Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/14/15
AREA FORECAST DISCUSSION
NWS TUCSON AZ
330 PM MST TUE MAY 12 2015
.SYNOPSIS...THERE IS A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS
MAINLY EAST OF TUCSON TONIGHT. DRY CONDITIONS WILL THEN PREVAIL
WEDNESDAY INTO THURSDAY. A STRONG LOW PRESSURE SYSTEM WILL BRING A
CHANCE OF SHOWERS AND THUNDERSTORMS FRIDAY INTO SATURDAY. COOLER
TEMPERATURES AND GUSTY WINDS WILL ACCOMPANY THIS SYSTEM. EXPECT DRY
CONDITIONS AND MUCH WARMER TEMPERATURES EARLY NEXT WEEK.
&&
.DISCUSSION...IR/VISIBLE SATELLITE IMAGERY DEPICTED FAIRLY THICK MID
AND HIGH-LEVEL CLOUDS ACROSS MUCH OF SE ARIZONA THIS AFTERNOON. MORE
EXTENSIVE BREAKS IN THE OVERCAST WERE NOTED ACROSS WRN PIMA COUNTY.
THE BACK EDGE OF THIS CLOUD MASS REPRESENTING A SHORTWAVE TROUGH
AXIS EXTENDED FROM SRN CALIFORNIA SOUTHWARD TO NEAR THE BAJA
CALIFORNIA SPUR. MEANWHILE...A VERY DRY SURFACE ENVIRONMENT WAS
ONGOING WITH DEWPOINTS AT LOWER ELEVATIONS VALID 22Z RANGING FROM
THE MID TEENS TO MID 20S. HAVE FAVORED SEVERAL RUC HRRR SOLUTIONS
FOR PRECIP POTENTIAL THRU TONIGHT.
THUS...THERE IS A SLIGHT CHANCE OF SHOWERS/TSTMS THIS EVENING FROM
TUCSON EWD/SWD TO THE NEW MEXICO/INTERNATIONAL BORDERS. A SLIGHT
CHANCE OF SHOWERS CONTINUES MAINLY NEAR THE NEW MEXICO BORDER LATE
TONIGHT. GIVEN THE VERY DRY NEAR-SURFACE ENVIRONMENT...ANY
MEASURABLE PRECIP AMOUNTS WILL BE QUITE LIGHT. CLEARING SKIES WILL
OCCUR FROM WEST-TO-EAST LATE TONIGHT AS THE MID-LEVEL TROUGH AXIS
MOVES INTO SWRN NEW MEXICO.
FLOW ALOFT WILL BECOME INCREASINGLY SWLY WED-THUR IN RESPONSE TO
DEEPENING LOW PRESSURE ALOFT OVER THE ERN PACIFIC. THE TIGHTENING
MID-LEVEL GRADIENT WILL PRODUCE BREEZY TO WINDY CONDITIONS...
ESPECIALLY DURING THE AFTERNOON HOURS. EXPECT THE STRONGEST WIND
SPEEDS TO OCCUR THUR.
12/12Z GFS/ECMWF/CMC WERE IN GOOD AGREEMENT WITH DEPICTING A 550 DM
LOW TO BE CENTERED NEAR THE CENTRAL CALIFORNIA COAST FRI MORNING.
THIS UPPER LOW IS THEN PROGGED TO BE CENTERED OVER WYOMING SAT
MORNING...WITH A MID-LEVEL TROUGH AXIS TO EXTEND SWWD INTO SRN
ARIZONA. BASED ON THESE SOLUTIONS...APPEARS THE BEST CHANCE OF
MEASURABLE PRECIP FOR THE TUCSON METRO AREA WOULD OCCUR FRI NIGHT.
THE GRIDDED DATA POP FIELDS WERE ADJUSTED TO REFLECT THIS SCENARIO.
AT ANY RATE...THERE IS A SLIGHT CHANCE OF SHOWERS MAINLY NORTH OF
TUCSON FRI MORNING. PRECIP CHANCES INCREASE FRI AFTERNOON...AND A
CHANCE OF SHOWERS/TSTMS EXISTS ACROSS MUCH OF THE AREA FRI NIGHT. A
CHANCE OF SHOWERS CONTINUES SAT MAINLY ACROSS THE WHITE MOUNTAINS.
DRY CONDITIONS SHOULD OCCUR BY SAT AFTERNOON FROM TUCSON WWD ACROSS
THE WRN DESERTS. DRY CONDITIONS WILL PREVAIL AREA-WIDE LATE SAT
NIGHT AND CONTINUE THRU TUE UNDER GENERALLY SWLY FLOW ALOFT.
WARMER TEMPS WILL OCCUR WED FOLLOWED BY A FEW DEGS OF COOLING
THUR...THEN MORE SIGNIFICANT COOLING IS ON TAP FRI. MARKEDLY WARMER
TEMPS WILL PREVAIL SUN-TUE.
&&
.AVIATION...VALID THRU 14/00Z.
EXPECT ISOLATED -SHRA/-TSRA FROM KTUS VICINITY EASTWARD TO THE NEW
MEXICO BORDER THIS EVENING. ISOLATED -SHRA WILL THEN PREVAIL MAINLY
NEAR THE NEW MEXICO BORDER LATE TONIGHT...THEN DRY CONDITIONS WILL
OCCUR AREA-WIDE WEDNESDAY. OTHERWISE...CLOUD DECKS THRU ABOUT 06Z-
09Z WEDNESDAY WILL GENERALLY BE AT 6-12K FT AGL FOLLOWED BY
DECREASING CLOUDS EARLY WEDNESDAY MORNING. CLEAR SKIES TO SCATTERED
CLOUDS ABOVE 10K FT AGL WILL PREVAIL WEDNESDAY AFTERNOON. SURFACE
WIND EARLY THIS EVENING AND WEDNESDAY AFTERNOON WILL BE SLY/SWLY AT
12-20 KTS WITH GUSTS OF 20-30 KTS. SURFACE WIND WILL GENERALLY BE
LESS THAN 10 KTS AT OTHER TIMES. AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.
&&
.FIRE WEATHER...THERE IS A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS MAINLY EAST OF TUCSON TONIGHT. DRY CONDITIONS WILL
THEN PREVAIL WEDNESDAY INTO THURSDAY. THE COMBINATION OF STRONG AND
GUSTY WINDS AND LOW RELATIVE HUMIDITIES MAY CREATE CRITICAL FIRE
WEATHER CONDITIONS AT LOWER ELEVATIONS THURSDAY AFTERNOON AND EARLY
THURSDAY EVENING. HOWEVER...WIND SPEEDS AND RELATIVE HUMIDITIES
NEEDED TO ACHIEVE RED FLAG CRITERIA WILL BE MARGINAL AND SHORT-
LIVED. A STRONG STORM SYSTEM MOVING NORTH OF THE AREA WILL THEN
BRING A CHANCE OF SHOWERS AND THUNDERSTORMS FRIDAY INTO SATURDAY.
COOLER TEMPERATURES AND GUSTY WINDS WILL OCCUR WITH THIS SYSTEM.
EXPECT DRY CONDITIONS WITH MUCH WARMER TEMPERATURES EARLY NEXT WEEK.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
FRANCIS
AREA FORECAST DISCUSSION
NWS TUCSON AZ
910 AM MST TUE MAY 12 2015
.SYNOPSIS...THERE IS A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS
EAST OF TUCSON THROUGH WEDNESDAY MORNING. OTHERWISE...DRY CONDITIONS
WILL PREVAIL INTO THURSDAY. A STRONG LOW PRESSURE SYSTEM FROM THE
EASTERN PACIFIC WILL THEN BRING A CHANCE OF SHOWERS AND
THUNDERSTORMS THURSDAY NIGHT INTO SATURDAY. COOLER TEMPERATURES AND
GUSTY WINDS WILL ALSO OCCUR.
&&
.DISCUSSION...IR/VISIBLE SATELLITE IMAGERY AND SURFACE OBSERVATIONS
INDICATE PARTLY CLOUDY SKIES ACROSS THE WHITE MOUNTAINS...AND MOSTLY
CLOUDY TO CLOUDY SKIES ELSEWHERE. THE THICKER CLOUDINESS AS PER
ENHANCED COLDER CLOUD TOPS EXTENDED FROM TUCSON SOUTHWARD TO THE
INTERNATIONAL BORDER. DEWPOINTS AT LOWER ELEVATIONS VALID 16Z RANGED
FROM THE MID 20S-MID 40S. THESE TEMPS WERE NEARLY 2-5 DEGS F HIGHER
VERSUS 24 HOURS AGO EXCEPT IN THE VICINITY OF SAFFORD...WHERE THE
DEWPOINT WAS 15 DEGS HIGHER VERSUS THIS TIME MON.
SURFACE TEMPS VALID 16Z WERE GENERALLY 2-9 DEGS F COOLER VERSUS 24
HOURS AGO. 12/12Z KTWC SOUNDING TOTAL PRECIP WATER VALUE WAS 0.40
INCH. THE PROFILE EXHIBITED A VERY DRY SURFACE-500 MB LAYER AND SOME
SATURATION OF THE COLUMN ABOVE 500 MB. 12/12Z UPPER AIR PLOTS
DEPICTED RIDGE AXIS FROM TEXAS NWWD INTO MONTANA...AND A 548 DM LOW
WAS CENTERED OVER SWRN OREGON. MODERATE TO STRONG GENERALLY SWLY
FLOW PREVAILED OVER SE ARIZONA.
BASED ON SATELLITE IMAGERY AND THE 12/12Z NAM...GRIDDED DATA SKY
VALUES WERE INCREASED TO REPRESENT INCREASED CLOUDINESS VERSUS THE
PREVIOUS FORECAST. THE 12/12Z NAM LIMITED MEASURABLE PRECIP TO THE
WHITE MOUNTAINS TONIGHT. HOWEVER...THE 12/14Z RUC HRRR WAS FURTHER
WEST WITH THE POTENTIAL FOR MEASURABLE PRECIP VERSUS THE NAM...AND
YIELDED SCATTERED COVERAGE ACROSS GREENLEE/GRAHAM/COCHISE COUNTIES
THIS EVENING. THE INHERITED OFFICIAL FORECAST APPEARS TO BE A GOOD
COMPROMISE BETWEEN THESE SOLUTIONS.
THUS...THERE IS A SLIGHT CHANCE OF SHOWERS/TSTMS THIS AFTERNOON
ACROSS THE WHITE MOUNTAINS WITH DRY CONDITIONS ELSEWHERE. A SLIGHT
CHANCE OF SHOWERS/TSTMS EXISTS TONIGHT ACROSS ERN SECTIONS WITH DRY
CONDITIONS CONTINUING ELSEWHERE. A FEW LINGERING SHOWERS MAY OCCUR
WED MORNING NEAR THE NEW MEXICO BORDER...THEN DRY CONDITIONS WILL
PREVAIL AREA WIDE INTO THUR AFTERNOON. HIGH TEMPS THIS AFTERNOON
WILL GENERALLY BE A FEW DEGS COOLER VERSUS MON.
&&
.AVIATION...VALID THRU 13/18Z.
EXPECT ISOLATED -SHRA/-TSRA EAST OF KTUS TO THE NEW MEXICO BORDER
INTO WEDNESDAY MORNING. OTHERWISE...INCREASING MAINLY MID AND HIGH-
LEVEL MOISTURE THIS MORNING WILL PRODUCE BROKEN TO OVERCAST CLOUD
DECKS MAINLY AT 10-15K FT AGL THIS AFTERNOON INTO WEDNESDAY MORNING.
SURFACE WIND THIS AFTERNOON AND EARLY THIS EVENING WILL BE SLY/SWLY
AT 12-20 KTS WITH GUSTS OF 20-30 KTS. SURFACE WIND WILL THEN
DIMINISH TO GENERALLY LESS THAN 10 KTS 02Z-04Z WEDNESDAY AND
CONTINUE INTO WEDNESDAY MORNING. AVIATION DISCUSSION NOT UPDATED FOR
TAF AMENDMENTS.
&&
.FIRE WEATHER...THERE IS A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS EAST OF TUCSON INTO EARLY WEDNESDAY. OTHERWISE...DRY
CONDITIONS WILL PREVAIL THROUGH THURSDAY. EXPECT OCCASIONALLY GUSTY
WINDS DURING THE AFTERNOON HOURS INTO WEDNESDAY. A STRONG PACIFIC
LOW PRESSURE SYSTEM WILL APPROACH CALIFORNIA THURSDAY. THIS SYSTEM
WILL PRODUCE STRONG SOUTHWEST WINDS WITH THE POTENTIAL FOR
BORDERLINE RED FLAG CONDITIONS IN ONLY A FEW PLACES. AS THE STORM
MOVES CLOSER ON FRIDAY...WINDS WILL INCREASE FURTHER. HOWEVER...
HUMIDITY LEVELS WILL BE HIGHER WITH LOWER TEMPERATURES AND A CHANCE
FOR SHOWERS AND/OR THUNDERSTORMS. THE SOUTHERN PORTION OF THIS
SYSTEM WILL MOVE ACROSS ARIZONA SATURDAY MAINTAINING A THREAT OF
SHOWERS AND THUNDERSTORMS. DAYTIME TEMPERATURES WILL BE 10-15
DEGREES COOLER THAN NORMAL SATURDAY...THEN DRIER AND SOMEWHAT WARMER
CONDITIONS WILL OCCUR SUNDAY AND MONDAY.
&&
.PREV DISCUSSION...EXPECT A BRIEF RESPITE FROM THE SHOWERS FROM LATE
WEDNESDAY THROUGH LATE THURSDAY BEFORE A MUCH STRONGER PACIFIC
SYSTEM WILL BEGIN TO AFFECT THE REGION LATE THURSDAY EVENING AND
ESPECIALLY OVERNIGHT INTO THE EARLY MORNING HOURS ON FRIDAY AS AN
UPPER LOW WILL BE CENTERED OVER THE GREAT BASIN AT THAT TIME.
ISOLATED TO SCATTERED SHOWERS WILL AFFECT MOSTLY THE HIGHER TERRAIN
THURSDAY NIGHT INTO EARLY FRIDAY. BY FRIDAY AFTERNOON EXPECT
ISOLATED SHOWERS AND THUNDERSTORMS AREA-WIDE WITH SCATTERED ACTIVITY
OVER PARTS OF GRAHAM AND GREENLEE COUNTIES. THIS WILL CONTINUE INTO
FRIDAY NIGHT AND EARLY SATURDAY. MODELS STILL AT ODDS WITH EACH
OTHER ON BOTH TIMING AND POP VALUES. LATEST MOS GUIDANCE HAS FLIP-
FLOPPED FROM THIS TIME YESTERDAY...WITH THE GFS POPS VALUES RANGING
FROM SINGLE DIGITS TO SLIGHT CHANCES ON FRIDAY...THEN IN THE SOLID
CHANCE CATEGORY FOR SATURDAY. MEANWHILE...THE ECMWF MOS NUMBERS FOR
POP REFLECT SLIGHT CHANCE TO LOW END CHANCE FOR FRIDAY AND SIMILAR
FOR SATURDAY. GIVEN THIS CONTINUED UNCERTAINTY...OPTED TO ONLY MAKE
MINOR ADJUSTMENTS TO THE FORECAST AND TO BLEND WITH SURROUNDING
OFFICES.
BY SATURDAY THE UPPER LOW WILL HAVE LIFTED TO THE NORTHEAST INTO THE
NORTHERN ROCKIES...MORE SPECIFICALLY OVER SOUTHEASTERN IDAHO AND
CENTRAL WYOMING. THE TAIL END OF THIS SYSTEM WILL EXTEND ACROSS NEW
MEXICO AND INTO SOUTHEAST ARIZONA AND NORTHERN SONORA. BY THAT TIME
THE BULK OF THE MOISTURE WITH THIS SYSTEM WILL BE TO OUR NORTH...SO
ONLY EXPECTING A SLIGHT CHANCE OF MOUNTAIN SHOWERS AND/OR
THUNDERSTORMS WITH A SLIGHTLY BETTER THREAT FOR PARTS OF GRAHAM AND
GREENLEE COUNTIES.
BY EARLY SUNDAY THE LOW WILL BE OVER THE NORTHERN ROCKIES/PLAINS
STATES WITH WEAK RIDGING BUILDING IN BEHIND THE SYSTEM AND A RETURN
TO DRY WEATHER THROUGH THE REMAINDER OF THE FORECAST PERIOD...ALONG
WITH WARMING TEMPERATURES INTO EARLY NEXT WEEK.
FOR TUCSON...HIGH TEMPERATURES WILL GENERALLY RANGE FROM 2 TO 4 DEGS
BELOW NORMAL TODAY THROUGH THURSDAY...THEN 12 TO 16 DEGS BELOW
NORMAL FOR FRIDAY AND SATURDAY. THEREAFTER...AROUND 8 TO 10 DEGS
BELOW NORMAL FOR SUNDAY AND 3 TO 5 DEGS BELOW NORMAL FOR MONDAY. LOW
TEMPS WILL BE NEAR NORMAL WEDNESDAY THROUGH FRIDAY MORNINGS...THEN 6
TO 8 DEGS BELOW NORMAL FOR THE WEEKEND AND 2 TO 4 DEGS BELOW NORMAL
FOR EARLY NEXT WEEK.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
DISCUSSION...FRANCIS
PREVIOUS DISCUSSION...MOLLERE
AVIATION/FIRE WEATHER...HUMPHREYS
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
256 PM MDT TUE MAY 12 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 256 PM MDT TUE MAY 12 2015
AIRMASS IS BECOMING UNSTABLE ALONG THE FRONT RANGE AND NEAR BY
EASTERN PLAINS WHERE CAPES ARE UP TO 1000 J/KG. SHOWERS AND STORMS
HAVE BEEN SLOW TO FORM OVER THE HIGHER TERRAIN WHERE DEW POINTS
ARE IN THE 20S. THE HRRR AND RAP CONTINUE TO SHOW ISOLATED TO
SCATTERED CONVECTION LATER THIS AFTERNOON. AS THESE STORMS MOVE
OFF THE HIGHER TERRAIN...THEY WILL ENCOUNTER GREATER MOISTURE AND
INSTABILITY. EXPECT THE STORMS TO BE CAPABLE OF PRODUCE BRIEF
HEAVY...GUSTY OUTFLOW WINDS TO 40 MPH AND SMALL HAIL. WILL KEEP
THE ISOLATED TO SCATTERED POPS IN THE FORECAST FOR THE EVENING
HOURS.
A SHORT WAVE TROUGH CURRENTLY OVER BAJA CALIFORNIA WILL LIFT
NORTHEAST ACROSS THE REGION ON WEDNESDAY. EXPECT MOSTLY CLOUDY
SKIES AHEAD OF THIS FOR WEDNESDAY. BEST LIFT AND MOISTURE WILL
REMAIN TO THE SOUTH AND EAST OF THE AREA. HOWEVER SHOULD BE ENOUGH
MOISTURE AND LIFT WITH FOR SCATTERED SHOWERS AND THUNDERSTORMS.
CAPES WILL BE LESS THAN 500 J/KG...SO EXPECT STORMS TO STAY BELOW
SEVERE THRESHOLDS. LOWERED HIGH TEMPERATURES A FEW DEGREES DUE TO
THE CLOUDINESS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 256 PM MDT TUE MAY 12 2015
WEAK QG ASCENT SHOULD STILL BE IMPACTING MUCH OF THE CWA AT 00Z
THURSDAY AND WILL GRADUALLY TRANSITION TO SUBSIDENCE OVERNIGHT AS
UPPER LEVEL RIDGING MOVES IN. THIS WILL ALLOW THURSDAY TO HAVE
LOWER POPS ALTHOUGH PROBABLY NOT COMPLETELY ZERO...ESPECIALLY IN
THE MOUNTAINS.
THE NEXT WAVE AND QG ASCENT BEGINS IN THE MORE SOUTHERLY FLOW ON
FRIDAY WHICH SHOULD ALLOW FOR A BIT MORE SHOWER COVERAGE IN THE
MOUNTAINS DURING THE NORMAL DIURNAL TIMES BUT STILL NOTHING
TREMENDOUS. SHOWER ACTIVITY ON THE PLAINS WILL BE BATTLING A LACK
OF UPSLOPE SO PRECIPITATION THERE WILL BE SPOTTY AT BEST.
THE SYSTEM FOR SATURDAY IS LOOKING A BIT LESS PROMISING THAN
EARLIER. SOME SPREAD IN THE SOLUTIONS OF THE UPPER LOW POSITION BUT
THE MODELS ARE SHOWING SOME QG ASCENT OVER THE CWA ALONG WITH LIGHT
QPF. AGAIN...NOTHING TERRIBLY NOTEWORTHY.
STRONG QG SUBSIDENCE IS FORECAST ON SUNDAY ALONG WITH A PUSH OF LOW
LEVEL HIGH PRESSURE FROM THE NORTH WHICH MAY PUT A SIGNIFICANT
DAMPER ON THE PRECIPITATION THREAT SUNDAY. THE UPPER RIDGE MOVES
EAST OF COLORADO ON MONDAY FOR A SLIGHT INCREASE IN CONVECTIVE
ACTIVITY BY TUESDAY.
ALL IN ALL AT THIS TIME IT APPEARS THAT THERE IS A RATHER LOW RISK
OF HEAVY PRECIPITATION THAT COULD WORSEN THE FLOODING SITUATION.
MOREOVER...TEMPERATURES WILL REMAIN ON THE COOL SIDE WHICH WILL
LESSEN THE MELTING OF THE SNOWPACK.
&&
.AVIATION...(FOR THE TAFS THROUGH 00Z WEDNESDAY LATE AFTERNOON)
ISSUED AT 256 PM MDT TUE MAY 12 2015
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH WEDNESDAY. ISOLATED
TO SCATTERED THUNDERSTORMS ARE EXPECTED 22-03Z TODAY. ANOTHER
ROUND OF AFTERNOON THUNDERSTORMS ARE EXPECTED FOR
WEDNESDAY...LIKELY A LITTLE EARLIER. THE STORMS WILL BE CAPABLE OF
PRODUCING WIND GUSTS TO 35 KNOTS...BRIEF HEAVY RAIN AND SMALL
HAIL. OUTSIDE OF OUTFLOW WINDS FROM THUNDERSTORMS...WINDS WILL BE
SOUTHERLY AT KAPA AND KDEN. THROUGH WEDNESDAY. A WEAK DENVER
CYCLONE MAY CAUSE WINDS TO TURN NORTHWESTERLY AFTER 12Z WEDNESDAY
AT KDEN.
&&
.HYDROLOGY...
ISSUED AT 256 PM MDT TUE MAY 12 2015
THE SOUTH PLATTE RIVER IS CRESTING OVER WESTERN MORGAN COUNTY. THE
CREST IS EXPECTED TO MOVE DOWN STREAM THROUGH MORGAN COUNTY THE NEXT
24 HOURS. FORECAST CRESTS HAVE BEEN SLIGHTLY LOWERED THIS MORNING
ALONG THE SOUTH PLATTE RIVER.
ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED THIS EVENING AND
WEDNESDAY AFTERNOON AND EVENING. BRIEF HEAVY RAIN IS POSSIBLE WITH
THE THUNDERSTORMS. BEST CHANCE FOR HEAVY RAIN WILL BE WEDNESDAY
AFTERNOON WHERE UP TO AN INCH WILL BE POSSIBLE UNDER THE STRONGEST
STORMS.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...MEIER
LONG TERM...ET
AVIATION...MEIER
HYDROLOGY...MEIER
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1040 AM MDT TUE MAY 12 2015
.UPDATE...
ISSUED AT 1040 AM MDT TUE MAY 12 2015
THE LATEST HRRR ...ARW...NMM AND NAM SHOW THE BEST CHANCE FOR
SHOWERS AND STORMS ALONG THE FRONT RANGE FROM DENVER TO GREELEY TO
FORT MORGAN. WILL INCREASE POPS INTO THE SCATTERED RANGE FOR THIS.
WITH THE DRY LOW LEVELS...THE CONVECTION WILL PRODUCE GUSTY
OUTFLOW WINDS. ANY HEAVY RAIN WILL BE LOCALIZED AND LIKELY LESS
THAN A HALF INCH. NO OTHER CHANGES TO THE FORECAST ARE PLANNED.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 419 AM MDT TUE MAY 12 2015
UPPER RIDGE IS SHIFTING EAST OF COLORADO WITH SURFACE HIGH
PRESSURE ON THE PLAINS. HIGH LEVEL MOISTURE MOVING ACROSS IN
SOUTHWEST FLOW ALOFT...WHILE LOW LEVELS REMAIN DRY. LOOKING LIKE
THERE WILL BE SOME DECREASE IN THE HIGH LEVEL MOISTURE LATER
TODAY...BUT CONVECTION WILL LIKELY OFFSET THAT. STICKING WITH THE
FORECAST OF SCATTERED CONVECTION OVER THE MOUNTAINS...WITH
ISOLATED STORMS WORKING ONTO THE PLAINS LATE IN THE DAY. WITH
CAPES EXPECTED TO BE 500-1000 J/KG OVER THE MOUNTAINS AND DRY LOW
LEVELS...SOME OF THE STORMS WILL LIKELY PRODUCE GUSTY WINDS BUT
WITH LIMITED FLOW ALOFT NOT TOO MUCH OF A SEVERE THREAT. THE
PLAINS WILL BE WEAKLY CAPPED MOST OF THE DAY...MOST LIKELY
CONVECTION WILL BE ON OUTFLOWS FROM THE MOUNTAIN CONVECTION.
ANY SIGNIFICANT RAIN SHOULD BE ON A SMALL SCALE SO NOT MUCH IMPACT
TO CURRENT RIVER CONDITIONS.
I ONLY MADE MINOR ADJUSTMENTS TO THE FORECAST...INCREASING CLOUDS
THIS MORNING AND ADDING A BIT MORE WIND ON THE PLAINS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 419 AM MDT TUE MAY 12 2015
STARTING WEDNESDAY MORNING A SHORTWAVE TROUGH WILL MOVE NORTH OUT OF
THE DESERT SOUTHWEST ACROSS EASTERN COLORADO. MOISTURE AND
PRECIPITATION WILL MOVE INTO THE MOUNTAINS FIRST WITH A LEE SIDE
TROUGH DOMINATING THE NE COLORADO PLAINS. THROUGH THE DAY WEDNESDAY
WITH THE INCREASE OF INSTABILITY FROM HEATING AND MOISTURE AFTERNOON
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE. PERIODS OF HEAVIER RAIN
WILL BE POSSIBLE UNDER THE STRONGER STORMS...ESPECIALLY OVER THE
EASTERN PLAINS. SNOW IN THE MOUNTAINS ABOVE 10000FT WILL BE POSSIBLE
WITH LIGHT ACCUMULATIONS ON WEDNESDAY. TEMPERATURES ON WEDNESDAY
WILL BE SLIGHTLY COOLER WITH HIGHS IN THE UPPER 60S.
THE TROUGH WILL CONTINUE TO MOVE NORTH ON THURSDAY WITH SURFACE HIGH
PRESSURE PUSHING INTO WESTERN COLORADO AND A LEE TROUGH FORMING OVER
EASTERN COLORADO. UPPER LEVEL RIDGING THURSDAY WILL HELP DRY OUT
CONDITIONS BRINGING ANOTHER SHORT REPRIEVE FROM RAIN. TEMPERATURES
THURSDAY WILL BOUNCE BACK TO SEASONAL NORMALS WITH HIGHS REACHING
INTO THE MID 70S.
MODELS ARE CURRENTLY IN DECENT AGREEMENT REGARDING THE NEXT SYSTEM
FORMING OFF THE COAST OF CALIFORNIA BY THURSDAY EVENING. UPPER LEVEL
FLOW WILL BE STRONG FROM THE SOUTHWEST. SEVERAL EMBEDDED
DISTURBANCES WILL KEEP A STEADY STREAM OF MOISTURE MOVING INTO
COLORADO THAT WILL HELP BRING A SLIGHT CHANCE OF AFTERNOON SHOWERS
AND THUNDERSTORMS TO THE NE REGION. FOR FRIDAY...TEMPERATURES REACH
INTO THE UPPER 70S WITH INCREASED CAPE VALUES ALONG THE KS BORDER
ALONG WITH A SHARP DRY LINE THAT COULD AID IN STRONG THUNDERSTORM
DEVELOPMENT FOR FRIDAY AFTERNOON AND EVENING.
ON SATURDAY AND SUNDAY THE UPPER LEVEL LOW WILL CONTINUE TO MAKE ITS
EASTWARD PROGRESSION WITH STEADY MOISTURE OVER THE MOUNTAINS AND
PLAINS THROUGH THE WEEKEND. TEMPERATURES WILL DIP BACK TO JUST BELOW
NORMALS WITH HIGHS ONLY GETTING INTO THE MID TO UPPER 60S. THE
SYSTEM LIFTS OUT TO THE NORTHEAST BY MONDAY EVENING BRINGING UPPER
LEVEL RIDGING AND WARMER TEMPERATURES FOR TUESDAY.
&&
.AVIATION...(FOR THE TAFS THROUGH 18Z WEDNESDAY MORNING)
ISSUED AT 1040 AM MDT TUE MAY 12 2015
VFR THROUGH WEDNESDAY. ISOLATED TO SCATTERED THUNDERSTORMS ARE
EXPECTED BETWEEN 21Z AND 03Z WITH THE MAIN THREAT BEING GUSTY
WINDS TO AROUND 30 KNOTS. WINDS AT KAPA WILL MAINLY BE FROM THE
SOUTH...WHILE KDEN WILL BE EAST TO SOUTHEAST. A WEAK DENVER
CYCLONE PRODUCED A LIGHT THIS MORNING AND MAY AGAIN LATE TONIGHT
AND WEDNESDAY MORNING.
&&
.HYDROLOGY...
ISSUED AT 419 AM MDT TUE MAY 12 2015
MAIN CREST ON THE SOUTH PLATTE IS MOVING INTO MORGAN COUNTY...WITH
A SERIES OF SMALLER RISES PRECEDING IT. LITTLE CHANGE TO THE RIVER
FORECAST AS MODERATE TO MAJOR FLOODING IS EXPECTED DOWNSTREAM TO
STERLING THROUGH FRIDAY...AND MINOR TO MODERATE FLOODING BETWEEN
STERLING AND JULESBURG THIS WEEKEND.
WE WILL NEED TO WATCH ANY ADDITIONAL RAINFALL...THE FIRST
OPPORTUNITY IS WEDNESDAY AFTERNOON AND EVENING WHICH LOOKS
LIGHT OVERALL BUT THERE COULD BE SOME LOCALIZED HEAVIER
RAIN OF UP TO AN INCH. THAT WOULD EXACERBATE LOCAL PROBLEMS...
BUT PROBABLY NOT MUCH INFLUENCE ON THE PLATTE FLOODING. THERE MAY
BE BETTER COVERAGE OF THUNDERSTORMS WITH ADDITIONAL RAINFALL OVER
THE WEEKEND...NOT MUCH INDICATION OF ANY HEAVY RAINFALL HOWEVER.
CLOSER TO THE FRONT RANGE STREAMS WILL REMAIN HIGH INDEFINITELY WITH
SATURATED SOILS AND INCREASING SNOWMELT WITH THE WARMER TEMPERATURES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MEIER
SHORT TERM...GIMMESTAD
LONG TERM...BOWEN
AVIATION...MEIER
HYDROLOGY...GIMMESTAD
AREA FORECAST DISCUSSION
NWS TAUNTON MA
152 AM EDT TUE MAY 12 2015
.SYNOPSIS...
ANOTHER MILD AND HUMID NIGHT WITH DENSE FOG TONIGHT GIVES WAY TO
ANOTHER WARM DAY WITH SOME SHOWERS AND THUNDERSTORMS POSSIBLE IN
THE AFTERNOON AS THE REMNANTS OF ANA PASS BY. LARGE HIGH PRESSURE
WILL BUILD ACROSS THE EASTERN U.S. WITH DRIER WEATHER THROUGH THE
REMAINDER OF THE WEEK. AN APPROACHING WARM FRONT COULD BRING
SCATTERED SHOWERS NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
150 AM UPDATE...
A FEW SHOWERS HAVE DEVELOPED ACROSS NE CT THROUGH SE MA EARLY
THIS MORNING. ADDITIONAL SHOWERS S OF LONG ISLAND ASSOCD WITH ANA
REMNANTS WILL BE LIFTING N ACROSS THE COASTAL PLAIN THROUGH
DAYBREAK. AN ISOLD TSTM IS POSSIBLE AS ELEVATED INSTABILITY
PARAMETERS ARE MARGINAL.
CONVECTIVE LINE MOVING THROUGH CENTRAL NY IS EXPECTED TO REMAIN
WEST OF SNE THROUGH DAYBREAK.
PREVIOUS DISCUSSION...
BACKDOOR FRONT APPEARS TO HAVE STALLED FROM NE RI THROUGH
PORTIONS OF SE MA. TEMPS IN THE 50S TO THE N AND E OF THE FRONT
AND MAINLY 60S JUST TO THE S AND W. AS REMNANTS OF ANA APPROACHES
LATE TONIGHT...HI-RES GUIDANCE LIFTS THE FRONT BACK TO THE N
OVERNIGHT ACROSS RI AND SE MA.
AREAS OF DENSE FOG HAVE OVERSPREAD THE IMMEDIATE S COAST THIS
EVENING. WITH LOW LEVEL S/SW FLOW EXPECT DENSE FOG THREAT WILL BE
CONFINED TO THE S COAST AND SE MA...AND ALONG NE MA COAST WHERE
WINDS ARE EASTERLY. LATEST HRRR HAS LOWEST VSBYS ALONG THE S AND E
COASTS SO WE TRIMMED THE DENSE FOG ADVISORY AWAY FROM THE COAST.
FINALLY...HAVE INCREASED POPS ACROSS SE COASTAL MA AND CAPE COD
FOR LATE TONIGHT AS REMNANTS OF ANA TRACK TO THE SOUTH. MODELS
SHOW AREA OF DEEPER MOISTURE ALONG WITH SOME ELEVATED INSTABILITY
AT THE NOSE OF A LOW LEVEL JET WHICH SHOULD BRING AN AREA OF
SHOWERS OR AN ISOLD TSTM TO SE COASTAL NEW ENG. LATEST RAP SHOWS
AN AREA OF MEASURABLE RAINFALL LATE TONIGHT OVERSPREADING
PORTIONS OF RI AND SE MA.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
TOMORROW...
THE EARLY MORNING WILL BE MARKED BY A FAIRLY ROBUST DECK OF LOW
LVL CLOUDS AND FOG POSSIBLY AS FAR WEST AS THE CT VALLEY. THIS
WILL TAKE SOME TIME TO BURN OFF DURING THE MORNING AS DIURNAL
MIXING COMMENCES. EXACTLY HOW QUICKLY WILL DETERMINE THE THREAT
FOR CONVECTION/SEVERITY AS A COLD FRONT APPROACHES FOR THE
AFTERNOON.
BY AFTERNOON...AS THE FRONT MAKES IT/S PASS/APPROACH...SOME BREAKS
OF SUN ARE LIKELY ESPECIALLY FOR INTERIOR NRN MA AND WRN CT. THIS
AREA WILL BE THE PLACE TO WATCH AS BUFKIT PROFILES SHOW MODEST
CAPE VALUES APPROACHING 1000-1500 J/KG COMBINED WITH ABOUT 30 KT
OF 0-3KM SHEAR. UPPER LVL PROFILES WILL BE DRYING HOWEVER RATHER
QUICKLY SO IT/S A RACE AGAINST TIME AS TO WHETHER THE DRY AIR OR
INSTABILITY WINS AS THE LOW LVL F-GEN SOURCE APPROACHES. HI-RES
AND EVEN MORE COARSE GUIDANCE ALL SHOWING THE POSSIBILITY OF
AFTERNOON CONVECTIVE ACTIVITY WITH THE FROPA...ESPECIALLY NRN
INTERIOR MA AWAY FROM WHERE THE LOW LVL CLOUDS WILL HOLD IN.
SLIGHT CHANCE OF A STRONG STORM GIVEN THE MODEST SHEAR
VALUES...WHICH COINCIDES WELL WITH THE 18Z DAY TWO SWODY FROM
SPC...WHICH HIGHLIGHTS A MARGINAL RISK. THERE WILL STILL BE SOME
LEFTOVER LOW-LVL MOISTURE FROM ANA AHEAD OF THE FRONT...SO WILL
ALSO NEED TO WATCH FOR HEAVIER RAIN.
OTHER ISSUES FOR TOMORROW...
FIRE WEATHER CONCERNS...
AREAS WHERE THE CLOUD DISSIPATE WILL SEE LOW RELATIVE RH VALUES
AND GIVEN DIURNAL MIXING...WIND GUSTS OF 25-30 MPH AT TIMES.
THEREFORE...HAVE A MARGINAL RISK OF ELEVATED FIRE WEATHER DURING
THE DAY IN SPITE OF THE T-STORM/SHRA POTENTIAL. FOR MORE ON
THIS...SEE THE FIRE WEATHER SECTION BELOW.
HIGH SURF...
THE REMNANTS OF ANA WILL BRING 6 TO 10 FOOT SWELL TO OUR SOUTHERN
COASTAL WATERS TOMORROW. THIS WILL BRING HIGH SURF AND DANGEROUS
RIP CURRENTS TO OUR OCEAN EXPOSED SOUTH FACING BEACHES ON TUE.
GIVEN RELATIVELY WARM TEMPS EXPECTED...WE MAY STILL HAVE TO
CONSIDER A HIGH SURF ADVISORY EVEN THOUGH THE SUMMER SEASON HAS
NOT OFFICIAL BEGUN.
TUESDAY NIGHT...
FINALLY...THE HIGHER DWPTS...DRIER AIR AND IMPROVING CONDITIONS
WILL BE MOVING ACROSS THE REGION FROM W-E DURING THE OVERNIGHT
HOURS. LEFTOVER TSRA/SHRA WILL GENERALLY DIMINISH WITH THE LOSS OF
DIURNAL HEATING...SO THERE MAY BE A FEW CLOUDS STILL TO CONTEND
WITH EARLY. GIVEN THE MASS FIELDS ALSO SUPPORT A MODERATE PRES
GRADIENT...TEMPS ARE NOT LIKELY TO FALL AS LOW AS THEIR POTENTIAL
DESPITE THE DROPPING DWPTS. MINS MAINLY IN THE MID 40S AND LOW
50S.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
HIGHLIGHTS...
* BREAK IN THE HEAT ON WEDNESDAY WITH NORMAL TEMPS
* HIGH PRESSURE ON THURS & FRI KEEP CONDITIONS DRY
* RAIN RELIEF POSSIBLE OVER THE WEEKEND WITH APPROACHING LOW
OVERVIEW...
FORECAST GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT FOR MOST OF THE
EXTENDED. NOTICED 11.12Z GUIDANCE LEANED TOWARDS THE 11.00Z GFS FROM
LAST NIGHT IN BRINGING PRECIP INTO THE REGION FOR THE WEEKEND.
OTHERWISE BY LATE WEEKEND INTO EARLY NEXT WEEK APPEARS THAT THE EC
IS MORE AMPLIFIED IN BUILDING A STOUT RIDGE OVER NEW ENGLAND
COMPARED TO THE GFS. THIS COULD MAKE THINGS LESS STORMY THEN
PREVIOUSLY THOUGHT. APPEARS TEMPS WILL LEAN MORE TOWARDS OR JUST
ABOVE NORMAL OVER THE LONG TERM. COULD SEE AN INCREASE IN THE HEAT
BY NEXT WEEK.
DETAILS...
* WEDNESDAY...HIGH CONFIDENCE.
SECONDARY COLD FRONT WILL PASS THROUGH THE REGION PUSHING UPPER LEVEL
TROUGH OFFSHORE AND TEMPS ALOFT TO COOL OVER THE AREA. WINDS WILL
SWITCH TO A MORE NW FLOW...ALLOWING FOR GOOD DOWNSLOPING. PARTLY
SUNNY SKIES WILL ALLOW FOR TEMPS TO WARM INTO THE UPPER 60S...WHICH
IS NEAR NORMAL! DID LOWER DEWPOINTS AND INCREASE WIND GUSTS VERSUS
GUIDANCE AS MIXING ON WED WILL BE VERY GOOD. THIS WILL BRING A RISK
OF FIRE WEATHER CONCERNS TO THE REGION. DETAILS IN THE FIRE WEATHER
SECTION BELOW.
BECAUSE OF THE FALLING TEMPS ALOFT AND MARGINAL MOISTURE FIELD...
HAVE INSERTED A LOW CHANCE FOR AN ISOLATED SHOWER FOR FRANKLIN
COUNTY. CONFIDENCE IS LOW...BUT CANNOT RULE IT OUT.
TEMPS ALOFT WILL DROP THROUGHOUT THE DAY AND INTO THE OVERNIGHT
HOURS. IN FACT 850MB COULD DROP DOWN TO 0C OVERNIGHT. THIS COMBINED
WITH CLEAR SKIES AND DECOUPLE WINDS WILL ALLOW FOR RADIATIONAL
COOLING OVERNIGHT. TEMPS WILL DROP INTO THE LOWER 40S. COULD SEE A
FEW UPPER 30S BUT HAVE A LOW CONFIDENCE ON FROST DEVELOPMENT IN THE
VALLEY LOCALS ACROSS THE NW PORTION OF THE AREA.
* THURSDAY AND FRIDAY...HIGH CONFIDENCE.
HIGH PRESSURE WILL MOVE RIGHT ON IN FOR THURSDAY AND LAST INTO
FRIDAY. THIS WILL ALLOW FOR DRY WEATHER AND PLENTY OF SUNSHINE. HAVE
AN INCREASE CHANCE THAT SEA BREEZES WILL DEVELOP ACROSS THE
COASTLINES FOR BOTH DAYS. TEMPERATURES WILL WARM ABOVE AVERAGE ONCE
AGAIN...WITH HIGHS IN THE LOW 70S ON THURSDAY AND MID 70S ON FRIDAY
AWAY FROM THE COASTLINES.
* THE WEEKEND...MODERATE CONFIDENCE.
HIGH PRESSURE WILL MOVE SOUTH AND OFFSHORE ALLOWING FOR APPROACHING
LOW PRESSURE FROM THE WEST TO PUSH A WARM FRONT OVER THE REGION.
DEPENDING ON WHERE THIS WARM FRONT SETS UP WE COULD SEE A FEW ROUNDS
OF SHOWERS AS A WAVE OR TWO MOVES THROUGH THE AREA. NOT EXPECTING A
DROUGHT BUSTER AS WE NEED ABOUT 3-5 INCHES...BUT SOME RAIN RELIEF TO
THE REGION IS ANTICIPATED.
* MONDAY...LOW CONFIDENCE.
MONDAY IS LOOKING WARM BUT STILL UNCERTAIN ON PRECIP CHANCES AS THE
PATTERN WILL BE FOCUSED ON IF THE RIDGE WILL BUILD OR NOT.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
THROUGH 12Z...WIDESPREAD IFR/LIFR CONDITIONS IN STRATUS AND
FOG...ALTHOUGH SOME MVFR IN THE CT VALLEY. DENSE FOG CONFINED TO
THE S COAST. SCT SHOWERS AND ISOLD TSTM NE CT THROUGH SE MA.
TODAY...MODERATE CONFIDENCE. IFR/LIFR STRATUS AND FOG WILL
IMPROVE TO VFR BY MIDDAY...BUT AREAS OF IFR WILL LIKELY PERSIST
ALONG THE IMMEDIATE S COAST AND ESPECIALLY THE ISLANDS INTO THE
AFTERNOON. CHANCE OF A FEW THUNDERSTORMS IN THE AFTERNOON. SW
GUSTS TO 25 KT POSSIBLE RI AND SE MA DURING THE AFTERNOON.
TONIGHT...MODERATE CONFIDENCE. MAINLY VFR...BUT IFR CONDITIONS
POSSIBLE INTO THE EVENING ACROSS OUTER CAPE/ISLANDS.
WEDNESDAY...HIGH CONFIDENCE. VFR CIGS. NW GUSTS TO 25 KT.
KBOS TAF...HIGH CONFIDENCE IN TRENDS. LOWER CONFIDENCE IN TIMING
OF IMPROVEMENT TO VFR.
KBDL TAF...HIGH CONFIDENCE IN TRENDS. LOWER CONFIDENCE IN TIMING
OF IMPROVEMENT TO VFR.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...HIGH CONFIDENCE.
THURSDAY-FRIDAY...VFR. LIGHT AND VARIABLE WINDS. SEA BREEZES
POSSIBLE ON BOTH DAYS.
SATURDAY...VFR/MVFR WITH AN INCREASE IN SHOWERS.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH TUESDAY NIGHT/...
TONIGHT INTO TOMORROW...MODERATE CONFIDENCE.
LEFTOVER SWELL FROM ANA WILL BEGIN TO BUILD ALONG THE S COASTAL
WATERS LATE. REACHING A PEAK OF ABOUT 7-9 FT BY THE MID DAY
TOMORROW. SMALL CRAFT ADVISORIES CONTINUE FOR THIS THREAT.
OTHERWISE...WINDS REMAIN GENERALLY OUT OF THE S-SW UNTIL A COLD
FRONTAL PASSAGE TOMORROW LATE IN THE DAY...AT WHICH POINT THEY
SHIFT W.
THERE IS THE LOW THREAT FOR SOME THUNDERSTORMS...MAINLY ACROSS THE
E WATERS LATE IN THE DAY TOMORROW. FOG/STRATUS WILL ONCE AGAIN
YIELD NEAR ZERO VSBYS ACROSS THE WATERS TONIGHT INTO TOMORROW.
TOMORROW NIGHT...HIGH CONFIDENCE.
SLOW IMPROVEMENT AS WINDS SHIFT TO THE W. ANY SHOWERS/STORMS WILL
END AND SCOUR OUT THE LEFTOVER FOG. SEAS WILL ALSO GRADUALLY
DECLINE SUCH THAT SMALL CRAFT ADVISORIES MAY BE DROPPED BY THE
EARLY MORNING HOURS.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...MODERATE CONFIDENCE.
WEDNESDAY...LINGERING 5FT SEAS WILL CONTINUE ON WED. HOWEVER GUSTS
WILL BE ON THE INCREASE TO 25 KTS ESP ACROSS THE INTERIOR
WATERS...SCA WILL BE NEEDED.
THURSDAY-FRIDAY...HIGH PRESSURE BUILDS OVER THE WATERS. WINDS AND
SEAS WILL BE BELOW SMALL CRAFT CRITERIA.
SATURDAY...WARM FRONT WILL PUSH OVER THE WATERS INCREASING PRECIP
CHANCES. BUT BOTH WINDS AND SEAS WILL REMAIN BELOW SCA.
&&
.FIRE WEATHER...
TOMORROW...TEMPERATURES MAY RISE TO NEAR 90 IN THE LOWER CT
VALLEY OF MA AND CT WITH DWPTS HOLDING IN THE 50S AND 60S. THERE
IS THE POSSIBILITY THEREFORE...THAT MIN RH VALUES WILL FALL TO
AROUND 25-35 PERCENT IN PORTIONS OF SW MA DURING THE DAY. SW WINDS
WILL GUST 25-30 MPH AT TIMES BY THE AFTERNOON. ALSO...THERE IS THE
THREAT FOR THUNDERSTORMS AND ACCUMULATING RAINFALL...BUT THESE
WILL GENERALLY BE HIT OR MISS AND WILL NOT PROVIDE THE WIDESPREAD
RAINFALL THAT MUCH OF THE REGION REQUIRES. A FIRE WEATHER WATCH
WILL BE ISSUED FOR SW PORTIONS OF MA DUE TO THE COLLOCATION OF
DRIEST RH VALUES...HIGHEST WINDS AND LOWEST THREAT FOR RAINFALL.
WEDNESDAY...A HIGHER RISK FOR FIRE WEATHER DEVELOPMENT IS EXPECTED
ON WEDNESDAY...HOWEVER IT WILL BE DEPENDENT ON PRECIP CHANCES OVER
THE NEXT 24-48 HOURS. SECONDARY COLD FRONT WILL PUSH THROUGH WED
MORNING ALLOWING FOR WINDS TO BE MORE OUT OF THE NW. THIS WILL
ALLOW FOR A DOWNSLOPING EFFECT...WHICH WILL INCREASE THE WIND
GUSTS AND LOWER DEWPOINTS. RIGHT NOW BELIEVE THAT RH VALUES WILL
DROP TO AROUND 30 PERCENT ACROSS MUCH OF THE REGION WITH NW WINDS
GUSTING TO NEAR 30 MPH. ONLY DIFFERENCE COMPARED TO THE PREVIOUS
DAYS IS HIGH TEMPS WILL WARM ONLY INTO THE UPPER 60S. HOWEVER
APPEARS THAT THERE WILL BE A GOOD AMOUNT OF SUNSHINE ACROSS MOST
OF THE REGION. WILL NEED TO CONTINUE TO MONITOR WEDNESDAY FOR
POSSIBLE HEADLINES.
THURSDAY AND FRIDAY...DRY WEATHER CONDITIONS WILL CONTINUE WITH RH
VALUES DROPPING WELL INTO THE 20 PERCENT LEVEL AND WITH FULL
SHINE. SINCE HIGH PRESSURE WILL BE OVERHEAD WIND WILL BE LIGHT AND
VARIABLE...GUSTS COULD REACH 10-15 MPH.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR MAZ018>024.
FIRE WEATHER WATCH FROM NOON EDT TODAY THROUGH THIS EVENING
FOR MAZ008>012.
RI...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR RIZ005>008.
MARINE...SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 8 PM EDT THIS
EVENING FOR ANZ235-237.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
ANZ254>256.
&&
$$
SYNOPSIS...DOODY/DUNTEN
NEAR TERM...KJC
SHORT TERM...DOODY
LONG TERM...DUNTEN
AVIATION...KJC/DUNTEN
MARINE...DOODY/DUNTEN
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1222 PM CDT TUE MAY 12 2015
.UPDATE...
ISSUED AT 943 AM CDT TUE MAY 12 2015
MAIN STRATOCUMULUS SHIELD BASICALLY MADE IT DOWN TO THE I-74
CORRIDOR WITH SOME SCATTERED CLOUDS AS FAR SOUTH AS MATTOON AND
LAWRENCEVILLE...BUT THESE SHOULD CONTINUE TO PULL BACK NORTHWARD
THROUGH MIDDAY. HOWEVER...LATEST RAP GUIDANCE SUGGESTS THE CLOUDS
HOLDING ON A BIT LONGER AROUND CHAMPAIGN AND DANVILLE. CURRENTLY
SEEING SOME WIND GUSTS OF 25-30 MPH...WHICH SHOULD CONTINUE INTO
MID AFTERNOON. TEMPERATURES CURRENTLY ON TRACK AND ONLY REQUIRED
SOME MINOR TWEAKS. UPDATES TO THE ZONES/GRIDS WERE MAINLY DONE FOR
THE SKY COVER AND WIND TRENDS.
&&
.SHORT TERM...(TODAY)
ISSUED AT 329 AM CDT TUE MAY 12 2015
07Z/2AM SURFACE ANALYSIS SHOWS 1001MB LOW OVER THE NORTHERN GREAT
LAKES WHILE A 1025MB HIGH BUILDS INTO THE CENTRAL PLAINS. PRESSURE
GRADIENT BETWEEN THESE TWO FEATURES WILL REMAIN TIGHT ENOUGH TO
PRODUCE BRISK WESTERLY WINDS ACROSS CENTRAL ILLINOIS TODAY.
SUSTAINED WINDS WILL GENERALLY BE IN THE 10 TO 15 MPH RANGE...BUT
GUSTS COULD REACH 25 TO 30 MPH AS MIXING TAKES PLACE LATER THIS
MORNING. LATEST VWP NETWORK SHOWS 925MB WINDS OF 40 TO 45 MPH AND
THINK SOME OF THIS HIGHER MOMENTUM AIR WILL GET MIXED DOWN TO THE
SURFACE ONCE MORNING INVERSION IS BROKEN. PRESSURE GRADIENT WILL
TEND TO RELAX AS THE DAY PROGRESSES...SO GUSTS WILL BEGIN TO SLOWLY
SUBSIDE BY MID-AFTERNOON. LOW CLOUDS CURRENTLY ALONG/NORTH OF A
RUSHVILLE TO BLOOMINGTON LINE WILL LIFT NORTHEASTWARD AND CLEAR OUT
OF THE AREA BY MID-MORNING...FOLLOWED BY MOSTLY SUNNY SKIES ACROSS
THE BOARD FOR THE REMAINDER OF THE DAY. AFTERNOON HIGH TEMPERATURES
WILL BE SEVERAL DEGREES COOLER THAN IN RECENT DAYS...WITH READINGS
ONLY RISING INTO THE LOWER TO MIDDLE 60S.
.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 329 AM CDT TUE MAY 12 2015
HIGH PRESSURE WILL BUILD EASTWARD INTO THE MIDWEST TONIGHT...WITH
THE RIDGE AXIS EXPECTED TO BE POSITIONED RIGHT OVER ILLINOIS BY 12Z
WED. CLEAR SKIES AND LIGHT WINDS BENEATH THE RIDGE WILL ALLOW
EXCELLENT RADIATIONAL COOLING OF THE DRY AIRMASS TO TAKE
PLACE...RESULTING IN OVERNIGHT LOW TEMPERATURES IN THE LOWER TO
MIDDLE 40S. MAY EVEN SEE A FEW UPPER 30S IN FAVORED LOW-LYING
RURAL AREAS. THE HIGH WILL BEGIN TO SHIFT OFF TO THE EAST ON
WEDNESDAY...HOWEVER LOW-LEVEL FLOW WILL MAINTAIN A DISTINCT
EASTERLY COMPONENT. AS A RESULT...HIGH TEMPERATURES WILL REMAIN ON
THE COOL SIDE IN THE UPPER 60S TO AROUND 70 DEGREES.
UPPER HEIGHTS BEGIN TO RISE SIGNIFICANTLY BY THURSDAY AS DEEP UPPER
LOW OVER THE GULF OF ALASKA DROPS SOUTHEASTWARD AND REACHES THE
CALIFORNIA COAST...RESULTING IN DOWNSTREAM RIDGING ACROSS THE
CENTRAL AND EASTERN CONUS. A WEAK DISTURBANCE NOTED ON LATEST WATER
VAPOR IMAGERY OFF THE COAST OF SOUTHERN CALIFORNIA WILL GET EJECTED
NORTHEASTWARD BY THE DIGGING WEST COAST TROUGH...WITH THIS FEATURE
TRACKING INTO THE GREAT LAKES BY FRIDAY. MODELS ARE IN GOOD
AGREEMENT WITH THE TRACK AND TIMING OF THIS WAVE...WITH SOME MINOR
DISCREPANCIES ON HOW QUICKLY TO SPREAD PRECIP INTO ILLINOIS. GIVEN
INITIALLY VERY DRY AIRMASS IN PLACE BENEATH THE SURFACE
HIGH...PREFER A SLOWER ARRIVAL OF PRECIP. AS A RESULT...HAVE GONE
WITH A DRY FORECAST THROUGH THURSDAY MORNING EAST OF I-55 WITH LOW
CHANCE POPS DELAYED UNTIL AFTERNOON. FURTHER WEST...RAIN CHANCES
WILL INCREASE TO LIKELY ACROSS THE ILLINOIS RIVER VALLEY BY
AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS WILL SPREAD ACROSS
MUCH OF THE AREA THURSDAY NIGHT...WITH THE BEST RAIN CHANCES FOCUSED
NORTH OF THE I-70 CORRIDOR. ONCE THE SHORT-WAVE SHIFTS INTO THE
GREAT LAKES...FORCING FOR ADDITIONAL PRECIP BECOMES MUCH WEAKER
FRIDAY AND SATURDAY. SEVERAL MODELS ARE HINTING THAT ANOTHER
WEAK WAVE EMBEDDED WITHIN THE SOUTHWESTERLY FLOW MAY ENHANCE
SHOWERS ACROSS SOUTHERN ILLINOIS INTO THE OHIO RIVER
VALLEY...HOWEVER VERY LITTLE FOCUS FOR ORGANIZED CONVECTION EXISTS
FURTHER NORTH ACROSS THE REMAINDER OF THE AREA. AS A
RESULT...WILL ONLY CARRY LOW CHANCE POPS THROUGH THE PERIOD.
DEEP UPPER LOW OVER CALIFORNIA WILL GRADUALLY EJECT NORTHEASTWARD
LATE IN THE WEEKEND. MODELS ARE IN GOOD AGREEMENT WITH THIS PROCESS
THROUGH 144 HOURS...THEN SOLUTIONS BEGIN TO DIVERGE AFTER THAT.
BOTH THE GFS AND ECMWF SHOW THE LOW TRACKING INTO THE DAKOTAS BY
SUNDAY EVENING...WITH CONVECTION DEVELOPING ALONG A TRAILING COLD
FRONT ACROSS THE PLAINS. THE ECMWF THEN BECOMES MORE PROGRESSIVE
WITH THE WAVE...AS IT OPENS UP AND PUSHES EASTWARD INTO THE NORTHERN
GREAT LAKES BY MONDAY. MEANWHILE...THE GFS KEEPS THE LOW CLOSED
LONGER AND IS THUS SLOWER WITH ITS EASTWARD TRACK. THIS MAKES A BIG
DIFFERENCE WITH TIMING OF ASSOCIATED COLD FRONT...AS GFS LINGERS
THIS BOUNDARY AND RAIN CHANCES UNTIL TUESDAY. SINCE OVERALL
SYNOPTIC PATTERN HAS BEEN PROGRESSIVE OVER THE PAST WEEK AND THE GEM
SUPPORTS THE ECMWF...WILL BE GOING WITH THE FASTER ECMWF/GEM
SOLUTION IN THE EXTENDED. AS A RESULT...WILL BRING LIKELY POPS INTO
THE FAR WESTERN CWA SUNDAY AFTERNOON...THEN FURTHER EAST ACROSS THE
REMAINDER OF THE AREA SUNDAY NIGHT. WILL THEN BEGIN TO SHIFT THE
RAIN CHANCES OUT OF THE PICTURE ON MONDAY...WITH DRY WEATHER
RETURNING MONDAY NIGHT AND TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1219 PM CDT TUE MAY 12 2015
THICKER STRATOCUMULUS AROUND 3500 FEET CONTINUES TO BREAK UP AND
WILL BE MOST PROMINENT AT KCMI/KDEC FOR A COUPLE MORE HOURS.
OTHERWISE...GENERAL TREND WILL BE VFR WITH SOME INCREASE IN HIGH
CLOUDS LATER THIS AFTERNOON. GUSTY WEST/NORTHWEST WINDS AROUND 25
KNOTS SHOULD BE SETTLING DOWN AFTER ABOUT 23Z...AND WILL GRADUALLY
TURN MORE THE NORTH/NORTHEAST OVERNIGHT AS AN AREA OF HIGH
PRESSURE MOVES THROUGH THE MIDWEST. AS THE HIGH MOVES FURTHER EAST
WEDNESDAY MORNING...WINDS WILL BECOME MORE EASTERLY AND INCREASE
TO AROUND 10 KNOTS.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS LINCOLN IL
943 AM CDT TUE MAY 12 2015
.UPDATE...
ISSUED AT 943 AM CDT TUE MAY 12 2015
MAIN STRATOCUMULUS SHIELD BASICALLY MADE IT DOWN TO THE I-74
CORRIDOR WITH SOME SCATTERED CLOUDS AS FAR SOUTH AS MATTOON AND
LAWRENCEVILLE...BUT THESE SHOULD CONTINUE TO PULL BACK NORTHWARD
THROUGH MIDDAY. HOWEVER...LATEST RAP GUIDANCE SUGGESTS THE CLOUDS
HOLDING ON A BIT LONGER AROUND CHAMPAIGN AND DANVILLE. CURRENTLY
SEEING SOME WIND GUSTS OF 25-30 MPH...WHICH SHOULD CONTINUE INTO
MID AFTERNOON. TEMPERATURES CURRENTLY ON TRACK AND ONLY REQUIRED
SOME MINOR TWEAKS. UPDATES TO THE ZONES/GRIDS WERE MAINLY DONE FOR
THE SKY COVER AND WIND TRENDS.
&&
.SHORT TERM...(TODAY)
ISSUED AT 329 AM CDT TUE MAY 12 2015
07Z/2AM SURFACE ANALYSIS SHOWS 1001MB LOW OVER THE NORTHERN GREAT
LAKES WHILE A 1025MB HIGH BUILDS INTO THE CENTRAL PLAINS. PRESSURE
GRADIENT BETWEEN THESE TWO FEATURES WILL REMAIN TIGHT ENOUGH TO
PRODUCE BRISK WESTERLY WINDS ACROSS CENTRAL ILLINOIS TODAY.
SUSTAINED WINDS WILL GENERALLY BE IN THE 10 TO 15 MPH RANGE...BUT
GUSTS COULD REACH 25 TO 30 MPH AS MIXING TAKES PLACE LATER THIS
MORNING. LATEST VWP NETWORK SHOWS 925MB WINDS OF 40 TO 45 MPH AND
THINK SOME OF THIS HIGHER MOMENTUM AIR WILL GET MIXED DOWN TO THE
SURFACE ONCE MORNING INVERSION IS BROKEN. PRESSURE GRADIENT WILL
TEND TO RELAX AS THE DAY PROGRESSES...SO GUSTS WILL BEGIN TO SLOWLY
SUBSIDE BY MID-AFTERNOON. LOW CLOUDS CURRENTLY ALONG/NORTH OF A
RUSHVILLE TO BLOOMINGTON LINE WILL LIFT NORTHEASTWARD AND CLEAR OUT
OF THE AREA BY MID-MORNING...FOLLOWED BY MOSTLY SUNNY SKIES ACROSS
THE BOARD FOR THE REMAINDER OF THE DAY. AFTERNOON HIGH TEMPERATURES
WILL BE SEVERAL DEGREES COOLER THAN IN RECENT DAYS...WITH READINGS
ONLY RISING INTO THE LOWER TO MIDDLE 60S.
.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 329 AM CDT TUE MAY 12 2015
HIGH PRESSURE WILL BUILD EASTWARD INTO THE MIDWEST TONIGHT...WITH
THE RIDGE AXIS EXPECTED TO BE POSITIONED RIGHT OVER ILLINOIS BY 12Z
WED. CLEAR SKIES AND LIGHT WINDS BENEATH THE RIDGE WILL ALLOW
EXCELLENT RADIATIONAL COOLING OF THE DRY AIRMASS TO TAKE
PLACE...RESULTING IN OVERNIGHT LOW TEMPERATURES IN THE LOWER TO
MIDDLE 40S. MAY EVEN SEE A FEW UPPER 30S IN FAVORED LOW-LYING
RURAL AREAS. THE HIGH WILL BEGIN TO SHIFT OFF TO THE EAST ON
WEDNESDAY...HOWEVER LOW-LEVEL FLOW WILL MAINTAIN A DISTINCT
EASTERLY COMPONENT. AS A RESULT...HIGH TEMPERATURES WILL REMAIN ON
THE COOL SIDE IN THE UPPER 60S TO AROUND 70 DEGREES.
UPPER HEIGHTS BEGIN TO RISE SIGNIFICANTLY BY THURSDAY AS DEEP UPPER
LOW OVER THE GULF OF ALASKA DROPS SOUTHEASTWARD AND REACHES THE
CALIFORNIA COAST...RESULTING IN DOWNSTREAM RIDGING ACROSS THE
CENTRAL AND EASTERN CONUS. A WEAK DISTURBANCE NOTED ON LATEST WATER
VAPOR IMAGERY OFF THE COAST OF SOUTHERN CALIFORNIA WILL GET EJECTED
NORTHEASTWARD BY THE DIGGING WEST COAST TROUGH...WITH THIS FEATURE
TRACKING INTO THE GREAT LAKES BY FRIDAY. MODELS ARE IN GOOD
AGREEMENT WITH THE TRACK AND TIMING OF THIS WAVE...WITH SOME MINOR
DISCREPANCIES ON HOW QUICKLY TO SPREAD PRECIP INTO ILLINOIS. GIVEN
INITIALLY VERY DRY AIRMASS IN PLACE BENEATH THE SURFACE
HIGH...PREFER A SLOWER ARRIVAL OF PRECIP. AS A RESULT...HAVE GONE
WITH A DRY FORECAST THROUGH THURSDAY MORNING EAST OF I-55 WITH LOW
CHANCE POPS DELAYED UNTIL AFTERNOON. FURTHER WEST...RAIN CHANCES
WILL INCREASE TO LIKELY ACROSS THE ILLINOIS RIVER VALLEY BY
AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS WILL SPREAD ACROSS
MUCH OF THE AREA THURSDAY NIGHT...WITH THE BEST RAIN CHANCES FOCUSED
NORTH OF THE I-70 CORRIDOR. ONCE THE SHORT-WAVE SHIFTS INTO THE
GREAT LAKES...FORCING FOR ADDITIONAL PRECIP BECOMES MUCH WEAKER
FRIDAY AND SATURDAY. SEVERAL MODELS ARE HINTING THAT ANOTHER
WEAK WAVE EMBEDDED WITHIN THE SOUTHWESTERLY FLOW MAY ENHANCE
SHOWERS ACROSS SOUTHERN ILLINOIS INTO THE OHIO RIVER
VALLEY...HOWEVER VERY LITTLE FOCUS FOR ORGANIZED CONVECTION EXISTS
FURTHER NORTH ACROSS THE REMAINDER OF THE AREA. AS A
RESULT...WILL ONLY CARRY LOW CHANCE POPS THROUGH THE PERIOD.
DEEP UPPER LOW OVER CALIFORNIA WILL GRADUALLY EJECT NORTHEASTWARD
LATE IN THE WEEKEND. MODELS ARE IN GOOD AGREEMENT WITH THIS PROCESS
THROUGH 144 HOURS...THEN SOLUTIONS BEGIN TO DIVERGE AFTER THAT.
BOTH THE GFS AND ECMWF SHOW THE LOW TRACKING INTO THE DAKOTAS BY
SUNDAY EVENING...WITH CONVECTION DEVELOPING ALONG A TRAILING COLD
FRONT ACROSS THE PLAINS. THE ECMWF THEN BECOMES MORE PROGRESSIVE
WITH THE WAVE...AS IT OPENS UP AND PUSHES EASTWARD INTO THE NORTHERN
GREAT LAKES BY MONDAY. MEANWHILE...THE GFS KEEPS THE LOW CLOSED
LONGER AND IS THUS SLOWER WITH ITS EASTWARD TRACK. THIS MAKES A BIG
DIFFERENCE WITH TIMING OF ASSOCIATED COLD FRONT...AS GFS LINGERS
THIS BOUNDARY AND RAIN CHANCES UNTIL TUESDAY. SINCE OVERALL
SYNOPTIC PATTERN HAS BEEN PROGRESSIVE OVER THE PAST WEEK AND THE GEM
SUPPORTS THE ECMWF...WILL BE GOING WITH THE FASTER ECMWF/GEM
SOLUTION IN THE EXTENDED. AS A RESULT...WILL BRING LIKELY POPS INTO
THE FAR WESTERN CWA SUNDAY AFTERNOON...THEN FURTHER EAST ACROSS THE
REMAINDER OF THE AREA SUNDAY NIGHT. WILL THEN BEGIN TO SHIFT THE
RAIN CHANCES OUT OF THE PICTURE ON MONDAY...WITH DRY WEATHER
RETURNING MONDAY NIGHT AND TUESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 600 AM CDT TUE MAY 12 2015
VFR CIGS EXPECTED TO PUSH OFF TO OUR EAST THIS MORNING BASED ON
CURRENT TRENDS IN SATELLITE DATA AND LATEST FORECAST SOUNDINGS.
CIG BASES HAVE BEEN FROM 3500 TO 4500 FEET WITH SOME LOWER...MVFR
CIGS...NOTED TO OUR NORTHWEST AND NORTH. THOSE ARE EXPECTED TO
REMAIN JUST TO THE NORTH OF PIA AND BMI THIS MORNING. SPI...DEC
AND CMI HAVE BEEN RIGHT ON THE EDGE OF THE VFR CIGS AND EXPECT
THOSE AREAS TO SEE SOME SCT-BKN CIGS FOR A TIME THIS MORNING WITH
THE MAIN AREA OF OVR CIGS TO THE NORTH.
GUSTY WINDS WILL CONTINUE TODAY WITH FORECAST SOUNDINGS SUGGESTING
WIND GUSTS TO AROUND 25 KTS AT TIMES OUT OF THE WEST AND THEN
NORTHWEST THIS AFTERNOON. LOOK FOR THE WINDS TO RAPIDLY DIMINISH
JUST AFTER SUNSET AS HIGH PRESSURE SETTLES IN OVERNIGHT WITH VFR
CONDITIONS CONTINUING.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS LINCOLN IL
329 AM CDT TUE MAY 12 2015
.SHORT TERM...(TODAY)
ISSUED AT 329 AM CDT TUE MAY 12 2015
07Z/2AM SURFACE ANALYSIS SHOWS 1001MB LOW OVER THE NORTHERN GREAT
LAKES WHILE A 1025MB HIGH BUILDS INTO THE CENTRAL PLAINS. PRESSURE
GRADIENT BETWEEN THESE TWO FEATURES WILL REMAIN TIGHT ENOUGH TO
PRODUCE BRISK WESTERLY WINDS ACROSS CENTRAL ILLINOIS TODAY.
SUSTAINED WINDS WILL GENERALLY BE IN THE 10 TO 15 MPH RANGE...BUT
GUSTS COULD REACH 25 TO 30 MPH AS MIXING TAKES PLACE LATER THIS
MORNING. LATEST VWP NETWORK SHOWS 925MB WINDS OF 40 TO 45 MPH AND
THINK SOME OF THIS HIGHER MOMENTUM AIR WILL GET MIXED DOWN TO THE
SURFACE ONCE MORNING INVERSION IS BROKEN. PRESSURE GRADIENT WILL
TEND TO RELAX AS THE DAY PROGRESSES...SO GUSTS WILL BEGIN TO SLOWLY
SUBSIDE BY MID-AFTERNOON. LOW CLOUDS CURRENTLY ALONG/NORTH OF A
RUSHVILLE TO BLOOMINGTON LINE WILL LIFT NORTHEASTWARD AND CLEAR OUT
OF THE AREA BY MID-MORNING...FOLLOWED BY MOSTLY SUNNY SKIES ACROSS
THE BOARD FOR THE REMAINDER OF THE DAY. AFTERNOON HIGH TEMPERATURES
WILL BE SEVERAL DEGREES COOLER THAN IN RECENT DAYS...WITH READINGS
ONLY RISING INTO THE LOWER TO MIDDLE 60S.
&&
.LONG TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 329 AM CDT TUE MAY 12 2015
HIGH PRESSURE WILL BUILD EASTWARD INTO THE MIDWEST TONIGHT...WITH
THE RIDGE AXIS EXPECTED TO BE POSITIONED RIGHT OVER ILLINOIS BY 12Z
WED. CLEAR SKIES AND LIGHT WINDS BENEATH THE RIDGE WILL ALLOW
EXCELLENT RADIATIONAL COOLING OF THE DRY AIRMASS TO TAKE
PLACE...RESULTING IN OVERNIGHT LOW TEMPERATURES IN THE LOWER TO
MIDDLE 40S. MAY EVEN SEE A FEW UPPER 30S IN FAVORED LOW-LYING
RURAL AREAS. THE HIGH WILL BEGIN TO SHIFT OFF TO THE EAST ON
WEDNESDAY...HOWEVER LOW-LEVEL FLOW WILL MAINTAIN A DISTINCT
EASTERLY COMPONENT. AS A RESULT...HIGH TEMPERATURES WILL REMAIN ON
THE COOL SIDE IN THE UPPER 60S TO AROUND 70 DEGREES.
UPPER HEIGHTS BEGIN TO RISE SIGNIFICANTLY BY THURSDAY AS DEEP UPPER
LOW OVER THE GULF OF ALASKA DROPS SOUTHEASTWARD AND REACHES THE
CALIFORNIA COAST...RESULTING IN DOWNSTREAM RIDGING ACROSS THE
CENTRAL AND EASTERN CONUS. A WEAK DISTURBANCE NOTED ON LATEST WATER
VAPOR IMAGERY OFF THE COAST OF SOUTHERN CALIFORNIA WILL GET EJECTED
NORTHEASTWARD BY THE DIGGING WEST COAST TROUGH...WITH THIS FEATURE
TRACKING INTO THE GREAT LAKES BY FRIDAY. MODELS ARE IN GOOD
AGREEMENT WITH THE TRACK AND TIMING OF THIS WAVE...WITH SOME MINOR
DISCREPANCIES ON HOW QUICKLY TO SPREAD PRECIP INTO ILLINOIS. GIVEN
INITIALLY VERY DRY AIRMASS IN PLACE BENEATH THE SURFACE
HIGH...PREFER A SLOWER ARRIVAL OF PRECIP. AS A RESULT...HAVE GONE
WITH A DRY FORECAST THROUGH THURSDAY MORNING EAST OF I-55 WITH LOW
CHANCE POPS DELAYED UNTIL AFTERNOON. FURTHER WEST...RAIN CHANCES
WILL INCREASE TO LIKELY ACROSS THE ILLINOIS RIVER VALLEY BY
AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS WILL SPREAD ACROSS
MUCH OF THE AREA THURSDAY NIGHT...WITH THE BEST RAIN CHANCES FOCUSED
NORTH OF THE I-70 CORRIDOR. ONCE THE SHORT-WAVE SHIFTS INTO THE
GREAT LAKES...FORCING FOR ADDITIONAL PRECIP BECOMES MUCH WEAKER
FRIDAY AND SATURDAY. SEVERAL MODELS ARE HINTING THAT ANOTHER
WEAK WAVE EMBEDDED WITHIN THE SOUTHWESTERLY FLOW MAY ENHANCE
SHOWERS ACROSS SOUTHERN ILLINOIS INTO THE OHIO RIVER
VALLEY...HOWEVER VERY LITTLE FOCUS FOR ORGANIZED CONVECTION EXISTS
FURTHER NORTH ACROSS THE REMAINDER OF THE AREA. AS A
RESULT...WILL ONLY CARRY LOW CHANCE POPS THROUGH THE PERIOD.
DEEP UPPER LOW OVER CALIFORNIA WILL GRADUALLY EJECT NORTHEASTWARD
LATE IN THE WEEKEND. MODELS ARE IN GOOD AGREEMENT WITH THIS PROCESS
THROUGH 144 HOURS...THEN SOLUTIONS BEGIN TO DIVERGE AFTER THAT.
BOTH THE GFS AND ECMWF SHOW THE LOW TRACKING INTO THE DAKOTAS BY
SUNDAY EVENING...WITH CONVECTION DEVELOPING ALONG A TRAILING COLD
FRONT ACROSS THE PLAINS. THE ECMWF THEN BECOMES MORE PROGRESSIVE
WITH THE WAVE...AS IT OPENS UP AND PUSHES EASTWARD INTO THE NORTHERN
GREAT LAKES BY MONDAY. MEANWHILE...THE GFS KEEPS THE LOW CLOSED
LONGER AND IS THUS SLOWER WITH ITS EASTWARD TRACK. THIS MAKES A BIG
DIFFERENCE WITH TIMING OF ASSOCIATED COLD FRONT...AS GFS LINGERS
THIS BOUNDARY AND RAIN CHANCES UNTIL TUESDAY. SINCE OVERALL
SYNOPTIC PATTERN HAS BEEN PROGRESSIVE OVER THE PAST WEEK AND THE GEM
SUPPORTS THE ECMWF...WILL BE GOING WITH THE FASTER ECMWF/GEM
SOLUTION IN THE EXTENDED. AS A RESULT...WILL BRING LIKELY POPS INTO
THE FAR WESTERN CWA SUNDAY AFTERNOON...THEN FURTHER EAST ACROSS THE
REMAINDER OF THE AREA SUNDAY NIGHT. WILL THEN BEGIN TO SHIFT THE
RAIN CHANCES OUT OF THE PICTURE ON MONDAY...WITH DRY WEATHER
RETURNING MONDAY NIGHT AND TUESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1154 PM CDT MON MAY 11 2015
VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES NEXT 24HRS. WRAP-
AROUND CLOUDS CONTINUE TO MOVE ACROSS THE NORTHERN THIRD OF THE
STATE WITH BROKEN TO OVERCAST CLOUDS OCCURRING AT PIA. THESE
CLOUDS SHOULD REACH BMI SO WILL HAVE BROKEN TO OVERCAST CLOUDS AT
BOTH SITES BUT HAVE A TEMPO GROUP FOR BMI FOR FIRST SEVERAL HOURS
OF TAF FOR SCATTERED CLOUDS. OTHER SITES WILL JUST SEE SCATTERED
CLOUDS OVERNIGHT AND THROUGH MOST OF THE DAY. HRRR MODEL SHOWS THE
POSSIBILITY OF SOME BROKEN CIGS REACHING CMI IN THE MORNING SO
WILL HAVE TEMPO GROUP TO COVER THAT IN THE MORNING. ALL SITES WILL
EITHER REMAIN SCATTERED OR SCATTER OUT DURING THE MORNING HOURS
AND THEN BECOME CLEAR LATE MORNING TO EVENING HOURS. WEST WINDS
WILL CONTINUE AND THEN BECOME NORTHWEST TOMORROW EVENING. GUSTY
WINDS ARE EXPECTED AGAIN TOMORROW.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...AUTEN
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1154 PM CDT MON MAY 11 2015
.UPDATE...
ISSUED AT 904 PM CDT MON MAY 11 2015
WRAP-AROUND CLOUDS CONTINUE TO SLOWLY MAKE THEIR WAY INTO THE
AREA THIS EVENING WITH THE THICKEST CLOUDS BEING ACROSS THE
NORTHERN THIRD OF THE CWA. STILL COULD GET SOME CLOUDS ACROSS THE
I-72 CORRIDOR, BUT SHOULD REMAIN PARTLY CLOUDY OVERNIGHT.
REMAINDER OF THE FORECAST LOOKS FINE WITH LOWS IN THE MID 40S TO
LOWER 50S. WINDS SHOULD STAY UP A TAD AS WELL WITH GUSTS STILL
SHOWING UP AT SOME SITES. WILL MAKE SOME ADJUSTMENTS TO CLOUD
COVER AND WINDS IN THE GRIDS. WILL SEND AN UPDATE SHORTLY, THOUGH
THERE WILL PROBABLY NOT BE MUCH CHANGE IN THE WORDED FORECAST.
&&
.SHORT TERM...(TONIGHT)
ISSUED AT 255 PM CDT MON MAY 11 2015
A COLD FRONT DELINEATED BY A THIN LINE OF SHOWERS EXTENDED FROM JUST
WEST OF CHICAGO TO JUST EAST OF BLOOMINGTON AND TAYLORVILLE. THIS
FRONT WILL PUSH EAST TO THE IL/IN BORDER BY 00Z/7 PM WITH ISOLATED
SHOWERS POSSIBLE ALONG AND AHEAD OF IT THE REST OF THE EASTERN IN
EASTERN IL. ISOLATED THUNDERSTORMS SHOULD MOSTLY STAY EAST OF
CENTRAL IL OVER INDIANA REST OF TODAY WHILE SEVERE STORMS STAY OVER
OHIO AND EASTERN PARTS OF IN/KY INTO EARLY EVENING. OTHERWISE DRY
CONDITIONS EXPECTED TONIGHT INTO TUE ACROSS CENTRAL AND SOUTHEAST IL
ALONG WITH BREEZY AND COOLER CONDITIONS. LOW CLOUDS WERE DECREASING
BEHIND THE COLD FRONT WEST OF I-55 AT MID AFTERNOON AND EXPECT THESE
CLOUDS TO CONTINUE TO DECREASE OVER EASTERN IL LATE THIS AFTERNOON
AND EARLY EVENING. ANOTHER AREA OF LOW CLOUDS OVER IA AND NW MO WAS
TRACKING EASTWARD AND WILL SKIRT ACROSS THE IL RIVER VALLEY BY THIS
EVENING SO HAVE MORE CLOUDS OVER NORTHERN/NW COUNTIES TONIGHT. THE
SOUTHERN/SE EDGE OF THESE CLOUDS IS DIURNALLY ENHANCED SO MAY SEE
THIS DISSIPATE AFTER SUNSET. 1003 MB SURFACE LOW PRESSURE OVER
CENTRAL MN WILL TRACK EASTWARD ACROSS NORTHERN MI OVERNIGHT AND
FAIRLY TIGHT PRESSURE GRADIENT TO REMAIN OVER CENTRAL IL INTO TUE.
SW WINDS OF 15 TO 25 MPH AND GUSTS OF 25 TO 30 MPH THIS AFTERNOON TO
SHIFT MORE WESTERLY DURING THE NIGHT AND DIMINISH TO 10-17 MPH AFTER
SUNSET WITH GUSTS 18-25 MPH THIS EVENING.
.LONG TERM...(TUESDAY THROUGH MONDAY)
ISSUED AT 255 PM CDT MON MAY 11 2015
A COUPLE COOLER DAYS, ALTHOUGH NOT AS COOL AS ANTICIPATED A FEW DAYS
AGO, ARE EXPECTED TUESDAY AND WEDNESDAY. A SPRAWLING SURFACE HIGH
WILL BUILD ACROSS THE AREA DURING THE PERIOD, WITH THE UPPER LEVEL
FLOW QUICKLY TRANSITIONING FROM WEAK TROFFING TO A BUILDING RIDGE.
THIS SCENARIO IS ALSO SUPPORTIVE OF DRY WEATHER CONDITIONS.
HOWEVER, CONDITIONS FLIP RATHER QUICKLY BACK TO WARM AND
UNSETTLED AFTER THE MIDDLE OF THE WEEK. A SYSTEM CURRENTLY DIVING
DOWN THE WEST COAST WILL CARVE OUT A NEW WESTERN U.S. TROF, WHICH
WILL HELP DEVELOP A DOWNSTREAM EASTERN U.S. RIDGE. DISTURBANCES
EJECTING OUT OF THIS TROF WILL CAUSE PERIODIC SHOWERS/STORMS
ACROSS CENTRAL AND SOUTHEAST ILLINOIS FOR THE END OF THE WEEK AND
THE WEEKEND, MUCH AS WAS SEEN THIS PAST WEEKEND. TEMPERATURES
SHOULD ALSO TREND WELL ABOVE NORMAL, WITH DAYTIME HIGHS HEADING
BACK TOWARD THE 80S BY THE WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1154 PM CDT MON MAY 11 2015
VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES NEXT 24HRS. WRAP-
AROUND CLOUDS CONTINUE TO MOVE ACROSS THE NORTHERN THIRD OF THE
STATE WITH BROKEN TO OVERCAST CLOUDS OCCURRING AT PIA. THESE
CLOUDS SHOULD REACH BMI SO WILL HAVE BROKEN TO OVERCAST CLOUDS AT
BOTH SITES BUT HAVE A TEMPO GROUP FOR BMI FOR FIRST SEVERAL HOURS
OF TAF FOR SCATTERED CLOUDS. OTHER SITES WILL JUST SEE SCATTERED
CLOUDS OVERNIGHT AND THROUGH MOST OF THE DAY. HRRR MODEL SHOWS THE
POSSIBILITY OF SOME BROKEN CIGS REACHING CMI IN THE MORNING SO
WILL HAVE TEMPO GROUP TO COVER THAT IN THE MORNING. ALL SITES WILL
EITHER REMAIN SCATTERED OR SCATTER OUT DURING THE MORNING HOURS
AND THEN BECOME CLEAR LATE MORNING TO EVENING HOURS. WEST WINDS
WILL CONTINUE AND THEN BECOME NORTHWEST TOMORROW EVENING. GUSTY
WINDS ARE EXPECTED AGAIN TOMORROW.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AUTEN
SHORT TERM...07
LONG TERM...BAK
AVIATION...AUTEN
AREA FORECAST DISCUSSION
NWS CARIBOU ME
614 PM EDT TUE MAY 12 2015
.SYNOPSIS...
LOW PRESSURE WILL CONTINUE ACROSS QUEBEC TONIGHT BRINGING A COLD
FRONT INTO THE AREA. THE COLD FRONT WILL PUSH THROUGH THE REGION
WEDNESDAY MORNING AND OFF THE COAST. HIGH PRESSURE WILL BUILD
TOWARD THE REGION LATER WEDNESDAY NIGHT INTO THURSDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
614 PM UPDATE...A LINE OF SHOWERS MOVING OUT OF CENTRAL MAINE
WILL QUICKLY MOVE TO THE NEW BRUNSWICK BORDER OVER THE NEXT 1 TO 2
HOURS. CALLS TO WEATHER SPOTTERS INDICATE SOME HEAVY
DOWNPOURS...BUT LITTLE WIND. THUS FAR ONLY SOME IN CLOUD LIGHTNING
DETECTED. ONCE THIS LINE MOVES OUT OF THE AREA ATTENTION TURNS TO
SHOWERS AND THUNDERSTORMS IN QUEBEC THAT WILL DRIFT INTO FAR
NORTHERN MAINE OVER THE NEXT FEW HOURS. MAIN ADJUSTMENT WAS TO THE
POPS OVER THE NEXT COUPLE OF HOURS TO ACCOUNT FOR THE LINE OF
SHOWERS MOVING OUT OF CENTRAL MAINE.
PREVIOUS DISCUSSION...
ISOLATED THUNDERSTORMS POSSIBLE W/SOME DECENT WIND GUSTS.
LOW CLOUDS SLOWLY ERODING ACROSS THE EASTERN AREAS THIS AFTERNOON
KEEPING THE LLVLS STABLE WHILE WESTERN AND SW AREAS HAVE BROKEN
OUT W/SUNSHINE AND HENCE TEMPS WARMING. THIS HAS ALLOWED FOR
THINGS TO DESTABILIZE MORE. 18Z SURFACE ANALYSIS HAD THE WARM
FRONT/PRE-FRONTAL BOUNDARY SLOWLY LIFT INTO WESTERN MAINE W/THE
COLD FRONT STILL BACK WESTERN QUEBEC. STEADY RAIN HAS ENDED OR
MOVED E W/A MORE SHOWERY NATURE OF THE PRECIP SETTING UP. LATEST
NAM AND RAP SOUNDINGS SUPPORT DECENT SB/MU CAPE OF 700+ JOULES
W/LIS DOWN TO -2 IN THESE AREAS. GOOD SHEAR IN THE 0-6KM LAYER
AROUND 35 KTS. SPC MESO ANALYSIS SHOWED DECENT MID LEVEL LAPSE
RATES OF 6.5 C/KM HELPING W/INSTABILITY. KEPT ENHANCED WORDING FOR
FOR NOW FOR GUSTY WINDS AND HEAVY RAINFALL POTENTIAL. THINGS WILL
WIND DOWN ACROSS THE W AND SW THIS EVENING AND THEN SHIFT ACROSS
THE NORTHERN AREAS AS THE COLD FRONT APCHS W/LOW PRES PASSING
ACROSS SOUTHERN QUEBEC. 12Z UA SHOWED DECENT MID LEVEL COOLING AND
STRONG JET FROM 700-500MBS OF AROUND 65 KTS. THOSE STRONGER WINDS
COULD GET MIXED DOWN SOME TO THE SFC W/ANY ELEVATED CONVECTION.
LEANED W/ENHANCED WORDING FOR THE GUSTY WINDS IN ANY STORMS
THROUGH MIDNIGHT. HEAVY RAINFALL POTENTIAL IS POSSIBLE AS WELL
W/THE STORMS MOVING PARALLEL TO THE UPPER FLOW.
CONVECTIVE POTENTIAL WINDS DOWN AFTER MIDNIGHT W/JUST SHOWERS AND
THE BULK OF THE ACTION ACROSS THE NORTHERN TIER. COOLING TO TAKE
AFFECT AS NW WIND TAKE OVER THROUGH THE COLUMN. WE ARE TALKING
UPPER 30S BACK ACROSS THE WNW BY EARLY WEDNESDAY MORNING W/40S
ELSEWHERE. THIS COLD AIR CAN BE SEEN ALREADY SHOWING UP IN NW
QUEBEC. WEDNESDAY WILL BE MUCH COOLER W/THE UPPER TROF ACROSS THE
REGION W/UPPER 50S NORTH AND WEST WHILE CENTRAL AND DOWNEAST WILL
SEE AROUND 60F OR SO DUE TO SOME DOWNSLOPING. IT WILL BE BREEZY
W/NW WINDS.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
STRONG HIGH PRESSURE WILL BUILD IN FROM THE WEST AND WEDNESDAY
NIGHT AND CREST OVER THE REGION EARLY FRIDAY KEEPING THE STATE
RELATIVELY DRY. WILL BLEND THE GFS AND ECMWF FOR POPS... QPF AND
SKY CONDITIONS. FOR WINDS HAVE USED THE MOSG25. THE SUPER BLEND
WAS USED TO POPULATE THE TEMPERATURE AND DEW POINT GRIDS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
STRONG HIGH PRESSURE WILL MOVE OFF THE EAST COAST LATE FRIDAY.
WEAK LOW PRESSURE WILL PASS TO THE SOUTH OF THE REGION SATURDAY.
HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTH MONDAY. A COLD
FRONT WILL APPROACH FROM THE WEST MONDAY NIGHT AND CROSS THE
REGION TUESDAY. WILL USE THE SUPER BLEND TO POPULATE ALL GRIDS.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
NEAR TERM: MOSTLY VFR EARLYTHIS EVENING AT THE NORTHERN TERMINALS
WITH CONDITIONS TO DROP BACK TO MVFR AND IFR W/THE APCHG COLD
FRONT TONIGHT. IMPROVEMENT TO MVFR BY MID MORNING AND VFR BY LATE
IN THE DAY. KBGR AND KBHB WILL SEE VFR THROUGH TUESDAY. THERE IS A
RISK OF AN ISOLATED TSTM THROUGH THIS EVENING W/GUSTY WINDS.
SHORT TERM: EXPECT VFR CONDITIONS WEDNESDAY NIGHT THROUGH SUNDAY.
&&
.MARINE...
NEAR TERM: SCA FOR HAZARDOUS SEAS IS IN EFFECT INCLUDING THE
INTRA-COASTAL ZONE. A SWELL BEING GENERATED FROM LEFTOVER TD ANA
IS FORECAST LIFT ACROSS THE WATERS LATER THIS EVENING INTO
WEDNESDAY. DECIDED ON HEIGHTS UP TO A RANGE OF 6-7 FT W/THE
HIGHEST WAVES OVER THE OUTER WATERS. THE INTRA-COASTAL ZONE WILL
MOST LIKELY SEE WAVES OF AROUND 5FT W/A 8-9 SECOND PERIOD. FOG
WILL BE A NUISANCE FOR NAVIGATION THROUGH TONIGHT.
FOR THE WINDS, DECIDED ATTM TO KEEP WIND GUSTS IN THE LOWER 2OS
ON WEDNESDAY W/THE NW FLOW. THE OUTER WATERS COULD SEE GUSTS HIT
25 KT FOR A BRIEF PERIOD.
SHORT TERM: HAVE BLENDED THE NAM12 AND GFS40 FOR SUSTAINED WINDS
WEDNESDAY NIGHT THROUGH FRIDAY THEN TRANSITION TO THE SUPER BLEND
WINDS. FOR WAVES: PRIMARY WAVE SYSTEM WILL BE LONG PERIOD SWELL
FROM REMNANTS OF TROPICAL DEPRESSION ANA. EXPECT 5 FEET/9-10
SECONDS WAVE HEIGHTS WEDNESDAY NIGHT SUBSIDING DURING THE DAY
THURSDAY. WILL CARRY AN SCA EARLY WEDNESDAY EVENING BUT EXPECT
SEAS TO SUBSIDE BELOW SCA LATER AT NIGHT AS THE LONG PERIOD WAVE
SYSTEM SUBSIDES. WILL USE THE NEAR SHORE WAVE MODEL THROUGH FRIDAY
THEN TRANSITION TO THE WAVE WATCH III.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM MIDNIGHT TONIGHT
TO MIDNIGHT EDT WEDNESDAY NIGHT FOR ANZ050>052.
&&
$$
NEAR TERM...CB/HEWITT
SHORT TERM...MIGNONE
LONG TERM...MIGNONE
AVIATION...CB/HEWITT/MIGNONE
MARINE...CB/HEWITT/MIGNONE
AREA FORECAST DISCUSSION
NWS CARIBOU ME
354 PM EDT TUE MAY 12 2015
.SYNOPSIS...
LOW PRESSURE WILL CONTINUE ACROSS QUEBEC TONIGHT BRINGING A COLD
FRONT INTO THE AREA. THE COLD FRONT WILL PUSH THROUGH THE REGION
WEDNESDAY MORNING AND OFF THE COAST. HIGH PRESSURE WILL BUILD
TOWARD THE REGION LATER WEDNESDAY NIGHT INTO THURSDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
ISOLATED THUNDERSTORMS POSSIBLE W/SOME DECENT WIND GUSTS.
LOW CLOUDS SLOWLY ERODING ACROSS THE EASTERN AREAS THIS AFTERNOON
KEEPING THE LLVLS STABLE WHILE WESTERN AND SW AREAS HAVE BROKEN
OUT W/SUNSHINE AND HENCE TEMPS WARMING. THIS HAS ALLOWED FOR
THINGS TO DESTABILIZE MORE. 18Z SURFACE ANALYSIS HAD THE WARM
FRONT/PRE-FRONTAL BOUNDARY SLOWLY LIFT INTO WESTERN MAINE W/THE
COLD FRONT STILL BACK WESTERN QUEBEC. STEADY RAIN HAS ENDED OR
MOVED E W/A MORE SHOWERY NATURE OF THE PRECIP SETTING UP. LATEST
NAM AND RAP SOUNDINGS SUPPORT DECENT SB/MU CAPE OF 700+ JOULES
W/LIS DOWN TO -2 IN THESE AREAS. GOOD SHEAR IN THE 0-6KM LAYER
AROUND 35 KTS. SPC MESO ANALYSIS SHOWED DECENT MID LEVEL LAPSE
RATES OF 6.5 C/KM HELPING W/INSTABILITY. KEPT ENHANCED WORDING FOR
FOR NOW FOR GUSTY WINDS AND HEAVY RAINFALL POTENTIAL. THINGS WILL
WIND DOWN ACROSS THE W AND SW THIS EVENING AND THEN SHIFT ACROSS
THE NORTHERN AREAS AS THE COLD FRONT APCHS W/LOW PRES PASSING
ACROSS SOUTHERN QUEBEC. 12Z UA SHOWED DECENT MID LEVEL COOLING AND
STRONG JET FROM 700-500MBS OF AROUND 65 KTS. THOSE STRONGER WINDS
COULD GET MIXED DOWN SOME TO THE SFC W/ANY ELEVATED CONVECTION.
LEANED W/ENHANCED WORDING FOR THE GUSTY WINDS IN ANY STORMS
THROUGH MIDNIGHT. HEAVY RAINFALL POTENTIAL IS POSSIBLE AS WELL
W/THE STORMS MOVING PARALLEL TO THE UPPER FLOW.
CONVECTIVE POTENTIAL WINDS DOWN AFTER MIDNIGHT W/JUST SHOWERS AND
THE BULK OF THE ACTION ACROSS THE NORTHERN TIER. COOLING TO TAKE
AFFECT AS NW WIND TAKE OVER THROUGH THE COLUMN. WE ARE TALKING
UPPER 30S BACK ACROSS THE WNW BY EARLY WEDNESDAY MORNING W/40S
ELSEWHERE. THIS COLD AIR CAN BE SEEN ALREADY SHOWING UP IN NW
QUEBEC. WEDNESDAY WILL BE MUCH COOLER W/THE UPPER TROF ACROSS THE
REGION W/UPPER 50S NORTH AND WEST WHILE CENTRAL AND DOWNEAST WILL
SEE AROUND 60F OR SO DUE TO SOME DOWNSLOPING. IT WILL BE BREEZY
W/NW WINDS.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
STRONG HIGH PRESSURE WILL BUILD IN FROM THE WEST AND WEDNESDAY
NIGHT AND CREST OVER THE REGION EARLY FRIDAY KEEPING THE STATE
RELATIVELY DRY. WILL BLEND THE GFS AND ECMWF FOR POPS... QPF AND
SKY CONDITIONS. FOR WINDS HAVE USED THE MOSG25. THE SUPER BLEND
WAS USED TO POPULATE THE TEMPERATURE AND DEW POINT GRIDS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
STRONG HIGH PRESSURE WILL MOVE OFF THE EAST COAST LATE FRIDAY.
WEAK LOW PRESSURE WILL PASS TO THE SOUTH OF THE REGION SATURDAY.
HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTH MONDAY. A COLD
FRONT WILL APPROACH FROM THE WEST MONDAY NIGHT AND CROSS THE
REGION TUESDAY. WILL USE THE SUPER BLEND TO POPULATE ALL GRIDS.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
NEAR TERM: IFR NORTHERN TERMINALS TO GO VFR THIS EVENING AND THEN
DROP BACK TO MVFR AND IFR W/THE APCHG COLD FRONT TONIGHT.
IMPROVEMENT TO MVFR BY MID MORNING AND VFR BY LATE IN THE DAY. KBGR
AND KBHB WILL SEE VFR THROUGH TUESDAY. THERE IS A RISK OF AN
ISOLATED TSTM THROUGH THIS EVENING W/GUSTY WINDS.
SHORT TERM: EXPECT VFR CONDITIONS WEDNESDAY NIGHT THROUGH SUNDAY.
&&
.MARINE...
NEAR TERM: SCA FOR HAZARDOUS SEAS IS IN EFFECT INCLUDING THE
INTRA-COASTAL ZONE. A SWELL BEING GENERATED FROM LEFTOVER TD ANA
IS FORECAST LIFT ACROSS THE WATERS LATER THIS EVENING INTO
WEDNESDAY. DECIDED ON HEIGHTS UP TO A RANGE OF 6-7 FT W/THE
HIGHEST WAVES OVER THE OUTER WATERS. THE INTRA-COASTAL ZONE WILL
MOST LIKELY SEE WAVES OF AROUND 5FT W/A 8-9 SECOND PERIOD. FOG
WILL BE A NUISANCE FOR NAVIGATION THROUGH TONIGHT.
FOR THE WINDS, DECIDED ATTM TO KEEP WIND GUSTS IN THE LOWER 2OS
ON WEDNESDAY W/THE NW FLOW. THE OUTER WATERS COULD SEE GUSTS HIT
25 KT FOR A BRIEF PERIOD.
SHORT TERM: HAVE BLENDED THE NAM12 AND GFS40 FOR SUSTAINED WINDS
WEDNESDAY NIGHT THROUGH FRIDAY THEN TRANSITION TO THE SUPER BLEND
WINDS. FOR WAVES: PRIMARY WAVE SYSTEM WILL BE LONG PERIOD SWELL
FROM REMNANTS OF TROPICAL DEPRESSION ANA. EXPECT 5 FEET/9-10
SECONDS WAVE HEIGHTS WEDNESDAY NIGHT SUBSIDING DURING THE DAY
THURSDAY. WILL CARRY AN SCA EARLY WEDNESDAY EVENING BUT EXPECT
SEAS TO SUBSIDE BELOW SCA LATER AT NIGHT AS THE LONG PERIOD WAVE
SYSTEM SUBSIDES. WILL USE THE NEAR SHORE WAVE MODEL THROUGH FRIDAY
THEN TRANSITION TO THE WAVE WATCH III.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FROM MIDNIGHT TONIGHT
TO MIDNIGHT EDT WEDNESDAY NIGHT FOR ANZ050>052.
&&
$$
NEAR TERM...HEWITT
SHORT TERM...MIGNONE
LONG TERM...MIGNONE
AVIATION...HEWITT/MIGNONE
MARINE...HEWITT/MIGNONE
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
400 AM EDT TUE MAY 12 2015
.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA LATE TODAY. HIGH PRESSURE
RETURNS WEDNESDAY AND THURSDAY...THEN PUSHES OFFSHORE ON FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE REMNANTS OF ANA HAVE PUSHED WELL OFF THE MID-ATLANTIC COAST
THIS MORNING. THE NEXT FEATURE TO IMPACT THE LOCAL AREA IS A COLD
FRONT CURRENTLY MAKING ITS WAY THROUGH THE OH VALLEY...AND
STRETCHING SOUTHWARD TO THE LOWER MS VALLEY. WARM/HUMID SW FLOW IN
PLACE THIS MORNING IS MAKING IT FEEL MORE LIKE MID-SUMMER WITH
TEMPS GENERALLY IN THE MID 60S TO MID 70S AT THIS HOUR. THE
CURRENT RADAR SCANS SHOWS THAT THE CONVECTION FROM LAST EVENING
HAS WANED. HOWEVER...A NEW ROUND OF SHWR ACTIVITY STRETCHING FROM
NEAR LYNCHBURG TO MARTINSVILLE IS POISED TO MAKE A RUN AT OUR
EASTERN PIEDMONT COUNTIES BY AROUND DAYBREAK. WILL CARRY SLIGHT
CHC POPS WESTERN AREAS THRU AROUND 9 AM TO ACCOUNT FOR THIS
POSSIBILITY. LATEST HRRR APPEARS A BIT ROBUST WITH PCPN MAKING IT
ALL THE WAY TO RICHMOND...BUT DOES SUPPORT THE AFOREMENTIONED
SLIGHT CHC POPS.
THE COLD FRONT CONTINUES TO MOVE EAST THROUGH THE DAY...REACHING
EASTERN PORTIONS OF THE FA AROUND 00Z. AHEAD OF THE FRONT...MODELS
ARE IN GOOD AGREEMENT SHOWING A PRE-FRONTAL TROUGH SHARPENING
ACROSS THE PIEDMONT BY 18Z WITH DEEP LAYERED WSW FLOW BRINGING
DRIER AIR (AND SIGNIFICANT LOWERING OF DEW POINTS) INTO THE
REGION. THE BEST MOISTURE AHEAD OF THE APPROACHING COLD FRONT IS
SHOWN TO QUICKLY SHIFT EAST INTO EASTERN AREAS THIS AFTN/EVE...
