAST
AREA MONDAY NIGHT THROUGH TUESDAY...THEN UPPER RIDGING GETS OVER
THE STATE AND THE FLOW ALOFT IS ZONAL. THE SYNOPTIC SCALE ENERGY
PROGGED OVER THE CWA IS BENIGN ACCORDING TO THE Q-G VERTICAL
VELOCITY FIELDS MONDAY NIGHT THROUGH WEDNESDAY NIGHT. THE LOW
LEVEL WIND AND PRESSURE FIELDS SHOW NORMAL DIURNAL TRENDS
CONCERNING THE BOUNDARY LAYER WINDS MONDAY NIGHT THROUGH WEDNESDAY
NIGHT. MODELS HAVE LIMITED MOISTURE AROUND MONDAY NIGHT. ON
TUESDAY...MOISTURE INCREASES OVER THE MOUNTAINS AND IN THE MID AND
UPPER LEVELS OF THE PLAINS...ESPECIALLY ON THE GFS. THIS CONTINUE
INTO WEDNESDAY...BEFORE DRYING OUT SOMEWHAT WEDNESDAY NIGHT. THE QPF
FIELDS HAVE MINIMAL MEASURABLE PRECIPITATION NOTED...MOSTLY OVER THE
MOUNTAINS...TUESDAY AFTERNOON...THEN AGAIN WEDNESDAY INTO WEDNESDAY
EVENING. WILL GO WITH 20-40% POPS IN THE MOUNTAINS TUESDAY AFTERNOON
THROUGH WEDNESDAY EVENING. FOR TEMPERATURES... TUESDAY`S HIGHS ARE
ABOUT 6 C WARMER THAN MONDAY`S HIGHS. WEDENSDAY`S HIGHS ARE 1-3 C
WARMER THAN TUESDAY`S. FOR THE LATER DAYS...THURSDAY THROUGH
SUNDAY...NOW THE MODELS KEEP UPPER RIDGING OVER COLORADO ALL FOUR
DAYS. THE UPPER CLOSED LOW STAYS WELL WEST OF THE THE STATE THROUGH
SUNDAY ON THESE LATEST RUNS.
AVIATION...WILL STILL SEE A CHC OF SNOW SHOWERS THU 02Z WITH
ACCUMULATIONS AT DIA AN INCH OR LESS. AFTER 02Z SNOW CHANCES
SHOULD DIMINISH WITH ONLY A FEW FLURRIES POSSIBLE. CEILINGS AND
VISIBILITIES MAY STILL DROP DOWN TO MVFR LVLS DUE TO SNOW THRU
02Z. AFTER 02Z WILL KEEP CEILINGS AROUND 6000 FT THRU 07Z. WINDS
SHOULD BE NNE THRU THE EARLY EVENING BUT THEN BECOME LIGHT SSWLY
AFTER 03Z THRU MON MORNING. ON MON EXPECT VFR CONDITIONS WITH
LIGHT SSE WINDS BY AFTN.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM....RJK
UPDATE/AVIATION...MEIER
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1031 PM EDT SUN MAR 24 2013
.SYNOPSIS...
LOW PRESSURE IMPACTS THE REGION TO BEGIN THE WEEK. HIGH PRESSURE
THEN SLOWLY BUILDS IN FROM THE WEST THROUGH THE END OF THE WEEK
INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
TWO MAIN CHANGES THIS UPDATE. FIRST WAS TO RAISE MINIMUM TEMPERATURES A
TAD BASED ON IDEA THAT TEMPERATURES WILL NOT FALL OFF TO MUCH FROM
CURRENT READINGS BASED ON INCREASING CLOUD COVER AND INCREASING
WINDS LATE OVERNIGHT. THIS IS CONSISTENT WITH A BLEND OF 18Z
MAV/12Z MET GUIDANCE WITH 00Z NAM AND 23Z HRRR 2-METER TEMPERATURES.
SECOND ISSUE IS HOW SOON DOES PRECIPITATION MOVE IN -BASED ON
LATEST 21Z SREF/00Z NAM/18Z GFS SHOWING SLIGHT SLOWING TREND BASED
ON SLIGHTLY STRONGER RIDGE ALOFT HAVE ADJUSTED TO A DRY FORECAST
FOR OVERNIGHT.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
AN EXAMINATION OF 18Z GFS AS WELL AS QUICK LOOK AT 21Z SREF AND
00Z NAM SUGGEST PRECIPITATION LIKELY WILL GET STARTED A TAD LATER.
AS FOR AMOUNTS - 18Z GFS WAS WETTER THAN 12Z GFS WHILE 00Z NAM
DRIER THAN 18Z AND 12Z NAM. 21Z SREF SEEMS FAIRLY CONSISTENT WITH
CURRENT FORECAST. BASED ON THE INCONSISTENT MESSAGE IN THE NAM AND
GFS AND SUPPORT FOR CURRENT FORECAST IN LATEST SREF - MADE NO
ADJUSTMENTS TO FORECAST IN SHORT TERM OTHER THAN TO BLEND IN
CHANGES MADE IN TEMPERATURES AND POPS IN THE NEAR TERM.
MONDAY EXPECTED TO BE A WET AND WINDY DAY WITH A COASTAL LOW
PASSING JUST TO THE SOUTH. THIS STORM WILL BRING ABOUT A COUPLE OF
CONCERNS FOR THE REGION...IN THE FORM OF PRECIPITATION AND WINDS.
MODEL GUIDANCE CONTINUES TO COME INTO BETTER AGREEMENT WITH
TIMING...WITH SOME DIFFERENCES STILL THOUGH IN THE TOTAL QPF
AMOUNTS...ESP MIDDAY MONDAY. 12Z NAM REMAINS THE WETTEST
SOLUTION...WITH THE GFS SLIGHTLY DRIER...AND 12Z ECMWF EVEN DRIER.
HARD TO GO WITH THE NAM SOLUTION WITH THE CONSISTENCY OF THE OTHER
MODELS...SO HAVE GONE WITH MORE CONSERVATIVE AMOUNTS...BLENDING
THE WPC WITH THE GFS AND ECMWF. THIS PRODUCES THE HIGHEST AMOUNTS
ACROSS THE COASTAL REGIONS...WITH LOWER AMOUNTS TO THE NORTH AND
WEST. SURFACE TEMPS WILL LIKELY TOP OUT IN THE MID TO UPPER 30S.
GFS TENDING TO BE THE WARMER SOLUTION...PUSHING TEMPS INTO THE 40S
ALONG THE COAST BY THE AFTERNOON. HOWEVER...THINKING WE SHOULD SEE
COOLING IN THE VERTICAL COLUMN WITH THE HEAVIEST PRECIPITATION
LATE MORNING AND DURING THE AFTERNOON...WHICH WOULD KEEP TEMPS IN
THE 30S. LEANED TO NAX WET BULB TEMPS FOR TEMPS DURING THE DAY
WITH THE PRECIPITATION ONGOING...RESULTING IN MAINLY A LIGHT TO
MODERATE SNOW EVENT. HOWEVER...IF THOSE TEMPS CAN WARM A COUPLE
MORE DEGREES IN THE AFTERNOON...COULD SEE SOME RAIN MIXING WITH
THE SNOW...MAINLY ALONG THE COASTAL REGIONS. ANY PRECIPITATION
AFTER 00Z SHOULD COME BACK TO LIGHT SNOW.
THE BEST FORCING CURRENTLY LOOKS TO BE OVER THE NYC METRO REGION
AND EAST...WHERE WE COULD SEE 2 TO 3 INCHES...WITH POSSIBLE 4 TO
5 INCHES IN ISOLATED AREAS. BECAUSE OF THESE TOTALS...HAVE ISSUED
A WINTER WEATHER ADVISORY FOR NORTHEAST NJ...NYC METRO...AND LONG
ISLAND. IF THE BANDING SETS UP FURTHER TO THE NORTH DURING MONDAY
AFTERNOON...COULD SEE THE NEED OF THE ADVISORY TO BE EXPANDED.
BECAUSE OF THE SURFACE TEMPS...ANY SNOW THAT OCCURS WILL BE WET
AND HEAVY IN NATURE.
IN ADDITION TO THE SNOW...GUSTY WINDS EXPECTED MAINLY DURING THE
DAY MONDAY. DEVELOPING LOW LEVEL JET OVER THE REGION WITH WINDS
BETWEEN 35 AND 45 KTS...COMBINED WITH A TIGHT PRESSURE GRADIENT
SHOULD PRODUCE GUSTS INTO THE 35 TO 40 MPH RANGE LATE MORNING
THROUGH THE AFTERNOON. HOWEVER...LOW CONFIDENCE OF REACHING WIND
ADVISORY LEVELS AND THUS WILL NOT ISSUE ANY PRODUCTS.
THE LOW PUSHES OFF TO THE EAST MONDAY NIGHT...WITH THE PRECIPITATION
ENDING FROM WEST TO EAST AFTER MIDNIGHT THROUGH EARLY TUES
MORNING...WITH ALL PRECIPITATION EXPECTED OUT OF THE REGION BY 12Z
TUES.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
THE REGION WILL BE STUCK IN A MEAN TROUGHING PATTERN THROUGH THE
REMAINDER OF THE LONG TERM PERIOD. THIS WILL ALLOW FOR ONLY A
GRADUAL MODERATION TOWARDS SEASONABLE LEVELS BY THE WEEKEND WITH A
RATHER PERSISTENT NW FLOW. WEAK SHORTWAVES/SURFACE TROUGHS PASSING
THROUGH THE REGION WILL RESULT IN SCT/BKN INSTABILITY
CU...PARTICULARLY DURING THE DAY...WITH SCT FLURRIES/SPRINKLES.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
WEAK HIGH PRESSURE RETREATS TO THE NORTH AS A STORM SYSTEM
DEVELOPS OFF THE MID ATLANTIC COAST OVERNIGHT. THIS LOW THEN TRACKS
WELL SOUTH OF LONG ISLAND MONDAY.
VFR TONIGHT. LIGHT SNOW DEVELOPS BETWEEN 11-18Z...SOONEST CITY
TERMINALS AND LAST KGON. CONDITIONS DETERIORATE TO IFR AT
CITY/LONG ISLAND TERMINALS MID TO LATE MORNING AND CT
TERMINALS/KSWF EARLY MONDAY AFTERNOON. MODERATE SNOW FORECAST AT
CITY/LONG ISLAND TERMINALS DURING THE MONDAY AFTERNOON PUSH - LOW
PROBABILITY OF MODERATE SNOW ELSEWHERE.
SNOW ACCUMULATIONS ON RUNWAYS POSSIBLE MONDAY AFTERNOON INTO THE
EARLY EVENING WITH 2 TO 3 INCHES IN THE NYC METRO AREA AND LONG
ISLAND...AROUND 2 INCHES AT KHPN...1-2 ALONG THE CT COAST...AND UP
TO AN INCH ELSEWHERE.
LIGHT AND VARIABLE WINDS ALL TERMINALS SHOULD BECOME NE AT 4-7KT
AROUND/SHORTLY AFTER MIDNIGHT. WINDS INCREASE TO 10-15 KT DURING
THE MORNING PUSH...THEN TO 15-20G25-30KT BY MID TO LATE MORNING.
WINDS BACK TO THE NNE AND DIMINISH SLIGHTLY BY LATE
AFTERNOON/EARLY MONDAY EVENING.
.OUTLOOK FOR 00Z TUESDAY THROUGH FRIDAY...
.MONDAY NIGHT...LIGHT SNOW ENDING WITH N WINDS G20-30 KT IN THE
EVENING...THEN BECOMING VFR TOWARDS/AROUND MIDNIGHT WITH
DIMINISHING WINDS.
.TUESDAY-WEDNESDAY..VFR.
.WEDNESDAY NIGHT...VFR WITH GUSTY NW WINDS POSSIBLE.
THURSDAY-FRIDAY...VFR.
&&
.MARINE...
MINOR CHANGES MADE THIS UPDATE TO REFLECT LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE. WIND/WAVE FORECAST APPEARS ON TRACK.
DID REMOVE PRECIPITATION FROM THE FORECAST OVERNIGHT.
SUB-SCA CONDITIONS EXPECTED OVERNIGHT WITH A WEAK PRESSURE GRADIENT
OVER THE REGION. HAVE ISSUED A GALE WARNING FOR ALL WATERS DURING
THE DAY MONDAY WITH INCREASING WINDS AND SEAS LIKELY DUE TO THE
APPROACHING COASTAL LOW. WIND GUSTS UP TO 40 KTS ON THE
OCEAN...AND 35 KTS ON THE OTHER WATERS ARE EXPECTED...WITH SEAS
BETWEEN 8 AND 12 FT ON THE OCEAN AND 3 TO 6 FT ON THE SOUND. GALES
OVER THE WESTERN WATERS MAY DIMINISH BY 03Z MONDAY EVENING...AND
THE EASTERN WATERS BY 06Z.
A PERIOD OF SCA CONDITIONS THEN ARE POSSIBLE THE REST OF MONDAY
NIGHT.
WINDS SUBSIDE BELOW SCA BY TUESDAY AS THE STORM MOVES WELL
NE...WITH OCEAN SEAS GRADUALLY SUBSIDING BELOW SCA THROUGH TUE
NIGHT. A PERIOD OF MARGINAL SCA GUSTS ARE POSSIBLE DURING THE
MIDWEEK AS THE NORTHERLY FLOW TIGHTENS BETWEEN OFFSHORE LOW
PRESSURE AND HIGH PRESSURE BUILDING FROM THE WEST. WINDS SHOULD
THEN GRADUALLY SUBSIDE THROUGH THE END OF THE WEEK. &&
&&
.HYDROLOGY...
PREDICTABILITY ISSUES CONTINUE FOR THE AMOUNT OF QPF WITH A
MON/MON NIGHT STORM SYSTEM. HIGHER PROBABILITY THREAT IS FOR 1/4
TO 1/2 INCH OF LIQUID QPF...WITH A LOW THREAT OF 3/4-1 1/4 INCHES.
THIS WOULD MAINLY BE IN THE FORM OF WET SNOW...THEREFORE NO
HYDROLOGY RELATED ISSUES ARE EXPECTED.
&&
.TIDES/COASTAL FLOODING...
MINOR COASTAL FLOODING EXPECTED DURING THE TIMES OF HIGH TIDE
MONDAY EVENING...FROM AROUND 7 PM TO MIDNIGHT...WITH SURGE OF
AROUND 2 TO 2 1/2 FT. THE MAIN CONCERN IS ALONG THE SOUTH SHORE
BAYS OF LONG ISLAND...QUEENS...AND BROOKLYN AND PECONIC/GARDINERS
BAYS. EASTERLY SWELLS WILL LIKELY ENHANCE SURGE ALONG THE EASTERN
PORTIONS OF THE TWIN FORKS.
WITH WINDS EXPECTED TO TURN NNE IN THE LATE AFTERNOON/EVENING AND
THIS BEING A LATE SECOND PERIOD MARGINAL EVENT WILL HOLD OFF ON
AN ADVISORY AT THIS TIME ALONG NY HARBOR AND WESTERN LONG ISLAND
SOUND. WATER LEVELS WILL LIKELY FLIRT WITH AND LOCALLY EXCEED
MINOR COASTAL FLOOD THRESHOLDS ACROSS THIS AREA...PARTICULARLY NE
FACING COASTLINES.
ADDITIONALLY...MINOR TO MODERATE BEACH EROSION ISSUES ARE LIKELY
ALONG OCEAN BEACHES WITH 6 TO 9 FT BREAKING SURF AND AN EASTERLY
LONGSHORE CURRENT.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...WINTER WEATHER ADVISORY FROM 6 AM MONDAY TO MIDNIGHT EDT
MONDAY NIGHT FOR NYZ072>075-078>081-176>179.
COASTAL FLOOD ADVISORY FROM 6 PM MONDAY TO 2 AM EDT TUESDAY
FOR NYZ079>081.
COASTAL FLOOD ADVISORY FROM 6 PM TO 10 PM EDT MONDAY FOR
NYZ075-178-179.
NJ...WINTER WEATHER ADVISORY FROM 6 AM MONDAY TO MIDNIGHT EDT
MONDAY NIGHT FOR NJZ002-004-006-103>108.
MARINE...GALE WARNING FROM 11 AM MONDAY TO 2 AM EDT TUESDAY FOR ANZ330-
335-338-340-345-350-353-355.
&&
$$
SYNOPSIS...SEARS/NV
NEAR TERM...MALOIT
SHORT TERM...MALOIT/SEARS
LONG TERM...NV
AVIATION...MALOIT
MARINE...MALOIT/SEARS/NV
HYDROLOGY...SEARS/NV
TIDES/COASTAL FLOODING...NV
AREA FORECAST DISCUSSION
NWS JACKSONVILLE FL
420 AM EDT SAT MAR 23 2013
...HEAVY RAINFALL AND STRONG TO SEVERE STORMS POTENTIAL EXISTS TODAY
THROUGH SUNDAY...
.CURRENTLY...A WARM FRONT IS LOCATED OVER CENTRAL FL LIFTING SLOWLY
NWD. THIS WARM FRONT EXTENDS W TO NW TO A SFC LOW OVER ERN TX/LA.
LOW LEVEL FLOW JUST OFF THE SFC IS SLY PER RAP MODEL WHICH WILL AID
IN THE FRONT LIFTING UP INTO OUR AREA LATER TODAY. OUR AIRMASS
REMAINS RELATIVELY DRY AT THE MOMENT WITH PWATS GENERALLY NEAR 1
INCH OR LESS...THOUGH THE MOIST AIRMASS OVER CENTRAL FL WITH PWATS
IN EXCESS OF 1.5 INCHES WILL BE HEADING IN OUR DIRECTION NEXT 12-18
HRS. SFC WIND FIELD IS NE TO E OVER LAND BUT A TROUGH IS NOTED FROM
PUTNAM COUNTY NEWD INTO THE JAX COASTAL WATERS. THE LOW LEVEL
CONVERGENCE WILL LIKELY AID IN SOME SHOWER DEVELOPMENT OVER THE NEXT
FEW HRS OVER THE COASTAL WATERS. TEMPS RANGE FROM UPPER 40S N ZONES
TO NEAR 60 ACROSS THE SOUTH AS MID AND HIGH CLOUDS CONTINUE TO
INCREASE.
.SHORT TERM...
SUMMARY...FAIRLY COMPLICATED FCST NEXT 2 DAYS WITH WARM FRONT
LIFTING NWD THROUGH THE AREA TODAY...BRIEFLY STALLING NEAR THE FL/GA
STATE LINE THIS EVENING...THEN PUSH BACK NWD LATE TONIGHT. A
PREFRONTAL TROUGH/SQUALL LINE DEVELOPS JUST W OF THE AREA LATE
TONIGHT AND MOVES INTO OUR AREA SUNDAY...FOLLOWED BY A COLD FRONTAL
PASSAGE SUNDAY EVENING THROUGH LATE SUN NIGHT. MEDIUM CONFIDENCE ON
SEVERE STORMS TODAY THROUGH SUNDAY WITH HEAVY RAINFALL ALSO VERY
POSSIBLE...THUS HAVE INCLUDED THIS RAINFALL AND SEVERE STORM
WORDING IN TODAY-TONIGHTS WX GRIDS.
TODAY...THE W-E WARM FRONT WILL INITIALLY BEGIN NEAR MARION COUNTY
AND LIFT NWD TO SE GA IN THE AFTN AND THEN BEGIN TO STALL IN THE
EVENING HRS AS NELY WINDS INCREASE N OF FRONT DUE TO COOL AIR WEDGE
OVER THE CAROLINAS AND ERN GA. AS THE AREA GETS MORE INTO THE WARM
SECTOR TODAY INSTABILITY WILL INCREASE AND POTENTIAL EXISTS FOR
STRONG TO SEVERE STORMS...WITH ENOUGH 0-3 KM HELICITY (AROUND THE
150-250 RANGE) ALSO FOR ROTATING STORMS/TORNADIC CELLS. WE ALSO
EXPECT HEAVY RAINFALL TO BECOME MORE LIKELY IN THE AFTN AND EVENING
HOURS AS UPPER LEVEL WINDS BECOME MORE FAVORABLE FOR DIFFLUENCE AND
THE FRONT BRIEFLY STALLS. THIS HEAVY RAINFALL MORE OR LESS STRADDLES
FL/GA STATE LINE ABOUT 60 MILES EITHER SIDE OF LINE. THOUGH ABUNDANT
CLOUD COVER WILL DEVELOP...HIGHS SHOULD STILL MANAGE TO REACH THE
UPPER 60S TO THE MID AND UPPER 70S THANKS TO SLY FLOW AND WARM
ADVECTION.
TONIGHT...THE CORRIDOR OF HEAVY RAINFALL WILL BEGIN TO SHIFT NEWD AS
SFC LOW W OF THE AREA MOVES NEWD AND SHORTWAVE ENERGY MOVES NE OF
THE AREA. POPS SHOULD DECREASE FROM S TO N OVERNIGHT BUT STILL
REMAIN UP INTO THE LIKELY TO CATEGORY RANGE MAINLY IN SE GA. SOME FOG
WILL BE POSSIBLE OVER THE NEARSHORE COASTAL WATERS/NEAR THE COAST
THANKS TO HIGH DEWPOINTS BUT DURATION AND CONFIDENCE PRECLUDES FROM
INCLUDING ANY AT THIS TIME. SEVERE WX POTENTIAL REMAINS N OF I-10.
SUNDAY...BOTH NAM AND GFS SHOW WARM FRONT N OF THE AREA 12Z SUN
WHILE A PREFRONTAL SQUALL LINE SHIFTS EWD THROUGH THE AREA AND THEN
OFF THE COAST IN THE AFTN. POTENTIAL STILL WILL EXIST FOR STRONG TO
SEVERE STORMS WITH DAMAGING WINDS AND PERHAPS A CHANCE FOR AN
ISOLATED TORNADO ALONG/AHEAD OF SQUALL LINE. MORE WLY FLOW ALOFT
WILL ALLOW FOR AIRMASS TO DRY OUT IN AFTN BEFORE ACTUAL COLD FRONT
ARRIVES SUN EVENING. AS SUCH...POPS WILL DECREASE IN THE AFTN BUT
POTENTIAL FOR STORMS REMAINS IN THE AFTN DUE TO LOW LEVEL MOISTURE
STILL AVAILABLE (DEWPOINTS THE MID AND UPPER 60S). SHOULD ALSO BE
WINDY WITH STRONG GUSTY WINDS POSSIBLE AT ANY TIME (EVEN OUTSIDE
CONVECTIVE AREAS) GIVEN THE 850 MB WINDS AT 40-50 KT.
SUN NIGHT...SWLY WINDS AT LEAST NEAR 10-15 MPH BEGIN THE EVENING
AHEAD OF THE FRONT...THEN THE FRONT PRESSES SEWD DURING THE
OVERNIGHT WITH WINDS TURNING ONLY W TO WNW IN WAKE OF FRONT. DUE TO
LINGERING LOW LEVEL MOISTURE...HAVE KEPT IN SOME LOW POPS IN FOR THE
EVENING ASSOCD WITH FROPA BUT MOST OF THE MOISTURE WILL HAVE MOVED
OUT OF THE AREA. LEANED TOWARD SLIGHTLY WARMER LOWS MAINLY IN THE
UPPER 40S AND LOWER TO MID 50S GIVEN WINDS STAYING UP AROUND 10-15
MPH AND GUSTY.
MON-MON NIGHT...DEEP WNW TO NW FLOW WILL MAINTAIN A DRY FCST DURING
THIS PERIOD WITH MUCH COOLER TEMPS. HIGHS ON MON IN THE 60S AND LOWS
MON NIGHT INTO THE UPPER 30S AND LOWER TO MID 40S. WILL NEED TO
MONITOR WINDS ON MON WITH DEEP LAYER MIXING AND STRONG WINDS AT 850
MB ENABLING GUSTS AROUND 30-35 MPH POSSIBLE.
.LONG TERM...TUE-FRI.
ESSENTIALLY LITTLE CHANGE IN THINKING DURING THIS PERIOD. SFC HIGH
PRESSURE RIDGE W OF THE AREA WILL MAINTAIN A DRY AND STABLE AIRMASS
AND DEEP NORTHWESTERLY FLOW. TEMPS WILL BE COOLER THAN NORMAL.
AS HIGH MOVES CLOSER TO THE REGION...LOWS WILL LIKELY REACH INTO THE
MID AND UPPER 30S ON WED AND THU MORNINGS. TEMPERATURES WILL BEGIN
TO MODERATE ON FRI...BUT THE DRY WEATHER IS EXPECTED TO CONTINUE.
&&
.AVIATION...
CEILINGS WILL LOWER TO MVFR THIS MORNING AT ALL AREA TERMINALS AS
A WARM FRONT LIFTS NORTH ACROSS THE AREA. SHOWERS AND THUNDERSTORMS
WILL INCREASE IN COVERAGE THIS AFTERNOON...AND RAIN IS EXPECTED
AT ALL TERMINALS...WITH RAIN HEAVY AT TIMES THIS AFTERNOON AND
EVENING. IFR CONDITIONS AND GUSTY WINDS CAN BE EXPECTED IN THE
HEAVIER ACTIVITY. RAIN CHANCES WILL BECOME MUCH LOWER AT GNV THIS
EVENING...BUT RAIN CHANCES WILL REMAIN HIGH FOR THE REMAINING
TERMINALS. SHOWERS AND THUNDERSTORMS ALONG A STALLED FRONTAL
BOUNDARY ARE EXPECTED TO CONTINUE THROUGH THE EVENING HOURS AT
THE THREE JACKSONVILLE TERMINALS AND THROUGH MUCH OF THE NIGHT AT
SSI.
&&
.MARINE...
WINDS WILL CONTINUE TO VEER TO THE SOUTH TODAY AS A WARM FRONT
LIFTS NORTH THROUGH THE AREA. THE FRONT WILL SLIP BACK TO THE
SOUTH AND STALL ACROSS THE GEORGIA WATERS LATE THIS AFTERNOON AND
EVENING...BEFORE LIFTING BACK TO THE NORTH OF THE AREA EARLY
SUNDAY MORNING. A COLD FRONT WILL FINALLY SWEEP ACROSS THE WATERS
SUNDAY NIGHT. EXPECT WIDESPREAD SHOWERS AND NUMEROUS THUNDERSTORMS
TODAY AND TOMORROW. SCA CONDITIONS WILL DEVELOP JUST AHEAD OF AND
IN THE WAKE OF THE COLD FRONT FROM SUNDAY MORNING THROUGH EARLY
NEXT WEEK. WINDS AND SEAS WILL SUBSIDE BY WEDNESDAY AS HIGH
PRESSURE BUILDS OVER THE REGION.
RIP CURRENTS: LOW RISK THROUGH THE WEEKEND.
&&
.HYDROLOGY...STORM TOTAL RAINFALL AMOUNTS FROM TODAY THROUGH SUN
EVENING...RELATIVELY WIDESPREAD AT 1-2 INCHES ANTICIPATED. AREAS
FROM NEAR THE I-10 CORRIDOR NWD TO ABOUT ALMA GA COULD SEE 2-4
INCHES.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 71 61 81 47 / 90 90 80 20
SSI 70 62 76 49 / 90 90 70 20
JAX 74 64 81 50 / 80 80 70 20
SGJ 74 66 80 53 / 80 70 70 20
GNV 76 66 83 51 / 90 60 80 30
OCF 79 66 82 53 / 80 50 70 40
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GA...NONE.
AM...NONE.
&&
$$
SHASHY/SHULER/
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1007 PM EDT SUN MAR 24 2013
.SYNOPSIS...
SKIES WILL BEGIN TO CLEAR LATE TONIGHT BEHIND A COLD FRONT. VERY
WINDY CONDITIONS EXPECTED FOR MONDAY. FAIR AND BREEZY TUESDAY...AS
HIGH PRESSURE REMAINS TO OUR WEST. THE HIGH PRESSURE CENTER WILL
BUILD INTO OUR REGION MID TO LATE WEEK.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
COLD FRONT PUSHING THROUGH CENTRAL GEORGIA AND THE UPSTATE OF
SOUTH CAROLINA AT THIS TIME AND WILL CONTINUE TO RUSH EASTWARD
LATE THIS EVENING. MOST OF THE PRECIPITATION HAS DISSIPATED AS IT
ENCOUNTERS A MUCH MORE STABLE AIRMASS WITH THE WEDGE HOLDING
STRONG BUT THERE ARE A FEW SHOWERS HOLDING TOGETHER BETWEEN THE
I-85 AND I-77 CORRIDORS. WILL HOLD ON TO SLIGHT CHANCE POPS FOR A
FEW MORE HOURS AS THE FRONT PASSES THEN DRY THINGS OUT. ALSO
LOWERED OVERNIGHT LOWS AS THE FRONT IS PUSHING EAST A BIT FASTER
THAN EXPECTED AND MORE COLD ADVECTION SHOULD LOWER TEMPS A BIT
MORE THAN PREVIOUSLY THOUGHT.
THE PRESSURE GRADIENT WILL BE TIGHTENING AND THE WIND FIELDS WILL
BEGIN TO INCREASE OVER THE REGION AFTER MIDNIGHT. THE INCREASE IN
WINDS...ALONG WITH SOME DRIER AIR ALOFT...SHOULD HELP TO ERODE THE
LOW LEVEL WEDGE OUT LATE TONIGHT. NO ISSUES WITH FROST TONIGHT
WITH WINDS REMAINING UP.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
UPPER ENERGY TO SHIFT TO THE NE U.S. COAST MONDAY...WHILE INLAND
LOW WEAKENS AND COASTAL LOW INTENSIFIES. TIGHT PRESSURE GRADIENT
OVER OUR REGION TO LEAD TO BREEZY TO WINDY CONDITIONS MONDAY. PLAN
TO ISSUE A WIND ADVISORY...BEGINNING AT 8 AM MONDAY MORNING AND
RUNNING UNTIL 8 PM MONDAY EVENING. UPPER TROUGH AXIS TO COME
THROUGH TUESDAY. PRESSURE GRADIENT REMAINING TIGHT TUESDAY...WITH
LOW WELL OFF TO OUR NE AND STRONG HIGH PRESSURE TO OUR WEST. IT
APPEARS BREEZY CONDITIONS WILL CONTINUE TUESDAY...BUT NOT AS WINDY
AS MONDAY.
TEMPERATURES WILL REMAIN A FEW DEGREES BELOW NORMAL WITH HIGHS IN
THE LOWER TO MIDDLE 50S AND LOWS IN THE LOWER TO MIDDLE 30S. FREEZE
WARNINGS MAY BE REQUIRED MONDAY NIGHT AND/OR TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
NO SIGNIFICANT CHANGES MADE TO THE ONGOING FORECAST. LEANED TOWARDS
HPC SOLUTION. OUR REGION TO REMAIN IN A DRY COOL NW FLOW ALOFT AS
UPPER TROUGHINESS REMAINS ALONG THE U.S. EAST COAST. SURFACE HIGH
PRESSURE WILL BUILD INTO THE REGION. SOME UNCERTAINTY LATE IN THE
FORECAST PERIOD WITH REGARD TO TIMING OF THE NEXT WEATHER SYSTEM.
INSUFFICIENT CONFIDENCE TO INTRODUCE POPS AT THIS TIME. TEMPERATURES
WILL GRADUALLY MODERATE THROUGH THE PERIOD...BUT WILL REMAIN JUST A
LITTLE BELOW NORMAL.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
A WEDGE OF COOL AND MOIST AIR WITH MAINLY IFR CONDITIONS WILL
CONTINUE UNTIL FRONTAL PASSAGE LATE TONIGHT. EXPECT IMPROVEMENT
WILL BEGIN DURING THE 06Z TO 08Z TIME FRAME AS DRYING OCCURS
BEHIND THE FRONT. THE GFS LAMP...SREF GUIDANCE AND HRRR WERE IN
CLOSE AGREEMENT WITH THIS TIMING. IT WILL BECOME BREEZY BEHIND THE
FRONT ESPECIALLY DURING THE DAY MONDAY WHEN STRONG MIXING OCCURS.
THE NAM BUFKIT MOMENTUM TRANSFER TOOL INDICATES NEAR 35 KNOTS.
EXTENDED AVIATION OUTLOOK...NO CEILING OR VISIBILITY RESTRICTIONS
EXPECTED MONDAY NIGHT THROUGH FRIDAY...BUT BREEZY CONDITIONS WILL
OCCUR TUESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...WIND ADVISORY FROM 8 AM TO 8 PM EDT MONDAY FOR SCZ015-016-018-
020>022-025>031-035>038-041.
GA...WIND ADVISORY FROM 8 AM TO 8 PM EDT MONDAY FOR GAZ040-063>065-
077.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
754 PM EDT SUN MAR 24 2013
.SYNOPSIS...
SKIES WILL BEGIN TO CLEAR LATE TONIGHT BEHIND A COLD FRONT. VERY
WINDY CONDITIONS EXPECTED FOR MONDAY. FAIR AND BREEZY TUESDAY...AS
HIGH PRESSURE REMAINS TO OUR WEST. THE HIGH PRESSURE CENTER WILL
BUILD INTO OUR REGION MID TO LATE WEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
UPPER DISTURBANCE MOVING ACROSS TENNESSEE VALLEY AT THIS TIME
DRIVING A COLD FRONT TOWARDS THE REGION. WEDGE CONDITIONS HOLDING
STRONG WITH NORTHERLY FLOW AND LOW CLOUDS WITH TEMPS IN THE 40S.
HAVE UPDATED FORECAST TO DROP POPS FOR A FEW HOURS UNTIL COLD
FRONT PUSHING ACROSS TN/GA ARRIVES FROM THE WEST. A BROKEN LINE OF
SHOWERS SHOULD REACH WESTERN COUNTIES AROUND 02Z AND PUSH ACROSS
THE FORECAST AREA EXITING THE EASTERN COUNTIES 05Z-06Z. MAY NEED
TO INCREASE POPS A BIT HIGHER AND WILL EVALUATE THAT FOR LATE
EVENING UPDATE. DRIER AIR WILL WORK IN BEHIND THE FRONT AS HIGH
PRESSURE BUILDS INTO THE REGION. THE PRESSURE GRADIENT WILL BE
TIGHTENING AND THE WIND FIELDS WILL BEGIN TO INCREASE OVER THE
REGION AFTER MIDNIGHT. THE INCREASE IN WINDS...ALONG WITH SOME
DRIER AIR ALOFT...SHOULD HELP TO ERODE THE LOW LEVEL WEDGE OUT
LATE TONIGHT. COLDER AIR WILL BE ENTERING THE REGION BEHIND THE
LOW...WHICH WILL ALLOW OVERNIGHT TEMPERATURES TO FALL INTO THE 30S
ACROSS THE MAJORITY OF THE REGION. NO ISSUES WITH FROST TONIGHT
WITH WINDS REMAINING UP.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
UPPER ENERGY TO SHIFT TO THE NE U.S. COAST MONDAY...WHILE INLAND
LOW WEAKENS AND COASTAL LOW INTENSIFIES. TIGHT PRESSURE GRADIENT
OVER OUR REGION TO LEAD TO BREEZY TO WINDY CONDITIONS MONDAY. PLAN
TO ISSUE A WIND ADVISORY...BEGINNING AT 8 AM MONDAY MORNING AND
RUNNING UNTIL 8 PM MONDAY EVENING. UPPER TROUGH AXIS TO COME
THROUGH TUESDAY. PRESSURE GRADIENT REMAINING TIGHT TUESDAY...WITH
LOW WELL OFF TO OUR NE AND STRONG HIGH PRESSURE TO OUR WEST. IT
APPEARS BREEZY CONDITIONS WILL CONTINUE TUESDAY...BUT NOT AS WINDY
AS MONDAY.
TEMPERATURES WILL REMAIN A FEW DEGREES BELOW NORMAL WITH HIGHS IN
THE LOWER TO MIDDLE 50S AND LOWS IN THE LOWER TO MIDDLE 30S. FREEZE
WARNINGS MAY BE REQUIRED MONDAY NIGHT AND/OR TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
NO SIGNIFICANT CHANGES MADE TO THE ONGOING FORECAST. LEANED TOWARDS
HPC SOLUTION. OUR REGION TO REMAIN IN A DRY COOL NW FLOW ALOFT AS
UPPER TROUGHINESS REMAINS ALONG THE U.S. EAST COAST. SURFACE HIGH
PRESSURE WILL BUILD INTO THE REGION. SOME UNCERTAINTY LATE IN THE
FORECAST PERIOD WITH REGARD TO TIMING OF THE NEXT WEATHER SYSTEM.
INSUFFICIENT CONFIDENCE TO INTRODUCE POPS AT THIS TIME. TEMPERATURES
WILL GRADUALLY MODERATE THROUGH THE PERIOD...BUT WILL REMAIN JUST A
LITTLE BELOW NORMAL.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
A WEDGE OF COOL AND MOIST AIR WITH MAINLY IFR CONDITIONS WILL
CONTINUE UNTIL FRONTAL PASSAGE LATE TONIGHT. EXPECT IMPROVEMENT
WILL BEGIN DURING THE 06Z TO 08Z TIME FRAME AS DRYING OCCURS
BEHIND THE FRONT. THE GFS LAMP...SREF GUIDANCE AND HRRR WERE IN
CLOSE AGREEMENT WITH THIS TIMING. IT WILL BECOME BREEZY BEHIND THE
FRONT ESPECIALLY DURING THE DAY MONDAY WHEN STRONG MIXING OCCURS.
THE NAM BUFKIT MOMENTUM TRANSFER TOOL INDICATES NEAR 35 KNOTS.
EXTENDED AVIATION OUTLOOK...NO CEILING OR VISIBILITY RESTRICTIONS
EXPECTED MONDAY NIGHT THROUGH FRIDAY...BUT BREEZY CONDITIONS WILL
OCCUR TUESDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...WIND ADVISORY FROM 8 AM TO 8 PM EDT MONDAY FOR SCZ015-016-018-
020>022-025>031-035>038-041.
GA...WIND ADVISORY FROM 8 AM TO 8 PM EDT MONDAY FOR GAZ040-063>065-
077.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1222 PM CDT SAT MAR 23 2013
.DISCUSSION...
ISSUED 1000 AM CDT SAT MAR 23 2013
LARGE AREA OF CLOUDINESS OVER CENTRAL ILLINOIS HAS BEEN SHOWING
SOME SIGNS OF EROSION OVER THE LAST HOUR OR SO...BUT ANOTHER LARGE
AREA OF MID AND HIGH CLOUDS WAS APPROACHING FROM THE WEST...SO THE
NET FORECAST OF PARTLY SUNNY CONDITIONS SHOULD STILL HOLD. HAVE
MADE SOME TWEAKS TO THE HOURLY TEMPERATURE TRENDS SINCE OVERNIGHT
LOWS WERE SEVERAL DEGREES HIGHER THAN EXPECTED...BUT HAVE MADE
LITTLE CHANGE TO THE OVERALL HIGHS FOR TODAY. HAVE SENT THE GRID
UPDATES...BUT NO CHANGES NEEDED TO THE WORDED FORECASTS.
EARLY LOOK AT THE 12Z NAM AND THE LATEST RAP-13 STILL SUPPORTIVE
OF PRECIPITATION BEGINNING TO MOVE INTO THE SOUTHWEST CWA LATE IN
THE EVENING. RAP MODEL WOULD SUGGEST SOME RAIN/SNOW MIX INITIALLY
WHILE THE NAM IS MORE SUPPORTIVE OF ALL SNOW. LATEST NAM CONTINUES
TO INDICATE A COUPLE PERIODS OF GREATER INTEREST...ONE BEFORE
SUNRISE WITH THE INITIAL SURGE AND THE OTHER FROM LATE MORNING
THROUGH MOST OF THE EVENING WITH THE UPPER LOW. NAM CONTINUES TO
FOCUS ALONG AND SOUTH OF THE I-72 CORRIDOR WITH THE HEAVIEST SNOW.
NO CHANGES WILL BE MADE TO THE WATCH YET...AS WE AWAIT THE
REMAINING MODEL GUIDANCE THIS MORNING.
GEELHART
&&
.AVIATION...
ISSUED 1220 PM CDT SAT MAR 23 2013
MAIN FOCUS IS ON THE PERIOD BEGINNING AFTER 03Z...AS PRECIPITATION
BEGINS TO SPREAD NORTHEAST INTO CENTRAL ILLINOIS WITH A MAJOR
LATE WINTER STORM. THINK KSPI WILL BE THE ONLY AREA TAF SITE TO
SEE PRECIP BEFORE 06Z...BUT IT WILL SPREAD OVER THE REST OF
CENTRAL ILLINOIS FROM 06-09Z. CONDITIONS LIKELY TO QUICKLY DROP
INTO MVFR CATEGORY AS THE SNOW BEGINS AND THEN INTO IFR RANGE
WITHIN A COUPLE HOURS. CURRENTLY LOOKS LIKE THERE WILL BE ABOUT A
2 TO 4 HOUR WINDOW AT MOST SITES BETWEEN 12-16Z WITH LITTLE
PRECIPITATION...ALTHOUGH CEILINGS STILL EXPECTED TO REMAIN BELOW
2000 FEET DURING THIS WINDOW. MORE WIDESPREAD IMPACTS EXPECTED
AFTER 18Z WITH POTENTIAL VLIFR CEILINGS/VISIBILITIES IN MODERATE
TO HEAVY SNOW.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 311 AM CDT SAT MAR 23 2013
FORECAST ISSUE TODAY IS THE WINTER STORM TO EFFECT REGION NEXT FEW
DAYS.
SHORT TERM...TODAY THROUGH MONDAY NIGHT.
00Z UPPER AIR AND PROFILER DATA DEPICTS UPPER LOW AREA OVER THE
MT-ID-WY REGION WITH NEXT JET MAX DIVING SOUTHEAST INTO OR-NV.
850-925 MB DATA SHOWS MOISTURE OVER WESTERN GULF AREA PRIMED
ALREADY PRIMED TO MOVE NORTH LATER TODAY.
NEW MODEL GUIDANCE CONSISTENT IN STRENGTHENING OF UPPER LOW CENTER
AND MOVEMENT TO CENTRAL PLAINS BY SATURDAY EVENING. IN
RESPONSE...MAJOR SNOW AREA DEVELOPS OVER CENTRAL PLAINS NORTH OF
LOW-INVERTED TROF OVER THE SOUTHERN MS VALLEY REGION. THE UPPER
LOW TRACKS ACROSS SOUTHERN MO AND INTO SOUTHERN IL...AS SURFACE
LOW DEEPENS AND BECOMES VERTICALLY STACKED BY 24/18Z OVER SOUTHERN
IL BORDER...THEN TRACKING EASTWARD OVER OH RIVER. THE RESULT IS
AREA OF HEAVY SNOW OVER MUCH OF CENTRAL IL...BEGINNING AROUND
24/06Z...WITH HEAVIEST THROUGH DAY SUNDAY AND LINGERING IN THE
EAST SECTIONS THROUGH MUCH OF SUNDAY NIGHT...UNTIL THE DEFORMATION
ZONE OF THE STACKED LOW CENTER MOVES ENOUGH TO THE EAST. NAM AND
GFS PRETTY SIMILAR IN STORM TRACK...BUT NEW MODELS A LITTLE LESS
ON STRENGTHEN OF THE LIFT AHEAD OF SYSTEM SATURDAY NIGHT. FOR THAT
REASON...FORECAST AMOUNTS LOWER THEN AND SO WILL STAY WITH WATCH.
MAIN HEAVY SNOW TO BE WITH APPROACH AND DEEPENING OF THE LOW
THROUGH DAY SUNDAY.
MAIN SNOW BAND OVER CENTRAL SECTIONS...6 INCH AREA SOUTH OF EL
PASO TO FAIRVIEW LINE...AND NORTH OF A EFFINGHAM TO MARSHALL
LINE. MAX 7-8 INCH AREA POSSIBLE CENTERED ON TAYLORVILLE TO
CHRISMAN.
LONG TERM...TUESDAY THROUGH FRIDAY.
ONCE THIS SYSTEM MOVES THROUGH...QUIET CONDITIONS ARE THE RULE FOR
MOST OF THE WEEK. HOWEVER BY THE END OF THE PERIOD...ON
FRIDAY...THE UPPER LEVEL PATTERN APPEARS TO BE SHIFTING WITH THE
UPPER RIDGE AXIS MOVING TO A POSITION OVER THE MIDWEST. PCPN MAY
BECOME A POSSIBILITY LATE IN THE WEEK...HOWEVER THE MODELS APPEAR
TO DIFFER ON THE SOLUTION NOW. SO DID NOT INTRODUCE AND PCPN AT
THIS TIME FOR LATE IN THE WEEK.
GOETSCH
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT
FOR ILZ027>029-036-037-040>042-047>054-061-066-071.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING FOR
ILZ030-031-038-043>046-055>057-062-063-067-068-072-073.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1003 AM CDT SAT MAR 23 2013
.DISCUSSION...
ISSUED 1000 AM CDT SAT MAR 23 2013
LARGE AREA OF CLOUDINESS OVER CENTRAL ILLINOIS HAS BEEN SHOWING
SOME SIGNS OF EROSION OVER THE LAST HOUR OR SO...BUT ANOTHER LARGE
AREA OF MID AND HIGH CLOUDS WAS APPROACHING FROM THE WEST...SO THE
NET FORECAST OF PARTLY SUNNY CONDITIONS SHOULD STILL HOLD. HAVE
MADE SOME TWEAKS TO THE HOURLY TEMPERATURE TRENDS SINCE OVERNIGHT
LOWS WERE SEVERAL DEGREES HIGHER THAN EXPECTED...BUT HAVE MADE
LITTLE CHANGE TO THE OVERALL HIGHS FOR TODAY. HAVE SENT THE GRID
UPDATES...BUT NO CHANGES NEEDED TO THE WORDED FORECASTS.
EARLY LOOK AT THE 12Z NAM AND THE LATEST RAP-13 STILL SUPPORTIVE
OF PRECIPITATION BEGINNING TO MOVE INTO THE SOUTHWEST CWA LATE IN
THE EVENING. RAP MODEL WOULD SUGGEST SOME RAIN/SNOW MIX INITIALLY
WHILE THE NAM IS MORE SUPPORTIVE OF ALL SNOW. LATEST NAM CONTINUES
TO INDICATE A COUPLE PERIODS OF GREATER INTEREST...ONE BEFORE
SUNRISE WITH THE INITIAL SURGE AND THE OTHER FROM LATE MORNING
THROUGH MOST OF THE EVENING WITH THE UPPER LOW. NAM CONTINUES TO
FOCUS ALONG AND SOUTH OF THE I-72 CORRIDOR WITH THE HEAVIEST SNOW.
NO CHANGES WILL BE MADE TO THE WATCH YET...AS WE AWAIT THE
REMAINING MODEL GUIDANCE THIS MORNING.
GEELHART
&&
.AVIATION...
ISSUED 659 AM CDT SAT MAR 23 2013
VFR CONDITIONS SHOULD CONTINUE THROUGH THIS EVENING ACROSS THE
CENTRAL IL TERMINAL AIRPORTS...THEN DETERIORATE TO IFR TO MVFR
CONDITIONS DURING OVERNIGHT WITH CEILINGS/VSBYS LOWERING DUE TO
LIGHT TO MODERATE SNOW SPREADING NE ACROSS AREA. BROKEN TO
OVERCAST CLOUDS FROM 5-8K FT TO BREAK UP DURING THE MORNING AND
HAPPEN BY MID MORNING AT PIA AND BMI AND LATE MORNING OR MIDDAY AT
SPI AND DEC. CHANCES OF FLURRIES EARLY THIS MORNING SHOULD STAY NE
OF BMI AND CMI. BROKEN TO MID LEVEL CLOUDS SPREAD BACK NE ACROSS
CENTRAL IL BETWEEN 22Z-01Z. 1001 MB LOW PRESSURE ORGANIZING NEAR
THE TX/NM BORDER TO EJECT NE INTO WEST TN BY 12Z/7 AM SUNDAY.
WIDESPREAD LIGHT TO MODERATE SNOW TO SPREAD NE ACROSS CENTRAL IL
AFTER 06Z/1 AM TONIGHT...REACHING SPI FIRST AND I-74 LAST...WITH
CEILINGS LOWERING TO 7-15K FT AND VSBYS LOWERING TO 3/4-1.5 MILES
LATE TONIGHT. NE WINDS 5-10 KTS TODAY TO INCREASE TO 12-16 KTS
OVERNIGHT WITH GUSTS 18-23 KTS LATE TONIGHT AS LOW PRESSURE GETS
CLOSER TO CENTRAL IL.
07
&&
.PREV DISCUSSION...
ISSUED 311 AM CDT SAT MAR 23 2013
FORECAST ISSUE TODAY IS THE WINTER STORM TO EFFECT REGION NEXT FEW
DAYS.
SHORT TERM...TODAY THROUGH MONDAY NIGHT.
00Z UPPER AIR AND PROFILER DATA DEPICTS UPPER LOW AREA OVER THE
MT-ID-WY REGION WITH NEXT JET MAX DIVING SOUTHEAST INTO OR-NV.
850-925 MB DATA SHOWS MOISTURE OVER WESTERN GULF AREA PRIMED
ALREADY PRIMED TO MOVE NORTH LATER TODAY.
NEW MODEL GUIDANCE CONSISTENT IN STRENGTHENING OF UPPER LOW CENTER
AND MOVEMENT TO CENTRAL PLAINS BY SATURDAY EVENING. IN
RESPONSE...MAJOR SNOW AREA DEVELOPS OVER CENTRAL PLAINS NORTH OF
LOW-INVERTED TROF OVER THE SOUTHERN MS VALLEY REGION. THE UPPER
LOW TRACKS ACROSS SOUTHERN MO AND INTO SOUTHERN IL...AS SURFACE
LOW DEEPENS AND BECOMES VERTICALLY STACKED BY 24/18Z OVER SOUTHERN
IL BORDER...THEN TRACKING EASTWARD OVER OH RIVER. THE RESULT IS
AREA OF HEAVY SNOW OVER MUCH OF CENTRAL IL...BEGINNING AROUND
24/06Z...WITH HEAVIEST THROUGH DAY SUNDAY AND LINGERING IN THE
EAST SECTIONS THROUGH MUCH OF SUNDAY NIGHT...UNTIL THE DEFORMATION
ZONE OF THE STACKED LOW CENTER MOVES ENOUGH TO THE EAST. NAM AND
GFS PRETTY SIMILAR IN STORM TRACK...BUT NEW MODELS A LITTLE LESS
ON STRENGTHEN OF THE LIFT AHEAD OF SYSTEM SATURDAY NIGHT. FOR THAT
REASON...FORECAST AMOUNTS LOWER THEN AND SO WILL STAY WITH WATCH.
MAIN HEAVY SNOW TO BE WITH APPROACH AND DEEPENING OF THE LOW
THROUGH DAY SUNDAY.
MAIN SNOW BAND OVER CENTRAL SECTIONS...6 INCH AREA SOUTH OF EL
PASO TO FAIRVIEW LINE...AND NORTH OF A EFFINGHAM TO MARSHALL
LINE. MAX 7-8 INCH AREA POSSIBLE CENTERED ON TAYLORVILLE TO
CHRISMAN.
LONG TERM...TUESDAY THROUGH FRIDAY.
ONCE THIS SYSTEM MOVES THROUGH...QUIET CONDITIONS ARE THE RULE FOR
MOST OF THE WEEK. HOWEVER BY THE END OF THE PERIOD...ON
FRIDAY...THE UPPER LEVEL PATTERN APPEARS TO BE SHIFTING WITH THE
UPPER RIDGE AXIS MOVING TO A POSITION OVER THE MIDWEST. PCPN MAY
BECOME A POSSIBILITY LATE IN THE WEEK...HOWEVER THE MODELS APPEAR
TO DIFFER ON THE SOLUTION NOW. SO DID NOT INTRODUCE AND PCPN AT
THIS TIME FOR LATE IN THE WEEK.
GOETSCH
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE SUNDAY NIGHT
FOR ILZ027>029-036-037-040>042-047>054-061-066-071.
WINTER STORM WATCH FROM LATE TONIGHT THROUGH MONDAY MORNING FOR
ILZ030-031-038-043>046-055>057-062-063-067-068-072-073.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
928 PM EDT SUN MAR 24 2013
.UPDATE...
A VIGOROUS UPPER LEVEL TROUGH WILL CONTINUE TO SHIFT EAST ACROSS
THE OHIO RIVER VALLEY TONIGHT WITH 2330Z WATER VAPOR IMAGERY
PUTTING THE CENTER OF THE UPPER LEVEL CYCLONIC CIRCULATION ACROSS
SOUTHEAST ILLINOIS. IMPRESSIVE UPPER LEVEL DYNAMICS IN PLAY THIS
EVENING IN HIGHLY DIFFLUENT FLOW PATTERN ACROSS NORTHERN
INDIANA/NORTHWEST OHIO. AS THE UPPER LOW SHIFTS
EASTWARD...DEFORMATION BAND SHOULD PIVOT ACROSS SOUTHERN PORTIONS
OF THE FORECAST AREA WITH SEVERAL HOURS OF MODERATE TO HEAVY SNOW
EXPECTED LATE EVENING INTO THE EARLY PORTIONS OF THE OVERNIGHT
HOURS. A STRONG VORT MAX PER WATER VAPOR IMAGERY/RAP
INITIALIZATION ACROSS FAR SOUTHERN INDIANA SHOULD WRAP INTO
SOUTHERN PORTIONS OF THE AREA VIA PARENT UPPER CYCLONIC
CIRCULATION TOWARD 06Z...BUT LIKELY IN A WEAKENING STATE AS IT
ENCOUNTERS STRONGER UPPER LEVEL DEFORMATION FLOW. NAM/GFS
TIME/HEIGHT SECTIONS STILL INDICATING STRONGEST UVM IN THE 00Z-06Z
TIMEFRAME THIS EVENING...WITH AN INCREASINGLY FAVORABLE OVERLAP
TOWARD 03Z OF VERTICAL MOTION AND RELATIVELY DEEP DGZ BETWEEN
750-550 HPA. ELEVATED WEAK STATIC STABILITY ALSO SHOULD MAXIMIZE
RESPONSE FROM FRONTOGENETIC/DPVA FORCING LATE THIS EVENING INTO
EARLY PORTIONS OF OVERNIGHT. ALREADY A FEW REPORTS EARLIER THIS
AFTERNOON/EVENING JUST SOUTH AND SOUTHWEST OF THE FORECAST AREA OF
1 TO 2 INCH PER HOUR SNOWFALL RATES.
OF CONCERN AS DEFORMATION BAND PIVOTS OVERNIGHT...LOW LEVEL
FRONTOGENETIC FORCING MAY REMAIN ANCHORED ACROSS WESTERN PORTIONS
OF THE AREA THAT COULD ACT TO ENHANCE SNOW AMOUNTS. GIVEN ABOVE
SYNOPTIC/MESOSCALE FACTORS...SOME POTENTIAL APPEARS TO EXIST FOR
SOME LOCALLY HIGHER SNOWFALL AMOUNTS IN EXCESS OF 8 INCHES ACROSS
THE FAR SOUTH/SOUTHWEST...BUT CONFIDENCE REMAINS LOW IN
EXTENT/COVERAGE OF THESE TYPE OF ACCUMULATIONS. PREVIOUS FORECAST
APPEARS TO HAVE SITUATION COVERED WELL...AND HAVE MADE JUST A
MINOR UPWARD ADJUSTMENT IN STORM TOTAL ACCUMS ACROSS THE WARNING
AREA...AND TO HIGHLIGHT POSSIBILITY OF LOCALLY HIGHER AMOUNTS.
ONLY OTHER TWEAK TO FORECAST WAS TO INCREASE POPS A BIT MONDAY
MORNING AS ENSEMBLE GUIDANCE APPEARS TO SLOW DEPARTURE OF
WEAKENING DEFORMATION/TROWAL FORCING. NO CHANGES WERE MADE TO THE
CURRENT HEADLINES AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 720 PM EDT SUN MAR 24 2013/
AVIATION...
00Z TAFS...AN AREA OF MODERATE TO HEAVY SNOW FROM PORTIONS OF
NORTHWEST INDIANA INTO EAST CENTRAL INDIANA WILL CONTINUE TO LIFT
NORTHWARD THIS EVENING WHILE BECOMING MORE WEST TO EAST ORIENTED
OVER THE NEXT SEVERAL HOURS. HEAVIEST SNOW AT KFWA IS STILL
EXPECTED IN THE 02Z-06Z TIMEFRAME WITH LIGHT SNOW THEN EXPECTED TO
CONTINUE THROUGH THE REMAINDER OF THE OVERNIGHT HOURS INTO MONDAY
MORNING. A SHARP SOUTH TO NORTH LOW LEVEL MOISTURE GRADIENT STILL
PROVIDES SOME LOW CONFIDENCE IN TERMS OF CIG/VSBY IMPACTS FROM
SNOW AT KSBN. DO SEE SOME POTENTIAL FOR AT LEAST BRIEF WINDOW OF
IFR VSBYS LATER THIS EVENING AT KSBN...WITH GENERALLY MVFR CONDS
THEN EXPECTED THROUGH THE REMAINDER OF THE OVERNIGHT. GUSTY
NORTHEAST WINDS TO 25 KNOTS OR GREATER WILL CONTINUE THIS
EVENING...BACKING MORE NORTHERLY TOWARD MORNING AS SFC LOW
PRESSURE SOUTH OF THE AREA SHIFTS EASTWARD.
PREV DISCUSSION... /ISSUED 337 PM EDT SUN MAR 24 2013/
SHORT TERM...
TONIGHT...MONDAY...MONDAY NIGHT...
LATEST WATER VAPOR IMAGERY SHOWING POTENT UPPER TROUGH AND
ASSOCIATED VORT MAX PUSHING ACROSS MISSOURI THIS AFTERNOON. LOW-MID
LEVEL ASCENT AHEAD OF THIS FEATURE IS RESULTING IN A LARGE SWATH OF
HEAVY SNOW OVER EASTERN MO AND WEST CENTRAL IL. RADAR IMAGERY
DEPICTING CONVECTIVE ELEMENTS EMBEDDED WITHIN THIS SNOW BAND WHICH
MAY ACT TO HINDER MOISTURE TRANSPORT NORTHWARD INTO OUR AREA AS THIS
SYSTEM CONTINUES TO MOVE E/NE THIS EVENING. 12Z RAOBS CONFIRMING
LATEST RAP ANALYSIS SHOWING STRONG UPPER JET TRAVERSING THROUGH THE
BASE OF THIS TROUGH...ASSOCIATED UPPER LEVEL DIVERGENCE EXPECTED TO
AID IN THE CONTINUATION OF HEAVY SNOW BAND AS IT MOVES INTO
CENTRAL/NORTHERN INDIANA TONIGHT. MODELS IN DECENT AGREEMENT IN NE
TRACK OF SFC LOW...BRINGING IT INTO NORTHERN KY BY 00Z MON AND UP
INTO SW OH BY 12Z MON...PLACING OUR SOUTHERN CWA IN FAVORABLE AREA
FOR FOR HEAVY SNOW. KEY COMPONENT IN THE EVOLUTION OF THIS SYSTEM
THAT WILL ACT TO LIMIT SNOW ACCUMULATIONS IS THE EASTWARD
PROGRESSION OF UPPER JET DYNAMICS AND THE RESULTING COASTAL TRANSFER
OF ENERGY. THIS WILL RAPIDLY DISSIPATE OH VALLEY SFC LOW MONDAY IN
FAVOR OF INTENSIFICATION OF COASTAL LOW AS CLOSED UPPER LOW
CONTINUES ON EASTWARD TRACK AND BECOMES NEARLY VERTICALLY STACKED
WITH SFC LOW OVER OH VALLEY 09-12Z MON. THAT SAID...THERE STILL
EXISTS A 12 HOUR WINDOW...00Z-12Z MON...OF FAVORABLE CONDITIONS FOR
ACCUMULATING SNOW AS ALL MODELS IN GOOD AGREEMENT WITH PRODUCING 6-8
INCHES OVER THE FAR SOUTHERN PORTION OF THE CWA AS 80-100M 500MB HT
FALLS WILL REACH UP INTO THE SOUTHERN CWA AS UPPER LOW TRACKS
THROUGH KY OVERNIGHT. AND WHILE MODELS VARY ON DEGREE OF DEEP
MOISTURE AVAILABLE...AMPLE LOW LEVEL MOISTURE ALONG WITH BETTER
ALIGNMENT OF OMEGA AND DGZ THAN PREVIOUS RUNS WILL ALSO FAVOR A GOOD
SHOT AT HVY SNOW FOR AT LEAST A BRIEF PERIOD OF TIME OVERNIGHT
ACROSS THE SOUTHERN TIER OF THE FCST AREA. WILL THEREFORE CONTINUE
WITH WARNING/ADV AREAS AND KEEP NORTHERN TIER WITHOUT HEADLINES AS
DISTINCT CUTOFF IN SNOW EXPECTED NORTH OF US6. IN THE WAKE OF THIS
SYSTEM FLOW WILL GRADUALLY BACK FROM NE TO N/NW LATE IN THE DAY
MONDAY AND BRING CHANCE FOR LES INTO OUR EXTREME NW CWA. DESPITE
UNIFORM NORTHERLY FLOW DOWN THE LONG AXIS OF LAKE MICHIGAN...LACK OF
COLD AIR WILL YIELD MARGINAL/SUB MARGINAL DELTA T AND THEREFORE
HINDER ACCUMULATIONS.
LONG TERM...
TUESDAY THROUGH SUNDAY...INCREASED SNOW CHANCES TUESDAY AND TUESDAY
NIGHT OVER AREAS DOWNSTREAM OF LAKE MICHIGAN AS VERY COLD AIR
CONTINUES TO SPREAD SOUTH OVER THE WESTERN GREAT LAKES REGION. DELTA
T VALUES RATHER MODEST AT 12C TO 14C...BUT A LONG LAKE AXIS FETCH
WITH LIKELY PRECONDITIONING FROM LAKE SUPERIOR SHOULD ALLOW FOR SOME
ORGANIZATION OF SNOW SHOWERS OVER THE LAKE. RAISED SNOWFALL AMOUNTS
TUESDAY...HOWEVER...DAYTIME HEATING SHOULD LIMIT SNOW ACCUMULATIONS.
INVERSIONS HEIGHTS SHOULD FALL LATE TUESDAY NIGHT...BRINGING AN END
TO THE SNOW SHOWERS. HIGH AND LOW FCST TEMPERATURES ARE CHALLENGING
EARLY IN THE PERIOD GIVEN LOCATIONS AND AMOUNTS OF LINGERING SNOW
COVER AND A GRADUALLY MODIFYING AIRMASS. ANTICIPATED SOME SNOW COVER
SHOULD BE REMAINING OVER THE SOUTHERN THIRD OF THE AREA...SO HAVE
MADE SOME TEMPERATURE MODIFICATIONS TO THESE AREAS. OTHERWISE...
TEMPERATURES SHOULD STILL STRUGGLE TO GET BACK TO NORMAL. PREFERRED
THE COLDER GFS MEAN MOS TEMPERATURES THAT SEEM TO TAKE INTO ACCOUNT
A CHILLY MODIFYING AIRMASS. THE ECMWF IS EVEN COLDER THAN THE
GFS...WITH 850 MB TEMPS STAYING BELOW 0C EXCEPT FOR LATE SUNDAY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 10 AM EDT /9 AM CDT/ MONDAY FOR
INZ008-009-012>018.
WINTER STORM WARNING UNTIL 10 AM EDT MONDAY FOR INZ020-022>027-
032>034.
MI...NONE.
OH...WINTER WEATHER ADVISORY UNTIL 2 PM EDT MONDAY FOR OHZ004-005-015-
016.
WINTER STORM WARNING UNTIL 2 PM EDT MONDAY FOR OHZ024-025.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT TUESDAY FOR LMZ043-046.
&&
$$
SHORT TERM...JAL
LONG TERM...SKIPPER
AVIATION...MARSILI
UPDATE...MARSILI
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
720 PM EDT SUN MAR 24 2013
.AVIATION...
00Z TAFS...AN AREA OF MODERATE TO HEAVY SNOW FROM PORTIONS OF
NORTHWEST INDIANA INTO EAST CENTRAL INDIANA WILL CONTINUE TO LIFT
NORTHWARD THIS EVENING WHILE BECOMING MORE WEST TO EAST ORIENTED
OVER THE NEXT SEVERAL HOURS. HEAVIEST SNOW AT KFWA IS STILL
EXPECTED IN THE 02Z-06Z TIMEFRAME WITH LIGHT SNOW THEN EXPECTED TO
CONTINUE THROUGH THE REMAINDER OF THE OVERNIGHT HOURS INTO MONDAY
MORNING. A SHARP SOUTH TO NORTH LOW LEVEL MOISTURE GRADIENT STILL
PROVIDES SOME LOW CONFIDENCE IN TERMS OF CIG/VSBY IMPACTS FROM
SNOW AT KSBN. DO SEE SOME POTENTIAL FOR AT LEAST BRIEF WINDOW OF
IFR VSBYS LATER THIS EVENING AT KSBN...WITH GENERALLY MVFR CONDS
THEN EXPECTED THROUGH THE REMAINDER OF THE OVERNIGHT. GUSTY
NORTHEAST WINDS TO 25 KNOTS OR GREATER WILL CONTINUE THIS
EVENING...BACKING MORE NORTHERLY TOWARD MORNING AS SFC LOW
PRESSURE SOUTH OF THE AREA SHIFTS EASTWARD.
&&
.PREV DISCUSSION... /ISSUED 337 PM EDT SUN MAR 24 2013/
SHORT TERM...
TONIGHT...MONDAY...MONDAY NIGHT...
LATEST WATER VAPOR IMAGERY SHOWING POTENT UPPER TROUGH AND
ASSOCIATED VORT MAX PUSHING ACROSS MISSOURI THIS AFTERNOON. LOW-MID
LEVEL ASCENT AHEAD OF THIS FEATURE IS RESULTING IN A LARGE SWATH OF
HEAVY SNOW OVER EASTERN MO AND WEST CENTRAL IL. RADAR IMAGERY
DEPICTING CONVECTIVE ELEMENTS EMBEDDED WITHIN THIS SNOW BAND WHICH
MAY ACT TO HINDER MOISTURE TRANSPORT NORTHWARD INTO OUR AREA AS THIS
SYSTEM CONTINUES TO MOVE E/NE THIS EVENING. 12Z RAOBS CONFIRMING
LATEST RAP ANALYSIS SHOWING STRONG UPPER JET TRAVERSING THROUGH THE
BASE OF THIS TROUGH...ASSOCIATED UPPER LEVEL DIVERGENCE EXPECTED TO
AID IN THE CONTINUATION OF HEAVY SNOW BAND AS IT MOVES INTO
CENTRAL/NORTHERN INDIANA TONIGHT. MODELS IN DECENT AGREEMENT IN NE
TRACK OF SFC LOW...BRINGING IT INTO NORTHERN KY BY 00Z MON AND UP
INTO SW OH BY 12Z MON...PLACING OUR SOUTHERN CWA IN FAVORABLE AREA
FOR FOR HEAVY SNOW. KEY COMPONENT IN THE EVOLUTION OF THIS SYSTEM
THAT WILL ACT TO LIMIT SNOW ACCUMULATIONS IS THE EASTWARD
PROGRESSION OF UPPER JET DYNAMICS AND THE RESULTING COASTAL TRANSFER
OF ENERGY. THIS WILL RAPIDLY DISSIPATE OH VALLEY SFC LOW MONDAY IN
FAVOR OF INTENSIFICATION OF COASTAL LOW AS CLOSED UPPER LOW
CONTINUES ON EASTWARD TRACK AND BECOMES NEARLY VERTICALLY STACKED
WITH SFC LOW OVER OH VALLEY 09-12Z MON. THAT SAID...THERE STILL
EXISTS A 12 HOUR WINDOW...00Z-12Z MON...OF FAVORABLE CONDITIONS FOR
ACCUMULATING SNOW AS ALL MODELS IN GOOD AGREEMENT WITH PRODUCING 6-8
INCHES OVER THE FAR SOUTHERN PORTION OF THE CWA AS 80-100M 500MB HT
FALLS WILL REACH UP INTO THE SOUTHERN CWA AS UPPER LOW TRACKS
THROUGH KY OVERNIGHT. AND WHILE MODELS VARY ON DEGREE OF DEEP
MOISTURE AVAILABLE...AMPLE LOW LEVEL MOISTURE ALONG WITH BETTER
ALIGNMENT OF OMEGA AND DGZ THAN PREVIOUS RUNS WILL ALSO FAVOR A GOOD
SHOT AT HVY SNOW FOR AT LEAST A BRIEF PERIOD OF TIME OVERNIGHT
ACROSS THE SOUTHERN TIER OF THE FCST AREA. WILL THEREFORE CONTINUE
WITH WARNING/ADV AREAS AND KEEP NORTHERN TIER WITHOUT HEADLINES AS
DISTINCT CUTOFF IN SNOW EXPECTED NORTH OF US6. IN THE WAKE OF THIS
SYSTEM FLOW WILL GRADUALLY BACK FROM NE TO N/NW LATE IN THE DAY
MONDAY AND BRING CHANCE FOR LES INTO OUR EXTREME NW CWA. DESPITE
UNIFORM NORTHERLY FLOW DOWN THE LONG AXIS OF LAKE MICHIGAN...LACK OF
COLD AIR WILL YIELD MARGINAL/SUB MARGINAL DELTA T AND THEREFORE
HINDER ACCUMULATIONS.
LONG TERM...
TUESDAY THROUGH SUNDAY...INCREASED SNOW CHANCES TUESDAY AND TUESDAY
NIGHT OVER AREAS DOWNSTREAM OF LAKE MICHIGAN AS VERY COLD AIR
CONTINUES TO SPREAD SOUTH OVER THE WESTERN GREAT LAKES REGION. DELTA
T VALUES RATHER MODEST AT 12C TO 14C...BUT A LONG LAKE AXIS FETCH
WITH LIKELY PRECONDITIONING FROM LAKE SUPERIOR SHOULD ALLOW FOR SOME
ORGANIZATION OF SNOW SHOWERS OVER THE LAKE. RAISED SNOWFALL AMOUNTS
TUESDAY...HOWEVER...DAYTIME HEATING SHOULD LIMIT SNOW ACCUMULATIONS.
INVERSIONS HEIGHTS SHOULD FALL LATE TUESDAY NIGHT...BRINGING AN END
TO THE SNOW SHOWERS. HIGH AND LOW FCST TEMPERATURES ARE CHALLENGING
EARLY IN THE PERIOD GIVEN LOCATIONS AND AMOUNTS OF LINGERING SNOW
COVER AND A GRADUALLY MODIFYING AIRMASS. ANTICIPATED SOME SNOW COVER
SHOULD BE REMAINING OVER THE SOUTHERN THIRD OF THE AREA...SO HAVE
MADE SOME TEMPERATURE MODIFICATIONS TO THESE AREAS. OTHERWISE...
TEMPERATURES SHOULD STILL STRUGGLE TO GET BACK TO NORMAL. PREFERRED
THE COLDER GFS MEAN MOS TEMPERATURES THAT SEEM TO TAKE INTO ACCOUNT
A CHILLY MODIFYING AIRMASS. THE ECMWF IS EVEN COLDER THAN THE
GFS...WITH 850 MB TEMPS STAYING BELOW 0C EXCEPT FOR LATE SUNDAY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 10 AM EDT /9 AM CDT/ MONDAY FOR
INZ008-009-012>018.
WINTER STORM WARNING UNTIL 10 AM EDT MONDAY FOR INZ020-022>027-
032>034.
MI...NONE.
OH...WINTER WEATHER ADVISORY UNTIL 2 PM EDT MONDAY FOR OHZ004-005-015-
016.
WINTER STORM WARNING UNTIL 2 PM EDT MONDAY FOR OHZ024-025.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT TUESDAY FOR LMZ043-046.
&&
$$
SHORT TERM...JAL
LONG TERM...SKIPPER
AVIATION...MARSILI
AREA FORECAST DISCUSSION
NWS DES MOINES IA
338 PM CDT SAT MAR 23 2013
.SHORT TERM /TONIGHT/...
