Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/18/15
AREA FORECAST DISCUSSION
NWS SAN FRANCISCO BAY AREA
515 PM PDT SUN MAY 17 2015
.SYNOPSIS...BELOW NORMAL TEMPERATURES WITH MOSTLY DRY CONDITIONS
ARE EXPECTED TO CONTINUE THROUGH FRIDAY. THERE COULD BE A FEW
SHOWERS OVER INTERIOR MOUNTAINS LATE TODAY AND AGAIN THURSDAY AS
WEAK LOW PRESSURE DISTURBANCES MOVE ONSHORE. HIGH PRESSURE AND
WARMER CONDITIONS ARE EXPECTED OVER THE MEMORIAL DAY WEEKEND.
&&
.DISCUSSION...AS OF 02:16 PM PDT SUNDAY...DESPITE MID AND HIGH
CLOUDS...MANAGING TO GET A FEW CONVECTIVE BUILDUPS OVER INTERIOR
MOUNTAINS WHERE SUNSHINE IS MORE PREVALENT. HRRR MODEL CAPTURING
THE CONVECTION OVER NORTHEAST SANTA CLARA COUNTY PRETTY WELL AND
SHOULD PERSIST FOR A FEW MORE HOURS...THEN SHIFT EAST AND DECREASE
THIS EVENING. MODEL ALSO SHOWS ACTIVITY FORMING OVER EASTERN SAN
BENITO COUNTY AND PARTS OF MONTEREY COUNTY...BUT THICKER CLOUDS HAVE
LIMITED CONVECTION. WOULD EXPECT SOME BUILDUPS AND POSSIBLY A
SHOWER IN THIS AREA AS WELL LATER THIS AFTERNOON AS SOME BREAKS IN
MID CLOUDS EXPECTED. OTHER AREA TO WATCH IS EXTREME NORTH BAY OVER
ELEVATED TERRAIN...BUT NOT EXPECTING MORE THAN A FEW CUMULUS
BUILDUPS.
WELL MIXED MARINE LAYER PERSISTS AND IS AT LEAST 3000 FEET DEEP
THIS AFTERNOON NEAR THE COAST AND BAY AREA. TEMPERATURES MOSTLY IN
THE 60S AND NOT MUCH CHANGE EXPECTED IN THE CURRENT COOL
TEMPERATURE REGIME THROUGH AT LEAST THURSDAY. MARINE LAYER SHOULD
REMAIN DEEP THROUGH THE WEEK AS WELL WITH A LINGERING TROF ALONG
THE COAST. SERIES OF SHORT WAVES WILL REINFORCE THIS TROF
THROUGHOUT THE WEEK WITH ONE WAVE MOVING ACROSS THE AREA MONDAY
AND ANOTHER ONE WEDNESDAY AND THURSDAY. STRONGEST FEATURE LOOKS TO
ARRIVE THURSDAY AND PUSHES TOWARD SOUTHERN CALIFORNIA.
MAIN IMPACT ON CENTRAL CALIFORNIA COAST WEATHER WILL BE PERSISTENT
LOW CLOUDS ESPECIALLY NEAR THE COAST...COOL TEMPERATURES...AND MOSTLY
DRY WEATHER. SHOWER THREAT SHOULD BE REDUCED MONDAY AND TUESDAY AS
DYNAMICS AND MOISTURE SHIFT FURTHER INLAND. OUTSIDE CHANCE OF A
SHOWER EACH AFTERNOON IN EXTREME NORTH BAY GIVEN INSTABILITY OVER
TERRAIN. THURSDAY BRINGS A BETTER RISK FOR SHOWERS OVER INTERIOR
AS THE STRONGEST WAVE IN THE SERIES BRINGS CYCLONIC CURVATURE AND
SOME ADDED LIFT TO THE AREA.
RIDGE BUILDS INTO COAST OVER THE WEEKEND...SO DRYING AND WARMING
TREND EXPECTED FROM FRIDAY INTO SUNDAY.
&&
.AVIATION...AS OF 5:15 PM PDT SUNDAY... TROUGH SITUATED JUST
OFFSHORE OF THE CALIFORNIA COASTLINE THIS EVENING. SYSTEM WILL
SWEEP INLAND AND CLOUD COVERAGE EARLY THIS EVENING. EXPECT
PREDOMINATELY MVFR CONDITIONS WITH BASES 1800-2500 FT. BRIEF
PERIODS OF VFR FEW/SCT CONDS POSBL FROM 00-03Z OVER MONTEREY BAY
TERMINALS AND FURTHER INLAND AROUND THE SF BAY. ONSHORE FLOW WILL
PREVAIL THROUGH THE NIGHT WITH SPEEDS UP TO 15 KT AND GUSTS AOA 20
KT.
VICINITY OF KSFO... MVFR WITH ONSHORE FLOW THROUGH THE NEXT 24
HOURS. VFR POSBL IN EARLY AFTERNOON MON.
KSFO BRIDGE APPROACH... SIMILAR TO KSFO.
MONTEREY BAY AREA TERMINALS... VFR THROUGH THE NEXT FEW HOURS THEN
MVFR WITH BASES 1500-2500FT THROUGH THE NIGHT. WEAK ONSHORE FLOW.
VFR MIX OUT AOA 21Z MON.
&&
.MARINE...AS OF 05:08 PM PDT SUNDAY...RELATIVELY LIGHT
NORTHWESTERLY WINDS WILL PREVAIL OVER THE COASTAL WATERS THROUGH
MIDWEEK. WINDS ARE FORECAST TO INCREASE LATE IN THE WEEK.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.TNGT...NONE.
$$
PUBLIC FORECAST: KBB
AVIATION: DRP
MARINE: DYKEMA
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AREA FORECAST DISCUSSION
NWS EUREKA CA
335 PM PDT SAT MAY 16 2015
.SYNOPSIS...A SERIES OF UPPER LOWS WILL BRING SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS TO MAINLY THE INTERIOR EACH AFTERNOON
THROUGH MID WEEK. OTHERWISE DRY WEATHER CONDITIONS WITH BELOW
NORMAL TEMPERATURES WILL CONTINUE TO PREVAIL THROUGH NEXT WEEK.
&&
.DISCUSSION...AN UPPER LOW WILL APPROACH THE NORTH COAST TONIGHT
INTO SUNDAY MORNING. PROFILES ARE NOT LOOKING ALL THAT IMPRESSIVE
FOR STORMS THIS EVENING WITH LIFTED INDICES NEAR -1C...CAPE
AROUND 300J/KG AND EQUILIBRIUM LEVELS NEAR 22KFT. WILL GO AHEAD
AND TOSS ISOLATED SHOWERS AND STORMS INTO THE FORECAST OVER THE
YOLLA BOLLYS AND TRINITY MOUNTAINS FOR EARLY THIS EVENING IN THE
OUTSIDE CHANCE WE DO GET A FEW STRIKES. THIS WILL ALSO BLEND WITH
NEIGHBORING CWA`S AND SPC`S GENERAL TSTM OUTLOOK.
HIGH RESOLUTION MODELS SHOW THE ACTIVITY DYING DOWN THIS EVENING
AFTER LOSS OF PEAK HEATING...THEN SPIKING UP AGAIN LATE TONIGHT
INTO SUNDAY MORNING. CONFIDENCE IS NOT HIGH THIS WILL ACTUALLY
OCCUR DUE TO THE RELATIVELY LOW CAPE AND WEAK FORCING FROM THE
APPROACHING LOW PRESSURE SYSTEM ALOFT. THE POSSIBILITY DOES EXIST
WE MAY SEE STORMS REDEVELOP IN THE EARLY MORNING HOURS...SO WILL
GO AHEAD AND ADD THEM TO THE FORECAST. IF IT DOES NOT HAPPEN...OH
WELL.
SUNDAY IS STILL LOOKING BETTER FOR INTERIOR CONVECTION AS THE
UPPER LOW APPROACHES CAPE MENDO. THE AREA OF GREATEST INSTABILITY
AND PRECIP SHOULD SHIFT INTO WESTERN PORTIONS OF HUMBOLDT AND DEL
NORTE COUNTIES WITH PERHAPS SOME ACTIVITY IN THE NE PORTION OF
MENDOCINO COUNTY. CONFIDENCE THUNDERSTORMS WILL ADVECT OUT TO THE
COAST IS NOT HIGH DUE TO WEAK SSE FLOW ALOFT TO PROPEL THE
STORMS. ANY STORMS THAT DO MANAGE TO SPROUT UP WITH HEATING WILL
PROBABLY QUICKLY COLLAPSE. THE GFS AND ECMWF HAVE BEEN TOO BROAD
BRUSH WITH THE PRECIP SO WILL CONTINUE TO USE THE NAM12 AS THE
PRIMARY GUIDANCE. THE HIRES-NMM AND HRRR HAVE BEEN MODELING THE
CONVECTION FAIRLY GOOD AS WELL. THUS THE BROAD BRUSH GFS AND ECMWF
FIELDS HAVE BEEN SCALED BACK. SHOWER AND ISOLATED STORM CHANCES
WILL LIKELY PERSIST ON MONDAY AS THE UPPER LOW MEANDERS SOUTHWARD
OVER CENTRAL CALIFORNIA. A BROAD LOW PRESSURE SYSTEM ALOFT WILL
REMAIN OVER THE REGION ON TUE. CONVECTIVE PARAMETERS WERE NOT
LOOKING AS FAVORABLE FOR STORMS ON TUE. IT IS STILL 3 DAYS OUT AND
A LOT WILL CHANGE BETWEEN NOW AND THEN. SO WILL NOT MAKE TOO MANY
CHANGES HERE.
.LONG-TERM...WED THROUGH SAT...A BROAD AND COMPLEX LOW PRESSURE
SYSTEM ALOFT WILL CONTINUE TO BRING A THREAT OF SHOWERS AND
PERHAPS ISOLATED T-STORMS TO MAINLY THE INTERIOR THROUGH THU.
MORE STABLE CONDITIONS MAY DEVELOP FRI INTO SAT AS A RIDGE ALOFT
BUILDS CLOSER TO THE COAST. THE MODELS WERE NOT EXACTLY IN GREAT
AGREEMENT HERE. THE GFS BUILDS A FLAT RIDGE OVER THE WEST COAST WHILE
THE ECMWF HAS ANOTHER UPPER LOW DIVING SOUTHWARD. THE GEM WAS IN
BETWEEN WITH BROAD CYCLONICALLY CURVED NORTH FLOW OVER THE AREA.
CONSIDERING THE PERSISTENT LARGE SCALE TROUGH PATTERN AND THE
DISCONGRUITY IN THE MODEL DATA...WILL MAINTAIN A SLIGHT CHANCE OF
SHOWERS IN THE INTERIOR FRI THROUGH SAT.
&&
.AVIATION...VFR CEILING HAVE PERSISTED ALONG THE COASTAL AIR
TERMINALS MOST OF THE DAY...ALTHOUGH CLOUDS MAY CONTINUE TO NUDGE
SLIGHTLY WEST INTO ACV AND CEC THROUGH THE AFTERNOON. CEILINGS
SHOULD BUILD BACK INTO COASTAL AREAS DURING THE LATE AFTERNOON
/EVENING...THEN REMAIN MVFR THOUGH THE LATE MORNING HOURS ON SUNDAY.
INLAND CONDITIONS SHOULD REMAIN VFR THROUGH THE NEXT TAF CYCLE.
&&
.MARINE...GENERALLY LIGHT NORTHERLIES AND SMALL SHORT PERIOD SEAS
ARE BEING OBSERVED ACROSS ALL WATERS. THESE CONDITIONS WILL REMAIN
GENERALLY STEADY STATE THROUGH THE MIDDLE OF THE WEEK...AS WINDS ARE
EXPECTED TO REMAIN IN THE MODERATE TO FRESH RANGE. A REINFORCING MID
PERIOD WESTERLY SWELL WILL BUILD INTO THE WATERS OVER THE WEEKEND
BUT IS NOT EXPECTED TO BE PARTICULARLY LARGE...WHILE A SMALL
SOUTHERLY SWELL WILL CONTINUE TO MOVE THROUGH AS WELL.
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
NORTHWEST CALIFORNIA COASTAL WATERS...NONE.
&&
$$
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AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
540 PM MDT SUN MAY 17 2015
.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 331 PM MDT SUN MAY 17 2015
IN SPITE OF BUILDING HIGH PRESSURE OVER UTAH AND WARMING TEMPS
ALOFT...AFTERNOON CAPE VALUES OF 250-500 J/KG SUGGEST CONVECTIVE
SHOWERS WITH SOME THUNDERSTORMS. MOISTURE TRANSPORT DOES EXIST
FROM THE UINTA MOUNTAINS TOWARD VAIL AND INDEPENDENCE PASS
REGION...AND SHOWERS/STORMS WILL BE CONCENTRATED ACROSS THIS AREA.
CONVECTIVE POTENTIAL EXIST ELSEWHERE BUT NOT AS NUMEROUS OVER SW
COLORADO...AND MOSTLY DRY OVER SE UTAH.
CONVECTIVE POTENTIAL MOSTLY DIMINISHES WITH SUNSET. NOT SO SURE
THIS WILL BE THE CASE ACROSS PARTS OF ERN UTAH AS MOISTURE
TRANSPORT INCREASES OVERNIGHT...THE HRRR SHOW CONVECTIVE SHOWERS
PERSISTING PAST MIDNIGHT AND TRACKING OVER THE UINTA
BASIN/MOUNTAINS. BY DAYBREAK...HIGH CLOUDS WILL BE SPREADING FROM
THE SOUTH AS THE NEXT CALIFORNIA UPPER LOW ADVECTS MOISTURE
TOWARDS THE FOUR CORNERS REGION.
THE PACIFIC WAVE TRAIN CONTINUES MONDAY AS THE NEXT STORM SYSTEM
MOVES SLOWLY ONSHORE...ITS CENTER SETTLING OVER CALIFORNIA/S SAN
JOAQUIN VALLEY LATE IN THE AFTERNOON. SOUTHERLY FLOW AHEAD OF THE
TROUGH WILL CAUSE MOISTURE LEVELS TO RISE ONCE AGAIN AS GULF
MOISTURE IS TAPPED. GFS AND NAM BOTH INDICATED PRECIPITABLE WATER
VALUES RISING TO NEAR 0.6 OF AN INCH. MEANWHILE...AN 110 KT JET
ROTATES THROUGH THE BASE OF THE TROUGH GIVING IT A SLIGHTLY
NEGATIVE TILT. THE NOSE OF THE JET PUSHES TOWARD THE FOUR CORNERS
WHICH WILL PROVIDE CONSIDERABLE DIVERGENCE TO ADD TO THE DIFFLUENT
FLOW ALOFT. THE DYNAMIC LIFT JUST DESCRIBED COMBINED WITH DAYTIME
HEATING WILL GENERATE SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS FAVORING THE MOUNTAINS. AS MENTIONED IN THE PREVIOUS
DISCUSSION...ARRIVING MOISTURE WILL BE HIGH BASED ACCORDING TO
AREA TIME SECTIONS SO EXPECT MAIN STORM THREAT...ASIDE FROM
LIGHTNING...WILL BE STRONG AND GUSTY OUTFLOW WINDS. WAA ADVECTION
WILL CAUSE TEMPERATURES TO CLIMB CLOSER TO SEASONAL NORMS...
THOUGH EXPECT CLOUDS AND SHOWERS WILL LIMIT HIGHS. THEREFORE...
NUDGED MONDAY/S HIGHS TOWARD COOLER MAV GUIDANCE.
MONDAY NIGHT WILL REMAIN ACTIVE AS THE PACIFIC SYSTEM MOVES OVER
SOUTHERN NEVADA DURING THE NIGHT. DIFFLUENT/DIVERGENT FORCING
REMAINS IN PLACE WHILE MOISTURE CONTINUES TO STREAM INTO THE AREA
FROM THE SOUTH. AS A RESULT...WILL CONTINUE WITH LIKELY POPS IN
THE MOUNTAINS WITH CHANCE POPS ACROSS THE VALLEYS. COLDER AIR
BEGINS TO ADVECT OVER THE REGION DURING THE NIGHT CAUSING SNOW
LEVELS TO LOWER TO AROUND 9000 TO 9500 FEET. EXPECT ACCUMULATING
SNOW FOR AREAS ABOVE 10000 FEET WITH AMOUNTS OF UP TO 8 INCHES
POSSIBLE ABOVE THE TIMBERLINE. MODELS SUGGEST AMOUNTS OF 12 INCHES
OR MORE BUT APPEARS CONVECTIVE PARAMETERIZATION MAY BE A BIT
OVERDONE AS LAPSE RATES ONLY MODERATELY UNSTABLE. IMPACTS TO
ROADWAYS OVER THE HIGH PASSES PROBABLY NEGLIGIBLE WITH MOST SNOW
MELTING ON CONTACT SO WILL HOLD OFF ISSUING HILITES. CLOUDS...
SHOWERS AND WAA WILL YIELD MILDER OVERNIGHT LOWS AS PREVIOUSLY
FORECAST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 331 PM MDT SUN MAY 17 2015
COOL AND UNSETTLED CONDITIONS WILL CONTINUE TUESDAY AS THE
PACIFIC STORM MOVES OVER THE REGION. SNOW LEVELS WILL RISE WITH
DAYTIME WARMING...ESPECIALLY SOUTH...WHICH WILL INHIBIT ANY
ADDITIONAL ACCUMULATIONS BELOW 10000 FEET. CONDITIONS IMPROVE
TUESDAY NIGHT AS A TRANSIENT SHORTWAVE RIDGE BUILDS OVER THE AREA.
ANOTHER LOW DEVELOPS OVER THE EASTERN PACIFIC AT MIDWEEK BUT STAYS
QUASI-STATIONARY UNTIL THURSDAY NIGHT. A DRIER SOUTHWEST FLOW
WILL MOVE OVER THE FORECAST AREA AHEAD OF THIS SYSTEM LIMITING
MOIST CONVECTION TO THE MOUNTAIN AREAS DURING THE AFTERNOON AND
EVENING WEDNESDAY AND THURSDAY. TEMPERATURES WILL RECOVER DURING
THIS PERIOD REACHING NEAR NORMAL LEVELS THURSDAY AFTERNOON.
THE PACIFIC SYSTEM THEN FOLLOWS THE WELL BEATEN PATH PREVIOUS
STORMS HAVE TAKEN OVER THE PAST COUPLE OF WEEKS...TRACKING OVER
EASTERN UTAH AND WESTERN COLORADO FRIDAY AND SATURDAY.
CONSEQUENTLY...LOOK FOR AN UPTICK IN SHOWER AND THUNDERSTORM
ACTIVITY ONCE AGAIN ALONG WITH COOLER THAN NORMAL TEMPERATURES.
CONDITIONS ON SUNDAY LESS CERTAIN AS LATEST ECMWF DRIVES A
SHORTWAVE TROUGH ACROSS THE REGION FROM THE NORTHWEST WHILE GFS
FAVORS A TRANSITORY RIDGE. BOTH SOLUTIONS POINT TO A CONTINUATION
OF UNSETTLED CONDITIONS AS MOISTURE WILL LINGER IN EITHER CASE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 538 PM MDT SUN MAY 17 2015
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL LINGER THROUGH
03Z BEFORE ENDING FOR THE NIGHT. EXPECT BRIEF MVFR CIGS IN THE
VCNTY OF SHOWERS...WITH KASE AND KEGE MOST LIKELY TO BE IMPACTED
THIS EVENING. VFR CONDS THEN EXPECTED THROUGH MIDDAY
MONDAY...BEFORE ANOTHER SURGE OF MOISTURE MOVES IN. THIS WILL
BRING ANOTHER ROUND OF WIDESPREAD SHOWERS LATE MONDAY AFTERNOON
AND EVENING...WITH CIGS DROPPING AND MOUNTAINS BECOMING OBSCURED.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...PF/NL
LONG TERM...NL
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1147 PM MDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 543 PM MDT FRI MAY 15 2015
QUICK UPDATE TO BOOST POPS ACROSS MUCH OF THE FORECAST AREA FOR
THE NEXT SEVERAL HOURS. LATEST HRRR AND 18Z RUNS A LITTLE MORE
AGGRESSIVE OVERNIGHT AND WILL TREND POPS IN THIS DIRECTION. MINOR
WIGGLES OR WAVES IN THE FLOW WILL CONTINUE TO SPARK AREAS OF
SHOWERS WITH PERIODS OF NULL WEATHER ALSO EXPECTED THROUGH THE
OVERNIGHT HOURS.
&&
.SHORT TERM...(TONIGHT THROUGH SATURDAY NIGHT)
ISSUED AT 352 PM MDT FRI MAY 15 2015
THE LOW PRESSURE SYSTEM OVER THE GREAT BASIN WILL VERY GRADUALLY
SHIFT TO THE NORTHEAST TONIGHT AND CENTER ITS MAIN CORE OVER
NORTHERN UTAH AT 500MB BY THE EARLY MORNING HOURS...WITH A WEAK
CENTER OF CIRCULATION NEAR THE 4 CORNERS EMBEDDED IN THE GENERAL
PATTERN AT THIS SAME TIME. THIS SYSTEM IS BROADLY ORGANIZED AND
BECAUSE OF THAT...POCKETS OF NO SIGNIFICANT WEATHER AND POCKETS OF
MODERATE TO HEAVY PRECIPITATION WILL OCCUR. CURRENT SATELLITE
IMAGERY INDICATES AN AREA OF GOOD UPLIFT OVER THE PAGOSA
SPRINGS/WOLF CREEK REGION. NE UTAH AND NW COLORADO ARE
TRANSITIONING INTO A MORE STABLE AREA SO WILL SEE A BREAK FOR
ABOUT 6 TO 12 HOURS THIS EVENING WITH THE OCCASIONAL ISOLATED SHOWER
ABLE TO DEVELOP. COLD AIR IS ADVECTING INTO THE REGION WITH SNOW
LEVEL EXPECTED TO DROP THROUGHOUT THE EVENING. GOOD VERTICAL
VELOCITY FORECAST FOR THE FOUR CORNERS TONIGHT BETWEEN 5PM THIS
EVENING THROUGH TOMORROW MORNING SO WILL EXPECT PRECIPITATION TO
PICK UP THIS EVENING IN THIS AREA WITH EFFICIENT PRECIPITATION
RATES...AND SNOW DOWN TO 7500 FEET AND FALLING BY MIDNIGHT.
ANOMALOUSLY STRONG CLOSED LOW EJECTS NORTHEAST ACROSS THE WESTERN
SLOPE ON SATURDAY. THE COLDEST AIR AND DYNAMICAL LIFT OCCURS WITH
THIS FEATURE. THE BEST QPF WILL BE FOCUSED OVER THE SAN JUAN
MOUNTAINS...ALTHOUGH THE WRN CO MOUNTAINS WILL GET A FAIR AMOUNT
TONIGHT AND SATURDAY MORNING.
A SECONDARY SHORT WAVE ROTATES INTO WRN COLORADO SATURDAY NIGHT.
ALTHOUGH THIS SHORT WAVE ARRIVES FROM THE NORTHWEST...MODEL DATA
SHOWS BRIEF MID LEVEL COLD ADVECTION SATURDAY EVENING (BUT NOT ANY
COLDER THAN THE MAIN COLD CORE TONIGHT/SATURDAY). SNOW LEVELS
WILL NOT FALL ANY LOWER THAN OCCURS SATURDAY MORNING...POSSIBLY
BECOME SLIGHTER HIGHER GIVEN SLIGHTLY WARMER AIR AND LOWER QPF
RATES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 352 PM MDT FRI MAY 15 2015
SOME SHORT LIVED TERRAIN DRIVEN CONVECTIVE SHOWERS WILL OCCUR
SUNDAY AFTERNOON...OTHERWISE A BRIEF RESPITE FROM THE RAIN OR
SNOW. BUT THE NEXT PACIFIC CLOSED LOW BARRELS INTO CALIFORNIA ON
MONDAY. A NEGATIVELY TILTED SHORT WAVE EJECTS ACROSS THE FORECAST
AREA MONDAY NIGHT AND TUESDAY. LIKE THE CURRENT WEATHER
SYSTEM...THIS GENERATES ANOTHER HEALTHY DOSE OF SHOWERS/STORMS
WITH A FAIR AMOUNT OF RAINFALL. THIS WILL BE A WARMER SYSTEM AND
SNOW WILL BE LIMITED TO ABOVE TIMBERLINE...MAYBE SNOW LEVELS
LOWERING TO THE MOUNTAIN PASSES.
DRIER SOUTHWEST FLOW PREVAILS OVER THE FOUR CORNERS REGION FOR THE
WEDNESDAY THROUGH FRIDAY TIME FRAME. SOME DIURNAL CONVECTIVE
SHOWERS MAY STILL FORM OVER THE MOUNTAIN AREAS...BUT THESE WILL
NOT BE LONG LASTING AND PRODUCE LIGHT RAIN AMOUNTS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1126 PM MDT FRI MAY 15 2015
THIS VERY WET SYSTEM WILL CONTINUE TO IMPACT FLIGHT OPERATIONS
ACROSS EASTERN UTAH AND WESTERN COLORADO OVER THE NEXT 24 HOURS.
THREATS WILL BE LOWERED FLIGHT CRITERIA AND OCCASIONAL LIGHTNING
DURING THE AFTERNOON AND EVENING TIME PERIODS FROM PASSING
THUNDERSTORMS. MOST VALLEY LOCATIONS WILL BE ABLE TO SUSTAIN VFR
CONDITIONS BUT TEMPORARY MVFR WILL BE POSSIBLE IN PASSING SHOWERS.
AT THE MOUNTAIN TERMINALS SITES INCLUDING KASE...KTEX AND POSSIBLY
KEGE...IFR CONDITIONS WILL ALSO BE POSSIBLE WITH REDUCTION TO BOTH
VSBY AND CIGS COMING FROM SNOWFALL THROUGH 17/06Z.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL NOON MDT SATURDAY FOR COZ009-010-
012-018-019.
WINTER STORM WARNING UNTIL 9 AM MDT SUNDAY FOR COZ009-010-012-
018-019.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT SATURDAY NIGHT FOR
COZ017.
WINTER WEATHER ADVISORY UNTIL 9 AM MDT SUNDAY FOR COZ004-013.
UT...WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT SATURDAY NIGHT FOR
UTZ028.
&&
$$
UPDATE...JDC
SHORT TERM...JAM/PF
LONG TERM...PF
AVIATION...JDC
AREA FORECAST DISCUSSION
NWS NEW YORK NY
347 PM EDT SAT MAY 16 2015
.SYNOPSIS...
A WARM FRONT WILL BE SLOW TO PUSH NORTH OF THE AREA THROUGH THIS
EVENING...WHILE A TROUGH OF LOW PRESSURE APPROACHES FROM THE
WEST...LINGERING NEARBY ON SUNDAY. A BACKDOOR COLD FRONT MOVES
THROUGH SUNDAY NIGHT. THE FRONT STALLS JUST SOUTHWEST OF THE
REGION ON MONDAY WITH HIGH PRESSURE BUILDING IN FROM THE
NORTHEAST. THIS FRONT WILL LIFT THROUGH AS A WARM FRONT TUESDAY
MORNING...FOLLOWED BY A COLD FRONT ON TUESDAY. HIGH PRESSURE IS
THEN IN CONTROL INTO NEXT WEEKEND...WITH THE EXCEPTION OF A WEAK
COLD FRONTAL PASSAGE ON FRIDAY
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
WARM FRONT LOCATED NEAR THE NYC METRO AS OF 19Z WILL CONTINUE TO
SLOWLY LIFT NE THROUGH THE AREA THIS EVENING. IT IS POSSIBLE THE
WARM FRONT DOES NOT COMPLETELY CLEAR FAR EASTERN ZONES UNTIL TONIGHT.
DESTABILIZATION UNDERWAY WEST OF THE HUDSON RIVER WITH ENOUGH
BREAKS IN THE CLOUDS FOR SUNSHINE TO WARM TEMPERATURES INTO THE
UPPER 70S AND LOWER 80S...WITH DEW POINTS IN THE UPPER 50S AND
LOWER 60S.
LATEST HRRR AS WELL AS ITS PREVIOUS SEVERAL RUNS HAVE A BAND OF
CONVECTION MOVING INTO THE LOWER HUDSON VALLEY AROUND 21-22Z. THIS
HAS SUPPORT FROM THE 12Z NAM AND 15Z RAP AS WELL AS THE 12Z SPC
WRF. SURFACE BASED INSTABILITY DIFFERS SOMEWHAT AMONG THE MODEL
GUIDANCE...BUT HAVE ENOUGH CONFIDENCE THAT 800 TO 1200 J/KG OF
SURFACE BASED CAPE WILL BE AVAILABLE ACROSS THE FAR NW INTERIOR
FOR CONVECTION TO TAP INTO LATE THIS AFTERNOON AS IT MOVES INTO
THE AREA. MODERATELY STRONG WESTERLY LOW-MID LEVEL FLOW SUPPORTS
UNIDIRECTIONAL SHEAR AROUND 30 KT. A MARGINAL RISK OF SEVERE
WEATHER PER SPC CONTINUES WEST OF THE HUDSON RIVER WHERE GREATEST
SURFACE BASED INSTABILITY WILL RESIDE. THE THREAT IS FOR A STORM
OR TWO TO CONTAIN DAMAGING WIND GUSTS.
THE BAND OF CONVECTION WILL CONTINUE MOVING EAST THIS EVENING...
REACHING THE NYC METRO AROUND 00Z. WITH MARITIME INFLUENCE ALONG AND
EAST IF THE HUDSON RIVER...INSTABILITY WILL BE ELEVATED WITH
LITTLE TO NO CHANCE FOR ANY SEVERE CONVECTION. CONVECTION SHOULD
ELEVATED AND BEGIN TO WEAK AS IT MOVES OVER LONG ISLAND AND
SOUTHERN CT. HOWEVER...MULTIPLE SHORT WAVES ALOFT ROUNDING THE TOP
OF THE RIDGE MAY HELP TO SUSTAIN THE CONVECTION AS IT WORKS ITS
WAY EAST. CURRENT FORECAST PACKAGE INDICATED LIKELY SHOWERS/STORMS
WEST OF THE HUDSON AND LIKELY SHOWERS WITH A CHANCE OF
THUNDERSTORMS EAST OF THE HUDSON.
HIGH PW VALUES WILL ALSO MEAN THERE IS THE POTENTIAL FOR BRIEF HEAVY
DOWNPOURS IN ANY STORM. MINOR URBAN FLOODING IS A POSSIBILITY.
CONVECTION DISSIPATES BY MIDNIGHT WITH SHOWERS LINGERING THROUGH
DAYBREAK SUNDAY. TEMPERATURES TONIGHT WILL BE MILD IN THE 60S.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
DEEP UPPER LEVEL RIDGE BUILDS ACROSS THE EASTERN US ON SUNDAY. SURFACE
TROUGH LINGERS ACROSS THE AREA. WITH A DRIER AIR MASS IN
PLACE...EXPECTING MORE IN THE WAY OF SUNSHINE. THIS SHOULD ALLOW
TEMPERATURES TO WARM INTO THE LOWER AND MIDDLE 80S INLAND AND IN
THE NYC METRO...AND THE UPPER 70S CLOSER TO THE COAST. INSTABILITY
WILL BE ON THE INCREASE DURING THE DAY FROM THE CITY NORTH AND
WEST. AFTERNOON SEA BREEZES FURTHER EAST WILL LIMIT INSTABILITY.
LOW CHANCE POPS FORECAST ACROSS WESTERN ZONES IN THE BETTER
INSTABILITY AND WITH SURFACE TROUGH IN THE VICINITY. HOWEVER...THE
UPPER LEVEL RIDGE SHOULD LIMIT CONVECTIVE DEVELOPMENT. IF A STORM
DEVELOPS SUNDAY...IT MAY BE SLOW MOVING WITH WEAK LOW AND MIDDLE
LEVEL FLOW.
HIGH PRESSURE WILL BEGIN TO BUILD SW ACROSS THE AREA SUNDAY NIGHT
SENDING A BACK DOOR FRONT THROUGH. MODELS DIFFER IN THE TIMING OF
THE FRONT PASSAGE. CURRENT THINKING IS THAT THE FRONT WILL BEGIN
MOVING SOUTH ACROSS THE AREA SUNDAY EVENING. WITH THIS FRONT...AN
ISOLATED SHOWER OR STORM CANNOT BE RULED OUT. AS THE LOW LEVELS
COOL AND MOISTEN BEHIND THE FRONT...SOME FOG OR DRIZZLE ARE
POSSIBLE BY DAYBREAK MONDAY. LOW TEMPERATURES IN THE UPPER 50S AND
LOWER 60S ARE FORECAST SUNDAY NIGHT.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
MODELS ARE IN GOOD AGREEMENT WITH THE H5 PATTERN THROUGH THE MIDDLE
OF NEXT WEEK. SLIGHT DIFFERENCES COME INTO PLAY WITH TIMING AND
AMPLITUDE OF A SHORTWAVE TROUGH MOVING THROUGH NEW ENGLAND ON
WED...ALTHOUGH SHOWER/TSTM ACTIVITY CURRENTLY LOOKS TO REMAIN TO OUR
N. A VORTEX DEVELOPS OVER SE CANADA AT THE END OF THE WEEK WITH
ZONAL FLOW BECOMING SW ALOFT AS A PIECE OF ENERGY MOVING AROUND THE
BASE RESULTS IN AMPLIFICATION.
AT THE SFC...A FRONTAL BOUNDARY JUST TO THE SW OF THE AREA MON
MORNING...WILL REMAIN NEARLY STATIONARY AS SUBSIDENCE FROM HIGH PRES
TO THE NE NOSES IN. LOW LEVELS SATURATE EARLY IN THE MORNING AS A
RESULT WITH STRATUS EXPECTED AND WITH WEAK LIFT IN THE SATURATED
LAYER COULD CAUSE DRIZZLE. THERE IS ALSO A WEAK SHORTWAVE MOVING
THROUGH THE FLOW ALOFT WHICH COULD CAUSE A FEW AREAS OF RAIN. THE
LATTER WILL BE DETERMINED BY HOW MUCH DRY AIR IS IN PLACE ALOFT FROM
THE HIGH. HAVE ADDED SLIGHT CHANCE RAIN OR DRIZZLE FOR A FEW HOURS MON
MORNING AS A RESULT. WITH THE FRONT NEARBY THROUGH THE DAY...HAVE
MAINTAINED THE SLIGHT CHANCE POPS MAINLY FROM NYC AND AREAS N AND W FOR ANY
ACTIVITY THAT MAY DEVELOP IN THE AFTERNOON WITH WEAK AREAS OF VORTICITY
MOVING THROUGH THE MID-LEVELS. MON NIGHT MAY END UP BEING DRY FOR
THE MOST PART WITH MODEL TRENDS INDICATING THAT ANY ACTIVITY REMAINS
TO OUR SW...BUT MAINTAINED THE SLIGHT CHANCE TO LOW CHANCE POPS FOR THE TIME
BEING SINCE THERE IS UNCERTAINTY WITH HOW MUCH THE HIGH TO THE NE
BUILDS IN.
WARM FRONT LIFTS THROUGH TUE MORNING FOLLOWED BY A COLD FRONT IN THE
EVE WITH A BETTER CHANCE FOR WIDESPREAD SHOWERS/TSTMS. HIGH PRESSURE
THEN BUILDS IN FROM THE W AND REMAINS IN CONTROL THROUGH THE END OF
THE WEEK...WITH THE EXCEPTION OF MAYBE A SHOWER ASSOCIATED WITH A
WEAK COLD FRONT DROPPING THROUGH THE AREA ON FRI AFTERNOON/EVE.
TEMPERATURES WILL GENERALLY BE ABOVE NORMAL LEVELS THROUGH THE
PERIOD.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
A WARM FRONT LIFTS THROUGH THE REGION THIS AFTERNOON. A SURFACE
TROUGH THEN CROSSES THE AREA TONIGHT. A BACKDOOR COLD FRONT
APPROACHES FROM THE NORTH SUNDAY MORNING...THEN BEGINS TO SINK
SOUTH INTO THE TRI-STATE SUNDAY AFTERNOON.
VFR OUTSIDE OF CONVECTION THROUGH THIS EVENING...EXCEPT FOR MVFR
HAZE AT KHPN AND MVFR CEILINGS AT KGON.
FOR TERMINALS W OF HUDSON HAVE GONE WITH PREVAILING SHRA/TEMPO
TSRA LATE THIS AFTERNOON/EARLY THIS EVENING. FOR TERMINALS E OF
THE HUDSON HAVE GONE WITH VCTS WITH TEMPO SHRA THIS EVENING.
WITH ABUNDANT LOW-LEVEL MOISTURE ACROSS THE REGION AND LIGHT
WINDS...FOG/STRATUS WILL PROBABLY DEVELOP OVERNIGHT. FOR NOW HAVE
CONTINUED WITH LOW END MVFR FORECAST (3SM/1000FT)...HOWEVER
CANNOT RULE OUT IFR...OR EVEN VFR FOR THAT MATTER.
WINDS MAINLY LIGHT AND VARIABLE OUTSIDE OF SEABREEZES THIS
AFTERNOON...AND SOUND BREEZE KLGA AND SEABREEZE KJFK/KBDR/KGON
LATE SUNDAY MORNING/EARLY SUNDAY AFTERNOON.
.OUTLOOK FOR 18Z SUNDAY THROUGH WEDNESDAY...
.SUNDAY AFTERNOON/EVENING...MAINLY VFR. MVFR OR LOWER POSSIBLE IN
ANY ISOLD SHRA/TSTM.
.SUNDAY NIGHT-MONDAY EVENING...MVFR OR LOWER POSSIBLE IN
LOW CLOUDS/FOG. NE WINDS G15-20KT POSSIBLE DURING THE DAY ON
MONDAY.
.LATE MONDAY NIGHT-TUESDAY EVENING...MVFR OR LOWER POSSIBLE IN
FOG/STRATUS AND/OR SHRA/TSTM.
.LATE TUESDAY NIGHT-THURSDAY...VFR. NW WINDS G20+KT POSSIBLE.
&&
.MARINE...
S WINDS 10-20 KT ON THE OCEAN WATERS THIS AFTERNOON AND EVENING
DIMINISH TONIGHT. BRIEF GUSTY WINDS ARE ALSO POSSIBLE IN ANY
SHOWER AND THUNDERSTORMS THAT MAY MOVE ACROSS THE WATERS.
OTHERWISE...SUB-SCA CONDITIONS ARE FORECAST FOR THE REMAINDER OF
THE FORECAST PERIOD WITH A RELATIVELY LIGHT FLOW PERSISTING ACROSS
THE AREA. GUSTS MAY REACH AROUND 20 KT LATE TUE NIGHT THROUGH
WED.
&&
.HYDROLOGY...
BASIN AVERAGE RAINFALL OF 1/4 INCH IS POSSIBLE THROUGH SUNDAY
MORNING WITH LOCALIZED HIGHER AMOUNTS IN A BAND OF SHOWERS AND
THUNDERSTORMS. MINOR URBAN FLOODING IS POSSIBLE IN ANY OF THE
HEAVIER SHOWERS/STORMS.
AROUND 1/4 OF AN INCH OF RAINFALL IS POSSIBLE WITH THE FRONTAL
SYSTEM ON TUE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DS/24
NEAR TERM...DS
SHORT TERM...DS
LONG TERM...24
AVIATION...MALOIT
MARINE...DS/24
HYDROLOGY...DS/24
AREA FORECAST DISCUSSION
NWS NEW YORK NY
139 PM EDT SAT MAY 16 2015
.SYNOPSIS...
A WARM FRONT WILL BE SLOW TO PUSH NORTH OF THE AREA THIS AFTERNOON...
WHILE A TROUGH OF LOW PRESSURE APPROACHES FROM THE WEST THIS
EVENING AND STALLS OUT ACROSS THE AREA ON SUNDAY. A BACKDOOR COLD
FRONT MOVES THROUGH LATE SUNDAY NIGHT AS HIGH PRESSURE BUILDS
SOUTH ALONG THE NEW ENGLAND COAST. THE FRONT WILL THEN RETURN
NORTH AS A WARM FRONT TUESDAY MORNING...FOLLOWED BY A COLD FRONT
LATE TUESDAY. HIGH PRESSURE WILL THEN BUILD IN FOR THE END OF THE
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WARM FRONT LOCATED NEAR THE NYC METRO AS OF 17Z WILL CONTINUE TO
SLOWLY LIFT NE OF THE AREA THROUGH THIS AFTERNOON. ENOUGH BREAKS
IN THE CLOUDS SHOWING UP ON VISIBLE SATELLITE IMAGERY FOR HIGHER
CONFIDENCE IN ACHIEVING HIGH TEMPERATURE FORECAST OF HIGHS IN THE
LOWER 80S INLAND AND INVOF NYC METRO...AND MAINLY IN THE 70S
ELSEWHERE.
INSTABILITY WILL BEGIN TO INCREASE THIS AFTERNOON WEST OF THE
HUDSON RIVER AHEAD OF MID LEVEL IMPULSE AND WEAK SHORTWAVE. A LEE
TROUGH ALSO DEVELOPS ACROSS E PA AND APPROACHES LATE THIS
AFTERNOON. LATEST 15Z HRRR GUIDANCE AS WELL AS ITS PREVIOUS
SEVERAL RUNS HAVE A BAND OF CONVECTION MOVING INTO THE LOWER
HUDSON VALLEY AROUND 21-22Z. THIS HAS SUPPORT FROM THE 12Z NAM AND
15Z RAP AS WELL AS THE 00Z SPC WRF. SURFACE BASED INSTABILITY
DIFFERS SOMEWHAT AMONG THE MODEL GUIDANCE...BUT HAVE ENOUGH
CONFIDENCE THAT 800 TO 1200 J/KG OF SURFACE BASED CAPE WILL BE
AVAILABLE ACROSS THE FAR NW INTERIOR FOR CONVECTION TO TAP INTO
LATE THIS AFTERNOON AS IT MOVES INTO THE AREA. MODERATELY STRONG
WESTERLY LOW-MID LEVEL FLOW SUPPORTS UNIDIRECTIONAL SHEAR AROUND
30 KT.
THE STREAK OF 23 CONSECUTIVE DAYS...APRIL 23 TO MAY 15...OF NO
MEASURABLE PRECIPITATION AT CENTRAL PARK HAS ENDED TODAY WITH 0.09
INCHES OF RAIN OCCURRING THIS MORNING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
A BAND OF CONVECTION WILL BE MOVING INTO LOCATIONS WEST OF THE
HUDSON RIVER THIS EVENING...REACHING THE NYC METRO AROUND 00Z. A
MARGINAL RISK OF SEVERE WEATHER PER SPC CONTINUES WEST OF THE
HUDSON RIVER WHERE GREATEST SURFACE BASED INSTABILITY WILL RESIDE.
THE THREAT IS FOR A STORM OR TWO TO CONTAIN DAMAGING WIND GUSTS. WITH
MARITIME INFLUENCE FURTHER EAST...INSTABILITY WILL BE ELEVATED
WITH LOWER CHANCE FOR ANY SEVERE CONVECTION. CONVECTION LIKELY
BECOMES ELEVATED AND WEAKER AS IT MOVES EAST OF THE HUDSON.
HOWEVER...MULTIPLE SHORT WAVES ALOFT ROUNDING THE TOP OF THE RIDGE
MAY HELP TO SUSTAIN THE COMPLEX AS IT WORKS TOWARD THE COAST. HIGH
PW VALUES WILL ALSO MEAN THERE IS THE POTENTIAL FOR BRIEF HEAVY
DOWNPOURS. MINOR URBAN FLOODING IS A POSSIBILITY.
CONVECTION IS FORECAST TO DISSIPATE BY DAYBREAK SUN WITH A
QUIETER DAY EXPECTED WITH THE UPPER RIDGE BUILDING DIRECTLY
OVERHEAD. SHOULD SEE SOME PARTIAL CLEARING WITH HIGHS ABOVE NORMAL
BY ABOUT TEN DEGREES.
UPPER RIDGE AXIS BUILDS INTO THE CANADIAN MARITIMES SUN
NIGHT...STRENGTHENING THE LOW-LEVEL RIDGE ACROSS THE NE AND
ALLOWING FOR A BACKDOOR COLD FRONTAL PASSAGE. THIS SHOULD RESULT
IN MUCH COOLER CONDITIONS WORKING IN ON MON.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE WESTWARD EXTENT OF THE BACKDOOR COLD FRONT WILL BE A KEY
PLAYER IN DETERMINING IF THE AREA STAYS OUT OF CONVECTION ON MON
AND HOW COOL TEMPS GET. 00Z CYCLE SHOWS THE FRONT GETTING TO THE
LEE OF THE POCONOS AND CATSKILLS. THIS MAY RESULT IS SOME SHOWER
ACTIVITY OVER THE WESTERN PORTIONS OF THE AREA.
THE FRONT APPROACHES AS WARM FRONT TUE MORNING. THE FLOW ALOFT
TURNS MORE CYCLONIC...AND INCREASING MOISTURE AND LIFT COULD
PRODUCE SOME SHOWERS...PRIMARILY OVER THE WESTERN HALF OF THE CWA.
A TRAILING COLD FRONT APPROACHES TUE AFT AND IS PROGGED TO BE
THROUGH BY EARLY EVENING. THERE IS A GOOD CHANCE OF CONVECTION
ALONG AND AHEAD OF THE FRONT TUE.
HIGH PRESSURE BUILDS IN FOR WEDNESDAY THROUGH FRIDAY. A MODERATE
DOWNSLOPE FLOW SHOULD BE ABLE TO OFFSET SOME OF THE COLD AIR
ADVECTION...KEEPING HIGHS NEAR NORMAL ON WEDNESDAY. TEMPS ALOFT
THEN WARM UP ON THURSDAY AND FRIDAY...WITH HIGHS A LITTLE WARMER
THAN THOSE ON WEDNESDAY.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
A WARM FRONT LIFTS THROUGH THE REGION THIS AFTERNOON. A SURFACE
TROUGH THEN CROSSES THE AREA TONIGHT. A BACKDOOR COLD FRONT
APPROACHES FROM THE NORTH SUNDAY MORNING...THEN BEGINS TO SINK
SOUTH INTO THE TRI-STATE SUNDAY AFTERNOON.
VFR OUTSIDE OF CONVECTION THROUGH THIS EVENING...EXCEPT FOR IFR
NEXT COUPLE OF HOURS AT KGON.
FOR TERMINALS W OF HUDSON HAVE GONE WITH PREVAILING SHRA/TEMPO
TSRA LATE THIS AFTERNOON/EARLY THIS EVENING. FOR TERMINALS E OF
THE HUDSON HAVE GONE WITH VCTS WITH TEMPO SHRA THIS EVENING.
WITH ABUNDANT LOW-LEVEL MOISTURE ACROSS THE REGION AND LIGHT
WINDS...FOG/STRATUS WILL PROBABLY DEVELOP OVERNIGHT. FOR NOW HAVE
CONTINUED WITH LOW END MVFR FORECAST (3SM/1000FT)...HOWEVER
CANNOT RULE OUT IFR...OR EVEN VFR FOR THAT MATTER.
WINDS MAINLY LIGHT AND VARIABLE OUTSIDE OF SEABREEZES THIS
AFTERNOON...AND SOUND BREEZE KLGA AND SEABREEZE KJFK/KBDR/KGON
LATE SUNDAY MORNING/EARLY SUNDAY AFTERNOON.
.OUTLOOK FOR 18Z SUNDAY THROUGH WEDNESDAY...
.SUNDAY AFTERNOON/EVENING...MAINLY VFR. MVFR OR LOWER POSSIBLE IN
ANY ISOLD SHRA/TSTM.
.SUNDAY NIGHT-MONDAY EVENING...MVFR OR LOWER POSSIBLE IN
LOW CLOUDS/FOG. NE WINDS G15-20KT POSSIBLE DURING THE DAY ON
MONDAY.
.LATE MONDAY NIGHT-TUESDAY EVENING...MVFR OR LOWER POSSIBLE IN
FOG/STRATUS AND/OR SHRA/TSTM.
.LATE TUESDAY NIGHT-THURSDAY...VFR. NW WINDS G20+KT POSSIBLE.
&&
.MARINE...
S WINDS 5-10 KT BECOME 10-20 KT ON THE OCEAN WATERS THIS
AFTERNOON...THEN WILL DIMINISH TONIGHT. WITH A LIGHT PRES GRADIENT
OVER THE AREA THROUGH THE START OF THE NEW WEEK...SUB-SCA
CONDITIONS ON TAP WITH SEAS 2-4 FT ON THE OCEAN WATERS AND 1 FT
OR LESS ON THE SOUND/HARBOR/BAYS.
&&
.HYDROLOGY...
BASIN AVG RAINFALL OF 1/4 TO 1/2 INCH IS POSSIBLE THROUGH TONIGHT
WITH LOCALIZED HIGHER AMOUNTS AS A COMPLEX OF SHOWERS AND
THUNDERSTORMS MOVES IN FROM PA TONIGHT.
A QUARTER TO HALF INCH OF RAINFALL IS POSSIBLE LATE MONDAY NIGHT
THROUGH TUESDAY WITH A COLD FRONTAL PASSAGE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...DW
NEAR TERM...DS/DW
SHORT TERM...DS/DW
LONG TERM...DW/JC
AVIATION...MALOIT
MARINE...MPS
HYDROLOGY...DW
AREA FORECAST DISCUSSION
NWS TAUNTON MA
716 AM EDT SAT MAY 16 2015
.SYNOPSIS...
SCATTERED SHOWERS THIS MORNING AS A WARM FRONT MOVES ACROSS THE
REGION. WARM AND MORE HUMID WEATHER FOLLOWS SUNDAY. THEN A
BACKDOOR COLD FRONT USHERS IN MUCH COOLER AIR INTO THE REGION
SUNDAY NIGHT THROUGH EARLY NEXT WEEK. ANOTHER COLD FRONT WILL
BRING SCATTERED SHOWERS TO THE REGION MON NIGHT INTO TUE FOLLOWED
BY DRY WEATHER MID TO LATE NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
715 AM UPDATE...
BATCH OF SHOWERS MOVING EWD THROUGH CT THIS MORNING WILL BE
FOCUSED MAINLY ALONG THE CT S COAST TO COASTAL RI...WITH ISOLD
SHOWERS POSSIBLE REMAINDER OF SNE THIS MORNING. SOME ELEVATED
INSTABILITY EXISTS AND NOTED SOME LIGHTNING EARLIER ACROSS SE NY
SO CANT RULE OUT AN ISOLD TSTM ACROSS S COASTAL RI. HRRR SUGGESTS
SHOWERS EXITING THE REGION BY MIDDAY. UPDATED POPS TO REFLECT
CURRENT RADAR TRENDS.
PREVIOUS DISCUSSION...
AFTER THIS MORNING...EXPECT LITTLE IN THE WAY OF PRECIP FOR THE
REMAINDER OF THE DAY. THE EXCEPTION TO THIS COULD BE LATE IN THE
DAY CONVECTION FROM WESTERN NEW YORK STATE/PENNSYLVANIA COULD MOVE
EASTWARD INTO THE SOUTHWESTERN PORTIONS OF SOUTHERN NEW ENGLAND.
WITH MOSTLY CLOUDY SKIES MUCH OF THE DAY AND DIMINISHING DAYTIME
INSTABILITY...EXPECT A FEW SHOWERS TO BE THE EXTENT OF THE PRECIP
REACHING THIS AREA.
TEMPERATURE FORECAST IS A BIT COMPLICATED. WHILE NOT EXPECTING
WIDESPREAD PRECIP TODAY...DO EXPECT SKY TO REMAIN MOSTLY CLOUDY TO
OVERCAST. THIS COULD LIMIT TEMPERATURES SOMEWHAT...THOUGH ANY PEEKS
OF SUN WILL ALLOW TEMPS TO JUMP UP. FOR NOW...WENT AGAIN WITH THE
HIRES GUIDANCE WHICH GAVE HIGH TEMPS AROUND 70 FOR MUCH OF THE
REGION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
TONIGHT...UPPER RIDGE CONTINUES TO BUILD INTO THE NORTHEAST U.S.
WHILE THE WARM FRONT CONTINUES TO MOVE NORTH OF SOUTHERN NEW
ENGLAND. ASIDE FROM THE FEW SHOWERS MENTIONED ABOVE...EXPECT MUCH
OF THE NIGHT TO BE DRY. OVERCAST SKIES CONTINUE...INSULATING US
FROM ABOVE. OVERNIGHT LOWS ARE EXPECTED TO BE IN THE UPPER 50S TO
AROUND 60.
SUNDAY...THE BACK DOOR COLD FRONT HAS SLOWED SUBSTANTIALLY SINCE
LAST NIGHTS MODEL RUNS. THIS WILL LEAD TO A MUCH WARMER DAY THAN
PREVIOUSLY FORECAST. UPPER RIDGE HOLDS STRONG ACROSS THE NORTHEAST
AND SEABREEZES ARE LIKELY TO DEVELOP WITH LIGHT FLOW ALOFT. THIS
WILL KEEP TEMPERATURES ALONG THE IMMEDIATE COAST IN THE MID TO UPPER
60S. HOWEVER...FARTHER INLAND...HIGHS SHOULD CLIMB INTO THE LOW 80S
FOR MOST LOCATIONS. EXPECT MOSTLY SUNNY SKIES AS WELL WITH DIURNAL
CU FORMING DURING THE AFTERNOON HOURS. SHOULD BE THE PICK OF THE
WEEKEND.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
HIGHLIGHTS...
* MAINLY DRY AND COOLER SUN NIGHT AND MONDAY
* A PERIOD OF SHOWERS LIKELY MON NIGHT AND TUE FOLLOWED BY DRY AND
SEASONABLE WEATHER MID TO LATE NEXT WEEK
OVERVIEW...
MODELS ARE IN GOOD AGREEMENT ON THE LARGE SCALE FLOW DURING THE
EXTENDED PERIOD. MID LEVEL SHORTWAVE MOVING S FROM NOVA SCOTIA WILL
BRING A BACKDOOR FRONT ACROSS SNE SUN NIGHT WHICH WILL USHER IN A
MUCH COOLER MARITIME AIRMASS LATE SUN NIGHT INTO MON. THEN NEXT MID
LEVEL TROF MOVES EAST FROM THE UPPER MIDWEST WHICH WILL LIKELY BRING
A PERIOD OF SHOWERS MON NIGHT AND ESPECIALLY TUE. THIS TROF WILL
SETTLE ACROSS SE CANADA MID TO LATE WEEK BRINGING MAINLY DRY AND
SEASONABLE WEATHER.
SUN NIGHT AND MON...
BACKDOOR FRONT MOVES ACROSS SNE SUN NIGHT AS STRONG RIDGE NOSES DOWN
FROM THE MARITIMES TO THE GULF OF MAINE. LOW LEVEL NE FLOW WILL LEAD
TO INCREASING LOW LEVEL MOISTURE AND AN EXPANSION OF STRATUS AND
PATCHY FOG LATE SUN NIGHT INTO EARLY MON ALONG WITH THE POSSIBILITY
OF SOME PATCHY DRIZZLE. CLOUDS SHOULD LIFT AND GIVE WAY TO PTSUNNY
SKIES BY MON AFTERNOON...BUT CLOUDS COULD LINGER ALONG THE COAST.
WITH DEVELOPING SUNSHINE HIGHS ON MON SHOULD RECOVER INTO THE
MID/UPPER 60S AND SOME LOWER 70S CT VALLEY...BUT CLOSER TO 60 ALONG
E COASTAL MA.
MON NIGHT INTO TUE...
DEEPENING MOISTURE PLUME AHEAD OF APPROACHING COLD FRONT MOVES INTO
SNE LATE MON NIGHT AND TUE. MODEST LOW LEVEL JET ACTING ON 1.5"+
PWATS ALONG WITH MARGINAL ELEVATED INSTABILITY WILL RESULT IN A
PERIOD OF SHOWERS AND PERHAPS AN ISOLD TSTM LATE MON NIGHT INTO TUE.
TIMING NOT CERTAIN AT THIS TIME RANGE BUT IT APPEARS BEST CHANCE OF
SHOWERS WILL BE DURING TUE...ESPECIALLY AFTERNOON ACROSS E NEW ENG.
HIGHS TUE IN THE 60S. A FEW SHOWERS COULD LINGER INTO TUE EVENING
ALONG THE COAST...OTHERWISE DRYING MOVES IN TUE NIGHT BEHIND THE
FRONT.
WED THROUGH FRI...
LONG WAVE TROF SETS UP ACROSS SE CANADA WITH HIGH PRES IN CONTROL
LEADING TO MAINLY DRY AND SEASONABLE CONDITIONS.
&&
.AVIATION /11Z SATURDAY THROUGH WEDNESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH SUNDAY/...
TODAY...HIGH CONFIDENCE. MAINLY VFR. A FEW SHOWERS THIS MORNING
WITH BRIEF MVFR VSBY POSSIBLE ESPECIALLY CT AND S RI.
TONIGHT...HIGH CONFIDENCE. MAINLY VFR. LOW PROBABILITY OF MVFR
CONDITIONS IN LOW CLOUDS AND PATCHY FOG.
SUNDAY...HIGH CONFIDENCE. VFR. SEABREEZES DEVELOP ALONG THE EAST
AND SOUTH COASTS ABOUT 14-15Z.
KBOS TERMINAL...HIGH CONFIDENCE IN TAF.
KBDL TERMINAL...HIGH CONFIDENCE IN TAF.
OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY...
SUN NIGHT AND MON...MODERATE CONFIDENCE. WINDS BECOMING NE FROM E TO
W SUN NIGHT BEHIND A BACKDOOR FRONT WITH IFR STRATUS AND PATCHY FOG
DEVELOPING LATE SUN NIGHT INTO MON MORNING...THEN IMPROVING TO VFR
MON AFTERNOON BUT MVFR CIGS MAY LINGER ALONG THE COAST.
MON NIGHT AND TUE...MODERATE CONFIDENCE. AREAS OF MVFR/IFR
REDEVELOPING WITH SCT TO NUMEROUS SHOWERS AND POSSIBLY A
TSTM...ESPECIALLY TUE.
WED...MODERATE CONFIDENCE. VFR. DRY WEATHER LIKELY.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH SUNDAY/...HIGH CONFIDENCE.
QUIET BOATING WEATHER EXPECTED WITH HIGH PRESSURE OVER THE
WATERS. SOUTHERLY WINDS 10 TO 15 KTS THROUGH THE PERIOD WITH GUSTS
TO 20 KTS TODAY...SHIFTING TO LIGHT AND VARIABLE SUNDAY.
OUTLOOK...SUNDAY NIGHT THROUGH WEDNESDAY...
SUN NIGHT AND MON...HIGH CONFIDENCE. A PERIOD OF NE GUSTS TO 20 KT
LIKELY LATE SUN NIGHT INTO EARLY MON...WITH E WINDS MON AFTERNOON
TURNING SOUTHERLY MON NIGHT. VSBYS MAY BE REDUCED IN PATCHY FOG.
TUE...HIGH CONFIDENCE. PREFRONTAL S/SW WINDS INCREASING TO 20 KT
INTO TUE EVENING WITH LOW PROB FOR A FEW G25 KT...THEN SHIFTING TO
NW LATE MON NIGHT BEHIND FROPA. SHOWERS AND PATCHY FOG WILL
REDUCE VSBYS.
WED...HIGH CONFIDENCE. W/NW WINDS WITH GUSTS TO 20-25 KT. MARGINAL
SCA CONDITIONS POSSIBLE.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KJC/RLG
NEAR TERM...KJC/RLG
SHORT TERM...RLG
LONG TERM...KJC
AVIATION...KJC/RLG
MARINE...KJC/RLG
AREA FORECAST DISCUSSION
NWS ALBANY NY
159 AM EDT SAT MAY 16 2015
.SYNOPSIS...
A WARM FRONT AND WEAK LOW PRESSURE SYSTEM WILL MOVE INTO THE REGION
OVERNIGHT AND DRIFT ACROSS THE AREA SATURDAY WITH SHOWERS AND
ISOLATED THUNDERSTORMS. HIGH PRESSURE WILL CREST OVER THE REGION
SUNDAY... AND SLIDE OFFSHORE SUNDAY NIGHT WITH FAIR AND MAINLY DRY
AND WARM WEATHER SUNDAY INTO MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CLOUD COVER CONTINUES TO LOWER WITH SHOWERS DEVELOPING AND MOVING
INTO THE FORECAST AREA AHEAD OF THE APPROACHING WARM FRONT/LOW
PRESSURE SYSTEM AND UPPER LEVEL SHORT WAVE TROUGH. SHOWERS HAVE
BEEN VERY LIGHT THUS FAR AS THE ATMOSPHERE IS RATHER DAY AS NOTED
BY THE VERY DRY LAYER FROM 1000-700 MB ON THE 00Z/ALY SOUNDING.
HRRR SHOWS SHOWERS MOVING ACROSS THE AREA THROUGH THE EARLY
MORNING HOURS. USED REGIONAL RADARS AND HRRR TO ADJUST POPS. THERE
HAS BEEN A FEW LIGHTNING STRIKES ACROSS CENTRAL NEW YORK WHICH
LINES UP FAIRLY WELL WITH THE MODELED SHOWALTER INDICES. THE
-2 TO ZERO INDICES MOVES ACROSS THE SOUTHERN PORTION OF THE
FORECAST AREA...USED THIS AS A GUIDE WHERE TO MENTION SLIGHT
CHANCE OF THUNDER FOR THE OVERNIGHT/EARLY MORNING HOURS.
OVERALL DID ADJUST TEMPERATURES UP A BIT...HAVE LOWS MAINLY IN THE
50S WITH SOME 40S ACROSS THE HIGHER TERRAIN OF THE SOUTHERN
ADIRONDACKS AND SOUTHERN GREEN MOUNTAINS INTO THE NORTHERN
BERKSHIRES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
THE WARM FRONT WILL CROSS THE REGION SATURDAY MORNING AND THAT
SHOULD BRING TO AN END ANY STEADY RAINFALL THAT MAY OCCUR AHEAD OF
IT. A WEAK COLD FRONT AND SOME DRIER AIR WILL TRY TO PUSH
SOUTHWARD INTO THE REGION SATURDAY AFTN AND NIGHT. IT WILL NOT BE
SOUTH OF THE REGION UNTIL EARLY SUNDAY MORNING. AS A RESULT...
THERE WILL STILL BE A CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS
SATURDAY AFTN AND NIGHT...ESPECIALLY AREAS SOUTH OF ALBANY. HAVE
GENERALLY FORECAST 20 TO 30 PERCENT POPS FROM THE CAPITAL DISTRICT
NORTH DURING SATURDAY AFTERNOON...AND 30 TO 40 PERCENT POPS TO
THE SOUTH. THESE POPS CONTINUE TO DECREASE SATURDAY NIGHT WITH
MOST OF THE REGION DRY BY SUNRISE SUNDAY.
THE DRIER AIR BEHIND THIS WEAK COLD FRONT WILL RESULT IN FAIR AND
WARM WEATHER SUNDAY AND SUNDAY NIGHT.
HIGHS SATURDAY WILL BE IN THE UPPER 60S AND 70S. LOWS SATURDAY
NIGHT GENERALLY 50 TO 60. HIGHS SUNDAY 75 TO 85. LOWS SUNDAY NIGHT IN
THE UPPER 40S AND 50S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE LONG TERM PERIOD WILL BEGIN SOMEWHAT UNSETTLED...BEFORE FAIR
WEATHER AND COOLER TEMPERATURES DOMINATE FOR THE BULK OF THE
REMAINDER OF THE LONG TERM.
FOR MON...A SHARP UPPER LEVEL RIDGE WILL CREST OVER THE REGION
BEFORE MOVING OFF THE NEW ENGLAND COAST LATE IN THE DAY. AT THE
SFC...A BACKDOOR COLD FRONTAL BOUNDARY SHOULD START OUT ACROSS
CENTRAL NYS...POSSIBLY EXTREME WESTERN AREAS OF THE REGION IN THE
MORNING. THIS BOUNDARY SHOULD WEAKEN...BEFORE DRIFTING BACK EAST
LATER IN THE DAY. ALSO...A MUCH STRONGER COLD FRONT WILL BE
APPROACHING FROM THE GREAT LAKES REGION. IT APPEARS THAT SHOWERS
SHOULD SLOWLY EXPAND EASTWARD ACROSS THE REGION DURING THE DAY.
HOWEVER...GIVEN THE SHARPNESS OF THE UPPER LEVEL RIDGE...IT IS QUITE
POSSIBLE THAT AREAS EAST OF THE HUDSON RIVER REMAIN DRY THROUGH
SUNSET. SO...WILL ONLY GRADUALLY INCREASE POPS INTO THE CHC RANGE
FOR WESTERN AREAS...AND MAINLY SLIGHT CHC FOR EASTERN AREAS BY LATE
IN THE DAY...WITH MAINLY DRY CONDITIONS FOR ALL AREAS IN THE
MORNING. TEMPERATURES WILL BE WARMEST ACROSS THE SOUTHERN
ADIRONDACKS AND WESTERN MOHAWK RIVER VALLEY...WHERE TEMPS NEAR 80
ARE EXPECTED. ELSEWHERE...A MARINE MODIFIED AIR MASS SHOULD RESULT
IN SLIGHTLY COOLER TEMPS FURTHER SOUTH AND EAST...WITH GENERALLY 70S
FOR VALLEYS...AND UPPER 60S/LOWER 70S ACROSS HIGHER ELEVATIONS.
MON NT-TUE...THE COLD FRONT ACROSS THE GREAT LAKES REGION SHOULD
SLOWLY SWING EAST ACROSS THE REGION. THIS SHOULD RESULT IN SOME
ROUNDS OF SHOWERS AND POSSIBLE THUNDERSTORMS. THE BEST CHANCE FOR
SIGNIFICANT RAINFALL WILL BE ACROSS THE SOUTHERN ADIRONDACKS AND
WESTERN MOHAWK VALLEY...WHICH WILL BE CLOSER TO THE PASSING UPPER
LEVEL DYNAMICS. SHOWERS MAY TEND TO BECOME MORE SCATTERED FOR AREAS
SOUTH AND EAST OF ALBANY. DEPENDING ON THE SPEED OF THE
FRONT...SHOWERS MAY TEND TO TAPER OFF FROM NW TO SE TUE AFTERNOON.
ALTHOUGH MID/UPPER LEVEL WINDS WILL STRENGTHEN...AT THIS TIME...MID
LEVEL LAPSE RATES DO NOT APPEAR VERY STRONG...SO AT LEAST AT THIS
TIME RANGE...IT APPEARS THAT THE OVERALL THREAT FOR WIDESPREAD
STRONG/SEVERE THUNDERSTORMS SHOULD BE LOW. MON NT/TUE AM MIN TEMPS
SHOULD BE MILD...MAINLY IN THE 50S TO LOWER 60S. TUE MAX TEMPS ARE
TRICKY...DEPENDING ON HOW MUCH SUN CAN BREAK OUT. ASSUMING CLOUDS
REMAIN FAIRLY WIDESPREAD...CURRENT FORECAST MAX TEMPS ARE IN THE 70-
75 RANGE IN VALLEYS AND 60S ACROSS HIGHER ELEVATIONS. HOWEVER...IF
THE FRONT SLOWS DOWN AND SOME BREAKS CAN DEVELOP...MUCH WARMER MAXES
COULD OCCUR.
TUE NT-FRI...LARGE HIGH PRESSURE SHOULD SLOWLY BUILD ACROSS THE
REGION FROM THE GREAT LAKES. MOST LONG TERM GUIDANCE SUGGESTS
ANOMALOUSLY COOL MID/UPPER LEVEL HEIGHTS AND CORRESPONDING H925-850
TEMPS. THERE COULD BE SPOTTY SHOWERS/SPRINKLES IN ASSOCIATION WITH
THE UPPER LEVEL COLD POOL AND EVEN SOME WEAK LAKE EFFECT PROCESSES
FOR TUE NT-WED ACROSS THE SOUTHWEST ADIRONDACKS. OTHERWISE...TEMPS
WILL BE QUITE COOL WED...WITH MAXES ONLY REACHING 60-65 IN
VALLEYS...AND 50S FOR MOST HIGHER ELEVATIONS...ALTHOUGH SOME OF THE
HIGHEST PEAKS OF THE SOUTHERN ADIRONDACKS AND SOUTHERN VT MAY ONLY
REMAIN IN THE 40S. OVERNIGHT MIN TEMPS FOR TUE NT/WED AM WILL MAINLY
BE IN THE 40S TO LOWER 50S. FOR WED NT/THU AM...MIN TEMPS SHOULD BE
EVEN COOLER...WITH 30S ACROSS THE WESTERN ADIRONDACKS...AND 40S
ELSEWHERE. THERE COULD BE SOME FROST ACROSS PORTIONS OF THE SOUTHERN
ADIRONDACKS...WHERE THE GROWING SEASON BEGINS MAY 21. THU AND FRI
MAX TEMPS SHOULD WARM SLIGHTLY...WITH LOWER 70S IN VALLEYS AND 60S
ACROSS HIGHER ELEVATIONS. MIN TEMPS FOR THU NT/FRI AM SHOULD FALL
INTO THE 40S FOR MOST AREAS.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
A WARM FRONT WILL MOVE ACROSS ERN NY AND WRN NEW ENGLAND LATE THIS
MORNING INTO THE EARLY AFTERNOON. THE REGION WILL BE IN A WARM
SECTOR BRIEFLY LATE THIS AFTERNOON INTO THE EARLY EVENING. A COLD
FRONT WILL MOVE THROUGH TONIGHT...BEFORE HIGH PRESSURE RIDGES IN
FOR SUNDAY.
VFR CONDITIONS THIS MORNING WILL LOWER TO HIGH MVFR LEVELS IN
TERMS OF VSBYS/CIGS WITH THE SHOWERS AHEAD OF THE WARM FRONT.
THERE MAYBE A BRIEF RUMBLE OF THUNDER...BUT SINCE IT IS ISOLATED
NO THUNDERSTORMS WERE ADDED TO THE TAF SITES AT THIS TIME. THE
BEST CHC OF MVFR CIGS/VSBYS WILL BE BTWN 08Z-14Z. THE CONDITIONS
WILL INCREASE BACK TO VFR LEVELS AFTER THE SHOWERS. SCT-BKN
CUMULUS AND MID LEVEL CLOUDINESS WILL LINGER IN THE LATE MORNING
INTO THE AFTERNOON.
THE COLD FRONT AND A PREFRONTAL DISTURBANCE WILL APPROACH LATE IN
THE PM INTO THE EARLY EVENING. A VCSH GROUP WAS PLACED IN
KGFL/KALB/KPOU/KPSF IN THE 21Z-23Z TIME FRAME. LATER TAF ISSUANCES
MAY HAVE TO ADD THUNDERSTORMS IF CONFIDENCE INCREASES.
THE WINDS WILL BE LIGHT FROM THE S TO SE AT 5 KTS OR LESS THAN
MORNING...THEN INCREASE FROM THE S AT 5-10 KTS IN THE LATE MORNING
INTO THE AFTERNOON.
OUTLOOK...
SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...TSRA.
SUNDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
TUESDAY: MODERATE OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
TUESDAY NIGHT: ISOLATED SHRA.
WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
A WARM FRONT AND WEAK LOW PRESSURE SYSTEM WILL MOVE INTO THE REGION
TONIGHT AND DRIFT ACROSS THE AREA SATURDAY WITH SHOWERS AND ISOLATED
THUNDERSTORMS. HIGH PRESSURE WILL CREST OVER THE REGION SUNDAY...
AND SLIDE OFFSHORE SUNDAY NIGHT WITH FAIR AND MAINLY DRY AND WARM
WEATHER SUNDAY INTO MONDAY.
WINDS WILL BE LIGHT AND VARIABLE TONIGHT AND RH VALUES WILL BE 90
TO 100 PERCENT. WINDS WILL BECOME SOUTHWEST SATURDAY AT 10 TO 15
MPH WITH RH 50 TO 60 PERCENT. RAINFALL TONIGHT AND SATURDAY MAY
PRODUCE UP TO A QUARTER TO A THIRD OF INCH. DRY WEATHER IS
EXPECTED SUNDAY AND MONDAY.
&&
.HYDROLOGY...
THE NEXT CHANCE OF SHOWERS WILL BE TONIGHT INTO SATURDAY...WITH
RAINFALL AMOUNTS EXPECTED TO BE AROUND A QUARTER TO A THIRD OF AN
INCH. THIS WILL HAVE LITTLE IMPACT ON AREA RIVERS AND STREAMS.
ONLY ISOLATED TO SCATTERED SHOWERS ARE EXPECTED SATURDAY AFTERNOON
AND NIGHT...WITH MAINLY DRY WEATHER EXPECTED FOR SUNDAY.
ANOTHER ROUND OF RAIN IS LIKELY LATE MONDAY INTO TUESDAY WITH THE
POTENTIAL FOR ANOTHER QUARTER TO THIRD OF AN INCH.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...IAA/GJM
NEAR TERM...IAA/KL/GJM/LFM
SHORT TERM...GJM
LONG TERM...KL
AVIATION...WASULA
FIRE WEATHER...GJM
HYDROLOGY...GJM
AREA FORECAST DISCUSSION
NWS ALBANY NY
139 AM EDT SAT MAY 16 2015
.SYNOPSIS...
A WARM FRONT AND WEAK LOW PRESSURE SYSTEM WILL MOVE INTO THE REGION
OVERNIGHT AND DRIFT ACROSS THE AREA SATURDAY WITH SHOWERS AND
ISOLATED THUNDERSTORMS. HIGH PRESSURE WILL CREST OVER THE REGION
SUNDAY... AND SLIDE OFFSHORE SUNDAY NIGHT WITH FAIR AND MAINLY DRY
AND WARM WEATHER SUNDAY INTO MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
CLOUD COVER CONTINUES TO LOWER WITH SHOWERS DEVELOPING AND MOVING
INTO THE FORECAST AREA AHEAD OF THE APPROACHING WARM FRONT/LOW
PRESSURE SYSTEM AND UPPER LEVEL SHORT WAVE TROUGH. SHOWERS HAVE
BEEN VERY LIGHT THUS FAR AS THE ATMOSPHERE IS RATHER DAY AS NOTED
BY THE VERY DRY LAYER FROM 1000-700 MB ON THE 00Z/ALY SOUNDING.
HRRR SHOWS SHOWERS MOVING ACROSS THE AREA THROUGH THE EARLY
MORNING HOURS. USED REGIONAL RADARS AND HRRR TO ADJUST POPS. THERE
HAS BEEN A FEW LIGHTNING STRIKES ACROSS CENTRAL NEW YORK WHICH
LINES UP FAIRLY WELL WITH THE MODELED SHOWALTER INDICES. THE
-2 TO ZERO INDICES MOVES ACROSS THE SOUTHERN PORTION OF THE
FORECAST AREA...USED THIS AS A GUIDE WHERE TO MENTION SLIGHT
CHANCE OF THUNDER FOR THE OVERNIGHT/EARLY MORNING HOURS.
OVERALL DID ADJUST TEMPERATURES UP A BIT...HAVE LOWS MAINLY IN THE
50S WITH SOME 40S ACROSS THE HIGHER TERRAIN OF THE SOUTHERN
ADIRONDACKS AND SOUTHERN GREEN MOUNTAINS INTO THE NORTHERN
BERKSHIRES.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
THE WARM FRONT WILL CROSS THE REGION SATURDAY MORNING AND THAT
SHOULD BRING TO AN END ANY STEADY RAINFALL THAT MAY OCCUR AHEAD OF
IT. A WEAK COLD FRONT AND SOME DRIER AIR WILL TRY TO PUSH
SOUTHWARD INTO THE REGION SATURDAY AFTN AND NIGHT. IT WILL NOT BE
SOUTH OF THE REGION UNTIL EARLY SUNDAY MORNING. AS A RESULT...
THERE WILL STILL BE A CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS
SATURDAY AFTN AND NIGHT...ESPECIALLY AREAS SOUTH OF ALBANY. HAVE
GENERALLY FORECAST 20 TO 30 PERCENT POPS FROM THE CAPITAL DISTRICT
NORTH DURING SATURDAY AFTERNOON...AND 30 TO 40 PERCENT POPS TO
THE SOUTH. THESE POPS CONTINUE TO DECREASE SATURDAY NIGHT WITH
MOST OF THE REGION DRY BY SUNRISE SUNDAY.
THE DRIER AIR BEHIND THIS WEAK COLD FRONT WILL RESULT IN FAIR AND
WARM WEATHER SUNDAY AND SUNDAY NIGHT.
HIGHS SATURDAY WILL BE IN THE UPPER 60S AND 70S. LOWS SATURDAY
NIGHT GENERALLY 50 TO 60. HIGHS SUNDAY 75 TO 85. LOWS SUNDAY NIGHT IN
THE UPPER 40S AND 50S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
THE LONG TERM PERIOD WILL BEGIN SOMEWHAT UNSETTLED...BEFORE FAIR
WEATHER AND COOLER TEMPERATURES DOMINATE FOR THE BULK OF THE
REMAINDER OF THE LONG TERM.
FOR MON...A SHARP UPPER LEVEL RIDGE WILL CREST OVER THE REGION
BEFORE MOVING OFF THE NEW ENGLAND COAST LATE IN THE DAY. AT THE
SFC...A BACKDOOR COLD FRONTAL BOUNDARY SHOULD START OUT ACROSS
CENTRAL NYS...POSSIBLY EXTREME WESTERN AREAS OF THE REGION IN THE
MORNING. THIS BOUNDARY SHOULD WEAKEN...BEFORE DRIFTING BACK EAST
LATER IN THE DAY. ALSO...A MUCH STRONGER COLD FRONT WILL BE
APPROACHING FROM THE GREAT LAKES REGION. IT APPEARS THAT SHOWERS
SHOULD SLOWLY EXPAND EASTWARD ACROSS THE REGION DURING THE DAY.
HOWEVER...GIVEN THE SHARPNESS OF THE UPPER LEVEL RIDGE...IT IS QUITE
POSSIBLE THAT AREAS EAST OF THE HUDSON RIVER REMAIN DRY THROUGH
SUNSET. SO...WILL ONLY GRADUALLY INCREASE POPS INTO THE CHC RANGE
FOR WESTERN AREAS...AND MAINLY SLIGHT CHC FOR EASTERN AREAS BY LATE
IN THE DAY...WITH MAINLY DRY CONDITIONS FOR ALL AREAS IN THE
MORNING. TEMPERATURES WILL BE WARMEST ACROSS THE SOUTHERN
ADIRONDACKS AND WESTERN MOHAWK RIVER VALLEY...WHERE TEMPS NEAR 80
ARE EXPECTED. ELSEWHERE...A MARINE MODIFIED AIR MASS SHOULD RESULT
IN SLIGHTLY COOLER TEMPS FURTHER SOUTH AND EAST...WITH GENERALLY 70S
FOR VALLEYS...AND UPPER 60S/LOWER 70S ACROSS HIGHER ELEVATIONS.
MON NT-TUE...THE COLD FRONT ACROSS THE GREAT LAKES REGION SHOULD
SLOWLY SWING EAST ACROSS THE REGION. THIS SHOULD RESULT IN SOME
ROUNDS OF SHOWERS AND POSSIBLE THUNDERSTORMS. THE BEST CHANCE FOR
SIGNIFICANT RAINFALL WILL BE ACROSS THE SOUTHERN ADIRONDACKS AND
WESTERN MOHAWK VALLEY...WHICH WILL BE CLOSER TO THE PASSING UPPER
LEVEL DYNAMICS. SHOWERS MAY TEND TO BECOME MORE SCATTERED FOR AREAS
SOUTH AND EAST OF ALBANY. DEPENDING ON THE SPEED OF THE
FRONT...SHOWERS MAY TEND TO TAPER OFF FROM NW TO SE TUE AFTERNOON.
ALTHOUGH MID/UPPER LEVEL WINDS WILL STRENGTHEN...AT THIS TIME...MID
LEVEL LAPSE RATES DO NOT APPEAR VERY STRONG...SO AT LEAST AT THIS
TIME RANGE...IT APPEARS THAT THE OVERALL THREAT FOR WIDESPREAD
STRONG/SEVERE THUNDERSTORMS SHOULD BE LOW. MON NT/TUE AM MIN TEMPS
SHOULD BE MILD...MAINLY IN THE 50S TO LOWER 60S. TUE MAX TEMPS ARE
TRICKY...DEPENDING ON HOW MUCH SUN CAN BREAK OUT. ASSUMING CLOUDS
REMAIN FAIRLY WIDESPREAD...CURRENT FORECAST MAX TEMPS ARE IN THE 70-
75 RANGE IN VALLEYS AND 60S ACROSS HIGHER ELEVATIONS. HOWEVER...IF
THE FRONT SLOWS DOWN AND SOME BREAKS CAN DEVELOP...MUCH WARMER MAXES
COULD OCCUR.
TUE NT-FRI...LARGE HIGH PRESSURE SHOULD SLOWLY BUILD ACROSS THE
REGION FROM THE GREAT LAKES. MOST LONG TERM GUIDANCE SUGGESTS
ANOMALOUSLY COOL MID/UPPER LEVEL HEIGHTS AND CORRESPONDING H925-850
TEMPS. THERE COULD BE SPOTTY SHOWERS/SPRINKLES IN ASSOCIATION WITH
THE UPPER LEVEL COLD POOL AND EVEN SOME WEAK LAKE EFFECT PROCESSES
FOR TUE NT-WED ACROSS THE SOUTHWEST ADIRONDACKS. OTHERWISE...TEMPS
WILL BE QUITE COOL WED...WITH MAXES ONLY REACHING 60-65 IN
VALLEYS...AND 50S FOR MOST HIGHER ELEVATIONS...ALTHOUGH SOME OF THE
HIGHEST PEAKS OF THE SOUTHERN ADIRONDACKS AND SOUTHERN VT MAY ONLY
REMAIN IN THE 40S. OVERNIGHT MIN TEMPS FOR TUE NT/WED AM WILL MAINLY
BE IN THE 40S TO LOWER 50S. FOR WED NT/THU AM...MIN TEMPS SHOULD BE
EVEN COOLER...WITH 30S ACROSS THE WESTERN ADIRONDACKS...AND 40S
ELSEWHERE. THERE COULD BE SOME FROST ACROSS PORTIONS OF THE SOUTHERN
ADIRONDACKS...WHERE THE GROWING SEASON BEGINS MAY 21. THU AND FRI
MAX TEMPS SHOULD WARM SLIGHTLY...WITH LOWER 70S IN VALLEYS AND 60S
ACROSS HIGHER ELEVATIONS. MIN TEMPS FOR THU NT/FRI AM SHOULD FALL
INTO THE 40S FOR MOST AREAS.
&&
.AVIATION /05Z SATURDAY THROUGH WEDNESDAY/...
A WARM FRONT WILL APPROACH FROM THE SOUTHWEST LATER TONIGHT AND
SATURDAY MORNING...PRECEDED AND ACCOMPANIED BY SOME SHOWERS.
GENERALLY VFR CONDITIONS ARE EXPECTED OVER THE NEXT 24 HOURS
ENDING 00Z/SUN...DESPITE SOME MID LEVEL CLOUDS AND SHOWERS
TONIGHT. DEPENDING ON IF MEASURABLE RAIN ACTUALLY FALLS...THERE
COULD BE ENOUGH MOISTENING OF THE BOUNDARY LAYER BETWEEN 10Z-
14Z/SAT TO PRODUCE MVFR CIGS AND VSBYS...BUT THIS APPEARS TO BE A
RATHER LOW PROBABILITY. THE BEST CHANCE THAT THIS OCCURS WOULD BE
KGFL.
AFTER THE WARM FRONT PASSES SAT MORNING...AN ISOLATED SHOWER OR
THUNDERSTORM COULD DEVELOP LATER IN THE AFTERNOON. THE BEST CHANCE
OF THIS WOULD BE AT KPOU...BUT OVERALL AREAL COVERAGE AND
PROBABILITY IS TOO LOW TO MENTION IN TAFS AT THIS TIME.
OUTLOOK...
SATURDAY NIGHT: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA...TSRA.
SUNDAY: NO OPERATIONAL IMPACT. NO SIG WX.
SUNDAY NIGHT: NO OPERATIONAL IMPACT. NO SIG WX.
MONDAY: LOW OPERATIONAL IMPACT. SLIGHT CHANCE OF SHRA.
MONDAY NIGHT: MODERATE OPERATIONAL IMPACT. CHANCE OF SHRA...TSRA.
TUESDAY: MODERATE OPERATIONAL IMPACT. LIKELY SHRA...TSRA.
TUESDAY NIGHT: ISOLATED SHRA.
WEDNESDAY: NO OPERATIONAL IMPACT. NO SIG WX.
&&
.FIRE WEATHER...
A WARM FRONT AND WEAK LOW PRESSURE SYSTEM WILL MOVE INTO THE REGION
TONIGHT AND DRIFT ACROSS THE AREA SATURDAY WITH SHOWERS AND ISOLATED
THUNDERSTORMS. HIGH PRESSURE WILL CREST OVER THE REGION SUNDAY...
AND SLIDE OFFSHORE SUNDAY NIGHT WITH FAIR AND MAINLY DRY AND WARM
WEATHER SUNDAY INTO MONDAY.
WINDS WILL BE LIGHT AND VARIABLE TONIGHT AND RH VALUES WILL BE 90
TO 100 PERCENT. WINDS WILL BECOME SOUTHWEST SATURDAY AT 10 TO 15
MPH WITH RH 50 TO 60 PERCENT. RAINFALL TONIGHT AND SATURDAY MAY
PRODUCE UP TO A QUARTER TO A THIRD OF INCH. DRY WEATHER IS
EXPECTED SUNDAY AND MONDAY.
&&
.HYDROLOGY...
THE NEXT CHANCE OF SHOWERS WILL BE TONIGHT INTO SATURDAY...WITH
RAINFALL AMOUNTS EXPECTED TO BE AROUND A QUARTER TO A THIRD OF AN
INCH. THIS WILL HAVE LITTLE IMPACT ON AREA RIVERS AND STREAMS.
ONLY ISOLATED TO SCATTERED SHOWERS ARE EXPECTED SATURDAY AFTERNOON
AND NIGHT...WITH MAINLY DRY WEATHER EXPECTED FOR SUNDAY.
ANOTHER ROUND OF RAIN IS LIKELY LATE MONDAY INTO TUESDAY WITH THE
POTENTIAL FOR ANOTHER QUARTER TO THIRD OF AN INCH.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...IAA/GJM
NEAR TERM...IAA/KL/GJM/LFM
SHORT TERM...GJM
LONG TERM...KL
AVIATION...KL
FIRE WEATHER...GJM
HYDROLOGY...GJM
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
400 PM EDT SAT MAY 16 2015
.SYNOPSIS...
A WEAK COLD FRONT IS FORECAST TO MOVE THROUGH OUR AREA SUNDAY INTO
SUNDAY NIGHT. THE NEXT LOW PRESSURE SYSTEM CURRENTLY NEAR THE ROCKIES
IS EXPECTED TO PROGRESS EASTWARD ACROSS THE GREAT LAKES REGION,
SENDING A COLD FRONT THROUGH OUR AREA TUESDAY INTO TUESDAY NIGHT.
HIGH PRESSURE WILL THEN GRADUALLY BUILD EAST INTO OUR REGION FROM
MIDWEEK THROUGH FRIDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A DISORGANIZED AREA OF CONVECTION HAS BEEN STEADILY MOVING EASTWARD
THIS AFTERNOON THROUGH CENTRAL PENNSYLVANIA WHERE BULK SHEAR VALUES
ARE LESS THAN 25 KNOTS. AS THIS LINE MOVES CLOSER TO OUR REGION IT
WILL BEGIN TO INGEST MORE UNSTABLE AIR WITH BETTER BULK SHEAR IN
PLACE ALLOWING FOR SOMEWHAT MORE ORGANIZATION AND LONGEVITY.
EXPECTING THESE STORMS TO MOVE INTO OUR WESTERN ZONES OVER THE NEXT
COUPLE OF HOURS. FORECAST SOUNDINGS STILL SHOW LONG THIN CAPE
PROFILES WITH SOME DRY AIR IN THE MID-LEVELS. LATEST RUC DCAPE
VALUES ARE AROUND 800 TO 1000J/KG WITH STRONG TO ISOLATED SEVERE
WIND GUSTS THE MAIN THREAT TO ANY OF THESE STORMS. VERY HEAVY
RAINFALL IS ALSO EXPECTED AS THEY PUSH THROUGH WITH PWAT VALUES
RUNNING AROUND THE 99TH PERCENTILE FOR MID-MAY. THIS COUPLED WITH
VERY DRY CONDITIONS SHOULD ALLOW FOR MORE EFFICIENT RUNOFF TO OCCUR
WITH PONDING ON ROADWAYS AND POOR DRAINAGE LOCATIONS. FORTUNATELY
THE MEAN STEERING FLOW OF THESE STORMS IS ALLOWING THEM TO MOVE
RELATIVELY QUICKLY, AROUND 30 KNOTS TOWARDS THE EAST.
ONCE THESE STORMS EITHER PUSH OFF THE COAST OF BECOME ELEVATED IN
NATURE WITH THE LOSS OF DAYTIME HEATING MORE SCATTERED SHOWER
ACTIVITY IS EXPECTED THROUGH MOST OF THE LATE EVENING HOURS BEFORE
WE DRY OUT SOME. VERY MUGGY CONDITIONS WILL EXIST TONIGHT WITH AMPLE
MOISTURE IN THE LOW-LEVELS. PATCHY FOG IS POSSIBLE AS THE WINDS
DECOUPLE AND BECOME LIGHT AND VARIABLE.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
ALMOST A CARBON COPY OF SATURDAY IN TERMS OF THE SHOWER/CONVECTION
THREAT DURING THE DAY...MAYBE NOT AS WIDESPREAD. WE WILL HAVE THE
MOISTURE IN PLACE WITH ANOTHER WELL ABOVE AVERAGE TEMPERATURE
FORECAST. ONE OF THE BIGGEST QUESTIONS IS THE POTENTIAL LACK OF
BETTER SURFACE BASED INSTABILITY WITH A PERSISTENT STRATOCU DECK IN
PLACE...MAYBE SOME BREAKS POSSIBLE AS THE WINDS VEER MORE TOWARDS
THE WEST DURING THE AFTERNOON. TEMPERATURES MAY END UP A TAD COOLER
WITH THE AMOUNT OF MOISTURE TRAPPED UNDER THE LOW-LEVEL INVERSION,
BUT A WARMER STARTING POINT SHOULD YIELD LOW-80S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
DESPITE STARTING OUT UNDER THE AXIS OF AN UPPER LEVEL SHORTWAVE
RIDGE...THERE LOOK TO BE PLENTY OF OPPORTUNITIES FOR RAIN, AT
LEAST TO BEGIN THE LONG TERM PERIODS.
SUNDAY NIGHT...SHORTWAVE RIDGE PIVOTS OVERHEAD, WHILE AT THE
SURFACE, THE WEAK COLD FRONT CONTINUES TO SLIDE SOUTH OVER THE
REGION. THE COMBINATION OF MID AND UPPER LEVEL SUBSIDENCE, ALONG
WITH A NOCTURNAL INVERSION SHOULD HELP TO SUPPRESS OVERNIGHT
CONVECTION. THEREFORE, STAYED CLOSE TO THE PREVIOUS FORECAST WITH
PRECIP CHANCES DROPPING FROM 20 TO 50 PERCENT IN THE EVENING TO 10
TO 20 PERCENT AFTER MIDNIGHT.
MONDAY INTO TUESDAY...SURFACE LOW STILL EXPECTED TO TRACK ACROSS
THE GREAT LAKES REGION, WHILE IN THE MID AND UPPER LEVELS, THE
RIDGE SHIFTS OFF SHORE. PERSISTENT EASTERLY FLOW ON MONDAY
RESULTING IN LOW CLOUDS, MAY LIMIT SURFACE BASED INSTABILITY, BUT
ELEVATED INSTABILITY IS POSSIBLE. THEREFORE, INCLUDED THUNDERSTORM
MENTION ACROSS THE REGION, THOUGH WOULD EXPECT MOSTLY STRATIFORM
RAIN OR SHOWERS ON MONDAY. ON TUESDAY HOWEVER, WINDS SHIFT TO
SOUTHERLY AND SOUTHWESTERLY AS A PRE FRONTAL TROUGH ARRIVES
TUESDAY AFTERNOON. THE COLD FRONT SHOULD ARRIVE TUESDAY
EVENING/OVERNIGHT. THERE ALSO APPEARS TO BE SUBSTANTIAL SPEED
SHEAR (20 TO 35 KT) THROUGH THE DAY. THERE ARE A FEW POTENTIAL
LIMITATIONS TO CONVECTION THOUGH, PRIMARILY MEAGER LAPSE RATES
ABOVE THE BOUNDARY LAYER. PRECIPITABLE WATER VALUES SHOULD BE
WELL ABOVE NORMAL, AND THE WARM CLOUD LAYER IS EXPECTED TO BE
QUITE DEEP. AND WHILE FORECAST STORM MOTIONS SHOULD BE AROUND 20
TO 25 KT, THERE IS THE POTENTIAL FOR TRAINING STORMS IF THE PRE
FRONTAL TROUGH SERVES AS A FOCUS FOR CONVECTIVE INITIATION.
THEREFORE, WILL ADD MENTION IN THE HWO OF HEAVY RAIN THREAT.
WEDNESDAY THROUGH SATURDAY...FRONT CLEARS OUT QUICKLY BY EARLY
WEDNESDAY MORNING, LEAVING THE REGION UNDER A MOSTLY DRY PATTERN
AS A SURFACE HIGH IS EXPECTED TO BUILD IN OVER MUCH OF THE
NORTHEAST. A FEW CAVEATS, HOWEVER. FIRST, A PAIR OF SHORTWAVE
TROUGHS ON THE BACK SIDE OF THE DEPARTING UPPER LEVEL TROUGH MAY
DIG OVER OUR REGION, BUT THE TIMING OF THE TROUGHS IS UNCERTAIN,
AND LOW LEVEL MOISTURE MAY BE LIMITED WITH PERSISTENT DOWN SLOPE
FLOW. SECOND, BOTH THE GFS AND ECMWF SHOW A COASTAL LOW DEVELOPING
OVER THE CAROLINA/VIRGINIA COASTS BY FRIDAY. DEPENDING ON HOW FAR
NORTH THIS DEVELOPS, IT COULD RESULT IN PRECIP ACROSS THE DELMARVA
PENINSULA AND FAR SOUTHERN NJ.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THIS EVENING - TONIGHT...MOSTLY VFR WITH SOME MVFR/IFR SHOWERS AND
THUNDERSTORMS POSSIBLE THIS EVENING. STILL THINKING MOST OF THE
THUNDER ACTIVITY OCCURS AROUND 20 TO 00Z THIS EVENING FROM WEST TO
EAST. AFTERWARDS LINGERING SHOWERS ARE POSSIBLE ALLOWING CONDITIONS
TO DETERIORATE TOWARDS MVFR AFTER MIDNIGHT...LOW CONFIDENCE ON MVFR
CONDITIONS TONIGHT.
SUNDAY...ANY MVFR RESTRICTIONS SHOULD LIFT/BURN OFF BY LATE MORNING
ALLOWING FOR MORE VFR CONDITIONS. CONTINUED SOUTHWESTERLY FLOW WILL
KEEP MOISTURE STREAMING INTO THE REGION SO WE MAY NOT BREAK OUT MUCH
DURING THE DAY. MORE SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE DURING THE AFTERNOON HOURS.
OUTLOOK...
SUNDAY NIGHT INTO MONDAY...WIDESPREAD MVFR AND LOCALIZED IFR
CONDITIONS WITH LOW CLOUDS AND SHOWERS POSSIBLE FOR MUCH OF THE
PERIOD. CHANCE FOR THUNDERSTORMS MONDAY AFTERNOON AND EVENING.
TUESDAY...THUNDERSTORMS LIKELY. MVFR AND LOCALIZED IFR CONDITIONS
EXPECTED TO CONTINUE.
WEDNESDAY AND THURSDAY...VFR CONDITIONS EXPECTED.
&&
.MARINE...
TONIGHT - SUNDAY...SUB-SCA CONDITIONS ACROSS THE WATERS EXPECTED.
SOUTHERLY FLOW WILL CONTINUE THROUGH SUNDAY ALLOWING SEAS TO BUILD
UPWARDS OF 4 FEET BY SUNDAY AFTERNOON. WITH COLDER THAN NORMAL WATER
TEMPERATURES AND A WARMER AIRMASS IN PLACE EXPECTING THE AMOUNT OF
MIXING TO BE KEPT TO A MINIMUM...LESS THAN 20 KNOTS.
OUTLOOK...
MONDAY AND TUESDAY...SUB SCA CONDITIONS LIKELY. HOWEVER, A FEW
GUSTS ABOVE 20 KT ARE POSSIBLE ON MONDAY ON THE OCEAN WATERS, AND
HIGHER GUSTS WILL BE POSSIBLE IN THE VICINITY OF ANY
THUNDERSTORMS.
WEDNESDAY AND THURSDAY...WINDS AND SEAS SHOULD REMAIN BELOW SCA
CRITERIA.
&&
.RIP CURRENTS...
THE RISK FOR RIP CURRENTS IS BORDERLINE LOW TO MODERATE FOR THE
NJ COAST ON SATURDAY AFTERNOON.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JOHNSON
NEAR TERM...HEAVENER
SHORT TERM...HEAVENER
LONG TERM...JOHNSON
AVIATION...HEAVENER/JOHNSON
MARINE...HEAVENER/JOHNSON
RIP CURRENTS...O`HARA
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
228 PM EDT SAT MAY 16 2015
.SYNOPSIS...
18Z WATER VAPOR AND H4 RAP ANALYSIS SHOW AN AMPLIFIED UPPER LEVEL
PATTERN OVER THE CONUS TODAY. DEEP AND POTENT UPPER TROUGH IS
SPINNING OVER THE INTERMOUNTAIN WEST/WESTERN PLAINS...WITH
DOWNSTREAM STRONG RIDGING ALOFT OVER THE EASTERN THIRD OF THE
NATION. WV IMAGERY SHOWS A STRONG SHORTWAVE ROUNDING THE BASE OF
THE WESTERN TROUGH AND ABOUT TO EJECT NORTHEASTWARD OVER THE
CENTRAL PLAINS. THIS ENERGY IS FORECAST TO BRING A POTENTIAL
SIGNIFICANT SEVERE WEATHER OUTBREAK TO PARTS OF TEXAS/OK/KS LATER
TODAY. WHILE THIS WEATHER SYSTEM AND ITS ASSOCIATED ORGANIZED
SEVERE WEATHER THREAT WILL STAY WELL TO OUR NORTHWEST THIS
WEEKEND...WE IN WEST-CENTRAL AND SOUTHWEST FLORIDA WILL BE
DEALING WITH MORE OF OUR OWN LATE DAY SEA-BREEZE STORMS. MORE INFO
ON OUR THUNDERSTORM THREAT IN THE SHORT TERM DISCUSSION BELOW.
AT THE SURFACE...ATLANTIC HIGH PRESSURE CONTINUES TO RIDGE BACK TO
THE WEST INTO THE GA/CAROLINA COAST...PROVIDING OUR REGION WITH A
GENERAL EAST TO SOUTHEAST LOW LEVEL FLOW. SIMILAR TO PREVIOUS
DAYS...THIS EASTERLY SYNOPTIC FLOW WILL FAVOR THUNDERSTORM
DEVELOPMENT ALONG THE FLORIDA WEST COAST SEA-BREEZE DUE TO THE
ADDED CONVERGENCE AND EVENTUAL ARRIVAL/COLLISION OF THE EAST
COAST SEA- BREEZE BOUNDARY.
&&
.SHORT TERM...
REST OF TODAY...WITHIN THE LARGE SCALE PRESSURE GRADIENT ON THE
SOUTHERN PERIPHERY OF THE ATLANTIC RIDGE TO OUR NORTH...WE CAN
ANALYZE A WEAK INVERTED TROUGH/CONVERGENCE ZONE ALONG THE
SOUTHEAST FL COAST. SCATTERED SHOWERS BEGAN MIGRATING WESTWARD
FROM THIS FEATURE INTO THE SOUTH-CENTRAL ZONES
(HIGHLANDS/HARDEE/DESOTO) DURING THE EARLY AFTERNOON...AND NOW
MOVING OVER TOWARD THE PUNTA GORDA/FORT MYERS AREA. SO...A FEW
SHOWERS AROUND FOR THE SOUTHERN ZONES FROM THIS ACTIVITY THROUGH
MID AFTERNOON...BUT THE MAIN CONVECTIVE DEVELOPMENT IS STILL NOT
EXPECTED UNTIL LATER IN THE AFTERNOON/EARLY EVENING HOURS. BEFORE
THE EXPECTED CONVECTIVE BURST...MUCH OF THE REGION FROM THE I-4
CORRIDOR NORTHWARD WILL SEE A MIX OF SUN AND CLOUDS WITH
TEMPERATURES INTO THE 80S.
FORECASTING SEA-BREEZE THUNDERSTORMS IS NEVER A PERFECT SCIENCE...
BUT HERE IS THE BREAKDOWN LEADING TO THE CURRENT FORECAST. WE START
WITH THE SYNOPTIC LOW LEVEL (1000-700MB) FLOW...WHICH TODAY IS
MODERATE FROM THE EAST/SOUTHEAST. THIS FLOW REGIME DURING THE WARM
SEASON FAVORS LATE DAY THUNDERSTORM DEVELOPMENT ALONG THE FLORIDA
WEST COAST...WITH DRIER CONDITIONS BY LATE AFTERNOON FOR THE FLORIDA
EAST COAST. THE WEST COAST IS FAVORED DUE TO THE ENHANCED
CONVERGENCE OF THE LARGE SCALE FLOW HEADING WESTWARD...AND THE WEST
COAST SEA-BREEZE TRYING TO MOVE EAST. EVENTUALLY THE EAST COAST SEA-
BREEZE...SPED ALONG BY THE LARGE SCALE FLOW ARRIVES AT THE I-75
CORRIDOR AND FURTHER ENHANCES THE LOW LEVEL FOCUS/CONVERGENCE.
ALOFT...THERE IS NOT REALLY ANY SIGNIFICANT HOSTILE LAYER TOWARD
DEEP CONVECTION...WITH MINIMUM THETAE VALUES NO LOWER THAN AROUND
320K (FAIRLY TYPICAL FOR MID MAY).
THE CURRENT FORECAST FAVORS THE HIGHEST RAIN CHANCES LATE
AFTERNOON/EVENING FROM TAMPA BAY SOUTHWARD DUE TO THE FACT THAT THE
FLOW JUST ALOFT OFF THE SURFACE SEEMS TO BE A BIT STRONGER FOR THE
NATURE COAST...AND IS BORDERLINE STRONG ENOUGH TO PREVENT AN
ORGANIZED SEA-BREEZE...OR TO KEEP IT SUPPRESSED JUST OFFSHORE.
LIGHTER FLOW FURTHER SOUTH SHOULD ALLOW SOME INLAND PENETRATION OF
THE SEA-BREEZE CIRCULATION SO THAT THE MORE EFFICIENT LOW LEVEL
FOCUS ZONE TO ENHANCE LIFT APPEARS TO SET UP FROM PASCO/PINELLAS
COUNTIES SOUTHWARD. THERE IS ACTUALLY VERY GOOD AGREEMENT AMONG THE
HIRES CONVECTION ALLOWING GUIDANCE FROM NCEP AND LOCAL RUNS TO
SUPPORT THIS SCENARIO. IN FACT...THE LAST FEW RUNS OF THE HRRR HAVE
BEEN FOCUSING MAINLY FROM MANATEE COUNTY SOUTHWARD. SINCE...THE
HIRES GUIDANCE ARE SUBJECT TO INFLUENCE FROM THEIR OWN EARLIER
CONVECTION...AND THE PARAMETERIZED MODELS ARE STILL SHOWING
DEVELOPMENT A BIT FURTHER NORTH...HAVE INCLUDED THE TAMPA BAY/PASCO
AREA IN THE LIKELY RAIN/THUNDER CHANCES. WILL SEE HOW ALL THIS WORKS
OUT AS WE GET LATER INTO THE DAY...BUT BASED ON ALL AVAILABLE INFO
AND PATTERN RECOGNITION...FEEL THIS IS THE BEST FORECAST.
HAVE ALSO BEEN FAIRLY IMPRESSED WITH THE GENERAL UPDRAFT VELOCITY
VALUES OUT OF THE HRRR FOR LATER TODAY. PEAK VALUES ALONG THE SUN
COAST TO THE SOUTH OF TAMPA BAY HAVE BEEN IN THE 14-18M/S
RANGE...WHICH IS FAIRLY SUBSTANTIAL FOR LOW SHEAR PULSE
CONVECTION. WITH THIS IN MIND WILL NEED TO BE MINDFUL OF PRECIP
LOADING AND DOWNBURST POTENTIAL WITH STRONGER CELLS. ALSO...THE
POTENTIAL FOR SOME EFFICIENT LIGHTNING PRODUCERS IS ALSO THERE.
WHAT IS LEFT OF THE STORMS PUSH OFFSHORE INTO THE COASTAL WATERS BY
LATE EVENING...FOLLOWED BY A GENERALLY QUIET...DRY AND SEASONABLY
WARM OVERNIGHT PERIOD.
SUNDAY... WE SEE ONE MORE DAY WITH THIS BROKEN RECORD PATTERN OF
EASTERLY SYNOPTIC FLOW BEFORE THE PATTERN BEGINS TO TRANSITION.
ONE THING ADVERTISED BY THE CURRENT MODEL SUITE...IS A MORE
UNIFORM LIGHT FLOW ABOVE THE SURFACE FOR THE AFTERNOON
HOURS...RESULTING IN A MORE UNIFORM ORGANIZATION TO THE SEA-BREEZE
ALONG OUR COASTS. THEREFORE...AFTER A QUIET MORNING AND EARLY
AFTERNOON...YET ANOTHER ROUND OF LATE DAY STORMS IS ANTICIPATED
ALONG THE I-75 CORRIDOR. AS IT STANDS NOW...APPEARS WE SHOULD SEE
A SCATTERING OF SHOWERS/STORMS PROGRESS FROM EAST TO WEST ACROSS
THE FORECAST AREA ALONG THE EAST COAST SEA BREEZE DURING THE
EARLY/MID AFTERNOON...WITH CONVECTION RAMPING UP TO NUMEROUS
THUNDERSTORMS ALONG AND INSIDE THE I-75 CORRIDOR AFTER AROUND 400
PM.
&&
.LONG TERM (MONDAY THROUGH NEXT SATURDAY)...ALOFT - RIDGING GENERALLY
DOMINATES THE GULF AND FL...ALTHOUGH IT BRIEFLY WEAKENS AND DRIFTS BACK
WEST MID-WEEK...AS A COUPLE OF LOWS/TROUGHS TRAVERSES THE NORTHERN TIER
OF STATES. AT THE SURFACE - HIGH PRESSURE WAS OVER CENTRAL CANADA WITH
A FRONT THAT ARCED FROM THE UPPER GREAT LAKES THROUGH THE SOUTHERN HIGH
PLAINS THEN BACK UP THROUGH THE PACIFIC NORTHWEST...THIS HIGH DROPS
DOWN INTO THE MID-MISSISSIPPI VALLEY THEN TRACKS EAST WITH THE FRONT
SAGGING IN ALONG THE AL/GA/FL BORDER BY THE END OF THE WORK WEEK AND IN
ACROSS NORTHERN FRI SAT. ATLANTIC HIGH PRESSURE...WITH AN AXIS
INITIALLY ALONG THE NORTHERN FL LINE...SINKS SOUTH WITH IT/S AXIS
SETTLING IN ACROSS CENTRAL FL THEN SOUTH FL.
THE FORECAST PHILOSOPHY WILL BE BASED ON A GENERALLY MOIST AIRMASS
IN PLACE...WITH MODEL PWAT VALUES RUNNING ABOVE 1.6 INCHES AND UP
TO NEAR 2.0 INCHES AT TIMES. THE EXCEPTION MAY BE SAT WHEN THE
FRONT SAGS INTO NORTH FL WITH SOME DRIER AIR BEHIND IT.
HOWEVER...AT THIS POINT IN THE FORECAST THE GFS BRINGS THE FRONT
INTO FL WHILE THE ECMWF HOLDS IT ON THE STATE LINE OR ABOVE. THE
SURFACE RIDGE AXIS TRACKING SOUTH WITH GRADUALLY TRANSITIONING
FLOW FROM SOUTHEASTERLY WITH SEA BREEZES TO WESTERLY BY FRI. BUT
AGAIN...BASED ON THE FASTER GFS...FLOW SHIFTS AROUND TO
NORTHEASTERLY BY THE END OF THE PERIOD. SHOWERS AND THUNDERSTORMS
WILL BE IN THE SCATTERED RANGE WITH THE HIGHEST COVERAGE SWITCHING
FROM COASTAL TO MORE INLAND THROUGH THE WORK WEEK. ABOVE NORMAL
TEMPERATURES WILL CONTINUE.
&&
.AVIATION...
CONDITIONS ARE QUIET WITH PREVAILING VFR ONGOING LATE
THIS MORNING ACROSS WEST CENTRAL AND SW FLORIDA. HOWEVER...THESE
CALM CONDITIONS ARE NOT EXPECTED TO LAST THE REMAINDER OF THE DAY.
SIMILAR TO PREVIOUS DAYS...RAPID THUNDERSTORM DEVELOPMENT IS EXPECTED
ALONG THE I-75 CORRIDOR AFTER 20Z...WITH STORMS THEN PUSHING SLOWLY
TO THE WEST. A PERIOD OF IFR OR LOWER VIS/CIGS ALONG WITH GUSTY
WINDS AND FREQUENT LIGHTING IS POSSIBLE FOR ANY TERMINAL LATER
TODAY. WILL ADD THUNDER TEMPO GROUPS WITH 18Z PACKAGE.
&&
.MARINE...
A GENERAL EAST TO SOUTHEAST WINDS FLOW WILL REMAIN IN
PLACE THROUGH SUNDAY WITH WINDS TURNING ONSHORE AT THE COAST EACH
AFTERNOON AS THE SEA BREEZE DEVELOPS. THUNDERSTORMS ARE EXPECTED
TO RAPIDLY DEVELOP NEAR THE COAST DURING THE LATE AFTERNOON AND
EVENING HOUR BOTH TODAY AND SUNDAY...THEN PUSH OFFSHORE DURING THE
NIGHTTIME HOURS. BOATERS ENJOYING THE COASTAL WATERS OF THE
FLORIDA WEST COAST SHOULD KEEP AND EYE TO THEIR EAST DURING THE
LATE DAY HOURS THIS WEEKEND...AND BE PREPARED TO SEEK SAFE HARBOR
SHOULD THREATENING WEATHER ADVANCE. HEADING THROUGH THE UPCOMING
WORK WEEK...WINDS WILL SHIFT MORE WESTERLY...KEEPING MOST OF THE
THUNDERSTORM ACTIVITY INLAND.
&&
.FIRE WEATHER...
NO FIRE WEATHER CONCERNS FOR THE NEXT FEW DAYS AS RELATIVE
HUMIDITY VALUES WILL REMAIN ABOVE CRITICAL LEVELS. LATE AFTERNOON
AND EVENING THUNDERSTORMS WILL BE MOST NUMEROUS NEAR THE COAST
FROM TAMPA BAY SOUTHWARD TODAY...THEN ALONG THE ENTIRE COASTAL
I-75 CORRIDOR FOR LATE SUNDAY. THE PATTERN WILL THEN BEGIN TO
TRANSITION TO ONE SUPPORTING LATE DAY STORMS FURTHER INLAND...WITH
DRIER CONDITIONS NEAR THE COAST.
FOG IMPACT...NO SIGNIFICANT FOG IS EXPECTED FOR THE NEXT FEW
DAYS...BUT LATE NIGHT PATCHY GROUND FOG COULD DEVELOP IN AREAS
THAT SEE RAIN DURING THE EVENING HOURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 73 89 73 89 / 30 60 50 20
FMY 72 90 72 90 / 40 60 30 30
GIF 72 90 71 91 / 10 40 10 20
SRQ 72 87 72 88 / 40 60 50 20
BKV 69 90 69 90 / 20 60 40 30
SPG 75 89 75 89 / 40 60 50 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SHORT TERM/AVIATION/FIRE WEATHER/MARINE...14/MROCZKA
LONG TERM/DECISION SUPPORT...09/RUDE
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1130 AM EDT SAT MAY 16 2015
.SYNOPSIS... 16Z WATER VAPOR AND H4 RAP ANALYSIS SHOW AN AMPLIFIED
UPPER LEVEL PATTERN OVER THE CONUS TODAY. DEEP AND POTENT UPPER
TROUGH IS SPINNING OVER THE INTERMOUNTAIN WEST/WESTERN PLAINS...WITH
DOWNSTREAM STRONG RIDGING ALOFT OVER THE EASTERN THIRD OF THE
NATION. WV IMAGERY SHOWS A STRONG SHORTWAVE ROUNDING THE BASE OF THE
WESTERN TROUGH AND ABOUT TO EJECT NORTHEASTWARD OVER THE CENTRAL
PLAINS. THIS ENERGY IS FORECAST TO BRING A POTENTIAL SIGNIFICANT
SEVERE WEATHER OUTBREAK TO PARTS OF TEXAS/OK/KS LATER TODAY. WHILE
THIS WEATHER SYSTEM AND ITS ASSOCIATED ORGANIZED SEVERE WEATHER
THREAT WILL STAY WELL TO OUR NORTHWEST THIS WEEKEND...WE IN WEST-
CENTRAL AND SOUTHWEST FLORIDA WILL BE DEALING WITH MORE OF OUR OWN
LATE DAY SEA-BREEZE STORMS. MORE INFO ON OUR THUNDERSTORM THREAT IN
THE SHORT TERM DISCUSSION BELOW.
ALREADY SEEING RAPID CUMULUS FIELD DEVELOPMENT ACROSS MUCH OF THE
PENINSULA LATE THIS MORNING...AND THIS SCT-BKN CLOUD FIELDS SHOULD
INVADE ALL OF OUR SKIES INTO THE EARLY AFTERNOON HOURS.
AT THE SURFACE...ATLANTIC HIGH PRESSURE CONTINUES TO RIDGE BACK TO
THE WEST INTO THE GA/CAROLINA COAST...PROVIDING OUR REGION WITH A
GENERAL EAST TO SOUTHEAST LOW LEVEL FLOW. SIMILAR TO PREVIOUS
DAYS...THIS EASTERLY SYNOPTIC FLOW WILL FAVOR THUNDERSTORM
DEVELOPMENT ALONG THE FLORIDA WEST COAST SEA-BREEZE DUE TO THE ADDED
CONVERGENCE AND EVENTUAL ARRIVAL/COLLISION OF THE EAST COAST SEA-
BREEZE BOUNDARY.
&&
.SHORT TERM (REST OF TODAY THROUGH SUNDAY)...
REST OF TODAY... WITHIN THE LARGE SCALE PRESSURE GRADIENT ON THE
SOUTHERN PERIPHERY OF THE ATLANTIC RIDGE TO OUR NORTH...WE CAN
ANALYZE A WEAK INVERTED TROUGH/CONVERGENCE ZONE ALONG THE SOUTHEAST
FL COAST. WILL SEE A SCATTERING OF SHOWERS BEGIN TO MIGRATE
WESTWARD FROM THIS FEATURE INTO THE SOUTH-CENTRAL ZONES
(HIGHLANDS/HARDEE/DESOTO) DURING THE EARLY AFTERNOON...AND
EVENTUALLY OVER TOWARD THE PUNTA GORDA/FORT MYERS AREA. MAY SEE A
BRIEF SHOWER FROM THIS ACTIVITY...BUT THE MAIN CONVECTIVE
DEVELOPMENT IS NOT EXPECTED UNTIL LATER IN THE AFTERNOON/EARLY
EVENING HOURS. BEFORE THE EXPECTED CONVECTIVE BURST...MUCH OF THE
REGION WILL SEE A MIX OF SUN AND CLOUDS WITH TEMPERATURES CLIMBING
THROUGH THE 80S.
FORECASTING SEA-BREEZE THUNDERSTORMS IS NEVER A PERFECT SCIENCE...
BUT HERE IS THE BREAKDOWN LEADING TO THE CURRENT FORECAST. WE START
WITH THE SYNOPTIC LOW LEVEL (1000-700MB) FLOW...WHICH TODAY IS
MODERATE FROM THE EAST/SOUTHEAST. THIS FLOW REGIME DURING THE WARM
SEASON FAVORS LATE DAY THUNDERSTORM DEVELOPMENT ALONG THE FLORIDA
WEST COAST...WITH DRIER CONDITIONS BY LATE AFTERNOON FOR THE FLORIDA
EAST COAST. THE WEST COAST IS FAVORED DUE TO THE ENHANCED
CONVERGENCE OF THE LARGE SCALE FLOW HEADING WESTWARD...AND THE WEST
COAST SEA-BREEZE TRYING TO MOVE EAST. EVENTUALLY THE EAST COAST SEA-
BREEZE...SPED ALONG BY THE LARGE SCALE FLOW ARRIVES AT THE I-75
CORRIDOR AND FURTHER ENHANCES THE LOW LEVEL FOCUS/CONVERGENCE.
ALOFT...THERE IS NOT REALLY ANY SIGNIFICANT HOSTILE LAYER TOWARD
DEEP CONVECTION...WITH MINIMUM THETAE VALUES NO LOWER THAN AROUND
320K (FAIRLY TYPICAL FOR MID MAY).
THE CURRENT FORECAST FAVORS THE HIGHEST RAIN CHANCES LATE
AFTERNOON/EVENING FROM TAMPA BAY SOUTHWARD DUE TO THE FACT THAT THE
FLOW JUST ALOFT OFF THE SURFACE SEEMS TO BE A BIT STRONGER FOR THE
NATURE COAST...AND IS BORDERLINE STRONG ENOUGH TO PREVENT AN
ORGANIZED SEA-BREEZE...OR TO KEEP IT SUPPRESSED JUST OFFSHORE.
LIGHTER FLOW FURTHER SOUTH SHOULD ALLOW SOME INLAND PENETRATION OF
THE SEA-BREEZE CIRCULATION SO THAT THE MORE EFFICIENT LOW LEVEL
FOCUS ZONE TO ENHANCE LIFT APPEARS TO SET UP FROM PASCO/PINELLAS
COUNTIES SOUTHWARD. THERE IS ACTUALLY VERY GOOD AGREEMENT AMONG THE
HIRES CONVECTION ALLOWING GUIDANCE FROM NCEP AND LOCAL RUNS TO
SUPPORT THIS SCENARIO. IN FACT...THE LAST FEW RUNS OF THE HRRR HAVE
BEEN FOCUSING MAINLY FROM MANATEE COUNTY SOUTHWARD. SINCE...THE
HIRES GUIDANCE ARE SUBJECT TO INFLUENCE FROM THEIR OWN EARLIER
CONVECTION...AND THE PARAMETERIZED MODELS ARE STILL SHOWING
DEVELOPMENT A BIT FURTHER NORTH...HAVE INCLUDED THE TAMPA BAY/PASCO
AREA IN THE LIKELY RAIN/THUNDER CHANCES. WILL SEE HOW ALL THIS WORKS
OUT AS WE GET LATER INTO THE DAY...BUT BASED ON ALL AVAILABLE INFO
AND PATTERN RECOGNITION...FEEL THIS IS THE BEST FORECAST.
HAVE ALSO BEEN FAIRLY IMPRESSED WITH THE GENERAL UPDRAFT VELOCITY
VALUES OUT OF THE HRRR FOR LATER TODAY. PEAK VALUES SOUTH OF TAMPA
BAY HAVE BEEN IN THE 15-20M/S RANGE...WHICH IS FAIRLY SUBSTANTIAL
FOR LOW SHEAR PULSE CONVECTION. WITH THIS IN MIND WILL NEED TO BE
MINDFUL OF PRECIP LOADING AND DOWNBURST POTENTIAL WITH STRONGER
CELLS. ALSO...THE POTENTIAL FOR SOME EFFICIENT LIGHTNING PRODUCERS
IS ALSO THERE.
WHAT IS LEFT OF THE STORMS PUSH OFFSHORE INTO THE COASTAL WATERS BY
LATE EVENING...FOLLOWED BY A GENERALLY QUIET...DRY AND SEASONABLY
WARM OVERNIGHT PERIOD.
SUNDAY... WE SEE ONE MORE DAY WITH THIS BROKEN RECORD PATTERN OF
EASTERLY SYNOPTIC FLOW. ONE THING ADVERTISED BY THE CURRENT MODEL
SUITE...IS A MORE UNIFORM LIGHT FLOW ABOVE THE SURFACE FOR THE
AFTERNOON HOURS...RESULTING IN A MORE UNIFORM ORGANIZATION TO THE
SEA-BREEZE ALONG OUR COASTS. THEREFORE...AFTER A QUIET MORNING AND
EARLY AFTERNOON...YET ANOTHER ROUND OF LATE DAY STORMS IS
ANTICIPATED ALONG THE I-75 CORRIDOR. AS IT STANDS NOW...APPEARS WE
SHOULD SEE A SCATTERING OF SHOWERS/STORMS PROGRESS FROM EAST TO WEST
ACROSS THE FORECAST AREA ALONG THE EAST COAST SEA BREEZE DURING THE
EARLY/MID AFTERNOON...WITH CONVECTION RAMPING UP TO NUMEROUS
THUNDERSTORMS ALONG AND INSIDE THE I-75 CORRIDOR AFTER AROUND 400 PM.
THE SYNOPTIC PATTERN FINALLY BEGINS TO TRANSITION TO A MORE WESTERLY
FLOW REGIME EARLY NEXT WEEK...WHICH SHOULD SHIFT THE HIGHER RAIN
CHANCES AWAY FROM THE COAST TOWARD THE INLAND AREAS/FL EAST COAST.
&&
.AVIATION... CONDITIONS ARE QUIET WITH PREVAILING VFR ONGOING LATE
THIS MORNING ACROSS WEST CENTRAL AND SW FLORIDA. HOWEVER...THESE
CALM CONDITIONS ARE NOT EXPECTED TO LAST THE REMAINDER OF THE DAY.
SIMILAR TO PREVIOUS DAYS...RAPID THUNDERSTORM DEVELOPMENT IS EXPECTED
ALONG THE I-75 CORRIDOR AFTER 20Z...WITH STORMS THEN PUSHING SLOWLY
TO THE WEST. A PERIOD OF IFR OR LOWER VIS/CIGS ALONG WITH GUSTY
WINDS AND FREQUENT LIGHTING IS POSSIBLE FOR ANY TERMINAL LATER
TODAY. WILL ADD THUNDER TEMPO GROUPS WITH 18Z PACKAGE.
&&
.MARINE...
A GENERAL EAST TO SOUTHEAST WINDS FLOW WILL REMAIN IN
PLACE THROUGH SUNDAY WITH WINDS TURNING ONSHORE AT THE COAST EACH
AFTERNOON AS THE SEA BREEZE DEVELOPS. THUNDERSTORMS ARE EXPECTED
TO RAPIDLY DEVELOP NEAR THE COAST DURING THE LATE AFTERNOON AND
EVENING HOUR BOTH TODAY AND SUNDAY...THEN PUSH OFFSHORE DURING THE
NIGHTIME HOURS. BOATERS ENJOYING THE COASTAL WATERS OF THE FLORIDA
WEST COAST SHOULD KEEP AND EYE TO THEIR EAST DURING THE LATE DAY
HOURS THIS WEEKEND...AND BE PREPARED TO SEEK SAFE HARBOR SHOULD
THREATENING WEATHER ADVANCE. HEADING THROUGH THE UPCOMING WORK
WEEK...WINDS WILL SHIFT MORE WESTERLY...KEEPING MOST OF THE
THUNDERSTORM ACTIVITY INLAND.
&&
.FIRE WEATHER...
NO FIRE WEATHER CONCERNS FOR THE NEXT FEW DAYS AS RELATIVE
HUMIDITY VALUES WILL REMAIN ABOVE CRITICAL LEVELS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 89 73 89 73 / 60 30 60 20
FMY 91 72 90 72 / 70 40 60 20
GIF 90 72 90 71 / 30 10 50 10
SRQ 88 72 88 72 / 70 40 60 20
BKV 90 70 89 69 / 50 20 60 10
SPG 89 75 89 75 / 60 40 60 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE/AVIATION/FIRE WX...MROCZKA
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
1011 PM EDT SUN MAY 17 2015
.SYNOPSIS...
DRY WEATHER WILL CONTINUE THROUGH TONIGHT WITH HIGH PRESSURE AT
THE SURFACE AND ALOFT. THE CHANCE FOR RAIN WILL INCREASE MONDAY
AFTERNOON AHEAD OF AN APPROACHING COLD FRONT SCHEDULED TO CROSS
THE AREA TUESDAY. TEMPERATURES WILL BE ABOVE NORMAL THROUGH THE
WEEK.
&&
.NEAR TERM /UNTIL 7 AM MONDAY MORNING/...
DRY WEATHER WILL CONTINUE THROUGH TONIGHT AS AN UPPER-LEVEL RIDGE
HOLDS ACROSS THE REGION AND SURFACE HIGH PRESSURE CENTERED OVER
THE WESTERN ATLANTIC RIDGES INTO THE SOUTHEASTERN STATES. DEEPER
MOISTURE WILL REMAIN JUST TO OUR WEST AND NORTH. LOWS TONIGHT
WILL BE MAINLY IN THE MID 60S...EXCEPT SLIGHTLY WARMER ON THE AREA
LAKES. WATER TEMPERATURES AT LAKE MURRAY IN THE LOW/MID 70S.
&&
.SHORT TERM /7 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
UPPER-LEVEL RIDGE AXIS OVER THE REGION WILL BEGIN BREAKING DOWN
MONDAY AFTERNOON IN ADVANCE OF A FRONTAL BOUNDARY CROSSING THE TN
VALLEY AND WESTERN GULF STATES. THIS WILL ALLOW ADDITIONAL
MOISTURE INTO THE FORECAST AREA WITH PWAT VALUES MONDAY AFTERNOON
AROUND 1.75 INCHES WITH MODERATE INSTABILITY. ALTHOUGH A STRONG
TRIGGER WILL NOT BE IN PLACE CONVECTION WHICH DEVELOPS COULD TAP
INTO SOME REMAINING MID-LEVEL DRY AIR RESULTING IN GUSTY OUTFLOWS
AND GENESIS OF NEW CELLS. CONTINUE TO EXPECT CHANCE SHOWERS AND
THUNDERSTORMS FOR MOST AREAS WITH LOW POTENTIAL FOR DAMAGING WINDS
GUSTS. CONVECTION WILL DIMINISH WITH SUNSET WITH CLOUDS LINGERING
MONDAY NIGHT AS THE BOUNDARY PUSHES INTO EASTERN TN AND THE
CENTRAL GULF STATES BY DAYBREAK TUESDAY. MODELS HAVE DECREASED
MOISTURE SLIGHTLY WITH THE LATEST RUN WITH PWAT VALUES AROUND
1.5 INCHES. FRONTAL BOUNDARY WILL CROSS THE AREA LATE TUESDAY
AFTERNOON/TUESDAY EVENING AND...ALTHOUGH WEAK...WILL BE ENOUGH TO
COMBINE WITH DIURNAL HEATING TO IGNITE ANOTHER ROUND OF SHOWERS
AND THUNDERSTORMS. SEVERE THREAT TUESDAY WILL REMAIN LOW.
TEMPERATURES WILL BE IN THE UPPER 80S TO LOWER 90S FOR DAYTIME
HIGHS WITH OVERNIGHT LOWS IN THE MID 60S TO NEAR 70.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
MODELS REMAIN IN GOOD AGREEMENT THROUGH THE LONG TERM WITH WEAK
HIGH PRESSURE NORTH OF THE AREA WEDNESDAY AND THE NEXT COLD FRONT
CROSSING THE REGION THURSDAY. WITH LOW-LEVEL MOISTURE REMAINING
IN PLACE AND THE FRONTAL BOUNDARY THROUGH THE REGION THE CHANCE OF
MAINLY DIURNAL SHOWERS AND THUNDERSTORMS WILL CONTINUE THURSDAY
THROUGH SUNDAY. TEMPERATURES THROUGH THE LONG TERM WILL BE
SLIGHTLY ABOVE NORMAL.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
EXPECT MAINLY VFR CONDITIONS THROUGH THE TAF PERIOD. LOW-LEVEL
MOISTURE UNDER THE NOCTURNAL INVERSION MAY HELP SUPPORT STRATUS
AND FOG DURING THE EARLY MORNING HOURS. HOWEVER...MOISTURE APPEARS
LIMITED AND THE NAM INDICATES SOME MIXING SHOULD OCCUR ASSOCIATED
WITH A LOW-LEVEL JET. MOST OF THE GFS AND NAM MOS MAINTAIN VFR
CONDITIONS. THE SREF GUIDANCE RESTRICTION PROBABILITIES ARE LOW.
THE HRRR INDICATES CONTINUED VFR CONDITIONS. FORECASTED VFR
CONDITIONS EXCEPT FOR A PERIOD OF MVFR FOG AT AGS AND OGB AROUND
SUNRISE BASED ON THE ADDED MOISTURE AND COOLING ASSOCIATED WITH
THE RIVER VALLEYS. HEATING AND MIXING SHOULD DISSIPATE ANY FOG
LATER IN THE MORNING. HEATING...A PRE-FRONTAL TROUGH AND A MID-
LEVEL SHORTWAVE TROUGH MOVING INTO THE RIDGE SHOULD HELP SUPPORT
THUNDERSTORMS MONDAY AFTERNOON. EXPECT SCATTERED COVERAGE WITH THE
THUNDERSTORM CHANCE TOO LOW TO INCLUDE IN THE TERMINAL FORECASTS
AT THIS TIME.
EXTENDED AVIATION OUTLOOK...RESTRICTIONS POSSIBLE IN MAINLY
AFTERNOON AND EVENING SCATTERED THUNDERSTORMS.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
99
AREA FORECAST DISCUSSION
NWS LINCOLN IL
900 PM CDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 852 PM CDT SUN MAY 17 2015
OVERNIGHT FORECAST DOING WELL. SOUTHERLY WINDS MAINTAINING SOME
WARM TEMPS FOR THE OVERNIGHT...AND MAJORITY OF PRECIP THREAT ALONG
AND SOUTH OF A LINE FROM TAYLORVILLE TO CHAMPAIGN. SHORT TERM
MODELS PREV BLEW SOME CONVECTION INTO SOUTHEASTERN IL WORKING OFF
OF OUTFLOW FROM ACTIVITY IN MO. HOWEVER, ATMOSPHERE HAVING
DIFFICULT TIME FOCUSING ANY LIFT, PARTICULARLY WITH THE LOSS OF
THE DIURNAL COMPONENT TO THE INSTABILITY. SHOWERS SO FAR HAVE
REMAINED LIMITED AND THE BULK OF THE THUNDER FURTHER TO THE SOUTH.
ISO TS POSSIBLE IN THE FAR SE...BUT NOT WIDESPREAD. NOT MUCH IN
THE WAY OF UPDATES ANTICIPATED AT THIS TIME.
&&
.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT SUN MAY 17 2015
POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON/EVENING IS STILL BEING
MONITORED...HOWEVER IT IS BEGINNING TO LOOK LIKE ANY SEVERE WILL BE
ISOLATED AT BEST. 18Z KILX UPPER AIR SOUNDING SHOWS SBCAPE OF
2000J/KG AND 0-6KM BULK SHEAR OF 35KT: HOWEVER, A WARM LAYER AT
AROUND 900MB IS KEEPING THE ATMOSPHERE MOSTLY CAPPED. REGIONAL
MESOSCALE ANALYSIS INDICATES A POCKET OF GREATER INSTABILITY ACROSS
NORTH-CENTRAL ILLINOIS FROM PEORIA/BLOOMINGTON NORTHWARD...MAKING
THIS THE PRIMARY SPOT FOR POTENTIAL CONVECTIVE DEVELOPMENT OVER THE
NEXT COUPLE OF HOURS. HRRR SHOWS THIS SCENARIO UNFOLDING...WITH
SCATTERED STORMS LIFTING NORTHWARD INTO NORTHERN ILLINOIS/SOUTHERN
WISCONSIN LATER THIS AFTERNOON. FURTHER SOUTH...THE UPSTREAM
AIRMASS ACROSS MISSOURI/SOUTHWEST ILLINOIS REMAINS STABLE AND CAPPED
IN THE WAKE OF A MORNING OUTFLOW BOUNDARY THAT HAS PUSHED WELL TO
THE EAST INTO WESTERN SECTIONS OF KENTUCKY AND TENNESSEE. END
RESULT WILL LIKELY BE ONLY WIDELY SCATTERED STORMS DEVELOPING ALONG
THE I-55 CORRIDOR AFTER 21Z...WITH MINIMAL SEVERE WEATHER THREAT.
HIGH-RES MODELS CONTINUE TO SUGGEST CONVECTION WILL RE-DEVELOP OVER
SOUTHEAST MISSOURI/ARKANSAS THIS EVENING...THEN LIFT INTO SOUTHEAST
ILLINOIS TONIGHT. PARTIAL CLEARING HAS OCCURRED ACROSS THIS
AREA...HOWEVER AIRMASS REMAINS STABLE BEHIND THE PREVIOUS OUTFLOW
BOUNDARY...SO AM SKEPTICAL OF THIS SOLUTION. WILL CONTINUE TO
MONITOR SOUTHEAST MISSOURI FOR DEVELOPMENT OVER THE NEXT SEVERAL
HOURS. AT THIS TIME...WILL CARRY ONLY SLIGHT OR LOW CHANCE POPS
WEST OF THE I-57 CORRIDOR THROUGH THE EVENING HOURS...WITH DRY
CONDITIONS OVERNIGHT. FURTHER EAST...WILL GO WITH HIGHER POPS IN
THE HIGHER DEWPOINT/MORE UNSTABLE AIRMASS ALONG/EAST OF I-57.
.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 256 PM CDT SUN MAY 17 2015
COLD FRONT WILL PASS THROUGH CENTRAL ILLINOIS ON MONDAY...DROPPING
SOUTH OF THE I-70 CORRIDOR BY LATE AFTERNOON. SCATTERED SHOWERS AND
THUNDERSTORMS MAY DEVELOP AHEAD OF THE FRONT...HOWEVER AREAL
COVERAGE WILL BE GREATEST FURTHER EAST ACROSS THE OHIO RIVER VALLEY.
WILL MAINTAIN CHANCE POPS ALONG/EAST OF A DANVILLE TO SHELBYVILLE
LINE THROUGHOUT THE DAY UNTIL THE BOUNDARY EXITS. HIGH PRESSURE
WILL TAKE CONTROL OF THE WEATHER BEHIND THE DEPARTING
FRONT...PROVIDING COOL/DRY WEATHER FOR TUESDAY. RESULTING HIGH
TEMPERATURES WILL REMAIN IN THE LOWER TO MIDDLE 60S...WHILE
OVERNIGHT LOWS DIP INTO THE 40S.
PIECE OF ENERGY IS EXPECTED TO EJECT FROM WESTERN CONUS UPPER LOW BY
MID-WEEK...BRINGING CLOUDS AND PERHAPS A FEW SHOWERS INTO THE AREA
ON WEDNESDAY. MODELS DEPICT A WEAKENING WAVE COMING INTO A VERY DRY
AIRMASS...SO THINK ANY RAINFALL WILL BE QUITE LIGHT. HAVE CUT BACK
ON POPS...FEATURING LIKELY ACROSS THE FAR SOUTHWEST CWA AROUND
JACKSONVILLE TAPERING DOWN TO JUST SLIGHT ALONG THE INDIANA BORDER.
ONCE THIS WAVE DEPARTS...COOL/DRY WEATHER WILL RETURN FOR THURSDAY
AND FRIDAY.
MAIN UPPER LOW WILL GRADUALLY LIFT INTO THE PLAINS LATE IN THE
PERIOD...BRINGING THE NEXT SIGNIFICANT CHANCE FOR RAIN BY LATE IN
THE WEEKEND. WHILE MODEL DIFFERENCES STILL EXIST...GFS/ECMWF
CONSENSUS POINTS TO THE SUNDAY/MONDAY TIME FRAME AS THE PRIMARY TIME
FOR SHOWERS AND THUNDERSTORMS. HAVE THEREFORE KEPT RAIN CHANCES OUT
OF THE FORECAST FOR SATURDAY...THEN HAVE HIT POPS HARD FOR SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 636 PM CDT SUN MAY 17 2015
MODELS INCONSISTENT AND NOT DOING WELL WITH TIMING OR DEVELOPMENT
OF CONVECTION AND CONSIDERING THE LACK OF ACTIVITY OUT TO THE WEST
THIS AFTERNOON...KEEPING EVEN MENTION OUT. MAY NEED TO CONSIDER
ADDING VCTS TO DEC OR CMI IN THE OVERNIGHT DEPENDING ON TRACK OF
WEAK CONVECTION TO THE SOUTHWEST...BUT SO FAR...NOT A MAJOR
THREAT. GUSTS EXPECTED TO SLACK OFF AS SUN SETS...WINDS BECOMING
MORE WESTERLY BY TOMORROW AND SOME SCT CU ALONG AND SOUTHEAST OR A
BMI TO SPI LINE FOR THE MOST PART, WITH SOME CIRRUS. SO FAR, A VFR
FORECAST THROUGH 24 HRS.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS LINCOLN IL
639 PM CDT SUN MAY 17 2015
.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT SUN MAY 17 2015
POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON/EVENING IS STILL BEING
MONITORED...HOWEVER IT IS BEGINNING TO LOOK LIKE ANY SEVERE WILL BE
ISOLATED AT BEST. 18Z KILX UPPER AIR SOUNDING SHOWS SBCAPE OF
2000J/KG AND 0-6KM BULK SHEAR OF 35KT: HOWEVER, A WARM LAYER AT
AROUND 900MB IS KEEPING THE ATMOSPHERE MOSTLY CAPPED. REGIONAL
MESOSCALE ANALYSIS INDICATES A POCKET OF GREATER INSTABILITY ACROSS
NORTH-CENTRAL ILLINOIS FROM PEORIA/BLOOMINGTON NORTHWARD...MAKING
THIS THE PRIMARY SPOT FOR POTENTIAL CONVECTIVE DEVELOPMENT OVER THE
NEXT COUPLE OF HOURS. HRRR SHOWS THIS SCENARIO UNFOLDING...WITH
SCATTERED STORMS LIFTING NORTHWARD INTO NORTHERN ILLINOIS/SOUTHERN
WISCONSIN LATER THIS AFTERNOON. FURTHER SOUTH...THE UPSTREAM
AIRMASS ACROSS MISSOURI/SOUTHWEST ILLINOIS REMAINS STABLE AND CAPPED
IN THE WAKE OF A MORNING OUTFLOW BOUNDARY THAT HAS PUSHED WELL TO
THE EAST INTO WESTERN SECTIONS OF KENTUCKY AND TENNESSEE. END
RESULT WILL LIKELY BE ONLY WIDELY SCATTERED STORMS DEVELOPING ALONG
THE I-55 CORRIDOR AFTER 21Z...WITH MINIMAL SEVERE WEATHER THREAT.
HIGH-RES MODELS CONTINUE TO SUGGEST CONVECTION WILL RE-DEVELOP OVER
SOUTHEAST MISSOURI/ARKANSAS THIS EVENING...THEN LIFT INTO SOUTHEAST
ILLINOIS TONIGHT. PARTIAL CLEARING HAS OCCURRED ACROSS THIS
AREA...HOWEVER AIRMASS REMAINS STABLE BEHIND THE PREVIOUS OUTFLOW
BOUNDARY...SO AM SKEPTICAL OF THIS SOLUTION. WILL CONTINUE TO
MONITOR SOUTHEAST MISSOURI FOR DEVELOPMENT OVER THE NEXT SEVERAL
HOURS. AT THIS TIME...WILL CARRY ONLY SLIGHT OR LOW CHANCE POPS
WEST OF THE I-57 CORRIDOR THROUGH THE EVENING HOURS...WITH DRY
CONDITIONS OVERNIGHT. FURTHER EAST...WILL GO WITH HIGHER POPS IN
THE HIGHER DEWPOINT/MORE UNSTABLE AIRMASS ALONG/EAST OF I-57.
.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 256 PM CDT SUN MAY 17 2015
COLD FRONT WILL PASS THROUGH CENTRAL ILLINOIS ON MONDAY...DROPPING
SOUTH OF THE I-70 CORRIDOR BY LATE AFTERNOON. SCATTERED SHOWERS AND
THUNDERSTORMS MAY DEVELOP AHEAD OF THE FRONT...HOWEVER AREAL
COVERAGE WILL BE GREATEST FURTHER EAST ACROSS THE OHIO RIVER VALLEY.
WILL MAINTAIN CHANCE POPS ALONG/EAST OF A DANVILLE TO SHELBYVILLE
LINE THROUGHOUT THE DAY UNTIL THE BOUNDARY EXITS. HIGH PRESSURE
WILL TAKE CONTROL OF THE WEATHER BEHIND THE DEPARTING
FRONT...PROVIDING COOL/DRY WEATHER FOR TUESDAY. RESULTING HIGH
TEMPERATURES WILL REMAIN IN THE LOWER TO MIDDLE 60S...WHILE
OVERNIGHT LOWS DIP INTO THE 40S.
PIECE OF ENERGY IS EXPECTED TO EJECT FROM WESTERN CONUS UPPER LOW BY
MID-WEEK...BRINGING CLOUDS AND PERHAPS A FEW SHOWERS INTO THE AREA
ON WEDNESDAY. MODELS DEPICT A WEAKENING WAVE COMING INTO A VERY DRY
AIRMASS...SO THINK ANY RAINFALL WILL BE QUITE LIGHT. HAVE CUT BACK
ON POPS...FEATURING LIKELY ACROSS THE FAR SOUTHWEST CWA AROUND
JACKSONVILLE TAPERING DOWN TO JUST SLIGHT ALONG THE INDIANA BORDER.
ONCE THIS WAVE DEPARTS...COOL/DRY WEATHER WILL RETURN FOR THURSDAY
AND FRIDAY.
MAIN UPPER LOW WILL GRADUALLY LIFT INTO THE PLAINS LATE IN THE
PERIOD...BRINGING THE NEXT SIGNIFICANT CHANCE FOR RAIN BY LATE IN
THE WEEKEND. WHILE MODEL DIFFERENCES STILL EXIST...GFS/ECMWF
CONSENSUS POINTS TO THE SUNDAY/MONDAY TIME FRAME AS THE PRIMARY TIME
FOR SHOWERS AND THUNDERSTORMS. HAVE THEREFORE KEPT RAIN CHANCES OUT
OF THE FORECAST FOR SATURDAY...THEN HAVE HIT POPS HARD FOR SUNDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 636 PM CDT SUN MAY 17 2015
MODELS INCONSISTENT AND NOT DOING WELL WITH TIMING OR DEVELOPMENT
OF CONVECTION AND CONSIDERING THE LACK OF ACTIVITY OUT TO THE WEST
THIS AFTERNOON...KEEPING EVEN MENTION OUT. MAY NEED TO CONSIDER
ADDING VCTS TO DEC OR CMI IN THE OVERNIGHT DEPENDING ON TRACK OF
WEAK CONVECTION TO THE SOUTHWEST...BUT SO FAR...NOT A MAJOR
THREAT. GUSTS EXPECTED TO SLACK OFF AS SUN SETS...WINDS BECOMING
MORE WESTERLY BY TOMORROW AND SOME SCT CU ALONG AND SOUTHEAST OR A
BMI TO SPI LINE FOR THE MOST PART, WITH SOME CIRRUS. SO FAR, A VFR
FORECAST THROUGH 24 HRS.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1234 PM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 947 AM CDT SAT MAY 16 2015
SHOWERS INCREASING IN COVERAGE TO OUR SOUTH...AND HAVE SEEN
SCATTERED SHOWERS ALSO DEVELOPING MORE WITHIN OUR FORECAST AREA.
SO FAR THUNDER UPSTREAM HAS BEEN RATHER MINIMAL...AND SURFACE
BASED CAPE VALUES PROGGED BY THE RAP MODEL EXPECTED TO BE LESS
THAN 500 J/KG FROM ABOUT I-57 EASTWARD. WITH NO SUBSTANTIAL
HEATING IN THAT AREA...HAVE DOWNPLAYED THE THUNDER POTENTIAL
ACROSS THE EASTERN CWA THROUGH THE AFTERNOON. FURTHER WEST...
CAPES 1000-1500 J/KG EXPECTED AND THERE ARE ALSO SOME SUBSTANTIAL
BREAKS IN THE CLOUDS ACROSS SOUTHERN IOWA AND NORTHEAST
MISSOURI...SO HAVE MAINTAINED GENERAL SHOWER/THUNDERSTORM MENTION
ACROSS THE REMAINDER OF THE FORECAST AREA. WITH RAIN ACROSS THE
SOUTHEAST CWA EXPECTED TO BECOME FAIRLY WIDESPREAD...HAVE LOWERED
HIGHS IN THAT AREA A COUPLE DEGREES...WITH MOST OF THE REMAINING
CWA GENERALLY EXPECTED TO REACH AROUND 80 DEGREES.
&&
.SHORT TERM...(TODAY)
ISSUED AT 336 AM CDT SAT MAY 16 2015
ANOTHER RELATIVELY WARM AND HUMID DAY IS ANTICIPATED ACROSS CENTRAL
AND SOUTHEAST ILLINOIS TODAY AS SOUTHERLY LOW LEVEL FLOW PERSISTS.
DAYTIME HIGHS MAY BE A FEW DEGREES COOLER THAN YESTERDAY, ESPECIALLY
ACROSS SOUTHEAST ILLINOIS WHERE CLOUD COVER WILL BE THICKEST AND
RAINFALL MOST WIDESPREAD, BUT MOST LOCATIONS SHOULD STILL CRACK THE
80 DEGREE MARK.
AS FAR AS SHOWER/STORM POTENTIAL TODAY, GIVEN THE FAIRLY JUICED UP
LOW-LEVEL AIRMASS AND LACK OF APPRECIABLE CAPPING, IT WILL NOT TAKE
MUCH TO POP OFF SOME CONVECTION. PLAN TO CARRY AT LEAST CHANCE POPS
AREAWIDE TODAY GIVEN THIS POTENTIAL. MODEL PROGS SUGGEST MOST OF THE
FORECAST AREA SHOULD SEE DIURNALLY INDUCED CAPE VALUES OF AT 1500
J/KG, ALTHOUGH SHEAR PROFILES SHOULD BE QUITE WEAK OVER THE NORTHERN
2/3 OR SO OF THE REGION. THE BETTER FORCING ACROSS SOUTHEAST
ILLINOIS WILL COME COURTESY OF A WEAK SHORT WAVE LIFTING NORTHEAST
FROM THE MID-MISSISSIPPI RIVER VALLEY. HAVE BUMPED POPS UP TO
CATEGORICAL SOUTH OF I-70 FOR THE MIDDAY/EARLY AFTERNOON HOURS TO
ACCOUNT FOR THE PASSAGE OF THIS WAVE.
.LONG TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 336 AM CDT SAT MAY 16 2015
DIURNALLY ENHNANCED CONVECTION THIS AFTERNOON AND EARLY EVENING WILL
DIMINISH IN COVERAGE AFTER SUNSET SIMILAR TO WHAT HAPPENED FRIDAY
EVENING AS INSTABILITY WANES. WILL CARRY HIGHEST POPS IN
SOUTHEAST IL THIS EVENING ESPECIALLY BEFORE DARK WITH SHORT WAVES
NEAR EASTERN/SE IL EARLY THIS EVENING AROUND 00Z/7 PM. MILD LOWS
TONIGHT IN THE MID TO UPPER 60S WITH MILDEST READINGS SW AREAS.
CUTOFF LOW OVER THE CENTRAL ROCKIES TO EJECT NE INTO MN BY SUNDAY
EVENING AND HAS A PREFRONTAL TROF PUSHING EAST TOWARD THE MS RIVER.
THIS TO INCREASE CHANCES OF CONVECTION FROM WEST TO EAST DURING THE
DAY SUNDAY AND THEN DIMINISH FROM WEST TO EAST DURING SUNDAY NIGHT.
SPC HAS SLIGHT RISK OF SEVERE STORMS SUNDAY AFTERNOON/EVENING FROM
BLOOMINGTON TO TAYLORVILLE WEST WHERE STRONGER BULK SHEAR OF 35-45
KTS OCCURS ALONG WITH INCREASE INSTABILITY WITH CAPES PEAKING AROUND
2500 J/KG SUNDAY AFTERNOON. WARM HIGHS IN THE LOWER 80S SUNDAY WITH
BREEZY SSW WINDS AND MUGGY DEWPOINTS IN THE MID TO UPPER 60S.
MAIN COLD FRONT TO PUSH EAST ACROSS IL DURING MONDAY AND BRINGS BEST
CHANCES OF SHOWERS AND THUNDERSTORMS TO AREAS EAST OF I-55. SPC
KEEPS MARGINAL RISK OF SEVERE EAST OF IL OVER PARTS OF INDIANA ON
MONDAY. HAVE BUMPED UP THE HIGHS ON MONDAY A FEW DEGREES WITH MID
70S FROM IL RIVER NW TO LOWER 80S IN EASTERN IL.
DRIER...COOLER AND LESS HUMID AIR USHERS INTO IL DURING MONDAY NIGHT
AND TUE BEHIND THE COLD FRONT. LOWS MONDAY NIGHT RANGE FROM MID 40S
NW OF IL RIVER TO NEAR 55F FAR SE IL NEAR WABASH RIVER BY
LAWRENCVILLE. HIGHS TUE IN THE MID 60S CENTRAL IL AND 65-70F IN
SOUTHEAST IL. A COOL NIGHT AHEAD FOR TUE NIGHT WITH LOWS IN THE MID
TO UPPER 40S.
EXTENDED MODELS TRY TO BRING SOME QPF BACK INTO PARTS OF CENTRAL AND
ESPECIALLY SOUTHERN/SW IL WED AND THEN SUPPRESS IS SOUTHWARD BY THU
WITH SOME ENERGY EJECTING FROM THE UPPER LEVEL TROF/LOW NEAR CA AND
MOVING INTO THE MID/LOWER MS RIVER VALLEY. WILL KEEP POPS LOW FROM
WED-THU WITH MAINLY SLIGHT CHANCES, THOUGH SW AREAS HAVE CHANCE POPS
30-40% WED AND WED EVENING. HIGHS IN THE LOW TO MID 60S WED AND 65
TO 70F ON THU. TEMPS CONTINUE TO SLOWLY MODIFY FRIDAY WITH HIGHS
MAINLY IN THE LOWER 70S AND DRY CONDITIONS WITH WEAK HIGH PRESSURE
IN THE CENTRAL PLAINS AND RIDGING EAST TOWARD IL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1234 PM CDT SAT MAY 16 2015
SOME MVFR CEILINGS LINGER AROUND KBMI/KCMI AT MIDDAY...BUT THESE
SHOULD CONTINUE TO IMPROVE. ASIDE FROM A CLUSTER OF STORMS THAT
HAVE RECENTLY PASSED KBMI...CONVECTION REMAINS RATHER ISOLATED AND
DISORGANIZED. THE CURRENT STATE OF THE ATMOSPHERE DOES NOT HAVE
ANY PARTICULAR BOUNDARIES OR FRONTS TO FOCUS THE ACTION...THUS
WILL MAINTAIN THE VCTS MENTIONS FOR NOW...AND WILL UPDATE WHEN
THE CONVECTION STARTS TO GET ORGANIZED. MOST OF THE HIGH-
RESOLUTION MODEL GUIDANCE LARGELY HAS THE THREAT OUT OF CENTRAL
ILLINOIS BY 00Z AND HAVE KEPT THE OVERNIGHT HOURS DRY. SOME
QUESTION AS TO HOW LOW THE CEILINGS WILL GET AND WILL GO WITH
LOW-END MVFR CEILINGS AT ALL SITES. LOW-LEVEL WIND SHEAR IS
MARGINAL FOR TONIGHT...BUT WILL HAVE TO MONITOR THIS POTENTIAL
OVER THE NEXT FEW HOURS. SOME OF THIS LOW LEVEL JET WILL WORK
TOWARD THE SURFACE SUNDAY MORNING...AND SOUTHERLY GUSTS SHOULD
START REACHING 20 KNOTS OR SO BY MID MORNING.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...BAK
LONG TERM...07
AVIATION...GEELHART
AREA FORECAST DISCUSSION
NWS LINCOLN IL
948 AM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 947 AM CDT SAT MAY 16 2015
SHOWERS INCREASING IN COVERAGE TO OUR SOUTH...AND HAVE SEEN
SCATTERED SHOWERS ALSO DEVELOPING MORE WITHIN OUR FORECAST AREA.
SO FAR THUNDER UPSTREAM HAS BEEN RATHER MINIMAL...AND SURFACE
BASED CAPE VALUES PROGGED BY THE RAP MODEL EXPECTED TO BE LESS
THAN 500 J/KG FROM ABOUT I-57 EASTWARD. WITH NO SUBSTANTIAL
HEATING IN THAT AREA...HAVE DOWNPLAYED THE THUNDER POTENTIAL
ACROSS THE EASTERN CWA THROUGH THE AFTERNOON. FURTHER WEST...
CAPES 1000-1500 J/KG EXPECTED AND THERE ARE ALSO SOME SUBSTANTIAL
BREAKS IN THE CLOUDS ACROSS SOUTHERN IOWA AND NORTHEAST
MISSOURI...SO HAVE MAINTAINED GENERAL SHOWER/THUNDERSTORM MENTION
ACROSS THE REMAINDER OF THE FORECAST AREA. WITH RAIN ACROSS THE
SOUTHEAST CWA EXPECTED TO BECOME FAIRLY WIDESPREAD...HAVE LOWERED
HIGHS IN THAT AREA A COUPLE DEGREES...WITH MOST OF THE REMAINING
CWA GENERALLY EXPECTED TO REACH AROUND 80 DEGREES.
&&
.SHORT TERM...(TODAY)
ISSUED AT 336 AM CDT SAT MAY 16 2015
ANOTHER RELATIVELY WARM AND HUMID DAY IS ANTICIPATED ACROSS CENTRAL
AND SOUTHEAST ILLINOIS TODAY AS SOUTHERLY LOW LEVEL FLOW PERSISTS.
DAYTIME HIGHS MAY BE A FEW DEGREES COOLER THAN YESTERDAY, ESPECIALLY
ACROSS SOUTHEAST ILLINOIS WHERE CLOUD COVER WILL BE THICKEST AND
RAINFALL MOST WIDESPREAD, BUT MOST LOCATIONS SHOULD STILL CRACK THE
80 DEGREE MARK.
AS FAR AS SHOWER/STORM POTENTIAL TODAY, GIVEN THE FAIRLY JUICED UP
LOW-LEVEL AIRMASS AND LACK OF APPRECIABLE CAPPING, IT WILL NOT TAKE
MUCH TO POP OFF SOME CONVECTION. PLAN TO CARRY AT LEAST CHANCE POPS
AREAWIDE TODAY GIVEN THIS POTENTIAL. MODEL PROGS SUGGEST MOST OF THE
FORECAST AREA SHOULD SEE DIURNALLY INDUCED CAPE VALUES OF AT 1500
J/KG, ALTHOUGH SHEAR PROFILES SHOULD BE QUITE WEAK OVER THE NORTHERN
2/3 OR SO OF THE REGION. THE BETTER FORCING ACROSS SOUTHEAST
ILLINOIS WILL COME COURTESY OF A WEAK SHORT WAVE LIFTING NORTHEAST
FROM THE MID-MISSISSIPPI RIVER VALLEY. HAVE BUMPED POPS UP TO
CATEGORICAL SOUTH OF I-70 FOR THE MIDDAY/EARLY AFTERNOON HOURS TO
ACCOUNT FOR THE PASSAGE OF THIS WAVE.
.LONG TERM...(TONIGHT THROUGH FRIDAY)
ISSUED AT 336 AM CDT SAT MAY 16 2015
DIURNALLY ENHNANCED CONVECTION THIS AFTERNOON AND EARLY EVENING WILL
DIMINISH IN COVERAGE AFTER SUNSET SIMILAR TO WHAT HAPPENED FRIDAY
EVENING AS INSTABILITY WANES. WILL CARRY HIGHEST POPS IN
SOUTHEAST IL THIS EVENING ESPECIALLY BEFORE DARK WITH SHORT WAVES
NEAR EASTERN/SE IL EARLY THIS EVENING AROUND 00Z/7 PM. MILD LOWS
TONIGHT IN THE MID TO UPPER 60S WITH MILDEST READINGS SW AREAS.
CUTOFF LOW OVER THE CENTRAL ROCKIES TO EJECT NE INTO MN BY SUNDAY
EVENING AND HAS A PREFRONTAL TROF PUSHING EAST TOWARD THE MS RIVER.
THIS TO INCREASE CHANCES OF CONVECTION FROM WEST TO EAST DURING THE
DAY SUNDAY AND THEN DIMINISH FROM WEST TO EAST DURING SUNDAY NIGHT.
SPC HAS SLIGHT RISK OF SEVERE STORMS SUNDAY AFTERNOON/EVENING FROM
BLOOMINGTON TO TAYLORVILLE WEST WHERE STRONGER BULK SHEAR OF 35-45
KTS OCCURS ALONG WITH INCREASE INSTABILITY WITH CAPES PEAKING AROUND
2500 J/KG SUNDAY AFTERNOON. WARM HIGHS IN THE LOWER 80S SUNDAY WITH
BREEZY SSW WINDS AND MUGGY DEWPOINTS IN THE MID TO UPPER 60S.
MAIN COLD FRONT TO PUSH EAST ACROSS IL DURING MONDAY AND BRINGS BEST
CHANCES OF SHOWERS AND THUNDERSTORMS TO AREAS EAST OF I-55. SPC
KEEPS MARGINAL RISK OF SEVERE EAST OF IL OVER PARTS OF INDIANA ON
MONDAY. HAVE BUMPED UP THE HIGHS ON MONDAY A FEW DEGREES WITH MID
70S FROM IL RIVER NW TO LOWER 80S IN EASTERN IL.
DRIER...COOLER AND LESS HUMID AIR USHERS INTO IL DURING MONDAY NIGHT
AND TUE BEHIND THE COLD FRONT. LOWS MONDAY NIGHT RANGE FROM MID 40S
NW OF IL RIVER TO NEAR 55F FAR SE IL NEAR WABASH RIVER BY
LAWRENCVILLE. HIGHS TUE IN THE MID 60S CENTRAL IL AND 65-70F IN
SOUTHEAST IL. A COOL NIGHT AHEAD FOR TUE NIGHT WITH LOWS IN THE MID
TO UPPER 40S.