ESPECIALLY SE VA AND NE NC. MODEL SOUNDINGS SHOW A STRONG CAP DEVELOPING
BETWEEN 6-8KFT DURING THE AFTN HOURS ALONG AND NW OF A LINE FROM
AVC-PTB-WAL...WHICH WILL INHIBIT CONVECTION. SLOWER DEEP LAYERED
DRYING AND A WEAKER CAP IN SE VA/NE NC DURING THE AFTN/EARLY EVE
MAY RESULT IN POSSIBLE ISOLD/SCT CONVECTION AT TIME OF PEAK
HEATING. POPS WERE ADJUSTED ACCORDINGLY TO REFLECT A 30% POP FROM
ABOUT THE TRI-CITIES ON SOUTHEAST THIS AFTN/EVE. SPC HAS SE VA/NE
NC ONLY IN A MARGINAL RISK OF SVR WX LATER TODAY...AS THERE MAY BE
JUST ENOUGH INSTABILITY/MOISTURE IN PLACE (ML CAPE 1000-1500 J/KG)
COUPLED WITH MODEST SHEAR 20-30 KT TO PRODUCE AN ISOLD DAMAGING
WIND GUST THREAT. OTW...TODAY WILL BE SUMMER-LIKE WITH HIGH TEMPS
IN THE MID-UPR 80S ALONG THE IMMEDIATE COAST...UPR 80S-LOW 90S
ELSEWHERE.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
SUBSTANTIAL DRYING TONIGHT THROUGH WED AS FLOW ALOFT BECOMES NW
AND SFC HIGH PRESSURE BUILDS TWD THE FA FROM THE GREAT LAKES. LOW
TEMPS TONIGHT FROM THE MID-UPR 50S...EXCEPT LOW 60S SE. SUNNY AND
LESS HUMID WED AS SFC HIGH PRESSURE CONTINUES TO BUILD INTO THE
REGION FROM THE NW. HIGH TEMPS RANGING FROM THE MID 60S-LOW 70S
ALONG THE COAST...MID-UPR 70S INLAND. DRY/PLEASANT WX WED NIGHT/THU
W/ LGT/VRB WINDS AND CLEAR-PTCLDY SKY. LOW TEMPS WED NIGHT FROM
THE MID-UPR 40S INLAND TO THE MID 50S AT THE COAST. HIGH TEMPS THU
65 TO 70F AT THE BEACHES TO THE LOW-MID 70S INLAND.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
HIGH PRESSURE RESIDES OVER THE AREA FOR ONE MORE NIGHT...KEEPING
LOW TEMPERATURES IN THE LOWER 50S INLAND AND MID-UPPER 50S AT THE
IMMEDIATE COAST. HIGH PRESSURE THEN SLIDES OFF THE COAST DURING
THE DAY ON FRIDAY...ALLOWING WARM AIR ADVECTION PROCESSES TO
COMMENCE IN RETURN SWLY FLOW. GULF MOISTURE WILL GRADUALLY BE
PULLED INTO THE REGION AROUND THE BACK SIDE OF A LARGE-SCALE HIGH
PRESSURE OVER THE SOUTHEAST COAST...THUS INTRODUCING PRECIPITATION
BACK INTO THE FORECAST BEGINNING FRIDAY AFTERNOON. UNSETTLE
CONDITIONS THEN PREVAIL THROUGH THE UPCOMING WEEKEND AND INTO
EARLY NEXT WEEK WITH NO SIGNIFICANT UPSTREAM FEATURES TO PUSH THE
HIGH SOUTH OR EAST. EXPECT PERIODS OF OFF AND ON RAIN SHOWERS/AFTN
THUNDERSTORMS (30-40 PERCENT) DURING THIS TIMEFRAME. HIGHS SLOWLY
REBOUND TO SLIGHTLY ABOVE SEASONAL NORMALS THROUGH THE WEEKEND AS
THE SFC HIGH MOVES OFFSHORE. EXPECT HIGHS 75-85 (5-7 DEGREES
COOLER AT THE IMMEDIATE COAST) AND LOWS IN THE LOW-MID 60S.
&&
.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
THE REMNANT LOW FROM ANA IS NOW IN VICINITY OF THE CENTRAL NJ
COAST AS OF 06Z...AND IS IN THE PROCESS OF BECOMING ABSORBED BY
LOW PRESSURE OVER THE GREAT LAKES. A COLD FRONT ASSOCIATED WITH
THE GREAT LAKES LOW IS BACK OVER THE OHIO VALLEY. THE LOCAL AREA
IS NOW WITHIN A REGION OF SW FLOW AHEAD OF THE COLD FRONT. BKN
CIGS AOA 6KFT COMBINED WITH A 6-10KT SW WIND SHOULD INHIBIT FOG
DEVELOPMENT OVERNIGHT. THE BEST CHC FOR MVFR VSBY IS AT SBY WHERE
THE DEWPOINT DEPRESSION IS 2F...MEANWHILE OTHER LOCATIONS ARE
8-10F. ISOLATED -SHRA/TSRA WILL LINGER OVERNIGHT...BUT THE
PROBABILITY OF A DIRECTLY AFFECTING A TAF SITE IS VERY LOW.
OTHERWISE...EXPECT BREEZY CONDITIONS TO DEVELOP LATER THIS
MORNING AHEAD OF THE COLD FRONT WITH A SW WIND AVERAGING
12-15KT...WITH GUSTS OF 20-25KT THROUGH THE AFTERNOON. A FEW
-SHRA/TSRA ARE POSSIBLE THIS AFTERNOON MAINLY OVER SE VA/NE NC.
THE COLD FRONT SWEEPS THROUGH THE AREA THIS EVENING...WITH HIGH
PRESSURE PREVAILING MIDWEEK. HIGH PRESSURE MOVES OFFSHORE FRIDAY
AND SATURDAY.
&&
.MARINE...
THE REMNANT LOW OF ANA ABSORBS INTO LOW PRESSURE TRACKING ACROSS THE
SAINT LAWRENCE VALLEY TODAY. THIS WILL DRAG A COLD FRONT TOWARD THE
REGION TODAY...WITH THE BOUNDARY CROSSING THE COAST THIS EVENING.
EXPECT A SW WIND TO AVERAGE ~15KT OVER THE BAY EARLY TODAY WITH 15-
20KT OVER THE OCEAN...BEFORE RELAXING TO 10-15KT THIS AFTERNOON. A
SHORT DURATION PERIOD OF ~20KT IS POSSIBLE ACROSS THE LOWER
BAY/LOWER JAMES AROUND 10-12Z BUT SHOULD NOT BE LONG ENOUGH TO
WARRANT AN SCA. ADDITIONALLY...A FEW TSTMS ARE POSSIBLE WITH THE
FRONTAL PASSAGE THIS AFTERNOON AND EVENING. MODEST CAA ARRIVES LATER
TONIGHT INTO EARLY WEDNESDAY...ESPECIALLY ACROSS THE NRN HALF OF THE
AREA IN THE WAKE OF THE FRONT. AN SCA HAS BEEN ISSUED FOR THE BAY
FOR LATE TONIGHT INTO WEDNESDAY MORNING. THE SCA N OF PARRAMORE
ISLAND HAS BEEN EXTENDED THROUGH TODAY AS SEAS COULD LINGER ~5FT
(ESPECIALLY OUT NEAR 20NM)...AND CONTINUING TONIGHT INTO WEDNESDAY
MORNING FOR THE CAA SURGE. A SECONDARY NORTHERLY SURGE WEDNESDAY
NIGHT HAS THE POTENTIAL TO PRODUCE MARGINAL SCA CONDITIONS...BEFORE
HIGH PRESSURE SETTLES INTO THE REGION THURSDAY AND THURSDAY NIGHT.
HIGH PRESSURE MOVES OFFSHORE FRIDAY AND SATURDAY ALLOWING THE WIND
TO RETURN TO SSW. SEAS SHOULD AVERAGE 2-4FT LATER WEDNESDAY THROUGH
SATURDAY...WITH WAVES IN THE BAY AVERAGING 1-3FT.
&&
.CLIMATE...
RATHER HOT TUE...WITH A GOOD CHANCE AT SEEING OUR 1ST 90-
DEGREE DAY OF THE YEAR:
MEAN DATE OF 1ST 90-DEGREE DAY (1981-2010 CLIMATOLOGY):
RICHMOND....MAY 13TH
NORFOLK.....MAY 17TH
SALISBURY...MAY 27TH
ELIZ CITY...MAY 25TH
RECORD HIGHS POSSIBLE TUE...RECORDS ARE LISTED BELOW FOR MAY 12TH:
RICHMOND....92 (1956)
NORFOLK.....92 (1881)
SALISBURY...93 (1914)
ELIZ CITY...90 (2001)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR ANZ650-
652-654.
&&
$$
SYNOPSIS...JDM
NEAR TERM...JDM
SHORT TERM...ALB/JDM
LONG TERM...BMD
AVIATION...AJZ
MARINE...AJZ
CLIMATE...AKQ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
139 AM EDT TUE MAY 12 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 421 PM EDT MON MAY 11 2015
WATER VAPOR IMAGERY AND RAP ANALYSIS SHOW THE MID LEVEL LOW THAT WAS
OVER WRN NEBRASKA/SD 24HRS AGO NOW CENTERED IN WCNTRL MN. AHEAD OF
FEATURE...WARM CONVEYOR BELT MOISTURE RIBBON EXTENDS FROM THE LWR
MISSISSIPPI VALLEY TO THE WRN GREAT LAKES. RESULT HAS BEEN NMRS SHRA
SPREADING ACROSS THE FCST AREA TODAY. A FEW TSTMS WERE NOTED THIS
MORNING OVER THE W HALF OF UPPER MI. AT THE SFC...LOW PRES LOCATED
IN CNTRL MN IS BECOMING LESS WELL-DEFINED WITH TENDENCY FOR LOW PRES
REDEVELOPMENT AT THE TRIPLE POINT FARTHER E. OCCLUDED FRONT IS
APPROACHING THE MI/WI BORDER AS OF 20Z.
AS THE WARM CONVEYOR MOISTURE RIBBON TRANSLATES E...WIDESPREAD SHRA
NOW OVER THE E HALF OF THE FCST AREA WILL ALSO SHIFT E AND OUT OF
THE AREA IN THE NEXT FEW HRS. FOG AND SOME -DZ WILL PERSIST IN THE
UPSLOPE FLOW OFF LAKE SUPERIOR INTO THE KEWEENAW AND WRN PORTIONS OF
NCNTRL UPPER MI...AND A FEW SHRA MAY DEVELOP NEAR THE OCCLUDED FRONT
WHICH SHOULD LIFT INTO OR THRU MUCH OF CNTRL AND ERN UPPER MI THIS
EVENING. OTHERWISE...AS MID LEVEL LOW OPENS UP AND UPPER TROF MOVES
E INTO THE WRN GREAT LAKES TONIGHT...DEEPER MOISTURE WILL WRAP BACK
INTO THE AREA FROM THE N AND W. AIDED BY DEEP CYCLONIC FLOW...SHRA
WILL SPREAD BACK INTO THE FCST AREA...ESPECIALLY ACROSS THE W. AS
CAA INCREASES OVERNIGHT...FCST SOUNDINGS/WETBULB ZERO HEIGHTS
SUGGEST POTENTIAL FOR SNOW TO MIX WITH THE RAIN OVER THE HIGH
TERRAIN OF THE W LATE TONIGHT.
AS TROF CONTINUES TO SHIFT E TUE...DEEP LAYER QVECTOR DIVERGENCE
OVERSPREADS THE AREA WITH HEIGHTS BEGINNING TO RISE...MORE
SUBSTANTIALLY IN THE AFTN. THIS WILL TEND TO DIMINISH THE WRAP
AROUND PCPN WITH TIME...BUT THIS WILL BE COUNTERACTED BY SHARP
CYCLONIC FLOW AND CONSIDERABLE LOW TO MID LEVEL MOISTURE THAT
LINGERS THRU THE DAY. THIS WILL RESULT IN PCPN BEING MOST PERSISTENT
IN THE AREAS THAT SEE UPSLOPING UNDER NW TO N WINDS. DOWNSLOPE AREAS
WILL SEE PCPN DIMINISH OR END. CONTINUED CAA WILL DROP 850MB TEMPS
TO -3 TO AS LOW AS -6C...AND THIS WILL RESULT IN RAIN MIXING WITH
SNOW...MAINLY OVER THE HIGHER TERRAIN OF THE W AND CNTRL. PCPN WILL
LIKELY CHANGE TO ALL SNOW AT LEAST FOR A TIME OVER THE HIGH TERRAIN
OF THE W HALF AS LOWEST 850MB TEMPS ARE FCST THERE. THAT AREA WILL
ALSO HAVE THE BEST CHANCE FOR A LITTLE SNOW ACCUMULATION ON GRASSY
SFCS. IT WILL BE AN UNSEASONABLY COLD DAY WITH TEMPS AROUND 20
DEGREES BLO NORMAL ACROSS THE W AND N WHERE TEMPS WILL STRUGGLE TO
GET MUCH ABOVE 40F. ACROSS THE SCNTRL...TEMPS MAY SNEAK INTO THE LWR
50S. BLUSTERY WINDS WILL ADD TO THE CHILL.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 255 PM EDT MON MAY 11 2015
WILL STILL HAVE SOME LINGERING MAINLY SNOW SHOWERS /WITH A FEW RAIN
SHOWERS OR AREAS OF DRIZZLE MIXED IN/ TUESDAY NIGHT OVER THE N HALF
OF UPPER MI. THE BEST CHANCE OF PRECIP WILL BE N CENTRAL AS
FAVORABLE N-NNW WINDS RESIDE THERE FROM THE SFC-850MB. TEMPERATURES
WILL BE COOLING INTO THE LOW 30S OVERNIGHT...WITH LOCATIONS OVER THE
INTERIOR W HALF FALLING INTO THE MID 20S AS WINDS BECOME NEARLY CALM
AND DRIER AIR WORKS IN AND 850MB TEMPS BEGIN TO WARM SLIGHTLY FROM -
4 TO -6C...TO AROUND -3C.
HIGH PRESSURE WILL BE STRETCHING FROM HUDSON BAY THROUGH MANITOBA
AND MN...DOWN THROUGH THE MS VALLEY AT 00Z WEDNESDAY. LOOK FOR THE
AREA OF HIGH PRESSURE TO BUILD ACROSS THE UPPER GREAT LAKES THROUGH
WEDNESDAY...WITH DRY WEATHER FIGURED INTO AT LEAST WEDNESDAY
EVENING. WAA WILL TAKE HOLD AT THE SFC ON MAINLY S WINDS OVER THE W
HALF OF THE CWA...WITH AFTERNOON HIGHS IN THE 50S FOR MOST LOCATIONS
/EXCLUDING THE COOLER N CENTRAL AND E
LAKE SUPERIOR SHORELINE/ AS 850MB TEMPS REBOUND TO AROUND 4C W TO 1C
E.
PRECIP COULD SLIDE IN AS EARLY AS LATE WEDNESDAY AFTERNOON SW /GFS
SOLUTION/. THIS WOULD BE ALONG THE SW AS AN INITIAL FRONTAL BOUNDARY
SHIFTS TO OUR N. THE MAIN CONCERN IS THAT THE LOWER LEVELS WILL BE
TOO DRY WITH THE SFC RIDGE STILL OVER MUCH OF THE AREA WITH THIS
BOUNDARY/SHORTWAVE ROUNDING THE 500MB RIDGE. WILL CONTINUE TO GO
WITH A MINIMAL PRECIP SOLUTION FOR THIS PERIOD. THE SFC HIGH WILL
SHIFT ACROSS THE ENTIRE GREAT LAKES REGION WEDNESDAY NIGHT...WITH
SLOWLY INCREASING S FLOW OVER UPPER MI PUSHING IN INCREASED MOISTURE
AS 850MB TEMPS RUMP TO AROUND 8C OVER THE SW.
THE APEX OF THE 500MB RIDGE WILL BE ACROSS THE AREA THURSDAY
AFTERNOON...WITH FCST MODELS INDICATING A NEARING EMBEDDED 500MB
TROUGH IN THE SW FLOW OVER THE N PLAINS AND W MN. THE GFS HAS A
DEEPER/WRAPPED UP SFC LOW OVER THE CENTRAL PLAINS OFF THE GFS IS NOT
QUITE A S STRONG AS THE ECMWF...ESPECIALLY THE PREVIOUS 11/06Z RUN.
THIS LEADS TO ONLY MODERATE CONFIDENCE IN THE FCST BEYOND THURSDAY.
THE DIFFERENCE SHOWS UP WELL IN THE MODEL QPF...WITH THE 11/06Z GFS
SHOWING 24HR PRECIP OF 0.75-1.45IN BY 00Z SATURDAY. THE 11/00Z ECMWF
ON THE OTHER HAND RANGES FROM LESS THAN 0.10IN ACROSS THE KEWEENAW
PENINSULA...TO 0.5IN OVER FAR S MENOMINEE CO. THIS WILL BE AS THE
SFC LOW OFF THE GFS TRACKS FROM THE CENTRAL PLAINS TO N LAKE MI BY
00Z SATURDAY. THE CANADIAN THE ECMWF KEEP A RIDGE ACROSS LAKE
SUPERIOR AND MUCH OF UPPER MI DURING THE SAME TIME PERIOD. ON A
POSITIVE NOTE...THE 11/12Z GFS CAME IN AT LEAST A LITTLE LESS
INTENSE WITH THE SFC LOW...AND DROPS ABOUT 1/2 AS MUCH PRECIP.
AN ADDITIONAL LOW DEVELOPING OFF THE N ROCKIES TOWARDS THE END OF
THE WORK WEEK WILL LIKELY BE SET UP ACROSS MT AND WY SATURDAY
MORNING...AND MOVE ACROSS THE DAKOTAS SATURDAY NIGHT...AND THE UPPER
GREAT LAKES ON MONDAY. THE 12Z RUNS HAVE BECOME MUCH MORE IN LINE
WITH THE SFC LOW TRACKING OVER E MN/FAR W LAKE SUPERIOR BY 06Z
MONDAY. THE RESULT IS AT LEAST MODERATE CONFIDENCE IN RAIN. WILL GO
WITH LIKELY PRECIP FOR SUNDAY NIGHT ACROSS MOST OF THE CWA. SO FOR
THE UPCOMING WEEKEND IT LOOKS TO BE MAINLY DRY SATURDAY...WITH WET
WEATHER APPROACHING SUNDAY AND POSSIBLY LINGERING INTO MONDAY AS THE
SFC LOW SLOWLY EDGES E OF THE CWA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 138 AM EDT TUE MAY 12 2015
A LOW PRES SYSTEM WILL MOVE E ACROSS THE UPPER GREAT LAKES TONIGHT
AND THEN E TO QUEBEC TUE. ABUNDANT LOW-LEVEL MOISTURE WILL GENERALLY
SUPPORT IFR TO LIFR CONDITIONS OVERNIGHT TONIGHT AND -SHRA AT
KIWD/KCMX/KSAW TONIGHT WITH THE LOWEST CONDITIONS OCCURRING AT
TERMINALS EXPERIENCING UPSLOPE WINDS. COLDER AIR WRAPPING INTO THE
AREA BEHIND THE LOW SHOULD BE COLD ENOUGH TO RESULT IN -SHRA MIXING
WITH OR CHANGING OVER TO -SHSN LATE TONIGHT/TUE MORNING. CHANGE OVER
TO ALL SNOW IS MORE LIKELY TO OCCUR AT KIWD/KCMX. DRIER AIR WORKING
IN BEHIND THE LOW LATE TUE AFTERNOON INTO TUE EVENING WILL END PCPN
AND ALLOW ALL THE TAF SITES TO IMPROVE TO MVFR BY TUE EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 421 PM EDT MON MAY 11 2015
ONGOING MARGINAL GALES OVER THE WRN PORTION OF LAKE SUPERIOR WILL
CONTINUE TO DIMINISH...FALLING BLO GALE FORCE EARLY THIS EVENING...
AS PRES GRADIENT WEAKENS AND WINDS BACK DUE TO LOW PRES SHIFTING
ACROSS UPPER MI AND ERN LAKE SUPERIOR. ON THE BACK SIDE OF THE
LOW...NNW WINDS WILL INCREASE TO 20-30KT ACROSS CNTRL AND ERN LAKE
SUPERIOR LATE TONIGHT/TUE MORNING. MAY SEE A FEW GALE FORCE GUSTS
TUE MORNING OVER SCNTRL LAKE SUPERIOR AROUND GRANITE ISLAND DUE TO
LOCAL COASTAL CONVERGENCE. WINDS WILL DIMINISH FROM W TO E TUE
AFTN/TUE NIGHT WITH LIGHT WINDS MOSTLY UNDER 15KT TO FOLLOW FOR
WED/THU AS HIGH PRES BUILDS INTO THE UPPER LAKES WED AND THEN
LINGERS INTO THU. AS THE HIGH PRES SHIFTS E AND A WEAK LOW PRES
PASSES BY TO THE S...WINDS MAY INCREASE SOME FOR THU NIGHT/FRI
BEFORE DIMINISHING AGAIN ON SAT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...ROLFSON
LONG TERM...KF
AVIATION...VOSS
MARINE...ROLFSON
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1210 AM EDT TUE MAY 12 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 328 PM EDT MON MAY 11 2015
A COLD FRONT WILL COME THROUGH THE AREA TONIGHT ENDING OVER A
WEEKS WORTH OF UNSEASONABLY WARM TEMPERATURES. THERE WILL BE
SHOWERS AND A FEW THUNDERSTORMS AHEAD OF THE COLD FRONT THIS
EVENING...THEN A FEW LIGHT RAIN SHOWERS TUESDAY AS CHILLY WESTERLY
WINDS KEEP AFTERNOON TEMPERATURES IN THE 50S. SKIES WILL BECOME
PARTLY CLOUDY TUESDAY NIGHT REMAIN SO ON WEDNESDAY. ANOTHER STORM
SYSTEM WILL BRING MORE SHOWERS AND POSSIBLY THUNDERSTORMS LATER
THIS WEEK INTO THE WEEKEND. IT WILL WARM UP AGAIN BY THE END TOO.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 328 PM EDT MON MAY 11 2015
THE MAIN ISSUE IS THE THREAT FOR SEVERE STORMS (NOT MUCH) THEN THE
CHANCE FOR LIGHT RAIN SHOWERS TUESDAY AND POSSIBLE FROST TOMORROW
NIGHT.
THE LATEST RAP MODEL SHOWS THE LOW LEVEL JET CORE LIFTING
NORTHEAST FROM SOUTHWEST LOWER MICHIGAN EARLY THIS AFTERNOON TO
THE THUMB AREA BY EARLY THIS EVENING. THE MOST UNSTABLE CAPE
(OVER 500 J/KG) STAYS JUST EAST OF OUR CWA LATE THIS AFTERNOON.
WHILE THERE IS GOOD DEEP LAYER SHEAR...THE RAIN COOLED AIR OVER
MOST OF OUR CWA WILL MITIGATE MOST OF THE SEVERE WEATHER THREAT.
POSSIBLY ISOLATED DAMAGING WINDS COULD HAPPEN OVER OUR EXTREME
SOUTHEAST COUNTIES EARLY THIS EVENING.
OTHERWISE THE AREA OF RAIN WILL MOVE OUT BY MID EVENING. THEN THE
DRY SLOT MOVES IN BEHIND THE COLD FRONT SO SKIES WILL CLEAR AT
LEAST PARTLY. WE THEN GET WRAP AROUND COLD AIR ADVECTION
INSTABILITY SHOWERS (MOSTLY SPRINKLES) TUESDAY AND IT WILL BE
BREEZY AND CHILLY WITH HIGHS ONLY IN THE 50S.
THE UPPER TROUGH MOVES OUT QUICKLY TUESDAY NIGHT ALLOWING FOR SOME
CLEARING. FROST IS POSSIBLE OVER NORTHERN AREAS WEDNESDAY MORNING.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 328 PM EDT MON MAY 11 2015
AS HIGH PRESSURE MOVES EAST THURSDAY LOW PRESSURE WILL MOVE TOWARD
THE GREAT LAKES. CONFIDENCE IS INCREASING THAT WE/LL SEE SOME
PRECIPITATION MOVE OVER THE CWA THURSDAY NIGHT AND FRIDAY. ADDED
THUNDER TO THE GRIDS FRIDAY AS LI/S FALL TO AROUND -2C AND CAPE
INCREASES TO 1K J/KG. MUCH OF THE PCPN WILL BE EAST OF THE CWA BY
SATURDAY AS THE SFC LOW MOVES AWAY. HOWEVER WE/LL KEEP LOW POPS IN
TO COVER THE UPPER TROUGH.
CHANCES FOR TSRA WILL INCREASE TOWARD THE BEGINNING OF NEXT WEEK AS
A STRONGER COLD FRONT MOVES TOWARD THE CWA. STRONG SOUTH FLOW AHEAD
OF IT WILL SEND ABUNDANT MOISTURE NORTHWARD AND CREATE SOME
INSTABILITY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1209 AM EDT TUE MAY 12 2015
PREDOMINATELY VFR OVERNIGHT BUT AROUND 12Z TUESDAY MVFR CIGS WILL
SPREAD IN FROM THE WEST AND PERSIST MUCH OF THE DAY. A FEW LIGHT
SHOWERS OR SPRINKLES ARE POSSIBLE BUT IF ANY REDUCTIONS TO VSBYS
OCCURRED IT SHOULD BE VERY BRIEF. CIGS ARE EXPECTED TO IMPROVE TO
VFR AGAIN TUESDAY NIGHT AFTER 00-02Z.
GUSTY SOUTHWEST TO WEST SFC WINDS OF 15 TO 25 KNOTS TONIGHT WILL
INCREASE TO 20 TO 30 KNOTS ON TUESDAY... RESULTING IN SOME LOW
LEVEL TURBULENCE. WINDS WILL DECREASE TUESDAY NIGHT AFTER 00-02Z.
&&
.MARINE...
ISSUED AT 328 PM EDT MON MAY 11 2015
THE STRONG WINDS BEHIND OUR SYSTEM WILL LEAD TO 4 TO 6 FOOT WAVES
AND WINDS TO 30 KNOTS BY MID MORNING TUESDAY. AS A RESULT I ISSUED
A SMALL CRAFT ADVISORY.
&&
.HYDROLOGY...
ISSUED AT 1222 PM EDT MON MAY 11 2015
ADDITIONAL RAINFALL AMOUNTS BETWEEN A QUARTER AND THREE QUARTERS OF
AN INCH WILL BE POSSIBLE MAINLY BEFORE MIDNIGHT TONIGHT. WE ARE
ISSUING ADVISORIES FOR THE SYCAMORE CREEK AT HOLT...WHICH SHOULD
CREST SHORTLY AFTER MIDNIGHT TONIGHT. CONFIDENCE IS HIGH THAT IT
WILL REMAIN BELOW FLOOD STAGE.
AFTER TONIGHT DRY CONDITIONS SHOULD PREVAIL UNTIL THURSDAY...WHEN
RAIN SHOWERS RETURN TO THE AREA. THIS SHOULD GIVE RIVER LEVELS
SOME TIME TO SUBSIDE.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY FROM 5 AM EARLY THIS MORNING TO 6 PM EDT
THIS EVENING FOR LMZ844>849.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...93
AVIATION...MEADE
HYDROLOGY...TJT
MARINE...WDM
AREA FORECAST DISCUSSION...UPDATED
NWS DULUTH MN
1237 AM CDT TUE MAY 12 2015
.UPDATE...
ISSUED AT 734 PM CDT MON MAY 11 2015
UPDATED POPS AS CURRENT RADAR TRENDS SHOW PRECIPITATION INCREASING
IN COVERAGE AND INTENSITY ACROSS THE FORECAST AREA. AN AREA OF
CONVECTIVE SHOWERS WITH REFLECTIVITY VALUES OVER 40 DBZ HAS
DEVELOPED ABOUT 30 MILES NORTH OF DULUTH...ON THE LEADING EDGE OF
THE H50 LOW/VORT MAX AND AN REGION OF LOW LEVEL FRONTOGENESIS
DEPICTED IN THE LATEST RUC MESO ANALYSIS. ANTICIPATE ECHOES TO
CONTINUE TO INTENSIFY OVER THE IRON RANGE/ARROWHEAD AS THE VORT
MAX TRANSLATES EAST ACROSS THE FORECAST AREA. AT THIS TIME THE
PRECIP TYPE BEING REPORTED BY AUTOMATED STATIONS IS ALL RAIN.
HOWEVER...AS PROFILES COOL THROUGH THE EVENING THE RAIN IS
EXPECTED TO CHANGE OVER TO SNOW FOR AT LEAST THE NORTHERN PORTION
OF MN.
ALSO ADDED AREAS OF FOG ALONG SOUTH SHORE OF LAKE SUPERIOR WHERE
SURFACE OBSERVATIONS AND SPOTTERS HAVE REPORTED VISIBILITY OF LESS
THAN A HALF MILE AT TIMES.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 328 PM CDT MON MAY 11 2015
A CLOSED AND NEARLY STACKED UPPER LOW OVER MINNESOTA WILL CONTINUE
SHOWERS OVER THE REGION TONIGHT AS IT SLOWLY MOVES EAST. THE
STRONGEST LIFT NORTH OF THE BAROCLINIC ZONE WILL BE IN NORTHERN
MINNESOTA BUT CANNOT RULE OUT SHOWERS ACROSS REST OF THE FORECAST
AREA. COLD AIR ADVECTION BEHIND THE LOW LATER TONIGHT COULD RESULT
IN SNOW SHOWERS. BUT WITH THE WET GROUND, DO NOT EXPECT MUCH
ACCUMULATION. THERE WILL BE A GRADUAL END TO ANY SHOWERS SLOWLY FORM
WEST TO EAST TUESDAY WITH SFC HIGH PRESSURE BUILDING OVER THE
AREA.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 328 PM CDT MON MAY 11 2015
THE NORTHLAND CAN EXPECT A BIT OF WET PATTERN OVER THE NEXT WEEK
WITH SEVERAL OPPORTUNITIES FOR RAIN.
HIGH PRESSURE WILL BE OVER THE NORTHLAND TUESDAY NIGHT AND WILL MAKE
FOR A COOL AND RELATIVELY CLEAR NIGHT. TEMPERATURES WILL DIP INTO
THE LOWER 30S AND UPPER 20S. THERE WILL BE INCREASING CLOUD COVER
FROM THE WEST LATE TUESDAY NIGHT AND WEDNESDAY AS A MID LEVEL
FRONTOGENETICAL BAND MOVES INTO THE NORTHLAND. THIS FRONTOGENETICAL
BAND WILL LIKELY RESULT IN RAINS SHOWERS FOR PARTS OF THE NORTHLAND
WEDNESDAY AND WEDNESDAY NIGHT. THE SW FORECAST AREA HAS THE BEST
CHANCE OF RAIN.
A LOW PRESSURE SYSTEM IN THE CENTRAL PLAINS WEDNESDAY NIGHT WILL
LIFT INTO THE NORTHERN PLAINS THURSDAY AND THURSDAY NIGHT. THE
MODELS ARE IN FAIRLY GOOD AGREEMENT THAT THIS WILL BRING MORE RAIN
TO THE NORTHLAND THURSDAY INTO FRIDAY. THE SOUTHERN FORECAST AREA
HAS THE BEST CHANCE OF RAIN WITH THE PASSAGE OF THIS SYSTEM.
WEAK HIGH PRESSURE WILL GIVE ANOTHER SHORT BREAK BETWEEN WEATHER
SYSTEMS LATE FRIDAY AND SATURDAY. A LOW IN THE NORTHERN PLAINS WILL
LIFT A WARM FRONT INTO THE UPPER MIDWEST. THE GFS AND ECMWF ARE IN
RELATIVELY GOOD AGREEMENT THAT THE NORTHLAND WILL SEE SHOWERS AND
STORMS LATE SATURDAY INTO EARLY MONDAY WITH THE PASSAGE OF THIS
SYSTEM. THE SOUTHERN FORECAST AREA HAS THE BEST CHANCE OF SEEING
THUNDER SINCE THE WARM FRONT MIGHT GET SHUNTED SOUTH BECAUSE OF COOL
EASTERLY FLOW FROM LAKE SUPERIOR AND ONTARIO. HOWEVER...THERE COULD
BE ELEVATED CONVECTION NORTH OF THE WARM FRONT...BUT THOUGHT IT TOO
EARLY TO INCLUDE THUNDER OVER ALL OF THE NORTHLAND.
TEMPERATURES WILL REMAIN COOL FOR THE MIDDLE OF THE WEEK...BUT WILL
LIKELY REBOUND TO CLOSE TO NORMAL BY THIS WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1235 AM CDT TUE MAY 12 2015
WIDESPREAD RAIN/DRIZZLE...MIXING WITH SNOW AT TIMES...AND LIFR/IFR
CONDITIONS WILL PREVAIL OVERNIGHT. CEILINGS WILL GRADUALLY IMPROVE
FROM THE WEST THROUGH THE DAY AS DRIER AIR ASSOCIATED WITH
BUILDING HIGH PRESSURE FILTERS INTO THE REGION. HOWEVER...THE COLD
AIR MASS AND LINGERING MOISTURE WILL BE SUFFICIENT FOR INSTABILITY
SHOWERS INTO THE AFTERNOON. A FEW OF THE SHOWERS WILL BE CAPABLE
OF PRODUCING GUSTY NORTH WINDS TO 30 KT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 34 50 38 54 / 10 60 40 50
INL 30 56 40 58 / 10 0 50 50
BRD 37 52 46 59 / 10 60 50 60
HYR 31 56 43 61 / 10 40 30 50
ASX 32 52 39 57 / 10 40 40 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
LS...NONE.
&&
$$
UPDATE...GRANING
SHORT TERM...CLC
LONG TERM...GROCHOCINSKI
AVIATION...CLC
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
843 PM MDT WED MAY 13 2015
.UPDATE...
MID- AND HIGH-LEVEL CLOUD COVER EARLIER TODAY DELAYED AND REDUCED
DESTABILIZATION...AND LARGE-SCALE FORCING WAS WEAK. THE RESULT IS
WHAT WE SEE ON RADAR AT MID-EVENING...ONE BATCH OF STORMS CENTERED
ACROSS WHEATLAND COUNTY AND REMNANTS OF CONVECTION WHICH FORMED ON
THE BIGHORN MOUNTAINS FROM SHERIDAN TO LAME DEER. THERE/S NOT MUCH
ELSE GOING ON...AND NEITHER RADAR TRENDS OR RECENT HRRR RUNS WOULD
SUGGEST MUCH OTHER DEVELOPMENT OVERNIGHT. THUS...WE CHOSE TO LOWER
POPS INTO THE SLIGHT CHANCE CATEGORY IN MANY AREAS LIKE BILLINGS
WHILE MAINTAINING A BIT HIGHER POPS DOWNSTREAM OF CURRENT ACTIVITY.
THE RISK OF STRONG STORMS IS WANING AND WILL DIMINISH BY ABOUT 10
PM MDT AS SURFACE-BASED INSTABILITY DECREASES. SCHULTZ
&&
.SHORT TERM...VALID FOR THU AND FRI...
A SHORTWAVE SEEN ON WATER VAPOR IMAGERY OVER NM THIS AFTERNOON WAS
PUMPING MOISTURE NORTHWARD INTO THE FORECAST AREA IN THE FORM OF
MID AND HIGH CLOUDS. THE CLOUDINESS SLOWED TEMPERATURE RISES...BUT
RECENTLY THERE HAVE BEEN MORE SUNNY BREAKS AND READINGS HAVE
CLIMBED INTO THE 60S. FURTHER S OVER WY...THERE WERE SCATTERED
SHOWERS AND THUNDERSTORMS MOVING N. 19Z MESOANALYSIS DID NOT SHOW
ANY APPRECIABLE SURFACE CAPE OVER THE FORECAST AREA. THE LATEST
SREF DID SHOW A HIGH PROBABILITY OF 500 J/KG SURFACE CAPES BY 21Z
OVER WESTERN AND SOUTH CENTRAL AREAS. THERE WAS A LOWER
PROBABILITY OF 1000 J/KG OVER THESE AREAS AS WELL. THE SHEAR
LOOKED MARGINAL FOR SEVERE WEATHER THIS AFTERNOON. SOME JET
DIVERGENCE WILL MOVE THROUGH THE REGION THROUGH THIS EVENING AND
WILL COMBINE WITH THE MOISTURE AND EASTERLY UPSLOPE FLOW TO BRING
SCATTERED SHOWERS AND THUNDERSTORMS TO THE AREA. PER THE
ABOVE...THERE COULD BE AN ISOLATED STRONG/SEVERE STORM. THE
AIRMASS WILL BECOME MORE STABLE AFTER 06Z...BUT STEEP MID/UPPER
LEVEL LAPSE RATES WILL SUPPORT A SLIGHT CHANCE OF THUNDER.
MORE JET DIVERGENCE WILL CROSS THE AREA THU AND THU NIGHT. THERE
WILL ALSO BE A DIFFLUENT FLOW ALOFT AND LOW-LEVEL UPSLOPE FLOW...
WITH INCREASING SHORTWAVES MOVING THROUGH THE FLOW. MOISTURE WILL
CONTINUE TO INCREASE OVER THE AREA AS WELL. CAPES WILL BE SIMILAR
TO TODAY/S EXPECTED VALUES AND THE SHEAR WILL BE SLIGHTLY HIGHER
THAN TODAY/S SHEAR. MODELS HAD SOME LOW CHANCES OF PRECIPITATION
OVER THE AREA THROUGH 18Z...THEN DEVELOPED PRECIPITATION ALONG THE
TERRAIN THROUGH THE EVENING. THE QPF WILL SPREAD NE OVERNIGHT.
ADJUSTED THE MORNING POPS A BIT...OTHERWISE KEPT THE POPS
BASICALLY THE SAME AS THE PREVIOUS FORECAST THROUGH THU NIGHT.
AGAIN...AN ISOLATED STRONG OR SEVERE STORM IS POSSIBLE IN THE
AFTERNOON AND EVENING. TEMPERATURES ON THU WILL BE A LITTLE LOWER
THAN TODAY/S HIGHS.
MORE JET DIVERGENCE WILL CROSS THE AREA FRI AND FRI NIGHT AS THE
BROAD W COAST UPPER LOW SHIFTS E. SHORTWAVE ENERGY WILL CONTINUE
INCREASING OVER THE AREA AND AN 850 MB JET WILL INCREASE
PRECIPITABLE WATERS TO AROUND 1 INCH OVER THE E HALF OF THE AREA.
CAPES AND SHEAR WILL BE LOWER THAN RECENT DAYS. HAD MAINLY LIKELY
POPS THROUGH THE PERIOD...EXCEPT LOWERED THEM ACROSS THE S LATE
FRI NIGHT AS THE GFS TRIES TO BRING A DRY SLOT N INTO THE AREA.
ALSO THERE WERE STILL SOME SUBTLE MODEL DIFFERENCES IN QPF
AMOUNTS/PLACEMENT DURING FRI AND FRI NIGHT...SO DID NOT WANT TO GO
CATEGORICAL AT THIS POINT. HAD JUST A SLIGHT MENTION OF THUNDER IN
THE AFTERNOON AND EVENING. INHIBITED MIXING WILL LEAD TO HIGH
TEMPERATURES IN THE 50S ON FRI. ARTHUR
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
CONFIDENCE REMAINS HIGH FOR A WET WEEKEND AND WELL BELOW NORMAL
TEMPERATURES BUT THERE STILL REMAINS SOME UNCERTAINTY AS TO THE
OVERALL EXTENT OF COVERAGE AND PRECIP AMOUNTS. MODELS KEEP A LARGE
TROUGH ACROSS THE ENTIRE WESTERN U.S. SATURDAY INTO SUNDAY WITH
SEVERAL UPPER LOWS OVER THE GREAT BASIN AND FOUR CORNERS REGION.
THESE LOWS WILL SHIFT NORTHEAST SATURDAY BUT MODELS DIFFER IN
THEIR PLACEMENT. THE GFS BRINGS THE LOW ACROSS OUR AREA INTO
NORTHEAST MONTANA SHIFTING MOST IF NOT ALL THE PRECIP WITH IT
SATURDAY LEAVING A MOSTLY DRY DAY. HOWEVER...THE ECMWF TAKES THE
LOW INTO FAR SOUTHEAST MONTANA/NORTHEAST WYOMING RESULTING IN THE
AREA OF PRECIP TO BE ACROSS MOST OF OUR FORECAST AREA. WILL
CONTINUE TO TAKE A BLEND OF THE MODELS AS PRECIP AMOUNTS COULD
STILL BE IN THE 1-3 INCH RANGE OVER A 3 DAY PERIOD FRIDAY THROUGH
SUNDAY. GIVEN PLACEMENT OF THE LOW AND PRECIP AREAS...MODELS ALSO
ARE OUT OF AGREEMENT WITH HIGH TEMPERATURES FOR
SATURDAY...BASICALLY A 20 DEGREE DIFFERENCE FROM 48 WITH THE ECMWF
TO 68 WITH THE MEX GUIDANCE.
MODELS CONTINUE TO KICK THE LOWS EAST SUNDAY WHICH WOULD START A
DRYING TREND FROM WEST TO EAST. PRESSURE GRADIENTS WILL BE TIGHT
ACROSS THE CENTRAL AND ESPECIALLY EASTERN AREAS WHICH WILL RESULT
IN VERY GUSTY NORTHERLY WINDS. THIS COMBINED WITH COOL
TEMPERATURES SUNDAY WILL RESULT IN A BLUSTERY "COLD" DAY. 700MB
TEMPERATURES WILL AGAIN SUPPORT SOME SNOW FOR THE MOUNTAINS BUT
AMOUNTS ARE UNCERTAIN AT THIS TIME.
MODELS THEN BRING ANOTHER UPPER LOW AND TROUGH ACROSS THE
FORECAST AREA EARLY NEXT WEEK BRINGING CONTINUED PRECIP CHANCES.
TEMPERATURES WILL BE BELOW NORMAL THROUGH THE ENTIRE EXTENDED
PERIOD ESPECIALLY ON SUNDAY. HOOLEY
&&
.AVIATION...
AN AREA OF THUNDERSTORMS AROUND HARLOWTON WILL SLOWLY MOVE EAST
AND WILL DISSIPATE BY AROUND MIDNIGHT. NO ACTIVITY EXPECTED TO
IMPACT ANY TERMINALS. VFR CONDITIONS EXPECTED ACROSS THE AREA.
SCATTERED THUNDERSTORMS WILL AGAIN BE POSSIBLE TOMORROW AFTERNOON.
REIMER
&&
.PRELIMINARY POINT TEMP/POPS...
THU FRI SAT SUN MON TUE WED
-----------------------------------------------------------
BIL 046/064 048/056 045/053 041/052 038/060 041/056 042/058
24/T 66/T 66/T 66/W 22/W 24/W 44/W
LVM 040/063 044/056 040/052 038/054 034/058 037/055 038/060
25/T 56/T 67/T 66/W 23/W 33/W 44/W
HDN 045/068 047/060 045/056 041/053 036/063 041/059 041/060
22/T 66/T 57/T 76/W 22/W 23/W 44/W
MLS 045/067 046/058 046/058 042/054 035/060 040/058 041/059
31/B 35/T 78/T 76/W 22/W 23/W 44/W
4BQ 047/067 047/058 046/061 042/052 034/059 039/057 040/057
31/B 47/T 77/T 76/W 32/W 33/W 66/W
BHK 043/063 042/058 045/062 041/051 032/056 037/057 038/056
42/W 15/T 78/T 87/W 32/W 23/W 55/W
SHR 041/066 044/061 041/055 038/051 035/058 040/055 039/057
43/T 66/T 57/T 76/W 32/W 35/W 66/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1130 PM MDT MON MAY 11 2015
AVIATION SECTION UPDATED
.DISCUSSION... UPDATE FORTHCOMING. SOUTHWEST FLOW ALOFT CONTINUES TO
BRING MOISTURE AND INSTABILITY TO SOUTHWEST MONTANA WHERE SCATTERED
SHOWERS SHOULD CONTINUE THROUGH THE NIGHT. BOTH THE HRRR AND RUC
ANALYSIS BRING SHOWERS AS FAR NORTH AS JUST ABOUT GREAT FALLS BY
12Z. TEMPERATURES OVERNIGHT LOOK ON TRACK.
&&
.AVIATION... UPDATED 0530Z. VFR CONDITIONS EXPECTED TONIGHT.
SOUTHWEST FLOW ALOFT AHEAD OF A LOW PRESSURE SYSTEM ALONG THE OREGON
COAST WILL PUSH EXTENSIVE MOISTURE INTO CENTRAL/SOUTHWEST MT
TONIGHT. THIS WILL RESULT IN WIDESPREAD MID-LEVEL CEILINGS
(GENERALLY IN THE 6000-10000 FT RANGE) AT ALL TAF SITES WITH
ISOLATED -SHRA VCNTY KHLN/KBZN DEVELOPING AROUND 09-12Z. SCATTERED
SHOWERS AND ISOLATED -TSRA BECOME MORE LIKELY FROM KHLN SOUTH TO THE
MT/ID BORDER BY MID-AFTN AS THE COASTAL LOW COMES INLAND AND BRINGS
ADDITIONAL MOISTURE AND INSTABILITY. BRIEF MVFR CEILINGS AND
MODERATE RAINFALL POSSIBLE NEAR KHLN/KBZN WITH ANY STRONGER
CONVECTIVE CELLS.
WARANAUSKAS
&&
.PREV DISCUSSION...ISSUED 259 PM MDT MON MAY 11 2015
MONDAY THROUGH WEDNESDAY...CONDITIONS WILL GENERALLY CHANGE TO A
WETTER PATTERN THROUGH THE MIDDLE OF THE WEEK AS SHORTWAVE TROUGHS
MOVE ONSHORE AND BEGIN TO BRING MOISTURE INTO THE REGION. SOME
SHOWERS OVER THE HIGHER TERRAIN WILL BE POSSIBLE THIS EVENING AS
THE FIRST SHORTWAVE MOVES INTO THE AREA. PRECIPITATION WILL BE
LIMITED WITH THIS SYSTEM WITH MOST OF THE SHOWERS OCCURRING OVER
THE ROCKY MOUNTAIN FRONT. THE NEXT SYSTEM WILL BEGIN TO MOVE INTO
MONTANA TUESDAY NIGHT AND SHOULD BRING AN INCREASE IN SHOWERS AND
THUNDERSTORMS TO THE AREA TUESDAY AFTERNOON AND EVENING. THIS
EVENT LOOKS LIKE IT SHOULD BRING MORE WIDESPREAD PRECIPITATION TO
THE AREA AS THE MOVES ACROSS THE STATE WEDNESDAY. PRECIPITATION IS
EXPECTED TO DECREASE WEDNESDAY AFTERNOON AND EVENING. TEMPERATURES
SHOULD COOL OFF TUESDAY AND WEDNESDAY BACK BELOW SEASONAL
AVERAGES. SUK
WEDNESDAY NIGHT THROUGH MONDAY. AT THIS TIME, FORECAST CONFIDENCE
IS LOW FOR MUCH OF THIS PERIOD AS PRIMARY FORECAST MODELS NOT
SHOWING MUCH CONSENSUS, ESPECIALLY ON PRECIPITATION COVERAGE AND
AMOUNTS. THE MODEL DIFFERENCES CENTER ON THE EVOLUTION OF A BROAD
SHORTWAVE TROF THAT WILL BE OFF THE CALIFORNIA COAST ON THURSDAY.
MODELS ARE IN GENERALLY GOOD AGREEMENT THAT THE TROF WILL MAKE
SLOW EASTWARD PROGRESS AND BE CENTERED OVER THE GREAT BASIN/DESERT
SOUTHWEST BY LATE FRIDAY. PLUMES OF MOISTURE STREAMING NORTHWARD
AHEAD OF THE TROF AXIS WILL BRING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS INTO MT BY THURS AFTN CONTINUING THRU FRIDAY, WITH
THE ECMWF MODEL INDICATING MUCH WIDER PRECIP COVERAGE OVER
CENTRAL/SOUTHWEST MT. THINGS GET MORE COMPLICATED OVER THE WEEKEND
AS THE TROF LIFTS NORTHEASTWARD TOWARD THE CENTRAL ROCKIES. BOTH
THE GFS AND EC MODELS SHIFT OUR WINDS ALOFT TO EASTERLY AS THE
TROF PASSES TO OUR SOUTH, SETTING UP THE POSSIBILITY OF PULLING
EXTENSIVE GULF OF MEXICO MOISTURE THROUGH THE UPPER MIDWEST AND
INTO THE TREASURE STATE ON BOTH SAT/SUN. THE EC IS NOTABLY
STRONGER WITH THIS LONG MOISTURE FETCH, DRIVEN MAINLY BY A CLOSED
MID-LEVEL LOW PRESSURE AREA WITHIN THE TROF, WHEREAS THE GFS
INDICATES AN OVERALL WEAKER TROF WITH LESS MOISTURE OVER OUR
REGION. IN FACT, THE GFS HAS MUCH OF THE TROF AND PRECIPITATION
OUT OF OUR AREA BY SUNDAY MORNING WHILE THE EC PAINTS EXTENSIVE
RAINFALL WITH AMOUNTS RANGING FROM 0.1 INCH ALONG THE HI-LINE TO
0.5-0.75 INCH FROM GREAT FALLS SOUTHWARD TO THE IDAHO BORDER.
GIVEN THE TROUBLESOME MODEL DIFFERENCES, THE CURRENT EXTENDED
FORECAST LARGELY RELIES ON CLIMATOLOGICAL PRECIP PROBABILITIES
(MOSTLY 30-40%) FOR SATURDAY AND EARLY SUNDAY, THEN REDUCES RAINFALL
CHANCES SUN EVE INTO MONDAY AS THE TROF HEADS TOWARD THE GREAT LAKES
STATES. THE GOOD NEWS IS THAT IT LOOKS THAT MOST/ALL OF THE FORECAST
AREA SHOULD RECEIVE SOME NEEDED RAINFALL THIS WEEKEND; WE`LL JUST
HAVE TO WAIT FOR ADDITIONAL MODEL OUTPUT TO GET A BETTER ESTIMATE ON
AMOUNTS. AS FOR TEMPERATURES, THEY WILL REMAIN AT OR SLIGHTLY ABOVE
SEASONAL VALUES THROUGH THE LATTER HALF OF THE WEEK, WITH HIGHS IN
THE MID- AND UPPER 60S EACH DAY. WARANAUSKAS
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 36 60 41 59 / 10 20 30 60
CTB 30 56 35 51 / 10 10 20 70
HLN 40 61 41 65 / 30 30 40 50
BZN 38 60 38 66 / 20 20 50 40
WEY 30 62 31 61 / 30 40 40 30
DLN 41 62 41 67 / 20 40 50 40
HVR 33 63 36 59 / 10 10 20 60
LWT 37 59 39 63 / 20 20 30 50
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
WEATHER.GOV/GREATFALLS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
606 PM CDT WED MAY 13 2015
.SHORT TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 305 PM CDT WED MAY 13 2015
TONIGHT
LATEST SHORT TERM PROGS IN AGREEMENT SHOWING THAT GOING RAINFALL
FCST FOR TONIGHT IS ON TRACK WITH PCPN ACTIVITY DEVELOPING OVER KS
THEN EXPANDING NWD INTO THE CWA EARLY THIS EVENING. GIVEN
COMBINATION OF UPPER SUPPORT VIA POTENT VORT MAX/STRONG DIVG
WORKING IN TANDEM WITH RATHER MOIST 305K UPGLIDE...SEEMS
REASONABLE TO ASSUME THAT SEVERAL LOCATIONS SHOULD SEE RAINFALL
TOTALS OF AT LEAST HALF AN INCH MAINLY OVER THE SRN CWA WHERE
LIFT/MOISTURE WILL BE MORE PREVALENT. IN ADDITION...MODELS ARE
SHOWING INSTABILITY PARAMETERS WILL BE WEAK AT BEST SO ANY TSTM
DEVELOPMENT SHOULD BE ISOLATED.
DEE
THURSDAY THROUGH SATURDAY
TIMING AND POTENTIAL FOR SEVERE STORMS BOTH FRIDAY AND SATURDAY
WILL BE THE MAIN FORECAST CONCERNS.
OUR AREA WILL GENERALLY BE IN SOUTH OR SOUTHWEST MID TROPOSPHERIC
FLOW THE NEXT FEW DAYS. WATER VAPOR IMAGERY EARLY THIS WEDNESDAY
AFTERNOON...IN COMBINATION WITH EARLY AFTERNOON RAP MODEL
INTITIALIZATIONS...SHOWED FAIRLY IMPRESSIVE SHORTWAVE TROUGH FROM
COLORADO DOWN INTO WEST TEXAS. THIS WILL LIFT NORTHEAST ACROSS THE
AREA TONIGHT AND THURSDAY. BRIEF SHORTWAVE RIDGING BUILDS IN FOR
LATE THURSDAY/EARLY THURSDAY NIGHT...WHILE A STRONG CLOSED LOW
DIGS DOWN INTO NEVADA AND CALIFORNIA. GENERAL MODEL CONSENSUS
SHOWS THE CENTER OF THAT 500 MB LOW SHOULD LIFT OUT INTO NORTHEAST
WYOMING OR SOUTHEAST MONTANA BY SATURDAY EVENING.
THURSDAY...SHOWERS WILL LINGER AT LEAST IN THE MORNING...WITH
ISOLATED THUNDER POSSIBLE. CHANCES DECREASE THROUGH THE AFTERNOON.
EXPECT AT LEAST THE SOUTHWEST HALF OF OUR FORECAST AREA TO SEE
SOME AFTERNOON SUNSHINE AND THAT SHOULD HELP PUSH HIGHS INTO THE
70S THERE. AREAS FROM AROUND YANKTON DOWN TO ONAWA...HARLAN AND
RED OAK MAY ONLY TOP OUT FROM 65 TO 70. PCPN AMOUNTS THURSDAY ARE
EXPECTED TO BE MOSTLY UNDER 0.25 INCHES.
A WEAK COLD FRONT WILL SETTLE DOWN INTO THE FORECAST AREA THURSDAY
NIGHT AND THEN STALL. SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG
AND NORTH OF THE BOUNDARY THURSDAY NIGHT AS THE LOW LEVEL JET
INCREASES AND CAUSES ISENTROPIC LIFT. BEST FOCUS SEEMS TO BE OVER
SOUTHEAST NEBRASKA.
FRIDAY AND FRIDAY NIGHT WILL BE INTERESTING. SOUTHERLY LOW LEVEL
FLOW INCREASES AS LOW PRESSURE INITIALLY OVER NORTHEAST COLORADO AT
12Z FRIDAY LIFTS NORTH TO WEST/NORTHWEST OF VALENTINE BY 06Z
SATURDAY. HIGHS FRIDAY SHOULD REACH 75 TO 80...PUSHING BOUNDARY
LAYER CAPE VALUES INTO THE 1500 TO 3000 J/KG RANGE. 0-6 KM AGL BULK
SHEAR VALUES SHOULD BE MOSTLY 25-40 KNOTS. STORMS MAY INITIALLY BE
MOSTLY NORTH OF THE FRONT...BUT THEN COULD ALSO DEVELOP IN THE WARM
SECTOR OR FARTHER BACK TO THE WEST IN CENTRAL NEBRASKA LATER IN THE
DAY. DETAILS SHOULD BECOME MORE CLEAR WITH THURSDAY MODEL RUNS ON
THE LOCATION OF FRONTAL BOUNDARIES WHICH WILL HELP FOCUS THE
ACTIVITY IN THE AFTERNOON AND EVENING. STORM COVERAGE MAY DROP OFF
DRASTICALLY AFTER MIDNIGHT.
SATURDAY...OVERALL PARAMETERS ARE EXPECTED TO BE IN PLACE FOR
ANOTHER POSSIBLE SEVERE EVENT...BUT NOT COMPLETELY SOLD ON THAT
SINCE IT WILL AT LEAST SOMEWHAT DEPEND ON WHAT HAPPENS FRIDAY. MID
LEVEL WINDS SHOULD INCREASE AND THEREFORE BULK SHEAR VALUES MAY
END UP HIGHER THAN THOSE FRIDAY. TIMING OF CONVECTION WILL BE THE
KEY.
MILLER
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 305 PM CDT WED MAY 13 2015
STORMS SHOULD LINGER INTO SATURDAY NIGHT...WITH SHOWERS/A FEW
EMBEDDED STORMS POSSIBLE SUNDAY MORNING. THE 12Z GFS WAS MOSTLY
DRY IN OUR AREA SUNDAY...BUT THE 12Z ECMWF WAS ABOUT 6 HOURS
SLOWER LIFTING PCPN OUT OF THE AREA. SO...FOR NOW WE HAVE KEPT
SOME LOW POPS SUNDAY IN OUR NORTHERN ZONES SUNDAY.
SUNDAY NIGHT THROUGH TUESDAY SHOULD BE LESS ACTIVE AS HIGH PRESSURE
BUILDS INTO THE REGION WITH COOL TEMPERATURES. SOME LOWS COULD DROP
DOWN TO NEAR 40. IT APPEARS THAT CHANCES FOR SHOWERS/STORMS WILL
INCREASE AGAIN BY TUESDAY NIGHT AND WEDNESDAY AS SHORTWAVE ENERGY
MOVES IN FROM THE WEST/SOUTHWEST.
MILLER
&&
.AVIATION...(00Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 605 PM CDT WED MAY 13 2015
RAIN IS BEGINNING TO OVERSPREAD THE AREA AND WILL LAST INTO
THURSDAY MORNING. VFR CIGS WILL DETERIORATE TO MVFR/IFR ALONG
WITH SOME MVFR VSBYS. CIGS WILL BEGIN TO IMPROVE FROM WEST TO EAST
21-00Z. BRISK SOUTHEAST WINDS 8 TO 18KTS THROUGH THURSDAY MORNING
WILL DECREASE TO 10KTS OR LESS THURSDAY AFTERNOON. WILL MENTION
LLWS AT KOMA AND KLNK 02Z-12Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DEE/MILLER
LONG TERM...MILLER
AVIATION...ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1238 PM CDT TUE MAY 12 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT TUE MAY 12 2015
HIGH PRESSURE CENTERED ACROSS KS MOVES EAST INTO MISSOURI TODAY.
LOW PRESSURE WILL BEGIN TO ORGANIZE ACROSS THE NRN HIGH PLAINS
THIS AFTERNOON. THE MODEL CONSENSUS SHOWS STRONG RETURN FLOW
DEVELOPING THIS AFTERNOON WITH SOUTH WINDS INCREASING TO 20 TO 30
MPH ACROSS WRN NEB. THESE WINDS SHOULD CONTINUE TONIGHT AS THE LOW
LEVEL JET FORMS AND STRENGTHENS TO AROUND 50 KT.
THE TEMPERATURE FORECAST TODAY FOLLOWS THE WARMER SIDE OF THE MODEL
CONSENSUS. SEVERAL MODELS WERE VERY COLD WITH HIGHS IN THE 60S WHILE
THE RAP WAS VERY WARM WITH HIGHS IN THE UPPER 70S. THE FORECAST IS
FOR HIGHS IN THE UPPER 60S TO MID 70S.
LOWS TONIGHT FALL INTO THE UPPER 40S TO AROUND 50. SOUTH WINDS AT 15
TO 20 MPH SHOULD KEEPS LOWS MILD.
LASTLY...THE MODELS SHOW A WEAK DISTURBANCE FIRING THUNDERSTORMS ON
THE LARAMIE AND FRONT RANGES LATE THIS AFTERNOON AROUND 21Z WHICH
CARRY EAST TOWARD WESTERN NEBRASKA. THE BEST GUESS IS FOR ISOLATED
SPRINKLES THIS EVENING. THE GFS WAS THE WET MODEL WHICH ACTUALLY
SHOWS SOME MEASURABLE QPF.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 359 AM CDT TUE MAY 12 2015
MODELS CONTINUE TO ADVERTISE A RAPID RETURN OF GULF MOISTURE TAKING
PLACE WEDNESDAY...WITH MODELS PROJECTING 850 MB DEW POINTS IN THE
10 TO 12C RANGE BY WEDNESDAY EVENING ACROSS THE REGION.
A LARGE UPPER TROUGH WILL BE TAKING SHAPE ALONG THE WEST COAST MID
TO LATE WEEK...WITH A LEAD SHORTWAVE EJECTING NORTHEAST THROUGH THE
PLAINS AHEAD OF THE TROUGH WEDNESDAY NIGHT INTO THURSDAY. THIS
SYSTEM IS SHOWN TO HAVE SOMEWHAT OF A NEGATIVE TILT...WHICH WILL
HELP DRAW MOISTURE WESTWARD INTO THE HIGH PLAINS. THE COMBINATION OF
STRONG LIFT AND MOISTURE TRANSPORT ON A SOUTHERLY LOW LEVEL
JET...CONTINUES TO GIVE CONFIDENCE THAT PRECIPITATION SHOULD RESULT
LATE WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. WILL MAINTAIN THE
LIKELY POPS ALONG AND EAST OF HIGHWAY 83 WEDNESDAY NIGHT...AND ALSO
INTRODUCE EVENING LIKELY POPS ALONG A SURFACE TROUGH ACROSS THE
PANHANDLE INTO THE WESTERN SANDHILLS.
THE LEAD WAVE QUICKLY PASSES AND MOVES NORTHEAST AWAY FROM THE AREA
THURSDAY. ATTENTION THEN TURNS TO THE LONG WAVE TROUGH ALONG THE
WEST COAST. MODELS/ENSEMBLES PROJECT THIS TO MOVE EAST AS A CLOSED
SYSTEM DURING THE WEEKEND. THE GENERAL CONSENSUS IN THE MODELS AND
ENSEMBLE MEAN IS FOR THE CENTER OF THE SYSTEM TO TRACK ACROSS
WYOMING INTO SOUTH DAKOTA. THIS PUTS OUR AREA IN THE WARM MOIST
SECTOR. INSTABILITY LOOKS TO BE STRONG...AND AS DEEP LAYER SHEAR
INCREASES...STRONG TO SEVERE STORMS WILL LIKELY RESULT. WILL
INTRODUCE THE POTENTIAL FOR SEVERE THUNDERSTORMS IN THE HAZARDOUS
WEATHER OUTLOOK FOR FRIDAY AND SATURDAY. THE GFS AND ECMWF CONTINUE
TO DIFFER SOMEWHAT ON THE LOW LEVEL BOUNDARY PLACEMENT...BUT THE
LATEST TREND IS TO HOLD THE DRY LINE BACK TO THE WEST ACROSS WESTERN
NEBRASKA INTO WESTERN KANSAS...WHICH WOULD PLACE SEVERE STORM
DEVELOPMENT ACROSS THE FORECAST AREA OF WESTERN AND NORTH CENTRAL
NEBRASKA. WE WILL LIKELY BE IN THE MIDST OF THE MID LEVEL DRY SLOT
SUNDAY AS THE STORM SYSTEM CROSSES THE DAKOTAS...BUT AT LEAST SOME
CHANCE FOR SHOWERS IN WRAP AROUND PATTERN ACROSS NORTHERN NEBRASKA.
DRY WEATHER FOR MONDAY...THEN MORE CHANCES FOR RAIN NEXT WEEK BEYOND
THE FORECAST PERIOD...AS THE NEXT DEEP TROUGH MOVES EAST INTO THE
WESTERN CONUS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1238 PM CDT TUE MAY 12 2015
FOR THE 18Z KLBF AND KVTN TAF...HIGH PRESSURE WILL BUILD EAST
ACROSS THE MID-MISSISSIPPI VALLEY WITH A BROAD AREA OF LOW
PRESSURE DEVELOPING WEST OF THE ROCKIES. THIS WILL INCREASE THE
PRESSURE GRADIENT ACROSS WEST CENTRAL NEBRASKA...PROVIDING FOR
INCREASING SOUTHERLY WINDS...WHICH WILL CONTINUE THROUGH THE
OVERNIGHT HOURS. LLWS MAY BECOME TROUBLESOME ACROSS OUR EASTERN
ZONES OVERNIGHT...MAINLY IMPACTING KONL...KBBW...AND POSSIBLY
KLBF. OTHERWISE INCREASING CLOUDINESS EARLY ON WEDNESDAY WILL LEAD
TO OVC SKIES BY EARLY AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 359 AM CDT TUE MAY 12 2015
THE COMBINATION OF SEASONAL SNOW MELT IN THE UPPER SOUTH PLATTE
RIVER BASIN AND RECENT HEAVY PRECIPITATION OVER WESTERN NEBRASKA AND
NORTHEAST COLORADO WILL LEAD TO FLOODING ON THE SOUTH PLATTE AND
PLATTE RIVERS IN SOUTHWEST NEBRASKA LATER THIS WEEK AND INTO EARLY
NEXT WEEK. AT THIS TIME SOME UNCERTAINTY STILL REMAINS WITH THE
FORECAST AS KEY UPSTREAM GAUGES IN NORTHEAST COLORADO HAVE YET TO
CREST. HOWEVER...LATEST PROJECTIONS CONTINUE TO HIGHLIGHT AN
INCREASING THREAT FOR SIGNIFICANT FLOODING TO OCCUR...POTENTIALLY
NEAR SEPTEMBER 2013 FLOOD LEVELS.
RIVER STAGE FORECASTS WILL BE CLOSELY MONITORED AND UPDATED ONCE
MORE UPSTREAM RIVER DATA BECOMES AVAILABLE. PERSONS THAT LIVE IN
VULNERABLE AREAS ALONG THE SOUTH PLATTE RIVER AND PLATTE RIVER IN
SOUTHWEST NEBRASKA SHOULD PAY CLOSE ATTENTION TO FLOOD FORECASTS IN
THE COMING DAYS AND BE PREPARED TO TAKE PROPER ACTION.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...TAYLOR
AVIATION...JACOBS
HYDROLOGY...MARTIN/TAYLOR
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
630 AM CDT TUE MAY 12 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT TUE MAY 12 2015
HIGH PRESSURE CENTERED ACROSS KS MOVES EAST INTO
MISSOURI TODAY. LOW PRESSURE WILL BEGIN TO ORGANIZE ACROSS THE NRN
HIGH PLAINS THIS AFTERNOON. THE MODEL CONSENSUS SHOWS STRONG RETURN
FLOW DEVELOPING THIS AFTERNOON WITH SOUTH WINDS INCREASING TO 20 TO
30 MPH ACROSS WRN NEB. THESE WINDS SHOULD CONTINUE TONIGHT AS THE
LOW LEVEL JET FORMS AND STRENGTHENS TO AROUND 50 KT.
THE TEMPERATURE FORECAST TODAY FOLLOWS THE WARMER SIDE OF THE MODEL
CONSENSUS. SEVERAL MODELS WERE VERY COLD WITH HIGHS IN THE 60S WHILE
THE RAP WAS VERY WARM WITH HIGHS IN THE UPPER 70S. THE FORECAST IS
FOR HIGHS IN THE UPPER 60S TO MID 70S.
LOWS TONIGHT FALL INTO THE UPPER 40S TO AROUND 50. SOUTH WINDS AT 15
TO 20 MPH SHOULD KEEPS LOWS MILD.
LASTLY...THE MODELS SHOW A WEAK DISTURBANCE FIRING THUNDERSTORMS ON
THE LARAMIE AND FRONT RANGES LATE THIS AFTERNOON AROUND 21Z WHICH
CARRY EAST TOWARD WESTERN NEBRASKA. THE BEST GUESS IS FOR ISOLATED
SPRINKLES THIS EVENING. THE GFS WAS THE WET MODEL WHICH ACTUALLY
SHOWS SOME MEASURABLE QPF.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 359 AM CDT TUE MAY 12 2015
MODELS CONTINUE TO ADVERTISE A RAPID RETURN OF GULF MOISTURE TAKING
PLACE WEDNESDAY...WITH MODELS PROJECTING 850 MB DEW POINTS IN THE
10 TO 12C RANGE BY WEDNESDAY EVENING ACROSS THE REGION.
A LARGE UPPER TROUGH WILL BE TAKING SHAPE ALONG THE WEST COAST MID
TO LATE WEEK...WITH A LEAD SHORTWAVE EJECTING NORTHEAST THROUGH THE
PLAINS AHEAD OF THE TROUGH WEDNESDAY NIGHT INTO THURSDAY. THIS
SYSTEM IS SHOWN TO HAVE SOMEWHAT OF A NEGATIVE TILT...WHICH WILL
HELP DRAW MOISTURE WESTWARD INTO THE HIGH PLAINS. THE COMBINATION OF
STRONG LIFT AND MOISTURE TRANSPORT ON A SOUTHERLY LOW LEVEL
JET...CONTINUES TO GIVE CONFIDENCE THAT PRECIPITATION SHOULD RESULT
LATE WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. WILL MAINTAIN THE
LIKELY POPS ALONG AND EAST OF HIGHWAY 83 WEDNESDAY NIGHT...AND ALSO
INTRODUCE EVENING LIKELY POPS ALONG A SURFACE TROUGH ACROSS THE
PANHANDLE INTO THE WESTERN SANDHILLS.
THE LEAD WAVE QUICKLY PASSES AND MOVES NORTHEAST AWAY FROM THE AREA
THURSDAY. ATTENTION THEN TURNS TO THE LONG WAVE TROUGH ALONG THE
WEST COAST. MODELS/ENSEMBLES PROJECT THIS TO MOVE EAST AS A CLOSED
SYSTEM DURING THE WEEKEND. THE GENERAL CONSENSUS IN THE MODELS AND
ENSEMBLE MEAN IS FOR THE CENTER OF THE SYSTEM TO TRACK ACROSS
WYOMING INTO SOUTH DAKOTA. THIS PUTS OUR AREA IN THE WARM MOIST
SECTOR. INSTABILITY LOOKS TO BE STRONG...AND AS DEEP LAYER SHEAR
INCREASES...STRONG TO SEVERE STORMS WILL LIKELY RESULT. WILL
INTRODUCE THE POTENTIAL FOR SEVERE THUNDERSTORMS IN THE HAZARDOUS
WEATHER OUTLOOK FOR FRIDAY AND SATURDAY. THE GFS AND ECMWF CONTINUE
TO DIFFER SOMEWHAT ON THE LOW LEVEL BOUNDARY PLACEMENT...BUT THE
LATEST TREND IS TO HOLD THE DRY LINE BACK TO THE WEST ACROSS WESTERN
NEBRASKA INTO WESTERN KANSAS...WHICH WOULD PLACE SEVERE STORM
DEVELOPMENT ACROSS THE FORECAST AREA OF WESTERN AND NORTH CENTRAL
NEBRASKA. WE WILL LIKELY BE IN THE MIDST OF THE MID LEVEL DRY SLOT
SUNDAY AS THE STORM SYSTEM CROSSES THE DAKOTAS...BUT AT LEAST SOME
CHANCE FOR SHOWERS IN WRAP AROUND PATTERN ACROSS NORTHERN NEBRASKA.
DRY WEATHER FOR MONDAY...THEN MORE CHANCES FOR RAIN NEXT WEEK BEYOND
THE FORECAST PERIOD...AS THE NEXT DEEP TROUGH MOVES EAST INTO THE
WESTERN CONUS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 630 AM CDT TUE MAY 12 2015
VFR IS EXPECTED ALL AREAS TODAY AND TONIGHT.
STRONG SOUTH WINDS DEVELOP TODAY INCREASING TO 18020G32KT.
ISOLATED TSTMS ARE EXPECTED ACROSS THE LARAMIE AND COLORADO FRONT
RANGES AOA 21Z THIS AFTN. THERE IS A SLIGHT CHANCE THESE STORMS
COULD REACH WRN NEB THIS EVENING IN THE FORM OF -SHRA/SPRINKLES.
&&
.HYDROLOGY...
ISSUED AT 359 AM CDT TUE MAY 12 2015
THE COMBINATION OF SEASONAL SNOW MELT IN THE UPPER SOUTH PLATTE
RIVER BASIN AND RECENT HEAVY PRECIPITATION OVER WESTERN NEBRASKA AND
NORTHEAST COLORADO WILL LEAD TO FLOODING ON THE SOUTH PLATTE AND
PLATTE RIVERS IN SOUTHWEST NEBRASKA LATER THIS WEEK AND INTO EARLY
NEXT WEEK. AT THIS TIME SOME UNCERTAINTY STILL REMAINS WITH THE
FORECAST AS KEY UPSTREAM GAUGES IN NORTHEAST COLORADO HAVE YET TO
CREST. HOWEVER...LATEST PROJECTIONS CONTINUE TO HIGHLIGHT AN
INCREASING THREAT FOR SIGNIFICANT FLOODING TO OCCUR...POTENTIALLY
NEAR SEPTEMBER 2013 FLOOD LEVELS.
RIVER STAGE FORECASTS WILL BE CLOSELY MONITORED AND UPDATED ONCE
MORE UPSTREAM RIVER DATA BECOMES AVAILABLE. PERSONS THAT LIVE IN
VULNERABLE AREAS ALONG THE SOUTH PLATTE RIVER AND PLATTE RIVER IN
SOUTHWEST NEBRASKA SHOULD PAY CLOSE ATTENTION TO FLOOD FORECASTS IN
THE COMING DAYS AND BE PREPARED TO TAKE PROPER ACTION.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY UNTIL 9 AM CDT /8 AM MDT/ THIS MORNING FOR
NEZ006>010-026>029-038-058-059-069>071.
FREEZE WARNING UNTIL 9 AM CDT /8 AM MDT/ THIS MORNING FOR NEZ004-
005-022>025-035>037-056-057-094.
&&
$$
SHORT TERM...CDC
LONG TERM...TAYLOR
AVIATION...CDC
HYDROLOGY...MARTIN/TAYLOR
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
411 AM CDT TUE MAY 12 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT TUE MAY 12 2015
HIGH PRESSURE CENTERED ACROSS KS MOVES EAST INTO
MISSOURI TODAY. LOW PRESSURE WILL BEGIN TO ORGANIZE ACROSS THE NRN
HIGH PLAINS THIS AFTERNOON. THE MODEL CONSENSUS SHOWS STRONG RETURN
FLOW DEVELOPING THIS AFTERNOON WITH SOUTH WINDS INCREASING TO 20 TO
30 MPH ACROSS WRN NEB. THESE WINDS SHOULD CONTINUE TONIGHT AS THE
LOW LEVEL JET FORMS AND STRENGTHENS TO AROUND 50 KT.
THE TEMPERATURE FORECAST TODAY FOLLOWS THE WARMER SIDE OF THE MODEL
CONSENSUS. SEVERAL MODELS WERE VERY COLD WITH HIGHS IN THE 60S WHILE
THE RAP WAS VERY WARM WITH HIGHS IN THE UPPER 70S. THE FORECAST IS
FOR HIGHS IN THE UPPER 60S TO MID 70S.
LOWS TONIGHT FALL INTO THE UPPER 40S TO AROUND 50. SOUTH WINDS AT 15
TO 20 MPH SHOULD KEEPS LOWS MILD.
LASTLY...THE MODELS SHOW A WEAK DISTURBANCE FIRING THUNDERSTORMS ON
THE LARAMIE AND FRONT RANGES LATE THIS AFTERNOON AROUND 21Z WHICH
CARRY EAST TOWARD WESTERN NEBRASKA. THE BEST GUESS IS FOR ISOLATED
SPRINKLES THIS EVENING. THE GFS WAS THE WET MODEL WHICH ACTUALLY
SHOWS SOME MEASURABLE QPF.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 359 AM CDT TUE MAY 12 2015
MODELS CONTINUE TO ADVERTISE A RAPID RETURN OF GULF MOISTURE TAKING
PLACE WEDNESDAY...WITH MODELS PROJECTING 850 MB DEW POINTS IN THE
10 TO 12C RANGE BY WEDNESDAY EVENING ACROSS THE REGION.
A LARGE UPPER TROUGH WILL BE TAKING SHAPE ALONG THE WEST COAST MID
TO LATE WEEK...WITH A LEAD SHORTWAVE EJECTING NORTHEAST THROUGH THE
PLAINS AHEAD OF THE TROUGH WEDNESDAY NIGHT INTO THURSDAY. THIS
SYSTEM IS SHOWN TO HAVE SOMEWHAT OF A NEGATIVE TILT...WHICH WILL
HELP DRAW MOISTURE WESTWARD INTO THE HIGH PLAINS. THE COMBINATION OF
STRONG LIFT AND MOISTURE TRANSPORT ON A SOUTHERLY LOW LEVEL
JET...CONTINUES TO GIVE CONFIDENCE THAT PRECIPITATION SHOULD RESULT
LATE WEDNESDAY AFTERNOON AND WEDNESDAY NIGHT. WILL MAINTAIN THE
LIKELY POPS ALONG AND EAST OF HIGHWAY 83 WEDNESDAY NIGHT...AND ALSO
INTRODUCE EVENING LIKELY POPS ALONG A SURFACE TROUGH ACROSS THE
PANHANDLE INTO THE WESTERN SANDHILLS.
THE LEAD WAVE QUICKLY PASSES AND MOVES NORTHEAST AWAY FROM THE AREA
THURSDAY. ATTENTION THEN TURNS TO THE LONG WAVE TROUGH ALONG THE
WEST COAST. MODELS/ENSEMBLES PROJECT THIS TO MOVE EAST AS A CLOSED
SYSTEM DURING THE WEEKEND. THE GENERAL CONSENSUS IN THE MODELS AND
ENSEMBLE MEAN IS FOR THE CENTER OF THE SYSTEM TO TRACK ACROSS
WYOMING INTO SOUTH DAKOTA. THIS PUTS OUR AREA IN THE WARM MOIST
SECTOR. INSTABILITY LOOKS TO BE STRONG...AND AS DEEP LAYER SHEAR
INCREASES...STRONG TO SEVERE STORMS WILL LIKELY RESULT. WILL
INTRODUCE THE POTENTIAL FOR SEVERE THUNDERSTORMS IN THE HAZARDOUS
WEATHER OUTLOOK FOR FRIDAY AND SATURDAY. THE GFS AND ECMWF CONTINUE
TO DIFFER SOMEWHAT ON THE LOW LEVEL BOUNDARY PLACEMENT...BUT THE
LATEST TREND IS TO HOLD THE DRY LINE BACK TO THE WEST ACROSS WESTERN
NEBRASKA INTO WESTERN KANSAS...WHICH WOULD PLACE SEVERE STORM
DEVELOPMENT ACROSS THE FORECAST AREA OF WESTERN AND NORTH CENTRAL
NEBRASKA. WE WILL LIKELY BE IN THE MIDST OF THE MID LEVEL DRY SLOT
SUNDAY AS THE STORM SYSTEM CROSSES THE DAKOTAS...BUT AT LEAST SOME
CHANCE FOR SHOWERS IN WRAP AROUND PATTERN ACROSS NORTHERN NEBRASKA.
DRY WEATHER FOR MONDAY...THEN MORE CHANCES FOR RAIN NEXT WEEK BEYOND
THE FORECAST PERIOD...AS THE NEXT DEEP TROUGH MOVES EAST INTO THE
WESTERN CONUS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1120 PM CDT MON MAY 11 2015
EXCEPT FOR A BRIEF PERIOD OF MIDDLE CLOUD CEILINGS 10-14Z...
UNLIMITED CEILING AND VISIBILITY ARE FORECAST TO CONTINUE
TONIGHT AND TUESDAY THROUGH LATE TUESDAY EVENING.
VARIABLE WIND IS EXPECTED TONIGHT AS HIGH PRESSURE DRIFTS TO THE
EAST AND WIND SWINGS AROUND TO THE SOUTH. WIND WILL INCREASE TUESDAY
MORNING AND...BY 15Z...IS EXPECTED TO BE 150-180 AT 12-15G20-24. THE
WIND IS THEN EXPECTED TO CONTINUE INCREASING...BECOMING 160-180 AT
18-22G28-32KT. AFTER 00Z...THE WIND WILL DECREASE TO 12-14G20-22KT.
&&
.HYDROLOGY...
ISSUED AT 359 AM CDT TUE MAY 12 2015
THE COMBINATION OF SEASONAL SNOW MELT IN THE UPPER SOUTH PLATTE
RIVER BASIN AND RECENT HEAVY PRECIPITATION OVER WESTERN NEBRASKA AND
NORTHEAST COLORADO WILL LEAD TO FLOODING ON THE SOUTH PLATTE AND
PLATTE RIVERS IN SOUTHWEST NEBRASKA LATER THIS WEEK AND INTO EARLY
NEXT WEEK. AT THIS TIME SOME UNCERTAINTY STILL REMAINS WITH THE
FORECAST AS KEY UPSTREAM GAUGES IN NORTHEAST COLORADO HAVE YET TO
CREST. HOWEVER...LATEST PROJECTIONS CONTINUE TO HIGHLIGHT AN
INCREASING THREAT FOR SIGNIFICANT FLOODING TO OCCUR...POTENTIALLY
NEAR SEPTEMBER 2013 FLOOD LEVELS.
RIVER STAGE FORECASTS WILL BE CLOSELY MONITORED AND UPDATED ONCE
MORE UPSTREAM RIVER DATA BECOMES AVAILABLE. PERSONS THAT LIVE IN
VULNERABLE AREAS ALONG THE SOUTH PLATTE RIVER AND PLATTE RIVER IN
SOUTHWEST NEBRASKA SHOULD PAY CLOSE ATTENTION TO FLOOD FORECASTS IN
THE COMING DAYS AND BE PREPARED TO TAKE PROPER ACTION.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY UNTIL 9 AM CDT /8 AM MDT/ THIS MORNING FOR
NEZ006>010-026>029-038-058-059-069>071.
FREEZE WARNING UNTIL 9 AM CDT /8 AM MDT/ THIS MORNING FOR NEZ004-
005-022>025-035>037-056-057-094.
&&
$$
SHORT TERM...CDC
LONG TERM...TAYLOR
AVIATION...SPRINGER
HYDROLOGY...MARTIN/TAYLOR
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1242 AM CDT TUE MAY 12 2015
.UPDATE...
ISSUED AT 1242 AM CDT TUE MAY 12 2015
TEMPS ARE FALLING SLOWLY AS WINDS ARE STILL 5-7 KTS MOST
LOCATIONS. 04Z HRRR INDICATES THE SFC RIDGE AXIS WILL MOVE THRU
RIGHT AROUND DAWN. WINDS SHOULD THEN DROP OFF AND ALLOW TEMPS TO
REACH THE LOW-MID 30S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 1242 AM CDT TUE MAY 12 2015
THIS SERVES AS THE FIRST DRAFT FOR THIS SHIFT...
ALOFT: HEIGHTS WILL CONT TO RISE TODAY. WNW FLOW WILL TRANSITION
TO WSW TONIGHT AS A SHORTWAVE RIDGE PASSES THRU.
SURFACE: HIGH PRES WAS OVER KS AT 08Z AND WILL DRIFT E OF THE
REGION TODAY. MEANWHILE...LOW PRES WILL CONT ORGANIZING OVER THE
INTERMOUNTAIN W THRU TONIGHT. RETURN FLOW WILL RESULT WITH A
TIGHTENING PRES GRAD.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 339 PM CDT MON MAY 11 2015
A LARGE AREA OF LOW PRESSURE WILL DROP SOUTH ACROSS THE WESTERN
STATES OVER THE MIDDLE OF THE WEEK...RESULTING IN GENERALLY
SOUTHWESTERLY FLOW ALOFT AND MULTIPLE CHANCES FOR THUNDERSTORMS
BEGINNING WEDNESDAY AFTERNOON. TEMPERATURE WISE...GENERALLY MILD
CONDITIONS ARE EXPECTED THROUGH THE EXTENDED PERIODS...WITH
TEMPERATURES EXPECTED TO BE NEAR OR ABOVE CLIMATOLOGY EACH DAY.
STARTING WEDNESDAY...EXPECT A WEAK UPPER LEVEL DISTURBANCE/OPEN
WAVE TO BE LIFTED NORTHWARD ACROSS THE PLAINS AS A LARGE AREA OF
LOW PRESSURE CIRCULATES ACROSS THE WESTERN STATES. WHILE SOUTHERLY
RETURN FLOW WILL HELP DEWPOINTS CLIMB BACK TO NEAR 50 BY WEDNESDAY
AFTERNOON...INSTABILITY WILL STILL BE VERY MARGINAL...SO OPTED TO
ONLY MENTION AN ISOLATED THUNDERSTORM WEDNESDAY/WEDNESDAY
NIGHT...WITH THE FOCUS OF THIS ACTIVITY SHIFTING SLIGHTLY EASTWARD
FROM PREVIOUS FORECASTS AS THE LLJ IS FORECAST TO BE FOCUSED JUST
EAST OF THE LOCAL AREA.
WHILE INSTABILITY VALUES WILL BE A LITTLE MORE RESPECTABLE ON
THURSDAY AFTERNOON...THE LACK OF ANY SIGNIFICANT FORCING MECHANISM
SHOULD HELP LIMIT ANY DEVELOPMENT TO PRIMARILY THE DAYTIME
HOURS... DEPENDING ON THE TIMING OF THE AFOREMENTIONED
DISTURBANCE...WITH DRY WEATHER ANTICIPATED THURSDAY NIGHT INTO
FRIDAY MORNING.
THEREAFTER...INSTABILITY WILL INCREASE SIGNIFICANTLY ACROSS THE
LOCAL AREA WITH MULTIPLE DISTURBANCES PASSING OUT OF THE LONGWAVE
TROUGH. THIS SHOULD RESULT IN MORE WIDESPREAD SHOWER AND
THUNDERSTORM ACTIVITY ACROSS THE LOCAL AREA FOR THE END OF THE
WEEK AND START OF THE UPCOMING WEEKEND. IN ADDITION...WITH A
MODEST LLJ EXPECTED TO DEVELOP EACH NIGHT...INCREASING SHEAR
VALUES...AND MULTIPLE PASSING UPPER LEVEL DISTURBANCES...EXPECT
THE POTENTIAL FOR SOME SEVERE WEATHER TO RETURN ON FRIDAY AND
SATURDAY...WITH THE LOCAL AREA NOW HIGHLIGHTED FOR A CHANCE OF
SEVERE WEATHER BY SPC IN THEIR DAY 5 AND DAY 6 FORECASTS.
COULD SEE A BREAK IN SHOWER AND THUNDERSTORM ACTIVITY LATE IN THE
UPCOMING WEEKEND AND EARLY NEXT WEEK AS A SHORTWAVE TROUGH
TRANSITIONS ACROSS THE PLAINS...BUT MODELS ARE HINTING AT YET
ANOTHER UPPER LEVEL LOW EMERGING FROM THE SOUTHWEST EARLY NEXT
WEEK WHICH COULD AFFECT THE LOCAL AREA JUST BEYOND THE CURRENT
SCOPE OF THE EXTENDED FORECAST.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z TUE NIGHT)
ISSUED AT 1242 AM CDT TUE MAY 12 2015
REST OF TONIGHT: VFR SKC. LIGHT W WINDS WILL BECOME LGT AND VRBL.
CONFIDENCE: HIGH
TUE: VFR WITH A PERIOD OF PATCHY OF 7K FT SCT CLOUDS. WINDS BECOME
S AND WILL GUST 20-27 KTS WITH POTENTIAL FOR 32 KTS. CONFIDENCE:
HIGH
TUE EVE: VFR. S WINDS BECOME SSE AND WILL CONT TO GUST UP TO 25
KTS AT TIMES. HAVE INCLUDED LLWS TO COVER PERIODIC LULLS IN SFC
WINDS. CONFIDENCE: HIGH
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...FROST ADVISORY UNTIL 9 AM CDT THIS MORNING FOR NEZ039-040-046-
047-060>062-072>075-082>085.
KS...FROST ADVISORY UNTIL 9 AM CDT THIS MORNING FOR KSZ005>007-
017>019.
&&
$$
UPDATE...HALBLAUB
SHORT TERM...HALBLAUB
LONG TERM...ROSSI
AVIATION...HALBLAUB
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
646 PM EDT TUE MAY 12 2015
.SYNOPSIS...
SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED LATE
TODAY AHEAD OF A COLD FRONT TONIGHT. LESS HUMID AIR WILL ARRIVE
WEDNESDAY AND SHOULD LAST INTO THURSDAY AS HIGH PRESSURE MOVES
OVERHEAD. THE LATTER PART OF THE WEEK AND WEEKEND WILL FEATURE A
GRADUAL INCREASE IN HUMIDITY AND THUNDERSTORM CHANCES AS THE HIGH
MOVES OFF THE COAST.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 620 PM TUESDAY...SOME RE-ADJUSTMENTS OF THIS EVENING AND
OVERNIGHT POPS BASED ON LATEST TSTORM ACTIVITY BREAKING OUT ACROSS
THE EXTREME WESTERN PORTIONS OF THE ILM CWA AHEAD OF THE
APPROACHING COLD FRONT. IF THE ACTIVITY HOLDS TOGETHER AS IT
PUSHES EASTWARD...AND MEETS UP WITH THE SEA BREEZE...FURTHER
ACTIVITY COULD BLOSSOM. ALTHOUGH AT THIS TIME VIA KLTX 88D AND
VIS SAT IMAGERY...IT LOOKS LIKE THE SEA BREEZE HAS REACHED ITS
MAXIMUM PUSH INLAND. STILL...ENOUGH SFC FORCING SHOULD AID
CONTINUING THE CONVECTION AS IT PUSHES EASTWARD BEFORE THE MARINE
INFLUENCES BEHIND THE SEA BREEZE LIKELY PARTIALLY OR ENTIRELY
EXTINGUISHES IT. OVERALL...KEPT POPS IN THE LOWER CHANCE CATEGORY.
CURRENT MIN TEMP FORECAST LOOKS AOK...NO CHANGES NEEDED AT THIS
TIME.
PREVIOUS......................................................
AS OF 318 PM TUESDAY...VERY HOT DAY ONGOING ACROSS THE CWA WITH
LOTS OF 90-91 READINGS AND MID 60S TO AROUND 70 DEWPOINTS. THE SEA
BREEZE IS CLEARLY EVIDENT AS A LINE OF MODERATE CU FROM ABOUT
BURGAW TO TABOR CITY TO GEORGETOWN...MAKING MUCH MORE PROGRESS NW
INTO NC ON THE RESULTANT. THIS WILL CONTINUE TO SLOWLY PUSH WEST
THIS AFTN...BUT BASED OFF THE STRUGGLE OF THE CU TO GAIN VERTICAL
DEPTH...HAVE CUT BACK POP TO JUST A VERY ISOLATED SHOWER ALONG THE
SEA BREEZE.
PRE-FRONTAL TROUGH WILL APPROACH THIS EVENING AND IS LIKELY TO BE
OUR ONLY CHANCE FOR TSTMS TODAY. HRRR IS ALL OF A SUDDEN VERY
AGGRESSIVE WITH CONVECTION ALONG IT THIS EVENING AND RACING EAST
OFFSHORE EARLY IN THE NIGHTTIME PERIOD. WHILE THIS TIMING IS
APPROPRIATE...HAVE A HARD TIME PLACING MORE THAN 40 POP ANYWHERE FOR
ISOLATED TO SCATTERED TSTMS...MORE LIKE THE WRF SOLUTION. THINK THE
MID-LEVELS ARE JUST A BIT TOO WARM FOR STRONG CONVECTION...BUT THE
SPC SWODY1 MAINTAINS A MRGL RISK FOR OUR NC ZONES AND CANNOT RULE
OUT AN ISOLATED WIND GUST AS INVERTED-V SOUNDINGS ARE FORECAST AHEAD
OF THIS TROUGH.
PRE-FRONTAL TROUGH WILL MOVE OFFSHORE...AND THEN SUBSEQUENT COLD
FRONT WILL THEN TRAVERSE THE CWA LATE TONIGHT...MOVING OFFSHORE BY
DAWN WEDNESDAY. NO CONVECTION EXPECTED ALONG THE BOUNDARY...BUT A
SIGNIFICANT AIR MASS CHANGE WITH QUICKLY COOLING TEMPS AND MUCH
DRIER DEWPOINTS WILL OCCUR. LOWS TONIGHT WILL RANGE FROM AROUND 60
WELL INLAND...TO ABOUT 65 AT THE COAST.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 318 PM TUESDAY...CHANGING OF THE GUARD SO TO SPEAK IN TERMS
OF AIR MASS REPLACEMENT THIS PERIOD...AS A COLD FRONT MIGRATES
OFF THE COAST AROUND DAYBREAK WEDNESDAY. POST FRONTAL N WIND WILL
TEND TO NE WEDNESDAY ACCOMPANIED BY LOWERING DEWPOINTS IN THE 50S
MAKING FOR CONSIDERABLY LESS MUGGINESS...WITH MAXIMUMS OF UPPER
70S TO LOWER 80S WITH SUN. EARLY THURSDAY SEASONABLY COOL MINIMUMS
OF UPPER 50S TO LOWER 60S...MILDEST COAST. A COOLER DAY SETTING UP
THURSDAY AS HIGH PRESSURE FROM THE GREAT LAKES DROPS SOUTHEAST
TOWARD THE CAROLINAS...SUPPLYING A DOSE OF COOL AIR ADVECTION.
MINIMUMS EARLY FRIDAY SIMILAR TO THURSDAY UPPER 50S TO LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 318 PM TUESDAY...TRANSITION PERIOD AS HIGH PRESSURE MOVES
OFFSHORE FRIDAY AND RETURN FLOW RESUMES ACROSS THE AREA. THIS
WILL BRING A TREND UPWARD IN TEMPERATURES AND HUMIDITY WITH AN
INCREASING CHANCE OF SHOWERS/TSTMS AS A COLD FRONT GRADUALLY
APPROACHES FROM THE WEST THIS WEEKEND. THE FRONT MAY STALL OVER
THE AREA EARLY NEXT WEEK...OFFERING HIGH HUMIDITY AND EVEN A
BETTER CHANCE OF PCPN INTO EARLY NEXT WEEK. THIS REGIME SHOULD
RESULT IN TEMPERATURES NEAR OR SLIGHTLY ABOVE CLIMATE STANDARDS
FOR MIDDLE MAY.
&&
.AVIATION /00Z WEDNESDAY THROUGH MONDAY/...
AS OF 18Z...SOME ISOLATED CONVECTION IS TRYING TO FORM AHEAD OF A
COLD FRONT THAT WILL SWING THROUGH THE REGION OVERNIGHT. SINCE WE
ARE LOSING OUR AFTERNOON HEATING...DO NOT THINK THE CONVECTION WILL
GET BETTER ORGANIZED BUT THERE COULD BE A BRIEF BUMP UP AS THE
CONVECTION ENCOUNTERS THE SEA BREEZE BOUNDARY IN A COUPLE OF HOURS.
OVERNIGHT...LOOK FOR ANY LEFTOVER CONVECTION TO REACH THE COAST BY
05Z. WINDS WILL SHIFT TO THE NORTH BEHIND THE COLD FRONT AFTER
MIDNIGHT...WITH MODERATE NORTHEAST FLOW EXPECTED FOR WEDNESDAY WITH
LESS HUMID CONDITIONS.
EXTENDED OUTLOOK...VFR. SCATTERED SHOWERS FRIDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 PM TUESDAY...SSW-SW WINDS 15 TO 20 KT TO PREVAIL WELL
INTO TONIGHT...DIMINISHING TO 10-15 KT AS THE COLD FRONT
APPROACHES...AND LIKELY VEERING TO THE NW-N AROUND 15 KT BY
DAYBREAK WED AFTER FROPA. SIGNIFICANT SEAS WILL RUN 2 TO 4
FT...HIEST ACROSS THE WATERS FROM CAPE FEAR SOUTH TO LITTLE RIVER
INLET WHERE THE FETCH IS GREATEST GIVEN THE WIND DIRECTION. A 1 TO
2 FOOT 7-8 SECOND PERIOD GROUND SWELL REMAINS IDENTIFIABLE...BUT
WIND DRIVEN WAVES AT 4 TO 5 SECONDS WILL DOMINATE THE SIGNIFICANT
SEAS.
PREVIOUS.....................................................
AS OF 318 PM TUESDAY...HIGH PRESSURE OFFSHORE CONTINUES TO DRIVE
SW WINDS ACROSS THE WATERS THIS AFTN. SPEEDS ARE GENERALLY AROUND
15 KTS...BUT ARE REACHING 20 KTS WITH SOME BACKING TO THE SOUTH
NEAR THE COAST THANKS TO THE LOCAL SEA BREEZE ENHANCEMENT. THE SEA
BREEZE WILL EASE WITH LOSS OF HEATING...LEAVING 15 KT WINDS ACROSS
THE WATERS TONIGHT...ALONG WITH PERSISTENT 2-4 FT SEAS. THE WAVE
PERIOD WILL BE AROUND 7 SEC...SHORTER IN THE MORE WIND-DRIVEN SEA
BREEZE NEAR SHORE. A COLD FRONT WILL CROSS THE WATERS TOWARDS DAWN
ON WEDNESDAY...TURNING THE WINDS QUICKLY TO THE N/NW AND DRIVING
THE HIGHER WAVES AWAY FROM SHORE. A FEW SHOWERS AND TSTMS MAY
ACCOMPANY THIS FRONT...BUT WIDESPREAD CONVECTION IS NOT CURRENTLY
ANTICIPATED.
SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 318 PM TUESDAY...A COLD FRONTAL PASSAGE TO BRING A
WINDSHIFT TO NORTH ON THE WATERS WEDNESDAY...TENDING TO NE AND ENE
HEADING INTO LATER WEDNESDAY AND THURSDAY. NO ADVISORIES BUT NE GUSTS
TO 20 KT EXPECTED EARLY THURSDAY AS HIGH PRESSURE BUILDS FROM THE
NW. SEAS 2-3 FEET WEDNESDAY WILL BUILD TO 3-4 FEET THURSDAY. NO
TSTMS OR VISIBILITY RESTRICTIONS ON THE 0-20 NM WATERS EXPECTED
WED/THU/
.LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 318 PM TUESDAY...A TRANSITION TO A BERMUDA HIGH PRESSURE
PATTERN AS HIGH PRESSURE MOVES OFFSHORE AND RETURN SW WINDS PREVAIL
BEGINNING FRIDAY AND PERSISTING THROUGH THE WEEKEND. WARMING
DAYTIME TEMPERATURES WILL DRIVE A SEA BREEZE AND AFTERNOON GUSTS
TO 20 KT SHOULD BE EXPECTED NEAR SHORE OVER THE WEEKEND. ISOLATED
SHOWERS AND TSTMS SHOULD ALSO BE EXPECTED INTO THE WEEKEND AS S
AND SW WINDS INTRODUCE ADDITIONAL MOISTURE INTO THE REGION.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MJC
NEAR TERM...DCH/JDW
SHORT TERM...MJC
LONG TERM...SHK
AVIATION...DL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
642 PM EDT TUE MAY 12 2015
.SYNOPSIS...
SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED LATE
TODAY AHEAD OF A COLD FRONT TONIGHT. LESS HUMID AIR WILL ARRIVE
WEDNESDAY AND SHOULD LAST INTO THURSDAY AS HIGH PRESSURE MOVES
OVERHEAD. THE LATTER PART OF THE WEEK AND WEEKEND WILL FEATURE A
GRADUAL INCREASE IN HUMIDITY AND THUNDERSTORM CHANCES AS THE HIGH
MOVES OFF THE COAST.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 620 PM TUESDAY...SOME RE-ADJUSTMENTS OF THIS EVENING AND
OVERNIGHT POPS BASED ON LATEST TSTORM ACTIVITY BREAKING OUT ACROSS
THE EXTREME WESTERN PORTIONS OF THE ILM CWA AHEAD OF THE
APPROACHING COLD FRONT. IF THE ACTIVITY HOLDS TOGETHER AS IT
PUSHES EASTWARD...AND MEETS UP WITH THE SEA BREEZE...FURTHER
ACTIVITY COULD BLOSSOM. ALTHOUGH AT THIS TIME VIA KLTX 88D AND
VIS SAT IMAGERY...IT LOOKS LIKE THE SEA BREEZE HAS REACHED ITS
MAXIMUM PUSH INLAND. STILL...ENOUGH SFC FORCING SHOULD AID
CONTINUING THE CONVECTION AS IT PUSHES EASTWARD BEFORE THE MARINE
INFLUENCES BEHIND THE SEA BREEZE LIKELY PARTIALLY OR ENTIRELY
EXTINGUISHES IT. OVERALL...KEPT POPS IN THE LOWER CHANCE CATEGORY.
CURRENT MIN TEMP FORECAST LOOKS AOK...NO CHANGES NEEDED AT THIS
TIME.
PREVIOUS......................................................
AS OF 318 PM TUESDAY...VERY HOT DAY ONGOING ACROSS THE CWA WITH
LOTS OF 90-91 READINGS AND MID 60S TO AROUND 70 DEWPOINTS. THE SEA
BREEZE IS CLEARLY EVIDENT AS A LINE OF MODERATE CU FROM ABOUT
BURGAW TO TABOR CITY TO GEORGETOWN...MAKING MUCH MORE PROGRESS NW
INTO NC ON THE RESULTANT. THIS WILL CONTINUE TO SLOWLY PUSH WEST
THIS AFTN...BUT BASED OFF THE STRUGGLE OF THE CU TO GAIN VERTICAL
DEPTH...HAVE CUT BACK POP TO JUST A VERY ISOLATED SHOWER ALONG THE
SEA BREEZE.
PRE-FRONTAL TROUGH WILL APPROACH THIS EVENING AND IS LIKELY TO BE
OUR ONLY CHANCE FOR TSTMS TODAY. HRRR IS ALL OF A SUDDEN VERY
AGGRESSIVE WITH CONVECTION ALONG IT THIS EVENING AND RACING EAST
OFFSHORE EARLY IN THE NIGHTTIME PERIOD. WHILE THIS TIMING IS
APPROPRIATE...HAVE A HARD TIME PLACING MORE THAN 40 POP ANYWHERE FOR
ISOLATED TO SCATTERED TSTMS...MORE LIKE THE WRF SOLUTION. THINK THE
MID-LEVELS ARE JUST A BIT TOO WARM FOR STRONG CONVECTION...BUT THE
SPC SWODY1 MAINTAINS A MRGL RISK FOR OUR NC ZONES AND CANNOT RULE
OUT AN ISOLATED WIND GUST AS INVERTED-V SOUNDINGS ARE FORECAST AHEAD
OF THIS TROUGH.