SYSTEM CONTINUES TO DIG SOUTHWARD THROUGH THE FRONT RANGE THIS
AFTERNOON WITH WIDESPREAD SNOWFALL ACROSS THE PLAINS. RECENTLY...
PRECIPITATION HAS BEEN EXPANDING FROM EASTERN KANSAS INTO WESTERN
MISSOURI IN WARM ADVECTION AIR OF THE SYSTEM. SOME MID TO HIGH
CLOUDINESS HAS SPREAD ACRS IOWA ALTHOUGH LOW LEVEL DRY AIR CONTINUES
TO MOVE IN FROM THE NORTHEAST. RECENT MODEL OUTPUT FROM THE 12Z GFS
PLUS THE HOURLY UPDATES FROM THE RAP CONTINUE TO INDICATE LATER
ONSET FOR MUCH OF THE FORECAST AREAS TONIGHT. THE NAM HAS BEEN MOST
AGGRESSIVE IN SPREADING SNOW INTO THE STATE THIS EVENING BUT SEEMS
TO BE THE ODD MODEL OUT AT THIS POINT WITH 18Z RUN BACKING OFF THE
MORE PROGRESSIVE 12Z RUN. HAVE GENERALLY STALLED THE ONSET OF
PRECIPITATION ACRS CENTRAL IOWA UNTIL LATER EVENING AND ACROSS THE
NORTH UNTIL WELL AFTER MIDNIGHT. NEWEST 18Z RAP WOULD NOT EVEN
BRING SNOW INTO DES MOINES UNTIL NEARLY 12Z ON SUNDAY AND REMAINS
DRY NORTH OF HIGHWAY 30.
ALL MODELS ALSO HAVE A BAND OF SNOW ACROSS NORTHWEST IOWA TONIGHT IN
A BAND OF WEAKER FORCING AHEAD OF UPPER CUTOFF CURRENTLY IN THE
DAKOTAS. ALREADY SOME LIGHT SNOW REPORTED IN SIOUX CITY AND HAVE
MAINTAINED THE POPS IN THE FAR WEST AND NORTHWEST FOR THIS AXIS OF
PRECIPITATION OVERNIGHT. ADVISORY WILL REMAIN INTACT FOR CURRENTLY
LOCATIONS ALTHOUGH HEAVIEST SNOWFALL APPEARS TO BE PRIMARILY IN THE
FAR SOUTHEAST OVERNIGHT WHERE AROUND 2 TO POSSIBLY 3 INCHES IS
EXPECTED. DES MOINES METRO MAY SEE AN INCH OR SO WITH LIGHT AMOUNTS
TOWARD THE NORTH.
.LONG TERM /SUNDAY THROUGH SATURDAY/...
MAIN FORECAST CONCERN WILL BE WITH PRECIPITATION CHANCES FOR
SUNDAY AND MONDAY. EXPECT WIDESPREAD SNOW TO BE ONGOING AT
BEGINNING OF PERIOD...ESPECIALLY ACROSS THE SOUTH AS LOW PRESSURE
SYSTEM PUSHES EAST ACROSS MISSOURI. SOUNDINGS AND CROSS SECTIONS
INDICATE GOOD SATURATION AND FORCING...ESPECIALLY ACROSS THE
SOUTH. FORCING BECOMES MUCH WEAKER FURTHER NORTH AWAY FROM THE
LOW...BUT ENOUGH TO RESULT IN AT LEAST LIGHT SNOWFALL THROUGHOUT
THE DAY MONDAY. BEST FORCING WILL BE EARLY...BEFORE 18Z AND EXPECT
TO SEE BEST SNOWFALL RATES THEN. BEST FORCING IS ABOVE THE
DENDRITIC LAYER...AND DO NOT ANTICIPATE SNOWFALL RATIOS TO BE MUCH
HIGHER THAN 10/1. DRY AIR WILL BEGIN TO PUSH BACK IN BEHIND SYSTEM
OVERNIGHT MONDAY...WITH PRECIPITATION ENDING ACROSS THE NE.
HOWEVER...GOOD VORT MAX PUSHING AROUND LOW WILL KEEP LINGERING
SNOW CHANCES ACROSS THE SW...BUT AGAIN WITH WEAKER FORCING ONLY
LIGHT SNOW EXPECTED. LINGERING LOW LEVEL SATURATION WILL ALLOW FOR
LINGERING LIGHT SNOW AND FLURRIES THROUGH MONDAY WITH COLD SURFACE
TEMPERATURES. SYSTEM WILL CONTINUE TO PULL EAST...AND MAY SEE
ADDITIONAL LINGERING FLURRIES THROUGH TUESDAY. TOTAL ACCUMULATIONS
ARE SIMILAR TO GOING WITH HIGHER TOTALS ACROSS THE SOUTH. WINDS WILL
BE STRONG BEHIND LOW...BUT WILL GENERALLY STAY BELOW 30MPH AND
WILL LEAD TO SOME IMPACTS...MOSTLY WITH ROADS AND REDUCED
VISIBILITIES....BUT DO NOT ANTICIPATE SIGNIFICANT IMPACTS WITH
SNOWFALL. GIVEN DURATION OF SNOWFALL...ADVISORY SEEMS WARRANTED
AND WILL LEAVE AS IS. HOWEVER...MAY NEED TO BE EXTENDED IN TIME
ACROSS THE SOUTH FOR LINGER SNOWFALL INTO MONDAY NIGHT...BUT WILL
LEAVE FOR FUTURE UPDATES AS MODELS CONTINUE TO VARY ON PLACEMENT
OF LOW.
TEMPERATURES WILL BEGIN TO WARM BY MID WEEK WITH SOUTHERLY SURFACE
FLOW AND INCREASING WAA. MODELS BRING ANOTHER LOW PRESSURE SYSTEM
ACROSS CANADA...WITH TRAILING FRONTAL BOUNDARY ACROSS MIDWEST.
THIS WILL BE FOCUS FOR PRECIPITATION CHANCES THROUGH THE WEEKEND.
HOWEVER...WITH WARMER TEMPERATURES PRECIPITATION LIKELY RAIN.
STILL SOME UNCERTAINTY IN TIMING AND LOCATION OF RAIN...AND HAVE
LEFT SLIGHT CHANCES FOR NOW.
&&
.AVIATION...23/18Z
CEILINGS WILL GRADUALLY LOWER DURING THE AFTERNOON...ALTHOUGH REMAIN
VFR ACROSS THE FORECAST AREA. PRECIPITATION...MAINLY SNOW WILL MOVE
INTO CENTRAL IOWA OVERNIGHT AND PERSIST INTO SUNDAY. VFR CONDITIONS
WILL GIVE WAY TO WIDESPREAD MVFR TO IFR CONDITIONS AS THE SNOW
SPREAD ACROSS THE STATE OVERNIGHT. BOTH VSBYS AND CIGS WILL BE
RESTRICTED BY THE SNOWFALL WHICH IS FORECAST TO PERSIST INTO
SUNDAY...ALBEIT RATHER LIGHT. WINDS WILL GRADUALLY STRENGTHEN BY
SUNDAY MORNING AS WELL AND BECOME NORTHERLY.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 7 PM CDT
SUNDAY FOR ADAIR-ADAMS-APPANOOSE-CASS-CLARKE-DAVIS-DECATUR-LUCAS-
MADISON-MAHASKA-MARION-MONROE-RINGGOLD-TAYLOR-UNION-WAPELLO-
WARREN-WAYNE.
&&
$$
SHORT TERM...COGIL
LONG TERM...AWB
AVIATION...COGIL
AREA FORECAST DISCUSSION
NWS TOPEKA KS
313 PM CDT SAT MAR 23 2013
.DISCUSSION...
20Z WATER VAPOR SHOWS A SHORTWAVE OVER THE CO ROCKIES DIGGING
SOUTHEAST. A SURFACE LOW WAS LOCATED OVER THE EASTERN NM HIGH PLAINS
WITH A BROAD AND WEAK SURFACE RIDGE FROM THE NORTHERN ROCKIES INTO
THE GREAT LAKES. THE LITTLE BIT OF INSOLATION WE HAVE RECEIVED
COUPLED WITH NEUTRAL OR WEAK WARM AIR ADVECTION HAS HELPED WARM
TEMPS INTO THE MID AND UPPER 30S. AREA OF SNOW AND RAIN OVER EASTERN
KS IS EVIDENCE OF LARGE SCALE FORCING SPREADING OVER EASTERN KS.
FOR TONIGHT AND SUNDAY...THE MODELS HAVE TRENDED SLIGHTLY SOUTH WITH
THE TRACK OF THE UPPER WAVE...WHICH SEEMS TO BE SUPPORTED BY THE
LATEST WATER VAPOR IMAGERY. BECAUSE OF THIS THE LOCATION OF THE
HEAVIER SNOWFALL IS NOW SHIFTED TO THE SOUTHEAST. THERE SHOULD
CONTINUE TO BE GOOD LARGE SCALE FORCING THROUGH THE EVENING SO HAVE
MAINTAINED THE 100 PERCENT POPS OVERNIGHT...AND SNOW IS EXPECTED TO
SPREAD ACROSS EASTERN KANSAS THIS EVENING. MODELS POINT TO THE
STRONGEST VERTICAL MOTION BETWEEN MIDNIGHT AND 7AM AS THE DIFFLUENCE
AND DEFORMATION ZONE OF THE UPPER WAVE PASS OVERHEAD...PUTTING EAST
CENTRAL KANSAS IN THE MOST LIKELY AREA TO RECEIVE THE HIGHER SNOW
AMOUNTS. THEREFORE THINK A PERIOD OF MODERATE TO HEAVY SNOW IS STILL
LIKELY TO DEVELOP WITH ACCUMULATIONS OF 4 TO 7 INCHES FOR AREAS
ALONG AND SOUTH OF A COUNCIL GROVE TO HIAWATHA LINE. NORTH WINDS ARE
GOING TO INCREASE AND GUST TO AROUND 30 MPH. HOWEVER GIVEN HOW WARM
GROUND TEMPERATURES ARE AND THE WET NATURE OF THE SNOW...DRIFTING
SNOW MAY BE MUTED A BIT. VISIBILITIES ARE PROBABLY GOING TO STILL BE
LOWERED TO LESS THAN A MILE IN THE BANDS OF HEAVY SNOW.
BECAUSE OF THE LIMITED ACCUMULATIONS THIS AFTERNOON AND REDUCED
SNOW AMOUNTS EXPECTED OVERNIGHT...THE WINTER STORM WARNING FOR
NORTH CENTRAL AND PARTS OF NORTHEAST KANSAS HAS BEEN DOWNGRADED TO
A WINTER WEATHER ADVISORY. SNOW ACCUMULATIONS ARE NOW FORECAST TO BE
3 TO 5 INCHES WHICH MAY BE A LITTLE ON THE HIGH SIDE. THIS IS FOR
AREA GENERALLY ALONG AND NORTHWEST OF A HERINGTON TO SENECA LINE. A
WINTER STORM WARNING REMAINS IN EFFECT FOR EAST CENTRAL AND
PARTS OF NORTHEAST KANSAS...FOR THE AREAS MENTION ABOVE.
WITH COLD AIR ADVECTION INCREASING OVERNIGHT...LOWS SHOULD FALL INTO
THE MID AND UPPER 20S. THE COLD AIR ADVECTION CONTINUES THROUGH THE
DAY SUNDAY. THIS COMBINED WITH OVERCAST SKIES SHOULD KEEP AFTERNOON
HIGHS IN THE LOW TO MID 30S.
WOLTERS
SUNDAY NIGHT THROUGH MONDAY...SECONDARY LOBE OF ENERGY CONTINUES TO
ROTATE AROUND THE BACK OF THE UPPER LOW AND INTO THE FORECAST AREA
ON MONDAY. OVERNIGHT LOWS IN MIXED LOW LEVELS EXPECTED IN THE UPPER
TEENS TO 20S. MAY BE ENOUGH LIFT AND MOISTURE FOR SOME FLURRIES
MONDAY AFTERNOON BUT ACCUMULATION IS NOT ANTICIPATED. HIGHS MONDAY
IN THE LOW TO MID 30S.
SKIES SLOWLY CLEAR MONDAY NIGHT AND GIVEN LIGHT WINDS AS THE SURFACE
HIGH PASSES OVER WILL SEE ANOTHER NIGHT IN THE TEENS TO LOW 20S.
WARMING BACK TO THE UPPER 30S NEAR 40 AS SOUTHERLY FLOW RETURNS TO
THE SURFACE AND WAA ALSO RETURNS. WEAK SHORTWAVE PROGGED TO CROSS
ALONG OUR NORTHERN BORDER ON WEDNESDAY BUT SIGNAL IS WEAK ATTM AND
WILL NOT YET ADD POPS. MAY BE ABLE TO REACH HIGHS NEAR 50 BY LATE
AFTERNOON.
THURS-SAT A BIT UNSETTLED WITH MODEL DIFFERENCES IN PLACEMENT OF A
FRONT ACROSS THE CENTRAL PLAINS. COULD SEE A RETURN OF
PRECIPITATION THURSDAY AS ANOTHER WAVE MOVES OVER THE BOUNDARY IN
EASTERN KS. EC KEEPS FRONT SOUTH OF THE FORECAST AREA FRIDAY INTO
SATURDAY WITH SOME REINFORCEMENT FROM THE UPPER LOW MOVING ACROSS
EASTERN CANADA AND PUSHING COLDER AIR SOUTH. GFS A BIT FARTHER NORTH
WITH THE BOUNDARY FRIDAY BUT DROPS IT SOUTHWARD ON SATURDAY. MAY BE
SEEING A WARM BIAS IN THE HIGH TEMPERATURES BY THE LATE WEEK AND
WEEKEND. HAVE GONE MIDDLE TO UPPER 50S BUT COULD BE SLIGHTLY COOLER
DEPENDING ON WHERE THE FRONT ENDS UP AND ANY DYNAMIC COOLING FROM
RAINFALL.
67
&&
.AVIATION...
CONFIDENCE IS HIGH THAT CONDITIONS WILL DETERIORATE AS LARGE SCALE
FORCING FROM THE SHORTWAVE OVER THE CO ROCKIES CONTINUES TO SPREAD
OVER NORTHEAST KS. BASED ON NAM AND RAP FORECAST SOUNDINGS...PRECIP
IS EXPECTED TO INITIALLY BE MIXED WITH A CHANGE TO SN BY 00Z. BEST
VERTICAL MOTION LOOKS TO OCCUR BETWEEN 05Z AND 09Z SUNDAY...SO HAVE
THE LOWEST CIGS AND VSBY DURING THIS PERIOD. WHILE THE INTENSITY OF
THE SN DECREASES AFTER 12Z SUNDAY...GUSTY NORTH WINDS MAY KEEP IFR
VSBY FOR A LITTLE WHILE UNTIL THE SNOW COMES TO AN END. BUT I THINK
THERE SHOULD BE A GRADUAL IMPROVEMENT THROUGH THE LATE MORNING
HOURS.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 1 PM CDT SUNDAY FOR
KSZ012-024-026-037>040-054>056-058-059.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT SUNDAY FOR
KSZ008>011-020>023-034>036.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1229 PM CDT SAT MAR 23 2013
.DISCUSSION...
SEE PREV DISCUSSION.
&&
.AVIATION...
CONFIDENCE IS HIGH THAT CONDITIONS WILL DETERIORATE AS LARGE SCALE
FORCING FROM THE SHORTWAVE OVER THE CO ROCKIES CONTINUES TO SPREAD
OVER NORTHEAST KS. BASED ON NAM AND RAP FORECAST SOUNDINGS...PRECIP
IS EXPECTED TO INITIALLY BE MIXED WITH A CHANGE TO SN BY 00Z. BEST
VERTICAL MOTION LOOKS TO OCCUR BETWEEN 05Z AND 09Z SUNDAY...SO HAVE
THE LOWEST CIGS AND VSBY DURING THIS PERIOD. WHILE THE INTENSITY OF
THE SN DECREASES AFTER 12Z SUNDAY...GUSTY NORTH WINDS MAY KEEP IFR
VSBY FOR A LITTLE WHILE UNTIL THE SNOW COMES TO AN END. BUT I THINK
THERE SHOULD BE A GRADUAL IMPROVEMENT THROUGH THE LATE MORNING
HOURS.
WOLTERS
&&
.PREV DISCUSSION... /439 AM CDT SAT MAR 23 2013/
MAIN FOCUS FOR THE FORECAST IS ON THE SIGNIFICANT LATE-MARCH WINTER
STORM THAT WILL BE IMPACTING THE ENTIRE FORECAST AREA THROUGH THE
WEEKEND. AS OF 09Z...THE SURFACE LOW ASSOCIATED WITH THIS SYSTEM WAS
LOCATED JUST WEST OF THE OKLAHOMA/TEXAS PANHANDLES WITH THE UPPER
LEVEL TROUGH OVER THE NORTHERN ROCKIES AND CONTINUING TO DIG FURTHER
SOUTHWARD. THIS SYSTEM WAS PRODUCING LIGHT TO MODERATE SNOW ACROSS
NORTHWESTERN KANSAS EARLY THIS MORNING...WITH PRECIPITATION
GRADUALLY SPREADING EASTWARD ACROSS THE STATE THROUGH THE DAY AS THE
UPPER LOW TRACKS DIRECTLY OVER THE REGION. THIS MORNING...MODEL
SOUNDINGS SHOW THAT THERE MAY BE ENOUGH LOW-LEVEL MOISTURE IN PLACE
OVER FAR NORTHEAST AND EAST CENTRAL KANSAS...ALONG WITH TEMPERATURES
NEAR THE FREEZING MARK...TO PRODUCE SOME AREAS OF LIGHT
SNOW...FREEZING DRIZZLE OR SLEET. THE POTENTIAL FOR MEASURABLE
PRECIPITATION FROM THIS LIGHT ACTIVITY THOUGH IS FAIRLY LOW.
THE PRECIPITATION CURRENTLY OVER NORTHWEST KANSAS WILL PROGRESS
EASTWARD INTO NORTH CENTRAL AND CENTRAL KANSAS THIS MORNING...WITH
PRECIPITATION QUICKLY OVERSPREADING THE ENTIRE FORECAST AREA DURING
THE AFTERNOON HOURS. TEMPERATURES TODAY WILL PLAY A MAJOR ROLE IN
PRECIPITATION TYPES ACROSS THE AREA...ALONG WITH WHEN TRANSITIONING
PRECIPITATION CAN BE EXPECTED. TEMPERATURES ACROSS NORTHEAST AND
EAST CENTRAL KANSAS ARE LOOKING TO WARM TO NEAR 40 DEGREES
TODAY...RESULTING IN PRECIPITATION PREDOMINANTLY BEING IN THE FORM
OF RAIN THROUGH MUCH OF THE DAY. DEPENDING UPON HOW QUICKLY
PRECIPITATION SPREADS THAT FAR EAST...COULD SEE A RAIN/SNOW MIX
INITIALLY BEFORE TRANSITIONING OVER THE RAIN AND CAN EXPECT A BRIEF
TRANSITION PERIOD ONCE AGAIN DURING THE LATE AFTERNOON/EARLY EVENING
HOURS AS TEMPERATURES DROP BELOW FREEZING. SNOWFALL ACCUMULATIONS
ACROSS THIS REGION CERTAINLY WILL BE DEPENDENT UPON HOW LONG
PRECIPITATION REMAINS IN THE FORM OF RAIN. TEMPERATURES ACROSS NORTH
CENTRAL AND CENTRAL KANSAS LOOK TO BE NEAR OR JUST ABOVE THE
FREEZING MARK TODAY...SO EXPECT PRECIPITATION TO BE MOSTLY IN THE
FORM OF SNOW. MODELS CONTINUE TO HIGHLIGHT THE LATE AFTERNOON
THROUGH EARLY SUNDAY MORNING TIMEFRAME AS THE BEST TIME FOR
ACCUMULATING PRECIPITATION. IT IS DURING THIS PERIOD THAT MODELS
SHOW GOOD Q-VECTOR CONVERGENCE ALONG WITH DECENT MID-LEVEL
FRONTOGENESIS AND ISENTROPIC LIFT TO HELP SUPPORT AREAS OF MODERATE
TO AT TIMES HEAVY PRECIPITATION. IT IS WORTH NOTING THAT MODEL
SOUNDINGS ARE SHOWING A BRIEF WINDOW LATE TONIGHT IN WHICH WE START
LOSING SOME OF THE SATURATION IN THE DENDRITIC GROWTH ZONE.
HOWEVER...MOISTURE PROFILES LOOK TO QUICKLY RE-SATURATE SO ONLY
EXPECT MAYBE AN HOUR OR TWO OF LIGHTER PRECIPITATION. BY SUNDAY
MORNING...THE UPPER LEVEL TROUGH LOOKS TO BECOME MORE NEGATIVELY
TILTED AS IT SHIFTS EAST OF THE FORECAST AREA...WITH THE UPPER LOW
SITUATED JUST SOUTHEAST OF THE CWA. MODELS HAVE NOT BEEN
HIGHLIGHTING MUCH ADDITIONAL PRECIPITATION WRAPPING AROUND THE LOW
AS IT EXITS TO THE EAST...SO EXPECT PRECIPITATION TO GRADUALLY
DIMINISH FROM WEST TO EAST ACROSS THE CWA THROUGH THE DAY ON SUNDAY.
NORTH CENTRAL AND CENTRAL KANSAS SHOULD START SEEING THIS DECLINE IN
PRECIPITATION DURING THE EARLY MORNING HOURS WITH POSSIBLY A FEW
LINGERING SNOW SHOWERS OR FLURRIES BY THE AFTERNOON. FAR NORTHEAST
AND EAST CENTRAL KANSAS COULD STILL BE IMPACTED BY MODERATE SNOW
SUNDAY MORNING BEFORE TRANSITIONING TO LIGHT SNOW LATE MORNING INTO
THE EARLY AFTERNOON. THERE IS STILL UNCERTAINTY AMONGST THE MODELS
WITH REGARDS TO HOW QUICKLY PRECIPITATION WILL EXIT EAST OF THE AREA
THROUGH THE DAY ON SUNDAY...BUT IT LOOKS TO BE WELL EAST OF THE AREA
BY SUNDAY EVENING. HOWEVER...WITH SOME LOW LEVEL MOISTURE STILL IN
PLACE OVER THE REGION...COULD SEE SOME FLURRIES THROUGH THE
OVERNIGHT HOURS AND INTO THE DAY ON MONDAY. SNOW ACCUMULATIONS OF 4
TO 7 INCHES ARE EXPECTED ACROSS THE FORECAST AREA WITH THIS WINTER
STORM...WITH HIGHER AMOUNTS POSSIBLE IN AREAS WHERE ANY HEAVIER
BANDS OF SNOW DEVELOP. AS A RESULT...HAVE DECIDED TO EXTEND THE
WINTER STORM WARNING TO COVER THE ENTIRE FORECAST AREA.
BY MONDAY...THE UPPER LOW ASSOCIATED WITH THE EXITING STORM SYSTEM
WILL BE PROGRESSING EASTWARD THROUGH THE OHIO RIVER VALLEY...WITH
SURFACE HIGH PRESSURE BUILDING IN BEHIND THE SYSTEM ACROSS THE
NORTHERN AND CENTRAL PLAINS. THE COMBINATION OF NORTHWESTERLY WINDS
AND A FRESH SNOW PACK WILL KEEP TEMPERATURES COOL IN THE MID
30S...WELL BELOW THE SEASONAL NORMALS. CONDITIONS WILL STAY DRY
THROUGH THE MIDDLE OF THE WEEK AS THE REGION REMAINS UNDER THE
INFLUENCE OF SURFACE HIGH PRESSURE AND A MORE ZONAL FLOW SETS UP
ACROSS MUCH OF THE CENTRAL U.S. WITH THE SURFACE HIGH SHIFTING EAST
OF THE AREA TUESDAY NIGHT INTO WEDNESDAY...EXPECT TEMPERATURES TO
GRADUALLY MODERATE TO AROUND THE 50 DEGREE MARK BY WEDNESDAY AS
WINDS BECOME OUT OF THE SOUTH. MODELS CONTINUE TO HIGHLIGHT THE NEXT
POTENTIAL FOR PRECIPITATION BY THE END OF THE WEEK AS A SURFACE LOW
MOVES IN SOUTHWEST OF THE AREA WITH A FRONTAL BOUNDARY EXTENDING
NORTHEASTWARD INTO SOUTHEAST KANSAS. THERE IS STILL UNCERTAINTY WITH
THE PLACEMENT OF THIS BOUNDARY...ALONG WITH THE TIMING IN WHICH THIS
SYSTEM WILL MOVE INTO THE CENTRAL AND SOUTHERN PLAINS. AT THIS
TIME...THE BEST POTENTIAL FOR ANY PRECIPITATION LOOKS TO BE ACROSS
EAST CENTRAL KANSAS AND FURTHER SOUTH DURING THE THURSDAY THROUGH
FRIDAY TIMEFRAME. DESPITE A MORE EASTERLY FLOW INTO THE REGION...MAY
SEE TEMPERATURES RISING TO NEAR SEASONAL NORMALS BY THE END OF THE
WEEK...INTO THE MID/UPPER 50S. THESE MODERATING TEMPERATURES WILL
KEEP ANY PRECIPITATION IN THE FORM OF RAIN.
ACH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 1 PM CDT SUNDAY FOR
KSZ011-012-023-024-026-037>040-054>056-058-059.
WINTER STORM WARNING UNTIL 7 AM CDT SUNDAY FOR KSZ008>010-
020>022-034>036.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1146 PM CDT FRI MAR 22 2013
...UPDATE TO AVIATION...
.DISCUSSION...
20Z WATER VAPOR IMAGERY SHOWS A ELONGATED TROUGH FROM WESTERN
CANADA INTO THE NORTHERN ROCKIES WITH ENERGY DIGGING INTO ITS
BASE. AT THE SURFACE WEAK RIDGING REMAINS OVER THE NORTHERN AND
CENTRAL PLAINS WITH A COOL EASTERLY WIND.
FOR TONIGHT...LARGE SCALE FORCING FOR PRECIP LOOKS TO REMAIN TO THE
WEST ACROSS THE ROCKIES...SO THINK CHANCES FOR MEASURABLE PRECIP ARE
FAIRLY LOW. THE NAM AND RAP ARE SHOWING SOME WEAK ISENTROPIC ACCENT
DEVELOPING ON THE 280K SURFACE...SUGGESTING THERE COULD AGAIN BE
SOME PATCHY FREEZING DRIZZLE AFTER MIDNIGHT. BECAUSE OF THIS HAVE
INSERTED A SLIGHT CHANCE FOR FREEZING DRIZZLE. THINK THAT LOWS
TONIGHT SHOULD BE PRETTY SIMILAR TO THE LAST COUPLE NIGHTS GIVEN
OVERCAST SKIES AND LITTLE CHANGE TO THE AIRMASS.
FOR SATURDAY THROUGH SUNDAY...THE MAIN QUESTION IS WHETHER TO
UPGRADE TO A WARNING OR MAINTAIN THE WATCH. MODELS HAVE BEEN
CONSISTENT IN AMPLIFYING A SHORTWAVE AND MOVING IT ACROSS THE
FORECAST AREA. WITH VERY GOOD LARGE SCALE FORCING FROM THE PV
ANOMALY AND Q VECTOR CONVERGENCE...PRECIP IS EXPECTED TO BECOME
WIDESPREAD ACROSS WESTERN KS SATURDAY MORNING AND SPREAD EAST INTO
EASTERN KS BY THE AFTERNOON. THEREFORE POPS HAVE BEEN INCREASED FOR
THE FORECAST AREA SATURDAY AFTERNOON AND SATURDAY NIGHT. THE NAM AND
GFS FORECAST SOUNDINGS HAVE TRENDED WARMER WITH THE BOUNDARY LAYER
SATURDAY WITH SURFACE TEMPS IN THE UPPER 30S THROUGH THE AFTERNOON
ACROSS EAST CENTRAL KS. BECAUSE OF THIS HAVE MOVED THE RAIN/SNOW
LINE BACK NORTHWEST EXPECTING AREAS ALONG AND SOUTH OF THE TURNPIKE
TO SEE MAINLY RAIN THROUGH THE BULK OF THE DAY SATURDAY. ACROSS
NORTH CENTRAL KS...TEMPS LOOK COLD ENOUGH FOR PRECIP TO BE ALL SNOW.
AS THE UPPER WAVE PASSES TO THE EAST EARLY SATURDAY EVENING...THE
COLD AIR SHOULD FILL IN WITH PRECIP CHANGING TO SNOW DURING THE
EVENING. THERE IS SOME UNCERTAINTY IN PRECIP TYPE ACROSS EAST
CENTRAL KS FOR SATURDAY EVENING BECAUSE MODELS SHOW MID LEVEL DRY
AIR LIFTING INTO THE AREA AND DRYING OUT THE DENDRITIC GROWTH ZONE.
WITH NO ICE IN THE CLOUD...THERE COULD BE SIMPLY RAIN FALLING WITH
TEMPS IN THE MID 30S. WITH RAIN EXPECTED INITIALLY SATURDAY AND THE
POTENTIAL FOR A MIX OF PRECIP SATURDAY EVENING...HAVE KNOCKED DOWN
SNOW AMOUNTS ACROSS EAST CENTRAL KS WITH MAYBE AROUND 4 INCHES
POSSIBLE BY SUNDAY AFTERNOON. OTHERWISE IT IS NOT CLEAR WHETHER
SNOWFALL RATES WILL BE ENHANCED BY MESOSCALE FORCING OR IF IT WILL
BE DRIVEN ALL BY SYNOPTIC FORCING. THERE DOES APPEAR TO BE SOME
UPRIGHT INSTABILITY ON SATURDAY WHICH COULD INCREASE SNOWFALL RATES.
AND THE NAM HINTS AT A WEAK TROWAL SATURDAY NIGHT. HOWEVER IT ONLY
REALLY SHOWS UP AROUND 600 MB AND IS NOT VERY DEEP. CONSIDERING THE
SURFACE LOW COULD END UP OVER TN OR MS BY 12Z SUNDAY...AM NOT SURE
THE WARM CONVEYOR BELT WOULD WRAP ALL THE WAY BACK INTO EASTERN KS.
PERHAPS THE ENHANCED QPF FROM THE NAM IS A FUNCTION OF THE UPPER
LEVEL DEFORMATION FROM THE WAVE PROPAGATING EAST. SO FOR FAR
NORTHEAST AND NORTH CENTRAL KS...THE FORECAST IS STILL CALLING FOR
AROUND 5 TO 7 INCHES. HAVE DECIDED TO UPGRADE AREAS WEST OF MHK TO A
WARNING SINCE THEY SHOULD BEGIN TO BE IMPACTED BY THE STORM BY NOON
TOMORROW. SINCE PRECIP MAY END UP BEING MORE RAIN IN EAST CENTRAL KS
AND THE SNOW COULD HOLD OFF UNTIL SATURDAY EVENING...WILL KEEP THE
WATCH GOING FOR AREAS EAST OF MHK AND LET LATER SHIFTS HAVE A LOOK
AT THE NEWER GUIDANCE.
WITH MODELS ADVECTING A LITTLE MORE WARM AIR INTO EASTERN KS...HAVE
BUMPED HIGHS UP TO AROUND 40 IN THE EAST WITH HIGHS NEAR THE
FREEZING MARK ACROSS NORTH CENTRAL KS. LOWS SUNDAY MORNING SHOULD
FALL INTO THE 20S AS NORTHWEST WINDS INCREASE AND BRING COLDER AIR
SOUTH. CLOUD COVER AND BREEZY NORTHWEST WINDS SHOULD KEEP TEMPS FROM
WARMING MUCH ON SUNDAY...SO HIGHS ARE FORECAST TO BE IN THE LOWER TO
MID 30S.
WOLTERS
SUNDAY NIGHT THROUGH FRIDAY...
SECONDARY UPPER TROF SWINGS THROUGH LATE SUNDAY NIGHT AND MONDAY
WITH LIMITED FORCING AND ONLY SHALLOW MOISTURE SO WILL KEEP DRY
FORECAST GOING. NORTHWEST WINDS PERSIST WITH TEMPS OVER THE FRESH
SNOW NOT WARMING MUCH.
SURFACE RIDGE AXIS TAKES RESIDENCE MONDAY NIGHT INTO TUESDAY AS
ZONAL FLOW BEGINS TO TAKE HOLD OF THE SOUTHWESTERN THIRD OF THE
CONUS. SOUTH WINDS KICK IN FOR AT LEAST THE BULK OF THE AREA
WEDNESDAY FOR A MORE SIGNIFICANT WARM-UP...THOUGH MODELS DIVERGE
SOMEWHAT WITH SHORTWAVES COMING SOUTHEAST ACROSS THE NORTHERN PLAINS
AND GREAT LAKES...WHICH COULD LEAVE A MODIFIED BOUNDARY OVER THE
CENTRAL PLAINS. INCREASING LOW LEVEL MOISTURE VIA THE SOUTH WINDS
COMBINED WITH THE CONVERGENCE COULD BE ENOUGH FOR SOME CHANCE FOR
MAINLY RAIN FOR THE LATTER PERIODS. THOUGH CONFIDENCE IS NOT HIGH
GIVEN EASTERLY LOW LEVEL FLOW POTENTIAL...WILL BRING TEMPS UP TO
NEAR LATE MARCH NORMALS.
65
&&
.AVIATION...
LOW PRESSURE OVER SOUTHEAST CO WILL MOVE SOUTHEAST AND THEN EAST
OVERNIGHT AND SATURDAY. AS IT DOES SO...AN AREA OF RAIN AND SNOW
WILL MOVE INTO THE TAF SITES LATE SATURDAY MORNING OR EARLY
AFTERNOON. MHK SHOULD BE MOSTLY SNOW WITH IFR AND LOWER CONDITIONS
EXPECTED THROUGHOUT MUCH OF THE DAY. TOP AND FOE MAY BEGIN AS RAIN
AND CHANGE OVER TO SNOW DURING THE AFTERNOON. FOE AND TOP SHOULD
BE IFR AND BELOW FROM ABOUT NOON ONWWARD.
60
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM SATURDAY AFTERNOON THROUGH SUNDAY
MORNING FOR KSZ011-012-023-024-026-037>040-054>056-058-059.
WINTER STORM WARNING FROM 7 AM SATURDAY TO 7 AM CDT SUNDAY FOR
KSZ008>010-020>022-034>036.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
945 PM EDT SUN MAR 24 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK ACROSS THE OHIO VALLEY OVERNIGHT. A SECOND
AREA OF LOW PRESSURE WILL MOVE NORTHEAST ALONG THE CAROLINA COAST
TONIGHT...THEN INTENSIFY AS IT TRACKS NORTH ALONG THE MID ATLANTIC
COAST MONDAY AND MONDAY NIGHT. HIGH PRESSURE BUILDS INTO THE AREA
FOR THE MID WEEK PERIOD.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
QUITE THE SN BURST ACRS CNTRL/ERN PORTIONS OF THE FA THIS EVE.
AREA OF MDT/STRONG MID LVL FRONTOGENESIS SHIFTING OFF THE ERN SHR
ATTM...AND THE PCPN CONTG TO DIMINISH IN COVERAGE/INTENSITY AS IT
DOES SO. SFC LO PRES INVOF NC CST...W/ SECOND AREA OF LO PRES IN
ERN KY. ATTENTION TURNS TO THE W WHERE ADDITIONAL PCPN SPREAD INTO
THE CNTRL MTNS. MVMNT OF THAT AREA IS TO THE NNE...AND WHILE THE
AREA OF LO PRES DRIFTS INTO THE MTNS OVRNGT...THE MID/UPR LVL LO
LAGS BEHIND FARTHER W. THE CSTL LO TO MOVE NNE ALG THE
CST...THOUGH NOT ACCOMPANIED BY WDSPRD PCPN.
LATEST RUC13 SUGGESTS THAT MAIN OF PCPN FM THE W PASSES BY TO THE
NW...THOUGH MAY CLIP FAR WNW CTYS AFT MDNGT. OTRW...XPCG SCT LGT
PCPN ELSW OVR THE FA. PTYPE XPCD TO BE MIX OF RA/WET SN (MAYBE A
LTL PL). ADDITIONAL SN ACCUMS WILL BE CONFINED TO NW CTYS...2" OR
LESS...ELSW...A FRESH COATING IS PSBL. ACRS XTRM SE VA INTO NE
NC...SCT -RA/-DZ PSBL (THOUGH WON`T RULE OUT PL). LLVL WEDGE RMNS
FIRMLY IN PLACE OVRNGT. TEMPS TO STAY NRLY STNRY IN THE L/M30S
MOST PLACES.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/...
LOW CONTS TO DEEPEN OFF THE COAST MONDAY. NEXT CONCERN IS FOR WRAP
ARND MSTR ACROSS NRN NECK / LWR MD ERN SHORE CNTYS AS CRITICAL
THICKNESS AND WET BULB HEIGHTS SUGGEST PCPN CHANGES OVR TO SNOW
THERE AFTR 12Z. HOWEVER...SFC TMPS WILL BE ABV FREEZING SO ALTHOUGH
IT WILL CONTINUE TO SNOW ACROSS NRN CNTYS MONDAY...NOT MUCH XPCTD TO
ACCUM SO NO HEADLINE HAS BEEN ISSUED FOR THAT AREA WITH THIS FCST
PACKAGE. LINGERING UPR LVL MSTR RESULTS IN A MORE RAIN/SNOW SHWR
REGIME MON AFTRN. HIGHS IN THE U30S NRN CNTYS TO M40S SERN CSTL
CNTYS.
EVE PCPN ENDS MON NITE. COLD U20S-M30S. ANTHR WEAK S/W PROGGED
ACROSS THE AREA TUE AFTRN. KEPT SLGHT CHC POPS HERE WITH HIGHS
IN THE M-U40S. HIGH PRS FINALLY BUILDS INTO THE RGN FOR THE MID
WEEK PRD. REMAINING CHILLY WITH LOWS TUE NITE IN THE U20S-L30S.
HIGHS WED IN THE U40S-L50S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
12Z GFS/ECMWF IN GENERAL AGREEMENT FOR THE EXTENDED PERIOD...SO
WENT WITH A COMPROMISE OF THE TWO. GOING WITH A DRY FCST ACRS THE
AREA WITH A GRADUAL WARMING TREND. HI PRES WILL GRADUALLY BLD IN
FM THE WNW WED NGT INTO SAT MORNG...THEN THE HI MOVES RIGHT OVR
THE REGION THEN OFF THE CST SAT THRU SUN. HI TEMPS WILL BE IN THE
UPR 40S TO LWR 50S THU...THEN WARM TO THE MID 50S TO LWR 60S SUN.
LOWS WILL BE IN THE UPR 20S TO MID 30S THU AND FRI MORNGS...THEN RANGE
THRU THE 30S SAT AND SUN MORNGS.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
LIGHT RAIN OR DRIZZLE OR RAIN SNOW MIX WILL CONTINUE THROUGH THE
OVERNIGHT HOURS. EXPECT ANOTHER ROUND OF MODERATE WINTRY PRECIP
BY 09Z ASSOCIATED WITH MOISTURE FROM SURFACE LOW CURRENTLY OVER
WVA/KY. FLIGHT RESTRICTIONS WILL FLUCTUATE BETWEEN LIFR AND MVFR
THOUGH 15-18Z MON EXCEPT FOR KSBY WHERE FLIGHT RESTRICTIONS WILL
LAST LONGER. EXPECT GUSTY WINDS 15-25 KT...ORF/PHF/ECG...OVERNIGHT AS
LOW PRES INTENSIFIES NEAR THE COAST.
RAIN MAY START TO MIX WITH SNOW AT RIC/SBY EARLY MONDAY MORNING...AND
ALL SITES WILL HAVE A CHC FOR SHRA OR SHRASN THROUGH THE DAY. WINDS
SHIFT TO THE NW AND STRENGTHEN WITH GUSTS TO 25-30 KT ALL SITES BY
LATE MORNING THROUGH THE AFTN. ISOLATED SHOWERS OR FLURRIES WILL
STILL BE POSSIBLE TUE...BUT VFR CONDITIONS WILL GENLY PREVAIL.
VFR/MAINLY DRY WED-THU.
&&
.MARINE...
HAVE LEFT SCA AND GALE WRNG HEADLINES IN PLACE FOR ALL THE WTRS
THRU MON EVENG...BASED ON LATEST MODEL GUIDANCE. STICKING CLS TO
THE LATEST GFS MODEL AND ITS TRACK AND INTENSIFICATION OF THE LO
PRES SYSTEM TNGT THRU MON NGT. THE LO WILL START TO INTENSIFY JUST
OFF THE VA CAPES EARLY MON MORNG...THEN CONTINUE TO STRENGTHEN AS
IT MOVES NE TWD THE NRN ATLC MON THRU MON NGT. ENE WINDS 15 TO 25
KT WITH GUSTS TO ARND 30 KT THIS EVENG/TNGT WILL SHIFT TO THE WNW
LATE MON MORNG INTO MON AFTN. GUSTS TO ARND 35 KT WILL OCCUR OVR
THE CSTL WTRS MON INTO MON EVENG. SEAS WILL BUILD TO 6-9 FT NORTH
DURING MON AND 5-7 FT SOUTH THIS EVENING/TNGT. GRADIENT WEAKENS
LATER MON NIGHT/EARLY TUE...SO HAVE ENDED HEADLINES BY MIDNIGHT
(ALTHOUGH WILL LIKELY NEED TO THEN ISSUE SCA`S FOR THE COASTAL
WATERS FOR LINGERING 5 FT SEAS). OTHERWISE...SUB-SCA CONDITIONS
LIKELY ON TUE...WITH ANOTHER ROUND OF HEADLINES PROBABLY NEEDED
WED-THU...AS HIGH PRESSURE BUILDS IN FROM THE WEST...WHILE LOW
PRESSURE REMAINS OFF THE CANADIAN MARITIMES.
&&
.TIDES/COASTAL FLOODING...
LATEST MDL GUIDANCE SHOWING POTENTIAL FOR MINOR FLOODING AT OCEAN
CITY BY MON EVENG/EARLY TUE MORNG. CONFIDENCE IS LOW HOWEVER...AS
WINDS WOULD BE OFFSHORE/NW BY THAT TIMEFRAME AND NOT SURE HOW WELL
THE MODEL IS HANDLING THE SITUATION. FARTHER SOUTH MDL KEEPS WATER
LEVELS BELOW FLOOD THRESHOLDS. IF WINDS ARE A LITTLE STRONGER THAN
FORECAST...THIS COULD BE UNDERDONE AND MINOR FLOODING WOULD BE
POSSIBLE AT SEWELLS PT WITH MON MORNG HIGH TIDE. EITHER WAY...THIS
SYSTEM LOOKS TO BE TOO FAST MOVING FOR MODERATE OR MAJOR FLOODING
SO NO CSTL WATCH WILL BE ISSUED AT THIS TIME. WILL CONTINUE TO
MONITOR.
&&
.CLIMATE...
LATE MARCH/EARLY APRIL SNOWFALL AT RICHMOND VA (3.5" OR GREATER)
APRIL 3 1915 - 10"
MARCH 26 1971 - 8.4"
MARCH 20 1914 - 7.8"
MARCH 30-APRIL 1 1964 - 7.2"
MARCH 27-28 1947 - 6.9"
MARCH 24-25 1906 - 6.4"
MARCH 21-22 1943 - 4.6"
MARCH 25-26 1900 - 4.5"
MARCH 24 2013 - 3.8" **** UNOFFICIAL THROUGH 00Z/25
MARCH 22 1914 - 3.6"
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...WINTER WEATHER ADVISORY UNTIL 2 PM EDT MONDAY FOR VAZ048-049.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT MONDAY NIGHT FOR
ANZ630>638.
SMALL CRAFT ADVISORY UNTIL 10 AM EDT MONDAY FOR ANZ654-656-658.
GALE WARNING FROM 10 AM TO 9 PM EDT MONDAY FOR ANZ654-656-658.
GALE WARNING FROM 4 AM TO 9 PM EDT MONDAY FOR ANZ650-652.
&&
$$
SYNOPSIS...ALB/MPR
NEAR TERM...ALB/MPR
SHORT TERM...MPR
LONG TERM...TMG
AVIATION...DAP/JEF
MARINE...TMG
TIDES/COASTAL FLOODING...AKQ
CLIMATE...ALB
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1107 AM CDT SAT MAR 23 2013
.UPDATE...
ISSUED AT 1045 AM CDT SAT MAR 23 2013
BROKEN TO OVERCAST SKY CONDITIONS TO CONTINUE THIS AFTERNOON WITH
EAST/NORTHEAST LOW LEVEL FLOW. BREAKS IN THE CLOUD COVER SHOULD
ALLOW TEMPERATURES TO RISE ABOUT TEN DEGREES WARMER THAN
YESTERDAY...WITH UPPER 40S TO LOWER 50S FOR HIGHS THIS AFTERNOON.
QUICK LOOK AT 12Z MODEL GUIDANCE CONTINUES TO INDICATE A SIGNIFICANT
WINTER STORM...WITH THE HEAVIEST SNOWFALL OF THE YEAR...OCCURRING
LATE TONIGHT AND SUNDAY. ALSO OF NOTE IS THAT BOTH THE 12Z GFS
AND NAM INITIALIZED TOO WARM AT 850MB BY AT LEAST 2 DEGREES
ACROSS THE MIDWEST. WILL LIKELY BE CONVERTING THE REMAINING WATCH
TO A WARNING EARLY THIS AFTERNOON AND ADDING ADVISORIES SOUTH OF
THIS AREA.
AS A REMINDER...EMERGENCY MANAGEMENT AND MEDIA ARE ENCOURAGED TO
ATTEND A CONFERENCE CALL SCHEDULED FOR 130 PM CDT. IF YOU DID NOT
RECEIVE NOTIFICATION...PLEASE CALL THE NATIONAL WEATHER SERVICE
OFFICE FOR DIAL IN NUMBER AND PASSCODE.
CVKING
&&
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 358 AM CDT SAT MAR 23 2013
CLOUDS WILL REMAIN IN PLACE FOR MOST OF THE DAY BASED ON BUFKIT
SOUNDINGS AND CONDENSATION PRESSURE DEFICIT PLOTS. THERE COULD BE
SOME BREAKS IN THE CLOUDS DURING THE LATE MORNING OR EARLY
AFTN...ESPECIALLY EAST OF THE MISSISSIPPI RIVER. A STRONG SHORTWAVE
WAS LOCATED OVER CENTRAL UTAH EARLY THIS MORNING PER WATER VAPOR
IMAGERY AND RAP ANALYSIS OF THE 1.5 PVU SFC. THIS FEATURE WILL DIVE
SEWD INTO THE CENTRAL AND SRN PLAINS TODAY AND PRODUCE A LATE SEASON
WINTER STORM FOR PARTS OF THE CENTRAL CONUS. WAA PCPN AHEAD OF THE
DVLPG LOW PRESSURE SYSTEM IS EXPECTED TO SPREAD INTO THE CWA THIS
AFTN.
KANOFSKY
&&
.LONG TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 358 AM CDT SAT MAR 23 2013
(TONIGHT - SUNDAY NIGHT)
LONGWAVE UPPER TROF OVER PLAINS WILL GRADUALLY BEGIN TRANSLATING EWD
DURING THIS TIME. A VERY COMPLEX SCENARIO WITH RESPECT TO HOW AND
WHERE SYSTEMS WILL TRACK THE NEXT 48HRS. WE BEGIN WITH UPR LOWS
OVER ERN MONTANA AND ANOTHER OVER NERN UTAH...WITH THE NERN UTAH LO
EXPECTED TO INITIALLY SLINGSHOT AROUND THE MONTANA LOW TOWARDS THE
MID MS VALLEY THRU LATE TONIGHT. HEADING INTO SUNDAY...THE MONTANA
LOW CONTINUES TO HAVE INFLUENCE AND IT APPEARS THAT WE ALMOST GET A
FUJIWHARA EFFECT GOING ON WITH THE INFLUENCE OF OUR EXPECTED SNOW
STORM TOWARDS A MORE NLY TRACK. THIS HAS BEEN OBSERVED WITH SEVERAL
MODEL RUNS NOW...SINCE EARLY IN THE WEEK...AND VERY MUCH EXPLAINS
WHY ALL THE WOBBLING IN THE TRACK OF THIS STORM SYSTEM...AND THE
TRACK IS OH SO CRUCIAL AT THIS POINT WHEN WE ARE DEALING WITH BIG
DIFFS IN THERMAL PROFILES. SPEAKING OF THE MODEL CHANGES...ALL
MODELS...AFTER TRENDING MORE S WITH THEIR TRACKS THE PAST 36HRS...
HAVE NOW DRIFTED BACK TO THE N...WITH THE GFS AND NAM ADJUSTING
THEIR TRACKS BY AS MUCH AS 100NM TO THE N...WITH THE GEM THE CLOSEST
TO THE TRACKS OF 24HRS AGO AND THE ECMWF AND EFFECTIVE CONSENSUS
TRACK...BUT STILL FARTHER N. TWO EFFECTS HERE IF THESE TRACKS
HOLD. FIRST...MAY SEE A SLIGHT DELAY ON LO LEVEL COLD AIR
INFILTRATION FOR TONIGHT AND SUNDAY MORNING...AND PROBABLY MORE
IMPORTANTLY...WE WILL START TO SEE A WARM WEDGE OF AIR ALOFT THAT
WAS NOT SEEN ON THE MODELS 24HRS AGO. THIS WARM WEDGE OF AIR SHOULD
BE MOST PREVALENT AT H850 AND WILL BE EASY TO TRACK AS A RESULT.
TAKING A BEST CONSENSUS APPROACH TO HOW FAR N THIS WARM AIR ALOFT
PUSHES...IT LOOKS LIKE IT WILL DEVELOP LATE TONIGHT...PUSH INTO THE
SERN HALF OF THE STL METRO AREA AND AREAS TO THE S AND E AND REMAIN
UNTIL IT GETS ROLLED UP LIKE A CARPET BY PASSAGE OF THE H850 AND
H700 LO CENTERS ON SUNDAY MORNING. THIS MAY BRING ABOUT SLEET AS A
P-TYPE INTO SECTIONS OF SERN MO AND SWRN IL BUT FOR NOW HAVE LEFT
OUT AND WILL DEAL WITH MORE AS A NOWCASTING ITEM TO MAINTAIN
CONSISTENCY WITH PREV FCST KNOWING THE WOBBLY NATURE OF THE STORM
TRACK.
OTHER ASPECTS OF THE FCST AS POINTED OUT IN DAY SHIFT DISCUSSION
REMAIN ON TRACK...WITH PCPN INITIALLY STARTING OUT AS RAIN CHANGING
TO SNOW LATER TONIGHT AS LO LEVEL COLD AIR FILTERS IN...IN WHAT
APPEARS NOW EVENTUALLY STALLING FOR A PERIOD LATE TONIGHT AND SUNDAY
MORNING NEAR THE I-44 CORRIDOR IN MO AND I-70 IN MO UNTIL THE SFC LO
CAN PASS THRU. BANDED SNOW AND THUNDERSNOW WITH ENHANCED RATES LOOK
LIKE A REAL POSSIBILITY...WITH MODEL CONSENSUS FOCUSING ALONG THE
I-70 CORRIDOR...FIRST IN CNTRL MO LATE TONIGHT AND SUNDAY MORNING
AND THEN EDGING EWD INTO STL METRO AREA SUNDAY MORNING AND EARLY
AFTN AND SWRN IL LATE SUNDAY MORNING AND SUNDAY AFTERNOON. EDGED UP
QPF FCSTS AS A RESULT...SOMETHING NOT DONE WITH THE PACKAGE FROM
24HRS AGO.
SNOW AMOUNTS STILL LOOK TO BE ABOUT 6 TO 9 INCHES FOR THE LION/S
SHARE OF THE WATCH AREA...RAPIDLY TAPERING OFF AS ONE HEADS S AND E
OF THE STL METRO AREA. CONFIDENCE IS HI ENOUGH WITH THERMAL
PROFILES AND QPF TO CONVERT THE NWRN HALF OF THE WATCH TO A WARNING
WITH THIS ISSUANCE...COVERING CNTRL AND NE MO AND W-CNTRL IL.
HOWEVER...WILL LEAVE WATCH AS-IS FOR STL METRO AND SWRN IL...WHERE
RECENT MODEL ADJUSTMENTS HAVE CURTAILED CONFIDENCE IN THE EVENT
SOMEWHAT AND WITH TIMING OF MUCH OF THE EVENT EFFECTIVELY CONSIGNED
TO THE THIRD FORECAST PERIOD...FEEL THIS IS SOMETHING THAT NEEDS A
SECOND LOOK BEFORE A COMMITTAL FOR THESE AREAS.
MOS NUMBERS LOOK REASONABLE FOR MIN TEMPS TONIGHT BUT HAVE UNDERCUT
MOS NUMBERS FOR MAX TEMPS ON SUNDAY WITH LITTLE TO NO RISE EXPECTED
AND PROBABLY A FALL DURING THE AFTERNOON IN SPOTS.
THIS EVENT MAY LINGER INTO SUNDAY NIGHT IF THE LO SLOWS DOWN ITS
SPEED AS THE SIGNS ARE BEGINNING TO POINT TO BUT RIGHT NOW IT LOOKS
LIKE ONLY MINIMAL ADDITIONAL ACCUMS POSSIBLE AND SO WILL KEEP THE
ENDING TIMES OF THE WATCH-WARNING THE SAME WITH THIS PACKAGE.
(MONDAY - TUESDAY)
THE UPPER LO OVER MONTANA IS EXPECTED TO OPEN UP AND SLIDE DOWN INTO
OUR AREA IN THE WAKE OF THE SNOW STORM...BUT IN THE FORM OF HEAVILY
SHEARED OUT REGIONS OF VORTICITY. CYCLONIC FLOW AT THE LO LEVELS
AND REASONABLE UPPER SUPPORT POINT TO SCT SHSN ON MONDAY WITH CHC OF
FLURRIES ON MONDAY NIGHT...NO REAL CHANGE FROM PREV FCST.
RIDGE BUILDS IN ON TUESDAY AND SHOULD SEE A DRY DAY...FINALLY. MUCH
BELOW AVERAGE TEMPS WILL DOMINATE THIS PERIOD WITH ANTICIPATED SNOW
COVER...LINGERING CLOUDS...AND A COLD AIRMASS BUILDING IN.
(WEDNESDAY - FRIDAY)
NW UPPER LEVEL FLOW AND SLOWLY EXITING SFC HI WILL BE THE MAIN STORY
THIS PERIOD. A FRONT SLOWLY EDGES INTO THE AREA BY FRIDAY AND HAVE
INTRODUCED A LO POP FOR RAIN IN PARTS OF SERN MO WHERE THE MOISTURE
SHOULD BE ENOUGH BY THAT POINT.
TES
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1045 AM CDT SAT MAR 23 2013
LOWERING AND THICKENING CEILINGS EXPECTED AS WELL ADVERTISED STORM
SYSTEM MOVES TOWARD THE REGION. SHOWERS SHOULD INCREASE FROM WEST
TO EAST LATE THIS AFTERNOON AND THIS EVENING...WITH PRECIPITATION
MIXING AND CHANGING OVER TO SNOW ALONG AND NORTH OF INTERSTATE 70
LATE THIS EVENING OR OVERNIGHT. REMAINDER OF THE AREA SHOULD THEN
SEE RAIN TRANSITION TO SNOW ON SUNDAY...WITH IT BECOMING HEAVY
DURING THE LATE MORNING AND EARLY AFTERNOON HOURS. IFR CONDITIONS
ARE ALMOST CERTAIN TO OCCUR BY TOMORROW MORNING. WIND WILL
INITIALLY BE FROM THE EAST/NORTHEAST AND THEN BACK TO THE
NORTHWEST AS LOW PRESSURE MOVES SOUTH AND EAST OF THE REGION ON
SUNDAY.
SPECIFICS FOR KSTL...
LOWERING AND THICKENING CEILINGS EXPECTED WITH SHOWERS DEVELOPING
DURING THE EVENING. SOME UNCERTAINTY REGARDING THE EXACT TIME OF
CHANGE OVER...WITH SOME OF THE MOST RECENT GUIDANCE SUGGESTING AN
EARLY CHANGEOVER THAN WHAT WAS BELIEVED EARLIER THIS MORNING. FOR
NOW HAVE BEEN CONSERVATIVE WITH A CHANGEOVER AROUND 12Z TO SNOW.
SNOW...HEAVY AT TIMES...WILL IMPACT THE AIRPORT LATE SUNDAY
MORNING AND INTO THE AFTERNOON WITH AIRPORT MINIMUMS LIKELY BEING
REACHED. SIGNIFICANT SNOW ACCUMULATION IS EXPECTED WITH THIS STORM
SYSTEM. INITIALLY WIND DIRECTION WILL BE FROM THE NORTHEAST...BUT
WILL TURN TO THE NORTHWEST AND BECOME BLUSTERY SUNDAY AFTERNOON AS
THE LOW PRESSURE CENTER PASSES TO THE SOUTHEAST.
CVKING
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY EVENING FOR
FRANKLIN MO-GASCONADE MO-JEFFERSON MO-LINCOLN MO-ST.
CHARLES MO-ST. LOUIS CITY MO-ST. LOUIS MO-WARREN MO.
WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 7 PM CDT SUNDAY
FOR AUDRAIN MO-BOONE MO-CALLAWAY MO-COLE MO-KNOX MO-LEWIS
MO-MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO-OSAGE MO-
PIKE MO-RALLS MO-SHELBY MO.
IL...WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY EVENING FOR
BOND IL-CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-JERSEY
IL-MACOUPIN IL-MADISON IL-MARION IL-MONROE IL-MONTGOMERY IL-
ST. CLAIR IL.
WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 7 PM CDT SUNDAY
FOR ADAMS IL-BROWN IL-PIKE IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
639 AM CDT SAT MAR 23 2013
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 358 AM CDT SAT MAR 23 2013
CLOUDS WILL REMAIN IN PLACE FOR MOST OF THE DAY BASED ON BUFKIT
SOUNDINGS AND CONDENSATION PRESSURE DEFICIT PLOTS. THERE COULD BE
SOME BREAKS IN THE CLOUDS DURING THE LATE MORNING OR EARLY
AFTN...ESPECIALLY EAST OF THE MISSISSIPPI RIVER. A STRONG SHORTWAVE
WAS LOCATED OVER CENTRAL UTAH EARLY THIS MORNING PER WATER VAPOR
IMAGERY AND RAP ANALYSIS OF THE 1.5 PVU SFC. THIS FEATURE WILL DIVE
SEWD INTO THE CENTRAL AND SRN PLAINS TODAY AND PRODUCE A LATE SEASON
WINTER STORM FOR PARTS OF THE CENTRAL CONUS. WAA PCPN AHEAD OF THE
DVLPG LOW PRESSURE SYSTEM IS EXPECTED TO SPREAD INTO THE CWA THIS
AFTN.
KANOFSKY
&&
.LONG TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 358 AM CDT SAT MAR 23 2013
(TONIGHT - SUNDAY NIGHT)
LONGWAVE UPPER TROF OVER PLAINS WILL GRADUALLY BEGIN TRANSLATING EWD
DURING THIS TIME. A VERY COMPLEX SCENARIO WITH RESPECT TO HOW AND
WHERE SYSTEMS WILL TRACK THE NEXT 48HRS. WE BEGIN WITH UPR LOWS
OVER ERN MONTANA AND ANOTHER OVER NERN UTAH...WITH THE NERN UTAH LO
EXPECTED TO INITIALLY SLINGSHOT AROUND THE MONTANA LOW TOWARDS THE
MID MS VALLEY THRU LATE TONIGHT. HEADING INTO SUNDAY...THE MONTANA
LOW CONTINUES TO HAVE INFLUENCE AND IT APPEARS THAT WE ALMOST GET A
FUJIWHARA EFFECT GOING ON WITH THE INFLUENCE OF OUR EXPECTED SNOW
STORM TOWARDS A MORE NLY TRACK. THIS HAS BEEN OBSERVED WITH SEVERAL
MODEL RUNS NOW...SINCE EARLY IN THE WEEK...AND VERY MUCH EXPLAINS
WHY ALL THE WOBBLING IN THE TRACK OF THIS STORM SYSTEM...AND THE
TRACK IS OH SO CRUCIAL AT THIS POINT WHEN WE ARE DEALING WITH BIG
DIFFS IN THERMAL PROFILES. SPEAKING OF THE MODEL CHANGES...ALL
MODELS...AFTER TRENDING MORE S WITH THEIR TRACKS THE PAST 36HRS...
HAVE NOW DRIFTED BACK TO THE N...WITH THE GFS AND NAM ADJUSTING
THEIR TRACKS BY AS MUCH AS 100NM TO THE N...WITH THE GEM THE CLOSEST
TO THE TRACKS OF 24HRS AGO AND THE ECMWF AND EFFECTIVE CONSENSUS
TRACK...BUT STILL FARTHER N. TWO EFFECTS HERE IF THESE TRACKS
HOLD. FIRST...MAY SEE A SLIGHT DELAY ON LO LEVEL COLD AIR
INFILTRATION FOR TONIGHT AND SUNDAY MORNING...AND PROBABLY MORE
IMPORTANTLY...WE WILL START TO SEE A WARM WEDGE OF AIR ALOFT THAT
WAS NOT SEEN ON THE MODELS 24HRS AGO. THIS WARM WEDGE OF AIR SHOULD
BE MOST PREVALENT AT H850 AND WILL BE EASY TO TRACK AS A RESULT.
TAKING A BEST CONSENSUS APPROACH TO HOW FAR N THIS WARM AIR ALOFT
PUSHES...IT LOOKS LIKE IT WILL DEVELOP LATE TONIGHT...PUSH INTO THE
SERN HALF OF THE STL METRO AREA AND AREAS TO THE S AND E AND REMAIN
UNTIL IT GETS ROLLED UP LIKE A CARPET BY PASSAGE OF THE H850 AND
H700 LO CENTERS ON SUNDAY MORNING. THIS MAY BRING ABOUT SLEET AS A
P-TYPE INTO SECTIONS OF SERN MO AND SWRN IL BUT FOR NOW HAVE LEFT
OUT AND WILL DEAL WITH MORE AS A NOWCASTING ITEM TO MAINTAIN
CONSISTENCY WITH PREV FCST KNOWING THE WOBBLY NATURE OF THE STORM
TRACK.
OTHER ASPECTS OF THE FCST AS POINTED OUT IN DAY SHIFT DISCUSSION
REMAIN ON TRACK...WITH PCPN INITIALLY STARTING OUT AS RAIN CHANGING
TO SNOW LATER TONIGHT AS LO LEVEL COLD AIR FILTERS IN...IN WHAT
APPEARS NOW EVENTUALLY STALLING FOR A PERIOD LATE TONIGHT AND SUNDAY
MORNING NEAR THE I-44 CORRIDOR IN MO AND I-70 IN MO UNTIL THE SFC LO
CAN PASS THRU. BANDED SNOW AND THUNDERSNOW WITH ENHANCED RATES LOOK
LIKE A REAL POSSIBILITY...WITH MODEL CONSENSUS FOCUSING ALONG THE
I-70 CORRIDOR...FIRST IN CNTRL MO LATE TONIGHT AND SUNDAY MORNING
AND THEN EDGING EWD INTO STL METRO AREA SUNDAY MORNING AND EARLY
AFTN AND SWRN IL LATE SUNDAY MORNING AND SUNDAY AFTERNOON. EDGED UP
QPF FCSTS AS A RESULT...SOMETHING NOT DONE WITH THE PACKAGE FROM
24HRS AGO.
SNOW AMOUNTS STILL LOOK TO BE ABOUT 6 TO 9 INCHES FOR THE LION/S
SHARE OF THE WATCH AREA...RAPIDLY TAPERING OFF AS ONE HEADS S AND E
OF THE STL METRO AREA. CONFIDENCE IS HI ENOUGH WITH THERMAL
PROFILES AND QPF TO CONVERT THE NWRN HALF OF THE WATCH TO A WARNING
WITH THIS ISSUANCE...COVERING CNTRL AND NE MO AND W-CNTRL IL.
HOWEVER...WILL LEAVE WATCH AS-IS FOR STL METRO AND SWRN IL...WHERE
RECENT MODEL ADJUSTMENTS HAVE CURTAILED CONFIDENCE IN THE EVENT
SOMEWHAT AND WITH TIMING OF MUCH OF THE EVENT EFFECTIVELY CONSIGNED
TO THE THIRD FORECAST PERIOD...FEEL THIS IS SOMETHING THAT NEEDS A
SECOND LOOK BEFORE A COMMITTAL FOR THESE AREAS.
MOS NUMBERS LOOK REASONABLE FOR MIN TEMPS TONIGHT BUT HAVE UNDERCUT
MOS NUMBERS FOR MAX TEMPS ON SUNDAY WITH LITTLE TO NO RISE EXPECTED
AND PROBABLY A FALL DURING THE AFTERNOON IN SPOTS.
THIS EVENT MAY LINGER INTO SUNDAY NIGHT IF THE LO SLOWS DOWN ITS
SPEED AS THE SIGNS ARE BEGINNING TO POINT TO BUT RIGHT NOW IT LOOKS
LIKE ONLY MINIMAL ADDITIONAL ACCUMS POSSIBLE AND SO WILL KEEP THE
ENDING TIMES OF THE WATCH-WARNING THE SAME WITH THIS PACKAGE.
(MONDAY - TUESDAY)
THE UPPER LO OVER MONTANA IS EXPECTED TO OPEN UP AND SLIDE DOWN INTO
OUR AREA IN THE WAKE OF THE SNOW STORM...BUT IN THE FORM OF HEAVILY
SHEARED OUT REGIONS OF VORTICITY. CYCLONIC FLOW AT THE LO LEVELS
AND REASONABLE UPPER SUPPORT POINT TO SCT SHSN ON MONDAY WITH CHC OF
FLURRIES ON MONDAY NIGHT...NO REAL CHANGE FROM PREV FCST.
RIDGE BUILDS IN ON TUESDAY AND SHOULD SEE A DRY DAY...FINALLY. MUCH
BELOW AVERAGE TEMPS WILL DOMINATE THIS PERIOD WITH ANTICIPATED SNOW
COVER...LINGERING CLOUDS...AND A COLD AIRMASS BUILDING IN.
(WEDNESDAY - FRIDAY)
NW UPPER LEVEL FLOW AND SLOWLY EXITING SFC HI WILL BE THE MAIN STORY
THIS PERIOD. A FRONT SLOWLY EDGES INTO THE AREA BY FRIDAY AND HAVE
INTRODUCED A LO POP FOR RAIN IN PARTS OF SERN MO WHERE THE MOISTURE
SHOULD BE ENOUGH BY THAT POINT.
TES
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 610 AM CDT SAT MAR 23 2013
INITIALLY VFR TO MVFR CONDITIONS WILL DETERIORATE TO IFR LATER
TONIGHT ONCE A LATE SEASON WINTER STORM STARTS TO AFFECT THE
TERMINALS. PRECIPITATION WILL BEGIN AS RAIN DURING THE LATE AFTN
/KCOU/ AND EARLY EVENING /KCPS...KSUS...AND KUIN/ THEN TRANSITION
TO SNOW OVERNIGHT. THE HEAVIEST SNOWFALL AND THE GREATEST DURATION
ARE EXPECTED TO OCCUR AT KUIN AND KCOU. SNOW WILL TAPER TO
FLURRIES BEYOND THE END OF THE VALID TAF PD. AROUND 6 TO 8 INCHES
OF SNOW IS EXPECTED AT KCOU AND KUIN. AROUND 5 TO 7 INCHES OF SNOW
WILL BE POSSIBLE AT KSUS/KCPS UNLESS THE SYSTEM TAKES A MORE
NORTHERN TRACK WHICH WOULD PRODUCE LESS SNOW AT METRO AREA TAF
SITES.
SPECIFICS FOR KSTL...INITIALLY VFR CONDITIONS WILL DETERIORATE TO
IFR LATER TONIGHT ONCE A LATE SEASON WINTER STORM STARTS TO AFFECT
KSTL. PRECIPITATION WILL BEGIN AS RAIN EARLY THIS EVENING THEN
TRANSITION TO SNOW EARLY TOMORROW MORNING. SNOW WILL TAPER TO
FLURRIES BEYOND THE END OF THE VALID TAF PD. AROUND 5-7 INCHES OF
SNOW WILL BE POSSIBLE UNLESS THE SYSTEM TAKES A MORE NORTHERN
TRACK WHICH WOULD PRODUCE LESS SNOW AT KSTL.
KANOFSKY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY EVENING FOR
FRANKLIN MO-GASCONADE MO-JEFFERSON MO-LINCOLN MO-ST.
CHARLES MO-ST. LOUIS CITY MO-ST. LOUIS MO-WARREN MO.
WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 7 PM CDT SUNDAY
FOR AUDRAIN MO-BOONE MO-CALLAWAY MO-COLE MO-KNOX MO-LEWIS
MO-MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO-OSAGE MO-
PIKE MO-RALLS MO-SHELBY MO.
IL...WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY EVENING FOR
BOND IL-CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-JERSEY
IL-MACOUPIN IL-MADISON IL-MARION IL-MONROE IL-MONTGOMERY IL-
ST. CLAIR IL.
WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 7 PM CDT SUNDAY
FOR ADAMS IL-BROWN IL-PIKE IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
359 AM CDT SAT MAR 23 2013
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 358 AM CDT SAT MAR 23 2013
CLOUDS WILL REMAIN IN PLACE FOR MOST OF THE DAY BASED ON BUFKIT
SOUNDINGS AND CONDENSATION PRESSURE DEFICIT PLOTS. THERE COULD BE
SOME BREAKS IN THE CLOUDS DURING THE LATE MORNING OR EARLY
AFTN...ESPECIALLY EAST OF THE MISSISSIPPI RIVER. A STRONG SHORTWAVE
WAS LOCATED OVER CENTRAL UTAH EARLY THIS MORNING PER WATER VAPOR
IMAGERY AND RAP ANALYSIS OF THE 1.5 PVU SFC. THIS FEATURE WILL DIVE
SEWD INTO THE CENTRAL AND SRN PLAINS TODAY AND PRODUCE A LATE SEASON
WINTER STORM FOR PARTS OF THE CENTRAL CONUS. WAA PCPN AHEAD OF THE
DVLPG LOW PRESSURE SYSTEM IS EXPECTED TO SPREAD INTO THE CWA THIS
AFTN.
KANOFSKY
&&
.LONG TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 358 AM CDT SAT MAR 23 2013
(TONIGHT - SUNDAY NIGHT)
LONGWAVE UPPER TROF OVER PLAINS WILL GRADUALLY BEGIN TRANSLATING EWD
DURING THIS TIME. A VERY COMPLEX SCENARIO WITH RESPECT TO HOW AND
WHERE SYSTEMS WILL TRACK THE NEXT 48HRS. WE BEGIN WITH UPR LOWS
OVER ERN MONTANA AND ANOTHER OVER NERN UTAH...WITH THE NERN UTAH LO
EXPECTED TO INITIALLY SLINGSHOT AROUND THE MONTANA LOW TOWARDS THE
MID MS VALLEY THRU LATE TONIGHT. HEADING INTO SUNDAY...THE MONTANA
LOW CONTINUES TO HAVE INFLUENCE AND IT APPEARS THAT WE ALMOST GET A
FUJIWHARA EFFECT GOING ON WITH THE INFLUENCE OF OUR EXPECTED SNOW
STORM TOWARDS A MORE NLY TRACK. THIS HAS BEEN OBSERVED WITH SEVERAL
MODEL RUNS NOW...SINCE EARLY IN THE WEEK...AND VERY MUCH EXPLAINS
WHY ALL THE WOBBLING IN THE TRACK OF THIS STORM SYSTEM...AND THE
TRACK IS OH SO CRUCIAL AT THIS POINT WHEN WE ARE DEALING WITH BIG
DIFFS IN THERMAL PROFILES. SPEAKING OF THE MODEL CHANGES...ALL
MODELS...AFTER TRENDING MORE S WITH THEIR TRACKS THE PAST 36HRS...
