Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 04/12/12
AREA FORECAST DISCUSSION
NWS DENVER CO
808 PM MDT WED APR 11 2012
.UPDATE...
&&
.SHORT TERM...THE INITIAL FIRST ROUND OF SHOWERS AND STORMS ARE
EXITING INTO WYOMING WITH A SECOND WAVE TO ROTATE THROUGH THE AREA
THROUGH THE NIGHT. SHOWERS AND THUNDERSTORMS ARE ALREADY
INCREASING AGAIN OVER THE MOUNTAINS AT THIS HOUR AND SOME OF THIS
WILL ADVECT ACROSS PORTIONS OF THE CWA THROUGH LATER IN THE NIGHT.
THE BRUNT OF THE ACTIVITY WILL BE OVER THE PALMER DIVIDE BEFORE
WEAKENING AS IT MOVE INTO THE MORE STABLE AIRMASS. ONLY A FEW
MINOR CHANGES TO CURRENT GRIDS.
.AVIATION...WITH CONSIDERABLE DOWNSLOPE FLOW OVER THE PLAMER
DIVIDE AT APA/DEN WOULD EXPECT SHOWERS TO DISSIPATE AS THE SHOWERS
MOVE TO THE NORTH AND NORTHEAST. WILL ADD SOME MORE CLOUDS AND A
VCSH TO THE LOCAL TERMINALS THROUGH ABOUT 08Z. DRIER AIR MOVES IN
BEHIND THIS WAVE WITH A S-SW LOW LVL FLOW AND FOG/STATUS THREAT
LOOK QUITE LOW.
&&
.PREV DISCUSSION... /ISSUED 355 PM MDT WED APR 11 2012/
SHORT TERM...WATER VAPOR LOOPS SHOW SHORTWAVE ROTATING ACROSS
CENTRAL AND SOUTHERN COLORADO. CONVECTION CONTINUES TO DEVELOP
ACROSS SUMMIT AND PARK COUNTIES ASSOCIATED WITH THIS WAVE...WITH
STORMS TRYING TO DEVELOP ACROSS THE FOOTHILLS. OVER THE PLAINS...
SURFACE ANALYSIS SHOWS CYCLONE HAD DEVELOPED ACROSS DENVER AREA
WITH LAPS ANALYSIS INDICATING CAPES OF 1000-1500 J/KG ALONG URBAN
CORRIDOR FROM SOUTHERN LARIMER COUNTY SOUTH INTO EASTERN DOUGLAS
AND NORTHWEST ELBERT COUNTIES. STILL QUITE A BIT OF CIN STILL
HOLDING ON ACROSS PLAINS...WITH ACARS SOUNDINGS SHOWING AIRMASS
STILL CAPPED. SHOULD SEE CONVECTION BEGIN TO SPREAD EAST INTO THE
URBAN CORRIDOR BY THE EVENING AS WAVE HEADS TOWARD THE NORTHEAST.
FEEL THAT ANY BOUNDARIES FROM MOUNTAINS AND FOOTHILLS SHOULD HELP
ERODE ANY LINGERING CAPS. MODELS WEAKEN THE CYCLONE BY 00Z AND
PUSH IT NORTHEAST INTO WELD COUNTY. THE LATEST HRRR RUN STILL
HOLDS ONTO SOME SORT OF A CONVERGENCE AREA FROM EAST OF DIA INTO
NORTHWEST ELBERT COUNTY INTO THE EARLY EVENING AND MAY STILL BE
THE FOCUS FOR THE STRONGER STORMS. THREATS TO BE HAIL ALONG WITH
GUSTY WINDS...ESPECIALLY WITH THE STRONGER STORMS. WILL STILL NEED
TO WATCH OUT FOR WEAK TORNADOES ALONG THE BOUNDARIES. WAVE TO MOVE
ACROSS THE AREA DURING THE EVENING...FEEL THE CURRENT POPS LOOK
REASONABLE. MODEL QPF GENERALLY LIGHT...THOUGH GFS LOOKS A BIT
ROBUST. ANOTHER NEXT WEAKER WAVE APPEARS TO BE MOVING ACROSS
UTAH...THOUGH CONVECTION NOT AS ABUNDANT. MODELS PICK UP ON THIS
SECOND WAVE AS WELL...BRINGING IT ACROSS THE AREA AROUND MIDNIGHT.
THERE IS SOME LIGHT MODEL QPF WITH THIS FEATURE ACROSS AREA...
MAINLY AFTER MIDNIGHT. ADDED SOME LOW POPS FOR FOOTHILLS AND
ADJACENT PLAINS FOR THIS WAVE...WITH LINGERING SHOWERS OVER THE
FAR NORTHEAST CORNER TOWARDS MORNING. STILL SOME MOISTURE ACROSS
MOUNTAINS TO KEEP THE SLIGHT CHANCE OF SNOW SHOWERS OVER ZONES 31
AND 33. AS FOR RED FLAG HILITES...WILL HOLD ON TO THE WARNINGS FOR
THE MOUNTAIN VALLEYS THROUGH 8PM THIS EVENING..THOUGH HUMIDITY
READINGS HAVE BEEN SLOWLY INCREASING ACROSS PARK COUNTY. ON
THURSDAY...SHORT WAVE RIDGE WILL BE OVER THE AREA DURING THE
MORNING WITH THE SOUTHWEST FLOW ALOFT INCREASING AGAIN BY
AFTERNOON ACROSS THE MOUNTAINS. MODELS SHOW SOME WEAK QG ASCENT
SLIDING ACROSS THE NORTHEAST CORNER DURING THE AFTERNOON. NAM AND
GFS GENERATE SOME LIGHT QPF ACROSS THE PLAINS. FOR NOW WILL KEEP
THE POPS AND WEATHER LIMITED TO THE NORTHEAST CORNER. FOR THE
MOUNTAINS...CROSS SECTIONS SHOW MOISTURE INCREASING AGAIN DURING
THE AFTERNOON. CURRENT CHANCE POPS STILL LOOK ON TRACK.
TEMPERATURES LOOK COOL ENOUGH DURING THE AFTERNOON FOR A MIX OF
RAIN AND SNOW.
LONG TERM...SOME CONVERGENCE IN THE MODELS TODAY ON THIS WEEKENDS
STORM...THOUGH STILL SIGNIFICANT QUESTIONS ABOUT THE TRACK AND
INTENSITY. THE MOST IMPORTANT FACTOR NOW IS LOOKING LIKE THE
TEMPERATURES.
AHEAD OF THE STORM WE WILL HAVE DRY SSW FLOW OVER THE MOUNTAINS AND
PALMER DIVIDE ON FRIDAY AFTERNOON. COULD BE APPROACHING RED FLAG
CONDITIONS FOR A FEW HOURS ON FRIDAY AFTERNOON. FURTHER NORTH THE
WINDS WILL NOT BE AS STRONG AND THEY COULD TURN NORTHERLY AND BRING
IN COOLER AIR. WHILE LOW LEVELS WILL BE DRY...HIGH LEVEL MOISTURE
WILL BE INCREASING BRINGING MORE CLOUD COVER. JUST A SLIGHT CHANCE
OF SHOWERS INTO THE MOUNTAINS LATE...BUT I DID TRIM HIGHS BACK A
COUPLE OF DEGREES FOR THE CLOUD COVER.
FOR THE MAIN FEATURE...BETTER AGREEMENT NOW ON THE INTERACTION
BETWEEN TWO SHORTWAVES...WITH CONSENSUS SHOWING A SLOW MOVING LOW
WITH THE SHORTWAVES MAKING IT WOBBLE AS IT MOVES OVER THE ROCKIES.
GFS HAS BEEN MAINTAINING ITS INTENSITY BUT HAS THE SYSTEM MOVING
FASTER NOW...RESULTING IN ABOUT A 30 HOUR PERIOD OF GOOD UPSLOPE.
ECMWF IS NOT AS SPLIT BUT IS A BIT FASTER. GFS HAS THE LOW COMING
RIGHT OVER US...AND AS A RESULT PUTS DENVER ON THE SOUTH EDGE OF THE
HEAVY PRECIPITATION. MEANWHILE THE ECMWF HAS ITS LOW MORE
CONSOLIDATED THAN YESTERDAYS WITH A COMPROMISE POSITION ACROSS
SOUTHEASTERN COLORADO. THIS SOLUTION IS LOOKING MORE REASONABLE AND
WILL TREND THE FORECAST TOWARD IT. STILL A LONG PERIOD...MAYBE 24
HOURS...OF GOOD UPSLOPE WITH LOW STABILITY AND LOTS OF MOISTURE
AVAILABLE. THE ODDS OF A COUPLE FEET OF SNOW IN THE FOOTHILLS ARE
LOOKING BETTER. GFS CONTINUES TO PRODUCE 50 INCHES OF SNOW IN ITS
FAVORED UPSLOPE AREA...AND THE ECMWF NUMBERS ARE JUST A LITTLE LOWER
DUE TO THE FASTER MOVEMENT.
THE DETAILS WILL BE MORE IMPORTANT FOR THE PLAINS PRECIP...THOUGH A
PRETTY GOOD CHANCE OF GETTING A WETTING RAIN/SNOW EVENT ESPECIALLY
NORTH OF INTERSTATE 70. THE BIG QUESTION IS THE TEMPERATURE. MODEL
CONSENSUS HAS THE SNOW LEVEL RIGHT AROUND THE DENVER AREA...AT THIS
POINT WOULD FAVOR THE IDEA OF RAIN CHANGING TO SNOW SATURDAY NIGHT
AND STAYING SNOW ON SUNDAY BUT A COUPLE DEGREES EITHER WAY WOULD
MAKE A HUGE DIFFERENCE. WITH THE AMOUNT OF PRECIPITATION
POSSIBLE...THIS COULD STILL HAVE SOME IMPACT ESPECIALLY THE WEIGHT
OF THE WET SNOW ON VEGETATION. TRAVEL IMPACTS SHOULD BE QUITE
LIMITED WITH SOIL TEMPERATURES IN THE UPPER 40S AND AIR TEMPERATURES
THAT SHOULD REMAIN AROUND FREEZING. HIGH MODEL SNOW ACCUMULATIONS
EAST OF THE MOUNTAINS LOOK UNREALISTIC DUE TO THE METHODOLOGY
UNDERESTIMATING LOW LEVEL TEMPERATURES...BUT EVEN WITH SOME RAIN AND
LOW SNOW/LIQUID RATIOS THERE COULD BE SOME HEAVY WET SNOW.
FAIRLY QUIET FOR MONDAY THROUGH WEDNESDAY...PROBABLY STABLE AND DRY
ON THE PLAINS...HINTS OF A LITTLE MOISTURE IN WESTERLY FLOW FOR THE
MOUNTAINS SO I HELD ON TO LOW POPS THERE. I DID START TRIMMING
TEMPERATURES MAINLY ALONG THE FRONT RANGE FOR SOME EXPECTED SNOW
COVER IN THE EARLY PART OF THE WEEK...OTHERWISE IT WOULD BE A FAIRLY
PROMPT WARMUP.
AVIATION...CONVECTION FIRING ALONG FOOTHILLS AND PALMER
DIVIDE...WITH DENVER AREA STILL CAPPED. STILL SOME QUESTION ABOUT
STORMS AFFECTED THE AREA AIRPORTS...FEEL THE VCTS THE BEST WAY TO
GO FOR NOW. SLIGHT CHANCE FOR SHOWERS AFTER MIDNIGHT AS NEXT WAVE
MOVES THROUGH...THREAT APPEARS TOO LOW TO INCLUDE IN TAF. WILL
MAINTAIN VFR CONDITIONS...THOUGH CEILINGS OF 5000-6000 FEET
POSSIBLE THROUGH THE EVENING. GUSTY SOUTHEAST WINDS TO CONTINUE
FOR MUCH OF THE EVENING...THEN DECREASING AS SWITCHING TO THE
SOUTHWEST. WINDS TO TRANSITION TO THE NORTHWEST BY 18Z THURSDAY
WITH SPEEDS AROUND 12 KTS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...NONE
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....GIMMESTAD
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION...CORRECTION...
NWS DENVER CO
410 PM MDT TUE APR 10 2012
.SHORT TERM...CUMULUS STILL TRYING TO DEVELOP ALONG FOOTHILLS AND
PALMER DIVIDE AS WELL AS ALONG A WEAK BOUNDARY SOUTH AND EAST OF
DENVER. LAPS SURFACE ANALYSIS SHOWING CAPE VALUES AROUND 500 J/KG
IN THIS AREA...LESS ELSEWHERE ALONG WITH SOME CIN. LATEST RUC AND
NAM RUNS STILL SHOWING SOME LIGHT QPF ACROSS SOUTHERN FOOTHILLS
AND ALONG THE PALMER DIVIDE FOR THIS EVENING...WITH FORECAST
SOUNDINGS STILL HOLDING ON TO SOME CAPE. WILL MAINTAIN A SLIGHT
CHANCE OF THUNDER FOR EARLY THIS EVENING. IF STORMS DO
DEVELOP...GUSTY WINDS THE MAIN THREAT. FOR TONIGHT...LOW LEVEL
SOUTHEASTERLIES REDEVELOP ACROSS PLAINS WHICH WILL ADVECT MORE LOW
LEVEL MOISTURE WESTWARD TOWARD FOOTHILLS. FORECAST SOUNDINGS SHOWING
MORE OF A DRIZZLE PROFILE THAT RAIN SHOWERS...ESPECIALLY EAST OF
DENVER. CURRENT GRIDS SHOW ALL OF PLAINS WITH AREAS OF FOG...AND
THAT SEEMS REASONABLE AFTER 06Z. MAIN CHANGE WILL BE TO GO WITH
AREAS OF DRIZZLE RATHER THAN RAIN SHOWERS. THOUGHT ABOUT INCLUDING
FOOTHILLS IN THE MUCK...BUT LOW LEVEL MOISTURE LOOKS SHALLOW WITH
NOT MUCH ADVECTION. WILL NOT ADD FOG OR DRIZZLE FOR FOOTHILLS. ON
THURSDAY... SOUTHWEST FLOW ALOFT INCREASES AHEAD OF DEVELOPING UPPER
TROUGH OVER WEST COAST. THE LINGERING DRIZZLE AND FOG SHOULD BE
DISSIPATED BY THE AFTERNOON. MODELS SHOWING UPPER LEVEL DISTURBANCE
MOVING ACROSS THE AREA DURING THE AFTERNOON...SHOULD HELP TO
GENERATE SOME CONVECTION...MAINLY EAST OF THE DIVIDE WHERE
SUFFICIENT SHEAR AND LOW LEVEL MOISTURE WILL BE IN PLACE. CURRENT
CHANCE POPS SEEM ON TRACK FOR NOW. A COUPLE OF ITEMS OF CONCERN.
FIRSTLY...THERE IS SOME THREAT OF SEVERE STORMS ALONG URBAN CORRIDOR
AND PALMER DIVIDE WHERE MODELS GENERATE CAPES CLOSE TO 1500 J/KG. SO
POTENTIAL IS THERE FOR HAIL ALONG WITH GUSTY WINDS. FURTHER
EAST...AIRMASS LOOKS A BIT TOO STABLE...WHICH COULD LIMIT STORM
THREAT. BUT WILL KEEP THE LOW CHANCE OF THUNDER IN CASE BOUNDARIES
ARE SUFFICIENT TO HELP POP SOME STORMS. NEXT CONCERN IS THE INCREASE
IN WINDS ALONG WITH LOW HUMIDITY FOR MOUNTAIN VALLEYS. WILL HOIST A
RED FLAG WARNING FOR THE VALLEYS FROM NOON THROUGH 8PM. SOME
QUESTION FOR SOUTH PARK AS THERE IS ALSO A CHANCE FOR STORMS. THIS
MAY INCREASE THE RED FLAG THREAT WITH THE OUTFLOW CONCERN FOR
OUTFLOW WIND. ALSO A SMALL THREAT OF DRY LIGHTNING BUT NOT THE MAIN
CONCERN.
.LONG TERM...WEAK SHORTWAVE WILL PASS ACROSS EASTERN COLORADO
WEDNESDAY EVENING. CURRENT FORECAST OF CHANCE POPS WITH SOME
THUNDERSTORMS STILL LOOKS GOOD. AVAILABLE ENERGY WILL BE
DIMINISHING AS THE CONVECTION MOVES EAST...BUT THERE SHOULD BE
PLENTY OF MOISTURE CONVERGENCE INTO ANY GUST FRONTS TO KEEP THINGS
GOING IN DESPITE THE COOLING BOUNDARY LAYER. THURSDAY LOOKS FAIRLY
QUIET WITH COOL MOIST AIR POOLING EAST OF A DEVELOPING DRYLINE.
PROBABLY TOO COOL FOR CONVECTION IN OUR AREA...DROPPED HIGHS A BIT
NEAR THE EASTERN BORDER DUE TO LIKELY CLOUD COVER THROUGH MIDDAY.
WEAK LIFT MOVES IN BY FRIDAY...STILL PROBABLY A BIT STABLE BUT
I WILL ALLOW FOR SOME LATE DAY CONVECTION.
THE BIG EVENT IS THE UPPER TROUGH MOVING THROUGH THE WEST THIS
WEEKEND. MODELS CONTINUE TO SHOW SOME LARGE SCALE AGREEMENT...BUT
ARE QUITE DIFFERENT WITH THE DETAILS OF THE FLOW. LAST SEVERAL
RUNS OF THE GFS HAVE HAD A CLOSED LOW THAT TAKES 2-3 DAYS TO MOVE
FROM NORTHERN ARIZONA TO NORTHEASTERN COLORADO...DUMPING SEVERAL
INCHES OF PRECIPITATION ON THE NORTH SIDE OF THE LOW
TRACK...ESPECIALLY IN THE FRONT RANGE FOOTHILLS WHICH WOULD
PRODUCE SEVERAL FEET OF SNOW. ECMWF CONTINUES TO SPLIT THE ENERGY
IN THE TROUGH MORE. SOME OF THE ECMWF RUNS HAVE PRODUCED
SIGNIFICANT PRECIPITATION IN A SHORTER DURATION EVENT...BUT THE
CONSENSUS HAS BEEN TO HAVE THE SECONDARY JET STREAM SPLIT OFF THE
SOUTHERN PART OF THE TROUGH WHILE THE NORTHERN PART PASSES OVER
COLORADO SATURDAY NIGHT...WITH THE SOUTHERN PART BEING SLOWER AND
PRETTY FAR SOUTH TO HAVE MUCH AFFECT ON NORTHERN COLORADO. THE
SLOWNESS OF THE GFS SEEMS EXTREME GIVEN A LARGER SCALE PATTERN
WITHOUT DOWNSTREAM BLOCKING...THE SECOND PIECE OF ENERGY SHOULD
PRODUCE SOME SPLITTING OR WOBBLING OF THE LOW. CANNOT DISCOUNT
SOME KIND OF WOBBLY LOW BUT WE WILL CONTINUE TO DISCOUNT WHAT
SEEMS LIKE THE UNLIKELY GFS SOLUTIONS THAT KEEP US IN THE RIGHT
SPOT FOR HEAVY PRECIPITATION FOR 60 HOURS. ESRL/PSD REANALYSIS
PROBABILITIES SUPPORT THIS IDEA WITH ONLY LOW CHANCES OF HEAVY
PRECIPITATION...BUT PRETTY HIGH PROBABILITIES OF A FEW TENTHS OF
AN INCH. THE ECMWF SOLUTIONS WOULD HAVE A QUICK SHOT OF
PRECIPITATION SATURDAY INTO EARLY SUNDAY...THEN LITTLE OR NOTHING
AFTER THAT. WITH A HIGH LIKELIHOOD OF A CLOSED LOW TO THE
SOUTH...WOULD STILL GIVE HEED TO THE CHANCE OF ANOTHER ROUND OF
PRECIPITATION THAT COULD LAST A WHILE. EVEN THESE SOLUTIONS COULD
GIVE A SUBSTANTIAL AMOUNT OF PRECIPITATION OVER A LONG TIME. AS
FOR TEMPERATURES...PRETTY WARM FOR MUCH SNOW IN DENVER. MODEL
TEMPERATURES WOULD SUGGEST THE RAIN/SNOW LINE SOMEWHERE AROUND 5-6
THOUSAND FEET WHICH COULD LESSEN THE IMPACT OF ANY SNOW WITH
A WARM GROUND AND AIR TEMPERATURES NEAR OR ABOVE FREEZING THROUGH
MUCH OF THIS TIME.
BOTTOM LINE...FOR NOW NOT MUCH CHANGE IN THE FORECAST...WILL RAISE
THE POPS A BIT ESPECIALLY SATURDAY INTO EARLY SUNDAY WHICH IS THE
MOST LIKELY TIME.
&&
.AVIATION...SOUTHEAST WIND TO GRADUALLY DECREASE...BECOMING
SOUTHERLY AS DRAINAGE PATTERN DEVELOPS. LOW LEVEL MOISTURE TO
INCREASE AFTER MIDNIGHT...ALLOWING FOR LOW CLOUDS AND FOG TO
DEVELOP AS WELL AS SOME DRIZZLE. COULD SEE IFR CONDITIONS FROM
10Z-15Z AT AREA AIRPORTS...AFFECTING MAINLY DIA. CHANCE FOR STORMS
AFTER 18Z...MAINLY ALONG FOOTHILLS AND PALMER DIVIDE AS WELL AS
AREAS EAST AND SOUTHEAST OF DENVER. WILL HOLD OFF INCLUDING IN
TAFS FOR NOW. POTENTIAL FOR OUTFLOW BOUNDARIES FROM THOSE STORMS
AFFECTING THE AREA AIRPORTS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TO 8 PM MDT WEDNESDAY FOR COZ211-213-
214.
&&
$$
SHORT TERM...D-L
LONG TERM....GIMMESTAD
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER CO
357 PM MDT TUE APR 10 2012
.SHORT TERM...CUMULUS STILL TRYING TO DEVELOP ALONG FOOTHILLS AND
PALMER DIVIDE AS WELL AS ALONG A WEAK BOUNDARY SOUTH AND EAST OF
DENVER. LAPS SURFACE ANALYSIS SHOWING CAPE VALUES AROUND 500 J/KG
IN THIS AREA...LESS ELSEWHERE ALONG WITH SOME CIN. LATEST RUC AND
NAM RUNS STILL SHOWING SOME LIGHT QPF ACROSS SOUTHERN FOOTHILLS
AND ALONG THE PALMER DIVIDE FOR THIS EVENING...WITH FORECAST
SOUNDINGS STILL HOLDING ON TO SOME CAPE. WILL MAINTAIN A SLIGHT
CHANCE OF THUNDER FOR THIS REGION FOR THIS EVENING...DROPPING THE
SLIGHT CHANCE ELSEWHERE. WILL ALSO KEEP A PORTION OF ZONE 34 OVER
PARK COUNTY. IF STORMS DO DEVELOP...GUSTY WINDS THE MAIN THREAT.
FOR TONIGHT...LOW LEVEL SOUTHEASTERLIES REDEVELOP ACROSS PLAINS
WHICH WILL ADVECT MORE LOW LEVEL MOISTURE WESTWARD TOWARD
FOOTHILLS. FORECAST SOUNDINGS SHOWING MORE OF A DRIZZLE PROFILE
THAT RAIN SHOWERS...ESPECIALLY EAST OF DENVER. CURRENT GRIDS SHOW
ALL OF PLAINS WITH AREAS OF FOG...AND THAT SEEMS REASONABLE AFTER
06Z. MAIN CHANGE WILL BE TO GO WITH AREAS OF DRIZZLE RATHER THAN
RAIN SHOWERS. THOUGHT ABOUT INCLUDING FOOTHILLS IN THE MUCK...BUT
LOW LEVEL MOISTURE LOOKS SHALLOW WITH NOT MUCH ADVECTION. WILL NOT
ADD FOG OR DRIZZLE FOR FOOTHILLS. ON THURSDAY... SOUTHWEST FLOW
ALOFT INCREASES AHEAD OF DEVELOPING UPPER TROUGH OVER WEST COAST.
THE LINGERING DRIZZLE AND FOG SHOULD BE DISSIPATED BY THE
AFTERNOON. MODELS SHOWING UPPER LEVEL DISTURBANCE MOVING ACROSS
THE AREA DURING THE AFTERNOON...SHOULD HELP TO GENERATE SOME
CONVECTION...MAINLY EAST OF THE DIVIDE WHERE SUFFICIENT SHEAR AND
LOW LEVEL MOISTURE WILL BE IN PLACE. CURRENT CHANCE POPS SEEM ON
TRACK FOR NOW. A COUPLE OF ITEMS OF CONCERN. FIRSTLY...THERE IS
SOME THREAT OF SEVERE STORMS ALONG URBAN CORRIDOR AND PALMER
DIVIDE WHERE MODELS GENERATE CAPES CLOSE TO 1500 J/KG. SO
POTENTIAL IS THERE FOR HAIL ALONG WITH GUSTY WINDS. FURTHER
EAST...AIRMASS LOOKS A BIT TOO STABLE...WHICH COULD LIMIT STORM
THREAT. BUT WILL KEEP THE LOW CHANCE OF THUNDER IN CASE BOUNDARIES
ARE SUFFICIENT TO HELP POP SOME STORMS. NEXT CONCERN IS THE
INCREASE IN WINDS ALONG WITH LOW HUMIDITY FOR MOUNTAIN VALLEYS.
WILL HOIST A RED FLAG WARNING FOR THE VALLEYS FROM NOON THROUGH
8PM. SOME QUESTION FOR SOUTH PARK AS THERE IS ALSO A CHANCE FOR
STORMS. THIS MAY INCREASE THE RED FLAG THREAT WITH THE OUTFLOW
CONCERN FOR OUTFLOW WIND. ALSO A SMALL THREAT OF DRY LIGHTNING BUT
NOT THE MAIN CONCERN.
.LONG TERM...WEAK SHORTWAVE WILL PASS ACROSS EASTERN COLORADO
WEDNESDAY EVENING. CURRENT FORECAST OF CHANCE POPS WITH SOME
THUNDERSTORMS STILL LOOKS GOOD. AVAILABLE ENERGY WILL BE
DIMINISHING AS THE CONVECTION MOVES EAST...BUT THERE SHOULD BE
PLENTY OF MOISTURE CONVERGENCE INTO ANY GUST FRONTS TO KEEP THINGS
GOING IN DESPITE THE COOLING BOUNDARY LAYER. THURSDAY LOOKS FAIRLY
QUIET WITH COOL MOIST AIR POOLING EAST OF A DEVELOPING DRYLINE.
PROBABLY TOO COOL FOR CONVECTION IN OUR AREA...DROPPED HIGHS A BIT
NEAR THE EASTERN BORDER DUE TO LIKELY CLOUD COVER THROUGH MIDDAY.
WEAK LIFT MOVES IN BY FRIDAY...STILL PROBABLY A BIT STABLE BUT
I WILL ALLOW FOR SOME LATE DAY CONVECTION.
THE BIG EVENT IS THE UPPER TROUGH MOVING THROUGH THE WEST THIS
WEEKEND. MODELS CONTINUE TO SHOW SOME LARGE SCALE AGREEMENT...BUT
ARE QUITE DIFFERENT WITH THE DETAILS OF THE FLOW. LAST SEVERAL
RUNS OF THE GFS HAVE HAD A CLOSED LOW THAT TAKES 2-3 DAYS TO MOVE
FROM NORTHERN ARIZONA TO NORTHEASTERN COLORADO...DUMPING SEVERAL
INCHES OF PRECIPITATION ON THE NORTH SIDE OF THE LOW
TRACK...ESPECIALLY IN THE FRONT RANGE FOOTHILLS WHICH WOULD
PRODUCE SEVERAL FEET OF SNOW. ECMWF CONTINUES TO SPLIT THE ENERGY
IN THE TROUGH MORE. SOME OF THE ECMWF RUNS HAVE PRODUCED
SIGNIFICANT PRECIPITATION IN A SHORTER DURATION EVENT...BUT THE
CONSENSUS HAS BEEN TO HAVE THE SECONDARY JET STREAM SPLIT OFF THE
SOUTHERN PART OF THE TROUGH WHILE THE NORTHERN PART PASSES OVER
COLORADO SATURDAY NIGHT...WITH THE SOUTHERN PART BEING SLOWER AND
PRETTY FAR SOUTH TO HAVE MUCH AFFECT ON NORTHERN COLORADO. THE
SLOWNESS OF THE GFS SEEMS EXTREME GIVEN A LARGER SCALE PATTERN
WITHOUT DOWNSTREAM BLOCKING...THE SECOND PIECE OF ENERGY SHOULD
PRODUCE SOME SPLITTING OR WOBBLING OF THE LOW. CANNOT DISCOUNT
SOME KIND OF WOBBLY LOW BUT WE WILL CONTINUE TO DISCOUNT WHAT
SEEMS LIKE THE UNLIKELY GFS SOLUTIONS THAT KEEP US IN THE RIGHT
SPOT FOR HEAVY PRECIPITATION FOR 60 HOURS. ESRL/PSD REANALYSIS
PROBABILITIES SUPPORT THIS IDEA WITH ONLY LOW CHANCES OF HEAVY
PRECIPITATION...BUT PRETTY HIGH PROBABILITIES OF A FEW TENTHS OF
AN INCH. THE ECMWF SOLUTIONS WOULD HAVE A QUICK SHOT OF
PRECIPITATION SATURDAY INTO EARLY SUNDAY...THEN LITTLE OR NOTHING
AFTER THAT. WITH A HIGH LIKELIHOOD OF A CLOSED LOW TO THE
SOUTH...WOULD STILL GIVE HEED TO THE CHANCE OF ANOTHER ROUND OF
PRECIPITATION THAT COULD LAST A WHILE. EVEN THESE SOLUTIONS COULD
GIVE A SUBSTANTIAL AMOUNT OF PRECIPITATION OVER A LONG TIME. AS
FOR TEMPERATURES...PRETTY WARM FOR MUCH SNOW IN DENVER. MODEL
TEMPERATURES WOULD SUGGEST THE RAIN/SNOW LINE SOMEWHERE AROUND 5-6
THOUSAND FEET WHICH COULD LESSEN THE IMPACT OF ANY SNOW WITH
A WARM GROUND AND AIR TEMPERATURES NEAR OR ABOVE FREEZING THROUGH
MUCH OF THIS TIME.
BOTTOM LINE...FOR NOW NOT MUCH CHANGE IN THE FORECAST...WILL RAISE
THE POPS A BIT ESPECIALLY SATURDAY INTO EARLY SUNDAY WHICH IS THE
MOST LIKELY TIME.
&&
.AVIATION...SOUTHEAST WIND TO GRADUALLY DECREASE...BECOMING
SOUTHERLY AS DRAINAGE PATTERN DEVELOPS. LOW LEVEL MOISTURE TO
INCREASE AFTER MIDNIGHT...ALLOWING FOR LOW CLOUDS AND FOG TO
DEVELOP AS WELL AS SOME DRIZZLE. COULD SEE IFR CONDITIONS FROM
10Z-15Z AT AREA AIRPORTS...AFFECTING MAINLY DIA. CHANCE FOR STORMS
AFTER 18Z...MAINLY ALONG FOOTHILLS AND PALMER DIVIDE AS WELL AS
AREAS EAST AND SOUTHEAST OF DENVER. WILL HOLD OFF INCLUDING IN
TAFS FOR NOW. POTENTIAL FOR OUTFLOW BOUNDARIES FROM THOSE STORMS
AFFECTING THE AREA AIRPORTS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING FROM NOON TO 8 PM MDT WEDNESDAY FOR COZ211-213-
214.
&&
$$
SHORT TERM...D-L
LONG TERM....GIMMESTAD
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1017 AM MDT TUE APR 10 2012
.UPDATE...LOW CLOUDS AND FOG STILL HOLDING ON ACROSS WELD COUNTY
AS WELL AS ALONG PALMER DIVIDE AND FAR NORTHEAST CORNER...THOUGH
HAS BEEN GRADUALLY DISSIPATING IN THE PAST HOUR OR SO. SHOULD NOT
BE AN ISSUE FOR THE REST OF THE MORNING. OVERALL...CURRENT
FORECASTS LOOK ON TRACK...WITH MINOR TWEAKS TO SKY GRIDS. HIGH
TEMPERATURES LOOK OKAY. STILL THE SLIGHT CHANCE FOR STORMS THIS
AFTERNOON EAST OF THE CONTINENTAL DIVIDE INTO THE FOOTHILLS AND
URBAN CORRIDOR. RUC STILL SHOWING FAVORABLE LAPSE RATES ALONG WITH
CAPES FROM 500 TO ROUGHLY 1000 J/KG. FORECAST SOUNDINGS SHOWING
POTENTIAL FOR MORE WIND THAN RAIN...WILL NEED TO WATCH OUT FOR
GUSTY OUTFLOW WIND ALONG WITH THE LIGHTNING. STILL LOOKING TOO
STABLE EAST OF A FORT MORGAN TO LIMON LINE FOR ANY CONVECTION.
CHANCE FOR LOW CLOUDS AND FOG AGAIN OVERNIGHT ACROSS THE EASTERN
PLAINS...WITH PERHAPS DRIZZLE OR EVEN LIGHT RAIN SHOWERS.
&&
.AVIATION...FOG ACROSS WELD COUNTY ON THE DECREASE...WILL NOT BE
A THREAT TO THE AREA AIRPORTS. WINDS TO GRADUALLY SHIFT TO THE
SOUTHEAST DURING THE AFTERNOON...COULD BRIEFLY SEE GUSTS AROUND
15-18 KTS FROM 21Z-00Z. STILL A SLIGHT CHANCE FOR STORMS LATE THIS
AFTERNOON...MAINLY ALONG FOOTHILLS...PALMER DIVIDE AND AREAS EAST
OF THE DENVER AREA. CLOSE ENOUGH TO KEEP THE VCTS IN THE TAFS.
POTENTIAL FOR GUSTY OUTFLOW WINDS AFFECTING THE AIRPORTS...BUT
WILL HOLD OFF ON INCLUDING IN THE TAFS AT THIS TIME. BETTER CHANCE
FOR LOW CLOUDS AND FOG OVERNIGHT AS LOW LEVEL MOISTURE EXPECTED TO
WRAP BACK INTO THE NORTHERN SECTIONS OF THE DENVER AREA. WILL
MAINTAIN THE CURRENT TAF TRENDS FOR TONIGHT. OVERALL...ONGOING
TAFS LOOK REASONABLE.
&&
.PREV DISCUSSION... /ISSUED 337 AM MDT TUE APR 10 2012/
SHORT TERM...AN UPPER LEVEL RIDGE WILL CONTINUE OVER THE AREA
THRU TONIGHT. MEANWHILE AT THE SFC LOW PRES WILL RESIDE OVER WRN
CO AS SFC HIGH PRES CONTINUES OVER THE CNTRL PLAINS. THIS WILL
LEAVE SELY LOW LEVEL FLOW ACROSS NERN CO. CURRENTLY A WK DENVER
CYCLONE IS OVER SRN WELD COUNTY BUT BY AFTN IT MAY REDEVELOP
FURTHER SOUTH OVER DOUGLAS COUNTY WITH A WK CONVERGENCE FM JUST
EAST OF DENVER SOUTH TO THE PALMER DIVIDE. SOUNDINGS SHOW AFTN
CAPES RANGING FM 500-1000 ALONG THIS CONVERGENCE ZONE SO COULD SEE
SOME WDLY SCT TSTMS DVLP BY LATE AFTN ALONG THE BNDRY. APPEARS ERN
EXTENT OF CONVECTION WILL BE WEST OF A FORT MORGAN TO LIMON LINE
SO WILL NOT HAVE ANY POPS OVER THE FAR NERN PLAINS AS AIRMASS WILL
BE QUITE STABLE. MEANWHILE LOW LEVEL MOISTURE WILL BE A LITTLE
BETTER EAST OF THE DIVIDE SO COULD SEE A FEW HIGHER BASED STORMS
AS WELL BY LATE AFTN INTO THE EARLY EVENING HOURS DUE TO
FAVORABLE LAPSE RATES. HIGHS THIS AFTN OVER NERN CO WILL BE
AFFECTED BY LINGERING LOW CLOUDS AS READINGS OVER THE FAR NERN
PLAINS WILL NOT GET OUT OF THE LOWER TO MID 60S. MEANWHILE CLOSER
TO THE FRONT RANGE HIGHS WILL BE IN THE 70-75 RANGE WITH THE
WARMER READINGS NEAR DENVER.
FOR TONIGHT STRATUS AND FOG WILL REDEVELOP OVER NERN CO BY
MIDNIGHT AND MAY SPREAD BACK INTO THE URBAN CORRIDOR AS WELL.
COULD ALSO SEE SOME LIGHT SHOWERS/DRIZZLE AS WELL AFTER MIDNIGHT
IN SOME AREAS ESPECIALLY OVER THE NERN PLAINS.
LONG TERM...MODELS PERSIST WITH THE IDEA OF LOW LEVEL MOISTURE
PUSHING ACROSS THE THE PLAINS AS THE UPPER RIDGE SLIDES EAST OF
US AND GIVES WAY TO INCREASING SOUTHWESTERLY FLOW ALOFT. MODEL
SOUNDINGS FOR WEDNESDAY AFTERNOON SHOW QUITE A BIT OF LOW LEVEL
STABILITY TO THE EAST AND NORTHEAST OF DENVER. BUT...SHOWERS AND
THUNDERSTORMS THAT DEVELOP OVER THE I-25 CORRIDOR WEDNESDAY
AFTERNOON WILL HAVE THE ABILITY TO SPREAD OUTFLOW BOUNDARIES
EASTWARD WHICH MAY BE STRONG ENOUGH TO KICK OFF SOME ELEVATED
CONVECTION LATER IN THE AFTERNOON. ABOUT THE ONLY CHANGE I MADE TO
THE PREVIOUS FORECAST PACKAGE WAS TO ADD AREAS OF FOG ACROSS
NORTHEASTERN COLORADO TOMORROW MORNING.
A DEEP UPPER LOW MOVING OFF THE NORTHWESTERN U.S. COAST WILL
DRIVE FALLING HEIGHTS ACROSS THE WESTERN THIRD OF THE COUNTRY
THROUGH THE END OF THE WEEK. THE STRONGER WESTERLY FLOW ALOFT WILL
INITIALLY PUSH THE LOW LEVEL MOISTURE OUT OF THE STATE BUT THEN
BEGIN INCREASING MOISTURE AND INSTABILITY OVER THE MOUNTAINS FROM
THURSDAY AFTERNOON THROUGH THE WEEKEND. OVER THE WEEKEND...MODELS
SHOW A BROAD UPPER LOW OVER THE GREAT BASIN AND CENTRAL ROCKIES.
THIS WILL BRING UNSETTLED AND COOLER WEATHER ACROSS THE STATE.
DETAILS OF HOW THE UPPER LOW IS GOING TO EVOLVE AS IT CROSSES
THE STATE ARE HARD TO PICK OUT OF THE VARIOUS MODEL SOLUTIONS...
SO FOR NOW WILL STICK WITH A GRADUAL COOLING TREND AND A SLIGHT
CHANCE OF SHOWERS FROM DAY 4 ONWARD.
AVIATION...TRICKY FCST THIS MORNING AS WK DENVER CYCLONE IS OVER
SRN WELD COUNTY. LIFR CONDITIONS OVER THE NERN PLAINS WILL LIKELY
WRAP AROUND THIS FEATURE TOWARDS SUNRISE. CURRENT HRRR AND RCU
KEEP THIS STRATUS/FOG JUST NORTH OF DIA THRU MID MORNING HOWEVER
IF SFC WINDS BECOME LIGHT NWLY SOME OF THIS STRATUS/FOG COULD
AFFECT THE AIRPORT. IF IT DOES ROLL IN CEILINGS COULD EASILY DROP
BLO 500 FT WITH VISBILITIES DROPPING BLO 1/2 MILE FOR A FEW HOURS.
THUS WILL MENTION A TEMPO GROUP IN THE NEXT TAF FOR THE 12Z-15Z
TIME PERIOD.
BY AFTN LOOKS LIKE THE WK CYCLONE WILL REDEVELOP OVER DOUGLAS
COUNTY WITH SFC WINDS BECOMING MORE ENE. AS MENTIONED ABV THERE
WILL BE A WK CONVERGENCE ZONE SETTING UP JUST TO THE EAST AND SE
OF THE AIRPORT SO COULD SEE A FEW TSTMS DVLP ALONG THIS BNDRY
AFTER 21Z THRU 01Z SO WILL MENTION VCTS IN THE TAF. OVERNIGHT
LOOKS LIKE A SFC LOW WILL DVLP JUST EAST OF THE AIRPORT WITH
STRATUS AND FOG AFFECTING THE AREA FM 09Z-15Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....DANKERS
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
337 AM MDT TUE APR 10 2012
.SHORT TERM...AN UPPER LEVEL RIDGE WILL CONTINUE OVER THE AREA
THRU TONIGHT. MEANWHILE AT THE SFC LOW PRES WILL RESIDE OVER WRN
CO AS SFC HIGH PRES CONTINUES OVER THE CNTRL PLAINS. THIS WILL
LEAVE SELY LOW LEVEL FLOW ACROSS NERN CO. CURRENTLY A WK DENVER
CYCLONE IS OVER SRN WELD COUNTY BUT BY AFTN IT MAY REDEVELOP
FURTHER SOUTH OVER DOUGLAS COUNTY WITH A WK CONVERGENCE FM JUST
EAST OF DENVER SOUTH TO THE PALMER DIVIDE. SOUNDINGS SHOW AFTN
CAPES RANGING FM 500-1000 ALONG THIS CONVERGENCE ZONE SO COULD SEE
SOME WDLY SCT TSTMS DVLP BY LATE AFTN ALONG THE BNDRY. APPEARS ERN
EXTENT OF CONVECTION WILL BE WEST OF A FORT MORGAN TO LIMON LINE
SO WILL NOT HAVE ANY POPS OVER THE FAR NERN PLAINS AS AIRMASS WILL
BE QUITE STABLE. MEANWHILE LOW LEVEL MOISTURE WILL BE A LITTLE
BETTER EAST OF THE DIVIDE SO COULD SEE A FEW HIGHER BASED STORMS
AS WELL BY LATE AFTN INTO THE EARLY EVENING HOURS DUE TO
FAVORABLE LAPSE RATES. HIGHS THIS AFTN OVER NERN CO WILL BE
AFFECTED BY LINGERING LOW CLOUDS AS READINGS OVER THE FAR NERN
PLAINS WILL NOT GET OUT OF THE LOWER TO MID 60S. MEANWHILE CLOSER
TO THE FRONT RANGE HIGHS WILL BE IN THE 70-75 RANGE WITH THE
WARMER READINGS NEAR DENVER.
FOR TONIGHT STRATUS AND FOG WILL REDEVELOP OVER NERN CO BY
MIDNIGHT AND MAY SPREAD BACK INTO THE URBAN CORRIDOR AS WELL.
COULD ALSO SEE SOME LIGHT SHOWERS/DRIZZLE AS WELL AFTER MIDNIGHT
IN SOME AREAS ESPECIALLY OVER THE NERN PLAINS.
.LONG TERM...MODELS PERSIST WITH THE IDEA OF LOW LEVEL MOISTURE
PUSHING ACROSS THE THE PLAINS AS THE UPPER RIDGE SLIDES EAST OF
US AND GIVES WAY TO INCREASING SOUTHWESTERLY FLOW ALOFT. MODEL
SOUNDINGS FOR WEDNESDAY AFTERNOON SHOW QUITE A BIT OF LOW LEVEL
STABILITY TO THE EAST AND NORTHEAST OF DENVER. BUT...SHOWERS AND
THUNDERSTORMS THAT DEVELOP OVER THE I-25 CORRIDOR WEDNESDAY
AFTERNOON WILL HAVE THE ABILITY TO SPREAD OUTFLOW BOUNDARIES
EASTWARD WHICH MAY BE STRONG ENOUGH TO KICK OFF SOME ELEVATED
CONVECTION LATER IN THE AFTERNOON. ABOUT THE ONLY CHANGE I MADE TO
THE PREVIOUS FORECAST PACKAGE WAS TO ADD AREAS OF FOG ACROSS
NORTHEASTERN COLORADO TOMORROW MORNING.
A DEEP UPPER LOW MOVING OFF THE NORTHWESTERN U.S. COAST WILL
DRIVE FALLING HEIGHTS ACROSS THE WESTERN THIRD OF THE COUNTRY
THROUGH THE END OF THE WEEK. THE STRONGER WESTERLY FLOW ALOFT WILL
INITIALLY PUSH THE LOW LEVEL MOISTURE OUT OF THE STATE BUT THEN
BEGIN INCREASING MOISTURE AND INSTABILITY OVER THE MOUNTAINS FROM
THURSDAY AFTERNOON THROUGH THE WEEKEND. OVER THE WEEKEND...MODELS
SHOW A BROAD UPPER LOW OVER THE GREAT BASIN AND CENTRAL ROCKIES.
THIS WILL BRING UNSETTLED AND COOLER WEATHER ACROSS THE STATE.
DETAILS OF HOW THE UPPER LOW IS GOING TO EVOLVE AS IT CROSSES
THE STATE ARE HARD TO PICK OUT OF THE VARIOUS MODEL SOLUTIONS...
SO FOR NOW WILL STICK WITH A GRADUAL COOLING TREND AND A SLIGHT
CHANCE OF SHOWERS FROM DAY 4 ONWARD.
&&
.AVIATION...TRICKY FCST THIS MORNING AS WK DENVER CYCLONE IS OVER
SRN WELD COUNTY. LIFR CONDITIONS OVER THE NERN PLAINS WILL LIKELY
WRAP AROUND THIS FEATURE TOWARDS SUNRISE. CURRENT HRRR AND RCU
KEEP THIS STRATUS/FOG JUST NORTH OF DIA THRU MID MORNING HOWEVER
IF SFC WINDS BECOME LIGHT NWLY SOME OF THIS STRATUS/FOG COULD
AFFECT THE AIRPORT. IF IT DOES ROLL IN CEILINGS COULD EASILY DROP
BLO 500 FT WITH VISBILITIES DROPPING BLO 1/2 MILE FOR A FEW HOURS.
THUS WILL MENTION A TEMPO GROUP IN THE NEXT TAF FOR THE 12Z-15Z
TIME PERIOD.
BY AFTN LOOKS LIKE THE WK CYCLONE WILL REDEVELOP OVER DOUGLAS
COUNTY WITH SFC WINDS BECOMING MORE ENE. AS MENTIONED ABV THERE
WILL BE A WK CONVERGENCE ZONE SETTING UP JUST TO THE EAST AND SE
OF THE AIRPORT SO COULD SEE A FEW TSTMS DVLP ALONG THIS BNDRY
AFTER 21Z THRU 01Z SO WILL MENTION VCTS IN THE TAF. OVERNIGHT
LOOKS LIKE A SFC LOW WILL DVLP JUST EAST OF THE AIRPORT WITH
STRATUS AND FOG AFFECTING THE AREA FM 09Z-15Z.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...RPK
LONG TERM....DANKERS
AVIATION...RPK
AREA FORECAST DISCUSSION
NWS MIAMI FL
934 PM EDT WED APR 11 2012
.UPDATE...DRY AND TRANQUIL CONDITIONS ARE EXPECTED OVERNIGHT AS A
STABLE AIR MASS REMAINS IN PLACE. AS THE LOW LEVELS DECOUPLE
OVERNIGHT, WEAK DRAINAGE FLOW WILL DEVELOP. OVERALL, THE SHORT
TERM FORECAST IS ON TRACK WITH JUST MINOR TWEAKS TO THE HOURLY
GRIDS TO BETTER REFLECT THE LATEST TRENDS.
&&
.PREV DISCUSSION... /ISSUED 726 PM EDT WED APR 11 2012/
AVIATION...
VFR CONDITIONS EXPECTED THROUGH THE END OF THE TAF PERIOD. SEA
BREEZE MOVED INLAND ACROSS ALL BUT KPBI THIS AFTERNOON. A LIGHT
SOUTH TO SOUTHEAST FLOW WILL CONTINUE FOR AN HOUR OR SO AT MOST OF
THE EAST COAST TAF SITES BEFORE A DRAINAGE FLOW DEVELOPS. A WEAK
COLD FRONT WILL MOVE INTO THE REGION LATE TONIGHT INTO THE DAY ON
THURSDAY...AND THE WINDS WILL SHIFT TO THE NORTHEAST...AND THEN
EAST IN THE AFTERNOON AS THE SEA BREEZE DEVELOPS. A BIT MORE LOW
LEVEL MOISTURE ON THURSDAY DUE TO THE WEAK FRONT MAY LEAD TO
ISOLATED SHOWERS OR THUNDERSTORMS DEVELOPING NEAR THE EAST COAST
TAF SITES THURSDAY AFTERNOON. SO ADDED VCSH AFTER 18Z FOR MOST OF
THE EAST COAST TAF SITES.
PREV DISCUSSION... /ISSUED 237 PM EDT WED APR 11 2012/
DISCUSSION...A MID/UPPER LEVEL TROUGH OVER FLORIDA WILL PULL OUT
AND BE REPLACED BY A RIDGE OVER THE WEEKEND AND INTO THE EARLY TO
MIDDLE PART OF NEXT WEEK. A WEAK SURFACE COLD FRONT NOW OVER NORTH
CENTRAL FLORIDA WILL MOVE DOWN THE STATE AND ACROSS SOUTH FL WHILE
BECOMING DIFFUSE ON THU-THU NIGHT. A SLIGHT INCREASE IN MOISTURE
ASSOCIATED WITH THIS WEAK FEATURE SHOULD ALLOW FOR ISOLATED
SHOWERS TO DEVELOP ACROSS THE INTERIOR AND EAST COAST ON
THURSDAY, ALONG WITH THE POTENTIAL FOR A FEW THUNDERSTORMS. THIS
AFTERNOON IT LOOKS LIKE THE LACK OF MOISTURE COULD INHIBIT SHOWER
AND POSSIBLE TSTORM DEVELOPMENT ALL TOGETHER. HOWEVER, KEPT THE
SLIGHT CHANCE POPS INTERIOR-EAST GIVEN THE CU FIELD ON SATELLITE
IMAGERY AND THE HRRR CONTINUING TO SHOW SOME DEVELOPMENT.
CONFIDENCE IN DEVELOPMENT IS LOW THIS AFTERNOON WITH MODERATE
CONFIDENCE FOR THURSDAY.
THE FRONTAL BOUNDARY WILL WEAKEN THU NIGHT-FRI...BUT JUST ENOUGH
MOISTURE MAY REMAIN ACROSS SOUTHEAST AREAS TO ALLOW FOR A FEW
SHOWERS TO MOVE ONSHORE THE ATLANTIC COAST ON AN INCREASING
NE WIND FLOW. SO ADDED A SLIGHT CHANCE OF SHOWERS FOR BROWARD
/MIAMI-DADE FRI.
A BUILDING RIDGE OVER THE WEEKEND AND INTO THE EARLY TO MIDDLE
PART OF NEXT WEEK WILL RESULT IN A TRANQUIL WEATHER REGIME. GFS
AND ECMWF ARE IN AGREEMENT ON THIS.
RIP CURRENTS WILL BECOME AN INCREASING CONCERN AT THE ATLANTIC
BEACHES THIS WEEKEND AND INTO NEXT WEEK DUE TO THE INCREASING
ONSHORE WIND FLOW.
SLIGHTLY COOLER TEMPS AND DEWPOINTS IN THE 50S OVER THE WEEKEND
WILL GRADUALLY INCREASE NEXT WEEK AS WINDS TURN SOUTHEAST.
MARINE...LOW WINDS/SEAS WILL CONTINUE UNTIL WINDS INCREASE BEHIND
THE FRONT ESPECIALLY THIS WEEKEND. THIS WILL LEAD TO INCREASE SEAS
ESPECIALLY IN THE GULF STREAM OVER THE WEEKEND. WINDS COULD
APPROACH SMALL CRAFT ADVISORY CONDITIONS IN THE ATLANTIC THIS
WEEKEND...NEAR 20 KT.
FIRE WEATHER...MIN RELATIVE HUMIDITIES BELOW 35 PERCENT WILL
OCCUR OVER GLADES, HENDRY, AND INLAND COLLIER COUNTIES THIS
AFTERNOON WHERE A FIRE DANGER STMT REMAINS IN EFFECT. RH`S WILL
MODIFY A BIT THU-FRI BUT STILL COULD FALL DOWN TO NEAR CRITICAL
LEVELS SO THIS WILL NEED TO BE MONITORED.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 65 82 65 81 / 10 20 20 10
FORT LAUDERDALE 69 83 69 82 / 10 20 20 20
MIAMI 68 84 68 82 / 10 20 20 20
NAPLES 64 85 63 84 / - 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
UPDATE...14/MJB
AREA FORECAST DISCUSSION
NWS MIAMI FL
726 PM EDT WED APR 11 2012
.AVIATION...
VFR CONDITIONS EXPECTED THROUGH THE END OF THE TAF PERIOD. SEA
BREEZE MOVED INLAND ACROSS ALL BUT KPBI THIS AFTERNOON. A LIGHT
SOUTH TO SOUTHEAST FLOW WILL CONTINUE FOR AN HOUR OR SO AT MOST OF
THE EAST COAST TAF SITES BEFORE A DRAINAGE FLOW DEVELOPS. A WEAK
COLD FRONT WILL MOVE INTO THE REGION LATE TONIGHT INTO THE DAY ON
THURSDAY...AND THE WINDS WILL SHIFT TO THE NORTHEAST...AND THEN
EAST IN THE AFTERNOON AS THE SEA BREEZE DEVELOPS. A BIT MORE LOW
LEVEL MOISTURE ON THURSDAY DUE TO THE WEAK FRONT MAY LEAD TO
ISOLATED SHOWERS OR THUNDERSTORMS DEVELOPING NEAR THE EAST COAST
TAF SITES THURSDAY AFTERNOON. SO ADDED VCSH AFTER 18Z FOR MOST OF
THE EAST COAST TAF SITES.
&&
.PREV DISCUSSION... /ISSUED 237 PM EDT WED APR 11 2012/
DISCUSSION...A MID/UPPER LEVEL TROUGH OVER FLORIDA WILL PULL OUT
AND BE REPLACED BY A RIDGE OVER THE WEEKEND AND INTO THE EARLY TO
MIDDLE PART OF NEXT WEEK. A WEAK SURFACE COLD FRONT NOW OVER NORTH
CENTRAL FLORIDA WILL MOVE DOWN THE STATE AND ACROSS SOUTH FL WHILE
BECOMING DIFFUSE ON THU-THU NIGHT. A SLIGHT INCREASE IN MOISTURE
ASSOCIATED WITH THIS WEAK FEATURE SHOULD ALLOW FOR ISOLATED
SHOWERS TO DEVELOP ACROSS THE INTERIOR AND EAST COAST ON
THURSDAY, ALONG WITH THE POTENTIAL FOR A FEW THUNDERSTORMS. THIS
AFTERNOON IT LOOKS LIKE THE LACK OF MOISTURE COULD INHIBIT SHOWER
AND POSSIBLE TSTORM DEVELOPMENT ALL TOGETHER. HOWEVER, KEPT THE
SLIGHT CHANCE POPS INTERIOR-EAST GIVEN THE CU FIELD ON SATELLITE
IMAGERY AND THE HRRR CONTINUING TO SHOW SOME DEVELOPMENT.
CONFIDENCE IN DEVELOPMENT IS LOW THIS AFTERNOON WITH MODERATE
CONFIDENCE FOR THURSDAY.
THE FRONTAL BOUNDARY WILL WEAKEN THU NIGHT-FRI...BUT JUST ENOUGH
MOISTURE MAY REMAIN ACROSS SOUTHEAST AREAS TO ALLOW FOR A FEW
SHOWERS TO MOVE ONSHORE THE ATLANTIC COAST ON AN INCREASING
NE WIND FLOW. SO ADDED A SLIGHT CHANCE OF SHOWERS FOR BROWARD
/MIAMI-DADE FRI.
A BUILDING RIDGE OVER THE WEEKEND AND INTO THE EARLY TO MIDDLE
PART OF NEXT WEEK WILL RESULT IN A TRANQUIL WEATHER REGIME. GFS
AND ECMWF ARE IN AGREEMENT ON THIS.
RIP CURRENTS WILL BECOME AN INCREASING CONCERN AT THE ATLANTIC
BEACHES THIS WEEKEND AND INTO NEXT WEEK DUE TO THE INCREASING
ONSHORE WIND FLOW.
SLIGHTLY COOLER TEMPS AND DEWPOINTS IN THE 50S OVER THE WEEKEND
WILL GRADUALLY INCREASE NEXT WEEK AS WINDS TURN SOUTHEAST.
MARINE...LOW WINDS/SEAS WILL CONTINUE UNTIL WINDS INCREASE BEHIND
THE FRONT ESPECIALLY THIS WEEKEND. THIS WILL LEAD TO INCREASE SEAS
ESPECIALLY IN THE GULF STREAM OVER THE WEEKEND. WINDS COULD
APPROACH SMALL CRAFT ADVISORY CONDITIONS IN THE ATLANTIC THIS
WEEKEND...NEAR 20 KT.
FIRE WEATHER...MIN RELATIVE HUMIDITIES BELOW 35 PERCENT WILL
OCCUR OVER GLADES, HENDRY, AND INLAND COLLIER COUNTIES THIS
AFTERNOON WHERE A FIRE DANGER STMT REMAINS IN EFFECT. RH`S WILL
MODIFY A BIT THU-FRI BUT STILL COULD FALL DOWN TO NEAR CRITICAL
LEVELS SO THIS WILL NEED TO BE MONITORED.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 65 82 65 81 / 10 20 20 10
FORT LAUDERDALE 69 83 69 82 / 10 20 20 20
MIAMI 68 84 68 82 / 10 20 20 20
NAPLES 64 85 63 84 / - 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...14/MJB
AVIATION/RADAR...84/AK
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
954 PM EDT WED APR 11 2012
...PATCHY FROST POSSIBLE WELL INLAND EARLY THURSDAY MORNING...
.SYNOPSIS...
COOL AND DRY HIGH PRESSURE WILL GRADUALLY BUILD INTO THE REGION
THROUGH THE LATTER PART OF THE WEEK. OVER THE WEEKEND...THE HIGH
WILL SLIDE OFF THE SOUTHEAST COAST AND REMAIN THERE THROUGH EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THE POTENTIAL FOR FROST IS THE PRIMARY CONCERN TONIGHT. MODELS
SHOW A SECONDARY SURGE OF COOLER AIR ADVECTING IN FROM THE NORTH
OVERNIGHT AS THE TAIL END OF A SHORTWAVE ROUNDING THE BASE OF THE
UPPER LOW SPINNING OVER THE NORTHEAST U.S. PIVOTS OFFSHORE. THIS
SURGE OF COOLER AIR WILL PUSH OVERNIGHT LOWS WELL INTO THE 30S
AWAY FROM THE BEACHES BY SUNRISE THURSDAY WITH LOWS DROPPING INTO
THE MID 30S WELL INLAND AND AWAY FROM LAKES MOULTRIE AND MARION.
LOCAL FROST TOOLS SUGGEST THERE MAY BE JUST ENOUGH MIXING IN THE
BOUNDARY LAYER TO PREVENT SIGNIFICANT FROST FORMATION AS
TEMPERATURES DROP BELOW 36 DEGREES...SO WILL CONTINUE TO HOLD OFF
ON THE ISSUANCE OF A FROST ADVISORY AND MENTION PATCHY FROST
ROUGHLY ALONG AND NORTH OF A MILLEN-SYLVANIA-CUMMINGS-WALTERBORO-
JEDBURG-SHULERVILLE LINE. THIS EXCLUDES AREAS DOWNWIND OF LAKES
MARION AND MOULTRIE...INCLUDING MONCKS CORNER...WHICH WILL BE MORE
HEAVILY INFLUENCED BY NORTH WINDS BLOWING OVER THE WARMER LAKE
WATERS.
TEMPERATURES HAVE FALLEN A LITTLE QUICKER THAN EXPECTED THIS
EVENING ACROSS INTERIOR SOUTHEAST GEORGIA WHERE FULL DECOUPLING
OF THE BOUNDARY LAYER HAS OCCURRED. ADJUSTED OVERNIGHT LOWS DOWN A
FEW DEGREES IN THIS AREA...BUT THERMAL DECLINE RATES SHOULD LEVEL
OFF A BIT LATE AS THE BOUNDARY LAYER RECOUPLES WITH THE ONSET OF
COLD AIR ADVECTION IN THE WAKE OF THE SECONDARY SURGE.
NORTHERLY WINDS COULD ALLOW THE LOW AT WATERFRONT PARK TO
APPROACH THE RECORD LOW OF 42 DEGREES SET IN 1942. THE LOW-LEVEL
WIND TRAJECTORY JUST BEFORE SUNRISE WILL BE CRITICAL AS A MORE
EASTERLY COMPONENT WILL ALLOW THE WARMER CHARLESTON HARBOR TO HAVE
A GREATER INFLUENCE ON THE LOW TEMPERATURE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
A DEEP LAYER RIDGE WILL CONTINUE TO BUILD ACROSS THE AREA FROM THE
WEST AS A STRONG UPPER LEVEL TROUGH AXIS MOVES EASTWARD INTO THE
ATLANTIC THROUGH THE PERIOD. TEMPERATURES WILL BE BELOW
NORMAL...ESPECIALLY MIN TEMPS FOR THURSDAY...AND FRIDAY THEN
MODERATING TO ABOVE NORMAL BY SATURDAY.
THURSDAY...MODERATELY STRONG HIGH PRESSURE...CENTERED OVER THE OH
RIVER VALLEY...WILL EXTEND ACROSS THE ENTIRE SE U.S.. AFTER A COLD
MORNING START...THE COLD ADVECTION SHOULD BE OVER BY EARLY IN THE
DAY. HOWEVER...MAX TEMPS STILL NOT EXPECTED TO GET OUT OF THE UPPER
60S NORTH TO LOWER 70S SOUTH WITH SUNNY SKIES AND LIGHT ENE WINDS.
THURSDAY NIGHT...A SURFACE HIGH PRESSURE RIDGE WILL BE RIGHT OVER
THE AREA WITH LIGHT TO CALM WINDS AND CLEAR SKIES. THIS WILL SETUP
VERY GOOD RADIATIONAL CONDITIONS...AND HAVE GONE A DEG OR TWO BELOW
LATEST GUIDANCE. NOT THINKING THERE WILL BE ANY WIDESPREAD FREEZING
TEMPERATURES INLAND...BUT THERE COULD BE SOME PATCHY TO SCATTERED
FROST WELL INLAND. THE FROST FORECAST WILL LARGELY DEPEND ON HOW
MUCH THE SURFACE TDS RECOVER OVERNIGHT. LATEST GUIDANCE...EVEN FOR
INLAND LOCATIONS...SHOWS TDS ABOVE FREEZING. GIVEN THE MARGINAL
NATURE AND UNCERTAINTY...HAVE NOT YET ADDED ANY FROST TO THE
FORECAST.
FRIDAY...MODELS ARE SHOWING A SHORTWAVE MOVING DOWN THE BACK SIDE OF
THE UPPER TROUGH OVER THE ATLANTIC IN THE MORNING...THEN IT MOVES
OFF THE MID ATLANTIC COAST WELL NORTH OF US BY AFTERNOON. THIS
FEATURE SEEMS TO REINFORCE THE SURFACE RIDGE...CENTERED OVER THE
NORTHERN AREA BY AFTERNOON. 850 MB TEMPS ARE A FEW DEGS WARMER...
THUS EXPECT MAX TEMPS TO REFLECT THIS WITH HIGHS IN THE LOWER 70S
AWAY FROM THE IMMEDIATE COAST. LIGHT NE WINDS WILL VEER TO ESE BY
LATE DAY...WHICH WILL HOLD TEMPS IN THE MID TO UPPER 60S RIGHT AT
THE SHORE.
FRIDAY NIGHT...THE SURFACE RIDGE WILL SHIFT TO ENE OF THE REGION
THROUGH THE NIGHT...WHICH WILL KEEP LOW LEVEL FLOW ESE. THIS WILL
MODERATE TEMPS...WITH LOWS GENERALLY IN THE 40S TO NEAR 50...WHICH
IS STILL BELOW NORMAL.
SATURDAY...THE MID AND UPPER LEVEL RIDGE AXIS WILL BE JUST WEST OF
THE REGION WITH THE SURFACE RIDGE CENTERED OFFSHORE. THIS WILL SETUP
A SE LOW LEVEL FLOW AND CONTINUED MODERATION OF TEMPERATURES. EXPECT
HIGHS TO BE A FEW DEGS ABOVE NORMAL...IN THE MID TO UPPER 70S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
FORECAST AGREEMENT IS PRETTY GOOD IN THE LONG TERM PERIOD. THE LARGE
UPPER RIDGE WILL STRENGTHEN ACROSS THE SOUTHEASTERN US THROUGH EARLY
NEXT WEEK. EVENTUALLY A CLOSED UPPER ANTICYCLONE WILL DEVELOP AND
SIT DIRECTLY OVER THE SOUTHEAST COAST. THE RIDGE WILL GRADUALLY
SHIFT EASTWARD THROUGH TUESDAY AND BEGIN TO GIVE WAY TO A TROF
APPROACHING FROM THE WEST FOR THE MID WEEK TIME PERIOD. THE SURFACE
HIGH WILL SETTLE OVER THE WESTERN ATLANTIC AND WILL SUPPORT A
DEVELOPING WARM SOUTHERLY RETURN FLOW INTO EARLY NEXT WEEK. WITH
HEIGHTS RISING UNDER THE RIDGE...TEMPS WILL MODERATE NICELY AND
UPPER 80S MAY EVENTUALLY COVER THE AREA FOR MONDAY AND TUESDAY. THE
FORECAST IS DRY AS IT LOOKS LIKE THE NEXT FRONT WILL NOT APPROACH
UNTIL THE WEDNESDAY TIME FRAME.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
VFR FOR THE NEXT 24 HOURS.
EXTENDED AVIATION OUTLOOK...THERE ARE NO CONCERNS.
&&
.MARINE...
INCOMING DATA CONTINUE TO SUPPORT SMALL CRAFT ADVISORY CONDITIONS
ALL LEGS OUTSIDE OF THE CHARLESTON HARBOR. THE LATEST RUC EVEN
SUGGESTS A PERIOD OF GALES COULD OCCUR EAST OF THE SAVANNAH RIVER
ENTRANCE LATER TONIGHT. NOT TOO CONFIDENT ON GALES IN THIS
PATTERN...BUT IT WILL HAVE TO BE WATCHED CAREFULLY OVERNIGHT. WILL
MAINTAIN 20-25 KT WITH GUSTS TO 30 KT WITH SEAS BUILDING 3-5 FT
OVERNIGHT...PEAKING 4-6 FT OVER THE GEORGIA OFFSHORE WATERS BY
SUNRISE THURSDAY.