PRE-FRONTAL TROUGH WILL MOVE OFFSHORE...AND THEN SUBSEQUENT COLD
FRONT WILL THEN TRAVERSE THE CWA LATE TONIGHT...MOVING OFFSHORE BY
DAWN WEDNESDAY. NO CONVECTION EXPECTED ALONG THE BOUNDARY...BUT A
SIGNIFICANT AIR MASS CHANGE WITH QUICKLY COOLING TEMPS AND MUCH
DRIER DEWPOINTS WILL OCCUR. LOWS TONIGHT WILL RANGE FROM AROUND 60
WELL INLAND...TO ABOUT 65 AT THE COAST.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 318 PM TUESDAY...CHANGING OF THE GUARD SO TO SPEAK IN TERMS
OF AIR MASS REPLACEMENT THIS PERIOD...AS A COLD FRONT MIGRATES
OFF THE COAST AROUND DAYBREAK WEDNESDAY. POST FRONTAL N WIND WILL
TEND TO NE WEDNESDAY ACCOMPANIED BY LOWERING DEWPOINTS IN THE 50S
MAKING FOR CONSIDERABLY LESS MUGGINESS...WITH MAXIMUMS OF UPPER
70S TO LOWER 80S WITH SUN. EARLY THURSDAY SEASONABLY COOL MINIMUMS
OF UPPER 50S TO LOWER 60S...MILDEST COAST. A COOLER DAY SETTING UP
THURSDAY AS HIGH PRESSURE FROM THE GREAT LAKES DROPS SOUTHEAST
TOWARD THE CAROLINAS...SUPPLYING A DOSE OF COOL AIR ADVECTION.
MINIMUMS EARLY FRIDAY SIMILAR TO THURSDAY UPPER 50S TO LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 318 PM TUESDAY...TRANSITION PERIOD AS HIGH PRESSURE MOVES
OFFSHORE FRIDAY AND RETURN FLOW RESUMES ACROSS THE AREA. THIS
WILL BRING A TREND UPWARD IN TEMPERATURES AND HUMIDITY WITH AN
INCREASING CHANCE OF SHOWERS/TSTMS AS A COLD FRONT GRADUALLY
APPROACHES FROM THE WEST THIS WEEKEND. THE FRONT MAY STALL OVER
THE AREA EARLY NEXT WEEK...OFFERING HIGH HUMIDITY AND EVEN A
BETTER CHANCE OF PCPN INTO EARLY NEXT WEEK. THIS REGIME SHOULD
RESULT IN TEMPERATURES NEAR OR SLIGHTLY ABOVE CLIMATE STANDARDS
FOR MIDDLE MAY.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
AS OF 18Z...THE SEA BREEZE HAS DEVELOPED WITH PRETTY MUCH A STEADY
S-SSW WIND AROUND 13KT AT THE COASTAL TERMINALS. WINDS AT
KFLO/KLBT ARE SW 8-12KT. TERMINALS ARE VFR...AND THE IFR CIGS JUST
NORTH OF CRE SHOULD REMAIN JUST AWAY FROM THE TERMINAL. CONFIDENCE
IS MODERATE TO HIGH KCRE WILL REMAIN VFR.
A COLD FRONT WILL APPROACH AND MOVE THROUGH THE TERMINALS THIS TAF
PERIOD. IT WILL BE UNSTABLE ENOUGH FOR SHOWERS AND THUNDERSTORMS TO
DEVELOP THIS EVENING. APPEARS THE BEST AREA FOR DEVELOPMENT WILL BE
BETWEEN THE INLAND AND COASTAL TERMINALS WHERE SURFACE WINDS ARE
CONVERGING...AND LATEST HIGH RES GUIDANCE SUGGESTS THIS WILL NOT
EVEN REACH THE COASTAL TERMINALS AS IT STABILIZES BEHIND THE SEA
BREEZE. CONVECTION SHOULD TAPER OFF IN THE EVENING. THE COLD FRONT
WILL MOVE THROUGH DURING OVERNIGHT HOURS. PRECIPITATION WILL DROP
AFTER THE FRONT MOVES THROUGH. VFR WILL CONTINUE INTO THE MORNING
HOURS WITH VFR/NE WINDS AFTER SUNRISE.
EXTENDED OUTLOOK...VFR. SCATTERED SHOWERS FRIDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 630 PM TUESDAY...SSW-SW WINDS 15 TO 20 KT TO PREVAIL WELL
INTO TONIGHT...DIMINISHING TO 10-15 KT AS THE COLD FRONT
APPROACHES...AND LIKELY VEERING TO THE NW-N AROUND 15 KT BY
DAYBREAK WED AFTER FROPA. SIGNIFICANT SEAS WILL RUN 2 TO 4
FT...HIEST ACROSS THE WATERS FROM CAPE FEAR SOUTH TO LITTLE RIVER
INLET WHERE THE FETCH IS GREATEST GIVEN THE WIND DIRECTION. A 1 TO
2 FOOT 7-8 SECOND PERIOD GROUND SWELL REMAINS IDENTIFIABLE...BUT
WIND DRIVEN WAVES AT 4 TO 5 SECONDS WILL DOMINATE THE SIGNIFICANT
SEAS.
PREVIOUS.....................................................
AS OF 318 PM TUESDAY...HIGH PRESSURE OFFSHORE CONTINUES TO DRIVE
SW WINDS ACROSS THE WATERS THIS AFTN. SPEEDS ARE GENERALLY AROUND
15 KTS...BUT ARE REACHING 20 KTS WITH SOME BACKING TO THE SOUTH
NEAR THE COAST THANKS TO THE LOCAL SEA BREEZE ENHANCEMENT. THE SEA
BREEZE WILL EASE WITH LOSS OF HEATING...LEAVING 15 KT WINDS ACROSS
THE WATERS TONIGHT...ALONG WITH PERSISTENT 2-4 FT SEAS. THE WAVE
PERIOD WILL BE AROUND 7 SEC...SHORTER IN THE MORE WIND-DRIVEN SEA
BREEZE NEAR SHORE. A COLD FRONT WILL CROSS THE WATERS TOWARDS DAWN
ON WEDNESDAY...TURNING THE WINDS QUICKLY TO THE N/NW AND DRIVING
THE HIGHER WAVES AWAY FROM SHORE. A FEW SHOWERS AND TSTMS MAY
ACCOMPANY THIS FRONT...BUT WIDESPREAD CONVECTION IS NOT CURRENTLY
ANTICIPATED.
SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 318 PM TUESDAY...A COLD FRONTAL PASSAGE TO BRING A
WINDSHIFT TO NORTH ON THE WATERS WEDNESDAY...TENDING TO NE AND ENE
HEADING INTO LATER WEDNESDAY AND THURSDAY. NO ADVISORIES BUT NE GUSTS
TO 20 KT EXPECTED EARLY THURSDAY AS HIGH PRESSURE BUILDS FROM THE
NW. SEAS 2-3 FEET WEDNESDAY WILL BUILD TO 3-4 FEET THURSDAY. NO
TSTMS OR VISIBILITY RESTRICTIONS ON THE 0-20 NM WATERS EXPECTED
WED/THU/
.LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 318 PM TUESDAY...A TRANSITION TO A BERMUDA HIGH PRESSURE
PATTERN AS HIGH PRESSURE MOVES OFFSHORE AND RETURN SW WINDS PREVAIL
BEGINNING FRIDAY AND PERSISTING THROUGH THE WEEKEND. WARMING
DAYTIME TEMPERATURES WILL DRIVE A SEA BREEZE AND AFTERNOON GUSTS
TO 20 KT SHOULD BE EXPECTED NEAR SHORE OVER THE WEEKEND. ISOLATED
SHOWERS AND TSTMS SHOULD ALSO BE EXPECTED INTO THE WEEKEND AS S
AND SW WINDS INTRODUCE ADDITIONAL MOISTURE INTO THE REGION.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MJC
NEAR TERM...DCH/JDW
SHORT TERM...MJC
LONG TERM...SHK
AVIATION...DL
AREA FORECAST DISCUSSION...COR
NWS WILMINGTON NC
318 PM EDT TUE MAY 12 2015
.SYNOPSIS...
SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE EXPECTED LATE
TODAY AHEAD OF A COLD FRONT TONIGHT. LESS HUMID AIR WILL ARRIVE
WEDNESDAY AND SHOULD LAST INTO THURSDAY AS HIGH PRESSURE MOVES
OVERHEAD. THE LATTER PART OF THE WEEK AND WEEKEND WILL FEATURE A
GRADUAL INCREASE IN HUMIDITY AND THUNDERSTORM CHANCES AS THE HIGH
MOVES OFF THE COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 318 PM TUESDAY...VERY HOT DAY ONGOING ACROSS THE CWA WITH
LOTS OF 90-91 READINGS AND MID 60S TO AROUND 70 DEWPOINTS. THE SEA
BREEZE IS CLEARLY EVIDENT AS A LINE OF MODERATE CU FROM ABOUT
BURGAW TO TABOR CITY TO GEORGETOWN...MAKING MUCH MORE PROGRESS NW
INTO NC ON THE RESULTANT. THIS WILL CONTINUE TO SLOWLY PUSH WEST
THIS AFTN...BUT BASED OFF THE STRUGGLE OF THE CU TO GAIN VERTICAL
DEPTH...HAVE CUT BACK POP TO JUST A VERY ISOLATED SHOWER ALONG THE
SEA BREEZE.
PRE-FRONTAL TROUGH WILL APPROACH THIS EVENING AND IS LIKELY TO BE
OUR ONLY CHANCE FOR TSTMS TODAY. HRRR IS ALL OF A SUDDEN VERY
AGGRESSIVE WITH CONVECTION ALONG IT THIS EVENING AND RACING EAST
OFFSHORE EARLY IN THE NIGHTTIME PERIOD. WHILE THIS TIMING IS
APPROPRIATE...HAVE A HARD TIME PLACING MORE THAN 40 POP ANYWHERE FOR
ISOLATED TO SCATTERED TSTMS...MORE LIKE THE WRF SOLUTION. THINK THE
MID-LEVELS ARE JUST A BIT TOO WARM FOR STRONG CONVECTION...BUT THE
SPC SWODY1 MAINTAINS A MRGL RISK FOR OUR NC ZONES AND CANNOT RULE
OUT AN ISOLATED WIND GUST AS INVERTED-V SOUNDINGS ARE FORECAST AHEAD
OF THIS TROUGH.
PRE-FRONTAL TROUGH WILL MOVE OFFSHORE...AND THEN SUBSEQUENT COLD
FRONT WILL THEN TRAVERSE THE CWA LATE TONIGHT...MOVING OFFSHORE BY
DAWN WEDNESDAY. NO CONVECTION EXPECTED ALONG THE BOUNDARY...BUT A
SIGNIFICANT AIR MASS CHANGE WITH QUICKLY COOLING TEMPS AND MUCH
DRIER DEWPOINTS WILL OCCUR. LOWS TONIGHT WILL RANGE FROM AROUND 60
WELL INLAND...TO ABOUT 65 AT THE COAST.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 318 PM TUESDAY...CHANGING OF THE GUARD SO TO SPEAK IN TERMS
OF AIR MASS REPLACEMENT THIS PERIOD...AS A COLD FRONT MIGRATES
OFF THE COAST AROUND DAYBREAK WEDNESDAY. POST FRONTAL N WIND WILL
TEND TO NE WEDNESDAY ACCOMPANIED BY LOWERING DEWPOINTS IN THE 50S
MAKING FOR CONSIDERABLY LESS MUGGINESS...WITH MAXIMUMS OF UPPER
70S TO LOWER 80S WITH SUN. EARLY THURSDAY SEASONABLY COOL MINIMUMS
OF UPPER 50S TO LOWER 60S...MILDEST COAST. A COOLER DAY SETTING UP
THURSDAY AS HIGH PRESSURE FROM THE GREAT LAKES DROPS SOUTHEAST
TOWARD THE CAROLINAS...SUPPLYING A DOSE OF COOL AIR ADVECTION.
MINIMUMS EARLY FRIDAY SIMILAR TO THURSDAY UPPER 50S TO LOWER 60S.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 318 PM TUESDAY...TRANSITION PERIOD AS HIGH PRESSURE MOVES
OFFSHORE FRIDAY AND RETURN FLOW RESUMES ACROSS THE AREA. THIS
WILL BRING A TREND UPWARD IN TEMPERATURES AND HUMIDITY WITH AN
INCREASING CHANCE OF SHOWERS/TSTMS AS A COLD FRONT GRADUALLY
APPROACHES FROM THE WEST THIS WEEKEND. THE FRONT MAY STALL OVER
THE AREA EARLY NEXT WEEK...OFFERING HIGH HUMIDITY AND EVEN A
BETTER CHANCE OF PCPN INTO EARLY NEXT WEEK. THIS REGIME SHOULD
RESULT IN TEMPERATURES NEAR OR SLIGHTLY ABOVE CLIMATE STANDARDS
FOR MIDDLE MAY.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
AS OF 18Z...THE SEA BREEZE HAS DEVELOPED WITH PRETTY MUCH A STEADY
S-SSW WIND AROUND 13KT AT THE COASTAL TERMINALS. WINDS AT
KFLO/KLBT ARE SW 8-12KT. TERMINALS ARE VFR...AND THE IFR CIGS JUST
NORTH OF CRE SHOULD REMAIN JUST AWAY FROM THE TERMINAL. CONFIDENCE
IS MODERATE TO HIGH KCRE WILL REMAIN VFR.
A COLD FRONT WILL APPROACH AND MOVE THROUGH THE TERMINALS THIS TAF
PERIOD. IT WILL BE UNSTABLE ENOUGH FOR SHOWERS AND THUNDERSTORMS TO
DEVELOP THIS EVENING. APPEARS THE BEST AREA FOR DEVELOPMENT WILL BE
BETWEEN THE INLAND AND COASTAL TERMINALS WHERE SURFACE WINDS ARE
CONVERGING...AND LATEST HIGH RES GUIDANCE SUGGESTS THIS WILL NOT
EVEN REACH THE COASTAL TERMINALS AS IT STABILIZES BEHIND THE SEA
BREEZE. CONVECTION SHOULD TAPER OFF IN THE EVENING. THE COLD FRONT
WILL MOVE THROUGH DURING OVERNIGHT HOURS. PRECIPITATION WILL DROP
AFTER THE FRONT MOVES THROUGH. VFR WILL CONTINUE INTO THE MORNING
HOURS WITH VFR/NE WINDS AFTER SUNRISE.
EXTENDED OUTLOOK...VFR. SCATTERED SHOWERS FRIDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 318 PM TUESDAY...HIGH PRESSURE OFFSHORE CONTINUES TO DRIVE
SW WINDS ACROSS THE WATERS THIS AFTN. SPEEDS ARE GENERALLY AROUND
15 KTS...BUT ARE REACHING 20 KTS WITH SOME BACKING TO THE SOUTH
NEAR THE COAST THANKS TO THE LOCAL SEA BREEZE ENHANCEMENT. THE SEA
BREEZE WILL EASE WITH LOSS OF HEATING...LEAVING 15 KT WINDS ACROSS
THE WATERS TONIGHT...ALONG WITH PERSISTENT 2-4 FT SEAS. THE WAVE
PERIOD WILL BE AROUND 7 SEC...SHORTER IN THE MORE WIND-DRIVEN SEA
BREEZE NEAR SHORE. A COLD FRONT WILL CROSS THE WATERS TOWARDS DAWN
ON WEDNESDAY...TURNING THE WINDS QUICKLY TO THE N/NW AND DRIVING
THE HIGHER WAVES AWAY FROM SHORE. A FEW SHOWERS AND TSTMS MAY
ACCOMPANY THIS FRONT...BUT WIDESPREAD CONVECTION IS NOT CURRENTLY
ANTICIPATED.
SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 318 PM TUESDAY...A COLD FRONTAL PASSAGE TO BRING A
WINDSHIFT TO NORTH ON THE WATERS WEDNESDAY...TENDING TO NE AND ENE
HEADING INTO LATER WEDNESDAY AND THURSDAY. NO ADVISORIES BUT NE GUSTS
TO 20 KT EXPECTED EARLY THURSDAY AS HIGH PRESSURE BUILDS FROM THE
NW. SEAS 2-3 FEET WEDNESDAY WILL BUILD TO 3-4 FEET THURSDAY. NO
TSTMS OR VISIBILITY RESTRICTIONS ON THE 0-20 NM WATERS EXPECTED
WED/THU/
.LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 318 PM TUESDAY...A TRANSITION TO A BERMUDA HIGH PRESSURE
PATTERN AS HIGH PRESSURE MOVES OFFSHORE AND RETURN SW WINDS PREVAIL
BEGINNING FRIDAY AND PERSISTING THROUGH THE WEEKEND. WARMING
DAYTIME TEMPERATURES WILL DRIVE A SEA BREEZE AND AFTERNOON GUSTS
TO 20 KT SHOULD BE EXPECTED NEAR SHORE OVER THE WEEKEND. ISOLATED
SHOWERS AND TSTMS SHOULD ALSO BE EXPECTED INTO THE WEEKEND AS S
AND SW WINDS INTRODUCE ADDITIONAL MOISTURE INTO THE REGION.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...JDW
SHORT TERM...MJC
LONG TERM...MJC
AVIATION...MRR/JDW
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
124 PM EDT TUE MAY 12 2015
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY AHEAD OF A
COLD FRONT. LESS HUMID AIR ARRIVES ON WEDNESDAY AND SHOULD LAST INTO
THURSDAY AS HIGH PRESSURE MOVES OVERHEAD. THE LATTER PART OF THE
WEEK AND WEEKEND WILL FEATURE A GRADUAL INCREASE IN HUMIDITY AND
THUNDERSTORM CHANCES AS THE HIGH MOVES OFF THE COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM TUESDAY...HOT AND HUMID DAY ONGOING ACROSS THE CWA
EVEN AT THIS EARLY HOUR. AFTER STARTING FROM LOWS AROUND 70...TEMPS
ARE SHOOTING UP QUICKLY THIS MORNING THANKS TO 950MB TEMPS CLOSE TO
22C ON THE 8AM KCHS U/A SOUNDING. HIGH PRESSURE CENTERED WELL
OFFSHORE IS PUMPING RETURN FLOW INTO THE CAROLINAS...WHICH IS
STRENGTHENING WARM ADVECTION IN A PRE-FRONTAL AIRMASS. THE
COMBINATION OF THIS HEAT AND DEWPOINT TEMPS AROUND 70 WILL DRIVE
HEAT INDICES INTO THE MID 90S AWAY FROM THE COAST TODAY...THE MOST
UNCOMFORTABLE DAY OF 2015 SO FAR.
THIS HUMID AIR MASS WILL DRIVE INSTABILITY THIS AFTN...AND
CONVECTION IS ONCE AGAIN EXPECTED ACROSS THE AREA. VERY STEEP LR`S
UP TO 800MB WILL DRIVE RAPID UPDRAFTS...AND SBCAPE IS FORECAST TO
RISE TO AROUND 3000 J/KG...POSSIBLY HIGHER RIGHT ALONG THE SEA
BREEZE. THIS WILL SERVE AS THE FUEL FOR STORMS TODAY...WHICH SHOULD
DEVELOP ALONG THE SEA BREEZE...AND THEN LATER ALONG A PRE-FRONTAL
TROUGH APPROACHING FROM THE WEST. WHILE RESIDUAL BOUNDARIES MAY FIRE
WEAK STORMS...MID LEVEL TEMPS ARE NOT EXCEEDINGLY COOL (-8C AT
500MB) SO WIDESPREAD STRONG UPDRAFTS ARE NOT ANTICIPATED.
STILL...ENOUGH FORCING WILL DRIVE PARCELS UP INTO DECENT HAIL-ZONE
INSTABILITY...AND AN INVERTED-V TYPE SIGNATURE IS PROGGED WELL
INLAND AHEAD OF THE PRE-FRONTAL TROUGH. BULK-SHEAR VALUES STRUGGLE
TO AROUND 20 KTS...SO WIDESPREAD STORM ORGANIZATION IS
UNLIKELY...BUT PULSE STORMS AND AT LEAST SOME LINEAR FEATURES ALONG
THE PRE-FRONTAL TROUGH WILL HAVE THE POTENTIAL TO PRODUCE AN
ISOLATED WIND GUST OR LARGE HAIL STONE THIS AFTN. HIGH-RES HRRR AND
NSSL WRF SUGGEST ONLY ISOLATED STORMS UNTIL THE PRE-FRONTAL TROUGH
THIS EVENING...WHICH WILL BE THE PRIMARY DRIVER OF CONVECTION TODAY.
BY THIS EVENING HOWEVER...WE BEGIN TO LOSE HEATING...AND HAVE CAPPED
POP IN THE HIGH CHC RANGE. HIGHEST PROBABILITY FOR STORMS LOOKS TO
BE ACROSS THE MIDDLE-PART OF THE CWA WHERE THE WESTWARD ADVANCING
SEA BREEZE WILL INTERACT WITH THE EASTWARD MOVING TROUGH.
CONVECTION WILL WANE AFTER DARK...AND LITTLE FANFARE IS EXPECTED
WITH THE ACTUAL FROPA TONIGHT. HOWEVER...A SIGNIFICANT AIRMASS
CHANGE WILL ACCOMPANY THIS FRONT...WITH MUCH DRIER AIR AND LOWS
DROPPING INTO THE MID 60S AT THE COAST...AROUND 60 WELL INLAND.
ALSO NEED TO NOTE A PERSISTENT AREA OF SEA-STRATUS FROM ABOUT NORTH
MYRTLE BEACH TO BALD HEAD ISLAND. SHELF WATERS MUST BE JUST COOL
ENOUGH TO TAP INTO THE IDEALIZED RESIDENCE PARCEL TIMES ENCOUNTERED
BY THE W/SW WINDS IN ORDER TO SATURATE IN THIS AREA. THE COMBINATION
OF THE BACKING WINDS WITHIN THE SEA BREEZE...AS WELL AS SIGNIFICANT
HEATING JUST INLAND...SHOULD BREAK APART THIS STRATUS BY EARLY
AFTN...BUT IT IS UNLIKELY THE NEAR-COAST AREA HERE WILL EXPERIENCE
THE HOT/HUMID/SUNNY DAY GOING ON ELSEWHERE ACROSS THE CWA.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY... SOME VERY PLEASANT WEATHER EXPECTED THROUGH THE
PERIOD. HIGH PRESSURE WELL TO OUR NORTH WILL SHOW LITTLE MOVEMENT
WEDNESDAY WHILE THE TUESDAY NIGHT COLD FRONT STALLS WELL TO OUR
SOUTH. IN BETWEEN THE TWO WE WILL SEE A N TO NE FLOW LOCALLY THAT
WILL BRING SOME MUCH LOWER DEWPOINTS. A MILD LEVEL RIDGE WILL BE
JUST TO OUR WEST ALLOWING FOR DEEP LAYER DRY AIR AND AMPLE SUNSHINE.
ON THURSDAY THE HIGH WILL MOVE CLOSER TO THE REGION KEEPING
TEMPERATURES A BIT BELOW CLIMATOLOGY. A LITTLE MOISTURE RETURN MAY
GET UNDERWAY THURSDAY NIGHT AS THE HIGH MOVES FURTHER TO THE EAST,
MAINLY OVER WESTERN ZONE.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...RETURN FLOW ON FRIDAY AND SATURDAY AS HIGH
PRESSURE SITES OFF THE COAST. THE MID LEVEL RIDGE WILL BE OVERHEAD
HOWEVER PRECLUDING DEEP MOISTURE AND CONFINING IT TO THE LOWER
LEVELS. SO WHILE A STRAY SHOWER OR THUNDERSTORM CANNOT BE RULED
OUT ANY COVERAGE SHOULD BE MINIMAL. OVER THE WEEKEND AND EVEN INTO
MONDAY FOR THAT MATTER THE MID LEVEL RIDGING APPEARS TO RESURGE.
DESPITE THIS THE GFS AND ECMWF BOTH DEPICT AN INCREASE IN
PRECIPITATION COVERAGE. WHILE THE CONTINUED MOISTENING OF THE LOW
LEVELS DOES IN FACT ARGUE FOR THIS THE MID LEVEL DRYNESS PROBABLY
MEANS THAT ITS RATHER SUBTLE. TEMPERATURES MEANWHILE WILL GROW
WARMER EACH DAY AND NIGHT.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY /...
AS OF 18Z...THE SEA BREEZE HAS DEVELOPED WITH PRETTY MUCH A STEADY S-
SSW WIND AROUND 13KT AT THE COASTAL TERMINALS. WINDS AT KFLO/KLBT
ARE SW 8-12KT. TERMINALS ARE VFR...AND THE IFR CIGS JUST NORTH OF
CRE SHOULD REMAIN JUST AWAY FROM THE TERMINAL. CONFIDENCE IS
MODERATE TO HIGH KCRE WILL REMAIN VFR.
A COLD FRONT WILL APPROACH AND MOVE THROUGH THE TERMINALS THIS TAF
PERIOD. IT WILL BE UNSTABLE ENOUGH FOR SHOWERS AND THUNDERSTORMS TO
DEVELOP THIS EVENING. APPEARS THE BEST AREA FOR DEVELOPMENT WILL BE
BETWEEN THE INLAND AND COASTAL TERMINALS WHERE SURFACE WINDS ARE
CONVERGING...AND LATEST HIGH RES GUIDANCE SUGGESTS THIS WILL NOT
EVEN REACH THE COASTAL TERMINALS AS IT STABILIZES BEHIND THE SEA
BREEZE. CONVECTION SHOULD TAPER OFF IN THE EVENING. THE COLD FRONT
WILL MOVE THROUGH DURING OVERNIGHT HOURS. PRECIPITATION WILL DROP
AFTER THE FRONT MOVES THROUGH. VFR WILL CONTINUE INTO THE MORNING
HOURS WITH VFR/NE WINDS AFTER SUNRISE.
EXTENDED OUTLOOK...VFR. SCATTERED SHOWERS FRIDAY.
&&
.MARINE... NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM TUESDAY...HIGH PRESSURE OFFSHORE IS THE DOMINANT
SYNOPTIC FEATURE ACROSS THE WATERS TODAY...DRIVING SW FLOW AND WINDS
OF 10-15 KTS ACROSS THE WATERS. LOCAL ENHANCEMENTS OF UP TO 20
KTS...ALONG WITH A BACKING IN DIRECTION TO THE SOUTH...IS LIKELY
ALONG THE SEA BREEZE THROUGH THE AFTN AS WELL. OTHER THAN SOME
CHOPPY WATERS WITHIN THE NEAR SHORE WATERS THANKS TO THE SEA
BREEZE...WAVE HEIGHTS ARE EXPECTED TO PERSIST AT 2-4 FT WITH A 6-7
SEC PERIOD DOMINANT. A COLD FRONT WILL CROSS THE WATERS LATE TONIGHT
TURNING WINDS TO THE N/NW AT AROUND 15 KTS...AND PUSHING THE HIGHEST
SEAS AWAY FROM THE COAST.
SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM TUESDAY... TUESDAY NIGHT`S FROPA WILL BRING A
NORTHERLY FLOW ON WEDNESDAY. SURFACE HIGH REMAINS UP IN THE GREAT
LAKES SO THE FLOW WILL BE QUITE LIGHT LOCALLY AND SEAS LIKELY JUST
2 TO 3 FT. JUST A SLIGHT VEER WEDNESDAY NIGHT WITH FLOW POSSIBLY
GOING LIGHT AND VARIABLE FOR A TIME. THE HIGH EXTENDS JUST
SLIGHTLY SOUTH ON THURSDAY WHILE PROGRESSING EAST. NE WINDS COULD
INCREASE BY A CATEGORY AND BECOME A LITTLE GUSTY. THE COAST-
PARALLEL FLOW WILL PRECLUDE MUCH BUILDING OF SEAS HOWEVER.
.LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY... THE HIGH TO OUR NORTH PROGRESSES FURTHER
EAST ON FRIDAY LEADING TO MORE VEERING LOCALLY. FRIDAY MAY SEE
ONSHORE/EASTERLY FLOW MOST OF THE DAY WHILE A SOUTHERLY COMPONENT
TRIES TO GET ESTABLISHED MAINLY OVER SOUTHERN ZONES. ON SATURDAY
WE TRANSITION TO A FAIRLY NORMAL RETURN FLOW AROUND HIGH PRESSURE
OFF THE EAST COAST. NOT A BERMUDA HIGH THOUGH WHICH TYPICALLY
BRINGS SOUTHWESTERLY FLOW...THE WEEKEND WILL LIKELY SEE SOUTHEAST
INSTEAD. THERE COULD BE A VERY GRADUAL INCREASE IN WAVE PERIOD AS
A SWELL BECOMES ESTABLISHED.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$ SYNOPSIS...MBB
NEAR TERM...JDW
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...MRR/JDW
MARINE...JDW/MBB
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1049 AM EDT TUE MAY 12 2015
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY AHEAD OF A
COLD FRONT. LESS HUMID AIR ARRIVES ON WEDNESDAY AND SHOULD LAST INTO
THURSDAY AS HIGH PRESSURE MOVES OVERHEAD. THE LATTER PART OF THE
WEEK AND WEEKEND WILL FEATURE A GRADUAL INCREASE IN HUMIDITY AND
THUNDERSTORM CHANCES AS THE HIGH MOVES OFF THE COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM TUESDAY...HOT AND HUMID DAY ONGOING ACROSS THE CWA
EVEN AT THIS EARLY HOUR. AFTER STARTING FROM LOWS AROUND 70...TEMPS
ARE SHOOTING UP QUICKLY THIS MORNING THANKS TO 950MB TEMPS CLOSE TO
22C ON THE 8AM KCHS U/A SOUNDING. HIGH PRESSURE CENTERED WELL
OFFSHORE IS PUMPING RETURN FLOW INTO THE CAROLINAS...WHICH IS
STRENGTHENING WARM ADVECTION IN A PRE-FRONTAL AIRMASS. THE
COMBINATION OF THIS HEAT AND DEWPOINT TEMPS AROUND 70 WILL DRIVE
HEAT INDICES INTO THE MID 90S AWAY FROM THE COAST TODAY...THE MOST
UNCOMFORTABLE DAY OF 2015 SO FAR.
THIS HUMID AIR MASS WILL DRIVE INSTABILITY THIS AFTN...AND
CONVECTION IS ONCE AGAIN EXPECTED ACROSS THE AREA. VERY STEEP LR`S
UP TO 800MB WILL DRIVE RAPID UPDRAFTS...AND SBCAPE IS FORECAST TO
RISE TO AROUND 3000 J/KG...POSSIBLY HIGHER RIGHT ALONG THE SEA
BREEZE. THIS WILL SERVE AS THE FUEL FOR STORMS TODAY...WHICH SHOULD
DEVELOP ALONG THE SEA BREEZE...AND THEN LATER ALONG A PRE-FRONTAL
TROUGH APPROACHING FROM THE WEST. WHILE RESIDUAL BOUNDARIES MAY FIRE
WEAK STORMS...MID LEVEL TEMPS ARE NOT EXCEEDINGLY COOL (-8C AT
500MB) SO WIDESPREAD STRONG UPDRAFTS ARE NOT ANTICIPATED.
STILL...ENOUGH FORCING WILL DRIVE PARCELS UP INTO DECENT HAIL-ZONE
INSTABILITY...AND AN INVERTED-V TYPE SIGNATURE IS PROGGED WELL
INLAND AHEAD OF THE PRE-FRONTAL TROUGH. BULK-SHEAR VALUES STRUGGLE
TO AROUND 20 KTS...SO WIDESPREAD STORM ORGANIZATION IS
UNLIKELY...BUT PULSE STORMS AND AT LEAST SOME LINEAR FEATURES ALONG
THE PRE-FRONTAL TROUGH WILL HAVE THE POTENTIAL TO PRODUCE AN
ISOLATED WIND GUST OR LARGE HAIL STONE THIS AFTN. HIGH-RES HRRR AND
NSSL WRF SUGGEST ONLY ISOLATED STORMS UNTIL THE PRE-FRONTAL TROUGH
THIS EVENING...WHICH WILL BE THE PRIMARY DRIVER OF CONVECTION TODAY.
BY THIS EVENING HOWEVER...WE BEGIN TO LOSE HEATING...AND HAVE CAPPED
POP IN THE HIGH CHC RANGE. HIGHEST PROBABILITY FOR STORMS LOOKS TO
BE ACROSS THE MIDDLE-PART OF THE CWA WHERE THE WESTWARD ADVANCING
SEA BREEZE WILL INTERACT WITH THE EASTWARD MOVING TROUGH.
CONVECTION WILL WANE AFTER DARK...AND LITTLE FANFARE IS EXPECTED
WITH THE ACTUAL FROPA TONIGHT. HOWEVER...A SIGNIFICANT AIRMASS
CHANGE WILL ACCOMPANY THIS FRONT...WITH MUCH DRIER AIR AND LOWS
DROPPING INTO THE MID 60S AT THE COAST...AROUND 60 WELL INLAND.
ALSO NEED TO NOTE A PERSISTENT AREA OF SEA-STRATUS FROM ABOUT NORTH
MYRTLE BEACH TO BALD HEAD ISLAND. SHELF WATERS MUST BE JUST COOL
ENOUGH TO TAP INTO THE IDEALIZED RESIDENCE PARCEL TIMES ENCOUNTERED
BY THE W/SW WINDS IN ORDER TO SATURATE IN THIS AREA. THE COMBINATION
OF THE BACKING WINDS WITHIN THE SEA BREEZE...AS WELL AS SIGNIFICANT
HEATING JUST INLAND...SHOULD BREAK APART THIS STRATUS BY EARLY
AFTN...BUT IT IS UNLIKELY THE NEAR-COAST AREA HERE WILL EXPERIENCE
THE HOT/HUMID/SUNNY DAY GOING ON ELSEWHERE ACROSS THE CWA.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY... SOME VERY PLEASANT WEATHER EXPECTED THROUGH THE
PERIOD. HIGH PRESSURE WELL TO OUR NORTH WILL SHOW LITTLE MOVEMENT
WEDNESDAY WHILE THE TUESDAY NIGHT COLD FRONT STALLS WELL TO OUR
SOUTH. IN BETWEEN THE TWO WE WILL SEE A N TO NE FLOW LOCALLY THAT
WILL BRING SOME MUCH LOWER DEWPOINTS. A MILD LEVEL RIDGE WILL BE
JUST TO OUR WEST ALLOWING FOR DEEP LAYER DRY AIR AND AMPLE SUNSHINE.
ON THURSDAY THE HIGH WILL MOVE CLOSER TO THE REGION KEEPING
TEMPERATURES A BIT BELOW CLIMATOLOGY. A LITTLE MOISTURE RETURN MAY
GET UNDERWAY THURSDAY NIGHT AS THE HIGH MOVES FURTHER TO THE EAST,
MAINLY OVER WESTERN ZONE.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...RETURN FLOW ON FRIDAY AND SATURDAY AS HIGH
PRESSURE SITES OFF THE COAST. THE MID LEVEL RIDGE WILL BE OVERHEAD
HOWEVER PRECLUDING DEEP MOISTURE AND CONFINING IT TO THE LOWER
LEVELS. SO WHILE A STRAY SHOWER OR THUNDERSTORM CANNOT BE RULED
OUT ANY COVERAGE SHOULD BE MINIMAL. OVER THE WEEKEND AND EVEN INTO
MONDAY FOR THAT MATTER THE MID LEVEL RIDGING APPEARS TO RESURGE.
DESPITE THIS THE GFS AND ECMWF BOTH DEPICT AN INCREASE IN
PRECIPITATION COVERAGE. WHILE THE CONTINUED MOISTENING OF THE LOW
LEVELS DOES IN FACT ARGUE FOR THIS THE MID LEVEL DRYNESS PROBABLY
MEANS THAT ITS RATHER SUBTLE. TEMPERATURES MEANWHILE WILL GROW
WARMER EACH DAY AND NIGHT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 3 AM TUESDAY...RETURN FLOW ON FRIDAY AND SATURDAY AS HIGH
PRESSURE SITES OFF THE COAST. THE MID LEVEL RIDGE WILL BE OVERHEAD
HOWEVER PRECLUDING DEEP MOISTURE AND CONFINING IT TO THE LOWER
LEVELS. SO WHILE A STRAY SHOWER OR THUNDERSTORM CANNOT BE RULED
OUT ANY COVERAGE SHOULD BE MINIMAL. OVER THE WEEKEND AND EVEN INTO
MONDAY FOR THAT MATTER THE MID LEVEL RIDGING APPEARS TO RESURGE.
DESPITE THIS THE GFS AND ECMWF BOTH DEPICT AN INCREASE IN
PRECIPITATION COVERAGE. WHILE THE CONTINUED MOISTENING OF THE LOW
LEVELS DOES IN FACT ARGUE FOR THIS THE MID LEVEL DRYNESS PROBABLY
MEANS THAT ITS RATHER SUBTLE. TEMPERATURES MEANWHILE WILL GROW
WARMER EACH DAY AND NIGHT.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 12Z...MID/HIGH CLOUDS ARE DECREASING FROM NW-SE WITH PATCHY
IFR/MVFR CLOUDS MOVING SW-NE. AT KFLO IFR CIGS ARE OCCURRING. AT
KCRE IFR/LIFR MARINE STRATUS IS OCCURRING AND MOVING NNE AND
LIFTING INTO A MVFR LAYER AT KILM. WINDS ARE SSW 4-10 KTS.
EXPECT LITTLE CHANGE OVER THE NEXT COUPLE OF HOURS. LOW CIGS WILL
GRADUALLY BECOME VFR MID-LATE MORNING AS HEATING BEGINS. THEN
THERE IS MODERATE TO HIGH CONFIDENCE VFR WILL PERSIST FOR THE
REMAINDER OF THE TAF VALID PERIOD.
A COLD FRONT WILL APPROACH AND MOVE THROUGH THE TERMINALS THIS TAF
PERIOD. WINDS WILL INCREASE THIS MORNING WITH GUSTS TO AROUND 20KT.
IT WILL BE UNSTABLE ENOUGH FOR SHOWERS AND THUNDERSTORMS TO DEVELOP.
APPEARS MOST WILL DEVELOP BETWEEN THE INLAND AND COASTAL TERMINALS.
WILL INDICATE VCSH IN TAFS AND AMEND LATER IF NECESSARY. CONVECTION
SHOULD TAPER OFF IN THE EVENING. THE COLD FRONT WILL MOVE THROUGH
DURING THE LATE EVENING AND OVERNIGHT HOURS.
EXTENDED OUTLOOK...VFR. SCATTERED SHOWERS FRIDAY.
&&
.MARINE... NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 AM TUESDAY...HIGH PRESSURE OFFSHORE IS THE DOMINANT
SYNOPTIC FEATURE ACROSS THE WATERS TODAY...DRIVING SW FLOW AND WINDS
OF 10-15 KTS ACROSS THE WATERS. LOCAL ENHANCEMENTS OF UP TO 20
KTS...ALONG WITH A BACKING IN DIRECTION TO THE SOUTH...IS LIKELY
ALONG THE SEA BREEZE THROUGH THE AFTN AS WELL. OTHER THAN SOME
CHOPPY WATERS WITHIN THE NEAR SHORE WATERS THANKS TO THE SEA
BREEZE...WAVE HEIGHTS ARE EXPECTED TO PERSIST AT 2-4 FT WITH A 6-7
SEC PERIOD DOMINANT. A COLD FRONT WILL CROSS THE WATERS LATE TONIGHT
TURNING WINDS TO THE N/NW AT AROUND 15 KTS...AND PUSHING THE HIGHEST
SEAS AWAY FROM THE COAST.
SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM TUESDAY... TUESDAY NIGHT`S FROPA WILL BRING A
NORTHERLY FLOW ON WEDNESDAY. SURFACE HIGH REMAINS UP IN THE GREAT
LAKES SO THE FLOW WILL BE QUITE LIGHT LOCALLY AND SEAS LIKELY JUST
2 TO 3 FT. JUST A SLIGHT VEER WEDNESDAY NIGHT WITH FLOW POSSIBLY
GOING LIGHT AND VARIABLE FOR A TIME. THE HIGH EXTENDS JUST
SLIGHTLY SOUTH ON THURSDAY WHILE PROGRESSING EAST. NE WINDS COULD
INCREASE BY A CATEGORY AND BECOME A LITTLE GUSTY. THE COAST-
PARALLEL FLOW WILL PRECLUDE MUCH BUILDING OF SEAS HOWEVER.
.LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY... THE HIGH TO OUR NORTH PROGRESSES FURTHER
EAST ON FRIDAY LEADING TO MORE VEERING LOCALLY. FRIDAY MAY SEE
ONSHORE/EASTERLY FLOW MOST OF THE DAY WHILE A SOUTHERLY COMPONENT
TRIES TO GET ESTABLISHED MAINLY OVER SOUTHERN ZONES. ON SATURDAY
WE TRANSITION TO A FAIRLY NORMAL RETURN FLOW AROUND HIGH PRESSURE
OFF THE EAST COAST. NOT A BERMUDA HIGH THOUGH WHICH TYPICALLY
BRINGS SOUTHWESTERLY FLOW...THE WEEKEND WILL LIKELY SEE SOUTHEAST
INSTEAD. THERE COULD BE A VERY GRADUAL INCREASE IN WAVE PERIOD AS
A SWELL BECOMES ESTABLISHED.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$ SYNOPSIS...MBB
NEAR TERM...JDW
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...MRR
MARINE...JDW/MBB
AREA FORECAST DISCUSSION
NWS NORMAN OK
856 PM CDT WED MAY 13 2015
.UPDATE...
MADE SOME ADJUSTMENTS TO THE PRECIP CHANCES THIS EVENING BASED ON
LATEST RADAR TRENDS. THOUGHT ABOUT CANCELLING THE FLASH FLOOD
WATCH... HOWEVER SOME OF THE HIGH RES MODELS KEEP THE CONVECTION
IN SOUTHWEST MOVING ACROSS THE AREA OVERNIGHT. WITH ANTECEDENT
CONDITIONS WOULD NOT TAKE MUCH ADDITIONAL RAINFALL TO CAUSE
ADDITIONAL FLOODING. THEREFORE WILL KEEP WATCH GOING FOR NOW.
OTHERWISE... NOT OTHER CHANGES AT THIS POINT.
&&
.PREV DISCUSSION... /ISSUED 615 PM CDT WED MAY 13 2015/
AVIATION...
0Z TAFS... IFR/LIFR CEILINGS WILL CONT THIS EVENING. CEILINGSWILL
LIKELY IMPROVE THURSDAY WITH EVERYONE EVENTUALLY AT MVFR/VFR
LEVELS. RAIN... HEAVY AT TIMES WILL CONTINUE TO MOVE ACROSS THE
REGION TONIGHT... GRADUALLY ENDING FROM WEST TO EAST. HOWEVER SOME
LOWERED VISIBILITIES WILL BE POSSIBLE THROUGH THU MORNING.
THUNDERSTORMS WILL ALSO BE POSSIBLE THIS EVENING.
PREV DISCUSSION... /ISSUED 412 PM CDT WED MAY 13 2015/
DISCUSSION...
PRIMARY PRECIPITATION SHIELD CONTINUES TO PIVOT EAST THROUGH
CENTRAL AND EASTERN PORTIONS OF THE COUNTY WARNING AREA...
ALTHOUGH CONVECTION IS REDEVELOPING IN THE TEXAS PANHANDLE AND
WEST TEXAS WHICH MAY MOVE INTO WESTERN PORTIONS OF THE AREA THIS
AFTERNOON AND EVENING AGAIN. HRRR AND OUNWRF SHOW THAT THIS MAY
PERSIST FOR A WHILE THIS EVENING IN WESTERN OKLAHOMA/NORTH TEXAS
BUT LIMITED INSTABILITY SHOULD PREVENT STORMS WIDESPREAD STORMS.
OVERALL... STILL EXPECT GENERAL DECREASE IN PRECIPITATION FROM
WEST TO EAST OVERNIGHT AND EARLY TOMORROW MORNING AS SHORTWAVE
MOVES NORTHEAST PAST THE AREA. FLASH FLOOD WATCH STILL LOOKS GOOD
AS THE MODERATE RAINFALL CAN STILL CAUSE FLOODING ISSUES BECAUSE
OF THE HEAVY RECENT RAINFALL.
STORMS EXPECTED AGAIN THURSDAY NIGHT INTO FRIDAY WITH MOISTURE
INCREASE AND PERHAPS A WEAK SHORTWAVE MOVING THROUGH THE AREA. THE
PRIMARY UPPER TROUGH APPROACHES AND INCREASES POPS SIGNIFICANTLY
FRIDAY NIGHT AND SATURDAY. DECENT SIGNAL OF A COMPLEX DEVELOPING
WEST AND MOVING INTO THE AREA SATURDAY MORNING WITH REDEVELOPMENT
EXPECTED AGAIN ON SATURDAY. THERE ARE STILL SOME QUESTIONS ON THE
EXPECTED EVOLUTION ON SATURDAY... BUT STILL WILL BE LOOKING AT THE
SEVERE WEATHER POTENTIAL FOR SATURDAY AS WE GET CLOSER.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 60 80 65 79 / 50 20 30 40
HOBART OK 58 80 62 81 / 70 10 40 30
WICHITA FALLS TX 61 82 65 82 / 70 10 40 40
GAGE OK 55 83 60 82 / 40 10 30 20
PONCA CITY OK 58 80 65 80 / 90 30 20 30
DURANT OK 63 81 66 79 / 60 40 30 50
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH UNTIL 7 AM CDT THURSDAY FOR OKZ007-008-012-013-
017>020-022>048-050>052.
TX...FLASH FLOOD WATCH UNTIL 7 AM CDT THURSDAY FOR TXZ083>090.
&&
$$
30/25
AREA FORECAST DISCUSSION
NWS NORMAN OK
615 PM CDT WED MAY 13 2015
.AVIATION...
0Z TAFS... IFR/LIFR CEILINGS WILL CONT THIS EVENING. CEILINGSWILL
LIKELY IMPROVE THURSDAY WITH EVERYONE EVENTUALLY AT MVFR/VFR
LEVELS. RAIN... HEAVY AT TIMES WILL CONTINUE TO MOVE ACROSS THE
REGION TONIGHT... GRADUALLY ENDING FROM WEST TO EAST. HOWEVER SOME
LOWERED VISIBILITIES WILL BE POSSIBLE THROUGH THU MORNING.
THUNDERSTORMS WILL ALSO BE POSSIBLE THIS EVENING.
&&
.PREV DISCUSSION... /ISSUED 412 PM CDT WED MAY 13 2015/
DISCUSSION...
PRIMARY PRECIPITATION SHIELD CONTINUES TO PIVOT EAST THROUGH
CENTRAL AND EASTERN PORTIONS OF THE COUNTY WARNING AREA...
ALTHOUGH CONVECTION IS REDEVELOPING IN THE TEXAS PANHANDLE AND
WEST TEXAS WHICH MAY MOVE INTO WESTERN PORTIONS OF THE AREA THIS
AFTERNOON AND EVENING AGAIN. HRRR AND OUNWRF SHOW THAT THIS MAY
PERSIST FOR A WHILE THIS EVENING IN WESTERN OKLAHOMA/NORTH TEXAS
BUT LIMITED INSTABILITY SHOULD PREVENT STORMS WIDESPREAD STORMS.
OVERALL... STILL EXPECT GENERAL DECREASE IN PRECIPITATION FROM
WEST TO EAST OVERNIGHT AND EARLY TOMORROW MORNING AS SHORTWAVE
MOVES NORTHEAST PAST THE AREA. FLASH FLOOD WATCH STILL LOOKS GOOD
AS THE MODERATE RAINFALL CAN STILL CAUSE FLOODING ISSUES BECAUSE
OF THE HEAVY RECENT RAINFALL.
STORMS EXPECTED AGAIN THURSDAY NIGHT INTO FRIDAY WITH MOISTURE
INCREASE AND PERHAPS A WEAK SHORTWAVE MOVING THROUGH THE AREA. THE
PRIMARY UPPER TROUGH APPROACHES AND INCREASES POPS SIGNIFICANTLY
FRIDAY NIGHT AND SATURDAY. DECENT SIGNAL OF A COMPLEX DEVELOPING
WEST AND MOVING INTO THE AREA SATURDAY MORNING WITH REDEVELOPMENT
EXPECTED AGAIN ON SATURDAY. THERE ARE STILL SOME QUESTIONS ON THE
EXPECTED EVOLUTION ON SATURDAY... BUT STILL WILL BE LOOKING AT THE
SEVERE WEATHER POTENTIAL FOR SATURDAY AS WE GET CLOSER.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 60 80 65 79 / 80 20 30 40
HOBART OK 58 80 62 81 / 50 10 40 30
WICHITA FALLS TX 61 82 65 82 / 50 10 40 40
GAGE OK 55 83 60 82 / 60 10 30 20
PONCA CITY OK 58 80 65 80 / 90 30 20 30
DURANT OK 63 81 66 79 / 80 40 30 50
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH THROUGH THURSDAY MORNING FOR OKZ007-008-012-
013-017>020-022>048-050>052.
TX...FLASH FLOOD WATCH THROUGH THURSDAY MORNING FOR TXZ083>090.
&&
$$
30/25/25
AREA FORECAST DISCUSSION
NWS NORMAN OK
1248 PM CDT TUE MAY 12 2015
.AVIATION...
18Z TAFS...VFR CONDITIONS EXPECTED MUCH OF THE TAF PERIOD. FROM
06Z THROUGH 12Z WED...LOW LEVEL MOISTURE WILL INCREASE...RESULTING
MVFR/IFR CIGS SPREADING FROM SW TO NE ACROSS THE REGION...ALONG
WITH LIGHT TO MODERATE RAINFALL. RAIN MAY BECOME HEAVY AT TIMES
DURING THE DAY WED...WITH VSBYS LESS THAN 2 MILES...BUT CONFIDENCE
IN THESE VSBYS IS TOO LOW TO MENTION IN TAFS. FOR NOW WILL GO WITH
PREVAILING -RA AT SOUTHWESTERN TERMINALS...WHERE CONFIDENCE IN
RAIN IS HIGHER.
&&
.PREV DISCUSSION... /ISSUED 1100 AM CDT TUE MAY 12 2015/
UPDATE...
ADJUSTMENTS TO CLOUD COVER AND TEMPERATURES.
DISCUSSION...
ALTHOUGH MID-HIGH CLOUDS WILL THIN SOMEWHAT FROM WEST TO EAST
THROUGH THE AFTERNOON...MOST AREAS OUTSIDE OF FAR NORTH/WEST
OKLAHOMA WILL STAY MOSTLY CLOUDY TODAY AND WILL KEEP TEMPS FROM
GETTING TOO WARM. INCREASED CLOUD COVER AND LOWERED HIGHS A FEW
DEGREES NEAR AND SOUTH OF OKC.
A FEW SPRINKLES MAY MOVE INTO WESTERN NORTH TEXAS THIS AFTERNOON
BUT MAIN RAIN EVENT STILL APPEARS TO COMMENCE AFTER MIDNIGHT
TONIGHT AND MAINLY DURING THE DAY TOMORROW. FLASH FLOOD WATCH WILL
BE CONTINUED FOR LATE TONIGHT AND TOMORROW. LATEST RUN OF MODELS
LOOKS FAVORABLE FOR HEAVIER RAIN AXIS TO BE FARTHER WEST...SOME OF
WHICH WILL BE JUST OUTSIDE OF CURRENT WATCH. HOWEVER...AREAS WEST
OF THE FLASH FLOOD WATCH CAN TAKE MUCH MORE RAIN THAN THE RAIN
SOAKED CENTRAL/SOUTHEAST OKLAHOMA. WE WILL TAKE A CLOSER LOOK TO
EXPANDING THE WATCH BUT IT WILL NOT BE DONE WITH THIS UPDATE.
ALTHOUGH SEVERE WEATHER DOES LOOK POSSIBLE FRIDAY...STILL APPEARS
THAT SATURDAY COULD BE THE PRIMARY IMPACT DAY FOR SEVERE WEATHER.
PREV DISCUSSION... /ISSUED 615 AM CDT TUE MAY 12 2015/
AVIATION...
12Z TAFS...THIN BAND OF SHOWERS AND EMBEDDED STORMS ACROSS CENTRAL
AND WEST TEXAS IS EXPECTED TO REMAIN SOUTH OF TAF SITES
THROUGH THE DAY. OTHERWISE...VFR CONDITIONS ARE EXPECTED THROUGH
6Z...BEFORE CEILINGS LOWER ACROSS WESTERN NORTH TEXAS AND
SOUTHWEST OKLAHOMA AS PRECIPITATION DEVELOPS.
PREV DISCUSSION... /ISSUED 325 AM CDT TUE MAY 12 2015/
DISCUSSION...
EAST TO SOUTHEAST WINDS WILL DEVELOP TODAY AS SURFACE HIGH
PRESSURE OVER KANSAS BUILDS EAST. MEANWHILE...CONVECTION ALONG
THE EAST TEXAS COAST WILL DELAY THE RETURN OF DEEP MOISTURE
NORTHWARD. SCATTERED SHOWERS AND A FEW STORMS HAVE FORMED WITHIN
AN AREA OF MID-LEVEL MOISTURE RETURN OVER CENTRAL AND WEST TEXAS.
THE HRRR SORTA HAS A HANDLE ON THIS AND GRADUALLY WEAKENS IT
DURING THE MORNING...WHILE THE NAM12 IS MORE AGGRESSIVE IN
DEVELOPING CONVECTION IN WESTERN NORTH TEXAS. FOR NOW WILL KEEP
IN CHANCE POPS FOR OUR TEXAS COUNTIES.
ANOTHER HEAVY RAIN EVENT SEEMS LIKELY LATE TUESDAY NIGHT INTO
WEDNESDAY. MODELS ARE SIMILAR IN TRACKING A PROGRESSIVE TROUGH
ACROSS THE SOUTHWESTERN STATES TONIGHT AND THEN OVER WEST TEXAS
AND OKLAHOMA WEDNESDAY INTO EARLY THURSDAY. DEEP MOISTURE IN PLACE
OVER SOUTH TEXAS WILL BE TRANSPORTED NORTHWARD TONIGHT INTO
WEDNESDAY IN ADVANCE OF THE TROUGH. THE BEST COMBINATION OF UPPER
AND LOW LEVEL JET FEATURES...SHOULD FOCUS THE HEAVIEST RAIN OVER
WESTERN NORTH TEXAS AND SOUTHWEST OKLAHOMA EARLY WEDNESDAY...WITH
A GRADUALLY SHIFT NORTH AND EAST DURING THE AFTERNOON AND NIGHT.
WIDESPREAD 2 INCH RAIN AMOUNTS ARE LIKELY WITH 3 TO 4 INCH TOTALS
POSSIBLE. WITH RECENT HEAVY RAIN OVER THE SOUTHERN HALF OF
OKLAHOMA AND NORTH TEXAS...FLOODING WILL AGAIN BE A CONCERN.
BRIEF SHORTWAVE RIDGING ON THURSDAY WILL KEEP RAIN CHANCES
LOW...BUT ANOTHER TROUGH WILL BEGIN TO SHIFT EASTWARD FRIDAY INTO
THE WEEKEND. BETTER INSTABILITY IS EXPECTED TO DEVELOP AHEAD OF
THIS SYSTEM WHICH WILL RESULT IN AN INCREASE IN SEVERE WEATHER
CHANCES FRIDAY INTO SATURDAY. ANOTHER FRONT IS EXPECTED TO PUSH
ACROSS THE SOUTHERN PLAINS SUNDAY INTO MONDAY WHICH WILL BRING
ANOTHER PERIOD OF DRY WEATHER.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 56 67 62 79 / 30 100 100 30
HOBART OK 56 67 61 80 / 40 100 70 20
WICHITA FALLS TX 59 70 64 82 / 60 100 70 30
GAGE OK 53 66 56 81 / 20 80 60 10
PONCA CITY OK 53 66 59 79 / 10 70 100 50
DURANT OK 59 71 64 80 / 40 80 70 50
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
OKZ007-008-012-013-017>020-022>048-050>052.
TX...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
TXZ083>090.
&&
$$
11/84
AREA FORECAST DISCUSSION
NWS NORMAN OK
1100 AM CDT TUE MAY 12 2015
.UPDATE...
ADJUSTMENTS TO CLOUD COVER AND TEMPERATURES.
&&
.DISCUSSION...
ALTHOUGH MID-HIGH CLOUDS WILL THIN SOMEWHAT FROM WEST TO EAST
THROUGH THE AFTERNOON...MOST AREAS OUTSIDE OF FAR NORTH/WEST
OKLAHOMA WILL STAY MOSTLY CLOUDY TODAY AND WILL KEEP TEMPS FROM
GETTING TOO WARM. INCREASED CLOUD COVER AND LOWERED HIGHS A FEW
DEGREES NEAR AND SOUTH OF OKC.
A FEW SPRINKLES MAY MOVE INTO WESTERN NORTH TEXAS THIS AFTERNOON
BUT MAIN RAIN EVENT STILL APPEARS TO COMMENCE AFTER MIDNIGHT
TONIGHT AND MAINLY DURING THE DAY TOMORROW. FLASH FLOOD WATCH WILL
BE CONTINUED FOR LATE TONIGHT AND TOMORROW. LATEST RUN OF MODELS
LOOKS FAVORABLE FOR HEAVIER RAIN AXIS TO BE FARTHER WEST...SOME OF
WHICH WILL BE JUST OUTSIDE OF CURRENT WATCH. HOWEVER...AREAS WEST
OF THE FLASH FLOOD WATCH CAN TAKE MUCH MORE RAIN THAN THE RAIN
SOAKED CENTRAL/SOUTHEAST OKLAHOMA. WE WILL TAKE A CLOSER LOOK TO
EXPANDING THE WATCH BUT IT WILL NOT BE DONE WITH THIS UPDATE.
ALTHOUGH SEVERE WEATHER DOES LOOK POSSIBLE FRIDAY...STILL APPEARS
THAT SATURDAY COULD BE THE PRIMARY IMPACT DAY FOR SEVERE WEATHER.
&&
.PREV DISCUSSION... /ISSUED 615 AM CDT TUE MAY 12 2015/
AVIATION...
12Z TAFS...THIN BAND OF SHOWERS AND EMBEDDED STORMS ACROSS CENTRAL
AND WEST TEXAS IS EXPECTED TO REMAIN SOUTH OF TAF SITES
THROUGH THE DAY. OTHERWISE...VFR CONDITIONS ARE EXPECTED THROUGH
6Z...BEFORE CEILINGS LOWER ACROSS WESTERN NORTH TEXAS AND
SOUTHWEST OKLAHOMA AS PRECIPITATION DEVELOPS.
PREV DISCUSSION... /ISSUED 325 AM CDT TUE MAY 12 2015/
DISCUSSION...
EAST TO SOUTHEAST WINDS WILL DEVELOP TODAY AS SURFACE HIGH
PRESSURE OVER KANSAS BUILDS EAST. MEANWHILE...CONVECTION ALONG
THE EAST TEXAS COAST WILL DELAY THE RETURN OF DEEP MOISTURE
NORTHWARD. SCATTERED SHOWERS AND A FEW STORMS HAVE FORMED WITHIN
AN AREA OF MID-LEVEL MOISTURE RETURN OVER CENTRAL AND WEST TEXAS.
THE HRRR SORTA HAS A HANDLE ON THIS AND GRADUALLY WEAKENS IT
DURING THE MORNING...WHILE THE NAM12 IS MORE AGGRESSIVE IN
DEVELOPING CONVECTION IN WESTERN NORTH TEXAS. FOR NOW WILL KEEP
IN CHANCE POPS FOR OUR TEXAS COUNTIES.
ANOTHER HEAVY RAIN EVENT SEEMS LIKELY LATE TUESDAY NIGHT INTO
WEDNESDAY. MODELS ARE SIMILAR IN TRACKING A PROGRESSIVE TROUGH
ACROSS THE SOUTHWESTERN STATES TONIGHT AND THEN OVER WEST TEXAS
AND OKLAHOMA WEDNESDAY INTO EARLY THURSDAY. DEEP MOISTURE IN PLACE
OVER SOUTH TEXAS WILL BE TRANSPORTED NORTHWARD TONIGHT INTO
WEDNESDAY IN ADVANCE OF THE TROUGH. THE BEST COMBINATION OF UPPER
AND LOW LEVEL JET FEATURES...SHOULD FOCUS THE HEAVIEST RAIN OVER
WESTERN NORTH TEXAS AND SOUTHWEST OKLAHOMA EARLY WEDNESDAY...WITH
A GRADUALLY SHIFT NORTH AND EAST DURING THE AFTERNOON AND NIGHT.
WIDESPREAD 2 INCH RAIN AMOUNTS ARE LIKELY WITH 3 TO 4 INCH TOTALS
POSSIBLE. WITH RECENT HEAVY RAIN OVER THE SOUTHERN HALF OF
OKLAHOMA AND NORTH TEXAS...FLOODING WILL AGAIN BE A CONCERN.
BRIEF SHORTWAVE RIDGING ON THURSDAY WILL KEEP RAIN CHANCES
LOW...BUT ANOTHER TROUGH WILL BEGIN TO SHIFT EASTWARD FRIDAY INTO
THE WEEKEND. BETTER INSTABILITY IS EXPECTED TO DEVELOP AHEAD OF
THIS SYSTEM WHICH WILL RESULT IN AN INCREASE IN SEVERE WEATHER
CHANCES FRIDAY INTO SATURDAY. ANOTHER FRONT IS EXPECTED TO PUSH
ACROSS THE SOUTHERN PLAINS SUNDAY INTO MONDAY WHICH WILL BRING
ANOTHER PERIOD OF DRY WEATHER.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 70 56 67 62 / 0 30 100 100
HOBART OK 71 56 67 61 / 0 40 100 70
WICHITA FALLS TX 71 59 70 64 / 10 60 100 70
GAGE OK 70 53 66 56 / 0 20 80 60
PONCA CITY OK 71 53 66 59 / 0 10 70 100
DURANT OK 72 59 71 64 / 10 40 80 70
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
OKZ007-008-012-013-017>020-022>048-050>052.
TX...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
TXZ083>090.
&&
$$
11/84
AREA FORECAST DISCUSSION
NWS NORMAN OK
615 AM CDT TUE MAY 12 2015
.AVIATION...
12Z TAFS...THIN BAND OF SHOWERS AND EMBEDDED STORMS ACROSS CENTRAL
AND WEST TEXAS IS EXPECTED TO REMAIN SOUTH OF TAF SITES
THROUGH THE DAY. OTHERWISE...VFR CONDITIONS ARE EXPECTED THROUGH
6Z...BEFORE CEILINGS LOWER ACROSS WESTERN NORTH TEXAS AND
SOUTHWEST OKLAHOMA AS PRECIPITATION DEVELOPS.
&&
.PREV DISCUSSION... /ISSUED 325 AM CDT TUE MAY 12 2015/
DISCUSSION...
EAST TO SOUTHEAST WINDS WILL DEVELOP TODAY AS SURFACE HIGH
PRESSURE OVER KANSAS BUILDS EAST. MEANWHILE...CONVECTION ALONG
THE EAST TEXAS COAST WILL DELAY THE RETURN OF DEEP MOISTURE
NORTHWARD. SCATTERED SHOWERS AND A FEW STORMS HAVE FORMED WITHIN
AN AREA OF MID-LEVEL MOISTURE RETURN OVER CENTRAL AND WEST TEXAS.
THE HRRR SORTA HAS A HANDLE ON THIS AND GRADUALLY WEAKENS IT
DURING THE MORNING...WHILE THE NAM12 IS MORE AGGRESSIVE IN
DEVELOPING CONVECTION IN WESTERN NORTH TEXAS. FOR NOW WILL KEEP
IN CHANCE POPS FOR OUR TEXAS COUNTIES.
ANOTHER HEAVY RAIN EVENT SEEMS LIKELY LATE TUESDAY NIGHT INTO
WEDNESDAY. MODELS ARE SIMILAR IN TRACKING A PROGRESSIVE TROUGH
ACROSS THE SOUTHWESTERN STATES TONIGHT AND THEN OVER WEST TEXAS
AND OKLAHOMA WEDNESDAY INTO EARLY THURSDAY. DEEP MOISTURE IN PLACE
OVER SOUTH TEXAS WILL BE TRANSPORTED NORTHWARD TONIGHT INTO
WEDNESDAY IN ADVANCE OF THE TROUGH. THE BEST COMBINATION OF UPPER
AND LOW LEVEL JET FEATURES...SHOULD FOCUS THE HEAVIEST RAIN OVER
WESTERN NORTH TEXAS AND SOUTHWEST OKLAHOMA EARLY WEDNESDAY...WITH
A GRADUALLY SHIFT NORTH AND EAST DURING THE AFTERNOON AND NIGHT.
WIDESPREAD 2 INCH RAIN AMOUNTS ARE LIKELY WITH 3 TO 4 INCH TOTALS
POSSIBLE. WITH RECENT HEAVY RAIN OVER THE SOUTHERN HALF OF
OKLAHOMA AND NORTH TEXAS...FLOODING WILL AGAIN BE A CONCERN.
BRIEF SHORTWAVE RIDGING ON THURSDAY WILL KEEP RAIN CHANCES
LOW...BUT ANOTHER TROUGH WILL BEGIN TO SHIFT EASTWARD FRIDAY INTO
THE WEEKEND. BETTER INSTABILITY IS EXPECTED TO DEVELOP AHEAD OF
THIS SYSTEM WHICH WILL RESULT IN AN INCREASE IN SEVERE WEATHER
CHANCES FRIDAY INTO SATURDAY. ANOTHER FRONT IS EXPECTED TO PUSH
ACROSS THE SOUTHERN PLAINS SUNDAY INTO MONDAY WHICH WILL BRING
ANOTHER PERIOD OF DRY WEATHER.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 71 56 67 62 / 0 30 80 80
HOBART OK 71 56 67 61 / 0 40 90 70
WICHITA FALLS TX 72 59 70 64 / 10 60 90 70
GAGE OK 71 53 66 56 / 0 20 70 60
PONCA CITY OK 72 53 66 59 / 0 10 70 90
DURANT OK 73 59 71 64 / 10 40 80 70
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
OKZ007-008-012-013-017>020-022>048-050>052.
TX...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
TXZ083>090.
&&
$$
AREA FORECAST DISCUSSION
NWS NORMAN OK
325 AM CDT TUE MAY 12 2015
.DISCUSSION...
EAST TO SOUTHEAST WINDS WILL DEVELOP TODAY AS SURFACE HIGH
PRESSURE OVER KANSAS BUILDS EAST. MEANWHILE...CONVECTION ALONG
THE EAST TEXAS COAST WILL DELAY THE RETURN OF DEEP MOISTURE
NORTHWARD. SCATTERED SHOWERS AND A FEW STORMS HAVE FORMED WITHIN
AN AREA OF MID-LEVEL MOISTURE RETURN OVER CENTRAL AND WEST TEXAS.
THE HRRR SORTA HAS A HANDLE ON THIS AND GRADUALLY WEAKENS IT
DURING THE MORNING...WHILE THE NAM12 IS MORE AGGRESSIVE IN
DEVELOPING CONVECTION IN WESTERN NORTH TEXAS. FOR NOW WILL KEEP
IN CHANCE POPS FOR OUR TEXAS COUNTIES.
ANOTHER HEAVY RAIN EVENT SEEMS LIKELY LATE TUESDAY NIGHT INTO
WEDNESDAY. MODELS ARE SIMILAR IN TRACKING A PROGRESSIVE TROUGH
ACROSS THE SOUTHWESTERN STATES TONIGHT AND THEN OVER WEST TEXAS
AND OKLAHOMA WEDNESDAY INTO EARLY THURSDAY. DEEP MOISTURE IN PLACE
OVER SOUTH TEXAS WILL BE TRANSPORTED NORTHWARD TONIGHT INTO
WEDNESDAY IN ADVANCE OF THE TROUGH. THE BEST COMBINATION OF UPPER
AND LOW LEVEL JET FEATURES...SHOULD FOCUS THE HEAVIEST RAIN OVER
WESTERN NORTH TEXAS AND SOUTHWEST OKLAHOMA EARLY WEDNESDAY...WITH
A GRADUALLY SHIFT NORTH AND EAST DURING THE AFTERNOON AND NIGHT.
WIDESPREAD 2 INCH RAIN AMOUNTS ARE LIKELY WITH 3 TO 4 INCH TOTALS
POSSIBLE. WITH RECENT HEAVY RAIN OVER THE SOUTHERN HALF OF
OKLAHOMA AND NORTH TEXAS...FLOODING WILL AGAIN BE A CONCERN.
BRIEF SHORTWAVE RIDGING ON THURSDAY WILL KEEP RAIN CHANCES
LOW...BUT ANOTHER TROUGH WILL BEGIN TO SHIFT EASTWARD FRIDAY INTO
THE WEEKEND. BETTER INSTABILITY IS EXPECTED TO DEVELOP AHEAD OF
THIS SYSTEM WHICH WILL RESULT IN AN INCREASE IN SEVERE WEATHER
CHANCES FRIDAY INTO SATURDAY. ANOTHER FRONT IS EXPECTED TO PUSH
ACROSS THE SOUTHERN PLAINS SUNDAY INTO MONDAY WHICH WILL BRING
ANOTHER PERIOD OF DRY WEATHER.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 71 56 67 62 / 0 30 80 80
HOBART OK 71 56 67 61 / 0 40 90 70
WICHITA FALLS TX 72 59 70 64 / 10 60 90 70
GAGE OK 71 53 66 56 / 0 20 70 60
PONCA CITY OK 72 53 66 59 / 0 10 70 90
DURANT OK 73 59 71 64 / 10 40 80 70
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
OKZ007-008-012-013-017>020-022>048-050>052.
TX...FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH THURSDAY MORNING FOR
TXZ083>090.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MEDFORD OR
731 PM PDT WED MAY 13 2015
UPDATED AVIATION
.SHORT TERM...WATER VAPOR IMAGERY THIS AFTERNOON SHOWS A DEEP
LONGWAVE TROUGH OVER THE NORTHEAST PACIFIC WATERS EXTENDING INLAND
THROUGH THE FAR WESTERN CONUS. EMBEDDED IN THIS LARGE TROUGH ARE
SEVERAL WELL- DEFINED SHORTWAVE TROUGHS FROM COASTAL CALIFORNIA
NORTH TROUGH EASTERN WASHINGTON. CLOSER TO HOME...WE`RE DEALING
WITH SHORTWAVE ENERGY MOVING SOUTH TO NORTH OVER NORTHERN
CALIFORNIA...AND THIS WILL COMBINE WITH SOME INSTABILITY OVER THE
FORECAST AREA TO GENERATE SHOWERS AND SOME THUNDERSTORMS THIS
AFTERNOON. LATEST HRRR GUIDANCE HAS HELPED US REFINE AREAS FOR
THUNDERSTORM POTENTIAL...AND WE HAVE SPREAD THE CHANCES ALL THE
WAY INTO THE UMPQUA BASIN LATE THIS AFTERNOON BASED ON THIS
OUTPUT. STORMS WILL TRACK SOUTH- SOUTHEAST TO NORTH-NORTHWEST SO
ANY SHOWERS AND STORMS OVER THE SISKIYOUS AND CASCADES HAVE THE
POTENTIAL TO MOVE OVER THE MEDFORD AREA THIS AFTERNOON/EVENING.
TONIGHT...SHORTWAVE ENERGY WILL BE OVERHEAD AND WILL MAINTAIN THE
CHANCE FOR SHOWERS FOR MOST OF THE CWA. WE HAVE DECIDED TO KEEP
THUNDERSTORMS OUT OF THE FORECAST OVERNIGHT BECAUSE IT DOES NOT
SEEM LIKE INSTABILITY ALOFT IS FAVORABLE ENOUGH TO SUPPORT
NOCTURNAL STORMS.
TOMORROW SHOULD BE THE BEST CHANCE FOR THUNDERSTORMS OVER A WIDE
AREA OF SOUTHERN OREGON AND NORTHERN CALIFORNIA. INSTABILITY
INCREASES SUBTLY THROUGH MUCH OF THE ATMOSPHERIC COLUMN TOMORROW AND
SHORTWAVE ENERGY WILL BE OF MODERATE STRENGTH. GFS40 850MB COMPUTED
LIFTED INDICES ARE ZERO OR SLIGHTLY NEGATIVE AND THIS SUPPORTS A
SLIGHT CHANCE OF THUNDERSTORMS. BULK SHEAR FROM 0-6KM IS HIGHER
TOMORROW SO THERE IS A BETTER CHANCE FOR A FEW STRONG STORMS.
ON FRIDAY...THE UPPER LOW THAT`S THE SOURCE OF ENERGY FOR OUR
SHOWERS WILL PUSH INTO NEVADA AND PRECIPITATION CHANCES WILL BE
FOCUSED EAST OF THE CASCADES. THE LOW PROGRESSION CONTINUES EASTWARD
AND BY SATURDAY THERE IS INCREASED STABILITY AND LITTLE TO NO
SHORTWAVE ACTIVITY...SO WE HAVE REMOVED RAIN CHANCES FOR A GOOD
PORTION OF THE FORECAST AREA. IN SHORT...SATURDAY SHOULD BE THE
DRIEST DAY OF THE WEEK.
.LONG TERM...SUNDAY MAY 17TH THROUGH WEDNESDAY MAY 20TH...NOT
MANY CHANGES MADE TO THE LONG TERM. MODELS ARE STILL IN GOOD
AGREEMENT ON A GENERAL LONG WAVE TROUGH PATTERN REMAINING OVER THE
AREA. THIS LENDS TO HIGH CONFIDENCE THAT UNSETTLED WEATHER WILL
CONTINUE THROUGH THE EXTENDED PERIOD. MODELS SHOW MARGINAL
INSTABILITY DURING THE AFTERNOONS AND EVENINGS THROUGH THIS TIME
FRAME AND IS ENOUGH TO WARRANT AT LEAST A SLIGHT CHANCE OF
THUNDERSTORMS OVER THE CASCADES AND EAST SIDE. TEMPERATURES WILL
REMAIN WITHIN A FEW DEGREES OF NORMAL THROUGH THE EXTENDED AND DAY
TO DAY VARIABILITY WILL BE MINIMAL. MND
&&
.AVIATION...FOR THE 14/00Z TAF CYCLE...SOME THUNDERSTORM
ACTIVITY IN SISKIYOU AND MODOC COUNTY. STORMS ARE EXPECTED TO
SPREAD NORTHWARD AND TRANSITION TO ORDINARY SHOWERS WITHIN THE
NEXT FEW HOURS.
SHOWERS AND MOSTLY CLOUDY TO OVERCAST SKIES WILL CONTINUE THROUGH
TOMORROW EVENING OVER MOST OF AREA, WITH NEARLY ALL TERMINALS LIKELY
TO SEE AT LEAST A SHOWER IN THE VICINITY. CIGS ARE EXPECTED TO DROP
AND REMAIN PRIMARILY MVFR TONIGHT ALONG THE COAST AND IN THE UMPQUA
BASIN...WITH LOCAL AREAS OF IFR AND PARTIAL TERRAIN OBSCURATION.
MVFR CIGS WILL DEVELOP IN OTHER WEST SIDE VALLEYS BY THURSDAY
MORNING. CIGS SHOULD LIFT TO VFR BY THURSDAY AFTERNOON.
CASCADES AND EAST...MOSTLY VFR CIGS WITH AREAS OF TERRAIN
OBSCURATION AND LOCAL AREAS OF MVFR. POSSIBLE ISOLATED THUNDERSTORMS
THURSDAY AFTERNOON.
-MSC
&&
.MARINE...UPDATED 230 PM PDT WEDNESDAY, MAY 13, 2015...WINDS WILL
REMAIN WEAK TONIGHT AND PRIMARILY SOUTHERLY. SCATTERED LIGHT SHOWERS
WILL AFFECT THE WATERS THROUGH THURSDAY AFTERNOON AS AN UPPER LOW
CURRENTLY CENTERED ROUGHLY 400 MILES WEST OF VANCOUVER ISLAND TRACKS
SOUTH/SOUTHEASTWARD. NORTHWESTERLY SWELL ASSOCIATED WITH THIS SYSTEM
WILL CONTINUE BUILDING THIS EVENING INTO THURSDAY, CAUSING MODERATE
SEAS. NORTHERLY WINDS WILL INCREASE THURSDAY EVENING, BUT ARE
EXPECTED TO REMAIN BELOW ADVISORY CRITERIA. WINDS WILL BE STRONGEST
SOUTH OF CAPE BLANCO. SEAS BEGIN DIMINISHING THURSDAY NIGHT, AND
WILL REMAIN RELATIVELY CALM THROUGH THE WEEKEND. WINDS WILL REMAIN
NORTHERLY TO NORTHWESTERLY AND MODERATE THROUGH THE WEEKEND. BOTH
13/12Z GFS AND EC SHOW SIMILAR LOW PRESSURE SYSTEMS THIS WEEKEND
FORMING FAR ENOUGH OFFSHORE TO KEEP WINDS BELOW ADVISORY CRITERIA.
-MSC
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
NSK/BPN/MND/MSC
AREA FORECAST DISCUSSION...UPDATED
NWS MEDFORD OR
729 PM PDT WED MAY 13 2015
UPDATED AVIATION DISCUSSION
.SHORT TERM...WATER VAPOR IMAGERY THIS AFTERNOON SHOWS A DEEP
LONGWAVE TROUGH OVER THE NORTHEAST PACIFIC WATERS EXTENDING INLAND
THROUGH THE FAR WESTERN CONUS. EMBEDDED IN THIS LARGE TROUGH ARE
SEVERAL WELL- DEFINED SHORTWAVE TROUGHS FROM COASTAL CALIFORNIA
NORTH TROUGH EASTERN WASHINGTON. CLOSER TO HOME...WE`RE DEALING
WITH SHORTWAVE ENERGY MOVING SOUTH TO NORTH OVER NORTHERN
CALIFORNIA...AND THIS WILL COMBINE WITH SOME INSTABILITY OVER THE
FORECAST AREA TO GENERATE SHOWERS AND SOME THUNDERSTORMS THIS
AFTERNOON. LATEST HRRR GUIDANCE HAS HELPED US REFINE AREAS FOR
THUNDERSTORM POTENTIAL...AND WE HAVE SPREAD THE CHANCES ALL THE
WAY INTO THE UMPQUA BASIN LATE THIS AFTERNOON BASED ON THIS
OUTPUT. STORMS WILL TRACK SOUTH- SOUTHEAST TO NORTH-NORTHWEST SO
ANY SHOWERS AND STORMS OVER THE SISKIYOUS AND CASCADES HAVE THE
POTENTIAL TO MOVE OVER THE MEDFORD AREA THIS AFTERNOON/EVENING.
TONIGHT...SHORTWAVE ENERGY WILL BE OVERHEAD AND WILL MAINTAIN THE
CHANCE FOR SHOWERS FOR MOST OF THE CWA. WE HAVE DECIDED TO KEEP
THUNDERSTORMS OUT OF THE FORECAST OVERNIGHT BECAUSE IT DOES NOT
SEEM LIKE INSTABILITY ALOFT IS FAVORABLE ENOUGH TO SUPPORT
NOCTURNAL STORMS.
TOMORROW SHOULD BE THE BEST CHANCE FOR THUNDERSTORMS OVER A WIDE
AREA OF SOUTHERN OREGON AND NORTHERN CALIFORNIA. INSTABILITY
INCREASES SUBTLY THROUGH MUCH OF THE ATMOSPHERIC COLUMN TOMORROW AND
SHORTWAVE ENERGY WILL BE OF MODERATE STRENGTH. GFS40 850MB COMPUTED
LIFTED INDICES ARE ZERO OR SLIGHTLY NEGATIVE AND THIS SUPPORTS A
SLIGHT CHANCE OF THUNDERSTORMS. BULK SHEAR FROM 0-6KM IS HIGHER
TOMORROW SO THERE IS A BETTER CHANCE FOR A FEW STRONG STORMS.
ON FRIDAY...THE UPPER LOW THAT`S THE SOURCE OF ENERGY FOR OUR
SHOWERS WILL PUSH INTO NEVADA AND PRECIPITATION CHANCES WILL BE
FOCUSED EAST OF THE CASCADES. THE LOW PROGRESSION CONTINUES EASTWARD
AND BY SATURDAY THERE IS INCREASED STABILITY AND LITTLE TO NO
SHORTWAVE ACTIVITY...SO WE HAVE REMOVED RAIN CHANCES FOR A GOOD
PORTION OF THE FORECAST AREA. IN SHORT...SATURDAY SHOULD BE THE
DRIEST DAY OF THE WEEK.
LONG TERM...SUNDAY MAY 17TH THROUGH WEDNESDAY MAY 20TH...NOT
MANY CHANGES MADE TO THE LONG TERM. MODELS ARE STILL IN GOOD
AGREEMENT ON A GENERAL LONG WAVE TROUGH PATTERN REMAINING OVER THE
AREA. THIS LENDS TO HIGH CONFIDENCE THAT UNSETTLED WEATHER WILL
CONTINUE THROUGH THE EXTENDED PERIOD. MODELS SHOW MARGINAL
INSTABILITY DURING THE AFTERNOONS AND EVENINGS THROUGH THIS TIME
FRAME AND IS ENOUGH TO WARRANT AT LEAST A SLIGHT CHANCE OF
THUNDERSTORMS OVER THE CASCADES AND EAST SIDE. TEMPERATURES WILL
REMAIN WITHIN A FEW DEGREES OF NORMAL THROUGH THE EXTENDED AND DAY
TO DAY VARIABILITY WILL BE MINIMAL. MND
AVIATION...FOR THE 14/00Z TAF CYCLE...FOR THE 14/00Z TAF CYCLE...SOME THUNDERSTORM
ACTIVITY IN SISKIOY AND MODOC COUNTY. STORMS ARE EXPECTED TO SPREAD
NORTHWARD AND TRANSITION TO ORDINARY SHOWERS WITHIN THE NEXT FEW
HOURS.
SHOWERS AND MOSTLY CLOUDY TO OVERCAST SKIES WILL CONTINUE THROUGH
TOMORROW EVENING OVER MOST OF AREA, WITH NEARLY ALL TERMINALS LIKELY
TO SEE AT LEAST A SHOWER IN THE VICINITY. CIGS ARE EXPECTED TO DROP
AND REMAIN PRIMARILY MVFR TONIGHT ALONG THE COAST AND IN THE UMPQUA
BASIN...WITH LOCAL AREAS OF IFR AND PARTIAL TERRAIN OBSCURATION.
MVFR CIGS WILL DEVELOP IN OTHER WEST SIDE VALLEYS BY THURSDAY
MORNING. CIGS SHOULD LIFT TO VFR BY THURSDAY AFTERNOON.
CASCADES AND EAST...MOSTLY VFR CIGS WITH AREAS OF TERRAIN
OBSCURATION AND LOCAL AREAS OF MVFR. POSSIBLE ISOLATED THUNDERSTORMS
THURSDAY AFTERNOON.
-MSC
MARINE...UPDATED 230 PM PDT WEDNESDAY, MAY 13, 2015...WINDS WILL
REMAIN WEAK TONIGHT AND PRIMARILY SOUTHERLY. SCATTERED LIGHT SHOWERS
WILL AFFECT THE WATERS THROUGH THURSDAY AFTERNOON AS AN UPPER LOW
CURRENTLY CENTERED ROUGHLY 400 MILES WEST OF VANCOUVER ISLAND TRACKS
SOUTH/SOUTHEASTWARD. NORTHWESTERLY SWELL ASSOCIATED WITH THIS SYSTEM
WILL CONTINUE BUILDING THIS EVENING INTO THURSDAY, CAUSING MODERATE
SEAS. NORTHERLY WINDS WILL INCREASE THURSDAY EVENING, BUT ARE
EXPECTED TO REMAIN BELOW ADVISORY CRITERIA. WINDS WILL BE STRONGEST
SOUTH OF CAPE BLANCO. SEAS BEGIN DIMINISHING THURSDAY NIGHT, AND
WILL REMAIN RELATIVELY CALM THROUGH THE WEEKEND. WINDS WILL REMAIN
NORTHERLY TO NORTHWESTERLY AND MODERATE THROUGH THE WEEKEND. BOTH
13/12Z GFS AND EC SHOW SIMILAR LOW PRESSURE SYSTEMS THIS WEEKEND
FORMING FAR ENOUGH OFFSHORE TO KEEP WINDS BELOW ADVISORY CRITERIA.
-MSC
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
NSK/BPN/MND/MSC
AREA FORECAST DISCUSSION...UPDATE
NWS PENDLETON OR
351 PM PDT TUE MAY 12 2015
UPDATED FOR AVIATION DISCUSSION
.SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY NIGHT. AN INTENSE AND
STATIONARY LOW PRESSURE SYSTEM OVER THE PACNW WILL CONTINUE TO PUMP
MOISTURE INTO OUR AREA AND COMBINING THIS WITH DAYTIME HEATING WILL
PRODUCE ISOLATED THUNDERSTORMS THIS AFTERNOON AND EVENING. THE TSRA
COULD BECOME STRONG AND PRODUCE GUSTY WINDS AND HAIL WITH THE BEST
CHANCES OF THIS OCCURRING OVER THE EASTERN ZONES THAT INCLUDES IN
AND AROUND THE BLUE/WALLOWA MOUNTAINS AS WELL AS GRANT COUNTY.
ELSEWHERE SHOWERS WILL CONTINUE DEVELOPING ACROSS THE REGION INTO
THIS EVENING. AS THE LOW DRIFTS INTO NE OREGON LATER TONIGHT
MOISTURE WILL RAP AROUND THIS SYSTEM AND INTO THE EASTERN PORTIONS
OF THE AREA AND MODERATE TO HEAVY RAINFALL IS POSSIBLE WITH UP TO AN
INCH IN SOME LOCATIONS. THE LOW AND THE BULK OF THE MOISTURE DRIFT
NORTH WEDNESDAY MORNING WITH DECREASING CHANCES OF PCPN EXPECTED BUT
THE CLOUDS AND SHOWERS WILL PERSIST INTO WEDNESDAY AFTERNOON. A WEAK
DISTURBANCE WILL NEAR CENTRAL OREGON WEDNESDAY AFTERNOON THAT COULD
PRODUCE AN ISOLD TSRA. OTHERWISE THE BEST CHANCES FOR PCPN SHOULD
OCCUR ALONG THE WA/OR CASCADES WEDNESDAY NIGHT AND THURSDAY.
BY THURSDAY ANOTHER LOW PRESSURE SYSTEM WILL TRACK TO OUR SOUTH BUT
SHOWERS FROM THIS SYSTEM WILL MOVE NORTH AND INTO MOST PORTIONS OF
OUR AREA THURSDAY NIGHT. AFTERNOON TEMPERATURES WILL REMAIN COOL
TOMORROW BEFORE WARMER TEMPERATURES CAN BE EXPECTED THURSDAY.
&&
.LONG TERM...FRIDAY THROUGH MONDAY NIGHT...MILD YET UNSETTLED
WEATHER CAN BE EXPECTED FOR THE EXTENDED. A LOW PRESSURE SYSTEM
CENTERED OVER CENTRAL NEVADA WILL CONTINUE TO SPIN UP MOISTURE AND
POSSIBLE THUNDERSTORMS TO THE AREA ON FRIDAY. THIS SYSTEM WILL EXIT
THE AREA FRIDAY NIGHT WITH ANOTHER LOW MOVING TOWARDS THE PACIFIC
COAST ON SATURDAY. THIS LOW IS CURRENTLY FORECAST TO TRACK SOUTH OF
THE CWA TOWARDS THE NORTHERN CALIFORNIA COAST THROUGH THE WEEKEND.
THIS WILL ALLOW FOR MORE MOISTURE AND INSTABILITY TO BE SPUN UP OVER
THE AREA...PROVIDING ANOTHER CHANCE FOR THUNDERSTORMS. THE LOW IS
EXPECTED TO SLOWLY MOVE INLAND AND BE CENTERED OVER THE CA/NV
BOARDER ON MONDAY NIGHT. OVERALL THE AIRMASS SHOULD BE FAIRLY WARM
OVER THE AREA...KEEPING THE TEMPERATURES NEAR TO ABOVE NORMAL.
REASONABLE CLOUD COVER CAN BE EXPECTED AT NIGHT AS WELL...ALLOWING
FOR MILD NIGHTTIME LOWS. WEBER
&&
.AVIATION...00Z TAFS...MVFR CONDITIONS CAN BE EXPECTED OVER THE NEXT
12-18 HOURS...AS A DEFORMATION BAND IS EXPECTED TO SET UP OVER
SOUTHERN WASHINGTON DURING THIS PERIOD. THIS COULD ALLOW FOR
PERIODS OF MODERATE RAIN...WITH CIGS POSSIBLY FALLING TO IFR
CATEGORIES. FOR NOW PROB30 GROUPS COVER THE PERIODS OF CONCERN.
STILL POSSIBLE -TSRA AT KPDT AND KALW FROM 0Z-3Z THIS
AFTERNOON...BUT DUE TO LOWER CONFIDENCE HAVE REMOVED THE TEMPO GROUP
FOR THUNDER AND JUST LEFT SHOWERS. WINDS WILL RANGE FROM 5 TO 15
KTS...WITH GUSTS UP TO 25 KTS. WEBER
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 45 62 45 64 / 90 70 10 30
ALW 48 65 46 69 / 90 80 10 30
PSC 51 70 46 70 / 90 80 10 20
YKM 49 68 43 70 / 80 70 40 20
HRI 49 69 44 70 / 80 70 10 30
ELN 47 66 41 70 / 90 80 40 20
RDM 35 60 36 59 / 50 30 30 50
LGD 43 62 41 64 / 100 70 20 30
GCD 41 63 39 65 / 80 20 20 50
DLS 48 65 46 71 / 60 50 30 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
97/89/89
AREA FORECAST DISCUSSION
NWS PENDLETON OR
225 PM PDT TUE MAY 12 2015
.SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY NIGHT. AN INTENSE AND
STATIONARY LOW PRESSURE SYSTEM OVER THE PACNW WILL CONTINUE TO PUMP
MOISTURE INTO OUR AREA AND COMBINING THIS WITH DAYTIME HEATING WILL
PRODUCE ISOLATED THUNDERSTORMS THIS AFTERNOON AND EVENING. THE TSRA
COULD BECOME STRONG AND PRODUCE GUSTY WINDS AND HAIL WITH THE BEST
CHANCES OF THIS OCCURRING OVER THE EASTERN ZONES THAT INCLUDES IN
AND AROUND THE BLUE/WALLOWA MOUNTAINS AS WELL AS GRANT COUNTY.
ELSEWHERE SHOWERS WILL CONTINUE DEVELOPING ACROSS THE REGION INTO
THIS EVENING. AS THE LOW DRIFTS INTO NE OREGON LATER TONIGHT
MOISTURE WILL RAP AROUND THIS SYSTEM AND INTO THE EASTERN PORTIONS
OF THE AREA AND MODERATE TO HEAVY RAINFALL IS POSSIBLE WITH UP TO AN
INCH IN SOME LOCATIONS. THE LOW AND THE BULK OF THE MOISTURE DRIFT
NORTH WEDNESDAY MORNING WITH DECREASING CHANCES OF PCPN EXPECTED BUT
THE CLOUDS AND SHOWERS WILL PERSIST INTO WEDNESDAY AFTERNOON. A WEAK
DISTURBANCE WILL NEAR CENTRAL OREGON WEDNESDAY AFTERNOON THAT COULD
PRODUCE AN ISOLD TSRA. OTHERWISE THE BEST CHANCES FOR PCPN SHOULD
OCCUR ALONG THE WA/OR CASCADES WEDNESDAY NIGHT AND THURSDAY.
BY THURSDAY ANOTHER LOW PRESSURE SYSTEM WILL TRACK TO OUR SOUTH BUT
SHOWERS FROM THIS SYSTEM WILL MOVE NORTH AND INTO MOST PORTIONS OF
OUR AREA THURSDAY NIGHT. AFTERNOON TEMPERATURES WILL REMAIN COOL
TOMORROW BEFORE WARMER TEMPERATURES CAN BE EXPECTED THURSDAY.
&&
.LONG TERM...FRIDAY THROUGH MONDAY NIGHT...MILD YET UNSETTLED
WEATHER CAN BE EXPECTED FOR THE EXTENDED. A LOW PRESSURE SYSTEM
CENTERED OVER CENTRAL NEVADA WILL CONTINUE TO SPIN UP MOISTURE AND
POSSIBLE THUNDERSTORMS TO THE AREA ON FRIDAY. THIS SYSTEM WILL EXIT
THE AREA FRIDAY NIGHT WITH ANOTHER LOW MOVING TOWARDS THE PACIFIC
COAST ON SATURDAY. THIS LOW IS CURRENTLY FORECAST TO TRACK SOUTH OF
THE CWA TOWARDS THE NORTHERN CALIFORNIA COAST THROUGH THE WEEKEND.
THIS WILL ALLOW FOR MORE MOISTURE AND INSTABILITY TO BE SPUN UP OVER
THE AREA...PROVIDING ANOTHER CHANCE FOR THUNDERSTORMS. THE LOW IS
EXPECTED TO SLOWLY MOVE INLAND AND BE CENTERED OVER THE CA/NV
BOARDER ON MONDAY NIGHT. OVERALL THE AIRMASS SHOULD BE FAIRLY WARM
OVER THE AREA...KEEPING THE TEMPERATURES NEAR TO ABOVE NORMAL.
REASONABLE CLOUD COVER CAN BE EXPECTED AT NIGHT AS WELL...ALLOWING
FOR MILD NIGHTTIME LOWS. WEBER
&&
.AVIATION...PREVIOUS DISCUSSION...18Z TAFS...MVFR-VFR CONDITIONS
OVER THE NEXT 6 HOURS...WITH BETTER CHANCES OF MVFR CONDITIONS OVER
THE 0Z-12Z WEDNESDAY TIME PERIOD. DEFORMATION BAND EXPECTED TO SET
UP OVER SOUTHERN WASHINGTON DURING THIS PERIOD. THIS COULD ALLOW
FOR PERIODS OF MODERATE RAIN...WITH CIGS POSSIBLY FALLING TO IFR
CATEGORIES. FOR NOW PROB30 GROUPS COVER THE PERIODS OF CONCERN.
POSSIBLE -TSRA AT KPDT AND KALW FROM 0Z-3Z THIS AFTERNOON. HAVE
ADDED A TEMPO GROUP TO COVER THE THUNDER. WINDS WILL RANGE FROM 5
TO 15 KTS...WITH GUSTS UP TO 25 KTS. WEBER
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 45 62 45 64 / 90 70 10 30
ALW 48 65 46 69 / 90 80 10 30
PSC 51 70 46 70 / 90 80 10 20
YKM 49 68 43 70 / 80 70 40 20
HRI 49 69 44 70 / 80 70 10 30
ELN 47 66 41 70 / 90 80 40 20
RDM 35 60 36 59 / 50 30 30 50
LGD 43 62 41 64 / 100 70 20 30
GCD 41 63 39 65 / 80 20 20 50
DLS 48 65 46 71 / 60 50 30 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
97/89/89
AREA FORECAST DISCUSSION
NWS PORTLAND
915 PM PDT MON MAY 11 2015
.SYNOPSIS...AN UPPER LOW WILL MOVE INLAND AND ACROSS SOUTHWESTERN
OREGON TONIGHT AND TUESDAY. A BAND OF STRATIFORM RAIN ALONG
THE COLUMBIA RIVER WILL PINWHEEL SOUTH ALONG THE COAST AND RETURN
INLAND ACROSS THE CENTRAL AND SOUTHERN OREGON COAST TUESDAY. THE
UPPER LOW WILL GRADUALLY FILL AS IT DRIFTS NORTHEAST TOWARD EASTERN
WASHINGTON TUESDAY NIGHT AND WEDNESDAY WITH LIGHT SHOWER ACTIVITY
CONTINUING. AT THE SAME TIME...ANOTHER LOW DROPS SOUTH OFF THE
PACIFIC NORTHWEST COAST AND SLOWLY MOVES INTO CALIFORNIA DURING THE
LATTER PART OF THE WEEK AND NEXT WEEKEND.
&&
.UPDATE...UPPER LOW CENTER ROUGHLY OVER THE SOUTHERN OREGON COAST
NEAR PORT ORFORD. THE BULK OF CONVECTION EAST OF THE CASCADES HAS
ENDED WITH A COUPLE STRAY CELLS FIRING AT THIS HOUR. 21Z SREF AND
00Z NAM/GFS RUNS ARE KEEPING THE UPPER LOW CENTER JUST THIS SIDE OF
THE OR/CA BORDER FOR TONIGHT WHICH IS CLOSER TO WHAT PREVIOUS RUNS
OF THE NAM HAD SHOWN. ADDITIONALLY...THE BETTER DYNAMIC LIFT
ASSOCIATED WITH THE DIFFLUENT SE QUADRANT OF THE LOW DEVELOPED ABOUT
75 MILES FURTHER EAST THAN WAS PREVIOUSLY EXPECTED. THUS...A BLEND
OF THE 00Z NAM...AND TO A LESSER EXTENT...THE 12Z ECMWF SEEMS TO BE
A DECENT MIDDLE GROUND WITH REGARD TO HANDLING THE REST OF TONIGHT.
AS SUCH...AM FEELING THE PRIMARY DEFORMATION BAND WILL STAY ALONG
THE COLUMBIA RIVER WITH THE EASTERLY FLOW ALONG THE NORTHERN
PERIPHERY OF THE UPPER CIRCULATION CONTINUING TO STREAM
PRECIPITATION OUT TO SEA ACROSS ASTORIA. OVERNIGHT WILL SEE THE FLOW
AND DEEPER MOISTURE THEN WRAP BACK SOUTH CLOSER TO THE COAST.
THIS STANDS TO LEAVE THE CASCADE WEST SLOPES (NOW IN THE LEE OF THE
SYSTEM) ON THE RELATIVELY DRIER SIDE OF THINGS. THE LEADING EDGE OF
THE WRAP AROUND MOISTURE THEN CURLS BACK INLAND AROUND
NEWPORT/FLORENCE AND PICKS UP A BIT OF UPSLOPE ENHANCEMENT FOR THE
MORNING HOURS TOMORROW. DID NOT HAVE ENOUGH CONFIDENCE THEREAFTER TO
MAKE CHANGES TO THE FORECAST PACKAGE AS WE WILL NEED TO SEE HOW THIS
FIRST PART WORKS OUT. IT SHOULD BE SAID THAT NO ONE MODEL IS REALLY
DOING A STELLAR JOB OF FINDING THE CORRECT MIX OF RAIN PLACEMENT
WITH RAIN INTENSITY LEAVING THIS FORECAST WITH MODERATE CONFIDENCE
AT BEST.
UPDATES WILL BE AVAILABLE SHORTLY. /JBONK
&&
.AVIATION...RAIN AND OCCASIONAL MVFR CIG/VIS ARE SPREADING WEST
AND SOUTH THIS EVENING WITH THE TREND CONTINUING INTO THE LATE
EVENING. EXPECT MORE WIDESPREAD MVFR CONDITIONS TO DEVELOP
THROUGH THE OVERNIGHT AND STICK AROUND MUCH OF TUESDAY WITH RAIN.
WINDS WILL BE VARIABLE THROUGH THE PERIOD AND GENERALLY REMAIN
BELOW 10 KT.
KPDX AND APPROACHES...MVFR CIGS DEVELOPING BY 12Z TUESDAY AND
STAYING THROUGH TUESDAY. OCCASIONAL MVFR VIS WITH RAIN. BOWEN
&&
.MARINE...HIGH PRESSURE OVER THE NE PACIFIC IS KEEPING CONDITIONS
FAIRLY BENIGN. SEAS SHOULD REMAIN AROUND 5 TO 7 FT THROUGH
TUESDAY WITH NORTHWESTERLY WINDS STAYING BELOW 20 KT. SEAS WILL BE
CHOPPY DUE TO SHORT PERIODS AROUND 8 SECONDS. MADE ONLY MINOR
TWEAKS TO THE FORECAST FOR THE EVENING UPDATE. BOWEN
A WEAK LOW PRESSURE SYSTEM MOVES THROUGH ON WEDNESDAY...BUILDING
SEAS TO AROUND 8 FT...BUT WINDS EXPECTED TO REMAIN BELOW 20 KT.
SEAS FALL BACK DOWN TO 5 TO 6 FT BY THE END OF THIS WEEK WITH THE
RETURN OF NORTHWESTERLY WINDS AS HIGH PRESSURE BUILDS BACK OVER
THE WATERS. -MCCOY
&&
.PREV DISCUSSION... /ISSUED 215 PM PDT MON MAY 11 2015/
SHORT TERM...TONIGHT THROUGH THURSDAY...EARLY-AFTERNOON WATER VAPOR
LOOP SHOWS AN UPPER LEVEL LOW CENTERED WEST OF KONP AND SINKING TO
THE S. CONSIDERABLE MOISTURE IN WATER VAPOR FOCUSED OVER THE
CASCADES. ALSO LOOKS LIKE A SHORT-WAVE ROTATING INTO SOUTH-CENTRAL
OREGON...WHICH HAS RESULTED IN THUNDERSTORM ACTIVITY IN SWRN LAKE
COUNTY. KRTX DUAL-POL DOPPLER RADAR SHOWS THE BULK OF THE PRECIP
ECHOES ALONG THE CENTRAL AND NORTH OREGON CASCADES INTO ERN CLARK AND
COWLITZ COUNTIES IN SW WA. 12Z MODEL RUNS AGREE THAT THE UPPER LOW
WILL CONTINUE TO DRIFT SOUTH THIS EVENING...THEN MOVE INLAND OVER NW
CALIFORNIA BY 12Z TUE. MODELS ALSO SUGGEST THAT PRECIP WILL BECOME
MORE ENHANCED LATE THIS AFTERNOON DUE TO SE-S MID-LEVEL FLOW.