HAVE NOW DRIFTED BACK TO THE N...WITH THE GFS AND NAM ADJUSTING
THEIR TRACKS BY AS MUCH AS 100NM TO THE N...WITH THE GEM THE CLOSEST
TO THE TRACKS OF 24HRS AGO AND THE ECMWF AND EFFECTIVE CONSENSUS
TRACK...BUT STILL FARTHER N. TWO EFFECTS HERE IF THESE TRACKS
HOLD. FIRST...MAY SEE A SLIGHT DELAY ON LO LEVEL COLD AIR
INFILTRATION FOR TONIGHT AND SUNDAY MORNING...AND PROBABLY MORE
IMPORTANTLY...WE WILL START TO SEE A WARM WEDGE OF AIR ALOFT THAT
WAS NOT SEEN ON THE MODELS 24HRS AGO. THIS WARM WEDGE OF AIR SHOULD
BE MOST PREVALENT AT H850 AND WILL BE EASY TO TRACK AS A RESULT.
TAKING A BEST CONSENSUS APPROACH TO HOW FAR N THIS WARM AIR ALOFT
PUSHES...IT LOOKS LIKE IT WILL DEVELOP LATE TONIGHT...PUSH INTO THE
SERN HALF OF THE STL METRO AREA AND AREAS TO THE S AND E AND REMAIN
UNTIL IT GETS ROLLED UP LIKE A CARPET BY PASSAGE OF THE H850 AND
H700 LO CENTERS ON SUNDAY MORNING. THIS MAY BRING ABOUT SLEET AS A
P-TYPE INTO SECTIONS OF SERN MO AND SWRN IL BUT FOR NOW HAVE LEFT
OUT AND WILL DEAL WITH MORE AS A NOWCASTING ITEM TO MAINTAIN
CONSISTENCY WITH PREV FCST KNOWING THE WOBBLY NATURE OF THE STORM
TRACK.
OTHER ASPECTS OF THE FCST AS POINTED OUT IN DAY SHIFT DISCUSSION
REMAIN ON TRACK...WITH PCPN INITIALLY STARTING OUT AS RAIN CHANGING
TO SNOW LATER TONIGHT AS LO LEVEL COLD AIR FILTERS IN...IN WHAT
APPEARS NOW EVENTUALLY STALLING FOR A PERIOD LATE TONIGHT AND SUNDAY
MORNING NEAR THE I-44 CORRIDOR IN MO AND I-70 IN MO UNTIL THE SFC LO
CAN PASS THRU. BANDED SNOW AND THUNDERSNOW WITH ENHANCED RATES LOOK
LIKE A REAL POSSIBILITY...WITH MODEL CONSENSUS FOCUSING ALONG THE
I-70 CORRIDOR...FIRST IN CNTRL MO LATE TONIGHT AND SUNDAY MORNING
AND THEN EDGING EWD INTO STL METRO AREA SUNDAY MORNING AND EARLY
AFTN AND SWRN IL LATE SUNDAY MORNING AND SUNDAY AFTERNOON. EDGED UP
QPF FCSTS AS A RESULT...SOMETHING NOT DONE WITH THE PACKAGE FROM
24HRS AGO.
SNOW AMOUNTS STILL LOOK TO BE ABOUT 6 TO 9 INCHES FOR THE LION/S
SHARE OF THE WATCH AREA...RAPIDLY TAPERING OFF AS ONE HEADS S AND E
OF THE STL METRO AREA. CONFIDENCE IS HI ENOUGH WITH THERMAL
PROFILES AND QPF TO CONVERT THE NWRN HALF OF THE WATCH TO A WARNING
WITH THIS ISSUANCE...COVERING CNTRL AND NE MO AND W-CNTRL IL.
HOWEVER...WILL LEAVE WATCH AS-IS FOR STL METRO AND SWRN IL...WHERE
RECENT MODEL ADJUSTMENTS HAVE CURTAILED CONFIDENCE IN THE EVENT
SOMEWHAT AND WITH TIMING OF MUCH OF THE EVENT EFFECTIVELY CONSIGNED
TO THE THIRD FORECAST PERIOD...FEEL THIS IS SOMETHING THAT NEEDS A
SECOND LOOK BEFORE A COMMITTAL FOR THESE AREAS.
MOS NUMBERS LOOK REASONABLE FOR MIN TEMPS TONIGHT BUT HAVE UNDERCUT
MOS NUMBERS FOR MAX TEMPS ON SUNDAY WITH LITTLE TO NO RISE EXPECTED
AND PROBABLY A FALL DURING THE AFTERNOON IN SPOTS.
THIS EVENT MAY LINGER INTO SUNDAY NIGHT IF THE LO SLOWS DOWN ITS
SPEED AS THE SIGNS ARE BEGINNING TO POINT TO BUT RIGHT NOW IT LOOKS
LIKE ONLY MINIMAL ADDITIONAL ACCUMS POSSIBLE AND SO WILL KEEP THE
ENDING TIMES OF THE WATCH-WARNING THE SAME WITH THIS PACKAGE.
(MONDAY - TUESDAY)
THE UPPER LO OVER MONTANA IS EXPECTED TO OPEN UP AND SLIDE DOWN INTO
OUR AREA IN THE WAKE OF THE SNOW STORM...BUT IN THE FORM OF HEAVILY
SHEARED OUT REGIONS OF VORTICITY. CYCLONIC FLOW AT THE LO LEVELS
AND REASONABLE UPPER SUPPORT POINT TO SCT SHSN ON MONDAY WITH CHC OF
FLURRIES ON MONDAY NIGHT...NO REAL CHANGE FROM PREV FCST.
RIDGE BUILDS IN ON TUESDAY AND SHOULD SEE A DRY DAY...FINALLY. MUCH
BELOW AVERAGE TEMPS WILL DOMINATE THIS PERIOD WITH ANTICIPATED SNOW
COVER...LINGERING CLOUDS...AND A COLD AIRMASS BUILDING IN.
(WEDNESDAY - FRIDAY)
NW UPPER LEVEL FLOW AND SLOWLY EXITING SFC HI WILL BE THE MAIN STORY
THIS PERIOD. A FRONT SLOWLY EDGES INTO THE AREA BY FRIDAY AND HAVE
INTRODUCED A LO POP FOR RAIN IN PARTS OF SERN MO WHERE THE MOISTURE
SHOULD BE ENOUGH BY THAT POINT.
TES
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1025 PM CDT FRI MAR 22 2013
WITH A SFC RIDGE OVER THE NRN PLAINS AND GREAT LAKES REGION A
GENERALLY LIGHT ELY SFC WIND CAN BE EXPECTED LATE TGT...INCREASING
TO 10-11 KTS ON SATURDAY. THE MODELS SHOW THE ELY LOW LEVEL FLOW
BRINGING SOME DRIER LOW LEVEL AIR WWD INTO UIN AND THE ST LOUIS
METRO AREA LATE TGT AND SAT. THIS WILL LIKELY KEEP THE LOWER MVFR
CLOUD CEILINGS FURTHER W-SW OF UIN AND THE ST LOUIS METRO AREA
WITH THE LOWER MVFR CEILINGS REMAINING IN THE COU AREA. RAIN
SHOULD SPREAD EWD INTO COU LATE SAT AFTN AHEAD OF THE APPROACHING
STORM SYSTEM OVER THE PLAINS. THE PRECIPITATION WILL SPREAD EWD
INTO UIN BY LATE SAT EVNG IN THE FORM OF SNOW AND INTO THE ST
LOUIS METRO AREA IN THE FORM OF RAIN. THE CLOUD CEILING WILL LOWER
SAT EVNG AS THE LOW LEVELS SATURATE...DROPPING INTO THE IFR
CATAGORY IN COU AND THE MVFR CATAGORY AT THE OTHER TAF SITES.
SPECIFICS FOR KSTL...VFR...LOW LEVEL CLOUDS AROUND 3200-4000 FT
SHOULD CONTINUE FOR STL LATE TGT...RISING SLIGHTLY IN HEIGHT LATE
SAT MRNG AND AFTN. RAIN WILL SPREAD EWD INTO STL SAT EVNG AHEAD
OF THE APPROACHING STORM SYSTEM WITH THE CLOUD CEILING DROPPING
INTO THE MVFR CATAGORY SAT EVNG AND INTO THE IFR CATAGORY LATE SAT
NGT. THE RAIN WILL LIKELY CHANGE OVER TO SNOW LATE SAT NGT WITH
VSBYS DROPPING. LIGHT ELY SFC WIND WILL INCREASE TO 10-11 KTS SAT
AFTN...THEN CONTINUE TO STRENGTHEN LATE SAT NGT AS THE SFC PRESSURE
GRADIENT TIGHTENS AS A SFC LOW DEVELOPS S OF STL.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY EVENING FOR
FRANKLIN MO-GASCONADE MO-JEFFERSON MO-LINCOLN MO-ST.
CHARLES MO-ST. LOUIS CITY MO-ST. LOUIS MO-WARREN MO.
WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 7 PM CDT SUNDAY
FOR AUDRAIN MO-BOONE MO-CALLAWAY MO-COLE MO-KNOX MO-LEWIS
MO-MARION MO-MONITEAU MO-MONROE MO-MONTGOMERY MO-OSAGE MO-
PIKE MO-RALLS MO-SHELBY MO.
IL...WINTER STORM WATCH FROM LATE TONIGHT THROUGH SUNDAY EVENING FOR
BOND IL-CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-JERSEY
IL-MACOUPIN IL-MADISON IL-MARION IL-MONROE IL-MONTGOMERY IL-
ST. CLAIR IL.
WINTER STORM WARNING FROM MIDNIGHT TONIGHT TO 7 PM CDT SUNDAY
FOR ADAMS IL-BROWN IL-PIKE IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
734 PM MDT SUN MAR 24 2013
.SHORT TERM...VALID FOR MON AND TUE...
WE UPDATED THE FORECAST IN ORDER TO REMOVE CHANCES OF EVENING SNOW
SHOWERS OVER MOST OF SOUTH CENTRAL MT...LEAVING A DRY FORECAST FOR
PLACES LIKE BILLINGS. WE DID LEAVE SOME FLURRIES IN PLACE FROM BIG
TIMBER TO RED LODGE...WHERE RADAR SHOWS SHOWS SOME WEAK RETURNS AS
OF 0130 UTC /WHICH ARE ASSOCIATED WITH A WEAKENING OROGRAPHIC BAND
OF LIGHT SNOW DOWNWIND OF THE CRAZY MOUNTAINS/. THAT ACTIVITY WILL
QUICKLY DIMINISH AFTER SUNSET. OTHERWISE...LOW-LEVEL DRYING ACROSS
SOUTHEASTERN MT IS SLOWLY BRINGING AN END TO LIGHT SNOW PRODUCTION
OUT OF THE APPARENTLY SHALLOW STRATUS DECK IN THAT AREA. WE LEFT A
CHANCE OF SNOW SHOWERS IN PLAY THROUGH 06 UTC FOR SPOTS LIKE BAKER
AND EKALAKA THOUGH.
IT WILL BE COLD AGAIN TONIGHT WITH A DRY BOUNDARY LAYER /AND CLEAR
SKIES IN MANY AREAS/ AS A SURFACE HIGH PRESSURE RIDGE SETTLES OVER
THE AREA. WE ACTUALLY DROPPED LOWS A COUPLE MORE DEGREES /ALBEIT A
BIT CAUTIOUSLY/ IN RESPECT TO RECENT LAMP AND RAP OUTPUT. SCHULTZ
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
MODELS CONTINUE TO BE IN FAIRLY GOOD AGREEMENT THROUGH THE
EXTENDED PERIOD WITH NO SIGNIFICANT WEATHER SYSTEM ON THE
HORIZON.
HIGH PRESSURE WILL CONTINUE TO BUILD ACROSS THE NORTHERN ROCKIES
WEDNESDAY AND THURSDAY BUT GET FLATTENED ON FRIDAY AS A WEAK
DISTURBANCE APPROACHES FROM THE NORTHWEST. SEVERAL AREAS OF
VORTICITY WILL BE WITHIN THIS FLOW BUT OVERALL MOISTURE AND
DYNAMICS LOOK TO BE LACKING SO WILL KEEP PRECIP CHANCES MAINLY
CONFINED TO THE MOUNTAINS AND ADJACENT FOOTHILLS AND EVEN THAT
LOOKS TO BE ONLY A CHANCE FOR SNOW SHOWERS. WEAK DISTURBANCE THAT
APPROACHES ON FRIDAY IS PROGGED TO MOVE SOUTHEAST ACROSS THE STATE
FRIDAY NIGHT INTO SATURDAY. DYNAMICS ARE NOT TOO STRONG WITH THIS
SYSTEM SO WILL CONTINUE WITH JUST A SLIGHT SHOWER CHANCE FOR THE
FORECAST AREA.
FORECAST BECOMES MORE UNCERTAIN BY NEXT WEEKEND AS AN UNSETTLED
NORTHWEST FLOW ALOFT WILL BE OVER THE FORECAST AREA BRINGING A
SLIGHT CHANCE FOR A SHOWER. AN UPPER LOW APPROACHES THE CALIFORNIA
COAST SATURDAY BUT MODELS KEEP IT STATIONARY BEFORE SHIFTING IT
EAST INTO THE FOUR CORNERS REGION ON MONDAY. GIVEN BUILDING RIDGE
MID TO LATE WEEK...HAVE WARMED TEMPERATURES A FEW MORE DEGREES FOR
MOST AREAS ACROSS THE PLAINS WITH READINGS AT OR SLIGHTLY ABOVE
NORMAL. HOOLEY
&&
.AVIATION...
AN AREA OF MVFR CEILINGS AND EVEN SOME LIGHT SNOW CONTAINING BRIEF
IFR CONDITIONS IN SOUTHEASTERN MT WILL GRADUALLY DIMINISH TONIGHT.
THAT WILL LEAVE MAINLY VFR CONDITIONS IN PLACE AFTER 06 UTC...SAVE
FOR AROUND KBHK WHERE CEILINGS MAY LAST INTO MONDAY MORNING. THERE
IS A LOW PROBABILITY OF GROUND FOG IN PLACES LIKE KBIL...KMLS...OR
KBHK...BUT CONFIDENCE IN THAT IS LOW. SCHULTZ/BORSUM
&&
.PRELIMINARY POINT TEMP/POPS...
MON TUE WED THU FRI SAT SUN
-----------------------------------------------------------
BIL 011/040 023/049 027/053 030/055 029/056 032/057 032/059
10/U 00/B 00/B 01/B 11/B 02/W 20/B
LVM 008/038 016/047 024/051 029/054 029/056 032/056 032/059
10/U 01/B 11/B 12/W 22/W 12/W 20/B
HDN 008/042 019/049 025/053 029/056 028/058 030/058 030/059
10/U 00/U 00/U 01/B 11/B 12/W 10/B
MLS 005/034 014/045 022/049 026/051 026/052 028/053 028/056
20/U 00/U 00/U 01/B 11/B 12/W 10/B
4BQ 005/033 012/046 021/050 027/053 027/055 028/055 028/058
20/U 00/U 00/U 01/B 11/B 12/W 10/U
BHK 000/025 008/039 015/042 019/042 021/045 024/046 024/052
20/B 00/U 00/U 01/B 11/B 12/W 11/B
SHR 002/034 012/044 020/049 024/051 026/054 029/055 029/055
10/U 00/U 00/U 01/B 11/B 12/W 20/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
130 PM CDT SAT MAR 23 2013
.AVIATION...
18Z TAFS FOR KOMA...KLNK AND KOFK.
CONDITIONS EXPECTED TO TREND TOWARD MVFR CIGS AND VSBYS THROUGH
00Z AS SNOW SYSTEM MOVES EAST THEN IFR OR MVFR THROUGH 12Z WITH
SNOW. WINDS PICK UP AFTER 12Z INCREASING TO 34018G26KTS BEHIND
THE FRONT.
&&
.PREV DISCUSSION... /ISSUED 318 AM CDT SAT MAR 23 2013/
DISCUSSION...
MAIN FOCUS REMAINS IN THE SHORT TERM AND DEALS THE WINTER SYSTEM
THAT WILL IMPACT OUR FORECAST AREA LATER TODAY INTO SUNDAY.
EARLY MORNING WATER VAPOR SATELLITE IMAGERY SHOWED A LARGE UPPER
TROUGH OVER/JUST EAST OF THE ROCKIES WITH SPLIT CIRCULATION
CENTERS OVER SRN SASK CANADA AND NWRN CO/NERN UT REGION. ENERGY ON
SOUTHERN END OF THIS TROUGH FORECAST TO DRIVE AN H7 LOW INTO KS
THIS AFTERNOON WITH INVERTED N END OF THIS LOW FORECAST TO MOVE
TOWARD VICINITY OF FAR SERN NEBR AND ADJACENT PARTS OF MO/IA IN
00Z-06Z PERIOD. THUS WOULD EXPECT BULK OF OUR ACCUMULATING SNOW TO
DEVELOP/MOVE ACROSS FORECAST AREA THIS EVENING BEFORE SHIFTING
TOWARD SE ZONES AFTER MIDNIGHT AS H7 LOW DROPS SE ACROSS MO.
BEFORE THEN HOW QUICKLY SNOW MOVES INTO FORECAST AREA IS
QUESTIONABLE AS SURFACE HIGH TO OUR NE CONTINUES TO FEED IN DRY
AIR AND SHORTER TERM RAP/HRRR KEPT MOST OF THE PRECIP OVER WRN
ZONES WELL INTO THIS AFTERNOON. WITH MANY TEMPS YET AS OF 08Z NEAR
FREEZING...WITH SOME ABOVE...EVEN A LITTLE RECOVERY THIS AFTN
COULD MOSTLY MELT ANY SNOW THAT FALLS ON ROADS AND COMPACT A BIT
ELSEWHERE. IF ACCUMULATING SNOW IS MINIMAL THIS AFTN OVERALL
AMOUNTS COULD END UP ON LOWER SIDE OF CURRENT FORECAST RANGE WHICH
WAS 1-2 INCHES FAR NRN ZONES AND 2-4 INCHES REST OF AREA EXCEPT
FAR SRN TIER COUNTIES OF NEBR/IA WHERE AMOUNTS WERE IN 5-6 INCH
RANGE. THUS WINTER STORM WATCH WAS CONVERTED TO AN ADVISORY ALL
ZONES AND STRETCHED A BIT NORTH TO INCLUDE ALBION/COLUMBUS/NORFOLK
AND OMAHA AREAS. SOME INDICATION THAT PRECIP BANDING COULD OCCUR
PER HRRR AND HINTED AT BY 4KM WRF THIS AFTN NERN NEBR SUPPORTED BY
NAM CROSS SECTION WHICH SHOWED SOME NEGATIVE EQUIV POTENTIAL
VORTICITY. FARTHER SE FROM LNK TO OMAHA THERE COULD BE A PERIOD
OF MODERATE SNOW THIS EVENING AS H7 LOW/TROUGH BRINGS A PERIOD OF
INCREASED LIFT IN MOIST MID LAYER DENDRITIC ZONE...WITH A BIT
HIGHER AMOUNTS CLOSER TO MID LEVEL CIRC TRACK. A WEDGE OF DRIER
AIR HINTED AT BY MODELS TO PERSIST INTO THIS EVENING FROM WCNTRL
IA COUNTIES TOWARD LNK/OMA MUST BE WATCHED AS IT COULD REALLY
LIMIT SOME SNOW AMOUNTS IF LIFT ISN/T STRONG ENOUGH TO OVER COME
IT THIS EVENING.
ALTHOUGH BULK OF SYSTEM DEPARTS DURING THE DAY SUNDAY...NRN END OF
UPPER TROUGH PIVOTS SOUTH KEEPING MUCH OF THE FORECAST AREA IN
BROAD AND COLD CYCLONIC FLOW INTO MONDAY. THUS WILL KEEP LIGHT
SNOW/FLURRIES IN FORECAST INTO MONDAY ALONG WITH MAX TEMPS ON
COOLER SIDE OF GUIDANCE SUN AND MONDAY. ON THE OTHER HAND WITH
CLOUDS PERSISTING MINS WERE KEPT ON THE WARMER SIDE OF GUIDANCE.
CLEARING BY TUE AM COULD BRING COLDEST PERIOD OF THIS FORECAST
CYCLE FOLLOWED BY SOME WARM-UP/MODERATION...ESPECIALLY BY LATE
WEEK IF GFS WOULD VERIFY. FOR NOW NO CHANGES WERE MADE FROM A
MODEL/PREV FORECAST BLEND WHICH IN GENERAL WAS A BIT WARMER THAN
THE 00Z ECMWF WOULD SUPPORT BUT COOLER THAN GFS AFTER ANY NEW
SNOW COVER MELTS.
CHERMOK
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM CDT
SUNDAY FOR NEZ090>093.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT SUNDAY FOR NEZ030>032-042-
043-050-065-078-088.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT SUNDAY FOR NEZ044-051-066-
089.
WINTER WEATHER ADVISORY UNTIL 10 AM CDT SUNDAY FOR NEZ045-052-
053-067-068.
IA...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 PM CDT
SUNDAY FOR IAZ055-069-079-080-090-091.
&&
$$
FOBERT
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1042 AM CDT SAT MAR 23 2013
...ADVERSE WX CONDITIONS CONTINUE TO UNFOLD WITH STRONGEST BANDING
CONTINUING TO EVOLVE WITHIN 25-40 MILES EITHER SIDE OF THE BORDER...
.UPDATE...
ISSUED AT 1042 AM CDT SAT MAR 23 2013
EXPANDED THE WARNING INTO WEBSTER COUNTY BASED ON A REPORT OF 2-3"
OVER THE SRN END OF THE COUNTY...AND THE FACT THAT THE HEAVIER
SNOWBAND THAT AFFECTED PARTS OF PHILLIPS/HARLAN/FRANKLIN COUNTIES
ALSO AFFECTED WEBSTER COUNTY.
FCST QPF HAS BEEN REFINED USING HIGHER RES MODELS SINCE THEIR
DETAIL PERFORMS BEST DURING THE STORM...ESPECIALLY IN AREAS NOT
RECEIVING SNOW. SOME MANUAL MODIFICATION WAS ALSO DONE WHERE WE
THOUGHT IT WAS TOO LOW.
OTHERWISE WSW HAS POSTED WITH SOME MINOR WORDING ADJUSTMENTS AND A
SLGT INCREASE IN WINDS...MAINLY TNGT.
SNOW: 5-10" ENVISIONED WITHIN 25 MILES EITHER SIDE OF KS/NEB
BORDER. ELSEWHERE GENERALLY 2-5". SNOW TOTALS HAVE BEEN
LOWERED N OF I-80.
MELTING ON CONTACT: DURING PERIODS OF LIGHTER SNOW ROADS WILL HAVE
A CHANCE TO RECOVER. THE SNOWFALL RATES WILL HAVE TO PICK UP FOR
SNOW TO ACCUMULATE ON ROADS.
SATELLITE: THE COLDEST CLOUDTOPS CONTINUE N AND W OF THE FCST
AREA. THIS SUGGESTS POTENTIAL INSTABILITY ALOFT AND IT CAN BE SEE
ON THE DDC SOUNDING.
&&
UPDATE ISSUED AT 846 AM CDT SAT MAR 23 2013
ADVISORY/WARNING CONTINUES AS POSTED AT 508 AM.
06Z MODELS DID NOT HANDLE 06Z-12Z PCPN VERY WELL ALONG THE KS-NEB
BORDER. MODELS KEPT THEIR QPF W OF THE FCST AREA. THE HRRR AND RAP
ARE VERIFYING BEST SO FAR.
INITIAL REPORTS FROM NERAIN AND CO-OP OBSERVERS ARE 1-2" NEAR THE
KS-NEB BORDER.
THIS SYSTEM IS PRIMARILY ALOFT. SO THE PLAN IS TO FOLLOW THE H7
LOW WHICH WILL TRACK E ALONG I-70 THRU 06Z. SO THE MAIN DRIVER OF
SNOWFALL WILL BE MID-LEVEL WAA/FGEN UNTIL MIDDAY THEN IT
TRANSITIONS TO DEFORMATION.
OVERALL LIFT IN THE DENDRITIC GROWTH ZONE /DGZ/ IS NOT FCST TO BE
IMPRESSIVE. THIS WILL LIMIT THE SIZE OF THE FLAKES OUTSIDE OF ANY
MESOSCALE BANDING. RAP/NAM CROSS SECTIONS ONLY SHOW POTENTIAL
CONVECTIVE INSTABILITY OVER N-CNTRL KS. OVER NEB IT/S CSI. SO WE
WILL BE WATCHING FOR BANDING AND IT/S IN THE HIGH-RES MODELS...
INCLUDING THE WRF FROM THE SD SCHOOL OF MINES AND TECH.
SOME MINOR ADJUSTMENTS WERE MADE TO TEMPS/DWPTS BASED ON CURRENT
TRENDS. MOST OF THE ADJUSTMENTS WERE TO INCREASE DWPTS TO CLOSE
THE GAP WITH TEMPS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 529 AM CDT SAT MAR 23 2013
THE MAIN CHALLENGE WILL BE DETERMINING SNOWFALL AMOUNTS FOR THE
SYSTEM MOVING THROUGH THE CENTRAL PLAINS.
THE MID-LEVEL CLOSED LOW IS LOCATED OVER NORTHWESTERN COLORADO AND
WILL CONTINUE TO MOVE EAST THIS MORNING. AS ISENTROPIC LIFT
INCREASES THIS MORNING...MORE SNOW IS EXPECTED TO DEVELOP GENERALLY
FROM WEST TO EAST. THE TREND AMONG MODELS IS FOR ALL LOCATIONS
ACROSS THE CWA TO RECEIVE SOME MEASURABLE SNOW...BUT WITH LOWER QPF
THAN PREVIOUSLY FORECAST...AND HENCE LOWER SNOW AMOUNTS. THIS IS
LARGELY DUE TO THE 700 MB CLOSED LOW NOT SHOWING MUCH
INTENSIFICATION AS IT MOVES INTO THE PLAINS...AND IN FACT...THE RAP
INDICATES POTENTIAL FILLING OF THE LOW AS IT MAKES ITS WAY INTO OUR
AREA. THE PATH OF THE LOW IS SIMILAR...TRACKING IT JUST SOUTH OF THE
CWA...SO THE GENERAL ORIENTATION OF GREATER SNOW AMOUNTS WILL
CONTINUE TO BE TO THE SOUTH/SOUTHWEST...ONLY WITH LESSER AMOUNTS.
THE LOW IS FORECAST TO GET ITS ACT TOGETHER AND DEEPEN AFTER IT
PASSES TO THE EAST OF OUR AREA. ALSO WORKING AGAINST AS MUCH
ACCUMULATION IS THE POTENTIAL FOR SOME SNOW MELT...ESPECIALLY
CONSIDERING THE SNOW MELT FROM YESTERDAY...AS WE HAD COOL AND CLOUDY
CONDITIONS. ITS GETTING A LITTLE LATE IN THE YEAR TO GET THE
ACCUMULATIONS WE MIGHT HAVE GOTTEN IN FEBRUARY. THE ONE CAVEAT IS IF
PARTICULARLY INTENSE BANDS SET UP...THEN LOCALLY HIGHER AMOUNTS
COULD OCCUR...BUT THIS WOULD BE DIFFICULT TO TELL WHERE AND IF THESE
BANDS SET UP. CONSIDERING THE OVERALL DECREASE IN SNOW AMOUNTS...I
DOWNGRADED A FEW NEBRASKA COUNTIES BORDERING KANSAS TO AN ADVISORY.
THE MOSAIC RADAR LOOP SHOWS THAT THE BULK OF SNOW TO THE
WEST/SOUTHWEST OVER EASTERN COLORADO AND NORTHWESTERN KANSAS...WITH
A BAND TRYING TO EXTEND TO THE EAST OVER OUR CWA...MAINLY OVER NORTH
CENTRAL KANSAS. THE SNOW SHOULD CONTINUE TO EXPAND EAST/NORTH TODAY
WITH AN INCREASE IN WIND SPEED AS THE PRESSURE GRADIENT INCREASES.
SNOW WILL TAPER BY THE OVERNIGHT AS THE MID-LEVEL LOW MOVES EAST.
TEMPERATURES WILL PRETTY MUCH GO NOWHERE TODAY AS COLD AIR ADVECTION
ENSUES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 529 AM CDT SAT MAR 23 2013
COMPARED TO THE SHORT TERM PERIOD DESCRIBED ABOVE...THE 6 DAY-PERIOD
FROM SUNDAY THROUGH FRIDAY DOES NOT LOOK TO FEATURE ALL THAT MUCH
ACTIVE WEATHER. THAT BEING SAID...THERE ARE AT LEAST A FEW CHANCES
FOR FLURRIES EARLY...AND THEN LATER IN THE WEEK MAYBE SOME
RAIN...ALTHOUGH CONFIDENCE IS LOW. TEMPERATURE-WISE...ALTHOUGH THIS
NOTABLE MUCH-BELOW NORMAL REGIME WILL CONTINUE THROUGH TUESDAY...THE
MID-LATE WEEK TIME FRAME CONTINUES TO TREND WARMER...AND NOW HAVE
HIGHS SOLIDLY BACK INTO THE 50S BY THURSDAY-FRIDAY.
STARTING OFF AT SUNRISE SUNDAY MORNING...THE CWA WILL JUST BE
GETTING ON THE BACK-SIDE OF THE WINTER STORM...WITH THE 00Z
NAM/GFS/ECMWF RUNS IN GOOD AGREEMENT POSITIONING THE CENTER OF THE
PRIMARY 500 MB SHORTWAVE TROUGH/VORT MAX OVER SOUTHWEST MO...AND
THEN BY SUNSET REACHING WELL EAST TO THE IL/IN BORDER AREA. AS THIS
INITIAL SHORTWAVE SLIDES OFF TO THE EAST...A SECONDARY AND WEAKER
SHORTWAVE WILL DUMB-BELL SOUTHEAST TOWARD NEBRASKA OUT OF THE
WESTERN DAKOTAS...SHEARING OUT A BIT AS IT DOES SO. ALTHOUGH THE
VAST MAJORITY...IF NOT ALL...ACCUMULATING SNOW SHOULD BE OVER BY
SUNRISE...OPTED TO LINGER SOME 20-30 POPS FOR AN ADDITIONAL FEW
TENTHS OF AN INCH ACROSS EASTERN PORTIONS OF THE CWA THROUGH THE
MORNING...AND ACKNOWLEDGING AT LEAST A SLIGHT FLURRY CHANCE
ELSEWHERE. BY THE AFTERNOON...KEPT A FLURRY MENTION GOING ACROSS
ROUGHLY THE NORTHEAST 1/2 OF THE CWA AS ANTICIPATE THERE WILL BE
PLENTY OF LOW LEVEL STRATUS HANGING AROUND IN THE FAVORABLE
DENDRITIC TEMPERATURE ZONE AROUND -10 TO -12C...BUT WITHOUT ANY
MEASURABLE POP. EVEN WITH THE MAIN SNOW EVENT GONE...SUNDAY WILL NOT
BE VERY PLEASANT BY ANY MEANS...WITH HIGH TEMPS ONLY FORECAST INTO
THE LOW 30S...ALONG WITH BRISK NORTH-NORTHWEST WINDS SUSTAINED AT
LEAST 20-25 MPH IN RESPONSE TO A HEALTHY PRESSURE GRADIENT BETWEEN
SURFACE LOW PRESSURE INTENSIFYING IN THE OH VALLEY...AND AN
EXPANSIVE HIGH BUILDING IN FROM THE NORTHWEST. THESE SUNDAY WIND
SPEEDS WERE BEEFED UP ROUGHLY 5 MPH FROM PREVIOUS FORECAST.
SUNDAY NIGHT INTO MONDAY...COLD CYCLONIC FLOW REMAIN IN PLACE OVER
THE CENTRAL PLAINS...AS THE AFOREMENTIONED TRAILING SHORTWAVE TROUGH
GRADUALLY SLIDES SOUTHEAST THROUGH THE CENTRAL PLAINS...FEEDING
TOWARD THE ENTRANCE REGION OF A STOUT UPPER LEVEL JET STRETCHED
EAST-WEST ACROSS THE SOUTHEASTERN CONUS. AS ACKNOWLEDGED BY PREVIOUS
FORECASTER...THIS IS A FAIRLY CLASSIC PATTERN FOR PERIODIC...PASSING
SNOW FLURRIES UNDER LINGERING LOW STRATUS...AND HAVE MAINTAINED A
FLURRY CHANCE ALL AREAS MONDAY...AND ADDED THIS MENTION FOR SUNDAY
NIGHT ACROSS ROUGHLY THE NORTHEAST TWO-THIRDS OF THE CWA. ALTHOUGH
NOT LIKELY...CANNOT RULE OUT A FEW SPOTS PICKING UP A VERY LIGHT
MEASURABLE DUSTING FROM THIS ACTIVITY...BUT DOESN/T LOOK WORTHY OF
ADDING SLIGHT POPS AT THIS TIME. TEMP-WISE...MONDAY LOOKS TO BE
NEARLY A REPEAT OF SUNDAY WITH HIGHS ONLY LOW 30S. ALTHOUGH STILL
BREEZY FROM THE NORTHWEST...WIND SPEEDS SHOULD BE AT LEAST A TOUCH
LOWER THAN SUNDAY WITH SUSTAINED SPEEDS MORE SO 15-20 MPH. BY MONDAY
NIGHT...THE BACK EDGE OF THE TRAILING MID LEVEL WAVE SHOULD FINALLY
DRIFT SOUTHEAST OF THE CWA...LEADING TO DECREASING CLOUDS AND ENDING
ANY FLURRY CHANCES. BREEZES WILL DROP OFF CONSIDERABLY MONDAY NIGHT
AS A RIDGE AXIS WORKS INTO THE AREA...ALTHOUGH DO NOT ANTICIPATE
IMPACTFUL FOG DEVELOPMENT AT THIS TIME.
TUESDAY/TUESDAY NIGHT...WILL MAINTAIN A DRY FORECAST FOR NOW AS FLOW
ALOFT TRANSITIONS MORE ZONAL IN RESPONSE TO A BROAD...GENERALLY
MOISTURE-STARVED SHORTWAVE TROUGH TRANSLATING TOWARD THE CENTRAL
PLAINS FROM THE NORTHERN ROCKIES. THAT BEING SAID...THE LATEST ECMWF
RUN ACTUALLY TRIES TO GENERATE SOME HIT AND MISS PRECIP TUESDAY
NIGHT...THAT IF IT WERE TO MATERIALIZE COULD TAKE THE FORM OF SNOW
OR A WINTRY MIX. HOWEVER...CONFIDENCE REMAINS LOW ENOUGH TO LEAVE
OUT FOR NOW. WITH BREEZES TURNING MORE SOUTHERLY TUESDAY...A GRADUAL
WARMING TREND IS ANTICIPATED WITH HIGHS BACK INTO THE UPPER 30S TO
NEAR 40.
WEDNESDAY/WEDNESDAY NIGHT...THE AFOREMENTIONED WEAK SHORTWAVE TROUGH
SLIDES EAST INTO THE MIDWEST...WHILE WEAK SHORTWAVE RIDGING DEVELOPS
IN ITS WAKE OVER THE CENTRAL PLAINS. IN A CONTINUATION FROM TUES
NIGHT...THE ECWMF SUGGESTS SOME LIGHT PRECIP COULD AFFECT MAINLY
EASTERN ZONES WEDNESDAY MORNING...BUT AGAIN WILL OMIT THIS
POSSIBILITY FOR NOW GIVEN LIMITED SUPPORT FROM OTHER MODELS.
ASSUMING THAT MOST LINGERING SNOW COVER IS GONE BY THEN...ANOTHER
NICE BOOST IN TEMPS IS ANTICIPATED...WITH HIGHS ON WEDNESDAY WELL
INTO THE 40S...AND MAYBE CRACKING 50 MAINLY IN KS ZONES.
THURSDAY...LOOKS LIKE FAIRLY UNEVENTFUL QUASI-ZONAL FLOW
ALOFT...WITH ANY PRECIP CHANCES FOCUSING EITHER SLIGHTLY TO OUR
SOUTH...OR WELL OFF TO THE WEST. HAVE HIGHS BACK UP INTO THE 50S IN
NEARLY ALL AREAS BY THEN.
THURSDAY NIGHT/FRIDAY...WILL CARRY SOME TOKEN 20 POPS MAINLY FOR
LIGHT RAIN ACROSS THE CWA...AS MODELS GENERATE ANOTHER ROUND OF LOW
CONFIDENCE...HIT OR MISS LOOKING PRECIPITATION IN RESPONSE TO WEAK
PERTURBATIONS PASSING THROUGH QUASI-ZONAL FLOW ALOFT...WELL
DOWNSTREAM FROM A DEEPER LONGWAVE TROUGH STARTING TO ORGANIZE NEAR
THE PACIFIC COAST. THESE PRECIP CHANCES ARE ADMITTEDLY QUITE LOW
CONFIDENCE...AND WOULD NOT BE SURPRISED IF THEY ARE DROPPED OR
DELAYED IN UPCOMING FORECASTS. WILL AIM FOR ANOTHER DAY OF
WIDESPREAD 50S FOR HIGHS FRIDAY...WHICH WOULD AT LEAST KEEP ANY
PRECIP AS RAIN.
&&
.AVIATION...(FOR THE 12Z TAF THROUGH 12Z SUNDAY MORNING)
ISSUED AT 548 AM CDT SAT MAR 23 2013
SNOW WILL BEGIN BY MID-MORNING. RADAR ALREADY PICKING UP ON SNOW
TO THE SOUTH AND EXPECT THIS TO EXPAND NORTH AND EAST. COULD GET
DOWN TO LIFR VISIBILITY AT TIMES TODAY...BUT TOO EARLY TO GET TOO
PRECISE. WIND WILL INCREASE AS THE PRESSURE GRADIENT
TIGHTENS...STARTING FROM THE NORTHEAST AND BECOMING MORE NORTH
THIS EVENING. SNOW IS STILL EXPECTED TO TAPER OFF LATE TONIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 7 AM CDT SUNDAY FOR NEZ039>041-
046>049-060>064-074>077-086-087.
WINTER STORM WARNING UNTIL 7 AM CDT SUNDAY FOR NEZ072-073-
082>085.
KS...WINTER STORM WARNING UNTIL 7 AM CDT SUNDAY FOR KSZ005>007-
017>019.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...HEINLEIN
LONG TERM...PFANNKUCH
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
846 AM CDT SAT MAR 23 2013
...LIGHT-MODERATE WINTER STORM IS AT HAND AND ADVERSE WX CONDITIONS
UNFOLDING ATTM...
.UPDATE...
ISSUED AT 846 AM CDT SAT MAR 23 2013
ADVISORY/WARNING CONTINUES AS POSTED AT 508 AM.
06Z MODELS DID NOT HANDLE 06Z-12Z PCPN VERY WELL ALONG THE KS-NEB
BORDER. MODELS KEPT THEIR QPF W OF THE FCST AREA. THE HRRR AND RAP
ARE VERIFYING BEST SO FAR.
INITIAL REPORTS FROM NERAIN AND CO-OP OBSERVERS ARE 1-2" NEAR THE
KS-NEB BORDER.
THIS SYSTEM IS PRIMARILY ALOFT. SO THE PLAN IS TO FOLLOW THE H7
LOW WHICH WILL TRACK E ALONG I-70 THRU 06Z. SO THE MAIN DRIVER OF
SNOWFALL WILL BE MID-LEVEL WAA/FGEN UNTIL MIDDAY THEN IT
TRANSITIONS TO DEFORMATION.
OVERALL LIFT IN THE DENDRITIC GROWTH ZONE /DGZ/ IS NOT FCST TO BE
IMPRESSIVE. THIS WILL LIMIT THE SIZE OF THE FLAKES OUTSIDE OF ANY
MESOSCALE BANDING. RAP/NAM CROSS SECTIONS ONLY SHOW POTENTIAL
CONVECTIVE INSTABILITY OVER N-CNTRL KS. OVER NEB IT/S CSI. SO WE
WILL BE WATCHING FOR BANDING AND IT/S IN THE HIGH-RES MODELS...
INCLUDING THE WRF FROM THE SD SCHOOL OF MINES AND TECH.
SOME MINOR ADJUSTMENTS WERE MADE TO TEMPS/DWPTS BASED ON CURRENT
TRENDS. MOST OF THE ADJUSTMENTS WERE TO INCREASE DWPTS TO CLOSE
THE GAP WITH TEMPS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 529 AM CDT SAT MAR 23 2013
THE MAIN CHALLENGE WILL BE DETERMINING SNOWFALL AMOUNTS FOR THE
SYSTEM MOVING THROUGH THE CENTRAL PLAINS.
THE MID-LEVEL CLOSED LOW IS LOCATED OVER NORTHWESTERN COLORADO AND
WILL CONTINUE TO MOVE EAST THIS MORNING. AS ISENTROPIC LIFT
INCREASES THIS MORNING...MORE SNOW IS EXPECTED TO DEVELOP GENERALLY
FROM WEST TO EAST. THE TREND AMONG MODELS IS FOR ALL LOCATIONS
ACROSS THE CWA TO RECEIVE SOME MEASURABLE SNOW...BUT WITH LOWER QPF
THAN PREVIOUSLY FORECAST...AND HENCE LOWER SNOW AMOUNTS. THIS IS
LARGELY DUE TO THE 700 MB CLOSED LOW NOT SHOWING MUCH
INTENSIFICATION AS IT MOVES INTO THE PLAINS...AND IN FACT...THE RAP
INDICATES POTENTIAL FILLING OF THE LOW AS IT MAKES ITS WAY INTO OUR
AREA. THE PATH OF THE LOW IS SIMILAR...TRACKING IT JUST SOUTH OF THE
CWA...SO THE GENERAL ORIENTATION OF GREATER SNOW AMOUNTS WILL
CONTINUE TO BE TO THE SOUTH/SOUTHWEST...ONLY WITH LESSER AMOUNTS.
THE LOW IS FORECAST TO GET ITS ACT TOGETHER AND DEEPEN AFTER IT
PASSES TO THE EAST OF OUR AREA. ALSO WORKING AGAINST AS MUCH
ACCUMULATION IS THE POTENTIAL FOR SOME SNOW MELT...ESPECIALLY
CONSIDERING THE SNOW MELT FROM YESTERDAY...AS WE HAD COOL AND CLOUDY
CONDITIONS. ITS GETTING A LITTLE LATE IN THE YEAR TO GET THE
ACCUMULATIONS WE MIGHT HAVE GOTTEN IN FEBRUARY. THE ONE CAVEAT IS IF
PARTICULARLY INTENSE BANDS SET UP...THEN LOCALLY HIGHER AMOUNTS
COULD OCCUR...BUT THIS WOULD BE DIFFICULT TO TELL WHERE AND IF THESE
BANDS SET UP. CONSIDERING THE OVERALL DECREASE IN SNOW AMOUNTS...I
DOWNGRADED A FEW NEBRASKA COUNTIES BORDERING KANSAS TO AN ADVISORY.
THE MOSAIC RADAR LOOP SHOWS THAT THE BULK OF SNOW TO THE
WEST/SOUTHWEST OVER EASTERN COLORADO AND NORTHWESTERN KANSAS...WITH
A BAND TRYING TO EXTEND TO THE EAST OVER OUR CWA...MAINLY OVER NORTH
CENTRAL KANSAS. THE SNOW SHOULD CONTINUE TO EXPAND EAST/NORTH TODAY
WITH AN INCREASE IN WIND SPEED AS THE PRESSURE GRADIENT INCREASES.
SNOW WILL TAPER BY THE OVERNIGHT AS THE MID-LEVEL LOW MOVES EAST.
TEMPERATURES WILL PRETTY MUCH GO NOWHERE TODAY AS COLD AIR ADVECTION
ENSUES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 529 AM CDT SAT MAR 23 2013
COMPARED TO THE SHORT TERM PERIOD DESCRIBED ABOVE...THE 6 DAY-PERIOD
FROM SUNDAY THROUGH FRIDAY DOES NOT LOOK TO FEATURE ALL THAT MUCH
ACTIVE WEATHER. THAT BEING SAID...THERE ARE AT LEAST A FEW CHANCES
FOR FLURRIES EARLY...AND THEN LATER IN THE WEEK MAYBE SOME
RAIN...ALTHOUGH CONFIDENCE IS LOW. TEMPERATURE-WISE...ALTHOUGH THIS
NOTABLE MUCH-BELOW NORMAL REGIME WILL CONTINUE THROUGH TUESDAY...THE
MID-LATE WEEK TIME FRAME CONTINUES TO TREND WARMER...AND NOW HAVE
HIGHS SOLIDLY BACK INTO THE 50S BY THURSDAY-FRIDAY.
STARTING OFF AT SUNRISE SUNDAY MORNING...THE CWA WILL JUST BE
GETTING ON THE BACK-SIDE OF THE WINTER STORM...WITH THE 00Z
NAM/GFS/ECMWF RUNS IN GOOD AGREEMENT POSITIONING THE CENTER OF THE
PRIMARY 500 MB SHORTWAVE TROUGH/VORT MAX OVER SOUTHWEST MO...AND
THEN BY SUNSET REACHING WELL EAST TO THE IL/IN BORDER AREA. AS THIS
INITIAL SHORTWAVE SLIDES OFF TO THE EAST...A SECONDARY AND WEAKER
SHORTWAVE WILL DUMB-BELL SOUTHEAST TOWARD NEBRASKA OUT OF THE
WESTERN DAKOTAS...SHEARING OUT A BIT AS IT DOES SO. ALTHOUGH THE
VAST MAJORITY...IF NOT ALL...ACCUMULATING SNOW SHOULD BE OVER BY
SUNRISE...OPTED TO LINGER SOME 20-30 POPS FOR AN ADDITIONAL FEW
TENTHS OF AN INCH ACROSS EASTERN PORTIONS OF THE CWA THROUGH THE
MORNING...AND ACKNOWLEDGING AT LEAST A SLIGHT FLURRY CHANCE
ELSEWHERE. BY THE AFTERNOON...KEPT A FLURRY MENTION GOING ACROSS
ROUGHLY THE NORTHEAST 1/2 OF THE CWA AS ANTICIPATE THERE WILL BE
PLENTY OF LOW LEVEL STRATUS HANGING AROUND IN THE FAVORABLE
DENDRITIC TEMPERATURE ZONE AROUND -10 TO -12C...BUT WITHOUT ANY
MEASURABLE POP. EVEN WITH THE MAIN SNOW EVENT GONE...SUNDAY WILL NOT
BE VERY PLEASANT BY ANY MEANS...WITH HIGH TEMPS ONLY FORECAST INTO
THE LOW 30S...ALONG WITH BRISK NORTH-NORTHWEST WINDS SUSTAINED AT
LEAST 20-25 MPH IN RESPONSE TO A HEALTHY PRESSURE GRADIENT BETWEEN
SURFACE LOW PRESSURE INTENSIFYING IN THE OH VALLEY...AND AN
EXPANSIVE HIGH BUILDING IN FROM THE NORTHWEST. THESE SUNDAY WIND
SPEEDS WERE BEEFED UP ROUGHLY 5 MPH FROM PREVIOUS FORECAST.
SUNDAY NIGHT INTO MONDAY...COLD CYCLONIC FLOW REMAIN IN PLACE OVER
THE CENTRAL PLAINS...AS THE AFOREMENTIONED TRAILING SHORTWAVE TROUGH
GRADUALLY SLIDES SOUTHEAST THROUGH THE CENTRAL PLAINS...FEEDING
TOWARD THE ENTRANCE REGION OF A STOUT UPPER LEVEL JET STRETCHED
EAST-WEST ACROSS THE SOUTHEASTERN CONUS. AS ACKNOWLEDGED BY PREVIOUS
FORECASTER...THIS IS A FAIRLY CLASSIC PATTERN FOR PERIODIC...PASSING
SNOW FLURRIES UNDER LINGERING LOW STRATUS...AND HAVE MAINTAINED A
FLURRY CHANCE ALL AREAS MONDAY...AND ADDED THIS MENTION FOR SUNDAY
NIGHT ACROSS ROUGHLY THE NORTHEAST TWO-THIRDS OF THE CWA. ALTHOUGH
NOT LIKELY...CANNOT RULE OUT A FEW SPOTS PICKING UP A VERY LIGHT
MEASURABLE DUSTING FROM THIS ACTIVITY...BUT DOESN/T LOOK WORTHY OF
ADDING SLIGHT POPS AT THIS TIME. TEMP-WISE...MONDAY LOOKS TO BE
NEARLY A REPEAT OF SUNDAY WITH HIGHS ONLY LOW 30S. ALTHOUGH STILL
BREEZY FROM THE NORTHWEST...WIND SPEEDS SHOULD BE AT LEAST A TOUCH
LOWER THAN SUNDAY WITH SUSTAINED SPEEDS MORE SO 15-20 MPH. BY MONDAY
NIGHT...THE BACK EDGE OF THE TRAILING MID LEVEL WAVE SHOULD FINALLY
DRIFT SOUTHEAST OF THE CWA...LEADING TO DECREASING CLOUDS AND ENDING
ANY FLURRY CHANCES. BREEZES WILL DROP OFF CONSIDERABLY MONDAY NIGHT
AS A RIDGE AXIS WORKS INTO THE AREA...ALTHOUGH DO NOT ANTICIPATE
IMPACTFUL FOG DEVELOPMENT AT THIS TIME.
TUESDAY/TUESDAY NIGHT...WILL MAINTAIN A DRY FORECAST FOR NOW AS FLOW
ALOFT TRANSITIONS MORE ZONAL IN RESPONSE TO A BROAD...GENERALLY
MOISTURE-STARVED SHORTWAVE TROUGH TRANSLATING TOWARD THE CENTRAL
PLAINS FROM THE NORTHERN ROCKIES. THAT BEING SAID...THE LATEST ECMWF
RUN ACTUALLY TRIES TO GENERATE SOME HIT AND MISS PRECIP TUESDAY
NIGHT...THAT IF IT WERE TO MATERIALIZE COULD TAKE THE FORM OF SNOW
OR A WINTRY MIX. HOWEVER...CONFIDENCE REMAINS LOW ENOUGH TO LEAVE
OUT FOR NOW. WITH BREEZES TURNING MORE SOUTHERLY TUESDAY...A GRADUAL
WARMING TREND IS ANTICIPATED WITH HIGHS BACK INTO THE UPPER 30S TO
NEAR 40.
WEDNESDAY/WEDNESDAY NIGHT...THE AFOREMENTIONED WEAK SHORTWAVE TROUGH
SLIDES EAST INTO THE MIDWEST...WHILE WEAK SHORTWAVE RIDGING DEVELOPS
IN ITS WAKE OVER THE CENTRAL PLAINS. IN A CONTINUATION FROM TUES
NIGHT...THE ECWMF SUGGESTS SOME LIGHT PRECIP COULD AFFECT MAINLY
EASTERN ZONES WEDNESDAY MORNING...BUT AGAIN WILL OMIT THIS
POSSIBILITY FOR NOW GIVEN LIMITED SUPPORT FROM OTHER MODELS.
ASSUMING THAT MOST LINGERING SNOW COVER IS GONE BY THEN...ANOTHER
NICE BOOST IN TEMPS IS ANTICIPATED...WITH HIGHS ON WEDNESDAY WELL
INTO THE 40S...AND MAYBE CRACKING 50 MAINLY IN KS ZONES.
THURSDAY...LOOKS LIKE FAIRLY UNEVENTFUL QUASI-ZONAL FLOW
ALOFT...WITH ANY PRECIP CHANCES FOCUSING EITHER SLIGHTLY TO OUR
SOUTH...OR WELL OFF TO THE WEST. HAVE HIGHS BACK UP INTO THE 50S IN
NEARLY ALL AREAS BY THEN.
THURSDAY NIGHT/FRIDAY...WILL CARRY SOME TOKEN 20 POPS MAINLY FOR
LIGHT RAIN ACROSS THE CWA...AS MODELS GENERATE ANOTHER ROUND OF LOW
CONFIDENCE...HIT OR MISS LOOKING PRECIPITATION IN RESPONSE TO WEAK
PERTURBATIONS PASSING THROUGH QUASI-ZONAL FLOW ALOFT...WELL
DOWNSTREAM FROM A DEEPER LONGWAVE TROUGH STARTING TO ORGANIZE NEAR
THE PACIFIC COAST. THESE PRECIP CHANCES ARE ADMITTEDLY QUITE LOW
CONFIDENCE...AND WOULD NOT BE SURPRISED IF THEY ARE DROPPED OR
DELAYED IN UPCOMING FORECASTS. WILL AIM FOR ANOTHER DAY OF
WIDESPREAD 50S FOR HIGHS FRIDAY...WHICH WOULD AT LEAST KEEP ANY
PRECIP AS RAIN.
&&
.AVIATION...(FOR THE 12Z TAF THROUGH 12Z SUNDAY MORNING)
ISSUED AT 548 AM CDT SAT MAR 23 2013
SNOW WILL BEGIN BY MID-MORNING. RADAR ALREADY PICKING UP ON SNOW
TO THE SOUTH AND EXPECT THIS TO EXPAND NORTH AND EAST. COULD GET
DOWN TO LIFR VISIBILITY AT TIMES TODAY...BUT TOO EARLY TO GET TOO
PRECISE. WIND WILL INCREASE AS THE PRESSURE GRADIENT
TIGHTENS...STARTING FROM THE NORTHEAST AND BECOMING MORE NORTH
THIS EVENING. SNOW IS STILL EXPECTED TO TAPER OFF LATE TONIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY UNTIL 7 AM CDT SUNDAY FOR NEZ039>041-
046>049-060>064-074>077-085>087.
WINTER STORM WARNING UNTIL 7 AM CDT SUNDAY FOR NEZ072-073-
082>084.
KS...WINTER STORM WARNING UNTIL 7 AM CDT SUNDAY FOR KSZ005>007-
017>019.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...HEINLEIN
LONG TERM...PFANNKUCH
AVIATION...HEINLEIN
AREA FORECAST DISCUSSION...UPDATED
NWS OMAHA/VALLEY NE
647 AM CDT SAT MAR 23 2013
.UPDATE...
&&
.AVIATION...12Z TAFS FOR KOMA...KLNK AND KOFK.
AREA OF SNOW ALONG WITH MVFR/IFR CONDITIONS OVER NWRN KS/SWRN NEB
THIS MORNING BEGINNING TO GRADUALLY EXPAND EWD...AND JUST A
MATTER OF TIME NOW BEFORE REACHING TAF SITES. LOWER LEVELS WILL BE
SLOW TO SATURATE OUT OVER ERN NEB...AND DO NOT EXPECT SN ACTIVITY
TO REACH THE TERMINALS BEFORE LATE MORNING. AFTER THAT...EXPECT
MVFR/IFR COND WITH -SN WILL PREVAIL THRU THE REST OF THE FCST PD.
TOTAL ACCUMULATIONS BY SUNDAY MORNING AT KOFK UP TO 2 INCHES...AND
3 TO 5 AT KOMA/KLNK.
DEE
&&
.PREV DISCUSSION... /ISSUED 318 AM CDT SAT MAR 23 2013/
DISCUSSION...
MAIN FOCUS REMAINS IN THE SHORT TERM AND DEALS THE WINTER SYSTEM
THAT WILL IMPACT OUR FORECAST AREA LATER TODAY INTO SUNDAY.
EARLY MORNING WATER VAPOR SATELLITE IMAGERY SHOWED A LARGE UPPER
TROUGH OVER/JUST EAST OF THE ROCKIES WITH SPLIT CIRCULATION
CENTERS OVER SRN SASK CANADA AND NWRN CO/NERN UT REGION. ENERGY ON
SOUTHERN END OF THIS TROUGH FORECAST TO DRIVE AN H7 LOW INTO KS
THIS AFTERNOON WITH INVERTED N END OF THIS LOW FORECAST TO MOVE
TOWARD VICINITY OF FAR SERN NEBR AND ADJACENT PARTS OF MO/IA IN
00Z-06Z PERIOD. THUS WOULD EXPECT BULK OF OUR ACCUMULATING SNOW TO
DEVELOP/MOVE ACROSS FORECAST AREA THIS EVENING BEFORE SHIFTING
TOWARD SE ZONES AFTER MIDNIGHT AS H7 LOW DROPS SE ACROSS MO.
BEFORE THEN HOW QUICKLY SNOW MOVES INTO FORECAST AREA IS
QUESTIONABLE AS SURFACE HIGH TO OUR NE CONTINUES TO FEED IN DRY
AIR AND SHORTER TERM RAP/HRRR KEPT MOST OF THE PRECIP OVER WRN
ZONES WELL INTO THIS AFTERNOON. WITH MANY TEMPS YET AS OF 08Z NEAR
FREEZING...WITH SOME ABOVE...EVEN A LITTLE RECOVERY THIS AFTN
COULD MOSTLY MELT ANY SNOW THAT FALLS ON ROADS AND COMPACT A BIT
ELSEWHERE. IF ACCUMULATING SNOW IS MINIMAL THIS AFTN OVERALL
AMOUNTS COULD END UP ON LOWER SIDE OF CURRENT FORECAST RANGE WHICH
WAS 1-2 INCHES FAR NRN ZONES AND 2-4 INCHES REST OF AREA EXCEPT
FAR SRN TIER COUNTIES OF NEBR/IA WHERE AMOUNTS WERE IN 5-6 INCH
RANGE. THUS WINTER STORM WATCH WAS CONVERTED TO AN ADVISORY ALL
ZONES AND STRETCHED A BIT NORTH TO INCLUDE ALBION/COLUMBUS/NORFOLK
AND OMAHA AREAS. SOME INDICATION THAT PRECIP BANDING COULD OCCUR
PER HRRR AND HINTED AT BY 4KM WRF THIS AFTN NERN NEBR SUPPORTED BY
NAM CROSS SECTION WHICH SHOWED SOME NEGATIVE EQUIV POTENTIAL
VORTICITY. FARTHER SE FROM LNK TO OMAHA THERE COULD BE A PERIOD
OF MODERATE SNOW THIS EVENING AS H7 LOW/TROUGH BRINGS A PERIOD OF
INCREASED LIFT IN MOIST MID LAYER DENDRITIC ZONE...WITH A BIT
HIGHER AMOUNTS CLOSER TO MID LEVEL CIRC TRACK. A WEDGE OF DRIER
AIR HINTED AT BY MODELS TO PERSIST INTO THIS EVENING FROM WCNTRL
IA COUNTIES TOWARD LNK/OMA MUST BE WATCHED AS IT COULD REALLY
LIMIT SOME SNOW AMOUNTS IF LIFT ISN/T STRONG ENOUGH TO OVER COME
IT THIS EVENING.
ALTHOUGH BULK OF SYSTEM DEPARTS DURING THE DAY SUNDAY...NRN END OF
UPPER TROUGH PIVOTS SOUTH KEEPING MUCH OF THE FORECAST AREA IN
BROAD AND COLD CYCLONIC FLOW INTO MONDAY. THUS WILL KEEP LIGHT
SNOW/FLURRIES IN FORECAST INTO MONDAY ALONG WITH MAX TEMPS ON
COOLER SIDE OF GUIDANCE SUN AND MONDAY. ON THE OTHER HAND WITH
CLOUDS PERSISTING MINS WERE KEPT ON THE WARMER SIDE OF GUIDANCE.
CLEARING BY TUE AM COULD BRING COLDEST PERIOD OF THIS FORECAST
CYCLE FOLLOWED BY SOME WARM-UP/MODERATION...ESPECIALLY BY LATE
WEEK IF GFS WOULD VERIFY. FOR NOW NO CHANGES WERE MADE FROM A
MODEL/PREV FORECAST BLEND WHICH IN GENERAL WAS A BIT WARMER THAN
THE 00Z ECMWF WOULD SUPPORT BUT COOLER THAN GFS AFTER ANY NEW
SNOW COVER MELTS.
CHERMOK
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM CDT
SUNDAY FOR NEZ090>093.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 7 AM CDT SUNDAY FOR
NEZ030>032-042-043-050-065-078-088.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 7 AM CDT
SUNDAY FOR NEZ044-051-066-089.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 10 AM CDT
SUNDAY FOR NEZ045-052-053-067-068.
IA...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 PM CDT
SUNDAY FOR IAZ055-069-079-080-090-091.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
318 AM CDT SAT MAR 23 2013
.DISCUSSION...
MAIN FOCUS REMAINS IN THE SHORT TERM AND DEALS THE WINTER SYSTEM
THAT WILL IMPACT OUR FORECAST AREA LATER TODAY INTO SUNDAY.
EARLY MORNING WATER VAPOR SATELLITE IMAGERY SHOWED A LARGE UPPER
TROUGH OVER/JUST EAST OF THE ROCKIES WITH SPLIT CIRCULATION
CENTERS OVER SRN SASK CANADA AND NWRN CO/NERN UT REGION. ENERGY ON
SOUTHERN END OF THIS TROUGH FORECAST TO DRIVE AN H7 LOW INTO KS
THIS AFTERNOON WITH INVERTED N END OF THIS LOW FORECAST TO MOVE
TOWARD VICINITY OF FAR SERN NEBR AND ADJACENT PARTS OF MO/IA IN
00Z-06Z PERIOD. THUS WOULD EXPECT BULK OF OUR ACCUMULATING SNOW TO
DEVELOP/MOVE ACROSS FORECAST AREA THIS EVENING BEFORE SHIFTING
TOWARD SE ZONES AFTER MIDNIGHT AS H7 LOW DROPS SE ACROSS MO.
BEFORE THEN HOW QUICKLY SNOW MOVES INTO FORECAST AREA IS
QUESTIONABLE AS SURFACE HIGH TO OUR NE CONTINUES TO FEED IN DRY
AIR AND SHORTER TERM RAP/HRRR KEPT MOST OF THE PRECIP OVER WRN
ZONES WELL INTO THIS AFTERNOON. WITH MANY TEMPS YET AS OF 08Z NEAR
FREEZING...WITH SOME ABOVE...EVEN A LITTLE RECOVERY THIS AFTN
COULD MOSTLY MELT ANY SNOW THAT FALLS ON ROADS AND COMPACT A BIT
ELSEWHERE. IF ACCUMULATING SNOW IS MINIMAL THIS AFTN OVERALL
AMOUNTS COULD END UP ON LOWER SIDE OF CURRENT FORECAST RANGE WHICH
WAS 1-2 INCHES FAR NRN ZONES AND 2-4 INCHES REST OF AREA EXCEPT
FAR SRN TIER COUNTIES OF NEBR/IA WHERE AMOUNTS WERE IN 5-6 INCH
RANGE. THUS WINTER STORM WATCH WAS CONVERTED TO AN ADVISORY ALL
ZONES AND STRETCHED A BIT NORTH TO INCLUDE ALBION/COLUMBUS/NORFOLK
AND OMAHA AREAS. SOME INDICATION THAT PRECIP BANDING COULD OCCUR
PER HRRR AND HINTED AT BY 4KM WRF THIS AFTN NERN NEBR SUPPORTED BY
NAM CROSS SECTION WHICH SHOWED SOME NEGATIVE EQUIV POTENTIAL
VORTICITY. FARTHER SE FROM LNK TO OMAHA THERE COULD BE A PERIOD
OF MODERATE SNOW THIS EVENING AS H7 LOW/TROUGH BRINGS A PERIOD OF
INCREASED LIFT IN MOIST MID LAYER DENDRITIC ZONE...WITH A BIT
HIGHER AMOUNTS CLOSER TO MID LEVEL CIRC TRACK. A WEDGE OF DRIER
AIR HINTED AT BY MODELS TO PERSIST INTO THIS EVENING FROM WCNTRL
IA COUNTIES TOWARD LNK/OMA MUST BE WATCHED AS IT COULD REALLY
LIMIT SOME SNOW AMOUNTS IF LIFT ISN/T STRONG ENOUGH TO OVER COME
IT THIS EVENING.
ALTHOUGH BULK OF SYSTEM DEPARTS DURING THE DAY SUNDAY...NRN END OF
UPPER TROUGH PIVOTS SOUTH KEEPING MUCH OF THE FORECAST AREA IN
BROAD AND COLD CYCLONIC FLOW INTO MONDAY. THUS WILL KEEP LIGHT
SNOW/FLURRIES IN FORECAST INTO MONDAY ALONG WITH MAX TEMPS ON
COOLER SIDE OF GUIDANCE SUN AND MONDAY. ON THE OTHER HAND WITH
CLOUDS PERSISTING MINS WERE KEPT ON THE WARMER SIDE OF GUIDANCE.
CLEARING BY TUE AM COULD BRING COLDEST PERIOD OF THIS FORECAST
CYCLE FOLLOWED BY SOME WARM-UP/MODERATION...ESPECIALLY BY LATE
WEEK IF GFS WOULD VERIFY. FOR NOW NO CHANGES WERE MADE FROM A
MODEL/PREV FORECAST BLEND WHICH IN GENERAL WAS A BIT WARMER THAN
THE 00Z ECMWF WOULD SUPPORT BUT COOLER THAN GFS AFTER ANY NEW
SNOW COVER MELTS.
CHERMOK
&&
.AVIATION...
06Z TAFS FOR KOMA...KLNK AND KOFK.
MVFR CEILINGS WILL PROBABLY PERSIST AT KOFK/KLNK...WITH VFR
CLOUDS AT KOMA. TIMING OF SNOW AND WORSENING CONDITIONS ARE THE
PRIMARY FORECAST ISSUES LATER IN THE TAF PERIOD...WITH SNOW
DEVELOPING AT KOFK/KLNK BY 16-19Z...AND KOMA BY 20-23Z. EASTERLY
COMPONENT TO THE WINDS AND LESS THAN 12KTS EARLY IN THE
PERIOD...THEN BECOMING NORTHEAST AND INCREASING TO 12 TO 15KTS
THROUGH THE PERIOD ESPECIALLY ONCE THE SNOW BEGINS. DROPPED
VISIBILITY TO 5 MILES INITIALLY...AND THEN DOWN TO 1 1/2 MILES.
ONCE THE SNOW BEGINS...IT SHOULD CONTINUED THROUGH TO THE END OF
THE TAF PERIOD.
DEWALD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 10 AM CDT
SUNDAY FOR NEZ090>093.
WINTER WEATHER ADVISORY FROM NOON TODAY TO 7 AM CDT SUNDAY FOR
NEZ030>032-042-043-050-065-078-088.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 7 AM CDT
SUNDAY FOR NEZ044-051-066-089.
WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 10 AM CDT
SUNDAY FOR NEZ045-052-053-067-068.
IA...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 PM CDT
SUNDAY FOR IAZ055-069-079-080-090-091.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
332 AM EDT SAT MAR 23 2013
.SYNOPSIS...
A COLD NORTHWEST FLOW WILL CONTINUE TO BRING LAKE EFFECT SNOW
FLURRIES AND SNOW SHOWERS, TO CENTRAL NEW YORK TONIGHT INTO
SATURDAY... WITH JUST A FEW FLURRIES FARTHER SOUTH INTO NORTHEAST
PENNSYLVANIA. A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE AREA
ON SUNDAY, BRINGING DRY BUT CONTINUED COLD WEATHER. A STORM SYSTEM
APPROACHING FROM THE SOUTHWEST, WILL BRING A CHANCE OF SNOW LATE
SUNDAY NIGHT AND MONDAY... WITH THE BEST CHANCE BEING SOUTH OF THE
NEW YORK PENNSYLVANIA STATE LINE.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
1 AM UPDATE...
FCST WELL ON TRACK...JUST INCREASED POPS ACROSS THE NORTHERN
FINGER LAKES AND WESTERN MOHAWK VALLEY BASED ON CURRENT LOCATION
OF LAKE EFFECT SNOW BAND. REGIONS REMAINS IN BROAD CYCLONIC FLOW
ALOFT AS UPPER LOW NEAR BAFFIN BAY BEGINS RETROGRADING WESTWARD
WITH TIME THIS MORNING. UPSTREAM SFC ANALYSIS SHOWS A SFC TROUGH NOW
LOCATED ALONG THE NORTHERN LAKE ONTARIO SHORELINE AND DRIFTING
SOUTHWARD WITH TIME. THIS FEATURE SHOULD BEGIN MOVING INTO OUR
AREA LATER THIS MORNING WHICH WILL FORCE THE CURRENT LAKE EFFECT
SNOW BAND TO BEGIN DRIFTING SOUTHWARD AS FLOW BEGINS TO VEER WITH
TIME. FOR NOW...CURRENT SNOW TOTALS LOOK GOOD ALONG WITH CURRENT
HEADLINE TIMING.
10 PM UPDATE... LAKE EFFECT SNOW SHOWER ACTIVITY HAS
INCREASED INTO THE ADVISORY AREA ON SCHEDULE. CURRENT RAP SUGGESTS
BAND WILL SLOWLY SHIFT TOWARD SYRACUSE BY 1 AM, AND HOLD IN THE
SAME GENERAL VICINITY THROUGH MID MORNING. VECTOR WILL FLUCTUATE
BETWEEN 295 AND 305.
RAP CONTINUES TO SHOW GOOD LL MOISTURE PROFILE. INSTABILITY IS
MODEST, BUT THERE DOES NOT APPEAR TO BE AN INVERSION NEARBY IN THE
FIRST 700 MB.
REISSUED WSW, AND LOWERED MINS IN THE SHELTERED VALLEYS OF THE
CENTRAL SO TIER AND WESTERN CATSKILLS.
630 PM UPDATE...
VERY LIGHT SNOW SHOWERS FALLING ACROSS OUR INTERIOR COUNTIES,
WHILE WE WAIT FOR WINDS TO ALIGN AND DAYTIME THERMALS TO WEAKEN.
LES WILL INCREASE BETWEEN 8 AND 10 PM, FOCUSING THE ACTIVITY OVER
THE ADVISORY AREA.
LOWERED NEAR TERM TEMPS A BIT AS WE WERE RUNNING BELOW PLAN. GRIDS
LOOK TO BE IN GOOD SHAPE SO ONLY MINOR CHANGES.
PREV DISC...
JUST WIDESPREAD LIGHT SNOW SHOWERS AND FLURRIES ARE FALLING
ACROSS CENTRAL NY AND NORTHERN PA AS OF LATE THIS AFTERNOON.
HOWEVER EXPECT ONCE THE SUN STARTS TO GO DOWN THAT SOME HEAVIER
BANDS WILL ONCE AGAIN BE ABLE TO ORGANIZE EARLY THIS EVENING.
MODEL FORECAST SOUNDINGS CONTINUE TO INDICATE PLENTY OF MOISTURE
BELOW 700 MB AND LITTLE IF ANY CAPPING INVERSION. FLOW WILL BE
FROM 290-295 DEGREES INTO THIS EVENING WITH A SLIGHT SHIFT TOWARD
295-300 DEGREES TONIGHT. 850 MB TEMPERATURES WILL CONTINUE BETWEEN
-10 AND -12 DEGREES C WITH A 100-150 MB DEEP LAYER OF MOISTURE
WITHIN THE DENDRITIC GROWTH ZONE ACROSS CENTRAL NY. BASED ON ALL
OF THIS HAVE RE-ISSUED A LAKE EFFECT SNOW ADVISORY FOR
ONEIDA/ONONDAGA AND MADISON COUNTIES FOR TONIGHT THROUGH SATURDAY
MORNING. FARTHER SOUTH LIGHTER SNOW SHOWERS COULD BRING 1 TO 3
INCHES AS FAR SOUTH AS TOMPKINS... CHENANGO... CORTLAND AND
NORTHERN BROOME COUNTIES WITH UP TO AN INCH OR SO IN THE
CATSKILLS. OTHERWISE JUST FLURRIES ARE EXPECTED. CLOUDS WILL KEEP
TEMPERATURES FROM FALLING TOO FAR TONIGHT... BUT STILL EXPECTED TO
BE WELL BELOW NORMAL WITH LATE NIGHT READINGS MAINLY IN THE LOWER
20S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
SNOW SHOWERS WILL CONTINUE ACROSS CENTRAL NY SATURDAY MORNING...
BECOMING MORE SCATTERED BY AFTERNOON WITH INCREASED AFTERNOON
HEATING. EXPECT SOME LIGHT MULTIBANDS TO PERSIST SATURDAY NIGHT...