MODERATE TO STRONG HIGH PRESSURE WILL BE CENTERED NORTHWEST OF THE
WATERS TO START OFF THURSDAY. THE PRESSURE GRADIENT WILL BE PINCHED
ENOUGH OVER THE SOUTHERN HALF OF THE WATERS TO SUSTAIN WINDS 15-20
KTS WITH SOME HIGHER GUSTS. RIGHT NOW...IT APPEARS THAT WINDS/SEAS
WILL REMAIN BELOW SCA LEVELS. HIGH PRESSURE WILL SETTLE OVER THE
REGION THURSDAY NIGHT THROUGH FRIDAY WITH LIGHT WINDS BECOMING
ONSHORE NEAR THE COAST DURING THE AFTERNOON. SATURDAY THROUGH
MONDAY...HIGH PRESSURE WILL BE MAINLY EAST OF THE REGION WITH SSE
LOW LEVEL FLOW OF 15 KTS OR LESS AND SEAS 4 FT OR LESS.
&&
.FIRE WEATHER...
LATEST GUIDANCE CONTINUES TO INDICATE THAT AFTERNOON MINIMUM RH
VALUES WILL BE 20-25 PERCENT OVER INTERIOR LOCATIONS FOR THURSDAY
AFTERNOON. A FIRE DANGER STATEMENT WILL BE ISSUED LATER TONIGHT
FOR MOST AREAS. LOW LEVEL MOISTURE AND TEMPERATURES GRADUALLY
INCREASE BY LATE WEEK AND THROUGH THE WEEKEND. NOT EXPECTING ANY
CRITICAL RH OR WIND ISSUES FRIDAY THROUGH THE WEEKEND.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THURSDAY FOR AMZ352.
SMALL CRAFT ADVISORY FROM 4 AM TO 5 PM EDT THURSDAY FOR AMZ374.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR AMZ350.
SMALL CRAFT ADVISORY FROM 4 AM TO 11 AM EDT THURSDAY FOR
AMZ354.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...RFM
LONG TERM...BSH
AVIATION...
MARINE...
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
503 PM CDT TUE APR 10 2012
.DISCUSSION...
343 PM CDT
SHORT TERM...TONIGHT AND WEDNESDAY...
HIGH PRESSURE WILL GRADUALLY BUILD INTO THE UPPER GREAT LAKES REGION
THROUGH WEDNESDAY NIGHT AS LOW PRESSURE OVER SOUTHERN QUEBEC AND THE
NORTHEAST STATES SHIFTS OFF THE EAST COAST. THE PRESSURE GRADIENT
WILL SLACKEN TOWARD WEDNESDAY AFTERNOON...SO THE MIXING UP TO 5000
FEET AND 850MB WILL NOT TAP INTO AS HIGH OF WINDS AS THE PAST COUPLE
OF DAYS. WIND GUSTS SHOULD DIMINISH TO AROUND 14 KNOTS BY WED
AFTERNOON.
1000-850MB WINDS WILL VEER NORTH TONIGHT AFTER 06Z WED. DURING THIS
TIME...THE DIFFERENCE BETWEEN THE 850MB TEMPS OF AROUND -5C AND LAKE
TEMPS AROUND 6C OVER SOUTHERN LAKE MICHIGAN SHOULD BE SUFFICIENT TO
KEEP LAKE CLOUDS IN THE EASTERN PORTIONS OF THE FORECAST AREA
TONIGHT. THIS MAY LIMIT THE COOLING...SO THERE IS SOME UNCERTAINTY
IN HOW LOW THE TEMPS WILL GET TONIGHT. HOWEVER...THE CURRENT TEMPS
ARE ONLY AROUND 40 NEAR THE LAKE AND WILL NOT HAVE THAT FAR TO FALL
TO FREEZING OVERNIGHT. OVERALL...INLAND TEMPS SHOULD GET DOWN TO THE
28 TO 30 DEGREE RANGE IN THE LOWER 30S IN THE LAKESHORE COUNTIES.
THEREFORE...EXPANDED THE FREEZE WARNING FOR THE WHOLE FORECAST AREA.
LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY...
HIGH PRESSURE WILL KEEP THINGS DRY THROUGH THE DAY THURSDAY.
FORECAST LOWS WEDNESDAY NIGHT WILL BE RIGHT AROUND FREEZING...SO
MORE FREEZE HEADLINES MAY EVENTUALLY BE NEEDED. WINDS WILL BE
LIGHTER...SO SHOULD SEE FROST MOST PLACES. A PLEASANT DAY THEN
EXPECTED THURSDAY...WITH MOSTLY SUNNY SKIES AND NEAR NORMAL HIGH
TEMPERATURES.
AN ACTIVE PATTERN THEN SETS UP FOR FRIDAY INTO EARLY NEXT WEEK.
SHOULD SEE WARM ADVECTION SHOWERS FRIDAY...WITH SOME THUNDER
POSSIBLE. SHOWERS AND STORMS THEN POSSIBLE SATURDAY RIGHT THROUGH
TUESDAY...AS A COUPLE LOWS MOVE ALONG BAROCLINIC ZONE SITTING
ACROSS THE AREA. LIKELY POPS FOR THE WEEKEND...WITH CHANCE POPS
THEN EARLY NEXT WEEK DUE TO UNCERTAINTY WITH TIMING/PLACEMENT OF
INDIVIDUAL IMPULSES.
ABOVE NORMAL TEMPS EXPECTED OVER THE WEEKEND...WITH THE FORECAST
AREA ON THE WARM SIDE OF THE BAROCLINIC ZONE. COOLER AIR SAGS
SOUTHWARD EARLY NEXT WEEK...WITH TEMPS EXPECTED TO FALL TO BELOW
NORMAL VALUES BY TUESDAY.
DDV
&&
.FIRE WEATHER...
1230 PM CDT
CRITICAL FIRE WEATHER CONDITIONS CONTINUE THROUGH LATE AFTERNOON.
THIS IS MAINLY DUE TO THE EXCEPTIONALLY LOW DEW POINTS HERE AND
UPSTREAM TO THE NORTHWEST. THIS WILL KEEP RELATIVE HUMIDITY TO
NEAR OR BELOW 25 PERCENT WITH HIGH CONFIDENCE IN THOSE AREAS SOUTH
OF INTERSTATE 80. ALSO AIDING IN THE CRITICAL CONDITIONS ARE THE
LOW FUEL MOISTURE LEVELS. SO WITH THE CONTINUED CONCERNS...RED
FLAG WARNING THROUGH LATE AFTERNOON ACROSS THE SOUTHERN PART OF
THE FORECAST AREA. TO THE NORTH...LOWER TEMPERATURES WILL KEEP
RELATIVE HUMIDITY MORE IN THE 25 TO 30 PERCENT RANGE.
MRC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* GUSTY WINDS THROUGH EARLY EVENING.
* WIND DIRECTION ON WEDNESDAY.
PAW
//DISCUSSION...UPDATED 18Z...
STILL HAVE CONCERNS REGARDING DEVELOPMENT OF LAKE BREEZE. MESONET
OBS AT 19Z SHOWED THAT WINDS IMMEDIATELY ALONG THE LAKE WERE
CONSISTENTLY FROM ABOUT 350-360 DEGREES...WHILE LOCATIONS FURTHER
INLAND WERE RANGING FROM 310-330 DEGREES. HOWEVER...ORD HAS
SHIFTED TO A MORE NORTHERLY DIRECTION /350/ DESPITE SURROUNDING
OBSERVATIONS OF 320-330. HRRR MODEL CONTINUES TO SHOW THE LAKE
BREEZE PUSHING SLOWLY WESTWARD BY 20-21Z THIS AFTERNOON...PASSING
OVER MDW BETWEEN 21-22Z. THE OBSERVATIONS OVER THE LAKE ARE NOT
SUPPORTIVE OF THE HRRR SOLUTION THROUGH 20Z...SO CONFIDENCE IN
LOWERING IN THE WINDS BECOMING NORTHEAST AT MDW OR ORD. WILL KEEP
A 350 WIND AT ORD...AND BRING MDW TO 350 BY 23Z. GUST-WISE...EXTENSIVE
CUMULUS DEVELOPMENT OVER MDW/ORD HAS HELPED KEEP GUSTS DOWN A
BIT...BUT THE REMAINING TAF SITES HAVE GUSTED TO 25-30 KNOTS WHERE
LESS CLOUD COVER ALLOWS FOR MORE MIXING. BY ABOUT 22-23Z...WILL
SEE THE GUSTINESS LOWER AND THEN END BY SUNSET...AND THE CLOUDS
SHOULD DISSIPATE AS WELL BY EARLY EVENING. EXPECT MAINLY CLEAR
SKIES OVERNIGHT AS A HIGH PRESSURE RIDGE BEGINS BUILDING IN FROM
THE NORTHWEST. AS THIS RIDGE SHIFTS EASTWARD ON WEDNESDAY...THE
NORTHWEST WIND FLOW WILL BECOME MORE NORTHERLY AT ALL TAF SITES BY
15-16Z...WITH DIRECTIONS TRENDING MORE TOWARD 010-030 DEGREES
AFTER MIDDAY...ESPECIALLY AT ORD/MDW AS THE AXIS OF THE HIGH
STARTS BUILDING INTO WISCONSIN/NORTHERN ILLINOIS.
SHIMON
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE IN WIND TREND THIS EVEING.
* MEDIUM CONFIDENCE IN WIND DIRECTION WEDNESDAY.
PAW
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
* WEDNESDAY NIGHT AND THURSDAY...VFR.
* FRIDAY...CHANCE OF SHRA. SLIGHT CHANCE OF TSRA.
* SATURDAY AND SUNDAY...CHANCE OF TSRA. POSSIBLE MVFR.
* MONDAY...CHANCE OF SHRA. POSSIBLE MVFR. CMS
&&
.MARINE...
343 PM CDT
STRONG NORTHWEST WINDS WILL CONTINUE ACROSS LAKE MICHIGAN THROUGH
TONIGHT AS LOW PRESSURE OVER SOUTHERN QUEBEC AND NEW ENGLAND
REMAINS NEARLY STATIONARY WHILE A LARGE AREA OF HIGH PRESSURE
EXTENDS FROM WESTERN HUDSON BAY SOUTH INTO THE NORTHERN PLAINS.
THE LOW WILL BEGIN TO WEAKEN AS IT MOVES EAST OVER THE ATLANTIC
WEDNESDAY...WHILE THE HIGH SLOWLY BUILDS EAST ACROSS ONTARIO AND
THE LAKES REGION. NORTHWEST WINDS WILL SLOWLY DIMINISH OVERNIGHT
INTO WEDNESDAY MORNING...AS THEY TURN MORE NORTHERLY. WINDS
DIMINISH RAPIDLY WEDNESDAY NIGHT AS THE HIGH SPREADS ACROSS THE
LAKE. COULD BE A FEW GUSTS TO LOW END GALES OVER THE NORTH END OF
THE LAKE THROUGH THIS EVENING...ESPECIALLY THROUGH THE ISLANDS BUT
NOT EXPECTING GALES TO BECOME PREVAILING OR FREQUENT AT THIS TIME.
THE HIGH WILL MOVE TO THE EAST COAST FRIDAY WITH AN ACTIVE
UNSETTLED PATTERN THIS WEEKEND WITH LOW PRESSURE AREAS MOVING
NORTHEAST ACROSS THE UPPER LAKES REGION AND VARIOUS COLD/WARM
FRONTS IMPACTING THE LAKE.
CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...RED FLAG WARNING...ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-ILZ032-
ILZ033-ILZ039 UNTIL 7 PM TUESDAY.
FREEZE WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...1 AM WEDNESDAY TO 8 AM
WEDNESDAY.
IN...FREEZE WARNING...INZ001-INZ002-INZ010-INZ011-INZ019...1 AM
WEDNESDAY TO 8 AM WEDNESDAY.
RED FLAG WARNING...INZ010-INZ011-INZ019 UNTIL 7 PM TUESDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
ISSUED BY NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI
343 PM CDT TUE APR 10 2012
.DISCUSSION...
343 PM CDT
SHORT TERM...TONIGHT AND WEDNESDAY...
HIGH PRESSURE WILL GRADUALLY BUILD INTO THE UPPER GREAT LAKES REGION
THROUGH WEDNESDAY NIGHT AS LOW PRESSURE OVER SOUTHERN QUEBEC AND THE
NORTHEAST STATES SHIFTS OFF THE EAST COAST. THE PRESSURE GRADIENT
WILL SLACKEN TOWARD WEDNESDAY AFTERNOON...SO THE MIXING UP TO 5000
FEET AND 850MB WILL NOT TAP INTO AS HIGH OF WINDS AS THE PAST COUPLE
OF DAYS. WIND GUSTS SHOULD DIMINISH TO AROUND 14 KNOTS BY WED
AFTERNOON.
1000-850MB WINDS WILL VEER NORTH TONIGHT AFTER 06Z WED. DURING THIS
TIME...THE DIFFERENCE BETWEEN THE 850MB TEMPS OF AROUND -5C AND LAKE
TEMPS AROUND 6C OVER SOUTHERN LAKE MICHIGAN SHOULD BE SUFFICIENT TO
KEEP LAKE CLOUDS IN THE EASTERN PORTIONS OF THE FORECAST AREA
TONIGHT. THIS MAY LIMIT THE COOLING...SO THERE IS SOME UNCERTAINTY
IN HOW LOW THE TEMPS WILL GET TONIGHT. HOWEVER...THE CURRENT TEMPS
ARE ONLY AROUND 40 NEAR THE LAKE AND WILL NOT HAVE THAT FAR TO FALL
TO FREEZING OVERNIGHT. OVERALL...INLAND TEMPS SHOULD GET DOWN TO THE
28 TO 30 DEGREE RANGE IN THE LOWER 30S IN THE LAKESHORE COUNTIES.
THEREFORE...EXPANDED THE FREEZE WARNING FOR THE WHOLE FORECAST AREA.
LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY...
HIGH PRESSURE WILL KEEP THINGS DRY THROUGH THE DAY THURSDAY.
FORECAST LOWS WEDNESDAY NIGHT WILL BE RIGHT AROUND FREEZING...SO
MORE FREEZE HEADLINES MAY EVENTUALLY BE NEEDED. WINDS WILL BE
LIGHTER...SO SHOULD SEE FROST MOST PLACES. A PLEASANT DAY THEN
EXPECTED THURSDAY...WITH MOSTLY SUNNY SKIES AND NEAR NORMAL HIGH
TEMPERATURES.
AN ACTIVE PATTERN THEN SETS UP FOR FRIDAY INTO EARLY NEXT WEEK.
SHOULD SEE WARM ADVECTION SHOWERS FRIDAY...WITH SOME THUNDER
POSSIBLE. SHOWERS AND STORMS THEN POSSIBLE SATURDAY RIGHT THROUGH
TUESDAY...AS A COUPLE LOWS MOVE ALONG BAROCLINIC ZONE SITTING
ACROSS THE AREA. LIKELY POPS FOR THE WEEKEND...WITH CHANCE POPS
THEN EARLY NEXT WEEK DUE TO UNCERTAINTY WITH TIMING/PLACEMENT OF
INDIVIDUAL IMPULSES.
ABOVE NORMAL TEMPS EXPECTED OVER THE WEEKEND...WITH THE FORECAST
AREA ON THE WARM SIDE OF THE BAROCLINIC ZONE. COOLER AIR SAGS
SOUTHWARD EARLY NEXT WEEK...WITH TEMPS EXPECTED TO FALL TO BELOW
NORMAL VALUES BY TUESDAY.
DDV
&&
.FIRE WEATHER...
1230 PM CDT
CRITICAL FIRE WEATHER CONDITIONS CONTINUE THROUGH LATE AFTERNOON.
THIS IS MAINLY DUE TO THE EXCEPTIONALLY LOW DEW POINTS HERE AND
UPSTREAM TO THE NORTHWEST. THIS WILL KEEP RELATIVE HUMIDITY TO
NEAR OR BELOW 25 PERCENT WITH HIGH CONFIDENCE IN THOSE AREAS SOUTH
OF INTERSTATE 80. ALSO AIDING IN THE CRITICAL CONDITIONS ARE THE
LOW FUEL MOISTURE LEVELS. SO WITH THE CONTINUED CONCERNS...RED
FLAG WARNING THROUGH LATE AFTERNOON ACROSS THE SOUTHERN PART OF
THE FORECAST AREA. TO THE NORTH...LOWER TEMPERATURES WILL KEEP
RELATIVE HUMIDITY MORE IN THE 25 TO 30 PERCENT RANGE.
MRC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* LOCATION OF LAKE BREEZE THIS AFTERNOON.
* GUSTY WINDS THROUGH EARLY EVENING.
* WIND DIRECTIONS ON WEDNESDAY.
SHIMON
//DISCUSSION...UPDATED 20Z...
STILL HAVE CONCERNS REGARDING DEVELOPMENT OF LAKE BREEZE. MESONET
OBS AT 19Z SHOWED THAT WINDS IMMEDIATELY ALONG THE LAKE WERE
CONSISTENTLY FROM ABOUT 350-360 DEGREES...WHILE LOCATIONS FURTHER
INLAND WERE RANGING FROM 310-330 DEGREES. HOWEVER...ORD HAS
SHIFTED TO A MORE NORTHERLY DIRECTION /350/ DESPITE SURROUNDING
OBSERVATIONS OF 320-330. HRRR MODEL CONTINUES TO SHOW THE LAKE
BREEZE PUSHING SLOWLY WESTWARD BY 20-21Z THIS AFTERNOON...PASSING
OVER MDW BETWEEN 21-22Z. THE OBSERVATIONS OVER THE LAKE ARE NOT
SUPPORTIVE OF THE HRRR SOLUTION THROUGH 20Z...SO CONFIDENCE IN
LOWERING IN THE WINDS BECOMING NORTHEAST AT MDW OR ORD. WILL KEEP
A 350 WIND AT ORD...AND BRING MDW TO 350 BY 23Z. GUST-WISE...EXTENSIVE
CUMULUS DEVELOPMENT OVER MDW/ORD HAS HELPED KEEP GUSTS DOWN A
BIT...BUT THE REMAINING TAF SITES HAVE GUSTED TO 25-30 KNOTS WHERE
LESS CLOUD COVER ALLOWS FOR MORE MIXING. BY ABOUT 22-23Z...WILL
SEE THE GUSTINESS LOWER AND THEN END BY SUNSET...AND THE CLOUDS
SHOULD DISSIPATE AS WELL BY EARLY EVENING. EXPECT MAINLY CLEAR
SKIES OVERNIGHT AS A HIGH PRESSURE RIDGE BEGINS BUILDING IN FROM
THE NORTHWEST. AS THIS RIDGE SHIFTS EASTWARD ON WEDNESDAY...THE
NORTHWEST WIND FLOW WILL BECOME MORE NORTHERLY AT ALL TAF SITES BY
15-16Z...WITH DIRECTIONS TRENDING MORE TOWARD 010-030 DEGREES
AFTER MIDDAY...ESPECIALLY AT ORD/MDW AS THE AXIS OF THE HIGH
STARTS BUILDING INTO WISCONSIN/NORTHERN ILLINOIS.
SHIMON
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE REGARDING WIND SPEEDS/GUSTS.
* LOW CONFIDENCE REGARDING LOCATION OF WIND SHIFT THIS AFTERNOON.
* MEDIUM CONFIDENCE REGARDING WIND DIRECTION ON WEDNESDAY.
SHIMON
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
* WEDNESDAY NIGHT AND THURSDAY...VFR.
* FRIDAY...CHANCE OF SHRA. SLIGHT CHANCE OF TSRA.
* SATURDAY AND SUNDAY...CHANCE OF TSRA. POSSIBLE MVFR.
* MONDAY...CHANCE OF SHRA. POSSIBLE MVFR. CMS
&&
.MARINE...
343 PM CDT
STRONG NORTHWEST WINDS WILL CONTINUE ACROSS LAKE MICHIGAN THROUGH
TONIGHT AS LOW PRESSURE OVER SOUTHERN QUEBEC AND NEW ENGLAND
REMAINS NEARLY STATIONARY WHILE A LARGE AREA OF HIGH PRESSURE
EXTENDS FROM WESTERN HUDSON BAY SOUTH INTO THE NORTHERN PLAINS.
THE LOW WILL BEGIN TO WEAKEN AS IT MOVES EAST OVER THE ATLANTIC
WEDNESDAY...WHILE THE HIGH SLOWLY BUILDS EAST ACROSS ONTARIO AND
THE LAKES REGION. NORTHWEST WINDS WILL SLOWLY DIMINISH OVERNIGHT
INTO WEDNESDAY MORNING...AS THEY TURN MORE NORTHERLY. WINDS
DIMINISH RAPIDLY WEDNESDAY NIGHT AS THE HIGH SPREADS ACROSS THE
LAKE. COULD BE A FEW GUSTS TO LOW END GALES OVER THE NORTH END OF
THE LAKE THROUGH THIS EVENING...ESPECIALLY THROUGH THE ISLANDS BUT
NOT EXPECTING GALES TO BECOME PREVAILING OR FREQUENT AT THIS TIME.
THE HIGH WILL MOVE TO THE EAST COAST FRIDAY WITH AN ACTIVE
UNSETTLED PATTERN THIS WEEKEND WITH LOW PRESSURE AREAS MOVING
NORTHEAST ACROSS THE UPPER LAKES REGION AND VARIOUS COLD/WARM
FRONTS IMPACTING THE LAKE.
CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...RED FLAG WARNING...ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-ILZ032-
ILZ033-ILZ039 UNTIL 7 PM TUESDAY.
FREEZE WARNING...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...1 AM WEDNESDAY TO 8 AM
WEDNESDAY.
IN...FREEZE WARNING...INZ001-INZ002-INZ010-INZ011-INZ019...1 AM
WEDNESDAY TO 8 AM WEDNESDAY.
RED FLAG WARNING...INZ010-INZ011-INZ019 UNTIL 7 PM TUESDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
ISSUED BY NATIONAL WEATHER SERVICE LINCOLN IL
300 PM CDT TUE APR 10 2012
.UPDATE...
1230 PM CDT
TIGHT PRESSURE GRADIENT BETWEEN LOW PRESSURE OVER THEN NORTHEAST
STATES AND HIGH PRESSURE DROPPING DOWN INTO THE NORTHERN PLAINS IS
CAUSING PERSISTENT NORTHEAST WINDS ACROSS THE FORECAST AREA. MIXING
DEEPER THAN 850MB TODAY IS ALLOWING FOR DEWPOINT TEMPERATURES TO
DROP INTO THE LOW TEENS...WITH EVEN A FEW SITES IN THE SINGLE
DIGITS. MIN RH VALUES WILL GENERALLY BE IN THE 20 PERCENT RANGE
SOUTH OF I-80 THIS AFTERNOON. WIND GUSTS GREATER THAN 30 KNOTS
HAVE ALREADY BEEN OBSERVED AT SEVERAL LOCATIONS DUE TO THE DEEP
MIXING. THEREFORE...GOING RED FLAG WARNING SEEMS SUFFICIENT.
STRATOCUMULUS CLOUDS DEVELOPED IN THE NORTHEAST FORECAST AREA THIS
MORNING AND CONTINUE TO DEVELOP IN THE NORTHWEST EARLY THIS
AFTERNOON. EXPECT THE CLOUDS TO GRADUALLY INCREASE ACROSS THE
CENTRAL FORECAST AREA THIS AFTERNOON AS THE CYCLONIC SIDE OF THE
VORT MAX MOVES ACROSS THE REGION. RUC CU-RULE SUPPORTS THE
EXPANSION OF CLOUDS.
WITH CONTINUED COLD AIR ADVECTION...NOT EXPECTING MAX TEMPS TO
EXCEED LOWER 50S IN THE SOUTH AND MID 40S IN THE NORTH.
MRC
//PREV DISCUSSION...
305 AM CDT
THE FORECAST CHALLENGES IN THE SHORT TERM ARE THE CONTINUED DRY
AND BREEZY CONDITIONS TODAY ALONG WITH FREEZING TEMPERATURE
THREATS TONIGHT AND WEDNESDAY NIGHT. THE LONG RANGE PATTERN
BECOMES MORE ACTIVE WITH THUNDER CHANCES THIS WEEKEND AND WILL
BECOME THE MAIN CHALLENGE AS THE WEEK PROGRESSES.
AN EXPANSIVE RETROGRADING UPPER LEVEL LOW IS DRAPED ACROSS QUEBEC
EARLY THIS MORNING. A WAVE EXTENDING WEST FROM THIS NEAR LAKE
WINNIPEG WILL SHIFT SOUTHEAST THROUGH TODAY...BRINGING CONTINUED
COLD AIR ADVECTION AT THE TOP OF THE DAYTIME MIXING LAYER /850-800
MB/. A STRONG NORTHWEST UPPER JET OVER THE AREA IS LEADING THIS
WAVE SOUTH AND AS THIS JET SHIFTS SOUTHEAST IT HAS BEEN DRAGGING
SOME STRATOCU WITH IT ON ITS CYCLONIC SIDE. THIS LOOKS TO EXPAND
INTO NORTHEAST IL AND NORTHWEST IN TODAY...LIKELY MORE SO THIS
AFTERNOON AND EVENING. TEMPERATURES AROUND SEVEN TO TEN DEGREES
BELOW NORMAL ARE EXPECTED...WHICH IS NOT A HUGE DEPARTURE BUT
RELATIVE TO HOW WARM IT HAS BEEN IN THE PAST MONTH IT WILL LIKELY
FEEL IT. IN FACT...TODAYS HIGHS AT ORD AND RFD LOOK TO BE IN THE
TOP THREE COOLEST DAYS OVER THE PAST MONTH...IF NOT THE COOLEST
HIGH SINCE MARCH 9TH.
DEW POINTS STAYED LOW OVERNIGHT INTO EARLY THIS MORNING WITH
PRIMARILY UPPER TEENS AND LOWER 20S AWAY FROM THE MARINE LAYER
INFLUENCE. PARCEL TRAJECTORIES TODAY CONTINUE TO INDICATE FLOW
FROM CENTRAL AND NORTHERN MN WHERE DEW POINTS HAVE BEEN IN THE
LOWER TO MID TEENS. GIVEN PROJECTED MIXING...SEEMS PLAUSIBLE TO
HAVE DEW POINTS INDEED IN THE MID TEENS AND HUMIDITY IN THE 20 TO
30 PERCENT RANGE THIS AFTERNOON. WINDS WILL AGAIN BE OFF TO THE
RACES THIS MORNING WITH THE BOUNDARY LAYER BEING WELL-MIXED JUST A
COUPLE HOURS AFTER SUNRISE. GUSTS OF 30 TO 35 MPH LOOK REASONABLE
FOR AREAS SOUTH OF INTERSTATE 80...WHICH ALSO CORRELATES IN AREA
TO THE LOWEST RELATIVE HUMIDITY FORECAST. SEE THE FIRE WEATHER
DISCUSSION BELOW FOR MORE INFORMATION.
THE AFOREMENTIONED WAVE OVER LAKE WINNIPEG THIS MORNING WILL DROP
SOUTH OVER THE AREA TONIGHT TURNING OUR LOW-LEVEL FLOW MORE TOWARD
DUE NORTH. THIS MAY AID IN SOME LAKE-INDUCED CLOUD COVER INTO
NORTHWEST IN...BUT THE PROJECTED SATURATED LAYER IS FAIRLY THIN.
THE CONTINUED POSSIBILITY OF SOME COLD AIR STRATOCU AND A WELL-
MIXED BOUNDARY LAYER LEADS TO UNCERTAINTY ON JUST HOW LOW
TEMPERATURES WILL GET AND FOR HOW MANY HOURS BELOW FREEZING. SO
HAVE A FREEZE WARNING IN THE WEST FOR TONIGHT WHERE CONFIDENCE IS
THE HIGHEST...AND WHERE CLOUDS ARE EXPECTED HAVE A WATCH AT THIS
TIME. FORECAST READINGS OF 28 OR LOWER FOR A HARD FREEZE ARE NOT
FORECAST TONIGHT AT THIS TIME.
MORE NORTHERLY FLOW ON WEDNESDAY SHOULD HELP TO BRING MORE OF A
MARINE LAYER INTO NORTHWEST INDIANA AND PORTIONS OF NORTHEAST IL.
WHILE IT MAY NOT BE A TRUE LAKE BREEZE...LAKE-INDUCED COOLING
KEEPING READINGS AT OR BELOW 50 DEGREES LOOK TO BE THE CASE FOR
THE LAKE BORDERING COUNTIES. THE PRESSURE GRADIENT BEGINS TO
SLACKEN ON WEDNESDAY AFTERNOON AS THE SURFACE HIGH EXPANDS
SOUTHEAST FROM THE UPPER PLAINS. BY EVENING THIS RIDGE WILL BE
DIRECTLY OVER THE AREA ALLOWING FOR CALM WINDS. GOOD RADIATIONAL
COOLING SHOULD OCCUR...EVEN WITH ONE LAST UPPER LEVEL SHORT WAVE
THAT LOOKS TO BE MOISTURE-STARVED MOVING OVER THE AREA. THIS SETUP
WILL ALLOW WEDNESDAY NIGHT TO LIKELY BE THE COOLEST NIGHT IN THIS
STRETCH FOR MOST COMMUNITIES. HAVE NOT ISSUED A HEADLINE AT THIS
TIME WITH THE FREEZING CONCERNS TONIGHT BEING FIRST. BUT ONE WILL
LIKELY BE NEEDED IN TIME. AT THE VERY LEAST...THE BOUNDARY LAYER
SETUP LOOKS VERY GOOD FOR FROST WEDNESDAY NIGHT IF WE STAY MAINLY
CLEAR.
A MORE AMPLIFIED PATTERN STILL IS ON TRACK TO ESTABLISH ITSELF BY
WEEKS END. TWO MAIN UPPER WAVES LOOK TO MOVE ONTO THE PACIFIC
SHORE LATE THIS WEEK TO ESTABLISH A LONG WAVE TROUGH COVERING MUCH
OF WESTERN NORTH AMERICA. AHEAD OF THIS...A PRONOUNCED SHORT WAVE
WILL MOVE FROM THE DESERT SOUTHWEST WEDNESDAY TO THE UPPER PLAINS
BY THURSDAY AND BEGIN BRINGING THE WARM AIR ADVECTION TOWARD THE
AREA. UPPER LEVEL HEIGHT RISES THOUGH STILL PREVAIL OVER THE OUR
AREA INTO THURSDAY EVENING...AND HAVE SINCE REMOVED MUCH OF THE
POPS WITH THE OVERALL SLOWER MORE AMPLIFIED PATTERN. DEEPER
MOISTURE ADVECTS INTO THE AREA THROUGH FRIDAY AND FRIDAY
NIGHT...WITH ONGOING CYCLOGENESIS ACROSS THE CENTRAL PLAINS. THE
MODELS ARE IN DECENT CONSISTENCY WITH EVOLUTION OF THIS TO THE
NORTHEAST SHIFTING THE COLD FRONT EAST TOWARD THE AREA. THE MODELS
JUST VARY IN SPEED WITH THE EC BEING THE SLOWER AND MORE FAVORED
SOLUTION. AS SUCH...THE TIMING OF THE LOW LIFTING NORTHEAST INTO MN
AND WI IS SATURDAY AFTERNOON AND NIGHT...WITH A STRONG AND
ANOMALOUS LOW-LEVEL JET FORECAST FOR SATURDAY NIGHT. HAVE LIKELY
CHANCES FOR SHOWERS AND STORMS OVER THE WESTERN AND NORTHERN
FORECAST AREA DURING THAT PERIOD.
THE BOUNDARY WILL SHIFT SOUTH AND MAY BE SLOWER THAN THE PRESENTLY
FORECAST SUNDAY ARRIVAL. THE SLOWER THIS BOUNDARY MOVES THROUGH
THE GREATER THE POTENTIAL FOR AN ACTIVE START TO NEXT WEEK AS
WELL DUE TO THE BOUNDARY HANGING UP CLOSER TO THE AREA. WHILE IT
IS STILL SEVERAL DAYS OUT..THE INSTABILITY SHEAR SPECTRUM FAVORING
A CHANCE FOR STRONGER THUNDERSTORMS IS THERE FOR OUR AREA SATURDAY
NIGHT AND SUNDAY.
MTF
&&
.FIRE WEATHER...
1230 PM CDT
CRITICAL FIRE WEATHER CONDITIONS CONTINUE TODAY. THIS IS MAINLY
DUE TO THE EXCEPTIONALLY LOW DEW POINTS HERE AND UPSTREAM TO THE
NORTHWEST. THIS WILL KEEP RELATIVE HUMIDITY TO NEAR OR BELOW 25
PERCENT WITH HIGH CONFIDENCE IN THOSE AREAS SOUTH OF INTERSTATE
80. ALSO AIDING IN THE CRITICAL CONDITIONS ARE THE LOW FUEL
MOISTURE LEVELS. SO WITH THE CONTINUED CONCERNS...RED FLAG
WARNING FOR THIS AFTERNOON ACROSS THE SOUTHERN PART OF THE
FORECAST AREA. TO THE NORTH...LOWER TEMPERATURES WILL KEEP
RELATIVE HUMIDITY MORE IN THE 25 TO 30 PERCENT RANGE THIS
AFTERNOON.
MRC
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* LOCATION OF LAKE BREEZE THIS AFTERNOON.
* GUSTY WINDS THROUGH EARLY EVENING.
* WIND DIRECTIONS ON WEDNESDAY.
SHIMON
//DISCUSSION...UPDATED 20Z...
STILL HAVE CONCERNS REGARDING DEVELOPMENT OF LAKE BREEZE. MESONET
OBS AT 19Z SHOWED THAT WINDS IMMEDIATELY ALONG THE LAKE WERE
CONSISTENTLY FROM ABOUT 350-360 DEGREES...WHILE LOCATIONS FURTHER
INLAND WERE RANGING FROM 310-330 DEGREES. HOWEVER...ORD HAS
SHIFTED TO A MORE NORTHERLY DIRECTION /350/ DESPITE SURROUNDING
OBSERVATIONS OF 320-330. HRRR MODEL CONTINUES TO SHOW THE LAKE
BREEZE PUSHING SLOWLY WESTWARD BY 20-21Z THIS AFTERNOON...PASSING
OVER MDW BETWEEN 21-22Z. THE OBSERVATIONS OVER THE LAKE ARE NOT
SUPPORTIVE OF THE HRRR SOLUTION THROUGH 20Z...SO CONFIDENCE IN
LOWERING IN THE WINDS BECOMING NORTHEAST AT MDW OR ORD. WILL KEEP
A 350 WIND AT ORD...AND BRING MDW TO 350 BY 23Z. GUST-WISE...EXTENSIVE
CUMULUS DEVELOPMENT OVER MDW/ORD HAS HELPED KEEP GUSTS DOWN A
BIT...BUT THE REMAINING TAF SITES HAVE GUSTED TO 25-30 KNOTS WHERE
LESS CLOUD COVER ALLOWS FOR MORE MIXING. BY ABOUT 22-23Z...WILL
SEE THE GUSTINESS LOWER AND THEN END BY SUNSET...AND THE CLOUDS
SHOULD DISSIPATE AS WELL BY EARLY EVENING. EXPECT MAINLY CLEAR
SKIES OVERNIGHT AS A HIGH PRESSURE RIDGE BEGINS BUILDING IN FROM
THE NORTHWEST. AS THIS RIDGE SHIFTS EASTWARD ON WEDNESDAY...THE
NORTHWEST WIND FLOW WILL BECOME MORE NORTHERLY AT ALL TAF SITES BY
15-16Z...WITH DIRECTIONS TRENDING MORE TOWARD 010-030 DEGREES
AFTER MIDDAY...ESPECIALLY AT ORD/MDW AS THE AXIS OF THE HIGH
STARTS BUILDING INTO WISCONSIN/NORTHERN ILLINOIS.
SHIMON
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* HIGH CONFIDENCE REGARDING WIND SPEEDS/GUSTS.
* LOW CONFIDENCE REGARDING LOCATION OF WIND SHIFT THIS AFTERNOON.
* MEDIUM CONFIDENCE REGARDING WIND DIRECTION ON WEDNESDAY.
SHIMON
//OUTLOOK FOR ORD/MDW FOR 00Z THURSDAY-12Z TUESDAY...UPDATED 12Z...
* WEDNESDAY NIGHT AND THURSDAY...VFR.
* FRIDAY...CHANCE OF SHRA. SLIGHT CHANCE OF TSRA.
* SATURDAY AND SUNDAY...CHANCE OF TSRA. POSSIBLE MVFR.
* MONDAY...CHANCE OF SHRA. POSSIBLE MVFR. CMS
&&
.MARINE...
300 AM CDT
STRONG NORTHWEST WINDS WILL CONTINUE ACROSS LAKE MICHIGAN THROUGH
TONIGHT AS LOW PRESSURE OVER SOUTHERN QUEBEC AND NEW ENGLAND
REMAINS NEARLY STATIONARY WHILE A LARGE AREA OF HIGH PRESSURE
EXTENDS FROM WESTERN HUDSON BAY SOUTH INTO THE NORTHERN PLAINS.
THE LOW WILL BEGIN TO WEAKEN AS IT MOVES EAST OVER THE ATLANTIC
WEDNESDAY...WHILE THE HIGH SLOWLY BUILDS EAST ACROSS ONTARIO AND
THE LAKES REGION. NORTHWEST WINDS WILL SLOWLY DIMINISH OVERNIGHT
INTO WEDNESDAY MORNING...AS THEY TURN MORE NORTHERLY. WINDS
DIMINISH RAPIDLY WEDNESDAY NIGHT AS THE HIGH SPREADS ACROSS THE
LAKE. COULD BE A FEW GUSTS TO LOW END GALES OVER THE NORTH END OF
THE LAKE THROUGH THIS EVENING...ESPECIALLY THROUGH THE ISLANDS BUT
NOT EXPECTING GALES TO BECOME PREVAILING OR FREQUENT AT THIS TIME.
THE HIGH WILL MOVE TO THE EAST COAST FRIDAY WITH AN ACTIVE
UNSETTLED PATTERN THIS WEEKEND WITH LOW PRESSURE AREAS MOVING
NORTHEAST ACROSS THE UPPER LAKES REGION AND VARIOUS COLD/WARM
FRONTS IMPACTING THE LAKE. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...RED FLAG WARNING...ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-ILZ032-
ILZ033-ILZ039 UNTIL 7 PM TUESDAY.
FREEZE WARNING...ILZ003-ILZ004-ILZ008-ILZ010-ILZ011-ILZ019-
ILZ021-ILZ032-ILZ039...1 AM WEDNESDAY TO 8 AM WEDNESDAY.
FREEZE WATCH...ILZ005-ILZ006-ILZ012-ILZ013-ILZ014-ILZ020-ILZ022-
ILZ023-ILZ033...1 AM WEDNESDAY TO 8 AM WEDNESDAY.
IN...FREEZE WATCH...INZ001-INZ002-INZ010-INZ011-INZ019...1 AM
WEDNESDAY TO 8 AM WEDNESDAY.
RED FLAG WARNING...INZ010-INZ011-INZ019 UNTIL 7 PM TUESDAY.
LM...SMALL CRAFT ADVISORY...NEARSHORE WATERS
UNTIL 10 PM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1238 AM CDT TUE APR 10 2012
.DISCUSSION...
849 PM CDT
GOING FORECAST GENERALLY APPEARS TO BE IN GOOD SHAPE WITH JUST
SOME MINOR TWEAKS TO HOURLY GRIDS. COLD AIR STRATOCUMULUS OVER
WISCONSIN DOESNT SEEM TO BE IN ANY HURRY TO HEAD SOUTHWARD SO HAVE
SLOWED ITS ARRIVAL IN THE GRIDS AND BEGINNING TO HAVE MY DOUBTS IF
IT WILL EVEN REACH THE AREA TONIGHT.
THE 00Z UPPER AIR ANALYSIS SUGGESTS THAT SOME FAIRLY STRONG COLD
AIR ADVECTION WILL TAKE PLACE TONIGHT...SO DESPITE WINDS STAY UP
CAN NOT ARGUE WITH GOING FORECAST LOWS AND NOT PLANNING ANY
CHANGES TO TEMPS OR FREEZE HEADLINES.
IZZI
//PREV DISCUSSION...
257 PM CDT
SYNOPSIS...
SHORT TERM CONCERNS TODAY LIE WITH VERY DRY AND WINDY
CONDITIONS...SHIFTING TO THE POTENTIAL FREEZING TEMPERATURES
TONIGHT. A COOL DRY AIRMASS WILL BE OVER THE AREA THROUGH
MIDWEEK...AGAIN MAKING COLD OVERNIGHT TEMPERATURES A FOCUS. THEN THE
PATTERN WILL SHIFT TO A WARMER AND MUCH MORE ACTIVE ONE LATE IN THE
WEEK AND THROUGH THE WEEKEND...WITH PERIODS OF SHOWERS AND
THUNDERSTORMS POSSIBLE.
UPPER LEVEL PATTERN...
A LONG WAVE TROUGH WAS NOTED ON MID MORNING WATER VAPOR IMAGERY OVER
EASTERN NOAM...WITH A FEW CLOSED UPPER LOWS OVER SOUTHERN CANADA
EMBEDDED IN LARGE-SCALE TROUGH. AN UPPER LEVEL RIDGE WAS IN PLACE
OVER WESTERN NOAM...WITH THE RIDGE AXIS EXTENDING FROM THE DESERT
SOUTHWEST NORTH TO THE CANADIAN ROCKIES. A LARGE...DEEP UPPER TROUGH
WAS OFF THE WEST COAST. THE LONG WAVE TROUGH OVER EASTERN NOAM WILL
KEEP THE AREA IN COOL DRY NORTH TO NORTHWEST FLOW THROUGH MID
WEEK...BUT THEN THE WEST COAST TROUGH WILL FORCE THE RIDGE
EASTWARD...BRINGING A LATE WEEK WARM UP AND ALSO OPENING UP THE GULF
FOR MOISTURE TO FLOW NORTHWARD. THE DEEP WESTERN TROUGH WILL
CONTINUE TO SLOWLY PRESS EAST OVER THE WEEKEND...WITH ASSOCIATED
SURFACE LOW TRACKING NORTHEAST TOWARD THE GREAT LAKES REGION.
SHORT TERM...TODAY THROUGH THURSDAY
MAINLY SUNNY TODAY OTHER THAN A FEW DIURNALLY DRIVEN CU WITH VERY
DEEP MIXING UP NEAR 700 MB NOTED ON AIRCRAFT SOUNDINGS. THIS ENABLED
THE VERY DRY FIRE WEATHER CONDITIONS...AS WELL AS STRONGER WINDS
FROM ALOFT TO MIX DOWN...ALSO DUE TO TIGHT PRESSURE GRADIENT. SOME
AIRPORT OBS OCCASIONALLY REACHED WIND ADVISORY CRITERIA IN
GUSTS...BUT NOT FREQUENT ENOUGH TO PROMPT ISSUANCE OF A SHORT-FUSE
WIND ADVISORY. TEMPS ALOFT WERE SLOWLY COOLING...BUT DRY
CONDITIONS AND DRY ADIABATIC LAPSE RATES BROUGHT ANOTHER MILD DAY
TO THE CWA...WITH HIGHS IN THE LOW AND MID 60S. RED FLAG WARNING
SHOULD BE ABLE TO LEFT TO EXPIRE AT 00Z AS TEMPERATURES BEGIN TO
FALL.
TONIGHT...AS STRONG...COOL HIGH PRESSURE DROPS SOUTHEAST FROM THE
CANADIAN PRAIRIES AND NORTHERN PLAINS...PRESSURE GRADIENT WILL
REMAIN FAIRLY TIGHT...KEEPING WINDS GOING EVEN AS BOUNDARY LAYER
TRIES TO DECOUPLE. RUC HAD A PRETTY GOOD HANDLE ON CLOUD COVER OVER
UPPER MIDWEST AND NORTHWESTERN GREAT LAKES REGION...SO HAVE SOME
CLOUDS CLIPPING FAR NORTHEASTERN ILLINOIS AND NORTHWEST
INDIANA...FROM THIS EVENING THROUGH LATE TONIGHT. REMAINDER OF CWA
SHOULD STAY MOSTLY CLEAR. BEHIND A WEAK COLD FROPA...850 MB TEMPS
DROP TO WELL BELOW 0C LATE TONIGHT AND COLD LOW LEVEL AIR MASS WILL
RESULT IN TEMPERATURES QUICKLY DROPPING. WENT AHEAD AND HOISTED A
FREEZE WARNING FOR NORTHERN ILLINOIS MAINLY WEST OF THE FOX RIVER
VALLEY FROM LATE TONIGHT THROUGH EARLY TUESDAY MORNING...ADDING IN
KANE AND MCHENRY COUNTIES. NUDGED LOW TEMPERATURES TOWARD SLIGHTLY
WARMER MAV GUIDANCE...BUT DESPITE THIS AND WINDS BEING LIMITING
FACTOR TO HOW FAR TEMPERATURES FALL AND PRECLUDING FROST
DEVELOPMENT...STILL EXPECTING TO SEE SEVERAL HOURS IN THE UPPER 20S
TO NEAR FREEZING FOR THE WARNING AREA. FOR THE REMAINDER OF THE
CWA...EXPECTING LOW TO MID 30S...WITH UPPER 30S IN DOWNTOWN CHICAGO.
TUESDAY...WITH LARGE HIGH PRESSURE STILL TO OUR NORTHWEST...SLIGHTLY
WEAKER BUT STILL TIGHT PRESSURE GRADIENT WILL LEAD TO ANOTHER BREEZY
AND DRY DAY WITH DEEP MIXING TO OR ABOVE 800 MB. TEMPERATURES
SEVERAL DEGREES BELOW 0C AT H85 WILL TRANSLATE TO BELOW NORMAL HIGH
TEMPERATURES...IN THE UPPER 40S TO AROUND 50 NORTH AND LOW TO MID
50S SOUTH. THERE MAY BE SOME MORE STOUT DIURNAL CU OR STRATOCU
DEVELOPMENT BY MID TUESDAY AFTERNOON...ESPECIALLY FOR NE IL...AS
BUFKIT SOUNDINGS SHOWING A THIN LAYER CLOSE TO SATURATION AT TOP OF
MIXED LAYER.
WILL LIKELY NEED FREEZE HEADLINES FOR MUCH OF THE CWA TUESDAY
NIGHT...WITH COOL DRY AIR MASS OVERHEAD AND MOSTLY CLEAR SKIES. HAVE
LOWS AT OR BELOW FREEZING FOR ENTIRE AREA EXCEPT CHICAGO URBAN
CORE...WITH UPPER 20S IN THE COLDEST SPOTS. TO REDUCE
CONFUSION...KEEPING IT DAY BY DAY WITH FREEZE HEADLINES SO MIDNIGHT
SHIFT WILL LIKELY ISSUE A PRODUCT OVERNIGHT FOR TOMORROW NIGHT`S
EXPECTED FREEZING CONDITIONS. LOOKS LIKE ENOUGH PRESSURE GRADIENT TO
KEEP WINDS GOING...BUT A BETTER CHANCE TO DECOUPLE AS HIGH PRESSURE
MOVES CLOSER TO AREA. SHOULDNT BE MUCH WIDESPREAD FROST DEVELOPMENT.
SURFACE HIGH WILL MOVE OVERHEAD WEDNESDAY INTO WEDNESDAY
NIGHT...CONTINUING MOSTLY CLEAR SKIES. TEMPERATURES WILL WARM AWAY
FROM THE LAKE TO THE MID AND UPPER 50S DUE TO MODEST WARM
ADVECTION...BUT NORTHEAST FLOW WILL KEEP THE LAKEFRONT COOLER...IN
THE UPPER 40S TO AROUND 50 DEGREES. DESPITE WARMING ALOFT WEDNESDAY
NIGHT...IT LOOKS TO BE BEST RADIATIONAL COOLING SET-UP OF THE WEEK
WITH HIGH PRESSURE OVERHEAD AND BOUNDARY LAYER LIKELY TO
DECOUPLE...LEADING TO VERY LIGHT OR CALM WINDS. THUS WENT BELOW MAV
AND MET GUIDANCE AND FORECASTED LOWS AT OR BELOW FREEZING EVERYWHERE
EXCEPT IMMEDIATE CHICAGO AREA AGAIN. FREEZE HEADLINES CERTAINLY
POSSIBLE AGAIN WEDNESDAY NIGHT FOR A LARGE PORTION OF THE AREA.
SURFACE HIGH WILL SLOWLY SLIDE EAST ON THURSDAY...TURNING THE LIGHT
SYNOPTIC FLOW SOUTHEASTERLY. ALONG WITH RISING HEIGHTS AND
TEMPERATURES ALOFT...ADD ANOTHER COUPLE DEGREES TO FORECAST HIGHS
AWAY FROM THE LAKE...TOPPING OUT IN THE UPPER 50S NORTH AND LOW 60S
SOUTH. EAST-SOUTHEAST WINDS OR A LAKE BREEZE WILL KEEP THE ILLINOIS
LAKEFRONT COOLER...CURRENTLY EXPECTING LOW 50S. SKY WILL START OUT
SUNNY...WITH SOME HIGH CLOUDS GRADUALLY FILTERING IN DURING
AFTERNOON FROM SYSTEM WELL BACK TO OUR WEST.
RC
EXTENDED...THURSDAY NIGHT THROUGH TUESDAY
A TRANSITION TO A MILDER AND MORE ACTIVE WEATHER PATTERN IS NOTED
FOR THE END OF THE WEEK AND THE WEEKEND...THOUGH MODEL UNCERTAINTY
DOES INCREASE WITH TIMING AND DETAILS DURING THE PERIOD.
UPPER TROUGH ACROSS EASTERN NORTH AMERICA IS MOVING OFF TO THE EAST
BY THURSDAY NIGHT...WITH SURFACE HIGH PRESSURE RIDGE DRIFTING OFF
ACROSS THE GREAT LAKES TO OUR EAST. FARTHER WEST...BROAD UPPER
TROUGH IS DEPICTED OVER MUCH OF THE WESTERN CONUS WITH SURFACE
PRESSURE FALLS DEVELOPING ACROSS THE PLAINS IN RESPONSE TO UPPER JET
STREAK THAT EJECTS FROM THE DESERT SOUTHWEST. THIS RESULTS IN
DEVELOPMENT OF SOUTHEAST LOW LEVEL FLOW ACROSS THE FORECAST AREA...
WITH LOW LEVEL WARM ADVECTION DEVELOPING PARTICULARLY WEST OF THE
MISSISSIPPI VALLEY. ECMWF AND GEM ARE A LITTLE SLOWER THAN OUR
DOMESTIC MODELS WITH THE EASTWARD PROGRESSION OF THE UPPER RIDGE
AXIS AND THIS IS PREFERRED GIVEN HIGH AMPLITUDE OF THE PATTERN. DRY
LOW LEVEL AIR ASSOCIATED WITH RETREATING SURFACE HIGH SHOULD HELP TO
KEEP WARM ADVECTION PRECIPITATION AT BAY AS WELL...ESPECIALLY IN THE
EASTERN PARTS OF THE CWA AND HAVE THUS TRIMMED POPS THERE ALONG THE
LINES OF THE GEM WHICH IS BETWEEN THE DRY ECMWF AND MORE MOIST GFS
IN TERMS OF PRECIP COVERAGE BY FRIDAY MORNING.
PRECIPITATION CHANCES INCREASE FRIDAY AS UPPER RIDGE MOVES EAST AND
UPPER JET STREAK CONTINUES TO SPREAD NORTHEAST INTO THE MIDWEST.
GUIDANCE DIFFERS WITH DEGREE OF SURFACE LOW DEVELOPMENT ACROSS THE
PLAINS AND UPPER MIDWEST...THOUGH WEAK WAVE AND WARM FRONT SHOULD
DEVELOP INTO IOWA/MINNESOTA BY FRIDAY NIGHT PER GEM SOLUTION. THIS
WOULD SUPPORT SOLID CHANCE POPS WITH A FEW PERIODS OF ELEVATED
SHOWERS/THUNDERSTORMS POSSIBLE INTO SATURDAY...AS WARM FRONT LIFTS
NORTH ACROSS THE CWA. SECOND/STRONGER UPPER WAVE LIFTS OUT ACROSS
THE REGION SATURDAY NIGHT INTO SUNDAY...MAINTAINING SHOWER AND
THUNDERSTORM THREAT THROUGH THE WEEKEND.
BY SUNDAY...SIGNIFICANT DIFFERENCES ARE EVIDENT IN EVOLUTION OF
DETAILS OF SURFACE PATTERN AND TIMING OF COLD FRONTAL PASSAGE. GFS
IS STRONGER/MORE CLOSED WITH A STRONGER SURFACE LOW REFLECTION WITH
THE INITIAL WAVE FROM FRIDAY NIGHT/SATURDAY...WHICH RESULTS IN
SECOND LOW TAKING A MORE EAST/SOUTH TRACK ACROSS THE FORECAST AREA
EARLY SUNDAY. ECMWF...WITH A WEAKER SURFACE REFLECTION OF THE
INITIAL SHORT WAVE...HOLDS THE SECOND LOW OFF TO OUR NORTH/NORTHWEST
ON SUNDAY...WITH A LATER COLD FROPA SUNDAY AFTERNOON. CONTINUE TO
PREFER A MORE ECMWF-LIKE SOLUTION...RESULTING IN WARMER TEMPS DURING
THE DAY SUNDAY...AND A POTENTIALLY GREATER THREAT OF SEVERE
WEATHER LOCALLY. WIDE-OPEN FLOW OFF THE GULF OF MEXICO ALSO
SUGGESTS SOME POTENTIALLY FOR LOCALLY HEAVY CONVECTIVE RAINFALL
DURING THE SATURDAY-SUNDAY PERIOD...WITH 12Z GEFS INDICATING
PRECIPITABLE WATER VALUES RUNNING 2-3 STANDARD DEVIATIONS ABOVE
CLIMO.
FRONT SAGS SOUTH OF THE AREA SUNDAY NIGHT INTO EARLY NEXT
WEEK...KEEPING AN OVERRUNNING PRECIP THREAT POTENTIALLY
CLOSE WHILE COOLER/STABLE SURFACE AIR PREVAILS ACROSS THE CWA IN
NORTHERLY LOW LEVEL FLOW.
RATZER
&&
.FIRE WEATHER...
849 PM CDT
AS OF 8 PM WE STILL HAD A FEW OBSERVATION SITES MEETING RED FLAG
CRITERIA...BUT WITH CONDITIONS EXPECTED TO CONTINUE TO IMPROVE
OPTED TO GO AHEAD AND LET THE RED FLAG WARNING EXPIRE. APPEARS AS
THOUGH WE COULD FLIRT WITH RED FLAG CRITERIA AGAIN TUESDAY
AFTERNOON...HOWEVER WINDS ARE EXPECTED TO BE A BIT LIGHTER WITH
20FT SUSTAINED WINDS PROBABLY FALLING SHY OF THE 20 MPH CRITERIA.
IN ADDITION...RH SHOULD NOT BE AS LOW AS THE PAST COUPLE OF
AFTERNOON...THOUGH COULD STILL BOTTOM OUT IN THE 25-30 PERCENT
RANGE. WHILE THERE HAS BEEN A SIGNIFICANT GREEN UP THANKS TO THE
MARCH WARMTH...THE RECENT DRY SPELL HAS ALLOWED QUICKER DRYING
FUELS TO REALLY DRY OUT. HAVE OPTED TO HOLD OFF ON A FIRE WEATHER
WATCH FOR TUESDAY AT THIS TIME...BUT DID INCLUDE FIRE DANGER
WORDING IN HWO AND WILL UPDATE FWF SYNOPSIS TO INCLUDE THIS
POTENTIAL. WILL BRIEF OVERNIGHT SHIFT ON THE CONCERNS AND ALLOW
THEM TO MAKE FINAL CALL AFTER WATCHING RH RECOVERY OVERNIGHT AND
GETTING A LOOK AT 00Z MODEL GUIDANCE.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* GUSTY NORTHEAST WINDS THROUGH MID/LATE EVENING. CMS
//DISCUSSION...UPDATED 06Z...
MAIN FORECAST CONCERN REMAINS GUSTY NORTHEAST WINDS. A BOUNDARY/
WIND SHIFT...POSSIBLE LATE LAKE BREEZE...MOVED ACROSS NORTHEAST IL
WITHIN THE PAST FEW HRS SHIFTING WINDS TO THE NORTH/NORTHEAST. AS
THIS BOUNDARY MOVES FURTHER INLAND AND LIKELY DISSIPATES...WINDS
SHOULD SLOWLY SHIFT BACK TO THE NORTHWEST EARLY THIS MORNING.
COOLER TEMPS HAVE ALLOWED THE SURFACE TO DECOUPLE SO EXPECT WINDS
TO REMAIN IN THE 10-15KT RANGE WITH A FEW HIGHER GUSTS POSSIBLE
THROUGH SUNRISE. ONCE THE LOW LEVELS BEGIN TO MIX...BY MID
MORNING...WINDS SHOULD STEADILY INCREASE WITH GUSTS IN THE MID
20KT...PERHAPS UPPER 20KT RANGE BY MID/LATE MORNING. WINDS LIKELY
REMAIN SOMEWHAT GUSTY/BREEZY THROUGH MID/LATE EVENING TONIGHT BUT
EVENTUALLY...COOLING TEMPS SHOULD ALLOW THE SURFACE TO DECOUPLE
WITH WINDS DIMINISHING UNDER 10KTS BY WEDNESDAY MORNING. CMS
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* MEDIUM CONFIDENCE REGARDING WIND SPEEDS/GUSTS. CMS
//OUTLOOK FOR ORD/MDW FOR 12Z WEDNESDAY-12Z MONDAY...UPDATED 00Z...
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...CHANCE OF SHRA/TSRA.
SATURDAY...CHANCE OF SHRA/TSRA.
SUNDAY...CHANCE OF SHRA/TSRA.
RODRIGUEZ
&&
.MARINE...
202 PM CDT
LOW PRESSURE ACROSS THE NORTHEASTERN CONUS...WILL REMAIN IN PLACE
THROUGH WEDNESDAY. MEANWHILE...HIGH PRESSURE ACROSS NORTHERN CANADA
WILL BUILD SOUTHEASTWARD ACROSS SOUTH CENTRAL CANADA AND THE UPPER
MIDWEST BY WEDNESDAY. THESE TWO PRESSURE SYSTEMS WILL CONTINUE TO
PRODUCE NORTHERLY WINDS OF 20 TO 30 KT ACROSS LAKE MICHIGAN THROUGH
MIDWEEK. THE SURFACE HIGH IS EXPECTED TO SHIFT ACROSS THE WESTERN
GREAT LAKES WEDNESDAY NIGHT INTO THURSDAY. THIS WILL RESULT IN A
PERIOD OF LIGHT AND VARIABLE WINDS. BY LATE WEEK THE WINDS WILL
BECOME SOUTHERLY AS ANOTHER AREA OF LOW PRESSURE ACROSS THE PLAINS
STATES BEGINS TO SHIFT EASTWARD. THESE WINDS APPEAR TO CONTINUE INTO
THIS COMING WEEKEND.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FREEZE WARNING...ILZ003-ILZ004-ILZ005-ILZ008-ILZ010-ILZ011-
ILZ012 UNTIL 9 AM TUESDAY.
IN...NONE.
LM...SMALL CRAFT ADVISORY...NEARSHORE WINTHROP HARBOR TO NORTHERLY
IS UNTIL 10 PM TUESDAY.
SMALL CRAFT ADVISORY...NEARSHORE NORTHERLY IS TO MICHIGAN CITY
IN UNTIL 10 PM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
628 PM EDT TUE APR 10 2012
.SYNOPSIS...
COLD NORTHWEST FLOW WILL SUPPORT SNOW SHOWERS AT TIMES TONIGHT AND WEDNESDAY.
MIDWEST HIGH PRESSURE WILL PROVIDE DRY, MILDER WEATHER THURSDAY
INTO SATURDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
RECENT SURFACE DATA SHOWS COLDER TEMPERATURES ARRIVING FASTER THAN
WHAT MODELS EXPECTED. THE PRECIPITATION TYPE IS ALREADY SNOW, WHERE
SURFACE TEMPERATURES ARE COLDER THAN 42, DUE TO STEEP LOW LEVEL
LAPSE RATES. HENCE HAVE LOWERED TEMPERATURES FASTER TONIGHT AND
ADDED MENTION OF EXCLUSIVELY SNOW SHOWERS ONCE TEMPERATURES GO
COLDER THAN 42.
PER RECENT HRRR AND NAM MODEL OUTPUT, WHICH HAVE FORECASTED THE
COLDEST TEMPERATURES, HAVE LOWS FOR MOST PLACES COLDER THAN 32. SO
HAVE ENLARGED THE FREEZE WARNING TO COVER ALL AREAS.
WITH 850 MB TEMPERATURES PROJECTED AT BEST NR -5 C DURING THE NEXT
24 HOURS...SNOW SHOWERS WILL REMAIN THROUGH WEDNESDAY FOR MUCH OF
THE AREA...ALTHOUGH A CHANGE TO RAIN CAN BE EXPECTED FOR AREAS
WHERE SURFACE TEMPS RISE TOWARD THE MID 40S WEDNESDAY AFTERNOON.
WITH THE WARM GROUND AND LIMITED FREEZE DURATION OF SURFACE
TEMPS...EXPECT NO MORE THAN MINIMAL SNOW ACCUMULATION.
NAM MODEL PROFILES SUGGEST WINDS GUSTS CAN PEAK AROUND 30 MPH.
IN ADDITION...AS WIND VEERS MORE TOWARD THE NORTH ON WEDNESDAY...THE
FETCH OFF LAKE ERIE WILL DIMINISH...WHICH WL DECREASE THE SHOWER
COVERAGE VIA DRY ADVECTION. WITH ONGOING COLD ADVECTION...HIGH
TEMPERATURES WERE FORECAST ABOUT 15 DEGREES COLDER THAN NORMAL USING
LATEST NAM AND SREF GUIDANCE.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
WITH HIGH PRESSURE BUILDING OUT OF THE CENTRAL PLAINS...THE PRESSURE
GRADIENT OVER THE UPPER OHIO WILL DECREASE AND WIND WILL LIGHTEN
ON WED NIGHT. RESIDUAL LOW LEVEL MOISTURE WILL ALSO PUSH OFF TO
THE EAST...AND CLOUDS SHOULD GRADUALLY DIMINISH OVERNIGHT. WITH HIGH
PRESSURE IN THE VICINITY THURSDAY INTO FRIDAY...EXPECT DRY WEATHER.
SUB-FREEZING CONDITIONS ARE POSSIBLE IN ALL AREAS WEDNESDAY
NIGHT...AND PERHAPS AGAIN THURSDAY NIGHT. FOR NOW, WILL GO WITH A FREEZE
WATCH FOR WEDNESDAY NIGHT.
DAYTIME TEMPERATURES WILL SLOWLY MODERATE THURSDAY...AND RETURN
TO NORMAL LEVELS FRIDAY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MODELS IN GOOD AGREEMENT WITH RIDGE MOVING TO EAST COAST BY SATURDAY
MORNING. WARM AIR OVERSPREADS REGION ON SATURDAY WITH POSSIBLE
SHOWERS BY LATE DAY...PARTICULARLY ACROSS NORTHERN COUNTIES.
EXPECT CWA TO BE IN WARM SECTOR SUNDAY...BUT KEPT MAX TEMPS ABOUT
5 DEGREES COOLER THAN HPC GUIDANCE. MODELS BEGIN TO DIVERGE BY
MONDAY AS FRONT MOVES SLOWLY SOUTH ACROSS REGION WITH CHANCE OF
RAIN FROM LATE SUNDAY THROUGH TUESDAY. WITH CLOUDS AND RAIN ON
MONDAY AGAIN KEPT TEMPERATURES ABOUT 5 DEGREES COOLER THAN
GUIDANCE.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
COLDER AIR AND STEEPENING LAPSE RATES WL CONT TO DEVELOP SOUTHWARD
ACRS THE UPR OHIO REGION THIS EVE...ACCOMPANIED BY MVFR...OR NR
MVFR CIGS ALONG WITH SCT SNOW SHOWERS. BRIEF VISIBILITY REDUCTION
TO IFR WL RMN A POSSIBILITY...MAINLY AT FKL AND DUJ THROUGH THE
EVE.
DRY ADVECTION IS EXPECTED TO SUPPORT DIMINISHED SHOWER COVERAGE
AND IMPROVED CIGS ON WEDNESDAY AFTN DESPITE CONTINUED COLD ADVECTION.
WIND GUSTS ARE FORECAST TO DIMINISH TONIGHT AS MIXING
DIMINISHES...I.E. DECOUPLING OCCURS. WIND GUSTS WL RESUME AS
TEMPERATURES REACH CONVECTIVE THRESHOLDS ON WED AFTN.
OUTLOOK...SATURDAY THROUGH TUESDAY...
BUILDING HIGH PRES WL CONT GENL VFR INTO SATURDAY. WARM, MOIST ADVCTN
IS THEN FORECAST TO INCRS MID LEVEL CLOUDS ACROSS THE REGION BY
LATE SATURDAY. SHRA ARE POSSIBLE WITH THIS WARM SURGE...BUT THE
AREA IS PROGGED TO BE IN THE WARM SECTOR SUNDAY WITH GENERAL VFR
CONDITIONS. AN APPRCHING COLD FRONT IS THE EXPECTED TO UP THE
RESTRICTION POTENTIAL FOR THE START OF THE NEW WEEK.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FREEZE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
MORNING FOR MDZ001.
FREEZE WARNING FROM 2 AM TO 9 AM EDT WEDNESDAY FOR MDZ001.
OH...FREEZE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
MORNING FOR OHZ039>041-048>050-057>059-068-069.
FREEZE WARNING FROM 2 AM TO 9 AM EDT WEDNESDAY FOR OHZ039>041-
048>050-057>059-068-069.
PA...FREEZE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
MORNING FOR PAZ007>009-013>016-020>023-029-031-073>076.
FREEZE WARNING FROM 2 AM TO 9 AM EDT WEDNESDAY FOR PAZ007>009-
013>016-020>023-029-031-073>076.
WV...FREEZE WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
MORNING FOR WVZ001>004-012-021>023-041.
FREEZE WARNING FROM 2 AM TO 9 AM EDT WEDNESDAY FOR WVZ001>004-
012-021>023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
1010 PM MDT MON APR 9 2012
.UPDATE...
SKIES ARE CLEARING ACROSS MUCH OF CENTRAL AND WESTERN NEW MEXICO
AS THE UPPER RIDGE BUILDS INTO THE STATE ONCE AGAIN. A FEW LIGHT
SHOWERS AND SPRINKLES CONTINUE OVER SOUTH CENTRAL AND SOUTHEAST
AREAS SO CONTINUED SOME LOW END POPS FROM NEAR SOCORRO TO RUIDOSO
AND ROSWELL. A SIGNIFICANT BANK OF LOW CLOUDS IS DEVELOPING WEST
INTO THE NE PLAINS AS INDICATED BY THE GOES LOW CLOUD BASE PRODUCT.