HOWEVER...MODELS DO NOT SEEM TO AGREE ON QPF. GFS SHOW MUCH MORE
RAINFALL TONIGHT THAN THE NAM OR ECMWF. THE NAM PIVOTS THE DEVELOPING
DEFORMATION BAND FURTHER N THAN THE GLOBAL MODELS. THE 19Z HRRR RUN
HAS THE DEFORMATION BAND DEVELOPING A FEW HOURS LATER THAN THE
EARLIER MORNING RUNS INDICATED...AND SETTLING OVER SRN WA DOWN TO
ABOUT A KTMK-KSLE-MT. HOOD LINE BY 07Z TUE. HIGH CONFIDENCE IN
WETTING RAIN AMOUNTS...ONE-QUARTER INCH OR GREATER...ACROSS PORTIONS
OF THE CWA TONIGHT AND TUE MORNING. LOWER CONFIDENCE ON EXACT
LOCATION OF THE DEFORMATION BAND.
CONVECTIVE CHANCES TODAY DO NOT LOOK ALL THAT IMPRESSIVE. NAM
SOUNDINGS FOR KPDX SHOW AN ISOTHERMAL LAYER THIS AFTERNOON BETWEEN 850
AND 700 MB. MODEL SOUNDING FOR A POINT IN THE CASCADES HAS THE SAME
GENERAL PROFILE...BUT DOES HAVE AN LI NEAR 0C THIS AFTERNOON.
INCREASED POPS IN THE 00-06Z TUE TIME FRAME...ESPECIALLY IN THE
CASCADES AND NORTHERN ZONES. THE DEFORMATION ZONE PERSISTS TUE
MORNING. THE NAM ROTATES IT ACROSS SW WA TO THE N OREGON COAST BY 18Z
TUE...SIMILAR TO THE ECMWF. IT FINALLY BREAKS UP TUE AFTERNOON. THE
MODELS SHOW A DECENT AMOUNT OF CYCLONIC LOW LEVEL ONSHORE FLOW
DEVELOPING BELOW THIS BAND AS WELL. CASCADE MODEL SOUNDINGS SUGGEST A
LIT MORE SUPPORT FOR CONVECTION TUE AFTERNOON. NAM SOUNDING GIVES
200-250 J/KG CAPE 00Z WED...WHILE THE GFS HAS NEAR-ZERO LI VALUES.
THE REMAINS OF THE UPPER LOW LIFT OUT INTO SE WASHINGTON TUE NIGHT
AND INTO NE WA BY WED AFTERNOON. ANY REMAINING DEFORMATION WILL
LINGER OVER THE S WA CASCADES WED MORNING AND HAVE THE HIGHEST POPS
THERE. DECIDED TO INCLUDE A MENTION OF THUNDERSTORMS FOR THE CENTRAL
AND N OREGON CASCADES BEGINNING WED AFTERNOON. MODEL SOUNDINGS SHOW A
DEFINITE CAP AROUND 700 MB WED MORNING...BUT BY 21Z THE CAP IS GONE
WITH CAPE OVER 100 J/KG. AT 00Z THU MODEL CAPE HAS INCREASED TO
NEARLY 300 J/KG WITH LI -1C. THINK THE S WA CASCADES WILL HAVE TOO
MUCH CLOUD COVER AS THE DEFORMATION BAND SLOWLY DRIFTS N. MUCH MORE
IMPRESSIVE CONVECTIVE ENVIRONMENT POSSIBLE THU. PRIMARY UPPER LOW
SETTLES OFF THE N CALIFORNIA COAST THU AFTERNOON...WHICH SETS UP
UNSTABLE SE-S FLOW OVER THE FORECAST AREA. NAM SOUNDING NEAR SANTIAM
PASS HAS NEARLY 550 J/KG CAPE WITH AN LI OF -2C 00Z FRI. GFS EVEN
MORE IMPRESSIVE WITH CONVECTIVE PARAMETERS THU. WEISHAAR
LONG TERM...THURSDAY NIGHT THROUGH SUNDAY...BY THURSDAY NIGHT A
BROAD UPPER LOW PRESSURE WILL CONTINUE A GENERAL TRACK SOUTHWARD
ALONG THE CALIFORNIA COAST. MODEL GUIDANCE THIS AFTERNOON IS COMING
INTO GOOD AGREEMENT WITH THE GENERAL PATTERN AND EXPECT SHOWERS
LINGERING THURSDAY NIGHT AND ALSO ON FRIDAY...WITH THE BEST CHANCES
TOWARDS THE CASCADES. MIGHT ALSO BE ENOUGH INSTABILITY TO GET A FEW
THUNDERSTORMS NEAR THE CASCADES FROM MT HOOD SOUTHWARD ON FRIDAY.
THIS UPPER LOW CONTINUES EASTWARD WITH THE NEXT UPPER LOW PRESSURE
SYSTEM MOVING TOWARDS THE REGION OVER THE WEEKEND...MAINTAINING
ONSHORE FLOW ALOFT AND THE POTENTIAL FOR CONTINUING SHOWERS THIS
WEEKEND. OVERALL...NOT MUCH CHANGE TO THE OVERALL PATTERN THROUGH
THE EXTENDED PERIOD WITH TEMPERATURES NEAR SEASONAL NORMS AND SHOWER
CHANCES CONTINUING. CULLEN
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
INTERACT WITH US VIA SOCIAL MEDIA
WWW.FACEBOOK.COM/NWSPORTLAND
WWW.TWITTER.COM/NWSPORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON
FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS
COMMONLY REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1136 AM EDT TUE MAY 12 2015
.SYNOPSIS...
OUR RECENT STRING OF WARM DAYS AND MILD NIGHTS WILL BE CUT TODAY
AS A STRONG COLD FRONT PUSHES EAST ACROSS THE STATE. COOLER...
DRIER AND WINDY CONDITIONS WILL ARRIVE DURING THE DAYLIGHT HOURS
TODAY...AND LAST THROUGH WEDNESDAY NIGHT. A LARGE AREA OF HIGH
PRESSURE WILL BECOME CENTERED OVER THE STATE WEDNESDAY NIGHT AND
EARLY THURSDAY. AS THE HIGH DRIFTS EAST AND OFF THE MID ATLANTIC
COAST...MILDER CONDITIONS WILL RETURN FOR THURSDAY AND FRIDAY AND
CONTINUE THIS WEEKEND AS ANOTHER UPPER RIDGE BUILDS ACROSS THE
REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD FRONT TRACKING ACROSS CENTRAL PA LATE THIS MORNING...
DELINEATED BY LINE OF SHALLOW CONVECTION. KBFD JUST HAD A PEAK
WIND OF 32 KTS AS THIS BAND MOVED ACROSS...IN LINE WITH PREVIOUS
EXPECTATIONS. HI RES HRRR AND 4KM SPC WRF AND MODEL SOUNDINGS
INDICATE A RIBBON OF A FEW TO SEVERAL HUNDRED J/KG AVAILABLE FOR
SHALLOW CONVECTION TO ACCOMPANY ITS PASSAGE ACROSS MOST OF CENTRAL
PA. HI RES SIMULATIONS DAMPEN CONVECTION OVER THE LOWER SUSQ LATER
TODAY DUE TO INCREASING DOWNSLOPE COMPONENT...BUT WE`LL LIKELY SEE
SOME GUSTY SHOWERS WITH ISOLATED THUNDER FOR MUCH OF THE EARLY
AFTERNOON AS THE FRONT SLIDES EAST. STRONG COLD ADVECTION AND
30-40 KT 850 MB WINDS WILL INCREASINGLY MIX BY THIS AFTERNOON
BEHIND THE FRONT...WITH FREQUENT GUSTS OF 30+ MPH REACHING THE
SFC.
HIGH TEMPS WILL RANGE FROM THE COOLISH M-U60S NW...TO THE LOWER
AND MID 80S IN THE SOUTHEAST /WHICH WILL BE ABOUT 10-12 DEG ABOVE
NORMAL FOR TODAY IN THE GREATER HARRISBURG...YORK...LANCASTER
AREA/.
EXTENSIVE...COLD AIR STRATO CU WILL SPREAD INTO THE WEST THIS
AFTERNOON...BUT BREAK UP AND FLATTEN OUT IN THE LLVL DOWNSLOPE AND
ADIABATIC WARMING/DRYING REGIME ACROSS THE CENTRAL VALLEYS AND
SUSQ REGION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
DEEPENING NW FLOW...WITH SHALLOW COLD AIR AT LLVLS WILL LEAD TO
GENERALLY PARTLY SKIES ACROSS THE SUSQ VALLEY....WITH MOSTLY CLOUD
TO CLOUDY CONDITIONS OVER THE MW MTNS.
THIS CLOUD DISTRIBUTION WILL HELP TO LESSEN THE NORMAL STRONG
NW/SE DIFF IN MIN TEMPS ACROSS THE STATE.
LOWS EARLY TUESDAY WILL BE IN THE UPPER 30S TO LOW 40S WEST...AND
IN THE U40S TO LOWER 50S THROUGHOUT THE SUSQEHANNA VALLEY
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
LATER SHIFTS WILL NEED TO MONITOR THE THREAT FOR FROST OR FREEZE
PRODUCTS WED NIGHT AS TEMPS WILL BE PLUMMETING INTO THE U20S/L30S
INVOF KBFD...AND MID 30S TO AROUND 40F AS YOU HEAD SE FROM THE
I99/RT200 CORRIDOR TWD INTERSTATE 81. LOWS ACROSS THE LOWER SUSQ
VALLEY SHOULD BE AOA 40F EARLY THURSDAY.
A FEW WEAK SYSTEMS CRESTING THE MEAN EASTERN U.S. UPPER RIDGE AND
DROPPING SE FROM THE GLAKES WILL BRING THE CHC OF SOME SHOWERS
FRIDAY AFTERNOON THROUGH SAT.
UPPER RIDGE SHARPENS OVER THE MID ATLANTIC REGION SAT NIGHT INTO
SUNDAY. WASHED OUT FRONT TO THE SOUTH OF THE STATE SAT NIGHT WILL
LIKELY RETURN NORTH AS A WARM FRONT SUNDAY...BRINGING BACK THE CHC
FOR SHOWERS/SCTD TSRA SUNDAY AFTERNOON INTO EARLY NEXT WEEK AHEAD
OF A STRONGER SYSTEM THAT WILL BE GRADUALLY SHEARING OUT AS IT
HEADS NE TWD THE GLAKES REGION.
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
COLD FRONT AND NARROW BAND OF MVFR CIGS/SHRA WITH SFC WND G35
KTS SPREADING ACROSS NORTHERN AND CENTRAL AIRFIELDS. ASSOC DRIER
AIR WILL CAUSE CIGS TO BECOME VFR...EVEN OVR THE W MTNS THIS
AFTERNOON.
WIDESPREAD VFR CONDS EXPECTED FOR THE BALANCE OF THE DAY...AS
DRIER AIR FLOWS IN BEHIND COLD FRONT. MAIN CONCERN LATER TODAY
WILL BE THE GUSTY WEST WINDS...RESULTING FROM TIGHT PRESSURE
GRADIENT SOUTH OF LOW PRES OVR S QUEBEC. MDL SOUNDINGS SUPPORT
GUSTS BTWN 25-30KTS BY THIS AFTN. THE STRONGEST GUSTS WILL
DIMINISH AFTER SUNSET...BUT IT WILL REMAIN BREEZY OVERNIGHT.
OUTLOOK...
WED...NO SIG WX EXPECTED.
THU...EARLY AM FOG POSS NW MTNS.
FRI...PM SHRA/CIG REDUCTIONS POSS...MAINLY NW MTNS.
SAT...SCT PM TSRA IMPACTS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...DEVOIR/LAMBERT
SHORT TERM...LAMBERT
LONG TERM...LAMBERT
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
613 AM EDT TUE MAY 12 2015
.SYNOPSIS...
OUR RECENT STRING OF WARM DAYS AND MILD NIGHTS WILL BE CUT TODAY
AS A STRONG COLD FRONT PUSHES EAST ACROSS THE STATE. COOLER...
DRIER AND WINDY CONDITIONS WILL ARRIVE DURING THE DAYLIGHT HOURS
TODAY...AND LAST THROUGH WEDNESDAY NIGHT. A LARGE AREA OF HIGH
PRESSURE WILL BECOME CENTERED OVER THE STATE WEDNESDAY NIGHT AND
EARLY THURSDAY. AS THE HIGH DRIFTS EAST AND OFF THE MID ATLANTIC
COAST...MILDER CONDITIONS WILL RETURN FOR THURSDAY AND FRIDAY AND
CONTINUE THIS WEEKEND AS ANOTHER UPPER RIDGE BUILDS ACROSS THE
REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SFC-850 MB NORTH/SOUTH THETA-E RIDGE WAS SLIDING INTO THE EASTERN
HALF OF THE STATE AT 09Z...WITH JUST A FEW BRIEF SHOWERS OR
SPRINKLES RACING ENE.
SFC DEWPOINTS DROPPING OFF BY SEVERAL DEG F ACROSS WESTERN
PENN /TO THE WEST OF RT 219/...AND THIS MARKS THE WEAK...INITIAL
COLD FRONT THAT WILL SLIDE ACROSS MUCH OF THE FCST AREA BY 12Z.
COLD FRONT JUST PUSHED THROUGH KTOL OVER THE PAST HOUR...AND
WE/LL HAVE TO CONTENT WITH THIS WEATHER FEATURE DURING THE LATE
MORNING /WEST/ AND AFTERNOON HOURS /EAST/.
WELL DEFINED DRY SLOT WITHIN 50 MILES WITHER SIDE OF THE
FRONT...WILL BE PUSHING OVER THE CWA LATE THIS MORNING /WEST/ AND
DURING THE AFTERNOON /EAST/.
TEMPS WILL CLIMB ONLY ABOUT 5-7 DEG ACROSS THE ALLEGHENIES OF NW
PENN TODAY...WHILE THE CENTRAL AND SE VALLEYS SEE A TEMP INCREASE
OF 13 TO 15F TODAY.
HIGH TEMPS RANGING FROM THE U60S NW...TO THE MID 80S IN THE
SOUTHEAST WILL BE ABOUT 10-12 DEG ABOVE NORMAL FOR TODAY.
EXTENSIVE...COLD AIR STRATO CU WILL SPREAD INTO THE THIS
AFTERNOON...BUT BREAK UP AND FLATTEN OUT IN THE LLVL DOWNSLOPE
AND ADIABATIC WARMING/DRYING REGIME ACROSS THE CENTRAL VALLEYS
AND SUSQ REGION.
IN ADDITION...LATEST MODEL FORECAST SOUNDINGS INDICATE MODERATE
MIXING POTENTIAL WITH MANY AREAS SEEING WIND GUSTS IN THE 30-35
MPH RANGE /OR SLIGHTLY HIGHER/. EXPECT HIGHER TERRAIN OF THE
NORTH AND WEST TO SEE SCT -SHRA...WHILE CENTRAL AND SOUTHEAST
AREAS REMAIN PARTLY SUNNY AND DRY.
HIGHS WILL RANGE FROM JUST 60 TO 65F ACROSS THE NORTHWEST MTNS...TO
THE LOWER 80S THROUGHOUT THE LOWER SUSQ RIVER VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
DEEPENING NW FLOW...WITH SHALLOW COLD AIR AT LLVLS WILL LEAD TO
GENERALLY PARTLY SKIES ACROSS THE SUSQ VALLEY....WITH MOSTLY CLOUD
TO CLOUDY CONDITIONS OVER THE MW MTNS.
THIS CLOUD DISTRIBUTION WILL HELP TO LESSEN THE NORMAL STRONG DIFF
IN MIN TEMPS ACROSS CENTRAL PENN AND THE SUSQ VALLEY.
LOWS EARLY TUESDAY WILL BE IN THE UPPER 30S TO LOW 40S WEST...AND
IN THE U40S TO LOWER 50S THROUGHOUT THE SUSQEHANNA VALLEY
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
LATER SHIFTS WILL NEED TO MONITOR THE THREAT FOR FROST OR FREEZE
PRODUCTS WED NIGHT AS TEMPS WILL BE PLUMMETING INTO THE U20S/L30S
INVOF KBFD...AND MID 30S TO AROUND 40F AS YOU HEAD SE FROM THE
I99/RT200 CORRIDOR TWD INTERSTATE 81. LOWS ACROSS THE LOWER SUSQ
VALLEY SHOULD BE AOA 40F EARLY THURSDAY.
A FEW WEAK SYSTEMS CRESTING THE MEAN EASTERN U.S. UPPER RIDGE AND
DROPPING SE FROM THE GLAKES WILL BRING THE CHC OF SOME SHOWERS
FRIDAY AFTERNOON THROUGH SAT.
UPPER RIDGE SHARPENS OVER THE MID ATLANTIC REGION SAT NIGHT INTO
SUNDAY. WASHED OUT FRONT TO THE SOUTH OF THE STATE SAT NIGHT WILL
LIKELY RETURN NORTH AS A WARM FRONT SUNDAY...BRINGING BACK THE CHC
FOR SHOWERS/SCTD TSRA SUNDAY AFTERNOON INTO EARLY NEXT WEEK AHEAD
OF A STRONGER SYSTEM THAT WILL BE GRADUALLY SHEARING OUT AS IT
HEADS NE TWD THE GLAKES REGION.
&&
.AVIATION /10Z TUESDAY THROUGH SATURDAY/...
RADAR AT 06Z SHOWS ONE LINE OF SHRA/TSRA PUSHING THRU EASTERN PA
AND ANOTHER BATCH OF SHRA ASSOC WITH APPROACHING COLD FRONT OVER
WESTERN PA. FOR MUCH OF CENTRAL PA...NO SIG CIG/VIS REDUCTIONS
ARE EXPECTED EARLY THIS MORNING. THE EXCEPTION COULD BE KBFD AND
KJST...WHERE A BRIEF PERIOD OF IFR CIGS MAY DEVELOP AS PLUME OF
MOIST AIR ALONG COLD FRONT ASCENDS THE W MTNS. MDL RH TIMESECTIONS
AND HRRR OUTPUT SUGGEST THE WINDOW OF OPPORTUNITY FOR IFR CONDS AT
KBFD/KJST WILL BE 09Z-11Z. AFTER 11Z...DRIER AIR WILL ARRIVE ON
WEST WIND...CAUSING IMPROVING CONDS.
WIDESPREAD VFR CONDS EXPECTED AFTER SUNRISE...AS DRIER AIR FLOWS
IN BEHIND COLD FRONT. MAIN CONCERN TODAY WILL BE THE GUSTY WEST
WINDS...RESULTING FROM TIGHT PRESSURE GRADIENT SOUTH OF LOW PRES
OVR S QUEBEC. MDL SOUNDINGS SUPPORT GUSTS BTWN 25-30KTS BY THIS
AFTN. THE STRONGEST GUSTS WILL DIMINISH AFTER SUNSET...BUT IT
WILL REMAIN BREEZY OVERNIGHT.
OUTLOOK...
WED...NO SIG WX EXPECTED.
THU...EARLY AM FOG POSS NW MTNS.
FRI...PM SHRA/CIG REDUCTIONS POSS...MAINLY NW MTNS.
SAT...SCT PM TSRA IMPACTS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...LAMBERT/MARTIN
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
346 AM EDT TUE MAY 12 2015
.SYNOPSIS...
SUMMERTIME WARMTH AND HUMIDITY WILL COME TO AN END TODAY AS A
VIGOROUS UPPER TROF AND ASSOCIATED COLD FRONT CROSSES THE REGION.
COOLER...DRIER AND WINDY CONDITIONS WILL ARRIVE DURING THE
DAYLIGHT HOURS TUESDAY...AND LAST THROUGH WEDNESDAY NIGHT. MILDER
CONDITIONS WILL RETURN FOR THURSDAY AND FRIDAY AND CONTINUE THIS
WEEKEND AS ANOTHER UPPER RIDGE BUILDS ACROSS THE REGION.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
SFC-850 MB NORTH/SOUTH THETA-E RIDGE WAS SLICING RIGHT THROUGH
CENTRAL PENN AT 07Z WITH JUST SOME ISOLATED-SCATTERED SHOWERS
RACING QUCIKLY TO THE ENE.
SFC DEWPOINTS DROPPING OFF BY SEVERAL DEG F ALONG THE PENN/OHIO
BORDER ATTM /MARKING THE WEAK...INITIAL COLD FRONT THAT WILL SLIDE
ACROSS MUCH OF THE FCST AREA BY 12Z.
TEMPS WILL STAY MILD FOR THE REST OF THE NIGHT AND IT WILL FEEL
MUGGY WITH TEMPS AND DEWPOINTS IN THE L-M 60S /EXCEPT U50S INVOF
KBFD/.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
INITIAL CFRONT CLEARS OUR FAR EASTERN COUNTIES DURING THE MID
MORNING HOURS TODAY...FOLLOWED BY WINDY AND DRIER CONDITIONS IN
STORE FOR MOST OF THE REGION. MODEL FORECAST SOUNDINGS INDICATE
MODERATE MIXING POTENTIAL WITH MANY AREAS SEEING 30-35 MPH GUSTS
OR HIGHER. EXPECT HIGHER TERRAIN OF THE NORTH AND WEST TO SEE SCT
-SHRA...WHILE CENTRAL AND SOUTHEAST AREAS REMAIN PARTLY SUNNY AND
DRY.
HIGHS WILL RANGE FROM JUST 60 TO 65F ACROSS THE NORTHWEST MTNS...TO
THE LOWER 80S THROUGHOUT THE LOWER SUSQ RIVER VALLEY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
STILL LOOKING AT A FEW SHOWERS ACROSS THE NORTH TUESDAY NIGHT
INTO WED...WITH THE COLD AIR ALOFT.
IT WILL BE BREEZY AND COLDER FROM LATE TUE INTO THU MORNING.
LATER SHIFTS WILL NEED TO MONITOR THE NEED FOR FROST AND
FREEZE PRODUCTS.
MID SHIFT INSERTED SHOWERS INTO THE FCST FOR FRIDAY INTO SAT.
THIS BASED ON WEAK SYSTEM DROPPING SE. WHILE MOISTURE MAY BE
LIMITED...DIRECTIONAL SHEAR WILL BE THERE. I DID CUT BACK
ON THE SHOWERS SOME ON THE FIRST PART OF FRIDAY.
DID ADJUST POPS SOME FOR SUNDAY...AS SYSTEM DROPS SE OF OUR
AREA...DID CUT BACK SOME.
FOR MONDAY...ADJUSTED POPS SOME MORE...AS WE WILL BE ON THE
EASTERN AND NORTHERN EDGE OF THE WARM ADVECTION.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
RADAR AT 06Z SHOWS ONE LINE OF SHRA/TSRA PUSHING THRU EASTERN PA
AND ANOTHER BATCH OF SHRA ASSOC WITH APPROACHING COLD FRONT OVER
WESTERN PA. FOR MUCH OF CENTRAL PA...NO SIG CIG/VIS REDUCTIONS
ARE EXPECTED EARLY THIS MORNING. THE EXCEPTION COULD BE KBFD AND
KJST...WHERE A BRIEF PERIOD OF IFR CIGS MAY DEVELOP AS PLUME OF
MOIST AIR ALONG COLD FRONT ASCENDS THE W MTNS. MDL RH TIMESECTIONS
AND HRRR OUTPUT SUGGEST THE WINDOW OF OPPORTUNITY FOR IFR CONDS AT
KBFD/KJST WILL BE 09Z-11Z. AFTER 11Z...DRIER AIR WILL ARRIVE ON
WEST WIND...CAUSING IMPROVING CONDS.
WIDESPREAD VFR CONDS EXPECTED AFTER SUNRISE...AS DRIER AIR FLOWS
IN BEHIND COLD FRONT. MAIN CONCERN TODAY WILL BE THE GUSTY WEST
WINDS...RESULTING FROM TIGHT PRESSURE GRADIENT SOUTH OF LOW PRES
OVR S QUEBEC. MDL SOUNDINGS SUPPORT GUSTS BTWN 25-30KTS BY THIS
AFTN. THE STRONGEST GUSTS WILL DIMINISH AFTER SUNSET...BUT IT
WILL REMAIN BREEZY OVERNIGHT.
OUTLOOK...
WED...NO SIG WX EXPECTED.
THU...EARLY AM FOG POSS NW MTNS.
FRI...PM SHRA/CIG REDUCTIONS POSS...MAINLY NW MTNS.
SAT...SCT PM TSRA IMPACTS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR/LAMBERT
NEAR TERM...DANGELO/LAMBERT
SHORT TERM...DEVOIR
LONG TERM...MARTIN
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
237 AM EDT TUE MAY 12 2015
.SYNOPSIS...
SUMMERTIME WARMTH AND HUMIDITY WILL COME TO AN END LATE TONIGHT
AND TUESDAY AS A VIGOROUS UPPER TROF AND ASSOCIATED COLD FRONT
CROSSES THE REGION. COOLER...DRIER AND WINDY CONDITIONS WILL
ARRIVE DURING THE DAYLIGHT HOURS TUESDAY...AND LAST THROUGH
WEDNESDAY NIGHT. MILDER CONDITIONS WILL RETURN FOR THURSDAY AND
FRIDAY AND CONTINUE THIS WEEKEND AS ANOTHER UPPER RIDGE BUILDS
ACROSS THE REGION.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
COLD POOL FROM THE STORMS OVER OH AND WRN PA HAVE MADE QUITE AN
ACTIVE EVENING AS IT FORMED INTO A NICE BOW ECHO. MANY DAMAGE
REPORTS WITH TREES NOW PRETTY MUCH LEAFED OUT EVERYWHERE. MESO
MDLS CONTINUE TO MAKE NO PRECIP TO THE SE OF AOO/UNV/IPT
OVERNIGHT. BUT ALLOWING FOR SOME CONTINUATION IN THE LINE OF
SHOWERS AS IT IS...BUT BUYING INTO THE WEAKENING/DISSIPATION A
LITTLE MORE AS THE LATEST ECHOES PLAY THAT THE GUST FRONT IS
RACING TOO FAR AHEAD OF THE SRN CELLS. THIS BODES WELL FOR
WEAKENING THERE. LEFT IN JUST A 30 POP FOR AN HR OR TWO FOR THE
SERN COS. COLD AIR SEEMS LIKE IT COMES IN TWO WAVES...WITH THE
FIRST SURGE LATER TONIGHT BEING ACCOMPANIED BY MORE
SHOWERS...MAINLY ACROSS THE NW MTNS. A SECONDARY FRONT IN THE
MORNING WILL ALSO MAKE A FEW SHRA.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH 6 PM WEDNESDAY/...
FRONT CLEARS SOUTHEASTERN COUNTIES EARLY TUESDAY...WITH WINDY AND
DRIER CONDITIONS IN STORE FOR MOST OF THE REGION. MODEL FORECAST
SOUNDINGS INDICATE MODERATE MIXING POTENTIAL WITH MANY AREAS
SEEING 30-35 MPH GUSTS OR HIGHER. EXPECT HIGHER TERRAIN OF THE
NORTH AND WEST TO SEE SCT -SHRA...WHILE CENTRAL AND SOUTHEAST
AREAS REMAIN PARTLY SUNNY AND DRY.
HIGHS WILL RANGE FROM THE UPPER 60S NORTHWEST TO THE LOWER 80S
LOWER SUSQ RIVER VALLEY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
STILL LOOKING AT A FEW SHOWERS ACROSS THE NORTH TUESDAY NIGHT
INTO WED...WITH THE COLD AIR ALOFT.
IT WILL BE BREEZY AND COLDER FROM LATE TUE INTO THU MORNING.
LATER SHIFTS WILL NEED TO MONITOR THE NEED FOR FROST AND
FREEZE PRODUCTS.
MID SHIFT INSERTED SHOWERS INTO THE FCST FOR FRIDAY INTO SAT.
THIS BASED ON WEAK SYSTEM DROPPING SE. WHILE MOISTURE MAY BE
LIMITED...DIRECTIONAL SHEAR WILL BE THERE. I DID CUT BACK
ON THE SHOWERS SOME ON THE FIRST PART OF FRIDAY.
DID ADJUST POPS SOME FOR SUNDAY...AS SYSTEM DROPS SE OF OUR
AREA...DID CUT BACK SOME.
FOR MONDAY...ADJUSTED POPS SOME MORE...AS WE WILL BE ON THE
EASTERN AND NORTHERN EDGE OF THE WARM ADVECTION.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
RADAR AT 06Z SHOWS ONE LINE OF SHRA/TSRA PUSHING THRU EASTERN PA
AND ANOTHER BATCH OF SHRA ASSOC WITH APPROACHING COLD FRONT OVER
WESTERN PA. FOR MUCH OF CENTRAL PA...NO SIG CIG/VIS REDUCTIONS
ARE EXPECTED EARLY THIS MORNING. THE EXCEPTION COULD BE KBFD AND
KJST...WHERE A BRIEF PERIOD OF IFR CIGS MAY DEVELOP AS PLUME OF
MOIST AIR ALONG COLD FRONT ASCENDS THE W MTNS. MDL RH TIMESECTIONS
AND HRRR OUTPUT SUGGEST THE WINDOW OF OPPORTUNITY FOR IFR CONDS AT
KBFD/KJST WILL BE 09Z-11Z. AFTER 11Z...DRIER AIR WILL ARRIVE ON
WEST WIND...CAUSING IMPROVING CONDS.
WIDESPREAD VFR CONDS EXPECTED AFTER SUNRISE...AS DRIER AIR FLOWS
IN BEHIND COLD FRONT. MAIN CONCERN TODAY WILL BE THE GUSTY WEST
WINDS...RESULTING FROM TIGHT PRESSURE GRADIENT SOUTH OF LOW PRES
OVR S QUEBEC. MDL SOUNDINGS SUPPORT GUSTS BTWN 25-30KTS BY THIS
AFTN. THE STRONGEST GUSTS WILL DIMINISH AFTER SUNSET...BUT IT
WILL REMAIN BREEZY OVERNIGHT.
OUTLOOK...
WED...NO SIG WX EXPECTED.
THU...EARLY AM FOG POSS NW MTNS.
FRI...PM SHRA/CIG REDUCTIONS POSS...MAINLY NW MTNS.
SAT...SCT PM TSRA IMPACTS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DANGELO
SHORT TERM...DEVOIR
LONG TERM...MARTIN
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
136 PM EDT TUE MAY 12 2015
.SYNOPSIS...
A WEAK COLD FRONT WILL CROSS OUR AREA TODAY...BEFORE STRONG HIGH
PRESSURE BUILDS IN FROM THE NORTH AND REMAINS THROUGH FRIDAY.
MOISTURE WILL SPREAD OVER THE AREA AHEAD OF ANOTHER COLD FRONT THAT
APPROACHES FROM THE WEST EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 130 PM EDT...RADAR HAS BEEN RELATIVELY QUIET EARLY THIS
AFTERNOON AS A COLD FRONT SLIPS SLOWLY EASTWARD ACROSS THE REGION.
HOWEVER...THE HRRR CONTINUES TO INSIST ON SCATTERED CONVECTIVE
DEVELOPMENT ALONG THE PASSING COLD FRONT...WITH PEAK PIEDMONT
COVERAGE CIRCA 19Z TO 20Z. THIS IS SOMEWHAT CONSISTENT WITH SB CAPE
VALUES OF 1000 TO 1500 J/KG OR GREATER OVER THE ERN PIEDMONT PARTS
OF OUR FORECAST AREA...AND ALSO WITH MODEL PROFILES FINALLY
OVERCOMING LOW LEVEL CINH AROUND THAT TIME. HOWEVER...THE MID DECK
OF CLOUDS HAS GREATLY LIMITED HEATING FOR MUCH OF THE AREA...SO
EXPECT THAT ANY ISOLD TO SCT CONVECTION THAT DOES FORM WILL BE
RATHER WEAK.
OTHERWISE...THE SFC COLD FRONT WILL SETTLE SOUTHEAST OF THE AREA
THIS EVENING WITH DRIER HIGH PRESSURE BUILDING OVER TO THE N THROUGH
WED. WEAK CHANNELED VORTICITY WILL SLIDE EAST ACROSS THE AREA
OVERNIGHT TO PRODUCE SOME HIGH LEVEL CLOUDINESS...BUT WITH LOWER
LEVELS DRY. EXPECT MINS TO FALL INTO THE 40S MTNS AND 50S PIEDMONT
UNDER WEAK COLD ADVECTION. HEIGHT RISES WILL DEVELOP FROM THE WEST
ON WED WITH COMFORTABLE MAXES NEAR CLIMO.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
AT 300 AM EDT TUESDAY...ON WEDNESDAY MORNING AN UPPER TROUGH WILL BE
ALONG THE EAST COAST...WHILE AND UPPER RIDGE WILL EXTEND FROM THE
GULF STATES TO THE NORTHERN PLAINS. BY THURSDAY THIS NEGATIVELY
TILTED RIDGE WILL EXTEND FROM FL TO THE UPPER MS RIVER VALLEY. A
STRONG SHORTWAVE WILL ACROSS THE MS RIVER VALLEY ON THURSDAY...
WEAKENING AS IT MOVES THROUGH THE RIDGE AXIS ON THURSDAY NIGHT.
AT THE SURFACE...ON WEDNESDAY DRY HIGH PRESSURE CENTERED OVER THE
GREAT LAKES WILL BUILD SOUTH ACROSS OUR AREA IN THE WAKE OF A
DEPARTING COLD FRONT. AS THE HIGH MOVES EAST ON THURSDAY...IT
EXTENDS SOUTH ALONG THE EAST SLOPES OF THE APPALACHIANS. ON
THURSDAY NIGHT...ISENTROPIC UPGLIDE OVER THE HIGH SETS THE STAGE FOR
PRECIPITATION...MAINLY OVER THE MOUNTAINS. TEMPERATURES WILL START
OUT SLIGHTLY ABOVE NORMAL IN DOWNSLOPE WARMING BEHIND THE
FRONT...FALLING TO NEAR NORMAL AS THE COOLER AIR MASS ARRIVES AND
LOW LEVEL FLOW VEERS TO NE.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AT 135 PM EDT TUESDAY...HIGH CONFIDENCE IS HAD THROUGHOUT THE EXT
PERIOD. GOOD INDIVIDUAL RUN TO RUN AND MODEL TO MODEL CONSISTENCY
CONTINUES TO INDICATE A BUILDING H5 RIDGE SAT BECOMING REINFORCED ON
SUN...THEN SLOWLY BREAKING DOWN MON THROUGH TUE. THERE ARE SOME
SUBTLE DIFFERENCES IN IN THE MAGNITUDE AND LOCATION OF THE RIDGE
AXIS...HOWEVER NOT ENOUGH DIFFERENCES TO IMPACT THE SENSIBLE WX
SIGFNTLY.
AT THE SFC...THE MAIN SYNOPTIC FEATURE WILL BE A MID ATL HIGH
MERGING WITH THE BERMUDA HIGH CREATING A DOMINATE RIDGING PATTERN
ACROSS THE CWFA THROUGH MOST OF THE PERIOD. THIS SETUP WILL KEEP THE
MAIN STORM ACTIVITY AND HIGHER DEEP LAYERED INSTABILITY WEST OF THE
AREA SAT AND SUN...WITH ISOL/SCT PULSE MTN TSTMS PROBABLE EACH
AFTERNOON. THE SFC RIDGE WEAKENS ON MON WHICH WILL ALLOW HIGHER TD/S
NORTH AND INCREASE SBCAPE VALUES...ENUF SO FOR MENTION OF DIURNAL
THUNDER ACROSS ALL ZONES. WITH LIMITED ULVL ENERGY...THE ATMOS WILL
BE IN A TYPICAL SUMMERTIME PATTERN WITH SCT PULSE SEVERE STORMS
POSSIBLE EACH AFTERNOON MON/TUE. WITH CONTINUED RIDGING AND SW/LY
LLVL FLOW...MAX TEMPS WILL BEGIN RIGHT AROUND NORMAL SAT AND
INCREASE TO A COUPLE CATS ABOVE NORMAL BY TUE.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
AT KCLT...MID CLOUDS THROUGH MIDDAY HAVE LIMITED HEATING AND
INSTABILITY. WILL THUS CONTINUE TO FEATURE ONLY VCSH WITH THE FROPA
THIS AFTN. OTHERWISE...EXPECT WSW WINDS TO TOGGLE NW WITH FROPA
TOWARD EVENING AND THEN TURN NRLY AND NE OVERNIGHT INTO WED MORNING.
ANY CIGS SHOULD BE MID AND HIGH CLOUDS...WITH HIGHER CLOUDS THINNING
LATER IN THE PERIOD.
ELSEWHERE...MORNING MID CLOUDS HAVE LIMITED INSTABILITY...WHICH
SHOULD KEEP FOOTHILL TAFS DRY THIS AFTN. THE FROPA IS THROUGH
KAVL...SO DRY AND VFR CONDITIONS WILL CONTINUE THERE AS WELL...WITH
OCNL NW GUSTS. FOOTHILL WINDS WILL TOGGLE NW THROUGH LATE AFTN AND
NRLY THEN NE OVERNIGHT THROUGH WED MORNING. LITTLE MORE THAN HIGH
CLOUDS ARE THEN EXPECTED THE LATER HALF OF THE PERIOD.
OUTLOOK...DRIER AIR WILL SETTLE IN UNDER BUILDING HIGH PRESSURE
THROUGH THU. RETURN FLOW MOISTURE AROUND THE HIGH PRESSURE MAY ALLOW
DIURNAL SHOWERS AND THUNDERSTORMS TO RETURN TO THE AREA FRIDAY
THROUGH THE WEEKEND...ESPECIALLY OVER THE MTNS.
CONFIDENCE TABLE...
17-23Z 23-05Z 05-11Z 11-12Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...JAT
NEAR TERM...HG
SHORT TERM...JAT
LONG TERM...JAT
AVIATION...HG
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1112 AM MDT TUE MAY 12 2015
.UPDATE...
ISSUED AT 938 AM MDT TUE MAY 12 2015
15Z SURFACE ANALYSIS HAD FRONTAL BOUNDARY FROM NORTHWEST WY INTO
SOUTHWEST SD. LIFT UNDER RIGHT ENTRANCE REGION OF JET STREAK
ACROSS THE NORTHERN PLAINS ASSISTING SOME WEAKER RETURNS ON RADAR
ACROSS FAR NORTHEAST WY/SOUTHEAST MT/ENTERING NORTHWEST SD. MOST
OF IT NOT REACHING THE GROUND...AND LOOKING AT THE 12Z KUNR
SOUNDING THERE IS SOME DRY AIR TO OVERCOME.
12Z RAP SHOWS A BIT OF SBCAPE OVER THE HIGHER TERRAIN AS DECENT
SOUTHERLY FLOW FEEDS MOISTURE POOLING ALONG THE BOUNDARY SO HAVE
ADDED SMALL POPS LATER THIS AFTERNOON FOR THOSE AREAS.
&&
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
ISSUED AT 300 AM MDT TUE MAY 12 2015
WESTERN CONUS UPPER LEVEL TROUGHING ONGOING THIS MORNING WITH A
LOCAL WAA RESPONSE. WEAK LEAD IMPULSE FROM THIS SYSTEM WILL
SUPPORT INCREASING MID/HIGH CLOUDS THROUGH MORNING ACROSS THE
NORTHERN HALF...WITH A FEW SPRINKLES POSSIBLE ACROSS THE FAR
NORTH. MEANWHILE ANOTHER UPPER LEVEL IMPULSE WILL SHIFT NE INTO
THE SW CONUS AND SOUTHERN PLAINS. THIS SYSTEM WILL HELP SUPPORT
DEEPER MOISTURE NORTH INTO THE AREA THROUGH TONIGHT. ONGOING
PRESSURE FALLS PER THE ADVANCING WESTERN CONUS UPPER TROUGH WILL
SUPPORT A LLJ TONIGHT WITH SOME FORCING FOR ASCENT PER A SLOW
MOVING NW CONUS UPPER TROUGH GRAZING THE NORTHERN PLAINS TONIGHT.
STEEP MID LEVEL LAPSE RATE WITH AN FGEN RESPONSE AND INCREASING
ELEVATED INSTABILITY NOTED IN MU CAPES WILL SUPPORT A SLIGHT
CHANCE SHOWER/TS THREAT ACROSS THE NORTHERN HALF TONIGHT. HIRES
MODELS INCLUDING THE NAM SUGGEST AN ISOLD HIGH BASED SHRA/TS COULD
DEVELOP OVER NE WY THIS EVENING AS CIN IS MINIMIZED PER
INSOLATION...WITH ANY ACTIVITY BEING CARRIED NE BY A DEVELOPING
LLJ. DID ADJUST SLIGHT CHANCE POPS SW INTO NE WY AND THE BH AFTER
00Z THIS EVENING FOR THIS...WITH A SLIGHTLY EARLIER START TIME
POSSIBLE. LEE SIDE TROUGH WILL SHIFT EAST ACROSS THE FA WED
MORNING AND STALL WITH THE SOUTHERN PLAINS IMPULSE SHIFTING NORTH.
RENEWED FGEN FROM THIS SYSTEM WILL SUPPORT INCREASING LL
CONVERGENCE ALONG AND NEAR THE SFC TROUGH WHICH WILL BE SOMEWHERE
ACROSS THE EASTERN FA. INCREASING LL MOISTURE COMBINED WITH
DIURNAL INSTABILITY WILL ALLOW INCREASING CHANCES FOR SHRA/TS
THERE...WITH OTHER ACTIVITY POSSIBLE OVER THE BH AND NE WY PER
DIURNAL HEATING IN THE PRESENCE OF UNSTABLE PROFILES/WEAK CIN.
SHRA/TS CHANCES SHOULD INCREASE WED NIGHT AS THE LLJ SUSTAINED
WITH ONGOING MOISTURE TRANSPORT AND INCREASING LSA FROM THE
EXPECTED IMPULSE. BULK OF FORCING FROM THIS SYSTEM WILL REMAIN SE
OF THE FA...INCLUDING THE ASSOCIATED PRECIP CHANCES. HAVE RETAINED
HIGH CHANCE POPS...PRECLUDING LIKELY ATTM GIVEN CONVECTIVE
COMPONENT TO PRECIP.
AS FOR TEMPS...BUMPED HIGHS UP BOTH TODAY AND WED. SNOW PACK HAS
ERODED QUITE WELL OVER MUCH OF THE AREA...WITH THE DEEPEST SNOW
REMAINING OVER SW SD. STRONG SE WINDS UNDER MAY SUN SHOULD MIX
WARMER AIR DOWN WITH NO PROBLEM...THUS HAVE OPTED FOR TEMPS MORE
IN LINE WITH GUIDANCE.
.LONG TERM...THURSDAY THROUGH MONDAY
ISSUED AT 300 AM MDT TUE MAY 12 2015
THE UPPER LEVEL RIDGE WILL MOVE EAST OF THE AREA ON WEDNESDAY.
THIS WILL PUT THE AREA IN ACTIVE SOUTHWEST FLOW FOR MID WEEK INTO
THE WEEKEND...WITH DAILY CHANCES FOR RAIN SHOWERS AND SOME
THUNDERSTORMS. A FAST-MOVING SHORTWAVE WILL SWEEP THROUGH THE
CENTRAL CONUS WEDNESDAY NIGHT AND THURSDAY...AND THEN ANOTHER
UPPER LOW IS PROGGED TO MOVE ACROSS THE ROCKIES AND INTO THE
PLAINS THIS WEEKEND...BRINGING THE BEST CHANCES FOR ADDITIONAL
RAINFALL. MODELS ARE INDICATING AROUND A HALF INCH OF QPF BY THE
END OF THE WEEK...WITH AN ADDITIONAL INCH OR TWO DURING THE
WEEKEND. AS FAR AS TEMPERATURES GO...MORE SPRING LIKE READINGS ARE
EXPECTED FROM MID WEEK THROUGH THE WEEKEND. THEREFORE...THE
PRECIPITATION SHOULD REMAIN RAIN.
&&
.AVIATION...FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY
ISSUED AT 1110 AM MDT TUE MAY 12 2015
GUSTY SOUTHERLY WINDS ACROSS SOUTH CENTRAL SD WILL DIMINISH THIS
EVENING. NORTHWEST SD INTO NORTHEAST WY AND THE BLACK HILLS HAVE A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS THIS EVENING AND
OVERNIGHT. GENERALLY VFR CONDITIONS ARE EXPECTED THROUGH WEDNESDAY
MORNING...ALTHOUGH THERE MAY BE SOME LOCAL MFVR CIGS WITH ANY
SHOWERS AND THUNDERSTORMS. MODELS ARE IN DISAGREEMENT ON THE
POSSIBLE DEVELOPMENT OF FOG ACROSS NORTHEAST WY AND AREAS JUST
EAST OF THE BH. COULD BE SOME LOW STRATUS...BUT WILL KEEP TAFS VFR
FOR NOW.
&&
.HYDROLOGY...
ISSUED AT 300 AM MDT TUE MAY 12 2015
RUNOFF FROM RAIN AND MELTING SNOW IS CAUSING RAPID RISES IN THE
LEVEL OF THE WHITE RIVER BETWEEN INTERIOR AND OACOMA. A FLOOD
WARNING HAS BEEN ISSUED FOR THAT AREA AS MINOR TO MODERATE
FLOODING IS FORECAST TO DEVELOP STARTING TUESDAY MORNING.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...7
AVIATION...POJORLIE
HYDROLOGY...JC
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
950 AM MDT TUE MAY 12 2015
.UPDATE...
ISSUED AT 938 AM MDT TUE MAY 12 2015
15Z SURFACE ANALYSIS HAD FRONTAL BOUNDARY FROM NORTHWEST WY INTO
SOUTHWEST SD. LIFT UNDER RIGHT ENTRANCE REGION OF JET STREAK
ACROSS THE NORTHERN PLAINS ASSISTING SOME WEAKER RETURNS ON RADAR
ACROSS FAR NORTHEAST WY/SOUTHEAST MT/ENTERING NORTHWEST SD. MOST
OF IT NOT REACHING THE GROUND...AND LOOKING AT THE 12Z KUNR
SOUNDING THERE IS SOME DRY AIR TO OVERCOME.
12Z RAP SHOWS A BIT OF SBCAPE OVER THE HIGHER TERRAIN AS DECENT
SOUTHERLY FLOW FEEDS MOISTURE POOLING ALONG THE BOUNDARY SO HAVE
ADDED SMALL POPS LATER THIS AFTERNOON FOR THOSE AREAS.
&&
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
ISSUED AT 300 AM MDT TUE MAY 12 2015
WESTERN CONUS UPPER LEVEL TROUGHING ONGOING THIS MORNING WITH A
LOCAL WAA RESPONSE. WEAK LEAD IMPULSE FROM THIS SYSTEM WILL
SUPPORT INCREASING MID/HIGH CLOUDS THROUGH MORNING ACROSS THE
NORTHERN HALF...WITH A FEW SPRINKLES POSSIBLE ACROSS THE FAR
NORTH. MEANWHILE ANOTHER UPPER LEVEL IMPULSE WILL SHIFT NE INTO
THE SW CONUS AND SOUTHERN PLAINS. THIS SYSTEM WILL HELP SUPPORT
DEEPER MOISTURE NORTH INTO THE AREA THROUGH TONIGHT. ONGOING
PRESSURE FALLS PER THE ADVANCING WESTERN CONUS UPPER TROUGH WILL
SUPPORT A LLJ TONIGHT WITH SOME FORCING FOR ASCENT PER A SLOW
MOVING NW CONUS UPPER TROUGH GRAZING THE NORTHERN PLAINS TONIGHT.
STEEP MID LEVEL LAPSE RATE WITH AN FGEN RESPONSE AND INCREASING
ELEVATED INSTABILITY NOTED IN MU CAPES WILL SUPPORT A SLIGHT
CHANCE SHOWER/TS THREAT ACROSS THE NORTHERN HALF TONIGHT. HIRES
MODELS INCLUDING THE NAM SUGGEST AN ISOLD HIGH BASED SHRA/TS COULD
DEVELOP OVER NE WY THIS EVENING AS CIN IS MINIMIZED PER
INSOLATION...WITH ANY ACTIVITY BEING CARRIED NE BY A DEVELOPING
LLJ. DID ADJUST SLIGHT CHANCE POPS SW INTO NE WY AND THE BH AFTER
00Z THIS EVENING FOR THIS...WITH A SLIGHTLY EARLIER START TIME
POSSIBLE. LEE SIDE TROUGH WILL SHIFT EAST ACROSS THE FA WED
MORNING AND STALL WITH THE SOUTHERN PLAINS IMPULSE SHIFTING NORTH.
RENEWED FGEN FROM THIS SYSTEM WILL SUPPORT INCREASING LL
CONVERGENCE ALONG AND NEAR THE SFC TROUGH WHICH WILL BE SOMEWHERE
ACROSS THE EASTERN FA. INCREASING LL MOISTURE COMBINED WITH
DIURNAL INSTABILITY WILL ALLOW INCREASING CHANCES FOR SHRA/TS
THERE...WITH OTHER ACTIVITY POSSIBLE OVER THE BH AND NE WY PER
DIURNAL HEATING IN THE PRESENCE OF UNSTABLE PROFILES/WEAK CIN.
SHRA/TS CHANCES SHOULD INCREASE WED NIGHT AS THE LLJ SUSTAINED
WITH ONGOING MOISTURE TRANSPORT AND INCREASING LSA FROM THE
EXPECTED IMPULSE. BULK OF FORCING FROM THIS SYSTEM WILL REMAIN SE
OF THE FA...INCLUDING THE ASSOCIATED PRECIP CHANCES. HAVE RETAINED
HIGH CHANCE POPS...PRECLUDING LIKELY ATTM GIVEN CONVECTIVE
COMPONENT TO PRECIP.
AS FOR TEMPS...BUMPED HIGHS UP BOTH TODAY AND WED. SNOW PACK HAS
ERODED QUITE WELL OVER MUCH OF THE AREA...WITH THE DEEPEST SNOW
REMAINING OVER SW SD. STRONG SE WINDS UNDER MAY SUN SHOULD MIX
WARMER AIR DOWN WITH NO PROBLEM...THUS HAVE OPTED FOR TEMPS MORE
IN LINE WITH GUIDANCE.
.LONG TERM...THURSDAY THROUGH MONDAY
ISSUED AT 300 AM MDT TUE MAY 12 2015
THE UPPER LEVEL RIDGE WILL MOVE EAST OF THE AREA ON WEDNESDAY.
THIS WILL PUT THE AREA IN ACTIVE SOUTHWEST FLOW FOR MID WEEK INTO
THE WEEKEND...WITH DAILY CHANCES FOR RAIN SHOWERS AND SOME
THUNDERSTORMS. A FAST-MOVING SHORTWAVE WILL SWEEP THROUGH THE
CENTRAL CONUS WEDNESDAY NIGHT AND THURSDAY...AND THEN ANOTHER
UPPER LOW IS PROGGED TO MOVE ACROSS THE ROCKIES AND INTO THE
PLAINS THIS WEEKEND...BRINGING THE BEST CHANCES FOR ADDITIONAL
RAINFALL. MODELS ARE INDICATING AROUND A HALF INCH OF QPF BY THE
END OF THE WEEK...WITH AN ADDITIONAL INCH OR TWO DURING THE
WEEKEND. AS FAR AS TEMPERATURES GO...MORE SPRING LIKE READINGS ARE
EXPECTED FROM MID WEEK THROUGH THE WEEKEND. THEREFORE...THE
PRECIPITATION SHOULD REMAIN RAIN.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 300 AM MDT TUE MAY 12 2015
GUSTY SOUTHERLY WINDS ARE EXPECTED OVER NORTHEASTERN WYOMING
DURING THE REST OF THE NIGHT. THERE IS A SLIGHT CHANCE OF SHOWERS
AND THUNDERSTORMS ON TUESDAY EVENING. LCL MVFR CIGS ARE POSSIBLE
WITH ANY SHOWERS OR THUNDERSTORMS...OTHERWISE VFR CIGS WILL
PREVAIL.
&&
.HYDROLOGY...
ISSUED AT 300 AM MDT TUE MAY 12 2015
RUNOFF FROM RAIN AND MELTING SNOW IS CAUSING RAPID RISES IN THE
LEVEL OF THE WHITE RIVER BETWEEN INTERIOR AND OACOMA. A FLOOD
WARNING HAS BEEN ISSUED FOR THAT AREA AS MINOR TO MODERATE
FLOODING IS FORECAST TO DEVELOP STARTING TUESDAY MORNING.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...7
AVIATION...7
HYDROLOGY...JC
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
1258 AM CDT TUE MAY 12 2015
.DISCUSSION...UPDATED FOR 06Z AVIATION.
&&
.AVIATION...CONVECTION IS THE MAIN AVIATION CONCERN IN THE SHORT
TERM. LINE OF SHOWERS AND STORMS CONTINUES TO MOVE W TO E ACROSS
SOUTH TEXAS. KEPT SHRA/TSRA REMARKS IN THE TAFS FOR THE NEXT
SEVERAL HOURS. LOCALLY REDUCED VSBYS AND ERRATIC WINDS WILL OCCUR
IF THUNDERSTORMS DIRECTLY IMPACT TAFS. LAST COUPLE OF HRRR RUNS
INDICATE THERE COULD BE A LULL IN ACTIVITY LATER THIS MORNING AS
THIS ROUND OF STORMS MOVES OFF TO THE EAST. HOWEVER...ADDITIONAL
ACTIVITY WILL BE POSSIBLE AGAIN TODAY AS MOIST AIRMASS AND
BOUNDARY REMAINS IN THE AREA. IFR/MVFR CEILINGS TONIGHT SHOULD
TRANSITION TO MOSTLY MVFR/LOW END VFR DURING THE DAY ON TUESDAY.
OUTSIDE OF THUNDERSTORMS...WINDS WILL GENERALLY BE OUT OF THE EAST
AND ESE.
&&
.PREV DISCUSSION... /ISSUED 924 PM CDT MON MAY 11 2015/
DISCUSSION...OTHER THAN THE IMPRESSIVE SUPERCELL THAT SAT OVER
SOUTHERN DUVAL COUNTY FOR AWHILE BEFORE MOVING EAST-SOUTHEAST TO
THE FALFURRIAS AREA...CONVECTION HAS BEEN GENERALLY DISORGANIZED.
SURFACE TO 6 KM SHEAR WAS NOT QUITE AS STRONG AS ANTICIPATED AS
WELL AS SLIGHTLY LOWER INSTABILITY DUE TO CLOUD COVER. BUT 00Z CRP
SOUNDING STILL SHOWED MEAN LAYER CAPE AROUND 2500 J/KG AS MOISTURE
HAS INCREASED SUBSTANTIALLY WITH PRECIPITABLE WATER VALUES UP TO
2.15 INCHES. SLOW MOVING SUPERCELL OVER DUVAL COUNTY LIKELY
PRODUCED BETWEEN 7 AND 10 INCHES OF RAIN...BETWEEN BRUNI AND
REALITOS EARLIER THIS EVENING...AS STORM INGESTED THIS HIGHER
MOISTURE SOURCE ALONG THE COAST.
WATER VAPOR IMAGERY SHOWS A MID LEVEL SHORT WAVE TROUGH OVER
NORTHWEST MEXICO MOVING TO THE EAST. THE INCREASING MID AND UPPER
LEVEL FLOW ASSOCIATED WITH THIS SHORT WAVE TROUGH WILL MOVE OUT
OF NORTHEAST MEXICO INTO THE BRUSH COUNTRY OVERNIGHT. THIS WILL
INCREASE THE OVERALL SHEAR PROFILE THROUGH THE NIGHT. LATEST HI-
RES MODELS INDICATE THE POTENTIAL FOR A MORE ORGANIZED CONVECTIVE
COMPLEX TO FORM OVER THE RIO GRANDE PLAINS AND MOVE EAST-SOUTHEAST
LATER TONIGHT. INFRARED SATELLITE TRENDS SHOW COOLING CLOUD TOPS
WITH AREA OF CONVECTION FROM THE WESTERN HILL COUNTRY SOUTH TO
NORTHWEST OF LAREDO. HARD TO DISCERN WHERE FRONTAL BOUNDARY IS
WITH AREAS OF CONVECTION BUT THE BOUNDARY MAY BE OVER THE
NORTHERN COUNTIES AT THIS TIME. LOW LEVEL CONVERGENCE MAY BE
SLIGHTLY HIGHER NEAR THIS BOUNDARY WITH CONVECTION TO THE
NORTHWEST MOVING ALONG IT. WILL REMOVE THE MENTION OF SEVERE FOR
THE REST OF TONIGHT...ALTHOUGH THREAT FOR ISOLATED SEVERE STORMS
WILL STILL EXIST...AND RETAIN LOCALLY HEAVY RAINFALL IN FORECAST.
NO CHANGES MADE TO THE FLASH FLOOD WATCH AREA WITH BETTER THREAT
NEAR THE BOUNDARY AND OVER THE BRUSH COUNTRY AS ACTIVITY MOVES IN
FROM THE WEST.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 81 74 81 74 85 / 70 60 40 50 50
VICTORIA 80 70 81 72 84 / 70 60 50 50 50
LAREDO 82 71 84 71 88 / 80 70 60 60 50
ALICE 82 72 83 72 87 / 70 60 40 60 50
ROCKPORT 80 75 80 74 83 / 70 60 40 50 50
COTULLA 78 69 83 70 88 / 90 80 70 60 50
KINGSVILLE 83 73 83 73 87 / 70 60 40 50 50
NAVY CORPUS 80 75 80 75 83 / 70 60 40 50 50
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH THROUGH THIS AFTERNOON FOR THE FOLLOWING
ZONES: BEE...DUVAL...GOLIAD...LA SALLE...LIVE OAK...
MCMULLEN...VICTORIA...WEBB.
GM...NONE.
&&
$$
TB/78...AVIATION
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
325 PM CDT TUE MAY 12 2015
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 325 PM CDT TUE MAY 12 2015
FORECAST CONCERNS INCLUDE TEMPERATURES/FROST HEADLINES TONIGHT
AND THEN PRECIP/THUNDERSTORM CHANCES THROUGH EARLY NEXT WEEK.
DESPITE SOME MODEL TIMING DIFFERENCES FOR THURSDAY/S SYSTEM...
12.12Z MODEL SUITE IN GOOD OVERALL AGREEMENT THROUGH THURSDAY...
BUT THEN DIVERGE ON THE CONVECTIVE DETAILS FRIDAY INTO THE
WEEKEND. WILL USE A BLENDED MODEL APPROACH.
FOR TONIGHT...SURFACE RIDGE AXIS WILL SLIDE ACROSS THE UPPER MS
RIVER VALLEY...CENTERED ACROSS THE MN ARROWHEAD INTO NORTH-CENTRAL
WI BY 12Z WEDNESDAY. SHOULD SEE SOME INCREASING SOUTHEASTERLY
RETURN FLOW ACROSS SOUTHEAST MN AND NORTHEAST IA BY WEDNESDAY
MORNING...BUT FOR AREAS EAST OF THE MS RIVER...A WEAK PRESSURE
GRADIENT WILL LEAD TO CALM WINDS THROUGH THE NIGHT. IN ADDITION...
SIMULATED IR IMAGERY FROM THE NSSL WRF SUGGESTS CURRENT CU WILL
DISSIPATE AFTER SUNSET AND CIRRUS ACROSS THE DAKOTAS INTO CENTRAL
MN SHOULD REMAIN JUST WEST OF THE FORECAST AREA. AS A RESULT...
EXPECT MOSTLY CLEAR SKIES OVERNIGHT ALLOWING FOR MAXIMUM NOCTURNAL
COOLING. WILL HOIST A FROST ADVISORY FOR ALL WI COUNTIES EXCEPT
FOR BUFFALO/CRAWFORD/GRANT FROM MIDNIGHT THROUGH 7 AM WEDNESDAY
WHERE OVERNIGHT TEMPERATURES WILL FALL INTO THE UPPER 20S TO
MID 30S.
WARM AIR ADVECTION TO INCREASE ON WEDNESDAY ALLOWING TEMPERATURES
TO REBOUND BACK INTO THE UPPER 50S TO LOWER 60S. SOUTHEAST WINDS
TO INCREASE BETWEEN 10 AND 20 MPH AS SURFACE PRESSURE GRADIENT
STRENGTHENS ACROSS THE REGION. SHOULD SEE A FAIR AMOUNT OF SUN AS
CLOUDS/PRECIP WILL BE ANCHORED TO PRIMARY WARM FRONTAL BOUNDARY
FARTHER NORTH AND WEST ACROSS THE DAKOTAS INTO NORTHERN MN.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 325 PM CDT TUE MAY 12 2015
RAIN SHOWERS TO INCREASE FROM WEST TO EAST THURSDAY AND THURSDAY
NIGHT AS A SHORT-WAVE EJECTS INTO THE UPPER MIDWEST FROM A BROADER
PACIFIC TROUGH PARKED ALONG THE WEST COAST. FRONTOGENESIS IS
RATHER WEAK WITH THIS SYSTEM...BUT MODEST WARM AIR ADVECTION/
ISENTROPIC LIFT COMBINED WITH INCREASING MOISTURE TRANSPORT WILL
RESULT IN A SWATH OF SHOWERS MOVING ACROSS THE REGION. PWATS RISE
ABOVE ONE INCH...RESULTING IN WIDESPREAD ACCUMULATIONS OF AT LEAST
A HALF INCH AND POSSIBLY AN INCH OR HIGHER IN SOME PLACES. THUNDER
WILL NOT ACCOMPANY THIS SYSTEM AS INSTABILITY IS NEARLY NON-
EXISTENT. CLOUDS/RAIN WILL KEEP THURSDAY COOL WITH AFTERNOON HIGHS
ONLY IN THE UPPER 50S TO LOWER 60S.
CONVECTIVE POTENTIAL A BIT MURKY FRIDAY INTO SATURDAY. BEST
MOISTURE TRANSPORT FOCUSES ITSELF EITHER EAST OR WEST OF THE
FORECAST AREA AND WITH LITTLE UPPER LEVEL DYNAMIC SUPPORT GIVEN
STRENGTHENING RIDGE...THUNDERSTORM POTENTIAL IS UNCERTAIN. BEST
CHANCE WOULD BE SATURDAY WITH NORTHWARD SURGING WARM FRONT. FOR
NOW...WILL FOLLOW SUPERBLEND 20 TO 30 PERCENT CHANCES. OF GREATER
CERTAINTY WILL BE INCREASING TEMPERATURES WITH HIGHS IN THE 60S TO
LOWER 70S ON FRIDAY RISING INTO THE MID TO UPPER 70S FOR SATURDAY.
BETTER CHANCE FOR MORE ORGANIZED THUNDERSTORMS ON SUNDAY WITH
APPROACHING PACIFIC TROUGH AND COLD FRONT. MUCAPE AND BULK SHEAR
WITHIN THE 0 TO 6 KM LAYER INCREASE TO BETWEEN 1000 AND 1500 J/KG
AND 35 TO 40 KTS RESPECTIVELY...BUT ONGOING CONVECTION EARLIER IN
THE DAY COULD IMPACT AFTERNOON/EVENING THUNDERSTORM/SEVERE POTENTIAL.
THIS IS HIGHLIGHTED IN THE DAY 6 SPC OUTLOOK AND SOMETHING TO
WATCH THROUGH THE WEEK. DRIER/COOLER CONDITIONS RETURN MONDAY/
TUESDAY AFTER COLD FRONTAL PASSAGE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1201 PM CDT TUE MAY 12 2015
LOW LEVEL CYCLONIC FLOW AROUND THE SYSTEM EXITING THE NORTHERN
GREAT LAKES CONTINUES TO PRODUCE CLOUDS AND FEW SHOWERS ACROSS THE
AREA. FOR THE MOST PART...THE SHOWERS HAVE MOVED EAST OF BOTH TAF
SITES AND DO NOT ANTICIPATE THESE BEING A PROBLEM FOR THE
REMAINDER OF THE AFTERNOON. VISIBLE SATELLITE TRENDS SHOW THE
WESTERN PORTION OF THE CLOUD DECK IS BECOMING MORE OPEN CELLULAR
SUGGESTING THESE CLOUDS WILL DISSIPATE AT SOME POINT THIS
AFTERNOON. BOTH THE 12.15Z RAP AND 12.12Z NAM SUGGEST THE LOW
LEVEL MOISTURE FIELD WILL CONTINUE TO SLIDE EAST WITH THE
DEPARTING SYSTEM WITH THE CLOUDS SCATTERING OUT BY MID AFTERNOON.
UNTIL THIS HAPPENS...THE CEILINGS WILL FLUCTUATE BETWEEN MVFR AND
VFR. THESE LOWER CLOUDS WILL TOTALLY DISSIPATE WITH SUNSET THIS
EVENING AND THE WINDS WILL DIMINISH AS HIGH PRESSURE BUILDS IN.
THIS HIGH WILL QUICKLY SLIP EAST OF THE AREA WEDNESDAY MORNING
ALLOWING THE WINDS TO BECOME EAST AND INCREASE TO AROUND 10 KNOTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 7 AM CDT WEDNESDAY FOR
WIZ017-029-033-034-041>044-053-055.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ROGERS
LONG TERM...ROGERS
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1201 PM CDT TUE MAY 12 2015
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 334 AM CDT TUE MAY 12 2015
DEPARTING SHOWERS THIS MORNING/FROST POTENTIAL TONIGHT ARE THE MAIN
CONCERNS IN THE SHORT TERM.
CURRENT MAP ANALYSIS HAS DEEP 1002MB LOW JUST EAST OF LAKE SUPERIOR.
MEANWHILE...WATER VAPOR IMAGERY SHOWS A CLOSED LOW OVER NORTHEAST MN
WITH EMBEDDED SHORTWAVE TROUGH ENERGY ROTATING EASTWARD ACROSS
SOUTHERN MN/WESTERN WI. RADAR MOSAIC/SURFACE OBS INDICATING
SCATTERED SHOWER/DRIZZLE ACTIVITY MAINLY ALONG AND EAST OF THE
MISSISSIPPI BEING FORCED BY THESE EMBEDDED TROUGHS. OTHERWISE...
TEMPERATURES ACROSS THE AREA WERE IN THE 40S WITH SOMEWHAT
BRISK WESTERLY WINDS OF 10-20 MPH.
FOR TODAY...THE SURFACE/CLOSED MID-LEVEL LOW WILL SLOWLY PUSH
NORTHEAST OF THE AREA THIS MORNING WITH A RIDGE OF HIGH PRESSURE
BUILDING IN FROM THE WEST DURING THE AFTERNOON. KEPT SCATTERED
SHOWER MENTION IN FOR AREAS ALONG/N OF THE I-90/94 CORRIDORS THROUGH
THE MORNING HOURS...BUT THEN IT SHOULD BE DRY THROUGH THE AFTERNOON
WITH A SLOW EROSION OF CLOUD COVER FROM SOUTHWEST TO NORTHEAST AS
WELL. PLAN ON COOLER THAN NORMAL TEMPERATURES TODAY AS HIGHS ONLY
MAKE IT INTO THE UPPER 40S TO THE MIDDLE 50S. THESE COOLER
TEMPERATURES AND BRISK NORTHWEST WINDS WILL GIVE AN OVERALL RAW FEEL
TO THE DAY.
HIGH PRESSURE BUILDS INTO THE AREA TONIGHT FOR PARTLY CLOUDY SKIES
AND LIGHT WINDS. THIS WILL LEAD TO SOME CHILLY OVERNIGHT LOWS AS
READINGS DIP INTO THE 30S. WITH TEMPERATURES NEARING THE FREEZING
MARK...FEEL THE SAND COUNTRY OF CENTRAL WI WOULD BE MOST SUSCEPTIBLE
FOR FROST. HOWEVER...THERE IS SOME INDICATION OF HIGH/MID CLOUD
STREAMING IN FROM UPSTREAM WARM AIR ADVECTION ACROSS THE DAKOTAS/MN.
IN ADDITION...APPEARS THE RIDGE AXIS ACTUALLY PASSES INTO EASTERN WI
AFTER MIDNIGHT WHICH MAY BE ENOUGH TO PRODUCE SOME LIGHT EAST WIND
TO KEEP LOWER BOUNDARY LAYER MIXED ENOUGH TO PREVENT WIDESPREAD
FROST. BASED ON THESE UNCERTAINTIES...HAVE HELD OFF ON FROST
HEADLINES FOR NOW AND WILL LET THE DAYSHIFT ASSESS WITH MORE INPUT
FROM 12Z MODEL RUNS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 334 AM CDT TUE MAY 12 2015
PLAN SOME INCREASE IN MID/HIGH CLOUD ON WEDNESDAY IN RESPONSE TO
WARM FRONT PUSHING NORTH THROUGH MN. HOWEVER...DRY LOWER LAYERS
THANKS TO SURFACE HIGH PRESSURE OVER THE GREAT LAKES IS EXPECTED TO
KEEP THE AREA PRECIPITATION-FREE. PLAN ON HIGHS IN THE UPPER 50S TO
THE MIDDLE 60S WHICH IS STILL SOME 5 DEGREES BELOW NORMAL.
FOR LATER WEDNESDAY NIGHT THROUGH THURSDAY NIGHT...WILL BE WATCHING
A MID-LEVEL TROUGH MOVE FROM THE CENTRAL PLAINS INTO THE UPPER
MISSISSIPPI RIVER VALLEY REGION. FORCING FROM THIS WAVE AND AMPLE
850MB MOISTURE TRANSPORT ENOUGH TO DRIVE THE LIKELIHOOD OF SHOWERS.
VERY LIMITED/NIL CAPE SHOULD PREVENT ANY THUNDER POTENTIAL. AS SUCH
REMOVED ANY THUNDER MENTION. WITH CLOUD COVER/PRECIPITATION...
TEMPERATURES WILL SUFFER A BIT ON THURSDAY AS HIGHS ONLY TOP OFF IN
THE UPPER 50S TO THE LOWER 60S.
SOME LINGERING SHOWERS STILL POSSIBLE MAINLY FRIDAY MORNING AS THE
WAVE DEPARTS THE AREA. WITH BULK OF THIS SHOWER CHANCE IN THE
MORNING...APPEARS RIDGE OF HIGH PRESSURE AND INCREASING HEIGHTS WILL
RESULT IN HIGH TEMPERATURES WELL INTO THE 60S.
AFTER A DRY/PLEASANT SATURDAY WITH HIGHS LOOKING TO PUSH INTO THE
70S...ACTIVE WEATHER PATTERN SETTING UP FOR THE REST OF THE WEEKEND
INTO MONDAY. INCREASING SHOWERS AND THUNDERSTORM CHANCES WILL
OVERSPREAD THE AREA...MAINLY CENTERED ON SUNDAY AS A POTENT LOW
PRESSURE SYSTEM PUSHES TOWARD THE UPPER MISSISSIPPI RIVER VALLEY
REGION. APPEARS TO BE AMPLE BULK SHEAR...WITH GFS INDICATING 0-3KM
MUCAPE IN THE 500-1000J/KG RANGE SUNDAY AFTERNOON. BASED ON
THIS...THE POSSIBILITY IS THERE FOR A FEW SEVERE STORMS.
HOWEVER...UNCERTAINTY REMAINS GIVEN LIKELIHOOD OF ONGOING/MUDDLED
CONVECTION THROUGH THE DAY ON SUNDAY. WILL BE KEEPING A CLOSE EYE ON
THIS SITUATION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1201 PM CDT TUE MAY 12 2015
LOW LEVEL CYCLONIC FLOW AROUND THE SYSTEM EXITING THE NORTHERN
GREAT LAKES CONTINUES TO PRODUCE CLOUDS AND FEW SHOWERS ACROSS THE
AREA. FOR THE MOST PART...THE SHOWERS HAVE MOVED EAST OF BOTH TAF
SITES AND DO NOT ANTICIPATE THESE BEING A PROBLEM FOR THE
REMAINDER OF THE AFTERNOON. VISIBLE SATELLITE TRENDS SHOW THE
WESTERN PORTION OF THE CLOUD DECK IS BECOMING MORE OPEN CELLULAR
SUGGESTING THESE CLOUDS WILL DISSIPATE AT SOME POINT THIS
AFTERNOON. BOTH THE 12.15Z RAP AND 12.12Z NAM SUGGEST THE LOW
LEVEL MOISTURE FIELD WILL CONTINUE TO SLIDE EAST WITH THE
DEPARTING SYSTEM WITH THE CLOUDS SCATTERING OUT BY MID AFTERNOON.
UNTIL THIS HAPPENS...THE CEILINGS WILL FLUCTUATE BETWEEN MVFR AND
VFR. THESE LOWER CLOUDS WILL TOTALLY DISSIPATE WITH SUNSET THIS
EVENING AND THE WINDS WILL DIMINISH AS HIGH PRESSURE BUILDS IN.
THIS HIGH WILL QUICKLY SLIP EAST OF THE AREA WEDNESDAY MORNING
ALLOWING THE WINDS TO BECOME EAST AND INCREASE TO AROUND 10 KNOTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
555 AM EDT THU MAY 14 2015
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH TONIGHT. THE
HIGH WILL GRADUALLY SHIFT OFFSHORE THIS WEEKEND INTO EARLY NEXT
WEEK. A COLD FRONT WILL PUSH THROUGH THE AREA NEXT TUESDAY OR
WEDNESDAY. HIGH PRESSURE WILL THEN RETURN BY THURSDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FOG HAS BECOME A BIT MORE WIDESPREAD THAN EARLIER ANTICIPATED.
WEBCAMS...SURFACE OBSERVATIONS AND MEDIA REPORTS INDICATE THE FOG
IS LOCALLY DENSE AT TIMES WITH VISIBILITIES 1/4 MI OR LESS. GOES
FOG PRODUCTS SUGGESTS THE DENSE FOG MAY BE A BIT MORE WIDESPREAD
ACROSS PARTS OF SCREVEN...JENKINS AND BULLOCH COUNTIES. A DENSE
FOG ADVISORY MAY BE NEEDED FOR SOME COUNTIES IF THE DENSE FOG
CONTINUES TO EXPAND IN AREA.
TODAY...DEEP LAYERED HIGH PRESSURE WILL REMAIN IN TACT ACROSS THE
SOUTHEAST U.S. TODAY. HIGH RESOLUTION MODELS SUGGEST A NORTHEAST
WIND SURGE WORKING STEADILY DOWN THE NORTH CAROLINA COAST COULD
PROVIDE ENOUGH LOW-LEVEL CONVERGENCE TO SPREAD SOME ISOLATED
MARINE-BASED SHOWER ACTIVITY INLAND ACROSS PART OF UPPER
CHARLESTON AND EASTERN BERKELEY COUNTIES LATER THIS MORNING.
CONFIDENCE IS QUITE LOW IN THIS SCENARIO GIVEN HOW DRY THE LOWER
TROPOSPHERE IS ABOVE THE BOUNDARY LAYER SO WILL CARRY SOME VERY
LOW NON-ZERO POPS IN THIS AREA...BUT GENERALLY EXPECT DRY
CONDITIONS TO PREVAIL.
LOW-LEVEL MOISTURE RETURN WILL BEGIN TO SNEAK INTO THE FAR
SOUTHERN AND SOUTHWESTERN ZONES THIS AFTERNOON AS SURFACE HIGH
PRESSURE MOVES OFF THE MID-ATLANTIC COAST. FORECAST SOUNDINGS DO
NOT REALLY SUPPORT MUCH IN THE WAY OF MEANINGFUL INSTABILITY IN
THESE AREAS DESPITE THE SLOW EROSION OF THE CAPPING INVERSION.
WITH LITTLE/NO LOW-LEVEL CONVERGENCE EXPECTED ALONG THE PURE
/VERSUS RESULTANT/ SEA BREEZE CIRCULATION...POPS WILL BE KEPT
BELOW MENTIONABLE THRESHOLDS FOR NOW.
HIGHS WILL RANGE FROM THE LOWER 80S NORTH TO THE MID 80S CENTRAL
AND SOUTH...WARMEST ACROSS FAR INTERIOR SOUTHEAST GEORGIA. MID TO
UPPER 70S ARE LIKELY AT THE BEACHES WITH BREEZY ONSHORE WINDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
TONIGHT...LOW-LEVEL MOISTURE RETURN WILL CONTINUE THROUGH THE
NIGHT AS HIGH PRESSURE SHIFTS FARTHER OFFSHORE INTO THE WESTERN
ATLANTIC. MEAN MID-UPPER LEVEL RIDGING STILL LOOKS STRONG ENOUGH
TO PRECLUDE SHOWER ACTIVITY OVERNIGHT...BUT A BRIEF SPRINKLE OR
SHOWER CAN NOT BE COMPLETELY RULED OUT ACROSS SOUTHEAST GEORGIA
OVERNIGHT...MAINLY SOUTH OF THE I-16 CORRIDOR. WILL CONTINUE TO
HIGHLIGHT A DRY FORECAST FOR NOW GIVEN LOW CONFIDENCE IN ANY
MEASURABLE SHOWER ACTIVITY DEVELOPING. CLOUDS WILL THICKEN THROUGH
THE NIGHT WITH LOWS RANGING FROM THE LOWER 60S FAR NORTH TO THE
MID 60S ELSEWHERE.
SFC HIGH PRESSURE WILL BECOME CENTERED OVER THE WESTERN ATLANTIC BY
THE WEEKEND...SETTING UP EAST/SOUTHEAST FLOW THAT SLOWLY DEEPENS
MOISTURE OVER THE AREA AHEAD OF A SERIES OF SUBTLE H5 SHORTWAVES
THAT ROUND THE NORTHWEST FRINGE OF A MID LVL RIDGE CENTERED TO OUR
SOUTH. A SLIGHT CHANCE OF DIURNAL SHOWERS AND/OR THUNDERSTORMS WILL
BE POSSIBLE OVER INLAND PORTIONS OF SOUTHEAST GEORGIA ON FRIDAY AND
SATURDAY...FOLLOWED BY CHANCES OF AFTERNOON SHOWERS AND
THUNDERSTORMS ON SUNDAY...MAINLY AWAY FROM THE COAST WHERE LOW LVL
MOISTURE IS HIGHEST AND A SEABREEZE PROGRESSES INLAND. TEMPS SHOULD
BE A FEW DEGREES COOLER ON FRIDAY...IN THE UPPER 70S TO LOWER
80S...BUT A GRADUAL WARMING TREND IS ANTICIPATED THROUGH THE
WEEKEND. IN GENERAL...HIGH TEMPS SHOULD RANGE IN THE LOW TO MID 80S
ON SATURDAY...THEN MID TO UPPER 80S ON SUNDAY...WARMEST AWAY FROM
THE COAST.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
THE AREA WILL REMAIN ALONG THE WESTERN EDGE OF ATLANTIC HIGH
PRESSURE AND UNDER A LARGE MID LVL RIDGE EXTENDING NORTHWARD FROM
THE GULF OF MEXICO AND FLORIDA PENINSULA. THE PATTERN SHOULD RESULT
IN SOUTHERLY SFC FLOW INTO EARLY NEXT WEEK...ALLOWING MOISTURE TO
RETURN TO THE AREA WHILE WEAK H5 SHORTWAVES CONTINUE TO ROUND
NORTHWEST EDGE OF THE MID LVL RIDGE TO OUR SOUTH. CHANCES OF SHOWERS
AND/OR THUNDERSTORMS WILL BE POSSIBLE EACH AFTERNOON/EVENING INTO
EARLY NEXT WEEK...WITH HIGHEST COVERAGE INLAND. A COLD FRONT WILL
THEN APPROACH FROM THE NORTH/NORTHWEST ON TUESDAY BEFORE PUSHING
THROUGH THE AREA TUESDAY NIGHT INTO WEDNESDAY. HIGHER COVERAGE OF
SHOWERS AND THUNDERSTORMS CAN BE EXPECTED WITH COLD FROPA. HIGH
PRESSURE SHOULD THEN BUILD INTO THE AREA FROM THE NORTH/NORTHWEST
INTO THURSDAY.
TEMPS WILL BE ON A WARMING TREND NEXT WEEK...WITH MAX TEMPS REACHING
THE UPPER 80S TO LOWER 90S ON TUESDAY AHEAD OF THE APPROACHING COLD
FRONT. TEMPS SHOULD BE A FEW DEGREES COOLER ON WEDNESDAY AS HIGH
PRESSURE BUILDS BEHIND THE FRONT THROUGH THURSDAY. OVERNIGHT LOWS
SHOULD RANGE IN THE MID TO UPPER 60S AWAY FROM THE COAST.
&&
.AVIATION /10Z THURSDAY THROUGH MONDAY/...
VFR. EARLIER CONCERNS FOR IFR CIGS HAVE EASED A BIT BASED ON
LATEST HIGH RESOLUTION GUIDANCE. BOUNDARY LAYER JUST LOOKS TOO DRY
ABOVE THE SURFACE PER RAP FORECAST SOUNDINGS.
EXTENDED AVIATION OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PREVAIL
OUTSIDE SCATTERED DIURNAL CONVECTION LATE THIS WEEKEND AND EARLY
NEXT WEEK.
&&
.MARINE...
TODAY...A NORTHEAST WIND SURGE WILL OVERSPREAD THE WATERS TODAY
WITH DIRECTIONS SLOWLY VEERING TO THE EAST. WINDS LOOK TO GO NO
HIGHER THAN 15-20 KT FOR ALL LEGS WITH GUSTS HOLDING BELOW 25 KT.
SEAS WILL BUILD IN THE NORTHEAST FETCH...REACHING 3-5 FT NEARSHORE
WATERS AND A SOLID 5 FT FOR THE GEORGIA OFFSHORE WATERS BY LATE
THIS AFTERNOON. ATTM BOTH WINDS AND SEAS LOOK TO REMAIN BELOW
SMALL CRAFT ADVISORY LEVELS.
TONIGHT...MODEST ONSHORE WINDS WILL PERSIST...ALTHOUGH SPEEDS WILL
DIMINISH SOMEWHAT. WINDS ARE EXPECTED TO DROP TO 10-15 KT
NEARSHORE WATERS...BUT REMAIN 15-20 KT FOR THE GEORGIA OFFSHORE
WATERS. SEAS WILL BUILD A BIT MORE...PEAKING 3-5 FT NEARSHORE
WATERS WITH 4-6 FT OFFSHORE WATERS. A SMALL CRAFT ADVISORY WILL BE
ISSUED FOR THE GEORGIA OFFSHORE LEG...BEGINNING AT 6 PM THIS
EVENING AND REMAINING IN FORCE THROUGH THE NIGHT.
FRIDAY THROUGH MONDAY...MARGINAL SMALL CRAFT ADVISORY CONDITIONS
SHOULD LINGER IN OFFSHORE GEORGIA WATERS INTO EARLY FRIDAY...BEFORE
HIGH PRESSURE BECOMES MORE CENTERED OVER THE WESTERN ATLANTIC. WINDS
WILL THEN IMPROVE THROUGH THE WEEKEND AS THE PRESSURE GRADIENT
WEAKENS OVER THE COASTAL WATERS. SEAS WILL ALSO SUBSIDE THROUGH THE
WEEKEND...RANGING NO HIGHER THAN 2-4 FT. HIGHEST SEAS ARE EXPECTED
IN OFFSHORE GEORGIA WATERS.
&&
.TIDES/COASTAL FLOODING...
ONSHORE WINDS COMBINED WITH LUNAR INFLUENCES WILL HELP PUSH TIDE
LEVELS HIGHER THAN THE NORMAL ASTRONOMICAL TIDES THROUGH LATE
WEEK...POSSIBLY CAUSING SHALLOW COASTAL FLOODING LATER IN THE WEEK
DURING THE EVENING HIGH TIDES...MAINLY ALONG THE SOUTH CAROLINA
COAST SATURDAY AND SUNDAY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 11 AM EDT
FRIDAY FOR AMZ374.
&&
$$
ST/DPB
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
409 AM EDT THU MAY 14 2015
.SYNOPSIS...
HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH TONIGHT. THE
HIGH WILL GRADUALLY SHIFT OFFSHORE THIS WEEKEND INTO EARLY NEXT
WEEK. A COLD FRONT WILL PUSH THROUGH THE AREA NEXT TUESDAY OR
WEDNESDAY. HIGH PRESSURE WILL THEN RETURN BY THURSDAY.
&&
.NEAR TERM /THROUGH TODAY/...
THROUGH SUNRISE...SOME VERY SHALLOW GROUND FOG HAS DEVELOPED
ALONG PORTIONS OF THE GEORGIA COAST THIS MORNING. WEBCAMS AND
SURFACE OBSERVATIONS INDICATE THE FOG IS QUITE SHALLOW IN NATURE
AND SHOULD NOT SIGNIFICANTLY IMPACT TRAVEL THIS MORNING. THE FOG
COULD EXPAND NORTH ALONG THE LOWER SOUTH CAROLINA THROUGH SUNRISE.
TODAY...DEEP LAYERED HIGH PRESSURE WILL REMAIN IN TACT ACROSS THE
SOUTHEAST U.S. TODAY. HIGH RESOLUTION MODELS SUGGEST A NORTHEAST
WIND SURGE WORKING STEADILY DOWN THE NORTH CAROLINA COAST COULD
PROVIDE ENOUGH LOW-LEVEL CONVERGENCE TO SPREAD SOME ISOLATED
MARINE-BASED SHOWER ACTIVITY INLAND ACROSS PART OF UPPER
CHARLESTON AND EASTERN BERKELEY COUNTIES LATER THIS MORNING.
CONFIDENCE IS QUITE LOW IN THIS SCENARIO GIVEN HOW DRY THE LOWER
TROPOSPHERE IS ABOVE THE BOUNDARY LAYER SO WILL CARRY SOME VERY
LOW NON-ZERO POPS IN THIS AREA...BUT GENERALLY EXPECT DRY
CONDITIONS TO PREVAIL.
LOW-LEVEL MOISTURE RETURN WILL BEGIN TO SNEAK INTO THE FAR
SOUTHERN AND SOUTHWESTERN ZONES THIS AFTERNOON AS SURFACE HIGH
PRESSURE MOVES OFF THE MID-ATLANTIC COAST. FORECAST SOUNDINGS DO
NOT REALLY SUPPORT MUCH IN THE WAY OF MEANINGFUL INSTABILITY IN
THESE AREAS DESPITE THE SLOW EROSION OF THE CAPPING INVERSION.
WITH LITTLE/NO LOW-LEVEL CONVERGENCE EXPECTED ALONG THE PURE
/VERSUS RESULTANT/ SEA BREEZE CIRCULATION...POPS WILL BE KEPT
BELOW MENTIONABLE THRESHOLDS FOR NOW.
HIGHS WILL RANGE FROM THE LOWER 80S NORTH TO THE MID 80S CENTRAL
AND SOUTH...WARMEST ACROSS FAR INTERIOR SOUTHEAST GEORGIA. MID TO
UPPER 70S ARE LIKELY AT THE BEACHES WITH BREEZY ONSHORE WINDS.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
TONIGHT...LOW-LEVEL MOISTURE RETURN WILL CONTINUE THROUGH THE
NIGHT AS HIGH PRESSURE SHIFTS FARTHER OFFSHORE INTO THE WESTERN
ATLANTIC. MEAN MID-UPPER LEVEL RIDGING STILL LOOKS STRONG ENOUGH
TO PRECLUDE SHOWER ACTIVITY OVERNIGHT...BUT A BRIEF SPRINKLE OR
SHOWER CAN NOT BE COMPLETELY RULED OUT ACROSS SOUTHEAST GEORGIA
OVERNIGHT...MAINLY SOUTH OF THE I-16 CORRIDOR. WILL CONTINUE TO
HIGHLIGHT A DRY FORECAST FOR NOW GIVEN LOW CONFIDENCE IN ANY
MEASURABLE SHOWER ACTIVITY DEVELOPING. CLOUDS WILL THICKEN THROUGH
THE NIGHT WITH LOWS RANGING FROM THE LOWER 60S FAR NORTH TO THE
MID 60S ELSEWHERE.
SFC HIGH PRESSURE WILL BECOME CENTERED OVER THE WESTERN ATLANTIC BY
THE WEEKEND...SETTING UP EAST/SOUTHEAST FLOW THAT SLOWLY DEEPENS
MOISTURE OVER THE AREA AHEAD OF A SERIES OF SUBTLE H5 SHORTWAVES
THAT ROUND THE NORTHWEST FRINGE OF A MID LVL RIDGE CENTERED TO OUR
SOUTH. A SLIGHT CHANCE OF DIURNAL SHOWERS AND/OR THUNDERSTORMS WILL
BE POSSIBLE OVER INLAND PORTIONS OF SOUTHEAST GEORGIA ON FRIDAY AND
SATURDAY...FOLLOWED BY CHANCES OF AFTERNOON SHOWERS AND
THUNDERSTORMS ON SUNDAY...MAINLY AWAY FROM THE COAST WHERE LOW LVL
MOISTURE IS HIGHEST AND A SEABREEZE PROGRESSES INLAND. TEMPS SHOULD
BE A FEW DEGREES COOLER ON FRIDAY...IN THE UPPER 70S TO LOWER
80S...BUT A GRADUAL WARMING TREND IS ANTICIPATED THROUGH THE
WEEKEND. IN GENERAL...HIGH TEMPS SHOULD RANGE IN THE LOW TO MID 80S
ON SATURDAY...THEN MID TO UPPER 80S ON SUNDAY...WARMEST AWAY FROM
THE COAST.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
THE AREA WILL REMAIN ALONG THE WESTERN EDGE OF ATLANTIC HIGH
PRESSURE AND UNDER A LARGE MID LVL RIDGE EXTENDING NORTHWARD FROM
THE GULF OF MEXICO AND FLORIDA PENINSULA. THE PATTERN SHOULD RESULT
IN SOUTHERLY SFC FLOW INTO EARLY NEXT WEEK...ALLOWING MOISTURE TO
RETURN TO THE AREA WHILE WEAK H5 SHORTWAVES CONTINUE TO ROUND
NORTHWEST EDGE OF THE MID LVL RIDGE TO OUR SOUTH. CHANCES OF SHOWERS
AND/OR THUNDERSTORMS WILL BE POSSIBLE EACH AFTERNOON/EVENING INTO
EARLY NEXT WEEK...WITH HIGHEST COVERAGE INLAND. A COLD FRONT WILL
THEN APPROACH FROM THE NORTH/NORTHWEST ON TUESDAY BEFORE PUSHING
THROUGH THE AREA TUESDAY NIGHT INTO WEDNESDAY. HIGHER COVERAGE OF
SHOWERS AND THUNDERSTORMS CAN BE EXPECTED WITH COLD FROPA. HIGH
PRESSURE SHOULD THEN BUILD INTO THE AREA FROM THE NORTH/NORTHWEST
INTO THURSDAY.
TEMPS WILL BE ON A WARMING TREND NEXT WEEK...WITH MAX TEMPS REACHING
THE UPPER 80S TO LOWER 90S ON TUESDAY AHEAD OF THE APPROACHING COLD
FRONT. TEMPS SHOULD BE A FEW DEGREES COOLER ON WEDNESDAY AS HIGH
PRESSURE BUILDS BEHIND THE FRONT THROUGH THURSDAY. OVERNIGHT LOWS
SHOULD RANGE IN THE MID TO UPPER 60S AWAY FROM THE COAST.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR. EARLIER CONCERNS FOR IFR CIGS HAVE EASED A BIT BASED ON
LATEST HIGH RESOLUTION GUIDANCE. BOUNDARY LAYER JUST LOOKS TOO DRY
ABOVE THE SURFACE PER RAP FORECAST SOUNDINGS.
EXTENDED AVIATION OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PREVAIL
OUTSIDE SCATTERED DIURNAL CONVECTION LATE THIS WEEKEND AND EARLY
NEXT WEEK.
&&
.MARINE...
TODAY...A NORTHEAST WIND SURGE WILL OVERSPREAD THE WATERS TODAY
WITH DIRECTIONS SLOWLY VEERING TO THE EAST. WINDS LOOK TO GO NO
HIGHER THAN 15-20 KT FOR ALL LEGS WITH GUSTS HOLDING BELOW 25 KT.
SEAS WILL BUILD IN THE NORTHEAST FETCH...REACHING 3-5 FT NEARSHORE
WATERS AND A SOLID 5 FT FOR THE GEORGIA OFFSHORE WATERS BY LATE
THIS AFTERNOON. ATTM BOTH WINDS AND SEAS LOOK TO REMAIN BELOW
SMALL CRAFT ADVISORY LEVELS.
TONIGHT...MODEST ONSHORE WINDS WILL PERSIST...ALTHOUGH SPEEDS WILL
DIMINISH SOMEWHAT. WINDS ARE EXPECTED TO DROP TO 10-15 KT
NEARSHORE WATERS...BUT REMAIN 15-20 KT FOR THE GEORGIA OFFSHORE
WATERS. SEAS WILL BUILD A BIT MORE...PEAKING 3-5 FT NEARSHORE
WATERS WITH 4-6 FT OFFSHORE WATERS. A SMALL CRAFT ADVISORY WILL BE
ISSUED FOR THE GEORGIA OFFSHORE LEG...BEGINNING AT 6 PM THIS
EVENING AND REMAINING IN FORCE THROUGH THE NIGHT.
FRIDAY THROUGH MONDAY...MARGINAL SMALL CRAFT ADVISORY CONDITIONS
SHOULD LINGER IN OFFSHORE GEORGIA WATERS INTO EARLY FRIDAY...BEFORE
HIGH PRESSURE BECOMES MORE CENTERED OVER THE WESTERN ATLANTIC. WINDS
WILL THEN IMPROVE THROUGH THE WEEKEND AS THE PRESSURE GRADIENT
WEAKENS OVER THE COASTAL WATERS. SEAS WILL ALSO SUBSIDE THROUGH THE
WEEKEND...RANGING NO HIGHER THAN 2-4 FT. HIGHEST SEAS ARE EXPECTED
IN OFFSHORE GEORGIA WATERS.
&&
.TIDES/COASTAL FLOODING...
ONSHORE WINDS COMBINED WITH LUNAR INFLUENCES WILL HELP PUSH TIDE
LEVELS HIGHER THAN THE NORMAL ASTRONOMICAL TIDES THROUGH LATE
WEEK...POSSIBLY CAUSING SHALLOW COASTAL FLOODING LATER IN THE WEEK
DURING THE EVENING HIGH TIDES...MAINLY ALONG THE SOUTH CAROLINA
COAST SATURDAY AND SUNDAY.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 11 AM EDT
FRIDAY FOR AMZ374.
&&
$$
ST/DPB
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
130 AM EDT THU MAY 14 2015
.SYNOPSIS...
HIGH PRESSURE WILL BUILD FROM THE NORTH OVERNIGHT INTO LATE WEEK.
THE HIGH WILL GRADUALLY SHIFT OFFSHORE THIS WEEKEND INTO EARLY
NEXT WEEK. A WEAK COLD FRONT COULD PUSH THROUGH THE AREA NEXT TUESDAY
OR WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
MINOR ADJUSTMENTS FOR CURRENT TRENDS. NOT TOO KEAN ON FOG OR
STRATUS DEVELOPMENT GIVEN LATEST HIGH RESOLUTION DATA.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
MODELS IN GOOD AGREEMENT THAT HIGH PRESSURE RIDGING WILL PREVAIL
THIS PERIOD ALONG WITH LIMITED MOISTURE KEEPING RAIN CHANCES BELOW
NORMAL. HOWEVER...THAT DOES NOT MEAN IT WILL BE DRY EVERYWHERE THE
ENTIRE TIME...ESPECIALLY CLOSER TO THE ALTAMAHA RIVER WHERE THE BEST
MOISTURE AND INSTABILITY ARE EXPECTED. TEMPERATURES SHOULD BE NEAR
TO SLIGHTLY BELOW NORMAL...WITH THE WARMEST TEMPS ON SATURDAY.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE AREA WILL REMAIN ALONG THE WESTERN EDGE OF ATLANTIC HIGH
PRESSURE AND UNDER A LARGE MID LVL RIDGE EXTENDING NORTHWARD FROM
THE GULF OF MEXICO AND FLORIDA PENINSULA. THE PATTERN SHOULD RESULT
IN SOUTHERLY SFC FLOW INTO EARLY NEXT WEEK...ALLOWING MOISTURE TO
RETURN TO THE AREA WHILE NUMEROUS H5 SHORTWAVES ROUND THE
NORTH/NORTHWEST EDGE OF THE MID LVL RIDGE TO OUR SOUTH. CHANCES OF
SHOWERS AND/OR THUNDERSTORMS WILL BE POSSIBLE EACH AFTERNOON/EVENING
INTO EARLY NEXT WEEK...WITH HIGHEST COVERAGE INLAND. A WEAK COLD
FRONT COULD THEN APPROACH THE AREA FROM THE NORTH/NORTHWEST TUESDAY
AND/OR WEDNESDAY...LEADING TO HIGHER COVERAGE OF SHOWERS AND
THUNDERSTORMS OVER THE AREA. TEMPS WILL BE ON A WARMING TREND NEXT
WEEK...WITH MAX TEMPS REACHING THE UPPER 80S TO AROUND 90 AWAY FROM
THE COAST. TEMPS COULD BE A FEW DEGREES COOLER ON WEDNESDAY SHOULD
COLD FROPA OCCUR. OVERNIGHT LOWS SHOULD RANGE IN THE MID TO UPPER
60S AWAY FROM THE COAST.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR. EARLIER CONCERNS FOR IFR CIGS HAVE EASED A BIT BASED ON
LATEST HIGH RESOLUTION GUIDANCE. BOUNDARY LAYER JUST LOOKS TOO DRY
ABOVE THE SURFACE PER RAP FORECAST SOUNDINGS.
EXTENDED AVIATION OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PREVAIL
OUTSIDE SCATTERED DIURNAL CONVECTION LATE THIS WEEKEND AND EARLY
NEXT WEEK.
&&
.MARINE...
OVERNIGHT...A WEAK PRESSURE GRADIENT AND ONSHORE WINDS LESS THAN
15 KT WILL GIVE WAY TO HIGH PRESSURE BUILDING FROM THE
NORTH...TIGHTENING THE GRADIENT AND SUPPORTING A MODEST SURGE OF
NE WINDS AS HIGH AS 15-20 KT ACROSS SC WATERS LATE. EARLY SEAS OF
1-3 FT WILL BUILD TO 2-4 FT LATE...HIGHEST BEYOND 20 NM.
THURSDAY THROUGH SUNDAY...HIGH PRESSURE TO THE NORTH WILL SLOWLY
SHIFT OFFSHORE INTO THE ATLANTIC AND PERSIST THERE THROUGH THE
WEEKEND. THIS PATTERN WILL RESULT IN WINDS/SEAS THAT MOSTLY REMAIN
BELOW SMALL CRAFT ADVISORY LEVELS. HOWEVER...WHILE THE HIGH IS CLOSE
TO THE AREA THURSDAY...A TIGHT PRESSURE GRADIENT WILL EXIST OVER THE
AREA AND WE CANNOT RULE OUT SOME 25 KT GUSTS OVER THE NEAR SHORE
WATERS AND 6 FT SEAS BEYOND 20 NM INTO THURSDAY NIGHT.
&&
.TIDES/COASTAL FLOODING...
ONSHORE WINDS WILL HELP PUSH TIDE LEVELS HIGHER THAN THE NORMAL
ASTRONOMICAL TIDES THROUGH LATE WEEK...POSSIBLY CAUSING SHALLOW
COASTAL/SALT WATER FLOODING LATER IN THE WEEK DURING THE EVENING
HIGH TIDES...MAINLY ALONG THE SC COAST.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
ST
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
423 AM EDT THU MAY 14 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 329 AM EDT THU MAY 14 2015
WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO
EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL...
STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF
A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /TODAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS
MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH
CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM THE
MID 40S TO THE MID 50S.
THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE
DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER
TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE
CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI
VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO
VALLEY AHEAD OF IT.
EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE
DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE
INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE
SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD
LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT
CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT
SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL
CONTINUE WITH A DRY FORECAST TODAY.
TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE
TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS
GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 329 AM EDT THU MAY 14 2015
FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE
PERIOD.
UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A
WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL
LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS
SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES
ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE
OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN
HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH
TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED
BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST
SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED.
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING
ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED
CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST
UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40
POPS OVER THE ENTIRE FORECAST AREA.
REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND
POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO
VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN
ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE
INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP
OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND
LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS
AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND
SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT.
TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB
TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S
MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE
WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE
NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY
PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS
SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK.
WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER
SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES
INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS
SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY
FORECAST AFTER MONDAY.
&&
.AVIATION /DISCUSSION FOR THE 140900Z KIND TAF UPDATE/...
ISSUED AT 423 AM EDT THU MAY 14 2015
WILL VEER THE WIND FORECAST AND INCREASE THE SPEEDS SOME ON THE
UPDATE BASED ON CURRENT OBSERVATIONS.
PREVIOUS DISCUSSION FOLLOWS.
VFR THROUGH THE PERIOD.
EXPECT ONLY GRADUALLY INCREASING MID AND HIGH CLOUD THROUGH THE
PERIOD AS HIGH PRESSURE ALOFT AND AT THE SURFACE SLIDE EASTWARD.
WINDS WILL BE 10KT OR LESS THROUGHOUT THE PERIOD.
NO VISIBILITY ISSUES EXPECTED THROUGH THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...NIELD/JAS
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AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
329 AM EDT THU MAY 14 2015
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE
BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 329 AM EDT THU MAY 14 2015
WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO
EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL...
STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF
A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /TODAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS
MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH
CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM THE
MID 40S TO THE MID 50S.
THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE
DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER
TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE
CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI
VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO
VALLEY AHEAD OF IT.
EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE
DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE
INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE
SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD
LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT
CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT
SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL
CONTINUE WITH A DRY FORECAST TODAY.
TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE
TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS
GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 329 AM EDT THU MAY 14 2015
FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE
PERIOD.
UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A
WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL
LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS
SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES
ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE
OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN
HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH
TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED
BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST
SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED.
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING
ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED
CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST
UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40
POPS OVER THE ENTIRE FORECAST AREA.
REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND
POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO
VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN
ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE
INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP
OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND
LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS
AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND
SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT.
TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB
TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S
MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE
WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE
NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY
PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS
SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK.
WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER
SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES
INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS
SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY
FORECAST AFTER MONDAY.
&&
.AVIATION /DISCUSSION FOR THE 14/06Z TAFS/...
ISSUED AT 1230 AM EDT THU MAY 14 2015
VFR THROUGH THE PERIOD.