EXTENDED MODELS TRY TO BRING SOME QPF BACK INTO PARTS OF CENTRAL AND
ESPECIALLY SOUTHERN/SW IL WED AND THEN SUPPRESS IS SOUTHWARD BY THU
WITH SOME ENERGY EJECTING FROM THE UPPER LEVEL TROF/LOW NEAR CA AND
MOVING INTO THE MID/LOWER MS RIVER VALLEY. WILL KEEP POPS LOW FROM
WED-THU WITH MAINLY SLIGHT CHANCES, THOUGH SW AREAS HAVE CHANCE POPS
30-40% WED AND WED EVENING. HIGHS IN THE LOW TO MID 60S WED AND 65
TO 70F ON THU. TEMPS CONTINUE TO SLOWLY MODIFY FRIDAY WITH HIGHS
MAINLY IN THE LOWER 70S AND DRY CONDITIONS WITH WEAK HIGH PRESSURE
IN THE CENTRAL PLAINS AND RIDGING EAST TOWARD IL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 639 AM CDT SAT MAY 16 2015
AREAS OF IFR STRATUS AND FOG HAVE DEVELOPED ACROSS CENTRAL
ILLINOIS EARLY THIS MORNING. THIS STRATUS/FOG SHOULD BURN OFF
WITHIN THE NEXT FEW HOURS AS DIURNAL HEATING INCREASES. THEN,
ATTENTION TURNS TO AN UPPER LEVEL DISTURBANCE LIFTING NORTHEAST
INTO THE AREA. THIS DISTURBANCE SHOULD PRODUCE AT LEAST SCATTERED
SHOWERS/STORMS TODAY AS IT MOVES THROUGH, WITH KDEC & KCMI THE
MOST LIKELY OF THE LOCAL TERMINALS TO BE IMPACTED. HAVE INCLUDED A
4 HOUR TEMPO FOR THUNDER AT THOSE LOCATIONS DURING THE PREFERRED
TIME PERIOD, BUT ONLY INCLUDED A VCTS AT KPIA, KBMI, AND KSPI AS
THE STORM COVERAGE SHOULD BE MORE SPOTTY FURTHER WEST. CAN`T RULE
OUT SOME CONVECTION POPPING UP OUTSIDE THE FAVORED DIURNAL HEATING
PERIOD, WHICH OVERLAPS TODAY WITH THE PASSAGE OF THE DISTURBANCE,
BUT EXPECTED COVERAGE IS TOO LOW TO MENTION AT THIS TIME. AS THE
AIRMASS, CLOUD, AND WIND CONDITIONS SHOULD BE SIMILAR TONIGHT TO
EARLY THIS MORNING, PLAN TO HAVE IFR CONDITIONS DEVELOPING ONCE
AGAIN LATER TONIGHT.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEELHART
SHORT TERM...BAK
LONG TERM...07
AVIATION...BAK
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1152 PM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 906 PM CDT FRI MAY 15 2015
PLENTY OF WARM AIR ADVECTING INTO THE REGION AND WIDESPREAD
MID/HIGH LEVEL CLOUDS IN ADDITION TO REMAINING LOW WILL KEEP THE
TEMPS UP OVERNIGHT FOR CENTRAL ILLINOIS. ALTHOUGH LLVL RH HAS BEEN
ENHANCED BY THE EVENINGS RAINFALL...WIDESPREAD FOG NOT LIKELY AS
THE WINDS AND TEMPS STAY UP OVERNIGHT. WILL HAVE TO WATCH FOR SOME
PATCHY VIS REDUCTIONS, BUT NOT ENOUGH CONFIDENCE TO PUT IT IN THE
ZONES JUST YET. UPDATES FOR THE BREAK IN THE PRECIP...BRINGING
BACK CHANCE POPS IN THE VERY EARLY HOURS OF THE MORNING AS MODELS
STILL SPLIT OVER HOW TO HANDLE A POTENTIAL ROUND TWO.
&&
.SHORT TERM...(TONIGHT)
ISSUED AT 253 PM CDT FRI MAY 15 2015
THUNDERSTORMS HAVE BEEN ON THE INCREASE ACROSS MISSOURI THE LAST FEW
HOURS AS A SHORTWAVE LIFTS NORTHEAST...WITH MORE ISOLATED CONVECTION
IN THE SOUTHEASTERN CWA. NOT MUCH HOLDING THESE STORMS BACK AS
SURFACE BASED CAPE`S ARE OVER 2500 J/KG...BUT VERY LITTLE WIND SHEAR
ALOFT IS RESULTING IN A MORE PULSE-TYPE STORM ENVIRONMENT. HRRR
MODEL LIFTS THE BULK OF THESE STORMS THROUGH THE FORECAST AREA BY 8-
9 PM. MODEL GUIDANCE BEYOND THAT GETS A BIT MORE DISJOINTED...AS
SEVERAL OF THE HIGH-RESOLUTION MODELS PRETTY MUCH DRY THINGS OUT
ALTHOUGH THE HRRR TRIES TO BRING ANOTHER LOBE THROUGH LATE EVENING.
HAVE LARGELY GONE WITH 30-40% POP`S THROUGH THE NIGHT IN MOST AREAS
EXCEPT FOR SOME HIGHER VALUES EARLY EVENING ACROSS THE SOUTHWEST CWA
WITH THE CURRENT ACTIVITY. HOURLY TEMPERATURES WILL BE TRICKY AS THE
STORMS WILL CAUSE SOME TEMPORARY COOLDOWNS...BUT OVERALL LOWS IN THE
MID 60S REQUIRED LITTLE CHANGE FROM THE PREVIOUS FORECAST.
.LONG TERM...(SATURDAY THROUGH FRIDAY)
ISSUED AT 253 PM CDT FRI MAY 15 2015
MORNING UPPER AIR AND MOISTURE CHANNEL IMAGERY SHOWS CLOSED UPPER
LOW IN ROCKIES WITH A MAIN VORT LOBE IN THE CENTRAL PLAINS,
ADVECTING DEEP MOISTURE PLUME NORTHWARD FROM TX INTO THE CENTRAL
MIDWEST. SURFACE DATA SHOWS VERY MOIST AIRMASS OVER IL REGION,
WITH 2500 CAPE, DEW POINTS APPROACHING 70 AND TEMPS IN LOWER 80S.
WITH THE PROGGED CONTINUING OF THE MOISTURE FETCH NORTHWARD
TONIGHT THROUGH MUCH OF STATE SATURDAY, THERE WILL BE LITTLE
CHANGE IN RESULT FOR THE START OF WEEKEND.
EXPECT SCATTERED STORMS TONIGHT INTO DAY SATURDAY, BUT WILL LIMITED
SHEAR AVAILABLE, SEVERE POTENTIAL WILL BE ON THE LOCALIZED SCALE.
BY SUNDAY THOUGH, PATTERN CHANGES AS THE UPPER LOW STARTS TO MOVE
NORTHEAST SATURDAY NIGHT. BY SUNDAY IT REACHES THE DAKOTAS AND
ANOTHER WAVE ROTATES EAST AROUND THE LOW INTO THE PLAINS. THIS WILL
GET THE FRONT MOVING EAST, PROVIDING AN INCREASE IN SHEAR AND
CONVERGENCE INTO THE IL REGION ON SUNDAY. WITH LITTLE CHANGE IN
MOISTURE, THE AFTERNOON AND EVENING WILL BE THE BEST CHANCES FOR
ORGANIZED SEVERE. AMOUNT OF SHEAR AND STRENGTH OF UPPER LEVEL
SUPPORT IN THE AREA STILL A LITTLE UNCERTAIN, BUT A SLIGHT RISK OF
SEVERE STILL IS SUPPORTABLE.
DRYING SUNDAY NIGHT AS UPPER WAVE MOVES EAST WILL CLEAR PCPN CHANCES
FOR MONDAY. COOLER AIR MOVES IN AND WILL SOME WEAK RIDGING ALOFT,
QUITE WEATHER IS RULE EARLY IN THE WEEK. A WEAK UPPER LEVEL WAVE
MOVES OUT OF STILL STAGNATE UPPER TROUGH IN THE WESTERN ROCKIES,
WHICH WILL BRING CHANCE OF PCPN WED TO THURS, BUT WITH DRIER, MORE
STABLE AIR IN AREA, SLIGHT CHANCE POPS ARE THE RESULT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1149 PM CDT FRI MAY 15 2015
ILX TERMINALS STILL ANCHORED IN THE WARM SECTOR OF SORTS
TOMORROW...MAINTAINING THE TREND OF SOUTHERLY WINDS AND SHOWERS
AND THUNDERSTORMS WITH A DIURNAL COMPONENT THROUGH TOMORROW.
MODELS INCONSISTENT WITH TIMING OF THE ONSET OF SHOWERS...BUT WITH
THE RUNS THAT HAVE IT EARLIER...THEY ARE ALSO OVERDONE WITH THE
SECONDARY SHOWERS TO THE SOUTHWEST. AS A RESULT...KEEPING TO VCSH
UNTIL ROUGHLY MIDDAY. SPREAD OF PRECIP NOT A PROGRESSION BUT MORE
SCATTERED. PULLING BACK ON THE RAIN MENTION FOR THE EVENING WITH
THE MID DECK REESTABLISHING...VERY SIMILAR TO THIS EVENING.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...GEELHART
LONG TERM...GOETSCH
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
219 PM EDT SAT MAY 16 2015
.SYNOPSIS...
ISSUED AT 149 PM EDT SAT MAY 16 2015
THE COMBINATION OF A STALLED FRONT ACROSS THE REGION AND A SERIES
OF UPPER LEVEL DISTURBANCES TRACKING ACROSS THE AREA WILL RESULT
IN SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND TONIGHT.
SHOWERS AND THUNDERSTORMS WILL BECOME MORE LIKELY BY SUNDAY NIGHT
AS A STRONGER SYSTEM APPROACHES FROM THE WEST. OTHERWISE...WARM
CONDITIONS WILL CONTINUE THROUGH THE WEEKEND. HIGH TEMPERATURES
THIS AFTERNOON WILL REACH AROUND 75...WITH LOW TEMPERATURES
TONIGHT DROPPING INTO THE MIDDLE 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 402 AM EDT SAT MAY 16 2015
NORTHWARD SHIFT TO LOW/MID LEVEL THETAE GRADIENT WILL CONTINUE THIS
MORNING AS A SERIES OF SMALL SCALE SHORT WAVES LIFT INTO NORTHEAST
INDIANA. THE MOST PRONOUNCED OF THESE SMALL SCALE VORTICES APPEARS
TO BE TRACKING ACROSS CENTRAL INDIANA AT THIS TIME. THROUGH THE
EARLY MORNING HOURS HAVE INDICATED A SOUTH TO NORTH INCREASE IN POPS
FOLLOWING PROGRESSION OF SHORT WAVE FORCING/MOISTURE
ADVECTION...AND AN ISOLD THUNDER MENTION WITH STILL SOME 250-500
K/G MUCAPES ANALYZED PER LATEST RUC ANALYSIS FOR SLIGHTLY ELEVATED
PARCELS. COVERAGE OF SHOWERS AND ISOLATED THUNDER SHOULD GRADUALLY
WIND DOWN IN THE 12-14Z TIMEFRAME.
LOOKING UPSTREAM...ADDITIONAL WEAK SHORT WAVES WILL TEND TO SHEAR
WITH NORTHWARD EXTENT AS THEY ENTER THE LOCAL AREA FROM THE
LOWER/MID MS VALLEY THIS AFTERNOON. QUITE CHALLENGING TO CLEARLY
PICK OUT THESE UPSTREAM WAVES THIS MORNING...ALTHOUGH BULK OF
GUIDANCE WOULD SUGGEST SOUTH/SOUTHEAST LOCATIONS WITH MORE
FAVORABLE SHORT WAVE TRACK THROUGH THIS AFTERNOON. A MODEST
MID/UPPER LEVEL SPEED MAX IS ALSO EXPECTED TO LIFT ACROSS EAST
CENTRAL INDIANA/WESTERN OHIO THIS AFTERNOON WHICH MAY ALSO TEND TO
FOCUS BETTER CONVECTIVE CHANCES. HAVE CONTINUED WITH MID TO HIGH
CHANCE POPS THROUGH THE DAY WITH HIGHEST POPS FOCUSED ACROSS
SOUTHEAST THIRD OF THE AREA. INSTABILITY MAGNITUDES SHOULD BE
SOMEWHAT LESS THAN YESTERDAY AS LOW LEVEL THERMAL RIDGE IS
WEAKER...AND GENERALLY EXPECTING SURFACED BASED CAPES ON THE ORDER
OF 750-1500 J/KG THIS AFTERNOON. SHEAR ALSO IS EXPECTED TO BE ON THE
MARGINAL SIDE WITH THE POSSIBLE EXCEPTION OF FAR SOUTHEAST AREAS
WHERE AFOREMENTIONED MID/UPPER JET STREAK MAY PROMOTE DEEP LAYER
SHEAR VALUES APPROACHING THE 25-30 KNOT RANGE. THIS MAY HELP TO
CONCENTRATE SCATTERED CONVECTION WITH THE APPROACH OF THE NEXT
SHORT WAVE ACROSS THE SOUTHEAST THIRD...BUT SEVERE WEATHER IS NOT
EXPECTED. NO CHANGE TO PREVIOUS FORECAST WITH HIGHS AROUND 80 FOR
TODAY...ALTHOUGH IF GREATER CONVECTIVE COVERAGE IS ABLE TO BECOME
ESTABLISHED ACROSS THE SOUTH/SOUTHEAST...HIGHS MAY BE A BIT TOO
WARM.
FORECAST CONFIDENCE FOR TONIGHT IS RELATIVELY LOW GIVEN THE LOW
PREDICTABILITY WITH SMALLER SCALE WAVES IN SOUTHWEST FLOW...BUT
CURRENT INDICATIONS SUGGEST THE DEPARTING SHORT WAVE ACROSS
SOUTHEAST HALF OF THE AREA MAY PROVIDE BEST EVENING CHANCES ACROSS
THESE LOCATIONS. OTHERWISE...FORCING LOOKS QUITE MEAGER FOR MOST OF
THE NIGHT. MOIST AIR MASS/CLOUD COVER SHOULD KEEP TEMPS IN THE MID
60S FOR LOWS MOST LOCATIONS. SOME PATCHY FOG IS
POSSIBLE...PARTICULARLY ACROSS THE FAR NORTH IN CLOSER PROXIMITY TO
STALLED LOW LEVEL FRONT BUT WILL OMIT FROM FORECAST AT THIS TIME.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 402 AM EDT SAT MAY 16 2015
PRECIP CHANCES STEADILY INCREASE INTO LATE SUNDAY AS LARGE CUTOFF
LOW FINALLY BEGINS TO MAKE SOME EASTWARD PROGRESS. STILL A FAIR
AMOUNT OF UNCERTAINTY REGARDING EXACT TIMING AND EVOLUTION OF
NORTHEAST EJECTION THOUGH. MAIN VORTICITY LOBE WILL PASS WELL TO OUR
NORTHWEST WITH JUST A FEW TRAILING EMBEDDED SHORTWAVES TO SPARK
CONVECTION IN OUR CWA. LEANED TOWARD THE LATEST GFS SOLUTION WHICH
HAS SUPPORT FROM THE ECMWF...SEVERAL OF THE NEWEST HI-RES RUNS...AND
IS IN LINE WITH PREVIOUS FORECAST. EXPECT BEST CHANCES FOR RAIN
DURING THE LATE AFTERNOON AND EVENING WITH LITTLE PRECIP BEFORE 18Z.
AFOREMENTIONED MODELS SHOW DECENT SHORTWAVE/PREFRONTAL SURFACE
TROUGH LIFTING INTO THE GREAT LAKES AT THIS TIME...COMMENSURATE WITH
A NOTED SURGE IN LOW LEVEL THETA-E ON THE NOSE OF A 30-35 KT 850MB
JET. SHOULD ALSO BE ABLE TO CAPITALIZE ON SOME MODERATE
INSTABILITY...THOUGH IT WILL STEADILY WANE AFTER SUNSET.
STILL...WOULD LIKE TO SEE BETTER DEFINED SYNOPTIC FORCING AND MODEL
AGREEMENT BEFORE BOOSTING POP FORECAST AND WILL HOLD WITH LOW END
LIKELY FOR NOW. MIDLEVEL LAPSE RATES ARE A LITTLE BETTER (6-6.5
C/KM) BUT MLCAPE VALUES STILL STRUGGLE TO GET MUCH ABOVE 1000
J/KG...ESPECIALLY BY 00Z WHEN THE BETTER 0-6KM SHEAR SPREADS INTO
THE AREA. SEVERE RISK IS THEREFORE LOW...CONFINED MAINLY TO OUR
WESTERN HALF DURING THE EARLY EVENING PERIOD. STRONG WIND GUSTS AND
SMALL HAIL WOULD BE THE PRIMARY THREATS IF SEVERE WEATHER DOES OCCUR.
ACTUAL COLD FRONT WILL NOT CROSS THE AREA UNTIL MONDAY NIGHT SO
COULD STILL BE SOME RESIDUAL CONVECTION...ESPECIALLY OVER OUR
EASTERN COUNTIES...ON MONDAY. COVERAGE/CHANCES WILL DEPEND ON HOW
SUNDAY NIGHT`S PRECIP EVOLVES WITH A POSSIBILITY OUR AREA WILL BE
TOO "WORKED OVER" FOR WIDESPREAD PRECIP. LLJ WEAKENS AND VEERS BY
MONDAY MORNING WITH BEST MOISTURE CONVERGENCE SHUNTED TO OUR EAST.
SIMILARLY...INSTABILITY REMAINS ON THE MARGINAL SIDE AND SEVERE RISK
IS LOW. INHERITED CHANCE POPS SEEM APPROPRIATE...THOUGH WILL BUMP
THEM UP A BIT IN OUR FAR EASTERN COUNTIES WHERE SLIGHTLY BETTER
MOISTURE/INSTABILITY RESIDE. REST OF THE WEEK STILL LOOKING COOL AND
DRY AS CANADIAN ANTICYCLONE REMAINS LOCKED OVER THE REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 215 PM EDT SAT MAY 16 2015
LOTS OF WEAK ENERGY DISTURBANCES AND AREAS OF DIFFERENTIAL HEATING
ALLOWING DISORGANIZED BANDS OF SHOWERS AND A FEW STORMS TO DEVELOP
AND PERSIST OVER THE AREA. ALSO...MFR CLOUDS HANGING AROUND UNDER
A DEEP COLUMN OF MOISTURE WHICH WAS SATURATED OR NEARLY SATURATED
UP TO 400 MB AS INDICATED ON SOME ACARS/AFCT SOUNDINGS. REALLY
HARD TO PICK A TIME FOR SHOWERS OR A STORMS AT EITHER TAF SITE.
WENT FAIRLY CONSERVATIVE ON PLACING ANY SHOWERS OR STORMS AT TAF
SITES AS OVERALL SHOWER/STORM COVERAGE SHOULD NOT BE THAT GREAT.
HOWEVER... MADE TAFS MUCH MORE PESSIMISTIC WITH ANY CLEARING OF
MVFR CLOUDS. HAVE BROUGHT BOTH SBN AND FWA SITES DOWN TO LOW
MVFR... WITH THE POSSIBILITY INCREASING FOR IFR CONDITIONS AT SOME
POINT TONIGHT.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MCD/SKIPPER
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...SKIPPER
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1022 AM EDT SAT MAY 16 2015
.SYNOPSIS...
ISSUED AT 1021 AM EDT SAT MAY 16 2015
THE COMBINATION OF A STALLED FRONT ACROSS THE REGION AND A SERIES
OF UPPER LEVEL DISTURBANCES TRACKING ACROSS THE AREA WILL RESULT
IN SCATTERED SHOWERS AND THUNDERSTORMS TODAY AND TONIGHT. SHOWERS AND
THUNDERSTORMS WILL BECOME MORE LIKELY BY SUNDAY NIGHT AS A
STRONGER SYSTEM APPROACHES FROM THE WEST. OTHERWISE...WARM
CONDITIONS WILL CONTINUE THROUGH THE WEEKEND. HIGH TEMPERATURES
THIS AFTERNOON WILL REACH AROUND 80...WITH LOW TEMPERATURES
TONIGHT DROPPING INTO THE MIDDLE 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 402 AM EDT SAT MAY 16 2015
NORTHWARD SHIFT TO LOW/MID LEVEL THETAE GRADIENT WILL CONTINUE THIS
MORNING AS A SERIES OF SMALL SCALE SHORT WAVES LIFT INTO NORTHEAST
INDIANA. THE MOST PRONOUNCED OF THESE SMALL SCALE VORTICES APPEARS
TO BE TRACKING ACROSS CENTRAL INDIANA AT THIS TIME. THROUGH THE
EARLY MORNING HOURS HAVE INDICATED A SOUTH TO NORTH INCREASE IN POPS
FOLLOWING PROGRESSION OF SHORT WAVE FORCING/MOISTURE
ADVECTION...AND AN ISOLD THUNDER MENTION WITH STILL SOME 250-500
K/G MUCAPES ANALYZED PER LATEST RUC ANALYSIS FOR SLIGHTLY ELEVATED
PARCELS. COVERAGE OF SHOWERS AND ISOLATED THUNDER SHOULD GRADUALLY
WIND DOWN IN THE 12-14Z TIMEFRAME.
LOOKING UPSTREAM...ADDITIONAL WEAK SHORT WAVES WILL TEND TO SHEAR
WITH NORTHWARD EXTENT AS THEY ENTER THE LOCAL AREA FROM THE
LOWER/MID MS VALLEY THIS AFTERNOON. QUITE CHALLENGING TO CLEARLY
PICK OUT THESE UPSTREAM WAVES THIS MORNING...ALTHOUGH BULK OF
GUIDANCE WOULD SUGGEST SOUTH/SOUTHEAST LOCATIONS WITH MORE
FAVORABLE SHORT WAVE TRACK THROUGH THIS AFTERNOON. A MODEST
MID/UPPER LEVEL SPEED MAX IS ALSO EXPECTED TO LIFT ACROSS EAST
CENTRAL INDIANA/WESTERN OHIO THIS AFTERNOON WHICH MAY ALSO TEND TO
FOCUS BETTER CONVECTIVE CHANCES. HAVE CONTINUED WITH MID TO HIGH
CHANCE POPS THROUGH THE DAY WITH HIGHEST POPS FOCUSED ACROSS
SOUTHEAST THIRD OF THE AREA. INSTABILITY MAGNITUDES SHOULD BE
SOMEWHAT LESS THAN YESTERDAY AS LOW LEVEL THERMAL RIDGE IS
WEAKER...AND GENERALLY EXPECTING SURFACED BASED CAPES ON THE ORDER
OF 750-1500 J/KG THIS AFTERNOON. SHEAR ALSO IS EXPECTED TO BE ON THE
MARGINAL SIDE WITH THE POSSIBLE EXCEPTION OF FAR SOUTHEAST AREAS
WHERE AFOREMENTIONED MID/UPPER JET STREAK MAY PROMOTE DEEP LAYER
SHEAR VALUES APPROACHING THE 25-30 KNOT RANGE. THIS MAY HELP TO
CONCENTRATE SCATTERED CONVECTION WITH THE APPROACH OF THE NEXT
SHORT WAVE ACROSS THE SOUTHEAST THIRD...BUT SEVERE WEATHER IS NOT
EXPECTED. NO CHANGE TO PREVIOUS FORECAST WITH HIGHS AROUND 80 FOR
TODAY...ALTHOUGH IF GREATER CONVECTIVE COVERAGE IS ABLE TO BECOME
ESTABLISHED ACROSS THE SOUTH/SOUTHEAST...HIGHS MAY BE A BIT TOO
WARM.
FORECAST CONFIDENCE FOR TONIGHT IS RELATIVELY LOW GIVEN THE LOW
PREDICTABILITY WITH SMALLER SCALE WAVES IN SOUTHWEST FLOW...BUT
CURRENT INDICATIONS SUGGEST THE DEPARTING SHORT WAVE ACROSS
SOUTHEAST HALF OF THE AREA MAY PROVIDE BEST EVENING CHANCES ACROSS
THESE LOCATIONS. OTHERWISE...FORCING LOOKS QUITE MEAGER FOR MOST OF
THE NIGHT. MOIST AIR MASS/CLOUD COVER SHOULD KEEP TEMPS IN THE MID
60S FOR LOWS MOST LOCATIONS. SOME PATCHY FOG IS
POSSIBLE...PARTICULARLY ACROSS THE FAR NORTH IN CLOSER PROXIMITY TO
STALLED LOW LEVEL FRONT BUT WILL OMIT FROM FORECAST AT THIS TIME.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 402 AM EDT SAT MAY 16 2015
PRECIP CHANCES STEADILY INCREASE INTO LATE SUNDAY AS LARGE CUTOFF
LOW FINALLY BEGINS TO MAKE SOME EASTWARD PROGRESS. STILL A FAIR
AMOUNT OF UNCERTAINTY REGARDING EXACT TIMING AND EVOLUTION OF
NORTHEAST EJECTION THOUGH. MAIN VORTICITY LOBE WILL PASS WELL TO OUR
NORTHWEST WITH JUST A FEW TRAILING EMBEDDED SHORTWAVES TO SPARK
CONVECTION IN OUR CWA. LEANED TOWARD THE LATEST GFS SOLUTION WHICH
HAS SUPPORT FROM THE ECMWF...SEVERAL OF THE NEWEST HI-RES RUNS...AND
IS IN LINE WITH PREVIOUS FORECAST. EXPECT BEST CHANCES FOR RAIN
DURING THE LATE AFTERNOON AND EVENING WITH LITTLE PRECIP BEFORE 18Z.
AFOREMENTIONED MODELS SHOW DECENT SHORTWAVE/PREFRONTAL SURFACE
TROUGH LIFTING INTO THE GREAT LAKES AT THIS TIME...COMMENSURATE WITH
A NOTED SURGE IN LOW LEVEL THETA-E ON THE NOSE OF A 30-35 KT 850MB
JET. SHOULD ALSO BE ABLE TO CAPITALIZE ON SOME MODERATE
INSTABILITY...THOUGH IT WILL STEADILY WANE AFTER SUNSET.
STILL...WOULD LIKE TO SEE BETTER DEFINED SYNOPTIC FORCING AND MODEL
AGREEMENT BEFORE BOOSTING POP FORECAST AND WILL HOLD WITH LOW END
LIKELY FOR NOW. MIDLEVEL LAPSE RATES ARE A LITTLE BETTER (6-6.5
C/KM) BUT MLCAPE VALUES STILL STRUGGLE TO GET MUCH ABOVE 1000
J/KG...ESPECIALLY BY 00Z WHEN THE BETTER 0-6KM SHEAR SPREADS INTO
THE AREA. SEVERE RISK IS THEREFORE LOW...CONFINED MAINLY TO OUR
WESTERN HALF DURING THE EARLY EVENING PERIOD. STRONG WIND GUSTS AND
SMALL HAIL WOULD BE THE PRIMARY THREATS IF SEVERE WEATHER DOES OCCUR.
ACTUAL COLD FRONT WILL NOT CROSS THE AREA UNTIL MONDAY NIGHT SO
COULD STILL BE SOME RESIDUAL CONVECTION...ESPECIALLY OVER OUR
EASTERN COUNTIES...ON MONDAY. COVERAGE/CHANCES WILL DEPEND ON HOW
SUNDAY NIGHT`S PRECIP EVOLVES WITH A POSSIBILITY OUR AREA WILL BE
TOO "WORKED OVER" FOR WIDESPREAD PRECIP. LLJ WEAKENS AND VEERS BY
MONDAY MORNING WITH BEST MOISTURE CONVERGENCE SHUNTED TO OUR EAST.
SIMILARLY...INSTABILITY REMAINS ON THE MARGINAL SIDE AND SEVERE RISK
IS LOW. INHERITED CHANCE POPS SEEM APPROPRIATE...THOUGH WILL BUMP
THEM UP A BIT IN OUR FAR EASTERN COUNTIES WHERE SLIGHTLY BETTER
MOISTURE/INSTABILITY RESIDE. REST OF THE WEEK STILL LOOKING COOL AND
DRY AS CANADIAN ANTICYCLONE REMAINS LOCKED OVER THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 544 AM EDT SAT MAY 16 2015
THE COMBINATION OF LOW/MID LEVEL MOISTURE TRANSPORT AND SEVERAL
WEAK EMBEDDED WAVES IN SOUTHWEST FLOW HAS LED TO NARROW BAND OF
SHOWERS FROM KSBN TO NORTH OF KFWA EARLY THIS MORNING. THIS BAND
WILL LIFT NORTH OF KSBN BY 12Z. A LULL IS THEN EXPECTED IN TERMS
OF PRECIP COVERAGE FOR THE TERMINALS...ALTHOUGH ADDITIONAL
IMPULSES EJECTING OUT OF SOUTHERN MISSOURI/ARKANSAS WILL POSE A
THREAT FOR ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS FROM
LATE MORNING INTO THIS AFTERNOON. CURRENT INDICATIONS WOULD
SUGGEST A MORE FAVORABLE SHORT WAVE TRACK FOR NORTHEAST
INDIANA. THUS...GREATER CONVECTIVE COVERAGE MAY AFFECT KFWA LATER
THIS MORNING INTO THIS AFTERNOON. HOWEVER WITH LOW CONFIDENCE IN
TIMING AND POINT PROBABILITIES...WILL LIMIT MENTION TO VCSH AT
KFWA AT THIS TIME. LIGHT SOUTH WINDS THIS MORNING WILL BECOME
SOUTHWEST 10 TO 15 KNOTS WITH DIURNAL MIXING THIS MORNING...AND
THEN LIGHT SOUTH AGAIN TONIGHT. DID ADD SOME MVFR VSBYS AT KSBN
LATER TONIGHT IN CLOSER PROXIMITY TO OLD LOW LEVEL BOUNDARY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MCD
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...MARSILI
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSNORTHERNINDIANA
WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
611 AM EDT SAT MAY 16 2015
.SYNOPSIS...
ISSUED AT 136 AM EDT SAT MAY 16 2015
THE COMBINATION OF A STALLED FRONT ACROSS THE REGION AND A SERIES
OF UPPER LEVEL DISTURBANCES TRACKING ACROSS THE AREA WILL RESULT
IN A CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS TODAY AND
TONIGHT. SHOWERS AND THUNDERSTORMS WILL BECOME MORE LIKELY BY
SUNDAY NIGHT AS A STRONGER SYSTEM APPROACHES FROM THE WEST.
OTHERWISE...WARM CONDITIONS WILL CONTINUE THROUGH THE WEEKEND.
HIGH TEMPERATURES THIS AFTERNOON WILL REACH AROUND 80...WITH LOW
TEMPERATURES TONIGHT DROPPING INTO THE MIDDLE 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 402 AM EDT SAT MAY 16 2015
NORTHWARD SHIFT TO LOW/MID LEVEL THETAE GRADIENT WILL CONTINUE THIS
MORNING AS A SERIES OF SMALL SCALE SHORT WAVES LIFT INTO NORTHEAST
INDIANA. THE MOST PRONOUNCED OF THESE SMALL SCALE VORTICES APPEARS
TO BE TRACKING ACROSS CENTRAL INDIANA AT THIS TIME. THROUGH THE
EARLY MORNING HOURS HAVE INDICATED A SOUTH TO NORTH INCREASE IN POPS
FOLLOWING PROGRESSION OF SHORT WAVE FORCING/MOISTURE
ADVECTION...AND AN ISOLD THUNDER MENTION WITH STILL SOME 250-500
K/G MUCAPES ANALYZED PER LATEST RUC ANALYSIS FOR SLIGHTLY ELEVATED
PARCELS. COVERAGE OF SHOWERS AND ISOLATED THUNDER SHOULD GRADUALLY
WIND DOWN IN THE 12-14Z TIMEFRAME.
LOOKING UPSTREAM...ADDITIONAL WEAK SHORT WAVES WILL TEND TO SHEAR
WITH NORTHWARD EXTENT AS THEY ENTER THE LOCAL AREA FROM THE
LOWER/MID MS VALLEY THIS AFTERNOON. QUITE CHALLENGING TO CLEARLY
PICK OUT THESE UPSTREAM WAVES THIS MORNING...ALTHOUGH BULK OF
GUIDANCE WOULD SUGGEST SOUTH/SOUTHEAST LOCATIONS WITH MORE
FAVORABLE SHORT WAVE TRACK THROUGH THIS AFTERNOON. A MODEST
MID/UPPER LEVEL SPEED MAX IS ALSO EXPECTED TO LIFT ACROSS EAST
CENTRAL INDIANA/WESTERN OHIO THIS AFTERNOON WHICH MAY ALSO TEND TO
FOCUS BETTER CONVECTIVE CHANCES. HAVE CONTINUED WITH MID TO HIGH
CHANCE POPS THROUGH THE DAY WITH HIGHEST POPS FOCUSED ACROSS
SOUTHEAST THIRD OF THE AREA. INSTABILITY MAGNITUDES SHOULD BE
SOMEWHAT LESS THAN YESTERDAY AS LOW LEVEL THERMAL RIDGE IS
WEAKER...AND GENERALLY EXPECTING SURFACED BASED CAPES ON THE ORDER
OF 750-1500 J/KG THIS AFTERNOON. SHEAR ALSO IS EXPECTED TO BE ON THE
MARGINAL SIDE WITH THE POSSIBLE EXCEPTION OF FAR SOUTHEAST AREAS
WHERE AFOREMENTIONED MID/UPPER JET STREAK MAY PROMOTE DEEP LAYER
SHEAR VALUES APPROACHING THE 25-30 KNOT RANGE. THIS MAY HELP TO
CONCENTRATE SCATTERED CONVECTION WITH THE APPROACH OF THE NEXT
SHORT WAVE ACROSS THE SOUTHEAST THIRD...BUT SEVERE WEATHER IS NOT
EXPECTED. NO CHANGE TO PREVIOUS FORECAST WITH HIGHS AROUND 80 FOR
TODAY...ALTHOUGH IF GREATER CONVECTIVE COVERAGE IS ABLE TO BECOME
ESTABLISHED ACROSS THE SOUTH/SOUTHEAST...HIGHS MAY BE A BIT TOO
WARM.
FORECAST CONFIDENCE FOR TONIGHT IS RELATIVELY LOW GIVEN THE LOW
PREDICTABILITY WITH SMALLER SCALE WAVES IN SOUTHWEST FLOW...BUT
CURRENT INDICATIONS SUGGEST THE DEPARTING SHORT WAVE ACROSS
SOUTHEAST HALF OF THE AREA MAY PROVIDE BEST EVENING CHANCES ACROSS
THESE LOCATIONS. OTHERWISE...FORCING LOOKS QUITE MEAGER FOR MOST OF
THE NIGHT. MOIST AIR MASS/CLOUD COVER SHOULD KEEP TEMPS IN THE MID
60S FOR LOWS MOST LOCATIONS. SOME PATCHY FOG IS
POSSIBLE...PARTICULARLY ACROSS THE FAR NORTH IN CLOSER PROXIMITY TO
STALLED LOW LEVEL FRONT BUT WILL OMIT FROM FORECAST AT THIS TIME.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 402 AM EDT SAT MAY 16 2015
PRECIP CHANCES STEADILY INCREASE INTO LATE SUNDAY AS LARGE CUTOFF
LOW FINALLY BEGINS TO MAKE SOME EASTWARD PROGRESS. STILL A FAIR
AMOUNT OF UNCERTAINTY REGARDING EXACT TIMING AND EVOLUTION OF
NORTHEAST EJECTION THOUGH. MAIN VORTICITY LOBE WILL PASS WELL TO OUR
NORTHWEST WITH JUST A FEW TRAILING EMBEDDED SHORTWAVES TO SPARK
CONVECTION IN OUR CWA. LEANED TOWARD THE LATEST GFS SOLUTION WHICH
HAS SUPPORT FROM THE ECMWF...SEVERAL OF THE NEWEST HI-RES RUNS...AND
IS IN LINE WITH PREVIOUS FORECAST. EXPECT BEST CHANCES FOR RAIN
DURING THE LATE AFTERNOON AND EVENING WITH LITTLE PRECIP BEFORE 18Z.
AFOREMENTIONED MODELS SHOW DECENT SHORTWAVE/PREFRONTAL SURFACE
TROUGH LIFTING INTO THE GREAT LAKES AT THIS TIME...COMMENSURATE WITH
A NOTED SURGE IN LOW LEVEL THETA-E ON THE NOSE OF A 30-35 KT 850MB
JET. SHOULD ALSO BE ABLE TO CAPITALIZE ON SOME MODERATE
INSTABILITY...THOUGH IT WILL STEADILY WANE AFTER SUNSET.
STILL...WOULD LIKE TO SEE BETTER DEFINED SYNOPTIC FORCING AND MODEL
AGREEMENT BEFORE BOOSTING POP FORECAST AND WILL HOLD WITH LOW END
LIKELY FOR NOW. MIDLEVEL LAPSE RATES ARE A LITTLE BETTER (6-6.5
C/KM) BUT MLCAPE VALUES STILL STRUGGLE TO GET MUCH ABOVE 1000
J/KG...ESPECIALLY BY 00Z WHEN THE BETTER 0-6KM SHEAR SPREADS INTO
THE AREA. SEVERE RISK IS THEREFORE LOW...CONFINED MAINLY TO OUR
WESTERN HALF DURING THE EARLY EVENING PERIOD. STRONG WIND GUSTS AND
SMALL HAIL WOULD BE THE PRIMARY THREATS IF SEVERE WEATHER DOES OCCUR.
ACTUAL COLD FRONT WILL NOT CROSS THE AREA UNTIL MONDAY NIGHT SO
COULD STILL BE SOME RESIDUAL CONVECTION...ESPECIALLY OVER OUR
EASTERN COUNTIES...ON MONDAY. COVERAGE/CHANCES WILL DEPEND ON HOW
SUNDAY NIGHT`S PRECIP EVOLVES WITH A POSSIBILITY OUR AREA WILL BE
TOO "WORKED OVER" FOR WIDESPREAD PRECIP. LLJ WEAKENS AND VEERS BY
MONDAY MORNING WITH BEST MOISTURE CONVERGENCE SHUNTED TO OUR EAST.
SIMILARLY...INSTABILITY REMAINS ON THE MARGINAL SIDE AND SEVERE RISK
IS LOW. INHERITED CHANCE POPS SEEM APPROPRIATE...THOUGH WILL BUMP
THEM UP A BIT IN OUR FAR EASTERN COUNTIES WHERE SLIGHTLY BETTER
MOISTURE/INSTABILITY RESIDE. REST OF THE WEEK STILL LOOKING COOL AND
DRY AS CANADIAN ANTICYCLONE REMAINS LOCKED OVER THE REGION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 544 AM EDT SAT MAY 16 2015
THE COMBINATION OF LOW/MID LEVEL MOISTURE TRANSPORT AND SEVERAL
WEAK EMBEDDED WAVES IN SOUTHWEST FLOW HAS LED TO NARROW BAND OF
SHOWERS FROM KSBN TO NORTH OF KFWA EARLY THIS MORNING. THIS BAND
WILL LIFT NORTH OF KSBN BY 12Z. A LULL IS THEN EXPECTED IN TERMS
OF PRECIP COVERAGE FOR THE TERMINALS...ALTHOUGH ADDITIONAL
IMPULSES EJECTING OUT OF SOUTHERN MISSOURI/ARKANSAS WILL POSE A
THREAT FOR ADDITIONAL SCATTERED SHOWERS AND THUNDERSTORMS FROM
LATE MORNING INTO THIS AFTERNOON. CURRENT INDICATIONS WOULD
SUGGEST A MORE FAVORABLE SHORT WAVE TRACK FOR NORTHEAST
INDIANA. THUS...GREATER CONVECTIVE COVERAGE MAY AFFECT KFWA LATER
THIS MORNING INTO THIS AFTERNOON. HOWEVER WITH LOW CONFIDENCE IN
TIMING AND POINT PROBABILITIES...WILL LIMIT MENTION TO VCSH AT
KFWA AT THIS TIME. LIGHT SOUTH WINDS THIS MORNING WILL BECOME
SOUTHWEST 10 TO 15 KNOTS WITH DIURNAL MIXING THIS MORNING...AND
THEN LIGHT SOUTH AGAIN TONIGHT. DID ADD SOME MVFR VSBYS AT KSBN
LATER TONIGHT IN CLOSER PROXIMITY TO OLD LOW LEVEL BOUNDARY.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...MARSILI
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
404 AM EDT SAT MAY 16 2015
.SYNOPSIS...
ISSUED AT 136 AM EDT SAT MAY 16 2015
THE COMBINATION OF A STALLED FRONT ACROSS THE REGION AND A SERIES
OF UPPER LEVEL DISTURBANCES TRACKING ACROSS THE AREA WILL RESULT
IN A CONTINUED CHANCE OF SHOWERS AND THUNDERSTORMS TODAY AND
TONIGHT. SHOWERS AND THUNDERSTORMS WILL BECOME MORE LIKELY BY
SUNDAY NIGHT AS A STRONGER SYSTEM APPROACHES FROM THE WEST.
OTHERWISE...WARM CONDITIONS WILL CONTINUE THROUGH THE WEEKEND.
HIGH TEMPERATURES THIS AFTERNOON WILL REACH AROUND 80...WITH LOW
TEMPERATURES TONIGHT DROPPING INTO THE MIDDLE 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 402 AM EDT SAT MAY 16 2015
NORTHWARD SHIFT TO LOW/MID LEVEL THETAE GRADIENT WILL CONTINUE THIS
MORNING AS A SERIES OF SMALL SCALE SHORT WAVES LIFT INTO NORTHEAST
INDIANA. THE MOST PRONOUNCED OF THESE SMALL SCALE VORTICES APPEARS
TO BE TRACKING ACROSS CENTRAL INDIANA AT THIS TIME. THROUGH THE
EARLY MORNING HOURS HAVE INDICATED A SOUTH TO NORTH INCREASE IN POPS
FOLLOWING PROGRESSION OF SHORT WAVE FORCING/MOISTURE
ADVECTION...AND AN ISOLD THUNDER MENTION WITH STILL SOME 250-500
K/G MUCAPES ANALYZED PER LATEST RUC ANALYSIS FOR SLIGHTLY ELEVATED
PARCELS. COVERAGE OF SHOWERS AND ISOLATED THUNDER SHOULD GRADUALLY
WIND DOWN IN THE 12-14Z TIMEFRAME.
LOOKING UPSTREAM...ADDITIONAL WEAK SHORT WAVES WILL TEND TO SHEAR
WITH NORTHWARD EXTENT AS THEY ENTER THE LOCAL AREA FROM THE
LOWER/MID MS VALLEY THIS AFTERNOON. QUITE CHALLENGING TO CLEARLY
PICK THESE UPSTREAM WAVES OUT THIS MORNING...ALTHOUGH BULK OF
GUIDANCE WOULD SUGGEST SOUTH/SOUTHEAST LOCATIONS WITH MORE FAVORABLE
SHORT WAVE TRACK THIS AFTERNOON. A MODEST MID/UPPER LEVEL SPEED MAX
IS ALSO EXPECTED TO LIFT ACROSS EAST CENTRAL INDIANA/WESTERN OHIO
THIS AFTERNOON WHICH MAY ALSO TEND TO FOCUS BETTER CONVECTIVE
CHANCES. HAVE CONTINUED WITH MID TO HIGH CHANCE POPS THROUGH THE DAY
WITH HIGHEST POPS FOCUSED ACROSS SOUTHEAST THIRD OF THE AREA.
INSTABILITY MAGNITUDES SHOULD BE SOMEWHAT LESS THAN YESTERDAY AS LOW
LEVEL THERMAL RIDGE IS WEAKER...AND GENERALLY EXPECTING SURFACED
BASED CAPES ON THE ORDER OF 750-1500 J/KG THIS AFTERNOON. SHEAR ALSO
IS EXPECTED TO BE ON THE MARGINAL SIDE WITH THE POSSIBLE EXCEPTION
OF FAR SOUTHEAST AREAS WHERE AFOREMENTIONED MID/UPPER JET STREAK MAY
PROMOTE DEEP LAYER SHEAR VALUES APPROACHING THE 25-30 KNOT RANGE.
THIS MAY HELP TO CONCENTRATE SCATTERED CONVECTION WITH THE APPROACH
OF THE NEXT SHORT WAVE ACROSS THE SOUTHEAST THIRD...BUT SEVERE
WEATHER IS NOT EXPECTED. NO CHANGE TO PREVIOUS FORECAST WITH HIGHS
AROUND 80 FOR TODAY...ALTHOUGH IF GREATER CONVECTIVE COVERAGE IS
ABLE TO BECOME ESTABLISHED ACROSS THE SOUTH/SOUTHEAST...HIGHS MAY BE
A BIT TOO WARM.
FORECAST CONFIDENCE FOR TONIGHT IS RELATIVELY LOW GIVEN THE LOW
PREDICTABILITY WITH SMALLER SCALE WAVES IN SOUTHWEST FLOW...BUT
CURRENT INDICATIONS SUGGEST THE DEPARTING SHORT WAVE ACROSS
SOUTHEAST HALF OF THE AREA MAY PROVIDE BEST EVENING CHANCES ACROSS
THESE LOCATIONS. OTHERWISE...FORCING LOOKS QUITE MEAGER FOR MOST OF
THE NIGHT. MOIST AIR MASS/CLOUD COVER SHOULD KEEP TEMPS IN THE MID
60S FOR LOWS MOST LOCATIONS. SOME PATCHY FOG IS
POSSIBLE...PARTICULARLY ACROSS THE FAR NORTH IN CLOSER PROXIMITY TO
STALLED LOW LEVEL FRONT BUT WILL OMIT FROM FORECAST AT THIS TIME.
&&
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 402 AM EDT SAT MAY 16 2015
PRECIP CHANCES STEADILY INCREASE INTO LATE SUNDAY AS LARGE CUTOFF
LOW FINALLY BEGINS TO MAKE SOME EASTWARD PROGRESS. STILL A FAIR
AMOUNT OF UNCERTAINTY REGARDING EXACT TIMING AND EVOLUTION OF
NORTHEAST EJECTION THOUGH. MAIN VORTICITY LOBE WILL PASS WELL TO OUR
NORTHWEST WITH JUST A FEW TRAILING EMBEDDED SHORTWAVES TO SPARK
CONVECTION IN OUR CWA. LEANED TOWARD THE LATEST GFS SOLUTION WHICH
HAS SUPPORT FROM THE ECMWF...SEVERAL OF THE NEWEST HI-RES RUNS...AND
IS IN LINE WITH PREVIOUS FORECAST. EXPECT BEST CHANCES FOR RAIN
DURING THE LATE AFTERNOON AND EVENING WITH LITTLE PRECIP BEFORE 18Z.
AFOREMENTIONED MODELS SHOW DECENT SHORTWAVE/PREFRONTAL SURFACE
TROUGH LIFTING INTO THE GREAT LAKES AT THIS TIME...COMMENSURATE WITH
A NOTED SURGE IN LOW LEVEL THETA-E ON THE NOSE OF A 30-35 KT 850MB
JET. SHOULD ALSO BE ABLE TO CAPITALIZE ON SOME MODERATE
INSTABILITY...THOUGH IT WILL STEADILY WANE AFTER SUNSET.
STILL...WOULD LIKE TO SEE BETTER DEFINED SYNOPTIC FORCING AND MODEL
AGREEMENT BEFORE BOOSTING POP FORECAST AND WILL HOLD WITH LOW END
LIKELY FOR NOW. MIDLEVEL LAPSE RATES ARE A LITTLE BETTER (6-6.5
C/KM) BUT MLCAPE VALUES STILL STRUGGLE TO GET MUCH ABOVE 1000
J/KG...ESPECIALLY BY 00Z WHEN THE BETTER 0-6KM SHEAR SPREADS INTO
THE AREA. SEVERE RISK IS THEREFORE LOW...CONFINED MAINLY TO OUR
WESTERN HALF DURING THE EARLY EVENING PERIOD. STRONG WIND GUSTS AND
SMALL HAIL WOULD BE THE PRIMARY THREATS IF SEVERE WEATHER DOES OCCUR.
ACTUAL COLD FRONT WILL NOT CROSS THE AREA UNTIL MONDAY NIGHT SO
COULD STILL BE SOME RESIDUAL CONVECTION...ESPECIALLY OVER OUR
EASTERN COUNTIES...ON MONDAY. COVERAGE/CHANCES WILL DEPEND ON HOW
SUNDAY NIGHT`S PRECIP EVOLVES WITH A POSSIBILITY OUR AREA WILL BE
TOO "WORKED OVER" FOR WIDESPREAD PRECIP. LLJ WEAKENS AND VEERS BY
MONDAY MORNING WITH BEST MOISTURE CONVERGENCE SHUNTED TO OUR EAST.
SIMILARLY...INSTABILITY REMAINS ON THE MARGINAL SIDE AND SEVERE RISK
IS LOW. INHERITED CHANCE POPS SEEM APPROPRIATE...THOUGH WILL BUMP
THEM UP A BIT IN OUR FAR EASTERN COUNTIES WHERE SLIGHTLY BETTER
MOISTURE/INSTABILITY RESIDE. REST OF THE WEEK STILL LOOKING COOL AND
DRY AS CANADIAN ANTICYCLONE REMAINS LOCKED OVER THE REGION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 136 AM EDT SAT MAY 16 2015
UPPER LEVEL RIDGING WILL REBUILD ACROSS THE GREAT LAKES REGION
TODAY...ALTHOUGH SEVERAL SMALL SCALE DISTURBANCES IN SOUTHWEST
FLOW ALOFT COMBINED WITH WEAK TO MODERATE AFTERNOON INSTABILITY
MAY RESULT IN ISOLATED-SCATTERED SHOWERS AND THUNDERSTORMS. GIVEN
WEAK NATURE TO FORCING MECHANISMS AND INSTABILITY POSSIBLY A BIT
MORE TEMPERED IN COMPARISON TO YESTERDAY...HAVE OPTED TO CONTINUE
TO REFRAIN FROM ANY MENTION WITH THE 06Z TAFS DUE TO LOW
CONFIDENCE. THUNDER CHANCES TONIGHT APPEAR TO BE QUITE LOW GIVEN
WEAKENING INSTABILITY AND BETTER FORCING HOLDING OFF UNTIL AFTER
THIS FORECAST VALID PERIOD. SOME PATCHY FOG MAY FORM OVER THE NEXT
SEVERAL HOURS AND HAVE MAINTAINED TREND TO MVFR CONDITIONS IN THE
09Z-13Z TIMEFRAME. OTHERWISE...LIGHT SOUTH WINDS OVERNIGHT WILL
BECOME SOUTHWESTERLY AFTER 14Z WITH SOME GUSTS TO 15 TO 20 KNOTS
NOT OUT OF THE QUESTION. SOME MORE PATCHY FOG IS POSSIBLE AGAIN
FOR SATURDAY NIGHT...AND WILL ADDRESS THIS MORE FULLY WITH THE 12Z
TAFS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...MARSILI
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1127 PM CDT FRI MAY 15 2015
.SHORT TERM /TONIGHT/...
ISSUED AT 425 PM CDT FRI MAY 15 2015
LOW PRESSURE CONTINUES TO WORK ITS WAY OFF OF THE ROCKIES AND INTO
NE COLORADO AND SW NEBRASKA THIS AFTERNOON AND WILL BE THE MAIN
DRIVER OF WEATHER OVER THE WEEKEND...BUT NOT IN THIS PERIOD.
INSTEAD...VORTICITY ASSOCIATED WITH A SHORTWAVE MOVING UP THROUGH
THE PLAINS HAS KICKED OFF CONVECTION IN E KANSAS AND W AND C
MISSOURI. THETA-E ADVECTION IS NOT SIGNIFICANT WITH THE CONVECTION
IN KANSAS...BUT IS MORE SO IN MISSOURI AND IS EXPECTED TO INCREASE
LATER THIS AFTERNOON AND EVENING AS THE LOW LEVEL FLOW INCREASES AND
HELPS KEEP SHOWERS AND STORMS GOING AS DAYTIME HEATING AND
INSTABILITY BEGINS TO WANE. A FEW STORMS MAY CONTAIN SEVERE HAIL AND
HIGH WINDS EARLY THIS EVENING WITH CAPE VALUES IN EXCESS OF 1500-
2000 J/KG...WIDESPREAD SEVERE IS NOT EXPECTED THOUGH GIVEN THE LACK
OF SUPPORTIVE SHEAR. SHOWERS AND STORMS ARE ALREADY IN THE SW CWA
AND WILL CONTINUE TO MOVE NORTHEAST...REACHING THE DES MOINES METRO
AROUND 00Z...AND THE WATERLOO AROUND 03Z...WEAKENING AS THE EVENING
GOES ON. THE HIGH-RES MODELS HAVE NOT BEEN IN GREAT AGREEMENT...WITH
THE HRRR OVERLY AGGRESSIVE IN PROGRESSION. THE ARW-EAST HAS THE
BEST HANDLE ON CONVECTION CURRENTLY...AND HAVE LEANED THAT WAY FOR
POPS THIS EVENING. AM EXPECTING LOCALLY DENSE FOG OVERNIGHT...AS
WELL...WITH HIGH DEW PTS FROM INCOMING PRECIP AND SOLID MOISTURE
TRANSPORT THROUGH THE EVENING AND OVERNIGHT...BUT WILL REFRAIN
FROM WIDESPREAD FOR NOT AND DENOTE PATCHY FOG.
.LONG TERM /SATURDAY THROUGH FRIDAY/...
ISSUED AT 425 PM CDT FRI MAY 15 2015
DYNAMIC UPPER LEVEL SYSTEM EXTENDING FROM SOUTHERN CALIFORNIA
THROUGH IDAHO WILL SEGMENT INTO TWO SECTIONS WITH ONE SEGMENT
LIFTING INTO WYOMING AND MONTANA AND LINGERING THERE THROUGH
SUNDAY. THE STRONGER SEGMENT WILL MOVE EAST THROUGH THE DESERT
SOUTHWEST ON SUNDAY THEN LIFT NORTHEAST THROUGH THE TEXAS
PANHANDLE LATE SATURDAY THEN OVER EASTERN NEBRASKA BY EARLY
SUNDAY. THE INITIAL SHORTWAVE THAT WILL MOVE ACROSS IOWA OVERNIGHT
WILL LEAVE SOME STABILITY THROUGH THE MORNING WITH THE PASSAGE OF
MID LEVEL DRY AIR. INSTABILITY WILL DEVELOP BY THE AFTERNOON
THROUGH SFC HEATING HOWEVER NO GOOD FORCING MECHANISM WILL BE
AVAILABLE AND THIS SHOULD LIMIT THE AREAL COVERAGE OF THUNDERSTORM
DEVELOPMENT. THE STRONGER THUNDERSTORMS SATURDAY AFTERNOON AND
EVENING WILL INITIALIZE ACROSS NEBRASKA AND KANSAS. THESE STORMS
SHOULD MOVE INTO WESTERN IOWA SATURDAY NIGHT AS THE UPPER LEVEL
SYSTEM ADVANCES NORTHEAST. A FEW SEVERE STORMS ARE POSSIBLE AS
THIS ACTIVITY ARRIVES.
THE THUNDERSTORM POTENTIAL ON SUNDAY EARLY IN THE DAY WILL BE FROM
LINGERING ACTIVITY FROM THE OVERNIGHT. A BOUNDARY WILL MOVE
THROUGH IN THE MORNING AND WILL BRING DRIER AIR TO THE STATE.
TEMPERATURES SHOULD WARM IN TO THE 70S AND 80S BEHIND THE BOUNDARY
HOWEVER THUNDERSTORM CHANCES WILL BE LIMITED BY THE DRIER AIR. THE
BEST POTENTIAL FOR THUNDERSTORMS WILL BE ACROSS NORTHERN IOWA
DURING THE AFTERNOON IN CLOSER VICINITY TO THE UPPER LEVEL COLD
CORE. AN ATTENDANT HAIL THREAT WOULD BE POSSIBLE WITH ANY
AFTERNOON STORMS.
THE REMAINDER OF THE EXTENDED WILL BE COOL WITH 850 MB
TEMPERATURES IN THE 0-5C RANGE THROUGH WEDNESDAY. BREEZY AND COOL
CONDITIONS ON MONDAY. NOT EXPECTING ANY SHOWERS DESPITE THE
CYCLONIC FLOW WITH A GOOD INVERSION IN PLACE ABOVE THE BOUNDARY
LAYER. ANOTHER PUSH OF COOLER AIR TUESDAY NIGHT AND WEDNESDAY
ALONG WITH ANOTHER CHANCE FOR SHOWERS.
&&
.AVIATION...16/06Z
ISSUED AT 1127 PM CDT FRI MAY 15 2015
A FEW SHRA/TSRA ARE POSSIBLE OVERNIGHT...BUT COVERAGE TOO LOW FOR
INCLUSION IN THE TAFS. OTHERWISE...PRIMARY FORECAST CHALLENGE IS
THE POTENTIAL FOR FOG/STRATUS DEVELOPMENT OVERNIGHT. WITH DEWPTS
IN THE LOWER 60S AND LOW DEPRESSIONS THERE IS CLEARLY A RISK FOR
SUCH REDEVELOPMENT...HOWEVER...SATELLITE IMAGERY SHOWS PRETTY
SUBSTANTIAL MID/HIGH LEVEL CLOUDS OVERHEAD AND UPSTREAM...AND THE
SURFACE FLOW IS LIGHT BUT ORGANIZED OUT OF THE SOUTHEAST
MITIGATING THIS THREAT SOMEWHAT. ALSO NOTE THAT IT IS ALMOST
MIDNIGHT ALREADY AND ONLY ONE STATION IN IOWA IS REPORTING LOWER
THAN VFR CONDITIONS WITH ALL VSBYS UNRESTRICTED. HAVE THUS OPTED
TO GO WITH MVFR BR/CIGS OVERNIGHT BUT WILL BE CLOSELY MONITORING
OBSERVATIONAL TRENDS IN CASE AMENDMENTS BECOME NECESSARY.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...CURTIS
LONG TERM...DONAVON
AVIATION...LEE
***THIS FORECAST DISCUSSION FOCUSES ON SEVERE WEATHER POTENTIAL
TODAY...INCLUDING THE THREAT OF ANOTHER TORNADO OUTBREAK ACROSS THE
HIGH PLAINS.***
TODAY...WIDESPREAD OUTBREAK OF SEVERE WEATHER IS LIKELY AS MANY
PIECES COME TOGETHER. OVERALL...FEEL THIS IS ANOTHER DANGEROUS
SATURDAY WITH REGARDS TO SEVERE WEATHER AND CLOSE ATTENTION NEEDS TO
BE PAID TO LATEST FORECAST UPDATES. SURFACE LOW PRESSURE WILL
CONTINUE TO DEEPEN THROUGH THE AFTERNOON HOURS OVER SOUTHEAST
COLORADO WITH LITTLE ADVANCEMENT TO THE EAST FORECAST UNTIL AFTER
00Z/6 PM MDT. AHEAD OF THE SURFACE LOW...SOUTHEAST WINDS
INCREASE...BECOMING QUITE GUSTY. WITH THE POSITION OF THE LOW AND
INCREASING SOUTHEAST WINDS...DO NOT FORESEE AN OPPORTUNITY FOR THE
DRYLINE TO RACE EAST AS FORECAST BY MANY HIGH RESOLUTION GUIDANCE
MEMBERS. INSTEAD...HAVE USED THE LATEST NAM 12 AS THE BASIS FOR MY
FORECAST WHICH INDICATES A NEARLY STATIONARY DRYLINE. BY THIS
REASONING...MORE OF TRI-STATE REGION IS UNDER THREAT FOR A HIGHER
IMPACT DAY THAN PREVIOUSLY FORECAST. THIS THREAT MAY EVEN EXIST AS
FAR WEST AS PORTIONS OF NORTHEAST COLORADO.
THREATS:
THE THREATS TODAY ARE LARGE HAIL TO BASEBALL SIZE...DAMAGING WINDS
AS HIGH AS 70 MPH AND TORNADOES...SOME OF WHICH COULD BE
STRONG...LONG-TRACKED TORNADOES. HEAVY RAINS FROM TRAINING STORMS
ARE ALSO A CONCERN SO FLASH FLOODING IS A POSSIBILITY.
ADDITIONALLY...THESE STORMS WILL PROPAGATE QUICKLY WITH STORM
MOTIONS AS FAST AS 50 MPH POSSIBLE.
LOCATION:
THE HIGHEST CHANCE FOR VIOLENT SUPERCELL THUNDERSTORMS EXTENDS
GENERALLY EAST OF THE COLORADO BORDER. PLEASE SEE THE LATEST SPC
GRAPHICS FOR BETTER RESOLUTION AS WE STRONGLY AGREE WITH THEIR
ASSESSMENT FOR LOCATIONS OF THE ENHANCED AND MODERATE RISK AREAS.
TIMING:
THERE MAY BE A FEW ROUNDS OF SEVERE WEATHER THIS AFTERNOON. THE
FIRST...MOST SIGNIFICANT ROUND BEGINS SHORTLY AFTER NOON. THIS IS
WHEN SUPERCELL THUNDERSTORMS WILL DEVELOP ALONG THE DRYLINE AND
SPREAD EAST. ANOTHER LINE OF STORMS MAY DEVELOP ALONG THE DRYLINE
LATER IN THE AFTERNOON. FINALLY...SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP OVER CENTRAL COLORADO AND MOVE ON FROM THE WEST.
WHAT YOU NEED TO KNOW:
A TORNADO OUTBREAK SEEMS LIKELY TODAY FOR PORTIONS OF THE HIGH
PLAINS. CLOSE ATTENTION NEEDS TO BE PAID TO LATEST FORECAST UPDATES
AND WATCHES/WARNINGS AS THEY ARE ISSUED TODAY. STORMS...ONCE THEY
DEVELOP...WILL ALMOST INSTANTANEOUSLY BECOME SEVERE AND MOVE QUICKLY
NORTHEAST. RAPIDLY CHANGING CONDITIONS ARE EXPECTED SO PLEASE BE
AWARE OF THIS DEVELOPING WEATHER SITUATION.
.LONG TERM...(TUESDAY THROUGH FRIDAY)
ISSUED AT 327 AM MDT SAT MAY 16 2015
LATEST GUIDANCE CONTINUES TO INDICATE AN ACTIVE PATTERN ACROSS THE HIGH
PLAINS TUESDAY THROUGH SATURDAY. AN UPPER LEVEL LOW WILL MOVE OUT OF
THE SOUTHWEST ON TUESDAY AND DEEPEN... CREATING A NEGATIVE TROUGH THAT
WILL MOVE NORTHEAST INTO THE REGION AS WE HEAD INTO WEDNESDAY. THE 0-
6KM SHEAR PROFILE IS STRONG WITH 55-65KT ON TUESDAY AND WEDNESDAY AS
INDICATED BY BOTH THE GFS AND ECMWF. CAPE VALUES CONTINUE TO
REMAIN MODEST WITH THE GLOBAL MODELS INDICATING 200-400 J/KG AT
BEST. THE LOW WILL MOVE NORTHWARD THROUGH THE DAY ON WEDNESDAY AND
THURSDAY WHICH WILL KEEP POPS IN THE REGION IN THE 20-40 PERCENT
RANGE. THE DEVELOPMENT OF SEVERE STORMS WILL BE LIMITED DUE TO THE
LOW CAPE AND WEAK THETA-E GRADIENTS HOWEVER WE CANNOT RULE OUT
STRONGER THUNDERSTORM DEVELOPMENT AS THE HIGH SHEAR REMAINS IN
PLACE.
A PERSISTENT TROUGH REMAINS IN PLACE IN THE SOUTHWEST LATE THURSDAY AND
EARLY FRIDAY. EARLY GUIDANCE FROM THE GFS AND ECMWF INDICATE A STRONG
LOW MOVING SOUTHEASTWARD OUT OF THE PACIFIC LATE FRIDAY AND INTO
SATURDAY WHICH WILL REINFORCE AND DEEPEN THIS TROUGH. AT THE SAME TIME
LONG FETCH RETURN FLOW WILL INCREASE CAPE VALUES ACROSS THE HIGH
PLAINS. CAPE VALUES ON SATURDAY WILL INCREASE TO 800-1200 J/KG WITH
LIMITED SHEAR OF 30-40KTS MAINLY IN THE SOUTHERN AREAS OF THE CWA. IT
IS VERY EARLY STILL HOWEVER WE CANNOT RULE OUT THE POSSIBILITY OF
SEVERE THUNDERSTORMS NEXT SATURDAY AND SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1139 AM MDT SAT MAY 16 2015
BOTH TAF SITES WILL BEGIN TO SEE TRW DEVELOPMENT THIS AFTERNOON IN
THE VICINITY OF EACH AIRPORT...LASTING INTO THE EVENING HOURS.
BETTER POTENTIAL IS FOR KMCK BY 00Z TONIGHT...WITH HEAVY TRW
POSSIBLE FOR A COUPLE OF HOURS. BY 06Z...TRW ACTIVITY WILL
DIMINISH WITH VCSH FOR A COUPLE HOURS. OVERALL...MAINLY VFR
CONDITIONS IN SCT050-070 UNLESS THUNDER DEVELOPS. WINDS WILL BEGIN
AT SSW 20-30KTS...BECOMING WNW AT KGLD BY 02Z SUNDAY AT
15-25KTS...ESPECIALLY AFT 11Z SUNDAY. FOR KMCK...SSW WINDS BEGIN
BACKING TO THE SE THRU 00Z TONIGHT THEN SHIFT TO THE WNW BY 06Z
TONIGHT AS LOW PRESSURE PASSES REGION...WITH 15-25KTS MAINLY AFTER
16Z SUNDAY...5-15KTS BEFORE THAT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JN
SHORT TERM...RRH
LONG TERM...TML
AVIATION...JN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
205 PM CDT SAT MAY 16 2015
...UPDATED LONG TERM SECTION...
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 128 PM CDT SAT MAY 16 2015
ABBREVIATED SHORT TERM WITH MET WATCH. MADE ADJUSTMENTS TO POPS
CONCERNING THE NON SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL
KANSAS EARLY THIS AFTERNOON. SOME OF THE ACTIVITY ACROSS OKLAHOMA
HAS BEEN INCREASING IN INTENSITY, SO WILL HAVE TO WATCH OUT FOR
MARGINALLY SEVERE BASICALLY SE OF A LINE FROM ASHLAND TO ST JOHN.
THE NEXT AREA OF CONCERN IS OUT WEST. BUBBLING CUMULUS HAS BEEN
NOTED ON VIS SAT. TOOK A BLEND OF THE HRRR AND WRF-ARW FOR POP
ARRANGEMENTS WITH THIS ACTIVITY. WE LAUNCHED AN 18Z RAOB, WHICH
LOOKS FAR FROM SPECTACULAR. FIRST, INSTABILITY IS OBVIOUSLY VERY
LIMITED WITH ALL LINGERING CLOUD COVER. SECOND, 850-HPA WINDS ARE
VERY WEAK. IN FACT, THE ENTIRE LOW LEVELS ARE WEAK, ALTHOUGH
THERE IS DECENT VEERING. THIRDLY, UPPER LEVEL WINDS ARE BACKED.
TRANSLATION: MESSY HP SUPERCELLS. SO THE SITUATION HAS CHANGED A
BIT FROM PREVIOUSLY THOUGHT. THE MORNING SHOWERS AND THUNDERSTORMS
WILL PROBABLY HAVE DELETERIOUS IMPACTS TO STORM INTENSITY. RAP
ANALYSIS DOES SHOW CAPE INCREASING OUT WEST. STILL THINK WE WILL
STILL SEE SEVERE. THINK TORNADO POTENTIAL IS NOT AS HIGH AS
PREVIOUSLY THOUGH. THERE IS ENOUGH SHEAR TO GET ROTATING STORMS
THOUGH AND A FEW TORNADOES ARE NOT OUT OF THE QUESTION. WHAT IS
IN QUESTION IS IF THE TORNADOES WILL BE STRONG OR NOT. HAVE SEEN
AN UPTICK ON UPDRAFT HELICITY RECENTLY, SO SOMETHING TO MONITOR.
FROM THE 18Z RAOB, IT WILL TAKE QUITE THE ATMOSPHERIC TURN OVER
TO GET IT PRIMED FOR STRONG TORNADOES WITH DECENT INSTABILITY AND
STRENGTHENING LOW LEVEL WINDS. THERE IS SOME CONCERN ACROSS SOUTH-
CENTRAL KANSAS THAT LOW LEVEL WINDS THIS EVENING WILL STRENGTHEN
AND THE TORNADO POTENTIAL COULD GO UP. BUT BY THAT TIME, THE
STORMS COULD BE OUTFLOWY, PRECIPITATION LADEN MESSY STORMS. WILL
CONTINUE TO MONITOR THE MESOSCALE SITUATION AND ADJUST AS
NECESSARY. STORMS WILL BE MOVING AT A GOOD CLIP TOO.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 156 PM CDT SAT MAY 16 2015
THE SOUTHERN BRANCH OF THE WESTERLIES WILL CONTINUE TO BE ACTIVE
WITH AMPLIFICATION RESULTING FROM TROPICAL CONVECTION ACROSS THE
WESTERN PACIFIC. SUNDAY AND MONDAY WILL BE BETWEEN SYSTEMS AND THE
ONLY FORECAST CHALLENGE WILL BE TEMPERATURES AS ACTIVELY GROWING
VEGETATION AND WET SOILS WILL IMPACT TEMPERATURES.
THE NORTHERN BRANCH OF THE WESTERLIES WILL ALLOW SFC HIGH
PRESSURE TO BUILD INTO THE AREA MONDAY. WITH THE APPROACH OF
ANOTHER S/WV TROUGH IN THE SOUTHERN BRANCH, THE MOIST BOUNDARY
LAYER AIR SHOULD BE MOVING BACK NORTHWEST INTO THE HIGHER TERRAIN.
WIDESPREAD CONVECTION SHOULD RESULT BY TUESDAY AND INTO WEDNESDAY.
YET ANOTHER SYSTEM IS EXPECTED TOWARDS NEXT WEEKEND WITH
ADDITIONAL PCPN EXPECTED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1200 PM CDT SAT MAY 16 2015
CIGS SHOULD BE PRIMARILY VFR. CANNOT RULE OUT TEMPORARY IFR
CONDITIONS LATER THIS AFTERNOON IN ASSOCIATION WITH +TSRA. THIS
WILL BE LOCALIZED AND NOT THE PREVAILING FLIGHT CATEGORY. WILL
CONTINUE WITH CB/VCTS GROUPS FOR KHYS AND KGCK AND USE A TEMPO
GROUP FOR KDDC FOR STORMS THIS EVENING. SOUTHERLY WINDS 15-25 KT
TODAY WILL BECOME SOUTHWESTERLY 10-15 KT THROUGH THE OVERNIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 52 82 49 70 / 70 0 0 10
GCK 50 80 47 69 / 60 0 0 0
EHA 48 79 47 69 / 10 0 0 0
LBL 50 81 50 73 / 20 0 0 0
HYS 53 80 48 67 / 80 0 0 0
P28 56 83 54 76 / 80 0 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...HUTTON
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
128 PM CDT SAT MAY 16 2015
...UPDATED SHORT TERM...
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 128 PM CDT SAT MAY 16 2015
ABBREVIATED SHORT TERM WITH MET WATCH. MADE ADJUSTMENTS TO POPS
CONCERNING THE NON SEVERE THUNDERSTORMS ACROSS SOUTH-CENTRAL
KANSAS EARLY THIS AFTERNOON. SOME OF THE ACTIVITY ACROSS OKLAHOMA
HAS BEEN INCREASING IN INTENSITY, SO WILL HAVE TO WATCH OUT FOR
MARGINALLY SEVERE BASICALLY SE OF A LINE FROM ASHLAND TO ST JOHN.
THE NEXT AREA OF CONCERN IS OUT WEST. BUBBLING CUMULUS HAS BEEN
NOTED ON VIS SAT. TOOK A BLEND OF THE HRRR AND WRF-ARW FOR POP
ARRANGEMENTS WITH THIS ACTIVITY. WE LAUNCHED AN 18Z RAOB, WHICH
LOOKS FAR FROM SPECTACULAR. FIRST, INSTABILITY IS OBVIOUSLY VERY
LIMITED WITH ALL LINGERING CLOUD COVER. SECOND, 850-HPA WINDS ARE
VERY WEAK. IN FACT, THE ENTIRE LOW LEVELS ARE WEAK, ALTHOUGH
THERE IS DECENT VEERING. THIRDLY, UPPER LEVEL WINDS ARE BACKED.
TRANSLATION: MESSY HP SUPERCELLS. SO THE SITUATION HAS CHANGED A
BIT FROM PREVIOUSLY THOUGHT. THE MORNING SHOWERS AND THUNDERSTORMS
WILL PROBABLY HAVE DELETERIOUS IMPACTS TO STORM INTENSITY. RAP
ANALYSIS DOES SHOW CAPE INCREASING OUT WEST. STILL THINK WE WILL
STILL SEE SEVERE. THINK TORNADO POTENTIAL IS NOT AS HIGH AS
PREVIOUSLY THOUGH. THERE IS ENOUGH SHEAR TO GET ROTATING STORMS
THOUGH AND A FEW TORNADOES ARE NOT OUT OF THE QUESTION. WHAT IS
IN QUESTION IS IF THE TORNADOES WILL BE STRONG OR NOT. HAVE SEEN
AN UPTICK ON UPDRAFT HELICITY RECENTLY, SO SOMETHING TO MONITOR.
FROM THE 18Z RAOB, IT WILL TAKE QUITE THE ATMOSPHERIC TURN OVER
TO GET IT PRIMED FOR STRONG TORNADOES WITH DECENT INSTABILITY AND
STRENGTHENING LOW LEVEL WINDS. THERE IS SOME CONCERN ACROSS SOUTH-
CENTRAL KANSAS THAT LOW LEVEL WINDS THIS EVENING WILL STRENGTHEN
AND THE TORNADO POTENTIAL COULD GO UP. BUT BY THAT TIME, THE
STORMS COULD BE OUTFLOWY, PRECIPITATION LADEN MESSY STORMS. WILL
CONTINUE TO MONITOR THE MESOSCALE SITUATION AND ADJUST AS
NECESSARY. STORMS WILL BE MOVING AT A GOOD CLIP TOO.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 234 AM CDT SAT MAY 16 2015
FAIR WEATHER CAN BE EXPECTED SUNDAY IN THE WAKE OF THE
AFOREMENTIONED UPPER LEVEL TROUGH, ALONG WITH 10-15 KT SOUTHWEST
WINDS AND HIGHS IN THE UPPER 70S TO MID 80S. ANOTHER STRONG UPPER
LEVEL STORM SYSTEM WILL PROGRESS INTO THE SOUTHWESTERN UNITED
STATES BY LATE MONDAY, AND AHEAD OF THIS FEATURE, A COLD FRONT
WILL PASS THROUGH WESTERN KANSAS. HIGH TEMPERATURES WILL FALL INTO
THE UPPER 60S MONDAY NEAR INTERSTATE 70, WITH MID 70S IN SOUTH
CENTRAL KANSAS. AS THE NEXT UPPER LEVEL STORM SYSTEM APPROACHES ON
TUESDAY, LOW LEVEL MOISTURE WILL INCREASE, LEADING TO INCREASED
CHANCES FOR SHOWERS AND THUNDERSTORMS TUESDAY AND TUESDAY NIGHT.
HIGH-END SEVERE STORMS ARE NOT EXPECTED GIVEN THE COOL AIRMASS IN
PLACE ACROSS WESTERN KANSAS, BUT MARGINALLY SEVERE ELEVATED
THUNDERSTORMS CANNOT BE RULED OUT. HIGH TEMPERATURES WILL PROBABLY
BE IN THE UPPER 50S TO 60S TUESDAY.
ANOTHER BREAK IN THE RAIN MAY WILL PROBABLY OCCUR WEDNESDAY AND
THURSDAY BEFORE THE NEXT UPPER LEVEL SYSTEM APPROACHES FROM THE
WEST. HIGHS OUGHT TO BE IN THE 60S TO LOWER 70S WITH LOWS IN THE
40S TO LOWER 50S. WIDESPREAD SHOWERS AND THUNDERSTORMS CAN BE
EXPECTED WITH THIS SYSTEM FRIDAY AND SATURDAY; AND SOME OF THE
STORMS SATURDAY MAY BE SEVERE AS WARMER AND MOIST AIR MOVES INTO
WESTERN KANSAS FROM THE SOUTH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1200 PM CDT SAT MAY 16 2015
CIGS SHOULD BE PRIMARILY VFR. CANNOT RULE OUT TEMPORARY IFR
CONDITIONS LATER THIS AFTERNOON IN ASSOCIATION WITH +TSRA. THIS
WILL BE LOCALIZED AND NOT THE PREVAILING FLIGHT CATEGORY. WILL
CONTINUE WITH CB/VCTS GROUPS FOR KHYS AND KGCK AND USE A TEMPO
GROUP FOR KDDC FOR STORMS THIS EVENING. SOUTHERLY WINDS 15-25 KT
TODAY WILL BECOME SOUTHWESTERLY 10-15 KT THROUGH THE OVERNIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 52 82 49 70 / 70 0 0 10
GCK 50 80 47 69 / 60 0 0 0
EHA 48 79 47 69 / 10 0 0 0
LBL 50 81 50 73 / 20 0 0 0
HYS 53 80 48 67 / 80 0 0 0
P28 56 83 54 76 / 80 0 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...SUGDEN
LONG TERM...FINCH
AVIATION...SUGDEN
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1236 PM CDT Sat May 16 2015
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 346 AM CDT SAT MAY 16 2015
A broad upper level low was located across NV, UT and AZ early this
morning. A 65KT mid level jet max was lifting northeast across
eastern NM into western KS. The strong ascent ahead of this jet max
has helped to develop a line of showers and thunderstorms from
central NE, south-southwest into west TX. Most numerical models show
this line weakening as it moves east into a more stable airmass
across eastern KS through the morning hours.
A stronger H5 trough located along the southern base of the upper
level low will lift northeast across eastern NM into the northern TX
PNHDL through the late morning hours. Several numerical models all
show an area of scattered to numerous thunderstorms developing ahead
of a surface dryline across the eastern TX PNHDL through the mid
and late morning hours. These storms lift northeast and intensify
through the early and mid afternoon hours, as they move northeast
across western OK into south central KS. The 5Z HRRR shows this area
of thunderstorms moving northeast into the western counties of the
CWA by 20Z. Most numerical models show the atmosphere destabilizing
early this afternoon across the CWA, after the weaker storms from
this morning dissipate or lift off to the northeast. the WRF runs,
NAM and HRRR show SBCAPE of 2500 to 3500 J/KG. The 0-1KM shear looks
fairly weak with most models forecasting less than 100m2/s2 of 0-1KM
SRH. SFC to 6KM effective shear will be increasing to 40 to 60 KTS
during the afternoon. Therefore, the environment will be favorable
for severe thunderstorms this afternoon. Another question will be
the mode of convection. If a complex of storms develops across
northwest OK late this morning and maintains itself northeast
across the CWA than any tornado threat will be quite low. Though
stronger updrafts within a QLCS or complex of thunderstorms would
produce large hail and damaging wind gusts. The HRRR and NAM 4KM
simulated reflectivity forecast more scattered to isolated
thunderstorms developing across north central OK and south central
KS early this afternoon, and moving northeast into the southwest
and southern counties of the CWA after 22Z. I suppose if we see
discrete supercells than there will be a chance for tornadoes
along with the large hail and damaging wind gusts.
Late this afternoon most models show thunderstorms developing along
the Pacific front/dryline across west central KS and western OK. The
environment will really improve ahead of the dryline late this
afternoon, with much stronger low-level vertical wind shear. Any
discrete supercells that develop along the Pacific front/dryline
across west central KS and western OK will have a chance to produce
tornadoes. Through the evening hours these discrete to scattered
supercell thunderstorms may congeal into line segments or a QLCS and
move northeast into the western counties of the CWA during the mid
evening hours. If discrete supercells move into the western counties
this evening, then there will be a chance for tornadoes. I suppose
if a QLCS develops there is a potential for meso-vortices tornadoes.
Cloud cover will probably keep high temperatures in the mid to
upper 70s.
Tonight, The upper low and lead H5 trough will lift northeast into
southwest NE. Line segments of thunderstorms or a QLCS will move
east across the remainder of the CWA during the late evening hours
into the early morning hours of Sunday. The primary hazard will be
large hail, damaging winds and heavy rainfall.
.LONG TERM...(Sunday through Friday)
Issued at 346 AM CDT SAT MAY 16 2015
On Sunday the dry slot will work across the area with lower
dewpoints but daytime highs should still reach to around 80 given
mixing and expected sun. The cold front will finally move across
the area Sunday night and it should pass through dry however there
are some signals that precip may develop along it toward Mon
morning southeast of the area. For now will keep conds dry and
with CAA on Monday expect much cooler highs and lower humidities
as dewpoints fall into the 40s. Tues should also remain dry for
most of the day with rain expected to overspread the area Tues
night and last through Weds. Limited CAPE suggests only isolated
thunder but look for another widespread soaking rain out of this
system.
Perhaps a brief dry spell on Thursday before the next upper wave
approaches for late next week into next weekend. This system looks
very similar to this weekends so an active pattern will continue.
&&
.AVIATION...(For the 18Z TAFs through 18Z Sunday Afternoon)
Issued at 1234 PM CDT SAT MAY 16 2015
Sites have cleared to VFR after a line of showers moved through the
area this morning. VFR should continue until a line of storms moves
from SW to NE this afternoon into tonight impacting all terminals. Exact
timing and coverage of these storms is still uncertain, and have
continued to use VCTS for this reason. Storms will clear overnight
into tomorrow morning from W to E. After this clearing VFR will
prevail.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Omitt
AVIATION...Heller
AREA FORECAST DISCUSSION
NWS TOPEKA KS
634 AM CDT Sat May 16 2015
...Update to aviation forecast discussion...
.SHORT TERM...(Today and Tonight)
Issued at 346 AM CDT SAT MAY 16 2015
A broad upper level low was located across NV, UT and AZ early this
morning. A 65KT mid level jet max was lifting northeast across
eastern NM into western KS. The strong ascent ahead of this jet max
has helped to develop a line of showers and thunderstorms from
central NE, south-southwest into west TX. Most numerical models show
this line weakening as it moves east into a more stable airmass
across eastern KS through the morning hours.
A stronger H5 trough located along the southern base of the upper
level low will lift northeast across eastern NM into the northern TX
PNHDL through the late morning hours. Several numerical models all
show an area of scattered to numerous thunderstorms developing ahead
of a surface dryline across the eastern TX PNHDL through the mid
and late morning hours. These storms lift northeast and intensify
through the early and mid afternoon hours, as they move northeast
across western OK into south central KS. The 5Z HRRR shows this area
of thunderstorms moving northeast into the western counties of the
CWA by 20Z. Most numerical models show the atmosphere destabilizing
early this afternoon across the CWA, after the weaker storms from
this morning dissipate or lift off to the northeast. the WRF runs,
NAM and HRRR show SBCAPE of 2500 to 3500 J/KG. The 0-1KM shear looks
fairly weak with most models forecasting less than 100m2/s2 of 0-1KM
SRH. SFC to 6KM effective shear will be increasing to 40 to 60 KTS
during the afternoon. Therefore, the environment will be favorable
for severe thunderstorms this afternoon. Another question will be
the mode of convection. If a complex of storms develops across
northwest OK late this morning and maintains itself northeast
across the CWA than any tornado threat will be quite low. Though
stronger updrafts within a QLCS or complex of thunderstorms would
produce large hail and damaging wind gusts. The HRRR and NAM 4KM
simulated reflectivity forecast more scattered to isolated
thunderstorms developing across north central OK and south central
KS early this afternoon, and moving northeast into the southwest
and southern counties of the CWA after 22Z. I suppose if we see
discrete supercells than there will be a chance for tornadoes
along with the large hail and damaging wind gusts.
Late this afternoon most models show thunderstorms developing along
the Pacific front/dryline across west central KS and western OK. The
environment will really improve ahead of the dryline late this
afternoon, with much stronger low-level vertical wind shear. Any
discrete supercells that develop along the Pacific front/dryline
across west central KS and western OK will have a chance to produce
tornadoes. Through the evening hours these discrete to scattered
supercell thunderstorms may congeal into line segments or a QLCS and
move northeast into the western counties of the CWA during the mid
evening hours. If discrete supercells move into the western counties
this evening, then there will be a chance for tornadoes. I suppose
if a QLCS develops there is a potential for meso-vortices tornadoes.
Cloud cover will probably keep high temperatures in the mid to
upper 70s.
Tonight, The upper low and lead H5 trough will lift northeast into
southwest NE. Line segments of thunderstorms or a QLCS will move
east across the remainder of the CWA during the late evening hours
into the early morning hours of Sunday. The primary hazard will be
large hail, damaging winds and heavy rainfall.
.LONG TERM...(Sunday through Friday)
Issued at 346 AM CDT SAT MAY 16 2015
On Sunday the dry slot will work across the area with lower
dewpoints but daytime highs should still reach to around 80 given
mixing and expected sun. The cold front will finally move across
the area Sunday night and it should pass through dry however there
are some signals that precip may develop along it toward Mon
morning southeast of the area. For now will keep conds dry and
with CAA on Monday expect much cooler highs and lower humidities
as dewpoints fall into the 40s. Tues should also remain dry for
most of the day with rain expected to overspread the area Tues
night and last through Weds. Limited CAPE suggests only isolated
thunder but look for another widespread soaking rain out of this
system.
Perhaps a brief dry spell on Thursday before the next upper wave
approaches for late next week into next weekend. This system looks
very similar to this weekends so an active pattern will continue.
&&
.AVIATION...(For the 12Z TAFs through 12Z Sunday Morning)
Issued at 633 AM CDT SAT MAY 16 2015
Currently, TOP/FOE are varying between VFR/MVFR conditions. Have
kept prevailing VFR with a tempo MVFR group until 15Z to account for
this. At MHK, MVFR conditions are expected to prevail until 19Z
when ceilings will lift slightly. A line of TSRA moving slowly east
this morning and may reach terminals before weakening, so have
mentioned VCTS starting at 15Z at MHK and 17Z at FOE/TOP. The main
storms today should be in the afternoon, but timing in hard to
pinpoint so have included only VCTS at this time.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Omitt
AVIATION...Heller
AREA FORECAST DISCUSSION
NWS TOPEKA KS
400 AM CDT Sat May 16 2015
.SHORT TERM...(Today and Tonight)
Issued at 346 AM CDT SAT MAY 16 2015
A broad upper level low was located across NV, UT and AZ early this
morning. A 65KT mid level jet max was lifting northeast across
eastern NM into western KS. The strong ascent ahead of this jet max
has helped to develop a line of showers and thunderstorms from
central NE, south-southwest into west TX. Most numerical models show
this line weakening as it moves east into a more stable airmass
across eastern KS through the morning hours.
A stronger H5 trough located along the southern base of the upper
level low will lift northeast across eastern NM into the northern TX
PNHDL through the late morning hours. Several numerical models all
show an area of scattered to numerous thunderstorms developing ahead
of a surface dryline across the eastern TX PNHDL through the mid
and late morning hours. These storms lift northeast and intensify
through the early and mid afternoon hours, as they move northeast
across western OK into south central KS. The 5Z HRRR shows this area
of thunderstorms moving northeast into the western counties of the
CWA by 20Z. Most numerical models show the atmosphere destabilizing
early this afternoon across the CWA, after the weaker storms from
this morning dissipate or lift off to the northeast. the WRF runs,
NAM and HRRR show SBCAPE of 2500 to 3500 J/KG. The 0-1KM shear looks
fairly weak with most models forecasting less than 100m2/s2 of 0-1KM
SRH. SFC to 6KM effective shear will be increasing to 40 to 60 KTS
during the afternoon. Therefore, the environment will be favorable
for severe thunderstorms this afternoon. Another question will be
the mode of convection. If a complex of storms develops across
northwest OK late this morning and maintains itself northeast
across the CWA than any tornado threat will be quite low. Though
stronger updrafts within a QLCS or complex of thunderstorms would
produce large hail and damaging wind gusts. The HRRR and NAM 4KM
simulated reflectivity forecast more scattered to isolated
thunderstorms developing across north central OK and south central
KS early this afternoon, and moving northeast into the southwest
and southern counties of the CWA after 22Z. I suppose if we see
discrete supercells than there will be a chance for tornadoes
along with the large hail and damaging wind gusts.
Late this afternoon most models show thunderstorms developing along
the Pacific front/dryline across west central KS and western OK. The
environment will really improve ahead of the dryline late this
afternoon, with much stronger low-level vertical wind shear. Any
discrete supercells that develop along the Pacific front/dryline
across west central KS and western OK will have a chance to produce
tornadoes. Through the evening hours these discrete to scattered
supercell thunderstorms may congeal into line segments or a QLCS and
move northeast into the western counties of the CWA during the mid
evening hours. If discrete supercells move into the western counties
this evening, then there will be a chance for tornadoes. I suppose
if a QLCS develops there is a potential for meso-vortices tornadoes.
Cloud cover will probably keep high temperatures in the mid to
upper 70s.
Tonight, The upper low and lead H5 trough will lift northeast into
southwest NE. Line segments of thunderstorms or a QLCS will move
east across the remainder of the CWA during the late evening hours
into the early morning hours of Sunday. The primary hazard will be
large hail, damaging winds and heavy rainfall.
.LONG TERM...(Sunday through Friday)
Issued at 346 AM CDT SAT MAY 16 2015
On Sunday the dry slot will work across the area with lower
dewpoints but daytime highs should still reach to around 80 given
mixing and expected sun. The cold front will finally move across
the area Sunday night and it should pass through dry however there
are some signals that precip may develop along it toward Mon
morning southeast of the area. For now will keep conds dry and
with CAA on Monday expect much cooler highs and lower humidities
as dewpoints fall into the 40s. Tues should also remain dry for
most of the day with rain expected to overspread the area Tues
night and last through Weds. Limited CAPE suggests only isolated
thunder but look for another widespread soaking rain out of this
system.
Perhaps a brief dry spell on Thursday before the next upper wave
approaches for late next week into next weekend. This system looks
very similar to this weekends so an active pattern will continue.
&&
.AVIATION...(For the 06Z TAFs through 06Z Saturday Night)
Issued at 1148 PM CDT FRI MAY 15 2015
VFR prevails initially with increased low level moisture bringing
in a MVFR stratus deck with haze closer to 10Z according to short
term guidance. Line of TSRA in central KS is forecast to weaken
west of terminals and will need to monitor trends. Scattered TSRA
are possible after 15Z at KTOP/KFOE where VCTS mention is placed.
Believe the better forcing arrives late afternoon/early evening
where storms develop in central KS and track east through the
evening. Confidence in timing or duration is too uncertain to
mention at this time. Gusty south winds prevail throughout period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Omitt
AVIATION...Bowen
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1202 AM CDT SAT MAY 16 2015
...UPDATE TO AVIATION...
.SYNOPSIS...
ISSUED AT 1102 PM CDT FRI MAY 15 2015
WV IMAGERY AND 00Z UPPER AIR ANALYSIS INDICATE A BROAD UPPER LEVEL
TROUGH OF LOW PRESSURE PUSHING SLOWLY EAST ACROSS THE GREAT BASIN
REGION. MEANWHILE, AN H5 VORT MAXIMA IS CYCLING EASTWARD ACROSS
THE DESERT SOUTHWEST WITHIN THE BROADER SCALE TROUGH. NEAR THE
SURFACE, AN AREA OF LOW PRESSURE IS POSITIONED ACROSS NORTHEASTERN
COLORADO WITH AN ATTENDANT TROUGH AXIS EXTENDING SOUTHWARD ALONG
THE KANSAS AND COLORADO BORDER.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 141 PM CDT FRI MAY 15 2015
RAP AND NGM BOTH SUPPORTING A SURFACE BOUNDARY EXTENDING FROM
NEAR HAYS TO COLDWATER AT 00Z SATURDAY WITH WEAK 0-1KM MOISTURE
CONVERGENCE OCCURRING ALONG THIS BOUNDARY. 0-6KM SHEAR IN THIS
AREA WILL BE FROM 20 TO 25 KNOTS AND CAPE VALUES ARE EXPECTED TO
RANGE FROM 1000 TO 1500 J/KG. RAP HAS SOME CIN REMAINING IN THIS
AREA GIVEN THE WARM MID LEVEL TEMPERATURES WHILE THE NAM SUGGESTS
A FEW ISOLATED THUNDERSTORMS BEING POSSIBLE. AT THIS TIME GIVEN
THE CU DEVELOPING WILL RETAIN MENTION OF ISOLATED THUNDERSTORMS
GOING ALONG AND EAST OF THIS BOUNDARY EARLY TONIGHT. ANOTHER AREA
OF THUNDERSTORMS WILL DEVELOP EARLY THIS EVENING NEAR THE COLORADO
BORDER. THIS AREA WILL HAVE MORE FAVORABLE UPPER LEVEL DYNAMICS
ALONG WITH IMPROVING WARM AIR ADVECTION NEAR THE NOSE OF A 50 KNOT
850MB JET BASED ON THE 12Z NAM. THESE STORMS WILL MARCH EAST
ACROSS WESTERN KANSAS OVERNIGHT WITH A FEW OF THESE STORMS BEING
CAPABLE OF PRODUCING SMALL HAIL AND WIND GUSTS OF UP TO 55 MPH.
BY EARLY SATURDAY MORNING THIS THUNDERSTORM ACTIVITY WILL BE MOVE
INTO CENTRAL KANSAS AS AN UPPER LEVEL TROUGH CROSSES EASTERN
COLORADO AND NORTHEAST NEW MEXICO. 12Z NAM SHOWING 0-6KM SHEAR
SATURDAY AFTERNOON RANGING FROM 40 TO NEAR 50 KNOTS AND CAPE
VALUES WILL RANGING FROM 1500 TO 2500 J/KG AHEAD OF THIS
UPPER LEVEL SYSTEM. THIS CONTINUES TO SUPPORT THE CHANCE FOR
SEVERE THUNDERSTORMS ALONG AND EAST OF WHERE THIS DRY LINE WILL BE
LOCATED BETWEEN 18Z AND 21Z SATURDAY. LARGE HAIL AND STRONG
DAMAGING WINDS CURRENTLY APPEARS TO BE THE MAIN HAZARD ALONG WITH
PERIODS OF HEAVY RAINFALL. A FEW TORNADOES WILL ALSO BE POSSIBLE
LATE SATURDAY AND EARLY SATURDAY NIGHT.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 141 PM CDT FRI MAY 15 2015
EVENING CONVECTION WILL TAPER OFF EARLY SATURDAY NIGHT AS THE
UPPER LEVEL TROUGH LIFTS NORTHEAST INTO NORTH CENTRAL KANSAS AND
THE DRY LINE/COLD FRONT MOVES SOUTH AND EAST. WESTERLY DOWNSLOPE
FLOW WILL DEVELOP BY EARLY SUNDAY MORNING AND CONTINUE THROUGH THE
REMAINDER OF THE WEEKEND AS ANOTHER UPPER LEVEL TROUGH MOVES OUT
OF SOUTHERN WYOMING AND INTO THE CENTRAL HIGH PLAINS. 700MB TO
500MB LAPSE RATES WILL VARY FROM 7 TO 8C/KM AHEAD OF THIS UPPER
WAVE, HOWEVER MOISTURE APPEARS SOMEWHAT LIMITED EARLY SUNDAY
NIGHT. ALTHOUGH A FEW SPRINKLE MAY BE POSSIBLE NEAR AND NORTH OF
THE INTERSTATE 70 CORRIDOR, AT THIS TIME WILL ONLY INCREASE CLOUD
COVER AT THIS TIME SUNDAY EVENING GIVEN THE LIMITED MOISTURE IN
THE LOWER LEVELS.
GIVEN THE WESTERLY DOWNSLOPE FLOW AND 850MB TEMPERATURES AT 00Z
MONDAY WILL RANGING FROM 18C TO NEAR 24C THE PREVIOUS FORECAST
STILL LOOKS ON TRACK WITH HIGHS RANGING FROM THE UPPER 70S IN WEST
CENTRAL KANSAS TO THE LOWER 80S IN SOUTH CENTRAL KANSAS.
EARLY NEXT WEEK AN UPPER LEVEL RIDGE AXIS WILL CROSS WESTERN
KANSAS AS AN AREA OF HIGH PRESSURE AT THE SURFACE BUILDS INTO
KANSAS PLAINS. TEMPERATURES ON MONDAY WILL AVERAGE AROUND 10F
COOLER WHEN COMPARED TO THE HIGHS ON SUNDAY GIVEN THE 900 TO
850MB TEMPERATURE TRENDS FROM 00Z MONDAY AND 00Z TUESDAY.
CLOUDS WILL BE ON THE INCREASE MONDAY NIGHT AS AN UPPER LEVEL
TROUGH/LOW MOVES EAST ACROSS THE SOUTHWEST UNITED STATES. IN
ADDITION TO THE INCREASING CLOUDS THERE WILL ALSO BE A CHANCE FOR
PRECIPITATION TO DEVELOP BY EARLY TUESDAY GIVEN A MOIST
SOUTHEASTERLY UPSLOPE FLOW, WARM AIR ADVECTION, AND IMPROVING
ISENTROPIC LIFT ACROSS SOUTHWEST KANSAS. HIGH PRECIPITATION
CHANCES WILL CONTINUE THROUGH MID WEEK AS THE UPPER LEVEL SYSTEM
WEAKENS AND MOVES EAST NORTHEAST INTO THE CENTRAL PLAINS.
TEMPERATURES THROUGH MID WEEK WILL STAY ON THE COOL SIDE GIVEN THE
CLOUD COVER AND HIGH PRECIPITATION CHANCES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1200 AM CDT SAT MAY 16 2015
SHOWERS AND ISOLATED THUNDERSTORMS WILL SPREAD NORTHEAST ACROSS
SOUTHWEST AND CENTRAL KANSAS OVERNIGHT POTENTIALLY AFFECTING ALL TAF
SITES. OTHERWISE, VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES
THROUGH EARLY SATURDAY AFTERNOON. SCATTERED THUNDERSTORMS WILL BE
POSSIBLE AGAIN LATE SATURDAY AFTERNOON, GENERALLY IN THE VICINITY
OF KGCK AND TO THE EAST. A SURFACE LOW WILL REMAIN ANCHORED ACROSS
NORTHEASTERN COLORADO OVERNIGHT WITH AN ATTENDANT TROUGH AXIS
EXTENDING SOUTHWARD NEAR AND ALONG THE COLORADO BORDER. THIS WILL
RESULT IN SOUTHERLY WINDS OF 10 TO 20KT PERSISTING ACROSS WESTERN
KANSAS THROUGH LATE SATURDAY MORNING. THE SURFACE LOW IS THEN
EXPECTED TO DEEPEN ACROSS NORTHEASTERN COLORADO SATURDAY AFTERNOON
INCREASING WINDS UP TO AROUND 25 TO 35KT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 53 82 50 69 / 40 0 0 10
GCK 51 79 47 69 / 20 0 0 0
EHA 49 79 47 69 / 10 0 0 0
LBL 51 81 50 71 / 20 0 0 0
HYS 54 79 50 67 / 60 0 0 0
P28 58 83 54 72 / 50 0 0 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJOHNSON
SHORT TERM...BURGERT
LONG TERM...BURGERT
AVIATION...JJOHNSON
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1030 PM EDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 1030 PM EDT SUN MAY 17 2015
THE EARLIER CLUSTER OF STORMS FELL APART AS THEY ENCOUNTERED CELLS
RUNNING OUT AHEAD OF THEIR LINE AND IN THE FACE OF A WEAKENING
COLD POOL. ACCORDINGLY...HAVE UPDATED THE FORECAST TO LOWER POPS
THROUGH THE REST OF THE NIGHT AND FINE TUNE SKY COVER. ALSO
ADJUSTED THE T AND TD GRIDS TO REFLECT THE LATEST SHORTBLEND
GUIDANCE...OBS...AND TRENDS. THESE UPDATED GRIDS HAVE BEEN SENT
TO THE NDFD AND WEB SERVERS. FRESHENED ZONES HAVE ALSO BEEN
ISSUED.
UPDATE ISSUED AT 730 PM EDT SUN MAY 17 2015
23Z SFC ANALYSIS SHOWS A FAIRLY TIGHT GRADIENT OVER THE AREA
BETWEEN HIGH PRESSURE TO THE SOUTHEAST AND BROAD LOW PRESSURE TO
THE NORTHWEST. THE DIURNAL CYCLE BROUGHT ANOTHER ROUND OF SHOWERS
AND THUNDERSTORMS TO EAST KENTUCKY THAT HAVE NOW WANED. HOWEVER...
AN ARC OF MORE ORGANIZED STORMS IS NOW MOVING EAST THROUGH CENTRAL
KENTUCKY. THIS AREA HAS DEVELOPED A COLD POOL AND THIS SHOULD
HELP IT HOLD TOGETHER AS IT APPROACHES THE SOUTHWEST PARTS OF THE
CWA OVER THE NEXT COUPLE OF HOURS. A FEW STORMS HAVE POPPED UP
AHEAD OF THESE AND MAY HELP TO BREAK UP THE LINE OR LOCALLY
ENHANCE IT. THE NEAR TERM MODELS HAVE NOT CAPTURED THIS MESOSCALE
FEATURE WELL AND FOR THE MOST PART DAMPEN IT OUT FAR TOO QUICK.
FOR OUR FORECAST...HAVE BEEFED UP POPS ALONG THIS LINE OF
STORMS...AND THE COLD POOL SHOWERS BEHIND IT...AS IT TRACKS
THROUGH THE CWA BETWEEN NOW AND 04Z. THIS ENTAILED HIGHER QPF AS
WELL AS GUSTIER WINDS AMID THE PASSAGE. LATER AS THE CLOUDS START
TO BREAK UP IN THE WAKE OF THE STORMS AND STRATIFORM RAIN...EXPECT
PATCHY FOG TO DEVELOP AND LINGER THROUGH DAWN...MAINLY IN THE
VALLEYS. THE WHOLE FORECAST HAS BEEN UPDATED FOR THE NIGHT ALSO
INCORPORATING THE LATEST SHORTBLEND GUIDANCE...OBS...AND TRENDS.
THESE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
ADDITIONALLY...A NEW SET OF ZONES IS FORTHCOMING.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EDT SUN MAY 17 2015
THE HRRR MODEL HAS HAD THE BEST HANDLE ON THIS AFTERNOONS SHOWER
AND STORM ACTIVITY...WITH THE BULK OF CURRENT ACTIVITY OCCURRING
IN OUR FAR WESTERN COUNTIES. THE NAM12 HAS BEEN KEEPING CONVECTIVE
ACTIVITY MOST EXTENSIVE ACROSS OUR FAR EASTERN COUNTIES...WHICH IS
THE OPPOSITE OF WHAT IS ACTUALLY HAPPENING. THEREFORE...THE HRRR
SOLUTION WAS USED TO COMPOSE THE FIRST 12 HOURS OF THE SHORT TERM
FORECAST...AFTER 12Z...THE CONSALL SOLUTION WAS USED FOR THE
FORECAST. MORE SHOWERS AND STORMS WILL CONTINUE TO FORM WEST AND
SOUTHWEST OF THE AREA THROUGH THIS EVENING...AND THIS ACTIVITY
WILL SLOWLY MOVE WESTWARD INTO AND ACROSS EASTERN KENTUCKY THROUGH
0Z OR SO. AFTER THAT...ONCE THE SUN IS DOWN AND LOSS OF HEATING
OCCURS...THE SHOWERS AND STORMS WILL DROP OFF IN COVERAGE PRETTY
QUICKLY. AFTER HIGH RAIN CHANCES THIS AFTERNOON AND EVENING...THE
OVERNIGHT HOURS ARE FORECAST TO SEE ONLY ISOLATED SHOWERS AND
STORMS. SHOWERS AND STORMS WILL BE ON THE INCREASE AGAIN ON
MONDAY...BEGINNING IN THE LATE MORNING HOURS...AS A COLD FRONT
SLOWLY APPROACHES FROM THE WEST. THE PEAK OF ACTIVITY LOOKS TO BE
DURING THE AFTERNOON AND EVENING HOURS ONCE AGAIN...DURING PEAK
HEATING AND FRONTAL PASSAGE. SOME OF THE STRONGER STORMS COULD
PRODUCE LOCALLY HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING.
TEMPERATURES DURING THE SHORT TERM ARE STILL ON TRACK TO RUN WELL
ABOVE NORMAL FOR THIS TIME OF YEAR...REMAINING IN STEP WITH
CURRENT TRENDS AND A PERSISTENT SOUTHERLY FLOW PATTERN THAT HAS
BEEN CONSISTENTLY PUMPING WARM MOIST AIR OFF THE GULF OF MEXICO
INTO THE REGION. HIGHS ON MONDAY ARE STILL EXPECTED TO TOP OUT IN
THE LOWER 80S ACROSS THE AREA...WITH OVERNIGHT LOWS TONIGHT AND
TOMORROW NIGHT ONLY FALLING INTO THE LOW TO MID 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 300 PM EDT SUN MAY 17 2015
MODELS APPEAR TO BE IN GOOD AGREEMENT WITH THE MID AND UPPER LEVEL
PATTERN OVER OUR REGION...BUT DIFFER MORE ON DETAILS OF SENSIBLE
WEATHER WITH A SHORTWAVE DISTURBANCE LATE WEDNESDAY OR WEDNESDAY
NIGHT INTO EARLY THURSDAY.
IN GENERAL ZONAL FLOW WILL DOMINATE THE PATTERN UNTIL THE LAST 48
HOURS OF THE EXTENDED WHERE SHORT WAVE RIDGING WILL BUILD INTO AND
ACROSS THE OHIO VALLEY IN RESPONSE TO EASTWARD MOVEMENT OF WEST
COAST CUT OFF LOW. AT THE SURFACE A COOL CANADIAN AIR MASS...HIGH
PRESSURE SYSTEM WILL SETTLE DOWN INTO THE HEART OF THE CONUS BEHIND
AN EXITING COLD FRONT...NOSING ITS WAY INTO THE OHIO VALLEY. AS A
RESULT WE CAN EXPECT DRY...PLEASANTLY COOL WEATHER FOR THE START OF
THE EXTENDED. ALOFT...THE AFOREMENTIONED DISTURBANCE WILL ROUND A
DEEP HUDSON BAY LOW WEDNESDAY NIGHT. WE APPEAR TO RECEIVE A GLANCING
BLOW FROM THIS FEATURE AS IT TRACKS THROUGH THE GREAT LAKES REGION.
A SECOND LESS IMPRESSIVE DISTURBANCE BRUSHES THE OHIO VALLEY BY LATE
IN THE WEEK...DY6 FRI.
THE MAIN FORECAST CHALLENGE IN THE EXTENDED WILL BE THE SHORT WAVE
DISTURBANCE MOVING THROUGH THE AREA WEDNESDAY NIGHT INTO EARLY
THURSDAY. THE 0Z AND 12Z ECMWF PRODUCE CONSIDERABLY MORE SENSIBLE
WEATHER WITH THIS FEATURE THAN EITHER THE 0Z OR 12Z GFS. NOT SEEING
MUCH IN THE WAY OF TRENDS TO HELP WITH PREFERENCE OF SOLUTIONS.
THEREFORE RELIED STRONGLY ON MODEL BLENDS CONSIDERING THE MURKY
DETAILS WITH SENSIBLE WEATHER. INCREASING HEIGHTS THROUGH THE END OF
THE EXTENDED WILL MEAN A GRADUAL RISE IN TEMPS...INTO THE 80S BY THE
END OF THE FORECAST WINDOW.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 800 PM EDT SUN MAY 17 2015
THE MAIN CONCERN WITH THIS UPDATE TO THE TAFS REVOLVE AROUND THE
DOWNSTREAM IMPACTS OF THE INBOUND ARC OF STORMS AND TRAILING RAINS
HEADED FOR THE JKL CWA. HAVE TIMED THIS THROUGH THE TAF SITES WITH
IFR AND MVFR VIS/CIGS ALONG WITH GUSTY WINDS AS IT PASSES...
DIMINISHING WITH TIME AND DISTANCE WHILE PROGRESSING EAST.
FOLLOWING THE BAND OF STORMS/RAINS...PATCHY FOG WILL BE THE NEXT
CONCERN AND HAVE INCLUDED AT LEAST SOME MVFR VIS AT THE SITES
THROUGH 13Z. FOR MONDAY...ANTICIPATE A SIMILAR DAY WITH
CONVECTION DEVELOPING FROM THE HEATING MAKING STORMS POSSIBLE IN
THE AFTERNOON. OUTSIDE OF ANY STORMS...THE WINDS WILL BE LIGHT
FROM THE SOUTH TO SOUTHWEST TONIGHT BEFORE PICKING UP AT 5 TO 10
KTS BY MIDDAY MONDAY...ALONG WITH SOME GUSTS TO 15 KTS POSSIBLE IN
THE AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...AR
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
800 PM EDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 730 PM EDT SUN MAY 17 2015
23Z SFC ANALYSIS SHOWS A FAIRLY TIGHT GRADIENT OVER THE AREA
BETWEEN HIGH PRESSURE TO THE SOUTHEAST AND BROAD LOW PRESSURE TO
THE NORTHWEST. THE DIURNAL CYCLE BROUGHT ANOTHER ROUND OF SHOWERS
AND THUNDERSTORMS TO EAST KENTUCKY THAT HAVE NOW WANED. HOWEVER...
AN ARC OF MORE ORGANIZED STORMS IS NOW MOVING EAST THROUGH CENTRAL
KENTUCKY. THIS AREA HAS DEVELOPED A COLD POOL AND THIS SHOULD
HELP IT HOLD TOGETHER AS IT APPROACHES THE SOUTHWEST PARTS OF THE
CWA OVER THE NEXT COUPLE OF HOURS. A FEW STORMS HAVE POPPED UP
AHEAD OF THESE AND MAY HELP TO BREAK UP THE LINE OR LOCALLY
ENHANCE IT. THE NEAR TERM MODELS HAVE NOT CAPTURED THIS MESOSCALE
FEATURE WELL AND FOR THE MOST PART DAMPEN IT OUT FAR TOO QUICK.
FOR OUR FORECAST...HAVE BEEFED UP POPS ALONG THIS LINE OF
STORMS...AND THE COLD POOL SHOWERS BEHIND IT...AS IT TRACKS
THROUGH THE CWA BETWEEN NOW AND 04Z. THIS ENTAILED HIGHER QPF AS
WELL AS GUSTIER WINDS AMID THE PASSAGE. LATER AS THE CLOUDS START
TO BREAK UP IN THE WAKE OF THE STORMS AND STRATIFORM RAIN...EXPECT
PATCHY FOG TO DEVELOP AND LINGER THROUGH DAWN...MAINLY IN THE
VALLEYS. THE WHOLE FORECAST HAS BEEN UPDATED FOR THE NIGHT ALSO
INCORPORATING THE LATEST SHORTBLEND GUIDANCE...OBS...AND TRENDS.
THESE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
ADDITIONALLY...A NEW SET OF ZONES IS FORTHCOMING.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EDT SUN MAY 17 2015
THE HRRR MODEL HAS HAD THE BEST HANDLE ON THIS AFTERNOONS SHOWER
AND STORM ACTIVITY...WITH THE BULK OF CURRENT ACTIVITY OCCURRING
IN OUR FAR WESTERN COUNTIES. THE NAM12 HAS BEEN KEEPING CONVECTIVE
ACTIVITY MOST EXTENSIVE ACROSS OUR FAR EASTERN COUNTIES...WHICH IS
THE OPPOSITE OF WHAT IS ACTUALLY HAPPENING. THEREFORE...THE HRRR
SOLUTION WAS USED TO COMPOSE THE FIRST 12 HOURS OF THE SHORT TERM
FORECAST...AFTER 12Z...THE CONSALL SOLUTION WAS USED FOR THE
FORECAST. MORE SHOWERS AND STORMS WILL CONTINUE TO FORM WEST AND
SOUTHWEST OF THE AREA THROUGH THIS EVENING...AND THIS ACTIVITY
WILL SLOWLY MOVE WESTWARD INTO AND ACROSS EASTERN KENTUCKY THROUGH
0Z OR SO. AFTER THAT...ONCE THE SUN IS DOWN AND LOSS OF HEATING
OCCURS...THE SHOWERS AND STORMS WILL DROP OFF IN COVERAGE PRETTY
QUICKLY. AFTER HIGH RAIN CHANCES THIS AFTERNOON AND EVENING...THE
OVERNIGHT HOURS ARE FORECAST TO SEE ONLY ISOLATED SHOWERS AND
STORMS. SHOWERS AND STORMS WILL BE ON THE INCREASE AGAIN ON
MONDAY...BEGINNING IN THE LATE MORNING HOURS...AS A COLD FRONT
SLOWLY APPROACHES FROM THE WEST. THE PEAK OF ACTIVITY LOOKS TO BE
DURING THE AFTERNOON AND EVENING HOURS ONCE AGAIN...DURING PEAK
HEATING AND FRONTAL PASSAGE. SOME OF THE STRONGER STORMS COULD
PRODUCE LOCALLY HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING.
TEMPERATURES DURING THE SHORT TERM ARE STILL ON TRACK TO RUN WELL
ABOVE NORMAL FOR THIS TIME OF YEAR...REMAINING IN STEP WITH
CURRENT TRENDS AND A PERSISTENT SOUTHERLY FLOW PATTERN THAT HAS
BEEN CONSISTENTLY PUMPING WARM MOIST AIR OFF THE GULF OF MEXICO
INTO THE REGION. HIGHS ON MONDAY ARE STILL EXPECTED TO TOP OUT IN
THE LOWER 80S ACROSS THE AREA...WITH OVERNIGHT LOWS TONIGHT AND
TOMORROW NIGHT ONLY FALLING INTO THE LOW TO MID 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 300 PM EDT SUN MAY 17 2015
MODELS APPEAR TO BE IN GOOD AGREEMENT WITH THE MID AND UPPER LEVEL
PATTERN OVER OUR REGION...BUT DIFFER MORE ON DETAILS OF SENSIBLE
WEATHER WITH A SHORTWAVE DISTURBANCE LATE WEDNESDAY OR WEDNESDAY
NIGHT INTO EARLY THURSDAY.
IN GENERAL ZONAL FLOW WILL DOMINATE THE PATTERN UNTIL THE LAST 48
HOURS OF THE EXTENDED WHERE SHORT WAVE RIDGING WILL BUILD INTO AND
ACROSS THE OHIO VALLEY IN RESPONSE TO EASTWARD MOVEMENT OF WEST
COAST CUT OFF LOW. AT THE SURFACE A COOL CANADIAN AIR MASS...HIGH
PRESSURE SYSTEM WILL SETTLE DOWN INTO THE HEART OF THE CONUS BEHIND
AN EXITING COLD FRONT...NOSING ITS WAY INTO THE OHIO VALLEY. AS A
RESULT WE CAN EXPECT DRY...PLEASANTLY COOL WEATHER FOR THE START OF
THE EXTENDED. ALOFT...THE AFOREMENTIONED DISTURBANCE WILL ROUND A
DEEP HUDSON BAY LOW WEDNESDAY NIGHT. WE APPEAR TO RECEIVE A GLANCING
BLOW FROM THIS FEATURE AS IT TRACKS THROUGH THE GREAT LAKES REGION.
A SECOND LESS IMPRESSIVE DISTURBANCE BRUSHES THE OHIO VALLEY BY LATE
IN THE WEEK...DY6 FRI.
THE MAIN FORECAST CHALLENGE IN THE EXTENDED WILL BE THE SHORT WAVE
DISTURBANCE MOVING THROUGH THE AREA WEDNESDAY NIGHT INTO EARLY
THURSDAY. THE 0Z AND 12Z ECMWF PRODUCE CONSIDERABLY MORE SENSIBLE
WEATHER WITH THIS FEATURE THAN EITHER THE 0Z OR 12Z GFS. NOT SEEING
MUCH IN THE WAY OF TRENDS TO HELP WITH PREFERENCE OF SOLUTIONS.
THEREFORE RELIED STRONGLY ON MODEL BLENDS CONSIDERING THE MURKY
DETAILS WITH SENSIBLE WEATHER. INCREASING HEIGHTS THROUGH THE END OF
THE EXTENDED WILL MEAN A GRADUAL RISE IN TEMPS...INTO THE 80S BY THE
END OF THE FORECAST WINDOW.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 800 PM EDT SUN MAY 17 2015
THE MAIN CONCERN WITH THIS UPDATE TO THE TAFS REVOLVE AROUND THE
DOWNSTREAM IMPACTS OF THE INBOUND ARC OF STORMS AND TRAILING RAINS
HEADED FOR THE JKL CWA. HAVE TIMED THIS THROUGH THE TAF SITES WITH
IFR AND MVFR VIS/CIGS ALONG WITH GUSTY WINDS AS IT PASSES...
DIMINISHING WITH TIME AND DISTANCE WHILE PROGRESSING EAST.
FOLLOWING THE BAND OF STORMS/RAINS...PATCHY FOG WILL BE THE NEXT
CONCERN AND HAVE INCLUDED AT LEAST SOME MVFR VIS AT THE SITES
THROUGH 13Z. FOR MONDAY...ANTICIPATE A SIMILAR DAY WITH
CONVECTION DEVELOPING FROM THE HEATING MAKING STORMS POSSIBLE IN
THE AFTERNOON. OUTSIDE OF ANY STORMS...THE WINDS WILL BE LIGHT
FROM THE SOUTH TO SOUTHWEST TONIGHT BEFORE PICKING UP AT 5 TO 10
KTS BY MIDDAY MONDAY...ALONG WITH SOME GUSTS TO 15 KTS POSSIBLE IN
THE AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...AR
LONG TERM...AR
AVIATION...GREIF
AREA FORECAST DISCUSSION
NWS PADUCAH KY
208 PM CDT SAT MAY 16 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 208 PM CDT SAT MAY 16 2015
LOCALLY HEAVY RAIN IN PARTS OF WEST KY WITH AMOUNTS SINCE MIDNIGHT
1-2" IN A FEW SPOTS...MOSTLY AT OR BELOW 1". AREAL FLOOD
ADVISORIES WILL SUFFICE GIVEN THE PROGRESSIVE NATURE OF THE
ACTIVITY AND THE DOWNWARD TREND EXPECTED OVERALL. LITTLE TO NO
LIGHTNING...DEFINITELY EFFICIENT NONE THE LESS GIVEN WEAK LAPSE
RATES AND SMALL CAPE. ALL THE MODELS POINT TO A DIMINISHING TREND
FOR THE OVERNIGHT IN THE WAKE OF THIS WAVE THAT WE HAVE MONITORED
ON WVAPOR MOVING SLOWLY NE. THE RAP AND NAM WERE GENERALLY
FOLLOWED. WE CONTINUE TO HOLD TEMPS DOWN THE REST OF TODAY AS
WELL. THEY SHOULD FALL LITTLE TONIGHT WITH THE STAGNANT/HUMID
AIRMASS IN PLACE AND SOUTHERLY FLOW THE RULE.
SPC EXPANDED THEIR SLIGHT RISK AREA EAST DAY 2 INTO 1/2 OF THE
AREA FROM THE WEST. THIS SEEMS OVERDONE AND TEND TO DISAGREE. SURE
THERE COULD BE A FEW WARNINGS. BUT ENOUGH QUESTION MARKS EXIST.
THE NAM SUGGESTS A MIN CORRIDOR OF WEAK INSTABILITY ACROSS MUCH
OF THE AREA SUNDAY WITH CONVECTION AND CLOUDS ALREADY INTO THE
AREA AND BETTER DESTABILIZATION TO OUR WEST AND EAST. THE GFS AND
ECMWF SHOW BETTER DESTABILIZATION THROUGH THE DAY. EVEN IF WE
DESTABILIZE... BETTER WIND FIELDS ARE POSITIONED TO OUR WEST AND
NORTH AND NOT SUPPORTIVE OF SUSTAINED ORGANIZATION. WILL KEEP
POPS HIGH CHANCE GIVEN UNCERTAINTY WITH RESPECT TO COVERAGE.
SHOULD BE WARMER THAN TODAY.
SUNDAY NIGHT THROUGH MONDAY EVENING...WILL CONTINUE WITH HIGH
CHANCE TO LOW END LIKELY POPS FOR CONVECTION...AS THE FRONT VERY
SLOWLY WORKS SOUTH INTO THE AREA BY MONDAY EVENING/NIGHT. BEST
CHANCES WILL EVENTUALLY FOCUS ACROSS THE SOUTHEAST 1/2 TO 2/3 OF
THE AREA.
.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 208 PM CDT SAT MAY 16 2015
HIGHER THAN AVERAGE CONFIDENCE IN THE EXTENDED.
MODELS AND ENSEMBLES IN FAIR AGREEMENT WITH THE EXTENDED FORECAST.
SURFACE HIGH PRESSURE WILL BE THE MAIN SYNOPTIC SCALE FEATURE IN
CONTROL. HOWEVER THERE WILL BE A WEAK PERTURBATION IN THE NEARLY
ZONAL FLOW ALOFT WITH A REFLECTION OF A SURFACE LOW PASSING JUST TO
OUR SOUTH. THIS WILL BRING AT LEAST A CHANCE OF SHOWERS TO THE AREA
WEDNESDAY. SURFACE BASED CONVECTION LOOKS UNLIKELY WITH POSITIVE
LI`S AND LITTLE TO NO CAPE. ALTHOUGH SHOWALTERS IN VERY POSITIVE...K
INDEX VALUES ARE IN THE MID 20S. SO WILL NOT RULE OUT A CLAP OF
THUNDER BUT NOTHING IMPRESSIVE AT THIS TIME. OTHERWISE HIGH PRESSURE
WILL BE THE DOMINANT FEATURE AFTER THE PASSAGE OF THIS SURFACE LOW.
TEMPERATURES WILL BE AT SLIGHTLY BELOW NORMAL IN THE EXTENDED WITH
WINDS RELATIVELY LIGHT AFTER WEDNESDAY.
&&
.AVIATION...
ISSUED AT 208 PM CDT SAT MAY 16 2015
WILL MAINTAIN CONVECTIVE CHANCES THROUGH MID TO LATE AFTERNOON.
OVERNIGHT EXPECT A DOWNWARD TREND IN COVERAGE...SO NO INCLUSION
FOR THE OVERNIGHT INTO THE MORNING SUNDAY. LOW CONFIDENCE IN BASE
HEIGHTS OVERNIGHT. GENERALLY STAYED MVFR THROUGH VARIABILITY IS
NOT OUT OF THE QUESTION. SOUTH WINDS TO PERSIST...WITH GUSTS 15-20
KTS DEVELOPING SUNDAY MORNING.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1032 PM CDT SUN MAY 17 2015
.UPDATE...
TO MAKE ADJUSTMENTS TO THE RAIN CHANCES TONIGHT THROUGH MONDAY
NIGHT AND CONTINUED THE THREAT FOR FLASH FLOODING FOR EAST AND
NORTHEAST TEXAS...NORTHWEST AND NORTH CENTRAL LOUISIANA AND
ADJACENT SOUTHWEST AND SOUTH CENTRAL ARKANSAS AND SOUTHEAST
OKLAHOMA.
&&
.DISCUSSION...
A CONTINUED SOUTHERLY FLOW OF GULF MOISTURE TO GO ALONG WITH A
CONTRIBUTING SUPPLY OF PACIFIC MOISTURE AND A SERIES OF UPPER
LEVEL DISTURBANCES RIDING TOWARD THE FOUR STATE REGION WILL
CONTINUE TO PROVIDE SHOWERS AND THUNDERSTORMS OVERNIGHT. SOME OF
THE STORMS WILL DEVELOP AND SPREAD OVER THE SAME AREAS THAT HAVE
HAD LOCALLY HEAVY RAIN LATELY RESULTING IN FLASH FLOODING. /06/
&&
.PREV DISCUSSION... /ISSUED 630 PM CDT SUN MAY 17 2015/
AVIATION...
AREAL TERMINAL SITES ALL REPORTING VFR CONDITIONS AS CONVECTION
HAS SHIFTED TO THE EAST AND TO THE SOUTH OF THE REGION...WITH
MOSTLY MID AND UPPER LVL CIGS REMAINING. MCS DEVELOPMENT PROGGED
TO POSSIBLY MOVE INTO THE KTXK...KTYR...AND KGGG VCNTYS AFTER
18/04Z...AND BECOME MORE ORGANISED ACROSS THE LA TERMINALS AT KSHV
AND KMLU BTWN 18/06-08Z. HOWEVER...AIRMASS CURRENTLY WORKED OVER
SO TIMING OF REDEVELOPMENT IN QUESTION. SOME PATCHY FOG POSSIBLE
FROM WET GROUND AND LIGHT WINDS OVERNIGHT...ESPECIALLY WHERE UPPER
LVL CLOUDS THIN OUT. WINDS TO REMAIN WELL BELOW 10 KTS AREAWIDE
THRU PERIOD...AND MOSTLY SOUTHERLY./VII/.
PREV DISCUSSION... /ISSUED 455 PM CDT SUN MAY 17 2015/
DISCUSSION...
MOST OF THE REMNANTS OF THE MORNING MCS HAVE EXITED THE REGION AS
OF 2115Z...ALTHOUGH SCT CONVECTION HAS REDEVELOPED OVER SE TX/SW
LA AND HAVE BEGUN TO SPREAD NE INTO THE HIGHER INSTABILITY AIR
WHERE MLCAPES STILL RANGE FROM 2000-2500 J/KG. BELIEVE THAT MUCH
OF THIS CONVECTION WILL GRADUALLY DIMINISH BY EARLY/MID EVENING
WITH THE LOSS OF HEATING/STABILITY. HOWEVER...OUR FOCUS WILL TURN
TO THE W AS THE AFTERNOON WATER VAPOR IMAGERY DEPICTS A WELL-
DEFINED SHORTWAVE OVER ERN NM ENTERING FAR W TX...WHICH REMAINS
PROGGED TO LIFT NE ACROSS THE RED RIVER VALLEY LATE THIS
EVENING/OVERNIGHT. THE AIR MASS OVER E TX/SE OK/SW AR REMAINS
SOMEWHAT STABLE THIS AFTERNOON IN WAKE OF THE MORNING
MCS...ALTHOUGH SBCIN HAS WEAKENED OVER THIS AREA OVER THE LAST FEW
HOURS AS SOME HEATING HAS OCCURRED BENEATH THE DENSE CONVECTIVE
DEBRIS IN PLACE. THE SHORT TERM PROGS ARE IN GENERAL AGREEMENT
WITH SCT CONVECTION REDEVELOPING LATER THIS EVENING OVER THE
REGION...ATOP A STILL MOIST AND SOMEWHAT UNSTABLE AIRMASS WHERE
DIFFLUENT FLOW ALOFT SPREADS OVER THE REGION. COULD ALREADY BE
SEEING EVIDENCE OF THE FORCING ALOFT OVER SCNTRL/WCNTRL TX...WHERE
VISIBLE SATELLITE IMAGERY DEPICTS AN ELEVATED CU/AC FIELD
DEVELOPING OVER THESE AREAS. THE NAM/GFS ARE A LITTLE MORE
AGGRESSIVE IN DEVELOPING SCT CONVECTION BY MID TO LATE
EVENING...WITH THE HRRR A BIT SLOWER /AFTER 06Z/ OVER NE TX/SW
AR/POSSIBLY NW LA. HOWEVER...QPF PLACEMENTS VARY CONSIDERABLE WITH
THE MODELS THIS AFTERNOON...AND HAVE TAKEN A BLEND OF THE MODELS
AND ISSUED A FLASH FLOOD WATCH FROM 03Z THIS EVENING THROUGH 18Z
MONDAY FOR MUCH OF E TX/SE OK/SW AR/NW LA. THESE AREAS REMAIN
SATURATED FROM HEAVY RAINFALL THAT HAS FALLEN OVER THE LAST COUPLE
OF WEEKS...AND WILL BE FAIR GAME FOR CELL TRAINING LATER TONIGHT.
HAVE ADDED HEAVY RAINFALL TO THE FORECAST LATE TONIGHT THROUGH
MONDAY MORNING FOR THE WATCH AREA...AS PW/S CLIMB TO 1.8-2.0
INCHES...VERY NEAR THE MAX MOVING AVERAGE OF CLIMO FOR THE DATE.
AREAS TO THE SE OVER THE SRN SECTIONS OF NCNTRL LA HAVE NOT SEEN
NEARLY AS MUCH RAIN AS AREAS FARTHER N AND W...AND SHOULD BE ABLE
TO TAKE THE HEAVY RAIN AS IT MOVES THROUGH THE AREAS MONDAY. THE
HEAVY RAINFALL/FLASH FLOOD THREAT OVER THE WATCH AREAS SHOULD
DIMINISH BY EARLY MONDAY AFTERNOON AS THE SHORTWAVE QUICKLY
SPREADS ENE INTO THE MID-SOUTH/LOWER MS VALLEY.
THE CLOSED LOW A CPL HUNDRED MILES W OF THE CA COAST THIS
AFTERNOON IS EXPECTED TO COME ASHORE INTO CA EARLY MONDAY...WITH
THE MAIN ATTENDENT TROUGH LIFTING NE INTO THE SRN ROCKIES BY EARLY
TUESDAY AND INTO THE PLAINS TUESDAY AFTERNOON. THIS TROUGH WILL
HELP TO AMPLIFY SOMEWHAT FLAT UPPER RIDGING ALOFT OVER THE SRN
PLAINS/MID AND LOWER MS VALLEY AND SE STATES TUESDAY...WITH THE
FLAT RIDGING PERSISTING THROUGH MUCH OF THIS WEEK. THE SHORT TERM
PROGS REMAIN IN AGREEMENT WITH A WEAK SFC FRONT BACKDOORING SW
INTO ERN OK/CNTRL AR TUESDAY MORNING BEFORE BECOMING STATIONARY.
PREFER THE NAM/ECMWF POSITION OF THE FRONT THAN THE GFS...WHICH
SEEMS MUCH TOO FAR S GIVEN THE LACK OF HEIGHT FALLS ALOFT TO HELP
DRIVE THE FRONT FARTHER S. THE FRONT SHOULD HELP FOCUS SCT
CONVECTION DURING PEAK HEATING TUESDAY...WHILE OTHER ISOLATED TO
WIDELY SCT CONVECTION DEVELOPS FARTHER S WHERE
INSTABILITY/MOISTURE LIE OVER E TX/N LA...EVEN A WEAK
PERTURBATIONS SHIFT E ATOP THE FLAT RIDGE ALOFT. THE SFC FRONT
SHOULD LIFT BACK N TUESDAY NIGHT...BEFORE ANOTHER WEAK COOL FRONT
BEGINS TO BUILD S ACROSS OK/NW AR WEDNESDAY AFTERNOON. THE PROGS
ARE AGAIN KEYING IN WEAKNESSES IN THE FLOW ALOFT ATOP THE RIDGE TO
ENHANCE SCT CONVECTION DEVELOPMENT MAINLY OVER CNTRL/SRN OK/SW AR
WEDNESDAY AFTERNOON...BEFORE THE FRONT SLOWLY SLIDE INTO THE
REGION WEDNESDAY NIGHT/THURSDAY BEFORE BECOMING STATIONARY.
HAVE MAINTAINED LIKELY/HIGH CHANCE POPS WEDNESDAY NIGHT AHEAD OF
THE FRONT...WITH MID CHANCE POPS THURSDAY WITH THE FROPA. HAVING
THE SFC BNDRY AROUND THROUGH LATE FRIDAY WILL FOCUS SCT CONVECTION
DEVELOPMENT THROUGH LATE WEEK...BEFORE THE FRONT BEGINS TO LIFT
BACK N OUT OF THE AREA. TEMPS WILL REMAIN NEAR/SLIGHTLY ABOVE
CLIMO THROUGH MUCH OF THE PERIOD.
PRELIMS TO FOLLOW BELOW...
15
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 71 82 70 86 / 70 70 30 30
MLU 72 81 69 86 / 60 70 40 40
DEQ 68 83 67 82 / 50 40 40 30
TXK 70 83 68 83 / 60 50 40 30
ELD 70 81 68 84 / 70 70 40 30
TYR 71 82 69 85 / 60 50 30 30
GGG 70 82 69 86 / 70 60 30 30
LFK 72 82 71 88 / 40 70 30 40
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR ARZ050-051-
059>061-070>073.
LA...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR LAZ001>006-
010>012.
OK...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR OKZ077.
TX...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR TXZ096-097-
108>112-124>126-136>138-149>153.
&&
$$
06
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
630 PM CDT SUN MAY 17 2015
.AVIATION...
AREAL TERMINAL SITES ALL REPORTING VFR CONDITIONS AS CONVECTION
HAS SHIFTED TO THE EAST AND TO THE SOUTH OF THE REGION...WITH
MOSTLY MID AND UPPER LVL CIGS REMAINING. MCS DEVELOPMENT PROGGED
TO POSSIBLY MOVE INTO THE KTXK...KTYR...AND KGGG VCNTYS AFTER
18/04Z...AND BECOME MORE ORGANISED ACROSS THE LA TERMINALS AT KSHV
AND KMLU BTWN 18/06-08Z. HOWEVER...AIRMASS CURRENTLY WORKED OVER
SO TIMING OF REDEVELOPMENT IN QUESTION. SOME PATCHY FOG POSSIBLE
FROM WET GROUND AND LIGHT WINDS OVERNIGHT...ESPECIALLY WHERE UPPER
LVL CLOUDS THIN OUT. WINDS TO REMAIN WELL BELOW 10 KTS AREAWIDE
THRU PERIOD...AND MOSTLY SOUTHERLY./VII/.
&&
.PREV DISCUSSION... /ISSUED 455 PM CDT SUN MAY 17 2015/
DISCUSSION...
MOST OF THE REMNANTS OF THE MORNING MCS HAVE EXITED THE REGION AS
OF 2115Z...ALTHOUGH SCT CONVECTION HAS REDEVELOPED OVER SE TX/SW
LA AND HAVE BEGUN TO SPREAD NE INTO THE HIGHER INSTABILITY AIR
WHERE MLCAPES STILL RANGE FROM 2000-2500 J/KG. BELIEVE THAT MUCH
OF THIS CONVECTION WILL GRADUALLY DIMINISH BY EARLY/MID EVENING
WITH THE LOSS OF HEATING/STABILITY. HOWEVER...OUR FOCUS WILL TURN
TO THE W AS THE AFTERNOON WATER VAPOR IMAGERY DEPICTS A WELL-
DEFINED SHORTWAVE OVER ERN NM ENTERING FAR W TX...WHICH REMAINS
PROGGED TO LIFT NE ACROSS THE RED RIVER VALLEY LATE THIS
EVENING/OVERNIGHT. THE AIR MASS OVER E TX/SE OK/SW AR REMAINS
SOMEWHAT STABLE THIS AFTERNOON IN WAKE OF THE MORNING
MCS...ALTHOUGH SBCIN HAS WEAKENED OVER THIS AREA OVER THE LAST FEW
HOURS AS SOME HEATING HAS OCCURRED BENEATH THE DENSE CONVECTIVE
DEBRIS IN PLACE. THE SHORT TERM PROGS ARE IN GENERAL AGREEMENT
WITH SCT CONVECTION REDEVELOPING LATER THIS EVENING OVER THE
REGION...ATOP A STILL MOIST AND SOMEWHAT UNSTABLE AIRMASS WHERE
DIFFLUENT FLOW ALOFT SPREADS OVER THE REGION. COULD ALREADY BE
SEEING EVIDENCE OF THE FORCING ALOFT OVER SCNTRL/WCNTRL TX...WHERE
VISIBLE SATELLITE IMAGERY DEPICTS AN ELEVATED CU/AC FIELD
DEVELOPING OVER THESE AREAS. THE NAM/GFS ARE A LITTLE MORE
AGGRESSIVE IN DEVELOPING SCT CONVECTION BY MID TO LATE
EVENING...WITH THE HRRR A BIT SLOWER /AFTER 06Z/ OVER NE TX/SW
AR/POSSIBLY NW LA. HOWEVER...QPF PLACEMENTS VARY CONSIDERABLE WITH
THE MODELS THIS AFTERNOON...AND HAVE TAKEN A BLEND OF THE MODELS
AND ISSUED A FLASH FLOOD WATCH FROM 03Z THIS EVENING THROUGH 18Z
MONDAY FOR MUCH OF E TX/SE OK/SW AR/NW LA. THESE AREAS REMAIN
SATURATED FROM HEAVY RAINFALL THAT HAS FALLEN OVER THE LAST COUPLE
OF WEEKS...AND WILL BE FAIR GAME FOR CELL TRAINING LATER TONIGHT.
HAVE ADDED HEAVY RAINFALL TO THE FORECAST LATE TONIGHT THROUGH
MONDAY MORNING FOR THE WATCH AREA...AS PW/S CLIMB TO 1.8-2.0
INCHES...VERY NEAR THE MAX MOVING AVERAGE OF CLIMO FOR THE DATE.
AREAS TO THE SE OVER THE SRN SECTIONS OF NCNTRL LA HAVE NOT SEEN
NEARLY AS MUCH RAIN AS AREAS FARTHER N AND W...AND SHOULD BE ABLE
TO TAKE THE HEAVY RAIN AS IT MOVES THROUGH THE AREAS MONDAY. THE
HEAVY RAINFALL/FLASH FLOOD THREAT OVER THE WATCH AREAS SHOULD
DIMINISH BY EARLY MONDAY AFTERNOON AS THE SHORTWAVE QUICKLY
SPREADS ENE INTO THE MID-SOUTH/LOWER MS VALLEY.
THE CLOSED LOW A CPL HUNDRED MILES W OF THE CA COAST THIS
AFTERNOON IS EXPECTED TO COME ASHORE INTO CA EARLY MONDAY...WITH
THE MAIN ATTENDENT TROUGH LIFTING NE INTO THE SRN ROCKIES BY EARLY
TUESDAY AND INTO THE PLAINS TUESDAY AFTERNOON. THIS TROUGH WILL
HELP TO AMPLIFY SOMEWHAT FLAT UPPER RIDGING ALOFT OVER THE SRN
PLAINS/MID AND LOWER MS VALLEY AND SE STATES TUESDAY...WITH THE
FLAT RIDGING PERSISTING THROUGH MUCH OF THIS WEEK. THE SHORT TERM
PROGS REMAIN IN AGREEMENT WITH A WEAK SFC FRONT BACKDOORING SW
INTO ERN OK/CNTRL AR TUESDAY MORNING BEFORE BECOMING STATIONARY.
PREFER THE NAM/ECMWF POSITION OF THE FRONT THAN THE GFS...WHICH
SEEMS MUCH TOO FAR S GIVEN THE LACK OF HEIGHT FALLS ALOFT TO HELP
DRIVE THE FRONT FARTHER S. THE FRONT SHOULD HELP FOCUS SCT
CONVECTION DURING PEAK HEATING TUESDAY...WHILE OTHER ISOLATED TO
WIDELY SCT CONVECTION DEVELOPS FARTHER S WHERE
INSTABILITY/MOISTURE LIE OVER E TX/N LA...EVEN A WEAK
PERTURBATIONS SHIFT E ATOP THE FLAT RIDGE ALOFT. THE SFC FRONT
SHOULD LIFT BACK N TUESDAY NIGHT...BEFORE ANOTHER WEAK COOL FRONT
BEGINS TO BUILD S ACROSS OK/NW AR WEDNESDAY AFTERNOON. THE PROGS
ARE AGAIN KEYING IN WEAKNESSES IN THE FLOW ALOFT ATOP THE RIDGE TO
ENHANCE SCT CONVECTION DEVELOPMENT MAINLY OVER CNTRL/SRN OK/SW AR
WEDNESDAY AFTERNOON...BEFORE THE FRONT SLOWLY SLIDE INTO THE
REGION WEDNESDAY NIGHT/THURSDAY BEFORE BECOMING STATIONARY.
HAVE MAINTAINED LIKELY/HIGH CHANCE POPS WEDNESDAY NIGHT AHEAD OF
THE FRONT...WITH MID CHANCE POPS THURSDAY WITH THE FROPA. HAVING
THE SFC BNDRY AROUND THROUGH LATE FRIDAY WILL FOCUS SCT CONVECTION
DEVELOPMENT THROUGH LATE WEEK...BEFORE THE FRONT BEGINS TO LIFT
BACK N OUT OF THE AREA. TEMPS WILL REMAIN NEAR/SLIGHTLY ABOVE
CLIMO THROUGH MUCH OF THE PERIOD.
PRELIMS TO FOLLOW BELOW...
15
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 71 82 70 86 / 70 70 30 30
MLU 72 81 69 86 / 60 70 30 40
DEQ 68 83 67 82 / 60 40 30 30
TXK 70 83 68 83 / 70 50 30 30
ELD 70 81 68 84 / 70 70 30 30
TYR 71 82 69 85 / 60 50 20 30
GGG 70 82 69 86 / 70 60 20 30
LFK 72 82 71 88 / 40 70 20 40
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH MONDAY
AFTERNOON FOR ARZ050-051-059>061-070>073.
LA...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH MONDAY
AFTERNOON FOR LAZ001>006-010>012.
OK...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH MONDAY
AFTERNOON FOR OKZ077.
TX...FLASH FLOOD WATCH FROM 10 PM CDT THIS EVENING THROUGH MONDAY
AFTERNOON FOR TXZ096-097-108>112-124>126-136>138-149>153.
&&
$$
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
406 PM CDT SAT MAY 16 2015
SHORT TERM...NOT MUCH HAS CHANGED FROM 24 HOURS AGO. STILL IN QUITE
AN ACTIVE CONVECTIVE DAY WITH WIDESPREAD SHOWERS AND SCATTERED
THUNDERSTORMS IMPACTING THE CWA EXCEPT FOR AREAS SOUTH OF INTERSTATE
10. THINKING THAT SINCE THE ENVIRONMENT IS SO SIMILAR...ACTIVITY
MAINTAINABILITY WILL GO WELL INTO THE AFTERNOON AND EVENING HOURS
AGAIN. HRRR SHOWS STORMS GOING PAST MIDNIGHT EAST OF I-55. MAIN
THREAT WILL BE HEAVY RAIN AND POSSIBLE FLASH FLOODING AS SOME
TRAINING HAS BEEN OCCURRING. OTHERWISE...TYPICAL MARITIME ENVIORNMENT
IN PLACE POSES THE THREAT FOR WATERSPOUTS WHICH CAN ON OCCASION MOVE
ONSHORE.
SYNOPTICALLY SPEAKING...AN UPPER LEVEL TROUGH IS IN THE PROCESS OF
SWINGING ACROSS THE ROCKIES AND WILL REACH THE UPPER MISSISSIPPI
VALLEY BY LATE TOMORROW. THE WESTERN ATLANTIC AND EASTERN GULF OF
MEXICO WILL REMAIN UNDER AN UPPER RIDGE DURING THIS TIME. THE LOCAL
CWA BEING CAUGHT BETWEEN THESE 2 FEATURES WHICH WILL BE A FUNNEL
ZONE OF MOISTURE AND WEAK SHORTWAVES. DAYTIME POPS INTO TOMORROW
STILL AT ABOUT 50 PERCENT.
MEFFER
&&
.LONG TERM...A WEAK FRONTAL BOUNDARY WILL SAG INTO THE AREA GOING
INTO TUESDAY. A GENERAL WEAK SURFACE TROUGH WILL BE THE FOCUS FOR
ENHANCED CONVECTION THROUGH JUST ABOUT THE ENTIRE WEEK WITH AT LEAST
40 PERCENT FOR DAILY POPS. UPPER LEVEL RIDGE WILL TRY TO REASSERT
ITSELF OVER THE REGION LATE WEEK AND INTO THE WEEKEND WHICH WOULD
LOWER POPS AND INCREASE TEMPS. UPPER 80S TO NEAR 90 DEGREES COULD BE
COMING THEN.
MEFFER
&&
.AVIATION... SHOWERS AND THUNDERSTORMS WILL GENERALLY BE A POTENTIAL
IMPACT TO TERMINALS NORTH OF A KNEW TO KHUM LINE THROUGH THE NEXT
SEVERAL HOURS BEFORE STARTING TO WIND DOWN. IN ADDITION...STRONG
SOUTHEAST WINDS WILL RELAX QUITE A BIT ONCE THE SUN BEGINS TO SET.
VFR CONDITIONS EXPECTED ONCE THE CONVECTION WANES THIS EVENING. KGPT
AND KASD WILL BE THE LAST TO BE CONVECTION FREE AND THAT MAY NOT
HAPPEN UNTIL LATE TONIGHT.
MEFFER
&&
.MARINE...CURRENT WINDS OVER OFFSHORE WATERS ARE RIGHT AT OR JUST
ABOVE 15 KNOTS...SO REISSUING EXERCISE CAUTION THRU TONIGHT. CURRENT
SYNOPSIS SHOWS SURFACE RIDGE CENTERED JUST OFF THE CAROLINA COASTS
EXTENDS WELL INTO THE GULF OF MEXICO WHICH HAS ESTABLISHED ONSHORE
FLOW. THIS HIGH WILL SLOWLY WEAKEN AS IT SAGS SOUTH TOWARDS FLORIDA.
LOCAL WINDS WILL FOLLOW THIS WEAKENING TREND AS WELL...FALLING TO
LESS THAN 10 KNOTS ON TUESDAY. WEAK WIND FIELD WILL REMAIN IN PLACE
AS A COLD FRONT STALLS ALONG THE NORTHERN GULF COAST MID WEEK AND A
RAGGED SURFACE HIGH TRIES TO ESTABLISH ITSELF OVER THE GULF OF
MEXICO. COULD RETURN TO MORE CONSISTENT SOUTHEASTERLY WINDS NEXT
WEEKEND.
MEFFER
&&
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...NONE.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT
TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 71 85 71 85 / 40 50 20 60
BTR 73 87 73 87 / 40 50 20 60
ASD 74 85 73 86 / 40 40 20 50
MSY 75 86 75 86 / 40 40 20 50
GPT 75 84 75 84 / 50 40 20 30
PQL 73 84 73 84 / 50 40 10 40
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NEW ORLEANS LA
1145 PM CDT FRI MAY 15 2015
.MESOSCALE UPDATE...
AREAL FLOOD ADVISORIES WILL BE ALLOWED TO EXPIRE AS
ISSUED...MIDNIGHT FOR SOUTH SHORE POLYGON AND 115 AM FOR NORTH
SHORE POLYGON. CONVERGENT BOUNDARY SHOULD WEAKEN WHILE OUTFLOW
BECOMES A MORE DOMINANT PLAYER OVERNIGHT FOR PROPAGATION OF STORM
INTO THE MISSISSIPPI COASTAL COUNTIES OVERNIGHT. HRRR MODEL RUN
FAVORS THIS SOLUTION AND MAY WARRANT ADDITIONAL ISSUANCES OF FLOOD
ADVISORIES...POSSIBLE FLASH FLOOD WARNINGS SHOULD A CONVERGENCE
AXIS BECOME ESTABLISHED FOR ANY SIGNIFICANT DURATION TONIGHT AND
EARLY SATURDAY MORNING. 24/RR
.AVIATION...
ONLY TERMINALS CURRENTLY WITH CONVECTIVE IMPACTS ARE KMSY AND KASD
AND EXPECTING DIMINISHING COVERAGE NEXT 1-2 HOURS.
MEANWHILE...KGPT AND KPQL HAVE HAD MINIMAL INFLUENCES FROM AREAL
CONVECTION TODAY AND MAY BE PRONE TO NOCTURNAL DEVELOPMENTS
BETWEEN 06-11Z. MVFR CONDITIONS AT MOST LOCATIONS TONIGHT
IMPROVING TO LOW END VFR CIGS OUTSIDE CONVECTION SATURDAY. GUST
POTENTIAL SOULD BE AROUND 30 KT WITH THE INITIAL STRONGER STORMS
BETWEEN 16Z-18Z CAPABLE OF WET MICROBURST GUSTS 40-45 KT...AND
FAVORED IN WESTERN TAFS LIKE KBTR AND KMCB WHERE MOISTURE RECOVERY
WILL BE GREATEST. 24/RR
&&
.PREV DISCUSSION... /ISSUED 840 PM CDT FRI MAY 15 2015/
..SOUNDING DISCUSSION...
ATMOSPHERE IS JUICY TONIGHT WITH A PRECIPITABLE WATER /PW/ VALUE
OVER 2 STANDARD DEVIATIONS ABOVE NORMAL AT 2.14 INCHES. THIS
DESTROYS THE OLD RECORD PW VALUE FOR THIS DATE AND TIME OF 1.8
INCHES AS FOUND ON THE SPC PW CLIMATOLOGY PAGE. THE TROPICAL
MOISTURE IS BEING DRAWN INTO THE AREA ON SOUTHERLY WINDS AVERAGING
20 TO 25 KNOTS IN THE LOW AND MID-LEVELS. A PEAK WIND SPEED OF 52
KNOTS WAS FOUND AT 46200 FEET. THERE IS A FAIR AMOUNT OF
INSTABILITY IN THE ATMOSPHERE...WHICH MAY ALLOW SHOWERS AND
THUNDERSTORMS TO LAST UNTIL AROUND OR PERHAPS AN HOUR OR TWO AFTER
MIDNIGHT.
00Z BALLOON INFO: LAUNCH WAS DELAYED A BIT DUE TO LIGHTNING IN THE
AREA...BUT OTHERWISE A ROUTINE FLIGHT. THE BALLOON ASCENDED FOR 74
MINUTES WHILE TRAVELING 13 MILES DOWNRANGE BURSTING EAST OF
NICHOLSON AT A HEIGHT OF 15.1 MILES ABOVE THE GROUND.
ANSORGE
PREV DISCUSSION... /ISSUED 354 PM CDT FRI MAY 15 2015/
PREVIOUS LONG TERM...LITTLE CHANGE IN THE LONG TERM FORECAST
PATTERN WITH CHANCES OF SHOWERS AND THUNDERSTORMS EACH DAY THROUGH
THE WORK WEEK. BLENDED GUIDANCE WILL BE USED WITH MAINLY
CHANCE/SCATTERED RAINFALL CHANCES DURING THE DIURNALLY FAVORED TIME
PERIODS. ALSO LITTLE DAY TO DAY TEMPERATURE CHANGE WITH THE
EXCEPTION OF THOSE SITES SEEING CONVECTION EARLY IN THE DAY.
35
AVIATION... SHOWERS AND THUNDERSTORMS WILL GENERALLY BE A POTENTIAL
IMPACT TO TERMINALS THROUGH THE NEXT FEW HOURS BEFORE STARTING TO
WIND DOWN AFTER AROUND 02Z. SO WILL CARRY -RA AND TEMPO TSRA IN MOST
TAFS THRU THIS AFTN. OVERNIGHT CONDITIONS WILL RANGE FROM MVFR TO
IFR CEILINGS.
MEFFER
MARINE... HIGH PRESSURE OVER THE EAST COAST WILL MAINTAIN A
SOUTHEASTERLY FLOW THROUGH MONDAY. THE PRESSURE GRADIENT WILL KEEP
OFFSHORE WATERS RIGHT AT THE THRESHOLD FOR EXERCISE CAUTION. IT DOES
APPEAR IT WILL BE EXCEEDED TONIGHT...SO GOING IT HAVE THE SCS
HEADLINE IN GRIDS THEN. THE HIGH WILL MOVE INTO THE GULF EARLY NEXT
WEEK CAUSING WIND SPEEDS TO LOWER EVEN MORE WITH A LIGHT BREEZE OUT
OF THE WEST BY WED. EACH DAY WILL BRING A GOOD CHANCE OF SH/TS
THROUGH THE MIDDLE OF NEXT WEEK.
MEFFER
DSS CODE...GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...NONE.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT
TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 70 83 71 85 / 50 60 50 50
BTR 71 85 72 86 / 40 60 50 50
ASD 72 83 73 85 / 50 60 50 50
MSY 73 84 75 85 / 40 60 50 50
GPT 74 82 75 84 / 50 60 40 40
PQL 72 82 73 84 / 50 60 50 50
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1132 PM CDT FRI MAY 15 2015
.AVIATION...LOW LEVEL WIND FIELD WILL BE STRENGTHENING OVERNIGHT
ACROSS THE AREA BRINGING IN WIDESPREAD MVFR CLOUDINESS. ENHANCED
LIFT AHEAD OF AN APPROACHING MID/UPPER TROF WILL MAINTAIN A FEW
SHOWERS OVER ACADIANA. MAINTAINING VCSH THROUGH THE NIGHT AT ARA
AND LFT. PASSAGE OF AFOREMENTIONED TROF AND DRIER AIR IN ITS WAKE
WILL RESULT IN LESS CONVECTION SATURDAY THAN TODAY FOR THE AREA.
WILL KEEP VCSH FOR THE MORNING AT ALL TERMINALS AND VCTS THROUGH
THE AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 1017 PM CDT FRI MAY 15 2015/
DISCUSSION...
LIFT ASSOCIATED WITH A SHORTWAVE TROF LIFTING THROUGH EASTERN TX
ALONG WITH A DEEP MSTR POOL PER KLIX 00Z RAOB HELPING TO
SUSTAIN/GENERATE CONVECTION ACROSS SOUTH CENTRAL/SOUTHEAST LA AND
THE ADJACENT COASTAL WATERS. POP/WX/QPF GRIDS WERE ADJUSTED IN THE
SHORT TERM BASED PRIMARILY ON THE HRRR AND RADAR TRENDS...WITH A
NOD TO THE FORMER OVERNIGHT WHICH SHOWS ISOLATED TO PERHAPS
SCATTERED ACTIVITY CONTINUING EAST OF THE SABINE RIVER. MINOR
TWEAKS TO REMAINING GRIDS...WITH A SLIGHT INCREASE IN WIND/WIND
GUST GRIDS REQUIRING A SCEC HEADLINE OVER THE GULF WATERS.
13
PREV DISCUSSION... /ISSUED 650 PM CDT FRI MAY 15 2015/
AVIATION...ISOLATED SHOWERS AND THUNDERSTORMS CONTINUE OVER
CENTRAL LOUISIANA INTO ACADIANA. REMAINDER OF THE AREA IS CLEAR OF
ANY PRECIP. MUCH OF THIS ACTIVITY WILL BE DYING OFF IN THE NEXT
FEW HOURS WITH COOLING. WILL HOWEVER MAINTAIN VCSH THROUGH THE
NIGHT AT LFT AND ARA WITH ACTIVITY NOTED OFFSHORE FROM THESE
SITES. OTHERWISE...VFR ONGOING OVER THE AREA AT THIS TIME.
EXPECTING ANOTHER ROUND OF MVFR STRATOCU TO DEVELOP AS THE NIGHT
PROGRESSES. ISOLATED TO SCATTERED SHOWERS ARE EXPECTED TO RETURN
AREA-WIDE SATURDAY MORNING...TRANSITIONING TO TSRA FOR THE
AFTERNOON.
PREV DISCUSSION... /ISSUED 325 PM CDT FRI MAY 15 2015/
DISCUSSION...AN UPPER TROUGH REMAINS ACROSS THE WEST HALF OF THE
COUNTRY THIS AFTERNOON WITH MULTIPLE SHORT WAVES ROTATING AROUND THE
LARGER GYRE. ONE SHORT WAVE IS PUSHING THROUGH THE EAST HALF OF TX
WITH A LINE OF STORMS PUSH ACROSS THE CENTRAL TX COAST. FARTHER
EAST ACROSS DEEP SE TX AND LA WHERE THE HEATING OF THE DAY HAS
COMBINED WITH THE UPPER DIVERGENCE IN PLACE TO DEVELOP SCT TO
NUMEROUS SHOWERS AND STORMS AWAY FROM THE COAST. AS SUNSET
APPROACHES CONVECTION IS EXPECTED TO DECREASE INCLUDING THE
CENTRAL TX COAST QLCS, HOWEVER AREAS OF RAIN MAY MOVE INTO THE
WEST HALF OF THE CWA AS THE REMNANTS OF THE LINE OF STORMS DRAWS
CLOSER AND ADDITIONAL SCT STORMS MAY REDEVELOP LATER IN THE NIGHT
AS THE SHORT WAVE MOVES IN. A SIMILAR SITUATION IS EXPECTED FOR
SAT AND SUN AS CONVECTION WILL REDEVELOP EACH AFTERNOON AND
GRADUALLY DECREASE THROUGH THE LATE AFTERNOON AND EARLY EVENING.
A SLIGHT INCREASE IN COVERAGE IS EXPECTED MONDAY AND TUESDAY AS THE
LARGER WESTERN TROUGH AXIS MOVES ACROSS THE REGION.
FROM MID WEEK ON MORE TYPICAL EARLY SUMMER WEATHER IS EXPECTED
WITH ISOLATED TO WIDELY SCT AFTERNOON STORMS OCCUR UNDER WEAK
RIDGING.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 70 85 72 87 / 20 60 30 50
LCH 74 85 75 86 / 30 40 20 40
LFT 72 86 74 87 / 40 50 30 40
BPT 75 86 75 86 / 20 30 20 40
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT EXERCISE CAUTION UNTIL 6 AM CDT SATURDAY FOR GMZ450-
452-455-470-472-475.
&&
$$
AVIATION...23
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1140 PM EDT SUN MAY 17 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 326 PM EDT SUN MAY 17 2015
A STRONG STORM FOR THIS TIME OF YEAR WILL TRACK TOWARD WESTERN
LAKE SUPERIOR BY MONDAY MORNING AND THEN INTO CENTRAL ONTARIO BY
TUESDAY MORNING. THAT WILL CAUSE A STRONG COLD FRONT TO COME
THROUGH THIS AREA MONDAY AFTERNOON. SCATTERED SHOWER AND
THUNDERSTORMS ARE EXPECTED EARLY TONIGHT WELL AHEAD OF THE COLD
FRONT. THEN IT WILL TURN BREEZY AND MUCH COLDER MONDAY NIGHT AND
TUESDAY. HIGHS WILLS STRUGGLE TO MAKE 50 TUESDAY AND THERE COULD
BE A FROST AND FREEZING TEMPERATURES BY WEDNESDAY MORNING.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 326 PM EDT SUN MAY 17 2015
I CONTINUE TO BELIEVE THE RISK FOR STRONG TO SEVERE STORMS IS
RATHER LIMITED TONIGHT. THE BEST DYNAMICS ARE TO OUR WEST AND
NORTH...CLOSER TO THE SYSTEM OVER MINNESOTA AND WISCONSIN. THE
LATEST RUN OF THE RAP MODEL (18Z) CONTINUES TO SHOW THE LOW LEVEL
JET CORE TRACKING THROUGH WESTERN WISCONSIN THIS EVENING LEAVING
SOUTHWEST MICHIGAN IN THE SPEED AREA BEHIND THAT JET. ALSO THE
BEST UPPER DIVERGENCE ASSOCIATED WITH THE POLAR JET CORE IS
EASILY OVER WISCONSIN. WHILE THERE IS A SIGNIFICANT AMOUNT OF
MIXED LAYER CAPE THIS EVENING THE LACK OF DYNAMICS WILL RESULT IN
THE BEST STORMS STAYING OVER WISCONSIN. EVEN SO SOME SHOWERS AND
THUNDERSTORMS WILL TRACK THROUGH OUR EASTERN CWA LATE THIS
AFTERNOON THEN ANOTHER AREA WILL TRACK THROUGH OUR CENTRAL AND
EASTER COUNTIES AFTER 8PM BUT I DO NOT EXPECT ANY SEVERE STORMS AT
THIS TIME.
DRY AIR MOVES IN MONDAY THEN MUCH COLDER AIR MOVES IN BEHIND THE
SYSTEM FOR MONDAY NIGHT INTO TUESDAY NIGHT. THERE IS NOT ENOUGH
MOISTURE FOR SHOWERS IN THE COLD AIR MONDAY NIGHT OR TUESDAY. WE
MAY WILL HAVE FREEZING TEMPERATURES AND WIDESPREAD FROST TUESDAY
NIGHT AS SKIES CLEAR.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 326 PM EDT SUN MAY 17 2015
MUCH OF THE EXTENDED PERIOD WILL BE COOL AND DRY...BUT WE SHOULD SEE
A WARM UP BY THE WEEKEND...ALONG WITH A CHANCE OF SHOWERS AND STORMS
RETURNING SATURDAY NIGHT AND SUNDAY.
AN UPPER LOW OVER JAMES BAY WILL KEEP US COOL WITH A NORTHWEST UPPER
FLOW. H8 TEMPS WED THROUGH FRI REMAIN IN THE +1 TO +4C RANGE...
KEEPING DAYTIME HIGH TEMPS BELOW NORMAL...MAINLY IN THE LOW AND MID
60S. THERE SHOULD BE A BACK DOOR COLD FRONT COME THROUGH THURSDAY
NIGHT...BUT IT APPEARS DRY...JUST SUPPLYING A EXTRA SHOT OF COOL AIR
INTO FRIDAY.