ALTHOUGH A CAPPING INVERSION IS FORECAST TO DEVELOP AROUND 800 MB
WITH DRYING ABOVE THE INVERSION. THIS SHOULD KEEP AMOUNTS LOWER
TOMORROW NIGHT THAN TONIGHT... ALTHOUGH AN INCH OR TWO WILL STILL
BE POSSIBLE ACROSS THE NORTHERN PART OF THE FORECAST AREA.
LINGERING FLURRIES WILL FINALLY END EARLY SUNDAY AS A HIGH
PRESSURE RIDGE BUILDS ACROSS THE AREA.
NEXT CONCERN WILL BE POTENTIAL STORM SYSTEM ON MONDAY. THE MAIN
ISSUE FOR OUR AREA WILL BE HOW FAR NORTH THE PRECIPITATION SHIELD
CAN REACH. AT THIS POINT EXPECT ANY CHANCE FOR MIXED PRECIPITATION
WILL BE LOW AS PERSISTENT BLOCKING OVER THE NORTH ATLANTIC WILL
TEND TO PUSH THE MAIN PORTION OF THIS SYSTEM TO OUR SOUTH. AT THIS
POINT ALL OF THE MODELS INDICATE A REASONABLY GOOD CHANCE FOR SOME
SNOW IN NORTHEAST PA WITH MUCH LOWER CHANCES FARTHER NORTH. THE
ECMWF HAS PROBABLY BEEN THE MOST CONSISTENT MODEL INDICATING THAT
THE NORTHERN EDGE OF THE PRECIPITATION WILL REACH THE NY/PA
BORDER. THE NAM/GFS ARE A BIT FARTHER NORTH.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
330 AM UPDATE...CURRENT EXTENDED IN GOOD SHAPE WITH NO SIGNIFICANT
CHANGES NEEDED. IN GENERAL, AN UPPER LEVEL TROF WILL REMAIN OVER THE
NORTHEAST WITH HEIGHTS GRADUALLY RISING LATE IN THE PERIOD. TEMPS
WILL REMAIN WELL BELOW NORMAL WITH SOME MODERATION LATE WEEK.
SCATTERED FLURRIES AND SNOW SHOWERS WILL PERSIST BUT NO MAJOR
STORMS ARE EXPECTED.
4 PM FRI UPDATE... MORE OF THE SAME EXPECTED THIS PD...AS HIGH LATITUDE
BLOCKING REMAINS ACRS GREENLAND...THE N ATLANTIC...AND INTO PTNS
OF NRN CANADA. AS A RESULT...UPR-LVL ENERGY WILL HAVE A TENDENCY
TO UNDERCUT THE BLOCK...WITH SLOW MOVING CLOSED SYSTEMS LIKELY
OVER PTNS OF SRN CANADA...AND THE NRN TIER OF THE CONUS. ONE SUCH
VORTEX IS PROGGED TO STAY ANCHORED FROM ONT/QUE...ACRS THE
MARITIME PROVINCES...AND INTO THE WRN ATLANTIC. THIS WILL ENSURE A
CONTINUATION OF BELOW TO WELL BELOW NORMAL HGTS/TEMPS NEXT WEEK
ACRS NY/PA.
AS FOR THE DAILY SENSIBLE WX...COLD...MOIST...AND CYCLONIC NW FLOW
SHOULD RULE...WITH SCTD SNOW SHWRS/FLRYS EACH DAY. GIVEN THE ZONAL
NATURE OF THE FLOW ACRS MOST OF THE CONUS...AND MID TO UPR-LVL
CONFLUENCE UNDERNEATH THE ABV MENTIONED SERN CANADIAN VORTEX...ANY
MAJOR STORMS SHOULD STAY WELL REMOVED TO OUR W AND S.
&&
.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
COLD NORTHWEST FLOW WILL CONTINUE THROUGH THIS TAF PERIOD BRINGING
MORE LAKE EFFECT SNOW SHOWERS AND FLURRIES. AT KRME, MVFR CIGS WILL
PERSIST THROUGH THE PERIOD WITH IFR SNOW SHOWERS POSSIBLE THROUGH
07Z WHEN THE LAKE BAND IS EXPECTED TO DROP SOUTH OF THE REGION. AT
KSYR, MVFR SNOW SHOWERS WILL CONTINUE THROUGH MID MORNING WITH
CONDITIONS OCCASIONALLY DROPPING BELOW ALT MINS THROUGH 10Z.
AFTER MID MORNING VSBYS WILL IMPROVE BUT CATEGORY WILL REMAIN MVFR
DUE TO CIGS. AT KITH/KBGM, MVFR CIGS ARE EXPECTED THROUGH THE
PERIOD WITH MVFR SNOW SHOWERS POSSIBLE BETWEEN 08Z-12Z. KELM/KAVP
WILL REMAIN VFR WITH CIGS AROUND 4K FT.
WESTERLY WINDS AROUND 10 KNOTS BECOMING NORTHWEST BY MID MORNING
AT 10-15 KNOTS AND GUSTS AROUND 25 KNOTS. WITH DECREASING TO
AROUND 10 KNOTS THIS EVENING.
.OUTLOOK...
SUN...MAINLY VFR.
SUN NGT TO MON...MVFR/IFR IN SNOW...SPCLY AT KAVP/KELM/KBGM.
TUE/WED...PSBL RESTRICTIONS IN SHSN/FLRYS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL NOON EDT TODAY FOR NYZ009-018-
036-037.
&&
$$
SYNOPSIS...MSE
NEAR TERM...CMG/DJP/MSE
SHORT TERM...MSE
LONG TERM...MLJ/RRM
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
155 AM EDT SAT MAR 23 2013
.SYNOPSIS...
A COLD NORTHWEST FLOW WILL CONTINUE TO BRING LAKE EFFECT SNOW
FLURRIES AND SNOW SHOWERS, TO CENTRAL NEW YORK TONIGHT INTO
SATURDAY... WITH JUST A FEW FLURRIES FARTHER SOUTH INTO NORTHEAST
PENNSYLVANIA. A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE AREA
ON SUNDAY, BRINGING DRY BUT CONTINUED COLD WEATHER. A STORM SYSTEM
APPROACHING FROM THE SOUTHWEST, WILL BRING A CHANCE OF SNOW LATE
SUNDAY NIGHT AND MONDAY... WITH THE BEST CHANCE BEING SOUTH OF THE
NEW YORK PENNSYLVANIA STATE LINE.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
1 AM UPDATE...
FCST WELL ON TRACK...JUST INCREASED POPS ACROSS THE NORTHERN
FINGER LAKES AND WESTERN MOHAWK VALLEY BASED ON CURRENT LOCATION
OF LAKE EFFECT SNOW BAND. REGIONS REMAINS IN BROAD CYCLONIC FLOW
ALOFT AS UPPER LOW NEAR BAFFIN BAY BEGINS RETROGRADING WESTWARD
WITH TIME THIS MORNING. UPSTREAM SFC ANALYSIS SHOWS A SFC TROUGH NOW
LOCATED ALONG THE NORTHERN LAKE ONTARIO SHORELINE AND DRIFTING
SOUTHWARD WITH TIME. THIS FEATURE SHOULD BEGIN MOVING INTO OUR
AREA LATER THIS MORNING WHICH WILL FORCE THE CURRENT LAKE EFFECT
SNOW BAND TO BEGIN DRIFTING SOUTHWARD AS FLOW BEGINS TO VEER WITH
TIME. FOR NOW...CURRENT SNOW TOTALS LOOK GOOD ALONG WITH CURRENT
HEADLINE TIMING.
10 PM UPDATE... LAKE EFFECT SNOW SHOWER ACTIVITY HAS
INCREASED INTO THE ADVISORY AREA ON SCHEDULE. CURRENT RAP SUGGESTS
BAND WILL SLOWLY SHIFT TOWARD SYRACUSE BY 1 AM, AND HOLD IN THE
SAME GENERAL VICINITY THROUGH MID MORNING. VECTOR WILL FLUCTUATE
BETWEEN 295 AND 305.
RAP CONTINUES TO SHOW GOOD LL MOISTURE PROFILE. INSTABILITY IS
MODEST, BUT THERE DOES NOT APPEAR TO BE AN INVERSION NEARBY IN THE
FIRST 700 MB.
REISSUED WSW, AND LOWERED MINS IN THE SHELTERED VALLEYS OF THE
CENTRAL SO TIER AND WESTERN CATSKILLS.
630 PM UPDATE...
VERY LIGHT SNOW SHOWERS FALLING ACROSS OUR INTERIOR COUNTIES,
WHILE WE WAIT FOR WINDS TO ALIGN AND DAYTIME THERMALS TO WEAKEN.
LES WILL INCREASE BETWEEN 8 AND 10 PM, FOCUSING THE ACTIVITY OVER
THE ADVISORY AREA.
LOWERED NEAR TERM TEMPS A BIT AS WE WERE RUNNING BELOW PLAN. GRIDS
LOOK TO BE IN GOOD SHAPE SO ONLY MINOR CHANGES.
PREV DISC...
JUST WIDESPREAD LIGHT SNOW SHOWERS AND FLURRIES ARE FALLING
ACROSS CENTRAL NY AND NORTHERN PA AS OF LATE THIS AFTERNOON.
HOWEVER EXPECT ONCE THE SUN STARTS TO GO DOWN THAT SOME HEAVIER
BANDS WILL ONCE AGAIN BE ABLE TO ORGANIZE EARLY THIS EVENING.
MODEL FORECAST SOUNDINGS CONTINUE TO INDICATE PLENTY OF MOISTURE
BELOW 700 MB AND LITTLE IF ANY CAPPING INVERSION. FLOW WILL BE
FROM 290-295 DEGREES INTO THIS EVENING WITH A SLIGHT SHIFT TOWARD
295-300 DEGREES TONIGHT. 850 MB TEMPERATURES WILL CONTINUE BETWEEN
-10 AND -12 DEGREES C WITH A 100-150 MB DEEP LAYER OF MOISTURE
WITHIN THE DENDRITIC GROWTH ZONE ACROSS CENTRAL NY. BASED ON ALL
OF THIS HAVE RE-ISSUED A LAKE EFFECT SNOW ADVISORY FOR
ONEIDA/ONONDAGA AND MADISON COUNTIES FOR TONIGHT THROUGH SATURDAY
MORNING. FARTHER SOUTH LIGHTER SNOW SHOWERS COULD BRING 1 TO 3
INCHES AS FAR SOUTH AS TOMPKINS... CHENANGO... CORTLAND AND
NORTHERN BROOME COUNTIES WITH UP TO AN INCH OR SO IN THE
CATSKILLS. OTHERWISE JUST FLURRIES ARE EXPECTED. CLOUDS WILL KEEP
TEMPERATURES FROM FALLING TOO FAR TONIGHT... BUT STILL EXPECTED TO
BE WELL BELOW NORMAL WITH LATE NIGHT READINGS MAINLY IN THE LOWER
20S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
SNOW SHOWERS WILL CONTINUE ACROSS CENTRAL NY SATURDAY MORNING...
BECOMING MORE SCATTERED BY AFTERNOON WITH INCREASED AFTERNOON
HEATING. EXPECT SOME LIGHT MULTIBANDS TO PERSIST SATURDAY NIGHT...
ALTHOUGH A CAPPING INVERSION IS FORECAST TO DEVELOP AROUND 800 MB
WITH DRYING ABOVE THE INVERSION. THIS SHOULD KEEP AMOUNTS LOWER
TOMORROW NIGHT THAN TONIGHT... ALTHOUGH AN INCH OR TWO WILL STILL
BE POSSIBLE ACROSS THE NORTHERN PART OF THE FORECAST AREA.
LINGERING FLURRIES WILL FINALLY END EARLY SUNDAY AS A HIGH
PRESSURE RIDGE BUILDS ACROSS THE AREA.
NEXT CONCERN WILL BE POTENTIAL STORM SYSTEM ON MONDAY. THE MAIN
ISSUE FOR OUR AREA WILL BE HOW FAR NORTH THE PRECIPITATION SHIELD
CAN REACH. AT THIS POINT EXPECT ANY CHANCE FOR MIXED PRECIPITATION
WILL BE LOW AS PERSISTENT BLOCKING OVER THE NORTH ATLANTIC WILL
TEND TO PUSH THE MAIN PORTION OF THIS SYSTEM TO OUR SOUTH. AT THIS
POINT ALL OF THE MODELS INDICATE A REASONABLY GOOD CHANCE FOR SOME
SNOW IN NORTHEAST PA WITH MUCH LOWER CHANCES FARTHER NORTH. THE
ECMWF HAS PROBABLY BEEN THE MOST CONSISTENT MODEL INDICATING THAT
THE NORTHERN EDGE OF THE PRECIPITATION WILL REACH THE NY/PA
BORDER. THE NAM/GFS ARE A BIT FARTHER NORTH.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
4 PM FRI UPDATE... MORE OF THE SAME EXPECTED THIS PD...AS HIGH LATITUDE
BLOCKING REMAINS ACRS GREENLAND...THE N ATLANTIC...AND INTO PTNS
OF NRN CANADA. AS A RESULT...UPR-LVL ENERGY WILL HAVE A TENDENCY
TO UNDERCUT THE BLOCK...WITH SLOW MOVING CLOSED SYSTEMS LIKELY
OVER PTNS OF SRN CANADA...AND THE NRN TIER OF THE CONUS. ONE SUCH
VORTEX IS PROGGED TO STAY ANCHORED FROM ONT/QUE...ACRS THE
MARITIME PROVINCES...AND INTO THE WRN ATLANTIC. THIS WILL ENSURE A
CONTINUATION OF BELOW TO WELL BELOW NORMAL HGTS/TEMPS NEXT WEEK
ACRS NY/PA.
AS FOR THE DAILY SENSIBLE WX...COLD...MOIST...AND CYCLONIC NW FLOW
SHOULD RULE...WITH SCTD SNOW SHWRS/FLRYS EACH DAY. GIVEN THE ZONAL
NATURE OF THE FLOW ACRS MOST OF THE CONUS...AND MID TO UPR-LVL
CONFLUENCE UNDERNEATH THE ABV MENTIONED SERN CANADIAN VORTEX...ANY
MAJOR STORMS SHOULD STAY WELL REMOVED TO OUR W AND S.
PREV DISC... 430 AM UPDATE... LITTLE CHANGE FROM EARLIER FCST
THINKING WITH MAIN ATTENTION REMAINING FOCUSED ON LATE WEEKEND AND
EARLY WORK WEEK STORM SYSTEM. HEADING INTO THE WEEKEND...A DEEP
OPEN WAVE TROUGH WILL SLOWLY DESCEND THROUGH THE CENTRAL AND
NORTHERN ROCKIES BEFORE JOINING FORCES WITH SOUTHERN STREAM
PACIFIC ENERGY LIFTING NORTHEAST THROUGH THE MEXICAN PLATEAU AND
SOUTHERN TEXAS. UPON CONSOLIDATION...SFC CYCLOGENESIS WILL OCCUR
ACROSS THE WESTERN GULF OF MEXICO. FOLLOWING THIS...BOTH SOUTHERN
AND NORTHERN STREAM SPEED MAXES WILL CONTINUE MOVING NORTHEAST
WHILE REMAINING ISOLATED FROM ONE ANOTHER WHICH WILL ALLOW FOR A
SECOND AREA OF LOW PRESSURE TO DEVELOP ACROSS THE SOUTHEAST AS
EARLY AS SUN NEAR THE FLORIDA PANHANDLE. BOTH LOWS WILL THEN
CONTINUE LIFTING NORTHEAST WITH THE FIRST LOW EVENTUALLY REACHING
THE CENTRAL APPALACHIANS WHERE IT WILL THEN TRANSFER ENERGY TO THE
NEW SOUTHERN STREAM SYSTEM WORKING UP TH EAST COAST. AS THIS
OCCURS...SNOW WILL LIFT NORTH INTO OUR AREA AS EARLY AS 06Z MONDAY
WITH THE NORTHERN EXTENT OF THE DEFORMATION BAND SNOWFALL
POTENTIALLY ONLY REACHING THE CENTRAL FINGER LAKES AS MAIN LOW
REMAINS SOUTH OF THE FCST AREA. DURING THE DAY ON MONDAY...GFS
FCST SOUNDINGS SHOW SOME DRY AIR WORKING INTO THE ICE CRYSTAL
GENERATION ZONE WHICH COMBINED WITH DAYTIME HEATING...WILL LIKELY
RESULT IN A SWITCHOVER FROM SN TO RA OR DZ. FOR NOW...HAVE NOT
ATTEMPTED TO GET TO DETERMINISTIC IN THE GRIDS AS MODEL TRENDS
CONTINUE TO EVOLVE WITH THIS FEATURE. THAT BEING SAID...EXTENDED
RANGE MODELS DO INDICATE UNSETTLED WX WILL REMAIN OVER THE REGION
AS CYCLONIC FLOW PREVAILS ALOFT. THIS SHOULD ENSURE BELOW NORMAL
TEMPS AND CONTINUED CHANCES FOR PRECIP THROUGH LATE WEEK.
130 PM UPDATE... 12Z GUIDANCE CONTS TO BE ON TRACK FOR
POTENTIAL STORM FOR EARLY NEXT WEEK. 12Z NAM/GFS IN LINE WITH 06Z
GFS REGARDING MVMT OF SYSTEM SOUTH OF THE MASON-DIXON LINE. THESE
MODELS ARE IN AGREEMENT WITH 00Z EURO THO MODELS DIFFER ON TIMING
OF QPF MVG INTO THE REGION. BASED ON MVMNT OF SYSTEM EXPECT PCPN
TO MV IN SUN NIGHT AND HV TRENDED TWD LATEST HPC GUIDANCE WITH CHC
POPS FOR THE SOUTHERN TIER AND POINTS SOUTH. MODEL TRENDS INDICATE
HIPRES WL PUMP COLD NRLY AIR DOWN FM CANADA ENUF TO KEEP PTYPE AS
ALL SNOW FOR SUN NGT INTO MON MRNG. THEN AS VLYS WARM THRU THE
AFTN, RAIN WILL START TO MIX IN DRG THE AFTN HRS. ALL GEFS MEMBERS
AGREE WITH OPERATIONAL GFS ON TRACK OF SYSTEM.
TEMPS EXPECTED TO RMN WELL BLO NORMAL THRU THE END OF THE PD WITH
HIGHS ARND 40 AND LOWS IN THE LWR-MID 20S.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
COLD NORTHWEST FLOW WILL CONTINUE THROUGH THIS TAF PERIOD BRINGING
MORE LAKE EFFECT SNOW SHOWERS AND FLURRIES. AT KRME, MVFR CIGS WILL
PERSIST THROUGH THE PERIOD WITH IFR SNOW SHOWERS POSSIBLE THROUGH
07Z WHEN THE LAKE BAND IS EXPECTED TO DROP SOUTH OF THE REGION. AT
KSYR, MVFR SNOW SHOWERS WILL CONTINUE THROUGH MID MORNING WITH
CONDITIONS OCCASIONALLY DROPPING BELOW ALT MINS THROUGH 10Z.
AFTER MID MORNING VSBYS WILL IMPROVE BUT CATEGORY WILL REMAIN MVFR
DUE TO CIGS. AT KITH/KBGM, MVFR CIGS ARE EXPECTED THROUGH THE
PERIOD WITH MVFR SNOW SHOWERS POSSIBLE BETWEEN 08Z-12Z. KELM/KAVP
WILL REMAIN VFR WITH CIGS AROUND 4K FT.
WESTERLY WINDS AROUND 10 KNOTS BECOMING NORTHWEST BY MID MORNING
AT 10-15 KNOTS AND GUSTS AROUND 25 KNOTS. WITH DECREASING TO
AROUND 10 KNOTS THIS EVENING.
.OUTLOOK...
SUN...MAINLY VFR.
SUN NGT TO MON...MVFR/IFR IN SNOW...SPCLY AT KAVP/KELM/KBGM.
TUE/WED...PSBL RESTRICTIONS IN SHSN/FLRYS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL NOON EDT TODAY FOR NYZ009-018-
036-037.
&&
$$
SYNOPSIS...MSE
NEAR TERM...CMG/DJP/MSE
SHORT TERM...MSE
LONG TERM...CMG/MLJ
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
106 AM EDT SAT MAR 23 2013
.SYNOPSIS...
A COLD NORTHWEST FLOW WILL CONTINUE TO BRING LAKE EFFECT SNOW
FLURRIES AND SNOW SHOWERS, TO CENTRAL NEW YORK TONIGHT INTO
SATURDAY... WITH JUST A FEW FLURRIES FARTHER SOUTH INTO NORTHEAST
PENNSYLVANIA. A RIDGE OF HIGH PRESSURE WILL BUILD ACROSS THE AREA
ON SUNDAY, BRINGING DRY BUT CONTINUED COLD WEATHER. A STORM SYSTEM
APPROACHING FROM THE SOUTHWEST, WILL BRING A CHANCE OF SNOW LATE
SUNDAY NIGHT AND MONDAY... WITH THE BEST CHANCE BEING SOUTH OF THE
NEW YORK PENNSYLVANIA STATE LINE.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
1 AM UPDATE...
FCST WELL ON TRACK...JUST INCREASED POPS ACROSS THE NORTHERN
FINGER LAKES AND WESTERN MOHAWK VALLEY BASED ON CURRENT LOCATION
OF LAKE EFFECT SNOW BAND. REGIONS REMAINS IN BROAD CYCLONIC FLOW
ALOFT AS UPPER LOW NEAR BAFFIN BAY BEGINS RETROGRADING WESTWARD
WITH TIME THIS MORNING. UPSTREAM SFC ANALYSIS SHOWS A SFC TROUGH NOW
LOCATED ALONG THE NORTHERN LAKE ONTARIO SHORELINE AND DRIFTING
SOUTHWARD WITH TIME. THIS FEATURE SHOULD BEGIN MOVING INTO OUR
AREA LATER THIS MORNING WHICH WILL FORCE THE CURRENT LAKE EFFECT
SNOW BAND TO BEGIN DRIFTING SOUTHWARD AS FLOW BEGINS TO VEER WITH
TIME. FOR NOW...CURRENT SNOW TOTALS LOOK GOOD ALONG WITH CURRENT
HEADLINE TIMING.
10 PM UPDATE... LAKE EFFECT SNOW SHOWER ACTIVITY HAS
INCREASED INTO THE ADVISORY AREA ON SCHEDULE. CURRENT RAP SUGGESTS
BAND WILL SLOWLY SHIFT TOWARD SYRACUSE BY 1 AM, AND HOLD IN THE
SAME GENERAL VICINITY THROUGH MID MORNING. VECTOR WILL FLUCTUATE
BETWEEN 295 AND 305.
RAP CONTINUES TO SHOW GOOD LL MOISTURE PROFILE. INSTABILITY IS
MODEST, BUT THERE DOES NOT APPEAR TO BE AN INVERSION NEARBY IN THE
FIRST 700 MB.
REISSUED WSW, AND LOWERED MINS IN THE SHELTERED VALLEYS OF THE
CENTRAL SO TIER AND WESTERN CATSKILLS.
630 PM UPDATE...
VERY LIGHT SNOW SHOWERS FALLING ACROSS OUR INTERIOR COUNTIES,
WHILE WE WAIT FOR WINDS TO ALIGN AND DAYTIME THERMALS TO WEAKEN.
LES WILL INCREASE BETWEEN 8 AND 10 PM, FOCUSING THE ACTIVITY OVER
THE ADVISORY AREA.
LOWERED NEAR TERM TEMPS A BIT AS WE WERE RUNNING BELOW PLAN. GRIDS
LOOK TO BE IN GOOD SHAPE SO ONLY MINOR CHANGES.
PREV DISC...
JUST WIDESPREAD LIGHT SNOW SHOWERS AND FLURRIES ARE FALLING
ACROSS CENTRAL NY AND NORTHERN PA AS OF LATE THIS AFTERNOON.
HOWEVER EXPECT ONCE THE SUN STARTS TO GO DOWN THAT SOME HEAVIER
BANDS WILL ONCE AGAIN BE ABLE TO ORGANIZE EARLY THIS EVENING.
MODEL FORECAST SOUNDINGS CONTINUE TO INDICATE PLENTY OF MOISTURE
BELOW 700 MB AND LITTLE IF ANY CAPPING INVERSION. FLOW WILL BE
FROM 290-295 DEGREES INTO THIS EVENING WITH A SLIGHT SHIFT TOWARD
295-300 DEGREES TONIGHT. 850 MB TEMPERATURES WILL CONTINUE BETWEEN
-10 AND -12 DEGREES C WITH A 100-150 MB DEEP LAYER OF MOISTURE
WITHIN THE DENDRITIC GROWTH ZONE ACROSS CENTRAL NY. BASED ON ALL
OF THIS HAVE RE-ISSUED A LAKE EFFECT SNOW ADVISORY FOR
ONEIDA/ONONDAGA AND MADISON COUNTIES FOR TONIGHT THROUGH SATURDAY
MORNING. FARTHER SOUTH LIGHTER SNOW SHOWERS COULD BRING 1 TO 3
INCHES AS FAR SOUTH AS TOMPKINS... CHENANGO... CORTLAND AND
NORTHERN BROOME COUNTIES WITH UP TO AN INCH OR SO IN THE
CATSKILLS. OTHERWISE JUST FLURRIES ARE EXPECTED. CLOUDS WILL KEEP
TEMPERATURES FROM FALLING TOO FAR TONIGHT... BUT STILL EXPECTED TO
BE WELL BELOW NORMAL WITH LATE NIGHT READINGS MAINLY IN THE LOWER
20S.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
SNOW SHOWERS WILL CONTINUE ACROSS CENTRAL NY SATURDAY MORNING...
BECOMING MORE SCATTERED BY AFTERNOON WITH INCREASED AFTERNOON
HEATING. EXPECT SOME LIGHT MULTIBANDS TO PERSIST SATURDAY NIGHT...
ALTHOUGH A CAPPING INVERSION IS FORECAST TO DEVELOP AROUND 800 MB
WITH DRYING ABOVE THE INVERSION. THIS SHOULD KEEP AMOUNTS LOWER
TOMORROW NIGHT THAN TONIGHT... ALTHOUGH AN INCH OR TWO WILL STILL
BE POSSIBLE ACROSS THE NORTHERN PART OF THE FORECAST AREA.
LINGERING FLURRIES WILL FINALLY END EARLY SUNDAY AS A HIGH
PRESSURE RIDGE BUILDS ACROSS THE AREA.
NEXT CONCERN WILL BE POTENTIAL STORM SYSTEM ON MONDAY. THE MAIN
ISSUE FOR OUR AREA WILL BE HOW FAR NORTH THE PRECIPITATION SHIELD
CAN REACH. AT THIS POINT EXPECT ANY CHANCE FOR MIXED PRECIPITATION
WILL BE LOW AS PERSISTENT BLOCKING OVER THE NORTH ATLANTIC WILL
TEND TO PUSH THE MAIN PORTION OF THIS SYSTEM TO OUR SOUTH. AT THIS
POINT ALL OF THE MODELS INDICATE A REASONABLY GOOD CHANCE FOR SOME
SNOW IN NORTHEAST PA WITH MUCH LOWER CHANCES FARTHER NORTH. THE
ECMWF HAS PROBABLY BEEN THE MOST CONSISTENT MODEL INDICATING THAT
THE NORTHERN EDGE OF THE PRECIPITATION WILL REACH THE NY/PA
BORDER. THE NAM/GFS ARE A BIT FARTHER NORTH.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
4 PM FRI UPDATE... MORE OF THE SAME EXPECTED THIS PD...AS HIGH LATITUDE
BLOCKING REMAINS ACRS GREENLAND...THE N ATLANTIC...AND INTO PTNS
OF NRN CANADA. AS A RESULT...UPR-LVL ENERGY WILL HAVE A TENDENCY
TO UNDERCUT THE BLOCK...WITH SLOW MOVING CLOSED SYSTEMS LIKELY
OVER PTNS OF SRN CANADA...AND THE NRN TIER OF THE CONUS. ONE SUCH
VORTEX IS PROGGED TO STAY ANCHORED FROM ONT/QUE...ACRS THE
MARITIME PROVINCES...AND INTO THE WRN ATLANTIC. THIS WILL ENSURE A
CONTINUATION OF BELOW TO WELL BELOW NORMAL HGTS/TEMPS NEXT WEEK
ACRS NY/PA.
AS FOR THE DAILY SENSIBLE WX...COLD...MOIST...AND CYCLONIC NW FLOW
SHOULD RULE...WITH SCTD SNOW SHWRS/FLRYS EACH DAY. GIVEN THE ZONAL
NATURE OF THE FLOW ACRS MOST OF THE CONUS...AND MID TO UPR-LVL
CONFLUENCE UNDERNEATH THE ABV MENTIONED SERN CANADIAN VORTEX...ANY
MAJOR STORMS SHOULD STAY WELL REMOVED TO OUR W AND S.
PREV DISC... 430 AM UPDATE... LITTLE CHANGE FROM EARLIER FCST
THINKING WITH MAIN ATTENTION REMAINING FOCUSED ON LATE WEEKEND AND
EARLY WORK WEEK STORM SYSTEM. HEADING INTO THE WEEKEND...A DEEP
OPEN WAVE TROUGH WILL SLOWLY DESCEND THROUGH THE CENTRAL AND
NORTHERN ROCKIES BEFORE JOINING FORCES WITH SOUTHERN STREAM
PACIFIC ENERGY LIFTING NORTHEAST THROUGH THE MEXICAN PLATEAU AND
SOUTHERN TEXAS. UPON CONSOLIDATION...SFC CYCLOGENESIS WILL OCCUR
ACROSS THE WESTERN GULF OF MEXICO. FOLLOWING THIS...BOTH SOUTHERN
AND NORTHERN STREAM SPEED MAXES WILL CONTINUE MOVING NORTHEAST
WHILE REMAINING ISOLATED FROM ONE ANOTHER WHICH WILL ALLOW FOR A
SECOND AREA OF LOW PRESSURE TO DEVELOP ACROSS THE SOUTHEAST AS
EARLY AS SUN NEAR THE FLORIDA PANHANDLE. BOTH LOWS WILL THEN
CONTINUE LIFTING NORTHEAST WITH THE FIRST LOW EVENTUALLY REACHING
THE CENTRAL APPALACHIANS WHERE IT WILL THEN TRANSFER ENERGY TO THE
NEW SOUTHERN STREAM SYSTEM WORKING UP TH EAST COAST. AS THIS
OCCURS...SNOW WILL LIFT NORTH INTO OUR AREA AS EARLY AS 06Z MONDAY
WITH THE NORTHERN EXTENT OF THE DEFORMATION BAND SNOWFALL
POTENTIALLY ONLY REACHING THE CENTRAL FINGER LAKES AS MAIN LOW
REMAINS SOUTH OF THE FCST AREA. DURING THE DAY ON MONDAY...GFS
FCST SOUNDINGS SHOW SOME DRY AIR WORKING INTO THE ICE CRYSTAL
GENERATION ZONE WHICH COMBINED WITH DAYTIME HEATING...WILL LIKELY
RESULT IN A SWITCHOVER FROM SN TO RA OR DZ. FOR NOW...HAVE NOT
ATTEMPTED TO GET TO DETERMINISTIC IN THE GRIDS AS MODEL TRENDS
CONTINUE TO EVOLVE WITH THIS FEATURE. THAT BEING SAID...EXTENDED
RANGE MODELS DO INDICATE UNSETTLED WX WILL REMAIN OVER THE REGION
AS CYCLONIC FLOW PREVAILS ALOFT. THIS SHOULD ENSURE BELOW NORMAL
TEMPS AND CONTINUED CHANCES FOR PRECIP THROUGH LATE WEEK.
130 PM UPDATE... 12Z GUIDANCE CONTS TO BE ON TRACK FOR
POTENTIAL STORM FOR EARLY NEXT WEEK. 12Z NAM/GFS IN LINE WITH 06Z
GFS REGARDING MVMT OF SYSTEM SOUTH OF THE MASON-DIXON LINE. THESE
MODELS ARE IN AGREEMENT WITH 00Z EURO THO MODELS DIFFER ON TIMING
OF QPF MVG INTO THE REGION. BASED ON MVMNT OF SYSTEM EXPECT PCPN
TO MV IN SUN NIGHT AND HV TRENDED TWD LATEST HPC GUIDANCE WITH CHC
POPS FOR THE SOUTHERN TIER AND POINTS SOUTH. MODEL TRENDS INDICATE
HIPRES WL PUMP COLD NRLY AIR DOWN FM CANADA ENUF TO KEEP PTYPE AS
ALL SNOW FOR SUN NGT INTO MON MRNG. THEN AS VLYS WARM THRU THE
AFTN, RAIN WILL START TO MIX IN DRG THE AFTN HRS. ALL GEFS MEMBERS
AGREE WITH OPERATIONAL GFS ON TRACK OF SYSTEM.
TEMPS EXPECTED TO RMN WELL BLO NORMAL THRU THE END OF THE PD WITH
HIGHS ARND 40 AND LOWS IN THE LWR-MID 20S.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
SHRT WV PASSING THRU THE AREA IS ENHANCING THE LAKE EFFECT SNOWS
OVER CNTRL NY. ALSO...LOSS OF HTG IS ALLOWING THE BANDS TO BECOME
BETTER ORGANIZED. XPCT MVFR AND OCNL IFR CONDS FOR MUCH OF THE NGT
AT THE NY STATIONS XCPT ELM WIND WILL BECOME LESS GUSTY OVRNGT AS
WELL. CONDS WILL IMPRV ONCE AGAIN ON SAT AFT DAYBRK AS SOMEWHAT
DRIER AIR MVES IN.
.OUTLOOK...
SUN...MAINLY VFR.
SUN NGT TO MON...MVFR/IFR IN SNOW...SPCLY AT KAVP/KELM/KBGM.
TUE/WED...PSBL RESTRICTIONS IN SHSN/FLRYS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...LAKE EFFECT SNOW ADVISORY UNTIL NOON EDT TODAY FOR NYZ009-018-
036-037.
&&
$$
SYNOPSIS...MSE
NEAR TERM...CMG/DJP/MSE
SHORT TERM...MSE
LONG TERM...CMG/MLJ
AVIATION...DGM/MLJ
AREA FORECAST DISCUSSION
NWS RALEIGH NC
825 PM EDT SUN MAR 24 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM OVER THE MISSISSIPPI RIVER VALLEY WILL MOVE
NORTHEAST INTO THE OHIO VALLEY TONIGHT. A SECOND AREA OF LOW
PRESSURE WILL MOVE SLOWLY UP THE NC COAST TO NEAR NEW JERSEY BY
MONDAY AFTERNOON. A COOL NORTHWEST FLOW WILL CONTINUE ACROSS THE
REGION THROUGH WEDNESDAY.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
AS OF 300 PM SUNDAY...
THROUGH TONIGHT:
THE SURFACE LOW THAT DEVELOPED OVER THE SOUTHERN MISSISSIPPI RIVER
VALLEY OVERNIGHT HAS SPLIT INTO TWO SEPARATE LOWS...WITH ONE
DEEPENING AS IT MOVES NORTHEAST ALONG THE WEST SIDE OF THE
APPALACHIANS...AND THE SECOND MOVING OFF THE SE ATLANTIC COAST. AS
THE LOW CONTINUES TO MOVE OFF AND ALONG THE ATLANTIC COAST...UPPER
LEVEL WINDS SHOULD BRIEFLY BACK AROUND TO MORE SOUTHEASTERLY BEFORE
THE PARENT LOW OVER THE OHIO RIVER VALLEY MOVES EAST THROUGH THE MID
ATLANTIC. THE HRRR AND THE HIRES WRF-ARW CONVECTION ALLOWING
MODELS...WHICH ARE CAPTURING THE CURRENT REFLECTIVITIES BEST...
INDICATE AN AREA OF SHOWERS DEVELOPING AHEAD OF THE COLD FRONT
TONIGHT. AS SUCH...CONTINUE GRADUALLY DECREASING PRECIP CHANCES
ACROSS THE SOUTH AND EAST THIS AFTERNOON AND FROM WEST TO EAST
ACROSS THE AREA BEHIND THE FRONT OVERNIGHT. HPC GUIDANCE RAINFALL
AMOUNTS APPEAR TO BE A BIT OVERDONE. THUS HAVE GONE MORE TOWARD THE
TREND OF THE HRRR...GIVEN THE DRY SLOT MOVING INTO THE WEST AND THE
FORECAST REFLECTIVITIES FROM THE CONVECTION ALLOWING MODELS. WITH
THE HYBRID COLD AIR DAMMING EVENT LINGERING INTO TONIGHT...WILL SEE
NEAR STEADY TEMPS SLOWLY FALL AFTER SUNSET INTO THE LOW 30S NORTH TO
MID 30S SOUTH AND EAST BY DAYBREAK. THERE IS STILL SOME CONCERN THAT
THE BOUNDARY LAYER MAY COOL ENOUGH TO REACH FREEZING MONDAY MORNING
IN THE TRIAD AREA WHICH COULD RESULT IN SOME BLACK ICE. CONFIDENCE
IN THIS OCCURRING IS STILL LOW AT THIS TIME GIVEN THAT BOUNDARY
LAYER WINDS SHOULD STAY UP AROUND 5 KTS OR SO OVERNIGHT...WHICH WILL
LIMIT SURFACE COOLING AND MAY DRY THINGS OUT ENOUGH TO MITIGATE ANY
BLACK ICE FORMATION. ALSO...IT APPEARS THAT SKIES SHOULD REMAIN
CLOUDY THROUGH DAYBREAK...LIMITING RADIATIONAL COOLING.
MONDAY AND MONDAY NIGHT:
EXPECT THE LOW ALONG THE ATLANTIC COAST TO MERGE WITH THE INLAND LOW
MOVING EAST ACROSS THE MID ATLANTIC ON MONDAY...WITH LINGERING
CHANCES FOR SOME LIGHT RAINFALL/SPRINKLES ACROSS THE NORTH...MAINLY
IN THE AFTERNOON. WITH WINDS BACKING BEHIND THE FRONT AND COLDER AIR
ADVECTING INTO CENTRAL NC...EXPECT HIGH TEMPS IN THE MID TO UPPER
40S NORTH TO MID 50S ACROSS THE SOUTH. WINDS WILL BE STRONG AND
GUSTY OUT OF THE WNW ON MONDAY AND INTO MONDAY NIGHT...EXPECTING
SUSTAINED AT 15-20 KTS...GUSTING TO AROUND 30 KTS. MONDAY NIGHT LOWS
IN THE LOW TO MID 30S...WITH SOME OF THE OUTLYING AREAS POTENTIALLY
DIPPING INTO THE UPPER 20S.
&&
.SHORT TERM /TUESDAY AND TUESDAY NIGHT/...
AS OF 315 PM SUNDAY...
THE PATTERN ALOFT WILL CHANGE LITTLE - ANOTHER MID-UPPER
LOW...ANOTHER DAY. THIS ONE...CENTERED OVER THE NORTHERN PLAINS THIS
AFTERNOON...WILL SHEAR EASTWARD ACROSS THE SOUTHERN APPALACHIANS AND
NC DURING THE DAY TUE - ON A FAVORABLE TRACK FOR A LITTLE LIGHT
PRECIPITATION FOR CENTRAL NC. DESPITE THE FAVORABLE TRACK AND
ASSOCIATED DYNAMICS...PROJECTED THERMODYNAMICS...AS CHARACTERIZED BY
MID LEVEL (H85-5) LAPSE RATES OF ONLY AROUND 5.5 C/KM...HAVE TRENDED
MUCH WEAKER. NONETHELESS...RELATIVELY DEEP MIXED PHASE SATURATION
BETWEEN 5 AND 15 THOUSAND FT AMIDST POCKETS OF WEAK INSTABILITY ON
THE ORDER OF AROUND 100 OR SO J/KG...SHOULD SUPPORT THE DEVELOPMENT
OF DIURNALLY-ENHANCED SCATTERED SHOWERS...OR SPRINKLES OWING TO A
DRY ADIABATIC...4 THOUSAND FT SUB-CLOUD LAYER. WILL ACCORDINGLY
RETAIN THE SLIGHT TO LOW CHANCE PROBABILITY OF A FEW HUNDREDTHS OF
AN INCH LIQUID...WITH THE LOWEST CHANCES ACROSS THE SOUTHERN
PIEDMONT WHERE THE DEPTH OF THE MOISTURE IS FORECAST TO BE
SHALLOWER/WARMER. IF PRECIPITATION WERE TO OCCUR BEFORE 10-11
AM...WHICH IS UNLIKELY GIVEN THE ABSENCE OF DIURNALLY-DRIVEN WEAK
INSTABILITY BEFORE THAT TIME...THERE WOULD BE THE POTENTIAL FOR A
LITTLE SNOW MIXED WITH THE RAIN OVER THE WESTERN PIEDMONT.
REGARDLESS...NO IMPACT WOULD OCCUR GIVEN THE MARCH SUN ANGLE...AND
TEMPERATURES "WARMING" INTO THE MIDDLE 40S NORTH TO LOWER 50S
SOUTH...BENEATH A CLOUDY OR MOSTLY SO SKY. CLEARING AND COLD TUE
NIGHT...WITH LOWS IN THE UPPER 20S TO LOWER 30S.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 255 PM SUNDAY...
NORTHWEST FLOW AND SLOWLY RISING HEIGHTS ALOFT...AS THE EASTERN
CONUS TROUGH GRADUALLY RELAXES...WILL RULE THROUGH THE MEDIUM RANGE.
BOTH CLIMATOLOGY AND NWP GUIDANCE SUGGEST THIS PERIOD WILL
CONSEQUENTLY BE DRY...AND COOLER THAN AVERAGE...THOUGH TRENDING BACK
INTO THE 60S SUN. THE CHILLIEST TEMPERATURES WILL BE THU AND FRI
NIGHTS AS THE SURFACE RIDGE DRIFTS OVERHEAD...WITH COOLEST READINGS
IN THE MID-UPPER 20S OVER THE WESTERN PIEDMONT FRI MORNING. IT STILL
APPEARS THE GULF OF MEXICO WILL BE BRIEFLY OPEN AHEAD OF A S/W
TROUGH AMPLIFYING THROUGH THE GREAT LAKES THIS WEEKEND...BUT
TIMING...AND DEGREE OF MOISTURE EAST OF THE MOUNTAINS AMIDST DEEP
LAYER WNW FLOW...REMAINS UNCERTAIN. AS SUCH...THE FORECAST WILL
BE KEPT DRY DURING THE WEEKEND.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 825 PM SUNDAY...
HIGH CONFIDENCE EXISTS FOR LOW END MVFR TO IFR CIGS AND VSBYS TO
CONTINUE INTO THE OVERNIGHT HOURS AS A TANDEM OF LOW PRESSURE
SYSTEMS AFFECT THE REGION. A LOW TRACKING UP THE NC-VA COAST WILL
MAINTAIN COOL MOIST N-NE FLOW UNTIL MIDNIGHT...AFTER WHICH THE FLOW
WILL WEAKEN. THIS LACK OF MIXING WILL LIKELY ALLOW CEILINGS TO LOWER
INTO THE LOW END IFR WITH POCKETS OF DRIZZLE POSSIBLE...MAINLY IN
THE NW PIEDMONT. IF PRECIP INTENSITY BECOMES HEAVY ENOUGH...MAY SEE
SPORADIC BURST OF WET SNOW THOUGH CONFIDENCE NOT HIGH ENOUGH TO
MENTION IN THE TAF FORECAST AT THIS TIME.
A SURFACE BOUNDARY WILL SWEEP ACROSS THE REGION EARLY MONDAY
MORNING. BEHIND THIS BOUNDARY...WESTERLY WIND WILL INCREASE TO
AROUND 15 MPH WITH FREQUENT GUSTS 25 TO 30 MPH. IF THE GFS
VERIFIES...MAY SEE A FEW GUSTS IN THE SOUTH (KFAY VICINITY) NEAR 35
MPH. THESE WINDS WILL ADVECT DRIER AIR INTO THE REGION...LIFTING
CEILINGS AND EVENTUALLY DISSIPATING THE CLOUD COVERAGE. EXPECT VFR
CONDITIONS TO OVERSPREAD CENTRAL NC FROM THE SW BETWEEN 10Z-14Z.
A SERIES OF UPPER LEVEL DISTURBANCES WILL TRACK ACROSS OUR REGION
LATE MONDAY THROUGH WEDNESDAY. THIS WILL CAUSE 3-6 HOUR PERIODS OF
POSSIBLE MVFR CEILINGS ALONG WITH FEW-SCATTERED RAIN AND/OR SNOW
SHOWERS. OTHER WISE VFR CONDITIONS WILL DOMINATE.
FOR THURSDAY INTO FRIDAY...EXPECT A HIGH LIKELIHOOD OF VFR
CONDITIONS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...WSS/BLAES
NEAR TERM...KC
SHORT TERM...MWS
LONG TERM...MWS
AVIATION...WSS
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
801 PM EDT SUN MAR 24 2013
.SYNOPSIS...
LOW PRESSURE OVER KENTUCKY WILL MOVE ACROSS SOUTHERN OHIO
OVERNIGHT. THE LOW WILL WEAKEN ON MONDAY AS A NEW LOW DEEPENS
RAPIDLY OFF THE MID ATLANTIC COAST. THIS DEEP LOW WILL EXTEND A
TROUGH WEST ACROSS THE GREAT LAKES REGION INTO WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
UPDATE ALREADY OUT. GIVEN DRY NE FLOW...CURRENT OBS AND LATEST
RADAR HAVE SLOWED DOWN THE ONSET OF THE SNOW A COUPLE OF HOURS
MOST AREAS. CURRENT RADAR RETURNS OVER THE LOCAL AREA ARE JUST
CLOUDS AND VIRGA. THE SNOW SHOULD REACH THE SOUTHERN END OF THE
AREA AFTER 00Z AND KMFD AROUND 03Z. IT WILL BE AFTER MIDNIGHT
BEFORE ANYTHING MORE THAN FLURRIES FALLS IN THE CLEVELAND AREA.
ORIGINAL...GUIDANCE CONVERGING ON A SOLUTION BRINGING THE SURFACE LOW FROM
WESTERN KENTUCKY INTO SOUTHERN OHIO OVERNIGHT. WEAK WAVE
INCREASING RETURN ON THE RADAR ACROSS CENTRAL AND SOUTHERN OHIO
THROUGH THE AFTERNOON. MUCH OF THIS ACROSS THE NORTHWEST AND NORTH
CENTRAL COUNTIES HAS BEEN VIRGA ALTHOUGH THERE ARE POCKETS OF
LIGHT SNOW AS WELL. FOLLOWING THE HRRR THIS PRECIP WILL CONTINUE
TO SPREAD INTO THE AREA BUT THEN WEAKEN AND DISSIPATE EARLY
EVENING. WILL HAVE CHANCE POPS IN PLACE TO COVER THE SNOW WITH
THIS ADVANCE WAVE. OTHERWISE MAIN PRECIP ASSOCIATED WITH THE STORM
SYSTEM NOW MOVING INTO/THRU SRN INDIANA AND ILLINOIS.
AGAIN...FOLLOWING HRRR EXPECT THIS TO MOVE INTO OUR AREA FROM THE
SSW BETWEEN 00-03Z. SNOW WILL CONTINUE TO MOVE INTO THE AREA FROM
THE SOUTH WITH MODERATE SNOW LIKELY COVERING THE SOUTHERN TIER OF
COUNTIES FROM 05Z-10Z. EXPECTING 4-6 INCHES ACROSS THE SOUTHERN
TIER WITH 3-5 FURTHER NORTH IN THE ADVISORY.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY NIGHT/...
ADVISORY/WARNING WILL BE ON GOING AT 12Z WITH SNOW LIKELY OCCURRING
ACROSS MUCH OF THE AREA. EXPECTING ANOTHER COUPLE INCHES ACROSS
THE SOUTH/SOUTHEAST COUNTIES THAT WILL BRING STORM TOTALS IN THE
WARNING AREA TO 5 TO 7...POSSIBLY A FEW 8`S WITH 3 TO 5...POSSIBLY
6 IN THE ADVISORY AREA BY NOON. THROUGH THE AFTERNOON MOISTURE AND
LIFT WILL BE WEAKENING AS THE ENERGY OF THE SYSTEM TRANSLATES TO
THE EAST COAST AND THE OHIO SURFACE LOW FILLS. MONDAY NIGHT
THROUGH TUESDAY NIGHT WILL CONTINUE WITH LOW CHANCE POPS IN A
GENERALLY MOIST NORTHERLY CYCLONIC FLOW...STILL INFLUENCED BY THE
EXITING SURFACE LOW WELL OFF THE EAST COAST. MID WEEK HIGH
PRESSURE WILL TRY TO BUILD IN AS THE LOW GETS HALF WAY TO EUROPE.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
A FEW LINGERING SNOW SHOWERS IN THE SNOWBELT ON THURSDAY WITH 850 MB
TEMPS ONLY MINUS 8C. MODELS IN REASONABLE AGREEMENT MOVING HIGH
PRESSURE OVER THE AREA DURING THE DAY ON FRIDAY. HIGH PRESSURE WILL
REMAIN OVER THE AREA WELL INTO THE WEEKEND. MODELS MOVE NEXT
SYSTEM THROUGH ON SUNDAY...LEANED TOWARD THE SLOWER GFS SLOWER.
SHOULD WARM INTO THE 40S ALLOWING FOR RAIN.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
LOW PRESSURE WILL TRACK ACROSS SOUTHERN OHIO OVERNIGHT BRINGING
WIDESPREAD SNOW TO MOST OF NORTHERN OHIO. THE HEAVIEST SNOW OF 4-6
INCHES IS EXPECTED AT FDY/MFD/CAK/YNG WITH LESSER AMOUNTS FURTHER
NORTH TOWARDS CLE WITH TOL/ERI ON THE FRINGES. SNOW IS APPROACHING
FROM THE SW AND WILL MOVE INTO FDY/MFD AROUND 04Z...REACHING CLE/YNG
AROUND 06Z. CEILINGS WILL REMAIN VFR AT MOST LOCATIONS FOR A COUPLE
MORE HOURS BUT DROP QUICKLY TO MVFR AND IFR AS SNOW BEGINS. HEAVY
BURSTS OF SNOW WILL FALL BETWEEN 06-12Z WITH LOCALLY LIFR...WITH
LIGHTER SNOW CONTINUING THROUGH THE DAY ON MONDAY AND EVENTUALLY
TAPERING OFF TOWARDS THE END OF THE TAF PERIOD. NORTHEASTERLY
WINDS WILL BE BREEZY OVERNIGHT...ESPECIALLY NW OF THE LOW TRACK AT
TOL/FDY. GUSTS OF 25-30 KNOTS WILL CONTINUE THERE WITH OTHER SITES
GUSTING TO 20-25 KNOTS. SOME DECREASE IN WINDS ARE EXPECTED ACROSS
CENTRAL AND EASTERN OHIO TOWARDS DAWN AS THE LOW PASSES BEFORE
INCREASING AGAIN DURING THE DAYTIME HOURS.
.OUTLOOK...NON VFR IN SHSN CONTINUING INTO WEDNESDAY.
&&
.MARINE...
LOW PRESSURE OVER KENTUCKY WILL MOVE ACROSS SOUTHERN OHIO TONIGHT.
AS IT DOES WINDS WIND INCREASE TO 20 TO 25 KNOTS ACROSS ENTIRE LAKE.
WINDS TURN TO THE NORTHWEST AS THE LOW MOVES OFF THE MID ATLANTIC
COAST MONDAY AFTERNOON. CONDITIONS DROP BELOW SMALL CRAFT ADVISORY
CRITERIA TUESDAY AS GRADIENT WEAKENS. HIGH PRESSURE FINALLY BUILDS
OVER THE LAKE ON FRIDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...WINTER STORM WARNING UNTIL NOON EDT MONDAY FOR OHZ036>038-047.
WINTER WEATHER ADVISORY UNTIL NOON EDT MONDAY FOR OHZ017>022-
027>033.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT TUESDAY FOR LEZ142>149.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK/KUBINA
SHORT TERM...TK
LONG TERM...DJB
AVIATION...KEC
MARINE...DJB
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
545 PM CDT SAT MAR 23 2013
.UPDATE...
ISSUED AT 538 PM CDT SAT MAR 23 2013
MADE A FEW MINOR MODIFICATIONS TO THE GRIDS BUT DID NOT CHANGE A
WHILE LOT. SLOWED DOWN THE EXPANSION OF MEASURABLE SNOWFALL
POTENTIAL A COUPLE OF HOURS TONIGHT AND IF THE CURRENT TRENDS
CONTINUE MAY NEED TO BACK OFF A LITTLE MORE THROUGH THE OVERNIGHT
HOURS. ONE FEATURE NOTICEABLE ON THE RADAR IS THE MID LEVEL DRY
PUNCH MOVING TOWARDS INTERSTATE 29 WITH A SIGNIFICANT DECREASE
REFLECTIVITY OVER THE LAST HOUR. THIS DRY LAYER REALLY STARTS TO
SHUT DOWN SATURATION IN THE DENDRITIC LAYER AND SUGGESTS THAT
PRETTY MUCH ONLY LOCATIONS FROM ABOUT VERMILLION TO JACKSON SOUTH
WILL SEE ANY MEASURABLE SNOWFALL TONIGHT. NO INSTABILITY...NO
TROUGH OF WARM AIR ALOFT AND NO MID LEVEL FRONTAL FORCING PRETTY
MUCH JUST LEAVES UPPER LEVEL SUPPORT AND A MARGINALLY DEEP
DENDRITIC LAYER TO WORK WITH FOR SNOW PRODUCTION. THE LATEST
TRENDS FROM THE RAP AND NAM12 HINT AT THIS DRY LAYER SUPPRESSING
SNOW PRODUCTION WITH LITTLE OR NO ACCUMULATION WEST OF A YANKTON
TO IVANHOE MINNESOTA LINE. IF THESE TRENDS CAN BE TRUSTED MAY NEED
TO DECREASE SNOW AMOUNTS FURTHER ALONG AND WEST OF THIS LINE.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 341 PM CDT SAT MAR 23 2013
LIGHT SNOW SPREADING NORTHEAST OUT OF NEBRASKA THIS AFTERNOON. PLENTY
OF MOISTURE IN DENDRITIC LAYER WITH WEAK LIFT EXPECTED ACROSS THE
EASTERN CWA OVERNIGHT. MAIN FORCING WILL REMAIN WELL SOUTH OF
CWA...BUT WITH THE WEAK UNFOCUSED LIFT OVER CWA TONIGHT...EXPECT
LIGHT SNOW TO PERSIST MOST OF NIGHT AS IT SPREADS NORTHEAST. THE MAIN
AREA OF LIGHT SNOW WILL LIKELY BE EAST OF A YKN-BKX LINE WITH BEST
CHANCE FOR 1 TO 2 INCHES OF SNOW ACROSS NORTHWEST IOWA...WITH LESSER
AMOUNTS TO THE NORTH AND WEST. LIGHT SNOW WILL LINGER EAST OF I29
SUNDAY MORNING...AND THEN ROTATE BACK SOUTHWEST DURING THE AFTERNOON
AS WEAK INVERTED TROUGH ROTATES SOUTHWEST AS SECONDARY WEAK WAVE
DROPS SOUTH OUT OF NORTH DAKOTA. SO WILL KEEP POPS IN FORECAST WITH
LIKELY POPS ACROSS THE EAST. AMOUNTS WILL AGAIN BE LIGHT WITH MOST
AREAS LESS THAN 1 INCH OF SNOW ON SUNDAY. TEMPERATURES WILL REMAIN
WELL BELOW NORMAL ON SUNDAY WITH HIGHS SIMILAR TO TODAY. CLOUD COVER
SHOULD HELP HOLD TEMPERATURES UP TONIGHT.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 341 PM CDT SAT MAR 23 2013
AS THE UPPER LOW CONTINUES TO PUSH SOUTH ALONG WITH A WEAK
INVERTED TROUGH...LIGHT SNOW AND FLURRIES WILL CONTINUE THROUGH
SUNDAY NIGHT. LOW LEVEL LAPSE RATES REMAIN PRETTY STEEP...THUS COULD
SEE SOME BRIEFLY HEAVIER SNOW SHOWERS MIXED IN WITH THE LIGHTER
SNOW. OVERALL THOUGH NOT EXPECTING MUCH MORE THAN ABOUT AN INCH OF
ADDITIONAL ACCUMULATION. CLOUD COVER AND A BLUSTERY NORTHERLY WIND
WILL KEEP LOWS FROM FALLING TOO MUCH...GENERALLY THINKING LOWER 20S.
LIFT BECOMES EVEN WEAKER ON MONDAY...BUT ATMOSPHERE REMAINS NEARLY
SATURATED...THUS THINKING FLURRIES LINGER THROUGH THE DAY WITH ONLY
A DUSTING OR LESS EXPECTED. HIGHS WILL REMAIN WELL BELOW
NORMAL...UPPER 20S TO LOWER 30S. CLOUDS SLOWLY BEGIN TO DISSIPATE
MONDAY NIGHT FROM WEST TO EAST. LOWS A BIT TRICKY AND DEPENDENT ON
HOW FAST CLOUDS CLEAR AND WINDS DIE OFF...THUS WENT CLOSE TO
CONSENSUS FOR NOW UNTIL CLOUD COVER AND WINDS BECOME MORE
CERTAIN...GENERALLY IN THE TEENS.
WEAK RIDGING TRIES TO BUILD TUESDAY INTO THE END OF THE WORK WEEK.
THIS WILL RESULT IN WARMING...BUT STILL BELOW NORMAL...TEMPERATURES
EACH DAY...WITH HIGHS IN THE 40S TO AROUND 50 BY WEEKS END. OVERALL
PRECIP CHANCES LOOK PRETTY LOW THROUGH THE EXTENDED. WEAK WAVE ON
FRIDAY COULD BRING A LITTLE BIT OF LIGHT RAIN...BUT MODEL
DIFFERENCES AND INCONSISTENCY TOO BIG TO INCLUDE ANY POPS AT THIS
TIME. ANOTHER POTENTIAL WEAK NORTHERN STREAM WAVE MAY COME THROUGH
SATURDAY OR SATURDAY NIGHT WITH SOME LIGHT RAIN OR SNOW. SO OVERALL
MAYBE A FEW LIGHT PRECIPITATION CHANCES MID TO LATE NEXT WEEK...BUT
TIMING STILL UNCERTAIN. MODELS COMING INTO BETTER AGREEMENT THAT A
CLOSED UPPER LOW WILL COME INTO THE CALIFORNIA COAST ON SATURDAY
EVENTUALLY MOVING INTO THE PLAINS BY EARLY THE FOLLOWING WEEK. THIS
WOULD BE OUR NEXT CHANCE OF MORE SIGNIFICANT PRECIPITATION AMOUNTS.
THE UPPER AIR PATTERN MAY ONCE AGAIN FORCE THIS SYSTEM SOUTH...BUT
WE WILL HAVE TO MONITOR TRENDS OVER THE COMING WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1210 PM CDT SAT MAR 23 2013
MVFR CEILINGS ALONG AND WEST OF THE JAMES RIVER WILL PERSIST
THROUGH 18Z SUNDAY. VFR CEILINGS EAST OF THE JAMES RIVER WILL
GRADUALLY BECOME MVFR DURING THE OVERNIGHT HOURS AND PERSIST
THROUGH 18Z SUNDAY. LIGHT SNOW OVER NEBRASKA WILL SPREAD SLOWLY
NORTHEAST THROUGH TONIGHT AND PERSIST INTO SUNDAY MORNING...WITH
THE LIGHT SNOW EXPECTED TO BE MAINLY EAST OF THE JAMES RIVER.
VISIBILITIES COULD DROP TO ONE MILE OR LESS MAINLY OVER NORTHWEST
IOWA.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...08
SHORT TERM...
LONG TERM...CHENARD
AVIATION...
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
230 PM CDT SAT MAR 23 2013
.UPDATE...
MAIN REASON FOR UPDATE WAS THE DRASTICALLY LOWER HIGH TEMPS ACROSS
THE AREA. AN AREA OF LOW CLOUDS CONTINUES TO BLANKET THE OK PANHANDLE
AND THE NORTHERN AND EASTERN TX PANHANDLE THIS AFTERNOON. THE
COMBINATION OF THIS DENSE CLOUD COVER AND UPSLOPE LOW-LEVEL FLOW HAS
PREVENTED TEMPS FROM CLIMBING MUCH ABOVE THE MID 30S. ELSEWHERE LESS
CLOUD COVER HAS ALLOWED FOR TEMPS TO CLIMB INTO THE UPPER 50S
ALTHOUGH STILL HAD TO TRIM INHERITED HIGH TEMPS DOWN A FEW DEGREES.
BESIDES TEMPS...HAVE INCREASED DEW POINTS AS LIGHT UPSLOPE FLOW
ACROSS THE REGION HAS KEPT MOISTURE IN PLACE LONGER THAN WHAT WAS
PREVIOUSLY FORECAST. A COLD FRONT WILL CONTINUE TO PUSH SOUTH LATE
THIS AFTERNOON AND STRONG PRESSURE RISES AND A TIGHTENING PRESSURE
GRADIENT WILL RESULT IN SFC WINDS TO QUICKLY INCREASE. OTHERWISE
GOING FORECAST IS IN FINE SHAPE AND ONLY MADE MINOR ADJUSTMENTS TO
OTHER FORECAST PARAMETERS.
CLK
&&
.PREV DISCUSSION... /ISSUED 106 PM CDT SAT MAR 23 2013/
AVIATION...
/18Z TAFS/ LOW CONFIDENCE FORECAST ESPECIALLY OVER THE FIRST 9 HOURS
OF THE FORECAST PERIOD. CURRENT SFC ANALYSIS INDICATES A SURFACE LOW
OVER EASTERN NM WITH A COLD FRONT OVER THE OK PANHANDLE. THIS FRONT
WILL CONTINUE TO SLIDE SOUTH DURING THE AFTERNOON WHILE THE SURFACE
TROUGH SLIDES TO THE SOUTHEAST. DESPITE THE RELATIVELY LIGHT AND
VARIABLE WINDS THIS MORNING...EXPECT WINDS TO STRENGTHEN BY LATE THIS
AFTERNOON WITH SUSTAINED WINDS QUICKLY RAMPING UP TO AROUND 25-30 KTS
WITH GUSTS UP TO 40 KTS DUE TO THE COMBINATION OF A TIGHT PRESSURE
GRADIENT AND STRONG PRESSURE RISES BEHIND THE FRONT. GIVEN THESE
PARAMETERS WILL CONTINUE WITH THE AWW FOR KAMA FROM 19Z- 05Z SUN.
THESE STRONG WINDS CAN ALSO RESULT IN AREAS OF BLOWING DUST
/PRIMARILY AT KAMA/ ALTHOUGH WITH WINDS OUT OF THE
NORTHWEST...CONFIDENCE IN THIS OCCURRING IS LOW. BY THIS
EVENING EXPECT A BAND OF -SN TO GRAZE THE KGUY/KDHT TERMINALS. HIGH-
RES MODELS SUGGEST THE -SN TO START AROUND 21Z AT KGUY AND SPREAD
SOUTH TO KDHT BY 00Z. LOOKS LIKE -SN WILL STAY NORTH OF THE KAMA
TERMINAL. ANY -SN SHOULD END BY AROUND 03Z SUN. GIVEN THE ONSET OF
-SN...EXPECT MAINLY MVFR TO LIFR CONDITIONS AT KDHT/KGUY RESPECTIVELY
WHILE KAMA SHOULD REMAIN VFR /ALTHOUGH LOW CLOUDS WITH MVFR CIGS ARE
A POSSIBIILITY OVERNIGHT/. EXPECT A GRADUAL IMPROVEMENT TO VFR AT
KGUY/KDHT SUN MORNING. STRONG AND GUSTY NORTHERLY WINDS WILL
GRADUALLY DIMINISH TO 15 KTS SUSTAINED TOWARD THE END OF THE FORECAST
PERIOD.
CLK
PREV DISCUSSION... /ISSUED 714 AM CDT SAT MAR 23 2013/
AVIATION...DISCUSSION FOR 12Z TAFS
KAMA...
BRIEF CLEARING COULD FILL BACK IN WITH A BKN MVFR DECK OVER THE NEXT
HR. THIS DECK SHOULD THEN LIFT BACK BY 15Z TO VFR CONDITIONS. STRONG
AND GUSTY WEST WINDS WILL DEVELOP THIS AFTERNOON...ESPECIALLY AFTER
20Z. THESE WINDS COULD KICK UP SOME VISIBILITY REDUCING DUST AS THEY
GUST TO NEAR 45 KTS. WINDS WILL SHIFT TO THE NW AROUND 23Z AND
CONTINUE TO GUST TO NEAR OR ABOVE 40 KTS THROUGH 02Z. AFTER
02Z...WINDS SHOULD BEGIN A SLOW WEAKENING TREND. MVFR CIGS COULD SET
BACK IN FOR A BIT TONIGHT...BUT UNCERTAINTY REMAINS TOO HIGH TO
INCLUDE.
KDHT...
WINDS SHOULD GENERALLY BE OUT THE NNW THE ENTIRE PERIOD. LIGHT WINDS
SHOULD DOMINATE THROUGH 21Z. AFTER 21Z...WINDS WILL STRENGTHEN AND
GUST TO AROUND 40 KTS. THERE COULD ALSO BE A BAND OF SNOW THAT MOVES
THROUGH LATE THIS AFTERNOON. MVFR CIGS SHOULD BE NOTED FOR A PERIOD
THIS EVENING. WINDS WILL RELAX AFTER 06Z AND VFR CONDITIONS SHOULD
TAKE OVER.
KGUY...
KGUY SHOULD STAY IN THE PROVERBIAL SOUP FOR MUCH OF THE DAY TODAY AS
HIGH END IFR OR LOW END MVFR CIGS DOMINATE. WINDS WILL START OF AN
EASTERLY DIRECTION BEFORE TURNING TO THE NORTH AND INCREASING IN
SPEED AFTER 21Z. A BAND OF SNOW COULD AFFECT THE TERMINAL BETWEEN 21Z
AND 03Z...WITH DRYING CONDITIONS NOTED AFTER 03Z. MVFR CIGS COULD
VERY WELL HANG ON THROUGH SATURDAY NIGHT AT KGUY.
SIMPSON
PREV DISCUSSION... /ISSUED 602 AM CDT SAT MAR 23 2013/
DISCUSSION...
TODAY-TONIGHT: LOTS OF WEATHER COMING. THAT PRETTY MUCH SUMS UP THE
FORECAST FOR TODAY AS WE EXPECT RAIN, POSSIBLY A THUNDERSTORM, SNOW,
HIGH WIND, AND DUST TO ALL BE OBSERVED ACROSS THE PANHANDLES.
WIND: A STRONG COLD FRONT IS SCHEDULED TO ENTER THE OKLAHOMA
PANHANDLE BY EARLY THIS AFTERNOON AND PUSH SOUTH OF THE TEXAS
PANHANDLE BY LATE THIS AFTERNOON. AHEAD OF THE FRONT, VERY STRONG
WESTERLY WINDS ARE EXPECTED TO DEVELOP BETWEEN 3 AND 4 PM, ESPECIALLY
ACROSS THE WESTERN TEXAS PANHANDLE WHERE A FEW ISOLATED WIND GUSTS UP
TO 60 MPH WILL BE POSSIBLE. NOT VERY CONFIDENT THAT ALL AREAS IN THE
HIGH WIND WARNING WILL GUST TO 60 MPH. AS THE FRONT MOVES THROUGH,
WINDS WILL SHIFT TO THE NORTH AND WILL REMAIN BETWEEN 20 AND 35 MPH
OVERNIGHT AT ALL LOCATIONS. IF THE COLD FRONT ARRIVES SOONER THAN
FORECAST, THE THREAT FOR HIGH WINDS WILL BE GREATLY DIMINISHED.
DUST: DUE TO THE STRONG WESTERLY WINDS, BLOWING DUST WILL MOVE INTO
OUR AREA FROM EASTERN NEW MEXICO THIS AFTERNOON AND WILL LIKELY
IMPACT LOCATIONS SOUTH AND WEST OF A DALHART TO BORGER TO CLAUDE
LINE. VISIBILITIES COULD BE REDUCED TO LESS THAN 2 MILES, ESPECIALLY
ACROSS DEAF SMITH COUNTY.
PRECIPITATION CHANCES: DRIZZLE IS EXPECTED THIS MORNING NORTH OF A
TEXLINE TO CANADIAN LINE. BETTER CHANCES FOR PRECIPITATION ARE
EXPECTED THIS AFTERNOON, ESPECIALLY NORTH OF A BOYS RANCH TO
WELLINGTON LINE. SHOWERS AND EVEN A THUNDERSTORM CAN`T EVEN BE RULED
OUT AHEAD OF THE COLD FRONT THIS AFTERNOON. THROUGH 4 PM, WE THINK
THE PRECIPITATION TYPE ACROSS THE ENTIRE AREA WILL REMAIN ALL LIQUID.
HOWEVER, IF THE COLDER AIR ARRIVES SOONER, A CHANGEOVER TO SNOW WOULD
OCCUR, BUT THE CHANCE OF THIS LOOKS MOST LIKELY TO OCCUR ACROSS THE
FAR NORTHWEST. COLDER AIR IS EXPECTED TO FILTER INTO THE PANHANDLES
FROM NORTH TO SOUTH AFTER 4 PM. AS THIS OCCURS, THE PRECIPITATION
WILL QUICKLY TRANSITION TO SNOW, ESPECIALLY NORTH OF A DALHART TO
CANADIAN LINE. AFTER 7 PM, ANY PRECIPITATION IS EXPECTED TO BE
CONFINED NORTH OF A ROMERO TO CLAUDE LINE. THE HIGHEST CHANCES OF
PRECIPITATION, ESPECIALLY SNOW, LOOK TO BE NORTH OF A TEXLINE TO
ALLISON LINE. MODELS AGREE THAT MESOSCALE PROCESS WILL BE FAVORABLE
FOR A QUICK 1 TO 2 INCHES OF SNOW (WITH AN ISOLATED AMOUNT UP TO 4
INCHES) TO ACCUMULATE ACROSS THE OKLAHOMA PANHANDLE AND THE NORTHERN
TEXAS PANHANDLE BETWEEN 4 PM AND 11 PM. HOWEVER, THE MODELS DISAGREE
ON EXACTLY WHERE THE STRONGEST MESOSCALE FORCING WILL SET UP, BUT WE
BASED OUR FORECAST MORE HEAVILY ON THE RAP AND NAM, WHICH SUGGEST THE
HEAVIEST TOTALS WILL OCCUR ACROSS THE NORTHWEST PANHANDLES. IN
ADDITION TO THE SNOW, STRONG NORTHERLY WINDS WILL CREATE BLOWING
SNOW, WHICH WILL RESULT IN NEAR WHITEOUT CONDITIONS. FOR THESE
REASONS, WE HAVE ISSUED A WINTER WEATHER ADVISORY FOR THIS AFTERNOON
AND EVENING, GENERALLY NORTH OF A DALHART TO CANADIAN LINE. THE SNOW
WILL TAPER OFF PRETTY QUICKLY BY MIDNIGHT WITH ONLY A FEW FLURRIES
LINGERING ACROSS THE FAR NORTHEAST AFTER 1 AM.
TEMPERATURES: OUR CONFIDENCE IN HIGHS FOR TODAY IS PRETTY LOW AND
WILL ALL DEPEND ON THE TIMING OF THE COLD FRONT. FOR NOW, WE EXPECT
HIGHS TO RANGE FROM THE LOWER 40S IN THE NORTH TO LOWER 60S IN THE
SOUTH. TEMPERATURES WILL BE QUITE COLD TONIGHT WITH LOWS RANGING FROM
THE LOWER TEENS INT HE NORTHWEST TO THE UPPER 20S IN THE SOUTHEAST.
SUNDAY-SUNDAY NIGHT: COOL CONDITIONS ARE EXPECTED WITH HIGHS ONLY
CLIMBING INTO THE UPPER 30S IN THE NORTHWEST TO UPPER 40S IN THE
SOUTHEAST. SOME LIGHT SNOW WILL BE POSSIBLE SUNDAY NIGHT ACROSS THE
NORTHWEST, BUT SNOW ACCUMULATIONS WILL BE LESS THAN A FEW TENTHS OF
AN INCH DUE DRY AIR NEAR THE SURFACE. LOW TEMPERATURES COULD BE CLOSE
RECORDS SUNDAY NIGHT.