EXPECT ONLY GRADUALLY INCREASING MID AND HIGH CLOUD THROUGH THE
PERIOD AS HIGH PRESSURE ALOFT AND AT THE SURFACE SLIDE EASTWARD.
WINDS WILL BE 10KT OR LESS THROUGHOUT THE PERIOD.
NO VISIBILITY ISSUES EXPECTED THROUGH THE PERIOD.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...NIELD
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AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
332 AM CDT THU MAY 14 2015
.SYNOPSIS...
ISSUED AT 312 AM CDT THU MAY 14 2015
AS OF 2 AM...THE DRY AIRMASS OVER FAR EASTERN
MO...EASTERN IOWA AND ILLINOIS HAS HELD ITS GROUND AS THE LARGE
PLUME OF MOISTURE ADVECTION HEADS MAINLY NORTHWARD OVER THE WESTERN
2/3RDS OF IOWA AND THE MISSOURI RIVER VALLEY. THUS...WE HAVE
SITUATION WHERE LOCATIONS ARE SEEING VERY SLOW PROGRESS EAST OF THE
WIDESPREAD RAIN. WITH LOW LEVEL THROUGH 850MB WINDS REMAINING FROM
THE EAST TO SOUTHEAST THROUGH EARLY MORNING...THIS SLOW PROGRESSION
SHOULD CONTINUE TO BE SEEN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 312 AM CDT THU MAY 14 2015
TODAY AND TONIGHT... MODEL GUIDANCE ALL BRINGS THE
MOISTURE ADVECTION INTO THE HEART OF THE CWA DURING THE DAY
TODAY...WITH THE TIMING THE MAIN DIFFERENCES. THE ECMWF AND GFS ARE
BOTH QUICKER IN VEERING WINDS AT 850MB AROUND COMPARED TO THE SLOWER
NAM. MESOSCALE MODELS ARE A BIT SPLIT...WITH THE HRRR AND RAP
AGGRESSIVE IN VEERING MOISTURE INTO THE AREA...WHILE THE ARW AND NMM
ARE SLOWER...AND MUCH CLOSER TO THE NAM DEPICTION. THIS DIFFERENCE
IS MAKING A CHALLENGING CALL..SINCE ALL ARE INITIALIZING RATHER
WELL WITH MEASURABLE RAINS IN IOWA MAINLY WEST OF I-35 THROUGH 06Z.
HOWEVER...LOOKING AT OUR RADAR...THERE ARE ALREADY SHOWERS AT LEAST
ALOFT...IF NOT HITTING THE GROUND AS FAR EAST AS A VINTON TO KEOKUK
LINE. THAT SUPPORTS MOISTURE TRANSPORT BEING WELL EAST OF THE MORE
CONSERVATIVE SOLUTIONS...AND WILL PLAY A POP FORECAST MORE CLOSELY
TO THE ECMWF TODAY. EXPECT CLOUDY SKIES THROUGHOUT...WITH LITTLE
HEATING WEST ALL DAY...WHILE EAST HAS A DRY MORNING...AND MODEST
TEMPERATURE RECOVERY TO THE MID 60S. WILL SPREAD CATEGORICAL POPS
EAST TO AROUND MANCHESTER TO BURLINGTON BY MID MORNING...THEN SHIFT
LIKELY POPS EAST OVER THE REST OF THE CWA THIS AFTERNOON. THIS MAY
NEED A CATEGORICAL SHIFT UPWARDS AS WELL...BUT WILL GIVE A 10
PERCENT NOD TO THE SLOWER SOLUTIONS HERE...AND KEEP IT LIKELY.
TONIGHT...THE GLOBAL MODELS STRONGLY SUGGEST AN UPTICK IN CONVECTIVE
POTENTIAL OVER THE NORTHERN 2/3RDS OF THE CWA THIS EVENING. IN
FACT...THEY SUGGEST A WEAK MCS OF SORTS...BUT THE NAM AND OTHER
MESOMODELS SUGGEST THIS ACTIVITY FARTHER SOUTH. I AM DOUBTFUL OF
BUILDING ANY SURFACE BASED CAPE ANYWHERE IN ILLINOIS TODAY...SO THE
NORTHERN SOLUTIONS ARE MORE LIKELY SINCE THE VORTICITY CENTER
PASSING OVER THAT REGION SHOULD SUPPORT AN EVENING ROUND OF LIFT.
MUCAPE SHOULD BE LIMITED TO THE SOUTH HALF AND ONLY BE 500 TO 700
PER THE GFS SOLUTIONS...THUS WILL KEEP THUNDER LIMITED TO THAT
PORTION OF THE AREA TONIGHT. BY 06Z...ALL MODELS SHOW THE LLJ
VEERING EAST...WITH THE VORT PASSING INTO WISCONSIN BY THEN...THUS
COVERAGE SHOULD BECOME FAR MORE ISOLATED AFTER THAT TIME. LOWS
TONIGHT...WITH MUCH HIGHER DEWPOINTS IN PLACE THAN THIS
MORNING...WILL MAINLY BE IN THE MID 50S NORTH TO AROUND 60 SOUTH.
ERVIN
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 312 AM CDT THU MAY 14 2015
FRIDAY...UPPER-LEVEL WINDS WILL BE VERY LIGHT AS RIDGING BUILDS IN
BEHIND A SHORTWAVE OVER THE UPPER GREAT LAKES AND AHEAD OF A
LONGWAVE TROUGH AND CLOSED UPPER LOW OVER THE WESTERN U.S.
THE MOST NOTICEABLE SENSIBLE WEATHER ON FRIDAY WILL BE AN
INCREASINGLY HUMID AIRMASS AS SFC DEWPOINTS RISE INTO THE 60S
THANKS TO S/SW WINDS. THE MOIST ATMOSPHERE COUPLED WITH HIGHS IN
THE MID 70S TO LOWER 80S WILL YIELD MUCH GREATER INSTABILITY
COMPARED TO THE PAST SEVERAL DAYS. MUCAPE VALUES OF 1500-2500
J/KG ARE LIKELY. THEREFORE ANY STORM THAT FORMS COULD BE BRIEFLY
STRONG OR SEVERE...ALTHOUGH LACK OF SUFFICIENT VERTICAL SPEED
SHEAR WOULD INHIBIT ANYTHING PROLONGED OR WIDESPREAD.
CONVECTIVE COVERAGE...IT LOOKS ISOLATED TO SCATTERED AT BEST.
THERE DOES NOT LOOK TO BE MUCH IN THE WAY OF FORCING FOR ASCENT
DURING THE DAY AND FORECAST SOUNDINGS DO HAVE A LITTLE SBCIN.
HOWEVER...THE MODELS ARE SHOWING AN UPTICK IN COVERAGE FRIDAY
NIGHT WHEN A SUBTLE 500MB VORTICITY EMBEDDED IN THE SW MID-LEVEL
FLOW MAY TRAVERSE E IOWA/W ILLINOIS. ADDITIONALLY...SOME WEAK
850MB CONVERGENCE IS FORECAST ON THE NOSE OF A SLIGHTLY STRONGER
WIND FIELD OVER SOUTH-CENTRAL IOWA INTO NW MISSOURI.
SATURDAY...HUMID WEATHER CONTINUES ALONG WITH A SCATTERED
THUNDERSTORM THREAT. NEGLIGIBLE FORCING FOR ASCENT...BUT DAYTIME
HEATING MAY BE ENOUGH TO SET OFF SCATTERED SHOWERS AND
STORMS...ESPECIALLY DURING THE AFTN/EVENING. CONDITIONAL
INSTABILITY IS FORECAST TO BE NEAR OR SLIGHTLY HIGHER THAN ON
FRIDAY. 0-6 KM BULK SHEAR MAY PEAK NEAR 30 KTS SO A LITTLE HIGHER
THAN FRIDAY AS WELL.
SPC HAS OUTLOOKED THE EXTREME WESTERN PORTION OF THE DVN
CWA IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS. STORMS THAT FORM
IN THIS ENVIRONMENT HAVE THE POTENTIAL TO PRODUCE HAIL AND WIND
GUSTS AT SEVERE LEVELS BUT IF ANYTHING DOES OCCUR IT WILL BE
ISOLATED.
FOR FRIDAY AND SATURDAY ANY STORMS THAT FORM WILL MOVE
SLOWLY...GENERALLY FROM SW TO NE AT LESS THAN 30 MPH...AND POSE A
THREAT FOR LOCALIZED HEAVY RAINFALL VIA FORECAST STORM MOTION
VECTORS AND PWAT VALUES NEAR 1.50 INCHES.
SUNDAY...THERE IS A RISK FOR STRONG AND SEVERE STORMS ACROSS THE
FORECAST AREA. MODEL GUIDANCE IS SHOWING OVERLAP OF HIGHER
INSTABILITY AND SHEAR IN ADVANCE OF AN APPROACHING COLD FRONT. RIGHT
NOW BEST SYNOPTIC DYNAMICS PASS OVER WESTERN IOWA INTO MINNESOTA AS
DOES THE SFC LOW...SO STORM COVERAGE ACROSS THE DVN CWA MAY NOT BE
THAT WIDESPREAD AND MAY BE MOSTLY ANCHORED TO THE VICINITY OF THE
SFC COLD FRONT.
MONDAY THROUGH WEDNESDAY...BOTH THE GFS AND ECMWF ADVECT A MUCH
DRIER AIRMASS INTO THE UPPER MIDWEST AS A SPRAWLING HIGH PRESSURE
SYSTEM DROPS OUT OF CANADA INTO THE NORTHERN U.S. THREAT FOR
MEASURABLE RAIN IS QUITE LOW AT THIS POINT SO SHOULD BE A PLEASANT
PERIOD WITH HIGHS IN THE 60S AND LOWS IN THE 40S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1149 PM CDT WED MAY 13 2015
VFR CONDITIONS WILL CONTINUE 15Z/14 AS CIGS SLOWLY LOWER DUE TO AN
APPROACHING STORM SYSTEM FROM THE PLAINS. AFT 15Z/14 CONDITIONS
WILL SLOWLY DETERIORATE TO MVFR THROUGH 00Z/15. AFT 00Z/15 THERE
IS A SMALL POSSIBILITY OF IFR CIGS DEVELOPING. HOWEVER...THIS
POSSIBILITY WAS NOT INCLUDED IN THE 06Z TAFS DUE TO UNCERTAINTY ON
HOW LOW CLOUD HEIGHTS WILL GET.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...UTTECH
AVIATION...08
AREA FORECAST DISCUSSION
NWS HASTINGS NE
420 AM CDT THU MAY 14 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT THU MAY 14 2015
ALTHOUGH THESE FIRST 24 HOURS CERTAINLY DO NOT FEATURE THE
POTENTIALLY "HIGHER IMPACT" THREAT OF SEVERE THUNDERSTORMS FOR
FRIDAY-SATURDAY AS DESCRIBED IN THE LONG TERM SECTION
BELOW...TODAY AND TONIGHT COME WITH THEIR OWN SET OF
CHALLENGES...NAMELY: 1) TIMING THE END OF RAIN/DRIZZLE THIS
MORNING...2) TIMING HOW QUICKLY/SLOWLY WIDESPREAD CLOUDS DEPART
FROM WEST-EAST TODAY AND RESULTANT IMPACT ON HIGH TEMPS...AND 3)
TRYING TO DETERMINE HOW MUCH THUNDERSTORM DEVELOPMENT/COVERAGE
OCCURS LATE TONIGHT AND WHETHER A FEW OF THESE STORMS COULD
ACTUALLY BE STRONG TO MARGINALLY SEVERE (DESPITE THE LACK OF AN
OFFICIAL SPC MARGINAL RISK AREA ON THE LATEST DAY 1 OUTLOOK).
STARTING OFF WITH THE PRESENT SCENE AS OF 08Z/3AM THIS
MORNING...WE ARE IN THE LATTER STAGES OF A REMARKABLY
BENEFICIAL...LARGELY STRATIFORM (NON-CONVECTIVE/THUNDERSTORM)
WIDESPREAD RAIN EVENT THAT HAS BEEN GOING ON SINCE LATE WED
AFTERNOON/EARLY EVENING. AS OF THIS WRITING...RAIN IS STARTING TO
STEADILY WIND DOWN/BECOME MORE SPOTTY WITHIN THE WESTERN HALF OF
THE CWA...WHILE CONTINUING STEADY IN EASTERN COUNTIES. PER SEVERAL
AUTOMATED AIRPORT GAUGES AND RADAR ESTIMATION...IT APPEARS LIKELY
THAT THE MAJORITY OF THE CWA IS GOING TO END UP WITH A SOLID
0.50-1.00" BEFORE RAIN COMPLETELY ENDS THIS MORNING...CERTAINLY A
WELCOMED EVENT FOR THE MOST PART. THIS LARGE SHIELD OF MAINLY
LIGHT RAIN IS BEING DRIVEN IN THE MID-UPPER LEVELS BY A SLIGHTLY
NEGATIVELY TILTED SHORTWAVE TROUGH CURRENTLY PASSING DIRECTLY
THROUGH THE HEART OF THE CENTRAL PLAINS. WHILE A SMALL ZONE OF
SHORTWAVE RIDGING IS MOVING IN BEHIND THIS WAVE...THE CENTER OF
THE NEXT SIGNIFICANT UPPER LEVEL SYSTEM IS SLOWLY BUT SURELY
APPROACHING THE PACIFIC COAST. AT THE SURFACE EARLY THIS
MORNING...WEAK LOW PRESSURE CENTERED TO THE WEST IS PROMOTING
FAIRLY UNIFORM SOUTHEAST BREEZES GENERALLY 7-13 MPH IN MOST AREAS.
LOW TEMPS APPEAR ON TRACK TO BOTTOM OUT IN THE 51-54 RANGE IN
MOST PLACES.
NOW LOOKING AHEAD FORECAST-WISE...
EARLY THIS MORNING (THROUGH 12Z/7AM): CERTAINLY THE MAIN ISSUE IS
THE CONTINUING GRADUAL DECREASE IN THE COVERAGE OF MEASURABLE
RAIN...AS THE OVERALL AREA OF RAIN SLOWLY ENDS FROM PRIMARILY
WEST-TO-EAST AS INDIVIDUAL RAIN ELEMENTS STREAM FROM SOUTH-TO-
NORTH. WILL OBVIOUSLY BE CARRYING SOME PRETTY HEFTY EARLY MORNING
POPS IN EASTERN ZONES AND MUCH LOWER VALUES FAR WEST.
HOWEVER...GIVEN THE PRESENCE OF WIDESPREAD LOW STRATUS EVEN IN
AREAS WHERE MEASURABLE RAIN IS ENDING...COULD CERTAINLY SEE SOME
MAINLY NON-MEASURABLE LIGHT DRIZZLE SHOW ITS HAND AS WELL...SO
HAVE INCLUDED THIS MENTION IN WESTERN AREAS WHERE THE MEASURABLE
POP IS BELOW 20 PERCENT. WOULD NORMALLY A BIT MORE CONCERNED ABOUT
POTENTIALLY IMPACTFUL FOG DEVELOPING IN AREAS WHERE RAIN IS
ENDING...BUT WITH THE WIDESPREAD LOW STRATUS FIRMLY IN PLACE AND
LIGHT-BUT-STEADY BREEZES AM GOING TO HOLD OFF ON A FORMAL FOG
MENTION FOR NOW AND MONITOR TRENDS TO MAKE SURE AUTOMATED SITES DO
NOT START DROPPING BELOW 1 MILE...WHICH WOULD CERTAINLY JUSTIFY A
LAST-MINUTE FOG INCLUSION SHOULD THIS START OCCURRING.
TODAY (7AM-7PM): BY THE TIME 12Z/7AM ROLLS AROUND IN A FEW
HOURS...ANY LINGERING AREAS OF LIGHT MEASURABLE RAIN SHOULD
LARGELY BE CONFINED TO THE EASTERN HALF OF THE CWA...BUT EVEN THIS
SHOULD BE STEADILY PUSHING OUT WITH TIME...LEAVING ONLY A FEW
HOURS OF LIGHT DRIZZLE POTENTIAL IN ITS WAKE. WILL OBVIOUSLY
UPDATE AGAIN BEFORE SUNRISE BASED ON RADAR TRENDS...BUT FOR NOW WILL
CARRY ONLY A FEW HOURS OF LIKELY POPS IN EASTERN ZONES BEFORE
DROPPING DOWN TO ONLY SLIGHT 20 POPS IN EXTREME EASTERN COUNTIES
ALONG HWY 81 BY LATE MORNING (AGAIN THOUGH...SPOTTY DRIZZLE COULD
EXTEND BACK TO THE TRI-CITIES AREA WELL-PAST SUNRISE). ONCE
RAIN/DRIZZLE FINALLY ENDS...THE BIG QUESTION IS HOW QUICKLY/SLOWLY
DO CLOUDS VACATE FROM WEST-TO-EAST...AS THE MID LEVEL SHORTWAVE
TROUGH LIFTS AWAY FROM THE AREA INTO IA/MN...PROVIDING A BRIEF
PERIOD OF SHORTWAVE RIDGING FOR THIS AFTERNOON/EVENING. IF
ANYTHING...HAVE SLIGHTLY SLOWED DOWN THE CLEARING TREND FROM
PREVIOUS FORECAST...BUT AM COUNTING ON LIGHT WESTERLY LOW-LEVEL
FLOW TO GRADUALLY SCOUR OUT LOW STRATUS (OR AT LEAST TURN IT INTO
A SCATTERED COVERAGE) AS THE DAY WEARS ON. THAT BEING SAID...SOME
OF THE LATEST TRENDS IN 900-850MB RELATIVE HUMIDITY ALONG WITH SKY
COVER PROGS FROM THE LATEST HRRR SUGGEST THAT COUNTIES EAST OF
HIGHWAY 281 COULD HANG ONTO CONSIDERABLE CLOUD COVER WELL INTO THE
AFTERNOON WITH ANY APPRECIABLE CLEARING COMING LATE IN THE DAY.
THE BOTTOM LINE IS THAT ALTHOUGH CONFIDENCE IS NOT
OVERLY-HIGH...EXPECT SKY COVER TODAY IN THE WESTERN 1/2 OF THE
CWA TO IMPROVE FROM CLOUDY TO PARTLY CLOUDY/MOSTLY SUNNY...WHILE
THE EASTERN HALF ONLY IMPROVES FROM CLOUDY TO MOSTLY CLOUDY/PARTLY
CLOUDY. OBVIOUSLY THE CLOUD TRENDS WILL HAVE A DECENT IMPLICATION
ON HIGH TEMPERATURES THIS AFTERNOON. ALTHOUGH DID NOT FOLLOW
IT OUTRIGHT...DID TREND HIGHS TOWARD THE LATEST RAP13
NUMBERS...WHICH LOWERED VALUES GENERALLY 3-4 DEGREES IN MOST
CENTRAL/EASTERN COUNTIES...WHILE LEAVING WESTERN ZONES FAIRLY
SIMILAR TO PREVIOUS FORECAST. THE NET RESULT AIMS FROM NEAR-70 FAR
EAST...LOW-MID 70S TRI-CITIES AREA...AND UPPER 70S/LOW 80S FAR
WEST/SOUTHWEST. AS FOR WINDS TODAY...INITIALLY SOUTH/SOUTHEAST
BREEZES THIS MORNING WILL STEADILY MORE SOUTHWESTERLY IF NOT
WESTERLY AS THE DAY WEARS ON...BUT WITH SUSTAINED SPEEDS NOT
EXPECTED TO AVERAGE MORE THAN 10-15 MPH.
THIS EVENING/TONIGHT (7PM-7AM): IN SHORT...EXPECT A FAIRLY
TRANQUIL EVENING FOLLOWED BY A SOMEWHAT MORE ACTIVE LATE NIGHT
PERIOD WITH POTENTIALLY A FEW STRONG STORMS...ALTHOUGH CONFIDENCE
IS STILL A BIT LOW ON WHETHER THUNDERSTORM DEVELOPMENT WILL BE
MORE ISOLATED OR MORE WIDESPREAD. AS A RESULT...HAVE KEPT ALL
POST-MIDNIGHT POPS CAPPED AT NO HIGHER THAN 30-50 PERCENT FOR
NOW...AND WITH THE HIGHEST VALUES LARGELY FOCUSED OVER THE WESTERN
1/2 OF THE CWA. LOOKING ALOFT TO THE MID-UPPER LEVELS...A BRIEF
PERIOD OF SHORTWAVE RIDGING THIS EVENING WILL QUICKLY GIVE WAY TO
A LOW AMPLITUDE DISTURBANCE MOVING INTO THE CENTRAL PLAINS IN
SOUTHWEST FLOW ALOFT...ALONG THE VERY LEADING EASTERN EDGE OF THE
MAIN WESTERN CONUS TROUGH. ALTHOUGH THERE ARE THE TYPICAL VARIOUS
DEPICTIONS OF HOW CONVECTION WILL PLAY OUT TONIGHT AMONGST THE
VARIOUS DETERMINISTIC AND HIGHER-RES MODELS...GENERALLY TEND TO
PREFER THE DEPICTION OF THE 00Z NSSL 4KM-WRF AT THIS TIME. THIS
MEANS REASONABLY HIGH CONFIDENCE IN A DRY EVENING (PRE-
MIDNIGHT)...ALTHOUGH CONVECTION COULD ALREADY BE APPROACHING THE
CWA FROM SOUTHWEST NEB/SOUTHWEST KS AS IT FIRES UP ALONG THE NOSE
OF AN INCREASING 30-40KT LOW LEVEL JET EVIDENT AT 850MB. THEN
POST-MIDNIGHT...EXPECT ISOLATED TO SCATTERED SHOWERS/STORMS TO
MOVE INTO AND/OR DEVELOP DIRECTLY OVER THE CWA AS THE MID LEVEL
WAVE AND ASSOCIATED LOW LEVEL JET FORCING SPREADS FARTHER EAST.
COULD SEE A MORE CONCENTRATED ZONE OF CONVECTION THAT COULD
EVENTUALLY NECESSITATE LIKELY POPS...BUT JUST TOO TOUGH TO TELL
WHERE EXACTLY THIS WOULD BE YET. THAT BEING SAID...ALTHOUGH STORMS
WILL BE POSSIBLE ALMOST ANYWHERE BETWEEN MIDNIGHT-SUNRISE...THE
WESTERN HALF OF THE CWA SHOULD BE MOST FAVORED. AS FOR STORM
INTENSITY...THAT WILL OBVIOUSLY DEPEND HEAVILY ON THE DEGREE OF
ELEVATED INSTABILITY. AS IS COMMON...THE LATEST 06Z NAM SEEMS A
BIT HIGH WITH 850-700MB LAYER CAPE POTENTIALLY EXCEEDING 2500
J/KG...WHILE THE GFS LOOKS A BIT MORE REALISTIC BUT STILL HAS
ELEVATED CAPE INCREASING TO AROUND 1000 J/KG. ALTHOUGH DEEP LAYER
SHEAR IS PROGGED TO REMAIN FAIRLY WEAK AT ONLY AROUND 20-25KT AT
MOST...THIS INSTABILITY (ESPECIALLY IF THE NAM IS REMOTELY
CORRECT) COULD EASILY SUPPORT A FEW STRONG TO MARGINALLY SEVERE
HAIL CORES AT LEAST IN THE NICKEL-QUARTER RANGE. IN ORDER TO
REMAIN REASONABLY CONSISTENT WITH THE LACK OF AN OFFICIAL MARGINAL
RISK AREA ON THE INITIAL SPC DAY 1 OUTLOOK...WILL KEEP A FORMAL
SEVERE STORM MENTION OUT OF THE HAZARDOUS WEATHER OUTLOOK FOR
NOW...BUT WILL INTRODUCE A MENTION OF LATE-NIGHT STRONG STORM
POTENTIAL TO GET THE BALL TRENDING THAT DIRECTION. TURNING TO
OTHER ELEMENTS...BREEZES TONIGHT SHOULD GENERALLY AVERAGE 5-10 MPH
FROM THE SOUTHEAST AS A WEAK COLD FRONT STALLS OUT JUST NORTH OF
THE CWA THIS EVENING AND LOW PRESSURE DEVELOPS WEST. MADE VERY
LITTLE CHANGE TO LOW TEMPS...AIMING MOST OF THE CWA BETWEEN 57-61
DEGREES. ON ONE LAST NOTE...THE PRESENCE OF FAIRLY LIGHT SOUTHEAST
BREEZES LATE TONIGHT...AND FAIRLY CLOSE SURFACE TEMP/DEWPOINT
DEPRESSIONS ARGUE THAT FOG COULD POSSIBLY BECOME AN ISSUE IN SOME
AREAS...AND THIS HAS MODEST SUPPORT IN THE LATEST SREF VISIBILITY
PROGS. HOWEVER...GIVEN THAT CONFIDENCE IN IMPACTFUL FOG (GENERALLY
1 MILE VISIBILITY OR LESS) ISN/T EVEN THAT HIGH FOR THIS
MORNING...IT/S HARD TO PUT MUCH FAITH IN TRENDS FOR 24 HOURS FROM
NOW...SO WILL KEEP IT OUT OF THE FORECAST FOR NOW AND LET THE
FOCUS REMAIN ON THE THUNDERSTORM CHANCES.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 420 AM CDT THU MAY 14 2015
A FAIRLY ACTIVE WEATHER PATTERN IS EXPECTED THROUGH THE EXTENDED
PERIODS WITH SEVERAL CHANCES FOR SHOWERS AND THUNDERSTORMS AS THE
LOCAL AREA WILL BE INFLUENCED BY MULTIPLE UPPER LEVEL DISTURBANCES
TRACKING OUT OF THE DESERT SOUTHWEST AND INTO THE PLAINS.
OVERALL...TEMPERATURES WILL BE VERY MILD TO START THE
PERIOD...WITH A COLD FRONT DROPPING DOWN ACROSS THE LOCAL AREA
SUNDAY NIGHT/MONDAY...WHICH WILL RESULT IN TEMPERATURES DIPPING
BELOW NORMAL FOR THE FIRST HALF OF NEXT WEEK.
STARTING OFF FRIDAY MORNING...THE LOCAL AREA WILL LIKELY HAVE
ONGOING CONVECTION AS THE LLJ WILL BE POINTED TOWARDS THE LOCAL
AREA AND AN UPPER LEVEL DISTURBANCE IN SOUTHERLY FLOW ADVECTS
ACROSS THE LOCAL AREA. AS THIS CONVECTION TRACKS NORTH THROUGH THE
MORNING HOURS...THE POTENTIAL FOR REDEVELOPMENT IN THE WARM
SECTOR LOOKS FAVORABLE AS DEWPOINTS ARE FORECAST TO CLIMB TO NEAR
60...WHICH SHOULD HELP INSTABILITY VALUES TO SOAR ACROSS THE LOCAL
AREA. THESE INSTABILITY VALUES...COMBINED WITH AMPLE LOW LEVEL
SHEAR...SHOULD RESULT IN ORGANIZED CONVECTION DEVELOPING BY LATE
AFTERNOON...WITH MOST OF SOUTH CENTRAL NEBRASKA IN THE ENHANCED
RISK FOR SEVERE WEATHER ISSUED BY SPC. IF THUNDERSTORMS DO
DEVELOP...EXPECT THE POTENTIAL FOR LARGE HAIL...DAMAGING WIND
GUSTS AS WELL AS ISOLATED TORNADOES UNDER THIS SCENARIO.
AS THE LONGWAVE TROUGH THEN CROSSES THE ROCKIES ON SATURDAY...
EXPECT MULTIPLE UPPER LEVEL DISTURBANCES ROUNDING THE BASE OF THE
LONGWAVE TROUGH TO HELP TRIGGER ADDITIONAL CONVECTION ACROSS THE
LOCAL AREA. ONCE AGAIN...WITH ELEVATED DEWPOINTS ALONG WITH GOOD
CAPE VALUES AND MODEST SHEAR...EXPECT THE POTENTIAL FOR SEVERE
THUNDERSTORMS TO ONCE AGAIN BE POSSIBLE SATURDAY
AFTERNOON/EVENING...WITH JUST ABOUT THE ENTIRE FORECAST AREA NOW
HIGHLIGHTED FOR AN ENHANCED RISK OF SEVERE WEATHER.
CHANCES FOR CONVECTION WILL THEN CONTINUE INTO SUNDAY...WHEN AN
APPROACHING COLD FRONT SHOULD PUT AN END TO THIS MORE SIGNIFICANT
WEATHER...WITH COOLER AND MORE STABLE AIR ANTICIPATED IN ITS WAKE
TO START THE WORK WEEK. WHILE SHORTWAVE RIDGING ALOFT IS ALSO
FAVORED TO START THE WORK WEEK...YET ANOTHER UPPER LEVEL
DISTURBANCE IS FORECAST TO LIFT OUT OF THE SOUTHWEST AS EARLY AS
TUESDAY AFTERNOON...WHICH SHOULD BRING ADDITIONAL CHANCES FOR
SHOWERS AND THUNDERSTORMS ACROSS THE LOCAL AREA. WITH LESS
INSTABILITY TO WORK WITH...EXPECT THUNDERSTORM ACTIVITY FOR MID
WEEK TO BE MORE ISOLATED ACROSS THE REGION.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 100 AM CDT THU MAY 14 2015
OVERALL NO MAJOR CHANGES FROM PREVIOUS 00Z PACKAGE...AS A
COMBINATION OF MVFR/IFR CONDITIONS ARE EXPECTED TO DOMINATE AT
LEAST THE FIRST HALF OF THE PERIOD...AND POSSIBLY A FEW HOURS
BEYOND...WITH VFR CEILING/VISIBILITY THEN RETURNING FROM ROUGHLY
MID-AFTERNOON ONWARD. WHILE THIS GENERAL TREND CARRIES FAIRLY HIGH
CONFIDENCE...THERE ARE PLENTY OF QUESTION MARKS ESPECIALLY WITH
REGARD TO VISIBILITY...AND WHETHER OR NOT AT LEAST A BRIEF PERIOD
OF MORE SUBSTANTIAL FOG COULD SET IN BEHIND THE RAIN SHIELD THIS
MORNING...BUT FOR NOW HAVE NOT GONE TOO PESSIMISTIC DOWN THIS
ROAD. SPEAKING OF RAIN...AT LEAST THROUGH THESE FIRST 5-6 HOURS
OR SO...A FAIRLY STEADY LIGHT RAIN WILL PERSIST AT BOTH TERMINALS
BEFORE POSSIBLY TRANSITIONING TO A FEW HOURS OF LIGHT DRIZZLE
BEFORE PRECIP ENDS COMPLETELY. WILL AIM FOR A RETURN TO PREVAILING
VFR VISIBILITY BY MID-LATE MORNING...BUT WILL HOLD ONTO AN MVFR
CEILING INTO MID-AFTERNOON BEFORE SCATTERING OUT/LIFTING TO VFR
LEVELS. CONFIDENCE IS FAIRLY HIGH IN VFR CONDITIONS FOR THE LATTER
SEVERAL HOURS OF THE PERIOD THURSDAY EVENING. THERE IS AN OUTSIDE
CHANCE THAT ISOLATED SHOWERS/THUNDERSTORMS COULD BE STARTING TO
DEVELOP IN THE GENERAL AREA TOWARD THE VERY END OF THE
PERIOD...BUT THIS SEEMS MORE LIKELY DURING THE FOLLOWING 6 HOURS
SO WILL HOLD OFF ON ANY MENTION FOR NOW.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...ROSSI
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS HASTINGS NE
359 AM CDT THU MAY 14 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT THU MAY 14 2015
ALTHOUGH THESE FIRST 24 HOURS CERTAINLY DO NOT FEATURE THE
POTENTIALLY "HIGHER IMPACT" THREAT OF SEVERE THUNDERSTORMS FOR
FRIDAY-SATURDAY AS DESCRIBED IN THE LONG TERM SECTION
BELOW...TODAY AND TONIGHT COME WITH THEIR OWN SET OF
CHALLENGES...NAMELY: 1) TIMING THE END OF RAIN/DRIZZLE THIS
MORNING...2) TIMING HOW QUICKLY/SLOWLY WIDESPREAD CLOUDS DEPART
FROM WEST-EAST TODAY AND RESULTANT IMPACT ON HIGH TEMPS...AND 3)
TRYING TO DETERMINE HOW MUCH THUNDERSTORM DEVELOPMENT/COVERAGE
OCCURS LATE TONIGHT AND WHETHER A FEW OF THESE STORMS COULD
ACTUALLY BE STRONG TO MARGINALLY SEVERE (DESPITE THE LACK OF AN
OFFICIAL SPC MARGINAL RISK AREA ON THE LATEST DAY 1 OUTLOOK).
STARTING OFF WITH THE PRESENT SCENE AS OF 08Z/3AM THIS
MORNING...WE ARE IN THE LATTER STAGES OF A REMARKABLY
BENEFICIAL...LARGELY STRATIFORM (NON-CONVECTIVE/THUNDERSTORM)
WIDESPREAD RAIN EVENT THAT HAS BEEN GOING ON SINCE LATE WED
AFTERNOON/EARLY EVENING. AS OF THIS WRITING...RAIN IS STARTING TO
STEADILY WIND DOWN/BECOME MORE SPOTTY WITHIN THE WESTERN HALF OF
THE CWA...WHILE CONTINUING STEADY IN EASTERN COUNTIES. PER SEVERAL
AUTOMATED AIRPORT GAUGES AND RADAR ESTIMATION...IT APPEARS LIKELY
THAT THE MAJORITY OF THE CWA IS GOING TO END UP WITH A SOLID
0.50-1.00" BEFORE RAIN COMPLETELY ENDS THIS MORNING...CERTAINLY A
WELCOMED EVENT FOR THE MOST PART. THIS LARGE SHIELD OF MAINLY
LIGHT RAIN IS BEING DRIVEN IN THE MID-UPPER LEVELS BY A SLIGHTLY
NEGATIVELY TILTED SHORTWAVE TROUGH CURRENTLY PASSING DIRECTLY
THROUGH THE HEART OF THE CENTRAL PLAINS. WHILE A SMALL ZONE OF
SHORTWAVE RIDGING IS MOVING IN BEHIND THIS WAVE...THE CENTER OF
THE NEXT SIGNIFICANT UPPER LEVEL SYSTEM IS SLOWLY BUT SURELY
APPROACHING THE PACIFIC COAST. AT THE SURFACE EARLY THIS
MORNING...WEAK LOW PRESSURE CENTERED TO THE WEST IS PROMOTING
FAIRLY UNIFORM SOUTHEAST BREEZES GENERALLY 7-13 MPH IN MOST AREAS.
LOW TEMPS APPEAR ON TRACK TO BOTTOM OUT IN THE 51-54 RANGE IN
MOST PLACES.
NOW LOOKING AHEAD FORECAST-WISE...
EARLY THIS MORNING (THROUGH 12Z/7AM): CERTAINLY THE MAIN ISSUE IS
THE CONTINUING GRADUAL DECREASE IN THE COVERAGE OF MEASURABLE
RAIN...AS THE OVERALL AREA OF RAIN SLOWLY ENDS FROM PRIMARILY
WEST-TO-EAST AS INDIVIDUAL RAIN ELEMENTS STREAM FROM SOUTH-TO-
NORTH. WILL OBVIOUSLY BE CARRYING SOME PRETTY HEFTY EARLY MORNING
POPS IN EASTERN ZONES AND MUCH LOWER VALUES FAR WEST.
HOWEVER...GIVEN THE PRESENCE OF WIDESPREAD LOW STRATUS EVEN IN
AREAS WHERE MEASURABLE RAIN IS ENDING...COULD CERTAINLY SEE SOME
MAINLY NON-MEASURABLE LIGHT DRIZZLE SHOW ITS HAND AS WELL...SO
HAVE INCLUDED THIS MENTION IN WESTERN AREAS WHERE THE MEASURABLE
POP IS BELOW 20 PERCENT. WOULD NORMALLY A BIT MORE CONCERNED ABOUT
POTENTIALLY IMPACTFUL FOG DEVELOPING IN AREAS WHERE RAIN IS
ENDING...BUT WITH THE WIDESPREAD LOW STRATUS FIRMLY IN PLACE AND
LIGHT-BUT-STEADY BREEZES AM GOING TO HOLD OFF ON A FORMAL FOG
MENTION FOR NOW AND MONITOR TRENDS TO MAKE SURE AUTOMATED SITES DO
NOT START DROPPING BELOW 1 MILE...WHICH WOULD CERTAINLY JUSTIFY A
LAST-MINUTE FOG INCLUSION SHOULD THIS START OCCURRING.
TODAY (7AM-7PM): BY THE TIME 12Z/7AM ROLLS AROUND IN A FEW
HOURS...ANY LINGERING AREAS OF LIGHT MEASURABLE RAIN SHOULD
LARGELY BE CONFINED TO THE EASTERN HALF OF THE CWA...BUT EVEN THIS
SHOULD BE STEADILY PUSHING OUT WITH TIME...LEAVING ONLY A FEW
HOURS OF LIGHT DRIZZLE POTENTIAL IN ITS WAKE. WILL OBVIOUSLY
UPDATE AGAIN BEFORE SUNRISE BASED ON RADAR TRENDS...BUT FOR NOW WILL
CARRY ONLY A FEW HOURS OF LIKELY POPS IN EASTERN ZONES BEFORE
DROPPING DOWN TO ONLY SLIGHT 20 POPS IN EXTREME EASTERN COUNTIES
ALONG HWY 81 BY LATE MORNING (AGAIN THOUGH...SPOTTY DRIZZLE COULD
EXTEND BACK TO THE TRI-CITIES AREA WELL-PAST SUNRISE). ONCE
RAIN/DRIZZLE FINALLY ENDS...THE BIG QUESTION IS HOW QUICKLY/SLOWLY
DO CLOUDS VACATE FROM WEST-TO-EAST...AS THE MID LEVEL SHORTWAVE
TROUGH LIFTS AWAY FROM THE AREA INTO IA/MN...PROVIDING A BRIEF
PERIOD OF SHORTWAVE RIDGING FOR THIS AFTERNOON/EVENING. IF
ANYTHING...HAVE SLIGHTLY SLOWED DOWN THE CLEARING TREND FROM
PREVIOUS FORECAST...BUT AM COUNTING ON LIGHT WESTERLY LOW-LEVEL
FLOW TO GRADUALLY SCOUR OUT LOW STRATUS (OR AT LEAST TURN IT INTO
A SCATTERED COVERAGE) AS THE DAY WEARS ON. THAT BEING SAID...SOME
OF THE LATEST TRENDS IN 900-850MB RELATIVE HUMIDITY ALONG WITH SKY
COVER PROGS FROM THE LATEST HRRR SUGGEST THAT COUNTIES EAST OF
HIGHWAY 281 COULD HANG ONTO CONSIDERABLE CLOUD COVER WELL INTO THE
AFTERNOON WITH ANY APPRECIABLE CLEARING COMING LATE IN THE DAY.
THE BOTTOM LINE IS THAT ALTHOUGH CONFIDENCE IS NOT
OVERLY-HIGH...EXPECT SKY COVER TODAY IN THE WESTERN 1/2 OF THE
CWA TO IMPROVE FROM CLOUDY TO PARTLY CLOUDY/MOSTLY SUNNY...WHILE
THE EASTERN HALF ONLY IMPROVES FROM CLOUDY TO MOSTLY CLOUDY/PARTLY
CLOUDY. OBVIOUSLY THE CLOUD TRENDS WILL HAVE A DECENT IMPLICATION
ON HIGH TEMPERATURES THIS AFTERNOON. ALTHOUGH DID NOT FOLLOW
IT OUTRIGHT...DID TREND HIGHS TOWARD THE LATEST RAP13
NUMBERS...WHICH LOWERED VALUES GENERALLY 3-4 DEGREES IN MOST
CENTRAL/EASTERN COUNTIES...WHILE LEAVING WESTERN ZONES FAIRLY
SIMILAR TO PREVIOUS FORECAST. THE NET RESULT AIMS FROM NEAR-70 FAR
EAST...LOW-MID 70S TRI-CITIES AREA...AND UPPER 70S/LOW 80S FAR
WEST/SOUTHWEST. AS FOR WINDS TODAY...INITIALLY SOUTH/SOUTHEAST
BREEZES THIS MORNING WILL STEADILY MORE SOUTHWESTERLY IF NOT
WESTERLY AS THE DAY WEARS ON...BUT WITH SUSTAINED SPEEDS NOT
EXPECTED TO AVERAGE MORE THAN 10-15 MPH.
THIS EVENING/TONIGHT (7PM-7AM): IN SHORT...EXPECT A FAIRLY
TRANQUIL EVENING FOLLOWED BY A SOMEWHAT MORE ACTIVE LATE NIGHT
PERIOD WITH POTENTIALLY A FEW STRONG STORMS...ALTHOUGH CONFIDENCE
IS STILL A BIT LOW ON WHETHER THUNDERSTORM DEVELOPMENT WILL BE
MORE ISOLATED OR MORE WIDESPREAD. AS A RESULT...HAVE KEPT ALL
POST-MIDNIGHT POPS CAPPED AT NO HIGHER THAN 30-50 PERCENT FOR
NOW...AND WITH THE HIGHEST VALUES LARGELY FOCUSED OVER THE WESTERN
1/2 OF THE CWA. LOOKING ALOFT TO THE MID-UPPER LEVELS...A BRIEF
PERIOD OF SHORTWAVE RIDGING THIS EVENING WILL QUICKLY GIVE WAY TO
A LOW AMPLITUDE DISTURBANCE MOVING INTO THE CENTRAL PLAINS IN
SOUTHWEST FLOW ALOFT...ALONG THE VERY LEADING EASTERN EDGE OF THE
MAIN WESTERN CONUS TROUGH. ALTHOUGH THERE ARE THE TYPICAL VARIOUS
DEPICTIONS OF HOW CONVECTION WILL PLAY OUT TONIGHT AMONGST THE
VARIOUS DETERMINISTIC AND HIGHER-RES MODELS...GENERALLY TEND TO
PREFER THE DEPICTION OF THE 00Z NSSL 4KM-WRF AT THIS TIME. THIS
MEANS REASONABLY HIGH CONFIDENCE IN A DRY EVENING (PRE-
MIDNIGHT)...ALTHOUGH CONVECTION COULD ALREADY BE APPROACHING THE
CWA FROM SOUTHWEST NEB/SOUTHWEST KS AS IT FIRES UP ALONG THE NOSE
OF AN INCREASING 30-40KT LOW LEVEL JET EVIDENT AT 850MB. THEN
POST-MIDNIGHT...EXPECT ISOLATED TO SCATTERED SHOWERS/STORMS TO
MOVE INTO AND/OR DEVELOP DIRECTLY OVER THE CWA AS THE MID LEVEL
WAVE AND ASSOCIATED LOW LEVEL JET FORCING SPREADS FARTHER EAST.
COULD SEE A MORE CONCENTRATED ZONE OF CONVECTION THAT COULD
EVENTUALLY NECESSITATE LIKELY POPS...BUT JUST TOO TOUGH TO TELL
WHERE EXACTLY THIS WOULD BE YET. THAT BEING SAID...ALTHOUGH STORMS
WILL BE POSSIBLE ALMOST ANYWHERE BETWEEN MIDNIGHT-SUNRISE...THE
WESTERN HALF OF THE CWA SHOULD BE MOST FAVORED. AS FOR STORM
INTENSITY...THAT WILL OBVIOUSLY DEPEND HEAVILY ON THE DEGREE OF
ELEVATED INSTABILITY. AS IS COMMON...THE LATEST 06Z NAM SEEMS A
BIT HIGH WITH 850-700MB LAYER CAPE POTENTIALLY EXCEEDING 2500
J/KG...WHILE THE GFS LOOKS A BIT MORE REALISTIC BUT STILL HAS
ELEVATED CAPE INCREASING TO AROUND 1000 J/KG. ALTHOUGH DEEP LAYER
SHEAR IS PROGGED TO REMAIN FAIRLY WEAK AT ONLY AROUND 20-25KT AT
MOST...THIS INSTABILITY (ESPECIALLY IF THE NAM IS REMOTELY
CORRECT) COULD EASILY SUPPORT A FEW STRONG TO MARGINALLY SEVERE
HAIL CORES AT LEAST IN THE NICKEL-QUARTER RANGE. IN ORDER TO
REMAIN REASONABLY CONSISTENT WITH THE LACK OF AN OFFICIAL MARGINAL
RISK AREA ON THE INITIAL SPC DAY 1 OUTLOOK...WILL KEEP A FORMAL
SEVERE STORM MENTION OUT OF THE HAZARDOUS WEATHER OUTLOOK FOR
NOW...BUT WILL INTRODUCE A MENTION OF LATE-NIGHT STRONG STORM
POTENTIAL TO GET THE BALL TRENDING THAT DIRECTION. TURNING TO
OTHER ELEMENTS...BREEZES TONIGHT SHOULD GENERALLY AVERAGE 5-10 MPH
FROM THE SOUTHEAST AS A WEAK COLD FRONT STALLS OUT JUST NORTH OF
THE CWA THIS EVENING AND LOW PRESSURE DEVELOPS WEST. MADE VERY
LITTLE CHANGE TO LOW TEMPS...AIMING MOST OF THE CWA BETWEEN 57-61
DEGREES. ON ONE LAST NOTE...THE PRESENCE OF FAIRLY LIGHT SOUTHEAST
BREEZES LATE TONIGHT...AND FAIRLY CLOSE SURFACE TEMP/DEWPOINT
DEPRESSIONS ARGUE THAT FOG COULD POSSIBLY BECOME AN ISSUE IN SOME
AREAS...AND THIS HAS MODEST SUPPORT IN THE LATEST SREF VISIBILITY
PROGS. HOWEVER...GIVEN THAT CONFIDENCE IN IMPACTFUL FOG (GENERALLY
1 MILE VISIBILITY OR LESS) ISN/T EVEN THAT HIGH FOR THIS
MORNING...IT/S HARD TO PUT MUCH FAITH IN TRENDS FOR 24 HOURS FROM
NOW...SO WILL KEEP IT OUT OF THE FORECAST FOR NOW AND LET THE
FOCUS REMAIN ON THE THUNDERSTORM CHANCES.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 400 AM CDT THU MAY 14 2015
THIS SECTION WILL BE ADDED WITHIN THE NEXT HOUR...STAY TUNED.
&&
.AVIATION...(FOR THE 06Z KGRI/KEAR TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 100 AM CDT THU MAY 14 2015
OVERALL NO MAJOR CHANGES FROM PREVIOUS 00Z PACKAGE...AS A
COMBINATION OF MVFR/IFR CONDITIONS ARE EXPECTED TO DOMINATE AT
LEAST THE FIRST HALF OF THE PERIOD...AND POSSIBLY A FEW HOURS
BEYOND...WITH VFR CEILING/VISIBILITY THEN RETURNING FROM ROUGHLY
MID-AFTERNOON ONWARD. WHILE THIS GENERAL TREND CARRIES FAIRLY HIGH
CONFIDENCE...THERE ARE PLENTY OF QUESTION MARKS ESPECIALLY WITH
REGARD TO VISIBILITY...AND WHETHER OR NOT AT LEAST A BRIEF PERIOD
OF MORE SUBSTANTIAL FOG COULD SET IN BEHIND THE RAIN SHIELD THIS
MORNING...BUT FOR NOW HAVE NOT GONE TOO PESSIMISTIC DOWN THIS
ROAD. SPEAKING OF RAIN...AT LEAST THROUGH THESE FIRST 5-6 HOURS
OR SO...A FAIRLY STEADY LIGHT RAIN WILL PERSIST AT BOTH TERMINALS
BEFORE POSSIBLY TRANSITIONING TO A FEW HOURS OF LIGHT DRIZZLE
BEFORE PRECIP ENDS COMPLETELY. WILL AIM FOR A RETURN TO PREVAILING
VFR VISIBILITY BY MID-LATE MORNING...BUT WILL HOLD ONTO AN MVFR
CEILING INTO MID-AFTERNOON BEFORE SCATTERING OUT/LIFTING TO VFR
LEVELS. CONFIDENCE IS FAIRLY HIGH IN VFR CONDITIONS FOR THE LATTER
SEVERAL HOURS OF THE PERIOD THURSDAY EVENING. THERE IS AN OUTSIDE
CHANCE THAT ISOLATED SHOWERS/THUNDERSTORMS COULD BE STARTING TO
DEVELOP IN THE GENERAL AREA TOWARD THE VERY END OF THE
PERIOD...BUT THIS SEEMS MORE LIKELY DURING THE FOLLOWING 6 HOURS
SO WILL HOLD OFF ON ANY MENTION FOR NOW.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...ROSSI
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
328 AM CDT THU MAY 14 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CDT THU MAY 14 2015
TODAY AND TONIGHT...TIMING TOOLS AND THE HRRR MODEL SHOW THE RAIN
SHIELD ROTATING NORTHEAST AT 15 MPH THIS MORNING SUGGESTING AN EXIT
TIME AROUND 15Z. SATELLITE SHOWS TRAPPED BOUNDARY LAYER MOISTURE
PRODUCING LOW STRATUS WHICH WILL SLOWLY ERODE THIS MORNING AS WEST
AND NORTHWEST WINDS INCREASE TO 10 MPH AFTER SUNRISE. THE
TEMPERATURE FORECAST FOLLOWS THE UPPER EDGE OF THE MODEL ENVELOP FOR
HIGHS IN THE 70S TO 80 SOUTH.
WEAK HIGH PRESSURE WILL BUILD INTO THE FCST AREA THIS AFTERNOON WITH
A FRONT SETTING UP ACROSS SRN NEB BY LATE THIS AFTN. THE NAM
SUGGESTS A LEAD DISTURBANCE OVER AZ THIS MORNING WILL MOVE THROUGH
THE ROCKIES TODAY AND LIFT THE FRONT NORTH TO NEAR THE NORTH PLATTE
VALLEY TONIGHT. MODEST WARM AIR ADVECTION FROM 850MB ON UP HELPS TO
LIFT THE FRONT NORTH BUT ALSO DESTABILIZES THE ATMOSPHERE PRODUCING
SCATTERED TSTMS FROM 06Z ONWARD.
INSTABILITY PROFILES IN THE NAM INDICATE AROUND 1500 J/KG OF CAPE
COMPUTED AT 800 MB AND 3000 J/KG AT 850 MB. THE DRIER GFS SHOWS VERY
LITTLE INSTABILITY AT THESE LEVELS. THE SREF SUPPORTS THE NAM SOLN
DRIVING PWAT TO AN INCH OVERNIGHT. LAPSE RATES ARE STEEP IN BOTH THE
GFS AND NAM BUT THE BULK SHEAR IS WEAK WITH LINEAR WIND FIELDS. THIS
WOULD SUGGEST THE POTENTIAL FOR PULSE TSTM BEHAVIOR WITH
HAIL...POSSIBLY BRIEFLY LARGE. POPS ARE SET AT 40 PERCENT TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 326 AM CDT THU MAY 14 2015
LITTLE HAS CHANGED OVER THE LAST 24 HOURS IN THE LONG RANGE.
DETERMINISTIC MODELS AND ENSEMBLE MEANS REMAIN IN SOUND AGREEMENT
WITH THE EVOLUTION OF THE UPPER LEVEL SYNOPTIC PATTERN THROUGH THE
MIDDLE OF NEXT WEEK. FORECASTER CONFIDENCE IS HIGH FOR THE PROLONGED
CONTINUATION OF AN ACTIVE PATTERN OVER THE CENTRAL PLAINS WITH
PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS.
LEAD SHORTWAVE EJECTS NORTHEAST INTO THE CENTRAL PLAINS FRIDAY
SETTING THE STAGE FOR POTENTIAL SEVERE WEATHER IN THE SANDHILLS
REGION. A 60KT UPPER LEVEL JET NOSES INTO THE CWA AS A LEE SIDE AREA
OF LOW PRESSURE DEEPENS OVER NORTHEAST COLORADO...WITH A SHARPENING
DRYLINE FROM SW NEBRASKA INTO WESTERN KS. A POLEWARD ADVANCING WARM
FRONT WILL ALSO STRETCH EAST ACROSS THE CWA...HOWEVER THE EXACT
PLACEMENT STILL REMAINS IN QUESTION. THUNDERSTORM INITIATION IS
EXPECTED BY MID TO LATE AFTERNOON IN A ZONE OF POOLING RICH THETA-E
AIR AND INCREASING INSTABILITY BETWEEN THE NORTHEAST SURGING DRYLINE
AND THE WARM FRONT. STRONG DEEP LAYER SHEAR IN EXCESS OF 40 KTS AND
STEEPENING MID-LEVEL LAPSE RATES WILL FOSTER AN ENVIRONMENT
FAVORABLE FOR THE DEVELOPMENT OF SUPERCELL THUNDERSTORMS CAPABLE OF
PRODUCING LARGE HAIL AND DAMAGING WINDS. TORNADO THREAT INCREASES
LATE IN THE DAY IN CONCERT WITH A STRENGTHENING LOW LEVEL
JET...WHICH WILL CREATE MORE FAVORABLE LOW LEVEL SHEAR PROFILES AND
ELONGATED HODOGRAPHS IN THE VICINITY OF THE WARM FRONT AND WESTWARD
TOWARD THE TRIPLE POINT IN THE EASTERN NEBRASKA PANHANDLE. SEVERAL
UNCERTAINTIES STILL REMAIN WITH THE SEVERE WEATHER SETUP FOR
FRIDAY...PRIMARILY DUE TO MODEL DIFFERENCES WITH THE POSITION OF THE
AFOREMENTIONED WARM FRONT. SCATTERED CONVECTION WILL BE ONGOING
FRIDAY MORNING IN A ZONE ISENTROPIC ASCENT ALONG AND NORTH OF THE
WARM FRONT AS IT MOVES NORTHWARD OUT OF KANSAS. MODELS ARE
STRUGGLING WITH THEIR PROGRESSION OF THE FRONT DUE TO DIFFERENCES IN
THEIR CONVECTIVE OUTPUT. ALSO OF CONCERN IS THE LACK OF CONVECTIVE
INHIBITION INDICATED IN MODEL FORECAST SOUNDINGS. A WEAK CAP FAVORS
AN EARLIER ONSET TO CONVECTION AND LIMITS THE DEGREE OF
DESTABILIZATION IN THE WARM SECTOR PRIOR TO STORM INITIATION.
THUNDERSTORM ACTIVITY PUSHES NORTHEAST ALONG THE NOSE OF A VEERING
LLJ FRIDAY NIGHT. A LARGE UPPER LEVEL LOW OVER THE DESERT SOUTHWEST
KICKS NORTHEAST INTO THE CENTRAL PLAINS SATURDAY AND THE ATMOSPHERE
OVER THE CWA RELOADS WITH ANOTHER ROUND OF SEVERE WEATHER POSSIBLE.
MODEL CONSENSUS HAS TRENDED A BIT FURTHER WEST WITH THE WEDNESDAY
EVENING RUNS. THE LEE SIDE AREA OF LOW PRESSURE FROM FRIDAY
RETROGRADES BACK WESTWARD...WITH A SFC TROUGH AXIS STRETCHING FROM
THE KS/CO BORDER NORTHWARD INTO WESTERN NEBRASKA. THUNDERSTORM
INITIATION IS LIKELY ONCE AGAIN DURING THE AFTERNOON HOURS ALONG AND
AHEAD OF THE SFC TROUGH AS STRONG UPPER LEVEL LIFT OVERSPREADS THE
INCREASINGLY UNSTABLE WARM SECTOR. WIND PROFILES LOOK FAIRLY
UNIDIRECTIONAL THROUGH A DEEP LAYER SATURDAY...SO THUNDERSTORMS WILL
LIKELY EXPERIENCE UPSCALE GROWTH WITH LARGE HAIL...DAMAGING
WINDS...AND LOCALLY HEAVY RAINFALL THE PRIMARY THREATS AS THEY TRACK
NORTH AND EAST THROUGH THE EVENING.
A TRANSITORY RIDGE MOVES OVER THE CENTRAL PLAINS EARLY IN THE WEEK
BRINGING A TEMPORARY PERIOD OF DRIER CONDITIONS. PRECIPITATION
CHANCES RAMP UP AGAIN BY TUESDAY AS ANOTHER UPPER LEVEL LOW MOVES
ONSHORE FROM THE PACIFIC AND INTO THE WESTERN CONUS. RAINFALL
CHANCES INCREASE AS A PLUME OF SUBTROPICAL MOISTURE ALOFT SURGES
NORTHEAST OUT OF THE BAJA REGION...WHILE NORTHWARD MOISTURE
TRANSPORT IN THE LOWER LEVELS LIFTS UP AND OVER THE WARM FRONT
SITUATED JUST SOUTH OF THE CWA. CROSS SECTION ANALYSIS OF THE GFS
AND EC SHOW STRONG AND PERSISTENT ISENTROPIC LIFT A OVER THE
CWA...ESPECIALLY TUESDAY NIGHT. EVEN THOUGH IT IS IN THE DAY 6-7
RANGE...STUCK WITH LIKELY POPS GIVEN THE HIGHLY FAVORABLE SETUP FOR
WIDESPREAD QPF AND STRONG MODEL CONSENSUS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1125 PM CDT WED MAY 13 2015
FOR THE KLBF TERMINAL...LOOK FOR RAIN SHOWERS TO COME TO AN END BY
07Z THURSDAY. PATCHY FOG WILL FOLLOW THE RAIN SHOWERS WITH CIGS
FALLING AS LOW AS 400 FT AGL WITH VISBYS DOWN TO 2SM. CIGS WILL
IMPROVE BY MID MORNING THURSDAY WITH MVFR CIGS OF 1500 FT AGL.
SKIES WILL CLEAR THURSDAY AFTERNOON AND REMAIN CLEAR THROUGH 06Z
FRIDAY. FOR THE KVTN TERMINAL...EXPECT LIGHT RAIN SHOWERS TO
CONTINUE THROUGH 10Z THURSDAY WITH PATCHY FOG POSSIBLE THEREAFTER
THROUGH MID MORNING THURSDAY. CIGS MAY FALL AS LOW AS 700 FT
OVERNIGHT WITH VISBYS DOWN TO 4SM. MVFR CIGS AROUND 1500 FT AGL
WILL DEVELOP AFTER MID MORNING...WITH VFR CIGS OF 5000 FT AGL
EXPECTED THURSDAY AFTERNOON. SKIES WILL CLEAR THURSDAY EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MARTIN
AVIATION...CLB
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1149 PM CDT WED MAY 13 2015
.SHORT TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 305 PM CDT WED MAY 13 2015
TONIGHT
LATEST SHORT TERM PROGS IN AGREEMENT SHOWING THAT GOING RAINFALL
FCST FOR TONIGHT IS ON TRACK WITH PCPN ACTIVITY DEVELOPING OVER KS
THEN EXPANDING NWD INTO THE CWA EARLY THIS EVENING. GIVEN
COMBINATION OF UPPER SUPPORT VIA POTENT VORT MAX/STRONG DIVG
WORKING IN TANDEM WITH RATHER MOIST 305K UPGLIDE...SEEMS
REASONABLE TO ASSUME THAT SEVERAL LOCATIONS SHOULD SEE RAINFALL
TOTALS OF AT LEAST HALF AN INCH MAINLY OVER THE SRN CWA WHERE
LIFT/MOISTURE WILL BE MORE PREVALENT. IN ADDITION...MODELS ARE
SHOWING INSTABILITY PARAMETERS WILL BE WEAK AT BEST SO ANY TSTM
DEVELOPMENT SHOULD BE ISOLATED.
DEE
THURSDAY THROUGH SATURDAY
TIMING AND POTENTIAL FOR SEVERE STORMS BOTH FRIDAY AND SATURDAY
WILL BE THE MAIN FORECAST CONCERNS.
OUR AREA WILL GENERALLY BE IN SOUTH OR SOUTHWEST MID TROPOSPHERIC
FLOW THE NEXT FEW DAYS. WATER VAPOR IMAGERY EARLY THIS WEDNESDAY
AFTERNOON...IN COMBINATION WITH EARLY AFTERNOON RAP MODEL
INTITIALIZATIONS...SHOWED FAIRLY IMPRESSIVE SHORTWAVE TROUGH FROM
COLORADO DOWN INTO WEST TEXAS. THIS WILL LIFT NORTHEAST ACROSS THE
AREA TONIGHT AND THURSDAY. BRIEF SHORTWAVE RIDGING BUILDS IN FOR
LATE THURSDAY/EARLY THURSDAY NIGHT...WHILE A STRONG CLOSED LOW
DIGS DOWN INTO NEVADA AND CALIFORNIA. GENERAL MODEL CONSENSUS
SHOWS THE CENTER OF THAT 500 MB LOW SHOULD LIFT OUT INTO NORTHEAST
WYOMING OR SOUTHEAST MONTANA BY SATURDAY EVENING.
THURSDAY...SHOWERS WILL LINGER AT LEAST IN THE MORNING...WITH
ISOLATED THUNDER POSSIBLE. CHANCES DECREASE THROUGH THE AFTERNOON.
EXPECT AT LEAST THE SOUTHWEST HALF OF OUR FORECAST AREA TO SEE
SOME AFTERNOON SUNSHINE AND THAT SHOULD HELP PUSH HIGHS INTO THE
70S THERE. AREAS FROM AROUND YANKTON DOWN TO ONAWA...HARLAN AND
RED OAK MAY ONLY TOP OUT FROM 65 TO 70. PCPN AMOUNTS THURSDAY ARE
EXPECTED TO BE MOSTLY UNDER 0.25 INCHES.
A WEAK COLD FRONT WILL SETTLE DOWN INTO THE FORECAST AREA THURSDAY
NIGHT AND THEN STALL. SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG
AND NORTH OF THE BOUNDARY THURSDAY NIGHT AS THE LOW LEVEL JET
INCREASES AND CAUSES ISENTROPIC LIFT. BEST FOCUS SEEMS TO BE OVER
SOUTHEAST NEBRASKA.
FRIDAY AND FRIDAY NIGHT WILL BE INTERESTING. SOUTHERLY LOW LEVEL
FLOW INCREASES AS LOW PRESSURE INITIALLY OVER NORTHEAST COLORADO AT
12Z FRIDAY LIFTS NORTH TO WEST/NORTHWEST OF VALENTINE BY 06Z
SATURDAY. HIGHS FRIDAY SHOULD REACH 75 TO 80...PUSHING BOUNDARY
LAYER CAPE VALUES INTO THE 1500 TO 3000 J/KG RANGE. 0-6 KM AGL BULK
SHEAR VALUES SHOULD BE MOSTLY 25-40 KNOTS. STORMS MAY INITIALLY BE
MOSTLY NORTH OF THE FRONT...BUT THEN COULD ALSO DEVELOP IN THE WARM
SECTOR OR FARTHER BACK TO THE WEST IN CENTRAL NEBRASKA LATER IN THE
DAY. DETAILS SHOULD BECOME MORE CLEAR WITH THURSDAY MODEL RUNS ON
THE LOCATION OF FRONTAL BOUNDARIES WHICH WILL HELP FOCUS THE
ACTIVITY IN THE AFTERNOON AND EVENING. STORM COVERAGE MAY DROP OFF
DRASTICALLY AFTER MIDNIGHT.
SATURDAY...OVERALL PARAMETERS ARE EXPECTED TO BE IN PLACE FOR
ANOTHER POSSIBLE SEVERE EVENT...BUT NOT COMPLETELY SOLD ON THAT
SINCE IT WILL AT LEAST SOMEWHAT DEPEND ON WHAT HAPPENS FRIDAY. MID
LEVEL WINDS SHOULD INCREASE AND THEREFORE BULK SHEAR VALUES MAY
END UP HIGHER THAN THOSE FRIDAY. TIMING OF CONVECTION WILL BE THE
KEY.
MILLER
.LONG TERM...(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 305 PM CDT WED MAY 13 2015
STORMS SHOULD LINGER INTO SATURDAY NIGHT...WITH SHOWERS/A FEW
EMBEDDED STORMS POSSIBLE SUNDAY MORNING. THE 12Z GFS WAS MOSTLY
DRY IN OUR AREA SUNDAY...BUT THE 12Z ECMWF WAS ABOUT 6 HOURS
SLOWER LIFTING PCPN OUT OF THE AREA. SO...FOR NOW WE HAVE KEPT
SOME LOW POPS SUNDAY IN OUR NORTHERN ZONES SUNDAY.
SUNDAY NIGHT THROUGH TUESDAY SHOULD BE LESS ACTIVE AS HIGH PRESSURE
BUILDS INTO THE REGION WITH COOL TEMPERATURES. SOME LOWS COULD DROP
DOWN TO NEAR 40. IT APPEARS THAT CHANCES FOR SHOWERS/STORMS WILL
INCREASE AGAIN BY TUESDAY NIGHT AND WEDNESDAY AS SHORTWAVE ENERGY
MOVES IN FROM THE WEST/SOUTHWEST.
MILLER
&&
.AVIATION...(06Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1140 PM CDT WED MAY 13 2015
VSBYS/CIGS HAVE DROPPED TO MVFR WITH THE BAND OF RAIN THAT MOVED
ACROSS THE FORECAST AREAS THIS EVENING. THESE CONDITIONS WILL
CONTINUE THROUGH THURSDAY MORNING...HOWEVER...OBS/RAP13 SHOW THERE
IS AN AREA OF DRIER AIR THAT WILL AFFECT THE KOMA/KLNK WITH MORE
VARIABLE CONDITIONS...WHERE VFR CONDITIONS WILL BE POSSIBLE BEFORE
DROPPING BACK TO MVFR/IFR THROUGH 18-00Z. LOOK FOR IMPROVING
CONDITIONS WITH DECREASING CLOUDS FROM WEST TO EAST THURSDAY
AFTERNON.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DEE/MILLER
LONG TERM...MILLER
AVIATION...ZAPOTOCNY
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
256 AM PDT THU MAY 14 2015
.SYNOPSIS...UNSEASONABLY COOL AND UNSETTLED WEATHER IS EXPECTED
THROUGH SATURDAY AS A PACIFIC STORM SYSTEM IMPACTS THE REGION. RAIN
AND MOUNTAIN SNOW CAN BE EXPECTED AREA WIDE WITH NORTHERN AREAS
FAVORED ON THURSDAY AND SOUTHERN AREAS FAVORED ON FRIDAY. SOME
SCATTERED SHOWERS MAY LINGER ON SATURDAY BEFORE BRIEF IMPROVEMENT
ARRIVES SUNDAY. ANOTHER STORM SYSTEM WILL IMPACT THE REGION EARLY
NEXT WEEK WITH MORE SHOWER AND THUNDERSTORM CHANCES.
&&
.SHORT TERM...THROUGH SATURDAY NIGHT.
THE CALENDAR MIGHT SAY MAY THE WEATHER PATTERN LOOKS MORE LIKE
FEBRUARY WITH AN ACTIVE PACIFIC JET STREAM BRINGING YET ANOTHER
STRONG TROUGH INTO THE SOUTHWEST. THIS STORM WILL IMPACT THE REGION
IN TWO DOSES WITH THE LEAD SHORTWAVE MOVING ONSHORE TODAY AS IT
ROTATES AROUND THE PARENT LOW...FOLLOWED BY THE PARENT LOW WHICH
MOVES ONSHORE IN SOUTHERN CALIFORNIA ON FRIDAY AND DRAGS EAST ACROSS
THE MOJAVE DESERT.
WIDESPREAD HIGH CLOUDS IN ADVANCE OF THIS LEAD SHORTWAVE HAVE
OVERSPREAD THE FORECAST AREA AND WILL CONTINUE TO ADVANCE INTO THE
REGION TODAY WITH CLOUD DECKS LOWERING THROUGH THE DAY. SHOWERS WILL
BREAK OUT FIRST ACROSS THE SIERRA WHERE SNOW LEVELS NEAR 6500 FEET
WILL LEAD TO THE LIKELIHOOD OF ACCUMULATING SNOW THURSDAY AFTERNOON.
WHILE ACCUMULATIONS BY SIERRA STANDARDS WONT BE TOO IMPRESSIVE...
BEING MID-MAY IT CERTAINLY MAY CATCH SOME OFF GUARD. ADDITIONAL
SHOWERS WILL BREAK OUT ACROSS NORTHERN MOHAVE COUNTY WHERE THE PAST
FEW RUNS OF THE HRRR HAVE BROKEN OUT SOME ISOLATED THUNDERSTORMS BY
EARLY AFTERNOON. BY LATER IN THE DAY THURSDAY ADDITIONAL SHOWERS
AND STORMS MAY FORM ACROSS PARTS OF THE MOJAVE DESERT AND EVEN MAY
CREEP INTO THE LAS VEGAS VALLEY. AMOUNTS IN THE DESERTS WILL
GENERALLY BE LIGHT...UNDER A TENTH OF AN INCH.
WINDS WILL AGAIN BE GUSTY TOMORROW AND I TOYED WITH THE IDEA OF A
WIND ADVISORY FOR THE WESTERN MOJAVE DESERT BUT WITH WIDESPREAD
OVERCAST...AND SOME SHOWER ACTIVITY...I DONT THINK MIXING WILL BE
OPTIMAL FOR AN ALREADY BORDERLINE WIND EVENT. SO I DECIDED AGAINST
ANY WIND HEADLINES.
BY FRIDAY...THE PRIMARY LOW MOVES ASHORE IN SOUTHERN CALIFORNIA. GFS
HAS BEEN FAIRLY CONSISTENT ON THE PAST SEVERAL RUNS NOW ON BRINGING
A HEALTHY STRIPE OF PRECIPITATION TO THE MOJAVE DESERT MAINLY SOUTH
OF INTERSTATE 40. QPF NUMBERS BY THE GFS ARE PRETTY SIGNIFICANT BY
MAY STANDARDS WITH 0.25 TO 0.50 INCH AMOUNTS ADVERTISED (KEEP IN
MIND MONTHLY AVERAGE RAINFALL THE ENTIRE MONTH OF MAY IN THIS PART
OF THE DESERT IS CLOSER TO A TENTH OF AN INCH). NAM IS MUCH DRIER
AND ECMWF KEEPS THE BRUNT OF THE MOISTURE FURTHER SOUTH....BUT I DO
LIKE THE GFS CONSISTENCY AND THE SOLUTION MAKES SOME METEOROLOGICAL
SENSE BUT THE NUMBERS ARE EXCESSIVE. I OPTED FOR A MIDDLE GROUND AND
RAISED POPS AND QPF ACCORDINGLY ACROSS THE MOJAVE DESERT ESPECIALLY
SOUTH OF I-40 BUT KEPT RAINFALL TOTALS UNDER A QUARTER OF AN INCH.
FURTHER NORTH PLACES LIKE LAS VEGAS WILL LIKELY SEE A COOL CLOUDY
DAY MUCH LIKE LAST FRIDAY WITH SOME LIGHT SHOWERS AROUND BUT AMOUNTS
AT THIS TIME AGAIN LOOK LIGHT. BE PREPARED FOR DRAMATICALLY COOLER
TEMPERATURES...LIKELY BEING 20 TO 30 DEGREES BELOW SEASONAL
AVERAGES.
ON SATURDAY THE TROUGH WILL DEPART TO THE EAST BUT SOME WRAP AROUND
MOISTURE AND INSTABILITY MAY STILL SPARK SOME CLOUDS AND SHOWERS
ESPECIALLY ACROSS THE SOUTHERN GREAT BASIN AND MOHAVE COUNTY IN
ARIZONA. OTHERWISE TEMPERATURES WILL CREEP UPWARD SLIGHTLY SATURDAY
BUT STILL BE AROUND 15 DEGREES BELOW NORMAL.
.LONG TERM...SUNDAY THROUGH THURSDAY.
SUNDAY...ATTENTION WILL TURN TO THE NEXT DEVELOPING CLOSED LOW OFF
THE CALIFORNIA COAST. SOUTH TO SOUTHWEST FLOW WILL STRENGTHEN AHEAD
OF IT LEADING TO SOUTHERLY SURFACE WINDS GENERALLY GUSTING 20-30 MPH
ACROSS THE FORECAST AREA SUNDAY AFTERNOON. BROAD UPWARD FORCING
AHEAD OF THE LOW WILL COMBINE WITH SOME LINGERING MOISTURE AND
INSTABILITY OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN ZONES
TO PRODUCE SOME AFTERNOON THUNDERSTORMS. THE UPPER LOW IS FORECAST
TO SWING INLAND MONDAY WITH SOME ADDITIONAL MOISTURE MOVING INTO
SOUTHERN NEVADA AND NORTHWEST ARIZONA. DIFFLUENT FLOW AND COOLING
ALOFT WILL HELP DESTABILIZE THE ATMOSPHERE AND LEAD TO MORE
EXTENSIVE COVERAGE AND MORE ORGANIZED BANDS OF CONVECTION EXTENDING
DOWN INTO CLARK AND MOHAVE COUNTIES MONDAY AFTERNOON.
THE UPPER LOW IS FORECAST TO LIFT UP ACROSS THE ROCKIES BY TUESDAY
LEAVING A WEAK BROAD TROUGH OVER THE WESTERN STATES THROUGH
THURSDAY. THE MEDIUM RANGE MODELS ARE ALL IN FAIRLY GOOD AGREEMENT
THAT THIS WILL PROVIDE A PATH FOR YET ANOTHER PACIFIC LOW PRESSURE
SYSTEM TO DROP INTO SOUTHERN NEVADA GOING INTO THE MEMORIAL DAY
WEEKEND. THIS PATTERN WILL KEEP TEMPERATURES SLIGHTLY BELOW NORMAL
THROUGH THE PERIOD WITH A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS
OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN. THEN...IT IS
LOOKING LIKE THERE WILL BE THE POTENTIAL FOR COOLER AND MORE
UNSETTLED WEATHER HEADING INTO THE MEMORIAL DAY WEEKEND.
&&
.AVIATION... FOR MCCARRAN...INCREASING CLOUDS AND LOWERING CEILINGS
EXPECTED TODAY AS A PACIFIC STORM IMPACTS THE REGION. SOUTH WINDS OF
15-25KT EXPECTED WITH GUSTS TO 30KTS BUT SOME VARIABILITY POSSIBLE
WHILE SHOWERS MOVE THROUGH THE VALLEY IN THE LATE AFTERNOON. CIGS
FALLING IN THE 8-10K FT RANGE THIS AFTERNOON AND EVENING. ADDITIONAL
RAIN AND REDUCED CIGS POSSIBLE FRIDAY.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...WIDESPREAD BKN-OVC CONDITIONS EXPECTED TODAY WITH CLOUD
DECKS LOWERING THROUGH THE DAY. SCT SHOWERS AND THUNDERSTORMS LIKELY
IN NORTHWEST ARIZONA AS WELL AS INYO COUNTY THROUGH MIDDAY...BEFORE
SPREADING INTO THE MOJAVE DESERT THURSDAY AFTERNOON. BEST CHANCES
FOR SHOWERS AND STORMS WILL BE NORTH OF INTERSTATE 40. ADDITIONAL
RAIN EXPECTED FRIDAY ESPECIALLY SOUTH OF A KDAG-KLAS-KSGU LINE.
BREEZY SOUTH WINDS OF 15-20KTS AND GUSTS TO 30KTS EXPECTED.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...OUTLER
LONG TERM...ADAIR
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
330 AM MDT THU MAY 14 2015
.SYNOPSIS...
ACTIVE WEATHER PATTERN WILL CONTINUE FOR THE FORESEEABLE FUTURE.
SHOWERS AND THUNDERSTORMS WILL BE MOST NUMEROUS OVER THE NORTH AND
WEST TODAY THROUGH SATURDAY...AND A FEW STORMS NEAR THE TEXAS
BORDER MAY BE STRONG TO SEVERE THIS AFTERNOON AND EVENING AND FRIDAY
AFTERNOON AND EVENING. GUSTY SOUTHWEST WINDS WILL AFFECT NORTHEAST
NEW MEXICO FRIDAY AFTERNOON. SOME DRYING SATURDAY NIGHT INTO SUNDAY
THEN A WETTER PERIOD TO FOLLOW MONDAY NIGHT AND TUESDAY.
&&
.DISCUSSION...
WIDESPREAD HIGH CLOUDS ASSOCIATED WITH THE NEXT DISTURBANCE TO
AFFECT NEW MEXICO WILL PERSIST TODAY. PATCHY FOG AT KCAO KEEPS
VARYING AT WINDS FLOP AROUND...WITH MORE WIDESPREAD FOG TO THE NORTH
AND EAST. NOT EXPECTING THAT WILL HANG AROUND FOR VERY LONG THIS
MORNING. RUC SHOWING SOME LIGHT PRECIPITATION DEVELOPING THIS
MORNING OVER THE SRN HIGH TERRAIN SO MADE SOME ADJUSTMENTS FOR THAT.
SPC OUTLOOK BRINGS A MARGINAL AREA INTO THE FAR EAST CENTRAL/SE FOR
TODAY AND GENERALLY A SIMILAR AREA DRAWN FOR FRIDAY AS THE LEAD
DISTURBANCE EXITS. WINDS COULD BE GUSTY FRIDAY SOUTH AND EAST AS H7
WINDS INCREASE TO THE 30-40 KT RANGE. THE MAIN UPPER LOW/FRONT PASS
THROUGH FRIDAY NIGHT/SATURDAY. SOME BIG DISPARITIES POP GUIDANCE
WISE...TOOK A MIDDLE OF THE ROAD APPROACH...BUT IN GENERAL THEY ARE
HIGHER THAN WHAT WAS INHERITED. HIGHS FRIDAY THROUGH SUNDAY BELOW
AVERAGE OVER THE ENTIRE FORECAST AREA...ESPECIALLY SATURDAY...WITH
SOME WARMING SUNDAY. HIGHS STAY PRETTY MUCH NEAR TO BELOW AVERAGE
THROUGH THE MIDDLE OF NEXT WEEK AS YET ANOTHER UPPER LOW AND FRONT
BRING A WETTER PERIOD TO THE REGION MONDAY NIGHT AND TUESDAY.
&&
.FIRE WEATHER...
A FEW SHOWERS AND THUNDERSTORMS...NOT NEARLY AS HEAVY AS WHAT FELL
TUE AND EARLY WED...WILL DEVELOP ACROSS THE FAR NORTHERN PORTION OF
NM THIS AFTN...PRIMARILY ACROSS THE HIGHER TERRAIN. THE FAR WEST MAY
ALSO SEE ISOLATED AFTN AND EVE SHOWER OR STORM ACTIVITY...BUT
MEASURABLE RAINFALL IS UNLIKELY IN MOST CASES. FCST MODELS ARE STILL
PRETTY SUPPORTIVE OF ANOTHER ROUND OF WETTING MOISTURE FRIDAY INTO
SATURDAY AS ANOTHER VIGOROUS AND WET TROUGH ALOFT APPROACHES AND
MOVES ACROSS THE CENTRAL AND SOUTHERN ROCKIES. WETTING RAIN/HIGHER
ELEVATION SNOW WITH THIS SYSTEM IS EXPECTED TO FAVOR THE WESTERN
HALF OF NORTH AND CENTRAL NM...THOUGH THERE APPEARS TO BE SOME
INCREASE IN THE CHANCE FOR A FEW STRONG THUNDERSTORMS ACROSS THE
EAST HALF OF THE EASTERN PLAINS. CONFIDENCE REMAINS PRETTY HIGH AS
FCST MODELS HAVE BEEN GETTING MORE CONSISTENT ON THIS SCENARIO OVER
THE PAST SEVERAL MODEL RUNS. VENTILATION WILL BE EXCELLENT NEARLY
ALL AREAS THE NEXT 3 AFTNS DUE LARGELY TO THE STRONGER TRANSPORT
WINDS. MODEL DERIVED MIXING HEIGHTS STILL MAY BE A BIT TOO HIGH
GIVEN CLOUD COVER AND GENERALLY BELOW NORMAL TEMPS...SO THERE MAY
STILL BE A FEW MORE POCKETS OF VERY GOOD RATHER THAN EXCELLENT
VENTILATION THAN CURRENTLY INDICATED. RATES WILL DROP SHARPLY
SUN...BUT THEN PICK BACK UP SHARPLY AGAIN FOR EARLY TO MID WEEK NEXT
WEEK. SAT APPEARS TO BE THE COOLEST DAY WITH SNOW LEVELS AT THEIR
LOWEST... POSS GETTING AS LOW AS 8500 TO 9500 FEET ACROSS THE NORTH
AND WEST CENTRAL COUNTIES. FRI APPEARS TO BE THE WINDIEST DAY...
PARTICULARLY ACROSS THE NE THIRD OF THE FCST AREA.
STILL LOOKING AT A BREAK IN THE SHOWERY/COOLER WEATHER SUN INTO MUCH
OF MON WITH SOME SHORTWAVE RIDGING AHEAD OF ANOTHER PACIFIC TROUGH.
BACK DOOR COLD FRONT INTRUSION INTO AT LEAST THE EAST HALF OF THE
STATE SUNDAY NIGHT AND MON TO INCREASE MOISTURE SOME INITIALLY WITH
AN ADDED BOOST FROM GULF MOISTURE LATER MON INTO TUE SHOULD
ENCOURAGE DEVELOPMENT OF ANOTHER ROUND OF SHOWERS/THUNDERSTORMS...
MAINLY ALONG THE CENTRAL MOUNTAIN CHAIN ON EAST. BUT THERE IS ALSO
SOME POTENTIAL FOR SPOTTY ACTIVITY BETWEEN THE DIVIDE AND THE
CENTRAL MTN CHAIN AS MODELS MORE OFTEN THAN NOT KEEP THE MOISTURE
FARTHER EAST THAN WHAT IS OFTEN THE CASE. IN FACT SOME MODELS ARE
BEGINNING TO CREEP THE WETTING PRECIP FARTHER WEST ON MOST RECENT
COUPLE OF RUNS. THIS WESTWARD CREEP WILL CONTINUE TO BE MONITORED.
ANOTHER PACIFIC TROUGH SHOULD APPROACH THE AREA LATE NEXT WEEK. NOT
LOOKING AT ANY ORGANIZED CRITICAL FIRE WEATHER GROWING EVENTS NEXT
WEEK ALTHOUGH SUSPECT THERE WILL BE SOME AFTERNOON BREEZES. PRECIP
COVERAGE IS STILL UNCERTAIN...BUT AT THIS TIME LOOKS TO BE A LITTLE
FARTHER EAST THAN WHAT WAS THE CASE THIS PAST TUE/WED PERIOD.
43
&&
.AVIATION...
06Z TAF CYCLE
VFR CONDITIONS TO PERSIST AT AREA TERMINALS...EXCEPT AT KROW WHERE
IFR VSBYS IN FOG ARE POSSIBLE EARLY THURSDAY MORNING. SOME POTENTIAL
FOR FOG DEVELOPMENT AT KTCC AS WELL...BUT FORECASTER CONFIDENCE
TOO LOW TO INCLUDE IN TAF. OTHERWISE...LOOK FOR INCREASING
SOUTHWEST LOW LEVEL FLOW THURSDAY WITH WINDY CONDITIONS BY
AFTERNOON. HIGHEST GUSTS FORECAST AT KLVS THURSDAY AFTERNOON
AROUND 36-38KTS. HIGH-BASED SHOWERS LIKELY NORTH WITH GUSTY WINDS
MAY IMPACT KFMN AND KGUP LATE DAY. A FEW THUNDERSTORMS ARE
POSSIBLE LATE DAY AS WELL...MAINLY NEAR THE TEXAS BORDER AND ACROSS
THE NORTHEAST QUARTER...POSSIBLY IMPACTING KTCC.
11
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 74 44 61 41 / 20 30 30 50
DULCE........................... 69 40 57 35 / 30 30 40 70
CUBA............................ 70 43 59 35 / 20 10 40 60
GALLUP.......................... 71 38 59 35 / 10 10 30 50
EL MORRO........................ 66 36 56 35 / 5 10 30 60
GRANTS.......................... 71 38 61 33 / 5 10 30 40
QUEMADO......................... 68 37 60 38 / 5 10 20 50
GLENWOOD........................ 78 42 68 43 / 5 10 20 30
CHAMA........................... 64 33 53 31 / 30 30 40 70
LOS ALAMOS...................... 67 46 61 39 / 10 10 30 40
PECOS........................... 66 40 60 38 / 10 10 20 30
CERRO/QUESTA.................... 68 36 60 35 / 20 20 20 40
RED RIVER....................... 60 34 55 30 / 30 20 20 40
ANGEL FIRE...................... 61 35 56 30 / 20 20 20 40
TAOS............................ 68 38 61 35 / 20 10 20 40
MORA............................ 65 39 60 37 / 20 10 20 30
ESPANOLA........................ 73 40 65 43 / 10 10 20 30
SANTA FE........................ 70 39 62 40 / 10 10 20 40
SANTA FE AIRPORT................ 73 41 64 37 / 10 10 20 30
ALBUQUERQUE FOOTHILLS........... 74 44 64 46 / 10 10 20 30
ALBUQUERQUE HEIGHTS............. 77 49 67 44 / 5 5 20 20
ALBUQUERQUE VALLEY.............. 78 44 69 45 / 5 5 20 20
ALBUQUERQUE WEST MESA........... 77 45 69 44 / 10 5 20 20
LOS LUNAS....................... 77 47 71 42 / 5 5 20 20
RIO RANCHO...................... 77 48 68 44 / 10 5 20 30
SOCORRO......................... 79 50 73 46 / 5 10 10 10
SANDIA PARK/CEDAR CREST......... 71 43 66 39 / 10 10 20 30
TIJERAS......................... 73 43 68 42 / 10 10 20 30
MORIARTY/ESTANCIA............... 74 40 65 36 / 10 10 20 30
CLINES CORNERS.................. 70 42 64 37 / 10 10 20 30
GRAN QUIVIRA.................... 72 44 67 42 / 5 10 20 20
CARRIZOZO....................... 77 48 72 49 / 5 20 10 20
RUIDOSO......................... 73 47 69 41 / 10 20 10 30
CAPULIN......................... 74 43 67 42 / 5 20 5 20
RATON........................... 75 42 70 39 / 10 20 10 20
SPRINGER........................ 73 41 68 41 / 10 20 10 20
LAS VEGAS....................... 70 40 65 38 / 10 10 10 20
CLAYTON......................... 79 49 76 48 / 5 20 5 20
ROY............................. 76 47 71 44 / 10 20 10 20
CONCHAS......................... 77 49 76 51 / 10 10 5 20
SANTA ROSA...................... 80 50 78 47 / 10 10 5 20
TUCUMCARI....................... 84 53 81 51 / 10 20 5 20
CLOVIS.......................... 82 52 77 51 / 10 20 10 30
PORTALES........................ 84 53 79 55 / 10 20 10 40
FORT SUMNER..................... 84 52 80 51 / 10 20 5 20
ROSWELL......................... 86 54 83 52 / 10 20 5 30
PICACHO......................... 78 52 79 50 / 10 20 5 20
ELK............................. 72 51 73 48 / 10 20 10 20
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORMAN OK
1106 PM CDT WED MAY 13 2015
.AVIATION...
06Z TAFS... ANOTHER ROUND OF SHOWERS/STORMS WILL MOVE ACROSS THE
AREA OVERNIGHT/EARLY THU. CEILINGS WILL GRADUALLY IMPROVE
OVERNIGHT INTO THURSDAY. CEILINGS WILL THEN AGAIN LOWER THU
EVENING AS NEXT SYSTEM APPROACHES. SHOWERS/STORMS WILL BE POSSIBLE
AGAIN THU NIGHT.
&&
.PREV DISCUSSION... /ISSUED 856 PM CDT WED MAY 13 2015/
UPDATE...
MADE SOME ADJUSTMENTS TO THE PRECIP CHANCES THIS EVENING BASED ON
LATEST RADAR TRENDS. THOUGHT ABOUT CANCELLING THE FLASH FLOOD
WATCH... HOWEVER SOME OF THE HIGH RES MODELS KEEP THE CONVECTION
IN SOUTHWEST MOVING ACROSS THE AREA OVERNIGHT. WITH ANTECEDENT
CONDITIONS WOULD NOT TAKE MUCH ADDITIONAL RAINFALL TO CAUSE
ADDITIONAL FLOODING. THEREFORE WILL KEEP WATCH GOING FOR NOW.
OTHERWISE... NOT OTHER CHANGES AT THIS POINT.
PREV DISCUSSION... /ISSUED 615 PM CDT WED MAY 13 2015/
AVIATION...
0Z TAFS... IFR/LIFR CEILINGS WILL CONT THIS EVENING. CEILINGSWILL
LIKELY IMPROVE THURSDAY WITH EVERYONE EVENTUALLY AT MVFR/VFR
LEVELS. RAIN... HEAVY AT TIMES WILL CONTINUE TO MOVE ACROSS THE
REGION TONIGHT... GRADUALLY ENDING FROM WEST TO EAST. HOWEVER SOME
LOWERED VISIBILITIES WILL BE POSSIBLE THROUGH THU MORNING.
THUNDERSTORMS WILL ALSO BE POSSIBLE THIS EVENING.
PREV DISCUSSION... /ISSUED 412 PM CDT WED MAY 13 2015/
DISCUSSION...
PRIMARY PRECIPITATION SHIELD CONTINUES TO PIVOT EAST THROUGH
CENTRAL AND EASTERN PORTIONS OF THE COUNTY WARNING AREA...
ALTHOUGH CONVECTION IS REDEVELOPING IN THE TEXAS PANHANDLE AND
WEST TEXAS WHICH MAY MOVE INTO WESTERN PORTIONS OF THE AREA THIS
AFTERNOON AND EVENING AGAIN. HRRR AND OUNWRF SHOW THAT THIS MAY
PERSIST FOR A WHILE THIS EVENING IN WESTERN OKLAHOMA/NORTH TEXAS
BUT LIMITED INSTABILITY SHOULD PREVENT STORMS WIDESPREAD STORMS.
OVERALL... STILL EXPECT GENERAL DECREASE IN PRECIPITATION FROM
WEST TO EAST OVERNIGHT AND EARLY TOMORROW MORNING AS SHORTWAVE
MOVES NORTHEAST PAST THE AREA. FLASH FLOOD WATCH STILL LOOKS GOOD
AS THE MODERATE RAINFALL CAN STILL CAUSE FLOODING ISSUES BECAUSE
OF THE HEAVY RECENT RAINFALL.
STORMS EXPECTED AGAIN THURSDAY NIGHT INTO FRIDAY WITH MOISTURE
INCREASE AND PERHAPS A WEAK SHORTWAVE MOVING THROUGH THE AREA. THE
PRIMARY UPPER TROUGH APPROACHES AND INCREASES POPS SIGNIFICANTLY
FRIDAY NIGHT AND SATURDAY. DECENT SIGNAL OF A COMPLEX DEVELOPING
WEST AND MOVING INTO THE AREA SATURDAY MORNING WITH REDEVELOPMENT
EXPECTED AGAIN ON SATURDAY. THERE ARE STILL SOME QUESTIONS ON THE
EXPECTED EVOLUTION ON SATURDAY... BUT STILL WILL BE LOOKING AT THE
SEVERE WEATHER POTENTIAL FOR SATURDAY AS WE GET CLOSER.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 60 80 65 79 / 70 20 30 40
HOBART OK 58 80 62 81 / 70 10 40 30
WICHITA FALLS TX 61 82 65 82 / 40 10 40 40
GAGE OK 55 83 60 82 / 40 10 30 20
PONCA CITY OK 58 80 65 80 / 80 30 20 30
DURANT OK 63 81 66 79 / 50 40 30 50
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...FLASH FLOOD WATCH UNTIL 7 AM CDT THURSDAY FOR OKZ007-008-012-013-
017>020-022>048-050>052.
TX...FLASH FLOOD WATCH UNTIL 7 AM CDT THURSDAY FOR TXZ083>090.
&&
$$
30/25/25
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
341 AM MDT THU MAY 14 2015
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 300 AM MDT THU MAY 14 2015
FOG HAS FORMED OVER THE PAST FEW HOURS IN THE NORTH PLATTE VALLEY
AND ACROSS PORTIONS OF THE NEBRASKA PANHANDLE. WITH REALLY LIGHT
WINDS THE HRRR KEEPS LIFR CONDITIONS THRU 13Z SO INCLUDED SOME
PATCHY FOG INTO THE MID MORNING. OVERALL...SHOWER ACTIVITY WILL BE
QUITE A BIT LESS THIS AFTN COMPARED TO YESTERDAY. A SHORTWAVE
RIDGE WILL MOVE OVERHEAD THROUGH THE AFTN AND LLVL MOISTURE IS NOT
ALL THAT IMPRESSIVE. THE MODELS KEEP ISOLATED CONVECTION CONFINED
TO AREAS ALONG AND WEST OF THE LARAMIE RANGE THROUGH 00Z. UPPER
LEVEL DIVERGENCE WILL INCREASE AFTER 00Z AS A SHORTWAVE EJECTS
NORTHWARD ON THE EAST SIDE OF THE UPPER LOW OVER CALIFORNIA. WITH
GOOD MIDLVL ISENTROPIC ASCENT AND SOME ELEVATED CAPE...THIS IS
ACTUALLY A SITUATION WHERE SHOWER AND TSTM COVERAGE COULD BE
GREATER INTO THE NIGHT...ESPECIALLY OVER THE NORTHEASTERN HALF OF
THE CWA. THUS...KEPT THE 30-40 POPS GOING THROUGH EARLY FRI
MORNING. SOUTHEASTERLY SFC WINDS WILL CONTINUE TO ADVECT HIGHER
DEWPOINTS INTO THE PLAINS THROUGH THE NIGHT.
THE MOST IMPACTFUL EVENT IN THE SHORT TERM IS STILL LOOKING LIKE
THE CHANCE OF SEVERE STORMS ACROSS THE NEBRASKA PANHANDLE ON FRI.
OVER THE PAST FEW DAYS THE MODELS HAVE BEEN CONSISTENT AT SHOWING
THE COMBINATION OF INSTABILITY (CAPE VALUES OF 1500-1750 J/KG) AND
DEEP LAYER SHEAR (40-45 KTS) TO SUPPORT SUPERCELLS ALONG AND NORTH
OF THE WARM FRONT. THE MAIN QUESTION WILL BE JUST WHERE THE SFC
LOW AND ASSOCIATED WARM FRONT ARE LOCATED BY MIDDAY. TEND TO
PREFER THE NAM AND ECMWF SOLNS THAT INDICATE EAST WINDS CONTINUING
ACROSS MUCH OF THE PANHANDLE THRU THE AFTN...AS OPPOSED TO THE GFS
THAT PUSHES WESTERLY WINDS AND DRIER DEWPOINTS ACROSS THE ENTIRE
PANHANDLE BY 00Z. OF COURSE WILL ALSO HAVE TO WATCH AND SEE
WHETHER THE SFC LOW IS FURTHER WEST TOWARD THE LARAMIE RANGE AS
THIS WOULD PUSH THE SVR THREAT INTO SOUTHEAST WY. WHILE LARGE HAIL
WOULD LIKELY BE THE PRIMARY THREAT...THE LLVL SHEAR PARAMETERS DO
SHOW THE POTENTIAL FOR SOME WEAK TORNADOES ESPECIALLY ALONG AND
JUST NORTH OF THE WARM FRONT WHERE WINDS WILL BE BACKED THE MOST.
NAM HODOGRAPHS ARE PRETTY IMPRESSIVE WITH 0-3 KM HELICITY OF
250-300. LCL HEIGHTS ARE RATHER LOW ALSO. THE DAY 2 SPC OUTLOOK
HAS NOT CHANGED MUCH WITH MOST OF THE PANHANDLE IN A SLIGHT
RISK...AND THE ENHANCED RISK IS JUST OFF TO THE EAST INTO NORTH
PLATTES CWA. IT WILL DRY OUT QUICKLY BY FRI EVENING AS THE SFC LOW
AND WARM FRONT PUSH NORTHWARD INTO THE DAKOTAS. WITH QUITE A BIT
LESS LLVL MOISTURE AND INSTABILITY TO WORK WITH ON
SAT...CONVECTION WILL BE WEAKER AND LESS WIDESPREAD. THE UPPER
LEVEL SYSTEM WILL MOVE INTO THE CENTRAL PLAINS BY SAT NIGHT WITH A
COLD FRONT PUSHING ACROSS THE REGION.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 300 AM MDT THU MAY 14 2015
AN ACTIVE WEATHER PATTERN SHOULD PERSIST WITH LARGE SCALE
TROUGHING REMAINING INTACT OVER THE WESTERN CONUS. SOME LINGERING
SHOWERS AND TSTMS CAN BE EXPECTED ON SUN/SUN NIGHT AS A STRONG
/NEGATIVELY-TILTED MID-LEVEL SHORTWAVE LIFTS NORTHEAST INTO THE
DAKOTAS. THE PROJECTED TRACK OF THIS SYSTEM AND H7-H3 PROGS FROM
THE GFS/ECMWF SUGGEST THAT AREAS ALONG THE I80 CORRIDOR BETWEEN
CYS AND SNY WOULD SEE LESS PCPN WITH A POTENTIAL DRY SLOT ALOFT. A
TRANSITORY RIDGE WILL TEMPORARILY QUIET THINGS DOWN ON MON WITH
WEAK SUBSIDENCE AND SOME DRYING IN THE MID LEVELS. THE GFS HAS
COME INTO LINE WITH THE ECMWF ON TUE SHOWING WIDESPREAD LLVL
UPSLOPE DEVELOPING EAST OF THE LARAMIE RANGE AHEAD OF THE NEXT
SYSTEM LIFTING INTO THE DESERT SW. THE LATEST SUITE OF MEDIUM
RANGE MODEL GUIDANCE SHOWS QPF VALUES UP TO AN EXCEEDING ONE INCH
BETWEEN TUE NIGHT AND WED. THIS MAKES SENSE WITH LLVL FORCING
BENEATH INCREASINGLY DIFLUENT FLOW ALOFT AND A COUPLED H25 JET.
THE EURO IS CONSIDERABLY COLDER THAN THE GFS...SHOWING H7 TEMPS
FALLING TO BETWEEN -2 AND -4 DEG C BY 12Z WED. WHILE WARM
ADVECTION IN LLVL EASTERLY/UPSLOPE FLOW MAKES THIS QUESTIONABLE
AT THIS RANGE...WOULD NOT BE ENTIRELY SURPRISED TO SEE PCPN CHANGE
TO SNOW AT SOME POINT DURING THIS EVENT...AT LEAST FOR HIGHER
ELEVATIONS. POTENTIAL FOR CONVECTION WILL EXIST VIRTUALLY EVERY
DAY WITH SLIGHTLY NEGATIVE LIFTED INDEX VALUES EACH AFTN THROUGH
WED.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 214 AM MDT THU MAY 14 2015
AMENDED AVIATION DISCUSSION FOR 06Z TAFS. AREAS OF FOG ARE NOW
DEVELOPING OVER THE WESTERN NE PANHANDLE...WITH IFR CIGS/VSBYS
OVER SEVERAL TERMINALS. THE HRRR SHOWS THIS CONTINUING THROUGH
AT LEAST SUNRISE...LINGERING A BIT LONGER AT KAIA. VFR CONDITIONS
ARE EXPECTED OVER SOUTHEAST WYOMING SITES. SHOWERS AND TSTMS ARE
STILL EXPECTED ACROSS MUCH OF THE AREA LATER TODAY AND TONIGHT.
&&
.FIRE WEATHER...
ISSUED AT 300 AM MDT THU MAY 14 2015
NO FIRE WEATHER CONCERNS THROUGH THE WEEKEND. TODAY WILL BE THE
WARMEST DAY WITH MINIMUM AFTERNOON HUMIDITY VALUES FALLING TO
25-30 PERCENT AT SOME LOCATIONS. SHOWERS AND THUNDERSTORMS WILL
BECOME MORE WIDESPREAD BY LATE TONIGHT INTO FRIDAY AND COOLER
TEMPERATURES WILL OCCUR INTO THE WEEKEND. FUELS ARE ALSO IN FULL
GREEN UP AFTER THE RECENT WET PERIOD.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...ZF
LONG TERM...CLH
AVIATION...CLH
FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
216 AM MDT THU MAY 14 2015
.UPDATE...
ISSUED AT 906 PM MDT WED MAY 13 2015
AS OUR AFTERNOON FORECAST TEAM PREDICTED...SHOWERS HAVE DECREASED
CONSIDERABLY IN AREAL COVERAGE. BASED ON TRENDS AND 00Z MODEL
GUIDANCE...WILL MAINTAIN LOW CHANCES FOR PRECIPITATION THE REST
OF THE NIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 400 PM MDT WED MAY 13 2015
SHORTWAVE ENERGY AND UPPER LEVEL JET MAX WILL CONTINUE TO LIFT
NORTHEAST OUT OF THE FORECAST AREA THIS EVENING WITH MOST SHOWER
ACTIVITY ENDING WEST OF THE SHORTWAVE AND JET. A FEW SHOWERS MAY
LINGER PAST 9 PM BUT MOST ACTIVITY SHOULD HAVE ENDED BY THAT
TIME. TO THE WEST OF THE LARAMIE RANGE SHOWER ACTIVITY IS LARGELY
BEING DRIVEN BY INSTABILITY. THIS AREAS OF SHOWER ACTIVITY WILL
ALSO TAPER OFF THIS EVENING.
SUBSIDENCE WILL ALLOW SET IN THIS EVENING AS A RIDGE BUILDS OVER
THE NORTHERN ROCKIES. SKIES WILL CLEAR AND WINDS WILL BE ON THE
LIGHT SIDE TONIGHT. SOME POCKETS OF RADIATION FOG MAY DEVELOP LATE
TONIGHT. NOT EXPECTING LARGE IMPACTS FROM ANY FOG TONIGHT THAT
MIGHT FORM BUT IT WILL BE SOMETHING TO KEEP AN EYE ON LATE
TONIGHT...MAINLY WEST OF THE LARAMIE RANGE.
A BROAD WEST COAST TROUGH WILL BEGIN TO PUSH INTO THE ROCKIES LATE
TOMORROW AS THE RIDGE AXIS SHIFTS INTO THE PLAINS. A FEW SHOWERS
AND THUNDERSTORMS WILL DEVELOP THURSDAY AFTERNOON. THE SET UP IS
NOT SUPPORTIVE OF SEVERE THUNDERSTORMS BUT A FEW MARGINAL STORMS
NOT COMPLETELY QUESTION NEAR THE LARAMIE RANGE LATE AFTERNOON.