A WARM UP SHOULD COMMENCE SATURDAY AS AN UPPER RIDGE BEGINS TO
BUBBLE TOWARD THE AREA PUSHING THE NW FLOW EAST. TEMPS SHOULD
RETURN TO NEAR NORMAL VALUES. RAIN CHANCES WILL RETURN SATURDAY
NIGHT OR SUNDAY AS A WARM FRONT LIFTS NORTH ACROSS IN/OH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1134 PM EDT SUN MAY 17 2015
OVERALL THE SHOWERS AND THUNDERSTORMS HAVE BEEN DIMINISHING THIS
EVENING. WILL KEEP ONLY VCSH GOING FOR A FEW SITES TONIGHT. FOG
AND SOME STRATUS COULD DEVELOP. THIS WILL NEED TO BE MONITORED AS
AN ELEVATED RISK FOR IFR EXITS. ANY FOG SHOULD DISSIPATE BY MID
MORNING MONDAY.
I DID ADD VCTS TO KJXN FOR MON AFTN. THE ATMOSPHERE DESTABILIZES
DURING THE DAY. AS A FRONT PUSHES IN THERE COULD BE A FEW STORMS
DEVELOPING ROUGHLY MID AFTERNOON INTO THE LATE AFTERNOON HOURS.
WINDS WILL VEER AND INCREASE THROUGH MON AFTERNOON AS A COOLER
AND DRIER AIRMASS FLOWS IN.
&&
.MARINE...
ISSUED AT 326 PM EDT SUN MAY 17 2015
I CONTINUED THE FOG ADVISORY AS WEB CAMS DO SHOW SOME FOG YET.
WE WILL LIKELY NEED A SMALL CRAFT ADVISORY MONDAY NIGHT AND
TUESDAY AS THE COLD AIR COMES IN.
&&
.HYDROLOGY...
ISSUED AT 1210 AM EDT SUN MAY 17 2015
THE MAIN THREAT THROUGH THE NEXT 24 HOURS WILL BE THE POSSIBILITY
FOR LOCALIZED HEAVY RAINFALL.
A MAJORITY OF THE AREA STREAMS AND RIVERS ARE RUNNING WELL BELOW
ADVISORY LEVELS WITH A COUPLE OF SITES SLIGHTLY BELOW. SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP AND TRAVEL EAST OUT OF THE
UPPER MIDWEST THIS EVENING AND INTO TONIGHT. AREA AVERAGE
RAINFALL MAY RUN FROM A FEW TENTHS OF AN INCH UPWARDS OF A HALF
INCH. LOCALIZED HEAVY POCKETS WILL CREATE GREAT VARIATIONS IN
RAINFALL TOTALS IN SHORT DISTANCES. LOCATIONS THAT ARE AFFECTED BY
HEAVIER RAINFALL MAY EXPERIENCE LOCALIZED PONDING OR TEMPORARY
STREET FLOODING WITH SMALL CREEK AND STREAM FLUCTUATIONS
POSSIBLE. LARGER RIVERS ARE EXPECTED TO REMAIN BELOW ACTION
STAGE THROUGH THE PERIOD AS FEEDBACK TIMES WILL TAKE US INTO
DRIER WEATHER FOR THE UPCOMING WEEK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...JK
AVIATION...MJS
HYDROLOGY...JAM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
739 PM EDT SUN MAY 17 2015
LATEST UPDATE...
AVIATION
.SYNOPSIS...
ISSUED AT 326 PM EDT SUN MAY 17 2015
A STRONG STORM FOR THIS TIME OF YEAR WILL TRACK TOWARD WESTERN
LAKE SUPERIOR BY MONDAY MORNING AND THEN INTO CENTRAL ONTARIO BY
TUESDAY MORNING. THAT WILL CAUSE A STRONG COLD FRONT TO COME
THROUGH THIS AREA MONDAY AFTERNOON. SCATTERED SHOWER AND
THUNDERSTORMS ARE EXPECTED EARLY TONIGHT WELL AHEAD OF THE COLD
FRONT. THEN IT WILL TURN BREEZY AND MUCH COLDER MONDAY NIGHT AND
TUESDAY. HIGHS WILLS STRUGGLE TO MAKE 50 TUESDAY AND THERE COULD
BE A FROST AND FREEZING TEMPERATURES BY WEDNESDAY MORNING.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 326 PM EDT SUN MAY 17 2015
I CONTINUE TO BELIEVE THE RISK FOR STRONG TO SEVERE STORMS IS
RATHER LIMITED TONIGHT. THE BEST DYNAMICS ARE TO OUR WEST AND
NORTH...CLOSER TO THE SYSTEM OVER MINNESOTA AND WISCONSIN. THE
LATEST RUN OF THE RAP MODEL (18Z) CONTINUES TO SHOW THE LOW LEVEL
JET CORE TRACKING THROUGH WESTERN WISCONSIN THIS EVENING LEAVING
SOUTHWEST MICHIGAN IN THE SPEED AREA BEHIND THAT JET. ALSO THE
BEST UPPER DIVERGENCE ASSOCIATED WITH THE POLAR JET CORE IS
EASILY OVER WISCONSIN. WHILE THERE IS A SIGNIFICANT AMOUNT OF
MIXED LAYER CAPE THIS EVENING THE LACK OF DYNAMICS WILL RESULT IN
THE BEST STORMS STAYING OVER WISCONSIN. EVEN SO SOME SHOWERS AND
THUNDERSTORMS WILL TRACK THROUGH OUR EASTERN CWA LATE THIS
AFTERNOON THEN ANOTHER AREA WILL TRACK THROUGH OUR CENTRAL AND
EASTER COUNTIES AFTER 8PM BUT I DO NOT EXPECT ANY SEVERE STORMS AT
THIS TIME.
DRY AIR MOVES IN MONDAY THEN MUCH COLDER AIR MOVES IN BEHIND THE
SYSTEM FOR MONDAY NIGHT INTO TUESDAY NIGHT. THERE IS NOT ENOUGH
MOISTURE FOR SHOWERS IN THE COLD AIR MONDAY NIGHT OR TUESDAY. WE
MAY WILL HAVE FREEZING TEMPERATURES AND WIDESPREAD FROST TUESDAY
NIGHT AS SKIES CLEAR.
.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 326 PM EDT SUN MAY 17 2015
MUCH OF THE EXTENDED PERIOD WILL BE COOL AND DRY...BUT WE SHOULD SEE
A WARM UP BY THE WEEKEND...ALONG WITH A CHANCE OF SHOWERS AND STORMS
RETURNING SATURDAY NIGHT AND SUNDAY.
AN UPPER LOW OVER JAMES BAY WILL KEEP US COOL WITH A NORTHWEST UPPER
FLOW. H8 TEMPS WED THROUGH FRI REMAIN IN THE +1 TO +4C RANGE...
KEEPING DAYTIME HIGH TEMPS BELOW NORMAL...MAINLY IN THE LOW AND MID
60S. THERE SHOULD BE A BACK DOOR COLD FRONT COME THROUGH THURSDAY
NIGHT...BUT IT APPEARS DRY...JUST SUPPLYING A EXTRA SHOT OF COOL AIR
INTO FRIDAY.
A WARM UP SHOULD COMMENCE SATURDAY AS AN UPPER RIDGE BEGINS TO
BUBBLE TOWARD THE AREA PUSHING THE NW FLOW EAST. TEMPS SHOULD
RETURN TO NEAR NORMAL VALUES. RAIN CHANCES WILL RETURN SATURDAY
NIGHT OR SUNDAY AS A WARM FRONT LIFTS NORTH ACROSS IN/OH.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 732 PM EDT SUN MAY 17 2015
SHOWERS AND A FEW THUNDERSTORMS WILL BE POSSIBLE INTO TONIGHT.
CELLS WERE DEVELOPING AT THIS TIME...ESPECIALLY AROUND KJXN AND SW
OF KAZO. BASED ON THE INSTABILITY IN THE AIRMASS...WILL FEATURE
THE HIGHEST PROBABILITY OF STORMS FOR KAZO...KBTL...KJXN AND KLAN.
WILL NEED TO MONITOR TRENDS IN THE DEVELOPING CELLS FOR KGRR AND
KMKG.
ONE BIGGER CHANGE TO THE FORECAST WAS TO FEATURE IFR FOR KMKG. AS
THE MOIST AIRMASS ADVECTS OVER THE COLDER WATERS OF LAKE MI...WE
SHOULD SEE SOME LOWER CLOUDS/FOG MOVE IN FOR KMKG MAINLY AFTER
MIDNIGHT.
AN AFTERNOON STORM LOOKS POSSIBLE INLAND TOWARD KLAN AND KJXN ON
MONDAY...HOWEVER THE COVERAGE LOOKS TOO LIMITED TO INCLUDE IN THE
FORECAST AT THIS TIME. WILL MONITOR TRENDS CLOSELY ON THIS
POTENTIAL.
&&
.MARINE...
ISSUED AT 326 PM EDT SUN MAY 17 2015
I CONTINUED THE FOG ADVISORY AS WEB CAMS DO SHOW SOME FOG YET.
WE WILL LIKELY NEED A SMALL CRAFT ADVISORY MONDAY NIGHT AND
TUESDAY AS THE COLD AIR COMES IN.
&&
.HYDROLOGY...
ISSUED AT 1210 AM EDT SUN MAY 17 2015
THE MAIN THREAT THROUGH THE NEXT 24 HOURS WILL BE THE POSSIBILITY
FOR LOCALIZED HEAVY RAINFALL.
A MAJORITY OF THE AREA STREAMS AND RIVERS ARE RUNNING WELL BELOW
ADVISORY LEVELS WITH A COUPLE OF SITES SLIGHTLY BELOW. SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP AND TRAVEL EAST OUT OF THE
UPPER MIDWEST THIS EVENING AND INTO TONIGHT. AREA AVERAGE
RAINFALL MAY RUN FROM A FEW TENTHS OF AN INCH UPWARDS OF A HALF
INCH. LOCALIZED HEAVY POCKETS WILL CREATE GREAT VARIATIONS IN
RAINFALL TOTALS IN SHORT DISTANCES. LOCATIONS THAT ARE AFFECTED BY
HEAVIER RAINFALL MAY EXPERIENCE LOCALIZED PONDING OR TEMPORARY
STREET FLOODING WITH SMALL CREEK AND STREAM FLUCTUATIONS
POSSIBLE. LARGER RIVERS ARE EXPECTED TO REMAIN BELOW ACTION
STAGE THROUGH THE PERIOD AS FEEDBACK TIMES WILL TAKE US INTO
DRIER WEATHER FOR THE UPCOMING WEEK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...DENSE FOG ADVISORY UNTIL 8 AM EDT MONDAY FOR LMZ844>849.
&&
$$
SYNOPSIS...WDM
SHORT TERM...WDM
LONG TERM...JK
AVIATION...MJS
HYDROLOGY...JAM
MARINE...WDM
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
121 PM EDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EDT SAT MAY 16 2015
WV LOOP AND 00Z RAOBS SHOWS COMPACT SHORTWAVE MOVING OVER NORTHERN
ONTARIO AWAY FM LK SUPERIOR. LOT OF MID-UPR CLOUDS ARE HIDING LAYER
OF STRATUS OVER MAINLY NORTH AND EAST CWA. WHERE CLOUDS THINNED DID
SEE VSBY DROP BLO 2SM AT KIWD...BUT OTHERWISE THE FOG OVER MOST OF
CWA IS PATCHY AT BEST. THICKER MARINE ADVECTION FOG OVER NORTHERN LK
MICHIGAN AS SEEN BY LATEST OBS FM KISQ AND ON BEAVER ISLAND WITH
VSBY 1/2SM OR LESS. RADAR INDICATES WEAK WAVE IS CAUSING PATCHY LGT
RAIN OR DRIZZLE OVER CNTRL CWA...SO CARRIED A MENTION IN GRIDS THRU
MID MORNING AS POCKET OF HIGHER SUB H9 RH SLIDES EAST. AT THE
SFC...RIDGE REMAINS ACROSS AREA WITH SFC LOW DEVELOPING OVER HIGH
PLAINS OF S DAKOTA TO NEB.
BROAD WARM AIR ADVECTION PATTERN TAKES HOLD FM PLAINS TO THE UPPER
MISSISSIPPI RIVER VALLEY AND GREAT LAKES THROUGH TONIGHT. UPPER
LEVELS ARE CHARACTERIZED BY HEIGHT RISES THOUGH...SO EXPECT PRIMARY
CHANCES OF SHOWERS/TSRA TO REMAIN WEST OF UPPER GREAT LAKES THOUGH
TONIGHT...CLOSER TO LEADING EDGE OF HEIGHT FALLS AND PROXIMITY OF
SFC LOW AND ASSOCIATED SFC TROUGH. THERE ARE A COUPLE OF MINOR
EXCEPTIONS TO THIS OVERALL THINKING. FIRST...DESPIRE OVERALL HEIGHT
RISES TODAY...MLCAPES INCREASE TO 500J/KG OVER NORTHERN WI ALONG AND
NORTH OF SFC WARM FRONT. H85-H7 WINDS FM S-SW SUGGEST THAT IF SHRA
OR ISOLD TSRA FORMS NEAR WI BORDER IT COULD ADVECT IN BRIEFLY.
MOISTURE IS LACKING THOUGH PER SOUNDINGS SO KEPT IT DRY. NSSL WRF
AND LATEST HRRR DO HINT AT THIS THOUGH BUT DO NOT SHOW MUCH IN WAY
OF COVERAGE AS LARGE SCALE IS NOT SUPPORTIVE FOR MUCH. SECOND...FOR
TONIGHT THERE IS HINT THAT WEAKER SHORTWAVE EJECTS NORTHEAST OUT OF
CURRENT STRONGER SHRA/TSRA OVER WESTERN KS AND THERE ALSO MAY BE AT
LEAST SOME ELEVATED INSTABILITY /ECMWF INDICATES 1-6KM MUCAPE OVER
100 J/KG/ FOR THE WAVE TO WORK WITH. PUT IN SLIGHT CHANCES FOR
MAINLY SHRA OVER MOST OF WEST AND CNTRL CWA AS AREA WILL BE ON NORTH
EDGE OF H85-H7 MOISTURE TRANSPORT.
EVEN SO...BY FAR THE GREATER CHANCES FOR SHRA/TSRA OVERNIGHT TONIGHT
WILL BE OVER IA/MN ALONG LOW-LEVEL JET AXIS AND WHERE DIFFLUENCE
ALOFT IS MAXIMIZED AHEAD OF STRONG SHORTWAVE LIFTING ACROSS THE
CNTRL PLAINS. WITH BKN-OVC CLOUDS AND STEADY SOUTH WINDS...TEMPS
WILL BE MILD OVER THE CWA WITH MAINLY 50S. TEMPS IN DOWNSLOPE AREAS
NEAR LK SUPERIOR MAY NOT EVEN DROP BLO 60 DEGREES. COOLEST READINGS
NEAR LK MICHIGAN WHERE EAST-SOUTHEAST WINDS WILL RESULT IN AREAS OF
FOG...LOCALLY DENSE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 520 AM EDT SAT MAY 16 2015
SUN AND SUN NIGHT...MODELS SHOW WEAKENING SHORTWAVE LIFTING NE FROM
THE CENTRAL PLAINS INTO THE UPPER LAKES BY SUN NIGHT. THIS WAVE
SHOULD SPREAD SHRA/TSRA INTO THE AREA SUN AFTN AND EVENING AS 40-50
KT LOW-LEVEL JET AND PRECIPITABLE WATER AXIS OF GREATER THAN 1.5
INCHES TRANSLATES E. DEEP LAYER SHEAR OF 35 TO 45 COULD SUPPORT WELL
ORGANIZED STORMS AND ENHANCE SVR TSTM RISK. HOWEVER...AMOUNT OF
INSTABILITY REMAINS IN QUESTION AS CLOUD COVER COULD SUPRESS
INSTABILITY BUILD UP. BOTH THE GFS AND NAM CONTINUE TO INDICATE 400-
800 J/KG MLCAPE NOSING INTO MAINLY GOGEBIC AND IRON COUNTIES BY 00Z
MON AS SPC DAY2 CONVECTIVE OUTLOOK SHOWS SLIGHT RISK BRUSHING THESE
COUNTIES. IT APPEARS THAT IF THERE ARE ANY SVR STORMS...THEY WILL BE
ISOLD/SHORT-LIVED GIVEN THE LACK OF SUBSTANTIAL INSTABILITY...AND
THEY WILL BE CONFINED TO THE W HALF. HIGH TEMPS WELL INTO THE 70S
WILL BE COMMON OVER THE W HALF OF THE FCST AREA ON SUNDAY WITH
PERHAPS A FEW LOCATIONS FAR WEST REACHING LOW 80S. SSE FLOW OFF LAKE
MICHIGAN SHOULD KEEP THE E COOLER...MAINLY LOW 70S INLAND AND MUCH
COOLER (AROUND 60) ALONG SHORELINE. EXPECT DIMINISHING SHRA/TSRA TO
SPREAD E THRU THE EVENING...AND THEN MOST OF THE AREA WILL PROBABLY
BE DRY OVERNIGHT.
MODELS NOW SLOWER THAN YESTERDAYS RUNS WITH PROGRESSION OF SFC LOW
ACROSS THE UPPER GREAT LAKES ON MONDAY AND ONSET OF STRONG CAA ON
BLUSTERY NW WINDS BEHIND IT. IT NOW LOOKS LIKE THE SIGNIFICANT
COOLING WON`T OCCUR UNTIL MON NIGHT INTO TUE. WITH MODELS
ADVERTISING MID LEVEL DRY SLOT PUSHING ACROSS THE AREA...MONDAY MAY
END UP A DRY DAY OVER MUCH OF THE EAST HALF. TO THE W...CYCLONIC
FLOW AND MOISTURE WRAPPING BACK INTO THE AREA COULD BRING SOME ISOLD
-SHRA BACK INTO WRN UPPER MI DURING THE AFTN. WITH THE SLOWER
TREND...MON HIGH TEMPS WILL BE WARMER THAN PREVIOUSLY THOUGHT WITH
EXPECTED READINGS FROM THE MID 50S TO LOWER 60S WEST HALF TO
GENERALLY THE MID TO UPPER 60S INLAND EAST HALF. AS WINDS VEER W-
NW OFF LAKE SUPERIOR...TEMPS WILL FALL IN THE AFTN WEST.
MUCH COLDER AIR THEN ARRIVES FOR MON NIGHT/TUE AS WINDS CONTINUE TO
VEER NW ACROSS THE REST OF THE CWA. GEM/ECMWF SHOW 850MB TEMPS
BOTTOMING OUT AT -8 TO -10C WHILE THE GFS IS AS LOW AS -5C. IF ANY
LIGHT -SHRA LINGER MON NIGHT/TUE...THE PCPN WILL LIKELY MIX WITH OR
CHANGE TO -SHSN...ESPECIALLY OVER HIGHER TERRAIN.
DRY WEATHER IS EXPECTED TO PREVAIL WED THRU FRI AS THE UPPER LAKES
FALL UNDER THE INFLUENCE OF THE ERN CANADA TROF AND DRIER NW FLOW ON
ITS BACKSIDE WITH SFC HIGH PRES ENSCONCED FROM THE NRN PLAINS TO THE
LOWER GREAT LAKES/OHIO VALLEY. MODELS INDICATE THE POTENTIAL FOR
SOME SHORTWAVE ENERGY DROPPING THROUGH THE ERN CANADA TROF AND
PASSING NEAR THE AREA. HOWEVER...PCPN POTENTIAL OF PCPN WOULD BE
VERY LIMITED GIVEN THE LACK OF MOISTURE. SO...WILL CONTINUE MAINLY DRY
FCST FOR WED THRU FRI. AFTER A COOL TUE...TEMPS WILL MODERATE WED
THRU FRI...BUT REMAIN BLO NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 121 PM EDT SAT MAY 16 2015
TOUGH FORECAST TO FIGURE OUT WITH CONFIDENCE FAIRLY LOW. VFR
CONDITIONS WILL CONTINUE INTO THIS EVENING. UPSLOPE STRATUS AND FOG
COULD AFFECT BOTH CMX AND SAW TONIGHT WITH CMX GETTING IT FROM LAKE
SUPERIOR AND SAW GETTING IT WITH SOUTHEAST FLOW FROM LAKE MICHIGAN.
TOUGH TO TELL HOW LOW THE VISIBILITIES WILL GO AND WHAT HEIGHT IT
WILL BE...BUT WENT AHEAD AND WENT MVFR CONDITIONS FOR BOTH SITES
ANYWAY. IWD COULD GET THE SAME THING AND WENT MVFR CONDITIONS LATE
TONIGHT. THINK CMX WILL BE ABLE TO MIX OUT FOR SUN MORNING AND WENT
VFR FOR THEM. IWD AND SAW WILL HAVE A HARDER TIME MIXING OUT AND
KEPT THE LOW CLOUDS IN LONGER.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 520 AM EDT SAT MAY 16 2015
WEAK HIGH PRESSURE OVER THE REGION WILL BRING LIGHT WINDS TODAY. LOW
PRESSURE APPROACHING FROM THE SW WILL ALLOW FOR GRADUALLY INCREASING
E TO SE FLOW TONIGHT INTO SUNDAY. EXPECT GUSTS AS HIGH AS 30 KNOTS
FOR THE HIGHER PLATFORMS. WARM AND MOIST AIR SURGING NORTH AHEAD OF
THE LOW WILL KEEP THE CHANCE OF FOG IN THE FORECAST THROUGH MONDAY
MORNING BEFORE WINDS TURN NW AND DRIER AIR SCOURS OUT THE FOG. THE
LOW WILL CROSS LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. THIS WILL
USHER IN NW TO NNW WINDS OF 20 TO 30 KTS MONDAY NIGHT AND
TUESDAY...WITH A FEW GALE FORCE GUSTS TO 35 KNOTS POSSIBLE FOR THE
EAST HALF. BROAD HIGH PRESSURE WILL THEN BUILD ACROSS THE REGION
WEDNESDAY THROUGH FRIDAY...BRINGING LIGHT WESTERLY FLOW UNDER 20
KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ248-250.
&&
$$
SHORT TERM...JLA
LONG TERM...VOSS
AVIATION...07
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
728 AM EDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EDT SAT MAY 16 2015
WV LOOP AND 00Z RAOBS SHOWS COMPACT SHORTWAVE MOVING OVER NORTHERN
ONTARIO AWAY FM LK SUPERIOR. LOT OF MID-UPR CLOUDS ARE HIDING LAYER
OF STRATUS OVER MAINLY NORTH AND EAST CWA. WHERE CLOUDS THINNED DID
SEE VSBY DROP BLO 2SM AT KIWD...BUT OTHERWISE THE FOG OVER MOST OF
CWA IS PATCHY AT BEST. THICKER MARINE ADVECTION FOG OVER NORTHERN LK
MICHIGAN AS SEEN BY LATEST OBS FM KISQ AND ON BEAVER ISLAND WITH
VSBY 1/2SM OR LESS. RADAR INDICATES WEAK WAVE IS CAUSING PATCHY LGT
RAIN OR DRIZZLE OVER CNTRL CWA...SO CARRIED A MENTION IN GRIDS THRU
MID MORNING AS POCKET OF HIGHER SUB H9 RH SLIDES EAST. AT THE
SFC...RIDGE REMAINS ACROSS AREA WITH SFC LOW DEVELOPING OVER HIGH
PLAINS OF S DAKOTA TO NEB.
BROAD WARM AIR ADVECTION PATTERN TAKES HOLD FM PLAINS TO THE UPPER
MISSISSIPPI RIVER VALLEY AND GREAT LAKES THROUGH TONIGHT. UPPER
LEVELS ARE CHARACTERIZED BY HEIGHT RISES THOUGH...SO EXPECT PRIMARY
CHANCES OF SHOWERS/TSRA TO REMAIN WEST OF UPPER GREAT LAKES THOUGH
TONIGHT...CLOSER TO LEADING EDGE OF HEIGHT FALLS AND PROXIMITY OF
SFC LOW AND ASSOCIATED SFC TROUGH. THERE ARE A COUPLE OF MINOR
EXCEPTIONS TO THIS OVERALL THINKING. FIRST...DESPIRE OVERALL HEIGHT
RISES TODAY...MLCAPES INCREASE TO 500J/KG OVER NORTHERN WI ALONG AND
NORTH OF SFC WARM FRONT. H85-H7 WINDS FM S-SW SUGGEST THAT IF SHRA
OR ISOLD TSRA FORMS NEAR WI BORDER IT COULD ADVECT IN BRIEFLY.
MOISTURE IS LACKING THOUGH PER SOUNDINGS SO KEPT IT DRY. NSSL WRF
AND LATEST HRRR DO HINT AT THIS THOUGH BUT DO NOT SHOW MUCH IN WAY
OF COVERAGE AS LARGE SCALE IS NOT SUPPORTIVE FOR MUCH. SECOND...FOR
TONIGHT THERE IS HINT THAT WEAKER SHORTWAVE EJECTS NORTHEAST OUT OF
CURRENT STRONGER SHRA/TSRA OVER WESTERN KS AND THERE ALSO MAY BE AT
LEAST SOME ELEVATED INSTABILITY /ECMWF INDICATES 1-6KM MUCAPE OVER
100 J/KG/ FOR THE WAVE TO WORK WITH. PUT IN SLIGHT CHANCES FOR
MAINLY SHRA OVER MOST OF WEST AND CNTRL CWA AS AREA WILL BE ON NORTH
EDGE OF H85-H7 MOISTURE TRANSPORT.
EVEN SO...BY FAR THE GREATER CHANCES FOR SHRA/TSRA OVERNIGHT TONIGHT
WILL BE OVER IA/MN ALONG LOW-LEVEL JET AXIS AND WHERE DIFFLUENCE
ALOFT IS MAXIMIZED AHEAD OF STRONG SHORTWAVE LIFTING ACROSS THE
CNTRL PLAINS. WITH BKN-OVC CLOUDS AND STEADY SOUTH WINDS...TEMPS
WILL BE MILD OVER THE CWA WITH MAINLY 50S. TEMPS IN DOWNSLOPE AREAS
NEAR LK SUPERIOR MAY NOT EVEN DROP BLO 60 DEGREES. COOLEST READINGS
NEAR LK MICHIGAN WHERE EAST-SOUTHEAST WINDS WILL RESULT IN AREAS OF
FOG...LOCALLY DENSE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 520 AM EDT SAT MAY 16 2015
SUN AND SUN NIGHT...MODELS SHOW WEAKENING SHORTWAVE LIFTING NE FROM
THE CENTRAL PLAINS INTO THE UPPER LAKES BY SUN NIGHT. THIS WAVE
SHOULD SPREAD SHRA/TSRA INTO THE AREA SUN AFTN AND EVENING AS 40-50
KT LOW-LEVEL JET AND PRECIPITABLE WATER AXIS OF GREATER THAN 1.5
INCHES TRANSLATES E. DEEP LAYER SHEAR OF 35 TO 45 COULD SUPPORT WELL
ORGANIZED STORMS AND ENHANCE SVR TSTM RISK. HOWEVER...AMOUNT OF
INSTABILITY REMAINS IN QUESTION AS CLOUD COVER COULD SUPRESS
INSTABILITY BUILD UP. BOTH THE GFS AND NAM CONTINUE TO INDICATE 400-
800 J/KG MLCAPE NOSING INTO MAINLY GOGEBIC AND IRON COUNTIES BY 00Z
MON AS SPC DAY2 CONVECTIVE OUTLOOK SHOWS SLIGHT RISK BRUSHING THESE
COUNTIES. IT APPEARS THAT IF THERE ARE ANY SVR STORMS...THEY WILL BE
ISOLD/SHORT-LIVED GIVEN THE LACK OF SUBSTANTIAL INSTABILITY...AND
THEY WILL BE CONFINED TO THE W HALF. HIGH TEMPS WELL INTO THE 70S
WILL BE COMMON OVER THE W HALF OF THE FCST AREA ON SUNDAY WITH
PERHAPS A FEW LOCATIONS FAR WEST REACHING LOW 80S. SSE FLOW OFF LAKE
MICHIGAN SHOULD KEEP THE E COOLER...MAINLY LOW 70S INLAND AND MUCH
COOLER (AROUND 60) ALONG SHORELINE. EXPECT DIMINISHING SHRA/TSRA TO
SPREAD E THRU THE EVENING...AND THEN MOST OF THE AREA WILL PROBABLY
BE DRY OVERNIGHT.
MODELS NOW SLOWER THAN YESTERDAYS RUNS WITH PROGRESSION OF SFC LOW
ACROSS THE UPPER GREAT LAKES ON MONDAY AND ONSET OF STRONG CAA ON
BLUSTERY NW WINDS BEHIND IT. IT NOW LOOKS LIKE THE SIGNIFICANT
COOLING WON`T OCCUR UNTIL MON NIGHT INTO TUE. WITH MODELS
ADVERTISING MID LEVEL DRY SLOT PUSHING ACROSS THE AREA...MONDAY MAY
END UP A DRY DAY OVER MUCH OF THE EAST HALF. TO THE W...CYCLONIC
FLOW AND MOISTURE WRAPPING BACK INTO THE AREA COULD BRING SOME ISOLD
-SHRA BACK INTO WRN UPPER MI DURING THE AFTN. WITH THE SLOWER
TREND...MON HIGH TEMPS WILL BE WARMER THAN PREVIOUSLY THOUGHT WITH
EXPECTED READINGS FROM THE MID 50S TO LOWER 60S WEST HALF TO
GENERALLY THE MID TO UPPER 60S INLAND EAST HALF. AS WINDS VEER W-
NW OFF LAKE SUPERIOR...TEMPS WILL FALL IN THE AFTN WEST.
MUCH COLDER AIR THEN ARRIVES FOR MON NIGHT/TUE AS WINDS CONTINUE TO
VEER NW ACROSS THE REST OF THE CWA. GEM/ECMWF SHOW 850MB TEMPS
BOTTOMING OUT AT -8 TO -10C WHILE THE GFS IS AS LOW AS -5C. IF ANY
LIGHT -SHRA LINGER MON NIGHT/TUE...THE PCPN WILL LIKELY MIX WITH OR
CHANGE TO -SHSN...ESPECIALLY OVER HIGHER TERRAIN.
DRY WEATHER IS EXPECTED TO PREVAIL WED THRU FRI AS THE UPPER LAKES
FALL UNDER THE INFLUENCE OF THE ERN CANADA TROF AND DRIER NW FLOW ON
ITS BACKSIDE WITH SFC HIGH PRES ENSCONCED FROM THE NRN PLAINS TO THE
LOWER GREAT LAKES/OHIO VALLEY. MODELS INDICATE THE POTENTIAL FOR
SOME SHORTWAVE ENERGY DROPPING THROUGH THE ERN CANADA TROF AND
PASSING NEAR THE AREA. HOWEVER...PCPN POTENTIAL OF PCPN WOULD BE
VERY LIMITED GIVEN THE LACK OF MOISTURE. SO...WILL CONTINUE MAINLY DRY
FCST FOR WED THRU FRI. AFTER A COOL TUE...TEMPS WILL MODERATE WED
THRU FRI...BUT REMAIN BLO NORMAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 728 AM EDT SAT MAY 16 2015
THICKER CLOUDS IN MID-LEVELS EARLY THIS MORNING HAVE PROHIBITED
WIDESPREAD FOG FROM FORMING. SHALLOW GROUND FOG EARLY AT KIWD BUT
OTHERWISE EXPECT MINIMAL FOG ISSUES REST OF THE DAY AND INTO
TONIGHT. SCT-BKN VFR CLOUDS WILL CONTINUE AT ALL THE TAF SITES INTO
TONIGHT. MIGHT SEE AN ISOLD SHRA OR TSRA LATE TONIGHT...BUT COVERAGE
AND PROBABILITY IS TOO LOW TO INCLUDE FOR THESE TAFS.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 520 AM EDT SAT MAY 16 2015
WEAK HIGH PRESSURE OVER THE REGION WILL BRING LIGHT WINDS TODAY. LOW
PRESSURE APPROACHING FROM THE SW WILL ALLOW FOR GRADUALLY INCREASING
E TO SE FLOW TONIGHT INTO SUNDAY. EXPECT GUSTS AS HIGH AS 30 KNOTS
FOR THE HIGHER PLATFORMS. WARM AND MOIST AIR SURGING NORTH AHEAD OF
THE LOW WILL KEEP THE CHANCE OF FOG IN THE FORECAST THROUGH MONDAY
MORNING BEFORE WINDS TURN NW AND DRIER AIR SCOURS OUT THE FOG. THE
LOW WILL CROSS LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. THIS WILL
USHER IN NW TO NNW WINDS OF 20 TO 30 KTS MONDAY NIGHT AND
TUESDAY...WITH A FEW GALE FORCE GUSTS TO 35 KNOTS POSSIBLE FOR THE
EAST HALF. BROAD HIGH PRESSURE WILL THEN BUILD ACROSS THE REGION
WEDNESDAY THROUGH FRIDAY...BRINGING LIGHT WESTERLY FLOW UNDER 20
KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ248-250.
&&
$$
SHORT TERM...JLA
LONG TERM...VOSS
AVIATION...JLA
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
521 AM EDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 520 AM EDT SAT MAY 16 2015
WV LOOP AND 00Z RAOBS SHOWS COMPACT SHORTWAVE MOVING OVER NORTHERN
ONTARIO AWAY FM LK SUPERIOR. LOT OF MID-UPR CLOUDS ARE HIDING LAYER
OF STRATUS OVER MAINLY NORTH AND EAST CWA. WHERE CLOUDS THINNED DID
SEE VSBY DROP BLO 2SM AT KIWD...BUT OTHERWISE THE FOG OVER MOST OF
CWA IS PATCHY AT BEST. THICKER MARINE ADVECTION FOG OVER NORTHERN LK
MICHIGAN AS SEEN BY LATEST OBS FM KISQ AND ON BEAVER ISLAND WITH
VSBY 1/2SM OR LESS. RADAR INDICATES WEAK WAVE IS CAUSING PATCHY LGT
RAIN OR DRIZZLE OVER CNTRL CWA...SO CARRIED A MENTION IN GRIDS THRU
MID MORNING AS POCKET OF HIGHER SUB H9 RH SLIDES EAST. AT THE
SFC...RIDGE REMAINS ACROSS AREA WITH SFC LOW DEVELOPING OVER HIGH
PLAINS OF S DAKOTA TO NEB.
BROAD WARM AIR ADVECTION PATTERN TAKES HOLD FM PLAINS TO THE UPPER
MISSISSIPPI RIVER VALLEY AND GREAT LAKES THROUGH TONIGHT. UPPER
LEVELS ARE CHARACTERIZED BY HEIGHT RISES THOUGH...SO EXPECT PRIMARY
CHANCES OF SHOWERS/TSRA TO REMAIN WEST OF UPPER GREAT LAKES THOUGH
TONIGHT...CLOSER TO LEADING EDGE OF HEIGHT FALLS AND PROXIMITY OF
SFC LOW AND ASSOCIATED SFC TROUGH. THERE ARE A COUPLE OF MINOR
EXCEPTIONS TO THIS OVERALL THINKING. FIRST...DESPIRE OVERALL HEIGHT
RISES TODAY...MLCAPES INCREASE TO 500J/KG OVER NORTHERN WI ALONG AND
NORTH OF SFC WARM FRONT. H85-H7 WINDS FM S-SW SUGGEST THAT IF SHRA
OR ISOLD TSRA FORMS NEAR WI BORDER IT COULD ADVECT IN BRIEFLY.
MOISTURE IS LACKING THOUGH PER SOUNDINGS SO KEPT IT DRY. NSSL WRF
AND LATEST HRRR DO HINT AT THIS THOUGH BUT DO NOT SHOW MUCH IN WAY
OF COVERAGE AS LARGE SCALE IS NOT SUPPORTIVE FOR MUCH. SECOND...FOR
TONIGHT THERE IS HINT THAT WEAKER SHORTWAVE EJECTS NORTHEAST OUT OF
CURRENT STRONGER SHRA/TSRA OVER WESTERN KS AND THERE ALSO MAY BE AT
LEAST SOME ELEVATED INSTABILITY /ECMWF INDICATES 1-6KM MUCAPE OVER
100 J/KG/ FOR THE WAVE TO WORK WITH. PUT IN SLIGHT CHANCES FOR
MAINLY SHRA OVER MOST OF WEST AND CNTRL CWA AS AREA WILL BE ON NORTH
EDGE OF H85-H7 MOISTURE TRANSPORT.
EVEN SO...BY FAR THE GREATER CHANCES FOR SHRA/TSRA OVERNIGHT TONIGHT
WILL BE OVER IA/MN ALONG LOW-LEVEL JET AXIS AND WHERE DIFFLUENCE
ALOFT IS MAXIMIZED AHEAD OF STRONG SHORTWAVE LIFTING ACROSS THE
CNTRL PLAINS. WITH BKN-OVC CLOUDS AND STEADY SOUTH WINDS...TEMPS
WILL BE MILD OVER THE CWA WITH MAINLY 50S. TEMPS IN DOWNSLOPE AREAS
NEAR LK SUPERIOR MAY NOT EVEN DROP BLO 60 DEGREES. COOLEST READINGS
NEAR LK MICHIGAN WHERE EAST-SOUTHEAST WINDS WILL RESULT IN AREAS OF
FOG...LOCALLY DENSE.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 520 AM EDT SAT MAY 16 2015
SUN AND SUN NIGHT...MODELS SHOW WEAKENING SHORTWAVE LIFTING NE FROM
THE CENTRAL PLAINS INTO THE UPPER LAKES BY SUN NIGHT. THIS WAVE
SHOULD SPREAD SHRA/TSRA INTO THE AREA SUN AFTN AND EVENING AS 40-50
KT LOW-LEVEL JET AND PRECIPITABLE WATER AXIS OF GREATER THAN 1.5
INCHES TRANSLATES E. DEEP LAYER SHEAR OF 35 TO 45 COULD SUPPORT WELL
ORGANIZED STORMS AND ENHANCE SVR TSTM RISK. HOWEVER...AMOUNT OF
INSTABILITY REMAINS IN QUESTION AS CLOUD COVER COULD SUPRESS
INSTABILITY BUILD UP. BOTH THE GFS AND NAM CONTINUE TO INDICATE 400-
800 J/KG MLCAPE NOSING INTO MAINLY GOGEBIC AND IRON COUNTIES BY 00Z
MON AS SPC DAY2 CONVECTIVE OUTLOOK SHOWS SLIGHT RISK BRUSHING THESE
COUNTIES. IT APPEARS THAT IF THERE ARE ANY SVR STORMS...THEY WILL BE
ISOLD/SHORT-LIVED GIVEN THE LACK OF SUBSTANTIAL INSTABILITY...AND
THEY WILL BE CONFINED TO THE W HALF. HIGH TEMPS WELL INTO THE 70S
WILL BE COMMON OVER THE W HALF OF THE FCST AREA ON SUNDAY WITH
PERHAPS A FEW LOCATIONS FAR WEST REACHING LOW 80S. SSE FLOW OFF LAKE
MICHIGAN SHOULD KEEP THE E COOLER...MAINLY LOW 70S INLAND AND MUCH
COOLER (AROUND 60) ALONG SHORELINE. EXPECT DIMINISHING SHRA/TSRA TO
SPREAD E THRU THE EVENING...AND THEN MOST OF THE AREA WILL PROBABLY
BE DRY OVERNIGHT.
MODELS NOW SLOWER THAN YESTERDAYS RUNS WITH PROGRESSION OF SFC LOW
ACROSS THE UPPER GREAT LAKES ON MONDAY AND ONSET OF STRONG CAA ON
BLUSTERY NW WINDS BEHIND IT. IT NOW LOOKS LIKE THE SIGNIFICANT
COOLING WON`T OCCUR UNTIL MON NIGHT INTO TUE. WITH MODELS
ADVERTISING MID LEVEL DRY SLOT PUSHING ACROSS THE AREA...MONDAY MAY
END UP A DRY DAY OVER MUCH OF THE EAST HALF. TO THE W...CYCLONIC
FLOW AND MOISTURE WRAPPING BACK INTO THE AREA COULD BRING SOME ISOLD
-SHRA BACK INTO WRN UPPER MI DURING THE AFTN. WITH THE SLOWER
TREND...MON HIGH TEMPS WILL BE WARMER THAN PREVIOUSLY THOUGHT WITH
EXPECTED READINGS FROM THE MID 50S TO LOWER 60S WEST HALF TO
GENERALLY THE MID TO UPPER 60S INLAND EAST HALF. AS WINDS VEER W-
NW OFF LAKE SUPERIOR...TEMPS WILL FALL IN THE AFTN WEST.
MUCH COLDER AIR THEN ARRIVES FOR MON NIGHT/TUE AS WINDS CONTINUE TO
VEER NW ACROSS THE REST OF THE CWA. GEM/ECMWF SHOW 850MB TEMPS
BOTTOMING OUT AT -8 TO -10C WHILE THE GFS IS AS LOW AS -5C. IF ANY
LIGHT -SHRA LINGER MON NIGHT/TUE...THE PCPN WILL LIKELY MIX WITH OR
CHANGE TO -SHSN...ESPECIALLY OVER HIGHER TERRAIN.
DRY WEATHER IS EXPECTED TO PREVAIL WED THRU FRI AS THE UPPER LAKES
FALL UNDER THE INFLUENCE OF THE ERN CANADA TROF AND DRIER NW FLOW ON
ITS BACKSIDE WITH SFC HIGH PRES ENSCONCED FROM THE NRN PLAINS TO THE
LOWER GREAT LAKES/OHIO VALLEY. MODELS INDICATE THE POTENTIAL FOR
SOME SHORTWAVE ENERGY DROPPING THROUGH THE ERN CANADA TROF AND
PASSING NEAR THE AREA. HOWEVER...PCPN POTENTIAL OF PCPN WOULD BE
VERY LIMITED GIVEN THE LACK OF MOISTURE. SO...WILL CONTINUE MAINLY DRY
FCST FOR WED THRU FRI. AFTER A COOL TUE...TEMPS WILL MODERATE WED
THRU FRI...BUT REMAIN BLO NORMAL. &&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 142 AM EDT SAT MAY 16 2015
LIGHT WINDS AND ANTECEDENT MOISTURE CONTINUE TO MAKE THE FORECAST A
CHALLENGE THIS MORNING. THERE CONTINUES TO BE A POTENTIAL FOR LOW CIGS
AND FOG AT ALL THREE SITES. HOWEVER ONLY KSAW AT IFR CIGS AT THIS
TIME WHILE KCMX AND KIWD ARE MVFR. CONCERN IS 0Z NAM BUFKIT SUPPORTS
LOW CLOUDS/FOG AT ALL THREE SITES...HOWEVER THE NAM HAS BEEN NOTED AS
BEING A BIT AGGRESSIVE WITH LOW LEVEL MOISTURE. AT THIS TIME...STILL
EXPECT IFR CONDITIONS AT KCMX AND KSAW FOR A TIME OVERNIGHT BUT DO
NOT EXPECT RESTRICTIONS TO BE AS SIGNIFICANT AS SUGGESTED BY THE NAM.
FORTUNATELY...LOW CLOUDS AND FOG WILL LIFT AFTER SUNRISE WITH VFR
CONDITIONS PREVAILING BY 15Z AT THE LATEST AT KCMX AND KSAW. THERE IS
A SLIGHT CHANCE OF SHOWERS AND PERHAPS A THUNDERSTORMS MOVING INTO
THE KIWD AREA CLOSE TO THE END OF THE FORECAST BUT FOR NOW HAVE LEFT
THIS OUT OF THE CURRENT DUE TO A HIGH DEGREE OF UNCERTAINTY WITH THE
TIMING OF THE ARRIVAL OF THE CONVECTION.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 520 AM EDT SAT MAY 16 2015
WEAK HIGH PRESSURE OVER THE REGION WILL BRING LIGHT WINDS TODAY. LOW
PRESSURE APPROACHING FROM THE SW WILL ALLOW FOR GRADUALLY INCREASING
E TO SE FLOW TONIGHT INTO SUNDAY. EXPECT GUSTS AS HIGH AS 30 KNOTS
FOR THE HIGHER PLATFORMS. WARM AND MOIST AIR SURGING NORTH AHEAD OF
THE LOW WILL KEEP THE CHANCE OF FOG IN THE FORECAST THROUGH MONDAY
MORNING BEFORE WINDS TURN NW AND DRIER AIR SCOURS OUT THE FOG. THE
LOW WILL CROSS LAKE SUPERIOR MONDAY AFTERNOON AND EVENING. THIS WILL
USHER IN NW TO NNW WINDS OF 20 TO 30 KTS MONDAY NIGHT AND
TUESDAY...WITH A FEW GALE FORCE GUSTS TO 35 KNOTS POSSIBLE FOR THE
EAST HALF. BROAD HIGH PRESSURE WILL THEN BUILD ACROSS THE REGION
WEDNESDAY THROUGH FRIDAY...BRINGING LIGHT WESTERLY FLOW UNDER 20
KNOTS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
DENSE FOG ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ248-250.
&&
$$
SHORT TERM...JLA
LONG TERM...VOSS
AVIATION...RJT
MARINE...JLA
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
925 PM CDT SUN MAY 17 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 412 PM CDT SUN MAY 17 2015
THUNDERSTORMS HAVE BECOME FAIRLY WIDESPREAD THIS AFTERNOON TO THE
EAST OF A COLD FRONT THAT IS ADVANCING EAST ACROSS MN. THE SFC LOW
DRIVING THIS FRONT WAS DOWN TO 995 MB AND SPINNING RATHER
AGGRESSIVELY ACROSS NE SODAK. BASED ON SFC PRESSURE FALLS...THIS LOW
WILL BE ON ITS WAY OFF TO THE ARROWHEAD TONIGHT. WE HAVE QUITE THE
CONTRAST IN AIRMASSES ACROSS THE SYSTEM...WITH SUMMER-LIKE AIR TO
ITS EAST WITH TEMPERATURES IN THE 70S AND DEWPS IN THE 60S...WHILE
WEST OF THE LOW...TEMPERATURES ARE DOWN IN THE MID 30S ACROSS NODAK.
IN FACT...IT IS COLD ENOUGH ON THE WRN EDGE OF THE PRECIP SHIELD
THAT WE ARE SEEING A RAIN/SNOW MIX THIS AFTERNOON.
FOR THE REST OF TODAY...LIKE THE IDEA THAT THE HRRR HAS BEEN RUNNING
WITH ALL DAY THAT MATCHES WELL WITH REALITY NOW. AND THAT IS FOR THE
WIDESPREAD DISCRETE CELLS TO CONTINUE THROUGH THE EVENING AHEAD OF
THE COLD FRONT. WE HAVE SEEN SBCAPE INCREASE TO BETWEEN 1000 AND
1500 J/KG...BUT WITH LITTLE CIN IN PLACE...WE ARE BASICALLY POPPING
CONVECTION AS SOON AS INSTABILITY DEVELOPS. MID-LEVEL LAPSE RATES
ARE PRETTY WEAK THOUGH...WHICH IS A BIG LIMITING FACTOR IN THE SVR.
STILL...FREEZING LEVELS HAVE DROPPED FROM ALMOST 12K FT AGL
YESTERDAY TO BETWEEN 8K AND 9K FEET TODAY...WHICH WILL CONTINUE TO
ALLOW FOR THE THREAT FOR MARGINALLY SVR HAIL THROUGH THE EVENING.
GIVEN THE DEPTH OF THE SYSTEM IN TO OUR NW...WE ARE SEEING LOTS OF
WIND THROUGH PRETTY MUCH THE WHOLE DEPTH OF THE ATMO...SO THESE
SHOWERS WILL LIKELY BE ABLE TO MIX SOME OF THAT DOWN...LEADING TO
SOME GUSTY WINDS AS WELL. TORNADO THREAT DOES NOT LOOK AS GOOD AS
YESTERDAY...WHEN WE HAD A WARM FRONT DRAPED ACROSS THE STATE...BUT
THE RAP HAS BEEN SHOWING 0-1 SHEAR INCREASING LATE THIS AFTERNOON
ACROSS ERN MN/WRN WI...WHERE THE BEST CHANCE FOR SEEING A BRIEF
TORNADO WOULD EXIST.
FOR TONIGHT...THE BIG THING WE WILL SEE IS STRONG CAA AS THE LOW
PUSHES TOWARD THE ARROWHEAD. THIS WILL LEAD TO SOME AGGRESSIVE
TEMPERATURE DROPS OVERNIGHT...WHERE LOWS IN WRN MN WILL FALL BACK
INTO THE MID 30S...OR ABOUT 35 DEGREES COLDER THAN THE HIGHS WERE
THIS AFTERNOON. IN ADDITION TO THE COLD AIR...WE WILL SEE WRAP
AROUND PRECIP DIP DOWN ABOUT AS FAR SOUTH AS A MADISON TO MILLE LACS
LAKE LINE. FORECAST SOUNDINGS IN THIS AREA ARE ALSO COLD ENOUGH TO
SHOW A RAIN/SLEET MIX DEVELOPING LATE TONIGHT. IN FACT...THE NAM
WOULD SAY THE P-TYPE AT AXN WILL BE ALL SLEET TOMORROW MORNING...SO
DID INTRODUCE A PRECIP MIX INTO THE GRIDS. BESIDE THE PRECIP...WINDS
WILL BE STRONG AS WELL. TOP OF THE CHANNEL MIX DOWN AT MOST SITES IN
MN IS OVER 40 KTS. WE ARE RIGHT ON THE CUSP OF NEEDING A WIND
ADVY...BUT DECIDED TO HOLD OFF ON ONE FOR NOW AND WILL LET THE
SEVERE POTENTIAL PLAY OUT BEFORE HOISTING A WIND ADVY.
FOR MONDAY...THERE IS NO WAY AROUND IT...IT WILL BE A RAW DAY. NAM
HAS H85 TEMPS DROPPING TO BETWEEN -5 AND -8C...WHICH IS BELOW THE
CLIMATOLOGICAL RECORD FOR H85 TEMPS FOR THE DAY AT STC/MPX. THROW IN
THE MOSTLY CLOUDY SKIES...AND HAVE HIGH CONFIDENCE IN HIGHS STAYING
IN THE 40S...WITH HIGHS ONLY IN THE 30S OUT TOWARD AXN. THESE VALUES
WILL BE IN THE 25 TO 35 DEGREES BELOW NORMAL RANGE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 412 PM CDT SUN MAY 17 2015
THE AFOREMENTIONED STRONG COLD ADVECTION ON MONDAY WILL KEEP THE
LOCAL AREA COOL ON TUESDAY AS WELL WITH HIGHS LIKELY REMAINING IN
THE 50S. THE TROUGH MOVES EAST BY WEDNESDAY AND EAST COAST TROUGH
SHEARS OUT BEFORE ADVANCING OUT OF THE ROCKIES. THEREFORE WE
SHOULD SEE DRY WEATHER AND COOL TO MILD TEMPERATURES THROUGH THE
WEEK...WITH A SLOW WARMING TREND TIME. WE EXPECT TUESDAY AND
WEDNESDAY MORNINGS TO FALL INTO THE 30S ACROSS CENTRAL MN AND WEST
CENTRAL WI...SO WE COULD SEE A LITTLE FROST IF WE MANAGE TO
GET CLEARING AND THE WINDS STAY CALM. WEDNESDAY MORNING HAS A
BETTER CHANCE OF A CALM WIND AND AT LEAST PARTIAL CLEARING. THE
NEXT CHANCE FOR THUNDERSTORMS WILL LIKELY HOLD OFF UNTIL THE
WEEKEND WHEN ANOTHER TROUGH APPROACHES THE REGION FROM THE PLAINS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 925 PM CDT SUN MAY 17 2015
SCATTERED SHOWERS WILL CONTINUE IN EASTERN MN THROUGH BY 03Z AND
ABOUT 04-05Z IN WESTERN WI. THERE WILL BE SEVERAL HOURS OF VFR IN
MN /LONGER IN WI/ BEFORE AN MVFR STRATUS DECK MOVES IN LATE THIS
EVENING AND TONIGHT AND LINGERS THROUGH THE DAY TOMORROW. IFR IS
POSSIBLE ACROSS PORTIONS OF CENTRAL MN...BUT MOST OF THE TAF SITES
SHOULD REMAIN BETWEEN 1500-2500FT FOR CLOUD BASES. STRONG WINDS
RIGHT ALONG OR BEHIND THE SHOWERS LOOK TO CONTINUE THIS EVENING
WITH GUSTS BETWEEN 40-50MPH BEING OBSERVED AT MANY SITES.
KMSP...
SHOWERS HAVE ENDED...BUT THE BIG CONCERN IS NOW THE STRONG SW
WINDS AND CROSSWIND COMPONENT THAT HAS CAUGHT US A LITTLE OFF
GAURD. WE THIN THE STRONGEST WINDS WILL SUBSIDE BY 03Z...BACK
UNDER 35KTS...BUT THE DIRECTION MAY TAKE ANOTHER 1-2 HOURS /05Z/
TO BACK MORE TO THE WEST TONIGHT. OTHERWISE...WE HAVE MEDIUM TO
HIGH CONFIDENCE OF 2000-2200FT CEILINGS AT THE AIRPORT BEFORE THE
MONDAY MORNING COMMUTE...BUT WE ARE NOT TOO CONFIDENT THEY WILL BE
BELOW 1700FT. WE SHOULD HAVE A MUCH BETTER IDEA AT THE 06Z AND 09Z
UPDATES.
/OUTLOOK FOR KMSP/
TUE...MVFR CIGS POSSIBLE EARLY. WINDS N AT 10 KTS.
WED...VFR. WINDS N 5 KTS.
THU...VFR. WINDS NNW 5 TO 10 KTS.
FRI...VFR. WINDS VARIABLE 0 TO 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND ADVISORY UNTIL 4 AM CDT MONDAY FOR MNZ047-054>056-064-065-
073-074-082-091.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...CLF
AVIATION...CLF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
700 PM CDT SUN MAY 17 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 412 PM CDT SUN MAY 17 2015
THUNDERSTORMS HAVE BECOME FAIRLY WIDESPREAD THIS AFTERNOON TO THE
EAST OF A COLD FRONT THAT IS ADVANCING EAST ACROSS MN. THE SFC LOW
DRIVING THIS FRONT WAS DOWN TO 995 MB AND SPINNING RATHER
AGGRESSIVELY ACROSS NE SODAK. BASED ON SFC PRESSURE FALLS...THIS LOW
WILL BE ON ITS WAY OFF TO THE ARROWHEAD TONIGHT. WE HAVE QUITE THE
CONTRAST IN AIRMASSES ACROSS THE SYSTEM...WITH SUMMER-LIKE AIR TO
ITS EAST WITH TEMPERATURES IN THE 70S AND DEWPS IN THE 60S...WHILE
WEST OF THE LOW...TEMPERATURES ARE DOWN IN THE MID 30S ACROSS NODAK.
IN FACT...IT IS COLD ENOUGH ON THE WRN EDGE OF THE PRECIP SHIELD
THAT WE ARE SEEING A RAIN/SNOW MIX THIS AFTERNOON.
FOR THE REST OF TODAY...LIKE THE IDEA THAT THE HRRR HAS BEEN RUNNING
WITH ALL DAY THAT MATCHES WELL WITH REALITY NOW. AND THAT IS FOR THE
WIDESPREAD DISCRETE CELLS TO CONTINUE THROUGH THE EVENING AHEAD OF
THE COLD FRONT. WE HAVE SEEN SBCAPE INCREASE TO BETWEEN 1000 AND
1500 J/KG...BUT WITH LITTLE CIN IN PLACE...WE ARE BASICALLY POPPING
CONVECTION AS SOON AS INSTABILITY DEVELOPS. MID-LEVEL LAPSE RATES
ARE PRETTY WEAK THOUGH...WHICH IS A BIG LIMITING FACTOR IN THE SVR.
STILL...FREEZING LEVELS HAVE DROPPED FROM ALMOST 12K FT AGL
YESTERDAY TO BETWEEN 8K AND 9K FEET TODAY...WHICH WILL CONTINUE TO
ALLOW FOR THE THREAT FOR MARGINALLY SVR HAIL THROUGH THE EVENING.
GIVEN THE DEPTH OF THE SYSTEM IN TO OUR NW...WE ARE SEEING LOTS OF
WIND THROUGH PRETTY MUCH THE WHOLE DEPTH OF THE ATMO...SO THESE
SHOWERS WILL LIKELY BE ABLE TO MIX SOME OF THAT DOWN...LEADING TO
SOME GUSTY WINDS AS WELL. TORNADO THREAT DOES NOT LOOK AS GOOD AS
YESTERDAY...WHEN WE HAD A WARM FRONT DRAPED ACROSS THE STATE...BUT
THE RAP HAS BEEN SHOWING 0-1 SHEAR INCREASING LATE THIS AFTERNOON
ACROSS ERN MN/WRN WI...WHERE THE BEST CHANCE FOR SEEING A BRIEF
TORNADO WOULD EXIST.
FOR TONIGHT...THE BIG THING WE WILL SEE IS STRONG CAA AS THE LOW
PUSHES TOWARD THE ARROWHEAD. THIS WILL LEAD TO SOME AGGRESSIVE
TEMPERATURE DROPS OVERNIGHT...WHERE LOWS IN WRN MN WILL FALL BACK
INTO THE MID 30S...OR ABOUT 35 DEGREES COLDER THAN THE HIGHS WERE
THIS AFTERNOON. IN ADDITION TO THE COLD AIR...WE WILL SEE WRAP
AROUND PRECIP DIP DOWN ABOUT AS FAR SOUTH AS A MADISON TO MILLE LACS
LAKE LINE. FORECAST SOUNDINGS IN THIS AREA ARE ALSO COLD ENOUGH TO
SHOW A RAIN/SLEET MIX DEVELOPING LATE TONIGHT. IN FACT...THE NAM
WOULD SAY THE P-TYPE AT AXN WILL BE ALL SLEET TOMORROW MORNING...SO
DID INTRODUCE A PRECIP MIX INTO THE GRIDS. BESIDE THE PRECIP...WINDS
WILL BE STRONG AS WELL. TOP OF THE CHANNEL MIX DOWN AT MOST SITES IN
MN IS OVER 40 KTS. WE ARE RIGHT ON THE CUSP OF NEEDING A WIND
ADVY...BUT DECIDED TO HOLD OFF ON ONE FOR NOW AND WILL LET THE
SEVERE POTENTIAL PLAY OUT BEFORE HOISTING A WIND ADVY.
FOR MONDAY...THERE IS NO WAY AROUND IT...IT WILL BE A RAW DAY. NAM
HAS H85 TEMPS DROPPING TO BETWEEN -5 AND -8C...WHICH IS BELOW THE
CLIMATOLOGICAL RECORD FOR H85 TEMPS FOR THE DAY AT STC/MPX. THROW IN
THE MOSTLY CLOUDY SKIES...AND HAVE HIGH CONFIDENCE IN HIGHS STAYING
IN THE 40S...WITH HIGHS ONLY IN THE 30S OUT TOWARD AXN. THESE VALUES
WILL BE IN THE 25 TO 35 DEGREES BELOW NORMAL RANGE.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 412 PM CDT SUN MAY 17 2015
THE AFOREMENTIONED STRONG COLD ADVECTION ON MONDAY WILL KEEP THE
LOCAL AREA COOL ON TUESDAY AS WELL WITH HIGHS LIKELY REMAINING IN
THE 50S. THE TROUGH MOVES EAST BY WEDNESDAY AND EAST COAST TROUGH
SHEARS OUT BEFORE ADVANCING OUT OF THE ROCKIES. THEREFORE WE
SHOULD SEE DRY WEATHER AND COOL TO MILD TEMPERATURES THROUGH THE
WEEK...WITH A SLOW WARMING TREND TIME. WE EXPECT TUESDAY AND
WEDNESDAY MORNINGS TO FALL INTO THE 30S ACROSS CENTRAL MN AND WEST
CENTRAL WI...SO WE COULD SEE A LITTLE FROST IF WE MANAGE TO
GET CLEARING AND THE WINDS STAY CALM. WEDNESDAY MORNING HAS A
BETTER CHANCE OF A CALM WIND AND AT LEAST PARTIAL CLEARING. THE
NEXT CHANCE FOR THUNDERSTORMS WILL LIKELY HOLD OFF UNTIL THE
WEEKEND WHEN ANOTHER TROUGH APPROACHES THE REGION FROM THE PLAINS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 700 PM CDT SUN MAY 17 2015
SCATTERED SHOWERS AND WEAK THUNDERSTORMS WILL CONTINUE IN EASTERN
MN THROUGH ABOUT 01-02Z AND ABOUT 04Z IN WESTERN WI. THERE WILL BE
SEVERAL HOURS OF VFR IN MN /LONGER IN WI/ BEFORE AN MVFR STRATUS
DECK MOVES IN LATE THIS EVENING AND TONIGHT AND LINGERS THROUGH
THE DAY TOMORROW. IFR IS POSSIBLE ACROSS PORTIONS OF CENTRAL
MN...BUT MOST OF THE TAF SITES SHOULD REMAIN BETWEEN 1500-2500FT
FOR CLOUD BASES.
KMSP...
THERE ARE A FEW SHOWERS TO THE WEST OF KMSP...WHICH WILL BE IN THE
VICINITY FOR THE NEXT 1-2 HOURS BEFORE THE DRIER AIR TAKES OVER
AND SHUTS DOWN THE PRECIP CHANCES. OTHERWISE...WE HAVE MEDIUM TO
HIGH CONFIDENCE OF 2000-2200FT CEILINGS AT THE AIRPORT BEFORE THE
MONDAY MORNING COMMUTE...BUT WE ARE NOT TOO CONFIDENT THEY WILL BE
BELOW 1700FT. WE SHOULD HAVE A MUCH BETTER IDEA AT THE 06Z AND 09Z
UPDATES.
/OUTLOOK FOR KMSP/
TUE...MVFR CIGS POSSIBLE EARLY. WINDS N AT 10 KTS.
WED...VFR. WINDS N 5 KTS.
THU...VFR. WINDS NNW 5 TO 10 KTS.
FRI...VFR. WINDS VARIABLE 0 TO 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WIND ADVISORY UNTIL 4 AM CDT MONDAY FOR MNZ047-054>056-064-065-
073-074-082-091.
WI...NONE.
&&
$$
SHORT TERM...MPG
LONG TERM...CLF
AVIATION...CLF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
357 PM CDT SAT MAY 16 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 351 PM CDT SAT MAY 16 2015
WATER VAPOR IMAGERY THIS AFTERNOON INDICATES A STRONG UPPER LEVEL
CIRCULATION PUSHING EAST THROUGH NORTHERN NEW MEXICO...WITH
CONVECTIVE INITIATION IMMEDIATELY DOWNSTREAM OF THE WAVE ACROSS
THE TEXAS PANHANDLE. MEANWHILE...A WARM FRONT HAS LIFTED INTO
SOUTHERN MN AND DEW POINTS HAVE RISEN WELL INTO THE 60S.
ADDITIONAL THUNDERSTORM DEVELOPMENT ACROSS WESTERN MN INTO EASTERN
SD WILL CONTINUE AS DESTABILIZATION HAS OCCURRED. A SUBTLE WAVE
ADVANCING NORTH WILL HELP INITIATE STORM DEVELOPMENT IN THIS AREA.
EFFECTIVE BULK SHEAR VALUES OF AROUND 30-40 KNOTS MAY PRODUCE
MULTICELL CLUSTERS WITH ISOLATED EMBEDDED SUPERCELLS CAPABLE OF
PRODUCING ISOLATED SEVERE WEATHER ACROSS WESTERN MN THIS EVENING.
EASTERN MN AND WESTERN WI SHOULD GENERALLY REMAIN DRY THROUGH THE
EVENING...BEFORE SCATTERED SHOWERS AND WEAK THUNDERSTORMS MOVE IN
LATE TONIGHT THROUGH SUNDAY MORNING.
ON SUNDAY...THE AFOREMENTIONED UPPER LEVEL SHORTWAVE WILL ADVANCE
NORTH AND A DEEPENING SURFACE LOW WILL ADVANCE FROM KANSAS
NORTHWARD THROUGH NEBRASKA AND EVENTUALLY INTO EASTERN SOUTH
DAKOTA. WITH A MOIST AND UNSTABLE AIRMASS PRESENT...MUCH BETTER
SHEAR AND SURFACE ENERGY WILL COME TOGETHER THROUGH EARLY
AFTERNOON...ESPECIALLY ACROSS EASTERN MN AND WESTERN WI...WHERE
THE SEVERE WEATHER RISK HAS BEEN UPGRADED TO THE ENHANCED
CATEGORY. 0-6KM EFFECTIVE SHEAR APPROACHING 60 KNOTS COMBINED WITH
BETTER SURFACE HEATING ACROSS THIS AREA WILL ALLOW SURFACE BASED
CAPE VALUES OF 1000-2000 J/KG. CONFIDENCE IS RELATIVELY LOW THOUGH
IN THE SEVERE DEVELOPMENT POTENTIAL DUE TO MORNING CONVECTION AND
ITS POSSIBLE AFFECT ON DESTABILIZATION BY EARLY AFTERNOON. GIVEN
SUFFICIENT HEATING THOUGH...EXPECT BY EARLY AFTERNOON THE
POSSIBILITY OF DISCRETE SUPERCELL THUNDERSTORMS INITIATING IN
EASTERN MN AND WESTERN WI WHICH WOULD BE CAPABLE OF PRODUCING
SEVERE HAIL...WIND...AND A FEW TORNADOES.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 351 PM CDT SAT MAY 16 2015
SFC LOW OVER N-CENTRAL MN WILL HAVE ITS PROGRESS SLOWED AS IT
RUNS INTO HIGHER PRES FROM THE N. MEANWHILE...THE DEEP UPR LVL LOW
WILL THEN RUN ATOP THE SFC LOW...MAKING FOR A DEEPLY STACKED LOW
PRES AREA CENTERED OVER NERN MN COME DAYBREAK MON MRNG. THE BULK
OF THE SHWRS/TSTMS WILL BE IN ERN PORTIONS OF THE WFO MPX CWFA BY
SUN EVE...PARTICULARLY ANYTHING OF A STRONG/SEVERE NATURE...
LEAVING MAINLY RESIDUAL SHOWERS AND ISOLD TSTMS IN THE WAKE OF THE
PASSING CDFNT. WHILE THE FRONTAL PRECIP COVERAGE WANES SUN NIGHT
INTO MON...THE DEEP COLD LOW MOVING OVER THE REGION MAY BRING
ADDITIONAL LIGHT RAIN SHOWERS TO NRN-CENTRAL MN AND NWRN WI DURG
THE DAY ON MON. THIS LOW WILL THEN PULL AWAY FROM THE AREA MON
NIGHT INTO TUE...BEING REPLACED BY SFC HIGH PRES THAT WILL REMAIN
IN PLACE TUE THRU FRI...MAKING FOR A PROLONGED DRY PERIOD FOR THE
REGION. HOWEVER...AT THE SAME TIME...THE NW-SE ORIENTATION OF THE
SFC HIGH COMBINED WITH A LONGWAVE TROF SETTING UP OVER ERN NOAM
WILL ALLOW A PERSISTENT PATH OF MUCH COLDER CANADIAN AIR TO TAKE
RESIDENCE OVER THE REGION THRU AT LEAST THE FIRST HALF OF THE
WEEK. THIS POTENT SURGE OF CAA WILL DROP TEMPS NEARLY 30 DEGREES
FROM SUN INTO MON AS HIGHS ON MON WILL RANGE FROM THE LOWER 40S TO
THE LOWER 50S. TEMPERATURES WILL THEN SLOWLY MODERATE THROUGH THE
REST OF THE WEEK...WITH HIGHS RETURNING TO THE UPPER 60S BY THE
END OF THE WEEK. FROST MAY BE A CONCERN ON MON AND TUE NIGHTS AS
LOWS DIP INTO THE LOW/MID 30S ACROSS PARTS OF CENTRAL MN/WI.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1246 PM CDT SAT MAY 16 2015
CURRENT SCENARIO MAKES FOR A MESSY AVIATION FORECAST FOR THE AREA.
A SURFACE LOW IS PUSHING INTO WESTERN SOUTH DAKOTA FROM THE
WEST...WITH A WARM FRONT EXTENDING EAST AND DEW POINTS IN THE MID
60S SURGING NORTHWARD INTO SOUTHERN MN. DEW POINT DEPRESSIONS WILL
REMAIN JUST A COUPLE DEGREES...AND LOW LEVEL LCL`S SHOULD REMAIN
IN PLACE. SO...EXPECTING WIDESPREAD MVFR TO HOLD FOR THE MOST PART
WITH A FEW PERIODS OF SCATTERING OCCURRING THIS AFTERNOON. LATE
THIS AFTERNOON...A LINE OF THUNDERSTORMS IS EXPECTED TO DEVELOP
AND PUSH EAST INTO WESTERN MN AND CONTINUE NORTHEAST THROUGH THE
EVENING. RWF/STC/AXN MAY ALL BE DIRECTLY IMPACTED BY THIS
LINE...BUT MSP MAY BE ON THE SOUTHERN PERIPHERY OF THESE
STORMS...WILL BE SOMETHING TO MONITOR. AS THE LOW DEEPENS IN SOUTH
DAKOTA TONIGHT AND TOMORROW MORNING...WE`LL REMAIN IN UNSTABLE AIR
AND MORE THUNDERSTORM DEVELOPMENT IS EXPECTED TOMORROW MORNING.
KMSP...BEST CHANCE FOR THUNDER TONIGHT WILL BE FROM 03Z TO
06Z...HOWEVER THE HRRR INDICATES THE POSSIBILITY THAT THE
THUNDERSTORM CLUSTER MOVING THROUGH WESTERN MN THIS AFTERNOON MAY
SLIDE JUST NORTH OF MSP...BUT IF IT DOES STILL EXPECT OTHER SPOTTY
THUNDERSTORM DEVELOPMENT LATE TONIGHT. FOR TOMORROW
AFTERNOON...STRONG THUNDERSTORMS LOOK TO DEVELOP AND MOVE THROUGH
FROM ROUGHLY 20-23Z.
/OUTLOOK FOR KMSP/
MON...MVFR CIGS. SCT -SHRA. WINDS NW AT 15-25 KTS.
TUE...MVFR CIGS EARLY. WINDS N AT 10 KTS.
WED...VFR. WINDS NNE 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...SPD
LONG TERM...JPC/CLF
AVIATION...SPD
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
104 PM CDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 406 AM CDT SAT MAY 16 2015
VERY LOW CONFIDENCE IN AREAL COVERAGE OF TSRA/SHRA TODAY...AT LEAST
THRU 18Z AS CAMS AND LOCAL WRF MODELS HAVE NO INDICATION OF CURRENT
CONVECTION EARLY THIS MORNING AND THE EVOLUTION OF THE CONVECTION
THRU NOON. ALTHOUGH SHRA/TSRA HAVE DEVELOPED AFT 7Z ALONG THE
ADVANCING WARM FRONT THAT WAS IN NORTHERN IOWA....THE MORE
CONCENTRATED AREA OF SHRA/TSRA WAS ALONG A STRONGER SHRTWV ACROSS
NE/SD WHICH SHOULD BE THE MAIN ACTION IN SW/WC MN DURING THE
MORNING. THE LATEST HRRR AS OF THE 6Z MODEL RUN DOES HAVE SOME
SUPPORT OF SHRA/TSRA MOVING INTO FAR SW/WC MN BETWEEN 12-15Z WITH
THE ACTIVITY IN NE/SD. IT THEN HAS THIS ACTIVITY DISSIPATING AS IT
MOVES TO THE NE ACROSS SOUTHERN/CENTRAL MN BY NOON. HAVE USED THIS
SCENARIO WITH MORNING POPS/WX GRIDS. THIS AFTN/EVENING IS MORE
RELATED TO AFTN HEATING AND THE DESTABILIZATION OF THE ATMOSPHERE
AND ANY LEFTOVER BOUNDARIES FROM EARLIER CONVECTION...WHICH WILL
LEAD TO WIDELY SCATTERED TSRA THIS AFTN. THE MAIN SHOW SHOULD HOLD
OFF UNTIL LATE AFTN/EVENING AS THE NEXT STRONG SHRTWV MOVES NE
ACROSS THE PLAINS AND INTO THE UPPER MIDWEST.
SEVERE WX PARAMETERS DO SUPPORT ISOLD SVR STORMS BY LATE
AFTN/EVENING AS SHEAR VALUES AND INSTABILITY MAXIMIZE. DEPENDING
UPON THE AMOUNT OF INSTABILITY BASED ON CLOUD COVER AND SFC
HEATING...WILL DETERMINE THE AREAL EXTENT OF THE SVR STORMS. BY THE
MID/LATE EVENING...ANY SVR STORMS WILL BE ELEVATED WHICH LEADS TO
MORE MARGINAL SVR HAIL THEN ANY OTHER SVR THREAT. WILL NEED TO
MONITOR THE EVOLUTION OF STORMS ACROSS THE PLAINS LATE TONIGHT AND
SEE IF ANY EVOLVE INTO A BOW ECHO AND MOVE NE ACROSS THE UPPER
MIDWEST. SEE THE LATEST SPC DAY1/DAY2 FOR MORE INFORMATION.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 406 AM CDT SAT MAY 16 2015
THE LONG TERM PERIOD WILL START OFF ON AN ACTIVE NOTE...WITH A
SUB-995MB LOW PROGGED TO BE NEARING THE SOUTHWEST CORNER OF
MINNESOTA AT DAYBREAK SUNDAY. STRONG LLVL MOISTURE
TRANSPORT/CONVERGENCE AHEAD OF THE TROUGH WILL EXPAND INTO THE
FORECAST AREA BY DAYBREAK SUNDAY...AND GENERATE WIDESPREAD SHOWER
AND THUNDERSTORM ACTIVITY THROUGH THE MID MORNING HOURS. SAID
ACTIVITY WILL LIFT NORTH AND EAST OF THE AREA BY EARLY AFTERNOON.
THE BREAK FROM CONVECTION SHOULD BE BRIEF...AS THE MID/UPPER LOW
PASSES OVERHEAD AT PEAK DAYTIME HEATING. WHILE CONVECTIVE DEBRIS
MAY LIMIT THE POTENTIAL FOR DESTABILIZATION DURING THE
AFTERNOON...STEEP MID LEVEL LAPSE RATES PROVIDED BY THE MID/UPPER
LOW WILL RESULT...AND THEREFORE YIELD A THREAT FOR HAIL. WHILE
COVERAGE/INTENSITY OF STORMS MAY BE MINIMIZED GIVEN THE SYSTEM
WILL BE IN ITS OCCLUSION/WEAKENING PHASE...EFFECTIVE SHEAR VALUES
APPEAR ADEQUATE FOR AT LEAST A FEW STRONG TO SEVERE STORMS ON
SUNDAY AFTERNOON.
THE LOW TAKES ITS TIME GETTING OUT OF THE AREA...EVENTUALLY
REACHING THE UP OF MICHIGAN ON MONDAY MORNING. EXPECTED TO SEE
LIGHT WRAP-AROUND /SCATTERED/ SHOWERS LINGERING ACROSS CENTRAL
MN/WI THROUGH MONDAY.
BEHIND THE TROUGH...BROAD HIGH PRESSURE BUILDS INTO THE DAKOTAS
AND MN ON TUESDAY...AND THEN SPRAWLS OUT ACROSS THE NORTH CENTRAL
CONUS THROUGH THE WEEK. THIS WILL MAKE FOR A DRY STRETCH...WITH NO
ADDITIONAL MEASURABLE PRECIPITATION EXPECTED FROM TUESDAY THROUGH
FRIDAY. IT WILL ALSO YIELD COOL TEMPERATURES...WITH HIGHS IN THE
60S AND LOWS IN THE 30S AND 40S. FROST MAY BE A CONCERN ON MONDAY
NIGHT AND TUESDAY NIGHT...AS LOWS DIP INTO THE LOW/MID 30S ACROSS
PARTS OF CENTRAL MN/WI.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1246 PM CDT SAT MAY 16 2015
CURRENT SCENARIO MAKES FOR A MESSY AVIATION FORECAST FOR THE AREA.
A SURFACE LOW IS PUSHING INTO WESTERN SOUTH DAKOTA FROM THE
WEST...WITH A WARM FRONT EXTENDING EAST AND DEW POINTS IN THE MID
60S SURGING NORTHWARD INTO SOUTHERN MN. DEW POINT DEPRESSIONS WILL
REMAIN JUST A COUPLE DEGREES...AND LOW LEVEL LCL`S SHOUDL REMAIN
IN PLACE. SO...EXPECTING WIDESPREAD MVFR TO HOLD FOR THE MOST PART
WITH A FEW PERIODS OF SCATTERING OCCURRING THIS AFTERNOON. LATE
THIS AFTERNOON...A LINE OF THUNDERSTORMS IS EXPECTED TO DEVELOP
AND PUSH EAST INTO WESTERN MN AND CONTINUE NORTHEAST THROUGH THE
EVENING. RWF/STC/AXN MAY ALL BE DRIECTLY IMPACTED BY THIS
LINE...BUT MSP MAY BE ONTHE SOUTHERN PERIPHERY OF THESE
STORMS...WILL BE SOMETHING TO MONITOR. AS THE LOW DEEPENS IN SOUTH
DAKOTA TONIGHT AND TOMORROW MORNING...WE`LL REMAIN IN UNSTABLE AIR
AND MORE THUNDERSTORM DEVELOPMENT IS EXPECTED TOMORROW MORNING.
KMSP...BEST CHANCE FOR THUNDER TONIGHT WILL BE FROM 03Z TO
06Z...HOWEVER THE HRRR INDICATES THE POSSIBLITY THAT THE
THUNDERSTORM CLUSTER MOVING THROUGH WESTERN MN THIS AFTERNOON MAY
SLIDE JUST NORTH OF MSP...BUT IF IT DOES STILL EXPECT OTHER SPOTTY
THUNDERSTORM DEVELOPMENT LATE TONIGHT. FOR TOMORROW
AFTERNOON...STRONG THUNDERSTORMS LOOK TO DEVELOP AND MOVE THROUGH
FROM ROUGHLY 20-23Z.
/OUTLOOK FOR KMSP/
MON...MVFR CIGS. SCT -SHRA. WINDS NW AT 15-25 KTS.
TUE...MVFR CIGS EARLY. WINDS N AT 10 KTS.
WED...VFR. WINDS NNE 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JLT
LONG TERM...LS
AVIATION...SPD
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
546 AM CDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 406 AM CDT SAT MAY 16 2015
VERY LOW CONFIDENCE IN AREAL COVERAGE OF TSRA/SHRA TODAY...AT LEAST
THRU 18Z AS CAMS AND LOCAL WRF MODELS HAVE NO INDICATION OF CURRENT
CONVECTION EARLY THIS MORNING AND THE EVOLUTION OF THE CONVECTION
THRU NOON. ALTHOUGH SHRA/TSRA HAVE DEVELOPED AFT 7Z ALONG THE
ADVANCING WARM FRONT THAT WAS IN NORTHERN IOWA....THE MORE
CONCENTRATED AREA OF SHRA/TSRA WAS ALONG A STRONGER SHRTWV ACROSS
NE/SD WHICH SHOULD BE THE MAIN ACTION IN SW/WC MN DURING THE
MORNING. THE LATEST HRRR AS OF THE 6Z MODEL RUN DOES HAVE SOME
SUPPORT OF SHRA/TSRA MOVING INTO FAR SW/WC MN BETWEEN 12-15Z WITH
THE ACTIVITY IN NE/SD. IT THEN HAS THIS ACTIVITY DISSIPATING AS IT
MOVES TO THE NE ACROSS SOUTHERN/CENTRAL MN BY NOON. HAVE USED THIS
SCENARIO WITH MORNING POPS/WX GRIDS. THIS AFTN/EVENING IS MORE
RELATED TO AFTN HEATING AND THE DESTABILIZATION OF THE ATMOSPHERE
AND ANY LEFTOVER BOUNDARIES FROM EARLIER CONVECTION...WHICH WILL
LEAD TO WIDELY SCATTERED TSRA THIS AFTN. THE MAIN SHOW SHOULD HOLD
OFF UNTIL LATE AFTN/EVENING AS THE NEXT STRONG SHRTWV MOVES NE
ACROSS THE PLAINS AND INTO THE UPPER MIDWEST.
SEVERE WX PARAMETERS DO SUPPORT ISOLD SVR STORMS BY LATE
AFTN/EVENING AS SHEAR VALUES AND INSTABILITY MAXIMIZE. DEPENDING
UPON THE AMOUNT OF INSTABILITY BASED ON CLOUD COVER AND SFC
HEATING...WILL DETERMINE THE AREAL EXTENT OF THE SVR STORMS. BY THE
MID/LATE EVENING...ANY SVR STORMS WILL BE ELEVATED WHICH LEADS TO
MORE MARGINAL SVR HAIL THEN ANY OTHER SVR THREAT. WILL NEED TO
MONITOR THE EVOLUTION OF STORMS ACROSS THE PLAINS LATE TONIGHT AND
SEE IF ANY EVOLVE INTO A BOW ECHO AND MOVE NE ACROSS THE UPPER
MIDWEST. SEE THE LATEST SPC DAY1/DAY2 FOR MORE INFORMATION.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 406 AM CDT SAT MAY 16 2015
THE LONG TERM PERIOD WILL START OFF ON AN ACTIVE NOTE...WITH A
SUB-995MB LOW PROGGED TO BE NEARING THE SOUTHWEST CORNER OF
MINNESOTA AT DAYBREAK SUNDAY. STRONG LLVL MOISTURE
TRANSPORT/CONVERGENCE AHEAD OF THE TROUGH WILL EXPAND INTO THE
FORECAST AREA BY DAYBREAK SUNDAY...AND GENERATE WIDESPREAD SHOWER
AND THUNDERSTORM ACTIVITY THROUGH THE MID MORNING HOURS. SAID
ACTIVITY WILL LIFT NORTH AND EAST OF THE AREA BY EARLY AFTERNOON.
THE BREAK FROM CONVECTION SHOULD BE BRIEF...AS THE MID/UPPER LOW
PASSES OVERHEAD AT PEAK DAYTIME HEATING. WHILE CONVECTIVE DEBRIS
MAY LIMIT THE POTENTIAL FOR DESTABILIZATION DURING THE
AFTERNOON...STEEP MID LEVEL LAPSE RATES PROVIDED BY THE MID/UPPER
LOW WILL RESULT...AND THEREFORE YIELD A THREAT FOR HAIL. WHILE
COVERAGE/INTENSITY OF STORMS MAY BE MINIMIZED GIVEN THE SYSTEM
WILL BE IN ITS OCCLUSION/WEAKENING PHASE...EFFECTIVE SHEAR VALUES
APPEAR ADEQUATE FOR AT LEAST A FEW STRONG TO SEVERE STORMS ON
SUNDAY AFTERNOON.
THE LOW TAKES ITS TIME GETTING OUT OF THE AREA...EVENTUALLY
REACHING THE UP OF MICHIGAN ON MONDAY MORNING. EXPECTED TO SEE
LIGHT WRAP-AROUND /SCATTERED/ SHOWERS LINGERING ACROSS CENTRAL
MN/WI THROUGH MONDAY.
BEHIND THE TROUGH...BROAD HIGH PRESSURE BUILDS INTO THE DAKOTAS
AND MN ON TUESDAY...AND THEN SPRAWLS OUT ACROSS THE NORTH CENTRAL
CONUS THROUGH THE WEEK. THIS WILL MAKE FOR A DRY STRETCH...WITH NO
ADDITIONAL MEASURABLE PRECIPITATION EXPECTED FROM TUESDAY THROUGH
FRIDAY. IT WILL ALSO YIELD COOL TEMPERATURES...WITH HIGHS IN THE
60S AND LOWS IN THE 30S AND 40S. FROST MAY BE A CONCERN ON MONDAY
NIGHT AND TUESDAY NIGHT...AS LOWS DIP INTO THE LOW/MID 30S ACROSS
PARTS OF CENTRAL MN/WI.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 540 AM CDT SAT MAY 16 2015
HIGH CONFIDENCE THAT THE FIRST 6 HRS WILL BE THUNDERSTORM FREE
WITH THE EXCEPTION OF KRWF/KAXN WHERE ISOLD STORMS WILL BE
POSSIBLE BUT NOT ENOUGH TO WARRANT MORE THAN VCTS. MVFR CIGS WILL
SPREAD NORTHWARD ACROSS CENTRAL MN...WITH VFR CONDS ELSEWHERE THRU
15Z. AFT 18Z...CONFIDENCE IS MUCH LOWER ON SHRA/TSRA
COVERAGE...ESPECIALLY IN EASTERN MN/WC WI WHERE TSRA/SHRA MAY NOT
OCCUR UNTIL LATER THIS EVENING. HIGHER CONFIDENCE THAT WC/SW MN
WILL HAVE SHRA/TSRA WITH LOWER VSBYS/CIGS BY THIS EVENING. WINDS
WILL INCREASE FROM THE ESE/SE TODAY...WITH SOME GUSTS DURING THE
AFTN.
KMSP...
CONFIDENCE IS HIGH THAT NO TSRA/SHRA WILL OCCUR IN THE FIRST 6
HRS. CONFIDENCE DECREASES BY MID/LATE AFTN BUT CIGS SHOULD REMAIN
VFR. BEST CHC OF TSRA WILL OCCUR LATER THIS EVENING/OVERNIGHT.
WINDS WILL SHIFT TO THE SE AND INCREASE DURING THE MORNING.
/OUTLOOK FOR KMSP/
MON...MVFR CIGS. SCT -SHRA. WINDS NW AT 15-25 KTS.
TUE...MVFR CIGS EARLY. WINDS N AT 10 KTS.
WED...VFR. WINDS NNE 5 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JLT
LONG TERM...LS
AVIATION...JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
406 AM CDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 406 AM CDT SAT MAY 16 2015
VERY LOW CONFIDENCE IN AREAL COVERAGE OF TSRA/SHRA TODAY...AT LEAST
THRU 18Z AS CAMS AND LOCAL WRF MODELS HAVE NO INDICATION OF CURRENT
CONVECTION EARLY THIS MORNING AND THE EVOLUTION OF THE CONVECTION
THRU NOON. ALTHOUGH SHRA/TSRA HAVE DEVELOPED AFT 7Z ALONG THE
ADVANCING WARM FRONT THAT WAS IN NORTHERN IOWA....THE MORE
CONCENTRATED AREA OF SHRA/TSRA WAS ALONG A STRONGER SHRTWV ACROSS
NE/SD WHICH SHOULD BE THE MAIN ACTION IN SW/WC MN DURING THE
MORNING. THE LATEST HRRR AS OF THE 6Z MODEL RUN DOES HAVE SOME
SUPPORT OF SHRA/TSRA MOVING INTO FAR SW/WC MN BETWEEN 12-15Z WITH
THE ACTIVITY IN NE/SD. IT THEN HAS THIS ACTIVITY DISSIPATING AS IT
MOVES TO THE NE ACROSS SOUTHERN/CENTRAL MN BY NOON. HAVE USED THIS
SCENARIO WITH MORNING POPS/WX GRIDS. THIS AFTN/EVENING IS MORE
RELATED TO AFTN HEATING AND THE DESTABILIZATION OF THE ATMOSPHERE
AND ANY LEFTOVER BOUNDARIES FROM EARLIER CONVECTION...WHICH WILL
LEAD TO WIDELY SCATTERED TSRA THIS AFTN. THE MAIN SHOW SHOULD HOLD
OFF UNTIL LATE AFTN/EVENING AS THE NEXT STRONG SHRTWV MOVES NE
ACROSS THE PLAINS AND INTO THE UPPER MIDWEST.
SEVERE WX PARAMETERS DO SUPPORT ISOLD SVR STORMS BY LATE
AFTN/EVENING AS SHEAR VALUES AND INSTABILITY MAXIMIZE. DEPENDING
UPON THE AMOUNT OF INSTABILITY BASED ON CLOUD COVER AND SFC
HEATING...WILL DETERMINE THE AREAL EXTENT OF THE SVR STORMS. BY THE
MID/LATE EVENING...ANY SVR STORMS WILL BE ELEVATED WHICH LEADS TO
MORE MARGINAL SVR HAIL THEN ANY OTHER SVR THREAT. WILL NEED TO
MONITOR THE EVOLUTION OF STORMS ACROSS THE PLAINS LATE TONIGHT AND
SEE IF ANY EVOLVE INTO A BOW ECHO AND MOVE NE ACROSS THE UPPER
MIDWEST. SEE THE LATEST SPC DAY1/DAY2 FOR MORE INFORMATION.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 406 AM CDT SAT MAY 16 2015
THE LONG TERM PERIOD WILL START OFF ON AN ACTIVE NOTE...WITH A
SUB-995MB LOW PROGGED TO BE NEARING THE SOUTHWEST CORNER OF
MINNESOTA AT DAYBREAK SUNDAY. STRONG LLVL MOISTURE
TRANSPORT/CONVERGENCE AHEAD OF THE TROUGH WILL EXPAND INTO THE
FORECAST AREA BY DAYBREAK SUNDAY...AND GENERATE WIDESPREAD SHOWER
AND THUNDERSTORM ACTIVITY THROUGH THE MID MORNING HOURS. SAID
ACTIVITY WILL LIFT NORTH AND EAST OF THE AREA BY EARLY AFTERNOON.
THE BREAK FROM CONVECTION SHOULD BE BRIEF...AS THE MID/UPPER LOW
PASSES OVERHEAD AT PEAK DAYTIME HEATING. WHILE CONVECTIVE DEBRIS
MAY LIMIT THE POTENTIAL FOR DESTABILIZATION DURING THE
AFTERNOON...STEEP MID LEVEL LAPSE RATES PROVIDED BY THE MID/UPPER
LOW WILL RESULT...AND THEREFORE YIELD A THREAT FOR HAIL. WHILE
COVERAGE/INTENSITY OF STORMS MAY BE MINIMIZED GIVEN THE SYSTEM
WILL BE IN ITS OCCLUSION/WEAKENING PHASE...EFFECTIVE SHEAR VALUES
APPEAR ADEQUATE FOR AT LEAST A FEW STRONG TO SEVERE STORMS ON
SUNDAY AFTERNOON.
THE LOW TAKES ITS TIME GETTING OUT OF THE AREA...EVENTUALLY
REACHING THE UP OF MICHIGAN ON MONDAY MORNING. EXPECTED TO SEE
LIGHT WRAP-AROUND /SCATTERED/ SHOWERS LINGERING ACROSS CENTRAL
MN/WI THROUGH MONDAY.
BEHIND THE TROUGH...BROAD HIGH PRESSURE BUILDS INTO THE DAKOTAS
AND MN ON TUESDAY...AND THEN SPRAWLS OUT ACROSS THE NORTH CENTRAL
CONUS THROUGH THE WEEK. THIS WILL MAKE FOR A DRY STRETCH...WITH NO
ADDITIONAL MEASURABLE PRECIPITATION EXPECTED FROM TUESDAY THROUGH
FRIDAY. IT WILL ALSO YIELD COOL TEMPERATURES...WITH HIGHS IN THE
60S AND LOWS IN THE 30S AND 40S. FROST MAY BE A CONCERN ON MONDAY
NIGHT AND TUESDAY NIGHT...AS LOWS DIP INTO THE LOW/MID 30S ACROSS
PARTS OF CENTRAL MN/WI.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1105 PM CDT FRI MAY 15 2015
SOME LOW CLOUDS REMAIN ACROSS SOUTHERN MN AND WESTERN WI AS A
WARM FRONT CONTINUES TO MOVE NORTH THROUGH IOWA. AREAS OF MVFR
CIGS ARE POSSIBLE OVERNIGHT THROUGH SATURDAY MORNING...ESPECIALLY
FROM 12Z-15Z SATURDAY AS THE FRONT MOVES INTO SOUTHERN MN.
SCATTERED SHOWERS AND THUNDERSTORMS SHOULD DEVELOP OVER WESTERN MN
SATURDAY MORNING...AND SPREAD INTO CENTRAL AND EASTERN MN BETWEEN
18Z-00Z. BRIEF PERIODS OF IFR CONDITIONS ARE POSSIBLE IN ANY
STORMS THAT DEVELOP...AS WELL AS GUSTY WINDS AND A CHANCE OF HAIL
IN THE STRONGEST STORMS...ESPECIALLY AT AXN AND RWF DURING
SATURDAY AFTERNOON AND EVENING.
KMSP...SCATTERED/BROKEN AREAS OF LOW CLOUDS WILL CONTINUE
OVERNIGHT...AND MVFR CIGS ARE POSSIBLE BETWEEN 12Z-15Z AHEAD OF A
WARM FRONT MOVING THROUGH SOUTHERN MN. CIGS SHOULD REBOUND LATER
SATURDAY MORNING...BUT THUNDERSTORM CHANCES WILL INCREASE DURING
THE AFTERNOON. PERIODS OF IFR CONDITIONS ARE POSSIBLE IN THE
THUNDERSTORMS...AND WILL BECOME MORE LIKELY AFTER 00Z AS STORM
CHANCES INCREASE.
/OUTLOOK FOR KMSP/
SUN...VFR WITH SCATTERED IFR/TSRA. WINDS S AT 15-25 KTS.
MON...VFR. WINDS NW AT 15-25 KTS.
TUE...VFR. WINDS N AT 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...JLT
LONG TERM...LS
AVIATION...ADL
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1018 AM CDT SAT MAY 16 2015
.UPDATE...WIDESPREAD CLOUD COVER PREVALENT OVER THE REGION THIS
MORNING SHOULD CONTINUE TO SLOW THE WARMING PROCESS. LATEST HRRR
APPEARS TO WARM THE REGION UP A LITTLE TOO FAST COMPARED TO LATEST
OBSERVATIONS. CURRENT FORECAST MAX TEMPS IN THE MID 80S STILL LOOKS
ATTAINABLE...JUST MAY TAKE A LITTLE LONGER TO ACHIEVE. AREA SOUNDINGS
SHOW DEEP MOISTURE IN PLACE THIS MORNING WITH PW VALUES RUNNING CLOSE
TO 1.75 INCHES. BEST LOW LEVEL MOISTURE REMAINS OVER THE
SOUTH...WHILE ON THE JAN SOUNDING THIS MORNING A DRY LAYER EXISTED
FROM 800-950 MB. LOOKING AT THE HRRR DATA...THIS DRY LAYER MAY SERVE
TO SLOW CONVECTIVE INITIATION UNTIL TEMPS CAN REACH INTO THE LOWER
80S. CURRENT FORECAST PACKAGE APPEARS ON TRACK./26/
&&
.AVIATION...UNDER SOUTHERLY MOIST FLOW EXPECT LINGERING IFR CEILINGS
IN THE SOUTHWEST TO LIFT UP TO MVFR BY 17Z. SHRA/TSRA
CHANCES(IFR/MVFR CONDITIONS) WILL BE LIKELY FOR THE WHOLE CWA FOR
THIS AFTERNOON AS AN UPPER LEVEL DISTURBANCE APPROACHES FROM THE
WEST. THE DISTURBANCE WILL COMBINE WITH DAYTIME HEATING TO BRING GOOD
PCPN COVERAGE. SO INTERESTS SHOULD PLAN FOR TSRA AT ALL SITES FOR
THIS AFTERNOON. SHRA/TSRA WILL DIMINISH EARLY THIS EVNG WITH A FEW
SHRA LINGERING OVERNIGHT. LATEST GUIDANCE SUGGEST WIDESPREAD IFR
STRATUS WILL DEVELOP LATE TONIGHT INTO EARLY SUNDAY MRNG. /17/EC/
&&
.PREV DISCUSSION... /ISSUED 436 AM CDT SAT MAY 16 2015/
DISCUSSION...
TODAY THROUGH SUNDAY NIGHT...
FORECAST THINKING REMAINS THE SAME FOR TODAY AS A PERSISTENT TROUGH
TO RIDGE PATTERN OVER THE CENTRAL/EASTERN CONUS CONTINUES TO PROMOTE
VERY MOIST SOUTHERLY FLOW JUXTAPOSED BY DISTURBED SOUTHWESTERLY FLOW
ALOFT. LATEST HIGH-RES GUIDANCE CONTINUE TO SUGGEST WEATHER TRENDS
SIMILAR TO YESTERDAY. SHOWER/THUNDERSTORM ACTIVITY WILL REGENERATE
WITH DAYTIME HEATING AHEAD OF ANOTHER UPPER LEVEL SHORTWAVE TROUGH...
AND MAY BECOME FAIRLY WIDESPREAD IN THE AFTERNOON. 20-30KTS OF
LOW/MID LEVEL FLOW WILL SUPPORT SOME MULTI-CELL STORM ORGANIZATION
WITH STEEP LOW LEVEL LAPSE RATES AND FLOW SUPPORTIVE OF STRONG TO
PERHAPS EVEN A FEW SEVERE WIND GUSTS. THIS WILL ESPECIALLY BE THE
CASE WHERE STORMS ANCHOR ALONG OUTFLOW BOUNDARIES DURING PEAK
HEATING...AND WHERE THE BOUNDARIES ARE ORIENTED MORE WNW-ESE AND
ORTHOGONAL TO SSW LOW LEVEL SHEAR VECTORS. EXPECT ANY SEVERE WEATHER
OCCURRENCES TO BE VERY ISOLATED AND WILL KEEP THE MENTION OUT OF THE
HAZARDOUS WEATHER PRODUCTS FOR NOW.
GIVEN SUBSTANTIAL OUTFLOW MOTIONS AND HIGH COVERAGE OF PRECIPITATION
AGAIN TODAY...HAVE FOLLOWED HIGHER GUIDANCE POPS. CONVECTION WILL
DIMINISH EARLY IN THE EVENING AND DO NOT EXPECT IT TO PERSIST AS LONG
AS IT DID LAST NIGHT. SUNDAY WILL SEE SOMEWHAT OF A REPEAT OF THIS
PATTERN...BUT BETTER CONVECTIVE PRECIPITATION COVERAGE MAY HOLD OFF
UNTIL A STRONGER BOUNDARY APPROACHES LATE SUNDAY NIGHT IN NORTHWEST
PORTIONS OF THE ARKLAMISS. /EC/
MONDAY INTO SATURDAY...THE MED RANGE/LONG TERM LOOKS
TO REMAIN A BIT ON THE ACTIVE SIDE WRT PRECIP POTENTIAL. DEEP
MOISTURE (PWS 1.6-1.8 IN) WILL RESIDE OVER THE REGION THROUGH MUCH
OF THE PERIOD WITH THE PRESENCE OF A WEAK SFC BOUNDARY IN THE
VICINITY THROUGH THIS TIME AS WELL. ADDITIONALLY...GLOBAL MODELS
CONTINUE TO SHOW SEVERAL DISTURBANCES INTERACTING WITH THE MOISTURE
AND BOUNDARY TO HELP TRIGGER SHOWERS/STORMS. AT THIS TIME...THE MOST
PREVALENT WAVE LOOKS TO IMPACT THE CWA ON MON. IN RESPONSE TO
THIS...40-70% POPS ARE IN PLACE TO CAPTURE THE POTENTIAL. THE
OVERALL EVOLUTION OF ACTIVITY ON MON IS NOT CLEAR AS SOME OF THE
AREA COULD SEE PRECIP EARLY IN THE DAY FROM SOME LEFT OVER STORMS
MOVING OUT OF AR WITH OTHER SOLUTIONS SHOWING ACTIVITY WAITING UNTIL
THE AFTERNOON. THERE IS SOME POTENTIAL FOR STRONGER STORMS AS BETTER
MID LEVEL LAPSE RATES WILL BE IN PLACE ALONG WITH HIGHER DEEP LAYER
SHEAR. OVERALL...HOW THINGS EVOLVE AND TIMING WILL PLAY A KEY ROLE
AND WITH UNCERTAINTY IN THOSE...WILL NOT MENTION ANYTHING IN THE HWO
AT THIS TIME...BUT WILL KEEP A CLOSE EYE ON TRENDS.
LINGERING PRECIP CHANCES WILL EXIST THROUGH THE REMAINDER OF THE
WEEK WITH AT LEAST ONE OPPORTUNITY FOR A DECENT SHOT AT MORE PRECIP.
AT THIS TIME...THU INTO THU NGT MAY BE THAT PERIOD AS MOST MODELS
SHOW ANOTHER DECENT WAVE AND GOOD QPF SIGNAL.
AS FOR TEMPS...PERSISTENCE TYPE FORECAST IS IN ORDER AND THE BLENDED
GUID SEEMS TO BE ON TARGET. EXPECT TEMPS TO REMAIN JUST A BIT WARMER
THAN CLIMO READINGS WITH HIGHS ROUGHLY 85-90 AND LOWS 65-70.
SOUTHERN AREAS WILL LIKELY BE ON THE WARMER SIDE OF THOSE RANGES AS
THEY WILL BE FURTHER REMOVED FROM THE LINGERING SFC BOUNDARY. /CME/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 86 70 87 70 / 62 33 43 32
MERIDIAN 84 69 86 68 / 70 35 44 29
VICKSBURG 86 71 88 72 / 60 26 41 32
HATTIESBURG 85 70 87 70 / 70 45 41 20
NATCHEZ 85 72 87 72 / 59 29 40 23
GREENVILLE 85 71 86 71 / 64 34 59 50
GREENWOOD 85 70 87 70 / 69 34 49 49
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1201 AM CDT Sat May 16 2015
.SHORT TERM...(This Evening through Saturday)
Issued at 222 PM CDT FRI MAY 15 2015
A weak impulse is currently moving across the Missouri Ozarks and
lifting northeastward. Scattered convection has developed ahead of
the impulse across central Missouri and the eastern Ozarks where
instability is better. This convection will continue to move
northward. There appears to be a little subsidence behind the
exiting upper level impulse. Additional isolated to widely scattered
convection is possible elsewhere through the evening hours where the
sun is able to add some instability but it will be limited. Short
range models like the HRRR and RUC13 keep most of the convection
redevelopment towards central Missouri this evening.
Later this evening...for the most part the weather should be fairly
quiet. Will mention the possibility of some patchy fog near large
lakes and river valleys by sunrise in the morning. Forecast cape for
tomorrow approach 2500 J/KG but the deep shear will be limited
around 20 to 25 knots for most of the day over the Ozarks. The
better dynamics will be just to our west across Kansas and Oklahoma
for severe convection. Scattered convection will develop around the
Missouri Ozarks by midday to afternoon on Saturday with the best
potential over south central Missouri.
Models indicate that the leftover severe convection that develops
across Kansas and Oklahoma will move into southeast Kansas and
extreme western Missouri late Saturday evening and overnight. There
is a slight risk for severe weather Saturday evening for these areas
with the main threat being damaging wind gusts and large hail.
MUCape will be between 1500 to 2000 J/KG with Bulk shear values
increasing to 40 knots by Saturday evening over southeast Kansas
and western Missouri. Line segments and clusters of convection is
expected moving eastward from Kansas and Oklahoma into the western
Missouri Ozarks. Total QPF this weekend is expected on average
between 0.5 to 1.0 of an inch.
.LONG TERM...(Sunday through Friday)
Issued at 222 PM CDT FRI MAY 15 2015
The main upper level support and energy moves away from the area on
Sunday and Sunday night. Models indicate the best potential for
additional convection develop on Sunday afternoon and evening will
be south and east of I-44 across south central Missouri. There
is a very limited potential for a couple strong storms over south
central Missouri Sunday evening. A cold front finally makes some
progress into the area by Monday. There will be a chance for
showers and storms across south central Missouri before the front
clears through the area.
Cool and drier air will move in for Monday night through Tuesday
evening. Temperatures will be below average. The weather pattern
becomes unsettled again by the middle and end of next week.
Another broad trough develops across the western U.S. and weak
shortwaves and impulses will move across the central Plains and
Midwest starting Wednesday through Friday with scattered rain
chances and thunderstorms.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday Night)
Issued at 1148 PM CDT FRI MAY 15 2015
An area of showers and perhaps a few thunderstorms will spread
north into portions of southern Missouri late tonight and early
Saturday morning. MVFR ceilings will also accompany this
activity...especially around Branson. There is even some potential
for IFR ceilings across south-central Missouri. Confidence in this
scenario remains low enough to preclude IFR from the TAFs.
Additional scattered thunderstorm development is then expected
from late Saturday morning into early Saturday afternoon across
western Missouri. MVFR and brief IFR conditions can be expected
with any thunderstorms. Outside of thunderstorms, surface winds
will increase out of the south on Saturday and will become gusty.
Yet another round of thunderstorms will then be possible across
western Missouri late Saturday evening towards the end of the TAF
period.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Griffin
LONG TERM...Griffin
AVIATION...Schaumann
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
333 PM CDT SAT MAY 16 2015
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 332 PM CDT SAT MAY 16 2015
SEVERE POTENTIAL TONIGHT REMAINS THE PRIMARY FORECAST CONCERN.
SCATTERED CONVECTION SUNDAY FOLLOWED BY COOLER TEMPERATURES TO BEGIN
THE WORK WEEK ARE SECONDARY CONCERNS.
18Z SOUNDING AT KOAX SHOWED ALMOST 1500 J/KG OF SURFACE-BASED
CAPE...WHICH IS MUCH LOWER THAN THE 2500 J/KG SHOWN BY OPERATIONAL
RAP ANALYSIS OBSERVED ON SPC MESOANALYSIS PAGE. SOUNDING ALSO SHOWED
ALMOST 50 J/KG OF CONVECTIVE INHIBITION. HOWEVER AXIS OF HIGHEST
CAPE NEAR OUR CWA DEPICTED BY RAP STILL LOOKS GOOD STRETCHING FROM
EASTERN SOUTH DAKOTA INTO WESTERN IOWA WHERE AVERAGE TEMPS AND DEW
POINTS WERE IN THE UPPER 70S AND UPPER 60S. EXPERIMENTAL HRRR
SUGGESTS A FEW STORMS WILL FIRE THIS AFTERNOON FROM SOUTHEAST SOUTH
DAKOTA INTO EASTERN NEBRASKA ON WESTERN SIDE OF INSTABILITY
GRADIENT...AND ALREADY ARE SEEING THE START OF THAT CONVECTION IN
SOUTH DAKOTA AND NEAR THE OMAHA METRO. THESE STORM SHOULD CONTINUE
TO MOVE OFF TO THE NORTHEAST RATHER QUICKLY...AND COULD SEE A
WIND/HAIL EVENT BEFORE EXITING OUR CWA LATE THIS AFTERNOON.
ATTENTION THEN TURNS TO POTENTIALLY MORE WIDESPREAD SEVERE IGNITING
WELL TO OUR SOUTHWEST IN THE HIGHS PLAINS FROM WESTERN NEBRASKA INTO
THE TEXAS PANHANDLE. HI-RES MODELS ALL HAVE SOME VARIATION IN THIS
CONVECTION...AND SPREAD IT INTO SOUTHEAST NEBRASKA LATER THIS
EVENING. WHAT KIND OF ATMOSPHERE WILL BE AVAILABLE FOR THOSE STORMS
IS STILL IN QUESTION...MAINLY DUE TO ON-GOING STORMS IN CENTRAL
KANSAS INTO NORTH CENTRAL OKLAHOMA. THE MOST LIKELY SCENARIO BASED
ON LATEST HRRR AND RAP IS SOME OF THE KANSAS CONVECTION WILL TRACK
NORTHEAST INTO EASTERN NEBRASKA LATE THIS AFTERNOON THEN EXIT TO THE
EAST THIS EVENING. GIVEN CURRENT INSTABILITY AND SHEAR...ROTATING
STORMS ARE LIKELY WITH AT LEAST SOME HAIL THREAT AND MOST NOTABLY
WIND. TORNADOES ARE STILL A THREAT AS WELL IF FORECAST STORM-
RELATIVE 0-1KM HELICITY NEAR 150 M2/S2 IS REALIZED. MODELS DEPICT
THIS AREA OF CONVECTION WILL BOW OUT ACROSS WESTERN IOWA BEFORE
EXITING TO OUR EAST.
THEN SECONDARY SURGE OF STORMS IS SLATED TO RACE NORTHEAST FROM
OKLAHOMA PANHANDLE AND ENTER SOUTHEAST NEBRASKA AT MID TO LATE
EVENING. SOME RECOVERY IN AIRMASS IS LIKELY AFTER EARLIER STORMS. AN
INCREASE IN LOW LEVEL JET TO NEAR 50KT IS LIKELY AS INCREASINGLY
DIFFLUENT MID LEVEL FLOW OVERSPREADS THE PLAINS. SO LATER-EVENING
STORMS WILL STILL HAVE VIGOROUS WIND FIELDS TO PLAY WITH...
SUPPORTING AT LEAST SOME TORNADO AND WIND THREAT PAST DARK. TREND IN
HOURLY UPDATES OF HRRR FORECASTS HAS BEEN FOR NORTHERNMOST SEVERE
STORMS TO ONLY GRAZE FAR SOUTHEAST NEBRASKA IN THE 03Z TO 06Z
TIMEFRAME. SO WILL KEEP A CLOSE EYE ON IF THIS TREND CONTINUES.
WHILE SECOND LINE OF STORMS MOVES EAST OF OUR CWA AFTER
MIDNIGHT...MORE SHOWERS/STORMS ARE FORECAST TO DEVELOP IN WESTERN
NEBRASKA AND TRACK INTO NORTHEAST NEBRASKA OVERNIGHT AS UPPER LOW
MOVES INTO THE NORTHERN PLAINS. A WAVE ROTATING AROUND THIS FEATURE
WILL LIKELY IGNITE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS MUCH
OF SUNDAY IN SOUTH DAKOTA AND NORTHERN NEBRASKA. GFS SUGGESTS UP TO
1000 J/KG OF SURFACE-BASED CAPE WILL BE AVAILABLE FOR THIS ACTIVITY
INTO THE AFTERNOON.
AFTER WAVE PASSES SUNDAY AFTERNOON...STRONG COLD ADVECTION WILL
OVERSPREAD OUR AREA...DROPPING 850 TEMPERATURES TO BELOW 0C ON
MONDAY IN OUR NORTH. COULD SEE A PASSING SHOWER ALONG THIS COLD PUSH
SUNDAY NIGHT...BUT THE MAIN WEATHER STORY WILL BE COOLER AND DRIER
AIR BEING PUSHED INTO THE REGION ON BRISK NORTHWEST WINDS MONDAY.
HIGHS IN THE LOWER 60S SHOULD BE ALL WE CAN MUSTER THEN. THE COOL
WEATHER CONTINUES INTO TUESDAY WHEN SURFACE HIGH PRESSURE SETTLES
INTO THE REGION. COULD SEE SUB-40 LOWS IN MANY AREAS TUESDAY MORNING.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 332 PM CDT SAT MAY 16 2015
MID LEVEL FLOW PATTERN WILL RELOAD AS ANOTHER UPPER LOW SETTLES INTO
THE SOUTHWEST STATES AT MID WEEK ON HEELS OF EXITING NORTHERN PLAINS
LOW. THIS WILL BRING GENERALLY SOUTHWEST FLOW OVER THE MIDDLE OF THE
COUNTRY...WITH A POTENT WAVE EJECTING INTO THE PLAINS ON WEDNESDAY.
THAT WAVE WILL BRING OUR NEXT CHANCE FOR SHOWERS AND THUNDERSTORMS
BEGINNING TUESDAY NIGHT BEFORE EXITING WEDNESDAY NIGHT. MOISTURE
RETURN LOOKS MINIMAL...SO SEVERE STORMS APPEAR UNLIKELY DESPITE THE
CALENDAR SAYING WE ARE IN MID TO LATE MAY.
SOME WEAK RIDGING BEHIND EXITING WAVE SUGGESTS RAIN CHANCES WILL BE
AT A MINIMUM TO END THE WEEK...BUT SOUTHWESTERN TROUGH AXIS BEGINS
LIFTING TOWARD THE PLAINS BY SATURDAY. WILL BRING STORM CHANCES BACK
INTO THE FORECAST THEN...BUT DETAILS WILL HAVE TO BE WORKED OUT WITH
TIME ON DEGREE OF POTENTIAL SEVERE RISK.
&&
.AVIATION...(18Z TAFS FOR KOFK...KLNK AND KOMA.)
ISSUED AT 1230 PM CDT SAT MAY 16 2015
ALL THREE TAF SITES WERE VFR AS OF 17Z. A BAND OF SHOWERS AND
THUNDERSTORMS IS STILL EXPECTED TO DEVELOP ACROSS KANSAS AND MOVE
ACROSS ALL THREE TAF SITES THIS EVENING AND OVERNIGHT. ISOLATED
TSRA COULD DEVELOP ABOUT ANYTIME AROUND 21Z BUT EXPECTING THE
BETTER CHANCE OF ORGANIZED STORMS TO OCCUR AFTER 00Z. THIS IS
COVERED WITH TEMPO GROUPS IN ALL TAFS AND WILL LIKELY NEED TO BE
ADJUSTED ONCE ACTIVITY DEVELOPS. THUNDERSTORMS WILL MOVE NORTHEAST
LATE IN THE FORECAST PERIOD AND HAVE TRENDED THEM OUT OF KOMA AND
KLNK AFTER 14Z. DUE TO WRAP AROUND ACTIVITY AROUND DEEP SURFACE
LOW OVER EASTERN SOUTH DAKOTA BY 15Z...WILL KEEP THREAT OF -RA OR
EVEN -TSRA IN THE KOFK VICINITY THROUGH 18Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
SHORT TERM...DERGAN
LONG TERM...DERGAN
AVIATION...MEYER
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
850 PM PDT SUN MAY 17 2015
.SYNOPSIS...PRECIPITATION CHANCES WILL SPREAD FROM WEST TO EAST
ACROSS THE REGION TONIGHT AND MONDAY AS A LOW PRESSURE SYSTEM MOVES
INLAND. THIS SYSTEM WILL THEN MOVE SLOWLY NORTHEAST WITH SHOWERS
LINGERING MAINLY NORTH OF LAS VEGAS TUESDAY INTO TUESDAY NIGHT. YET
ANOTHER STORM WILL IMPACT THE AREA LATER IN THE WEEK. TEMPERATURES
ARE EXPECTED TO REMAIN BELOW NORMAL THROUGH THE WEEK.
&&
.UPDATE...RECENT RADAR RETURNS INDICATED AN AREA OF LIGHT SHOWERS
DEVELOPING OVER DEATH VALLEY NATIONAL PARK ON THE SOUTHEAST
PERIPHERY OF THE CENTRAL CALIFORNIA LOW. THE LATEST HRRR AND 00Z NAM
QPF DEPICTIONS PICKED UP THIS GENERAL TREND AND SPREAD PRECIPITATION
UP THROUGH THE PAHRUMP VALLEY...AMARGOSA VALLEY AND BEATTY BEFORE
06Z. RAINFALL AMOUNTS ARE EXPECTED TO BE QUITE LIGHT GIVEN THE LIGHT
RETURNS AND THE 15-20 MPH NORTHWARD MOVEMENT OF THE SHOWERS. THE
POP/WX/QPF GRIDS WERE ADJUSTED ACCORDINGLY. OTHERWISE...THE FORECAST
IS ON TRACK WITH SHOWERS SLOWLY SPREADING TO THE SOUTHEAST MONDAY
MORNING THROUGH AFTERNOON. &&
.AVIATION...FOR MCCARRAN...SOUTHEAST WINDS GUSTING AROUND 20-25 KTS
ARE EXPECTED TO DECREASE BEFORE 06Z AND BECOME A MORE TYPICAL
SOUTH/SOUTHWEST DRAINAGE WIND AROUND 10 KTS THE REST OF THE NIGHT.
WINDS MAY BECOME LIGHT AND VARIABLE MONDAY MORNING BUT WINDS BY
EARLY AFTERNOON WILL BE SOUTHERLY 10-15 KTS WITH GUSTS POSSIBLY UP
TO 20 KTS. SCT CLOUDS WITH BASES AS LOW AS 10 KFT WILL LINGER
THROUGH TONIGHT AND WILL PROBABLY BECOME BKN MONDAY MORNING AND
COULD LOWER TO 8 KFT AS SHOWERS MOVE ACROSS THE AREA BY LATE MORNING
OR EARLY AFTERNOON. SHOWERS WILL BE POSSIBLE THROUGH MONDAY EVENING
BUT SHOULD END OVERNIGHT.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...SOUTH TO SOUTHEAST WINDS BETWEEN 10-15 KTS WITH GUSTS
20-25 KTS OVER MOST AREAS THROUGH MUCH OF TONIGHT WITH SCATTERED TO
NUMEROUS SHOWERS OVER THE SOUTHERN SIERRA. ISOLATED SHOWERS WILL BE
POSSIBLE ACROSS THE REST OF INYO COUNTY AND OVER ESMERALDA AND
CENTRAL NYE COUNTIES. MAINLY TYPICAL NIGHT TIME DRAINAGE WINDS WILL
DEVELOP LATER TONIGHT. PRECIPITATION CHANCES WILL SPREAD ACROSS THE
REST OF THE AREA MONDAY AS A STORM SYSTEM MOVES THROUGH THE REGION.
SOUTHERLY WINDS WILL INCREASE AGAIN MONDAY TO 10-18 KTS WITH GUSTS
20-30 KTS. CIGS WITH SHOWERS TONIGHT AND MONDAY WILL LOWER TO 5-7
KFT.
&&
.PREV DISCUSSION...
240 PM PDT SUN MAY 17 2015
.SHORT TERM...THROUGH TUESDAY NIGHT.
AN UPPER LOW WAS ALONG THE COAST THIS AFTERNOON WITH WEAK CONVECTION
ACROSS PORTIONS OF THE FORECAST AREA. WEB CAMS AND RADAR SHOWED SOME
SHOWERS OVER THE SIERRA. OTHERWISE THERE IS NO REAL EVIDENCE OF
PRECIPITATION REACHING THE GROUND SO FAR. THE UPPER LOW WILL MOVE
INLAND TONIGHT WITH PRECIPITATION CHANCES INCREASING IN THE SIERRA
WITH AT LEAST A SLIGHT CHANCE ACROSS MUCH OF INYO COUNTY AS WELL AS
ESMERALDA...CENTRAL NYE AND NORTHERN LINCOLN COUNTIES. THE LOW
CENTER WILL MOVE TO ROUGHLY THE NV/CA LINE MONDAY WITH PRECIPITATION
CHANCES SPREADING TO ALL BUT SOUTHERN SAN BERNARDINO COUNTY. THE
BEST CHANCE OF ANY DECENT PRECIPITATION REMAINS OF THE HIGHER
TERRAIN. THE LOW WILL START TO WEAKEN MONDAY NIGHT BUT PRECIPITATION
CHANCES WILL CONTINUE IN MOST AREAS. THE LOW WILL CONTINUE TO WEAKEN
AND MOVE NORTHEAST TUESDAY WITH WITH PRECIPITATION CHANCES LINGERING
NORTH OF LAS VEGAS. WITH THE AREA BETWEEN TWO SYSTEMS TUESDAY NIGHT
WE SHOULD SEE ANY LINGERING PRECIPITATION ENDING BY LATE EVENING.
TEMPERATURES WILL REMAIN BELOW NORMAL ACROSS THE AREA THROUGH
TUESDAY. SNOW LEVELS WITH THIS SYSTEM WILL MAINLY BE ABOVE 8000-8500
FEET. THE HIGHER ELEVATIONS OF THE SIERRA AND THE WHITE
MOUNTAINS AND SPRING MOUNTAINS COULD SEE A FEW INCHES OF SNOW.
.LONG TERM...WEDNESDAY THROUGH SUNDAY NIGHT.
WELL THE VACATION FROM TYPICAL MAY WEATHER CONTINUES INTO THE START
OF THE MEMORIAL DAY WEEKEND. YET ANOTHER COLD MID/UPPER LOW AWAITS
TO MOVE ON IN FOR WEDNESDAY AS IT APPROACHES THE CENTRAL COAST OF
CALIFORNIA. AS THE LOW APPROACHES THE COAST, IT SHOULD SPREAD IN
ENOUGH MID-LEVEL MOISTURE TO SPARK OFF A FEW SHOWERS AND PERHAPS A
THUNDERSTORM OVER THE NORTHWEST CWFA ESPECIALLY THE SOUTHERN SIERRA,
WHITE MOUNTAINS, THE OWENS VALLEY AND ESMERALDA COUNTY IN THE LATE
MORNING AND AFTERNOON. OTHERWISE LOOK FOR A DRY DAY WITH WINDS
PICKING UP IN THE AFTERNOON FROM THE SOUTH TO SOUTHWEST AND GUSTING
TO 20-30 MPH. HIGH TEMPS WILL WARM UP A FEW DEGREES FROM TUESDAY BUT
STILL BE 5-7 DEGREES BELOW NORMAL.
MOST OF WHATEVER CONVECTIVE ACTIVITY WE SEE DURING THE DAY ON
WEDNESDAY SHOULD DIE OFF WITH THE LOSS OF HEATING DURING THE EARLY
EVENING. THE CENTER OF THE LOW ITSELF IS EXPECTED TO PASS NEAR POINT
CONCEPTION ON THURSDAY AFTERNOON AND HEAD TOWARD THE COAST OF SOCAL
BY THURSDAY NIGHT. ONCE AGAIN IT APPEARS WE COULD MAINLY SEE
DIURNALLY DRIVEN AFTERNOON AND EVENING SHOWERS AND PERHAPS A FEW
THUNDERSTORMS ACROSS THE NORTHERN HALF OF THE AREA. HOWEVER, SOME
SHOWERS COULD STICK AROUND INTO THURSDAY NIGHT AS THE LOW CENTER
GETS CLOSER. SNOW LEVELS SHOULD DROP TO 8500 FEET THEN SO THE
HIGHEST ELEVATIONS MAY SEE A FEW INCHES OF SNOW IF ANY HEAVIER OR
STEADIER SHOWERS PASS OVER THEM. THE LOW CENTER IS EXPECTED TO PASS
ACROSS SOCAL ON FRIDAY DURING THE MORNING THEN LIFT NORTHEAST INTO
MOHAVE COUNTY BY THE AFTERNOON. AT THIS TIME, THE OPERATIONAL MODELS
KEEP THE BULK OF THE MOISTURE NORTH OF WHERE THE CENTER OF THE LOW
TRACKS AND MOST OF THE QPF THEY DEVELOP. THUS WE HAVE CONTINUED TO
KEEP THE GREATEST SHOWER CHANCES NORTH OF I-40 AND OVER THE HIGHER
ELEVATIONS. HIGH TEMPS ON THURSDAY AND FRIDAY SHOULD BE ABOUT 8-12
DEGREES BELOW NORMAL. EVEN WHERE WE STAY DRY THERE LOOKS TO BE A
DECENT CIRRUS SHIELD PASSING OVER THE AREA ON THURSDAY AS THE JET
STREAM PASSES BY JUST TO OUR SOUTH AND ENOUGH MID-LEVEL MOISTURE ON
FRIDAY TO GENERATE PLENTY OF CUMULUS. THUS THE CLOUDS AND COOLER AIR
ALOFT COURTESY OF THE LOW CENTER WILL AID GREATLY IN HOLDING DOWN
TEMPS.
MOST SHOWER ACTIVITY SHOULD END BY FRIDAY NIGHT AS THE LOW CENTER
PULLS EAST, HOWEVER, AS THE FLOW ALOFT TURNS NORTHWEST ADDITIONAL
ENERGY DROPPING SOUTH MAY TRIGGER A FEW SHOWERS OVER THE SOUTHERN
GREAT BASIN ON SATURDAY AND TO A LESSER EXTENT ON SUNDAY. ELSEWHERE,
IT SHOULD REMAIN DRY. DESPITE THE FLOW ALOFT TURNING NORTH, TEMPS
WILL START TO WARM IN RESPONSE TO RISING HEIGHTS AND MAY GET BACK
CLOSER TO NORMAL VALUES FOR HIGHS BY NEXT SUNDAY. ENJOY THE SAVINGS
ON YOUR ELECTRIC BILL WHILE THE AIR CONDITIONERS AND FANS GET A
BREAK. && &&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
UPDATE...ADAIR
SHORT TERM/AVIATION...HARRISON
LONG TERM...STACHELSKI
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
325 PM MDT SAT MAY 16 2015
.SYNOPSIS...
PRECIPITATION AND WINDS OVERALL SHOULD DECREASE TONIGHT...WITH QUIET
AND WARMER WEATHER SUNDAY. ANOTHER FRONT AND STORM SYSTEM WILL
COLLIDE BY MONDAY NIGHT AND TUESDAY...WITH ANOTHER WET AND COOLER
PERIOD...ESPECIALLY FOR LOCALES EXTENDING FROM THE RIO GRANDE VALLEY
EASTWARD ACROSS THE EASTERN PLAINS. DRYING EXPECTED THEREAFTER WITH
SOME WARMING BUT SOME STORMS WILL STILL BE POSSIBLE ACROSS AT LEAST
OVER THE FAR EASTERN PLAINS AND NORTHERN MOUNTAINS THE END OF NEXT
WEEK.
&&
.DISCUSSION...
PRECIPITATION AND WINDS OVERALL SHOULD DECREASE OVERNIGHT...BUT WITH
SOME POSSIBLE EXCEPTIONS. WIND ADVY SPOTTY AT BEST THIS AFTERNOON
AND STRONGEST GUSTS APPEAR TO HAVE BEEN CONVECTION
RELATED...HOWEVER...H7 WINDS INCREASE OVERNIGHT OVER PARTS OF THE
NORTHEAST AS THE UPPER LOW/TROF SWINGS OUT INTO THE PLAINS
STATES...SO WILL KEEP THE NPW GOING. WILL ALSO KEEP THE CURRENT WSW
AS IS...WITH GFS/NAM NOT INDICATING MUCH SNOW AFTER 00Z. THE HRRR ON
THE OTHER HAND...KEEPS SOME SNOW GOING OVER THE NRN SANGRE DE CRISTO
MTS...AND THE FORECAST MOIST W-NWLY BOUNDARY LAYER WINDS INTO THE
SANGRES COULD CONTINUE TO ACCUMULATE SOME SNOW INTO THE LATE
EVENING. ARRGH...WILL HAVE TO CONTINUE TO MONITOR...BUT GRIDS HAVE
ANOTHER 1 TO 3 INCHES IN THIS AREA TONIGHT...ALTHOUGH THAT WOULD BE
UNDERDONE IF HRRR IS RIGHT. BUT NO MODEL SEEMS TO BE DOING THAT WELL
TODAY.
DRIER AND WARMER SUNDAY INTO MONDAY. THEN ANOTHER WETTER AND COOLER
PERIOD MONDAY NIGHT THROUGH TUESDAY AS ANOTHER SYSTEM COMING FROM
THE WEST AND A FRONT FROM THE EAST COLLIDE TO PRODUCE WIDESPREAD
PRECIPITATION. TRIMMED DOWN POPULATED QPF WHICH TOTALED A LARGE
SWATH OF A COUPLE OF INCHES JUST MONDAY NIGHT ALONG THE CENTRAL MT
CHAIN TO THE PECOS VALLEY. BUT SOME GENEROUS AMOUNTS POSSIBLE
TUESDAY AS WELL AS THE UPPER SYSTEM SWINGS OVER NE NM. H7 TEMPS NOT
AS COLD AS WITH PRESENT SYSTEM SO NOT ANTICIPATING THE LOWER SNOW
LEVELS THAT HAVE BEEN OBSERVED TODAY.
LOTS OF VARIATION MID TO LATE NEXT WEEK...THE GFS IS DRIER AND WINDY
WHILE THE ECMWF IS WETTER THANKS TO A FRONT ON FRIDAY...SURPRISE. IN
ANY EVENT...THE UNSETTLED WEATHER PATTERN APPEARS TO CONTINUE INTO
THE MEMORIAL DAY WEEKEND.
&&
.FIRE WEATHER...
NO WIDESPREAD FIRE WEATHER CONCERNS THROUGH THE FORECAST PERIOD AS
THE WEATHER PATTERN CONTINUES TO FAVOR UNSETTLED...ACTIVE WEATHER
AND SEASONABLY COOLER THAN NORMAL TEMPERATURES.
CURRENT UPPER LEVEL TROUGH IS CROSSING NM THIS PM AND WILL SHIFT TO
THE EAST TONIGHT. SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH
THE EVENING HOURS...MAINLY NORTH OF I 40. SHOWERS MAY LINGER OVER
THE NORTH LATE TONIGHT. RH RECOVERIES WILL BE GOOD TO EXCELLENT.
A MAINLY DRY DAY IS IN STORE SUNDAY AS A WEAK UPPER LEVEL RIDGE
MOVES OVER. DESPITE THE RIDGE...HIGH TEMPERATURES REMAIN BELOW
AVERAGE FOR MID MAY. MODELS INDICATING RESIDUAL MOISTURE WILL
COMBINE WITH DAYTIME HEATING TO PRODUCE A FEW SHOWERS AND MAYBE
THUNDERSTORMS OVER THE NORTHERN MOUNTAINS.
A BACK DOOR COLD FRONT WILL DROP SOUTH INTO THE NORTHEAST EAST
SUNDAY NIGHT. IT WILL STALL MONDAY BEFORE RACING SOUTH AND WEST
MONDAY NIGHT. STRONG EAST WINDS INTO THE RIO GRANDE VALLEY ARE
POSSIBLE. MEANWHILE THE NEXT UPPER LEVEL TROUGH WILL BE APPROACHING
MONDAY THEN SWEEP ACROSS THE STATE MONDAY NIGHT INTO TUESDAY. THE
COMBINATION OF LOW LEVEL MOISTURE BEHIND THE FRONT...INSTABILITY
FROM THE UPPER TROUGH...AND DEEP MOISTURE GETTING DRAWN NORTHWEST
INTO NM FROM TX WILL RESULT IN A SIGNIFICANT RAIN EVENT FOR MUCH OF
THE FORECAST AREA...WITH THE LEAST FAVORED AREA THE SOUTHWEST AND
THE MOST FAVORED AREA ALL OF THE EAST. ALL THE MODELS HAVE A FAIRLY
WIDESPREAD...SOAKING RAIN EVENT WITH ONE TO TWO INCH RAIN AMOUNTS
FOR THE EASTERN PLAINS AND LOCALLY UP TO THREE INCHES IN THE MONDAY
NIGHT THROUGH TUESDAY TIME PERIODS.
YET ANOTHER STORM WILL BE ORGANIZING OFF THE CA COAST LATER NEXT
WEEK. THE FAR EASTERN PLAINS WILL BE UNDER THE GUN FOR SHOWERS AND
STORMS WEDNESDAY INTO FRIDAY. A DRY LINE WILL WOBBLE BACK WEST AT
NIGHT AND TO THE EAST DURING THE DAY. ELSEWHERE SHOULD BE MOSTLY
DRY. ALL AREAS WILL REMAIN BELOW NORMAL. WINDS WILL BE ON THE
INCREASE NEXT FRIDAY AND SATURDAY. BRIEF CRITICAL FIRE WEATHER
CONDITIONS ARE NOT OUT OF THE QUESTION OVER THE SOUTHERN PORTION
OF THE MIDDLE RIO GRANDE VALLEY FRIDAY AFTERNOON.
A PORTION OF THE ABOVE MENTIONED STORM WILL CROSS NM SATURDAY WHILE
ANOTHER PORTION HANGS BACK OVER UT AND AZ. THIS LAZY TROUGH WILL
INCH ITS WAY EAST WHILE KEEPING SHOWERS AND STORMS IN THE FORECAST
FOR THE NORTH AND EAST LATE NEXT WEEKEND INTO EARLY THE FOLLOWING
WEEK. 40
&&
.AVIATION...
18Z TAF CYCLE
AN UPPER LEVEL TROUGH WILL SWING ACROSS NM THIS AFTERNOON. A
SURFACE COLD FRONT WILL ACCOMPANY THE TROUGH. PLENTY OF LOW LEVEL
MOISTURE AND AN UNSTABLE ATMOSPHERE WILL PRODUCE SHOWERS AND
THUNDERSTORMS THROUGH AT LEAST 03Z. A FEW STORMS OVER THE NE
COULD BE STRONG TO SEVERE THIS PM. BRIEF MVFR TO IFR CONDITIONS
LIKELY WITH ANY STORM. WET SNOW WILL FALL IN THE MTS WITH
OBSCURATIONS. WIND GUSTS APPROACHING 50 KT WITH THE STRONGEST
STORMS. OTHERWISE...MOSTLY VFR CONDITIONS. AREAS OF FOG WILL
DEVELOP LATE TONIGHT...ESPECIALLY OVER WRN AND CENTRAL NM WHERE
WINDS WILL BE LOWEST. FOR NOW HAVE VCFG IN MANY OF THE TAF SITES.
40
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 37 68 42 77 / 20 0 0 10
DULCE........................... 30 64 35 69 / 40 5 5 20
CUBA............................ 32 64 38 69 / 30 5 5 10
GALLUP.......................... 29 66 35 76 / 20 0 0 10
EL MORRO........................ 28 63 33 69 / 20 0 0 10
GRANTS.......................... 30 67 32 74 / 20 0 0 10
QUEMADO......................... 32 64 34 71 / 10 0 0 5
GLENWOOD........................ 37 72 43 80 / 5 0 0 5
CHAMA........................... 27 59 30 63 / 60 10 10 20
LOS ALAMOS...................... 37 61 44 66 / 30 5 5 10
PECOS........................... 35 62 39 64 / 20 5 5 10
CERRO/QUESTA.................... 29 63 33 64 / 50 10 10 20
RED RIVER....................... 27 53 32 56 / 60 10 10 40
ANGEL FIRE...................... 26 58 30 59 / 50 10 5 30
TAOS............................ 27 64 35 67 / 30 5 5 20
MORA............................ 34 62 38 61 / 30 0 5 20
ESPANOLA........................ 38 68 42 71 / 20 5 5 10
SANTA FE........................ 38 62 44 66 / 20 5 5 10
SANTA FE AIRPORT................ 36 67 40 71 / 20 5 5 10
ALBUQUERQUE FOOTHILLS........... 39 68 43 73 / 20 0 0 10
ALBUQUERQUE HEIGHTS............. 44 70 49 76 / 10 0 0 5
ALBUQUERQUE VALLEY.............. 39 72 46 80 / 10 0 0 5
ALBUQUERQUE WEST MESA........... 43 71 48 77 / 20 0 0 5
LOS LUNAS....................... 39 71 44 78 / 10 0 0 5
RIO RANCHO...................... 42 70 48 76 / 20 0 0 5
SOCORRO......................... 43 74 47 81 / 10 0 0 5
SANDIA PARK/CEDAR CREST......... 38 64 44 70 / 20 0 0 10
TIJERAS......................... 37 68 40 73 / 20 0 0 10
MORIARTY/ESTANCIA............... 32 66 32 70 / 10 0 0 10
CLINES CORNERS.................. 34 65 39 67 / 10 0 0 10
GRAN QUIVIRA.................... 36 66 38 71 / 10 0 0 10
CARRIZOZO....................... 41 69 44 76 / 5 0 0 10
RUIDOSO......................... 40 65 46 72 / 5 0 0 10
CAPULIN......................... 35 67 40 63 / 30 0 10 20
RATON........................... 36 72 41 68 / 30 0 10 30
SPRINGER........................ 38 72 42 68 / 30 0 5 20
LAS VEGAS....................... 36 66 37 65 / 20 0 0 20
CLAYTON......................... 45 76 47 70 / 30 0 5 20
ROY............................. 42 71 45 67 / 20 0 5 20
CONCHAS......................... 47 77 49 75 / 10 0 5 10
SANTA ROSA...................... 45 75 47 76 / 5 0 0 10
TUCUMCARI....................... 48 80 49 78 / 5 0 5 10
CLOVIS.......................... 46 77 48 78 / 5 0 10 10
PORTALES........................ 47 77 49 79 / 5 0 10 10
FORT SUMNER..................... 46 77 48 79 / 5 0 5 10
ROSWELL......................... 48 80 50 84 / 5 0 5 10
PICACHO......................... 44 74 47 76 / 5 0 0 10
ELK............................. 41 69 46 72 / 5 0 5 10
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR THE FOLLOWING ZONES...
NMZ523-526-529>540.
WINTER WEATHER ADVISORY UNTIL 6 PM MDT THIS EVENING FOR THE
FOLLOWING ZONES...NMZ510-511-513-514.
&&
$$
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1042 PM CDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 1042 PM CDT SUN MAY 17 2015
ROLLA STILL SUSTAINED AT OVER 40KTS WITH TURTLE MOUNTAIN RAWS
STILL GUSTING TO 61 MPH. WILL EXTEND THE HIGH WIND WARNING A
COUPLE OF HOURS...TILL 1AM CDT. RAP PRESSURE RISES ON THE DECREASE
SO A 1AM EXPIRATION SHOULD BE GOOD.
UPDATE
ISSUED AT 1004 PM CDT SUN MAY 17 2015
HEADLINES WILL REMAIN AS IS. AN ARGUMENT CAN BE MADE FOR A SMALL
AREA FOR BLIZZARD HEADLINES WITH BOTH ROLLA AND HARVEY REPORTING
STRONG WINDS GUSTING 35-45KTS AND 1/4 MILE VIS IN HEAVY SNOW.
HOWEVER...VIS HAVE BEEN JUMPING FROM 1/4 TO 3/4 AND DO NOT FEEL
THE SMALL AREA AND TIME DURATION JUSTIFIES AN UPGRADE. THUS WILL
MAINTAIN THE WINTER WEATHER ADVISORY AS IS WITH NEAR BLIZZARD
WORDING AND OTHER DIRE TERMINOLOGY IN THE OVERVIEW AND SEGMENT.
HIGH WIND WARNING OVER MY FAR NORTHEAST EXPIRES AT 11PM. WILL
REVISIT IN 30-45 MIN FOR A POSSIBLE EXTENSION.
UPDATE
ISSUED AT 710 PM CDT SUN MAY 17 2015
RAIN CHANGING OVER TO SNOW AS TEMPERATURES AT THE SURFACE AND
ALOFT COOL. HAVE HAD A MIX OF SLEET SOUTH CENTRAL WHERE SOUNDINGS
INDICATE A WARM LAYER ALOFT...COLD LAYER AROUND 850MB...AND
SURFACE TEMPERATURES IN THE MIDDLE 30S. THE WARM LAYER WILL COOL
WITH ALL SNOW BY 01-02Z.
HEADLINES ALL STILL VALID...AND WILL STAY THE COURSE WITH THIS
UPDATE.
UPDATE ISSUED AT 608 PM CDT SUN MAY 17 2015
OPTED TO ISSUE A HIGH WIND WARNING OVER ROLETTE AND PIERCE
COUNTIES. WINDS CONTINUE TO GUST OVER 60 MPH AT OBSERVING SITES
ACROSS MY FAR NORTHEAST. CANNOT IGNORE THIS SO WENT WITH A
WARNING. OTHER EDITS MINOR FOR NOW...ANOTHER UPDATE OUT BY 0030Z.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 330 PM CDT SUN MAY 17 2015
SIGNIFICANT STORM IMPACTING NORTH DAKOTA WILL BEGIN TO WANE
TONIGHT AND EXIT THE REGION ON MONDAY. AS COLDER AIR WRAPS UP
INTO THE SYSTEM SNOW WILL START TO ACCUMULATE ACROSS THE NORTH
CENTRAL...WITH 2 TO NEAR 6 INCHES EXPECTED. STRONG WINDS WILL
CONTINUE THROUGH THE NIGHT. WILL KEEP WIND ADVISORY THROUGH 7 PM
NORTH CENTRAL THEN TRANSITION TO A WINTER WEATHER ADVISORY FOR
THE SNOW AND MENTION THE STRONG WINDS IN THE WINTER WEATHER
ADVISORY. WILL MAINTAIN WIND ADVISORY THROUGH THE NIGHT SOUTH
CENTRAL.
THE RAIN WILL SIGNIFICANTLY DECREASE AFTER MIDNIGHT. UNTIL THEN
THERE IS A FLOOD ADVISORY FOR EAST CENTRAL NORTH DAKOTA WHERE
WIDESPREAD WARM CONVEYER BELT PRECIP HAS BEEN QUASI STATIONARY
TODAY.
FINALLY...WIDESPREAD FREEZING TEMPERATURES ARE EXPECTED ACROSS WEST
AND CENTRAL NORTH DAKOTA TONIGHT. WILL LET THE WINTER WEATHER
ADVISORY AND ITS SNOW AMOUNTS STAND IN FOR THE FREEZE WARNING
NORTH CENTRAL. ACROSS THE WEST AND SOUTH WILL ISSUE A FREEZE
WARNING TONIGHT AND EARLY MONDAY.
MONDAY WILL BECOME SUNNY WITH DIMINISHING WINDS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 PM CDT SUN MAY 17 2015
COOL AND DRY WILL CHARACTERIZE THE LONG TERM.
HIGH PRESSURE WILL BUILD IN BEHIND THE DEPARTING WEEKEND STORM
MONDAY NIGHT. THIS WILL LEAD TO CLEAR SKIES AND LIGHT WIND.
TEMPERATURES OVERNIGHT WILL LIKELY FALL INTO THE MID 20S FOR MOST
OF NORTH DAKOTA. A FREEZE WARNING WILL BE POSSIBLE WITH WIDESPREAD
FROST.
THE REST OF THE WEEK LOOKS DRY WITH SURFACE HIGH PRESSURE
REMAINING ENTRENCHED OVER NORTH DAKOTA AND UPPER LEVEL RIDING
BUILDING WEST. THIS WILL KEEP MOST OF THE MOISTURE AND STORM
TRACKS THIS WEEK SOUTH OF NORTH DAKOTA.
TEMPERATURES LOOK TO REBOUND INTO THE 60S BY THURSDAY.
THE NEXT CHANCE FOR PRECIPITATION ARRIVES THIS WEEKEND AS THE
RIDGE BREAKS DOWN AND AN UPPER LEVEL LOW MOVES INTO THE PLAINS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 1004 PM CDT SUN MAY 17 2015
WIDESPREAD IFR CONDITIONS IN RAIN AND SNOW WILL CONTINUE THROUGH
TONIGHT. RAIN WILL CONTINUE TO TRANSITION TO ALL SNOW OVERNIGHT.
CONDITIONS WILL IMPROVE NORTHWEST 04-07Z...ELSEWHERE WEST
08-12Z...AND ACROSS CENTRAL NORTH DAKOTA TOMORROW MORNING FROM
WEST TO EAST.
&&
.HYDROLOGY...
ISSUED AT 330 PM CDT SUN MAY 17 2015
HAVE ISSUED AN AREAL FLOOD ADVISORY THROUGH THIS EVENING EAST
CENTRAL. RAINFALL AMOUNTS OF TWO TO 4 INCHES WITH SOME ISOLATED
HIGHER AMOUNTS CAUSING PONDING...AND FLOODED FIELDS. CALLS AND
INQUIRIES SO FAR HAVE REVEALED ROADS TO BE OK WITH SOME MINOR
FLOODING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING UNTIL 10 AM CDT /9 AM MDT/ MONDAY FOR NDZ001-009-
017>020-031>037-040>048-050-051.
WIND ADVISORY UNTIL 7 AM CDT /6 AM MDT/ MONDAY FOR NDZ019-020-
034>037-042-045>048-050-051.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT MONDAY FOR NDZ002>005-
010>013-021>023-025.
HIGH WIND WARNING UNTIL 1 AM CDT MONDAY FOR NDZ005-013.
&&
$$
UPDATE...NH
SHORT TERM...WAA
LONG TERM...AJ
AVIATION...NH
HYDROLOGY...WAA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
955 PM CDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 955 PM CDT SUN MAY 17 2015
RADAR INDICATES WHAT WAS TALKED ABOUT BELOW AND FEEL THE FORECAST
IS WORKING OUT AS EXPECTED. WINDS NEAR THE INTERNATIONAL BORDER BY
ROLLA...CANDO...AND LANGDON STILL NEAR OR INTO WARNING
CRITERIA...BUT THE GENERAL TREND SHOULD BE SLOWLY DIMINISHING.
UPDATE ISSUED AT 700 PM CDT SUN MAY 17 2015
GETTING REPORTS OF SLEET AND SNOW WITHIN THE DEFORMATION ZONE BAND
OF PRECIP ACROSS THE DEVILS LAKE BASIN...AND DID INTRODUCE SLEET
TO THE FORECAST. THIS PRECIP BAND WILL LIKELY START TO SLOWLY
DISSIPATE AS THE MID-LEVEL LOW PROPAGATES INTO NORTHERN MINNESOTA
(AND ANOTHER BAND OF PRECIP DEVELOPS EAST OF THE VALLEY). RAP/HRRR
SUGGESTING THIS BAND OF PRECIP WILL REMAIN RELATIVELY STATIONARY
THROUGH MIDNIGHT WHILE DISSIPATING. NOT SURE HOW MUCH SNOW WILL
ACCUMULATE ON TOP OF THE WARM GROUND...BUT REDUCED VSBY WILL BE AN
ISSUE. NEAR BLIZZARD CONDITIONS ALSO POSSIBLE IF THE P-TYPE CAN
CHANGE TO ALL SNOWFALL (ALTHOUGH THESE CONDITIONS WOULD BE FOR
LESS THAN 3 HOURS...SO A BLIZZARD WARNING IS NOT ANTICIPATED).
WILL NOT MESS WITH POPS AT THIS POINT AS MOST AREAS SHOULD
EXPERIENCE AT LEAST SOME PRECIP OVERNIGHT. HOWEVER...DID ADJUST
QPF TO LOWER WITHIN THE MIDDLE AREA OF THE CURRENT DEF BAND ACROSS
THE DVL BASIN AND WHERE THE NEXT DEF BAND IS EXPECTED TO DEVELOP.
UPDATE ISSUED AT 610 PM CDT SUN MAY 17 2015
WILL NEED TO ISSUE A HIGH WIND WARNING ACROSS THE DEVILS LAKE
BASIN FOR THIS EVENING. OBSERVATIONS OF SUSTAINED 40 MPH...AND
GUSTS TO 60 MPH ARE BECOMING MORE WIDESPREAD. THERE HAS ALSO BEEN
A REPORT OF DOWNED TREES IN BOTTINEAU...AND LARGER TREE BRANCHES
DOWN IN DEVILS LAKE. THE LATEST RAP SUGGESTS THE SFC PRESSURE
GRADIENT WILL SLIGHTLY INCREASE THROUGH 03Z...WITH 925MB AND 850MB
WIND SPEEDS SLIGHTLY INCREASING. THUS...STRONG WINDS WITH THE
POTENTIAL TO CAUSE DAMAGE WILL CONTINUE FOR AT LEAST A FEW MORE
HOURS.
WILL KEEP THE WINTER WX ADVISORY IN EFFECT WITH REPORTS THAT THE
PRECIP IS BEGINNING TO CHANGEOVER TO SLEET/SNOW...AND ANTICIPATE
WINTRY WEATHER THIS EVENING AND OVERNIGHT. OF COURSE...IF THE
PRECIP BECOMES ALL SNOW THEN BLIZZARD CONDITIONS MAY BE
POSSIBLE...BUT LIKELY FOR LESS THAN 3 HOURS. WILL MONITOR THE
SITUATION CLOSELY.
ELSEWHERE...THE THREAT FOR TORNADOES ACROSS NW MN APPEARS TO HAVE
DIMINISHED AS THE WARM SECTOR IS PROPAGATING EASTWARD.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 337 PM CDT SUN MAY 17 2015
FIRST OFF...SFC LOW NEAR SISSETON/WAHPETON AREA AT MID AFTN AND
SFC PRESSURE FALLS ARE NOT CENTERED NEAR FOSSTON MN. SO SFC LOW
WILL TACK NORTHEAST TOWARD THAT AREA THIS EVENING. EAST OF SFC LOW
AREA IN DRY SLOT WHERE HEATING OCCURRED FAVORABLE FOR SOME
THUNDERSTORM TO FORM. FOCUS IS FROM ALEXANDRIA NORTH TO EAST OF
FERGUS FALLS....TO BEMIDJI...PARK RAPIDS AND WADENA. SFC AND UPPER
AIR LOW PLACEMENT FAVORS LOW TOPPED SUPERCELLS WITH POSSIBLE
FUNNEL FORMATION. PER SPC NOT EXPECTING WIDESPREAD STORMS THIS
STRONG....BUT COULD BE THRU 00Z. ANOTHER QUESTION IS NW EDGE OF
DEF ZONE PRECIP. RAIN FALLING PER PUBLIC LANGDON-DEVILS LAKE AREA
STILL. MODELS TAKE DRIER AIR WEST AND WANT TO SHUT OFF DEF ZONE
HEAVY PRECIP THIS EVENING LEAVING LIGHT PRECIP OVERNIGHT INTO
MONDAY MORNING IN THE COLD AIR WHERE IT WILL BE COLD ENOUGH FOR
SNOW. SO JUST HOW MUCH SNOW WILL FALL IS QUESTIONABLE. WILL LEAVE
WSW OUT FOR 1-3 INCHES IN DVL BASIN-LANGDON AREAS OVERNIGHT AS TOO
UNCERTAIN TO TINKER WITH IT.
WINDS WILL BE A BIG FACTOR AND CONTINUE TO GUST IN THE 40-55 MPH
RANGE IN DVL BASIN AND SPREAD INTO THE RRV THIS EVE. STRONG WINDS
OVERNIGHT INTO MONDAY MORNING SO HAVE WIND ADVISORIES OUT.
MOVED PRECIP OUT A BIT FASTER THAN EARLIER FCSTS MONDAY. OTHERWISE
COLD AND WINDY. CLEARING OVERSPREADS AREA MON NIGHT AND LIKELY
FREEZE CONDITIONS IN MANY AREAS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 337 PM CDT SUN MAY 17 2015
WELCOME DRY WEATHER TUESDAY AND WEDNESDAY AS HIGH PRESSURE MOVES
IN AND TEMPS BEGIN TO RECOVER.
FOR WED NIGHT THROUGH SUNDAY...SMALL DISCUSSION TODAY DUE TO SEVERE
WEATHER POTENTIAL. BASICALLY KEPT THE THU/FRI PERIOD DRY AND LEFT
PCPN CHANCES AS THEY WERE FOR SAT/SUN. TEMPS LOOK TO RETURN TO NEAR
NORMAL VALUES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 700 PM CDT SUN MAY 17 2015
IFR/LIFR CONDITIONS EXPECTED INTO MONDAY...WITH GRADUALLY
IMPROVING CONDITIONS ON MONDAY. STRONG NORTH WINDS ALONG AND WEST
OF THE VALLEY OVERNIGHT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR NDZ008-016-026>030-038-
039-049-052>054.
HIGH WIND WARNING UNTIL 11 PM CDT THIS EVENING FOR NDZ006-007-
014-015.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT MONDAY FOR NDZ006-007-014-
015-024.
MN...WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR MNZ001>004-007-029.
&&
$$
UPDATE...TG
SHORT TERM...RIDDLE
LONG TERM...GODON/RIDDLE
AVIATION...TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
610 PM CDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 610 PM CDT SUN MAY 17 2015
WILL NEED TO ISSUE A HIGH WIND WARNING ACROSS THE DEVILS LAKE
BASIN FOR THIS EVENING. OBSERVATIONS OF SUSTAINED 40 MPH...AND
GUSTS TO 60 MPH ARE BECOMING MORE WIDESPREAD. THERE HAS ALSO BEEN
A REPORT OF DOWNED TREES IN BOTTINEAU...AND LARGER TREE BRANCHES
DOWN IN DEVILS LAKE. THE LATEST RAP SUGGESTS THE SFC PRESSURE
GRADIENT WILL SLIGHTLY INCREASE THROUGH 03Z...WITH 925MB AND 850MB
WIND SPEEDS SLIGHTLY INCREASING. THUS...STRONG WINDS WITH THE
POTENTIAL TO CAUSE DAMAGE WILL CONTINUE FOR AT LEAST A FEW MORE
HOURS.
WILL KEEP THE WINTER WX ADVISORY IN EFFECT WITH REPORTS THAT THE
PRECIP IS BEGINNING TO CHANGEOVER TO SLEET/SNOW...AND ANTICIPATE
WINTRY WEATHER THIS EVENING AND OVERNIGHT. OF COURSE...IF THE
PRECIP BECOMES ALL SNOW THEN BLIZZARD CONDITIONS MAY BE
POSSIBLE...BUT LIKELY FOR LESS THAN 3 HOURS. WILL MONITOR THE
SITUATION CLOSELY.
ELSEWHERE...THE THREAT FOR TORNADOES ACROSS NW MN APPEARS TO HAVE
DIMINISHED AS THE WARM SECTOR IS PROPAGATING EASTWARD.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 337 PM CDT SUN MAY 17 2015
FIRST OFF...SFC LOW NEAR SISSETON/WAHPETON AREA AT MID AFTN AND
SFC PRESSURE FALLS ARE NOT CENTERED NEAR FOSSTON MN. SO SFC LOW
WILL TACK NORTHEAST TOWARD THAT AREA THIS EVENING. EAST OF SFC LOW
AREA IN DRY SLOT WHERE HEATING OCCURRED FAVORABLE FOR SOME
THUNDERSTORM TO FORM. FOCUS IS FROM ALEXANDRIA NORTH TO EAST OF
FERGUS FALLS....TO BEMIDJI...PARK RAPIDS AND WADENA. SFC AND UPPER
AIR LOW PLACEMENT FAVORS LOW TOPPED SUPERCELLS WITH POSSIBLE
FUNNEL FORMATION. PER SPC NOT EXPECTING WIDESPREAD STORMS THIS
STRONG....BUT COULD BE THRU 00Z. ANOTHER QUESTION IS NW EDGE OF
DEF ZONE PRECIP. RAIN FALLING PER PUBLIC LANGDON-DEVILS LAKE AREA
STILL. MODELS TAKE DRIER AIR WEST AND WANT TO SHUT OFF DEF ZONE
HEAVY PRECIP THIS EVENIGN LEAVING LIGHT PRECIP OVERNIGHT INTO
MONDAY MORNING IN THE COLD AIR WHERE IT WILL BE COLD ENOUGH FOR
SNOW. SO JUST HOW MUCH SNOW WILL FALL IS QUESTIONABLE. WILL LEAVE
WSW OUT FOR 1-3 INCHES IN DVL BASIN-LANGDON AREAS OVERNIGHT AS TOO
UNCERTAIN TO TINKER WITH IT.
WINDS WILL BE A BIG FACTOR AND CONTINUE TO GUST IN THE 40-55 MPH
RANGE IN DVL BASIN AND SPREAD INTO THE RRV THIS EVE. STRONG WINDS
OVERNIGHT INTO MONDAY MORNING SO HAVE WIND ADVISORIES OUT.
MOVED PRECIP OUT A BIT FASTER THAN EARLIER FCSTS MONDAY. OTHERWISE
COLD AND WINDY. CLEARING OVERSPREADS AREA MON NIGHT AND LIKELY
FREEZE CONDITIONS IN MANY AREAS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 337 PM CDT SUN MAY 17 2015
WELCOME DRY WEATHER TUESDAY AND WEDNESDAY AS HIGH PRESSURE MOVES
IN AND TEMPS BEGIN TO RECOVER.
FOR WED NIGHT THROUGH SUNDAY...SMALL DISCUSSION TODAY DUE TO SEVERE
WEATHER POTENTIAL. BASICALLY KEPT THE THU/FRI PERIOD DRY AND LEFT
PCPN CHANCES AS THEY WERE FOR SAT/SUN. TEMPS LOOK TO RETURN TO NEAR
NORMAL VALUES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 107 PM CDT SUN MAY 17 2015
LOT OF ELEMENTS TO COVER IN THE TAFS FOR THE NEXT 24 HOURS. FIRST OF
ALL TSTM CHANCES. HAVE SOME THINNING OF THE CLOUDS ACROSS WEST
CENTRAL MN WHICH COULD POSSIBLY LEAD TO SOME THUNDER YET AT KBJI.
OTHERWISE OTHER TAF LOCATIONS LOOK TO BE TOO FAR WEST. MAIN AREA OF
PCPN APPEARS TO BE PINWHEELING BACK TO THE NW AND MAY GIVE ALL TAF
SITES BUT KDVL A LITTLE BREAK FROM THE STEADY PCPN. EVEN IF IT DOES
GIVE A BREAK IT SHOULD SLIDE BACK TO THE EAST LATER...BUT MAYBE WITH
NOT QUITE SO HEAVY OF PCPN. WINDS WILL REALLY HOWL AT KDVL/KGFK FOR
THE NEXT 24 HOURS AND WILL EVENTUALLY SPREAD TO KFAR/KTVF AND
FINALLY KBJI LATER. TEMPS PLUNGE BEHIND THE SYSTEM SO THERE WILL BE
A SWITCH TO RAIN/SNOW THEN ALL SNOW TONIGHT. QUESTION IS STILL HOW
MUCH THE VSBY WILL BE RESTRICTED BY ANY SNOW...AND DO NOT HAVE A
GOOD IDEA AT THE MOMENT. TAFS WILL HAVE TO BE UPDATED FREQUENTLY I
AM SURE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR NDZ008-016-026>030-038-
049-052-054.
WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR NDZ039-053.
HIGH WIND WARNING UNTIL 11 PM CDT THIS EVENING FOR NDZ006-007-
014-015.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT MONDAY FOR NDZ006-007-014-
015-024.
WIND ADVISORY UNTIL 7 PM CDT THIS EVENING FOR NDZ024.
MN...WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR MNZ001-004-007.
WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR MNZ002-003-029.
&&
$$
UPDATE...TG
SHORT TERM...RIDDLE
LONG TERM...GODON/RIDDLE
AVIATION...GODON
AREA FORECAST DISCUSSION
NWS BISMARCK ND
339 PM CDT SAT MAY 16 2015
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 340 PM CDT SAT MAY 16 2015
CONCERNS THIS FORECAST PERIOD INCLUDE SEVERE WEATHER POSSIBILITY
AND HEAVY RAIN. BY THE END OF THE SHORT TERM THE TRANSITION TO
MUCH COOLER WEATHER WITH SOME SNOW BEGINS TO BE SEEN.
AT 230 PM CDT...SURFACE LOW PRESSURE WAS CENTERED NEAR NORTHWEST
SOUTH DAKOTA WITH AN EAST WEST WARM FRONTAL BOUNDARY EXTENDED
ACROSS NORTH CENTRAL SOUTH DAKOTA. FLOW OVER THE WARM FRONT WAS
GENERATING SHOWERS AND SCATTERED THUNDERSTORMS FROM MOBRIDGE NORTH
TO NEAR MINOT AND NORTH TO THE CANADIAN BORDER.
CONCERNING SEVERE WEATHER POTENTIAL...AN 18Z KBIS SOUNDINGS WAS
CONDUCTED. HRRR FORECAST CAPE VALUES IN THE NEIGHBORHOOD OF 2000
ARE FORECAST TO POOL ACROSS SOUTH CENTRAL INTO SOUTHEAST NORTH
DAKOTA LATE THIS AFTERNOON AND EVENING. EXPECT THE SEVERE WEATHER
POTENTIAL TO EXTEND FROM BISMARCK EAST. TO THE WEST EXPECT MORE
ELEVATED THUNDERSTORMS.
LATE TONIGHT AND SUNDAY...AN UPPER LEVEL LOW SWINGS INTO EASTERN
SOUTH DAKOTA THEN TRACKS NORTHEAST AND SPREADS A LARGE AREA OF THE
RAINSHOWERS ACROSS THE EAST HALF OF THE STATE AND ESPECIALLY THE
JAMES RIVER VALLEY. ACROSS THE NORTH CENTRAL...COOLER AIR WILL
BEGIN A RAIN/SNOW CHANGE OVER. AS THE SURFACE LOW WRAPS UP NORTH
WINDS OF 25 TO 35 MPH WILL BE COMMON ACROSS CENTRAL NORTH DAKOTA
ON SUNDAY.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 340 PM CDT SAT MAY 16 2015
RAIN...SNOW AND COLD TEMPERATURES WILL HIGHLIGHT THE LONG TERM.
THE STORM IMPACTING NORTH DAKOTA SATURDAY AND SUNDAY WILL CONTINUE
TO INFLUENCE THE REGION THROUGH MONDAY. THE UPPER LEVEL LOW AND
SURFACE LOW WILL BECOME NEARLY VERTICALLY STACKED OVER EASTERN
NORTH DAKOTA SUNDAY NIGHT. THIS WILL LEAD TO ENHANCED LIFT AND
PRECIPITATION ACROSS PORTIONS OF CENTRAL AND EASTERN NORTH DAKOTA.