ADDED SOME FOG AS WELL TO THE FAR SE PLAINS WHERE WETTING RAINS
OCCURRED TONIGHT AND THE LATEST RUC INDICATES A NEAR SATURATED
BOUNDARY LAYER WITH WEAK LOW LEVEL CONVERGENCE.
GUYER
&&
.PREV DISCUSSION...307 PM MDT MON APR 9 2012...
WIDELY SEPARATED SHOWERS AND THUNDERSTORMS HAVE POPPED UP ON QUE
ACROSS A GOOD PORTION OF THE FORECAST AREA THIS AFTERNOON. THE
WESTERN AND CENTRAL VARIETY ARE IN LARGE PART THE DRIER VARIETY
WITH JUST A VERY SMALL FOOTPRINT OF UP TO NEAR A TENTH OF AN INCH
IN SOME OF THE CELLS. BASED ON CURRENT HUMIDITY READINGS...A
MIXTURE OF WET AND DRY EXISTS ACROSS THE EAST WITH AMA RADAR
SHOWING SOME ENHANCED ECHOES ACROSS THE NORTHEAST PLAINS.
UNFORTUNATELY FDX RADAR WILL BE DOWN FOR THE REST OF TODAY. LATEST
SWOMCD FROM SPC SUGGESTS A POSSIBILITY OF SEVERE THROUGH THE
REMAINDER OF THE DAY ACROSS THE FAR EAST...ESPECIALLY SOUTHEAST
WHERE BETTER MOISTURE EXISTS. MICROBURST WIND AND PERHAPS EVEN
LARGE HAIL WOULD BE THE MAIN HAZARD WITH THIS ACTIVITY.
MODELS HAVE BEEN PRETTY CONSISTENT WITH DRAGGING THE CURRENT MID
LEVEL DRY SLOT OVER CALIFORNIA AND ARIZONA EASTWARD OVER THE STATE
DURING THE NEXT COUPLE OF DAYS. THIS MEANS LESSENING THUNDERSTORM
CHANCES FROM WEST TO EAST AND INCREASING DRYNESS IN THE
STORMS...ESPECIALLY ALONG THE MID LEVEL MOISTURE GRADIENT. THE
ONLY EXCEPTION TO THIS WOULD BE FOUND ACROSS THE EASTERN PLAINS
WHERE A STRENGTHENING OR SHARPENING DRYLINE IS EXPECTED.
THUS...SEVERE POTENTIAL WOULD INCREASE ACROSS THAT AREA THROUGH
WEDNESDAY. THE CULMINATION DAY STILL APPEARS TO BE WEDNESDAY
AFTERNOON AND OVERNIGHT ACROSS THE FAR EAST. WENT AHEAD AND PLACED
POSSIBILITY OF SEVERE STORMS IN THE FORECAST WORDING DUE TO A
BETTER THAN MODERATE CONFIDENCE OF A SIGNIFICANT SEVERE WX
OUTBREAK EVENT THERE.
THEREAFTER...NEW MEXICO EXPERIENCES MORE FIRE WX CONCERNS AS THE
DRYSLOT OVERTAKES THE AREA AND WINDS INCREASE IN EARNEST THURSDAY
AND FRIDAY AS THE UPPER TROUGH SLIDES OVER THE NORTHERN AND
CENTRAL ROCKIES. RESIDUAL STRONGER WIND FLOWS AND LOWER HUMIDITY
IS EXPECTED FOR FRIDAY AS WELL.
MODELS HAVE BECOME A BIT MORE CONSISTENT WITH THEIR DEPICTION OF
THE WEEKEND PERIOD ALTHOUGH HAVE BEEN SHAKY THE PAST 2 TO 3 DAYS
SO DIDNT ADJUST THE GRIDS FOR THAT TIME FRAME. BOTH GFS AND ECMWF
DIG A FAIRLY DEEP AND LARGE UPPER LOW INTO THE GREAT BASIN ON
FRIDAY AND FURTHER IT INTO PORTIONS OF THE ROCKIES AND SOUTHWEST
AREA DURING THE WEEKEND. THE WEEKEND APPEARS TO BE UNSETTLED BUT
THE JURY IS STILL OUT ON HOW MUCH PRECIPITATION THE STATE WOULD
GET...IF ANY. RIGHT NOW...THE MODELS ARE BULLISH FOR THE SUNDAY
PERIOD ESPECIALLY AS A BACK DOOR FRONT PUSHES IN FROM THE NORTH.
SUSPECT THAT THE MODELS WILL VARY QUITE A BIT DURING THE NEXT FEW
DAYS WITH THIS SYSTEM SO STAY TUNED.
50
.AVIATION...
VFR CONDITIONS ARE FORECAST TO PERSIST THROUGH THE NEXT 24 HOURS
AT TAF SITES...BUT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
WILL BE ACCOMPANIED BY SHORT-LIVED MVFR CONDITIONS AND WIND GUSTS
NEAR 40 MPH. A WSW LOW LEVEL FLOW WILL BECOME MORE SSW
OVERNIGHT...WITH TYPICAL DRAINAGE-TYPE WINDS EARLY TUESDAY
MORNING. NEXT AVIATION DISCUSSION SCHEDULED FOR 09Z. 11
.FIRE WEATHER...
...EXTENDED PERIOD OF CRITICAL FIRE WEATHER CONDITIONS WEDNESDAY
THROUGH SATURDAY...
ABUNDANT ATMOSPHERIC MOISTURE AND DAYTIME HEATING RESULTED IN
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS MONDAY
AFTERNOON...WHICH WILL CONTINUE INTO THE EVENING HOURS BEFORE
FOLLOWING A TYPICAL DIURNAL DOWNTREND. WETTING RAINS FROM THIS ROUND
OF CONVECTION WILL BE SPOTTY AT BEST.
THE FOCUS FOR CONVECTION WILL SHIFT EAST A BIT EACH DAY THROUGH
WEDNESDAY AS THE PACIFIC DRY SLOT BEGINS TO WORK-OVER THE STATE AND
RELATIVE HUMIDITIES TREND DOWN...EXCEPT OVER THE EASTERN PLAINS
WHERE GULF MOISTURE WILL REMAIN. NEAR-CRITICAL FIRE WEATHER
CONDITIONS ARE POSSIBLE FOR AN HOUR OR TWO LATE TUESDAY AFTERNOON
ACROSS THE WEST CENTRAL MOUNTAINS AND HIGHLANDS.
BY WEDNESDAY AFTERNOON...DRY SOUTHWESTERLIES WILL PREVAIL ALONG AND
WEST OF THE CENTRAL MOUNTAIN CHAIN AND WINDS WILL LIKELY HIT
CRITICAL THRESHOLDS ACROSS PORTIONS OF ZONES 101...105 AND 109. THE
FIRE WEATHER WATCH COVERING THOSE ZONES LOOKS GOOD AND THE LATEST
FORECAST DATA DOES NOT SUPPORT EXPANDING IT FURTHER EAST AT THIS
TIME. WETTING RAINS ARE POSSIBLE WEDNESDAY INTO THE EARLY MORNING
HOURS THURSDAY ACROSS THE EASTERN PLAINS AS THE DRY LINE ADVANCES
EASTWARD AND SPARKS A ROUND OF POTENTIALLY SEVERE CONVECTION.
DRY WESTERLIES WILL OVERTAKE THE ENTIRE AREA THURSDAY AND
VENTILATION WILL CONTINUE AN UPWARD TREND. CRITICAL FIRE WEATHER
CONDITIONS ARE POSSIBLE EAST OF THE CENTRAL MOUNTAIN CHAIN THURSDAY
AFTERNOON AND EVENING. BY FRIDAY...STRONGER WINDS ALOFT WILL MOVE
OVER THE STATE IN ADVANCE OF A POTENT UPPER LEVEL TROUGH. AFTER A
LITTLE DAYTIME MIXING...WINDY CONDITIONS ARE FORECAST WITH
WIDESPREAD CRITICAL FIRE WEATHER CONDITIONS. A LITTLE RELIEF IS
FORECAST SATURDAY AS COOLER AIR ASSOCIATED WITH THE EAST-BOUND
TROUGH BEGINS TO MOVE INTO WESTERN ZONES. CRITICAL FIRE WEATHER
CONDITIONS ARE STILL POSSIBLE SATURDAY...BUT CONFINED TO THE EASTERN
PLAINS.
11
&&
.PRELIMINARY POINT TEMPS/POPS UPDATE...
FARMINGTON...................... 43 79 45 77 / 0 0 0 0
DULCE........................... 30 75 31 75 / 0 0 5 5
CUBA............................ 39 77 39 78 / 10 5 5 5
GALLUP.......................... 35 75 37 73 / 0 0 0 0
EL MORRO........................ 33 72 33 71 / 10 0 0 0
GRANTS.......................... 35 77 36 75 / 10 5 0 0
QUEMADO......................... 41 75 41 73 / 5 0 0 0
GLENWOOD........................ 47 81 42 78 / 5 5 0 0
CHAMA........................... 34 69 37 70 / 5 10 5 10
LOS ALAMOS...................... 50 74 51 76 / 10 5 5 5
PECOS........................... 46 73 46 75 / 20 10 10 10
CERRO/QUESTA.................... 38 74 37 75 / 10 10 10 10
RED RIVER....................... 37 62 36 64 / 10 20 10 10
ANGEL FIRE...................... 33 64 32 66 / 20 20 10 10
TAOS............................ 35 74 36 76 / 10 10 5 10
MORA............................ 38 70 40 73 / 20 20 10 10
ESPANOLA........................ 39 81 37 82 / 10 10 5 5
SANTA FE........................ 48 74 47 76 / 10 10 5 5
SANTA FE AIRPORT................ 45 78 45 80 / 10 10 5 5
ALBUQUERQUE FOOTHILLS........... 57 79 52 80 / 10 5 5 5
ALBUQUERQUE HEIGHTS............. 53 80 53 81 / 10 5 5 5
ALBUQUERQUE VALLEY.............. 51 81 49 83 / 10 5 5 0
ALBUQUERQUE WEST MESA........... 50 81 47 82 / 10 0 5 0
LOS LUNAS....................... 48 82 45 83 / 10 5 5 0
RIO RANCHO...................... 50 81 47 81 / 10 0 5 0
SOCORRO......................... 49 84 47 85 / 10 5 5 0
SANDIA PARK/CEDAR CREST......... 44 77 43 79 / 10 10 5 10
TIJERAS......................... 47 79 46 81 / 10 10 5 5
MORIARTY/ESTANCIA............... 45 76 44 78 / 20 10 10 5
CLINES CORNERS.................. 46 74 45 76 / 30 20 10 10
GRAN QUIVIRA.................... 47 77 48 79 / 20 10 10 5
CARRIZOZO....................... 43 81 43 82 / 20 10 10 10
RUIDOSO......................... 44 73 47 74 / 30 20 20 10
CAPULIN......................... 46 68 47 71 / 20 30 30 20
RATON........................... 39 75 42 78 / 20 30 20 20
SPRINGER........................ 38 74 40 77 / 30 30 20 20
LAS VEGAS....................... 43 74 43 76 / 30 20 10 10
CLAYTON......................... 49 71 54 72 / 20 30 40 40
ROY............................. 45 73 49 74 / 20 30 20 20
CONCHAS......................... 51 80 52 81 / 20 30 20 20
SANTA ROSA...................... 50 81 52 84 / 30 20 20 20
TUCUMCARI....................... 56 83 59 81 / 30 30 30 30
CLOVIS.......................... 53 79 58 79 / 40 30 40 30
PORTALES........................ 55 81 59 81 / 40 30 40 30
FORT SUMNER..................... 52 86 55 88 / 30 20 30 20
ROSWELL......................... 50 86 57 88 / 20 20 20 20
PICACHO......................... 47 82 50 86 / 30 20 20 20
ELK............................. 45 79 49 81 / 30 20 20 10
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH WEDNESDAY
EVENING FOR THE FOLLOWING ZONES...NMZ101-105-109.
&&
$$
GUYER
AREA FORECAST DISCUSSION
NWS TULSA OK
927 PM CDT WED APR 11 2012
.DISCUSSION...
EASTERN OK AND NORTHWEST AR REMAIN ON THE COOL AND STABLE SIDE OF
A STATIONARY FRONT DRAPED FROM NE TX TO THE NORTHERN TX PANHANDLE.
CLUSTERS OF STORMS CURRENTLY IN THE PANHANDLE REGION ARE FORECAST
TO SLOWLY WORK THEIR WAY EAST INTO WEST/NORTHWEST OK TONIGHT AS
WARM ADVECTION INCREASES DUE TO STRENGTHENING LLJ OVER THE HIGH
PLAINS. CHANCES ARE QUITE LOW THAT THIS ACTIVITY WILL MAKE IT ALL
THE WAY OVER INTO NORTHEAST OK BY 12Z. THE NEW 00Z NAM AND THE
LATEST RUNS OF THE HRRR SUGGEST IT WILL STAY WEST. THE SREF AND
OTHER ENSEMBLE GUIDANCE KEEP LOW POPS IN THE FAR WEST. THUS...I
WILL TREND THE FORECAST THAT WAY...KEEPING ONLY A LOW SLGT CHC POP
MAINLY WEST OF HWY 75. ALSO MADE A SLIGHT DOWNWARD TWEAK TO THE
LOWS AS PARTLY CLOUDY TO MOSTLY CLEAR SKIES HAS ALLOWED TEMPS TO
DROP OFF THIS EVENING. CLOUDS SHOULD INCREASE SOME AFTER MIDNIGHT
HOWEVER...AND THIS WILL PREVENT A SIGNIFICANT DROP IN TEMPS
TONIGHT. UPDATED PRODUCTS HAVE BEEN SENT.
LACY
&&
.PREV DISCUSSION... /ISSUED 640 PM CDT WED APR 11 2012/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
SCATTERED TO BROKEN CLOUD DECKS BETWEEN 4-10KFT WILL CONTINUE TO
BE COMMON ACROSS REGION THIS EVENING AND TONIGHT WITH EASTERLY
WINDS. A WARM FRONT IS EXPECTED TO PUSH BACK NORTHWARD DURING THE
DAY THURSDAY WITH WINDS BECOMING SOUTHEASTERLY AND BREEZY. A
CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE WITH HIGHER
CHANCES ACROSS NORTHEAST OKLAHOMA. THUS...WILL ADD PROB30 GROUPS
FOR BVO/TUL/RVS.
PREV DISCUSSION... /ISSUED 403 PM CDT WED APR 11 2012/
DISCUSSION...
THE FRONTAL BOUNDARY THAT PUSHED SOUTH OF THE AREA TUESDAY WILL BE
RETURNING NORTH AS A WARM FRONT LATE TONIGHT AND THURSDAY. A FEW
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE BEGINNING LATE TONIGHT
AND ESPECIALLY DURING THE DAY THURSDAY...MAINLY ACROSS NORTHEAST
OKLAHOMA...BUT RAINFALL IS LIKELY TO REMAIN FAIRLY LIGHT FOR THE
MOST PART. TEMPERATURES WILL STRUGGLE AGAIN FOR MUCH OF THURSDAY
BUT WILL BEGIN TO RALLY LATE IN THE DAY AS THE WARM FRONT SURGES
NORTH.
A WARM AND HUMID AIRMASS WILL BE IN PLACE FRIDAY THROUGH THE
WEEKEND. SEVERE THUNDERSTORMS WILL DEVELOP EACH DAY TO OUR WEST
ALONG AND AHEAD OF A DRYLINE AND THESE STORMS WILL HAVE A CHANCE
TO MAKE IT INTO AT LEAST THE WESTERN AND NORTHERN PARTS OF OUR
AREA BOTH FRIDAY AND SATURDAY EVENING WITH ALL FACETS OF SEVERE
WEATHER POSSIBLE. MORE SCATTERED...AND LIKELY AT LEAST A BIT LESS
INTENSE...CONVECTION MAY ALSO OCCUR FARTHER SOUTH AND EAST DURING
THIS TIME FRAME.
THE GREATEST COVERAGE OF SHOWERS AND STORMS IN OUR AREA WILL BE
SUNDAY AND SUNDAY NIGHT AS A COLD FRONT MOVES INTO AND ACROSS THE
AREA. THE ECMWF HAS JOINED THE UKMET AND GEM AT BEING MORE
PROGRESSIVE WITH THIS SYSTEM WITH ONLY THE GFS LAGGING BEHIND.
SINCE THE MODELS HAVE SHOWN POOR RUN TO RUN CONSISTENCY ON
THIS...WILL KEEP SOME POPS GOING INTO MONDAY NIGHT BUT WILL LOWER
TEMPERATURES DURING THIS TIME FRAME TO AT LEAST AN ECMWF/GFS MOS
COMPROMISE SOLUTION.
COOL AND DRY WEATHER LOOKS TO FOLLOW THIS SYSTEM FOR THE MIDDLE OF
NEXT WEEK WITH SOME FROST POSSIBLE IN LOW LYING AREAS BY NEXT
WEDNESDAY MORNING.
WENT A BIT WARMER THAN GUIDANCE FOR LOW TEMPERATURES TONIGHT BUT
OTHERWISE STAYED CLOSE TO GUIDANCE TEMPERATURES THE NEXT COUPLE
DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 53 69 61 76 / 10 40 20 20
FSM 49 67 53 78 / 10 20 10 10
MLC 53 70 62 77 / 10 30 10 20
BVO 49 68 59 76 / 10 50 30 30
FYV 43 64 53 75 / 10 20 20 10
BYV 42 64 51 75 / 10 20 20 10
MKO 51 69 57 76 / 10 30 20 20
MIO 46 65 55 75 / 10 30 30 20
F10 53 70 61 76 / 10 30 20 20
HHW 54 71 59 77 / 10 20 10 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
LONG TERM....30
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
849 PM MDT WED APR 11 2012
.UPDATE...02Z SURFACE ANALYSIS HAD LOW OVER WESTERN WY WITH HIGH
OVER MN/IA AND DECENT GRADIENT OVER THE CWA. DIURNAL EFFECTS
ALLOWING BOUNDARY LAYER TO DECOUPLE SOME THIS EVENING AND THUS WINDS
HAVE SLACKENED ENOUGH OVER NORTHWEST SD TO ALLOW THE WIND ADVISORY
TO EXPIRE.
00Z KUNR SOUNDING SHOWED LARGE INVERSION WITH VERY SHALLOW
MOISTURE LAYER AROUND 750MB...WHICH IS ALSO THE BASE OF ABOUT
961J/KG MUCAPE. LOW LEVEL JET HAS BEEN UNABLE TO TAP INTO
MUCAPE...LIKELY BECAUSE THE LAYER IS SO THIN. MOISTURE IS
RESPONSIBLE FOR ST EAST/SOUTH OF THE BLACK HILLS PER FOG PRODUCT.
LOOKING UPSTREAM...SPEED MAX/SHORTWAVE OVER EASTERN UT MAKING IT/S
WAY NORTH. 18Z/21Z/00Z RUC HAVE PAINTED SLOWER START TO POPS IN
THE CWA TONIGHT...AND 00Z NAM FOLLOWS THIS TREND AS WELL AS
IR/REGIONAL RADAR LOOPS. WILL PULL BACK NORTHEAST EXTENT OF POPS
TONIGHT. BUT AS SHORTWAVE REACHES WY CWA FROM 06Z-09Z...SHOULD
SEE ELEVATED -SHRA/ISOLATED -TSRA DEVELOP AND QUICKLY MOVE
NORTHEAST ACROSS THE CWA THROUGH THURSDAY MORNING.
UPDATED FORECAST WILL REFLECT THESE THOUGHTS.
&&
.AVIATION...00Z TAFS UPDATE
BREEZY/WINDY CONDITIONS WILL CONTINUE TONIGHT. AREA OF ST OVER THE
SD PLAINS/SOUTHEAST WY WILL EXPAND TONIGHT BRINGING AREAS OF MVFR
CIGS. -SHRA ARE POSSIBLE OVERNIGHT WITH ISOLATED -TSRA. CONDITIONS
WILL IMPROVE FROM SOUTHWEST TO NORTHEAST THURSDAY AS WINDS GAIN A
WESTERLY COMPONENT.
&&
.PREV DISCUSSION... /ISSUED 300 PM MDT WED APR 11 2012/
DISCUSSION...CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER
EAST-CENTRAL ID...WITH SECONDARY AREA OF LOW PRESSURE OVER
SOUTHWESTERN WY. HIGH PRESSURE REMAINS IN PLACE EAST OF THE
AREA...OVER THE FAR EASTERN DAKOTAS AND MN. UPPER LEVEL ANALYSIS
SHOWS STRONG RIDGE IN PLACE OVER THE HIGH PLAINS...WITH LONGWAVE
TROF ALONG THE WEST COAST. STRONGER SHORTWAVE IS IN PLACE OVER
SOUTHERN NV...MOVING NORTHEAST ALONG BACK SIDE OF THE RIDGE.
ANOTHER WEAKER SHORTWAVE IS NOTED OVER CO...MOVING NORTH-
NORTHEASTWARD. GUSTY SOUTH TO SOUTHEAST WINDS ARE IN PLACE OVER
MUCH OF THE AREA...WITH THE STRONGEST WINDS OVER NORTHWESTERN SD.
SKIES ARE MOSTLY SUNNY ACROSS MUCH OF THE AREA...EXCEPT PARTLY
SUNNY/MOSTLY CLOUDY ACROSS SOUTHWESTERN SD. TEMPS RANGE FROM THE
MID TO UPPER 50S OVER THE BLACK HILLS TO NEAR 70 OVER CAMPBELL
COUNTY WY.
AN UNSETTLED WEATHER PATTERN WILL DEVELOP OVER THE AREA TONIGHT
AND PERSIST THROUGH THE WEEKEND AS TROF ALONG THE WEST COAST MOVES
EAST AND ALLOWS A SERIES OF WEATHER SYSTEMS TO CROSS THE REGION.
THE BETTER CHANCES FOR PCPN IN THE NEAR TERM WILL BE LATER TONIGHT
INTO EARLY THURSDAY...AND AGAIN LATER THURSDAY NIGHT INTO FRIDAY.
AFTER A WARM DAY IN MOST AREAS ON THURSDAY...A GRADUAL COOLING
TREND CAN BE EXPECTED INTO THE WEEKEND AS WELL.
FOR TONIGHT...WINDS WILL REMAIN GUSTY INTO THE EVENING IN MOST
AREAS...WITH THE GUSTY WINDS LINGERING THROUGH MUCH OF THE NIGHT
ACROSS NORTHWESTERN SD. HAVE DECIDED TO CANCEL THE WIND ADVISORY
FOR THE SOUTHWESTERN SD PLAINS AS WINDS HAVE STAYED BELOW ADVISORY
CRITERIA AND GENERALLY WILL INTO THIS EVENING. CHANCES FOR SHOWERS
AND A FEW THUNDERSTORMS WILL INCREASE FROM THE SOUTHWEST THIS
EVENING AS SHORTWAVE OVER CO MOVES ACROSS THE AREA. BEST CHANCES
WILL BE ACROSS THE BLACK HILLS AREA AND EASTWARD DURING THE
OVERNIGHT INTO THURSDAY MORNING. TEMPS WILL REMAIN RELATIVELY
MILD...WITH LOWS IN THE UPPER 30S AND 40S.
THE MAIN SHORTWAVE IS PROGGED TO EXIT THE AREA IN THE MORNING...
WITH SOUTHWESTERLY FLOW ALOFT REMAINING IN PLACE. WEAKER IMBEDDED
ENERGY IN THE FLOW COULD BRING ISOLATED SHOWERS AND STORMS IN THE
AFTERNOON...BUT MOST AREAS WILL LIKELY REMAIN DRY. SOUTHWESTERLY
WINDS ACROSS MUCH OF THE AREA WILL BRING WARMER AIR IN AHEAD OF
APPROACHING FRONT...WITH HIGHS IN THE 60S AND LOWER 70S...WARMEST
SOUTH AND EAST OF THE BLACK HILLS.
MODELS BEGIN TO DIVERGE FOR THURSDAY NIGHT AND BEYOND AS LOW
PRESSURE AND COLD FRONT CROSS THE AREA. THERE IS RELATIVELY LOW
CONFIDENCE IN THE FORECAST THROUGH THE WEEKEND. RIGHT NOW...THE
MAIN CHANCES FOR SHOWERS THURSDAY NIGHT LOOK TO BE ACROSS
NORTHEASTERN WY...THE BLACK HILLS AND TOWARD CENTRAL SD. A FEW
THUNDERSTORMS ARE POSSIBLE...ESPECIALLY TOWARD SOUTH CENTRAL SD.
TEMPS SHOULD BE COLD ENOUGH OVERNIGHT AND EARLY FRIDAY FOR SNOW
SHOWERS OVER THE HIGHER BLACK HILLS. LOWS WILL BE IN THE MID 30S
TO MID 40S AT MOST LOCATIONS.
SOUTHWESTERLY FLOW ALOFT REMAINS OVER THE AREA ON FRIDAY...WITH
ADDITIONAL UPPER LEVEL DISTURBANCES IN THE FLOW LIKELY ALLOWING
SOME SHOWERS AND ISOLATED STORMS TO DEVELOP...ESPECIALLY DURING
THE AFTERNOON AND EVENING HOURS. CONSENSUS OF THE MODELS HAS THE
MAJORITY OF ACTIVITY DEVELOPING OVER THE BLACK HILLS AREA...SO
WILL KEEP HIGHEST POPS IN THAT AREA. HIGHS LOOK TO BE IN THE UPPER
50S TO MID 60S AT MOST LOCATIONS...50S ACROSS THE BLACK HILLS.
EXTENDED...LARGE UPPER TROUGH WILL KEEP COOL AND UNSETTLED WEATHER
OVER THE NORTHERN PLAINS FROM SATURDAY THROUGH TUESDAY. A SERIES OF
UPPER WAVES WILL ROTATE OUT OF THE TROUGH AND CROSS THE NORTHERN
PLAINS DURING THIS PERIOD. MODEL SOLUTIONS CONTINUE TO DIFFER IN THE
DETAILS. FOR NOW WILL CONTINUE WITH A BLEND OF THE LATEST SOLUTIONS
AND BROAD BRUSH PRECIP CHANCES. TEMPERATURES MAY BE COLD ENOUGH AT
THE HIGHER ELEVATIONS FOR SOME LIGHT SNOW ACCUMULATIONS BOTH
SATURDAY NIGHT AND SUNDAY NIGHT. TEMPERATURES WILL BE NEAR OR
SLIGHTLY COOLER THAN NORMAL THROUGH TUESDAY.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
SHORT TERM...HELGESON
LONG TERM....WFO UNR
AVIATION...HELGESON
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
922 PM CDT WED APR 11 2012
.UPDATE...
OLD FRONTAL BOUNDARY COMBINED WITH WEAK OUTFLOW FROM LATE DAY
STORMS NORTH AND EAST OF THE DFW METRO EARLIER HAS NOW SLID WEST
AS A FAIRFIELD...CORISCANA...FORT WORTH...AND BRIDGEPORT LINE...
WITH A DRIER AND SLIGHTLY COOLER AIRMASS BEHIND IT WITH EAST
WINDS 10 TO 15 MPH. HAVE LOWERED OVERNIGHT LOWS 2-4 DEGREES
BEHIND THE BOUNDARY WITH LESS COULD COVER AND WINDS EXPECTED TO
SUBSIDE. AREAS FURTHER SOUTH AND WEST WILL CONTINUE SOUTHEAST
AROUND 10 MPH OVERNIGHT WITH SLIGHTLY HIGHER SURFACE DEW PTS.
MODELS OUTSIDE OF THE NAM12/HRRR ARE WAY OVERDOING EXPECTED
CONVECTION DUE TO BEING TOO UNSTABLE AND TOO FAST WITH FORWARD
PROPAGATION OF STORMS OCCURRING ACROSS TX PANHANDLE AND WESTERN
SOUTH PLAINS. 00Z FWD SOUNDING ALSO INDICATING BARELY AN INCH OF
PWAT WITH ONLY 400 J/KG CAPE...WITH BEST LAPSE RATES NEAR 7 DEG
C/KM REMAINING ACROSS WESTERN RED RIVER VALLEY AND FAR WESTERN
COUNTIES OVERNIGHT.
WILL CARRY A CHANCE FOR SHOWERS AND NON-SEVERE STORMS BETWEEN 09Z-
15Z THURSDAY MORNING NW OF A SHERMAN...DECATUR...MINERAL WELLS LINE
WITH A ISOLATED COVERAGE AS FAR SOUTHEAST AS A DFW METRO TO
GOLDTHWAITE LINE LATE TONIGHT. AGAIN...WEAK WIND THROUGH 500MB
...SEMI-MOIST ADIABATIC THERMODYNAMIC PROFILES...AND A WEAK LLJ
INDICATE STORMS WILL WEAKEN CONSIDERABLY BEFORE AFFECTING AREAS
WEST THROUGH NORTH OF DFW AROUND DAYBREAK. HAVE ADJUSTED POPS
ACCORDINGLY THROUGH MIDDAY THURSDAY.
05/
&&
.AVIATION...
AVIATION CONCERNS REVOLVE AROUND THE LONGEVITY AND PATH OF THIS
AFTERNOON/EVENING CONVECTION IN THE PANHANDLE. CURRENT MODEL RUNS
WEAKEN THE CONVECTION BEFORE REACHING AIRPORTS...SO DID NOT ADD
ANY CONVECTION TO THESE TAFS. WILL MONITOR THIS EVENING/S
GUIDANCE TRENDS...INCLUDING HRRR AND TEXAS TECH WRF AND AMEND IF
CONVECTION APPEARS MORE LIKELY. SHOULD IT OCCUR...TIME FRAME FOR
TAF SITES WOULD PROBABLY BE SOMEWHERE IN THE 10Z-13Z TIME FRAME.
OTHERWISE...MORNING STRATUS WILL RETURN ONCE AGAIN. 84
&&
.PREV DISCUSSION... /ISSUED 315 PM CDT WED APR 11 2012/
SCATTERED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ALONG A WEAK
SURFACE FRONT JUST TO THE NORTHEAST OF THE DALLAS-FORT WORTH AREA
THIS AFTERNOON. THE BOUNDARY EXTENDED ALONG A LINE FROM AROUND
BOWIE TO PLANO TO CANTON AT 3 PM AND CONTINUES TO SAG SLOWLY TO
THE SOUTHWEST TOWARDS THE METROPLEX. WITH MODEST INSTABILITY
PRESENT...A FEW STORMS WILL BE STRONG WITH BRIEF HEAVY RAIN AND
SMALL HAIL. STORM MOTION IS VERY SLOW GIVEN WEAK MID LEVEL
FLOW...WITH MOVEMENT GENERALLY TO THE SOUTHEAST LESS THAT 10 MPH.
ACTIVITY SHOULD LINGER INTO THE EARLY EVENING HOURS AND GRADUALLY
DIMINISH AS SURFACE HEATING WANES AND SUBSIDENCE FROM THE UPPER
RIDGE TAKES HOLD. WILL DECREASE THE CHANCE POPS TO SLIGHT CHANCE
AFTER 7 PM FOR AREAS CURRENTLY AFFECTED BY FRONTAL ACTIVITY.
NEXT...WILL BE WATCHING A SHORTWAVE VAGUELY SHOWING UP OVER NEW
MEXICO ON THE WATER VAPOR SATELLITE. MODELS DEPICT THIS FEATURE
ROTATING EAST AROUND THE 500 MB RIDGE AND ENHANCING ACTIVITY
CURRENTLY DEVELOPING OVER NORTHWEST TEXAS. FEEL THIS ACTIVITY HAS
THE POTENTIAL TO BECOME ORGANIZED AND APPROACH THE AREA FROM THE
NORTHWEST TONIGHT...ESPECIALLY GIVEN THE PRESENCE OF THE SURFACE
BOUNDARY AND ASSOCIATED AXIS OF MOISTURE AND INSTABILITY TO WORK
WITH. NAM MAY ONCE AGAIN BE TOO AGGRESSIVE WITH MCS/COLD POOL
DEVELOPMENT...AND SUBSEQUENT SOLUTION OF WIDESPREAD PRECIP NORTH
OF I 20 AFTER MIDNIGHT TONIGHT. NEVERTHELESS IT CANNOT BE
COMPLETELY IGNORED...AND WILL INCLUDE CHANCE POPS OVER THE
NORTHWESTERN COUNTIES FOR THE OVERNIGHT HOURS...WITH SLIGHT CHANCE
FURTHER SOUTHEAST INCLUDING THE DALLAS FORT WORTH METROPLEX.
THE UPPER RIDGE WILL CONTINUE TO SHIFT SLOWLY EAST OVER THE NEXT
COUPLE OF DAYS. FLOW WILL TRANSITION TO SOUTHWESTERLY AT THE MID
AND UPPER LEVELS AS A LONGWAVE TROUGH DEVELOPS OVER THE WESTERN
CONUS. LOW-END POPS WILL BE POSSIBLE AS WE APPROACH THE WEEKEND
DUE MAINLY TO WARM ADVECTION SHOWERS. THIS WILL CHANGE ABRUPTLY
INTO WIDESPREAD CONVECTION LATE IN THE WEEKEND AS THE UPPER TROUGH
OVERSPREADS THE REGION...ACCOMPANIED BY A PACIFIC COLD FRONT.
AS WITH ANY PROGRESSIVE SYNOPTIC SCALE TROUGH DURING THE SPRING
MONTHS...LOCALLY HEAVY RAIN AND SEVERE WEATHER COULD BOTH BE A
GOOD POSSIBILITY AS THE SYSTEM SWINGS THROUGH THE REGION. COOLER
DRIER AIR IS THEN EXPECTED BY TUESDAY OF NEXT WEEK AS THE UPPER
LEVEL SYSTEM HEADS FOR THE EAST COAST AND THE FRONT MOVES EAST OF
THE STATE.
30
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 61 78 64 79 64 / 10 10 10 10 10
WACO, TX 63 79 64 78 64 / 10 10 10 10 10
PARIS, TX 53 73 60 76 60 / 10 20 10 10 10
DENTON, TX 58 77 64 77 63 / 10 20 10 10 10
MCKINNEY, TX 56 75 63 75 62 / 10 20 10 10 10
DALLAS, TX 62 78 64 78 64 / 10 10 10 10 10
TERRELL, TX 58 76 62 78 61 / 10 10 10 10 10
CORSICANA, TX 61 78 62 79 61 / 10 10 10 10 10
TEMPLE, TX 63 79 63 79 65 / 10 10 10 10 10
MINERAL WELLS, TX 61 78 62 78 64 / 20 20 10 20 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
84/05
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
648 PM CDT WED APR 11 2012
.AVIATION...
AVIATION CONCERNS REVOLVE AROUND THE LONGEVITY AND PATH OF THIS
AFTERNOON/EVENING CONVECTION IN THE PANHANDLE. CURRENT MODEL RUNS
WEAKEN THE CONVECTION BEFORE REACHING AIRPORTS...SO DID NOT ADD
ANY CONVECTION TO THESE TAFS. WILL MONITOR THIS EVENING/S
GUIDANCE TRENDS...INCLUDING HRRR AND TEXAS TECH WRF AND AMEND IF
CONVECTION APPEARS MORE LIKELY. SHOULD IT OCCUR...TIME FRAME FOR
TAF SITES WOULD PROBABLY BE SOMEWHERE IN THE 10Z-13Z TIME FRAME.
OTHERWISE...MORNING STRATUS WILL RETURN ONCE AGAIN. 84
&&
.PREV DISCUSSION... /ISSUED 315 PM CDT WED APR 11 2012/
SCATTERED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ALONG A WEAK
SURFACE FRONT JUST TO THE NORTHEAST OF THE DALLAS-FORT WORTH AREA
THIS AFTERNOON. THE BOUNDARY EXTENDED ALONG A LINE FROM AROUND
BOWIE TO PLANO TO CANTON AT 3 PM AND CONTINUES TO SAG SLOWLY TO
THE SOUTHWEST TOWARDS THE METROPLEX. WITH MODEST INSTABILITY
PRESENT...A FEW STORMS WILL BE STRONG WITH BRIEF HEAVY RAIN AND
SMALL HAIL. STORM MOTION IS VERY SLOW GIVEN WEAK MID LEVEL
FLOW...WITH MOVEMENT GENERALLY TO THE SOUTHEAST LESS THAT 10 MPH.
ACTIVITY SHOULD LINGER INTO THE EARLY EVENING HOURS AND GRADUALLY
DIMINISH AS SURFACE HEATING WANES AND SUBSIDENCE FROM THE UPPER
RIDGE TAKES HOLD. WILL DECREASE THE CHANCE POPS TO SLIGHT CHANCE
AFTER 7 PM FOR AREAS CURRENTLY AFFECTED BY FRONTAL ACTIVITY.
NEXT...WILL BE WATCHING A SHORTWAVE VAGUELY SHOWING UP OVER NEW
MEXICO ON THE WATER VAPOR SATELLITE. MODELS DEPICT THIS FEATURE
ROTATING EAST AROUND THE 500 MB RIDGE AND ENHANCING ACTIVITY
CURRENTLY DEVELOPING OVER NORTHWEST TEXAS. FEEL THIS ACTIVITY HAS
THE POTENTIAL TO BECOME ORGANIZED AND APPROACH THE AREA FROM THE
NORTHWEST TONIGHT...ESPECIALLY GIVEN THE PRESENCE OF THE SURFACE
BOUNDARY AND ASSOCIATED AXIS OF MOISTURE AND INSTABILITY TO WORK
WITH. NAM MAY ONCE AGAIN BE TOO AGGRESSIVE WITH MCS/COLD POOL
DEVELOPMENT...AND SUBSEQUENT SOLUTION OF WIDESPREAD PRECIP NORTH
OF I 20 AFTER MIDNIGHT TONIGHT. NEVERTHELESS IT CANNOT BE
COMPLETELY IGNORED...AND WILL INCLUDE CHANCE POPS OVER THE
NORTHWESTERN COUNTIES FOR THE OVERNIGHT HOURS...WITH SLIGHT CHANCE
FURTHER SOUTHEAST INCLUDING THE DALLAS FORT WORTH METROPLEX.
THE UPPER RIDGE WILL CONTINUE TO SHIFT SLOWLY EAST OVER THE NEXT
COUPLE OF DAYS. FLOW WILL TRANSITION TO SOUTHWESTERLY AT THE MID
AND UPPER LEVELS AS A LONGWAVE TROUGH DEVELOPS OVER THE WESTERN
CONUS. LOW-END POPS WILL BE POSSIBLE AS WE APPROACH THE WEEKEND
DUE MAINLY TO WARM ADVECTION SHOWERS. THIS WILL CHANGE ABRUPTLY
INTO WIDESPREAD CONVECTION LATE IN THE WEEKEND AS THE UPPER TROUGH
OVERSPREADS THE REGION...ACCOMPANIED BY A PACIFIC COLD FRONT.
AS WITH ANY PROGRESSIVE SYNOPTIC SCALE TROUGH DURING THE SPRING
MONTHS...LOCALLY HEAVY RAIN AND SEVERE WEATHER COULD BOTH BE A
GOOD POSSIBILITY AS THE SYSTEM SWINGS THROUGH THE REGION. COOLER
DRIER AIR IS THEN EXPECTED BY TUESDAY OF NEXT WEEK AS THE UPPER
LEVEL SYSTEM HEADS FOR THE EAST COAST AND THE FRONT MOVES EAST OF
THE STATE.
30
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 63 78 64 79 64 / 20 10 10 10 10
WACO, TX 63 79 64 78 64 / 10 10 10 10 10
PARIS, TX 53 73 60 76 60 / 20 10 10 10 10
DENTON, TX 62 77 64 77 63 / 30 10 10 10 10
MCKINNEY, TX 59 75 63 75 62 / 20 10 10 10 10
DALLAS, TX 62 78 64 78 64 / 20 10 10 10 10
TERRELL, TX 60 76 62 78 61 / 20 10 10 10 10
CORSICANA, TX 61 78 62 79 61 / 20 10 10 10 10
TEMPLE, TX 63 79 63 79 65 / 10 10 10 10 10
MINERAL WELLS, TX 61 78 62 78 64 / 30 10 10 20 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS AMARILLO TX
345 PM CDT TUE APR 10 2012
.DISCUSSION...
AFTERNOON VIS SATELLITE IMAGERY INDICATES DEVELOPING CU ALONG A
FRONTAL BOUNDARY LOCATED OVER THE SOUTHERN TEXAS PANHANDLE DOWN INTO
THE LOW ROLLING PLAINS. DEVELOPING CU WERE ALSO NOTED ACROSS MUCH OF
THE TX PANHANDLE WHERE TEMPERATURES HAVE WARMED INTO THE UPPER 70S TO
AROUND 80 DEGREES. A MOIST AND UNSTABLE AIR MASS LIES ACROSS THIS
AREA WITH SBCAPES BETWEEN 1500- 2500 J/KG. WHILE 0-6 KM BULK SHEAR
FROM SPC RUC MESOSCALE ANALYSIS IS NOT AT ALL IMPRESSIVE...GIVEN THE
MOIST AND UNSTABLE AIR MASS...IF ANY STORMS WERE TO DEVELOP THEY CAN
BECOME SEVERE. FURTHER NORTH ACROSS THE OK PANHANDLE...LOW CLOUDS
HAVE BEEN SLOW TO ERODE KEEPING THIS AREA UNDER A COOLER AND MORE
STABLE AIR MASS. NONETHELESS DESPITE NOT HAVING MUCH IN THE WAY OF
FORCING MECHANISMS TO INITIATE CONVECTION...MODELS INDICATE ISOLATED
DEVELOPMENT THIS EVENING WITH GREATER CHANCE FOR STORMS LATE
TONIGHT/EARLY WEDNESDAY AS CONVECTION FORMING ON THE HIGHER TERRAIN
OUT WEST...NEAR THE DRYLINE...PUSHES EASTWARD. IN ADDITION...A LOW-
LEVEL JET WILL STRENGTHEN TONIGHT WHICH MAY HELP TO GENERATE
ADDITIONAL STORMS.
UPPER-LEVEL RIDGE GETS SHUNTED FURTHER TO THE EAST WEDNESDAY AS AN
UPPER-LEVEL TROUGH DIGS INTO THE INTERMOUNTAIN WEST. PROSPECTS FOR
STORMS AND HENCE SEVERE WEATHER LOOK BETTER ON WEDNESDAY AS A VORT
MAX MOVES ACROSS THE PANHANDLES. STORMS WILL DEVELOP NEAR THE
DRYLINE IN EASTERN WHERE THEY CAN CONGEAL INTO A LINE OF STORMS THAT
WILL PUSH SOUTHEAST ACROSS THE PANHANDLES. AGAIN CONTINUED SOUTHEAST
SURFACE FLOW WILL MAINTAIN AMPLE LOW-LEVEL MOISTURE WITH AN
UNSTABLE AIR MASS IN PLACE. LARGE HAIL AND DAMAGING WINDS WILL BE
THE PRIMARY HAZARDS WITH THESE STORMS.
THE UPPER TROUGH WILL FURTHER DIG INTO THE NORTHERN ROCKIES THURSDAY
HELPING TO TRANSITION THE UPPER FLOW TO THE SOUTHWEST. A SURFACE
LEE SIDE TROUGH WILL DEEPEN ACROSS THE WESTERN HIGH PLAINS WHICH
WILL CAUSE WINDS TO PICK UP DURING THE DAY. THE DRYLINE WILL ALSO
SURGE INTO THE EASTERN ZONES...WHERE IT WILL FOCUS A CHANCE FOR
SHOWERS AND THUNDERSTORMS EAST OF THE DRYLINE WHERE WARM...MOIST...
AND UNSTABLE CONDITIONS WILL EXIST. FRIDAY LOOKS TO BE SIMILAR
ALTHOUGH EXPECT THE DRYLINE TO PUSH FURTHER EAST...WHICH SHOULD
SHUNT ANY PRECIP CHANCES OUT OF THE AREA. A LOW WILL CLOSE OFF ALONG
THE SOUTHERN PERIPHERY OF THIS BROAD UPPER TROUGH WHERE IT WILL
MOVE ACROSS THE FOUR CORNERS REGION OVER THE WEEKEND AND INTO EARLY
NEXT WEEK. BOTH THE 12Z ECMWF AND GFS HAVE COME IN DRIER WITH ANY
PRECIP CHANCES WITH THIS SYSTEM...SO HAVE CONTINUED WITH A DRY
FORECAST. ALTHOUGH A COLD FRONT WILL PUSH ACROSS THE AREA ON
MONDAY...USHERING IN COOLER TEMPERATURES.
CLK
&&
.FIRE WEATHER...
SHOWERS AND THUNDERSTORMS ARE POSSIBLE TONIGHT THROUGH WEDNESDAY
NIGHT ACROSS THE TX/OK PANHANDLES...HELPING TO MITIGATE THE FIRE
WEATHER THREAT. A DRYLINE WILL PUSH INTO THE EASTERN TX/OK
PANHANDLE THURSDAY THROUGH SATURDAY. GUSTY SOUTHWEST WINDS WILL
DEVELOP BEHIND THE DRYLINE AND ANY ELEVATED OR CRITICAL FIRE
WEATHER CONDITIONS HINGE UPON HOW MUCH PRECIP THE AREA RECEIVES
BEFORE THEN. SHOWERS AND THUNDERSTORMS ARE POSSIBLE THURSDAY AHEAD OF
THE DRYLINE. A COLD FRONT WILL PUSH ACROSS THE PANHANDLES MONDAY.
COOLER AIR BEHIND THE FRONT SHOULD KEEP MINIMUM RELATIVE HUMIDITIES
ABOVE 20 PERCENT.
CLK
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 54 72 54 83 49 / 40 40 50 10 10
BEAVER OK 54 60 55 81 52 / 40 40 40 30 10
BOISE CITY OK 53 59 50 81 42 / 40 40 30 10 10
BORGER TX 57 70 56 84 54 / 40 40 50 20 10
BOYS RANCH TX 56 77 54 85 46 / 40 40 40 10 10
CANYON TX 55 75 54 83 46 / 40 30 50 10 10
CLARENDON TX 54 72 57 84 57 / 30 30 50 20 10
DALHART TX 52 72 45 84 40 / 40 40 40 5 10
GUYMON OK 54 58 52 83 49 / 40 40 40 20 10
HEREFORD TX 55 74 53 81 45 / 30 30 50 10 10
LIPSCOMB TX 54 62 58 78 57 / 40 40 50 30 20
PAMPA TX 55 70 54 79 55 / 40 40 50 20 10
SHAMROCK TX 57 70 60 79 59 / 30 30 50 20 20
WELLINGTON TX 57 76 60 82 59 / 30 30 50 20 20
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
11/05
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
326 PM CDT TUE APR 10 2012
.SHORT TERM...
STILL WATCHING NEAR TERM THUNDER CHANCES. CU FIELDS DEVELOPING
ALONG QUASI-STATIONARY BOUNDARY ROUGHLY FROM AMARILLO TO FLOYDADA
TO GUTHRIE...ALONG THE DRYLINE ABOUT 30 MILES INTO ERN NM...AND IN
AN AREA OF UPSLOPE FLOW FROM CLOVIS NEWD TOWARD AMARILLO. HAVE
ALSO SEEN SOME STORMS DEVELOP ON THE SACRAMENTOS OF CENTRAL
NM...BUT THEY WILL HAVE SOME DISTANCE TO COVER BEFORE THREATENING
THE FCST AREA. UNCERTAIN HOW SUCCESSFUL ANY OF THESE BOUNDARIES
WILL BE. 18Z NAM HAS TRENDED DRIER FAVORING THE SRN PANHANDLE THEN
THE NERN ZONES AS THAT ACTIVITY ROLLS SEWD. HRRR CONTINUES TO BE
RATHER DRY GENERALLY FAVORING HIGH BASED STORMS NEAR THE DRYLINE
WITH POSSIBILITY OF SOME INITATION ACROSS THE SWRN PANHANDLE
SIMILAR TO THE NAM. PROBLEM WITH THE DRYLINE STORMS IS HOW MUCH
DRY AIR HAS MIXED TO THE SFC EAST OF IT WITH LOWER TO MIDDLE 40S
DEW POINTS ACROSS THE WRN FCST AREA. BEST OBVIOUS LOW LEVEL
SUPPORT IS ACROSS THE BOUNDARY LYING ACROSS THE ERN HALF OF THE
FCST AREA WHERE LOW LEVEL INSTABILITY IS THE GREATEST AND THE
BOUNDARY SEEMS TO BE DOING A DECENT JOB OF SERVING AS A
CONVERGENCE ZONE. HOWEVER...THIS IS THE LEAST FAVORED AREA BY THE
MODELS. MEANWHILE THE AREA FAVORED BY THE MODELS SEEMS TO HAVE
LITTLE GOING FOR IT. MUST ALSO NOTE THE UPPER RIDGE OVER THE
ROCKIES THAT IS PROGGED TO DRIFT EWD TONIGHT...ALTHOUGH THAT
FEATURE IS NOT SHUTTING OFF TSRA OVER THE NM MOUNTAINS. THAT SAID
CONFIDENCE NOT HIGH. HAVE GENERALLY KEPT POPS CLOSE TO PREVIOUS
FCST OR LOWERED IN A FEW CASES. POTENTIAL FOR SVR WILL CONTINUE
WITH WIND FAVORED IN THE DRY AIR ACROSS THE WEST AND POTENTIAL FOR
HAIL SHOULD ANY STORMS INITIATE IN THE EAST. TEND TO FAVOR THE NAM
AND ECMWF SOLUTIONS REGARDING A DECREASE IN COVERAGE AFTER
MIDNIGHT.
FOR WEDNESDAY MODELS CONTINUE TO ADVERTISE PRECIP POTENTIAL MAINLY
ACROSS THE WRN HALF DURING THE AFTN. HOWEVER...SEEING NEGATIVES
THERE AS WELL WITH PROGGED THICK CIRRUS AND THE AFOREMENTIONED
UPPER RIDGE HAVING MIGRATED OVERHEAD...ALBEIT WEAKENING WITH A
SERIES OF SHORT WAVE TROUGHS ATTEMPTING TO BREAK IT DOWN. PROGGED
INITATION NEAR AND EAST OF THE DRYLINE SEEMS REASONABLE ALTHOUGH
PROGGED QPF COVERAGE SEEMS A BIT MUCH INITIALLY. HAVE KEPT
PREVIOUS IDEA FAVORING THE WRN ZONES NEAR THE DRYLINE BUT TWEAKED
POPS DOWN A FRACTION.
BOTH FLAVORS OF MOS GUIDANCE FOR OVERNIGHT LOWS AND WEDNESDAY
HIGHS ARE CLOSE TO EACH OTHER AND TO PREVIOUS FCST. NO SIGNIFICANT
ADJUSTMENTS NECESSARY.
&&
.LONG TERM...
SCATTERED CONVECTION NEAR THE NM/TX BORDER LATE WED AFTN EXPECTED TO
ONCE AGAIN SPREAD EASTWARD THRU MUCH OF THE CWFA THRU THE EVENING.
SEVERE POTENTIAL STILL LOOKS BEST ACRS THE WESTERN HALF OF THE AREA
IN CLOSER PROXIMITY OF ENHANCED UPPER LIFT AND INCREASED SHEAR.
COULD STILL THE POTENTIAL FOR TSTM ACTIVITY TO POSSIBLY FORM INTO
SMALL MCS THROUGHOUT THE EVENING AS H85 WINDS RAMP UP TO NEAR 40KTS.
GIVEN STEEP LAPSE RATES OUT WEST...INITIAL SVR THREAT WILL BE LARGE
HAIL AND ISOLATED STRONG WINDS. IF MCS CAN DEVELOP...SVR THREAT WILL
TRANSFORM INTO MORE OF A WIND EVENT THROUGHOUT THE EVENING.
BY THURSDAY...THE BROAD UPPER TROUGH OUT WEST WILL CONTINUE TO
SLOWLY TRANSLATE EASTWARD INTO THE PLAINS. AS THIS OCCURS...THE SFC
TROUGH/DRYLINE WILL SHIFT EAST TO NEAR THE CAPROCK ESCARPMENT BY THE
MID AFTN HOURS. STRONG SFC HEATING COUPLED WITH MODERATE INSTABILITY
AND SHEAR WILL SUPPORT A GOOD THREAT OF SEVERE WX ONCE STORMS FORM.
THESE PARAMETERS SHOULD ALSO LEAD TO A BETTER CHANCE OF DISCRETE
SUPERCELLS ALONG AND JUST EAST OF THE DRYLINE.
AS THE UA TROUGH CONTINUES TO HEAD EAST ON FRIDAY...THE CHANCE FOR
PRECIPITATION ACRS THE ROLLING PLAINS WILL DWINDLE AS THE DRYLINE
NEARS THE EASTERN EDGE OF THE CWFA. WILL RETAIN JUST A VERY SLIGHT
MENTION OF STORMS ACRS THIS VCNTY FOR BOTH THE FRIDAY AND SATURDAY
LATE AFTN/EARLY EVE TIME FRAMES.
DRY AND WINDY WEATHER APPEARS IN STORE FOR THE WEEKEND AS THE CLOSED
H5 LOW HEADS THROUGH THE FOUR CORNERS REGION AND THEN BEGINS TO LIFT
MORE TO THE NORTHEAST INTO MONDAY. AS STATED BY PREVIOUS
SHIFT...STRONGEST WINDS SHOULD OCCUR ON SATURDAY AS MID LEVEL JET
STREAK ADVANCES INTO WEST TEXAS AROUND BASE OF UPR TROUGH. THIS WILL
LEAD TO ELEVATED FIRE WEATHER CONDITIONS ON SATURDAY AND PERHAPS
SUNDAY AS WELL WITH LOW RH/S IN PLACE.
INCONSISTENCIES IN THE LONG RANGE MODELS CONTINUE TO PERSIST FOR
EARLY NEXT WEEK MAINLY IN REGARD TO HOW FAST THE THE UPPER TROUGH
EJECTS NORTHEAST OF THE REGION AND ALLOWS A COLD FRONT TO SLIP SOUTH
INTO THE AREA. FOR NOW...WILL KEEP ARRIVAL OF FRONT ON MONDAY WITH
SLIGHTLY BELOW COOLER TEMPS FOR MON AND TUES.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 55 74 53 80 45 / 40 50 50 10 10
TULIA 56 79 55 82 53 / 40 40 50 10 10
PLAINVIEW 57 79 56 84 54 / 50 30 50 10 10
LEVELLAND 58 78 56 82 54 / 40 40 50 10 10
LUBBOCK 59 79 59 83 57 / 40 30 50 20 20
DENVER CITY 58 79 57 84 54 / 30 40 40 10 10
BROWNFIELD 59 79 57 83 56 / 30 40 40 10 10
CHILDRESS 58 79 60 83 60 / 50 20 40 20 20
SPUR 59 81 59 83 58 / 40 20 40 20 20
ASPERMONT 60 83 62 84 62 / 30 20 40 20 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07/21
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1231 PM CDT TUE APR 10 2012
.AVIATION...
MAIN FORECAST CONCERN IS CONVECTIVE POTENTIAL LATE THIS AFTERNOON
AND EARLY EVENING AS WEAK FRONT MOVES INTO THE REGION FROM THE
NORTHEAST. AIR MASS SHOULD BE UNSTABLE/UNCAPPED FOR
CONVECTION...HOWEVER THE FRONT/FOCUS FOR CONVECTION SHOULD STAY
NORTHEAST OF TAF SITES. RUC IS PARTICULARLY AGGRESSIVE WITH
CONVECTION THIS EVENING...DRIVING A STRONG OUTFLOW BOUNDARY AND
CONVECTION IN FROM THE NORTHEAST. SO FAR THIS SOLUTION HAS LITTLE
SUPPORT FROM THE OTHER MODELS. WILL MONITOR TRENDS CLOSELY FOR
INCLUSION OF VCTS BETWEEN 23-2Z...BUT BELIEVE CONVECTION WILL STAY
SCATTERED AND LOOSELY ORGANIZED TO THE NORTHEAST OF TAF SITES.
OTHERWISE LIGHT SW WINDS THIS AFTERNOON SHOULD BECOME SE THIS
EVENING. LIGHT WINDS SHOULD RESULT IN SOME LIGHT BR/HZ WEDNESDAY
MORNING BUT OTHERWISE LOW LEVEL MOISTURE LOOKS TOO DRY AND LOW
LEVEL JET TOO WEAK FOR MVFR CIGS...AND THUS HAVE REMOVED THAT
MENTION FROM THE TAFS.
TR.92
&&
.UPDATE...
THICK HIGH CLOUDS CONTINUE TO CLEAR FROM NORTHWEST TO SOUTHEAST
ACROSS NORTH TEXAS...GIVING WAY TO MOSTLY SUNNY SKIES ACROSS THE
NORTHERN HALF OF THE AREA. IT ALSO APPEARS THAT ANY FOG THAT HAD
FORMED OVERNIGHT HAS COMPLETELY ERODED OVER THE PAST FEW HOURS. THIS
TREND SHOULD ALLOW TEMPERATURES TO WARM TO NEAR FORECAST HIGHS OF
THE MID 80S ACROSS MOST OF THE REGION.
ISOLATED STORMS SHOULD FORM NEAR THE RED RIVER ALONG A WEAK
SURFACE FRONT BY MID AFTERNOON...AND PROPAGATE SOUTHEAST BOTH
ALONG AN AXIS OF HIGHER MOISTURE AND INSTABILITY AND IN THE
GENERAL NORTHWEST FLOW ALOFT. AT THIS TIME IT LOOKS LIKE THE BEST
CHANCES FOR PRECIP WILL BE NORTH AND EAST OF THE METROPLEX...AND
HAVE ADJUSTED POPS ACCORDINGLY FOR THE AFTERNOON. WILL LEAVE POPS
AS IS FOR TONIGHT WITH THE THOUGHT THAT THE WEAK FRONT WILL
BACKDOOR ITS WAY INTO THE AREA AND PROVIDE FOCUS FOR A FEW SHOWERS
OR STORMS OVERNIGHT. WILL ASSESS THE SITUATION IN BETTER DETAIL FOR
THE AFTERNOON PACKAGE AS THE LATEST MODEL DATA ARRIVES.
30
&&
.PREV DISCUSSION... /ISSUED 431 AM CDT TUE APR 10 2012/
REGIONAL RADARS INDICATE TWO CLUSTERS OF CONVECTION TO THE WEST OR
NORTHWEST OF THE CWA AT THE TIME OF THIS DISCUSSION. THE CLOSEST
CLUSTER...NEAR WICHITA FALLS AT 330 AM CDT...IS THE MOST LIKELY TO
AFFECT NORTHWEST PORTIONS OF THE CWA THIS MORNING. LIGHTNING
FREQUENCY HAS BEEN DIMINISHING WITHIN THIS CLUSTER OF STORMS OVER
THE PAST 30 MINUTES...SO DO NOT ANTICIPATE THESE STORMS HOLDING
TOGETHER VERY LONG ONCE MOVING INTO NORTH TX. THE SECOND CLUSTER
OF STORMS WAS LOCATED NEAR SWEETWATER AT 330 AM CDT AND THIS
CLUSTER WAS ALSO MOVING SOUTHEAST. IF THIS ACTIVITY HOLDS
TOGETHER IT LOOKS AS THOUGH IT WILL SKIRT THE MILLS/SAN SABA
COUNTY LINE...HOLDING JUST TO THE SOUTHWEST OF THE CWA THIS
MORNING. WITH THIS IN MIND ONLY MAINTAINED 20 POPS ACROSS THE
NORTHWESTERN HALF OF THE CWA AFTER SUNRISE WITH SOMEWHAT LOW
CONFIDENCE IN CURRENT ACTIVITY HOLDING TOGETHER AND MOVING OVER
THE CWA AFTER 12Z/7AM CDT. WILL CONTINUE TO MONITOR THE EVOLUTION
OF THESE TWO AREAS OF CONVECTION AND UPDATE THE FORECAST IF THERE
IS ANY SIGNIFICANT CHANGES IN THE INTENSITY OR TRACK OF THIS
ACTIVITY.
TODAY...OUTSIDE OF THE POTENTIAL FOR MORNING THUNDERSTORM ACTIVITY
TO AFFECT PORTIONS OF NORTH TX...THINK THAT MOST AREAS WILL
REMAIN DRY DURING THE DAYLIGHT HOURS. MAINTAINED 20 POPS FOR AREAS
ALONG AND NORTH OF A CISCO TO DENTON TO SULPHUR SPRINGS LINE TO
ACCOUNT FOR SMALL THUNDERSTORM CHANCES ASSOCIATED WITH SUBTLE
BOUNDARIES LEFT OVER FROM CONVECTION THIS MORNING. OVERALL A LACK
OF STRONG FORCING FOR ASCENT PRECLUDES MENTION OF HIGHER POPS AT
THIS TIME. ONCE AGAIN THINK THAT THE BEST PRECIPITATION CHANCES
FOR NORTH TX WILL COME FROM UPSTREAM CONVECTION MOVING SOUTHEAST
IN THE NORTHWEST STEERING WINDS ALOFT.
MOST GUIDANCE ONCE AGAIN DEVELOPS CONVECTION ALONG A QUASI-
STATIONARY BOUNDARY EXTENDING FROM THE TX PANHANDLE SOUTHEAST THRU
CENTRAL OK AND INTO THE ARKLATEX REGION. WITHOUT ANY SIGNIFICANT
CHANGE IN AIRMASS FROM YESTERDAY THINK THAT MODEL FORECAST
INSTABILITY IN THE 1500 TO 2000 J/KG RANGE IS REASONABLE AND
SHOULD SUPPORT SOME ORGANIZED CONVECTIVE MODE UPSTREAM THIS
AFTERNOON. ONCE AGAIN IF THIS ACTIVITY CAN GROW UPSCALE INTO A
LINEAR MCS IT WILL LIKELY MOVE SOUTHEAST AND AFFECT NORTH TX AFTER
SUNSET. AS A RESULT PLACED THE BEST CHANCE FOR STORMS FOR AREAS
ALONG AND NORTHEAST OF A BOWIE TO FORT WORTH TO PALESTINE LINE FOR
TUESDAY EVENING AND OVERNIGHT DUE TO THE POTENTIAL FOR HIGH PLAINS
CONVECTION TO SLIDE SOUTHEAST OVER THE CWA AFTER SUNSET. BECAUSE
CONVECTION IS MOST LIKELY TO MOVE OVER NORTH TX AFTER SUNSET...THE
BIGGEST THREATS ASSOCIATED WITH THIS ACTIVITY WILL BE LARGE HAIL
AND LOCALLY HEAVY RAINFALL. DAMAGING WIND IS CERTAINLY
POSSIBLE...BUT THIS SHOULD BE AN ISOLATED THREAT UNLESS A STRONG
MCS IS ABLE TO ORGANIZE UPSTREAM.
WEDNESDAY...GUIDANCE INDICATES THAT A STRONG SHORTWAVE TROUGH WILL
MOVE OVER THE SOUTHWESTERN CONUS WEDNESDAY AFTERNOON WHICH WILL
CAUSE UPPER RIDGING CURRENTLY IN PLACE OVER THE SOUTHERN ROCKIES
TO FLATTEN OUT WHILE MOVING EAST OVER THE SOUTHERN PLAINS. AT THE
SAME TIME MOST GUIDANCE AGREES THAT A STRONG SHORTWAVE TROUGH WILL
DIVE SOUTHEAST OVER THE OHIO AND TENNESSEE VALLEYS. THIS
TROUGH...WHICH WOULD NORMALLY HAVE NO IMPACT ON OUR REGIONAL
WEATHER PATTERN...IS EXPECTED TO PLAY A ROLE IN DRIVING SURFACE
RIDGING SOUTH THROUGH THE MISSOURI AND MISSISSIPPI RIVER VALLEYS
WEDNESDAY AFTERNOON. ASSUMING THIS PANS OUT...THE STRONGER SURFACE
RIDGE MOVING SOUTHEAST SHOULD CAUSE THE QUASI-STATIONARY BOUNDARY
IN PLACE OVER OKLAHOMA TO SINK SOUTHWEST AS A BACK DOOR TYPE COLD
FRONT WEDNESDAY AFTERNOON. COOLER AIR MOVING SOUTH WITH THE
SURFACE RIDGE SHOULD HELP TO STEEPEN LOW LEVEL ISENTROPIC SURFACES
AND INCREASE LOW LEVEL FRONTOGENETIC FORCING ALONG AND NORTHEAST
OF THE FRONT. DESPITE RIDGING ALOFT...THIS RELATIVELY STRONG LOW
LEVEL FORCING MAY BE SUFFICIENT FOR THE INITIATION OF SCATTERED
THUNDERSTORM ACTIVITY WEDNESDAY AFTERNOON ALONG AND NORTHEAST OF
THE FRONT. WENT AHEAD WITH SOME LOWER CHANCE POPS TO ACCOUNT FOR
THIS POSSIBILITY GENERALLY NORTHEAST OF THE METROPLEX.
FOR WEDNESDAY NIGHT MAINTAINED A CHANCE OF THUNDERSTORM ACTIVITY
OVER THE WESTERN HALF OF THE FORECAST AREA AS THUNDERSTORMS WILL
LIKELY FIRE UP ALONG THE DRYLINE OVER WEST TX WEDNESDAY AFTERNOON.
WITH SOMEWHAT FLAT/ZONAL FLOW PROGGED TO EXIST UNDER THE SOUTHERN
PORTIONS OF THE UPPER RIDGE...EXPECT THAT ANY ORGANIZED
THUNDERSTORM ACTIVITY WOULD TEND TO MOVE EAST TOWARDS NORTH TX
AFTER SUNSET. EXPECT THAT ACTIVITY WOULD TEND TO DISSIPATE AFTER
MIDNIGHT MOVING INTO A LESS UNSTABLE AIRMASS AND WITH WEAK RIDGING
ALOFT.
THURSDAY AND FRIDAY...THE UPPER LEVEL FLOW REGIME IS EXPECTED TO
TRANSITION TO SOUTHWEST FLOW ALOFT AS A LARGE UPPER LOW MOVES IN
PLACE OVER THE WESTERN CONUS. ALL GUIDANCE IS IN LINE WITH THIS
SOLUTION SO CONFIDENCE IS FAIRLY HIGH WITH REGARDS TO THIS CHANGE
IN LARGE SCALE FLOW. CONFIDENCE IS SOMEWHAT LOWER REGARDING THE
TIMING AND PLACEMENT OF INDIVIDUAL PIECES OF ENERGY (SHORTWAVE
TROUGHS) ROTATING AROUND THIS LARGE UPPER LOW THRU THE PERIOD. AT
THIS TIME THE CONSENSUS OF VARIOUS OPERATIONAL MODELS IS THAT
SHORTWAVE ENERGY WILL REMAIN TOO FAR NORTHWEST OF THE CWA TO
PROVIDE MUCH IN THE WAY OF FORCING FOR ASCENT FOR THUNDERSTORM
ACTIVITY DURING THIS PERIOD. THE DRYLINE AND SYNOPTIC WARM/QUASI-
STATIONARY BOUNDARY ARE EXPECTED TO REMAIN OUT OF NORTH TX AS WELL
FROM THURSDAY THROUGH FRIDAY FURTHER LOWERING CONFIDENCE THAT WE
WILL SEE ANY FOCUSED LIFT FOR THUNDERSTORM INITIATION DURING THE
PERIOD. RICH GULF MOISTURE IS EXPECTED TO REMAIN IN
PLACE...HOWEVER THE SOUTHWEST FLOW ALOFT IS EXPECTED TO ADVECT A
STRONG ELEVATED MIXED LAYER (EML) CAP OVER NORTH TX. WHILE THE EML
WILL HELP TO BUILD UP CONVECTIVE POTENTIAL ENERGY PARAMETERS...IN
THE ABSENCE OF LIFT THINK THAT THIS CAP WILL BE PROHIBITIVE FOR
THUNDERSTORM INITIATION AND WENT WITH A DRY FORECAST AS A RESULT.