MONDAY-MONDAY NIGHT: CONTINUED COOL TEMPERATURES WILL PERSIST DUE TO
NORTHWEST FLOW ALOFT AND SURFACE WINDS REMAINING FROM A
PREDOMINANTLY UPSLOPE DIRECTION. SOME FLURRIES WILL REMAIN POSSIBLE
ACROSS THE WESTERN AND NORTHWESTERN AREAS, BUT NO ACCUMULATIONS ARE
EXPECTED.
TUESDAY-SATURDAY: TEMPERATURES WILL REBOUND TUESDAY AND ESPECIALLY
INTO WEDNESDAY AS A ZONAL FLOW ALOFT DEVELOPS. TEMPERATURES COULD BE
PROBLEMATIC AT THE END OF THE WEEK AS A COUPLE OF COLD FRONTS MAY PUSH
THROUGH THE AREA.
JACKSON
FIRE WEATHER...
CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED GENERALLY SOUTH AND
WEST OF A CHANNING TO AMARILLO TO CLAUDE LINE THIS AFTERNOON AS
RELATIVE HUMIDITY VALUES DROP BETWEEN 8 AND 15 PERCENT AND WESTERLY
20 FOOT WINDS WILL INCREASE BETWEEN 25 AND 35 MPH WITH HIGHER GUSTS.
FIRE PERSONNEL SHOULD BE AWARE THAT A COLD FRONT WILL MOVE THROUGH
THE AREA LATE THIS AFTERNOON AND SHIFT WINDS TO THE NORTH WITH
SPEEDS REMAINING BETWEEN 15 AND 35 MPH OVERNIGHT. ALTHOUGH FUELS ARE
STILL MARGINAL FOR LARGE WILDFIRE SPREAD ACROSS THE AREA, THE
STRENGTH OF THE WINDS MAY BE ABLE TO OFFSET THE MARGINAL FUELS ENOUGH
TO RAISE THE WILDFIRE THREAT THIS AFTERNOON. ADDITIONALLY, THE CORE
OF THE 500 MB WINDS AND 850 MB THERMAL RIDGE WILL BE LOCATED ACROSS
OUR WESTERN AND SOUTHWESTERN AREAS. FOR THESE REASONS, WE ELECTED TO
ISSUE A RED FLAG WARNING FOR THIS AFTERNOON. WITH THE PASSAGE OF THE
COLD FRONT...RELATIVE HUMIDITY VALUES WILL QUICKLY RISE ABOVE 15
PERCENT.
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...WINTER WEATHER ADVISORY UNTIL 1 AM CDT SUNDAY FOR THE FOLLOWING
ZONES: DALLAM...HANSFORD...HEMPHILL...HUTCHINSON...
LIPSCOMB...OCHILTREE...ROBERTS...SHERMAN.
WIND ADVISORY UNTIL 1 AM CDT SUNDAY FOR THE FOLLOWING ZONES:
ARMSTRONG...CARSON...COLLINGSWORTH...DONLEY...GRAY...
HANSFORD...HEMPHILL...HUTCHINSON...LIPSCOMB...OCHILTREE...
ROBERTS...SHERMAN...WHEELER.
HIGH WIND WARNING UNTIL 1 AM CDT SUNDAY FOR THE FOLLOWING ZONES:
DALLAM...DEAF SMITH...HARTLEY...MOORE...OLDHAM...POTTER...
RANDALL.
RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: ARMSTRONG...DEAF SMITH...HARTLEY...OLDHAM...POTTER...
RANDALL.
OK...WINTER WEATHER ADVISORY UNTIL 1 AM CDT SUNDAY FOR THE FOLLOWING
ZONES: BEAVER...CIMARRON...TEXAS.
WIND ADVISORY UNTIL 1 AM CDT SUNDAY FOR THE FOLLOWING ZONES:
BEAVER...CIMARRON...TEXAS.
&&
$$
05/16
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
106 PM CDT SAT MAR 23 2013
.AVIATION...
/18Z TAFS/ LOW CONFIDENCE FORECAST ESPECIALLY OVER THE FIRST 9 HOURS
OF THE FORECAST PERIOD. CURRENT SFC ANALYSIS INDICATES A SURFACE LOW
OVER EASTERN NM WITH A COLD FRONT OVER THE OK PANHANDLE. THIS FRONT
WILL CONTINUE TO SLIDE SOUTH DURING THE AFTERNOON WHILE THE SURFACE
TROUGH SLIDES TO THE SOUTHEAST. DESPITE THE RELATIVELY LIGHT AND
VARIABLE WINDS THIS MORNING...EXPECT WINDS TO STRENGTHEN BY LATE THIS
AFTERNOON WITH SUSTAINED WINDS QUICKLY RAMPING UP TO AROUND 25-30 KTS
WITH GUSTS UP TO 40 KTS DUE TO THE COMBINATION OF A TIGHT PRESSURE
GRADIENT AND STRONG PRESSURE RISES BEHIND THE FRONT. GIVEN THESE
PARAMETERS WILL CONTINUE WITH THE AWW FOR KAMA FROM 19Z- 05Z SUN.
THESE STRONG WINDS CAN ALSO RESULT IN AREAS OF BLOWING DUST
/PRIMARILY AT KAMA/ ALTHOUGH WITH WINDS OUT OF THE
NORTHWEST...CONFIDENCE IN THIS OCCURRING IS LOW. BY THIS
EVENING EXPECT A BAND OF -SN TO GRAZE THE KGUY/KDHT TERMINALS. HIGH-
RES MODELS SUGGEST THE -SN TO START AROUND 21Z AT KGUY AND SPREAD
SOUTH TO KDHT BY 00Z. LOOKS LIKE -SN WILL STAY NORTH OF THE KAMA
TERMINAL. ANY -SN SHOULD END BY AROUND 03Z SUN. GIVEN THE ONSET OF
-SN...EXPECT MAINLY MVFR TO LIFR CONDITIONS AT KDHT/KGUY RESPECTIVELY
WHILE KAMA SHOULD REMAIN VFR /ALTHOUGH LOW CLOUDS WITH MVFR CIGS ARE
A POSSIBIILITY OVERNIGHT/. EXPECT A GRADUAL IMPROVEMENT TO VFR AT
KGUY/KDHT SUN MORNING. STRONG AND GUSTY NORTHERLY WINDS WILL
GRADUALLY DIMINISH TO 15 KTS SUSTAINED TOWARD THE END OF THE FORECAST
PERIOD.
CLK
&&
.PREV DISCUSSION... /ISSUED 714 AM CDT SAT MAR 23 2013/
AVIATION...DISCUSSION FOR 12Z TAFS
KAMA...
BRIEF CLEARING COULD FILL BACK IN WITH A BKN MVFR DECK OVER THE NEXT
HR. THIS DECK SHOULD THEN LIFT BACK BY 15Z TO VFR CONDITIONS. STRONG
AND GUSTY WEST WINDS WILL DEVELOP THIS AFTERNOON...ESPECIALLY AFTER
20Z. THESE WINDS COULD KICK UP SOME VISIBILITY REDUCING DUST AS THEY
GUST TO NEAR 45 KTS. WINDS WILL SHIFT TO THE NW AROUND 23Z AND
CONTINUE TO GUST TO NEAR OR ABOVE 40 KTS THROUGH 02Z. AFTER
02Z...WINDS SHOULD BEGIN A SLOW WEAKENING TREND. MVFR CIGS COULD SET
BACK IN FOR A BIT TONIGHT...BUT UNCERTAINTY REMAINS TOO HIGH TO
INCLUDE.
KDHT...
WINDS SHOULD GENERALLY BE OUT THE NNW THE ENTIRE PERIOD. LIGHT WINDS
SHOULD DOMINATE THROUGH 21Z. AFTER 21Z...WINDS WILL STRENGTHEN AND
GUST TO AROUND 40 KTS. THERE COULD ALSO BE A BAND OF SNOW THAT MOVES
THROUGH LATE THIS AFTERNOON. MVFR CIGS SHOULD BE NOTED FOR A PERIOD
THIS EVENING. WINDS WILL RELAX AFTER 06Z AND VFR CONDITIONS SHOULD
TAKE OVER.
KGUY...
KGUY SHOULD STAY IN THE PROVERBIAL SOUP FOR MUCH OF THE DAY TODAY AS
HIGH END IFR OR LOW END MVFR CIGS DOMINATE. WINDS WILL START OF AN
EASTERLY DIRECTION BEFORE TURNING TO THE NORTH AND INCREASING IN
SPEED AFTER 21Z. A BAND OF SNOW COULD AFFECT THE TERMINAL BETWEEN 21Z
AND 03Z...WITH DRYING CONDITIONS NOTED AFTER 03Z. MVFR CIGS COULD
VERY WELL HANG ON THROUGH SATURDAY NIGHT AT KGUY.
SIMPSON
PREV DISCUSSION... /ISSUED 602 AM CDT SAT MAR 23 2013/
DISCUSSION...
TODAY-TONIGHT: LOTS OF WEATHER COMING. THAT PRETTY MUCH SUMS UP THE
FORECAST FOR TODAY AS WE EXPECT RAIN, POSSIBLY A THUNDERSTORM, SNOW,
HIGH WIND, AND DUST TO ALL BE OBSERVED ACROSS THE PANHANDLES.
WIND: A STRONG COLD FRONT IS SCHEDULED TO ENTER THE OKLAHOMA
PANHANDLE BY EARLY THIS AFTERNOON AND PUSH SOUTH OF THE TEXAS
PANHANDLE BY LATE THIS AFTERNOON. AHEAD OF THE FRONT, VERY STRONG
WESTERLY WINDS ARE EXPECTED TO DEVELOP BETWEEN 3 AND 4 PM, ESPECIALLY
ACROSS THE WESTERN TEXAS PANHANDLE WHERE A FEW ISOLATED WIND GUSTS UP
TO 60 MPH WILL BE POSSIBLE. NOT VERY CONFIDENT THAT ALL AREAS IN THE
HIGH WIND WARNING WILL GUST TO 60 MPH. AS THE FRONT MOVES THROUGH,
WINDS WILL SHIFT TO THE NORTH AND WILL REMAIN BETWEEN 20 AND 35 MPH
OVERNIGHT AT ALL LOCATIONS. IF THE COLD FRONT ARRIVES SOONER THAN
FORECAST, THE THREAT FOR HIGH WINDS WILL BE GREATLY DIMINISHED.
DUST: DUE TO THE STRONG WESTERLY WINDS, BLOWING DUST WILL MOVE INTO
OUR AREA FROM EASTERN NEW MEXICO THIS AFTERNOON AND WILL LIKELY
IMPACT LOCATIONS SOUTH AND WEST OF A DALHART TO BORGER TO CLAUDE
LINE. VISIBILITIES COULD BE REDUCED TO LESS THAN 2 MILES, ESPECIALLY
ACROSS DEAF SMITH COUNTY.
PRECIPITATION CHANCES: DRIZZLE IS EXPECTED THIS MORNING NORTH OF A
TEXLINE TO CANADIAN LINE. BETTER CHANCES FOR PRECIPITATION ARE
EXPECTED THIS AFTERNOON, ESPECIALLY NORTH OF A BOYS RANCH TO
WELLINGTON LINE. SHOWERS AND EVEN A THUNDERSTORM CAN`T EVEN BE RULED
OUT AHEAD OF THE COLD FRONT THIS AFTERNOON. THROUGH 4 PM, WE THINK
THE PRECIPITATION TYPE ACROSS THE ENTIRE AREA WILL REMAIN ALL LIQUID.
HOWEVER, IF THE COLDER AIR ARRIVES SOONER, A CHANGEOVER TO SNOW WOULD
OCCUR, BUT THE CHANCE OF THIS LOOKS MOST LIKELY TO OCCUR ACROSS THE
FAR NORTHWEST. COLDER AIR IS EXPECTED TO FILTER INTO THE PANHANDLES
FROM NORTH TO SOUTH AFTER 4 PM. AS THIS OCCURS, THE PRECIPITATION
WILL QUICKLY TRANSITION TO SNOW, ESPECIALLY NORTH OF A DALHART TO
CANADIAN LINE. AFTER 7 PM, ANY PRECIPITATION IS EXPECTED TO BE
CONFINED NORTH OF A ROMERO TO CLAUDE LINE. THE HIGHEST CHANCES OF
PRECIPITATION, ESPECIALLY SNOW, LOOK TO BE NORTH OF A TEXLINE TO
ALLISON LINE. MODELS AGREE THAT MESOSCALE PROCESS WILL BE FAVORABLE
FOR A QUICK 1 TO 2 INCHES OF SNOW (WITH AN ISOLATED AMOUNT UP TO 4
INCHES) TO ACCUMULATE ACROSS THE OKLAHOMA PANHANDLE AND THE NORTHERN
TEXAS PANHANDLE BETWEEN 4 PM AND 11 PM. HOWEVER, THE MODELS DISAGREE
ON EXACTLY WHERE THE STRONGEST MESOSCALE FORCING WILL SET UP, BUT WE
BASED OUR FORECAST MORE HEAVILY ON THE RAP AND NAM, WHICH SUGGEST THE
HEAVIEST TOTALS WILL OCCUR ACROSS THE NORTHWEST PANHANDLES. IN
ADDITION TO THE SNOW, STRONG NORTHERLY WINDS WILL CREATE BLOWING
SNOW, WHICH WILL RESULT IN NEAR WHITEOUT CONDITIONS. FOR THESE
REASONS, WE HAVE ISSUED A WINTER WEATHER ADVISORY FOR THIS AFTERNOON
AND EVENING, GENERALLY NORTH OF A DALHART TO CANADIAN LINE. THE SNOW
WILL TAPER OFF PRETTY QUICKLY BY MIDNIGHT WITH ONLY A FEW FLURRIES
LINGERING ACROSS THE FAR NORTHEAST AFTER 1 AM.
TEMPERATURES: OUR CONFIDENCE IN HIGHS FOR TODAY IS PRETTY LOW AND
WILL ALL DEPEND ON THE TIMING OF THE COLD FRONT. FOR NOW, WE EXPECT
HIGHS TO RANGE FROM THE LOWER 40S IN THE NORTH TO LOWER 60S IN THE
SOUTH. TEMPERATURES WILL BE QUITE COLD TONIGHT WITH LOWS RANGING FROM
THE LOWER TEENS INT HE NORTHWEST TO THE UPPER 20S IN THE SOUTHEAST.
SUNDAY-SUNDAY NIGHT: COOL CONDITIONS ARE EXPECTED WITH HIGHS ONLY
CLIMBING INTO THE UPPER 30S IN THE NORTHWEST TO UPPER 40S IN THE
SOUTHEAST. SOME LIGHT SNOW WILL BE POSSIBLE SUNDAY NIGHT ACROSS THE
NORTHWEST, BUT SNOW ACCUMULATIONS WILL BE LESS THAN A FEW TENTHS OF
AN INCH DUE DRY AIR NEAR THE SURFACE. LOW TEMPERATURES COULD BE CLOSE
RECORDS SUNDAY NIGHT.
MONDAY-MONDAY NIGHT: CONTINUED COOL TEMPERATURES WILL PERSIST DUE TO
NORTHWEST FLOW ALOFT AND SURFACE WINDS REMAINING FROM A
PREDOMINANTLY UPSLOPE DIRECTION. SOME FLURRIES WILL REMAIN POSSIBLE
ACROSS THE WESTERN AND NORTHWESTERN AREAS, BUT NO ACCUMULATIONS ARE
EXPECTED.
TUESDAY-SATURDAY: TEMPERATURES WILL REBOUND TUESDAY AND ESPECIALLY
INTO WEDNESDAY AS A ZONAL FLOW ALOFT DEVELOPS. TEMPERATURES COULD BE
PROBLEMATIC AT THE END OF THE WEEK AS A COUPLE OF COLD FRONTS MAY PUSH
THROUGH THE AREA.
JACKSON
FIRE WEATHER...
CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED GENERALLY SOUTH AND
WEST OF A CHANNING TO AMARILLO TO CLAUDE LINE THIS AFTERNOON AS
RELATIVE HUMIDITY VALUES DROP BETWEEN 8 AND 15 PERCENT AND WESTERLY
20 FOOT WINDS WILL INCREASE BETWEEN 25 AND 35 MPH WITH HIGHER GUSTS.
FIRE PERSONNEL SHOULD BE AWARE THAT A COLD FRONT WILL MOVE THROUGH
THE AREA LATE THIS AFTERNOON AND SHIFT WINDS TO THE NORTH WITH
SPEEDS REMAINING BETWEEN 15 AND 35 MPH OVERNIGHT. ALTHOUGH FUELS ARE
STILL MARGINAL FOR LARGE WILDFIRE SPREAD ACROSS THE AREA, THE
STRENGTH OF THE WINDS MAY BE ABLE TO OFFSET THE MARGINAL FUELS ENOUGH
TO RAISE THE WILDFIRE THREAT THIS AFTERNOON. ADDITIONALLY, THE CORE
OF THE 500 MB WINDS AND 850 MB THERMAL RIDGE WILL BE LOCATED ACROSS
OUR WESTERN AND SOUTHWESTERN AREAS. FOR THESE REASONS, WE ELECTED TO
ISSUE A RED FLAG WARNING FOR THIS AFTERNOON. WITH THE PASSAGE OF THE
COLD FRONT...RELATIVE HUMIDITY VALUES WILL QUICKLY RISE ABOVE 15
PERCENT.
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...WINTER WEATHER ADVISORY UNTIL 1 AM CDT SUNDAY FOR THE FOLLOWING
ZONES: DALLAM...HANSFORD...HEMPHILL...HUTCHINSON...
LIPSCOMB...OCHILTREE...ROBERTS...SHERMAN.
WIND ADVISORY UNTIL 1 AM CDT SUNDAY FOR THE FOLLOWING ZONES:
ARMSTRONG...CARSON...COLLINGSWORTH...DONLEY...GRAY...
HANSFORD...HEMPHILL...HUTCHINSON...LIPSCOMB...OCHILTREE...
ROBERTS...SHERMAN...WHEELER.
HIGH WIND WARNING UNTIL 1 AM CDT SUNDAY FOR THE FOLLOWING ZONES:
DALLAM...DEAF SMITH...HARTLEY...MOORE...OLDHAM...POTTER...
RANDALL.
RED FLAG WARNING UNTIL 8 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: ARMSTRONG...DEAF SMITH...HARTLEY...OLDHAM...POTTER...
RANDALL.
OK...WINTER WEATHER ADVISORY UNTIL 1 AM CDT SUNDAY FOR THE FOLLOWING
ZONES: BEAVER...CIMARRON...TEXAS.
WIND ADVISORY UNTIL 1 AM CDT SUNDAY FOR THE FOLLOWING ZONES:
BEAVER...CIMARRON...TEXAS.
&&
$$
05/16
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1253 PM CDT SAT MAR 23 2013
.DISCUSSION...SEE AVIATION SECTION FOR 18Z TAFS.
&&
.AVIATION...COLD FRONT BOUNDARY HAS MOVED SOUTH TO NEAR A
COTULLA TO ALICE TO CORPUS CHRISTI TO JUST OFFSHORE OF PORT
O`CONNOR. VFR CONDITIONS EXIST OVER THE BRUSH COUNTRY WHILE
STRATUS HOLDS OVER THE COASTAL PLAINS ESPECIALLY IN THE
POST-FRONTAL REGION WHERE LIFR CIGS/IFR VSBYS WILL HOLD
UNTIL MID-AFTERNOON. EXPECT CLOUDS WILL SCATTER OUT AT VCT
BY LATE AFTERNOON WITH VFR PREVALENT ACROSS SOUTH TEXAS
INTO MID EVENING. SOUTHEAST WINDS WILL BRING BACK LOW LEVEL
MOISTURE INTO COASTAL PLAINS WITH A BRIEF PERIOD OF FOG
AND LOW STRATUS DEVELOPING BETWEEN 05-09Z WITH IFR/LIFR
CONDS EXPECTED. THE COLD FRONT WILL SURGE THROUGH SOUTH
TEXAS BETWEEN 09Z-12Z WITH A BRIEF PERIOD OF MVFR CIGS
POST-FRONTAL OVER THE COASTAL PLAINS. THEN CLEARING SKIES
AND VERY GUSTY NORTH WINDS AS HIGH PRESSURE BUILDS SOUTH
AFTER 13-14Z SUNDAY.
&&
.PREV DISCUSSION... /ISSUED 912 AM CDT SAT MAR 23 2013/
DISCUSSION...THE HI RES MODELS SEEM TO HAVE BEEN CORRECT WITH
REGARDS TO THE COLD FRONT THIS MORNING. THE COLD FRONT HAS PUSHED
SOUTH OF A PORT LAVACA TO BEEVILLE TO UVALDE LINE AS OF 14Z. THE
LATEST HI RES MODELS ALONG WITH 12Z RUC SHOW THIS BOUNDARY WILL
CONTINUE TO SLOWLY SAG SOUTHWARD INTO THE COASTAL WATERS BY 18Z.
THIS WILL SERIOUSLY AFFECT HIGH TEMPS ACROSS THE NORTHEAST AREAS
TODAY AND HAVE LOWERED SIFNIFICANTLY IN THE VICTORIA AREA AND MAY
NOT HAVE LOWERED THEM ENOUGH...BUT CLOSE TO 06Z NAM/00Z ARW.
WILL MAINTAIN SLIGHT CHANCE OF ELEVATED CONVECTION OCCURRING
IN THE VICTORIA CROSSROADS AS WELL. THIS FRONT WILL AFFECT THE
EASTWARD PROGRESSION OF DRYLINE AND VERY WARM TEMPS OVER THE
BRUSH COUNTRY ALONG WITH CORRESPONDING INCREASE IN WINDS. WILL
STILL SHOW GUSTY NORTHWEST WINDS OVER THE WESTERN BRUSH COUNTRY.
MARINE...AREAS OF DENSE SEA FOG HAVE FORMED OVER THE NEARSHORE
WATERS INTO THE BAYS. VISIBILITES AT PORT ARANSAS AND NORTH BEACH
HAVE LOWERED TO NEAR A QUARTER OF A MILE WITH ROCKPORT DOWN TO
AROUND 1 MILE. ISSUED DENSE FOG ADVISORY FOR BAYS AND NEARSHORE
WATERS UNTIL 18Z. WINDS SHOULD SHIFT TO NORTH WITH THE FRONT
MOVING INTO THE AREA BY THEN WITH CORRESPONDING IMPROVEMENT IN
VISIBILITIES.
FIRE WEATHER...CONCERNED THAT RED FLAG WARNING FOR TODAY WILL
NOT VERIFY BUT FOR ONLY THE WESTERN PART OF WEBB COUNTY DUE TO
SOUTHWARD ADVANCE OF COLD FRONT INTO THE COASTAL PLAINS. ELEVATED
FIRE WEATHER CONDITIONS ARE EXPECTED AS FAR EAST AS HIGHWAY 16
SO WILL KEEP RED FLAG WARNING AS IS FOR NOW FOR TODAY...NO CHANGES
FOR SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 86 53 71 46 68 / 10 10 0 10 10
VICTORIA 75 47 67 38 65 / 20 10 0 10 10
LAREDO 99 56 75 45 73 / 10 10 0 10 10
ALICE 88 51 71 41 69 / 10 10 0 10 10
ROCKPORT 77 51 69 49 67 / 20 10 0 10 10
COTULLA 91 45 72 39 70 / 10 10 0 10 10
KINGSVILLE 88 53 72 45 69 / 10 10 0 10 10
NAVY CORPUS 79 55 71 51 68 / 10 10 0 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...RED FLAG WARNING FROM 9 AM TO 8 PM CDT SUNDAY FOR THE FOLLOWING
ZONES: ARANSAS...BEE...CALHOUN...DUVAL...GOLIAD...JIM
WELLS...KLEBERG...LA SALLE...LIVE OAK...MCMULLEN...NUECES...
REFUGIO...SAN PATRICIO...VICTORIA...WEBB.
RED FLAG WARNING UNTIL 7 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: DUVAL...LA SALLE...MCMULLEN...WEBB.
GM...GALE WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON FOR THE
FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT
ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT
O`CONNOR...COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS
OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA
SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY TO PORT
ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS TO
MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM.
DENSE FOG ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR THE
FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT
ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT
O`CONNOR...COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS
OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA
SHIP CHANNEL OUT 20 NM.
&&
$$
TT/89...AVIATION
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1223 PM CDT SAT MAR 23 2013
.AVIATION...
COOL WITH IFR OVERCAST SKIES PREVAILED AT KCDS EARLY THIS
AFTERNOON...AND WILL LIKELY PERSIST FOR THE NEXT FEW HOURS BEFORE
FINALLY CLEARING OUT. MEANWHILE...VFR CONDITIONS OCCURRED AT KLBB.
LATE THIS AFTERNOON...WNW WINDS WILL INCREASE TO 26-30KTS AT BOTH
TAF SITES...WITH HIGHEST SPEEDS AT KLBB. AS SUCH...VFR TO IFR VISIBILITY
RESTRICTIONS WILL OCCUR AT KCDS AND KLBB RESPECTIVELY. THIS
EVENING...BLDU WILL EASE BUT WINDS WILL VEER TO THE NW AND REMAIN
STRONG /23-30KTS/ WITH STRONGEST SPEEDS ONCE AGAIN AT KLBB. WE
HAVE AN AWW IN EFFECT FOR KLBB FROM 23/00Z-24/05Z. HAVE MAINTAINED
VFR BLDU AT KLBB DUE TO THE ANTICIPATED STRONG WINDS BEHIND THE
FRONT UNTIL 24/05Z. COMPUTER MODELS HINT AT THE RETURN OF MVFR
CLOUD DECKS AT KCDS THIS EVENING...BUT LIFTING TO VFR TONIGHT.
TOMORROW MORNING-AFTERNOON...SLIGHTLY BREEZY NRLY WINDS WILL
ENSUE OTHERWISE VFR WILL PREVAIL.
&&
PREV DISCUSSION... /ISSUED 446 AM CDT SAT MAR 23 2013/
SHORT TERM...
BUSY WEATHER DAY TODAY HIGHLIGHTED BY STRONG WIND...BLOWING DUST AND
CRITICAL FIRE WEATHER.
THE STORM SYSTEM THAT WILL BRING THE HIGH IMPACT WEATHER TO WEST
TEXAS IS AN ENERGETIC SHORTWAVE TROUGH THAT IS CURRENTLY DIVING
THROUGH THE ROCKIES AND WILL EMERGE ACROSS THE CENTRAL/SOUTHERN HIGH
PLAINS LATE TODAY. IN ADVANCE OF THE SYSTEM...COOL AND MOIST UPSLOPE
FLOW CURRENTLY DOMINATES THE FA...AND WE COULD EVEN SEE SOME PATCHY
FOG DEVELOP IN ADDITION TO AREAS OF LOW CLOUDS EARLY THIS MORNING.
ALSO...ELEVATED WAA DRIVEN SHOWERS/STORMS MAY FLIRT WITH THE FAR
SOUTHEAST ZONES TO AROUND OR SHORTLY AFTER 12Z. HOWEVER...THINGS WILL
BE CHANGING...PARTICULARLY THIS AFTERNOON AND EVENING...AS THE
STORM SYSTEM APPROACHES FROM THE NORTHWEST.
AT THE SFC...A TROUGH/DRYLINE WILL PROGRESS FROM WEST TO EAST ACROSS
THE CAPROCK...WITH DRY AND INCREASINGLY STRONG WESTERLY WINDS
DEVELOPING IN ITS WAKE. THERE REMAINS SOME UNCERTAINTY WITH EXACTLY
HOW FAR EAST THIS WARM/DRY/WINDY AIR WILL ADVANCE...WITH THE RAP AND
NAM SUGGESTING THE SFC RIDGING WILL HOLD STRONG ACROSS THE FAR
EASTERN ZONES...THUS HOLDING THE WINDS AND TEMPERATURES DOWN AND
KEEPING THE MOISTURE LEVEL UP THERE. THIS SEEMS PLAUSIBLE GIVEN THE
SLIGHTLY SLOWER APPROACH OF THE UPPER-LEVEL STORM. ELSEWHERE...THE
STRONG WESTERLY WINDS WILL QUICKLY ADVANCE ACROSS THE CAPROCK
THROUGH THE MIDDLE AND LATE AFTERNOON HOURS. EXPECT SOLID WIND
ADVISORY FOR SPOTS ON THE CAPROCK BY LATE AFTERNOON. GIVEN THE
SLOWER EASTWARD PROGRESS OF THE UPPER TROUGH...STRONG DEEP
SUBSIDENCE WILL BE DELAYED A BIT...WHICH BRINGS SOME UNCERTAINTY
TO JUST HOW EFFICIENTLY THE STRONGER WINDS ALOFT WILL MIX DOWN TO
THE SFC. STILL...GIVEN DECENT AGREEMENT IN THE NWP THAT A 40+ KT
850 MB JET WILL TRANSLATE FROM EASTERN NM TOWARD OUR FAR
NORTHWESTERN ZONES FROM MID-TO LATE AFTERNOON...HAVE DECIDED TO
UPGRADE THE SOUTHWESTERN PANHANDLE FROM A WIND ADVISORY TO A HIGH
WIND WARNING. THESE STRONG WINDS WILL LOFT PLENTY OF BLOWING DUST
AND COMBINED WITH VERY DRY AIR WILL RESULT IN CRITICAL FIRE
WEATHER FOR MUCH OF THE FA. WE DID DECIDE TO TRIM THE WIND
ADVISORY ACROSS THE SOUTHEASTERN MOST ZONES THROUGH 00Z...WHERE
THE SFC RIDGING WILL LIKELY HELP KEEP WINDS DOWN.
THEN...LATE THIS AFTERNOON INTO THIS EVENING...A STRONG COLD FRONT
WILL PLUNGE SOUTHWARD THROUGH THE CWA. A TIGHT PRESSURE GRADIENT
COUPLED WITH PROGGED 3 HOUR PRESSURE RISES OF 10-13 MB IMMEDIATELY
IN THE WAKE OF THE FRONT RAISE CONCERNS FOR VERY STRONG WINDS BEHIND
THIS FRONT. HENCE...WE ARE MAINTAINING ALL WIND HIGHLIGHTS THROUGH
05Z...WHILE EXPANDING THE WIND ADVISORY TO INCLUDE THE FAR EASTERN
ZONES IN THE 00-05Z TIMEFRAME. THERE IS SOME CONCERN THE ADDED
ISALLOBARIC COMPONENT TO THE WINDS COULD PUSH WINDS INTO HIGH WIND
TERRITORY OVER MUCH/ALL OF THE CAPROCK AS THE FRONT MOVES THROUGH
THIS EVENING...BUT WILL ALLOW LATER SHIFTS TO EVALUATE AND DECIDE IF
AN UPGRADE MAY BE NEEDED. THIS FRONT COULD ALSO INITIALLY
ENHANCE/FOCUS THE DUST...THOUGH VISIBILITIES SHOULD THEN GRADUALLY
IMPROVE AND WINDS SLOWLY DECREASE IN THE WAKE OF THE FRONT LATE THIS
EVENING/TONIGHT AS THE PRESSURE GRADIENT SLOWLY RELAXES. LARGE-SCALE
LIFT WILL ALSO GRAZE BY TO THE NORTH THIS EVENING AND A BRIEF SHOWER
IS NOT COMPLETELY OUT OF THE QUESTION TOWARD CHILDRESS.
EXPECT RELATIVELY MILD CONDITIONS TODAY...WITH HIGHS RANGING FROM
NEAR 60 DEGREES ACROSS THE NORTHWEST ZONES TO NEAR 80S FROM SPUR TO
JAYTON...WITH SLIGHTLY COOLER CONDITIONS FURTHER EAST FROM THERE.
CHILLY AIR WILL ADVECT IN TONIGHT BEHIND THE FRONT SUPPLYING LOWS IN
THE TEENS NORTHWEST...WITH 20S COMMON OVER MUCH OF THE REMAINDER OF
THE AREA.
LONG TERM...
SHARPLY COOLER TEMPERATURES ARE EXPECTED ON MONDAY AS COOL AIR
FLOWS SOUTH ON THE BACK SIDE OF THE DEPARTING TROUGH. ERN ZONES
MAY SEE A INCREASE IN NORTHERLY WINDS AFTER SUNRISE AS STRONGER
WINDS ON THE TAIL END OF THE CYCLONIC CIRCULATION MIX DOWN BUT
WINDS IN GENERAL WILL TREND DOWNWARD THROUGH THE DAY...BECOMING
LIGHT BY EVENING. MOSTLY CLEAR SKIES WILL COUNTER THE COLD AIR
ADVECTION TO A DEGREE AND HIGHS ARE EXPECTED TO REACH THE MIDDLE
40S...WITH SOME LOWER 50S IN THE SOUTH. ON MONDAY...AS WEAK
TRAILING DISTURBANCE WILL SLIDE SE OUT OF COLO INTO THE
PANHANDLES...BRIEFLY ENHANCING THE UPSLOPE FLOW...AND LIKELY
GENERATING SOME LIGHT SNOW SHOWERS ACROSS NE NM MONDAY MORNING.
IT IS NOT OUT OF THE QUESTION THAT SOME LIGHT SHOWERS COULD MAKE
AS FAR AS THE SW TX PANHANDLE AND WE HAVE MAINTAINED A VERY LOW
CHANCE /10 PERCENT/ OF NON-ACCUMULATING FLURRIES. OTHERWISE...WITH
COOL-SFC RIDGING PERSISTING AND SOME MID-LVL CLOUD COVER
ACCOMPANYING THE PASSING WAVE...WE DON/T EXPECT A GREAT DEAL OF
MODERATING OF TEMPS...ONLY A SLIGHT WARMING IN THE UPPER 40S/LOWER
50S. BY TUESDAY...SFC RIDGING WILL SHIFT EAST AND LEE TROUGHING
WILL COMMENCE AS UPPER FLOW TENDS TO BECOME MORE ZONAL. HIGHS
LIKELY TO WARM INTO THE 50S FOR TUESDAY.
THE WARMING TREND WILL PICK UP STEAM WED INTO THU AS UPPER FLOW BECOMES
BROADLY CYCLONIC DOWNSTREAM OF A TROUGH APPROACHING THE WEST
COAST. LOW-LVL MOISTURE RETURN WILL ALSO BEGIN ACROSS TX AND COULD
REACH OUR SRN ZONES BY THURSDAY EVENING.
MEDIUM-RANGE GUIDANCE BEGINS TO DIFFER ON THE EVOLUTION OF A CLOSED
LOW TAKING SHAPE OVER SRN CALIFORNIA LATE WEEK INTO NEXT WEEKEND ALONG
WITH THE DEVELOPMENT AND POSITION OF A DRYLINE DEVELOPING ACROSS
WEST TEXAS. THE FIRST OPPORTUNITY FOR PRECIP MAY ARRIVE FRIDAY
EVENING IF THE DRYLINE HOLDS NEAR THE CAPROCK. THEN NEXT WEEKEND
OR EARLY THE FOLLOWING WEEK...AS THE UPPER LOW EJECTS AND WITH THE
POSSIBILITY OF A COLD FRONT MOVING INTO THE AREA...THERE MAY BE A
PERIOD IN THERE OF SOME HIGHER PRECIP CHANCES. LOW CONFIDENCE IN
THE DETAILS KEEPS THE FORECAST DRY FOR NOW.
FIRE WEATHER...
COOL AND MOIST CONDITIONS WERE GREETING THE SOUTH PLAINS REGION
EARLY THIS MORNING. HOWEVER...VERY DRY AIR AND MILD CONDITIONS
WILL OVERSPREAD THE CAPROCK INTO THE WESTERN ROLLING PLAINS THIS
AFTERNOON...ON STRONG WESTERLY WINDS. EXPECT RH VALUES TO FALL
WELL BELOW 10 PERCENT...TO AS LOW AS 5 PERCENT OVER MUCH OF THE
CAPROCK AND INTO THE WESTERN ROLLING PLAINS AS SUSTAINED WESTERLY
WINDS INCREASE TO 25 TO 35 MPH AT 20 FT. THIS WILL RESULT IN A
PROLONGED PERIOD OF RED FLAG CONDITIONS...AND A RED FLAG WARNING
REMAINS IN EFFECT FOR ALL BUT THE SOUTHEAST TEXAS PANHANDLE FROM
18Z THROUGH 3Z. THERE IS SOME UNCERTAINTY IF THE STRONG WINDS AND
DRY AIR WILL ADVANCE INTO THE FAR EASTERN EXTENT OF THE CURRENT
RED FLAG WARNING...BUT HAVE CHOSEN TO MAINTAIN AS IS FOR NOW. A
STRONG COLD FRONT WILL THEN RACE FROM NORTH TO SOUTH ACROSS THE
SOUTH PLAINS THIS EVENING...BRINGING AN ABRUPT NORTHERLY WIND
SHIFT AND CONTINUED VERY STRONG WINDS. THIS WIND SHIFT WILL
COMPLICATE ANY ONGOING FIRE FIGHTING EFFORTS. THE NORTHERLY WINDS
WILL ONLY SLOWLY DECREASE THROUGH THE OVERNIGHT HOURS...THOUGH RH
VALUES WILL STEADILY CLIMB BEHIND THE FRONT.
THE FORECAST WEATHER PATTERN OF DRY WESTERLY MID-TROPOSPHERIC
FLOW AND BREEZY SOUTH TO SOUTHWEST WINDS AT THE SURFACE IN THE
DAYTIME HOURS MAY FAVOR SOME FIRE WX CONCERNS ACROSS WESTERN
AREAS DURING THE WED THROUGH SAT TIME-FRAME.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 19 42 19 41 22 / 10 0 10 10 10
TULIA 22 42 21 41 25 / 10 0 10 10 10
PLAINVIEW 23 44 22 42 26 / 10 0 0 10 10
LEVELLAND 21 46 23 47 26 / 10 0 0 10 10
LUBBOCK 24 46 24 47 27 / 10 0 0 10 0
DENVER CITY 24 48 26 50 28 / 0 0 0 10 0
BROWNFIELD 23 48 26 49 28 / 0 0 0 10 0
CHILDRESS 28 47 25 48 29 / 10 10 0 10 0
SPUR 29 49 26 47 28 / 10 0 0 0 0
ASPERMONT 31 50 28 50 31 / 10 0 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 10 PM CDT THIS EVENING FOR THE FOLLOWING
ZONES: TXZ021>024-027>031-033>044.
WIND ADVISORY UNTIL MIDNIGHT CDT TONIGHT FOR THE FOLLOWING
ZONES: TXZ023-024-029>031-033>037-039>043.
HIGH WIND WARNING UNTIL MIDNIGHT CDT TONIGHT FOR THE FOLLOWING
ZONES: TXZ021-022-027-028.
WIND ADVISORY FROM 7 PM THIS EVENING TO MIDNIGHT CDT TONIGHT FOR
THE FOLLOWING ZONES: TXZ025-026-032-038-044.
&&
$$
29
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
912 AM CDT SAT MAR 23 2013
.DISCUSSION...THE HI RES MODELS SEEM TO HAVE BEEN CORRECT WITH
REGARDS TO THE COLD FRONT THIS MORNING. THE COLD FRONT HAS PUSHED
SOUTH OF A PORT LAVACA TO BEEVILLE TO UVALDE LINE AS OF 14Z. THE
LATEST HI RES MODELS ALONG WITH 12Z RUC SHOW THIS BOUNDARY WILL
CONTINUE TO SLOWLY SAG SOUTHWARD INTO THE COASTAL WATERS BY 18Z.
THIS WILL SERIOUSLY AFFECT HIGH TEMPS ACROSS THE NORTHEAST AREAS
TODAY AND HAVE LOWERED SIFNIFICANTLY IN THE VICTORIA AREA AND MAY
NOT HAVE LOWERED THEM ENOUGH...BUT CLOSE TO 06Z NAM/00Z ARW.
WILL MAINTAIN SLIGHT CHANCE OF ELEVATED CONVECTION OCCURRING
IN THE VICTORIA CROSSROADS AS WELL. THIS FRONT WILL AFFECT THE
EASTWARD PROGRESSION OF DRYLINE AND VERY WARM TEMPS OVER THE
BRUSH COUNTRY ALONG WITH CORRESPONDING INCREASE IN WINDS. WILL
STILL SHOW GUSTY NORTHWEST WINDS OVER THE WESTERN BRUSH COUNTRY.
&&
.MARINE...AREAS OF DENSE SEA FOG HAVE FORMED OVER THE NEARSHORE
WATERS INTO THE BAYS. VISIBILITES AT PORT ARANSAS AND NORTH BEACH
HAVE LOWERED TO NEAR A QUARTER OF A MILE WITH ROCKPORT DOWN TO
AROUND 1 MILE. ISSUED DENSE FOG ADVISORY FOR BAYS AND NEARSHORE
WATERS UNTIL 18Z. WINDS SHOULD SHIFT TO NORTH WITH THE FRONT
MOVING INTO THE AREA BY THEN WITH CORRESPONDING IMPROVEMENT IN
VISIBILITIES.
&&
.FIRE WEATHER...CONCERNED THAT RED FLAG WARNING FOR TODAY WILL
NOT VERIFY BUT FOR ONLY THE WESTERN PART OF WEBB COUNTY DUE TO
SOUTHWARD ADVANCE OF COLD FRONT INTO THE COASTAL PLAINS. ELEVATED
FIRE WEATHER CONDITIONS ARE EXPECTED AS FAR EAST AS HIGHWAY 16
SO WILL KEEP RED FLAG WARNING AS IS FOR NOW FOR TODAY...NO CHANGES
FOR SUNDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 86 53 71 46 68 / 10 10 0 10 10
VICTORIA 75 47 67 38 65 / 20 10 0 10 10
LAREDO 99 56 75 45 73 / 10 10 0 10 10
ALICE 88 51 71 41 69 / 10 10 0 10 10
ROCKPORT 77 51 69 49 67 / 20 10 0 10 10
COTULLA 91 45 72 39 70 / 10 10 0 10 10
KINGSVILLE 88 53 72 45 69 / 10 10 0 10 10
NAVY CORPUS 79 55 71 51 68 / 10 10 0 10 10
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...RED FLAG WARNING FROM 9 AM TO 8 PM CDT SUNDAY FOR THE FOLLOWING
ZONES: ARANSAS...BEE...CALHOUN...DUVAL...GOLIAD...JIM
WELLS...KLEBERG...LA SALLE...LIVE OAK...MCMULLEN...NUECES...
REFUGIO...SAN PATRICIO...VICTORIA...WEBB.
RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 7 PM CDT THIS
EVENING FOR THE FOLLOWING ZONES: DUVAL...LA SALLE...
MCMULLEN...WEBB.
GM...GALE WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON FOR THE
FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT
ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT
O`CONNOR...COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS
OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA
SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY TO PORT
ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS TO
MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM.
DENSE FOG ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR THE
FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT
ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT
O`CONNOR...COASTAL WATERS FROM BAFFIN BAY TO PORT ARANSAS
OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO MATAGORDA
SHIP CHANNEL OUT 20 NM.
&&
$$
TMT/89...SHORT TERM
AREA FORECAST DISCUSSION
NWS AMARILLO TX
714 AM CDT SAT MAR 23 2013
.AVIATION...DISCUSSION FOR 12Z TAFS
KAMA...
BRIEF CLEARING COULD FILL BACK IN WITH A BKN MVFR DECK OVER THE NEXT
HR. THIS DECK SHOULD THEN LIFT BACK BY 15Z TO VFR CONDITIONS. STRONG
AND GUSTY WEST WINDS WILL DEVELOP THIS AFTERNOON...ESPECIALLY AFTER
20Z. THESE WINDS COULD KICK UP SOME VISIBILITY REDUCING DUST AS THEY
GUST TO NEAR 45 KTS. WINDS WILL SHIFT TO THE NW AROUND 23Z AND
CONTINUE TO GUST TO NEAR OR ABOVE 40 KTS THROUGH 02Z. AFTER
02Z...WINDS SHOULD BEGIN A SLOW WEAKENING TREND. MVFR CIGS COULD SET
BACK IN FOR A BIT TONIGHT...BUT UNCERTAINTY REMAINS TOO HIGH TO
INCLUDE.
KDHT...
WINDS SHOULD GENERALLY BE OUT THE NNW THE ENTIRE PERIOD. LIGHT WINDS
SHOULD DOMINATE THROUGH 21Z. AFTER 21Z...WINDS WILL STRENGTHEN AND
GUST TO AROUND 40 KTS. THERE COULD ALSO BE A BAND OF SNOW THAT MOVES
THROUGH LATE THIS AFTERNOON. MVFR CIGS SHOULD BE NOTED FOR A PERIOD
THIS EVENING. WINDS WILL RELAX AFTER 06Z AND VFR CONDITIONS SHOULD
TAKE OVER.
KGUY...
KGUY SHOULD STAY IN THE PROVERBIAL SOUP FOR MUCH OF THE DAY TODAY AS
HIGH END IFR OR LOW END MVFR CIGS DOMINATE. WINDS WILL START OF AN
EASTERLY DIRECTION BEFORE TURNING TO THE NORTH AND INCREASING IN
SPEED AFTER 21Z. A BAND OF SNOW COULD AFFECT THE TERMINAL BETWEEN 21Z
AND 03Z...WITH DRYING CONDITIONS NOTED AFTER 03Z. MVFR CIGS COULD
VERY WELL HANG ON THROUGH SATURDAY NIGHT AT KGUY.
SIMPSON
&&
.PREV DISCUSSION... /ISSUED 602 AM CDT SAT MAR 23 2013/
DISCUSSION...
TODAY-TONIGHT: LOTS OF WEATHER COMING. THAT PRETTY MUCH SUMS UP THE
FORECAST FOR TODAY AS WE EXPECT RAIN, POSSIBLY A THUNDERSTORM, SNOW,
HIGH WIND, AND DUST TO ALL BE OBSERVED ACROSS THE PANHANDLES.
WIND: A STRONG COLD FRONT IS SCHEDULED TO ENTER THE OKLAHOMA
PANHANDLE BY EARLY THIS AFTERNOON AND PUSH SOUTH OF THE TEXAS
PANHANDLE BY LATE THIS AFTERNOON. AHEAD OF THE FRONT, VERY STRONG
WESTERLY WINDS ARE EXPECTED TO DEVELOP BETWEEN 3 AND 4 PM, ESPECIALLY
ACROSS THE WESTERN TEXAS PANHANDLE WHERE A FEW ISOLATED WIND GUSTS UP
TO 60 MPH WILL BE POSSIBLE. NOT VERY CONFIDENT THAT ALL AREAS IN THE
HIGH WIND WARNING WILL GUST TO 60 MPH. AS THE FRONT MOVES THROUGH,
WINDS WILL SHIFT TO THE NORTH AND WILL REMAIN BETWEEN 20 AND 35 MPH
OVERNIGHT AT ALL LOCATIONS. IF THE COLD FRONT ARRIVES SOONER THAN
FORECAST, THE THREAT FOR HIGH WINDS WILL BE GREATLY DIMINISHED.
DUST: DUE TO THE STRONG WESTERLY WINDS, BLOWING DUST WILL MOVE INTO
OUR AREA FROM EASTERN NEW MEXICO THIS AFTERNOON AND WILL LIKELY
IMPACT LOCATIONS SOUTH AND WEST OF A DALHART TO BORGER TO CLAUDE
LINE. VISIBILITIES COULD BE REDUCED TO LESS THAN 2 MILES, ESPECIALLY
ACROSS DEAF SMITH COUNTY.
PRECIPITATION CHANCES: DRIZZLE IS EXPECTED THIS MORNING NORTH OF A
TEXLINE TO CANADIAN LINE. BETTER CHANCES FOR PRECIPITATION ARE
EXPECTED THIS AFTERNOON, ESPECIALLY NORTH OF A BOYS RANCH TO
WELLINGTON LINE. SHOWERS AND EVEN A THUNDERSTORM CAN`T EVEN BE RULED
OUT AHEAD OF THE COLD FRONT THIS AFTERNOON. THROUGH 4 PM, WE THINK
THE PRECIPITATION TYPE ACROSS THE ENTIRE AREA WILL REMAIN ALL LIQUID.
HOWEVER, IF THE COLDER AIR ARRIVES SOONER, A CHANGEOVER TO SNOW WOULD
OCCUR, BUT THE CHANCE OF THIS LOOKS MOST LIKELY TO OCCUR ACROSS THE
FAR NORTHWEST. COLDER AIR IS EXPECTED TO FILTER INTO THE PANHANDLES
FROM NORTH TO SOUTH AFTER 4 PM. AS THIS OCCURS, THE PRECIPITATION
WILL QUICKLY TRANSITION TO SNOW, ESPECIALLY NORTH OF A DALHART TO
CANADIAN LINE. AFTER 7 PM, ANY PRECIPITATION IS EXPECTED TO BE
CONFINED NORTH OF A ROMERO TO CLAUDE LINE. THE HIGHEST CHANCES OF
PRECIPITATION, ESPECIALLY SNOW, LOOK TO BE NORTH OF A TEXLINE TO
ALLISON LINE. MODELS AGREE THAT MESOSCALE PROCESS WILL BE FAVORABLE
FOR A QUICK 1 TO 2 INCHES OF SNOW (WITH AN ISOLATED AMOUNT UP TO 4
INCHES) TO ACCUMULATE ACROSS THE OKLAHOMA PANHANDLE AND THE NORTHERN
TEXAS PANHANDLE BETWEEN 4 PM AND 11 PM. HOWEVER, THE MODELS DISAGREE
ON EXACTLY WHERE THE STRONGEST MESOSCALE FORCING WILL SET UP, BUT WE
BASED OUR FORECAST MORE HEAVILY ON THE RAP AND NAM, WHICH SUGGEST THE
HEAVIEST TOTALS WILL OCCUR ACROSS THE NORTHWEST PANHANDLES. IN
ADDITION TO THE SNOW, STRONG NORTHERLY WINDS WILL CREATE BLOWING
SNOW, WHICH WILL RESULT IN NEAR WHITEOUT CONDITIONS. FOR THESE
REASONS, WE HAVE ISSUED A WINTER WEATHER ADVISORY FOR THIS AFTERNOON
AND EVENING, GENERALLY NORTH OF A DALHART TO CANADIAN LINE. THE SNOW
WILL TAPER OFF PRETTY QUICKLY BY MIDNIGHT WITH ONLY A FEW FLURRIES
LINGERING ACROSS THE FAR NORTHEAST AFTER 1 AM.
TEMPERATURES: OUR CONFIDENCE IN HIGHS FOR TODAY IS PRETTY LOW AND
WILL ALL DEPEND ON THE TIMING OF THE COLD FRONT. FOR NOW, WE EXPECT
HIGHS TO RANGE FROM THE LOWER 40S IN THE NORTH TO LOWER 60S IN THE
SOUTH. TEMPERATURES WILL BE QUITE COLD TONIGHT WITH LOWS RANGING FROM
THE LOWER TEENS INT HE NORTHWEST TO THE UPPER 20S IN THE SOUTHEAST.
SUNDAY-SUNDAY NIGHT: COOL CONDITIONS ARE EXPECTED WITH HIGHS ONLY
CLIMBING INTO THE UPPER 30S IN THE NORTHWEST TO UPPER 40S IN THE
SOUTHEAST. SOME LIGHT SNOW WILL BE POSSIBLE SUNDAY NIGHT ACROSS THE
NORTHWEST, BUT SNOW ACCUMULATIONS WILL BE LESS THAN A FEW TENTHS OF
AN INCH DUE DRY AIR NEAR THE SURFACE. LOW TEMPERATURES COULD BE CLOSE
RECORDS SUNDAY NIGHT.
MONDAY-MONDAY NIGHT: CONTINUED COOL TEMPERATURES WILL PERSIST DUE TO
NORTHWEST FLOW ALOFT AND SURFACE WINDS REMAINING FROM A
PREDOMINANTLY UPSLOPE DIRECTION. SOME FLURRIES WILL REMAIN POSSIBLE
ACROSS THE WESTERN AND NORTHWESTERN AREAS, BUT NO ACCUMULATIONS ARE
EXPECTED.
TUESDAY-SATURDAY: TEMPERATURES WILL REBOUND TUESDAY AND ESPECIALLY
INTO WEDNESDAY AS A ZONAL FLOW ALOFT DEVELOPS. TEMPERATURES COULD BE
PROBLEMATIC AT THE END OF THE WEEK AS A COUPLE OF COLD FRONTS MAY PUSH
THROUGH THE AREA.
JACKSON
FIRE WEATHER...
CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED GENERALLY SOUTH AND
WEST OF A CHANNING TO AMARILLO TO CLAUDE LINE THIS AFTERNOON AS
RELATIVE HUMIDITY VALUES DROP BETWEEN 8 AND 15 PERCENT AND WESTERLY
20 FOOT WINDS WILL INCREASE BETWEEN 25 AND 35 MPH WITH HIGHER GUSTS.
FIRE PERSONNEL SHOULD BE AWARE THAT A COLD FRONT WILL MOVE THROUGH
THE AREA LATE THIS AFTERNOON AND SHIFT WINDS TO THE NORTH WITH
SPEEDS REMAINING BETWEEN 15 AND 35 MPH OVERNIGHT. ALTHOUGH FUELS ARE
STILL MARGINAL FOR LARGE WILDFIRE SPREAD ACROSS THE AREA, THE
STRENGTH OF THE WINDS MAY BE ABLE TO OFFSET THE MARGINAL FUELS ENOUGH
TO RAISE THE WILDFIRE THREAT THIS AFTERNOON. ADDITIONALLY, THE CORE
OF THE 500 MB WINDS AND 850 MB THERMAL RIDGE WILL BE LOCATED ACROSS
OUR WESTERN AND SOUTHWESTERN AREAS. FOR THESE REASONS, WE ELECTED TO
ISSUE A RED FLAG WARNING FOR THIS AFTERNOON. WITH THE PASSAGE OF THE
COLD FRONT...RELATIVE HUMIDITY VALUES WILL QUICKLY RISE ABOVE 15
PERCENT.
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 1 AM CDT
SUNDAY FOR THE FOLLOWING ZONES: DALLAM...HANSFORD...
HEMPHILL...HUTCHINSON...LIPSCOMB...OCHILTREE...ROBERTS...
SHERMAN.
WIND ADVISORY FROM 3 PM THIS AFTERNOON TO 1 AM CDT SUNDAY FOR
THE FOLLOWING ZONES: ARMSTRONG...CARSON...COLLINGSWORTH...
DONLEY...GRAY...HANSFORD...HEMPHILL...HUTCHINSON...
LIPSCOMB...OCHILTREE...ROBERTS...SHERMAN...WHEELER.
HIGH WIND WARNING FROM 3 PM THIS AFTERNOON TO 1 AM CDT SUNDAY
FOR THE FOLLOWING ZONES: DALLAM...DEAF SMITH...HARTLEY...
MOORE...OLDHAM...POTTER...RANDALL.
RED FLAG WARNING FROM 3 PM THIS AFTERNOON TO 8 PM CDT THIS
EVENING FOR THE FOLLOWING ZONES: ARMSTRONG...DEAF SMITH...
HARTLEY...OLDHAM...POTTER...RANDALL.
OK...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 1 AM CDT
SUNDAY FOR THE FOLLOWING ZONES: BEAVER...CIMARRON...TEXAS.
WIND ADVISORY FROM 3 PM THIS AFTERNOON TO 1 AM CDT SUNDAY FOR
THE FOLLOWING ZONES: BEAVER...CIMARRON...TEXAS.
&&
$$
09/13
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
704 AM CDT SAT MAR 23 2013
.AVIATION...
COOL AND MOIST AIRMASS WAS CURRENTLY BRINGING MVFR VISIBILITIES TO
KLBB AND MVFR CIGS TO KCDS EARLY THIS MORNING. EITHER SITE COULD
SEE A PERIOD OF IFR CIGS/BR EARLY...THOUGH HAVE FAVORED THE LESS
PESSIMISTIC CONDITIONS IN THE TAF. MUCH DRIER AIR WILL SPREAD INTO
KLBB BY MID TO LATE MORNING WITH STRONG WESTERLY WINDS DEVELOPING
THIS AFTERNOON AT KLBB...THOUGH KCDS MAY STAY IN LIGHTER...MOISTER
EASTERLY FLOW THROUGH MUCH/ALL OF THE DAY. WESTERLY WINDS AT KLBB
WILL LIKELY BECOME SUSTAIN A0A 30 KNOTS AROUND MID-AFTERNOON. A
STRONG FROPA WILL AFFECT THE TERMINALS THIS EVENING SHIFTING THE
WINDS TO THE NORTH AND KEEPING THE WINDS ELEVATED...BEFORE THEY
SLOWLY DECREASE LATE TONIGHT. THE STRONGEST WINDS LATE THIS
AFTERNOON AND EARLY THIS EVENING WILL LOFT PLENTY OF BLOWING DUST
AND HAVE MAINTAINED MVFR VISIBILITIES AT KLBB...THOUGH THEY COULD
FALL EVEN LOWER FOR SHORTER PERIODS DEPENDING ON THE EXACT
FETCH AND MAGNITUDE OF THE WINDS. IN ADDITION...AN AWW HAS BEEN
ISSUED FOR KLBB FROM 20Z-05Z FOR THE STRONG WINDS. MVFR
CIGS...PERHAPS EVEN A SHOWER...COULD AFFECT KCDS BEHIND THE FRONT
THIS EVENING.
&&
.PREV DISCUSSION... /ISSUED 446 AM CDT SAT MAR 23 2013/
SHORT TERM...
BUSY WEATHER DAY TODAY HIGHLIGHTED BY STRONG WIND...BLOWING DUST AND
CRITICAL FIRE WEATHER.
THE STORM SYSTEM THAT WILL BRING THE HIGH IMPACT WEATHER TO WEST
TEXAS IS AN ENERGETIC SHORTWAVE TROUGH THAT IS CURRENTLY DIVING
THROUGH THE ROCKIES AND WILL EMERGE ACROSS THE CENTRAL/SOUTHERN HIGH
PLAINS LATE TODAY. IN ADVANCE OF THE SYSTEM...COOL AND MOIST UPSLOPE
FLOW CURRENTLY DOMINATES THE FA...AND WE COULD EVEN SEE SOME PATCHY
FOG DEVELOP IN ADDITION TO AREAS OF LOW CLOUDS EARLY THIS MORNING.
ALSO...ELEVATED WAA DRIVEN SHOWERS/STORMS MAY FLIRT WITH THE FAR
SOUTHEAST ZONES TO AROUND OR SHORTLY AFTER 12Z. HOWEVER...THINGS WILL
BE CHANGING...PARTICULARLY THIS AFTERNOON AND EVENING...AS THE
STORM SYSTEM APPROACHES FROM THE NORTHWEST.
AT THE SFC...A TROUGH/DRYLINE WILL PROGRESS FROM WEST TO EAST ACROSS
THE CAPROCK...WITH DRY AND INCREASINGLY STRONG WESTERLY WINDS
DEVELOPING IN ITS WAKE. THERE REMAINS SOME UNCERTAINTY WITH EXACTLY
HOW FAR EAST THIS WARM/DRY/WINDY AIR WILL ADVANCE...WITH THE RAP AND
NAM SUGGESTING THE SFC RIDGING WILL HOLD STRONG ACROSS THE FAR
EASTERN ZONES...THUS HOLDING THE WINDS AND TEMPERATURES DOWN AND
KEEPING THE MOISTURE LEVEL UP THERE. THIS SEEMS PLAUSIBLE GIVEN THE
SLIGHTLY SLOWER APPROACH OF THE UPPER-LEVEL STORM. ELSEWHERE...THE
STRONG WESTERLY WINDS WILL QUICKLY ADVANCE ACROSS THE CAPROCK
THROUGH THE MIDDLE AND LATE AFTERNOON HOURS. EXPECT SOLID WIND
ADVISORY FOR SPOTS ON THE CAPROCK BY LATE AFTERNOON. GIVEN THE
SLOWER EASTWARD PROGRESS OF THE UPPER TROUGH...STRONG DEEP
SUBSIDENCE WILL BE DELAYED A BIT...WHICH BRINGS SOME UNCERTAINTY
TO JUST HOW EFFICIENTLY THE STRONGER WINDS ALOFT WILL MIX DOWN TO
THE SFC. STILL...GIVEN DECENT AGREEMENT IN THE NWP THAT A 40+ KT
850 MB JET WILL TRANSLATE FROM EASTERN NM TOWARD OUR FAR
NORTHWESTERN ZONES FROM MID-TO LATE AFTERNOON...HAVE DECIDED TO
UPGRADE THE SOUTHWESTERN PANHANDLE FROM A WIND ADVISORY TO A HIGH
WIND WARNING. THESE STRONG WINDS WILL LOFT PLENTY OF BLOWING DUST
AND COMBINED WITH VERY DRY AIR WILL RESULT IN CRITICAL FIRE
WEATHER FOR MUCH OF THE FA. WE DID DECIDE TO TRIM THE WIND
ADVISORY ACROSS THE SOUTHEASTERN MOST ZONES THROUGH 00Z...WHERE
THE SFC RIDGING WILL LIKELY HELP KEEP WINDS DOWN.
THEN...LATE THIS AFTERNOON INTO THIS EVENING...A STRONG COLD FRONT
WILL PLUNGE SOUTHWARD THROUGH THE CWA. A TIGHT PRESSURE GRADIENT
COUPLED WITH PROGGED 3 HOUR PRESSURE RISES OF 10-13 MB IMMEDIATELY
IN THE WAKE OF THE FRONT RAISE CONCERNS FOR VERY STRONG WINDS BEHIND
THIS FRONT. HENCE...WE ARE MAINTAINING ALL WIND HIGHLIGHTS THROUGH
05Z...WHILE EXPANDING THE WIND ADVISORY TO INCLUDE THE FAR EASTERN
ZONES IN THE 00-05Z TIMEFRAME. THERE IS SOME CONCERN THE ADDED
ISALLOBARIC COMPONENT TO THE WINDS COULD PUSH WINDS INTO HIGH WIND
TERRITORY OVER MUCH/ALL OF THE CAPROCK AS THE FRONT MOVES THROUGH
THIS EVENING...BUT WILL ALLOW LATER SHIFTS TO EVALUATE AND DECIDE IF
AN UPGRADE MAY BE NEEDED. THIS FRONT COULD ALSO INITIALLY
ENHANCE/FOCUS THE DUST...THOUGH VISIBILITIES SHOULD THEN GRADUALLY
IMPROVE AND WINDS SLOWLY DECREASE IN THE WAKE OF THE FRONT LATE THIS
EVENING/TONIGHT AS THE PRESSURE GRADIENT SLOWLY RELAXES. LARGE-SCALE
LIFT WILL ALSO GRAZE BY TO THE NORTH THIS EVENING AND A BRIEF SHOWER
IS NOT COMPLETELY OUT OF THE QUESTION TOWARD CHILDRESS.
EXPECT RELATIVELY MILD CONDITIONS TODAY...WITH HIGHS RANGING FROM
NEAR 60 DEGREES ACROSS THE NORTHWEST ZONES TO NEAR 80S FROM SPUR TO
JAYTON...WITH SLIGHTLY COOLER CONDITIONS FURTHER EAST FROM THERE.
CHILLY AIR WILL ADVECT IN TONIGHT BEHIND THE FRONT SUPPLYING LOWS IN
THE TEENS NORTHWEST...WITH 20S COMMON OVER MUCH OF THE REMAINDER OF
THE AREA.
LONG TERM...
SHARPLY COOLER TEMPERATURES ARE EXPECTED ON MONDAY AS COOL AIR
FLOWS SOUTH ON THE BACK SIDE OF THE DEPARTING TROUGH. ERN ZONES
MAY SEE A INCREASE IN NORTHERLY WINDS AFTER SUNRISE AS STRONGER
WINDS ON THE TAIL END OF THE CYCLONIC CIRCULATION MIX DOWN BUT
WINDS IN GENERAL WILL TREND DOWNWARD THROUGH THE DAY...BECOMING
LIGHT BY EVENING. MOSTLY CLEAR SKIES WILL COUNTER THE COLD AIR
ADVECTION TO A DEGREE AND HIGHS ARE EXPECTED TO REACH THE MIDDLE
40S...WITH SOME LOWER 50S IN THE SOUTH. ON MONDAY...AS WEAK
TRAILING DISTURBANCE WILL SLIDE SE OUT OF COLO INTO THE
PANHANDLES...BRIEFLY ENHANCING THE UPSLOPE FLOW...AND LIKELY
GENERATING SOME LIGHT SNOW SHOWERS ACROSS NE NM MONDAY MORNING.
IT IS NOT OUT OF THE QUESTION THAT SOME LIGHT SHOWERS COULD MAKE
AS FAR AS THE SW TX PANHANDLE AND WE HAVE MAINTAINED A VERY LOW
CHANCE /10 PERCENT/ OF NON-ACCUMULATING FLURRIES. OTHERWISE...WITH
COOL-SFC RIDGING PERSISTING AND SOME MID-LVL CLOUD COVER
ACCOMPANYING THE PASSING WAVE...WE DON/T EXPECT A GREAT DEAL OF
MODERATING OF TEMPS...ONLY A SLIGHT WARMING IN THE UPPER 40S/LOWER
50S. BY TUESDAY...SFC RIDGING WILL SHIFT EAST AND LEE TROUGHING
WILL COMMENCE AS UPPER FLOW TENDS TO BECOME MORE ZONAL. HIGHS
LIKELY TO WARM INTO THE 50S FOR TUESDAY.
THE WARMING TREND WILL PICK UP STEAM WED INTO THU AS UPPER FLOW BECOMES
BROADLY CYCLONIC DOWNSTREAM OF A TROUGH APPROACHING THE WEST
COAST. LOW-LVL MOISTURE RETURN WILL ALSO BEGIN ACROSS TX AND COULD
REACH OUR SRN ZONES BY THURSDAY EVENING.
MEDIUM-RANGE GUIDANCE BEGINS TO DIFFER ON THE EVOLUTION OF A CLOSED
LOW TAKING SHAPE OVER SRN CALIFORNIA LATE WEEK INTO NEXT WEEKEND ALONG
WITH THE DEVELOPMENT AND POSITION OF A DRYLINE DEVELOPING ACROSS
WEST TEXAS. THE FIRST OPPORTUNITY FOR PRECIP MAY ARRIVE FRIDAY
EVENING IF THE DRYLINE HOLDS NEAR THE CAPROCK. THEN NEXT WEEKEND
OR EARLY THE FOLLOWING WEEK...AS THE UPPER LOW EJECTS AND WITH THE
POSSIBILITY OF A COLD FRONT MOVING INTO THE AREA...THERE MAY BE A
PERIOD IN THERE OF SOME HIGHER PRECIP CHANCES. LOW CONFIDENCE IN
THE DETAILS KEEPS THE FORECAST DRY FOR NOW.
FIRE WEATHER...
COOL AND MOIST CONDITIONS WERE GREETING THE SOUTH PLAINS REGION
EARLY THIS MORNING. HOWEVER...VERY DRY AIR AND MILD CONDITIONS
WILL OVERSPREAD THE CAPROCK INTO THE WESTERN ROLLING PLAINS THIS
AFTERNOON...ON STRONG WESTERLY WINDS. EXPECT RH VALUES TO FALL
WELL BELOW 10 PERCENT...TO AS LOW AS 5 PERCENT OVER MUCH OF THE
CAPROCK AND INTO THE WESTERN ROLLING PLAINS AS SUSTAINED WESTERLY
WINDS INCREASE TO 25 TO 35 MPH AT 20 FT. THIS WILL RESULT IN A
PROLONGED PERIOD OF RED FLAG CONDITIONS...AND A RED FLAG WARNING
REMAINS IN EFFECT FOR ALL BUT THE SOUTHEAST TEXAS PANHANDLE FROM
18Z THROUGH 3Z. THERE IS SOME UNCERTAINTY IF THE STRONG WINDS AND
DRY AIR WILL ADVANCE INTO THE FAR EASTERN EXTENT OF THE CURRENT
RED FLAG WARNING...BUT HAVE CHOSEN TO MAINTAIN AS IS FOR NOW. A
STRONG COLD FRONT WILL THEN RACE FROM NORTH TO SOUTH ACROSS THE
SOUTH PLAINS THIS EVENING...BRINGING AN ABRUPT NORTHERLY WIND
SHIFT AND CONTINUED VERY STRONG WINDS. THIS WIND SHIFT WILL
COMPLICATE ANY ONGOING FIRE FIGHTING EFFORTS. THE NORTHERLY WINDS
WILL ONLY SLOWLY DECREASE THROUGH THE OVERNIGHT HOURS...THOUGH RH
VALUES WILL STEADILY CLIMB BEHIND THE FRONT.
THE FORECAST WEATHER PATTERN OF DRY WESTERLY MID-TROPOSPHERIC
FLOW AND BREEZY SOUTH TO SOUTHWEST WINDS AT THE SURFACE IN THE
DAYTIME HOURS MAY FAVOR SOME FIRE WX CONCERNS ACROSS WESTERN
AREAS DURING THE WED THROUGH SAT TIME-FRAME.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 59 19 42 19 41 / 0 10 0 10 10
TULIA 66 22 42 21 41 / 10 10 0 10 10
PLAINVIEW 68 23 44 22 42 / 10 10 0 0 10
LEVELLAND 69 21 46 23 47 / 0 10 0 0 10
LUBBOCK 71 24 46 24 47 / 0 10 0 0 10
DENVER CITY 72 24 48 26 50 / 0 0 0 0 10
BROWNFIELD 73 23 48 26 49 / 0 0 0 0 10
CHILDRESS 66 28 47 25 48 / 10 10 10 0 10
SPUR 79 29 49 26 47 / 10 10 0 0 0
ASPERMONT 76 31 50 28 50 / 10 10 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 10 PM CDT THIS
EVENING FOR THE FOLLOWING ZONES: TXZ021>024-027>031-033>044.
WIND ADVISORY FROM 1 PM THIS AFTERNOON TO MIDNIGHT CDT TONIGHT
FOR THE FOLLOWING ZONES: TXZ023-024-029>031-033>037-039>043.
HIGH WIND WARNING FROM 1 PM THIS AFTERNOON TO MIDNIGHT CDT
TONIGHT FOR THE FOLLOWING ZONES: TXZ021-022-027-028.
WIND ADVISORY FROM 7 PM THIS EVENING TO MIDNIGHT CDT TONIGHT FOR
THE FOLLOWING ZONES: TXZ025-026-032-038-044.
&&
$$
23/33/23
AREA FORECAST DISCUSSION
NWS AMARILLO TX
602 AM CDT SAT MAR 23 2013
.DISCUSSION...
TODAY-TONIGHT: LOTS OF WEATHER COMING. THAT PRETTY MUCH SUMS UP THE
FORECAST FOR TODAY AS WE EXPECT RAIN, POSSIBLY A THUNDERSTORM, SNOW,
HIGH WIND, AND DUST TO ALL BE OBSERVED ACROSS THE PANHANDLES.
WIND: A STRONG COLD FRONT IS SCHEDULED TO ENTER THE OKLAHOMA
PANHANDLE BY EARLY THIS AFTERNOON AND PUSH SOUTH OF THE TEXAS
PANHANDLE BY LATE THIS AFTERNOON. AHEAD OF THE FRONT, VERY STRONG
WESTERLY WINDS ARE EXPECTED TO DEVELOP BETWEEN 3 AND 4 PM, ESPECIALLY
ACROSS THE WESTERN TEXAS PANHANDLE WHERE A FEW ISOLATED WIND GUSTS UP
TO 60 MPH WILL BE POSSIBLE. NOT VERY CONFIDENT THAT ALL AREAS IN THE
HIGH WIND WARNING WILL GUST TO 60 MPH. AS THE FRONT MOVES THROUGH,
WINDS WILL SHIFT TO THE NORTH AND WILL REMAIN BETWEEN 20 AND 35 MPH
OVERNIGHT AT ALL LOCATIONS. IF THE COLD FRONT ARRIVES SOONER THAN
FORECAST, THE THREAT FOR HIGH WINDS WILL BE GREATLY DIMINISHED.