AS THE LOW PROPAGATES EASTWARD SUNDAY NIGHT INTO MONDAY...COLD
AIR WILL WRAP IN FROM THE NORTH. A STEADY RAIN WILL TRANSITION TO
SNOW FROM NORTHWEST TO SOUTHEAST SUNDAY NIGHT. IN ADDITION TO
TRANSITIONING RAIN TO SNOW...STRONG COLD AIR ADVECTION AND A STEEP
PRESSURE GRADIENT WILL PRODUCE GUSTY NORTHWEST WINDS AROUND 35
MPH.
THE 12 UTC GFS/ECMWF/SREF/GEM ARE IN GOOD AGREEMENT WITH RESPECT
TO PRECIPITATION AMOUNTS AND TEMPERATURES. THEREFORE...UTILIZED A
BLEND OF THE OPERATIONAL MODELS. THIS GENERALLY YIELDED LIQUID
PRECIPITATION AMOUNTS AROUND HALF AN INCH AND SNOW AMOUNTS AROUND
1 OR 2 INCHES SUNDAY NIGHT INTO MONDAY. WITH TEMPERATURES HOVERING
NEAR FREEZING...ROAD TEMPERATURES COULD BE WARM ENOUGH TO LIMIT
NEGATIVE IMPACTS TO TRAVEL. FROST AND TEMPERATURES IN THE 20S AND
LOW 30S ARE LIKELY SUNDAY NIGHT AND MONDAY NIGHT.
FOR NORTH DAKOTA THE REST OF THE LONG TERM APPEARS COOL AND
DRY...WITH FREQUENT RAIN CHANCES ACROSS SOUTH DAKOTA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 340 PM CDT SAT MAY 16 2015
AT 230 PM CDT A WARM FRONT EXTENDED FROM A SURFACE LOW PRESSURE
CENTERED OVER NORTHWEST SOUTH DAKOTA WITH AN EAST WEST WARM FRONT
EXTENDING EAST ACROSS NORTH CENTRAL SOUTH DAKOTA. MOIST FLOW OVER
THE FRONT WILL MAINTAIN WIDESPREAD IFR KISN- KDIK-KBIS-KMOT WITH
MVFR CONDITIONS KJMS. THUNDERSTORMS WILL BECOME MORE NUMEROUS
LATE SATURDAY AFTERNOON AND EVENING EAST OF KBIS- KMOT LINE.
&&
.HYDROLOGY...
ISSUED AT 340 PM CDT SAT MAY 16 2015
FORECAST PRECIPITATION AMOUNTS THROUGH SUNDAY NIGHT RANGE BETWEEN
ONE AND TWO INCHES. CONFIDENCE IS LOW REGARDING TIMING AND
PLACEMENT OF RAIN SHOWERS AND THUNDERSTORMS...THUS AFFECTING
EXPECTED RAINFALL AMOUNTS. FUTURE FORECASTS MAY NEED TO INCLUDE AN
AREAL FLOOD WATCH...ESPECIALLY IF FORECAST CONFIDENCE INCREASES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...WAA
LONG TERM...AJ
AVIATION...WAA
HYDROLOGY...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1248 PM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 1239 PM CDT SAT MAY 16 2015
LAUNCHED AN 18Z SOUNDING IN SUPPORT OF THE SEVERE WEATHER
OPERATIONS THIS AFTERNOON AND EVENING. AT 1230 CDT A WARM FRONT
EXTENDED FROM A LOW IN SOUTHEAST MONTANA EAST THROUGH NORTH
CENTRAL SOUTH DAKOTA. FOCUSED THE HIGHEST POPS WEST CENTRAL INTO
THE NORTH WHERE BEST OVER RUNNING FLOW OVER THE WARM FRONT
CURRENTLY IS SPAWNING SHOWERS AND A FEW THUNDERSTORMS. RIGHT NOW
THE ACTIVITY IS ELEVATED WAND WEAK. WILL BE ANTICIPATING FURTHER
DEVELOPMENT NEXT FEW HOURS INTO THE EVENING CENTRAL MOVING INTO
THE JAMES RIVER VALLEY THIS EVENING.
UPDATE ISSUED AT 923 AM CDT SAT MAY 16 2015
VERY MOIST BOUNDARY LAYER AFTER OVERNIGHT RAINS. ACROSS THE SOUTHWEST
A SOUTHEAST UPSLOPE FLOW HAS RESULTED IN AREAS OF FOG AND LOW
CLOUDS. WILL ADD THIS TO THE FOREST THROUGH NOON. ELEVATED
CONVECTION ONGOING OVER THE LOW LEVELS SOUTHWEST SO KEPT A SLIGHT
CHANCE OF THUNDERSTORMS THERE. HOWEVER...DROPPED THE MENTION OF
THUNDERSTORMS THIS MORNING NORTH AND EAST BASED ON LATEST HRRR
CAPE FORECAST WHICH BASICALLY HOLDS OF THE THREAT OF THUNDER TIL
THIS AFTERNOON.
UPDATE ISSUED AT 615 AM CDT SAT MAY 16 2015
AT 615 AM CDT A LARGE AREA OF RAIN WAS MOVING NORTH FROM
DICKINSON...WITH SCATTERED SHOWERS FROM UNDERWOOD THROUGH
CARRINGTON. ANOTHER AREA OF SHOWERS WAS MOVING INTO OAKES. THE
NOSE OF THE NEXT BATCH OF RAIN WAS ADVANCING NORTH MIDWAY BETWEEN
RAPID CITY AND ABERDEEN SOUTH DAKOTA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 445 AM CDT SAT MAY 16 2015
MAIN CONCERNS IN THE SHORT TERM INCLUDE TIMING AND AREAL COVERAGE OF
RAIN SHOWERS AND THUNDERSTORMS...AND RESULTING PRECIP AMOUNTS ACROSS
WESTERN AND CENTRAL NORTH DAKOTA.
CHALLENGING FORECAST TODAY REGARDING TIMING AND COVERAGE/CHANCES OF
RAIN SHOWERS AND THUNDERSTORMS. THE HRRR HAD LOOKED THE BEST FOR
BRINGING RAIN SHOWERS NORTHWARD INTO NORTH DAKOTA FROM SOUTH
DAKOTA...BUT WITH TIME THIS MORNING THE NORTHWARD-MOVING LEADING
EDGE OF RAIN SHOWERS CONTINUED TO SLOW...AND NONE OF THE MODELS HAD
A GOOD HANDLE ON THE TIMING FROM FRIDAY EVENING THROUGH 4 AM CDT.
THAT SAID...THE CURRENT RADAR LOOPS DO INDICATE THE NORTHWARD
MOVEMENT OF THE PRECIPITATION...AND ALSO A MORE ROBUST LINE OF
THUNDERSTORMS OVER EASTERN SOUTH DAKOTA MOVING NORTHWARD.
THE MODELS INDICATE THE UPPER LEVEL AND LOW LEVEL LOW PRESSURE
CENTERS OVER WYOMING THIS MORNING. BY THIS EVENING THE UPPER LEVEL
LOW LIFTS NORTHWARD INTO MONTANA...BUT THE SURFACE LOW REMAINS OVER
WYOMING/SOUTH DAKOTA. ALL MODELS ARE SUGGESTING A CLEARING/DRYING
AREA DEVELOPING SOMEWHERE OVER SOUTH DAKOTA AND INTO SOUTHERN NORTH
DAKOTA...AND MODELS VARY ON WHETHER ITS PLACEMENT WILL BE IN THE
WESTERN DAKOTAS OR CENTRAL PARTS. DURING THE AFTERNOON IT IS
EXPECTED THAT THE INITIAL PUSH OF PRECIPITATION WILL LIFT NORTHWARD
TOWARDS CANADA...AND THAT THE CLEARING AREA TO THE SOUTH WILL ALLOW
ENHANCED SURFACE HEATING AND DEVELOPMENT OF A LINE OF THUNDERSTORMS
BY AROUND MID-AFTERNOON. CONFIDENCE IS LOW FOR HOW MUCH CLOUD COVER
WILL DISSIPATE AND WHETHER ANY LINE OF STRONG CONVECTION WILL
DEVELOP. REGARDLESS...FORECAST CAPES AND BULK SHEAR SUPPORT
THE POSSIBILITY OF SEVERE STORMS THIS AFTERNOON/EVENING...MAINLY
OVER CENTRAL NORTH DAKOTA.
TOTAL RAIN AMOUNTS THROUGH SATURDAY NIGHT RANGE FROM AROUND 0.5
INCH TO 1.25 INCHES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 445 AM CDT SAT MAY 16 2015
NOTE...WITH THE RISK OF SEVERE WEATHER TODAY IT WOULD NOT BE
PRUDENT TO POST ANY WIND...WINTER...OR FROST / FREEZE HEADLINES AT
THIS TIME AS IT WOULD LEAD TO CONFUSE THE ISSUES. I DO EXPECT THE
NEED FOR A WIND ADVISORY...WINTER WEATHER ADVISORY (NORTHEAST
FORECAST AREA)...AND FROST ADVISORY / FREEZE WARNING...AT VARIOUS
POINTS OVER THE NEXT SEVERAL DAYS.
FORECAST CHALLENGES AND HAZARDS CONTINUE INTO THE LONG TERM. THEY
INCLUDE THUNDER...HEAVY RAIN...SNOW...AND TEMPERATURES IN THE 20S.
AS WE TRANSITION SUNDAY FROM POCKETS OF INSTABILITY TO A GENERAL
WIDESPREAD LIFTING...THE RISK OF THUNDERSTORMS WILL BE CONFINED
TO THE JAMES RIVER VALLEY. FOR THE REST OF THE AREA A STEADY
RAIN...HEAVY AT TIMES AS THE H5 LOW APPROACHES...WILL OCCUR.
COLDER AIR WORKS IN ON STRONG NORTHWEST WINDS 25 TO 45 MPH AND BY
SUNDAY EVENING THE RAIN NORTH WILL BE MIXING WITH SNOW. WITH H8
TEMPERATURES FALLING TO -4 DEGREES C THE MIX WILL CHANGE TO ALL
SNOW NORTH...WITH A MIX SOUTH. RUNNING THE QUANTITATIVE
PRECIPITATION FORECAST ALONG WITH SNOW RATIOS OFF THE NAM (THE
MOST REASONABLE BASED ON EXPECTED THERMAL PROFILES) A FEW TO
SEVERAL INCHES OF SNOW RESULTS FROM BOTTINEAU COUNTY THROUGH
ROLETTE AND DOWN INTO NORTHERN PIERCE...THAT ON GRASSY SURFACES.
EVEN UNDER CLOUD COVER DAYBREAK TEMPERATURES MONDAY MORNING WILL
BE WITHIN SEVERAL DEGREES EITHER SIDE OF FREEZING. BY MID DAY
MONDAY THE PRECIPITATION ENDS OVER THE FORECAST AREA BUT THE
STRONG NORTHWEST WINDS CONTINUE.
WITH PARTLY CLOUDY SKIES MONDAY NIGHT LOWS ARE FORECAST TO BE IN
THE 27 TO 34 DEGREE RANGE.
BEYOND THAT THE STORM TRACK SHIFTS SOUTH...OVER NEBRASKA AND SOUTH
DAKOTA WITH THE NORTHERN EXTENT OF THE PRECIPITATION
EXTENDING...PERIODICALLY...INTO SOUTHERN NORTH DAKOTA. THROUGH
THE REST OF THE LONG TERM INSTABILITY AND CAPE ARE VERY LIMITED SO
OPTED TO NOT INCLUDE THUNDER IN ANY PERIOD BEYOND SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1239 PM CDT SAT MAY 16 2015
AT 1230 PM CDT A WARM FRONT EXTENDED FROM A SURFACE LOW PRESSURE
CENTERED OVER SOUTHEAST MONTANA WITH A WARM FRONT EXTENDING EAST
ACROSS NORTH CENTRAL SOUTH DAKOTA. MOIST FLOW OVER THE FRONT WILL
MAINTAIN WIDESPREAD IFR KISN- KDIK-KBIS WITH MVFR CONDITIONS
KMOT- KJMS. CONDITIONS GENERALLY BECOMING MVFR LATE SATURDAY
AFTERNOON. THUNDERSTORMS WILL BECOME MORE NUMEROUS LATE SATURDAY
AFTERNOON AND EVENING EAST OF KBIS-KMOT LINE.
&&
.HYDROLOGY...
ISSUED AT 445 AM CDT SAT MAY 16 2015
FORECAST PRECIPITATION AMOUNTS THROUGH SUNDAY NIGHT RANGE BETWEEN
ONE AND THREE INCHES. CONFIDENCE IS LOW REGARDING TIMING AND
PLACEMENT OF RAIN SHOWERS AND THUNDERSTORMS...THUS AFFECTING
EXPECTED RAINFALL AMOUNTS. FUTURE FORECASTS MAY NEED TO INCLUDE AN
AREAL FLOOD WATCH...ESPECIALLY IF FORECAST CONFIDENCE INCREASES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...JV
LONG TERM...JPM
AVIATION...WAA
HYDROLOGY...JV/JPM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
936 AM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 923 AM CDT SAT MAY 16 2015
VERY MOIST BOUNDARY LAYER AFTER OVERNIGHT RAINS. ACROSS THE SOUTHWEST
A SOUTHEAST UPSLOPE FLOW HAS RESULTED IN AREAS OF FOG AND LOW
CLOUDS. WILL ADD THIS TO THE FOREST THROUGH NOON. ELEVATED
CONVECTION ONGOING OVER THE LOW LEVELS SOUTHWEST SO KEPT A SLIGHT
CHANCE OF THUNDERSTORMS THERE. HOWEVER...DROPPED THE MENTION OF
THUNDERSTORMS THIS MORNING NORTH AND EAST BASED ON LATEST HRRR
CAPE FORECAST WHICH BASICALLY HOLDS OF THE THREAT OF THUNDER TIL
THIS AFTERNOON.
UPDATE ISSUED AT 615 AM CDT SAT MAY 16 2015
AT 615 AM CDT A LARGE AREA OF RAIN WAS MOVING NORTH FROM
DICKINSON...WITH SCATTERED SHOWERS FROM UNDERWOOD THROUGH
CARRINGTON. ANOTHER AREA OF SHOWERS WAS MOVING INTO OAKES. THE
NOSE OF THE NEXT BATCH OF RAIN WAS ADVANCING NORTH MIDWAY BETWEEN
RAPID CITY AND ABERDEEN SOUTH DAKOTA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 445 AM CDT SAT MAY 16 2015
MAIN CONCERNS IN THE SHORT TERM INCLUDE TIMING AND AREAL COVERAGE OF
RAIN SHOWERS AND THUNDERSTORMS...AND RESULTING PRECIP AMOUNTS ACROSS
WESTERN AND CENTRAL NORTH DAKOTA.
CHALLENGING FORECAST TODAY REGARDING TIMING AND COVERAGE/CHANCES OF
RAIN SHOWERS AND THUNDERSTORMS. THE HRRR HAD LOOKED THE BEST FOR
BRINGING RAIN SHOWERS NORTHWARD INTO NORTH DAKOTA FROM SOUTH
DAKOTA...BUT WITH TIME THIS MORNING THE NORTHWARD-MOVING LEADING
EDGE OF RAIN SHOWERS CONTINUED TO SLOW...AND NONE OF THE MODELS HAD
A GOOD HANDLE ON THE TIMING FROM FRIDAY EVENING THROUGH 4 AM CDT.
THAT SAID...THE CURRENT RADAR LOOPS DO INDICATE THE NORTHWARD
MOVEMENT OF THE PRECIPITATION...AND ALSO A MORE ROBUST LINE OF
THUNDERSTORMS OVER EASTERN SOUTH DAKOTA MOVING NORTHWARD.
THE MODELS INDICATE THE UPPER LEVEL AND LOW LEVEL LOW PRESSURE
CENTERS OVER WYOMING THIS MORNING. BY THIS EVENING THE UPPER LEVEL
LOW LIFTS NORTHWARD INTO MONTANA...BUT THE SURFACE LOW REMAINS OVER
WYOMING/SOUTH DAKOTA. ALL MODELS ARE SUGGESTING A CLEARING/DRYING
AREA DEVELOPING SOMEWHERE OVER SOUTH DAKOTA AND INTO SOUTHERN NORTH
DAKOTA...AND MODELS VARY ON WHETHER ITS PLACEMENT WILL BE IN THE
WESTERN DAKOTAS OR CENTRAL PARTS. DURING THE AFTERNOON IT IS
EXPECTED THAT THE INITIAL PUSH OF PRECIPITATION WILL LIFT NORTHWARD
TOWARDS CANADA...AND THAT THE CLEARING AREA TO THE SOUTH WILL ALLOW
ENHANCED SURFACE HEATING AND DEVELOPMENT OF A LINE OF THUNDERSTORMS
BY AROUND MID-AFTERNOON. CONFIDENCE IS LOW FOR HOW MUCH CLOUD COVER
WILL DISSIPATE AND WHETHER ANY LINE OF STRONG CONVECTION WILL
DEVELOP. REGARDLESS...FORECAST CAPES AND BULK SHEAR SUPPORT
THE POSSIBILITY OF SEVERE STORMS THIS AFTERNOON/EVENING...MAINLY
OVER CENTRAL NORTH DAKOTA.
TOTAL RAIN AMOUNTS THROUGH SATURDAY NIGHT RANGE FROM AROUND 0.5
INCH TO 1.25 INCHES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 445 AM CDT SAT MAY 16 2015
NOTE...WITH THE RISK OF SEVERE WEATHER TODAY IT WOULD NOT BE
PRUDENT TO POST ANY WIND...WINTER...OR FROST / FREEZE HEADLINES AT
THIS TIME AS IT WOULD LEAD TO CONFUSE THE ISSUES. I DO EXPECT THE
NEED FOR A WIND ADVISORY...WINTER WEATHER ADVISORY (NORTHEAST
FORECAST AREA)...AND FROST ADVISORY / FREEZE WARNING...AT VARIOUS
POINTS OVER THE NEXT SEVERAL DAYS.
FORECAST CHALLENGES AND HAZARDS CONTINUE INTO THE LONG TERM. THEY
INCLUDE THUNDER...HEAVY RAIN...SNOW...AND TEMPERATURES IN THE 20S.
AS WE TRANSITION SUNDAY FROM POCKETS OF INSTABILITY TO A GENERAL
WIDESPREAD LIFTING...THE RISK OF THUNDERSTORMS WILL BE CONFINED
TO THE JAMES RIVER VALLEY. FOR THE REST OF THE AREA A STEADY
RAIN...HEAVY AT TIMES AS THE H5 LOW APPROACHES...WILL OCCUR.
COLDER AIR WORKS IN ON STRONG NORTHWEST WINDS 25 TO 45 MPH AND BY
SUNDAY EVENING THE RAIN NORTH WILL BE MIXING WITH SNOW. WITH H8
TEMPERATURES FALLING TO -4 DEGREES C THE MIX WILL CHANGE TO ALL
SNOW NORTH...WITH A MIX SOUTH. RUNNING THE QUANTITATIVE
PRECIPITATION FORECAST ALONG WITH SNOW RATIOS OFF THE NAM (THE
MOST REASONABLE BASED ON EXPECTED THERMAL PROFILES) A FEW TO
SEVERAL INCHES OF SNOW RESULTS FROM BOTTINEAU COUNTY THROUGH
ROLETTE AND DOWN INTO NORTHERN PIERCE...THAT ON GRASSY SURFACES.
EVEN UNDER CLOUD COVER DAYBREAK TEMPERATURES MONDAY MORNING WILL
BE WITHIN SEVERAL DEGREES EITHER SIDE OF FREEZING. BY MID DAY
MONDAY THE PRECIPITATION ENDS OVER THE FORECAST AREA BUT THE
STRONG NORTHWEST WINDS CONTINUE.
WITH PARTLY CLOUDY SKIES MONDAY NIGHT LOWS ARE FORECAST TO BE IN
THE 27 TO 34 DEGREE RANGE.
BEYOND THAT THE STORM TRACK SHIFTS SOUTH...OVER NEBRASKA AND SOUTH
DAKOTA WITH THE NORTHERN EXTENT OF THE PRECIPITATION
EXTENDING...PERIODICALLY...INTO SOUTHERN NORTH DAKOTA. THROUGH
THE REST OF THE LONG TERM INSTABILITY AND CAPE ARE VERY LIMITED SO
OPTED TO NOT INCLUDE THUNDER IN ANY PERIOD BEYOND SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 923 AM CDT SAT MAY 16 2015
AT 930 AM CDT A SURFACE LOW PRESSURE WAS CENTERED OVER SOUTHEAST
MONTANA WITH A WARM FRONT EXTENDED EAST ACROSS CENTRAL SOUTH
DAKOTA. MOIST FLOW OVER THE FRONT WILL MAINTAIN WIDESPREAD IFR
KISN- KDIK-KBIS WITH MVFR CONDITIONS KMOT-KJMS THROUGH NOON. LOW
LEVEL UPSLOPE FLOW ACROSS THE SOUTHWEST WILL RESULT IN VERY LOW
IFR CONDITIONS IN FOG AT KDIK THROUGH 17Z. CONDITIONS GENERALLY
BECOMING MVFR SATURDAY AFTERNOON. THUNDERSTORMS WILL BECOME MORE
NUMEROUS LATE SATURDAY AFTERNOON AND EVENING EAST OF KBIS-KMOT
LINE.
&&
.HYDROLOGY...
ISSUED AT 445 AM CDT SAT MAY 16 2015
FORECAST PRECIPITATION AMOUNTS THROUGH SUNDAY NIGHT RANGE BETWEEN
ONE AND THREE INCHES. CONFIDENCE IS LOW REGARDING TIMING AND
PLACEMENT OF RAIN SHOWERS AND THUNDERSTORMS...THUS AFFECTING
EXPECTED RAINFALL AMOUNTS. FUTURE FORECASTS MAY NEED TO INCLUDE AN
AREAL FLOOD WATCH...ESPECIALLY IF FORECAST CONFIDENCE INCREASES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...JV
LONG TERM...JPM
AVIATION...WAA
HYDROLOGY...JV/JPM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
623 AM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 615 AM CDT SAT MAY 16 2015
AT 615 AM CDT A LARGE AREA OF RAIN WAS MOVING NORTH FROM
DICKINSON...WITH SCATTERED SHOWERS FROM UNDERWOOD THROUGH
CARRINGTON. ANOTHER AREA OF SHOWERS WAS MOVING INTO OAKES. THE
NOSE OF THE NEXT BATCH OF RAIN WAS ADVANCING NORTH MIDWAY BETWEEN
RAPID CITY AND ABERDEEN SOUTH DAKOTA.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 445 AM CDT SAT MAY 16 2015
MAIN CONCERNS IN THE SHORT TERM INCLUDE TIMING AND AREAL COVERAGE OF
RAIN SHOWERS AND THUNDERSTORMS...AND RESULTING PRECIP AMOUNTS ACROSS
WESTERN AND CENTRAL NORTH DAKOTA.
CHALLENGING FORECAST TODAY REGARDING TIMING AND COVERAGE/CHANCES OF
RAIN SHOWERS AND THUNDERSTORMS. THE HRRR HAD LOOKED THE BEST FOR
BRINGING RAIN SHOWERS NORTHWARD INTO NORTH DAKOTA FROM SOUTH
DAKOTA...BUT WITH TIME THIS MORNING THE NORTHWARD-MOVING LEADING
EDGE OF RAIN SHOWERS CONTINUED TO SLOW...AND NONE OF THE MODELS HAD
A GOOD HANDLE ON THE TIMING FROM FRIDAY EVENING THROUGH 4 AM CDT.
THAT SAID...THE CURRENT RADAR LOOPS DO INDICATE THE NORTHWARD
MOVEMENT OF THE PRECIPITATION...AND ALSO A MORE ROBUST LINE OF
THUNDERSTORMS OVER EASTERN SOUTH DAKOTA MOVING NORTHWARD.
THE MODELS INDICATE THE UPPER LEVEL AND LOW LEVEL LOW PRESSURE
CENTERS OVER WYOMING THIS MORNING. BY THIS EVENING THE UPPER LEVEL
LOW LIFTS NORTHWARD INTO MONTANA...BUT THE SURFACE LOW REMAINS OVER
WYOMING/SOUTH DAKOTA. ALL MODELS ARE SUGGESTING A CLEARING/DRYING
AREA DEVELOPING SOMEWHERE OVER SOUTH DAKOTA AND INTO SOUTHERN NORTH
DAKOTA...AND MODELS VARY ON WHETHER ITS PLACEMENT WILL BE IN THE
WESTERN DAKOTAS OR CENTRAL PARTS. DURING THE AFTERNOON IT IS
EXPECTED THAT THE INITIAL PUSH OF PRECIPITATION WILL LIFT NORTHWARD
TOWARDS CANADA...AND THAT THE CLEARING AREA TO THE SOUTH WILL ALLOW
ENHANCED SURFACE HEATING AND DEVELOPMENT OF A LINE OF THUNDERSTORMS
BY AROUND MID-AFTERNOON. CONFIDENCE IS LOW FOR HOW MUCH CLOUD COVER
WILL DISSIPATE AND WHETHER ANY LINE OF STRONG CONVECTION WILL
DEVELOP. REGARDLESS...FORECAST CAPES AND BULK SHEAR SUPPORT
THE POSSIBILITY OF SEVERE STORMS THIS AFTERNOON/EVENING...MAINLY
OVER CENTRAL NORTH DAKOTA.
TOTAL RAIN AMOUNTS THROUGH SATURDAY NIGHT RANGE FROM AROUND 0.5
INCH TO 1.25 INCHES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 445 AM CDT SAT MAY 16 2015
NOTE...WITH THE RISK OF SEVERE WEATHER TODAY IT WOULD NOT BE
PRUDENT TO POST ANY WIND...WINTER...OR FROST / FREEZE HEADLINES AT
THIS TIME AS IT WOULD LEAD TO CONFUSE THE ISSUES. I DO EXPECT THE
NEED FOR A WIND ADVISORY...WINTER WEATHER ADVISORY (NORTHEAST
FORECAST AREA)...AND FROST ADVISORY / FREEZE WARNING...AT VARIOUS
POINTS OVER THE NEXT SEVERAL DAYS.
FORECAST CHALLENGES AND HAZARDS CONTINUE INTO THE LONG TERM. THEY
INCLUDE THUNDER...HEAVY RAIN...SNOW...AND TEMPERATURES IN THE 20S.
AS WE TRANSITION SUNDAY FROM POCKETS OF INSTABILITY TO A GENERAL
WIDESPREAD LIFTING...THE RISK OF THUNDERSTORMS WILL BE CONFINED
TO THE JAMES RIVER VALLEY. FOR THE REST OF THE AREA A STEADY
RAIN...HEAVY AT TIMES AS THE H5 LOW APPROACHES...WILL OCCUR.
COLDER AIR WORKS IN ON STRONG NORTHWEST WINDS 25 TO 45 MPH AND BY
SUNDAY EVENING THE RAIN NORTH WILL BE MIXING WITH SNOW. WITH H8
TEMPERATURES FALLING TO -4 DEGREES C THE MIX WILL CHANGE TO ALL
SNOW NORTH...WITH A MIX SOUTH. RUNNING THE QUANTITATIVE
PRECIPITATION FORECAST ALONG WITH SNOW RATIOS OFF THE NAM (THE
MOST REASONABLE BASED ON EXPECTED THERMAL PROFILES) A FEW TO
SEVERAL INCHES OF SNOW RESULTS FROM BOTTINEAU COUNTY THROUGH
ROLETTE AND DOWN INTO NORTHERN PIERCE...THAT ON GRASSY SURFACES.
EVEN UNDER CLOUDCOVER DAYBREAK TEMPERATURES MONDAY MORNING WILL BE
WITHIN SEVERAL DEGREES EITHER SIDE OF FREEZING. BY MID DAY MONDAY
THE PRECIPITATION ENDS OVER THE FORECAST AREA BUT THE STRONG
NORTHWEST WINDS CONTINUE.
WITH PARTLY CLOUDY SKIES MONDAY NIGHT LOWS ARE FORECAST TO BE IN
THE 27 TO 34 DEGREE RANGE.
BEYOND THAT THE STORM TRACK SHIFTS SOUTH...OVER NEBRASKA AND SOUTH
DAKOTA WITH THE NORTHERN EXTENT OF THE PRECIPITATION
EXTENDING...PERIODICALLY...INTO SOUTHERN NORTH DAKOTA. THROUGH
THE REST OF THE LONG TERM INSTABILITY AND CAPE ARE VERY LIMITED SO
OPTED TO NOT INCLUDE THUNDER IN ANY PERIOD BEYOND SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 615 AM CDT SAT MAY 16 2015
THE MAIN CONCERN IS THE SHOWER / THUNDERSTORM CHANCES AND THE
ASSOCIATED MVFR CEILINGS / VISIBILITIES. EXPECT INCREASING
CHANCES FOR SHOWERS THROUGH THE DAY...WITH INCREASING CHANCES FOR
THUNDERSTORMS ESPECIALLY CENTRAL AND EASTERN NORTH DAKOTA TAF
SITES. AFTER 03Z ON THE 17TH THUNDER CHANCES WILL DECREASE AS
WIDESPREAD RAIN MOVES IN WITH MVFR CONDITIONS.
&&
.HYDROLOGY...
ISSUED AT 445 AM CDT SAT MAY 16 2015
FORECAST PRECIPITATION AMOUNTS THROUGH SUNDAY NIGHT RANGE BETWEEN
ONE AND THREE INCHES. CONFIDENCE IS LOW REGARDING TIMING AND
PLACEMENT OF RAIN SHOWERS AND THUNDERSTORMS...THUS AFFECTING
EXPECTED RAINFALL AMOUNTS. FUTURE FORECASTS MAY NEED TO INCLUDE AN
AREAL FLOOD WATCH...ESPECIALLY IF FORECAST CONFIDENCE INCREASES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JPM
SHORT TERM...JV
LONG TERM...JPM
AVIATION...JV/JPM
HYDROLOGY...JV/JPM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
455 AM CDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 445 AM CDT SAT MAY 16 2015
MAIN CONCERNS IN THE SHORT TERM INCLUDE TIMING AND AREAL COVERAGE OF
RAIN SHOWERS AND THUNDERSTORMS...AND RESULTING PRECIP AMOUNTS ACROSS
WESTERN AND CENTRAL NORTH DAKOTA.
CHALLENGING FORECAST TODAY REGARDING TIMING AND COVERAGE/CHANCES OF
RAIN SHOWERS AND THUNDERSTORMS. THE HRRR HAD LOOKED THE BEST FOR
BRINGING RAIN SHOWERS NORTHWARD INTO NORTH DAKOTA FROM SOUTH
DAKOTA...BUT WITH TIME THIS MORNING THE NORTHWARD-MOVING LEADING
EDGE OF RAIN SHOWERS CONTINUED TO SLOW...AND NONE OF THE MODELS HAD
A GOOD HANDLE ON THE TIMING FROM FRIDAY EVENING THROUGH 4 AM CDT.
THAT SAID...THE CURRENT RADAR LOOPS DO INDICATE THE NORTHWARD
MOVEMENT OF THE PRECIPITATION...AND ALSO A MORE ROBUST LINE OF
THUNDERSTORMS OVER EASTERN SOUTH DAKOTA MOVING NORTHWARD.
THE MODELS INDICATE THE UPPER LEVEL AND LOW LEVEL LOW PRESSURE
CENTERS OVER WYOMING THIS MORNING. BY THIS EVENING THE UPPER LEVEL
LOW LIFTS NORTHWARD INTO MONTANA...BUT THE SURFACE LOW REMAINS OVER
WYOMING/SOUTH DAKOTA. ALL MODELS ARE SUGGESTING A CLEARING/DRYING
AREA DEVELOPING SOMEWHERE OVER SOUTH DAKOTA AND INTO SOUTHERN NORTH
DAKOTA...AND MODELS VARY ON WHETHER ITS PLACEMENT WILL BE IN THE
WESTERN DAKOTAS OR CENTRAL PARTS. DURING THE AFTERNOON IT IS
EXPECTED THAT THE INITIAL PUSH OF PRECIPITATION WILL LIFT NORTHWARD
TOWARDS CANADA...AND THAT THE CLEARING AREA TO THE SOUTH WILL ALLOW
ENHANCED SURFACE HEATING AND DEVELOPMENT OF A LINE OF THUNDERSTORMS
BY AROUND MID-AFTERNOON. CONFIDENCE IS LOW FOR HOW MUCH CLOUD COVER
WILL DISSIPATE AND WHETHER ANY LINE OF STRONG CONVECTION WILL
DEVELOP. REGARDLESS...FORECAST CAPES AND BULK SHEAR SUPPORT
THE POSSIBILITY OF SEVERE STORMS THIS AFTERNOON/EVENING...MAINLY
OVER CENTRAL NORTH DAKOTA.
TOTAL RAIN AMOUNTS THROUGH SATURDAY NIGHT RANGE FROM AROUND 0.5
INCH TO 1.25 INCHES.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 445 AM CDT SAT MAY 16 2015
NOTE...WITH THE RISK OF SEVERE WEATHER TODAY IT WOULD NOT BE
PRUDENT TO POST ANY WIND...WINTER...OR FROST / FREEZE HEADLINES AT
THIS TIME AS IT WOULD LEAD TO CONFUSE THE ISSUES. I DO EXPECT THE
NEED FOR A WIND ADVISORY...WINTER WEATHER ADVISORY (NORTHEAST
FORECAST AREA)...AND FROST ADVISORY / FREEZE WARNING...AT VARIOUS
POINTS OVER THE NEXT SEVERAL DAYS.
FORECAST CHALLENGES AND HAZARDS CONTINUE INTO THE LONG TERM. THEY
INCLUDE THUNDER...HEAVY RAIN...SNOW...AND TEMPERATURES IN THE 20S.
AS WE TRANSITION SUNDAY FROM POCKETS OF INSTABILITY TO A GENERAL
WIDESPREAD LIFTING...THE RISK OF THUNDERSTORMS WILL BE CONFINED
TO THE JAMES RIVER VALLEY. FOR THE REST OF THE AREA A STEADY
RAIN...HEAVY AT TIMES AS THE H5 LOW APPROACHES...WILL OCCUR.
COLDER AIR WORKS IN ON STRONG NORTHWEST WINDS 25 TO 45 MPH AND BY
SUNDAY EVENING THE RAIN NORTH WILL BE MIXING WITH SNOW. WITH H8
TEMPERATURES FALLING TO -4 DEGREES C THE MIX WILL CHANGE TO ALL
SNOW NORTH...WITH A MIX SOUTH. RUNNING THE QUANTITATIVE
PRECIPITATION FORECAST ALONG WITH SNOW RATIOS OFF THE NAM (THE
MOST REASONABLE BASED ON EXPECTED THERMAL PROFILES) A FEW TO
SEVERAL INCHES OF SNOW RESULTS FROM BOTTINEAU COUNTY THROUGH
ROLETTE AND DOWN INTO NORTHERN PIERCE...THAT ON GRASSY SURFACES.
EVEN UNDER CLOUDCOVER DAYBREAK TEMPERATURES MONDAY MORNING WILL BE
WITHIN SEVERAL DEGREES EITHER SIDE OF FREEZING. BY MID DAY MONDAY
THE PRECIPITATION ENDS OVER THE FORECAST AREA BUT THE STRONG
NORTHWEST WINDS CONTINUE.
WITH PARTLY CLOUDY SKIES MONDAY NIGHT LOWS ARE FORECAST TO BE IN
THE 27 TO 34 DEGREE RANGE.
BEYOND THAT THE STORM TRACK SHIFTS SOUTH...OVER NEBRASKA AND SOUTH
DAKOTA WITH THE NORTHERN EXTENT OF THE PRECIPITATION
EXTENDING...PERIODICALLY...INTO SOUTHERN NORTH DAKOTA. THROUGH
THE REST OF THE LONG TERM INSTABILITY AND CAPE ARE VERY LIMITED SO
OPTED TO NOT INCLUDE THUNDER IN ANY PERIOD BEYOND SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 445 AM CDT SAT MAY 16 2015
THE MAIN CONCERN WILL BE THE RAIN / THUNDERSTORM CHANCES AND THE
ASSOCIATED DECREASE IN CEILINGS / VISIBILITIES. RAIN WILL LIFT
NORTH BRINGING A CHANCE OF SHOWERS AND PERHAPS A FEW THUNDERSTORMS
TO THE TERMINALS THIS MORNING. CEILINGS WILL LOWER AS THE RAIN
MOVES INTO THE REGION.
THERE COULD BE A BRIEF BREAK IN THE RAIN AS IT LIFTS FROM SOUTH
TO NORTH ON SATURDAY. IF THERE IS A BREAK...IT WILL LIKELY BE
SHORT LIVED WITH SHOWERS AND THUNDERSTORMS DEVELOPING AGAIN
SATURDAY AFTERNOON AND NIGHT. CHANCES ARE BETTER SATURDAY AFTERNOON
AND EVENING FOR THUNDER.
&&
.HYDROLOGY...
ISSUED AT 445 AM CDT SAT MAY 16 2015
FORECAST PRECIPITATION AMOUNTS THROUGH SUNDAY NIGHT RANGE BETWEEN
ONE AND THREE INCHES. CONFIDENCE IS LOW REGARDING TIMING AND
PLACEMENT OF RAIN SHOWERS AND THUNDERSTORMS...THUS AFFECTING
EXPECTED RAINFALL AMOUNTS. FUTURE FORECASTS MAY NEED TO INCLUDE AN
AREAL FLOOD WATCH...ESPECIALLY IF FORECAST CONFIDENCE INCREASES.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JV
LONG TERM...JPM
AVIATION...JV
HYDROLOGY...JV/JPM
AREA FORECAST DISCUSSION
NWS BISMARCK ND
115 AM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 114 AM CDT SAT MAY 16 2015
MAIN UPDATE TO THE FORECAST WAS TO SLOW THE ONSET OF PRECIPITATION
IN THE SOUTHWEST. THOUGH IT IS RAINING IN HETTINGER...THE LEADING
EDGE OF RAIN SHOWERS HAD NOT YET REACHED DICKINSON OR GRANT OR SIOUX
COUNTY. THE LATEST HRRR MODEL WAS HANDLING THE CURRENT PRECIPITATION
AREA WELL...SO BACKED OFF ON PRECIP CHANCES NORTH AND EAST FOR EARLY
THIS MORNING AND INCREASED CHANCES AFTER AROUND 3 AM CDT. OTHERWISE
FORECAST ON TRACK FOR THE OVERNIGHT HOURS.
UPDATE ISSUED AT 946 PM CDT FRI MAY 15 2015
MAIN UPDATE TO THE FORECAST THIS EVENING WAS TO SPREAD THE
POSSIBILITY OF ISOLATED THUNDERSTORMS INTO THE WESTERN PART OF THE
STATE. FORECAST MUCAPE FROM THE RAP SHOWS WEAK INSTABILITY FROM
WESTERN INTO SOUTH CENTRAL NORTH DAKOTA OVERNIGHT. CURRENT RADAR
MOSAIC INDICATES SHOWERS AND THUNDERSTORMS IN WESTERN SOUTH DAKOTA
CONTINUE TO MOVE NORTH...WHICH IS WELL COVERED IN THE FORECAST
WITH HIGH POPS IN PLACE OVERNIGHT. DECIDED TO ISSUE THE SPECIAL
WEATHER STATEMENT (SPS) AGAIN TO HIGHLIGHT THE ACTIVE WEATHER IN
THE FORECAST FOR THIS WEEKEND.
UPDATE ISSUED AT 645 PM CDT FRI MAY 15 2015
REGIONAL RADAR MOSAIC SHOWERS A FEW LIGHT SHOWERS MOVING ACROSS
WESTERN NORTH DAKOTA INTO EASTERN MONTANA. FARTHER
SOUTH...THUNDERSTORMS WERE LIFTING NORTH ACROSS PARTS OF WESTERN
SOUTH DAKOTA. THE LATEST HRRR AND RAP SUGGEST IT WILL TAKE A
FEW MORE HOURS BEFORE THE MAIN AREA OF RAIN IN SOUTH DAKOTA
REACHES THE SOUTHWEST PART OF THE STATE. THE HRRR ALSO SUGGESTS
THERE COULD BE A FEW ISOLATED SHOWERS IN ADVANCE OF THE MAIN AREA
OF RAIN...SO DID NOT REMOVE POPS ALTOGETHER IN THE NEAR TERM...BUT
DID DECREASE THEM TO SOME DEGREE EARLY THIS EVENING. MADE MINOR
ADJUSTMENTS TO SKY COVER AND TEMPERATURES...BUT OVERALL THE
REMAINDER OF THE FORECAST LOOKS ON TRACK.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 303 PM CDT FRI MAY 15 2015
MAIN ISSUES IN THE SHORT TERM ARE TIMING THE START OF
PRECIPITATION THIS EVENING AND POSSIBLE SEVERE THUNDERSTORMS
SATURDAY. MODELS AND RADAR SHOWING SLOWER TRENDS OF PRECIPITATION SO
WILL DELAY THE ONSET OF PRECIP ACROSS THE SOUTH CENTRAL AND JAMES
RIVER VALLEY TO MID TO LATE EVENING. NAM/GFS BOTH HAVE A FAIRLY
GOOD CAP LOWER LEVELS. THERE IS SOME ELEVATED CAPE THIS EVENING AND
OVERNIGHT SO REFINED THE THREAT OF NON SEVERE THUNDERSTORMS
TONIGHT TO JUST THE SOUTH CENTRAL AND AFTER 9 PM CDT. ON SATURDAY
LOOKING FRO A MORE SIGNIFICANT SHORTWAVE TROUGH SUPPORTING
THUNDERSTORMS. BEST CAPE REMAINS SOUTH CENTRAL WITH THE JAMES
RIVER VALLEY MORE CAPPED TRENDING TO TALL SKINNY CAPE BY EVENING.
THIS WOULD LEND LESS SUPPORT TO SEVERE MORE TO MODERATE RAIN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 303 PM CDT FRI MAY 15 2015
VERY ACTIVE WEATHER WILL OCCUR OVER THE WEEKEND WITH NUMEROUS
IMPACTS AS A STRONG STORM SYSTEM CROSSES THE NORTHERN PLAINS.
INITIALLY...SEVERE THUNDERSTORMS WILL BE THE THREAT SATURDAY
EVENING...THOUGH SURFACE BASED INSTABILITY WILL DIMINISH WHILE
PROFILES SATURATE PER FORECAST SOUNDINGS. MEANWHILE A STRONG 100KT
JET WILL BEGIN NOSING INTO THE DAKOTAS AND HELP DEEPEN THE CUT OFF
UPPER LOW WHICH IS LOCATED OVER SOUTH DAKOTA AT 12Z SUNDAY.
DEEP SURFACE LOW REACHES SOUTHEASTERN NORTH DAKOTA BY 00Z MON WITH
STRONG SURFACE PRESSURE GRADIENT ACROSS THE STATE...26MB CHANGE FROM
NORTHWEST ND TO THE SOUTHEAST PART OF THE STATE PER GFS. SUB-
FREEZING 850MB TEMPS DROP SOUTHWARD INTO CENTRAL NORTH DAKOTA...WITH
SOUNDINGS SUPPORTING A CHANGEOVER OF RAIN TO SNOW LATE SUNDAY/SUNDAY
NIGHT. WPC WINTER WEATHER DESK SHOWS AMOUNTS AROUND 2-4 INCHES
ACROSS THE NORTH. TRAVEL COULD BECOME HAZARDOUS IN SOME AREAS WITH
COMBINATION OF STRONG WIND AND SNOW. BY MID-DAY MONDAY THE LOW
CENTER REACHES THE GREAT LAKES WITH HIGH PRESSURE BUILDING ACROSS
THE STATE. MAX TEMPS WILL GRADUALLY MODERATE TO THE 50S AND 60S BY
WED/THU.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 114 AM CDT SAT MAY 16 2015
THE MAIN CONCERN WILL BE THE RAIN / THUNDERSTORM CHANCES AND THE
ASSOCIATED DECREASE IN CEILINGS / VISIBILITIES. RAIN ACROSS SOUTH
DAKOTA WILL LIFT NORTH BRINGING A CHANCE OF SHOWERS AND PERHAPS A
FEW THUNDERSTORMS TO THE TERMINALS THIS MORNING. CEILINGS WILL LOWER
AS THE RAIN MOVES INTO THE REGION.
THERE COULD BE A BRIEF BREAK IN THE RAIN AS IT LIFTS FROM SOUTH
TO NORTH ON SATURDAY. IF THERE IS A BREAK...IT WILL LIKELY BE
SHORT LIVED WITH SHOWERS AND THUNDERSTORMS DEVELOPING AGAIN
SATURDAY AFTERNOON AND NIGHT. CHANCES ARE BETTER SATURDAY AFTERNOON
AND EVENING FOR THUNDER.
&&
.HYDROLOGY...
ISSUED AT 303 PM CDT FRI MAY 15 2015
ENSEMBLE SITUATIONAL AWARENESS TABLE SHOWS PRECIPITABLE WATER
OVER OUR AREA AROUND 90TH PERCENTILE FROM SATURDAY INTO SUNDAY
AFTERNOON. FORECAST PRECIP AMOUNTS THROUGH 00Z MONDAY RANGE FROM
AROUND 0.75 INCHES OVER SOUTHWESTERN ND TO 2+ INCHES...MAINLY
NORTH AND EAST. CONTEMPLATED AN AREAL FLOOD WATCH...BUT THE
HEAVIEST QPF AMOUNTS WITH THIS STORM ARE GENERALLY NORTH AND EAST
OF THE AREAS THAT HAVE RECEIVED THE HEAVIEST PRECIPITATION OVER
THE PAST COUPLE WEEKS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...WAA
LONG TERM...JNS
AVIATION...JV
HYDROLOGY...WAA/JNS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
237 PM EDT SAT MAY 16 2015
.SYNOPSIS...
WEAK MID/UPPER LEVEL DISTURBANCES...INCREASED MOISTURE AND INSTABILITY
RESULTS IN ROUNDS OF SHOWERS/THUNDERSTORMS INTO EARLY NEXT WEEK. COLD
FRONT PUSHES EAST TUESDAY. DRIER WEDNESDAY.
&&
.NEAR TERM /THROUGH SUNDAY/...
STILL HIGHLIGHTING THE RAIN...OVER ANY CONVECTIVE SEVERE THREAT FOR
LARGE HAIL AND DAMAGING WINDS.
THINKING WE COULD HAVE SOME EFFICIENT RAIN MAKERS/DUMPERS NEXT 24
HOURS...AS PRECIPITABLE WATER INCREASES TOWARD 1.7 INCHES.
PLUS...WE HAVE WEAK MID/UPPER LEVEL DISTURBANCES TRYING TO RIDE UP
AND OVER THE STUBBORN SE 500 MB RIDGE.
OF COURSE...MOST COUNTIES NEED THE RAIN. PLUS...WE HAVE OUR BIG
CONSUMER NOW WORKING HARD...THAT BEING THE FRESH SPRING VEGETATION.
YET...WE DO NOT WANT TOO MUCH OF A GOOD THING. JUST MENTIONED IN THE
HAZARDOUS WEATHER POTENTIAL ABOUT SOME PROGRESSIVE LOCALIZED
DOWNPOURS. WE JUST HAVE TO WATCH FOR ANY REPETITIVE ACTION.
THAT BEING SAID...THE VORT MAX WE DISCUSSED IN THE MORNING UPDATED
AFD...LIFTED THROUGH NORTH CENTRAL WV ON SCHEDULE AROUND 17Z. A FEW
SPOTS GOT A HALF INCH OF RAIN...MOST GOT MUCH LESS. MOST OF THAT
ENERGY AT 1830Z WAS TRANSFERRING EAST OF US...TOWARD SOUTH CENTRAL
PENNSYLVANIA AND FAR EASTERN WV PANHANDLE.
NEXT VORT MAX ON RAP MOVES OUT OF KENTUCKY AND TOWARD MID OHIO
VALLEY AND PKB BY 01Z SUNDAY. SO MENTIONED SOME LOCALIZED DOWNPOURS
ASSOCIATED WITH IT...ACROSS OUR WESTERN COUNTIES.
MOST MODEL SOLUTIONS SHOW ANOTHER 500 MB DISTURBANCE LATE TONIGHT
FROM 06Z TO 12Z SUNDAY...RIDGING THROUGH SE OHIO THEN ACROSS
NORTHERN WV SUNDAY MORNING. SO OF COURSE...HAD TO LEAVE POPS
THROUGH THE NIGHT...HIGHEST IN THE WEST AND NORTH...LOWEST IN THE
SOUTH AND EAST.
NO BIG CHANGES PICTURED FOR SUNDAY...THROUGH THE HIGHER POPS MAY
TRANSFER TO THE MOUNTAINS SUNDAY AFTERNOON...BEFORE TRANSFERRING
BACK WEST AGAIN.
FIGURING MAXIMUM TEMPERATURES REMAIN A HEADACHE...JUST DEPENDING ON
THE BREAKS IN THE CLOUDS AND TIMING OF THE SHOWERS.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS NOTED BY PREVIOUS SHIFT...MODELS HAVE SLOWED DOWN COLD FRONT
PASSAGE UNTIL TUESDAY. MAIN CHANGES THIS FORECAST PACKAGE WERE TO
INCREASE POPS SOME ON TUESDAY AND ALSO TRY TO A THIN LINE OF HIGHER
POPS ALONG THE FRONT AS IT MOVES THROUGH ON TUESDAY. HAVE THE
HIGHEST POPS ACROSS THE EAST...AS THE FRONT WILL BE CROSSING THERE
DURING THE AFTERNOON. WITH THE DELAYED FROPA...ALSO RAISED
TEMPERATURES A BIT MONDAY NIGHT AND TUESDAY. OUTSIDE OF THESE
CHANGES...MAINTAINED LIKELY POPS ON MONDAY IN THE WARM SECTOR.
PRECIPITABLE WATER VALUES ON MONDAY WILL BE AROUND 1.75 INCHES. THIS
WILL LIKELY PRODUCE POCKETS OF HEAVY RAIN IN AREAS OF HEALTHY
CONVECTION. STORMS SHOULD MAINLY BE SCATTERED IN NATURE...WITH
LITTLE SYNOPTIC ORGANIZATIONAL FORCING...SO WILL JUST HAVE TO WATCH
FOR AREAS THAT MAY RECEIVE REPETITIVE BURSTS AS THE DAY GOES ON.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
NO REAL SIGNIFICANT WEATHER MAKERS IN THE LONG TERM PATTERN. THE
PERIOD WILL START OUT ON THE NEAR NORMAL TO COOL SIDE IN THE WAKE OF
TUESDAYS COLD FRONT. GFS/ECMWF BOTH SHOW A SURFACE HIGH SLOWLY
MARCHING ACROSS THE NORTHERN PLAINS FOR THE LATTER HALF OF THE WEEK
INTO THE WEEKEND. ANY PRECIPITATION SHOULD BE TIED TO 500MB RIPPLES
WORKING THROUGH THE FAIRLY ZONAL FLOW. HAVE SOME SLIGHT CHANCE POPS
ACROSS THE HIGHER TERRAIN THURSDAY AND FRIDAY AFTERNOON...BUT
CONFIDENCE ON THIS IS RATHER LOW AT THIS POINT. TEMPERATURES WILL BE
BACK UP TO NEAR AND ABOVE NORMAL BY THE END OF THE WEEK.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
HIGHLY VARIABLE CONDITIONS IN ROUNDS OF SHOWERS AND THUNDERSTORMS.
THINKING THE CONVECTION MOST WIDESPREAD IN THE WESTERN LOWLANDS
INCLUDING SOUTHEAST OHIO AND NORTHEAST KENTUCKY. HAVE ONE LOBE OF
CONVECTION LIFTING NNE THROUGH THOSE COUNTIES 19Z TODAY TO 00Z
SUNDAY.
MORE SHOWERS WITH EMBEDDED THUNDERSTORMS COULD EASILY FORM OVERNIGHT
EVEN 06Z TO 12Z.
OUTSIDE OF THE CONVECTION...HAVE VSBY BECOMING 3 TO 5 MILES IN LIGHT
FOG 06Z TO 12Z. HOPING LAYERED CLOUDS AND BOUNDARY LAYER WINDS KEEP
THREAT FOG OUTSIDE OF THE CONVECTION FROM FORMING.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM
ALTERNATE SCENARIOS: HIGHLY VARIABLE CONDITIONS IN THE SHOWERS AND
STORMS WITH CONDITIONS BRIEFLY GOING LOWER THAN FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H H H M M M M M M
HTS CONSISTENCY H M M M M M M M M M M M
BKW CONSISTENCY H H H H M H M M M M M H
EKN CONSISTENCY H H H H H M M M M M M M
PKB CONSISTENCY H H H H M M M M M M M M
CKB CONSISTENCY M H H H H H M M M M M M
AFTER 18Z SUNDAY...
BRIEF IFR IN SHOWERS AND THUNDERSTORMS POSSIBLE SUNDAY AFTERNOON
INTO TUESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/MZ
NEAR TERM...KTB
SHORT TERM...MZ
LONG TERM...MZ
AVIATION...KTB
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
142 PM EDT SAT MAY 16 2015
.SYNOPSIS...
A SERIES OF WEAK UPPER LEVEL DISTURBANCES WILL AFFECT THE REGION
THIS WEEKEND. A COLD FRONT WILL APPROACH ON MONDAY...MOVING
THROUGH BY EARLY TUESDAY. HIGH PRESSURE BUILDS IN DURING THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PRECIPITATION HAS SLOWLY BEGUN TO INCREASE IN COVERAGE OVER THE
PAST FEW HOURS...AND THIS TREND IS GENERALLY EXPECTED TO CONTINUE
THROUGH EARLY TO MID AFTERNOON. AN ANALYSIS OF LOW-LEVEL WINDS
INDICATES PERSISTENT SOUTHWESTERLY FLOW...BRINGING A CONTINUED
TRANSPORT OF MOISTURE DIRECTLY INTO THE OHIO VALLEY. THERE IS
CONVERGENCE AHEAD OF THIS MOISTURE ADVECTION...AND AS WEAK
INSTABILITY BUILDS...THE COVERAGE AND INTENSITY SHOULD INCREASE AS
WELL. POPS HAVE BEEN REFINED SLIGHTLY BUT REMAIN AT THE HIGH
CHANCE TO LIKELY LEVELS ACROSS THE FORECAST AREA (PRIMARILY AROUND
18Z-21Z). IF THE HRRR VERIFIES...PRECIPITATION MAY END UP EVEN
MORE WIDESPREAD...AND FUTURE UPDATES MAY NEED TO INCREASE THE
PRECIPITATION CHANCES EVEN FURTHER.
THE 12Z KILN SOUNDING IS VERY MOIST (PWAT OF 1.42 INCHES) WITH
POOR LAPSE RATES THROUGH THE ENTIRE DEPTH OF THE TROPOSPHERE.
THIS WILL LIMIT INSTABILITY TODAY...WITH A NARROW PROFILE OF CAPE
THAT MAY GET TO AROUND 1000 J/KG AT MOST. WITH WEAK SHEAR...STORM
ORGANIZATION SHOULD NOT BE MUCH TO SPEAK OF...AND THUS THE THREAT
FOR STRONG STORMS APPEARS LOW.
TEMPERATURES WERE ADJUSTED JUST SLIGHTLY DOWNWARD...WITH
CONFIDENCE IN CLOUDS AND PRECIPITATION (AND A MOIST BOUNDARY
LAYER) LIMITING HEATING POTENTIAL.
PREVIOUS DISCUSSION >
A FEW SHOWERS CONTINUE TO AFFECT WESTERN/CENTRAL OHIO AT 07Z. THIS
ACTIVITY WILL CONTINUE TO MOVE NORTH-NORTHEAST OVER THE NEXT FEW
HOURS...LIKELY DISSIPATING BY SUNRISE.
RIDGE AXIS HAS SHIFTED A LITTLE EAST OF THE OHIO
VALLEY EARLY THIS MORNING...RESULTING IN A BROAD SOUTHWEST FLOW
ALOFT. WEAK VORT MAXES EMBEDDED WITHIN THIS FLOW WILL CONTINUE TO
SUPPORT PERIODS OF CONVECTIVE ACTIVITY THROUGH THE DAY. IT LOOKS
LIKE THE NEXT ROUND OF CONVECTION WILL LIKELY OCCUR IN NORTHERN
KENTUCKY/SOUTHWEST OHIO BY 10-11Z...MOVING NORTHEAST DURING THE
MORNING. THEN AN ADDITIONAL UPTICK IN CONVECTION WILL LIKELY OCCUR
FOR THE MIDDAY/AFTERNOON GIVEN INCREASING PRECIPITABLE WATER
VALUES /POSSIBLY AROUND 1.7 INCHES BY AFTERNOON/...AFTERNOON
INSTABILITY AND THE LIKELIHOOD OF ANOTHER VORT MAX PROMOTING LIFT.
WENT WITH HIGH CHANCE TO LOW END LIKELY POPS ACROSS THE CWA DURING
THIS TIME.
GIVEN RELATIVE WEAK INSTABILITY /MOST GUIDANCE SUGGESTING CAPE
LESS THAN 1000 J/KG/ AND SHEAR...SEVERE WEATHER IS NOT EXPECTED.
HOWEVER CAN/T RULE OUT A LOCALLY STRONG STORM WITH GUSTY WINDS AND
ALSO GIVEN HIGHER MOISTURE CONTENT LOCALLY HEAVY DOWNPOURS MAY
RESULT.
USED A BLEND OF BIAS CORRECTED MET/MAV FOR HIGH TEMPERATURES
TODAY...FAVORING UPPER 70S/AROUND 80 ACROSS MUCH OF THE CWA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
WHILE COVERAGE OF CONVECTION FROM THE AFTERNOON/EARLY EVENING
SHOULD WANE OVERNIGHT...WILL CONTINUE WITH LOW CHANCE POPS ACROSS
THE CWA AS ATMOSPHERE WILL REMAIN WARM/MOIST AND ANY VORT MAX MAY
KEEP SOME CONVECTION GOING INTO THE NIGHT.
SIMILAR SITUATION IS EXPECTED ON SUNDAY...WITH A CHANCE OF SHOWERS
AND THUNDERSTORMS THROUGHOUT THE DAY BUT THE HIGHEST COVERAGE TO
FAVOR THE AFTERNOON. A COLD FRONT IS THEN EXPECTED TO APPROACH ON
MONDAY. WIND FIELDS MAY BE A LITTLE BETTER AND COULD PROMOTE SOME
DEGREE OF ORGANIZATION TO THUNDERSTORMS. CONFIDENCE IS LOW HOWEVER
AND WILL LEAVE MENTION OF STRONG/SEVERE STORMS OUT OF THE HWO
ATTM. MONDAY WILL FEATURE ONE MORE WARM/MUGGY DAY BEFORE CHANGES
OCCUR BEHIND THE FRONT.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A COLD FRONT WILL THEN MOVE THROUGH THE AREA LATE MONDAY NIGHT AND
TUESDAY MORNING WITH DRIER AND COOLER AIR MOVING IN BEHIND.
MODELS HAVE SLOWED THE FRONT DOWN A BIT AND GIVEN CURRENT
FORECASTED UPPER LEVEL FLOW THIS MAKES SENSE. THE UPPER LEVEL LOW
JUST NORTH OF WISCONSIN MONDAY WASHES OUT WITH A SECONDARY
SHORTWAVE MOVING SOUTH TUESDAY INTO WEDNESDAY. FORECASTED 850
TEMPERATURES FOR NEXT WEEK (5 - 10 DEGREES C) ALSO DON`T LOOK AS
COOL AS THEY WERE OVER THE LAST COUPLE OF DAYS. HAVE TRENDED HIGH
TEMPERATURES UP TOWARDS 70 A BIT TO ACCOUNT FOR THIS. BELOW NORMAL
TEMPERATURES WILL THEN CONTINUE THROUGH THE END OF THE NEXT WORK
WEEK.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
ALTHOUGH SCATTERED SHOWERS HAVE BEEN AROUND THE TAF SITES ALL
MORNING...A MORE STEADY AREA OF RAIN (WITH EMBEDDED CONVECTION) IS
NOW MOVING INTO THE CINCINNATI AIRPORTS...AND WILL SPREAD NORTH TO
DAYTON AND COLUMBUS IN THE NEXT COUPLE HOURS. PREVAILING MVFR
CONDITIONS ARE EXPECTED...THOUGH A HEAVY DOWNPOUR COULD BRING
BRIEF IFR CONDITIONS. THUNDER REMAINS A POSSIBILITY...BUT FOR THE
MOST PART THERE HAS NOT BEEN AN ABUNDANCE OF LIGHTNING OBSERVED IN
THE CURRENT PRECIPITATION...SO THIS HAS NOT BEEN INCLUDED
SPECIFICALLY IN THE TAFS.
RAIN IS EXPECTED TO BECOME MORE SCATTERED THIS EVENING AND INTO
THE OVERNIGHT. HOWEVER...MVFR CEILINGS ARE EXPECTED TO REMAIN IN
PLACE.
THERE IS THE POTENTIAL FOR ADDITIONAL SHOWER AND THUNDERSTORM
DEVELOPMENT LATE IN THE TAF PERIOD...BOTH EARLY SUNDAY MORNING AS
WELL AS SUNDAY AFTERNOON. THE EXACT TIMING AND INTENSITY OF THIS
POTENTIAL DEVELOPMENT IS UNCERTAIN...SO A VCSH WILL BE USED
THROUGHOUT THE REST OF THE TAF PERIOD.
WINDS THROUGH THE TAF PERIOD WILL BE OUT OF THE SSW...GENERALLY AT
AROUND 10 KNOTS.
OUTLOOK...THUNDERSTORMS WILL BE POSSIBLE AT TIMES ON SUNDAY AND
MONDAY. MVFR CEILINGS MAY ALSO OCCUR AT TIMES ON SUNDAY AND MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BPP
NEAR TERM...HATZOS/BPP
SHORT TERM...BPP
LONG TERM...HAINES
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1000 AM EDT SAT MAY 16 2015
.SYNOPSIS...
A SERIES OF WEAK UPPER LEVEL DISTURBANCES WILL AFFECT THE REGION
THIS WEEKEND. A COLD FRONT WILL APPROACH ON MONDAY...MOVING
THROUGH BY EARLY TUESDAY. HIGH PRESSURE BUILDS IN DURING THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PRECIPITATION HAS SLOWLY BEGUN TO INCREASE IN COVERAGE OVER THE
PAST FEW HOURS...AND THIS TREND IS GENERALLY EXPECTED TO CONTINUE
THROUGH EARLY TO MID AFTERNOON. AN ANALYSIS OF LOW-LEVEL WINDS
INDICATES PERSISTENT SOUTHWESTERLY FLOW...BRINGING A CONTINUED
TRANSPORT OF MOISTURE DIRECTLY INTO THE OHIO VALLEY. THERE IS
CONVERGENCE AHEAD OF THIS MOISTURE ADVECTION...AND AS WEAK
INSTABILITY BUILDS...THE COVERAGE AND INTENSITY SHOULD INCREASE AS
WELL. POPS HAVE BEEN REFINED SLIGHTLY BUT REMAIN AT THE HIGH
CHANCE TO LIKELY LEVELS ACROSS THE FORECAST AREA (PRIMARILY AROUND
18Z-21Z). IF THE HRRR VERIFIES...PRECIPITATION MAY END UP EVEN
MORE WIDESPREAD...AND FUTURE UPDATES MAY NEED TO INCREASE THE
PRECIPITATION CHANCES EVEN FURTHER.
THE 12Z KILN SOUNDING IS VERY MOIST (PWAT OF 1.42 INCHES) WITH
POOR LAPSE RATES THROUGH THE ENTIRE DEPTH OF THE TROPOSPHERE.
THIS WILL LIMIT INSTABILITY TODAY...WITH A NARROW PROFILE OF CAPE
THAT MAY GET TO AROUND 1000 J/KG AT MOST. WITH WEAK SHEAR...STORM
ORGANIZATION SHOULD NOT BE MUCH TO SPEAK OF...AND THUS THE THREAT
FOR STRONG STORMS APPEARS LOW.
TEMPERATURES WERE ADJUSTED JUST SLIGHTLY DOWNWARD...WITH
CONFIDENCE IN CLOUDS AND PRECIPITATION (AND A MOIST BOUNDARY
LAYER) LIMITING HEATING POTENTIAL.
PREVIOUS DISCUSSION >
A FEW SHOWERS CONTINUE TO AFFECT WESTERN/CENTRAL OHIO AT 07Z. THIS
ACTIVITY WILL CONTINUE TO MOVE NORTH-NORTHEAST OVER THE NEXT FEW
HOURS...LIKELY DISSIPATING BY SUNRISE.
RIDGE AXIS HAS SHIFTED A LITTLE EAST OF THE OHIO
VALLEY EARLY THIS MORNING...RESULTING IN A BROAD SOUTHWEST FLOW
ALOFT. WEAK VORT MAXES EMBEDDED WITHIN THIS FLOW WILL CONTINUE TO
SUPPORT PERIODS OF CONVECTIVE ACTIVITY THROUGH THE DAY. IT LOOKS
LIKE THE NEXT ROUND OF CONVECTION WILL LIKELY OCCUR IN NORTHERN
KENTUCKY/SOUTHWEST OHIO BY 10-11Z...MOVING NORTHEAST DURING THE
MORNING. THEN AN ADDITIONAL UPTICK IN CONVECTION WILL LIKELY OCCUR
FOR THE MIDDAY/AFTERNOON GIVEN INCREASING PRECIPITABLE WATER
VALUES /POSSIBLY AROUND 1.7 INCHES BY AFTERNOON/...AFTERNOON
INSTABILITY AND THE LIKELIHOOD OF ANOTHER VORT MAX PROMOTING LIFT.
WENT WITH HIGH CHANCE TO LOW END LIKELY POPS ACROSS THE CWA DURING
THIS TIME.
GIVEN RELATIVE WEAK INSTABILITY /MOST GUIDANCE SUGGESTING CAPE
LESS THAN 1000 J/KG/ AND SHEAR...SEVERE WEATHER IS NOT EXPECTED.
HOWEVER CAN/T RULE OUT A LOCALLY STRONG STORM WITH GUSTY WINDS AND
ALSO GIVEN HIGHER MOISTURE CONTENT LOCALLY HEAVY DOWNPOURS MAY
RESULT.
USED A BLEND OF BIAS CORRECTED MET/MAV FOR HIGH TEMPERATURES
TODAY...FAVORING UPPER 70S/AROUND 80 ACROSS MUCH OF THE CWA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
WHILE COVERAGE OF CONVECTION FROM THE AFTERNOON/EARLY EVENING
SHOULD WANE OVERNIGHT...WILL CONTINUE WITH LOW CHANCE POPS ACROSS
THE CWA AS ATMOSPHERE WILL REMAIN WARM/MOIST AND ANY VORT MAX MAY
KEEP SOME CONVECTION GOING INTO THE NIGHT.
SIMILAR SITUATION IS EXPECTED ON SUNDAY...WITH A CHANCE OF SHOWERS
AND THUNDERSTORMS THROUGHOUT THE DAY BUT THE HIGHEST COVERAGE TO
FAVOR THE AFTERNOON. A COLD FRONT IS THEN EXPECTED TO APPROACH ON
MONDAY. WIND FIELDS MAY BE A LITTLE BETTER AND COULD PROMOTE SOME
DEGREE OF ORGANIZATION TO THUNDERSTORMS. CONFIDENCE IS LOW HOWEVER
AND WILL LEAVE MENTION OF STRONG/SEVERE STORMS OUT OF THE HWO
ATTM. MONDAY WILL FEATURE ONE MORE WARM/MUGGY DAY BEFORE CHANGES
OCCUR BEHIND THE FRONT.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A COLD FRONT WILL THEN MOVE THROUGH THE AREA LATE MONDAY NIGHT AND
TUESDAY MORNING WITH DRIER AND COOLER AIR MOVING IN BEHIND.
MODELS HAVE SLOWED THE FRONT DOWN A BIT AND GIVEN CURRENT
FORECASTED UPPER LEVEL FLOW THIS MAKES SENSE. THE UPPER LEVEL LOW
JUST NORTH OF WISCONSIN MONDAY WASHES OUT WITH A SECONDARY
SHORTWAVE MOVING SOUTH TUESDAY INTO WEDNESDAY. FORECASTED 850
TEMPERATURES FOR NEXT WEEK (5 - 10 DEGREES C) ALSO DON`T LOOK AS
COOL AS THEY WERE OVER THE LAST COUPLE OF DAYS. HAVE TRENDED HIGH
TEMPERATURES UP TOWARDS 70 A BIT TO ACCOUNT FOR THIS. BELOW NORMAL
TEMPERATURES WILL THEN CONTINUE THROUGH THE END OF THE NEXT WORK
WEEK.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
UNSETTLED WEATHER OVER THE OHIO VALLEY WILL NECESSITATE SOME TYPE
OF SHOWER AND THUNDERSTORM MENTION AT ALL TAF SITES FOR THE
FORESEEABLE FUTURE. SOUTHERLY FLOW WILL CONTINUE TO PUMP INCREASED
MOISTURE TO THE REGION AND MID LEVEL SHORTWAVES WILL TRAVERSE A H5
RIDGE THAT IS IN PLACE OVER THE EASTERN U.S. THIS ESTABLISHED RIDGE
WILL KEEP MOST STORMS IN CHECK AND THE CONSENSUS IN THE NEXT DAY
OR TWO IS FOR GARDEN VARIETY THUNDERSTORMS OF A SCATTERED NATURE
BECOMING MORE NUMEROUS DURING THE DAY.
SHOWERS AND OCCASIONAL THUNDERSTORMS WILL DROP VSBYS TO MVFR
VALUES BUT MOST CIGS SHOULD REMAIN VFR FOR THE NEXT 24-30 HOURS.
SATURATED CONDITIONS THROUGH THE LOWER ATMOSPHERE WILL BE FOUND AT
VARIOUS LEVELS THAT WILL BE AS DIFFICULT TO PINPOINT AS THE
LOCATIONS OF THE STORMS. CONTINUE TO LEAVE OUT MVFR CIGS FROM
CU/SC WHILE DROPPING THEM SLIGHTLY IN PRECIP WHICH IS MORE HEAVILY
FOCUSED IN TEMPO GROUPS.
WINDS WILL BE SSW AT 10KT OR LESS.
OUTLOOK...THUNDERSTORMS POSSIBLE SUNDAY THROUGH MONDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...BPP
NEAR TERM...HATZOS/BPP
SHORT TERM...BPP
LONG TERM...HAINES
AVIATION...FRANKS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
941 AM EDT SAT MAY 16 2015
.SYNOPSIS...
WEAK MID/UPPER LEVEL DISTURBANCES...INCREASED MOISTURE AND INSTABILITY
RESULTS IN ROUNDS OF SHOWERS/THUNDERSTORMS INTO EARLY NEXT WEEK. COLD
FRONT PUSHES EAST TUESDAY. DRIER WEDNESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
FROM 00Z TO 12Z SOUNDINGS...SHOW PRECIPITABLE WATER AT BNA INCREASED
FROM 1.3 TO 1.7 INCHES...AT ILN FROM 1.1 TO 1.4 INCHES. PIT DID NOT
INCREASE MUCH IN PAST 12 HRS.
VERY WEAK 500 MB VORT MAX ON RAP LIFTS FROM HTS VCNTY AT 13Z THROUGH
NORTH CENTRAL WV 17-19Z...BUT OVERALL 500 HEIGHTS ARE NOT FALLING.
AS A RESULT...INCREASED POPS A BIT QUICKER IN WESTERN WEST VIRGINIA
THIS MORNING INTO EARLY AFTERNOON.
ANOTHER 500 MB DISTURBANCE MAY LIFT OUT OF TENNESSEE RIVER VALLEY
TODAY...REACHING US TONIGHT. WE MAINTAIN AT LEAST CHANCE POPS
THROUGH THE NIGHT. WITH PLENTY OF LAYERED CLOUDS OVERNIGHT...DID NOT
HIT FOG HARD OVERNIGHT FOR THE PUBLIC...BUT COULD EASILY BE 3 TO 5
MILES.
DID LOWER MAX TEMP A FEW DEGREES IN SOUTHEAST OHIO AND NRN WV
TODAY...FIGURING ON THE AFFECTS OF THIS FIRST DISTURBANCE.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
MODELS SHOW H500 RIDGE AXIS MOVING OVER WV SUNDAY. THE CMC/NAM/GFS
MODELS SHOW FEW VORTICITY MAX ALONG THIS RIDGE FLOW FROM 12Z SUNDAY
THROUGH 00Z MONDAY. MODELS ALSO SHOW AN INCREASE IN PRECIPITABLE
WATER REACHING 1.9 INCHES BY 18Z SUNDAY. H850 FLOW BECOMES STEADY
FROM THE SOUTHWEST PUMPING JUICIER AND WARMER AIR MASS TO THE
AREA. THUS...UNSETTLED ATMOSPHERE...WITH SFC CAPE FROM 1800-2000
J/KG SUGGEST GOOD CHANCE FOR SHOWERS AND THUNDERSTORMS MAINLY DURING
THE AFTERNOON HOURS.
BY MONDAY...A COLD FRONT CROSSES THE OH VALLEY...KEEPING OUR AREA
UNDER A WARM SECTOR. WITH BETTER SUPPORT FROM THIS COLD
FRONT...SUSPECT CONVECTION AHEAD OF THE FRONT WILL LIGHT UP TO
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS. PRECIPITABLE WATER
AROUND 1.7 AHEAD OF THE FRONT SUGGEST SOME STORMS COULD PRODUCE
HEAVY DOWNPOURS MONDAY. KEPT LIKELY POPS WITH THIS ENVIRONMENT. THE
COLD FRONT SHOULD REACH SOUTHEAST OH BY 12Z TUESDAY...CROSSING EAST
ENDING PCPN BY 00Z WEDNESDAY.
EXPECT ABOVE NORMAL TEMPERATURES SUNDAY AND MONDAY BECOMING NEAR
NORMAL TUESDAY. USED A BLEND OF PREVIOUS NUMBERS AND THE BIAS
CORRECTED CONSENSUS ALL GUIDANCE FOR TEMPERATURES THROUGH THE
PERIOD.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
A COLD FRONT WILL PUSH THROUGH MONDAY NIGHT. ECMWF HAS PERSISTENTLY
BEEN PUSHING IT THROUGH CLEANLY...WHILE THE GFS HAS AT TIMES SHOWED
SIGNS OF IT GETTING HUNG UP...BUT RECENTLY HAS BEEN SHOWING THE
CLEAN SWEET AS WELL. SO MINIMAL CHANGES TO PREVIOUS FORECAST...WITH
DRIER AND COOLER AIR FILTERING IN MID WEEK. THINGS MAY GET A LITTLE
MESSIER AT THE END OF THE WEEK AND INTO THE WEEKEND AS MOISTURE
BEGINS TO RETURN.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
06Z SATURDAY THRU 06Z SUNDAY...
ISOLATED STORMS HAVE PUSHED EAST OF THE AREA AT THIS TIME. VFR
CONDITIONS PREVAILED IN MOST LOCATIONS...WITH SOME VALLEY
LOCATIONS SEEING MVFR AND EVEN IFR VSBYS.
ADDITIONAL SHOWERS AND STORMS...WHICH WERE APPROACHING FROM THE
WEST...SHOULD SPREAD EAST ACROSS THE REGION...AND INCREASE IN
AREAL COVERAGE. CURRENT THINKING IS THE GREATEST CONCENTRATION OF
STORMS SHOULD OCCUR BETWEEN 17Z AND 23Z. EXPECT BRIEF MVFR AND
IFR CONDITIONS IN VICINITY OF STORMS. GUSTY WINDS ARE ALSO
POSSIBLE WITH THE STRONGER STORMS.
THE STORMS SHOULD BEGIN TO DECREASE IN INTENSITY AND AREAL COVERAGE
AFTER 03Z. WHILE CONDITIONS SHOULD BE VFR IN MOST LOCATIONS...MVFR
AND IFR CONDITIONS WILL BE POSSIBLE ALONG RIVER VALLEYS AND IN
AREAS THAT RECEIVED RAINFALL TODAY.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z SUNDAY...
FORECAST CONFIDENCE: MEDIUM
ALTERNATE SCENARIOS: STORMS WITH ISOLATED CONDITIONS MAY NOT BE AS
NUMEROUS AS EXPECTED.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY M H M H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H M H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z SUNDAY...
BRIEF IFR IN THUNDERSTORMS POSSIBLE THROUGH TUESDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/KTB/ARJ
NEAR TERM...KTB
SHORT TERM...ARJ
LONG TERM...MZ
AVIATION...JSH
AREA FORECAST DISCUSSION
NWS TULSA OK
935 PM CDT SUN MAY 17 2015
.DISCUSSION...
A MUCH QUIETER EVENING AS THE AREA HAS REMAINED PRECIP FREE FOR
THE DURATION. BOUNDARY SEPARATING DEW POINTS IN UPPER 60S TO NEAR
70S FROM DRIER AIR EXTENDS FROM SOUTH CENTRAL OK INTO WESTERN
OSAGE COUNTY AND NEAR THIS INTERFACE WITH LIGHT WINDS SOME FOG
DEVELOPMENT REMAINS POSSIBLE. WARM MOIST SECTOR OVER WESTERN OK
AND WESTERN AR REMAINS CAPPED AND SHORT RANGE GUIDANCE INCLUDING
THE 00Z NAM TRENDING TOWARD A DRIER SOLUTION FOR TONIGHT. WILL
KEEP SLIGHT CHANCE ACROSS FAR EASTERN/SOUTHERN AREAS AS A SUBTLE
WAVER MOVES ACROSS TONIGHT AND MAY HAVE JUST ENOUGH LIFT TO SPARK
A FEW SHOWERS LATE TONIGHT OR EARLY MON MORNING. UPDATED PRODUCTS
WILL BE OUT SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 634 PM CDT SUN MAY 17 2015/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
SCATTERED TO BROKEN MID/HIGH CLOUDS WILL CONTINUE OVERNIGHT AS
WEAK UPPER DISTURBANCE TRAVERSES THE AREA. COULD SEE SOME
LIGHT FOG TOWARDS MORNING AS WINDS BECOME LIGHT AHEAD OF APPROACHING
FRONTAL BOUNDARY. OTHERWISE...VFR CONDITIONS EXPECTED THROUGH
THE FORECAST PERIOD.
PREV DISCUSSION... /ISSUED 359 PM CDT SUN MAY 17 2015/
DISCUSSION...
NEXT COUPLE OF DAYS MARGINAL CHANCE FOR SHOWERS
THUNDERSTORMS MAINLY SOUTH WHERE BETTER MOISTURE
RESIDES. WRF MODEL AN OUTLIER REGARDING PRECIP
AND POP SOUTHEAST AND NORTHWEST ARKANSAS. DRIER
SHORT TERM HRRR LOOKS GOOD TONIGHT.
NEXT BIG RAIN TUESDAY NIGHT WEDNESDAY WHEN THE
NEXT SHOT OF ENERGY EJECTED FROM THE SOUTHWEST.
CHANCE POPS THURSDAY INTO FRIDAY.
UPPER LOW OVER THE SOUTHWEST FRIDAY MOVES ACROSS
THE ROCKIES AND INTO THE CENTRAL PLAINS...SUNDAY.
ANOTHER SLUG WET WEATHER FOR THE HOLIDAY WEEKEND.
GW
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 64 83 60 75 / 10 10 10 10
FSM 68 84 66 81 / 20 30 20 20
MLC 67 84 63 80 / 10 20 20 30
BVO 58 81 54 72 / 10 10 10 10
FYV 62 81 58 76 / 20 30 20 10
BYV 64 81 57 75 / 20 30 20 10
MKO 64 83 61 77 / 10 10 10 30
MIO 63 80 56 73 / 10 10 10 10
F10 64 83 61 77 / 10 10 10 30
HHW 68 83 67 81 / 30 30 20 40
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...14
LONG TERM....99
AREA FORECAST DISCUSSION
NWS TULSA OK
634 PM CDT SUN MAY 17 2015
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
SCATTERED TO BROKEN MID/HIGH CLOUDS WILL CONTINUE OVERNIGHT AS
WEAK UPPER DISTURBANCE TRAVERSES THE AREA. COULD SEE SOME
LIGHT FOG TOWARDS MORNING AS WINDS BECOME LIGHT AHEAD OF APPROACHING
FRONTAL BOUNDARY. OTHERWISE...VFR CONDITIONS EXPECTED THROUGH
THE FORECAST PERIOD.
&&
.PREV DISCUSSION... /ISSUED 359 PM CDT SUN MAY 17 2015/
DISCUSSION...
NEXT COUPLE OF DAYS MARGINAL CHANCE FOR SHOWERS
THUNDERSTORMS MAINLY SOUTH WHERE BETTER MOISTURE
RESIDES. WRF MODEL AN OUTLIER REGARDING PRECIP
AND POP SOUTHEAST AND NORTHWEST ARKANSAS. DRIER
SHORT TERM HRRR LOOKS GOOD TONIGHT.
NEXT BIG RAIN TUESDAY NIGHT WEDNESDAY WHEN THE
NEXT SHOT OF ENERGY EJECTED FROM THE SOUTHWEST.
CHANCE POPS THURSDAY INTO FRIDAY.
UPPER LOW OVER THE SOUTHWEST FRIDAY MOVES ACROSS
THE ROCKIES AND INTO THE CENTRAL PLAINS...SUNDAY.
ANOTHER SLUG WET WEATHER FOR THE HOLIDAY WEEKEND.
GW
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...12
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1202 PM EDT SAT MAY 16 2015
.SYNOPSIS...
A STALLED FRONTAL ZONE WILL BE THE FOCUS FOR PERIODS OF UNSETTLED
WEATHER THIS WEEKEND...AS SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED EACH DAY. THE WEEKEND WILL NOT BE A WASHOUT...AS THERE
WILL BE DRY TIMES WITH PERIODS OF SUNSHINE AS WELL. A RELATIVELY
STRONG COLD FRONT WILL PUSH ACROSS THE AREA MONDAY NIGHT AND
TUESDAY...USHERING IN ANOTHER COOL...DRY AIRMASS FOR LATE TUESDAY
THROUGH THURSDAY.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
1150 AM UPDATE...
CONVECTIONWANED FOR A BIT...BUT STARTING UP AGAIN. HRRR HAS A
GREAT HANDLE ON CURRENT CROP OF STORMS...INCL THE STUFF NEAR
KHLG/KPIT AND KBFD. HEATING WILL POP CONVECTION IN MANY MORE
LOCATIONS AS THE SHORT WAVE DRIVING THE CURRENT ACTIVITY RUNS INTO
THE CURRENTLY SUNNY AREA. WILL KNOCK TEMPS DOWN A BIT IN THE NW
AND UP SLIGHTLY FOR THE NEXT FEW HRS IN THE SE. THEN WIDESPREAD
CONVECTION SHOULD COOL IT OFF. SEVERE THREAT STILL LURKING AROUND
THE CORNER...WITH BEST GUIDANCE ALSO INDICATING SOME STRONGER WINDS
ALOFT. WOULD NOT BE SURPRISED TO SEE A BOX SOMETIME THIS
AFTN...ESP IF THE CLUSTER OVER KPIT CONTINUES TO INCREASE IN
COVG/INTENSITY...WHICH SEEMS MORE THAN LIKELY.
PREV...
SCATTERED SHOWERS CONTINUE TO TRACK ACROSS THE NORTHERN HALF OF
CENTRAL PA...NOW ACCOMPANIED BY ISOLATED THUNDER AS STATIC
STABILITY HAS DECREASED OVERNIGHT WITH THE PASSING OF A SHORTWAVE
TROF FROM THE EASTERN GLAKS CROSSING THE FINGERLAKES REGION.
MARGINALLY UNSTABLE AIR MASS WITH MODERATE MOISTURE (PW ~1.5") AND
BOUNDARY LAYER CONVERGENCE INVOF STALLED WARM FRONT WILL FOCUS
SHOWER AND THUNDERSTORM CHANCES THROUGHOUT THE DAY. SHOWERS WILL
BE MOST PROBABLE AND NUMEROUS ACROSS THE NORTHERN HALF OF CENTRAL
PA...BUT EVEN THE SOUTH CAN SEE AN ISOLATED SHOWER OR THUNDERSTORM
AT JUST ABOUT ANY TIME...BUT MOST LIKELY DURING MAX DIURNAL
HEATING THIS AFTERNOON. N CENTRAL PA IS IN MARGINAL SPC OUTLOOK
FOR THIS AFTERNOON...SO WILL BE WATCHFUL FOR PULSE STORMS WHICH
COULD PRODUCE HEAVY DOWNPOURS...GUSTY WINDS AND SMALL HAIL.
HIGHS WILL RANGE FROM THE MID 70S NORTH WHERE CLOUDS WILL BE
THICKEST AND SHOWERS AT THEIR MOST FREQUENT...TO THE LOWER TO
MIDDLE 80S SOUTHEAST.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH 6 PM SUNDAY/...
AFOREMENTIONED QUASISTATIONARY BOUNDARY WILL BE DRAPED ACROSS PA
TONIGHT INTO EARLY SUNDAY BEFORE SETTLING SOUTHWARD SUNDAY
AFTERNOON AS DRIER AND COOLER AIR WORKS SOUTHWARD FROM HIGH
PRESSURE OVER NORTHERN NEW ENGLAND AND NEWFOUNDLAND.
WHILE THE TREND WILL BE FOR DECREASING SHOWER ACTIVITY...A SHOWER
OR TSTM CAN/T BE RULED OUT AT PRACTICALLY ANY TIME DURING THIS
PERIOD. KEPT POPS IN THE LOWER TO MID CHC RANGE FROM TONIGHT
THROUGH SUNDAY MORNING...WITH DECREASING POPS SUNDAY AFTERNOON.
LOWS TONIGHT WILL RANGE FROM THE UPPER 50S NORTH TO THE MID 60S
SOUTHEAST. HIGHS WILL ONCE AGAIN RANGE FROM THE MID 70S NORTH TO
AROUND 80 OVER THE LOWER SUSQ.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
LEAD SHORTWAVE ENERGY CLIMBING THE WESTERN-SIDE OF ANOMALOUS
500MB RIDGE OVER THE EASTERN US...ALONG WITH ABOVE NORMAL PWATS
AND DIURNAL INSTABILITY WILL HELP PROMOTE SCATTERED CONVECTION ON
SUNDAY...ESPECIALLY ALONG/SOUTH OF THE QUASI-STNRY/WARM FRONTAL
BOUNDARY PIVOTING OVER THE AREA. USED A BLEND FOR POPS/QPF WHICH
FAVORED THE LAUREL HIGHLANDS AND SOUTH-CENTRAL MTNS ON DAY 3.
GIVEN LACK OF FORCING AND LOSS OF DAYTIME HEATING...CUT BACK POPS
TO THE MID-CHC RANGE SUNDAY NIGHT /40 PERCENT WEST TO 30 PERCENT
EAST/.
THE VIGOROUS/DEEP CLOSED LOW EJECTING OUT OF THE SOUTHWESTERN
U.S. SHOULD REACH THE NORTHERN PLAINS BY 00Z MON...WHERE THE
MODELS SHOW IT SLOWING DOWN AND EVENTUALLY BECOMING ABSORBED INTO
AN UPPER TROUGH CROSSING HUDSON BAY. THIS HAS APPEARED TO SLOW
THE EASTWARD PROGRESSION OF ITS TRAILING COLD FRONT BY 12HRS OR
SO...NOW PROGGED TO CROSS THE AREA DURING THE DAYTIME ON TUESDAY
(PREVIOUSLY MONDAY NIGHT/AM TUESDAY). THIS SLOWER TREND WAS EVIDENT
IN THE GUIDANCE AND HAVE ADJUSTED TEMPS AND POPS ACCORDINGLY. THE
PARENT SHORTWAVE WILL LOSE MUCH OF ITS AMPLITUDE AS IT TRACKS
THROUGH THE UPPER GREAT LAKES AND FOR NOW DOES NOT APPEAR TO POSE
A SIGNIFICANT SVR WX RISK FOR EARLY NEXT WEEK.
IN THE WAKE OF THE COLD FRONTAL PASSAGE...A RESPECTABLE ANTICYCLONE
WILL EXTEND SEWD FROM THE UPPER MIDWEST WITH COOLER AND NOTICEABLY
DRIER AIR FILTERING INTO THE REGION FOR THE MID TO LATE WEEK
PERIOD. THIS PATTERN SHOULD SUPPRESS THE PCPN RISK TO THE SOUTH OF
CENTRAL PA WITH GENERALLY FAIR WEATHER AND SEASONABLY COOL TO
MODERATING TEMPERATURES PREVAILING AT DAYS 6-8. ALSO OF NOTE IS
THE RISK FOR PATCHY FROST ON MAY 21ST/THURSDAY MORNING MAINLY OVER
THE NORTH-CENTRAL ZONES WHERE ECENS/GFS ENSEMBLE MOS GUIDANCE IS
SHOWING MID 30S AT BFD...JUST IN TIME FOR THE START OF THE GROWING
SEASON.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
NOON...
CONVECTION MOVING BACK IN FROM THE WEST. WILL ATTEMPT TO TIME IT
INTO JST/AOO/IPT. WINDS MAY BE ERRATIC/GUSTY IN
THUNDERSTORMS...BUT TOO TIGHT OF A WINDOW TO TRY TO MAKE MORE THAN
A TEMPO MENTION OF THAT.
PREV...
THE LAST REMAINING CLUSTER OF SHOWERS AND THUNDERSTORMS HAVE MOVED
PAST IPT AND ARE CONTINUING TO PROGRESS EASTWARD. EXPECT A LULL IN
THE PRECIPITATION THROUGH THE MORNING. HOWEVER AS THE WARM FRONT
LAGS...AND THE TEMPERATURES RISE...PRECIPITATION WILL BEGIN TO
BUBBLE AND MOVE THROUGH CENTRAL PA...AFFECTING MOST TAF SITES AT
TIMES THIS AFTERNOON AND EARLY EVENING. HOWEVER VFR CIGS AND VSBYS
WILL BE DOMINATE WITH MVFR TO IFR IN HEAVIER SHOWERS AND
THUNDERSTORMS. THE STRONGEST STORMS SHOULD BE ALONG THE SOUTHERN
CORRIDOR OF PENNSYLVANIA...AFFECTING JST...AOO...MDT AND LNS.
SHOWERS COULD CONTINUE OVERNIGHT...WITH MVFR CIGS POSSIBLE AFTER
03Z. BFD COULD SEE IFR BY THIS TIME DUE TO CALMING WINDS AND
COPIOUS AMOUNTS OF LOW LEVEL MOISTURE PRESENT. THIS ALSO REMAINS
POSSIBLE AT UNV. WINDS SHOULD PERSIST AT JST WHICH SHOULD ONLY
ALLOW MVFR...THOUGH IFR REMAINS POSSIBLE...THOUGH LOWER
PROBABILITY.
OUTLOOK...
SUN-TUE MORNING...MAINLY VFR...SCT AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS WITH LOCAL REDUCTIONS TO MVFR AND BRIEF IFR
POSSIBLE.
WED-THU...MAINLY VFR WITHIN A COOLER/DRIER AIRMASS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DANGELO/DEVOIR
SHORT TERM...DEVOIR/LAMBERT
LONG TERM...STEINBUGL
AVIATION...DANGELO/CERU
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
653 AM EDT SAT MAY 16 2015
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL REMAIN OVER THE REGION THROUGH THE
WEEKEND. INCREASING MOISTURE OVER THE WESTERN EDGE OF THE HIGH WILL
BRING PRECIPITATION CHANCES MAINLY TO THE MOUNTAINS TODAY AND
SUNDAY. A COLD FRONT APPROACHES MONDAY...POSING BETTER CHANCES FOR
PRECIPITATION FOR THE WHOLE AREA THROUGH TUESDAY. SLIGHTLY COOLER
AND DRIER HIGH PRESSURE WILL RETURN WEDNESDAY IN THE WAKE OF THE
FRONT.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 655 AM EDT...THE EARLY MORNING HOURS HAVE TRENDED LESS CLOUDY
OVER THE HEART OF THE FORECAST AREA...WHICH HAS PERMITTED SOME
PATCHY DENSE FOG TO FORM OVER THE NC FOOTHILLS...MAINLY NEAR
MORGANTON. A LOWER CLOUD DECK DID MANAGE TO DEVELOP ALONG INTERSTATE
77...BUT THIS SHOULD BE MUCH SHORTER LIVED THAN THE LOW CLOUDS
OBSERVED YESTERDAY MORNING GIVEN THE SMALLER SPATIAL EXTENT OF THE
CLOUDS AND EXPECTED MORNING HEATING.
OTHERWISE...A BROAD UPPER LEVEL RIDGE AXIS WILL REMAIN IN PLACE OVER
THE EASTERN THIRD OF THE NATION TODAY THROUGH TONIGHT. THE BEST LOW
TO MID LEVEL MOISTURE RETURN AROUND THE RIDGE WILL CONTINUE TO
AFFECT THE SPINE OF THE SRN APPALACHIANS THROUGH THE PERIOD. WITH
LOW LEVEL WINDS VEERED MORE S TO SW TODAY...TRIGGERING OF SHRA AND
LATER DAY TSRA MAY BE EVEN MORE CONFINED TO THE MTNS...ESPECIALLY
NEAR THE TN BORDER...THAN OBSERVED ON FRI. THERE WILL BE MUCH LESS
IN THE WAY OF EARLY DAY LOW CLOUDS...BUT STILL EXPECT OCNL MID AND
HIGH LEVEL CLOUDS TOPPING THE ERN RIDGE...ALONG WITH A DEVELOPING
CUMULUS FIELD FROM THE RECOVERING SFC DEWPOINTS AND HEATING. ALL
TOLD...ENOUGH INSOLATION IS EXPECTED TO PERMIT TEMPS TO WARM INTO
THE UPPER 70S TO NEAR 80 IN THE LOWER MTN VALLEYS AND 80 TO 85 EAST
OF THE MTNS. SBCAPE VALUES ALONG THE SPINE OF THE MTNS MAY REACH
1000 TO 1500 J/KG...WITH LESSER INSTABILITY EAST DUE TO MORE
NEGATIVE BUOYANCY AREAS IN THE MODEL PROFILES AND BETTER MID LEVEL
CAPPING. STEERING FLOW WILL ONCE AGAIN BE LIGHT...WITH LIGHTNING AND
LOCALLY HEAVY RAINFALL IN THE MTNS THE PRIMARY THREATS WITH ANY
THUNDERSTORMS.
LINGERING EVENING ISOLD TO SCT SHRA/TSRA IN THE MTNS WILL DIMINISH
QUICKLY TONIGHT AND LIKELY DISSIPATE EVERYWHERE BUT THE FAR SW MTNS
OVERNIGHT. MIN TEMPS SHOULD GAIN ANOTHER DEGREE OR SO AS THE AIRMASS
CONTINUES TO MODIFY UNDER SRLY FLOW. IF THE HIGH CLOUDS THIN
SUFFICIENTLY...MTN VALLEY FOG WILL BECOME MORE LIKELY LATE TONIGHT.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 230 AM SAT...SHARP UPPER RIDGE WILL BE SITUATED OVER THE ERN
SEABOARD SUNDAY AS A WELL DEVELOPED LOW PRESSURE SYSTEM MOVES INTO
THE UPPER MISSISSIPPI VALLEY. SW FLOW OFF THE GULF WILL CONTINUE THRU
SUN AFTN...AND CONVECTION IS EXPECTED TO INITIATE OVER THE MTNS IN
TYPICAL FASHION. HOWEVER FAVORABLE PROFILES ARE SEEN ON NAM PROGS
INTO THE FOOTHILLS AS WELL. THE RIDGE PUSHES EWD IN ADVANCE OF THE
LOW SUNDAY NIGHT...ALLOWING SLIGHTLY LOWER HEIGHTS ALOFT MONDAY. THIS
WILL MAKE FOR MORE UNSTABLE CONDITIONS WHICH SPREAD ACRS THE CWFA.
COLD FRONT ASSOC WITH THE LOW CONTINUES TO APPROACH MON NIGHT BUT
APPRECIABLE COLD ADVECTION DOES NOT ARRIVE UNTIL NEAR DAYBREAK TUE.
WHILE MOIST PROFILES MAY STILL BE PRESENT MON NIGHT...CONVECTION
GENERALLY LOOKS TO WANE WITH THE LOSS OF HEATING. THREATS WILL
PRIMARILY BE HEAVY RAIN EACH DAY...WITH PWAT VALUES PROGGED TO BE
ABOVE THE 75TH PERCENTILE AND WEAK FLOW IMPLYING SLOW MOVING STORMS.
THE UPSIDE OF THE MOIST PROFILES IS THAT DOWNBURST THREAT WILL BE
FAIRLY LOW. TEMPS TREND UPWARD FROM SUN TO MON BUT WITH AFTN MAXES
SEVERAL DEGREES ABOVE CLIMO BOTH DAYS.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 250 AM SAT...AS SFC LOW MOVES ACRS QUEBEC TUESDAY...COLD FRONT
WILL MOVE OFF THE MID-ATLANTIC COAST. ASSOCIATED CONVERGENCE ZONE
WILL LIKELY ENHANCE CONVECTIVE COVERAGE OVER OUR PIEDMONT REGION
WHERE SIMILAR INSTABILITY WILL BE IN PLAY COMPARED TO THAT OF MONDAY.
HOWEVER THE MTNS WILL SEE LESS UNSTABLE CONDITIONS ON ACCOUNT OF THE
INCOMING CONTINENTAL AIRMASS. BY WED THIS WILL HAVE SPREAD ACROSS THE
WHOLE CWFA. DRY AND SETTLED WEATHER MAY BE SHORT LIVED AS THE NRN
STREAM CONTINUES TO FEATURE A TROUGH TO OUR NORTH LATE IN THE
WEEK...AROUND WHICH DISTURBANCES OR MINOR SHORTWAVES WILL PASS ATOP A
WEAK STATIONARY BOUNDARY ON THE SRN FRINGE OF THE HIGH. THIS WILL
BRING SMALL PRECIP CHANCES BACK THU...GFS AND EC SHOWING SOME
DIFFERENCES /AND RUN-TO-RUN VARIATION/ IN EXACTLY WHERE THAT BOUNDARY
SETS UP. INSTABILITY WILL REMAIN ON ITS WARM SIDE SUPPORTING POPS
EVEN IF ANY UPGLIDE OVER IT IS TOO WEAK. DIURNAL INSTABILITY LOOKS TO
RETURN BY FRIDAY ANYWAY AS POPS AGAIN EXHIBIT A CLIMATOLOGICAL FOCUS
ON THE MTNS. CONFIDENCE IS LOW ON THE TEMP FCST...WITH A COOLING
TREND AND RETURN TO NEAR-NORMAL READINGS LIKELY IF THE BOUNDARY
SETTLES PAST THE AREA...BUT ABOVE NORMAL MAX TEMPS CONTINUING IF IT
STALLS TO THE NORTH.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...AN MVFR DECK HAS FORMED OVERHEAD...BUT IT SHOULD BE FAIRLY
SHORT LIVED SINCE IT HAS LIMITED SPATIAL EXTENT AND RAP PROFILES
DISSIPATE THE LOW LEVEL MOISTURE QUICKLY THROUGH 14Z.
OTHERWISE...EXPECT MAINLY SCT TO BKN HIGHER LEVEL VFR CLOUDS
SPILLING OVER THE RIDGE THROUGH THE PERIOD...WITH CONVECTIVE CUMULUS
FILLING IN AT 5 TO 6 KFT DURING THE PEAK HEATING HOURS. SURFACE
WINDS WILL REMAIN SOLIDLY S TO SW AT SPEEDS LESS THAN 10 KT. MODEL
PROFILES ALL STILL EXHIBIT A WEAK SUBSIDENCE CAP WHICH WILL LIMIT
ANY PIEDMONT CONVECTION.
ELSEWHERE...KAVL WILL SEE A CHANCE OF A SHOWER OR LATE DAY
THUNDERSTORM...BUT WITH SLIGHTLY MORE CAPPING IN PROFILES
DIMINISHING THE CHANCES FARTHER EAST OVER THE FOOTHILLS. EXPECT OCNL
VFR CIGS THROUGHOUT...WITH MID AND HIGH LEVEL CIGS TOPPING THE UPPER
RIDGE AXIS EARLY AND LATE...AND PERHAPS CONVECTIVE CUMULUS CIGS AT 5
TO 6 KFT WITH PEAK HEATING. SRLY WINDS WILL REMAIN 10 KT OR LESS
THROUGH THE PERIOD. BRIEF FOG IS POSSIBLE MAINLY NEAR KHKY AROUND
DAYBREAK THIS MORNING...AND AT KAVL LATE TONIGHT.
OUTLOOK...A PLUME OF MOISTURE FROM THE GULF OF MEXICO WILL INCREASE
ACROSS THE REGION THROUGH EARLY NEXT WEEK. RESTRICTIONS FROM STRATUS
AND/OR FOG COULD DEVELOP DURING THE PRE/DAWN HOURS EACH MORNING
ACROSS AREAS THAT RECEIVED RAIN THE PREVIOUS AFTERNOON OR EVENING.
CONFIDENCE TABLE...
11-17Z 17-23Z 23-05Z 05-06Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 94% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 94% 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...WIMBERLEY
NEAR TERM...HG
SHORT TERM...WIMBERLEY
LONG TERM...WIMBERLEY
AVIATION...HG
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1250 PM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 1059 AM CDT SAT MAY 16 2015
MESSY DAY AHEAD AS A SMALL MCS EXITS TO THE NORTH LEAVING BEHIND
EASTERLY FLOW IN THE FAR NORTHERN CWA. JET MAX LIFTING NORTH OVER
THE WESTERN HIGH PLAINS WILL SWING THROUGH THE ENTRANCE REGION
THIS AFTERNOON AND SOME EFFECTS OF THAT MAY ALREADY BE SHOWING UP.
A SMALL POSSIBLE MCV IS LIFTING NORTH INTO NORTH CENTRAL NEBRASKA
AND WILL LIFT THROUGH THE CWA EARLY THIS AFTERNOON. A HANDFUL OF
THE HIGH RESOLUTION MODELS INDICATING SCATTERED THUNDERSTORMS
POSSIBLE BETWEEN ABOUT THE JAMES RIVER AND INTERSTATE 29 AND
SUSPECT IT IS ASSOCIATED WITH THIS FEATURE. NOT SURE HOW MUCH TO
REALLY BITE ON THIS RIGHT NOW. IF THESE STORMS CAN DEVELOP AN
ISOLATED SEVERE STORM WOULD BE POSSIBLE BUT WITH CAPE VALUES
FAIRLY LOW...AROUND 1000 J/KG...MAINLY LOOKING AT QUARTERS AND 60
MPH WINDS.
IF THIS SMALL MCV FEATURE DOES NOT SET ANY ACTIVITY OFF THE FLOW
IS NOT REALLY CONVERGENT AT ALL AND WOULD EXPECT A BETTER CHANCE TO
THE WEST OF OUR AREA AND OF COURSE TO THE SOUTH. THE ACTIVITY TO
THE SOUTH WILL BE THE MOST IMPORTANT TO WATCH AS THAT WILL LIKELY
ADVECT/DEVELOP NORTH THROUGH THE EVENING. AGAIN...INSTABILITY
MARGINAL SO QUARTERS TO MAYBE HALF DOLLARS WILL BE THE MAIN
THREAT. WILL ALSO NEED TO WATCH FOR A SMALL CHANCE FOR SOME FLASH
FLOODING...ESPECIALLY FAR SOUTHEAST SD...NORTHWEST IA AND
SOUTHWEST MN WHERE HEAVY RAIN HAS FALLEN AS OF LATE AND OR THE
MODELS ARE HINTING AT SOME HIGHER RAINFALL POTENTIAL. THE 3 HOUR
FLASH FLOOD GUIDANCE IN THESE LOCATIONS RUNNING GENERALLY LESS
THAN 2 INCHES.
WILL PROBABLY DECREASE POPS A BIT THIS AFTERNOON AND FOCUS BEST
CHANCES AFTER ABOUT 2-4Z.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT SAT MAY 16 2015
TRICKY FORECAST FOR TODAY...WITH UNSETTLED WEATHER CONDITIONS
PERSISTING FOR MUCH OF THE DAY AND INTO TONIGHT. MAIN CONCERN IS HOW
THE ONGOING THUNDERSTORM ACTIVITY WILL IMPACT TEMPERATURES AND
SEVERE STORM CHANCES LATER ON TODAY.
SURFACE LOW PRESSURE HAS DEEPENED OVER THE BLACK HILLS EARLY THIS
MORNING AND IS SLOWLY DRIFTING NORTHWARD. SEVERAL BANDS OF
THUNDERSTORMS ARE LIFTING NORTHWARD WITH THE ADVANCING WARM FRONT
NEAR THE NEBRASKA AND SOUTH DAKOTA BORDER. THE MOST RECENT RUNS OF
THE HRRR SEEM TO HAVE A GOOD HANDLE ON THIS ACTIVITY...WHICH SHOULD
CONTINUE LIFTING NORTHEAST THROUGH AROUND MID MORNING...LOSING
INTENSITY AS THE NIGHT PROGRESSES. THINK THAT IN GENERAL THERE WILL
BE A LULL IN PRECIPITATION ACTIVITY AROUND LATE MORNING AND MIDDAY
BEFORE SCATTERED STORMS IGNITE AGAIN IN THE AFTERNOON AS THE
STRONGER WAVE PIVOTS INTO THE MISSOURI VALLEY. DEWPOINTS SHOULD
REACH THE LOW TO MID 60S ACROSS THE REGION BUT THE QUESTION IS HOW
MUCH DESTABILIZATION WILL BE POSSIBLE WITH CLOUD DEBRIS FROM MORNING
CONVECTION AND HOW THIS WILL IMPACT TEMPERATURES. IF SOME CLEARING
AND DESTABILIZATION OCCURS...SEVERE STORMS WILL BECOME POSSIBLE.
COULD SEE CAPE VALUES AS HIGH AS 1000 TO 1500 J/KG WITH DECENT
SHEAR. MAIN SEVERE THREATS WILL BE HAIL TO HALF DOLLAR SIZE AND WIND
GUSTS TO 65 MPH. TORNADIC THREAT IS VERY LOW WITH THE WARM FRONT
LIKELY NORTH OF THE FORECAST AREA...BUT COULD BE LOCALIZED IF THE
FRONT LAGS AT STORM INITIALIZATION. AGAIN...IF WEAKER
DESTABILIZATION OCCURS...THE SEVERE THREAT WILL ALSO DIMINISH FOR
THIS AFTERNOON AND EVENING.
EXPECT STORMS TO BECOME WIDESPREAD LATE AFTERNOON INTO THE
EVENING...WITH THE ARRIVAL OF THE JET MAX...FOLLOWED BY THE UPPER
LOW CENTER LIFTING INTO THE WESTERN FORECAST AREA OVERNIGHT. SEVERE
THREAT DIMINISHES LATE EVENING BUT WITH MULTIPLE CLUSTERS OF STORMS
LIFTING NORTH NORTHEAST THROUGH THE REGION...A GOOD SOAKING RAIN IS
EXPECTED FOR THE REGION. LOOKS LIKE AROUND A HALF INCH TO A LITTLE
OVER AN INCH IS POSSIBLE THROUGH TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 340 AM CDT SAT MAY 16 2015
STILL THINK THE NAM...LIKE A DAY AGO...IS A LITTLE TOO SLOW BRINGING
THE UPPER LOW NORTH ACROSS THE AREA. THE GFS AND EC LOOK BETTER BUT
THERE ARE DETAIL DIFFERENCES BETWEEN THESE MODELS ON PRECIPITATION
THREAT AS THE LOW MOVES NORTH. HAVE DECIDED TO KEEP A GENERAL
RAINFALL PATTERN FOCUSING ON OUR NORTHWEST EARLY WITH PRECIPITATION
THREAT AND AMOUNTS DECREASING SOUTH TO NORTH DURING THE DAY. THIS IS
NOT FAR FROM AN EC/GFS CONSENSUS. THE BIG QUESTION IS WILL THERE BE
A N/S BAND/LINE OF DECENT CONVECTION STILL GOING ON INTO THE MORNING
OVER THE EASTERN EDGE OF THE AREA...GOING WITH THE CONSENSUS THAT
MOST OF THIS WOULD BE DURING THE NIGHT AND BEGINNING TO MOVE NORTH
OF THE AREA.
AS FAR WEST AS THE LOW TRACK LOOKS...SURFACE WINDS WILL NOT BE GOING
WESTERLY UNTIL FAIRLY LATE IN THE DAY. TEMPERATURES SHOULD REACH THE
70S EAST TO THE 60S WEST.
THE SYSTEM SHOULD SLOWLY PULL OUT TO THE NORTHEAST SUNDAY NIGHT AND
HAVE A SHOWER THREAT DECREASING FROM SOUTHWEST TO NORTHEAST. IT DOES
LOOK WINDY RIGHT BEHIND THE LOW SUNDAY NIGHT. TEMPERATURES BY EARLY
MONDAY MORNING SHOULD DROP INTO THE UPPER 30S TO LOWER 40S.
MONDAY LOOKS COOL AND BREEZY TO WINDY. MODELS HINT AT A WEAK
SECONDARY SHORT WAVE DROPPING DOWN BEHIND THE MAIN SYSTEM. WITH COOL
AIR ALOFT A FEW LIGHT SHOWERS WOULD BE POSSIBLE AND LOW CLOUD COVER
SHOULD LINGER MUCH OF THE DAY ESPECIALLY NORTH. SUBSIDENCE BEHIND THE
LOW SHOULD COUNTER THIS AND MODEL INDICATIONS OF SOLID CLOUDS
LINGERING MOST OF THE DAY ARE PROBABLY OVERDONE. FOR THE SAME REASON
WILL LEAVE OUT ANY SHOWER OR SPRINKLE MENTION FOR NOW. DAYTIME HIGHS
WILL BE HELD TO THE MID 40S NORTHEAST TO THE MID 50S SOUTHWEST.
HIGH PRESSURE WILL BRING CLEARING BY MONDAY NIGHT AND A FAIRLY
BRIGHT DAY TUESDAY...THOUGH CLOUDS WILL BEGIN TO INCREASE FROM THE
SOUTHWEST BY LATE TUESDAY AS ONE IN A SERIES OF SHORT WAVES COMES UP
FROM THE SOUTHWESTERN USA TROUGH POSITION. THIS WILL BRING A THREAT
OF RAIN ESPECIALLY SOUTHWEST CENTERED ON WEDNESDAY...AND
TEMPERATURES WILL STILL BE COOL. AFTER A SHORT BREAK THURSDAY...A
CHANCE OF THUNDERSTORMS WILL DEVELOP AS THE WEEKEND APPROACHES AND A
STRONGER WAVE COMES UP. TEMPERATURES SHOULD BE WARMING A LITTLE BY
THE END OF THE WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1246 PM CDT SAT MAY 16 2015
MVFR CEILINGS WILL LIFT NORTH THROUGH THE AFTERNOON...BUT MAY
AGAIN REDEVELOP AFTER SUNSET AS MIXING DECREASES AND THE INVERSION
STRENGTHENS AGAIN. BACKED OFF ON THUNDERSTORM CHANCES THIS
AFTERNOON AND EVENING BUT WILL STILL BRING A GOOD CHANCES FOR
THUNDERSTORMS THROUGH FROM ABOUT 4Z THROUGH 12Z. AT THIS TIME NOT
EXPECTING MORE THAN ISOLATED SEVERE STORMS BUT THERE COULD BE
QUITE A FEW STORMS CAPABLE OF LIGHTNING...SMALL HAIL AND HEAVY
RAINFALL.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...08
SHORT TERM...
LONG TERM...
AVIATION...08
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1241 PM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 1159 AM CDT SAT MAY 16 2015
MUCH UNCERTAINTY OVER SEVERE WEATHER POTENTIAL THIS AFTERNOON
THANKS MAINLY TO CLOUD COVER. WARM FRONT CONTINUES TO SLOWLY LIFT
ACROSS THE CWA...PROVIDING A NARROW RIBBON OF FAVORABLE SEVERE
WEATHER PARAMETERS...AND AS A FOCUS FOR AROUND 1000 J/KG CAPE.
HOWEVER HRRR AND NSSL WRF TEND TO GENERATE SPOTTY CONVECTION
ACROSS THE CWA IN THE AFTERNOON/EVENING...WHICH MAY BE AN
ARTIFACT OF THE WEAK UPPER SUPPORT AND INHIBITION FROM CLOUD
COVER. DESPITE THESE RESERVATIONS...LOW LEVEL SHEAR AND LOW LCLS
SUPPORT CONTINUED MONITORING FOR A SEVERE WEATHER THREAT AND
MENTION IN ZONE. THE MAIN SHORTWAVE LIFTING NORTH TOWARDS SUNDAY
AM IS ASSOCIATED WITH THE BEST JET DYNAMICS...AND SREF
PROBABILITIES FOR HEAVY RAIN ARE QUITE HIGH.
&&
.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 435 AM CDT SAT MAY 16 2015
AN ACTIVE WEATHER PATTERN EXPECTED OVER THE SHORT TERM PERIOD!
INITIAL CONCERNS ARE SEVERE WEATHER AND HEAVY RAIN POTENTIAL TODAY
AND TONIGHT. ADDITIONAL PRECIPITATION /AND SNOW?/ ALONG WITH
POSSIBLE FREEZING TEMPERATURES FOLLOW ON SUNDAY AND MONDAY.
TODAY AND TONIGHT...FORECASTER CONFIDENCE: MODERATE
UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY CLEARLY DEPICTED A STRONG
CLOSED LOW SPINNING OVER THE INTERMOUNTAIN WEST. SEVERAL SHORTWAVES
ARE EXPECTED TO MOVE THROUGH THE REGION THE NEXT DAY OR
SO...PROVIDING THE IMPETUS FOR SEVERAL ROUNDS OF THUNDERSTORM
DEVELOPMENT. INITIAL ROUND OF SHOWERS AND STORMS IS CURRENTLY MOVING
NEWD ACROSS THE CWA PER STOUT LLJ. NOTHING SEVERE WITH THIS
ACTIVITY...ALTHOUGH BRIEF HEAVY RAINFALL AND GUSTY WINDS ARE
POSSIBLE. IN FACT...SEVERAL OBS HAVE NOTED A WEAK "WAKE LOW"
ACROSS WESTERN SD.
IN THE WAKE OF THIS MORNING ACTIVITY...THERE IS STILL A FAIR AMOUNT
OF UNCERTAINTY FOR THE AFTERNOON...MAINLY WITH REGARDS TO
DESTABILIZATION. SEVERAL MODEL SOLUTIONS KEEP PERSISTENT CLOUDS AND
ELEVATED...WEAK THUNDERSTORMS IN THE AREA THROUGHOUT THE DAY. THIS
OUTCOME WOULD LIMIT ANY SEVERE THUNDERSTORM THREAT. OTHER SOLUTIONS
INDICATE A LULL IN PCPN...WITH AT LEAST PARTIAL SUNSHINE AND MORE
SIGNIFICANT INSTABILITY. AT THIS TIME...TRENDED THE FORECAST MORE
TOWARD THE LATER SOLUTION AND FEEL AT LEAST POCKETS OF MLCAPE OF 500-
1500 J/KG WILL DEVELOP IN CONCERT WITH WITH DEEP LAYER SHEAR VALUES
OF 30-40KTS BY 18Z. THUS...BELIEVE WE WILL SEE SCATTERED CONVECTION
RE-DEVELOP BETWEEN 18Z AND 21Z /PER LATEST HRRR SOLUTIONS/ WITH SOME
OF THESE STORMS BECOMING STRONG TO SEVERE. MAIN THREAT WOULD BE
HAIL AND DAMAGING WINDS...ALTHOUGH ANY OUTFLOW BOUNDARIES OR BACKED
SFC FLOW COULD ALSO PROVIDE ENOUGH SRH FOR AN ISOLATED TORNADO.
CORFIDI VECTORS ARE ALSO INDICATING RELATIVELY SLOW STORM
MOVEMENT...SO KEPT THE MENTION OF LOCALLY HEAVY RAINFALL AS WELL. A
STRONGER SHORTWAVE/PV ANOMALY WILL EJECT ACROSS THE NRN PLAINS
TONIGHT...LIKELY MAINTAINING OR INITIATING NEW TSTMS. SPC MAINTAINED
A SLIGHT RISK FOR THE ENTIRE AREA IN THE DAY 1 OUTLOOK...AND THIS
APPEARS REASONABLE.
SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE: MODERATE
AS MENTIONED PREVIOUSLY...THE TRACK OF THIS SYSTEM HAS IN FACT
SLOWED DOWN SUCH THAT A LINGERING SEVERE THREAT WILL CONTINUE ON
SUNDAY...MAINLY ALONG AND EAST OF THE JAMES RIVER VALLEY /IN THE
WARM SECTOR/. ALTHOUGH DEEP LAYER SHEAR WILL BE MARGINAL...SFC
VORTICITY INVOF OF THE SFC LOW COULD YIELD ANOTHER ROUND OF STRONG
TO SEVERE STORMS...AND POSSIBLE LANDSPOUT TYPE STORMS. DEFORMATION
ZONE PCPN IS EXPECTED NW OF THE SFC CYCLONE...WITH 00Z SUITE OF
MODELS INDICATING THE POTENTIAL FOR ADDITIONAL SIGNIFICANT
RAINFALL. FINALLY...IN THE WAKE OF THIS SYSTEM...A UNSEASONABLY
COLD AIRMASS WILL FILTER IN FROM THE NORTHWEST. 850MB/925MB TEMPS
ARE FORECAST TO FALL BELOW ZERO CELSIUS...WITH THE POSSIBILITY OF
A RAIN/SNOW MIX ACROSS N-CENTRAL SD. YES...I SAID A RAIN/SNOW MIX ON
MAY 16TH...UGH. PLENTY OF TIME TO FINE TUNE THIS FORECAST.
.LONG TERM...(MONDAY EVENING THROUGH FRIDAY)
ISSUED AT 435 AM CDT SAT MAY 16 2015
COOL CANADIAN HIGH PRESSURE WILL BE BUILDING SOUTH OVER THE REGION
MONDAY NIGHT INTO TUESDAY MORNING TO START OFF THE EXTENDED PERIOD.
LOOKING FOR RATHER COOL OVERNIGHT LOWS MONDAY NIGHT/TUESDAY MORNING
WITH READINGS AROUND FREEZING OR SLIGHTLY COOLER. ITS LOOKING LIKE
IT MAY NOT BE QUITE AS COLD AS PREVIOUSLY THOUGHT AS THERE IS STILL
A PRESSURE GRADIENT OVERHEAD BY 12Z TUESDAY WHICH WILL KEEP A BIT OF
A BREEZE GOING. NONETHELESS...THREAT FOR FROST/FREEZE CONDITIONS
STILL POSSIBLE TUESDAY MORNING AND STILL POSSIBLE FOR SFC HIGH TO BE
MORE OF AN INFLUENCE WITH WEAKER WINDS BEING THE CASE.
THE HIGH PRESSURE LINGERS OVER THE NORTHERN PLAINS DURING THE FIRST
PART OF THE EXTENDED...KEEPING COOL TEMPS OVER THE REGION THROUGH
MID WEEK. HIGHS ARE ONLY EXPECTED TO BE IN THE 50S TO LOW 60S WHICH
IS WELL BELOW NORMAL FOR THIS TIME OF YEAR. MODELS ALSO SHOWING SOME
SHORTWAVE ENERGY WORKING ACROSS THE CENTRAL/NORTHERN PLAINS TUESDAY
NIGHT THROUGH WEDNESDAY NIGHT...BUT IT WILL BE RUNNING INTO DRIER
AIR ASSOCIATED WITH THE HIGH. APPEARS BEST CHANCES FOR PRECIP WILL
BE OVER THE WEST/SOUTHWEST CWA.
MODELS SHOW WARMING TEMPS BY THE END OF THE UPCOMING WEEK WITH HIGHS
RETURNING CLOSER TO NORMAL BY FRIDAY. LOOKING WAY OUT...MODELS
TRYING TO SHOW ANOTHER SIGNIFICANT STORM SYSTEM POSSIBLY AFFECTING
THE REGION NEXT WEEKEND AS THE ACTIVE WEATHER PATTERN CONTINUES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1231 PM CDT SAT MAY 16 2015
MAINLY VFR OR PERHAPS OCCASIONALLY MVFR CONDITIONS ON
SOUTH/SOUTHEASTERLY WINDS WILL BE THE RULE OVER THE NEXT 12 HOURS
AT LEAST. ANY CONVECTION WILL LIKELY KNOCK THAT DOWN INTO IFR
RANGE DUE TO VISBY/CIG RESTRAINTS IN HEAVIER DOWNPOURS. CONVECTION
TODAY/TONIGHT WILL HAVE THE ABILITY TO PRODUCE LARGE
HAIL...DAMAGING WINDS AND PERHAPS EVEN A BRIEF TORNADO. LATER
TONIGHT INTO SUNDAY...STRONG NORTH/NORTHWEST WINDS WILL DEVELOP
OVER THE KPIR AND KMBG TERMINALS WHILE A BROAD BAND OF MODERATE TO
OCCASIONALLY HEAVY RAIN SHOWERS AND EMBEDDED THUNDER LIFTS UP
ACROSS THE REGION...LIKELY AFFECTING ALL FOUR TERMINALS AT SOME
POINT HEADING INTO SUNDAY MORNING.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...CONNELLY
SHORT TERM...FOWLE
LONG TERM...TMT
AVIATION...DORN
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
1224 PM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 1159 AM CDT SAT MAY 16 2015
MUCH UNCERTAINTY OVER SEVERE WEATHER POTENTIAL THIS AFTERNOON
THANKS MAINLY TO CLOUD COVER. WARM FRONT CONTINUES TO SLOWLY LIFT
ACROSS THE CWA...PROVIDING A NARROW RIBBON OF FAVORABLE SEVERE
WEATHER PARAMETERS...AND AS A FOCUS FOR AROUND 1000 J/KG CAPE.
HOWEVER HRRR AND NSSL WRF TEND TO GENERATE SPOTTY CONVECTION
ACROSS THE CWA IN THE AFTERNOON/EVENING...WHICH MAY BE AN
ARTIFACT OF THE WEAK UPPER SUPPORT AND INHIBITION FROM CLOUD
COVER. DESPITE THESE RESERVATIONS...LOW LEVEL SHEAR AND LOW LCLS
SUPPORT CONTINUED MONITORING FOR A SEVERE WEATHER THREAT AND
MENTION IN ZONE. THE MAIN SHORTWAVE LIFTING NORTH TOWARDS SUNDAY
AM IS ASSOCIATED WITH THE BEST JET DYNAMICS...AND SREF
PROBABILITIES FOR HEAVY RAIN ARE QUITE HIGH.
UPDATE ISSUED AT 647 AM CDT SAT MAY 16 2015
AVIATION DISCUSSION UPDATED BELOW FOR 12Z TAFS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 435 AM CDT SAT MAY 16 2015
AN ACTIVE WEATHER PATTERN EXPECTED OVER THE SHORT TERM PERIOD!
INITIAL CONCERNS ARE SEVERE WEATHER AND HEAVY RAIN POTENTIAL TODAY
AND TONIGHT. ADDITIONAL PRECIPITATION /AND SNOW?/ ALONG WITH
POSSIBLE FREEZING TEMPERATURES FOLLOW ON SUNDAY AND MONDAY.
TODAY AND TONIGHT...FORECASTER CONFIDENCE: MODERATE
UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY CLEARLY DEPICTED A STRONG
CLOSED LOW SPINNING OVER THE INTERMOUNTAIN WEST. SEVERAL SHORTWAVES
ARE EXPECTED TO MOVE THROUGH THE REGION THE NEXT DAY OR
SO...PROVIDING THE IMPETUS FOR SEVERAL ROUNDS OF THUNDERSTORM
DEVELOPMENT. INITIAL ROUND OF SHOWERS AND STORMS IS CURRENTLY MOVING
NEWD ACROSS THE CWA PER STOUT LLJ. NOTHING SEVERE WITH THIS
ACTIVITY...ALTHOUGH BRIEF HEAVY RAINFALL AND GUSTY WINDS ARE
POSSIBLE. IN FACT...SEVERAL OBS HAVE NOTED A WEAK "WAKE LOW"
ACROSS WESTERN SD.
IN THE WAKE OF THIS MORNING ACTIVITY...THERE IS STILL A FAIR AMOUNT
OF UNCERTAINTY FOR THE AFTERNOON...MAINLY WITH REGARDS TO
DESTABILIZATION. SEVERAL MODEL SOLUTIONS KEEP PERSISTENT CLOUDS AND
ELEVATED...WEAK THUNDERSTORMS IN THE AREA THROUGHOUT THE DAY. THIS
OUTCOME WOULD LIMIT ANY SEVERE THUNDERSTORM THREAT. OTHER SOLUTIONS
INDICATE A LULL IN PCPN...WITH AT LEAST PARTIAL SUNSHINE AND MORE
SIGNIFICANT INSTABILITY. AT THIS TIME...TRENDED THE FORECAST MORE
TOWARD THE LATER SOLUTION AND FEEL AT LEAST POCKETS OF MLCAPE OF 500-
1500 J/KG WILL DEVELOP IN CONCERT WITH WITH DEEP LAYER SHEAR VALUES
OF 30-40KTS BY 18Z. THUS...BELIEVE WE WILL SEE SCATTERED CONVECTION
RE-DEVELOP BETWEEN 18Z AND 21Z /PER LATEST HRRR SOLUTIONS/ WITH SOME
OF THESE STORMS BECOMING STRONG TO SEVERE. MAIN THREAT WOULD BE
HAIL AND DAMAGING WINDS...ALTHOUGH ANY OUTFLOW BOUNDARIES OR BACKED
SFC FLOW COULD ALSO PROVIDE ENOUGH SRH FOR AN ISOLATED TORNADO.
CORFIDI VECTORS ARE ALSO INDICATING RELATIVELY SLOW STORM
MOVEMENT...SO KEPT THE MENTION OF LOCALLY HEAVY RAINFALL AS WELL. A
STRONGER SHORTWAVE/PV ANOMALY WILL EJECT ACROSS THE NRN PLAINS
TONIGHT...LIKELY MAINTAINING OR INITIATING NEW TSTMS. SPC MAINTAINED
A SLIGHT RISK FOR THE ENTIRE AREA IN THE DAY 1 OUTLOOK...AND THIS
APPEARS REASONABLE.
SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE: MODERATE
AS MENTIONED PREVIOUSLY...THE TRACK OF THIS SYSTEM HAS IN FACT
SLOWED DOWN SUCH THAT A LINGERING SEVERE THREAT WILL CONTINUE ON
SUNDAY...MAINLY ALONG AND EAST OF THE JAMES RIVER VALLEY /IN THE
WARM SECTOR/. ALTHOUGH DEEP LAYER SHEAR WILL BE MARGINAL...SFC
VORTICITY INVOF OF THE SFC LOW COULD YIELD ANOTHER ROUND OF STRONG
TO SEVERE STORMS...AND POSSIBLE LANDSPOUT TYPE STORMS. DEFORMATION
ZONE PCPN IS EXPECTED NW OF THE SFC CYCLONE...WITH 00Z SUITE OF
MODELS INDICATING THE POTENTIAL FOR ADDITIONAL SIGNIFICANT
RAINFALL. FINALLY...IN THE WAKE OF THIS SYSTEM...A UNSEASONABLY
COLD AIRMASS WILL FILTER IN FROM THE NORTHWEST. 850MB/925MB TEMPS
ARE FORECAST TO FALL BELOW ZERO CELSIUS...WITH THE POSSIBILITY OF
A RAIN/SNOW MIX ACROSS N-CENTRAL SD. YES...I SAID A RAIN/SNOW MIX ON
MAY 16TH...UGH. PLENTY OF TIME TO FINE TUNE THIS FORECAST.
.LONG TERM...(MONDAY EVENING THROUGH FRIDAY)
ISSUED AT 435 AM CDT SAT MAY 16 2015
COOL CANADIAN HIGH PRESSURE WILL BE BUILDING SOUTH OVER THE REGION
MONDAY NIGHT INTO TUESDAY MORNING TO START OFF THE EXTENDED PERIOD.
LOOKING FOR RATHER COOL OVERNIGHT LOWS MONDAY NIGHT/TUESDAY MORNING
WITH READINGS AROUND FREEZING OR SLIGHTLY COOLER. ITS LOOKING LIKE
IT MAY NOT BE QUITE AS COLD AS PREVIOUSLY THOUGHT AS THERE IS STILL
A PRESSURE GRADIENT OVERHEAD BY 12Z TUESDAY WHICH WILL KEEP A BIT OF
A BREEZE GOING. NONETHELESS...THREAT FOR FROST/FREEZE CONDITIONS
STILL POSSIBLE TUESDAY MORNING AND STILL POSSIBLE FOR SFC HIGH TO BE
MORE OF AN INFLUENCE WITH WEAKER WINDS BEING THE CASE.
THE HIGH PRESSURE LINGERS OVER THE NORTHERN PLAINS DURING THE FIRST
PART OF THE EXTENDED...KEEPING COOL TEMPS OVER THE REGION THROUGH
MID WEEK. HIGHS ARE ONLY EXPECTED TO BE IN THE 50S TO LOW 60S WHICH
IS WELL BELOW NORMAL FOR THIS TIME OF YEAR. MODELS ALSO SHOWING SOME
SHORTWAVE ENERGY WORKING ACROSS THE CENTRAL/NORTHERN PLAINS TUESDAY
NIGHT THROUGH WEDNESDAY NIGHT...BUT IT WILL BE RUNNING INTO DRIER
AIR ASSOCIATED WITH THE HIGH. APPEARS BEST CHANCES FOR PRECIP WILL
BE OVER THE WEST/SOUTHWEST CWA.
MODELS SHOW WARMING TEMPS BY THE END OF THE UPCOMING WEEK WITH HIGHS
RETURNING CLOSER TO NORMAL BY FRIDAY. LOOKING WAY OUT...MODELS
TRYING TO SHOW ANOTHER SIGNIFICANT STORM SYSTEM POSSIBLY AFFECTING
THE REGION NEXT WEEKEND AS THE ACTIVE WEATHER PATTERN CONTINUES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 647 AM CDT SAT MAY 16 2015
QUITE A VARIATION OF CONDITIONS THROUGH THE TAF FORECAST PERIOD.
THIS MORNING...A MIX OF CIGS ACROSS THE REGION RANGING FROM AROUND
500 FT TO LOW END VFR CONDITIONS. ALSO SEEING SHRA AFFECTING KABR
AND KATY BUT WILL BE ENDING BY 13Z. EXPECTING REDEVELOPMENT OF
SHOWER AND STORM ACTIVITY BY AROUND 18Z AND PERSISTING THROUGH THE
AFTERNOON ACROSS MUCH OF THE FORECAST AREA. HEAVIER STORMS MAY
DROP CIGS INTO MVFR AND VSBY INTO IFR. SEVERE STORMS ARE POSSIBLE
AS WELL AND COULD AFFECT TERMINALS WITH GUSTY SFC WINDS AND HAIL.
LATE T0NIGHT...ANOTHER BATCH OF RAINFALL IS EXPECTED TO MOVE
NORTHWARD INTO THE REGION.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...CONNELLY
SHORT TERM...FOWLE
LONG TERM...TMT
AVIATION...TMT
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1115 AM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 1059 AM CDT SAT MAY 16 2015
MESSY DAY AHEAD AS A SMALL MCS EXITS TO THE NORTH LEAVING BEHIND
EASTERLY FLOW IN THE FAR NORTHERN CWA. JET MAX LIFTING NORTH OVER
THE WESTERN HIGH PLAINS WILL SWING THROUGH THE ENTRANCE REGION
THIS AFTERNOON AND SOME EFFECTS OF THAT MAY ALREADY BE SHOWING UP.
A SMALL POSSIBLE MCV IS LIFTING NORTH INTO NORTH CENTRAL NEBRASKA
AND WILL LIFT THROUGH THE CWA EARLY THIS AFTERNOON. A HANDFUL OF
THE HIGH RESOLUTION MODELS INDICATING SCATTERED THUNDERSTORMS
POSSIBLE BETWEEN ABOUT THE JAMES RIVER AND INTERSTATE 29 AND
SUSPECT IT IS ASSOCIATED WITH THIS FEATURE. NOT SURE HOW MUCH TO
REALLY BITE ON THIS RIGHT NOW. IF THESE STORMS CAN DEVELOP AN
ISOLATED SEVERE STORM WOULD BE POSSIBLE BUT WITH CAPE VALUES
FAIRLY LOW...AROUND 1000 J/KG...MAINLY LOOKING AT QUARTERS AND 60
MPH WINDS.
IF THIS SMALL MCV FEATURE DOES NOT SET ANY ACTIVITY OFF THE FLOW
IS NOT REALLY CONVERGENT AT ALL AND WOULD EXPECT A BETTER CHANCE TO
THE WEST OF OUR AREA AND OF COURSE TO THE SOUTH. THE ACTIVITY TO
THE SOUTH WILL BE THE MOST IMPORTANT TO WATCH AS THAT WILL LIKELY
ADVECT/DEVELOP NORTH THROUGH THE EVENING. AGAIN...INSTABILITY
MARGINAL SO QUARTERS TO MAYBE HALF DOLLARS WILL BE THE MAIN
THREAT. WILL ALSO NEED TO WATCH FOR A SMALL CHANCE FOR SOME FLASH
FLOODING...ESPECIALLY FAR SOUTHEAST SD...NORTHWEST IA AND
SOUTHWEST MN WHERE HEAVY RAIN HAS FALLEN AS OF LATE AND OR THE
MODELS ARE HINTING AT SOME HIGHER RAINFALL POTENTIAL. THE 3 HOUR
FLASH FLOOD GUIDANCE IN THESE LOCATIONS RUNNING GENERALLY LESS
THAN 2 INCHES.
WILL PROBABLY DECREASE POPS A BIT THIS AFTERNOON AND FOCUS BEST
CHANCES AFTER ABOUT 2-4Z.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT SAT MAY 16 2015
TRICKY FORECAST FOR TODAY...WITH UNSETTLED WEATHER CONDITIONS
PERSISTING FOR MUCH OF THE DAY AND INTO TONIGHT. MAIN CONCERN IS HOW
THE ONGOING THUNDERSTORM ACTIVITY WILL IMPACT TEMPERATURES AND
SEVERE STORM CHANCES LATER ON TODAY.
SURFACE LOW PRESSURE HAS DEEPENED OVER THE BLACK HILLS EARLY THIS
MORNING AND IS SLOWLY DRIFTING NORTHWARD. SEVERAL BANDS OF
THUNDERSTORMS ARE LIFTING NORTHWARD WITH THE ADVANCING WARM FRONT
NEAR THE NEBRASKA AND SOUTH DAKOTA BORDER. THE MOST RECENT RUNS OF
THE HRRR SEEM TO HAVE A GOOD HANDLE ON THIS ACTIVITY...WHICH SHOULD
CONTINUE LIFTING NORTHEAST THROUGH AROUND MID MORNING...LOSING
INTENSITY AS THE NIGHT PROGRESSES. THINK THAT IN GENERAL THERE WILL
BE A LULL IN PRECIPITATION ACTIVITY AROUND LATE MORNING AND MIDDAY
BEFORE SCATTERED STORMS IGNITE AGAIN IN THE AFTERNOON AS THE
STRONGER WAVE PIVOTS INTO THE MISSOURI VALLEY. DEWPOINTS SHOULD
REACH THE LOW TO MID 60S ACROSS THE REGION BUT THE QUESTION IS HOW
MUCH DESTABILIZATION WILL BE POSSIBLE WITH CLOUD DEBRIS FROM MORNING
CONVECTION AND HOW THIS WILL IMPACT TEMPERATURES. IF SOME CLEARING
AND DESTABILIZATION OCCURS...SEVERE STORMS WILL BECOME POSSIBLE.
COULD SEE CAPE VALUES AS HIGH AS 1000 TO 1500 J/KG WITH DECENT
SHEAR. MAIN SEVERE THREATS WILL BE HAIL TO HALF DOLLAR SIZE AND WIND
GUSTS TO 65 MPH. TORNADIC THREAT IS VERY LOW WITH THE WARM FRONT
LIKELY NORTH OF THE FORECAST AREA...BUT COULD BE LOCALIZED IF THE
FRONT LAGS AT STORM INITIALIZATION. AGAIN...IF WEAKER
DESTABILIZATION OCCURS...THE SEVERE THREAT WILL ALSO DIMINISH FOR
THIS AFTERNOON AND EVENING.
EXPECT STORMS TO BECOME WIDESPREAD LATE AFTERNOON INTO THE
EVENING...WITH THE ARRIVAL OF THE JET MAX...FOLLOWED BY THE UPPER
LOW CENTER LIFTING INTO THE WESTERN FORECAST AREA OVERNIGHT. SEVERE
THREAT DIMINISHES LATE EVENING BUT WITH MULTIPLE CLUSTERS OF STORMS
LIFTING NORTH NORTHEAST THROUGH THE REGION...A GOOD SOAKING RAIN IS
EXPECTED FOR THE REGION. LOOKS LIKE AROUND A HALF INCH TO A LITTLE
OVER AN INCH IS POSSIBLE THROUGH TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 340 AM CDT SAT MAY 16 2015
STILL THINK THE NAM...LIKE A DAY AGO...IS A LITTLE TOO SLOW BRINGING
THE UPPER LOW NORTH ACROSS THE AREA. THE GFS AND EC LOOK BETTER BUT
THERE ARE DETAIL DIFFERENCES BETWEEN THESE MODELS ON PRECIPITATION
THREAT AS THE LOW MOVES NORTH. HAVE DECIDED TO KEEP A GENERAL
RAINFALL PATTERN FOCUSING ON OUR NORTHWEST EARLY WITH PRECIPITATION
THREAT AND AMOUNTS DECREASING SOUTH TO NORTH DURING THE DAY. THIS IS
NOT FAR FROM AN EC/GFS CONSENSUS. THE BIG QUESTION IS WILL THERE BE
A N/S BAND/LINE OF DECENT CONVECTION STILL GOING ON INTO THE MORNING
OVER THE EASTERN EDGE OF THE AREA...GOING WITH THE CONSENSUS THAT
MOST OF THIS WOULD BE DURING THE NIGHT AND BEGINNING TO MOVE NORTH
OF THE AREA.
AS FAR WEST AS THE LOW TRACK LOOKS...SURFACE WINDS WILL NOT BE GOING
WESTERLY UNTIL FAIRLY LATE IN THE DAY. TEMPERATURES SHOULD REACH THE
70S EAST TO THE 60S WEST.
THE SYSTEM SHOULD SLOWLY PULL OUT TO THE NORTHEAST SUNDAY NIGHT AND
HAVE A SHOWER THREAT DECREASING FROM SOUTHWEST TO NORTHEAST. IT DOES
LOOK WINDY RIGHT BEHIND THE LOW SUNDAY NIGHT. TEMPERATURES BY EARLY
MONDAY MORNING SHOULD DROP INTO THE UPPER 30S TO LOWER 40S.
MONDAY LOOKS COOL AND BREEZY TO WINDY. MODELS HINT AT A WEAK
SECONDARY SHORT WAVE DROPPING DOWN BEHIND THE MAIN SYSTEM. WITH COOL
AIR ALOFT A FEW LIGHT SHOWERS WOULD BE POSSIBLE AND LOW CLOUD COVER
SHOULD LINGER MUCH OF THE DAY ESPECIALLY NORTH. SUBSIDENCE BEHIND THE
LOW SHOULD COUNTER THIS AND MODEL INDICATIONS OF SOLID CLOUDS
LINGERING MOST OF THE DAY ARE PROBABLY OVERDONE. FOR THE SAME REASON
WILL LEAVE OUT ANY SHOWER OR SPRINKLE MENTION FOR NOW. DAYTIME HIGHS
WILL BE HELD TO THE MID 40S NORTHEAST TO THE MID 50S SOUTHWEST.
HIGH PRESSURE WILL BRING CLEARING BY MONDAY NIGHT AND A FAIRLY
BRIGHT DAY TUESDAY...THOUGH CLOUDS WILL BEGIN TO INCREASE FROM THE
SOUTHWEST BY LATE TUESDAY AS ONE IN A SERIES OF SHORT WAVES COMES UP
FROM THE SOUTHWESTERN USA TROUGH POSITION. THIS WILL BRING A THREAT
OF RAIN ESPECIALLY SOUTHWEST CENTERED ON WEDNESDAY...AND
TEMPERATURES WILL STILL BE COOL. AFTER A SHORT BREAK THURSDAY...A
CHANCE OF THUNDERSTORMS WILL DEVELOP AS THE WEEKEND APPROACHES AND A
STRONGER WAVE COMES UP. TEMPERATURES SHOULD BE WARMING A LITTLE BY
THE END OF THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 638 AM CDT SAT MAY 16 2015
BROAD AREA OF MVFR AND IFR CONDITIONS ACROSS THE FORECAST AREA
THIS MORNING IN ADDITION TO SCATTERED TSRA TRACKING NORTHEAST
THROUGH THE REGION. EXPECT THIS ACTIVITY TO CONTINUE TO WEAKEN AND
DIMINISH THROUGH 15Z. MODELS SUGGEST THAT SOME IMPROVEMENT TO
CEILINGS FROM SOUTH TO NORTH THROUGH MIDDAY. ADDITIONAL SHOWER AND
THUNDERSTORMS DEVELOPMENT IS EXPECTED IN THE AFTERNOON...BECOMING
MORE WIDESPREAD BY EVENING. TIMING IS A BIT DIFFICULT AT THIS
POINT...BUT HAVE ADDED TSRA MENTION AND LOWER CEILINGS TO TAF
SITES THIS EVENING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...08
SHORT TERM...
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
656 AM CDT SAT MAY 16 2015
.UPDATE...
ISSUED AT 647 AM CDT SAT MAY 16 2015
AVIATION DISCUSSION UPDATED BELOW FOR 12Z TAFS.
&&
.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 435 AM CDT SAT MAY 16 2015
AN ACTIVE WEATHER PATTERN EXPECTED OVER THE SHORT TERM PERIOD!
INITIAL CONCERNS ARE SEVERE WEATHER AND HEAVY RAIN POTENTIAL TODAY
AND TONIGHT. ADDITIONAL PRECIPITATION /AND SNOW?/ ALONG WITH
POSSIBLE FREEZING TEMPERATURES FOLLOW ON SUNDAY AND MONDAY.
TODAY AND TONIGHT...FORECASTER CONFIDENCE: MODERATE
UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY CLEARLY DEPICTED A STRONG
CLOSED LOW SPINNING OVER THE INTERMOUNTAIN WEST. SEVERAL SHORTWAVES
ARE EXPECTED TO MOVE THROUGH THE REGION THE NEXT DAY OR
SO...PROVIDING THE IMPETUS FOR SEVERAL ROUNDS OF THUNDERSTORM
DEVELOPMENT. INITIAL ROUND OF SHOWERS AND STORMS IS CURRENTLY MOVING
NEWD ACROSS THE CWA PER STOUT LLJ. NOTHING SEVERE WITH THIS
ACTIVITY...ALTHOUGH BRIEF HEAVY RAINFALL AND GUSTY WINDS ARE
POSSIBLE. IN FACT...SEVERAL OBS HAVE NOTED A WEAK "WAKE LOW"
ACROSS WESTERN SD.
IN THE WAKE OF THIS MORNING ACTIVITY...THERE IS STILL A FAIR AMOUNT
OF UNCERTAINTY FOR THE AFTERNOON...MAINLY WITH REGARDS TO
DESTABILIZATION. SEVERAL MODEL SOLUTIONS KEEP PERSISTENT CLOUDS AND
ELEVATED...WEAK THUNDERSTORMS IN THE AREA THROUGHOUT THE DAY. THIS
OUTCOME WOULD LIMIT ANY SEVERE THUNDERSTORM THREAT. OTHER SOLUTIONS
INDICATE A LULL IN PCPN...WITH AT LEAST PARTIAL SUNSHINE AND MORE
SIGNIFICANT INSTABILITY. AT THIS TIME...TRENDED THE FORECAST MORE
TOWARD THE LATER SOLUTION AND FEEL AT LEAST POCKETS OF MLCAPE OF 500-
1500 J/KG WILL DEVELOP IN CONCERT WITH WITH DEEP LAYER SHEAR VALUES
OF 30-40KTS BY 18Z. THUS...BELIEVE WE WILL SEE SCATTERED CONVECTION
RE-DEVELOP BETWEEN 18Z AND 21Z /PER LATEST HRRR SOLUTIONS/ WITH SOME
OF THESE STORMS BECOMING STRONG TO SEVERE. MAIN THREAT WOULD BE
HAIL AND DAMAGING WINDS...ALTHOUGH ANY OUTFLOW BOUNDARIES OR BACKED
SFC FLOW COULD ALSO PROVIDE ENOUGH SRH FOR AN ISOLATED TORNADO.
CORFIDI VECTORS ARE ALSO INDICATING RELATIVELY SLOW STORM
MOVEMENT...SO KEPT THE MENTION OF LOCALLY HEAVY RAINFALL AS WELL. A
STRONGER SHORTWAVE/PV ANOMALY WILL EJECT ACROSS THE NRN PLAINS
TONIGHT...LIKELY MAINTAINING OR INITIATING NEW TSTMS. SPC MAINTAINED
A SLIGHT RISK FOR THE ENTIRE AREA IN THE DAY 1 OUTLOOK...AND THIS
APPEARS REASONABLE.
SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE: MODERATE
AS MENTIONED PREVIOUSLY...THE TRACK OF THIS SYSTEM HAS IN FACT
SLOWED DOWN SUCH THAT A LINGERING SEVERE THREAT WILL CONTINUE ON
SUNDAY...MAINLY ALONG AND EAST OF THE JAMES RIVER VALLEY /IN THE
WARM SECTOR/. ALTHOUGH DEEP LAYER SHEAR WILL BE MARGINAL...SFC
VORTICITY INVOF OF THE SFC LOW COULD YIELD ANOTHER ROUND OF STRONG
TO SEVERE STORMS...AND POSSIBLE LANDSPOUT TYPE STORMS. DEFORMATION
ZONE PCPN IS EXPECTED NW OF THE SFC CYCLONE...WITH 00Z SUITE OF
MODELS INDICATING THE POTENTIAL FOR ADDITIONAL SIGNIFICANT
RAINFALL. FINALLY...IN THE WAKE OF THIS SYSTEM...A UNSEASONABLY
COLD AIRMASS WILL FILTER IN FROM THE NORTHWEST. 850MB/925MB TEMPS
ARE FORECAST TO FALL BELOW ZERO CELSIUS...WITH THE POSSIBILITY OF
A RAIN/SNOW MIX ACROSS N-CENTRAL SD. YES...I SAID A RAIN/SNOW MIX ON
MAY 16TH...UGH. PLENTY OF TIME TO FINE TUNE THIS FORECAST.
.LONG TERM...(MONDAY EVENING THROUGH FRIDAY)
ISSUED AT 435 AM CDT SAT MAY 16 2015
COOL CANADIAN HIGH PRESSURE WILL BE BUILDING SOUTH OVER THE REGION
MONDAY NIGHT INTO TUESDAY MORNING TO START OFF THE EXTENDED PERIOD.
LOOKING FOR RATHER COOL OVERNIGHT LOWS MONDAY NIGHT/TUESDAY MORNING
WITH READINGS AROUND FREEZING OR SLIGHTLY COOLER. ITS LOOKING LIKE
IT MAY NOT BE QUITE AS COLD AS PREVIOUSLY THOUGHT AS THERE IS STILL
A PRESSURE GRADIENT OVERHEAD BY 12Z TUESDAY WHICH WILL KEEP A BIT OF
A BREEZE GOING. NONETHELESS...THREAT FOR FROST/FREEZE CONDITIONS
STILL POSSIBLE TUESDAY MORNING AND STILL POSSIBLE FOR SFC HIGH TO BE
MORE OF AN INFLUENCE WITH WEAKER WINDS BEING THE CASE.
THE HIGH PRESSURE LINGERS OVER THE NORTHERN PLAINS DURING THE FIRST
PART OF THE EXTENDED...KEEPING COOL TEMPS OVER THE REGION THROUGH
MID WEEK. HIGHS ARE ONLY EXPECTED TO BE IN THE 50S TO LOW 60S WHICH
IS WELL BELOW NORMAL FOR THIS TIME OF YEAR. MODELS ALSO SHOWING SOME
SHORTWAVE ENERGY WORKING ACROSS THE CENTRAL/NORTHERN PLAINS TUESDAY
NIGHT THROUGH WEDNESDAY NIGHT...BUT IT WILL BE RUNNING INTO DRIER
AIR ASSOCIATED WITH THE HIGH. APPEARS BEST CHANCES FOR PRECIP WILL
BE OVER THE WEST/SOUTHWEST CWA.
MODELS SHOW WARMING TEMPS BY THE END OF THE UPCOMING WEEK WITH HIGHS
RETURNING CLOSER TO NORMAL BY FRIDAY. LOOKING WAY OUT...MODELS
TRYING TO SHOW ANOTHER SIGNIFICANT STORM SYSTEM POSSIBLY AFFECTING
THE REGION NEXT WEEKEND AS THE ACTIVE WEATHER PATTERN CONTINUES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 647 AM CDT SAT MAY 16 2015
QUITE A VARIATION OF CONDITIONS THROUGH THE TAF FORECAST PERIOD.
THIS MORNING...A MIX OF CIGS ACROSS THE REGION RANGING FROM AROUND
500 FT TO LOW END VFR CONDITIONS. ALSO SEEING SHRA AFFECTING KABR
AND KATY BUT WILL BE ENDING BY 13Z. EXPECTING REDEVELOPMENT OF
SHOWER AND STORM ACTIVITY BY AROUND 18Z AND PERSISTING THROUGH THE
AFTERNOON ACROSS MUCH OF THE FORECAST AREA. HEAVIER STORMS MAY
DROP CIGS INTO MVFR AND VSBY INTO IFR. SEVERE STORMS ARE POSSIBLE
AS WELL AND COULD AFFECT TERMINALS WITH GUSTY SFC WINDS AND HAIL.
LATE T0NIGHT...ANOTHER BATCH OF RAINFALL IS EXPECTED TO MOVE
NORTHWARD INTO THE REGION.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...TMT
SHORT TERM...FOWLE
LONG TERM...TMT
AVIATION...TMT
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
649 AM CDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT SAT MAY 16 2015
TRICKY FORECAST FOR TODAY...WITH UNSETTLED WEATHER CONDITIONS
PERSISTING FOR MUCH OF THE DAY AND INTO TONIGHT. MAIN CONCERN IS HOW
THE ONGOING THUNDERSTORM ACTIVITY WILL IMPACT TEMPERATURES AND
SEVERE STORM CHANCES LATER ON TODAY.
SURFACE LOW PRESSURE HAS DEEPENED OVER THE BLACK HILLS EARLY THIS
MORNING AND IS SLOWLY DRIFTING NORTHWARD. SEVERAL BANDS OF
THUNDERSTORMS ARE LIFTING NORTHWARD WITH THE ADVANCING WARM FRONT
NEAR THE NEBRASKA AND SOUTH DAKOTA BORDER. THE MOST RECENT RUNS OF
THE HRRR SEEM TO HAVE A GOOD HANDLE ON THIS ACTIVITY...WHICH SHOULD
CONTINUE LIFTING NORTHEAST THROUGH AROUND MID MORNING...LOSING
INTENSITY AS THE NIGHT PROGRESSES. THINK THAT IN GENERAL THERE WILL
BE A LULL IN PRECIPITATION ACTIVITY AROUND LATE MORNING AND MIDDAY
BEFORE SCATTERED STORMS IGNITE AGAIN IN THE AFTERNOON AS THE
STRONGER WAVE PIVOTS INTO THE MISSOURI VALLEY. DEWPOINTS SHOULD
REACH THE LOW TO MID 60S ACROSS THE REGION BUT THE QUESTION IS HOW
MUCH DESTABILIZATION WILL BE POSSIBLE WITH CLOUD DEBRIS FROM MORNING
CONVECTION AND HOW THIS WILL IMPACT TEMPERATURES. IF SOME CLEARING
AND DESTABILIZATION OCCURS...SEVERE STORMS WILL BECOME POSSIBLE.
COULD SEE CAPE VALUES AS HIGH AS 1000 TO 1500 J/KG WITH DECENT
SHEAR. MAIN SEVERE THREATS WILL BE HAIL TO HALF DOLLAR SIZE AND WIND
GUSTS TO 65 MPH. TORNADIC THREAT IS VERY LOW WITH THE WARM FRONT
LIKELY NORTH OF THE FORECAST AREA...BUT COULD BE LOCALIZED IF THE
FRONT LAGS AT STORM INITIALIZATION. AGAIN...IF WEAKER
DESTABILIZATION OCCURS...THE SEVERE THREAT WILL ALSO DIMINISH FOR
THIS AFTERNOON AND EVENING.
EXPECT STORMS TO BECOME WIDESPREAD LATE AFTERNOON INTO THE
EVENING...WITH THE ARRIVAL OF THE JET MAX...FOLLOWED BY THE UPPER
LOW CENTER LIFTING INTO THE WESTERN FORECAST AREA OVERNIGHT. SEVERE
THREAT DIMINISHES LATE EVENING BUT WITH MULTIPLE CLUSTERS OF STORMS
LIFTING NORTH NORTHEAST THROUGH THE REGION...A GOOD SOAKING RAIN IS
EXPECTED FOR THE REGION. LOOKS LIKE AROUND A HALF INCH TO A LITTLE
OVER AN INCH IS POSSIBLE THROUGH TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 340 AM CDT SAT MAY 16 2015
STILL THINK THE NAM...LIKE A DAY AGO...IS A LITTLE TOO SLOW BRINGING
THE UPPER LOW NORTH ACROSS THE AREA. THE GFS AND EC LOOK BETTER BUT
THERE ARE DETAIL DIFFERENCES BETWEEN THESE MODELS ON PRECIPITATION
THREAT AS THE LOW MOVES NORTH. HAVE DECIDED TO KEEP A GENERAL
RAINFALL PATTERN FOCUSING ON OUR NORTHWEST EARLY WITH PRECIPITATION
THREAT AND AMOUNTS DECREASING SOUTH TO NORTH DURING THE DAY. THIS IS
NOT FAR FROM AN EC/GFS CONSENSUS. THE BIG QUESTION IS WILL THERE BE
A N/S BAND/LINE OF DECENT CONVECTION STILL GOING ON INTO THE MORNING
OVER THE EASTERN EDGE OF THE AREA...GOING WITH THE CONSENSUS THAT
MOST OF THIS WOULD BE DURING THE NIGHT AND BEGINNING TO MOVE NORTH
OF THE AREA.
AS FAR WEST AS THE LOW TRACK LOOKS...SURFACE WINDS WILL NOT BE GOING
WESTERLY UNTIL FAIRLY LATE IN THE DAY. TEMPERATURES SHOULD REACH THE
70S EAST TO THE 60S WEST.
THE SYSTEM SHOULD SLOWLY PULL OUT TO THE NORTHEAST SUNDAY NIGHT AND
HAVE A SHOWER THREAT DECREASING FROM SOUTHWEST TO NORTHEAST. IT DOES
LOOK WINDY RIGHT BEHIND THE LOW SUNDAY NIGHT. TEMPERATURES BY EARLY
MONDAY MORNING SHOULD DROP INTO THE UPPER 30S TO LOWER 40S.
MONDAY LOOKS COOL AND BREEZY TO WINDY. MODELS HINT AT A WEAK
SECONDARY SHORT WAVE DROPPING DOWN BEHIND THE MAIN SYSTEM. WITH COOL
AIR ALOFT A FEW LIGHT SHOWERS WOULD BE POSSIBLE AND LOW CLOUD COVER
SHOULD LINGER MUCH OF THE DAY ESPECIALLY NORTH. SUBSIDENCE BEHIND THE
LOW SHOULD COUNTER THIS AND MODEL INDICATIONS OF SOLID CLOUDS
LINGERING MOST OF THE DAY ARE PROBABLY OVERDONE. FOR THE SAME REASON
WILL LEAVE OUT ANY SHOWER OR SPRINKLE MENTION FOR NOW. DAYTIME HIGHS
WILL BE HELD TO THE MID 40S NORTHEAST TO THE MID 50S SOUTHWEST.
HIGH PRESSURE WILL BRING CLEARING BY MONDAY NIGHT AND A FAIRLY
BRIGHT DAY TUESDAY...THOUGH CLOUDS WILL BEGIN TO INCREASE FROM THE
SOUTHWEST BY LATE TUESDAY AS ONE IN A SERIES OF SHORT WAVES COMES UP
FROM THE SOUTHWESTERN USA TROUGH POSITION. THIS WILL BRING A THREAT
OF RAIN ESPECIALLY SOUTHWEST CENTERED ON WEDNESDAY...AND
TEMPERATURES WILL STILL BE COOL. AFTER A SHORT BREAK THURSDAY...A
CHANCE OF THUNDERSTORMS WILL DEVELOP AS THE WEEKEND APPROACHES AND A
STRONGER WAVE COMES UP. TEMPERATURES SHOULD BE WARMING A LITTLE BY
THE END OF THE WEEK.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 638 AM CDT SAT MAY 16 2015
BROAD AREA OF MVFR AND IFR CONDITIONS ACROSS THE FORECAST AREA
THIS MORNING IN ADDITION TO SCATTERED TSRA TRACKING NORTHEAST
THROUGH THE REGION. EXPECT THIS ACTIVITY TO CONTINUE TO WEAKEN AND
DIMINISH THROUGH 15Z. MODELS SUGGEST THAT SOME IMPROVEMENT TO
CEILINGS FROM SOUTH TO NORTH THROUGH MIDDAY. ADDITIONAL SHOWER AND
THUNDERSTORMS DEVELOPMENT IS EXPECTED IN THE AFTERNOON...BECOMING
MORE WIDESPREAD BY EVENING. TIMING IS A BIT DIFFICULT AT THIS
POINT...BUT HAVE ADDED TSRA MENTION AND LOWER CEILINGS TO TAF
SITES THIS EVENING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...
AVIATION...
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
441 AM CDT SAT MAY 16 2015
.SHORT TERM...(TODAY THROUGH MONDAY AFTERNOON)
ISSUED AT 435 AM CDT SAT MAY 16 2015
AN ACTIVE WEATHER PATTERN EXPECTED OVER THE SHORT TERM PERIOD!
INITIAL CONCERNS ARE SEVERE WEATHER AND HEAVY RAIN POTENTIAL TODAY
AND TONIGHT. ADDITIONAL PRECIPITATION /AND SNOW?/ ALONG WITH
POSSIBLE FREEZING TEMPERATURES FOLLOW ON SUNDAY AND MONDAY.
TODAY AND TONIGHT...FORECASTER CONFIDENCE: MODERATE
UPPER AIR ANALYSIS AND WATER VAPOR IMAGERY CLEARLY DEPICTED A STRONG
CLOSED LOW SPINNING OVER THE INTERMOUNTAIN WEST. SEVERAL SHORTWAVES
ARE EXPECTED TO MOVE THROUGH THE REGION THE NEXT DAY OR
SO...PROVIDING THE IMPETUS FOR SEVERAL ROUNDS OF THUNDERSTORM
DEVELOPMENT. INITIAL ROUND OF SHOWERS AND STORMS IS CURRENTLY MOVING
NEWD ACROSS THE CWA PER STOUT LLJ. NOTHING SEVERE WITH THIS
ACTIVITY...ALTHOUGH BRIEF HEAVY RAINFALL AND GUSTY WINDS ARE
POSSIBLE. IN FACT...SEVERAL OBS HAVE NOTED A WEAK "WAKE LOW"
ACROSS WESTERN SD.