SATURDAY THROUGH MONDAY...MOST GUIDANCE INDICATES THAT A STRONG
SHORTWAVE TROUGH WILL EJECT NORTHEAST OVER THE SOUTHERN HIGH
PLAINS ON SATURDAY BEFORE THE LARGE WESTERN CONUS UPPER LOW BEGINS
TO MOVE SOUTHEAST OVER THE SOUTHERN PLAINS FOR SUNDAY OR MONDAY.
WITH RICH GULF MOISTURE UNDER A PLUME OF STEEP MID-LEVEL LAPSE
RATES ASSOCIATED WITH THE EML THERE WILL LIKELY BE AT LEAST
MODERATE INSTABILITY IN PLACE OVER NORTH TX FOR MUCH OF THE
PERIOD. WITH THE UPPER LOW FINALLY MOVING OUT OF THE WESTERN CONUS
DEEP LAYER SHEAR VALUES ARE EXPECTED TO INCREASE SUBSTANTIALLY
DURING THE PERIOD. THIS IS EXPECTED TO SET THE STAGE FOR A COUPLE
OF SEVERE THUNDERSTORM EPISODES ACROSS THE REGION.
PRECIPITATION CHANCES ARE MOST LIKELY WHEN THE UPPER LOW PULLS
OUT OVER THE REGION ON EITHER SUNDAY OR MONDAY. WITHOUT GREAT
CONFIDENCE AS TO WHEN THIS WILL OCCUR WENT AHEAD WITH BROAD
BRUSHED 30 POPS FOR THE CWA ON SUNDAY AND MONDAY. FOR SATURDAY
MOST AFTERNOON THUNDERSTORM ACTIVITY IS EXPECTED TO REMAIN WEST OF
THE CWA...HOWEVER THE GOOD COMBINATION OF CAPE AND SHEAR MAKES
UPSCALE CONVECTIVE GROWTH MORE LIKELY SATURDAY EVENING AND
OVERNIGHT. THIS COULD LEAD TO A FAIRLY WELL ORGANIZED MCS MOVING
INTO THE WESTERN CWA SATURDAY EVENING. BECAUSE THIS IS MORE OF A
MESOSCALE CONCERN...BY DEFINITION CONFIDENCE IN SOMEWHAT LOW IN
EXACTLY HOW THINGS WILL EVOLVE ON SATURDAY. REGARDLESS...THE
PATTERN LOOKS SUPPORTIVE FOR THUNDERSTORM CHANCES ACROSS THE
WESTERN CWA SATURDAY NIGHT AND HAVE OUR BEST POPS WEST OF
INTERSTATE 35 AS A RESULT. THUNDERSTORM ACTIVITY IS EXPECTED TO
CLEAR THE REGION MONDAY NIGHT.
CAVANAUGH
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 84 63 81 59 75 / 20 30 10 30 10
WACO, TX 83 58 81 61 78 / 10 20 10 30 10
PARIS, TX 82 59 73 51 70 / 20 40 30 20 10
DENTON, TX 85 61 81 57 75 / 20 30 20 30 10
MCKINNEY, TX 84 61 79 56 75 / 20 40 20 30 10
DALLAS, TX 84 64 81 60 76 / 20 30 10 30 10
TERRELL, TX 83 61 80 57 76 / 10 30 10 20 10
CORSICANA, TX 83 61 81 60 77 / 10 20 10 20 10
TEMPLE, TX 83 58 80 62 79 / 10 10 10 20 10
MINERAL WELLS, TX 85 59 82 58 78 / 20 20 10 30 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1148 PM CDT MON APR 9 2012
.UPDATE...
UPDATED FOR 06Z AVIATION DISCUSSION.
&&
.AVIATION.../06Z TAFS/
FOR KAMA...VFR CONDITIONS WILL CONTINUE THROUGH AROUND 09Z BEFORE
LOW STRATUS CLOUDS...IFR/LIFR CEILINGS...DEVELOP WITH WINDS TURNING
TO THE EAST SOUTHEAST AROUND 10KTS. CEILINGS WILL GRADUALLY IMPROVE
AFTER 15Z...WITH VFR RETURNING BY 18Z. DECIDED TO INCLUDE A VCTS
BETWEEN 22Z-02Z AS THIS SHOULD BE THE BEST CHANCE TO SEE TSRA NEAR
THE TERMINAL.
FOR KDHT AND KGUY...LOW STRATUS CLOUDS...IFR/LIFR CEILINGS...WILL
DEVELOP /CONTINUE FOR KGUY/ WITH WINDS TURNING TO THE EAST SOUTHEAST
AROUND 10-15KTS. CEILINGS WILL GRADUALLY IMPROVE AFTER 14Z...WITH VFR
RETURNING BY 19Z. BELIEVE THE BULK OF THE TSRA WILL STAY SOUTH OF
THESE TERMINALS SO HAVE LEFT MENTION OUT AT THIS TIME.
KNS
&&
.DISCUSSION... /ISSUED 1123 PM CDT MON APR 9 2012/
SVR TSTM WATCH 152 HAS EXPIRED AND HAVE UPDATED GRIDS AND PUBLIC
PRODUCTS TO ACCOUNT FOR THIS. ALSO LOWERED POPS A BIT MORE BASED ON
LATEST RADAR TRENDS.
ANDRADE
PREV DISCUSSION... /ISSUED 939 PM CDT MON APR 9 2012/
UPDATE... HAVE CANCELLED PARTS OF SVR TSTM WATCH 152 BASED ON RADAR
TRENDS. STILL A CLUSTER OF STORMS ONGOING IN SERN AND ERN ZONES SO
WILL LEAVE THE WATCH UP FOR THAT AREA TIL EXPIRATION AT 04Z. ALSO
REDUCED POPS ALL ZONES REST OF TONIGHT AS PRECIP COVERAGE CONTINUES
TO DECREASE. UPDATED PRODUCTS AND GRIDS COMPLETED.
ANDRADE
&&
.PREV DISCUSSION.../ISSUED 408 PM CDT MON APR 9 2012/
MAIN FORECAST FOCUS THIS AFTERNOON CENTERS ON SEVERE POTENTIAL THIS
EVENING AND TONIGHT.
AFTERNOON WATER VAPOR SATELLITE IMAGERY SHOWS AN UPPER-LEVEL VORT
MAX CURRENTLY MOVING ACROSS EASTERN NM AND WEST TX. THIS AND
CONVERGENCE ALONG A SURFACE TROUGH OVER THE WESTERN TX PANHANDLE HAS
LED TO SCATTERED STRONG STORMS TO DEVELOP ACROSS THE TX PANHANDLE.
LATEST HRRR GUIDANCE INDICATES THESE STORMS TO CONGEAL INTO A
LINE AND PUSH SOUTHEAST TONIGHT. STEEP MID LEVEL LAPSE RATES...
FAVORABLE BULK SHEER VALUES...AND SBCAPES AROUND 1000-2000 J/KG
WILL MAINTAIN A SEVERE THREAT TONIGHT ALTHOUGH SLIGHTLY DRIER AIR
WAS LOCATED NEAR THE NM BORDER WHERE SURFACE WINDS WERE OUT OF THE
SOUTHWEST. GIVEN THE ISSUANCE OF SEVERE THUNDERSTORM WATCH #152...
HAVE GONE AND INCREASED POPS TONIGHT...ESPECIALLY ACROSS THE
EASTERN ZONES WHERE BETTER LOW LEVEL MOISTURE AND INSTABILITY ARE CO-
LOCATED. IN ADDITION...A PACIFIC FRONT WILL SAG INTO NORTHERN OK
THIS EVENING WHICH WILL ALSO PROVIDE A FOCUS FOR THUNDERSTORM
DEVELOPMENT TONIGHT.
UPPER LEVEL RIDGE WILL MOVE SQUARELY OVER THE CENTRAL/SOUTHERN
PLAINS TUESDAY. WHILE THE UPPER FLOW WILL BE WEAK AND ANY FORCING
FOR ASCENT WILL BE NEGLIGIBLE...SOUTHEAST UPSLOPE FLOW WILL MAINTAIN
A GOOD FETCH OF LOW-LEVEL MOISTURE. THE ATMOSPHERE SHOULD
DESTABILIZE DURING THE AFTERNOON WHICH WILL HELP INITIATE STORMS.
BETTER CHANCES FOR STORMS WILL BE TUESDAY EVENING AS A VORT MAX TOPS
THE RIDGE. THE RIDGE WILL START TO SHIFT OFF TO THE EAST WEDNESDAY
WITH ADDITIONAL UPPER ENERGY TOPPING THE RIDGE. AGAIN THE AREA
REMAINS UNDER A MOIST AND UNSTABLE AIR MASS AND THUS HAVE CONTINUED
WITH THUNDER CHANCES THROUGH WEDNESDAY NIGHT.
AN UPPER-LEVEL TROUGH WILL DIG INTO NORTHERN ROCKIES THURSDAY.
FALLING HEIGHTS OVER THE ROCKIES WILL LEAD TO A SURFACE LOW TO
STRENGTHEN ACROSS EASTERN CO/NM. INCREASING SOUTHWEST FLOW ALOFT
WILL PUSH THE DRYLINE INTO THE EASTERN TX PANHANDLE...FOCUSING
THUNDER CHANCES ACROSS THE EASTERN ZONES. THE UPPER TROUGH WILL
SPLIT INTO TWO CHUNKS BY THE END OF THE WEEK WITH THE NORTHERN
PIECE LIFTING ACROSS THE CENTRAL PLAINS SATURDAY. STRONG SOUTHWEST
UPPER-LEVEL FLOW WILL LIKELY PUSH THE DRYLINE INTO THE EASTERN
ZONES AND HAVE MAINTAINED SLIGHT CHANCE OF STORMS SATURDAY. HAVE
NOT MADE TOO MANY CHANGES TO THE FORECAST BEYOND SATURDAY ALTHOUGH
MEDIUM RANGE MODELS SUGGEST THE SOUTHERN PIECE OF THE UPPER TROUGH
WILL DIG INTO THE FOUR CORNERS REGION SUNDAY. A COLD FRONT WILL PUSH
SOUTH OF THE AREA SUNDAY FOCUSING A CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS NORTH TX. MEDIUM RANGE MODELS SUGGEST A WET
START TO THE NEXT WEEK THOUGH AS DIVERGENCE AHEAD OF THE UPPER LOW
OVER THE FOUR CORNERS REGION CAN GENERATE ANOTHER ROUND OF SHOWERS
AND THUNDERSTORMS. HAVE LEFT THE FORECAST DRY FOR NOW FOR THIS
PERIOD AS WOULD LIKE TO SEE IF THE MODELS ARE CONSISTENT IN THIS
SOLUTION OVER THEIR NEXT SEVERAL RUNS.
CLK
&&
.FIRE WEATHER...
FIRE WEATHER CONCERNS WILL BE LOW THROUGH MID WEEK DUE TO HIGH
ATMOSPHERIC MOISTURE CONTRIBUTING TO CHANCES FOR SHOWERS AND
THUNDERSTORMS. HOWEVER CLOUD-TO-GROUND LIGHTNING STRIKES
FROM THUNDERSTORMS CAN CAUSE FIRE STARTS ESPECIALLY ACROSS THE
WESTERN TEXAS AND OKLAHOMA PANHANDLES WHERE FUELS ARE NOT AS MOIST.
WINDS WILL INCREASE TOWARD THE END OF THE WEEK WHILE A DRYLINE
SURGES INTO THE EASTERN TX PANHANDLE. THIS MAY CREATE CRITICAL FIRE
WEATHER CONDITIONS ACROSS THE WESTERN TX/OK PANHANDLES BUT THIS IS
DEPENDENT ON THE AMOUNT OF RAINFALL THIS AREA RECEIVES EARLIER IN
THE WEEK.
CLK
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS AMARILLO TX
1123 PM CDT MON APR 9 2012
.UPDATE...
SVR TSTM WATCH 152 HAS EXPIRED AND HAVE UPDATED GRIDS AND PUBLIC
PRODUCTS TO ACCOUNT FOR THIS. ALSO LOWERED POPS A BIT MORE BASED ON
LATEST RADAR TRENDS.
ANDRADE
&&
.PREV DISCUSSION... /ISSUED 939 PM CDT MON APR 9 2012/
UPDATE...
HAVE CANCELLED PARTS OF SVR TSTM WATCH 152 BASED ON RADAR TRENDS.
STILL A CLUSTER OF STORMS ONGOING IN SERN AND ERN ZONES SO WILL LEAVE
THE WATCH UP FOR THAT AREA TIL EXPIRATION AT 04Z. ALSO REDUCED POPS
ALL ZONES REST OF TONIGHT AS PRECIP COVERAGE CONTINUES TO DECREASE.
UPDATED PRODUCTS AND GRIDS COMPLETED.
ANDRADE
PREV DISCUSSION... /ISSUED 712 PM CDT MON APR 9 2012/
UPDATE...
UPDATED FOR 00Z AVIATION DISCUSSION.
AVIATION.../00Z TAFS/
FOR KAMA...INCLUDED A VCTS FOR AT LEAST THE NEXT 3 TO 4 HOURS AS
SCATTERED TSRA MOVE CLOSE TO THE KAMA TERMINAL. OUTSIDE OF A TSRA
MOVING OVER THE TERMINAL...VFR CONDITIONS WILL CONTINUE THROUGH
AROUND 10Z BEFORE LOW STRATUS CLOUDS...IFR/LIFR CEILINGS...
DEVELOP WITH WINDS TURNING TO THE EAST SOUTHEAST AROUND 10KTS.
CEILINGS WILL GRADUALLY IMPROVE AFTER 15Z...WITH VFR RETURNING BY
18Z.
FOR KDHT AND KGUY...BELIEVE TSRA ACTIVITY WILL REMAIN SOUTH OF THESE
TERMINALS...SO EXPECT VFR CONDITIONS TO CONTINUE. LOW STRATUS
CLOUDS...IFR/LIFR CEILINGS...WILL DEVELOP WITH WINDS TURNING TO THE
EAST SOUTHEAST AROUND 10-15KTS. CEILINGS WILL GRADUALLY IMPROVE AFTER
14Z...WITH VFR RETURNING BY 17Z.
KNS
DISCUSSION... /ISSUED 408 PM CDT MON APR 9 2012/
MAIN FORECAST FOCUS THIS AFTERNOON CENTERS ON SEVERE POTENTIAL THIS
EVENING AND TONIGHT.
AFTERNOON WATER VAPOR SATELLITE IMAGERY SHOWS AN UPPER-LEVEL VORT
MAX CURRENTLY MOVING ACROSS EASTERN NM AND WEST TX. THIS AND
CONVERGENCE ALONG A SURFACE TROUGH OVER THE WESTERN TX PANHANDLE HAS
LED TO SCATTERED STRONG STORMS TO DEVELOP ACROSS THE TX PANHANDLE.
LATEST HRRR GUIDANCE INDICATES THESE STORMS TO CONGEAL INTO A
LINE AND PUSH SOUTHEAST TONIGHT. STEEP MID LEVEL LAPSE RATES...
FAVORABLE BULK SHEER VALUES...AND SBCAPES AROUND 1000-2000 J/KG
WILL MAINTAIN A SEVERE THREAT TONIGHT ALTHOUGH SLIGHTLY DRIER AIR
WAS LOCATED NEAR THE NM BORDER WHERE SURFACE WINDS WERE OUT OF THE
SOUTHWEST. GIVEN THE ISSUANCE OF SEVERE THUNDERSTORM WATCH #152...
HAVE GONE AND INCREASED POPS TONIGHT...ESPECIALLY ACROSS THE
EASTERN ZONES WHERE BETTER LOW LEVEL MOISTURE AND INSTABILITY ARE CO-
LOCATED. IN ADDITION...A PACIFIC FRONT WILL SAG INTO NORTHERN OK
THIS EVENING WHICH WILL ALSO PROVIDE A FOCUS FOR THUNDERSTORM
DEVELOPMENT TONIGHT.
UPPER LEVEL RIDGE WILL MOVE SQUARELY OVER THE CENTRAL/SOUTHERN
PLAINS TUESDAY. WHILE THE UPPER FLOW WILL BE WEAK AND ANY FORCING
FOR ASCENT WILL BE NEGLIGIBLE...SOUTHEAST UPSLOPE FLOW WILL MAINTAIN
A GOOD FETCH OF LOW-LEVEL MOISTURE. THE ATMOSPHERE SHOULD
DESTABILIZE DURING THE AFTERNOON WHICH WILL HELP INITIATE STORMS.
BETTER CHANCES FOR STORMS WILL BE TUESDAY EVENING AS A VORT MAX TOPS
THE RIDGE. THE RIDGE WILL START TO SHIFT OFF TO THE EAST WEDNESDAY
WITH ADDITIONAL UPPER ENERGY TOPPING THE RIDGE. AGAIN THE AREA
REMAINS UNDER A MOIST AND UNSTABLE AIR MASS AND THUS HAVE CONTINUED
WITH THUNDER CHANCES THROUGH WEDNESDAY NIGHT.
AN UPPER-LEVEL TROUGH WILL DIG INTO NORTHERN ROCKIES THURSDAY.
FALLING HEIGHTS OVER THE ROCKIES WILL LEAD TO A SURFACE LOW TO
STRENGTHEN ACROSS EASTERN CO/NM. INCREASING SOUTHWEST FLOW ALOFT
WILL PUSH THE DRYLINE INTO THE EASTERN TX PANHANDLE...FOCUSING
THUNDER CHANCES ACROSS THE EASTERN ZONES. THE UPPER TROUGH WILL
SPLIT INTO TWO CHUNKS BY THE END OF THE WEEK WITH THE NORTHERN
PIECE LIFTING ACROSS THE CENTRAL PLAINS SATURDAY. STRONG SOUTHWEST
UPPER-LEVEL FLOW WILL LIKELY PUSH THE DRYLINE INTO THE EASTERN
ZONES AND HAVE MAINTAINED SLIGHT CHANCE OF STORMS SATURDAY. HAVE
NOT MADE TOO MANY CHANGES TO THE FORECAST BEYOND SATURDAY ALTHOUGH
MEDIUM RANGE MODELS SUGGEST THE SOUTHERN PIECE OF THE UPPER TROUGH
WILL DIG INTO THE FOUR CORNERS REGION SUNDAY. A COLD FRONT WILL PUSH
SOUTH OF THE AREA SUNDAY FOCUSING A CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS NORTH TX. MEDIUM RANGE MODELS SUGGEST A WET
START TO THE NEXT WEEK THOUGH AS DIVERGENCE AHEAD OF THE UPPER LOW
OVER THE FOUR CORNERS REGION CAN GENERATE ANOTHER ROUND OF SHOWERS
AND THUNDERSTORMS. HAVE LEFT THE FORECAST DRY FOR NOW FOR THIS
PERIOD AS WOULD LIKE TO SEE IF THE MODELS ARE CONSISTENT IN THIS
SOLUTION OVER THEIR NEXT SEVERAL RUNS.
CLK
FIRE WEATHER...
FIRE WEATHER CONCERNS WILL BE LOW THROUGH MID WEEK DUE TO HIGH
ATMOSPHERIC MOISTURE CONTRIBUTING TO CHANCES FOR SHOWERS AND
THUNDERSTORMS. HOWEVER CLOUD-TO-GROUND LIGHTNING STRIKES
FROM THUNDERSTORMS CAN CAUSE FIRE STARTS ESPECIALLY ACROSS THE
WESTERN TEXAS AND OKLAHOMA PANHANDLES WHERE FUELS ARE NOT AS MOIST.
WINDS WILL INCREASE TOWARD THE END OF THE WEEK WHILE A DRYLINE
SURGES INTO THE EASTERN TX PANHANDLE. THIS MAY CREATE CRITICAL FIRE
WEATHER CONDITIONS ACROSS THE WESTERN TX/OK PANHANDLES BUT THIS IS
DEPENDENT ON THE AMOUNT OF RAINFALL THIS AREA RECEIVES EARLIER IN
THE WEEK.
CLK
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
1116 PM CDT MON APR 9 2012
.DISCUSSION...
SEE AVIATION DISCUSSION BELOW...
&&
.AVIATION...
A LINE OF THUNDERSTORMS IS CURRENTLY LOCATED FROM NEAR BROWNFIELD
TO TAHOKA AND MOVING SOUTHEAST. A LOT OF UNCERTAINTY REMAINS ON
HOW FAR SOUTH AND EAST THIS LINE WILL MAKE IT...BUT BELIEVE SOME
CONVECTION MAY MOVE INTO PARTS OF THE BIG COUNTRY AFTER MIDNIGHT.
INCLUDED A VCTS GROUP AT KABI STARTING AT 07Z...AND ENDING AT 10Z.
SOME OF THESE STORMS MIGHT MAKE IT FARTHER SOUTH...BUT CONFIDENCE
IS NOT HIGH ENOUGH TO INCLUDE A MENTION OF THUNDER AT THE OTHER
SITES. LIGHT SOUTH WINDS OVERNIGHT...WILL INCREASE TO 8 TO 12
KNOTS LATE TUESDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 612 PM CDT MON APR 9 2012/
UPDATE...
THUNDERSTORMS CONTINUE TO FIRE ACROSS WEST TX THIS AFTERNOON AND
MAY IMPACT PORTIONS OF THE AREA THIS EVENING. POPS WERE INCREASED
ACROSS THE WEST AND BROUGHT FARTHER SOUTH OVER THE HEARTLAND
TONIGHT IN RESPONSE TO CONVECTIVE TRENDS AND MODEL ANALYSIS. IT
REMAINS TO BE SEEN HOW FAR EAST THE SEVERE THREAT ASSOCIATED
WITH THE WEST TX CONVECTION WILL EXTEND BUT UPON COORDINATION WITH
SPC AND SURROUNDING OFFICES...WE OPTED TO INCLUDE CROCKETT COUNTY
IN A SEVERE THUNDERSTORM WATCH...WITH THE PRIMARY THREAT BEING
LARGE HAIL. SBCAPE VALUES ARE NOT EXTREME PER THE RUC MESOANALYSIS
BUT EFFECTIVE LAYER SHEAR VALUES ARE ADEQUATE TO SUPPORT ORGANIZED
CONVECTION. THE 12Z KMAF SOUNDING SHOWED VERY IMPRESSIVE MID LEVEL
LAPSE RATES SO THE HAIL THREAT WILL BE THE THING TO WATCH
INITIALLY.
TONIGHT...WE EXPECT THE CONVECTION OVER THE PANHANDLE AND WESTERN
OK TO GROW UPSCALE INTO AN MCS...PROPAGATING SOUTHEAST OVERNIGHT.
THIS IS EXPECTED TO AFFECT THE BIG COUNTRY LATER TONIGHT AND INTO
THE EARLY MORNING HOURS. THE MCS IS EXPECTED TO BE IN MORE OF A
DECAYING PHASE AT THAT TIME BUT I INCLUDED THE POTENTIAL FOR
SEVERE WEATHER IN THE FORECAST FOR NOW. THE HI RES CONVECTIVE
MODELS BRING THE PRECIP AS FAR SOUTH AS THE COLORADO RIVER BEFORE
REALLY FALLING APART. THE UPDATED FORECAST PRODUCTS HAVE BEEN
ISSUED.
JOHNSON
AVIATION...
SHOWERS AND THUNDERSTORMS ARE DEVELOPING OVER THE TEXAS SOUTH PLAINS
THIS EVENING. THESE MAY EVENTUALLY DEVELOP INTO A LINE OF
THUNDERSTORMS LATER TONIGHT AND APPROACH OUR NORTHERN AND WESTERN
COUNTIES. A LOT OF UNCERTAINTY REMAINS IN THE EXACT TIMING AND
EVOLUTION OF THESE STORMS...SO FOR NOW HAVE ONLY INCLUDED A VCTS
GROUP AT KABI STARTING AT 06Z. LEFT THUNDER OUT OF THE OTHER TAF
SITES...BUT WILL CONTINUE TO MONITOR THE PROGRESS OF STORMS TO OUR
NORTH AND WEST. SOUTH WINDS WILL BE LIGHT OVERNIGHT...THEN INCREASE
TO 10 TO 14 KNOTS BY LATE MORNING TUESDAY. EXPECT AN INCREASE IN MID
AND UPPER LEVEL CLOUDS TONIGHT AS BLOW OFF FROM THE CONVECTION TO
OUR WEST STREAMS ACROSS THE REGION.
DANIELS
PREV DISCUSSION... /ISSUED 356 PM CDT MON APR 9 2012/
SHORT TERM...
THE MAIN SHORT TERM FORECAST ISSUE IS WITH CHANCE AND PLACEMENT OF
CONVECTION LATE THIS AFTERNOON THROUGH TONIGHT. THE 12Z GFS AND NAM
FAVOR OUR NORTHEASTERN COUNTIES LATER TONIGHT. CONVECTIVE DEVELOPMENT
ACROSS THE TEXAS PANHANDLE INTO WESTERN OKLAHOMA MAY GROW UPSCALE
INTO A CLUSTER OR TWO AND TRACK SOUTH-SOUTHEAST INTO THAT AREA BY
OR SHORTLY AFTER 06Z. CARRYING THE HIGHEST POPS /40-50 PERCENT/
ACROSS THAT AREA. HAVE A SLIGHT CHANCE POP COVERING THE SOUTHERN BIG
COUNTRY AND NORTHWESTERN CONCHO VALLEY...WHERE MORE UNCERTAINTY
EXISTS. VISIBLE AND IR SATELLITE LOOPS SHOW WHAT MAY BE A WEAK
EMBEDDED DISTURBANCE ACROSS SOUTHWESTERN TEXAS...MOVING
EAST-NORTHEAST. WILL MONITOR SATELLITE AND RADAR TRENDS FOR ANY
DEVELOPMENT AS THIS FEATURE TRACKS TOWARD OUR SOUTHWESTERN COUNTIES.
WHILE THE 12Z GFS AND NAM ARE NOT SHOWING MUCH CONVECTIVE
DEVELOPMENT ACROSS WEST TEXAS...THE HRRR AND WRF SHOW CONSIDERABLE
DEVELOPMENT AND INDICATE A POSSIBILITY OF THIS CONVECTION MERGING
WITH THE ABOVE-MENTIONED CLUSTER AS IT TRACKS TOWARD OUR FAR
NORTHERN COUNTIES LATE THIS EVENING/EARLY TONIGHT. FOR NOW...TAKING
A CONSERVATIVE APPROACH WITH POPS...BUT THIS MAY NEED TO BE CHANGED
PENDING EVENING DEVELOPMENT.
OVERNIGHT LOW TEMPERATURES A LITTLE TRICKY AND WILL LIKELY DEPEND ON
EXTENT OF CLOUD COVER. CARRYING LOWS SIMILAR TO LAST NIGHT...AND THE
COOLER /UPPER 50S/ READINGS MAY BE ACROSS OUR HEARTLAND AND NORTHWEST
HILL COUNTRY COUNTIES WHERE CLOUD COVERAGE SHOULD BE LOWEST. MODEL
BOUNDARY LAYER FIELDS LOOK DOUBTFUL FOR LOW CLOUD DEVELOPMENT
OVERNIGHT.
FOR TUESDAY...GIVEN THE PROXIMITY OF OUR AREA TO THE MID/UPPER LEVEL
HEIGHT RIDGE...KEEPING POPS BELOW 15 PERCENT AT THIS TIME. MAY HAVE
AN OUTFLOW BOUNDARY FROM OVERNIGHT CONVECTION SAG ACROSS THE BIG
COUNTRY BY TUESDAY MORNING...BUT CONVERGENCE ALONG THIS BOUNDARY IS
NOT EXPECTED TO BE STRONG.
ANTICIPATE HIGH TEMPERATURES TUESDAY TO BE SIMILAR IF NOT A DEGREE
OR TWO WARMER THAN TODAY...WITH SLIGHTLY WARMER 850 MB
TEMPERATURES.
LONG TERM...
MID/UPPER LEVEL RIDGE AXIS WILL BE OVERHEAD EARLY WEDNESDAY BUT
WILL BEGIN TO BREAK DOWN AND SHIFT EAST OF THE AREA LATE WEDNESDAY
AND WEDNESDAY NIGHT AS A LARGE UPPER LEVEL TROUGH MOVES INTO THE
WESTERN CONUS. SHORT RANGE MODELS INDICATE THE DRYLINE BECOMING
ACTIVE TO OUR WEST WEDNESDAY AFTERNOON AS AN UPPER LEVEL DISTURBANCE
IN THE SOUTHWEST FLOW ALOFT TRAVERSES THE AREA. FAR WESTERN COUNTIES
WILL HAVE THE POTENTIAL TO SEE SEVERE STORMS THROUGH THE EARLY
EVENING HOURS GIVEN DEEP LAYER SHEAR AROUND 40 KT AND A MODERATELY
UNSTABLE AIRMASS. STRENGTHENING LOW LEVEL JET WEDNESDAY EVENING
MAY SUSTAIN CONVECTION INTO MUCH OF THE AREA WITH A LESSENING
SEVERE THREAT AS INSTABILITY WANES. INCLUDED ISOLATED THUNDER
ACROSS FAR WESTERN COUNTIES FOR WEDNESDAY AFTERNOON AND INCREASED
POPS TO CHANCE ALL ZONES WEDNESDAY NIGHT.
THURSDAY THROUGH THE UPCOMING WEEKEND LO0KS UNSETTLED AS WE REMAIN
IN SOUTHWEST FLOW ALOFT THROUGH THE PERIOD. LOOKS LIKE THE POTENTIAL
FOR DRYLINE ACTIVITY THROUGH AT LEAST SATURDAY AS WEAK IMPULSES
MOVE THROUGH THE FLOW ALOFT. GFS/ECMWF SHOW A CLOSED LOW DEVELOPING
OVER AZ/NM ON SATURDAY...TRACKING SLOWLY EAST INTO WEST TEXAS BY
EARLY NEXT WEEK. THIS SYSTEM HAS THE POTENTIAL TO BRING ADDITIONAL
RAINFALL AND POSSIBLE SEVERE WEATHER TO THE AREA THROUGH THE
REMAINDER OF THE EXTENDED PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 61 83 60 81 62 / 30 10 20 10 40
SAN ANGELO 60 85 60 83 63 / 20 10 10 10 40
JUNCTION 58 84 60 82 64 / 10 10 10 10 30
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DANIELS
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
304 PM CDT TUE APR 10 2012
.SHORT TERM...
.TONIGHT AND WEDNESDAY...FORECAST CONFIDENCE MEDIUM.
BROKEN TO OVERCAST STRATOCUMULUS CURRENTLY ACROSS THE AREA. THIS
DECK SUPPORTED BY WEAK INSTABILITY/MOISTURE AROUND 5000 FEET ABOVE
GROUND LEVEL IN RUC FORECAST SOUNDINGS. BACK EDGE OF VORTICITY
MAXIMUM IS EXPECTED TO SHIFT SOUTH INTO THE AREA BY 00Z
WEDNESDAY...THEN SOUTH DURING THE EVENING. DOWNWARD MOTION WITH THIS
FEATURE SHOULD SLOWLY WEAKEN CLOUD COVER THIS EVENING...ESPECIALLY
ACROSS THE WESTERN PORTIONS OF THE FORECAST AREA.
THESE CLOUDS SHOULD LINGER IN THE EAST THIS EVENING...BEFORE FINALLY
MIXING OUT LATE TONIGHT. MAY SEE AREA OF CLOUDS TRY TO HANG ON NEAR
THE LAKE...BUT LATEST RUC SOUNDINGS SUGGEST BULK OF ANY LAKE EFFECT
CLOUDS WOULD STAY OFFSHORE. WESTERN END OF ANOTHER VORTICITY MAXIMUM
MAY BRUSH THE AREA WITH SOME CLOUDS LATER THIS EVENING AS WELL.
BRISK NORTHWEST WINDS WITHIN TIGHT PRESSURE GRADIENT AND GOOD LOW
LEVEL MIXING WILL LINGER UNTIL EARLY EVENING AS WELL. PRESSURE
GRADIENT THEN SLOWLY WEAKENS TONIGHT...BUT SHOULD NOT DECOUPLE.
CLEARING SKIES IN THE WEST SHOULD ALLOW LOWS TO FALL TO 28 DEGREES
FAHRENHEIT OR LOWER...SO WENT WITH A FREEZE WARNING FOR GREEN LAKE
TO ROCK COUNTIES AND WEST FROM 06Z TO 14Z WEDNESDAY. POSSIBLE CLOUDS
AND SLIGHTLY STRONGER WINDS IN THE EAST LEFT MORE UNCERTAINTY FOR
LOWS TO REACH THAT THRESHOLD...SO LEFT THOSE AREAS OUT WITH LOWS IN
THE LOWER 30S.
HIGH PRESSURE MOVES ACROSS THE AREA BY LATE IN THE DAY WEDNESDAY.
THIS FEATURE WILL BRING QUIET WEATHER. SOME DIURNAL CUMULUS MAY
DEVELOP DURING THE AFTERNOON PER FORECAST SOUNDINGS. WINDS WILL
SHIFT ONSHORE NEAR THE LAKE BY AFTERNOON...WHICH SHOULD KEEP HIGHS
IN THE 40S...WITH 50S INLAND PER 925MB TEMPERATURE FIELDS.
.WEDNESDAY NIGHT AND THURSDAY...FORECAST CONFIDENCE...HIGH
THE UPPER RIDGE AXIS OVER THE NORTHERN PLAINS WILL EXTEND FROM
MINNESOTA TO MISSOURI ON THURSDAY. NAM/GFS AND 12Z CRAS ALL TAKES
A WEAK SHORTWAVE ACROSS LOWER MICHIGAN THURSDAY AFTERNOON IN THE
DEPARTING NORTHWEST FLOW. ONLY THE 00Z ECMWF HAS A SHORTWAVE
WEDNESDAY NIGHT ACROSS WISCONSIN.
THE HIGH PRESSURE RIDGE BECOMES CENTERED OVER THE GREAT LAKES ON
THURSDAY. SOME FROST/FREEZING POTENTIAL WEDNESDAY NIGHT. SURFACE
WINDS BECOME LIGHT EAST AND SOUTHEAST DURING THE EVENING. HOWEVER
THE NAM THEN SETS UP A SLIGHT LAND BREEZE LATE WEDNESDAY NIGHT.
THEREFORE THERE WILL BE ONE MORE NIGHT WITH A FROST/FREEZE
POTENTIAL.
.THURSDAY NIGHT AND FRIDAY...FORECAST CONFIDENCE...MEDIUM
ALL MODELS PUSH THE UPPER RIDGE INTO THE WESTERN GREAT LAKES REGION
ON FRIDAY. THE 12Z GFS IS MORE AGGRESSIVE IN TAKING PRECIPITATION
INTO SOUTH CENTRAL WISCONSIN THURSDAY NIGHT. PREFER THE NAM/ECMWF
IN AT BEST REACHING AREAS SOUTHWEST OF MADISON AROUND SUNRISE.
ONLY THE 00Z ECMWF KEEPS THE SHEBOYGAN AREA DRY LATE FRIDAY
AFTERNOON...WITH THE OTHER MODELS BRINGING PRECIPITATION ACROSS
THE FORECAST AREA AS THE 850 MB JET BRINGS 10C 850 MB DEWPOINTS
ACROSS SOUTH CENTRAL WISCONSIN.
THE HIGH PRESSURE RIDGE MOVES OFF TO THE EASTERN GREAT LAKES. THE
GFS IS STILL A LITTLE FASTER IN PUSHING A SURFACE LOW INTO MINNESOTA
WITH THE NAM/ECMWF AND DEGEX ALL SLOWER AND WEAKER AND IS PREFERED.
ELEVATED CAPE OF AROUND 60 J/KG FRIDAY AFTERNOON IF LIFTED FROM 5
THSD FT. PREFER MAINLY RAIN AT THIS POINT WITH LOW THUNDER POTENTIAL.
.LONG TERM...
.SATURDAY THROUGH TUESDAY...FORECAST CONFIDENCE...MEDIUM
BOTH THE 12Z GFS/06Z DGEX AND 00Z ECMWF ESTABLISH A MID/UPPER TROUGH
FROM THE SOUTHWEST U.S. NORTHEAST TO THE NORTHERN PLAINS.
MODELS EVENTUALLY ESTABLISH A ZONAL FLOW ACROSS SOUTHERN CANADA
WITH AN UPPER LOW NEAR NEW MEXICO.
THE 12Z GFS KEEPS THE MAIN MID LEVEL LOW OFF TO THE WEST NEAR FAR
SOUTHWEST NEBRASKA...TUESDAY. THE 00Z ECMWF AND 06Z DGEX PUSHES
THE UPPER LOW A LITTLE FASTER WITH A TROUGH PUSHING TOWARD THE
MISSISSIPPI VALLEY.
PREFER THE SLOWER MOVEMENT OF THE SURFACE LOW ON THE 00Z
ECMWF...REACHING FAR NORTHWEST WISCONSIN LATE SATURDAY NIGHT OVER
THE 12Z GFS...THAT HAS THE LOW REACHING FAR EASTERN QUEBEC. THE
06Z DGEX IS EVEN SLOWER WITH A WEAKER LOW NEAR THE IOWA/MINNESOTA
BORDER.
APPEARS SATURDAY NIGHT WILL HAVE THE HIGHER RAIN CHANCES...WITH
THE RAIN CHANCES CONTINUING THROUGH TUESDAY...BUT MORE IN THE
SLIGHT CHANCE TO CHANCE RANGE.
&&
.AVIATION/00Z TAFS/...
BROKEN TO OVERCAST VFR CUMULUS CLOUDS ARE EXPECTED TO LINGER AT TAF
SITES THROUGH LATE THIS AFTERNOON AND EARLY EVENING AT
MADISON...BEFORE MIXING OUT LATER THIS EVENING. MOSTLY CLEAR SKIES
THEN EXPECTED INTO WEDNESDAY AFTERNOON...WHERE SOME SCATTERED VFR
CUMULUS MAY DEVELOP.
EASTERN TAF SITES SHOULD HAVE BROKEN TO OVERCAST VFR CEILINGS LINGER
INTO EARLY THIS EVENING...THEN SLOWLY SCATTER OUT BY LATER TONIGHT.
SOME MVFR CEILINGS ARE POSSIBLE WITH LAKE EFFECT CLOUDS...THOUGH
THINK MOST OF THESE CLOUDS SHOULD STAY OUT OVER LAKE MICHIGAN.
SCATTERED VFR CUMULUS MAY DEVELOP DURING THE AFTERNOON...THOUGH
EASTERLY FLOW MAY PUSH THESE MORE INLAND.
BRISK NORTHWEST WINDS WILL CONTINUE UNTIL SUNSET...WITH GUSTS UP TO
27 KNOTS. NORTHWEST WINDS WILL BE AROUND 10 KNOTS THROUGH
TONIGHT...THEN VEER NORTH WEDNESDAY AND GRADUALLY WEAKEN. THESE
WINDS WILL VEER NORTHEAST TO EAST AT THE EASTERN SITES WEDNESDAY
AFTERNOON AS WELL.
&&
.MARINE...
SMALL CRAFT ADVISORY FOR BRISK NORTHWEST WINDS AND HIGH WAVES TOWARD
THE OPEN WATERS WILL CONTINUE UNTIL 02Z WEDNESDAY. TIGHT PRESSURE
GRADIENT AND GOOD MIXING OF LOW LEVEL WINDS SHOULD SUPPORT GUSTS TO
30 KNOTS MIXING DOWN TO THE SURFACE UNTIL SUNSET...WITH THE GUSTS
SUBSIDING WITH NIGHTFALL. 3 TO 5 FOOT WAVES LINGER TOWARD THE OPEN
WATERS INTO THE EARLY EVENING...BEFORE SUBSIDING TO 2 TO 4 FEET
LATER THIS EVENING AND OVERNIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...FREEZE WARNING FROM 1 AM TO 9 AM CDT WEDNESDAY FOR WIZ046-047-
056-057-062-063-067>069.
LM...SMALL CRAFT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
TONIGHT/WEDNESDAY AND AVIATION/MARINE...WOOD
WEDNESDAY NIGHT THROUGH TUESDAY...HENTZ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1210 PM CDT TUE APR 10 2012
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
351 AM CDT TUE APR 10 2012
AT 3 AM...CURRENTLY WATCHING THE CLOUDS ACROSS NORTHERN
MINNESOTA...AND NORTHERN AND EASTERN WISCONSIN. OVERALL THE
NAM/WRF AND RUC ARE HANDLING THESE CLOUDS THE BEST...AND THEY ARE
IN GOOD AGREEMENT THAT THESE CLOUDS WILL DRIFT EAST OF THE AREA BY
THE AFTERNOON. THIS IS IN RESPONSE TO THE SURFACE HIGH BUILDING
PUSHING EAST INTO THE FORECAST AREA.
WITH 850 MB TEMPERATURES ABOUT 4C COLDER /AROUND -8C/...HIGH
TEMPERATURES THIS AFTERNOON WILL ONLY CLIMB INTO THE 40S. THIS IS
VERY GOOD AGREEMENT WITH THE CONSALL DATA SET AND ABOUT 5 DEGREE
COOLER THAN THE MOS TEMPERATURES.
FOR TONIGHT...IT LOOKS WE WILL HAVE IDEAL RADIATIVE CONDITIONS
/CLEAR SKIES...LOW DEW POINTS...AND LIGHT WINDS/ FOR TEMPERATURES
TO FALL INTO THE 20S. THERE MAY BE EVEN A FEW TEENS IN THE
CRANBERRY BOGS OF CENTRAL WISCONSIN. AS A RESULT...WE WILL HAVE TO
ISSUE ANOTHER A FREEZE WARNING. TO AVOID ANY CONFUSION...WE PLAN
ON ISSUING THE NEW WARNING AT THE SAME TIME THAT THE OTHER ONE
WILL BE EXPIRING.
ON THURSDAY...THE 10.00Z MODELS ARE MUCH SLOWER AT MOVING THE
UPPER LEVEL RIDGE EAST OF THE AREA. AS A RESULT...THE BEST 925 AND
850 MB MOISTURE TRANSPORT REMAINS WEST OF THE FORECAST AREA. IN
ADDITION...MODEL SOUNDINGS SHOW THAT THERE WILL BE QUITE A BIT OF
DRY AIR ACROSS THE REGION. DUE TO THIS...TOOK OUT THE
PRECIPITATION CHANCES THAT WERE IN THERE FORECAST GRIDS DURING THE
AFTERNOON.
ON THURSDAY NIGHT...THE MODELS ARE CONTINUING TO STRUGGLE ON THE
EASTWARD PROGRESSION OF THE UPPER LEVEL RIDGE THROUGH THE REGION.
AS A RESULT...THERE CONTINUES TO BE TIMING DIFFERENCES OF WHEN THE
PRECIPITATION WILL MOVE INTO THE AREA. THE GFS IS THE FASTEST AND
HAS THE RAIN MOVING INTO THE AREA DURING THE EVENING. BOTH THE GEM
AND NAM/WRF MOVE THE PRECIPITATION INTO THE AREA AFTER MIDNIGHT.
FINALLY...THE ECMWF CONTINUES TO KEEP THE ENTIRE AREA DRY. SINCE
THERE IS STILL A LOT OF UNCERTAINTY...KEPT THE PRECIPITATION
CHANCES MAINLY IN THE 30 TO 50 PERCENT RANGE.
.LONG TERM...FRIDAY THROUGH MONDAY
351 AM CDT TUE APR 10 2012
LIKE THEIR PREDECESSORS...THE 10.00Z MODELS CONTINUE TO SHOW VERY
LITTLE RUN TO RUN CONSISTENCY...SO FORECAST CONFIDENCE IS MUCH
LOWER THAN USUAL.
OVERALL...THE MODELS ARE STILL IN GENERAL AGREEMENT THAT THE
UPPER LEVEL RIDGE WILL MOVE RAPIDLY EAST ACROSS THE AREA BY FRIDAY...
BUT THIS OCCURS A BIT SLOWER THAN WHAT WAS INDICATED EARLIER IN
THE WEEK. AS THIS RIDGE MOVES EAST...A SERIES OF SHORT WAVES EJECT
OUT OF THE WESTERN LONG WAVE TROUGH. THE TIMING OF THESE SYSTEMS
HAVE BEEN SO INCONSISTENT THAT THE PRECIPITATION WAS BROAD
BRUSHED. HOWEVER THIS SET OF MODELS INDICATE THAT THE HIGHER RAIN
CHANCES LOOK TO BE ON FRIDAY NIGHT AND SATURDAY NIGHT. WITH MOST
UNSTABLE CAPES OF 500 TO 1000 J/KG...THERE WILL ENOUGH INSTABILITY
FOR THE DEVELOPMENT OF SOME THUNDERSTORMS TO GO ALONG WITH THE
SHOWERS.
AS WE HEAD INTO EARLY NEXT WEEK...THE MODELS QUICKLY DEVELOP A
SPLIT FLOW. THE SOUTHERN STREAM KEEPS A TROUGH FROM THE CENTRAL
PLAINS INTO THE SOUTHWEST UNITED STATES. MEANWHILE THE NORTHERN
STREAM SYSTEM DIPS DOWN INTO THE NORTHERN GREAT LAKES. THIS WOULD
POTENTIALLY ALLOW ANOTHER COOL CANADIAN HIGH TO MOVE SOUTHWARD
INTO THE UPPER MISSISSIPPI RIVER VALLEY. IT IS THIS TIME PERIOD
WHERE THE CONFIDENCE IS EXTREMELY LOW. MUCH OF THIS HAS TO DEAL
WITH HOW THE MODELS ARE NOT HANDLING A MODERATE TO STRONG MADDEN
JULIAN OSCILLATION /CURRENTLY LOCATED OVER SOUTH AMERICA AND
ATLANTIC/. WITH THE EXCEPTION OF THE JAPANESE METEOROLOGY AGENCY
ENSEMBLE SYSTEM /JMAN/...MOST OF THE GLOBAL MODELS WIPE OUT THIS
MJO RAPIDLY BY EARLY NEXT WEEK. HOWEVER CONSIDERING ITS
STRENGTH...THIS SEEMS RATHER UNLIKELY. AS A RESULT...EXPECT A
BRIEF WARM UP AS WE ENTER PHASE 1 /OVER AFRICA/ BY THIS
WEEKEND...FOLLOWED BY YET ANOTHER COOL DOWN AS THE MJO STARTS INTO
THE WESTERN INDIAN OCEAN /PHASE 2/ BY THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...THIS AFTERNOON THRU WEDNESDAY
1210 PM CDT TUE APR 10 2012
MOISTURE NEAR 850MB WITH DIURNAL WARMING/MIXING AND STEEP LOW LEVEL
LAPSE RATES WILL PRODUCE SCT TO LOCALLY BKN STRATO-CU CLOUDS NEAR 5K
FT AND NORTHWEST WINDS 10-20KT GUSTING 20-26KTS THRU THIS AFTERNOON.
THE PATTERN WILL BE SLOWLY PROGRESSIVE TONIGHT/WED WITH THE SFC-
500MB RIDGE AXIS SHIFTING EAST CLOSER TO THE AREA. SKIES WILL BECOME
CLEAR THIS EVENING WITH LOSS OF DIURNAL WARMING. THE MOISTURE NEAR
850MB WILL BE PUSHED EAST TONIGHT WITH ONLY FEW/SCT 5K FT CUMULUS
EXPECTED WED...MAINLY EAST OF THE MS RIVER. WINDS WILL BE LIGHT
NORTHWEST AFTER SUNSET THIS EVENING...THEN MOSTLY IN THE 6-12KT
RANGE WED AS THE SFC RIDGE AXIS APPROACHES/DRIFTS OVER THE AREA.
&&
.FIRE WEATHER...THROUGH WEDNESDAY
351 AM CDT TUE APR 10 2012
TEMPERATURES WILL BE ANOTHER 5 TO 10 DEGREES COLDER THAN THEY WERE
ON MONDAY AFTERNOON. MEANWHILE THE DEW POINTS WILL BE SIMILAR. AS
A RESULT...THE RELATIVE HUMIDITIES /25 TO 30 PERCENT/ WILL BE A
BIT HIGHER THIS AFTERNOON. THE SUSTAINED WIND SPEEDS WILL BE
SLIGHTLY LOWER /AROUND 20 MPH/ THAN THEY WERE ON MONDAY AFTERNOON
TOO. ALL OF THESE ALONG WITH VERY HIGH TO EXTREME FIRE WEATHER
CONDITIONS WILL LEAD TO ANOTHER CRITICAL FIRE WEATHER DAY /JUST
UNDER RED FLAG WARNING CRITERIA/ FOR TODAY. ANY PLANS FOR OUTDOOR
BURNING SHOULD BE AVOIDED.
ON WEDNESDAY...WE DO NOT MIX QUITE AS DEEP /UP TO 875 MB/ AND THE
DEW POINTS WILL BE SLIGHTLY HIGHER...SO RELATIVE HUMIDITIES WILL
BE CLOSER TO 30 PERCENT. IN ADDITION...THERE WILL BE MUCH LIGHTER
WINDS AS THE HIGH PRESSURE SYSTEM DRIFTS OVERHEAD. WITH LESS WIND
AND SLIGHTLY HIGHER RELATIVE HUMIDITIES...NOT EXPECTING THE RAPID
SPREAD OF ANY FIRES THAT HAPPEN TO DEVELOP.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
259 AM CDT TUE APR 10 2012
WI...FREEZE WARNING UNTIL 10 AM CDT THIS MORNING FOR WIZ017-029-
032>034-041>044-053>055-061.
MN...FREEZE WARNING UNTIL 10 AM CDT THIS MORNING FOR MNZ079-086>088-
094>096.
IA...FREEZE WARNING UNTIL 10 AM CDT THIS MORNING FOR IAZ008>011-018-
019-029-030.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
FIRE WEATHER......BOYNE
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1130 AM CDT TUE APR 10 2012
.UPDATE...BROKEN CUMULUS DEVELOPING ACROSS THE AREA LATE THIS
MORNING...IN AGREEMENT WITH EXPECTED CU RULE VALUES IN THE BROKEN
RANGE. THESE CLOUDS SHOULD LINGER ACROSS THE AREA THROUGH THE
AFTERNOON AND INTO TONIGHT. OVERCAST DECK IN THE FAR NORTHEAST
COUNTIES SHOULD GRADUALLY MIX OUT AND BE REPLACED WITH THE BROKEN
CUMULUS AS WELL. ALREADY SEEING EVIDENCE OF THIS IN LATEST
VISIBLE SATELLITE IMAGERY.
BRISK NORTHWEST WINDS WITHIN TIGHT PRESSURE GRADIENT AND GOOD LOW
LEVEL MIXING WILL LINGER AS WELL THROUGH THE AFTERNOON. 925MB
TEMPERATURES THIS AFTERNOON SUPPORT HIGHS IN THE LOWER 40S...AND
WITH EXPECTED CLOUDS...MAY HAVE TO LOWER HIGH TEMPERATURES A BIT.
ANOTHER CLOUD DECK MAY SWEEP SOUTHWARD THROUGH THE AREA LATER THIS
EVENING AS WELL. SOME LAKE EFFECT CLOUDS MAY ALSO DEVELOP AND MOVE
OVER THE LAKESHORE COUNTIES LATER TONIGHT WITH ONSHORE LOW LEVEL
FLOW AND FAVORABLE DELTA T VALUES. CLOUDS SHOULD GRADUALLY MOVE
OUT FROM WEST TO EAST LATER TONIGHT INTO EARLY WEDNESDAY...AS
DRIER AIR MOVES INTO THE REGION.
LOWS SHOULD FALL INTO THE UPPER 20S ACROSS LOWER CLOUD AREAS IN
THE WESTERN PORTIONS OF THE FORECAST AREA. MAY NEED ANOTHER FREEZE
WARNING FOR THIS AREA. QUIET WEATHER IS EXPECTED WEDNESDAY...AS
HIGH PRESSURE MOVES INTO THE REGION.
&&
.AVIATION/18Z TAFS/...BROKEN VFR CUMULUS CLOUDS ARE EXPECTED TO
LINGER AT TAF SITES THIS AFTERNOON INTO THIS EVENING. MADISON
SHOULD SEE CLOUDS GRADUALLY MOVE OUT LATER TONIGHT...WITH
SCATTERED VFR DIURNAL CUMULUS POSSIBLE ON WEDNESDAY AFTERNOON.
EASTERN TAF SITES SHOULD HAVE VFR CEILINGS LINGER LATER
TONIGHT...WITH SOME MVFR CEILINGS POSSIBLE WITH LAKE EFFECT
CLOUDS. THESE CLOUDS SHOULD MOVE OUT OF THE AREA BY MID MORNING ON
WEDNESDAY...WITH SCATTERED VFR DIURNAL CUMULUS POSSIBLE DURING THE
AFTERNOON.
BRISK NORTHWEST WINDS WILL CONTINUE THROUGH THE AFTERNOON...WITH
GUSTS UP TO 27 KNOTS. NORTHWEST WINDS WILL BE IN THE 10 TO 12 KNOT
RANGE THROUGH TONIGHT...THEN VEER NORTH WEDNESDAY AND WEAKEN.
WINDS WILL VEER NORTHEAST TO EAST AT THE EASTERN SITES WEDNESDAY
AFTERNOON AND WEAKEN AS WELL.
&&
.MARINE...SMALL CRAFT ADVISORY FOR BRISK NORTHWEST WINDS AND HIGH
WAVES TOWARD THE OPEN WATERS WILL CONTINUE UNTIL 02Z WEDNESDAY.
TIGHT PRESSURE GRADIENT AND GOOD MIXING OF LOW LEVEL WINDS SHOULD
SUPPORT GUSTS TO 30 KNOTS MIXING DOWN TO THE SURFACE DURING
DAY...WITH THE GUSTS SUBSIDING WITH NIGHTFALL. 3 TO 5 FOOT WAVES
LINGER TOWARD THE OPEN WATERS INTO THE EARLY EVENING...BEFORE
SUBSIDING TO 2 TO 4 FEET LATER THIS EVENING AND OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 331 AM CDT TUE APR 10 2012/
VERY SHORT TERM....TODAY AND TONIGHT. FORECAST CONFIDENCE...LOW
TO MEDIUM.
MOISTURE ACCOMPANYING WEAK FORCING FROM MID LEVEL SHORT WAVE OVER
NORTHWEST WISCONSIN CAUSED MID CLOUDS TO EXPAND OVER SOUTHEAST WI
OVERNIGHT. LATEST RUC CARRIES THIS WEAK WAVE ACROSS SRN WI EARLY
THIS MORNING. WATER VAPOR IMAGERY SHOWS SECOND WEAK WAVE OVER FAR
NORTH CENTRAL MN WHICH MOVES ON A SIMILAR TRACK ACROSS CENTRAL AND
SRN WI LATER THIS MRNG AND AFTN. WATER VAPOR IMAGERY AND 11-3.9
MICRON IMAGERY SHOWING MID-LEVEL MOISTURE AND CLOUDS ACCOMPANYING
BOTH OF THESE WAVES. WITH INCREASING CYCLONIC CURVATURE IN THE LOW
TO MID LEVELS...AND LINGERING THERMAL TROF...EXPECTING MORE CLOUDS
THAN SUN OVER ERN CWA...WITH MORE OF A BALANCE IN THE WEST. FOR NOW
WL HOLD OFF ON M/CLDY WORDING AS EXPECTING SEVERAL PERIODS OF AT
LEAST P/SUNNY CONDITIONS TODAY.
WL DROP DODGE AND JEFFERSON COUNTIES FROM FREEZE WARNING EARLY THIS
MRNG AS BKN-OVC SHOULD LINGER IN THESE AREAS PREVENTING TEMPS FROM
DROPPING INTO THE UPPER 20S. WITH KBUU AND KJVL IN THE LOW 30S...WL
CONTINUE FREEZE WARNING IN WALWORTH COUNTY AND POINTS WEST UNTIL
14Z. CLOUDS AND BREEZY NORTHWEST WINDS WL ONLY ALLOW DAYTIME TEMPS
TO RISE INTO THE MID TO UPPER 40S TODAY.
INCREASING SUBSIDENCE FROM PASSING LEFT ENTRANCE REGION OF UPPER JET
SHOULD HELP TO BREAK UP THE CLOUDS OVER SOUTH CENTRAL WI BUT SCT-BKN
CLOUDS MAY HANG ON IN THE EAST AS ANOTHER WEAK WAVE ROTATES AROUND
UPPER LOW OVER ONTARIO CANADA. ALSO...LOW LEVEL FLOW TURNS TO THE
NORTH TO NORTHEAST OVER THE LAKESHORE AREAS WITH THE DELTA-T AROUND
12C. HENCE WITH CLEARING IN THE WEST AND SLIGHTLY LIGHTER
WINDS...TEMPS LIKELY TO FALL BACK INTO THE UPPER 20S TO LOW 30S. DUE
TO UNCERTAINTY REGARDING CLOUDS AND TEMPS FALLING TO 28F OR LOWER
LATER TONIGHT...HELD OFF ON ISSUING ANOTHER FREEZE WARNING FOR LATE
TONIGHT AWAY FROM THE LAKE. ALSO...REMOVED FROST WORDING TONIGHT DUE
TO TEMP/DEWPOINT DEPRESSIONS REMAINING HIGH.
SHORT TERM...WEDNESDAY THROUGH THURSDAY NIGHT.
WEDNESDAY AND WEDNESDAY NIGHT...FORECAST CONFIDENCE HIGH.
TEMPERATURES REMAIN THE FOCUS AS CURRENT RELATIVELY COLD TREND
CONTINUES WITH WESTERN GREAT LAKES IN NORTHERLY FLOW BETWEEN EASTERN
TROUGH AND PLAINS RIDGE. WINDS TURN MORE NORTHERLY FOR
WEDNESDAY...BUT 925MB TEMPERATURES MODIFY A BIT UPWARD WITH DRY
ADIABATIC MIXING TO THAT LEVEL BRINGING HIGHS BACK INTO THE LOWER TO
MIDDLE 50S INLAND...WITH NORTH-NORTHEAST WINDS AND POTENTIAL FOR
LAKE STRATOCUMULUS HOLDING READINGS IN THE 40S.
WEAK...SHEARED VORTICITY ON PERIPHERY OF CYCLONIC FLOW SOUTH AND
WEST OF STATE SHIFTS BACK EAST ACROSS STATE OVERNIGHT WEDNESDAY.
ECMWF AN OUTLIER...BRINGING A STRONG VORT SOUTHEAST FROM NWRN
MN...REACHING SW WI/NW IL AROUND 06Z THURSDAY. HOWEVER COLUMN
REMAINS DRY ON ECMWF FORECAST SOUNDINGS SO NO POP...AND LITTLE TO NO
CLOUDS. LIGHT WINDS AND CLEAR SKIES WILL BRING SUB-FREEZING LOW
TEMPERATURES TO ALL BUT THE IMMEDIATE LAKESHORE AREAS. WILL HAVE
PATCHY FROST...AND AREAS OF FROST WHERE LOW TEMPS FALL BELOW 30F.
THURSDAY THROUGH THURSDAY NIGHT...FORECAST CONFIDENCE
TEMPERATURES CONTINUE TO WARM THURSDAY AS 850-700 MB RIDGE AXES
SHIFT EAST. SURFACE HIGH ALSO CENTERED OVER THE EASTERN LAKES BY 00Z
FRIDAY...WITH SOUTH WINDS BY THE AFTERNOON WEST AND SOUTHEAST WINDS
ALL DAY IN THE EAST. BLENDED SOLUTION BRINGS UPPER 50S TO LOWER 60S
WEST...WITH LOW TO MID 50S EAST.
NAM AND GFS BRING PRECIPITATION INTO THE WEST BETWEEN 06Z AND
12Z FRIDAY WITH 850-700MB WARM AIR ADVECTION/MOISTURE TRANSPORT.
WILL TIME PRECIPITATION ACROSS CWA WITH BEST ISENTROPIC ADIABATIC
OMEGA AND LOWER CONDENSATION PRESSURE DEFICITS. LOWS BETWEEN 06Z AND
09Z FRIDAY...THEN STEADY OR SLOWLY WARM WITH WARM ADVECTION AND
INCREASING CLOUDS.
LONG TERM...FRIDAY THROUGH MONDAY. FORECAST CONFIDENCE MEDIUM.
A WET END OF THE WEEK/BEGINNING OF THE WEEK AS SERIES OF SHORT WAVE
TROUGHS EJECT FROM WESTERN TROUGH. SOME PLACEMENT/TIMING DIFFERENCES
WHICH MAY IMPACT TEMPERATURES AND STORM MODE...BUT CONSENSUS BLEND
BRINGS SHOWERS AND A SLIGHT CHANCE OF THUNDERSTORMS WITH WAA
FRIDAY/FRIDAY NIGHT...THEN A CHANCE OF THUNDERSTORMS SATURDAY...
BECOMING LIKELY SATURDAY NIGHT WITH ADDITIONAL FORCING WITH SHORT
WAVE...TAPERING OFF TO SHOWERS WITH BAROCLINIC ZONE AND COOLER AIR
DROPPING SOUTH BEHIND WAVE SUNDAY NIGHT AND MONDAY. MAINLY DRY
MONDAY NIGHT...BUT SECONDARY WAVE ALONG BAROCLINIC ZONE MAY BRUSH
THE SOUTHEAST TUESDAY/TUESDAY NIGHT.
AVIATION/12Z TAFS/...PERIODS OF MOSTLY VFR CLOUDS EXPCD TODAY AND
MOSTLY ERN AREAS TONIGHT. SCT CLOUDS MAY APPROACH 3K FEET FOR A
TIME TODAY AND IN THE EAST TNGT AS THE LOW LEVEL FLOW BECOMES MORE
NLY. ANOTHER GUSTY DAY ANTICIPATED...BUT SHOULD NOT BE AS STRONG AS LAST
SEVERAL DAYS. OCCASIONAL GUSTS TO AROUND 25KTS LATER THIS MRNG AND
AFTN.
MARINE...COLD AIR WILL REMAIN ANCHORED OVER LAKE MICHIGAN FOR THE
NEXT 24 HOURS. MODIS IMAGERY FROM 17Z/09 MEASURED LAKE SURFACE
TEMPS 4-5C AWAY FROM THE SHALLOWER NEARSHORE WATERS...CONFIRMED BY
SOUTH LAKE BUOY TEMP. RESULTANT UNSTABLE CONDITIONS OVER THE LAKE
AS WELL AS OVER THE LAKESHORE AREAS...WILL ALLOW GUSTY WINDS TO
AFFECT THE NEAR SHORE WATERS. OCCASIONAL GUSTS TO 25 KTS ARE
EXPECTED LATER THIS MRNG AND AFTN...LINGERING INTO THE EARLY EVE.
WL EXTEND ONGOING SMALL CRAFT ADVY SEVERAL HOURS INTO THE EVE TO
ALLOW FOR DIMINISHING GUSTINESS. WINDS WL REMAIN GUSTY TNGT...BUT
SHOULD SUBSIDE BELOW ADVY CRITERIA.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
UPDATE...WOOD
TODAY/TONIGHT AND AVIATION/MARINE...MBK
WEDNESDAY THROUGH MONDAY...REM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
627 AM CDT TUE APR 10 2012
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
351 AM CDT TUE APR 10 2012
AT 3 AM...CURRENTLY WATCHING THE CLOUDS ACROSS NORTHERN
MINNESOTA...AND NORTHERN AND EASTERN WISCONSIN. OVERALL THE
NAM/WRF AND RUC ARE HANDLING THESE CLOUDS THE BEST...AND THEY ARE
IN GOOD AGREEMENT THAT THESE CLOUDS WILL DRIFT EAST OF THE AREA BY
THE AFTERNOON. THIS IS IN RESPONSE TO THE SURFACE HIGH BUILDING
PUSHING EAST INTO THE FORECAST AREA.
WITH 850 MB TEMPERATURES ABOUT 4C COLDER /AROUND -8C/...HIGH
TEMPERATURES THIS AFTERNOON WILL ONLY CLIMB INTO THE 40S. THIS IS
VERY GOOD AGREEMENT WITH THE CONSALL DATA SET AND ABOUT 5 DEGREE
COOLER THAN THE MOS TEMPERATURES.
FOR TONIGHT...IT LOOKS WE WILL HAVE IDEAL RADIATIVE CONDITIONS
/CLEAR SKIES...LOW DEW POINTS...AND LIGHT WINDS/ FOR TEMPERATURES
TO FALL INTO THE 20S. THERE MAY BE EVEN A FEW TEENS IN THE
CRANBERRY BOGS OF CENTRAL WISCONSIN. AS A RESULT...WE WILL HAVE TO
ISSUE ANOTHER A FREEZE WARNING. TO AVOID ANY CONFUSION...WE PLAN
ON ISSUING THE NEW WARNING AT THE SAME TIME THAT THE OTHER ONE
WILL BE EXPIRING.
ON THURSDAY...THE 10.00Z MODELS ARE MUCH SLOWER AT MOVING THE
UPPER LEVEL RIDGE EAST OF THE AREA. AS A RESULT...THE BEST 925 AND
850 MB MOISTURE TRANSPORT REMAINS WEST OF THE FORECAST AREA. IN
ADDITION...MODEL SOUNDINGS SHOW THAT THERE WILL BE QUITE A BIT OF
DRY AIR ACROSS THE REGION. DUE TO THIS...TOOK OUT THE
PRECIPITATION CHANCES THAT WERE IN THERE FORECAST GRIDS DURING THE
AFTERNOON.
ON THURSDAY NIGHT...THE MODELS ARE CONTINUING TO STRUGGLE ON THE
EASTWARD PROGRESSION OF THE UPPER LEVEL RIDGE THROUGH THE REGION.
AS A RESULT...THERE CONTINUES TO BE TIMING DIFFERENCES OF WHEN THE
PRECIPITATION WILL MOVE INTO THE AREA. THE GFS IS THE FASTEST AND
HAS THE RAIN MOVING INTO THE AREA DURING THE EVENING. BOTH THE GEM
AND NAM/WRF MOVE THE PRECIPITATION INTO THE AREA AFTER MIDNIGHT.
FINALLY...THE ECMWF CONTINUES TO KEEP THE ENTIRE AREA DRY. SINCE
THERE IS STILL A LOT OF UNCERTAINTY...KEPT THE PRECIPITATION
CHANCES MAINLY IN THE 30 TO 50 PERCENT RANGE.