UPPER LEVEL ENERGY WITH ISENTROPIC FORCING WILL KEEP CHANCES FOR
SHOWERS AND A FEW THUNDERSTORMS GOING INTO THURSDAY NIGHT BUT THE
MAIN CHANCES FOR PRECIPITATION WILL HOLD OFF UNTIL FRIDAY. WILL
NEED TO KEEP A CLOSE EYE ON SEVERE THUNDERSTORM POTENTIAL INTO THE
PLAINS FRIDAY. THERE IS STILL A LOT OF UNCERTAINLY IN THE
PLACEMENT OF A WARM FRONT AND TIMING OF COLD FRONT FRIDAY. MODELS
ARE SHOWING A LOT OF ELEVATED CAPE AND ENOUGH SHEAR FOR SUPERCELL
THUNDERSTORMS. NORTH OF THE WARM FRONT LARGE HAIL WILL BE THE MAIN
SEVERE THUNDERSTORM THREAT BUT ALONG AND CLOSE TO THE SURFACE WARM
FRONT THERE WILL LIKELY BE AN ELEVATED TORNADO THREAT. WILL
CONTINUE TO MONITOR MODEL CHANGES BUT AT THIS TIME IT LOOKS AT
THROUGH THE SURFACE FRONT WILL EXTEND ACROSS THE NORTHERN NEBRASKA
PANHANDLE FRIDAY AFTERNOON.
.LONG TERM...SATURDAY THROUGH TUESDAY...
ISSUED AT 400 PM MDT WED MAY 13 2015
MEDIUM RANGE MODELS ARE IN GENERAL AGREEMENT WITH LARGELY MERIDIONAL
FLOW ALOFT THROUGH THE PERIOD. THIS SHOULD RESULT IN A FAIRLY ACTIVE
WEATHER PERIOD FOR SOUTHEAST WYO AND THE WESTERN NEB PANHANDLE THRU
THE WEEKEND AND INTO EARLY NEXT WEEK. THE WEEKEND STILL APPEARS TO
BE RATHER WET WITH A COMPLEX NEGATIVELY TILTED SHORTWAVE MOVING EAST
ONTO THE PLAINS ON SAT. BOTH THE GFS AND ECMWF BRING AN ASSOCIATED
DOUBLE-BARRELED SURFACE LOW INTO SD/NE...WITH WRAPAROUND PCPN
LIKELY SPREADING ACROSS THE CWA. WEAK CAPES SUGGEST CONVECTION
WILL BE AT A MINIMUM...BUT COOL AIR ALOFT MAY YIELD ENOUGH
INSTABILITY FOR A FEW LIGHTNING STRIKES AND POSSIBLY SMALL HAIL.
THERE IS SOME POTENTIAL FOR ACCUMULATING SNOWFALL IN THE HIGH
MOUNTAINS ABOVE 9K FEET ON SAT AND SUN WITH FAVORABLE OROGRAPHICS
AND H7 TEMPS FALLING TO -2 DEG C OR LOWER PER THE ECMWF. EXPECT
THIS TO BE SUB-ADVISORY. A TRANSITORY RIDGE PROVIDES A BRIEF BREAK
ON SUN NIGHT INTO MON BEFORE STRONG SW FLOW ALOFT INCREASES AGAIN
AHEAD OF THE NEXT SYSTEM OVER SOUTHERN CALIFORNIA. SOME
DIFFERENCES IN MODEL QPF/PCPN COVERAGE HEADING INTO TUES...WITH
THE ECMWF SHOWING MUCH MORE WIDESPREAD SHOWERS AND TSTMS WITH LLVL
UPSLOPE DEVELOPING ALONG THE LARAMIE RANGE. THE GFS TURNS WINDS
WESTERLY/DOWNSLOPE AS IT MOVES THE SURFACE TROUGH QUICKLY INTO
WESTERN NEB. INCREASED POPS ABOVE GUIDANCE WITH BOTH THE GFS AND
ECM SHOWING STRONG UPPER DIFFLUENCE. WOULD TEND TO LEAN TOWARD
THE ECMWF WITH SOUTHERLY MID/UPPER-LEVEL FLOW KEEPING THE SURFACE
FEATURE TIED TO THE LARAMIE RANGE AS WELL. BOTH MODELS SUGGEST
UPWARDS OF 1500 J/KG OF CAPE ON THE EAST SIDE OF THE BOUNDARY...SO
THE POTENTIAL FOR STRONG CONVECTION SHOULD BE ON THE UPTICK COME
TUE AFTN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 214 AM MDT THU MAY 14 2015
AMENDED AVIATION DISCUSSION FOR 06Z TAFS. AREAS OF FOG ARE NOW
DEVELOPING OVER THE WESTERN NE PANHANDLE...WITH IFR CIGS/VSBYS
OVER SEVERAL TERMINALS. THE HRRR SHOWS THIS CONTINUING THROUGH
AT LEAST SUNRISE...LINGERING A BIT LONGER AT KAIA. VFR CONDITIONS
ARE EXPECTED OVER SOUTHEAST WYOMING SITES. SHOWERS AND TSTMS ARE
STILL EXPECTED ACROSS MUCH OF THE AREA LATER TODAY AND TONIGHT.
&&
.FIRE WEATHER...
ISSUED AT 331 PM MDT WED MAY 13 2015
CONDITIONS WILL REMAIN ON THE COOL SIDE OF AVERAGE OVER THE NEXT 7 DAYS
AS AN ACTIVE WEATHER PATTERN REMAINS IN PLACE. THERE WILL BE A CHANCE
FOR SHOWERS AND A FEW THUNDERSTORMS SEVERAL DAYS DURING THIS PERIOD.
THERE ARE NO CRITICAL FIRE CONCERNS.
&&
.HYDROLOGY...
ISSUED AT 331 PM MDT WED MAY 13 2015
THE LARAMIE RIVER NEAR LARAMIE WILL CONTINUE TO RUN HIGH THE NEXT
SEVERAL DAYS...BUT ASSUMING FORECAST PRECIPITATION AMOUNTS ARE
CLOSE TO CORRECT...THEN THE RIVER WILL REMAIN BELOW FLOOD STAGE.
TEMPERATURES WILL REMAIN AT TO BELOW NORMAL OVER THE NEXT
WEEK...SO AS LONG AND STRONG THUNDERSTORMS DO NOT OCCUR OVER THE
MOUNTAINS...SNOW PACK WILL SLOWLY COME OFF THE MOUNTAINS WITH NO
BIG CONCERNS FOR RIVER FLOODING OVER THE NEXT WEEK.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
UPDATE...RUBIN
SHORT TERM...SML
LONG TERM...CAH
AVIATION...CLH
FIRE WEATHER...SML
HYDROLOGY...SML
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
433 AM PDT THU MAY 14 2015
.SYNOPSIS...A SYSTEM TO OUR WEST WILL PRODUCE SHOWERS AND POSSIBLE
THUNDERSTORMS TODAY INTO THE EVENING ESPECIALLY FOR LOCATIONS
SOUTH OF SAN FRANCISCO. A FEW SHOWERS MAY LINGER INTO FRIDAY
MORNING. DRY WEATHER WILL RETURN BY FRIDAY AFTERNOON AND WILL
LIKELY CONTINUE THROUGH THE WEEKEND AND WELL INTO NEXT WEEK.
COOLER THAN NORMAL TEMPERATURES WILL CONTINUE.
&&
.DISCUSSION...AS OF 3:00 AM PDT THURSDAY...KMUX RADAR THIS MORNING
IS STARTING TO PICK UP THE LEADING EDGE OF PRECIPITATION FROM A
SYSTEM OFF OUR COAST. CLOSEST ECHOES AROUND ABOUT 70 MILES TO THE
WEST OF MONTEREY WITH MORE SUBSTANTIAL RETURNS ABOUT 75 MILES WEST
OF BIG SUR. THIS VERIFIES WELL WITH THE LATEST RUN OF THE HRRR.
MODELS ARE GENERALLY IN GOOD AGREEMENT THAT RAIN WILL CONTINUE TO
ADVANCE TO THE COAST THIS MORNING AND BE NEAR LOCAL BEACHES BY MID
TO LATE MORNING. BY EARLY AFTERNOON RAIN IS EXPECTED TO BE ACROSS
OUR ENTIRE AREA. RAIN WILL ALSO CHANGE OVER TO SHOWERS BY
AFTERNOON AS THE ATMOSPHERE BECOMES MORE UNSTABLE. LIFTED VALUES
DROP AS LOW AS MINUS 2 ALONG WITH SOME WEAK CAPE NUMBERS SO
THUNDERSTORMS AND SMALL HAIL CANNOT BE RULED OUT.
RAINFALL AMOUNTS ARE STILL EXPECTED TO BE HIGHER THE FARTHER TO
THE SOUTH YOU TRAVEL WITH THE HIGHEST VALUES FOR COASTAL MONTEREY
COUNTY MOUNTAINS. THERE HALF AN INCH TO AN INCH COULD EASILY FALL.
FOR THE REST OF OUR AREA...MANY PLACES WILL LIKELY SEE A TENTH TO
A QUARTER OF AN INCH. INTERESTING TO NOTE OFF THE HRRR THAT IT
INDICATES SOME POCKETS OF HALF AN INCH TO THE EAST BY BY THE
AFTERNOON. AS IS ALWAYS THE CASE WITH SHOWERS...WE WILL LIKELY SEE
A FEW SPOTS GETTING MUCH MORE THAN EXPECTED WHILE OTHER PLACES GET
LITTLE TO NO RAINFALL. SHOWERS WILL LINGER INTO THE OVERNIGHT
HOURS AND SLOWLY DIMINISH THROUGH FRIDAY.
SYNOPTICALLY THE SYSTEM THAT WILL PROVIDE THE RAIN IS ASSOCIATED
WITH A LONGWAVE TROF THAT IS DIVING SOUTHWARD OFF THE WEST COAST.
BASED OFF THE TRACK OF THE PARENT LOW ASSOCIATED WITH THE TROF THE
NEXT ROUND OF RAIN WILL FOCUS WELL TO OUR SOUTH. PERSONS WHO HAVE
TRAVEL PLANS TO SOUTHERN CALIFORNIA ON FRIDAY SHOULD PAY VERY
CLOSE ATTENTION TO THE LATEST FORECASTS.
A MIX OF SUN AND CLOUDS ALONG WITH COOLER THAN NORMAL TEMPERATURES
WILL LIKELY GO THROUGH THE WEEKEND INTO ALL OF NEXT WEEK AS A
BROAD LONGWAVE TROF REMAINS ACROSS OUR ENTIRE REGION. MULTIPLE
DISTURBANCES WILL ROTATE THROUGH THE TROF ALTHOUGH THE VAST
MAJORITY OF ASSOCIATED RAINFALL WITH LIKELY STAY WELL OUT OF OUR
CWA. ON THE FLIP SIDE...THE UNSETTLED PATTERN WILL HELP TO LIMIT
THE MARINE LAYER.
&&
.AVIATION...AS OF 4:30 AM PDT THURSDAY...CLOUDS ARE LOWERING WITH
THE APPROACH OF AN UPPER LEVEL LOW. RADAR IS STARTING TO DETECT
LIGHT SHOWERS OFF THE COAST AND THESE WILL MOVE INTO THE COAST BY
MIDMORNING AND INLAND LATE MORNING. WINDS WILL BE LIGHT SOUTHERLY
THIS MORNING BUT WILL SWITCH TO WESTERLY IN THE AFTERNOON.
VICINITY OF KSFO...MVFR CIGS. SHOWERS AFTER 16Z. SOUTHEAST WINDS
5-10 KT SWITCHING TO THE WEST AFTER 20Z. CLOUDS DECREASING AFTER 02Z.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...MVFR CIGS. SHOWERS AFTER 15Z. CLOUDS
DECREASING AFTER 01Z.
&&
.MARINE...AS OF 4:30 AM PDT THURSDAY...A 1010 MB LOW OFF THE
NORTHERN CALIFORNIA COAST WILL TRACK SOUTHWARD BRINGING A SLIGHT
CHANCE OF THUNDERSTORMS TODAY AND TONIGHT. NORTHWEST WINDS WILL
INCREASE FRIDAY AND SATURDAY AS THE LOW MOVES INLAND OVER SOUTHERN
CALIFORNIA AND HIGH PRESSURE BUILDS OFF THE CALIFORNIA COAST.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...NONE.
$$
PUBLIC FORECAST: BELL
AVIATION/MARINE: W PI
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AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
259 AM PDT THU MAY 14 2015
.SYNOPSIS...A SYSTEM TO OUR WEST WILL PRODUCE SHOWERS AND POSSIBLE
THUNDERSTORMS TODAY INTO THE EVENING ESPECIALLY FOR LOCATIONS
SOUTH OF SAN FRANCISCO. A FEW SHOWERS MAY LINGER INTO FRIDAY
MORNING. DRY WEATHER WILL RETURN BY FRIDAY AFTERNOON AND WILL
LIKELY CONTINUE THROUGH THE WEEKEND AND WELL INTO NEXT WEEK.
COOLER THAN NORMAL TEMPERATURES WILL CONTINUE.
&&
.DISCUSSION...AS OF 3:00 AM PDT THURSDAY...KMUX RADAR THIS MORNING
IS STARTING TO PICK UP THE LEADING EDGE OF PRECIPITATION FROM A
SYSTEM OFF OUR COAST. CLOSEST ECHOES AROUND ABOUT 70 MILES TO THE
WEST OF MONTEREY WITH MORE SUBSTANTIAL RETURNS ABOUT 75 MILES WEST
OF BIG SUR. THIS VERIFIES WELL WITH THE LATEST RUN OF THE HRRR.
MODELS ARE GENERALLY IN GOOD AGREEMENT THAT RAIN WILL CONTINUE TO
ADVANCE TO THE COAST THIS MORNING AND BE NEAR LOCAL BEACHES BY MID
TO LATE MORNING. BY EARLY AFTERNOON RAIN IS EXPECTED TO BE ACROSS
OUR ENTIRE AREA. RAIN WILL ALSO CHANGE OVER TO SHOWERS BY
AFTERNOON AS THE ATMOSPHERE BECOMES MORE UNSTABLE. LIFTED VALUES
DROP AS LOW AS MINUS 2 ALONG WITH SOME WEAK CAPE NUMBERS SO
THUNDERSTORMS AND SMALL HAIL CANNOT BE RULED OUT.
RAINFALL AMOUNTS ARE STILL EXPECTED TO BE HIGHER THE FARTHER TO
THE SOUTH YOU TRAVEL WITH THE HIGHEST VALUES FOR COASTAL MONTEREY
COUNTY MOUNTAINS. THERE HALF AN INCH TO AN INCH COULD EASILY FALL.
FOR THE REST OF OUR AREA...MANY PLACES WILL LIKELY SEE A TENTH TO
A QUARTER OF AN INCH. INTERESTING TO NOTE OFF THE HRRR THAT IT
INDICATES SOME POCKETS OF HALF AN INCH TO THE EAST BY BY THE
AFTERNOON. AS IS ALWAYS THE CASE WITH SHOWERS...WE WILL LIKELY SEE
A FEW SPOTS GETTING MUCH MORE THAN EXPECTED WHILE OTHER PLACES GET
LITTLE TO NO RAINFALL. SHOWERS WILL LINGER INTO THE OVERNIGHT
HOURS AND SLOWLY DIMINISH THROUGH FRIDAY.
SYNOPTICALLY THE SYSTEM THAT WILL PROVIDE THE RAIN IS ASSOCIATED
WITH A LONGWAVE TROF THAT IS DIVING SOUTHWARD OFF THE WEST COAST.
BASED OFF THE TRACK OF THE PARENT LOW ASSOCIATED WITH THE TROF THE
NEXT ROUND OF RAIN WILL FOCUS WELL TO OUR SOUTH. PERSONS WHO HAVE
TRAVEL PLANS TO SOUTHERN CALIFORNIA ON FRIDAY SHOULD PAY VERY
CLOSE ATTENTION TO THE LATEST FORECASTS.
A MIX OF SUN AND CLOUDS ALONG WITH COOLER THAN NORMAL TEMPERATURES
WILL LIKELY GO THROUGH THE WEEKEND INTO ALL OF NEXT WEEK AS A
BROAD LONGWAVE TROF REMAINS ACROSS OUR ENTIRE REGION. MULTIPLE
DISTURBANCES WILL ROTATE THROUGH THE TROF ALTHOUGH THE VAST
MAJORITY OF ASSOCIATED RAINFALL WITH LIKELY STAY WELL OUT OF OUR
CWA. ON THE FLIP SIDE...THE UNSETTLED PATTERN WILL HELP TO LIMIT
THE MARINE LAYER.
&&
.AVIATION...AS OF 10:53 PM PDT WEDNESDAY...A MIX OF LOW, MID AND
HIGH CLOUDS WILL CONTINUE TO MOVE ACROSS THE REGION WITH AN
INCREASING CHANCE OF RAIN LATE TONIGHT INTO EARLY THURSDAY
MORNING. A FRONTAL BAND ASSOCIATED WITH THE APPROACHING LOW
WILL ARRIVE PARALLEL TO THE COAST THEN SWEEP ACROSS THE REGION
THURSDAY MORNING BRINGING RAIN TO THE ENTIRE AREA. WET RUNWAYS ARE
POSSIBLE AFTER 12Z THURSDAY.
VICINITY OF KSFO...VFR CIGS WILL LOWER TO AROUND 3000 FEET
OVERNIGHT WITH RAIN CHANCES INCREASING AFTER 12Z TONIGHT. LIGHT
SOUTHWESTERLY WINDS OF 5 TO 10 KT EXPECTED THROUGH LATE TONIGHT.
WINDS WILL TURN SOUTHERLY OVERNIGHT INTO THURSDAY. WET RUNWAYS
POSSIBLE AFTER 12Z.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...VFR CIGS WILL LOWER TO AROUND 2500
FEET OVERNIGHT WITH RAIN CHANCES INCREASING AFTER 15Z TONIGHT.
LIGHT SOUTHWESTERLY WINDS OF 5 TO 10 KT EXPECTED THROUGH LATE
TONIGHT. WINDS WILL TURN SOUTHERLY OVERNIGHT INTO THURSDAY. WET
RUNWAYS POSSIBLE AFTER 15Z.
&&
.MARINE...AS OF 9:07 PM PDT WEDNESDAY...LIGHT SOUTHERLY WINDS WILL
CONTINUE TONIGHT AS A LOW PRESSURE SYSTEM APPROACHES THE AREA. A
SLIGHT CHANCE OF THUNDERSTORMS EXISTS THURSDAY AS THIS STORM MOVES
ACROSS THE COASTAL WATERS. STRONGER NORTHWEST WINDS RETURN LATE IN
THE WEEK AND INTO THE WEEKEND AS HIGH PRESSURE REDEVELOPS OVER THE
REGION.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...NONE.
$$
PUBLIC FORECAST: BELL
AVIATION/MARINE: CW
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AREA FORECAST DISCUSSION
NWS TAUNTON MA
1003 AM EDT THU MAY 14 2015
.SYNOPSIS...
LARGE HIGH PRESSURE WILL BUILD ACROSS THE EASTERN U.S. WITH DRIER
WEATHER THROUGH THE REMAINDER OF THIS WEEK. AN UPPER LEVEL
DISTURBANCE WILL BRING SHOWERS TO THE REGION FRIDAY NIGHT AND
SATURDAY. A BACK DOOR COLD FRONT USHERS IN COOLER AIR SUNDAY
THROUGH THE BEGINNING OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
10 AM UPDATE...
MINOR CHANGES TO THE FORECAST. WENT WITH A HRRR / RAP BLEND FOR
THE NEXT 12-HOURS WITH RESPECT TO TEMPERATURES / DEWPOINTS / WIND
THAT NETS HIGHS AROUND THE UPPER-60S TO LOW-70S WITH MINIMUM
RELATIVE HUMIDITY VALUES DOWN AROUND 20-PERCENT. HIGH PRESSURE IN
CONTROL RESULTING IN LIGHT WINDS WHICH WILL ALLOW SEABREEZES TO
COME ASHORE BY MIDDAY...PUSHING INTO THE EASTERN- INTERIOR BY
EVENING. WINDS OVERALL REMAINING LIGHT...EXPECTING THE STRONGEST
ALONG THE COASTS WITH ONSHORE FLOW...GUSTS AROUND 15 MPH POSSIBLE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT...
ANOTHER GOOD RADIATIONAL COOLING NIGHT WITH LIGHT WINDS AND CLEAR
SKIES AS HIGH PRES REMAINS IN CONTROL. MINS WILL LIKELY DROP INTO
THE MID/UPPER 30S WITH PATCHY FROST IN THE NORMALLY COLDER
LOCATIONS IN W MA AND INTERIOR E MA AND FROST ADVISORIES MAY BE
NEEDED AGAIN. ELSEWHERE LOWS WILL BE MOSTLY IN THE 40S.
FRIDAY...
HIGH PRES WILL BE S OF NEW ENG WITH DEVELOPING SW FLOW BRINGING
MILDER AIR TO SNE. 850 MB TEMPS WARMING TO 7-8C WHICH TRANSLATES
TO HIGHS IN THE LOW TO MID 70S...BUT COOLER ALONG THE COAST WHERE
SEABREEZES LIKELY AGAIN. SUNSHINE WILL GIVE WAY TO INCREASING HIGH
CLOUDS IN THE AFTERNOON.
&&
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
HIGHLIGHTS...
* RAIN LATE FRI INTO THE WEEKEND WITH SHORTWAVE
* BACK DOOR COLD FRONT WILL BRING COOLER TEMPERATURES SUN AND MON
* COLD FRONT MAY BRING ANOTHER ROUND OF SHOWERS TOWARDS MIDWEEK
MODELS ARE IN DECENT AGREEMENT THROUGH THE LONG TERM PERIOD. AS WE
MOVE INTO THE WEEKEND SHORTWAVE WILL MOVE THROUGH SOUTHERN NEW
ENGLAND BRINGING RAIN SHOWERS TO THE REGION. AN UPPER LEVEL RIDGE
THEN BUILDS OVER THE REGION AND A BACK DOOR COLD FRONT WILL MOVE
INTO SOUTHERN NEW ENGLAND SUNDAY. THE EXACT TIMING AND
SOUTHWESTWARD EXTENT OF THE FRONT IS IN QUESTION WITH THE ECMWF
BRINGING IT MUCH FARTHER SOUTHWEST THAN THE GFS. THIS WILL MAKE A
BIG DIFFERENCE IN HIGH TEMPERATURES. BEYOND THE BACK DOOR COLD
FRONT...THERE ARE TIMING DISCREPANCIES AMONGST THE MODELS.
FRIDAY NIGHT AND SATURDAY...THIS PERIOD LOOKS TO HAVE SOME RAIN
SHOWERS AS A SHORTWAVE DISTURBANCE MOVES OVER SOUTHERN NEW ENGLAND.
THERE IS SOME MODEST INSTABILITY DURING THIS TIME FRAME AS INDICATED
BY K INDICES ABOVE 30 AND NEGATIVE SHOWALTER INDICES. THIS COULD
RESULT IN SOME ISOLATED THUNDER WITH THESE SHOWERS.
SUNDAY...A BACK DOOR COLD FRONT WILL PUSH INTO SOUTHERN NEW
ENGLAND...BRINGING AN END TO THE RAIN SHOWERS. AS MENTIONED
ABOVE...THE WESTWARD EXTENT OF THIS FRONT DEPENDS ON THE MODEL
MAKING TEMPERATURE FORECASTS DIFFICULT. EXPECT SUNDAY TO BE A DRY
DAY WITH CHILLY NORTHEAST WINDS ALONG THE EAST COAST AND
PARTICULARLY ACROSS NORTHEASTERN MASSACHUSETTS. TEMPERATURE
FORECAST IS LOW CONFIDENCE...PARTICULARLY ACROSS EASTERN MASS AND
RHODE ISLAND.
MONDAY THROUGH WEDNESDAY...THERE ARE TIMING DISCREPANCIES AMONGST
THE MODELS BUT THE OVERALL PATTERN IS SIMILAR BETWEEN THE SOLUTIONS.
THE UPPER RIDGE OVER NEW ENGLAND WILL WEAKEN AND GRADUALLY MOVE
OFFSHORE LATE MONDAY INTO TUESDAY. THEN LOW PRESSURE MOVING THROUGH
QUEBEC WILL BRING A COLD FRONT THROUGH SOUTHERN NEW ENGLAND
TUESDAY OR WEDNESDAY ALLOWING FOR ANOTHER CHANCE OF SHOWERS.
TEMPERATURES WILL BE RIGHT AROUND NORMAL DURING THIS TIME FRAME.
&&
.AVIATION /14Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
THROUGH FRIDAY...VFR. ONSHORE SEABREEZES DEVELOPING AROUND 15Z.
KBOS TAF...HIGH CONFIDENCE IN TAF.
KBDL TAF...HIGH CONFIDENCE IN TAF.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...
FRIDAY NIGHT THROUGH SATURDAY...MODERATE CONFIDENCE. MAINLY VFR.
PERIODS OF MVFR/IFR IN SCATTERED SHOWERS AND FOG.
SUNDAY...MODERATE CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF MVFR
CONDITIONS BEHIND BACK DOOR COLD FRONT.
MONDAY...HIGH CONFIDENCE. VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH FRIDAY/...HIGH CONFIDENCE.
TODAY THROUGH FRIDAY...HIGH PRES WILL BRING QUIET BOATING
WEATHER WITH LIGHT WINDS AND SEAS AND GOOD VSBYS. WINDS WILL
BECOME ONSHORE 10-15 KTS OVER NEARSHORE WATERS TODAY AND AGAIN FRI
AS SEABREEZES DEVELOP.
OUTLOOK...FRIDAY NIGHT THROUGH MONDAY...
FRIDAY NIGHT AND SATURDAY...LOW CONFIDENCE. WHILE CONDITIONS ARE
CURRENTLY EXPECTED TO REMAIN BELOW SMALL CRAFT CRITERIA...WINDS AND
SEAS WILL BE INCREASING AS A COLD FRONT APPROACHES THE WATERS. 5
FOOT SEAS IN PARTICULAR ARE NOT OUT OF THE QUESTION FOR THE OUTER
WATERS.
SUNDAY AND MONDAY...MAINLY QUIET BOATING WEATHER AS HIGH PRESSURE
BUILDS SOUTH OVER THE WATERS. NORTHEASTERLY WINDS SUNDAY WILL
GRADUALLY BECOME LIGHT AND VARIABLE.
&&
.FIRE WEATHER...
TODAY AND FRIDAY...DRY WEATHER CONDITIONS WILL CONTINUE WITH
MINIMUM RH VALUES AWAY FROM THE IMMEDIATE COAST DROPPING TO UPPER
TEENS TO 20S TODAY AND 20-30 PERCENT FRIDAY. SINCE HIGH PRESSURE
WILL BE OVERHEAD...WINDS WILL BE LIGHT WITH SPEEDS LESS THAN 15
MPH.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...FROST ADVISORY FROM 2 AM TO 7 AM EDT FRIDAY FOR MAZ002-003-008-
010.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KJC/RLG
NEAR TERM...KJC/RLG/SIPPRELL
SHORT TERM...KJC
LONG TERM...RLG
AVIATION...KJC/RLG
MARINE...KJC/RLG
FIRE WEATHER...WFO BOX STAFF
AREA FORECAST DISCUSSION...UPDATED
NWS TAMPA BAY RUSKIN FL
1002 AM EDT THU MAY 14 2015
.UPDATE...
ANOTHER WARM AND MUGGY DAY EXPECTED ACROSS WEST-CENTRAL AND
SOUTHWEST FLORIDA. EARLY MORNING VISIBLE SATELLITE IMAGERY SHOWS
MOSTLY CLEAR SKIES THIS MORNING WITH ONLY A FEW HIGH CLOUDS PRESENT
ACROSS THE AREA. WITH MOSTLY CLEAR SKIES...TEMPS WILL WARM
QUICKLY INTO THE MIDDLE/UPPER 80S BEFORE ULTIMATELY TOPPING OUT
IN THE LOWER 90S FOR MUCH OF THE AREA...SLIGHTLY COOLER ALONG THE
IMMEDIATE COAST.
AS FAR AS RAIN CHANCES ARE CONCERNED...THE OVERALL SETUP FOR TODAY
LOOKS SIMILAR TO YESTERDAY. WITH DECENT SE/E FLOW IN PLACE IN THE
LOWER LEVELS WEST COAST SEA BREEZE WILL LIKELY HAVE A DIFFICULT TIME
PENETRATING TOO FAR INLAND TODAY. LOCAL HI-RES MODELS SUPPORT THIS
THINKING OF A LIKELY SEA BREEZE COLLISION NEAR THE I-75 CORRIDOR.
MOST RECENT HRRR RUN IS NOT VERY ROBUST WITH OVERALL PRECIP COVERAGE
NOR ARE RECENT RUNS OF CONVECTION ALLOWING MODELS SO MAINTAINING
POPS IN THE 30 TO 50 RANGE FOR THE AREA...HIGHEST NEAR AND WEST
OF I-75...SEEMS REASONABLE. ONLY MADE A FEW MINOR ADJUSTMENTS FOR
THE MORNING UPDATE.
&&
.AVIATION...
VFR CONDITIONS EXPECTED TO PREVAIL THIS MORNING AND INTO THE
AFTERNOON. EASTERLY FLOW THROUGH THE MORNING HOURS WILL GIVE WAY
TO AN AFTERNOON WEST COAST SEA BREEZE FOR COASTAL TERMINALS. VCTS
DEVELOPING DURING THE LATE AFTERNOON HOURS WILL AFFECT TAFS SITES
INTO THE EVENING BEFORE STORM COVERAGE DISSIPATES AFTER SUNSET.
LOCALIZED MVFR/IFR RESTRICTIONS WILL BE POSSIBLE WITH ANY
THUNDERSTORMS BUT WILL NOT INCLUDE ANY TEMPOS AT THIS TIME.
&&
.MARINE...
SURFACE RIDGING CENTERED WELL NORTH OF THE AREA WILL HELP MAINTAIN
GENERALLY EASTERLY FLOW. EXPECT A SEA BREEZE CIRCULATION TO DEVELOP
EACH AFTERNOON NEAR THE COAST WITH A NOCTURNAL EASTERLY SURGE
THROUGH THE WEEKEND. SCATTERED SHOWERS AND STORMS NEAR THE COAST ARE
EXPECTED TO SHIFT INTO THE NEAR AND OFF SHORE WATERS DURING THE LATE
EVENING HOURS AS THE LAND BREEZE DEVELOPS. NO CHANGES NEEDED FOR THE
MORNING UPDATE.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 90 73 89 72 / 50 40 50 50
FMY 91 71 91 71 / 40 20 40 30
GIF 91 71 90 71 / 40 10 50 10
SRQ 89 71 88 71 / 50 40 50 50
BKV 91 70 88 69 / 50 20 50 20
SPG 90 75 89 75 / 40 40 50 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE/AVIATION/FIRE WEATHER/MARINE...11/MCKAUGHAN
DECISION SUPPORT...14/MROCZKA
AREA FORECAST DISCUSSION
NWS LINCOLN IL
953 AM CDT THU MAY 14 2015
.UPDATE...
ISSUED AT 952 AM CDT THU MAY 14 2015
SHOWERS IN WEST CENTRAL ILLINOIS HAVE BEEN STRUGGLING TO MAKE ANY
EASTWARD PROGRESS. OUR MORNING SOUNDING SHOWED VERY DRY AIR BELOW
15000 FEET...AND CEILINGS UNDERNEATH THE RAIN SHIELD ARE
STRUGGLING TO GET MUCH BELOW 7000 FEET. RAP FORECAST SOUNDINGS
KEEP IT PRETTY DRY BELOW 850 MB INTO THE AFTERNOON AND FOCUS MUCH
OF THE RAIN ALONG AND WEST OF THE ILLINOIS RIVER. THIS WOULD BE
ASSOCIATED WITH THE SHOWERS THAT ARE CURRENTLY STEADILY MOVING
THROUGH CENTRAL AND SOUTHWEST MISSOURI. THE RADAR ECHOES MOVING
OUT OF SOUTHWEST ILLINOIS ARE ALSO VERY LIGHT...AND THESE WILL BE
MOVING INTO THE SOUTHEAST PART OF THE FORECAST AREA SHORTLY AFTER
MIDDAY.
HAVE SENT SOME UPDATED ZONES/GRIDS TO MAINLY REFINE THE RAIN
TRENDS.
&&
.SHORT TERM...(TODAY)
ISSUED AT 319 AM CDT THU MAY 14 2015
1030MB HIGH CENTERED OVER THE EASTERN GREAT LAKES CONTINUES TO
CONTROL THE WEATHER ACROSS CENTRAL ILLINOIS EARLY THIS
MORNING...RESULTING IN COOL/DRY CONDITIONS WITH 07Z/2AM TEMPERATURES
MAINLY IN THE UPPER 40S AND LOWER 50S. AIRMASS IS QUITE DRY...AS
EVIDENCED BY THE 00Z KILX UPPER AIR SOUNDING AND CURRENT SURFACE
DEWPOINTS IN THE LOWER 40S. SHORT-WAVE TROUGH SHOWN ON LATEST WATER
VAPOR IMAGERY OVER KANSAS/OKLAHOMA WILL LIFT NORTHWARD
TODAY...SPREADING CLOUDS AND SHOWERS INTO PORTIONS OF CENTRAL
ILLINOIS. DUE TO THE VERY DRY AIR INITIALLY IN PLACE...THINK MODELS
ARE STILL TOO FAST IN BRINGING THE PRECIP INTO THE AREA. HAVE
THEREFORE SLOWED ITS NORTHEASTWARD SPREAD...WITH LOCATIONS
ALONG/EAST OF A BLOOMINGTON TO EFFINGHAM LINE REMAINING DRY UNTIL
EARLY AFTERNOON AT THE EARLIEST. AREAS ALONG THE INDIANA BORDER
WILL LIKELY STAY DRY FOR THE ENTIRE DAY. FURTHER WEST...RAIN
CHANCES INCREASE TO LIKELY ALONG/NORTHWEST OF THE ILLINOIS RIVER BY
AFTERNOON. DUE TO EXTENSIVE CLOUD COVER AND E/SE WINDS...HAVE GONE
SLIGHTLY BELOW MAV GUIDANCE FOR HIGHS TODAY...WITH READINGS
GENERALLY IN THE MIDDLE TO UPPER 60S...EXCEPT LOWER 70S ALONG/SOUTH
OF I-70 WHERE A FEW PEEKS OF SUNSHINE WILL BE POSSIBLE.
.LONG TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 319 AM CDT THU MAY 14 2015
UPPER WAVE WILL TRACK FROM MINNESOTA/IOWA THIS EVENING INTO THE
GREAT LAKES BY FRIDAY MORNING...KEEPING RAIN CHANCES ALIVE ACROSS
MUCH OF CENTRAL ILLINOIS. HIGHEST POPS WILL BE FOCUSED IN CLOSER
PROXIMITY TO THE STRONGEST FORCING FROM THE PEORIA AND
BLOOMINGTON AREAS NORTHWARD...TAPERING DOWN TO JUST SLIGHT CHANCES
ALONG/SOUTH OF I-70. FORECAST SOUNDINGS ARE INITIALLY QUITE
STABLE...HOWEVER MODEST ELEVATED INSTABILITY DEVELOPS OVERNIGHT
WITH MUCAPE VALUES APPROACHING 1000J/KG. WILL THEREFORE MENTION A
CHANCE OF THUNDER ACROSS THE BOARD TONIGHT.
ONCE THE WAVE EXITS...UPPER HEIGHTS RISE AND OVERALL FORCING FOR
ADDITIONAL CONVECTION WANES FOR BOTH FRIDAY AND SATURDAY. WHILE
WEAK IMPULSES EMBEDDED WITHIN THE BROAD SOUTHWESTERLY UPPER FLOW
PATTERN MAY TRIGGER A FEW SHOWERS AND THUNDERSTORMS FROM TIME TO
TIME...WIDESPREAD PRECIP IS NOT LIKELY. HAVE THEREFORE CONTINUED TO
KEEP POPS IN THE LOW CHANCE CATEGORY THROUGH SATURDAY. MAIN WEATHER
STORY BOTH DAYS WILL BE THE RETURN OF WARM AND HUMID CONDITIONS AS
HIGH TEMPERATURES REACH THE 80S AND DEWPOINTS CLIMB WELL INTO THE
60S.
WESTERN CONUS CLOSED LOW WILL LIFT INTO THE NORTHERN PLAINS ON
SUNDAY...THEN GRADUALLY OPEN AND SHIFT INTO THE NORTHERN GREAT LAKES
BY MONDAY. MODELS CONTINUE TO SPEED UP THIS PROCESS...WITH THE
ASSOCIATED COLD FRONT NOW EXPECTED TO PASS THROUGH CENTRAL ILLINOIS
LATE SUNDAY NIGHT. THE AIRMASS AHEAD OF THE FRONT WILL BECOME
MODERATELY UNSTABLE SUNDAY AFTERNOON/EVENING...WITH SBCAPES RANGING
FROM 1500 TO 2500J/KG. AT THE SAME TIME...0-6KM BULK SHEAR WILL
INCREASE INTO THE 35 TO 40KT RANGE AS UPPER TROUGH APPROACHES.
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THIS
FAVORABLE ENVIRONMENT WELL AHEAD OF THE COLD FRONT ALONG A
PRE-FRONTAL TROUGH...WITH SOME OF THE STORMS POTENTIALLY BECOMING
SEVERE DURING THE AFTERNOON AND EVENING. WILL CARRY LIKELY POPS
EVERYWHERE DURING THE DAY SUNDAY...THEN WILL BEGIN DECREASING POPS
FROM WEST TO EAST SUNDAY NIGHT. HAVE HUNG ON TO LOW CHANCE POPS
ALONG/SOUTH OF I-70 INTO MONDAY...BUT IF TRENDS CONTINUE THESE
MAY NEED TO BE REMOVED BY LATER SHIFTS.
ONCE FRONT PASSES...STRONG CANADIAN HIGH PRESSURE WILL BRING ANOTHER
CHILLY AIRMASS INTO CENTRAL ILLINOIS NEXT WEEK. MODELS DIFFER ON
EXACTLY HOW COOL IT WILL BE...WITH ECMWF NUMERIC GUIDANCE RUNNING
NEARLY 10 DEGREES COOLER THAN THE MEX. GIVEN STRENGTH OF
APPROACHING HIGH...HAVE UNDERCUT MEX BY A FEW DEGREES BUT HAVE NOT
YET GONE AS COOL AS THE ECMWF WOULD SUGGEST. RESULTING HIGHS WILL
SLIP INTO THE 60S FOR TUESDAY AND WEDNESDAY...WITH OVERNIGHT LOWS
DIPPING INTO THE 40S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 600 AM CDT THU MAY 14 2015
VFR CONDITIONS ARE EXPECTED THRU THE DAY WITH POSSIBLE MVFR CIGS
AFTER 04Z TONIGHT AS A WARM FRONT LIFTS TOWARDS THE AREA. A LARGE
AREA OF LIGHT RAIN WAS MAKING SLOW PROGRESS TO THE EAST AS IT
ENCOUNTERS SOME VERY DRY AIR AT THE LOW LEVELS OF THE ATMOSPHERE.
LATEST RAP FORECAST SOUNDINGS INDICATING CIGS WILL GRADUALLY
LOWER AS THE MOISTURE WORKS ITS WAY INTO OUR AREA TODAY BUT STILL
REMAIN VFR INTO EARLY THIS EVENING. AFTER THAT...PERSISTENT
MOISTURE ADVECTION FROM THE SOUTH WILL BRING ABOUT SOME MVFR CIGS
LATE THIS EVENING AND OVERNIGHT. THE BETTER CHANCES FOR -RA WILL
BE OVER PIA AND SPI TODAY BUT STILL WILL CARRY VCSH OVER AT BMI
AND DEC.
TONIGHT...AS THE BOUNDARY APPROACHES FROM THE SOUTH...WILL INCLUDE
VCTS IN THE FORECAST GROUPS AS WE SEE SOME ELEVATED INSTABILITY
DRAWN NORTHWARD. SURFACE WINDS WILL BE FROM THE SOUTHEAST AT 10 TO
15 KTS WITH OCCASIONAL GUSTS TO AROUND 20 KTS. LOOK FOR WINDS TO
VEER MORE INTO THE SOUTH TONIGHT WITH SPEEDS ONCE AGAIN IN THE 10
TO 15 KT RANGE. WILL NEED TO WATCH FOR THE POTENTIAL FOR NON-
CONVECTIVE LOW LEVEL WIND SHEAR OVERNIGHT AS SOUNDINGS INDICATE
40-50 KTS AT 1500-2500 FEET AFTER 03Z. FOR NOW...WITH THE THREAT
FOR SCATTERED TSRA IN THE AREA...WILL HOLD OFF MENTIONING IN THIS
SET OF FORECASTS.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS LINCOLN IL
603 AM CDT THU MAY 14 2015
.SHORT TERM...(TODAY)
ISSUED AT 319 AM CDT THU MAY 14 2015
1030MB HIGH CENTERED OVER THE EASTERN GREAT LAKES CONTINUES TO
CONTROL THE WEATHER ACROSS CENTRAL ILLINOIS EARLY THIS
MORNING...RESULTING IN COOL/DRY CONDITIONS WITH 07Z/2AM TEMPERATURES
MAINLY IN THE UPPER 40S AND LOWER 50S. AIRMASS IS QUITE DRY...AS
EVIDENCED BY THE 00Z KILX UPPER AIR SOUNDING AND CURRENT SURFACE
DEWPOINTS IN THE LOWER 40S. SHORT-WAVE TROUGH SHOWN ON LATEST WATER
VAPOR IMAGERY OVER KANSAS/OKLAHOMA WILL LIFT NORTHWARD
TODAY...SPREADING CLOUDS AND SHOWERS INTO PORTIONS OF CENTRAL
ILLINOIS. DUE TO THE VERY DRY AIR INITIALLY IN PLACE...THINK MODELS
ARE STILL TOO FAST IN BRINGING THE PRECIP INTO THE AREA. HAVE
THEREFORE SLOWED ITS NORTHEASTWARD SPREAD...WITH LOCATIONS
ALONG/EAST OF A BLOOMINGTON TO EFFINGHAM LINE REMAINING DRY UNTIL
EARLY AFTERNOON AT THE EARLIEST. AREAS ALONG THE INDIANA BORDER
WILL LIKELY STAY DRY FOR THE ENTIRE DAY. FURTHER WEST...RAIN
CHANCES INCREASE TO LIKELY ALONG/NORTHWEST OF THE ILLINOIS RIVER BY
AFTERNOON. DUE TO EXTENSIVE CLOUD COVER AND E/SE WINDS...HAVE GONE
SLIGHTLY BELOW MAV GUIDANCE FOR HIGHS TODAY...WITH READINGS
GENERALLY IN THE MIDDLE TO UPPER 60S...EXCEPT LOWER 70S ALONG/SOUTH
OF I-70 WHERE A FEW PEEKS OF SUNSHINE WILL BE POSSIBLE.
.LONG TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 319 AM CDT THU MAY 14 2015
UPPER WAVE WILL TRACK FROM MINNESOTA/IOWA THIS EVENING INTO THE
GREAT LAKES BY FRIDAY MORNING...KEEPING RAIN CHANCES ALIVE ACROSS
MUCH OF CENTRAL ILLINOIS. HIGHEST POPS WILL BE FOCUSED IN CLOSER
PROXIMITY TO THE STRONGEST FORCING FROM THE PEORIA AND
BLOOMINGTON AREAS NORTHWARD...TAPERING DOWN TO JUST SLIGHT CHANCES
ALONG/SOUTH OF I-70. FORECAST SOUNDINGS ARE INITIALLY QUITE
STABLE...HOWEVER MODEST ELEVATED INSTABILITY DEVELOPS OVERNIGHT
WITH MUCAPE VALUES APPROACHING 1000J/KG. WILL THEREFORE MENTION A
CHANCE OF THUNDER ACROSS THE BOARD TONIGHT.
ONCE THE WAVE EXITS...UPPER HEIGHTS RISE AND OVERALL FORCING FOR
ADDITIONAL CONVECTION WANES FOR BOTH FRIDAY AND SATURDAY. WHILE
WEAK IMPULSES EMBEDDED WITHIN THE BROAD SOUTHWESTERLY UPPER FLOW
PATTERN MAY TRIGGER A FEW SHOWERS AND THUNDERSTORMS FROM TIME TO
TIME...WIDESPREAD PRECIP IS NOT LIKELY. HAVE THEREFORE CONTINUED TO
KEEP POPS IN THE LOW CHANCE CATEGORY THROUGH SATURDAY. MAIN WEATHER
STORY BOTH DAYS WILL BE THE RETURN OF WARM AND HUMID CONDITIONS AS
HIGH TEMPERATURES REACH THE 80S AND DEWPOINTS CLIMB WELL INTO THE
60S.
WESTERN CONUS CLOSED LOW WILL LIFT INTO THE NORTHERN PLAINS ON
SUNDAY...THEN GRADUALLY OPEN AND SHIFT INTO THE NORTHERN GREAT LAKES
BY MONDAY. MODELS CONTINUE TO SPEED UP THIS PROCESS...WITH THE
ASSOCIATED COLD FRONT NOW EXPECTED TO PASS THROUGH CENTRAL ILLINOIS
LATE SUNDAY NIGHT. THE AIRMASS AHEAD OF THE FRONT WILL BECOME
MODERATELY UNSTABLE SUNDAY AFTERNOON/EVENING...WITH SBCAPES RANGING
FROM 1500 TO 2500J/KG. AT THE SAME TIME...0-6KM BULK SHEAR WILL
INCREASE INTO THE 35 TO 40KT RANGE AS UPPER TROUGH APPROACHES.
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THIS
FAVORABLE ENVIRONMENT WELL AHEAD OF THE COLD FRONT ALONG A
PRE-FRONTAL TROUGH...WITH SOME OF THE STORMS POTENTIALLY BECOMING
SEVERE DURING THE AFTERNOON AND EVENING. WILL CARRY LIKELY POPS
EVERYWHERE DURING THE DAY SUNDAY...THEN WILL BEGIN DECREASING POPS
FROM WEST TO EAST SUNDAY NIGHT. HAVE HUNG ON TO LOW CHANCE POPS
ALONG/SOUTH OF I-70 INTO MONDAY...BUT IF TRENDS CONTINUE THESE
MAY NEED TO BE REMOVED BY LATER SHIFTS.
ONCE FRONT PASSES...STRONG CANADIAN HIGH PRESSURE WILL BRING ANOTHER
CHILLY AIRMASS INTO CENTRAL ILLINOIS NEXT WEEK. MODELS DIFFER ON
EXACTLY HOW COOL IT WILL BE...WITH ECMWF NUMERIC GUIDANCE RUNNING
NEARLY 10 DEGREES COOLER THAN THE MEX. GIVEN STRENGTH OF
APPROACHING HIGH...HAVE UNDERCUT MEX BY A FEW DEGREES BUT HAVE NOT
YET GONE AS COOL AS THE ECMWF WOULD SUGGEST. RESULTING HIGHS WILL
SLIP INTO THE 60S FOR TUESDAY AND WEDNESDAY...WITH OVERNIGHT LOWS
DIPPING INTO THE 40S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 600 AM CDT THU MAY 14 2015
VFR CONDITIONS ARE EXPECTED THRU THE DAY WITH POSSIBLE MVFR CIGS
AFTR 04Z TONIGHT AS A WARM FRONT LIFTS TOWARDS THE AREA. A LARGE
AREA OF LIGHT RAIN WAS MAKING SLOW PROGRESS TO THE EAST AS IT
ENCOUNTERS SOME VERY DRY AIR AT THE LOW LEVELS OF THE ATMOSPHERE.
LATEST RAP FORECAST SOUNDINGS INDICATING CIGS WILL GRADUALLY
LOWER AS THE MOISTURE WORKS ITS WAY INTO OUR AREA TODAY BUT STILL
REMAIN VFR INTO EARLY THIS EVENING. AFTER THAT...PERSISTENT
MOISTURE ADVECTION FROM THE SOUTH WILL BRING ABOUT SOME MVFR CIGS
LATE THIS EVENING AND OVERNIGHT. THE BETTER CHANCES FOR -RA WILL
BE OVER PIA AND SPI TODAY BUT STILL WILL CARRY VCSH OVER AT BMI
AND DEC.
TONIGHT...AS THE BOUNDARY APPROACHES FROM THE SOUTH...WILL INCLUDE
VCTS IN THE FORECAST GROUPS AS WE SEE SOME ELEVATED INSTABILITY
DRAWN NORTHWARD. SURFACE WINDS WILL BE FROM THE SOUTHEAST AT 10 TO
15 KTS WITH OCCASIONAL GUSTS TO AROUND 20 KTS. LOOK FOR WINDS TO
VEER MORE INTO THE SOUTH TONIGHT WITH SPEEDS ONCE AGAIN IN THE 10
TO 15 KT RANGE. WILL NEED TO WATCH FOR THE POTENTIAL FOR NON-
CONVECTIVE LOW LEVEL WIND SHEAR OVERNIGHT AS SOUNDINGS INDICATE
40-50 KTS AT 1500-2500 FEET AFTR 03Z. FOR NOW...WITH THE THREAT
FOR SCATTERED TSRA IN THE AREA...WILL HOLD OFF MENTIONING IN THIS
SET OF FORECASTS.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...SMITH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1021 AM EDT THU MAY 14 2015
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 329 AM EDT THU MAY 14 2015
WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO
EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL...
STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF
A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /TODAY/...
ISSUED AT 1013 AM EDT THU MAY 14 2015
ONLY CHANGE TO THE ONGOING FORECAST WAS TO INCREASE CLOUD COVER
BASED ON CURRENT TRENDS AND GUIDANCE. THUS...DECIDED TO LOWER TEMPS A
DEGREE OR TWO ACROSS MOST OF THE FORECAST AREA. PREVIOUS DISCUSSION
FOLLOWS...
ISSUED AT 329 AM EDT THU MAY 14 2015
HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS
MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH
CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM
THE MID 40S TO THE MID 50S.
THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE
DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER
TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE
CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI
VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO
VALLEY AHEAD OF IT.
EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE
DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE
INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE
SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD
LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT
CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT
SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL
CONTINUE WITH A DRY FORECAST TODAY.
TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE
TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS
GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 329 AM EDT THU MAY 14 2015
FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE
PERIOD.
UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A
WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL
LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS
SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES
ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE
OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN
HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH
TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED
BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST
SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED.
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING
ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED
CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST
UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40
POPS OVER THE ENTIRE FORECAST AREA.
REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND
POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO
VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN
ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE
INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP
OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND
LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS
AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND
SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT.
TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB
TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S
MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE
WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE
NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY
PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS
SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK.
WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER
SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES
INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS
SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY
FORECAST AFTER MONDAY.
&&
.AVIATION /DISCUSSION FOR THE 141200Z TAFS/...
ISSUED AT 630 AM EDT THU MAY 14 2015
LAYERED CLOUDS ABOVE 050...UNRESTRICTED VISIBILITY EXPECTED AT THE
TERMINALS TODAY.
SURFACE WINDS 110-140 DEGREES AT 8-12 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...MRD/RYAN
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1020 AM EDT THU MAY 14 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 329 AM EDT THU MAY 14 2015
WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO
EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL...
STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF
A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /TODAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS
MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH
CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM THE
MID 40S TO THE MID 50S.
THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE
DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER
TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE
CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI
VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO
VALLEY AHEAD OF IT.
EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE
DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE
INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE
SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD
LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT
CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT
SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL
CONTINUE WITH A DRY FORECAST TODAY.
TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE
TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS
GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 329 AM EDT THU MAY 14 2015
FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE
PERIOD.
UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A
WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL
LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS
SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES
ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE
OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN
HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH
TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED
BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST
SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED.
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING
ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED
CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST
UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40
POPS OVER THE ENTIRE FORECAST AREA.
REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND
POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO
VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN
ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE
INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP
OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND
LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS
AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND
SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT.
TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB
TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S
MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE
WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE
NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY
PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS
SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK.
WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER
SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES
INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS
SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY
FORECAST AFTER MONDAY.
&&
.AVIATION /DISCUSSION FOR THE 141500Z IND TAF UPDATE/...
ISSUED AT 1020 AM EDT THU MAY 14 2015
NOTHING TO NOTE REGARDING UPDATE.
PREVIOUS DISCUSSION FOLLOWS...
ISSUED AT 630 AM EDT THU MAY 14 2015
LAYERED CLOUDS ABOVE 050...UNRESTRICTED VISIBILITY EXPECTED AT THE
TERMINALS TODAY.
SURFACE WINDS 110-140 DEGREES AT 8-12 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...JAS/MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
630 AM EDT THU MAY 14 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 329 AM EDT THU MAY 14 2015
WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO
EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL...
STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF
A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /TODAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS
MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH
CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM THE
MID 40S TO THE MID 50S.
THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE
DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER
TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE
CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI
VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO
VALLEY AHEAD OF IT.
EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE
DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE
INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE
SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD
LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT
CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT
SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL
CONTINUE WITH A DRY FORECAST TODAY.
TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE
TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS
GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 329 AM EDT THU MAY 14 2015
FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE
PERIOD.
UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A
WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL
LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS
SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES
ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE
OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN
HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH
TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED
BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST
SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED.
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING
ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED
CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST
UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40
POPS OVER THE ENTIRE FORECAST AREA.
REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND
POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO
VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN
ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE
INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP
OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND
LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS
AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND
SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT.
TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB
TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S
MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE
WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE
NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY
PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS
SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK.
WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER
SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES
INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS
SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY
FORECAST AFTER MONDAY.
&&
.AVIATION /DISCUSSION FOR THE 141200Z TAFS/...
ISSUED AT 630 AM EDT THU MAY 14 2015
LAYERED CLOUDS ABOVE 050...UNRESTRICTED VISIBILITY EXPECTED AT THE
TERMINALS TODAY.
SURFACE WINDS 110-140 DEGREES AT 8-12 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...JAS
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSINDIANAPOLIS
WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
626 AM CDT THU MAY 14 2015
.SYNOPSIS...
ISSUED AT 312 AM CDT THU MAY 14 2015
AS OF 2 AM...THE DRY AIRMASS OVER FAR EASTERN
MO...EASTERN IOWA AND ILLINOIS HAS HELD ITS GROUND AS THE LARGE
PLUME OF MOISTURE ADVECTION HEADS MAINLY NORTHWARD OVER THE WESTERN
2/3RDS OF IOWA AND THE MISSOURI RIVER VALLEY. THUS...WE HAVE
SITUATION WHERE LOCATIONS ARE SEEING VERY SLOW PROGRESS EAST OF THE
WIDESPREAD RAIN. WITH LOW LEVEL THROUGH 850MB WINDS REMAINING FROM
THE EAST TO SOUTHEAST THROUGH EARLY MORNING...THIS SLOW PROGRESSION
SHOULD CONTINUE TO BE SEEN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 312 AM CDT THU MAY 14 2015
TODAY AND TONIGHT... MODEL GUIDANCE ALL BRINGS THE
MOISTURE ADVECTION INTO THE HEART OF THE CWA DURING THE DAY
TODAY...WITH THE TIMING THE MAIN DIFFERENCES. THE ECMWF AND GFS ARE
BOTH QUICKER IN VEERING WINDS AT 850MB AROUND COMPARED TO THE SLOWER
NAM. MESOSCALE MODELS ARE A BIT SPLIT...WITH THE HRRR AND RAP
AGGRESSIVE IN VEERING MOISTURE INTO THE AREA...WHILE THE ARW AND NMM
ARE SLOWER...AND MUCH CLOSER TO THE NAM DEPICTION. THIS DIFFERENCE
IS MAKING A CHALLENGING CALL..SINCE ALL ARE INITIALIZING RATHER
WELL WITH MEASURABLE RAINS IN IOWA MAINLY WEST OF I-35 THROUGH 06Z.
HOWEVER...LOOKING AT OUR RADAR...THERE ARE ALREADY SHOWERS AT LEAST
ALOFT...IF NOT HITTING THE GROUND AS FAR EAST AS A VINTON TO KEOKUK
LINE. THAT SUPPORTS MOISTURE TRANSPORT BEING WELL EAST OF THE MORE
CONSERVATIVE SOLUTIONS...AND WILL PLAY A POP FORECAST MORE CLOSELY
TO THE ECMWF TODAY. EXPECT CLOUDY SKIES THROUGHOUT...WITH LITTLE
HEATING WEST ALL DAY...WHILE EAST HAS A DRY MORNING...AND MODEST
TEMPERATURE RECOVERY TO THE MID 60S. WILL SPREAD CATEGORICAL POPS
EAST TO AROUND MANCHESTER TO BURLINGTON BY MID MORNING...THEN SHIFT
LIKELY POPS EAST OVER THE REST OF THE CWA THIS AFTERNOON. THIS MAY
NEED A CATEGORICAL SHIFT UPWARDS AS WELL...BUT WILL GIVE A 10
PERCENT NOD TO THE SLOWER SOLUTIONS HERE...AND KEEP IT LIKELY.
TONIGHT...THE GLOBAL MODELS STRONGLY SUGGEST AN UPTICK IN CONVECTIVE
POTENTIAL OVER THE NORTHERN 2/3RDS OF THE CWA THIS EVENING. IN
FACT...THEY SUGGEST A WEAK MCS OF SORTS...BUT THE NAM AND OTHER
MESOMODELS SUGGEST THIS ACTIVITY FARTHER SOUTH. I AM DOUBTFUL OF
BUILDING ANY SURFACE BASED CAPE ANYWHERE IN ILLINOIS TODAY...SO THE
NORTHERN SOLUTIONS ARE MORE LIKELY SINCE THE VORTICITY CENTER
PASSING OVER THAT REGION SHOULD SUPPORT AN EVENING ROUND OF LIFT.
MUCAPE SHOULD BE LIMITED TO THE SOUTH HALF AND ONLY BE 500 TO 700
PER THE GFS SOLUTIONS...THUS WILL KEEP THUNDER LIMITED TO THAT
PORTION OF THE AREA TONIGHT. BY 06Z...ALL MODELS SHOW THE LLJ
VEERING EAST...WITH THE VORT PASSING INTO WISCONSIN BY THEN...THUS
COVERAGE SHOULD BECOME FAR MORE ISOLATED AFTER THAT TIME. LOWS
TONIGHT...WITH MUCH HIGHER DEWPOINTS IN PLACE THAN THIS
MORNING...WILL MAINLY BE IN THE MID 50S NORTH TO AROUND 60 SOUTH.
ERVIN
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 312 AM CDT THU MAY 14 2015
FRIDAY...UPPER-LEVEL WINDS WILL BE VERY LIGHT AS RIDGING BUILDS IN
BEHIND A SHORTWAVE OVER THE UPPER GREAT LAKES AND AHEAD OF A
LONGWAVE TROUGH AND CLOSED UPPER LOW OVER THE WESTERN U.S.
THE MOST NOTICEABLE SENSIBLE WEATHER ON FRIDAY WILL BE AN
INCREASINGLY HUMID AIRMASS AS SFC DEWPOINTS RISE INTO THE 60S
THANKS TO S/SW WINDS. THE MOIST ATMOSPHERE COUPLED WITH HIGHS IN
THE MID 70S TO LOWER 80S WILL YIELD MUCH GREATER INSTABILITY
COMPARED TO THE PAST SEVERAL DAYS. MUCAPE VALUES OF 1500-2500
J/KG ARE LIKELY. THEREFORE ANY STORM THAT FORMS COULD BE BRIEFLY
STRONG OR SEVERE...ALTHOUGH LACK OF SUFFICIENT VERTICAL SPEED
SHEAR WOULD INHIBIT ANYTHING PROLONGED OR WIDESPREAD.
CONVECTIVE COVERAGE...IT LOOKS ISOLATED TO SCATTERED AT BEST.
THERE DOES NOT LOOK TO BE MUCH IN THE WAY OF FORCING FOR ASCENT
DURING THE DAY AND FORECAST SOUNDINGS DO HAVE A LITTLE SBCIN.
HOWEVER...THE MODELS ARE SHOWING AN UPTICK IN COVERAGE FRIDAY
NIGHT WHEN A SUBTLE 500MB VORTICITY EMBEDDED IN THE SW MID-LEVEL
FLOW MAY TRAVERSE E IOWA/W ILLINOIS. ADDITIONALLY...SOME WEAK
850MB CONVERGENCE IS FORECAST ON THE NOSE OF A SLIGHTLY STRONGER
WIND FIELD OVER SOUTH-CENTRAL IOWA INTO NW MISSOURI.
SATURDAY...HUMID WEATHER CONTINUES ALONG WITH A SCATTERED
THUNDERSTORM THREAT. NEGLIGIBLE FORCING FOR ASCENT...BUT DAYTIME
HEATING MAY BE ENOUGH TO SET OFF SCATTERED SHOWERS AND
STORMS...ESPECIALLY DURING THE AFTN/EVENING. CONDITIONAL
INSTABILITY IS FORECAST TO BE NEAR OR SLIGHTLY HIGHER THAN ON
FRIDAY. 0-6 KM BULK SHEAR MAY PEAK NEAR 30 KTS SO A LITTLE HIGHER
THAN FRIDAY AS WELL.
SPC HAS OUTLOOKED THE EXTREME WESTERN PORTION OF THE DVN
CWA IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS. STORMS THAT FORM
IN THIS ENVIRONMENT HAVE THE POTENTIAL TO PRODUCE HAIL AND WIND
GUSTS AT SEVERE LEVELS BUT IF ANYTHING DOES OCCUR IT WILL BE
ISOLATED.
FOR FRIDAY AND SATURDAY ANY STORMS THAT FORM WILL MOVE
SLOWLY...GENERALLY FROM SW TO NE AT LESS THAN 30 MPH...AND POSE A
THREAT FOR LOCALIZED HEAVY RAINFALL VIA FORECAST STORM MOTION
VECTORS AND PWAT VALUES NEAR 1.50 INCHES.
SUNDAY...THERE IS A RISK FOR STRONG AND SEVERE STORMS ACROSS THE
FORECAST AREA. MODEL GUIDANCE IS SHOWING OVERLAP OF HIGHER
INSTABILITY AND SHEAR IN ADVANCE OF AN APPROACHING COLD FRONT. RIGHT
NOW BEST SYNOPTIC DYNAMICS PASS OVER WESTERN IOWA INTO MINNESOTA AS
DOES THE SFC LOW...SO STORM COVERAGE ACROSS THE DVN CWA MAY NOT BE
THAT WIDESPREAD AND MAY BE MOSTLY ANCHORED TO THE VICINITY OF THE
SFC COLD FRONT.
MONDAY THROUGH WEDNESDAY...BOTH THE GFS AND ECMWF ADVECT A MUCH
DRIER AIRMASS INTO THE UPPER MIDWEST AS A SPRAWLING HIGH PRESSURE
SYSTEM DROPS OUT OF CANADA INTO THE NORTHERN U.S. THREAT FOR
MEASURABLE RAIN IS QUITE LOW AT THIS POINT SO SHOULD BE A PLEASANT
PERIOD WITH HIGHS IN THE 60S AND LOWS IN THE 40S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 615 AM CDT THU MAY 14 2015
A SLOW MOVING BAND OF RAIN WILL MOVE EAST AFFECTING EASTERN IOWA
TERMINALS THROUGH LATE MORNING. CLOUD BASES WILL BE QUITE
HIGH...WITH CIGS AROUND 12000 FT...LOWERING BY AFTERNOON TO
AROUND 5000 FT. A WARM FRONT WILL BRING MORE MOIST AIR TO THE
REGION BY TONIGHT...RESULTING IN CIGS LOWERING TO AROUND 2000 TO
3000 FT...AND VISIBILITIES TO 3 TO 5 MILES IN LIGHT FOG...AND SOME
SHOWERS. CONDITIONS ARE LIKELY TO REMAIN SOMEWHAT VARIABLE AFTER
00Z...WITH PASSING SHOWERS AND EVEN A THUNDERSTORM POSSIBLE.
ERVIN
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...UTTECH
AVIATION...ERVIN
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
930 AM MDT THU MAY 14 2015
.UPDATE...
MADE A FEW CHANGES TO THE FORECAST THROUGH THIS EVENING. STRATUS
HAD OVERSPREAD THE AREA WITH THE EXCEPTION OF THE MOUNTAINS AND
NEARBY FOOTHILLS. MID CLOUDS WERE MOVING N OVER THE WESTERN ZONES
IN THE MOIST FLOW AHEAD OF THE UPPER LOW ALONG THE W COAST. IN
GENERAL...HAVE INCREASED CLOUD COVER OVER MOST OF THE AREA THROUGH
THE DAY. RAP SOUNDINGS DID SHOW CLOUDS IN THE E DISSIPATING THIS
AFTERNOON SO REFLECTED THIS IN THE GRIDS. ALSO WEBCAMS/SURFACE
OBSERVATIONS INDICATED PATCHY FOG OVER MOST OF THE AREA...SO HAVE
SPREAD THE FOG MENTION FURTHER W THROUGH 18Z. DUE TO THE CLOUD
COVER...HAVE LOWERED TEMPERATURES A COUPLE OF DEGREES TOWARD THE
NEW WRF. THE CLOUDS WILL INHIBIT THUNDERSTORM FORMATION...SO HAVE
CONFINED THUNDER TO THE SUNNIER AREAS...IE...THE MOUNTAINS AND
FOOTHILLS THIS AFTERNOON AND EVENING. SREF SHOWED GOOD
PROBABILITIES OF 500 J/KG OF SURFACE CAPE IN THESE AREAS...WITH
CAPES DIMINISHING QUICKLY THIS EVENING. RAP SHOWED MARGINAL SHEAR
OVER THE AREA.
NEW WRF SHOWED DRY SLOT MOVING N QUICKLY LATE TONIGHT WHICH WOULD
CONTRADICT THE HIGH POPS AFTER 06Z. WILL WAIT TIL MORE GUIDANCE
COMES IN BEFORE MAKING ANY CHANGES LATE TONIGHT. ARTHUR
&&
.SHORT TERM...VALID FOR TDY AND FRI...
MINIMAL CHANGES TO THE SHORT TERM FORECAST PERIOD...AS UNSETTLED
PATTERN PERSISTS. MODELS HAVE BEEN CONSISTENT WITH THIS
PATTERN FOR SEVERAL DAYS...SO FORECAST IS IN GOOD SHAPE OVERALL.
DIFFLUENT FLOW ALOFT AHEAD OF APPROACHING UPPER LEVEL PACIFIC LOW
PRESSURE SYSTEM...AND PERSISTENT UPSLOPE SFC FLOW PREVAIL ACROSS
THE REGION FOR TODAY AND FRIDAY. INCREASING MOISTURE AVAILABILITY
AND SHORTWAVE ACTIVITY ARE ALSO EXPECTED THROUGH THE
PERIOD...RESULTING IN INCREASING CHANCES FOR PRECIPITATION.
ADDITIONALLY...IMPROVED CAPES AND SHEAR PROFILE THROUGH THE
TODAY...WILL LEND SUPPORT FOR INCREASED CHANCES OF THUNDER TODAY
AND INTO TONIGHT. BEST CHANCES TODAY WILL BE FROM SHERIDAN TO
BILLINGS AND WEST THROUGH THIS AFTERNOON...AND SPREADING EASTWARD
THROUGH THIS EVENING AND TONIGHT. SHOWERS WILL BE MORE WIDESPREAD
ON FRIDAY. SHEAR AND CAPE DO NOT APPEAR QUITE AS GOOD FOR
FRIDAY...AND WILL ALSO HAVE LIMITED POTENTIAL FOR ADDITIONAL
ENERGY FROM DIURNAL HEATING WITH CLOUD COVER. SO THUNDER POTENTIAL
APPEARS A BIT LOWER FOR FRIDAY...BUT HAVE STILL KEPT A MENTION OF
THUNDER AT THIS TIME.
TEMPS WILL STILL HAVE A CHANCE TO WARM UP...BUT COOLING TREND
WILL BEGIN TODAY. HIGHS IN THE UPPER 50S TO UPPER 60S ARE
EXPECTED. CLOUD COVER ACROSS THE REGION...AND PERSIST SHOWER
ACTIVITY ON FRIDAY WILL LIMIT TEMPS TO MAINLY THE 50S. SOME AREAS
ALONG THE SOUTHERN BORDER MAY CREEP INTO THE 60S...BUT WILL
GREATLY DEPEND ON HOW FAR NORTH DRY SLOTTING OCCURS. AAG
.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...
WET WEATHER COMING THIS WEEKEND THOUGH THERE ARE STILL SOME
DETAILS TO BE WORKED OUT.
ENERGY EMERGING FROM DEEP WESTERN CONUS LOW WILL LIFT OUT OF WY
FRIDAY NIGHT AND CLOSE OFF SOMEWHERE OVER SOUTHEAST MT ON
SATURDAY. GOOD GENERAL CONSENSUS AMONG THE MODELS HERE BUT THE
EXACT LOCATION OF THE MID LEVEL LOW WILL BE CRUCIAL. WILL CONTINUE
TO FOLLOW A MODEL BLEND IN THIS REGARD. BEST CHANCE OF RAIN
SATURDAY WILL BE FROM BILLINGS WEST AND NORTHWARD...WITH DRY
SLOTTING A REAL POSSIBILITY IN FAR SOUTHEAST MT AND SHERIDAN
COUNTY. BILLINGS MAY NOT FAR FROM THE EDGE BUT ALL MODELS TAKE MID
LEVEL LOW TO OUR EAST WHICH WOULD SUGGEST PLENTY OF RAIN FOR THE
METRO AREA ON SATURDAY. IF THE LOW WERE TO TRACK JUST SLIGHTLY
WEST WE COULD SEE A BREAK IN THE PCPN. OVER TIME AS THE LOW SHIFTS
EAST WE WILL SEE TROWAL WRAP BACK THROUGH OUR AREA AS THE FLOW
TURNS NORTHERLY. THIS WILL RESULT IN WIDESPREAD PCPN SATURDAY
NIGHT INTO SUNDAY. LOW WILL DEPART SUNDAY AFTERNOON AND NIGHT WITH
DRIER AIR ADVECTING IN FROM THE NORTH. AS FOR PCPN AMOUNTS...GFS
SEEMS TO BE SUFFERING SOME CONVECTIVE FEEDBACK ISSUES BUT A MODEL
BLEND WILL STILL PRODUCE A WIDESPREAD 1-2 INCHES WITH LOCALLY
HIGHER AMTS...IE MAYBE 3 INCHES...AIDED BY CONVECTIVE ENHANCEMENT
PRIOR TO THE SATURDAY TROWAL. SHOULD ALSO BE NOTED THAT GULF
MOISTURE WILL BE INVOLVED SO MOISTURE AVAILABILITY WILL NOT BE AN
ISSUE THROUGH THE COURSE OF THIS EVENT.
MOUNTAINS COULD SEE SIGNIFICANT SNOWFALL ESPECIALLY BEGINNING
SATURDAY NIGHT AS WE COLD ADVECT AND 700MB TEMPS FALL TO NEAR -5C.
WILL ALSO NEED TO KEEP AN EYE ON CLIPPER WHICH WILL EMERGE FROM
THE CANADIAN ARCTIC AND PUSH THROUGH SASKATCHEWAN BY SATURDAY
NIGHT. THIS WILL BE ASSOCIATED WITH A LOW LEVEL COLD SURGE WHICH
COULD DROP 850MB TEMPS TO NEAR 0C BY SUNDAY. IT IS NOT OUT OF THE
QUESTION THAT SOME OF THE HIGHER HILLS OF SOUTHEAST MT COULD SEE
A MIX WITH WET SNOW ON SUNDAY PRIOR TO THE DRYING.
SHORTWAVE RIDGE WILL BUILD IN SUNDAY NIGHT AND MONDAY FOR A BRIEF
PERIOD OF QUIETER WEATHER. NEXT PACIFIC TROF WILL MOVE INTO THE
WESTERN CONUS AND SET THE STAGE FOR ANOTHER PERIOD OF UPPER
DIFFLUENT FLOW...GULF MOISTURE ADVECTION AND A GOOD CHANCE OF
SHOWERS IN OUR REGION FROM MONDAY NIGHT THROUGH WEDNESDAY. ANOTHER
WIDESPREAD PCPN EVENT IS A POSSIBILITY AS SUGGESTED BY THE MOST
RECENT GFS.
TEMPERATURES WILL BE WELL BELOW NORMAL THIS WEEKEND WITH MOST
AREAS SEEING HIGHS ONLY IN THE 50S. SHOULD SEE SOME MODEST
MODERATION NEXT MONDAY/TUESDAY BUT WITH A PERSISTENT EAST WIND
REGIME KEEPING OUR TEMPS IN CHECK. TEMPS SHOULD STAY BELOW NORMAL
THROUGH THE MIDDLE OF NEXT WEEK.
JKL
&&
.AVIATION...
AREA OF STRATUS WITH MVFR TO LOCAL IFR CEILINGS WILL IMPACT OUR
ENTIRE AREA THIS MORNING...THE EXCEPTION BEING KLVM...KSHR AND THE
FOOTHILLS LOCATIONS WHERE VFR CONDITIONS WILL PREVAIL. CONDITIONS
ARE EXPECTED TO IMPROVE TO VFR BY 18Z. SCATTERED SHOWERS AND
THUNDERSTORMS WILL DEVELOP ALONG AND WEST OF A KSHR- KBIL LINE
THIS AFTERNOON AND EVENING. MVFR CONDITIONS WILL BE POSSIBLE IN
ANY SHOWER/THUNDERSTORM ACTIVITY. THE MOUNTAINS WILL BE OBSCURED
AT TIMES. HOOLEY
&&
.PRELIMINARY POINT TEMP/POPS...
TDY FRI SAT SUN MON TUE WED
-------------------------------------------------------
BIL 064 048/056 045/053 041/052 038/060 041/056 042/055
2/W 66/T 78/W 76/W 22/W 24/W 55/W
LVM 058 044/056 040/053 038/054 035/058 037/055 038/057
4/T 56/T 78/W 75/W 23/T 35/W 54/W
HDN 068 047/060 045/055 041/052 035/063 041/059 041/057
1/E 56/T 67/W 76/W 22/W 24/W 55/W
MLS 065 046/058 046/058 041/052 035/058 040/058 041/058
1/B 36/T 87/T 77/W 21/B 23/W 44/W
4BQ 066 047/058 046/062 042/049 032/059 039/055 039/055
1/B 46/T 75/T 77/W 21/B 34/W 55/W
BHK 061 042/058 045/063 041/049 031/055 036/055 038/055
1/B 16/T 85/T 66/W 21/B 23/W 44/W
SHR 064 044/061 041/056 038/050 034/058 040/055 038/055
2/T 66/T 56/W 77/W 22/T 35/W 55/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
621 AM CDT THU MAY 14 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CDT THU MAY 14 2015
TODAY AND TONIGHT...TIMING TOOLS AND THE HRRR MODEL SHOW THE RAIN
SHIELD ROTATING NORTHEAST AT 15 MPH THIS MORNING SUGGESTING AN EXIT
TIME AROUND 15Z. SATELLITE SHOWS TRAPPED BOUNDARY LAYER MOISTURE
PRODUCING LOW STRATUS WHICH WILL SLOWLY ERODE THIS MORNING AS WEST
AND NORTHWEST WINDS INCREASE TO 10 MPH AFTER SUNRISE. THE
TEMPERATURE FORECAST FOLLOWS THE UPPER EDGE OF THE MODEL ENVELOP FOR
HIGHS IN THE 70S TO 80 SOUTH.
WEAK HIGH PRESSURE WILL BUILD INTO THE FCST AREA THIS AFTERNOON WITH
A FRONT SETTING UP ACROSS SRN NEB BY LATE THIS AFTN. THE NAM
SUGGESTS A LEAD DISTURBANCE OVER AZ THIS MORNING WILL MOVE THROUGH
THE ROCKIES TODAY AND LIFT THE FRONT NORTH TO NEAR THE NORTH PLATTE
VALLEY TONIGHT. MODEST WARM AIR ADVECTION FROM 850MB ON UP HELPS TO
LIFT THE FRONT NORTH BUT ALSO DESTABILIZES THE ATMOSPHERE PRODUCING
SCATTERED TSTMS FROM 06Z ONWARD.
INSTABILITY PROFILES IN THE NAM INDICATE AROUND 1500 J/KG OF CAPE
COMPUTED AT 800 MB AND 3000 J/KG AT 850 MB. THE DRIER GFS SHOWS VERY
LITTLE INSTABILITY AT THESE LEVELS. THE SREF SUPPORTS THE NAM SOLN
DRIVING PWAT TO AN INCH OVERNIGHT. LAPSE RATES ARE STEEP IN BOTH THE
GFS AND NAM BUT THE BULK SHEAR IS WEAK WITH LINEAR WIND FIELDS. THIS
WOULD SUGGEST THE POTENTIAL FOR PULSE TSTM BEHAVIOR WITH
HAIL...POSSIBLY BRIEFLY LARGE. POPS ARE SET AT 40 PERCENT TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 326 AM CDT THU MAY 14 2015
LITTLE HAS CHANGED OVER THE LAST 24 HOURS IN THE LONG RANGE.
DETERMINISTIC MODELS AND ENSEMBLE MEANS REMAIN IN SOUND AGREEMENT
WITH THE EVOLUTION OF THE UPPER LEVEL SYNOPTIC PATTERN THROUGH THE
MIDDLE OF NEXT WEEK. FORECASTER CONFIDENCE IS HIGH FOR THE PROLONGED
CONTINUATION OF AN ACTIVE PATTERN OVER THE CENTRAL PLAINS WITH
PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS.
LEAD SHORTWAVE EJECTS NORTHEAST INTO THE CENTRAL PLAINS FRIDAY
SETTING THE STAGE FOR POTENTIAL SEVERE WEATHER IN THE SANDHILLS
REGION. A 60KT UPPER LEVEL JET NOSES INTO THE CWA AS A LEE SIDE AREA
OF LOW PRESSURE DEEPENS OVER NORTHEAST COLORADO...WITH A SHARPENING
DRYLINE FROM SW NEBRASKA INTO WESTERN KS. A POLEWARD ADVANCING WARM
FRONT WILL ALSO STRETCH EAST ACROSS THE CWA...HOWEVER THE EXACT
PLACEMENT STILL REMAINS IN QUESTION. THUNDERSTORM INITIATION IS
EXPECTED BY MID TO LATE AFTERNOON IN A ZONE OF POOLING RICH THETA-E
AIR AND INCREASING INSTABILITY BETWEEN THE NORTHEAST SURGING DRYLINE
AND THE WARM FRONT. STRONG DEEP LAYER SHEAR IN EXCESS OF 40 KTS AND
STEEPENING MID-LEVEL LAPSE RATES WILL FOSTER AN ENVIRONMENT
FAVORABLE FOR THE DEVELOPMENT OF SUPERCELL THUNDERSTORMS CAPABLE OF
PRODUCING LARGE HAIL AND DAMAGING WINDS. TORNADO THREAT INCREASES
LATE IN THE DAY IN CONCERT WITH A STRENGTHENING LOW LEVEL
JET...WHICH WILL CREATE MORE FAVORABLE LOW LEVEL SHEAR PROFILES AND
ELONGATED HODOGRAPHS IN THE VICINITY OF THE WARM FRONT AND WESTWARD
TOWARD THE TRIPLE POINT IN THE EASTERN NEBRASKA PANHANDLE. SEVERAL
UNCERTAINTIES STILL REMAIN WITH THE SEVERE WEATHER SETUP FOR
FRIDAY...PRIMARILY DUE TO MODEL DIFFERENCES WITH THE POSITION OF THE
AFOREMENTIONED WARM FRONT. SCATTERED CONVECTION WILL BE ONGOING
FRIDAY MORNING IN A ZONE ISENTROPIC ASCENT ALONG AND NORTH OF THE
WARM FRONT AS IT MOVES NORTHWARD OUT OF KANSAS. MODELS ARE
STRUGGLING WITH THEIR PROGRESSION OF THE FRONT DUE TO DIFFERENCES IN
THEIR CONVECTIVE OUTPUT. ALSO OF CONCERN IS THE LACK OF CONVECTIVE
INHIBITION INDICATED IN MODEL FORECAST SOUNDINGS. A WEAK CAP FAVORS
AN EARLIER ONSET TO CONVECTION AND LIMITS THE DEGREE OF
DESTABILIZATION IN THE WARM SECTOR PRIOR TO STORM INITIATION.
THUNDERSTORM ACTIVITY PUSHES NORTHEAST ALONG THE NOSE OF A VEERING
LLJ FRIDAY NIGHT. A LARGE UPPER LEVEL LOW OVER THE DESERT SOUTHWEST
KICKS NORTHEAST INTO THE CENTRAL PLAINS SATURDAY AND THE ATMOSPHERE
OVER THE CWA RELOADS WITH ANOTHER ROUND OF SEVERE WEATHER POSSIBLE.
MODEL CONSENSUS HAS TRENDED A BIT FURTHER WEST WITH THE WEDNESDAY
EVENING RUNS. THE LEE SIDE AREA OF LOW PRESSURE FROM FRIDAY
RETROGRADES BACK WESTWARD...WITH A SFC TROUGH AXIS STRETCHING FROM
THE KS/CO BORDER NORTHWARD INTO WESTERN NEBRASKA. THUNDERSTORM
INITIATION IS LIKELY ONCE AGAIN DURING THE AFTERNOON HOURS ALONG AND
AHEAD OF THE SFC TROUGH AS STRONG UPPER LEVEL LIFT OVERSPREADS THE
INCREASINGLY UNSTABLE WARM SECTOR. WIND PROFILES LOOK FAIRLY
UNIDIRECTIONAL THROUGH A DEEP LAYER SATURDAY...SO THUNDERSTORMS WILL
LIKELY EXPERIENCE UPSCALE GROWTH WITH LARGE HAIL...DAMAGING
WINDS...AND LOCALLY HEAVY RAINFALL THE PRIMARY THREATS AS THEY TRACK
NORTH AND EAST THROUGH THE EVENING.
A TRANSITORY RIDGE MOVES OVER THE CENTRAL PLAINS EARLY IN THE WEEK
BRINGING A TEMPORARY PERIOD OF DRIER CONDITIONS. PRECIPITATION
CHANCES RAMP UP AGAIN BY TUESDAY AS ANOTHER UPPER LEVEL LOW MOVES
ONSHORE FROM THE PACIFIC AND INTO THE WESTERN CONUS. RAINFALL
CHANCES INCREASE AS A PLUME OF SUBTROPICAL MOISTURE ALOFT SURGES
NORTHEAST OUT OF THE BAJA REGION...WHILE NORTHWARD MOISTURE
TRANSPORT IN THE LOWER LEVELS LIFTS UP AND OVER THE WARM FRONT
SITUATED JUST SOUTH OF THE CWA. CROSS SECTION ANALYSIS OF THE GFS
AND EC SHOW STRONG AND PERSISTENT ISENTROPIC LIFT A OVER THE
CWA...ESPECIALLY TUESDAY NIGHT. EVEN THOUGH IT IS IN THE DAY 6-7
RANGE...STUCK WITH LIKELY POPS GIVEN THE HIGHLY FAVORABLE SETUP FOR
WIDESPREAD QPF AND STRONG MODEL CONSENSUS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 620 AM CDT THU MAY 14 2015
IMPROVEMENT TO VFR IS EXPECTED 15Z-18Z THIS MORNING...LARGELY THE
RESULT OF MIXING PROCESSES. OTHERWISE...SATELLITE TIMING TOOLS
SUGGEST MVFR WOULD LAST ALL DAY EAST OF HIGHWAY 61.
TONIGHT...AN UPPER LEVEL DISTURBANCE ACROSS AZ SHOULD MOVE THROUGH
THE FCST AREA. THE MODELS SUGGEST SCATTERED TSTMS WILL DEVELOP AS
THE DISTURBANCE MOVES THROUGH THE FCST AREA.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MARTIN
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
607 AM CDT THU MAY 14 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT THU MAY 14 2015
ALTHOUGH THESE FIRST 24 HOURS CERTAINLY DO NOT FEATURE THE
POTENTIALLY "HIGHER IMPACT" THREAT OF SEVERE THUNDERSTORMS FOR
FRIDAY-SATURDAY AS DESCRIBED IN THE LONG TERM SECTION
BELOW...TODAY AND TONIGHT COME WITH THEIR OWN SET OF
CHALLENGES...NAMELY: 1) TIMING THE END OF RAIN/DRIZZLE THIS
MORNING...2) TIMING HOW QUICKLY/SLOWLY WIDESPREAD CLOUDS DEPART
FROM WEST-EAST TODAY AND RESULTANT IMPACT ON HIGH TEMPS...AND 3)
TRYING TO DETERMINE HOW MUCH THUNDERSTORM DEVELOPMENT/COVERAGE
OCCURS LATE TONIGHT AND WHETHER A FEW OF THESE STORMS COULD
ACTUALLY BE STRONG TO MARGINALLY SEVERE (DESPITE THE LACK OF AN
OFFICIAL SPC MARGINAL RISK AREA ON THE LATEST DAY 1 OUTLOOK).
STARTING OFF WITH THE PRESENT SCENE AS OF 08Z/3AM THIS
MORNING...WE ARE IN THE LATTER STAGES OF A REMARKABLY
BENEFICIAL...LARGELY STRATIFORM (NON-CONVECTIVE/THUNDERSTORM)
WIDESPREAD RAIN EVENT THAT HAS BEEN GOING ON SINCE LATE WED
AFTERNOON/EARLY EVENING. AS OF THIS WRITING...RAIN IS STARTING TO
STEADILY WIND DOWN/BECOME MORE SPOTTY WITHIN THE WESTERN HALF OF
THE CWA...WHILE CONTINUING STEADY IN EASTERN COUNTIES. PER SEVERAL
AUTOMATED AIRPORT GAUGES AND RADAR ESTIMATION...IT APPEARS LIKELY
THAT THE MAJORITY OF THE CWA IS GOING TO END UP WITH A SOLID
0.50-1.00" BEFORE RAIN COMPLETELY ENDS THIS MORNING...CERTAINLY A
WELCOMED EVENT FOR THE MOST PART. THIS LARGE SHIELD OF MAINLY
LIGHT RAIN IS BEING DRIVEN IN THE MID-UPPER LEVELS BY A SLIGHTLY
NEGATIVELY TILTED SHORTWAVE TROUGH CURRENTLY PASSING DIRECTLY
THROUGH THE HEART OF THE CENTRAL PLAINS. WHILE A SMALL ZONE OF
SHORTWAVE RIDGING IS MOVING IN BEHIND THIS WAVE...THE CENTER OF
THE NEXT SIGNIFICANT UPPER LEVEL SYSTEM IS SLOWLY BUT SURELY
APPROACHING THE PACIFIC COAST. AT THE SURFACE EARLY THIS
MORNING...WEAK LOW PRESSURE CENTERED TO THE WEST IS PROMOTING
FAIRLY UNIFORM SOUTHEAST BREEZES GENERALLY 7-13 MPH IN MOST AREAS.
LOW TEMPS APPEAR ON TRACK TO BOTTOM OUT IN THE 51-54 RANGE IN
MOST PLACES.
NOW LOOKING AHEAD FORECAST-WISE...
EARLY THIS MORNING (THROUGH 12Z/7AM): CERTAINLY THE MAIN ISSUE IS
THE CONTINUING GRADUAL DECREASE IN THE COVERAGE OF MEASURABLE
RAIN...AS THE OVERALL AREA OF RAIN SLOWLY ENDS FROM PRIMARILY
WEST-TO-EAST AS INDIVIDUAL RAIN ELEMENTS STREAM FROM SOUTH-TO-
NORTH. WILL OBVIOUSLY BE CARRYING SOME PRETTY HEFTY EARLY MORNING
POPS IN EASTERN ZONES AND MUCH LOWER VALUES FAR WEST.
HOWEVER...GIVEN THE PRESENCE OF WIDESPREAD LOW STRATUS EVEN IN
AREAS WHERE MEASURABLE RAIN IS ENDING...COULD CERTAINLY SEE SOME
MAINLY NON-MEASURABLE LIGHT DRIZZLE SHOW ITS HAND AS WELL...SO
HAVE INCLUDED THIS MENTION IN WESTERN AREAS WHERE THE MEASURABLE
POP IS BELOW 20 PERCENT. WOULD NORMALLY BE A BIT MORE CONCERNED
ABOUT POTENTIALLY IMPACTFUL FOG DEVELOPING IN AREAS WHERE RAIN IS
ENDING...BUT WITH THE WIDESPREAD LOW STRATUS FIRMLY IN PLACE AND
LIGHT-BUT-STEADY BREEZES AM GOING TO HOLD OFF ON A FORMAL FOG
MENTION FOR NOW AND MONITOR TRENDS TO MAKE SURE AUTOMATED SITES DO
NOT START DROPPING BELOW 1 MILE...WHICH WOULD CERTAINLY JUSTIFY A
LAST-MINUTE FOG INCLUSION SHOULD THIS START OCCURRING.
TODAY (7AM-7PM): BY THE TIME 12Z/7AM ROLLS AROUND IN A FEW
HOURS...ANY LINGERING AREAS OF LIGHT MEASURABLE RAIN SHOULD
LARGELY BE CONFINED TO THE EASTERN HALF OF THE CWA...BUT EVEN THIS
SHOULD BE STEADILY PUSHING OUT WITH TIME...LEAVING ONLY A FEW
HOURS OF LIGHT DRIZZLE POTENTIAL IN ITS WAKE. WILL OBVIOUSLY
UPDATE AGAIN BEFORE SUNRISE BASED ON RADAR TRENDS...BUT FOR NOW WILL
CARRY ONLY A FEW HOURS OF LIKELY POPS IN EASTERN ZONES BEFORE
DROPPING DOWN TO ONLY SLIGHT 20 POPS IN EXTREME EASTERN COUNTIES
ALONG HWY 81 BY LATE MORNING (AGAIN THOUGH...SPOTTY DRIZZLE COULD
EXTEND BACK TO THE TRI-CITIES AREA WELL-PAST SUNRISE). ONCE
RAIN/DRIZZLE FINALLY ENDS...THE BIG QUESTION IS HOW QUICKLY/SLOWLY
DO CLOUDS VACATE FROM WEST-TO-EAST...AS THE MID LEVEL SHORTWAVE
TROUGH LIFTS AWAY FROM THE AREA INTO IA/MN...PROVIDING A BRIEF
PERIOD OF SHORTWAVE RIDGING FOR THIS AFTERNOON/EVENING. IF
ANYTHING...HAVE SLIGHTLY SLOWED DOWN THE CLEARING TREND FROM
PREVIOUS FORECAST...BUT AM COUNTING ON LIGHT WESTERLY LOW-LEVEL
FLOW TO GRADUALLY SCOUR OUT LOW STRATUS (OR AT LEAST TURN IT INTO
A SCATTERED COVERAGE) AS THE DAY WEARS ON. THAT BEING SAID...SOME
OF THE LATEST TRENDS IN 900-850MB RELATIVE HUMIDITY ALONG WITH SKY
COVER PROGS FROM THE LATEST HRRR SUGGEST THAT COUNTIES EAST OF
HIGHWAY 281 COULD HANG ONTO CONSIDERABLE CLOUD COVER WELL INTO THE
AFTERNOON WITH ANY APPRECIABLE CLEARING COMING LATE IN THE DAY.
THE BOTTOM LINE IS THAT ALTHOUGH CONFIDENCE IS NOT
OVERLY-HIGH...EXPECT SKY COVER TODAY IN THE WESTERN 1/2 OF THE
CWA TO IMPROVE FROM CLOUDY TO PARTLY CLOUDY/MOSTLY SUNNY...WHILE
THE EASTERN HALF ONLY IMPROVES FROM CLOUDY TO MOSTLY CLOUDY/PARTLY
CLOUDY. OBVIOUSLY THE CLOUD TRENDS WILL HAVE A DECENT IMPLICATION
ON HIGH TEMPERATURES THIS AFTERNOON. ALTHOUGH DID NOT FOLLOW
IT OUTRIGHT...DID TREND HIGHS TOWARD THE LATEST RAP13
NUMBERS...WHICH LOWERED VALUES GENERALLY 3-4 DEGREES IN MOST
CENTRAL/EASTERN COUNTIES...WHILE LEAVING WESTERN ZONES FAIRLY
SIMILAR TO PREVIOUS FORECAST. THE NET RESULT AIMS FROM NEAR-70 FAR
EAST...LOW-MID 70S TRI-CITIES AREA...AND UPPER 70S/LOW 80S FAR
WEST/SOUTHWEST. AS FOR WINDS TODAY...INITIALLY SOUTH/SOUTHEAST
BREEZES THIS MORNING WILL STEADILY BECOME MORE SOUTHWESTERLY IF
NOT WESTERLY AS THE DAY WEARS ON...BUT WITH SUSTAINED SPEEDS NOT
EXPECTED TO AVERAGE MORE THAN 10-15 MPH.
THIS EVENING/TONIGHT (7PM-7AM): IN SHORT...EXPECT A FAIRLY
TRANQUIL EVENING FOLLOWED BY A SOMEWHAT MORE ACTIVE LATE NIGHT
PERIOD WITH POTENTIALLY A FEW STRONG STORMS...ALTHOUGH CONFIDENCE
IS STILL A BIT LOW ON WHETHER THUNDERSTORM DEVELOPMENT WILL BE
MORE ISOLATED OR MORE WIDESPREAD. AS A RESULT...HAVE KEPT ALL
POST-MIDNIGHT POPS CAPPED AT NO HIGHER THAN 30-50 PERCENT FOR
NOW...AND WITH THE HIGHEST VALUES LARGELY FOCUSED OVER THE WESTERN
1/2 OF THE CWA. LOOKING ALOFT TO THE MID-UPPER LEVELS...A BRIEF
PERIOD OF SHORTWAVE RIDGING THIS EVENING WILL QUICKLY GIVE WAY TO
A LOW AMPLITUDE DISTURBANCE MOVING INTO THE CENTRAL PLAINS IN
SOUTHWEST FLOW ALOFT...ALONG THE VERY LEADING EASTERN EDGE OF THE
MAIN WESTERN CONUS TROUGH. ALTHOUGH THERE ARE THE TYPICAL VARIOUS
DEPICTIONS OF HOW CONVECTION WILL PLAY OUT TONIGHT AMONGST THE
VARIOUS DETERMINISTIC AND HIGHER-RES MODELS...GENERALLY TEND TO
PREFER THE DEPICTION OF THE 00Z NSSL 4KM-WRF AT THIS TIME. THIS
MEANS REASONABLY HIGH CONFIDENCE IN A DRY EVENING (PRE-
MIDNIGHT)...ALTHOUGH CONVECTION COULD ALREADY BE APPROACHING THE
CWA FROM SOUTHWEST NEB/SOUTHWEST KS AS IT FIRES UP ALONG THE NOSE
OF AN INCREASING 30-40KT LOW LEVEL JET EVIDENT AT 850MB. THEN
POST-MIDNIGHT...EXPECT ISOLATED TO SCATTERED SHOWERS/STORMS TO
MOVE INTO AND/OR DEVELOP DIRECTLY OVER THE CWA AS THE MID LEVEL
WAVE AND ASSOCIATED LOW LEVEL JET FORCING SPREADS FARTHER EAST.
COULD SEE A MORE CONCENTRATED ZONE OF CONVECTION THAT COULD
EVENTUALLY NECESSITATE LIKELY POPS...BUT JUST TOO TOUGH TO TELL
WHERE EXACTLY THIS WOULD BE YET. THAT BEING SAID...ALTHOUGH STORMS
WILL BE POSSIBLE ALMOST ANYWHERE BETWEEN MIDNIGHT-SUNRISE...THE
WESTERN HALF OF THE CWA SHOULD BE MOST FAVORED. AS FOR STORM
INTENSITY...THAT WILL OBVIOUSLY DEPEND HEAVILY ON THE DEGREE OF
ELEVATED INSTABILITY. AS IS COMMON...THE LATEST 06Z NAM SEEMS A
BIT HIGH WITH 850-700MB LAYER CAPE POTENTIALLY EXCEEDING 2500
J/KG...WHILE THE GFS LOOKS A BIT MORE REALISTIC BUT STILL HAS
ELEVATED CAPE INCREASING TO AROUND 1000 J/KG. ALTHOUGH DEEP LAYER
SHEAR IS PROGGED TO REMAIN FAIRLY WEAK AT ONLY AROUND 20-25KT AT
MOST...THIS INSTABILITY (ESPECIALLY IF THE NAM IS REMOTELY
CORRECT) COULD EASILY SUPPORT A FEW STRONG TO MARGINALLY SEVERE
HAIL CORES AT LEAST IN THE NICKEL-QUARTER RANGE. IN ORDER TO
REMAIN REASONABLY CONSISTENT WITH THE LACK OF AN OFFICIAL MARGINAL
RISK AREA ON THE INITIAL SPC DAY 1 OUTLOOK...WILL KEEP A FORMAL
SEVERE STORM MENTION OUT OF THE HAZARDOUS WEATHER OUTLOOK FOR
NOW...BUT WILL INTRODUCE A MENTION OF LATE-NIGHT STRONG STORM
POTENTIAL TO GET THE BALL TRENDING THAT DIRECTION. TURNING TO
OTHER ELEMENTS...BREEZES TONIGHT SHOULD GENERALLY AVERAGE 5-10 MPH
FROM THE SOUTHEAST AS A WEAK COLD FRONT STALLS OUT JUST NORTH OF
THE CWA THIS EVENING AND LOW PRESSURE DEVELOPS WEST. MADE VERY
LITTLE CHANGE TO LOW TEMPS...AIMING MOST OF THE CWA BETWEEN 57-61
DEGREES. ON ONE LAST NOTE...THE PRESENCE OF FAIRLY LIGHT SOUTHEAST
BREEZES LATE TONIGHT...AND FAIRLY CLOSE SURFACE TEMP/DEWPOINT
DEPRESSIONS ARGUE THAT FOG COULD POSSIBLY BECOME AN ISSUE IN SOME
AREAS...AND THIS HAS MODEST SUPPORT IN THE LATEST SREF VISIBILITY
PROGS. HOWEVER...GIVEN THAT CONFIDENCE IN IMPACTFUL FOG (GENERALLY
1 MILE VISIBILITY OR LESS) ISN/T EVEN THAT HIGH FOR THIS
MORNING...IT/S HARD TO PUT MUCH FAITH IN TRENDS FOR 24 HOURS FROM
NOW...SO WILL KEEP IT OUT OF THE FORECAST FOR NOW AND LET THE
FOCUS REMAIN ON THE THUNDERSTORM CHANCES.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 420 AM CDT THU MAY 14 2015
A FAIRLY ACTIVE WEATHER PATTERN IS EXPECTED THROUGH THE EXTENDED
PERIODS WITH SEVERAL CHANCES FOR SHOWERS AND THUNDERSTORMS AS THE
LOCAL AREA WILL BE INFLUENCED BY MULTIPLE UPPER LEVEL DISTURBANCES
TRACKING OUT OF THE DESERT SOUTHWEST AND INTO THE PLAINS.
OVERALL...TEMPERATURES WILL BE VERY MILD TO START THE
PERIOD...WITH A COLD FRONT DROPPING DOWN ACROSS THE LOCAL AREA
SUNDAY NIGHT/MONDAY...WHICH WILL RESULT IN TEMPERATURES DIPPING
BELOW NORMAL FOR THE FIRST HALF OF NEXT WEEK.
STARTING OFF FRIDAY MORNING...THE LOCAL AREA WILL LIKELY HAVE
ONGOING CONVECTION AS THE LLJ WILL BE POINTED TOWARDS THE LOCAL
AREA AND AN UPPER LEVEL DISTURBANCE IN SOUTHERLY FLOW ADVECTS
ACROSS THE LOCAL AREA. AS THIS CONVECTION TRACKS NORTH THROUGH THE
MORNING HOURS...THE POTENTIAL FOR REDEVELOPMENT IN THE WARM
SECTOR LOOKS FAVORABLE AS DEWPOINTS ARE FORECAST TO CLIMB TO NEAR
60...WHICH SHOULD HELP INSTABILITY VALUES TO SOAR ACROSS THE LOCAL
AREA. THESE INSTABILITY VALUES...COMBINED WITH AMPLE LOW LEVEL
SHEAR...SHOULD RESULT IN ORGANIZED CONVECTION DEVELOPING BY LATE
AFTERNOON...WITH MOST OF SOUTH CENTRAL NEBRASKA IN THE ENHANCED
RISK FOR SEVERE WEATHER ISSUED BY SPC. IF THUNDERSTORMS DO
DEVELOP...EXPECT THE POTENTIAL FOR LARGE HAIL...DAMAGING WIND
GUSTS AS WELL AS ISOLATED TORNADOES UNDER THIS SCENARIO.
AS THE LONGWAVE TROUGH THEN CROSSES THE ROCKIES ON SATURDAY...
EXPECT MULTIPLE UPPER LEVEL DISTURBANCES ROUNDING THE BASE OF THE
LONGWAVE TROUGH TO HELP TRIGGER ADDITIONAL CONVECTION ACROSS THE
LOCAL AREA. ONCE AGAIN...WITH ELEVATED DEWPOINTS ALONG WITH GOOD
CAPE VALUES AND MODEST SHEAR...EXPECT THE POTENTIAL FOR SEVERE
THUNDERSTORMS TO ONCE AGAIN BE POSSIBLE SATURDAY
AFTERNOON/EVENING...WITH JUST ABOUT THE ENTIRE FORECAST AREA NOW
HIGHLIGHTED FOR AN ENHANCED RISK OF SEVERE WEATHER.