IN THE WAKE OF THIS MORNING ACTIVITY...THERE IS STILL A FAIR AMOUNT
OF UNCERTAINTY FOR THE AFTERNOON...MAINLY WITH REGARDS TO
DESTABILIZATION. SEVERAL MODEL SOLUTIONS KEEP PERSISTENT CLOUDS AND
ELEVATED...WEAK THUNDERSTORMS IN THE AREA THROUGHOUT THE DAY. THIS
OUTCOME WOULD LIMIT ANY SEVERE THUNDERSTORM THREAT. OTHER SOLUTIONS
INDICATE A LULL IN PCPN...WITH AT LEAST PARTIAL SUNSHINE AND MORE
SIGNIFICANT INSTABILITY. AT THIS TIME...TRENDED THE FORECAST MORE
TOWARD THE LATER SOLUTION AND FEEL AT LEAST POCKETS OF MLCAPE OF 500-
1500 J/KG WILL DEVELOP IN CONCERT WITH WITH DEEP LAYER SHEAR VALUES
OF 30-40KTS BY 18Z. THUS...BELIEVE WE WILL SEE SCATTERED CONVECTION
RE-DEVELOP BETWEEN 18Z AND 21Z /PER LATEST HRRR SOLUTIONS/ WITH SOME
OF THESE STORMS BECOMING STRONG TO SEVERE. MAIN THREAT WOULD BE
HAIL AND DAMAGING WINDS...ALTHOUGH ANY OUTFLOW BOUNDARIES OR BACKED
SFC FLOW COULD ALSO PROVIDE ENOUGH SRH FOR AN ISOLATED TORNADO.
CORFIDI VECTORS ARE ALSO INDICATING RELATIVELY SLOW STORM
MOVEMENT...SO KEPT THE MENTION OF LOCALLY HEAVY RAINFALL AS WELL. A
STRONGER SHORTWAVE/PV ANOMALY WILL EJECT ACROSS THE NRN PLAINS
TONIGHT...LIKELY MAINTAINING OR INITIATING NEW TSTMS. SPC MAINTAINED
A SLIGHT RISK FOR THE ENTIRE AREA IN THE DAY 1 OUTLOOK...AND THIS
APPEARS REASONABLE.
SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE: MODERATE
AS MENTIONED PREVIOUSLY...THE TRACK OF THIS SYSTEM HAS IN FACT
SLOWED DOWN SUCH THAT A LINGERING SEVERE THREAT WILL CONTINUE ON
SUNDAY...MAINLY ALONG AND EAST OF THE JAMES RIVER VALLEY /IN THE
WARM SECTOR/. ALTHOUGH DEEP LAYER SHEAR WILL BE MARGINAL...SFC
VORTICITY INVOF OF THE SFC LOW COULD YIELD ANOTHER ROUND OF STRONG
TO SEVERE STORMS...AND POSSIBLE LANDSPOUT TYPE STORMS. DEFORMATION
ZONE PCPN IS EXPECTED NW OF THE SFC CYCLONE...WITH 00Z SUITE OF
MODELS INDICATING THE POTENTIAL FOR ADDITIONAL SIGNIFICANT
RAINFALL. FINALLY...IN THE WAKE OF THIS SYSTEM...A UNSEASONABLY
COLD AIRMASS WILL FILTER IN FROM THE NORTHWEST. 850MB/925MB TEMPS
ARE FORECAST TO FALL BELOW ZERO CELSIUS...WITH THE POSSIBILITY OF
A RAIN/SNOW MIX ACROSS N-CENTRAL SD. YES...I SAID A RAIN/SNOW MIX ON
MAY 16TH...UGH. PLENTY OF TIME TO FINE TUNE THIS FORECAST.
.LONG TERM...(MONDAY EVENING THROUGH FRIDAY)
ISSUED AT 435 AM CDT SAT MAY 16 2015
COOL CANADIAN HIGH PRESSURE WILL BE BUILDING SOUTH OVER THE REGION
MONDAY NIGHT INTO TUESDAY MORNING TO START OFF THE EXTENDED PERIOD.
LOOKING FOR RATHER COOL OVERNIGHT LOWS MONDAY NIGHT/TUESDAY MORNING
WITH READINGS AROUND FREEZING OR SLIGHTLY COOLER. ITS LOOKING LIKE
IT MAY NOT BE QUITE AS COLD AS PREVIOUSLY THOUGHT AS THERE IS STILL
A PRESSURE GRADIENT OVERHEAD BY 12Z TUESDAY WHICH WILL KEEP A BIT OF
A BREEZE GOING. NONETHELESS...THREAT FOR FROST/FREEZE CONDITIONS
STILL POSSIBLE TUESDAY MORNING AND STILL POSSIBLE FOR SFC HIGH TO BE
MORE OF AN INFLUENCE WITH WEAKER WINDS BEING THE CASE.
THE HIGH PRESSURE LINGERS OVER THE NORTHERN PLAINS DURING THE FIRST
PART OF THE EXTENDED...KEEPING COOL TEMPS OVER THE REGION THROUGH
MID WEEK. HIGHS ARE ONLY EXPECTED TO BE IN THE 50S TO LOW 60S WHICH
IS WELL BELOW NORMAL FOR THIS TIME OF YEAR. MODELS ALSO SHOWING SOME
SHORTWAVE ENERGY WORKING ACROSS THE CENTRAL/NORTHERN PLAINS TUESDAY
NIGHT THROUGH WEDNESDAY NIGHT...BUT IT WILL BE RUNNING INTO DRIER
AIR ASSOCIATED WITH THE HIGH. APPEARS BEST CHANCES FOR PRECIP WILL
BE OVER THE WEST/SOUTHWEST CWA.
MODELS SHOW WARMING TEMPS BY THE END OF THE UPCOMING WEEK WITH HIGHS
RETURNING CLOSER TO NORMAL BY FRIDAY. LOOKING WAY OUT...MODELS
TRYING TO SHOW ANOTHER SIGNIFICANT STORM SYSTEM POSSIBLY AFFECTING
THE REGION NEXT WEEKEND AS THE ACTIVE WEATHER PATTERN CONTINUES.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 435 AM CDT SAT MAY 16 2015
TWO WAVES OF SHOWERS AND THUNDERSTORMS ARE EXPECTED TO AFFECT ALL
TERMINALS TONIGHT AND AGAIN SATURDAY AFTERNOON. A STRONG WARM
FRONT/LLJ SURGING NORTH ALONG WITH AN UPPER LEVEL TROUGH/JET STREAK
WILL CONTINUE TO SPREAD THE FIRST ROUND OF SHOWERS AND THUNDERSTORMS
ACROSS ALL OF THE AREA INTO SATURDAY MORNING. EXPECT MAINLY MVFR
CEILINGS AND VISIBILITIES TONIGHT. THE RAIN AND STRATUS ARE EXPECTED
TO LIFT NORTH WHILE NEW SHOWER AND THUNDERSTORM DEVELOPMENT IS
EXPECTED SATURDAY AFTERNOON. SOME OF THESE COULD BE SEVERE.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...FOWLE
LONG TERM...TMT
AVIATION...TMT
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
340 AM CDT SAT MAY 16 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT SAT MAY 16 2015
TRICKY FORECAST FOR TODAY...WITH UNSETTLED WEATHER CONDITIONS
PERSISTING FOR MUCH OF THE DAY AND INTO TONIGHT. MAIN CONCERN IS HOW
THE ONGOING THUNDERSTORM ACTIVITY WILL IMPACT TEMPERATURES AND
SEVERE STORM CHANCES LATER ON TODAY.
SURFACE LOW PRESSURE HAS DEEPENED OVER THE BLACK HILLS EARLY THIS
MORNING AND IS SLOWLY DRIFTING NORTHWARD. SEVERAL BANDS OF
THUNDERSTORMS ARE LIFTING NORTHWARD WITH THE ADVANCING WARM FRONT
NEAR THE NEBRASKA AND SOUTH DAKOTA BORDER. THE MOST RECENT RUNS OF
THE HRRR SEEM TO HAVE A GOOD HANDLE ON THIS ACTIVITY...WHICH SHOULD
CONTINUE LIFTING NORTHEAST THROUGH AROUND MID MORNING...LOSING
INTENSITY AS THE NIGHT PROGRESSES. THINK THAT IN GENERAL THERE WILL
BE A LULL IN PRECIPITATION ACTIVITY AROUND LATE MORNING AND MIDDAY
BEFORE SCATTERED STORMS IGNITE AGAIN IN THE AFTERNOON AS THE
STRONGER WAVE PIVOTS INTO THE MISSOURI VALLEY. DEWPOINTS SHOULD
REACH THE LOW TO MID 60S ACROSS THE REGION BUT THE QUESTION IS HOW
MUCH DESTABILIZATION WILL BE POSSIBLE WITH CLOUD DEBRIS FROM MORNING
CONVECTION AND HOW THIS WILL IMPACT TEMPERATURES. IF SOME CLEARING
AND DESTABILIZATION OCCURS...SEVERE STORMS WILL BECOME POSSIBLE.
COULD SEE CAPE VALUES AS HIGH AS 1000 TO 1500 J/KG WITH DECENT
SHEAR. MAIN SEVERE THREATS WILL BE HAIL TO HALF DOLLAR SIZE AND WIND
GUSTS TO 65 MPH. TORNADIC THREAT IS VERY LOW WITH THE WARM FRONT
LIKELY NORTH OF THE FORECAST AREA...BUT COULD BE LOCALIZED IF THE
FRONT LAGS AT STORM INITIALIZATION. AGAIN...IF WEAKER
DESTABILIZATION OCCURS...THE SEVERE THREAT WILL ALSO DIMINISH FOR
THIS AFTERNOON AND EVENING.
EXPECT STORMS TO BECOME WIDESPREAD LATE AFTERNOON INTO THE
EVENING...WITH THE ARRIVAL OF THE JET MAX...FOLLOWED BY THE UPPER
LOW CENTER LIFTING INTO THE WESTERN FORECAST AREA OVERNIGHT. SEVERE
THREAT DIMINISHES LATE EVENING BUT WITH MULTIPLE CLUSTERS OF STORMS
LIFTING NORTH NORTHEAST THROUGH THE REGION...A GOOD SOAKING RAIN IS
EXPECTED FOR THE REGION. LOOKS LIKE AROUND A HALF INCH TO A LITTLE
OVER AN INCH IS POSSIBLE THROUGH TONIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 340 AM CDT SAT MAY 16 2015
STILL THINK THE NAM...LIKE A DAY AGO...IS A LITTLE TOO SLOW BRINGING
THE UPPER LOW NORTH ACROSS THE AREA. THE GFS AND EC LOOK BETTER BUT
THERE ARE DETAIL DIFFERENCES BETWEEN THESE MODELS ON PRECIPITATION
THREAT AS THE LOW MOVES NORTH. HAVE DECIDED TO KEEP A GENERAL
RAINFALL PATTERN FOCUSING ON OUR NORTHWEST EARLY WITH PRECIPITATION
THREAT AND AMOUNTS DECREASING SOUTH TO NORTH DURING THE DAY. THIS IS
NOT FAR FROM AN EC/GFS CONSENSUS. THE BIG QUESTION IS WILL THERE BE
A N/S BAND/LINE OF DECENT CONVECTION STILL GOING ON INTO THE MORNING
OVER THE EASTERN EDGE OF THE AREA...GOING WITH THE CONSENSUS THAT
MOST OF THIS WOULD BE DURING THE NIGHT AND BEGINNING TO MOVE NORTH
OF THE AREA.
AS FAR WEST AS THE LOW TRACK LOOKS...SURFACE WINDS WILL NOT BE GOING
WESTERLY UNTIL FAIRLY LATE IN THE DAY. TEMPERATURES SHOULD REACH THE
70S EAST TO THE 60S WEST.
THE SYSTEM SHOULD SLOWLY PULL OUT TO THE NORTHEAST SUNDAY NIGHT AND
HAVE A SHOWER THREAT DECREASING FROM SOUTHWEST TO NORTHEAST. IT DOES
LOOK WINDY RIGHT BEHIND THE LOW SUNDAY NIGHT. TEMPERATURES BY EARLY
MONDAY MORNING SHOULD DROP INTO THE UPPER 30S TO LOWER 40S.
MONDAY LOOKS COOL AND BREEZY TO WINDY. MODELS HINT AT A WEAK
SECONDARY SHORT WAVE DROPPING DOWN BEHIND THE MAIN SYSTEM. WITH COOL
AIR ALOFT A FEW LIGHT SHOWERS WOULD BE POSSIBLE AND LOW CLOUD COVER
SHOULD LINGER MUCH OF THE DAY ESPECIALLY NORTH. SUBSIDENCE BEHIND THE
LOW SHOULD COUNTER THIS AND MODEL INDICATIONS OF SOLID CLOUDS
LINGERING MOST OF THE DAY ARE PROBABLY OVERDONE. FOR THE SAME REASON
WILL LEAVE OUT ANY SHOWER OR SPRINKLE MENTION FOR NOW. DAYTIME HIGHS
WILL BE HELD TO THE MID 40S NORTHEAST TO THE MID 50S SOUTHWEST.
HIGH PRESSURE WILL BRING CLEARING BY MONDAY NIGHT AND A FAIRLY
BRIGHT DAY TUESDAY...THOUGH CLOUDS WILL BEGIN TO INCREASE FROM THE
SOUTHWEST BY LATE TUESDAY AS ONE IN A SERIES OF SHORT WAVES COMES UP
FROM THE SOUTHWESTERN USA TROUGH POSITION. THIS WILL BRING A THREAT
OF RAIN ESPECIALLY SOUTHWEST CENTERED ON WEDNESDAY...AND
TEMPERATURES WILL STILL BE COOL. AFTER A SHORT BREAK THURSDAY...A
CHANCE OF THUNDERSTORMS WILL DEVELOP AS THE WEEKEND APPROACHES AND A
STRONGER WAVE COMES UP. TEMPERATURES SHOULD BE WARMING A LITTLE BY
THE END OF THE WEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1107 PM CDT FRI MAY 15 2015
CURRENTLY...MVFR TO VFR CONTINUES TO DOMINATE THE SIOUX FALLS
FORECAST AREA. MOST OF THE MVFR IS BOTTLED UP ALONG AND NORTH OF I
90 WITH PRIMARILY VFR SOUTH OF I 90. OVERALL CONFIDENCE IS LOW
WITH THE 06Z SET OF TAFS WITH THE DETAILS. MODELS INCLUDING THE
LATEST NAM/GFS AND GEM REGIONAL CONTINUE TO SHOW A LOT OF LOW
LEVEL HUMIDITY BUILDING BACK IN BETWEEN 06Z AND 12Z TONIGHT BUT
HOW MUCH OF THIS IS BELIEVABLE REMAINS TO BE SEEN. TAKEN
LITERALLY...ALL OF THE TAF SITES WOULD GO IFR IF NOT LIFR BY 09Z
OR 10Z SATURDAY. WITH A RELATIVELY DRY EAST TO SOUTHEAST FLOW OF
AIR AM NOT BUYING THAT TOTALLY...AND OPTED TO HEDGE AND PUT IN
MVFR INSTEAD FOR NOW. THERE COULD BE ONE BAND OF RAIN MOVING
THROUGH SOUTHEAST SD AND EAST CENTRAL SD EARLY SATURDAY
MORNING...AND AGAIN ACROSS PARTS OF THE AREA LATE SATURDAY
AFTERNOON. FOR NOW...LEFT OUT THE MENTION OF THUNDERSTORMS AS
ELEVATED INSTABILITY IS ABUNDANT...BUT REMAINS TOO SKITTISH TO
MENTION AT A POINT LOCATION. AND A BULK OF THE ORGANIZED RAINFALL
WHEN THERE WILL BE THUNDERSTORMS FOR SURE DOES NOT OCCUR UNTIL IT
IS ON SIOUX CITY`S DOORSTEP TOWARD THE END OF THE TAF PERIOD. SO
AGAIN...LEFT IT OUT FOR NOW.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...
LONG TERM...
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1109 PM CDT FRI MAY 15 2015
.UPDATE...
ISSUED AT 914 PM CDT FRI MAY 15 2015
UPDATED EARLIER THIS EVENING TO REDUCE THE CHANCES FOR RAIN AND
STORMS THROUGH THE OVERNIGHT HOURS TO SLIGHT CHANCE OR NONE.
HOWEVER AM RELUNCTANT TO RADICALLY ALTER SHOWER AND THUNDERSTORM
CHANCES LATE TONIGHT AS THE HRRR AND NOW THE NEW NAM12 SHOW SOME
DEVELOPMENT ARCING THROUGH IN A NORTHWEST TO SOUTHEAST BAND. THIS
OCCURS LATE TONIGHT AND EARLY SATURDAY ALONG AN ELEVATED WARM
FRONT.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 414 PM CDT FRI MAY 15 2015
DEEP UPPER TROUGHING OVER THE SOUTHWESTERN UNITED STATES CONTINUES
TO POUR MOISTURE NORTHWARD INTO THE PLAINS THIS AFTERNOON.
HOWEVER...FOCUS FOR CONVECTION HAS BEEN SPLIT THROUGH MUCH OF THE
DAY...WITH MCV LIFTING NORTHWARD THROUGH WESTERN SD AND A SECONDARY
SHORTWAVE DRIVING CONVECTION IN THE MID/LOWER MISSOURI RIVER VALLEY.
OVERHEAD...WEAK ISENTROPIC ASSENT TIED NEAR THE 305K SFC CONTINUES
TO PRODUCE SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS.
HEADING INTO THE LATE AFTERNOON AND EVENING HOURS...MAIN FOCUS TURNS
TO WESTERN NE/SD AS UPPER JET BEGINS TO NOSE INTO THE PLAINS.
ALREADY A WELL DEVELOPED WARM FRONT STRETCHING ACROSS PORTIONS OF
NEBRASKA...BUT THE REINFORCING ELEVATED CONVECTION HAS KEPT THIS
BOUNDARY SW OF THE CWA THROUGH THE DAY. WITH 850:700 MB FLOW
BEGINNING TO BACK INTO THE WESTERN PLAINS ONGOING SHOWER ACTIVITY IN
THE LOCAL AREA MAY BEGIN TO WANE AS EVENING APPROACHES WITH
CONVECTION OVER NEBRASKA PANHANDLE TAKING OFF. WITH THE SFC WARM
FRONT TRYING TO REACH THE NE/SD LINE IN SOUTH CENTRAL SD...AN
ISOLATED STORM MAY STILL BE POSSIBLE EARLY THIS EVENING NEAR THE
MISSOURI RIVER.
THROUGH THE OVERNIGHT HOURS...LATEST HIGH RES GUIDANCE HINTS AT
SEVERAL CLUSTERS OF STORMS LIFTING NORTHEAST ACROSS NE/SD OVERNIGHT.
AS THE LEAD SHORTWAVE ENTERS THE PLAINS LATE THIS EVENING...WE MAY
BEGIN TO SEE THE LLJ VEER SOUTHWESTERLY WHICH COULD REIGNITE
ADDITIONAL ELEVATED CONVECTION FURTHER SOUTHEAST THROUGH CENTRAL
NEBRASKA AND SOUTH CENTRAL SD ALONG ELEVATED BOUNDARY LIFTING
NORTHEAST. INSTABILITY WOULD BE WANING AT THIS POINT...BUT COULD
BE DEALING WITH MARGINAL HAIL OR PERHAPS BRIEF WIND GUSTS GIVEN
PARALLEL ORIENTATION OF LOW LVL FLOW. THIS STRONGER STORM RISK WOULD
MAINLY BE WEST OF THE JAMES RIVER INTO THE EARLY MORNING
HOURS...HOWEVER THE RISK OF CONVECTION COULD SPREAD ALL THE WAY
EASTWARD INTO WESTERN MN.
FOR SATURDAY...A VERY TRICKY FORECAST REMAINS. DEEP MERIDIONAL FLOW
IS EXPECTED TO FURTHER ENHANCE MOISTURE OVERNIGHT INTO THE
AREA...WITH LLJ KEEPING ELEVATED CONVECTION LINGERING OVER THE CWA
INTO EARLY SATURDAY MORNING. A MUCH STRONGER WAVE WILL PIVOT INTO
THE PLAINS SATURDAY AFTERNOON. THE BIGGEST QUESTION FOR
SATURDAY...GIVEN THE DEEP MERIDIONAL FLOW...IS THE DEGREE OF CLOUD
COVER AND INSTABILITY THAT CAN GROW THROUGH THE AFTERNOON. THERE
ARE SOME HINTS THAT LINGERING CLOUD COVER AND ELEVATED SHOWERS MAY
WORK TO REINFORCE THE EML IN THE AFTERNOON...WITH MODELS HINTING AT
A WEAK SHORTWAVE RACING NORTHWARD AND THROUGH THE AREA BY MID-DAY
SATURDAY. HOWEVER...THE BEST CHANCE FOR ANY MORE SUBSTANTIAL GROWTH
IN SFC BASED INSTABILITY WILL BE ALONG A NORTH-SOUTH ORIENTATED
SFC BOUNDARY ACROSS WEST CENTRAL SD/NE. THAT SAID...CANNOT RULE
OUT A FEW STRONG STORM CLUSTERS...MAINLY BOWING SEGMENTS FURTHER
EAST...ESPECIALLY IF STRONGER POCKETS OF INSTABILITY CAN GROW
GIVEN THE UNIDIRECTIONAL FLOW AND DECENT SPEED SHEAR ALOFT.
AGAIN...VERY CONDITIONAL AND UNCERTAIN.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 414 PM CDT FRI MAY 15 2015
THE CHANCE FOR THUNDERSTORMS WILL INCREASE RAPIDLY SATURDAY
EVENING AS A STRONG SHORT WAVE TROUGH AND JET STREAK MOVE
NORTHWARD INTO SOUTH DAKOTA. EXPECTED SCENARIO AT THIS TIME IS
THAT THUNDERSTORM COVERAGE WILL SLOWLY INCREASE THROUGH THE
EVENING AS WAVE APPROACHES WITH A CLUSTER OF SHOWERS AND
THUNDERSTORMS MOVING INTO THE MISSOURI VALLEY AROUND SUNSET AND
REACHING I90 BEFORE MIDNIGHT. WITH ALMOST NO CAPPING
INVERSION...THESE SHOWERS AND STORMS WILL CONTINUE DEVELOP AND MOVE
NORTHEAST THROUGH THE NIGHT. WITH WIDESPREAD STORMS...SEVERE
WEATHER IS UNLIKELY EXCEPT AHEAD OF THE MAIN CLUSTER OF STORMS IN
THE EVENING...ASSUMING ENOUGH INSTABILITY IS PRESENT TO PRODUCE A
STRONG ENOUGH UPDRAFT TO SUPPORT MARGINALLY SEVERE HAIL. AS NOTED
ABOVE...THIS THREAT IS VERY CONDITIONAL AND UNCERTAIN AS CAPES BY
EVENING WILL LIKELY BE AT OR BELOW 1000 J/KG. INSTEAD EXPECTING A
WIDESPREAD 0.5 TO 1.0 INCH OF RAIN SATURDAY NIGHT. LOCAL AMOUNTS
COULD EXCEED 1.5 INCHES IN PORTIONS OF THE AREA. WITH THE CLOUDS
AND PRECIPITATION LOWS WILL BE AROUND 60.
ON SUNDAY...SHOWERS AND STORMS WILL LINGER INTO THE
MORNING...ESPECIALLY NORTH OF I90. THEN A DRY SLOT WILL MOVE OVER
THE AREA WHICH SHOULD BRING A RESPITE TO THE PRECIPITATION TO MOST
AREA. A DRY LINE IS THEN EXPECTED TO MOVE ACROSS THE AREA ON
SUNDAY MORNING. AT THIS POINT...HAVE LOW POPS WITH THE DRY LINE
AS UPPER FORCING FOR ASCENT IS MINIMAL AND ATMOSPHERE WILL BE
FAIRLY STABLE FOLLOWING THE OVERNIGHT CONVECTION. A COLD FRONT
WILL MOVE ACROSS SUNDAY AFTERNOON. WITH LIMITED MOISTURE...
PRECIPITATION WILL NOT BE AS WIDESPREAD AND IS EXPECTED TO BE
FOCUSED CLOSER TO THE UPPER LOW MOVING ACROSS CENTRAL SD AND
EASTERN ND. SO HAVE THE HIGHEST POPS NORTH OF INTERSTATE 90. WHILE
THUNDER IS POSSIBLE WITH ANY STORMS...WITH THE LIMITED INSTABILITY
AND MOISTURE...HAVE PRIMARILY RAIN SHOWERS WITH A LOWER
PROBABILITY OF THUNDER. HIGHS WILL BE IN THE MID 70S WHERE THE
COLD FRONT WILL MOVE THROUGH IN THE LATE AFTERNOON...WITH MID 60S
IN CENTRAL SOUTH DAKOTA WHERE THERE WILL BE MORE CLOUDS AND MUCH
EARLY COLD FRONTAL PASSAGE.
FROM SUNDAY AFTERNOON INTO MONDAY EVENING...THE FOCUS WILL SHIFT
FOR RAIN TO WIND AND COLD. ONCE THE COLD FRONT MOVES THROUGH
SUNDAY AFTERNOON...NORTHWEST WIND WILL REALLY INCREASE WITH GUSTS
WELL ABOVE 30 MPH BY SUNDAY EVENING. WINDS WILL DROP LITTLE ON
SUNDAY NIGHT AND THEN PICK BACK UP WITH SUSTAINED WINDS OVER 20
MPH ON MONDAY. TEMPERATURES WILL FALL FAIRLY QUICKLY SUNDAY NIGHT
WITH LOWS IN THE 30S TO LOW 40S. ON MONDAY...THERE WILL BE A LOT
OF LOW LEVEL MOISTURE AROUND SO EVEN IF THERE IS SOME BREAKS IN
CLOUDS MONDAY MORNING...WITH 850 MB TEMPS BELOW ZERO...SUNSHINE
WILL BE SELF DESTRUCTIVE AND SKIES IN MOST AREA WILL BECOME CLOUDY
BY LATE MORNING. MOST PLACES WILL LIKELY REACH HIGHS IN THE 40S TO
MID 50S BY EARLY AFTERNOON AND THEN HOLDING STEADY. AT THIS POINT
THE GFS BUFR SOUNDINGS SHOW A VERY SHALLOW UNSTABLE LAYER SO NOT
EXPECTING SHOWERS TO DEVELOP BUT WILL NEED TO MONITOR THE
POTENTIAL AS NAM/ECMWF SOUNDINGS WOULD SUPPORT A MIX OF GRAUPAL
AND RAIN IN PORTIONS OF SW MN AND EAST CENTRAL SD.
IN THE LONGER RANGE...MONDAY NIGHT THROUGH FRIDAY...BELOW NORMAL
TEMPERATURES ARE EXPECTED TO CONTINUE. THE MODELS HAVE A GENERAL
AGREEMENT WITH A LONG WAVE TROUGH OVER THE AREA THROUGH THE WEEK.
THE BEST CHANCE OF RAIN WILL BE ON LATE TUESDAY NIGHT AND
WEDNESDAY BUT THERE IS SOME QUESTION HOW FAR EAST THE RAIN WILL
GET AS EASTERLY FLOW FROM HIGH PRESSURE WILL ACT TO LIMIT MOISTURE
FLOW INTO THE AREA AND MAY PREVENT RAIN FROM REACHING SW MN AND
PORTIONS OF NW IA. TEMPERATURES THROUGH WEDNESDAY WILL BE IN THE
50S WITH UNSEASONABLY COLD AIR BOTH DAYS AND CLOUDS AND RAIN ON
WEDNESDAY. A GRADUAL WARM UP WILL BEGIN ON THURSDAY AND CONTINUE
INTO FRIDAY ALTHOUGH IT IS MOST LIKELY HIGHS WILL REMAIN IN THE
60S. A STRONGER WAVE WILL ALSO APPROACH LATER FRIDAY WHICH MAY
BRING A CHANCE OF THUNDERSTORMS BY AFTERNOON. HOWEVER...THE BETTER
CHANCE WILL BE INTO MEMORIAL DAY WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1107 PM CDT FRI MAY 15 2015
CURRENTLY...MVFR TO VFR CONTINUES TO DOMINATE THE SIOUX FALLS
FORECAST AREA. MOST OF THE MVFR IS BOTTLED UP ALONG AND NORTH OF I
90 WITH PRIMARILY VFR SOUTH OF I 90. OVERALL CONFIDENCE IS LOW
WITH THE 06Z SET OF TAFS WITH THE DETAILS. MODELS INCLUDING THE
LATEST NAM/GFS AND GEM REGIONAL CONTINUE TO SHOW A LOT OF LOW
LEVEL HUMIDITY BUILDING BACK IN BETWEEN 06Z AND 12Z TONIGHT BUT
HOW MUCH OF THIS IS BELIEVABLE REMAINS TO BE SEEN. TAKEN
LITERALLY...ALL OF THE TAF SITES WOULD GO IFR IF NOT LIFR BY 09Z
OR 10Z SATURDAY. WITH A RELATIVELY DRY EAST TO SOUTHEAST FLOW OF
AIR AM NOT BUYING THAT TOTALLY...AND OPTED TO HEDGE AND PUT IN
MVFR INSTEAD FOR NOW. THERE COULD BE ONE BAND OF RAIN MOVING
THROUGH SOUTHEAST SD AND EAST CENTRAL SD EARLY SATURDAY
MORNING...AND AGAIN ACROSS PARTS OF THE AREA LATE SATURDAY
AFTERNOON. FOR NOW...LEFT OUT THE MENTION OF THUNDERSTORMS AS
ELEVATED INSTABILITY IS ABUNDANT...BUT REMAINS TOO SKITTISH TO
MENTION AT A POINT LOCATION. AND A BULK OF THE ORGANIZED RAINFALL
WHEN THERE WILL BE THUNDERSTORMS FOR SURE DOES NOT OCCUR UNTIL IT
IS ON SIOUX CITY`S DOORSTEP TOWARD THE END OF THE TAF PERIOD. SO
AGAIN...LEFT IT OUT FOR NOW.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
UPDATE...MJ
SHORT TERM...DUX
LONG TERM...SCHUMACHER
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
856 PM CDT SUN MAY 17 2015
.DISCUSSION...WATER VAPOR SATELLITE/WSR-88D VAD WIND PROFILES
INDICATE A MESOSCALE CONVECTIVE VORTEX /MCV/ OVER LOUISIANA. THIS
MCV ALONG WITH A SUBTLE 700 MB SHORTWAVE TROUGH OVER THE LOWER
MISSISSIPPI HAD RESULTED IN ADDITIONAL SHOWERS AND THUNDERSTORMS
DEVELOPING ACROSS THE MID SOUTH THIS EVENING...MAINLY WEST OF THE
MISSISSIPPI RIVER. AS OF 8 PM CDT...TEMPERATURES ACROSS THE
MID SOUTH ARE IN THE LOWER 70S AT MOST LOCATIONS.
LATEST HRRR ALONG WITH THE 00Z WRF INDICATE POTENTIAL FOR RE-
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS THE MID SOUTH
OVERNIGHT. WILL MAKE SOME ADJUSTMENTS TO POPS AND ALL OTHER
ELEMENTS AS NEEDED FOR THE REMAINDER OF THE NIGHT.
UPDATED GRIDS WILL BE AVAILABLE SHORTLY.
CJC
&&
.PREV DISCUSSION... /ISSUED 639 PM CDT SUN MAY 17 2015/
UPDATE...AVIATION DISCUSSION.
PREV DISCUSSION... /ISSUED 304 PM CDT SUN MAY 17 2015/
THE MIDSOUTH REMAINS STUCK UNDERNEATH SOUTHWEST FLOW ALOFT. THE
SOUTHWEST FLOW ALOFT HAS BROUGHT THIS WET PATTERN TO THE REGION AS
THE COMBINATION OF SHORTWAVES MOVING THROUGH THE FLOW AND AN
ABUNDANCE OF MOISTURE FROM THE GULF OF MEXICO HAS PRODUCED ROUND
AFTER ROUND OF SHOWERS AND THUNDERSTORMS.
LOOKING AT LATEST RADAR IMAGES...MOST OF THE SHOWER AND
THUNDERSTORM ACTIVITY HAS NOW PUSHED EAST OF THE MISSISSIPPI
RIVER. MOST OF THIS CONVECTION WILL LIKELY PUSH EAST OF THE CWA BY
7 PM. HOWEVER...LATEST HRRR SHOWS REDEVELOPMENT OCCURRING OVER
NORTHEAST ARKANSAS BY THAT TIME. THE CORRIDOR FROM NORTHEAST
ARKANSAS AND THE MISSOURI BOOTHEEL MAY SEE MOST OF THE CONVECTION
DURING THE LATE EVENING INTO THE OVERNIGHT HOURS BEFORE IT SHIFTS
SOUTHWARD ON MONDAY. HAVE ADJUSTED POPS ACCORDINGLY. IN
ADDITION...SINCE THERE ARE PORTIONS OF NORTHEAST MISSISSIPPI THAT
HAS SEEN SEVERAL ROUNDS OF HEAVY SHOWERS TODAY...WILL GO AHEAD AND
EXPAND THE FLASH FLOOD WATCH SOUTHWARD TO COVER THE ENTIRE CWA
THROUGH MONDAY.
MONDAY WILL BE ANOTHER RAINY DAY FOR THE MIDSOUTH WITH OFF AND ON
PERIODS OF HEAVY SHOWERS AND THUNDERSTORMS. EXPECT HIGHS IN THE
UPPER 70S TO LOWER 80S.
THE COLD FRONT WILL FINALLY BEGIN TO PUSH INTO THE AREA MONDAY
NIGHT INTO TUESDAY. MODELS ARE COMING INTO TO CLOSER AGREEMENT
THAT THE FRONT WILL STALL OUT JUST SOUTH OF THE CWA AND BEGIN
LIFTING BACK NORTHWARD AS A WARM FRONT LATE TUESDAY NIGHT INTO
WEDNESDAY. THIS WILL KEEP SMALL CHANCES FOR SHOWERS AND
THUNDERSTORMS IN THE FORECAST FOR PORTIONS OF EAST-CENTRAL
ARKANSAS AND NORTH MISSISSIPPI WHILE GIVING THE REST OF THE CWA
ONLY A BRIEF REPRIEVE ON TUESDAY NIGHT.
BY WEDNESDAY...THE ENTIRE MIDSOUTH WILL SEE CHANCES FOR SHOWERS
AND THUNDERSTORMS AGAIN AS A WEAK SHORTWAVE MOVES ACROSS THE CWA.
BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS WILL COME WEDNESDAY
NIGHT INTO THURSDAY AS THE FRONT MOVES BACK THROUGH THE AREA AS A
COLD FRONT.
HIGH PRESSURE WILL BUILD INTO THE AREA THURSDAY NIGHT THROUGH
SATURDAY. NO PRECIPITATION IS EXPECTED AS A RESULT. HIGHS WILL BE
IN THE MID 70S TO LOWER 80S. LOWS WILL BE IN THE MID 50S TO LOWER
60S.
LOOKS LIKE THE MIDSOUTH COULD BE UNDERNEATH SOUTHWEST FLOW ALOFT
AGAIN BY SATURDAY NIGHT CONTINUING INTO EARLY NEXT WEEK. THIS
COULD BRING ANOTHER EXTENDED WET PERIOD TO THE REGION.
KRM
&&
.AVIATION...
00Z TAFS
MORE OF THE SAME OVER THE NEXT 24 HOURS....ALTHOUGH THIS LOOKS
LIKE THE END OF SEVERAL DAYS OF DEALING WITH STORMS. PERIODS OF
THUNDERSTORMS WILL RESULT IN BRIEF IFR VIS AND VARIABLE GUSTY
WINDS.
A LINE OF THUNDERSTORMS IS DEVELOPING OVER EAST ARKANSAS AND COULD
IMPACT JBR BY 1-2Z. DID NOT INCLUDE TS AT MEM...BUT THAT MAY NEED
TO BE ADDED BASED ON RADAR TRENDS OVER THE NEXT COUPLE OF HOURS.
ARRIVAL WOULD LIKELY BE 3-4Z.
SHORT RANGE MODELS INDICATE ANOTHER YET ROUND OF TSRAS WILL FIRE
UP AFTER MIDNIGHT...SHIFTING ACROSS JBR...MEM...AND MKL PRIOR TO
SUNRISE. MODELS DISAGREE ON HOW WIDESPREAD LOW CLOUDS LATER
TONIGHT AND MON MORNING. BEST CHANCES APPEAR TO BE AT KTUP AND
PLACED A MVFR CIG THERE MONDAY MORNING OTRW WILL GO WITH
OPTIMISTIC FORECAST. ANOTHER ROUND OF DAYTIME HEATING DRIVEN
STORMS IS EXPECTED TOMORROW. WILL CARRY TEMPO TSRA AT ALL SIDES
FOR MOST OF THE AFTERNOON.
SOUTH WINDS 10-12 KTS WITH HIGHER GUSTS THIS AFTN...8-10 KTS
TONIGHT. WINDS SHOULD BEGIN TO SHIFT MORE WESTERLY OR
NORTHWESTERLY BY SUNSET TOMORROW...AND PRECIPITATION SHOULD COME
TO AN END.
30
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR CLAY-CRAIGHEAD-
CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI-
PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.
MO...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR DUNKLIN-PEMISCOT.
MS...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR ALCORN-BENTON MS-
CALHOUN-CHICKASAW-COAHOMA-DESOTO-ITAWAMBA-LAFAYETTE-LEE MS-
MARSHALL-MONROE-PANOLA-PONTOTOC-PRENTISS-QUITMAN-
TALLAHATCHIE-TATE-TIPPAH-TISHOMINGO-TUNICA-UNION-YALOBUSHA.
TN...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR BENTON TN-CARROLL-
CHESTER-CROCKETT-DECATUR-DYER-FAYETTE-GIBSON-HARDEMAN-
HARDIN-HAYWOOD-HENDERSON-HENRY-LAKE-LAUDERDALE-MADISON-
MCNAIRY-OBION-SHELBY-TIPTON-WEAKLEY.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
311 PM CDT SAT MAY 16 2015
.DISCUSSION...
POPCORN TYPE SHOWERS AND THUNDERSTORMS ARE OCCURRING ACROSS THE
MIDSOUTH AND SURROUNDING AREAS. LATEST HRRR SHOWS THIS ACTIVITY
CONTINUING THROUGH AROUND 7-8 PM. THEREAFTER...ACTIVITY WILL
DISSIPATE FROM THE LOSS OF DAYTIME HEATING. EXPECT THE REMAINDER
OF THE NIGHT TO BE TRANQUIL. WILL LEAVE 30 POPS IN CASE A STRAY
SHOWER OR THUNDERSTORM DEVELOPS. LOWS WILL BE IN THE MID TO UPPER
60S.
A SEVERE LINE OF SHOWERS AND THUNDERSTORMS IS EXPECTED TO DEVELOP
THIS EVENING ACROSS OKLAHOMA...KANSAS...AND TEXAS. MODELS HAVE
BEEN PRETTY CONSISTENT WITH BRINGING THE REMNANTS OF THIS LINE
INTO EASTERN ARKANSAS AROUND SUNRISE. STILL EXPECT THE LINE TO BE
IN THE DYING PHASES AS IT MOVES IN. THE LINE WILL FALL APART AS IT
REACHES THE MS RIVER DURING THE MORNING. HOWEVER...REDEVELOPMENT
ALONG LEFTOVER BOUNDARIES WILL BE POSSIBLE ALONG AND EAST OF THE
MISSISSIPPI RIVER FROM MID-MORNING ON SUNDAY INTO THE AFTERNOON
HOURS.
EXPECT SHOWER AND THUNDERSTORM ACTIVITY TO DIE OUT AGAIN BY 7PM
SUNDAY EVENING. NEW DEVELOPMENT MAY OCCUR ALONG AND WEST OF THE
MISSISSIPPI RIVER DURING THE LATE EVENING TO OVERNIGHT HOURS AS A
SHORTWAVE MOVES INTO THE REGION. THIS ACTIVITY WILL BLOSSOM OVER
THE CWA INTO MONDAY.
THE COLD FRONT IS STILL EXPECTED TO MOVE INTO THE AREA MONDAY
NIGHT INTO TUESDAY. SCATTERED CHANCES FOR SHOWERS AND
THUNDERSTORMS WILL CONTINUE ALONG AND AHEAD OF THE FRONT.
THE ECMWF AND GFS DIFFER ON HOW FAR SOUTH THE FRONT WILL PROGRESS.
IF THE ECMWF IS CORRECT...TUESDAY NIGHT MAY BE THE ONLY DRY PERIOD
BEFORE THE FRONT MOVES BACK NORTH AS A WARM FRONT. CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL OCCUR ALONG AND AHEAD OF THE WARM
FRONT. THE FRONT WILL RETURN SOUTHWARD AS A COLD FRONT ON
THURSDAY. BEST CHANCES FOR SHOWERS AND THUNDERSTORMS WILL LIKELY OCCUR
ON THURSDAY.
HIGH PRESSURE WILL THEN BUILD INTO THE AREA ON FRIDAY.
&&
.AVIATION...
18Z TAFS
WIDESPREAD MVFR CIGS ACROSS THE MIDSOUTH THIS MORNING WILL
GRADUALLY LIFT TO VFR THIS AFTERNOON. SCATTERED SHRA AND TSRAS
EXPECTED ACROSS THE REGION AND WILL CONTINUE VCTS AT ALL TERMINALS
THROUGH EARLY EVENING. COVERAGE WILL DIMINISH WILL LOSS OF
HEATING THIS EVENING. QUIET OVERNIGHT THEN LOW CLOUDS SHOULD
REDEVELOP LATER TONIGHT INTO EARLY SUNDAY...ESPECIALLY AT KJBR AND
KTUP. A WEAKENING LINE OF SHRAS AND TSRAS WILL BE PUSHING INTO THE
MIDSOUTH SUNDAY MORNING.
SOUTH WINDS AROUND 10KTS THROUGH THE PERIOD WITH OCNL HIGHER GUSTS
THIS AFTERNOON AT MEM AND KJBR.
SJM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
102 PM CDT SAT MAY 16 2015
.DISCUSSION...
UPDATED FOR 18Z AVIATION DISCUSSION
&&
.PREV DISCUSSION... /ISSUED 1049 AM CDT SAT MAY 16 2015/
UPDATE...
AN AREA OF SHOWERS CONTINUE TO MOVE NORTH OVER PORTIONS OF WEST
TENNESSEE...NORTHEAST ARKANSAS...AND THE MISSOURI BOOTHEEL. THIS
AREA SHOULD MOVE INTO KENTUCKY AND MISSOURI BETWEEN 12-1 PM.
MEANWHILE...DRY CONDITIONS ARE CURRENTLY OCCURRING OVER NORTH
MISSISSIPPI. THE LATEST HRRR SHOWS ADDITIONAL DEVELOPMENT
OCCURRING ACROSS SOUTHERN MISSISSIPPI THAT WILL MOVE INTO NORTH
MISSISSIPPI AROUND 2 PM. THE CONVECTION WILL EVENTUALLY SPREAD
INTO THE REST OF THE MIDSOUTH BETWEEN 3-5 PM. FORECAST LOOKS
GOOD...NO UPDATES ARE EXPECTED.
KRM
DISCUSSION... /ISSUED 430 AM CDT SAT MAY 16 2015/
A WET DAY IS IN STORE FOR THE MIDSOUTH TODAY...FINALLY SEEMS MORE
LIKE MAY ACROSS THE MIDSOUTH THAN WHAT WE HAVE EXPERIENCED THROUGH
MUCH OF THE FIRST HALF OF THE MONTH. AREAS OF RAIN AND A FEW
THUNDERSTORMS WERE ALREADY OCCURRING ACROSS THE MIDSOUTH EARLY THIS
MORNING. THE WET PATTERN WILL CONTINUE INTO MONDAY AND WILL NEED TO
MONITOR FOR THE POSSIBILITY OF FLOODING / FLASH FLOODING AS RAINFALL
AMOUNTS INCREASE OVER TIME THROUGH THE WEEKEND INTO MONDAY.
A LARGE UPPER LEVEL LOW WAS LOCATED OVER THE WESTERN UNITED
STATES WITH AN UPPER LEVEL RIDGE ALONG THE SOUTHEAST COAST. A
SOUTHERLY WIND FLOW BETWEEN THESE TWO SYSTEMS WAS PUSHING ABUNDANT
MOISTURE INTO THE MIDSOUTH FROM THE GULF OF MEXICO. AN UPPER LEVEL
SHORT WAVE WAS LOCATED OVER EAST TX AND WILL MOVE NORTHEASTWARD
THROUGH THE MIDSOUTH TODAY. OCCASIONAL SHOWERS AND SCATTERED
THUNDERSTORMS ARE EXPECTED ACROSS THE REGION TODAY. PRECIPITABLE
WATER VALUES WILL BE BETWEEN 1.8 AND 2.0 INCHES WITH SURFACE DEW
POINTS IN THE MIDDLE 60S TO NEAR 70 DEGREES. AS A RESULT...LOCALLY
HEAVY RAINFALL MAY RESULT IN FLOODING IN SOME LOCATIONS TODAY...BUT
NOT CONFIDENT ENOUGH THAT WILL BE WIDESPREAD ENOUGH FOR A FLASH FLOOD
WATCH ATTM. DID MENTION THE THREAT OF LOCALLY HEAVY RAINFALL
AND FLOODING IN THE HAZARDOUS WEATHER OUTLOOK FOR TODAY. INSTABILITY
LOOKS TO BE A LITTLE LESS THAN YESTERDAY WITH MORE WIDESPREAD RAIN
AND CLOUDS.
FOR TONIGHT...AN UPPER LEVEL TROUGH MOVES INTO THE CENTRAL PLAINS
WITH AN ASSOCIATED COLD FRONT STRETCHING FROM KS INTO TX. ORGANIZED
CONVECTION IS EXPECTED TO DEVELOP AHEAD OF THIS FRONT THROUGH THE
PLAINS PERHAPS APPROACHING NORTHEAST ARKANSAS LATE TONIGHT...ALTHOUGH
INSTABILITY DECREASING BY THAT TIME. WEAK UPPER LEVEL DISTURBANCES
EMBEDDED IN SOUTHWEST FLOW ALOFT WILL CONTINUE THE THREAT FOR
SCATTERED SHOWERS AND THUNDERSTORMS TONIGHT ACROSS THE MIDSOUTH.
SUNDAY...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR
WITH LOCALLY HEAVY RAINFALL A CONTINUING THREAT. THE UPPER LEVEL
TROUGH WILL PUSH TO THE NORTHEAST THROUGH THE CENTRAL PLAINS WITH
THE ASSOCIATED COLD FRONT REMAINING TO OUR WEST AND NORTH. THE
GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE TO OUR NORTH. 0-6
KM BULK SHEAR VALUES ARE ONLY MARGINAL FOR ORGANIZED SHEAR WEATHER
NEAR EXTREME NORTHEAST ARKANSAS AND THE MO BOOTHEEL. HOWEVER...
WIND FIELDS WILL BE STRONGER ACROSS THE MIDSOUTH SUNDAY AS THE UPPER
LEVEL TROUGH MOVES TO OUR NORTH. THIS WILL ALLOW WARMER SURFACE
TEMPERATURES TO PUSH INTO THE MIDSOUTH CAUSING GREATER INSTABILITY
AND THE POSSIBILITY A FEW STRONG TO SEVERE THUNDERSTORMS. IF ANY
SEVERE THUNDERSTORMS DO DEVELOP...DAMAGING WIND AND LARGE HAIL
WOULD BE THE GREATEST SEVERE WEATHER THREATS.
A COLD FRONT WILL SAG INTO THE MIDSOUTH FROM THE NORTH MONDAY AS THE
UPPER LEVEL RIDGE ALONG THE SOUTHEAST COAST WEAKENS SOME WITH
LOWERING UPPER LEVEL HEIGHTS ACROSS THE MIDSOUTH. WILL ONCE AGAIN
NEED TO MONITOR FOR HEAVY RAINFALL AND FLOODING / FLASH FLOODING.
THE COLD FRONT WILL GRADUALLY PUSH THROUGH THE MIDSOUTH MONDAY NIGHT
AND TUESDAY WITH DECREASING CHANCES FOR RAIN FROM THE NORTH.
TEMPERATURES WILL BE A LITTLE COOLER WITH PASSAGE OF THE COLD FRONT.
FOR THE REMAINDER OF THE WORK WEEK...THE ECMWF AND GFS ARE NOT IN
VERY GOOD AGREEMENT ON HOW FAR SOUTH THE COLD FRONT PUSHES AND HOW
QUICKLY IT PUSHES BACK NORTH. NEVERTHELESS...THE MODELS DO INDICATE
A CHANCE OF SHOWERS...PERHAPS THUNDERSTORMS...WILL MOVE BACK INTO
THE REGION FROM THE WEST. THE ECMWF IS FASTER BRINGING THE THREAT
OF SHOWERS AND THUNDERSTORMS BACK INTO THE REGION AS QUICKLY AS
WEDNESDAY.
JCL
&&
.AVIATION...
18Z TAFS
WIDESPREAD MVFR CIGS ACROSS THE MIDSOUTH THIS MORNING WILL
GRADUALLY LIFT TO VFR THIS AFTERNOON. SCATTERED SHRA AND TSRAS
EXPECTED ACROSS THE REGION AND WILL CONTINUE VCTS AT ALL TERMINALS
THROUGH EARLY EVENING. COVERAGE WILL DIMINISH WILL LOSS OF
HEATING THIS EVENING. QUIET OVERNIGHT THEN LOW CLOUDS SHOULD
REDEVELOP LATER TONIGHT INTO EARLY SUNDAY...ESPECIALLY AT KJBR AND
KTUP. A WEAKENING LINE OF SHRAS AND TSRAS WILL BE PUSHING INTO THE
MIDSOUTH SUNDAY MORNING.
SOUTH WINDS AROUND 10KTS THROUGH THE PERIOD WITH OCNL HIGHER GUSTS
THIS AFTERNOON AT MEM AND KJBR.
SJM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1257 PM CDT SAT MAY 16 2015
.UPDATE...
18Z TAF DISCUSSION.
&&
.AVIATION...
NUMEROUS -SHRA CONTINUE NEAR ALL AIRPORTS THIS AFTERNOON ALTHOUGH
ACTIVITY IS BECOMING MORE SCATTERED WITH TIME. WILL HAVE -SHRA
UNTIL 21-00Z AT TERMINALS WITH VCSH AFTERWARDS...BUT ADDITIONAL
-SHRA AT CSV AFTER 03Z AS HRRR SHOWS ANOTHER ROUND MOVING THROUGH.
WILL LEAVE OUT MENTION OF TS DUE TO LIMITED INSTABILITY IN THE
VERY MOIST AIRMASS. IFR/MVFR CIGS/VIS WILL PREVAIL THROUGH 00Z
WITH MVFR/VFR AFTER THAT TIME. LIGHT SOUTH WINDS ANTICIPATED
THROUGH THE TAF PERIOD.
SHAMBURGER
&&
.PREV DISCUSSION... /ISSUED 927 AM CDT SAT MAY 16 2015/
UPDATE...MADE SOME MINOR ADJUSTMENTS TO POPS AND HOURLY
TRENDS...OTHERWISE FORECAST ON TRACK. SHOWERS COVERED MUCH OF MID
TN THIS MORNING...AND THIS WILL CONTINUE THROUGH MIDDAY. DURING
THE AFTERNOON...THE COVERAGE OF SHOWERS WILL DECREASE SLIGHTLY FROM
SOUTHWEST TO NORTHEAST...ALLOWING FOR SOME BREAKS IN THE RAINFALL.
THIS WILL ALSO ALLOW A LITTLE MORE DESTABILIZATION...AND A BETTER
CHANCE FOR ISOLATED THUNDERSTORMS. NO SEVERE WX IS EXPECTED.
RAINFALL AMOUNTS TODAY WILL RANGE MOSTLY FROM ONE QUARTER TO THREE
QUARTERS OF AN INCH. THE EXTENSIVE SHOWERS/CLOUDS WILL LIMIT HIGH
TEMPS TO THE 70S FOR MOST AREAS.
13
PREV DISCUSSION... /ISSUED 627 AM CDT SAT MAY 16 2015/
UPDATE...FOR 12Z AVIATION.
AVIATION...12Z TAF DISCUSSION.
SHOWERS ARE MOVING NORTHWARD INTO MIDDLE TN AT ISSUANCE AND SHOULD
BEGIN AFFECTING ALL 3 TERMINALS OVER THE NEXT COUPLE OF HOURS.
FLIGHT CATEGORIES WILL WAVER BETWEEN VFR AND MVFR FOR THE MOST
PART AS THESE LIGHT TO MODERATE RAIN MOVE THROUGH THE STATE. SOME
TS MAY BE MIXED IN BUT JUST COVERED WITH VCTS ATTM. ACTIVITY WILL
CONTINUE ON AND OFF THROUGHOUT THE DAY AND INTO THE EVENING HOURS.
SOME IFR CIGS/VIS CAN BE EXPECTED WITH ANY HEAVIER RAINS AND/OR TS.
SOUTHERLY WINDS WILL BE 8-12 KTS THROUGHOUT THE DAY WITH A GUST TO
20 OR 25 KTS POSSIBLE IN AND AROUND ANY TS THAT MAY AFFECT A
TERMINAL.
UNGER
PREV DISCUSSION... /ISSUED 218 AM CDT SAT MAY 16 2015/
DISCUSSION...SURFACE MAP AT 06Z SHOWS AN INCREASING SOUTHERLY
FLOW AS THE NEXT ACTIVE WEATHER SYSTEM DEEPENS OUT WEST. EARLIER
SHOWERS HAVE ALL BUT DISSIPATED ACROSS MIDDLE TENNESSEE, WITH
MINIMAL ACTIVITY EXPECTED OVERNIGHT. LOOK FOR MORE WIDESPREAD
SHOWERS TODAY AS A WEAK UPPER TROUGH PROVIDES SOME FOCUSING FOR
DEEPER MOISTURE, ALTHOUGH THE FORECAST MODEL SOUNDINGS SHOW ONLY
WEAK INSTABILITY TODAY. THUS, THUNDERSTORMS WON`T BE WIDESPREAD;
MOST OF TODAY`S ACTIVITY WILL BE SHOWERS ONLY.
TOMORROW, WE CAN EXPECT A GREAT DEAL MORE INSTABILITY, BUT LESS
MOISTURE CONTENT, SO POP`S ON SUNDAY WILL BE LOWER BUT THE CHANCE
OF STORMS WILL BE GREATER. AT THIS TIME, WE ARE EXPECTING GENERAL
THUNDERSTORMS ONLY, ALTHOUGH THE NEW DAY 2 CONVECTIVE OUTLOOK FROM
THE SPC DOES BRING A MARGINAL RISK RIGHT UP TO OUR DOORSTEP, SO A
FEW STORMS SUNDAY MAY AT LEAST BE STRONG. FROPA WILL LIKELY OCCUR
MONDAY EVENING. AFTER A BRIEF SPELL OF HIGH PRESSURE, A FOLLOW-UP
SYSTEM WILL MOVE THROUGH THURSDAY, BUT WITH MINIMAL EFFECTS.
TEMPERATURES NEXT WEEK WILL BE SLIGHTLY COOLER THAN THIS WEEK`S,
BUT NO SIGNIFICANT FLUCTUATIONS ARE EXPECTED THROUGH DAY 7.
ROSE
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
55
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1049 AM CDT SAT MAY 16 2015
.UPDATE...
AN AREA OF SHOWERS CONTINUE TO MOVE NORTH OVER PORTIONS OF WEST
TENNESSEE...NORTHEAST ARKANSAS...AND THE MISSOURI BOOTHEEL. THIS
AREA SHOULD MOVE INTO KENTUCKY AND MISSOURI BETWEEN 12-1 PM.
MEANWHILE...DRY CONDITIONS ARE CURRENTLY OCCURRING OVER NORTH
MISSISSIPPI. THE LATEST HRRR SHOWS ADDITIONAL DEVELOPMENT
OCCURRING ACROSS SOUTHERN MISSISSIPPI THAT WILL MOVE INTO NORTH
MISSISSIPPI AROUND 2 PM. THE CONVECTION WILL EVENTUALLY SPREAD
INTO THE REST OF THE MIDSOUTH BETWEEN 3-5 PM. FORECAST LOOKS
GOOD...NO UPDATES ARE EXPECTED.
KRM
&&
.DISCUSSION... /ISSUED 430 AM CDT SAT MAY 16 2015/
A WET DAY IS IN STORE FOR THE MIDSOUTH TODAY...FINALLY SEEMS MORE
LIKE MAY ACROSS THE MIDSOUTH THAN WHAT WE HAVE EXPERIENCED THROUGH
MUCH OF THE FIRST HALF OF THE MONTH. AREAS OF RAIN AND A FEW
THUNDERSTORMS WERE ALREADY OCCURRING ACROSS THE MIDSOUTH EARLY THIS
MORNING. THE WET PATTERN WILL CONTINUE INTO MONDAY AND WILL NEED TO
MONITOR FOR THE POSSIBILITY OF FLOODING / FLASH FLOODING AS RAINFALL
AMOUNTS INCREASE OVER TIME THROUGH THE WEEKEND INTO MONDAY.
A LARGE UPPER LEVEL LOW WAS LOCATED OVER THE WESTERN UNITED
STATES WITH AN UPPER LEVEL RIDGE ALONG THE SOUTHEAST COAST. A
SOUTHERLY WIND FLOW BETWEEN THESE TWO SYSTEMS WAS PUSHING ABUNDANT
MOISTURE INTO THE MIDSOUTH FROM THE GULF OF MEXICO. AN UPPER LEVEL
SHORT WAVE WAS LOCATED OVER EAST TX AND WILL MOVE NORTHEASTWARD
THROUGH THE MIDSOUTH TODAY. OCCASIONAL SHOWERS AND SCATTERED
THUNDERSTORMS ARE EXPECTED ACROSS THE REGION TODAY. PRECIPITABLE
WATER VALUES WILL BE BETWEEN 1.8 AND 2.0 INCHES WITH SURFACE DEW
POINTS IN THE MIDDLE 60S TO NEAR 70 DEGREES. AS A RESULT...LOCALLY
HEAVY RAINFALL MAY RESULT IN FLOODING IN SOME LOCATIONS TODAY...BUT
NOT CONFIDENT ENOUGH THAT WILL BE WIDESPREAD ENOUGH FOR A FLASH FLOOD
WATCH ATTM. DID MENTION THE THREAT OF LOCALLY HEAVY RAINFALL
AND FLOODING IN THE HAZARDOUS WEATHER OUTLOOK FOR TODAY. INSTABILITY
LOOKS TO BE A LITTLE LESS THAN YESTERDAY WITH MORE WIDESPREAD RAIN
AND CLOUDS.
FOR TONIGHT...AN UPPER LEVEL TROUGH MOVES INTO THE CENTRAL PLAINS
WITH AN ASSOCIATED COLD FRONT STRETCHING FROM KS INTO TX. ORGANIZED
CONVECTION IS EXPECTED TO DEVELOP AHEAD OF THIS FRONT THROUGH THE
PLAINS PERHAPS APPROACHING NORTHEAST ARKANSAS LATE TONIGHT...ALTHOUGH
INSTABILITY DECREASING BY THAT TIME. WEAK UPPER LEVEL DISTURBANCES
EMBEDDED IN SOUTHWEST FLOW ALOFT WILL CONTINUE THE THREAT FOR
SCATTERED SHOWERS AND THUNDERSTORMS TONIGHT ACROSS THE MIDSOUTH.
SUNDAY...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR
WITH LOCALLY HEAVY RAINFALL A CONTINUING THREAT. THE UPPER LEVEL
TROUGH WILL PUSH TO THE NORTHEAST THROUGH THE CENTRAL PLAINS WITH
THE ASSOCIATED COLD FRONT REMAINING TO OUR WEST AND NORTH. THE
GREATEST THREAT OF SEVERE WEATHER APPEARS TO BE TO OUR NORTH. 0-6
KM BULK SHEAR VALUES ARE ONLY MARGINAL FOR ORGANIZED SHEAR WEATHER
NEAR EXTREME NORTHEAST ARKANSAS AND THE MO BOOTHEEL. HOWEVER...
WIND FIELDS WILL BE STRONGER ACROSS THE MIDSOUTH SUNDAY AS THE UPPER
LEVEL TROUGH MOVES TO OUR NORTH. THIS WILL ALLOW WARMER SURFACE
TEMPERATURES TO PUSH INTO THE MIDSOUTH CAUSING GREATER INSTABILITY
AND THE POSSIBILITY A FEW STRONG TO SEVERE THUNDERSTORMS. IF ANY
SEVERE THUNDERSTORMS DO DEVELOP...DAMAGING WIND AND LARGE HAIL
WOULD BE THE GREATEST SEVERE WEATHER THREATS.
A COLD FRONT WILL SAG INTO THE MIDSOUTH FROM THE NORTH MONDAY AS THE
UPPER LEVEL RIDGE ALONG THE SOUTHEAST COAST WEAKENS SOME WITH
LOWERING UPPER LEVEL HEIGHTS ACROSS THE MIDSOUTH. WILL ONCE AGAIN
NEED TO MONITOR FOR HEAVY RAINFALL AND FLOODING / FLASH FLOODING.
THE COLD FRONT WILL GRADUALLY PUSH THROUGH THE MIDSOUTH MONDAY NIGHT
AND TUESDAY WITH DECREASING CHANCES FOR RAIN FROM THE NORTH.
TEMPERATURES WILL BE A LITTLE COOLER WITH PASSAGE OF THE COLD FRONT.
FOR THE REMAINDER OF THE WORK WEEK...THE ECMWF AND GFS ARE NOT IN
VERY GOOD AGREEMENT ON HOW FAR SOUTH THE COLD FRONT PUSHES AND HOW
QUICKLY IT PUSHES BACK NORTH. NEVERTHELESS...THE MODELS DO INDICATE
A CHANCE OF SHOWERS...PERHAPS THUNDERSTORMS...WILL MOVE BACK INTO
THE REGION FROM THE WEST. THE ECMWF IS FASTER BRINGING THE THREAT
OF SHOWERS AND THUNDERSTORMS BACK INTO THE REGION AS QUICKLY AS
WEDNESDAY.
JCL
&&
.AVIATION...
12Z TAFS
AN AREA OF SHOWERS WITH ISOLATED LIGHTNING STRIKES IS CURRENTLY
BEING OBSERVED ACROSS MEM...JBR AND MKL. THIS WILL CONTINUE TO
LIFT NORTH THIS MORNING WITH LOW CIGS ACCOMPANYING IT. CIGS DOWN
TO MVFR AND OCCASIONALLY IFR AT TIMES ARE EXPECTED. EXPECT
REDEVELOPMENT OF SHOWERS AND THUNDERSTORMS DURING THE LATE MORNING
HOURS ACROSS ALL TERMINALS SO VCTS COVERS THIS POTENTIAL UNTIL
TIMING CAN BE NAILED DOWN. IT APPEARS THAT A LULL IN THE SHOWER
ACTIVITY WILL OCCUR LATE SATURDAY NIGHT INTO SUNDAY MORNING
ALTHOUGH WINDS WILL STAY ABOVE 10KTS THROUGH THE NIGHT FROM THE
SOUTH.
TVT
&&
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1133 PM CDT FRI MAY 15 2015
.UPDATE...
06 TAF DISCUSSION.
&&
.AVIATION...
LINE OF STORMS CROSSING TN RIVER WILL REACH CKV AROUND START OF
TAF PERIOD. LEANED HEAVILY ON LATEST HRRR FOR TIMING...AND EXPECT
-SHRA TO CONTINUE AT CKV THROUGH THE NIGHT...REACHING BNA BY 12Z
AND CSV BY 14Z. MIX OF -SHRA/-TSRA EXPECTED BY 15Z AT ALL
AIRPORTS AS INSTABILITY INCREASES WITH DAYTIME HEATING...WITH
-SHRA/-TSRA CONTINUING TO 16/21Z. VFR CIGS TO BECOME MVFR BY 15Z
AS PRECIP BECOMES MORE WIDESPREAD. LIGHT SOUTH WINDS ANTICIPATED
THROUGH THE TAF PERIOD WITH OCCASIONAL GUSTS TO 20 KNOTS.
SHAMBURGER
&&
.PREV DISCUSSION... /ISSUED 635 PM CDT FRI MAY 15 2015/
UPDATE...
IMPULSE TO RIDE NORTHEAST AND INFLUENCE THE WEATHER OVER THE MID
STATE TONIGHT. BEST PVA TRAJECTORY APPEARS TO BE OVER WESTERN
AREAS. FURTHERMORE...DEEPEST MOISTURE TO POOL OVER THAT REGION AS
WELL. LATEST RADAR TRENDS SHOWS SOME INITIAL CONVECTION KNOCKING
AT THE DOOR ALONG THE TN RIVER. WILL GO AHEAD AND UPDATE THE ZONES
TO REMOVE THE LATE AFTERNOON WORDING. ALSO...WILL INCREASE POPS TO
THE LIKELY LEVEL FAR WEST...WILL INCLUDE 50 POPS CENTRAL AREAS.
OTW...HUMID AIRMASS SHOULD PREVENT TEMPS FROM DROPPING MUCH
OVERNIGHT. MIN TEMPS SHOULD HOLD IN THE 60S SO NO CHANGES NEEDED.
UPDATE OUT SHORTLY.
PREV DISCUSSION... /ISSUED 623 PM CDT FRI MAY 15 2015/
AVIATION 00Z DISCUSSION...
SHOWER AND TSTM ACTIVITY WILL MAKE A RUN AT THE AREA...MAINLY AFT
06Z. THE CATALYST WILL BE AN OVERNIGHT SHORTWAVE WHICH WILL BE
RIDING NORTHWESTWARD THROUGH THE MID STATE. CIGS WILL LOWER
OVERNIGHT AND VSBYS SHOULD GENERALLY REMAIN AT 3SM OR GREATER.
CONVECTIVE COVERAGE WILL DECREASE AFT 18Z.
PREV DISCUSSION... /ISSUED 238 PM CDT FRI MAY 15 2015/
DISCUSSION...AFTER MORE THAN 2 WEEKS WITHOUT SIGNIFICANT RAIN FOR
MOST OF MID TN...SCATTERED THUNDERSTORMS HAVE DEVELOPED. THE
POTENTIAL FOR WET WX WILL CONTINUE THROUGHOUT THE WEEKEND...
ESPECIALLY ON SATURDAY. THIS IS GOOD NEWS TO MANY...BUT LOTS OF
OUTDOOR EVENTS WILL BE IN JEOPARDY.
FOR THE REMAINDER OF TODAY...SCATTERED SHOWERS AND STORMS WILL
CONTINUE WITH POPS AROUND 40 PERCENT. NO SIGNIFICANT BOUNDARIES
ARE EVIDENT TO INDICATE ANY SPECIFIC LOCATIONS THAT WILL BE
IMPACTED. THE ACTIVITY WILL TEND TO DIMINISH AS THE SUN SETS THIS
EVENING.
OVERNIGHT...A FEW SHOWERS OR STORMS WILL LINGER...AND THE ACTIVITY
MAY INCREASE AGAIN TOWARD DAYBREAK. A FEW AREAS OF FOG ARE POSSIBLE
WITH LOWS IN THE MUGGY 60S.
FOR SATURDAY...ALL SIGNS POINT TO LOTS OF SHOWERS AND THUNDERSTORMS.
LOW LEVEL SOUTHERLY FLOW WILL CONTINUE TO BRING MOIST AIR FROM THE
GULF WHILE SOUTHWEST FLOW ALOFT ADDS MOISTURE AND A COUPLE OF
SHORTWAVE TROUGHS. PRECIPITABLE WATER VALUES WILL APPROACH 2
INCHES...ESPECIALLY OVER OUR NORTHWEST COUNTIES. THE GREATEST
RAINFALL COVERAGE WILL BE SATURDAY MORNING THROUGH EARLY
AFTERNOON WITH THE MAIN SHORTWAVE. AFTER THAT...THE COVERAGE WILL
DECREASE...BUT THERE WILL CONTINUE TO BE PLENTY OF MOISTURE AND
ADEQUATE INSTABILITY TO GENERATE CLUSTERS OF SHOWERS AND
THUNDERSTORMS. RAINFALL AMOUNTS FOR SATURDAY WILL RANGE FROM ONE
QUARTER TO ONE INCH...WITH THE HIGHER TOTALS EXPECTED GENERALLY
OVER THE NORTHWEST HALF OF MID TN. BECAUSE OF THE RAIN AND
CLOUDS...WE WILL GO ON THE LOW SIDE OF GUIDANCE TEMPERATURES FOR
SATURDAY.
THE COVERAGE OF SHOWERS AND STORMS WILL DECREASE SATURDAY NIGHT
THROUGH SUNDAY...TO 40-50 PERCENT. CONDITIONS WILL REMAIN QUITE
MUGGY WITH LOWS IN THE MID TO UPPER 60S. LOWER RAIN COVERAGE AND
SOME INTERVALS OF SUNSHINE WILL BRING WARMER TEMPS ON
SUNDAY...MAINLY LOW TO MID 80S.
RAIN CHANCES WILL INCREASE AGAIN SUNDAY NIGHT INTO MONDAY AS A
COLD FRONT APPROACHES. ANOTHER QUARTER TO 1 INCH OF RAINFALL IS
EXPECTED SUNDAY NIGHT THROUGH MONDAY NIGHT. FORTUNATELY...WE DO
NOT EXPECT ANY WIDESPREAD OR ORGANIZED SEVERE WX.
COOLER AND DRIER AIR WILL FOLLOW THE FRONT FOR MIDWEEK. A COUPLE
OF DISTURBANCES WILL BRING A SMALL CHANCE FOR SHOWERS BY THURSDAY
THEN TRENDING WARM AND UNSETTLED AGAIN FOR NEXT WEEKEND.
13
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
55
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1028 AM CDT SAT MAY 16 2015
.UPDATE...
A QUICK LOOK AT THE ENVIRONMENT THIS MORNING FROM THE 12Z FORT
WORTH SOUNDING DOES SHOW SUBSIDENCE WAS RELATIVELY STRONGER THAN
EXPECTED LATE YESTERDAY BEHIND THE DEPARTING SHORTWAVE. HOWEVER...
LAPSE RATES ABOVE THE EML REMAIN STEEP AND MOISTURE RICH ENOUGH
THAT SOME HIT AND MISS SHOWERS AND STORMS ARE POSSIBLE OVER THE
REGION THIS AFTERNOON. TODAY. HIGH RES MODELS OUTSIDE OF THE
RAPID REFRESH/HRRR HAVE DELAYED ACTIVITY INTO THE WESTERN
COUNTIES UNTIL AFTER 00Z/7 PM. THE HRRR IS AN HOUR OR TWO SOONER
FOR CONVECTIVE POTENTIAL. WE WILL BE ISSUING A SPECIAL 18Z
SOUNDING EARLY THIS AFTERNOON TO RE-EVALUATE THE ENVIRONMENTAL
CHANGES.
WE HAVE TRIMMED BACK THE ARRIVAL FOR POSSIBLE DISCRETE SEVERE
STORMS TO VERY LATE THIS AFTERNOON FOR MAINLY YOUNG/JACK/AND
MONTAGUE COUNTIES WHERE AN ENHANCED RISK FOR SEVERE WEATHER
REMAINS. THE MAIN UNCERTAINTY WILL BE THE DELAYED TIMING OF THE
STRONGER MID-LEVEL HEIGHT FALLS/LARGE SCALE ASCENT AND THE MODEST
EML CURRENTLY IN PLACE. THE DRYLINE REMAINS WELL TO THE WEST
ACROSS EASTERN NEW MEXICO AND HAS A WAYS TO GO BEFORE REACHING OUR
WESTERN COUNTIES LATE TODAY. REGARDLESS...BY THIS EVENING SEVERE
STORMS WILL BE POSSIBLE ACROSS AREAS MAINLY NORTH OF I-20 AND WEST
OF I-35/35W WITH ALL MODES OF SEVERE WEATHER POSSIBLE.
HAVE MADE TIMING ADJUSTMENTS FOR THE DAYTIME PERIOD WITH ALL THESE
ITEMS IN MIND. AS THE SYSTEM BECOMES LINEAR TO THE LARGE SCALE
FORCING LATE THIS EVENING AND OVERNIGHT...IT WILL BE FED BY A
STRENGTHENING LLJ AND ASSOCIATED WAA. THE SEVERE THREAT WILL
BECOME MORE LOCALIZED WHILE THE HYDROLOGICAL THREAT RAMPS WITH
POSSIBLE TRAINING STORMS WITH VERY HEAVY RAINFALL WITH PWAT
VALUES WELL ABOVE NORMAL. CURRENT FLOOD PROBLEMS WILL ONLY BE
EXACERBATED WITH FLASH FLOODING POSSIBLE DURING THE OVERNIGHT
HOURS INTO SUNDAY MORNING. A FLASH FLOOD REMAINS IN EFFECT FOR
MOST OF THE AREA THROUGH TONIGHT...THEN FOR OUR CENTRAL TEXAS
COUNTIES ON SUNDAY.
05/
&&
.AVIATION...
/ISSUED 656 AM CDT SAT MAY 16 2015/
MVFR CEILINGS WILL PREVAIL AT ALL TAF SITES THROUGH THE MORNING
WITH CEILINGS LIFTING AND SCATTERING THIS AFTERNOON. VFR
CONDITIONS ARE EXPECTED THIS EVENING EXCEPT IN AND NEAR
THUNDERSTORMS.
LIFT WILL BE ON THE INCREASE THROUGH THE AFTERNOON AS A POWERFUL
UPPER LOW MOVES TOWARD THE NORTHERN HIGH PLAINS. WE EXPECT
THUNDERSTORMS TO DEVELOP WEST OF THE TAF SITES LATE THIS
AFTERNOON. THESE STORMS SHOULD ORGANIZE INTO A LINE AND MOVE EAST
DURING THE EVENING. THE BEST WINDOW OF TIME FOR THE STORMS TO MOVE
ACROSS THE METROPLEX TAF SITES WILL BE BETWEEN 05Z AND 09Z AND
SLIGHTLY LATER IN WACO.
A SOUTH WIND WILL PREVAIL THROUGH TONIGHT AT SPEEDS BETWEEN 11
AND 16 KNOTS WITH SOME HIGHER GUSTS DURING THE DAY. WINDS COULD
BECOME STRONG AND GUSTY AS THE LINE OF THUNDERSTORMS MOVES THROUGH
TONIGHT.
79
&&
.PREV DISCUSSION... /ISSUED 338 AM CDT SAT MAY 16 2015/
WV SAT LOOP SHOWS A BROAD UPPER LOW OVER THE INTERMOUNTAIN REGION
WITH A SHORT WAVE TROUGH OVER SOUTHERN ARIZONA AND ANOTHER OVER
WESTERN NEVADA. THE SOUTHERN RADAR MOSAIC THIS MORNING SHOWS
SIGNIFICANT CONVECTION ALONG A DRYLINE/PACIFIC COLD FRONT OVER THE
TEXAS HIGH PLAINS AND PANHANDLE REGION WHICH WILL CONTINUE TO
ADVANCE TOWARD NORTH/CENTRAL TEXAS TODAY. AS THE CONVECTION ENTERS
THE FAR WESTERN COUNTIES LATE THIS AFTERNOON...THERE COULD BE SOME
MARGINALLY SEVERE TO SEVERE THUNDERSTORMS DUE TO HIGH CAPE AND
0-3KM SHEAR OF 35-40 KNOTS. ANY DISCRETE SUPERCELL WILL NEED TO BE
WATCHED FOR STRONG ROTATING UPDRAFTS THAT COULD PRODUCE A
TORNADO.
COME THIS EVENING...THE STORMS SHOULD BECOME MORE LINEAR AND MORE
PARALLEL TO THE UPPER FLOW WHICH WILL INCREASE THE POTENTIAL FOR
ECHO TRAINING...HEAVY RAINFALL AND FLASH FLOODING DURING THE
OVERNIGHT HOURS. THE HEAVY RAIN POTENTIAL WILL CONTINUE THROUGH
SUNDAY MORNING OVER THE SOUTHEAST ONE HALF OF THE CWA...THUS WE
HAVE DECIDED TO MOVE THE WATCH SOUTHEASTWARD AND EXTEND IT THROUGH
SUNDAY AFTERNOON AS SOME AREAS MAY RECEIVE AN ADDITIONAL 1/2 TO 1
INCH DURING THE DAY. THE WATCH MAY NEED TO BE EXTENDED FURTHER
INTO SUNDAY NIGHT IF THE QPF OF THE GFS AND ECMWF PANS OUT. WE WILL
TACKLE PROBLEM ON THE NEXT COUPLE OF SHIFTS.
SINCE THE AIR MASS DOES NOT CHANGE MUCH ON MONDAY...WE WILL
CONTINUE TO CARRY A CHANCE OF CONVECTION DURING THE DAY WITH A
LESSER CHANCE MONDAY NIGHT. A COLD FRONT WILL MOVE SOUTH OF THE
RED RIVER LATE MONDAY NIGHT AND THEN STALL ALONG THE I-20 CORRIDOR
ON TUESDAY. THE FRONT WILL MOVE BACK NORTH TUESDAY NIGHT ONLY TO
COME BACK SOUTH LATER IN THE WEEK AS OUR NEXT UPPER SYSTEM MOVES
THROUGH THE DESERT SOUTHWEST AND INTO THE CENTRAL ROCKIES. THE
SHORT WAVE ENERGY ASSOCIATED WITH THIS SYSTEM SHOULD PASS FARTHER
TO THE NORTHWEST OF NORTH TEXAS...THUS WE/LL KEEP POPS MOSTLY IN
THE CHANCE CATEGORY TUESDAY THROUGH WEDNESDAY. HOWEVER...THERE IS
A FAIRLY STRONG CONVECTIVE SIGNAL BEING ADVERTISED WEDNESDAY NIGHT
PER THE GFS/ECMWF MODELS AND HAVE ADDED LIKELY POPS TO THE RED
RIVER REGION FOR THE WEDNESDAY NIGHT PERIOD.
THURSDAY THROUGH FRIDAY...WE/LL KEEP CHANCE POPS ACROSS THE CWA
AS ANOTHER UPPER TROUGH DROPS DOWN THE WEST COAST AND INTO THE
SOUTHWEST BY LATE NEXT WEEK. THIS WILL RESULT IN SLIGHT UPPER
RIDGING ON THURSDAY FOLLOWED BY SOUTHWESTERLY FLOW ALOFT AND A
COUPLE OF SHORTWAVE RIPPLES ON FRIDAY.
THERE WILL BE LITTLE CHANGE IN MAX/MIN TEMPERATURES THROUGH THIS
FORECAST...HIGHS MOSTLY 80-85 AND LOWS MOSTLY IN THE MID-UPPER
60S. 75
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 82 69 84 70 83 / 30 80 40 40 40
WACO, TX 83 71 83 70 83 / 30 70 70 50 50
PARIS, TX 81 69 82 69 81 / 40 80 60 50 40
DENTON, TX 80 68 84 68 84 / 30 80 30 40 30
MCKINNEY, TX 81 69 83 68 83 / 30 80 40 50 40
DALLAS, TX 82 69 85 70 84 / 30 80 50 50 40
TERRELL, TX 83 71 84 69 82 / 30 70 60 60 40
CORSICANA, TX 83 72 83 70 81 / 30 50 70 50 50
TEMPLE, TX 84 72 83 70 83 / 30 50 60 40 50
MINERAL WELLS, TX 81 66 84 67 84 / 40 80 30 20 30
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH FROM 4 PM CDT THIS AFTERNOON THROUGH SUNDAY
MORNING FOR TXZ091>095-100>107-115>121-129>134-141.
FLASH FLOOD WATCH FROM SUNDAY MORNING THROUGH SUNDAY AFTERNOON
FOR TXZ147-148-158-160>162-174-175.
FLASH FLOOD WATCH FROM 4 PM CDT THIS AFTERNOON THROUGH SUNDAY
AFTERNOON FOR TXZ122-123-135-142>146-156-157-159.
&&
$$
79/05
YOU CAN SEE AN ILLUSTRATED VERSION OF THIS FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS PORTLAND
220 PM PDT SAT MAY 16 2015
.SYNOPSIS...A LARGE BUT WEAK UPPER LEVEL LOW PRES SYSTEM WILL REMAIN
OVER THE REGION THROUGH MUCH OF THE COMING WEEK. A WEAK LOW LEVEL
OFFSHORE FLOW SUN AND MON WILL LEAD TO WARMER TEMPS AS WELL AS A
CHANCE FOR SHOWERS AND THUNDERSTORMS. ONSHORE FLOW WILL RETURN TUE
FOR A LITTLE COOLING AGAIN BUT A CONTINUED CHANCE OF SHOWERS.
THROUGH THE END OF THE WEEK TEMPERATURES WILL REMAIN CLOSE TO
SEASONAL NORMALS WITH ENOUGH INSTABILITY FOR A FEW SHOWERS.
&&
.SHORT TERM...RADAR AND SURFACE OBSERVATIONS HAVE SHOWN A FEW LIGHT
SHOWERS OVER THE NORTHERN PART OF THE FORECAST AREA EARLY THIS
AFTERNOON...THE RESULT OF SHALLOW INSTABILITY AND WEAK TROUGHINESS
ALOFT. A NEW UPPER LOW SEEN IN WATER VAPOR PICTURES WELL OFFSHORE
BETWEEN 135 AND 140W IS EXPECTED TO SLIDE SLOWLY SE INTO CA BY MON.
THIS TURNS THE MID AND UPPER LEVEL FLOW MORE TO THE SE WITH TIME...
WHILE WARMER TEMPS AT H8 WRAP IN FROM THE E. WITH REDUCED CLOUD
COVER AND WARMER H8 TEMPS WILL SEE TEMPS WARM BACK TO A LITTLE ABOVE
NORMAL FOR SUN AND MON. OVERALL THIS LEADS TO PROGRESSIVE
DESTABILIZATION OF THE ATMOSPHERE...WITH NAM AND GFS MODEL SOUNDINGS
INDICATING SOME INSTABILITY DEVELOPING OVER THE CASCADES BY SUN
AFTERNOON. BETTER INSTABILITY IS DEPICTED MON WITH AN EL AS HIGH AS
35K FT. THE POTENTIAL INSTABILITY ALSO EXTENDS AS FAR W AS THE COAST
RANGE MON. FORCING MECHANISM IS NOT QUITE AS OBVIOUS EITHER DAY AS
THE MON SHORTWAVE DEPICTED PREVIOUSLY BY GFS AND ECMWF IS MUCH
WEAKER. OVERALL WILL KEEP POPS CONSERVATIVE SUN MAINLY OVER THE
CASCADES...THEN INDICATE BETTER CHANCES FOR MON WITH LIKELY POPS
OVER THE CASCADES BASED ON GOOD INSTABILITY AND SOME DIFFLUNECE
ALOFT. WILL ALSO CARRY THE SLIGHT CHANCE FOR THUNDER AS FAR W AS THE
COAST RANGE BASED ON EASTERLY COMPONENT TO THE FLOW AND INSTABILITY.
AS THE CA LOW MOVES WELL E TOWARDS UTAH TUE...LOW LEVEL FLOW TURNS
BACK ONSHORE. THIS EXPECTED TO PUSH MARINE CLOUDS BACK INLAND FOR
COOLER TEMPS. MODEL SOUNDINGS HOWEVER CONTINUE TO INDICATE MARGINAL
INSTABILITY ALOFT WITH STILL SOME MID AND UPPER LEVEL MOISTURE. WILL
NEED TO KEEP A CHANCE FOR SHOWERS IN THROUGH TUE.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY...BROAD UPPER-LEVEL LOW
REMAINS IN PLACE THROUGH THE WEEK...KEEPING COOLER CLOUDY MARINE
AIRMASS IN PLACE OVER THE REGION THROUGH FRIDAY. THIS WILL KEEP THE
AREA UNDER CLOUDY WEATHER WITH OCCASIONAL SHOWERS. MOISTURE STARTS
TO WANE LATER IN THE WEEK...WHICH WILL LIMIT SHOWERS TO THE
CASCADES. THE MODELS ARE SUGGESTING THAT AN UPPER LEVEL RIDGE TRIES
TO PUSH THE UPPER-LEVEL LOW OFF TO THE EAST FOR SATURDAY WHICH COULD
DRY WEATHER OUT FOR THE WEEKEND...BUT CONFIDENCE IS LOW ON TIMING
AND WHETHER THIS WILL ACTUALLY OCCUR THIS FAR OUT IN THE FORECAST
PERIOD. -MCCOY
&&
.AVIATION...IFR CIGS WITH PERIODS OF IFR VSBYS WITH LIGHT DRIZZLE
WILL CONTINUE AT THE COAST AT LEAST THROUGH 19Z AND PERHAPS INTO
THE AFTERNOON THROUGH 21Z BEFORE IMPROVING TO MVFR. EXPECT A
RETURN TO IFR CIGS LATE OVERNIGHT AROUND 10Z. INLAND...MODEL TIME
HEIGHT MOISTURE SUPPORTS MARINE STRATUS CONTINUING OVERNIGHT WITH
A FAVORING OF THE MORE PESSIMISTIC GFS. NAM12 APPEARS TO CLEAR
THE SKIES TOO FAST AND ESPECIALLY GIVEN THE LONG FETCH OF UPSTREAM
MOISTURE WHICH SHOULD CONTINUE TO REINFORCE THE MARINE LAYER. AS
SUCH...EXPECT THE LARGELY VFR CIGS NOW TO LOWER THIS EVENING BACK
TOWARD THE 025 AGL MARK WHERE THEY WILL PERSIST THROUGH 12Z AT
LEAST AND LIKELY THROUGH 18Z BEFORE SHOWING SIGNS OF BREAKING UP.
KPDX AND APPROACHES...VFR STRATUS CIGS AROUND 030-040 WILL LIKELY
STAY IN PLACE THROUGH AT LEAST 12Z. CONFIDENCE HAS IMPROVED WITH A
PERSISTENT VFR STRATUS TO STAY IN PLACE BUT LIKELY LOWER CLOSER
TO THE 025 MARK AROUND 06Z. FIRST IMPRESSION HAS THE 025 STRATUS
DECK REMAINING IN PLACE THROUGH THE MORNING PUSH WITH HINTS OF
CLEARING AFTER 16Z AT THE EARLIEST. /JBONK
&&
.MARINE...WEAK SURFACE HIGH PRESSURE OFFSHORE WILL COMBINE WITH
SURFACE LOW PRESSURE INLAND TO PRODUCE MAINLY NORTHWEST TO NORTH
WINDS FOR THE WEEK AHEAD. WIND GUSTS STAY BELOW 20 KTS FOR THE
ENTIRE FORECAST.
RELATIVELY MILD SWELL CONDITIONS FOR THE WEEK AHEAD. A COUPLE
SMALLER SWELL TRAINS COMBINE FOR HEIGHTS OF 4 TO 5 FEET. LONGER
PERIOD SWELLS AROUND 15 TO 17 SECONDS WILL SHORTEN INTO THE 11 TO
14 SECOND RANGE BY MID WEEK.
EXPECT CHOP DURING THE EBBS BUT WITH A HEIGHT OF 5 FEET AND MAYBE
7 FEET ON THE VERY STRONG OVERNIGHT EBB...WILL NOT MEET CRITERIA
AS WIND SPEEDS DO NOT SUPPORT CREATING MAIN CHANNEL BREAKERS.
/JBONK
&&
.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
National Weather Service Spokane WA
1247 PM PDT SAT MAY 16 2015
.SYNOPSIS...
Scattered showers with embedded thunderstorms will be possible
for the next several days. The best chance of widespread showers
and isolated thunderstorms will be late this afternoon and
Sunday, especially over north Idaho and Northeast Washington.
Seasonably mild conditions will continue through the next week
with showers possible over the higher terrain.
&&
.DISCUSSION...
A minor update has been sent to extend the band of wrap around
rain slightly to the west to include the Lewiston area. Radar
trends as well as the HRRR suggest this area of rain will shift
south and east of the Lewiston area and Camas Prairie by late
morning so this is not expected to last much longer. For this
afternoon the HRRR shows increasing shower and isolated
thunderstorm development over NE Washington Mountains and Idaho
Panhandle, and then drifting southwestward into the Spokane area,
Okanogan Highlands, and Palouse by late this afternoon or early
evening as a low level boundary helps initiate convection.
Elevated dew points currently in the mid 40s to lower 50s around
Spokane, Deer Park, and Sandpoint along with an eroding mid level
cloud deck should allow for some morning and afternoon sun which
will allow for increased surface heating to help inititate
convection. It is this area that the 06z GFS has the best
instability with uncapped CAPE values as high as 500-1000 J/KG. Brief
heavy rain...small hail...and wind gusts to around 30 mph are the
main threats with these storms. JW
&&
.AVIATION...
18z TAFS: Main concern will the development of showers and
isolated thunderstorms over NE Washington and North Idaho through
early this evening. KGEG/KSFF/KCOE are most favored for this
activity...although with only isolated coverage expected only went
with VCTS in the TAF between 23z-02z based on HRRR timing which is
currently lining up well with radar data. This activity should
decrease after sunset although showers may increase in North
Central WA overnight where the best mid level instability will
lie ahead of a closed low near Vancouver Island. Mainly VFR
conditions are expected through 18z Sun...although in heavier
showers or storms a lowering of visibility is likely. Also
overnight an increase in NE winds for KGEG/KSFF/KCOE should limit
the fog/stratus potential. The NAM shows the best stratus
potential overnight at KPUW...although confidence is low-moderate
of this occurring as the GFS shows drying in the boundary layer
late tonight/early Sunday as easterly flow begins to increase. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 72 51 69 49 72 49 / 40 60 10 10 10 10
Coeur d`Alene 68 48 69 45 72 47 / 70 60 10 10 10 10
Pullman 65 49 67 44 71 45 / 40 60 30 20 20 20
Lewiston 70 54 73 51 76 53 / 40 60 30 30 30 20
Colville 77 52 72 48 74 50 / 40 60 20 10 10 10
Sandpoint 69 48 69 40 70 41 / 70 50 10 10 10 10
Kellogg 65 46 68 43 70 44 / 70 60 10 10 10 10
Moses Lake 78 53 73 50 77 51 / 10 30 40 20 10 10
Wenatchee 78 55 72 54 78 55 / 10 50 50 20 10 10
Omak 79 52 72 50 76 49 / 10 50 50 20 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1100 PM CDT SUN MAY 17 2015
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 303 PM CDT SUN MAY 17 2015
MAIN CONCERN IS SEVERE THREAT LATE THIS AFTERNOON INTO THIS
EVENING.
LATEST WATER VAPOR SATELLITE IMAGERY SHOWS UPPER LEVEL LOW/TROUGH
OVER EASTERN SOUTH DAKOTA AND WESTERN MINNESOTA...IN ADDITION A
SHORTWAVE TROUGH OVER SOUTHEAST NEBRASKA AND SOUTHWEST IOWA.
LATEST 19Z SURFACE ANALYSIS INDICATES SURFACE LOW OVER SOUTHEAST
NORTH DAKOTA AND WEST CENTRAL MINNESOTA...WITH A COLD FRONT
EXTENDING SOUTH INTO WESTERN IOWA. LATEST SATELLITE IMAGERY SHOWS
STRATUS OVER FORECAST AREA BECOMING MORE CELLUAR AND SCATTERED
SHOWERS DEVELOPED OVER NORTH CENTRAL WISCONSIN AND PARTS OF
SOUTHEAST MINNESOTA PER LATEST ARX RADAR.
WITH THE STRATUS DECK OVER MUCH OF THE REGION THROUGH EARLY
AFTERNOON HOURS...THIS HAS LIMITED INSTABILITY OVER FORECAST AREA
THIS AFTERNOON...WITH THE 17.19Z LAPS SHOWING 200-800 J/KG OVER
FORECAST AREA AND AROUND 1000-1200 J/KG ALONG AND JUST AHEAD OF
THE COLD FRONT. THE LATEST SPC MESOSCALE ANALYSIS INDICATES 40
KNOTS OF 0-6KM SHEAR OVER FORECAST AREA...WITH THE BEST SHEAR IN
THE 0-3KM SHEAR PER 17.18Z RAP OF 30 TO 40 KNOTS ALONG AND AHEAD
OF SURFACE FRONT. SPC MESOSCALE 0-1KM SHEAR INDICATES ABOUT 10 TO
20 KNOTS ALONG AND AHEAD OF COLD FRONT. WITH MINIMAL INSTABILITY
AND SHEAR DECREASING OVER FORECAST AREA...SEVERE THREAT OVER
FORECAST AREA HAS DECREASED. HOWEVER CANNOT RULE OUT AN ISOLATED
SEVERE THUNDERSTORM WITH DAMAGING WINDS...LARGE HAIL OR POSSIBLY
AN ISOLATED TORNADO LATE THIS AFTERNOON INTO THIS EVENING.
MONDAY...FORECAST AREA REMAINS UNDER THE INFLUENCE OF THE UPPER
LEVEL LOW/TROUGH OVER SOUTHERN ONTARIO AND LAKE SUPERIOR. THE
17.12Z GFS/NAM INDICATE COLD AIR ADVECTING INTO THE FORECAST
AREA...WITH 925MB TEMPERATURES FALLING TO 0 TO MINUS 2 DEGREES
CELSIUS OVER THE FORECAST AREA. HIGH TEMPERATURES ARE EXPECTED TO
BE WELL BELOW NORMAL...WITH READINGS IN THE UPPER 40S TO LOWER 60S
ACROSS THE FORECAST AREA. TIGHT PRESSURE GRADIENT WILL ALLOW FOR
WINDS TO BE SUSTAINED AT 15 TO 20 KNOTS AND GUSTS OF 20 TO 30
KNOTS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 303 PM CDT SUN MAY 17 2015
TUESDAY INTO WEDNESDAY...SURFACE RIDGE BUILDS INTO MUCH OF MINNESOTA
AND NORTHERN WISCONSIN. SUBSIDENCE UNDERNEATH THE RIDGE SHOULD ALLOW
FOR DRY WEATHER AND SLIGHTLY BELOW NORMAL TEMPERATURES TUESDAY AND
TUESDAY NIGHT. PATCHY TO AREAS OF FROST IS POSSIBLE ACROSS PARTS OF
CENTRAL WISCONSIN TUESDAY NIGHT INTO WEDNESDAY MORNING. MID TO HIGH
CLOUDS STREAMING AHEAD OF SHORTWAVE TROUGH SOUTHWEST OF FORECAST
AREA MAY NOT ALLOW TEMPERATURES TO FALL INTO THE LOWER TO MIDDLE
30S. TIMING OF MOISTURE ABOVE 700MB WILL BE THE BIGGEST FACTOR AND
THIS IS EVIDENT BY THE 17.12Z GFS/NAM.
WEDNESDAY...SHORTWAVE TROUGH FLATTENS UPPER LEVEL SHORTWAVE RIDGE
WEDNESDAY OVER NEBRASKA AND IOWA. WITH DRY AIRMASS IN PLACE OVER
FORECAST AREA AND THE DEEPER FORCING/LIFT ASSOCIATED WITH SHORTWAVE
TROUGH SOUTH OF FORECAST AREA...HIGHER PRECIPITATION/SHOWER
CHANCES WILL REMAIN MAINLY SOUTH OF FORECAST AREA WEDNESDAY.
HOWEVER...THE 17.12Z GFS/NAM SUGGEST 500-300MB PV ADVECTION ALONG
THE MINNESOTA AND IOWA BORDER DURING THE DAY WEDNESDAY. WILL
INTRODUCE A SMALL PRECIPITATION CHANCE OVER THE EXTREME SOUTH PART
OF THE FORECAST AREA...AS THE 17.12 GFS/NAM DEVELOP LIGHT QPF...A
HUNDREDTH OR TWO...OVER THE EXTREME SOUTHERN PART OF THE FORECAST
AREA.
MAIN FORECAST CONCERNS FROM WEDNESDAY NIGHT INTO MEMORIAL DAY
WEEKEND ARE PRECIPITATION CHANCES FOR MEMORIAL DAY WEEKEND. THE
17.12Z GFS/ECMWF/GEM ARE IN GOOD AGREEMENT IN BUILDING IN
SHORTWAVE/SURFACE RIDGE INTO THE UPPER MIDWEST AND GREAT LAKES
REGION WEDNESDAY NIGHT INTO FRIDAY PROVIDING DRY WEATHER AND
SLIGHTLY TO NEAR NORMAL TEMPERATURES BOTH DAYS. FOCUS TURNS TO
MEMORIAL DAY WEEKEND...WHERE THE 17.12Z GFS/ECMWF ARE IN GOOD
AGREEMENT IN EJECTING PIECES OF ENERGY OUT OF UPPER LEVEL LOW/TROUGH
OVER THE SOUTHWEST UNITED STATES INTO THE CENTRAL UNITED STATES.
BOTH THE 17.12Z GFS/ECMWF SHOW INCREASING LOW LEVEL JET/MOISTURE
TRANSPORT/CONVERGENCE AND LIFT/FORCING SATURDAY INTO SUNDAY INTO THE
FORECAST AREA. WILL CONTINUE TO TREND OF SHOWERS AND THUNDERSTORMS
SATURDAY INTO SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM CDT SUN MAY 17 2015
LOW CLOUDS ADVANCING QUICKER EAST THAN ORIGINALLY ANTICIPATED...AND
WILL BE ACROSS KRST/KLSE AROUND 06Z. ONCE IN...EXPECT THE MVFR
CLOUDS TO HOLD INTO THE MORNING HOURS...WITH SOME DIURNAL BUMP UP
INTO VFR BY MID/LATE MORNING MON. LIKELY SEE A RETURN TO MVFR CIGS
MONDAY EVENING.
STRONG WINDS AT KRST FOR THE FIRST PART OF THE OVERNIGHT...SUSTAINED
20 TO 25 WITH GUSTS UPWARDS OF 35 KTS. MODELS SUGGEST IMPROVEMENT BY
09Z OR SO...BUT WINDS SHOULD CONTINUE NEAR 20 KTS WITH HIGHER GUSTS
INTO EARLY MON EVENING AT KRST. SLIGHTLY LESS AT KLSE. THERE WILL BE
IMPROVEMENT LATER MONDAY NIGHT AS HIGH PRESSURE STARTS TO APPROACH
FROM THE NORTHERN PLAINS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DTJ
LONG TERM...DTJ
AVIATION...RIECK
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
834 PM CDT SUN MAY 17 2015
.UPDATE...
LOOKS LIKE ANY CHANCE FOR SHOWERS HAS ENDED. THE DRY AIR HAS
OVERSPREAD THE AREA AHEAD OF AN APPROACHING COLD FRONT. THE FRONT
WON/T HAVE ANYTHING TO WORK WITH AND WILL COME THROUGH DRY LATE
TONIGHT THROUGH ABOUT MID MORNING ON MONDAY. SO...LOOK FOR A
FAIRLY QUIET NIGHT WITH WINDS REMAINING SOMEWHAT ELEVATED AND
TEMPS FALLING BACK INTO THE MID 50S TO LOWER 60S.
&&
.AVIATION/06Z TAFS/...
VFR CONDITIONS EXPECTED THROUGH THE TAF PERIOD. THE ONLY
OPERATIONAL CONCERN WILL BE LOW LEVEL WIND SHEAR THROUGH ABOUT
10-12Z MONDAY. WINDS AT 2000FT WILL BE AROUND 35-40KTS WHILE AT
THE SURFACE THEY MAY DIMINISH TO AROUND 10KTS. A COLD FRONT WILL
SWEEP ACROSS THE AREA...DRY...FROM ABOUT 10-14Z MONDAY WITH WINDS
BECOMING WESTERLY BEHIND THE FRONT. WINDS WILL BE GUSTY TO NEAR 25
KNOTS MONDAY AFTERNOON...DIMINISHING BY MONDAY EVENING.
&&
.PREV DISCUSSION... /ISSUED 330 PM CDT SUN MAY 17 2015/
SHORT TERM...
TONIGHT...FORECAST CONFIDENCE MEDIUM.
THE HRRR MODEL HAS BEEN CONSISTENT TODAY AND SO FAR CORRECT. OTHER
MESO MODELS ARE SIMILAR. A LINE OF SHOWERS AND THUNDERSTORMS WAS
ORIENTED ROUGHLY NORTH TO SOUTH ACROSS THE CENTRAL MKX FORECAST AREA
AT 2 PM THIS AFTERNOON. THIS LINE IS SLOWLY TRACKING EAST WITH MID
LEVEL VORTICITY ADVECTION. THESE ARE WORKING OFF THE HIGHER CAPE
AXIS THAT DEVELOPED OVER INLAND WI AREAS AND ALSO WEAK SURFACE
CONVERGENCE. THE CONVECTION IS LOW-TOPPED SINCE MID LEVEL LAPSE
RATES ARE WEAK. THEREFORE... MANY OF THE ECHO TOPS ARE BENEATH THE
FREEZING LEVEL OF 12.5 KFT AND ARE NOT EVEN PRODUCING THUNDER.
SEVERAL CELLS HAVE TOPS AROUND 20 KFT AND WE ARE SEEING CLOUD TO
GROUND LIGHTNING STRIKES WITH THEM.
PER THE HRRR AND OTHER MESO MODELS... THESE SHOWERS WILL CONTINUE
EAST THROUGH 6 PM... ALL THE WAY THROUGH MILWAUKEE. EXPECT HEAVY
DOWNPOURS. BRIEF LOCALIZED FLOODING IS POSSIBLE IN URBAN AREAS.
THERE IS A BREAK BEHIND THIS LINE OF SHOWERS AND STORMS LATE THIS
AFTERNOON. LOOK FOR GUSTY SOUTH-SOUTHWEST WINDS AS THE LOW LEVELS
MIX OUT AND DEWPOINTS DROP TO AROUND 60. CAPE/INSTABILITY WILL LOWER
IN THIS AREA. 0-6KM BULK SHEAR WILL REMAIN HIGH... AROUND 40 KT.
THERE IS ONE MORE CHANCE FOR STORMS ACROSS SOUTHERN WI THIS
EVENING... BUT THE CHANCE IS BECOMING VERY LOW. THE HRRR... NAMNEST
AND OTHER MESO MODELS ARE SHOWING QUITE A DRY SCENARIO FOR OUR AREA.
THE FEATURE WE HAVE BEEN FOCUSING OUR ATTENTION ON FOR SEVERE
POTENTIAL IS AN UPPER LEVEL WAVE AND A SURFACE PRE-FRONTAL TROUGH
ASSOCIATED WITH AN OCCLUDING LOW PRESSURE SYSTEM OVER THE EASTERN
DAKOTAS AND WEST CENTRAL MN. THE UPPER WAVE NOW LOOKS LIKE IT WILL
COME THROUGH SOUTHERN WI A LITTLE AHEAD OF THE PRE-FRONTAL TROUGH...
SO DEVELOPMENT OF STORMS WILL BE HARDER TO ACHIEVE. IF ANY STORMS
DEVELOP... THE CAPE WILL BE MARGINAL AND SHEAR WILL BE HIGH. THUS...
THERE IS STILL A SMALL RISK FOR SEVERE. SPC STILL HAS OUR AREA IN A
SLIGHT RISK FOR SEVERE STORMS.
SKIES SHOULD CLEAR LATE THIS EVENING WITH THE DRY AIR WRAPPING INTO
SOUTHERN WI AS THE SURFACE LOW TRACKS INTO NORTHEAST MN. WINDS WILL
SHIFT TO THE SW AND WEST TOWARD MORNING.
MONDAY...FORECAST CONFIDENCE HIGH.
THE SURFACE/925MB COLD FRONT WILL TRACK THROUGH SOUTHERN WI DURING
THE DAY MONDAY. IT WILL BE SLOW TO REACH SOUTHEAST WI... THUS MAX
TEMPS WILL BE IN THE MID 70S THERE. THE DELLS AREA WILL BE COOLEST
WITH HIGHS AROUND 60. EXPECT BRISK AND GUSTY WEST WINDS DUE TO A
STRONG PRESSURE GRADIENT OVER THE REGION.
MONDAY NIGHT THROUGH WEDNESDAY...FORECAST CONFIDENCE MEDIUM.
THE UPPER LOW OVER NRN MN WILL BECOME AN OPEN WAVE AND MOVE ACROSS
LAKE SUPERIOR AND INTO ONTARIO CANADA MON NT. A WEAKER SHORTWAVE
TROUGH WILL ALSO MOVE ACROSS CENTRAL WI DURING THAT TIME. THE
SHORTWAVE WILL LIKELY AID IN BROKEN STRATUS SHIFTING SOUTH INTO S
WI ALONG WITH THE NWLY SFC FLOW AND COLD ADVECTION. NLY SFC FLOW
WILL CONTINUE INTO TUE BUT WITH WEAKENING COLD ADVECTION. DAYTIME
HEATING AND DRIER AIR SHOULD BE ENOUGH TO SCATTER OUT THE STRATUS
DECK. HOWEVER HIGH TEMPS WILL REMAIN WELL BELOW NORMAL WITH 925 MB
TEMPS ONLY WARMING TO 5-7C.
AN UPPER LOW OVER THE WRN USA WILL THEN OPEN UP AS A SHORTWAVE
TROUGH AND MOVE TOWARD WI FOR WED. DESPITE MID LEVEL FRONTOGENESIS
OVER THE REGION...KEPT THE FCST DRY AS MUCH OF THE LOW TO MID
LEVEL WARM...MOIST ADVECTION STAYS TO THE SOUTH. THUS EXPECT MO
CLOUDY SKIES FROM MIDDLE TO HIGH CLOUDS. THE CLOUDS WILL KEEP THE
HIGH TEMPS MAINLY IN THE 50S FOR THE 2ND DAY IN A ROW.
LONG TERM...
THURSDAY THROUGH SUNDAY...FORECAST CONFIDENCE MEDIUM.
THE SRN PERIPHERY OF AN UPPER TROUGH WILL MOVE ACROSS THE NORTHERN
AND EASTERN GREAT LAKES THU-FRI. THIS IS EXPECTED TO BRING A WEAK
AND DRY BACKDOOR COLD FRONT ACROSS SRN WI ON FRI. HIGH PRESSURE
WILL THEN FOLLOW FROM THE NORTHERN GREAT LAKES TO THE EASTERN
GREAT LAKES FOR FRI-SAT. FOR SAT NT AND SUN AN UPPER TROUGH WILL
EJECT NEWD TOWARD WI FROM THE 4 CORNERS REGION ALONG WITH ITS SFC
TROUGH. A GOOD SURGE OF WARM...MOIST ADVECTION AND SHOWERS/TSTORMS
ARE EXPECTED. TEMPS WILL RETURN TO NEAR NORMAL FOR THE THU-SUN
PERIOD.
AVIATION/00Z TAFS/...
AN AREA OF SHOWERS AND THUNDERSTORMS OVER SOUTH CENTRAL WI SHOULD
EXPAND AS IT TRACKS INTO SOUTHEAST WI THROUGH 6 PM. THIS WILL BE
ABOUT A 2 HOUR PERIOD OF MODERATE TO HEAVY RAIN AND OCCASIONAL
THUNDER.
LOOK FOR A QUIET PERIOD OF WEATHER LATE THIS AFTERNOON. THERE IS ONE
MORE SMALL CHANCE FOR THUNDERSTORMS EARLY THIS EVENING... BUT THAT
CHANCE IS NOW LOOKING VERY LOW.
THE RISK FOR SEVERE WEATHER HAS DECREASED... BUT ISOLATED SEVERE
STORMS ARE STILL POSSIBLE.
LOOK FOR CLEARING SKIES OVERNIGHT. GUSTY WEST WINDS AND SCATTERED TO
BROKEN VFR CUMULUS CLOUDS EXPECTED MONDAY.
MARINE...
DENSE FOG ADVISORY WAS EXTENDED UNTIL 00Z/ 7PM THIS EVENING DUE TO
PERSISTENT SOUTHEAST WINDS AND WARM AND HUMID AIR OVER THE LAKE.
INCREASING SOUTH TO SOUTHWEST WINDS SHOULD PUSH ANY LINGERING FOG
OUT OF THE NEARSHORE WATERS THIS EVENING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...DAVIS
TONIGHT/MONDAY AND AVIATION/MARINE...MRC
MONDAY NIGHT THROUGH SUNDAY...GEHRING
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
609 PM CDT SUN MAY 17 2015
NEW INFORMATION ADDED TO UPDATE SECTION
.UPDATE...
ISSUED AT 608 PM CDT SUN MAY 17 2015
STORMS HAVE DIMINISHED IN INTENSITY AND COVERAGE THE
LAST FEW HOURS OVER THE FORECAST AREA. MESO DATA SUGGESTS THE
REGION OF POTENTIAL NEW DEVELOPMENT OF STORMS LIKELY OVER THE
NORTHWEST HALF OF THE STATE...INCLUDING PARTS OF CENTRAL AND
NORTH CENTRAL WISCONSIN WITH THE BEST SHEAR VALUES...AND STEEP
SURFACE LAPSE RATES. ANTICIPATE THE SURFACE LAPSE RATES TO BE ON
THE DECLINE THE NEXT FEW HOURS...SO THE THREAT OF STRONG TO SEVERE
STORMS SHOULD LESSON. SPIRALING BANDS OF CONVECTION OVER EASTERN
MINNESOTA AND FAR WESTERN WISCONSIN CLOSER TO THE LOW PRESSURE
AREA OVER NORTHERN MINNESOTA MAY ROTATE INTO THIS ENVIRONMENT AND
INTENSIFY OVER NORTH CENTRAL WISCONSIN THIS EVENING.
&&
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 229 PM CDT SUN MAY 17 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN OCCLUDED
LOW PRESSURE SYSTEM SPINNING OVER THE EASTERN DAKOTAS. SHORTWAVES
ARE ROTATING NORTHWARD AHEAD OF THIS OCCLUDED CYCLONE...THE
STRONGEST OF WHICH IS LOCATED OVER EASTERN IOWA. A PWAT AXIS IS
MOVING ACROSS WISCONSIN EARLY THIS AFTERNOON...WHICH COMBINED WITH
MOISTURE CONVERGENCE...IS CONTRIBUTING TO SCATTERED SHOWER
DEVELOPMENT OVER CENTRAL WISCONSIN. CLOUD COVER HAS SIGNIFICANTLY
SLOWED THE HEATING CURVE SO FAR TODAY...KEEPING ML CAPES BELOW 200
J/KG. WITH SHOWER COVERAGE EXPECT TO INCREASE THROUGH THE
AFTERNOON...IT WILL BE TOUGH TO SEE MUCH OF AN INCREASE OF
INSTABILITY. STILL THOUGH...RADAR ECHOES SUGGEST SOME THUNDERSTORMS
WILL BE POSSIBLE...AND ANY STORMS COULD BRING DOWN STRONG WINDS FROM
ALOFT. WILL HAVE TO KEEP A MENTION OF ISOLATED DAMAGING WINDS
THROUGH EARLY THIS EVENING. OTHERWISE...THE LATEST HRRR CONGEALS THE
SHOWER ACTIVITY INTO BAND AND PROGRESSES IT ACROSS THE FORECAST AREA
FOR THE REST OF THE AFTERNOON.
TONIGHT...LOW PRESSURE WILL MOVE EAST ACROSS NORTHERN
MINNESOTA...WHILE A COLD FRONT WILL PUSH EAST THROUGH ALL BUT FAR
EASTERN WISCONSIN OVERNIGHT. THOUGH SHORTWAVE ENERGY WILL BE
ROTATING NORTHEAST OVER NORTHWEST WISCONSIN THROUGH THE
EVENING...CONCERNED THAT STRONG DRYING AND INCREASING CAPPING IN THE
MID-LEVELS WILL EVEN FURTHER LIMIT THUNDERSTORM POTENTIAL FOR THE
FIRST COUPLE HOURS IN THE EVENING. WILL KEEP A MENTION OF ISOLATED
DAMAGING WINDS THROUGH 02Z IN CASE SOME THUNDERSTORMS MAKE A RUN
INTO N-C WISCONSIN FROM MINNESOTA. ONCE THE THREAT OF STORMS ENDS...MODELS
SHOW CLEARING TAKING PLACE UNTIL LOW CLOUDS FLOOD EAST BEHIND THE
COLD FRONT LATE TONIGHT. LOW TEMPS NEAR 60 OVER THE EAST...BUT
COOLING TO NEAR 50 OVER THE WEST.
MONDAY...OCCLUDED LOW PRESSURE WILL BE WEAKENING AS IT MOVES TO THE
EAST ACROSS LAKE SUPERIOR. WEST WINDS ON THE SOUTHERN FLANK OF THE
LOW WILL BE COLD ADVECTING THROUGH THE DAY...WHILE PUSHING IN WRAP
AROUND MOISTURE. SHOULD SEE AMPLE CLOUD COVER OVER CENTRAL AND
NORTH-CENTRAL WISCONSIN THROUGH THE DAY...BUT EAST-CENTRAL WISCONSIN
WILL LIKELY SEE SOME SUN IN THE MORNING BEFORE CLOUDS INCREASE IN
THE AFTERNOON. WITH THE SUNSHINE...TEMPS SHOULD WARM TO NEAR 70 IN
THE EAST...BUT ONLY INTO THE MID AND UPPER 50S OVER THE WEST.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 229 PM CDT SUN MAY 17 2015
MUCH COOLER TEMPERATURES FOR THE FIRST HALF OF THE WORK WEEK...DRY
AND MILDER CONDITIONS FOR THE LATTER HALF...AND A POSSIBLE RETURN
TO WET WEATHER LATER IN THE MEMORIAL DAY WEEKEND...ARE THE MAIN
FCST CONCERNS.
THE REMNANTS OF THE UPPER LOW WILL TRACK ACROSS NORTHERN LAKE SUPERIOR
ON MONDAY NIGHT...FOLLOWED BY A S/W TROF PASSING NORTH OF WI ON TUESDAY.
UNSEASONABLY COLD AIR (H8 TEMPS -8 TO -10 C) WILL FLOW INTO THE REGION
ON NNW WINDS...SETTING THE STAGE FOR SOME LAKE-ENHANCED SHOWERS OVER
NC WI. LOW-LEVEL TEMPS AND THICKNESSES SUPPORT A MIX THEN CHANGEOVER
TO SNOW LATE MONDAY NIGHT INTO TUESDAY MORNING...WITH LITTLE OR NO
ACCUMULATION EXPECTED. ANY LINGERING PCPN SHOULD END TUESDAY AFTERNOON
AS CANADIAN HIGH PRESSURE BUILDS INTO THE REGION.
HIGH PRESSURE WILL COVER THE AREA TUESDAY NIGHT INTO WEDNESDAY. STILL
EXPECTING FROST TUESDAY NIGHT...BUT GETTING A LITTLE CONCERNED ABOUT
THE POSSIBILITY OF THICKER HIGH LEVEL CLOUDS...DUE TO THE PRESENCE
OF A STRONG JET STREAK OVER THE REGION. RIGHT NOW...HAVE JUST
BUMPED UP CLOUD COVER A BIT OVER C/EC WI...BUT KEPT MOSTLY CLEAR
SKIES OVER NORTHERN WI. WILL CONTINUE TO CARRY WIDESPREAD FROST OR
FREEZE CONDITIONS OVER NORTHERN WI...AND PATCHY FROST OVER MOST OF
C/EC WI.
A WEAK BACK DOOR COLD FRONT WILL SAG THROUGH THE FORECAST AREA THURSDAY
INTO THURSDAY NIGHT...BUT WILL NOT HAVE ANY MOISTURE TO WORK WITH...SO
DRY WEATHER WILL PREVAIL. BEHIND THE FRONT...CANADIAN HIGH PRESSURE
WILL REESTABLISH ITSELF OVER THE WESTERN GREAT LAKES...AND IS EXPECTED
TO LINGER INTO SATURDAY. ABUNDANT SUNSHINE SHOULD BRING A RETURN TO
NEAR NORMAL TEMPERATURES FOR THE LATTER HALF OF THE WEEK.
AN UPPER TROF...LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL
IMPACT THE REGION FROM SATURDAY NIGHT INTO SUNDAY. GULF MOISTURE
IS EXPECTED TO FLOW INTO THE REGION AHEAD OF THE FRONT...WITH
PRECIPITABLE WATER VALUES REACHING 1.00-1.25 INCHES. HAVE RAMPED
POPS UP TO LIKELY FOR SUNDAY. THE ECMWF PULLS MOST OF THE PCPN OUT
OF THE REGION SUNDAY EVG...WHILE THE GFS HANGS ONTO SIGNIFICANT
QPF INTO MEMORIAL DAY...SO FCST CONFIDENCE WANES BEYOND SUNDAY.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 552 PM CDT SUN MAY 17 2015
MARGINAL TO STRONG SHEAR ALONG WITH MARGINAL INSTABILITY WILL
CONTINUE TO PRODUCE AN ENVIRONMENT FOR THE DEVELOPMENT OF STORMS
THIS SUNDAY EVENING. PRIMARY FOCUS OF STRONGER STORMS THIS
EVENING APPEAR TO BE OVER THE NORTHWEST HALF THE STATE INCLUDING
PARTS OF CENTRAL AND NORTH CENTRAL WISCONSIN. IFR CONDITIONS WITH
LIFR CIGS WILL LINGER ALONG THE LAKE MICHIGAN SHORE LINE.
SOUTHWEST WINDS WILL IMPROVE CONDITIONS OVERNIGHT. OTHERWISE AFTER
A PERIOD OF VFR CONDITIONS OVERNIGHT...MVFR CIGS WILL FILTER INTO
THE STATE FROM NORTHWEST TO SOUTHEAST THROUGH MONDAY WITH BLUSTERY
WEST TO NORTHWEST WINDS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE.........TDH
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
337 PM CDT SAT MAY 16 2015
.SHORT TERM...
TONIGHT THROUGH SUNDAY AFTERNOON...FORECAST CONFIDENCE MEDIUM.
WIDELY SCATTERED THUNDERSTORMS PERSIST THROUGH LATE AFTERNOON. THESE
ARE BEING TRIGGERED BY A WEAK MID LEVEL SHORTWAVE APPROACHING FROM
IA/IL. MODEL SOUNDINGS AND RAP SPC MESOSCALE ANALYSIS ARE SHOWING
TALL SKINNY CAPE VALUES OF 1000 TO 2000 J/KG INLAND FROM THE
LAKESHORE THIS AFTERNOON. THERE IS NOT MUCH SHEAR... SO ONLY BRIEF
SMALL HAIL WOULD BE POSSIBLE IN ANY STRONGER STORMS. THE MAIN THREAT
WILL BE BRIEF HEAVY RAIN SINCE PRECIPITABLE WATER VALUES ARE AROUND
1.3 INCHES TODAY.
THESE THUNDERSTORMS WILL DIMINISH AFTER SUNSET THIS EVENING. LIGHT
WINDS AND SMALL DEWPOINT DEPRESSIONS WILL LEAD TO PATCHY FOG AND LOW
CLOUDS ACROSS SOUTHERN WI OVERNIGHT. THERE IS A CHANCE THAT MARINE
FOG WILL SPREAD INLAND ONCE AGAIN. THE CLOUDS WILL LIKELY LINGER
INTO THE MID SUNDAY MORNING HOURS.
SURFACE LOW PRESSURE OVER THE DAKOTAS WILL TRACK INTO MINNESOTA
TONIGHT AND STALL THROUGH SUNDAY AS IT OCCLUDES. THE 850 MB WARM
CONVEYOR BELT... OR WARM MOIST AIR TRANSPORT... WILL LIFT THROUGH
SOUTHERN WI SUNDAY MORNING INTO THE EARLY AFTERNOON. THIS WILL BRING
A BAND OF NUMEROUS SHOWERS AND THUNDERSTORMS THAT SHOULD MARCH
NORTHEAST ACROSS SOUTH CENTRAL AND SOUTHEAST WI. THERE IS SOME
CONCERN THAT AN EMBEDDED THUNDERSTORM COULD BECOME SEVERE DURING THE
AFTERNOON AS THE ATMOSPHERE BECOMES LESS STABLE. MODELS ARE HINTING
AT SOUTHEAST WI AND LAKE MICHIGAN HAVING THE GREATEST THREAT FOR
ENHANCED THUNDERSTORMS ON THE BACK EDGE OF THIS FIRST ROUND.
TEMPERATURES WILL RISE INTO THE UPPER 70S... SIMILAR TO TODAY.
LAKESHORE TEMPS WILL BE A LITTLE COOLER THAN INLAND GIVEN A SLIGHT
EASTERLY COMPONENT. WINDS WILL BE STRONG OUT OF THE SOUTH DUE TO A
TIGHT PRESSURE GRADIENT WITH THE APPROACHING SURFACE LOW.
LATE SUNDAY AFTERNOON THROUGH TUESDAY...FORECAST CONFIDENCE
MEDIUM.
THE OCCLUDED LOW OVER NW MN WILL WEAKEN TO A BROAD W-E SFC TROUGH
STARTING LATE SUNDAY NIGHT AND THROUGH MONDAY AS IT MOVES ACROSS
LAKE SUPERIOR AND INTO CANADA. BEFORE IT WEAKENS...THE PASSAGE OF
A TRAILING UPPER TROUGH AXIS AND A PREFRONTAL SFC TROUGH WILL
LIKELY INITIATE A NEW ROUND OF SCATTERED CONVECTION LATE SUNDAY
AFTERNOON AND THROUGH THE EVENING. THE NAM AND SOME MESOMODELS
ARE SHOWING WHAT WILL LIKELY BE DISCRETE SUPERCELLS DEVELOPING
FROM THE MS RIVER EWD. A 60-65 KT 500 MB JET STREAK WILL
ACCOMPANY THE UPPER WAVE...SUPPORTING 0-6 KM BULK SHEAR OF 50
KTS AND A SUPERCELL POTENTIAL WITH MLCAPE VALUES UP TO 1500 J/KG
OVER SOUTH CENTRAL WI. A TORNADO RISK WILL BE PRESENT DUE TO
0-1 KM SRH OF 150-200 M2/S2 AND 0-1 KM BULK SHEAR RISING TO 25
KTS. LCL HEIGHTS WILL ALSO BE AT OR BELOW 1 KM WITH THE LFC ONLY
SLIGHTLY HIGHER. SPC HAS UPGRADED TO AN ENHANCED RISK OF SEVERE
TSTORMS OVER MUCH OF WESTERN AND CENTRAL WI...MENTIONING THE
POSSIBILITY OF STRONG TORNADOES. CAPE VALUES WILL REMAIN BELOW
1000 J/KG OVER ERN WI AND THE STORMS MAY NOT ARRIVE UNTIL THE
MIDDLE TO LATE EVENING...THUS THE SLIGHT RISK THERE. HOWEVER SHEAR
VALUES DO BECOME STRONG AS WELL.
THE ACTUAL COLD FRONT WILL GRADUAL MOVE ACROSS SRN WI ON
MONDAY...THUS 70 DEGREE HIGHS ARE EXPECTED. NWLY FLOW AND COLD
ADVECTION WILL THEN PREVAIL FOR MONDAY NIGHT AND TUESDAY. SRN WI
APPEARS TO BE FAR ENOUGH SOUTH TO AVOID THE BROKEN STRATUS ON
MONDAY BUT SOME STRATUS WILL BE POSSIBLE MONDAY NIGHT INTO
TUESDAY. A CANADIAN AIRMASS AND LINGERING CLOUDS INTO TUE
AFTERNOON WILL KEEP HIGH TEMPS ONLY IN THE 50S.
.LONG TERM...
TUESDAY NIGHT THROUGH SATURDAY...FORECAST CONFIDENCE MEDIUM.
A LARGE SFC HIGH WILL EXTEND FROM THE GREAT PLAINS TOWARD THE OHIO
RIVER VALLEY FOR THIS PERIOD. A RELATIVELY WEAK WNWLY FLOW ALOFT
WILL PREVAIL WITH BELOW NORMAL TEMPS EXPECTED IN THE BEGINNING OF
THE PERIOD BUT QUICKLY REBOUND TO SEASONAL NORMALS. NO PCPN IS
EXPECTED.
&&
.AVIATION/00Z TAFS/...COMING SOON.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...DENSE FOG ADVISORY UNTIL 10 AM CDT SUNDAY FOR LMZ643>646.
&&
$$
TONIGHT/SUNDAY AND AVIATION/MARINE...MRC
SUNDAY NIGHT THROUGH SATURDAY...GEHRING
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1129 PM MDT SUN MAY 17 2015
.SHORT TERM...(TONIGHT THROUGH MONDAY NIGHT)
ISSUED AT 331 PM MDT SUN MAY 17 2015
IN SPITE OF BUILDING HIGH PRESSURE OVER UTAH AND WARMING TEMPS
ALOFT...AFTERNOON CAPE VALUES OF 250-500 J/KG SUGGEST CONVECTIVE
SHOWERS WITH SOME THUNDERSTORMS. MOISTURE TRANSPORT DOES EXIST
FROM THE UINTA MOUNTAINS TOWARD VAIL AND INDEPENDENCE PASS
REGION...AND SHOWERS/STORMS WILL BE CONCENTRATED ACROSS THIS AREA.
CONVECTIVE POTENTIAL EXIST ELSEWHERE BUT NOT AS NUMEROUS OVER SW
COLORADO...AND MOSTLY DRY OVER SE UTAH.
CONVECTIVE POTENTIAL MOSTLY DIMINISHES WITH SUNSET. NOT SO SURE
THIS WILL BE THE CASE ACROSS PARTS OF ERN UTAH AS MOISTURE
TRANSPORT INCREASES OVERNIGHT...THE HRRR SHOW CONVECTIVE SHOWERS
PERSISTING PAST MIDNIGHT AND TRACKING OVER THE UINTA
BASIN/MOUNTAINS. BY DAYBREAK...HIGH CLOUDS WILL BE SPREADING FROM
THE SOUTH AS THE NEXT CALIFORNIA UPPER LOW ADVECTS MOISTURE
TOWARDS THE FOUR CORNERS REGION.
THE PACIFIC WAVE TRAIN CONTINUES MONDAY AS THE NEXT STORM SYSTEM
MOVES SLOWLY ONSHORE...ITS CENTER SETTLING OVER CALIFORNIA/S SAN
JOAQUIN VALLEY LATE IN THE AFTERNOON. SOUTHERLY FLOW AHEAD OF THE
TROUGH WILL CAUSE MOISTURE LEVELS TO RISE ONCE AGAIN AS GULF
MOISTURE IS TAPPED. GFS AND NAM BOTH INDICATED PRECIPITABLE WATER
VALUES RISING TO NEAR 0.6 OF AN INCH. MEANWHILE...AN 110 KT JET
ROTATES THROUGH THE BASE OF THE TROUGH GIVING IT A SLIGHTLY
NEGATIVE TILT. THE NOSE OF THE JET PUSHES TOWARD THE FOUR CORNERS
WHICH WILL PROVIDE CONSIDERABLE DIVERGENCE TO ADD TO THE DIFFLUENT
FLOW ALOFT. THE DYNAMIC LIFT JUST DESCRIBED COMBINED WITH DAYTIME
HEATING WILL GENERATE SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS FAVORING THE MOUNTAINS. AS MENTIONED IN THE PREVIOUS
DISCUSSION...ARRIVING MOISTURE WILL BE HIGH BASED ACCORDING TO
AREA TIME SECTIONS SO EXPECT MAIN STORM THREAT...ASIDE FROM
LIGHTNING...WILL BE STRONG AND GUSTY OUTFLOW WINDS. WAA ADVECTION
WILL CAUSE TEMPERATURES TO CLIMB CLOSER TO SEASONAL NORMS...
THOUGH EXPECT CLOUDS AND SHOWERS WILL LIMIT HIGHS. THEREFORE...
NUDGED MONDAY/S HIGHS TOWARD COOLER MAV GUIDANCE.
MONDAY NIGHT WILL REMAIN ACTIVE AS THE PACIFIC SYSTEM MOVES OVER
SOUTHERN NEVADA DURING THE NIGHT. DIFFLUENT/DIVERGENT FORCING
REMAINS IN PLACE WHILE MOISTURE CONTINUES TO STREAM INTO THE AREA
FROM THE SOUTH. AS A RESULT...WILL CONTINUE WITH LIKELY POPS IN
THE MOUNTAINS WITH CHANCE POPS ACROSS THE VALLEYS. COLDER AIR
BEGINS TO ADVECT OVER THE REGION DURING THE NIGHT CAUSING SNOW
LEVELS TO LOWER TO AROUND 9000 TO 9500 FEET. EXPECT ACCUMULATING
SNOW FOR AREAS ABOVE 10000 FEET WITH AMOUNTS OF UP TO 8 INCHES
POSSIBLE ABOVE THE TIMBERLINE. MODELS SUGGEST AMOUNTS OF 12 INCHES
OR MORE BUT APPEARS CONVECTIVE PARAMETERIZATION MAY BE A BIT
OVERDONE AS LAPSE RATES ONLY MODERATELY UNSTABLE. IMPACTS TO
ROADWAYS OVER THE HIGH PASSES PROBABLY NEGLIGIBLE WITH MOST SNOW
MELTING ON CONTACT SO WILL HOLD OFF ISSUING HILITES. CLOUDS...
SHOWERS AND WAA WILL YIELD MILDER OVERNIGHT LOWS AS PREVIOUSLY
FORECAST.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 331 PM MDT SUN MAY 17 2015
COOL AND UNSETTLED CONDITIONS WILL CONTINUE TUESDAY AS THE
PACIFIC STORM MOVES OVER THE REGION. SNOW LEVELS WILL RISE WITH
DAYTIME WARMING...ESPECIALLY SOUTH...WHICH WILL INHIBIT ANY
ADDITIONAL ACCUMULATIONS BELOW 10000 FEET. CONDITIONS IMPROVE
TUESDAY NIGHT AS A TRANSIENT SHORTWAVE RIDGE BUILDS OVER THE AREA.
ANOTHER LOW DEVELOPS OVER THE EASTERN PACIFIC AT MIDWEEK BUT STAYS
QUASI-STATIONARY UNTIL THURSDAY NIGHT. A DRIER SOUTHWEST FLOW
WILL MOVE OVER THE FORECAST AREA AHEAD OF THIS SYSTEM LIMITING
MOIST CONVECTION TO THE MOUNTAIN AREAS DURING THE AFTERNOON AND
EVENING WEDNESDAY AND THURSDAY. TEMPERATURES WILL RECOVER DURING
THIS PERIOD REACHING NEAR NORMAL LEVELS THURSDAY AFTERNOON.
THE PACIFIC SYSTEM THEN FOLLOWS THE WELL BEATEN PATH PREVIOUS
STORMS HAVE TAKEN OVER THE PAST COUPLE OF WEEKS...TRACKING OVER
EASTERN UTAH AND WESTERN COLORADO FRIDAY AND SATURDAY.
CONSEQUENTLY...LOOK FOR AN UPTICK IN SHOWER AND THUNDERSTORM
ACTIVITY ONCE AGAIN ALONG WITH COOLER THAN NORMAL TEMPERATURES.
CONDITIONS ON SUNDAY LESS CERTAIN AS LATEST ECMWF DRIVES A
SHORTWAVE TROUGH ACROSS THE REGION FROM THE NORTHWEST WHILE GFS
FAVORS A TRANSITORY RIDGE. BOTH SOLUTIONS POINT TO A CONTINUATION
OF UNSETTLED CONDITIONS AS MOISTURE WILL LINGER IN EITHER CASE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1123 PM MDT SUN MAY 17 2015
A FEW SHOWERS WILL CONTINUE FOR THE NEXT SEVERAL HOURS ACROSS THE
NORTH BEFORE DIMINISHING OVERNIGHT. VFR CONDITIONS WILL CONTINUE
THROUGH THE MORNING HOURS ON MONDAY. SHOWERS AND THUNDERSTORMS
WILL INCREASE LATE MONDAY AFTERNOON AND INCREASE IN COVERAGE BY
MONDAY EVENING. HAVE INCREASED POPS AT TAF SITES WITH TEMPO/SHOWERS
WORDING WITH CATEGORICAL PRECIPITATION OVER MOUNTAIN TAF SITES AT
ASE AND TEX DEVELOPING BY 19/02Z. EXPECT VISIBILITY AND CEILINGS
TO LOWER IN THE SHOWERS AND THUNDERSTORMS WITH MOUNTAIN BECOMING
OBSCURED. SNOW LEVELS ARE EXPECTED TO BE AROUND 10000 FEET BUT LOWERING
TO 9000 FEET IN HEAVIER SHOWERS.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...PF/NL
LONG TERM...NL
AVIATION...MPM
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1145 PM CDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 852 PM CDT SUN MAY 17 2015
OVERNIGHT FORECAST DOING WELL. SOUTHERLY WINDS MAINTAINING SOME
WARM TEMPS FOR THE OVERNIGHT...AND MAJORITY OF PRECIP THREAT ALONG
AND SOUTH OF A LINE FROM TAYLORVILLE TO CHAMPAIGN. SHORT TERM
MODELS PREV BLEW SOME CONVECTION INTO SOUTHEASTERN IL WORKING OFF
OF OUTFLOW FROM ACTIVITY IN MO. HOWEVER, ATMOSPHERE HAVING
DIFFICULT TIME FOCUSING ANY LIFT, PARTICULARLY WITH THE LOSS OF
THE DIURNAL COMPONENT TO THE INSTABILITY. SHOWERS SO FAR HAVE
REMAINED LIMITED AND THE BULK OF THE THUNDER FURTHER TO THE SOUTH.
ISO TS POSSIBLE IN THE FAR SE...BUT NOT WIDESPREAD. NOT MUCH IN
THE WAY OF UPDATES ANTICIPATED AT THIS TIME.
&&
.SHORT TERM...(TONIGHT)
ISSUED AT 256 PM CDT SUN MAY 17 2015
POTENTIAL FOR SEVERE WEATHER THIS AFTERNOON/EVENING IS STILL BEING
MONITORED...HOWEVER IT IS BEGINNING TO LOOK LIKE ANY SEVERE WILL BE
ISOLATED AT BEST. 18Z KILX UPPER AIR SOUNDING SHOWS SBCAPE OF
2000J/KG AND 0-6KM BULK SHEAR OF 35KT: HOWEVER, A WARM LAYER AT
AROUND 900MB IS KEEPING THE ATMOSPHERE MOSTLY CAPPED. REGIONAL
MESOSCALE ANALYSIS INDICATES A POCKET OF GREATER INSTABILITY ACROSS
NORTH-CENTRAL ILLINOIS FROM PEORIA/BLOOMINGTON NORTHWARD...MAKING
THIS THE PRIMARY SPOT FOR POTENTIAL CONVECTIVE DEVELOPMENT OVER THE
NEXT COUPLE OF HOURS. HRRR SHOWS THIS SCENARIO UNFOLDING...WITH
SCATTERED STORMS LIFTING NORTHWARD INTO NORTHERN ILLINOIS/SOUTHERN
WISCONSIN LATER THIS AFTERNOON. FURTHER SOUTH...THE UPSTREAM
AIRMASS ACROSS MISSOURI/SOUTHWEST ILLINOIS REMAINS STABLE AND CAPPED
IN THE WAKE OF A MORNING OUTFLOW BOUNDARY THAT HAS PUSHED WELL TO
THE EAST INTO WESTERN SECTIONS OF KENTUCKY AND TENNESSEE. END
RESULT WILL LIKELY BE ONLY WIDELY SCATTERED STORMS DEVELOPING ALONG
THE I-55 CORRIDOR AFTER 21Z...WITH MINIMAL SEVERE WEATHER THREAT.
HIGH-RES MODELS CONTINUE TO SUGGEST CONVECTION WILL RE-DEVELOP OVER
SOUTHEAST MISSOURI/ARKANSAS THIS EVENING...THEN LIFT INTO SOUTHEAST
ILLINOIS TONIGHT. PARTIAL CLEARING HAS OCCURRED ACROSS THIS
AREA...HOWEVER AIRMASS REMAINS STABLE BEHIND THE PREVIOUS OUTFLOW
BOUNDARY...SO AM SKEPTICAL OF THIS SOLUTION. WILL CONTINUE TO
MONITOR SOUTHEAST MISSOURI FOR DEVELOPMENT OVER THE NEXT SEVERAL
HOURS. AT THIS TIME...WILL CARRY ONLY SLIGHT OR LOW CHANCE POPS
WEST OF THE I-57 CORRIDOR THROUGH THE EVENING HOURS...WITH DRY
CONDITIONS OVERNIGHT. FURTHER EAST...WILL GO WITH HIGHER POPS IN
THE HIGHER DEWPOINT/MORE UNSTABLE AIRMASS ALONG/EAST OF I-57.
.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 256 PM CDT SUN MAY 17 2015
COLD FRONT WILL PASS THROUGH CENTRAL ILLINOIS ON MONDAY...DROPPING
SOUTH OF THE I-70 CORRIDOR BY LATE AFTERNOON. SCATTERED SHOWERS AND
THUNDERSTORMS MAY DEVELOP AHEAD OF THE FRONT...HOWEVER AREAL
COVERAGE WILL BE GREATEST FURTHER EAST ACROSS THE OHIO RIVER VALLEY.
WILL MAINTAIN CHANCE POPS ALONG/EAST OF A DANVILLE TO SHELBYVILLE
LINE THROUGHOUT THE DAY UNTIL THE BOUNDARY EXITS. HIGH PRESSURE
WILL TAKE CONTROL OF THE WEATHER BEHIND THE DEPARTING
FRONT...PROVIDING COOL/DRY WEATHER FOR TUESDAY. RESULTING HIGH
TEMPERATURES WILL REMAIN IN THE LOWER TO MIDDLE 60S...WHILE
OVERNIGHT LOWS DIP INTO THE 40S.
PIECE OF ENERGY IS EXPECTED TO EJECT FROM WESTERN CONUS UPPER LOW BY
MID-WEEK...BRINGING CLOUDS AND PERHAPS A FEW SHOWERS INTO THE AREA
ON WEDNESDAY. MODELS DEPICT A WEAKENING WAVE COMING INTO A VERY DRY
AIRMASS...SO THINK ANY RAINFALL WILL BE QUITE LIGHT. HAVE CUT BACK
ON POPS...FEATURING LIKELY ACROSS THE FAR SOUTHWEST CWA AROUND
JACKSONVILLE TAPERING DOWN TO JUST SLIGHT ALONG THE INDIANA BORDER.
ONCE THIS WAVE DEPARTS...COOL/DRY WEATHER WILL RETURN FOR THURSDAY
AND FRIDAY.
MAIN UPPER LOW WILL GRADUALLY LIFT INTO THE PLAINS LATE IN THE
PERIOD...BRINGING THE NEXT SIGNIFICANT CHANCE FOR RAIN BY LATE IN
THE WEEKEND. WHILE MODEL DIFFERENCES STILL EXIST...GFS/ECMWF
CONSENSUS POINTS TO THE SUNDAY/MONDAY TIME FRAME AS THE PRIMARY TIME
FOR SHOWERS AND THUNDERSTORMS. HAVE THEREFORE KEPT RAIN CHANCES OUT
OF THE FORECAST FOR SATURDAY...THEN HAVE HIT POPS HARD FOR SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1136 PM CDT SUN MAY 17 2015
SOME MINOR ADJUSTMENTS TO INCLUDE A SCT LAYER AT 120-150 THIS
EVENING WITH AUGMENTED SITES PICKING UP ON THE MID LEVEL MOISTURE
STREAMING IN. SOME PRECIP WELL TO THE WEST KICKING UP ON OUTFLOW
BOUNDARY FROM EARLIER STORMS IN SOUTH CENTRAL IOWA. MODELS NOT
PICKING UP ON IT AT THIS POINT BUT SEE NO REASON TO INCLUDE IT AT
THIS EARLY STAGE...WILL WATCH PIA FOR POTENTIAL IF IT HOLDS
TOGETHER. FRONT MOVING THROUGH WILL BRING THE WINDS AROUND TO MORE
WESTERLY MID MORNING FOR PIA... MORE MID DAY FOR REMAINING TAF
SITES. MOSTLY A CIRRUS KIND OF DAY, THOUGH FORECAST SOUNDINGS AND
CU RULE POINT TO A CU FIELD ROUGHLY ALONG AND SOUTHEAST OF A LINE
FROM SPI TO BMI...DENSER TO THE SOUTH AND EAST AHEAD OF THE
BOUNDARY.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HJS
SHORT TERM...BARNES
LONG TERM...BARNES
AVIATION...HJS
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
400 AM EDT MON MAY 18 2015
.SYNOPSIS...
ISSUED AT 358 AM EDT MON MAY 18 2015
A COLD FRONT WILL APPROACH THE REGION THIS AFTERNOON. SCATTERED
SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG AND JUST IN ADVANCE OF
THE FRONT THIS AFTERNOON INTO EARLY THIS EVENING BEFORE
DIMINISHING. THE PASSAGE OF THIS COLD FRONT WILL RESULT IN MUCH
COOLER CONDITIONS THROUGH THE MIDDLE PORTIONS OF THE WEEK. HIGH
TEMPERATURES THIS AFTERNOON WILL RANGE FROM THE UPPER 70S TO LOWER
80S. LOW TEMPERATURES TONIGHT WILL DROP BACK INTO UPPER 40S TO
LOWER 50S. HIGH TEMPERATURES ON TUESDAY AND WEDNESDAY WILL RANGE
FROM THE MID 50S TO LOWER 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EDT MON MAY 18 2015
DRIER MID LEVEL AIR HAS ADVECTED INTO MOST OF THE FORECAST AREA THIS
MORNING. DEEPEST MOISTURE THROUGH THE MORNING HOURS IS EXPECTED TO
RESIDE ACROSS APPROXIMATELY THE SOUTHEAST THIRD OF THE AREA WHERE
SOME UPSWING IN 850-700 HPA MOISTURE TRANSPORT IS EXPECTED OVER THE
NEXT SEVERAL HOURS. 3-6 HOUR RAP PROGS DO INDICATE ABOUT 250-500
J/KG OF INSTABILITY LINGERING ACROSS THESE LOCATIONS EXPERIENCING
STRONGER MOISTURE TRANSPORT THIS MORNING...SO HAVE CONTINUED TO
CONCENTRATE LOW CHANCE POPS ACROSS THE SOUTHEAST THIS MORNING AS
ADDITIONAL WEAK SHORT WAVES TRACK NORTHEAST THROUGH THE OHIO VALLEY
IN ASSOCIATION WITH SOUTHERN STREAM.
ATTENTION FOR THE REMAINDER OF THE DAY WILL CENTER ON EVOLUTION OF
SFC COLD FRONTAL BOUNDARY AND POTENTIAL OF ANY ADDITIONAL SCATTERED
CONVECTION THIS AFTERNOON/EARLY EVENING. INSPECTION OF SHORT TERM
TRENDS SUGGESTS NAM MAY BE JUST A BIT SLOW WITH COLD FRONT ACROSS
THE MID MS RVR VALLEY...AND THE NAM CONTINUES TO BE SOMEWHAT OF A
SLOW OUTLIER THROUGH THE NEXT 24 HOURS WITH THE FRONTAL PROGRESSION.
EVEN WITH A PROGRESSION SOMEWHAT FASTER THAN THE NAM...PREFRONTAL
WARMING SHOULD SUPPORT HIGHS IN THE LOWER 80S FOR MOST LOCATIONS
THIS AFTERNOON. OUTSIDE OF FRONTAL CONVERGENCE...MID/UPPER LEVEL
FORCING IS EXPECTED TO BE QUITE WEAK...ALTHOUGH WATER VAPOR EARLY
THIS MORNING DOES DEPICT SOME INTEGRITY TO AN UPSTREAM WAVE LIFTING
NORTHEAST OUT OF OKLAHOMA/SOUTHEAST MISSOURI. THIS FEATURE SHOULD
RAPIDLY EJECT NORTHEAST...BUT BECOME LESS POTENT AS IT BECOMES MORE
HIGHLY SHEARED ACROSS THE OHIO VALLEY/SOUTHERN GREAT LAKES REGION
LATER THIS AFTERNOON/THIS EVENING.
SOME OF THE NAM AND HIRES OUTPUT DOES INDICATE A NARROW ZONE OF
PREFRONTAL CONFLUENCE WITH SOME SUBSTANTIAL MOISTURE POOLING. HAVE
SOME SUSPICION THE SLOWER NAM OUTLIER MAY BE A BIT AGGRESSIVE IN
TERMS OF THE MAGNITUDE OF THIS MOISTURE POOLING AND HAVE GENERALLY
TRENDED AWAY FROM THE INSTABILITY MAGNITUDES ADVERTISED BY THE NAM
ALONG THIS PREFRONTAL CORRIDOR. HAVE MAINTAINED LOW TO MID CHANCE
TSRA FOR TODAY GIVEN AT LEAST SOME WEAK MID/UPPER FORCING LIFTING
INTO THE AREA WITH AFOREMENTIONED OK/MO VORT...ALTHOUGH OUTSIDE OF
ANY AREAS OF PREFRONTAL MOISTURE POOLING...LOW LEVELS MAY MIX OUT
ENOUGH TO TEMPER INSTABILITY QUITE A BIT BY LATER THIS AFTERNOON. IF
SCATTERED CONVECTION IS ABLE TO DEVELOP THERE MAY BE TWO PRIMARY
CORRIDORS FOR INITIATION...ONE ALONG ANY WEAK PREFRONTAL CONVERGENCE
ZONE...AND THEN ALONG THE ACTUAL FRONTAL BOUNDARY. SEVERE STORMS ARE
NOT EXPECTED IN TRENDING TOWARD NON-NAM GUIDANCE FOR THERMAL
PROFILES...AND ALSO GIVEN MORE OF THE SUBSTANTIAL DEEP LAYER SHEAR
WILL BE POST-FRONTAL.
SOME ISOLATED CONVECTION MAY LINGER INTO THE EVENING ACROSS
SOUTHEAST HALF OF THE AREA...WITH MAIN STORY THROUGH THE REMAINDER
OF THE NIGHT CENTERING ON THE APPROACH OF A MUCH COOLER AND LESS
HUMID AIR MASS. SOME COLD ADVECTION STRATOCU MAY WORK INTO FAR
NORTHERN LOCATIONS OVERNIGHT...BUT OTHERWISE MOST LOCATIONS WILL
EXPERIENCE CLEARING SKIES IN THE EVENING.
&&
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 358 AM EDT MON MAY 18 2015
TRANQUIL WEATHER ANTICIPATED FOR MUCH OF THIS LONG TERM PERIOD.
SPLIT FLOW OVER WESTERN NOAM WITH A HIGHLY AMPLIFIED AND ENDURING
NORTHERN STREAM PATTERN ACROSS CANADA WILL LEAVE THE GREAT LAKES IN
A REGION OF STRONG CONFLUENCE AND GENERAL SUBSIDENCE FOR MOST OF
THIS WEEK. WILL ALSO BE MUCH COOLER BEHIND TODAY`S COLD FRONT WITH
PERSISTENT N/NW FLOW MAINTAINING AN EFFICIENT FEED OF CANADIAN AIR
INTO OUR REGION. EXPECT TEMPS ROUGHLY 10-15 DEGREES BELOW NORMAL
DURING THE MIDWEEK PERIOD. TUESDAY NIGHT WILL BE THE COLDEST PERIOD
WITH NUMEROUS SOURCES OF RAW AND STATISTICAL GUIDANCE SUGGESTING MID
30S IN OUR NORTHERN COUNTIES...WITH LOWER 40S IN OUR SOUTH. SOME
CONCERN FOR PATCHY FROST...ESPECIALLY IN OUR MICHIGAN COUNTIES AWAY
FROM THE LAKE. HOWEVER...HIGH BASED CLOUDS WILL BE INCREASING BY
WEDNESDAY MORNING AND MODELS SHOW ENOUGH OF A SURFACE PRESSURE
GRADIENT TO KEEP WINDS IN THE 5-10 MPH RANGE. GIVEN THESE CONCERNS
AND MARGINAL TEMPS WILL HOLD OFF ON MENTIONING ANY FROST IN THE
FORECAST AT THIS POINT AND CONTINUE TO MONITOR.
ONE WEAK SOUTHERN STREAM WAVE DOES EJECT OUT OF THE FOUR CORNERS AND
ATTEMPT TO PHASE WITH SUBTLE NORTHERN STREAM VORT MAX AS IT CROSSES
OUR AREA LATE WEDNESDAY. DEGREE OF DRY AND STABLE LOWER LEVELS IS
CONCERNING BUT FAVORABLE 300MB JET PLACEMENT AND SOME MODEST
CVA/HEIGHT FALLS COULD GENERATE A FEW LIGHT RAIN SHOWERS. NO MAJOR
QUALMS WITH INHERITED LOW CHANCE POPS BUT DID ADJUST THE TIMING UP A
LITTLE BIT BASED ON LATEST NAM AND ECMWF SOLUTIONS. NEXT CHANCE OF
RAIN THEREAFTER WILL NOT BE UNTIL SUNDAY WHEN SOUTHWEST FLOW FINALLY
RETURNS AHEAD OF NEXT WESTERN CONUS TROUGH EJECTING NORTHEAST. THIS
PATTERN SHIFT WILL ALSO SIGNAL THE RETURN OF WARMER AND MORE HUMID
CONDITIONS FOR AT LEAST THE LATTER HALF OF THE HOLIDAY WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 122 AM EDT MON MAY 18 2015
MID LEVEL DRY SLOT HAS OVERSPREAD THE AREA WITH THE CHANCES OF
CONVECTION OVERNIGHT HAVING DIMINISHED SIGNIFICANTLY. ANOTHER WEAK
SHORT WAVE KICKING OUT OF SOUTHERN INDIANA MAY ALLOW FOR SOME
SCATTERED SHOWERS TO LIFT BACK INTO NORTHEAST INDIANA THROUGH
EARLY MONDAY MORNING...BUT BETTER CHANCES APPEAR TO BE SOUTHEAST OF
FWA. MVFR CIGS OF 2-3K FT ARE POSSIBLE AT KFWA THROUGH AROUND
12Z...WITH GENERALLY VFR CONDITIONS OTHERWISE. A COLD FRONT
TRACKING ACROSS THE AREA MONDAY AFTERNOON MAY ALLOW FOR ISOLD-SCT
CONVECTION TO DEVELOP BUT INSTABILITY OF ANY CONSEQUENCE SHOULD BE
LIMITED TO A FAIRLY NARROW ZONE ALONG AND IMMEDIATELY AHEAD OF THE
FRONT. WITH OVERALL MID/UPPER FORCING ON THE WEAK SIDE...HAVE
MAINTAINED VCTS MENTION AT KFWA DUE TO LOW CONFIDENCE OF THUNDER
OCCURRENCE AT TERMINALS. SOUTHWEST WINDS IN ADVANCE OF THE FRONT
SHOULD BECOME SOMEWHAT GUSTY INTO THE 18-23 KNOT RANGE THIS
AFTERNOON...WITH WINDS SHIFTING TO THE WEST BEHIND THE FRONT LATE
MONDAY AFTERNOON AT KSBN...AND EARLY MONDAY EVENING AT KFWA.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...MARSILI
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS JACKSON KY
434 AM EDT MON MAY 18 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON MAY 18 2015
03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER
MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE
CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL
THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT
UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS
CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE
THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY
MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN
KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS
ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED
ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST
FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY.
THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND
17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT
LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN
PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE
ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA
SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE
MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE
THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED
CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE
THIS AFTERNOON.
ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES
OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND
CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID
KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK
THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER
AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY
SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 434 AM EDT MON MAY 18 2015
SURFACE HIGH PRESSURE RIDGING SE FROM THE NORTH CENTRAL CONUS
WILL PROVIDE DRY WEATHER AT THE START OF THE PERIOD. A PIECE OF AN
UPPER LOW CURRENTLY OVER CA WILL MAKE ITS WAY EASTWARD ACROSS THE
CONUS AT MIDWEEK...AND AS ANOTHER UPPER LOW DROPS SE TOWARD NEW
ENGLAND...THE TWO WILL COMBINE TO BRING AN AMPLIFYING TROUGH TO
THE EASTERN CONUS. AS THE WEAK UPPER LEVEL SYSTEM MOVES IN FROM
THE WEST...THE ECMWF IS MORE ACTIVE WITH THE SYSTEM...AND IT SHOWS
A WEAKENING SURFACE LOW ASSOCIATED WITH IT. THIS BRINGS LIGHT
PRECIP TO OUR LOCAL AREA IN THE WEDNESDAY NIGHT/THURSDAY TIME
FRAME. THE GFS IS WEAKER WITH THE SYSTEM AND ONLY BRINGS CLOUDS.
HAVE OPTED TO USE A MINIMAL 20 PERCENT POP AT THIS POINT.
ONCE THIS SYSTEM MOVES TO OUR EAST BY THURSDAY NIGHT...MODELS AGREE
ON A SURFACE HIGH PRESSURE SYSTEM BUILDING IN FROM THE NW WITH A
REINFORCING PUSH OF DRY AIR. THIS SHOULD HOLD INTO THE WEEKEND.
LATE IN THE WEEKEND MOISTURE SHOULD BE ON THE INCREASE AGAIN AS
THE HIGH MOVES OFF THE EAST COAST AND LOW PRESSURE DEVELOPS OVER
THE PLAINS...TURNING OUR LOW LEVEL FLOW TO THE SOUTH. HAVE
INCLUDED LOW POPS ON SUNDAY...BUT THE BETTER CHANCE OF PRECIP WILL
BE TO OUR WEST.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 135 AM EDT MON MAY 18 2015
TAFS TONIGHT WILL START OFF VFR WITH SOME MVFR POSSIBLE OVERNIGHT
AND EARLY TUESDAY MORNING. THE MVFR WILL BE WITH FOG POTENTIAL AND
DID STAY CLOSE TO PREVIOUS TAF AT THIS TIME. THE UNCERTAINTY WITH
THIS REMAINS TO SEE HOW CLOUDS COULD WANE THE DEVELOPMENT. THE
FOG WILL HAVE THE BEST POTENTIAL IN THE RIVER VALLEYS AND
LOCATIONS THAT RECEIVED RAIN TODAY. SOME SHOWERS AND
THUNDERSTORMS SOUTH ACROSS THE TN VALLEY ARE EXPECTED TO
WEAKEN...HOWEVER HRRR DOES HOLD ONTO AT LEAST SOME RAIN SHOWERS BY
EARLY MORNING. THEREFORE DID KEEP THE VCSH CLOSE TO 12Z AND SEEMS
REASONABLE WHEN TIMING THE CURRENT PROGRESSION OF THE AREA OF
SHOWERS. WHILE THE RIDGE DOES BEGIN TO BREAKDOWN TOMORROW THINK
FORECAST WILL STAY PRETTY CLOSE TO THE SAME WITH
DIURNALLY/AFTERNOON DRIVEN THUNDERSTORMS. DID OPT TO KEEP THE VCTS
IN THERE FOR EARLY AFTERNOON...BUT DID ADJUST TIMING UP SLIGHTLY.
WINDS ARE EXPECTED TO BE LIGHT TONIGHT...BUT DID BRING WINDS UP
TOMORROW AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DJ
LONG TERM...HAL
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
350 AM EDT MON MAY 18 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON MAY 18 2015
03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER
MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE
CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL
THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT
UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS
CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE
THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY
MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN
KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS
ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED
ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST
FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY.
THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND
17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT
LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN
PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE
ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA
SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE
MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE
THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED
CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE
THIS AFTERNOON.
ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES
OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND
CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID
KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK
THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER
AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY
SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 350 AM EDT MON MAY 18 2015
LONG TERM DISCUSSION WILL BE ISSUES SHORTLY...
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 135 AM EDT MON MAY 18 2015
TAFS TONIGHT WILL START OFF VFR WITH SOME MVFR POSSIBLE OVERNIGHT
AND EARLY TUESDAY MORNING. THE MVFR WILL BE WITH FOG POTENTIAL AND
DID STAY CLOSE TO PREVIOUS TAF AT THIS TIME. THE UNCERTAINTY WITH
THIS REMAINS TO SEE HOW CLOUDS COULD WANE THE DEVELOPMENT. THE
FOG WILL HAVE THE BEST POTENTIAL IN THE RIVER VALLEYS AND
LOCATIONS THAT RECEIVED RAIN TODAY. SOME SHOWERS AND
THUNDERSTORMS SOUTH ACROSS THE TN VALLEY ARE EXPECTED TO
WEAKEN...HOWEVER HRRR DOES HOLD ONTO AT LEAST SOME RAIN SHOWERS BY
EARLY MORNING. THEREFORE DID KEEP THE VCSH CLOSE TO 12Z AND SEEMS
REASONABLE WHEN TIMING THE CURRENT PROGRESSION OF THE AREA OF
SHOWERS. WHILE THE RIDGE DOES BEGIN TO BREAKDOWN TOMORROW THINK
FORECAST WILL STAY PRETTY CLOSE TO THE SAME WITH
DIURNALLY/AFTERNOON DRIVEN THUNDERSTORMS. DID OPT TO KEEP THE VCTS
IN THERE FOR EARLY AFTERNOON...BUT DID ADJUST TIMING UP SLIGHTLY.
WINDS ARE EXPECTED TO BE LIGHT TONIGHT...BUT DID BRING WINDS UP
TOMORROW AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DJ
LONG TERM...HAL
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
145 AM EDT MON MAY 18 2015
.UPDATE...
ISSUED AT 145 AM EDT MON MAY 18 2015
AREA OF SHOWERS MOVING SLOWLY EAST ALONG THE TN/KY BORDER
CONTINUE TO DIMINISH AT THIS LATE NIGHT HOUR. THIS WEAKENING TREND
IS EXPECTED TO CONTINUE AND DID UPDATE POP GRIDS TO REFLECT THIS
THOUGHT. THERE IS STILL SOME QUESTION AS TO HOW MUCH FOG WE WILL
SEE WITH SOME AREAS ABLE TO CLEAR OUT...WHILE OTHERS MAY SEE
LITTLE CLEARING. RIGHT NOW THINK THE BEST CHANCES WILL BE ALONG
RIVER VALLEYS AND AREAS THAT RECEIVED RAIN EARLY TODAY AND
TONIGHT. UPDATED GRIDS WITH LATEST OBS AND TRENDS WITH NO MAJOR
CHANGES NEEDED AT THIS POINT.
UPDATE ISSUED AT 1030 PM EDT SUN MAY 17 2015
THE EARLIER CLUSTER OF STORMS FELL APART AS THEY ENCOUNTERED CELLS
RUNNING OUT AHEAD OF THEIR LINE AND IN THE FACE OF A WEAKENING
COLD POOL. ACCORDINGLY...HAVE UPDATED THE FORECAST TO LOWER POPS
THROUGH THE REST OF THE NIGHT AND FINE TUNE SKY COVER. ALSO
ADJUSTED THE T AND TD GRIDS TO REFLECT THE LATEST SHORTBLEND
GUIDANCE...OBS...AND TRENDS. THESE UPDATED GRIDS HAVE BEEN SENT
TO THE NDFD AND WEB SERVERS. FRESHENED ZONES HAVE ALSO BEEN
ISSUED.
UPDATE ISSUED AT 730 PM EDT SUN MAY 17 2015
23Z SFC ANALYSIS SHOWS A FAIRLY TIGHT GRADIENT OVER THE AREA
BETWEEN HIGH PRESSURE TO THE SOUTHEAST AND BROAD LOW PRESSURE TO
THE NORTHWEST. THE DIURNAL CYCLE BROUGHT ANOTHER ROUND OF SHOWERS
AND THUNDERSTORMS TO EAST KENTUCKY THAT HAVE NOW WANED. HOWEVER...
AN ARC OF MORE ORGANIZED STORMS IS NOW MOVING EAST THROUGH CENTRAL
KENTUCKY. THIS AREA HAS DEVELOPED A COLD POOL AND THIS SHOULD
HELP IT HOLD TOGETHER AS IT APPROACHES THE SOUTHWEST PARTS OF THE
CWA OVER THE NEXT COUPLE OF HOURS. A FEW STORMS HAVE POPPED UP
AHEAD OF THESE AND MAY HELP TO BREAK UP THE LINE OR LOCALLY
ENHANCE IT. THE NEAR TERM MODELS HAVE NOT CAPTURED THIS MESOSCALE
FEATURE WELL AND FOR THE MOST PART DAMPEN IT OUT FAR TOO QUICK.