DUST: DUE TO THE STRONG WESTERLY WINDS, BLOWING DUST WILL MOVE INTO
OUR AREA FROM EASTERN NEW MEXICO THIS AFTERNOON AND WILL LIKELY
IMPACT LOCATIONS SOUTH AND WEST OF A DALHART TO BORGER TO CLAUDE
LINE. VISIBILITIES COULD BE REDUCED TO LESS THAN 2 MILES, ESPECIALLY
ACROSS DEAF SMITH COUNTY.
PRECIPITATION CHANCES: DRIZZLE IS EXPECTED THIS MORNING NORTH OF A
TEXLINE TO CANADIAN LINE. BETTER CHANCES FOR PRECIPITATION ARE
EXPECTED THIS AFTERNOON, ESPECIALLY NORTH OF A BOYS RANCH TO
WELLINGTON LINE. SHOWERS AND EVEN A THUNDERSTORM CAN`T EVEN BE RULED
OUT AHEAD OF THE COLD FRONT THIS AFTERNOON. THROUGH 4 PM, WE THINK
THE PRECIPITATION TYPE ACROSS THE ENTIRE AREA WILL REMAIN ALL LIQUID.
HOWEVER, IF THE COLDER AIR ARRIVES SOONER, A CHANGEOVER TO SNOW WOULD
OCCUR, BUT THE CHANCE OF THIS LOOKS MOST LIKELY TO OCCUR ACROSS THE
FAR NORTHWEST. COLDER AIR IS EXPECTED TO FILTER INTO THE PANHANDLES
FROM NORTH TO SOUTH AFTER 4 PM. AS THIS OCCURS, THE PRECIPITATION
WILL QUICKLY TRANSITION TO SNOW, ESPECIALLY NORTH OF A DALHART TO
CANADIAN LINE. AFTER 7 PM, ANY PRECIPITATION IS EXPECTED TO BE
CONFINED NORTH OF A ROMERO TO CLAUDE LINE. THE HIGHEST CHANCES OF
PRECIPITATION, ESPECIALLY SNOW, LOOK TO BE NORTH OF A TEXLINE TO
ALLISON LINE. MODELS AGREE THAT MESOSCALE PROCESS WILL BE FAVORABLE
FOR A QUICK 1 TO 2 INCHES OF SNOW (WITH AN ISOLATED AMOUNT UP TO 4
INCHES) TO ACCUMULATE ACROSS THE OKLAHOMA PANHANDLE AND THE NORTHERN
TEXAS PANHANDLE BETWEEN 4 PM AND 11 PM. HOWEVER, THE MODELS DISAGREE
ON EXACTLY WHERE THE STRONGEST MESOSCALE FORCING WILL SET UP, BUT WE
BASED OUR FORECAST MORE HEAVILY ON THE RAP AND NAM, WHICH SUGGEST THE
HEAVIEST TOTALS WILL OCCUR ACROSS THE NORTHWEST PANHANDLES. IN
ADDITION TO THE SNOW, STRONG NORTHERLY WINDS WILL CREATE BLOWING
SNOW, WHICH WILL RESULT IN NEAR WHITEOUT CONDITIONS. FOR THESE
REASONS, WE HAVE ISSUED A WINTER WEATHER ADVISORY FOR THIS AFTERNOON
AND EVENING, GENERALLY NORTH OF A DALHART TO CANADIAN LINE. THE SNOW
WILL TAPER OFF PRETTY QUICKLY BY MIDNIGHT WITH ONLY A FEW FLURRIES
LINGERING ACROSS THE FAR NORTHEAST AFTER 1 AM.
TEMPERATURES: OUR CONFIDENCE IN HIGHS FOR TODAY IS PRETTY LOW AND
WILL ALL DEPEND ON THE TIMING OF THE COLD FRONT. FOR NOW, WE EXPECT
HIGHS TO RANGE FROM THE LOWER 40S IN THE NORTH TO LOWER 60S IN THE
SOUTH. TEMPERATURES WILL BE QUITE COLD TONIGHT WITH LOWS RANGING FROM
THE LOWER TEENS INT HE NORTHWEST TO THE UPPER 20S IN THE SOUTHEAST.
SUNDAY-SUNDAY NIGHT: COOL CONDITIONS ARE EXPECTED WITH HIGHS ONLY
CLIMBING INTO THE UPPER 30S IN THE NORTHWEST TO UPPER 40S IN THE
SOUTHEAST. SOME LIGHT SNOW WILL BE POSSIBLE SUNDAY NIGHT ACROSS THE
NORTHWEST, BUT SNOW ACCUMULATIONS WILL BE LESS THAN A FEW TENTHS OF
AN INCH DUE DRY AIR NEAR THE SURFACE. LOW TEMPERATURES COULD BE CLOSE
RECORDS SUNDAY NIGHT.
MONDAY-MONDAY NIGHT: CONTINUED COOL TEMPERATURES WILL PERSIST DUE TO
NORTHWEST FLOW ALOFT AND SURFACE WINDS REMAINING FROM A
PREDOMINANTLY UPSLOPE DIRECTION. SOME FLURRIES WILL REMAIN POSSIBLE
ACROSS THE WESTERN AND NORTHWESTERN AREAS, BUT NO ACCUMULATIONS ARE
EXPECTED.
TUESDAY-SATURDAY: TEMPERATURES WILL REBOUND TUESDAY AND ESPECIALLY
INTO WEDNESDAY AS A ZONAL FLOW ALOFT DEVELOPS. TEMPERATURES COULD BE
PROBLEMATIC AT THE END OF THE WEEK AS A COUPLE OF COLD FRONTS MAY PUSH
THROUGH THE AREA.
JACKSON
&&
.FIRE WEATHER...
CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED GENERALLY SOUTH AND
WEST OF A CHANNING TO AMARILLO TO CLAUDE LINE THIS AFTERNOON AS
RELATIVE HUMIDITY VALUES DROP BETWEEN 8 AND 15 PERCENT AND WESTERLY
20 FOOT WINDS WILL INCREASE BETWEEN 25 AND 35 MPH WITH HIGHER GUSTS.
FIRE PERSONNEL SHOULD BE AWARE THAT A COLD FRONT WILL MOVE THROUGH
THE AREA LATE THIS AFTERNOON AND SHIFT WINDS TO THE NORTH WITH
SPEEDS REMAINING BETWEEN 15 AND 35 MPH OVERNIGHT. ALTHOUGH FUELS ARE
STILL MARGINAL FOR LARGE WILDFIRE SPREAD ACROSS THE AREA, THE
STRENGTH OF THE WINDS MAY BE ABLE TO OFFSET THE MARGINAL FUELS ENOUGH
TO RAISE THE WILDFIRE THREAT THIS AFTERNOON. ADDITIONALLY, THE CORE
OF THE 500 MB WINDS AND 850 MB THERMAL RIDGE WILL BE LOCATED ACROSS
OUR WESTERN AND SOUTHWESTERN AREAS. FOR THESE REASONS, WE ELECTED TO
ISSUE A RED FLAG WARNING FOR THIS AFTERNOON. WITH THE PASSAGE OF THE
COLD FRONT...RELATIVE HUMIDITY VALUES WILL QUICKLY RISE ABOVE 15
PERCENT.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 62 19 41 18 41 / 10 20 0 5 5
BEAVER OK 42 21 40 20 40 / 40 60 0 5 5
BOISE CITY OK 44 15 38 14 37 / 60 60 0 20 10
BORGER TX 55 23 41 22 43 / 20 60 0 5 5
BOYS RANCH TX 61 21 44 18 43 / 20 20 0 10 5
CANYON TX 64 20 43 17 43 / 10 10 0 5 5
CLARENDON TX 61 24 44 21 45 / 10 20 0 5 5
DALHART TX 55 17 42 17 40 / 30 50 0 20 10
GUYMON OK 46 18 40 18 39 / 60 60 0 10 5
HEREFORD TX 64 19 43 16 44 / 5 10 0 5 5
LIPSCOMB TX 45 25 41 20 42 / 50 60 0 5 5
PAMPA TX 54 22 40 18 41 / 20 50 0 5 5
SHAMROCK TX 53 27 45 22 45 / 20 40 0 0 5
WELLINGTON TX 58 28 48 25 47 / 10 30 0 0 5
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 1 AM CDT
SUNDAY FOR THE FOLLOWING ZONES: DALLAM...HANSFORD...
HEMPHILL...HUTCHINSON...LIPSCOMB...OCHILTREE...ROBERTS...
SHERMAN.
WIND ADVISORY FROM 3 PM THIS AFTERNOON TO 1 AM CDT SUNDAY FOR
THE FOLLOWING ZONES: ARMSTRONG...CARSON...COLLINGSWORTH...
DONLEY...GRAY...HANSFORD...HEMPHILL...HUTCHINSON...
LIPSCOMB...OCHILTREE...ROBERTS...SHERMAN...WHEELER.
HIGH WIND WARNING FROM 3 PM THIS AFTERNOON TO 1 AM CDT SUNDAY
FOR THE FOLLOWING ZONES: DALLAM...DEAF SMITH...HARTLEY...
MOORE...OLDHAM...POTTER...RANDALL.
RED FLAG WARNING FROM 3 PM THIS AFTERNOON TO 8 PM CDT THIS
EVENING FOR THE FOLLOWING ZONES: ARMSTRONG...DEAF SMITH...
HARTLEY...OLDHAM...POTTER...RANDALL.
OK...WINTER WEATHER ADVISORY FROM 3 PM THIS AFTERNOON TO 1 AM CDT
SUNDAY FOR THE FOLLOWING ZONES: BEAVER...CIMARRON...TEXAS.
WIND ADVISORY FROM 3 PM THIS AFTERNOON TO 1 AM CDT SUNDAY FOR
THE FOLLOWING ZONES: BEAVER...CIMARRON...TEXAS.
&&
$$
BJS/JJ
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
446 AM CDT SAT MAR 23 2013
.SHORT TERM...
BUSY WEATHER DAY TODAY HIGHLIGHTED BY STRONG WIND...BLOWING DUST AND
CRITICAL FIRE WEATHER.
THE STORM SYSTEM THAT WILL BRING THE HIGH IMPACT WEATHER TO WEST
TEXAS IS AN ENERGETIC SHORTWAVE TROUGH THAT IS CURRENTLY DIVING
THROUGH THE ROCKIES AND WILL EMERGE ACROSS THE CENTRAL/SOUTHERN HIGH
PLAINS LATE TODAY. IN ADVANCE OF THE SYSTEM...COOL AND MOIST UPSLOPE
FLOW CURRENTLY DOMINATES THE FA...AND WE COULD EVEN SEE SOME PATCHY
FOG DEVELOP IN ADDITION TO AREAS OF LOW CLOUDS EARLY THIS MORNING.
ALSO...ELEVATED WAA DRIVEN SHOWERS/STORMS MAY FLIRT WITH THE FAR
SOUTHEAST ZONES TO AROUND OR SHORTLY AFTER 12Z. HOWEVER...THINGS WILL
BE CHANGING...PARTICULARLY THIS AFTERNOON AND EVENING...AS THE
STORM SYSTEM APPROACHES FROM THE NORTHWEST.
AT THE SFC...A TROUGH/DRYLINE WILL PROGRESS FROM WEST TO EAST ACROSS
THE CAPROCK...WITH DRY AND INCREASINGLY STRONG WESTERLY WINDS
DEVELOPING IN ITS WAKE. THERE REMAINS SOME UNCERTAINTY WITH EXACTLY
HOW FAR EAST THIS WARM/DRY/WINDY AIR WILL ADVANCE...WITH THE RAP AND
NAM SUGGESTING THE SFC RIDGING WILL HOLD STRONG ACROSS THE FAR
EASTERN ZONES...THUS HOLDING THE WINDS AND TEMPERATURES DOWN AND
KEEPING THE MOISTURE LEVEL UP THERE. THIS SEEMS PLAUSIBLE GIVEN THE
SLIGHTLY SLOWER APPROACH OF THE UPPER-LEVEL STORM. ELSEWHERE...THE
STRONG WESTERLY WINDS WILL QUICKLY ADVANCE ACROSS THE CAPROCK
THROUGH THE MIDDLE AND LATE AFTERNOON HOURS. EXPECT SOLID WIND
ADVISORY FOR SPOTS ON THE CAPROCK BY LATE AFTERNOON. GIVEN THE
SLOWER EASTWARD PROGRESS OF THE UPPER TROUGH...STRONG DEEP
SUBSIDENCE WILL BE DELAYED A BIT...WHICH BRINGS SOME UNCERTAINTY
TO JUST HOW EFFICIENTLY THE STRONGER WINDS ALOFT WILL MIX DOWN TO
THE SFC. STILL...GIVEN DECENT AGREEMENT IN THE NWP THAT A 40+ KT
850 MB JET WILL TRANSLATE FROM EASTERN NM TOWARD OUR FAR
NORTHWESTERN ZONES FROM MID-TO LATE AFTERNOON...HAVE DECIDED TO
UPGRADE THE SOUTHWESTERN PANHANDLE FROM A WIND ADVISORY TO A HIGH
WIND WARNING. THESE STRONG WINDS WILL LOFT PLENTY OF BLOWING DUST
AND COMBINED WITH VERY DRY AIR WILL RESULT IN CRITICAL FIRE
WEATHER FOR MUCH OF THE FA. WE DID DECIDE TO TRIM THE WIND
ADVISORY ACROSS THE SOUTHEASTERN MOST ZONES THROUGH 00Z...WHERE
THE SFC RIDGING WILL LIKELY HELP KEEP WINDS DOWN.
THEN...LATE THIS AFTERNOON INTO THIS EVENING...A STRONG COLD FRONT
WILL PLUNGE SOUTHWARD THROUGH THE CWA. A TIGHT PRESSURE GRADIENT
COUPLED WITH PROGGED 3 HOUR PRESSURE RISES OF 10-13 MB IMMEDIATELY
IN THE WAKE OF THE FRONT RAISE CONCERNS FOR VERY STRONG WINDS BEHIND
THIS FRONT. HENCE...WE ARE MAINTAINING ALL WIND HIGHLIGHTS THROUGH
05Z...WHILE EXPANDING THE WIND ADVISORY TO INCLUDE THE FAR EASTERN
ZONES IN THE 00-05Z TIMEFRAME. THERE IS SOME CONCERN THE ADDED
ISALLOBARIC COMPONENT TO THE WINDS COULD PUSH WINDS INTO HIGH WIND
TERRITORY OVER MUCH/ALL OF THE CAPROCK AS THE FRONT MOVES THROUGH
THIS EVENING...BUT WILL ALLOW LATER SHIFTS TO EVALUATE AND DECIDE IF
AN UPGRADE MAY BE NEEDED. THIS FRONT COULD ALSO INITIALLY
ENHANCE/FOCUS THE DUST...THOUGH VISIBILITIES SHOULD THEN GRADUALLY
IMPROVE AND WINDS SLOWLY DECREASE IN THE WAKE OF THE FRONT LATE THIS
EVENING/TONIGHT AS THE PRESSURE GRADIENT SLOWLY RELAXES. LARGE-SCALE
LIFT WILL ALSO GRAZE BY TO THE NORTH THIS EVENING AND A BRIEF SHOWER
IS NOT COMPLETELY OUT OF THE QUESTION TOWARD CHILDRESS.
EXPECT RELATIVELY MILD CONDITIONS TODAY...WITH HIGHS RANGING FROM
NEAR 60 DEGREES ACROSS THE NORTHWEST ZONES TO NEAR 80S FROM SPUR TO
JAYTON...WITH SLIGHTLY COOLER CONDITIONS FURTHER EAST FROM THERE.
CHILLY AIR WILL ADVECT IN TONIGHT BEHIND THE FRONT SUPPLYING LOWS IN
THE TEENS NORTHWEST...WITH 20S COMMON OVER MUCH OF THE REMAINDER OF
THE AREA.
&&
.LONG TERM...
SHARPLY COOLER TEMPERATURES ARE EXPECTED ON MONDAY AS COOL AIR
FLOWS SOUTH ON THE BACK SIDE OF THE DEPARTING TROUGH. ERN ZONES
MAY SEE A INCREASE IN NORTHERLY WINDS AFTER SUNRISE AS STRONGER
WINDS ON THE TAIL END OF THE CYCLONIC CIRCULATION MIX DOWN BUT
WINDS IN GENERAL WILL TREND DOWNWARD THROUGH THE DAY...BECOMING
LIGHT BY EVENING. MOSTLY CLEAR SKIES WILL COUNTER THE COLD AIR
ADVECTION TO A DEGREE AND HIGHS ARE EXPECTED TO REACH THE MIDDLE
40S...WITH SOME LOWER 50S IN THE SOUTH. ON MONDAY...AS WEAK
TRAILING DISTURBANCE WILL SLIDE SE OUT OF COLO INTO THE
PANHANDLES...BRIEFLY ENHANCING THE UPSLOPE FLOW...AND LIKELY
GENERATING SOME LIGHT SNOW SHOWERS ACROSS NE NM MONDAY MORNING.
IT IS NOT OUT OF THE QUESTION THAT SOME LIGHT SHOWERS COULD MAKE
AS FAR AS THE SW TX PANHANDLE AND WE HAVE MAINTAINED A VERY LOW
CHANCE /10 PERCENT/ OF NON-ACCUMULATING FLURRIES. OTHERWISE...WITH
COOL-SFC RIDGING PERSISTING AND SOME MID-LVL CLOUD COVER
ACCOMPANYING THE PASSING WAVE...WE DON/T EXPECT A GREAT DEAL OF
MODERATING OF TEMPS...ONLY A SLIGHT WARMING IN THE UPPER 40S/LOWER
50S. BY TUESDAY...SFC RIDGING WILL SHIFT EAST AND LEE TROUGHING
WILL COMMENCE AS UPPER FLOW TENDS TO BECOME MORE ZONAL. HIGHS
LIKELY TO WARM INTO THE 50S FOR TUESDAY.
THE WARMING TREND WILL PICK UP STEAM WED INTO THU AS UPPER FLOW BECOMES
BROADLY CYCLONIC DOWNSTREAM OF A TROUGH APPROACHING THE WEST
COAST. LOW-LVL MOISTURE RETURN WILL ALSO BEGIN ACROSS TX AND COULD
REACH OUR SRN ZONES BY THURSDAY EVENING.
MEDIUM-RANGE GUIDANCE BEGINS TO DIFFER ON THE EVOLUTION OF A CLOSED
LOW TAKING SHAPE OVER SRN CALIFORNIA LATE WEEK INTO NEXT WEEKEND ALONG
WITH THE DEVELOPMENT AND POSITION OF A DRYLINE DEVELOPING ACROSS
WEST TEXAS. THE FIRST OPPORTUNITY FOR PRECIP MAY ARRIVE FRIDAY
EVENING IF THE DRYLINE HOLDS NEAR THE CAPROCK. THEN NEXT WEEKEND
OR EARLY THE FOLLOWING WEEK...AS THE UPPER LOW EJECTS AND WITH THE
POSSIBILITY OF A COLD FRONT MOVING INTO THE AREA...THERE MAY BE A
PERIOD IN THERE OF SOME HIGHER PRECIP CHANCES. LOW CONFIDENCE IN
THE DETAILS KEEPS THE FORECAST DRY FOR NOW.
&&
.FIRE WEATHER...
COOL AND MOIST CONDITIONS WERE GREETING THE SOUTH PLAINS REGION
EARLY THIS MORNING. HOWEVER...VERY DRY AIR AND MILD CONDITIONS
WILL OVERSPREAD THE CAPROCK INTO THE WESTERN ROLLING PLAINS THIS
AFTERNOON...ON STRONG WESTERLY WINDS. EXPECT RH VALUES TO FALL
WELL BELOW 10 PERCENT...TO AS LOW AS 5 PERCENT OVER MUCH OF THE
CAPROCK AND INTO THE WESTERN ROLLING PLAINS AS SUSTAINED WESTERLY
WINDS INCREASE TO 25 TO 35 MPH AT 20 FT. THIS WILL RESULT IN A
PROLONGED PERIOD OF RED FLAG CONDITIONS...AND A RED FLAG WARNING
REMAINS IN EFFECT FOR ALL BUT THE SOUTHEAST TEXAS PANHANDLE FROM
18Z THROUGH 3Z. THERE IS SOME UNCERTAINTY IF THE STRONG WINDS AND
DRY AIR WILL ADVANCE INTO THE FAR EASTERN EXTENT OF THE CURRENT
RED FLAG WARNING...BUT HAVE CHOSEN TO MAINTAIN AS IS FOR NOW. A
STRONG COLD FRONT WILL THEN RACE FROM NORTH TO SOUTH ACROSS THE
SOUTH PLAINS THIS EVENING...BRINGING AN ABRUPT NORTHERLY WIND
SHIFT AND CONTINUED VERY STRONG WINDS. THIS WIND SHIFT WILL
COMPLICATE ANY ONGOING FIRE FIGHTING EFFORTS. THE NORTHERLY WINDS
WILL ONLY SLOWLY DECREASE THROUGH THE OVERNIGHT HOURS...THOUGH RH
VALUES WILL STEADILY CLIMB BEHIND THE FRONT.
THE FORECAST WEATHER PATTERN OF DRY WESTERLY MID-TROPOSPHERIC
FLOW AND BREEZY SOUTH TO SOUTHWEST WINDS AT THE SURFACE IN THE
DAYTIME HOURS MAY FAVOR SOME FIRE WX CONCERNS ACROSS WESTERN
AREAS DURING THE WED THROUGH SAT TIME-FRAME.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 59 19 42 19 41 / 0 10 0 10 10
TULIA 66 22 42 21 41 / 10 10 0 10 10
PLAINVIEW 68 23 44 22 42 / 10 10 0 0 10
LEVELLAND 69 21 46 23 47 / 0 10 0 0 10
LUBBOCK 71 24 46 24 47 / 0 10 0 0 10
DENVER CITY 72 24 48 26 50 / 0 0 0 0 10
BROWNFIELD 73 23 48 26 49 / 0 0 0 0 10
CHILDRESS 66 28 47 25 48 / 10 10 10 0 10
SPUR 79 29 49 26 47 / 10 10 0 0 0
ASPERMONT 76 31 50 28 50 / 10 10 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 10 PM CDT THIS
EVENING FOR THE FOLLOWING ZONES: TXZ021>024-027>031-033>044.
WIND ADVISORY FROM 1 PM THIS AFTERNOON TO MIDNIGHT CDT TONIGHT
FOR THE FOLLOWING ZONES: TXZ023-024-029>031-033>037-039>043.
HIGH WIND WARNING FROM 1 PM THIS AFTERNOON TO MIDNIGHT CDT
TONIGHT FOR THE FOLLOWING ZONES: TXZ021-022-027-028.
WIND ADVISORY FROM 7 PM THIS EVENING TO MIDNIGHT CDT TONIGHT FOR
THE FOLLOWING ZONES: TXZ025-026-032-038-044.
&&
$$
23/33
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
621 PM CDT SUN MAR 24 2013
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
221 PM CDT SUN MAR 24 2013
SNOW COMES TO AN END THIS EVENING WITH DRY AND BELOW NORMAL
TEMPERATURES EXPECTED FOR THE EARLY HALF OF THE WEEK.
CURRENTLY...LIGHT SNOW IS FALLING ACROSS PORTIONS OF THE REGION AS
A PAIR OF CLOSED MID LEVEL LOWS TRACK NEAR THE REGION. THE MORE
POTENT OF THESE LOWS IS MOVING INTO SOUTHERN ILLINOIS WHILE THE
OTHER LOW HAS STALLED OUT ACROSS THE DAKOTAS. A COUPLE BANDS OF
SNOW DEVELOPED ACROSS THE REGION THIS AFTERNOON WHERE THE LIFT
FROM THE TROUGH WAS STRONG ENOUGH TO SATURATE THROUGH THE COLUMN.
AS THE LIFT WEAKENS TONIGHT AND DRY MID LEVEL AIR ADVECTS IN FROM
THE NORTH...EXPECT THAT THE SNOW WILL QUICKLY COME TO AN END FROM
NORTH TO SOUTH. THE 24.16Z HRRR KEEPS THIS SNOW ACROSS PORTIONS OF
NORTHEAST IOWA AND SOUTHEAST MINNESOTA THROUGH 5Z...WHICH APPEARS
TO BE REASONABLE GIVEN RECENT TRENDS. OVERALL IMPACT OF THIS SNOW
HAS BEEN ON THE LOW SIDE WITH ROAD TEMPERATURES IN THE 40 TO 50F
RANGE THIS AFTERNOON WITH MUCH OF THE SNOW MELTING ON CONTACT
WITH THE ROADS. HOWEVER...AS THE SUN AND TEMPERATURES DROP
TONIGHT...SOME OF THE WET ROADS COULD HAVE SOME ICY PATCHES FORM
IF THEY DO NOT DRY OFF FIRST. CLOUD COVER WILL REMAIN OVERCAST
THROUGH THE NIGHT AS LOW AND HIGH LEVEL MOISTURE CONTENT REMAINS
FAIRLY HIGH.
WITH THE DRY NORTHWEST FLOW IN PLACE THROUGH MID WEEK FROM THE
SURFACE THROUGH THE UPPER PORTIONS OF THE ATMOSPHERE...THE MAIN
FORECAST CHALLENGES WILL BE WITH CLOUD COVER AND TEMPERATURES. HOW
THE TEMPERATURES PAN OUT WILL DIRECTLY TIE INTO HOW MUCH CLOUD
COVER THERE IS. BASED ON 24.12Z NAM/GFS RH FIELDS AND
SOUNDINGS...IT APPEARS THAT THE CLOUDS SHOULD LINGER THROUGH
TUESDAY BEFORE A RIDGE OF HIGH PRESSURE MOVES IN FROM THE WEST
TUESDAY NIGHT. THERE COULD BE A FEW BREAKS IN THE CLOUDS ON
TUESDAY...BUT OVERALL BELIEVE THAT THE SKIES WILL MAINLY BE CLOUDY
UNTIL THE RIDGE GETS IN. 850MB TEMPERATURES DO DROP SLIGHTLY OVER
THE NEXT COUPLE DAYS...FROM -10C TO -12C...BUT THEN START TO
REBOUND GOING INTO WEDNESDAY AS THE RIDGE AXIS APPROACHES FROM THE
WEST. BASED ON THE GRADUALLY THINNING CLOUD COVER...HAVE GONE
WITH A SIMILAR GRADUAL INCREASE IN TEMPERATURES.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
221 PM CDT SUN MAR 24 2013
THIS WARMING TREND WILL CONTINUE THROUGH THE REST OF THE WEEK AS
THE LONG WAVE UPPER LEVEL TROUGH OVER THE EASTERN HALF OF THE US
PROGRESSES EASTWARD AND UPPER LEVEL RIDGING TRIES TO DEVELOP
ACROSS THE CENTRAL US. WARMER LOW LEVEL AIR WILL ADVECT INTO THE
REGION FROM THE SOUTHWEST WITH 850MB TEMPERATURES REACHING +2C BY
SATURDAY AHEAD OF THE NEXT SYSTEM TO IMPACT THE REGION. THIS NEXT
SYSTEM THAT THE 24.12Z GFS/ECMWF BRING INTO THE REGION ON
SATURDAY/SATURDAY NIGHT IS CURRENTLY OFF THE WEST COAST OF ALASKA
AND APPEARS TO STALL OUT OVER THE PACIFIC NW AROUND MID WEEK.
THERMAL PROFILES FROM BOTH THE 24.12Z GFS/ECMWF SUGGEST THAT THE
PRECIPITATION WILL REACH THE GROUND AS RAIN DUE TO A DEEP WARM
LAYER FROM THE SURFACE UP TO 800MB. WITH FORECAST HIGH
TEMPERATURES OF AROUND 50F FRIDAY INTO SUNDAY AND A PERIOD OF RAIN
COMING THROUGH...WILL HAVE TO WATCH FOR SOME POTENTIAL FLOODING ON
AREA RIVERS SHOULD THIS FORECAST CONTINUE TO TREND THIS WAY.
&&
.AVIATION...TONIGHT AND MONDAY
620 PM CDT SUN MAR 24 2013
NORTHERLY FLOW BEHIND A NORTHWEST-SOUTHEAST ORIENTED TROUGH
BISECTING IOWA HAS BEEN BRINGING DRIER AIR INTO THE TAF SITES
DURING THE LAST FEW HOURS. THIS DRIER AIR HAS ALLOWED SNOW TO END
AND CEILINGS TO RISE. KRST IS AT MVFR AND KLSE AT VFR. THE
NORTHERLY FLOW IS PROGGED TO PERSIST THROUGH MONDAY...WITH SPEEDS
EVEN INCREASING DURING THE AFTERNOON TOWARDS 15 KT AS THE PRESSURE
GRADIENT TIGHTENS UP SOME. LOOKING UP TO THE NORTH...THERE IS SOME
MVFR TO VFR STRATUS OVER NORTHERN WISCONSIN...BUT NORTH OF THERE
IS A LARGE AREA OF CLEARING FROM NORTHWEST ONTARIO INTO UPPER
MICHIGAN. MODELS ARE IN PRETTY GOOD AGREEMENT THAT THIS CLEARING
IS GOING TO WORK ITS WAY SOUTH TOWARDS THE TAF SITES...BUT UNSURE
EXACTLY IF SKIES WILL CLEAR. IN ANY EVENT...WITH A NORTHERLY
BREEZE MIXING THE LOWER LEVELS OF THE ATMOSPHERE...NOCTURNAL
COOLING HELPING TO DISSIPATE ANY DIURNAL NATURE TO THE CLOUDS
TODAY...AND THE CLEARING EVENTUALLY APPROACHING...AN OPTIMISTIC
FORECAST SEEMS IN ORDER. RAISED KRST TO CLIMB TO VFR BY 03Z WITH
KLSE STAYING AT VFR THROUGH MONDAY. THE TIMING OF CLIMBING TO VFR
MAY NEED ADJUSTMENT WITH AMENDMENTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
221 PM CDT SUN MAR 24 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
546 PM CDT SAT MAR 23 2013
.SHORT TERM...TONIGHT THROUGH TUESDAY
321 PM CDT SAT MAR 23 2013
THE MAIN FOCUS THROUGH EARLY NEXT WEEK IS WITH THE SNOW THAT WILL
MOVE IN OVERNIGHT AND END SUNDAY NIGHT.
BROAD MID LEVEL TROUGHING IN PLACE ACROSS THE EASTERN ROCKIES AND
WESTERN PLAINS WITH A NUMBER OF TROUGHS EMBEDDED WITHIN THIS FLOW.
THE FIRST MID LEVEL SHORT WAVE TROUGH HAS PROPAGATED ACROSS IOWA
AND SOUTHERN MINNESOTA AND HAS BROUGHT AN INCREASE IN HIGH LEVEL
CLOUD COVER WITH IT. THERE IS TOO MUCH DRY LOW LEVEL AIR IN PLACE
RIGHT NOW FOR THIS FEATURE TO PRODUCE ANY PRECIPITATION...SO THE
FOCUS THEN GOES TO THE NEXT...MORE VIGOROUS CLOSED MID LEVEL LOW
THAT CURRENTLY IS IN EASTERN COLORADO AND SITS AT THE BASE OF THE
LONG WAVE TROUGH. THIS FEATURE WILL TAKE A DUE EAST TRACK ACROSS
THE MID MISSISSIPPI VALLEY REGION TONIGHT INTO TOMORROW. THIS
TROUGH WILL PROVIDE THE MAIN LIFTING MECHANISM FOR THE NEXT PERIOD
OF SNOW THAT WILL MOVE IN OVERNIGHT AND LAST THROUGH MUCH OF THE
DAY. AT THE SURFACE...BROAD RIDGING EXTENDS ACROSS CENTRAL CANADA
WITH A LOW ANALYZED OVER NEW MEXICO. IN BETWEEN THESE TWO
FEATURES...IT IS MAINLY JUST A WEST TO EAST PRESSURE GRADIENT WITH
AN INVERTED TROUGH EXTENDING NORTH OUT OF THE LOW ACROSS EASTERN
COLORADO. THE 23.12Z SUITE OF MODEL GUIDANCE ALL APPEAR TO HAVE
INITIALIZED WELL...THOUGH THE 23.12Z TO 23.18Z RAP IS WAY OFF ON
THE SNOW DEPTH WHICH CREATES WAY TOO WARM OF TEMPERATURES IN THE
AREAS WHERE THERE IT THINKS THERE IS NO SNOW PACK.
AS THE CLOSED MID LEVEL LOW TRACKS TO THE EAST TONIGHT...THE
INVERTED SURFACE TROUGH WILL BECOME A LITTLE MORE AMPLIFIED AND
BECOME THE MAIN LOW LEVEL CONVERGENCE FEATURE THAT THE SNOW WILL
BECOME FOCUSED AROUND. THE DEEPER LIFT WILL COME IN AHEAD OF THE
TROUGH WITH MUCH OF THE HIGHEST OMEGA SHOWING UP IN THE 600-500MB
RANGE. WITH THE OVERALL LIFT NOT BEING VERY DEEP...THE CONCERN IS
WITH A DRY LAYER BETWEEN 800-600MB THAT THIS LIFT WILL HAVE TO
OVERCOME...PARTICULARLY THE FARTHER NORTH AND EAST YOU GET FROM
THE CORE OF THE SYSTEM. THE 23.12Z NAM/GFS BUFKIT SOUNDINGS DO
SHOW A DECENT SIZED DENDRITIC GROWTH ZONE THAT IS ABOUT 150MB DEEP
FOR MUCH OF THE EVENT...BUT THE LIFT IS ONLY IN THAT SECTION OF
THE SOUNDING FOR A BRIEF PERIOD. ANY DENDRITES THAT FALL THROUGH
THE DRY LAYER WILL LIKELY SHRINK AS THEY MAKE IT THROUGH ON THEIR
WAY DOWN THE GROUND. OVERALL...FAIRLY CONFIDENT THAT AREAS ALONG
AND WEST OF THE MISSISSIPPI RIVER WILL SEE A LIGHT ACCUMULATING
SNOW FROM LATE TONIGHT THROUGH MUCH OF THE DAY. GENERALLY HAVE
ABOUT 1 TO 2 INCHES RUNNING ACROSS NORTHEAST IOWA AND A PORTION OF
SOUTHEAST MINNESOTA WITH LESSER AMOUNTS ALONG AND NORTHEAST OF THE
MISSISSIPPI RIVER. AS THE NORTHERLY LOW TO MID LEVEL FLOW KICKS IN
SUNDAY NIGHT...THE 800-600MB WEDGE OF DRY AIR GETS PULLED BACK
DOWN TO THE SOUTH AND SHOULD BRING AN END TO THE SNOW FAIRLY
QUICKLY IN THE EVENING.
BEYOND THIS...WE STAY IN LOW LEVEL CYCLONIC FLOW WITH WEAK RIDGING
ALOFT IN THE WAKE OF THE TROUGH. MAY STILL SEE SOME FLURRIES ON
MONDAY DUE TO SOME WEAK LOW LEVEL LIFT DUE TO THE CYCLONIC FLOW
WITH THE SATURATED PORTION OF THE LOW LEVEL PROFILE BEING COLD
ENOUGH WHERE ICE WILL BE PRESENT. OTHERWISE THE CHALLENGES WILL BE
WITH TEMPERATURES AND CLOUD COVER WITH SOME CLEARING POSSIBLE
GOING INTO TUESDAY.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
321 PM CDT SAT MAR 23 2013
THE GOOD NEWS IN THE LONG TERM PERIOD IS THAT IT APPEARS THE MID LEVEL
TROUGH STARTS TO BREAK DOWN AND PUSH TO THE EAST WITH GRADUAL MID
LEVEL RIDGING DEVELOPING ACROSS THE WESTERN HALF OF THE US. WHILE
THE UPPER MISSISSIPPI RIVER VALLEY IS STILL IN GENERAL NORTHWEST
FLOW ALOFT...THE LOW LEVEL FLOW BECOMES MORE SOUTHWESTERLY WITH
850MB TEMPERATURES SLOWLY INCREASING FROM -10C TUESDAY NIGHT TO
AROUND 0C BY FRIDAY. PRECIPITATION WISE...THERE IS SOME SUGGESTION
THAT THE VORT MAX CURRENTLY OVER THE WESTERN PART OF HUDSON BAY
EVENTUALLY GETS CAUGHT IN THE NORTHWEST FLOW ALOFT AND PULLS IT
DOWN INTO THE UPPER GREAT LAKES BY FRIDAY NIGHT. WITH MUCH OF THE
FORCING FROM THIS SYSTEM LIKELY STAYING TO THE NORTHEAST...HAVE
KEPT THE FORECAST DRY FROM MID WEEK INTO SATURDAY.
&&
.AVIATION...TONIGHT AND SUNDAY
546 PM CDT SAT MAR 23 2013
A TROUGH OF LOW PRESSURE HAS DEVELOPED FROM KLSE SOUTHWEST INTO
OKLAHOMA THIS AFTERNOON. PRESENTLY PLENTY OF DRY AIR EXISTS AROUND
THE TROUGH OVER THE TAF SITES...WHICH WILL HELP MAINTAIN VFR
CONDITIONS TONIGHT. AS 12Z APPROACHES...A WAVE OF LOW PRESSURE
WILL RIDE UP THE TROUGH AND REACH KRST...THEN STALL IN PLACE
THROUGH THE DAY SUNDAY. THIS WAVE IS EXPECTED TO PRODUCE LIGHT
SNOW AT KRST BEGINNING AROUND 12Z AND LASTING AGAIN THROUGH THE
DAY. VISIBILITIES ARE A LITTLE TOUGH TO FORECAST AS THE FORCING IS
NOT AT ALL STRONG WITH THIS WAVE. FIGURE THE FORCING SHOULD BE
STRONG ENOUGH TO DROP VISIBILITIES QUICKLY TO IFR. IT IS A
DIFFERENT STORY AT KLSE AS EAST TO NORTHEAST FLOW FROM THE LOWER
TO MIDDLE LEVELS OF THE TROPOSPHERE WILL TEND TO SLOW UP THE
ARRIVAL OF THE SNOW...AS WELL AS THE INTENSITY. THEREFORE...HAVE
KEPT THE MVFR VISIBILITIES FORECAST...WITH EVEN AN IMPROVING TREND
TO VFR LATE IN THE DAY AS THE LOW PRESSURE TROUGH BEGINS TO SHIFT
SOUTHWEST. CEILINGS ARE TRICKY AS WELL...GIVEN THE DRY LOW LEVEL
FLOW. HAVE PLAYED MAINLY MVFR AT KRST AND VFR AT KLSE THINKING THE
DRY AIR WILL PREVENT LOWER CEILINGS FROM DEVELOPING. IF THE
FORCING FOR SNOW IS MORE THAN EXPECTED...THEN IFR CEILINGS WOULD
OCCUR...PARTICULARLY AT KRST.
TOTAL SNOWFALL AMOUNTS THROUGH SUNDAY WILL BE LIGHT...MAINLY AN
INCH OR LESS...AND PERHAPS ONLY A TRACE AT KLSE. WITH MOST OF THE
SNOW FALLING DURING THE DAY...A LOT OF IT IS LIKELY TO MELT TOO
WITH THE HIGH SUN ANGLE NOW.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
321 PM CDT SAT MAR 23 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
321 PM CDT SAT MAR 23 2013
.SHORT TERM...TONIGHT THROUGH TUESDAY
321 PM CDT SAT MAR 23 2013
THE MAIN FOCUS THROUGH EARLY NEXT WEEK IS WITH THE SNOW THAT WILL
MOVE IN OVERNIGHT AND END SUNDAY NIGHT.
BROAD MID LEVEL TROUGHING IN PLACE ACROSS THE EASTERN ROCKIES AND
WESTERN PLAINS WITH A NUMBER OF TROUGHS EMBEDDED WITHIN THIS FLOW.
THE FIRST MID LEVEL SHORT WAVE TROUGH HAS PROPAGATED ACROSS IOWA
AND SOUTHERN MINNESOTA AND HAS BROUGHT AN INCREASE IN HIGH LEVEL
CLOUD COVER WITH IT. THERE IS TOO MUCH DRY LOW LEVEL AIR IN PLACE
RIGHT NOW FOR THIS FEATURE TO PRODUCE ANY PRECIPITATION...SO THE
FOCUS THEN GOES TO THE NEXT...MORE VIGOROUS CLOSED MID LEVEL LOW
THAT CURRENTLY IS IN EASTERN COLORADO AND SITS AT THE BASE OF THE
LONG WAVE TROUGH. THIS FEATURE WILL TAKE A DUE EAST TRACK ACROSS
THE MID MISSISSIPPI VALLEY REGION TONIGHT INTO TOMORROW. THIS
TROUGH WILL PROVIDE THE MAIN LIFTING MECHANISM FOR THE NEXT PERIOD
OF SNOW THAT WILL MOVE IN OVERNIGHT AND LAST THROUGH MUCH OF THE
DAY. AT THE SURFACE...BROAD RIDGING EXTENDS ACROSS CENTRAL CANADA
WITH A LOW ANALYZED OVER NEW MEXICO. IN BETWEEN THESE TWO
FEATURES...IT IS MAINLY JUST A WEST TO EAST PRESSURE GRADIENT WITH
AN INVERTED TROUGH EXTENDING NORTH OUT OF THE LOW ACROSS EASTERN
COLORADO. THE 23.12Z SUITE OF MODEL GUIDANCE ALL APPEAR TO HAVE
INITIALIZED WELL...THOUGH THE 23.12Z TO 23.18Z RAP IS WAY OFF ON
THE SNOW DEPTH WHICH CREATES WAY TOO WARM OF TEMPERATURES IN THE
AREAS WHERE THERE IT THINKS THERE IS NO SNOW PACK.
AS THE CLOSED MID LEVEL LOW TRACKS TO THE EAST TONIGHT...THE
INVERTED SURFACE TROUGH WILL BECOME A LITTLE MORE AMPLIFIED AND
BECOME THE MAIN LOW LEVEL CONVERGENCE FEATURE THAT THE SNOW WILL
BECOME FOCUSED AROUND. THE DEEPER LIFT WILL COME IN AHEAD OF THE
TROUGH WITH MUCH OF THE HIGHEST OMEGA SHOWING UP IN THE 600-500MB
RANGE. WITH THE OVERALL LIFT NOT BEING VERY DEEP...THE CONCERN IS
WITH A DRY LAYER BETWEEN 800-600MB THAT THIS LIFT WILL HAVE TO
OVERCOME...PARTICULARLY THE FARTHER NORTH AND EAST YOU GET FROM
THE CORE OF THE SYSTEM. THE 23.12Z NAM/GFS BUFKIT SOUNDINGS DO
SHOW A DECENT SIZED DENDRITIC GROWTH ZONE THAT IS ABOUT 150MB DEEP
FOR MUCH OF THE EVENT...BUT THE LIFT IS ONLY IN THAT SECTION OF
THE SOUNDING FOR A BRIEF PERIOD. ANY DENDRITES THAT FALL THROUGH
THE DRY LAYER WILL LIKELY SHRINK AS THEY MAKE IT THROUGH ON THEIR
WAY DOWN THE GROUND. OVERALL...FAIRLY CONFIDENT THAT AREAS ALONG
AND WEST OF THE MISSISSIPPI RIVER WILL SEE A LIGHT ACCUMULATING
SNOW FROM LATE TONIGHT THROUGH MUCH OF THE DAY. GENERALLY HAVE
ABOUT 1 TO 2 INCHES RUNNING ACROSS NORTHEAST IOWA AND A PORTION OF
SOUTHEAST MINNESOTA WITH LESSER AMOUNTS ALONG AND NORTHEAST OF THE
MISSISSIPPI RIVER. AS THE NORTHERLY LOW TO MID LEVEL FLOW KICKS IN
SUNDAY NIGHT...THE 800-600MB WEDGE OF DRY AIR GETS PULLED BACK
DOWN TO THE SOUTH AND SHOULD BRING AN END TO THE SNOW FAIRLY
QUICKLY IN THE EVENING.
BEYOND THIS...WE STAY IN LOW LEVEL CYCLONIC FLOW WITH WEAK RIDGING
ALOFT IN THE WAKE OF THE TROUGH. MAY STILL SEE SOME FLURRIES ON
MONDAY DUE TO SOME WEAK LOW LEVEL LIFT DUE TO THE CYCLONIC FLOW
WITH THE SATURATED PORTION OF THE LOW LEVEL PROFILE BEING COLD
ENOUGH WHERE ICE WILL BE PRESENT. OTHERWISE THE CHALLENGES WILL BE
WITH TEMPERATURES AND CLOUD COVER WITH SOME CLEARING POSSIBLE
GOING INTO TUESDAY.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
321 PM CDT SAT MAR 23 2013
THE GOOD NEWS IN THE LONG TERM PERIOD IS THAT IT APPEARS THE MID LEVEL
TROUGH STARTS TO BREAK DOWN AND PUSH TO THE EAST WITH GRADUAL MID
LEVEL RIDGING DEVELOPING ACROSS THE WESTERN HALF OF THE US. WHILE
THE UPPER MISSISSIPPI RIVER VALLEY IS STILL IN GENERAL NORTHWEST
FLOW ALOFT...THE LOW LEVEL FLOW BECOMES MORE SOUTHWESTERLY WITH
850MB TEMPERATURES SLOWLY INCREASING FROM -10C TUESDAY NIGHT TO
AROUND 0C BY FRIDAY. PRECIPITATION WISE...THERE IS SOME SUGGESTION
THAT THE VORT MAX CURRENTLY OVER THE WESTERN PART OF HUDSON BAY
EVENTUALLY GETS CAUGHT IN THE NORTHWEST FLOW ALOFT AND PULLS IT
DOWN INTO THE UPPER GREAT LAKES BY FRIDAY NIGHT. WITH MUCH OF THE
FORCING FROM THIS SYSTEM LIKELY STAYING TO THE NORTHEAST...HAVE
KEPT THE FORECAST DRY FROM MID WEEK INTO SATURDAY.
&&
.AVIATION...THROUGH 18Z SUNDAY
1230 PM CDT SAT MAR 23 2013
INCREASING MID/HIGH LEVEL CLOUDS THIS AFTERNOON ACROSS THE REGION
WILL GIVE WAY TO LIGHT SNOW BY SUNRISE SUNDAY AS A DEEPENING LOW
PRESSURE TRACKS ACROSS THE MID MISSISSIPPI RIVER VALLEY.
UPPER LEVEL FORCING ASSOCIATED WITH THE STORM SYSTEM WILL COMPETE
WITH STRONG LOW LEVEL NORTHEASTERLY FEED OF DRIER AIR. WEST OF THE
MISSISSIPPI RIVER...THE ATMOSPHERE IS EXPECTED TO BECOME
SUFFICIENTLY SATURATED BY 10Z TO START LIGHT SNOW AT
KRST...MEANWHILE IT WILL TAKE A FEW MORE HOURS AT KLSE.
VISIBILITIES LOOK TO DROP TO IFR AT KRST BY MID MORNING...BUT
SHOULD REMAIN MVFR AT KLSE THROUGH THE PERIOD. CEILINGS WILL
STRUGGLE TO LOWER MORE THAN MVFR WITH THE AFOREMENTIONED DRIER AIR
BUT AT THIS TIME WILL CONTINUE TO SHOW THICKENING AND LOWERING AT
BOTH TAF SITES...ESPECIALLY AFTER 12Z SUNDAY. IFR/MVFR CONDITIONS
WILL PERSIST INTO THE EARLY EVENING AT BOTH SITES. TOTAL SNOWFALL
AMOUNTS ARE EXPECTED TO VARY FROM LESS THAN 1 INCH AT KLSE...TO
POSSIBLY 1.5 INCHES AT KRST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
321 PM CDT SAT MAR 23 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...ZT
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1207 AM MDT MON MAR 25 2013
.UPDATE...SNOW IS A LITTLE MORE PERSISTENT AND RADAR/SATELLITE
SHOW SOME UPSTREAM MOISTURE AND CLOUDINESS. SHORT RANGE MODELS ARE
NOT MUCH HELP AT THIS POINT...BUT BASED ON SATELLITE/RADAR/OBS
CANT RULE OUT LIGHT SHOWERS OR AT LEAST A FEW FLURRIES LINGERING
INTO THE EARLY MORNING HOURS.
&&
.AVIATION...DELAYED IMPROVEMENT IN TAFS AT KAPA BASED ON CURRENT
RADAR. STILL CANT RULE OUT A FLURRY OR TWO AT KDEN AND KBJC WITH
LOWER CEILINGS OF 600 FEET TO 1500 FEET AT KBJC 09Z-11Z.
&&
.PREV DISCUSSION... /ISSUED 742 PM MDT SUN MAR 24 2013/
UPDATE...THERE IS A BAND OF SNOW SINKING SOUTH ACROSS SOUTHERN
WELD...ADAMS AND ARAPAHOE COUNTIES. ADJUSTED FORECAST TO MATCH UP
WITH THIS AS IT SHIFTS SOUTH. OUTSIDE OF THIS AREA LOWERED POPS.
SATELLITE INDICATES SHOWERS ARE DECREASING. STILL EXPECT MOST OF
THE ACTIVITY TO END BY MIDNIGHT. A FEW LIGHT SNOW SHOWERS WILL
REMAIN POSSIBLE OVER THE MOUNTAINS AFTER MIDNIGHT AND WILL KEEP
LOW POPS IN FOR THIS. ANY SNOW THAT FALL WILL BE LIGHT...MAINLY
LESS THAN AN INCH. IT WILL BE ANOTHER COLD NIGHT WITH SINGLE
DIGITS EXPECTED ACROSS NORTHEAST COLORADO.
AVIATION...SNOW SHOWERS WILL REMAIN POSSIBLE THROUGH 06Z.
VISIBILITY WILL FALL TO AROUND ONE MILE WITH CEILINGS AS LOW AS
1500 FEET IN THE SNOW SHOWERS. OUTSIDE OF THE SNOW...CEILINGS
WILL BE 4000 TO 8000 FEET THROUGH 06Z...AND THEN RISE. IF ENOUGH
CLEARING TAKES PLACE LATE TONIGHT...CAN`T RULE OUT PATCHY FOG.
WINDS WILL TURN NORTHEASTERLY IN THE NEXT COUPLE OF HOURS. THEY
WILL BE LIGHT AFTER 06Z AND END UP SOUTHERLY.
PREV DISCUSSION... /ISSUED 237 PM MDT SUN MAR 24 2013/
.CORRECTED SPELLING ERRORS...
SHORT TERM...A DISTURBANCE IN NW FLOW ALOFT WILL MOVE ACROSS THE
AREA THIS EVENING AS A BNDRY BRIEFLY ENHANCES UPSLOPE FLOW ALONG
THE FRONT RANGE. LAPSE RATES IN AND NR THE FOOTHILLS WILL BE
AROUND 8 C/KM. THUS WOULD EXPECT SNOW SHOWER ACTIVITY THRU THE
EARLY EVENING HOURS. BOTH THE RAP AND HRRR ARE SHOWING AMOUNTS IN
THE FOOTHILLS WEST AND SOUTHWEST OF DENVER UP TO 4 INCHES WITH UP
TO 2 INCHES IN THE WRN SUBURBS. FURTHER EAST AMOUNTS ARE IN AN
INCH OR LESS. ANOTHER AREA OF SNOW MAY RESIDE NR THE WY-CO BORDER
IN NR WELD COUNTY WHERE AN INCH OR TWO MAY FALL. IN THE MTNS WILL
CONTINUE TO SEE SOME OROGRAPHIC -SHSN WITH A FEW INCHES POSSIBLE
AS WELL. BY MIDNIGHT MOST ACTIVITY SHOULD END ALTHOUGH RAP SHOWS
SHOW LIGHT ACTIVITY NR THE WY BORDER.
ON MON DRIER AIR WILL BE OVER THE AREA IN NW FLOW ALOFT HOWEVER
SOME LINGERING MOISTURE IN THE MTNS MAY ALLOW FOR A SLIGHT CHC OF
-SHSN. AS FOR TEMPS WITH SFC HIGH PRES STILL OVER THE AREA AND
LINGERING SNOWPACK WILL KEEP HIGHS MAINLY IN THE UPPER 20S TO
LOWER 30S ACROSS NERN CO.
LONG TERM...NORTHWESTERLY FLOW ALOFT IS TO DOMINATE THE FORECAST
AREA MONDAY NIGHT THROUGH TUESDAY...THEN UPPER RIDGING GETS OVER
THE STATE AND THE FLOW ALOFT IS ZONAL. THE SYNOPTIC SCALE ENERGY
PROGGED OVER THE CWA IS BENIGN ACCORDING TO THE Q-G VERTICAL
VELOCITY FIELDS MONDAY NIGHT THROUGH WEDNESDAY NIGHT. THE LOW
LEVEL WIND AND PRESSURE FIELDS SHOW NORMAL DIURNAL TRENDS
CONCERNING THE BOUNDARY LAYER WINDS MONDAY NIGHT THROUGH WEDNESDAY
NIGHT. MODELS HAVE LIMITED MOISTURE AROUND MONDAY NIGHT. ON
TUESDAY...MOISTURE INCREASES OVER THE MOUNTAINS AND IN THE MID AND
UPPER LEVELS OF THE PLAINS...ESPECIALLY ON THE GFS. THIS CONTINUE
INTO WEDNESDAY...BEFORE DRYING OUT SOMEWHAT WEDNESDAY NIGHT. THE QPF
FIELDS HAVE MINIMAL MEASURABLE PRECIPITATION NOTED...MOSTLY OVER THE
MOUNTAINS...TUESDAY AFTERNOON...THEN AGAIN WEDNESDAY INTO WEDNESDAY
EVENING. WILL GO WITH 20-40% POPS IN THE MOUNTAINS TUESDAY AFTERNOON
THROUGH WEDNESDAY EVENING. FOR TEMPERATURES... TUESDAY`S HIGHS ARE
ABOUT 6 C WARMER THAN MONDAY`S HIGHS. WEDENSDAY`S HIGHS ARE 1-3 C
WARMER THAN TUESDAY`S. FOR THE LATER DAYS...THURSDAY THROUGH
SUNDAY...NOW THE MODELS KEEP UPPER RIDGING OVER COLORADO ALL FOUR
DAYS. THE UPPER CLOSED LOW STAYS WELL WEST OF THE THE STATE THROUGH
SUNDAY ON THESE LATEST RUNS.
AVIATION...WILL STILL SEE A CHC OF SNOW SHOWERS THU 02Z WITH
ACCUMULATIONS AT DIA AN INCH OR LESS. AFTER 02Z SNOW CHANCES
SHOULD DIMINISH WITH ONLY A FEW FLURRIES POSSIBLE. CEILINGS AND
VISIBILITIES MAY STILL DROP DOWN TO MVFR LVLS DUE TO SNOW THRU
02Z. AFTER 02Z WILL KEEP CEILINGS AROUND 6000 FT THRU 07Z. WINDS
SHOULD BE NNE THRU THE EARLY EVENING BUT THEN BECOME LIGHT SSWLY
AFTER 03Z THRU MON MORNING. ON MON EXPECT VFR CONDITIONS WITH
LIGHT SSE WINDS BY AFTN.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....99
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
447 AM EDT MON MAR 25 2013
.SYNOPSIS...
COMPLEX LOW PRESSURE APPROACHING FROM THE SOUTHWEST WILL CONSOLIDATE
AS A LOW PRESSURE CENTER OFF THE NORTHERN MID ATLANTIC COAST TODAY
AND THEN DEEPEN AND MOVE AWAY FROM THE COAST. HIGH PRESSURE TO OUR
WEST WILL STRUGGLE TO BUILD IN THROUGH THE REMAINDER OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EVEN THOUGH PRECIPITATION IS STEADILY MOVING INTO OUR REGION FROM
THE SOUTHWEST THIS MORNING, THIS IS STILL A LOW CONFIDENCE FORECAST,
MAINLY DUE TO BOUNDARY LAYER TEMPERATURES. REGIONAL RADAR IS SHOWING
A LOT OF MOISTURE SURGING ACROSS THE BMORE/DC CORRIDOR WITH A
MAJORITY OF THE SURFACE OBSERVATIONS AT OR BELOW 35F WITH FALLING
SNOW...SOME SITES ARE SHOWING MODERATE TO HEAVY SNOW WITHIN THE
CURRENT BANDING STRUCTURES.
THE OVERALL DYNAMICS OF THIS SYSTEM ARE AMAZING IN TERMS OF
PRECIPITATION GENERATION BUT AS HAS BEEN HARPED ON BY SEVERAL SHIFTS
NOW, DO WE COOL ENOUGH TODAY TO ALLOW FOR AN ACCUMULATING
SNOWFALL...AGAIN WE ARE FIGHTING THE HIGHER MARCH SUN ANGLE AS WELL.
ACROSS OUR NECK OF THE WOODS WE STILL HAVE A PRIMARILY
EAST-NORTHEAST FLOW FEEDING IN OFF THE WARMER ATLANTIC WATERS.
GRANTED WE DO HAVE AMPLE DRY AIR AT THE SURFACE IN WHICH TO
EVAPORATIVELY COOL OUR COLUMN TO ALLOW FOR ALL SNOW, BUT WE NEED THE
BANDING FEATURES TO PROVIDE THE EXTRA BOAST TO ALLOW THE SNOW TO
STICK.
OCEAN TEMPERATURES ARE IN THE LOW-40S AND AS WAS SAID ABOVE
OUR BOUNDARY LAYER WINDS ARE DIRECTLY OFF THE WATERS. THIS SYSTEM IS
NOT BRINGING ANY COLD AIR WITH IT AND ITS NOT WRAPPING COLD AIR DOWN
FROM CANADIAN EITHER SO IT HAS TO PRODUCE VERY STRONG VERTICAL
VELOCITIES IN ORDER TO DYNAMICALLY COOL THE COLUMN. THE RAP HAS BEEN
FAIRLY CONSISTENT IN BRINGING IN THE FIRST FLAKES/DROPS ACROSS THE
PHILADELPHIA METRO AREA BY 10-11Z...ALTHOUGH IT IS LIGHT
PRECIPITATION. FROM THERE THE PRIMARY SURFACE LOW OVER THE OHIO
VALLEY BEGINS TO FEED THE DEVELOPING VIRGINIA COASTAL LOW MORE
ENERGY. THE COASTAL LOW DEEPENS AND SLINGS MORE MOISTURE BACK ACROSS
OUR REGION IN THE FORM OF A TROWAL. THIS FEATURE WILL BE THE MAIN
PLAYER FOR SNOWFALL LATER THIS MORNING. IF IT MOVES TOO FAR EAST WE
LOSE THE HIGHER QPF AND BANDING FEATURES.
DID NOT CHANGE MUCH IN TERMS OF THE SNOWFALL THIS MORNING AS THE
EVENT HAS YET TO REALLY TAKE SHAPE. WE KEEP THE CURRENT ADVISORIES
AND WARNINGS IN PLACE AS IS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
THE ENTIRE EVENT SHOULD BE WINDING DOWN BY LATER THIS EVENING
ALTHOUGH SOME OF THE MODELS ARE SHOWING SOME LINGERING SHOWERS
WRAPPING AROUND AND IMPACTING OUR EASTERN ZONES. BY THIS POINT AND
TIME THOUGH OUR WINDS WILL HAVE BACKED TOWARDS THE NORTHWEST AND
TEMPERATURES WILL NO LONGER BE IN QUESTION, TO ALLOW FOR SNOW
SHOWERS. A COATING TO A HALF INCH IS POSSIBLE WITH THESE SHOWERS. WE
SHOULD BE COMPLETELY DRYING OUT LATE TONIGHT AS DRIER AIR IS PUMPED
IN FROM THE NORTHWEST. TEMPERATURES WILL BE IN THE LOW-30S TONIGHT.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
A MAJOR TROUGH AXIS EMANATING FROM THE NEAR AND SHORT TERMS` MID
LEVEL LOW LOOKS TO EXTEND INTO NEW ENGLAND AND THE NORTHERN MID
ATLANTIC REGION THROUGH MUCH OF THE WORK WEEK. IT SHOULD KEEP
SURFACE HIGH PRESSURE FROM THE WEST AT BAY. IT ALSO SHOULD KEEP THE
AREA UNDER A FAIR AMOUNT OF STRATOCUMULUS AND SPOTTY AND
INTERMITTENT SNOW OR RAIN SHOWER ACTIVITY ESPECIALLY NORTHWEST. WE
SHOULD REMAIN COLDER THAN NORMAL FOR LATE MARCH. AT THIS POINT, WE
DON`T SEE ANYTHING HAZARDOUS IN ALL THIS EXCEPT THAT AN ABSENCE OF
SIGNIFICANT PRECIPITATION AND A NORTHWEST SURFACE FLOW THAT WILL BE
BRISK AT TIMES MIGHT LEAD TO FIRE WEATHER CONCERNS.
THE MODELS DO AGREE ON BRINGING A WEAK MID LEVEL RIDGE AXIS AND
ASSOCIATED SURFACE HIGH PRESSURE INTO OUR AREA BY SUNDAY, AND
THAT WOULD BRING MORE SEASONABLE TEMPERATURES AND GENTLE WINDS.
HOWEVER, THEY ALSO AGREE THAT ANOTHER MID LEVEL VORTEX PUSHES DOWN
TOWARD THE AREA WITH AN ATTENDANT SURFACE COLD FRONT CLOSING IN BY
THE END OF THE PERIOD.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VERY TRICKY FORECAST ON TAP FOR OUR TERMINALS TODAY. COMPLEX LOW
PRESSURE SYSTEM WILL CONTINUE TO FORM AND CONSOLIDATE OFF THE
VIRGINIA COASTLINE TODAY. MOISTURE WILL SURGE UP FROM THE
SOUTH-SOUTHWEST LATER THIS MORNING PRODUCING A WIDESPREAD SNOWFALL.
THIS WILL LIMIT VSBYS AND CIGS TO THE MVFR RANGE. A BAND OR TWO OF
HEAVIER SNOW/RAIN COULD FORM AND MOVE NORTHWARD ACROSS THE REGION AS
THE SURFACE LOW PRESSURE MOVES CLOSER. THIS WOULD ALLOW AN EVEN
FURTHER DETERIORATION IN CONDITIONS WITH LIFR POSSIBLE UNDER THESE
BANDS. CONTINUED THE TEMPO GROUP FOR SUCH CONDITIONS AS EXACT TIMING
IS HARD TO PIN POINT, BUT INDICATIONS SHOW BY EARLY AFTERNOON.
THE LOW WILL SLIDE TO OUR NORTHEAST LATER TODAY WITH SURFACE WINDS
BACKING TOWARDS THE NORTH-NORTHWEST. THIS SHOULD HELP TO DRY THINGS
OUT A BIT AND LIFT VSBYS AND CIGS BACK INTO THE MVFR RANGE WITH SOME
SCATTERED SHOWERS AROUND. BY THIS EVENING WE ARE FORECASTING VFR
CONDITIONS TO PREVAIL AT MOST OF OUR TERMINALS, EXCLUDING MIV AND
ACY DUE TO THEIR CLOSER PROXIMITY TO THE SURFACE LOW.
OUTLOOK...
TUESDAY...MAINLY VFR CONDITIONS. CONFIDENCE IS MODERATE.
WEDNESDAY...MAINLY VFR CONDITIONS BUT NORTHWEST WINDS POSSIBLY
GUSTING TO 20 TO 25 KT. CONFIDENCE IS MODERATE.
THURSDAY...MAINLY VFR CONDITIONS. CONFIDENCE IS MODERATE.
FRIDAY...MAINLY VFR CONDITIONS. CONFIDENCE IS MODERATE.
&&
.MARINE...
WE CONTINUE THE SCA AND GALES FOR OUR WATERS TODAY AND TONIGHT...NO
CHANGES. WINDS WILL GENERALLY BE OUT OF THE EAST-NORTHEAST AND
INCREASE TODAY AS LOW PRESSURE OFFSHORE DEEPENS. MORE RAIN AND SNOW
ARE EXPECTED TO SHIFT OVER OUR WATERS THIS MORNING AND
AFTERNOON...HEAVY AT TIMES. THE LOW WILL QUICKLY PULL AWAY LATER
TONIGHT AND WINDS WILL SHIFT TOWARDS THE NORTHWEST. THE PRESSURE
GRADIENT WILL ALSO WEAKEN ALLOWING THE WINDS AND SEAS TO RELAX A BIT.
OUTLOOK...
ADVISORY CONDITIONS ARE EXPECTED ON TUESDAY. WINDS ARE EXPECTED TO
DROP BELOW THE ADVISORY CRITERION DURING THE DAY, BUT SEAS WILL BE
SLOWER TO SUBSIDE. WINDS ARE EXPECTED TO PICK UP AGAIN TO ADVISORY
LEVELS ON WEDNESDAY. WINDS AND SEAS WILL SUBSIDE ON THURSDAY AND
CONTINUE INTO FRIDAY.
&&
.TIDES/COASTAL FLOODING...
A COASTAL FLOOD ADVISORY REMAINS IN EFFECT FOR THIS EVENING`S HIGH
TIDE. THE AREA OF CONCERN REMAINS THE SHORE AREAS OF NEW JERSEY AND
DELAWARE, ADJACENT BACK BAYS INCLUDING BARNEGAT BAY, AND ALSO
RARITAN BAY, LOWER DELAWARE BAY AND THEIR TIDAL TRIBUTARIES.
THE OFS AND EXTRATROPICAL GUIDANCE SUGGEST LOW END MINOR TIDAL
FLOODING FOR THE HIGH TIDE THAT OCCURS THIS EVENING. LOCAL GUIDANCE
SUGGESTS MORE SOLID MINOR TIDAL FLOODING. THE EXPECTED GALE FORCE
WINDS AND SEAS WOULD SEEM TO ARGUE FOR THE LATTER. TIDAL DEPARTURES
EARLY THIS MORNING HAD ALREADY EXCEEDED A FOOT AS WINDS WERE FROM
THE EAST NORTHEAST AND JUST MOVING INTO THE SMALL CRAFT ADVISORY
RANGE. MINOR TIDAL FLOODING THIS EVENING REQUIRES DEPARTURES OF
AROUND TWO FEET.
WE CONTINUE TO THINK ANOTHER ROUND OF MINOR TIDAL FLOODING IS
POSSIBLE TUESDAY MORNING. IT LIKELY WOULD BE CONFINED TO THE SAME
AREA. IF ANOTHER DOMINO WERE TO FALL, IT WOULD BE UPPER DELAWARE
BAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR PAZ105-
106.
WINTER WEATHER ADVISORY UNTIL 6 PM EDT THIS EVENING FOR PAZ060-
070-071-101>104.
NJ...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR
NJZ008>010-012>015-023>026.
COASTAL FLOOD ADVISORY FROM 6 PM TO 10 PM EDT THIS EVENING FOR
NJZ012>014-020-022>027.
WINTER STORM WARNING UNTIL MIDNIGHT EDT TONIGHT FOR NJZ016>022-
027.
DE...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR DEZ003.
COASTAL FLOOD ADVISORY FROM 6 PM TO 10 PM EDT THIS EVENING FOR
DEZ003-004.
WINTER WEATHER ADVISORY UNTIL 6 PM EDT THIS EVENING FOR DEZ001-
002.
MD...WINTER WEATHER ADVISORY UNTIL 6 PM EDT THIS EVENING FOR MDZ008-
012-015-019-020.
MARINE...GALE WARNING UNTIL 2 AM EDT TUESDAY FOR ANZ431-452>455.
GALE WARNING FROM 11 AM THIS MORNING TO 2 AM EDT TUESDAY FOR
ANZ450-451.
SMALL CRAFT ADVISORY FROM 8 AM THIS MORNING TO 2 AM EDT
TUESDAY FOR ANZ430.
&&
$$
SYNOPSIS...DELISI
NEAR TERM...HEAVENER
SHORT TERM...HEAVENER
LONG TERM...DELISI
AVIATION...HEAVENER/DELISI
MARINE...HEAVENER/DELISI
TIDES/COASTAL FLOODING...DELISI
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
144 AM EDT MON MAR 25 2013
.AVIATION...
PINWHEELING BAND OF MIDLEVEL DEFORMATION/FGEN WILL CONTINUE TO
BRING MODERATE SNOW TO KFWA FOR THE NEXT SEVERAL HOURS. BAND OF
HEAVIEST SNOW LOOKS TO HAVE SHIFTED JUST NORTH OF THE TERMINAL PER
LATEST RADAR IMAGERY BUT IFR CIGS AND VSBYS LIKELY TO PERSIST
THROUGH THE REST OF THE OVERNIGHT WITH ANOTHER INCH OR TWO OF
ACCUMULATION POSSIBLE. SNOW WILL BEGIN TO TAPER OFF AROUND 12Z AS
THE SURFACE LOW OVER OHIO BEGINS TO WEAKEN AND UPPER LEVEL FORCING
TRANSFERS TO THE EAST COAST BUT LIGHT SNOW IN RESIDUAL
TROWAL/DEFORMATION AXIS WILL LIKELY PERSIST FOR MUCH OF THE DAY.
AVIATION CONDITIONS WILL GRADUALLY IMPROVE INTO MVFR CATEGORY
THOUGH. AT KSBN...DRY AIR WILL CONTINUE TO PREVENT ANY SIGNIFICANT
SNOW BUT CEILINGS LOOK TO HOVER AROUND HIGH END MVFR FOR MUCH OF
THE DAY. STRONG NORTHEASTERLY WINDS WILL GRADUALLY BACK TO THE
NORTH AS LOW PRESSURE EXITS THE REGION.
&&
.PREV DISCUSSION... /ISSUED 125 AM EDT SUN MAR 24 2013/
UPDATE...
SLIGHT ADJUDICATION WRT WSW VERBIAGE JUST PRIOR TO 1 AM EDT...AS
EVENT CRESCENDO UPON US AT 05 UTC...WITH FRESHENED WORDING TO RIDE
WELL INTO MORNING DRIVE. SNOWFALL RATES AT 2-2.4 INCHES PR
HOUR...THROUGH BREVITY /20 MINS AT SINGLE POINT/ PER NWD BANDED WAVE
PROPAGATION S/B SAVING FACTOR AGAINST PRODIGIOUS LOCALIZED EXTREMA
GT 1 FOOT. GAVE SLIGHT INCRS IN NWRN OH TO 5-9 INCH RANGE WITH
LOCALLY HIR NEAR ROUTE 30. CONVECTIVE INSTABILITY REALIZED ACRS
NWRN OH/VAN WERT CO. THIS MUCH IN LINE WITH IDYLLIC WEAKNESS WITHIN
THETA-E LAPSE RATES PER YDAY NAM AND NOW WITH 25/00 WRFARW.
FURTHERMORE LTST WRF WELL DEPICTING FORKED TROWAL FM CNTL OH VERTEX
INTO NRN IN AND SECONDARY INCRSGLY DOMINANT/TUCKED TROWAL WITH MORE
SUBSTANTIVE BULK MSTR ACCESS ACRS ECNTL IN INTO WCNTL OH...ROUGHLY
KMIE-KDAY. SINGLED OUT GRANT/BLACKFORD/JAY FOR MOST PROBABLE HIR
ISOLD AMOUNTS...THOUGH MAINTAINED PRIOR/REASONABLE AREAL RANGE GIVEN
IMMINENT COASTAL HANDOFF AND WRN FLANK OF SOLID SNOW WITH TRANSITION
TO A MORE INTERMITTENT CHARACTER IS NOW WELL INTO NWRN IN. PVU FOLD
SPUR NOW ROUNDED INTO VA SUGGESTS DEMARCATION PT FOR RAPID ENERGY
XFER TO FAVORABLE GULF STREAM CYCLOGENESIS HAS BEGUN...WITH RATES
MARKEDLY DIMINISHED BY SUNRISE.
PREV DISCUSSION... /ISSUED 337 PM EDT SUN MAR 24 2013/
SHORT TERM...
TONIGHT...MONDAY...MONDAY NIGHT...