CHANCES FOR CONVECTION WILL THEN CONTINUE INTO SUNDAY...WHEN AN
APPROACHING COLD FRONT SHOULD PUT AN END TO THIS MORE SIGNIFICANT
WEATHER...WITH COOLER AND MORE STABLE AIR ANTICIPATED IN ITS WAKE
TO START THE WORK WEEK. WHILE SHORTWAVE RIDGING ALOFT IS ALSO
FAVORED TO START THE WORK WEEK...YET ANOTHER UPPER LEVEL
DISTURBANCE IS FORECAST TO LIFT OUT OF THE SOUTHWEST AS EARLY AS
TUESDAY AFTERNOON...WHICH SHOULD BRING ADDITIONAL CHANCES FOR
SHOWERS AND THUNDERSTORMS ACROSS THE LOCAL AREA. WITH LESS
INSTABILITY TO WORK WITH...EXPECT THUNDERSTORM ACTIVITY FOR MID
WEEK TO BE MORE ISOLATED ACROSS THE REGION.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 606 AM CDT THU MAY 14 2015
ALTHOUGH CONFIDENCE REMAINS FAIRLY HIGH THAT A MULTI-HOUR PERIOD
OF VFR CEILING/VISIBILITY WILL MATERIALIZE BEYOND THE FIRST 6-8
HOURS OF THE PERIOD (POTENTIALLY LASTING WELL INTO THE
NIGHT)...MVFR/IFR CEILING AND VISIBILITY WILL CONTINUE TO BE THE
MAIN ISSUE THIS MORNING INTO EARLY THIS AFTERNOON...ALONG WITH A
FEW HOURS OF LIGHT DRIZZLE POTENTIAL. OBVIOUSLY TIMING IN THE
SPECIFICS OF THE RETURN TO VFR CONDITIONS IS SOMEWHAT
UNCERTAIN...BUT WILL CONTINUE TO AIM FOR VFR VISIBILITY BY LATE
MORNING AND VFR CEILING BY AROUND 20Z THIS AFTERNOON. DURING THE
LATTER HALF OF THE PERIOD...HAVE BROUGHT IN A VICINITY
THUNDERSTORM (VCTS) MENTION FOR LATE TONIGHT...WITH SOME SMALL
HAIL POSSIBLE SHOULD ANY OF THESE STORMS DIRECTLY AFFECT THE
TERMINALS. CANNOT RULE OUT SOME SUB-VFR CEILING/VISIBILITY AGAIN
TONIGHT AS WELL...BUT CONFIDENCE WAS NOT HIGH ENOUGH TO GO THERE
YET. WIND-WISE...FAIRLY LIGHT BREEZES ONLY AROUND 10KT OR LESS
SHOULD PREVAIL THROUGH THE PERIOD...WITH DIRECTION TRANSITIONING
FROM SOUTH RIGHT AWAY THIS MORNING...TO SOUTHWEST MOST OF THE
DAY...AND THEN SOUTHEAST THIS EVENING/TONIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...ROSSI
AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
809 AM PDT THU MAY 14 2015
.SYNOPSIS...UNSEASONABLY COOL AND UNSETTLED WEATHER IS EXPECTED
THROUGH SATURDAY AS A PACIFIC STORM SYSTEM IMPACTS THE REGION. RAIN
AND MOUNTAIN SNOW CAN BE EXPECTED AREA WIDE WITH NORTHERN AREAS
FAVORED ON THURSDAY AND SOUTHERN AREAS FAVORED ON FRIDAY. SOME
SCATTERED SHOWERS MAY LINGER ON SATURDAY BEFORE BRIEF IMPROVEMENT
ARRIVES SUNDAY. ANOTHER STORM SYSTEM WILL IMPACT THE REGION EARLY
NEXT WEEK WITH MORE SHOWER AND THUNDERSTORM CHANCES.
&&
.UPDATE...A QUICK UPDATE TO ADD SHOWERS/STORMS TO PORTIONS OF CLARK
COUNTY INCLUDING THE LV VALLEY UP THROUGH LINCOLN COUNTY BASED ON
LATEST RADAR TRENDS AND LIGHTNING DATA. -SALMEN-&&
.PREVIOUS DISCUSSION...256 AM PDT...
.SHORT TERM...THROUGH SATURDAY NIGHT.
THE CALENDAR MIGHT SAY MAY THE WEATHER PATTERN LOOKS MORE LIKE
FEBRUARY WITH AN ACTIVE PACIFIC JET STREAM BRINGING YET ANOTHER
STRONG TROUGH INTO THE SOUTHWEST. THIS STORM WILL IMPACT THE REGION
IN TWO DOSES WITH THE LEAD SHORTWAVE MOVING ONSHORE TODAY AS IT
ROTATES AROUND THE PARENT LOW...FOLLOWED BY THE PARENT LOW WHICH
MOVES ONSHORE IN SOUTHERN CALIFORNIA ON FRIDAY AND DRAGS EAST ACROSS
THE MOJAVE DESERT.
WIDESPREAD HIGH CLOUDS IN ADVANCE OF THIS LEAD SHORTWAVE HAVE
OVERSPREAD THE FORECAST AREA AND WILL CONTINUE TO ADVANCE INTO THE
REGION TODAY WITH CLOUD DECKS LOWERING THROUGH THE DAY. SHOWERS WILL
BREAK OUT FIRST ACROSS THE SIERRA WHERE SNOW LEVELS NEAR 6500 FEET
WILL LEAD TO THE LIKELIHOOD OF ACCUMULATING SNOW THURSDAY AFTERNOON.
WHILE ACCUMULATIONS BY SIERRA STANDARDS WONT BE TOO IMPRESSIVE...
BEING MID-MAY IT CERTAINLY MAY CATCH SOME OFF GUARD. ADDITIONAL
SHOWERS WILL BREAK OUT ACROSS NORTHERN MOHAVE COUNTY WHERE THE PAST
FEW RUNS OF THE HRRR HAVE BROKEN OUT SOME ISOLATED THUNDERSTORMS BY
EARLY AFTERNOON. BY LATER IN THE DAY THURSDAY ADDITIONAL SHOWERS
AND STORMS MAY FORM ACROSS PARTS OF THE MOJAVE DESERT AND EVEN MAY
CREEP INTO THE LAS VEGAS VALLEY. AMOUNTS IN THE DESERTS WILL
GENERALLY BE LIGHT...UNDER A TENTH OF AN INCH.
WINDS WILL AGAIN BE GUSTY TOMORROW AND I TOYED WITH THE IDEA OF A
WIND ADVISORY FOR THE WESTERN MOJAVE DESERT BUT WITH WIDESPREAD
OVERCAST...AND SOME SHOWER ACTIVITY...I DONT THINK MIXING WILL BE
OPTIMAL FOR AN ALREADY BORDERLINE WIND EVENT. SO I DECIDED AGAINST
ANY WIND HEADLINES.
BY FRIDAY...THE PRIMARY LOW MOVES ASHORE IN SOUTHERN CALIFORNIA. GFS
HAS BEEN FAIRLY CONSISTENT ON THE PAST SEVERAL RUNS NOW ON BRINGING
A HEALTHY STRIPE OF PRECIPITATION TO THE MOJAVE DESERT MAINLY SOUTH
OF INTERSTATE 40. QPF NUMBERS BY THE GFS ARE PRETTY SIGNIFICANT BY
MAY STANDARDS WITH 0.25 TO 0.50 INCH AMOUNTS ADVERTISED (KEEP IN
MIND MONTHLY AVERAGE RAINFALL THE ENTIRE MONTH OF MAY IN THIS PART
OF THE DESERT IS CLOSER TO A TENTH OF AN INCH). NAM IS MUCH DRIER
AND ECMWF KEEPS THE BRUNT OF THE MOISTURE FURTHER SOUTH....BUT I DO
LIKE THE GFS CONSISTENCY AND THE SOLUTION MAKES SOME METEOROLOGICAL
SENSE BUT THE NUMBERS ARE EXCESSIVE. I OPTED FOR A MIDDLE GROUND AND
RAISED POPS AND QPF ACCORDINGLY ACROSS THE MOJAVE DESERT ESPECIALLY
SOUTH OF I-40 BUT KEPT RAINFALL TOTALS UNDER A QUARTER OF AN INCH.
FURTHER NORTH PLACES LIKE LAS VEGAS WILL LIKELY SEE A COOL CLOUDY
DAY MUCH LIKE LAST FRIDAY WITH SOME LIGHT SHOWERS AROUND BUT AMOUNTS
AT THIS TIME AGAIN LOOK LIGHT. BE PREPARED FOR DRAMATICALLY COOLER
TEMPERATURES...LIKELY BEING 20 TO 30 DEGREES BELOW SEASONAL
AVERAGES.
ON SATURDAY THE TROUGH WILL DEPART TO THE EAST BUT SOME WRAP AROUND
MOISTURE AND INSTABILITY MAY STILL SPARK SOME CLOUDS AND SHOWERS
ESPECIALLY ACROSS THE SOUTHERN GREAT BASIN AND MOHAVE COUNTY IN
ARIZONA. OTHERWISE TEMPERATURES WILL CREEP UPWARD SLIGHTLY SATURDAY
BUT STILL BE AROUND 15 DEGREES BELOW NORMAL.
.LONG TERM...SUNDAY THROUGH THURSDAY.
SUNDAY...ATTENTION WILL TURN TO THE NEXT DEVELOPING CLOSED LOW OFF
THE CALIFORNIA COAST. SOUTH TO SOUTHWEST FLOW WILL STRENGTHEN AHEAD
OF IT LEADING TO SOUTHERLY SURFACE WINDS GENERALLY GUSTING 20-30 MPH
ACROSS THE FORECAST AREA SUNDAY AFTERNOON. BROAD UPWARD FORCING
AHEAD OF THE LOW WILL COMBINE WITH SOME LINGERING MOISTURE AND
INSTABILITY OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN ZONES
TO PRODUCE SOME AFTERNOON THUNDERSTORMS. THE UPPER LOW IS FORECAST
TO SWING INLAND MONDAY WITH SOME ADDITIONAL MOISTURE MOVING INTO
SOUTHERN NEVADA AND NORTHWEST ARIZONA. DIFFLUENT FLOW AND COOLING
ALOFT WILL HELP DESTABILIZE THE ATMOSPHERE AND LEAD TO MORE
EXTENSIVE COVERAGE AND MORE ORGANIZED BANDS OF CONVECTION EXTENDING
DOWN INTO CLARK AND MOHAVE COUNTIES MONDAY AFTERNOON.
THE UPPER LOW IS FORECAST TO LIFT UP ACROSS THE ROCKIES BY TUESDAY
LEAVING A WEAK BROAD TROUGH OVER THE WESTERN STATES THROUGH
THURSDAY. THE MEDIUM RANGE MODELS ARE ALL IN FAIRLY GOOD AGREEMENT
THAT THIS WILL PROVIDE A PATH FOR YET ANOTHER PACIFIC LOW PRESSURE
SYSTEM TO DROP INTO SOUTHERN NEVADA GOING INTO THE MEMORIAL DAY
WEEKEND. THIS PATTERN WILL KEEP TEMPERATURES SLIGHTLY BELOW NORMAL
THROUGH THE PERIOD WITH A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS
OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN. THEN...IT IS
LOOKING LIKE THERE WILL BE THE POTENTIAL FOR COOLER AND MORE
UNSETTLED WEATHER HEADING INTO THE MEMORIAL DAY WEEKEND.
&&
.AVIATION... FOR MCCARRAN...INCREASING CLOUDS AND LOWERING CEILINGS
EXPECTED TODAY AS A PACIFIC STORM IMPACTS THE REGION. SOUTH WINDS OF
15-25KT EXPECTED WITH GUSTS TO 30KTS BUT SOME VARIABILITY POSSIBLE
WHILE SHOWERS MOVE THROUGH THE VALLEY IN THE LATE AFTERNOON. CIGS
FALLING IN THE 8-10K FT RANGE THIS AFTERNOON AND EVENING. ADDITIONAL
RAIN AND REDUCED CIGS POSSIBLE FRIDAY.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...WIDESPREAD BKN-OVC CONDITIONS EXPECTED TODAY WITH CLOUD
DECKS LOWERING THROUGH THE DAY. SCT SHOWERS AND THUNDERSTORMS LIKELY
IN NORTHWEST ARIZONA AS WELL AS INYO COUNTY THROUGH MIDDAY...BEFORE
SPREADING INTO THE MOJAVE DESERT THURSDAY AFTERNOON. BEST CHANCES
FOR SHOWERS AND STORMS WILL BE NORTH OF INTERSTATE 40. ADDITIONAL
RAIN EXPECTED FRIDAY ESPECIALLY SOUTH OF A KDAG-KLAS-KSGU LINE.
BREEZY SOUTH WINDS OF 15-20KTS AND GUSTS TO 30KTS EXPECTED.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...OUTLER
LONG TERM...ADAIR
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
605 AM MDT THU MAY 14 2015
.AVIATION...
12Z TAF CYCLE
VFR CONDITIONS TO CONTINUE TO BE THE RULE THROUGH THE 12Z FRI...
BUT THERE WILL BE A FEW EXCEPTIONS. ONE WILL BE ACROSS FAR EAST
CENTRAL NM NEAR THE TX STATE LINE WHERE IFR AND POSS LIFR CIGS
WILL BE A POSSIBILITY TIL ABOUT 16Z TODAY AND THEN AFTER ROUGHLY
09Z FRI ACROSS AREAS MAINLY SOUTH OF INTERSTATE 40 AND FROM THE
PECOS RIVER VALLEY ON EAST. OTHERWISE...S TO SW LOW LEVEL FLOW TO
INCREASE LATE THIS MORN AND AFTN. HIGHEST TERMINAL FCST GUSTS
LIKELY TO BE AT KLVS THIS AFTN...IN THE VCNTY OF 34 TO 36KTS. A
FEW HIGH BASED AND GUSTY -SHRA AND -TSRA ACROSS NORTH AND FAR WEST
NM MAY IMPACT KFMN AND KGUP BETWEEN ABOUT 20Z AND 02Z. A LOWER
CHANCE FOR ISOLD TSRA ARE POSSIBLE LATE TODAY AS WELL...MAINLY
NEAR THE TX LINE...POSS IMPACTING KTCC.
43
&&
.PREV DISCUSSION...330 AM MDT THU MAY 14 2015...
.SYNOPSIS...
ACTIVE WEATHER PATTERN WILL CONTINUE FOR THE FORESEEABLE FUTURE.
SHOWERS AND THUNDERSTORMS WILL BE MOST NUMEROUS OVER THE NORTH AND
WEST TODAY THROUGH SATURDAY...AND A FEW STORMS NEAR THE TEXAS
BORDER MAY BE STRONG TO SEVERE THIS AFTERNOON AND EVENING AND FRIDAY
AFTERNOON AND EVENING. GUSTY SOUTHWEST WINDS WILL AFFECT NORTHEAST
NEW MEXICO FRIDAY AFTERNOON. SOME DRYING SATURDAY NIGHT INTO SUNDAY
THEN A WETTER PERIOD TO FOLLOW MONDAY NIGHT AND TUESDAY.
&&
.DISCUSSION...
WIDESPREAD HIGH CLOUDS ASSOCIATED WITH THE NEXT DISTURBANCE TO
AFFECT NEW MEXICO WILL PERSIST TODAY. PATCHY FOG AT KCAO KEEPS
VARYING AT WINDS FLOP AROUND...WITH MORE WIDESPREAD FOG TO THE NORTH
AND EAST. NOT EXPECTING THAT WILL HANG AROUND FOR VERY LONG THIS
MORNING. RUC SHOWING SOME LIGHT PRECIPITATION DEVELOPING THIS
MORNING OVER THE SRN HIGH TERRAIN SO MADE SOME ADJUSTMENTS FOR THAT.
SPC OUTLOOK BRINGS A MARGINAL AREA INTO THE FAR EAST CENTRAL/SE FOR
TODAY AND GENERALLY A SIMILAR AREA DRAWN FOR FRIDAY AS THE LEAD
DISTURBANCE EXITS. WINDS COULD BE GUSTY FRIDAY SOUTH AND EAST AS H7
WINDS INCREASE TO THE 30-40 KT RANGE. THE MAIN UPPER LOW/FRONT PASS
THROUGH FRIDAY NIGHT/SATURDAY. SOME BIG DISPARITIES POP GUIDANCE
WISE...TOOK A MIDDLE OF THE ROAD APPROACH...BUT IN GENERAL THEY ARE
HIGHER THAN WHAT WAS INHERITED. HIGHS FRIDAY THROUGH SUNDAY BELOW
AVERAGE OVER THE ENTIRE FORECAST AREA...ESPECIALLY SATURDAY...WITH
SOME WARMING SUNDAY. HIGHS STAY PRETTY MUCH NEAR TO BELOW AVERAGE
THROUGH THE MIDDLE OF NEXT WEEK AS YET ANOTHER UPPER LOW AND FRONT
BRING A WETTER PERIOD TO THE REGION MONDAY NIGHT AND TUESDAY.
&&
.FIRE WEATHER...
A FEW SHOWERS AND THUNDERSTORMS...NOT NEARLY AS HEAVY AS WHAT FELL
TUE AND EARLY WED...WILL DEVELOP ACROSS THE FAR NORTHERN PORTION OF
NM THIS AFTN...PRIMARILY ACROSS THE HIGHER TERRAIN. THE FAR WEST MAY
ALSO SEE ISOLATED AFTN AND EVE SHOWER OR STORM ACTIVITY...BUT
MEASURABLE RAINFALL IS UNLIKELY IN MOST CASES. FCST MODELS ARE STILL
PRETTY SUPPORTIVE OF ANOTHER ROUND OF WETTING MOISTURE FRIDAY INTO
SATURDAY AS ANOTHER VIGOROUS AND WET TROUGH ALOFT APPROACHES AND
MOVES ACROSS THE CENTRAL AND SOUTHERN ROCKIES. WETTING RAIN/HIGHER
ELEVATION SNOW WITH THIS SYSTEM IS EXPECTED TO FAVOR THE WESTERN
HALF OF NORTH AND CENTRAL NM...THOUGH THERE APPEARS TO BE SOME
INCREASE IN THE CHANCE FOR A FEW STRONG THUNDERSTORMS ACROSS THE
EAST HALF OF THE EASTERN PLAINS. CONFIDENCE REMAINS PRETTY HIGH AS
FCST MODELS HAVE BEEN GETTING MORE CONSISTENT ON THIS SCENARIO OVER
THE PAST SEVERAL MODEL RUNS. VENTILATION WILL BE EXCELLENT NEARLY
ALL AREAS THE NEXT 3 AFTNS DUE LARGELY TO THE STRONGER TRANSPORT
WINDS. MODEL DERIVED MIXING HEIGHTS STILL MAY BE A BIT TOO HIGH
GIVEN CLOUD COVER AND GENERALLY BELOW NORMAL TEMPS...SO THERE MAY
STILL BE A FEW MORE POCKETS OF VERY GOOD RATHER THAN EXCELLENT
VENTILATION THAN CURRENTLY INDICATED. RATES WILL DROP SHARPLY
SUN...BUT THEN PICK BACK UP SHARPLY AGAIN FOR EARLY TO MID WEEK NEXT
WEEK. SAT APPEARS TO BE THE COOLEST DAY WITH SNOW LEVELS AT THEIR
LOWEST... POSS GETTING AS LOW AS 8500 TO 9500 FEET ACROSS THE NORTH
AND WEST CENTRAL COUNTIES. FRI APPEARS TO BE THE WINDIEST DAY...
PARTICULARLY ACROSS THE NE THIRD OF THE FCST AREA.
STILL LOOKING AT A BREAK IN THE SHOWERY/COOLER WEATHER SUN INTO MUCH
OF MON WITH SOME SHORTWAVE RIDGING AHEAD OF ANOTHER PACIFIC TROUGH.
BACK DOOR COLD FRONT INTRUSION INTO AT LEAST THE EAST HALF OF THE
STATE SUNDAY NIGHT AND MON TO INCREASE MOISTURE SOME INITIALLY WITH
AN ADDED BOOST FROM GULF MOISTURE LATER MON INTO TUE SHOULD
ENCOURAGE DEVELOPMENT OF ANOTHER ROUND OF SHOWERS/THUNDERSTORMS...
MAINLY ALONG THE CENTRAL MOUNTAIN CHAIN ON EAST. BUT THERE IS ALSO
SOME POTENTIAL FOR SPOTTY ACTIVITY BETWEEN THE DIVIDE AND THE
CENTRAL MTN CHAIN AS MODELS MORE OFTEN THAN NOT KEEP THE MOISTURE
FARTHER EAST THAN WHAT IS OFTEN THE CASE. IN FACT SOME MODELS ARE
BEGINNING TO CREEP THE WETTING PRECIP FARTHER WEST ON MOST RECENT
COUPLE OF RUNS. THIS WESTWARD CREEP WILL CONTINUE TO BE MONITORED.
ANOTHER PACIFIC TROUGH SHOULD APPROACH THE AREA LATE NEXT WEEK. NOT
LOOKING AT ANY ORGANIZED CRITICAL FIRE WEATHER GROWING EVENTS NEXT
WEEK ALTHOUGH SUSPECT THERE WILL BE SOME AFTERNOON BREEZES. PRECIP
COVERAGE IS STILL UNCERTAIN...BUT AT THIS TIME LOOKS TO BE A LITTLE
FARTHER EAST THAN WHAT WAS THE CASE THIS PAST TUE/WED PERIOD.
43
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1028 AM CDT THU MAY 14 2015
.UPDATE...
ISSUED AT 1029 AM CDT THU MAY 14 2015
SURFACE LOW PRESSURE CENTERED OVER WESTERN NEBRASKA WITH A QUASI-
STATIONARY SURFACE FRONT EXTENDING FROM THE LOW NORTH-NORTHEAST
ACROSS THE CENTRAL DAKOTAS INTO NORTHEASTERN NORTH DAKOTA. STRONG
MID LEVEL S/WV TROUGH LIFTING ACROSS THE EASTERN DAKOTAS TOWARDS
THE UPPER MISSISSIPPI VALLEY REGION. SHOWERS...SOME AREAS
MODERATE...CONTINUE ALONG THE FRONTAL ZONE ACROSS SOUTH CENTRAL
NORTH DAKOTA INTO NORTHEASTERN NORTH DAKOTA THIS MORNING. RAINFALL
AMOUNTS WITHIN THE BAND HAVE GENERALLY BEEN IN THE RANGE OF
0.5-0.75"...WITH AMOUNTS IN EARLIER CONVECTIVE BANDS IN EXCESS OF
AN INCH.
SHOWERS WILL CONTINUE TO SLOWLY LIFT NORTH AND EAST AS THE DAY
PROGRESSES...AND SHOULD BE ENTIRELY OUT OF MY EASTERN COUNTIES BY
03Z.
OTHER UPDATE WITH THIS FORECAST PACKAGE WAS TO LOWER TEMPERATURES
CENTRAL AS LOW CLOUD COVER IS NOW FORECAST TO PERSIST THROUGH THE
AFTERNOON AS PER THE LAST FEW HIGH RES HRRR MODEL RUNS ALONG WITH
THE LATEST NAM/RAP LOW LEVEL RH FORECAST. STILL EXPECT CLEARING
WEST...THOUGH STRATUS FIELD IS EXTENSIVE. HIGH RES MODELS INDICATE
OVC CIGS TRENDING FEW-SCT 16-19Z ACROSS MY WEST...SO WILL MONITOR
IN CASE CLOUD COVER NEEDS TO BE INCREASED AND TEMPS DROPPED.
UPDATE ISSUED AT 640 AM CDT THU MAY 14 2015
SHOWERS CONTINUE TO LIFT SLOWLY NORTHWARD ACROSS CENTRAL AND
EASTERN NORTH DAKOTA. LATEST BOWMAN RADAR SHOWS RETURNS DRYING UP
OVER WESTERN NORTH DAKOTA...THUS CURRENT RADAR TRENDS LOOK GOOD.
OTHERWISE NO SIGNIFICANT UPDATES TO THE CURRENT FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM CDT THU MAY 14 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE WIDESPREAD
SHOWERS TODAY WITH SOME AREAS CENTRAL SEEING HEAVY RAINFALL.
CURRENTLY...AN UPPER LEVEL LOW/SHORTWAVE LIFTING NORTHEAST THROUGH
THE CENTRAL AND NORTHERN PLAINS WAS ASSOCIATED WITH WIDESPREAD
SHOWERS AND A FEW EMBEDDED THUNDERSTORMS ACROSS THE STATE. LIGHTNING
ACTIVITY HAD DECREASED IN THE LAST HOUR...AND MESOANALYSIS INDICATES
THAT CAPE HAS DECREASED ACROSS THE REGION. AT THE SURFACE...LOW
PRESSURE WAS OVER WYOMING WITH A WARM FRONT EXTENDING FROM THE LOW
NORTHEASTWARD TO NEAR FORT YATES TO NEAR DEVILS LAKE TO THE
NORTHEAST CORNER OF NORTH DAKOTA.
FORECAST CAPE VALUES FOR TODAY ARE LOW ENOUGH TO KEEP THE MENTION OF
THUNDER OUT OF THE FORECAST FOR THE DAYTIME PERIOD. PRECIPITABLE
WATER FORECASTS OF 1.00" TO 1.20" FOR SOUTH CENTRAL NORTH
DAKOTA...ALONG THE SURFACE WARM FRONT. WIDESPREAD AREAS OF 0.50" OF
RAIN ARE POSSIBLE TODAY ALONG AND EAST OF A LINE FROM THE TURTLE
MOUNTAINS TO BISMARCK/MANDAN TO GRANT COUNTY. LOCALLY HIGHER AMOUNTS
ARE POSSIBLE.
THE UPPER LEVEL SHORTWAVE AND SURFACE WARM FRONT ARE PROGGED TO MOVE
EAST TODAY. EXPECT SHOWERS TO DECREASE FROM WEST TO EAST
TODAY...LINGERING IN CENTRAL NORTH DAKOTA THIS AFTERNOON BEFORE
TAPERING OFF DURING THE EVENING HOURS. AS THE SURFACE WARM FRONT
MOVES EAST...HIGH PRESSURE IN SOUTH CENTRAL CANADA WILL PUSH
SOUTHWARD INTO THE STATE. HIGHS TODAY SHOULD RANGE IN THE 50S TO
LOWER 60S...WITH LOWS TONIGHT FROM THE UPPER 30S TO MID 40S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 346 AM CDT THU MAY 14 2015
STRONG VERTICALLY STACKED SYSTEM WILL INFLUENCE THE WEATHER ACROSS
THE NORTHERN PLAINS FRIDAY THROUGH SUNDAY. MAIN FORECAST ISSUES IN
THE LONG TERM ARE SEVERE POTENTIAL ON SATURDAY...PRECIPITATION
AMOUNTS AND POSSIBLE LOCALIZED FLOODING ISSUES THROUGH THE WEEKEND
AND THE POTENTIAL FOR FREEZING TEMPERATURES MONDAY TUESDAY
MORNINGS ON THE BACK SIDE OF THIS SYSTEM.
WE START OFF ON A QUIET NOTE FRIDAY AS THE UPPER LEVEL SYSTEM
TRACKS ACROSS THE INTER-MOUNTAIN WEST AND BEGINS TO TAKE SHAPE
OVER THE NORTHERN HIGH PLAINS. WE BEGIN THE DAY DRY WITH SURFACE
HIGH PRESSURE OVER THE FORECAST AREA. SOUTHEAST FLOW ALOFT WILL
INCREASE OVER WESTERN NORTH DAKOTA AS CYCLOGENESIS TAKES PLACE
OVER THE NORTHERN AND CENTRAL HIGH PLAINS. PRECIPITATION IS
EXPECTED TO DEVELOP BY AFTERNOON OVER THE SOUTHWEST AND BEGIN TO
SPREAD NORTH AND EAST.
FRIDAY NIGHT THROUGH SATURDAY MORNING...STRONG WARM ADVECTION
ENVELOPES WESTERN AND CENTRAL NORTH DAKOTA WITH A SURFACE AND
UPPER LOW DEVELOPING OVER NORTHEAST MONTANA. MODELS ARE PRETTY
SIMILAR IN BRINGING A BAND OF PRECIPITATION SOUTHWEST TO NORTHEAST
ACROSS THE FORECAST AREA FRIDAY NIGHT INTO SATURDAY MORNING...WITH
THE MAJORITY OF THE PRECIPITATION OVER THE NORTHERN TIER COUNTIES
ALONG THE DEFORMATION ZONE BY MIDDAY SATURDAY. INSTABILITY ALOFT
IS LIMITED INITIALLY BUT IS EXPECTED TO INCREASE DURING THE NIGHT
ACROSS NORTHERN SOUTH DAKOTA INTO SOUTHERN NORTH DAKOTA. MOST
UNSTABLE CAPES OF 500-1000 J/KG WITH 20-40KTS OF 0-6KM SHEAR LAY
ACROSS THE NORTHERN SOUTH DAKOTA BORDER LATE FRIDAY NIGHT INTO
EARLY SATURDAY MORNING. THUS A THREAT OF SEVERE WEATHER CAN NOT BE
RULED OUT DURING THIS PERIOD...BUT EXPECT THE BETTER THREAT WILL
REMAIN SOUTH OF THE BORDER.
SATURDAY AFTERNOON...POSSIBLY AS EARLY AS LATE SATURDAY MORNING
THE FIRST WAVE OF PRECIPITATION WILL HAVE MOVED THROUGH AND MODELS
SUGGEST A DRY SLOT WORKING INTO CENTRAL NORTH DAKOTA AS AN 80 KT
UPPER LEVEL JET PUSHES INTO EASTERN NORTH DAKOTA BY AROUND MIDDAY
SATURDAY. THIS SHOULD ALLOW FOR A DESTABILIZING ATMOSPHERE DURING
THE LATE MORNING AND AFTERNOON AS SURFACE TEMPERATURES RISE INTO
THE 70S ACROSS THE SOUTHERN HALF OF THE STATE. A STRONG SOUTHERN
STREAM JET OVER THE SOUTHWEST U.S. BEGINS LIFTING INTO THE
SOUTHERN AND CENTRAL PLAINS...ALLOWING THE NORTHERN STACKED SYSTEM
OVER EASTERN MONTANA TO BEGIN MOVING EAST. ALTHOUGH DIRECTIONAL
SHEAR IS NOT IMPRESSIVE...SUFFICIENT BULK SHEAR AND CAPE WILL BE
AVAILABLE DURING THE LATE MORNING THROUGH THE AFTERNOON THAT
SEVERE STORMS ARE POSSIBLE. WILL STILL NEED TO MONITOR TRENDS OF
THE NEXT DAY OR SO TO HOPEFULLY GET A BETTER IDEA.
SATURDAY NIGHT THROUGH SUNDAY...ANY SEVERE WEATHER THREAT SATURDAY
SHOULD QUICKLY DIMINISH FROM WEST TO EAST SATURDAY NIGHT INTO
SUNDAY MORNING AS THE SURFACE LOW CONTINUES TO TRACK EAST ACROSS
THE DAKOTAS. STRONG NORTHERLY FLOW WILL BRING MUCH COOLER
TEMPERATURES FROM WEST TO EAST SUNDAY...WITH MAINLY IN THE 40S
NORTH AND WEST...TO THE LOWER 60S SOUTHEAST. THE STRONG SOUTHERN
SHORTWAVE LIFTING THROUGH THE SOUTHERN AND CENTRAL PLAINS SATURDAY
MOVES INTO THE NORTHERN PLAINS SUNDAY AND MERGES WITH THE STACKED
SYSTEM TRACKING ACROSS THE DAKOTAS. BY SUNDAY AFTERNOON THE THREAT
OF SEVERE WEATHER WILL BE TO THE EAST OF THE DAKOTAS...BUT A BAND
OF PRECIPITATION IN THE DEFORMATION ZONE IS EXPECTED OVER EASTERN
AND POSSIBLY BACK INTO CENTRAL NORTH DAKOTA. THUS SOME PRETTY
HEFTY PRECIPITATION AMOUNTS COULD FALL OVER SOUTH CENTRAL INTO
NORTHEAST NORTH DAKOTA. WILL NEED TO MONITOR FOR SOME AREAS
RECEIVING ENOUGH RAIN TO PRODUCE LOCAL FLOODING ISSUES. ESPECIALLY
IF THEY GET HIT WITH PRECIPITATION A FEW TIMES BEFORE THIS.
PRECIPITATION FINALLY MOVES OUT OF THE AREA BY SUNDAY EVENING WITH
COLD HIGH PRESSURE BUILDING OVER THE AREA INTO EARLY NEXT WEEK.
WITH THE SURFACE HIGH MOVING INTO NORTH DAKOTA BY MONDAY MORNING
IT LOOKS LIKE A GOOD BET THAT WE WILL NEED A FROST ADVISORY OR
MORE LIKELY A FREEZE WARNING...IF CURRENT TEMPERATURE TRENDS HOLD.
WE COULD STILL BE DEALING WITH FROST ON TUESDAY MORNING AS WELL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 640 AM CDT THU MAY 14 2015
WIDESPREAD MVFR WITH LCL IFR CONDITIONS WILL CONTINUE TO SPREAD
OVER THE AREA WITH SHRA SPREADING NORTHWARD.
CONDITIONS WILL IMPROVE TO VFR OVER PORTIONS OF NORTHWEST NORTH
DAKOTA THURSDAY AFTERNOON...WHILE MOST AREAS WILL REMAIN IFR-MVFR.
KISN SHOULD SEE A RETURN OF MVFR-IFR AFT 02Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...JV
LONG TERM...TWH
AVIATION...JV
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
630 AM CDT THU MAY 14 2015
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 307 AM CDT THU MAY 14 2015
WATER VAPOR IMAGERY THIS MORNING SHOWS A VIGOROUS MID-LEVEL TROUGH
LIFTING NORTHEAST ACROSS THE PLAINS WHILE A RIDGE OF HIGH PRESSURE
EXTENDED N/S ACROSS OUR AREA. FORCING FROM THIS TROUGH WAS PRODUCING
A WIDESPREAD SWATH OF SHOWERS ACROSS EASTERN NEB/WESTERN IA...
PUSHING NORTHEAST TOWARD THE AREA. OTHERWISE...PLENTY OF HIGH/MID
CLOUD ACROSS THE FORECAST AREA WITH TEMPERATURES AT 2 AM RANGING
FROM THE LOWER/MID 40S ACROSS NORTHERN AND CENTRAL WI...TO THE
MIDDLE 50S ALONG AND WEST OF THE MISSISSIPPI RIVER.
LOOK FOR THAT MID-LEVEL TROUGH TO CONTINUE LIFTING NORTHEAST INTO
CENTRAL MN/IA BY LATE THIS AFTERNOON. GOOD AMOUNT OF 850-300MB PV-
ADVECTION AND 850MB MOISTURE TRANSPORT WILL CONTINUE TO FUEL SHOWERS
AS THEY SLOWLY PUSH INTO THE AREA FROM WEST TO EAST. DRIER LOWER
LEVELS ASSOCIATED WITH DEPARTING SURFACE HIGH PRESSURE WILL LIKELY
HOLD BULK OF THE SHOWERS WEST OF THE MISSISSIPPI RIVER THROUGH
NOON...BEFORE THEY OVERSPREAD THE REST OF THE AREA THROUGH THE
AFTERNOON HOURS. DUE TO THE CLOUDS AND INCOMING SHOWERS...
TEMPERATURES WILL SUFFER SOMEWHAT...RANGING FROM THE UPPER 50S TO
THE LOWER 60S.
SHOWERS WILL CONTINUE THROUGH MIDNIGHT ACROSS MOST OF THE
AREA...THEN START A SLOW DIMINISHING TREND FROM WEST TO EAST AFTER
MIDNIGHT AS THE TROUGH DEPARTS EAST AND RIDGING BUILDS IN FROM
MN/IA. OVERNIGHT LOWS ARE EXPECTED TO DIP INTO THE UPPER 40S TO THE
MIDDLE 50S.
APPEARS RAINFALL FROM THIS SYSTEM WILL BE SOMEWHERE IN THE 1/2 TO
3/4 INCH RANGE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 307 AM CDT THU MAY 14 2015
A FEW VERY LIGHT SHOWERS MAY BE ONGOING EARLY FRIDAY MORNING EAST OF
THE MISSISSIPPI RIVER EARLY IN THE MORNING AS THE TROUGH DEPART...
BUT SKIES ARE EXPECTED TO BECOME PARTLY CLOUDY BY AFTERNOON AS A
RIDGE OF HIGH PRESSURE WORKS INTO THE AREA. PLAN ON HIGHS IN THE
UPPER 60S THE THE LOWER 70S.
FOCUS THEN SHIFTS TO THE POTENTIAL FOR SOME STRONG TO SEVERE STORMS
THROUGH THE WEEKEND.
MODELS HAVE BEEN CONSISTENT IN PUSHING A WARM FRONT NORTHWARD
INTO/ACROSS THE AREA FRIDAY NIGHT THROUGH SATURDAY. INCREASING 850MB
MOISTURE TRANSPORT INTO/OVER THE WARM FRONT IS EXPECTED TO FUEL
SCATTERED THUNDERSTORM ACTIVITY. NAM SHOWING MUCAPE OF 1500-2000J/KG
LATE FRIDAY NIGHT INTO SATURDAY MORNING WITH 0-3KM SHEAR OF 20-25KT.
SO...LOOKS LIKE WE HAVE THE POTENTIAL TO GET A FEW STRONGER/MAINLY
PULSE TYPE THUNDERSTORMS AHEAD OF THE FRONT AS IT PUSHES NORTH
INTO/THROUGH THE AREA. THE FRONT LOOKS LIKE IT WILL PUSH NORTH OF
THE AREA BY LATE MORNING...LEAVING OUR AREA IN A WEAKLY CAPPED
ENVIRONMENT WITH WARM/HUMID AIRMASS IN PLACE. MAY HAVE TO WATCH
CLOSELY FOR SEVERE THUNDERSTORM POTENTIAL DURING THE AFTERNOON WHERE
NAM IS PRODUCING MUCAPE IN THE 3000-5000J/KG RANGE ALONG WITH 0-3KM
BULK SHEAR OF 25-30KT. NAM INSTABILITY MAY BE A BIT OVERDONE BASED
ON 70 DEGREE OUTPUT DEWPOINTS...BUT LOWER/MID 60S DEW POINTS LOOK
REALISTIC WHICH WOULD YIELD CAPE IN THE 2000-4000J/KG. LOOKS LIKE
HIGHEST SEVERE POTENTIAL WOULD BE WESTERN PORTIONS OF THE AREA WHERE
STEEPER MID-LEVEL LAPSE RATES/HIGHER-END OF THE BULK SHEAR WILL
EXIST. OTHERWISE...LOOK FOR HIGHS IN THE UPPER 70S TO THE LOWER 80S.
SHOWERS AND THUNDERSTORMS WILL LIKELY INCREASE IN COVERAGE FROM WEST
TO EAST SATURDAY NIGHT THROUGH SUNDAY AS FAIRLY STRONG SURFACE
CYCLOGENESIS TAKES PLACE OVER THE NORTHERN PLAINS...FUELING STRONGER
MOISTURE TRANSPORT/LIFT INTO THE AREA. CANNOT RULE OUT A FEW STRONG
TO SEVERE STORMS OVER WESTERN PORTIONS OF THE AREA SATURDAY NIGHT IN
DEEP SHEAR/HIGHER CAPE ENVIRONMENT. STRONG TO SEVERE STORM THREAT
CONTINUES SUNDAY AS A COLD FRONT PUSHES INTO THE AREA. EXTENT OF
SEVERE THREAT WILL BE DEPENDENT OF HOW MUCH THE ATMOSPHERE CAN
RECOVER FROM ONGOING CONVECTION AND TIMING OF THE FRONT. WILL
CONTINUE TO KEEP A CLOSE EYE ON THIS. TEMPERATURES SUNDAY ARE
EXPECTED TO TOP OFF IN THE MIDDLE/UPPER 70S.
AFTER THIS...BEGINNING OF THE NEW WORK WEEK LOOKS COOLER/DRIER
BEHIND THE DEPARTING LOW/COLD FRONT. PLAN ON HIGHS MONDAY AND
TUESDAY IN THE UPPER 50S TO THE LOWER 60S.
SHOWER/THUNDERSTORM CHANCES SPREAD INTO THE AREA AGAIN BY WEDNESDAY
IN WARM AIR ADVECTION AHEAD OF A TROUGH PUSHING OUT OF THE PLAINS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 630 AM CDT THU MAY 14 2015
MAIN AVIATION CONCERNS ARE MVFR/IFR CEILING CONDITIONS AND SHOWERS
MOVING INTO THE RST/LSE TAF SITES TODAY AND CONTINUE INTO TONIGHT.
AN UPPER LEVEL DISTURBANCE OVER NORTHEAST KANSAS...NORTHWEST
MISSOURI AND SOUTHWEST IOWA WILL LIFT NORTHEAST INTO THE GREAT LAKES
REGION TONIGHT. SOUTHERLY WINDS OUT AHEAD OF THE DISTURBANCE WILL
ADVECT LOW LEVEL MOISTURE INTO THE REGION AND LOWER CEILING
HEIGHTS TODAY AT THE LSE/RST TAF SITES. THE LATEST 14.06Z NAM AND
14.09Z RAP SHOW CEILING HEIGHTS LOWERING TO IFR CONDITIONS AT RST
TAF SITE BY 21Z TODAY AND TO MVFR AT LSE BY 23Z TODAY. WITH THE
UPPER LEVEL DISTURBANCE PULLING AWAY TO THE EAST OF THE AREA AND
LIGHT RAIN/SHOWERS ENDING TONIGHT...THE LATEST 14.06Z GFS/NAM
HINT AT IMPROVING CONDITIONS AT RST/LSE TAF SITES AFTER 06Z
FRIDAY. HOWEVER...THE 14.06Z GFS/NAM BUFKIT SOUNDINGS INDICATE
NEAR SURFACE BOUNDARY LAYER RESIDUAL MOISTURE DURING THIS TIME
FRAME. WILL CONTINUE TREND OF MVFR/IFR CEILING CONDITIONS AT
RST/LSE TAF SITES AFTER 06Z FRIDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...DTJ
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
551 AM MDT THU MAY 14 2015
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 300 AM MDT THU MAY 14 2015
FOG HAS FORMED OVER THE PAST FEW HOURS IN THE NORTH PLATTE VALLEY
AND ACROSS PORTIONS OF THE NEBRASKA PANHANDLE. WITH REALLY LIGHT
WINDS THE HRRR KEEPS LIFR CONDITIONS THRU 13Z SO INCLUDED SOME
PATCHY FOG INTO THE MID MORNING. OVERALL...SHOWER ACTIVITY WILL BE
QUITE A BIT LESS THIS AFTN COMPARED TO YESTERDAY. A SHORTWAVE
RIDGE WILL MOVE OVERHEAD THROUGH THE AFTN AND LLVL MOISTURE IS NOT
ALL THAT IMPRESSIVE. THE MODELS KEEP ISOLATED CONVECTION CONFINED
TO AREAS ALONG AND WEST OF THE LARAMIE RANGE THROUGH 00Z. UPPER
LEVEL DIVERGENCE WILL INCREASE AFTER 00Z AS A SHORTWAVE EJECTS
NORTHWARD ON THE EAST SIDE OF THE UPPER LOW OVER CALIFORNIA. WITH
GOOD MIDLVL ISENTROPIC ASCENT AND SOME ELEVATED CAPE...THIS IS
ACTUALLY A SITUATION WHERE SHOWER AND TSTM COVERAGE COULD BE
GREATER INTO THE NIGHT...ESPECIALLY OVER THE NORTHEASTERN HALF OF
THE CWA. THUS...KEPT THE 30-40 POPS GOING THROUGH EARLY FRI
MORNING. SOUTHEASTERLY SFC WINDS WILL CONTINUE TO ADVECT HIGHER
DEWPOINTS INTO THE PLAINS THROUGH THE NIGHT.
THE MOST IMPACTFUL EVENT IN THE SHORT TERM IS STILL LOOKING LIKE
THE CHANCE OF SEVERE STORMS ACROSS THE NEBRASKA PANHANDLE ON FRI.
OVER THE PAST FEW DAYS THE MODELS HAVE BEEN CONSISTENT AT SHOWING
THE COMBINATION OF INSTABILITY (CAPE VALUES OF 1500-1750 J/KG) AND
DEEP LAYER SHEAR (40-45 KTS) TO SUPPORT SUPERCELLS ALONG AND NORTH
OF THE WARM FRONT. THE MAIN QUESTION WILL BE JUST WHERE THE SFC
LOW AND ASSOCIATED WARM FRONT ARE LOCATED BY MIDDAY. TEND TO
PREFER THE NAM AND ECMWF SOLNS THAT INDICATE EAST WINDS CONTINUING
ACROSS MUCH OF THE PANHANDLE THRU THE AFTN...AS OPPOSED TO THE GFS
THAT PUSHES WESTERLY WINDS AND DRIER DEWPOINTS ACROSS THE ENTIRE
PANHANDLE BY 00Z. OF COURSE WILL ALSO HAVE TO WATCH AND SEE
WHETHER THE SFC LOW IS FURTHER WEST TOWARD THE LARAMIE RANGE AS
THIS WOULD PUSH THE SVR THREAT INTO SOUTHEAST WY. WHILE LARGE HAIL
WOULD LIKELY BE THE PRIMARY THREAT...THE LLVL SHEAR PARAMETERS DO
SHOW THE POTENTIAL FOR SOME WEAK TORNADOES ESPECIALLY ALONG AND
JUST NORTH OF THE WARM FRONT WHERE WINDS WILL BE BACKED THE MOST.
NAM HODOGRAPHS ARE PRETTY IMPRESSIVE WITH 0-3 KM HELICITY OF
250-300. LCL HEIGHTS ARE RATHER LOW ALSO. THE DAY 2 SPC OUTLOOK
HAS NOT CHANGED MUCH WITH MOST OF THE PANHANDLE IN A SLIGHT
RISK...AND THE ENHANCED RISK IS JUST OFF TO THE EAST INTO NORTH
PLATTES CWA. IT WILL DRY OUT QUICKLY BY FRI EVENING AS THE SFC LOW
AND WARM FRONT PUSH NORTHWARD INTO THE DAKOTAS. WITH QUITE A BIT
LESS LLVL MOISTURE AND INSTABILITY TO WORK WITH ON
SAT...CONVECTION WILL BE WEAKER AND LESS WIDESPREAD. THE UPPER
LEVEL SYSTEM WILL MOVE INTO THE CENTRAL PLAINS BY SAT NIGHT WITH A
COLD FRONT PUSHING ACROSS THE REGION.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 300 AM MDT THU MAY 14 2015
AN ACTIVE WEATHER PATTERN SHOULD PERSIST WITH LARGE SCALE
TROUGHING REMAINING INTACT OVER THE WESTERN CONUS. SOME LINGERING
SHOWERS AND TSTMS CAN BE EXPECTED ON SUN/SUN NIGHT AS A STRONG
/NEGATIVELY-TILTED MID-LEVEL SHORTWAVE LIFTS NORTHEAST INTO THE
DAKOTAS. THE PROJECTED TRACK OF THIS SYSTEM AND H7-H3 PROGS FROM
THE GFS/ECMWF SUGGEST THAT AREAS ALONG THE I80 CORRIDOR BETWEEN
CYS AND SNY WOULD SEE LESS PCPN WITH A POTENTIAL DRY SLOT ALOFT. A
TRANSITORY RIDGE WILL TEMPORARILY QUIET THINGS DOWN ON MON WITH
WEAK SUBSIDENCE AND SOME DRYING IN THE MID LEVELS. THE GFS HAS
COME INTO LINE WITH THE ECMWF ON TUE SHOWING WIDESPREAD LLVL
UPSLOPE DEVELOPING EAST OF THE LARAMIE RANGE AHEAD OF THE NEXT
SYSTEM LIFTING INTO THE DESERT SW. THE LATEST SUITE OF MEDIUM
RANGE MODEL GUIDANCE SHOWS QPF VALUES UP TO AN EXCEEDING ONE INCH
BETWEEN TUE NIGHT AND WED. THIS MAKES SENSE WITH LLVL FORCING
BENEATH INCREASINGLY DIFLUENT FLOW ALOFT AND A COUPLED H25 JET.
THE EURO IS CONSIDERABLY COLDER THAN THE GFS...SHOWING H7 TEMPS
FALLING TO BETWEEN -2 AND -4 DEG C BY 12Z WED. WHILE WARM
ADVECTION IN LLVL EASTERLY/UPSLOPE FLOW MAKES THIS QUESTIONABLE
AT THIS RANGE...WOULD NOT BE ENTIRELY SURPRISED TO SEE PCPN CHANGE
TO SNOW AT SOME POINT DURING THIS EVENT...AT LEAST FOR HIGHER
ELEVATIONS. POTENTIAL FOR CONVECTION WILL EXIST VIRTUALLY EVERY
DAY WITH SLIGHTLY NEGATIVE LIFTED INDEX VALUES EACH AFTN THROUGH
WED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 545 AM MDT THU MAY 14 2015
AREAS OF FOG WILL CONTINUE TO RESULT IN LOCALIZED IFR CONDITIONS
AT KAIA/KBFF THROUGH ABOUT 13-14Z. OTHERWISE VFR CONDITIONS ARE
EXPECTED AT ALL TERMINALS THROUGH MUCH OF THE DAY. SHOWER AND
TSTM CHANCES WILL INCREASE AFTER 19Z OVER SOUTHEAST WY...AND THEN
AFTER 00Z FRI OVER WESTERN NE. CONVECTION COULD BE ACCOMPANIED BY
GUSTY AND ERRATIC WINDS AND LOCALLY MVFR CIGS/VSBYS. LOW CIGS
SHOULD BECOME MORE WIDESPREAD OVER THE WESTERN PANHANDLE BETWEEN
06-12Z FRI.
&&
.FIRE WEATHER...
ISSUED AT 300 AM MDT THU MAY 14 2015
NO FIRE WEATHER CONCERNS THROUGH THE WEEKEND. TODAY WILL BE THE
WARMEST DAY WITH MINIMUM AFTERNOON HUMIDITY VALUES FALLING TO
25-30 PERCENT AT SOME LOCATIONS. SHOWERS AND THUNDERSTORMS WILL
BECOME MORE WIDESPREAD BY LATE TONIGHT INTO FRIDAY AND COOLER
TEMPERATURES WILL OCCUR INTO THE WEEKEND. FUELS ARE ALSO IN FULL
GREEN UP AFTER THE RECENT WET PERIOD.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...ZF
LONG TERM...CLH
AVIATION...CLH
FIRE WEATHER...ZF
AREA FORECAST DISCUSSION
NWS TUCSON AZ
950 AM MST THU MAY 14 2015
.SYNOPSIS...STRONG AND GUSTY WINDS WILL OCCUR INTO FRIDAY AHEAD OF A
STRONG LOW PRESSURE SYSTEM APPROACHING FROM THE WEST. THIS SYSTEM
WILL ALSO BRING A GOOD CHANCE OF SHOWERS...ISOLATED THUNDERSTORMS
AND COOLER TEMPERATURES FRIDAY INTO SATURDAY. EXPECT DRY CONDITIONS
AND MUCH WARMER TEMPERATURES EARLY NEXT WEEK.
&&
.DISCUSSION...IR/VISIBLE SATELLITE IMAGERY INDICATED MOSTLY CLOUDY
SKIES DUE TO CIRRIFORM CLOUDS FROM THE TUCSON METRO AREA EWD TO THE
NEW MEXICO BORDER. CLEARING SKIES WERE NOTED ACROSS THE TOHONO
O`ODHAM NATION...BUT CUMULOFORM CLOUDS HAD DEVELOPED DURING THE PAST
HOUR OR SO ACROSS FAR WRN PIMA COUNTY. SURFACE WINDS VALID 16Z WERE
GENERALLY SLY AT 10-20 MPH WITH GUSTS TO NEAR 30 MPH.
DEEP UPPER TROUGH NEAR THE WEST COAST WITH A TIGHT MID-LEVEL
PRESSURE GRADIENT ACROSS SE ARIZONA WILL PRODUCE WINDY CONDITIONS
TODAY. A WIND ADVISORY IS IN EFFECT UNTIL 7 PM MST THIS EVENING FOR
LOCATIONS SE OF TUCSON. PLEASE REFER TO AWIPS PRODUCT PHXNPWTWC /WMO
HEADER WWUS75 KTWC/ FOR FURTHER DETAIL. OTHERWISE...PRECIP-FREE
CONDITIONS WILL OCCUR TODAY AHEAD OF THIS STRONG LOW PRESSURE
SYSTEM.
BASED ON THE 14/12Z NAM/GFS AND RUC HRRR SOLUTIONS... THERE ARE NO
UPDATES PLANNED AT THIS TIME. PLEASE REFER TO THE ADDITIONAL
SECTIONS FOR FURTHER DETAIL.
&&
.AVIATION...VALID THRU 15/18Z.
EXPECT A FEW TO SCATTERED CLOUDS AT 6-12K FT AGL AND BROKEN TO
OVERCAST CLOUD DECKS ABOVE 20K FT AGL INTO FRIDAY MORNING. STRONG
AND GUSTY WINDS WILL OCCUR TODAY. SURFACE WIND THE REST OF THIS
MORNING WILL BE SLY/SWLY AT 14-22 KTS WITH GUSTS OF 25-35 KTS...THEN
SPEEDS INCREASING TO 20-30 KTS WITH GUSTS OF 35-40 KTS THIS
AFTERNOON. SURFACE WIND DECREASING THIS EVENING THOUGH THERE WILL BE
AN INCREASED SLY/SWLY COMPONENT OVERNIGHT...ESPECIALLY NEAR KDUG AND
KFHU. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...A STRONG STORM SYSTEM WILL APPROACH AND MOVE ACROSS
THE REGION RESULTING IN STRONG AND GUSTY WINDS TODAY AND
FRIDAY...FOLLOWED BY A CHANCE OF SHOWERS AND THUNDERSTORMS LATE
FRIDAY INTO SATURDAY. ALTHOUGH WINDY CONDITIONS ARE EXPECTED ACROSS
MUCH OF THE AREA TODAY AND FRIDAY...THE STRONGEST WINDS WILL OCCUR
ACROSS COCHISE COUNTY.
WIND SPEEDS ARE EXPECTED TO EXCEED CRITICAL FIRE WEATHER THRESHOLDS
TODAY. HOWEVER...MINIMUM RELATIVE HUMIDITY VALUES WILL BE BORDERLINE
TODAY...AND THEN INCREASING MOISTURE IS EXPECTED ON FRIDAY. CRITICAL
FIRE WEATHER CONDITIONS MAY BE BRIEFLY MET FOR AN HOUR OR TWO THIS
AFTERNOON AT THE LOWER ELEVATIONS...ALTHOUGH WIDESPREAD AND/OR LONG
LIVED CONDITIONS ARE NOT EXPECTED. EXPECT DRY CONDITIONS WITH MUCH
WARMER TEMPERATURES EARLY NEXT WEEK.
&&
.PREV DISCUSSION...MODELS INDICATE THAT THE LOW PRESSURE SYSTEM OFF
THE CALIFORNIA COAST WILL CONTINUE MOVING EAST TODAY...WITH A VORT
MAX ROTATING THROUGH THE BASE OF THE TROUGH ACROSS WESTERN ARIZONA
BY LATE THIS AFTERNOON. AS A RESULT...EXPECTING A CONSIDERABLE
INCREASE IN WINDS TODAY IN ADVANCE OF THIS SYSTEM. THAT SAID...A
WIND ADVISORY WAS ALREADY HOISTED BY THE DAY SHIFT YESTERDAY. A WIND
ADVISORY IS ALSO IN EFFECT FOR FRIDAY AS WELL FOR THE SAME GENERAL
AREA...ALTHOUGH SLIGHTLY MORE REAL ESTATE FARTHER TO THE WEST THAN
TODAY. EVEN THOUGH WINDS WILL EASILY EXCEED RED FLAG CRITERIA FOR
MOST AREAS TODAY...THE MINIMUM RELATIVE HUMIDITIES STILL WILL BE THE
FACTOR THAT LIMITS DURATIONS THAT RED FLAG CONDITIONS WILL BE MET
TODAY (FOR MORE INFO SEE THE FIRE WEATHER SECTION).
THE PRECIPITATION WILL BEGIN EARLY FRIDAY WITH JUST ISOLATED
MOUNTAIN ACTIVITY THROUGH THE MORNING HOURS. BY THE EVENING HOURS ON
FRIDAY EXPECT SCATTERED DESERT/VALLEY SHOWERS AND ISOLATED
THUNDERSTORMS...WHILE THE MOUNTAINS WILL SEE GOOD CHANCE TO NUMEROUS
SHOWERS AND SNOW SHOWERS. FOR THE OVERNIGHT PERIOD FROM MIDNIGHT
FRIDAY NIGHT TO AROUND SUNRISE SATURDAY...EXPECT NUMEROUS SHOWERS
AND ISOLATED THUNDERSTORMS FROM NORTH OF NOGALES THROUGH THE TUCSON
METRO AND NORTH AND EAST TOWARD PINAL...GRAHAM AND GREENLEE
COUNTIES. BY SATURDAY MORNING AND CONTINUING THROUGH LATE SATURDAY
PRECIPITATION CHANCES WILL CONTINUE TO DECREASE WITH A RETURN TO DRY
WEATHER BY SATURDAY NIGHT INTO SUNDAY. SOME SNOW IN THE HIGHER
ELEVATIONS EXPECTED WITH THIS SYSTEM AS SNOW LEVELS FALL TO AROUND
7000-7500 FEET BY EARLY SATURDAY MORNING. SNOW AMOUNTS EXPECTED TO
BE THE GREATEST OVER THE WHITE MOUNTAINS WITH NEARLY 5 INCHES
EXPECTED AND ONLY 2 TO 4 INCHES FOR THE SANTA CATALINA AND RINCON
MOUNTAINS OF EASTERN PIMA COUNTY AND THE GALIURO AND PINALENO
MOUNTAINS OF GRAHAM COUNTY.
DRY WEATHER RETURNS SUNDAY AND WILL CONTINUE THROUGH THE MIDDLE OF
NEXT WEEK WITH A SLIGHT WARMING TREND BEGINNING ON SUNDAY.
FOR TUCSON...HIGH TEMPERATURES GENERALLY 6 TO 8 DEGS BELOW NORMAL
TODAY...THEN 15 TO NEAR 20 DEGS BELOW NORMAL FOR FRIDAY AND
SATURDAY. THEREAFTER...HIGHS AROUND 4 TO 7 DEGS BELOW NORMAL. LOW
TEMPS WILL BE BELOW NORMAL THROUGH THE ENTIRE FORECAST
PERIOD...ALTHOUGH THE COOLEST MORNINGS WILL OCCUR OVER THE
WEEKEND...WHEN THEY WILL RANGE FROM 6 TO 8 DEGS BELOW NORMAL.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 7 PM MST THIS EVENING FOR AZZ507-508-512-513.
WIND ADVISORY FROM NOON TO 7 PM MST FRIDAY FOR AZZ503-507-508-
511>513-515.
&&
$$
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AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
908 AM PDT THU MAY 14 2015
.SYNOPSIS...A SYSTEM TO OUR WEST WILL PRODUCE SHOWERS AND POSSIBLE
THUNDERSTORMS TODAY INTO THE EVENING ESPECIALLY FOR LOCATIONS
SOUTH OF SAN FRANCISCO. A FEW SHOWERS MAY LINGER INTO FRIDAY
MORNING. DRY WEATHER WILL RETURN BY FRIDAY AFTERNOON AND WILL
LIKELY CONTINUE THROUGH THE WEEKEND AND WELL INTO NEXT WEEK.
TEMPERATURES WILL BE COOLER THAN NORMAL THROUGH THE PERIOD.
&&
.DISCUSSION...AS OF 9:08 AM PDT THURSDAY...LOCAL RADAR IS SHOWING
SHOWERS OVER THE COASTAL WATERS THAT ARE SLOWLY MOVING EASTWARD
TOWARDS THE COAST. THERE HAVE BEEN A FEW LIGHTNING STRIKES WEST OF
THE MONTEREY/SAN LUIS OBISPO COUNTY LINE DURING THE PAST HOUR.
EXPECT SHOWER ACTIVITY TO MOVE ONSHORE LATER THIS MORNING WITH A
SLIGHT CHANCE OF THUNDERSTORMS THROUGH THE EVENING. RAINFALL
TOTALS ARE NOT EXPECTED TO BE LARGE...UP TO A THIRD OF AN INCH
IS POSSIBLE...BUT COULD TOP OUT AROUND A HALF INCH IN AREAS OF
HEAVIER SHOWERS...MAINLY OVER COASTAL MONTEREY COUNTY. THE HRRR IS
STILL INDICATING VERY SPOTTY RAINFALL AMOUNTS WITH SOME AREAS IN
THE EAST BAY POSSIBLY GETTING UP TO A HALF INCH. THE MOST LIKELY
SCENARIO IS A FEW SPOTS WILL GET MUCH MORE THAN EXPECTED WHILE
OTHER PLACES GET LITTLE TO NO RAINFALL. SHOWERS ARE EXPECTED TO LINGER
INTO THE OVERNIGHT HOURS AND SLOWLY DIMINISH ON FRIDAY.
THE UPPER LOW WILL CONTINUE TO MOVE TO THE SOUTH ON FRIDAY WITH
RAIN MOVING INLAND OVER THE LOS ANGELES BASIN FRIDAY MORNING. OUR
AREA WILL SEE COOL TEMPERATURES THROUGH THE WEEKEND AS A LONG-WAVE
TROUGH REMAINS OVER THE WEST. THIS TROUGH PATTERN WILL MAINTAIN
THROUGH NEXT WEEK AS WELL WITH A FEW IMPULSES MOVING THROUGH FROM
TIME TO TIME. RIGHT NOW NONE OF THESE ARE EXPECTED TO BRING ANY
PRECIPITATION TO THE AREA...HOWEVER...COOLER THAN NORMAL
TEMPERATURES WILL BE THE RULE.
&&
.AVIATION...AS OF 4:30 AM PDT THURSDAY...CLOUDS ARE LOWERING WITH
THE APPROACH OF AN UPPER LEVEL LOW. RADAR IS STARTING TO DETECT
LIGHT SHOWERS OFF THE COAST AND THESE WILL MOVE INTO THE COAST BY
MID MORNING AND INLAND LATE MORNING. WINDS WILL BE LIGHT SOUTHERLY
THIS MORNING BUT WILL SWITCH TO WESTERLY IN THE AFTERNOON.
VICINITY OF KSFO...MVFR CIGS. SHOWERS AFTER 16Z. SOUTHEAST WINDS
5-10 KT SWITCHING TO THE WEST AFTER 20Z. CLOUDS DECREASING AFTER 02Z.
KSFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS...MVFR CIGS. SHOWERS AFTER 15Z. CLOUDS
DECREASING AFTER 01Z.
&&
.MARINE...AS OF 08:21 AM PDT THURSDAY...A 1010 MB LOW OFF THE
NORTHERN CALIFORNIA COAST WILL TRACK SOUTHWARD BRINGING A SLIGHT
CHANCE OF THUNDERSTORMS TODAY AND TONIGHT. NORTHWEST WINDS WILL
INCREASE FRIDAY AND SATURDAY AS THE LOW MOVES INLAND OVER SOUTHERN
CALIFORNIA AND HIGH PRESSURE BUILDS OFF THE CALIFORNIA COAST.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TDAY...NONE.
$$
PUBLIC FORECAST: SIMS
AVIATION: W PI
MARINE: LARRY
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AREA FORECAST DISCUSSION
NWS LINCOLN IL
207 PM CDT THU MAY 14 2015
.SHORT TERM...(TONIGHT)
ISSUED AT 206 PM CDT THU MAY 14 2015
SHOWERS THUS FAR HAVE CONTINUED TO BATTLE A VERY DRY AIRMASS OVER
CENTRAL ILLINOIS. HOWEVER...A MORE ROBUST AREA OF SHOWERS ASSOCIATED
WITH THE UPPER LOW CURRENTLY TRACKING ACROSS NORTHERN MISSOURI WILL
BE ARRIVING IN THE ILLINOIS RIVER VALLEY BY MID AFTERNOON. THE HRRR
MODEL...WHICH HAS BEEN DOING A DECENT JOB THUS FAR...SHOWS SOME
ADDITIONAL DEVELOPMENT WEST OF I-55 LATE AFTERNOON INTO THE
EVENING... AND HAVE CONCENTRATED THE HIGHER POP`S IN THESE AREAS.
HIGHER-RESOLUTION MODELS SUCH AS THE HRRR AND NMM/ARW AGREE WITH THE
NAM SOLUTION OF THE EVOLUTION OF A MORE EAST-WEST CONFIGURATION OF
SHOWERS ROUGHLY CENTERED ALONG I-72 BY MIDNIGHT. THUNDER UPSTREAM IN
MISSOURI HAS BEEN MINIMAL THUS FAR...AND INSTABILITY PARAMETERS OFF
THE NAM...RAP AND ARW SUGGEST ANY THUNDER IN OUR AREA WOULD BE MOST
LIKELY ALONG AND WEST OF I-55 TONIGHT.
NOT MUCH OF A DROPOFF EXPECTED IN TEMPERATURES TONIGHT...GENERALLY
REMAINING STEADY IN THE LOWER 60S.
&&
.LONG TERM...(FRIDAY THROUGH THURSDAY)
ISSUED AT 206 PM CDT THU MAY 14 2015
IN THE WAKE OF THE WAVE MOVING ACROSS THE MIDWEST TODAY...HEIGHTS
BUILD BRIEFLY AHEAD OF NEXT WEAKER WAVE MOVING NORTHEAST AROUND WEST
COAST CLOSED LOW. HOWEVER, MODELS ARE CONSISTENT IN REDEVELOPING THE
WARM FRONT OVER CENTRAL ILLINOIS FRIDAY AND WITH THE WEAKER WAVE
APPROACHING FRIDAY AFTERNOON, THUNDERSTORMS WILL LIKELY DEVELOP.
WILL NEED TO RETAIN AT LEAST LOW POPS DESPITE THE RIDGING.
INSTABILITY OF 1500-2000 J/KG WILL BE POSSIBLE ALONG AND TO THE
SOUTH OF THE FRONT IN AREAS THAT SEE A LITTLE SUN THOUGH SHEAR WILL
BE QUITE LIMITED.
AS SOUTHERLY FLOW BECOMES ESTABLISHED...DEW POINTS WILL RESPOND BY
CLIMBING INTO THE 60S FOR FRIDAY AFTERNOON AND THE WEEKEND. AS THE
WEST COAST ENERGY BEGINS TO PULL NORTHEAST TOWARD THE GREAT LAKES,
WAVES WILL EJECT FROM THE SYSTEM AND PERIODICALLY CONTRIBUTE TO LIFT
ALONG ANY CONVECTIVELY ENHANCED BOUNDARIES LYING ACROSS THE AREA.
THIS WILL MAKE TIMING OF PRECIPITATION DIFFICULT UNTIL THE MAIN
ENERGY PASSES NORTHWEST OF ILLINOIS ON SUNDAY. WILL HAVE TO
GENERALLY BROADBRUSH GIVEN THE POTENTIAL INSTABILITY (1500-2500
J/KG) IN PLACE. 0-6KM SHEAR IS FORECAST TO REMAIN BELOW 20 KTS
THROUGH SATURDAY EVENING, SO WIDESPREAD SEVERE WEATHER IS NOT
EXPECTED THOUGH GIVEN THE HIGH PRECIPITABLE WATER WOULD NOT BE
SURPRISED TO SEE SOME WET MICROBURST ACTIVITY PRODUCING GUSTY WINDS
AT TIMES SATURDAY.
THE MISSING INGREDIENT (DEEP SHEAR) JOINS THE ENVIRONMENT ON SUNDAY
AS THE MAIN WAVE PASSES NORTHWEST OF ILLINOIS. 0-6KM SHEAR IS
EXPECTED TO SURPASE 40 KTS BY SUNDAY EVENING. THERE DOES SEEM TO BE
POTENTIAL FOR ROTATING UPDRAFTS GIVEN GFS FORECASTED 0-1KM HELECITY
VALUES OF 125-150 M2/S2 AND LCL HEIGHTS BELOW 900 MB. STORM MOTION
ALSO SUGGESTS THAT WINDS MAY BE A THREAT WITH FORECASTED STORM
MOTION AROUND 40 KTS. THREAT WILL LIKELY INCREASE FROM SOUTHEAST TO
NORTHWEST ACROSS FORECAST AREA DUE TO PROXIMITY OF THE WAVE.
ASSOCIATED COLD FRONT IS EXPECTED TO PUSH THROUGH SUNDAY NIGHT AND
MUCH COOLER TEMPERATURES ARE EXPECTED FOR THE BEGINNING OF THE WORK
WEEK. STILL SOME SPREAD IN LATEST MODELS WITH REGARDS TO HOW MUCH
COLD AIR WILL PENETRATE THE MIDWEST BEHIND FRONT WITH THE ECMWF
COOLER THAN GFS/DGEX. HOWEVER, 12Z GFS IS TRENDING TOWARD THIS
COOLER SOLUTION. WILL COMPROMISE BETWEEN THE TWO SOLUTIONS FOR
NOW AND KEEP AT LEAST SOME LOW POPS IN FOR WED THROUGH THU.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1237 PM CDT THU MAY 14 2015
INITIAL BATCH OF SHOWERS HAS BEEN ERODING IN THE DRY AIR OVER
CENTRAL ILLINOIS...BUT STEADIER SHOWERS ARE MOVING NORTHEAST
THROUGH MISSOURI AND SHOULD AFFECT KPIA/KSPI TOWARD MID AFTERNOON.
HAVE NOT MADE MUCH CHANGE TO THE CURRENT TAF SET THROUGH ABOUT
09Z...AS SCATTERED RAIN WILL CONTINUE TO DEVELOP THIS EVENING.
HAVE REMOVED THUNDER MENTION AT KDEC/KCMI AS THE BETTER
INSTABILITY SHOULD BE FURTHER TO THE WEST. STILL HAVE SOME
CONCERNS WITH LLWS POTENTIAL IN THE 03-09Z TIME RANGE...BUT ENOUGH
QUESTIONS REMAIN ON CONVECTIVE POTENTIAL TO HOLD OFF MENTION.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...GEELHART
LONG TERM...BARKER
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1237 PM CDT THU MAY 14 2015
.UPDATE...
ISSUED AT 952 AM CDT THU MAY 14 2015
SHOWERS IN WEST CENTRAL ILLINOIS HAVE BEEN STRUGGLING TO MAKE ANY
EASTWARD PROGRESS. OUR MORNING SOUNDING SHOWED VERY DRY AIR BELOW
15000 FEET...AND CEILINGS UNDERNEATH THE RAIN SHIELD ARE
STRUGGLING TO GET MUCH BELOW 7000 FEET. RAP FORECAST SOUNDINGS
KEEP IT PRETTY DRY BELOW 850 MB INTO THE AFTERNOON AND FOCUS MUCH
OF THE RAIN ALONG AND WEST OF THE ILLINOIS RIVER. THIS WOULD BE
ASSOCIATED WITH THE SHOWERS THAT ARE CURRENTLY STEADILY MOVING
THROUGH CENTRAL AND SOUTHWEST MISSOURI. THE RADAR ECHOES MOVING
OUT OF SOUTHWEST ILLINOIS ARE ALSO VERY LIGHT...AND THESE WILL BE
MOVING INTO THE SOUTHEAST PART OF THE FORECAST AREA SHORTLY AFTER
MIDDAY.
HAVE SENT SOME UPDATED ZONES/GRIDS TO MAINLY REFINE THE RAIN
TRENDS.
&&
.SHORT TERM...(TODAY)
ISSUED AT 319 AM CDT THU MAY 14 2015
1030MB HIGH CENTERED OVER THE EASTERN GREAT LAKES CONTINUES TO
CONTROL THE WEATHER ACROSS CENTRAL ILLINOIS EARLY THIS
MORNING...RESULTING IN COOL/DRY CONDITIONS WITH 07Z/2AM TEMPERATURES
MAINLY IN THE UPPER 40S AND LOWER 50S. AIRMASS IS QUITE DRY...AS
EVIDENCED BY THE 00Z KILX UPPER AIR SOUNDING AND CURRENT SURFACE
DEWPOINTS IN THE LOWER 40S. SHORT-WAVE TROUGH SHOWN ON LATEST WATER
VAPOR IMAGERY OVER KANSAS/OKLAHOMA WILL LIFT NORTHWARD
TODAY...SPREADING CLOUDS AND SHOWERS INTO PORTIONS OF CENTRAL
ILLINOIS. DUE TO THE VERY DRY AIR INITIALLY IN PLACE...THINK MODELS
ARE STILL TOO FAST IN BRINGING THE PRECIP INTO THE AREA. HAVE
THEREFORE SLOWED ITS NORTHEASTWARD SPREAD...WITH LOCATIONS
ALONG/EAST OF A BLOOMINGTON TO EFFINGHAM LINE REMAINING DRY UNTIL
EARLY AFTERNOON AT THE EARLIEST. AREAS ALONG THE INDIANA BORDER
WILL LIKELY STAY DRY FOR THE ENTIRE DAY. FURTHER WEST...RAIN
CHANCES INCREASE TO LIKELY ALONG/NORTHWEST OF THE ILLINOIS RIVER BY
AFTERNOON. DUE TO EXTENSIVE CLOUD COVER AND E/SE WINDS...HAVE GONE
SLIGHTLY BELOW MAV GUIDANCE FOR HIGHS TODAY...WITH READINGS
GENERALLY IN THE MIDDLE TO UPPER 60S...EXCEPT LOWER 70S ALONG/SOUTH
OF I-70 WHERE A FEW PEEKS OF SUNSHINE WILL BE POSSIBLE.
.LONG TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 319 AM CDT THU MAY 14 2015
UPPER WAVE WILL TRACK FROM MINNESOTA/IOWA THIS EVENING INTO THE
GREAT LAKES BY FRIDAY MORNING...KEEPING RAIN CHANCES ALIVE ACROSS
MUCH OF CENTRAL ILLINOIS. HIGHEST POPS WILL BE FOCUSED IN CLOSER
PROXIMITY TO THE STRONGEST FORCING FROM THE PEORIA AND
BLOOMINGTON AREAS NORTHWARD...TAPERING DOWN TO JUST SLIGHT CHANCES
ALONG/SOUTH OF I-70. FORECAST SOUNDINGS ARE INITIALLY QUITE
STABLE...HOWEVER MODEST ELEVATED INSTABILITY DEVELOPS OVERNIGHT
WITH MUCAPE VALUES APPROACHING 1000J/KG. WILL THEREFORE MENTION A
CHANCE OF THUNDER ACROSS THE BOARD TONIGHT.
ONCE THE WAVE EXITS...UPPER HEIGHTS RISE AND OVERALL FORCING FOR
ADDITIONAL CONVECTION WANES FOR BOTH FRIDAY AND SATURDAY. WHILE
WEAK IMPULSES EMBEDDED WITHIN THE BROAD SOUTHWESTERLY UPPER FLOW
PATTERN MAY TRIGGER A FEW SHOWERS AND THUNDERSTORMS FROM TIME TO
TIME...WIDESPREAD PRECIP IS NOT LIKELY. HAVE THEREFORE CONTINUED TO
KEEP POPS IN THE LOW CHANCE CATEGORY THROUGH SATURDAY. MAIN WEATHER
STORY BOTH DAYS WILL BE THE RETURN OF WARM AND HUMID CONDITIONS AS
HIGH TEMPERATURES REACH THE 80S AND DEWPOINTS CLIMB WELL INTO THE
60S.
WESTERN CONUS CLOSED LOW WILL LIFT INTO THE NORTHERN PLAINS ON
SUNDAY...THEN GRADUALLY OPEN AND SHIFT INTO THE NORTHERN GREAT LAKES
BY MONDAY. MODELS CONTINUE TO SPEED UP THIS PROCESS...WITH THE
ASSOCIATED COLD FRONT NOW EXPECTED TO PASS THROUGH CENTRAL ILLINOIS
LATE SUNDAY NIGHT. THE AIRMASS AHEAD OF THE FRONT WILL BECOME
MODERATELY UNSTABLE SUNDAY AFTERNOON/EVENING...WITH SBCAPES RANGING
FROM 1500 TO 2500J/KG. AT THE SAME TIME...0-6KM BULK SHEAR WILL
INCREASE INTO THE 35 TO 40KT RANGE AS UPPER TROUGH APPROACHES.
WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THIS
FAVORABLE ENVIRONMENT WELL AHEAD OF THE COLD FRONT ALONG A
PRE-FRONTAL TROUGH...WITH SOME OF THE STORMS POTENTIALLY BECOMING
SEVERE DURING THE AFTERNOON AND EVENING. WILL CARRY LIKELY POPS
EVERYWHERE DURING THE DAY SUNDAY...THEN WILL BEGIN DECREASING POPS
FROM WEST TO EAST SUNDAY NIGHT. HAVE HUNG ON TO LOW CHANCE POPS
ALONG/SOUTH OF I-70 INTO MONDAY...BUT IF TRENDS CONTINUE THESE
MAY NEED TO BE REMOVED BY LATER SHIFTS.
ONCE FRONT PASSES...STRONG CANADIAN HIGH PRESSURE WILL BRING ANOTHER
CHILLY AIRMASS INTO CENTRAL ILLINOIS NEXT WEEK. MODELS DIFFER ON
EXACTLY HOW COOL IT WILL BE...WITH ECMWF NUMERIC GUIDANCE RUNNING
NEARLY 10 DEGREES COOLER THAN THE MEX. GIVEN STRENGTH OF
APPROACHING HIGH...HAVE UNDERCUT MEX BY A FEW DEGREES BUT HAVE NOT
YET GONE AS COOL AS THE ECMWF WOULD SUGGEST. RESULTING HIGHS WILL
SLIP INTO THE 60S FOR TUESDAY AND WEDNESDAY...WITH OVERNIGHT LOWS
DIPPING INTO THE 40S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1237 PM CDT THU MAY 14 2015
INITIAL BATCH OF SHOWERS HAS BEEN ERODING IN THE DRY AIR OVER
CENTRAL ILLINOIS...BUT STEADIER SHOWERS ARE MOVING NORTHEAST
THROUGH MISSOURI AND SHOULD AFFECT KPIA/KSPI TOWARD MID AFTERNOON.
HAVE NOT MADE MUCH CHANGE TO THE CURRENT TAF SET THROUGH ABOUT
09Z...AS SCATTERED RAIN WILL CONTINUE TO DEVELOP THIS EVENING.
HAVE REMOVED THUNDER MENTION AT KDEC/KCMI AS THE BETTER
INSTABILITY SHOULD BE FURTHER TO THE WEST. STILL HAVE SOME
CONCERNS WITH LLWS POTENTIAL IN THE 03-09Z TIME RANGE...BUT ENOUGH
QUESTIONS REMAIN ON CONVECTIVE POTENTIAL TO HOLD OFF MENTION.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
205 PM EDT THU MAY 14 2015
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 329 AM EDT THU MAY 14 2015
WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO
EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL...
STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF
A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /TODAY/...
ISSUED AT 1013 AM EDT THU MAY 14 2015
ONLY CHANGE TO THE ONGOING FORECAST WAS TO INCREASE CLOUD COVER
BASED ON CURRENT TRENDS AND GUIDANCE. THUS...DECIDED TO LOWER TEMPS A
DEGREE OR TWO ACROSS MOST OF THE FORECAST AREA. PREVIOUS DISCUSSION
FOLLOWS...
ISSUED AT 329 AM EDT THU MAY 14 2015
HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS
MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH
CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM
THE MID 40S TO THE MID 50S.
THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE
DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER
TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE
CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI
VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO
VALLEY AHEAD OF IT.
EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE
DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE
INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE
SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD
LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT
CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT
SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL
CONTINUE WITH A DRY FORECAST TODAY.
TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE
TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS
GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 329 AM EDT THU MAY 14 2015
FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE
PERIOD.
UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A
WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL
LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS
SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES
ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE
OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN
HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH
TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED
BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST
SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED.
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING
ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED
CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST
UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40
POPS OVER THE ENTIRE FORECAST AREA.
REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND
POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO
VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN
ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE
INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP
OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND
LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS
AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND
SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT.
TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB
TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S
MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE
WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
ISSUED AT 205 PM EDT THU MAY 14 2015
ENSEMBLES AND DETERMINISTIC MODELS CONTINUE TO SUGGEST A WARM AND
UNSETTLED START TO THE EXTENDED.
THE DETERMINISTIC 12Z GFS AND 00Z ECMWF ALONG WITH THE ENSEMBLE
MEANS ARE IN VERY GOOD AGREEMENT REGARDING THE SYNOPTIC PATTERN FOR
THE EXTENDED. THEY LIFT AN UPPER LOW...CURRENTLY OFF THE CALIFORNIA
COAST...NORTHEAST TO ONTARIO ON MONDAY. THIS WILL ALLOW A FRONTAL
SYSTEM TO SWEEP SOUTHEAST ACROSS CENTRAL INDIANA ON MONDAY. THE
FRONT WILL INTERACT WITH WARM...MOIST AND UNSTABLE AIR AND TRIGGER
SCATTERED TO NUMEROUS THUNDERSTORMS SUNDAY NIGHT AND MONDAY...BEFORE
COOLER AND DRY WEATHER RETURN UNDER THE INFLUENCE OF STRONG HIGH
PRESSURE BUILDS IN FROM THE WEST. REGIONAL BLEND POPS HANDLE THIS
WELL WITH GOOD CHANCE POPS SUNDAY NIGHT INTO MONDAY AND DRY BY
MONDAY NIGHT. TO WRAP UP THE EXTENDED...A WEAK SOUTHERN SYSTEM COULD
BRING A FEW SHOWERS OR STORMS TO THE AREA BY NEXT THURSDAY.
TEMPERATURES SHOULD START OFF ABOVE NORMAL AHEAD OF THE COLD FRONT
AND THEN FALL TO BELOW NORMAL BEHIND THE FRONT WITH HIGHS ONLY IN
THE 60S LOOKING GOOD BY TUESDAY PER THE REGIONAL BLEND.
&&
.AVIATION /DISCUSSION FOR THE 141800Z TAF ISSUANCE/...
ISSUED AT 1215 PM EDT THU MAY 14 2015
GOOD CONFIDENCE THAT VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY
EXCEPT PERHAPS BRIEF MVFR TOWARD 12Z IN SCATTERED SHOWERS OR
THUNDERSTORMS. SHOULD BE DRY THROUGH AT LEAST 04Z ACROSS THE
TERMINALS...AND CONFIDENCE IS NOT GOOD ON TIMING A TEMPO GROUP THAT
FAR OUT AT ANY ONE AIRPORT...SO WILL JUST TREND TOWARDS INCREASING
AFTERNOON MID DECK AND INCREASING OVERNIGHT CU DECK.
WINDS WILL START OFF SOUTHEAST AND THEN VEER TO SOUTH AND SOUTHWEST
TONIGHT AND FRIDAY. SPEEDS LOOK TO BE 10 KNOTS OR LESS BUT THEN UP
TO 15 KNOTS AFTER 14Z FRIDAY WITH GUSTS TO 20.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...MRD/RYAN
SHORT TERM...RYAN
LONG TERM....MK
AVIATION...MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1215 PM EDT THU MAY 14 2015
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 329 AM EDT THU MAY 14 2015
WARMER AND MORE HUMID WEATHER WILL RETURN BEGINNING FRIDAY INTO
EARLY NEXT WEEK AS A WARM FRONT LIFTS THROUGH THE AREA TONIGHT.
SCATTERED SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AS WELL...
STARTING LATER TONIGHT AND CONTINUING THROUGH MONDAY. THE PASSAGE OF
A COLD FRONT MONDAY WILL USHER IN COOLER AND DRIER CONDITIONS FOR
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /TODAY/...
ISSUED AT 1013 AM EDT THU MAY 14 2015
ONLY CHANGE TO THE ONGOING FORECAST WAS TO INCREASE CLOUD COVER
BASED ON CURRENT TRENDS AND GUIDANCE. THUS...DECIDED TO LOWER TEMPS A
DEGREE OR TWO ACROSS MOST OF THE FORECAST AREA. PREVIOUS DISCUSSION
FOLLOWS...
ISSUED AT 329 AM EDT THU MAY 14 2015
HIGH PRESSURE CENTERED OVER THE EASTERN GREAT LAKES EARLY THIS
MORNING WITH COOL EASTERLY FLOW ACROSS THE FORECAST AREA. HIGH
CLOUDS ALREADY STREAMING INTO THE REGION. 07Z TEMPS RANGED FROM
THE MID 40S TO THE MID 50S.
THE HIGH WILL CONTINUE TO MOVE SOUTHEAST THROUGH THE COURSE OF THE
DAY INTO THE MID ATLANTIC REGION. LOW LEVEL FLOW WILL GRADUALLY VEER
TO A SOUTHEAST DIRECTION FOR MUCH OF THE DAY. UPPER WAVE OVER THE
CENTRAL PLAINS WILL TRACK NORTHEAST INTO THE UPPER MISSISSIPPI
VALLEY BY THIS EVENING...WITH MOISTURE ADVECTING INTO THE OHIO
VALLEY AHEAD OF IT.
EXPECT MID AND HIGH LEVEL CLOUDS TO STEADILY INCREASE THROUGH THE
DAY...WITH MOSTLY CLOUDY SKIES BY LATE AFTERNOON. WHILE MOISTURE
INCREASES ABOVE 10KFT...BOUNDARY LAYER WILL REMAIN DRY WITH THE
SOUTHEAST FLOW IN THE LOW LEVELS. HRRR GUIDANCE TRYING TO SPREAD
LIGHT PRECIP INTO OUR WESTERN COUNTIES THIS AFTERNOON BUT
CONSIDERING THE LACK OF MOISTURE THROUGH THE BOUNDARY LAYER...CANNOT
SEE MORE THAN POSSIBLY A STRAY SPRINKLE PRIOR TO THE EVENING. WILL
CONTINUE WITH A DRY FORECAST TODAY.
TEMPS...CONTINUED WARM ADVECTION AND FILTERED SUNSHINE WILL ENABLE
TEMPS TO WARM INTO THE LOWER 70S MOST AREAS. TRENDED CLOSE TO MAVMOS
GUIDANCE.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
ISSUED AT 329 AM EDT THU MAY 14 2015
FORECAST CHALLENGES ARE ON PRECIP CHANCES AND TEMPS THROUGHOUT THE
PERIOD.
UPPER WAVE WILL TRACK INTO THE GREAT LAKES TONIGHT AND WEAKEN AS A
WARM FRONT LIFTS THROUGH THE AREA. BULK OF THE FORCING ALOFT WILL
LARGELY REMAIN NORTHWEST OF THE FORECAST AREA...BUT LOWER LEVELS
SHOULD CONTINUE TO MOISTEN AS A 35-40KT LOW LEVEL JET NOSES MOVES
ACROSS THE NORTHERN PART OF THE STATE DURING THE LATTER PART OF THE
OVERNIGHT INTO FRIDAY MORNING. WILL CARRY CHANCE POPS OVER NORTHERN
HALF OF THE FORECAST AREA WITH ONLY 20 POPS FURTHER SOUTH
TONIGHT...WITH GREATER FOCUS ON PRECIP AFTER MIDNIGHT. HAVE SCALED
BACK ISOLATED THUNDER TO AREAS ALONG AND NORTH OF I-70 WITH JUST
SHOWERS FURTHER SOUTH AS ELEVATED INSTABILITY REMAINS LIMITED.
SCATTERED PRECIP WILL LINGER THROUGH FRIDAY MORNING BEFORE RIDGING
ALOFT REESTABLISHES. POTENTIAL FOR REDEVELOPMENT OF SCATTERED
CONVECTION ON FRIDAY AFTERNOON WITHIN THE INCREASINGLY MOIST
UNSTABLE AIRMASS ADVECTING INTO CENTRAL INDIANA. WILL MAINTAIN 30-40
POPS OVER THE ENTIRE FORECAST AREA.
REMAINDER OF THE SHORT TERM WILL SEE WARM HUMID CONDITIONS AND
POTENTIAL FOR SCATTERED STORMS AS GULF MOISTURE LIFTS INTO THE OHIO
VALLEY AROUND THE BACK SIDE OF HIGH PRESSURE OVER THE WESTERN
ATLANTIC. CONVECTIVE DEVELOPMENT WILL LARGELY HINGE ON AVAILABLE
INSTABILITY...LOW LEVEL MOISTURE AND SUBTLE WAVES DRIFTING OVERTOP
OF THE RIDGE. CONSIDERING LACK OF EXTENSIVE FORCING ALOFT AND
LIMITED BL SHEAR...THIS DOES NOT WARRANT ANY HIGHER THAN CHANCE POPS
AT THIS POINT IN TIME. WILL CARRY 30-50 POPS FRIDAY NIGHT AND
SATURDAY WITH SLIGHTLY LOWER POPS SATURDAY NIGHT.
TEMPS...BACK TO A SUMMER-LIKE REGIME THROUGH THE PERIOD AS 850MB
TEMPS SURGE TO 14-16C SOUTH OF THE WARM FRONT. GOING LOW TO MID 80S
MOST AREAS FRIDAY AND SATURDAY...GENERALLY AT OR JUST ABOVE THE
WARMER MAVMOS. LOWS WILL JUMP INTO THE MID 60S BY SATURDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
ISSUED AT 329 AM EDT THU MAY 14 2015
ENSEMBLES IN GOOD AGREEMENT IN MOVING AN UPPER TROUGH ACROSS THE
NORTHERN MIDWEST AND WESTERN GREAT LAKES DURING THE SUNDAY/MONDAY
PERIOD...WITH UPPER FLOW BECOMING MORE ZONAL IN THE WAKE OF THIS
SYSTEM TOWARDS THE MIDDLE OF NEXT WEEK.
WILL KEEP POPS IN THE FORECAST FOR SUNDAY AND MONDAY AS THE UPPER
SYSTEM AND ASSOCIATED COLD FRONT MOVE THROUGH THE AREA. ENSEMBLES
INDICATE LITTLE POTENTIAL FOR PRECIPITATION IN THE WAKE OF THIS
SYSTEM ON TUESDAY AND WEDNESDAY...SO WILL CONTINUE WITH A DRY
FORECAST AFTER MONDAY.
&&
.AVIATION /DISCUSSION FOR THE 141800Z TAF ISSUANCE/...
ISSUED AT 1215 PM EDT THU MAY 14 2015
GOOD CONFIDENCE THAT VFR CONDITIONS WILL CONTINUE THROUGH FRIDAY
EXCEPT PERHAPS BRIEF MVFR TOWARD 12Z IN SCATTERED SHOWERS OR
THUNDERSTORMS. SHOULD BE DRY THROUGH AT LEAST 04Z ACROSS THE
TERMINALS...AND CONFIDENCE IS NOT GOOD ON TIMING A TEMPO GROUP THAT
FAR OUT AT ANY ONE AIRPORT...SO WILL JUST TREND TOWARDS INCREASING
AFTERNOON MID DECK AND INCREASING OVERNIGHT CU DECK.
WINDS WILL START OFF SOUTHEAST AND THEN VEER TO SOUTH AND SOUTHWEST
TONIGHT AND FRIDAY. SPEEDS LOOK TO BE 10 KNOTS OR LESS BUT THEN UP
TO 15 KNOTS AFTER 14Z FRIDAY WITH GUSTS TO 20.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...MRD/RYAN
SHORT TERM...RYAN
LONG TERM....JAS
AVIATION...MK
VISIT US AT HTTP://WWW.WEATHER.GOV/IND
FOLLOW US ON FACEBOOK...TWITTER AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSINDIANAPOLIS
WWW.YOUTUBE.COM/NWSINDIANAPOLIS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1248 PM CDT THU MAY 14 2015
.SYNOPSIS...
ISSUED AT 312 AM CDT THU MAY 14 2015
AS OF 2 AM...THE DRY AIRMASS OVER FAR EASTERN
MO...EASTERN IOWA AND ILLINOIS HAS HELD ITS GROUND AS THE LARGE
PLUME OF MOISTURE ADVECTION HEADS MAINLY NORTHWARD OVER THE WESTERN
2/3RDS OF IOWA AND THE MISSOURI RIVER VALLEY. THUS...WE HAVE
SITUATION WHERE LOCATIONS ARE SEEING VERY SLOW PROGRESS EAST OF THE
WIDESPREAD RAIN. WITH LOW LEVEL THROUGH 850MB WINDS REMAINING FROM
THE EAST TO SOUTHEAST THROUGH EARLY MORNING...THIS SLOW PROGRESSION
SHOULD CONTINUE TO BE SEEN.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 312 AM CDT THU MAY 14 2015
TODAY AND TONIGHT... MODEL GUIDANCE ALL BRINGS THE
MOISTURE ADVECTION INTO THE HEART OF THE CWA DURING THE DAY
TODAY...WITH THE TIMING THE MAIN DIFFERENCES. THE ECMWF AND GFS ARE
BOTH QUICKER IN VEERING WINDS AT 850MB AROUND COMPARED TO THE SLOWER
NAM. MESOSCALE MODELS ARE A BIT SPLIT...WITH THE HRRR AND RAP
AGGRESSIVE IN VEERING MOISTURE INTO THE AREA...WHILE THE ARW AND NMM
ARE SLOWER...AND MUCH CLOSER TO THE NAM DEPICTION. THIS DIFFERENCE
IS MAKING A CHALLENGING CALL..SINCE ALL ARE INITIALIZING RATHER
WELL WITH MEASURABLE RAINS IN IOWA MAINLY WEST OF I-35 THROUGH 06Z.
HOWEVER...LOOKING AT OUR RADAR...THERE ARE ALREADY SHOWERS AT LEAST
ALOFT...IF NOT HITTING THE GROUND AS FAR EAST AS A VINTON TO KEOKUK
LINE. THAT SUPPORTS MOISTURE TRANSPORT BEING WELL EAST OF THE MORE
CONSERVATIVE SOLUTIONS...AND WILL PLAY A POP FORECAST MORE CLOSELY
TO THE ECMWF TODAY. EXPECT CLOUDY SKIES THROUGHOUT...WITH LITTLE
HEATING WEST ALL DAY...WHILE EAST HAS A DRY MORNING...AND MODEST
TEMPERATURE RECOVERY TO THE MID 60S. WILL SPREAD CATEGORICAL POPS
EAST TO AROUND MANCHESTER TO BURLINGTON BY MID MORNING...THEN SHIFT
LIKELY POPS EAST OVER THE REST OF THE CWA THIS AFTERNOON. THIS MAY
NEED A CATEGORICAL SHIFT UPWARDS AS WELL...BUT WILL GIVE A 10
PERCENT NOD TO THE SLOWER SOLUTIONS HERE...AND KEEP IT LIKELY.
TONIGHT...THE GLOBAL MODELS STRONGLY SUGGEST AN UPTICK IN CONVECTIVE
POTENTIAL OVER THE NORTHERN 2/3RDS OF THE CWA THIS EVENING. IN
FACT...THEY SUGGEST A WEAK MCS OF SORTS...BUT THE NAM AND OTHER
MESOMODELS SUGGEST THIS ACTIVITY FARTHER SOUTH. I AM DOUBTFUL OF
BUILDING ANY SURFACE BASED CAPE ANYWHERE IN ILLINOIS TODAY...SO THE
NORTHERN SOLUTIONS ARE MORE LIKELY SINCE THE VORTICITY CENTER
PASSING OVER THAT REGION SHOULD SUPPORT AN EVENING ROUND OF LIFT.
MUCAPE SHOULD BE LIMITED TO THE SOUTH HALF AND ONLY BE 500 TO 700
PER THE GFS SOLUTIONS...THUS WILL KEEP THUNDER LIMITED TO THAT
PORTION OF THE AREA TONIGHT. BY 06Z...ALL MODELS SHOW THE LLJ
VEERING EAST...WITH THE VORT PASSING INTO WISCONSIN BY THEN...THUS
COVERAGE SHOULD BECOME FAR MORE ISOLATED AFTER THAT TIME. LOWS
TONIGHT...WITH MUCH HIGHER DEWPOINTS IN PLACE THAN THIS
MORNING...WILL MAINLY BE IN THE MID 50S NORTH TO AROUND 60 SOUTH.
ERVIN
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 312 AM CDT THU MAY 14 2015
FRIDAY...UPPER-LEVEL WINDS WILL BE VERY LIGHT AS RIDGING BUILDS IN
BEHIND A SHORTWAVE OVER THE UPPER GREAT LAKES AND AHEAD OF A
LONGWAVE TROUGH AND CLOSED UPPER LOW OVER THE WESTERN U.S.
THE MOST NOTICEABLE SENSIBLE WEATHER ON FRIDAY WILL BE AN
INCREASINGLY HUMID AIRMASS AS SFC DEWPOINTS RISE INTO THE 60S
THANKS TO S/SW WINDS. THE MOIST ATMOSPHERE COUPLED WITH HIGHS IN
THE MID 70S TO LOWER 80S WILL YIELD MUCH GREATER INSTABILITY
COMPARED TO THE PAST SEVERAL DAYS. MUCAPE VALUES OF 1500-2500
J/KG ARE LIKELY. THEREFORE ANY STORM THAT FORMS COULD BE BRIEFLY
STRONG OR SEVERE...ALTHOUGH LACK OF SUFFICIENT VERTICAL SPEED
SHEAR WOULD INHIBIT ANYTHING PROLONGED OR WIDESPREAD.
CONVECTIVE COVERAGE...IT LOOKS ISOLATED TO SCATTERED AT BEST.
THERE DOES NOT LOOK TO BE MUCH IN THE WAY OF FORCING FOR ASCENT
DURING THE DAY AND FORECAST SOUNDINGS DO HAVE A LITTLE SBCIN.
HOWEVER...THE MODELS ARE SHOWING AN UPTICK IN COVERAGE FRIDAY
NIGHT WHEN A SUBTLE 500MB VORTICITY EMBEDDED IN THE SW MID-LEVEL
FLOW MAY TRAVERSE E IOWA/W ILLINOIS. ADDITIONALLY...SOME WEAK
850MB CONVERGENCE IS FORECAST ON THE NOSE OF A SLIGHTLY STRONGER
WIND FIELD OVER SOUTH-CENTRAL IOWA INTO NW MISSOURI.
SATURDAY...HUMID WEATHER CONTINUES ALONG WITH A SCATTERED
THUNDERSTORM THREAT. NEGLIGIBLE FORCING FOR ASCENT...BUT DAYTIME
HEATING MAY BE ENOUGH TO SET OFF SCATTERED SHOWERS AND
STORMS...ESPECIALLY DURING THE AFTN/EVENING. CONDITIONAL
INSTABILITY IS FORECAST TO BE NEAR OR SLIGHTLY HIGHER THAN ON
FRIDAY. 0-6 KM BULK SHEAR MAY PEAK NEAR 30 KTS SO A LITTLE HIGHER
THAN FRIDAY AS WELL.
SPC HAS OUTLOOKED THE EXTREME WESTERN PORTION OF THE DVN
CWA IN A SLIGHT RISK FOR SEVERE THUNDERSTORMS. STORMS THAT FORM
IN THIS ENVIRONMENT HAVE THE POTENTIAL TO PRODUCE HAIL AND WIND
GUSTS AT SEVERE LEVELS BUT IF ANYTHING DOES OCCUR IT WILL BE
ISOLATED.
FOR FRIDAY AND SATURDAY ANY STORMS THAT FORM WILL MOVE
SLOWLY...GENERALLY FROM SW TO NE AT LESS THAN 30 MPH...AND POSE A
THREAT FOR LOCALIZED HEAVY RAINFALL VIA FORECAST STORM MOTION
VECTORS AND PWAT VALUES NEAR 1.50 INCHES.
SUNDAY...THERE IS A RISK FOR STRONG AND SEVERE STORMS ACROSS THE
FORECAST AREA. MODEL GUIDANCE IS SHOWING OVERLAP OF HIGHER
INSTABILITY AND SHEAR IN ADVANCE OF AN APPROACHING COLD FRONT. RIGHT
NOW BEST SYNOPTIC DYNAMICS PASS OVER WESTERN IOWA INTO MINNESOTA AS
DOES THE SFC LOW...SO STORM COVERAGE ACROSS THE DVN CWA MAY NOT BE
THAT WIDESPREAD AND MAY BE MOSTLY ANCHORED TO THE VICINITY OF THE
SFC COLD FRONT.
MONDAY THROUGH WEDNESDAY...BOTH THE GFS AND ECMWF ADVECT A MUCH
DRIER AIRMASS INTO THE UPPER MIDWEST AS A SPRAWLING HIGH PRESSURE
SYSTEM DROPS OUT OF CANADA INTO THE NORTHERN U.S. THREAT FOR
MEASURABLE RAIN IS QUITE LOW AT THIS POINT SO SHOULD BE A PLEASANT
PERIOD WITH HIGHS IN THE 60S AND LOWS IN THE 40S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1235 PM CDT THU MAY 14 2015
VFR CIGS WILL BE ERODING FROM THE SOUTHWEST AS RAIN AND SATURATION
PROCESSES MOVE INTO THE TAF SITES. MORE SUBSTANTIAL RAIN MAY STILL
NOT GET INTO THE DBQ VCNTY UNTIL LATE AFTERNOON. HEAVIER SHOWERS WITH
SOME EMBEDDED THUNDER NOW IN CENTRAL TO NORTHEASTERN MO WILL
IMPACT THE BRL TO MLI SITES AFTER 2 PM AND INTO THE EVENING WITH
MVFR CIGS AND VSBYS. AREAS OF RAIN THEN TO PERSIST THROUGH LATE
EVENING/10 PM CDT...BEFORE DIMINISHING. THEN AS A WEAK BOUNDARY
MOVES ACRS THE AREA...SFC WINDS MAY GO LIGHTER SOUTH TO SOUTHWEST
LATE TONIGHT. WITH MORE LLVL MOISTURE BEING ADVECTED UP ACRS THE
REGION...THESE LIGHTER WINDS MAY ALLOW FOR IFR CIGS AND VSBYS FROM
FOG TO FORM AFTER MIDNIGHT AND INTO EARLY FRI MORNING AT ALL TAF
SITES EXCEPT MAYBE FOR DBQ. A LOW CHC FOR MORE SCTRD SHOWERS/
THUNDERSTORMS TO FESTER ALONG AND SOUTH OF THE BRL SITE LATE
TONIGHT. LIGHT SOUTHEAST TO SOUTHWEST WINDS FRI MORNING MAY NOT
INCREASE/MIX ENOUGH TO HELP VSBYS AND CIGS IMPROVE UNTIL AFTER
15Z. ..12..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...ERVIN
SHORT TERM...ERVIN
LONG TERM...UTTECH
AVIATION...12
AREA FORECAST DISCUSSION
NWS PADUCAH KY
316 PM CDT THU MAY 14 2015
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 254 PM CDT THU MAY 14 2015
ALTHOUGH MID-LEVEL REGION OF THE RIDGE WEAKENED FURTHER EAST THAN
ANTICIPATED IN THE WAKE OF THE EJECTING SHORTWAVE TROUGH TO THE
NORTH AND NORTHEAST...SUBSIDENCE SHOULD BUILD BACK IN THIS
EVENING WITH A SMALLER AMPLITUDE RIDGE ALOFT. THIS SUBSIDENCE WILL
BE SHORT LIVED AS THE NEXT SHORT WAVE ROTATING OUT OF THE ROCKIES
MOVES INTO THE WFO PAH FORECAST AREA BY FRIDAY MORNING. ATTEMPTED
TO DEPICT THE MINIMA ON POPS AND WEATHER IN THE GRIDS THIS
EVENING...FOLLOWED BY A SMALL CHANCE OF RAIN CLOSER TO DAYBREAK
AHEAD OF A WEAK LOW/MID LEVEL TROUGH AXIS EMBEDDED IN A MEAN
SOUTHWEST FLOW ALOFT.