FOR OUR FORECAST...HAVE BEEFED UP POPS ALONG THIS LINE OF
STORMS...AND THE COLD POOL SHOWERS BEHIND IT...AS IT TRACKS
THROUGH THE CWA BETWEEN NOW AND 04Z. THIS ENTAILED HIGHER QPF AS
WELL AS GUSTIER WINDS AMID THE PASSAGE. LATER AS THE CLOUDS START
TO BREAK UP IN THE WAKE OF THE STORMS AND STRATIFORM RAIN...EXPECT
PATCHY FOG TO DEVELOP AND LINGER THROUGH DAWN...MAINLY IN THE
VALLEYS. THE WHOLE FORECAST HAS BEEN UPDATED FOR THE NIGHT ALSO
INCORPORATING THE LATEST SHORTBLEND GUIDANCE...OBS...AND TRENDS.
THESE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
ADDITIONALLY...A NEW SET OF ZONES IS FORTHCOMING.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EDT SUN MAY 17 2015
THE HRRR MODEL HAS HAD THE BEST HANDLE ON THIS AFTERNOONS SHOWER
AND STORM ACTIVITY...WITH THE BULK OF CURRENT ACTIVITY OCCURRING
IN OUR FAR WESTERN COUNTIES. THE NAM12 HAS BEEN KEEPING CONVECTIVE
ACTIVITY MOST EXTENSIVE ACROSS OUR FAR EASTERN COUNTIES...WHICH IS
THE OPPOSITE OF WHAT IS ACTUALLY HAPPENING. THEREFORE...THE HRRR
SOLUTION WAS USED TO COMPOSE THE FIRST 12 HOURS OF THE SHORT TERM
FORECAST...AFTER 12Z...THE CONSALL SOLUTION WAS USED FOR THE
FORECAST. MORE SHOWERS AND STORMS WILL CONTINUE TO FORM WEST AND
SOUTHWEST OF THE AREA THROUGH THIS EVENING...AND THIS ACTIVITY
WILL SLOWLY MOVE WESTWARD INTO AND ACROSS EASTERN KENTUCKY THROUGH
0Z OR SO. AFTER THAT...ONCE THE SUN IS DOWN AND LOSS OF HEATING
OCCURS...THE SHOWERS AND STORMS WILL DROP OFF IN COVERAGE PRETTY
QUICKLY. AFTER HIGH RAIN CHANCES THIS AFTERNOON AND EVENING...THE
OVERNIGHT HOURS ARE FORECAST TO SEE ONLY ISOLATED SHOWERS AND
STORMS. SHOWERS AND STORMS WILL BE ON THE INCREASE AGAIN ON
MONDAY...BEGINNING IN THE LATE MORNING HOURS...AS A COLD FRONT
SLOWLY APPROACHES FROM THE WEST. THE PEAK OF ACTIVITY LOOKS TO BE
DURING THE AFTERNOON AND EVENING HOURS ONCE AGAIN...DURING PEAK
HEATING AND FRONTAL PASSAGE. SOME OF THE STRONGER STORMS COULD
PRODUCE LOCALLY HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING.
TEMPERATURES DURING THE SHORT TERM ARE STILL ON TRACK TO RUN WELL
ABOVE NORMAL FOR THIS TIME OF YEAR...REMAINING IN STEP WITH
CURRENT TRENDS AND A PERSISTENT SOUTHERLY FLOW PATTERN THAT HAS
BEEN CONSISTENTLY PUMPING WARM MOIST AIR OFF THE GULF OF MEXICO
INTO THE REGION. HIGHS ON MONDAY ARE STILL EXPECTED TO TOP OUT IN
THE LOWER 80S ACROSS THE AREA...WITH OVERNIGHT LOWS TONIGHT AND
TOMORROW NIGHT ONLY FALLING INTO THE LOW TO MID 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 300 PM EDT SUN MAY 17 2015
MODELS APPEAR TO BE IN GOOD AGREEMENT WITH THE MID AND UPPER LEVEL
PATTERN OVER OUR REGION...BUT DIFFER MORE ON DETAILS OF SENSIBLE
WEATHER WITH A SHORTWAVE DISTURBANCE LATE WEDNESDAY OR WEDNESDAY
NIGHT INTO EARLY THURSDAY.
IN GENERAL ZONAL FLOW WILL DOMINATE THE PATTERN UNTIL THE LAST 48
HOURS OF THE EXTENDED WHERE SHORT WAVE RIDGING WILL BUILD INTO AND
ACROSS THE OHIO VALLEY IN RESPONSE TO EASTWARD MOVEMENT OF WEST
COAST CUT OFF LOW. AT THE SURFACE A COOL CANADIAN AIR MASS...HIGH
PRESSURE SYSTEM WILL SETTLE DOWN INTO THE HEART OF THE CONUS BEHIND
AN EXITING COLD FRONT...NOSING ITS WAY INTO THE OHIO VALLEY. AS A
RESULT WE CAN EXPECT DRY...PLEASANTLY COOL WEATHER FOR THE START OF
THE EXTENDED. ALOFT...THE AFOREMENTIONED DISTURBANCE WILL ROUND A
DEEP HUDSON BAY LOW WEDNESDAY NIGHT. WE APPEAR TO RECEIVE A GLANCING
BLOW FROM THIS FEATURE AS IT TRACKS THROUGH THE GREAT LAKES REGION.
A SECOND LESS IMPRESSIVE DISTURBANCE BRUSHES THE OHIO VALLEY BY LATE
IN THE WEEK...DY6 FRI.
THE MAIN FORECAST CHALLENGE IN THE EXTENDED WILL BE THE SHORT WAVE
DISTURBANCE MOVING THROUGH THE AREA WEDNESDAY NIGHT INTO EARLY
THURSDAY. THE 0Z AND 12Z ECMWF PRODUCE CONSIDERABLY MORE SENSIBLE
WEATHER WITH THIS FEATURE THAN EITHER THE 0Z OR 12Z GFS. NOT SEEING
MUCH IN THE WAY OF TRENDS TO HELP WITH PREFERENCE OF SOLUTIONS.
THEREFORE RELIED STRONGLY ON MODEL BLENDS CONSIDERING THE MURKY
DETAILS WITH SENSIBLE WEATHER. INCREASING HEIGHTS THROUGH THE END OF
THE EXTENDED WILL MEAN A GRADUAL RISE IN TEMPS...INTO THE 80S BY THE
END OF THE FORECAST WINDOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 135 AM EDT MON MAY 18 2015
TAFS TONIGHT WILL START OFF VFR WITH SOME MVFR POSSIBLE OVERNIGHT
AND EARLY TUESDAY MORNING. THE MVFR WILL BE WITH FOG POTENTIAL AND
DID STAY CLOSE TO PREVIOUS TAF AT THIS TIME. THE UNCERTAINTY WITH
THIS REMAINS TO SEE HOW CLOUDS COULD WANE THE DEVELOPMENT. THE
FOG WILL HAVE THE BEST POTENTIAL IN THE RIVER VALLEYS AND
LOCATIONS THAT RECEIVED RAIN TODAY. SOME SHOWERS AND
THUNDERSTORMS SOUTH ACROSS THE TN VALLEY ARE EXPECTED TO
WEAKEN...HOWEVER HRRR DOES HOLD ONTO AT LEAST SOME RAIN SHOWERS BY
EARLY MORNING. THEREFORE DID KEEP THE VCSH CLOSE TO 12Z AND SEEMS
REASONABLE WHEN TIMING THE CURRENT PROGRESSION OF THE AREA OF
SHOWERS. WHILE THE RIDGE DOES BEGIN TO BREAKDOWN TOMORROW THINK
FORECAST WILL STAY PRETTY CLOSE TO THE SAME WITH
DIURNALLY/AFTERNOON DRIVEN THUNDERSTORMS. DID OPT TO KEEP THE VCTS
IN THERE FOR EARLY AFTERNOON...BUT DID ADJUST TIMING UP SLIGHTLY.
WINDS ARE EXPECTED TO BE LIGHT TONIGHT...BUT DID BRING WINDS UP
TOMORROW AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...AR
LONG TERM...AR
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
135 AM EDT MON MAY 18 2015
.UPDATE...
ISSUED AT 1030 PM EDT SUN MAY 17 2015
THE EARLIER CLUSTER OF STORMS FELL APART AS THEY ENCOUNTERED CELLS
RUNNING OUT AHEAD OF THEIR LINE AND IN THE FACE OF A WEAKENING
COLD POOL. ACCORDINGLY...HAVE UPDATED THE FORECAST TO LOWER POPS
THROUGH THE REST OF THE NIGHT AND FINE TUNE SKY COVER. ALSO
ADJUSTED THE T AND TD GRIDS TO REFLECT THE LATEST SHORTBLEND
GUIDANCE...OBS...AND TRENDS. THESE UPDATED GRIDS HAVE BEEN SENT
TO THE NDFD AND WEB SERVERS. FRESHENED ZONES HAVE ALSO BEEN
ISSUED.
UPDATE ISSUED AT 730 PM EDT SUN MAY 17 2015
23Z SFC ANALYSIS SHOWS A FAIRLY TIGHT GRADIENT OVER THE AREA
BETWEEN HIGH PRESSURE TO THE SOUTHEAST AND BROAD LOW PRESSURE TO
THE NORTHWEST. THE DIURNAL CYCLE BROUGHT ANOTHER ROUND OF SHOWERS
AND THUNDERSTORMS TO EAST KENTUCKY THAT HAVE NOW WANED. HOWEVER...
AN ARC OF MORE ORGANIZED STORMS IS NOW MOVING EAST THROUGH CENTRAL
KENTUCKY. THIS AREA HAS DEVELOPED A COLD POOL AND THIS SHOULD
HELP IT HOLD TOGETHER AS IT APPROACHES THE SOUTHWEST PARTS OF THE
CWA OVER THE NEXT COUPLE OF HOURS. A FEW STORMS HAVE POPPED UP
AHEAD OF THESE AND MAY HELP TO BREAK UP THE LINE OR LOCALLY
ENHANCE IT. THE NEAR TERM MODELS HAVE NOT CAPTURED THIS MESOSCALE
FEATURE WELL AND FOR THE MOST PART DAMPEN IT OUT FAR TOO QUICK.
FOR OUR FORECAST...HAVE BEEFED UP POPS ALONG THIS LINE OF
STORMS...AND THE COLD POOL SHOWERS BEHIND IT...AS IT TRACKS
THROUGH THE CWA BETWEEN NOW AND 04Z. THIS ENTAILED HIGHER QPF AS
WELL AS GUSTIER WINDS AMID THE PASSAGE. LATER AS THE CLOUDS START
TO BREAK UP IN THE WAKE OF THE STORMS AND STRATIFORM RAIN...EXPECT
PATCHY FOG TO DEVELOP AND LINGER THROUGH DAWN...MAINLY IN THE
VALLEYS. THE WHOLE FORECAST HAS BEEN UPDATED FOR THE NIGHT ALSO
INCORPORATING THE LATEST SHORTBLEND GUIDANCE...OBS...AND TRENDS.
THESE GRIDS HAVE BEEN SENT TO THE NDFD AND WEB SERVERS.
ADDITIONALLY...A NEW SET OF ZONES IS FORTHCOMING.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 300 PM EDT SUN MAY 17 2015
THE HRRR MODEL HAS HAD THE BEST HANDLE ON THIS AFTERNOONS SHOWER
AND STORM ACTIVITY...WITH THE BULK OF CURRENT ACTIVITY OCCURRING
IN OUR FAR WESTERN COUNTIES. THE NAM12 HAS BEEN KEEPING CONVECTIVE
ACTIVITY MOST EXTENSIVE ACROSS OUR FAR EASTERN COUNTIES...WHICH IS
THE OPPOSITE OF WHAT IS ACTUALLY HAPPENING. THEREFORE...THE HRRR
SOLUTION WAS USED TO COMPOSE THE FIRST 12 HOURS OF THE SHORT TERM
FORECAST...AFTER 12Z...THE CONSALL SOLUTION WAS USED FOR THE
FORECAST. MORE SHOWERS AND STORMS WILL CONTINUE TO FORM WEST AND
SOUTHWEST OF THE AREA THROUGH THIS EVENING...AND THIS ACTIVITY
WILL SLOWLY MOVE WESTWARD INTO AND ACROSS EASTERN KENTUCKY THROUGH
0Z OR SO. AFTER THAT...ONCE THE SUN IS DOWN AND LOSS OF HEATING
OCCURS...THE SHOWERS AND STORMS WILL DROP OFF IN COVERAGE PRETTY
QUICKLY. AFTER HIGH RAIN CHANCES THIS AFTERNOON AND EVENING...THE
OVERNIGHT HOURS ARE FORECAST TO SEE ONLY ISOLATED SHOWERS AND
STORMS. SHOWERS AND STORMS WILL BE ON THE INCREASE AGAIN ON
MONDAY...BEGINNING IN THE LATE MORNING HOURS...AS A COLD FRONT
SLOWLY APPROACHES FROM THE WEST. THE PEAK OF ACTIVITY LOOKS TO BE
DURING THE AFTERNOON AND EVENING HOURS ONCE AGAIN...DURING PEAK
HEATING AND FRONTAL PASSAGE. SOME OF THE STRONGER STORMS COULD
PRODUCE LOCALLY HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING.
TEMPERATURES DURING THE SHORT TERM ARE STILL ON TRACK TO RUN WELL
ABOVE NORMAL FOR THIS TIME OF YEAR...REMAINING IN STEP WITH
CURRENT TRENDS AND A PERSISTENT SOUTHERLY FLOW PATTERN THAT HAS
BEEN CONSISTENTLY PUMPING WARM MOIST AIR OFF THE GULF OF MEXICO
INTO THE REGION. HIGHS ON MONDAY ARE STILL EXPECTED TO TOP OUT IN
THE LOWER 80S ACROSS THE AREA...WITH OVERNIGHT LOWS TONIGHT AND
TOMORROW NIGHT ONLY FALLING INTO THE LOW TO MID 60S.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 300 PM EDT SUN MAY 17 2015
MODELS APPEAR TO BE IN GOOD AGREEMENT WITH THE MID AND UPPER LEVEL
PATTERN OVER OUR REGION...BUT DIFFER MORE ON DETAILS OF SENSIBLE
WEATHER WITH A SHORTWAVE DISTURBANCE LATE WEDNESDAY OR WEDNESDAY
NIGHT INTO EARLY THURSDAY.
IN GENERAL ZONAL FLOW WILL DOMINATE THE PATTERN UNTIL THE LAST 48
HOURS OF THE EXTENDED WHERE SHORT WAVE RIDGING WILL BUILD INTO AND
ACROSS THE OHIO VALLEY IN RESPONSE TO EASTWARD MOVEMENT OF WEST
COAST CUT OFF LOW. AT THE SURFACE A COOL CANADIAN AIR MASS...HIGH
PRESSURE SYSTEM WILL SETTLE DOWN INTO THE HEART OF THE CONUS BEHIND
AN EXITING COLD FRONT...NOSING ITS WAY INTO THE OHIO VALLEY. AS A
RESULT WE CAN EXPECT DRY...PLEASANTLY COOL WEATHER FOR THE START OF
THE EXTENDED. ALOFT...THE AFOREMENTIONED DISTURBANCE WILL ROUND A
DEEP HUDSON BAY LOW WEDNESDAY NIGHT. WE APPEAR TO RECEIVE A GLANCING
BLOW FROM THIS FEATURE AS IT TRACKS THROUGH THE GREAT LAKES REGION.
A SECOND LESS IMPRESSIVE DISTURBANCE BRUSHES THE OHIO VALLEY BY LATE
IN THE WEEK...DY6 FRI.
THE MAIN FORECAST CHALLENGE IN THE EXTENDED WILL BE THE SHORT WAVE
DISTURBANCE MOVING THROUGH THE AREA WEDNESDAY NIGHT INTO EARLY
THURSDAY. THE 0Z AND 12Z ECMWF PRODUCE CONSIDERABLY MORE SENSIBLE
WEATHER WITH THIS FEATURE THAN EITHER THE 0Z OR 12Z GFS. NOT SEEING
MUCH IN THE WAY OF TRENDS TO HELP WITH PREFERENCE OF SOLUTIONS.
THEREFORE RELIED STRONGLY ON MODEL BLENDS CONSIDERING THE MURKY
DETAILS WITH SENSIBLE WEATHER. INCREASING HEIGHTS THROUGH THE END OF
THE EXTENDED WILL MEAN A GRADUAL RISE IN TEMPS...INTO THE 80S BY THE
END OF THE FORECAST WINDOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 135 AM EDT MON MAY 18 2015
TAFS TONIGHT WILL START OFF VFR WITH SOME MVFR POSSIBLE OVERNIGHT
AND EARLY TUESDAY MORNING. THE MVFR WILL BE WITH FOG POTENTIAL AND
DID STAY CLOSE TO PREVIOUS TAF AT THIS TIME. THE UNCERTAINTY WITH
THIS REMAINS TO SEE HOW CLOUDS COULD WANE THE DEVELOPMENT. THE
FOG WILL HAVE THE BEST POTENTIAL IN THE RIVER VALLEYS AND
LOCATIONS THAT RECEIVED RAIN TODAY. SOME SHOWERS AND
THUNDERSTORMS SOUTH ACROSS THE TN VALLEY ARE EXPECTED TO
WEAKEN...HOWEVER HRRR DOES HOLD ONTO AT LEAST SOME RAIN SHOWERS BY
EARLY MORNING. THEREFORE DID KEEP THE VCSH CLOSE TO 12Z AND SEEMS
REASONABLE WHEN TIMING THE CURRENT PROGRESSION OF THE AREA OF
SHOWERS. WHILE THE RIDGE DOES BEGIN TO BREAKDOWN TOMORROW THINK
FORECAST WILL STAY PRETTY CLOSE TO THE SAME WITH
DIURNALLY/AFTERNOON DRIVEN THUNDERSTORMS. DID OPT TO KEEP THE VCTS
IN THERE FOR EARLY AFTERNOON...BUT DID ADJUST TIMING UP SLIGHTLY.
WINDS ARE EXPECTED TO BE LIGHT TONIGHT...BUT DID BRING WINDS UP
TOMORROW AFTERNOON.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...AR
LONG TERM...AR
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
459 AM CDT MON MAY 18 2015
.SYNOPSIS...
LATEST UA ANALYSIS AND WV IMAGERY SHOWS A MOIST SWLY FLOW ALOFT
CONTINUING WITH A BROAD TROF OVER THE WRN CONUS AND A RIDGE OVER THE
SE. A PAIR OF LOWS WERE SPINNING WITHIN THE TROF...ONE CROSSING THE
NRN PLAINS AND ANOTHER ENTERING CA. MEANWHILE...A PERTURBATION
OVERRIDING AN OUTFLOW BOUNDARY LEFT BEHIND FROM LAST NIGHTS MCV
WAS PRODUCING AN INCREASE IN SHOWERS AND THUNDERSTORMS ACRS NRN LA
WITH SCT ACTIVITY DEVELOPING DOWN TO OUR NRN TIER OF PARISHES AND
COUNTIES. AT THE SFC...S-SE WINDS AROUND THE WRN PERIPHERY OF HIGH
PRES OFF THE SE ATL COAST CONTINUE TO STREAM GULF MOISTURE OVER
THE REGION.
&&
.DISCUSSION...
MAIN FCST CONCERN IN THE NEAR TERM IS RAIN CHCS AND THE POTENTIAL
FOR HEAVY RAINFALL. CONVECTION ACRS NRN LA INTO E TX WILL CONTINUE
TO INCREASE THROUGH THE MORNING AS SLY/SWLY WINDS SPREAD ABUNDANT
MOISTURE OVER THE REGION. LIFT WILL BE AUGMENTED BY DIFFLUENCE
ALOFT AND LOW LVL FORCING ALONG THE REMNANT BOUNDARY ACRS CNTL LA
AND THIS WILL HELP TO FOCUS THE PRECIPITATION ACRS NRN/CNTL LA.
RECENT HRRR AND NAM PROGS INDICATE CONVECTION SHOULD SLOWLY
PROPAGATE SOUTHWARD DURING THE DAY. AT THIS TIME...THE HIGHEST
RAINFALL TOTALS ARE EXPECTED TO REMAIN NORTH OF THE CWA.
HOWEVER...PRECIP WATER VALUES ARE RUNNING BETWEEN 1.8-2.0 INCHES
OVER THE AREA...MORE THAN ADEQUATE TO PRODUCE EFFICIENT RAINFALL
RATES AND LOCALIZED HEAVY RAIN ESPECIALLY ACRS THE NRN TIER OF
ZONES. HAVE HELD OFF ON ISSUANCE OF A FLASH FLOOD WATCH FOR NOW
WITH FLOODING EXPECTED TO BE MOSTLY LOCALIZED IN NATURE...BUT WILL
NEED TO MONITOR TRENDS FOR POSSIBLY ISSUANCE LATER THIS MORNING.
RAIN CHCS WILL DIMINISH DURING THE EVENING WITH THE LOSS OF
DAYTIME HEATING. A WEAK FRONT WILL SAG SOUTH INTO THE AREA
TUESDAY...BECOMING STALLED NW-SE ACRS NERN TX INTO CNTL LA. THE
PERSISTENT MOIST SWLY FLOW ALOFT AND EMBEDDED DISTURBANCES WILL
AGAIN BRING ABOUT SCT CONVECTION ON TUESDAY. ALTHOUGH COVERAGE IS
EXPECTED TO BE SLIGHTLY LESS THAN TODAY...EXPECT THE HIGHEST POPS
WILL BE CONCENTRATED ALONG THE FRONTAL BOUNDARY ACRS CNTL LA.
WEAK FLAT RIDGING WILL BEGIN TO DEVELOP ALOFT BY
MIDWEEK...HELPING TO REDUCE BUT NOT ELIMINATE SHOWER COVERAGE AND
CHANCES ON WEDNESDAY. ANOTHER FRONT IS FCST TO MOVE INTO THE AREA
THURSDAY...BRINGING ANOTHER ROUND OF SCT SHOWERS AND TSTMS. THE
FRONT WILL STALL NEAR THE COAST FRIDAY THEN SLOWLY RETREAT BACK
NORTH OVER THE WEEKEND. THE RIDGE ALOFT WILL KEEP RAIN CHCS CLOSER
TO 20-30 PERCENT FOR FRIDAY AND SATURDAY...WITH POPS EASING BACK
INTO THE SCT RANGE BY SUNDAY AS THE RIDGE GETS SHIFTED BACK TO THE
EAST OVER THE WEEKEND.
THROUGH THE NEXT FEW DAYS...THE THREAT FOR ANY ORGANIZED SVR
STORMS WILL REMAIN WELL WEST OF THE AREA. HOWEVER...A FEW ISLTD
STORMS COULD PULSE TO STRONG OR MARGINALLY SVR LIMITS DURING THE
AFTN WHEN MAX HEATING CONTRIBUTES TO ENHANCED INSTABILITY. THE
PRIMARY THREAT WILL STILL BE HEAVY RAINFALL AND LOCALIZED FLOODING
IN LOW-LYING OR URBAN AREAS.
LITTLE VARIATION IN TEMPERATURE IS EXPECTED THROUGH NEXT WEEKEND
WITH MAIN IMPACTS TO DAILY TEMPS FROM CLOUDS AND SHOWERS. IN
GENERAL...EXPECT LOWS FROM AROUND 70 INTO THE MIDDLE 70S WHICH IS
ABOUT 5-10 DEGREES ABV NORMAL WHILE HIGHS WILL RUN NEAR NORMAL IN
THE MIDDLE 80S.
&&
.MARINE...
MODT SELY WINDS WERE OCCURRING OVER THE COASTAL WATERS THIS EARLY
MORNING IN RESPONSE TO ELEVATED WINDS ALOFT AND INFLOW INTO
COMPLEX OF STORMS ACRS NRN LA INTO SE TX. SUSTAINED WINDS HAVE
APPROACHED 20 KNOTS AT TIMES. WITH THIS IN MIND...ADDED EXERCISE
CAUTION HEADLINE TO CWF FOR EARLY THIS MORNING. WINDS WILL
DIMINISH DURING THE MORNING.
OTHERWISE...EXPECT A LT TO MODT ONSHORE FLOW CONTINUING THROUGH
THE WEEK AS HIGH PRES REMAINS EAST OF THE REGION. WIDELY SCT
SHOWERS AND TSTMS WILL BE POSSIBLE THROUGH WEDNESDAY AS A SERIES
OF DISTURBANCES CROSSES THE REGION. CONVECTION WILL BECOME MORE
ISLTD TOWARD THE END OF THE WEEK AS WEAK RIDGING BUILDS IN ALOFT.
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 84 68 86 70 / 70 30 40 30
LCH 86 72 86 73 / 50 20 30 20
LFT 87 72 86 72 / 50 20 50 20
BPT 87 75 86 74 / 50 20 20 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT EXERCISE CAUTION UNTIL 9 AM CDT THIS MORNING FOR
GMZ430-432-435-450-452-455-470-472-475.
&&
$$
PUBLIC...24
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1154 PM CDT SUN MAY 17 2015
.AVIATION...
REDEVELOPMENT OF TSTMS IS EXPECTED OVER THE NEXT FEW HOURS...WITH
N LA TERMINALS MOST PRONE TO BE AFFECTED. CONVECTION IS EXPECTED
AT LEAST INTERMITTENTLY FOR THE ENTIRE 06Z TAF PD. FOR
TONIGHT...LIGHT WINDS AND MOIST SOILS FROM PREVIOUS RAINS WILL
ALLOW FOR SOME PATCHY FOG DEVELOPMENT...ESPECIALLY WHERE CLOUDS
ARE ABLE TO THIN OUT. ADDITIONALLY...PATCHY MVFR STRATUS WILL BE
POSSIBLE AT A FEW OF THE TERMINALS AS WELL. OTHERWISE...EXPECT SLY
WINDS GENERALLY LESS THAN 10 KTS THROUGHOUT THE PD. /12/
&&
.PREV DISCUSSION... /ISSUED 1032 PM CDT SUN MAY 17 2015/
UPDATE...
TO MAKE ADJUSTMENTS TO THE RAIN CHANCES TONIGHT THROUGH MONDAY
NIGHT AND CONTINUED THE THREAT FOR FLASH FLOODING FOR EAST AND
NORTHEAST TEXAS...NORTHWEST AND NORTH CENTRAL LOUISIANA AND
ADJACENT SOUTHWEST AND SOUTH CENTRAL ARKANSAS AND SOUTHEAST
OKLAHOMA.
DISCUSSION...
A CONTINUED SOUTHERLY FLOW OF GULF MOISTURE TO GO ALONG WITH A
CONTRIBUTING SUPPLY OF PACIFIC MOISTURE AND A SERIES OF UPPER
LEVEL DISTURBANCES RIDING TOWARD THE FOUR STATE REGION WILL
CONTINUE TO PROVIDE SHOWERS AND THUNDERSTORMS OVERNIGHT. SOME OF
THE STORMS WILL DEVELOP AND SPREAD OVER THE SAME AREAS THAT HAVE
HAD LOCALLY HEAVY RAIN LATELY RESULTING IN FLASH FLOODING. /06/
PREV DISCUSSION... /ISSUED 455 PM CDT SUN MAY 17 2015/
DISCUSSION...
MOST OF THE REMNANTS OF THE MORNING MCS HAVE EXITED THE REGION AS
OF 2115Z...ALTHOUGH SCT CONVECTION HAS REDEVELOPED OVER SE TX/SW
LA AND HAVE BEGUN TO SPREAD NE INTO THE HIGHER INSTABILITY AIR
WHERE MLCAPES STILL RANGE FROM 2000-2500 J/KG. BELIEVE THAT MUCH
OF THIS CONVECTION WILL GRADUALLY DIMINISH BY EARLY/MID EVENING
WITH THE LOSS OF HEATING/STABILITY. HOWEVER...OUR FOCUS WILL TURN
TO THE W AS THE AFTERNOON WATER VAPOR IMAGERY DEPICTS A WELL-
DEFINED SHORTWAVE OVER ERN NM ENTERING FAR W TX...WHICH REMAINS
PROGGED TO LIFT NE ACROSS THE RED RIVER VALLEY LATE THIS
EVENING/OVERNIGHT. THE AIR MASS OVER E TX/SE OK/SW AR REMAINS
SOMEWHAT STABLE THIS AFTERNOON IN WAKE OF THE MORNING
MCS...ALTHOUGH SBCIN HAS WEAKENED OVER THIS AREA OVER THE LAST FEW
HOURS AS SOME HEATING HAS OCCURRED BENEATH THE DENSE CONVECTIVE
DEBRIS IN PLACE. THE SHORT TERM PROGS ARE IN GENERAL AGREEMENT
WITH SCT CONVECTION REDEVELOPING LATER THIS EVENING OVER THE
REGION...ATOP A STILL MOIST AND SOMEWHAT UNSTABLE AIRMASS WHERE
DIFLUENT FLOW ALOFT SPREADS OVER THE REGION. COULD ALREADY BE
SEEING EVIDENCE OF THE FORCING ALOFT OVER SCNTRL/WCNTRL TX...WHERE
VISIBLE SATELLITE IMAGERY DEPICTS AN ELEVATED CU/AC FIELD
DEVELOPING OVER THESE AREAS. THE NAM/GFS ARE A LITTLE MORE
AGGRESSIVE IN DEVELOPING SCT CONVECTION BY MID TO LATE
EVENING...WITH THE HRRR A BIT SLOWER /AFTER 06Z/ OVER NE TX/SW
AR/POSSIBLY NW LA. HOWEVER...QPF PLACEMENTS VARY CONSIDERABLE WITH
THE MODELS THIS AFTERNOON...AND HAVE TAKEN A BLEND OF THE MODELS
AND ISSUED A FLASH FLOOD WATCH FROM 03Z THIS EVENING THROUGH 18Z
MONDAY FOR MUCH OF E TX/SE OK/SW AR/NW LA. THESE AREAS REMAIN
SATURATED FROM HEAVY RAINFALL THAT HAS FALLEN OVER THE LAST COUPLE
OF WEEKS...AND WILL BE FAIR GAME FOR CELL TRAINING LATER TONIGHT.
HAVE ADDED HEAVY RAINFALL TO THE FORECAST LATE TONIGHT THROUGH
MONDAY MORNING FOR THE WATCH AREA...AS PW/S CLIMB TO 1.8-2.0
INCHES...VERY NEAR THE MAX MOVING AVERAGE OF CLIMO FOR THE DATE.
AREAS TO THE SE OVER THE SRN SECTIONS OF NCNTRL LA HAVE NOT SEEN
NEARLY AS MUCH RAIN AS AREAS FARTHER N AND W...AND SHOULD BE ABLE
TO TAKE THE HEAVY RAIN AS IT MOVES THROUGH THE AREAS MONDAY. THE
HEAVY RAINFALL/FLASH FLOOD THREAT OVER THE WATCH AREAS SHOULD
DIMINISH BY EARLY MONDAY AFTERNOON AS THE SHORTWAVE QUICKLY
SPREADS ENE INTO THE MID-SOUTH/LOWER MS VALLEY.
THE CLOSED LOW A CPL HUNDRED MILES W OF THE CA COAST THIS
AFTERNOON IS EXPECTED TO COME ASHORE INTO CA EARLY MONDAY...WITH
THE MAIN ATTENDANT TROUGH LIFTING NE INTO THE SRN ROCKIES BY
EARLY TUESDAY AND INTO THE PLAINS TUESDAY AFTERNOON. THIS TROUGH
WILL HELP TO AMPLIFY SOMEWHAT FLAT UPPER RIDGING ALOFT OVER THE
SRN PLAINS/MID AND LOWER MS VALLEY AND SE STATES TUESDAY...WITH
THE FLAT RIDGING PERSISTING THROUGH MUCH OF THIS WEEK. THE SHORT
TERM PROGS REMAIN IN AGREEMENT WITH A WEAK SFC FRONT BACKDOORING
SW INTO ERN OK/CNTRL AR TUESDAY MORNING BEFORE BECOMING
STATIONARY. PREFER THE NAM/ECMWF POSITION OF THE FRONT THAN THE
GFS...WHICH SEEMS MUCH TOO FAR S GIVEN THE LACK OF HEIGHT FALLS
ALOFT TO HELP DRIVE THE FRONT FARTHER S. THE FRONT SHOULD HELP
FOCUS SCT CONVECTION DURING PEAK HEATING TUESDAY...WHILE OTHER
ISOLATED TO WIDELY SCT CONVECTION DEVELOPS FARTHER S WHERE
INSTABILITY/MOISTURE LIE OVER E TX/N LA...EVEN A WEAK
PERTURBATIONS SHIFT E ATOP THE FLAT RIDGE ALOFT. THE SFC FRONT
SHOULD LIFT BACK N TUESDAY NIGHT...BEFORE ANOTHER WEAK COOL FRONT
BEGINS TO BUILD S ACROSS OK/NW AR WEDNESDAY AFTERNOON. THE PROGS
ARE AGAIN KEYING IN WEAKNESSES IN THE FLOW ALOFT ATOP THE RIDGE TO
ENHANCE SCT CONVECTION DEVELOPMENT MAINLY OVER CNTRL/SRN OK/SW AR
WEDNESDAY AFTERNOON...BEFORE THE FRONT SLOWLY SLIDE INTO THE
REGION WEDNESDAY NIGHT/THURSDAY BEFORE BECOMING STATIONARY.
HAVE MAINTAINED LIKELY/HIGH CHANCE POPS WEDNESDAY NIGHT AHEAD OF
THE FRONT...WITH MID CHANCE POPS THURSDAY WITH THE FROPA. HAVING
THE SFC BNDRY AROUND THROUGH LATE FRIDAY WILL FOCUS SCT CONVECTION
DEVELOPMENT THROUGH LATE WEEK...BEFORE THE FRONT BEGINS TO LIFT
BACK N OUT OF THE AREA. TEMPS WILL REMAIN NEAR/SLIGHTLY ABOVE
CLIMO THROUGH MUCH OF THE PERIOD.
PRELIMS TO FOLLOW BELOW...
15
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 82 71 82 70 / 60 70 70 30
MLU 89 72 81 69 / 50 60 70 40
DEQ 79 68 83 67 / 80 50 40 40
TXK 80 70 83 68 / 80 60 50 40
ELD 84 70 81 68 / 60 70 70 40
TYR 78 71 82 69 / 80 60 50 30
GGG 78 70 82 69 / 80 70 60 30
LFK 81 72 82 71 / 80 40 70 30
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR ARZ050-051-
059>061-070>073.
LA...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR LAZ001>006-
010>012.
OK...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR OKZ077.
TX...FLASH FLOOD WATCH THROUGH MONDAY AFTERNOON FOR TXZ096-097-
108>112-124>126-136>138-149>153.
&&
$$
12
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
509 AM EDT MON MAY 18 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 508 AM EDT MON MAY 18 2015
WATER VAPOR LOOP AND RAP ANALYSIS SHOWS MID-LVL LOW ROTATING OVER
NRN MN WITH A DRY SLOT AHEAD OF LOW REACHING ACROSS MUCH OF THE
UPPER MI. COLD FRONT MOVING ACROSS MUCH OF THE AREA OVERNIGHT HAS
ALLOWED DRIER AIR TO ADVECT IN FROM THE SW WHICH HAS DISSIPATED THE
DENSE FOG OVER LAKE MI AND AREAS DOWNSTREAM OVER ERN UPPER MI. DRY
SLOT HAS LEFT UPPER MI GENERALLY PCPN FREE OVER THE EARLY MORNING
HRS.
TODAY AND TONIGHT...THE FOCUS TODAY WILL ON COLD SURGE WHICH WILL BE
MOVING INTO THE WEST MID-LATE MORNING AND CONTINUE EASTWARD THROUGH
THE DAY. AHEAD OF THE FRONT OVER THE EAST HALF OF UPPER MI AND AWAY
FROM THE MODERATING INFLUENCE OF LAKE MICHIGAN...SHOULD SEE
TEMPERATURES REACH IN THE MID TO UPPER 60S (WITH A FEW 70S POSSIBLE
IF THERE ARE BREAKS IN THE LOW CLOUDS). OVER THE WEST HALF WHERE
FRONTAL PASSAGE WILL OCCUR EARLIER...MORNING TO EARLY AFTERNOON HIGH
TEMPS WILL RANGE FROM UPPER 40S/50F NEAR IRONWOOD TO LOWER 60S ALONG
A LINE FM MQT TO MENOMINEE. IN ADDITION...ALL OF THE HIGHER
RESOLUTION MODELS ARE SURGING IN A LAKE BREEZE OFF LAKE SUPERIOR
(FROM MARQUETTE EASTWARD) WHICH WILL LEAD TO COOLER NORTHERLY FLOW
BY MID-LATE AFTERNOON OVER NCNTRL AREAS. WITH THE COLD AIR AND
ABUNDANT MOISTURE SURGING INTO THE AREA AS WINDS TURN
WESTERLY...EXPECT ISOLATED TO SCATTERED SHOWERS TO DEVELOP OVER THE
WEST FIRST (ESPECIALLY IN THE FAVORED UPSLOPE AREAS) AND THEN SPREAD
INTO THE CENTRAL AREAS EVENING AND POSSIBLY EASTERN COUNTIES LATE
EVENING/OVERNIGHT. CAA ON BLUSTERY NW TO N WINDS WILL ALLOW 8H TEMPS
TO FALL TO -8 TO -10C OVER MUCH OF THE WEST HALF OF UPPER MI BY 12Z
TUE. 8H TEMPS WILL FALL TO AROUND -5C OVER THE EAST HALF OVERNIGHT.
BEST FORCING OUT AHEAD ANOTHER SHORTWAVE TRACKING ALONG THE
MN/ONTARIO BORDER TONIGHT WILL STAY MAINLY NW OF UPPER MI KEEPING
MUCH OF THE ASSOCIATED LIGHT PCPN N OF UPPER MI. HOWEVER...DEEP
CYCLONIC FLOW/MOISTURE WILL STILL SUPPORT SOME LIGHT PCPN IN UPPER
MI AS WELL...ESPECIALLY IN THE UPSLOPE AREAS OF THE W AND N. WITH
COLD ADVECTION TAKING PLACE AS NOTED BEFORE...THE -SHRA WILL MIX
WITH OR CHANGE TO -SHSN TONIGHT FROM WEST TO EAST. DUE TO THE COLD
ADVECTION AND PCPN OCCURRING DURING THE OVERNIGHT HOURS...CAN`T RULE
OUT A DUSTING TO LOCALLY A HALFINCH OF SNOW ON GRASSY SFCS BY 12Z
TUE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON MAY 18 2015
TUESDAY WILL BRING ABOUT ONLY SLOWLY RISING TEMPS AS A SECONDARY
TROUGH/COLD FRONT SINKING ACROSS CENTRAL TO E UPPER MI. 850MB TEMPS
AT A CHILLY -10C OVER THE KEWEENAW PENINSULA /2-5C WARMER OFF THE
17/18Z AND 18/00Z GFS RUNS...AS WELL AS THE REGIONAL WRF/. THE NAM
IS THE COLDEST WITH THE ENTIRE W HALF AROUND -11C TUESDAY MORNING.
850MB TEMPS WILL FALL FROM AROUND -4C AT ERY TO AROUND -9C BY 18Z
TUESDAY ON NW WINDS. THIS WILL BE AS ANOTHER SHORTWAVE OVER NE MN AT
12Z SLIDES ACROSS LAKE SUPERIOR. YES...SNOW IS POSSIBLE STILL ON
TUESDAY...BUT MAY BE LIMITED TO JUST A DUSTING ON MAINLY GRASSY
SURFACES THROUGH THE MORNING HOURS...BEFORE THE LOW LEVEL RH
DIMINISHES SIGNIFICANTLY.
EXPECT BREEZY CONDITIONS...WITH GUSTS AVERAGING 20-25KTS ACROSS MUCH
OF THE CWA...STRONGEST ACROSS THE KEWEENAW PENINSULA AND E NEAR LAKE
SUPERIOR. DESPITE LIGHT W FLOW RETURNING AT THE SFC TUESDAY NIGHT
AND 850MB TEMPS WARMING TO AROUND 0C...LOWS NEAR TO SLIGHTLY BELOW
FREEZING WILL BE POSSIBLE /COLDEST IN THE TRADITIONAL COOL SPOTS OF
THE INTERIOR W HALF OF UPPER MI/.
EXPECT DRIER CONDITIONS WITH LIGHTER WINDS WEDNESDAY AS SFC TEMPS
REBOUND TO AROUND 60F. THIS WILL BE DESPITE THE 500MB TROUGH WITH
ITS NW FLOW LINGERING OVERHEAD...AS THE LARGE SFC HIGH OVER THE
DAKOTAS BUILDS A RIDGE ACROSS UPPER MI. PW VALUES SHOULD BE AROUND
0.25IN FROM OVERNIGHT TUESDAY NIGHT THROUGH MUCH OF WEDNESDAY
/ALTHOUGH SLIGHTLY HIGHER NEAR LAKE MI FROM LATE MORNING ON/.
DRY WEATHER SHOULD REMAIN THROUGH THE REST OF THE WORK WEEK AT NW
FLOW LINGERS AT 500MB. THERE WILL BE A WEAK COLD FRONT STRETCHING
ACROSS N LAKE SUPERIOR AT 00Z THURSDAY THAT SINKS ACROSS UPPER MI
WEDNESDAY EVENING AND LOWER MI DURING THE DAY THURSDAY. NOT
EXPECTING MUCH MORE THAN THE POSSIBILITY OF TEMPORARY ADDITIONAL
CLOUD COVER. HIGH PRESSURE WILL SLIDE IN BEHIND THE FRONTAL BOUNDARY
TO WRAP UP THE END OF THE WORK WEEK. EXPECT THIS HIGH TO SHIFT TO
THE LOWER GREAT LAKES BY 18Z SATURDAY AND OFF THE MID-ATLANTIC COAST
SUNDAY MORNING. THIS EXITING HIGH WILL ALLOW MOISTURE TO
RETURN...ALONG WITH A GOOD CHANCE OF SHOWERS FOR SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 137 AM EDT MON MAY 18 2015
RAIN IS PRETTY MUCH DONE UNTIL WRAPAROUND MOISTURE ARRIVES WITH SOME
SHOWERS LATER MON AFTERNOON AND EVENING AT IWD AND CMX. VFR
CONDITIONS WILL TRANSITION TO MVFR OVERNIGHT AT KIWD AND KCMX AS
WRAPAROUND MOISTURE ASSOC WITH THE LOW COMES IN. WRAPAROUND MOISTURE
WON`T REACH SAW UNTIL LATE MON AFTERNOON/EVENING SO EXPECT TRANSITION
FROM VFR TO MVFR CONDITIONS TO OCCUR THERE LATER IN THE DAY. SAW
WILL ALSO SEE A LAKE BREEZE MON AFTERNOON THAT WILL SWITCH THEIR WIND
TO THE NORTHEAST.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EDT MON MAY 18 2015
LOW PRES OVER NRN MN WILL MOVE ACROSS LAKE SUPERIOR TODAY INTO THIS
EVENING. AS A RESULT...WINDS ON LAKE SUPERIOR WILL VEER FM SW THIS
MORNING TO NNW LATE TODAY AND TONIGHT AND RAMP UP TO 20 TO 30 KTS
TONIGHT AND TUE...STRONGEST OVER THE EAST HALF. NOT OUT OF THE
QUESTION THAT THERE COULD BE SOME GALE FORCE GUSTS OVER THE E HALF
OF THE LAKE LATE TONIGHT/TUE MORNING. WINDS WILL DIMINISH W TO E TUE
AFTN/NIGHT AS A HIGH PRES RIDGE BUILDS IN FM THE WEST. WED THRU
FRI...WINDS WILL BE UNDER 20KT. LINGERING WARM MOIST AIR WILL ALLOW
FOG TO CONTINUE OVER THE LAKE TODAY...POSSIBLE LOCALLY DENSE OVER
THE EAST HALF THIS MORNING. ALL FOG SHOULD DISSIPATE BY THIS EVENING
AS COLDER AIR ARRIVES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...07
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
515 AM EDT MON MAY 18 2015
.SYNOPSIS...
A WARM AND HUMID AIR MASS WILL REMAIN OVER THE REGION WITH A PERIOD
OF SHOWERS AND THUNDERSTORMS PUSHING ACROSS WESTERN AND CENTRAL NEW
YORK TODAY AHEAD OF A COLD FRONT. SOME OF THESE THUNDERSTORMS MAY
BRING LOCALIZED HEAVY RAIN. THE FRONT WILL CROSS EARLY TUESDAY THEN
A COOLER AND DRIER AIRMASS WILL ARRIVE BEHIND THE FRONT FOR THE
REMAINDER OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE FORECAST AREA LIES BENEATH AN AMPLIFIED 500MB RIDGE THIS MORNING
WITH STACKED SURFACE AND UPPER LEVEL LOW OVER NORTHERN MINNESOTA
CONTINUING TO SPREAD WARM AND MOIST AIR NORTH ACROSS THE GREAT
LAKES. DEWPOINTS RUNNING CLOSE TO 60F ACROSS WESTERN NEW YORK WITH
MID 60S DEWPOINTS FOUND ACROSS MICHIGAN. SPC MESOSCALE ANALYSIS
SHOWS A RIBBON OF HIGH PRECIPITABLE WATER VALUES AROUND 1.7 INCHES
RUNNING FROM NORTH OF GEORGIAN BAY TO LAKE ERIE. PLENTY OF MOISTURE
TO BE FOUND SO FOCUS FOR TIMING OF SHOWER AND THUNDERSTORM ACTIVITY
TODAY WILL BE ON ANY SYNOPTIC/MESOSCALE FEATURES SHIFTING ACROSS
THE EASTERN GREAT LAKES.
A PRE-FRONTAL TROUGH IS ANALYZED ROUGHLY FROM NORTHERN MI SOUTHEAST
TO NEAR KERI. THIS IS FORECAST TO SHIFT ACROSS WESTERN AND CENTRAL
NEW YORK TODAY. LOOKING TO THE MID-LEVELS...FORCING MAY ALSO COME
FROM ANY SUBTLE SHORTWAVES ROLLING UP THE WEST SIDE OF THE RIDGE
AXIS FROM THE MISS VALLEY TOWARD THE EASTERN GREAT LAKES. MESOSCALE
GUIDANCE SUCH AS WRF AND HRRR MODELS SUGGEST A FEW ISOLATED SHOWERS
AND STORMS MAY WORK INTO WNY ALONG THE TROUGH THIS MORNING. BY EARLY
AFTERNOON FORECAST CAPE OF 2-3K J/KG WILL FEED MORE NUMEROUS SHOWERS
AND THUNDERSTORMS DEVELOPING FROM THE SOUTHERN TIER ACROSS THE
GENESEE VALLEY AND FINGER LAKES. A STABLE SOUTHWEST FLOW OFF LAKE
ERIE SHOULD KEEP MUCH OF THE NIAGARA FRONTIER PROTECTED FROM THE
HEAVIER STORMS BUT LAKE BREEZES COULD TRIGGER ADDITIONAL CELLS TO THE
SOUTH AND EAST OF BUFFALO. BULK SHEAR THIS AFTERNOON IS FORECAST
ONLY AROUND 15 KTS SO TOO WEAK TO SUPPORT ANY SIGNIFICANT WIND/HAIL
THREAT. THE DEEP MOISTURE IN PLACE PER PWATS AND SKINNY CAPE
PROFILES WITH SLOW STORM MOTIONS WILL HOWEVER BRING A RISK FOR
LOCALLY HEAVY RAIN AND FLOODING IF ANY TRAINING CELLS DEVELOPS.
TONIGHT...THE SURFACE LOW WILL SHIFT NORTH OF THE GREAT LAKES TO
SOUTHERN QUEBEC. NEAR-TERM MODELS INDICATE THE MAJORITY OF REMAINING
CONVECTION WILL BE LIMITED FROM THE FINGER LAKES EASTWARD ACROSS
CENTRAL AND EASTERN NEW YORK. WESTERN NEW YORK WILL LARGELY REMAIN
DRY. THE COLD FRONT WILL CROSS WNY LATE TONIGHT AND IS FORECAST TO
BE NEAR THE FINGER LAKES BY 12Z TUESDAY WITH SKY COVER THINNING FROM
WEST TO EAST. THE OVERNIGHT TIMING OF THE FRONT SHOULD LIMIT A
SECOND ROUND OF SHOWER/TSTM ACTIVITY.
TEMPERATURES TODAY WILL AGAIN RISE ABOVE NORMAL WITHIN A HUMID
AIRMASS. 850MB TEMPS OF NEAR +15C WILL SUPPORT SURFACE HIGH TEMPS
RANGING FROM THE UPPER 70S TO MID 80S. THE U70S TEMPS WILL ONLY BE
LIMITED BY EARLIER START TO CONVECTION WHILE MORE HEATING ACROSS
FINGER LAKES AND NORTH COUNTRY WILL HELP BOOST TEMPS TO THE M80S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
A STRONG COLD FRONT WILL CROSS THE FORECAST AREA DURING THE DAY ON
TUESDAY. WHILE THE BULK OF THE PRECIPITATION WILL BE ASSOCIATED WITH
THE PRE-FRONTAL TROUGH AND ALREADY WELL TO THE EAST OF THE FORECAST
AREA OVER THE ADIRONDACKS/GREEN MOUNTAINS BY TUESDAY MORNING...A FEW
SHOWERS WILL STILL BE POSSIBLE ALONG/JUST AHEAD OF THE COLD
FRONT...PARTICULARLY ACROSS THE NORTH COUNTRY WHERE THE APPROACH OF
THE COLD FRONT WILL COINCIDE WITH THE AFTERNOON DIURNAL HEATING
MAXIMUM.
OTHERWISE...LOOK FOR BREEZY CONDITIONS WITH FALLING TEMPERATURES
BEHIND THE COLD FRONT. A PERIOD OF POST-FRONTAL SUBSIDENCE AND
SUNSHINE WILL GIVE WAY TO INCREASING CLOUDS LATER IN THE DAY AND
INTO THE EVENING AS THE UPPER LEVEL TROUGH SWINGS THROUGH.
TEMPERATURES WILL CONTINUE TO FALL INTO THE 40S TUESDAY NIGHT...WITH
HIGHER ELEVATIONS DIPPING JUST BELOW THE 40 DEGREE MARK AS THE CORE
OF THE COLD AIR ALOFT MOVES ACROSS THE REGION. WITH 850MB TEMPS
FALLING BELOW -2C...WE MAY EVEN SEE A DECENT AMOUNT OF LAKE-ENHANCED
CLOUD COVER TUESDAY NIGHT AND INTO WEDNESDAY MORNING. THIS COLD AIR
ALOFT AND THE ASSOCIATED CLOUD COVER WILL AID IN MAKING WEDNESDAY
THE COLDEST DAY OF THIS WEEK WITH HIGHS ONLY TOPPING OUT IN THE LOW
TO MID 50S.
BY WEDNESDAY AFTERNOON WE SHOULD SEE AN INCREASE IN SUNSHINE ONCE
MORE AS THE COLDEST AIR ALOFT IS QUICKLY SHUNTED OFF TO THE EAST AS
A FLATTER AND FASTER PATTERN TAKES SHAPE IN THE UPPER LEVELS AND
SURFACE RIDING BEGINS TO CREEP IN ACROSS THE AREA FROM THE UPPER
MIDWEST. A FAST-MOVING SHORTWAVE SHOULD BRING SOME CLOUD COVER TO
THE SOUTHERN TIER WEDNESDAY NIGHT BUT HAVE LITTLE OTHER IMPACT
OWING TO A DEARTH OF MOISTURE. LOWS ONCE AGAIN WILL RUN IN THE
40S...WITH A FEW UPPER 30S IN THE SOUTHERN TIER. IT NOW APPEARS THAT
THERE SHOULD BE ENOUGH OF A BREEZE BOTH TUESDAY AND WEDNESDAY NIGHTS
TO PRECLUDE THE DEVELOPMENT OF FROST IN THE SOUTHERN TIER/NORTH
COUNTRY IN SPITE OF TEMPERATURES THAT WILL BE DIPPING INTO THE 30S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
IT WILL BE A DRY DAY ON THURSDAY WITH PASSING HIGH CLOUDS AS THE
REGION WILL REMAIN UNDERNEATH THE FLATTENED BASE OF A DEEP UPPER
LEVEL LOW CENTERED NEAR JAMES BAY. THE UPPER LEVEL FLOW WILL AMPLIFY
ONCE MORE ACROSS THE AREA ON FRIDAY AS A JET MAX DROPS INTO THE BASE
OF THE TROUGH OVER NORTHEASTERN ONTARIO. THIS WILL HELP PUSH ANOTHER
WEAK COLD FRONT ACROSS UPSTATE AND WESTERN NEW YORK ON
FRIDAY...POTENTIALLY TRIGGERING A SHOWER OR TWO ACROSS THE NORTH
COUNTRY. HOWEVER...A LACK OF MOISTURE WILL ONCE AGAIN LIMIT POPS TO
A SLIGHT CHANCE AT BEST.
AN EVEN MORE BENIGN PATTERN TAKES SHAPE FOR THE COMING WEEKEND AS
SURFACE HIGH PRESSURE TRACKS OVER THE LOWER GREAT LAKES. THERE WILL
BE PLENTY OF SUNSHINE TO BE HAD FRIDAY AND SATURDAY AS THE HIGH
MOVES OVERHEAD BEFORE MOVING OFF THE EAST COAST SUNDAY. AS THE HIGH
MOVES OFF THE EAST COAST...LOOK FOR RETURN FLOW TO SET UP ACROSS THE
LOWER GREAT LAKES THAT WILL SIGNAL A RETURN TO WARMER CONDITIONS
SUNDAY WITH UNSETTLED WEATHER LIKELY TO FOLLOW BY MONDAY AS A WARM
FRONT LIFTS NORTH ACROSS THE GREAT LAKES.
REGARDING TEMPERATURES...READINGS WILL RUN IN THE 60S ON THURSDAY.
WHILE CERTAINLY WARMER THAN THE CHILLY 50S EXPECTED WEDNESDAY...THE
LOWER GREAT LAKES REGION WILL REMAIN CLOSE ENOUGH TO THE
AFOREMENTIONED UPPER LEVEL LOW TO KEEP TEMPERATURES A FEW DEGREES
BELOW NORMAL. INDEED THE PASSAGE OF THE WEAK COOL FRONT FRIDAY WILL
KNOCK TEMPS BACK A COUPLE OF DEGREES. WITH HIGH PRESSURE MOVING
BUILDING FRIDAY NIGHT AND COOL/DRY AIR IN PLACE...WE SHOULD SEE A
CHILLY NIGHT WITH LOWS IN THE LOW/MID 40S...WITH UPPER 30S IN THE
SOUTHERN TIER AND NORTH COUNTRY. THIS TIME WINDS MAY BE LIGHT ENOUGH
TO POTENTIALLY ALLOW FOR FROST ACROSS THE SHELTERED AREAS OF THE
NORTH COUNTRY AND THE SOUTHERN TIER. THEREAFTER...TEMPERATURES
SHOULD GRADUALLY REBOUND THROUGH THE WEEKEND AS THE HIGH DRIFTS EAST
OF THE REGION AND RETURN FLOW TAKES HOLD WITH WIDESPREAD 70S
EXPECTED ONCE AGAIN BY SUNDAY.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS IN PLACE EARLY THIS MORNING EXCEPT FOR SOME IFR FOG
ACROSS THE HILLTOPS OF THE SOUTHERN TIER. THIS WILL WILL DISSIPATE
IN THE MORNING WITH INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS
DURING THE LATE MORNING AND AFTERNOON AS A PRE-FRONTAL TROUGH
CROSSES THE FORECAST AREA. A STABLE FLOW OFF LAKE ERIE SHOULD KEEP
KBUF/KIAG FREE FROM ANY HEAVY STORMS WHICH WILL DEVELOP FROM THE
SOUTHERN TIER TO EAST OF BUFFALO TO ROCHESTER AND SYRACUSE. STORM
ACTIVITY WILL SHIFT EAST LATER THIS EVENING WITH MAINLY DRY
CONDITIONS EXPECTED TONIGHT.
OUTLOOK...
TUESDAY THROUGH FRIDAY...VFR.
&&
.MARINE...
LIGHT WINDS AND MINIMAL WAVES WILL CONTINUE ON THE EASTERN GREAT
LAKES TODAY WITH AREAS OF FOG AS A WARM AND HUMID AIRMASS REMAINS
OVER THE COOL LAKE WATERS. CONDITIONS ON THE LAKES SHOULD REMAIN
QUIET OUTSIDE OF ANY THUNDERSTORMS PRODUCING ASSOCIATED HIGHER WINDS
AND WAVES.
A COLD FRONT WILL SWEEP ACROSS THE EASTERN GREAT LAKES LATE
TONIGHT/TUESDAY WITH AN INCREASE IN WIND SPEED AND WAVE ACTION INTO
TUESDAY. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE LAKE ERIE
NEARSHORES COVERING TUESDAY AFTERNOON/EVENING. HIGH PRESSURE WILL
THEN BUILD OVER THE EASTERN GREAT LAKES WEDNESDAY THROUGH THE REST
OF THE WEEK WITH LOW WIND AND WAVE ACTION.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TO 11 PM EDT TUESDAY FOR LEZ040-
041.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...WOOD
LONG TERM...WOOD
AVIATION...SMITH
MARINE...SMITH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
444 AM EDT MON MAY 18 2015
.SYNOPSIS...
A WARM AND HUMID AIR MASS WILL REMAIN OVER THE REGION WITH A PERIOD
OF SHOWERS AND THUNDERSTORMS PUSHING ACROSS WESTERN AND CENTRAL NEW
YORK TODAY AHEAD OF A COLD FRONT. SOME OF THESE THUNDERSTORMS MAY
BRING LOCALIZED HEAVY RAIN. THE FRONT WILL CROSS EARLY TUESDAY THEN
A COOLER AND DRIER AIRMASS WILL ARRIVE BEHIND THE FRONT FOR THE
REMAINDER OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE FORECAST AREA LIES BENEATH AN AMPLIFIED 500MB RIDGE THIS MORNING
WITH STACKED SURFACE AND UPPER LEVEL LOW OVER NORTHERN MINNESOTA
CONTINUING TO SPREAD WARM AND MOIST AIR NORTH ACROSS THE GREAT
LAKES. DEWPOINTS RUNNING CLOSE TO 60F ACROSS WESTERN NEW YORK WITH
MID 60S DEWPOINTS FOUND ACROSS MICHIGAN. SPC MESOSCALE ANALYSIS
SHOWS A RIBBON OF HIGH PRECIPITABLE WATER VALUES AROUND 1.7 INCHES
RUNNING FROM NORTH OF GEORGIAN BAY TO LAKE ERIE. PLENTY OF MOISTURE
TO BE FOUND SO FOCUS FOR TIMING OF SHOWER AND THUNDERSTORM ACTIVITY
TODAY WILL BE ON ANY SYNOPTIC/MESOSCALE FEATURES SHIFTING ACROSS
THE EASTERN GREAT LAKES.
A PRE-FRONTAL TROUGH IS ANALYZED ROUGHLY FROM NORTHERN MI SOUTHEAST
TO NEAR KERI. THIS IS FORECAST TO SHIFT ACROSS WESTERN AND CENTRAL
NEW YORK TODAY. LOOKING TO THE MID-LEVELS...FORCING MAY ALSO COME
FROM ANY SUBTLE SHORTWAVES ROLLING UP THE WEST SIDE OF THE RIDGE
AXIS FROM THE MISS VALLEY TOWARD THE EASTERN GREAT LAKES. MESOSCALE
GUIDANCE SUCH AS WRF AND HRRR MODELS SUGGEST A FEW ISOLATED SHOWERS
AND STORMS MAY WORK INTO WNY ALONG THE TROUGH THIS MORNING. BY EARLY
AFTERNOON FORECAST CAPE OF 2-3K J/KG WILL FEED MORE NUMEROUS SHOWERS
AND THUNDERSTORMS DEVELOPING FROM THE SOUTHERN TIER ACROSS THE
GENESEE VALLEY AND FINGER LAKES. A STABLE SOUTHWEST FLOW OFF LAKE
ERIE SHOULD KEEP MUCH OF THE NIAGARA FRONTIER PROTECTED FROM THE
HEAVIER STORMS BUT LAKE BREEZES COULD TRIGGER ADDITIONAL CELLS TO THE
SOUTH AND EAST OF BUFFALO. BULK SHEAR THIS AFTERNOON IS FORECAST
ONLY AROUND 15 KTS SO TOO WEAK TO SUPPORT ANY SIGNIFICANT WIND/HAIL
THREAT. THE DEEP MOISTURE IN PLACE PER PWATS AND SKINNY CAPE
PROFILES WITH SLOW STORM MOTIONS WILL HOWEVER BRING A RISK FOR
LOCALLY HEAVY RAIN AND FLOODING IF ANY TRAINING CELLS DEVELOPS.
TONIGHT...THE SURFACE LOW WILL SHIFT NORTH OF THE GREAT LAKES TO
SOUTHERN QUEBEC. NEAR-TERM MODELS INDICATE THE MAJORITY OF REMAINING
CONVECTION WILL BE LIMITED FROM THE FINGER LAKES EASTWARD ACROSS
CENTRAL AND EASTERN NEW YORK. WESTERN NEW YORK WILL LARGELY REMAIN
DRY. THE COLD FRONT WILL CROSS WNY LATE TONIGHT AND IS FORECAST TO
BE NEAR THE FINGER LAKES BY 12Z TUESDAY WITH SKY COVER THINNING FROM
WEST TO EAST. THE OVERNIGHT TIMING OF THE FRONT SHOULD LIMIT A
SECOND ROUND OF SHOWER/TSTM ACTIVITY.
TEMPERATURES TODAY WILL AGAIN RISE ABOVE NORMAL WITHIN A HUMID
AIRMASS. 850MB TEMPS OF NEAR +15C WILL SUPPORT SURFACE HIGH TEMPS
RANGING FROM THE UPPER 70S TO MID 80S. THE U70S TEMPS WILL ONLY BE
LIMITED BY EARLIER START TO CONVECTION WHILE MORE HEATING ACROSS
FINGER LAKES AND NORTH COUNTRY WILL HELP BOOST TEMPS TO THE M80S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
A STRONG COLD FRONT WILL CROSS THE FORECAST AREA DURING THE DAY ON
TUESDAY. WHILE THE BULK OF THE PRECIPITATION WILL BE ASSOCIATED WITH
THE PRE-FRONTAL TROUGH AND ALREADY WELL TO THE EAST OF THE FORECAST
AREA OVER THE ADIRONDACKS/GREEN MOUNTAINS BY TUESDAY MORNING...A FEW
SHOWERS WILL STILL BE POSSIBLE ALONG/JUST AHEAD OF THE COLD
FRONT...PARTICULARLY ACROSS THE NORTH COUNTRY WHERE THE APPROACH OF
THE COLD FRONT WILL COINCIDE WITH THE AFTERNOON DIURNAL HEATING
MAXIMUM.
OTHERWISE...LOOK FOR BREEZY CONDITIONS WITH FALLING TEMPERATURES
BEHIND THE COLD FRONT. A PERIOD OF POST-FRONTAL SUBSIDENCE AND
SUNSHINE WILL GIVE WAY TO INCREASING CLOUDS LATER IN THE DAY AND
INTO THE EVENING AS THE UPPER LEVEL TROUGH SWINGS THROUGH.
TEMPERATURES WILL CONTINUE TO FALL INTO THE 40S TUESDAY NIGHT...WITH
HIGHER ELEVATIONS DIPPING JUST BELOW THE 40 DEGREE MARK AS THE CORE
OF THE COLD AIR ALOFT MOVES ACROSS THE REGION. WITH 850MB TEMPS
FALLING BELOW -2C...WE MAY EVEN SEE A DECENT AMOUNT OF LAKE-ENHANCED
CLOUD COVER TUESDAY NIGHT AND INTO WEDNESDAY MORNING. THIS COLD AIR
ALOFT AND THE ASSOCIATED CLOUD COVER WILL AID IN MAKING WEDNESDAY
THE COLDEST DAY OF THIS WEEK WITH HIGHS ONLY TOPPING OUT IN THE LOW
TO MID 50S.
BY WEDNESDAY AFTERNOON WE SHOULD SEE AN INCREASE IN SUNSHINE ONCE
MORE AS THE COLDEST AIR ALOFT IS QUICKLY SHUNTED OFF TO THE EAST AS
A FLATTER AND FASTER PATTERN TAKES SHAPE IN THE UPPER LEVELS AND
SURFACE RIDING BEGINS TO CREEP IN ACROSS THE AREA FROM THE UPPER
MIDWEST. A FAST-MOVING SHORTWAVE SHOULD BRING SOME CLOUD COVER TO
THE SOUTHERN TIER WEDNESDAY NIGHT BUT HAVE LITTLE OTHER IMPACT
OWING TO A DEARTH OF MOISTURE. LOWS ONCE AGAIN WILL RUN IN THE
40S...WITH A FEW UPPER 30S IN THE SOUTHERN TIER. IT NOW APPEARS THAT
THERE SHOULD BE ENOUGH OF A BREEZE BOTH TUESDAY AND WEDNESDAY NIGHTS
TO PRECLUDE THE DEVELOPMENT OF FROST IN THE SOUTHERN TIER/NORTH
COUNTRY IN SPITE OF TEMPERATURES THAT WILL BE DIPPING INTO THE 30S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
THURSDAY AND FRIDAY...BROAD/FLAT UPPER LEVEL TROUGHING OVER THE
GREAT LAKES AND NORTHEAST WILL REAMPLIFY AS A PAIR OF SHORTWAVES
DROP THROUGH ITS BACKSIDE AND BASE...WITH AN ATTENDANT SECONDARY
COLD FRONT PIVOTING ACROSS OUR REGION BETWEEN THURSDAY NIGHT AND
FRIDAY. AT THIS JUNCTURE...THIS LATTER FEATURE STILL APPEARS TO BE
TOO WEAK AND STARVED FOR BOTH MOISTURE AND UPPER LEVEL SUPPORT TO
WARRANT THE INCLUSION OF ANY PRECIP CHANCES IN THE FORECAST...SO
HAVE CONTINUED TO LEAVE THINGS DRY WITH SURFACE HIGH PRESSURE AND
DRIER AIR CONTINUING TO DOMINATE OUR WEATHER. IN ADVANCE OF THE
AFOREMENTIONED FRONT...SOME MODEST WARMING OF OUR AIRMASS SHOULD
ALLOW TEMPS TO RECOVER BACK INTO THE LOWER AND MID 60S ON
THURSDAY...BEFORE PULLING BACK AT LEAST A LITTLE BEHIND THE
BOUNDARY ON FRIDAY.
NEXT WEEKEND...SPRAWLING HIGH PRESSURE AND DRY AIR OVER OUR
REGION AT THE START OF SATURDAY WILL SLOWLY DRIFT EASTWARD AND OFF
THE ATLANTIC COASTLINE...WHILE HEIGHTS ALOFT ALSO REBUILD AS THE
UPPER LEVEL TROUGH OVER OUR REGION LIFTS OUT...AND THE NEXT MODEST
TROUGH BEGINS SLIDING EASTWARD ACROSS THE PLAINS STATES. UNDER
THIS REGIME...DRY WEATHER SHOULD PERSIST THROUGH AT LEAST THE
FIRST HALF OF SUNDAY...BEFORE AN APPROACHING WARM FRONT OVER THE
OHIO VALLEY POTENTIALLY BRINGS A RISK OF SHOWERS SUNDAY AFTERNOON.
THIS STATED...HAVE ELECTED TO KEEP THINGS DRY ON SUNDAY FOR NOW
GIVEN BOTH THE DISTANT VANTAGE POINT AND THE LACK OF AGREEMENT
EXHIBITED BY THE MEDIUM RANGE GUIDANCE WITH RESPECT TO THE TIMING
OF THE WARM FRONT...WHICH IS TYPICAL FOR THIS FAR IN ADVANCE. WHAT
IS MORE CERTAIN IS THAT THIS PATTERN SHOULD ALLOW FOR A WARMING
TREND...WITH DAYTIME HIGHS CLIMBING BACK INTO THE 70S BY NEXT
SUNDAY.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS IN PLACE EARLY THIS MORNING EXCEPT FOR SOME IFR FOG
ACROSS THE HILLTOPS OF THE SOUTHERN TIER. THIS WILL WILL DISSIPATE
IN THE MORNING WITH INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS
DURING THE LATE MORNING AND AFTERNOON AS A PRE-FRONTAL TROUGH
CROSSES THE FORECAST AREA. A STABLE FLOW OFF LAKE ERIE SHOULD KEEP
KBUF/KIAG FREE FROM ANY HEAVY STORMS WHICH WILL DEVELOP FROM THE
SOUTHERN TIER TO EAST OF BUFFALO TO ROCHESTER AND SYRACUSE. STORM
ACTIVITY WILL SHIFT EAST LATER THIS EVENING WITH MAINLY DRY
CONDITIONS EXPECTED TONIGHT.
OUTLOOK...
TUESDAY THROUGH FRIDAY...VFR.
&&
.MARINE...
LIGHT WINDS AND MINIMAL WAVES WILL CONTINUE ON THE EASTERN GREAT
LAKES TODAY WITH AREAS OF FOG AS A WARM AND HUMID AIRMASS REMAINS
OVER THE COOL LAKE WATERS. CONDITIONS ON THE LAKES SHOULD REMAIN
QUIET OUTSIDE OF ANY THUNDERSTORMS PRODUCING ASSOCIATED HIGHER WINDS
AND WAVES.
A COLD FRONT WILL SWEEP ACROSS THE EASTERN GREAT LAKES LATE
TONIGHT/TUESDAY WITH AN INCREASE IN WIND SPEED AND WAVE ACTION INTO
TUESDAY. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE LAKE ERIE
NEARSHORES COVERING TUESDAY AFTERNOON/EVENING. HIGH PRESSURE WILL
THEN BUILD OVER THE EASTERN GREAT LAKES WEDNESDAY THROUGH THE REST
OF THE WEEK WITH LOW WIND AND WAVE ACTION.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TO 11 PM EDT TUESDAY FOR LEZ040-
041.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...WOOD
LONG TERM...JJR
AVIATION...SMITH
MARINE...SMITH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
110 AM CDT MON MAY 18 2015
.UPDATE...
ISSUED AT 109 AM CDT MON MAY 18 2015
ROLLA SUSTAINED WIND AT 37 MPH GUSTING TO 48 MPH AND TURTLE MOUNTAIN
RAWS AT 37 MPH WITH GUSTS TO 57 MPH. THESE VALUES ARE JUST BELOW
HIGH WIND WARNING CRITERIA...AND LOOKING AT THE DECREASING TREND
EXPECTED DURING THE OVERNIGHT HOURS - WILL ALLOW THE HIGH WIND
WARNING FOR ROLETTE AND PIERCE COUNTIES TO EXPIRE. THE STRONG WINDS
ARE IN THE WORDING OF THE WINTER WEATHER ADVISORY THAT IS IN EFFECT
FOR NORTH CENTRAL NORTH DAKOTA - INCLUDING ROLETTE AND PIERCE
COUNTIES. THIS IS IN EFFECT UNTIL 7 AM CDT MONDAY...AND FOR NOW WILL
KEEP THE ADVISORY GOING. PRECIPITATION TRENDS ON REGIONAL RADARS
INDICATE DECREASE IN AREAL COVERAGE AND INTENSITY. SHOULD THIS TREND
CONTINUE THE WINTER WEATHER ADVISORY MAY BE DROPPED/ENDED BEFORE
DAYBREAK. WILL WAIT A FEW HOURS FOR THAT DECISION.
OTHERWISE WINDS ON TRACK WITH THE WIND ADVISORY GOING UNTIL 7
AM...AND WILL RE-EVALUATE IN A FEW HOURS. REST OF FORECAST ELEMENTS
ON TRACK FOR THIS UPDATE.
UPDATE
ISSUED AT 1042 PM CDT SUN MAY 17 2015
ROLLA STILL SUSTAINED AT OVER 40KTS WITH TURTLE MOUNTAIN RAWS
STILL GUSTING TO 61 MPH. WILL EXTEND THE HIGH WIND WARNING A
COUPLE OF HOURS...TILL 1AM CDT. RAP PRESSURE RISES ON THE DECREASE
SO A 1AM EXPIRATION SHOULD BE GOOD.
UPDATE
ISSUED AT 1004 PM CDT SUN MAY 17 2015
HEADLINES WILL REMAIN AS IS. AN ARGUMENT CAN BE MADE FOR A SMALL
AREA FOR BLIZZARD HEADLINES WITH BOTH ROLLA AND HARVEY REPORTING
STRONG WINDS GUSTING 35-45KTS AND 1/4 MILE VIS IN HEAVY SNOW.
HOWEVER...VIS HAVE BEEN JUMPING FROM 1/4 TO 3/4 AND DO NOT FEEL
THE SMALL AREA AND TIME DURATION JUSTIFIES AN UPGRADE. THUS WILL
MAINTAIN THE WINTER WEATHER ADVISORY AS IS WITH NEAR BLIZZARD
WORDING AND OTHER DIRE TERMINOLOGY IN THE OVERVIEW AND SEGMENT.
HIGH WIND WARNING OVER MY FAR NORTHEAST EXPIRES AT 11PM. WILL
REVISIT IN 30-45 MIN FOR A POSSIBLE EXTENSION.
UPDATE
ISSUED AT 710 PM CDT SUN MAY 17 2015
RAIN CHANGING OVER TO SNOW AS TEMPERATURES AT THE SURFACE AND
ALOFT COOL. HAVE HAD A MIX OF SLEET SOUTH CENTRAL WHERE SOUNDINGS
INDICATE A WARM LAYER ALOFT...COLD LAYER AROUND 850MB...AND
SURFACE TEMPERATURES IN THE MIDDLE 30S. THE WARM LAYER WILL COOL
WITH ALL SNOW BY 01-02Z.
HEADLINES ALL STILL VALID...AND WILL STAY THE COURSE WITH THIS
UPDATE.
UPDATE ISSUED AT 608 PM CDT SUN MAY 17 2015
OPTED TO ISSUE A HIGH WIND WARNING OVER ROLETTE AND PIERCE
COUNTIES. WINDS CONTINUE TO GUST OVER 60 MPH AT OBSERVING SITES
ACROSS MY FAR NORTHEAST. CANNOT IGNORE THIS SO WENT WITH A
WARNING. OTHER EDITS MINOR FOR NOW...ANOTHER UPDATE OUT BY 0030Z.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 330 PM CDT SUN MAY 17 2015
SIGNIFICANT STORM IMPACTING NORTH DAKOTA WILL BEGIN TO WANE
TONIGHT AND EXIT THE REGION ON MONDAY. AS COLDER AIR WRAPS UP
INTO THE SYSTEM SNOW WILL START TO ACCUMULATE ACROSS THE NORTH
CENTRAL...WITH 2 TO NEAR 6 INCHES EXPECTED. STRONG WINDS WILL
CONTINUE THROUGH THE NIGHT. WILL KEEP WIND ADVISORY THROUGH 7 PM
NORTH CENTRAL THEN TRANSITION TO A WINTER WEATHER ADVISORY FOR
THE SNOW AND MENTION THE STRONG WINDS IN THE WINTER WEATHER
ADVISORY. WILL MAINTAIN WIND ADVISORY THROUGH THE NIGHT SOUTH
CENTRAL.
THE RAIN WILL SIGNIFICANTLY DECREASE AFTER MIDNIGHT. UNTIL THEN
THERE IS A FLOOD ADVISORY FOR EAST CENTRAL NORTH DAKOTA WHERE
WIDESPREAD WARM CONVEYER BELT PRECIP HAS BEEN QUASI STATIONARY
TODAY.
FINALLY...WIDESPREAD FREEZING TEMPERATURES ARE EXPECTED ACROSS WEST
AND CENTRAL NORTH DAKOTA TONIGHT. WILL LET THE WINTER WEATHER
ADVISORY AND ITS SNOW AMOUNTS STAND IN FOR THE FREEZE WARNING
NORTH CENTRAL. ACROSS THE WEST AND SOUTH WILL ISSUE A FREEZE
WARNING TONIGHT AND EARLY MONDAY.
MONDAY WILL BECOME SUNNY WITH DIMINISHING WINDS.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 330 PM CDT SUN MAY 17 2015
COOL AND DRY WILL CHARACTERIZE THE LONG TERM.
HIGH PRESSURE WILL BUILD IN BEHIND THE DEPARTING WEEKEND STORM
MONDAY NIGHT. THIS WILL LEAD TO CLEAR SKIES AND LIGHT WIND.
TEMPERATURES OVERNIGHT WILL LIKELY FALL INTO THE MID 20S FOR MOST
OF NORTH DAKOTA. A FREEZE WARNING WILL BE POSSIBLE WITH WIDESPREAD
FROST.
THE REST OF THE WEEK LOOKS DRY WITH SURFACE HIGH PRESSURE
REMAINING ENTRENCHED OVER NORTH DAKOTA AND UPPER LEVEL RIDING
BUILDING WEST. THIS WILL KEEP MOST OF THE MOISTURE AND STORM
TRACKS THIS WEEK SOUTH OF NORTH DAKOTA.
TEMPERATURES LOOK TO REBOUND INTO THE 60S BY THURSDAY.
THE NEXT CHANCE FOR PRECIPITATION ARRIVES THIS WEEKEND AS THE
RIDGE BREAKS DOWN AND AN UPPER LEVEL LOW MOVES INTO THE PLAINS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 109 AM CDT MON MAY 18 2015
VFR AT KISN SHOULD PREVAIL THROUGH THE TAF PERIOD. KDIK SHOULD BE
IMPROVING BY AROUND 09Z. WIDESPREAD MVFR CONDITIONS IN SNOW AND FOG
AT KMOT/KBIS SHOULD CONTINUE THROUGH AROUND 12Z...THEN IMPROVE TO
VFR. KJMS WILL LIKELY REMAIN AT MVFR AND IFR CONDITIONS UNTIL AROUND
00Z. SNOW SHOULD END AT KJMS BY AROUND 15Z BUT LARGE MVFR CLOUD
SHIELD SHOULD REMAIN EAST OF KMOT/KBIS BUT ENCOMPASS KJMS
THROUGH AROUND 00Z.
&&
.HYDROLOGY...
ISSUED AT 330 PM CDT SUN MAY 17 2015
HAVE ISSUED AN AREAL FLOOD ADVISORY THROUGH THIS EVENING EAST
CENTRAL. RAINFALL AMOUNTS OF TWO TO 4 INCHES WITH SOME ISOLATED
HIGHER AMOUNTS CAUSING PONDING...AND FLOODED FIELDS. CALLS AND
INQUIRIES SO FAR HAVE REVEALED ROADS TO BE OK WITH SOME MINOR
FLOODING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING UNTIL 10 AM CDT /9 AM MDT/ THIS MORNING FOR
NDZ001-009-017>020-031>037-040>048-050-051.
WIND ADVISORY UNTIL 7 AM CDT /6 AM MDT/ THIS MORNING FOR NDZ019-
020-034>037-042-045>048-050-051.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT THIS MORNING FOR
NDZ002>005-010>013-021>023-025.
&&
$$
UPDATE...JV
SHORT TERM...WAA
LONG TERM...AJ
AVIATION...JV
HYDROLOGY...WAA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1135 PM CDT SUN MAY 17 2015
.UPDATE...
ISSUED AT 1135 PM CDT SUN MAY 17 2015
STILL HAVE WINDS NEAR WARNING CRITERIA WITHIN THE DEVILS LAKE
BASIN...BUT MODEL GUIDANCE INDICATES 925MB WIND SPEEDS DECREASING
10 KNOTS FROM 03Z TO 06Z...SO ALLOWED HIGH WIND WARNING TO EXPIRE
AT 11PM. WILL NEED TO WATCH THE NORTHERN VALLEY WITH DUE NORTH
WINDS AND THE RAP INDICATING INCREASING 925MB WIND SPEEDS. GRAFTON
AWOS IS CLOSE TO WARNING CRITERIA...AND WITH THE SFC PRESSURE
GRADIENT STILL TIGHTENING CANNOT RULE OUT STRONG WINDS HERE.
OTHERWISE...WINTER WEATHER ADVISORY AREA HAS REPORTS OF SNOW AND
SLEET AND SLICK ROADS. ALSO HAD A REPORT OF 2.5 INCHES OF SNOW
JUST N/NE OF ROLLA (IN CANADA). IMAGINE THAT THERE IS SOME SLUSHY
ACCUMULATION INTO THE STATES.
ELSEWHERE...RAIN HAS REDEVELOPED AS EXPECTED ACROSS NW MN (EVEN
INTO THE VALLEY).
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 337 PM CDT SUN MAY 17 2015
FIRST OFF...SFC LOW NEAR SISSETON/WAHPETON AREA AT MID AFTN AND
SFC PRESSURE FALLS ARE NOT CENTERED NEAR FOSSTON MN. SO SFC LOW
WILL TACK NORTHEAST TOWARD THAT AREA THIS EVENING. EAST OF SFC LOW
AREA IN DRY SLOT WHERE HEATING OCCURRED FAVORABLE FOR SOME
THUNDERSTORM TO FORM. FOCUS IS FROM ALEXANDRIA NORTH TO EAST OF
FERGUS FALLS....TO BEMIDJI...PARK RAPIDS AND WADENA. SFC AND UPPER
AIR LOW PLACEMENT FAVORS LOW TOPPED SUPERCELLS WITH POSSIBLE
FUNNEL FORMATION. PER SPC NOT EXPECTING WIDESPREAD STORMS THIS
STRONG....BUT COULD BE THRU 00Z. ANOTHER QUESTION IS NW EDGE OF
DEF ZONE PRECIP. RAIN FALLING PER PUBLIC LANGDON-DEVILS LAKE AREA
STILL. MODELS TAKE DRIER AIR WEST AND WANT TO SHUT OFF DEF ZONE
HEAVY PRECIP THIS EVENING LEAVING LIGHT PRECIP OVERNIGHT INTO
MONDAY MORNING IN THE COLD AIR WHERE IT WILL BE COLD ENOUGH FOR
SNOW. SO JUST HOW MUCH SNOW WILL FALL IS QUESTIONABLE. WILL LEAVE
WSW OUT FOR 1-3 INCHES IN DVL BASIN-LANGDON AREAS OVERNIGHT AS TOO
UNCERTAIN TO TINKER WITH IT.
WINDS WILL BE A BIG FACTOR AND CONTINUE TO GUST IN THE 40-55 MPH
RANGE IN DVL BASIN AND SPREAD INTO THE RRV THIS EVE. STRONG WINDS
OVERNIGHT INTO MONDAY MORNING SO HAVE WIND ADVISORIES OUT.
MOVED PRECIP OUT A BIT FASTER THAN EARLIER FCSTS MONDAY. OTHERWISE
COLD AND WINDY. CLEARING OVERSPREADS AREA MON NIGHT AND LIKELY
FREEZE CONDITIONS IN MANY AREAS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 337 PM CDT SUN MAY 17 2015
WELCOME DRY WEATHER TUESDAY AND WEDNESDAY AS HIGH PRESSURE MOVES
IN AND TEMPS BEGIN TO RECOVER.
FOR WED NIGHT THROUGH SUNDAY...SMALL DISCUSSION TODAY DUE TO SEVERE
WEATHER POTENTIAL. BASICALLY KEPT THE THU/FRI PERIOD DRY AND LEFT
PCPN CHANCES AS THEY WERE FOR SAT/SUN. TEMPS LOOK TO RETURN TO NEAR
NORMAL VALUES.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1135 PM CDT SUN MAY 17 2015
LIFR/IFR CONDITIONS WILL CONTINUE THROUGH THE OVERNIGHT
HOURS...WITH CONDITIONS GRADUALLY IMPROVING ON MONDAY. STRONG
NORTH WINDS ALONG AND WEST OF THE VALLEY WILL GRADUALLY DIMINISH
ON MONDAY.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR NDZ008-016-026>030-038-
039-049-052>054.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT MONDAY FOR NDZ006-007-014-
015-024.
MN...WIND ADVISORY UNTIL 1 PM CDT MONDAY FOR MNZ001>004-007-029.
&&
$$
UPDATE...TG
SHORT TERM...RIDDLE
LONG TERM...GODON/RIDDLE
AVIATION...TG
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
213 AM EDT MON MAY 18 2015
.SYNOPSIS...
WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT
IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD
FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST RADAR MOSAIC AND SURFACE OBSERVATIONS SUGGEST REGION IS
GENERALLY DRY AT THIS TIME. EXPECT THESE CONDITIONS WILL CONTINUE
THROUGH THE OVERNIGHT HOURS...AND HAVE SLIGHT CHANCE POPS CONTINUING.
LATEST HRRR SHOWS A SMALL AREA OF SHOWERS...CURRENTLY OVER SOUTHEAST
KENTUCKY...WILL SPREAD NORTHEAST AND INCREASE IN AREAL COVERAGE AS
IT MOVES INTO OUR SOUTHERN COUNTIES LATER THIS MORNING. THE CURRENT
TREND OF THESE SHOWERS HAS BEEN TO WEAKEN. SO NOT SURE HOW MUCH OF
THESE SHOWERS WILL ACTUALLY MAKE IT INTO OUR AREA.
MOST OF THE MODELS THEN INDICATE WEAK DISTURBANCES WILL MOVE ACROSS
THE AREA TODAY INTO TONIGHT. COMBINATION OF THESE DISTURBANCES AND
INCREASING INSTABILITY SHOULD ONCE AGAIN RESULT IN THE DEVELOPMENT
OF SHOWERS AND STORMS TODAY.
LOCALIZED DOWNPOURS ARE ONCE AGAIN POSSIBLE TODAY AND TONIGHT...AND
CAN RESULT IN MINOR FLOODING OF STREETS...CREEKS...LOW LYING AND
POOR DRAINAGE AREAS.
WITH THE LOSS OF DAYTIME HEATING...THE COVERAGE AND INTENSITY OF
THE CONVECTION SHOULD BEGIN TO WANE. HOWEVER...A COLD FRONT...WHICH
IS EXPECTED TO PUSH INTO THE REGION LATE TONIGHT...SHOULD CONTINUE
THE THREAT OF SHOWERS AND STORMS.
CURRENT THINKING IS THAT THE FRONT SHOULD BE LOCATED NEAR OR JUST
EAST OF THE OHIO RIVER AT THE END OF THIS PERIOD.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
MADE NO REAL CHANGES WITH THE SHORT TERM PART OF THE FORECAST.
RAISED POPS A BIT IN THE EAST MONDAY NIGHT AHEAD OF THE COLD
FRONT. PW VALUES ARE IN THE 1.5-1.75 INCHES RANGE AHEAD THE FRONT
SO THE PROSPECT OF HEAVY RAIN OVERNIGHT IS STILL POSSIBLE. EVEN
WITH ALL OF THE RAIN THAT HAS FALLEN UP TO THIS POINT THE GROUND
SHOULD BE ABLE TO HANDLE THE SITUATION SO NO REAL CONCERNS. WILL
CONTINUE TO MONITOR THE SITUATION. IT DRIES OUT QUICKLY BEHIND THE
FRONT STARTING TUESDAY NIGHT.
DRY WEATHER WITH PLEASANT TEMPERATURES SHOULD PREVAIL TUESDAY
NIGHT AND WEDNESDAY AS WEAK HIGH PRESSURE BUILDS TO THE WEST
GIVING ZONAL FLOW FOR THE OHIO VALLEY.
WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE
PERIOD.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
NOTHING SIGNIFICANT TO FOCUS ON IN THE LONG TERM. HIGH PRESSURE
BUILDS OVER THE CENTRAL US AND THAT WILL LEAVE ZONAL FLOW OVER THE
OHIO VALLEY. THE EXTENDED FORECAST WILL BE DRY FOR THE MOST PART
BUT CONFIDENCE IS NOT ALL THAT HIGH AS THERE COULD BE A FEW UPPER
LEVEL RIPPLES CAUSED BY THE WEAK FRONT THAT PASSES TO THE NORTH
NEXT WEEKEND. PRECIPITATION CHANCES INCREASING ON SUNDAY.
WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
06Z MONDAY THRU 06Z TUESDAY...
ALL OF THE SHOWERS AND STORMS HAVE MOVED OUT OF THE REGION...OR
HAVE DISSIPATED. A FEW SHOWERS ARE STILL POSSIBLE DURING THE
OVERNIGHT HOURS.
VFR CONDITIONS PREVAILED IN MOST LOCATIONS. HOWEVER...MVFR/IFR
CONDITIONS WERE OCCURRING ALONG SOME RIVER VALLEYS.
CONDITIONS SHOULD REMAIN ROUGHLY ABOUT THE SAME THRU 12Z...WHEN
CONDITIONS SHOULD IMPROVE AFTER SUNRISE.
SEVERAL DISTURBANCES ARE EXPECTED TO MOVE ACROSS THE AREA
TODAY...WHICH WILL RESULT IN THE REDEVELOPMENT OF SHOWERS AND
THUNDERSTORMS FOR THE AFTERNOON AND EVENING HOURS. WHILE MOST
LOCATIONS WILL SEE VFR OR MVFR CONDITIONS...EXPECT IFR CONDITIONS
ARE POSSIBLE NEAR THE HEAVIER STORMS. GUSTY WINDS ARE ALSO
POSSIBLE NEAR THE STRONGER STORMS.
THE STORMS SHOULD THEN WEAKEN AFTER 23Z. HOWEVER...SCATTERED
STORMS WILL REMAIN POSSIBLE THROUGH THE END OF THE PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: COVERAGE OF FOG REMAINS IN QUESTION OVER
WEST VIRGINIA THROUGH 12Z MON. HIGHLY VARIABLE CONDITIONS IN THE
SHOWERS AND STORMS TODAY WITH CONDITIONS GOING LOWER THAN
FORECAST.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE MON 05/18/15
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY H H L L L L H H H M M H
HTS CONSISTENCY H H H H H H H H H M H H
BKW CONSISTENCY M H H H H H H H H M H H
EKN CONSISTENCY L L L L L L H M H H M M
PKB CONSISTENCY H H H H H H H H M M M H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 06Z TUESDAY...
BRIEF IFR IN SHOWERS AND THUNDERSTORMS POSSIBLE MON NIGHT...AND IN
LOW CLOUDS TUE MORNING. FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT
INTO WED MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/ARJ
NEAR TERM...JSH
SHORT TERM...FB
LONG TERM...FB
AVIATION...JSH
AREA FORECAST DISCUSSION
NWS TULSA OK
1139 PM CDT SUN MAY 17 2015
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
PATCHY FOG STILL EXPECTED LATE TONIGHT AS WINDS SUBSIDE AHEAD OF
COLD FRONT...WHICH WILL MOVE INTO NORTHEAST OKLAHOMA MONDAY
MORNING. THUNDERSTORM CHANCES APPEAR TO LOW AT THIS POINT TO
MENTION ALONG/AHEAD OF FROPA.
&&
.PREV DISCUSSION... /ISSUED 935 PM CDT SUN MAY 17 2015/
DISCUSSION...
A MUCH QUIETER EVENING AS THE AREA HAS REMAINED PRECIP FREE FOR
THE DURATION. BOUNDARY SEPARATING DEW POINTS IN UPPER 60S TO NEAR
70S FROM DRIER AIR EXTENDS FROM SOUTH CENTRAL OK INTO WESTERN
OSAGE COUNTY AND NEAR THIS INTERFACE WITH LIGHT WINDS SOME FOG
DEVELOPMENT REMAINS POSSIBLE. WARM MOIST SECTOR OVER WESTERN OK
AND WESTERN AR REMAINS CAPPED AND SHORT RANGE GUIDANCE INCLUDING
THE 00Z NAM TRENDING TOWARD A DRIER SOLUTION FOR TONIGHT. WILL
KEEP SLIGHT CHANCE ACROSS FAR EASTERN/SOUTHERN AREAS AS A SUBTLE
WAVER MOVES ACROSS TONIGHT AND MAY HAVE JUST ENOUGH LIFT TO SPARK
A FEW SHOWERS LATE TONIGHT OR EARLY MON MORNING. UPDATED PRODUCTS
WILL BE OUT SHORTLY.
PREV DISCUSSION... /ISSUED 634 PM CDT SUN MAY 17 2015/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
SCATTERED TO BROKEN MID/HIGH CLOUDS WILL CONTINUE OVERNIGHT AS
WEAK UPPER DISTURBANCE TRAVERSES THE AREA. COULD SEE SOME
LIGHT FOG TOWARDS MORNING AS WINDS BECOME LIGHT AHEAD OF APPROACHING
FRONTAL BOUNDARY. OTHERWISE...VFR CONDITIONS EXPECTED THROUGH
THE FORECAST PERIOD.
PREV DISCUSSION... /ISSUED 359 PM CDT SUN MAY 17 2015/
DISCUSSION...
NEXT COUPLE OF DAYS MARGINAL CHANCE FOR SHOWERS
THUNDERSTORMS MAINLY SOUTH WHERE BETTER MOISTURE
RESIDES. WRF MODEL AN OUTLIER REGARDING PRECIP
AND POP SOUTHEAST AND NORTHWEST ARKANSAS. DRIER
SHORT TERM HRRR LOOKS GOOD TONIGHT.
NEXT BIG RAIN TUESDAY NIGHT WEDNESDAY WHEN THE
NEXT SHOT OF ENERGY EJECTED FROM THE SOUTHWEST.
CHANCE POPS THURSDAY INTO FRIDAY.
UPPER LOW OVER THE SOUTHWEST FRIDAY MOVES ACROSS
THE ROCKIES AND INTO THE CENTRAL PLAINS...SUNDAY.
ANOTHER SLUG WET WEATHER FOR THE HOLIDAY WEEKEND.
GW
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...12
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1123 PM CDT SUN MAY 17 2015
.UPDATE...
&&
.PREV DISCUSSION... /ISSUED 856 PM CDT SUN MAY 17 2015/
DISCUSSION...WATER VAPOR SATELLITE/WSR-88D VAD WIND PROFILES
INDICATE A MESOSCALE CONVECTIVE VORTEX /MCV/ OVER LOUISIANA. THIS
MCV ALONG WITH A SUBTLE 700 MB SHORTWAVE TROUGH OVER THE LOWER
MISSISSIPPI HAD RESULTED IN ADDITIONAL SHOWERS AND THUNDERSTORMS
DEVELOPING ACROSS THE MID SOUTH THIS EVENING...MAINLY WEST OF THE
MISSISSIPPI RIVER. AS OF 8 PM CDT...TEMPERATURES ACROSS THE
MID SOUTH ARE IN THE LOWER 70S AT MOST LOCATIONS.
LATEST HRRR ALONG WITH THE 00Z WRF INDICATE POTENTIAL FOR RE-
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ACROSS THE MID SOUTH
OVERNIGHT. WILL MAKE SOME ADJUSTMENTS TO POPS AND ALL OTHER
ELEMENTS AS NEEDED FOR THE REMAINDER OF THE NIGHT.
UPDATED GRIDS WILL BE AVAILABLE SHORTLY.
CJC
PREV DISCUSSION... /ISSUED 639 PM CDT SUN MAY 17 2015/
UPDATE...AVIATION DISCUSSION.
PREV DISCUSSION... /ISSUED 304 PM CDT SUN MAY 17 2015/
THE MIDSOUTH REMAINS STUCK UNDERNEATH SOUTHWEST FLOW ALOFT. THE
SOUTHWEST FLOW ALOFT HAS BROUGHT THIS WET PATTERN TO THE REGION AS
THE COMBINATION OF SHORTWAVES MOVING THROUGH THE FLOW AND AN
ABUNDANCE OF MOISTURE FROM THE GULF OF MEXICO HAS PRODUCED ROUND
AFTER ROUND OF SHOWERS AND THUNDERSTORMS.
LOOKING AT LATEST RADAR IMAGES...MOST OF THE SHOWER AND
THUNDERSTORM ACTIVITY HAS NOW PUSHED EAST OF THE MISSISSIPPI
RIVER. MOST OF THIS CONVECTION WILL LIKELY PUSH EAST OF THE CWA BY
7 PM. HOWEVER...LATEST HRRR SHOWS REDEVELOPMENT OCCURRING OVER
NORTHEAST ARKANSAS BY THAT TIME. THE CORRIDOR FROM NORTHEAST
ARKANSAS AND THE MISSOURI BOOTHEEL MAY SEE MOST OF THE CONVECTION
DURING THE LATE EVENING INTO THE OVERNIGHT HOURS BEFORE IT SHIFTS
SOUTHWARD ON MONDAY. HAVE ADJUSTED POPS ACCORDINGLY. IN
ADDITION...SINCE THERE ARE PORTIONS OF NORTHEAST MISSISSIPPI THAT
HAS SEEN SEVERAL ROUNDS OF HEAVY SHOWERS TODAY...WILL GO AHEAD AND
EXPAND THE FLASH FLOOD WATCH SOUTHWARD TO COVER THE ENTIRE CWA
THROUGH MONDAY.
MONDAY WILL BE ANOTHER RAINY DAY FOR THE MIDSOUTH WITH OFF AND ON
PERIODS OF HEAVY SHOWERS AND THUNDERSTORMS. EXPECT HIGHS IN THE
UPPER 70S TO LOWER 80S.
THE COLD FRONT WILL FINALLY BEGIN TO PUSH INTO THE AREA MONDAY
NIGHT INTO TUESDAY. MODELS ARE COMING INTO TO CLOSER AGREEMENT
THAT THE FRONT WILL STALL OUT JUST SOUTH OF THE CWA AND BEGIN
LIFTING BACK NORTHWARD AS A WARM FRONT LATE TUESDAY NIGHT INTO
WEDNESDAY. THIS WILL KEEP SMALL CHANCES FOR SHOWERS AND
THUNDERSTORMS IN THE FORECAST FOR PORTIONS OF EAST-CENTRAL
ARKANSAS AND NORTH MISSISSIPPI WHILE GIVING THE REST OF THE CWA
ONLY A BRIEF REPRIEVE ON TUESDAY NIGHT.
BY WEDNESDAY...THE ENTIRE MIDSOUTH WILL SEE CHANCES FOR SHOWERS
AND THUNDERSTORMS AGAIN AS A WEAK SHORTWAVE MOVES ACROSS THE CWA.
BETTER CHANCES FOR SHOWERS AND THUNDERSTORMS WILL COME WEDNESDAY
NIGHT INTO THURSDAY AS THE FRONT MOVES BACK THROUGH THE AREA AS A
COLD FRONT.
HIGH PRESSURE WILL BUILD INTO THE AREA THURSDAY NIGHT THROUGH
SATURDAY. NO PRECIPITATION IS EXPECTED AS A RESULT. HIGHS WILL BE
IN THE MID 70S TO LOWER 80S. LOWS WILL BE IN THE MID 50S TO LOWER
60S.
LOOKS LIKE THE MIDSOUTH COULD BE UNDERNEATH SOUTHWEST FLOW ALOFT
AGAIN BY SATURDAY NIGHT CONTINUING INTO EARLY NEXT WEEK. THIS
COULD BRING ANOTHER EXTENDED WET PERIOD TO THE REGION.
KRM
&&
.AVIATION...06Z TAFS
MORE OF THE SAME OVER THE NEXT 24 HOURS....ALTHOUGH THIS LOOKS
LIKE THE END OF SEVERAL DAYS OF DEALING WITH STORMS. PERIODS OF
THUNDERSTORMS WILL RESULT IN BRIEF IFR VIS AND VARIABLE GUSTY
WINDS.
THE NEXT ROUND OF THUNDERSTORMS IS DEVELOPING IN SOUTHEAST
ARKANSAS AND NORTHWEST MISSISSIPPI...TRACKING TOWARD THE
NORTHEAST. FEEL CONFIDENT ENOUGH THAT THEY WILL IMPACT MEM AND MKL
TO ADD A PREVAILING THUNDER GROUP FOR A COUPLE OF HOURS STARTING
AT 06 AND 0730Z RESPECTIVELY.
SHORT RANGE MODELS INDICATE ANOTHER YET ROUND OF TSRAS WILL FIRE
UP AFTER MIDNIGHT...SHIFTING ACROSS JBR...MEM...AND MKL PRIOR TO
SUNRISE. MODELS DISAGREE ON HOW WIDESPREAD LOW CLOUDS LATER
TONIGHT AND MON MORNING. BEST CHANCES APPEAR TO BE AT KTUP AND
PLACED A MVFR CIG THERE MONDAY MORNING OTRW WILL GO WITH
OPTIMISTIC FORECAST. ANOTHER ROUND OF DAYTIME HEATING DRIVEN
STORMS IS EXPECTED TOMORROW. WILL CARRY TEMPO VCTS AT ALL SITES
FOR MOST OF THE AFTERNOON.
SOUTH WINDS 10-12 KTS WITH HIGHER GUSTS THIS AFTN...8-10 KTS
TONIGHT. WINDS SHOULD BEGIN TO SHIFT MORE WESTERLY OR
NORTHWESTERLY BY SUNSET TOMORROW...AND PRECIPITATION SHOULD COME
TO AN END AFTER SUNSET.
30
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR CLAY-CRAIGHEAD-
CRITTENDEN-CROSS-GREENE-LAWRENCE-LEE AR-MISSISSIPPI-
PHILLIPS-POINSETT-RANDOLPH-ST. FRANCIS.
MO...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR DUNKLIN-PEMISCOT.
MS...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR ALCORN-BENTON MS-
CALHOUN-CHICKASAW-COAHOMA-DESOTO-ITAWAMBA-LAFAYETTE-LEE MS-
MARSHALL-MONROE-PANOLA-PONTOTOC-PRENTISS-QUITMAN-
TALLAHATCHIE-TATE-TIPPAH-TISHOMINGO-TUNICA-UNION-YALOBUSHA.
TN...FLASH FLOOD WATCH THROUGH MONDAY EVENING FOR BENTON TN-CARROLL-
CHESTER-CROCKETT-DECATUR-DYER-FAYETTE-GIBSON-HARDEMAN-
HARDIN-HAYWOOD-HENDERSON-HENRY-LAKE-LAUDERDALE-MADISON-
MCNAIRY-OBION-SHELBY-TIPTON-WEAKLEY.
&&
$$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
340 AM CDT MON MAY 18 2015
.SHORT TERM...
THE SHORT TERM PERIOD WILL FOCUS ON THE RETURN OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS...THAT COULD COMMENCE AS EARLY
AS LATE THIS AFTN.
THE PACIFIC FRONT/DRYLINE THAT AFFECTED THE SOUTHERN PLAINS
YESTERDAY WAS WELL SOUTH AND EAST OF THE CWA EARLY THIS MORNING...AS
HINTED AT BY DEWPOINTS IN THE 60S AND 70S ACROSS THE CONCHO
VALLEY...BIG COUNTRY AND EDWARDS PLATEAU AREAS. AS SUCH...SOME FOG
AND/OR LOW CLOUDS HAVE DEVELOPED ACROSS PORTIONS OF THE SAID AREAS.
COMPUTER MODELS HINT AT THE BOUNDARY RETREATING TO NEAR THE FAR SRN
SOUTH PLAINS AND LOW ROLLING PLAINS BY AOA DAYBREAK...BRINGING WITH
IT RICH LOW LEVEL MOISTURE AND A CHANCE FOR THE FOG AND/OR STRATUS
DECK TO MAKE HEADWAY TOWARDS THE FA. HOWEVER...MODEL SOLUTIONS SUCH
AS THE HRRR AND THE NAM EXHIBIT THE FOG AND LOW CLOUDS TO STOP JUST
SHORT OF THE FA AND DISSIPATE...GIVEN SFC WINDS VEERING TO THE W-SW
THROUGHOUT DAYBREAK AND THUS MITIGATING THE TRANSPORT OF THE LOW
LEVEL MOISTURE. WE WILL CONTINUE TO MONITOR AND SEE IF THIS DOES
INDEED OCCUR.
ATTENTION WILL TURN TO AN UA LOW THAT WAS IMPINGING ON CNTRL/SRN
CALI PER 07Z SATELLITE WATER VAPOR IMAGERY...AND IS PROGGED TO
TRANSLATE ENE TO NEAR THE FOUR-CORNERS REGION BY TONIGHT. AS
SUCH...SW FLOW ALOFT WILL SHARPEN. EMBEDDED WITHIN THIS SW FLOW IS
AN IMPULSE THAT MODEL SOLUTIONS SHOW EJECTING OUT AHEAD OF THE
PARENT UA LOW...AND NEAR THE SWRN ZONES LATE THIS AFTN/EARLY EVENING
AND PROGRESS TO THE NE TO ACROSS THE NERN ZONES BY TONIGHT. WITH SFC
LEE TROUGHING DEEPENING DUE TO THE APPROACHING UA LOW...THIS WILL
AID TO BACK SFC WINDS TO THE S-SE AND PWATS WILL SOAR INTO THE 1.00-
1.50 INCH RANGE BY TONIGHT...WHILST THE LLJ CRANKS UP TO 20-40 KTS.
WITH ALL THAT SAID...CONVECTION IS STILL EXPECTED TO INITIATE ACROSS
THE FAR SW SOUTH PLAINS AS EARLY AS LATE THIS AFTN/EARLY THIS
EVENING...ESPECIALLY IF THE TIMING OF THE ANTICIPATED EMBEDDED
IMPULSE STAYS TRUE. PRECIP WILL BECOME SCATTERED TO PERHAPS
WIDESPREAD AS IT PROGRESSES NE TO ACROSS THE REMAINDER OF THE CWA
THROUGH THE NIGHT. TO ADD FUEL TO THE PROVERBIAL FIRE...A COLD FRONT
WILL BACKDOOR INTO THE REGION THIS EVENING/TONIGHT...WHICH COULD
SERVE AS ANOTHER FOCUS FOR STORM DEVELOPMENT. WITH SUCH HIGH
PWATS...MODERATE-HEAVY RAINFALL CAN NOT BE RULED OUT WHICH RAISES
CONCERNS FOR LOCALIZED FLOODED. WE ALSO NEED TO KEEP AN EYE OUT FOR
SOME STORMS BECOMING STRONG TO SEVERE...ESPECIALLY ACROSS THE SWRN
ZONES LATE THIS AFTN AS PROGGED MUCAPE VALUES OF 2-3 KJ/KG...30-40
KTS OF 0-6 KM BULK SHEAR...STEEPENED LAPSE RATES AND VEERING WIND
PROFILES SAYS AS MUCH /HAIL AND GUSTY WINDS WILL BE THE PRIMARY
THREATS/.
A SEASONABLY WARM DAY WILL PREVAIL WITH HIGHS IN THE 70S AND
80S...FOLLOWED BY OVERNIGHT LOWS IN THE 50S AND 60S.
.LONG TERM...
THE WEATHER FOR THE PAST SEVERAL WEEKS /MINUS THE WIND AND LACK
OF 70+ DEGREE DEW POINTS/ HAVE MADE IT FEEL LIKE I AM BACK IN MY
OLD STOMPING GROUNDS IN SOUTH MS...AND IT DOESN/T LOOK LIKE THE
PATTERN WILL CHANGE ANY OVER THE NEXT 7 DAYS AND BEYOND. FOR
STARTERS WPC QPF GUIDANCE PRE 00Z SHOWS UPWARDS OF 5 INCHES OF
RAIN OVER THE NEXT 7 DAYS. TUESDAY MORNING WILL START VERY WET
WITH AN UPPER LEVEL LOW WITH A SLIGHT NEG TILT MOVES OVER NV TOWARDS
THE REGION. MODEL OMEGA FIELDS/SOUNDING PROFILES ALL SHOW LIFT AND
NO SUBSIDENCE BY 7AM THOUGH THEY DO VARY ON THE AMOUNT OF LIFT. THE
GFS HAS THE LEAST AMOUNT OF LIFT WITH THE LEAST AMOUNT OF QPF WHILE
THE NAM/ECMWF ARE FAIRLY IN LINE WITH EACH OTHER. PWAT VALUES WILL
BE RELATIVELY HIGH...1.25 TO 1.5 INCHES ON THE CAPROCK WHILE
APPROACHING 2 INCHES ACROSS THE EASTER ROLLING PLAINS. THIS IS IN
PART DUE TO MOIST SURFACE CONDITIONS AS WELL AS A 40KT LLJ PUMPING
IN MOISTURE FROM THE GOMEX. ONE CONCERN WITH TUESDAY MORNING WILL BE
FLOODING. WITH ALREADY SATURATED SOILS AND FULL PLAYA LAKES RUN
OFF...MAINLY IN URBAN AREAS...WILL BE ALL BUT GUARANTEED WITH A
QUICK 1 INCH RAINFALL CAUSING PROBLEMS. WHILE ACTUAL RAINFALL
AMOUNTS AS WELL AS THE LOCATION OF THE HEAVIEST RAIN IS HARD TO
PINPOINT NEARLY 24 HOURS OUT...THE EXPECTED WIDESPREAD DYNAMIC LIFT
IN ADDITION TO THE RICH MOISTURE TRANSPORT VIA THE LLJ SHOWS THAT
HEAVY RAIN MAY BE FAIRLY WIDESPREAD. GIVEN THAT THIS IS EXPECTED TO
HAPPEN DURING THE MORNING TRAFFIC RUSH AN AREAL FLOOD WATCH MAY BE
WARRANTED. FOR NOW WE WILL DEFER THE WATCH DECISION TO THE NEXT
SHIFT FOR FURTHER EVALUATION OF MORE UP TO DATE INFO. THERE IS A
POSSIBLE SEVERE THREAT LATER TOMORROW AFTERNOON/EVENING DEPENDING ON
HOW MUCH SURFACE HEATING CAN BE ACHIEVED. THIS WILL BE DEPENDENT ON
CLOUD COVER. AS OF NOW OUR WESTERN ZONES HAVE SOMEWHAT HIGHER
CHANCES TO SEE SEVERE STORMS THAN THE REST OF THE FA AS CLOUDS WILL
BEGIN TO THIN FROM WEST TO EAST.
WE SHOULD SEE PRECIP MOVE OFF TO THE EAST BY WED MORNING AS A FRONT
APPROACHES FROM THE NORTH. MODEL TIMING WITH THE FROPA DIFFERS WITH
THE GFS /FRONT PUSHING INTO OUR NORTHERN ZONES BY 00Z THURS/ BEING
SLOWER THAN THE ECMWF /FRONT THRU THE FA BY 00Z/. OTHER THAN A WIND
SHIFT AND CLOUD COVER THIS SHOULDN/T CREATE MUCH OF A HEADACHE AS
FAR AS THE FORECAST IS CONCERNED. THE FROPA WILL BE ACCOMPANIED BY A
LOW STRATUS DECK THAT WILL STICK AROUND FOR MUCH OF WED NIGHT INTO
THURS AFTERNOON. RAIN WILL BE POSSIBLE MAINLY DUE TO ISENTROPIC
LIFTING. THE BIGGEST CHANGE TO THE FORECAST DURING THIS PERIOD IS
MAKING THE PRECIP MAINLY IN THE FORM OF RAIN WITH A MENTION OF ISO
THUNDER AS THE CHANCE EXISTS FOR SOME ELEVATED CAPE. ANOTHER LOW IS
PROGGED TO MOVE INLAND ACROSS SOCAL WHICH WILL RETURN SURFACE FLOW
OUT OF THE SOUTH/SOUTHEAST AND SET UP A DRYLINE OVER CENTRAL NM.
THIS WILL BE OUR NEXT BIG RAIN MAKER AS THE DRYLINE PUSHES EASTWARD
AND THEN RETREATS FRIDAY AND SATURDAY.
TEMPS WILL CONTINUE TO REMAIN BELOW SEASONAL AVERAGE AS CLOUD COVER
WILL BE ABUNDANT THRU THE WEEK AND SURFACE MOISTURE WILL HELP
MODERATE SURFACE TEMPS. THURS WILL BE PARTICULARLY CHILLY WITH TEMPS
AVERAGING 20 DEGREES BELOW SEASONAL AVERAGE /MID 60S/ DUE TO SURFACE
CAA ASSOCIATED WITH THE FROPA. ALDRICH
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 78 55 71 49 / 10 80 90 20
TULIA 79 57 69 51 / 10 80 90 40
PLAINVIEW 79 58 70 53 / 10 80 90 40
LEVELLAND 83 60 74 56 / 20 80 90 30
LUBBOCK 83 61 73 57 / 10 80 90 40
DENVER CITY 82 61 76 60 / 30 80 80 20
BROWNFIELD 84 61 74 59 / 20 80 90 30
CHILDRESS 86 63 71 60 / 10 60 90 60
SPUR 84 63 73 61 / 10 70 90 50
ASPERMONT 87 66 75 64 / 10 70 90 50
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
29/51
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
329 AM CDT MON MAY 18 2015
.SHORT TERM...
THE SHORT TERM PERIOD WILL FOCUS ON THE RETURN OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS...THAT COULD COMMENCE AS EARLY
AS LATE THIS AFTN.
THE PACIFIC FRONT/DRYLINE THAT AFFECTED THE SOUTHERN PLAINS
YESTERDAY WAS WELL SOUTH AND EAST OF THE CWA EARLY THIS MORNING...AS
HINTED AT BY DEWPOINTS IN THE 60S AND 70S ACROSS THE CONCHO
VALLEY...BIG COUNTRY AND EDWARDS PLATEAU AREAS. AS SUCH...SOME FOG
AND/OR LOW CLOUDS HAVE DEVELOPED ACROSS PORTIONS OF THE SAID AREAS.
COMPUTER MODELS HINT AT THE BOUNDARY RETREATING TO NEAR THE FAR SRN
SOUTH PLAINS AND LOW ROLLING PLAINS BY AOA DAYBREAK...BRINGING WITH
IT RICH LOW LEVEL MOISTURE AND A CHANCE FOR THE FOG AND/OR STRATUS
DECK TO MAKE HEADWAY TOWARDS THE FA. HOWEVER...MODEL SOLUTIONS SUCH
AS THE HRRR AND THE NAM EXHIBIT THE FOG AND LOW CLOUDS TO STOP JUST
SHORT OF THE FA AND DISSIPATE...GIVEN SFC WINDS VEERING TO THE W-SW
THROUGHOUT DAYBREAK AND THUS MITIGATING THE TRANSPORT OF THE LOW
LEVEL MOISTURE. WE WILL CONTINUE TO MONITOR AND SEE IF THIS DOES
INDEED OCCUR.
ATTENTION WILL TURN TO AN UA LOW THAT WAS IMPINGING ON CNTRL/SRN
CALI PER 07Z SATELLITE WATER VAPOR IMAGERY...AND IS PROGGED TO
TRANSLATE ENE TO NEAR THE FOUR-CORNERS REGION BY TONIGHT. AS
SUCH...SW FLOW ALOFT WILL SHARPEN. EMBEDDED WITHIN THIS SW FLOW IS
AN IMPULSE THAT MODEL SOLUTIONS SHOW EJECTING OUT AHEAD OF THE
PARENT UA LOW...AND NEAR THE SWRN ZONES LATE THIS AFTN/EARLY EVENING
AND PROGRESS TO THE NE TO ACROSS THE NERN ZONES BY TONIGHT. WITH SFC
LEE TROUGHING DEEPENING DUE TO THE APPROACHING UA LOW...THIS WILL
AID TO BACK SFC WINDS TO THE S-SE AND PWATS WILL SOAR INTO THE 1.00-
1.50 INCH RANGE BY TONIGHT...WHILST THE LLJ CRANKS UP TO 20-40 KTS.
WITH ALL THAT SAID...CONVECTION IS STILL EXPECTED TO INITIATE ACROSS
THE FAR SW SOUTH PLAINS AS EARLY AS LATE THIS AFTN/EARLY THIS
EVENING...ESPECIALLY IF THE TIMING OF THE ANTICIPATED EMBEDDED
IMPULSE STAYS TRUE. PRECIP WILL BECOME SCATTERED TO PERHAPS
WIDESPREAD AS IT PROGRESSES NE TO ACROSS THE REMAINDER OF THE CWA
THROUGH THE NIGHT. TO ADD FUEL TO THE PROVERBIAL FIRE...A COLD FRONT
WILL BACKDOOR INTO THE REGION THIS EVENING/TONIGHT...WHICH COULD
SERVE AS ANOTHER FOCUS FOR STORM DEVELOPMENT. WITH SUCH HIGH
PWATS...MODERATE-HEAVY RAINFALL CAN NOT BE RULED OUT WHICH RAISES
CONCERNS FOR LOCALIZED FLOODED. WE ALSO NEED TO KEEP AN EYE OUT FOR
SOME STORMS BECOMING STRONG TO SEVERE...ESPECIALLY ACROSS THE SWRN
ZONES LATE THIS AFTN AS PROGGED MUCAPE VALUES OF 2-3 KJ/KG...30-40
KTS OF 0-6 KM BULK SHEAR...STEEPENED LAPSE RATES AND VEERING WIND
PROFILES SAYS AS MUCH
/HAIL AND GUSTY WINDS WILL BE THE PRIMARY THREATS/.
A SEASONABLY WARM DAY WILL PREVAIL WITH HIGHS IN THE 70S AND
80S...FOLLOWED BY OVERNIGHT LOWS IN THE 50S AND 60S.
.LONG TERM...
THE WEATHER FOR THE PAST SEVERAL WEEKS /MINUS THE WIND AND LACK
OF 70+ DEGREE DEW POINTS/ HAVE MADE IT FEEL LIKE I AM BACK IN MY
OLD STOMPING GROUNDS IN SOUTH MS...AND IT DOESN/T LOOK LIKE THE
PATTERN WILL CHANGE ANY OVER THE NEXT 7 DAYS AND BEYOND. FOR
STARTERS WPC QPF GUIDANCE PRE 00Z SHOWS UPWARDS OF 5 INCHES OF
RAIN OVER THE NEXT 7 DAYS. TUESDAY MORNING WILL START VERY WET
WITH AN UPPER LEVEL LOW WITH A SLIGHT NEG TILT MOVES OVER NV
TOWARDS THE REGION. MODEL OMEGA FIELDS/SOUNDING PROFILES SHOW ALL
LIFT AND NO SUBSIDENCE BY 7AM THOUGH THEY DO VARY ON THE AMOUNT OF
LIFT. THE GFS HAS THE LEAST AMOUNT OF LIFT WITH THE LEAST AMOUNT
OF QPF WHILE THE NAM/ECMWF ARE FAIRLY IN LINE WITH EACH OTHER.
PWAT VALUES WILL BE RELATIVELY HIGH...1.25 TO 1.5 INCHES ON THE
CAPROCK WHILE APPROACHING 2 INCHES ACROSS THE EASTER ROLLING
PLAINS. THIS IS IN PART DUE TO MOIST SURFACE CONDITIONS AS WELL AS
A 40KT LLJ PUMPING IN MOISTURE FROM THE GOMEX. ONE CONCERN WITH
TUESDAY MORNING WILL BE FLOODING. WITH ALREADY SATURATED SOILS AND
FULL PLAYA LAKES RUN OFF...MAINLY IN URBAN AREAS...WILL BE ALL BUT
GUARANTEED WITH A QUICK 1 INCH RAINFALL CAUSING PROBLEMS. WHILE
ACTUAL RAINFALL AMOUNTS AS WELL AS THE LOCATION OF THE HEAVIEST
RAIN IS HARD TO PINPOINT NEARLY 24 HOURS OUT...THE EXPECTED
WIDESPREAD DYNAMIC LIFT IN ADDITION TO THE RICH MOISTURE TRANSPORT
VIA THE LLJ SHOWS THAT HEAVY RAIN MAY BE FAIRLY WIDESPREAD. GIVEN
THAT THIS IS EXPECTED TO HAPPEN DURING THE MORNING TRAFFIC RUSH AN
AREAL FLOOD WATCH MAY BE WARRANTED. FOR NOW WE WILL DEFER THE
WATCH DECISION TO THE NEXT SHIFT FOR FURTHER EVALUATION OF MORE UP
TO DATE INFO. THERE IS A POSSIBLE SEVERE THREAT LATER TOMORROW
AFTERNOON/EVENING DEPENDING ON HOW MUCH SURFACE HEATING CAN BE
ACHIEVED. THIS WILL BE DEPENDENT ON CLOUD COVER. AS OF NOW OUR
WESTERN ZONES HAVE SOMEWHAT HIGHER CHANCES TO SEE SEVERE STORMS
THAN THE REST OF THE FA AS CLOUDS WILL BEGIN TO THIN FROM WEST TO
EAST.
WE SHOULD SEE PRECIP MOVE OFF THE THE EAST BY WED MORNING AS A FRONT
APPROACHES FROM THE NORTH. MODEL TIMING WITH THE FROPA DIFFERS WITH
THE GFS /FRONT PUSHING INTO OUR NORTHERN ZONES BY 00Z THURS/ BEING
SLOWER THAN THE ECMWF /FRONT THRU THE FA BY 00Z/. OTHER THAN WIND
SHIFT AND CLOUD COVER THIS SHOULDN/T CREATE MUCH OF A HEADACHE AS
FAR AS THE FORECAST IS CONCERNED. THE FROPA WILL BE ACCOMPANIED BY A
LOW STRATUS DECK THAT WILL STICK AROUND FOR MUCH OF WED NIGHT INTO
THURS AFTERNOON. RAIN WILL BE POSSIBLE MAINLY DUE TO ISENTROPIC
LIFTING. THE BIGGEST CHANGE TO THE FORECAST DURING THIS PERIOD IS
MAKING THE PRECIP MAINLY IN THE FORM OF RAIN WITH A MENTION OF ISO
THUNDER AS THE CHANCE EXISTS FOR SOME ELEVATED CAPE. ANOTHER LOW IS
PROGGED TO MOVE INLAND ACROSS SOCAL WHICH WILL RETURN SURFACE FLOW
TO OUT OF THE SOUTH/SOUTHEAST AND SET UP A DRYLINE OVER CENTRAL NM.
THIS WILL BE OUR NEXT BIG RAIN MAKER AS THE DRYLINE PUSHES EASTWARD
AND THEN RETREATS FRIDAY AND SATURDAY.
TEMPS WILL CONTINUE TO REMAIN BELOW SEASONAL AVERAGE AS CLOUD COVER
WILL BE ABUNDANT THRU THE WEEK AND SURFACE MOISTURE WILL HELP
MODERATE SURFACE TEMPS. THURS WILL BE PARTICULARLY CHILLY WITH TEMPS
AVERAGING 20 DEGREES BELOW SEASONAL AVERAGE /MID 60S/ DUE TO SURFACE
CAA ASSOCIATED WITH THE FROPA. ALDRICH
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 78 55 71 49 / 10 80 90 20
TULIA 79 57 69 51 / 10 80 90 40
PLAINVIEW 79 58 70 53 / 10 80 90 40
LEVELLAND 83 60 74 56 / 20 80 90 30
LUBBOCK 83 61 73 57 / 10 80 90 40
DENVER CITY 82 61 76 60 / 30 80 80 20
BROWNFIELD 84 61 74 59 / 20 80 90 30
CHILDRESS 86 63 71 60 / 10 60 90 60
SPUR 84 63 73 61 / 10 70 90 50
ASPERMONT 87 66 75 64 / 10 70 90 50
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
29/51
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1136 PM CDT SUN MAY 17 2015
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.UPDATE...
ISSUED AT 608 PM CDT SUN MAY 17 2015
STORMS HAVE DIMINISHED IN INTENSITY AND COVERAGE THE
LAST FEW HOURS OVER THE FORECAST AREA. MESO DATA SUGGESTS THE
REGION OF POTENTIAL NEW DEVELOPMENT OF STORMS LIKELY OVER THE
NORTHWEST HALF OF THE STATE...INCLUDING PARTS OF CENTRAL AND
NORTH CENTRAL WISCONSIN WITH THE BEST SHEAR VALUES...AND STEEP
SURFACE LAPSE RATES. ANTICIPATE THE SURFACE LAPSE RATES TO BE ON
THE DECLINE THE NEXT FEW HOURS...SO THE THREAT OF STRONG TO SEVERE
STORMS SHOULD LESSON. SPIRALING BANDS OF CONVECTION OVER EASTERN
MINNESOTA AND FAR WESTERN WISCONSIN CLOSER TO THE LOW PRESSURE
AREA OVER NORTHERN MINNESOTA MAY ROTATE INTO THIS ENVIRONMENT AND
INTENSIFY OVER NORTH CENTRAL WISCONSIN THIS EVENING.
&&
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 229 PM CDT SUN MAY 17 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW AN OCCLUDED
LOW PRESSURE SYSTEM SPINNING OVER THE EASTERN DAKOTAS. SHORTWAVES
ARE ROTATING NORTHWARD AHEAD OF THIS OCCLUDED CYCLONE...THE
STRONGEST OF WHICH IS LOCATED OVER EASTERN IOWA. A PWAT AXIS IS
MOVING ACROSS WISCONSIN EARLY THIS AFTERNOON...WHICH COMBINED WITH
MOISTURE CONVERGENCE...IS CONTRIBUTING TO SCATTERED SHOWER
DEVELOPMENT OVER CENTRAL WISCONSIN. CLOUD COVER HAS SIGNIFICANTLY
SLOWED THE HEATING CURVE SO FAR TODAY...KEEPING ML CAPES BELOW 200
J/KG. WITH SHOWER COVERAGE EXPECT TO INCREASE THROUGH THE
AFTERNOON...IT WILL BE TOUGH TO SEE MUCH OF AN INCREASE OF
INSTABILITY. STILL THOUGH...RADAR ECHOES SUGGEST SOME THUNDERSTORMS
WILL BE POSSIBLE...AND ANY STORMS COULD BRING DOWN STRONG WINDS FROM
ALOFT. WILL HAVE TO KEEP A MENTION OF ISOLATED DAMAGING WINDS
THROUGH EARLY THIS EVENING. OTHERWISE...THE LATEST HRRR CONGEALS THE
SHOWER ACTIVITY INTO BAND AND PROGRESSES IT ACROSS THE FORECAST AREA
FOR THE REST OF THE AFTERNOON.
TONIGHT...LOW PRESSURE WILL MOVE EAST ACROSS NORTHERN
MINNESOTA...WHILE A COLD FRONT WILL PUSH EAST THROUGH ALL BUT FAR
EASTERN WISCONSIN OVERNIGHT. THOUGH SHORTWAVE ENERGY WILL BE
ROTATING NORTHEAST OVER NORTHWEST WISCONSIN THROUGH THE
EVENING...CONCERNED THAT STRONG DRYING AND INCREASING CAPPING IN THE
MID-LEVELS WILL EVEN FURTHER LIMIT THUNDERSTORM POTENTIAL FOR THE
FIRST COUPLE HOURS IN THE EVENING. WILL KEEP A MENTION OF ISOLATED
DAMAGING WINDS THROUGH 02Z IN CASE SOME THUNDERSTORMS MAKE A RUN
INTO N-C WISCONSIN FROM MINNESOTA. ONCE THE THREAT OF STORMS ENDS...MODELS
SHOW CLEARING TAKING PLACE UNTIL LOW CLOUDS FLOOD EAST BEHIND THE
COLD FRONT LATE TONIGHT. LOW TEMPS NEAR 60 OVER THE EAST...BUT
COOLING TO NEAR 50 OVER THE WEST.
MONDAY...OCCLUDED LOW PRESSURE WILL BE WEAKENING AS IT MOVES TO THE
EAST ACROSS LAKE SUPERIOR. WEST WINDS ON THE SOUTHERN FLANK OF THE
LOW WILL BE COLD ADVECTING THROUGH THE DAY...WHILE PUSHING IN WRAP
AROUND MOISTURE. SHOULD SEE AMPLE CLOUD COVER OVER CENTRAL AND
NORTH-CENTRAL WISCONSIN THROUGH THE DAY...BUT EAST-CENTRAL WISCONSIN
WILL LIKELY SEE SOME SUN IN THE MORNING BEFORE CLOUDS INCREASE IN
THE AFTERNOON. WITH THE SUNSHINE...TEMPS SHOULD WARM TO NEAR 70 IN
THE EAST...BUT ONLY INTO THE MID AND UPPER 50S OVER THE WEST.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 229 PM CDT SUN MAY 17 2015
MUCH COOLER TEMPERATURES FOR THE FIRST HALF OF THE WORK WEEK...DRY
AND MILDER CONDITIONS FOR THE LATTER HALF...AND A POSSIBLE RETURN
TO WET WEATHER LATER IN THE MEMORIAL DAY WEEKEND...ARE THE MAIN
FCST CONCERNS.
THE REMNANTS OF THE UPPER LOW WILL TRACK ACROSS NORTHERN LAKE SUPERIOR
ON MONDAY NIGHT...FOLLOWED BY A S/W TROF PASSING NORTH OF WI ON TUESDAY.
UNSEASONABLY COLD AIR (H8 TEMPS -8 TO -10 C) WILL FLOW INTO THE REGION
ON NNW WINDS...SETTING THE STAGE FOR SOME LAKE-ENHANCED SHOWERS OVER
NC WI. LOW-LEVEL TEMPS AND THICKNESSES SUPPORT A MIX THEN CHANGEOVER
TO SNOW LATE MONDAY NIGHT INTO TUESDAY MORNING...WITH LITTLE OR NO
ACCUMULATION EXPECTED. ANY LINGERING PCPN SHOULD END TUESDAY AFTERNOON
AS CANADIAN HIGH PRESSURE BUILDS INTO THE REGION.
HIGH PRESSURE WILL COVER THE AREA TUESDAY NIGHT INTO WEDNESDAY. STILL
EXPECTING FROST TUESDAY NIGHT...BUT GETTING A LITTLE CONCERNED ABOUT
THE POSSIBILITY OF THICKER HIGH LEVEL CLOUDS...DUE TO THE PRESENCE
OF A STRONG JET STREAK OVER THE REGION. RIGHT NOW...HAVE JUST
BUMPED UP CLOUD COVER A BIT OVER C/EC WI...BUT KEPT MOSTLY CLEAR
SKIES OVER NORTHERN WI. WILL CONTINUE TO CARRY WIDESPREAD FROST OR
FREEZE CONDITIONS OVER NORTHERN WI...AND PATCHY FROST OVER MOST OF
C/EC WI.
A WEAK BACK DOOR COLD FRONT WILL SAG THROUGH THE FORECAST AREA THURSDAY
INTO THURSDAY NIGHT...BUT WILL NOT HAVE ANY MOISTURE TO WORK WITH...SO
DRY WEATHER WILL PREVAIL. BEHIND THE FRONT...CANADIAN HIGH PRESSURE
WILL REESTABLISH ITSELF OVER THE WESTERN GREAT LAKES...AND IS EXPECTED
TO LINGER INTO SATURDAY. ABUNDANT SUNSHINE SHOULD BRING A RETURN TO
NEAR NORMAL TEMPERATURES FOR THE LATTER HALF OF THE WEEK.
AN UPPER TROF...LOW PRESSURE SYSTEM AND ASSOCIATED COLD FRONT WILL
IMPACT THE REGION FROM SATURDAY NIGHT INTO SUNDAY. GULF MOISTURE
IS EXPECTED TO FLOW INTO THE REGION AHEAD OF THE FRONT...WITH
PRECIPITABLE WATER VALUES REACHING 1.00-1.25 INCHES. HAVE RAMPED
POPS UP TO LIKELY FOR SUNDAY. THE ECMWF PULLS MOST OF THE PCPN OUT
OF THE REGION SUNDAY EVG...WHILE THE GFS HANGS ONTO SIGNIFICANT
QPF INTO MEMORIAL DAY...SO FCST CONFIDENCE WANES BEYOND SUNDAY.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1135 PM CDT SUN MAY 17 2015
LAST OF THE SHOWERS WERE DEPARTING FAR NORTH CENTRAL
WISCONSIN LATE THIS EVENING. OTHERWISE VFR CONDITIONS TO PREVAIL
OVERNIGHT ALONG WITH LLWS CONDITIONS. LLWS CONDITIONS WILL END
MONDAY MORNING BUT BLUSTERY WEST SURFACE WINDS WILL DEVELOP.
WRAP AROUND MVFR CIGS DUE TO THE DEPARTING UPPER LOW SYSTEM WILL
BEGIN TO WORK INTO CENTRAL AND NORTH CENTRAL WISCONSIN MONDAY
MORNING. CIGS WILL CONTINUE TO WORK INTO EASTERN AREAS BUT WILL
MORE OF THE LOWER END VFR CIGS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE.........TDH
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1029 AM EDT MON MAY 18 2015
.SYNOPSIS...
ISSUED AT 1024 AM EDT MON MAY 18 2015
A COLD FRONT WILL APPROACH THE REGION THIS AFTERNOON. SCATTERED
SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG AND JUST IN ADVANCE OF
THE FRONT THIS AFTERNOON INTO EARLY THIS EVENING BEFORE
DIMINISHING. THE PASSAGE OF THIS COLD FRONT WILL RESULT IN MUCH
COOLER CONDITIONS THROUGH THE MIDDLE PORTIONS OF THE WEEK. HIGH
TEMPERATURES THIS AFTERNOON WILL BE MAINLY IN THE LOWER 80S.
LOW TEMPERATURES TONIGHT WILL DROP BACK INTO UPPER 40S TO LOWER
50S. HIGHS TUESDAY AND WEDNESDAY WILL RANGE FROM THE MID 50S TO
LOWER 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EDT MON MAY 18 2015
DRIER MID LEVEL AIR HAS ADVECTED INTO MOST OF THE FORECAST AREA THIS
MORNING. DEEPEST MOISTURE THROUGH THE MORNING HOURS IS EXPECTED TO
RESIDE ACROSS APPROXIMATELY THE SOUTHEAST THIRD OF THE AREA WHERE
SOME UPSWING IN 850-700 HPA MOISTURE TRANSPORT IS EXPECTED OVER THE
NEXT SEVERAL HOURS. 3-6 HOUR RAP PROGS DO INDICATE ABOUT 250-500
J/KG OF INSTABILITY LINGERING ACROSS THESE LOCATIONS EXPERIENCING
STRONGER MOISTURE TRANSPORT THIS MORNING...SO HAVE CONTINUED TO
CONCENTRATE LOW CHANCE POPS ACROSS THE SOUTHEAST THIS MORNING AS
ADDITIONAL WEAK SHORT WAVES TRACK NORTHEAST THROUGH THE OHIO VALLEY
IN ASSOCIATION WITH SOUTHERN STREAM.
ATTENTION FOR THE REMAINDER OF THE DAY WILL CENTER ON EVOLUTION OF
SFC COLD FRONTAL BOUNDARY AND POTENTIAL OF ANY ADDITIONAL SCATTERED
CONVECTION THIS AFTERNOON/EARLY EVENING. INSPECTION OF SHORT TERM
TRENDS SUGGESTS NAM MAY BE JUST A BIT SLOW WITH COLD FRONT ACROSS
THE MID MS RVR VALLEY...AND THE NAM CONTINUES TO BE SOMEWHAT OF A
SLOW OUTLIER THROUGH THE NEXT 24 HOURS WITH THE FRONTAL PROGRESSION.
EVEN WITH A PROGRESSION SOMEWHAT FASTER THAN THE NAM...PREFRONTAL
WARMING SHOULD SUPPORT HIGHS IN THE LOWER 80S FOR MOST LOCATIONS
THIS AFTERNOON. OUTSIDE OF FRONTAL CONVERGENCE...MID/UPPER LEVEL
FORCING IS EXPECTED TO BE QUITE WEAK...ALTHOUGH WATER VAPOR EARLY
THIS MORNING DOES DEPICT SOME INTEGRITY TO AN UPSTREAM WAVE LIFTING
NORTHEAST OUT OF OKLAHOMA/SOUTHEAST MISSOURI. THIS FEATURE SHOULD
RAPIDLY EJECT NORTHEAST...BUT BECOME LESS POTENT AS IT BECOMES MORE
HIGHLY SHEARED ACROSS THE OHIO VALLEY/SOUTHERN GREAT LAKES REGION
LATER THIS AFTERNOON/THIS EVENING.
SOME OF THE NAM AND HIRES OUTPUT DOES INDICATE A NARROW ZONE OF
PREFRONTAL CONFLUENCE WITH SOME SUBSTANTIAL MOISTURE POOLING. HAVE
SOME SUSPICION THE SLOWER NAM OUTLIER MAY BE A BIT AGGRESSIVE IN
TERMS OF THE MAGNITUDE OF THIS MOISTURE POOLING AND HAVE GENERALLY
TRENDED AWAY FROM THE INSTABILITY MAGNITUDES ADVERTISED BY THE NAM
ALONG THIS PREFRONTAL CORRIDOR. HAVE MAINTAINED LOW TO MID CHANCE
TSRA FOR TODAY GIVEN AT LEAST SOME WEAK MID/UPPER FORCING LIFTING
INTO THE AREA WITH AFOREMENTIONED OK/MO VORT...ALTHOUGH OUTSIDE OF
ANY AREAS OF PREFRONTAL MOISTURE POOLING...LOW LEVELS MAY MIX OUT
ENOUGH TO TEMPER INSTABILITY QUITE A BIT BY LATER THIS AFTERNOON. IF
SCATTERED CONVECTION IS ABLE TO DEVELOP THERE MAY BE TWO PRIMARY
CORRIDORS FOR INITIATION...ONE ALONG ANY WEAK PREFRONTAL CONVERGENCE
ZONE...AND THEN ALONG THE ACTUAL FRONTAL BOUNDARY. SEVERE STORMS ARE
NOT EXPECTED IN TRENDING TOWARD NON-NAM GUIDANCE FOR THERMAL
PROFILES...AND ALSO GIVEN MORE OF THE SUBSTANTIAL DEEP LAYER SHEAR
WILL BE POST-FRONTAL.
SOME ISOLATED CONVECTION MAY LINGER INTO THE EVENING ACROSS
SOUTHEAST HALF OF THE AREA...WITH MAIN STORY THROUGH THE REMAINDER
OF THE NIGHT CENTERING ON THE APPROACH OF A MUCH COOLER AND LESS
HUMID AIR MASS. SOME COLD ADVECTION STRATOCU MAY WORK INTO FAR
NORTHERN LOCATIONS OVERNIGHT...BUT OTHERWISE MOST LOCATIONS WILL
EXPERIENCE CLEARING SKIES IN THE EVENING.
&&
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 358 AM EDT MON MAY 18 2015
TRANQUIL WEATHER ANTICIPATED FOR MUCH OF THIS LONG TERM PERIOD.
SPLIT FLOW OVER WESTERN NOAM WITH A HIGHLY AMPLIFIED AND ENDURING
NORTHERN STREAM PATTERN ACROSS CANADA WILL LEAVE THE GREAT LAKES IN
A REGION OF STRONG CONFLUENCE AND GENERAL SUBSIDENCE FOR MOST OF
THIS WEEK. WILL ALSO BE MUCH COOLER BEHIND TODAY`S COLD FRONT WITH
PERSISTENT N/NW FLOW MAINTAINING AN EFFICIENT FEED OF CANADIAN AIR
INTO OUR REGION. EXPECT TEMPS ROUGHLY 10-15 DEGREES BELOW NORMAL
DURING THE MIDWEEK PERIOD. TUESDAY NIGHT WILL BE THE COLDEST PERIOD
WITH NUMEROUS SOURCES OF RAW AND STATISTICAL GUIDANCE SUGGESTING MID
30S IN OUR NORTHERN COUNTIES...WITH LOWER 40S IN OUR SOUTH. SOME
CONCERN FOR PATCHY FROST...ESPECIALLY IN OUR MICHIGAN COUNTIES AWAY
FROM THE LAKE. HOWEVER...HIGH BASED CLOUDS WILL BE INCREASING BY
WEDNESDAY MORNING AND MODELS SHOW ENOUGH OF A SURFACE PRESSURE
GRADIENT TO KEEP WINDS IN THE 5-10 MPH RANGE. GIVEN THESE CONCERNS
AND MARGINAL TEMPS WILL HOLD OFF ON MENTIONING ANY FROST IN THE
FORECAST AT THIS POINT AND CONTINUE TO MONITOR.
ONE WEAK SOUTHERN STREAM WAVE DOES EJECT OUT OF THE FOUR CORNERS AND
ATTEMPT TO PHASE WITH SUBTLE NORTHERN STREAM VORT MAX AS IT CROSSES
OUR AREA LATE WEDNESDAY. DEGREE OF DRY AND STABLE LOWER LEVELS IS
CONCERNING BUT FAVORABLE 300MB JET PLACEMENT AND SOME MODEST
CVA/HEIGHT FALLS COULD GENERATE A FEW LIGHT RAIN SHOWERS. NO MAJOR
QUALMS WITH INHERITED LOW CHANCE POPS BUT DID ADJUST THE TIMING UP A
LITTLE BIT BASED ON LATEST NAM AND ECMWF SOLUTIONS. NEXT CHANCE OF
RAIN THEREAFTER WILL NOT BE UNTIL SUNDAY WHEN SOUTHWEST FLOW FINALLY
RETURNS AHEAD OF NEXT WESTERN CONUS TROUGH EJECTING NORTHEAST. THIS
PATTERN SHIFT WILL ALSO SIGNAL THE RETURN OF WARMER AND MORE HUMID
CONDITIONS FOR AT LEAST THE LATTER HALF OF THE HOLIDAY WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 637 AM EDT MON MAY 18 2015
MVFR CIGS TO LINGER THIS MORNING AT KFWA...BUT SHOULD TREND TO VFR
BY THE 14Z OR 15Z TIMEFRAME WITH DIURNAL WARMING. MAIN FEATURE OF
INTEREST FOR TODAY WILL BE APPROACHING COLD FRONTAL BOUNDARY THAT
MAY TRIGGER SOME ISOLATED OR SCATTERED AFTERNOON SHOWERS AND
THUNDERSTORMS. LOW LEVEL MIXING IN THE AFTERNOON MAY TEND TO
DISCOURAGE LARGE MAGNITUDES TO AFTERNOON INSTABILITY HOWEVER...SO
CONFIDENCE REMAINS LOW ON THUNDER PROBABILITIES AT KFWA.
INSTABILITY EVEN LESS SUBSTANTIAL AT KSBN...SO WILL CONTINUE TO
OMIT ANY PRECIP MENTION. LIGHT SOUTH SOUTHWEST WINDS THIS MORNING
WILL BECOME GUSTY INTO THE 15 TO 22 KNOT RANGE THIS AFTERNOON
AHEAD OF THE FRONT...WITH A WIND SHIFT TO THE WEST OR WEST
NORTHWEST FOR LATE AFTERNOON/EARLY EVENING BEHIND THE COLD FRONT.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 5 PM EDT TUESDAY
FOR LMZ043-046.
&&
$$
SYNOPSIS...SKIPPER
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...MARSILI/SKIPPER
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSIWX
WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
646 AM EDT MON MAY 18 2015
.SYNOPSIS...
ISSUED AT 358 AM EDT MON MAY 18 2015
A COLD FRONT WILL APPROACH THE REGION THIS AFTERNOON. SCATTERED
SHOWERS AND THUNDERSTORMS MAY DEVELOP ALONG AND JUST IN ADVANCE OF
THE FRONT THIS AFTERNOON INTO EARLY THIS EVENING BEFORE
DIMINISHING. THE PASSAGE OF THIS COLD FRONT WILL RESULT IN MUCH
COOLER CONDITIONS THROUGH THE MIDDLE PORTIONS OF THE WEEK. HIGH
TEMPERATURES THIS AFTERNOON WILL RANGE FROM THE UPPER 70S TO LOWER
80S. LOW TEMPERATURES TONIGHT WILL DROP BACK INTO UPPER 40S TO
LOWER 50S. HIGH TEMPERATURES ON TUESDAY AND WEDNESDAY WILL RANGE
FROM THE MID 50S TO LOWER 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EDT MON MAY 18 2015
DRIER MID LEVEL AIR HAS ADVECTED INTO MOST OF THE FORECAST AREA THIS
MORNING. DEEPEST MOISTURE THROUGH THE MORNING HOURS IS EXPECTED TO
RESIDE ACROSS APPROXIMATELY THE SOUTHEAST THIRD OF THE AREA WHERE
SOME UPSWING IN 850-700 HPA MOISTURE TRANSPORT IS EXPECTED OVER THE
NEXT SEVERAL HOURS. 3-6 HOUR RAP PROGS DO INDICATE ABOUT 250-500
J/KG OF INSTABILITY LINGERING ACROSS THESE LOCATIONS EXPERIENCING
STRONGER MOISTURE TRANSPORT THIS MORNING...SO HAVE CONTINUED TO
CONCENTRATE LOW CHANCE POPS ACROSS THE SOUTHEAST THIS MORNING AS
ADDITIONAL WEAK SHORT WAVES TRACK NORTHEAST THROUGH THE OHIO VALLEY
IN ASSOCIATION WITH SOUTHERN STREAM.
ATTENTION FOR THE REMAINDER OF THE DAY WILL CENTER ON EVOLUTION OF
SFC COLD FRONTAL BOUNDARY AND POTENTIAL OF ANY ADDITIONAL SCATTERED
CONVECTION THIS AFTERNOON/EARLY EVENING. INSPECTION OF SHORT TERM
TRENDS SUGGESTS NAM MAY BE JUST A BIT SLOW WITH COLD FRONT ACROSS
THE MID MS RVR VALLEY...AND THE NAM CONTINUES TO BE SOMEWHAT OF A
SLOW OUTLIER THROUGH THE NEXT 24 HOURS WITH THE FRONTAL PROGRESSION.
EVEN WITH A PROGRESSION SOMEWHAT FASTER THAN THE NAM...PREFRONTAL
WARMING SHOULD SUPPORT HIGHS IN THE LOWER 80S FOR MOST LOCATIONS
THIS AFTERNOON. OUTSIDE OF FRONTAL CONVERGENCE...MID/UPPER LEVEL
FORCING IS EXPECTED TO BE QUITE WEAK...ALTHOUGH WATER VAPOR EARLY
THIS MORNING DOES DEPICT SOME INTEGRITY TO AN UPSTREAM WAVE LIFTING
NORTHEAST OUT OF OKLAHOMA/SOUTHEAST MISSOURI. THIS FEATURE SHOULD
RAPIDLY EJECT NORTHEAST...BUT BECOME LESS POTENT AS IT BECOMES MORE
HIGHLY SHEARED ACROSS THE OHIO VALLEY/SOUTHERN GREAT LAKES REGION
LATER THIS AFTERNOON/THIS EVENING.
SOME OF THE NAM AND HIRES OUTPUT DOES INDICATE A NARROW ZONE OF
PREFRONTAL CONFLUENCE WITH SOME SUBSTANTIAL MOISTURE POOLING. HAVE
SOME SUSPICION THE SLOWER NAM OUTLIER MAY BE A BIT AGGRESSIVE IN
TERMS OF THE MAGNITUDE OF THIS MOISTURE POOLING AND HAVE GENERALLY
TRENDED AWAY FROM THE INSTABILITY MAGNITUDES ADVERTISED BY THE NAM
ALONG THIS PREFRONTAL CORRIDOR. HAVE MAINTAINED LOW TO MID CHANCE
TSRA FOR TODAY GIVEN AT LEAST SOME WEAK MID/UPPER FORCING LIFTING
INTO THE AREA WITH AFOREMENTIONED OK/MO VORT...ALTHOUGH OUTSIDE OF
ANY AREAS OF PREFRONTAL MOISTURE POOLING...LOW LEVELS MAY MIX OUT
ENOUGH TO TEMPER INSTABILITY QUITE A BIT BY LATER THIS AFTERNOON. IF
SCATTERED CONVECTION IS ABLE TO DEVELOP THERE MAY BE TWO PRIMARY
CORRIDORS FOR INITIATION...ONE ALONG ANY WEAK PREFRONTAL CONVERGENCE
ZONE...AND THEN ALONG THE ACTUAL FRONTAL BOUNDARY. SEVERE STORMS ARE
NOT EXPECTED IN TRENDING TOWARD NON-NAM GUIDANCE FOR THERMAL
PROFILES...AND ALSO GIVEN MORE OF THE SUBSTANTIAL DEEP LAYER SHEAR
WILL BE POST-FRONTAL.
SOME ISOLATED CONVECTION MAY LINGER INTO THE EVENING ACROSS
SOUTHEAST HALF OF THE AREA...WITH MAIN STORY THROUGH THE REMAINDER
OF THE NIGHT CENTERING ON THE APPROACH OF A MUCH COOLER AND LESS
HUMID AIR MASS. SOME COLD ADVECTION STRATOCU MAY WORK INTO FAR
NORTHERN LOCATIONS OVERNIGHT...BUT OTHERWISE MOST LOCATIONS WILL
EXPERIENCE CLEARING SKIES IN THE EVENING.
&&
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 358 AM EDT MON MAY 18 2015
TRANQUIL WEATHER ANTICIPATED FOR MUCH OF THIS LONG TERM PERIOD.
SPLIT FLOW OVER WESTERN NOAM WITH A HIGHLY AMPLIFIED AND ENDURING
NORTHERN STREAM PATTERN ACROSS CANADA WILL LEAVE THE GREAT LAKES IN
A REGION OF STRONG CONFLUENCE AND GENERAL SUBSIDENCE FOR MOST OF
THIS WEEK. WILL ALSO BE MUCH COOLER BEHIND TODAY`S COLD FRONT WITH
PERSISTENT N/NW FLOW MAINTAINING AN EFFICIENT FEED OF CANADIAN AIR
INTO OUR REGION. EXPECT TEMPS ROUGHLY 10-15 DEGREES BELOW NORMAL
DURING THE MIDWEEK PERIOD. TUESDAY NIGHT WILL BE THE COLDEST PERIOD
WITH NUMEROUS SOURCES OF RAW AND STATISTICAL GUIDANCE SUGGESTING MID
30S IN OUR NORTHERN COUNTIES...WITH LOWER 40S IN OUR SOUTH. SOME
CONCERN FOR PATCHY FROST...ESPECIALLY IN OUR MICHIGAN COUNTIES AWAY
FROM THE LAKE. HOWEVER...HIGH BASED CLOUDS WILL BE INCREASING BY
WEDNESDAY MORNING AND MODELS SHOW ENOUGH OF A SURFACE PRESSURE
GRADIENT TO KEEP WINDS IN THE 5-10 MPH RANGE. GIVEN THESE CONCERNS
AND MARGINAL TEMPS WILL HOLD OFF ON MENTIONING ANY FROST IN THE
FORECAST AT THIS POINT AND CONTINUE TO MONITOR.
ONE WEAK SOUTHERN STREAM WAVE DOES EJECT OUT OF THE FOUR CORNERS AND
ATTEMPT TO PHASE WITH SUBTLE NORTHERN STREAM VORT MAX AS IT CROSSES
OUR AREA LATE WEDNESDAY. DEGREE OF DRY AND STABLE LOWER LEVELS IS
CONCERNING BUT FAVORABLE 300MB JET PLACEMENT AND SOME MODEST
CVA/HEIGHT FALLS COULD GENERATE A FEW LIGHT RAIN SHOWERS. NO MAJOR
QUALMS WITH INHERITED LOW CHANCE POPS BUT DID ADJUST THE TIMING UP A
LITTLE BIT BASED ON LATEST NAM AND ECMWF SOLUTIONS. NEXT CHANCE OF
RAIN THEREAFTER WILL NOT BE UNTIL SUNDAY WHEN SOUTHWEST FLOW FINALLY
RETURNS AHEAD OF NEXT WESTERN CONUS TROUGH EJECTING NORTHEAST. THIS
PATTERN SHIFT WILL ALSO SIGNAL THE RETURN OF WARMER AND MORE HUMID
CONDITIONS FOR AT LEAST THE LATTER HALF OF THE HOLIDAY WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 637 AM EDT MON MAY 18 2015
MVFR CIGS TO LINGER THIS MORNING AT KFWA...BUT SHOULD TREND TO VFR
BY THE 14Z OR 15Z TIMEFRAME WITH DIURNAL WARMING. MAIN FEATURE OF
INTEREST FOR TODAY WILL BE APPROACHING COLD FRONTAL BOUNDARY THAT
MAY TRIGGER SOME ISOLATED OR SCATTERED AFTERNOON SHOWERS AND
THUNDERSTORMS. LOW LEVEL MIXING IN THE AFTERNOON MAY TEND TO
DISCOURAGE LARGE MAGNITUDES TO AFTERNOON INSTABILITY HOWEVER...SO
CONFIDENCE REMAINS LOW ON THUNDER PROBABILITIES AT KFWA.
INSTABILITY EVEN LESS SUBSTANTIAL AT KSBN...SO WILL CONTINUE TO
OMIT ANY PRECIP MENTION. LIGHT SOUTH SOUTHWEST WINDS THIS MORNING
WILL BECOME GUSTY INTO THE 15 TO 22 KNOT RANGE THIS AFTERNOON
AHEAD OF THE FRONT...WITH A WIND SHIFT TO THE WEST OR WEST
NORTHWEST FOR LATE AFTERNOON/EARLY EVENING BEHIND THE COLD FRONT.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 5 PM EDT TUESDAY
FOR LMZ043-046.
&&
$$
SYNOPSIS...MARSILI
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...MARSILI
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
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AREA FORECAST DISCUSSION
NWS JACKSON KY
938 AM EDT MON MAY 18 2015
.UPDATE...
ISSUED AT 938 AM EDT MON MAY 18 2015
JUST MADE SOME ADJUSTMENTS TO THE FORECAST GRIDS THROUGH THE REST
OF THE MORNING. BASED ON CURRENT RADAR IMAGERY...POPS IN OUR
SOUTHWESTERN AND WESTERN COUNTIES NEEDED TO BE INCREASED. WENT
THROUGH AND INCREASED HOURLY POPS OVER THE NEXT 4 HOURS BY 10 TO
15 PERCENT TO ACCOUNT FOR REAL TIME TRENDS. THIS DID NOT CHANGE
THE WORDING IN THE ZONE FORECAST TEXT PRODUCT SO NO UPDATE TO THAT
WAS NECESSARY. IN SUMMARY...THE POP...POP12...AND WEATHER TYPE
GRIDS HAVE ALL BEEN UPDATED.
UPDATE ISSUED AT 709 AM EDT MON MAY 18 2015
A FEW ISOLATED SHOWERS MAINLY ACROSS THE EAST SHOWING UP THIS
MORNING ON WSR-88D RADAR...WITH MORE SHOWERS SLOWLY MOVING EAST
INTO WESTERN PORTIONS OF THE REGION AS WE GO THROUGH THE MORNING.
STORM COVERAGE WILL CONTINUE TO INCREASE THIS AFTERNOON AHEAD OF A
COLD FRONT ACROSS THE UPPER MIDWEST. UPDATED GRIDS WITH LATEST
OBS AND TRENDS. OTHERWISE NO MAJOR CHANGES NEEDED THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON MAY 18 2015
03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER
MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE
CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL
THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT
UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS
CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE
THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY
MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN
KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS
ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED
ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST
FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY.
THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND
17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT
LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN
PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE
ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA
SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE
MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE
THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED
CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE
THIS AFTERNOON.
ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES
OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND
CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID
KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK
THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER
AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY
SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 434 AM EDT MON MAY 18 2015
SURFACE HIGH PRESSURE RIDGING SE FROM THE NORTH CENTRAL CONUS
WILL PROVIDE DRY WEATHER AT THE START OF THE PERIOD. A PIECE OF AN
UPPER LOW CURRENTLY OVER CA WILL MAKE ITS WAY EASTWARD ACROSS THE
CONUS AT MIDWEEK...AND AS ANOTHER UPPER LOW DROPS SE TOWARD NEW
ENGLAND...THE TWO WILL COMBINE TO BRING AN AMPLIFYING TROUGH TO
THE EASTERN CONUS. AS THE WEAK UPPER LEVEL SYSTEM MOVES IN FROM
THE WEST...THE ECMWF IS MORE ACTIVE WITH THE SYSTEM...AND IT SHOWS
A WEAKENING SURFACE LOW ASSOCIATED WITH IT. THIS BRINGS LIGHT
PRECIP TO OUR LOCAL AREA IN THE WEDNESDAY NIGHT/THURSDAY TIME
FRAME. THE GFS IS WEAKER WITH THE SYSTEM AND ONLY BRINGS CLOUDS.
HAVE OPTED TO USE A MINIMAL 20 PERCENT POP AT THIS POINT.
ONCE THIS SYSTEM MOVES TO OUR EAST BY THURSDAY NIGHT...MODELS AGREE
ON A SURFACE HIGH PRESSURE SYSTEM BUILDING IN FROM THE NW WITH A
REINFORCING PUSH OF DRY AIR. THIS SHOULD HOLD INTO THE WEEKEND.
LATE IN THE WEEKEND MOISTURE SHOULD BE ON THE INCREASE AGAIN AS
THE HIGH MOVES OFF THE EAST COAST AND LOW PRESSURE DEVELOPS OVER
THE PLAINS...TURNING OUR LOW LEVEL FLOW TO THE SOUTH. HAVE
INCLUDED LOW POPS ON SUNDAY...BUT THE BETTER CHANCE OF PRECIP WILL
BE TO OUR WEST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 657 AM EDT MON MAY 18 2015
FOG DEVELOPMENT WAS WEAKENED BY THE CLOUDS THAT CONTINUED TO BUILD
ACROSS THE REGION OVERNIGHT INTO THIS MORNING. PATCHY FOG WILL BE
POSSIBLE ACROSS RIVER VALLEYS AND THOSE AREAS THAT RECEIVED RAIN.
A FEW ISOLATED SHOWERS CONTINUE TO POP UP ACROSS PORTIONS OF THE
REGION THIS MORNING AND HAVE INCLUDED VCSH AT A FEW SITES TO
START...BUT ADD TO ALL SITES AS WE MOVE THROUGH THE MORNING.
OTHERWISE BIGGEST ISSUE TODAY WILL BE SHOWERS AND THUNDERSTORMS
DEVELOPING ACROSS EASTERN KENTUCKY THIS AFTERNOON. THE BEST
COVERAGE WILL BE IN THE AFTERNOON WITH DAYTIME HEATING. THEREFORE
DID OPT TO ADD A TEMPO GROUP WITH MVFR VIS TO THE TAF SITES
GENERALLY BETWEEN 18Z AND 19Z. OTHERWISE THINK SITES WILL
GENERALLY KEEP VFR CONDITIONS FOR MUCH OF THE TAF PERIOD. KEPT
WINDS LIGHT TIL THIS AFTERNOON WITH SITES POSSIBLY SEEING GUSTS UP
TO 15 KTS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...DJ
LONG TERM...HAL
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
709 AM EDT MON MAY 18 2015
.UPDATE...
ISSUED AT 709 AM EDT MON MAY 18 2015
A FEW ISOLATED SHOWERS MAINLY ACROSS THE EAST SHOWING UP THIS
MORNING ON WSR-88D RADAR...WITH MORE SHOWERS SLOWLY MOVING EAST
INTO WESTERN PORTIONS OF THE REGION AS WE GO THROUGH THE MORNING.
STORM COVERAGE WILL CONTINUE TO INCREASE THIS AFTERNOON AHEAD OF A
COLD FRONT ACROSS THE UPPER MIDWEST. UPDATED GRIDS WITH LATEST
OBS AND TRENDS. OTHERWISE NO MAJOR CHANGES NEEDED THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON MAY 18 2015
03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER
MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE
CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL
THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT
UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS
CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE
THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY
MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN
KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS
ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED
ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST
FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY.
THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND
17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT
LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN
PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE
ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA
SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE
MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE
THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED
CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE
THIS AFTERNOON.
ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES
OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND
CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID
KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK
THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER
AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY
SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 434 AM EDT MON MAY 18 2015
SURFACE HIGH PRESSURE RIDGING SE FROM THE NORTH CENTRAL CONUS
WILL PROVIDE DRY WEATHER AT THE START OF THE PERIOD. A PIECE OF AN
UPPER LOW CURRENTLY OVER CA WILL MAKE ITS WAY EASTWARD ACROSS THE
CONUS AT MIDWEEK...AND AS ANOTHER UPPER LOW DROPS SE TOWARD NEW
ENGLAND...THE TWO WILL COMBINE TO BRING AN AMPLIFYING TROUGH TO
THE EASTERN CONUS. AS THE WEAK UPPER LEVEL SYSTEM MOVES IN FROM
THE WEST...THE ECMWF IS MORE ACTIVE WITH THE SYSTEM...AND IT SHOWS
A WEAKENING SURFACE LOW ASSOCIATED WITH IT. THIS BRINGS LIGHT
PRECIP TO OUR LOCAL AREA IN THE WEDNESDAY NIGHT/THURSDAY TIME
FRAME. THE GFS IS WEAKER WITH THE SYSTEM AND ONLY BRINGS CLOUDS.