LATEST WATER VAPOR IMAGERY SHOWING POTENT UPPER TROUGH AND
ASSOCIATED VORT MAX PUSHING ACROSS MISSOURI THIS AFTERNOON. LOW-MID
LEVEL ASCENT AHEAD OF THIS FEATURE IS RESULTING IN A LARGE SWATH OF
HEAVY SNOW OVER EASTERN MO AND WEST CENTRAL IL. RADAR IMAGERY
DEPICTING CONVECTIVE ELEMENTS EMBEDDED WITHIN THIS SNOW BAND WHICH
MAY ACT TO HINDER MOISTURE TRANSPORT NORTHWARD INTO OUR AREA AS THIS
SYSTEM CONTINUES TO MOVE E/NE THIS EVENING. 12Z RAOBS CONFIRMING
LATEST RAP ANALYSIS SHOWING STRONG UPPER JET TRAVERSING THROUGH THE
BASE OF THIS TROUGH...ASSOCIATED UPPER LEVEL DIVERGENCE EXPECTED TO
AID IN THE CONTINUATION OF HEAVY SNOW BAND AS IT MOVES INTO
CENTRAL/NORTHERN INDIANA TONIGHT. MODELS IN DECENT AGREEMENT IN NE
TRACK OF SFC LOW...BRINGING IT INTO NORTHERN KY BY 00Z MON AND UP
INTO SW OH BY 12Z MON...PLACING OUR SOUTHERN CWA IN FAVORABLE AREA
FOR FOR HEAVY SNOW. KEY COMPONENT IN THE EVOLUTION OF THIS SYSTEM
THAT WILL ACT TO LIMIT SNOW ACCUMULATIONS IS THE EASTWARD
PROGRESSION OF UPPER JET DYNAMICS AND THE RESULTING COASTAL TRANSFER
OF ENERGY. THIS WILL RAPIDLY DISSIPATE OH VALLEY SFC LOW MONDAY IN
FAVOR OF INTENSIFICATION OF COASTAL LOW AS CLOSED UPPER LOW
CONTINUES ON EASTWARD TRACK AND BECOMES NEARLY VERTICALLY STACKED
WITH SFC LOW OVER OH VALLEY 09-12Z MON. THAT SAID...THERE STILL
EXISTS A 12 HOUR WINDOW...00Z-12Z MON...OF FAVORABLE CONDITIONS FOR
ACCUMULATING SNOW AS ALL MODELS IN GOOD AGREEMENT WITH PRODUCING 6-8
INCHES OVER THE FAR SOUTHERN PORTION OF THE CWA AS 80-100M 500MB HT
FALLS WILL REACH UP INTO THE SOUTHERN CWA AS UPPER LOW TRACKS
THROUGH KY OVERNIGHT. AND WHILE MODELS VARY ON DEGREE OF DEEP
MOISTURE AVAILABLE...AMPLE LOW LEVEL MOISTURE ALONG WITH BETTER
ALIGNMENT OF OMEGA AND DGZ THAN PREVIOUS RUNS WILL ALSO FAVOR A GOOD
SHOT AT HVY SNOW FOR AT LEAST A BRIEF PERIOD OF TIME OVERNIGHT
ACROSS THE SOUTHERN TIER OF THE FCST AREA. WILL THEREFORE CONTINUE
WITH WARNING/ADV AREAS AND KEEP NORTHERN TIER WITHOUT HEADLINES AS
DISTINCT CUTOFF IN SNOW EXPECTED NORTH OF US6. IN THE WAKE OF THIS
SYSTEM FLOW WILL GRADUALLY BACK FROM NE TO N/NW LATE IN THE DAY
MONDAY AND BRING CHANCE FOR LES INTO OUR EXTREME NW CWA. DESPITE
UNIFORM NORTHERLY FLOW DOWN THE LONG AXIS OF LAKE MICHIGAN...LACK OF
COLD AIR WILL YIELD MARGINAL/SUB MARGINAL DELTA T AND THEREFORE
HINDER ACCUMULATIONS.
LONG TERM...
TUESDAY THROUGH SUNDAY...INCREASED SNOW CHANCES TUESDAY AND TUESDAY
NIGHT OVER AREAS DOWNSTREAM OF LAKE MICHIGAN AS VERY COLD AIR
CONTINUES TO SPREAD SOUTH OVER THE WESTERN GREAT LAKES REGION. DELTA
T VALUES RATHER MODEST AT 12C TO 14C...BUT A LONG LAKE AXIS FETCH
WITH LIKELY PRECONDITIONING FROM LAKE SUPERIOR SHOULD ALLOW FOR SOME
ORGANIZATION OF SNOW SHOWERS OVER THE LAKE. RAISED SNOWFALL AMOUNTS
TUESDAY...HOWEVER...DAYTIME HEATING SHOULD LIMIT SNOW ACCUMULATIONS.
INVERSIONS HEIGHTS SHOULD FALL LATE TUESDAY NIGHT...BRINGING AN END
TO THE SNOW SHOWERS. HIGH AND LOW FCST TEMPERATURES ARE CHALLENGING
EARLY IN THE PERIOD GIVEN LOCATIONS AND AMOUNTS OF LINGERING SNOW
COVER AND A GRADUALLY MODIFYING AIRMASS. ANTICIPATED SOME SNOW COVER
SHOULD BE REMAINING OVER THE SOUTHERN THIRD OF THE AREA...SO HAVE
MADE SOME TEMPERATURE MODIFICATIONS TO THESE AREAS. OTHERWISE...
TEMPERATURES SHOULD STILL STRUGGLE TO GET BACK TO NORMAL. PREFERRED
THE COLDER GFS MEAN MOS TEMPERATURES THAT SEEM TO TAKE INTO ACCOUNT
A CHILLY MODIFYING AIRMASS. THE ECMWF IS EVEN COLDER THAN THE
GFS...WITH 850 MB TEMPS STAYING BELOW 0C EXCEPT FOR LATE SUNDAY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 10 AM EDT /9 AM CDT/ THIS MORNING
FOR INZ008-009-012>018.
WINTER STORM WARNING UNTIL 10 AM EDT THIS MORNING FOR INZ020-
022>027-032>034.
MI...NONE.
OH...WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR OHZ004-
005-015-016.
WINTER STORM WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR OHZ024-
025.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT TUESDAY FOR LMZ043-046.
&&
$$
SHORT TERM...JAL
LONG TERM...SKIPPER
UPDATE...MURPHY
AVIATION...AGD
AREA FORECAST DISCUSSION...CORRECTED
NWS NORTHERN INDIANA
125 AM EDT MON MAR 25 2013
.UPDATE...
SLIGHT ADJUDICATION WRT WSW VERBIAGE JUST PRIOR TO 1 AM EDT...AS
EVENT CRESCENDO UPON US AT 05 UTC...WITH FRESHENED WORDING TO RIDE
WELL INTO MORNING DRIVE. SNOWFALL RATES AT 2-2.4 INCHES PR
HOUR...THROUGH BREVITY /20 MINS AT SINGLE POINT/ PER NWD BANDED WAVE
PROPAGATION S/B SAVING FACTOR AGAINST PRODIGIOUS LOCALIZED EXTREMA
GT 1 FOOT. GAVE SLIGHT INCRS IN NWRN OH TO 5-9 INCH RANGE WITH
LOCALLY HIR NEAR ROUTE 30. CONVECTIVE INSTABILITY REALIZED ACRS
NWRN OH/VAN WERT CO. THIS MUCH IN LINE WITH IDYLLIC WEAKNESS WITHIN
THETA-E LAPSE RATES PER YDAY NAM AND NOW WITH 25/00 WRFARW.
FURTHERMORE LTST WRF WELL DEPICTING FORKED TROWAL FM CNTL OH VERTEX
INTO NRN IN AND SECONDARY INCRSGLY DOMINANT/TUCKED TROWAL WITH MORE
SUBSTANTIVE BULK MSTR ACCESS ACRS ECNTL IN INTO WCNTL OH...ROUGHLY
KMIE-KDAY. SINGLED OUT GRANT/BLACKFORD/JAY FOR MOST PROBABLE HIR
ISOLD AMOUNTS...THOUGH MAINTAINED PRIOR/REASONABLE AREAL RANGE GIVEN
IMMINENT COASTAL HANDOFF AND WRN FLANK OF SOLID SNOW WITH TRANSITION
TO A MORE INTERMITTENT CHARACTER IS NOW WELL INTO NWRN IN. PVU FOLD
SPUR NOW ROUNDED INTO VA SUGGESTS DEMARCATION PT FOR RAPID ENERGY
XFER TO FAVORABLE GULF STREAM CYCLOGENESIS HAS BEGUN...WITH RATES
MARKEDLY DIMINISHED BY SUNRISE.
&&
.PREV DISCUSSION... /ISSUED 928 PM EDT SUN MAR 24 2013/
UPDATE...
A VIGOROUS UPPER LEVEL TROUGH WILL CONTINUE TO SHIFT EAST ACROSS
THE OHIO RIVER VALLEY TONIGHT WITH 2330Z WATER VAPOR IMAGERY
PUTTING THE CENTER OF THE UPPER LEVEL CYCLONIC CIRCULATION ACROSS
SOUTHEAST ILLINOIS. IMPRESSIVE UPPER LEVEL DYNAMICS IN PLAY THIS
EVENING IN HIGHLY DIFFLUENT FLOW PATTERN ACROSS NORTHERN
INDIANA/NORTHWEST OHIO. AS THE UPPER LOW SHIFTS
EASTWARD...DEFORMATION BAND SHOULD PIVOT ACROSS SOUTHERN PORTIONS
OF THE FORECAST AREA WITH SEVERAL HOURS OF MODERATE TO HEAVY SNOW
EXPECTED LATE EVENING INTO THE EARLY PORTIONS OF THE OVERNIGHT
HOURS. A STRONG VORT MAX PER WATER VAPOR IMAGERY/RAP
INITIALIZATION ACROSS FAR SOUTHERN INDIANA SHOULD WRAP INTO
SOUTHERN PORTIONS OF THE AREA VIA PARENT UPPER CYCLONIC
CIRCULATION TOWARD 06Z...BUT LIKELY IN A WEAKENING STATE AS IT
ENCOUNTERS STRONGER UPPER LEVEL DEFORMATION FLOW. NAM/GFS
TIME/HEIGHT SECTIONS STILL INDICATING STRONGEST UVM IN THE 00Z-06Z
TIMEFRAME THIS EVENING...WITH AN INCREASINGLY FAVORABLE OVERLAP
TOWARD 03Z OF VERTICAL MOTION AND RELATIVELY DEEP DGZ BETWEEN
750-550 HPA. ELEVATED WEAK STATIC STABILITY ALSO SHOULD MAXIMIZE
RESPONSE FROM FRONTOGENETIC/DPVA FORCING LATE THIS EVENING INTO
EARLY PORTIONS OF OVERNIGHT. ALREADY A FEW REPORTS EARLIER THIS
AFTERNOON/EVENING JUST SOUTH AND SOUTHWEST OF THE FORECAST AREA OF
1 TO 2 INCH PER HOUR SNOWFALL RATES.
OF CONCERN AS DEFORMATION BAND PIVOTS OVERNIGHT...LOW LEVEL
FRONTOGENETIC FORCING MAY REMAIN ANCHORED ACROSS WESTERN PORTIONS
OF THE AREA THAT COULD ACT TO ENHANCE SNOW AMOUNTS. GIVEN ABOVE
SYNOPTIC/MESOSCALE FACTORS...SOME POTENTIAL APPEARS TO EXIST FOR
SOME LOCALLY HIGHER SNOWFALL AMOUNTS IN EXCESS OF 8 INCHES ACROSS
THE FAR SOUTH/SOUTHWEST...BUT CONFIDENCE REMAINS LOW IN
EXTENT/COVERAGE OF THESE TYPE OF ACCUMULATIONS. PREVIOUS FORECAST
APPEARS TO HAVE SITUATION COVERED WELL...AND HAVE MADE JUST A
MINOR UPWARD ADJUSTMENT IN STORM TOTAL ACCUMS ACROSS THE WARNING
AREA...AND TO HIGHLIGHT POSSIBILITY OF LOCALLY HIGHER AMOUNTS.
ONLY OTHER TWEAK TO FORECAST WAS TO INCREASE POPS A BIT MONDAY
MORNING AS ENSEMBLE GUIDANCE APPEARS TO SLOW DEPARTURE OF
WEAKENING DEFORMATION/TROWAL FORCING. NO CHANGES WERE MADE TO THE
CURRENT HEADLINES AT THIS TIME.
PREV DISCUSSION... /ISSUED 337 PM EDT SUN MAR 24 2013/
SHORT TERM...
TONIGHT...MONDAY...MONDAY NIGHT...
LATEST WATER VAPOR IMAGERY SHOWING POTENT UPPER TROUGH AND
ASSOCIATED VORT MAX PUSHING ACROSS MISSOURI THIS AFTERNOON. LOW-MID
LEVEL ASCENT AHEAD OF THIS FEATURE IS RESULTING IN A LARGE SWATH OF
HEAVY SNOW OVER EASTERN MO AND WEST CENTRAL IL. RADAR IMAGERY
DEPICTING CONVECTIVE ELEMENTS EMBEDDED WITHIN THIS SNOW BAND WHICH
MAY ACT TO HINDER MOISTURE TRANSPORT NORTHWARD INTO OUR AREA AS THIS
SYSTEM CONTINUES TO MOVE E/NE THIS EVENING. 12Z RAOBS CONFIRMING
LATEST RAP ANALYSIS SHOWING STRONG UPPER JET TRAVERSING THROUGH THE
BASE OF THIS TROUGH...ASSOCIATED UPPER LEVEL DIVERGENCE EXPECTED TO
AID IN THE CONTINUATION OF HEAVY SNOW BAND AS IT MOVES INTO
CENTRAL/NORTHERN INDIANA TONIGHT. MODELS IN DECENT AGREEMENT IN NE
TRACK OF SFC LOW...BRINGING IT INTO NORTHERN KY BY 00Z MON AND UP
INTO SW OH BY 12Z MON...PLACING OUR SOUTHERN CWA IN FAVORABLE AREA
FOR FOR HEAVY SNOW. KEY COMPONENT IN THE EVOLUTION OF THIS SYSTEM
THAT WILL ACT TO LIMIT SNOW ACCUMULATIONS IS THE EASTWARD
PROGRESSION OF UPPER JET DYNAMICS AND THE RESULTING COASTAL TRANSFER
OF ENERGY. THIS WILL RAPIDLY DISSIPATE OH VALLEY SFC LOW MONDAY IN
FAVOR OF INTENSIFICATION OF COASTAL LOW AS CLOSED UPPER LOW
CONTINUES ON EASTWARD TRACK AND BECOMES NEARLY VERTICALLY STACKED
WITH SFC LOW OVER OH VALLEY 09-12Z MON. THAT SAID...THERE STILL
EXISTS A 12 HOUR WINDOW...00Z-12Z MON...OF FAVORABLE CONDITIONS FOR
ACCUMULATING SNOW AS ALL MODELS IN GOOD AGREEMENT WITH PRODUCING 6-8
INCHES OVER THE FAR SOUTHERN PORTION OF THE CWA AS 80-100M 500MB HT
FALLS WILL REACH UP INTO THE SOUTHERN CWA AS UPPER LOW TRACKS
THROUGH KY OVERNIGHT. AND WHILE MODELS VARY ON DEGREE OF DEEP
MOISTURE AVAILABLE...AMPLE LOW LEVEL MOISTURE ALONG WITH BETTER
ALIGNMENT OF OMEGA AND DGZ THAN PREVIOUS RUNS WILL ALSO FAVOR A GOOD
SHOT AT HVY SNOW FOR AT LEAST A BRIEF PERIOD OF TIME OVERNIGHT
ACROSS THE SOUTHERN TIER OF THE FCST AREA. WILL THEREFORE CONTINUE
WITH WARNING/ADV AREAS AND KEEP NORTHERN TIER WITHOUT HEADLINES AS
DISTINCT CUTOFF IN SNOW EXPECTED NORTH OF US6. IN THE WAKE OF THIS
SYSTEM FLOW WILL GRADUALLY BACK FROM NE TO N/NW LATE IN THE DAY
MONDAY AND BRING CHANCE FOR LES INTO OUR EXTREME NW CWA. DESPITE
UNIFORM NORTHERLY FLOW DOWN THE LONG AXIS OF LAKE MICHIGAN...LACK OF
COLD AIR WILL YIELD MARGINAL/SUB MARGINAL DELTA T AND THEREFORE
HINDER ACCUMULATIONS.
LONG TERM...
TUESDAY THROUGH SUNDAY...INCREASED SNOW CHANCES TUESDAY AND TUESDAY
NIGHT OVER AREAS DOWNSTREAM OF LAKE MICHIGAN AS VERY COLD AIR
CONTINUES TO SPREAD SOUTH OVER THE WESTERN GREAT LAKES REGION. DELTA
T VALUES RATHER MODEST AT 12C TO 14C...BUT A LONG LAKE AXIS FETCH
WITH LIKELY PRECONDITIONING FROM LAKE SUPERIOR SHOULD ALLOW FOR SOME
ORGANIZATION OF SNOW SHOWERS OVER THE LAKE. RAISED SNOWFALL AMOUNTS
TUESDAY...HOWEVER...DAYTIME HEATING SHOULD LIMIT SNOW ACCUMULATIONS.
INVERSIONS HEIGHTS SHOULD FALL LATE TUESDAY NIGHT...BRINGING AN END
TO THE SNOW SHOWERS. HIGH AND LOW FCST TEMPERATURES ARE CHALLENGING
EARLY IN THE PERIOD GIVEN LOCATIONS AND AMOUNTS OF LINGERING SNOW
COVER AND A GRADUALLY MODIFYING AIRMASS. ANTICIPATED SOME SNOW COVER
SHOULD BE REMAINING OVER THE SOUTHERN THIRD OF THE AREA...SO HAVE
MADE SOME TEMPERATURE MODIFICATIONS TO THESE AREAS. OTHERWISE...
TEMPERATURES SHOULD STILL STRUGGLE TO GET BACK TO NORMAL. PREFERRED
THE COLDER GFS MEAN MOS TEMPERATURES THAT SEEM TO TAKE INTO ACCOUNT
A CHILLY MODIFYING AIRMASS. THE ECMWF IS EVEN COLDER THAN THE
GFS...WITH 850 MB TEMPS STAYING BELOW 0C EXCEPT FOR LATE SUNDAY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 10 AM EDT /9 AM CDT/ MONDAY FOR
INZ008-009-012>018.
WINTER STORM WARNING UNTIL 10 AM EDT MONDAY FOR INZ020-022>027-
032>034.
MI...NONE.
OH...WINTER WEATHER ADVISORY UNTIL 2 PM EDT MONDAY FOR
OHZ004-005-015-016.
WINTER STORM WARNING UNTIL 2 PM EDT MONDAY FOR OHZ024-025.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT TUESDAY FOR LMZ043-046.
&&
$$
SHORT TERM...JAL
LONG TERM...SKIPPER
UPDATE...MARSILI
UPDATE...MURPHY
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
125 AM EDT SUN MAR 24 2013
.UPDATE...
SLIGHT ADJUDICATION WRT WSW VERBIAGE JUST PRIOR TO 1 AM EDT...AS
EVENT CRESCENDO UPON US AT 05 UTC...WITH FRESHENED WORDING TO RIDE
WELL INTO MORNING DRIVE. SNOWFALL RATES AT 2-2.4 INCHES PR
HOUR...THROUGH BREVITY /20 MINS AT SINGLE POINT/ PER NWD BANDED WAVE
PROPAGATION S/B SAVING FACTOR AGAINST PRODIGIOUS LOCALIZED EXTREMA
GT 1 FOOT. GAVE SLIGHT INCRS IN NWRN OH TO 5-9 INCH RANGE WITH
LOCALLY HIR NEAR ROUTE 30. CONVECTIVE INSTABILITY REALIZED ACRS
NWRN OH/VAN WERT CO. THIS MUCH IN LINE WITH IDYLLIC WEAKNESS WITHIN
THETA-E LAPSE RATES PER YDAY NAM AND NOW WITH 25/00 WRFARW.
FURTHERMORE LTST WRF WELL DEPICTING FORKED TROWAL FM CNTL OH VERTEX
INTO NRN IN AND SECONDARY INCRSGLY DOMINANT/TUCKED TROWAL WITH MORE
SUBSTANTIVE BULK MSTR ACCESS ACRS ECNTL IN INTO WCNTL OH...ROUGHLY
KMIE-KDAY. SINGLED OUT GRANT/BLACKFORD/JAY FOR MOST PROBABLE HIR
ISOLD AMOUNTS...THOUGH MAINTAINED PRIOR/REASONABLE AREAL RANGE GIVEN
IMMINENT COASTAL HANDOFF AND WRN FLANK OF SOLID SNOW WITH TRANSITION
TO A MORE INTERMITTENT CHARACTER IS NOW WELL INTO NWRN IN. PVU FOLD
SPUR NOW ROUNDED INTO VA SUGGESTS DEMARCATION PT FOR RAPID ENERGY
XFER TO FAVORABLE GULF STREAM CYCLOGENESIS HAS BEGUN...WITH RATES
MARKEDLY DIMINISHED BY SUNRISE.
&&
.PREV DISCUSSION... /ISSUED 928 PM EDT SUN MAR 24 2013/
UPDATE...
A VIGOROUS UPPER LEVEL TROUGH WILL CONTINUE TO SHIFT EAST ACROSS
THE OHIO RIVER VALLEY TONIGHT WITH 2330Z WATER VAPOR IMAGERY
PUTTING THE CENTER OF THE UPPER LEVEL CYCLONIC CIRCULATION ACROSS
SOUTHEAST ILLINOIS. IMPRESSIVE UPPER LEVEL DYNAMICS IN PLAY THIS
EVENING IN HIGHLY DIFFLUENT FLOW PATTERN ACROSS NORTHERN
INDIANA/NORTHWEST OHIO. AS THE UPPER LOW SHIFTS
EASTWARD...DEFORMATION BAND SHOULD PIVOT ACROSS SOUTHERN PORTIONS
OF THE FORECAST AREA WITH SEVERAL HOURS OF MODERATE TO HEAVY SNOW
EXPECTED LATE EVENING INTO THE EARLY PORTIONS OF THE OVERNIGHT
HOURS. A STRONG VORT MAX PER WATER VAPOR IMAGERY/RAP
INITIALIZATION ACROSS FAR SOUTHERN INDIANA SHOULD WRAP INTO
SOUTHERN PORTIONS OF THE AREA VIA PARENT UPPER CYCLONIC
CIRCULATION TOWARD 06Z...BUT LIKELY IN A WEAKENING STATE AS IT
ENCOUNTERS STRONGER UPPER LEVEL DEFORMATION FLOW. NAM/GFS
TIME/HEIGHT SECTIONS STILL INDICATING STRONGEST UVM IN THE 00Z-06Z
TIMEFRAME THIS EVENING...WITH AN INCREASINGLY FAVORABLE OVERLAP
TOWARD 03Z OF VERTICAL MOTION AND RELATIVELY DEEP DGZ BETWEEN
750-550 HPA. ELEVATED WEAK STATIC STABILITY ALSO SHOULD MAXIMIZE
RESPONSE FROM FRONTOGENETIC/DPVA FORCING LATE THIS EVENING INTO
EARLY PORTIONS OF OVERNIGHT. ALREADY A FEW REPORTS EARLIER THIS
AFTERNOON/EVENING JUST SOUTH AND SOUTHWEST OF THE FORECAST AREA OF
1 TO 2 INCH PER HOUR SNOWFALL RATES.
OF CONCERN AS DEFORMATION BAND PIVOTS OVERNIGHT...LOW LEVEL
FRONTOGENETIC FORCING MAY REMAIN ANCHORED ACROSS WESTERN PORTIONS
OF THE AREA THAT COULD ACT TO ENHANCE SNOW AMOUNTS. GIVEN ABOVE
SYNOPTIC/MESOSCALE FACTORS...SOME POTENTIAL APPEARS TO EXIST FOR
SOME LOCALLY HIGHER SNOWFALL AMOUNTS IN EXCESS OF 8 INCHES ACROSS
THE FAR SOUTH/SOUTHWEST...BUT CONFIDENCE REMAINS LOW IN
EXTENT/COVERAGE OF THESE TYPE OF ACCUMULATIONS. PREVIOUS FORECAST
APPEARS TO HAVE SITUATION COVERED WELL...AND HAVE MADE JUST A
MINOR UPWARD ADJUSTMENT IN STORM TOTAL ACCUMS ACROSS THE WARNING
AREA...AND TO HIGHLIGHT POSSIBILITY OF LOCALLY HIGHER AMOUNTS.
ONLY OTHER TWEAK TO FORECAST WAS TO INCREASE POPS A BIT MONDAY
MORNING AS ENSEMBLE GUIDANCE APPEARS TO SLOW DEPARTURE OF
WEAKENING DEFORMATION/TROWAL FORCING. NO CHANGES WERE MADE TO THE
CURRENT HEADLINES AT THIS TIME.
PREV DISCUSSION... /ISSUED 337 PM EDT SUN MAR 24 2013/
SHORT TERM...
TONIGHT...MONDAY...MONDAY NIGHT...
LATEST WATER VAPOR IMAGERY SHOWING POTENT UPPER TROUGH AND
ASSOCIATED VORT MAX PUSHING ACROSS MISSOURI THIS AFTERNOON. LOW-MID
LEVEL ASCENT AHEAD OF THIS FEATURE IS RESULTING IN A LARGE SWATH OF
HEAVY SNOW OVER EASTERN MO AND WEST CENTRAL IL. RADAR IMAGERY
DEPICTING CONVECTIVE ELEMENTS EMBEDDED WITHIN THIS SNOW BAND WHICH
MAY ACT TO HINDER MOISTURE TRANSPORT NORTHWARD INTO OUR AREA AS THIS
SYSTEM CONTINUES TO MOVE E/NE THIS EVENING. 12Z RAOBS CONFIRMING
LATEST RAP ANALYSIS SHOWING STRONG UPPER JET TRAVERSING THROUGH THE
BASE OF THIS TROUGH...ASSOCIATED UPPER LEVEL DIVERGENCE EXPECTED TO
AID IN THE CONTINUATION OF HEAVY SNOW BAND AS IT MOVES INTO
CENTRAL/NORTHERN INDIANA TONIGHT. MODELS IN DECENT AGREEMENT IN NE
TRACK OF SFC LOW...BRINGING IT INTO NORTHERN KY BY 00Z MON AND UP
INTO SW OH BY 12Z MON...PLACING OUR SOUTHERN CWA IN FAVORABLE AREA
FOR FOR HEAVY SNOW. KEY COMPONENT IN THE EVOLUTION OF THIS SYSTEM
THAT WILL ACT TO LIMIT SNOW ACCUMULATIONS IS THE EASTWARD
PROGRESSION OF UPPER JET DYNAMICS AND THE RESULTING COASTAL TRANSFER
OF ENERGY. THIS WILL RAPIDLY DISSIPATE OH VALLEY SFC LOW MONDAY IN
FAVOR OF INTENSIFICATION OF COASTAL LOW AS CLOSED UPPER LOW
CONTINUES ON EASTWARD TRACK AND BECOMES NEARLY VERTICALLY STACKED
WITH SFC LOW OVER OH VALLEY 09-12Z MON. THAT SAID...THERE STILL
EXISTS A 12 HOUR WINDOW...00Z-12Z MON...OF FAVORABLE CONDITIONS FOR
ACCUMULATING SNOW AS ALL MODELS IN GOOD AGREEMENT WITH PRODUCING 6-8
INCHES OVER THE FAR SOUTHERN PORTION OF THE CWA AS 80-100M 500MB HT
FALLS WILL REACH UP INTO THE SOUTHERN CWA AS UPPER LOW TRACKS
THROUGH KY OVERNIGHT. AND WHILE MODELS VARY ON DEGREE OF DEEP
MOISTURE AVAILABLE...AMPLE LOW LEVEL MOISTURE ALONG WITH BETTER
ALIGNMENT OF OMEGA AND DGZ THAN PREVIOUS RUNS WILL ALSO FAVOR A GOOD
SHOT AT HVY SNOW FOR AT LEAST A BRIEF PERIOD OF TIME OVERNIGHT
ACROSS THE SOUTHERN TIER OF THE FCST AREA. WILL THEREFORE CONTINUE
WITH WARNING/ADV AREAS AND KEEP NORTHERN TIER WITHOUT HEADLINES AS
DISTINCT CUTOFF IN SNOW EXPECTED NORTH OF US6. IN THE WAKE OF THIS
SYSTEM FLOW WILL GRADUALLY BACK FROM NE TO N/NW LATE IN THE DAY
MONDAY AND BRING CHANCE FOR LES INTO OUR EXTREME NW CWA. DESPITE
UNIFORM NORTHERLY FLOW DOWN THE LONG AXIS OF LAKE MICHIGAN...LACK OF
COLD AIR WILL YIELD MARGINAL/SUB MARGINAL DELTA T AND THEREFORE
HINDER ACCUMULATIONS.
LONG TERM...
TUESDAY THROUGH SUNDAY...INCREASED SNOW CHANCES TUESDAY AND TUESDAY
NIGHT OVER AREAS DOWNSTREAM OF LAKE MICHIGAN AS VERY COLD AIR
CONTINUES TO SPREAD SOUTH OVER THE WESTERN GREAT LAKES REGION. DELTA
T VALUES RATHER MODEST AT 12C TO 14C...BUT A LONG LAKE AXIS FETCH
WITH LIKELY PRECONDITIONING FROM LAKE SUPERIOR SHOULD ALLOW FOR SOME
ORGANIZATION OF SNOW SHOWERS OVER THE LAKE. RAISED SNOWFALL AMOUNTS
TUESDAY...HOWEVER...DAYTIME HEATING SHOULD LIMIT SNOW ACCUMULATIONS.
INVERSIONS HEIGHTS SHOULD FALL LATE TUESDAY NIGHT...BRINGING AN END
TO THE SNOW SHOWERS. HIGH AND LOW FCST TEMPERATURES ARE CHALLENGING
EARLY IN THE PERIOD GIVEN LOCATIONS AND AMOUNTS OF LINGERING SNOW
COVER AND A GRADUALLY MODIFYING AIRMASS. ANTICIPATED SOME SNOW COVER
SHOULD BE REMAINING OVER THE SOUTHERN THIRD OF THE AREA...SO HAVE
MADE SOME TEMPERATURE MODIFICATIONS TO THESE AREAS. OTHERWISE...
TEMPERATURES SHOULD STILL STRUGGLE TO GET BACK TO NORMAL. PREFERRED
THE COLDER GFS MEAN MOS TEMPERATURES THAT SEEM TO TAKE INTO ACCOUNT
A CHILLY MODIFYING AIRMASS. THE ECMWF IS EVEN COLDER THAN THE
GFS...WITH 850 MB TEMPS STAYING BELOW 0C EXCEPT FOR LATE SUNDAY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 10 AM EDT /9 AM CDT/ MONDAY FOR
INZ008-009-012>018.
WINTER STORM WARNING UNTIL 10 AM EDT MONDAY FOR INZ020-022>027-
032>034.
MI...NONE.
OH...WINTER WEATHER ADVISORY UNTIL 2 PM EDT MONDAY FOR
OHZ004-005-015-016.
WINTER STORM WARNING UNTIL 2 PM EDT MONDAY FOR OHZ024-025.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT TUESDAY FOR LMZ043-046.
&&
$$
SHORT TERM...JAL
LONG TERM...SKIPPER
UPDATE...MARSILI
UPDATE...MURPHY
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
324 AM EDT MON MAR 25 2013
.Short Term (Now - Tuesday)...
Issued at 305 AM EDT Mon Mar 25 2013
The roller-coaster of weather continues this morning. Mother Nature
has shown her full hand to the Ohio Valley over the past 24 hours
with severe thunderstorms, strong winds, heavy rain, and now wintry
precipitation.
The potent upper level disturbance and associated surface low
continue to push off to the northeast. In its wake, strong
westerly winds have enveloped the region, allowing much cooler air
to filter in. The strong band of mid-level frontogenesis associated
with the TROWAL continues to pivot southeast across Indiana and
Illinois. However, this feature is forecast to continue to weaken
as the system becomes a bit more vertically stacked and the surface
low quickly fills in , which is evident by decreasing reflectivities
over the past several hours. However, there still may be a brief
window for some very light accumulations this morning mainly across
southern Indiana and north central Kentucky. With surface
temperatures hovering near freezing and road temperatures in the
upper 30s, do not expect this snowfall to be heavy enough to
accumulate on roadways through the morning hours.
Attention then turns toward late this morning and early this
afternoon, as another upper-level trough axis swings through the
state. As the cold core of the system moves overhead, lapse rates
will steepen substantially this afternoon. Guidance differs
slightly in how the low-level thermal profile will look (with the
05Z RAP showing dry adiabatic lapse rates up to 800mb!), but all are
showing rather impressive low-level instability. With the steep
lapse rates, ELs look to top out around -15C, which would promote
dendritic snow growth. Therefore, think that moderate to locally
heavy snow showers are a good bet today, especially from Louisville
east into the northern Bluegrass.
The age old question then becomes, what will the impact of these
snow showers be. With surface temperatures rising into the middle
30s, much of the snow will be lost to melting. Additionally, road
temperatures will remain rather warm. That being said, the isolated
heavy showers may have the rates to overcome the warmer ground/roads
and cause quick accumulations only to melt soon after the heaviest
precipitation moves out. Additionally, strong westerly winds
combined with the blowing snow will create poor visibilities in the
stronger showers. Therefore, believe there still could be some
impacts from these, even though amounts at any one location are
unlikely to exceed an inch at any one time. For these reasons, will
go ahead and leave the Winter Weather Advisory as is.
The snow showers will linger into the overnight hours into Tuesday
morning, although the intensity should begin to wane. By Tuesday
afternoon, the bulk of the snow showers should push east of the
area. With the expected cloud cover and brisk westerly winds today
and tomorrow, have continued to undercut guidance for highs.
.Long Term (Tuesday Night - Sunday)...
Issued at 300 AM EDT Mon Mar 25 2013
A period of benign weather is in store for the rest of the work week
and into the weekend. High pressure will build eastward from the
Mississippi River valley Wednesday. Models are consistent now in
less of a rain chance with any warm front oriented northwest to
southeast in our vicinity. The best chance...only slight for this
forecast package...looks to be over the southwest forecast area
Friday and Saturday. Then on Sunday the GFS has a cold front close
enough to cause some rains. 12Z Euro and new Euro coming in are not
as quick with this front, so have undercut AllBlend pops a little to
lean more towards the Euro solutions.
Temperatures should fall into the 20s both Wednesday and Thursday
mornings, with daytime highs around 40 Wednesday then increasing to
the 45-50 degree range Thursday. The warmup will continue into the
weekend, with highs by then in the mid to upper 50s, still below
normal for late March, but likely a welcome change for the Easter
weekend.
&&
.Aviation (06Z TAF Issuance)...
Issued at 119 AM EDT Mon Mar 25 2013
A deep area of low pressure will continue to lift slowly northeast
into Ohio overnight. In the wake of this low, cold air will filter
in and change all precipitation over to snow. One heavier snow band
looks to affect KSDF over the next couple of hours before weakening
and shifting over towards KLEX. Within this band, visibilities may
fall down to 1-2 miles and ceilings will fall as well. After
this initial band rolls through, the snow should become a bit more
scattered in nature.
The other concern tonight will be winds. Observations continue to
show winds gusting up around 25 knots, especially across KBWG where
the winds look to remain the highest. However, all sites will see
strong westerly winds through the overnight hours into the day on
Monday.
Snow showers will continue across all sites on Monday, with the best
coverage across KSDF and KLEX. These showers will be moderate to
locally heavy at times, briefly dropping ceilings and visibilities
to IFR. MVFR ceilings and visibilities will be the general rule,
however, so will only carry MVFR conditions through the day with
this package.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING
FOR INZ076>079-083-084-089>092.
KY...WINTER WEATHER ADVISORY UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING
FOR KYZ023>025-028>043-045-048-049.
$$
Short Term.......KD
Long Term........RJS
Aviation.........KD
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
149 AM EDT MON MAR 25 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK ACROSS THE OHIO VALLEY OVERNIGHT. A SECOND
AREA OF LOW PRESSURE WILL MOVE NORTHEAST ALONG THE CAROLINA COAST
TONIGHT...THEN INTENSIFY AS IT TRACKS NORTH ALONG THE MID ATLANTIC
COAST MONDAY AND MONDAY NIGHT. HIGH PRESSURE BUILDS INTO THE AREA
FOR THE MID WEEK PERIOD.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
QUITE THE SN BURST ACRS CNTRL/ERN PORTIONS OF THE FA THIS EVE.
AREA OF MDT/STRONG MID LVL FRONTOGENESIS SHIFTING OFF THE ERN SHR
ATTM...AND THE PCPN CONTG TO DIMINISH IN COVERAGE/INTENSITY AS IT
DOES SO. SFC LO PRES INVOF NC CST...W/ SECOND AREA OF LO PRES IN
ERN KY. ATTENTION TURNS TO THE W WHERE ADDITIONAL PCPN SPREAD INTO
THE CNTRL MTNS. MVMNT OF THAT AREA IS TO THE NNE...AND WHILE THE
AREA OF LO PRES DRIFTS INTO THE MTNS OVRNGT...THE MID/UPR LVL LO
LAGS BEHIND FARTHER W. THE CSTL LO TO MOVE NNE ALG THE
CST...THOUGH NOT ACCOMPANIED BY WDSPRD PCPN.
LATEST RUC13 SUGGESTS THAT MAIN OF PCPN FM THE W PASSES BY TO THE
NW...THOUGH MAY CLIP FAR WNW CTYS AFT MDNGT. OTRW...XPCG SCT LGT
PCPN ELSW OVR THE FA. PTYPE XPCD TO BE MIX OF RA/WET SN (MAYBE A
LTL PL). ADDITIONAL SN ACCUMS WILL BE CONFINED TO NW CTYS...2" OR
LESS...ELSW...A FRESH COATING IS PSBL. ACRS XTRM SE VA INTO NE
NC...SCT -RA/-DZ PSBL (THOUGH WON`T RULE OUT PL). LLVL WEDGE RMNS
FIRMLY IN PLACE OVRNGT. TEMPS TO STAY NRLY STNRY IN THE L/M30S
MOST PLACES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY/...
LOW CONTS TO DEEPEN OFF THE COAST MONDAY. NEXT CONCERN IS FOR WRAP
ARND MSTR ACROSS NRN NECK / LWR MD ERN SHORE CNTYS AS CRITICAL
THICKNESS AND WET BULB HEIGHTS SUGGEST PCPN CHANGES OVR TO SNOW
THERE AFTR 12Z. HOWEVER...SFC TMPS WILL BE ABV FREEZING SO ALTHOUGH
IT WILL CONTINUE TO SNOW ACROSS NRN CNTYS MONDAY...NOT MUCH XPCTD TO
ACCUM SO NO HEADLINE HAS BEEN ISSUED FOR THAT AREA WITH THIS FCST
PACKAGE. LINGERING UPR LVL MSTR RESULTS IN A MORE RAIN/SNOW SHWR
REGIME MON AFTRN. HIGHS IN THE U30S NRN CNTYS TO M40S SERN CSTL
CNTYS.
EVE PCPN ENDS MON NITE. COLD U20S-M30S. ANTHR WEAK S/W PROGGED
ACROSS THE AREA TUE AFTRN. KEPT SLGHT CHC POPS HERE WITH HIGHS
IN THE M-U40S. HIGH PRS FINALLY BUILDS INTO THE RGN FOR THE MID
WEEK PRD. REMAINING CHILLY WITH LOWS TUE NITE IN THE U20S-L30S.
HIGHS WED IN THE U40S-L50S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
12Z GFS/ECMWF IN GENERAL AGREEMENT FOR THE EXTENDED PERIOD...SO
WENT WITH A COMPROMISE OF THE TWO. GOING WITH A DRY FCST ACRS THE
AREA WITH A GRADUAL WARMING TREND. HI PRES WILL GRADUALLY BLD IN
FM THE WNW WED NGT INTO SAT MORNG...THEN THE HI MOVES RIGHT OVR
THE REGION THEN OFF THE CST SAT THRU SUN. HI TEMPS WILL BE IN THE
UPR 40S TO LWR 50S THU...THEN WARM TO THE MID 50S TO LWR 60S SUN.
LOWS WILL BE IN THE UPR 20S TO MID 30S THU AND FRI MORNGS...THEN RANGE
THRU THE 30S SAT AND SUN MORNGS.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
MAINLY IFR CONDITIONS WILL CONTINUE THRU THE MORNG HRS WITH PERIODS
OF LIFR POSSIBLE (ESP AT KRIC) WHERE PRECIP MAY BE HEAVIER. BEST
CHC FOR ANY WINTRY PRECIP (SN/PL) WILL ALSO BE AT KRIC...WITH RA/DZ
EXPECTED ELSEWHERE. NE WINDS OVER THE NEXT FEW HRS WILL TRANSITION
TO N/NW AND INCREASE THIS AFTN AS LO PRES INTENSIFIES JUST OFF THE
COAST AND PULLS NEWRD. ISOLATED SHOWERS OR FLURRIES WILL STILL BE
POSSIBLE TUE...BUT VFR CONDITIONS WILL GENLY PREVAIL. VFR/MAINLY
DRY WED-FRI AS HI PRES SLOWLY BLDS IN FROM THE WEST.
&&
.MARINE...
HAVE LEFT SCA AND GALE WRNG HEADLINES IN PLACE FOR ALL THE WTRS
THRU MON EVENG...BASED ON LATEST MODEL GUIDANCE. STICKING CLS TO
THE LATEST GFS MODEL AND ITS TRACK AND INTENSIFICATION OF THE LO
PRES SYSTEM TNGT THRU MON NGT. THE LO WILL START TO INTENSIFY JUST
OFF THE VA CAPES EARLY MON MORNG...THEN CONTINUE TO STRENGTHEN AS
IT MOVES NE TWD THE NRN ATLC MON THRU MON NGT. ENE WINDS 15 TO 25
KT WITH GUSTS TO ARND 30 KT THIS EVENG/TNGT WILL SHIFT TO THE WNW
LATE MON MORNG INTO MON AFTN. GUSTS TO ARND 35 KT WILL OCCUR OVR
THE CSTL WTRS MON INTO MON EVENG. SEAS WILL BUILD TO 6-9 FT NORTH
DURING MON AND 5-7 FT SOUTH THIS EVENING/TNGT. GRADIENT WEAKENS
LATER MON NIGHT/EARLY TUE...SO HAVE ENDED HEADLINES BY MIDNIGHT
(ALTHOUGH WILL LIKELY NEED TO THEN ISSUE SCA`S FOR THE COASTAL
WATERS FOR LINGERING 5 FT SEAS). OTHERWISE...SUB-SCA CONDITIONS
LIKELY ON TUE...WITH ANOTHER ROUND OF HEADLINES PROBABLY NEEDED
WED-THU...AS HIGH PRESSURE BUILDS IN FROM THE WEST...WHILE LOW
PRESSURE REMAINS OFF THE CANADIAN MARITIMES.
&&
.TIDES/COASTAL FLOODING...
LATEST MDL GUIDANCE SHOWING POTENTIAL FOR MINOR FLOODING AT OCEAN
CITY BY MON EVENG/EARLY TUE MORNG. CONFIDENCE IS LOW HOWEVER...AS
WINDS WOULD BE OFFSHORE/NW BY THAT TIMEFRAME AND NOT SURE HOW WELL
THE MODEL IS HANDLING THE SITUATION. FARTHER SOUTH MDL KEEPS WATER
LEVELS BELOW FLOOD THRESHOLDS. IF WINDS ARE A LITTLE STRONGER THAN
FORECAST...THIS COULD BE UNDERDONE AND MINOR FLOODING WOULD BE
POSSIBLE AT SEWELLS PT WITH MON MORNG HIGH TIDE. EITHER WAY...THIS
SYSTEM LOOKS TO BE TOO FAST MOVING FOR MODERATE OR MAJOR FLOODING
SO NO CSTL WATCH WILL BE ISSUED AT THIS TIME. WILL CONTINUE TO
MONITOR.
&&
.CLIMATE...
LATE MARCH/EARLY APRIL SNOWFALL AT RICHMOND VA (3.5" OR GREATER)
APRIL 3 1915 - 10"
MARCH 26 1971 - 8.4"
MARCH 20 1914 - 7.8"
MARCH 30-APRIL 1 1964 - 7.2"
MARCH 27-28 1947 - 6.9"
MARCH 24-25 1906 - 6.4"
MARCH 21-22 1943 - 4.6"
MARCH 25-26 1900 - 4.5"
MARCH 24 2013 - 3.8" **** UNOFFICIAL THROUGH 00Z/25
MARCH 22 1914 - 3.6"
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...WINTER WEATHER ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR
VAZ048-049.
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ630>638.
GALE WARNING UNTIL 9 PM EDT THIS EVENING FOR ANZ650-652-654-
656-658.
&&
$$
SYNOPSIS...ALB/MPR
NEAR TERM...ALB/MPR
SHORT TERM...MPR
LONG TERM...TMG
AVIATION...MAS
MARINE...TMG
TIDES/COASTAL FLOODING...
CLIMATE...
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
509 AM EDT MON MAR 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 509 AM EDT MON MAR 25 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WEAK MID/UPPER LEVEL NE FLOW
THROUGH THE NRN GREAT LAKES BETWEEN AND LOW OVER THE OHIO VALLEY AND
A RIDGE OVER HUDSON BAY. AT THE SFC...NE WINDS ALSO PREVAILED ACROSS
THE REGION BETWEEN LOW PRESSURE OVER SRN OHIO AND A RIDGE FROM
SASK/MANITOBA INTO THE PLAINS. MARGINAL OVER LAKE INSTABILITY WITH
850 MB TEMPS AROUND -10C ONLY SUPPORTED PATCHY LIGHT SNOW OR
FLURRIES INTO N CNTRL UPPER MI AIDED BY UPSLOPE FLOW (25-30 KT
950-900 MB WINDS) INTO THE HIGHER TERRAIN. UPSTREAM...PERIODS OF -FZDZ
WERE OBSERVED AT CYYU AND CYGQ DURING PERIODS WHERE SATELLITE
IMAGERY SUGGESTED MOISTURE WAS MORE SHALLOW.
AS THE NEXT BATCH OF 925-750 MB MOISTURE MOISTURE MOVES INTO THE
REGION...THE POTENTIAL FOR LIGHT PCPN WILL INCREASE AND CONTINUE
INTO TONIGHT. WITH 850 MB TEMPS AND MIN TEMPS IN THE MOIST LAYER
AROUND -10C...AND THE STRONGEST UPWARD MOTION BELOW THE DGZ...MAINLY
JUST SMALL SNOWFLAKES OR EVEN ICE PELLETS ARE EXPECTED WITH A LOW
SNOW/WATER RATIO. ANY ACCUMULATIONS SHOULD AMOUNT TO AN INCH OR LESS.
GIVEN THE UPSTREAM OBS AND TRENDS FROM THE LAST SEVERAL DAYS...SOME
PATCHY -FZDZ ALSO MAY MIX WITH THE -SHSN/FLURRIES THIS MORNING
BEFORE THE DEEPER MOISTURE BECOMES ESTABLISHED.
AS THE MOIST LAYER BECOMES MORE SHALLOW LATE TONIGHT OVER NCNTRL AND
TEMPS MODERATE TO NEAR -10C AT THE TOP OF MOIST LAYER PER MODEL
SNDGS...-FZDZ WILL AGAIN BE POSSIBLE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 435 AM EDT MON MAR 25 2013
UPPER MICHIGAN WILL REMAIN UNDER THE INFLUENCE OF THE LINGERING
SFC-500MB TROUGH ON TUESDAY. IT WILL BE PUSHED EASTWARD THROUGH MID
WEEK AS THE 500MB HIGH OVER HUDSON BAY SINKS SOUTH INTO THE REGION.
SLOWLY WARMING HIGH TEMPERATURES THROUGH THE PERIOD...WITH ALL AREAS
/OR NEARLY ALL AREAS/ PUSHING ABOVE FREEZING FROM WEDNESDAY ON...AND
INTO THE LOW 40S FOR THE WEEKEND. DRY WEATHER SHOULD BE THE RULE
WEDNESDAY AFTERNOON THROUGH FRIDAY NIGHT AS THE SFC HIGH TO OUR WEST
CENTERS ITSELF ACROSS THE REGION. LOOK FOR SLOWLY DIMINISHING
UPSLOPE CHANCES OF LIGHT SNOW SHOWERS WITH THE SHALLOW MOISTURE AT
OR BELOW 800MB AND DEEPENING INVERSION HEIGHTS. THE NEXT ROUND OF
PRECIPITATION LOOKS TO BE ASSOCIATED WITH THE 500MB LOW OVER HUDSON
BAY SATURDAY SWINGING A SIZABLE TROUGH ACROSS THE NORTHERN PLAINS
THROUGH THE UPPER GREAT LAKES THROUGH THE WEEKEND. THE SFC HIGH WILL
BE SHIFTED SOUTHEAST...AND A COLD FRONT WILL LIKELY SWING ACROSS
WESTERN LAKE SUPERIOR LATE SATURDAY...AND SLOWLY SLIDE EAST OF LAKE
SUPERIOR/UPPER MI SUNDAY BY LATE AFTERNOON. THE 25/00Z ECMWF LOOKS
TO BE A BIT DEEPER AND SLOWER WITH THE PASSAGE OF THE COLD FRONT.
THE 25/00Z GFS KEEP MUCH OF THE ENERGY TO OUR SOUTH...AND AS A
RESULT MUCH OF THE PRECIPITATION. STILL COULD GET AROUND 0.05-0.2IN
OF LIQUID OUT OF THE FRONTAL PASSAGE.
TEMPERATURES FOR THE FIRST HALF OF THE WEEKEND WERE WARMED
SLIGHTLY...WITH A CONTINUED NEED FOR MIXED PRECIPITATION AS HIGH
TEMPERATURES HOVER AROUND 40F. WAA WILL RESULT IN 850MB TEMPS RISING
FROM AROUND -7C AT 12Z FRIDAY TO A CWA AVERAGED -1.5C BY 00Z
SUNDAY...AND POSSIBLY UP TO 0C NEAR MENOMINEE AT 06Z SUNDAY. WAS A
BIT HESITANT TO JUST HAVE RAIN IN THE FORECAST FOR SATURDAY
NIGHT...GIVEN THE TIME OF DAY AND THE FACT THAT IT WAS DAY 5-6...BUT
WITH LOWS NEAR 32F ALL RAIN WOULD BE A SERIOUS POSSIBILITY. LATER
SHIFTS WILL HAVE PLENTY OF TIME TO REDEFINE THE COVERAGE AREA OF
BOTH RAIN AND SNOW FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 127 AM EDT MON MAR 25 2013
AS MOISTER AIR ARRIVES FM ONTARIO EARLY THIS MRNG IN PREVAILING CYC
NNE FLOW...EXPECT LO CLDS/MVFR CIGS TO BECOME THE RULE AT ALL 3 TAF
SITES. THERE MAY BE SOME -SHSN/-FZDZ AS WELL...ESPECIALLY AT IWD/SAW
WHERE THE FLOW PRESENTS A BETTER UPSLOPE WIND COMPONENT. ALTHOUGH
DAYTIME HEATING ON MON AFTN MIGHT RESULT IN SOME IMPROVEMENT IN THE
AFTN...DEEPER MSTR THAN ON SUN SHOULD MAINTAIN THE MVFR CIGS. THE
ARRIVAL OF EVEN DEEPER MSTR TNGT IN THE PRESENCE OF DIURNAL COOLING/
CYC NNE FLOW THAT FAVORS LK EFFECT PCPN INDICATES MORE -SHSN/MVFR
CIGS WL LINGER.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 509 AM EDT MON MAR 25 2013
HIGH PRESSURE IN PLACE OVER THE NORTHERN PLAINS AND LOW PRESSURE
MOVING EASTWARD ACROSS THE TENNESSEE VALLEY WILL LEAD TO A TIGHT
PRESSURE GRADIENT OVER LAKE SUPERIOR THROUGH TUESDAY. THIS WILL
RESULT IN NORTHERLY WINDS 15 TO 25 KNOTS. FOR TUESDAY AFTERNOON AND
BEYOND...HIGH PRESSURE WILL SPRAWL ACROSS THE GREAT LAKES...KEEPING
WINDS BELOW 20 KNOTS OUT OF THE NORTH AND WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1153 PM CDT SUN MAR 24 2013
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
221 PM CDT SUN MAR 24 2013
SNOW COMES TO AN END THIS EVENING WITH DRY AND BELOW NORMAL
TEMPERATURES EXPECTED FOR THE EARLY HALF OF THE WEEK.
CURRENTLY...LIGHT SNOW IS FALLING ACROSS PORTIONS OF THE REGION AS
A PAIR OF CLOSED MID LEVEL LOWS TRACK NEAR THE REGION. THE MORE
POTENT OF THESE LOWS IS MOVING INTO SOUTHERN ILLINOIS WHILE THE
OTHER LOW HAS STALLED OUT ACROSS THE DAKOTAS. A COUPLE BANDS OF
SNOW DEVELOPED ACROSS THE REGION THIS AFTERNOON WHERE THE LIFT
FROM THE TROUGH WAS STRONG ENOUGH TO SATURATE THROUGH THE COLUMN.
AS THE LIFT WEAKENS TONIGHT AND DRY MID LEVEL AIR ADVECTS IN FROM
THE NORTH...EXPECT THAT THE SNOW WILL QUICKLY COME TO AN END FROM
NORTH TO SOUTH. THE 24.16Z HRRR KEEPS THIS SNOW ACROSS PORTIONS OF
NORTHEAST IOWA AND SOUTHEAST MINNESOTA THROUGH 5Z...WHICH APPEARS
TO BE REASONABLE GIVEN RECENT TRENDS. OVERALL IMPACT OF THIS SNOW
HAS BEEN ON THE LOW SIDE WITH ROAD TEMPERATURES IN THE 40 TO 50F
RANGE THIS AFTERNOON WITH MUCH OF THE SNOW MELTING ON CONTACT
WITH THE ROADS. HOWEVER...AS THE SUN AND TEMPERATURES DROP
TONIGHT...SOME OF THE WET ROADS COULD HAVE SOME ICY PATCHES FORM
IF THEY DO NOT DRY OFF FIRST. CLOUD COVER WILL REMAIN OVERCAST
THROUGH THE NIGHT AS LOW AND HIGH LEVEL MOISTURE CONTENT REMAINS
FAIRLY HIGH.
WITH THE DRY NORTHWEST FLOW IN PLACE THROUGH MID WEEK FROM THE
SURFACE THROUGH THE UPPER PORTIONS OF THE ATMOSPHERE...THE MAIN
FORECAST CHALLENGES WILL BE WITH CLOUD COVER AND TEMPERATURES. HOW
THE TEMPERATURES PAN OUT WILL DIRECTLY TIE INTO HOW MUCH CLOUD
COVER THERE IS. BASED ON 24.12Z NAM/GFS RH FIELDS AND
SOUNDINGS...IT APPEARS THAT THE CLOUDS SHOULD LINGER THROUGH
TUESDAY BEFORE A RIDGE OF HIGH PRESSURE MOVES IN FROM THE WEST
TUESDAY NIGHT. THERE COULD BE A FEW BREAKS IN THE CLOUDS ON
TUESDAY...BUT OVERALL BELIEVE THAT THE SKIES WILL MAINLY BE CLOUDY
UNTIL THE RIDGE GETS IN. 850MB TEMPERATURES DO DROP SLIGHTLY OVER
THE NEXT COUPLE DAYS...FROM -10C TO -12C...BUT THEN START TO
REBOUND GOING INTO WEDNESDAY AS THE RIDGE AXIS APPROACHES FROM THE
WEST. BASED ON THE GRADUALLY THINNING CLOUD COVER...HAVE GONE
WITH A SIMILAR GRADUAL INCREASE IN TEMPERATURES.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
221 PM CDT SUN MAR 24 2013
THIS WARMING TREND WILL CONTINUE THROUGH THE REST OF THE WEEK AS
THE LONG WAVE UPPER LEVEL TROUGH OVER THE EASTERN HALF OF THE US
PROGRESSES EASTWARD AND UPPER LEVEL RIDGING TRIES TO DEVELOP
ACROSS THE CENTRAL US. WARMER LOW LEVEL AIR WILL ADVECT INTO THE
REGION FROM THE SOUTHWEST WITH 850MB TEMPERATURES REACHING +2C BY
SATURDAY AHEAD OF THE NEXT SYSTEM TO IMPACT THE REGION. THIS NEXT
SYSTEM THAT THE 24.12Z GFS/ECMWF BRING INTO THE REGION ON
SATURDAY/SATURDAY NIGHT IS CURRENTLY OFF THE WEST COAST OF ALASKA
AND APPEARS TO STALL OUT OVER THE PACIFIC NW AROUND MID WEEK.
THERMAL PROFILES FROM BOTH THE 24.12Z GFS/ECMWF SUGGEST THAT THE
PRECIPITATION WILL REACH THE GROUND AS RAIN DUE TO A DEEP WARM
LAYER FROM THE SURFACE UP TO 800MB. WITH FORECAST HIGH
TEMPERATURES OF AROUND 50F FRIDAY INTO SUNDAY AND A PERIOD OF RAIN
COMING THROUGH...WILL HAVE TO WATCH FOR SOME POTENTIAL FLOODING ON
AREA RIVERS SHOULD THIS FORECAST CONTINUE TO TREND THIS WAY.
&&
.AVIATION...THROUGH 06Z TUESDAY
1153 PM CDT SUN MAR 24 2013
AS EXPECTED...CLEARING THAT WAS OVER UPPER MICHIGAN EARLY IN THE
EVENING HAS MOVED ITS WAY SOUTH AND AS OF 05Z ENCOMPASSES MUCH OF
NORTHERN WISCONSIN. THE CLEARING IS MOVING SOUTHWEST
QUICKLY...THUS HAVE CLOUDS SCATTERING OUT AT BOTH TAF SITES BY
08Z. HEADING INTO THE AFTERNOON HOURS...DAYTIME HEATING PLUS
MOISTURE FROM SNOW MELT AND COOLER AIR ALOFT MAY BE ENOUGH TO
RESULT IN BROKEN STRATOCUMULUS WITH VFR CEILINGS. AS WINDS TURN
MORE NORTHWESTERLY IN THE EVENING...ASSOCIATED WITH HIGH PRESSURE
SLOWLY BUILDING IN FROM THE DAKOTAS...DRIER AIR ON THESE WINDS
COMBINED WITH NOCTURNAL COOLING SHOULD ALLOW THE STRATOCUMULUS TO
DISSIPATE. REGARDING THOSE WINDS...GENERALLY 10 TO 15 KT SPEEDS
ARE EXPECTED THROUGH THE DAY TODAY...HIGHEST DURING THE AFTERNOON
WHERE SOME GUSTS TO 20 KT CANNOT BE RULED OUT. WINDS WILL DIMINISH
IN THE EVENING WITH LOSS OF HEATING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
221 PM CDT SUN MAR 24 2013
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1124 PM CDT SUN MAR 24 2013
.UPDATE...
BAND OF WARM ADVECTION/FRONTOGENETICALLY-DRIVEN SNOW HAS DROPPED
SOUTH OF THE CWA AS LOW PULLS AWAY. WILL PUT INT FLURRIES AS
SWITCH TO VCP 31 REVEALING LIGHT RETURNS OVER CWA.
GFS REMAINS THE MOST ROBUST WITH DEVELOPING A LAKE-BAND WITH
HIGHER EQUILIBRIUM LEVELS...THOUGH RAP ALSO SHOWING DECENT EL
HEIGHTS AND 1000-900 MB ALONG-SHORE CONVERGENCE BY 12Z MONDAY. WRF
BASED MODELS ALSO SHOW LAKE BAND WITH HRRR ALSO SHOWING A BAND
DEVELOPING BY 15Z MONDAY. WILL KEEP MENTION OF LAKE- EFFECT SNOW
SHOWERS GOING FROM PREVIOUS FORECAST. GUSTY NORTH WINDS CONTINUE
OVERNIGHT...THOUGH NOT QUITE AS STRONG AS EARLIER THOUGHT.
&&
.AVIATION/06Z TAFS/...
CIG HEIGHTS WILL HOVER RIGHT AT THE VFR/MVFR BREAK POINT OVERNIGHT
AS MOISTURE CONVERGENCE ALONG WEAK INVERTED TROUGH OVER REGION
FIGHTS WITH DRY AIR ADVECTING IN FROM THE NORTH AND NORTHEAST.
FLOW OFF THE LAKE WILL BRING SOME MOISTURE ENHANCEMENT TO EASTERN
SITES THAT COULD HOLD THEIR CIGS BELOW 3K FT....THOUGH MOS GUIDANCE
INDICATES NOT. UPSTREAM OBS FAVOR THE MORE OPTIMISTIC GUIDANCE AND
WILL BE FOLLOWED...WITH NECESSARY ADJUSTMENTS. GUSTY NORTH WINDS
UP TO 25 TO 30 KTS EARLY IN THE FORECAST WILL SLOWLY SUBSIDE AS
LOW PULLS AWAY.
&&
.MARINE...
CANCELLED GALE WARNING IN THE SOUTHERN ZONE AS WINDS HAVING A HARD
TIME REACHING 30 KNOTS AND GRADIENT SLACKENING AS LOW PULLS AWAY.
COULD STILL SEE SOME 30 TO 35KT GUSTS...BUT NOT FREQUENT ENOUGH TO
CONTINUE WARNING. SMALL CRAFT ADVISORY CONTINUES FOR ALL ZONES
INTO THE OVERNIGHT MONDAY NIGHT.
&&
.PREV DISCUSSION... /ISSUED 322 PM CDT SUN MAR 24 2013/
SHORT TERM...
TONIGHT...FORECAST CONFIDENCE MEDIUM.
WEAK ONGOING 500MB VORTICITY ADVECTION IN SOUTHERN WISCONSIN DUE TO
THE PROXIMITY OF THE CLOSED UPPER LOW MOVING FROM SOUTHERN IL UP
THROUGH THE OHIO RIVER VALLEY IS LENDING SUPPORT TO PERIODS OF LIGHT
SNOW OVER SOUTHERN WISCONSIN THIS AFTERNOON. THE SEMI-PERSISTENT
ENHANCED REFLECTIVITY BAND APPARENT ON RADAR FROM SOUTHERN COLUMBIA
COUNTY TO SOUTHERN OZAUKEE COUNTY IS THE RESULT OF AN AREA OF
700-600MB WARM AIR ADVECTION AND FRONTOGENESIS. THE WAA AND FGEN
BAND IS FORECAST BY MESOSCALE MODELS TO GRADUALLY WEAKEN AND SLIP
SOUTHEASTWARD THIS EVENING.
REPORTS OF VISIBILITIES DOWN TO A QUARTER MILE HAVE BEEN ASSOCIATED
WITH THE AREAS OF HIGHER REFLECTIVITY. THE BANDS ARE MOVING
SLOWLY...SO LOCATIONS UNDER A BAND COULD SEE AN INCH ACCUMULATION
WITHIN AN HOUR.
VERY DRY AIR IN FAR SOUTHEAST WISCONSIN INCLUDING SOUTHERN MILWAUKEE
COUNTY AND ALL OF RACINE AND KENOSHA COUNTIES HAS KEPT ALL SNOW OUT
OF THIS AREA ALL DAY TODAY. EXPECT THAT TO CHANGE THIS EVENING AS
THE WINDS BECOME NORTHERLY AND THAT WAA/FGEN BAND SHIFTS SOUTHEAST.
RECENT AMDAR AIRCRAFT SOUNDINGS FROM MITCHELL MILWAUKEE AIRPORT SHOW
850MB TEMP OF -8 TO -9C WHICH WOULD GIVE A LAKE-850MB TEMP
DIFFERENCE OF 10 TO 11C...WHICH IS MARGINAL FOR LAKE EFFECT SNOW
PRODUCTION. EXPECT THE LAKE TO CONTRIBUTE VERY LIGHT SNOW TO
LAKESHORE AREAS AT TIMES TONIGHT AFTER THE WINDS BECOME NNE TO NORTH
AND THERE IS A LONG ENOUGH FETCH OVER LAKE MICHIGAN TO ACTUALLY
DEVELOP A BAND. MESOSCALE MODELS ALL SHOW VERY LIGHT LAKE EFFECT
SNOW BANDS IN THE FORECAST QPF AND REFLECTIVITY FIELDS. AS FOR
TIMING...MOST LIKELY SCENARIO AT THIS TIME IS THAT THE EXISTING
EAST-TO-WEST BAND WILL SHIFT SOUTH AS IT BECOMES ORIENTED NE TO SW
OVER MKE/RAC/ENW DURING THE EVENING HOURS. THEN ANOTHER LAKE BAND
WILL DEVELOP NORTH OF SHEBOYGAN AND GRADUALLY MOVE SOUTHWARD ALONG
THE LAKESHORE BETWEEN MIDNIGHT AND 8 AM.
MONDAY...FORECAST CONFIDENCE MEDIUM.
LIGHT LAKE EFFECT SNOW SHOWERS COULD PERSIST IN THE LAKESHORE
COUNTIES IN THE MORNING...BUT EXPECTING ANYTHING LEFT BY THE
AFTERNOON TO SHIFT OFFSHORE OR DISSIPATE AS THE 1000-850MB WINDS
TURN DUE NORTH.
STEEP LOW LEVEL LAPSE RATES WITHIN CYCLONIC FLOW AROUND EXITING LOW
PRESSURE AND LINGERING LOW LEVEL MOISTURE SHOULD BE SUFFICIENT TO
PRODUCE FLURRIES ACROSS MUCH OF THE AREA MONDAY AFTERNOON. WE COULD
SEE SOME BREAKS IN THE CLOUDS DURING THE DAY DUE TO THE STRONG MARCH
SUN...BUT EXPECTING MOSTLY CLOUDY SKIES OVERALL. MAX TEMPS SHOULD
REACH THE MID 30S.
MONDAY NIGHT AND TUESDAY...FORECAST CONFIDENCE MEDIUM.
THE MODELS CONTINUE A GENERAL MID/UPPER TROUGH OVER THE GREAT LAKES
WITH A WEAK UPSTREAM SHORTWAVE AFFECTING SOUTHERN WISCONSIN ON
TUESDAY. THE MAIN JET WILL BE ACROSS THE SOUTHEAST U.S. SO NO
RELIEF IN THE COLDER TEMPERATURES...WITH 1000 TO 500 MB THICKNESS
AROUND 522 TO 525 DECAMETERS.
THERE WILL STILL BE A CHANCE OF LAKE EFFECT SNOW SHOWERS OVER
SOUTHEAST WISCONSIN MONDAY EVENING...BUT THE LOW LEVEL WINDS
BECOME MORE NORTH...DIMINISHING THE SNOW CHANCES. THERE IS STILL
SUFFICIENT MOISTURE BELOW 800 MB FOR STRATOCUMULUS AND POTENTIALLY
SOME SNOW SHOWERS TUESDAY...WITH LAPSE RATES 7 TO 8 CELSIUS/KM
BELOW 850 MB.
TUESDAY NIGHT AND WEDNESDAY...FORECAST CONFIDENCE MEDIUM.
THE MODELS CONTINUE A WEAK WEST/NORTHWEST FLOW AT 500 MB WITH
A WEAK SHORTWAVE MOVING TOWARD THE LAKE SUPERIOR REGION.
AT THE SURFACE THE MODELS HAVE A WEAK HIGH ACROSS THE UPPER
MISSISSIPPI VALLEY AND WISCONSIN. ONLY A SLIGHT MODERATION IN
THICKNESS VALUES AND TEMPERATURES IS EXPECTED WITH WEAK NORTH LOW
LEVEL FLOW PERSISTING.
LONG TERM...
THURSDAY AND FRIDAY...FORECAST CONFIDENCE MEDIUM.
THE MODELS CONTINUE THE WEST/NORTHWEST FLOW AT 500 MB WITH A SLIGHT
DIFFERENCE IN TIMING OF ANOTHER SHORTWAVE MOVING ACROSS THE LAKE
SUPERIOR AREA THURSDAY AND ACROSS THE GREAT LAKES FRIDAY.
AT THE SURFACE THE GFS/ECMWF/GEM CONTINUE THE WEAK HIGH ACROSS
WISCONSIN WITH THE GRADUAL MODERATION IN TEMPERATURES CONTINUING.
SATURDAY AND SUNDAY...FORECAST CONFIDENCE MEDIUM.
THE MODELS STILL CONTINUE THE WEST/NORTHWEST FLOW AT 500 MB WITH
A SLIGHT DIFFERENCE IN TIMING OF ANOTHER SOMEWHAT STRONGER SHORTWAVE
MOVING ACROSS WISCONSIN.
AT THE SURFACE THE 12Z GFS AND 00Z ECMWF BRINGS A TROUGH OF LOW
PRESSURE ACROSS SOUTHERN WISCONSIN MAINLY SATURDAY NIGHT.
THICKNESS/850 MB VALUES INDICATE A RAIN SNOW MIX WITH MAINLY RAIN
SOUTHWEST AREAS. THE 12Z ECMWF IS A LITTLE SLOWER EXTENDING THE
CHANCE OF PRECIPITATION INTO SUNDAY.
AVIATION/00Z TAFS/...
SLOW-MOVING AREAS OF HEAVIER SNOW APPARENT ON RADAR IMAGERY COULD
PRODUCE A QUICK INCH OF SNOW IN AN HOUR. VISIBILITIES DOWN TO A HALF
MILE HAVE BEEN REPORTED WITHIN THESE BANDS. THIS BAND IS EXPECTED TO
GRADUALLY SHIFT SOUTHEASTWARD AND DIMINISH BY EARLY EVENING. MVFR
CEILINGS WILL PREVAIL TONIGHT AND IMPROVE TOWARD MORNING. CIGS COULD
DIP TO IFR IN THE HEAVIER SNOW BANDS.
THE SURFACE TO 5000 FT FLOW INCREASES TONIGHT AND SWITCHES FROM EAST
TO NORTHEAST. INSTABILITY OVER THE LAKE WILL HELP PRODUCE LAKE
EFFECT SNOW SHOWERS NEAR LAKE MICHIGAN THAT BEGIN NORTH OF SHEBOYGAN
AROUND MIDNIGHT AND SLIP SOUTHWARD THROUGH MONDAY MORNING.
ACCUMULATIONS TONIGHT SHOULD BE SPOTTY AND LESS THAN AN INCH.
MORE FLURRIES AND MVFR CIGS COULD DEVELOP MONDAY AFTERNOON AT ALL
TAF SITES.
MARINE...
HIGHER WINDS ARE DEVELOPING OVER SOUTHERN LAKE MICHIGAN LATE THIS
AFTERNOON AND WILL PERSIST THROUGH MUCH OF TONIGHT. GALE WARNING IN
EFFECT FOR THE SOUTHERN MARINE ZONE FROM WIND POINT TO WINTHROP
HARBOR FROM 22Z THROUGH 09Z TONIGHT. WILL NEED TO RAMP DOWN TO A
SMALL CRAFT ADVISORY AGAIN AFTER THAT EXPIRES.
A SMALL CRAFT ADVISORY IS IN EFFECT ELSEWHERE THROUGH MONDAY NIGHT
DUE TO BRISK NORTHEAST WINDS AND HIGH WAVES. THE BRISK WINDS WILL BE
PRODUCED BY STRONG LOW PRESSURE SLOWLY MOVING ALONG THE OHIO RIVER
VALLEY.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM CDT TUESDAY FOR LMZ643>646.
&&
$$
UPDATE...REM
TONIGHT/MONDAY AND AVIATION/MARINE...MRC
MONDAY NIGHT THROUGH SUNDAY...HENTZ
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1117 AM EDT MON MAR 25 2013
.SYNOPSIS...
LOW PRESSURE INTENSIFYING SOUTH OF LONG ISLAND TODAY BRUSHES THE
REGION WITH WINTRY WEATHER. THE LOW TRACKS EAST TONIGHT ALLOWING
CANADIAN HIGH PRESSURE TO BUILD IN. THE HIGH WILL CONTROL OUR
WEATHER INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
MOST DIFFICULT FORECAST TO START THE WEEK. 993 HPA LOW EAST OF
THE DELMARVA AS OF 12 UTC WILL DEEPEN RAPIDLY THROUGH THE DAY.