.LONG TERM...FRIDAY THROUGH MONDAY
351 AM CDT TUE APR 10 2012
LIKE THEIR PREDECESSORS...THE 10.00Z MODELS CONTINUE TO SHOW VERY
LITTLE RUN TO RUN CONSISTENCY...SO FORECAST CONFIDENCE IS MUCH
LOWER THAN USUAL.
OVERALL...THE MODELS ARE STILL IN GENERAL AGREEMENT THAT THE
UPPER LEVEL RIDGE WILL MOVE RAPIDLY EAST ACROSS THE AREA BY FRIDAY...
BUT THIS OCCURS A BIT SLOWER THAN WHAT WAS INDICATED EARLIER IN
THE WEEK. AS THIS RIDGE MOVES EAST...A SERIES OF SHORT WAVES EJECT
OUT OF THE WESTERN LONG WAVE TROUGH. THE TIMING OF THESE SYSTEMS
HAVE BEEN SO INCONSISTENT THAT THE PRECIPITATION WAS BROAD
BRUSHED. HOWEVER THIS SET OF MODELS INDICATE THAT THE HIGHER RAIN
CHANCES LOOK TO BE ON FRIDAY NIGHT AND SATURDAY NIGHT. WITH MOST
UNSTABLE CAPES OF 500 TO 1000 J/KG...THERE WILL ENOUGH INSTABILITY
FOR THE DEVELOPMENT OF SOME THUNDERSTORMS TO GO ALONG WITH THE
SHOWERS.
AS WE HEAD INTO EARLY NEXT WEEK...THE MODELS QUICKLY DEVELOP A
SPLIT FLOW. THE SOUTHERN STREAM KEEPS A TROUGH FROM THE CENTRAL
PLAINS INTO THE SOUTHWEST UNITED STATES. MEANWHILE THE NORTHERN
STREAM SYSTEM DIPS DOWN INTO THE NORTHERN GREAT LAKES. THIS WOULD
POTENTIALLY ALLOW ANOTHER COOL CANADIAN HIGH TO MOVE SOUTHWARD
INTO THE UPPER MISSISSIPPI RIVER VALLEY. IT IS THIS TIME PERIOD
WHERE THE CONFIDENCE IS EXTREMELY LOW. MUCH OF THIS HAS TO DEAL
WITH HOW THE MODELS ARE NOT HANDLING A MODERATE TO STRONG MADDEN
JULIAN OSCILLATION /CURRENTLY LOCATED OVER SOUTH AMERICA AND
ATLANTIC/. WITH THE EXCEPTION OF THE JAPANESE METEOROLOGY AGENCY
ENSEMBLE SYSTEM /JMAN/...MOST OF THE GLOBAL MODELS WIPE OUT THIS
MJO RAPIDLY BY EARLY NEXT WEEK. HOWEVER CONSIDERING ITS
STRENGTH...THIS SEEMS RATHER UNLIKELY. AS A RESULT...EXPECT A
BRIEF WARM UP AS WE ENTER PHASE 1 /OVER AFRICA/ BY THIS
WEEKEND...FOLLOWED BY YET ANOTHER COOL DOWN AS THE MJO STARTS INTO
THE WESTERN INDIAN OCEAN /PHASE 2/ BY THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...TODAY AND TONIGHT
627 AM CDT TUE APR 10 2012
A WEAK CYCLONIC FLOW IS STILL IN PLACE OVER THE GREAT LAKES AND
SOME MOISTURE TRAPPED IN THIS FLOW IS RESULTING IN A LAYER OF VFR
CLOUDS ACROSS NORTHERN WISCONSIN INTO EASTERN MINNESOTA. SOME OF
THESE CLOUDS HAVE PRODUCED A CEILING AT BOTH KRGK AND KMSP AND
COULD POSSIBLY ROTATE INTO KLSE BY MID MORNING. HOWEVER...IR
SATELLITE IS SHOWING A SLOW DIMINISHING TREND SO THE CLOUDS COULD
BE NOTHING MORE THAN A SCATTERED DECK BY THE TIME THEY ARRIVE AT
KLSE. DECIDED TO CARRY THE SCATTERED CLOUDS WITH A TEMPO FOR A
BROKEN CEILING FOR A COUPLE OF HOURS DURING THE MID AND LATE
MORNING. ONCE THE INVERSION BREAKS THIS MORNING...BUFKIT FORECAST
SOUNDINGS SHOW ANOTHER DAY WITH DEEP MIXING AT BOTH SITES. THIS
WILL PRODUCE A THIRD STRAIGHT DAY WITH GUSTY NORTHWEST WINDS...BUT
THE WINDS ARE NOT EXPECTED TO BE QUITE AS STRONG AS THE PREVIOUS
TWO DAYS. EXPECTING SUSTAINED SPEEDS TO BE BETWEEN 15 AND 20 KNOTS
WITH GUSTS INTO THE MID 20 KNOT RANGE. THE WINDS WILL DIMINISH
THIS EVENING WITH SUNSET AND AS THE SURFACE RIDGE AXIS GETS CLOSER
TO THE REGION.
&&
.FIRE WEATHER...THROUGH WEDNESDAY
351 AM CDT TUE APR 10 2012
TEMPERATURES WILL BE ANOTHER 5 TO 10 DEGREES COLDER THAN THEY WERE
ON MONDAY AFTERNOON. MEANWHILE THE DEW POINTS WILL BE SIMILAR. AS
A RESULT...THE RELATIVE HUMIDITIES /25 TO 30 PERCENT/ WILL BE A
BIT HIGHER THIS AFTERNOON. THE SUSTAINED WIND SPEEDS WILL BE
SLIGHTLY LOWER /AROUND 20 MPH/ THAN THEY WERE ON MONDAY AFTERNOON
TOO. ALL OF THESE ALONG WITH VERY HIGH TO EXTREME FIRE WEATHER
CONDITIONS WILL LEAD TO ANOTHER CRITICAL FIRE WEATHER DAY /JUST
UNDER RED FLAG WARNING CRITERIA/ FOR TODAY. ANY PLANS FOR OUTDOOR
BURNING SHOULD BE AVOIDED.
ON WEDNESDAY...WE DO NOT MIX QUITE AS DEEP /UP TO 875 MB/ AND THE
DEW POINTS WILL BE SLIGHTLY HIGHER...SO RELATIVE HUMIDITIES WILL
BE CLOSER TO 30 PERCENT. IN ADDITION...THERE WILL BE MUCH LIGHTER
WINDS AS THE HIGH PRESSURE SYSTEM DRIFTS OVERHEAD. WITH LESS WIND
AND SLIGHTLY HIGHER RELATIVE HUMIDITIES...NOT EXPECTING THE RAPID
SPREAD OF ANY FIRES THAT HAPPEN TO DEVELOP.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
259 AM CDT TUE APR 10 2012
WI...FREEZE WARNING UNTIL 10 AM CDT THIS MORNING FOR WIZ017-029-
032>034-041>044-053>055-061.
MN...FREEZE WARNING UNTIL 10 AM CDT THIS MORNING FOR MNZ079-086>088-
094>096.
IA...FREEZE WARNING UNTIL 10 AM CDT THIS MORNING FOR IAZ008>011-018-
019-029-030.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...04
FIRE WEATHER......BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
352 AM CDT TUE APR 10 2012
.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
351 AM CDT TUE APR 10 2012
AT 3 AM...CURRENTLY WATCHING THE CLOUDS ACROSS NORTHERN
MINNESOTA...AND NORTHERN AND EASTERN WISCONSIN. OVERALL THE
NAM/WRF AND RUC ARE HANDLING THESE CLOUDS THE BEST...AND THEY ARE
IN GOOD AGREEMENT THAT THESE CLOUDS WILL DRIFT EAST OF THE AREA BY
THE AFTERNOON. THIS IS IN RESPONSE TO THE SURFACE HIGH BUILDING
PUSHING EAST INTO THE FORECAST AREA.
WITH 850 MB TEMPERATURES ABOUT 4C COLDER /AROUND -8C/...HIGH
TEMPERATURES THIS AFTERNOON WILL ONLY CLIMB INTO THE 40S. THIS IS
VERY GOOD AGREEMENT WITH THE CONSALL DATA SET AND ABOUT 5 DEGREE
COOLER THAN THE MOS TEMPERATURES.
FOR TONIGHT...IT LOOKS WE WILL HAVE IDEAL RADIATIVE CONDITIONS
/CLEAR SKIES...LOW DEW POINTS...AND LIGHT WINDS/ FOR TEMPERATURES
TO FALL INTO THE 20S. THERE MAY BE EVEN A FEW TEENS IN THE
CRANBERRY BOGS OF CENTRAL WISCONSIN. AS A RESULT...WE WILL HAVE TO
ISSUE ANOTHER A FREEZE WARNING. TO AVOID ANY CONFUSION...WE PLAN
ON ISSUING THE NEW WARNING AT THE SAME TIME THAT THE OTHER ONE
WILL BE EXPIRING.
ON THURSDAY...THE 10.00Z MODELS ARE MUCH SLOWER AT MOVING THE
UPPER LEVEL RIDGE EAST OF THE AREA. AS A RESULT...THE BEST 925 AND
850 MB MOISTURE TRANSPORT REMAINS WEST OF THE FORECAST AREA. IN
ADDITION...MODEL SOUNDINGS SHOW THAT THERE WILL BE QUITE A BIT OF
DRY AIR ACROSS THE REGION. DUE TO THIS...TOOK OUT THE
PRECIPITATION CHANCES THAT WERE IN THERE FORECAST GRIDS DURING THE
AFTERNOON.
ON THURSDAY NIGHT...THE MODELS ARE CONTINUING TO STRUGGLE ON THE
EASTWARD PROGRESSION OF THE UPPER LEVEL RIDGE THROUGH THE REGION.
AS A RESULT...THERE CONTINUES TO BE TIMING DIFFERENCES OF WHEN THE
PRECIPITATION WILL MOVE INTO THE AREA. THE GFS IS THE FASTEST AND
HAS THE RAIN MOVING INTO THE AREA DURING THE EVENING. BOTH THE GEM
AND NAM/WRF MOVE THE PRECIPITATION INTO THE AREA AFTER MIDNIGHT.
FINALLY...THE ECMWF CONTINUES TO KEEP THE ENTIRE AREA DRY. SINCE
THERE IS STILL A LOT OF UNCERTAINTY...KEPT THE PRECIPITATION
CHANCES MAINLY IN THE 30 TO 50 PERCENT RANGE.
.LONG TERM...FRIDAY THROUGH MONDAY
351 AM CDT TUE APR 10 2012
LIKE THEIR PREDECESSORS...THE 10.00Z MODELS CONTINUE TO SHOW VERY
LITTLE RUN TO RUN CONSISTENCY...SO FORECAST CONFIDENCE IS MUCH
LOWER THAN USUAL.
OVERALL...THE MODELS ARE STILL IN GENERAL AGREEMENT THAT THE
UPPER LEVEL RIDGE WILL MOVE RAPIDLY EAST ACROSS THE AREA BY FRIDAY...
BUT THIS OCCURS A BIT SLOWER THAN WHAT WAS INDICATED EARLIER IN
THE WEEK. AS THIS RIDGE MOVES EAST...A SERIES OF SHORT WAVES EJECT
OUT OF THE WESTERN LONG WAVE TROUGH. THE TIMING OF THESE SYSTEMS
HAVE BEEN SO INCONSISTENT THAT THE PRECIPITATION WAS BROAD
BRUSHED. HOWEVER THIS SET OF MODELS INDICATE THAT THE HIGHER RAIN
CHANCES LOOK TO BE ON FRIDAY NIGHT AND SATURDAY NIGHT. WITH MOST
UNSTABLE CAPES OF 500 TO 1000 J/KG...THERE WILL ENOUGH INSTABILITY
FOR THE DEVELOPMENT OF SOME THUNDERSTORMS TO GO ALONG WITH THE
SHOWERS.
AS WE HEAD INTO EARLY NEXT WEEK...THE MODELS QUICKLY DEVELOP A
SPLIT FLOW. THE SOUTHERN STREAM KEEPS A TROUGH FROM THE CENTRAL
PLAINS INTO THE SOUTHWEST UNITED STATES. MEANWHILE THE NORTHERN
STREAM SYSTEM DIPS DOWN INTO THE NORTHERN GREAT LAKES. THIS WOULD
POTENTIALLY ALLOW ANOTHER COOL CANADIAN HIGH TO MOVE SOUTHWARD
INTO THE UPPER MISSISSIPPI RIVER VALLEY. IT IS THIS TIME PERIOD
WHERE THE CONFIDENCE IS EXTREMELY LOW. MUCH OF THIS HAS TO DEAL
WITH HOW THE MODELS ARE NOT HANDLING A MODERATE TO STRONG MADDEN
JULIAN OSCILLATION /CURRENTLY LOCATED OVER SOUTH AMERICA AND
ATLANTIC/. WITH THE EXCEPTION OF THE JAPANESE METEOROLOGY AGENCY
ENSEMBLE SYSTEM /JMAN/...MOST OF THE GLOBAL MODELS WIPE OUT THIS
MJO RAPIDLY BY EARLY NEXT WEEK. HOWEVER CONSIDERING ITS
STRENGTH...THIS SEEMS RATHER UNLIKELY. AS A RESULT...EXPECT A
BRIEF WARM UP AS WE ENTER PHASE 1 /OVER AFRICA/ BY THIS
WEEKEND...FOLLOWED BY YET ANOTHER COOL DOWN AS THE MJO STARTS INTO
THE WESTERN INDIAN OCEAN /PHASE 2/ BY THE MIDDLE OF NEXT WEEK.
&&
.AVIATION...
1105 PM CDT MON APR 9 2012
A DECENT PRESSURE GRADIENT PERSISTS ON TUESDAY...WITH BUFKIT
SOUNDINGS POINTING TO MIXING OF UNIDIRECTIONAL WINDS UPWARDS OF 850
MB. NORTHWEST WINDS WILL RAMP BACK UP BETWEEN 13-15Z TUE...WITH
GUSTS NEARING 30 MPH AT KRST. IT DOESN/T APPEAR AS WINDY AS TODAY
THOUGH. WINDS WILL HAVE THE USUAL DIURNAL DIP WITH SUNDOWN.
BKN-OVC 5 KFT CLOUDS CONTINUE TO HANG OVER NORTHERN PARTS OF MN/WI
LATEST RUC13/NAM12 SUGGEST THAT THESE CLOUDS SHOULD STAY
NORTH/NORTHEAST OF KRST/KLSE...ALTHOUGH SEE SOME THREAT OF GETTING
INTO KLSE. SOME AFTERNOON CU ON THE SOUTHERN EDGE OF THE CLOUD MASS
SEEMS MORE LIKELY.
&&
.FIRE WEATHER...THROUGH WEDNESDAY
351 AM CDT TUE APR 10 2012
TEMPERATURES WILL BE ANOTHER 5 TO 10 DEGREES COLDER THAN THEY WERE
ON MONDAY AFTERNOON. MEANWHILE THE DEW POINTS WILL BE SIMILAR. AS
A RESULT...THE RELATIVE HUMIDITIES /25 TO 30 PERCENT/ WILL BE A
BIT HIGHER THIS AFTERNOON. THE SUSTAINED WIND SPEEDS WILL BE
SLIGHTLY LOWER /AROUND 20 MPH/ THAN THEY WERE ON MONDAY AFTERNOON
TOO. ALL OF THESE ALONG WITH VERY HIGH TO EXTREME FIRE WEATHER
CONDITIONS WILL LEAD TO ANOTHER CRITICAL FIRE WEATHER DAY /JUST
UNDER RED FLAG WARNING CRITERIA/ FOR TODAY. ANY PLANS FOR OUTDOOR
BURNING SHOULD BE AVOIDED.
ON WEDNESDAY...WE DO NOT MIX QUITE AS DEEP /UP TO 875 MB/ AND THE
DEW POINTS WILL BE SLIGHTLY HIGHER...SO RELATIVE HUMIDITIES WILL
BE CLOSER TO 30 PERCENT. IN ADDITION...THERE WILL BE MUCH LIGHTER
WINDS AS THE HIGH PRESSURE SYSTEM DRIFTS OVERHEAD. WITH LESS WIND
AND SLIGHTLY HIGHER RELATIVE HUMIDITIES...NOT EXPECTING THE RAPID
SPREAD OF ANY FIRES THAT HAPPEN TO DEVELOP.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
259 AM CDT TUE APR 10 2012
WI...FREEZE WARNING UNTIL 10 AM CDT THIS MORNING FOR WIZ017-029-
032>034-041>044-053>055-061.
MN...FREEZE WARNING UNTIL 10 AM CDT THIS MORNING FOR MNZ079-086>088-
094>096.
IA...FREEZE WARNING UNTIL 10 AM CDT THIS MORNING FOR IAZ008>011-018-
019-029-030.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION..........RIECK
FIRE WEATHER......BOYNE
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
331 AM CDT TUE APR 10 2012
.VERY SHORT TERM....TODAY AND TONIGHT. FORECAST CONFIDENCE...LOW
TO MEDIUM.
MOISTURE ACCOMPANYING WEAK FORCING FROM MID LEVEL SHORT WAVE OVER
NORTHWEST WISCONSIN CAUSED MID CLOUDS TO EXPAND OVER SOUTHEAST WI
OVERNIGHT. LATEST RUC CARRIES THIS WEAK WAVE ACROSS SRN WI EARLY
THIS MORNING. WATER VAPOR IMAGERY SHOWS SECOND WEAK WAVE OVER FAR
NORTH CENTRAL MN WHICH MOVES ON A SIMILAR TRACK ACROSS CENTRAL AND
SRN WI LATER THIS MRNG AND AFTN. WATER VAPOR IMAGERY AND 11-3.9
MICRON IMAGERY SHOWING MID-LEVEL MOISTURE AND CLOUDS ACCOMPANYING
BOTH OF THESE WAVES. WITH INCREASING CYCLONIC CURVATURE IN THE LOW
TO MID LEVELS...AND LINGERING THERMAL TROF...EXPECTING MORE CLOUDS
THAN SUN OVER ERN CWA...WITH MORE OF A BALANCE IN THE WEST. FOR NOW
WL HOLD OFF ON M/CLDY WORDING AS EXPECTING SEVERAL PERIODS OF AT
LEAST P/SUNNY CONDITIONS TODAY.
WL DROP DODGE AND JEFFERSON COUNTIES FROM FREEZE WARNING EARLY THIS
MRNG AS BKN-OVC SHOULD LINGER IN THESE AREAS PREVENTING TEMPS FROM
DROPPING INTO THE UPPER 20S. WITH KBUU AND KJVL IN THE LOW 30S...WL
CONTINUE FREEZE WARNING IN WALWORTH COUNTY AND POINTS WEST UNTIL
14Z. CLOUDS AND BREEZY NORTHWEST WINDS WL ONLY ALLOW DAYTIME TEMPS
TO RISE INTO THE MID TO UPPER 40S TODAY.
INCREASING SUBSIDENCE FROM PASSING LEFT ENTRANCE REGION OF UPPER JET
SHOULD HELP TO BREAK UP THE CLOUDS OVER SOUTH CENTRAL WI BUT SCT-BKN
CLOUDS MAY HANG ON IN THE EAST AS ANOTHER WEAK WAVE ROTATES AROUND
UPPER LOW OVER ONTARIO CANADA. ALSO...LOW LEVEL FLOW TURNS TO THE
NORTH TO NORTHEAST OVER THE LAKESHORE AREAS WITH THE DELTA-T AROUND
12C. HENCE WITH CLEARING IN THE WEST AND SLIGHTLY LIGHTER
WINDS...TEMPS LIKELY TO FALL BACK INTO THE UPPER 20S TO LOW 30S. DUE
TO UNCERTAINTY REGARDING CLOUDS AND TEMPS FALLING TO 28F OR LOWER
LATER TONIGHT...HELD OFF ON ISSUING ANOTHER FREEZE WARNING FOR LATE
TONIGHT AWAY FROM THE LAKE. ALSO...REMOVED FROST WORDING TONIGHT DUE
TO TEMP/DEWPOINT DEPRESSIONS REMAINING HIGH.
.SHORT TERM...WEDNESDAY THROUGH THURSDAY NIGHT.
WEDNESDAY AND WEDNESDAY NIGHT...FORECAST CONFIDENCE HIGH.
TEMPERATURES REMAIN THE FOCUS AS CURRENT RELATIVELY COLD TREND
CONTINUES WITH WESTERN GREAT LAKES IN NORTHERLY FLOW BETWEEN EASTERN
TROUGH AND PLAINS RIDGE. WINDS TURN MORE NORTHERLY FOR
WEDNESDAY...BUT 925MB TEMPERATURES MODIFY A BIT UPWARD WITH DRY
ADIABATIC MIXING TO THAT LEVEL BRINGING HIGHS BACK INTO THE LOWER TO
MIDDLE 50S INLAND...WITH NORTH-NORTHEAST WINDS AND POTENTIAL FOR
LAKE STRATOCUMULUS HOLDING READINGS IN THE 40S.
WEAK...SHEARED VORTICITY ON PERIPHERY OF CYCLONIC FLOW SOUTH AND
WEST OF STATE SHIFTS BACK EAST ACROSS STATE OVERNIGHT WEDNESDAY.
ECMWF AN OUTLIER...BRINGING A STRONG VORT SOUTHEAST FROM NWRN
MN...REACHING SW WI/NW IL AROUND 06Z THURSDAY. HOWEVER COLUMN
REMAINS DRY ON ECMWF FORECAST SOUNDINGS SO NO POP...AND LITTLE TO NO
CLOUDS. LIGHT WINDS AND CLEAR SKIES WILL BRING SUB-FREEZING LOW
TEMPERATURES TO ALL BUT THE IMMEDIATE LAKESHORE AREAS. WILL HAVE
PATCHY FROST...AND AREAS OF FROST WHERE LOW TEMPS FALL BELOW 30F.
THURSDAY THROUGH THURSDAY NIGHT...FORECAST CONFIDENCE
TEMPERATURES CONTINUE TO WARM THURSDAY AS 850-700 MB RIDGE AXES
SHIFT EAST. SURFACE HIGH ALSO CENTERED OVER THE EASTERN LAKES BY 00Z
FRIDAY...WITH SOUTH WINDS BY THE AFTERNOON WEST AND SOUTHEAST WINDS
ALL DAY IN THE EAST. BLENDED SOLUTION BRINGS UPPER 50S TO LOWER 60S
WEST...WITH LOW TO MID 50S EAST.
NAM AND GFS BRING PRECIPITATION INTO THE WEST BETWEEN 06Z AND
12Z FRIDAY WITH 850-700MB WARM AIR ADVECTION/MOISTURE TRANSPORT.
WILL TIME PRECIPITATION ACROSS CWA WITH BEST ISENTROPIC ADIABATIC
OMEGA AND LOWER CONDENSATION PRESSURE DEFICITS. LOWS BETWEEN 06Z AND
09Z FRIDAY...THEN STEADY OR SLOWLY WARM WITH WARM ADVECTION AND
INCREASING CLOUDS.
.LONG TERM...FRIDAY THROUGH MONDAY. FORECAST CONFIDENCE MEDIUM.
A WET END OF THE WEEK/BEGINNING OF THE WEEK AS SERIES OF SHORT WAVE
TROUGHS EJECT FROM WESTERN TROUGH. SOME PLACEMENT/TIMING DIFFERENCES
WHICH MAY IMPACT TEMPERATURES AND STORM MODE...BUT CONSENSUS BLEND
BRINGS SHOWERS AND A SLIGHT CHANCE OF THUNDERSTORMS WITH WAA
FRIDAY/FRIDAY NIGHT...THEN A CHANCE OF THUNDERSTORMS SATURDAY...
BECOMING LIKELY SATURDAY NIGHT WITH ADDITIONAL FORCING WITH SHORT
WAVE...TAPERING OFF TO SHOWERS WITH BAROCLINIC ZONE AND COOLER AIR
DROPPING SOUTH BEHIND WAVE SUNDAY NIGHT AND MONDAY. MAINLY DRY
MONDAY NIGHT...BUT SECONDARY WAVE ALONG BAROCLINIC ZONE MAY BRUSH
THE SOUTHEAST TUESDAY/TUESDAY NIGHT.
&&
.AVIATION/12Z TAFS/...PERIODS OF MOSTLY VFR CLOUDS EXPCD TODAY AND
MOSTLY ERN AREAS TONIGHT. SCT CLOUDS MAY APPROACH 3K FEET FOR A
TIME TODAY AND IN THE EAST TNGT AS THE LOW LEVEL FLOW BECOMES MORE
NLY. ANOTHER GUSTY DAY ANTICIPATED...BUT SHOULD NOT BE AS STRONG AS LAST
SEVERAL DAYS. OCCASIONAL GUSTS TO AROUND 25KTS LATER THIS MRNG AND
AFTN.
&&
.MARINE...COLD AIR WILL REMAIN ANCHORED OVER LAKE MICHIGAN FOR THE
NEXT 24 HOURS. MODIS IMAGERY FROM 17Z/09 MEASURED LAKE SURFACE
TEMPS 4-5C AWAY FROM THE SHALLOWER NEARSHORE WATERS...CONFIRMED BY
SOUTH LAKE BUOY TEMP. RESULTANT UNSTABLE CONDITIONS OVER THE LAKE
AS WELL AS OVER THE LAKESHORE AREAS...WILL ALLOW GUSTY WINDS TO
AFFECT THE NEAR SHORE WATERS. OCCASIONAL GUSTS TO 25 KTS ARE
EXPECTED LATER THIS MRNG AND AFTN...LINGERING INTO THE EARLY EVE.
WL EXTEND ONGOING SMALL CRAFT ADVY SEVERAL HOURS INTO THE EVE TO
ALLOW FOR DIMINISHING GUSTINESS. WINDS WL REMAIN GUSTY TNGT...BUT
SHOULD SUBSIDE BELOW ADVY CRITERIA.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...FREEZE WARNING UNTIL 9 AM CDT THIS MORNING FOR WIZ046-047-056-
057-062-063-067>070.
LM...SMALL CRAFT ADVISORY UNTIL 9 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...MBK
WEDNESDAY THROUGH MONDAY...REM
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
257 AM MDT TUE APR 10 2012
.SHORT TERM...TODAY THROUGH THURSDAY EVENING
PLETHORA OF SHORT TERM FORECAST CONCERNS...DEALING MAINLY WITH
FIRE WEATHER CONCERNS THROUGH WEDNESDAY.
CURRENTLY...STALLED FRONTAL BOUNDARY OVER THE AREA LIES ACROSS
CENTRAL COLORADO...UP INTO CARBON COUNTY AND THEN NORTHWEST INTO
WESTERN WASHINGTON STATE THIS MORNING. EAST OF THIS BOUNDARY...THE
LOWER ATMOSPHERE HAS REALLY MOISTENED UP WITH LOW STRATUS
EXTENDING FROM EASTERN COLORADO UP INTO THE SOUTHERN LARAMIE RANGE
SO FAR THIS MORNING. THIS STRATUS IS JUST STARTING TO PUSH INTO
THE SOUTHERN PANHANDLE ATTM. OFF TO OUR WEST...A FAIRLY STRONG
COLD FRONT IS JUST COMING ASHORE NEAR THE NORTHERN CALIFORNIA COAST.
FOR TODAY...ONE MORE DRY DAY WITH TEMPERATURES CLIMBING BACK INTO
THE LOW 70S AT MOST LOCATIONS. AFTERNOON TEMPERATURES WILL BE
QUITE TRICKY EAST OF THE LARAMIE RANGE AND SOUTHERN
PANHANDLE...DEPENDING ON WHEN STRATUS BREAKS UP. MODEL SOUNDINGS
SHOWING FAIRLY LIGHT WINDS...THAT WILL KEEP CRITICAL FIRE WEATHER
CONDITIONS AT BAY. WE WILL BE RIGHT UNDER THE UPPER RIDGE AXIS
TODAY AS IT MOVES EAST ACROSS SOUTHEAST WYOMING AND EVENTUALLY
INTO THE PANHANDLE. BOUNDARY JUST OFF TO OUR WEST OVER IN CARBON
COUNTY SHOULD PROGRESS EASTWARD AND SERVE AS THE FOCUSING
MECHANISM FOR SOME ISOLATED THUNDERSTORMS THIS AFTERNOON AND EARLY
EVENING. NOTHING TOO MAJOR THOUGH AS AFTERNOON LIFTED INDICES ONLY
DROP TO -3 WITH CAPES OVER THE SOUTHERN LARAMIE RANGE AROUND 500
J/KG. NAM FORECAST THIS AFTERNOON DOES SHOW CAP BREAKING AROUND
21-22Z WITH CONVECTIVE INHIBITION DROPPING LESS THAN -50 J/KG.
WILL HAVE TO WATCH THIS CLOSELY...DEPENDING ON HOW EARLY THE
STRATUS BURNS OFF. LOOK FOR A RETURN OF THE STRATUS TONIGHT AS WE
STAY IN THE SOUTHEASTERLY UPSLOPING WIND FLOW. CONTINUED THE
INHERITED STRATUS AND FOG FOR LOCATIONS EAST OF THE LARAMIE RANGE
AND NEBRASKA PANHANDLE FOR LATER THIS EVENING.
UPPER RIDGE AXIS MOVES OFF TO OUR EAST WEDNESDAY MORNING WITH
STRONG WESTERLY WINDS RETURNING TO SOUTH CENTRAL WYOMING BY THE
MID MORNING HOURS. A VERY DRY AIRMASS FORECAST OUT OVER CARBON
COUNTY TOMORROW AFTERNOON AS 700MB WINDS INCREASE TO 30-35KTS.
UPPER SHORTWAVE FORECAST ON THE GFS TO BE TRACKING ACROSS UTAH BY
WEDNESDAY AFTERNOON WITH BROAD UPPER LEVEL DIVERGENCE OVER MOST OF
WYOMING. BOUNDARY CONTINUES TO LIE OVER THE PANHANDLE WITH THIS
AREA REMAINING IN STRATUS AND THUS CAPPED FOR MOST OF THE DAY. GFS
IS SHOWING CONVECTION DEVELOPING OVER THE LARAMIE RANGE WEDNESDAY
AFTERNOON WITH A DECENT WARM UP IN TEMPERATURES FOR WYOMING AREAS
EAST OF THE LARAMIE RANGE. WILL CONTINUE THE CHANCE FOR AFTERNOON
THUNDERSTORMS.
COULD SEE A FAIRLY STRONG WIND EVENT THURSDAY MORNING AS GFS SHOWS
700MB WINDS INCREASING TO 60KTS OVER CONVERSE AND NORTHERN CARBON
COUNTIES. WILL LET THE DAY SHIFT TAKE ANOTHER LOOK AT THE
POSSIBILITY OF A HIGH WIND WATCH ON THIS EVENT. FRONT MOVES
THROUGH THURSDAY EVENING WITH 700MB TEMPERATURES DROPPING DOWN TO
AROUND -6C BY FRIDAY MORNING.
.LONG TERM...FRIDAY THROUGH MONDAY
MAIN FORECAST CONCERN IN THE EXTENDED PERIOD IS THE POTENTIAL FOR
A POTENT STORM SYSTEM TO MOVE OVER THE CWA OVER THE WEEKEND.
MODELS SHOW SOUTHWESTERLY MIDLEVEL FLOW ON FRI. A WEAK SHORTWAVE
IS PROGGED TO MOVE OVER THE NEBRASKA PANHANDLE ON FRI AFTN...AND
WITH SOME 700-500MB MOISTURE CANNOT RULE OUT ISOLATED RAIN
SHOWERS. HOWEVER...THE BOUNDARY LAYER WINDS WILL BE OUT OF THE
WEST WHICH IS NOT FAVORABLE FOR PRECIP TO THE EAST OF THE LARAMIE
RANGE. ATTENTION THEN TURNS TO THE TROUGH THAT DIGS INTO THE
INTERMOUNTAIN WEST AND FOUR CORNERS ON FRI NIGHT. WHILE THE MODELS
AGREE ON AMPLIFYING THE TROUGH INTO UT/AZ ON FRI NIGHT...THEY DIFFER
ON HOW THE SYSTEM EJECTS EASTWARD. THE GFS AND ECMWF SHOW MORE OF
AN OPEN MIDLEVEL TROUGH AS THE MAIN ENERGY MOVES OVER EASTERN CO
ON SAT AFTN...WHEREAS THE CANADIAN IS MORE CLOSED. REGARDLESS OF
THE SOLN...A COLD FRONT IS PROGGED PASS OVER THE AREA ON SAT
MORNING ALONG WITH DEEPENING AND STRENGTHENING UPWARD VERTICAL
MOTION. QG UPWARD MOTION PLOTS ARE VERY IMPRESSIVE FROM LOW TO
UPPER LEVELS...ESPECIALLY OVER THE SOUTHERN PART OF THE CWA.
SOUNDINGS AT KCYS DURING THE PRECIP EVENT SUPPORT SNOW...WITH NE
UPSLOPE WINDS AND WET BULB ZERO LEVELS NEAR THE GROUND. FURTHER
EAST OVER THE LOWER ELEVATIONS OF THE NEBRASKA PANHANDLE...RAIN
WITH PERHAPS A MIXTURE OF SNOW LOOKS MOST PROBABLE. DRYING OCCURS
ON SUN AFTN AS THE MAIN ENERGY PULLS EASTWARD...WITH A WEAK TROUGH
LEFT BEHIND OVER SOUTHERN CO/NORTHERN NM. THIS SYSTEM SHOWS
INCREASING POTENTIAL TO BRING WIDESPREAD AND NEEDED PRECIP TO THE
CWA. WILL CONTINUE TO MONITOR THE EVOLUTION OF THE WEEKEND STORM.
&&
.AVIATION...06Z TAFS
MAIN ISSUE TONIGHT WILL BE THE POTENTIAL FOR PATCHY FOG AND LOW
STRATUS DEVELOPMENT OVER PARTS OF EXTREME SOUTHEAST WYOMING AND
THE SOUTHERN PANHANDLE. HRRR AND TO A LESSER EXTENT THE SREF SHOW
HIGHEST PROBABILITIES FOR MVFR OR LOWER CONDITIONS FROM CHEYENNE
TO SIDNEY. MAY SEE SOME SCATTERED STRATUS AT SCOTTSBLUFF AND
ALLIANCE AS WELL. OTHERWISE...EXPECT PARTLY CLOUDY SKIES AS
PERIODS OF CIRRUS SPREAD FROM WEST TO EAST THROUGH THE FORECAST
PERIOD. WINDS WILL BE EAST TO SOUTHEAST OVERNIGHT LESS THAN 10 KT
OVERNIGHT. ON TUESDAY...ANY FOG AND/OR LOW CLOUDS BURN SHOULD
DISSIPATE AROUND MID-MORNING...WITH VFR CONDITIONS INTO THE
AFTERNOON. THERE WILL BE A SLIGHT RISK FOR A FEW GUSTY
THUNDERSTORMS AFTER 21Z AT CHEYENNE. SOUTHERLY WINDS WILL BE
BREEZY AT TIMES WITH OCCASIONAL GUSTS OF 18 TO 25 KT.
&&
.FIRE WEATHER...
WARM AND DRY CONDITIONS CONTINUE TODAY FOR AREAS WEST OF THE LARAMIE
RANGE. FORTUNATELY...WINDS LOOK TO BE FAIRLY LIGHT TODAY KEEPING FIRE
WEATHER CONDITIONS MINIMAL TODAY. HOWEVER...AN APPROACHING COLD FRONT
WEDNESDAY MORNING WILL INCREASE SOUTHWEST WINDS BY MID MORNING
WEDNESDAY. AFTERNOON HUMIDITIES WILL BE QUITE LOW...DROPPING TO 10
PERCENT WEDNESDAY AFTERNOON. MID LEVEL MOISTURE WILL BE ON THE
INCREASE AS WELL WEDNESDAY AFTERNOON THAT COULD SET OFF WIDELY
SCATTERED DRY THUNDERSTORMS OVER CARBON AND ALBANY COUNTIES THROUGH
THE AFTERNOON. CONDITIONS MOISTEN WEDNESDAY EVENING AS THE COLD FRONT
MOVES THROUGH THE AREA...BRINGING BETTER CHANCES FOR WETTING RAINS AND
DECREASING FIRE WEATHER CONDITIONS. WIDESPREAD RAIN AND MOUNTAIN SNOWS
ARE EXPECTED THIS WEEKEND...WHICH WILL ACCELERATE THE SPRING GREEN UP
AND DECREASE FIRE WEATHER ISSUES.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...CLAYCOMB
LONG TERM/AVIATION...FINCH
AREA FORECAST DISCUSSION
NWS MIAMI FL
129 AM EDT THU APR 12 2012
.AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGHOUT THE FORECAST PERIOD. A LIGHT AND
VARIABLE FLOW WILL CONTINUE ACROSS MOST OF THE SOUTH FLORIDA
TERMINALS THROUGH THE OVERNIGHT HOURS. A WEAK COLD FRONT WILL MOVE
INTO THE REGION EARLY THURSDAY MORNING SHIFTING THE WINDS TO THE
NORTHEAST AND THEN EVENTUALLY TO THE EAST BY THURSDAY AFTERNOON AS
THE SEA BREEZE DEVELOPS. WINDS AT KAPF WILL REMAIN OUT OF THE WEST
AS A WEST COAST SEA BREEZE DEVELOPS ON THURSDAY AFTERNOON.
ISOLATED SHOWERS OR THUNDERSTORMS MAY DEVELOP NEAR THE EAST COAST
TERMINALS DURING THE AFTERNOON SO WE LEFT THE VCSH IN AFTER 18Z.
EASTERLY FLOW WILL CONTINUE THURSDAY NIGHT WITH WIND SPEEDS
RANGING BETWEEN 5 AND 10 KNOTS.
&&
.PREV DISCUSSION... /ISSUED 934 PM EDT WED APR 11 2012/
UPDATE...DRY AND TRANQUIL CONDITIONS ARE EXPECTED OVERNIGHT AS A
STABLE AIR MASS REMAINS IN PLACE. AS THE LOW LEVELS DECOUPLE
OVERNIGHT, WEAK DRAINAGE FLOW WILL DEVELOP. OVERALL, THE SHORT
TERM FORECAST IS ON TRACK WITH JUST MINOR TWEAKS TO THE HOURLY
GRIDS TO BETTER REFLECT THE LATEST TRENDS.
PREV DISCUSSION... /ISSUED 726 PM EDT WED APR 11 2012/
AVIATION...
VFR CONDITIONS EXPECTED THROUGH THE END OF THE TAF PERIOD. SEA
BREEZE MOVED INLAND ACROSS ALL BUT KPBI THIS AFTERNOON. A LIGHT
SOUTH TO SOUTHEAST FLOW WILL CONTINUE FOR AN HOUR OR SO AT MOST OF
THE EAST COAST TAF SITES BEFORE A DRAINAGE FLOW DEVELOPS. A WEAK
COLD FRONT WILL MOVE INTO THE REGION LATE TONIGHT INTO THE DAY ON
THURSDAY...AND THE WINDS WILL SHIFT TO THE NORTHEAST...AND THEN
EAST IN THE AFTERNOON AS THE SEA BREEZE DEVELOPS. A BIT MORE LOW
LEVEL MOISTURE ON THURSDAY DUE TO THE WEAK FRONT MAY LEAD TO
ISOLATED SHOWERS OR THUNDERSTORMS DEVELOPING NEAR THE EAST COAST
TAF SITES THURSDAY AFTERNOON. SO ADDED VCSH AFTER 18Z FOR MOST OF
THE EAST COAST TAF SITES.
PREV DISCUSSION... /ISSUED 237 PM EDT WED APR 11 2012/
DISCUSSION...A MID/UPPER LEVEL TROUGH OVER FLORIDA WILL PULL OUT
AND BE REPLACED BY A RIDGE OVER THE WEEKEND AND INTO THE EARLY TO
MIDDLE PART OF NEXT WEEK. A WEAK SURFACE COLD FRONT NOW OVER NORTH
CENTRAL FLORIDA WILL MOVE DOWN THE STATE AND ACROSS SOUTH FL WHILE
BECOMING DIFFUSE ON THU-THU NIGHT. A SLIGHT INCREASE IN MOISTURE
ASSOCIATED WITH THIS WEAK FEATURE SHOULD ALLOW FOR ISOLATED
SHOWERS TO DEVELOP ACROSS THE INTERIOR AND EAST COAST ON
THURSDAY, ALONG WITH THE POTENTIAL FOR A FEW THUNDERSTORMS. THIS
AFTERNOON IT LOOKS LIKE THE LACK OF MOISTURE COULD INHIBIT SHOWER
AND POSSIBLE TSTORM DEVELOPMENT ALL TOGETHER. HOWEVER, KEPT THE
SLIGHT CHANCE POPS INTERIOR-EAST GIVEN THE CU FIELD ON SATELLITE
IMAGERY AND THE HRRR CONTINUING TO SHOW SOME DEVELOPMENT.
CONFIDENCE IN DEVELOPMENT IS LOW THIS AFTERNOON WITH MODERATE
CONFIDENCE FOR THURSDAY.
THE FRONTAL BOUNDARY WILL WEAKEN THU NIGHT-FRI...BUT JUST ENOUGH
MOISTURE MAY REMAIN ACROSS SOUTHEAST AREAS TO ALLOW FOR A FEW
SHOWERS TO MOVE ONSHORE THE ATLANTIC COAST ON AN INCREASING
NE WIND FLOW. SO ADDED A SLIGHT CHANCE OF SHOWERS FOR BROWARD
/MIAMI-DADE FRI.
A BUILDING RIDGE OVER THE WEEKEND AND INTO THE EARLY TO MIDDLE
PART OF NEXT WEEK WILL RESULT IN A TRANQUIL WEATHER REGIME. GFS
AND ECMWF ARE IN AGREEMENT ON THIS.
RIP CURRENTS WILL BECOME AN INCREASING CONCERN AT THE ATLANTIC
BEACHES THIS WEEKEND AND INTO NEXT WEEK DUE TO THE INCREASING
ONSHORE WIND FLOW.
SLIGHTLY COOLER TEMPS AND DEWPOINTS IN THE 50S OVER THE WEEKEND
WILL GRADUALLY INCREASE NEXT WEEK AS WINDS TURN SOUTHEAST.
MARINE...LOW WINDS/SEAS WILL CONTINUE UNTIL WINDS INCREASE BEHIND
THE FRONT ESPECIALLY THIS WEEKEND. THIS WILL LEAD TO INCREASE SEAS
ESPECIALLY IN THE GULF STREAM OVER THE WEEKEND. WINDS COULD
APPROACH SMALL CRAFT ADVISORY CONDITIONS IN THE ATLANTIC THIS
WEEKEND...NEAR 20 KT.
FIRE WEATHER...MIN RELATIVE HUMIDITIES BELOW 35 PERCENT WILL
OCCUR OVER GLADES, HENDRY, AND INLAND COLLIER COUNTIES THIS
AFTERNOON WHERE A FIRE DANGER STMT REMAINS IN EFFECT. RH`S WILL
MODIFY A BIT THU-FRI BUT STILL COULD FALL DOWN TO NEAR CRITICAL
LEVELS SO THIS WILL NEED TO BE MONITORED.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 65 81 66 / 20 20 10 10
FORT LAUDERDALE 83 69 82 69 / 20 20 20 20
MIAMI 84 68 82 68 / 20 20 20 20
NAPLES 85 63 84 62 / 10 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...55/CWC
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
134 AM EDT THU APR 12 2012
.SYNOPSIS...
COOL AND DRY HIGH PRESSURE WILL GRADUALLY BUILD INTO THE REGION
THROUGH THE LATTER PART OF THE WEEK. OVER THE WEEKEND...THE HIGH
WILL SLIDE OFF THE SOUTHEAST COAST AND REMAIN THERE THROUGH EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
A SECONDARY DRY FRONT MOVING N TO S OVER THE FORECAST AREA ALLOWING
FOR SURGING NE WINDS...ESPECIALLY COASTAL AREAS. DESPITE THE
WINDS...TEMPS WERE CONTINUING TO FALL. WINDS COULD DECOUPLE LATE
OVER FAR INLAND AREAS ALLOWING FOR SOME PATCHY FROST. LOWS TEMPS
ON TRACK.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
A DEEP LAYER RIDGE WILL CONTINUE TO BUILD ACROSS THE AREA FROM THE
WEST AS A STRONG UPPER LEVEL TROUGH AXIS MOVES EASTWARD INTO THE
ATLANTIC THROUGH THE PERIOD. TEMPERATURES WILL BE BELOW
NORMAL...ESPECIALLY MIN TEMPS FOR THURSDAY...AND FRIDAY THEN
MODERATING TO ABOVE NORMAL BY SATURDAY.
THURSDAY...MODERATELY STRONG HIGH PRESSURE...CENTERED OVER THE OH
RIVER VALLEY...WILL EXTEND ACROSS THE ENTIRE SE U.S.. AFTER A COLD
MORNING START...THE COLD ADVECTION SHOULD BE OVER BY EARLY IN THE
DAY. HOWEVER...MAX TEMPS STILL NOT EXPECTED TO GET OUT OF THE UPPER
60S NORTH TO LOWER 70S SOUTH WITH SUNNY SKIES AND LIGHT ENE WINDS.
THURSDAY NIGHT...A SURFACE HIGH PRESSURE RIDGE WILL BE RIGHT OVER
THE AREA WITH LIGHT TO CALM WINDS AND CLEAR SKIES. THIS WILL SETUP
VERY GOOD RADIATIONAL CONDITIONS...AND HAVE GONE A DEG OR TWO BELOW
LATEST GUIDANCE. NOT THINKING THERE WILL BE ANY WIDESPREAD FREEZING
TEMPERATURES INLAND...BUT THERE COULD BE SOME PATCHY TO SCATTERED
FROST WELL INLAND. THE FROST FORECAST WILL LARGELY DEPEND ON HOW
MUCH THE SURFACE TDS RECOVER OVERNIGHT. LATEST GUIDANCE...EVEN FOR
INLAND LOCATIONS...SHOWS TDS ABOVE FREEZING. GIVEN THE MARGINAL
NATURE AND UNCERTAINTY...HAVE NOT YET ADDED ANY FROST TO THE
FORECAST.
FRIDAY...MODELS ARE SHOWING A SHORTWAVE MOVING DOWN THE BACK SIDE OF
THE UPPER TROUGH OVER THE ATLANTIC IN THE MORNING...THEN IT MOVES
OFF THE MID ATLANTIC COAST WELL NORTH OF US BY AFTERNOON. THIS
FEATURE SEEMS TO REINFORCE THE SURFACE RIDGE...CENTERED OVER THE
NORTHERN AREA BY AFTERNOON. 850 MB TEMPS ARE A FEW DEGS WARMER...
THUS EXPECT MAX TEMPS TO REFLECT THIS WITH HIGHS IN THE LOWER 70S
AWAY FROM THE IMMEDIATE COAST. LIGHT NE WINDS WILL VEER TO ESE BY
LATE DAY...WHICH WILL HOLD TEMPS IN THE MID TO UPPER 60S RIGHT AT
THE SHORE.
FRIDAY NIGHT...THE SURFACE RIDGE WILL SHIFT TO ENE OF THE REGION
THROUGH THE NIGHT...WHICH WILL KEEP LOW LEVEL FLOW ESE. THIS WILL
MODERATE TEMPS...WITH LOWS GENERALLY IN THE 40S TO NEAR 50...WHICH
IS STILL BELOW NORMAL.
SATURDAY...THE MID AND UPPER LEVEL RIDGE AXIS WILL BE JUST WEST OF
THE REGION WITH THE SURFACE RIDGE CENTERED OFFSHORE. THIS WILL SETUP
A SE LOW LEVEL FLOW AND CONTINUED MODERATION OF TEMPERATURES. EXPECT
HIGHS TO BE A FEW DEGS ABOVE NORMAL...IN THE MID TO UPPER 70S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
FORECAST AGREEMENT IS PRETTY GOOD IN THE LONG TERM PERIOD. THE LARGE
UPPER RIDGE WILL STRENGTHEN ACROSS THE SOUTHEASTERN US THROUGH EARLY
NEXT WEEK. EVENTUALLY A CLOSED UPPER ANTICYCLONE WILL DEVELOP AND
SIT DIRECTLY OVER THE SOUTHEAST COAST. THE RIDGE WILL GRADUALLY
SHIFT EASTWARD THROUGH TUESDAY AND BEGIN TO GIVE WAY TO A TROF
APPROACHING FROM THE WEST FOR THE MID WEEK TIME PERIOD. THE SURFACE
HIGH WILL SETTLE OVER THE WESTERN ATLANTIC AND WILL SUPPORT A
DEVELOPING WARM SOUTHERLY RETURN FLOW INTO EARLY NEXT WEEK. WITH
HEIGHTS RISING UNDER THE RIDGE...TEMPS WILL MODERATE NICELY AND
UPPER 80S MAY EVENTUALLY COVER THE AREA FOR MONDAY AND TUESDAY. THE
FORECAST IS DRY AS IT LOOKS LIKE THE NEXT FRONT WILL NOT APPROACH
UNTIL THE WEDNESDAY TIME FRAME.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR AT KCHS/KSAV THROUGH 06Z/12. A BRIEF PERIOD OF GUSTY SURFACE
WINDS TO 20G25 KT NE WINDS AT KSAV SHORTLY AFTER 06Z THIS MORNING
AS A SECONDARY FRONT MOVES S OF THE SAVANNAH RIVER.
EXTENDED AVIATION OUTLOOK...VFR CONDITIONS WILL PREVAIL.
&&
.MARINE...
INCOMING DATA CONTINUE TO SUPPORT SMALL CRAFT ADVISORY CONDITIONS
ALL LEGS OUTSIDE OF THE CHARLESTON HARBOR. THE LATEST RUC EVEN
SUGGESTS A PERIOD OF GALES COULD OCCUR EAST OF THE SAVANNAH RIVER
ENTRANCE LATER TONIGHT. NOT TOO CONFIDENT ON GALES IN THIS
PATTERN...BUT IT WILL HAVE TO BE WATCHED CAREFULLY OVERNIGHT. WILL
MAINTAIN 20-25 KT WITH GUSTS TO 30 KT WITH SEAS BUILDING 3-5 FT
OVERNIGHT...PEAKING 4-6 FT OVER THE GEORGIA OFFSHORE WATERS BY
SUNRISE THURSDAY. SMALL CRAFT ADVISORY CONDITIONS HAVE DEVELOPED
IN THE CHARLESTON HARBOR BUT WINDS EXPECTED TO COME DOWN TO THE
15-20 KT RANGE OVERNIGHT. WE UPDATED OUR FORECAST EARLIER AND
INCREASED WINDS AND MENTIONED 1-2 FT WAVES IN THE HARBOR.
MODERATE TO STRONG HIGH PRESSURE WILL BE CENTERED NORTHWEST OF THE
WATERS TO START OFF THURSDAY. THE PRESSURE GRADIENT WILL BE PINCHED
ENOUGH OVER THE SOUTHERN HALF OF THE WATERS TO SUSTAIN WINDS 15-20
KT WITH SOME HIGHER GUSTS. RIGHT NOW...IT APPEARS THAT WINDS/SEAS
WILL REMAIN BELOW SCA LEVELS. HIGH PRESSURE WILL SETTLE OVER THE
REGION THURSDAY NIGHT THROUGH FRIDAY WITH LIGHT WINDS BECOMING
ONSHORE NEAR THE COAST DURING THE AFTERNOON. SATURDAY THROUGH
MONDAY...HIGH PRESSURE WILL BE MAINLY EAST OF THE REGION WITH SSE
LOW LEVEL FLOW OF 15 KT OR LESS AND SEAS 4 FT OR LESS.
&&
.FIRE WEATHER...
LATEST GUIDANCE CONTINUES TO INDICATE THAT AFTERNOON MINIMUM RH
VALUES WILL BE 20-25 PERCENT OVER INTERIOR LOCATIONS FOR THURSDAY
AFTERNOON. A FIRE DANGER STATEMENT WILL BE ISSUED LATER TONIGHT
FOR MOST AREAS. LOW LEVEL MOISTURE AND TEMPERATURES GRADUALLY
INCREASE BY LATE WEEK AND THROUGH THE WEEKEND. NOT EXPECTING ANY
CRITICAL RH OR WIND ISSUES FRIDAY THROUGH THE WEEKEND.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR AMZ352.
SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR AMZ374.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR
AMZ350.
SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR AMZ354.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...RFM
LONG TERM...BSH
AVIATION...
MARINE...
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS CARIBOU ME
328 AM EDT THU APR 12 2012
.SYNOPSIS...
SECONDARY LOW PRESSURE SOUTHEAST OF NOVA SCOTIA WILL SLOWLY
TRACK EAST INTO THE OPEN ATLANTIC BY EVENING. HIGH PRESSURE WILL
GRADUALLY BUILD EAST TONIGHT THROUGH FRIDAY. A WARM FRONT WILL
APPROACH FROM THE WEST SATURDAY AND CROSS THE REGION SATURDAY
NIGHT... FOLLOWED BY A COLD FRONT FROM CENTRAL CANADA SUNDAY
NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
MOST MODELS INDICATE LITTLE IF ANY SHWRS TO AFFECT OUR FA
TDY...YET LATEST RADAR REF IMAGERY SHOWS ISOLD-SCT SHWRS OVR E
CNTRL AND DOWNEAST PTNS OF THE FA...WITH MORE INTENSE AND GREATER
CVRG OF SHWRS JUST OVR THE BORDER IN NB PROV. HRRR FCST REF SHOWS
THE MORE INTENSE SHWRS WEAKENING BEFORE CROSSING WWRD INTO E CNTRL
AND SE ME THIS MORN...BUT SHOWS ADDITIONAL RN SHWRS DEVELOPING OVR
E CNTRL AND DOWNEAST PTNS OF THE FA THIS AFTN DUE TO DESTABILIZATION
OF THE LOWER ATMOSPHERE UNDER THE EXITING UPPER LVL LOW. WITH THIS
IN MIND...WE BROUGHT SCT SHWRS FURTHER N THIS MORN INTO ERLY AFTN
THAN PREVIOUS UPDATES. FCST LOW VALUES OF 6HRLY QPF THRU THIS EVE
WAS BASED ON INCREMENTAL INTERVALS OF POP VALUES...AND IS RATHER A
POTENTIAL OF QPF WITH INDIVIDUAL SHWRS OVR PARTICULAR LOCATIONS
RATHER THAN AN ACTUAL FCST GRADIENT OF QPF ACROSS THIS PTN OF THE
FA.
OTHERWISE...WINDS WILL BE BREEZIER ACROSS THE FA TDY...SPCLY N AND
W WHERE WIND GUSTS UP TO 20 MPH IS XPCTD. HI TEMPS WILL SHOW LESS
N-S GRADIENT THAN TYPICAL THIS TM OF SEASON DUE TO XPCTD GREATER
SUNSHINE POTENTIAL ACROSS THE N BY AFTN. ANY REMAINING SHWRS ERLY
THIS EVE SHOULD DISSIPATE OR MOVE ESE OF DOWNEAST PTNS OF THE FA
BY LATE TNGT. WINDS ACROSS WRN/NRN/CNTRL VLY PTNS OF THE FA COULD
DECOUPLE LATE TNGT UNDER CLRG SKIES...ALLOWING SOME RADIATIONAL
COOLING AND SFC BASED INVSNS RESULTING IN COOLER OVRNGT LOWS OVR
THESE AREAS AS COMPARED TO RECENT PRIOR NGTS
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
HIGH PRESSURE BUILDS FRIDAY WITH A NORTHWESTERLY FLOW. GENERALLY
SUNNY SKIES ARE EXPECTED ACROSS THE FORECAST AREA WITH JUST
SCATTERED THIN CUMULUS AND SOME AFTERNOON CIRRUS. HIGHS SHOULD
REACH THE LOW 50S NORTH AND UPPER 50S DOWN EAST WITH LOW HUMIDITY.
TEMPERATURES WILL CONTINUE TO MODERATE SATURDAY WITH WARM AIR
ADVECTION AND WINDS BACKING TO A MORE WEST TO SOUTHWEST FLOW.
HIGHS WILL REACH THE UPPER 50S NORTH AND LOW 60S DOWN EAST. CLOUDS
WILL INCREASE DURING THE AFTERNOON AS A WEAK WARM FRONT APPROACHES
FROM QUEBEC.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
SOME LIGHT RAIN IS POSSIBLE SATURDAY NIGHT AS A WARM FRONT CROSSES
THE FORECAST AREA. THE FRONT WILL HAVE MOVED OUT OF THE AREA BY
SUNDAY MORNING AND SHOULD SET THE STAGE FOR A WARM AND WINDY DAY
WITH HIGHS REACHING NEAR 60F NORTH AND MID TO UPPER 60S DOWN
EAST...EXCEPT NEAR THE COAST WHERE AN ONSHORE FLOW WILL LIMIT
HIGHS TO THE 50S. SUNSHINE WILL BE SOMEWHAT LIMITED...ESPECIALLY
TOWARDS THE CROWN OF MAINE AS A STRONG COLD FRONT WILL APPROACH
THE THE SJV DURING THE AFTERNOON AND MOVE SOUTH ACROSS THE
FORECAST AREA SUNDAY AFTERNOON AND EVENING. THIS FRONT COULD
PRODUCE SOME LOW-TOPPED CONVECTION BRINGING STRONG GUSTY WINDS TO
THE SURFACE OVER 30 KTS. WITH THE FRONT THROUGH THE AREA...A SUNNY
AND WINDY DAY FOLLOWS FOR MONDAY. THE BIGGEST QUESTION WILL BE THE
EXTENT OF THE COLD AIR ADVECTION AND STRENGTH OF WINDS. ONE
SCENARIO WOULD PRODUCE HIGHS IN THE LOW 50S NORTH AND ANOTHER DAY
IN THE MID 60S DOWN EAST. THE OTHER END OF THE SPECTRUM ONLY GIVES
HIGHS NEAR 40F IN THE CROWN OF MAINE AND LOW 50S DOWN EAST. AM
FAVORING A BLEND BETWEEN THESE WITH HIGHS IN THE MID 40S NORTH AND
MID 50S DOWN EAST. EITHER WAY...THIS IS A DRY AIR MASS AND
TEMPERATURES SHOULD COOL INTO THE LOW-MID 20S NORTH AND LOW 30S
DOWN EAST ON MONDAY NIGHT.
THE REMAINDER OF THE PERIOD WILL BE CLOUDY...COOL AND WET AS LOW
PRESSURE MOVES SLOWLY FROM THE GREAT LAKES REGION TOWARDS THE NEW
ENGLAND. THE BIGGEST QUESTION WILL BE WHETHER IT WILL BE COLD
ENOUGH TO SUPPORT SNOW IN NORTHERN ZONES TUESDAY MORNING. THIS
WILL DEPEND ON THE AMOUNT OF COLD AIR ADVECTION BEHIND THE COLD
FRONT SUNDAY NIGHT. WILL GO WITH A CHANCE OF SNOW FOR ZONES 1
THROUGH 6 TUESDAY MORNING.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
NEAR TERM: MAINLY LOW TO MID VFR...WITH A BRIEF PD OF MVFR
POSSIBLE ERLY TO MID MORN...SPCLY DOWNEAST SITES WITH ANY SHWRS.
CLDS SHOULD CLR FROM ALL TAF SITES NW TO SE OVRNGT.
SHORT TERM: VFR. CHANCE OF IFR IN AN AFTERNOON OR EVENING RAIN
SHOWER SUNDAY...ACCOMPANIED BY WEST WINDS GUSTING OVER 30 KTS.
&&
.MARINE...
NEAR TERM: NO HDLNS ANTICIPATED THRU TNGT...WITH NW WINDS OF 10 TO
20 KT DIMINISHING LATE TDY THRU TNGT. WE USED A BLEND OF 00Z NAM12...
GFS40 AND GMOS FOR WINDS AND A 50%/30%/20% WW3/SWAN-NAM/SWAN-GFS
FOR WV HTS.
SHORT TERM: GENERALLY BENIGN CONDITIONS EXCEPT A POSSIBLE SCA
SUNDAY AHEAD OF A COLD FRONT. WAVE HTS OVER 5 FEET ARE MORE LIKELY
TO PRODUCE AN SCA DURING THIS PERIOD RATHER THAN WINDS OVER 25 KTS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...VJN
SHORT TERM...MCW
LONG TERM...MCW
AVIATION...VJN
MARINE...VJN/MCW
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
140 AM EDT THU APR 12 2012
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE SUNSHINE AND MODERATE TEMPERATURES
THROUGH FRIDAY. UNSETTLED CONDITIONS ARE FORECAST WITH A WEEKEND
FRONTAL SYSTEM.
&&
.NEAR TERM /THROUGH TODAY/...
HAVE REMOVED MENTION OF PRECIPITATION AS LIGHT ACTIVITY HAS
DIMINISHED. HAVE ALSO MADE ADJUSTMENTS TO SKY CONDITIONS AS SKIES
HAVE CLEARED ACROSS MOST OF THE REGION, WITH THE EXCEPTION OF THE
FAR EAST. WILL GO WITH A MAINLY CLEAR SKY FOR THE REMAINDER OF THE
NIGHT. AM CONCERNED THAT SOME SC COULD REDEVELOP TOWARD DAWN, AS
THERE WILL BE WEAK MID-LEVEL CAA. HOWEVER THE WIND FLOW LOOKS TO
BE TOO NORTHERLY. LATEST HRRR MODEL IS SHOWING LOWER CLOUDS
DEVELOPING ACROSS THE NORTH BEFORE DAWN, WILL STAY OPTIMISTIC FOR
CLOUDS OVERNIGHT.
WILL KEEP FREEZE WARNING GOING WITH DRIER AIR MOVING IN FROM THE
WEST, WINDS CONTINUING TO DIMINISH, AND MAINLY CLEAR SKIES.
HIGH PRESSURE WILL MOVE IN FROM THE WEST LATER TODAY AND SUPPRESS
FURTHER PRECIPITATION CHANCES. ALTHOUGH CLOUD COVER WILL BE
MINIMAL, COOL NORTHWEST WIND SHOULD OFFSET INSULATION SUFFICIENTLY
TO KEEP HIGHS APPROXIMATELY 5 TO 10 DEGREES BELOW THE SEASONAL
AVERAGES.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
WITH HIGH PRESSURE FORECAST DIRECTLY OVER THE UPPER OHIO REGION
TONIGHT, EXPECT LIGHT WINDS AND NEAR FREEZING TEMPERATURES AGAIN.
FREEZE WATCH CONTINUES FOR MUCH OF THE AREA, EXCLUDING COUNTIES
TO THE SOUTHWEST OF PITTSBURGH.
CLOUDS ARE PROGGED TO BEGIN INCREASING ON FRIDAY NIGHT AS
WARM...MOIST ADVECTION RESUMES IN ADVANCE OF A LOW DEVELOPING
OVER THE PLAINS. PRECIPITATION CHANCES ARE THUS FORECAST TO
INCREASE ON SATURDAY...WITH HIGHER NUMBERS PROJECTED OVER NORTHERN
AND WESTERN COUNTIES.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A WARM FRONT IS PROGGED TO PUSH ACROSS THE FORECAST AREA BY SATURDAY
NIGHT...WITH MUCH OF THE REGION REMAINING IN THE WARM SECTOR ON
SUNDAY. KEPT SMALL POPS FOR SHOWERS MAINLY ACROSS THE NORTH
SUNDAY. PRECIPITATION CHANCES SHOULD INCREASE BY MONDAY INTO
TUESDAY AS A FRONTAL BOUNDARY SAGS SOUTHWARD AND BECOMES NEARLY
STATIONARY ACROSS THE UPPER OHIO VALLEY. A SURFACE WAVE IS
FORECAST TO RIDE ALONG THE FRONT INTO THE EASTERN GREAT LAKES
REGION BY WEDNESDAY...DRAGGING THE COLD FRONT EAST OF THE FORECAST
AREA.
KEPT CHANCE POPS IN THE FORECAST FOR MONDAY THROUGH WEDNESDAY...WITH
TEMPERATURES REMAINING ABOVE NORMAL THROUGH THE PERIOD.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
LAKE-INDUCED CUMULUS SHOULD GRADUALLY CONTINUE TO DISSIPATE OVER THE
RIDGES AROUND KDUJ AND KLBE...LEAVING JUST A FEW CLOUDS OVERNIGHT
EAST...WITH CLEAR SKIES GENERALLY TO THE WEST. NAM PROFILES SUGGEST
CUMULUS DEVELOPMENT AT ALL SITES DURING THE AFTERNOON ON THURSDAY
AOA 5 KFT...MEANING NO FLIGHT CATEGORY RESTRICTIONS.
ADDITIONALLY...ROUGHLY 10 KTS IN THE MIXED LAYER SHOULD YIELD A
BRISK NW WIND THROUGH THE DAY BEFORE THAT IS CURTAILED IN THE
EVENING. AS CUMULUS DISSIPATES WITH THE LOSS OF DAYTIME HEATING ON
THURSDAY...GENERALLY CLEAR SKIES AND LIGHT WINDS SHOULD AGAIN
DOMINATE AT ALL SITES.
OUTLOOK...FRIDAY THROUGH MONDAY...
VFR FRIDAY. WARM FRONT-ASSOCIATED SHOWERS MAY PROVIDE RESTRICTIONS
SATURDAY INTO SUNDAY. A COLD FRONTAL PASSAGE MONDAY WILL INCREASE
SHOWER COVERAGE AND THE POTENTIAL FOR RESTRICTIONS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR MDZ001.
FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
MDZ001.
OH...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR OHZ039>041-
048>050-057>059-068-069.
FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
OHZ041.
PA...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR PAZ007>009-
013>016-020>023-029-031-073>076.
FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
PAZ007>009-013>016-020>023-029-073>076.
WV...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR WVZ001>004-012-
021>023-041.
FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
WVZ001-023-041.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
128 AM EDT THU APR 12 2012
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE SUNSHINE AND MODERATE TEMPERATURES
THROUGH FRIDAY. UNSETTLED CONDITIONS ARE FORECAST WITH A WEEKEND
FRONTAL SYSTEM.
&&
.NEAR TERM /THROUGH TODAY/...
HAVE REMOVED MENTION OF PRECIPITATION AS LIGHT ACTIVITY HAS
DIMINISHED. HAVE ALSO MADE ADJUSTMENTS TO SKY CONDITIONS AS SKIES
HAVE CLEARED ACROSS MOST OF THE REGION, WITH THE EXCEPTION OF THE
FAR EAST. WILL GO WITH A MAINLY CLEAR SKY FOR THE REMAINDER OF THE
NIGHT. AM CONCERNED THAT SOME SC COULD REDEVELOP TOWARD DAWN, AS
THERE WILL BE WEAK MID-LEVEL CAA. HOWEVER THE WIND FLOW LOOKS TO
BE TOO NORTHERLY. LATEST HRRR MODEL IS SHOWING LOWER CLOUDS
DEVELOPING ACROSS THE NORTH BEFORE DAWN, WILL STAY OPTIMISTIC FOR
CLOUDS OVERNIGHT.