HAVE OPTED TO USE A MINIMAL 20 PERCENT POP AT THIS POINT.
ONCE THIS SYSTEM MOVES TO OUR EAST BY THURSDAY NIGHT...MODELS AGREE
ON A SURFACE HIGH PRESSURE SYSTEM BUILDING IN FROM THE NW WITH A
REINFORCING PUSH OF DRY AIR. THIS SHOULD HOLD INTO THE WEEKEND.
LATE IN THE WEEKEND MOISTURE SHOULD BE ON THE INCREASE AGAIN AS
THE HIGH MOVES OFF THE EAST COAST AND LOW PRESSURE DEVELOPS OVER
THE PLAINS...TURNING OUR LOW LEVEL FLOW TO THE SOUTH. HAVE
INCLUDED LOW POPS ON SUNDAY...BUT THE BETTER CHANCE OF PRECIP WILL
BE TO OUR WEST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 657 AM EDT MON MAY 18 2015
FOG DEVELOPMENT WAS WEAKENED BY THE CLOUDS THAT CONTINUED TO BUILD
ACROSS THE REGION OVERNIGHT INTO THIS MORNING. PATCHY FOG WILL BE
POSSIBLE ACROSS RIVER VALLEYS AND THOSE AREAS THAT RECEIVED RAIN.
A FEW ISOLATED SHOWERS CONTINUE TO POP UP ACROSS PORTIONS OF THE
REGION THIS MORNING AND HAVE INCLUDED VCSH AT A FEW SITES TO
START...BUT ADD TO ALL SITES AS WE MOVE THROUGH THE MORNING.
OTHERWISE BIGGEST ISSUE TODAY WILL BE SHOWERS AND THUNDERSTORMS
DEVELOPING ACROSS EASTERN KENTUCKY THIS AFTERNOON. THE BEST
COVERAGE WILL BE IN THE AFTERNOON WITH DAYTIME HEATING. THEREFORE
DID OPT TO ADD A TEMPO GROUP WITH MVFR VIS TO THE TAF SITES
GENERALLY BETWEEN 18Z AND 19Z. OTHERWISE THINK SITES WILL
GENERALLY KEEP VFR CONDITIONS FOR MUCH OF THE TAF PERIOD. KEPT
WINDS LIGHT TIL THIS AFTERNOON WITH SITES POSSIBLY SEEING GUSTS UP
TO 15 KTS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DJ
SHORT TERM...DJ
LONG TERM...HAL
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS JACKSON KY
657 AM EDT MON MAY 18 2015
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON MAY 18 2015
03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER
MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE
CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL
THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT
UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS
CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE
THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY
MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN
KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS
ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED
ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST
FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY.
THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND
17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT
LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN
PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE
ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA
SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE
MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE
THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED
CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE
THIS AFTERNOON.
ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES
OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND
CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID
KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK
THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER
AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY
SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 434 AM EDT MON MAY 18 2015
SURFACE HIGH PRESSURE RIDGING SE FROM THE NORTH CENTRAL CONUS
WILL PROVIDE DRY WEATHER AT THE START OF THE PERIOD. A PIECE OF AN
UPPER LOW CURRENTLY OVER CA WILL MAKE ITS WAY EASTWARD ACROSS THE
CONUS AT MIDWEEK...AND AS ANOTHER UPPER LOW DROPS SE TOWARD NEW
ENGLAND...THE TWO WILL COMBINE TO BRING AN AMPLIFYING TROUGH TO
THE EASTERN CONUS. AS THE WEAK UPPER LEVEL SYSTEM MOVES IN FROM
THE WEST...THE ECMWF IS MORE ACTIVE WITH THE SYSTEM...AND IT SHOWS
A WEAKENING SURFACE LOW ASSOCIATED WITH IT. THIS BRINGS LIGHT
PRECIP TO OUR LOCAL AREA IN THE WEDNESDAY NIGHT/THURSDAY TIME
FRAME. THE GFS IS WEAKER WITH THE SYSTEM AND ONLY BRINGS CLOUDS.
HAVE OPTED TO USE A MINIMAL 20 PERCENT POP AT THIS POINT.
ONCE THIS SYSTEM MOVES TO OUR EAST BY THURSDAY NIGHT...MODELS AGREE
ON A SURFACE HIGH PRESSURE SYSTEM BUILDING IN FROM THE NW WITH A
REINFORCING PUSH OF DRY AIR. THIS SHOULD HOLD INTO THE WEEKEND.
LATE IN THE WEEKEND MOISTURE SHOULD BE ON THE INCREASE AGAIN AS
THE HIGH MOVES OFF THE EAST COAST AND LOW PRESSURE DEVELOPS OVER
THE PLAINS...TURNING OUR LOW LEVEL FLOW TO THE SOUTH. HAVE
INCLUDED LOW POPS ON SUNDAY...BUT THE BETTER CHANCE OF PRECIP WILL
BE TO OUR WEST.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 657 AM EDT MON MAY 18 2015
FOG DEVELOPMENT WAS WEAKENED BY THE CLOUDS THAT CONTINUED TO BUILD
ACROSS THE REGION OVERNIGHT INTO THIS MORNING. PATCHY FOG WILL BE
POSSIBLE ACROSS RIVER VALLEYS AND THOSE AREAS THAT RECEIVED RAIN.
A FEW ISOLATED SHOWERS CONTINUE TO POP UP ACROSS PORTIONS OF THE
REGION THIS MORNING AND HAVE INCLUDED VCSH AT A FEW SITES TO
START...BUT ADD TO ALL SITES AS WE MOVE THROUGH THE MORNING.
OTHERWISE BIGGEST ISSUE TODAY WILL BE SHOWERS AND THUNDERSTORMS
DEVELOPING ACROSS EASTERN KENTUCKY THIS AFTERNOON. THE BEST
COVERAGE WILL BE IN THE AFTERNOON WITH DAYTIME HEATING. THEREFORE
DID OPT TO ADD A TEMPO GROUP WITH MVFR VIS TO THE TAF SITES
GENERALLY BETWEEN 18Z AND 19Z. OTHERWISE THINK SITES WILL
GENERALLY KEEP VFR CONDITIONS FOR MUCH OF THE TAF PERIOD. KEPT
WINDS LIGHT TIL THIS AFTERNOON WITH SITES POSSIBLY SEEING GUSTS UP
TO 15 KTS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...DJ
LONG TERM...HAL
AVIATION...DJ
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1004 AM CDT MON MAY 18 2015
.DISCUSSION...
SLOW MOVING MCS ACROSS E TX/C LA WILL BE THE MAIN CONCERN THIS
MORNING...ESPECIALLY FOR FLASH FLOOD POTENTIAL ACROSS THIS REGION.
FOR THIS...ISSUED FLASH FLOOD WATCH FOR TYLER & N JASPER/NEWTON
COUNTIES IN SE TX...AND VERNON/RAPIDES/AVOYELLES PARISHES IN C LA.
HIGH POPS REMAIN FOR THE REST OF THE AFTERNOON FROM THE I-10
CORRIDOR NORTHWARD. FURTHER SOUTH SOUTH OF THE I-10 CORRIDOR...POPS
DROP OFF SIGNIFICANTLY AT THIS TIME...BUT WILL HAVE TO WATCH IF
ANY ADDITIONAL OUTFLOW BOUNDARIES MAY GENERATE PRECIP LATER THIS
EVENING AND OVERNIGHT ACROSS THIS REGION.
DML
&&
.PREV DISCUSSION... /ISSUED 701 AM CDT MON MAY 18 2015/
DISCUSSION...
FOR THE 12Z TAF PACKAGE.
AVIATION...
ISOLATED SHOWERS CONTINUING TO DEVELOP AND STREAM NORTH ACROSS
PARTS OF SOUTH AND EAST CENTRAL LOUISIANA...WITH MORE ROBUST
CONVECTION TO THE NORTH ACROSS NORTH LA...AND FARTHER WEST TO THE
NW OF HOUSTON OVER SE TX. CONDITIONS ACROSS THE REGION RANGE FROM
LIFR AT KAEX TO VFR AT KLCH. PRIMARY CHALLENGE IS CONVECTIVE
EVOLUTION TODAY...WITH THE TEMPO AND PREVAILING THUNDER IN THE TAFS
REPRESENTING A BLEND OF THE LATEST HRRR RUNS AND THE ONLINE SPC
4KM WRF...WHICH DEPICT THE ACTIVITY BOTH TO THE NORTH AND WEST
EVENTUALLY WORKING INTO THE AREA EITHER LATER THIS MORNING OR THIS
AFTERNOON. A MIX OF MVFR AND VFR WILL OTHERWISE PREVAIL WITH CU
GENERALLY IN THE 1500 TO 3500 FT RANGE AND SOUTHERLY WINDS NOT AS
STRONG AND/OR GUSTY AS YESTERDAY.
13
PREV DISCUSSION... /ISSUED 459 AM CDT MON MAY 18 2015/
SYNOPSIS...
LATEST UA ANALYSIS AND WV IMAGERY SHOWS A MOIST SWLY FLOW ALOFT
CONTINUING WITH A BROAD TROF OVER THE WRN CONUS AND A RIDGE OVER THE
SE. A PAIR OF LOWS WERE SPINNING WITHIN THE TROF...ONE CROSSING THE
NRN PLAINS AND ANOTHER ENTERING CA. MEANWHILE...A PERTURBATION
OVERRIDING AN OUTFLOW BOUNDARY LEFT BEHIND FROM LAST NIGHTS MCV
WAS PRODUCING AN INCREASE IN SHOWERS AND THUNDERSTORMS ACRS NRN LA
WITH SCT ACTIVITY DEVELOPING DOWN TO OUR NRN TIER OF PARISHES AND
COUNTIES. AT THE SFC...S-SE WINDS AROUND THE WRN PERIPHERY OF HIGH
PRES OFF THE SE ATL COAST CONTINUE TO STREAM GULF MOISTURE OVER
THE REGION.
DISCUSSION...
MAIN FCST CONCERN IN THE NEAR TERM IS RAIN CHCS AND THE POTENTIAL
FOR HEAVY RAINFALL. CONVECTION ACRS NRN LA INTO E TX WILL CONTINUE
TO INCREASE THROUGH THE MORNING AS SLY/SWLY WINDS SPREAD ABUNDANT
MOISTURE OVER THE REGION. LIFT WILL BE AUGMENTED BY DIFFLUENCE
ALOFT AND LOW LVL FORCING ALONG THE REMNANT BOUNDARY ACRS CNTL LA
AND THIS WILL HELP TO FOCUS THE PRECIPITATION ACRS NRN/CNTL LA.
RECENT HRRR AND NAM PROGS INDICATE CONVECTION SHOULD SLOWLY
PROPAGATE SOUTHWARD DURING THE DAY. AT THIS TIME...THE HIGHEST
RAINFALL TOTALS ARE EXPECTED TO REMAIN NORTH OF THE CWA.
HOWEVER...PRECIP WATER VALUES ARE RUNNING BETWEEN 1.8-2.0 INCHES
OVER THE AREA...MORE THAN ADEQUATE TO PRODUCE EFFICIENT RAINFALL
RATES AND LOCALIZED HEAVY RAIN ESPECIALLY ACRS THE NRN TIER OF
ZONES. HAVE HELD OFF ON ISSUANCE OF A FLASH FLOOD WATCH FOR NOW
WITH FLOODING EXPECTED TO BE MOSTLY LOCALIZED IN NATURE...BUT WILL
NEED TO MONITOR TRENDS FOR POSSIBLY ISSUANCE LATER THIS MORNING.
RAIN CHCS WILL DIMINISH DURING THE EVENING WITH THE LOSS OF
DAYTIME HEATING. A WEAK FRONT WILL SAG SOUTH INTO THE AREA
TUESDAY...BECOMING STALLED NW-SE ACRS NERN TX INTO CNTL LA. THE
PERSISTENT MOIST SWLY FLOW ALOFT AND EMBEDDED DISTURBANCES WILL
AGAIN BRING ABOUT SCT CONVECTION ON TUESDAY. ALTHOUGH COVERAGE IS
EXPECTED TO BE SLIGHTLY LESS THAN TODAY...EXPECT THE HIGHEST POPS
WILL BE CONCENTRATED ALONG THE FRONTAL BOUNDARY ACRS CNTL LA.
WEAK FLAT RIDGING WILL BEGIN TO DEVELOP ALOFT BY
MIDWEEK...HELPING TO REDUCE BUT NOT ELIMINATE SHOWER COVERAGE AND
CHANCES ON WEDNESDAY. ANOTHER FRONT IS FCST TO MOVE INTO THE AREA
THURSDAY...BRINGING ANOTHER ROUND OF SCT SHOWERS AND TSTMS. THE
FRONT WILL STALL NEAR THE COAST FRIDAY THEN SLOWLY RETREAT BACK
NORTH OVER THE WEEKEND. THE RIDGE ALOFT WILL KEEP RAIN CHCS CLOSER
TO 20-30 PERCENT FOR FRIDAY AND SATURDAY...WITH POPS EASING BACK
INTO THE SCT RANGE BY SUNDAY AS THE RIDGE GETS SHIFTED BACK TO THE
EAST OVER THE WEEKEND.
THROUGH THE NEXT FEW DAYS...THE THREAT FOR ANY ORGANIZED SVR
STORMS WILL REMAIN WELL WEST OF THE AREA. HOWEVER...A FEW ISLTD
STORMS COULD PULSE TO STRONG OR MARGINALLY SVR LIMITS DURING THE
AFTN WHEN MAX HEATING CONTRIBUTES TO ENHANCED INSTABILITY. THE
PRIMARY THREAT WILL STILL BE HEAVY RAINFALL AND LOCALIZED FLOODING
IN LOW-LYING OR URBAN AREAS.
LITTLE VARIATION IN TEMPERATURE IS EXPECTED THROUGH NEXT WEEKEND
WITH MAIN IMPACTS TO DAILY TEMPS FROM CLOUDS AND SHOWERS. IN
GENERAL...EXPECT LOWS FROM AROUND 70 INTO THE MIDDLE 70S WHICH IS
ABOUT 5-10 DEGREES ABV NORMAL WHILE HIGHS WILL RUN NEAR NORMAL IN
THE MIDDLE 80S.
24
MARINE...
MODT SELY WINDS WERE OCCURRING OVER THE COASTAL WATERS THIS EARLY
MORNING IN RESPONSE TO ELEVATED WINDS ALOFT AND INFLOW INTO
COMPLEX OF STORMS ACRS NRN LA INTO SE TX. SUSTAINED WINDS HAVE
APPROACHED 20 KNOTS AT TIMES. WITH THIS IN MIND...ADDED EXERCISE
CAUTION HEADLINE TO CWF FOR EARLY THIS MORNING. WINDS WILL
DIMINISH DURING THE MORNING.
OTHERWISE...EXPECT A LT TO MODT ONSHORE FLOW CONTINUING THROUGH
THE WEEK AS HIGH PRES REMAINS EAST OF THE REGION. WIDELY SCT
SHOWERS AND TSTMS WILL BE POSSIBLE THROUGH WEDNESDAY AS A SERIES
OF DISTURBANCES CROSSES THE REGION. CONVECTION WILL BECOME MORE
ISLTD TOWARD THE END OF THE WEEK AS WEAK RIDGING BUILDS IN ALOFT.
24
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 84 68 86 70 / 80 30 40 30
LCH 86 72 86 73 / 50 20 30 20
LFT 87 72 86 72 / 40 20 50 20
BPT 87 75 86 74 / 50 20 20 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR LAZ027>029.
TX...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR TXZ180-259-260.
GM...NONE.
&&
$$
PUBLIC...04
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
701 AM CDT MON MAY 18 2015
.DISCUSSION...
FOR THE 12Z TAF PACKAGE.
&&
.AVIATION...
ISOLATED SHOWERS CONTINUING TO DEVELOP AND STREAM NORTH ACROSS
PARTS OF SOUTH AND EAST CENTRAL LOUISIANA...WITH MORE ROBUST
CONVECTION TO THE NORTH ACROSS NORTH LA...AND FARTHER WEST TO THE
NW OF HOUSTON OVER SE TX. CONDITIONS ACROSS THE REGION RANGE FROM
LIFR AT KAEX TO VFR AT KLCH. PRIMARY CHALLENGE IS CONVECTIVE
EVOLUTION TODAY...WITH THE TEMPO AND PREVAILING THUNDER IN THE TAFS
REPRESENTING A BLEND OF THE LATEST HRRR RUNS AND THE ONLINE SPC
4KM WRF...WHICH DEPICT THE ACTIVITY BOTH TO THE NORTH AND WEST
EVENTUALLY WORKING INTO THE AREA EITHER LATER THIS MORNING OR THIS
AFTERNOON. A MIX OF MVFR AND VFR WILL OTHERWISE PREVAIL WITH CU
GENERALLY IN THE 1500 TO 3500 FT RANGE AND SOUTHERLY WINDS NOT AS
STRONG AND/OR GUSTY AS YESTERDAY.
13
&&
.PREV DISCUSSION... /ISSUED 459 AM CDT MON MAY 18 2015/
SYNOPSIS...
LATEST UA ANALYSIS AND WV IMAGERY SHOWS A MOIST SWLY FLOW ALOFT
CONTINUING WITH A BROAD TROF OVER THE WRN CONUS AND A RIDGE OVER THE
SE. A PAIR OF LOWS WERE SPINNING WITHIN THE TROF...ONE CROSSING THE
NRN PLAINS AND ANOTHER ENTERING CA. MEANWHILE...A PERTURBATION
OVERRIDING AN OUTFLOW BOUNDARY LEFT BEHIND FROM LAST NIGHTS MCV
WAS PRODUCING AN INCREASE IN SHOWERS AND THUNDERSTORMS ACRS NRN LA
WITH SCT ACTIVITY DEVELOPING DOWN TO OUR NRN TIER OF PARISHES AND
COUNTIES. AT THE SFC...S-SE WINDS AROUND THE WRN PERIPHERY OF HIGH
PRES OFF THE SE ATL COAST CONTINUE TO STREAM GULF MOISTURE OVER
THE REGION.
DISCUSSION...
MAIN FCST CONCERN IN THE NEAR TERM IS RAIN CHCS AND THE POTENTIAL
FOR HEAVY RAINFALL. CONVECTION ACRS NRN LA INTO E TX WILL CONTINUE
TO INCREASE THROUGH THE MORNING AS SLY/SWLY WINDS SPREAD ABUNDANT
MOISTURE OVER THE REGION. LIFT WILL BE AUGMENTED BY DIFFLUENCE
ALOFT AND LOW LVL FORCING ALONG THE REMNANT BOUNDARY ACRS CNTL LA
AND THIS WILL HELP TO FOCUS THE PRECIPITATION ACRS NRN/CNTL LA.
RECENT HRRR AND NAM PROGS INDICATE CONVECTION SHOULD SLOWLY
PROPAGATE SOUTHWARD DURING THE DAY. AT THIS TIME...THE HIGHEST
RAINFALL TOTALS ARE EXPECTED TO REMAIN NORTH OF THE CWA.
HOWEVER...PRECIP WATER VALUES ARE RUNNING BETWEEN 1.8-2.0 INCHES
OVER THE AREA...MORE THAN ADEQUATE TO PRODUCE EFFICIENT RAINFALL
RATES AND LOCALIZED HEAVY RAIN ESPECIALLY ACRS THE NRN TIER OF
ZONES. HAVE HELD OFF ON ISSUANCE OF A FLASH FLOOD WATCH FOR NOW
WITH FLOODING EXPECTED TO BE MOSTLY LOCALIZED IN NATURE...BUT WILL
NEED TO MONITOR TRENDS FOR POSSIBLY ISSUANCE LATER THIS MORNING.
RAIN CHCS WILL DIMINISH DURING THE EVENING WITH THE LOSS OF
DAYTIME HEATING. A WEAK FRONT WILL SAG SOUTH INTO THE AREA
TUESDAY...BECOMING STALLED NW-SE ACRS NERN TX INTO CNTL LA. THE
PERSISTENT MOIST SWLY FLOW ALOFT AND EMBEDDED DISTURBANCES WILL
AGAIN BRING ABOUT SCT CONVECTION ON TUESDAY. ALTHOUGH COVERAGE IS
EXPECTED TO BE SLIGHTLY LESS THAN TODAY...EXPECT THE HIGHEST POPS
WILL BE CONCENTRATED ALONG THE FRONTAL BOUNDARY ACRS CNTL LA.
WEAK FLAT RIDGING WILL BEGIN TO DEVELOP ALOFT BY
MIDWEEK...HELPING TO REDUCE BUT NOT ELIMINATE SHOWER COVERAGE AND
CHANCES ON WEDNESDAY. ANOTHER FRONT IS FCST TO MOVE INTO THE AREA
THURSDAY...BRINGING ANOTHER ROUND OF SCT SHOWERS AND TSTMS. THE
FRONT WILL STALL NEAR THE COAST FRIDAY THEN SLOWLY RETREAT BACK
NORTH OVER THE WEEKEND. THE RIDGE ALOFT WILL KEEP RAIN CHCS CLOSER
TO 20-30 PERCENT FOR FRIDAY AND SATURDAY...WITH POPS EASING BACK
INTO THE SCT RANGE BY SUNDAY AS THE RIDGE GETS SHIFTED BACK TO THE
EAST OVER THE WEEKEND.
THROUGH THE NEXT FEW DAYS...THE THREAT FOR ANY ORGANIZED SVR
STORMS WILL REMAIN WELL WEST OF THE AREA. HOWEVER...A FEW ISLTD
STORMS COULD PULSE TO STRONG OR MARGINALLY SVR LIMITS DURING THE
AFTN WHEN MAX HEATING CONTRIBUTES TO ENHANCED INSTABILITY. THE
PRIMARY THREAT WILL STILL BE HEAVY RAINFALL AND LOCALIZED FLOODING
IN LOW-LYING OR URBAN AREAS.
LITTLE VARIATION IN TEMPERATURE IS EXPECTED THROUGH NEXT WEEKEND
WITH MAIN IMPACTS TO DAILY TEMPS FROM CLOUDS AND SHOWERS. IN
GENERAL...EXPECT LOWS FROM AROUND 70 INTO THE MIDDLE 70S WHICH IS
ABOUT 5-10 DEGREES ABV NORMAL WHILE HIGHS WILL RUN NEAR NORMAL IN
THE MIDDLE 80S.
24
MARINE...
MODT SELY WINDS WERE OCCURRING OVER THE COASTAL WATERS THIS EARLY
MORNING IN RESPONSE TO ELEVATED WINDS ALOFT AND INFLOW INTO
COMPLEX OF STORMS ACRS NRN LA INTO SE TX. SUSTAINED WINDS HAVE
APPROACHED 20 KNOTS AT TIMES. WITH THIS IN MIND...ADDED EXERCISE
CAUTION HEADLINE TO CWF FOR EARLY THIS MORNING. WINDS WILL
DIMINISH DURING THE MORNING.
OTHERWISE...EXPECT A LT TO MODT ONSHORE FLOW CONTINUING THROUGH
THE WEEK AS HIGH PRES REMAINS EAST OF THE REGION. WIDELY SCT
SHOWERS AND TSTMS WILL BE POSSIBLE THROUGH WEDNESDAY AS A SERIES
OF DISTURBANCES CROSSES THE REGION. CONVECTION WILL BECOME MORE
ISLTD TOWARD THE END OF THE WEEK AS WEAK RIDGING BUILDS IN ALOFT.
24
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 84 68 86 70 / 70 30 40 30
LCH 86 72 86 73 / 50 20 30 20
LFT 87 72 86 72 / 50 20 50 20
BPT 87 75 86 74 / 50 20 20 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
TX...NONE.
GM...SMALL CRAFT EXERCISE CAUTION UNTIL 9 AM CDT THIS MORNING FOR
GMZ430-432-435-450-452-455-470-472-475.
&&
$$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
948 AM EDT MON MAY 18 2015
.UPDATE...
ISSUED AT 947 AM EDT MON MAY 18 2015
A STRONG COLD FRONT IS OVER EASTERN WI THIS MORNING. TEMPS ARE
PUSHING 70F ALONG THE WI LAKE MI COAST...BUT ARE IN THE LOW 40S IN
THE NW CORNER OF THE STATE. THERE IS NO PRECIP ALONG THE
FRONT...IN FACT THERE IS NO CLOUD COVER ALONG THE FRONT...THOUGH
POST-FRONTAL CLOUD COVER IS SUBSTANTIAL. CLOSER TO HOME...PATCHY
MID/HIGH CLOUDS ARE SEEN OVER NORTHERN MI...A BIT THICKER ACROSS
EASTERN UPPER.
A COUPLE OF POINTS OF CONCERN TODAY. THE COLD FRONT WILL CROSS THE
REGION THIS AFTERNOON. ANY POTENTIAL CONVECTION ALONG IT LOOKS TO
BE CONFINED TO THE EXTREME SE...AS A GENERAL LACK OF FORCING AND
WARM TEMPS ALOFT WILL PROVE A SIGNIFICANT OBSTACLE. WE MIGHT BE
ABLE TO MUSTER 500J/KG OF SBCAPE IN FAR SE SECTIONS. THE MOST
RECENT HRRR AND RUC RUNS DO TRY TO POP SOMETHING EARLY THIS
AFTERNOON...BEFORE DRIER AIR ARRIVES LATER IN THE DAY. HAVE ADDED
A SLIGHT CHANCE OF A SHRA EARLY/MID AFTERNOON FROM OSC TO
STANDISH.
THE OTHER ISSUE IS ANY POTENTIAL FIRE WX CONCERNS. JUST BEHIND A COLD
FRONT IS A CLASSIC SUMMER FIRE WX PATTERN FOR US...AS WITH STRONG
HEATING WE TEND TO DRY OUT FASTER THAN WE COOL OFF. HOWEVER...
IDEALLY COLD FROPA WOULD HAPPEN A FEW HOURS EARLIER...IN THE
MORNING AS OPPOSED TO THE PM. HAVE LOWERED DEW POINTS A BIT DURING
THE AFTERNOON...BUT HAVE ALSO DONE THE SAME TO LATE-DAY TEMPS AS
THE COOLER AIR MAKES INITIAL INROADS. SO DON/T HAVE RH LEVELS
GOING BELOW 35 PERCENT OR SO.
&&
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 319 AM EDT MON MAY 18 2015
ALL REMAINING SHOWERS HAVE EXITED NE OUT OF OUR CWA EARLY THIS
MORNING...WITH NO ADDITIONAL SHOWER ACTIVITY CURRENTLY PRESENT
UPSTREAM AS THE WRN GREAT LAKES REMAINS FIRMLY WITHIN THE DRY SLOT
ASSOCIATED WITH DEEP LOW PRESSURE NOW CENTERED OVER NRN MINNESOTA.
SKIES HAVE AT LEAST PARTIALLY CLEARED IN RESPONSE TO THIS DRIER AIR
WORKING ITS WAY INTO MICHIGAN. OUR CWA WILL REMAIN WITHIN THE DRY
SLOT THRU MUCH OF TODAY AS THE SURFACE LOW CENTER MAKES SLOW
EASTWARD PROGRESS THRU UPPER MICHIGAN AND INTO QUEBEC BY 00Z
TUESDAY. EXPECT A PARTLY TO MOSTLY SUNNY AND DRY DAY ALONG WITH
UNSEASONABLY WARM TEMPS FOR MOST OF OUR CWA. AFTERNOON HIGHS WILL
ONLY REACH TO AROUND 70 DEGREES ACROSS ERN UPR MICHIGAN WHERE CAA ON
THE BACKSIDE OF THE LOW WILL INITIALLY BEGIN THIS AFTERNOON. BUT
TEMPS WILL ONCE AGAIN WARM INTO THE UPPER 70S AND LOWER 80S FOR NRN
LWR MICHIGAN (COOLER NEAR THE LAKES)...GIVING US ONE LAST DAY OF
SUMMER WARMTH BEFORE THE REALITY OF NRN MICHIGAN IN MID MAY KICKS
BACK IN ON TUESDAY.
LOW LEVEL MOISTURE/CLOUDS WILL WRAP BACK INTO NRN MICHIGAN TONIGHT
ON THE BACKSIDE OF THE DEPARTING LOW. THE CAA BEHIND THE LOW WILL BE
RAPID AND IMPRESSIVE THRU THE NIGHT...AS 850 MB TEMPS DROP FROM +13C
THIS AFTERNOON TO AROUND -2C BY 12Z TUESDAY. AT THIS POINT...THINK
THE ONLY LOCATION THAT WILL SEE A CHANCE OF SHOWERS WILL BE NW
CHIPPEWA COUNTY THIS AFTERNOON AND TONIGHT WHERE CAA AND LOW LEVEL
WRAP AROUND MOISTURE ADVECTION TAKE PLACE SOONEST. THE REST OF OUR
CWA SHOULD BE GENERALLY DRY...BUT WITH DEEP CYCLONIC FLOW...
INCREASING LOW LEVEL MOISTURE AND EVENTUALLY SOME OVER-LAKE
INSTABILITY DEVELOPING LATE TONIGHT THANKS TO CAA...WILL NEED TO
KEEP AN EYE ON THE POTENTIAL FOR SOME SHOWER ACTIVITY TO DEVELOP.
FOR NOW...WILL MAINTAIN A DRY FORECAST WITH INCREASING CLOUDS
TONIGHT. TEMPS WILL BE NOTICEABLY COLDER TONIGHT...WITH LOWS FALLING
MAINLY INTO THE 40S.
&&
.SHORT TERM...(TUESDAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 319 AM EDT MON MAY 18 2015
HIGH IMPACT WEATHER: TUESDAY NIGHT LOW TEMPERATURES/FROST POTENTIAL
FOR N LOWER.
FORECAST CHALLENGE: HOW FAR WILL THE TEMPERATURES FALL TUESDAY
NIGHT.
(05/19)TUESDAY...WITH THE FRONT SEVERAL HUNDRED MILES TO THE EAST,
THE COLD AIR WILL BE PUSHING INTO THE REGION THROUGH THE DAY.
TEMPERATURES WILL PRETTY MUCH GO NO WHERE AS THE 850 MB TEMPERATURES
FALL FROM AROUND 0C TO ABOUT -4 OR -6C DEPENDING ON THE MODEL. THE
ECMWF IS BEGINNING TO BACK OFF ON THE -8C AIR THAT IT WAS
ADVERTISING THE LAST 2 RUNS, WITH IT AROUND -6C AT ANJ. WHILE THE
GFS WILL BE AROUND -4C. WILL HAVE A MIX OF RAIN AND SNOW IN THE
AFTERNOON AS THE SFC TEMPERATURES BEGIN TO FALL INTO THE UPPER 30S
BY IN E UPPER. THE MOISTURE DOESN`T LOOK DEEP ENOUGH FOR
PRECIPITATION IN N LOWER SO WILL LEAVE IT OUT OF THERE, JUST MOSTLY
CLOUDY. OVERNIGHT, THE RH AT 850 MB AND IN THE 700-500 MB LAYER WILL
DROP TO LESS THAN 20% ON BOTH MODELS BY 12Z. AND WITH THE 850 MB
TEMPERATURES MAINTAINING AROUND 0C OR BELOW, AND, AT LEAST ON THE
ECMWF, THE WINDS WILL PROBABLY DECOUPLE, FROST IS PROBABLE, AND
MAYBE A FREEZE IS POSSIBLE. FOR NOW WILL HAVE PATCHY AND AREAS OF
FROST, BUT THIS IS LOOKING MORE WIDE SPREAD IF THE WINDS DROP OFF
LIKE THE ECMWF WOULD SUGGEST.
(05/20)WEDNESDAY...LOOKS TO BE A SUNNY TO PARTLY CLOUDY DAY WITH LOW
RELATIVE HUMIDITY AND HIGH TEMPERATURES, BELOW NORMAL (LOOKS LIKE
NOW AROUND 5 TO 10 DEGREES BELOW) IF THE MODELS PAN OUT. OVERNIGHT,
A 500 MB SHORTWAVE PUSHES THROUGH THE FORECAST AREA, BUT THE MODELS
SUGGEST THAT ONLY THE MOISTURE IN THE 700-500 MB LAYER WOULD
INCREASE, IF ANY AT ALL. SO WILL EXPECT THAT THE NIGHT WOULD REMAIN
DRY. MAY IDEAS IS THAT THE SKY REMAINS CLEAR TO PARTLY CLOUDY, SO
TEMPERATURES LOOK TO BE IN THE LOWER TO MID 30S, SO ANOTHER FROST
NIGHT? PUT PATCHY IN FOR THE INLAND AREAS, AND LEFT THE LAKE SHORES
FROST FREE WHERE THE AIR TEMPERATURE IS EXPECTED TO BE A LITTLE
WARMER.
&&
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 319 AM EDT MON MAY 18 2015
EXTENDED (THURSDAY THROUGH SUNDAY)...WITH THE 500 MB TROUGH THAT
PARKS ITSELF OVER THE NEW ENGLAND STARTING TUESDAY AND HANGS THERE
THROUGH FRIDAY. FRIDAY, THE LOW BEGINS TO MOVE OUT ALLOWING THE 500
MB RIDGE TO BUILD IN THE UPPER GREAT LAKES. SO WHAT DOES THIS MEAN
FOR THE LONG TERM? SFC HIGH PRESSURE WILL CAMP OUT IN THE UPPER
GREAT LAKES THROUGH THE WEEK, KEEPING THE AREA DRY THROUGH SATURDAY
NIGHT, AND THE 500 MB PATTERN WILL KEEP THE HIGH TEMPERATURES AROUND
OR BELOW NORMAL THROUGH THE WEEK WHEN THE NORMAL HIGH TEMPERATURES
IN GAYLORD AND SAULT STE. MARIE ARE IN THE UPPER 60S. SUNDAY, THE
MODELS BEGIN TO KEY IN ON THE NEXT 500 MB LOW THAT MOVES OUT OF THE
CENTRAL ROCKIES AND INTO THE CENTRAL PLAINS, PRODUCING SHOWERS AND
POSSIBLY THUNDERSTORMS AS THE WARM FRONT PUSHES UP THROUGH THE
STATE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY)
ISSUED AT 700 AM EDT MON MAY 18 2015
VFR CONDITIONS ARE EXPECTED AT ALL NRN LWR MICHIGAN TAF SITES
THRU TODAY AS THE DRY SLOT (ASSOCIATED WITH DEEP LOW PRESSURE
JUST WEST OF MICHIGAN) REMAINS OVERHEAD. A LARGE AREA OF LOW LEVEL
MOISTURE WILL WRAP BACK INTO NRN MICHIGAN TONIGHT AS THE SURFACE
LOW RIDES EAST THRU MICHIGAN AND THEN EXITS INTO QUEBEC. SW SURFACE
WINDS AROUND 10 KTS WILL SHIFT TO THE W/NW THIS EVENING.
&&
.MARINE...
ISSUED AT 319 AM EDT MON MAY 18 2015
WINDS AND WAVES WILL APPROACH SCA CRITERIA TODAY AND ESPECIALLY
TONIGHT AS CAA DEVELOPS ON THE WAKE OF A DEPARTING LOW. AT THIS
POINT...EXPECT CONDITIONS SHOULD REMAIN UNDER CRITERIA...SO WILL
NOT ISSUE A SCA AT THIS TIME. STRONGER NW WINDS WILL LIKELY DEVELOP
ON TUESDAY AS CAA STRENGTHENS BEHIND THE DEPARTING LOW. AREAS OF FOG
AND LOW STRATUS WILL CONTINUE TO IMPACT OUR NEARSHORE AREAS THRU
THIS MORNING BEFORE MIXING OUT THIS AFTERNOON.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&
$$
UPDATE...JAZ
NEAR TERM...MLR
SHORT TERM...JSL
LONG TERM...JSL
AVIATION...MLR
MARINE...MLR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
751 AM EDT MON MAY 18 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 508 AM EDT MON MAY 18 2015
WATER VAPOR LOOP AND RAP ANALYSIS SHOWS MID-LVL LOW ROTATING OVER
NRN MN WITH A DRY SLOT AHEAD OF LOW REACHING ACROSS MUCH OF THE
UPPER MI. COLD FRONT MOVING ACROSS MUCH OF THE AREA OVERNIGHT HAS
ALLOWED DRIER AIR TO ADVECT IN FROM THE SW WHICH HAS DISSIPATED THE
DENSE FOG OVER LAKE MI AND AREAS DOWNSTREAM OVER ERN UPPER MI. DRY
SLOT HAS LEFT UPPER MI GENERALLY PCPN FREE OVER THE EARLY MORNING
HRS.
TODAY AND TONIGHT...THE FOCUS TODAY WILL ON COLD SURGE WHICH WILL BE
MOVING INTO THE WEST MID-LATE MORNING AND CONTINUE EASTWARD THROUGH
THE DAY. AHEAD OF THE FRONT OVER THE EAST HALF OF UPPER MI AND AWAY
FROM THE MODERATING INFLUENCE OF LAKE MICHIGAN...SHOULD SEE
TEMPERATURES REACH IN THE MID TO UPPER 60S (WITH A FEW 70S POSSIBLE
IF THERE ARE BREAKS IN THE LOW CLOUDS). OVER THE WEST HALF WHERE
FRONTAL PASSAGE WILL OCCUR EARLIER...MORNING TO EARLY AFTERNOON HIGH
TEMPS WILL RANGE FROM UPPER 40S/50F NEAR IRONWOOD TO LOWER 60S ALONG
A LINE FM MQT TO MENOMINEE. IN ADDITION...ALL OF THE HIGHER
RESOLUTION MODELS ARE SURGING IN A LAKE BREEZE OFF LAKE SUPERIOR
(FROM MARQUETTE EASTWARD) WHICH WILL LEAD TO COOLER NORTHERLY FLOW
BY MID-LATE AFTERNOON OVER NCNTRL AREAS. WITH THE COLD AIR AND
ABUNDANT MOISTURE SURGING INTO THE AREA AS WINDS TURN
WESTERLY...EXPECT ISOLATED TO SCATTERED SHOWERS TO DEVELOP OVER THE
WEST FIRST (ESPECIALLY IN THE FAVORED UPSLOPE AREAS) AND THEN SPREAD
INTO THE CENTRAL AREAS EVENING AND POSSIBLY EASTERN COUNTIES LATE
EVENING/OVERNIGHT. CAA ON BLUSTERY NW TO N WINDS WILL ALLOW 8H TEMPS
TO FALL TO -8 TO -10C OVER MUCH OF THE WEST HALF OF UPPER MI BY 12Z
TUE. 8H TEMPS WILL FALL TO AROUND -5C OVER THE EAST HALF OVERNIGHT.
BEST FORCING OUT AHEAD ANOTHER SHORTWAVE TRACKING ALONG THE
MN/ONTARIO BORDER TONIGHT WILL STAY MAINLY NW OF UPPER MI KEEPING
MUCH OF THE ASSOCIATED LIGHT PCPN N OF UPPER MI. HOWEVER...DEEP
CYCLONIC FLOW/MOISTURE WILL STILL SUPPORT SOME LIGHT PCPN IN UPPER
MI AS WELL...ESPECIALLY IN THE UPSLOPE AREAS OF THE W AND N. WITH
COLD ADVECTION TAKING PLACE AS NOTED BEFORE...THE -SHRA WILL MIX
WITH OR CHANGE TO -SHSN TONIGHT FROM WEST TO EAST. DUE TO THE COLD
ADVECTION AND PCPN OCCURRING DURING THE OVERNIGHT HOURS...CAN`T RULE
OUT A DUSTING TO LOCALLY A HALFINCH OF SNOW ON GRASSY SFCS BY 12Z
TUE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON MAY 18 2015
TUESDAY WILL BRING ABOUT ONLY SLOWLY RISING TEMPS AS A SECONDARY
TROUGH/COLD FRONT SINKING ACROSS CENTRAL TO E UPPER MI. 850MB TEMPS
AT A CHILLY -10C OVER THE KEWEENAW PENINSULA /2-5C WARMER OFF THE
17/18Z AND 18/00Z GFS RUNS...AS WELL AS THE REGIONAL WRF/. THE NAM
IS THE COLDEST WITH THE ENTIRE W HALF AROUND -11C TUESDAY MORNING.
850MB TEMPS WILL FALL FROM AROUND -4C AT ERY TO AROUND -9C BY 18Z
TUESDAY ON NW WINDS. THIS WILL BE AS ANOTHER SHORTWAVE OVER NE MN AT
12Z SLIDES ACROSS LAKE SUPERIOR. YES...SNOW IS POSSIBLE STILL ON
TUESDAY...BUT MAY BE LIMITED TO JUST A DUSTING ON MAINLY GRASSY
SURFACES THROUGH THE MORNING HOURS...BEFORE THE LOW LEVEL RH
DIMINISHES SIGNIFICANTLY.
EXPECT BREEZY CONDITIONS...WITH GUSTS AVERAGING 20-25KTS ACROSS MUCH
OF THE CWA...STRONGEST ACROSS THE KEWEENAW PENINSULA AND E NEAR LAKE
SUPERIOR. DESPITE LIGHT W FLOW RETURNING AT THE SFC TUESDAY NIGHT
AND 850MB TEMPS WARMING TO AROUND 0C...LOWS NEAR TO SLIGHTLY BELOW
FREEZING WILL BE POSSIBLE /COLDEST IN THE TRADITIONAL COOL SPOTS OF
THE INTERIOR W HALF OF UPPER MI/.
EXPECT DRIER CONDITIONS WITH LIGHTER WINDS WEDNESDAY AS SFC TEMPS
REBOUND TO AROUND 60F. THIS WILL BE DESPITE THE 500MB TROUGH WITH
ITS NW FLOW LINGERING OVERHEAD...AS THE LARGE SFC HIGH OVER THE
DAKOTAS BUILDS A RIDGE ACROSS UPPER MI. PW VALUES SHOULD BE AROUND
0.25IN FROM OVERNIGHT TUESDAY NIGHT THROUGH MUCH OF WEDNESDAY
/ALTHOUGH SLIGHTLY HIGHER NEAR LAKE MI FROM LATE MORNING ON/.
DRY WEATHER SHOULD REMAIN THROUGH THE REST OF THE WORK WEEK AT NW
FLOW LINGERS AT 500MB. THERE WILL BE A WEAK COLD FRONT STRETCHING
ACROSS N LAKE SUPERIOR AT 00Z THURSDAY THAT SINKS ACROSS UPPER MI
WEDNESDAY EVENING AND LOWER MI DURING THE DAY THURSDAY. NOT
EXPECTING MUCH MORE THAN THE POSSIBILITY OF TEMPORARY ADDITIONAL
CLOUD COVER. HIGH PRESSURE WILL SLIDE IN BEHIND THE FRONTAL BOUNDARY
TO WRAP UP THE END OF THE WORK WEEK. EXPECT THIS HIGH TO SHIFT TO
THE LOWER GREAT LAKES BY 18Z SATURDAY AND OFF THE MID-ATLANTIC COAST
SUNDAY MORNING. THIS EXITING HIGH WILL ALLOW MOISTURE TO
RETURN...ALONG WITH A GOOD CHANCE OF SHOWERS FOR SUNDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 743 AM EDT MON MAY 18 2015
WRAPAROUND MOISTURE BEGINNING TO ARRIVE AT THE WRN TAF SITES WILL
PRODUCE SOME SCT RAIN SHOWERS THIS AFTERNOON AT IWD AND CMX UNDER
MVFR CONDITIONS. DRY AIR WILL KEEP KSAW VFR UNTIL LATE MORNING WHEN
MOISTURE AND BANK OF STRATU MOVES IN FROM THE SW...THEN COULD SEE A
PERIOD OF MVFR CIGS. PUSH OF COLDER AIR BEHIND SECONDARY COLD FRONT
WILL CHANGE RAIN SHOWERS AT KIWD AND KCMX OVER TO SNOW SHOWERS THIS
EVENING WITH IFR CONDITIONS DEVELOPING. SCT -SHRA DEVELOPING AT KSAW
EARLY EVENING WILL ALSO CHANGE OVER TO -SHSN LATE TONIGHT WITH
POSSIBLE IFR CONDITIONS DEVELOPING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EDT MON MAY 18 2015
LOW PRES OVER NRN MN WILL MOVE ACROSS LAKE SUPERIOR TODAY INTO THIS
EVENING. AS A RESULT...WINDS ON LAKE SUPERIOR WILL VEER FM SW THIS
MORNING TO NNW LATE TODAY AND TONIGHT AND RAMP UP TO 20 TO 30 KTS
TONIGHT AND TUE...STRONGEST OVER THE EAST HALF. NOT OUT OF THE
QUESTION THAT THERE COULD BE SOME GALE FORCE GUSTS OVER THE E HALF
OF THE LAKE LATE TONIGHT/TUE MORNING. WINDS WILL DIMINISH W TO E TUE
AFTN/NIGHT AS A HIGH PRES RIDGE BUILDS IN FM THE WEST. WED THRU
FRI...WINDS WILL BE UNDER 20KT. LINGERING WARM MOIST AIR WILL ALLOW
FOG TO CONTINUE OVER THE LAKE TODAY...POSSIBLE LOCALLY DENSE OVER
THE EAST HALF THIS MORNING. ALL FOG SHOULD DISSIPATE BY THIS EVENING
AS COLDER AIR ARRIVES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
757 AM EDT MON MAY 18 2015
.SYNOPSIS...
A WARM AND HUMID AIR MASS WILL REMAIN OVER THE REGION WITH A PERIOD
OF SHOWERS AND THUNDERSTORMS PUSHING ACROSS WESTERN AND CENTRAL NEW
YORK TODAY AHEAD OF A COLD FRONT. SOME OF THESE THUNDERSTORMS MAY
BRING LOCALIZED HEAVY RAIN. THE FRONT WILL CROSS EARLY TUESDAY THEN
A COOLER AND DRIER AIRMASS WILL ARRIVE BEHIND THE FRONT FOR THE
REMAINDER OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
THE FORECAST AREA LIES BENEATH AN AMPLIFIED 500MB RIDGE THIS MORNING
WITH STACKED SURFACE AND UPPER LEVEL LOW OVER THE MINNESOTA
ARROWHEAD CONTINUING TO SPREAD WARM AND MOIST AIR NORTH ACROSS THE
GREAT LAKES. DEWPOINTS RISING INTO THE MID 60S ACROSS WESTERN NEW
YORK AS A RIBBON OF HIGH PRECIPITABLE WATER VALUES AROUND 1.7 INCHES
/NEAR MAX ON MID MAY SOUNDING CLIMO/ RUNNING FROM NORTH OF GEORGIAN
BAY TO LAKE ERIE. PLENTY OF MOISTURE TO BE FOUND SO FOCUS FOR TIMING
OF SHOWER AND THUNDERSTORM ACTIVITY TODAY WILL BE ON ANY
SYNOPTIC/MESOSCALE FEATURES SHIFTING ACROSS THE EASTERN GREAT LAKES.
A PRE-FRONTAL TROUGH IS ANALYZED ROUGHLY FROM NORTHERN MI SOUTHEAST
TO NEAR KERI. THIS IS FORECAST TO SHIFT ACROSS WESTERN AND CENTRAL
NEW YORK TODAY. LOOKING TO THE MID-LEVELS...FORCING MAY ALSO COME
FROM ANY SUBTLE SHORTWAVES ROLLING UP THE WEST SIDE OF THE RIDGE
AXIS FROM THE MISS VALLEY TOWARD THE EASTERN GREAT LAKES. MESOSCALE
GUIDANCE SUCH AS WRF AND HRRR MODELS SUGGEST A FEW ISOLATED SHOWERS
AND STORMS MAY WORK INTO WNY ALONG THE TROUGH THIS MORNING. BY EARLY
AFTERNOON FORECAST CAPE OF 2-3K J/KG WILL FEED MORE NUMEROUS SHOWERS
AND THUNDERSTORMS DEVELOPING FROM THE SOUTHERN TIER ACROSS THE
GENESEE VALLEY AND FINGER LAKES. A STABLE SOUTHWEST FLOW OFF LAKE
ERIE SHOULD KEEP MUCH OF THE NIAGARA FRONTIER PROTECTED FROM THE
HEAVIER STORMS BUT LAKE BREEZES COULD TRIGGER ADDITIONAL CELLS TO THE
SOUTH AND EAST OF BUFFALO. BULK SHEAR THIS AFTERNOON IS FORECAST
ONLY AROUND 15 KTS SO TOO WEAK TO SUPPORT ANY SIGNIFICANT WIND/HAIL
THREAT. THE DEEP MOISTURE IN PLACE PER PWATS AND SKINNY CAPE
PROFILES WITH SLOW STORM MOTIONS WILL HOWEVER BRING A RISK FOR
LOCALLY HEAVY RAIN AND FLOODING IF ANY TRAINING CELLS DEVELOPS.
TONIGHT...THE SURFACE LOW WILL SHIFT NORTH OF THE GREAT LAKES TO
SOUTHERN QUEBEC. NEAR-TERM MODELS INDICATE THE MAJORITY OF REMAINING
CONVECTION WILL BE LIMITED FROM THE FINGER LAKES EASTWARD ACROSS
CENTRAL AND EASTERN NEW YORK. WESTERN NEW YORK WILL LARGELY REMAIN
DRY. THE COLD FRONT WILL CROSS WNY LATE TONIGHT AND IS FORECAST TO
BE NEAR THE FINGER LAKES BY 12Z TUESDAY WITH SKY COVER THINNING FROM
WEST TO EAST. THE OVERNIGHT TIMING OF THE FRONT SHOULD LIMIT A
SECOND ROUND OF SHOWER/TSTM ACTIVITY.
TEMPERATURES TODAY WILL AGAIN RISE ABOVE NORMAL WITHIN A HUMID
AIRMASS. 850MB TEMPS OF NEAR +15C WILL SUPPORT SURFACE HIGH TEMPS
RANGING FROM THE UPPER 70S TO MID 80S. THE U70S TEMPS WILL ONLY BE
LIMITED BY EARLIER START TO CONVECTION WHILE MORE HEATING ACROSS
FINGER LAKES AND NORTH COUNTRY WILL HELP BOOST TEMPS TO THE M80S.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
A STRONG COLD FRONT WILL CROSS THE FORECAST AREA DURING THE DAY ON
TUESDAY. WHILE THE BULK OF THE PRECIPITATION WILL BE ASSOCIATED WITH
THE PRE-FRONTAL TROUGH AND ALREADY WELL TO THE EAST OF THE FORECAST
AREA OVER THE ADIRONDACKS/GREEN MOUNTAINS BY TUESDAY MORNING...A FEW
SHOWERS WILL STILL BE POSSIBLE ALONG/JUST AHEAD OF THE COLD
FRONT...PARTICULARLY ACROSS THE NORTH COUNTRY WHERE THE APPROACH OF
THE COLD FRONT WILL COINCIDE WITH THE AFTERNOON DIURNAL HEATING
MAXIMUM.
OTHERWISE...LOOK FOR BREEZY CONDITIONS WITH FALLING TEMPERATURES
BEHIND THE COLD FRONT. A PERIOD OF POST-FRONTAL SUBSIDENCE AND
SUNSHINE WILL GIVE WAY TO INCREASING CLOUDS LATER IN THE DAY AND
INTO THE EVENING AS THE UPPER LEVEL TROUGH SWINGS THROUGH.
TEMPERATURES WILL CONTINUE TO FALL INTO THE 40S TUESDAY NIGHT...WITH
HIGHER ELEVATIONS DIPPING JUST BELOW THE 40 DEGREE MARK AS THE CORE
OF THE COLD AIR ALOFT MOVES ACROSS THE REGION. WITH 850MB TEMPS
FALLING BELOW -2C...WE MAY EVEN SEE A DECENT AMOUNT OF LAKE-ENHANCED
CLOUD COVER TUESDAY NIGHT AND INTO WEDNESDAY MORNING. THIS COLD AIR
ALOFT AND THE ASSOCIATED CLOUD COVER WILL AID IN MAKING WEDNESDAY
THE COLDEST DAY OF THIS WEEK WITH HIGHS ONLY TOPPING OUT IN THE LOW
TO MID 50S.
BY WEDNESDAY AFTERNOON WE SHOULD SEE AN INCREASE IN SUNSHINE ONCE
MORE AS THE COLDEST AIR ALOFT IS QUICKLY SHUNTED OFF TO THE EAST AS
A FLATTER AND FASTER PATTERN TAKES SHAPE IN THE UPPER LEVELS AND
SURFACE RIDING BEGINS TO CREEP IN ACROSS THE AREA FROM THE UPPER
MIDWEST. A FAST-MOVING SHORTWAVE SHOULD BRING SOME CLOUD COVER TO
THE SOUTHERN TIER WEDNESDAY NIGHT BUT HAVE LITTLE OTHER IMPACT
OWING TO A DEARTH OF MOISTURE. LOWS ONCE AGAIN WILL RUN IN THE
40S...WITH A FEW UPPER 30S IN THE SOUTHERN TIER. IT NOW APPEARS THAT
THERE SHOULD BE ENOUGH OF A BREEZE BOTH TUESDAY AND WEDNESDAY NIGHTS
TO PRECLUDE THE DEVELOPMENT OF FROST IN THE SOUTHERN TIER/NORTH
COUNTRY IN SPITE OF TEMPERATURES THAT WILL BE DIPPING INTO THE 30S.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
IT WILL BE A DRY DAY ON THURSDAY WITH PASSING HIGH CLOUDS AS THE
REGION WILL REMAIN UNDERNEATH THE FLATTENED BASE OF A DEEP UPPER
LEVEL LOW CENTERED NEAR JAMES BAY. THE UPPER LEVEL FLOW WILL AMPLIFY
ONCE MORE ACROSS THE AREA ON FRIDAY AS A JET MAX DROPS INTO THE BASE
OF THE TROUGH OVER NORTHEASTERN ONTARIO. THIS WILL HELP PUSH ANOTHER
WEAK COLD FRONT ACROSS UPSTATE AND WESTERN NEW YORK ON
FRIDAY...POTENTIALLY TRIGGERING A SHOWER OR TWO ACROSS THE NORTH
COUNTRY. HOWEVER...A LACK OF MOISTURE WILL ONCE AGAIN LIMIT POPS TO
A SLIGHT CHANCE AT BEST.
AN EVEN MORE BENIGN PATTERN TAKES SHAPE FOR THE COMING WEEKEND AS
SURFACE HIGH PRESSURE TRACKS OVER THE LOWER GREAT LAKES. THERE WILL
BE PLENTY OF SUNSHINE TO BE HAD FRIDAY AND SATURDAY AS THE HIGH
MOVES OVERHEAD BEFORE MOVING OFF THE EAST COAST SUNDAY. AS THE HIGH
MOVES OFF THE EAST COAST...LOOK FOR RETURN FLOW TO SET UP ACROSS THE
LOWER GREAT LAKES THAT WILL SIGNAL A RETURN TO WARMER CONDITIONS
SUNDAY WITH UNSETTLED WEATHER LIKELY TO FOLLOW BY MONDAY AS A WARM
FRONT LIFTS NORTH ACROSS THE GREAT LAKES.
REGARDING TEMPERATURES...READINGS WILL RUN IN THE 60S ON THURSDAY.
WHILE CERTAINLY WARMER THAN THE CHILLY 50S EXPECTED WEDNESDAY...THE
LOWER GREAT LAKES REGION WILL REMAIN CLOSE ENOUGH TO THE
AFOREMENTIONED UPPER LEVEL LOW TO KEEP TEMPERATURES A FEW DEGREES
BELOW NORMAL. INDEED THE PASSAGE OF THE WEAK COOL FRONT FRIDAY WILL
KNOCK TEMPS BACK A COUPLE OF DEGREES. WITH HIGH PRESSURE MOVING
BUILDING FRIDAY NIGHT AND COOL/DRY AIR IN PLACE...WE SHOULD SEE A
CHILLY NIGHT WITH LOWS IN THE LOW/MID 40S...WITH UPPER 30S IN THE
SOUTHERN TIER AND NORTH COUNTRY. THIS TIME WINDS MAY BE LIGHT ENOUGH
TO POTENTIALLY ALLOW FOR FROST ACROSS THE SHELTERED AREAS OF THE
NORTH COUNTRY AND THE SOUTHERN TIER. THEREAFTER...TEMPERATURES
SHOULD GRADUALLY REBOUND THROUGH THE WEEKEND AS THE HIGH DRIFTS EAST
OF THE REGION AND RETURN FLOW TAKES HOLD WITH WIDESPREAD 70S
EXPECTED ONCE AGAIN BY SUNDAY.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS IN PLACE EARLY THIS MORNING EXCEPT FOR SOME IFR FOG
ACROSS THE HILLTOPS OF THE SOUTHERN TIER. THIS WILL WILL DISSIPATE
IN THE MORNING WITH INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS
FOR KJHW/KROC/KART DURING THE LATE MORNING AND AFTERNOON AS A PRE-
FRONTAL TROUGH CROSSES THE FORECAST AREA. A STABLE FLOW OFF LAKE
ERIE SHOULD KEEP KBUF/KIAG FREE FROM ANY HEAVY STORMS WHICH WILL
DEVELOP FROM THE SOUTHERN TIER TO EAST OF BUFFALO TO ROCHESTER AND
SYRACUSE. STORM ACTIVITY WILL SHIFT EAST LATER THIS EVENING WITH
MAINLY DRY CONDITIONS EXPECTED TONIGHT. SOME LOW CLOUDS/FOG MAY
BRING IFR TO KJHW LATE TONIGHT ESPECIALLY IF HEAVY RAIN FALLS
ACROSS THE SOUTHERN TIER.
OUTLOOK...
TUESDAY THROUGH FRIDAY...VFR.
&&
.MARINE...
LIGHT WINDS AND MINIMAL WAVES WILL CONTINUE ON THE EASTERN GREAT
LAKES TODAY WITH AREAS OF FOG AS A WARM AND HUMID AIRMASS REMAINS
OVER THE COOL LAKE WATERS. CONDITIONS ON THE LAKES SHOULD REMAIN
QUIET OUTSIDE OF ANY THUNDERSTORMS PRODUCING ASSOCIATED HIGHER WINDS
AND WAVES.
A COLD FRONT WILL SWEEP ACROSS THE EASTERN GREAT LAKES LATE
TONIGHT/TUESDAY WITH AN INCREASE IN WIND SPEED AND WAVE ACTION INTO
TUESDAY. A SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE LAKE ERIE
NEARSHORES COVERING TUESDAY AFTERNOON/EVENING. HIGH PRESSURE WILL
THEN BUILD OVER THE EASTERN GREAT LAKES WEDNESDAY THROUGH THE REST
OF THE WEEK WITH LOW WIND AND WAVE ACTION.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TO 11 PM EDT TUESDAY FOR LEZ040-
041.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...WOOD
LONG TERM...WOOD
AVIATION...SMITH
MARINE...SMITH
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1108 AM EDT MON MAY 18 2015
.SYNOPSIS...
WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT
IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD
FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON.
&&
.NEAR TERM /THROUGH TONIGHT/...
NO UPDATES TO THE NEAR TERM OTHER THAN TO TWEAK POPS BASED ON
CURRENT TRENDS.
PREVIOUS DISCUSSION BELOW...
LATEST RADAR MOSAIC AND SURFACE OBSERVATIONS SUGGEST REGION IS
GENERALLY DRY AT THIS TIME. EXPECT THESE CONDITIONS WILL CONTINUE
THROUGH THE OVERNIGHT HOURS...AND HAVE SLIGHT CHANCE POPS
CONTINUING.
LATEST HRRR SHOWS A SMALL AREA OF SHOWERS...CURRENTLY OVER SOUTHEAST
KENTUCKY...WILL SPREAD NORTHEAST AND INCREASE IN AREAL COVERAGE AS
IT MOVES INTO OUR SOUTHERN COUNTIES LATER THIS MORNING. THE CURRENT
TREND OF THESE SHOWERS HAS BEEN TO WEAKEN. SO NOT SURE HOW MUCH OF
THESE SHOWERS WILL ACTUALLY MAKE IT INTO OUR AREA.
MOST OF THE MODELS THEN INDICATE WEAK DISTURBANCES WILL MOVE ACROSS
THE AREA TODAY INTO TONIGHT. COMBINATION OF THESE DISTURBANCES AND
INCREASING INSTABILITY SHOULD ONCE AGAIN RESULT IN THE DEVELOPMENT
OF SHOWERS AND STORMS TODAY.
LOCALIZED DOWNPOURS ARE ONCE AGAIN POSSIBLE TODAY AND TONIGHT...AND
CAN RESULT IN MINOR FLOODING OF STREETS...CREEKS...LOW LYING AND
POOR DRAINAGE AREAS.
WITH THE LOSS OF DAYTIME HEATING...THE COVERAGE AND INTENSITY OF
THE CONVECTION SHOULD BEGIN TO WANE. HOWEVER...A COLD FRONT...WHICH
IS EXPECTED TO PUSH INTO THE REGION LATE TONIGHT...SHOULD CONTINUE
THE THREAT OF SHOWERS AND STORMS.
CURRENT THINKING IS THAT THE FRONT SHOULD BE LOCATED NEAR OR JUST
EAST OF THE OHIO RIVER AT THE END OF THIS PERIOD.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
MADE NO REAL CHANGES WITH THE SHORT TERM PART OF THE FORECAST.
RAISED POPS A BIT IN THE EAST MONDAY NIGHT AHEAD OF THE COLD
FRONT. PW VALUES ARE IN THE 1.5-1.75 INCHES RANGE AHEAD THE FRONT
SO THE PROSPECT OF HEAVY RAIN OVERNIGHT IS STILL POSSIBLE. EVEN
WITH ALL OF THE RAIN THAT HAS FALLEN UP TO THIS POINT THE GROUND
SHOULD BE ABLE TO HANDLE THE SITUATION SO NO REAL CONCERNS. WILL
CONTINUE TO MONITOR THE SITUATION. IT DRIES OUT QUICKLY BEHIND THE
FRONT STARTING TUESDAY NIGHT.
DRY WEATHER WITH PLEASANT TEMPERATURES SHOULD PREVAIL TUESDAY
NIGHT AND WEDNESDAY AS WEAK HIGH PRESSURE BUILDS TO THE WEST
GIVING ZONAL FLOW FOR THE OHIO VALLEY.
WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE
PERIOD.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
NOTHING SIGNIFICANT TO FOCUS ON IN THE LONG TERM. HIGH PRESSURE
BUILDS OVER THE CENTRAL US AND THAT WILL LEAVE ZONAL FLOW OVER THE
OHIO VALLEY. THE EXTENDED FORECAST WILL BE DRY FOR THE MOST PART
BUT CONFIDENCE IS NOT ALL THAT HIGH AS THERE COULD BE A FEW UPPER
LEVEL RIPPLES CAUSED BY THE WEAK FRONT THAT PASSES TO THE NORTH
NEXT WEEKEND. PRECIPITATION CHANCES INCREASING ON SUNDAY.
WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
12Z MONDAY THRU 12Z TUESDAY...
CONDITIONS HAVE IMPROVED SINCE 09Z...WITH MOST LOCATIONS MVFR OR
BETTER. HOWEVER...ISOLATED IFR CONDITIONS MAY STILL BE OCCURRING
ALONG RIVER VALLEYS.
LATEST RADAR SHOWS ISOLATED SHOWERS HAVE BEGUN TO DEVELOP ACROSS
PORTIONS OF SOUTHEAST OHIO AND NORTHEAST KENTUCKY. THESE SHOWER
WERE DEVELOPING IN RESPONSE TO AN UPPER LEVEL DISTURBANCE.
EXPECT THESE SHOWERS WILL CONTINUE TO SPREAD ACROSS THE REMAINDER
OF THE STATE...AS THE DISTURBANCE MOVES NORTHEAST..
ADDITIONAL DISTURBANCES ARE EXPECTED TO MOVE ACROSS THE AREA TODAY...
WHICH WILL RESULT IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS...
ESPECIALLY FOR THE AFTERNOON AND EVENING HOURS. WHILE MOST LOCATIONS
WILL SEE VFR OR MVFR CONDITIONS...EXPECT IFR CONDITIONS ARE POSSIBLE
NEAR THE HEAVIER STORMS. GUSTY WINDS ARE ALSO POSSIBLE NEAR THE
STRONGER STORMS.
THE STORMS SHOULD THEN WEAKEN AFTER 23Z. HOWEVER...SCATTERED STORMS
WILL REMAIN POSSIBLE THROUGH THE END OF THE PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: COVERAGE OF STORMS COULD HIGHER THAN
EXPECTED...WITH ORE AREAS SEEING IFR OR LOWER CONDITIONS THIS
AFTERNOON AND EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21
CRW CONSISTENCY H H H H H H M M M M H H
HTS CONSISTENCY H H H M M M H H M H H H
BKW CONSISTENCY H H H H H H H H M M M M
EKN CONSISTENCY L M M H M H H H M M M M
PKB CONSISTENCY H H H H H H H H M H H H
CKB CONSISTENCY H H H H H H H H M M M M
AFTER 12Z TUESDAY...
BRIEF IFR IN SHOWERS AND THUNDERSTORMS POSSIBLE IN LOW CLOUDS TUE
MORNING. FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT INTO WED
MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/ARJ
NEAR TERM...JSH/KMC
SHORT TERM...FB
LONG TERM...FB
AVIATION...JSH
AREA FORECAST DISCUSSION...UPDATED
NWS CLEVELAND OH
901 AM EDT MON MAY 18 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST ACROSS THE AREA THIS EVENING. HIGH
PRESSURE WILL BUILD VERY SLOWLY EAST AND SETTLE INTO THE MID
MISSISSIPPI VALLEY REGION BY THURSDAY. THE HIGH WILL EXTEND A RIDGE
EAST ACROSS THE LOCAL AREA DURING THIS TIME. MORE HIGH PRESSURE WILL
BUILD SOUTHEAST OUT OF CANADA AND MERGE WITH THE EXISTING HIGH
PRESSURE AND BECOME CENTERED OVER OHIO BY SATURDAY MORNING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
REMOVED ALL POPS FOR REMAINDER OF MORNING. BUMPED UP TEMPS ALONG
THE EASTERN ERIE LAKESHORE DUE TO UPSLOPE FLOW. REMAINDER OF
FORECAST LOOKS REASONABLE.
ORIGINAL DISCUSSION...
WITH SUNRISE...SHOWERS ARE TRYING TO DEVELOP IN THE WESTERN HALF
OF THE FORECAST AREA. WILL KEEP A CHANCE FOR SHOWERS OVER THE
WESTERN HALF THIS MORNING AND THEN EXPAND IT OVER THE REST OF THE
AREA BY THE AFTERNOON. LATEST HRRR MODEL SHOWS THE SHOWER ACTIVITY
OVER SOUTHERN INDIANA GRADUALLY LIFTING NORTHEAST INTO THE REGION
WITH TIME. BUMPED MAX TEMPERATURES UP A COUPLE DEGREES IN THE
CENTRAL PORTIONS AS LATEST GUIDANCE IS COMING IN A COUPLE DEGREES
WARMER.
PREVIOUS DISCUSSION...
NONE OF THE INGREDIENTS APPEAR TO BE IN PHASE TODAY TO PRODUCE
WIDESPREAD SHOWERS AND THUNDERSTORMS. FIRST...UPPER LEVEL POSITIVE
VORTICITY ADVECTION WILL MOVE EAST ACROSS THE AREA TODAY. THERE WILL
BE SOME MOISTURE ASSOCIATED WITH THIS UPPER LEVEL FEATURE.
HOWEVER...THE COLD FRONT IS LAGGING BACK QUITE A BIT AND WILL NOT BE
IN PHASE WITH THE UPPER LEVEL ACTIVITY. SO TIMING OF THE THREAT FOR
SHOWERS AND THUNDERSTORMS COULD BE A BIT ON THE IFFY SIDE THROUGH
THE DAY. WILL KEEP THE MENTION OF SCATTERED SHOWERS AND
THUNDERSTORMS OVER MUCH OF THE AREA. BEST CHANCE WILL LIKELY BE
LATER IN THE DAY IN THE EAST WITH DAY TIME HEATING AND LINGERING
POSITIVE VORTICITY ADVECTION AND APPROACHING COLD FRONT. SO WILL GO
LIKELY POPS OVER THAT AREA FOR THIS AFTERNOON AND EVENING.
WARM AIR ADVECTION STILL TAKING PLACE IN THE WARM SECTOR ACROSS THE
FORECAST AREA. SINCE THE GREATEST THREAT FOR SHOWERS AND
THUNDERSTORMS WILL OCCUR IN THE EAST...TEMPERATURES MAY BE HELD BACK
A TAD COMPARED TO THE WEST. SO WILL LEAN TOWARD AROUND 80 IN THE
EAST AND 80 TO 84 IN THE WEST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
COLD FRONT FINALLY ARRIVES AND IS EXPECTED TO SWEEP EAST ACROSS THE
FORECAST AREA FROM WEST TO EAST BETWEEN 00Z AND 06Z TONIGHT. DRY
SLOT IS EXPECTED TO RACE NORTH AHEAD OF THE FRONT INTO THE AREA AS
WELL LIMITING THE EFFECTS FRONT HAS ON PRODUCING SHOWERS AND
THUNDERSTORMS. FRONT PUSHES EAST LATE TONIGHT DIMINISHING THREAT FOR
SHOWERS AS WELL AS NEGATIVE VORTICITY ADVECTION AND DRIER AIR MOVE
INTO THE REGION.
HIGH PRESSURE RIDGE BUILDS EAST INTO THE AREA TUESDAY THROUGH
WEDNESDAY AND BRINGS A RETURN BACK TO FAIR WEATHER ONCE AGAIN.
NOW...THIS IS WHERE THE MODELS SHOW SOME DIFFERENCES. NAM IS THE
WETTEST WEDNESDAY NIGHT IN FORCING A FAST MOVING UPPER LEVEL
POSITIVE VORTICITY MAXIMUM EAST INTO THE AREA. THIS FEATURE HAS
QUITE A BIT OF MOISTURE WITH IT. THE GFS IS SHOWING A SIMILAR
SOLUTION BUT IS LIMITED IN MOISTURE WHERE AS THE SREF SHUNTS
EVERYTHING SOUTH. SINCE THERE ARE SO MANY DIFFERENCES IN TIMING AND
AREAL EXTENT OF THE PRECIPITATION THREAT...WILL JUST MENTION A
SLIGHT CHANCE FOR SHOWERS AT THIS TIME AND SEE IF THE MODELS CAN
COME TO SOME KIND OF CONSENSUS.
UPPER LEVEL FEATURE PULLS OUT TO THE EAST THURSDAY AND BRINGS A
RETURN BACK TO FAIR WEATHER THURSDAY AFTERNOON AND NIGHT.
THE BAD NEWS IS THAT CHILLY AIR WILL RETURN BEHIND THE COLD FRONT
DROPPING TEMPERATURES BACK INTO THE 50S FOR HIGHS ACROSS THE
NORTHERN TIER COUNTIES BY WEDNESDAY AND LOWER 60S ACROSS THE SOUTH.
OVERNIGHT LOWS WILL DROP INTO THE 40S. A BIT OF A REBOUND WITH MORE
SUN WILL RETURN ON THURSDAY WITH HIGHS IN THE LOWER TO MIDDLE 60S.
YET LOWS WILL STILL BE IN THE 40S THURSDAY NIGHT. NOT EXPECTING ANY
FROST THROUGH THE PERIOD AT THIS TIME.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
THE LONG TERM BEGINS FRIDAY WITH A COLD FRONT HAVING JUST DROPPED
SOUTH ACROSS THE REGION AND AN UNREASONABLE AMOUNT OF COLD AIR JUST
TO OUR NORTH. DURING THE DAY HIGH PRESSURE WILL BUILD IN FROM THE
WEST AND WHILE TEMPS WILL BE ON THE COOL SIDE...BOTH MODELS TAKE THE
CORE OF THE COLD AIR EAST ACROSS QUEBEC AND NORTHERN NEW ENGLAND.
SATURDAY THE HIGH MOVES EAST AND HEIGHTS BEGIN TO RECOVER AS WARMER
AIR BEGINS TO RETURN TO THE REGION. AN UPPER RIDGE WILL BE MOVING
INTO THE MIDWEST HOWEVER A SURFACE LOW IN THE CENTRAL PLAINS WILL
BEING DEEP MOISTURE INTO THE MID MISSISSIPPI VALLEY UNDER THE
RIDGE. BY SATURDAY NIGHT AND SUNDAY THIS MOISTURE WILL LIKELY BE
SPILLING INTO THE AREA WITH DEEP SOUTHERLY FLOW INTO THE AREA AHEAD
OF A DEVELOPING UPPER TROF IN THE PLAINS. WILL KEEP FORECAST DRY
THROUGH SATURDAY NIGHT BUT BRING MID/HIGH CHANCE POPS IN FOR
SUNDAY. WILL HAVE LIKELY POPS NORTHWEST SUNDAY NIGHT AND MONDAY
WHICH MAY NEED TO BE EXPANDED AS THE FORECAST EVOLVES. TEMPS FRIDAY
FROM THE UPPER 50S NORTHEAST LAKESHORE TO THE LOWER 70S SOUTHWEST.
MOST AREAS WILL SEE LOWER AND MID 70S SATURDAY AND SUNDAY.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AIRMASS QUITE MOIST THIS MORNING WITH DEWPOINTS IN THE MID 60S
STILL CONDITIONS REMAIN PRIMARILY VFR ACROSS THE AREA. UPPER
RIDGE JUST EAST OF THE AREA CONTINUES TO KEEP A LID ON CONVECTION.
FOR TODAY...ASIDE FROM PATCHY MVFR EARLY...EXPECTING MOSTLY VFR
CONDITIONS INTO THE AFTERNOON. FOLLOWING THE HRRR...DO EXPECT
SCATTERED SHOWERS/POSSIBLY THUNDER TO DEVELOP AND DRIFT ACROSS
CENTRAL AND EASTERN TERMINALS...MAINLY INLAND FROM ABOUT 16-20Z.
WILL LIKELY SEE ANOTHER SHOT OF SHOWERS/TSTMS THROUGH THE EVENING
AND/OR OVERNIGHT WITH MVFR CONDITIONS AHEAD OF THE APPROACHING
COLD FRONT. DRIEST AIR IS IN THE NORTHWEST SO DID NOT BRING
CONVECTION THERE. OTHERWISE VCTS/VCSH. POST FRONT EXPECT A RETURN
TO VFR ALTHOUGH GIVING TIMING INLAND EAST WILL LIKELY END THE
FORECAST PERIOD REMAIN MVFR.
.OUTLOOK... NON-VFR POSSIBLE BEHIND A COLD FRONT IN NE OH/NW PA
TUESDAY NIGHT.
&&
.MARINE...
LOW PRESSURE OVER LAKE SUPERIOR WILL MOVE NORTHEAST ACROSS ONTARIO
TO QUEBEC TODAY. A COLD FRONT EXTENDING SOUTHWEST FROM THE LOW WILL
CROSS LAKE ERIE TONIGHT. SOUTH TO SOUTHWEST FLOW TODAY AND TONIGHT
WILL REMAIN FAIRLY LIGHT. TUESDAY WINDS WILL INCREASE FROM THE WEST
AND SOUTHWEST TO 15 TO 25 KNOTS/ WINDS WILL TURN NORTHWEST TUESDAY
NIGHT AS THE COLD AIR DEEPENS ACROSS THE LAKE. A LARGE AREA OF HIGH
PRESSURE WILL BUILD TOWARD THE LAKE MID WEEK AS IT DROPS INTO THE
CENTRAL PLAINS. ANOTHER COLD FRONT HOWEVER WILL APPROACH FROM THE
NORTH THURSDAY LIKELY DROPPING ACROSS THE LAKE THURSDAY NIGHT OR
EARLY FRIDAY. NO GALES ARE EXPECTED THROUGH THE PERIOD HOWEVER A
SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED SOMETIME TUESDAY AS WINDS
INCREASE...CONTINUING TUESDAY NIGHT AND MOST OF WEDNESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...DJB/LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...TK
AVIATION...TK
MARINE...TK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
727 AM EDT MON MAY 18 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST ACROSS THE AREA THIS EVENING. HIGH
PRESSURE WILL BUILD VERY SLOWLY EAST AND SETTLE INTO THE MID
MISSISSIPPI VALLEY REGION BY THURSDAY. THE HIGH WILL EXTEND A RIDGE
EAST ACROSS THE LOCAL AREA DURING THIS TIME. MORE HIGH PRESSURE WILL
BUILD SOUTHEAST OUT OF CANADA AND MERGE WITH THE EXISTING HIGH
PRESSURE AND BECOME CENTERED OVER OHIO BY SATURDAY MORNING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WITH SUNRISE...SHOWERS ARE TRYING TO DEVELOP IN THE WESTERN HALF
OF THE FORECAST AREA. WILL KEEP A CHANCE FOR SHOWERS OVER THE
WESTERN HALF THIS MORNING AND THEN EXPAND IT OVER THE REST OF THE
AREA BY THE AFTERNOON. LATEST HRRR MODEL SHOWS THE SHOWER ACTIVITY
OVER SOUTHERN INDIANA GRADUALLY LIFTING NORTHEAST INTO THE REGION
WITH TIME. BUMPED MAX TEMPERATURES UP A COUPLE DEGREES IN THE
CENTRAL PORTIONS AS LATEST GUIDANCE IS COMING IN A COUPLE DEGREES
WARMER.
PREVIOUS DISCUSSION...
NONE OF THE INGREDIENTS APPEAR TO BE IN PHASE TODAY TO PRODUCE
WIDESPREAD SHOWERS AND THUNDERSTORMS. FIRST...UPPER LEVEL POSITIVE
VORTICITY ADVECTION WILL MOVE EAST ACROSS THE AREA TODAY. THERE WILL
BE SOME MOISTURE ASSOCIATED WITH THIS UPPER LEVEL FEATURE.
HOWEVER...THE COLD FRONT IS LAGGING BACK QUITE A BIT AND WILL NOT BE
IN PHASE WITH THE UPPER LEVEL ACTIVITY. SO TIMING OF THE THREAT FOR
SHOWERS AND THUNDERSTORMS COULD BE A BIT ON THE IFFY SIDE THROUGH
THE DAY. WILL KEEP THE MENTION OF SCATTERED SHOWERS AND
THUNDERSTORMS OVER MUCH OF THE AREA. BEST CHANCE WILL LIKELY BE
LATER IN THE DAY IN THE EAST WITH DAY TIME HEATING AND LINGERING
POSITIVE VORTICITY ADVECTION AND APPROACHING COLD FRONT. SO WILL GO
LIKELY POPS OVER THAT AREA FOR THIS AFTERNOON AND EVENING.
WARM AIR ADVECTION STILL TAKING PLACE IN THE WARM SECTOR ACROSS THE
FORECAST AREA. SINCE THE GREATEST THREAT FOR SHOWERS AND
THUNDERSTORMS WILL OCCUR IN THE EAST...TEMPERATURES MAY BE HELD BACK
A TAD COMPARED TO THE WEST. SO WILL LEAN TOWARD AROUND 80 IN THE
EAST AND 80 TO 84 IN THE WEST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
COLD FRONT FINALLY ARRIVES AND IS EXPECTED TO SWEEP EAST ACROSS THE
FORECAST AREA FROM WEST TO EAST BETWEEN 00Z AND 06Z TONIGHT. DRY
SLOT IS EXPECTED TO RACE NORTH AHEAD OF THE FRONT INTO THE AREA AS
WELL LIMITING THE EFFECTS FRONT HAS ON PRODUCING SHOWERS AND
THUNDERSTORMS. FRONT PUSHES EAST LATE TONIGHT DIMINISHING THREAT FOR
SHOWERS AS WELL AS NEGATIVE VORTICITY ADVECTION AND DRIER AIR MOVE
INTO THE REGION.
HIGH PRESSURE RIDGE BUILDS EAST INTO THE AREA TUESDAY THROUGH
WEDNESDAY AND BRINGS A RETURN BACK TO FAIR WEATHER ONCE AGAIN.
NOW...THIS IS WHERE THE MODELS SHOW SOME DIFFERENCES. NAM IS THE
WETTEST WEDNESDAY NIGHT IN FORCING A FAST MOVING UPPER LEVEL
POSITIVE VORTICITY MAXIMUM EAST INTO THE AREA. THIS FEATURE HAS
QUITE A BIT OF MOISTURE WITH IT. THE GFS IS SHOWING A SIMILAR
SOLUTION BUT IS LIMITED IN MOISTURE WHERE AS THE SREF SHUNTS
EVERYTHING SOUTH. SINCE THERE ARE SO MANY DIFFERENCES IN TIMING AND
AREAL EXTENT OF THE PRECIPITATION THREAT...WILL JUST MENTION A
SLIGHT CHANCE FOR SHOWERS AT THIS TIME AND SEE IF THE MODELS CAN
COME TO SOME KIND OF CONSENSUS.
UPPER LEVEL FEATURE PULLS OUT TO THE EAST THURSDAY AND BRINGS A
RETURN BACK TO FAIR WEATHER THURSDAY AFTERNOON AND NIGHT.
THE BAD NEWS IS THAT CHILLY AIR WILL RETURN BEHIND THE COLD FRONT
DROPPING TEMPERATURES BACK INTO THE 50S FOR HIGHS ACROSS THE
NORTHERN TIER COUNTIES BY WEDNESDAY AND LOWER 60S ACROSS THE SOUTH.
OVERNIGHT LOWS WILL DROP INTO THE 40S. A BIT OF A REBOUND WITH MORE
SUN WILL RETURN ON THURSDAY WITH HIGHS IN THE LOWER TO MIDDLE 60S.
YET LOWS WILL STILL BE IN THE 40S THURSDAY NIGHT. NOT EXPECTING ANY
FROST THROUGH THE PERIOD AT THIS TIME.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
THE LONG TERM BEGINS FRIDAY WITH A COLD FRONT HAVING JUST DROPPED
SOUTH ACROSS THE REGION AND AN UNREASONABLE AMOUNT OF COLD AIR JUST
TO OUR NORTH. DURING THE DAY HIGH PRESSURE WILL BUILD IN FROM THE
WEST AND WHILE TEMPS WILL BE ON THE COOL SIDE...BOTH MODELS TAKE THE
CORE OF THE COLD AIR EAST ACROSS QUEBEC AND NORTHERN NEW ENGLAND.
SATURDAY THE HIGH MOVES EAST AND HEIGHTS BEGIN TO RECOVER AS WARMER
AIR BEGINS TO RETURN TO THE REGION. AN UPPER RIDGE WILL BE MOVING
INTO THE MIDWEST HOWEVER A SURFACE LOW IN THE CENTRAL PLAINS WILL
BEING DEEP MOISTURE INTO THE MID MISSISSIPPI VALLEY UNDER THE
RIDGE. BY SATURDAY NIGHT AND SUNDAY THIS MOISTURE WILL LIKELY BE
SPILLING INTO THE AREA WITH DEEP SOUTHERLY FLOW INTO THE AREA AHEAD
OF A DEVELOPING UPPER TROF IN THE PLAINS. WILL KEEP FORECAST DRY
THROUGH SATURDAY NIGHT BUT BRING MID/HIGH CHANCE POPS IN FOR
SUNDAY. WILL HAVE LIKELY POPS NORTHWEST SUNDAY NIGHT AND MONDAY
WHICH MAY NEED TO BE EXPANDED AS THE FORECAST EVOLVES. TEMPS FRIDAY
FROM THE UPPER 50S NORTHEAST LAKESHORE TO THE LOWER 70S SOUTHWEST.
MOST AREAS WILL SEE LOWER AND MID 70S SATURDAY AND SUNDAY.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AIRMASS QUITE MOIST THIS MORNING WITH DEWPOINTS IN THE MID 60S
STILL CONDITIONS REMAIN PRIMARILY VFR ACROSS THE AREA. UPPER
RIDGE JUST EAST OF THE AREA CONTINUES TO KEEP A LID ON CONVECTION.
FOR TODAY...ASIDE FROM PATCHY MVFR EARLY...EXPECTING MOSTLY VFR
CONDITIONS INTO THE AFTERNOON. FOLLOWING THE HRRR...DO EXPECT
SCATTERED SHOWERS/POSSIBLY THUNDER TO DEVELOP AND DRIFT ACROSS
CENTRAL AND EASTERN TERMINALS...MAINLY INLAND FROM ABOUT 16-20Z.
WILL LIKELY SEE ANOTHER SHOT OF SHOWERS/TSTMS THROUGH THE EVENING
AND/OR OVERNIGHT WITH MVFR CONDITIONS AHEAD OF THE APPROACHING
COLD FRONT. DRIEST AIR IS IN THE NORTHWEST SO DID NOT BRING
CONVECTION THERE. OTHERWISE VCTS/VCSH. POST FRONT EXPECT A RETURN
TO VFR ALTHOUGH GIVING TIMING INLAND EAST WILL LIKELY END THE
FORECAST PERIOD REMAIN MVFR.
.OUTLOOK... NON-VFR POSSIBLE BEHIND A COLD FRONT IN NE OH/NW PA
TUESDAY NIGHT.
&&
.MARINE...
LOW PRESSURE OVER LAKE SUPERIOR WILL MOVE NORTHEAST ACROSS ONTARIO
TO QUEBEC TODAY. A COLD FRONT EXTENDING SOUTHWEST FROM THE LOW WILL
CROSS LAKE ERIE TONIGHT. SOUTH TO SOUTHWEST FLOW TODAY AND TONIGHT
WILL REMAIN FAIRLY LIGHT. TUESDAY WINDS WILL INCREASE FROM THE WEST
AND SOUTHWEST TO 15 TO 25 KNOTS/ WINDS WILL TURN NORTHWEST TUESDAY
NIGHT AS THE COLD AIR DEEPENS ACROSS THE LAKE. A LARGE AREA OF HIGH
PRESSURE WILL BUILD TOWARD THE LAKE MID WEEK AS IT DROPS INTO THE
CENTRAL PLAINS. ANOTHER COLD FRONT HOWEVER WILL APPROACH FROM THE
NORTH THURSDAY LIKELY DROPPING ACROSS THE LAKE THURSDAY NIGHT OR
EARLY FRIDAY. NO GALES ARE EXPECTED THROUGH THE PERIOD HOWEVER A
SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED SOMETIME TUESDAY AS WINDS
INCREASE...CONTINUING TUESDAY NIGHT AND MOST OF WEDNESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...TK
AVIATION...TK
MARINE...TK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
645 AM EDT MON MAY 18 2015
.SYNOPSIS...
WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT
IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD
FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON.
&&
.NEAR TERM /THROUGH TONIGHT/...
LATEST RADAR MOSAIC AND SURFACE OBSERVATIONS SUGGEST REGION IS
GENERALLY DRY AT THIS TIME. EXPECT THESE CONDITIONS WILL CONTINUE
THROUGH THE OVERNIGHT HOURS...AND HAVE SLIGHT CHANCE POPS CONTINUING.
LATEST HRRR SHOWS A SMALL AREA OF SHOWERS...CURRENTLY OVER SOUTHEAST
KENTUCKY...WILL SPREAD NORTHEAST AND INCREASE IN AREAL COVERAGE AS
IT MOVES INTO OUR SOUTHERN COUNTIES LATER THIS MORNING. THE CURRENT
TREND OF THESE SHOWERS HAS BEEN TO WEAKEN. SO NOT SURE HOW MUCH OF
THESE SHOWERS WILL ACTUALLY MAKE IT INTO OUR AREA.
MOST OF THE MODELS THEN INDICATE WEAK DISTURBANCES WILL MOVE ACROSS
THE AREA TODAY INTO TONIGHT. COMBINATION OF THESE DISTURBANCES AND
INCREASING INSTABILITY SHOULD ONCE AGAIN RESULT IN THE DEVELOPMENT
OF SHOWERS AND STORMS TODAY.
LOCALIZED DOWNPOURS ARE ONCE AGAIN POSSIBLE TODAY AND TONIGHT...AND
CAN RESULT IN MINOR FLOODING OF STREETS...CREEKS...LOW LYING AND
POOR DRAINAGE AREAS.
WITH THE LOSS OF DAYTIME HEATING...THE COVERAGE AND INTENSITY OF
THE CONVECTION SHOULD BEGIN TO WANE. HOWEVER...A COLD FRONT...WHICH
IS EXPECTED TO PUSH INTO THE REGION LATE TONIGHT...SHOULD CONTINUE
THE THREAT OF SHOWERS AND STORMS.
CURRENT THINKING IS THAT THE FRONT SHOULD BE LOCATED NEAR OR JUST
EAST OF THE OHIO RIVER AT THE END OF THIS PERIOD.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
MADE NO REAL CHANGES WITH THE SHORT TERM PART OF THE FORECAST.
RAISED POPS A BIT IN THE EAST MONDAY NIGHT AHEAD OF THE COLD
FRONT. PW VALUES ARE IN THE 1.5-1.75 INCHES RANGE AHEAD THE FRONT
SO THE PROSPECT OF HEAVY RAIN OVERNIGHT IS STILL POSSIBLE. EVEN
WITH ALL OF THE RAIN THAT HAS FALLEN UP TO THIS POINT THE GROUND
SHOULD BE ABLE TO HANDLE THE SITUATION SO NO REAL CONCERNS. WILL
CONTINUE TO MONITOR THE SITUATION. IT DRIES OUT QUICKLY BEHIND THE
FRONT STARTING TUESDAY NIGHT.
DRY WEATHER WITH PLEASANT TEMPERATURES SHOULD PREVAIL TUESDAY
NIGHT AND WEDNESDAY AS WEAK HIGH PRESSURE BUILDS TO THE WEST
GIVING ZONAL FLOW FOR THE OHIO VALLEY.
WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE
PERIOD.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
NOTHING SIGNIFICANT TO FOCUS ON IN THE LONG TERM. HIGH PRESSURE
BUILDS OVER THE CENTRAL US AND THAT WILL LEAVE ZONAL FLOW OVER THE
OHIO VALLEY. THE EXTENDED FORECAST WILL BE DRY FOR THE MOST PART
BUT CONFIDENCE IS NOT ALL THAT HIGH AS THERE COULD BE A FEW UPPER
LEVEL RIPPLES CAUSED BY THE WEAK FRONT THAT PASSES TO THE NORTH
NEXT WEEKEND. PRECIPITATION CHANCES INCREASING ON SUNDAY.
WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
12Z MONDAY THRU 12Z TUESDAY...
CONDITIONS HAVE IMPROVED SINCE 09Z...WITH MOST LOCATIONS MVFR OR
BETTER. HOWEVER...ISOLATED IFR CONDITIONS MAY STILL BE OCCURRING
ALONG RIVER VALLEYS.
LATEST RADAR SHOWS ISOLATED SHOWERS HAVE BEGUN TO DEVELOP ACROSS
PORTIONS OF SOUTHEAST OHIO AND NORTHEAST KENTUCKY. THESE SHOWER
WERE DEVELOPING IN RESPONSE TO AN UPPER LEVEL DISTURBANCE.
EXPECT THESE SHOWERS WILL CONTINUE TO SPREAD ACROSS THE REMAINDER
OF THE STATE...AS THE DISTURBANCE MOVES NORTHEAST..
ADDITIONAL DISTURBANCES ARE EXPECTED TO MOVE ACROSS THE AREA TODAY...
WHICH WILL RESULT IN THE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS...
ESPECIALLY FOR THE AFTERNOON AND EVENING HOURS. WHILE MOST LOCATIONS
WILL SEE VFR OR MVFR CONDITIONS...EXPECT IFR CONDITIONS ARE POSSIBLE
NEAR THE HEAVIER STORMS. GUSTY WINDS ARE ALSO POSSIBLE NEAR THE
STRONGER STORMS.
THE STORMS SHOULD THEN WEAKEN AFTER 23Z. HOWEVER...SCATTERED STORMS
WILL REMAIN POSSIBLE THROUGH THE END OF THE PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: COVERAGE OF STORMS COULD HIGHER THAN
EXPECTED...WITH ORE AREAS SEEING IFR OR LOWER CONDITIONS THIS
AFTERNOON AND EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS
CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18
CRW CONSISTENCY L H H H H H H H H M M M
HTS CONSISTENCY H H H H H H M M M H H M
BKW CONSISTENCY H H H H H H H H H H H M
EKN CONSISTENCY L M L L H H H M H H H M
PKB CONSISTENCY H H H H H H H H H H H M
CKB CONSISTENCY H H H H M H H H H H H M
AFTER 12Z TUESDAY...
BRIEF IFR IN SHOWERS AND THUNDERSTORMS POSSIBLE IN LOW CLOUDS TUE
MORNING. FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT INTO WED
MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/ARJ
NEAR TERM...JSH
SHORT TERM...FB
LONG TERM...FB
AVIATION...JSH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
635 AM EDT MON MAY 18 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST ACROSS THE AREA THIS EVENING. HIGH
PRESSURE WILL BUILD VERY SLOWLY EAST AND SETTLE INTO THE MID
MISSISSIPPI VALLEY REGION BY THURSDAY. THE HIGH WILL EXTEND A RIDGE
EAST ACROSS THE LOCAL AREA DURING THIS TIME. MORE HIGH PRESSURE WILL
BUILD SOUTHEAST OUT OF CANADA AND MERGE WITH THE EXISTING HIGH
PRESSURE AND BECOME CENTERED OVER OHIO BY SATURDAY MORNING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WITH SUNRISE...SHOWERS ARE TRYING TO DEVELOP IN THE WESTERN HALF
OF THE FORECAST AREA. WILL KEEP A CHANCE FOR SHOWERS OVER THE
WESTERN HALF THIS MORNING AND THEN EXPAND IT OVER THE REST OF THE
AREA BY THE AFTERNOON. LATEST HRRR MODEL SHOWS THE SHOWER ACTIVITY
OVER SOUTHERN INDIANA GRADUALLY LIFTING NORTHEAST INTO THE REGION
WITH TIME. BUMPED MAX TEMPERATURES UP A COUPLE DEGREES IN THE
CENTRAL PORTIONS AS LATEST GUIDANCE IS COMING IN A COUPLE DEGREES
WARMER.
PREVIOUS DISCUSSION...
NONE OF THE INGREDIENTS APPEAR TO BE IN PHASE TODAY TO PRODUCE
WIDESPREAD SHOWERS AND THUNDERSTORMS. FIRST...UPPER LEVEL POSITIVE
VORTICITY ADVECTION WILL MOVE EAST ACROSS THE AREA TODAY. THERE WILL
BE SOME MOISTURE ASSOCIATED WITH THIS UPPER LEVEL FEATURE.
HOWEVER...THE COLD FRONT IS LAGGING BACK QUITE A BIT AND WILL NOT BE
IN PHASE WITH THE UPPER LEVEL ACTIVITY. SO TIMING OF THE THREAT FOR
SHOWERS AND THUNDERSTORMS COULD BE A BIT ON THE IFFY SIDE THROUGH
THE DAY. WILL KEEP THE MENTION OF SCATTERED SHOWERS AND
THUNDERSTORMS OVER MUCH OF THE AREA. BEST CHANCE WILL LIKELY BE
LATER IN THE DAY IN THE EAST WITH DAY TIME HEATING AND LINGERING
POSITIVE VORTICITY ADVECTION AND APPROACHING COLD FRONT. SO WILL GO
LIKELY POPS OVER THAT AREA FOR THIS AFTERNOON AND EVENING.
WARM AIR ADVECTION STILL TAKING PLACE IN THE WARM SECTOR ACROSS THE
FORECAST AREA. SINCE THE GREATEST THREAT FOR SHOWERS AND
THUNDERSTORMS WILL OCCUR IN THE EAST...TEMPERATURES MAY BE HELD BACK
A TAD COMPARED TO THE WEST. SO WILL LEAN TOWARD AROUND 80 IN THE
EAST AND 80 TO 84 IN THE WEST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
COLD FRONT FINALLY ARRIVES AND IS EXPECTED TO SWEEP EAST ACROSS THE
FORECAST AREA FROM WEST TO EAST BETWEEN 00Z AND 06Z TONIGHT. DRY
SLOT IS EXPECTED TO RACE NORTH AHEAD OF THE FRONT INTO THE AREA AS
WELL LIMITING THE EFFECTS FRONT HAS ON PRODUCING SHOWERS AND
THUNDERSTORMS. FRONT PUSHES EAST LATE TONIGHT DIMINISHING THREAT FOR
SHOWERS AS WELL AS NEGATIVE VORTICITY ADVECTION AND DRIER AIR MOVE
INTO THE REGION.
HIGH PRESSURE RIDGE BUILDS EAST INTO THE AREA TUESDAY THROUGH
WEDNESDAY AND BRINGS A RETURN BACK TO FAIR WEATHER ONCE AGAIN.
NOW...THIS IS WHERE THE MODELS SHOW SOME DIFFERENCES. NAM IS THE
WETTEST WEDNESDAY NIGHT IN FORCING A FAST MOVING UPPER LEVEL
POSITIVE VORTICITY MAXIMUM EAST INTO THE AREA. THIS FEATURE HAS
QUITE A BIT OF MOISTURE WITH IT. THE GFS IS SHOWING A SIMILAR
SOLUTION BUT IS LIMITED IN MOISTURE WHERE AS THE SREF SHUNTS
EVERYTHING SOUTH. SINCE THERE ARE SO MANY DIFFERENCES IN TIMING AND
AREAL EXTENT OF THE PRECIPITATION THREAT...WILL JUST MENTION A
SLIGHT CHANCE FOR SHOWERS AT THIS TIME AND SEE IF THE MODELS CAN
COME TO SOME KIND OF CONSENSUS.
UPPER LEVEL FEATURE PULLS OUT TO THE EAST THURSDAY AND BRINGS A
RETURN BACK TO FAIR WEATHER THURSDAY AFTERNOON AND NIGHT.
THE BAD NEWS IS THAT CHILLY AIR WILL RETURN BEHIND THE COLD FRONT
DROPPING TEMPERATURES BACK INTO THE 50S FOR HIGHS ACROSS THE
NORTHERN TIER COUNTIES BY WEDNESDAY AND LOWER 60S ACROSS THE SOUTH.
OVERNIGHT LOWS WILL DROP INTO THE 40S. A BIT OF A REBOUND WITH MORE
SUN WILL RETURN ON THURSDAY WITH HIGHS IN THE LOWER TO MIDDLE 60S.
YET LOWS WILL STILL BE IN THE 40S THURSDAY NIGHT. NOT EXPECTING ANY
FROST THROUGH THE PERIOD AT THIS TIME.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
THE LONG TERM BEGINS FRIDAY WITH A COLD FRONT HAVING JUST DROPPED
SOUTH ACROSS THE REGION AND AN UNREASONABLE AMOUNT OF COLD AIR JUST
TO OUR NORTH. DURING THE DAY HIGH PRESSURE WILL BUILD IN FROM THE
WEST AND WHILE TEMPS WILL BE ON THE COOL SIDE...BOTH MODELS TAKE THE
CORE OF THE COLD AIR EAST ACROSS QUEBEC AND NORTHERN NEW ENGLAND.
SATURDAY THE HIGH MOVES EAST AND HEIGHTS BEGIN TO RECOVER AS WARMER
AIR BEGINS TO RETURN TO THE REGION. AN UPPER RIDGE WILL BE MOVING
INTO THE MIDWEST HOWEVER A SURFACE LOW IN THE CENTRAL PLAINS WILL
BEING DEEP MOISTURE INTO THE MID MISSISSIPPI VALLEY UNDER THE
RIDGE. BY SATURDAY NIGHT AND SUNDAY THIS MOISTURE WILL LIKELY BE
SPILLING INTO THE AREA WITH DEEP SOUTHERLY FLOW INTO THE AREA AHEAD
OF A DEVELOPING UPPER TROF IN THE PLAINS. WILL KEEP FORECAST DRY
THROUGH SATURDAY NIGHT BUT BRING MID/HIGH CHANCE POPS IN FOR
SUNDAY. WILL HAVE LIKELY POPS NORTHWEST SUNDAY NIGHT AND MONDAY
WHICH MAY NEED TO BE EXPANDED AS THE FORECAST EVOLVES. TEMPS FRIDAY
FROM THE UPPER 50S NORTHEAST LAKESHORE TO THE LOWER 70S SOUTHWEST.
MOST AREAS WILL SEE LOWER AND MID 70S SATURDAY AND SUNDAY.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
CONDITIONS VFR ACROSS NRN OHIO AND NWRN PA AT 05Z. AIRMASS QUITE
MOIST BUT UPPER RIDGE JUST EAST OF THE AREA MOSTLY KEEPING A LID
ON CONVECTION. GUIDANCE SUGGESTS OVERNIGHT AND INTO THE EARLY
MORNING HOURS CIGS AND VISIBILITIES SHOULD GO DOWN TO IFR IN
STRATUS AND FOG. AM IN AGREEMENT WITH MVFR VISIBILITIES IN A
MORNING FOG/MIST HAVE OPTED TO REMAIN MORE CONSERVATIVE THAN
GUIDANCE WHICH MAY BE TOO PESSIMISTIC AS STRATUS THAT HAS
DEVELOPED HAS BEEN AT 5 TO 7 KFT. TIME WILL TELL. AS FOR MONDAY
GIVEN MOISTURE AND THE APPROACHING COLD FRONT FROM THE WEST WILL
CONTINUE WITH VCTS FOR THE AFTERNOON ACROSS THE AREA IN DIURNAL
CONVECTION. COULD ALSO HAVE ANOTHER LINE APPROACHING WESTERN
TERMINALS TOWARD THE END OF THE PERIOD WITH THE FRONT.
.OUTLOOK...NON VFR AT TIMES IN SCATTERED SHOWERS OR THUNDERSTORMS
TONIGHT. NON-VFR POSSIBLE BEHIND A COLD FRONT IN NE OH/NW PA
TUESDAY AFTERNOON/EVENING.
&&
.MARINE...
LOW PRESSURE OVER LAKE SUPERIOR WILL MOVE NORTHEAST ACROSS ONTARIO
TO QUEBEC TODAY. A COLD FRONT EXTENDING SOUTHWEST FROM THE LOW WILL
CROSS LAKE ERIE TONIGHT. SOUTH TO SOUTHWEST FLOW TODAY AND TONIGHT
WILL REMAIN FAIRLY LIGHT. TUESDAY WINDS WILL INCREASE FROM THE WEST
AND SOUTHWEST TO 15 TO 25 KNOTS/ WINDS WILL TURN NORTHWEST TUESDAY
NIGHT AS THE COLD AIR DEEPENS ACROSS THE LAKE. A LARGE AREA OF HIGH
PRESSURE WILL BUILD TOWARD THE LAKE MID WEEK AS IT DROPS INTO THE
CENTRAL PLAINS. ANOTHER COLD FRONT HOWEVER WILL APPROACH FROM THE
NORTH THURSDAY LIKELY DROPPING ACROSS THE LAKE THURSDAY NIGHT OR
EARLY FRIDAY. NO GALES ARE EXPECTED THROUGH THE PERIOD HOWEVER A
SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED SOMETIME TUESDAY AS WINDS
INCREASE...CONTINUING TUESDAY NIGHT AND MOST OF WEDNESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LOMBARDY
SHORT TERM...LOMBARDY
LONG TERM...TK
AVIATION...TK
MARINE...TK
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
620 AM CDT MON MAY 18 2015
.AVIATION...
VFR CONDITIONS EXPECTED DURING THE DAY...BUT WILL DETERIORATE TO
MVFR DECKS AND VIS COURTESY OF INCREASING CHANCES OF THUNDERSTORMS
THIS EVENING THROUGH TONIGHT. HAVE INSERTING A PREVAILING TSRA AT
ALL THREE TAF SITES...COMMENCING THIS EVENING AT KLBB AND
KPVW...AND MORE SO BY TONIGHT AT KCDS. RAINFALL COULD BECOME HEAVY
AT TIMES. OTHERWISE...LIGHT SOUTHWEST WINDS EARLY THIS MORNING
WILL BACK TO THE SOUTH SOUTHEAST THIS AFTERNOON AT 10-15 KTS.
&&
.PREV DISCUSSION... /ISSUED 340 AM CDT MON MAY 18 2015/
SHORT TERM...
THE SHORT TERM PERIOD WILL FOCUS ON THE RETURN OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS...THAT COULD COMMENCE AS EARLY
AS LATE THIS AFTN.
THE PACIFIC FRONT/DRYLINE THAT AFFECTED THE SOUTHERN PLAINS
YESTERDAY WAS WELL SOUTH AND EAST OF THE CWA EARLY THIS MORNING...AS
HINTED AT BY DEWPOINTS IN THE 60S AND 70S ACROSS THE CONCHO
VALLEY...BIG COUNTRY AND EDWARDS PLATEAU AREAS. AS SUCH...SOME FOG
AND/OR LOW CLOUDS HAVE DEVELOPED ACROSS PORTIONS OF THE SAID AREAS.
COMPUTER MODELS HINT AT THE BOUNDARY RETREATING TO NEAR THE FAR SRN
SOUTH PLAINS AND LOW ROLLING PLAINS BY AOA DAYBREAK...BRINGING WITH
IT RICH LOW LEVEL MOISTURE AND A CHANCE FOR THE FOG AND/OR STRATUS
DECK TO MAKE HEADWAY TOWARDS THE FA. HOWEVER...MODEL SOLUTIONS SUCH
AS THE HRRR AND THE NAM EXHIBIT THE FOG AND LOW CLOUDS TO STOP JUST
SHORT OF THE FA AND DISSIPATE...GIVEN SFC WINDS VEERING TO THE W-SW
THROUGHOUT DAYBREAK AND THUS MITIGATING THE TRANSPORT OF THE LOW
LEVEL MOISTURE. WE WILL CONTINUE TO MONITOR AND SEE IF THIS DOES
INDEED OCCUR.
ATTENTION WILL TURN TO AN UA LOW THAT WAS IMPINGING ON CNTRL/SRN
CALI PER 07Z SATELLITE WATER VAPOR IMAGERY...AND IS PROGGED TO
TRANSLATE ENE TO NEAR THE FOUR-CORNERS REGION BY TONIGHT. AS
SUCH...SW FLOW ALOFT WILL SHARPEN. EMBEDDED WITHIN THIS SW FLOW IS
AN IMPULSE THAT MODEL SOLUTIONS SHOW EJECTING OUT AHEAD OF THE
PARENT UA LOW...AND NEAR THE SWRN ZONES LATE THIS AFTN/EARLY EVENING
AND PROGRESS TO THE NE TO ACROSS THE NERN ZONES BY TONIGHT. WITH SFC
LEE TROUGHING DEEPENING DUE TO THE APPROACHING UA LOW...THIS WILL
AID TO BACK SFC WINDS TO THE S-SE AND PWATS WILL SOAR INTO THE 1.00-
1.50 INCH RANGE BY TONIGHT...WHILST THE LLJ CRANKS UP TO 20-40 KTS.
WITH ALL THAT SAID...CONVECTION IS STILL EXPECTED TO INITIATE ACROSS
THE FAR SW SOUTH PLAINS AS EARLY AS LATE THIS AFTN/EARLY THIS
EVENING...ESPECIALLY IF THE TIMING OF THE ANTICIPATED EMBEDDED
IMPULSE STAYS TRUE. PRECIP WILL BECOME SCATTERED TO PERHAPS
WIDESPREAD AS IT PROGRESSES NE TO ACROSS THE REMAINDER OF THE CWA
THROUGH THE NIGHT. TO ADD FUEL TO THE PROVERBIAL FIRE...A COLD FRONT
WILL BACKDOOR INTO THE REGION THIS EVENING/TONIGHT...WHICH COULD
SERVE AS ANOTHER FOCUS FOR STORM DEVELOPMENT. WITH SUCH HIGH
PWATS...MODERATE-HEAVY RAINFALL CAN NOT BE RULED OUT WHICH RAISES
CONCERNS FOR LOCALIZED FLOODED. WE ALSO NEED TO KEEP AN EYE OUT FOR
SOME STORMS BECOMING STRONG TO SEVERE...ESPECIALLY ACROSS THE SWRN
ZONES LATE THIS AFTN AS PROGGED MUCAPE VALUES OF 2-3 KJ/KG...30-40
KTS OF 0-6 KM BULK SHEAR...STEEPENED LAPSE RATES AND VEERING WIND
PROFILES SAYS AS MUCH /HAIL AND GUSTY WINDS WILL BE THE PRIMARY
THREATS/.
A SEASONABLY WARM DAY WILL PREVAIL WITH HIGHS IN THE 70S AND
80S...FOLLOWED BY OVERNIGHT LOWS IN THE 50S AND 60S.
LONG TERM...
THE WEATHER FOR THE PAST SEVERAL WEEKS /MINUS THE WIND AND LACK
OF 70+ DEGREE DEW POINTS/ HAVE MADE IT FEEL LIKE I AM BACK IN MY
OLD STOMPING GROUNDS IN SOUTH MS...AND IT DOESN/T LOOK LIKE THE
PATTERN WILL CHANGE ANY OVER THE NEXT 7 DAYS AND BEYOND. FOR
STARTERS WPC QPF GUIDANCE PRE 00Z SHOWS UPWARDS OF 5 INCHES OF
RAIN OVER THE NEXT 7 DAYS. TUESDAY MORNING WILL START VERY WET
WITH AN UPPER LEVEL LOW WITH A SLIGHT NEG TILT MOVES OVER NV TOWARDS
THE REGION. MODEL OMEGA FIELDS/SOUNDING PROFILES ALL SHOW LIFT AND
NO SUBSIDENCE BY 7AM THOUGH THEY DO VARY ON THE AMOUNT OF LIFT. THE
GFS HAS THE LEAST AMOUNT OF LIFT WITH THE LEAST AMOUNT OF QPF WHILE
THE NAM/ECMWF ARE FAIRLY IN LINE WITH EACH OTHER. PWAT VALUES WILL
BE RELATIVELY HIGH...1.25 TO 1.5 INCHES ON THE CAPROCK WHILE
APPROACHING 2 INCHES ACROSS THE EASTER ROLLING PLAINS. THIS IS IN
PART DUE TO MOIST SURFACE CONDITIONS AS WELL AS A 40KT LLJ PUMPING
IN MOISTURE FROM THE GOMEX. ONE CONCERN WITH TUESDAY MORNING WILL BE
FLOODING. WITH ALREADY SATURATED SOILS AND FULL PLAYA LAKES RUN
OFF...MAINLY IN URBAN AREAS...WILL BE ALL BUT GUARANTEED WITH A
QUICK 1 INCH RAINFALL CAUSING PROBLEMS. WHILE ACTUAL RAINFALL
AMOUNTS AS WELL AS THE LOCATION OF THE HEAVIEST RAIN IS HARD TO
PINPOINT NEARLY 24 HOURS OUT...THE EXPECTED WIDESPREAD DYNAMIC LIFT
IN ADDITION TO THE RICH MOISTURE TRANSPORT VIA THE LLJ SHOWS THAT
HEAVY RAIN MAY BE FAIRLY WIDESPREAD. GIVEN THAT THIS IS EXPECTED TO
HAPPEN DURING THE MORNING TRAFFIC RUSH AN AREAL FLOOD WATCH MAY BE
WARRANTED. FOR NOW WE WILL DEFER THE WATCH DECISION TO THE NEXT
SHIFT FOR FURTHER EVALUATION OF MORE UP TO DATE INFO. THERE IS A
POSSIBLE SEVERE THREAT LATER TOMORROW AFTERNOON/EVENING DEPENDING ON
HOW MUCH SURFACE HEATING CAN BE ACHIEVED. THIS WILL BE DEPENDENT ON
CLOUD COVER. AS OF NOW OUR WESTERN ZONES HAVE SOMEWHAT HIGHER
CHANCES TO SEE SEVERE STORMS THAN THE REST OF THE FA AS CLOUDS WILL
BEGIN TO THIN FROM WEST TO EAST.
WE SHOULD SEE PRECIP MOVE OFF TO THE EAST BY WED MORNING AS A FRONT
APPROACHES FROM THE NORTH. MODEL TIMING WITH THE FROPA DIFFERS WITH
THE GFS /FRONT PUSHING INTO OUR NORTHERN ZONES BY 00Z THURS/ BEING
SLOWER THAN THE ECMWF /FRONT THRU THE FA BY 00Z/. OTHER THAN A WIND
SHIFT AND CLOUD COVER THIS SHOULDN/T CREATE MUCH OF A HEADACHE AS
FAR AS THE FORECAST IS CONCERNED. THE FROPA WILL BE ACCOMPANIED BY A
LOW STRATUS DECK THAT WILL STICK AROUND FOR MUCH OF WED NIGHT INTO
THURS AFTERNOON. RAIN WILL BE POSSIBLE MAINLY DUE TO ISENTROPIC
LIFTING. THE BIGGEST CHANGE TO THE FORECAST DURING THIS PERIOD IS
MAKING THE PRECIP MAINLY IN THE FORM OF RAIN WITH A MENTION OF ISO
THUNDER AS THE CHANCE EXISTS FOR SOME ELEVATED CAPE. ANOTHER LOW IS
PROGGED TO MOVE INLAND ACROSS SOCAL WHICH WILL RETURN SURFACE FLOW
OUT OF THE SOUTH/SOUTHEAST AND SET UP A DRYLINE OVER CENTRAL NM.
THIS WILL BE OUR NEXT BIG RAIN MAKER AS THE DRYLINE PUSHES EASTWARD
AND THEN RETREATS FRIDAY AND SATURDAY.
TEMPS WILL CONTINUE TO REMAIN BELOW SEASONAL AVERAGE AS CLOUD COVER
WILL BE ABUNDANT THRU THE WEEK AND SURFACE MOISTURE WILL HELP
MODERATE SURFACE TEMPS. THURS WILL BE PARTICULARLY CHILLY WITH TEMPS
AVERAGING 20 DEGREES BELOW SEASONAL AVERAGE /MID 60S/ DUE TO SURFACE
CAA ASSOCIATED WITH THE FROPA. ALDRICH
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 78 55 71 49 / 10 80 90 20
TULIA 79 57 69 51 / 10 80 90 40
PLAINVIEW 79 58 70 53 / 10 80 90 40
LEVELLAND 83 60 74 56 / 20 80 90 30
LUBBOCK 83 61 73 57 / 10 80 90 40
DENVER CITY 82 61 76 60 / 30 80 80 20
BROWNFIELD 84 61 74 59 / 20 80 90 30
CHILDRESS 86 63 71 60 / 10 60 90 60
SPUR 84 63 73 61 / 10 70 90 50
ASPERMONT 87 66 75 64 / 10 70 90 50
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
29
AREA FORECAST DISCUSSION
NWS RENO NV
300 PM PDT MON MAY 18 2015
.SYNOPSIS...
LOW PRESSURE ALOFT WILL REMAIN OVER CALIFORNIA AND NEVADA THROUGH
THE END OF THE WORK WEEK, BRINGING BELOW AVERAGE TEMPERATURES
AND ROUNDS OF SHOWERS AND THUNDERSTORMS, MAINLY IN THE AFTERNOONS
AND EVENINGS. PRECIPITATION CHANCES DECREASE OVER THE MEMORIAL
DAY WEEKEND ALTHOUGH A FEW SHOWERS AND THUNDERSTORMS WILL STILL
BE POSSIBLE.
&&
.SHORT TERM...
A TROUGH OF LOW PRESSURE REMAINS OVER THE WEST. AN UPPER
DISTURBANCE OVER SOUTHEAST CALIFORNIA AND SOUTHERN NEVADA IS
ROTATING AROUND THE TROUGH, BRINGING INCREASED DIVERGENCE ALOFT
AND HELPING TO INITIATE SHOWERS AND THUNDERSTORMS OVER SOUTHERN
AND EASTERN NEVADA.
FOR NORTHEAST CALIFORNIA AND WESTERN NEVADA, ACTIVITY IS RESTRICTED
EARLY THIS AFTERNOON WITH THE BEST FORCING SOUTH AND EAST OF THE
AREA. HOWEVER, SCATTERED SHOWERS SHOULD STILL DEVELOP GIVEN THE
MOIST AND WEAKLY UNSTABLE ATMOSPHERE, ESPECIALLY FOR EASTERN
CALIFORNIA AND FAR WESTERN NEVADA WHERE THE HRRR AND NAM SHOW A
LIGHT WESTERLY FLOW OFF THE SIERRA (TO AID LOW LEVEL CONVERGENCE
AND UPWARD MOTION) INTO THE EVENING. AS FAR AS THUNDERSTORMS, LOW
FREEZING LEVELS AND WEAK INSTABILITY MAKE IT HARD TO RULE OUT
BRIEF, ISOLATED CELLS. ANY STORMS THIS EVENING WILL BE WEAK WITH
THE MAIN THREAT BEING LIGHTNING AND LARGE QUANTITIES OF SMALL,
SOFT HAIL (GRAUPEL TECHNICALLY).
LATE TONIGHT, THE HRRR AND LESS-SO THE GFS AND NAM ARE INDICATING
WRAP-AROUND PRECIPITATION OVER NORTHEAST CALIFORNIA AND NORTHWEST
NEVADA AS THE UPPER LOW ADVANCES INTO EASTERN NEVADA. WITH THIS IN
MIND, I HAVE LEFT IN SCATTERED SHOWERS NORTH OF RENO AND FALLON
WITH ISOLATED COVERAGE ELSEWHERE.
TUESDAY, THE REGION IS BETWEEN UPPER WAVES. HOWEVER, MOISTURE
REMAINS IN PLACE AND BETTER HEATING IS POSSIBLE WITH LITTLE UPPER
FORCING ALLOWING FOR LESS/THINNER CLOUD COVER IN THE MORNING. THIS
SHOULD FACILITATE SCATTERED SHOWERS IN THE AFTERNOON AND EVENING,
WITH A LOW CHANCE FOR THUNDERSTORMS.
WEDNESDAY, THE BEST UPPER FORCING OF THE SHORT TERM IS EXPECTED AS
ANOTHER DISTURBANCE RELOADS THE SOUTHWEST CONUS TROUGH. THE
DISTURBANCE IS EXPECTED TO MOVE FROM SOUTH TO NORTH THROUGH
CALIFORNIA WITH THE BEST FORCING IN THE AFTERNOON AND EVENING.
WITH THIS IN MIND, I HAVE BUMPED POP A BIT MORE OVER MUCH OF FAR
WESTERN NEVADA AND EASTERN CALIFORNIA WITH NUMEROUS SHOWERS EXPECTED
BY AFTERNOON. WITH THE FORCING, I WOULD EXPECTED AT LEAST ISOLATED
THUNDERSTORMS WITH HIGHER COVERAGE POSSIBLE IF WE CAN GET DECENT
MORNING HEATING (CLEARER SKIES). SNYDER
.LONG TERM...THURSDAY THROUGH MONDAY...
BY THURSDAY AN AREA OF LOW PRESSURE WILL AGAIN BE ALONG THE
CENTRAL CALIFORNIA COAST. THIS WILL CONTINUE TO BRING WIDESPREAD
CHANCES OF PRECIPITATION, ISOLATED THUNDERSTORMS, AND BELOW
AVERAGE DAYTIME TEMPERATURES. THURSDAY CURRENTLY LOOKS TO BE THE
WETTEST DAY WITH MOISTURE WRAPPING AROUND THE LOW PRESSURE AND
BANKING AGAINST THE SIERRA FROM THE EAST. RELATIVELY DEEP MOISTURE
AND UPSLOPE FLOW COULD ALLOW SOME AREAS TO PICK UP ANOTHER ROUND
OF SIGNIFICANT PRECIPITATION, ESPECIALLY IN THE CENTRAL SIERRA.
BY FRIDAY THE LOW PRESSURE WILL MOVE INTO SOUTHERN NEVADA
BRINGING NORTHERLY FLOW TO THE AREA. THIS WILL DECREASE THE CHANCE
OF SIGNIFICANT QPF IN THE SIERRA, BUT WILL STILL ALLOW WIDESPREAD
PRECIPITATION TO WESTERN NEVADA AND THE SIERRA.
FOR THE HOLIDAY WEEKEND...
CHANCES FOR THUNDERSTORMS WILL BE ON THE DECREASE BY THE HOLIDAY
WEEKEND AS THE LOW PRESSURE MOVES INTO THE ROCKIES, BUT WITH SOME
RESIDUAL MOISTURE AND INCREASING TEMPERATURES THERE IS STILL A
SLIGHT CHANCE OF THUNDERSTORM ACTIVITY IN SIERRA AND WESTERN
NEVADA THROUGH THE WEEKEND. SIGNIFICANT MODEL DISCREPANCIES EXIST
BY THE WEEKEND SO FORECAST CONFIDENCE IS CURRENTLY LOW ON THE
BEST AREA FOR THUNDERSTORM CHANCES.
EXPECT A WARMING TREND THROUGH THE WEEKEND WITH DAYTIME
TEMPERATURES RIGHT AROUND SEASONAL AVERAGES WITH MID 70`S IN
WESTERN NEVADA AND MID 60`S IN THE SIERRA. BY MONDAY WESTERN
NEVADA VALLEYS COULD HIT 80 WITH SIERRA VALLEYS REACHING 70.
TOLBY
&&
.AVIATION...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED
THROUGHOUT THE SIERRA AND WESTERN NEVADA THROUGH THIS EVENING.
LOW CLOUD DECKS AND RAIN SHOWERS WILL CREATE SOME MOUNTAIN
OBSCURATION IN THE SIERRA. GENERALLY LIGHT WEST WINDS WITH THE
CHANCE OF GUSTS TO AROUND 30 KTS NEAR THUNDERSTORMS. TOLBY
&&
.REV WATCHES/WARNINGS/ADVISORIES...
NV...NONE.
CA...NONE.
&&
$$
FOR MORE INFORMATION FROM THE NATIONAL WEATHER SERVICE VISIT...
HTTP://WEATHER.GOV/RENO (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS TAUNTON MA
318 PM EDT MON MAY 18 2015
.SYNOPSIS...
MARITIME HIGH PRESSURE BUILDS OVER NEW ENGLAND BRINGING COOLER
MARINE AIR TODAY...BUT IT SILL WILL BE A RATHER MILD DAY ACROSS THE
INTERIOR. ANOTHER COLD FRONT WILL BRING SCATTERED SHOWERS
TO THE REGION TONIGHT INTO TUE WITH A LOW POTENTIAL FOR AN
ISOLATED THUNDERSTORM. WIDELY SCATTERED SHOWERS ARE POSSIBLE
WEDNESDAY...FRIDAY...AND MONDAY. BUT IN GENERAL DRY WEATHER AND
SEASONABLE TEMPS ARE EXPECTED FROM MID WEEK THROUGH EARLY NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
200 PM UPDATE...
SKIES HAVE BECOME MOSTLY SUNNY ACROSS THE VAST MAJORITY OF THE
REGION AT MID AFTERNOON. TEMPS HAVE CLIMBED INTO THE 70S ACROSS THE
INTERIOR...60S JUST INLAND FROM THE COAST...AND BETWEEN 55 AND 60
ALONG THE IMMEDIATE COAST.
TEMPS MAY CLIMB ANOTHER FEW DEGREES ESPECIALLY ACROSS THE INTERIOR.
HOWEVER...THE MAIN CONCERN ARE THE LOW CLOUDS AND AREAS OF FOG JUST
MOVING ONTO THE OUTER-CAPE. MOST OF THE GUIDANCE IS NOT HANDLING
THIS WELL...BUT THE HRRR AND TO SOME DEGREE THE RAP SHOWS THESE LOW
CLOUDS AND FOG BACKING INTO EASTERN MAY LATE THIS AFTERNOON/EARLY
THIS EVENING. CONFIDENCE IS LOW...BUT GIVEN EASTERLY FLOW LEANING
TOWARDS THAT HAPPENING. WILL CONTINUE TO MONITOR.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
LOW PRESSURE MOVES INTO QUEBEC BRINGING A COLD FRONT TOWARDS
SOUTHERN NEW ENGLAND. MUCH OF TONIGHT SHOULD BE DRY WITH INCREASING
CLOUDS. SHOWERS SHOULD HOLD OFF UNTIL WELL AFTER MIDNIGHT.
TEMPERATURES OVERNIGHT WILL BE A COUPLE OF DEGREES COOLER THAN THIS
MORNINGS TEMPS WITH THE CONTINUED EASTERLY FLOW AND HIGH PRESSURE
EAST OF SOUTHERN NEW ENGLAND.
SHOWERS WILL BEGIN WELL AFTER MIDNIGHT AS THE FRONT APPROACHES
SOUTHERN NEW ENGLAND. INSTABILITY INCREASES AS DAYBREAK APPROACHES
WITH INCREASING MID LEVEL LAPSE RATES AND K INDICES ABOVE 30.
SHOWALTER INDICES FALL BELOW 0 IN A FEW LOCATIONS BUT THIS IS NOT
WIDESPREAD. WITH THE INSTABILITY IN PLACE...EXPECT WE WILL SEE A
FEW THUNDERSTORMS BUT BELIEVE THE MAIN THREAT WILL BE FROM AREAS OF
HEAVY RAINFALL. PWATS OF 1.5 TO 1.75 INCHES ARE ABOUT 2 STD ABOVE
NORMAL FOR MID MAY. IN ADDITION...850MB WINDS ARE ONLY 20-25KTS.
NOT ENOUGH TO MOVE STORMS ALONG QUICKLY. DON/T BELIEVE THERE WILL
BE WIDESPREAD FLOODING BUT DEPENDING ON THE TRACKS OF STORMS COULD
SEE SOME POOR DRAINAGE FLOODING WHERE STORMS TRAIN.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
BIG PICTURE... THE PATTERN EVOLVES THROUGH THE WEEKEND WITH FLAT
FLOW IN THE EASTERN USA GIVING WAY TO A DIGGING TROUGH LATE WEEK.
THE TROUGH RELAXS A LITTLE OVER THE WEEKEND. TWO SHORTWAVES MOVE
THROUGH THE FLOW...ONE ON WEDNESDAY AND THE SECOND ON FRIDAY.
CONTOUR HEIGHTS LOWER BELOW SEASONAL NORMS WEDNESDAY-THURSDAY...THEN
RETURN TO NEAR SEASONABLE LEVELS OVER THE WEEKEND. JET PATTERN
STARTS WITH NORTHERN AND SOUTHERN STREAMS...BUT THESE MERGE LATER IN
THE WEEK IN THE EASTERN USA AS THE UPPER TROUGH DIGS.
THE DAILIES...
WEDNESDAY... COLD FRONT MOVES WELL OFFSHORE WEDNESDAY WITH COOLER
DRIER AIR MOVING INTO NEW ENGLAND. UPPER SHORTWAVE AND COLDER
TEMPS/MOISTURE ALOFT WILL GENERATE DIURNAL CU ESPECIALLY ALONG AND
NORTH OF THE MASS PIKE. THE AIRMASS IS PROBABLY TOO DRY BELOW 5000
FEET FOR SCATTERED AFTERNOON SHOWERS. MIXING SHOULD REACH 850 MB
WHICH WHERE TEMPS OF 1-4C SHOULD SUPPORT MAX SFC TEMPS IN THE 60S.
TEMPS COULD REACH 70 IN THE SOUTH ESPECIALLY RI/SOUTHEAST MASS WHERE
TEMPS ALOFT MAY BE A LITTLE MILDER OR MIXING A LITTLE DEEPER. WINDS
IN THE MIXED LAYER WILL BE 20-25 KNOTS...SO WIND GUSTS SHOULD
APPROACH THOSE SPEEDS.
WINDS DIMINISH WEDNESDAY NIGHT AS HIGH PRESSURE BUILDS IN. WITH DEW
POINTS IN THE 30S...TEMPS SHOULD FALL TO THE 30S IN THE COLDER
SPOTS...WITH 40S SOUTH AND EAST.
THURSDAY...AFTER THE CHILLY START HIGH PRESSURE SHOULD PROVIDE A
FAIR DRY DAY. MIXING SHOULD REACH 800 MB WHERE TEMPS 0-2C SUPPORT
MAX SFC TEMPS 65 TO 70.
FRIDAY-SATURDAY-SUNDAY... UPPER SHORTWAVE AND CORRESPONDING SURFACE
COLD FRONT SWEEP THROUGH ON FRIDAY. THIS MAY CAUSE WIDELY SCATTERED
SHOWERS BUT PRECIP WATER VALUES AT OR BELOW 0.5 INCHES SUGGEST A DRY
ENVIRONMENT TO OVERCOME. WE USED LOW-END SLIGHT CHANCE POPS FOR THIS
PASSAGE. HIGH PRESSURE THEN BUILDS EAST SATURDAY AND PROVIDES DRY
WEATHER MUCH OF THE WEEKEND.
SUNDAY NIGHT-MONDAY...A COLD FRONT DROPS SOUTH INTO NEW ENGLAND.
MODEL CONSENSUS SUGGESTS A FEW SHOWERS MOVING THROUGH THE REGION
DURING THIS PERIOD...BUT QUESTIONS ABOUT HOW FAR SOUTH THE FRONT
PROGRESSES BEFORE STALLING. WE WILL CONTINUE TO INDICATE A CHANCE OF
SHOWERS.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THIS AFTERNOON THROUGH TUESDAY NIGHT/...
THIS AFTERNOON AND TONIGHT...LOW TO MODERATE CONFIDENCE. VFR
CONDITIONS AT MID AFTERNOON WILL DETERIORATE TO LOW END MVFR/IFR
WITH EVEN SOME LIFR CONDITIONS POSSIBLE TONIGHT...BUT TIMING HIGHLY
UNCERTAIN.
MODELS NOT PICKING UP ON A DECK OF LOW CLOUDS/FOG SITTING OFF CAPE
COD WHICH MAY BACK INTO EASTERN MA LATER THIS AFTERNOON/EVENING.
OTHER AREAS OF LOW CLOUDS AND FOG ARE EXPECTED TO DEVELOP ACROSS THE
REST OF THE REGION...BUT TIMING UNCERTAIN. A CLUSTER OF SHOWERS AND
PERHAPS A FEW EMBEDDED THUNDERSTORMS WILL MAY WORK INTO OUR WESTERN
ZONES TOWARD DAYBREAK.
TUESDAY AND TUESDAY NIGHT...LOW TO MODERATE CONFIDENCE. A CLUSTER
OF SHOWERS AND PERHAPS A FEW EMBEDDED THUNDERSTORMS ARE EXPECTED TO
MOVE ACROSS THE REGION TUE MORNING INTO EARLY AFTERNOON...BEFORE
EXITING THE REGION. LOW END MVFR TO IFR CONDITIONS EXPECTED FOR AT
LEAST THE MORNING. TEMPORARY IMPROVEMENT TO VFR MAY OCCUR
ESPECIALLY ACROSS THE INTERIOR TUE AFTERNOON. A FEW STRONG
THUNDERSTORMS MAY WORK INTO WESTERN MA/NORTHERN CT LATE TUE
AFTERNOON/EVENING. ISOLATED STRONG WIND GUSTS/HAIL WILL BE POSSIBLE
WITH THIS ACTIVITY. EXPECT THE ACTIVITY TO WEAKEN AS IT MOVES INTO
EASTERN MA/RI. CONDITIONS THEN IMPROVE TO VFR FROM WEST TO EAST.
KBOS TERMINAL...LOW CONFIDENCE. WATCHING A BANK OF LOW CLOUDS/FOG
THAT MAY MOVE INTO THE TERMINAL LATE THIS AFTERNOON/EARLY EVENING
BUT LOW CONFIDENCE.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. LOW END MVFR TO IFR
EXPECTED TO DEVELOP TONIGHT BUT TIMING UNCERTAIN.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...MODERATE CONFIDENCE.
VFR THROUGH THE PERIOD. NORTHWEST WINDS WILL GUST TO 25 KNOTS
WEDNESDAY.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH SUNDAY NIGHT/...HIGH CONFIDENCE.
QUIET BOATING WEATHER EXPECTED WITH HIGH PRESSURE
OVER THE WATERS. EASTERLY WINDS 5 TO 10 KTS WILL SHIFT TO THE SOUTH
TONIGHT AND INCREASE TO 10 TO 15 KTS WITH GUSTS TO 20 KTS TUESDAY.
OUTLOOK...WEDNESDAY THROUGH SATURDAY...MODERATE CONFIDENCE.
WEDNESDAY... INCREASING NORTHWEST WINDS DURING THE DAY. THIS MAY
BRING A PERIOD OF GUSTS TO 25 KNOTS DURING THE AFTERNOON. SEAS
SHOULD REMAIN BELOW 5 FEET. WILL MONITOR FOR POTENTIAL SMALL CRAFT
HEADLINES DUE TO AFTERNOON WIND GUSTS.
THURSDAY-FRIDAY... HIGH PRESSURE MOVES OVERHEAD THURSDAY. A WEAK
COLD FRONT PASSES THROUGH ON FRIDAY. WINDS AND SEAS SHOULD REMAIN
BELOW SMALL CRAFT THRESHOLDS.
FRIDAY NIGHT-SATURDAY... NORTHWEST WINDS BEHIND THE COLD FRONT WILL
INCREASE AND BRING GUSTS TO 25 KNOTS ACROSS THE WATERS. THIS MAY
BRIEFLY BRING SEAS UP TO 5 FEET. A SMALL CRAFT ADVISORY MAY BE
NEEDED.
&&
.FIRE WEATHER...
WEDNESDAY...COOLER DRIER AIR MOVES IN. THE FORECAST HAS STAYED CLOSE
TO MODEL CONSENSUS WHICH BRINGS DEW POINTS DOWN INTO THE 30S WITH
RESULTING MINIMUM RELATIVE HUMIDITY PERCENTAGES IN THE 30S. THERE IS
SOME CONCERN THAT THIS DATA IS MISSING THE PRESENCE OF DRIER AIR
AT 5000 FEET/850 MB...WHERE DEW POINTS ARE FORECAST AT 26-30F
DURING THE AFTERNOON. DAYTIME MIXING OF THIS AIRMASS MAY LOWER
SURFACE DEW POINTS INTO THE UPPER 20S AND CREATE MIN RH VALUES OF
27-31 PERCENT. ALONG WITH THIS WILL BE EXPECTED WIND GUSTS NEAR 25
KNOTS. SO THE WEATHER PORTION OF THE FIRE WEATHER EQUATION IS
INCHING TOWARD HIGHER CONCERN AND WILL NEED TO BE MONITORED.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...WTB/RLG
NEAR TERM...FRANK
SHORT TERM...RLG
LONG TERM...WTB
AVIATION...WTB/FRANK
MARINE...WTB/RLG
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS TAUNTON MA
200 PM EDT MON MAY 18 2015
.SYNOPSIS...
MARITIME HIGH PRESSURE BUILDS OVER NEW ENGLAND BRINGING COOLER
MARINE AIR TODAY...BUT IT SILL WILL BE A RATHER MILD DAY ACROSS THE
INTERIOR. ANOTHER COLD FRONT WILL BRING SCATTERED SHOWERS
TO THE REGION TONIGHT INTO TUE WITH A LOW POTENTIAL FOR AN
ISOLATED THUNDERSTORM. DRY WEATHER AND SEASONABLE TEMPS WILL
FOLLOW FOR MID WEEK LASTING THROUGH NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
200 PM UPDATE...
SKIES HAVE BECOME MOSTLY SUNNY ACROSS THE VAST MAJORITY OF THE
REGION AT MID AFTERNOON. TEMPS HAVE CLIMBED INTO THE 70S ACROSS THE
INTERIOR...60S JUST INLAND FROM THE COAST...AND BETWEEN 55 AND 60
ALONG THE IMMEDIATE COAST.
TEMPS MAY CLIMB ANOTHER FEW DEGREES ESPECIALLY ACROSS THE INTERIOR.
HOWEVER...THE MAIN CONCERN ARE THE LOW CLOUDS AND AREAS OF FOG JUST
MOVING ONTO THE OUTER-CAPE. MOST OF THE GUIDANCE IS NOT HANDLING
THIS WELL...BUT THE HRRR AND TO SOME DEGREE THE RAP SHOWS THESE LOW
CLOUDS AND FOG BACKING INTO EASTERN MAY LATE THIS AFTERNOON/EARLY
THIS EVENING. CONFIDENCE IS LOW...BUT GIVEN EASTERLY FLOW LEANING
TOWARDS THAT HAPPENING. WILL CONTINUE TO MONITOR.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
LOW PRESSURE MOVES INTO QUEBEC BRINGING A COLD FRONT TOWARDS
SOUTHERN NEW ENGLAND. MUCH OF TONIGHT SHOULD BE DRY WITH INCREASING
CLOUDS. SHOWERS SHOULD HOLD OFF UNTIL WELL AFTER MIDNIGHT.
TEMPERATURES OVERNIGHT WILL BE A COUPLE OF DEGREES COOLER THAN THIS
MORNINGS TEMPS WITH THE CONTINUED EASTERLY FLOW AND HIGH PRESSURE
EAST OF SOUTHERN NEW ENGLAND.
SHOWERS WILL BEGIN WELL AFTER MIDNIGHT AS THE FRONT APPROACHES
SOUTHERN NEW ENGLAND. INSTABILITY INCREASES AS DAYBREAK APPROACHES
WITH INCREASING MID LEVEL LAPSE RATES AND K INDICES ABOVE 30.
SHOWALTER INDICES FALL BELOW 0 IN A FEW LOCATIONS BUT THIS IS NOT
WIDESPREAD. WITH THE INSTABILITY IN PLACE...EXPECT WE WILL SEE A
FEW THUNDERSTORMS BUT BELIEVE THE MAIN THREAT WILL BE FROM AREAS OF
HEAVY RAINFALL. PWATS OF 1.5 TO 1.75 INCHES ARE ABOUT 2 STD ABOVE
NORMAL FOR MID MAY. IN ADDITION...850MB WINDS ARE ONLY 20-25KTS.
NOT ENOUGH TO MOVE STORMS ALONG QUICKLY. DON/T BELIEVE THERE WILL
BE WIDESPREAD FLOODING BUT DEPENDING ON THE TRACKS OF STORMS COULD
SEE SOME POOR DRAINAGE FLOODING WHERE STORMS TRAIN.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
HIGHLIGHTS...
* SCT SHOWERS AND AN ISOLD TSTM POSSIBLE TUE EVENING
* DRY AND SEASONABLE CONDITIONS MID WEEK INTO NEXT WEEKEND WITH
WARMING TEMPS NEXT SUNDAY
OVERVIEW...
MODELS REMAIN IN GOOD AGREEMENT ON LARGE SCALE FLOW PATTERN WITH
MID LEVEL VORTEX SETTING UP ACROSS SE CANADA MID TO LATE WEEK WITH
BROAD LONGWAVE TROF ACROSS THE GT LAKES AND NEW ENG. A FEW
SHORTWAVES ROTATING THROUGH THE CYCLONIC FLOW WILL BRING A FEW
FRONTS INTO THE REGION BUT MAINLY DRY AND SEASONABLE CONDITIONS AS
POLAR JET WILL KEEP VERY WARM TEMPS SUPPRESSED TO THE SE US. NEXT
WEEKEND...THE TROF BEGINS TO LIFT NE WITH RISING HEIGHTS AS RIDGE
BUILDS OVER SE US. THIS WILL RESULT IN WARMING TEMPS TOWARD THE
END OF THE WEEKEND.
TUESDAY NIGHT...
COLD FRONT WILL BE MOVING INTO W NEW ENG AROUND 00Z WED. AXIS OF
MARGINAL SFC INSTABILITY WITH CAPES AROUND 500 J/KG WILL BE CONFINED
TO W ZONES INVOF THE FRONT SO A FEW THUNDERSTORMS POSSIBLE ALONG THE
BOUNDARY IN THE EVENING IN THE WEST. 0-6KM SHEAR AROUND 40 KT BUT
INSTABILITY WILL BE A LIMITING FACTOR FOR SEVERE WEATHER. LOW PROB
OF A STRONG TSTM IN W NEW ENG IN THE EVENING. OTHERWISE...EXPECT A
FEW SHOWERS REST OF SNE IN THE EVENING UNTIL THE FROPA...THEN
PARTIAL CLEARING OVERNIGHT BEHIND THE FRONT.
WEDNESDAY...
DRY POST-FRONTAL NW FLOW WILL PREVAIL AND IT WILL BE GUSTY AT TIMES
WITH GUSTS 25-30 MPH. MID LEVEL SHORTWAVE WILL BE MOVING TO THE
NORTH WITH MAIN IMPACT BEING SOME DIURNAL CU...ESPECIALLY N ZONES.
HIGHS WILL BE MOSTLY IN THE 60S...WITH A FEW 70 DEGREE READINGS IN
RI/SE MA.
THURSDAY THROUGH SUNDAY...
MODELS BRING A WEAK TROF INTO NEW ENG THU FOLLOWED BY A STRONGER
COLD FRONT LATE FRI/FRI EVENING. MAINLY DRY WEATHER EXPECTED
ALTHOUGH CANT RULE OUT A SHOWER ON FRI WITH THE COLD FRONT.
SEASONABLE TEMPS THU WITH SOME MODERATION FRI AHEAD OF THE FRONT.
STRONG HIGH PRES BUILDS INTO THE REGION SAT WITH SOMEWHAT COOLER
TEMPS...THEN HIGH MOVES S OF NEW ENG SUN WITH RETURN FLOW BRINGING
WARMER TEMPS.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THIS AFTERNOON THROUGH TUESDAY NIGHT/...
THIS AFTERNOON AND TONIGHT...LOW TO MODERATE CONFIDENCE. VFR
CONDITIONS AT MID AFTERNOON WILL DETERIORATE TO LOW END MVFR/IFR
WITH EVEN SOME LIFR CONDITIONS POSSIBLE TONIGHT...BUT TIMING HIGHLY
UNCERTAIN.
MODELS NOT PICKING UP ON A DECK OF LOW CLOUDS/FOG SITTING OFF CAPE
COD WHICH MAY BACK INTO EASTERN MA LATER THIS AFTERNOON/EVENING.
OTHER AREAS OF LOW CLOUDS AND FOG ARE EXPECTED TO DEVELOP ACROSS THE
REST OF THE REGION...BUT TIMING UNCERTAIN. A CLUSTER OF SHOWERS AND
PERHAPS A FEW EMBEDDED THUNDERSTORMS WILL MAY WORK INTO OUR WESTERN
ZONES TOWARD DAYBREAK.
TUESDAY AND TUESDAY NIGHT...LOW TO MODERATE CONFIDENCE. A CLUSTER
OF SHOWERS AND PERHAPS A FEW EMBEDDED THUNDERSTORMS ARE EXPECTED TO
MOVE ACROSS THE REGION TUE MORNING INTO EARLY AFTERNOON...BEFORE
EXITING THE REGION. LOW END MVFR TO IFR CONDITIONS EXPECTED FOR AT
LEAST THE MORNING. TEMPORARY IMPROVEMENT TO VFR MAY OCCUR
ESPECIALLY ACROSS THE INTERIOR TUE AFTERNOON. A FEW STRONG
THUNDERSTORMS MAY WORK INTO WESTERN MA/NORTHERN CT LATE TUE
AFTERNOON/EVENING. ISOLATED STRONG WIND GUSTS/HAIL WILL BE POSSIBLE
WITH THIS ACTIVITY. EXPECT THE ACTIVITY TO WEAKEN AS IT MOVES INTO
EASTERN MA/RI. CONDITIONS THEN IMPROVE TO VFR FROM WEST TO EAST.
KBOS TERMINAL...LOW CONFIDENCE. WATCHING A BANK OF LOW CLOUDS/FOG
THAT MAY MOVE INTO THE TERMINAL LATE THIS AFTERNOON/EARLY EVENING
BUT LOW CONFIDENCE.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF. LOW END MVFR TO IFR
EXPECTED TO DEVELOP TONIGHT BUT TIMING UNCERTAIN.
OUTLOOK...WEDNESDAY THROUGH FRIDAY...
WED THROUGH FRI...HIGH CONFIDENCE. VFR. W/NW GUSTS TO 25 KT ON
WED.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SHORT TERM /THROUGH SUNDAY NIGHT/...HIGH CONFIDENCE.
QUIET BOATING WEATHER EXPECTED WITH HIGH PRESSURE
OVER THE WATERS. EASTERLY WINDS 5 TO 10 KTS WILL SHIFT TO THE SOUTH
TONIGHT AND INCREASE TO 10 TO 15 KTS WITH GUSTS TO 20 KTS TUESDAY.
OUTLOOK...TUESDAY NIGHT THROUGH FRIDAY...HIGH CONFIDENCE.
TUE NIGHT...SW WINDS WITH GUSTS TO 20 KT BECOMING NW AFTER
MIDNIGHT. SCT SHOWERS AND PATCHY FOG MAY REDUCE VSBYS IN THE
EVENING.
WED...W/NW WINDS WITH GUSTS TO 25 KT. MARGINAL SCA CONDITIONS
POSSIBLE.
THU INTO FRI...MAINLY SW WINDS BELOW SCA WITH SEAS BELOW SCA.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
RI...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KJC/RLG
NEAR TERM...FRANK
SHORT TERM...RLG
LONG TERM...KJC
AVIATION...FRANK/KJC
MARINE...KJC/RLG
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
349 PM EDT MON MAY 18 2015
.SYNOPSIS...
19Z WATER VAPOR AND H4 RAP ANALYSIS SHOWS YET ANOTHER IN A SERIES
OF STRONG LONGWAVE TROUGH ABOUT TO PIVOT OUT OF THE SOUTHWESTERN
STATES. THE LAST TROUGH IS JUST NOW BEGINNING TO EXIT THE UPPER
MIDWEST...BUT HERE COMES THE NEXT ONE CROSSING INTO THE INTER-
MOUNTAIN WEST. THANKFULLY FOR OUR LOCAL AREA...THIS INCLEMENT
WEATHER WILL REMAIN WELL TO OUR NORTHWEST...WHILE WE REMAIN UNDER
THE CONTROL OF WEAK RIDGING ALOFT INTO TUESDAY.
AT THE SURFACE...ATLANTIC HIGH PRESSURE IS RIDGING BACK INTO THE
NORTHERN FLORIDA PENINSULA THIS AFTERNOON AND WILL CONTINUE TO
BOTH SETTLE SLOWLY SOUTHWARD AND WEAKEN DURING THE NEXT 12-24
HOURS. THE POSITION OF THE RIDGE IS RESULTING IN A LIGHT EASTERLY
FLOW FOR THE SOUTHERN HALF OF THE AREA...AND A LIGHT AND VARIABLE
FLOW TO THE NORTH OF THE TAMPA BAY AREA. ALTHOUGH EASTERLY FLOW IS
GENERALLY FAVORABLE FOR CONVECTIVE DEVELOPMENT ALONG THE WEST
COAST SEA BREEZE...TODAY IS DIFFERENT FROM PREVIOUS DAYS WITH A
SUBSTANTIAL LAYER OF DRY/HOSTILE AIR TOWARD DEEP CONVECTION IN THE
MID LEVELS. CAN NOT RULE OUT A FEW ISOLATED STORMS THAT WILL BE
ABLE TO SURVIVE THIS DRIER COLUMN TO THE SOUTH OF THE I-4
CORRIDOR...BUT THEY WILL BE FEW AND FAR BETWEEN. MOISTURE PROFILES
ARE SLIGHTLY BETTER OVER OUR FAR NORTHERN AREAS...AND ACTUALLY
STARTING TO SEE SOME STORMS DEVELOP UP TOWARD PERRY/CROSS CITY.
THINK BETTER CHANCES FOR A FEW EVENING STORMS FOR OUR AREA WILL BE
UP TOWARD CITRUS/LEVY/NORTHERN SUMTER COUNTY...AS THE SEA-BREEZE
SLOWLY MIGRATES INLAND.
&&
.SHORT TERM...
SCT EVENING STORMS DECAY QUICKLY WITH THE LOSS OF DIURNAL HEATING
LATER THIS EVENING...SETTING UP A GENERALLY DRY AND SEASONABLY
WARM MID MAY OVERNIGHT. OVERNIGHT LOWS GENERALLY IN THE UPPER 60S
TO LOWER 70S FOR MOST SPOTS...ALTHOUGH NORMALLY WARMER LOCATIONS
SUCH AS SOUTHERN PINELLAS COUNTY AND THE ISLANDS OF CHARLOTTE
HARBOR WILL STAY EVEN WARMER WITH DEVELOPING LAND BREEZE FLOW OFF
THE BAYS.
FOR TUESDAY...UPPER RIDGE IS STILL IN PLACE...BUT WILL BEGIN TO
WEAKEN WITH HEIGHTS SLOWLY DROPPING THROUGH THE DAY. AT THE
SURFACE THE RIDGE AXIS WILL SETTLE DOWN INTO THE CENTRAL OR EVEN
SOUTH-CENTRAL FL PENINSULA. THIS MOTION WILL BE FORCED BY THE SLOW
APPROACH OF A WEAK FRONT FROM THE NORTH. THIS FRONT MAY REACH AS
FAR SOUTH AS THE I-10 CORRIDOR BEFORE TUESDAY IS OVER. THE
SYNOPTIC FLOW SOUTH OF THIS FRONT WILL FINALLY SHIFT TO A MORE
WESTERLY DIRECTION ACROSS A LARGE PORTION OF OUR AREA. THE
WESTERLY FLOW WILL CERTAINLY BE WEAKER DOWN TOWARD FORT
MYERS...BUT SHOULD STILL BE PRESENT. THE WEST FLOW WILL ACT TO
STEADILY PROGRESS THE SEA BREEZE INLAND...ESPECIALLY FOR THE
NATURE COAST. BETTER MOISTURE PROFILES...AND ADDED FOCUS
ASSOCIATED WITH THE APPROACHING SYNOPTIC BOUNDARY SHOULD KEEP THE
BEST CHANCES FOR DIURNAL CONVECTION ALONG AND NORTH OF THE I-4
CORRIDOR. WILL HAVE 40-50% POPS FOR THE NORTHERN HALF OF THE
AREA...AND GENERALLY 20-30% (AT BEST) FURTHER SOUTH. HOWEVER...AS
MENTIONED...AS THE SEA-BREEZE MOVES INLAND...RAIN CHANCES WILL
DECREASE NEAR THE COAST (EVEN FOR THE NATURE COAST) AS THE
AFTERNOON PROGRESSES. BY THE EVENING HOURS...MUCH OF THE STORM
ACTIVITY SHOULD BE WELL INLAND. HIGH TEMPERATURES THURSDAY REACH
THE MIDDLE 80S AT THE BEACHES WITH UPPER 80S TO LOWER 90S ALONG
THE I-75 CORRIDOR AND FURTHER INLAND.
&&
.LONG TERM (WEDNESDAY THROUGH NEXT MONDAY)...
WED-FRI: AN UPPER LOW ROTATES OVER EASTERN CANADA WITH A TROUGH THAT
PIVOTS FROM THE UPPER MID-WEST TO THE EASTERN SEA BOARD...FLATTENING
AND SHIFTING AN UPPER RIDGE OVER THE GULF BACK TO THE WEST. AT THE
SURFACE INITIALLY...HIGH PRESSURE SPRAWLS ACROSS THE NORTHERN PLAINS
AND MID-MISSISSIPPI VALLEY WITH A FRONT THAT ARCS FROM THE SAINT
LAWRENCE VALLEY SOUTH ALONG THE EASTERN U.S. COAST THEN BACK WEST
THROUGH THE GULF COASTAL STATES...AND ATLANTIC HIGH PRESSURE
RIDGES ACROSS SOUTHERN FL INTO THE GULF. WITH TIME...THE HIGH
PRESSURE SAGS SOUTH AS IT BUILDS EAST WITH THE FRONT PUSHING EAST
AND SOUTH...WITH THE SOUTHERN/WESTERN END DROPPING DOWN ALONG THE
GULF COAST AND THROUGH NORTHERN FL. THE ATLANTIC RIDGE MEANDERS
OVER OR OFF SOUTHERN FL.
SAT-MON: A PACIFIC UPPER LOW MOVES ACROSS THE GREAT BASIN AND OUT
OVER THE PLAINS AS AN OPEN WAVE WITH UPPER RIDGING BUILDING BACK OVER
THE GULF THEN SLIDING ACROSS THE SOUTHEAST U.S. TO THE ATLANTIC.
THE SURFACE HIGH...BY NOW OVER THE UPPER MID-WEST AND UPPER GREAT
LAKES...TRACKS ACROSS THE MID-ATLANTIC STATES THEN OFFSHORE. AS IT
DOES IT BRIDGES THE DECAYING FRONT IN THE NORTHERN GULF AND
NORTHERN FL AND BUILDS IN ACROSS FL.
THE CURRENT FORECAST PHILOSOPHY REMAINS VERY SIMILAR TO THE PAST FEW
DAYS. THE ATMOSPHERE CONTINUES WITH AMPLE MOISTURE FOR ISOLATED TO
SCATTERED SHOWERS AND STORMS. A WESTERLY FLOW PATTERN SETS UP WED
AND CONTINUES THROUGH FRI...WITH A FEW MORNING SHOWERS OR STORMS
POSSIBLE ON THE GULF THEN MORE COVERAGE IN THE AFTERNOONS WITH THE
HIGHEST INLAND. FOR THE WEEKEND THE PATTERN GOES BACK TO EAST AND
SOUTHEAST...AS HIGH PRESSURE BUILDS IN FROM THE NORTH...WITH THE
GREATEST SHOWER/STORM COVERAGE IN THE AFTERNOON AND EARLY EVENING ON
THE WEST COAST...A RESULT OF SEA BREEZE CIRCULATIONS. TEMPERATURES
WILL RUN ABOVE NORMAL...ALTHOUGH THERE MAY BE A SLIGHT DIP LATE IN
THE PERIOD.
&&
.AVIATION...
VFR CONDITIONS PREVAILING ACROSS WEST-CENTRAL AND SOUTHWEST
FLORIDA THIS AFTERNOON. JUST A SLIGHT CHANCE FOR AN ISOLATED STORM
FOR ANY OF THE TERMINALS THROUGH 00Z...HOWEVER MOST AREAS WILL
REMAIN DRY. VFR CONDITIONS GENERALLY PREVAIL FOR THE REMAINDER OF
THE OVERNIGHT INTO TUESDAY MORNING. TOWARD THE END OF THE TAF
PERIOD (18Z)...A FEW SHOWERS SHOULD START TO FORM ALONG THE SEA-
BREEZE IN THE VICINITY OF KTPA/KPIE...AND MAY NEED MENTION IN
UPCOMING TAF PACKAGES.
&&
.MARINE...
HIGH PRESSURE THAT HAS BEEN OVER THE EASTERN SEABOARD
SHIFTS SOUTHWARD AS A WEAK FRONTAL SYSTEM APPROACHES FROM THE
NORTH ON TUESDAY. THIS INTERACTION WILL ALLOW FOR THE WINDS TO
SHIFT TO A MORE WEST OR NORTHWEST DIRECTION THROUGH THE MIDDLE OF
THE WEEK. THE WESTERLY FLOW WILL HELP KEEP THE BEST CHANCES FOR
STORMS INLAND THE NEXT SEVERAL DAYS. WINDS AND SEAS REMAIN BELOW
HEADLINE CRITERIA.
&&
.FIRE WEATHER...
NO SIGNIFICANT FIRE WEATHER CONCERNS FOR THE NEXT
FEW DAYS AS RELATIVE HUMIDITY VALUES WILL REMAIN ABOVE CRITICAL
LEVELS. THE THUNDERSTORM PATTERN THE NEXT FEW DAYS WILL FAVOR THE
SEA-BREEZE MOVING INLAND BEYOND THE I-75 CORRIDOR...AND THEREFORE
THE HIGHEST RAIN CHANCES WILL BE AWAY FROM THE COAST AND
PROGRESSING INLAND THROUGH THE AFTERNOON AND EARLY EVENING.
FOG IMPACT...NO SIGNIFICANT FOG IS EXPECTED FOR THE NEXT FEW
DAYS...BUT LATE NIGHT PATCHY GROUND FOG COULD DEVELOP IN AREAS
THAT SEE RAIN DURING THE EVENING HOURS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 75 87 75 89 / 10 30 20 30
FMY 72 89 74 91 / 10 20 20 40
GIF 72 90 73 92 / 10 30 30 50
SRQ 73 86 74 87 / 20 20 20 30
BKV 69 90 70 90 / 10 30 10 30
SPG 76 87 76 88 / 20 20 20 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WEATHER...14/MROCZKA
LONG TERM/DECISION SUPPORT...09/RUDE
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
148 PM EDT MON MAY 18 2015
.SYNOPSIS...
ISSUED AT 135 PM EDT MON MAY 18 2015
A COLD FRONT DROPPING ACROSS THE AREA THIS AFTERNOON WILL BRING A
CHANCE FOR SHOWERS AND ISOLATED THUNDERSTORMS THROUGH EARLY EVENING.
COOLER AND DRIER AIR WILL SETTLE IN FOR THE WEEK. HIGHS THIS
AFTERNOON WILL REACH THE LOWER 80S. LOWS TONIGHT WILL DROP BACK
INTO UPPER 40S TO LOWER 50S. EXPECT MUCH COOLER TEMPERATURES TUESDAY
AND WEDNESDAY...WITH HIGHS IN THE MID 50S TO LOWER 60S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 358 AM EDT MON MAY 18 2015
DRIER MID LEVEL AIR HAS ADVECTED INTO MOST OF THE FORECAST AREA THIS
MORNING. DEEPEST MOISTURE THROUGH THE MORNING HOURS IS EXPECTED TO
RESIDE ACROSS APPROXIMATELY THE SOUTHEAST THIRD OF THE AREA WHERE
SOME UPSWING IN 850-700 HPA MOISTURE TRANSPORT IS EXPECTED OVER THE
NEXT SEVERAL HOURS. 3-6 HOUR RAP PROGS DO INDICATE ABOUT 250-500
J/KG OF INSTABILITY LINGERING ACROSS THESE LOCATIONS EXPERIENCING
STRONGER MOISTURE TRANSPORT THIS MORNING...SO HAVE CONTINUED TO
CONCENTRATE LOW CHANCE POPS ACROSS THE SOUTHEAST THIS MORNING AS
ADDITIONAL WEAK SHORT WAVES TRACK NORTHEAST THROUGH THE OHIO VALLEY
IN ASSOCIATION WITH SOUTHERN STREAM.
ATTENTION FOR THE REMAINDER OF THE DAY WILL CENTER ON EVOLUTION OF
SFC COLD FRONTAL BOUNDARY AND POTENTIAL OF ANY ADDITIONAL SCATTERED
CONVECTION THIS AFTERNOON/EARLY EVENING. INSPECTION OF SHORT TERM
TRENDS SUGGESTS NAM MAY BE JUST A BIT SLOW WITH COLD FRONT ACROSS
THE MID MS RVR VALLEY...AND THE NAM CONTINUES TO BE SOMEWHAT OF A
SLOW OUTLIER THROUGH THE NEXT 24 HOURS WITH THE FRONTAL PROGRESSION.
EVEN WITH A PROGRESSION SOMEWHAT FASTER THAN THE NAM...PREFRONTAL
WARMING SHOULD SUPPORT HIGHS IN THE LOWER 80S FOR MOST LOCATIONS
THIS AFTERNOON. OUTSIDE OF FRONTAL CONVERGENCE...MID/UPPER LEVEL
FORCING IS EXPECTED TO BE QUITE WEAK...ALTHOUGH WATER VAPOR EARLY
THIS MORNING DOES DEPICT SOME INTEGRITY TO AN UPSTREAM WAVE LIFTING
NORTHEAST OUT OF OKLAHOMA/SOUTHEAST MISSOURI. THIS FEATURE SHOULD
RAPIDLY EJECT NORTHEAST...BUT BECOME LESS POTENT AS IT BECOMES MORE
HIGHLY SHEARED ACROSS THE OHIO VALLEY/SOUTHERN GREAT LAKES REGION
LATER THIS AFTERNOON/THIS EVENING.