FROM FRIDAY THROUGH SATURDAY NIGHT...A TRAIN OF SMALL AND
TRANSIENT SHORTWAVE IMPULSES WILL WORK THROUGH THE WFO PAH
FORECAST AREA. THE VARIABILITY IS GOING TO MAKE IT DIFFICULT TO GO
MUCH BEYOND CHANCE CATEGORY THROUGH FRIDAY NIGHT. THE INFLUENCE
WILL INITIALLY BE DIURNAL...BUT WEAK FORCING WILL DOMINATE
SATURDAY AND SATURDAY NIGHT IN THE WARM CONVEYOR BELT.
HOWEVER...THE POP SIGNAL GETS MORE PERSISTENT SATURDAY AND
SATURDAY NIGHT OVER EXTREME SOUTHERN ILLINOIS...MOST OF WEST
KENTUCKY AND SOUTHEAST MISSOURI...AS THE MEAN ISENTROPIC LIFT
ZONE REMAINS FOCUSED ACROSS THE AREA FROM SOUTHWEST TO NORTHEAST.
CHANNELED VORTICITY ORIENTED PARALLEL TO THE UPPER FLOW WILL
MAINTAIN INTERMITTENT RAIN ACTIVITY THROUGH THE PERIOD.
LEANED CLOSER TOWARD THE HIGHER RESOLUTION NAM-WRF DETERMINISTIC
AND ENSEMBLE GUIDANCE...INCLUDING THE HRRR IN THE 06-18 HOUR TIME
FRAME...WITH MORE EMPHASIS TOWARD THE ECMWF AND CANADIAN GUIDANCE
TOWARD SATURDAY.
.LONG TERM...(SUNDAY THROUGH THURSDAY)
ISSUED AT 254 PM CDT THU MAY 14 2015
00Z OPS MODELS AND EC/GFS ENSEMBLE MEAN SOLUTIONS REMAINED IN GOOD
AGREEMENT WITH THE OVERALL UPPER AIR PATTERN. AT THE BEGINNING OF
THE PERIOD...A MID LEVEL TROF WILL EJECT NEGATIVE TILT FROM THE
PLAINS INTO THE UPPER MIDWEST SUNDAY. FRONT STILL OFF TO OUR WEST
BUT WITH MOISTURE AND INSTABILITY PRESENT IN AN UNSETTLED SW FLOW
ALOFT...CONTINUED WITH HIGH CHANCE POPS FOR CONVECTION. CONFIDENCE
REMAINS ABOVE AVERAGE.
FRONT WILL SETTLE SOUTH INTO THE AREA LATE SUNDAY NIGHT INTO MONDAY.
LIKELY POPS SUNDAY NIGHT AND ESPECIALLY ACROSS THE SE 2/3 OF THE
CWFA PER THE LATEST OUTPUT. WILL LINGER POPS MONDAY AS THE FRONT
WILL CONTINUE TO PROGRESS SOUTHEAST ACROSS THE AREA. DIMINISHING
POPS MONDAY EVENING...AND IT SHOULD BE DRY AFTER MIDNIGHT MONDAY
NIGHT.
HIGH PRESSURE SHOULD RESULT IN DRY WEATHER TUESDAY THROUGH TUESDAY
NIGHT. THE OVERALL MID LEVEL FLOW PATTERN FLATTENS OUT ACROSS THE
MID CONUS WITH A TROF OFF THE PACIFIC COAST AND OVER SE CANADA. THE
GFS/ECMWF SOLUTIONS OF THE PAST DAY OR SO SUGGEST MODEST MID LEVEL
SUPPORT AND MOISTURE MAY RESULT IN A FEW SHOWERS WEDNESDAY. THURSDAY
IS MORE UNCLEAR. THE MODELS SHOW DECREASING MOISTURE WITH HIGH
PRESSURE TRYING ONCE AGAIN TO BUILD SOUTHEAST. SO NO POPS FOR NOW
THURSDAY.
THE NEW ECMWF GUIDANCE TRENDED A BIT COOLER FOR MONDAY THROUGH
WEDNESDAY. OTHERWISE A CONSENSUS OF THE GFS/GFS ENSEMBLE MOS AND
PREVIOUS ECMWF NUMBERS WERE STEADY. WILL CONTINUE TO MONITOR THIS
TREND. FOR NOW...JUST SLIGHT ADJUSTMENTS TO OUR EXISTING NUMBERS AND
THE OVERALL MOS CONSENSUS FROM THE PAST 48 HOURS.
&&
.AVIATION...
ISSUED AT 1208 PM CDT THU MAY 14 2015
VERY LIGHT RAIN SHOWERS/SPRINKLES STILL MOVING SLOWLY EAST ACROSS
THE AREA...SOME OF WHICH IS NOT HITTING THE GROUND. NOT PLANNING
ON MENTION IN THE TAFS. OTHERWISE MAINLY HIGH CLOUDS WITH A FEW
MID CLOUDS. VFR CONDITIONS THE RULE. LIGHT ESE WINDS WILL
GRADUALLY VEER THROUGH 18Z FRIDAY...LIGHT THROUGH TONIGHT THEN SSW
UP TO 10 KTS BY LATE MORNING FRIDAY.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...SMITH
LONG TERM...CN
AVIATION...CN
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1253 PM CDT THU MAY 14 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 326 AM CDT THU MAY 14 2015
TODAY AND TONIGHT...TIMING TOOLS AND THE HRRR MODEL SHOW THE RAIN
SHIELD ROTATING NORTHEAST AT 15 MPH THIS MORNING SUGGESTING AN EXIT
TIME AROUND 15Z. SATELLITE SHOWS TRAPPED BOUNDARY LAYER MOISTURE
PRODUCING LOW STRATUS WHICH WILL SLOWLY ERODE THIS MORNING AS WEST
AND NORTHWEST WINDS INCREASE TO 10 MPH AFTER SUNRISE. THE
TEMPERATURE FORECAST FOLLOWS THE UPPER EDGE OF THE MODEL ENVELOP FOR
HIGHS IN THE 70S TO 80 SOUTH.
WEAK HIGH PRESSURE WILL BUILD INTO THE FCST AREA THIS AFTERNOON WITH
A FRONT SETTING UP ACROSS SRN NEB BY LATE THIS AFTN. THE NAM
SUGGESTS A LEAD DISTURBANCE OVER AZ THIS MORNING WILL MOVE THROUGH
THE ROCKIES TODAY AND LIFT THE FRONT NORTH TO NEAR THE NORTH PLATTE
VALLEY TONIGHT. MODEST WARM AIR ADVECTION FROM 850MB ON UP HELPS TO
LIFT THE FRONT NORTH BUT ALSO DESTABILIZES THE ATMOSPHERE PRODUCING
SCATTERED TSTMS FROM 06Z ONWARD.
INSTABILITY PROFILES IN THE NAM INDICATE AROUND 1500 J/KG OF CAPE
COMPUTED AT 800 MB AND 3000 J/KG AT 850 MB. THE DRIER GFS SHOWS VERY
LITTLE INSTABILITY AT THESE LEVELS. THE SREF SUPPORTS THE NAM SOLN
DRIVING PWAT TO AN INCH OVERNIGHT. LAPSE RATES ARE STEEP IN BOTH THE
GFS AND NAM BUT THE BULK SHEAR IS WEAK WITH LINEAR WIND FIELDS. THIS
WOULD SUGGEST THE POTENTIAL FOR PULSE TSTM BEHAVIOR WITH
HAIL...POSSIBLY BRIEFLY LARGE. POPS ARE SET AT 40 PERCENT TONIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 326 AM CDT THU MAY 14 2015
LITTLE HAS CHANGED OVER THE LAST 24 HOURS IN THE LONG RANGE.
DETERMINISTIC MODELS AND ENSEMBLE MEANS REMAIN IN SOUND AGREEMENT
WITH THE EVOLUTION OF THE UPPER LEVEL SYNOPTIC PATTERN THROUGH THE
MIDDLE OF NEXT WEEK. FORECASTER CONFIDENCE IS HIGH FOR THE PROLONGED
CONTINUATION OF AN ACTIVE PATTERN OVER THE CENTRAL PLAINS WITH
PERIODIC CHANCES FOR SHOWERS AND THUNDERSTORMS.
LEAD SHORTWAVE EJECTS NORTHEAST INTO THE CENTRAL PLAINS FRIDAY
SETTING THE STAGE FOR POTENTIAL SEVERE WEATHER IN THE SANDHILLS
REGION. A 60KT UPPER LEVEL JET NOSES INTO THE CWA AS A LEE SIDE AREA
OF LOW PRESSURE DEEPENS OVER NORTHEAST COLORADO...WITH A SHARPENING
DRYLINE FROM SW NEBRASKA INTO WESTERN KS. A POLEWARD ADVANCING WARM
FRONT WILL ALSO STRETCH EAST ACROSS THE CWA...HOWEVER THE EXACT
PLACEMENT STILL REMAINS IN QUESTION. THUNDERSTORM INITIATION IS
EXPECTED BY MID TO LATE AFTERNOON IN A ZONE OF POOLING RICH THETA-E
AIR AND INCREASING INSTABILITY BETWEEN THE NORTHEAST SURGING DRYLINE
AND THE WARM FRONT. STRONG DEEP LAYER SHEAR IN EXCESS OF 40 KTS AND
STEEPENING MID-LEVEL LAPSE RATES WILL FOSTER AN ENVIRONMENT
FAVORABLE FOR THE DEVELOPMENT OF SUPERCELL THUNDERSTORMS CAPABLE OF
PRODUCING LARGE HAIL AND DAMAGING WINDS. TORNADO THREAT INCREASES
LATE IN THE DAY IN CONCERT WITH A STRENGTHENING LOW LEVEL
JET...WHICH WILL CREATE MORE FAVORABLE LOW LEVEL SHEAR PROFILES AND
ELONGATED HODOGRAPHS IN THE VICINITY OF THE WARM FRONT AND WESTWARD
TOWARD THE TRIPLE POINT IN THE EASTERN NEBRASKA PANHANDLE. SEVERAL
UNCERTAINTIES STILL REMAIN WITH THE SEVERE WEATHER SETUP FOR
FRIDAY...PRIMARILY DUE TO MODEL DIFFERENCES WITH THE POSITION OF THE
AFOREMENTIONED WARM FRONT. SCATTERED CONVECTION WILL BE ONGOING
FRIDAY MORNING IN A ZONE ISENTROPIC ASCENT ALONG AND NORTH OF THE
WARM FRONT AS IT MOVES NORTHWARD OUT OF KANSAS. MODELS ARE
STRUGGLING WITH THEIR PROGRESSION OF THE FRONT DUE TO DIFFERENCES IN
THEIR CONVECTIVE OUTPUT. ALSO OF CONCERN IS THE LACK OF CONVECTIVE
INHIBITION INDICATED IN MODEL FORECAST SOUNDINGS. A WEAK CAP FAVORS
AN EARLIER ONSET TO CONVECTION AND LIMITS THE DEGREE OF
DESTABILIZATION IN THE WARM SECTOR PRIOR TO STORM INITIATION.
THUNDERSTORM ACTIVITY PUSHES NORTHEAST ALONG THE NOSE OF A VEERING
LLJ FRIDAY NIGHT. A LARGE UPPER LEVEL LOW OVER THE DESERT SOUTHWEST
KICKS NORTHEAST INTO THE CENTRAL PLAINS SATURDAY AND THE ATMOSPHERE
OVER THE CWA RELOADS WITH ANOTHER ROUND OF SEVERE WEATHER POSSIBLE.
MODEL CONSENSUS HAS TRENDED A BIT FURTHER WEST WITH THE WEDNESDAY
EVENING RUNS. THE LEE SIDE AREA OF LOW PRESSURE FROM FRIDAY
RETROGRADES BACK WESTWARD...WITH A SFC TROUGH AXIS STRETCHING FROM
THE KS/CO BORDER NORTHWARD INTO WESTERN NEBRASKA. THUNDERSTORM
INITIATION IS LIKELY ONCE AGAIN DURING THE AFTERNOON HOURS ALONG AND
AHEAD OF THE SFC TROUGH AS STRONG UPPER LEVEL LIFT OVERSPREADS THE
INCREASINGLY UNSTABLE WARM SECTOR. WIND PROFILES LOOK FAIRLY
UNIDIRECTIONAL THROUGH A DEEP LAYER SATURDAY...SO THUNDERSTORMS WILL
LIKELY EXPERIENCE UPSCALE GROWTH WITH LARGE HAIL...DAMAGING
WINDS...AND LOCALLY HEAVY RAINFALL THE PRIMARY THREATS AS THEY TRACK
NORTH AND EAST THROUGH THE EVENING.
A TRANSITORY RIDGE MOVES OVER THE CENTRAL PLAINS EARLY IN THE WEEK
BRINGING A TEMPORARY PERIOD OF DRIER CONDITIONS. PRECIPITATION
CHANCES RAMP UP AGAIN BY TUESDAY AS ANOTHER UPPER LEVEL LOW MOVES
ONSHORE FROM THE PACIFIC AND INTO THE WESTERN CONUS. RAINFALL
CHANCES INCREASE AS A PLUME OF SUBTROPICAL MOISTURE ALOFT SURGES
NORTHEAST OUT OF THE BAJA REGION...WHILE NORTHWARD MOISTURE
TRANSPORT IN THE LOWER LEVELS LIFTS UP AND OVER THE WARM FRONT
SITUATED JUST SOUTH OF THE CWA. CROSS SECTION ANALYSIS OF THE GFS
AND EC SHOW STRONG AND PERSISTENT ISENTROPIC LIFT A OVER THE
CWA...ESPECIALLY TUESDAY NIGHT. EVEN THOUGH IT IS IN THE DAY 6-7
RANGE...STUCK WITH LIKELY POPS GIVEN THE HIGHLY FAVORABLE SETUP FOR
WIDESPREAD QPF AND STRONG MODEL CONSENSUS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1250 PM CDT THU MAY 14 2015
VFR CONDITIONS EXPECTED FOR THE AFTERNOON...ALTHOUGH CAN NOT RULE
OUT A BRIEF MVFR CIG ACROSS NRN NEB EARLY.
OVERNIGHT A DISTURBANCE WILL LIFT NORTHEAST ACROSS THE AREA...WITH
A BAND OF THUNDERSTORMS EXPECTED. IMPACT TO SW NEB AFTER
MIDNIGHT...THEN MOVING NORTHEAST THROUGH EARLY MORNING. THE
THUNDERSTORMS WILL LIKELY BRING MVFR OR IFR CIGS THAT COULD LINGER
AFTER THE THUNDERSTORMS LIFT INTO S DAKOTA.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CDC
LONG TERM...MARTIN
AVIATION...MASEK
AREA FORECAST DISCUSSION
NWS HASTINGS NE
732 AM CDT THU MAY 14 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 359 AM CDT THU MAY 14 2015
ALTHOUGH THESE FIRST 24 HOURS CERTAINLY DO NOT FEATURE THE
POTENTIALLY "HIGHER IMPACT" THREAT OF SEVERE THUNDERSTORMS FOR
FRIDAY-SATURDAY AS DESCRIBED IN THE LONG TERM SECTION
BELOW...TODAY AND TONIGHT COME WITH THEIR OWN SET OF
CHALLENGES...NAMELY: 1) TIMING THE END OF RAIN/DRIZZLE THIS
MORNING...2) TIMING HOW QUICKLY/SLOWLY WIDESPREAD CLOUDS DEPART
FROM WEST-EAST TODAY AND RESULTANT IMPACT ON HIGH TEMPS...AND 3)
TRYING TO DETERMINE HOW MUCH THUNDERSTORM DEVELOPMENT/COVERAGE
OCCURS LATE TONIGHT AND WHETHER A FEW OF THESE STORMS COULD
ACTUALLY BE STRONG TO MARGINALLY SEVERE (DESPITE THE LACK OF AN
OFFICIAL SPC MARGINAL RISK AREA ON THE LATEST DAY 1 OUTLOOK).
STARTING OFF WITH THE PRESENT SCENE AS OF 08Z/3AM THIS
MORNING...WE ARE IN THE LATTER STAGES OF A REMARKABLY
BENEFICIAL...LARGELY STRATIFORM (NON-CONVECTIVE/THUNDERSTORM)
WIDESPREAD RAIN EVENT THAT HAS BEEN GOING ON SINCE LATE WED
AFTERNOON/EARLY EVENING. AS OF THIS WRITING...RAIN IS STARTING TO
STEADILY WIND DOWN/BECOME MORE SPOTTY WITHIN THE WESTERN HALF OF
THE CWA...WHILE CONTINUING STEADY IN EASTERN COUNTIES. PER SEVERAL
AUTOMATED AIRPORT GAUGES AND RADAR ESTIMATION...IT APPEARS LIKELY
THAT THE MAJORITY OF THE CWA IS GOING TO END UP WITH A SOLID
0.50-1.00" BEFORE RAIN COMPLETELY ENDS THIS MORNING...CERTAINLY A
WELCOMED EVENT FOR THE MOST PART. THIS LARGE SHIELD OF MAINLY
LIGHT RAIN IS BEING DRIVEN IN THE MID-UPPER LEVELS BY A SLIGHTLY
NEGATIVELY TILTED SHORTWAVE TROUGH CURRENTLY PASSING DIRECTLY
THROUGH THE HEART OF THE CENTRAL PLAINS. WHILE A SMALL ZONE OF
SHORTWAVE RIDGING IS MOVING IN BEHIND THIS WAVE...THE CENTER OF
THE NEXT SIGNIFICANT UPPER LEVEL SYSTEM IS SLOWLY BUT SURELY
APPROACHING THE PACIFIC COAST. AT THE SURFACE EARLY THIS
MORNING...WEAK LOW PRESSURE CENTERED TO THE WEST IS PROMOTING
FAIRLY UNIFORM SOUTHEAST BREEZES GENERALLY 7-13 MPH IN MOST AREAS.
LOW TEMPS APPEAR ON TRACK TO BOTTOM OUT IN THE 51-54 RANGE IN
MOST PLACES.
NOW LOOKING AHEAD FORECAST-WISE...
EARLY THIS MORNING (THROUGH 12Z/7AM): CERTAINLY THE MAIN ISSUE IS
THE CONTINUING GRADUAL DECREASE IN THE COVERAGE OF MEASURABLE
RAIN...AS THE OVERALL AREA OF RAIN SLOWLY ENDS FROM PRIMARILY
WEST-TO-EAST AS INDIVIDUAL RAIN ELEMENTS STREAM FROM SOUTH-TO-
NORTH. WILL OBVIOUSLY BE CARRYING SOME PRETTY HEFTY EARLY MORNING
POPS IN EASTERN ZONES AND MUCH LOWER VALUES FAR WEST.
HOWEVER...GIVEN THE PRESENCE OF WIDESPREAD LOW STRATUS EVEN IN
AREAS WHERE MEASURABLE RAIN IS ENDING...COULD CERTAINLY SEE SOME
MAINLY NON-MEASURABLE LIGHT DRIZZLE SHOW ITS HAND AS WELL...SO
HAVE INCLUDED THIS MENTION IN WESTERN AREAS WHERE THE MEASURABLE
POP IS BELOW 20 PERCENT. WOULD NORMALLY BE A BIT MORE CONCERNED
ABOUT POTENTIALLY IMPACTFUL FOG DEVELOPING IN AREAS WHERE RAIN IS
ENDING...BUT WITH THE WIDESPREAD LOW STRATUS FIRMLY IN PLACE AND
LIGHT-BUT-STEADY BREEZES AM GOING TO HOLD OFF ON A FORMAL FOG
MENTION FOR NOW AND MONITOR TRENDS TO MAKE SURE AUTOMATED SITES DO
NOT START DROPPING BELOW 1 MILE...WHICH WOULD CERTAINLY JUSTIFY A
LAST-MINUTE FOG INCLUSION SHOULD THIS START OCCURRING.
TODAY (7AM-7PM): BY THE TIME 12Z/7AM ROLLS AROUND IN A FEW
HOURS...ANY LINGERING AREAS OF LIGHT MEASURABLE RAIN SHOULD
LARGELY BE CONFINED TO THE EASTERN HALF OF THE CWA...BUT EVEN THIS
SHOULD BE STEADILY PUSHING OUT WITH TIME...LEAVING ONLY A FEW
HOURS OF LIGHT DRIZZLE POTENTIAL IN ITS WAKE. WILL OBVIOUSLY
UPDATE AGAIN BEFORE SUNRISE BASED ON RADAR TRENDS...BUT FOR NOW WILL
CARRY ONLY A FEW HOURS OF LIKELY POPS IN EASTERN ZONES BEFORE
DROPPING DOWN TO ONLY SLIGHT 20 POPS IN EXTREME EASTERN COUNTIES
ALONG HWY 81 BY LATE MORNING (AGAIN THOUGH...SPOTTY DRIZZLE COULD
EXTEND BACK TO THE TRI-CITIES AREA WELL-PAST SUNRISE). ONCE
RAIN/DRIZZLE FINALLY ENDS...THE BIG QUESTION IS HOW QUICKLY/SLOWLY
DO CLOUDS VACATE FROM WEST-TO-EAST...AS THE MID LEVEL SHORTWAVE
TROUGH LIFTS AWAY FROM THE AREA INTO IA/MN...PROVIDING A BRIEF
PERIOD OF SHORTWAVE RIDGING FOR THIS AFTERNOON/EVENING. IF
ANYTHING...HAVE SLIGHTLY SLOWED DOWN THE CLEARING TREND FROM
PREVIOUS FORECAST...BUT AM COUNTING ON LIGHT WESTERLY LOW-LEVEL
FLOW TO GRADUALLY SCOUR OUT LOW STRATUS (OR AT LEAST TURN IT INTO
A SCATTERED COVERAGE) AS THE DAY WEARS ON. THAT BEING SAID...SOME
OF THE LATEST TRENDS IN 900-850MB RELATIVE HUMIDITY ALONG WITH SKY
COVER PROGS FROM THE LATEST HRRR SUGGEST THAT COUNTIES EAST OF
HIGHWAY 281 COULD HANG ONTO CONSIDERABLE CLOUD COVER WELL INTO THE
AFTERNOON WITH ANY APPRECIABLE CLEARING COMING LATE IN THE DAY.
THE BOTTOM LINE IS THAT ALTHOUGH CONFIDENCE IS NOT
OVERLY-HIGH...EXPECT SKY COVER TODAY IN THE WESTERN 1/2 OF THE
CWA TO IMPROVE FROM CLOUDY TO PARTLY CLOUDY/MOSTLY SUNNY...WHILE
THE EASTERN HALF ONLY IMPROVES FROM CLOUDY TO MOSTLY CLOUDY/PARTLY
CLOUDY. OBVIOUSLY THE CLOUD TRENDS WILL HAVE A DECENT IMPLICATION
ON HIGH TEMPERATURES THIS AFTERNOON. ALTHOUGH DID NOT FOLLOW
IT OUTRIGHT...DID TREND HIGHS TOWARD THE LATEST RAP13
NUMBERS...WHICH LOWERED VALUES GENERALLY 3-4 DEGREES IN MOST
CENTRAL/EASTERN COUNTIES...WHILE LEAVING WESTERN ZONES FAIRLY
SIMILAR TO PREVIOUS FORECAST. THE NET RESULT AIMS FROM NEAR-70 FAR
EAST...LOW-MID 70S TRI-CITIES AREA...AND UPPER 70S/LOW 80S FAR
WEST/SOUTHWEST. AS FOR WINDS TODAY...INITIALLY SOUTH/SOUTHEAST
BREEZES THIS MORNING WILL STEADILY BECOME MORE SOUTHWESTERLY IF
NOT WESTERLY AS THE DAY WEARS ON...BUT WITH SUSTAINED SPEEDS NOT
EXPECTED TO AVERAGE MORE THAN 10-15 MPH.
THIS EVENING/TONIGHT (7PM-7AM): IN SHORT...EXPECT A FAIRLY
TRANQUIL EVENING FOLLOWED BY A SOMEWHAT MORE ACTIVE LATE NIGHT
PERIOD WITH POTENTIALLY A FEW STRONG STORMS...ALTHOUGH CONFIDENCE
IS STILL A BIT LOW ON WHETHER THUNDERSTORM DEVELOPMENT WILL BE
MORE ISOLATED OR MORE WIDESPREAD. AS A RESULT...HAVE KEPT ALL
POST-MIDNIGHT POPS CAPPED AT NO HIGHER THAN 30-50 PERCENT FOR
NOW...AND WITH THE HIGHEST VALUES LARGELY FOCUSED OVER THE WESTERN
1/2 OF THE CWA. LOOKING ALOFT TO THE MID-UPPER LEVELS...A BRIEF
PERIOD OF SHORTWAVE RIDGING THIS EVENING WILL QUICKLY GIVE WAY TO
A LOW AMPLITUDE DISTURBANCE MOVING INTO THE CENTRAL PLAINS IN
SOUTHWEST FLOW ALOFT...ALONG THE VERY LEADING EASTERN EDGE OF THE
MAIN WESTERN CONUS TROUGH. ALTHOUGH THERE ARE THE TYPICAL VARIOUS
DEPICTIONS OF HOW CONVECTION WILL PLAY OUT TONIGHT AMONGST THE
VARIOUS DETERMINISTIC AND HIGHER-RES MODELS...GENERALLY TEND TO
PREFER THE DEPICTION OF THE 00Z NSSL 4KM-WRF AT THIS TIME. THIS
MEANS REASONABLY HIGH CONFIDENCE IN A DRY EVENING (PRE-
MIDNIGHT)...ALTHOUGH CONVECTION COULD ALREADY BE APPROACHING THE
CWA FROM SOUTHWEST NEB/SOUTHWEST KS AS IT FIRES UP ALONG THE NOSE
OF AN INCREASING 30-40KT LOW LEVEL JET EVIDENT AT 850MB. THEN
POST-MIDNIGHT...EXPECT ISOLATED TO SCATTERED SHOWERS/STORMS TO
MOVE INTO AND/OR DEVELOP DIRECTLY OVER THE CWA AS THE MID LEVEL
WAVE AND ASSOCIATED LOW LEVEL JET FORCING SPREADS FARTHER EAST.
COULD SEE A MORE CONCENTRATED ZONE OF CONVECTION THAT COULD
EVENTUALLY NECESSITATE LIKELY POPS...BUT JUST TOO TOUGH TO TELL
WHERE EXACTLY THIS WOULD BE YET. THAT BEING SAID...ALTHOUGH STORMS
WILL BE POSSIBLE ALMOST ANYWHERE BETWEEN MIDNIGHT-SUNRISE...THE
WESTERN HALF OF THE CWA SHOULD BE MOST FAVORED. AS FOR STORM
INTENSITY...THAT WILL OBVIOUSLY DEPEND HEAVILY ON THE DEGREE OF
ELEVATED INSTABILITY. AS IS COMMON...THE LATEST 06Z NAM SEEMS A
BIT HIGH WITH 850-700MB LAYER CAPE POTENTIALLY EXCEEDING 2500
J/KG...WHILE THE GFS LOOKS A BIT MORE REALISTIC BUT STILL HAS
ELEVATED CAPE INCREASING TO AROUND 1000 J/KG. ALTHOUGH DEEP LAYER
SHEAR IS PROGGED TO REMAIN FAIRLY WEAK AT ONLY AROUND 20-25KT AT
MOST...THIS INSTABILITY (ESPECIALLY IF THE NAM IS REMOTELY
CORRECT) COULD EASILY SUPPORT A FEW STRONG TO MARGINALLY SEVERE
HAIL CORES AT LEAST IN THE NICKEL-QUARTER RANGE. IN ORDER TO
REMAIN REASONABLY CONSISTENT WITH THE LACK OF AN OFFICIAL MARGINAL
RISK AREA ON THE INITIAL SPC DAY 1 OUTLOOK...WILL KEEP A FORMAL
SEVERE STORM MENTION OUT OF THE HAZARDOUS WEATHER OUTLOOK FOR
NOW...BUT WILL INTRODUCE A MENTION OF LATE-NIGHT STRONG STORM
POTENTIAL TO GET THE BALL TRENDING THAT DIRECTION. TURNING TO
OTHER ELEMENTS...BREEZES TONIGHT SHOULD GENERALLY AVERAGE 5-10 MPH
FROM THE SOUTHEAST AS A WEAK COLD FRONT STALLS OUT JUST NORTH OF
THE CWA THIS EVENING AND LOW PRESSURE DEVELOPS WEST. MADE VERY
LITTLE CHANGE TO LOW TEMPS...AIMING MOST OF THE CWA BETWEEN 57-61
DEGREES. ON ONE LAST NOTE...THE PRESENCE OF FAIRLY LIGHT SOUTHEAST
BREEZES LATE TONIGHT...AND FAIRLY CLOSE SURFACE TEMP/DEWPOINT
DEPRESSIONS ARGUE THAT FOG COULD POSSIBLY BECOME AN ISSUE IN SOME
AREAS...AND THIS HAS MODEST SUPPORT IN THE LATEST SREF VISIBILITY
PROGS. HOWEVER...GIVEN THAT CONFIDENCE IN IMPACTFUL FOG (GENERALLY
1 MILE VISIBILITY OR LESS) ISN/T EVEN THAT HIGH FOR THIS
MORNING...IT/S HARD TO PUT MUCH FAITH IN TRENDS FOR 24 HOURS FROM
NOW...SO WILL KEEP IT OUT OF THE FORECAST FOR NOW AND LET THE
FOCUS REMAIN ON THE THUNDERSTORM CHANCES.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 420 AM CDT THU MAY 14 2015
A FAIRLY ACTIVE WEATHER PATTERN IS EXPECTED THROUGH THE EXTENDED
PERIODS WITH SEVERAL CHANCES FOR SHOWERS AND THUNDERSTORMS AS THE
LOCAL AREA WILL BE INFLUENCED BY MULTIPLE UPPER LEVEL DISTURBANCES
TRACKING OUT OF THE DESERT SOUTHWEST AND INTO THE PLAINS.
OVERALL...TEMPERATURES WILL BE VERY MILD TO START THE
PERIOD...WITH A COLD FRONT DROPPING DOWN ACROSS THE LOCAL AREA
SUNDAY NIGHT/MONDAY...WHICH WILL RESULT IN TEMPERATURES DIPPING
BELOW NORMAL FOR THE FIRST HALF OF NEXT WEEK.
STARTING OFF FRIDAY MORNING...THE LOCAL AREA WILL LIKELY HAVE
ONGOING CONVECTION AS THE LLJ WILL BE POINTED TOWARDS THE LOCAL
AREA AND AN UPPER LEVEL DISTURBANCE IN SOUTHERLY FLOW ADVECTS
ACROSS THE LOCAL AREA. AS THIS CONVECTION TRACKS NORTH THROUGH THE
MORNING HOURS...THE POTENTIAL FOR REDEVELOPMENT IN THE WARM
SECTOR LOOKS FAVORABLE AS DEWPOINTS ARE FORECAST TO CLIMB TO NEAR
60...WHICH SHOULD HELP INSTABILITY VALUES TO SOAR ACROSS THE LOCAL
AREA. THESE INSTABILITY VALUES...COMBINED WITH AMPLE LOW LEVEL
SHEAR...SHOULD RESULT IN ORGANIZED CONVECTION DEVELOPING BY LATE
AFTERNOON...WITH MOST OF SOUTH CENTRAL NEBRASKA IN THE ENHANCED
RISK FOR SEVERE WEATHER ISSUED BY SPC. IF THUNDERSTORMS DO
DEVELOP...EXPECT THE POTENTIAL FOR LARGE HAIL...DAMAGING WIND
GUSTS AS WELL AS ISOLATED TORNADOES UNDER THIS SCENARIO.
AS THE LONGWAVE TROUGH THEN CROSSES THE ROCKIES ON SATURDAY...
EXPECT MULTIPLE UPPER LEVEL DISTURBANCES ROUNDING THE BASE OF THE
LONGWAVE TROUGH TO HELP TRIGGER ADDITIONAL CONVECTION ACROSS THE
LOCAL AREA. ONCE AGAIN...WITH ELEVATED DEWPOINTS ALONG WITH GOOD
CAPE VALUES AND MODEST SHEAR...EXPECT THE POTENTIAL FOR SEVERE
THUNDERSTORMS TO ONCE AGAIN BE POSSIBLE SATURDAY
AFTERNOON/EVENING...WITH JUST ABOUT THE ENTIRE FORECAST AREA NOW
HIGHLIGHTED FOR AN ENHANCED RISK OF SEVERE WEATHER.
CHANCES FOR CONVECTION WILL THEN CONTINUE INTO SUNDAY...WHEN AN
APPROACHING COLD FRONT SHOULD PUT AN END TO THIS MORE SIGNIFICANT
WEATHER...WITH COOLER AND MORE STABLE AIR ANTICIPATED IN ITS WAKE
TO START THE WORK WEEK. WHILE SHORTWAVE RIDGING ALOFT IS ALSO
FAVORED TO START THE WORK WEEK...YET ANOTHER UPPER LEVEL
DISTURBANCE IS FORECAST TO LIFT OUT OF THE SOUTHWEST AS EARLY AS
TUESDAY AFTERNOON...WHICH SHOULD BRING ADDITIONAL CHANCES FOR
SHOWERS AND THUNDERSTORMS ACROSS THE LOCAL AREA. WITH LESS
INSTABILITY TO WORK WITH...EXPECT THUNDERSTORM ACTIVITY FOR MID
WEEK TO BE MORE ISOLATED ACROSS THE REGION.
&&
.AVIATION...(FOR THE 12Z KGRI/KEAR TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 722 AM CDT THU MAY 14 2015
MVFR CONDITIONS ARE EXPECTED AT THE TERMINAL SITES THROUGH THE
BEGINNING HOURS OF THE TAF FOR LOW CEILINGS...HOWEVER...LATER THIS
AFTERNOON CONDITIONS SHOULD IMPROVE TO VFR HAS CLOUD BASES LIFT.
WIND SPEEDS SHOULD ALSO GO LIGHT AND VARIABLE NEAR 00Z...WITH
CONFIDENCE HIGH REGARDING MINIMAL IMPACTS AT THE TERMINALS
WEATHER-WISE THOUGH MOST OF THE AFTERNOON/EVENING. CONFIDENCE
BEGINS TO DECREASE WHEN WE STARTING TALKING ABOUT THUNDERSTORM
POTENTIAL LATE TONIGHT INTO TOMORROW MORNING. CHANCES ARE THERE
COULD BE SOME THUNDERSTORMS IN THE VICINITY OF THE TERMINALS...BUT
CURRENT TRENDS APPEAR TO BE BACKING OFF THIS SCENARIO. THAT BEING
SAID...THUNDERSTORMS ARE EXPECTED AFTER MIDNIGHT ACROSS THE AREA
WITH CHANCES LOOKING TO BE CLOSER TO 12Z...WHICH IS LATER THAN
THE PREVIOUS TAF INITIALLY SUGGESTED. CONFIDENCE IN THUNDERSTORM
DEVELOPMENT AND COVERAGE SHOULD BECOME CLEARER WITH SUBSEQUENT
TAFS.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...PFANNKUCH
LONG TERM...ROSSI
AVIATION...GUERRERO
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
951 AM PDT THU MAY 14 2015
.SYNOPSIS...UNSEASONABLY COOL AND UNSETTLED WEATHER IS EXPECTED
THROUGH SATURDAY AS A PACIFIC STORM SYSTEM IMPACTS THE REGION. RAIN
AND MOUNTAIN SNOW CAN BE EXPECTED AREA WIDE WITH NORTHERN AREAS
FAVORED ON THURSDAY AND SOUTHERN AREAS FAVORED ON FRIDAY. SOME
SCATTERED SHOWERS MAY LINGER ON SATURDAY BEFORE BRIEF IMPROVEMENT
ARRIVES SUNDAY. ANOTHER STORM SYSTEM WILL IMPACT THE REGION EARLY
NEXT WEEK WITH MORE SHOWER AND THUNDERSTORM CHANCES.
&&
.UPDATE...ONLY LINGERING LIGHT SHOWER ACTIVITY LEFT IN THE FAR
NORTHERN LAS VEGAS VALLEY AND THE SHEEP RANGE. MODELS BRING ANOTHER
ROUND OF SHOWERS TO THE VALLEY THIS AFTERNOON INTO THE EVENING
INCLUDING POSSIBLE THUNDERSTORMS.
VISIBLE SATELLITE SHOWS A BROAD DECK OF MID LEVEL CLOUDS OVER SAN
BERNARDINO COUNTY AND MOHAVE COUNTY SPREADING NORTH AND PARTLY TO
MOSTLY CLOUDY CONDITIONS ARE EXPECTED THROUGH THE DAY WHICH WILL
LIKELY LIMIT DAYTIME HEATING IN MOST AREAS. SCATTERED SHOWERS AND
ISOLATED STORMS ARE EXPECTED TODAY AS SHORTWAVE ENERGY AHEAD OF LOW
PRESSURE OFF THE WEST COAST EJECTS INLAND ACROSS THE CWA. -SALMEN-&&
.AVIATION... FOR MCCARRAN...A DENSE BAND OF MID LEVEL CLOUDS ARE
SPREADING ACROSS THE VALLEY AND BKN CLOUDS GENERALLY AOA 15K FEET
ARE EXPECTED BEFORE SHOWERS REDEVELOP THIS AFTERNOON. SOUTH WINDS OF
15-25KT TO CONTINUE WITH GUSTS TO 30KTS POSSIBLE. SOME VARIABILITY
IN WIND SPEED/DIRECTION POSSIBLE WHEN SHOWERS MOVE THROUGH THE
VALLEY LATER THIS AFTERNOON. CIGS IN THE 8-10K FT RANGE THIS IS
EXPECTED LATER THIS AFTERNOON AND EVENING WITH LOW CIGS POSSIBLE IN
RAIN. -SALMEN-
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...WIDESPREAD BKN-OVC CONDITIONS EXPECTED TODAY WITH CLOUD
DECKS LOWERING THROUGH THE DAY. SCT SHOWERS AND THUNDERSTORMS LIKELY
IN NORTHWEST ARIZONA AS WELL AS INYO COUNTY THROUGH MIDDAY...BEFORE
SPREADING INTO THE MOJAVE DESERT THURSDAY AFTERNOON. BEST CHANCES
FOR SHOWERS AND STORMS WILL BE NORTH OF INTERSTATE 40. ADDITIONAL
RAIN EXPECTED FRIDAY ESPECIALLY SOUTH OF A KDAG-KLAS-KSGU LINE.
BREEZY SOUTH WINDS OF 15-20KTS AND GUSTS TO 30KTS EXPECTED.
&&
.PREV UPDATE...809 AM PDT...A QUICK UPDATE TO ADD SHOWERS/STORMS TO
PORTIONS OF CLARK COUNTY INCLUDING THE LV VALLEY UP THROUGH LINCOLN
COUNTY BASED ON LATEST RADAR TRENDS AND LIGHTNING DATA. -SALMEN-
&&
.PREVIOUS DISCUSSION...256 AM PDT...
.SHORT TERM...THROUGH SATURDAY NIGHT.
THE CALENDAR MIGHT SAY MAY THE WEATHER PATTERN LOOKS MORE LIKE
FEBRUARY WITH AN ACTIVE PACIFIC JET STREAM BRINGING YET ANOTHER
STRONG TROUGH INTO THE SOUTHWEST. THIS STORM WILL IMPACT THE REGION
IN TWO DOSES WITH THE LEAD SHORTWAVE MOVING ONSHORE TODAY AS IT
ROTATES AROUND THE PARENT LOW...FOLLOWED BY THE PARENT LOW WHICH
MOVES ONSHORE IN SOUTHERN CALIFORNIA ON FRIDAY AND DRAGS EAST ACROSS
THE MOJAVE DESERT.
WIDESPREAD HIGH CLOUDS IN ADVANCE OF THIS LEAD SHORTWAVE HAVE
OVERSPREAD THE FORECAST AREA AND WILL CONTINUE TO ADVANCE INTO THE
REGION TODAY WITH CLOUD DECKS LOWERING THROUGH THE DAY. SHOWERS WILL
BREAK OUT FIRST ACROSS THE SIERRA WHERE SNOW LEVELS NEAR 6500 FEET
WILL LEAD TO THE LIKELIHOOD OF ACCUMULATING SNOW THURSDAY AFTERNOON.
WHILE ACCUMULATIONS BY SIERRA STANDARDS WONT BE TOO IMPRESSIVE...
BEING MID-MAY IT CERTAINLY MAY CATCH SOME OFF GUARD. ADDITIONAL
SHOWERS WILL BREAK OUT ACROSS NORTHERN MOHAVE COUNTY WHERE THE PAST
FEW RUNS OF THE HRRR HAVE BROKEN OUT SOME ISOLATED THUNDERSTORMS BY
EARLY AFTERNOON. BY LATER IN THE DAY THURSDAY ADDITIONAL SHOWERS
AND STORMS MAY FORM ACROSS PARTS OF THE MOJAVE DESERT AND EVEN MAY
CREEP INTO THE LAS VEGAS VALLEY. AMOUNTS IN THE DESERTS WILL
GENERALLY BE LIGHT...UNDER A TENTH OF AN INCH.
WINDS WILL AGAIN BE GUSTY TOMORROW AND I TOYED WITH THE IDEA OF A
WIND ADVISORY FOR THE WESTERN MOJAVE DESERT BUT WITH WIDESPREAD
OVERCAST...AND SOME SHOWER ACTIVITY...I DONT THINK MIXING WILL BE
OPTIMAL FOR AN ALREADY BORDERLINE WIND EVENT. SO I DECIDED AGAINST
ANY WIND HEADLINES.
BY FRIDAY...THE PRIMARY LOW MOVES ASHORE IN SOUTHERN CALIFORNIA. GFS
HAS BEEN FAIRLY CONSISTENT ON THE PAST SEVERAL RUNS NOW ON BRINGING
A HEALTHY STRIPE OF PRECIPITATION TO THE MOJAVE DESERT MAINLY SOUTH
OF INTERSTATE 40. QPF NUMBERS BY THE GFS ARE PRETTY SIGNIFICANT BY
MAY STANDARDS WITH 0.25 TO 0.50 INCH AMOUNTS ADVERTISED (KEEP IN
MIND MONTHLY AVERAGE RAINFALL THE ENTIRE MONTH OF MAY IN THIS PART
OF THE DESERT IS CLOSER TO A TENTH OF AN INCH). NAM IS MUCH DRIER
AND ECMWF KEEPS THE BRUNT OF THE MOISTURE FURTHER SOUTH....BUT I DO
LIKE THE GFS CONSISTENCY AND THE SOLUTION MAKES SOME METEOROLOGICAL
SENSE BUT THE NUMBERS ARE EXCESSIVE. I OPTED FOR A MIDDLE GROUND AND
RAISED POPS AND QPF ACCORDINGLY ACROSS THE MOJAVE DESERT ESPECIALLY
SOUTH OF I-40 BUT KEPT RAINFALL TOTALS UNDER A QUARTER OF AN INCH.
FURTHER NORTH PLACES LIKE LAS VEGAS WILL LIKELY SEE A COOL CLOUDY
DAY MUCH LIKE LAST FRIDAY WITH SOME LIGHT SHOWERS AROUND BUT AMOUNTS
AT THIS TIME AGAIN LOOK LIGHT. BE PREPARED FOR DRAMATICALLY COOLER
TEMPERATURES...LIKELY BEING 20 TO 30 DEGREES BELOW SEASONAL
AVERAGES.
ON SATURDAY THE TROUGH WILL DEPART TO THE EAST BUT SOME WRAP AROUND
MOISTURE AND INSTABILITY MAY STILL SPARK SOME CLOUDS AND SHOWERS
ESPECIALLY ACROSS THE SOUTHERN GREAT BASIN AND MOHAVE COUNTY IN
ARIZONA. OTHERWISE TEMPERATURES WILL CREEP UPWARD SLIGHTLY SATURDAY
BUT STILL BE AROUND 15 DEGREES BELOW NORMAL.
.LONG TERM...SUNDAY THROUGH THURSDAY.
SUNDAY...ATTENTION WILL TURN TO THE NEXT DEVELOPING CLOSED LOW OFF
THE CALIFORNIA COAST. SOUTH TO SOUTHWEST FLOW WILL STRENGTHEN AHEAD
OF IT LEADING TO SOUTHERLY SURFACE WINDS GENERALLY GUSTING 20-30 MPH
ACROSS THE FORECAST AREA SUNDAY AFTERNOON. BROAD UPWARD FORCING
AHEAD OF THE LOW WILL COMBINE WITH SOME LINGERING MOISTURE AND
INSTABILITY OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN ZONES
TO PRODUCE SOME AFTERNOON THUNDERSTORMS. THE UPPER LOW IS FORECAST
TO SWING INLAND MONDAY WITH SOME ADDITIONAL MOISTURE MOVING INTO
SOUTHERN NEVADA AND NORTHWEST ARIZONA. DIFFLUENT FLOW AND COOLING
ALOFT WILL HELP DESTABILIZE THE ATMOSPHERE AND LEAD TO MORE
EXTENSIVE COVERAGE AND MORE ORGANIZED BANDS OF CONVECTION EXTENDING
DOWN INTO CLARK AND MOHAVE COUNTIES MONDAY AFTERNOON.
THE UPPER LOW IS FORECAST TO LIFT UP ACROSS THE ROCKIES BY TUESDAY
LEAVING A WEAK BROAD TROUGH OVER THE WESTERN STATES THROUGH
THURSDAY. THE MEDIUM RANGE MODELS ARE ALL IN FAIRLY GOOD AGREEMENT
THAT THIS WILL PROVIDE A PATH FOR YET ANOTHER PACIFIC LOW PRESSURE
SYSTEM TO DROP INTO SOUTHERN NEVADA GOING INTO THE MEMORIAL DAY
WEEKEND. THIS PATTERN WILL KEEP TEMPERATURES SLIGHTLY BELOW NORMAL
THROUGH THE PERIOD WITH A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS
OVER THE SOUTHERN SIERRA AND SOUTHERN GREAT BASIN. THEN...IT IS
LOOKING LIKE THERE WILL BE THE POTENTIAL FOR COOLER AND MORE
UNSETTLED WEATHER HEADING INTO THE MEMORIAL DAY WEEKEND.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES. &&
$$
SHORT TERM/AVIATION...OUTLER
LONG TERM...ADAIR
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION...UPDATED
NWS ALBUQUERQUE NM
1155 AM MDT THU MAY 14 2015
.AVIATION...
18Z TAF CYCLE
ISOLD SH/TS WILL IMPACT NW/NC AND PERHAPS EASTERN PORTIONS OF THE
FORECAST AREA THROUGH THE EARLY/MID EVENING HRS. LIKELY IMPACTS
WOULD BE TO FMN/LVS WITH POSSIBLE IMPACTS TO GUP/TCC. THE IMPACTS
ARE NOT EXPECTED TO BE TOO SIGNIFICANT OTHER THAN TO FMN WHERE A
TEMPO TS IS USED. WILL MONITOR THAT TREND BECAUSE MAYBE TOO
BULLISH WITH THAT SCENARIO. THE NEXT ROUND OF SH SHOULD NOT
SIGNIFICANTLY IMPACT TERMINAL SITES UNTIL AFTER 18Z FRI. WIND FLOW
WILL INCREASE AND ABQ COULD EXPERIENCE PERIODIC GUSTS NEAR 35 KT
LATER THIS AFTERNOON. UNSURE ABOUT AN AWW AT THIS TIME. WILL BE
SOMEWHAT DEPENDENT ON CLEARING CLOUD COVER. OTHER SITES WILL SEE
GUSTS BETWEEN 30-35 KT AT TIMES...GUP/AEG AND LVS. LVS/GUP SHOULD
EXPERIENCE THE HIGHEST WIND VALUES THIS AFTERNOON AND CANT RULE
OUT HIGHER GUSTS. MTN TOP OBSCD WILL BE THE MAIN IMPACTS DUE TO
PASSING SHOWERS ACROSS THE NORTH.
50
&&
.PREV DISCUSSION...330 AM MDT THU MAY 14 2015...
.SYNOPSIS...
ACTIVE WEATHER PATTERN WILL CONTINUE FOR THE FORESEEABLE FUTURE.
SHOWERS AND THUNDERSTORMS WILL BE MOST NUMEROUS OVER THE NORTH AND
WEST TODAY THROUGH SATURDAY...AND A FEW STORMS NEAR THE TEXAS
BORDER MAY BE STRONG TO SEVERE THIS AFTERNOON AND EVENING AND FRIDAY
AFTERNOON AND EVENING. GUSTY SOUTHWEST WINDS WILL AFFECT NORTHEAST
NEW MEXICO FRIDAY AFTERNOON. SOME DRYING SATURDAY NIGHT INTO SUNDAY
THEN A WETTER PERIOD TO FOLLOW MONDAY NIGHT AND TUESDAY.
&&
.DISCUSSION...
WIDESPREAD HIGH CLOUDS ASSOCIATED WITH THE NEXT DISTURBANCE TO
AFFECT NEW MEXICO WILL PERSIST TODAY. PATCHY FOG AT KCAO KEEPS
VARYING AT WINDS FLOP AROUND...WITH MORE WIDESPREAD FOG TO THE NORTH
AND EAST. NOT EXPECTING THAT WILL HANG AROUND FOR VERY LONG THIS
MORNING. RUC SHOWING SOME LIGHT PRECIPITATION DEVELOPING THIS
MORNING OVER THE SRN HIGH TERRAIN SO MADE SOME ADJUSTMENTS FOR THAT.
SPC OUTLOOK BRINGS A MARGINAL AREA INTO THE FAR EAST CENTRAL/SE FOR
TODAY AND GENERALLY A SIMILAR AREA DRAWN FOR FRIDAY AS THE LEAD
DISTURBANCE EXITS. WINDS COULD BE GUSTY FRIDAY SOUTH AND EAST AS H7
WINDS INCREASE TO THE 30-40 KT RANGE. THE MAIN UPPER LOW/FRONT PASS
THROUGH FRIDAY NIGHT/SATURDAY. SOME BIG DISPARITIES POP GUIDANCE
WISE...TOOK A MIDDLE OF THE ROAD APPROACH...BUT IN GENERAL THEY ARE
HIGHER THAN WHAT WAS INHERITED. HIGHS FRIDAY THROUGH SUNDAY BELOW
AVERAGE OVER THE ENTIRE FORECAST AREA...ESPECIALLY SATURDAY...WITH
SOME WARMING SUNDAY. HIGHS STAY PRETTY MUCH NEAR TO BELOW AVERAGE
THROUGH THE MIDDLE OF NEXT WEEK AS YET ANOTHER UPPER LOW AND FRONT
BRING A WETTER PERIOD TO THE REGION MONDAY NIGHT AND TUESDAY.
&&
.FIRE WEATHER...
A FEW SHOWERS AND THUNDERSTORMS...NOT NEARLY AS HEAVY AS WHAT FELL
TUE AND EARLY WED...WILL DEVELOP ACROSS THE FAR NORTHERN PORTION OF
NM THIS AFTN...PRIMARILY ACROSS THE HIGHER TERRAIN. THE FAR WEST MAY
ALSO SEE ISOLATED AFTN AND EVE SHOWER OR STORM ACTIVITY...BUT
MEASURABLE RAINFALL IS UNLIKELY IN MOST CASES. FCST MODELS ARE STILL
PRETTY SUPPORTIVE OF ANOTHER ROUND OF WETTING MOISTURE FRIDAY INTO
SATURDAY AS ANOTHER VIGOROUS AND WET TROUGH ALOFT APPROACHES AND
MOVES ACROSS THE CENTRAL AND SOUTHERN ROCKIES. WETTING RAIN/HIGHER
ELEVATION SNOW WITH THIS SYSTEM IS EXPECTED TO FAVOR THE WESTERN
HALF OF NORTH AND CENTRAL NM...THOUGH THERE APPEARS TO BE SOME
INCREASE IN THE CHANCE FOR A FEW STRONG THUNDERSTORMS ACROSS THE
EAST HALF OF THE EASTERN PLAINS. CONFIDENCE REMAINS PRETTY HIGH AS
FCST MODELS HAVE BEEN GETTING MORE CONSISTENT ON THIS SCENARIO OVER
THE PAST SEVERAL MODEL RUNS. VENTILATION WILL BE EXCELLENT NEARLY
ALL AREAS THE NEXT 3 AFTNS DUE LARGELY TO THE STRONGER TRANSPORT
WINDS. MODEL DERIVED MIXING HEIGHTS STILL MAY BE A BIT TOO HIGH
GIVEN CLOUD COVER AND GENERALLY BELOW NORMAL TEMPS...SO THERE MAY
STILL BE A FEW MORE POCKETS OF VERY GOOD RATHER THAN EXCELLENT
VENTILATION THAN CURRENTLY INDICATED. RATES WILL DROP SHARPLY
SUN...BUT THEN PICK BACK UP SHARPLY AGAIN FOR EARLY TO MID WEEK NEXT
WEEK. SAT APPEARS TO BE THE COOLEST DAY WITH SNOW LEVELS AT THEIR
LOWEST... POSS GETTING AS LOW AS 8500 TO 9500 FEET ACROSS THE NORTH
AND WEST CENTRAL COUNTIES. FRI APPEARS TO BE THE WINDIEST DAY...
PARTICULARLY ACROSS THE NE THIRD OF THE FCST AREA.
STILL LOOKING AT A BREAK IN THE SHOWERY/COOLER WEATHER SUN INTO MUCH
OF MON WITH SOME SHORTWAVE RIDGING AHEAD OF ANOTHER PACIFIC TROUGH.
BACK DOOR COLD FRONT INTRUSION INTO AT LEAST THE EAST HALF OF THE
STATE SUNDAY NIGHT AND MON TO INCREASE MOISTURE SOME INITIALLY WITH
AN ADDED BOOST FROM GULF MOISTURE LATER MON INTO TUE SHOULD
ENCOURAGE DEVELOPMENT OF ANOTHER ROUND OF SHOWERS/THUNDERSTORMS...
MAINLY ALONG THE CENTRAL MOUNTAIN CHAIN ON EAST. BUT THERE IS ALSO
SOME POTENTIAL FOR SPOTTY ACTIVITY BETWEEN THE DIVIDE AND THE
CENTRAL MTN CHAIN AS MODELS MORE OFTEN THAN NOT KEEP THE MOISTURE
FARTHER EAST THAN WHAT IS OFTEN THE CASE. IN FACT SOME MODELS ARE
BEGINNING TO CREEP THE WETTING PRECIP FARTHER WEST ON MOST RECENT
COUPLE OF RUNS. THIS WESTWARD CREEP WILL CONTINUE TO BE MONITORED.
ANOTHER PACIFIC TROUGH SHOULD APPROACH THE AREA LATE NEXT WEEK. NOT
LOOKING AT ANY ORGANIZED CRITICAL FIRE WEATHER GROWING EVENTS NEXT
WEEK ALTHOUGH SUSPECT THERE WILL BE SOME AFTERNOON BREEZES. PRECIP
COVERAGE IS STILL UNCERTAIN...BUT AT THIS TIME LOOKS TO BE A LITTLE
FARTHER EAST THAN WHAT WAS THE CASE THIS PAST TUE/WED PERIOD.
43
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
141 PM CDT THU MAY 14 2015
.UPDATE...
ISSUED AT 142 PM CDT THU MAY 14 2015
MAIN UPDATE WAS TO SKY AND TEMPERATURES. LOW STRATUS PERSISTING
ACROSS THE WEST. LAST FEW RUNS OF THE HRRR STILL TRENDS MOSTLY
SUNNY...JUST WILL BE A BIT LATER THAN PREVIOUSLY THOUGHT. THIS
IMPACTED DAYTIME HIGHS ACROSS THE WEST...LOWERING A FEW DEGREES.
UPDATE
ISSUED AT 1029 AM CDT THU MAY 14 2015
SURFACE LOW PRESSURE CENTERED OVER WESTERN NEBRASKA WITH A QUASI-
STATIONARY SURFACE FRONT EXTENDING FROM THE LOW NORTH-NORTHEAST
ACROSS THE CENTRAL DAKOTAS INTO NORTHEASTERN NORTH DAKOTA. STRONG
MID LEVEL S/WV TROUGH LIFTING ACROSS THE EASTERN DAKOTAS TOWARDS
THE UPPER MISSISSIPPI VALLEY REGION. SHOWERS...SOME AREAS
MODERATE...CONTINUE ALONG THE FRONTAL ZONE ACROSS SOUTH CENTRAL
NORTH DAKOTA INTO NORTHEASTERN NORTH DAKOTA THIS MORNING. RAINFALL
AMOUNTS WITHIN THE BAND HAVE GENERALLY BEEN IN THE RANGE OF
0.5-0.75"...WITH AMOUNTS IN EARLIER CONVECTIVE BANDS IN EXCESS OF
AN INCH.
SHOWERS WILL CONTINUE TO SLOWLY LIFT NORTH AND EAST AS THE DAY
PROGRESSES...AND SHOULD BE ENTIRELY OUT OF MY EASTERN COUNTIES BY
03Z.
OTHER UPDATE WITH THIS FORECAST PACKAGE WAS TO LOWER TEMPERATURES
CENTRAL AS LOW CLOUD COVER IS NOW FORECAST TO PERSIST THROUGH THE
AFTERNOON AS PER THE LAST FEW HIGH RES HRRR MODEL RUNS ALONG WITH
THE LATEST NAM/RAP LOW LEVEL RH FORECAST. STILL EXPECT CLEARING
WEST...THOUGH STRATUS FIELD IS EXTENSIVE. HIGH RES MODELS INDICATE
OVC CIGS TRENDING FEW-SCT 16-19Z ACROSS MY WEST...SO WILL MONITOR
IN CASE CLOUD COVER NEEDS TO BE INCREASED AND TEMPS DROPPED.
UPDATE ISSUED AT 640 AM CDT THU MAY 14 2015
SHOWERS CONTINUE TO LIFT SLOWLY NORTHWARD ACROSS CENTRAL AND
EASTERN NORTH DAKOTA. LATEST BOWMAN RADAR SHOWS RETURNS DRYING UP
OVER WESTERN NORTH DAKOTA...THUS CURRENT RADAR TRENDS LOOK GOOD.
OTHERWISE NO SIGNIFICANT UPDATES TO THE CURRENT FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 346 AM CDT THU MAY 14 2015
FORECAST HIGHLIGHTS IN THE SHORT TERM PERIOD WILL BE WIDESPREAD
SHOWERS TODAY WITH SOME AREAS CENTRAL SEEING HEAVY RAINFALL.
CURRENTLY...AN UPPER LEVEL LOW/SHORTWAVE LIFTING NORTHEAST THROUGH
THE CENTRAL AND NORTHERN PLAINS WAS ASSOCIATED WITH WIDESPREAD
SHOWERS AND A FEW EMBEDDED THUNDERSTORMS ACROSS THE STATE. LIGHTNING
ACTIVITY HAD DECREASED IN THE LAST HOUR...AND MESOANALYSIS INDICATES
THAT CAPE HAS DECREASED ACROSS THE REGION. AT THE SURFACE...LOW
PRESSURE WAS OVER WYOMING WITH A WARM FRONT EXTENDING FROM THE LOW
NORTHEASTWARD TO NEAR FORT YATES TO NEAR DEVILS LAKE TO THE
NORTHEAST CORNER OF NORTH DAKOTA.
FORECAST CAPE VALUES FOR TODAY ARE LOW ENOUGH TO KEEP THE MENTION OF
THUNDER OUT OF THE FORECAST FOR THE DAYTIME PERIOD. PRECIPITABLE
WATER FORECASTS OF 1.00" TO 1.20" FOR SOUTH CENTRAL NORTH
DAKOTA...ALONG THE SURFACE WARM FRONT. WIDESPREAD AREAS OF 0.50" OF
RAIN ARE POSSIBLE TODAY ALONG AND EAST OF A LINE FROM THE TURTLE
MOUNTAINS TO BISMARCK/MANDAN TO GRANT COUNTY. LOCALLY HIGHER AMOUNTS
ARE POSSIBLE.
THE UPPER LEVEL SHORTWAVE AND SURFACE WARM FRONT ARE PROGGED TO MOVE
EAST TODAY. EXPECT SHOWERS TO DECREASE FROM WEST TO EAST
TODAY...LINGERING IN CENTRAL NORTH DAKOTA THIS AFTERNOON BEFORE
TAPERING OFF DURING THE EVENING HOURS. AS THE SURFACE WARM FRONT
MOVES EAST...HIGH PRESSURE IN SOUTH CENTRAL CANADA WILL PUSH
SOUTHWARD INTO THE STATE. HIGHS TODAY SHOULD RANGE IN THE 50S TO
LOWER 60S...WITH LOWS TONIGHT FROM THE UPPER 30S TO MID 40S.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 346 AM CDT THU MAY 14 2015
STRONG VERTICALLY STACKED SYSTEM WILL INFLUENCE THE WEATHER ACROSS
THE NORTHERN PLAINS FRIDAY THROUGH SUNDAY. MAIN FORECAST ISSUES IN
THE LONG TERM ARE SEVERE POTENTIAL ON SATURDAY...PRECIPITATION
AMOUNTS AND POSSIBLE LOCALIZED FLOODING ISSUES THROUGH THE WEEKEND
AND THE POTENTIAL FOR FREEZING TEMPERATURES MONDAY TUESDAY
MORNINGS ON THE BACK SIDE OF THIS SYSTEM.
WE START OFF ON A QUIET NOTE FRIDAY AS THE UPPER LEVEL SYSTEM
TRACKS ACROSS THE INTER-MOUNTAIN WEST AND BEGINS TO TAKE SHAPE
OVER THE NORTHERN HIGH PLAINS. WE BEGIN THE DAY DRY WITH SURFACE
HIGH PRESSURE OVER THE FORECAST AREA. SOUTHEAST FLOW ALOFT WILL
INCREASE OVER WESTERN NORTH DAKOTA AS CYCLOGENESIS TAKES PLACE
OVER THE NORTHERN AND CENTRAL HIGH PLAINS. PRECIPITATION IS
EXPECTED TO DEVELOP BY AFTERNOON OVER THE SOUTHWEST AND BEGIN TO
SPREAD NORTH AND EAST.
FRIDAY NIGHT THROUGH SATURDAY MORNING...STRONG WARM ADVECTION
ENVELOPES WESTERN AND CENTRAL NORTH DAKOTA WITH A SURFACE AND
UPPER LOW DEVELOPING OVER NORTHEAST MONTANA. MODELS ARE PRETTY
SIMILAR IN BRINGING A BAND OF PRECIPITATION SOUTHWEST TO NORTHEAST
ACROSS THE FORECAST AREA FRIDAY NIGHT INTO SATURDAY MORNING...WITH
THE MAJORITY OF THE PRECIPITATION OVER THE NORTHERN TIER COUNTIES
ALONG THE DEFORMATION ZONE BY MIDDAY SATURDAY. INSTABILITY ALOFT
IS LIMITED INITIALLY BUT IS EXPECTED TO INCREASE DURING THE NIGHT
ACROSS NORTHERN SOUTH DAKOTA INTO SOUTHERN NORTH DAKOTA. MOST
UNSTABLE CAPES OF 500-1000 J/KG WITH 20-40KTS OF 0-6KM SHEAR LAY
ACROSS THE NORTHERN SOUTH DAKOTA BORDER LATE FRIDAY NIGHT INTO
EARLY SATURDAY MORNING. THUS A THREAT OF SEVERE WEATHER CAN NOT BE
RULED OUT DURING THIS PERIOD...BUT EXPECT THE BETTER THREAT WILL
REMAIN SOUTH OF THE BORDER.
SATURDAY AFTERNOON...POSSIBLY AS EARLY AS LATE SATURDAY MORNING
THE FIRST WAVE OF PRECIPITATION WILL HAVE MOVED THROUGH AND MODELS
SUGGEST A DRY SLOT WORKING INTO CENTRAL NORTH DAKOTA AS AN 80 KT
UPPER LEVEL JET PUSHES INTO EASTERN NORTH DAKOTA BY AROUND MIDDAY
SATURDAY. THIS SHOULD ALLOW FOR A DESTABILIZING ATMOSPHERE DURING
THE LATE MORNING AND AFTERNOON AS SURFACE TEMPERATURES RISE INTO
THE 70S ACROSS THE SOUTHERN HALF OF THE STATE. A STRONG SOUTHERN
STREAM JET OVER THE SOUTHWEST U.S. BEGINS LIFTING INTO THE
SOUTHERN AND CENTRAL PLAINS...ALLOWING THE NORTHERN STACKED SYSTEM
OVER EASTERN MONTANA TO BEGIN MOVING EAST. ALTHOUGH DIRECTIONAL
SHEAR IS NOT IMPRESSIVE...SUFFICIENT BULK SHEAR AND CAPE WILL BE
AVAILABLE DURING THE LATE MORNING THROUGH THE AFTERNOON THAT
SEVERE STORMS ARE POSSIBLE. WILL STILL NEED TO MONITOR TRENDS OF
THE NEXT DAY OR SO TO HOPEFULLY GET A BETTER IDEA.
SATURDAY NIGHT THROUGH SUNDAY...ANY SEVERE WEATHER THREAT SATURDAY
SHOULD QUICKLY DIMINISH FROM WEST TO EAST SATURDAY NIGHT INTO
SUNDAY MORNING AS THE SURFACE LOW CONTINUES TO TRACK EAST ACROSS
THE DAKOTAS. STRONG NORTHERLY FLOW WILL BRING MUCH COOLER
TEMPERATURES FROM WEST TO EAST SUNDAY...WITH MAINLY IN THE 40S
NORTH AND WEST...TO THE LOWER 60S SOUTHEAST. THE STRONG SOUTHERN
SHORTWAVE LIFTING THROUGH THE SOUTHERN AND CENTRAL PLAINS SATURDAY
MOVES INTO THE NORTHERN PLAINS SUNDAY AND MERGES WITH THE STACKED
SYSTEM TRACKING ACROSS THE DAKOTAS. BY SUNDAY AFTERNOON THE THREAT
OF SEVERE WEATHER WILL BE TO THE EAST OF THE DAKOTAS...BUT A BAND
OF PRECIPITATION IN THE DEFORMATION ZONE IS EXPECTED OVER EASTERN
AND POSSIBLY BACK INTO CENTRAL NORTH DAKOTA. THUS SOME PRETTY
HEFTY PRECIPITATION AMOUNTS COULD FALL OVER SOUTH CENTRAL INTO
NORTHEAST NORTH DAKOTA. WILL NEED TO MONITOR FOR SOME AREAS
RECEIVING ENOUGH RAIN TO PRODUCE LOCAL FLOODING ISSUES. ESPECIALLY
IF THEY GET HIT WITH PRECIPITATION A FEW TIMES BEFORE THIS.
PRECIPITATION FINALLY MOVES OUT OF THE AREA BY SUNDAY EVENING WITH
COLD HIGH PRESSURE BUILDING OVER THE AREA INTO EARLY NEXT WEEK.
WITH THE SURFACE HIGH MOVING INTO NORTH DAKOTA BY MONDAY MORNING
IT LOOKS LIKE A GOOD BET THAT WE WILL NEED A FROST ADVISORY OR
MORE LIKELY A FREEZE WARNING...IF CURRENT TEMPERATURE TRENDS HOLD.
WE COULD STILL BE DEALING WITH FROST ON TUESDAY MORNING AS WELL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 142 PM CDT THU MAY 14 2015
WIDESPREAD MVFR-IFR CONDITIONS WILL CONTINUE MOST LOCATIONS TODAY.
SHRA WILL ALSO CONTINUE TO SPREAD NORTH AND EAST...ENDING AT KJMS
22-00Z. CONDITIONS SHOULD STILL IMPROVE TO VFR OVER PORTIONS OF
NORTHWEST NORTH DAKOTA LATER THIS THURSDAY AFTERNOON...WHILE MOST
AREAS WILL REMAIN IFR-MVFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...JV
LONG TERM...TWH
AVIATION...NH
AREA FORECAST DISCUSSION
NWS AMARILLO TX
417 PM CDT THU MAY 14 2015
.DISCUSSION...
WATER VAPOR CHANNEL AND VISIBLE BOTH SHOW EXTENSIVE HIGH LEVEL
MOISTURE/CIRRUS STREAMING NORTHEASTWARD ACROSS NEW MEXICO INTO THE
SOUTHERN AND CENTRAL PLAINS AHEAD OF A DEEP WEST COAST MID-UPPER
LOW. CURRENT OBSERVATIONS SHOW SOUTHERLY SURFACE WINDS AND NEAR
NORMAL TEMPERATURES FOR MID MAY ACROSS OUR REGION. THE SHALLOW MOIST
LAYER EVIDENT IN 12Z KAMA AND KMAF SOUNDINGS HAS MIXED OUT SOME THIS
AFTERNOON WITH A SLIGHT DOWNWARD TREND IN SURFACE DEW POINTS NOTED
IN REGIONAL OBSERVATIONS. SLIGHT BACKING TO SURFACE WINDS AND UPSTREAM
DEEPER MOISTURE HAS KEPT SURFACE DEW POINTS FROM MIXING OUT FURTHER
AND SHORT TERM MODEL FORECAST SOUNDINGS SHOWS GRADUAL DEEPENING OF
LOW LEVEL MOISTURE THROUGH THE EVENING. MODEST MLCAPE IS PRESENT
ACROSS THE AREA BUT EFFECTIVE BULK SHEAR IS MARGINAL AT BEST FOR
STORM ORGANIZATION AND SEVERE WEATHER POTENTIAL. A FEW MARGINALLY
SEVERE THUNDERSTORMS ARE STILL POSSIBLE THIS EVENING. VIS SAT/RADAR
AND LIGHTNING OBS SHOW ISOLATED/SCATTERED CONVECTIVE DEVELOPMENT SO
FAR LIMITED TO SOUTHEAST AND CENTRAL NEW MEXICO AND SOUTHEAST
COLORADO. CU FIELD HAS EXPANDED FURTHER EAST BENEATH CIRRUS SHIELD
ACROSS EASTERN NEW MEXICO AND AS WEAK SHORTWAVE TROUGH APPROACHES
CONVECTION SHOULD EXPAND. CURRENT THINKING IN HOW THIS EVOLVE ALIGNS
WELL WITH WRF AND HRRR MODEL PROGNOSTICATIONS AND RESEMBLE OUTPUT
FROM THESE REASONABLY WELL.
A PATTERN SIMILAR TO WHAT HAS BEEN SEEN RECENTLY AND ONE THAT IS
GENERALLY RECOGNIZED FOR BRINGING OUR REGION HIGHER PROBABILITY
PRECIPITATION CHANCES CONTINUES THROUGH THE FORECAST PERIOD. AFTER
THE DEPARTING WAVE EARLY TOMORROW THE FOCUS SHIFTS TO A PERIOD OF
ASCENT WITH ANOTHER APPROACHING SHORTWAVE AND THIS WILL RESULT IN
ANOTHER FAIRLY HIGH CONFIDENCE ROUND OF PRECIPITATION FRIDAY EVENING
AND OVERNIGHT. MADE MINOR ADJUSTMENTS TO TIMING AND INCREASED BOTH
QPF AND PRECIPITATION PROBABILITIES. MODELS ARE NOT TOO DISSIMILAR
WITH TIMING OF WHAT COULD BE A FAIRLY EXPANSIVE AREA OF
RAIN/THUNDERSTORMS EXITING THE AREA SATURDAY MORNING AND HAVE KEPT
PRECIPITATION CHANCES ACROSS THE EASTERN PORTION OF THE AREA THEN. BY
AFTERNOON MODEL DIFFERENCES IN POSITION OF THE DRYLINE LEAD TO SOME
UNCERTAINTY WITH WHERE CONVECTION WILL REDEVELOP. THE CONSENSUS IS
THIS WILL OCCUR NEAR THE TEXAS/OKLAHOMA STATE LINE...OR SLIGHTLY
WEST. THUS...RETAINED SLIGHT/LOW CHANCE POPS ACROSS THE EASTERNMOST
COUNTIES SATURDAY AFTERNOON. BEHIND THE DRYLINE...DEEP MIXING INTO
FAIRLY STRONG MOMENTUM ALOFT COULD RESULT IN A PERIOD OF NEAR
ADVISORY CRITERIA WINDS ACROSS PORTIONS OF THE AREA.
QUITE WEATHER IS EXPECTED SUNDAY IN BETWEEN TWO WAVES IN A REGION OF
MEAN HEIGHT RISES DUE TO LOW AMPLITUDE RIDGING. YET ANOTHER SYSTEM
TAKES A SIMILAR TRACK AS THE LAST FEW DOWN THE WEST COAST AND INTO
THE DESERT SOUTHWEST BY LATE MONDAY. INCREASING LARGE SCALE ASCENT
AND DEEPENING MOISTURE (PWATS RISING TO WELL ABOVE CLIMATOLOGY)
SHOULD JUSTIFY FAIRLY HIGH PRECIPITATION PROBABILITIES FROM MONDAY
NIGHT THROUGH TUESDAY. THEREAFTER MEDIUM RANGE MODELS DIVERGE BUT THE
GENERAL SOUTHWESTERLY FLOW PATTERN WITHOUT ANY ANTECEDENT SIGNIFICANT
SOUTHEASTWARD PUSH OF LOW LEVEL MOISTURE NECESSITATES AT LEAST LOW
PRECIPITATION PROBABILITIES THROUGH MID WEEK.
BRB
&&
.PRELIMINARY POINT TEMPS/POPS...
AMARILLO TX 56 81 57 80 48 / 50 10 60 20 5
BEAVER OK 62 84 59 82 50 / 40 20 60 50 20
BOISE CITY OK 53 79 50 73 47 / 30 10 40 10 5
BORGER TX 60 83 59 79 53 / 50 10 60 20 5
BOYS RANCH TX 55 81 58 78 48 / 50 10 60 10 5
CANYON TX 56 80 57 79 49 / 50 10 60 10 5
CLARENDON TX 59 82 59 80 51 / 50 20 60 30 5
DALHART TX 52 80 54 75 46 / 40 10 50 10 5
GUYMON OK 57 82 56 79 49 / 40 10 50 20 10
HEREFORD TX 54 80 57 77 49 / 40 10 60 10 5
LIPSCOMB TX 62 83 61 81 53 / 50 20 60 50 20
PAMPA TX 59 80 57 78 49 / 50 10 60 30 5
SHAMROCK TX 63 82 63 81 53 / 50 20 60 50 20
WELLINGTON TX 64 84 63 83 54 / 50 20 60 60 20
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
OK...NONE.
&&
$$
08/17
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
326 PM CDT THU MAY 14 2015
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 326 PM CDT THU MAY 14 2015
PRIMARY FORECAST CHALLENGES INCLUDE EXITING SHOWERS THIS EVENING...
THEN THUNDERSTORM CHANCES AND SEVERE POTENTIAL FRIDAY NIGHT AND
AGAIN SUNDAY AFTERNOON AND EVENING. 14.12Z MODEL SUITE IN GOOD
OVERALL AGREEMENT AND WILL USE A BLENDED APPROACH.
SO FAR TODAY...RAIN HAS BEEN VERY SLOW TO MOVE EAST PAST THE MS
RIVER DUE TO DRY SUB-600 HPA LAYER. HOWEVER...AS SHORT-WAVE ALOFT
CURRENTLY ACROSS THE EASTERN DAKOTAS INTO SOUTHWEST MN/WESTERN IA
LIFTS TO THE NORTHEAST...RAIN SHOWERS WILL MOVE ACROSS THE REST OF
THE UPPER MS RIVER VALLEY LATE THIS AFTERNOON AND EVENING. SHOWERS
WILL TAPER OFF FROM WEST TO EAST AFTER MIDNIGHT...BUT OVERCAST
SKIES OVERNIGHT WILL KEEP TEMPERATURES ELEVATED IN THE 50S.
FRIDAY WILL BE WARMER AND DRY AS SHORT-WAVE RIDGING MOVES ACROSS
THE REGION. 925 HPA TEMPERATURES RISE TO BETWEEN +14 AND +18
CELSIUS BY 00Z SATURDAY...BUT A MIX OF SUN AND CLOUDS SHOULD
RESULT IN AFTERNOON HIGHS RISING INTO THE UPPER 60S ACROSS NORTH
CENTRAL WI TO THE MID 70S ACROSS PORTIONS OF NORTHEAST IA AND
SOUTHWEST WI. WINDS WILL BE LIGHT AND VARIABLE THROUGH THE DAY.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 326 PM CDT THU MAY 14 2015
FRIDAY EVENING AND OVERNIGHT...SURFACE LOW PRESSURE WILL LIFT
FROM THE CENTRAL PLAINS INTO THE DAKOTAS AS A LARGE PACIFIC
TROUGH ACROSS THE WESTERN CONUS BEGINS TO PUSH EAST. AN EAST-WEST
ORIENTED WARM FRONT WILL MOVE NORTH INTO THE UPPER MS RIVER VALLEY
WITH 0 TO 3 KM MUCAPE INCREASING TO BETWEEN 500 AND 1500 J/KG
MAINLY SOUTH OF THE I-90 CORRIDOR. AT THE SAME TIME...SHEAR WILL
BE WEAK AROUND 20 KTS OR LESS. SOME ELEVATED STRONG TO LOCALLY
SEVERE THUNDERSTORMS ARE POSSIBLE...BUT COVERAGE WILL BE LIMITED.
PRIMARY THREATS ARE LARGE HAIL AND STRONG WIND.
SATURDAY WILL BE WARM AND HUMID WITH INCREASING LOW-LEVEL MOISTURE/
WARM AIR ADVECTION. 925 HPA TEMPERATURES NEARING +20 CELSIUS WILL
BRING AFTERNOON HIGHS IN THE UPPER 70S TO LOWER 80S. SURFACE DEW
POINT TEMPERATURES WILL ALSO RISE IN THE 60S. AS A RESULT...
INSTABILITY WILL RISE ABOVE 2000 J/KG IN PLACES SATURDAY AFTERNOON...
BUT FORCING/SHEAR IS VERY WEAK WITH CONTINUED RIDGING ALOFT. SOME
SCATTERED SHOWERS AND THUNDERSTORMS COULD DEVELOP...BUT NOT ENOUGH
TO WARRANT ANY MORE THAN A 20 TO 30 PERCENT CHANCE. 0 TO 6 KM
MUCAPE TO REMAIN AT OR BELOW 500 J/KG SATURDAY NIGHT WITH CONCURRENT
DEEP LAYER SHEAR LESS THAN 30 KTS. AGAIN...SOME SCATTERED SHOWERS/
THUNDERSTORMS POSSIBLE OVERNIGHT...BUT MORE SIGNIFICANT CONVECTION
WILL BE FARTHER WEST ACROSS THE PLAINS WHICH COULD PROPAGATE IN
SOME WAY INTO THE UPPER MS RIVER VALLEY BY SUNDAY MORNING.
BEST CHANCE FOR SEVERE CONVECTION ACROSS THE FORECAST AREA WILL BE
SUNDAY AFTERNOON AND EVENING AS A STRONG COLD FRONT SWEEPS ACROSS
THE UPPER MS RIVER VALLEY. 0 TO 6 KM SHEAR INCREASES TO BETWEEN
40 AND 50 KTS...20 TO 30 KTS OF WHICH ARE IN THE 0 TO 1 KM LAYER.
MUCAPE IN THE 0 TO 3 KM LAYER INCREASES TO BETWEEN 1500 AND 2000
J/KG BY 18Z SUNDAY AND WHEN COMBINED WITH STRONG MID-LEVEL
MOISTURE TRANSPORT...EXPECT SHOWERS AND THUNDERSTORMS TO DEVELOP...
SOME OF WHICH MAY BE SEVERE. EARLY SUNDAY MORNING CONVECTION FROM
THE PLAINS COMBINED WITH THE SPEED OF THE OVERALL SYSTEM AND
POTENTIAL DRY SLOTTING DO INTRODUCE SOME UNCERTAINTY...BUT LARGE
HAIL AND STRONG WINDS ARE POSSIBLE WITH ANY STRONGER STORMS THAT
DEVELOP. CANNOT RULE OUT AN ISOLATED TORNADO AS WELL GIVEN
STRENGTH OF THE SHEAR. WILL BE ABLE TO FINE-TUNE THE DETAILS OVER
THE COMING DAYS...BUT FOR NOW...PERSONS WITH OUTDOOR PLANS ON
SUNDAY SHOULD PAY CLOSE ATTENTION TO THE LATEST FORECASTS/
STATEMENTS.
COLD FRONT TO SWEEP ACROSS THE AREA SUNDAY NIGHT...RESULTING IN A
MUCH COOLER AND DRY AIR MASS FOR MUCH OF NEXT WEEK. DAILY HIGHS
MONDAY THROUGH THURSDAY UNLIKELY TO BREAK ABOVE THE LOWER 60S WITH
OVERNIGHT LOWS FROM THE MID 30S INTO THE 40S. BROAD SURFACE HIGH
PRESSURE WILL KEEP CONDITIONS MOSTLY DRY...ALTHOUGH THERE IS A
SLIGHT CHANCE FOR SHOWERS WEDNESDAY/THURSDAY AS FLOW ALOFT BECOMES
A BIT MORE ZONAL WITH WEAK SHORT-WAVES MOVING THROUGH THE CENTRAL
CONUS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1206 PM CDT THU MAY 14 2015
THE LIGHT RAIN HAS BEEN VERY SLOW TO ADVANCE EAST TODAY DUE TO THE
DRY AIR IN PLACE OVER WISCONSIN. THE 14.15Z HRRR INDICATES THIS
TREND WILL CONTINUE THROUGH THE AFTERNOON WITH THE LIGHT
RAIN/SPRINKLES NOT REACHING KLSE UNTIL THE MIDDLE OF THE
AFTERNOON. THERE IS ALSO A TREND IN THE HI-RES MESO MODELS THAT
THE ACTIVITY COMING UP OUT OF MISSOURI WILL BECOME THE MORE
DOMINANT AREA OF RAIN CAUSING A DRY SLOT TO DEVELOP NORTH OF IT
AND OVER THE AREA. SOME SUGGESTIONS IN THE REGIONAL RADAR DISPLAY
THAT THIS IS INDEED OCCURRING AND THAT IT WILL TAKE THE MORE
WIDESPREAD ACTIVITY OVER WESTERN IOWA TO SPREAD IN BEFORE THERE
WILL LIKELY BE ANY VISIBILITY RESTRICTIONS OCCURRING. HAVE THUS
PUSHED BACK THE TIMING OF MVFR VISIBILITY AT KLSE UNTIL EARLY THIS
EVENING BUT STILL SHOW IT BY LATE AFTERNOON AT KRST DUE MORE SO TO
SOME LIGHT FOG DEVELOPING AS THE LOW LEVELS CONTINUE TO SATURATE.
CEILINGS WILL ALSO CONTINUE TO COME DOWN WITH THIS SATURATION WITH
KRST EXPECTED TO GO TO IFR THIS AFTERNOON AND KLSE COMING DOWN TO
MVFR THIS EVENING. THE RAIN SHOULD END BY MID TO LATE EVENING WITH
BOTH SITES STAYING IFR/MVFR UNTIL FRIDAY MORNING AS THE WINDS
START TO PICK UP OUT OF THE NORTHWEST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...ROGERS
LONG TERM...ROGERS
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1206 PM CDT THU MAY 14 2015
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 307 AM CDT THU MAY 14 2015
WATER VAPOR IMAGERY THIS MORNING SHOWS A VIGOROUS MID-LEVEL TROUGH
LIFTING NORTHEAST ACROSS THE PLAINS WHILE A RIDGE OF HIGH PRESSURE
EXTENDED N/S ACROSS OUR AREA. FORCING FROM THIS TROUGH WAS PRODUCING
A WIDESPREAD SWATH OF SHOWERS ACROSS EASTERN NEB/WESTERN IA...
PUSHING NORTHEAST TOWARD THE AREA. OTHERWISE...PLENTY OF HIGH/MID
CLOUD ACROSS THE FORECAST AREA WITH TEMPERATURES AT 2 AM RANGING
FROM THE LOWER/MID 40S ACROSS NORTHERN AND CENTRAL WI...TO THE
MIDDLE 50S ALONG AND WEST OF THE MISSISSIPPI RIVER.
LOOK FOR THAT MID-LEVEL TROUGH TO CONTINUE LIFTING NORTHEAST INTO
CENTRAL MN/IA BY LATE THIS AFTERNOON. GOOD AMOUNT OF 850-300MB PV-
ADVECTION AND 850MB MOISTURE TRANSPORT WILL CONTINUE TO FUEL SHOWERS
AS THEY SLOWLY PUSH INTO THE AREA FROM WEST TO EAST. DRIER LOWER
LEVELS ASSOCIATED WITH DEPARTING SURFACE HIGH PRESSURE WILL LIKELY
HOLD BULK OF THE SHOWERS WEST OF THE MISSISSIPPI RIVER THROUGH
NOON...BEFORE THEY OVERSPREAD THE REST OF THE AREA THROUGH THE
AFTERNOON HOURS. DUE TO THE CLOUDS AND INCOMING SHOWERS...
TEMPERATURES WILL SUFFER SOMEWHAT...RANGING FROM THE UPPER 50S TO
THE LOWER 60S.
SHOWERS WILL CONTINUE THROUGH MIDNIGHT ACROSS MOST OF THE
AREA...THEN START A SLOW DIMINISHING TREND FROM WEST TO EAST AFTER
MIDNIGHT AS THE TROUGH DEPARTS EAST AND RIDGING BUILDS IN FROM
MN/IA. OVERNIGHT LOWS ARE EXPECTED TO DIP INTO THE UPPER 40S TO THE
MIDDLE 50S.
APPEARS RAINFALL FROM THIS SYSTEM WILL BE SOMEWHERE IN THE 1/2 TO
3/4 INCH RANGE.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 307 AM CDT THU MAY 14 2015
A FEW VERY LIGHT SHOWERS MAY BE ONGOING EARLY FRIDAY MORNING EAST OF
THE MISSISSIPPI RIVER EARLY IN THE MORNING AS THE TROUGH DEPART...
BUT SKIES ARE EXPECTED TO BECOME PARTLY CLOUDY BY AFTERNOON AS A
RIDGE OF HIGH PRESSURE WORKS INTO THE AREA. PLAN ON HIGHS IN THE
UPPER 60S THE THE LOWER 70S.
FOCUS THEN SHIFTS TO THE POTENTIAL FOR SOME STRONG TO SEVERE STORMS
THROUGH THE WEEKEND.
MODELS HAVE BEEN CONSISTENT IN PUSHING A WARM FRONT NORTHWARD
INTO/ACROSS THE AREA FRIDAY NIGHT THROUGH SATURDAY. INCREASING 850MB
MOISTURE TRANSPORT INTO/OVER THE WARM FRONT IS EXPECTED TO FUEL
SCATTERED THUNDERSTORM ACTIVITY. NAM SHOWING MUCAPE OF 1500-2000J/KG
LATE FRIDAY NIGHT INTO SATURDAY MORNING WITH 0-3KM SHEAR OF 20-25KT.
SO...LOOKS LIKE WE HAVE THE POTENTIAL TO GET A FEW STRONGER/MAINLY
PULSE TYPE THUNDERSTORMS AHEAD OF THE FRONT AS IT PUSHES NORTH
INTO/THROUGH THE AREA. THE FRONT LOOKS LIKE IT WILL PUSH NORTH OF
THE AREA BY LATE MORNING...LEAVING OUR AREA IN A WEAKLY CAPPED
ENVIRONMENT WITH WARM/HUMID AIRMASS IN PLACE. MAY HAVE TO WATCH
CLOSELY FOR SEVERE THUNDERSTORM POTENTIAL DURING THE AFTERNOON WHERE
NAM IS PRODUCING MUCAPE IN THE 3000-5000J/KG RANGE ALONG WITH 0-3KM
BULK SHEAR OF 25-30KT. NAM INSTABILITY MAY BE A BIT OVERDONE BASED
ON 70 DEGREE OUTPUT DEWPOINTS...BUT LOWER/MID 60S DEW POINTS LOOK
REALISTIC WHICH WOULD YIELD CAPE IN THE 2000-4000J/KG. LOOKS LIKE
HIGHEST SEVERE POTENTIAL WOULD BE WESTERN PORTIONS OF THE AREA WHERE
STEEPER MID-LEVEL LAPSE RATES/HIGHER-END OF THE BULK SHEAR WILL
EXIST. OTHERWISE...LOOK FOR HIGHS IN THE UPPER 70S TO THE LOWER 80S.
SHOWERS AND THUNDERSTORMS WILL LIKELY INCREASE IN COVERAGE FROM WEST
TO EAST SATURDAY NIGHT THROUGH SUNDAY AS FAIRLY STRONG SURFACE
CYCLOGENESIS TAKES PLACE OVER THE NORTHERN PLAINS...FUELING STRONGER
MOISTURE TRANSPORT/LIFT INTO THE AREA. CANNOT RULE OUT A FEW STRONG
TO SEVERE STORMS OVER WESTERN PORTIONS OF THE AREA SATURDAY NIGHT IN
DEEP SHEAR/HIGHER CAPE ENVIRONMENT. STRONG TO SEVERE STORM THREAT
CONTINUES SUNDAY AS A COLD FRONT PUSHES INTO THE AREA. EXTENT OF
SEVERE THREAT WILL BE DEPENDENT OF HOW MUCH THE ATMOSPHERE CAN
RECOVER FROM ONGOING CONVECTION AND TIMING OF THE FRONT. WILL
CONTINUE TO KEEP A CLOSE EYE ON THIS. TEMPERATURES SUNDAY ARE
EXPECTED TO TOP OFF IN THE MIDDLE/UPPER 70S.
AFTER THIS...BEGINNING OF THE NEW WORK WEEK LOOKS COOLER/DRIER
BEHIND THE DEPARTING LOW/COLD FRONT. PLAN ON HIGHS MONDAY AND
TUESDAY IN THE UPPER 50S TO THE LOWER 60S.
SHOWER/THUNDERSTORM CHANCES SPREAD INTO THE AREA AGAIN BY WEDNESDAY
IN WARM AIR ADVECTION AHEAD OF A TROUGH PUSHING OUT OF THE PLAINS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1206 PM CDT THU MAY 14 2015
THE LIGHT RAIN HAS BEEN VERY SLOW TO ADVANCE EAST TODAY DUE TO THE
DRY AIR IN PLACE OVER WISCONSIN. THE 14.15Z HRRR INDICATES THIS
TREND WILL CONTINUE THROUGH THE AFTERNOON WITH THE LIGHT
RAIN/SPRINKLES NOT REACHING KLSE UNTIL THE MIDDLE OF THE
AFTERNOON. THERE IS ALSO A TREND IN THE HI-RES MESO MODELS THAT
THE ACTIVITY COMING UP OUT OF MISSOURI WILL BECOME THE MORE
DOMINANT AREA OF RAIN CAUSING A DRY SLOT TO DEVELOP NORTH OF IT
AND OVER THE AREA. SOME SUGGESTIONS IN THE REGIONAL RADAR DISPLAY
THAT THIS IS INDEED OCCURRING AND THAT IT WILL TAKE THE MORE
WIDESPREAD ACTIVITY OVER WESTERN IOWA TO SPREAD IN BEFORE THERE
WILL LIKELY BE ANY VISIBILITY RESTRICTIONS OCCURRING. HAVE THUS
PUSHED BACK THE TIMING OF MVFR VISIBILITY AT KLSE UNTIL EARLY THIS
EVENING BUT STILL SHOW IT BY LATE AFTERNOON AT KRST DUE MORE SO TO
SOME LIGHT FOG DEVELOPING AS THE LOW LEVELS CONTINUE TO SATURATE.
CEILINGS WILL ALSO CONTINUE TO COME DOWN WITH THIS SATURATION WITH
KRST EXPECTED TO GO TO IFR THIS AFTERNOON AND KLSE COMING DOWN TO
MVFR THIS EVENING. THE RAIN SHOULD END BY MID TO LATE EVENING WITH
BOTH SITES STAYING IFR/MVFR UNTIL FRIDAY MORNING AS THE WINDS
START TO PICK UP OUT OF THE NORTHWEST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS
AVIATION...04
AREA FORECAST DISCUSSION...CORRECTED AVIATION
NWS CHEYENNE WY
1204 PM MDT THU MAY 14 2015
.SHORT TERM...(TODAY THROUGH SATURDAY NIGHT)
ISSUED AT 300 AM MDT THU MAY 14 2015
FOG HAS FORMED OVER THE PAST FEW HOURS IN THE NORTH PLATTE VALLEY
AND ACROSS PORTIONS OF THE NEBRASKA PANHANDLE. WITH REALLY LIGHT
WINDS THE HRRR KEEPS LIFR CONDITIONS THRU 13Z SO INCLUDED SOME
PATCHY FOG INTO THE MID MORNING. OVERALL...SHOWER ACTIVITY WILL BE
QUITE A BIT LESS THIS AFTN COMPARED TO YESTERDAY. A SHORTWAVE
RIDGE WILL MOVE OVERHEAD THROUGH THE AFTN AND LOW LEVEL MOISTURE
IS NOT ALL THAT IMPRESSIVE. THE MODELS KEEP ISOLATED CONVECTION
CONFINED TO AREAS ALONG AND WEST OF THE LARAMIE RANGE THROUGH 00Z.
UPPER LEVEL DIVERGENCE WILL INCREASE AFTER 00Z AS A SHORTWAVE
EJECTS NORTHWARD ON THE EAST SIDE OF THE UPPER LOW OVER
CALIFORNIA. WITH GOOD MID LEVEL ISENTROPIC ASCENT AND SOME
ELEVATED CAPE...THIS IS ACTUALLY A SITUATION WHERE SHOWER AND TSTM
COVERAGE COULD BE GREATER INTO THE NIGHT...ESPECIALLY OVER THE
NORTHEASTERN HALF OF THE CWA. THUS...KEPT THE 30-40 POPS GOING
THROUGH EARLY FRI MORNING. SOUTHEASTERLY SFC WINDS WILL CONTINUE
TO ADVECT HIGHER DEWPOINTS INTO THE PLAINS THROUGH THE NIGHT.
THE MOST IMPACTING EVENT IN THE SHORT TERM IS STILL LOOKING LIKE
THE CHANCE OF SEVERE STORMS ACROSS THE NEBRASKA PANHANDLE ON FRI.
OVER THE PAST FEW DAYS THE MODELS HAVE BEEN CONSISTENT AT SHOWING
THE COMBINATION OF INSTABILITY (CAPE VALUES OF 1500-1750 J/KG) AND
DEEP LAYER SHEAR (40-45 KTS) TO SUPPORT SUPERCELLS ALONG AND NORTH
OF THE WARM FRONT. THE MAIN QUESTION WILL BE JUST WHERE THE SFC
LOW AND ASSOCIATED WARM FRONT ARE LOCATED BY MIDDAY. TEND TO
PREFER THE NAM AND ECMWF SOLNS THAT INDICATE EAST WINDS CONTINUING
ACROSS MUCH OF THE PANHANDLE THRU THE AFTN...AS OPPOSED TO THE GFS
THAT PUSHES WESTERLY WINDS AND DRIER DEWPOINTS ACROSS THE ENTIRE
PANHANDLE BY 00Z. OF COURSE WILL ALSO HAVE TO WATCH AND SEE
WHETHER THE SFC LOW IS FURTHER WEST TOWARD THE LARAMIE RANGE AS
THIS WOULD PUSH THE SEVERE THREAT INTO SOUTHEAST WY. WHILE LARGE
HAIL WOULD LIKELY BE THE PRIMARY THREAT...THE LOW LEVEL SHEAR
PARAMETERS DO SHOW THE POTENTIAL FOR SOME WEAK TORNADOES
ESPECIALLY ALONG AND JUST NORTH OF THE WARM FRONT WHERE WINDS WILL
BE BACKED THE MOST. NAM HODOGRAPHS ARE PRETTY IMPRESSIVE WITH 0-3
KM HELICITY OF 250-300. LCL HEIGHTS ARE RATHER LOW ALSO. THE DAY 2
SPC OUTLOOK HAS NOT CHANGED MUCH WITH MOST OF THE PANHANDLE IN A
SLIGHT RISK...AND THE ENHANCED RISK IS JUST OFF TO THE EAST INTO
NORTH PLATTES CWA. IT WILL DRY OUT QUICKLY BY FRI EVENING AS THE
SFC LOW AND WARM FRONT PUSH NORTHWARD INTO THE DAKOTAS. WITH QUITE
A BIT LESS LOW LEVEL MOISTURE AND INSTABILITY TO WORK WITH ON
SAT...CONVECTION WILL BE WEAKER AND LESS WIDESPREAD. THE UPPER
LEVEL SYSTEM WILL MOVE INTO THE CENTRAL PLAINS BY SAT NIGHT WITH A
COLD FRONT PUSHING ACROSS THE REGION.
.LONG TERM...(SUNDAY THROUGH WEDNESDAY)
ISSUED AT 300 AM MDT THU MAY 14 2015
AN ACTIVE WEATHER PATTERN SHOULD PERSIST WITH LARGE SCALE
TROUGHING REMAINING INTACT OVER THE WESTERN CONUS. SOME LINGERING
SHOWERS AND TSTMS CAN BE EXPECTED ON SUN/SUN NIGHT AS A STRONG
/NEGATIVELY-TILTED MID-LEVEL SHORTWAVE LIFTS NORTHEAST INTO THE
DAKOTAS. THE PROJECTED TRACK OF THIS SYSTEM AND H7-H3 PROGS FROM
THE GFS/ECMWF SUGGEST THAT AREAS ALONG THE I80 CORRIDOR BETWEEN
CYS AND SNY WOULD SEE LESS PCPN WITH A POTENTIAL DRY SLOT ALOFT. A
TRANSITORY RIDGE WILL TEMPORARILY QUIET THINGS DOWN ON MON WITH
WEAK SUBSIDENCE AND SOME DRYING IN THE MID LEVELS. THE GFS HAS
COME INTO LINE WITH THE ECMWF ON TUE SHOWING WIDESPREAD LOW LEVEL
UPSLOPE DEVELOPING EAST OF THE LARAMIE RANGE AHEAD OF THE NEXT
SYSTEM LIFTING INTO THE DESERT SW. THE LATEST SUITE OF MEDIUM
RANGE MODEL GUIDANCE SHOWS QPF VALUES UP TO AN EXCEEDING ONE INCH
BETWEEN TUE NIGHT AND WED. THIS MAKES SENSE WITH LOW LEVEL FORCING
BENEATH INCREASINGLY DIFFLUENT FLOW ALOFT AND A COUPLED H25 JET.
THE EURO IS CONSIDERABLY COLDER THAN THE GFS...SHOWING H7 TEMPS
FALLING TO BETWEEN -2 AND -4 DEG C BY 12Z WED. WHILE WARM
ADVECTION IN LOW LEVEL EASTERLY/UPSLOPE FLOW MAKES THIS
QUESTIONABLE AT THIS RANGE...WOULD NOT BE ENTIRELY SURPRISED TO
SEE PCPN CHANGE TO SNOW AT SOME POINT DURING THIS EVENT...AT LEAST
FOR HIGHER ELEVATIONS. POTENTIAL FOR CONVECTION WILL EXIST
VIRTUALLY EVERY DAY WITH SLIGHTLY NEGATIVE LIFTED INDEX VALUES
EACH AFTN THROUGH WED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1159 AM MDT THU MAY 14 2015
VFR CONDITIONS WILL PREVAIL AT ALL TERMINALS THIS AFTERNOON AND
EVENING. WIDELY SCATTERED SHOWERS/TSTORMS WILL DEVELOP AFTER 20Z
ACROSS SOUTHEAST WY...WITH MORE ISOLATED OVER FAR WESTERN NE AFTER
00Z. CONVECTION MAY BE ACCOMPANIED BY GUSTY AND ERRATIC WINDS AND
LOCALIZED MVFR CIGS/VSBYS. MVFR-IFR CIGS AND MVFR VSBYS SHOULD
BECOME MORE WIDESPREAD OVER WESTERN NE AND FAR SOUTHEAST WY AFTER
09Z.
&&
.FIRE WEATHER...
ISSUED AT 300 AM MDT THU MAY 14 2015
NO FIRE WEATHER CONCERNS THROUGH THE WEEKEND. TODAY WILL BE THE
WARMEST DAY WITH MINIMUM AFTERNOON HUMIDITY VALUES FALLING TO
25-30 PERCENT AT SOME LOCATIONS. SHOWERS AND THUNDERSTORMS WILL
BECOME MORE WIDESPREAD BY LATE TONIGHT INTO FRIDAY AND COOLER
TEMPERATURES WILL OCCUR INTO THE WEEKEND. FUELS ARE ALSO IN FULL
GREEN UP AFTER THE RECENT WET PERIOD.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...ZF
LONG TERM...CLH
AVIATION...MJ
FIRE WEATHER...ZF