WILL KEEP FREEZE WARNING GOING WITH DRIER AIR MOVING IN FROM THE
WEST, WINDS CONTINUING TO DIMINISH, AND MAINLY CLEAR SKIES.
HIGH PRESSURE WILL MOVE IN FROM THE WEST LATER TODAY AND SUPPRESS
FURTHER PRECIPITATION CHANCES. ALTHOUGH CLOUD COVER WILL BE
MINIMAL, COOL NORTHWEST WIND SHOULD OFFSET INSULATION SUFFICIENTLY
TO KEEP HIGHS APPROXIMATELY 5 TO 10 DEGREES BELOW THE SEASONAL
AVERAGES.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
WITH HIGH PRESSURE FORECAST DIRECTLY OVER THE UPPER OHIO REGION
TONIGHT, EXPECT LIGHT WINDS AND NEAR FREEZING TEMPERATURES AGAIN.
FREEZE WATCH CONTINUES FOR MUCH OF THE AREA, EXCLUDING COUNTIES
TO THE SOUTHWEST OF PITTSBURGH.
CLOUDS ARE PROGGED TO BEGIN INCREASING ON FRIDAY NIGHT AS
WARM...MOIST ADVECTION RESUMES IN ADVANCE OF A LOW DEVELOPING
OVER THE PLAINS. PRECIPITATION CHANCES ARE THUS FORECAST TO
INCREASE ON SATURDAY...WITH HIGHER NUMBERS PROJECTED OVER NORTHERN
AND WESTERN COUNTIES.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A WARM FRONT IS PROGGED TO PUSH ACROSS THE FORECAST AREA BY SATURDAY
NIGHT...WITH MUCH OF THE REGION REMAINING IN THE WARM SECTOR ON
SUNDAY. KEPT SMALL POPS FOR SHOWERS MAINLY ACROSS THE NORTH
SUNDAY. PRECIPITATION CHANCES SHOULD INCREASE BY MONDAY INTO
TUESDAY AS A FRONTAL BOUNDARY SAGS SOUTHWARD AND BECOMES NEARLY
STATIONARY ACROSS THE UPPER OHIO VALLEY. A SURFACE WAVE IS
FORECAST TO RIDE ALONG THE FRONT INTO THE EASTERN GREAT LAKES
REGION BY WEDNESDAY...DRAGGING THE COLD FRONT EAST OF THE FORECAST
AREA.
KEPT CHANCE POPS IN THE FORECAST FOR MONDAY THROUGH WEDNESDAY...WITH
TEMPERATURES REMAINING ABOVE NORMAL THROUGH THE PERIOD.
&&
.AVIATION /05Z THURSDAY THROUGH MONDAY/...
TRENDS IN RECENT SURFACE, RADAR, AND SATELLITE DATA, ALONG WITH HRRR
MODEL OUTPUT SHOW REMAINING ISOLATED MVFR INSTABILITY SHOWERS
DISSIPATING BY 04Z. VFR STRATOCUMULUS WILL LIKEWISE ALSO BECOME
SCATTERED.
NORTHWEST WINDS WILL ALSO DECREASE TO 5-8 KTS OVERNIGHT.
NAM MODEL PROFILES SHOW VFR CUMULUS DEVELOPMENT THURSDAY AFTERNOON
AS NORTHWEST WINDS INCREASE TO 12 KTS WITH PEAK GUSTS NO HIGHER THAN
20 KTS.
HIGH PRESSURE WILL PROVIDE VFR CLEAR SKIES WITH LIGHT WINDS THURSDAY
NIGHT.
OUTLOOK...FRIDAY THROUGH MONDAY...
VFR FRIDAY. WARM FRONT-ASSOCIATED SHOWERS MAY PROVIDE RESTRICTIONS
SATURDAY INTO SUNDAY. A COLD FRONTAL PASSAGE MONDAY WILL INCREASE
SHOWER COVERAGE AND THE POTENTIAL FOR RESTRICTIONS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR MDZ001.
FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
MDZ001.
OH...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR OHZ039>041-
048>050-057>059-068-069.
FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
OHZ041.
PA...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR PAZ007>009-
013>016-020>023-029-031-073>076.
FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
PAZ007>009-013>016-020>023-029-073>076.
WV...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR WVZ001>004-012-
021>023-041.
FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR
WVZ001-023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
428 AM EDT THU APR 12 2012
.SYNOPSIS...
ISSUED AT 426 AM EDT THU APR 12 2012
WV IMAGERY AND RUC ANALYSIS INDICATED AN AMPLIFIED PATTERN WITH A
MID/UPPER LEVEL TROUGH INTO THE WRN CONUS A RIDGE OVER THE PLAINS
AND A TROUGH OVER THE EAST RESULTING IN NW FLOW THROUGH THE NRN
GREAT LAKES. A WELL-DEFINED UPSTREAM SHORTWAVE TROUGH WAS LOCATED
OVER NRN ONTARIO NEAR CYPL. AT THE SFC...A RIDGE EXTENDED FROM JAMES
BAY THROUGH THE WRN GREAT LAKES LEAVING CLEAR SKIES...LIGHT WINDS
OVER UPPER MI AND SEASONABLY COOL TEMPS IN THE DRY AIRMASS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 426 AM EDT THU APR 12 2012
TODAY...SINCE A VERY DRY AIRMASS DOMINATED THE REGION...PER 00Z
CYPL/KAPX/KGRB SOUNDINGS ONLY MID/HIGH CLOUDS WERE ASSOCIATED WITH
THE NRN ONTARIO SHRTWV. SIMILARLY...AS THE SHRTWV MOVES THROUGH LAKE
SUPERIOR AND ERN UPPER MI...ONLY MID CLOUDS ARE EXPECTED DESPITE
MODERATE 700-300 MB QVECTOR CONV. WITH A DECENT AMOUNT OF
SUNSHINE...TEMPS SHOULD CLIMB INTO THE MID AND UPPER 50S INLAND
WEST. THE WEAK PRESSURE GRADIENT WILL ALLOW LAKE BREEZES TO
DEVELOP...KEEPING READINGS AOB 50 ALONG THE GREAT LAKES. AFTERNOON
MIXING SHOULD ALSO DROP DEWPOINTS TO AROUND 20 WITH RH AOB 25 PCT
INLAND WEST.
TONIGHT...TEMPS WILL AGAIN DROP BELOW FREEZING IN MOST LOCATIONS AS
LIGHT WINDS PREVAIL AND HIGH CLOUDS ONLY MOVE INTO THE WEST LATE.
SLIGHTLY HIGHER TEMPS ARE EXPECTED WITH DOWNSLOPE SE FLOW WEST NEAR
LAKE SUPERIOR.
FRIDAY INTO FRIDAY NIGHT...MODELS SUGGEST THAT THE TROUGH WILL
ADVANCE TO THE EAST AS A SHORTWAVE LIFTS NE FROM THE PLAINS THROUGH
MN INTO NRN ONTARIO AND THE NRN LAKES. A BAND OF WAA/ISENTROPIC LIFT
ALONG WITH FAVORABLE MOISTURE TRANSPORT SHOULD PRODUCE SCT/NMRS
SHRA MOVING INTO THE WEST LATE FRIDAY AND ACROSS THE CWA FRIDAY
NIGHT. THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE TIMING OF
PCPN MOVING INTO THE AREA. SINCE THE DYNAMICS MOVE THROUGH FAIRLY
QUICKLY...ONLY MODEST PCPN AMOUNTS IN THE 0.10-0.20 INCH RANGE ARE
EXPECTED. WITH ELEVATED CAPE REMAINING SOUTH OF THE AREA...PER
NAM/GFS...NO TSRA ARE EXPECTED.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 426 AM EDT THU APR 12 2012
H925-700 WAA AHEAD OF THE WARM FRONT WILL BE PUSHING NE ACROSS NE
LAKE SUPERIOR AT THE START OF THE PERIOD...WHILE DRY SLOT WORKS OVER
THE REST OF THE CWA DURING THE MORNING HOURS. LLVL MOISTURE LINGERS
IN THE MORNING AND QUICKLY DIMINISHES IN THE AFTN...SO HAVE LOWERED
TO PARTLY CLOUDY IN THE AFTN AHEAD OF NEXT WAVE AND APPROACHING COLD
FRONT FROM THE NW ON SAT NIGHT. AS A RESULT...HAVE DIMINISHED POPS
FROM W TO E DURING THE MORNING HRS AND REMOVED THEM COMPLETELY FOR
THE AFTN. COULD END UP BEING A WARM DAY ON SAT. MIXING TO H925-900
WITH THE DECREASING CLOUDS AND SSW WINDS WOULD LEAD TO HIGHS IN THE
60S TO LOWER 70S. LIKE THE PREVIOUS SHIFT...MADE ANOTHER JUMP IN THE
TEMPS /3-7 DEGREES/ FOR SAT OVER THE WRN TWO THIRDS. THIS COULD EVEN
BE A FEW DEGREES TOO LOW IF THE CLOUDS REALLY CLEAR OUT IN THE AFTN
AND THE WINDS ARE STRONG ENOUGH TO LIMIT LK BREEZES NEAR LK
SUPERIOR.
COLD FRONT ASSOCIATED WITH THE LOW THAT PUSHED THROUGH ONTARIO ON
SAT WILL MOVE SE ACROSS UPPER MI ON SAT NIGHT. THE TIMING OF THIS
FRONT AND A SHORTWAVE/LOW MOVING UP FRONT WILL DETERMINE PCPN
CHANCES FOR SAT NIGHT. WITH THE WAY THE MODELS HAVE BEEN FOR THIS
UPCOMING WEEKEND...LIMITED CONFIDENCE ON PCPN CHANCES BUT CHANCES
OVER THE SRN HALF OF THE CWA SEEM REASONABLE AT THIS POINT. THIS
FRONT SHOULD SLIDE FARTHER SE AND CONTINUE TO DIMINISH PCPN CHANCES
ON SUN.
UNCERTAINTY CONTINUES FARTHER OUT INTO THE FORECAST WITH THE SW FLOW
ALOFT FROM THE UPPER TROUGH OVER THE WRN CONUS. MODELS TRADITIONALLY
HAVE A DIFFICULT TIMING WITH THESE SITUATIONS DUE TO SHORTWAVES OVER
THE PACIFIC HAVING TO ROTATE THROUGH THE UPPER TROUGH AND THE LAST
COUPLE OF DAYS OF RUNS HAVE BEEN NO DIFFERENT.
00Z GEM/GFS/ECMWF COMING INTO BETTER AGREEMENT WITH A LOW PUSHING
OUT OF THE CNTRL/SRN PLAINS ON SUN NIGHT AND INTO THE LOWER GREAT
LKS ON MON AFTN/NIGHT. STILL DIFFERENCES ON THE TIMING/TRACK...BUT
STARTING TO GET A BETTER FEEL ON THIS SYSTEM. THIS WOULD BRING AN
INITIAL SURGE OF WAA PCPN TO THE AREA LATE SUN NIGHT AND INTO MON
/24HRS EARLIER THAN YESTERDAY/...BEFORE THE PCPN REFOCUSES FARTHER
SE AND CLOSER TO THE LOW AND UPPER ENERGY. COLD AIR BEHIND THE COLD
FRONT ON SAT NIGHT AND SUN WILL LEAVE A COLD NEAR SFC LAYER.
ALOFT...HINTS AT A NOSE OF 1C TEMPS BETWEEN H850-700 BUT LIKELY
WON/T BE ENOUGH TO ENTIRELY MELT THE SNOW. WITH THE UNCERTAINTY IN
THE MODELS...FOLLOWED THE MODEL CONSENSUS ON THE 1000-850/850-700
THICKNESS PATTERN AND USED THAT FOR PCPN TYPE. THIS PRODUCES A
RAIN/SNOW MIX WHERE THAT WARM AIR NOSE IS OVER THE FAR SE PART OF
THE CWA AND SNOW ELSEWHERE. MODEL QPF SHOWS THE POTENTIAL FOR
MEASURABLE/ADVISORY SNOW OVER THE WRN CWA ON MON...SO WILL BE
INTERESTING IF THAT CONTINUES ON FUTURE RUNS.
00Z GFS/GEM HOLDING ON TO THE PCPN OVER THE SE HALF OF THE CWA ON
TUES...AS ISENTROPIC ASCENT CONTINUES AROUND THE H850 LOW CENTERED
OVER NRN LK MI. 12Z ECMWF HAS ALREADY MOVED THE HIGH PRESSURE RIDGE
IN BY THIS TIME...SO WILL CONTINUE TO MENTION CHANCES MAINLY OVER
THE SE HALF OF THE CWA. THEN WILL SHOW A DIMINISHING TREND IN PCPN
ON TUES NIGHT AND WED. RIGHT NOW...00Z GFS SHOWING HIGH PRESSURE
RIDGE MOVING OVER THE AREA AT THAT TIME. 12Z ECMWF IS FASTER WITH AN
APPROACHING COLD FRONT AND MOVES IT THROUGH ON WED MORNING BUT THE
00Z RUN BACKED OFF ON THAT POTENTIAL. WILL GO WITH A MAINLY DRY
FORECAST FOR WED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 133 AM EDT THU APR 12 2012
WITH HIGH PRESSURE DOMINATING...VFR CONDITIONS WILL PERSIST THROUGH
THE FCST PD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 426 AM EDT THU APR 12 2012
HIGH PRESSURE WILL COVER THE UPPER GREAT LAKES REGION TODAY AND
TONIGHT...LEADING TO WINDS BELOW 20KTS. A LOW PRESSURE SYSTEM
TAKING SHAPE OVER THE GREAT PLAINS WILL MOVE NORTHEAST ON FRIDAY
AND INTO ONTARIO ON SAT. WINDS WILL SHIFT TO THE SE...BUT THE
MARINE LAYER SHOULD KEEP WINDS FROM EXCEEDING 20KTS. THIS MARINE
LAYER WILL REMAIN IN PLACE UNTIL A COLD FRONT MOVES THROUGH ON
SATURDAY NIGHT. THIS WILL SHIFT THE WINDS TO THE NW UP TO 25KTS ON
SUN.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...MCB
MARINE...SRF
AREA FORECAST DISCUSSION
NWS TULSA OK
1158 PM CDT WED APR 11 2012
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
CHANCES FOR SHOWERS AND THUNDERSTORMS INCREASE DURING THE DAY
THURSDAY AS A SECONDARY WARM FRONT PUSHES NORTHEAST THROUGH THE
REGION. HIGHER CHANCES LOOK TO BE ACROSS EASTERN OKLAHOMA...THUS
WILL CONTINUE THE PROB30 GROUPS FOR EASTERN OKLAHOMA TAF SITES.
OTHERWISE BROKEN TO OVERCAST CEILINGS WILL BE COMMON DURING THE
TAF PERIOD WITH BREEZY WINDS SHIFTING OUT OF THE SOUTHEAST DURING
THE DAY THURSDAY. VFR CONDITIONS SHOULD PREVAIL THROUGH THE
PERIOD...WITH THE POSSIBILITY OF BRIEF PERIODS OF MVFR CONDITIONS
WITHIN ANY CONVECTION.
&&
.PREV DISCUSSION... /ISSUED 927 PM CDT WED APR 11 2012/
DISCUSSION...
EASTERN OK AND NORTHWEST AR REMAIN ON THE COOL AND STABLE SIDE OF
A STATIONARY FRONT DRAPED FROM NE TX TO THE NORTHERN TX PANHANDLE.
CLUSTERS OF STORMS CURRENTLY IN THE PANHANDLE REGION ARE FORECAST
TO SLOWLY WORK THEIR WAY EAST INTO WEST/NORTHWEST OK TONIGHT AS
WARM ADVECTION INCREASES DUE TO STRENGTHENING LLJ OVER THE HIGH
PLAINS. CHANCES ARE QUITE LOW THAT THIS ACTIVITY WILL MAKE IT ALL
THE WAY OVER INTO NORTHEAST OK BY 12Z. THE NEW 00Z NAM AND THE
LATEST RUNS OF THE HRRR SUGGEST IT WILL STAY WEST. THE SREF AND
OTHER ENSEMBLE GUIDANCE KEEP LOW POPS IN THE FAR WEST. THUS...I
WILL TREND THE FORECAST THAT WAY...KEEPING ONLY A LOW SLGT CHC POP
MAINLY WEST OF HWY 75. ALSO MADE A SLIGHT DOWNWARD TWEAK TO THE
LOWS AS PARTLY CLOUDY TO MOSTLY CLEAR SKIES HAS ALLOWED TEMPS TO
DROP OFF THIS EVENING. CLOUDS SHOULD INCREASE SOME AFTER MIDNIGHT
HOWEVER...AND THIS WILL PREVENT A SIGNIFICANT DROP IN TEMPS
TONIGHT. UPDATED PRODUCTS HAVE BEEN SENT.
LACY
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 53 69 61 76 / 10 40 20 20
FSM 49 67 53 78 / 10 20 10 10
MLC 53 70 62 77 / 10 30 10 20
BVO 49 68 59 76 / 10 50 30 30
FYV 43 64 53 75 / 10 20 20 10
BYV 42 64 51 75 / 10 20 20 10
MKO 51 69 57 76 / 10 30 20 20
MIO 46 65 55 75 / 10 30 30 20
F10 52 70 61 76 / 10 30 20 20
HHW 54 71 59 77 / 10 20 10 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...20
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1022 PM MDT WED APR 11 2012
.AVIATION...06Z TAF FORECAST
BREEZY/WINDY CONDITIONS WILL CONTINUE TONIGHT. AREA OF ST OVER
THE SD PLAINS/SOUTHEAST WY WILL EXPAND TONIGHT BRINGING AREAS OF
MVFR CIGS. -SHRA ARE POSSIBLE OVERNIGHT WITH ISOLATED -TSRA.
CONDITIONS WILL IMPROVE FROM SOUTHWEST TO NORTHEAST THURSDAY AS
WINDS GAIN A WESTERLY COMPONENT.
&&
.PREV DISCUSSION... /ISSUED 849 PM MDT WED APR 11 2012/
UPDATE...02Z SURFACE ANALYSIS HAD LOW OVER WESTERN WY WITH HIGH
OVER MN/IA AND DECENT GRADIENT OVER THE CWA. DIURNAL EFFECTS
ALLOWING BOUNDARY LAYER TO DECOUPLE SOME THIS EVENING AND THUS WINDS
HAVE SLACKENED ENOUGH OVER NORTHWEST SD TO ALLOW THE WIND ADVISORY
TO EXPIRE.
00Z KUNR SOUNDING SHOWED LARGE INVERSION WITH VERY SHALLOW
MOISTURE LAYER AROUND 750MB...WHICH IS ALSO THE BASE OF ABOUT
961J/KG MUCAPE. LOW LEVEL JET HAS BEEN UNABLE TO TAP INTO
MUCAPE...LIKELY BECAUSE THE LAYER IS SO THIN. MOISTURE IS
RESPONSIBLE FOR ST EAST/SOUTH OF THE BLACK HILLS PER FOG PRODUCT.
LOOKING UPSTREAM...SPEED MAX/SHORTWAVE OVER EASTERN UT MAKING IT/S
WAY NORTH. 18Z/21Z/00Z RUC HAVE PAINTED SLOWER START TO POPS IN
THE CWA TONIGHT...AND 00Z NAM FOLLOWS THIS TREND AS WELL AS
IR/REGIONAL RADAR LOOPS. WILL PULL BACK NORTHEAST EXTENT OF POPS
TONIGHT. BUT AS SHORTWAVE REACHES WY CWA FROM 06Z-09Z...SHOULD
SEE ELEVATED -SHRA/ISOLATED -TSRA DEVELOP AND QUICKLY MOVE
NORTHEAST ACROSS THE CWA THROUGH THURSDAY MORNING.
UPDATED FORECAST WILL REFLECT THESE THOUGHTS.
PREV DISCUSSION... /ISSUED 300 PM MDT WED APR 11 2012/
DISCUSSION...CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE OVER
EAST-CENTRAL ID...WITH SECONDARY AREA OF LOW PRESSURE OVER
SOUTHWESTERN WY. HIGH PRESSURE REMAINS IN PLACE EAST OF THE
AREA...OVER THE FAR EASTERN DAKOTAS AND MN. UPPER LEVEL ANALYSIS
SHOWS STRONG RIDGE IN PLACE OVER THE HIGH PLAINS...WITH LONGWAVE
TROF ALONG THE WEST COAST. STRONGER SHORTWAVE IS IN PLACE OVER
SOUTHERN NV...MOVING NORTHEAST ALONG BACK SIDE OF THE RIDGE.
ANOTHER WEAKER SHORTWAVE IS NOTED OVER CO...MOVING NORTH-
NORTHEASTWARD. GUSTY SOUTH TO SOUTHEAST WINDS ARE IN PLACE OVER
MUCH OF THE AREA...WITH THE STRONGEST WINDS OVER NORTHWESTERN SD.
SKIES ARE MOSTLY SUNNY ACROSS MUCH OF THE AREA...EXCEPT PARTLY
SUNNY/MOSTLY CLOUDY ACROSS SOUTHWESTERN SD. TEMPS RANGE FROM THE
MID TO UPPER 50S OVER THE BLACK HILLS TO NEAR 70 OVER CAMPBELL
COUNTY WY.
AN UNSETTLED WEATHER PATTERN WILL DEVELOP OVER THE AREA TONIGHT
AND PERSIST THROUGH THE WEEKEND AS TROF ALONG THE WEST COAST MOVES
EAST AND ALLOWS A SERIES OF WEATHER SYSTEMS TO CROSS THE REGION.
THE BETTER CHANCES FOR PCPN IN THE NEAR TERM WILL BE LATER TONIGHT
INTO EARLY THURSDAY...AND AGAIN LATER THURSDAY NIGHT INTO FRIDAY.
AFTER A WARM DAY IN MOST AREAS ON THURSDAY...A GRADUAL COOLING
TREND CAN BE EXPECTED INTO THE WEEKEND AS WELL.
FOR TONIGHT...WINDS WILL REMAIN GUSTY INTO THE EVENING IN MOST
AREAS...WITH THE GUSTY WINDS LINGERING THROUGH MUCH OF THE NIGHT
ACROSS NORTHWESTERN SD. HAVE DECIDED TO CANCEL THE WIND ADVISORY
FOR THE SOUTHWESTERN SD PLAINS AS WINDS HAVE STAYED BELOW ADVISORY
CRITERIA AND GENERALLY WILL INTO THIS EVENING. CHANCES FOR SHOWERS
AND A FEW THUNDERSTORMS WILL INCREASE FROM THE SOUTHWEST THIS
EVENING AS SHORTWAVE OVER CO MOVES ACROSS THE AREA. BEST CHANCES
WILL BE ACROSS THE BLACK HILLS AREA AND EASTWARD DURING THE
OVERNIGHT INTO THURSDAY MORNING. TEMPS WILL REMAIN RELATIVELY
MILD...WITH LOWS IN THE UPPER 30S AND 40S.
THE MAIN SHORTWAVE IS PROGGED TO EXIT THE AREA IN THE MORNING...
WITH SOUTHWESTERLY FLOW ALOFT REMAINING IN PLACE. WEAKER IMBEDDED
ENERGY IN THE FLOW COULD BRING ISOLATED SHOWERS AND STORMS IN THE
AFTERNOON...BUT MOST AREAS WILL LIKELY REMAIN DRY. SOUTHWESTERLY
WINDS ACROSS MUCH OF THE AREA WILL BRING WARMER AIR IN AHEAD OF
APPROACHING FRONT...WITH HIGHS IN THE 60S AND LOWER 70S...WARMEST
SOUTH AND EAST OF THE BLACK HILLS.
MODELS BEGIN TO DIVERGE FOR THURSDAY NIGHT AND BEYOND AS LOW
PRESSURE AND COLD FRONT CROSS THE AREA. THERE IS RELATIVELY LOW
CONFIDENCE IN THE FORECAST THROUGH THE WEEKEND. RIGHT NOW...THE
MAIN CHANCES FOR SHOWERS THURSDAY NIGHT LOOK TO BE ACROSS
NORTHEASTERN WY...THE BLACK HILLS AND TOWARD CENTRAL SD. A FEW
THUNDERSTORMS ARE POSSIBLE...ESPECIALLY TOWARD SOUTH CENTRAL SD.
TEMPS SHOULD BE COLD ENOUGH OVERNIGHT AND EARLY FRIDAY FOR SNOW
SHOWERS OVER THE HIGHER BLACK HILLS. LOWS WILL BE IN THE MID 30S
TO MID 40S AT MOST LOCATIONS.
SOUTHWESTERLY FLOW ALOFT REMAINS OVER THE AREA ON FRIDAY...WITH
ADDITIONAL UPPER LEVEL DISTURBANCES IN THE FLOW LIKELY ALLOWING
SOME SHOWERS AND ISOLATED STORMS TO DEVELOP...ESPECIALLY DURING
THE AFTERNOON AND EVENING HOURS. CONSENSUS OF THE MODELS HAS THE
MAJORITY OF ACTIVITY DEVELOPING OVER THE BLACK HILLS AREA...SO
WILL KEEP HIGHEST POPS IN THAT AREA. HIGHS LOOK TO BE IN THE UPPER
50S TO MID 60S AT MOST LOCATIONS...50S ACROSS THE BLACK HILLS.
EXTENDED...LARGE UPPER TROUGH WILL KEEP COOL AND UNSETTLED WEATHER
OVER THE NORTHERN PLAINS FROM SATURDAY THROUGH TUESDAY. A SERIES OF
UPPER WAVES WILL ROTATE OUT OF THE TROUGH AND CROSS THE NORTHERN
PLAINS DURING THIS PERIOD. MODEL SOLUTIONS CONTINUE TO DIFFER IN THE
DETAILS. FOR NOW WILL CONTINUE WITH A BLEND OF THE LATEST SOLUTIONS
AND BROAD BRUSH PRECIP CHANCES. TEMPERATURES MAY BE COLD ENOUGH AT
THE HIGHER ELEVATIONS FOR SOME LIGHT SNOW ACCUMULATIONS BOTH
SATURDAY NIGHT AND SUNDAY NIGHT. TEMPERATURES WILL BE NEAR OR
SLIGHTLY COOLER THAN NORMAL THROUGH TUESDAY.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1109 PM CDT WED APR 11 2012
.AVIATION...
AVIATION CONCERNS CONTINUE OVER THE PATH AND LONGEVITY OF THIS
EVENING/S CONVECTION IN THE PANHANDLE. HRRR AND OUNWRF ARE MORE
EAGER ABOUT BRINGING AN MCS EASTWARD...BUT NAM/GFS AND LOCAL WRF
ARE NOT. FORECAST SOUNDINGS IN THE METROPLEX DO NOT HAVE A LOT OF
ELEVATED INSTABILITY TO SUPPORT TSRA PROPAGATION...SO FEEL THAT
ANYTHING THAT REACHES METROPLEX SHOULD BE ON THE WANE. HAVE ADDED
VCSH TO MORNING GROUPS TO ACCOUNT FOR CONVECTIVE REMNANTS IF THEY
SURVIVE/ARRIVE. 84
&&
.UPDATE...
OLD FRONTAL BOUNDARY COMBINED WITH WEAK OUTFLOW FROM LATE DAY
STORMS NORTH AND EAST OF THE DFW METRO EARLIER HAS NOW SLID WEST
AS A FAIRFIELD...CORISCANA...FORT WORTH...AND BRIDGEPORT LINE...
WITH A DRIER AND SLIGHTLY COOLER AIRMASS BEHIND IT WITH EAST
WINDS 10 TO 15 MPH. HAVE LOWERED OVERNIGHT LOWS 2-4 DEGREES
BEHIND THE BOUNDARY WITH LESS COULD COVER AND WINDS EXPECTED TO
SUBSIDE. AREAS FURTHER SOUTH AND WEST WILL CONTINUE SOUTHEAST
AROUND 10 MPH OVERNIGHT WITH SLIGHTLY HIGHER SURFACE DEW PTS.
MODELS OUTSIDE OF THE NAM12/HRRR ARE WAY OVERDOING EXPECTED
CONVECTION DUE TO BEING TOO UNSTABLE AND TOO FAST WITH FORWARD
PROPAGATION OF STORMS OCCURRING ACROSS TX PANHANDLE AND WESTERN
SOUTH PLAINS. 00Z FWD SOUNDING ALSO INDICATING BARELY AN INCH OF
PWAT WITH ONLY 400 J/KG CAPE...WITH BEST LAPSE RATES NEAR 7 DEG
C/KM REMAINING ACROSS WESTERN RED RIVER VALLEY AND FAR WESTERN
COUNTIES OVERNIGHT.
WILL CARRY A CHANCE FOR SHOWERS AND NON-SEVERE STORMS BETWEEN 09Z-
15Z THURSDAY MORNING NW OF A SHERMAN...DECATUR...MINERAL WELLS LINE
WITH A ISOLATED COVERAGE AS FAR SOUTHEAST AS A DFW METRO TO
GOLDTHWAITE LINE LATE TONIGHT. AGAIN...WEAK WIND THROUGH 500MB
...SEMI-MOIST ADIABATIC THERMODYNAMIC PROFILES...AND A WEAK LLJ
INDICATE STORMS WILL WEAKEN CONSIDERABLY BEFORE AFFECTING AREAS
WEST THROUGH NORTH OF DFW AROUND DAYBREAK. HAVE ADJUSTED POPS
ACCORDINGLY THROUGH MIDDAY THURSDAY.
05/
&&
.PREV DISCUSSION... /ISSUED 315 PM CDT WED APR 11 2012/
SCATTERED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ALONG A WEAK
SURFACE FRONT JUST TO THE NORTHEAST OF THE DALLAS-FORT WORTH AREA
THIS AFTERNOON. THE BOUNDARY EXTENDED ALONG A LINE FROM AROUND
BOWIE TO PLANO TO CANTON AT 3 PM AND CONTINUES TO SAG SLOWLY TO
THE SOUTHWEST TOWARDS THE METROPLEX. WITH MODEST INSTABILITY
PRESENT...A FEW STORMS WILL BE STRONG WITH BRIEF HEAVY RAIN AND
SMALL HAIL. STORM MOTION IS VERY SLOW GIVEN WEAK MID LEVEL
FLOW...WITH MOVEMENT GENERALLY TO THE SOUTHEAST LESS THAT 10 MPH.
ACTIVITY SHOULD LINGER INTO THE EARLY EVENING HOURS AND GRADUALLY
DIMINISH AS SURFACE HEATING WANES AND SUBSIDENCE FROM THE UPPER
RIDGE TAKES HOLD. WILL DECREASE THE CHANCE POPS TO SLIGHT CHANCE
AFTER 7 PM FOR AREAS CURRENTLY AFFECTED BY FRONTAL ACTIVITY.
NEXT...WILL BE WATCHING A SHORTWAVE VAGUELY SHOWING UP OVER NEW
MEXICO ON THE WATER VAPOR SATELLITE. MODELS DEPICT THIS FEATURE
ROTATING EAST AROUND THE 500 MB RIDGE AND ENHANCING ACTIVITY
CURRENTLY DEVELOPING OVER NORTHWEST TEXAS. FEEL THIS ACTIVITY HAS
THE POTENTIAL TO BECOME ORGANIZED AND APPROACH THE AREA FROM THE
NORTHWEST TONIGHT...ESPECIALLY GIVEN THE PRESENCE OF THE SURFACE
BOUNDARY AND ASSOCIATED AXIS OF MOISTURE AND INSTABILITY TO WORK
WITH. NAM MAY ONCE AGAIN BE TOO AGGRESSIVE WITH MCS/COLD POOL
DEVELOPMENT...AND SUBSEQUENT SOLUTION OF WIDESPREAD PRECIP NORTH
OF I 20 AFTER MIDNIGHT TONIGHT. NEVERTHELESS IT CANNOT BE
COMPLETELY IGNORED...AND WILL INCLUDE CHANCE POPS OVER THE
NORTHWESTERN COUNTIES FOR THE OVERNIGHT HOURS...WITH SLIGHT CHANCE
FURTHER SOUTHEAST INCLUDING THE DALLAS FORT WORTH METROPLEX.
THE UPPER RIDGE WILL CONTINUE TO SHIFT SLOWLY EAST OVER THE NEXT
COUPLE OF DAYS. FLOW WILL TRANSITION TO SOUTHWESTERLY AT THE MID
AND UPPER LEVELS AS A LONGWAVE TROUGH DEVELOPS OVER THE WESTERN
CONUS. LOW-END POPS WILL BE POSSIBLE AS WE APPROACH THE WEEKEND
DUE MAINLY TO WARM ADVECTION SHOWERS. THIS WILL CHANGE ABRUPTLY
INTO WIDESPREAD CONVECTION LATE IN THE WEEKEND AS THE UPPER TROUGH
OVERSPREADS THE REGION...ACCOMPANIED BY A PACIFIC COLD FRONT.
AS WITH ANY PROGRESSIVE SYNOPTIC SCALE TROUGH DURING THE SPRING
MONTHS...LOCALLY HEAVY RAIN AND SEVERE WEATHER COULD BOTH BE A
GOOD POSSIBILITY AS THE SYSTEM SWINGS THROUGH THE REGION. COOLER
DRIER AIR IS THEN EXPECTED BY TUESDAY OF NEXT WEEK AS THE UPPER
LEVEL SYSTEM HEADS FOR THE EAST COAST AND THE FRONT MOVES EAST OF
THE STATE.
30
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 61 78 64 79 64 / 10 10 10 10 10
WACO, TX 63 79 64 78 64 / 10 10 10 10 10
PARIS, TX 53 73 60 76 60 / 10 20 10 10 10
DENTON, TX 58 77 64 77 63 / 10 20 10 10 10
MCKINNEY, TX 56 75 63 75 62 / 10 20 10 10 10
DALLAS, TX 62 78 64 78 64 / 10 10 10 10 10
TERRELL, TX 58 76 62 78 61 / 10 10 10 10 10
CORSICANA, TX 61 78 62 79 61 / 10 10 10 10 10
TEMPLE, TX 63 79 63 79 65 / 10 10 10 10 10
MINERAL WELLS, TX 61 78 62 78 64 / 20 20 10 20 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS CARIBOU ME
912 AM EDT THU APR 12 2012
.SYNOPSIS...
SECONDARY LOW PRESSURE SOUTHEAST OF NOVA SCOTIA WILL SLOWLY
TRACK EAST INTO THE OPEN ATLANTIC BY EVENING. HIGH PRESSURE WILL
GRADUALLY BUILD EAST TONIGHT THROUGH FRIDAY. A WARM FRONT WILL
APPROACH FROM THE WEST SATURDAY AND CROSS THE REGION SATURDAY
NIGHT... FOLLOWED BY A COLD FRONT FROM CENTRAL CANADA SUNDAY
NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE: A LINE OF SHOWERS PERSISTS FROM JUST SOUTH OF PRESQUE ISLE
SOUTH SOUTHWEST TOWARD PATTEN AND SHERMAN SO HAVE UPDATED FORECAST
TO GO NUMEROUS SHOWERS IN THIS CORRIDOR.
OTHERWISE...WE MODIFIED FCST LOWS BASED ON LATEST 10Z OBSVD SFC
TEMPS...WITH MOST OF THIS OCCURRING OVR ERN PTNS OF THE FA DUE TO
WARMER THAN ANTICIPATED OBS COMPARED TO FCST LOWS COMPARED TO THIS
PTN OF THE FCST AREA. WRN VLYS DID COOL TO MID TO UPPER 20S...SO
VIRTUALLY NO CHG WAS MADE TO LOW TEMPS THERE. BY MAKING THESE LATE
ADJUSTMENTS...WE ARE ABLE TO MERGE TO FCST HI TEMPS THIS AFTN AND
PRODUCE A MORE REALISTIC RISING TEMP CURVE FOR THIS MORN.
ORGNL DISC: MOST MODELS INDICATE LITTLE IF ANY SHWRS TO AFFECT
OUR FA TDY...YET LATEST RADAR REF IMAGERY SHOWS ISOLD-SCT SHWRS
OVR E CNTRL AND DOWNEAST PTNS OF THE FA...WITH MORE INTENSE AND
GREATER CVRG OF SHWRS JUST OVR THE BORDER IN NB PROV. HRRR FCST
REF SHOWS THE MORE INTENSE SHWRS WEAKENING BEFORE CROSSING WWRD
INTO E CNTRL AND SE ME THIS MORN...BUT SHOWS ADDITIONAL RN SHWRS
DEVELOPING OVR E CNTRL AND DOWNEAST PTNS OF THE FA THIS AFTN DUE
TO DESTABILIZATION OF THE LOWER ATMOSPHERE UNDER THE EXITING UPPER
LVL LOW. WITH THIS IN MIND...WE BROUGHT SCT SHWRS FURTHER N THIS
MORN INTO ERLY AFTN THAN PREVIOUS UPDATES. FCST LOW VALUES OF
6HRLY QPF THRU THIS EVE WAS BASED ON INCREMENTAL INTERVALS OF POP
VALUES...AND IS RATHER A POTENTIAL OF QPF WITH INDIVIDUAL SHWRS
OVR PARTICULAR LOCATIONS RATHER THAN AN ACTUAL FCST GRADIENT OF
QPF ACROSS THIS PTN OF THE FA.
OTHERWISE...WINDS WILL BE BREEZIER ACROSS THE FA TDY...SPCLY N AND
W WHERE WIND GUSTS UP TO 20 MPH IS XPCTD. HI TEMPS WILL SHOW LESS
N-S GRADIENT THAN TYPICAL THIS TM OF SEASON DUE TO XPCTD GREATER
SUNSHINE POTENTIAL ACROSS THE N BY AFTN. ANY REMAINING SHWRS ERLY
THIS EVE SHOULD DISSIPATE OR MOVE ESE OF DOWNEAST PTNS OF THE FA
BY LATE TNGT. WINDS ACROSS WRN/NRN/CNTRL VLY PTNS OF THE FA COULD
DECOUPLE LATE TNGT UNDER CLRG SKIES...ALLOWING SOME RADIATIONAL
COOLING AND SFC BASED INVSNS RESULTING IN COOLER OVRNGT LOWS OVR
THESE AREAS AS COMPARED TO RECENT PRIOR NGTS
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
HIGH PRESSURE BUILDS FRIDAY WITH A NORTHWESTERLY FLOW. GENERALLY
SUNNY SKIES ARE EXPECTED ACROSS THE FORECAST AREA WITH JUST
SCATTERED THIN CUMULUS AND SOME AFTERNOON CIRRUS. HIGHS SHOULD
REACH THE LOW 50S NORTH AND UPPER 50S DOWN EAST WITH LOW HUMIDITY.
TEMPERATURES WILL CONTINUE TO MODERATE SATURDAY WITH WARM AIR
ADVECTION AND WINDS BACKING TO A MORE WEST TO SOUTHWEST FLOW.
HIGHS WILL REACH THE UPPER 50S NORTH AND LOW 60S DOWN EAST. CLOUDS
WILL INCREASE DURING THE AFTERNOON AS A WEAK WARM FRONT APPROACHES
FROM QUEBEC.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
SOME LIGHT RAIN IS POSSIBLE SATURDAY NIGHT AS A WARM FRONT CROSSES
THE FORECAST AREA. THE FRONT WILL HAVE MOVED OUT OF THE AREA BY
SUNDAY MORNING AND SHOULD SET THE STAGE FOR A WARM AND WINDY DAY
WITH HIGHS REACHING NEAR 60F NORTH AND MID TO UPPER 60S DOWN
EAST...EXCEPT NEAR THE COAST WHERE AN ONSHORE FLOW WILL LIMIT
HIGHS TO THE 50S. SUNSHINE WILL BE SOMEWHAT LIMITED...ESPECIALLY
TOWARDS THE CROWN OF MAINE AS A STRONG COLD FRONT WILL APPROACH
THE THE SJV DURING THE AFTERNOON AND MOVE SOUTH ACROSS THE
FORECAST AREA SUNDAY AFTERNOON AND EVENING. THIS FRONT COULD
PRODUCE SOME LOW-TOPPED CONVECTION BRINGING STRONG GUSTY WINDS TO
THE SURFACE OVER 30 KTS. WITH THE FRONT THROUGH THE AREA...A SUNNY
AND WINDY DAY FOLLOWS FOR MONDAY. THE BIGGEST QUESTION WILL BE THE
EXTENT OF THE COLD AIR ADVECTION AND STRENGTH OF WINDS. ONE
SCENARIO WOULD PRODUCE HIGHS IN THE LOW 50S NORTH AND ANOTHER DAY
IN THE MID 60S DOWN EAST. THE OTHER END OF THE SPECTRUM ONLY GIVES
HIGHS NEAR 40F IN THE CROWN OF MAINE AND LOW 50S DOWN EAST. AM
FAVORING A BLEND BETWEEN THESE WITH HIGHS IN THE MID 40S NORTH AND
MID 50S DOWN EAST. EITHER WAY...THIS IS A DRY AIR MASS AND
TEMPERATURES SHOULD COOL INTO THE LOW-MID 20S NORTH AND LOW 30S
DOWN EAST ON MONDAY NIGHT.
THE REMAINDER OF THE PERIOD WILL BE CLOUDY...COOL AND WET AS LOW
PRESSURE MOVES SLOWLY FROM THE GREAT LAKES REGION TOWARDS THE NEW
ENGLAND. THE BIGGEST QUESTION WILL BE WHETHER IT WILL BE COLD
ENOUGH TO SUPPORT SNOW IN NORTHERN ZONES TUESDAY MORNING. THIS
WILL DEPEND ON THE AMOUNT OF COLD AIR ADVECTION BEHIND THE COLD
FRONT SUNDAY NIGHT. WILL GO WITH A CHANCE OF SNOW FOR ZONES 1
THROUGH 6 TUESDAY MORNING.
&&
.AVIATION /13Z THURSDAY THROUGH MONDAY/...
NEAR TERM: MAINLY LOW TO MID VFR...WITH A BRIEF PD OF MVFR
POSSIBLE ERLY TO MID MORN...SPCLY DOWNEAST SITES WITH ANY SHWRS.
CLDS SHOULD CLR FROM ALL TAF SITES NW TO SE OVRNGT.
SHORT TERM: VFR. CHANCE OF IFR IN AN AFTERNOON OR EVENING RAIN
SHOWER SUNDAY...ACCOMPANIED BY WEST WINDS GUSTING OVER 30 KTS.
&&
.MARINE...
NEAR TERM: NO HDLNS ANTICIPATED THRU TNGT...WITH NW WINDS OF 10 TO
20 KT DIMINISHING LATE TDY THRU TNGT. WE USED A BLEND OF 00Z NAM12...
GFS40 AND GMOS FOR WINDS AND A 50%/30%/20% WW3/SWAN-NAM/SWAN-GFS
FOR WV HTS.
SHORT TERM: GENERALLY BENIGN CONDITIONS EXCEPT A POSSIBLE SCA
SUNDAY AHEAD OF A COLD FRONT. WAVE HTS OVER 5 FEET ARE MORE LIKELY
TO PRODUCE AN SCA DURING THIS PERIOD RATHER THAN WINDS OVER 25 KTS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MCB
AREA FORECAST DISCUSSION
NWS CARIBOU ME
816 AM EDT THU APR 12 2012
.SYNOPSIS...
SECONDARY LOW PRESSURE SOUTHEAST OF NOVA SCOTIA WILL SLOWLY
TRACK EAST INTO THE OPEN ATLANTIC BY EVENING. HIGH PRESSURE WILL
GRADUALLY BUILD EAST TONIGHT THROUGH FRIDAY. A WARM FRONT WILL
APPROACH FROM THE WEST SATURDAY AND CROSS THE REGION SATURDAY
NIGHT... FOLLOWED BY A COLD FRONT FROM CENTRAL CANADA SUNDAY
NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE: A VERY SLOW MOVING LINE OF SHOWERS EXTENDS FROM THE MAINE
NEW BRUNSWICK BORDER NEAR FORT FAIRFIELD SOUTHWEST ACROSS SOUTHERN
AROOSTOOK COUNTY...SO HAVE PUT SHOWERS INTO THIS AREA THIS
MORNING.
OTHERWISE...WE MODIFIED FCST LOWS BASED ON LATEST 10Z OBSVD SFC
TEMPS...WITH MOST OF THIS OCCURRING OVR ERN PTNS OF THE FA DUE TO
WARMER THAN ANTICIPATED OBS COMPARED TO FCST LOWS COMPARED TO THIS
PTN OF THE FCST AREA. WRN VLYS DID COOL TO MID TO UPPER 20S...SO
VIRTUALLY NO CHG WAS MADE TO LOW TEMPS THERE. BY MAKING THESE LATE
ADJUSTMENTS...WE ARE ABLE TO MERGE TO FCST HI TEMPS THIS AFTN AND
PRODUCE A MORE REALISTIC RISING TEMP CURVE FOR THIS MORN.
ORGNL DISC: MOST MODELS INDICATE LITTLE IF ANY SHWRS TO AFFECT
OUR FA TDY...YET LATEST RADAR REF IMAGERY SHOWS ISOLD-SCT SHWRS
OVR E CNTRL AND DOWNEAST PTNS OF THE FA...WITH MORE INTENSE AND
GREATER CVRG OF SHWRS JUST OVR THE BORDER IN NB PROV. HRRR FCST
REF SHOWS THE MORE INTENSE SHWRS WEAKENING BEFORE CROSSING WWRD
INTO E CNTRL AND SE ME THIS MORN...BUT SHOWS ADDITIONAL RN SHWRS
DEVELOPING OVR E CNTRL AND DOWNEAST PTNS OF THE FA THIS AFTN DUE
TO DESTABILIZATION OF THE LOWER ATMOSPHERE UNDER THE EXITING UPPER
LVL LOW. WITH THIS IN MIND...WE BROUGHT SCT SHWRS FURTHER N THIS
MORN INTO ERLY AFTN THAN PREVIOUS UPDATES. FCST LOW VALUES OF
6HRLY QPF THRU THIS EVE WAS BASED ON INCREMENTAL INTERVALS OF POP
VALUES...AND IS RATHER A POTENTIAL OF QPF WITH INDIVIDUAL SHWRS
OVR PARTICULAR LOCATIONS RATHER THAN AN ACTUAL FCST GRADIENT OF
QPF ACROSS THIS PTN OF THE FA.
OTHERWISE...WINDS WILL BE BREEZIER ACROSS THE FA TDY...SPCLY N AND
W WHERE WIND GUSTS UP TO 20 MPH IS XPCTD. HI TEMPS WILL SHOW LESS
N-S GRADIENT THAN TYPICAL THIS TM OF SEASON DUE TO XPCTD GREATER
SUNSHINE POTENTIAL ACROSS THE N BY AFTN. ANY REMAINING SHWRS ERLY
THIS EVE SHOULD DISSIPATE OR MOVE ESE OF DOWNEAST PTNS OF THE FA
BY LATE TNGT. WINDS ACROSS WRN/NRN/CNTRL VLY PTNS OF THE FA COULD
DECOUPLE LATE TNGT UNDER CLRG SKIES...ALLOWING SOME RADIATIONAL
COOLING AND SFC BASED INVSNS RESULTING IN COOLER OVRNGT LOWS OVR
THESE AREAS AS COMPARED TO RECENT PRIOR NGTS
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
HIGH PRESSURE BUILDS FRIDAY WITH A NORTHWESTERLY FLOW. GENERALLY
SUNNY SKIES ARE EXPECTED ACROSS THE FORECAST AREA WITH JUST
SCATTERED THIN CUMULUS AND SOME AFTERNOON CIRRUS. HIGHS SHOULD
REACH THE LOW 50S NORTH AND UPPER 50S DOWN EAST WITH LOW HUMIDITY.
TEMPERATURES WILL CONTINUE TO MODERATE SATURDAY WITH WARM AIR
ADVECTION AND WINDS BACKING TO A MORE WEST TO SOUTHWEST FLOW.
HIGHS WILL REACH THE UPPER 50S NORTH AND LOW 60S DOWN EAST. CLOUDS
WILL INCREASE DURING THE AFTERNOON AS A WEAK WARM FRONT APPROACHES
FROM QUEBEC.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
SOME LIGHT RAIN IS POSSIBLE SATURDAY NIGHT AS A WARM FRONT CROSSES
THE FORECAST AREA. THE FRONT WILL HAVE MOVED OUT OF THE AREA BY
SUNDAY MORNING AND SHOULD SET THE STAGE FOR A WARM AND WINDY DAY
WITH HIGHS REACHING NEAR 60F NORTH AND MID TO UPPER 60S DOWN
EAST...EXCEPT NEAR THE COAST WHERE AN ONSHORE FLOW WILL LIMIT
HIGHS TO THE 50S. SUNSHINE WILL BE SOMEWHAT LIMITED...ESPECIALLY
TOWARDS THE CROWN OF MAINE AS A STRONG COLD FRONT WILL APPROACH
THE THE SJV DURING THE AFTERNOON AND MOVE SOUTH ACROSS THE
FORECAST AREA SUNDAY AFTERNOON AND EVENING. THIS FRONT COULD
PRODUCE SOME LOW-TOPPED CONVECTION BRINGING STRONG GUSTY WINDS TO
THE SURFACE OVER 30 KTS. WITH THE FRONT THROUGH THE AREA...A SUNNY
AND WINDY DAY FOLLOWS FOR MONDAY. THE BIGGEST QUESTION WILL BE THE
EXTENT OF THE COLD AIR ADVECTION AND STRENGTH OF WINDS. ONE
SCENARIO WOULD PRODUCE HIGHS IN THE LOW 50S NORTH AND ANOTHER DAY
IN THE MID 60S DOWN EAST. THE OTHER END OF THE SPECTRUM ONLY GIVES
HIGHS NEAR 40F IN THE CROWN OF MAINE AND LOW 50S DOWN EAST. AM
FAVORING A BLEND BETWEEN THESE WITH HIGHS IN THE MID 40S NORTH AND
MID 50S DOWN EAST. EITHER WAY...THIS IS A DRY AIR MASS AND
TEMPERATURES SHOULD COOL INTO THE LOW-MID 20S NORTH AND LOW 30S
DOWN EAST ON MONDAY NIGHT.
THE REMAINDER OF THE PERIOD WILL BE CLOUDY...COOL AND WET AS LOW
PRESSURE MOVES SLOWLY FROM THE GREAT LAKES REGION TOWARDS THE NEW
ENGLAND. THE BIGGEST QUESTION WILL BE WHETHER IT WILL BE COLD
ENOUGH TO SUPPORT SNOW IN NORTHERN ZONES TUESDAY MORNING. THIS
WILL DEPEND ON THE AMOUNT OF COLD AIR ADVECTION BEHIND THE COLD
FRONT SUNDAY NIGHT. WILL GO WITH A CHANCE OF SNOW FOR ZONES 1
THROUGH 6 TUESDAY MORNING.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
NEAR TERM: MAINLY LOW TO MID VFR...WITH A BRIEF PD OF MVFR
POSSIBLE ERLY TO MID MORN...SPCLY DOWNEAST SITES WITH ANY SHWRS.
CLDS SHOULD CLR FROM ALL TAF SITES NW TO SE OVRNGT.
SHORT TERM: VFR. CHANCE OF IFR IN AN AFTERNOON OR EVENING RAIN
SHOWER SUNDAY...ACCOMPANIED BY WEST WINDS GUSTING OVER 30 KTS.
&&
.MARINE...
NEAR TERM: NO HDLNS ANTICIPATED THRU TNGT...WITH NW WINDS OF 10 TO
20 KT DIMINISHING LATE TDY THRU TNGT. WE USED A BLEND OF 00Z NAM12...
GFS40 AND GMOS FOR WINDS AND A 50%/30%/20% WW3/SWAN-NAM/SWAN-GFS
FOR WV HTS.
SHORT TERM: GENERALLY BENIGN CONDITIONS EXCEPT A POSSIBLE SCA
SUNDAY AHEAD OF A COLD FRONT. WAVE HTS OVER 5 FEET ARE MORE LIKELY
TO PRODUCE AN SCA DURING THIS PERIOD RATHER THAN WINDS OVER 25 KTS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MCB
AREA FORECAST DISCUSSION
NWS CARIBOU ME
635 AM EDT THU APR 12 2012
.SYNOPSIS...
SECONDARY LOW PRESSURE SOUTHEAST OF NOVA SCOTIA WILL SLOWLY
TRACK EAST INTO THE OPEN ATLANTIC BY EVENING. HIGH PRESSURE WILL
GRADUALLY BUILD EAST TONIGHT THROUGH FRIDAY. A WARM FRONT WILL
APPROACH FROM THE WEST SATURDAY AND CROSS THE REGION SATURDAY
NIGHT... FOLLOWED BY A COLD FRONT FROM CENTRAL CANADA SUNDAY
NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE 1: WITH THE HRRR MODEL CONTG TO SHOW MORE RNFL ECHOES FCST
CROSS INTO SE ME FROM SRN/CNTRL NB PROV AND RADAR OBS BACKING THIS
MODEL...WE OPTD TO INCREASE POPS TO LIKELY CAT ACROSS SE ME AND
ALG THE DOWNEAST COAST OF HANCOCK COUNTY FOR THIS MORN INTO ERLY
AFTN WITH A MODEST INCREASE IN 12-18Z AND 18-24Z 6HRLY QPF GRIDS
OVR THESE PTNS OF THE FA. AGAIN...FCST QPF OVR THESE AREAS REFLECTS
A POTENTIAL OF QPF WITH INDIVIDUAL MORE INTENSE SHWRS OVR THIS
AREA RATHER THAN AN ACTUAL FCST OF QPF GRADIENT.
OTHERWISE...WE MODIFIED FCST LOWS BASED ON LATEST 10Z OBSVD SFC
TEMPS...WITH MOST OF THIS OCCURRING OVR ERN PTNS OF THE FA DUE TO
WARMER THAN ANTICIPATED OBS COMPARED TO FCST LOWS COMPARED TO THIS
PTN OF THE FCST AREA. WRN VLYS DID COOL TO MID TO UPPER 20S...SO
VIRTUALLY NO CHG WAS MADE TO LOW TEMPS THERE. BY MAKING THESE LATE
ADJUSTMENTS...WE ARE ABLE TO MERGE TO FCST HI TEMPS THIS AFTN AND
PRODUCE A MORE REALISTIC RISING TEMP CURVE FOR THIS MORN.
ORGNL DISC: MOST MODELS INDICATE LITTLE IF ANY SHWRS TO AFFECT
OUR FA TDY...YET LATEST RADAR REF IMAGERY SHOWS ISOLD-SCT SHWRS
OVR E CNTRL AND DOWNEAST PTNS OF THE FA...WITH MORE INTENSE AND
GREATER CVRG OF SHWRS JUST OVR THE BORDER IN NB PROV. HRRR FCST
REF SHOWS THE MORE INTENSE SHWRS WEAKENING BEFORE CROSSING WWRD
INTO E CNTRL AND SE ME THIS MORN...BUT SHOWS ADDITIONAL RN SHWRS
DEVELOPING OVR E CNTRL AND DOWNEAST PTNS OF THE FA THIS AFTN DUE
TO DESTABILIZATION OF THE LOWER ATMOSPHERE UNDER THE EXITING UPPER
LVL LOW. WITH THIS IN MIND...WE BROUGHT SCT SHWRS FURTHER N THIS
MORN INTO ERLY AFTN THAN PREVIOUS UPDATES. FCST LOW VALUES OF
6HRLY QPF THRU THIS EVE WAS BASED ON INCREMENTAL INTERVALS OF POP
VALUES...AND IS RATHER A POTENTIAL OF QPF WITH INDIVIDUAL SHWRS
OVR PARTICULAR LOCATIONS RATHER THAN AN ACTUAL FCST GRADIENT OF
QPF ACROSS THIS PTN OF THE FA.
OTHERWISE...WINDS WILL BE BREEZIER ACROSS THE FA TDY...SPCLY N AND
W WHERE WIND GUSTS UP TO 20 MPH IS XPCTD. HI TEMPS WILL SHOW LESS
N-S GRADIENT THAN TYPICAL THIS TM OF SEASON DUE TO XPCTD GREATER
SUNSHINE POTENTIAL ACROSS THE N BY AFTN. ANY REMAINING SHWRS ERLY
THIS EVE SHOULD DISSIPATE OR MOVE ESE OF DOWNEAST PTNS OF THE FA
BY LATE TNGT. WINDS ACROSS WRN/NRN/CNTRL VLY PTNS OF THE FA COULD
DECOUPLE LATE TNGT UNDER CLRG SKIES...ALLOWING SOME RADIATIONAL
COOLING AND SFC BASED INVSNS RESULTING IN COOLER OVRNGT LOWS OVR
THESE AREAS AS COMPARED TO RECENT PRIOR NGTS
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
HIGH PRESSURE BUILDS FRIDAY WITH A NORTHWESTERLY FLOW. GENERALLY
SUNNY SKIES ARE EXPECTED ACROSS THE FORECAST AREA WITH JUST
SCATTERED THIN CUMULUS AND SOME AFTERNOON CIRRUS. HIGHS SHOULD
REACH THE LOW 50S NORTH AND UPPER 50S DOWN EAST WITH LOW HUMIDITY.
TEMPERATURES WILL CONTINUE TO MODERATE SATURDAY WITH WARM AIR
ADVECTION AND WINDS BACKING TO A MORE WEST TO SOUTHWEST FLOW.
HIGHS WILL REACH THE UPPER 50S NORTH AND LOW 60S DOWN EAST. CLOUDS
WILL INCREASE DURING THE AFTERNOON AS A WEAK WARM FRONT APPROACHES
FROM QUEBEC.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
SOME LIGHT RAIN IS POSSIBLE SATURDAY NIGHT AS A WARM FRONT CROSSES
THE FORECAST AREA. THE FRONT WILL HAVE MOVED OUT OF THE AREA BY
SUNDAY MORNING AND SHOULD SET THE STAGE FOR A WARM AND WINDY DAY
WITH HIGHS REACHING NEAR 60F NORTH AND MID TO UPPER 60S DOWN
EAST...EXCEPT NEAR THE COAST WHERE AN ONSHORE FLOW WILL LIMIT
HIGHS TO THE 50S. SUNSHINE WILL BE SOMEWHAT LIMITED...ESPECIALLY
TOWARDS THE CROWN OF MAINE AS A STRONG COLD FRONT WILL APPROACH
THE THE SJV DURING THE AFTERNOON AND MOVE SOUTH ACROSS THE
FORECAST AREA SUNDAY AFTERNOON AND EVENING. THIS FRONT COULD
PRODUCE SOME LOW-TOPPED CONVECTION BRINGING STRONG GUSTY WINDS TO
THE SURFACE OVER 30 KTS. WITH THE FRONT THROUGH THE AREA...A SUNNY
AND WINDY DAY FOLLOWS FOR MONDAY. THE BIGGEST QUESTION WILL BE THE
EXTENT OF THE COLD AIR ADVECTION AND STRENGTH OF WINDS. ONE
SCENARIO WOULD PRODUCE HIGHS IN THE LOW 50S NORTH AND ANOTHER DAY
IN THE MID 60S DOWN EAST. THE OTHER END OF THE SPECTRUM ONLY GIVES
HIGHS NEAR 40F IN THE CROWN OF MAINE AND LOW 50S DOWN EAST. AM
FAVORING A BLEND BETWEEN THESE WITH HIGHS IN THE MID 40S NORTH AND
MID 50S DOWN EAST. EITHER WAY...THIS IS A DRY AIR MASS AND
TEMPERATURES SHOULD COOL INTO THE LOW-MID 20S NORTH AND LOW 30S
DOWN EAST ON MONDAY NIGHT.
THE REMAINDER OF THE PERIOD WILL BE CLOUDY...COOL AND WET AS LOW
PRESSURE MOVES SLOWLY FROM THE GREAT LAKES REGION TOWARDS THE NEW
ENGLAND. THE BIGGEST QUESTION WILL BE WHETHER IT WILL BE COLD
ENOUGH TO SUPPORT SNOW IN NORTHERN ZONES TUESDAY MORNING. THIS
WILL DEPEND ON THE AMOUNT OF COLD AIR ADVECTION BEHIND THE COLD
FRONT SUNDAY NIGHT. WILL GO WITH A CHANCE OF SNOW FOR ZONES 1
THROUGH 6 TUESDAY MORNING.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
NEAR TERM: MAINLY LOW TO MID VFR...WITH A BRIEF PD OF MVFR
POSSIBLE ERLY TO MID MORN...SPCLY DOWNEAST SITES WITH ANY SHWRS.
CLDS SHOULD CLR FROM ALL TAF SITES NW TO SE OVRNGT.
SHORT TERM: VFR. CHANCE OF IFR IN AN AFTERNOON OR EVENING RAIN
SHOWER SUNDAY...ACCOMPANIED BY WEST WINDS GUSTING OVER 30 KTS.
&&
.MARINE...
NEAR TERM: NO HDLNS ANTICIPATED THRU TNGT...WITH NW WINDS OF 10 TO
20 KT DIMINISHING LATE TDY THRU TNGT. WE USED A BLEND OF 00Z NAM12...
GFS40 AND GMOS FOR WINDS AND A 50%/30%/20% WW3/SWAN-NAM/SWAN-GFS
FOR WV HTS.
SHORT TERM: GENERALLY BENIGN CONDITIONS EXCEPT A POSSIBLE SCA
SUNDAY AHEAD OF A COLD FRONT. WAVE HTS OVER 5 FEET ARE MORE LIKELY
TO PRODUCE AN SCA DURING THIS PERIOD RATHER THAN WINDS OVER 25 KTS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...VJN
SHORT TERM...MCW
LONG TERM...MCW
AVIATION...VJN
MARINE...VJN/MCW
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
739 AM EDT THU APR 12 2012
.SYNOPSIS...
ISSUED AT 426 AM EDT THU APR 12 2012
WV IMAGERY AND RUC ANALYSIS INDICATED AN AMPLIFIED PATTERN WITH A
MID/UPPER LEVEL TROUGH INTO THE WRN CONUS A RIDGE OVER THE PLAINS
AND A TROUGH OVER THE EAST RESULTING IN NW FLOW THROUGH THE NRN
GREAT LAKES. A WELL-DEFINED UPSTREAM SHORTWAVE TROUGH WAS LOCATED
OVER NRN ONTARIO NEAR CYPL. AT THE SFC...A RIDGE EXTENDED FROM JAMES
BAY THROUGH THE WRN GREAT LAKES LEAVING CLEAR SKIES...LIGHT WINDS
OVER UPPER MI AND SEASONABLY COOL TEMPS IN THE DRY AIRMASS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 426 AM EDT THU APR 12 2012
TODAY...SINCE A VERY DRY AIRMASS DOMINATED THE REGION...PER 00Z
CYPL/KAPX/KGRB SOUNDINGS ONLY MID/HIGH CLOUDS WERE ASSOCIATED WITH
THE NRN ONTARIO SHRTWV. SIMILARLY...AS THE SHRTWV MOVES THROUGH LAKE
SUPERIOR AND ERN UPPER MI...ONLY MID CLOUDS ARE EXPECTED DESPITE
MODERATE 700-300 MB QVECTOR CONV. WITH A DECENT AMOUNT OF
SUNSHINE...TEMPS SHOULD CLIMB INTO THE MID AND UPPER 50S INLAND
WEST. THE WEAK PRESSURE GRADIENT WILL ALLOW LAKE BREEZES TO
DEVELOP...KEEPING READINGS AOB 50 ALONG THE GREAT LAKES. AFTERNOON
MIXING SHOULD ALSO DROP DEWPOINTS TO AROUND 20 WITH RH AOB 25 PCT
INLAND WEST.
TONIGHT...TEMPS WILL AGAIN DROP BELOW FREEZING IN MOST LOCATIONS AS
LIGHT WINDS PREVAIL AND HIGH CLOUDS ONLY MOVE INTO THE WEST LATE.
SLIGHTLY HIGHER TEMPS ARE EXPECTED WITH DOWNSLOPE SE FLOW WEST NEAR
LAKE SUPERIOR.
FRIDAY INTO FRIDAY NIGHT...MODELS SUGGEST THAT THE TROUGH WILL
ADVANCE TO THE EAST AS A SHORTWAVE LIFTS NE FROM THE PLAINS THROUGH
MN INTO NRN ONTARIO AND THE NRN LAKES. A BAND OF WAA/ISENTROPIC LIFT
ALONG WITH FAVORABLE MOISTURE TRANSPORT SHOULD PRODUCE SCT/NMRS
SHRA MOVING INTO THE WEST LATE FRIDAY AND ACROSS THE CWA FRIDAY
NIGHT. THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE TIMING OF
PCPN MOVING INTO THE AREA. SINCE THE DYNAMICS MOVE THROUGH FAIRLY
QUICKLY...ONLY MODEST PCPN AMOUNTS IN THE 0.10-0.20 INCH RANGE ARE
EXPECTED. WITH ELEVATED CAPE REMAINING SOUTH OF THE AREA...PER
NAM/GFS...NO TSRA ARE EXPECTED.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 426 AM EDT THU APR 12 2012
H925-700 WAA AHEAD OF THE WARM FRONT WILL BE PUSHING NE ACROSS NE
LAKE SUPERIOR AT THE START OF THE PERIOD...WHILE DRY SLOT WORKS OVER
THE REST OF THE CWA DURING THE MORNING HOURS. LLVL MOISTURE LINGERS
IN THE MORNING AND QUICKLY DIMINISHES IN THE AFTN...SO HAVE LOWERED
TO PARTLY CLOUDY IN THE AFTN AHEAD OF NEXT WAVE AND APPROACHING COLD
FRONT FROM THE NW ON SAT NIGHT. AS A RESULT...HAVE DIMINISHED POPS
FROM W TO E DURING THE MORNING HRS AND REMOVED THEM COMPLETELY FOR
THE AFTN. COULD END UP BEING A WARM DAY ON SAT. MIXING TO H925-900
WITH THE DECREASING CLOUDS AND SSW WINDS WOULD LEAD TO HIGHS IN THE
60S TO LOWER 70S. LIKE THE PREVIOUS SHIFT...MADE ANOTHER JUMP IN THE
TEMPS /3-7 DEGREES/ FOR SAT OVER THE WRN TWO THIRDS. THIS COULD EVEN
BE A FEW DEGREES TOO LOW IF THE CLOUDS REALLY CLEAR OUT IN THE AFTN
AND THE WINDS ARE STRONG ENOUGH TO LIMIT LK BREEZES NEAR LK
SUPERIOR.
COLD FRONT ASSOCIATED WITH THE LOW THAT PUSHED THROUGH ONTARIO ON
SAT WILL MOVE SE ACROSS UPPER MI ON SAT NIGHT. THE TIMING OF THIS
FRONT AND A SHORTWAVE/LOW MOVING UP FRONT WILL DETERMINE PCPN
CHANCES FOR SAT NIGHT. WITH THE WAY THE MODELS HAVE BEEN FOR THIS
UPCOMING WEEKEND...LIMITED CONFIDENCE ON PCPN CHANCES BUT CHANCES
OVER THE SRN HALF OF THE CWA SEEM REASONABLE AT THIS POINT. THIS
FRONT SHOULD SLIDE FARTHER SE AND CONTINUE TO DIMINISH PCPN CHANCES
ON SUN.