HEAVY WET SNOW OVER CENTRAL AND SOUTHERN NJ HAS LOWERED TEMPS TO
FREEZING THERE.
LOCALLY...13 UTC TEMPS ARE NEAR 40 F WITH DEWS IN THE MID 20S. THIS
GIVES ME A WET BULB OF 34-35 F. PCPN IS HAVING A HARD TIME
MAKING NORTHWARD PROGRESS INTO THE DRY AIR.
TIME LAGGED RAPID REFRESH (RR) SUPPORTS HEAVIEST PCPN STAYING
JUST SOUTH OF THE REGION. SUBJECTIVELY...THIS TYPICALLY GETS
DISPLACED NW OF THE DEPICTED MODEL QPF. LATEST HRRR IS A BIT SOUTH
OF THE RR.
TEMPS ARE NEAR MAX AT THIS TIME AND WILL DROP TO WET BULB THIS
AFTN AS PCPN MOVES IN.
P-TYPE IS MAINLY WET SNOW...BUT WITH TEMPS ABOVE
FREEZING...ACCUMULATION IS DIFFICULT UNLESS HEAVIER PCPN MAKES IT
FURTHER NORTH THAN FORECAST.
HAVE CANCELED THE SNOW ADVISORY WITH THE BELIEF THAT EVEN IF WE
WERE TO REACH 3 INCHES...LIMITED IMPACT IS EXPECTED DUE TO TEMPS
ABOVE FREEZING.
&&
.SHORT TERM /TUESDAY/...
BY TUESDAY MORNING THE LOW WILL BE WELL EAST OF THE REGION WITH
PRECIPITATION HAVING ENDED. AN UPPER LOW...OR ELONGATED TROUGH WILL
REMAIN TO THE NORTH THAT ROTATES SOUTH DURING THE DAY. A RATHER
VIGOROUS VORT MAX ROTATES INTO THE REGION BY THE AFTERNOON. SO WILL
KEEP THE CHANCE OF FLURRIES ACROSS THE NORTHERN TIER...AND DRY
SOUTH. A CHILLY AIR MASS WILL REMAIN IN PLACE WITH A NORTHWEST FLOW
BEHIND THE LOW. LEANED TOWARD THE COOLER MET GUIDANCE FOR HIGHS WITH
A BLEND OF THE CURRENT FORECAST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
A LARGE AREA OF UPPER LEVEL LOW PRESSURE REMAINS JUST NORTH AND EAST
OF THE AREA THROUGH MUCH OF THE WEEK. A PERSISTENT NORTHWESTERLY
FLOW CONTINUES WITH PARTLY TO MOSTLY CLOUDY STRATO CU OVER THE AREA
THROUGH THE WEEKEND...MOSTLY WITH DAYTIME INSTABILITY. AS SHORTWAVES
ROTATE AROUND THIS LOW...CAN EXPECT FLURRIES/LIGHT SNOW INLAND AND
LIGHT RAIN SHOWERS...EVEN FLURRIES AT NIGHT...FARTHER EAST MANY
TIMES DURING THE WEEK. STRONGEST SHORTWAVES LOOK TO MOVE THROUGH
WEDNESDAY MORNING AND THURSDAY NIGHT. NOT CONFIDENT ENOUGH ON THE
TIMING TO WARRANT ANY MORE THAN SLIGHT CHANCE POPS. TEMPERATURES
WILL REMAIN IN THE UPPER 40S ON WEDNESDAY AND SLOWLY WARM BY THE
WEEKEND. LOWS REMAIN BELOW NORMAL...LOWER TO UPPER 30S THROUGH THE
WEEK.
THE UPPER LOW FINALLY PUSHES EAST OF THE AREA BY FRIDAY WITH A LARGE
AREA OF SURFACE HIGH PRESSURE PRESSING IN FROM THE WEST. SLIGHT
RIDING ALOFT WILL ALLOW TEMPERATURES TO WARM SLIGHTLY...TO NEAR
NORMAL VALUES. HIGHS WILL RANGE FROM THE UPPER 40S TO LOWER 50S WITH
HIGHS SUNDAY A DEGREE OR TWO WARMER. WINDS WILL BE LIGHT THROUGH THE
WEEKEND AND TURN SOUTHERLY SUNDAY NIGHT AHEAD OF A LOW PRESSURE
SYSTEM.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
LOW PRES PASSES SOUTH OF LONG ISLAND TODAY.
LIGHT PRECIP...EITHER WET SNOW OR A SNOW/RAIN MIX...IS JUST ABOUT
TO ENTER THE NYC METRO AREA. AT THE NYC METRO TERMINALS...FLIGHT
CAT SHOULD DROP TO LOW END VFR OR MVFR WITH ONSET OF THIS
PRECIP...THEN TO IFR THIS AFTERNOON. PRECIP WILL TAKE LONGER TO
SPREAD FARTHER NE INTO THE LOWER HUDSON VALLEY...LONG ISLAND AND
SOUTHERN CT. IFR LIKELY TO CONTINUE INTO THE EVENING AS PRECIP
RATES INCREASE AND LOW LEVELS COOL OFF.
HAVE BACKED OFF ON STRENGTH OF WINDS FOR THIS AFTERNOON...WITH
PEAK GUSTS IN THE 25-30 KT RANGE.
NO MORE THAN A SLUSHY COATING OF ACCUMULATION EXPECTED ON RUNWAYS
AT THE NYC METRO TERMINALS AND KHPN/KBDR/KGON THROUGH THIS EVENING
DUE TO LIGHT SNOWFALL RATES AND WARM GROUND TEMPS...MAYBE UP TO AN
INCH AT KISP.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: A BRIEF GUST UP TO 30 KT POSSIBLE INTO THIS
AFTERNOON.
KJFK FCSTER COMMENTS: VSBY IN SNOW COULD DROP BRIEFLY TO 1SM AT
TIMES THIS AFTERNOON. A BRIEF GUST JUST OVER 30 KT POSSIBLE INTO
THIS AFTERNOON.
KLGA FCSTER COMMENTS: A BRIEF GUST UP TO 30 KT POSSIBLE INTO THIS
AFTERNOON.
KTEB FCSTER COMMENTS: NO UNSCHED AMD EXPECTED.
KHPN FCSTER COMMENTS: ONSET OF SNOW AND LOWER FLIGHT CAT COULD BE
1-2 HR LATER THAN FCST.
KISP FCSTER COMMENTS: ONSET OF SNOW AND LOWER FLIGHT CAT COULD BE
UP TO AN HOUR LATER THAN FCST. A BRIEF GUST JUST OVER 30 KT
POSSIBLE THIS AFTERNOON.
.OUTLOOK FOR 12Z TUE THROUGH FRI...VFR. GUSTY NW WINDS WED NIGHT.
&&
.MARINE...
WITH A DEEPENING LOW PRESSURE SYSTEM MOVING SOUTH AND EAST OF THE
WATERS TODAY AND TONIGHT WINDS AND GUSTS ARE EXPECTED TO INCREASE TO
GALE FORCE ON ALL THE FORECAST WATERS BY AROUND NOON TODAY. AS THE
STORM BEGINS TO TRACK EAST OF THE WATERS TONIGHT WINDS WILL DIMINISH
FROM WEST TO EAST...WITH WINDS BELOW GALE LATE THIS EVENING. THERE
IS SOME UNCERTAINTY AS TO HOW STRONG THE WINDS WILL BE IN LONG
ISLAND SOUND AND MAY PEAK JUST BELOW GALE FORCE. THE BEST AREA OF
GALE WINDS WILL BE ACROSS THE EASTERN SOUND AND PECONIC AND
GARDINERS BAYS. THERE WILL BE A FEW HOURS OF SMALL CRAFT GUSTS INTO
EARLY TUESDAY MORNING...THEN WINDS DIMINISH BELOW. SEAS ON THE OCEAN
WILL REMAIN AT OR ABOVE 5 FT INTO TUESDAY EVENING.
WINDS AND WAVES SUBSIDE BELOW SCA CRITERIA BY WEDNESDAY AS THE
SURFACE LOW CONTINUES TO MOVE EAST. MARGINAL SCA GUSTS ARE POSSIBLE
WEDNESDAY INTO THURSDAY AS THE PRESSURE GRADIENT TIGHTENS BETWEEN AN
OFFSHORE LOW AND APPROACHING HIGH PRESSURE. WINDS THEN SUBSIDE BELOW
SCA CRITERIA AND REMAIN THERE THROUGH THE WEEKEND.
&&
.HYDROLOGY...
LIQUID QPF OF AROUND A HALF INCH LIKELY FROM NORTHEASTERN NEW
JERSEY...ACROSS NYC...AND LONG ISLAND WITH JUST AROUND A TENTH
ACROSS THE NORTHERN TIER TODAY AND TONIGHT. THE PRECIPITATION WILL BE
IN THE FORM OF SNOW.
&&
.TIDES/COASTAL FLOODING...
MINOR COASTAL FLOODING EXPECTED DURING THE TIMES OF HIGH TIDE THIS
EVENING...FROM AROUND 7 PM TO MIDNIGHT...WITH SURGE OF AROUND 2 TO 2
1/2 FT. THE MAIN CONCERN IS ALONG THE SOUTH SHORE BAYS OF LONG
ISLAND...QUEENS...AND BROOKLYN AND PECONIC/GARDINERS BAYS. EASTERLY
SWELLS WILL LIKELY ENHANCE SURGE ALONG THE EASTERN PORTIONS OF THE
TWIN FORKS.
WINDS WILL BE SHIFTING TO THE NORTH LATE THIS AFTERNOON INTO THIS
EVENING...HOWEVER WITH A LONG ENOUGH PERIOD AND FETCH DOWN LONG
ISLAND SOUND ENOUGH WATER WILL BE PILED INTO THE WESTERN SOUND THAT
WILL NOT DRAIN BY THE TIME OF HIGH TIDE LATE THIS EVENING. ALL
FORECASTS SUPPORT THE THREAT OF MINOR TIDAL FLOODING WITH THE HIGH
TIDE...MARGINAL...SO WILL ISSUE AN ADVISORY.
ADDITIONALLY...MINOR TO MODERATE BEACH EROSION ISSUES ARE LIKELY
ALONG OCEAN BEACHES WITH 6 TO 9 FT BREAKING SURF AND AN EASTERLY
LONGSHORE CURRENT.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...COASTAL FLOOD ADVISORY FROM 9 PM THIS EVENING TO MIDNIGHT EDT
TONIGHT FOR CTZ009-010.
NY...COASTAL FLOOD ADVISORY FROM 9 PM THIS EVENING TO MIDNIGHT EDT
TONIGHT FOR NYZ071-073-078-176-177.
COASTAL FLOOD ADVISORY FROM 6 PM TO 10 PM EDT THIS EVENING FOR
NYZ075-178-179.
COASTAL FLOOD ADVISORY FROM 6 PM THIS EVENING TO 2 AM EDT
TUESDAY FOR NYZ079>081.
NJ...NONE.
MARINE...GALE WARNING UNTIL 2 AM EDT TUESDAY FOR ANZ330-335-338-340-345-
350-353-355.
&&
$$
AREA FORECAST DISCUSSION
NWS NEW YORK NY
959 AM EDT MON MAR 25 2013
.SYNOPSIS...
LOW PRESSURE INTENSIFYING SOUTH OF LONG ISLAND TODAY BRUSHES THE
REGION WITH WINTRY WEATHER. THE LOW TRACKS EAST TONIGHT ALLOWING
CANADIAN HIGH PRESSURE TO BUILD IN. THE HIGH WILL CONTROL OUR
WEATHER INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
MOST DIFFICULT FORECAST TO START THE WEEK. 993 HPA LOW EAST OF
THE DELMARVA AS OF 12 UTC WILL DEEPEN RAPIDLY THROUGH THE DAY.
HEAVY WET SNOW OVER CENTRAL AND SOUTHERN NJ HAS LOWERED TEMPS TO
FREEZING THERE.
LOCALLY...13 UTC TEMPS ARE NEAR 40 F WITH DEWS IN THE MID 20S. THIS
GIVES ME A WET BULB OF 34-35 F. PCPN IS HAVING A HARD TIME
MAKING NORTHWARD PROGRESS INTO THE DRY AIR.
TIME LAGGED RAPID REFRESH (RR) SUPPORTS HEAVIEST PCPN STAYING
JUST SOUTH OF THE REGION. SUBJECTIVELY...THIS TYPICALLY GETS
DISPLACED NW OF THE DEPICTED MODEL QPF. LATEST HRRR IS A BIT SOUTH
OF THE RR.
TEMPS ARE NEAR MAX AT THIS TIME AND WILL DROP TO WET BULB THIS
AFTN AS PCPN MOVES IN.
P-TYPE IS MAINLY WET SNOW...BUT WITH TEMPS ABOVE
FREEZING...ACCUMULATION IS DIFFICULT UNLESS HEAVIER PCPN MAKES IT
FURTHER NORTH THAN FORECAST.
HAVE CANCELED THE SNOW ADVISORY WITH THE BELIEF THAT EVEN IF WE
WERE TO REACH 3 INCHES...LIMITED IMPACT IS EXPECTED DUE TO TEMPS
ABOVE FREEZING.
&&
.SHORT TERM /TUESDAY/...
BY TUESDAY MORNING THE LOW WILL BE WELL EAST OF THE REGION WITH
PRECIPITATION HAVING ENDED. AN UPPER LOW...OR ELONGATED TROUGH WILL
REMAIN TO THE NORTH THAT ROTATES SOUTH DURING THE DAY. A RATHER
VIGOROUS VORT MAX ROTATES INTO THE REGION BY THE AFTERNOON. SO WILL
KEEP THE CHANCE OF FLURRIES ACROSS THE NORTHERN TIER...AND DRY
SOUTH. A CHILLY AIRMASS WILL REMAIN IN PLACE WITH A NORTHWEST FLOW
BEHIND THE LOW. LEANED TOWARD THE COOLER MET GUIDANCE FOR HIGHS WITH
A BLEND OF THE CURRENT FORECAST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
A LARGE AREA OF UPPER LEVEL LOW PRESSURE REMAINS JUST NORTH AND EAST
OF THE AREA THROUGH MUCH OF THE WEEK. A PERSISTENT NORTHWESTERLY
FLOW CONTINUES WITH PARTLY TO MOSTLY CLOUDY STRATO CU OVER THE AREA
THROUGH THE WEEKEND...MOSTLY WITH DAYTIME INSTABILITY. AS SHORTWAVES
ROTATE AROUND THIS LOW...CAN EXPECT FLURRIES/LIGHT SNOW INLAND AND
LIGHT RAIN SHOWERS...EVEN FLURRIES AT NIGHT...FARTHER EAST MANY
TIMES DURING THE WEEK. STRONGEST SHORTWAVES LOOK TO MOVE THROUGH
WEDNESDAY MORNING AND THURSDAY NIGHT. NOT CONFIDENT ENOUGH ON THE
TIMING TO WARRANT ANY MORE THAN SLIGHT CHANCE POPS. TEMPERATURES
WILL REMAIN IN THE UPPER 40S ON WEDNESDAY AND SLOWLY WARM BY THE
WEEKEND. LOWS REMAIN BELOW NORMAL...LOWER TO UPPER 30S THROUGH THE
WEEK.
THE UPPER LOW FINALLY PUSHES EAST OF THE AREA BY FRIDAY WITH A LARGE
AREA OF SURFACE HIGH PRESSURE PRESSING IN FROM THE WEST. SLIGHT
RIDING ALOFT WILL ALLOW TEMPERATURES TO WARM SLIGHTLY...TO NEAR
NORMAL VALUES. HIGHS WILL RANGE FROM THE UPPER 40S TO LOWER 50S WITH
HIGHS SUNDAY A DEGREE OR TWO WARMER. WINDS WILL BE LIGHT THROUGH THE
WEEKEND AND TURN SOUTHERLY SUNDAY NIGHT AHEAD OF A LOW PRESSURE
SYSTEM.
&&
.AVIATION /13Z MONDAY THROUGH FRIDAY/...
LOW PRES PASSES SOUTH OF LONG ISLAND TODAY.
VFR...LOWERING TO MVFR AS LIGHT SNOW OVERSPREADS KNYC TERMINALS
INITIALLY BY 15Z...AND THEN SNOW SPREADS TO THE NORTH AND EAST
THROUGHOUT THE MORNING. IFR CONDS WILL DEVELOP BY EARLY AFTERNOON
AND WILL CONTINUE THROUGH THE DAY WITH LOW CONFIDENCE IN LIFR DURING
THE AFTERNOON HOURS.
ACCUMULATING SNOW IS POSSIBLE ON RUNWAYS THROUGH THIS EVENING. 1-2
INCHES OF SNOW POSSIBLE AT KNYC METRO TERMINALS AND LONG
ISLAND...WITH AN INCH OR SO ELSEWHERE.
EAST TO NORTHEAST WINDS WILL INCREASE TO 15-20 KT WITH 25-35 KT
GUSTS ACROSS COASTAL TERMINALS AND 10-15 KT WITH 15-25 KT GUSTS
ACROSS THE INTERIOR LATER THIS MORNING. WINDS DIMINISH TO 10-15 KT
AFTER SUNSET AND WILL BACK TO THE NORTH.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN
BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: ONSET OF SNOWFALL MAY BE OFF BY +/- 1 HOUR.
WINDS MAY BRIEFLY GUST TO 35 KT IN THE AFTERNOON.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KJFK FCSTER COMMENTS: ONSET OF SNOWFALL MAY BE OFF BY +/- 1 HOUR.
WINDS MAY BRIEFLY GUST 35-40 KT IN THE AFTERNOON.
KLGA FCSTER COMMENTS: ONSET OF SNOWFALL MAY BE OFF BY +/- 1 HOUR.
WINDS MAY BRIEFLY GUST UP TO 35 KT IN THE AFTERNOON.
KTEB FCSTER COMMENTS: ONSET OF SNOWFALL MAY BE OFF BY +/- 1 HOUR.
WINDS MAY GUST TO 30 KT IN THE AFTERNOON.
KHPN FCSTER COMMENTS: ONSET OF SNOWFALL MAY BE OFF BY +/- 1 HOUR.
KISP FCSTER COMMENTS: ONSET OF SNOWFALL MAY BE OFF BY +/- 1 HOUR.
WINDS MAY BRIEFLY GUST TO 35 KT IN THE AFTERNOON.
.OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY...
.LATE MONDAY NIGHT...VFR.
.TUESDAY-WEDNESDAY..VFR.
.WEDNESDAY NIGHT...VFR WITH GUSTY NW WINDS POSSIBLE.
THURSDAY-FRIDAY...VFR.
&&
.MARINE...
WITH A DEEPENING LOW PRESSURE SYSTEM MOVING SOUTH AND EAST OF THE
WATERS TODAY AND TONIGHT WINDS AND GUSTS ARE EXPECTED TO INCREASE TO
GALE FORCE ON ALL THE FORECAST WATERS BY AROUND NOON TODAY. AS THE
STORM BEGINS TO TRACK EAST OF THE WATERS TONIGHT WINDS WILL DIMINISH
FROM WEST TO EAST...WITH WINDS BELOW GALE LATE THIS EVENING. THERE
IS SOME UNCERTAINTY AS TO HOW STRONG THE WINDS WILL BE IN LONG
ISLAND SOUND AND MAY PEAK JUST BELOW GALE FORCE. THE BEST AREA OF
GALE WINDS WILL BE ACROSS THE EASTERN SOUND AND PECONIC AND
GARDINERS BAYS. THERE WILL BE A FEW HOURS OF SMALL CRAFT GUSTS INTO
EARLY TUESDAY MORNING...THEN WINDS DIMINISH BELOW. SEAS ON THE OCEAN
WILL REMAIN AT OR ABOVE 5 FT INTO TUESDAY EVENING.
WINDS AND WAVES SUBSIDE BELOW SCA CRITERIA BY WEDNESDAY AS THE
SURFACE LOW CONTINUES TO MOVE EAST. MARGINAL SCA GUSTS ARE POSSIBLE
WEDNESDAY INTO THURSDAY AS THE PRESSURE GRADIENT TIGHTENS BETWEEN AN
OFFSHORE LOW AND APPROACHING HIGH PRESSURE. WINDS THEN SUBSIDE BELOW
SCA CRITERIA AND REMAIN THERE THROUGH THE WEEKEND.
&&
.HYDROLOGY...
LIQUID QPF OF AROUND A HALF INCH LIKELY FROM NORTHEASTERN NEW
JERSEY...ACROSS NYC...AND LONG ISLAND WITH JUST AROUND A TENTH
ACROSS THE NORTHERN TIER TODAY AND TONIGHT. THE PRECIPITATION WILL BE
IN THE FORM OF SNOW.
&&
.TIDES/COASTAL FLOODING...
MINOR COASTAL FLOODING EXPECTED DURING THE TIMES OF HIGH TIDE THIS
EVENING...FROM AROUND 7 PM TO MIDNIGHT...WITH SURGE OF AROUND 2 TO 2
1/2 FT. THE MAIN CONCERN IS ALONG THE SOUTH SHORE BAYS OF LONG
ISLAND...QUEENS...AND BROOKLYN AND PECONIC/GARDINERS BAYS. EASTERLY
SWELLS WILL LIKELY ENHANCE SURGE ALONG THE EASTERN PORTIONS OF THE
TWIN FORKS.
WINDS WILL BE SHIFTING TO THE NORTH LATE THIS AFTERNOON INTO THIS
EVENING...HOWEVER WITH A LONG ENOUGH PERIOD AND FETCH DOWN LONG
ISLAND SOUND ENOUGH WATER WILL BE PILED INTO THE WESTERN SOUND THAT
WILL NOT DRAIN BY THE TIME OF HIGH TIDE LATE THIS EVENING. ALL
FORECASTS SUPPORT THE THREAT OF MINOR TIDAL FLOODING WITH THE HIGH
TIDE...MARGINAL...SO WILL ISSUE AN ADVISORY.
ADDITIONALLY...MINOR TO MODERATE BEACH EROSION ISSUES ARE LIKELY
ALONG OCEAN BEACHES WITH 6 TO 9 FT BREAKING SURF AND AN EASTERLY
LONGSHORE CURRENT.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...COASTAL FLOOD ADVISORY FROM 9 PM THIS EVENING TO MIDNIGHT EDT
TONIGHT FOR CTZ009-010.
NY...COASTAL FLOOD ADVISORY FROM 9 PM THIS EVENING TO MIDNIGHT EDT
TONIGHT FOR NYZ071-073-078-176-177.
COASTAL FLOOD ADVISORY FROM 6 PM THIS EVENING TO 2 AM EDT
TUESDAY FOR NYZ079>081.
COASTAL FLOOD ADVISORY FROM 6 PM TO 10 PM EDT THIS EVENING FOR
NYZ075-178-179.
MARINE...GALE WARNING UNTIL 2 AM EDT TUESDAY FOR ANZ330-335-338-340-345-
350-353-355.
&&
$$
SYNOPSIS...NV
NEAR TERM...TONGUE
SHORT TERM...
LONG TERM...
AVIATION...MPS
MARINE...NV
HYDROLOGY...
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1123 AM EDT MON MAR 25 2013
.Forecast Update...
Issued at 1120 AM EDT Mon Mar 25 2013
Snow showers continue across the region late this morning. Under the
heavier bands we are seeing some reduced visibilities and light
accumulations. The accumulations are mainly on grassy surfaces,
though some roads may be affected while the snow is falling.
However, temperatures remain at or just above freezing across the
region. Pops were increased across south central Kentucky for this
afternoon with this update. Mesoscale models indicate bands will
continue to form in this area through the afternoon hours. For now
will leave the Special Weather Statement and Winter Weather Advisory
as is and continue to monitor conditions early this afternoon.
&&
.Short Term (Now - Tuesday)...
Issued at 305 AM EDT Mon Mar 25 2013
The roller-coaster of weather continues this morning. Mother Nature
has shown her full hand to the Ohio Valley over the past 24 hours
with severe thunderstorms, strong winds, heavy rain, and now wintry
precipitation.
The potent upper level disturbance and associated surface low
continue to push off to the northeast. In its wake, strong
westerly winds have enveloped the region, allowing much cooler air
to filter in. The strong band of mid-level frontogenesis associated
with the TROWAL continues to pivot southeast across Indiana and
Illinois. However, this feature is forecast to continue to weaken
as the system becomes a bit more vertically stacked and the surface
low quickly fills in , which is evident by decreasing reflectivities
over the past several hours. However, there still may be a brief
window for some very light accumulations this morning mainly across
southern Indiana and north central Kentucky. With surface
temperatures hovering near freezing and road temperatures in the
upper 30s, do not expect this snowfall to be heavy enough to
accumulate on roadways through the morning hours.
Attention then turns toward late this morning and early this
afternoon, as another upper-level trough axis swings through the
state. As the cold core of the system moves overhead, lapse rates
will steepen substantially this afternoon. Guidance differs
slightly in how the low-level thermal profile will look (with the
05Z RAP showing dry adiabatic lapse rates up to 800mb!), but all are
showing rather impressive low-level instability. With the steep
lapse rates, ELs look to top out around -15C, which would promote
dendritic snow growth. Therefore, think that moderate to locally
heavy snow showers are a good bet today, especially from Louisville
east into the northern Bluegrass.
The age old question then becomes, what will the impact of these
snow showers be. With surface temperatures rising into the middle
30s, much of the snow will be lost to melting. Additionally, road
temperatures will remain rather warm. That being said, the isolated
heavy showers may have the rates to overcome the warmer ground/roads
and cause quick accumulations only to melt soon after the heaviest
precipitation moves out. Additionally, strong westerly winds
combined with the blowing snow will create poor visibilities in the
stronger showers. Therefore, believe there still could be some
impacts from these, even though amounts at any one location are
unlikely to exceed an inch at any one time. For these reasons, will
go ahead and leave the Winter Weather Advisory as is.
The snow showers will linger into the overnight hours into Tuesday
morning, although the intensity should begin to wane. By Tuesday
afternoon, the bulk of the snow showers should push east of the
area. With the expected cloud cover and brisk westerly winds today
and tomorrow, have continued to undercut guidance for highs.
.Long Term (Tuesday Night - Sunday)...
Issued at 300 AM EDT Mon Mar 25 2013
A period of benign weather is in store for the rest of the work week
and into the weekend. High pressure will build eastward from the
Mississippi River valley Wednesday. Models are consistent now in
less of a rain chance with any warm front oriented northwest to
southeast in our vicinity. The best chance...only slight for this
forecast package...looks to be over the southwest forecast area
Friday and Saturday. Then on Sunday the GFS has a cold front close
enough to cause some rains. 12Z Euro and new Euro coming in are not
as quick with this front, so have undercut AllBlend pops a little to
lean more towards the Euro solutions.
Temperatures should fall into the 20s both Wednesday and Thursday
mornings, with daytime highs around 40 Wednesday then increasing to
the 45-50 degree range Thursday. The warmup will continue into the
weekend, with highs by then in the mid to upper 50s, still below
normal for late March, but likely a welcome change for the Easter
weekend.
&&
.Aviation (12Z TAF Issuance)...
Issued at 710 AM EDT Mon Mar 25 2013
A deep area of low pressure will continue to lift slowly northeast
into Ohio this morning. In the wake of this low, cold air and
scattered snow showers will continue to filter into the Ohio
Valley. These snow showers will be scattered in nature, quickly
dropping ceilings/visibilities for a brief time only to quickly
improve once the shower rolls through. Therefore, the best way to
handle these showers is with a TEMPO group through the first 4
hours. The showers should become a bit more widespread after 16Z
across KSDF and KLEX, so will go prevailing IFR for reduced
visibilities after 16Z.
The other concern tonight will be winds. Observations continue to
show winds gusting up around 25 knots which will continue throughout
the the day today, before the gusts die down and winds slowly
decrease this evening. Snow showers should wane in coverage and
intensity after sunset this evening, but will continue through at
least the morning hours on Tuesday.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING
FOR INZ076>079-083-084-089>092.
KY...WINTER WEATHER ADVISORY UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING
FOR KYZ023>025-028>043-045-048-049.
$$
Update...........EER
Short Term.......KD
Long Term........RJS
Aviation.........KD
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
712 AM EDT MON MAR 25 2013
...Updated Aviation Discussion...
.Short Term (Now - Tuesday)...
Issued at 305 AM EDT Mon Mar 25 2013
The roller-coaster of weather continues this morning. Mother Nature
has shown her full hand to the Ohio Valley over the past 24 hours
with severe thunderstorms, strong winds, heavy rain, and now wintry
precipitation.
The potent upper level disturbance and associated surface low
continue to push off to the northeast. In its wake, strong
westerly winds have enveloped the region, allowing much cooler air
to filter in. The strong band of mid-level frontogenesis associated
with the TROWAL continues to pivot southeast across Indiana and
Illinois. However, this feature is forecast to continue to weaken
as the system becomes a bit more vertically stacked and the surface
low quickly fills in , which is evident by decreasing reflectivities
over the past several hours. However, there still may be a brief
window for some very light accumulations this morning mainly across
southern Indiana and north central Kentucky. With surface
temperatures hovering near freezing and road temperatures in the
upper 30s, do not expect this snowfall to be heavy enough to
accumulate on roadways through the morning hours.
Attention then turns toward late this morning and early this
afternoon, as another upper-level trough axis swings through the
state. As the cold core of the system moves overhead, lapse rates
will steepen substantially this afternoon. Guidance differs
slightly in how the low-level thermal profile will look (with the
05Z RAP showing dry adiabatic lapse rates up to 800mb!), but all are
showing rather impressive low-level instability. With the steep
lapse rates, ELs look to top out around -15C, which would promote
dendritic snow growth. Therefore, think that moderate to locally
heavy snow showers are a good bet today, especially from Louisville
east into the northern Bluegrass.
The age old question then becomes, what will the impact of these
snow showers be. With surface temperatures rising into the middle
30s, much of the snow will be lost to melting. Additionally, road
temperatures will remain rather warm. That being said, the isolated
heavy showers may have the rates to overcome the warmer ground/roads
and cause quick accumulations only to melt soon after the heaviest
precipitation moves out. Additionally, strong westerly winds
combined with the blowing snow will create poor visibilities in the
stronger showers. Therefore, believe there still could be some
impacts from these, even though amounts at any one location are
unlikely to exceed an inch at any one time. For these reasons, will
go ahead and leave the Winter Weather Advisory as is.
The snow showers will linger into the overnight hours into Tuesday
morning, although the intensity should begin to wane. By Tuesday
afternoon, the bulk of the snow showers should push east of the
area. With the expected cloud cover and brisk westerly winds today
and tomorrow, have continued to undercut guidance for highs.
.Long Term (Tuesday Night - Sunday)...
Issued at 300 AM EDT Mon Mar 25 2013
A period of benign weather is in store for the rest of the work week
and into the weekend. High pressure will build eastward from the
Mississippi River valley Wednesday. Models are consistent now in
less of a rain chance with any warm front oriented northwest to
southeast in our vicinity. The best chance...only slight for this
forecast package...looks to be over the southwest forecast area
Friday and Saturday. Then on Sunday the GFS has a cold front close
enough to cause some rains. 12Z Euro and new Euro coming in are not
as quick with this front, so have undercut AllBlend pops a little to
lean more towards the Euro solutions.
Temperatures should fall into the 20s both Wednesday and Thursday
mornings, with daytime highs around 40 Wednesday then increasing to
the 45-50 degree range Thursday. The warmup will continue into the
weekend, with highs by then in the mid to upper 50s, still below
normal for late March, but likely a welcome change for the Easter
weekend.
&&
.Aviation (12Z TAF Issuance)...
Issued at 710 AM EDT Mon Mar 25 2013
A deep area of low pressure will continue to lift slowly northeast
into Ohio this morning. In the wake of this low, cold air and
scattered snow showers will continue to filter into the Ohio
Valley. These snow showers will be scattered in nature, quickly
dropping ceilings/visibilities for a brief time only to quickly
improve once the shower rolls through. Therefore, the best way to
handle these showers is with a TEMPO group through the first 4
hours. The showers should become a bit more widespread after 16Z
across KSDF and KLEX, so will go prevailing IFR for reduced
visibilities after 16Z.
The other concern tonight will be winds. Observations continue to
show winds gusting up around 25 knots which will continue throughout
the the day today, before the gusts die down and winds slowly
decrease this evening. Snow showers should wane in coverage and
intensity after sunset this evening, but will continue through at
least the morning hours on Tuesday.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING
FOR INZ076>079-083-084-089>092.
KY...WINTER WEATHER ADVISORY UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING
FOR KYZ023>025-028>043-045-048-049.
$$
Short Term.......KD
Long Term........RJS
Aviation.........KD
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
745 AM EDT MON MAR 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 509 AM EDT MON MAR 25 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WEAK MID/UPPER LEVEL NE FLOW
THROUGH THE NRN GREAT LAKES BETWEEN AND LOW OVER THE OHIO VALLEY AND
A RIDGE OVER HUDSON BAY. AT THE SFC...NE WINDS ALSO PREVAILED ACROSS
THE REGION BETWEEN LOW PRESSURE OVER SRN OHIO AND A RIDGE FROM
SASK/MANITOBA INTO THE PLAINS. MARGINAL OVER LAKE INSTABILITY WITH
850 MB TEMPS AROUND -10C ONLY SUPPORTED PATCHY LIGHT SNOW OR
FLURRIES INTO N CNTRL UPPER MI AIDED BY UPSLOPE FLOW (25-30 KT
950-900 MB WINDS) INTO THE HIGHER TERRAIN. UPSTREAM...PERIODS OF -FZDZ
WERE OBSERVED AT CYYU AND CYGQ DURING PERIODS WHERE SATELLITE
IMAGERY SUGGESTED MOISTURE WAS MORE SHALLOW.
AS THE NEXT BATCH OF 925-750 MB MOISTURE MOISTURE MOVES INTO THE
REGION...THE POTENTIAL FOR LIGHT PCPN WILL INCREASE AND CONTINUE
INTO TONIGHT. WITH 850 MB TEMPS AND MIN TEMPS IN THE MOIST LAYER
AROUND -10C...AND THE STRONGEST UPWARD MOTION BELOW THE DGZ...MAINLY
JUST SMALL SNOWFLAKES OR EVEN ICE PELLETS ARE EXPECTED WITH A LOW
SNOW/WATER RATIO. ANY ACCUMULATIONS SHOULD AMOUNT TO AN INCH OR LESS.
GIVEN THE UPSTREAM OBS AND TRENDS FROM THE LAST SEVERAL DAYS...SOME
PATCHY -FZDZ ALSO MAY MIX WITH THE -SHSN/FLURRIES THIS MORNING
BEFORE THE DEEPER MOISTURE BECOMES ESTABLISHED.
AS THE MOIST LAYER BECOMES MORE SHALLOW LATE TONIGHT OVER NCNTRL AND
TEMPS MODERATE TO NEAR -10C AT THE TOP OF MOIST LAYER PER MODEL
SNDGS...-FZDZ WILL AGAIN BE POSSIBLE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 435 AM EDT MON MAR 25 2013
UPPER MICHIGAN WILL REMAIN UNDER THE INFLUENCE OF THE LINGERING
SFC-500MB TROUGH ON TUESDAY. IT WILL BE PUSHED EASTWARD THROUGH MID
WEEK AS THE 500MB HIGH OVER HUDSON BAY SINKS SOUTH INTO THE REGION.
SLOWLY WARMING HIGH TEMPERATURES THROUGH THE PERIOD...WITH ALL AREAS
/OR NEARLY ALL AREAS/ PUSHING ABOVE FREEZING FROM WEDNESDAY ON...AND
INTO THE LOW 40S FOR THE WEEKEND. DRY WEATHER SHOULD BE THE RULE
WEDNESDAY AFTERNOON THROUGH FRIDAY NIGHT AS THE SFC HIGH TO OUR WEST
CENTERS ITSELF ACROSS THE REGION. LOOK FOR SLOWLY DIMINISHING
UPSLOPE CHANCES OF LIGHT SNOW SHOWERS WITH THE SHALLOW MOISTURE AT
OR BELOW 800MB AND DEEPENING INVERSION HEIGHTS. THE NEXT ROUND OF
PRECIPITATION LOOKS TO BE ASSOCIATED WITH THE 500MB LOW OVER HUDSON
BAY SATURDAY SWINGING A SIZABLE TROUGH ACROSS THE NORTHERN PLAINS
THROUGH THE UPPER GREAT LAKES THROUGH THE WEEKEND. THE SFC HIGH WILL
BE SHIFTED SOUTHEAST...AND A COLD FRONT WILL LIKELY SWING ACROSS
WESTERN LAKE SUPERIOR LATE SATURDAY...AND SLOWLY SLIDE EAST OF LAKE
SUPERIOR/UPPER MI SUNDAY BY LATE AFTERNOON. THE 25/00Z ECMWF LOOKS
TO BE A BIT DEEPER AND SLOWER WITH THE PASSAGE OF THE COLD FRONT.
THE 25/00Z GFS KEEP MUCH OF THE ENERGY TO OUR SOUTH...AND AS A
RESULT MUCH OF THE PRECIPITATION. STILL COULD GET AROUND 0.05-0.2IN
OF LIQUID OUT OF THE FRONTAL PASSAGE.
TEMPERATURES FOR THE FIRST HALF OF THE WEEKEND WERE WARMED
SLIGHTLY...WITH A CONTINUED NEED FOR MIXED PRECIPITATION AS HIGH
TEMPERATURES HOVER AROUND 40F. WAA WILL RESULT IN 850MB TEMPS RISING
FROM AROUND -7C AT 12Z FRIDAY TO A CWA AVERAGED -1.5C BY 00Z
SUNDAY...AND POSSIBLY UP TO 0C NEAR MENOMINEE AT 06Z SUNDAY. WAS A
BIT HESITANT TO JUST HAVE RAIN IN THE FORECAST FOR SATURDAY
NIGHT...GIVEN THE TIME OF DAY AND THE FACT THAT IT WAS DAY 5-6...BUT
WITH LOWS NEAR 32F ALL RAIN WOULD BE A SERIOUS POSSIBILITY. LATER
SHIFTS WILL HAVE PLENTY OF TIME TO REDEFINE THE COVERAGE AREA OF
BOTH RAIN AND SNOW FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 743 AM EDT MON MAR 25 2013
AS MOIST AIR MOVES IN FROM THE NORTHEAST...MVFR CIGS WILL PREVAIL.
SOME -SHSN/-FZDZ IS ALSO EXPECTED...ESPECIALLY AT IWD/SAW WHERE THE
FLOW PRESENTS A BETTER UPSLOPE WIND COMPONENT. ALTHOUGH DAYTIME
HEATING AFTERNOON MIGHT RESULT IN SOME IMPROVEMEN THIS
AFTERNOON...DEEPER MOISTURE THAN ON SUNDAY SHOULD MAINTAIN THE MVFR
CIGS. THE ARRIVAL OF EVEN DEEPER MOISTURE TONIGHT IN THE PRESENCE OF
DIURNAL COOLING AND CYCLONIC NNE FLOW THAT FAVORS LK EFFECT/ENHANCED
PCPN SUGGESTS MORE -SHSN/MVFR CIGS WILL LINGER.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 509 AM EDT MON MAR 25 2013
HIGH PRESSURE IN PLACE OVER THE NORTHERN PLAINS AND LOW PRESSURE
MOVING EASTWARD ACROSS THE TENNESSEE VALLEY WILL LEAD TO A TIGHT
PRESSURE GRADIENT OVER LAKE SUPERIOR THROUGH TUESDAY. THIS WILL
RESULT IN NORTHERLY WINDS 15 TO 25 KNOTS. FOR TUESDAY AFTERNOON AND
BEYOND...HIGH PRESSURE WILL SPRAWL ACROSS THE GREAT LAKES...KEEPING
WINDS BELOW 20 KNOTS OUT OF THE NORTH AND WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
308 PM MDT MON MAR 25 2013
.SHORT TERM...RIDGE BUILDING OVER WESTERN COLORADO WITH NORTHWEST
FLOW ACROSS CFWA. AIRMASS DRIER WITH WARM AIR ADVECTION OVER AREA.
WEB CAMS ACROSS MOUNTAINS HAVE SHOWN LINGERING SNOW SHOWERS HAVE
DISSIPATED. LATEST RAP CONTINUES TO INDICATE SOME LIGHT PRECIP
OVER PARK AND SUMMIT COUNTIES THROUGH 03Z. THIS SEEMS OVERDONE
GIVEN LATEST TRENDS. RIDGE WILL CONTINUE TO BUILD ACROSS COLORADO
TONIGHT WITH INCREASING HIGH LEVEL MOISTURE. TEMPERATURES TO BE A
FEW DEGREES WARMER THAN THIS MORNING`S READINGS. LATEST SYNTHETIC
SATELLITE LOOPS SHOWING SOME DEVELOPMENT OF A WAVE CLOUD ALONG
FOOTHILLS AFTER MIDNIGHT. WILL ADD A BIT MORE CLOUD TO THE GRIDS.
ON TUESDAY...FLOW ALOFT BECOMES A BIT MORE WESTERLY DURING THE
MORNING AS UPPER LEVEL DISTURBANCE MOVES INTO THE NORTHERN GREAT
BASIN. CROSS SECTIONS SHOW MOISTURE INCREASING ACROSS MOUNTAINS
ALONG WITH SOME INCREASE IN MID LEVEL QG ASCENT. LATEST MODELS
BEGIN BRINGING SOME LIGHT QPF AND SNOW ACCUMULATIONS TO THE
MOUNTAINS BY THE AFTERNOON. WILL INCLUDE SOME LOW POPS AFTER 15Z
ACROSS ZONE 31 AND WESTERN EDGE OF ZONE 34 IN SUMMIT COUNTY.
DURING THE AFTERNOON...MOISTURE AND INSTABILITY CONTINUES TO
INCREASE OVER THE MOUNTAINS. LATEST QG VERTICAL VELOCITY PROGS
SHOWS THE GREATEST LIFT OVER WESTERN UTAH. STILL SUFFICIENT LIFT
ALONG WITH LAPSE RATES AROUND 7 C/KG ENOUGH FOR A GOOD CHANCE OF
SNOW SHOWERS OVER THE HIGH COUNTRY. WILL KEEP ACCUMULATIONS LIGHT.
ALSO A CHANCE FOR RAIN AND SNOW SHOWERS ACROSS NORTH AND MIDDLE
PARKS. DOWNSLOPE FLOW ACROSS FOOTHILLS AND SOUTH PARK WILL HINDER
PRECIP CHANCES AND WILL CONTINUE THE SLIGHT CHANCE THERE. AS FOR
PLAINS...SOME INCREASE IN MID AND HIGH LEVEL MOISTURE THROUGH THE
DAY. LATEST GFS INDICATING SOME SHOWERS COULD MOVE ONTO URBAN
CORRIDOR LATE AFTERNOON...OTHER MODELS KEEP THINGS DRY. WILL
EXCLUDE THE SHOWERS AT THIS TIME. TEMPERATURE AND THICKNESS PROGS
SHOW HIGHS MODERATING SLIGHTLY...BUT CLOUDS AND SNOW COVER WILL
KEEP TEMPERATURES BELOW SEASONAL NORMALS.
.LONG TERM...WEST-NORTHWESTERLY FLOW ALOFT IS PROGGED TUESDAY NIGHT
FOR THE CWA ALONG WITH A WEAK UPPER TROUGH TO MOVE ACROSS. AFTER
THAT...UPPER RIDGING IS OVER COLORADO WITH WEAKER ZONAL FLOW OVER
THE CWA WEDNESDAY THROUGH THURSDAY NIGHT. THERE IS WEAK UPWARD
VERTICAL VELOCITY PROGGED TUESDAY NIGHT...THEN BENIGN SYNOPTIC
SCALE ENERGY IS PROGGED THROUGH THURSDAY NIGHT. THERE IS A BIT OF
UPSLOPE PROGGED IN THE BOUNDARY LAYER FLOW FOR THE PLAINS AND
FOOTHILLS TUESDAY NIGHT INTO WEDNESDAY. AFTER THAT FAIRLY WEAK
NORMAL DUIRNAL PATTERNS ARE PROGGED. FOR MOISTURE...THERE IS
PRETTY DECENT ALPINE MOISTURE TUESDAY NIGHT WITH THE WEAK TROUGH.
THERE IS SOME IN THE MID AND UPPER LEVELS OVER ALL OF THE CWA
WEDNESDAY THROUGH THURSDAY NIGHT. THE QPF FIELDS HAVE LIMITED
MEASURABLE PRECIPITATION MAINLY OVER THE MOUNTAINS TUESDAY NIGHT.
THERE IS A TINY BIT INDICATED ON WEDNESDAY INTO WEDNESDAY
EVENING. THERE IS ACTUALLY A BIT OF CAPE OVER THE MOUNTIANS
...FOOTHILLS AND WESTERN PLAINS WEDNESDAY AFTERNOON. VALUES ARE UP
TO 250 J/KG. WILL LEAVE IN OR GO WITH 30-60% POPS IN THE MOUNTAINSTUESDAY
NIGHT INTO WEDNESDAY...HIGHER POPS TUESDAY NIGHT. THERE IS
MOISTURE...A BIT OF OROGRAPHIC HELP...SOME SYNOPTIC SCALE ENERGY
AND FAIRLY STEEP LAPSE RATES. WEDNESDAY NIGHT AND THURSDAY LOOK
DRY. FOR TEMPERATURES...WEDNESDAY`S HIGHS ARE 1-4 C WARMER THAN
TUESDAY`S. THURSDAY`S HIGHS ARE 1-4 C WARMER THAN WEDNESDAY`S.
WILL CONTINUE THE TREND OF LOWER READINGS OVERALL AND SEE WHAT THE
SNOW FIELD OVER THE PLAINS DOES. FOR THE LATER DAYS...FRIDAY
THROUGH MONDAY...MODELS KEEP AN UPPER RIDGE AXIS JUST WEST OF
COLORADO FRIDAY AND SATURDAY. THE FLOW ALOFT IS WEST OR
NORTHWESTERLY AND PRETTY WEAK THOSE TWO DAYS. ON SUNDAY...THE
UPPER RIDGE AXIS IS PROGGED TO PUSH EASTWARD ACROSS COLORADO. BOTH
THE ECMWF AND GFS SHOW A CLOSED LOW OVER THE GREAT BASIN/DESERT
SOUTHWEST UNITED STATES BY MONDAY AFTERNOON. THERE IS QUITE A BIT
OF MOISTURE AROUND FRIDAY AND SATURDAY...THEN AGAIN MONDAY.
TEMPERATURES LOOK PRETTY MILD ALL FOUR DAYS.
&&
.AVIATION...LIGHT SOUTHEAST WINDS CURRENTLY ACROSS AREA AIRPORTS.
LATEST RAP AND HRRR CONTINUE TO SHOW LIGHT SOUTHEASTERLIES
CONTINUING INTO THE EVENING...THEN BECOMING SOUTHWEST AROUND 03Z
AS DRAINAGE FLOW DEVELOPS. SOME INCREASE IN HIGH LEVEL MOISTURE
AFTER MIDNIGHT WITH POTENTIAL FOR WAVE CLOUD DEVELOPING ALONG
FOOTHILLS BETWEEN 09Z AND 15Z. CEILINGS TO REMAIN ABOVE 12000
FEET AGL. VFR TO PREVAIL. ON TUESDAY...LIGHT SOUTHWEST WINDS TO
SHIFT TO THE SOUTHEAST AROUND 18Z WITH INCREASING MID AND HIGH
LEVEL CLOUDS. NO PRECIP EXPECTED WITH VFR CONTINUING. CEILINGS
AROUND 10000 FEET AGL EXPECTED THROUGH THE AFTERNOON.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1246 PM EDT MON MAR 25 2013
...Updated Aviation Discussion...
.Forecast Update...
Issued at 1120 AM EDT Mon Mar 25 2013
Snow showers continue across the region late this morning. Under the
heavier bands we are seeing some reduced visibilities and light
accumulations. The accumulations are mainly on grassy surfaces,
though some roads may be affected while the snow is falling.
However, temperatures remain at or just above freezing across the
region. Pops were increased across south central Kentucky for this
afternoon with this update. Mesoscale models indicate bands will
continue to form in this area through the afternoon hours. For now
will leave the Special Weather Statement and Winter Weather Advisory
as is and continue to monitor conditions early this afternoon.
&&
.Short Term (Now - Tuesday)...
Issued at 305 AM EDT Mon Mar 25 2013
The roller-coaster of weather continues this morning. Mother Nature
has shown her full hand to the Ohio Valley over the past 24 hours
with severe thunderstorms, strong winds, heavy rain, and now wintry
precipitation.
The potent upper level disturbance and associated surface low
continue to push off to the northeast. In its wake, strong
westerly winds have enveloped the region, allowing much cooler air
to filter in. The strong band of mid-level frontogenesis associated
with the TROWAL continues to pivot southeast across Indiana and
Illinois. However, this feature is forecast to continue to weaken
as the system becomes a bit more vertically stacked and the surface
low quickly fills in , which is evident by decreasing reflectivities
over the past several hours. However, there still may be a brief
window for some very light accumulations this morning mainly across
southern Indiana and north central Kentucky. With surface
temperatures hovering near freezing and road temperatures in the
upper 30s, do not expect this snowfall to be heavy enough to
accumulate on roadways through the morning hours.
Attention then turns toward late this morning and early this
afternoon, as another upper-level trough axis swings through the
state. As the cold core of the system moves overhead, lapse rates
will steepen substantially this afternoon. Guidance differs
slightly in how the low-level thermal profile will look (with the
05Z RAP showing dry adiabatic lapse rates up to 800mb!), but all are
showing rather impressive low-level instability. With the steep
lapse rates, ELs look to top out around -15C, which would promote
dendritic snow growth. Therefore, think that moderate to locally
heavy snow showers are a good bet today, especially from Louisville
east into the northern Bluegrass.
The age old question then becomes, what will the impact of these
snow showers be. With surface temperatures rising into the middle
30s, much of the snow will be lost to melting. Additionally, road
temperatures will remain rather warm. That being said, the isolated
heavy showers may have the rates to overcome the warmer ground/roads
and cause quick accumulations only to melt soon after the heaviest
precipitation moves out. Additionally, strong westerly winds
combined with the blowing snow will create poor visibilities in the
stronger showers. Therefore, believe there still could be some
impacts from these, even though amounts at any one location are
unlikely to exceed an inch at any one time. For these reasons, will
go ahead and leave the Winter Weather Advisory as is.
The snow showers will linger into the overnight hours into Tuesday
morning, although the intensity should begin to wane. By Tuesday
afternoon, the bulk of the snow showers should push east of the
area. With the expected cloud cover and brisk westerly winds today
and tomorrow, have continued to undercut guidance for highs.
.Long Term (Tuesday Night - Sunday)...
Issued at 300 AM EDT Mon Mar 25 2013
A period of benign weather is in store for the rest of the work week
and into the weekend. High pressure will build eastward from the
Mississippi River valley Wednesday. Models are consistent now in
less of a rain chance with any warm front oriented northwest to
southeast in our vicinity. The best chance...only slight for this
forecast package...looks to be over the southwest forecast area
Friday and Saturday. Then on Sunday the GFS has a cold front close
enough to cause some rains. 12Z Euro and new Euro coming in are not
as quick with this front, so have undercut AllBlend pops a little to
lean more towards the Euro solutions.
Temperatures should fall into the 20s both Wednesday and Thursday
mornings, with daytime highs around 40 Wednesday then increasing to
the 45-50 degree range Thursday. The warmup will continue into the
weekend, with highs by then in the mid to upper 50s, still below
normal for late March, but likely a welcome change for the Easter
weekend.
&&
.Aviation (18Z TAF Issuance)...
Issued at 1245 PM EDT Mon Mar 25 2013
Snow showers will continue this afternoon and into the overnight
hours as an upper level disturbance crosses the Ohio Valley.
Visibilities will generally be in the 2-3 mile range, except in the
the few heavier snow showers that may develop this afternoon. Winds
will remain breezy from the WNW through the afternoon hours with
gusts generally around 20 knots, though they may be as high as 25
knots at times. Ceilings will generally remain MVFR.
Snow showers will become lighter and eventually end overnight.
Ceilings are expected to improve by mid morning to early afternoon
tomorrow. Gusts will lessen tonight as the pressure gradient across
the region relaxes. Though a few snow showers are expected tomorrow,
they will be much less widespread than today, so will keep mention
of this out of the TAFs for now.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...WINTER WEATHER ADVISORY UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING
FOR INZ076>079-083-084-089>092.
KY...WINTER WEATHER ADVISORY UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING
FOR KYZ023>025-028>043-045-048-049.
$$
Update...........EER
Short Term.......KD
Long Term........RJS
Aviation.........EER
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
357 PM EDT MON MAR 25 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 356 PM EDT MON MAR 25 2013
...CHALLENGING FORECAST IN STORE THIS AFTERNOON THROUGH TUESDAY...
BROAD CYCLONIC FLOW IS PROGGED TO LINGER OVER MUCH OF THE GREAT
LAKES REGION THIS AFTERNOON THROUGH MUCH OF THE DAY TUESDAY AS A LOW
PRESSURE SYSTEM SLOWLY SHIFTS FROM THE OHIO VALLEY THIS
NORTHEASTWARD TOWARD THE NEW ENGLAND AREA. RADAR IS SHOWING SEVERAL
RETURNS NEAR LAKE SUPERIOR. SURFACE OBSERVATIONS AND WEBCAMS
INDICATE THAT THIS PRECIPITATION IS A MIX OF LIGHT FREEZING RAIN AS
WELL AS LIGHT SNOW SHOWERS. THE MAIN ISSUE FOR THE DAY INTO THE
NIGHT WILL BE PRECIPITATION TYPE AS SOUNDINGS SHOW ONLY MARGINAL
SUPPORT FOR SNOW DEVELOPMENT WITH THE TOP OF THE MOIST LAYER
REACHING AROUND -10C THROUGH MID MORNING. RUC AND NAM SOUNDING
INDICATE SLIGHTLY COOLER AIR...AROUND 12C...MOVING IN NEAR THE TOP
OF THE MOIST LAYER DURING THE AFTERNOON HOURS. THIS MAY TRANSITION
THE FZDZ OVER TO MORE OF A LIGHT SNOW AND FZDZ MIX OR TRANSITION
OVER TO ALL SNOW. AROUND 00Z SOUNDINGS WARM SLIGHTLY ALOFT AHEAD OF
THE NEXT 500MB TROUGH ROTATING INTO THE AREA. THIS WILL ALLOW THE
PRECIPITATION TO TRANSITION BACK TO A -FZDZ/-SHSN MIX...WHICH WILL
LAST THROUGH MID AFTERNOON BEFORE SLOWLY TAPERING OFF. CONFIDENCE
LEVEL IN ANY ONE TYPE OF PRECIPITATION IS LOW AS TEMPS ALOFT ARE
HUGGING THE -12C ISOTHERM WHICH IS WHERE ICE IS INTRODUCED INTO THE
CLOUD...THEREFORE HAVE KEPT A MIX OF FZDZ AND -SHSN IN THE FORECAST.
DELTA T VALUES ARE EXPECTED TO BE AROUND -12 TO -14 ALONG WITH MOIST
LOW LEVEL PROFILES WHICH WILL CONTINUE TO SUPPORT LAKE EFFECT
PRECIPITATION...WHICH MAY BE ENHANCED FURTHER OVERNIGHT AS THE
TROUGH PASSES DIRECTLY OVERHEAD. THERE IS ALSO AN UPSLOPE COMPONENT
WHICH MAY HELP FOCUS THE PRECIPITATION OVER THE HIGHER
TERRAIN...ESPECIALLY IN NORTH CENTRAL LOCATIONS AS WELL AS OVER THE
KEWEENAW.
TUESDAY...LAKE EFFECT SHSN AND FZDZ WILL LIKELY LINGER THROUGH THE
MID TO LATE MORNING HOURS BEFORE THE 500MB TROUGH SHIFTS TO THE
SOUTH OF THE UPPER PENINSULA. THIS WILL ALLOW SURFACE TO 850 DELTA T
VALUES TO BE AROUND -8C TO -9C...EFFECTIVELY REDUCING THE LAKE
EFFECT PRECIPITATION. SCATTERED FZDZ MAY LINGER OVER THE HIGH
TERRAIN IN CENTRAL UPPER MI AS A SIGNIFICANT AMOUNT OF LOW LEVEL
MOISTURE REMAINS IN PLACE AND UPSLOPE NORTH TO NORTH-NORTHWEST FLOW
CONTINUES TO MOVE FROM LAKE SUPERIOR INLAND.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 356 PM EDT MON MAR 25 2013
UPPER TROUGH THAT HAS BEEN INFLUENCING THE AREA OVER THE LAST
SEVERAL DAYS WILL BEGIN TO SHIFT EAST TUESDAY NIGHT INTO
WEDNESDAY...ALLOWING A WEAK UPPER RIDGE AND SURFACE HIGH PRESSURE TO
MOVE IN WEDNESDAY NIGHT AND REMAIN THROUGH FRIDAY.
LINGERING MOISTURE UNDER THE CYCLONIC FLOW FROM THE UPPER AND
SURFACE LOW OF THE NEW ENGLAND STATES WILL CONTINUE TO BRING THE
POTENTIAL FOR CLOUDS AND PRECIPITATION FOR TUESDAY NIGHT AND
WEDNESDAY. THIS WILL BE ESPECIALLY TRUE FOR LOCATIONS FAVORED BY
NORTH TO NORTHWEST WINDS. MODELS ARE FAIRLY PERSISTENT ON THE LOWER
LEVEL MOISTURE...925-850MB...BEING PRESENT FOR TUESDAY NIGHT INTO
WEDNESDAY MORNING WHILE A SURFACE TROUGH DROPS SOUTH ACROSS EASTERN
LAKE SUPERIOR. BEST CHANCES FOR PRECIPITATION LOOK TO BE ON TUESDAY
NIGHT INTO WEDNESDAY MORNING...BEFORE THE DEEPER MOISTURE DEPARTS
AND SUBSIDENCE FROM THE APPROACHING HIGH BEGINS TO INFLUENCE THE
CLOUD THICKNESS. WILL CONTINUE TO MENTION SLIGHT CHANCE AND A FEW
LOCALIZED CHANCE POPS FOR THE FAVORED NORTH-NORTHWEST LOCATIONS.
TYPE LOOKS TO BE A CONCERN AGAIN ON TUESDAY NIGHT INTO
WEDNESDAY...WITH CLOUD TOP TEMPERATURES BARELY RISING ABOVE -10C. AS
HAS BEEN THE CASE OVER THE LAST COUPLE OF DAYS...THE LIGHTER SHOWERS
WILL LIKELY BE FZDZ AND IF ANY STRONGER SHOWERS OCCUR THERE COULD BE
SNOW ASSOCIATED WITH IT. WILL LIMIT THE SNOW MENTION THOUGH...AS
CLOUD TOPS APPEAR TO BE A COUPLE DEGREES WARMER THAN THE LAST COUPLE
OF DAYS.
WEDNESDAY NIGHT INTO THURSDAY WILL BE THE TRANSITION PERIOD...AS THE
HIGH PRESSURE RIDGE MOVES OVER THE AREA FROM THE UPPER MISSISSIPPI
VALLEY AND THE RESIDUAL MOISTURE BECOMES FORCED BELOW 925MB. THIS
DOES LEAD TO SOME CONCERN FOR LOW CLOUDS BECOMING TRAPPED OVER THE
AREA ON WEDNESDAY NIGHT. SFC TO 925MB DELTA-T VALUES ARE ONLY AROUND
8-9C...SO LAKE INFLUENCE WILL BE BE LIMITED. BUT IF CLOUDS ARE STILL
PRESENT FROM WEDNESDAY...THE INCREASING SUBSIDENCE INVERSION AND
LACK OF MIXING DURING THE OVERNIGHT HOURS WILL TRY TO KEEP THEM IN
PLACE. THUS...WILL TRY TO HOLD ONTO MORE OF A PARTLY/MOSTLY CLOUDY
SKY FOR WEDNESDAY NIGHT AND THEN HAVE DAYTIME MIXING TRY TO REDUCE
CLOUDS SOMEWHAT ON THURSDAY. ONE THING TO WATCH ON THURSDAY WILL BE
THE INCREASING SFC-925MB LAPSE RATES IF BREAKS DO OCCUR. THIS COULD
LEAD TO DIURNAL CU REDEVELOPING OVER INTERIOR WEST LOCATIONS WHERE
LAPSE RATES APPROACH 9C/KM. WITH PLENTY OF DRY AIR...THURSDAY NIGHT
INTO FRIDAY SHOULD BE DRY AND PARTLY/MOSTLY CLEAR EVEN THOUGH A
SHORTWAVE MOVES ACROSS THE AREA IN THE NORTHWEST FLOW.
EXPECT GRADUAL WARMING TEMPERATURES THROUGH THE WEEK...ESPECIALLY
FOR THURSDAY AND FRIDAY WITH THE LATE MARCH SUNSHINE. WEDNESDAY
SHOULD SEE HIGHS IN THE MID-UPPER 30S AND THEN UPPER 30S THROUGH MID
40S FOR THURSDAY AND FRIDAY. 00Z ECMWF AND MOST OF IT/S ENSEMBLE
MEMBERS HAVE KSAW REACHING THE LOW 40S ON FRIDAY AND SATURDAY.
THUS...IT IS LOOKING LIKE OUR OFFICE WILL END UP REACHING 40 DEGREES
AND KEEP THIS MARCH FROM BEING THE FIRST MARCH ON RECORD WHERE WE
DIDN/T REACH 40 DEGREES.
CHANGES LOOK TO ARRIVE FOR THIS WEEKEND...AS A STRONG SHORTWAVE
DIVES SOUTHEAST THROUGH CENTRAL CANADA AND INTO THE UPPER GREAT
LAKES FOR LATE SATURDAY INTO SUNDAY. MODELS ARE FAIRLY CONSISTENT
ON THIS IDEA...WHICH INCREASES CONFIDENCE INTO THE FIRST PART OF
NEXT WEEK. AT THIS TIME...LOOKS LIKE ASSOCIATED COLD FRONT WILL
MOVE THROUGH ON SATURDAY AFTERNOON/NIGHT. BASED OFF THICKNESS AND
THERMAL PROFILES...LOOKS LIKE A MIX OF RAIN/SNOW AS THE FRONT MOVES
THROUGH. WITH THE DRY HIGH IN PLACE...QPF AMOUNTS LOOK TO BE
LIMITED AT THIS POINT WITH THE INITIAL FRONT. THEN BEHIND THE FRONT
ON SUNDAY...MAIN SHORTWAVE MOVES THROUGH AND COLDER 850MB TEMPS
SURGE SOUTHEAST AND REACH -12C/ECMWF OR -10C/GFS BY MONDAY MORNING.
WITH THE NORTHWEST FLOW GENERATED BY THE HIGH OVER THE NORTHERN
PLAINS...WOULD SOME LAKE EFFECT SNOW SHOWERS IN THE NORTHWEST
WIND FAVORED LOCATIONS FOR MONDAY. WILL TREND POPS UP SLIGHTLY FROM
A GENERAL MODEL CONSENSUS FOR THAT TIME FRAME NEAR LAKE SUPERIOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 136 PM EDT MON MAR 25 2013
AS LOW LEVEL MOISTURE REMAIN IN PLACE ACROSS MOST OF THE UPPER
PENINSULA...EXPECT CEILINGS AND VISIBILITIES TO REMAIN MVFR TO
INTERMITTENT IFR CONDITIONS THROUGH THIS TAF PERIOD. TEMPERATURE
PROFILES ALONG WITH BROAD CYCLONIC FLOW SUPPORT MAINLY -SHSN THROUGH
THIS AFTERNOON BEFORE MIXING WITH OR CHANGING TO -FZDZ OVERNIGHT.
WINDS WILL REMAIN OUT OF THE NORTH TO NORTHWEST AT EACH TAF SITE WITH
GUSTS THIS AFTERNOON REACHING AROUND THE 20KT RANGE AS THE PRESSURE
GRADIENT INTENSIFIES BETWEEN LOW PRESSURE SOUTHEAST OF THE AREA AND
HIGH PRESSURE TO THE WEST OF THE AREA.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 356 PM EDT MON MAR 25 2013
HIGH PRESSURE IN PLACE OVER THE NORTHERN PLAINS AND LOW PRESSURE
SHIFTING EASTWARD FROM THE OHIO VALLEY TO EASTER SEABOARD WILL LEAD
TO A TIGHT PRESSURE GRADIENT OVER LAKE SUPERIOR THROUGH TUESDAY.
THIS WILL RESULT IN NORTHERLY TO NORTHWESTERLY WINDS 15 TO 25 KNOTS.
BEYOND TUESDAY AFTERNOON...HIGH PRESSURE WILL BUILD INTO THE UPPER
GREAT LAKES REGION KEEPING WINDS GENERALLY BELOW 20 KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KEC
LONG TERM...SRF
AVIATION...KEC
MARINE...KEC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
138 PM EDT MON MAR 25 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 509 AM EDT MON MAR 25 2013
WV IMAGERY AND RUC ANALYSIS INDICATED WEAK MID/UPPER LEVEL NE FLOW
THROUGH THE NRN GREAT LAKES BETWEEN AND LOW OVER THE OHIO VALLEY AND
A RIDGE OVER HUDSON BAY. AT THE SFC...NE WINDS ALSO PREVAILED ACROSS
THE REGION BETWEEN LOW PRESSURE OVER SRN OHIO AND A RIDGE FROM
SASK/MANITOBA INTO THE PLAINS. MARGINAL OVER LAKE INSTABILITY WITH
850 MB TEMPS AROUND -10C ONLY SUPPORTED PATCHY LIGHT SNOW OR
FLURRIES INTO N CNTRL UPPER MI AIDED BY UPSLOPE FLOW (25-30 KT
950-900 MB WINDS) INTO THE HIGHER TERRAIN. UPSTREAM...PERIODS OF -FZDZ
WERE OBSERVED AT CYYU AND CYGQ DURING PERIODS WHERE SATELLITE
IMAGERY SUGGESTED MOISTURE WAS MORE SHALLOW.
AS THE NEXT BATCH OF 925-750 MB MOISTURE MOISTURE MOVES INTO THE
REGION...THE POTENTIAL FOR LIGHT PCPN WILL INCREASE AND CONTINUE
INTO TONIGHT. WITH 850 MB TEMPS AND MIN TEMPS IN THE MOIST LAYER
AROUND -10C...AND THE STRONGEST UPWARD MOTION BELOW THE DGZ...MAINLY
JUST SMALL SNOWFLAKES OR EVEN ICE PELLETS ARE EXPECTED WITH A LOW
SNOW/WATER RATIO. ANY ACCUMULATIONS SHOULD AMOUNT TO AN INCH OR LESS.
GIVEN THE UPSTREAM OBS AND TRENDS FROM THE LAST SEVERAL DAYS...SOME
PATCHY -FZDZ ALSO MAY MIX WITH THE -SHSN/FLURRIES THIS MORNING
BEFORE THE DEEPER MOISTURE BECOMES ESTABLISHED.
AS THE MOIST LAYER BECOMES MORE SHALLOW LATE TONIGHT OVER NCNTRL AND
TEMPS MODERATE TO NEAR -10C AT THE TOP OF MOIST LAYER PER MODEL
SNDGS...-FZDZ WILL AGAIN BE POSSIBLE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 435 AM EDT MON MAR 25 2013
UPPER MICHIGAN WILL REMAIN UNDER THE INFLUENCE OF THE LINGERING
SFC-500MB TROUGH ON TUESDAY. IT WILL BE PUSHED EASTWARD THROUGH MID
WEEK AS THE 500MB HIGH OVER HUDSON BAY SINKS SOUTH INTO THE REGION.
SLOWLY WARMING HIGH TEMPERATURES THROUGH THE PERIOD...WITH ALL AREAS
/OR NEARLY ALL AREAS/ PUSHING ABOVE FREEZING FROM WEDNESDAY ON...AND
INTO THE LOW 40S FOR THE WEEKEND. DRY WEATHER SHOULD BE THE RULE
WEDNESDAY AFTERNOON THROUGH FRIDAY NIGHT AS THE SFC HIGH TO OUR WEST
CENTERS ITSELF ACROSS THE REGION. LOOK FOR SLOWLY DIMINISHING
UPSLOPE CHANCES OF LIGHT SNOW SHOWERS WITH THE SHALLOW MOISTURE AT
OR BELOW 800MB AND DEEPENING INVERSION HEIGHTS. THE NEXT ROUND OF
PRECIPITATION LOOKS TO BE ASSOCIATED WITH THE 500MB LOW OVER HUDSON
BAY SATURDAY SWINGING A SIZABLE TROUGH ACROSS THE NORTHERN PLAINS
THROUGH THE UPPER GREAT LAKES THROUGH THE WEEKEND. THE SFC HIGH WILL
BE SHIFTED SOUTHEAST...AND A COLD FRONT WILL LIKELY SWING ACROSS
WESTERN LAKE SUPERIOR LATE SATURDAY...AND SLOWLY SLIDE EAST OF LAKE
SUPERIOR/UPPER MI SUNDAY BY LATE AFTERNOON. THE 25/00Z ECMWF LOOKS
TO BE A BIT DEEPER AND SLOWER WITH THE PASSAGE OF THE COLD FRONT.
THE 25/00Z GFS KEEP MUCH OF THE ENERGY TO OUR SOUTH...AND AS A
RESULT MUCH OF THE PRECIPITATION. STILL COULD GET AROUND 0.05-0.2IN
OF LIQUID OUT OF THE FRONTAL PASSAGE.
TEMPERATURES FOR THE FIRST HALF OF THE WEEKEND WERE WARMED
SLIGHTLY...WITH A CONTINUED NEED FOR MIXED PRECIPITATION AS HIGH
TEMPERATURES HOVER AROUND 40F. WAA WILL RESULT IN 850MB TEMPS RISING
FROM AROUND -7C AT 12Z FRIDAY TO A CWA AVERAGED -1.5C BY 00Z
SUNDAY...AND POSSIBLY UP TO 0C NEAR MENOMINEE AT 06Z SUNDAY. WAS A
BIT HESITANT TO JUST HAVE RAIN IN THE FORECAST FOR SATURDAY
NIGHT...GIVEN THE TIME OF DAY AND THE FACT THAT IT WAS DAY 5-6...BUT
WITH LOWS NEAR 32F ALL RAIN WOULD BE A SERIOUS POSSIBILITY. LATER
SHIFTS WILL HAVE PLENTY OF TIME TO REDEFINE THE COVERAGE AREA OF
BOTH RAIN AND SNOW FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 136 PM EDT MON MAR 25 2013
AS LOW LEVEL MOISTURE REMAIN IN PLACE ACROSS MOST OF THE UPPER
PENINSULA...EXPECT CEILINGS AND VISIBILITIES TO REMAIN MVFR TO
INTERMITTENT IFR CONDITIONS THROUGH THIS TAF PERIOD. TEMPERATURE
PROFILES ALONG WITH BROAD CYCLONIC FLOW SUPPORT MAINLY -SHSN THROUGH
THIS AFTERNOON BEFORE MIXING WITH OR CHANGING TO -FZDZ OVERNIGHT.
WINDS WILL REMAIN OUT OF THE NORTH TO NORTHWEST AT EACH TAF SITE WITH
GUSTS THIS AFTERNOON REACHING AROUND THE 20KT RANGE AS THE PRESSURE
GRADIENT INTENSIFIES BETWEEN LOW PRESSURE SOUTHEAST OF THE AREA AND
HIGH PRESSURE TO THE WEST OF THE AREA.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 509 AM EDT MON MAR 25 2013
HIGH PRESSURE IN PLACE OVER THE NORTHERN PLAINS AND LOW PRESSURE
MOVING EASTWARD ACROSS THE TENNESSEE VALLEY WILL LEAD TO A TIGHT
PRESSURE GRADIENT OVER LAKE SUPERIOR THROUGH TUESDAY. THIS WILL
RESULT IN NORTHERLY WINDS 15 TO 25 KNOTS. FOR TUESDAY AFTERNOON AND
BEYOND...HIGH PRESSURE WILL SPRAWL ACROSS THE GREAT LAKES...KEEPING
WINDS BELOW 20 KNOTS OUT OF THE NORTH AND WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...KEC
MARINE...JLB