UNCERTAINTY CONTINUES FARTHER OUT INTO THE FORECAST WITH THE SW FLOW
ALOFT FROM THE UPPER TROUGH OVER THE WRN CONUS. MODELS TRADITIONALLY
HAVE A DIFFICULT TIMING WITH THESE SITUATIONS DUE TO SHORTWAVES OVER
THE PACIFIC HAVING TO ROTATE THROUGH THE UPPER TROUGH AND THE LAST
COUPLE OF DAYS OF RUNS HAVE BEEN NO DIFFERENT.
00Z GEM/GFS/ECMWF COMING INTO BETTER AGREEMENT WITH A LOW PUSHING
OUT OF THE CNTRL/SRN PLAINS ON SUN NIGHT AND INTO THE LOWER GREAT
LKS ON MON AFTN/NIGHT. STILL DIFFERENCES ON THE TIMING/TRACK...BUT
STARTING TO GET A BETTER FEEL ON THIS SYSTEM. THIS WOULD BRING AN
INITIAL SURGE OF WAA PCPN TO THE AREA LATE SUN NIGHT AND INTO MON
/24HRS EARLIER THAN YESTERDAY/...BEFORE THE PCPN REFOCUSES FARTHER
SE AND CLOSER TO THE LOW AND UPPER ENERGY. COLD AIR BEHIND THE COLD
FRONT ON SAT NIGHT AND SUN WILL LEAVE A COLD NEAR SFC LAYER.
ALOFT...HINTS AT A NOSE OF 1C TEMPS BETWEEN H850-700 BUT LIKELY
WON/T BE ENOUGH TO ENTIRELY MELT THE SNOW. WITH THE UNCERTAINTY IN
THE MODELS...FOLLOWED THE MODEL CONSENSUS ON THE 1000-850/850-700
THICKNESS PATTERN AND USED THAT FOR PCPN TYPE. THIS PRODUCES A
RAIN/SNOW MIX WHERE THAT WARM AIR NOSE IS OVER THE FAR SE PART OF
THE CWA AND SNOW ELSEWHERE. MODEL QPF SHOWS THE POTENTIAL FOR
MEASURABLE/ADVISORY SNOW OVER THE WRN CWA ON MON...SO WILL BE
INTERESTING IF THAT CONTINUES ON FUTURE RUNS.
00Z GFS/GEM HOLDING ON TO THE PCPN OVER THE SE HALF OF THE CWA ON
TUES...AS ISENTROPIC ASCENT CONTINUES AROUND THE H850 LOW CENTERED
OVER NRN LK MI. 12Z ECMWF HAS ALREADY MOVED THE HIGH PRESSURE RIDGE
IN BY THIS TIME...SO WILL CONTINUE TO MENTION CHANCES MAINLY OVER
THE SE HALF OF THE CWA. THEN WILL SHOW A DIMINISHING TREND IN PCPN
ON TUES NIGHT AND WED. RIGHT NOW...00Z GFS SHOWING HIGH PRESSURE
RIDGE MOVING OVER THE AREA AT THAT TIME. 12Z ECMWF IS FASTER WITH AN
APPROACHING COLD FRONT AND MOVES IT THROUGH ON WED MORNING BUT THE
00Z RUN BACKED OFF ON THAT POTENTIAL. WILL GO WITH A MAINLY DRY
FORECAST FOR WED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 738 AM EDT THU APR 12 2012
PATCHY EARLY MORNING RADIATION FOG AND LOW CLOUDS AT CMX AND SAW
SHOULD DISSIPATE QUICKLY THIS MORNING ONCE MIXING GETS UNDERWAY A
FEW HOURS AFTER SUNRISE. WITH HIGH PRESSURE DOMINATING...VFR
CONDITIONS WILL PERSIST THROUGH THE REST OF THE FCST PD.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 426 AM EDT THU APR 12 2012
HIGH PRESSURE WILL COVER THE UPPER GREAT LAKES REGION TODAY AND
TONIGHT...LEADING TO WINDS BELOW 20KTS. A LOW PRESSURE SYSTEM
TAKING SHAPE OVER THE GREAT PLAINS WILL MOVE NORTHEAST ON FRIDAY
AND INTO ONTARIO ON SAT. WINDS WILL SHIFT TO THE SE...BUT THE
MARINE LAYER SHOULD KEEP WINDS FROM EXCEEDING 20KTS. THIS MARINE
LAYER WILL REMAIN IN PLACE UNTIL A COLD FRONT MOVES THROUGH ON
SATURDAY NIGHT. THIS WILL SHIFT THE WINDS TO THE NW UP TO 25KTS ON
SUN.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...SRF
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
957 AM CDT THU APR 12 2012
.DISCUSSION.../ISSUED AT 957 AM CDT/
MAIN UPDATES TO THE FORECAST WERE TO BRING SCATTERED SHOWERS AND
THUNDERSTORMS INTO THE EASTERN HALF OF THE REGION A BIT EARLIER
THIS MORNING...AND TO LOWER AFTERNOON CHANCES A BIT AS SHOWERS
LOOK TO BE WIDELY SCATTERED. MODELS DO NOT HAVE A GOOD HANDLE ON
THIS AFTERNOON...WITH THE HRRR BROAD BRUSHING THE ENTIRE AREA WITH
PRECIPITATION UNTIL 00Z...AND OTHER MODELS NOT CAPTURING CURRENT
RAINFALL AND HOLDING OFF WITH ANY ACCUMULATION UNTIL THIS EVENING.
CURRENTLY...FEEL AS THOUGH THERE WILL BE A BREAK STARTING IN THE
EARLY AFTERNOON AFTER THE MIDLEVEL WAVE MOVES THROUGH...THEN HEAVIER
PRECIPITATION STARTING UP AHEAD OF THE FRONT THIS EVENING. WILL PLAN
TO KEEP AN EYE ON PRECIPITATION TRENDS TO THE SOUTHWEST AND FUTURE
HRRR RUNS IF THEY BECOME AVAILABLE...AND WILL CONTINUE TO UPDATE
THIS MORNING AS NEEDED. /LAFLIN
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
STRATUS WILL CONTINUE TO INVADE FROM THE SOUTHWEST...ALTHOUGH MOST
OF THE DAY IT WILL REMAIN AT A LOW END VFR. SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS WILL BE POSSIBLE THROUGH THE MORNING IN THE
WESTERN PART OF THE CWA WHILE THE EASTERN PART OF THE CWA WILL HAVE
THE BETTER CHANCES IN THE EARLY AFTERNOON. A MORE ORGANIZED AREA OF
RAIN AND THUNDERSTORMS WILL BE LIKELY TONIGHT WITH MVFR CEILINGS AND
SPOTTY MVFR VISIBILITIES. /08
&&
.PREV DISCUSSION.../ISSUED AT 455 AM CDT/
ABOUT AS COMPLEX A FORECAST AS CAN GET THIS MORNING...WITH
EVERYTHING FROM FIRE WEATHER...TO RAIN TIMING OVER A 5 DAY PERIOD...
SEVERE WEATHER...AND EVEN SNOW TO CONSIDER. SPRING IN ITS FINEST
FORM.
RIDGE ACROSS PLAINS STARTS TO BREAK DOWN TODAY AS ENERGY RIDES UP
THE ROCKIES SIDE. LEADING WAVE IS SHEARING NORTHWARD FROM SOUTHERN
WYOMING TO EASTERN COLORADO...AND RECENTLY HAS AIDED IN DEVELOPMENT
OF SHOWERS AND THUNDERSTORMS ACROSS WESTERN AND SOUTHWESTERN
NEBRASKA. MOISTURE RETURN IS TAKING THE LONG WAY AROUND...THROUGH
THE WESTERN PLAINS WITH THIS SYSTEM...WITH DEEP DRY LAYER TO
DISPLACE IN THE EAST AS THE LOW LEVEL JET SHIFTS GRADUALLY EASTWARD
THROUGH THE DAY. NOT OVERLY IMPRESSED WITH THE LEADING SYSTEM
TODAY...AND STILL FEEL AS IF POPS MAY APPEAR TO BE OVERDONE.
EVOLUTION EXPECTED TO FIND A BAND OF SCATTERED TO BROKEN LIGHT
SHOWERS PUSHING EAST/NORTHEAST ACROSS THE CWA. NOTHING OUT THERE
YET...BUT INCREASE IN 850-700 THETA E ADVECTION SHOULD HELP TO
GENERATE SOME SHRA BY DAYBREAK IN THE WESTERN THIRD. EASTWARD
MOVEMENT WILL BE SOMEWHAT DIFFICULT WITH DRIER AIRMASS AT LOWER
LEVELS...BUT WITH SOME INSTABILITY ROOTED AT 800-750 HPA...SHOWERY
PRECIP SHOULD INCREASINGLY THREATEN TO REACH THE GROUND...AND WHILE
FAIRLY UNLIKELY...COULD SEE A REMOTE RUMBLE OR TWO WITHIN THE BAND.
COVERAGE MAY MAX OUT AROUND MIDDAY OR EARLY AFTERNOON...WITH ENTIRE
ZONE WEAKENING THROUGH LATER AFTERNOON PUSHING EASTWARD INTO
SOUTHWEST MINNESOTA.
MUCH MORE IMPRESSED BY THE SYSTEM ROUNDING THE BASE OF THE TROUGH IN
NW ARIZONA...WHICH WILL LIFT THROUGH THE WESTERN PLAINS TONIGHT.
STRONGER MID LEVEL WAVE LIFTING NORTHEAST ALONG WITH DEEP LOWER
LEVEL MOISTURE TRANSPORT SHOULD FOCUS A MORE IMPRESSIVE COVERAGE OF
SHOWERS LIFTING NORTHEAST ACROSS THE CWA DURING THE OVERNIGHT.
INSTABILITY ON THE NOSE OF MID LEVEL DRYING WILL LIKELY HAVE SOME
BETTER THUNDER COVERAGE AS WELL. PRECIPITATION WILL CONTINUE NORTH
AND EAST EARLY IN THE DAY...AND THEN MAY FIND A LARGELY QUIET PERIOD.
LOW LEVEL JET VEERING EAST...AND WITH JET DRIVING FLOW MORE
SOUTHWEST...SHOULD ERODE THE LINGERING LOW LEVEL MOISTURE FROM WEST
TO EAST. IN FACT...WILL YIELD A FAIRLY MIXY DAY FOR THE AREA WHICH
CLEARS...WITH TEMPERATURES INTO THE UPPER 60S TO LOWER 70S...WHILE
CLOUDS SHROUDING THE FAR EAST COULD KEEP READINGS CLOSER TO 60. FIRE
DANGER FOR THE MOMENT CAME OUT HIGH...BUT IF DEWPOINTS CAN COLLAPSE
AND WINDS UP A BIT MORE...WOULD NOT BE SURPRISED TO FIND VERY HIGH
FIRE DANGER ALONG AND SOUTH OF INTERSTATE 90 IN SOUTHEAST SOUTH
DAKOTA...IN WARMER WEDGE BETWEEN APPROACHING FRONT AND THE MOIST
AXIS TO THE EAST.
NOT MUCH OF ANY APPRECIABLE CONVERGENCE ALONG THE COLD FRONT
APPROACHING FROM THE NORTHWEST...BUT KEPT JUST A VERY LOW END POP
AGAIN BY LATER AFTERNOON IN THE NORTH. ELSEWHERE...ANOTHER
DISTURBANCE RIDING QUICKLY IN FROM THE SOUTHWEST MAY IMPACT SOME
DEVELOPMENT NEAR THE RETREATING WARM FRONT ACROSS NORTHWEST IOWA
DURING THE LATER AFTERNOON...AND MAY HAVE TO WATCH FOR AN ISOLATED
MARGINALLY SEVERE STORM GIVEN THE LONG HODOGRAPH AND UP TO 750 J/KG
WEAKLY CAPPED INSTABILITY.
SURFACE FRONT WILL CONTINUE TO SLOWLY DROP SOUTHWARD THROUGH
SATURDAY...THEN WILL LIKELY STALL IN EASTERN NEBRASKA AS
LOW LEVEL FLOW BACKS AND GET COMBINATION OF ENHANCE WARM AIR
ADVECTION/MID LEVEL DEFORMATION FOCUSING PRECIPITATION FROM LATER
SATURDAY THROUGH SUNDAY NEAR AND NORTH OF THIS BOUNDARY. ONE WAVE
WILL FOCUS A GREATER CHANCE OF SHOWERS/THUNDER ACROSS NORTHWEST IOWA
SATURDAY EVENING BEFORE PEELING EASTWARD. THIS MAY PRESENT A RISK
FOR ISOLATED SEVERE STORMS NEAR THE HIGHWAY 20 CORRIDOR NORTHWARD
TOWARD SPENCER IOWA...WITH DEEP INSTABILITY SOUTH OF THE BOUNDARY
FROM 1500-2000 J/KG...AS WELL AS VERY LONG HODOGRAPHS...AND SHEAR
NICELY FOCUSED DOWN LOW NEAR THE LOCATION OF THE SURFACE BOUNDARY.
BIG CHANGE OVER THE LAST 24 HOURS HAS BEEN EVOLVING CONSENSUS OF
CLOSED OFF SYSTEM LIFTING NORTHEAST INTO THE REGION ON SUNDAY NIGHT
AND MONDAY. QUITE A CONSENSUS DEVELOPING QUICKLY...AND NOW LOOKS TO
BE AT BEST A MIXED PRECIPITATION SYSTEM...AND VERY LIKELY SOME AREAS
WITH ALL SNOWFALL. AT FACE VALUE...WITH 850 HPA TEMPS ON ORDER OF -4
TO -8C ON NORTHWEST FLANK OF SYSTEM BY LATE SUNDAY NIGHT...AND A
CONTINUED THREAT FOR SOME ELEVATED THUNDER INTO NORTHWEST IOWA INTO
SUNDAY NIGHT. STILL SOME WIGGLE ROOM ON THE TRACK OF MID LEVEL
WAVE...BUT FOR THE MOMENT HAVE DESIGNED FORECAST ON A MORE MODEST
WESTERN TRACK WHICH WOULD PLACE GREATER THREAT FOR PRECIPITATION/
SNOWFALL ACROSS THE WESTERN CWA LATER SUNDAY NIGHT INTO MONDAY ALONG
THE LOWER TO MID LEVEL FRONTOGENETIC ZONE...WITH DRY SLOT PUNCHING
IN NEAR KFSD AND EASTWARD...THEN PRECIP WRAPPING EASTWARD DURING THE
DAY MONDAY. A LOT OF DETAILS WILL SHAKE OUT THE NEXT DAY OR TWO...
BUT WOULD NOT BE SURPRISED TO END UP WITH A HIGHLIGHT WORTHY EVENT
GIVEN THE CURRENT CONSENSUS. MOST GUIDANCE WOULD FIND IT DIFFICULT
TO GET MUCH PAST THE LOWER 40S ON FULL MIXING ON MONDAY WITH
EXCEPTION OF THE FAR WEST AND SOUTHEAST...AND USED A BLEND OF RAW
GUIDANCE TO ACCOUNT FOR THIS WITH FORECAST FROM MONDAY INTO MONDAY
NIGHT.
TUESDAY QUIET WITH WEAK RIDGING BUILDING INTO THE AREA. KEPT IN THE
VERY SMALL POPS ON WEDNESDAY TO REFLECT WAVE IN NORTHWEST FLOW. NOT
MUCH POTENTIAL FOR MOISTURE RETURN...BUT VERY COOL IN THE MID LEVELS
AND WILL BE LIKELY BE UNSTABLE ENOUGH FOR SOME MID LEVEL SHOWERS.
/CHAPMAN
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
ISSUED BY NATIONAL WEATHER SERVICE CORPUS CHRISTI TX
956 AM CDT THU APR 12 2012
.DISCUSSION...PATCHY LIGHT RAIN/SPRINKLES HAVE DEVELOPED THIS
MORNING ACROSS PORTIONS OF THE CENTRAL AND EASTERN ZONES...NEAR
THE ESCARPMENT. 06Z GFS AND 12Z NAM ALONG WITH HRRR HINTING AT QPF
ACROSS THE EASTERN CWA THROUGH THE AFTERNOON NEAR THE EDGE OF THE
LOW LEVEL THETA-E RIDGE AXIS. INSERTED ISOLATED SHOWERS INTO THE
FORECAST FOR CENTRAL AND EASTERN ZONES FOR THE REMAINDER OF THE
MORNING AND INTO THE AFTERNOON. ATTENTION EARLY THIS EVENING TURNS
OUT WEST ALONG THE RIO GRANDE AS ISOLATED THUNDERSTORMS POSSIBLY
DEVELOP.
WFO CRP WILL CONTINUE BACKING UP WFO EWX THROUGH 18Z. AFTERNOON
FORECAST PACKAGE WILL BE COMPLETED BY WFO EWX.
&&
.PREV DISCUSSION... /ISSUED 618 AM CDT THU APR 12 2012/
AVIATION...
MOIST SELY LOW LEVEL WINDS WILL KEEP A WARM AND HUMID AIRMASS
OVER S CENTRAL TX FOR THE NEXT 24 HOURS. WIDESPREAD MVFR CIGS
DEVELOPED OVERNIGHT AND WILL CONTINUE THRU ABOUT MID MORNING OR
16-17Z Z BEFORE LIFTING TO VFR. ISOLATED -SHRA WILL DRIFT EASTWARD
NORTH OF KAUS IN ASSOCIATED WITH A WEAK UPPER AIR DISTURBANCE.
OTHERWISE VFR CONDITIONS THIS AFTERNOON AND EVENING SCT CU AT 4-5
THSD FEET AND SELY SFC WINDS AT 10-15 KNOTS. ISOLATED TSRA COULD
DRIFT TO NEAR KDRT BETWEEN 23Z AND 04Z. OTHERWISE VFR THIS EVENING
WITH MVFR CIGS QUICKLY DEVELOPING 04Z-05Z ALONG THE I35 CORRIDOR
AND SPREADING WESTWARD TO KDRT AFTER 08Z.
PREV DISCUSSION... /ISSUED 403 AM CDT THU APR 12 2012/
DISCUSSION...
THE UPPER LEVEL RIDGE AXIS EXTENDS FROM TX UP THROUGH THE GREAT
PLAINS TO SOUTHERN CANADA THIS MORNING. AN UPPER LEVEL TROUGH HAS
MOVED ON TO THE WEST COAST. A SHORTWAVE TROUGH MOVING INTO THE
BASE OF THE RIDGE PRODUCED SHOWERS AND THUNDERSTORMS OVERNIGHT
WHICH ARE DISSIPATING. IN THE SHORT TERM...THU WILL BE DRY WITH
NEAR NORMAL HIGH TEMPS UNDER THE INFLUENCE OF THE UPPER RIDGE. AS
THE UPPER PATTERN CONTINUES TO PROGRESS TO THE EAST THE RIDGE WILL
BEGIN TO MOVE AWAY FROM TX. THIS WILL ALLOW FOR A SLIGHT CHANCE
FOR THUNDERSTORMS THIS EVENING ACROSS THE RIO GRANDE PLAINS. SPC
SLIGHT RISK AREA IS JUST TO THE NORTHWEST OF OUR CWA. DO NOT
EXPECT ANY SEVERE STORMS. AS THE UPPER LEVEL TROUGH APPROACHES
THIS WEEKEND CHANCES FOR PRECIP WILL INCREASE. SAT THERE WILL BE A
SLIGHT CHANCE ACROSS THE EAST. SAT NIGHT THE SLIGHT CHANCE WILL
SPREAD ACROSS THE ENTIRE CWA. THEN SUN A FRONTAL BOUNDARY WILL
BEGIN TO AFFECT OUR AREA. BEST CHANCES FOR STORMS WILL BE SUN
NIGHT AND MON. MODELS ARE SHOWING HIGH CAPE AND STRONG VERTICAL
WIND SHEAR ALONG WITH ABUNDANT DEEP MOISTURE. THERE IS A CHANCE
STORMS WILL BE SEVERE SUN NIGHT WITH HEAVY RAIN POSSIBLE. AM NOT
CONFIDENT ENOUGH TO INCLUDE SEVERE MENTION AT THIS TIME...BUT
POSSIBILITY EXISTS. UPPER TROUGH WILL LIFT OUT OF THE SOUTHERN
PLAINS MON NIGHT AND THE FLOW WILL BECOME MAINLY ZONAL THROUGH THE
END OF THE FORECAST PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 83 67 83 70 84 / 20 - 10 10 20
AUSTIN BERGSTROM INTL AIRPORT 83 65 83 68 84 / 20 - 10 10 20
NEW BRAUNFELS MUNI AIRPORT 82 64 82 67 83 / 20 - 10 10 10
BURNET MUNI AIRPORT 81 65 82 67 83 / 20 - 10 10 20
DEL RIO INTL AIRPORT 84 68 86 69 89 / - 20 10 10 -
GEORGETOWN MUNI AIRPORT 81 65 81 67 82 / 20 - 10 10 20
HONDO MUNI AIRPORT 83 66 83 67 86 / 10 - 10 10 10
SAN MARCOS MUNI AIRPORT 81 65 81 68 83 / 20 - 10 10 20
LA GRANGE - FAYETTE REGIONAL 81 66 81 69 83 / 20 - 10 10 20
SAN ANTONIO INTL AIRPORT 82 67 83 69 84 / 20 - 10 10 10
STINSON MUNI AIRPORT 83 66 83 69 85 / 10 - 10 10 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...99
SYNOPTIC/GRIDS...99
AREA FORECAST DISCUSSION
NWS SPOKANE WA
511 AM PDT Thu Apr 12 2012
.SYNOPSIS...
Showers will continue today with cooler and breezier conditions
expected with the showery pattern continuing through the weekend. A
series of systems will move through the region next week bringing
more unsettled weather.
&&
.DISCUSSION...
Today and tonight: As of 2:00 AM Thursday morning, the closed
upper level low pressure circulation is at 140 W 45 N. This upper
level low is expected to shift southeast toward northern
California through tonight. The short wave trough that moved
through the region last night is swinging into the Idaho Panhandle
as is expected to moved to the northeast of the region through the
early morning hours. Precipitation amounts with this disturbance
were not very impressive. Hydrographs in the Idaho Panhandle do
show some rises in response to some snow melt, but do not expect
last night`s precipitation or any from this afternoon to have much
of an impact. The Flood Watch for the Coeur d`Alene River at
Cataldo will remain in effect and will make a decision on what to
do with it late this morning, but the lack of rainfall overnight
may not quite push it up to flood stage. Will continue to monitor
through the morning hours.
There are a couple other little disturbances moving across or into
the western United States behind this shortwave through the
southerly flow. The first is moving into northern Oregon at this
time. Satellite imagery and observations across this area show
some mid level cloud cover associated with this weak wave.
Pendleton`s radar also shows some lite returns, but as of this
time no precipitation has been recorded. Models are not very
excited with this wave as it moves through the region this
morning. Both the NAM and the HRRR models generate some light
precipitation from the northeast Blue Mountains northeast into the
Central Panhandle and up along the east slopes of the northern
Cascades, but other than that only cloud cover and maybe some
sprinkles expected.
The second little wave is expected to move into the region during
the afternoon hours. This will likely play a role in enhancing
showers across much of the region. Models have been doing a poor
job in resolving moisture parameters over the last couple of days.
Due to this fact, confidence is not high with any convective
parameters. With that said, it does appear that the models are
doing a better job this morning capturing observed dew point
temperatures. Both the NAM and GFS CAPE values look much more
reasonable for this afternoon. However, the GFS still looks to be a
bit too unstable over the Idaho Panhandle and preferred the NAM in
this aspect. Most unstable CAPE values off of the NAM generally
range between 200 and 350 J/KG with the higher values across the
southwestern half of the region following this second disturbance.
This is sufficient enough to generate a few lightning strikes, but
considering that models have not had a great track record, decided
to not put thunderstorms into the forecast. The more favorable
areas for any thunderstorms wold be across the higher terrain,
especially over the northeast Blue Mountains and Cascades.
However, even a lightning strike or two will be possible across
the basin as well.
Temperatures will be noticeably cooler this afternoon due to much
colder 850 mb temperatures, especially across the northeastern
half of the region (between 4 to 9 degrees Celsius cooler across
this area compared to yesterday afternoon). More cloud cover will
help to keep temperatures cooler today compared to yesterday as
well. Winds will be a little breezy this afternoon as good mixing
bring down slightly stronger winds aloft with gusts up to 20 to 25
mph in places. /SVH
Friday through Sunday night...On Friday a large closed low will move
into California with a second low over British Columbia and
Alberta. The Inland Northwest will be in between these two
features. However cold temperatures aloft with 500mb values of
-28C will promote an unstable atmosphere during peak heating with
showers likely developing over the mountains with a few valley
showers also possible. There is also chance for morning showers
over the Blue Mountains and Camas Prairie with a weak wave moving
up out of NE Oregon. A stray lightning strike is also possible
but with marginal convective parameters will leave out of
forecast. On Saturday and Sunday the closed low to the north
becomes an open wave and slowly drops southeast into the area.
The ECMWF has been the most consistent with this idea with the GFS
and NAM trending towards the ECMWF with showers lingering
especially over the mountains both Saturday and Sunday. Thus
precipitation chances were increased on Sunday especially over the
Idaho Panhandle.
Monday through Wednesday...The GFS, ECMWF, and GEM models are in
good agreement of a transition to a zonal flow pattern on Monday
with several systems expected to move through the Inland Northwest
next week. The first one arrives on Monday but is not particularly
strong with models generating around a tenth of an inch qpf
valleys and a quarter inch mountains with snow levels 5000-6000
feet. A stronger system arrives Wednesday bringing more unsettled
conditions. Yet another system is possible late next week.
Precipitation chances were increased Monday and Wednesday with the
expected unsettled weather.
Near normal temperatures are expected through the extended period
although cloud cover and precipitation will likely play a role for
high temperatures and may result in below normal readings at times. JW
&&
.AVIATION...
12Z TAFS: Stratus has developed behind the exiting system early this
morning across the northern valleys including at KSFF and KCOE. LIFR
cigs at KLWS is not being resolved at all by model guidance, but
this should break up and lift quickly with sunrise. All areas will
see a chance for some afternoon convection, but best chances will be
over the mountains. Models generally just show some disorganized
shower activity, which will be highly diurnal in nature. This is
addressed with VCSH in the TAFs through the afternoon. A weak
disturbance moving north into the region this afternoon may act to
enhance the shower activity, but it will continue to weaken as it
approaches the region. There is a small chance for a thunderstorm at
any TAF site with the likeliest spot over the Blue Mountains that
could potential drift into KLWS or KPUW. /SVH
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 55 37 55 36 56 37 / 40 20 20 10 20 20
Coeur d`Alene 54 36 54 35 56 37 / 40 20 20 10 30 20
Pullman 52 34 55 34 54 36 / 50 40 20 10 20 10
Lewiston 58 38 59 39 59 40 / 40 40 20 10 10 10
Colville 58 38 58 36 62 38 / 50 20 20 10 40 40
Sandpoint 54 36 53 34 55 34 / 60 30 30 10 40 40
Kellogg 51 35 51 33 54 35 / 60 30 40 10 40 20
Moses Lake 61 36 62 36 62 38 / 20 20 10 0 10 10
Wenatchee 60 38 60 39 62 41 / 20 20 10 0 0 0
Omak 61 38 60 35 62 38 / 20 20 10 10 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS SPOKANE WA
258 AM PDT Thu Apr 12 2012
.SYNOPSIS...
Showers will continue today with cooler and breezier conditions
expected with the showery pattern continuing through the weekend. A
series of systems will move through the region next week bringing
more unsettled weather.
&&
.DISCUSSION...
Today and tonight: As of 2:00 AM Thursday morning, the closed
upper level low pressure circulation is at 140 W 45 N. This upper
level low is expected to shift southeast toward northern
California through tonight. The short wave trough that moved
through the region last night is swinging into the Idaho Panhandle
as is expected to moved to the northeast of the region through the
early morning hours. Precipitation amounts with this disturbance
were not very impressive. Hydrographs in the Idaho Panhandle do
show some rises in response to some snow melt, but do not expect
last night`s precipitation or any from this afternoon to have much
of an impact. The Flood Watch for the Coeur d`Alene River at
Cataldo will remain in effect and will make a decision on what to
do with it late this morning, but the lack of rainfall overnight
may not quite push it up to flood stage. Will continue to monitor
through the morning hours.
There are a couple other little disturbances moving across or into
the western United States behind this shortwave through the
southerly flow. The first is moving into northern Oregon at this
time. Satellite imagery and observations across this area show
some mid level cloud cover associated with this weak wave.
Pendleton`s radar also shows some lite returns, but as of this
time no precipitation has been recorded. Models are not very
excited with this wave as it moves through the region this
morning. Both the NAM and the HRRR models generate some light
precipitation from the northeast Blue Mountains northeast into the
Central Panhandle and up along the east slopes of the northern
Cascades, but other than that only cloud cover and maybe some
sprinkles expected.
The second little wave is expected to move into the region during
the afternoon hours. This will likely play a role in enhancing
showers across much of the region. Models have been doing a poor
job in resolving moisture parameters over the last couple of days.
Due to this fact, confidence is not high with any convective
parameters. With that said, it does appear that the models are
doing a better job this morning capturing observed dew point
temperatures. Both the NAM and GFS CAPE values look much more
reasonable for this afternoon. However, the GFS still looks to be a
bit too unstable over the Idaho Panhandle and preferred the NAM in
this aspect. Most unstable CAPE values off of the NAM generally
range between 200 and 350 J/KG with the higher values across the
southwestern half of the region following this second disturbance.
This is sufficient enough to generate a few lightning strikes, but
considering that models have not had a great track record, decided
to not put thunderstorms into the forecast. The more favorable
areas for any thunderstorms wold be across the higher terrain,
especially over the northeast Blue Mountains and Cascades.
However, even a lightning strike or two will be possible across
the basin as well.
Temperatures will be noticeably cooler this afternoon due to much
colder 850 mb temperatures, especially across the northeastern
half of the region (between 4 to 9 degrees Celsius cooler across
this area compared to yesterday afternoon). More cloud cover will
help to keep temperatures cooler today compared to yesterday as
well. Winds will be a little breezy this afternoon as good mixing
bring down slightly stronger winds aloft with gusts up to 20 to 25
mph in places. /SVH
Friday through Sunday night...On Friday a large closed low will move
into California with a second low over British Columbia and
Alberta. The Inland Northwest will be in between these two
features. However cold temperatures aloft with 500mb values of
-28C will promote an unstable atmosphere during peak heating with
showers likely developing over the mountains with a few valley
showers also possible. There is also chance for morning showers
over the Blue Mountains and Camas Prairie with a weak wave moving
up out of NE Oregon. A stray lightning strike is also possible
but with marginal convective parameters will leave out of
forecast. On Saturday and Sunday the closed low to the north
becomes an open wave and slowly drops southeast into the area.
The ECMWF has been the most consistent with this idea with the GFS
and NAM trending towards the ECMWF with showers lingering
especially over the mountains both Saturday and Sunday. Thus
precipitation chances were increased on Sunday especially over the
Idaho Panhandle.
Monday through Wednesday...The GFS, ECMWF, and GEM models are in
good agreement of a transition to a zonal flow pattern on Monday
with several systems expected to move through the Inland Northwest
next week. The first one arrives on Monday but is not particularly
strong with models generating around a tenth of an inch qpf
valleys and a quarter inch mountains with snow levels 5000-6000
feet. A stronger system arrives Wednesday bringing more unsettled
conditions. Yet another system is possible late next week.
Precipitation chances were increased Monday and Wednesday with the
expected unsettled weather.
Near normal temperatures are expected through the extended period
although cloud cover and precipitation will likely play a role for
high temperatures and may result in below normal readings at times. JW
&&
.AVIATION...
06Z TAFS: A disturbance moving up from the south will bring
showers across eastern TAF sites Wednesday night, primarily
before 09-11Z. With the loss of daytime heating, the threat of
thunder has diminished, although a stray storm cannot be ruled
out. Primarily VFR conditions are expected, except for local MVFR
conditions in heavier showers. Western TAFS will find mainly an
isolated shower threat. The shower threat wanes around TAF sites
into the morning. Another weak wave passes Thursday afternoon,
once again bringing a threat of showers. These are expected to be
more isolated to widely scattered in nature, before waning after
sunset. Expect some breezy conditions in the afternoon/early
evening hours Thursday. /J. Cote`
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 55 37 55 36 56 37 / 40 20 20 10 20 20
Coeur d`Alene 54 36 54 35 56 37 / 40 20 20 10 30 20
Pullman 52 34 55 34 54 36 / 50 40 20 10 20 10
Lewiston 58 38 59 39 59 40 / 40 40 20 10 10 10
Colville 58 38 58 36 62 38 / 50 20 20 10 40 40
Sandpoint 54 36 53 34 55 34 / 60 30 30 10 40 40
Kellogg 51 35 51 33 54 35 / 60 30 40 10 40 20
Moses Lake 61 36 62 36 62 38 / 20 20 10 0 10 10
Wenatchee 60 38 60 39 62 41 / 20 20 10 0 0 0
Omak 61 38 60 35 62 38 / 20 20 10 10 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
430 AM MDT THU APR 12 2012
.SHORT TERM...TODAY THROUGH FRIDAY...
THE RUC 500MB ANALYSIS SHOWS A STRONG SHORTWAVE MOVING NORTHWARD
ACROSS NORTHERN CO AND SOUTHERN WY AT THIS HOUR. THE FORCING FROM
THIS SHORTWAVE IS RESPONSIBLE FOR THE LIGHT RAIN ACTIVITY CURRENTLY
MOVING NORTHWARD OVER THE NE PANHANDLE. THE GFS SHOWS A NARROW
TONGUE OF SMALL SFC INSTABILITY OVER THE PANHANDLE...WITH LI VALUES
BETWEEN 0 AND -2C...HOWEVER THE DECREASING TREND OF REFLECTIVITY
OVER THE LAST HOUR SUGGESTS THAT ANY TSTM ACTIVITY WILL BE REALLY
LIMITED. SFC ANALYSES SHOW THE SFC TROUGH AND COLD FRONT JUST TO
THE WEST OF CHEYENNE...WITH DRIER AIR AND SW WINDS TO THE WEST AND
MOIST SOUTHERLY WINDS TO THE EAST OF THIS FEATURE. THE FRONT WILL
PROGRESS EASTWARD OVER THE CWA THIS MORNING...REACHING THE NE
PANHANDLE BY LATE MORNING AND SCOURING OUT ANY REMAINING LOW
CLOUDINESS AND SHOWER ACTIVITY. LLVL GRADIENTS INCREASE BEHIND THE
FRONT WITH 700MB WINDS AROUND 40-50 KTS BETWEEN 12 AND 18Z OVER
MAINLY CONVERSE AND NIOBRARA COUNTIES. THIS WILL LIKELY CAUSE WIND
GUSTS AT ARLINGTON TO APPROACH HIGH WIND CRITERIA FOR A SHORT
TIME...BUT CONFIDENCE IS NOT HIGH ENOUGH TO ISSUE A WARNING AT THIS
TIME. OTHERWISE...EXPECT RELATIVELY DRY CONDITIONS OVER THE CWA
THROUGH LATE MORNING IN THE SUBSIDENCE BEHIND THE SHORTWAVE AND
FROPA. ANOTHER WEAKER SHORTWAVE MOVES OVER THE CWA DURING THE AFTN
AND EVENING. DUE TO THE LIFT FROM THIS FEATURE ALONG WITH 500MB
TEMPS DROPPING TO -20C BY AFTN AND LI VALUES 0 TO -1C...INCLUDED A
SLIGHT CHANCE OF TSTMS OVER MOST AREAS.
RELATIVELY QUIET WEATHER DAY ON FRI WITH WEAK SOUTHWESTERLY MIDLEVEL
FLOW AND NO DISCERNIBLE PERTURBATIONS IN THE FLOW. TEMPS WILL BE
COOL WITH 700MB TEMPS AROUND -2C. WITH WEAK LLVL GRADIENTS OVER THE
AREA WINDS WILL BE WEAK WESTERLY. THERE IS ENOUGH MIDLEVEL (700-500
MB) MOISTURE IN THE FLOW TO INCLUDE A CHANCE TO SLIGHT CHANCE OF
RAIN SHOWERS OVER AREAS TO THE WEST OF THE LARAMIE RANGE. ATTENTION
THEN TURNS TO THE POTENTIAL MAJOR WINTER STORM DURING THE WEEKEND.
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
MUCH COOLER AND WET WEATHER WILL AFFECT THE REGION SATURDAY THROUGH
SUNDAY NIGHT. THIS EVENT COULD HAVE MAJOR IMPACTS ON TRAVEL...OUTDOOR
ACTIVITIES AND LIVESTOCK DURING THAT TIME WITH SIGNIFICANT ACCUMULATING
SNOW POSSIBLE.
CLOUDS WILL INCREASE OVER THE CWA FRIDAY NIGHT WITH SHOWERS BECOMING
MORE WIDESPREAD THROUGH SATURDAY AFTERNOON. ISOLATED THUNDERSTORMS
WILL ALSO BE POSSIBLE SATURDAY AFTERNOON AND EARLY EVENING. ALL OF
THE PRECIPITATION IS AHEAD OF THE APPROACHING MID AND UPPER LEVEL LOW
WHICH WILL BE NEAR THE FOUR CORNERS AREA BY 00Z SUNDAY. THE
ASSOCIATED SURFACE LOW WILL BE DEVELOPING OVER EASTERN COLORADO
SATURDAY AFTERNOON. THE 00Z MODELS...OTHER THAN THE NAM...HAVE
BECOME MORE CONSISTENT WITH MOVEMENT OF THE SYNOPTIC FEATURES AND THE
QPF. BY 12Z SUNDAY...THE STORM SYSTEM WILL BE OVER EASTERN COLORADO
AND THEN WILL MOVE SLOWLY NORTHEAST THROUGH 00Z MONDAY BEFORE
ACCELERATING SUNDAY NIGHT AND MONDAY. THE PRECIPITATION WILL CHANGE
FROM RAIN TO SNOW SATURDAY NIGHT AND EARLY SUNDAY MORNING AS THE
SURFACE AND 700 MB TEMPERATURES COOL AND THE 1000 TO 500 MB THICKNESS
VALUES LOWER. THE ACCUMULATING SNOW WILL BE FOCUSED ON THE WEST PART
OF THE CWA EARLY SATURDAY NIGHT AND THEN SHIFT EAST TO THE SOUTHEAST
HALF OF THE CWA LATER SATURDAY NIGHT AND FOR MUCH OF SUNDAY. ALONG
WITH THE SURFACE FORCING WILL BE DIFFLUENCE ALOFT AND MID LEVEL
CONVERGENCE. SNOWFALL AMOUNTS WILL BE UP TO A FOOT OVER AND NEAR
THE SNOWY AND SIERRA MADRE RANGES SATURDAY NIGHT AND THEN BETWEEN 6
AND 14 INCHES OVER THE SOUTHEAST HALF OF THE CWA LATE SATURDAY NIGHT
THROUGH SUNDAY. ALONG WITH THE SNOW WILL BE STRONG NORTHEAST WINDS
GUSTING AS HIGH AS 50 MPH. BLIZZARD CONDITIONS COULD RESULT AT TIMES
OVER THAT AREA LATE SATURDAY NIGHT AND SUNDAY. A LESS AMPLIFIED
WIND FLOW ALOFT WILL BE OVER THE ROCKIES INTO MID WEEK. SEVERAL
SHORTWAVE TROUGHS AND A RELATIVELY UNSTABLE ATMOSPHERE WILL PRODUCE
SHOWERS MONDAY AND TUESDAY AND AGAIN NEXT THURSDAY. TEMPERATURES
WILL SLOWLY MODERATE THROUGH THAT TIME. FOR THE LATER PARTS OF THIS
FORECAST FOLLOWED MORE CLOSELY THE 00Z ECMWF.
&&
.AVIATION...06Z TAF ISSUANCE...
LOW CLOUDS WILL CONTINUE OVER THE PLAINS THROUGH THE OVERNIGHT
HOURS. BELIEVE THAT MOST OF THE TAF SITES WILL SEE LOW END MVFR CIGS
DUE TO THE BREEZY SOUTHEAST WINDS WHICH WILL KEEP SOME LOW LEVEL
MIXING. RADAR IMAGERY SHOWS LIGHT RAIN SHOWERS NEAR KLAR AND KCYS SO
INCLUDED THEM IN THE TAF OVER THE NEXT FEW HOURS. A COLD FRONT WITH
DRIER AIR WILL MOVE FROM WEST-TO-EAST OVER THE SITES THROUGH THE
MORNING HOURS. THE FRONT WILL PASS OVER KCYS AROUND 09Z AND OVER THE
NE SITES BETWEEN 15Z AND 18Z. THE DRIER AIR WILL EFFECTIVELY END
THIS LOW CLOUD EVENT WITH VFR CONDITIONS PREVAILING. WINDS BEHIND
THE FRONT WILL BE BREEZY WITH SUSTAINED WINDS 20 KTS AND SOME GUSTS
TO 30 KTS POSSIBLE.
&&
.FIRE WEATHER...
DRY AND BREEZY CONDITIONS WILL OCCUR THIS AFTERNOON OVER SOUTHEAST
WYOMING AND THE NEBRASKA PANHANDLE AFTER A COLD FRONT MOVES OVER THE
AREA THIS MORNING...WHICH WILL RESULT IN AN ELEVATED FIRE DANGER
THREAT TO THE EAST OF THE LARAMIE RANGE. DUE TO THE DRIER
AIR...MINIMUM RELATIVE HUMIDITIES WILL BE IN THE 15 TO 20 PERCENT
RANGE TO THE EAST OF THE LARAMIE RANGE. IN ADDITION...WESTERLY
WINDS WILL BE SUSTAINED AT 20 TO 25 MPH WITH OCCASIONAL GUSTS TO 35
MPH. A STORM SYSTEM MOVING INTO THE AREA ON SAT AFTN THROUGH SUN
EVENING HAS THE POTENTIAL TO BRING WIDESPREAD RAIN AND SNOW...ENDING
ALL FIRE WEATHER CONCERNS THROUGH EARLY NEXT WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
FINCH/WEILAND
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
332 PM MDT THU APR 12 2012
.SHORT TERM...SCATTERED STORMS CONTINUE ACROSS LOGAN...NORTHERN
WASHINGTON AND EASTERN MORGAN COUNTIES ON THE WESTERN EDGE OF THE
STABLE AIR WHERE LAPS SURFACE ANALYSIS SHOWING CAPES FROM
1000-1500 J/KG. FURTHER NORTHEAST...CAPES MINIMAL BUT ARE
INCREASING. STORMS ARE NOW FIRING ACROSS PHILLIPS COUNTY. STILL
DECENT SHEAR IN THIS REGION WITH LOW LEVEL SOUTHEASTERLIES AND
WESTERLY FLOW ALOFT. TORNADO WATCH CURRENTLY IN EFFECT FOR THAT
REGION THROUGH 02Z. POTENTIAL FOR THOSE STORMS TO PRODUCE
HAIL...WIND ALONG WITH A FEW TORNADOES. FURTHER WEST...WEAK
NORTHERLY SURGE HELPED TO AID IN QUITE A BIT OF VIRGA TYPE SHOWERS
ALONG FRONT RANGE DURING THE AFTERNOON. ALSO A FEW REPORTS OF RAIN
HITTING THE GROUND. SHOWERS CURRENTLY CONCENTRATED ACROSS NORTHERN
AND EASTERN WELD COUNTY. SCATTERED SHOWERS ALSO OCCURRING ACROSS
MOUNTAINS...WITH LATEST WEB CAMS INDICATION SOME SNOW AND RAIN
ACROSS THE HIGHER ELEVATIONS OF SUMMIT AND GRAND COUNTIES. FOR
TONIGHT...CONVECTION OVER NORTHEAST CORNER TO SLIDE INTO NEBRASKA
DURING THE EVENING AS BACK EDGE OF SHORTWAVE HEADS EAST AND DRIER
AIR FROM SOUTH MOVES ACROSS AREA. WILL KEEP A SLIGHT CHANCE OF
STORMS IN THAT AREA THROUGH THE EVENING. ELSEWHERE ACROSS
PLAINS...STILL SOME QUESTION IF SHOWER ACTIVITY WILL CONTINUE...AS
LATEST NAM AND GFS STILL GENERATE SOME LIGHT QPF FOR MUCH OF THE
AREA THROUGH THE EVENING. BUT LATEST RUC AND HRR SHOWS THE SHOWERS
CONFINED TO WELD AND MORGAN COUNTIES. WILL ADD A SLIGHT CHANCE TO
THE EARLY EVENING GRIDS FOR EASTERN WELD AND MORGAN COUNTIES.
ACROSS MOUNTAINS... SOUTHWEST FLOW ALOFT CONTINUES. CROSS SECTIONS
SHOW SOME DECREASE IN MOISTURE...STILL ENOUGH TO KEEP A CHANCE OF
SNOW GOING. ON FRIDAY...THE SOUTHWEST FLOW ALOFT WILL CONTINUE TO
INCREASE AHEAD OF THE APPROACHING TROUGH WITH MODELS SHOWING A JET
MAX MOVING ACROSS WESTER COLORADO. CROSS SECTIONS GRADUALLY
INCREASE THE MOUNTAIN MOISTURE DURING THE AFTERNOON WITH THE NAM
SHOWING SOME INCREASE IN MID LEVEL QG ASCENT. THE DEEPER MOISTURE
STILL APPEARS WEST OF THE CFWA. THE GFS STILL IS DRIER. SO...WILL
KEEP THE CHANCE POPS GOING FOR THE MOUNTAINS FOR NOW WITH SLIGHT
CHANCE POPS FOR NORTH AND MIDDLE PARKS. TEMPERATURE AND THICKNESS
PROGS SUGGEST A MIX OF RAIN AND SNOW FOR THE MOUNTAINS...WITH
MAINLY SNOW ACROSS THE RIDGES. AS FOR PLAINS...MODELS SHOW
SOUTHWEST WINDS INCREASING BY AFTERNOON...THOUGH HINTS AT A
SURFACE CYCLONE DEVELOPING NORTH OF DENVER. AIRMASS WILL BE
DRY...NO POPS EXPECTED. LATEST GUIDANCE SHOWS HIGHS ACROSS PLAINS
IN THE LOWER AND MID 60S...WHICH LOOKS REASONABLE BASED ON
THICKNESS PROGS. CURRENT TEMPERATURE GRIDS IN LINE WITH
GUIDANCE...SEEMS REASONABLE.
.LONG TERM...MODELS CONTINUE TO CONVERGE UPON ONE SOLUTION FOR
THIS WEEKEND...ONE THAT CONTAINS A BETTER POTENTIAL FOR
SIGNIFICANT PRECIPITATION AND COLDER TEMPERATURES AREAWIDE.
NAM...GFS...EUROPEAN...CANADIAN GEM AND SREF HAVE ALL LATCHED ON
THE DEEPENING TROUGH PASSING OVER THE EASTERN GREAT BASIN AND THE
CLOSED MID/UPPER LEVEL CYCLONE NEARING THE 4-CORNERS FRIDAY NIGHT.
AHEAD OF THIS TROUGH...LOW...MID AND UPPER LEVEL FLOW SOUTH-
SOUTHWESTERLY FRIDAY NIGHT INTO SATURDAY MORNING WHICH SHOULD KEEP
TEMPERATURES ON THE SEASONABLY MILD SIDE. MODELS HINT AT A SHORT
WAVE DISTURBANCE EJECTING NORTHEAST OUT OF THE BASE OF THE MAIN
TROUGH AND OVER THE NORTHERN MTNS FRIDAY NIGHT. COULD SEE A ROUND
OF RAIN AND SNOW SHOWERS IN THE HIGH COUNTRY WITH THIS WEAK
PERTABATION IN THE FLOW...BUT NOT LOOKING FOR MUCH IN THE WAY OF
MEASURABLE PCPN YET. THE FOOTHILLS AND PLAINS SHOULD REMAIN DRY
OVERNIGHT WITH THE DRYING EFFECTS OF A WEST-SOUTHWESTERLY
DOWNSLOPE FLOW.
ON SATURDAY...THE LATEST MODEL RUN SHOWS THE 500MB LOW PASSING
OVER THE 4-CORNERS AREA DURING THE DAY...A TAD SLOWER THAN WAS
PROGGED BY THE LAST COUPLE MODEL RUNS. AS IT DOES Q-G OMEGA
FIELDS INDICATE A STEADY INCREASE IN LARGE SCALE ASCENT OVER
NORTHERN AND NORTHEAST COLORADO. MODELS ALSO SHOW A SFC COLD
FRONT DROPPING SOUTH OUT OF WYOMING INTERACTING WITH AN INCREASING
MOIST SOUTHERLY BOUNDARY LAYER FLOW ON THE PLAINS. NAM...GFS AND
ECMWF ALL INDICATE LIGHT QPF BREAKING OUT ALONG THE WYOMING BORDER
AROUND MIDDAY WITH BANDED LIFT ALOFT...AND OVER REMAINING PORTIONS
OF THE FRONT RANGE AND NORTHEAST PLAINS BY 00Z/SUNDAY...IF NOT
SOONER. TEMPERATURES...IE. WETBULB TEMPS...STILL LOOK TOO WARM FOR
SNOW AT LOWER ELEVATIONS. HOWEVER IT/S LIKELY WE/LL SEE
TEMPERATURES AND SNOW LEVELS STEADILY LOWERING THROUGH THE DAY IN
THE HIGH COUNTRY...WITH ANY SNOW ACCUMULATION ON THE LIGHT SIDE
AND CONFINED TO HIGHER RIDGES FROM SUMMIT COUNTY NORTHWARD.
IT/S SATURDAY NIGHT AND SUNDAY WHEN MODELS PAINT A VERY WET AND
EVEN SNOWY PICTURE FOR OUR PART OF THE STATE. SUBTLE DIFFERENCES
IN THE MODELS BEGIN TO APPEAR AT THIS POINT WHICH ONLY ADDS
UNCERTAINTY TO THE FORECAST BEYOND SATURDAY. AS IT STANDS NOW...A
CONSENSUS OF THE MODELS SHOW THE UPPER LOW TRACKING EAST ALONG
THE COLORADO-NEW MEXICO BORDER SATURDAY NIGHT...THEN NORTHEAST
OVER SOUTHEAST COLORADO AND WESTERN KANSAS ON SUNDAY. GREATEST
SYNOPTIC SCALE LIFT GENERATED IN THE NORTHWEST QUAD OF THIS
CYCLONE...WHICH MODELS SHOW PASSING OVER THE NORTH CENTRAL MTNS
AND NORTHERN FRONT RANGE AND FOOTHILLS...SATURDAY NIGHT...AND OVER
THE CENTRAL AND SOUTHERN FRONT RANGE AND FOOTHILLS AND NORTHEAST
PLAINS DURING THE DAY SUNDAY. MODELS CONTINUE TO GO HIGH WITH QPF
AND SNOW ACCUMULATIONS WITH THIS STORM SYSTEM...ALTHOUGH PERHAPS
NOT AS AMBITIOUS AS BEFORE. A MAJORITY OF THE MODELS SHOW
SOUTHWEST-TO-NORTHEAST ORIENTED BANDS OF 1 TO 2 INCH QPF ACROSS
THE AREA BY LATE SUNDAY AFTERNOON...AND 1 TO 2 AND A HALF FOOT
SNOW ACCUMS BY 00Z/MONDAY IN THE FRONT RANGE MTNS AND FOOTHILLS.
MODELS EVEN SHOW PRETTY RESPECTABLE SNOW TOTALS ON THE PLAINS...
WITH MOIST FLOW WRAPPING AROUND THE BACK SIDE OF THIS PASSING
TROUGH/UPPER LOW. HOWEVER ALL DEPENDS ON TEMPERATURES AS IS OFTEN
THE CASE THIS TIME OF YEAR. THE GFS...ECMWF AND CANADIAN GEM SHOW
WETBULB TEMPS COLD ENOUGH FOR ALL SNOW ON THE PLAINS SATURDAY
NIGHT AND MOST OF SUNDAY...BUT THE NAM KEEPS TEMPS A BIT TOO WARM
EXCEPT MAYBE FOR A RAIN/SNOW MIX. FOR NOW WILL GO WITH LIKELY
POPS IN THE MTNS AND VALLEYS BEGINNING SATURDAY...AND FOR THE
REMAINDER OF THE CWFA SATURDAY NIGHT AND SUNDAY.
SUNDAY NIGHT AND MONDAY...AT THIS TIME...MOST OF THE MODELS SHOW
THE UPPER LOW AND ITS PRECIPITATION MOVING OUT ON MONDAY.
ALTHOUGH THE GFS IS SLOW TO MOVE PRECIP OUT AS IT SHOWS A
DISTURBANCE IN NORTHWEST FLOW SWINGING ACROSS THE AREA DURING THE
DAY. FOR NOW...WILL HANG ONTO TO LOW POPS ON MONDAY WITH SLIGHT
WARMING.
TUESDAY AND BEYOND...GFS AND GEM INDICATE THE PASSAGE OF YET ANOTHER
WEAK MID-LEVEL DISTURBANCE EMBEDDED IN NORTHWEST FLOW ON TUESDAY.
WHEREAS THE NAM AND ECMWF SHOW A SHORTWAVE RIDGE BUILDING OVER THE
STATE. FOR NOW WILL KEEP A SLIGHT CHANCE OF LIGHT RAIN SHOWERS IN
THE FCST FOR TUESDAY. BEYOND THAT...WILL GO WITH DRY AND WARMER
CONDITIONS PRETTY MUCH EVERYWHERE.
&&
.AVIATION... STILL SOME SHOWERS HOLDING ON NORTH AND EAST OF THE
DENVER AREA...SHOULD CONTINUE TO HEAD EAST THROUGH THE EVENING.
WINDS FINALLY HOLDING FROM THE NORTHWEST WITH SOME GUSTS TO 20 KTS
AT DIA. NORTHWEST WINDS SHOULD CONTINUE INTO THE EVENING BEFORE
DECREASING AND SHIFTING TO THE SOUTHWEST. CEILINGS HAVE STAYED
ABOVE 7000 FEET AGL AND NOT EXPECTED TO CREATE ILS CONCERNS.
SOUTHWEST WINDS TO CONTINUE THROUGH FRIDAY...SHOULD INCREASE BY
19Z WITH SOME GUSTS TO 20 KTS POSSIBLE. VFR TO PREVAIL.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....BAKER
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS PUEBLO CO
322 PM MDT THU APR 12 2012
.SHORT TERM...
(TONIGHT AND FRIDAY)
...SEVERE STORMS POSSIBLE NEAR THE KANSAS BORDER THIS AFTERNOON...
DRYLINE AT THIS TIME APPEARS TO BE CENTERED PARALLEL AND NEAR
HIGHWAY 287/385 THROUGH ERN PORTIONS OF BACA...PROWERS...AND KIOWA
COUNTIES. DEWPOINTS OVR THE I-25 CORRIDOR HAVE MIXED OUT TO THE
LOWER TEENS. HRRR STILL SHOWING THE POTENTIAL FOR AN ISOLD STORM OR
TWO DEVELOPING ALONG THE DRYLINE IN THE NEXT HOUR OR TWO...THEN
MOVING FAIRLY QUICKLY INTO KS. ENVIRONMENT IS STILL FAVORABLE E OF
THE DRYLINE FOR THE DEVELOPMENT OF TORNADIC SUPERCELLS...THUS THE
CURRENT TOR WATCH IN EFFECT FOR THIS AREA. 4KM WRF DOES NOT DEVELOP
ANY STRONG CONVECTION IN OUR AREA. SHOULD SEE FAIRLY SHORTLY WHETHER
THE CU FIELD OVR THE FAR SERN PLAINS WILL PRODUCE ANY PERSISTENT
CONVECTION.
FARTHER W...LOW RH AND STRENGTHENING SW WINDS HAVE LED TO MARGINAL
CRITICAL FIRE WX CONDITIONS. WITH WINDS EXPECTED TO CONTINUE TO GUST
THROUGH EARLY EVE...AND MORE DRY AIR ON THE WAY...WILL LEAVE RED
FLAG INTACT FOR THE BALANCE OF THE WARNING. HAVE ALSO CONVERTED THE
FIRE WX WATCH TO A WARNING FOR TOMORROW AFTERNOON FOR THE SAN LUIS
VALLEY...WITH CONTINUED DRY CONDITIONS AND GUSTY SW WINDS. RH SHOULD
BE ABOVE CRITICAL CRITERIA TOMORROW OVR MOST OF THE REMAINDER OF THE
DISTRICT...WITH TEMPS ALOFT FALLING OFF A BIT MORE AND RESULTANT
HIGHER HUMIDITY. EXPECT TEMPS TO VARY FROM THE 50S OVR THE SAN LUIS
VALLEY...UPR ARKANSAS...AND EL PASO-TELLER...TO THE LOWER 70S OVR
THE SERN PLAINS. SHOULD BE A GENERALLY DRY DAY E OF THE DVD. ANOTHER
SHORTWAVE IN ADVANCE OF THE BIG PACIFIC TROUGH FOR THIS WEEKEND WILL
KICK OFF SOME LIGHT SHSN OVR THE DVD DURING THE AFTERNOON...AND COULD
SEE SOME LIGHT ACCUMS OVR THE DVD BY FRI EVE. MAIN SHOW WILL COME
THIS WEEKEND...HOWEVER. ROSE
.LONG TERM...
(FRIDAY NIGHT THROUGH NEXT THURSDAY)
OVERALL...MODEL SOLUTIONS HAVE TRENDED EVER SO SLIGHTLY BACK TO
THE SOUTH REGARDING THE TRACK OF THE UPPER LEVEL LOW ACROSS THE
STATE THIS WEEKEND...WHICH WOULD INCREASE THE THREAT OF HEAVY
PRECIPITATION OVER EASTERN PORTIONS OF THE AREA...ESPECIALLY
SUNDAY. FOR THE MOUNTAINS ALONG THE CONTINENTAL DIVIDE...SMALL
DIFFERENCES IN THE LOW TRACK WON`T HAVE A BIG IMPACT ON SNOW
AMOUNTS...AS ALMOST ALL MEDIUM RANGE MODELS HAVE A PROLONGED
PERIOD OF HEAVY SNOW FROM SATURDAY INTO AT LEAST SUNDAY NIGHT.
HAVE HOISTED A WINTER STORM WATCH FOR ALL OF THE HIGHER TERRAIN
ALONG THE DIVIDE...WHERE SNOW AMOUNTS COULD APPROACH 2 FEET OR
MORE BY LATE SUNDAY NIGHT. FARTHER EAST...NO HIGHLIGHTS YET AS
HEAVY SNOW WOULD BE SATURDAY NIGHT/SUNDAY AND SMALL CHANGES TO THE
TRACK OF THE UPPER LOW WILL HAVE A BIG IMPACT ON PRECIP AMOUNTS.
TAKEN AT FACE VALUE...GFS/ECMWF SUGGEST WARNING CRITERIA SNOWFALL
POSSIBLE OVER PIKES PEAK AND THE HIGHER PORTIONS OF THE
SANGRES...WITH A PERIOD OF HEAVY...WET...WIND DRIVEN SNOW OVER THE
PALMER DIVIDE SUNDAY MORNING. STILL A GOOD DEAL OF
UNCERTAINTY...THOUGH ALL MODELS SUGGEST AT LEAST SOME -SHRA/-SHSN
A GOOD BET LATE SATURDAY NIGHT INTO SUNDAY...AS COLD FRONT RACES
SOUTH AND UPPER LEVEL MOVES OVERHEAD. WILL THUS INCREASE POPS OVER
MOST OF THE EASTERN HALF OF THE AREA...EMPHASIZING A LATE
SAT/EARLY SUN WINDOW. MODELS APPEAR TO HANG ON TO LIGHT PRECIP TOO
LONG SUNDAY NIGHT INTO MONDAY...AS LOW AND MID LEVEL FLOW WILL BE
MAINLY DOWNSLOPE...SO WILL ONLY RUN WITH LOW POPS OVER THE HIGHER
TERRAIN MON INTO MON EVENING. RETURN TO WARMER AND DRIER WEATHER
BEGINS TUE AS FLAT UPPER RIDGE BUILDS OVER THE WESTERN U.S.
&&
.AVIATION...VFR CONDITIONS ARE EXPECTED FOR NEXT 24 H FOR THE TAF
SITES. GUSTY SW WINDS WILL PERSIST THROUGH FRI...REACHING PEAK
SPEEDS IN MID-LATE AFTERNOON. PERSISTENT SHSN WILL INCREASE OVR
THE CONTDVD ESPECIALLY BY LATE FRI...IN ADVANCE OF A LARGE STORM
SYSTEM THAT COULD AFFECT THE TERMINALS IN ERN CO THIS WEEKEND.
ROSE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR COZ220-222-224-
225.
WINTER STORM WATCH FROM SATURDAY MORNING THROUGH SUNDAY EVENING
FOR COZ058-060-066-068.
RED FLAG WARNING FROM NOON TO 8 PM MDT FRIDAY FOR COZ224.
&&
$$
44/10
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1021 AM MDT THU APR 12 2012
.UPDATE...ENOUGH MOISTURE IN THE MOUNTAINS ALONG WITH WEAK
OROGRAPHICS TO GENERATE SOME LIGHT SNOW SHOWERS ACROSS THE HIGHER
RIDGES ALONG THE CONTINENTAL DIVIDE. WEB CAMS ALONG I-70 NEAR THE
TUNNEL SHOWING SOME PRECIP. MAIN CONCERN THOUGH WILL BE THE SEVERE
POTENTIAL ACROSS FAR NORTHEAST CORNER LATE THIS AFTERNOON. LATEST
RUC SHOWING A BRIEF PERIOD OF SHEAR INTO THE EARLY EVENING BEFORE
FLOW BECOMES WESTERLY AT ALL LEVELS. THE RUC FORECAST SOUNDINGS
ALSO POINTING TO CAPES AROUND 1500 J/KG ROUGHLY IN THE 21Z-02Z
TIME FRAME. MODELS CONTINUE SHOW A JET MAX SLIDING ACROSS
AREA...WITH THE NORTHEAST CORNER IN FAVORABLE AREA FOR LIFT.
PREVIOUS FORECASTS PINPOINTED THIS AREA NICELY...AND STILL LOOKS
ON TRACK. ONLY CHANGE WAS TO INCLUDE A SLIGHT CHANCE OF STORMS A
BIT FURTHER WEST INTO MORGAN AND NORTHEAST WELD COUNTIES...IN CASE
THE DRY LINE DEVELOPS FURTHER WEST AS SHOWN BY NAM AND GFS. WILL
KEEP URBAN CORRIDOR AND ADJACENT PLAINS DRY AS DOWNSLOPE NORTHWEST
WINDS WILL LIMIT PRECIPITATION. OVERALL CURRENT FORECASTS LOOKING
GOOD.
&&
.AVIATION...CURRENT TAF TRENDS STILL ON TRACK. WINDS TO SHIFT TO
THE NORTHWEST BEHIND EXITING TROUGH. BOTH NAM AND GFS GENERATE
SOME SHOWERS JUST NORTH OF THE DENVER. STILL BELIEVE THE BEST
CHANCE OF SHOWERS AND STORMS TO BE WELL NORTHEAST OF THE AREA AND
SHOULD NOT HAVE ANY IMPACT ON THE AIRPORTS. SLIGHT CHANCE FOR
CEILINGS AROUND 7000 FEET AGL...WILL KEEP OUT OF TAFS AT THIS
POINT. DRAINAGE WINDS EXPECTED TONIGHT WITH NO FOG OR LOW CLOUDS.
&&
.PREV DISCUSSION... /ISSUED 420 AM MDT WED APR 12 2012/
SHORT TERM...FORECAST AREA WILL BE LEFT IN BETWEEN WEATHER SYSTEMS
TODAY AS LAST NIGHT/S UPPER TROUGH MOVES OUT ONTO THE CENTRAL
PLAINS AND THIS WEEKEND/S UPPER TROUGH MOVES ONSHORE OVER
CALIFORNIA. THE ONLY IMPACT FROM THE WEST SHOULD BE SOME CIRRIFORM
CLOUDS OVER THE MOUNTAINS DURING THE AFTERNOON. ACROSS THE
PLAINS...THERE WILL BE A MIX OF MID LAYER CLOUDS AND AREAS OF
STRATUS THIS MORNING...LEFT OVER FROM THE ROUND OF MODERATE RAIN
SHOWERS THAT MOVED OVER DURING THE EARLY MORNING HOURS. DAYTIME
INSOLATION SHOULD CLEAR OUT MOST CLOUDINESS BY MIDDAY. TEMPERATURES
SHOULD BE A LITTLE COOLER TODAY BECAUSE OF THE MOISTURE EVAPORATING
OUT OF THE GROUND FROM LAST NIGHT/S RAINS. ZONES ON THE FAR EASTERN
PLAINS COULD SEE ANOTHER ROUND OF THUNDERSTORMS DEVELOP THIS
AFTERNOON AND EARLY EVENING. MOISTURE AND INSTABILITY ARE FORECAST
TO LINGER OVER THE EASTERN COLORADO BORDER TODAY AS A LOW PRESSURE
TROUGH REMAINS IN PLACE ACROSS THE EASTERN PLAINS. SOUTHERLY LOW
LEVEL FLOW ACROSS WESTERN KANSAS WILL KEEP DEWPOINTS IN THE UPPER
40S AND LOWER 50S WHILE A FAVORABLE WIND SHEAR PROFILE DEVELOPS LATE
THIS AFTERNOON. MODEL SOUNDINGS SHOW ABOUT 1000 G/KG OF ENERGY
DURING THE AFTERNOON AND EARLY EVENING HOURS. THE ARRIVAL OF THE
JET ALOFT MAY BE THE FINAL PIECE OF THE PUZZLE FOR ORGANIZED
CONVECTION TO DEVELOP. A THIN SLICE OF THE STATE IS UNDER SLIGHT
RISK OF SEVERE THUNDERSTORMS BECAUSE OF THIS. STORMS THAT DEVELOP
SHOULD RAPIDLY MOVE EASTWARD AND OUT OF THE FORECAST AREA DURING THE
EVENING.
LONG TERM...MODELS HAVE STRONG WEST-SOUTHWESTERLY FLOW ALOFT FOR
THE FORECAST AREA FRIDAY. BY FRIDAY AFTERNOON A JET MAXIMUM IS
STRETCHED ACROSS COLORADO...SOUTHWEST-TO-NORTHEAST. THIS JET MAX
CONTINUES FRIDAY NIGHT...WITH THE FLOW ALOFT DUE SOUTHWESTERLY.
ON SATURDAY...THE STRONG SOUTHWESTERLY FLOW ALOFT IS ON THE DECREASE
AS AN UPPER TROUGH MOVES EASTWARD TOWARDS THE CWA. BY 00Z LATE
SATURDAY AFTERNOON...MODELS SHOW A CLOSED UPPER CIRCULATION JUST
NORTH OF THE FOUR CORNERS. THE GFS AND ECMWF ARE A BIT SLOWER AND
FURTHER SOUTH AND WEST WITH THESE FEATURE SATURDAY OVERNIGHT. BY
12Z EARLY SUNDAY MORNING...THE UPPER TROUGH AXIS IS JUST GETTING
INTO THE WESTERN CWA...WITH THE UPPER CIRCULATION CENTER OVER THE
SOUTHEASTERN CORNER OF OUR CWA ACCORDING TO THE GFS AND ECMWF. THE
NAM IS A BIT NORTHEAST OF THERE WITH ITS CIRCULATION CENTER. THE QG
VERTICAL VELOCITY FIELDS BRING IN UPWARD SYNOPTIC SCALE ENERGY BY
FRIDAY EVENING CONTINUING THROUGH SATURDAY NIGHT. THE STRONGEST
MOTION IS PROGGED SATURDAY NIGHT AND IS OVER THE NORTHERN CWA. THE
LOW LEVEL PRESSURE AND WIND FIELDS POINT TO SOUTHWESTERLY LOW LEVEL
WINDS FRIDAY INTO SATURDAY MORNING. A SURFACE LOW DEVELOPS AND THE
GFS HAS IT OVER EAST CENTRAL COLORADO BY 12Z SUNDAY MORNING. THE
ECMWF HAS IT A BIT EAST OF THERE. THE NAM HAS IT OVER THE NORTHEAST
CORNER OF NEBRASKA AT 12Z SUNDAY MORNING. SO BY SATURDAY NIGHT
MIDNIGHT...THE GFS AND ECMWF HAVE UPSLOPE FOR MOST OF OUR PLAINS...
THE NAM HAS NORTHWESTERLY FLOW DOWN LOW. FOR MOISTURE...IT
INCREASES IN THE MID AND UPPER LEVELS THROUGH THE DAY ON FRIDAY. ON
FRIDAY NIGHT...THE NAM HAS DEEP MOISTURE OVER THE MOUNTAINS...WITH
SOME ALOFT FOR THE PLAINS. THE GFS IS DRIER ALL AROUND. ON
SATURDAY...THE GFS BRINGS MOISTURE IN DURING THE AFTERNOON. THE NAM
HAS MOISTURE PRETTY DEEP OVER THE MOUNTAINS MOST OF THE DAY...WITH
MOISTURE DEEPENING OVER THE WESTERN HALF OF THE PLAINS BY
AFTERNOON. ON SATURDAY NIGHT...THE GFS HAS DEEP MOISTURE OVER THE
WESTERN TWO-THIRDS OF THE CWA...THE NAM HAS IT OVER ALL THE CWA.
THE ECMWF LOOKS QUITE SIMILAR TO THE GFS CONCERNING SATURDAY NIGHT`S
MOISTURE. THE QPF FIELDS HAVE A TAD OF MEASURABLE PRECIPITATION
OVER THE MOUNTAINS FRIDAY AFTERNOON THROUGH SATURDAY MORNING. BY
SATURDAY AFTERNOON...BETTER AMOUNTS ARE PROGGED OVER THE
MOUNTAINS...WITH SMALLER AMOUNTS MOVING OUT ONTO MOST OF THE PLAINS.
ON SATURDAY NIGHT...THE GFS AND ECMWF SHOW QUITE A BULLSEYE OF
MEASURABLE PRECIPITATION OVER THE FOOTHILLS AND ADJACENT PLAINS.
THE NAM HAS THE LION`S SHARE OVER THE CWA`S NORTH-CENTRAL BORDER.
ALL THE MODELS HAVE SNOW FOR THE FOOTHILLS AND SOME OF THE PLAINS
SATURDAY NIGHT. THE WET BULB HEIGHTS ON THE FORECAST SOUNDINGS ALSO
POINT TO THIS BY 03Z SATURDAY EVENING. SO FOR POPS...WILL GO WITH
"CHANCE"S IN THE HIGH MOUNTAINS FROM FRIDAY AFTERNOON THROUGH NOON
SATURDAY. OROGRAPHIC ENHANCEMENT IS NOT EXPECTED...BUT THERE IS
MOISTURE AND SYNOPTIC SCALE ENERGY. WILL UP POPS TO 70-80%S BY
SATURDAY AFTERNOON...CONTINUING THROUGH SATURDAY NIGHT. NO
HIGHLIGHTS RIGHT NOW. FOR THE PLAINS...WILL KEEP IT DRY THROUGH
SATURDAY MORNING. WILL GO WITH 20-30%S SATURDAY AFTERNOON...THEN
"LIKELY"S FOR SATURDAY NIGHT. RIGHT NOW...BELIEVE MORE IN THE
FEATURE LOCATIONS ON THE GFS AND ECMWF. IF THE NAM COMES TRUE...THE
PLAINS WILL HAVE LESS. FOR TEMPERATURES...FRIDAY`S HIGHS ARE 0-1.5
C COOLER THAN TODAY`S EXPECTED READINGS. SATURDAY`S HIGHS COOL OFF
1-6 C...THE LEAST OVER THE NORTHEAST CORNER. FOR THE LATER DAYS...
SUNDAY THROUGH WEDNESDAY...THE UPPER TROUGH/CLOSED LOW MOVES OUT BY
SUNDAY EVENING...WITH NORTHWESTERLY FLOW ALOFT BEHIND IT THROUGH
WEDNESDAY. FOR MOISTURE...THE MOUNTAINS DRY OUT SUNDAY NIGHT INTO
MONDAY MORNING. THEN MOISTURE RETURNS WITH THE NORTHWESTERLY FLOW
ALOFT FOR MUCH OF THE PERIOD...WITH THE DEEPEST PROGGED MONDAY NIGHT
INTO TUESDAY. THE PLAINS LOOK DRY FROM MONDAY THROUGH WEDNESDAY.
TEMPERATURES STAY COOL SUNDAY AND MONDAY...THEN WARM SOMEWHAT
TUESDAY AND AGAIN WEDNESDAY.
AVIATION...MOISTURE LEVELS AT LOW AND MID LEVELS WILL BE DECREASING
TODAY ALLOWING FOR MOSTLY SUNNY SKIES. SOME CIRRUS CLOUDS WILL
BEGIN FILTERING OVERHEAD DURING THE AFTERNOON AND EVENING BUT
CEILINGS...IF ANY...SHOULD REMAIN WELL ABOVE 6000 FEET AGL. WINDS
WILL BE OUT OF THE SOUTH THIS MORNING...BUT THEN SWITCH TO
NORTHWESTERLY IN THE EARLY AFTERNOON AS A LEE TROUGH OF LOW PRESSURE
SHIFTS EAST OF THE AIRPORT. WINDS ARE THEN EXPECTED TO RETURN TO
TYPICAL DRAINAGE PATTERNS THIS EVENING. SHIFTING WIND DIRECTIONS
SHOULD BE ONLY AVIATION IMPACT FOR THE NEXT 24 HOURS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....RJK
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1250 PM EDT THU APR 12 2012
.SYNOPSIS...
SECONDARY LOW PRESSURE SOUTHEAST OF NOVA SCOTIA WILL SLOWLY
TRACK EAST INTO THE OPEN ATLANTIC BY EVENING. HIGH PRESSURE WILL
GRADUALLY BUILD EAST TONIGHT THROUGH FRIDAY. A WARM FRONT WILL
APPROACH FROM THE WEST SATURDAY AND CROSS THE REGION SATURDAY
NIGHT... FOLLOWED BY A COLD FRONT FROM CENTRAL CANADA SUNDAY
NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE: SKIES WILL REMAIN PARTLY TO MOSTLY CLOUDY WITH SOME
SHOWERS ACROSS THE AREA AS THE ATMOSPHERE REMAINS UNSTABLE. PUSHED
SHOWERS JUST A BIT FURTHER NORTH. OTHERWISE, FCST REMAINS THE
SAME.
ORGNL DISC: MOST MODELS INDICATE LITTLE IF ANY SHWRS TO AFFECT
OUR FA TDY...YET LATEST RADAR REF IMAGERY SHOWS ISOLD-SCT SHWRS
OVR E CNTRL AND DOWNEAST PTNS OF THE FA...WITH MORE INTENSE AND
GREATER CVRG OF SHWRS JUST OVR THE BORDER IN NB PROV. HRRR FCST
REF SHOWS THE MORE INTENSE SHWRS WEAKENING BEFORE CROSSING WWRD
INTO E CNTRL AND SE ME THIS MORN...BUT SHOWS ADDITIONAL RN SHWRS
DEVELOPING OVR E CNTRL AND DOWNEAST PTNS OF THE FA THIS AFTN DUE
TO DESTABILIZATION OF THE LOWER ATMOSPHERE UNDER THE EXITING UPPER
LVL LOW. WITH THIS IN MIND...WE BROUGHT SCT SHWRS FURTHER N THIS
MORN INTO ERLY AFTN THAN PREVIOUS UPDATES. FCST LOW VALUES OF
6HRLY QPF THRU THIS EVE WAS BASED ON INCREMENTAL INTERVALS OF POP
VALUES...AND IS RATHER A POTENTIAL OF QPF WITH INDIVIDUAL SHWRS
OVR PARTICULAR LOCATIONS RATHER THAN AN ACTUAL FCST GRADIENT OF
QPF ACROSS THIS PTN OF THE FA.
OTHERWISE...WINDS WILL BE BREEZIER ACROSS THE FA TDY...SPCLY N AND
W WHERE WIND GUSTS UP TO 20 MPH IS XPCTD. HI TEMPS WILL SHOW LESS
N-S GRADIENT THAN TYPICAL THIS TM OF SEASON DUE TO XPCTD GREATER
SUNSHINE POTENTIAL ACROSS THE N BY AFTN. ANY REMAINING SHWRS ERLY
THIS EVE SHOULD DISSIPATE OR MOVE ESE OF DOWNEAST PTNS OF THE FA
BY LATE TNGT. WINDS ACROSS WRN/NRN/CNTRL VLY PTNS OF THE FA COULD
DECOUPLE LATE TNGT UNDER CLRG SKIES...ALLOWING SOME RADIATIONAL
COOLING AND SFC BASED INVSNS RESULTING IN COOLER OVRNGT LOWS OVR
THESE AREAS AS COMPARED TO RECENT PRIOR NGTS
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
HIGH PRESSURE BUILDS FRIDAY WITH A NORTHWESTERLY FLOW. GENERALLY
SUNNY SKIES ARE EXPECTED ACROSS THE FORECAST AREA WITH JUST
SCATTERED THIN CUMULUS AND SOME AFTERNOON CIRRUS. HIGHS SHOULD
REACH THE LOW 50S NORTH AND UPPER 50S DOWN EAST WITH LOW HUMIDITY.
TEMPERATURES WILL CONTINUE TO MODERATE SATURDAY WITH WARM AIR
ADVECTION AND WINDS BACKING TO A MORE WEST TO SOUTHWEST FLOW.
HIGHS WILL REACH THE UPPER 50S NORTH AND LOW 60S DOWN EAST. CLOUDS
WILL INCREASE DURING THE AFTERNOON AS A WEAK WARM FRONT APPROACHES
FROM QUEBEC.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
SOME LIGHT RAIN IS POSSIBLE SATURDAY NIGHT AS A WARM FRONT CROSSES
THE FORECAST AREA. THE FRONT WILL HAVE MOVED OUT OF THE AREA BY
SUNDAY MORNING AND SHOULD SET THE STAGE FOR A WARM AND WINDY DAY
WITH HIGHS REACHING NEAR 60F NORTH AND MID TO UPPER 60S DOWN
EAST...EXCEPT NEAR THE COAST WHERE AN ONSHORE FLOW WILL LIMIT
HIGHS TO THE 50S. SUNSHINE WILL BE SOMEWHAT LIMITED...ESPECIALLY
TOWARDS THE CROWN OF MAINE AS A STRONG COLD FRONT WILL APPROACH
THE THE SJV DURING THE AFTERNOON AND MOVE SOUTH ACROSS THE
FORECAST AREA SUNDAY AFTERNOON AND EVENING. THIS FRONT COULD
PRODUCE SOME LOW-TOPPED CONVECTION BRINGING STRONG GUSTY WINDS TO
THE SURFACE OVER 30 KTS. WITH THE FRONT THROUGH THE AREA...A SUNNY
AND WINDY DAY FOLLOWS FOR MONDAY. THE BIGGEST QUESTION WILL BE THE
EXTENT OF THE COLD AIR ADVECTION AND STRENGTH OF WINDS. ONE
SCENARIO WOULD PRODUCE HIGHS IN THE LOW 50S NORTH AND ANOTHER DAY
IN THE MID 60S DOWN EAST. THE OTHER END OF THE SPECTRUM ONLY GIVES
HIGHS NEAR 40F IN THE CROWN OF MAINE AND LOW 50S DOWN EAST. AM
FAVORING A BLEND BETWEEN THESE WITH HIGHS IN THE MID 40S NORTH AND
MID 50S DOWN EAST. EITHER WAY...THIS IS A DRY AIR MASS AND
TEMPERATURES SHOULD COOL INTO THE LOW-MID 20S NORTH AND LOW 30S
DOWN EAST ON MONDAY NIGHT.
THE REMAINDER OF THE PERIOD WILL BE CLOUDY...COOL AND WET AS LOW
PRESSURE MOVES SLOWLY FROM THE GREAT LAKES REGION TOWARDS THE NEW
ENGLAND. THE BIGGEST QUESTION WILL BE WHETHER IT WILL BE COLD
ENOUGH TO SUPPORT SNOW IN NORTHERN ZONES TUESDAY MORNING. THIS
WILL DEPEND ON THE AMOUNT OF COLD AIR ADVECTION BEHIND THE COLD
FRONT SUNDAY NIGHT. WILL GO WITH A CHANCE OF SNOW FOR ZONES 1
THROUGH 6 TUESDAY MORNING.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
NEAR TERM: MAINLY LOW TO MID VFR...WITH A BRIEF PD OF MVFR
POSSIBLE ERLY TO MID MORN...SPCLY DOWNEAST SITES WITH ANY SHWRS.
CLDS SHOULD CLR FROM ALL TAF SITES NW TO SE OVRNGT.
SHORT TERM: VFR. CHANCE OF IFR IN AN AFTERNOON OR EVENING RAIN
SHOWER SUNDAY...ACCOMPANIED BY WEST WINDS GUSTING OVER 30 KTS.
&&
.MARINE...
NEAR TERM: NO HDLNS ANTICIPATED THRU TNGT...WITH NW WINDS OF 10 TO
20 KT DIMINISHING LATE TDY THRU TNGT. WE USED A BLEND OF 00Z NAM12...
GFS40 AND GMOS FOR WINDS AND A 50%/30%/20% WW3/SWAN-NAM/SWAN-GFS
FOR WV HTS.
SHORT TERM: GENERALLY BENIGN CONDITIONS EXCEPT A POSSIBLE SCA
SUNDAY AHEAD OF A COLD FRONT. WAVE HTS OVER 5 FEET ARE MORE LIKELY
TO PRODUCE AN SCA DURING THIS PERIOD RATHER THAN WINDS OVER 25 KTS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...VJN
SHORT TERM...MCW
LONG TERM...MCW
AVIATION...VJN
MARINE...VJN/MCW
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1208 PM EDT THU APR 12 2012
.SYNOPSIS...
SECONDARY LOW PRESSURE SOUTHEAST OF NOVA SCOTIA WILL SLOWLY
TRACK EAST INTO THE OPEN ATLANTIC BY EVENING. HIGH PRESSURE WILL
GRADUALLY BUILD EAST TONIGHT THROUGH FRIDAY. A WARM FRONT WILL
APPROACH FROM THE WEST SATURDAY AND CROSS THE REGION SATURDAY
NIGHT... FOLLOWED BY A COLD FRONT FROM CENTRAL CANADA SUNDAY
NIGHT.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE: SKIES WILL REMAIN PARTLY TO MOSTLY CLOUDY WITH SOME
SHOWERS ACROSS THE AREA AS THE ATMOSPHERE REMAINS UNSTABLE. PUSHED
SHOWERS JUST A BIT FURTHER NORTH. OTHERWISE, FCST REMAINS THE
SAME.
OTHERWISE...WE MODIFIED FCST LOWS BASED ON LATEST 10Z OBSVD SFC
TEMPS...WITH MOST OF THIS OCCURRING OVR ERN PTNS OF THE FA DUE TO
WARMER THAN ANTICIPATED OBS COMPARED TO FCST LOWS COMPARED TO THIS
PTN OF THE FCST AREA. WRN VLYS DID COOL TO MID TO UPPER 20S...SO
VIRTUALLY NO CHG WAS MADE TO LOW TEMPS THERE. BY MAKING THESE LATE
ADJUSTMENTS...WE ARE ABLE TO MERGE TO FCST HI TEMPS THIS AFTN AND
PRODUCE A MORE REALISTIC RISING TEMP CURVE FOR THIS MORN.
ORGNL DISC: MOST MODELS INDICATE LITTLE IF ANY SHWRS TO AFFECT
OUR FA TDY...YET LATEST RADAR REF IMAGERY SHOWS ISOLD-SCT SHWRS
OVR E CNTRL AND DOWNEAST PTNS OF THE FA...WITH MORE INTENSE AND
GREATER CVRG OF SHWRS JUST OVR THE BORDER IN NB PROV. HRRR FCST
REF SHOWS THE MORE INTENSE SHWRS WEAKENING BEFORE CROSSING WWRD
INTO E CNTRL AND SE ME THIS MORN...BUT SHOWS ADDITIONAL RN SHWRS
DEVELOPING OVR E CNTRL AND DOWNEAST PTNS OF THE FA THIS AFTN DUE
TO DESTABILIZATION OF THE LOWER ATMOSPHERE UNDER THE EXITING UPPER
LVL LOW. WITH THIS IN MIND...WE BROUGHT SCT SHWRS FURTHER N THIS
MORN INTO ERLY AFTN THAN PREVIOUS UPDATES. FCST LOW VALUES OF
6HRLY QPF THRU THIS EVE WAS BASED ON INCREMENTAL INTERVALS OF POP
VALUES...AND IS RATHER A POTENTIAL OF QPF WITH INDIVIDUAL SHWRS
OVR PARTICULAR LOCATIONS RATHER THAN AN ACTUAL FCST GRADIENT OF
QPF ACROSS THIS PTN OF THE FA.
OTHERWISE...WINDS WILL BE BREEZIER ACROSS THE FA TDY...SPCLY N AND
W WHERE WIND GUSTS UP TO 20 MPH IS XPCTD. HI TEMPS WILL SHOW LESS
N-S GRADIENT THAN TYPICAL THIS TM OF SEASON DUE TO XPCTD GREATER
SUNSHINE POTENTIAL ACROSS THE N BY AFTN. ANY REMAINING SHWRS ERLY
THIS EVE SHOULD DISSIPATE OR MOVE ESE OF DOWNEAST PTNS OF THE FA
BY LATE TNGT. WINDS ACROSS WRN/NRN/CNTRL VLY PTNS OF THE FA COULD
DECOUPLE LATE TNGT UNDER CLRG SKIES...ALLOWING SOME RADIATIONAL
COOLING AND SFC BASED INVSNS RESULTING IN COOLER OVRNGT LOWS OVR
THESE AREAS AS COMPARED TO RECENT PRIOR NGTS
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY/...
HIGH PRESSURE BUILDS FRIDAY WITH A NORTHWESTERLY FLOW. GENERALLY
SUNNY SKIES ARE EXPECTED ACROSS THE FORECAST AREA WITH JUST
SCATTERED THIN CUMULUS AND SOME AFTERNOON CIRRUS. HIGHS SHOULD
REACH THE LOW 50S NORTH AND UPPER 50S DOWN EAST WITH LOW HUMIDITY.
TEMPERATURES WILL CONTINUE TO MODERATE SATURDAY WITH WARM AIR
ADVECTION AND WINDS BACKING TO A MORE WEST TO SOUTHWEST FLOW.
HIGHS WILL REACH THE UPPER 50S NORTH AND LOW 60S DOWN EAST. CLOUDS
WILL INCREASE DURING THE AFTERNOON AS A WEAK WARM FRONT APPROACHES
FROM QUEBEC.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
SOME LIGHT RAIN IS POSSIBLE SATURDAY NIGHT AS A WARM FRONT CROSSES
THE FORECAST AREA. THE FRONT WILL HAVE MOVED OUT OF THE AREA BY
SUNDAY MORNING AND SHOULD SET THE STAGE FOR A WARM AND WINDY DAY
WITH HIGHS REACHING NEAR 60F NORTH AND MID TO UPPER 60S DOWN
EAST...EXCEPT NEAR THE COAST WHERE AN ONSHORE FLOW WILL LIMIT
HIGHS TO THE 50S. SUNSHINE WILL BE SOMEWHAT LIMITED...ESPECIALLY
TOWARDS THE CROWN OF MAINE AS A STRONG COLD FRONT WILL APPROACH
THE THE SJV DURING THE AFTERNOON AND MOVE SOUTH ACROSS THE
FORECAST AREA SUNDAY AFTERNOON AND EVENING. THIS FRONT COULD
PRODUCE SOME LOW-TOPPED CONVECTION BRINGING STRONG GUSTY WINDS TO
THE SURFACE OVER 30 KTS. WITH THE FRONT THROUGH THE AREA...A SUNNY
AND WINDY DAY FOLLOWS FOR MONDAY. THE BIGGEST QUESTION WILL BE THE
EXTENT OF THE COLD AIR ADVECTION AND STRENGTH OF WINDS. ONE
SCENARIO WOULD PRODUCE HIGHS IN THE LOW 50S NORTH AND ANOTHER DAY
IN THE MID 60S DOWN EAST. THE OTHER END OF THE SPECTRUM ONLY GIVES
HIGHS NEAR 40F IN THE CROWN OF MAINE AND LOW 50S DOWN EAST. AM
FAVORING A BLEND BETWEEN THESE WITH HIGHS IN THE MID 40S NORTH AND
MID 50S DOWN EAST. EITHER WAY...THIS IS A DRY AIR MASS AND
TEMPERATURES SHOULD COOL INTO THE LOW-MID 20S NORTH AND LOW 30S
DOWN EAST ON MONDAY NIGHT.
THE REMAINDER OF THE PERIOD WILL BE CLOUDY...COOL AND WET AS LOW
PRESSURE MOVES SLOWLY FROM THE GREAT LAKES REGION TOWARDS THE NEW
ENGLAND. THE BIGGEST QUESTION WILL BE WHETHER IT WILL BE COLD
ENOUGH TO SUPPORT SNOW IN NORTHERN ZONES TUESDAY MORNING. THIS
WILL DEPEND ON THE AMOUNT OF COLD AIR ADVECTION BEHIND THE COLD
FRONT SUNDAY NIGHT. WILL GO WITH A CHANCE OF SNOW FOR ZONES 1
THROUGH 6 TUESDAY MORNING.
&&
.AVIATION /16Z THURSDAY THROUGH MONDAY/...
NEAR TERM: MAINLY LOW TO MID VFR...WITH A BRIEF PD OF MVFR
POSSIBLE ERLY TO MID MORN...SPCLY DOWNEAST SITES WITH ANY SHWRS.
CLDS SHOULD CLR FROM ALL TAF SITES NW TO SE OVRNGT.
SHORT TERM: VFR. CHANCE OF IFR IN AN AFTERNOON OR EVENING RAIN
SHOWER SUNDAY...ACCOMPANIED BY WEST WINDS GUSTING OVER 30 KTS.
&&
.MARINE...
NEAR TERM: NO HDLNS ANTICIPATED THRU TNGT...WITH NW WINDS OF 10 TO
20 KT DIMINISHING LATE TDY THRU TNGT. WE USED A BLEND OF 00Z NAM12...
GFS40 AND GMOS FOR WINDS AND A 50%/30%/20% WW3/SWAN-NAM/SWAN-GFS
FOR WV HTS.
SHORT TERM: GENERALLY BENIGN CONDITIONS EXCEPT A POSSIBLE SCA
SUNDAY AHEAD OF A COLD FRONT. WAVE HTS OVER 5 FEET ARE MORE LIKELY
TO PRODUCE AN SCA DURING THIS PERIOD RATHER THAN WINDS OVER 25 KTS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...MCB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
132 PM EDT THU APR 12 2012
.SYNOPSIS...
ISSUED AT 426 AM EDT THU APR 12 2012
WV IMAGERY AND RUC ANALYSIS INDICATED AN AMPLIFIED PATTERN WITH A
MID/UPPER LEVEL TROUGH INTO THE WRN CONUS A RIDGE OVER THE PLAINS
AND A TROUGH OVER THE EAST RESULTING IN NW FLOW THROUGH THE NRN
GREAT LAKES. A WELL-DEFINED UPSTREAM SHORTWAVE TROUGH WAS LOCATED
OVER NRN ONTARIO NEAR CYPL. AT THE SFC...A RIDGE EXTENDED FROM JAMES
BAY THROUGH THE WRN GREAT LAKES LEAVING CLEAR SKIES...LIGHT WINDS
OVER UPPER MI AND SEASONABLY COOL TEMPS IN THE DRY AIRMASS.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY NIGHT)
ISSUED AT 426 AM EDT THU APR 12 2012
TODAY...SINCE A VERY DRY AIRMASS DOMINATED THE REGION...PER 00Z
CYPL/KAPX/KGRB SOUNDINGS ONLY MID/HIGH CLOUDS WERE ASSOCIATED WITH
THE NRN ONTARIO SHRTWV. SIMILARLY...AS THE SHRTWV MOVES THROUGH LAKE
SUPERIOR AND ERN UPPER MI...ONLY MID CLOUDS ARE EXPECTED DESPITE
MODERATE 700-300 MB QVECTOR CONV. WITH A DECENT AMOUNT OF
SUNSHINE...TEMPS SHOULD CLIMB INTO THE MID AND UPPER 50S INLAND
WEST. THE WEAK PRESSURE GRADIENT WILL ALLOW LAKE BREEZES TO
DEVELOP...KEEPING READINGS AOB 50 ALONG THE GREAT LAKES. AFTERNOON
MIXING SHOULD ALSO DROP DEWPOINTS TO AROUND 20 WITH RH AOB 25 PCT
INLAND WEST.
TONIGHT...TEMPS WILL AGAIN DROP BELOW FREEZING IN MOST LOCATIONS AS
LIGHT WINDS PREVAIL AND HIGH CLOUDS ONLY MOVE INTO THE WEST LATE.
SLIGHTLY HIGHER TEMPS ARE EXPECTED WITH DOWNSLOPE SE FLOW WEST NEAR
LAKE SUPERIOR.
FRIDAY INTO FRIDAY NIGHT...MODELS SUGGEST THAT THE TROUGH WILL
ADVANCE TO THE EAST AS A SHORTWAVE LIFTS NE FROM THE PLAINS THROUGH
MN INTO NRN ONTARIO AND THE NRN LAKES. A BAND OF WAA/ISENTROPIC LIFT
ALONG WITH FAVORABLE MOISTURE TRANSPORT SHOULD PRODUCE SCT/NMRS
SHRA MOVING INTO THE WEST LATE FRIDAY AND ACROSS THE CWA FRIDAY
NIGHT. THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE TIMING OF
PCPN MOVING INTO THE AREA. SINCE THE DYNAMICS MOVE THROUGH FAIRLY
QUICKLY...ONLY MODEST PCPN AMOUNTS IN THE 0.10-0.20 INCH RANGE ARE
EXPECTED. WITH ELEVATED CAPE REMAINING SOUTH OF THE AREA...PER
NAM/GFS...NO TSRA ARE EXPECTED.
.LONG TERM...(SATURDAY THROUGH WEDNESDAY)
ISSUED AT 426 AM EDT THU APR 12 2012
H925-700 WAA AHEAD OF THE WARM FRONT WILL BE PUSHING NE ACROSS NE
LAKE SUPERIOR AT THE START OF THE PERIOD...WHILE DRY SLOT WORKS OVER
THE REST OF THE CWA DURING THE MORNING HOURS. LLVL MOISTURE LINGERS
IN THE MORNING AND QUICKLY DIMINISHES IN THE AFTN...SO HAVE LOWERED
TO PARTLY CLOUDY IN THE AFTN AHEAD OF NEXT WAVE AND APPROACHING COLD
FRONT FROM THE NW ON SAT NIGHT. AS A RESULT...HAVE DIMINISHED POPS
FROM W TO E DURING THE MORNING HRS AND REMOVED THEM COMPLETELY FOR
THE AFTN. COULD END UP BEING A WARM DAY ON SAT. MIXING TO H925-900
WITH THE DECREASING CLOUDS AND SSW WINDS WOULD LEAD TO HIGHS IN THE
60S TO LOWER 70S. LIKE THE PREVIOUS SHIFT...MADE ANOTHER JUMP IN THE
TEMPS /3-7 DEGREES/ FOR SAT OVER THE WRN TWO THIRDS. THIS COULD EVEN
BE A FEW DEGREES TOO LOW IF THE CLOUDS REALLY CLEAR OUT IN THE AFTN
AND THE WINDS ARE STRONG ENOUGH TO LIMIT LK BREEZES NEAR LK
SUPERIOR.
COLD FRONT ASSOCIATED WITH THE LOW THAT PUSHED THROUGH ONTARIO ON
SAT WILL MOVE SE ACROSS UPPER MI ON SAT NIGHT. THE TIMING OF THIS
FRONT AND A SHORTWAVE/LOW MOVING UP FRONT WILL DETERMINE PCPN
CHANCES FOR SAT NIGHT. WITH THE WAY THE MODELS HAVE BEEN FOR THIS
UPCOMING WEEKEND...LIMITED CONFIDENCE ON PCPN CHANCES BUT CHANCES
OVER THE SRN HALF OF THE CWA SEEM REASONABLE AT THIS POINT. THIS
FRONT SHOULD SLIDE FARTHER SE AND CONTINUE TO DIMINISH PCPN CHANCES
ON SUN.
UNCERTAINTY CONTINUES FARTHER OUT INTO THE FORECAST WITH THE SW FLOW
ALOFT FROM THE UPPER TROUGH OVER THE WRN CONUS. MODELS TRADITIONALLY
HAVE A DIFFICULT TIMING WITH THESE SITUATIONS DUE TO SHORTWAVES OVER
THE PACIFIC HAVING TO ROTATE THROUGH THE UPPER TROUGH AND THE LAST
COUPLE OF DAYS OF RUNS HAVE BEEN NO DIFFERENT.
00Z GEM/GFS/ECMWF COMING INTO BETTER AGREEMENT WITH A LOW PUSHING
OUT OF THE CNTRL/SRN PLAINS ON SUN NIGHT AND INTO THE LOWER GREAT
LKS ON MON AFTN/NIGHT. STILL DIFFERENCES ON THE TIMING/TRACK...BUT
STARTING TO GET A BETTER FEEL ON THIS SYSTEM. THIS WOULD BRING AN
INITIAL SURGE OF WAA PCPN TO THE AREA LATE SUN NIGHT AND INTO MON
/24HRS EARLIER THAN YESTERDAY/...BEFORE THE PCPN REFOCUSES FARTHER
SE AND CLOSER TO THE LOW AND UPPER ENERGY. COLD AIR BEHIND THE COLD
FRONT ON SAT NIGHT AND SUN WILL LEAVE A COLD NEAR SFC LAYER.
ALOFT...HINTS AT A NOSE OF 1C TEMPS BETWEEN H850-700 BUT LIKELY
WON/T BE ENOUGH TO ENTIRELY MELT THE SNOW. WITH THE UNCERTAINTY IN
THE MODELS...FOLLOWED THE MODEL CONSENSUS ON THE 1000-850/850-700
THICKNESS PATTERN AND USED THAT FOR PCPN TYPE. THIS PRODUCES A
RAIN/SNOW MIX WHERE THAT WARM AIR NOSE IS OVER THE FAR SE PART OF
THE CWA AND SNOW ELSEWHERE. MODEL QPF SHOWS THE POTENTIAL FOR
MEASURABLE/ADVISORY SNOW OVER THE WRN CWA ON MON...SO WILL BE
INTERESTING IF THAT CONTINUES ON FUTURE RUNS.
00Z GFS/GEM HOLDING ON TO THE PCPN OVER THE SE HALF OF THE CWA ON
TUES...AS ISENTROPIC ASCENT CONTINUES AROUND THE H850 LOW CENTERED
OVER NRN LK MI. 12Z ECMWF HAS ALREADY MOVED THE HIGH PRESSURE RIDGE
IN BY THIS TIME...SO WILL CONTINUE TO MENTION CHANCES MAINLY OVER
THE SE HALF OF THE CWA. THEN WILL SHOW A DIMINISHING TREND IN PCPN
ON TUES NIGHT AND WED. RIGHT NOW...00Z GFS SHOWING HIGH PRESSURE
RIDGE MOVING OVER THE AREA AT THAT TIME. 12Z ECMWF IS FASTER WITH AN
APPROACHING COLD FRONT AND MOVES IT THROUGH ON WED MORNING BUT THE
00Z RUN BACKED OFF ON THAT POTENTIAL. WILL GO WITH A MAINLY DRY
FORECAST FOR WED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 129 PM EDT THU APR 12 2012
EXPECT VFR CONDITIONS THROUGH FRIDAY MORNING AS HIGH PRESSURE STAYS
IN CONTROL OF WEATHER OVR UPR MICHIGAN. MID CLOUDS THICKEN ON FRIDAY
AFTERNOON WITH SCATTERED RAIN SHOWERS ARRIVING BY FRIDAY EVENING. &&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 426 AM EDT THU APR 12 2012
HIGH PRESSURE WILL COVER THE UPPER GREAT LAKES REGION TODAY AND
TONIGHT...LEADING TO WINDS BELOW 20KTS. A LOW PRESSURE SYSTEM
TAKING SHAPE OVER THE GREAT PLAINS WILL MOVE NORTHEAST ON FRIDAY
AND INTO ONTARIO ON SAT. WINDS WILL SHIFT TO THE SE...BUT THE
MARINE LAYER SHOULD KEEP WINDS FROM EXCEEDING 20KTS. THIS MARINE
LAYER WILL REMAIN IN PLACE UNTIL A COLD FRONT MOVES THROUGH ON
SATURDAY NIGHT. THIS WILL SHIFT THE WINDS TO THE NW UP TO 25KTS ON
SUN.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLA
MARINE...SRF
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
431 PM CDT THU APR 12 2012
.DISCUSSION...
Short Range (Tonight-Saturday)...
A large upper trough will continue to carve out space over the
western half of the U.S. Periodic shortwave energy will eject from
the base of the trough and combine with increasing moisture and
instability to generate several rounds of strong to severe
thunderstorms across KS/MO and areas to the southwest.
In the near term, a shortwave/vorticity max combo tracking ene
through eastern KS has generated several bands of elevated
convection. Short range convective models such as the HRRR handled
the associated convection/qpf best. Other models underplayed it
although they did a reasonably good job with the h5 vorticity
fields. Activity expected to gradually diminish as it pushes through
the upper level ridge and into drier downstream airmass.
Rest of forecast concerns center on how convective development will
be affected by the elevated mixed layer(EML) that is expected to
overspread the region tomorrow and Saturday. Lacking much of a
boundary to focus on believe this EML will prove to inhibit much of
the daytime convection on Friday and Saturday. Instead will focus on
the regeneration of the southerly low level jet over the Central
Plains both nights as the primary mechanism to initiate and maintain
nighttime convection. The first occurrence will be tonight and favor
using the 12z 4km NMM-WRF for tonights activity. An MCS is expected
to form over central/eastern NE/KS by mid evening and then roll
eastward as the low level jet veers to the southwest. The veering
allows the activity to maintain itself vs running ahead of the main
moisture source. Raised late night pops to categorical most areas.
Convection likely ongoing Friday morning but with it ending from
west to east as the EML begins to work in from the west. Conceptual
model then favors minimal if any convection so have toned down pops
for the rest of Friday/early Friday evening. Upstream redevelopment
convection may need the arrival of another shortwave and reformation
of the low level jet Friday evening. So, will again concentrate
highest pops for Friday night. Max temperatures will be tricky as
they will be greatly affected any residual cloud cover. Northeast MO
will likely be the coolest region.
Saturday should be similar to Friday in that the EML will be in
place and thus inhibit most of the convection. By Saturday a better
dryline may be in place over central KS and as a 110kt swly upper
level jet interacts with a 40kt+ southerly low level jet, expect a
squall-line of severe storms to erupt and advance eastward Saturday
evening. Severe weather could impact the western portion of the CWA
Saturday evening before it weakens. Inspection of NAM BUFR soundings
suggests that if clouds can break up many locations could challenge
the 80 degree mark.
MJ
Medium Range (Sunday through Thursday)...
Sunday...The main wave, in the form a closed upper low, associated
with the broad western CONUS trough will move into the Central
Plains. This will force a cold front into the area late in the day
on Sunday. There is much uncertainty as far as the potential for
severe weather due to ongoing showers that may be persisting across
the area in the morning and the residual cloud cover. 12Z NAM/GFS
Bufr soundings are showing only weak instability however if skies
clear, conditions could destabilize quickly with storms firing along
the cold front or along any remnant outflow boundaries from earlier
convection. This will need to be monitored further for severe
potential. Outside of the severe potential...flooding may also
become a concern over some locations as PWAT values on Sunday are
ranging from 1"-1.5". With periods of rainfall...possibly heavy in
some locations, expected Thursday night through Sunday morning and
additional heavy rain may lead to localized flooding as well as
flooding of small streams and creeks.
Monday - Thursday...We will see a pattern change as we move into the
beginning of next week. The amplified pattern that brought us
showers and thunderstorms through the weekend will become zonal
and thus tranquil. Temperatures on Monday and Tuesday will be
slightly below average with highs ranging from the mid 50s to mid
60s. Wednesday will feature a return to southerly flow out ahead of
a weak cold front. Temperatures will move to near normal with highs
in the 60s however that will be the next chance for showers across
the area as the cold front moves through the late Wednesday into
Wednesday night. By Thursday, high pressure moves back into the area
with highs moving above normal into the upper 60s to mid 70s.
73
&&
.AVIATION...
For the 18Z TAFs...Scattered showers with low-end VFR cigs will be
moving through the terminals between now and 21z. An isolated
lightning strike or two is possible. A much better chance for
showers and isolated thunderstorms will arrive at all 3 terminals
late this afternoon. Cigs could drop into the MVFR category with
these showers. Should see a break in the rain during the evening
hours but a larger complex of showers and thunderstorms is expected
to form over far eastern KS late this evening and affect all 3
terminals again from midnight on. This complex should be east of the
terminals shortly after sunrise Friday. MVFR cigs are likely from
late tonight through the rest of the forecast period.
Southeasterly winds will gradually pick up with winds becoming gusty
late tonight as the low level jet cranks up. In addition, BUFR
soundings indicate a low level inversion will set up when these
winds become gusty. Low-level wind shear conditions are expected
late tonight as the winds at the low-level inversion veer quickly to
the ssw and increase markedly. The low-level wind shear conditions
will end as the inversion dissipates shortly after sunrise.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS GLASGOW MT
1005 AM MDT THU APR 12 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH SATURDAY...
UPDATED THE FORECAST TO ADJUST THE TEMPERATURES SLIGHTLY AND LOWER
POPS ACROSS THE EAST. THE HRRR MODELS IS SHOWING A DRY SLOT ACROSS
MOST OF THE EASTERN ZONES TODAY. QPF IS MOSTLY CONFINED TO THE
WESTERN ZONES. DRY SLOT ALREADY EVIDENT ON THE WATER VAPOR
SATELLITE LOOP OVER SOUTHERN MONTANA. THIS MEANS MOST IF NOT ALL
WETTING RAIN WILL OCCUR OVER PETROLEUM...WESTERN GARFIELD AND
PHILLIPS COUNTIES. THIS IS THE AREA THAT CAN EXPECT BETWEEN ONE
TENTH AND THREE TENTH OF AN INCH. THERE IS STILL A CHANCE OF
SHOWERS ACROSS THE EASTERN ZONES THIS AFTERNOON BUT THE CHANCES OF
RECEIVING A WETTING RAIN IS EXTREMELY LOW. THE YELLOWSTONE VALLEY
MAY EVEN SEE SOME ISOLATED THUNDERSTORMS LATER INT HE AFTERNOON.
RSMITH
PREVIOUS DISCUSSION...THE NARROW UPPER LEVEL RIDGE SHIFTS EAST OF
MONTANA TODAY AS AN EASTERN PACIFIC LONG WAVE TROUGH BEGINS TO
MOVE OVER THE WESTERN STATES. AN ASSOCIATED COLD FRONT AND
OVERRUNNING MOISTURE DRAWN NORTH FROM THE BASE OF THE TROUGH NEAR
BAJA WILL INITIATE RAIN SHOWERS TODAY. AS THE CLOSED OFF LEE
SURFACE TROUGH SHIFTS FROM CENTRAL TO EASTERN MONTANA...WINDS WILL
SHIFT FROM THE EAST TO THE WEST TODAY. THE ON-GOING LWA FOR FORT
PECK LAKE WILL BE EXTENDED THROUGH THE DAY UNTIL 9 PM THIS
EVENING. ALTHOUGH THERE WILL BE A WIND SHIFT AT WHICH TIME THE
WINDS WILL LOWER...AFTERNOON WINDS SHIFTING AROUND TO THE WEST
WILL RAMP BACK UP. WINDS ALOFT OF 40 KTS COULD PRODUCE QUITE A BIT
OF GUSTINESS IF BROUGHT TO THE SURFACE BY PRECIPITATION. THE FOCUS
OF THE STORM DYNAMICS APPEARS TO BE MOSTLY IN THE WESTERN COUNTIES
AND ESPECIALLY NORTH OF THE INTERNATIONAL BORDER. THE MAXIMUM
LOCAL QPF POTENTIAL AMOUNTS WILL RANGE FROM 0.15 INCH TO A THIRD
OF AN INCH...DEPENDING ON MODEL. MODELS HAVE BEEN OVER-DOING QPF
LATELY SO WILL TREND TO A LOWER BLEND. PRECIPITATION DROPS OFF BY
EVENING AS THE SURFACE LOW MOVES TOTALLY NORTH AND THE COLD FRONT
MOVES EAST INTO THE DAKOTAS. WITH MODELS KEEPING QPF ALL AROUND
NORTHEAST MONTANA...WILL KEEP SLIGHT CHANCE TO LOW CHANCE POPS
GOING TONIGHT. A RELAXED SURFACE GRADIENT WILL DIMINISH EVENING
WINDS. THICKNESS HEIGHTS DO NOT DROP OFF MUCH SO MAXIMUM
TEMPERATURES WILL BE SEASONAL OR SLIGHTLY ABOVE NORMAL.
AGAIN...MODEL GUIDANCE IS HAVING DIFFICULTY WITH THE DETAILS OF
THIS SYSTEM. THE INCREASED SKY COVER WILL MAKE CONDITIONS FEEL
COOLER.
FRIDAY AND SATURDAY...THE LONG WAVE TROUGH MOVES OVER THE ENTIRE
WEST WHICH WILL CONTINUE SENDING WINDS ALOFT FROM THE SOUTH OVER
NEMONT. A SECONDARY LOW PRESSURE LOBE DEVELOPS IN NORTH DAKOTA
THAT COULD SEND WRAP-AROUND SHOWERS INTO OUR EASTERN ZONES BEFORE
THE LOW SHIFTS FARTHER EAST FRIDAY NIGHT. BUT IN GENERAL NEMONT
WILL BE SOMEWHAT DRY-SLOTTED. SO WILL KEEP POPS IN THE SLIGHT
CHANCE CATEGORY. THICKNESS HEIGHTS DO NOT CHANGE MUCH SO EXPECT
TEMPERATURES NOT TO DEVIATE MUCH FROM THOSE TODAY. SCT
.LONG TERM...SATURDAY NIGHT THROUGH THURSDAY...
SATURDAY NIGHT INTO SUNDAY...NORTHEAST MONTANA WILL BE IN THE
DRIER AND WEAKER NORTHERN STREAM UPPER TROUGH IN A SPLIT FLOW
ALOFT. STRONGER AND WETTER SOUTHERN STREAM WILL STAY WELL SOUTH.
COULD STILL SEE A FEW RAIN POSSIBLY SNOW SHOWERS SATURDAY NIGHT
AND INTO SUNDAY IN THE SOUTH.
HIGH PRESSURE SYSTEM BUILDS INTO MONTANA AND NORTH DAKOTA ON
SUNDAY FROM CANADA. THE NORTH SHOULD BE DRY ON SUNDAY WITH THE
ENTIRE AREA DRYING OUT BY SUNDAY NIGHT.
SHORTWAVE RIDGE WILL GIVE THE AREA DRY WEATHER ON MONDAY AND
MONDAY NIGHT WITH A WARMING TREND THROUGH TUESDAY. THE NEXT
SHORTWAVE TROUGH MOVES THROUGH TUESDAY AFTERNOON AND EVENING WITH
A FRONTAL SYSTEM THAT MAY HAVE ENOUGH MOISTURE FOR A FEW SHOWERS.
WILL MENTION A SLIGHT CHANCE FOR NOW. THE FLOW BECOMES MORE ZONAL
ALOFT BY MID WEEK WITH A FAST MOVING SHORTWAVE RIDGE ON WEDNESDAY
FOLLOWED BY ANOTHER TROUGH ON THURSDAY. WITH SOME RUN TO RUN
TIMING DIFFERENCE...OPTED TO BROAD BRUSH SLIGHT CHANCE POPS FOR
NOW. FORRESTER
&&
.AVIATION...
VFR. A LOW PRESSURE SYSTEM NEAR BILLINGS AND A FRONTAL BOUNDARY
OVER CENTRAL MONTANA WILL KEEP EAST TO SOUTHEAST WINDS OVER THE
TAF SITES INTO THIS MORNING. KGGW WILL SEE THE STRONGEST EAST
WINDS DUE TO THE LOCAL EFFECTS OF THE MILK RIVER VALLEY. THE FRONT
AND LOW PRESSURE SYSTEM WILL MOVE NORTHEAST ACROSS THE REGION
TODAY. THE WINDS WILL TURN TO THE WEST BEHIND THE FRONT THIS
AFTERNOON. CLOUDS WILL CONTINUE TO INCREASE AND LOWER THIS MORNING
AS THE FRONT PUSHES EAST WITH SOME SHOWERS POSSIBLE THROUGH THIS
AFTERNOON OR EARLY EVENING. LOOK FOR SKIES TO BECOME PARTLY CLOUDY
AFTER MIDNIGHT WITH SCATTERED MID OR HIGH LEVEL CLOUDS.
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR FOR FORT PECK
LAKE IN THE FORT PECK LAKE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
237 PM CDT THU APR 12 2012
.DISCUSSION.../ISSUED AT 957 AM CDT/
MAIN UPDATES TO THE FORECAST WERE TO BRING SCATTERED SHOWERS AND
THUNDERSTORMS INTO THE EASTERN HALF OF THE REGION A BIT EARLIER
THIS MORNING...AND TO LOWER AFTERNOON CHANCES A BIT AS SHOWERS
LOOK TO BE WIDELY SCATTERED. MODELS DO NOT HAVE A GOOD HANDLE ON
THIS AFTERNOON...WITH THE HRRR BROAD BRUSHING THE ENTIRE AREA WITH
PRECIPITATION UNTIL 00Z...AND OTHER MODELS NOT CAPTURING CURRENT
RAINFALL AND HOLDING OFF WITH ANY ACCUMULATION UNTIL THIS EVENING.
CURRENTLY...FEEL AS THOUGH THERE WILL BE A BREAK STARTING IN THE
EARLY AFTERNOON AFTER THE MIDLEVEL WAVE MOVES THROUGH...THEN HEAVIER
PRECIPITATION STARTING UP AHEAD OF THE FRONT THIS EVENING. WILL PLAN
TO KEEP AN EYE ON PRECIPITATION TRENDS TO THE SOUTHWEST AND FUTURE
HRRR RUNS IF THEY BECOME AVAILABLE...AND WILL CONTINUE TO UPDATE
THIS MORNING AS NEEDED. /LAFLIN
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
SCATTERED SHOWERS WILL CONTINUE TO LIFT NORTHEAST ACROSS FAR
SOUTHEAST SOUTH DAKOTA...AND INTO NORTHWEST IOWA AND SOUTHWEST
MINNESOTA THIS AFTERNOON. SHOWERS SHOULD END AT KFSD BY 21Z...BUT
WILL LIKELY PERSIST IN THE KSUX AREA UNTIL AROUND 23Z TO 00Z. GUSTY
SOUTHEAST WINDS WILL ENCOMPASS THE REGION AND AFFECT ALL TAF SITES
THIS AFTERNOON...ESPECIALLY AFTER RAIN SHOWERS END. WINDS WILL
CONTINUE TO GUST THROUGH THE NIGHT...AND A SECOND AREA OF RAIN AND
A FEW THUNDERSTORMS WILL SPREAD ACROSS THE REGION MAINLY AFTER 06Z.
RAIN SHOULD CONTINUE INTO LATE MORNING...GRADUALLY ENDING FOR ALL
TAF SITES BETWEEN 12Z AND 15Z. CEILINGS WILL LOWER AS RAIN ENDS
FRIDAY MORNING...BUT SHOULD STAY PREDOMINANTLY MVFR. /LAFLIN
&&
.PREV DISCUSSION.../ISSUED AT 455 AM CDT/
ABOUT AS COMPLEX A FORECAST AS CAN GET THIS MORNING...WITH
EVERYTHING FROM FIRE WEATHER...TO RAIN TIMING OVER A 5 DAY PERIOD...
SEVERE WEATHER...AND EVEN SNOW TO CONSIDER. SPRING IN ITS FINEST
FORM.
RIDGE ACROSS PLAINS STARTS TO BREAK DOWN TODAY AS ENERGY RIDES UP
THE ROCKIES SIDE. LEADING WAVE IS SHEARING NORTHWARD FROM SOUTHERN
WYOMING TO EASTERN COLORADO...AND RECENTLY HAS AIDED IN DEVELOPMENT
OF SHOWERS AND THUNDERSTORMS ACROSS WESTERN AND SOUTHWESTERN
NEBRASKA. MOISTURE RETURN IS TAKING THE LONG WAY AROUND...THROUGH
THE WESTERN PLAINS WITH THIS SYSTEM...WITH DEEP DRY LAYER TO
DISPLACE IN THE EAST AS THE LOW LEVEL JET SHIFTS GRADUALLY EASTWARD
THROUGH THE DAY. NOT OVERLY IMPRESSED WITH THE LEADING SYSTEM
TODAY...AND STILL FEEL AS IF POPS MAY APPEAR TO BE OVERDONE.
EVOLUTION EXPECTED TO FIND A BAND OF SCATTERED TO BROKEN LIGHT
SHOWERS PUSHING EAST/NORTHEAST ACROSS THE CWA. NOTHING OUT THERE
YET...BUT INCREASE IN 850-700 THETA E ADVECTION SHOULD HELP TO
GENERATE SOME SHRA BY DAYBREAK IN THE WESTERN THIRD. EASTWARD
MOVEMENT WILL BE SOMEWHAT DIFFICULT WITH DRIER AIRMASS AT LOWER
LEVELS...BUT WITH SOME INSTABILITY ROOTED AT 800-750 HPA...SHOWERY
PRECIP SHOULD INCREASINGLY THREATEN TO REACH THE GROUND...AND WHILE
FAIRLY UNLIKELY...COULD SEE A REMOTE RUMBLE OR TWO WITHIN THE BAND.
COVERAGE MAY MAX OUT AROUND MIDDAY OR EARLY AFTERNOON...WITH ENTIRE
ZONE WEAKENING THROUGH LATER AFTERNOON PUSHING EASTWARD INTO
SOUTHWEST MINNESOTA.
MUCH MORE IMPRESSED BY THE SYSTEM ROUNDING THE BASE OF THE TROUGH IN
NW ARIZONA...WHICH WILL LIFT THROUGH THE WESTERN PLAINS TONIGHT.
STRONGER MID LEVEL WAVE LIFTING NORTHEAST ALONG WITH DEEP LOWER
LEVEL MOISTURE TRANSPORT SHOULD FOCUS A MORE IMPRESSIVE COVERAGE OF
SHOWERS LIFTING NORTHEAST ACROSS THE CWA DURING THE OVERNIGHT.
INSTABILITY ON THE NOSE OF MID LEVEL DRYING WILL LIKELY HAVE SOME
BETTER THUNDER COVERAGE AS WELL. PRECIPITATION WILL CONTINUE NORTH
AND EAST EARLY IN THE DAY...AND THEN MAY FIND A LARGELY QUIET PERIOD.
LOW LEVEL JET VEERING EAST...AND WITH JET DRIVING FLOW MORE
SOUTHWEST...SHOULD ERODE THE LINGERING LOW LEVEL MOISTURE FROM WEST
TO EAST. IN FACT...WILL YIELD A FAIRLY MIXY DAY FOR THE AREA WHICH
CLEARS...WITH TEMPERATURES INTO THE UPPER 60S TO LOWER 70S...WHILE
CLOUDS SHROUDING THE FAR EAST COULD KEEP READINGS CLOSER TO 60. FIRE
DANGER FOR THE MOMENT CAME OUT HIGH...BUT IF DEWPOINTS CAN COLLAPSE
AND WINDS UP A BIT MORE...WOULD NOT BE SURPRISED TO FIND VERY HIGH
FIRE DANGER ALONG AND SOUTH OF INTERSTATE 90 IN SOUTHEAST SOUTH
DAKOTA...IN WARMER WEDGE BETWEEN APPROACHING FRONT AND THE MOIST
AXIS TO THE EAST.
NOT MUCH OF ANY APPRECIABLE CONVERGENCE ALONG THE COLD FRONT
APPROACHING FROM THE NORTHWEST...BUT KEPT JUST A VERY LOW END POP
AGAIN BY LATER AFTERNOON IN THE NORTH. ELSEWHERE...ANOTHER
DISTURBANCE RIDING QUICKLY IN FROM THE SOUTHWEST MAY IMPACT SOME
DEVELOPMENT NEAR THE RETREATING WARM FRONT ACROSS NORTHWEST IOWA
DURING THE LATER AFTERNOON...AND MAY HAVE TO WATCH FOR AN ISOLATED
MARGINALLY SEVERE STORM GIVEN THE LONG HODOGRAPH AND UP TO 750 J/KG
WEAKLY CAPPED INSTABILITY.
SURFACE FRONT WILL CONTINUE TO SLOWLY DROP SOUTHWARD THROUGH
SATURDAY...THEN WILL LIKELY STALL IN EASTERN NEBRASKA AS
LOW LEVEL FLOW BACKS AND GET COMBINATION OF ENHANCE WARM AIR
ADVECTION/MID LEVEL DEFORMATION FOCUSING PRECIPITATION FROM LATER
SATURDAY THROUGH SUNDAY NEAR AND NORTH OF THIS BOUNDARY. ONE WAVE
WILL FOCUS A GREATER CHANCE OF SHOWERS/THUNDER ACROSS NORTHWEST IOWA
SATURDAY EVENING BEFORE PEELING EASTWARD. THIS MAY PRESENT A RISK
FOR ISOLATED SEVERE STORMS NEAR THE HIGHWAY 20 CORRIDOR NORTHWARD
TOWARD SPENCER IOWA...WITH DEEP INSTABILITY SOUTH OF THE BOUNDARY
FROM 1500-2000 J/KG...AS WELL AS VERY LONG HODOGRAPHS...AND SHEAR
NICELY FOCUSED DOWN LOW NEAR THE LOCATION OF THE SURFACE BOUNDARY.
BIG CHANGE OVER THE LAST 24 HOURS HAS BEEN EVOLVING CONSENSUS OF
CLOSED OFF SYSTEM LIFTING NORTHEAST INTO THE REGION ON SUNDAY NIGHT
AND MONDAY. QUITE A CONSENSUS DEVELOPING QUICKLY...AND NOW LOOKS TO
BE AT BEST A MIXED PRECIPITATION SYSTEM...AND VERY LIKELY SOME AREAS
WITH ALL SNOWFALL. AT FACE VALUE...WITH 850 HPA TEMPS ON ORDER OF -4
TO -8C ON NORTHWEST FLANK OF SYSTEM BY LATE SUNDAY NIGHT...AND A
CONTINUED THREAT FOR SOME ELEVATED THUNDER INTO NORTHWEST IOWA INTO
SUNDAY NIGHT. STILL SOME WIGGLE ROOM ON THE TRACK OF MID LEVEL
WAVE...BUT FOR THE MOMENT HAVE DESIGNED FORECAST ON A MORE MODEST
WESTERN TRACK WHICH WOULD PLACE GREATER THREAT FOR PRECIPITATION/
SNOWFALL ACROSS THE WESTERN CWA LATER SUNDAY NIGHT INTO MONDAY ALONG
THE LOWER TO MID LEVEL FRONTOGENETIC ZONE...WITH DRY SLOT PUNCHING
IN NEAR KFSD AND EASTWARD...THEN PRECIP WRAPPING EASTWARD DURING THE
DAY MONDAY. A LOT OF DETAILS WILL SHAKE OUT THE NEXT DAY OR TWO...
BUT WOULD NOT BE SURPRISED TO END UP WITH A HIGHLIGHT WORTHY EVENT
GIVEN THE CURRENT CONSENSUS. MOST GUIDANCE WOULD FIND IT DIFFICULT
TO GET MUCH PAST THE LOWER 40S ON FULL MIXING ON MONDAY WITH
EXCEPTION OF THE FAR WEST AND SOUTHEAST...AND USED A BLEND OF RAW
GUIDANCE TO ACCOUNT FOR THIS WITH FORECAST FROM MONDAY INTO MONDAY
NIGHT.
TUESDAY QUIET WITH WEAK RIDGING BUILDING INTO THE AREA. KEPT IN THE
VERY SMALL POPS ON WEDNESDAY TO REFLECT WAVE IN NORTHWEST FLOW. NOT
MUCH POTENTIAL FOR MOISTURE RETURN...BUT VERY COOL IN THE MID LEVELS
AND WILL BE LIKELY BE UNSTABLE ENOUGH FOR SOME MID LEVEL SHOWERS.
/CHAPMAN
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
MN...NONE.
NE...NONE.
SD...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1135 AM MDT THU APR 12 2012
.AVIATION...18Z TAF ISSUANCE...
PESKY FOG AT KSNY AND LOW STRATUS AT KAIA AND KBFF WILL SLOWLY
ERODE EARLY THIS AFTERNOON AS THE NEXT UPPER-LEVEL DISTURBANCES
MOVES INTO THE AREA. SO EXPECT...IFR/LIFR CONDITIONS TO RETURN TO
VFR AT THESE SITES BY AROUND 20Z. TSTORMS EXPECTED AT KSNY 22Z-03Z
AS THE SYSTEM MOVES THRU. OTHERWISE...EXPECT VFR CONDITIONS TO
PREVAIL THROUGH THE REST OF THE PERIOD. THE ONE EXCEPTION WILL BE
AT KRWL WHERE SOME LOWER MVFR CIGS ARE EXPECTED LATER
TONIGHT/EARLY FRIDAY. HAHN
&&
.PREV DISCUSSION... /ISSUED 430 AM MDT THU APR 12 2012/
SHORT TERM...TODAY THROUGH FRIDAY...
THE RUC 500MB ANALYSIS SHOWS A STRONG SHORTWAVE MOVING NORTHWARD
ACROSS NORTHERN CO AND SOUTHERN WY AT THIS HOUR. THE FORCING FROM
THIS SHORTWAVE IS RESPONSIBLE FOR THE LIGHT RAIN ACTIVITY CURRENTLY
MOVING NORTHWARD OVER THE NE PANHANDLE. THE GFS SHOWS A NARROW
TONGUE OF SMALL SFC INSTABILITY OVER THE PANHANDLE...WITH LI VALUES
BETWEEN 0 AND -2C...HOWEVER THE DECREASING TREND OF REFLECTIVITY
OVER THE LAST HOUR SUGGESTS THAT ANY TSTM ACTIVITY WILL BE REALLY
LIMITED. SFC ANALYSES SHOW THE SFC TROUGH AND COLD FRONT JUST TO
THE WEST OF CHEYENNE...WITH DRIER AIR AND SW WINDS TO THE WEST AND
MOIST SOUTHERLY WINDS TO THE EAST OF THIS FEATURE. THE FRONT WILL
PROGRESS EASTWARD OVER THE CWA THIS MORNING...REACHING THE NE
PANHANDLE BY LATE MORNING AND SCOURING OUT ANY REMAINING LOW
CLOUDINESS AND SHOWER ACTIVITY. LLVL GRADIENTS INCREASE BEHIND THE
FRONT WITH 700MB WINDS AROUND 40-50 KTS BETWEEN 12 AND 18Z OVER
MAINLY CONVERSE AND NIOBRARA COUNTIES. THIS WILL LIKELY CAUSE WIND
GUSTS AT ARLINGTON TO APPROACH HIGH WIND CRITERIA FOR A SHORT
TIME...BUT CONFIDENCE IS NOT HIGH ENOUGH TO ISSUE A WARNING AT THIS
TIME. OTHERWISE...EXPECT RELATIVELY DRY CONDITIONS OVER THE CWA
THROUGH LATE MORNING IN THE SUBSIDENCE BEHIND THE SHORTWAVE AND
FROPA. ANOTHER WEAKER SHORTWAVE MOVES OVER THE CWA DURING THE AFTN
AND EVENING. DUE TO THE LIFT FROM THIS FEATURE ALONG WITH 500MB
TEMPS DROPPING TO -20C BY AFTN AND LI VALUES 0 TO -1C...INCLUDED A
SLIGHT CHANCE OF TSTMS OVER MOST AREAS.
RELATIVELY QUIET WEATHER DAY ON FRI WITH WEAK SOUTHWESTERLY MIDLEVEL
FLOW AND NO DISCERNIBLE PERTURBATIONS IN THE FLOW. TEMPS WILL BE
COOL WITH 700MB TEMPS AROUND -2C. WITH WEAK LLVL GRADIENTS OVER THE
AREA WINDS WILL BE WEAK WESTERLY. THERE IS ENOUGH MIDLEVEL (700-500
MB) MOISTURE IN THE FLOW TO INCLUDE A CHANCE TO SLIGHT CHANCE OF
RAIN SHOWERS OVER AREAS TO THE WEST OF THE LARAMIE RANGE. ATTENTION
THEN TURNS TO THE POTENTIAL MAJOR WINTER STORM DURING THE WEEKEND.
LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
MUCH COOLER AND WET WEATHER WILL AFFECT THE REGION SATURDAY THROUGH
SUNDAY NIGHT. THIS EVENT COULD HAVE MAJOR IMPACTS ON TRAVEL...OUTDOOR
ACTIVITIES AND LIVESTOCK DURING THAT TIME WITH SIGNIFICANT ACCUMULATING
SNOW POSSIBLE.
CLOUDS WILL INCREASE OVER THE CWA FRIDAY NIGHT WITH SHOWERS BECOMING
MORE WIDESPREAD THROUGH SATURDAY AFTERNOON. ISOLATED THUNDERSTORMS
WILL ALSO BE POSSIBLE SATURDAY AFTERNOON AND EARLY EVENING. ALL OF
THE PRECIPITATION IS AHEAD OF THE APPROACHING MID AND UPPER LEVEL LOW
WHICH WILL BE NEAR THE FOUR CORNERS AREA BY 00Z SUNDAY. THE
ASSOCIATED SURFACE LOW WILL BE DEVELOPING OVER EASTERN COLORADO
SATURDAY AFTERNOON. THE 00Z MODELS...OTHER THAN THE NAM...HAVE
BECOME MORE CONSISTENT WITH MOVEMENT OF THE SYNOPTIC FEATURES AND THE
QPF. BY 12Z SUNDAY...THE STORM SYSTEM WILL BE OVER EASTERN COLORADO
AND THEN WILL MOVE SLOWLY NORTHEAST THROUGH 00Z MONDAY BEFORE
ACCELERATING SUNDAY NIGHT AND MONDAY. THE PRECIPITATION WILL CHANGE
FROM RAIN TO SNOW SATURDAY NIGHT AND EARLY SUNDAY MORNING AS THE
SURFACE AND 700 MB TEMPERATURES COOL AND THE 1000 TO 500 MB THICKNESS
VALUES LOWER. THE ACCUMULATING SNOW WILL BE FOCUSED ON THE WEST PART
OF THE CWA EARLY SATURDAY NIGHT AND THEN SHIFT EAST TO THE SOUTHEAST
HALF OF THE CWA LATER SATURDAY NIGHT AND FOR MUCH OF SUNDAY. ALONG
WITH THE SURFACE FORCING WILL BE DIFFLUENCE ALOFT AND MID LEVEL
CONVERGENCE. SNOWFALL AMOUNTS WILL BE UP TO A FOOT OVER AND NEAR
THE SNOWY AND SIERRA MADRE RANGES SATURDAY NIGHT AND THEN BETWEEN 6
AND 14 INCHES OVER THE SOUTHEAST HALF OF THE CWA LATE SATURDAY NIGHT
THROUGH SUNDAY. ALONG WITH THE SNOW WILL BE STRONG NORTHEAST WINDS
GUSTING AS HIGH AS 50 MPH. BLIZZARD CONDITIONS COULD RESULT AT TIMES
OVER THAT AREA LATE SATURDAY NIGHT AND SUNDAY. A LESS AMPLIFIED
WIND FLOW ALOFT WILL BE OVER THE ROCKIES INTO MID WEEK. SEVERAL
SHORTWAVE TROUGHS AND A RELATIVELY UNSTABLE ATMOSPHERE WILL PRODUCE
SHOWERS MONDAY AND TUESDAY AND AGAIN NEXT THURSDAY. TEMPERATURES
WILL SLOWLY MODERATE THROUGH THAT TIME. FOR THE LATER PARTS OF THIS
FORECAST FOLLOWED MORE CLOSELY THE 00Z ECMWF.
&&
.FIRE WEATHER...
DRY AND BREEZY CONDITIONS WILL OCCUR THIS AFTERNOON OVER SOUTHEAST
WYOMING AND THE NEBRASKA PANHANDLE AFTER A COLD FRONT MOVES OVER THE
AREA THIS MORNING...WHICH WILL RESULT IN AN ELEVATED FIRE DANGER
THREAT TO THE EAST OF THE LARAMIE RANGE. DUE TO THE DRIER
AIR...MINIMUM RELATIVE HUMIDITIES WILL BE IN THE 15 TO 20 PERCENT
RANGE TO THE EAST OF THE LARAMIE RANGE. IN ADDITION...WESTERLY
WINDS WILL BE SUSTAINED AT 20 TO 25 MPH WITH OCCASIONAL GUSTS TO 35
MPH. A STORM SYSTEM MOVING INTO THE AREA ON SAT AFTN THROUGH SUN
EVENING HAS THE POTENTIAL TO BRING WIDESPREAD RAIN AND SNOW...ENDING
ALL FIRE WEATHER CONCERNS THROUGH EARLY NEXT WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM/FIRE WEATHER...FINCH
LONG TERM...WEILAND