SOME OF THE NAM AND HIRES OUTPUT DOES INDICATE A NARROW ZONE OF
PREFRONTAL CONFLUENCE WITH SOME SUBSTANTIAL MOISTURE POOLING. HAVE
SOME SUSPICION THE SLOWER NAM OUTLIER MAY BE A BIT AGGRESSIVE IN
TERMS OF THE MAGNITUDE OF THIS MOISTURE POOLING AND HAVE GENERALLY
TRENDED AWAY FROM THE INSTABILITY MAGNITUDES ADVERTISED BY THE NAM
ALONG THIS PREFRONTAL CORRIDOR. HAVE MAINTAINED LOW TO MID CHANCE
TSRA FOR TODAY GIVEN AT LEAST SOME WEAK MID/UPPER FORCING LIFTING
INTO THE AREA WITH AFOREMENTIONED OK/MO VORT...ALTHOUGH OUTSIDE OF
ANY AREAS OF PREFRONTAL MOISTURE POOLING...LOW LEVELS MAY MIX OUT
ENOUGH TO TEMPER INSTABILITY QUITE A BIT BY LATER THIS AFTERNOON. IF
SCATTERED CONVECTION IS ABLE TO DEVELOP THERE MAY BE TWO PRIMARY
CORRIDORS FOR INITIATION...ONE ALONG ANY WEAK PREFRONTAL CONVERGENCE
ZONE...AND THEN ALONG THE ACTUAL FRONTAL BOUNDARY. SEVERE STORMS ARE
NOT EXPECTED IN TRENDING TOWARD NON-NAM GUIDANCE FOR THERMAL
PROFILES...AND ALSO GIVEN MORE OF THE SUBSTANTIAL DEEP LAYER SHEAR
WILL BE POST-FRONTAL.
SOME ISOLATED CONVECTION MAY LINGER INTO THE EVENING ACROSS
SOUTHEAST HALF OF THE AREA...WITH MAIN STORY THROUGH THE REMAINDER
OF THE NIGHT CENTERING ON THE APPROACH OF A MUCH COOLER AND LESS
HUMID AIR MASS. SOME COLD ADVECTION STRATOCU MAY WORK INTO FAR
NORTHERN LOCATIONS OVERNIGHT...BUT OTHERWISE MOST LOCATIONS WILL
EXPERIENCE CLEARING SKIES IN THE EVENING.
&&
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 358 AM EDT MON MAY 18 2015
TRANQUIL WEATHER ANTICIPATED FOR MUCH OF THIS LONG TERM PERIOD.
SPLIT FLOW OVER WESTERN NOAM WITH A HIGHLY AMPLIFIED AND ENDURING
NORTHERN STREAM PATTERN ACROSS CANADA WILL LEAVE THE GREAT LAKES IN
A REGION OF STRONG CONFLUENCE AND GENERAL SUBSIDENCE FOR MOST OF
THIS WEEK. WILL ALSO BE MUCH COOLER BEHIND TODAY`S COLD FRONT WITH
PERSISTENT N/NW FLOW MAINTAINING AN EFFICIENT FEED OF CANADIAN AIR
INTO OUR REGION. EXPECT TEMPS ROUGHLY 10-15 DEGREES BELOW NORMAL
DURING THE MIDWEEK PERIOD. TUESDAY NIGHT WILL BE THE COLDEST PERIOD
WITH NUMEROUS SOURCES OF RAW AND STATISTICAL GUIDANCE SUGGESTING MID
30S IN OUR NORTHERN COUNTIES...WITH LOWER 40S IN OUR SOUTH. SOME
CONCERN FOR PATCHY FROST...ESPECIALLY IN OUR MICHIGAN COUNTIES AWAY
FROM THE LAKE. HOWEVER...HIGH BASED CLOUDS WILL BE INCREASING BY
WEDNESDAY MORNING AND MODELS SHOW ENOUGH OF A SURFACE PRESSURE
GRADIENT TO KEEP WINDS IN THE 5-10 MPH RANGE. GIVEN THESE CONCERNS
AND MARGINAL TEMPS WILL HOLD OFF ON MENTIONING ANY FROST IN THE
FORECAST AT THIS POINT AND CONTINUE TO MONITOR.
ONE WEAK SOUTHERN STREAM WAVE DOES EJECT OUT OF THE FOUR CORNERS AND
ATTEMPT TO PHASE WITH SUBTLE NORTHERN STREAM VORT MAX AS IT CROSSES
OUR AREA LATE WEDNESDAY. DEGREE OF DRY AND STABLE LOWER LEVELS IS
CONCERNING BUT FAVORABLE 300MB JET PLACEMENT AND SOME MODEST
CVA/HEIGHT FALLS COULD GENERATE A FEW LIGHT RAIN SHOWERS. NO MAJOR
QUALMS WITH INHERITED LOW CHANCE POPS BUT DID ADJUST THE TIMING UP A
LITTLE BIT BASED ON LATEST NAM AND ECMWF SOLUTIONS. NEXT CHANCE OF
RAIN THEREAFTER WILL NOT BE UNTIL SUNDAY WHEN SOUTHWEST FLOW FINALLY
RETURNS AHEAD OF NEXT WESTERN CONUS TROUGH EJECTING NORTHEAST. THIS
PATTERN SHIFT WILL ALSO SIGNAL THE RETURN OF WARMER AND MORE HUMID
CONDITIONS FOR AT LEAST THE LATTER HALF OF THE HOLIDAY WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 135 PM EDT MON MAY 18 2015
ABUNDANT CLOUD COVER AND LACK OF SIGNIFICANT INSTABILITY /
BOUNDARY LAYER MOISTURE IS PREVENTING CONVECTIVE DEVELOPMENT OVER
THE AREA. ISOLATED SHOWERS HAVE FORMED SOUTH AND EAST OF THE
FORECAST AREA AND EXPECT THIS TREND TO CONTINUE THROUGH THE EARLY
EVENING. AS OF 17Z THE SURFACE COLD FRONT IS LOCATED OVER THE
SOUTHERN TIP OF LAKE MICHIGAN...CROSSING THE IL/IN BORDER. IN THE
CLOUD FREE AREAS THE CU FIELD HAS EXPANDED IN THE PAST FEW HOURS
AND EXPECT THAT TREND TO CONTINUE THROUGH THE EVENING.
FRONTAL PASSAGE WILL BRING IN DRIER AIR AND EXPECT TO SEE AN
ABRUPT WIND SHIFT WITH THE PASSAGE. ADDITIONALLY ALL MODELS
INDICATE STRONG BOUNDARLY LAYER PRESSURE GRADIENT SO GUSTING WINDS
WILL PERSIST THROUGH MUCH OF THE FORECAST PERIOD. LLWS IS NOT
FORECAST...HOWEVER WITH THE ORIENTATION OF THE TROF/SFC
FRONT...EXPECT TO HAVE A BRIEF AND NARROW CORRIDOR OF TURBULENCE
DURING THE PASSAGE.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 5 PM EDT TUESDAY
FOR LMZ043-046.
&&
$$
SYNOPSIS...LEWIS
SHORT TERM...MARSILI
LONG TERM...AGD
AVIATION...LEWIS
VISIT US AT WWW.WEATHER.GOV/IWX (ALL LOWER CASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.YOUTUBE.COM/NWSNORTHERNINDIANA
AREA FORECAST DISCUSSION
NWS JACKSON KY
126 PM EDT MON MAY 18 2015
.UPDATE...
ISSUED AT 938 AM EDT MON MAY 18 2015
JUST MADE SOME ADJUSTMENTS TO THE FORECAST GRIDS THROUGH THE REST
OF THE MORNING. BASED ON CURRENT RADAR IMAGERY...POPS IN OUR
SOUTHWESTERN AND WESTERN COUNTIES NEEDED TO BE INCREASED. WENT
THROUGH AND INCREASED HOURLY POPS OVER THE NEXT 4 HOURS BY 10 TO
15 PERCENT TO ACCOUNT FOR REAL TIME TRENDS. THIS DID NOT CHANGE
THE WORDING IN THE ZONE FORECAST TEXT PRODUCT SO NO UPDATE TO THAT
WAS NECESSARY. IN SUMMARY...THE POP...POP12...AND WEATHER TYPE
GRIDS HAVE ALL BEEN UPDATED.
UPDATE ISSUED AT 709 AM EDT MON MAY 18 2015
A FEW ISOLATED SHOWERS MAINLY ACROSS THE EAST SHOWING UP THIS
MORNING ON WSR-88D RADAR...WITH MORE SHOWERS SLOWLY MOVING EAST
INTO WESTERN PORTIONS OF THE REGION AS WE GO THROUGH THE MORNING.
STORM COVERAGE WILL CONTINUE TO INCREASE THIS AFTERNOON AHEAD OF A
COLD FRONT ACROSS THE UPPER MIDWEST. UPDATED GRIDS WITH LATEST
OBS AND TRENDS. OTHERWISE NO MAJOR CHANGES NEEDED THIS UPDATE.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 350 AM EDT MON MAY 18 2015
03Z SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING INTO THE UPPER
MISSISSIPPI RIVER VALLEY AND FRONT STRETCHED SOUTH INTO THE
CENTRAL PLAINS. BROAD SURFACE HIGH PRESSURE CONTINUES TO CONTROL
THE SE US. THIS IS KEEPING REGION IN WARM AND MOIST ENVIRONMENT
UNDER BROAD SW FLOW. RADAR THIS MORNING SHOWS AREA OF RAIN SHOWERS
CONTINUES TO SLOWLY WANE THIS MORNING NEAR THE TN BORDER. WHILE
THE ACTIVITY IN THE TN VALLEY CONTINUES TO DIMINISH AND SLOWLY
MOVE NE...THE HRRR CONTINUES TO BRING THAT ACTIVITY ACROSS EASTERN
KY. RIGHT NOW THINKING THE HRRR MAY BE A BIT TOO ROBUST WITH THIS
ACTIVITY...HOWEVER RIGHT NOW KEEP SOME ISOLATED TO SCATTERED
ACTIVITY. OTHERWISE FEEL THAT TODAY WILL BE SIMILAR TO THE PAST
FEW DAYS WITH GENERALLY DIURNALLY DRIVEN THUNDERSTORM ACTIVITY.
THE MESO MODELS SHOW STORM ACTIVITY PICKING UP IN COVERAGE AROUND
17Z. AN UPPER LEVEL LOW WILL CONTINUE TO PROGRESS INTO THE GREAT
LAKES AND FLATTEN OUT THE UPPER LEVEL RIDGING THAT HAS BEEN IN
PLACE THE PAST WEEK. THIS WILL ALLOW A BIT MORE UPPER LEVEL WAVE
ENERGY TO PASS THROUGH THE FLOW AND THERE IS A BIT OF DEEPER OMEGA
SIGNALS SEEN IN THE TIME HEIGHTS AS WE MOVE THROUGH THE DAY. THE
MAIN RISK WILL BE POTENTIAL FOR LOCALLY HEAVY RAINFALL WITH THESE
THUNDERSTORMS GIVEN GENERALLY SKINNY CAPE PROFILES WITH NORMALIZED
CAPE VALUES AROUND 0.15 AND PWATS GETTING IN THE 1.70 INCH RANGE
THIS AFTERNOON.
ONCE WE LOOSE DAYTIME HEATING DO DIMINISH STORMS CHANCES
OVERNIGHT INTO TUESDAY. THE COLD FRONT DOES LAG BEHIND AND
CONTINUES TO WEAKEN...AS CANADIAN HIGH BEGINS TO BUILDS EAST. DID
KEEP SOME ISOLATED CHANCES INTO THE DAY ON TUESDAY...BUT THINK
THIS WILL MAINLY BE POSSIBLE ACROSS THE FAR SE. OTHERWISE DRIER
AIR WILL CONTINUE TO SPREAD EAST AND COLUMN WILL CONTINUE TO DRY
SEEN IN FORECAST SOUNDINGS AND TIME HEIGHTS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 434 AM EDT MON MAY 18 2015
SURFACE HIGH PRESSURE RIDGING SE FROM THE NORTH CENTRAL CONUS
WILL PROVIDE DRY WEATHER AT THE START OF THE PERIOD. A PIECE OF AN
UPPER LOW CURRENTLY OVER CA WILL MAKE ITS WAY EASTWARD ACROSS THE
CONUS AT MIDWEEK...AND AS ANOTHER UPPER LOW DROPS SE TOWARD NEW
ENGLAND...THE TWO WILL COMBINE TO BRING AN AMPLIFYING TROUGH TO
THE EASTERN CONUS. AS THE WEAK UPPER LEVEL SYSTEM MOVES IN FROM
THE WEST...THE ECMWF IS MORE ACTIVE WITH THE SYSTEM...AND IT SHOWS
A WEAKENING SURFACE LOW ASSOCIATED WITH IT. THIS BRINGS LIGHT
PRECIP TO OUR LOCAL AREA IN THE WEDNESDAY NIGHT/THURSDAY TIME
FRAME. THE GFS IS WEAKER WITH THE SYSTEM AND ONLY BRINGS CLOUDS.
HAVE OPTED TO USE A MINIMAL 20 PERCENT POP AT THIS POINT.
ONCE THIS SYSTEM MOVES TO OUR EAST BY THURSDAY NIGHT...MODELS AGREE
ON A SURFACE HIGH PRESSURE SYSTEM BUILDING IN FROM THE NW WITH A
REINFORCING PUSH OF DRY AIR. THIS SHOULD HOLD INTO THE WEEKEND.
LATE IN THE WEEKEND MOISTURE SHOULD BE ON THE INCREASE AGAIN AS
THE HIGH MOVES OFF THE EAST COAST AND LOW PRESSURE DEVELOPS OVER
THE PLAINS...TURNING OUR LOW LEVEL FLOW TO THE SOUTH. HAVE
INCLUDED LOW POPS ON SUNDAY...BUT THE BETTER CHANCE OF PRECIP WILL
BE TO OUR WEST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 126 PM EDT MON MAY 18 2015
THE PRIMARY FORECAST CONCERN IN THE TAFS WILL BE SHOWER AND
THUNDERSTORM ACTIVITY THAT IS CURRENTLY MOVING ACROSS EASTERN
KENTUCKY. THESE SHOWERS AND STORMS ARE EXPECTED TO BECOME MORE
NUMEROUS AS THE AFTERNOON WEARS ON AS A COLD FRONT APPROACHES FROM
THE WEST. THE STRONGER STORMS WILL BE CAPABLE OF PRODUCING LOCALLY
HEAVY RAINFALL AND CLOUD TO GROUND LIGHTNING. VFR CONDITIONS WILL
PREVAIL DURING BREAKS IN THE RAIN. OTHERWISE WE THE TAF SITES
COULD EXPERIENCE MVFR TO IFR CONDITIONS WHEN A STRONG SHOWER OR
ANY THUNDERSTORMS MOVES PAST.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AR
SHORT TERM...DJ
LONG TERM...HAL
AVIATION...AR
AREA FORECAST DISCUSSION
NWS LAKE CHARLES LA
1253 PM CDT MON MAY 18 2015
.AVIATION...A THUNDERSTORM COMPLEX CONTINUES TO PUSH SOUTH THROUGH
THE TERMINAL AREA. AEX HAS ALREADY ENCOUNTERED VLIFR AT TIMES WITH
HEAVY RAIN. ACTIVITY WILL BE TAPERING OFF AS THE MCS PUSHES ON
SOUTH...WILL GO MVFR WITH SOME IFR UNTIL LATER THIS AFTERNOON
BECOMING VFR LATE THIS AFTERNOON. COULD SEE SOME MVFR CIG/VIS WITH
LIGHT FOG TOWARDS DAYBREAK. VFR LATE MORNING.
THE REMAINDER OF THE TERMINALS WILL BE DEALING WITH THE
CONVECTIVE COMPLEX THIS AFTERNOON WITH MVFR AS THE SYSTEM WEAKENS
UNTIL LATE AFTERNOON. IFR CIGS LATE TNITE BECOMING MVFR DURING THE
MORNING ON TUESDAY EXCEPT BPT WHERE IFR CIGS COULD LINGER. MVFR
EXPECTED LATE TNITE AT LFT WITH FOG DOWN TO IFR AT ARA.
SWEENEY
&&
.PREV DISCUSSION... /ISSUED 1004 AM CDT MON MAY 18 2015/
DISCUSSION...
SLOW MOVING MCS ACROSS E TX/C LA WILL BE THE MAIN CONCERN THIS
MORNING...ESPECIALLY FOR FLASH FLOOD POTENTIAL ACROSS THIS REGION.
FOR THIS...ISSUED FLASH FLOOD WATCH FOR TYLER & N JASPER/NEWTON
COUNTIES IN SE TX...AND VERNON/RAPIDES/AVOYELLES PARISHES IN C LA.
HIGH POPS REMAIN FOR THE REST OF THE AFTERNOON FROM THE I-10
CORRIDOR NORTHWARD. FURTHER SOUTH SOUTH OF THE I-10 CORRIDOR...POPS
DROP OFF SIGNIFICANTLY AT THIS TIME...BUT WILL HAVE TO WATCH IF
ANY ADDITIONAL OUTFLOW BOUNDARIES MAY GENERATE PRECIP LATER THIS
EVENING AND OVERNIGHT ACROSS THIS REGION.
DML
PREV DISCUSSION... /ISSUED 701 AM CDT MON MAY 18 2015/
DISCUSSION...
FOR THE 12Z TAF PACKAGE.
AVIATION...
ISOLATED SHOWERS CONTINUING TO DEVELOP AND STREAM NORTH ACROSS
PARTS OF SOUTH AND EAST CENTRAL LOUISIANA...WITH MORE ROBUST
CONVECTION TO THE NORTH ACROSS NORTH LA...AND FARTHER WEST TO THE
NW OF HOUSTON OVER SE TX. CONDITIONS ACROSS THE REGION RANGE FROM
LIFR AT KAEX TO VFR AT KLCH. PRIMARY CHALLENGE IS CONVECTIVE
EVOLUTION TODAY...WITH THE TEMPO AND PREVAILING THUNDER IN THE TAFS
REPRESENTING A BLEND OF THE LATEST HRRR RUNS AND THE ONLINE SPC
4KM WRF...WHICH DEPICT THE ACTIVITY BOTH TO THE NORTH AND WEST
EVENTUALLY WORKING INTO THE AREA EITHER LATER THIS MORNING OR THIS
AFTERNOON. A MIX OF MVFR AND VFR WILL OTHERWISE PREVAIL WITH CU
GENERALLY IN THE 1500 TO 3500 FT RANGE AND SOUTHERLY WINDS NOT AS
STRONG AND/OR GUSTY AS YESTERDAY.
13
PREV DISCUSSION... /ISSUED 459 AM CDT MON MAY 18 2015/
SYNOPSIS...
LATEST UA ANALYSIS AND WV IMAGERY SHOWS A MOIST SWLY FLOW ALOFT
CONTINUING WITH A BROAD TROF OVER THE WRN CONUS AND A RIDGE OVER THE
SE. A PAIR OF LOWS WERE SPINNING WITHIN THE TROF...ONE CROSSING THE
NRN PLAINS AND ANOTHER ENTERING CA. MEANWHILE...A PERTURBATION
OVERRIDING AN OUTFLOW BOUNDARY LEFT BEHIND FROM LAST NIGHTS MCV
WAS PRODUCING AN INCREASE IN SHOWERS AND THUNDERSTORMS ACRS NRN LA
WITH SCT ACTIVITY DEVELOPING DOWN TO OUR NRN TIER OF PARISHES AND
COUNTIES. AT THE SFC...S-SE WINDS AROUND THE WRN PERIPHERY OF HIGH
PRES OFF THE SE ATL COAST CONTINUE TO STREAM GULF MOISTURE OVER
THE REGION.
DISCUSSION...
MAIN FCST CONCERN IN THE NEAR TERM IS RAIN CHCS AND THE POTENTIAL
FOR HEAVY RAINFALL. CONVECTION ACRS NRN LA INTO E TX WILL CONTINUE
TO INCREASE THROUGH THE MORNING AS SLY/SWLY WINDS SPREAD ABUNDANT
MOISTURE OVER THE REGION. LIFT WILL BE AUGMENTED BY DIFFLUENCE
ALOFT AND LOW LVL FORCING ALONG THE REMNANT BOUNDARY ACRS CNTL LA
AND THIS WILL HELP TO FOCUS THE PRECIPITATION ACRS NRN/CNTL LA.
RECENT HRRR AND NAM PROGS INDICATE CONVECTION SHOULD SLOWLY
PROPAGATE SOUTHWARD DURING THE DAY. AT THIS TIME...THE HIGHEST
RAINFALL TOTALS ARE EXPECTED TO REMAIN NORTH OF THE CWA.
HOWEVER...PRECIP WATER VALUES ARE RUNNING BETWEEN 1.8-2.0 INCHES
OVER THE AREA...MORE THAN ADEQUATE TO PRODUCE EFFICIENT RAINFALL
RATES AND LOCALIZED HEAVY RAIN ESPECIALLY ACRS THE NRN TIER OF
ZONES. HAVE HELD OFF ON ISSUANCE OF A FLASH FLOOD WATCH FOR NOW
WITH FLOODING EXPECTED TO BE MOSTLY LOCALIZED IN NATURE...BUT WILL
NEED TO MONITOR TRENDS FOR POSSIBLY ISSUANCE LATER THIS MORNING.
RAIN CHCS WILL DIMINISH DURING THE EVENING WITH THE LOSS OF
DAYTIME HEATING. A WEAK FRONT WILL SAG SOUTH INTO THE AREA
TUESDAY...BECOMING STALLED NW-SE ACRS NERN TX INTO CNTL LA. THE
PERSISTENT MOIST SWLY FLOW ALOFT AND EMBEDDED DISTURBANCES WILL
AGAIN BRING ABOUT SCT CONVECTION ON TUESDAY. ALTHOUGH COVERAGE IS
EXPECTED TO BE SLIGHTLY LESS THAN TODAY...EXPECT THE HIGHEST POPS
WILL BE CONCENTRATED ALONG THE FRONTAL BOUNDARY ACRS CNTL LA.
WEAK FLAT RIDGING WILL BEGIN TO DEVELOP ALOFT BY
MIDWEEK...HELPING TO REDUCE BUT NOT ELIMINATE SHOWER COVERAGE AND
CHANCES ON WEDNESDAY. ANOTHER FRONT IS FCST TO MOVE INTO THE AREA
THURSDAY...BRINGING ANOTHER ROUND OF SCT SHOWERS AND TSTMS. THE
FRONT WILL STALL NEAR THE COAST FRIDAY THEN SLOWLY RETREAT BACK
NORTH OVER THE WEEKEND. THE RIDGE ALOFT WILL KEEP RAIN CHCS CLOSER
TO 20-30 PERCENT FOR FRIDAY AND SATURDAY...WITH POPS EASING BACK
INTO THE SCT RANGE BY SUNDAY AS THE RIDGE GETS SHIFTED BACK TO THE
EAST OVER THE WEEKEND.
THROUGH THE NEXT FEW DAYS...THE THREAT FOR ANY ORGANIZED SVR
STORMS WILL REMAIN WELL WEST OF THE AREA. HOWEVER...A FEW ISLTD
STORMS COULD PULSE TO STRONG OR MARGINALLY SVR LIMITS DURING THE
AFTN WHEN MAX HEATING CONTRIBUTES TO ENHANCED INSTABILITY. THE
PRIMARY THREAT WILL STILL BE HEAVY RAINFALL AND LOCALIZED FLOODING
IN LOW-LYING OR URBAN AREAS.
LITTLE VARIATION IN TEMPERATURE IS EXPECTED THROUGH NEXT WEEKEND
WITH MAIN IMPACTS TO DAILY TEMPS FROM CLOUDS AND SHOWERS. IN
GENERAL...EXPECT LOWS FROM AROUND 70 INTO THE MIDDLE 70S WHICH IS
ABOUT 5-10 DEGREES ABV NORMAL WHILE HIGHS WILL RUN NEAR NORMAL IN
THE MIDDLE 80S.
24
MARINE...
MODT SELY WINDS WERE OCCURRING OVER THE COASTAL WATERS THIS EARLY
MORNING IN RESPONSE TO ELEVATED WINDS ALOFT AND INFLOW INTO
COMPLEX OF STORMS ACRS NRN LA INTO SE TX. SUSTAINED WINDS HAVE
APPROACHED 20 KNOTS AT TIMES. WITH THIS IN MIND...ADDED EXERCISE
CAUTION HEADLINE TO CWF FOR EARLY THIS MORNING. WINDS WILL
DIMINISH DURING THE MORNING.
OTHERWISE...EXPECT A LT TO MODT ONSHORE FLOW CONTINUING THROUGH
THE WEEK AS HIGH PRES REMAINS EAST OF THE REGION. WIDELY SCT
SHOWERS AND TSTMS WILL BE POSSIBLE THROUGH WEDNESDAY AS A SERIES
OF DISTURBANCES CROSSES THE REGION. CONVECTION WILL BECOME MORE
ISLTD TOWARD THE END OF THE WEEK AS WEAK RIDGING BUILDS IN ALOFT.
24
&&
.PRELIMINARY POINT TEMPS/POPS...
AEX 77 68 86 70 / 80 30 40 30
LCH 84 72 86 73 / 40 20 30 20
LFT 84 72 86 72 / 60 20 50 20
BPT 84 75 86 74 / 40 20 20 10
&&
.LCH WATCHES/WARNINGS/ADVISORIES...
LA...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR LAZ027>029.
TX...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR TXZ180-259-260.
GM...NONE.
&&
$$
AVIATION...11
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
401 PM EDT MON MAY 18 2015
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 359 PM EDT MON MAY 18 2015
WV IMAGERY AND RAP ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
NW ONTARIO INTO THE WRN GREAT LAKES WITH THE LOW CIRCULATION CENTER
NEAR CYQT. AT THE SFC...A TROUGH EXTENDED THROUGH NRN LAKE SUPERIOR
FROM LOW PRES E OF LAKE SUPERIOR. WITH THE WRAP-AROUND MOISTURE/PCPN
MOVING EDGING TOWARD THE AREA...RADARS INDICATED DIURNALLY ENHANCED
SCT/NMRS -SHSN/SHRA FROM NE MN INTO NW WI. SOME LIGHT RAIN OR
DRIZZLE HAD ALSO DEVELOPED INTO UPSLOPE FLOW LOCATIONS OF NW UPPER
MI.
TONIGHT...THE COMBINATION OF DEEP MOISTURE SLIDING INTO THE AREA
BEHIND THE MID LEVEL LOW AND CAA DROPPING 850 MB TEMPS INTO THE -8C
TO -11C RANGE WILL SUPPORT SCT/NMRS -SHRA/-SHSN INTO MAINLY THE WEST
HALF OF UPPER MI. THE MOST FAVORABLE UPSLOPE FLOW AND LOW LEVEL CONV
WILL SHIFT TO LOCATIONS OVER THE W FAVORED BY NRLY FLOW AND INTO N
CNTRL UPPER MI LATE. LOW LEVEL THICKNESS AND WET-BULB ZERO HEIGHTS
SUGGEST ANY PCPN WILL CHANGE OVER TO MAINLY SNOW FROM WEST TO EAST
THIS EVENING. ALTHOUGH QPF AMOUNTS TO AROUND A TENTH OF AN INCH ARE
EXPECTED...WITH THE RELATIVELY WARM GROUND...ANY SNOWFALL AMOUNTS
SHOULD REMAIN AROUND A HALF INCH OR LESS...MAINLY ON GRASSY SURFACES.
TUE...AS HIGH PRES BUILDS TOWARD THE AREA WITH INCREASINGLY ACYC
LOW LEVEL FLOW...AND THE DEEPER MOISTURE DEPARTS TO THE EAST...THE
LINGERING SNOW SHOWERS SHOULD GRADUALLY DIMINISH AND END OVER MOST OF
THE CWA BY 18Z. THERE MAY BE SOME LIGHT PCPN LINGERING OVER THE EAST
DURING THE AFTERNOON. CLOUDS WILL ALSO ONLY SLOWLY DISSIPATE FROM
WEST TO EAST DURING THE MID TO LATE AFTERNOON.
OTHERWISE...UNSEASONABLY COLD CONDITIONS ARE EXPECTED WITH HIGHS
ONLY FROM AROUND 40 NORTH TO THE MID AND UPPER 40S SOUTH AND WEST.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 320 PM EDT MON MAY 18 2015
A GENERALLY QUIET LONG TERM PERIOD IS IN STORE FOR THE UPPER GREAT
LAKES REGION. THIS IS DUE TO THE AREA LARGELY BEING BETWEEN AN
UPPER TROUGH OVER EASTERN CANADA AND ANOTHER OVER THE SOUTHWESTERN
CONUS. WHILE THE UPPER GREAT LAKES REGION WILL BE BRUSHED BY A FEW
WAVES ASSOCIATED WITH THESE FEATURES...THE OVERALL FLOW WILL BE OUT
OF THE NORTHWEST OR WEST-NORTHWEST WITH LIMITED MOISTURE.
HIGH PRESSURE BUILDS INTO THE AREA ON TUESDAY NIGHT AND REMAINS
INTO WEDNESDAY. THE DRY AIR ASSOCIATED WITH THE HIGH WILL DIMINISH
ANY LINGERING CLOUDS OVER THE EASTERN CWA QUICKLY DURING THE EARLY
EVENING HOURS. THE CLEARING SKIES AND WEAKENING WINDS WILL LEAD TO
A COLD NIGHT ACROSS THE AREA ON TUESDAY NIGHT. HAVE FOLLOWED THE
LOWER END OF GUIDANCE (WITH PWAT VALUES ONLY AROUND 0.25IN)...WHICH
GIVES VALUES IN THE 20S FOR MOST INTERIOR LOCATIONS. ALTHOUGH OUR
FROST/FREEZE PROGRAM HASN/T STARTED...WOULD EXPECT A WIDESPREAD
FROST (AND A HARD FREEZE FOR THE INTERIOR WEST) ACROSS UPPER
MICHIGAN AND PERSONS WITH SENSITIVE PLANTS WOULD BE WISE TO PREPARE
FOR A SOLID FROST.
A WEAK COLD FRONT DROPS SOUTH FROM ONTARIO WEDNESDAY NIGHT AND WITH
THE LACK OF MOISTURE ONLY SHOWED A PERIOD OF PARTLY CLOUDY SKIES
AS IT MOVES THROUGH. BEHIND THE FRONT...NORTHERLY FLOW OFF LAKE
SUPERIOR WILL KEEP TEMPERATURES COOLER NEAR LAKE SUPERIOR ON
THURSDAY (50S) WHILE AREAS INLAND RISE TO OR JUST ABOVE 60.
FRIDAY/SATURDAY CONTINUE TO LOOK DRY (WITH TEMPERATURES WARMING
TOWARDS NORMAL) AS ANOTHER CANADIAN HIGH PRESSURE MOVES ACROSS THE
AREA.
THE HIGH WILL DEPART SATURDAY NIGHT...AS ENERGY FROM THE
SOUTHWESTERN CONUS TROUGH EJECTS NORTHEAST TOWARDS THE AREA. A
SURFACE LOW DEVELOPING IN THE PLAINS WITH THIS FEATURE WILL MOVE
INTO IOWA BY SUNDAY NIGHT BEFORE SLOWLY SHIFTING EAST THROUGH
SOUTHERN WISCONSIN BY MONDAY NIGHT. AT THIS POINT...EXPECT THE CWA
TO BE ON THE NORTHERN EDGE OF MUCH OF THE FORCING (WARM FRONT
STALLS OVER SOUTHERN WISCONSIN) AND BEST CHANCES FOR RAIN WILL BE
OVER THE SOUTHERN HALF OF THE CWA AS WEAK SHORTWAVES LIFT NORTHEAST
ACROSS THE AREA IN THE SOUTHWESTERLY FLOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 128 PM EDT MON MAY 18 2015
WRAPAROUND MOISTURE INTO THE WRN TAF SITES WILL PRODUCE SOME SCT
RAIN SHOWERS THIS AFTERNOON AT IWD AND CMX UNDER MVFR CONDITIONS.
EXPECT CIGS NEAR OF JUST ABOVE THRESHOLD AT SAW UNTIL THIS EVENING
WHEN THE COLDER AIR AND GREATER LOW LEVEL MOISTURE MOVE IN. THE PUSH
OF COLDER AIR BEHIND SECONDARY COLD FRONT WILL CHANGE RAIN SHOWERS
AT KIWD AND KCMX OVER TO SNOW SHOWERS THIS EVENING WITH IFR
CONDITIONS DEVELOPING. SCT -SHRA DEVELOPING AT KSAW EARLY EVENING
WILL ALSO CHANGE OVER TO -SHSN LATE TONIGHT WITH CONDITIONS NEAR
IFR. LOW LEVEL MOISTURE WITH NNW WINDS WILL MAINTAIN MVFR CIGS
INTO EARLY TUE AFTERNOON.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 359 PM EDT MON MAY 18 2015
LOW PRES EAST OF LAKE SUPERIOR WILL CONTINUE TO MOVE TO THE EAST
TONIGHT. A TIGHTENING PRES GRADIENT AHEAD OF HIGH PRES BUILDING
TOWARD THE AREA FROM THE NRN PLAINS WILL BOOST NNW WINDS TO 20 TO 30
KNOTS WITH THE POTENTIAL FOR A FEW GALE FORCE GUSTS OVER THE E HALF
LATE TONIGHT AND TUE MORNING. WINDS WILL DIMINISH W TO E TUE
AFTERNOON/NIGHT THE HIGH BUILDS IN FM THE WEST. WED THRROUGH
SAT...WINDS WILL BE UNDER 20KT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
320 PM EDT MON MAY 18 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 508 AM EDT MON MAY 18 2015
WATER VAPOR LOOP AND RAP ANALYSIS SHOWS MID-LVL LOW ROTATING OVER
NRN MN WITH A DRY SLOT AHEAD OF LOW REACHING ACROSS MUCH OF THE
UPPER MI. COLD FRONT MOVING ACROSS MUCH OF THE AREA OVERNIGHT HAS
ALLOWED DRIER AIR TO ADVECT IN FROM THE SW WHICH HAS DISSIPATED THE
DENSE FOG OVER LAKE MI AND AREAS DOWNSTREAM OVER ERN UPPER MI. DRY
SLOT HAS LEFT UPPER MI GENERALLY PCPN FREE OVER THE EARLY MORNING
HRS.
TODAY AND TONIGHT...THE FOCUS TODAY WILL ON COLD SURGE WHICH WILL BE
MOVING INTO THE WEST MID-LATE MORNING AND CONTINUE EASTWARD THROUGH
THE DAY. AHEAD OF THE FRONT OVER THE EAST HALF OF UPPER MI AND AWAY
FROM THE MODERATING INFLUENCE OF LAKE MICHIGAN...SHOULD SEE
TEMPERATURES REACH IN THE MID TO UPPER 60S (WITH A FEW 70S POSSIBLE
IF THERE ARE BREAKS IN THE LOW CLOUDS). OVER THE WEST HALF WHERE
FRONTAL PASSAGE WILL OCCUR EARLIER...MORNING TO EARLY AFTERNOON HIGH
TEMPS WILL RANGE FROM UPPER 40S/50F NEAR IRONWOOD TO LOWER 60S ALONG
A LINE FM MQT TO MENOMINEE. IN ADDITION...ALL OF THE HIGHER
RESOLUTION MODELS ARE SURGING IN A LAKE BREEZE OFF LAKE SUPERIOR
(FROM MARQUETTE EASTWARD) WHICH WILL LEAD TO COOLER NORTHERLY FLOW
BY MID-LATE AFTERNOON OVER NCNTRL AREAS. WITH THE COLD AIR AND
ABUNDANT MOISTURE SURGING INTO THE AREA AS WINDS TURN
WESTERLY...EXPECT ISOLATED TO SCATTERED SHOWERS TO DEVELOP OVER THE
WEST FIRST (ESPECIALLY IN THE FAVORED UPSLOPE AREAS) AND THEN SPREAD
INTO THE CENTRAL AREAS EVENING AND POSSIBLY EASTERN COUNTIES LATE
EVENING/OVERNIGHT. CAA ON BLUSTERY NW TO N WINDS WILL ALLOW 8H TEMPS
TO FALL TO -8 TO -10C OVER MUCH OF THE WEST HALF OF UPPER MI BY 12Z
TUE. 8H TEMPS WILL FALL TO AROUND -5C OVER THE EAST HALF OVERNIGHT.
BEST FORCING OUT AHEAD ANOTHER SHORTWAVE TRACKING ALONG THE
MN/ONTARIO BORDER TONIGHT WILL STAY MAINLY NW OF UPPER MI KEEPING
MUCH OF THE ASSOCIATED LIGHT PCPN N OF UPPER MI. HOWEVER...DEEP
CYCLONIC FLOW/MOISTURE WILL STILL SUPPORT SOME LIGHT PCPN IN UPPER
MI AS WELL...ESPECIALLY IN THE UPSLOPE AREAS OF THE W AND N. WITH
COLD ADVECTION TAKING PLACE AS NOTED BEFORE...THE -SHRA WILL MIX
WITH OR CHANGE TO -SHSN TONIGHT FROM WEST TO EAST. DUE TO THE COLD
ADVECTION AND PCPN OCCURRING DURING THE OVERNIGHT HOURS...CAN`T RULE
OUT A DUSTING TO LOCALLY A HALFINCH OF SNOW ON GRASSY SFCS BY 12Z
TUE.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 320 PM EDT MON MAY 18 2015
A GENERALLY QUIET LONG TERM PERIOD IS IN STORE FOR THE UPPER GREAT
LAKES REGION. THIS IS DUE TO THE AREA LARGELY BEING BETWEEN AN
UPPER TROUGH OVER EASTERN CANADA AND ANOTHER OVER THE SOUTHWESTERN
CONUS. WHILE THE UPPER GREAT LAKES REGION WILL BE BRUSHED BY A FEW
WAVES ASSOCIATED WITH THESE FEATURES...THE OVERALL FLOW WILL BE OUT
OF THE NORTHWEST OR WEST-NORTHWEST WITH LIMITED MOISTURE.
HIGH PRESSURE BUILDS INTO THE AREA ON TUESDAY NIGHT AND REMAINS
INTO WEDNESDAY. THE DRY AIR ASSOCIATED WITH THE HIGH WILL DIMINISH
ANY LINGERING CLOUDS OVER THE EASTERN CWA QUICKLY DURING THE EARLY
EVENING HOURS. THE CLEARING SKIES AND WEAKENING WINDS WILL LEAD TO
A COLD NIGHT ACROSS THE AREA ON TUESDAY NIGHT. HAVE FOLLOWED THE
LOWER END OF GUIDANCE (WITH PWAT VALUES ONLY AROUND 0.25IN)...WHICH
GIVES VALUES IN THE 20S FOR MOST INTERIOR LOCATIONS. ALTHOUGH OUR
FROST/FREEZE PROGRAM HASN/T STARTED...WOULD EXPECT A WIDESPREAD
FROST (AND A HARD FREEZE FOR THE INTERIOR WEST) ACROSS UPPER
MICHIGAN AND PERSONS WITH SENSITIVE PLANTS WOULD BE WISE TO PREPARE
FOR A SOLID FROST.
A WEAK COLD FRONT DROPS SOUTH FROM ONTARIO WEDNESDAY NIGHT AND WITH
THE LACK OF MOISTURE ONLY SHOWED A PERIOD OF PARTLY CLOUDY SKIES
AS IT MOVES THROUGH. BEHIND THE FRONT...NORTHERLY FLOW OFF LAKE
SUPERIOR WILL KEEP TEMPERATURES COOLER NEAR LAKE SUPERIOR ON
THURSDAY (50S) WHILE AREAS INLAND RISE TO OR JUST ABOVE 60.
FRIDAY/SATURDAY CONTINUE TO LOOK DRY (WITH TEMPERATURES WARMING
TOWARDS NORMAL) AS ANOTHER CANADIAN HIGH PRESSURE MOVES ACROSS THE
AREA.
THE HIGH WILL DEPART SATURDAY NIGHT...AS ENERGY FROM THE
SOUTHWESTERN CONUS TROUGH EJECTS NORTHEAST TOWARDS THE AREA. A
SURFACE LOW DEVELOPING IN THE PLAINS WITH THIS FEATURE WILL MOVE
INTO IOWA BY SUNDAY NIGHT BEFORE SLOWLY SHIFTING EAST THROUGH
SOUTHERN WISCONSIN BY MONDAY NIGHT. AT THIS POINT...EXPECT THE CWA
TO BE ON THE NORTHERN EDGE OF MUCH OF THE FORCING (WARM FRONT
STALLS OVER SOUTHERN WISCONSIN) AND BEST CHANCES FOR RAIN WILL BE
OVER THE SOUTHERN HALF OF THE CWA AS WEAK SHORTWAVES LIFT NORTHEAST
ACROSS THE AREA IN THE SOUTHWESTERLY FLOW.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 128 PM EDT MON MAY 18 2015
WRAPAROUND MOISTURE INTO THE WRN TAF SITES WILL PRODUCE SOME SCT
RAIN SHOWERS THIS AFTERNOON AT IWD AND CMX UNDER MVFR CONDITIONS.
EXPECT CIGS NEAR OF JUST ABOVE THRESHOLD AT SAW UNTIL THIS EVENING
WHEN THE COLDER AIR AND GREATER LOW LEVEL MOISTURE MOVE IN. THE PUSH
OF COLDER AIR BEHIND SECONDARY COLD FRONT WILL CHANGE RAIN SHOWERS
AT KIWD AND KCMX OVER TO SNOW SHOWERS THIS EVENING WITH IFR
CONDITIONS DEVELOPING. SCT -SHRA DEVELOPING AT KSAW EARLY EVENING
WILL ALSO CHANGE OVER TO -SHSN LATE TONIGHT WITH CONDITIONS NEAR
IFR. LOW LEVEL MOISTURE WITH NNW WINDS WILL MAINTAIN MVFR CIGS
INTO EARLY TUE AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EDT MON MAY 18 2015
LOW PRES OVER NRN MN WILL MOVE ACROSS LAKE SUPERIOR TODAY INTO THIS
EVENING. AS A RESULT...WINDS ON LAKE SUPERIOR WILL VEER FM SW THIS
MORNING TO NNW LATE TODAY AND TONIGHT AND RAMP UP TO 20 TO 30 KTS
TONIGHT AND TUE...STRONGEST OVER THE EAST HALF. NOT OUT OF THE
QUESTION THAT THERE COULD BE SOME GALE FORCE GUSTS OVER THE E HALF
OF THE LAKE LATE TONIGHT/TUE MORNING. WINDS WILL DIMINISH W TO E TUE
AFTN/NIGHT AS A HIGH PRES RIDGE BUILDS IN FM THE WEST. WED THRU
FRI...WINDS WILL BE UNDER 20KT. LINGERING WARM MOIST AIR WILL ALLOW
FOG TO CONTINUE OVER THE LAKE TODAY...POSSIBLE LOCALLY DENSE OVER
THE EAST HALF THIS MORNING. ALL FOG SHOULD DISSIPATE BY THIS EVENING
AS COLDER AIR ARRIVES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
156 PM EDT MON MAY 18 2015
.UPDATE...
ISSUED AT 156 PM EDT MON MAY 18 2015
SCT SHRA HAVE DEVELOPED OVER THE PAST HOUR...A LITTLE FURTHER
INLAND THAN EXPECTED (FROM W BRANCH TO NEAR BLACK RIVER).
FORECAST ADJUSTED ACCORDINGLY...EXPANDING AND BOOSTING POPS.
FORECAST ALSO ADJUSTED EARLIER TO BOOST MAX TEMPS IN PARTS OF NE
LOWER...ESPECIALLY NEAR APN/ROGERS...PER OBS.
UPDATE ISSUED AT 947 AM EDT MON MAY 18 2015
A STRONG COLD FRONT IS OVER EASTERN WI THIS MORNING. TEMPS ARE
PUSHING 70F ALONG THE WI LAKE MI COAST...BUT ARE IN THE LOW 40S IN
THE NW CORNER OF THE STATE. THERE IS NO PRECIP ALONG THE
FRONT...IN FACT THERE IS NO CLOUD COVER ALONG THE FRONT...THOUGH
POST-FRONTAL CLOUD COVER IS SUBSTANTIAL. CLOSER TO HOME...PATCHY
MID/HIGH CLOUDS ARE SEEN OVER NORTHERN MI...A BIT THICKER ACROSS
EASTERN UPPER.
A COUPLE OF POINTS OF CONCERN TODAY. THE COLD FRONT WILL CROSS THE
REGION THIS AFTERNOON. ANY POTENTIAL CONVECTION ALONG IT LOOKS TO
BE CONFINED TO THE EXTREME SE...AS A GENERAL LACK OF FORCING AND
WARM TEMPS ALOFT WILL PROVE A SIGNIFICANT OBSTACLE. WE MIGHT BE
ABLE TO MUSTER 500J/KG OF SBCAPE IN FAR SE SECTIONS. THE MOST
RECENT HRRR AND RUC RUNS DO TRY TO POP SOMETHING EARLY THIS
AFTERNOON...BEFORE DRIER AIR ARRIVES LATER IN THE DAY. HAVE ADDED
A SLIGHT CHANCE OF A SHRA EARLY/MID AFTERNOON FROM OSC TO
STANDISH.
THE OTHER ISSUE IS ANY POTENTIAL FIRE WX CONCERNS. JUST BEHIND A COLD
FRONT IS A CLASSIC SUMMER FIRE WX PATTERN FOR US...AS WITH STRONG
HEATING WE TEND TO DRY OUT FASTER THAN WE COOL OFF. HOWEVER...
IDEALLY COLD FROPA WOULD HAPPEN A FEW HOURS EARLIER...IN THE
MORNING AS OPPOSED TO THE PM. HAVE LOWERED DEW POINTS A BIT DURING
THE AFTERNOON...BUT HAVE ALSO DONE THE SAME TO LATE-DAY TEMPS AS
THE COOLER AIR MAKES INITIAL INROADS. SO DON/T HAVE RH LEVELS
GOING BELOW 35 PERCENT OR SO.
&&
.NEAR TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 319 AM EDT MON MAY 18 2015
ALL REMAINING SHOWERS HAVE EXITED NE OUT OF OUR CWA EARLY THIS
MORNING...WITH NO ADDITIONAL SHOWER ACTIVITY CURRENTLY PRESENT
UPSTREAM AS THE WRN GREAT LAKES REMAINS FIRMLY WITHIN THE DRY SLOT
ASSOCIATED WITH DEEP LOW PRESSURE NOW CENTERED OVER NRN MINNESOTA.
SKIES HAVE AT LEAST PARTIALLY CLEARED IN RESPONSE TO THIS DRIER AIR
WORKING ITS WAY INTO MICHIGAN. OUR CWA WILL REMAIN WITHIN THE DRY
SLOT THRU MUCH OF TODAY AS THE SURFACE LOW CENTER MAKES SLOW
EASTWARD PROGRESS THRU UPPER MICHIGAN AND INTO QUEBEC BY 00Z
TUESDAY. EXPECT A PARTLY TO MOSTLY SUNNY AND DRY DAY ALONG WITH
UNSEASONABLY WARM TEMPS FOR MOST OF OUR CWA. AFTERNOON HIGHS WILL
ONLY REACH TO AROUND 70 DEGREES ACROSS ERN UPR MICHIGAN WHERE CAA ON
THE BACKSIDE OF THE LOW WILL INITIALLY BEGIN THIS AFTERNOON. BUT
TEMPS WILL ONCE AGAIN WARM INTO THE UPPER 70S AND LOWER 80S FOR NRN
LWR MICHIGAN (COOLER NEAR THE LAKES)...GIVING US ONE LAST DAY OF
SUMMER WARMTH BEFORE THE REALITY OF NRN MICHIGAN IN MID MAY KICKS
BACK IN ON TUESDAY.
LOW LEVEL MOISTURE/CLOUDS WILL WRAP BACK INTO NRN MICHIGAN TONIGHT
ON THE BACKSIDE OF THE DEPARTING LOW. THE CAA BEHIND THE LOW WILL BE
RAPID AND IMPRESSIVE THRU THE NIGHT...AS 850 MB TEMPS DROP FROM +13C
THIS AFTERNOON TO AROUND -2C BY 12Z TUESDAY. AT THIS POINT...THINK
THE ONLY LOCATION THAT WILL SEE A CHANCE OF SHOWERS WILL BE NW
CHIPPEWA COUNTY THIS AFTERNOON AND TONIGHT WHERE CAA AND LOW LEVEL
WRAP AROUND MOISTURE ADVECTION TAKE PLACE SOONEST. THE REST OF OUR
CWA SHOULD BE GENERALLY DRY...BUT WITH DEEP CYCLONIC FLOW...
INCREASING LOW LEVEL MOISTURE AND EVENTUALLY SOME OVER-LAKE
INSTABILITY DEVELOPING LATE TONIGHT THANKS TO CAA...WILL NEED TO
KEEP AN EYE ON THE POTENTIAL FOR SOME SHOWER ACTIVITY TO DEVELOP.
FOR NOW...WILL MAINTAIN A DRY FORECAST WITH INCREASING CLOUDS
TONIGHT. TEMPS WILL BE NOTICEABLY COLDER TONIGHT...WITH LOWS FALLING
MAINLY INTO THE 40S.
&&
.SHORT TERM...(TUESDAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 319 AM EDT MON MAY 18 2015
HIGH IMPACT WEATHER: TUESDAY NIGHT LOW TEMPERATURES/FROST POTENTIAL
FOR N LOWER.
FORECAST CHALLENGE: HOW FAR WILL THE TEMPERATURES FALL TUESDAY
NIGHT.
(05/19)TUESDAY...WITH THE FRONT SEVERAL HUNDRED MILES TO THE EAST,
THE COLD AIR WILL BE PUSHING INTO THE REGION THROUGH THE DAY.
TEMPERATURES WILL PRETTY MUCH GO NO WHERE AS THE 850 MB TEMPERATURES
FALL FROM AROUND 0C TO ABOUT -4 OR -6C DEPENDING ON THE MODEL. THE
ECMWF IS BEGINNING TO BACK OFF ON THE -8C AIR THAT IT WAS
ADVERTISING THE LAST 2 RUNS, WITH IT AROUND -6C AT ANJ. WHILE THE
GFS WILL BE AROUND -4C. WILL HAVE A MIX OF RAIN AND SNOW IN THE
AFTERNOON AS THE SFC TEMPERATURES BEGIN TO FALL INTO THE UPPER 30S
BY IN E UPPER. THE MOISTURE DOESN`T LOOK DEEP ENOUGH FOR
PRECIPITATION IN N LOWER SO WILL LEAVE IT OUT OF THERE, JUST MOSTLY
CLOUDY. OVERNIGHT, THE RH AT 850 MB AND IN THE 700-500 MB LAYER WILL
DROP TO LESS THAN 20% ON BOTH MODELS BY 12Z. AND WITH THE 850 MB
TEMPERATURES MAINTAINING AROUND 0C OR BELOW, AND, AT LEAST ON THE
ECMWF, THE WINDS WILL PROBABLY DECOUPLE, FROST IS PROBABLE, AND
MAYBE A FREEZE IS POSSIBLE. FOR NOW WILL HAVE PATCHY AND AREAS OF
FROST, BUT THIS IS LOOKING MORE WIDE SPREAD IF THE WINDS DROP OFF
LIKE THE ECMWF WOULD SUGGEST.
(05/20)WEDNESDAY...LOOKS TO BE A SUNNY TO PARTLY CLOUDY DAY WITH LOW
RELATIVE HUMIDITY AND HIGH TEMPERATURES, BELOW NORMAL (LOOKS LIKE
NOW AROUND 5 TO 10 DEGREES BELOW) IF THE MODELS PAN OUT. OVERNIGHT,
A 500 MB SHORTWAVE PUSHES THROUGH THE FORECAST AREA, BUT THE MODELS
SUGGEST THAT ONLY THE MOISTURE IN THE 700-500 MB LAYER WOULD
INCREASE, IF ANY AT ALL. SO WILL EXPECT THAT THE NIGHT WOULD REMAIN
DRY. MAY IDEAS IS THAT THE SKY REMAINS CLEAR TO PARTLY CLOUDY, SO
TEMPERATURES LOOK TO BE IN THE LOWER TO MID 30S, SO ANOTHER FROST
NIGHT? PUT PATCHY IN FOR THE INLAND AREAS, AND LEFT THE LAKE SHORES
FROST FREE WHERE THE AIR TEMPERATURE IS EXPECTED TO BE A LITTLE
WARMER.
&&
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 319 AM EDT MON MAY 18 2015
EXTENDED (THURSDAY THROUGH SUNDAY)...WITH THE 500 MB TROUGH THAT
PARKS ITSELF OVER THE NEW ENGLAND STARTING TUESDAY AND HANGS THERE
THROUGH FRIDAY. FRIDAY, THE LOW BEGINS TO MOVE OUT ALLOWING THE 500
MB RIDGE TO BUILD IN THE UPPER GREAT LAKES. SO WHAT DOES THIS MEAN
FOR THE LONG TERM? SFC HIGH PRESSURE WILL CAMP OUT IN THE UPPER
GREAT LAKES THROUGH THE WEEK, KEEPING THE AREA DRY THROUGH SATURDAY
NIGHT, AND THE 500 MB PATTERN WILL KEEP THE HIGH TEMPERATURES AROUND
OR BELOW NORMAL THROUGH THE WEEK WHEN THE NORMAL HIGH TEMPERATURES
IN GAYLORD AND SAULT STE. MARIE ARE IN THE UPPER 60S. SUNDAY, THE
MODELS BEGIN TO KEY IN ON THE NEXT 500 MB LOW THAT MOVES OUT OF THE
CENTRAL ROCKIES AND INTO THE CENTRAL PLAINS, PRODUCING SHOWERS AND
POSSIBLY THUNDERSTORMS AS THE WARM FRONT PUSHES UP THROUGH THE
STATE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 126 PM EDT MON MAY 18 2015
VFR THRU THIS EVENING. MVFR CIGS DEVELOPING OVERNIGHT PLN/TVC/MBL.
LOW PRESSURE IS CENTERED JUST NE OF LAKE SUPERIOR...AND WILL MOVE
QUICKLY INTO QUEBEC THRU THIS EVENING. STRONG COLD FRONT WILL
CROSS NORTHERN MI THIS AFTERNOON/EARLY EVENING. MINIMAL RISK OF
PRECIP WITH THE FRONT...BUT LOW LEVEL MOISTURE WILL INCREASE IN
THE MUCH COLDER AIR BEHIND THE FRONT. MVFR CIGS WILL BECOME
ESTABLISHED AT PLN/TVC/MBL LATE TONIGHT...AND CONTINUE INTO TUE
MORNING. APN WILL STAY VFR.
SW WINDS WILL BE GUSTY (20-25KT) THIS AFTERNOON. WINDS VEER W AND
NW TONIGHT...BECOMING LESS GUSTY FOR A PERIOD...BEFORE
BLUSTERINESS RETURNS TUE MORNING.
&&
.MARINE...
ISSUED AT 319 AM EDT MON MAY 18 2015
WINDS AND WAVES WILL APPROACH SCA CRITERIA TODAY AND ESPECIALLY
TONIGHT AS CAA DEVELOPS ON THE WAKE OF A DEPARTING LOW. AT THIS
POINT...EXPECT CONDITIONS SHOULD REMAIN UNDER CRITERIA...SO WILL
NOT ISSUE A SCA AT THIS TIME. STRONGER NW WINDS WILL LIKELY DEVELOP
ON TUESDAY AS CAA STRENGTHENS BEHIND THE DEPARTING LOW. AREAS OF FOG
AND LOW STRATUS WILL CONTINUE TO IMPACT OUR NEARSHORE AREAS THRU
THIS MORNING BEFORE MIXING OUT THIS AFTERNOON.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LHZ345>347.
LM...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR LMZ341-342.
LS...NONE.
&&
$$
UPDATE...JAZ
NEAR TERM...MLR
SHORT TERM...JSL
LONG TERM...JSL
AVIATION...JAZ
MARINE...MLR
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
129 PM EDT MON MAY 18 2015
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 508 AM EDT MON MAY 18 2015
WATER VAPOR LOOP AND RAP ANALYSIS SHOWS MID-LVL LOW ROTATING OVER
NRN MN WITH A DRY SLOT AHEAD OF LOW REACHING ACROSS MUCH OF THE
UPPER MI. COLD FRONT MOVING ACROSS MUCH OF THE AREA OVERNIGHT HAS
ALLOWED DRIER AIR TO ADVECT IN FROM THE SW WHICH HAS DISSIPATED THE
DENSE FOG OVER LAKE MI AND AREAS DOWNSTREAM OVER ERN UPPER MI. DRY
SLOT HAS LEFT UPPER MI GENERALLY PCPN FREE OVER THE EARLY MORNING
HRS.
TODAY AND TONIGHT...THE FOCUS TODAY WILL ON COLD SURGE WHICH WILL BE
MOVING INTO THE WEST MID-LATE MORNING AND CONTINUE EASTWARD THROUGH
THE DAY. AHEAD OF THE FRONT OVER THE EAST HALF OF UPPER MI AND AWAY
FROM THE MODERATING INFLUENCE OF LAKE MICHIGAN...SHOULD SEE
TEMPERATURES REACH IN THE MID TO UPPER 60S (WITH A FEW 70S POSSIBLE
IF THERE ARE BREAKS IN THE LOW CLOUDS). OVER THE WEST HALF WHERE
FRONTAL PASSAGE WILL OCCUR EARLIER...MORNING TO EARLY AFTERNOON HIGH
TEMPS WILL RANGE FROM UPPER 40S/50F NEAR IRONWOOD TO LOWER 60S ALONG
A LINE FM MQT TO MENOMINEE. IN ADDITION...ALL OF THE HIGHER
RESOLUTION MODELS ARE SURGING IN A LAKE BREEZE OFF LAKE SUPERIOR
(FROM MARQUETTE EASTWARD) WHICH WILL LEAD TO COOLER NORTHERLY FLOW
BY MID-LATE AFTERNOON OVER NCNTRL AREAS. WITH THE COLD AIR AND
ABUNDANT MOISTURE SURGING INTO THE AREA AS WINDS TURN
WESTERLY...EXPECT ISOLATED TO SCATTERED SHOWERS TO DEVELOP OVER THE
WEST FIRST (ESPECIALLY IN THE FAVORED UPSLOPE AREAS) AND THEN SPREAD
INTO THE CENTRAL AREAS EVENING AND POSSIBLY EASTERN COUNTIES LATE
EVENING/OVERNIGHT. CAA ON BLUSTERY NW TO N WINDS WILL ALLOW 8H TEMPS
TO FALL TO -8 TO -10C OVER MUCH OF THE WEST HALF OF UPPER MI BY 12Z
TUE. 8H TEMPS WILL FALL TO AROUND -5C OVER THE EAST HALF OVERNIGHT.
BEST FORCING OUT AHEAD ANOTHER SHORTWAVE TRACKING ALONG THE
MN/ONTARIO BORDER TONIGHT WILL STAY MAINLY NW OF UPPER MI KEEPING
MUCH OF THE ASSOCIATED LIGHT PCPN N OF UPPER MI. HOWEVER...DEEP
CYCLONIC FLOW/MOISTURE WILL STILL SUPPORT SOME LIGHT PCPN IN UPPER
MI AS WELL...ESPECIALLY IN THE UPSLOPE AREAS OF THE W AND N. WITH
COLD ADVECTION TAKING PLACE AS NOTED BEFORE...THE -SHRA WILL MIX
WITH OR CHANGE TO -SHSN TONIGHT FROM WEST TO EAST. DUE TO THE COLD
ADVECTION AND PCPN OCCURRING DURING THE OVERNIGHT HOURS...CAN`T RULE
OUT A DUSTING TO LOCALLY A HALFINCH OF SNOW ON GRASSY SFCS BY 12Z
TUE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 407 AM EDT MON MAY 18 2015
TUESDAY WILL BRING ABOUT ONLY SLOWLY RISING TEMPS AS A SECONDARY
TROUGH/COLD FRONT SINKING ACROSS CENTRAL TO E UPPER MI. 850MB TEMPS
AT A CHILLY -10C OVER THE KEWEENAW PENINSULA /2-5C WARMER OFF THE
17/18Z AND 18/00Z GFS RUNS...AS WELL AS THE REGIONAL WRF/. THE NAM
IS THE COLDEST WITH THE ENTIRE W HALF AROUND -11C TUESDAY MORNING.
850MB TEMPS WILL FALL FROM AROUND -4C AT ERY TO AROUND -9C BY 18Z
TUESDAY ON NW WINDS. THIS WILL BE AS ANOTHER SHORTWAVE OVER NE MN AT
12Z SLIDES ACROSS LAKE SUPERIOR. YES...SNOW IS POSSIBLE STILL ON
TUESDAY...BUT MAY BE LIMITED TO JUST A DUSTING ON MAINLY GRASSY
SURFACES THROUGH THE MORNING HOURS...BEFORE THE LOW LEVEL RH
DIMINISHES SIGNIFICANTLY.
EXPECT BREEZY CONDITIONS...WITH GUSTS AVERAGING 20-25KTS ACROSS MUCH
OF THE CWA...STRONGEST ACROSS THE KEWEENAW PENINSULA AND E NEAR LAKE
SUPERIOR. DESPITE LIGHT W FLOW RETURNING AT THE SFC TUESDAY NIGHT
AND 850MB TEMPS WARMING TO AROUND 0C...LOWS NEAR TO SLIGHTLY BELOW
FREEZING WILL BE POSSIBLE /COLDEST IN THE TRADITIONAL COOL SPOTS OF
THE INTERIOR W HALF OF UPPER MI/.
EXPECT DRIER CONDITIONS WITH LIGHTER WINDS WEDNESDAY AS SFC TEMPS
REBOUND TO AROUND 60F. THIS WILL BE DESPITE THE 500MB TROUGH WITH
ITS NW FLOW LINGERING OVERHEAD...AS THE LARGE SFC HIGH OVER THE
DAKOTAS BUILDS A RIDGE ACROSS UPPER MI. PW VALUES SHOULD BE AROUND
0.25IN FROM OVERNIGHT TUESDAY NIGHT THROUGH MUCH OF WEDNESDAY
/ALTHOUGH SLIGHTLY HIGHER NEAR LAKE MI FROM LATE MORNING ON/.
DRY WEATHER SHOULD REMAIN THROUGH THE REST OF THE WORK WEEK AT NW
FLOW LINGERS AT 500MB. THERE WILL BE A WEAK COLD FRONT STRETCHING
ACROSS N LAKE SUPERIOR AT 00Z THURSDAY THAT SINKS ACROSS UPPER MI
WEDNESDAY EVENING AND LOWER MI DURING THE DAY THURSDAY. NOT
EXPECTING MUCH MORE THAN THE POSSIBILITY OF TEMPORARY ADDITIONAL
CLOUD COVER. HIGH PRESSURE WILL SLIDE IN BEHIND THE FRONTAL BOUNDARY
TO WRAP UP THE END OF THE WORK WEEK. EXPECT THIS HIGH TO SHIFT TO
THE LOWER GREAT LAKES BY 18Z SATURDAY AND OFF THE MID-ATLANTIC COAST
SUNDAY MORNING. THIS EXITING HIGH WILL ALLOW MOISTURE TO
RETURN...ALONG WITH A GOOD CHANCE OF SHOWERS FOR SUNDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 128 PM EDT MON MAY 18 2015
WRAPAROUND MOISTURE INTO THE WRN TAF SITES WILL PRODUCE SOME SCT
RAIN SHOWERS THIS AFTERNOON AT IWD AND CMX UNDER MVFR CONDITIONS.
EXPECT CIGS NEAR OF JUST ABOVE THRESHOLD AT SAW UNTIL THIS EVENING
WHEN THE COLDER AIR AND GREATER LOW LEVEL MOISTURE MOVE IN. THE PUSH
OF COLDER AIR BEHIND SECONDARY COLD FRONT WILL CHANGE RAIN SHOWERS
AT KIWD AND KCMX OVER TO SNOW SHOWERS THIS EVENING WITH IFR
CONDITIONS DEVELOPING. SCT -SHRA DEVELOPING AT KSAW EARLY EVENING
WILL ALSO CHANGE OVER TO -SHSN LATE TONIGHT WITH CONDITIONS NEAR
IFR. LOW LEVEL MOISTURE WITH NNW WINDS WILL MAINTAIN MVFR CIGS
INTO EARLY TUE AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 508 AM EDT MON MAY 18 2015
LOW PRES OVER NRN MN WILL MOVE ACROSS LAKE SUPERIOR TODAY INTO THIS
EVENING. AS A RESULT...WINDS ON LAKE SUPERIOR WILL VEER FM SW THIS
MORNING TO NNW LATE TODAY AND TONIGHT AND RAMP UP TO 20 TO 30 KTS
TONIGHT AND TUE...STRONGEST OVER THE EAST HALF. NOT OUT OF THE
QUESTION THAT THERE COULD BE SOME GALE FORCE GUSTS OVER THE E HALF
OF THE LAKE LATE TONIGHT/TUE MORNING. WINDS WILL DIMINISH W TO E TUE
AFTN/NIGHT AS A HIGH PRES RIDGE BUILDS IN FM THE WEST. WED THRU
FRI...WINDS WILL BE UNDER 20KT. LINGERING WARM MOIST AIR WILL ALLOW
FOG TO CONTINUE OVER THE LAKE TODAY...POSSIBLE LOCALLY DENSE OVER
THE EAST HALF THIS MORNING. ALL FOG SHOULD DISSIPATE BY THIS EVENING
AS COLDER AIR ARRIVES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
105 PM CDT MON MAY 18 2015
.UPDATE FOR 18Z AVIATION DISCUSSION...
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 352 AM CDT MON MAY 18 2015
SUB-1000MB LOW OVER NORTHERN MN CONTINUES TO FACILITATE WINDY
CONDITIONS AND STRATUS CLOUDS OVER THE FORECAST AREA EARLY THIS
MORNING. SLIGHT LOOSENING OF THE PRESSURE GRADIENT AS THE TROUGH
WEAKENS AND LIFTS TO THE GREAT LAKES SHOULD ALLOW WINDS TO DIP
BELOW WIND ADVISORY CRITERIA TODAY /SUSTAINED 30 MPH/...SO WILL
NOT REISSUE THE WIND ADVISORY. HOWEVER...IT WILL REMAIN QUITE
BREEZY THROUGH THE DAY. MEANWHILE...THE EXTENSIVE AREA OF SHOWERS
OVER NORTHERN MN AND THE EASTERN DAKOTAS WILL SLIP SLIGHTLY
FARTHER SOUTH INTO CENTRAL MN THIS MORNING. HAVE MAINTED HIGH
CHANCE POPS ACROSS CENTRAL MN TOWARD NORTHERN WI...AND ALSO
INCLUDED SPRINKLES FARTHER SOUTH TO INCLUDE THE TWIN CITIES AND
AREAS DOWN TOWARD SOUTH CENTRAL MN.
TEMPERATURES TODAY WILL BE QUITE CHILLY...AVERAGING 25 TO 30
DEGREES BELOW NORMAL. HIGHS WILL STRUGGLE TO REACH 40 IN WEST
CENTRAL MN NEAR ALEXANDRIA...WHILE THE REMAINDER OF THE AREA WILL
SEE HIGHS IN THE 40S. TEMPS TONIGHT WILL BE AROUND 10 TO 15
DEGREES BELOW NORMAL...WITH ANTICIPATED LOWS IN THE LOW TO MID
30S. HAVE INCLUDED THE MENTION OF FROST IN THE FORECAST...BUT WILL
HOLD OFF ON ANY SORT OF A FROST/FREEZE ADVISORY GIVEN SCT-BKN
CLOUDS ARE EXPECTED TO HANG IN UNTIL THE EARLY MORNING HOURS OF
TUESDAY...AND WINDS WILL BE IN THE 6-10 MPH RANGE.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 352 AM CDT MON MAY 18 2015
NOT MUCH CHANGE IN THE EXTENDED PERIOD AS WAS PREVIOUSLY ADVERTISED
WITH A COOL PERIOD THIS WEEK...THEN WETTER NEXT WEEKEND.
THE MEAN UPPER LEVEL FLOW WILL START THIS WEEK FROM THE W-NW
DIRECTION WHICH SHOULD KEEP A STORM SYSTEM MOVING OUT OF THE
SOUTHERN ROCKIES AND INTO THE MIDWEST...SOUTH OF OUR REGION.
BASICALLY THE CONFLUENT FLOW ALOFT AND DRY E/NE FLOW IN THE BOUNDARY
LAYER WILL KEEP ANY PRECIPITATION CHANCES IN FAR SOUTHERN MN. EVEN
IN THIS AREA...VERY LIGHT PRECIPITATION IS EXPECTED...BUT THE DENSER
CLOUD COVER...AND THE CHANCE OF PRECIPITATION...WILL KEEP TEMPS A
FEW DEGREES COOLER THAN NORTH IN CENTRAL MN WHERE MORE SUNSHINE WILL
OCCUR.
CLIMATOLOGY...THIS WEEK WILL REMAIN ON THE COOL SIDE WITH AFTN HIGHS
SLOWLY REBOUNDING INTO THE UPPER 60S/LOWER 70S BY THURSDAY/FRIDAY.
THE UPPER LEVEL FLOW WILL BEGIN TO BUCKLE BY THE END OF THE WEEK AS
A STORM SYSTEM KICKS OUT OF THE SW CONUS...AND A STRONGER RIDGE
BUILDS IN THE SE CONUS. THIS WILL LEAD TO A WARMER AND UNSETTLED
PATTERN BY NEXT WEEKEND. HOWEVER...BASED ON THE CURRENT MODELS
DEPICTION OF THE MAIN SFC FRONT ALONG AND SOUTH OF MN/IA BORDER...MN
AND WESTERN WI MAY BE ON THE COOL SIDE WITH OCCASIONAL
SHRA/TSRA...BUT NOT AS WARM. THIS COULD CHANGE IF THE RIDGE IN THE
SOUTHEASTERN CONUS STRENGTHENS AND ALLOWS THIS SFC FRONT TO MOVE
FURTHER NORTHWARD INTO MN. THIS WOULD ALSO LEAD TO MORE SVR WX
CHANCES AS WE WOULD BE IN THE WARM SECTOR.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1257 PM CDT MON MAY 18 2015
WIDESPREAD MVFR CIGS ACROSS THE AREA. SOME RESIDUAL
SPRINKLES/LIGHT SHOWERS AROUND. STILL HAVE COLD POOL TO MOVE OVER
THE AREA INTO TONIGHT.THE HRRR CONTINUES TO SHOW SOME ISOLD -SHRA
INTO TONIGHT AS WEAK SURFACE TROUGH MOVES SOUTHEAST OVER THE
NORTHERN CWA. THIS MAY AFFECT CLOUD TRENDS...ESPECIALLY TO THE
EAST OVERNIGHT. SOME DRIER AIR TRYING TO WORK OVER SOUTHWEST
AREA...WITH MORE CUFORM CLOUDS THIS AFTERNOON. MAY SEE HIGHER END
MVFR OR IFR CONDITIONS AT A FEW LOCATIONS IN MN THIS AFTERNOON.
WILL TRY AND SCATTERED CLOUDS TO THE WEST OVERNIGHT AS DRIER AIR
MOVES EAST. THEY MAY HOLD FIRM FARTHER EAST...BUT OVERALL
CONFIDENCE IN CLOUD TREND IS LOW AT THIS TIME. WEST TO NORTHWEST
WINDS OVER THE AREA GUSTS OVER 30KT TO THE WEST...SHOULD GRADUALLY
DIMINISH INTO THE EVENING FROM WEST TO EAST. NORTHWEST/NORTH WINDS
GENERALLY 10-15 KTS INTO TUE WITH CLEARING TREND.
KMSP...
MVFR CIGS INTO THE NIGHT WITH VFR TRENDS INTO TUESDAY MORNING.
SOME QUESTION AS TO HOW LOW CIGS MAY DROP AGAIN INTO THE HE
EVENING AS A WEAK SURFACE TROUGH APPROACHES FROM THE NORTH. WILL
HAVE TO MONITOR THIS INTO THE EVENING. SOME SMALL CHANCE OF
-RA/-DZ ASSOCIATED WITH THIS FEATURE AS WELL...BUT FORCING IS
LACKING. NORTHWEST WINDS A BIT GUSTY INTO THE EVENING BECOMING
MORE NORTH INTO TUESDAY.
/OUTLOOK FOR KMSP/
WED...VFR. WINDS N 5 KTS.
THU...VFR. WINDS NNW 5 TO 10 KTS.
FRI...VFR. WINDS NE 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
SHORT TERM...LS
LONG TERM...JLT
AVIATION...DWE
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1104 AM CDT MON MAY 18 2015
.UPDATE...LARGE CONVECTIVE COMPLEX AFFECTING MAINLY SW PORTIONS HAS
BEEN RESPONSIBLE FOR PROLIFIC RAINFALL AMOUNTS OVERNIGHT AND THIS
MORNING. WHILE AREAS AROUND VICKSBURG SAW THE GREATEST AMOUNTS
OVERNIGHT AND EARLY THIS MORNING...EMPHASIS NOW HAS SHIFTED SOUTH
WITH THE ADVANCING COLD POOL AND A NEW SURGE OF CONVECTION DEVELOPING
OVER W LA. MOISTURE TRANSPORT VECTORS FROM THE HRRR AND NAM SUGGEST
THAT THE HEAVIEST RAINFALL THIS AFTERNOON WILL OCCUR IN FAR EC LA AND
SW PORTIONS OF MS. HAVE THEREFORE REPOSITIONED THE FFA TO ACCOUNT FOR
THIS. HAD TO MODIFY POP/WX GRIDS BASED ON CURRENT TRENDS. ALSO...MADE
ADJUSTMENT TO TEMPS AS CLOUDS/RAIN WILL SIGNIFICANTLY IMPACT WARMTH
OVER THE AREA THIS AFTERNOON./26
&&
.AVIATION...AREA RADARS WERE PICKING UP NUMEROUS SHRA/TSRA ACROSS
THE WEST HALF OF THE REGION. EXPECT IT TO SPREAD ACROSS THE REGION
CAUSING PERIODS OF CIG/VISBY IN IFR/MVFR CONDITIONS IN HEAVIER
RAINFALL. EXPECT RAIN CHANCES TO CONTINUE THROUGH TUESDAY MORNING.
SO MVFR/IFR CIGS WILL CONTINUE WITH PERIODS OF RAIN OVERNIGHT INTO
TUESDAY MORNING./17/
&&
.PREV DISCUSSION... /ISSUED 447 AM CDT MON MAY 18 2015/
DISCUSSION...
SHORT TERM (TODAY THROUGH TUESDAY NIGHT)...IT HAS BEEN AN ACTIVE
OVERNIGHT PERIOD AS AN MCV HAS INCITED PERSISTENT CONVECTION ACROSS
THE REGION. AFTER A TEMPORARY LULL IN INTENSITY/COVERAGE SHORTLY
AFTER MIDNIGHT...CONSIDERABLE NEW DEVELOPMENT OCCURRED ACROSS NORTH
LOUISIANA OVER THE PAST FEW HOURS. MODEL GUIDANCE...PARTICULARLY HIGH
RES GUIDANCE...HAS HAD AN EXTREMELY DIFFICULT TIME WITH DETAILS IN
THIS PATTERN DUE TO POOR INITIALIZATION. THUS LESS FOCUS WAS PLACED
ON ACTUAL QPF OUTPUT THAN THE OVERALL SYNOPTIC PICTURE.
WITH THAT IN MIND...AN UNSEASONABLY MOIST AIRMASS CURRENTLY RESIDES
ACROSS THE AREA (PARTICULARLY THE NORTHWESTERN PORTION OF THE
CWA)...WITH PWATS AROUND 2 INCHES (NEAR RECORD MAX FOR THIS TIME OF
YEAR). A SURFACE FRONT CURRENTLY EXTENDING ACROSS THE MISSOURI VALLEY
WILL SINK SOUTHWARD TOWARD THE AREA THROUGH THE DAY. AS AN UPPER
SHORTWAVE...WHICH IS CURRENTLY FORCING CONVECTION JUST WEST OF THE
REGION...MOVES EASTWARD SCATTERED TO NUMEROUS SHOWERS AND STORMS
WILL OCCUR ACROSS THE CWA TODAY. RADAR ESTIMATES SUGGEST 2 TO 4
INCHES HAVE ALREADY OCCURRED ACROSS PORTIONS OF THE DELTA...WITH
PERHAPS EVEN HIGHER LOCALIZED AMOUNTS. THUS IN MANY AREAS IT WILL
TAKE LITTLE ADDITIONAL RAIN TO CAUSE FLASH FLOODING. A FLASH FLOOD
WATCH WAS POSTED FOR MUCH OF THE DELTA REGION FOR TODAY TO HIGHLIGHT
THIS POTENTIAL.
THE SURFACE FRONT WILL SAG INTO THE AREA AND STALL ON TUESDAY...
PROVIDING A CONTINUED FOCUS FOR SCATTERED CONVECTION ACROSS THE AREA.
AS HAS BEEN THE CASE OVER THE PAST FEW DAYS...THOUGH LITTLE TO
MARGINAL WIND SHEAR IS EXPECTED SUFFICIENT INSTABILITY MAY EXIST TO
GENERATE SOME STRONG/SEVERE CONVECTION. HOWEVER THIS THREAT SHOULD BE
ISOLATED ENOUGH TO LEAVE MENTION OUT OF THE HWO AT THIS TIME. /DL/
LONG TERM (WEDNESDAY THROUGH MONDAY)...A SUMMERLIKE PATTERN WILL
CONTINUE ACROSS THE REGION THROUGH THE WEEK AS MID/UPPER LEVEL
RIDGING REMAINS IN PLACE. A MOIST AIRMASS WILL BE PRESENT OVER THE
REGION AS PW VALUES REMAIN AROUND 1.6-1.9 INCHES. SOME DRIER AIR MAY
BE PRESENT ACROSS THE NORTH WHICH COULD LIMIT CONVECTION AT TIMES. A
WEAK SFC FRONT WILL REMAIN ACROSS THE SOUTHERN PORTIONS OF THE
FORECAST AREA AND WILL LIKELY SERVE AS FOCUSING MECHANISM FOR MAINLY
DIURNAL SHOWERS AND THUNDERSTORMS. WARM CONDITIONS WILL PREVAIL
THROUGH THE WEEK INTO THE WEEKEND. ANOTHER POTENT WEATHER SYSTEM
ACROSS THE PLAINS WILL TRACK TO THE NORTHEAST AND SEND ANOTHER FRONT
IN OUR DIRECTION FOR EARLY NEXT WEEK...WHICH COULD BRING MORE RAIN TO
THE REGION. /28/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 79 69 86 68 / 77 37 43 25
MERIDIAN 84 69 85 67 / 52 37 46 20
VICKSBURG 78 69 86 69 / 100 43 43 25
HATTIESBURG 87 70 87 69 / 51 33 46 26
NATCHEZ 81 69 85 69 / 100 39 45 31
GREENVILLE 79 69 84 68 / 100 36 31 30
GREENWOOD 79 68 84 66 / 100 37 32 26
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR MSZ047-048-053-
054-059>063.
LA...FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR LAZ015-016-
023>026.
AR...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LAS VEGAS NV
339 PM PDT MON MAY 18 2015
.SYNOPSIS...AN AREA OF LOW PRESSURE WILL MOVE EAST ACROSS NEVADA
TONIGHT RESULTING IN SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS
AROUND ESPECIALLY EARLY AND TO THE NORTH OF LAS VEGAS. SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED AGAIN ON TUESDAY
ACROSS THE SOUTHERN GREAT BASIN. MOST AREAS WILL SEE DRY CONDITIONS
ON WEDNESDAY AND WEDNESDAY NIGHT. A NEW STORM SYSTEM WILL APPROACH
THE AREA ON THURSDAY THEN MOVE ACROSS ON FRIDAY BRINGING ADDITIONAL
CHANCES FOR SHOWERS AND THUNDERSTORMS. A SLOW DRYING AND WARMING
TREND IS EXPECTED FOR THE MEMORIAL DAY WEEKEND.
&&
.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT.
CLARK AND LINCOLN COUNTIES HAVE REALLY SEEN AN ACTIVE DAY AS SHOWERS
AND THUNDERSTORMS GOT GOING SHORTLY AFTER DAYBREAK IN THE NORTHEAST
QUADRANT OF A MID/UPPER LEVEL LOW. THE CENTER OF THIS LOW COULD BE
SEEN THIS AFTERNOON ON WATER VAPOR AND SATELLITE OVER DEATH VALLEY
NATIONAL PARK. DESPITE ONLY 0.53 INCH OF PWAT IN THIS MORNING`S NWS
VEGAS SOUNDING AND RELATIVELY LOW-TOPPED CONVECTION, THERE HAVE BEEN
SOME IMPRESSIVE PRECIPITATION TOTALS TODAY WHERE STRONGER STORMS
DEVELOPED OR ACTIVITY TRAINED. A FEW SPOTS IN SUMMERLIN WEST PICKED
UP OVER AN INCH OF RAIN AS WELL AS ONE GUAGE JUST SOUTH OF INSPIRADA
IN HENDERSON. WHILE WIDESPREAD HEAVY RAIN IS NOT EXPECTED THIS
EVENING, ANY SLOWER MOVING OR STRONGER ACTIVITY COULD DUMP A HALF OF
AN INCH OR MORE OF RAIN ESPECIALLY IF IT TRAINS. GIVEN THE
ATMOSPHERE HAS BECOME WORKED OVER IN AND AROUND THE LAS VEGAS VALLEY
EARLIER TODAY, WE THINK THAT THE INTENSITY OF ACTIVITY IMMEDIATELY
IN AND AROUND THE VALLEY SHOULD STAY TOWARD THE LOW-MODERATE END.
HOWEVER, CLOSER TO THE LOW CENTER IN THE NORTHEAST QUADRANT WHERE
ACTIVITY WAS MORE LIMITED EARLIER TODAY, THINGS COULD BE MORE ACTIVE
IN ESMERALDA, EASTERN INYO AND CENTRAL NYE COUNTIES. THE HRRR AND
LOCAL NMM AND ARW MODELS ALL KEY IN ON THESE AREAS FOR ACTIVITY TO
DEVELOP OR PERSIST THIS EVENING AND THUS POPS WERE ADJUSTED UP IN
THESE AREAS. THESE AREAS MAY BE THE SLOWEST TO SEE ACTIVITY END THIS
EVENING WHILE ELSEWHERE THINGS SHOULD END BETWEEN 7 AND 9 PM. LOW
FREEZING LEVELS HAVE ALSO RESULTED IN STRONGER ACTIVITY PRODUCING
HAIL WITH REPORTS EARLIER TODAY AS LARGE AS AN INCH IN DIAMETER IN
THE MOST INTENSE ACTIVITY. IN ADDITION SNOW LEVELS AROUND 8500 FEET
WERE NOTED AND A LIGHT COATING TO AN INCH OR TWO OF SNOW IS POSSIBLE
IN THE HIGHEST ELEVATIONS UNDER ANY SHOWER OR THUNDERSTORM ACTIVITY
OVERNIGHT.
THE LOW CENTER WILL TRANSITION ACROSS THE AREA TONIGHT WHICH WILL
PLACE US ON THE BACK SIDE OF THE LOW FOR TUESDAY. LINGERING ENERGY
AND MID-LEVEL MOISTURE WILL BE ENOUGH TO TOUCH OFF SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS MAINLY ACROSS THE SOUTHERN GREAT BASIN
BUT OUTSIDE OF LINCOLN AND CENTRAL NYE COUNTIES THE COVERAGE OF
ACTIVITY SHOULD BE LOWER TOMORROW. ONCE AGAIN, LOW FREEZING LEVELS
WILL ALLOW FOR HAIL IN ANY STRONGER ACTIVITY. HIGH TEMPS SHOULD WARM
UP SEVERAL DEGREES AS DRIER AIR WORKS IN AND ERODES AWAY THE CLOUDS
OVER THE MOJAVE DESERT.
ANOTHER LOW WILL APPROACH THE COAST OF CALIFORNIA ON WEDNESDAY. THIS
WILL SPREAD LOTS OF HIGH LEVEL MOISTURE INTO THE AREA AS THE JET
STREAM PASSES BY ACROSS SOCAL INTO ARIZONA RESULTING IN A DECENT
AMOUNT OF CIRRUS CLOUDS TO START TO THE DAY AND AGAIN WEDNESDAY
NIGHT. OTHERWISE, THE BEST MOISTURE AND INSTABILITY WILL BE OVER THE
SOUTHERN SIERRA CREST AND EASTERN SLOPES AS WELL AS ESMERALDA COUNTY
AND A FEW SHOWERS AND THUNDERSTORMS ARE POSSIBLE HERE MAINLY IN THE
AFTERNOON. THE REST OF THE AREA LOOKS DRY WITH WINDS PICKING UP FROM
THE SOUTH IN THE AFTERNOON AND EVENING AND GUSTING TO 20-30 MPH.
HIGH TEMPS SHOULD WARM BACK UP ANOTHER 3-5 DEGREES OVER TUESDAY.
THIS LOW WILL EVENTUALLY LOOP BACK OUT AND MERGE WITH ANOTHER LOW
THAT HEADS TOWARD THE COAST ON THURSDAY.
.LONG TERM...THURSDAY THROUGH MONDAY.
THE NEXT UPPER LOW WILL APPROACH THE CENTRAL CALIFORNIA COAST
THURSDAY. A SHORTWAVE ROTATING AROUND THE LOW WILL MOVE NORTHEAST
INTO CALIFORNIA AND NEVADA DURING THE DAY. AN AREA OF DIFFLUENCE AND
DECENT MID LEVEL MOISTURE WILL LEAD TO A CHANCE OF SHOWERS OVER MUCH
OF INYO COUNTY AND ACROSS ESMERALDA...CENTRAL NYE AND NORTHERN
LINCOLN COUNTIES. THE UPPER LOW WILL MOVE INLAND THURSDAY NIGHT AND
ACROSS SOUTHERN NEVADA INTO NORTHWEST ARIZONA FRIDAY. PRECIPITATION
CHANCES WILL THUS SPREAD EAST ACROSS A GOOD PORTION OF THE FORECAST
AREA...MAINLY NORTH OF INTERSTATE 40. WITH THE LOW MOVING
OVERHEAD...HIGH TEMPERATURES FRIDAY WILL BE SOME 10 TO 15 DEGREES
BELOW NORMAL. PRECIPITATION CHANCES WILL DECREASE AND SHIFT
NORTHEAST FRIDAY NIGHT AS THE LOW STARTS TO EXIT THE AREA.
HOWEVER...A SHORTWAVE TROUGH FOLLOWING BEHIND FROM THE NORTH WILL
BRING A CHANCE OF SHOWERS SATURDAY TO AREAS MAINLY NORTH OF LAS
VEGAS.
FOR SUNDAY THROUGH MONDAY THE MODELS ARE NOT IN VERY GOOD AGREEMENT
BUT IN GENERAL IT LOOKS LIKE THERE WILL BE SOME SORT OF UPPER TROUGH
ROUGHLY OVER NORTHERN NEVADA. THIS WOULD KEEP AT LEAST A SLIGHT
CHANCE OF SHOWERS OVER THE FAR NORTHERN PART OF THE FORECAST AREA
AND I LEFT SLIGHT CHANCE POPS IN FOR THOSE AREAS.
&&
.AVIATION...FOR MCCARRAN...SCT SHRA AND ISO TSRA WILL CONTINUE
THROUGH AROUND 03Z TUESDAY. BASES COULD LOWER TO 5K-8K FEET IN AND
NEAR SHRA/TSRA AND WINDS MAY BECOME GUSTY AND ERRATIC POTENTIALLY
IMPACTING CONFIGURATIONS. OVERALL IT APPEARS WE SHOULD SEE AN
DOWNWARD TREND IN SHRA AND TSRA ACTIVITY BY LATER THIS EVENING IN
THE LAS VEGAS VALLEY AS WELL AS IN MOST OF THE APPROACH CORRIDORS
WITH THE BEATTY CORRIDOR LIKELY TO SEE ACTIVITY LINGER THE LONGEST.
WINDS OTHERWISE SHOULD FOLLOW TYPICAL DIURNAL DIRECTIONS AT 8 KTS OR
LESS THROUGH TUESDAY EVENING WITH CLOUDS GRADUALLY DECREASING AND
MAINLY ABOVE 10K FEET. ALTHOUGH CONDITIONS LOOK DRY IN THE LAS VEGAS
VALLEY ON TUESDAY, ISO SHRA/TSRA ARE POSSIBLE IN THE SPRING
MOUNTAINS. ADDITIONAL SHRA AND TSRA CHANCES EXIST FOR FRIDAY AND
FRIDAY NIGHT IN THE LAS VEGAS VALLEY.
FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST
CALIFORNIA...SHRA/TSRA ARE EXPECTED MAINLY NORTH OF KIYK-KLAS-KIGM
LINE WITH ACTIVITY GRADUALLY DIMINISHING BETWEEN 03Z AND 06Z TUESDAY.
ISOLATED SHRA/TSRA ACTIVITY MAY LINGER THOUGH THE NIGHT ESPECIALLY
IN THE SOUTHERN GREAT BASIN. SHRA/TSRA WILL AGAIN BE POSSIBLE ON
TUESDAY ESPECIALLY AFTER 18Z NORTH OF KIYK-KDRA-KACZ LINE. WINDS MAY
BE GUSTY AND ERRATIC IN AND NEAR SHRA/TSRA WITH CIGS LOWERING TO 5K-
8K FEET. OTHERWISE LOOK FOR WINDS TO TREND TOWARD TYPICAL DIURNAL
DIRECTIONS AT 10 KTS OR LESS WITH SCT-BKN CLOUDS AOA 10K FEET.
&&
.SPOTTER INFORMATION STATEMENT...SPOTTERS ARE ENCOURAGED TO REPORT
ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING
PROCEDURES.
&&
$$
SHORT TERM/AVIATION...STACHELSKI
LONG TERM...HARRISON
FOR MORE FORECAST INFORMATION...SEE US ON OUR WEBPAGE:
HTTP://WEATHER.GOV/LASVEGAS OR FOLLOW US ON FACEBOOK AND TWITTER
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
309 PM EDT MON MAY 18 2015
.SYNOPSIS...
WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT
IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD
FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON.
&&
.NEAR TERM /THROUGH TUESDAY/...
SCATTERED POPCORN CONVECTION IS BEING SEEN ACROSS THE AREA THIS
AFTERNOON...AS MOIST AIRMASS HEATS UP IN BOUNDARY LAYER HEATING.
OTHERWISE...SLIGHTLY MORE ORGANIZED CONVECTION NOTED OVER EASTERN
KY AND SOUTHERN OH...AS WEAK VORT FEATURE APPROACHES FROM THE
WEST. IT APPEARS THE LATEST RAP RUNS HAVE A FAIR HANDLE ON THE
OVERALL MASS FIELDS AND THE PROGRESSION OF FEATURES ACROSS
TONIGHT. USED A RATHER BROAD BRUSH APPROACH TO COVER POPS THIS
AFTERNOON AND THIS EVENING. HAVE FRONT CROSSING LATE TONIGHT AND
EARLY MORNING. SPEED UP TIMING SLIGHTLY...BY AN HOUR OR TWO...NOT
MUCH TO REALLY MAKE A CHANGE TO THE OVERALL FORECAST.
FOR TEMPS...WILL SEE A FEW DEGREES OF COOLING TUESDAY OVER TODAYS
HIGHS AS COOLER AIRMASS MOVES IN...WITH DRYING OF THE ATMOSPHERIC
COLUMN.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
ZONAL FLOW FOR THE SHORT TERM PART OF THE FORECAST SHOULD PROVIDE
FOR A DRY FORECAST. DO HAVE SLIGHT CHANCE POPS WEDNESDAY NIGHT AS
SEVERAL UPPER LEVEL DISTURBANCES MOVE ACROSS THE NORTHERN OHIO VALLEY
AROUND THE 520+ LOW OVER NEWFOUNDLAND.
WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE
PERIOD...KEEPING THEM BELOW CLIMATOLOGY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
A HIGH BEGINS TO BUILD IN THE GULF OF MEXICO ON SUNDAY...MIGRATES
EAST AND TRIES TO STRENGTHEN. THIS WILL LEAD TO A POTENTIALLY
MESSY FORECAST FOR THE OHIO VALLEY WITH SEVERAL UPPER LEVEL
DISTURBANCES ROTATING AROUND THE CANADIAN LOW PRESSURE SYSTEMS.
HAVE CHANCE POPS ON SUNDAY AND MONDAY AS EXPECT MOISTURE TO BECOME
TRAPPED UNDER THE HIGH. THERE REALLY ISN/T ANYTHING SIGNIFICANT TO
FOCUS ON TO TIME THESE EVENTS.
WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES. TEMPERATURES WILL
RISE THROUGH THE EXTENDED PART OF THE FORECAST.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
ITS DEJA VU ALL OVER AGAIN...AT LEAST FOR ONE MORE DAY. WILL SEE
ISOLD TO SCATTERED CONVECTION THIS AFTERNOON WITH ISOLD IFR IN
MORE INTENSE CONVECTIVE CELLS. IN ADDITION...THERE MAY BE A FEW
ISOLD OUTFLOW BOUNDARIES PRODUCING SOME LOCAL SFC GUSTS IN THE 20
TO 25 KT RANGE. LATEST RADAR SHOWING A SLIGHTLY MORE ORGANIZED
AREA OF...ALBEIT WEAK...CONVECTION MOVING OUT OF EASTERN KY WHICH
SHOULD TRACK ACROSS WESTERN WV AND SE OH THROUGH 23Z. ELSEWHERE
WILL SEE MORE ISOLD DEVELOPMENT FOR THE REMAINING DAYLIGHT HOURS.
AREAS THAT GET RAIN WILL SEE SOME FOG AFTER 10Z AND WILL ALSO SEE
FOG IN AND ALONG THE RIVERS...MUCH THE SAME AS PREVIOUS COUPLE OF
DAYS. LONE EXCEPTION WILL BE KEKN...WHERE FOG SHOULD BE A LITTLE
MORE PREVALENT FOR A SHORT PERIOD OF MORNING IFR.
HOWEVER...A FRONT WILL PASS ON TUESDAY...AND THIS FRONT IS PROGGED
TO BE ALONG THE OH RIVER BY AROUND 12Z. IT WILL SWING THROUGH
DURING THE DAY TUESDAY...HELPING TO SCOUR OUT THE LOW LEVELS FOR
SOME DRIER CONDITIONS TO CLOSE OUT THE PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: COVERAGE OF STORMS COULD HIGHER THAN
EXPECTED...WITH ORE AREAS SEEING IFR OR LOWER CONDITIONS THIS
AFTERNOON AND EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H M M H H H H H H
HTS CONSISTENCY H H H H M H H H H H H H
BKW CONSISTENCY H H M M M M M M M M M H
EKN CONSISTENCY H H M M M M M M M M L L
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H M M M M M H H
AFTER 18Z TUESDAY...
FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT INTO WED MORNING. REDUCE
VISIBILITY POSSIBLE IN AND AROUND THUNDERSTORMS NEXT SUNDAY AND MONDAY.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...FB/KMC
NEAR TERM...KMC
SHORT TERM...FB
LONG TERM...FB
AVIATION...KMC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
236 PM EDT MON MAY 18 2015
.SYNOPSIS...
WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT
IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD
FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON.
&&
.NEAR TERM /THROUGH TUESDAY/...
SCATTERED POPCORN CONVECTION IS BEING SEEN ACROSS THE AREA THIS
AFTERNOON...AS MOIST AIRMASS HEATS UP IN BOUNDARY LAYER HEATING.
OTHERWISE...SLIGHTLY MORE ORGANIZED CONVECTION NOTED OVER EASTERN
KY AND SOUTHERN OH...AS WEAK VORT FEATURE APPROACHES FROM THE
WEST. IT APPEARS THE LATEST RAP RUNS HAVE A FAIR HANDLE ON THE
OVERALL MASS FIELDS AND THE PROGRESSION OF FEATURES ACROSS
TONIGHT. USED A RATHER BROAD BRUSH APPROACH TO COVER POPS THIS
AFTERNOON AND THIS EVENING. HAVE FRONT CROSSING LATE TONIGHT AND
EARLY MORNING. SPEED UP TIMING SLIGHTLY...BY AN HOUR OR TWO...NOT
MUCH TO REALLY MAKE A CHANGE TO THE OVERALL FORECAST.
FOR TEMPS...WILL SEE A FEW DEGREES OF COOLING TUESDAY OVER TODAYS
HIGHS AS COOLER AIRMASS MOVES IN...WITH DRYING OF THE ATMOSPHERIC
COLUMN.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
MADE NO REAL CHANGES WITH THE SHORT TERM PART OF THE FORECAST.
RAISED POPS A BIT IN THE EAST MONDAY NIGHT AHEAD OF THE COLD
FRONT. PW VALUES ARE IN THE 1.5-1.75 INCHES RANGE AHEAD THE FRONT
SO THE PROSPECT OF HEAVY RAIN OVERNIGHT IS STILL POSSIBLE. EVEN
WITH ALL OF THE RAIN THAT HAS FALLEN UP TO THIS POINT THE GROUND
SHOULD BE ABLE TO HANDLE THE SITUATION SO NO REAL CONCERNS. WILL
CONTINUE TO MONITOR THE SITUATION. IT DRIES OUT QUICKLY BEHIND THE
FRONT STARTING TUESDAY NIGHT.
DRY WEATHER WITH PLEASANT TEMPERATURES SHOULD PREVAIL TUESDAY
NIGHT AND WEDNESDAY AS WEAK HIGH PRESSURE BUILDS TO THE WEST
GIVING ZONAL FLOW FOR THE OHIO VALLEY.
WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE
PERIOD.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
NOTHING SIGNIFICANT TO FOCUS ON IN THE LONG TERM. HIGH PRESSURE
BUILDS OVER THE CENTRAL US AND THAT WILL LEAVE ZONAL FLOW OVER THE
OHIO VALLEY. THE EXTENDED FORECAST WILL BE DRY FOR THE MOST PART
BUT CONFIDENCE IS NOT ALL THAT HIGH AS THERE COULD BE A FEW UPPER
LEVEL RIPPLES CAUSED BY THE WEAK FRONT THAT PASSES TO THE NORTH
NEXT WEEKEND. PRECIPITATION CHANCES INCREASING ON SUNDAY.
WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
ITS DEJA VU ALL OVER AGAIN...AT LEAST FOR ONE MORE DAY. WILL SEE
ISOLD TO SCATTERED CONVECTION THIS AFTERNOON WITH ISOLD IFR IN
MORE INTENSE CONVECTIVE CELLS. IN ADDITION...THERE MAY BE A FEW
ISOLD OUTFLOW BOUNDARIES PRODUCING SOME LOCAL SFC GUSTS IN THE 20
TO 25 KT RANGE. LATEST RADAR SHOWING A SLIGHTLY MORE ORGANIZED
AREA OF...ALBEIT WEAK...CONVECTION MOVING OUT OF EASTERN KY WHICH
SHOULD TRACK ACROSS WESTERN WV AND SE OH THROUGH 23Z. ELSEWHERE
WILL SEE MORE ISOLD DEVELOPMENT FOR THE REMAINING DAYLIGHT HOURS.
AREAS THAT GET RAIN WILL SEE SOME FOG AFTER 10Z AND WILL ALSO SEE
FOG IN AND ALONG THE RIVERS...MUCH THE SAME AS PREVIOUS COUPLE OF
DAYS. LONE EXCEPTION WILL BE KEKN...WHERE FOG SHOULD BE A LITTLE
MORE PREVALENT FOR A SHORT PERIOD OF MORNING IFR.
HOWEVER...A FRONT WILL PASS ON TUESDAY...AND THIS FRONT IS PROGGED
TO BE ALONG THE OH RIVER BY AROUND 12Z. IT WILL SWING THROUGH
DURING THE DAY TUESDAY...HELPING TO SCOUR OUT THE LOW LEVELS FOR
SOME DRIER CONDITIONS TO CLOSE OUT THE PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: COVERAGE OF STORMS COULD HIGHER THAN
EXPECTED...WITH ORE AREAS SEEING IFR OR LOWER CONDITIONS THIS
AFTERNOON AND EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H M M H H H H H H
HTS CONSISTENCY H H H H M H H H H H H H
BKW CONSISTENCY H H M M M M M M M M M H
EKN CONSISTENCY H H M M M M M M M M L L
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H M M M M M H H
AFTER 18Z TUESDAY...
FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT INTO WED MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/ARJ
NEAR TERM...KMC
SHORT TERM...FB
LONG TERM...FB
AVIATION...KMC
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
147 PM EDT MON MAY 18 2015
.SYNOPSIS...
WEAK DISTURBANCES AND WARM MOIST AIR MASS WILL CONTINUE TO RESULT
IN PERIODS OF SHOWERS AND THUNDERSTORMS THROUGH TONIGHT. A COLD
FRONT CROSSES TUESDAY. DRYER CONDITIONS BY TUESDAY AFTERNOON.
&&
.NEAR TERM /THROUGH TONIGHT/...
NO UPDATES TO THE NEAR TERM OTHER THAN TO TWEAK POPS BASED ON
CURRENT TRENDS.
PREVIOUS DISCUSSION BELOW...
LATEST RADAR MOSAIC AND SURFACE OBSERVATIONS SUGGEST REGION IS
GENERALLY DRY AT THIS TIME. EXPECT THESE CONDITIONS WILL CONTINUE
THROUGH THE OVERNIGHT HOURS...AND HAVE SLIGHT CHANCE POPS
CONTINUING.
LATEST HRRR SHOWS A SMALL AREA OF SHOWERS...CURRENTLY OVER SOUTHEAST
KENTUCKY...WILL SPREAD NORTHEAST AND INCREASE IN AREAL COVERAGE AS
IT MOVES INTO OUR SOUTHERN COUNTIES LATER THIS MORNING. THE CURRENT
TREND OF THESE SHOWERS HAS BEEN TO WEAKEN. SO NOT SURE HOW MUCH OF
THESE SHOWERS WILL ACTUALLY MAKE IT INTO OUR AREA.
MOST OF THE MODELS THEN INDICATE WEAK DISTURBANCES WILL MOVE ACROSS
THE AREA TODAY INTO TONIGHT. COMBINATION OF THESE DISTURBANCES AND
INCREASING INSTABILITY SHOULD ONCE AGAIN RESULT IN THE DEVELOPMENT
OF SHOWERS AND STORMS TODAY.
LOCALIZED DOWNPOURS ARE ONCE AGAIN POSSIBLE TODAY AND TONIGHT...AND
CAN RESULT IN MINOR FLOODING OF STREETS...CREEKS...LOW LYING AND
POOR DRAINAGE AREAS.
WITH THE LOSS OF DAYTIME HEATING...THE COVERAGE AND INTENSITY OF
THE CONVECTION SHOULD BEGIN TO WANE. HOWEVER...A COLD FRONT...WHICH
IS EXPECTED TO PUSH INTO THE REGION LATE TONIGHT...SHOULD CONTINUE
THE THREAT OF SHOWERS AND STORMS.
CURRENT THINKING IS THAT THE FRONT SHOULD BE LOCATED NEAR OR JUST
EAST OF THE OHIO RIVER AT THE END OF THIS PERIOD.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
MADE NO REAL CHANGES WITH THE SHORT TERM PART OF THE FORECAST.
RAISED POPS A BIT IN THE EAST MONDAY NIGHT AHEAD OF THE COLD
FRONT. PW VALUES ARE IN THE 1.5-1.75 INCHES RANGE AHEAD THE FRONT
SO THE PROSPECT OF HEAVY RAIN OVERNIGHT IS STILL POSSIBLE. EVEN
WITH ALL OF THE RAIN THAT HAS FALLEN UP TO THIS POINT THE GROUND
SHOULD BE ABLE TO HANDLE THE SITUATION SO NO REAL CONCERNS. WILL
CONTINUE TO MONITOR THE SITUATION. IT DRIES OUT QUICKLY BEHIND THE
FRONT STARTING TUESDAY NIGHT.
DRY WEATHER WITH PLEASANT TEMPERATURES SHOULD PREVAIL TUESDAY
NIGHT AND WEDNESDAY AS WEAK HIGH PRESSURE BUILDS TO THE WEST
GIVING ZONAL FLOW FOR THE OHIO VALLEY.
WENT MAINLY WITH ALL BLEND GUIDANCE FOR TEMPERATURES THROUGH THE
PERIOD.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
NOTHING SIGNIFICANT TO FOCUS ON IN THE LONG TERM. HIGH PRESSURE
BUILDS OVER THE CENTRAL US AND THAT WILL LEAVE ZONAL FLOW OVER THE
OHIO VALLEY. THE EXTENDED FORECAST WILL BE DRY FOR THE MOST PART
BUT CONFIDENCE IS NOT ALL THAT HIGH AS THERE COULD BE A FEW UPPER
LEVEL RIPPLES CAUSED BY THE WEAK FRONT THAT PASSES TO THE NORTH
NEXT WEEKEND. PRECIPITATION CHANCES INCREASING ON SUNDAY.
WENT WITH A BLEND OF GUIDANCE FOR TEMPERATURES.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
ITS DEJA VU ALL OVER AGAIN...AT LEAST FOR ONE MORE DAY. WILL SEE
ISOLD TO SCATTERED CONVECTION THIS AFTERNOON WITH ISOLD IFR IN
MORE INTENSE CONVECTIVE CELLS. IN ADDITION...THERE MAY BE A FEW
ISOLD OUTFLOW BOUNDARIES PRODUCING SOME LOCAL SFC GUSTS IN THE 20
TO 25 KT RANGE. LATEST RADAR SHOWING A SLIGHTLY MORE ORGANIZED
AREA OF...ALBEIT WEAK...CONVECTION MOVING OUT OF EASTERN KY WHICH
SHOULD TRACK ACROSS WESTERN WV AND SE OH THROUGH 23Z. ELSEWHERE
WILL SEE MORE ISOLD DEVELOPMENT FOR THE REMAINING DAYLIGHT HOURS.
AREAS THAT GET RAIN WILL SEE SOME FOG AFTER 10Z AND WILL ALSO SEE
FOG IN AND ALONG THE RIVERS...MUCH THE SAME AS PREVIOUS COUPLE OF
DAYS. LONE EXCEPTION WILL BE KEKN...WHERE FOG SHOULD BE A LITTLE
MORE PREVALENT FOR A SHORT PERIOD OF MORNING IFR.
HOWEVER...A FRONT WILL PASS ON TUESDAY...AND THIS FRONT IS PROGGED
TO BE ALONG THE OH RIVER BY AROUND 12Z. IT WILL SWING THROUGH
DURING THE DAY TUESDAY...HELPING TO SCOUR OUT THE LOW LEVELS FOR
SOME DRIER CONDITIONS TO CLOSE OUT THE PERIOD.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z TUESDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: COVERAGE OF STORMS COULD HIGHER THAN
EXPECTED...WITH ORE AREAS SEEING IFR OR LOWER CONDITIONS THIS
AFTERNOON AND EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05
EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
CRW CONSISTENCY H H H H M M H H H H H H
HTS CONSISTENCY H H H H M H H H H H H H
BKW CONSISTENCY H H M M M M M M M M M H
EKN CONSISTENCY H H M M M M M M M M L L
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H M M M M M H H
AFTER 18Z TUESDAY...
FOG/LOW CLOUDS POSSIBLE OVERNIGHT TUE NT INTO WED MORNING.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JSH/ARJ
NEAR TERM...JSH/KMC
SHORT TERM...FB
LONG TERM...FB
AVIATION...KMC
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
140 PM EDT MON MAY 18 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST ACROSS THE AREA THIS EVENING. HIGH
PRESSURE WILL BUILD VERY SLOWLY EAST AND SETTLE INTO THE MID
MISSISSIPPI VALLEY REGION BY THURSDAY. THE HIGH WILL EXTEND A RIDGE
EAST ACROSS THE LOCAL AREA DURING THIS TIME. MORE HIGH PRESSURE WILL
BUILD SOUTHEAST OUT OF CANADA AND MERGE WITH THE EXISTING HIGH
PRESSURE AND BECOME CENTERED OVER OHIO BY SATURDAY MORNING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CONVECTIVE DEVELOPMENT IS TAKING PLACE FROM NEAR SANDUSKY BAY
SOUTHWEST TO NEAR FDY. WITH MODEST AMOUNT OF WIND SHEAR WE DON`T
EXPECT MUCH IN THE WAY OF SEVERE POTENTIAL. DCAPE IS LOW GIVEN THE
RATHER HUMID CONDITIONS WITH HIGH PRECIPITABLE WATER AMOUNT NEAR 1.6
INCHES. THE HRRR TIMING OF CONVECTIVE DEVELOPMENT IS SLOW BY A
COUPLE OF HOURS. THE LATEST MESO ANALYSIS DATA SHOW LOW LEVEL CIN
HAS DISSIPATED. EXPECT CONVECTIVE ACTIVITY TO INCREASE IN COVERAGE
AND PROGRESS TO THE NORTHEAST. SHORT RANGE MESOSCALE MODELS
SUGGEST THAT NUMEROUS SHOWERS AND THUNDERSTORMS WILL FORM OVER
NORTHEAST OHIO ESPECIALLY IN THE SNOW BELT COUNTIES EAST OF CLE.
GIVEN THE RATHER DEEP MOISTURE AND LIMITED SHEAR SEVERE POTENTIAL
IS LOW.
HAVE RAISED MAXIMUM TEMPERATURE JUST SLIGHTLY IN SPOTS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
COLD FRONT FINALLY ARRIVES AND IS EXPECTED TO SWEEP EAST ACROSS THE
FORECAST AREA FROM WEST TO EAST BETWEEN 00Z AND 06Z TONIGHT. DRY
SLOT IS EXPECTED TO RACE NORTH AHEAD OF THE FRONT INTO THE AREA AS
WELL LIMITING THE EFFECTS FRONT HAS ON PRODUCING SHOWERS AND
THUNDERSTORMS. FRONT PUSHES EAST LATE TONIGHT DIMINISHING THREAT FOR
SHOWERS AS WELL AS NEGATIVE VORTICITY ADVECTION AND DRIER AIR MOVE
INTO THE REGION.
HIGH PRESSURE RIDGE BUILDS EAST INTO THE AREA TUESDAY THROUGH
WEDNESDAY AND BRINGS A RETURN BACK TO FAIR WEATHER ONCE AGAIN.
NOW...THIS IS WHERE THE MODELS SHOW SOME DIFFERENCES. NAM IS THE
WETTEST WEDNESDAY NIGHT IN FORCING A FAST MOVING UPPER LEVEL
POSITIVE VORTICITY MAXIMUM EAST INTO THE AREA. THIS FEATURE HAS
QUITE A BIT OF MOISTURE WITH IT. THE GFS IS SHOWING A SIMILAR
SOLUTION BUT IS LIMITED IN MOISTURE WHERE AS THE SREF SHUNTS
EVERYTHING SOUTH. SINCE THERE ARE SO MANY DIFFERENCES IN TIMING AND
AREAL EXTENT OF THE PRECIPITATION THREAT...WILL JUST MENTION A
SLIGHT CHANCE FOR SHOWERS AT THIS TIME AND SEE IF THE MODELS CAN
COME TO SOME KIND OF CONSENSUS.
UPPER LEVEL FEATURE PULLS OUT TO THE EAST THURSDAY AND BRINGS A
RETURN BACK TO FAIR WEATHER THURSDAY AFTERNOON AND NIGHT.
THE BAD NEWS IS THAT CHILLY AIR WILL RETURN BEHIND THE COLD FRONT
DROPPING TEMPERATURES BACK INTO THE 50S FOR HIGHS ACROSS THE
NORTHERN TIER COUNTIES BY WEDNESDAY AND LOWER 60S ACROSS THE SOUTH.
OVERNIGHT LOWS WILL DROP INTO THE 40S. A BIT OF A REBOUND WITH MORE
SUN WILL RETURN ON THURSDAY WITH HIGHS IN THE LOWER TO MIDDLE 60S.
YET LOWS WILL STILL BE IN THE 40S THURSDAY NIGHT. NOT EXPECTING ANY
FROST THROUGH THE PERIOD AT THIS TIME.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
THE LONG TERM BEGINS FRIDAY WITH A COLD FRONT HAVING JUST DROPPED
SOUTH ACROSS THE REGION AND AN UNREASONABLE AMOUNT OF COLD AIR JUST
TO OUR NORTH. DURING THE DAY HIGH PRESSURE WILL BUILD IN FROM THE
WEST AND WHILE TEMPS WILL BE ON THE COOL SIDE...BOTH MODELS TAKE THE
CORE OF THE COLD AIR EAST ACROSS QUEBEC AND NORTHERN NEW ENGLAND.
SATURDAY THE HIGH MOVES EAST AND HEIGHTS BEGIN TO RECOVER AS WARMER
AIR BEGINS TO RETURN TO THE REGION. AN UPPER RIDGE WILL BE MOVING
INTO THE MIDWEST HOWEVER A SURFACE LOW IN THE CENTRAL PLAINS WILL
BEING DEEP MOISTURE INTO THE MID MISSISSIPPI VALLEY UNDER THE
RIDGE. BY SATURDAY NIGHT AND SUNDAY THIS MOISTURE WILL LIKELY BE
SPILLING INTO THE AREA WITH DEEP SOUTHERLY FLOW INTO THE AREA AHEAD
OF A DEVELOPING UPPER TROF IN THE PLAINS. WILL KEEP FORECAST DRY
THROUGH SATURDAY NIGHT BUT BRING MID/HIGH CHANCE POPS IN FOR
SUNDAY. WILL HAVE LIKELY POPS NORTHWEST SUNDAY NIGHT AND MONDAY
WHICH MAY NEED TO BE EXPANDED AS THE FORECAST EVOLVES. TEMPS FRIDAY
FROM THE UPPER 50S NORTHEAST LAKESHORE TO THE LOWER 70S SOUTHWEST.
MOST AREAS WILL SEE LOWER AND MID 70S SATURDAY AND SUNDAY.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
STILL WARM AND HUMID AHEAD OF A COLD FRONT THAT WILL BE CROSSING
THE AREA THIS EVENING. SCATTERED SHOWERS HAVE BEEN ABLE TO POP UP
ALREADY THIS AFTERNOON. ANY OF THESE COULD BRING CONDITIONS DOWN
TO IFR/MVFR BRIEFLY. GAVE IT ANOTHER HOUR OR TWO BEFORE ANY
THUNDER MENTIONED IN THE TAF. COLD FRONT LAGS UNTIL THIS EVENING
AND THIS COULD BRING ANOTHER CHANCE FOR SHRA/TS. REALLY UNCERTAIN
WHAT THE COVERAGE OF ANY TS MIGHT BE THEREFORE JUST WENT WITH VCSH
WITH FROPA AND A PERIOD OF MVFR. POST FRONT EXPECT A RETURN TO
VFR ALTHOUGH GIVEN TIMING...INLAND EAST WILL LIKELY HANG ON TO THE
MVFR A BIT LONGER. VFR CU TUESDAY AND A NORTHWEST WIND...WITH ANY
GUSTS 20 KNOTS OR LESS.
.OUTLOOK... NON-VFR POSSIBLE BEHIND A COLD FRONT IN NE OH/NW PA
TUESDAY NIGHT.
&&
.MARINE...
LOW PRESSURE OVER LAKE SUPERIOR WILL MOVE NORTHEAST ACROSS ONTARIO
TO QUEBEC TODAY. A COLD FRONT EXTENDING SOUTHWEST FROM THE LOW WILL
CROSS LAKE ERIE TONIGHT. SOUTH TO SOUTHWEST FLOW TODAY AND TONIGHT
WILL REMAIN FAIRLY LIGHT. TUESDAY WINDS WILL INCREASE FROM THE WEST
AND SOUTHWEST TO 15 TO 25 KNOTS/ WINDS WILL TURN NORTHWEST TUESDAY
NIGHT AS THE COLD AIR DEEPENS ACROSS THE LAKE. A LARGE AREA OF HIGH
PRESSURE WILL BUILD TOWARD THE LAKE MID WEEK AS IT DROPS INTO THE
CENTRAL PLAINS. ANOTHER COLD FRONT HOWEVER WILL APPROACH FROM THE
NORTH THURSDAY LIKELY DROPPING ACROSS THE LAKE THURSDAY NIGHT OR
EARLY FRIDAY. NO GALES ARE EXPECTED THROUGH THE PERIOD HOWEVER A
SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED SOMETIME TUESDAY AS WINDS
INCREASE...CONTINUING TUESDAY NIGHT AND MOST OF WEDNESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LAPLANTE
SHORT TERM...LOMBARDY
LONG TERM...TK
AVIATION...OUDEMAN
MARINE...TK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1242 PM EDT MON MAY 18 2015
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST ACROSS THE AREA THIS EVENING. HIGH
PRESSURE WILL BUILD VERY SLOWLY EAST AND SETTLE INTO THE MID
MISSISSIPPI VALLEY REGION BY THURSDAY. THE HIGH WILL EXTEND A RIDGE
EAST ACROSS THE LOCAL AREA DURING THIS TIME. MORE HIGH PRESSURE WILL
BUILD SOUTHEAST OUT OF CANADA AND MERGE WITH THE EXISTING HIGH
PRESSURE AND BECOME CENTERED OVER OHIO BY SATURDAY MORNING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CONVECTIVE DEVELOPMENT IS TAKING PLACE FROM NEAR SANDUSKY BAY
SOUTHWEST TO NEAR FDY. WITH MODEST AMOUNT OF WIND SHEAR WE DON`T
EXPECT MUCH IN THE WAY OF SEVERE POTENTIAL. DCAPE IS LOW GIVEN THE
RATHER HUMID CONDITIONS WITH HIGH PRECIPITAL WATER AMOUNT NEAR 1.6
INCHES. THE HRRR TIMING OF CONVECTIVE DEVELOPMENT IS SLOW BY A
COUPLE OF HOURS. THE LATEST MESO ANAYLSIS DATA SHOW LOW LEVEL CIN
HAS DISSIPATED. EXPECT CONVECTIVE ACTIVITY TO INCREASE IN COVERAGE
AND PROGRESS TO THE NORTHEAST. SHORT RANGE MESOSCALE MODELS
SUGGEST THAT NUMEROUS SHOWERS AND THUNDERSTORMS WILL FORM OVER
NORTHEAST OHIO ESPECIALLY IN THE SNOW BELT COUNTIES EAST OF CLE.
GIVEN THE RATHER DEEP MOISTURE AND LIMITED SHEAR SEVERE POTENTIAL
IS LOW.
HAVE RAISED MAXIMUM TEMPERATURE JUST SLIGHTLY IN SPOTS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
COLD FRONT FINALLY ARRIVES AND IS EXPECTED TO SWEEP EAST ACROSS THE
FORECAST AREA FROM WEST TO EAST BETWEEN 00Z AND 06Z TONIGHT. DRY
SLOT IS EXPECTED TO RACE NORTH AHEAD OF THE FRONT INTO THE AREA AS
WELL LIMITING THE EFFECTS FRONT HAS ON PRODUCING SHOWERS AND
THUNDERSTORMS. FRONT PUSHES EAST LATE TONIGHT DIMINISHING THREAT FOR
SHOWERS AS WELL AS NEGATIVE VORTICITY ADVECTION AND DRIER AIR MOVE
INTO THE REGION.
HIGH PRESSURE RIDGE BUILDS EAST INTO THE AREA TUESDAY THROUGH
WEDNESDAY AND BRINGS A RETURN BACK TO FAIR WEATHER ONCE AGAIN.
NOW...THIS IS WHERE THE MODELS SHOW SOME DIFFERENCES. NAM IS THE
WETTEST WEDNESDAY NIGHT IN FORCING A FAST MOVING UPPER LEVEL
POSITIVE VORTICITY MAXIMUM EAST INTO THE AREA. THIS FEATURE HAS
QUITE A BIT OF MOISTURE WITH IT. THE GFS IS SHOWING A SIMILAR
SOLUTION BUT IS LIMITED IN MOISTURE WHERE AS THE SREF SHUNTS
EVERYTHING SOUTH. SINCE THERE ARE SO MANY DIFFERENCES IN TIMING AND
AREAL EXTENT OF THE PRECIPITATION THREAT...WILL JUST MENTION A
SLIGHT CHANCE FOR SHOWERS AT THIS TIME AND SEE IF THE MODELS CAN
COME TO SOME KIND OF CONSENSUS.
UPPER LEVEL FEATURE PULLS OUT TO THE EAST THURSDAY AND BRINGS A
RETURN BACK TO FAIR WEATHER THURSDAY AFTERNOON AND NIGHT.
THE BAD NEWS IS THAT CHILLY AIR WILL RETURN BEHIND THE COLD FRONT
DROPPING TEMPERATURES BACK INTO THE 50S FOR HIGHS ACROSS THE
NORTHERN TIER COUNTIES BY WEDNESDAY AND LOWER 60S ACROSS THE SOUTH.
OVERNIGHT LOWS WILL DROP INTO THE 40S. A BIT OF A REBOUND WITH MORE
SUN WILL RETURN ON THURSDAY WITH HIGHS IN THE LOWER TO MIDDLE 60S.
YET LOWS WILL STILL BE IN THE 40S THURSDAY NIGHT. NOT EXPECTING ANY
FROST THROUGH THE PERIOD AT THIS TIME.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
THE LONG TERM BEGINS FRIDAY WITH A COLD FRONT HAVING JUST DROPPED
SOUTH ACROSS THE REGION AND AN UNREASONABLE AMOUNT OF COLD AIR JUST
TO OUR NORTH. DURING THE DAY HIGH PRESSURE WILL BUILD IN FROM THE
WEST AND WHILE TEMPS WILL BE ON THE COOL SIDE...BOTH MODELS TAKE THE
CORE OF THE COLD AIR EAST ACROSS QUEBEC AND NORTHERN NEW ENGLAND.
SATURDAY THE HIGH MOVES EAST AND HEIGHTS BEGIN TO RECOVER AS WARMER
AIR BEGINS TO RETURN TO THE REGION. AN UPPER RIDGE WILL BE MOVING
INTO THE MIDWEST HOWEVER A SURFACE LOW IN THE CENTRAL PLAINS WILL
BEING DEEP MOISTURE INTO THE MID MISSISSIPPI VALLEY UNDER THE
RIDGE. BY SATURDAY NIGHT AND SUNDAY THIS MOISTURE WILL LIKELY BE
SPILLING INTO THE AREA WITH DEEP SOUTHERLY FLOW INTO THE AREA AHEAD
OF A DEVELOPING UPPER TROF IN THE PLAINS. WILL KEEP FORECAST DRY
THROUGH SATURDAY NIGHT BUT BRING MID/HIGH CHANCE POPS IN FOR
SUNDAY. WILL HAVE LIKELY POPS NORTHWEST SUNDAY NIGHT AND MONDAY
WHICH MAY NEED TO BE EXPANDED AS THE FORECAST EVOLVES. TEMPS FRIDAY
FROM THE UPPER 50S NORTHEAST LAKESHORE TO THE LOWER 70S SOUTHWEST.
MOST AREAS WILL SEE LOWER AND MID 70S SATURDAY AND SUNDAY.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
AIRMASS QUITE MOIST THIS MORNING WITH DEWPOINTS IN THE MID 60S
STILL CONDITIONS REMAIN PRIMARILY VFR ACROSS THE AREA. UPPER
RIDGE JUST EAST OF THE AREA CONTINUES TO KEEP A LID ON CONVECTION.
FOR TODAY...ASIDE FROM PATCHY MVFR EARLY...EXPECTING MOSTLY VFR
CONDITIONS INTO THE AFTERNOON. FOLLOWING THE HRRR...DO EXPECT
SCATTERED SHOWERS/POSSIBLY THUNDER TO DEVELOP AND DRIFT ACROSS
CENTRAL AND EASTERN TERMINALS...MAINLY INLAND FROM ABOUT 16-20Z.
WILL LIKELY SEE ANOTHER SHOT OF SHOWERS/TSTMS THROUGH THE EVENING
AND/OR OVERNIGHT WITH MVFR CONDITIONS AHEAD OF THE APPROACHING
COLD FRONT. DRIEST AIR IS IN THE NORTHWEST SO DID NOT BRING
CONVECTION THERE. OTHERWISE VCTS/VCSH. POST FRONT EXPECT A RETURN
TO VFR ALTHOUGH GIVING TIMING INLAND EAST WILL LIKELY END THE
FORECAST PERIOD REMAIN MVFR.
.OUTLOOK... NON-VFR POSSIBLE BEHIND A COLD FRONT IN NE OH/NW PA
TUESDAY NIGHT.
&&
.MARINE...
LOW PRESSURE OVER LAKE SUPERIOR WILL MOVE NORTHEAST ACROSS ONTARIO
TO QUEBEC TODAY. A COLD FRONT EXTENDING SOUTHWEST FROM THE LOW WILL
CROSS LAKE ERIE TONIGHT. SOUTH TO SOUTHWEST FLOW TODAY AND TONIGHT
WILL REMAIN FAIRLY LIGHT. TUESDAY WINDS WILL INCREASE FROM THE WEST
AND SOUTHWEST TO 15 TO 25 KNOTS/ WINDS WILL TURN NORTHWEST TUESDAY
NIGHT AS THE COLD AIR DEEPENS ACROSS THE LAKE. A LARGE AREA OF HIGH
PRESSURE WILL BUILD TOWARD THE LAKE MID WEEK AS IT DROPS INTO THE
CENTRAL PLAINS. ANOTHER COLD FRONT HOWEVER WILL APPROACH FROM THE
NORTH THURSDAY LIKELY DROPPING ACROSS THE LAKE THURSDAY NIGHT OR
EARLY FRIDAY. NO GALES ARE EXPECTED THROUGH THE PERIOD HOWEVER A
SMALL CRAFT ADVISORY WILL LIKELY BE NEEDED SOMETIME TUESDAY AS WINDS
INCREASE...CONTINUING TUESDAY NIGHT AND MOST OF WEDNESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...LOMBARDY
NEAR TERM...LAPLANTE
SHORT TERM...LOMBARDY
LONG TERM...TK
AVIATION...TK
MARINE...TK
AREA FORECAST DISCUSSION
NWS PORTLAND
249 PM PDT MON MAY 18 2015
.SYNOPSIS...ONSHORE FLOW RETURNS TONIGHT AND TUESDAY WITH PLENTY
OF CLOUDS AND SOMEWHAT COOLER TEMPERATURES. THIS SHOULD RESULT IN
GREATER STABILITY AND CONFINE THE THUNDERSTORM THREAT CLOSER TO THE
CASCADE CREST TUESDAY WITH POTENTIAL TO SPREAD A LITTLE WESTWARD
WEDNESDAY AND THURSDAY. TEMPERATURES SHOULD BE WITHIN A FEW DEGREES
OF NORMAL FOR THE REMAINDER OF THE WEEK.
&&
.SHORT TERM...TONIGHT THROUGH THURSDAY...DEEP CONVECTION AND
THUNDERSTORMS HAVE DEVELOPED OVER THE CASCADES ABOUT ON SCHEDULE.
THEY HAVE TAKEN ON A VERY SLIGHT WESTWARD DRIFT WHICH HAS ALLOWED
THE STORMS A BIT OF LONGEVITY. STRONGEST ACTION HAS BEEN AROUND
DETROIT WITH RADAR INDICATED RAIN RATES AS HIGH AS A COUPLE INCHES
PER HOUR. THERE HAS BEEN ADDITIONAL FORMATION AROUND AND NORTH OF MT
ST HELENS FORTUNATELY...THE WEAK MOVEMENT HAS LIMITED ACCUMULATIONS
TO 0.75 TO 1.00 INCHES OVER AN HOUR. THE NORTHERN END OF THE
CONVECTIVE LINE NEAR DETROIT HAS WEAKENED A BIT AS IT MOVED OVER THE
EASTERN BOUNDARY OF THE FOOTHILL ZONE. LATEST HRRR RUNS STILL
MAINTAIN A PRIMARY THREAT FOR THE STORMS TO CONTINUE OVER THE
CASCADES THIS EVENING BUT IT WILL BE INTERESTING TO SEE HOW LONG
THE VALLEY LASTS BEFORE STARTING CONVECTION. TEMPERATURES ONLY NEED
TO RISE 4 TO 5 DEGREES BEFORE POTENTIALLY BREAKING THE 12Z SLE
SOUNDING MID LEVEL CAP. STILL EXPECT STORMS WILL FORM...WHEREVER
THEY DO...THROUGH THE EARLY EVENING BEFORE WEAKENING CONSIDERABLY
WITH THE LOSS OF HEATING. THEN EXPECT SOME CONVECTIVE DEBRIS SHOWERS
TO LINGER WEST ACROSS THE VALLEY BEFORE DISSIPATING AND DRIFTING
INTO SOUTHWEST OREGON OVERNIGHT.
THE VERY BROAD UPPER TROUGH WILL MOVE LITTLE WITH FAIRLY NON-DESCRIPT
MID AND UPPER LEVEL FLOW PATTERNS REMAINING OVERHEAD MAKING TUESDAY
THROUGH THURSDAY LARGELY A BROKEN RECORD. TUESDAY WILL SEE A BIT OF
A COOL OFF FOR THE LOWER ELEVATIONS AS DEEPENING SURFACE LOW ACROSS
THE COLUMBIA BASIN WILL EVENTUALLY DRAW THE MARINE LAYER BACK IN
ACROSS THE LOWER ELEVATIONS. SEEMS UNLIKELY THE LAYER WILL BE
SUBSTANTIALLY DEEP AND SHOULD SEE SOME AFTERNOON/EVENING CONVECTION
ACROSS CASCADES ONCE AGAIN AND PROBABLY STAYING CLOSER TO THE CREST.
WILL GET A LITTLE WARMER WEDNESDAY AND THURSDAY WITH A LITTLE BIT OF
EASTERLY COMPONENT STORM MOTION TO AT LEAST BRING A THREAT OF THE
HIGH CASCADE STORMS DRIFTING WEST TOWARD THE FOOTHILLS. MAY SEE SOME
LIGHT SHOWER ACTIVITY OVER THE COAST RANGE AND VALLEY AS WELL. /JBONK
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY...PACIFIC NORTHWEST
REMAINS UNDER LONGWAVE TROUGHING THROUGH THE WEEKEND INTO EARLY NEXT
WEEK KEEPING WEATHER AND TEMPERATURES FAIRLY CONSISTENT. EXPECT
AFTERNOON/EVENING SHOWERS IN THE CASCADES FRIDAY AND SATURDAY.
FRIDAY MAY SEE SHOWERS SPILL WESTWARD INTO THE WILLAMETTE
VALLEY...BUT CONFIDENCE IS LOW. HIGH PRESSURE ATTEMPTS TO BUILD
ONSHORE SUNDAY...WHICH COULD PUSH MOST OF THE MOISTURE OFF TO THE
EAST...THOUGH AS MODELS CONTINUE TO TREND WEAKER WITH THIS RIDGE
SUNDAY IS LOOKING MORE LIKELY TO BE SIMILAR TO SATURDAY WITH SHOWERS
IN THE CASCADES. MONDAY WILL SEE A RETURN TO THE PATTERN FAVORABLE
FOR SHOWERS IN THE CASCADES. -MCCOY
&&
.AVIATION...SHOWERS AND THUNDERSTORMS ARE DEVELOPING OVER THE
CASCADES THIS AFTERNOON. THERE IS A CHANCE A FEW OF THESE THUNDERSTORMS
WILL DRIFT WESTWARD AND IMPACT A WILLAMETTE VALLEY TAF SITE OR TWO
LATER TODAY...MOST LIKELY BETWEEN 00Z AND 03Z TUESDAY. CONFIDENCE
IN WHICH SITES WILL BE IMPACTED REMAINS LOW SO WILL KEEP A VCSH IN
THE TAF FOR NOW.
OTHERWISE...INCREASING ONSHORE PRESSURE GRADIENTS THIS AFTERNOON
AND EVENING SHOULD RESULT IN MVFR STRATUS PUSHING BACK SOLIDLY
ONTO THE COAST AND INTO THE COASTAL GAPS OVERNIGHT. THERE IS A
GOOD CHANCE THESE LOWER FLIGHT CONDITIONS WILL IMPACT A FEW
INTERIOR TAF SITES AS WELL.
KPDX AND APPROACHES...SHOWERS AND THUNDERSTORMS ARE DEVELOPING
OVER THE CASCADES THIS AFTERNOON AND WILL LIKELY IMPACT EASTERN
APPROACHES. THERE IS A CHANCE A STORM COULD DRIFT WESTWARD AND
IMPACT THE TERMINAL...MOST LIKELY BETWEEN 00Z AND 03Z
TUESDAY...BUT CONFIDENCE IN THIS SCENARIO PANNING OUT REMAINS
LOW. MVFR CONDITIONS SHOULD RETURN TO THE TERMINAL BETWEEN 12Z AND
18Z TUESDAY. /NEUMAN
&&
.MARINE...SURFACE HIGH PRESSURE AND THERMAL LOW PRESSURE OVER THE
INLAND NORTHWEST WILL MAINTAIN RELATIVELY LIGHT NORTHWESTERLY
WINDS THROUGH THE UPCOMING WEEKEND.
VERY STRONG EBBS WILL LIKELY PRODUCE STEEP EBB CHOP THE NEXT
SEVERAL MORNINGS ON THE COLUMBIA RIVER BAR...BUT SEAS SHOULD
REMAIN SMALL ENOUGH THAT SMALL CRAFT ADVISORIES FOR ROUGH BARS DO
NOT APPEAR NECESSARY. /NEUMAN
&&
.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 MEDFORD OR
207 PM PDT MON MAY 18 2015
.SHORT TERM...MOISTURE CONTINUES TO ROTATE IN OVER OUR AREA FROM
THE EAST AS AN UPPER LOW MOVES INTO THE GREAT BASIN. DYNAMICS ARE
WEAK, BUT THERE IS PLENTY OF INSTABILITY PRESENT FROM THE CASCADE
CREST AND SISKIYOUS EASTWARD, AND NUMEROUS SHOWERS AND ISOLATED
THUNDERSTORMS HAVE ALREADY DEVELOPED. THIS CONVECTION WILL
INCREASE IN COVERAGE AND MIGRATE TOWARD THE WEST THROUGH THE
AFTERNOON. CONVECTION IS ALREADY TRYING TO SPILL OVER ONTO THE
WEST SIDE, BUT IT IS BEING INHIBITED BY THE LITTLE REMAINING CAP.
THE SUN IS PEAKING THROUGH IN THE WEST SIDE VALLEYS AND THE
SURFACE HEATING WILL BREAK THE CAP PRETTY SOON. MESOANALYSIS
INDICATES WE`VE BUILT 500-1000 J/KG OF SURFACE BASED CAPE
OVER JACKSON AND JOSEPHINE COUNTIES ALREADY, WHICH SHOULD BE
RELEASED EVENTUALLY, AND RESULT IN SHOWERS AND THUNDERSTORMS THERE
AS WELL. LATEST RAP AND HRRR GUIDANCE ACTUALLY SHOWS QUITE A LOT
OF CONVECTION OVER THE ROGUE AND ILLINOIS VALLEYS LATER THIS
AFTERNOON. THEY MAY BE A BIT OVERDONE, BUT PEOPLE IN THESE AREAS
SHOULD KEEP AN EYE ON THE SKY. AS OPPOSED TO YESTERDAY, THE SUN IS
ALSO POKING OUT IN THE UMPQUA, AND THEY DO STAND A BETTER CHANCE
OF SEEING SOME THUNDERSTORMS THIS AFTERNOON AS WELL. THERE IS A
LOT OF MOISTURE IN THE PROFILE (PRECIPITABLE WATER IS NEAR AN
INCH) AND THUS ANY OF THESE STORMS WILL BE CAPABLE OF PRODUCING
SMALL HAIL AND HEAVY DOWNPOURS. WITH LITTLE WIND ALOFT TO SPEAK
OF, STRONG WINDS SHOULDN`T BE MUCH OF A CONCERN, BUT WE COULD SEE
GUSTY WINDS AROUND STORMS.
THINGS WILL STABILIZE TONIGHT AS THE BOUNDARY LAYER COOLS, BUT
SHOWERS ARE LIKELY TO CONTINUE OVERNIGHT ALONG THE MOUNTAINS AND
EAST SIDE. AS BROAD TROUGHING REMAINS OVER THE REGION, WE EXPECT
TO REPEAT THIS BASIC DIURNAL PATTERN OF NIGHT TIME SHOWERS AND
MORE WIDESPREAD SHOWERS AND THUNDERSTORMS IN THE AFTERNOONS
TOMORROW THROUGH THURSDAY. WE SHOULD GRADUALLY BECOME MORE STABLE
ON THE WEST SIDE, SO THUNDERSTORMS BECOME LESS OF AN ISSUE. ONE
BIGGER CHANGE I MADE WAS TO INCREASE POPS OVER THE WEST SIDE
TUESDAY NIGHT INTO WEDNESDAY MORNING AS ALL THE MODELS ARE SHOWING
A DEFORMATION BAND FORMING OVER THE AREA. -WRIGHT
.LONG TERM...THE MODELS SHOW THE WEAK UPPER LOW MOVING INTO
ARIZONA WITH WEAK RIDGING BUILDING OFFSHORE. THE GFS SHOWS MORE
RIDGING COMPARED TO THE EC AND BOTH CONTINUE TO SHOW QPF OVER MOST
OF THE AREA. I SUSPECT THE QPF MAY BE OVERDONE NOT ONLY WITH
AMOUNTS, BUT ALSO THE COVERAGE. THUS HAVE SCALED BACK ON POPS FOR
FRIDAY. ANOTHER WEAK UPPER LOW MOVES INTO THE AREA SATURDAY, BUT
THIS ONE WILL BE COMING IN FROM THE NORTHWEST AND IS NOT EXPECTED
TO HAVE ANY OVER WATER TRAJECTORY, THEREFORE MOISTURE WILL BE
LIMITED AND ANY SHOWERS SHOULD BE ISOLATED AND EAST OF THE
CASCADES. THE EC AND GFS DISAGREE WITH THE PROGRESSION OF THE
UPPER LOW SUNDAY AND THE UPSTREAM UPPER LOW. THE GFS KEEPS THE
UPPER LOW OVER THE AREA SUNDAY WHILE THE EC MOVES IT INTO NORTHERN
CAL. FOR NOW WE`LL GO WITH A BLEND BETWEEN THE TWO AND KEEP A
SLIGHT CHANCE OF SHOWERS EAST OF THE CASCADES. THE ENSEMBLE MEAN
SHOWS A LARGE SPREAD IN THIS TIME PERIOD WHICH YIELDS LOWER
CONFIDENCE IN THE FORECAST. -PETRUCELLI
&&
.AVIATION...FOR THE 18/18Z TAF CYCLE...THE MAIN CONCERN INTO THIS
EVENING WILL BE GUSTY AND ERRATIC WINDS NEAR THUNDERSTORMS. A FEW
STORMS COULD ALSO PRODUCE SMALL HAIL. VFR CIGS WILL BE THE DOMINATE
CONDITION INTO THIS EVENING FOR ALL TERMINALS, EXCEPT FOR TEMPORARY
MVFR CIGS WITH PARTIAL MOUNTAIN OBSCURATION AND REDUCED VISIBILITY
IN SHOWERS AND THUNDERSTORMS. THE ATMOSPHERE WILL STABILIZE TONIGHT
AND CIGS WILL LOWER TO MVFR, THEN IFR AT THE COAST. MODELS ALSO SHOW
PLENTY OF LOW LEVEL MOISTURE INLAND TONIGHT AND IT`S POSSIBLE MVFR
CIGS WILL ALSO DEVELOP FOR INLAND LOCATIONS BETWEEN 4-6Z WITH LOCAL
IFR CIGS IN THE UMPQUA BASIN LATE TONIGHT. -PETRUCELLI
&&
.MARINE...UPDATED 200 PM PDT, MONDAY 18 MAY 2015...A PATTERN OF
WEAK HIGH PRESSURE OFFSHORE AND WEAK LOW PRESSURE INLAND WILL
PERSIST MOST OF THIS WEEK WITH LIGHT TO MODERATE NORTH WINDS AND
NORTHWEST SWELL OVER THE WATERS. WINDS WILL APPROACH SMALL CRAFT
ADVISORY LEVELS ON TUESDAY EVENING AND WEDNESDAY MORNING SOUTH OF
CAPE BLANCO. AFTER THIS NORTH WINDS AROUND 10-20 KTS WILL CONTINUE
INTO THE WEEKEND. /CS
&&
.FIRE WEATHER...UPDATED 200 PM PDT, MONDAY 18 MAY 2015...AN UPPER
LOW CENTERED JUST EAST OF THE BAY AREA IS SENDING MOISTURE NORTHEAST
TOWARDS THE AREA. SO FAR ISOLATED STORMS HAVE BEEN CONFINED TO THE
CASCADES EAST, BUT THEY ARE EXPECTED TO BECOME MORE FREQUENT AS THE
AFTERNOON PROGRESSES INTO THIS EVENING. THE LATEST MESOSCALE ANALYSIS
SHOWS HIGHER CAPE VALUES WEST OF THE CASCADES COMPARED TO YESTERDAY
AND THE MOIST LAYER IS MUCH DEEPER ALL THE WAY UP TO 400 MB BASED IN
THIS MORNINGS SOUNDING. THE 700 MB FLOW WILL BE FROM THE EAST TO
NORTHEAST, THERE IS A BETTER CHANCE FOR SHOWERS AND ISOLATED STORMS
TO MAKE THEIR WAY WEST OF THE CASCADES. WITH PLENTY OF MOISTURE
AVAILABLE, THUNDERSTORMS ARE LIKELY TO BE RAIN PRODUCERS AND THEY
WILL BE SLOW MOVERS. SO HEAVY RAINFALL IS POSSIBLE.
THUNDERSTORMS WILL DECREASE THIS EVENING AND END TONIGHT, BUT WE`LL
CONTINUE TO GET MUCH NEEDED RAIN SHOWERS OVERNIGHT TONIGHT.
THE UPPER LOW WILL MOVE EAST AND WEAKEN TUESDAY WITH THE BEST CHANCE
FOR THUNDERSTORMS ALONG AND EAST OF THE CASCADES. THE ATMOSPHERE IS
EXPECTED TO BE MORE STABLE WEST OF THE CASCADES DUE TO A MARINE
INFLUENCE, SO WERE ONLY EXPECTING SHOWERS. -PETRUCELLI
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
CA...NONE.
PACIFIC COASTAL WATERS...NONE.
$$
AREA FORECAST DISCUSSION
NWS PORTLAND
942 AM PDT MON MAY 18 2015
.SYNOPSIS...BROAD BUT ILL-DEFINED UPPER LEVEL LOW PRESSURE WILL
REMAIN OVER MUCH OF THE WESTERN UNITED STATES THE NEXT SEVERAL
DAYS...KEEPING THE WEATHER UNSETTLED IN GENERAL ACROSS THE REGION.
WEAK HIGH PRESSURE OVER EASTERN WASHINGTON HAS WEAKENED ONSHORE FLOW
CONSIDERABLY. WITHOUT THE STRONG MARINE INFLUENCE...TEMPERATURES
WILL BE A FEW DEGREES WARMER INLAND THAN THE PAST FEW DAYS. THIS
WILL DESTABILIZE THE ATMOSPHERE TO THE POINT WHERE THUNDERSTORMS
COULD DEVELOP FROM THE COAST RANGE EASTWARD THIS AFTERNOON AND
EVENING. THE OVERALL AIR MASS IS RATHER MOIST AND STORMS WILL BE
SLOW MOVING...SO THE POTENTIAL IS THERE FOR LOCALLY HEAVY RAIN.
ONSHORE FLOW RETURNS IN FULL FORCE TONIGHT AND TUESDAY WITH PLENTY
OF CLOUDS AND A RETURN TO COOLER TEMPERATURES. THIS SHOULD RESULT IN
GREATER STABILITY AND CONFINE THE THUNDERSTORM THREAT TO AREAS ALONG
AND EAST OF THE CASCADE CREST FOR MUCH OF THE WEEK. AFTER
TODAY...TEMPERATURES SHOULD BE WITHIN A FEW DEGREES OF NORMAL FOR
THE REMAINDER OF THE WEEK.
&&
.UPDATE...SOME CHANGES TO THE FORECAST PACKAGE FOR TODAY AND
TONIGHT...BUT THE OVERALL MESSAGE WILL BE THE SAME. 12Z SALEM
SOUNDING SHOWED A LITTLE STRONGER MID LEVEL CAP WITH TEMPERATURES
FEW DEGREES WARMER THAN THE EARLIER MODEL RUNS INDICATED. LOOKS LIKE
THE 12Z NAM/GFS AND LAST COUPLE HRRR RUNS PICKED UP ON THIS AND HAVE
SOMEWHAT DIMINISHED THE THUNDER THREAT FROM THE WILLAMETTE
VALLEY/PORTLAND METRO AND AREAS WEST. FORECASTED HIGH TEMPS TODAY
WILL STILL BE AROUND THE CONVECTIVE TEMPS SO CONTINUE TO EXPECT A
THUNDERSTORM ALONG THE I-5 CORRIDOR AND WILL LIMIT COVERAGE TO
ISOLATED. THE CASCADES AND FOOTHILLS STILL APPEAR TO HAVE THE FAR
BETTER CHANCE OF SEEING SCATTERED COVERAGE WITH THE HIGHER TERRAIN
ACTING AS THE ELEVATED HEAT SOURCE. THAT WILL MAKE IT EASIER TO
BREAK THROUGH THAT CAP.
THE BIG UNKNOWN WILL BE THE AMOUNT OF STORM MOTION. MODELED STORM
MOTIONS FOR YESTERDAY PRODUCED NORTHERLY DRIFT OF AROUND 5 KTS WHICH
WAS JUST ENOUGH TO KEEP THE DOWNDRAFT AWAY FROM THE UPDRAFT AND GIVE
SOME LONGEVITY TO THE CELLS. MODELED STORM MOTIONS FOR TODAY BROADLY
SHOW ZERO MOVEMENT ACROSS THE AREA. MENTAL MODEL OF THIS PROVIDES
FOR MORE OF A PULSE STORM SITUATION WHERE STORMS MAY PUT OUR A BRIEF
HEAVY RAIN AND SEVERAL LIGHTNING STRIKES BUT THEN COLLAPSE AS THE
UPDRAFT IS CUT OFF BY THE DOWNDRAFT. ENVISION SOMETHING LIKE AN OLD
SCHOOL PINBALL MACHINE EFFECT WHERE COLLIDING OUTFLOW BOUNDARIES
CONVERGE TO PRODUCE A NEW UPDRAFT AS A TRIGGER FOR A NEW CELL.
THUNDERSTORM INITIATION TIMING STILL FAVORS EARLY AFTERNOON FOR THE
CASCADES AND FOOTHILLS WITH IT TAKING UNTIL MID TO LATE AFTERNOON
FOR THE I-5 CORRIDOR. GIVEN THIS WILL BE MORE OF AN AIR MASS
THUNDERSTORM DAY WHERE GROUND HEATING IS THE TRIGGER...FEEL MOST
DEEP CONVECTIVE ACTION SHOULD QUICKLY DIMINISH TOWARDS THE 7 TO 8 PM
HOURS WITH WEAKER NON-THUNDERSTORM SHOWERS CONTINUING TOWARD
MIDNIGHT. LINGERING CONVECTIVE DEBRIS SHOWERS MAY ULTIMATELY HANG ON
AFTER MIDNIGHT BUT MAINLY CLOSER TO LANE COUNTY.
UPDATES SHOULD BE AVAILABLE NOW. /JBONK
&&
.AVIATION...MARINE STRATUS IS CURRENTLY PRODUCING HIGH END IFR TO
LOW MVFR CONDITIONS ALONG THE COAST AND ALONG THE COLUMBIA RIVER.
EXPECT INTERIOR LOCATIONS TO TURN VFR BETWEEN 17Z AND 18Z TODAY.
CONFIDENCE IN TIMING STRATUS BREAKUP ALONG THE COAST IS
LOWER...BUT BASED ON SATELLITE AND MODEL GUIDANCE IT APPEARS VFR
CONDITIONS WILL BE LONGER LIVED AT KONP THAN KAST TODAY.
SHOWERS AND THUNDERSTORMS WILL LIKELY DEVELOP OVER THE CASCADES
THIS AFTERNOON. THERE IS A CHANCE A FEW THUNDERSTORMS WILL DRIFT
WESTWARD AND IMPACT A WILLAMETTE VALLEY TAF SITE OR TWO LATER
TODAY...MOST LIKELY BETWEEN 00Z AND 03Z TUESDAY...BUT LATEST MODEL
GUIDANCE HAS BACKED OFF ON THIS IDEA A BIT. AS A RESULT...CONFIDENCE
IN DETAILS REMAINS LOW AND WILL KEEP A VCSH IN THE TAFS FOR NOW.
OTHERWISE...HEALTHY ONSHORE FLOW THIS AFTERNOON AND EVENING SHOULD
RESULT IN MVFR STRATUS PUSHING BACK SOLIDLY ONTO THE COAST AND
INTO THE COASTAL GAPS OVERNIGHT. THERE IS A GOOD CHANCE THESE
LOWER FLIGHT CONDITIONS WILL IMPACT AT LEAST KPDX AND KTTD BY 15Z
TUESDAY.
KPDX AND APPROACHES...TEMPORARY LOW END MVFR CONDITIONS CURRENTLY
AT THE TERMINAL WILL END BETWEEN 17Z AND 18Z MONDAY. SHOWERS AND
THUNDERSTORMS WILL LIKELY DEVELOP OVER THE CASCADES LATER TODAY
AND COULD DRIFT WESTWARD AND IMPACT THE TERMINAL...MOST LIKELY
BETWEEN 00Z AND 03Z TUESDAY...BUT CONFIDENCE IN THIS SCENARIO
REMAINS LOW. MVFR CONDITIONS SHOULD RETURN TO THE TERMINAL BETWEEN
12Z AND 18Z TUESDAY AS MARINE STRATUS PUSHES UP THE COLUMBIA
RIVER. /NEUMAN
&&
.MARINE...SURFACE HIGH PRESSURE AND THERMAL LOW PRESSURE OVER THE
INLAND NORTHWEST WILL MAINTAIN RELATIVELY LIGHT NORTHWESTERLY
WINDS THROUGH THE UPCOMING WEEKEND. A WEAK UPPER LEVEL LOW
PRESSURE SYSTEM MAY TEMPORARILY SHIFT WINDS OUT OF THE
SOUTH OVER THE WEEKEND...BUT IMPACTS TO WIND SPEEDS APPEAR
NEGLIGIBLE.
VERY STRONG EBBS WILL LIKELY PRODUCE STEEP EBB CHOP THE NEXT
SEVERAL MORNINGS ON THE COLUMBIA RIVER BAR...BUT SEAS SHOULD
REMAIN SMALL ENOUGH THAT SMALL CRAFT ADVISORIES FOR ROUGH BARS DO
NOT APPEAR NECESSARY. /NEUMAN
&&
.PREV DISCUSSION... /ISSUED 307 AM PDT MON MAY 18 2015/
SHORT TERM...TODAY THROUGH WEDNESDAY...AS ADVERTISED FOR SEVERAL
DAYS NOW...TODAY CONTINUES TO BE THE BEST THREAT IN QUITE SOME TIME
FOR SEVERAL NON-SEVERE THUNDERSTORMS TO DEVELOP COAST RANGE EASTWARD.
MAIN THREAT FROM THESE STORMS WILL BE LOCALLY HEAVY RAIN AND POSSIBLY
SMALL HAIL. SOME HIGHLY LOCALIZED AND BRIEF URBAN AND SMALL STREAM
FLOODING ISSUES ARE POSSIBLE IF ANY OF THESE STORMS DEVELOP OVER POOR
DRAINAGE AREAS...ESPECIALLY IF THEY MOVE THROUGH THE DENSER URBAN
AREAS. TODAY WILL BE AN INTERESTING DAY TO WATCH THE RADAR ACROSS
WESTERN OREGON...AND POSSIBLY SOUTHWEST WASHINGTON.
THE INGREDIENTS COMING TOGETHER TODAY TO SUPPORT DEEP CONVECTION AND
THUNDERSTORMS...1. WEAK HIGH PRESSURE OVER EASTERN WASHINGTON HAS
WEAKENED ONSHORE FLOW ACROSS THE FORECAST AREA...LIMITING THE
STABILIZING MARINE INFLUENCE TO MAINLY THE COASTAL AREAS. THIS WILL
CAUSE INLAND TEMPS TO WARM THROUGH THE 70S...POSSIBLY EVEN UPPER 70S
IN THE PORTLAND METRO AREA. 2. SKIES HAVE GENERALLY CLEARED ACROSS
THE FORECAST AREA ASIDE FROM SOME THIN HIGH CLOUDS. THIS SHOULD
REMAIN THE CASE FOR THE FIRST HALF OF THE DAY. THIS WILL ALSO HELP
SFC TEMPS REACH THE CONVECTIVE TEMPS INDICATED ON MODEL SOUNDINGS
COAST RANGE EASTWARD. 3. NAM/GFS BUFR SOUNDINGS AGREE THAT THERE WILL
BE LITTLE TO NO CAP IN THE ATMOSPHERE UP TO THE TROPOPAUSE. IF
SURFACE TEMPS CAN REACH THE CONVECTIVE TEMP OF AROUND 75 DEG F...
THERE IS LITTLE TO STOP PARCELS FROM REACHING THE TROPOPAUSE. DEEP
BUT FAIRLY SKINNY SBCAPE ON THE ORDER OF 750-1500 J/KG IS BEING SHOWN
UP AND DOWN THE WILLAMETTE VALLEY AND CASCADES THIS AFTERNOON WITH
LIFTED INDICES OF -1 TO -4 DEG C. AS A RESULT...EQUILIBRIUM LEVELS
ARE 30-35 KFT...PLENTY DEEP FOR CHARGE SEPARATION AND LIGHTNING TO
DEVELOP.
AS USUAL FOR OUR AREA...THERE ARE AT LEAST A COUPLE CONS FOR THUNDER
TODAY...AT LEAST FOR AREAS WILLAMETTE VALLEY EASTWARD... 1. MODELS
ARE ALREADY OVERESTIMATING THE SFC DEWPOINTS...FORECASTING LOWER 50S
THIS MORNING WHILE DEWPOINTS ARE ACTUALLY IN THE MID TO UPPER 40S. IF
THIS TREND HOLDS...MODEL CAPE/LI VALUES WILL LIKELY BE EXAGGERATED.
2. LITTLE TO NO SHEAR. UPDRAFTS MAY QUICKLY BE OVERWHELMED BY
DOWNDRAFTS...POSSIBLY BEFORE THUNDERSTORMS CAN MATURE. 3. WEAK
FORCING. WITH LITTLE FLOW IN OUR VERY BROAD UPPER LEVEL
LOW...VORTICITY IS HARD TO COME BY. EXPECT VERY LITTLE HELP FROM ANY
SYNOPTIC FEATURES TODAY...DESPITE A WEAK SHORTWAVE DRIFTING WEST
ACROSS THE SOUTHERN PORTION OF OUR CWA.
GIVEN THE CONVECTION WHICH DEVELOPED IN THE CASCADES SUNDAY IN A LESS
FAVORABLE ENVIRONMENT...CONFIDENCE IS HIGHER THAN USUAL THAT
SCATTERED THUNDERSTORMS WILL DEVELOP ALONG THE CASCADES TODAY. THE
SAME ENVIRONMENT FAVORING THUNDER IN THE CASCADES TODAY SHOULD
SUPPORT SCATTERED THUNDERSTORMS POPPING OFF IN THE WILLAMETTE VALLEY
BY MID-AFTERNOON...ASSUMING DEBRIS FROM THE EARLIER CASCADE
THUNDERSTORMS DO NOT LIMIT SFC HEATING TOO MUCH. ADDITIONALLY SPC
SREF CALIBRATED THUNDERSTORM PROBABILITY IS 50-60 PCT ACROSS PORTIONS
OF OUR INTERIOR LOWLANDS...THE HIGHEST I HAVE SEEN IT. THEREFORE WE
ADDED SCATTERED THUNDERSTORM WORDING TO ALL AREAS COAST RANGE
EASTWARD.
GIVEN THE WEAK SHEAR ENVIRONMENT...IT IS DOUBTFUL ANY THUNDERSTORMS
WILL REACH SEVERE LIMITS. MOST CELLS SHOULD BE PULSE-LIKE...ONLY
LASTING FOR A SHORT PERIOD OF TIME WITH LITTLE ORGANIZATION. HOWEVER
WITH PRECIPITABLE WATER VALUES APPROACHING 1 INCH AND VERY WEAK
STEERING FLOW...THERE IS THE POTENTIAL FOR RAINFALL HEAVY ENOUGH TO
CAUSE BRIEF AND LOCALIZED URBAN/SMALL STREAM FLOODING ISSUES. SOME
LOCATIONS WILL RECEIVE NO RAIN AT ALL...WHILE SOME MAY SEE UPWARDS OF
A HALF INCH OF RAIN IN A VERY SHORT PERIOD OF TIME. HIGHLIGHTED THIS
THREAT IN THE GRIDS AND WILL ISSUE A SPECIAL WEATHER STATEMENT
MENTIONING THIS POSSIBILITY FOR THE AFTERNOON/EVENING COMMUTE.
MEANWHILE SEMI-THERMALLY INDUCED LOW PRESSURE WILL DEVELOP OVER THE
COLUMBIA BASIN THIS AFTERNOON...INCREASING THE ONSHORE COMPONENT OF
THE LOW LEVEL FLOW. THIS SHOULD CAUSE A SURGE OF MARINE AIR TONIGHT
WHICH WILL CUT OFF THE THUNDERSTORM THREAT AND YIELD A MOSTLY
CLOUDY...COOLER DAY TUESDAY. TUESDAY HAS SOME POTENTIAL TO BE A LOT
LIKE LAST FRI/SAT...SO DECIDED TO UNDERCUT MOS GUIDANCE BY A FEW
DEGREES FOR HIGH TEMPS. THE STABLE MARINE AIR WILL LIKELY CONFINE ANY
THUNDERSTORMS TO AREAS ALONG AND EAST OF THE CASCADE CREST.
WEDNESDAY IS A BIT OF A TOUGH TEMPERATURE FORECAST AS MODELS SHOW
GOOD AGREEMENT ON HIGHS ONCE AGAIN REACHING THE MID-UPPER 70S FOR THE
INLAND VALLEYS DESPITE CONTINUED ONSHORE PRESSURE GRADIENTS. THE
MARINE LAYER APPEARS A BIT SHALLOWER THAN IT WAS FRI/SAT...SO THERE
IS BETTER CHANCE OF IT MIXING OUT FOR THE AFTERNOON. NONETHELESS WE
DECIDED TO KEEP FCST TEMPS ON THE LOW SIDE OF GUIDANCE FOR WEDNESDAY.
THE SHALLOWER MARINE LAYER MAY LEAD TO A BETTER CHANCE OF THUNDER IN
THE CASCADES WED AFTN/EVE...ESPECIALLY WITH SOME MODELS SUGGESTING
ANOTHER WEAK SHORTWAVE PIVOTING WESTWARD ACROSS OREGON AT THAT TIME.
WEAGLE
LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
WEDNESDAY NIGHT THROUGH SUNDAY...BROAD UPPER-LEVEL TROUGHING REMAINS
IN PLACE THROUGH THE END OF WEEK...WITH SHORTWAVES BRINGING CHANCES
OF RAIN THURSDAY AND FRIDAY AND MAYBE SOME THUNDERSTORMS IN THE
CASCADES. RIDGING SHOWN YESTERDAY IN MODELS FOR THE WEEKEND IS
LOOKING WEAKER...AND LIKELY WON`T PULL US OUT OF THE OVERALL LONGWAVE
TROUGH PATTERN. THAT SAID...WITH WEAK HIGH PRESSURE OVER THE REGION
SATURDAY AND SUNDAY WEATHER COULD DRY OUT FOR THE WEEKEND WITH MOSTLY
SUNNY SKIES. CONFIDENCE IS STILL LOW AS OF NOW DUE TO HOW FAR OUT IN
THE FORECAST PERIOD THIS IS AS WELL AS THE WEAKENING TREND IN THE
MODELS. -MCCOY
&&
.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
657 PM EDT MON MAY 18 2015
.SYNOPSIS...
A COLD FRONT WILL PUSH ACROSS THE AREA TONIGHT AND EARLY
TUESDAY...PRECEDED BY SHOWERS AND THUNDERSTORMS. THE FRONT WILL
USHER IN A COOL...DRY AIRMASS FOR THE MIDDLE OF THE WEEK.
MUGGINESS WILL RETURN OVER THE HOLIDAY WEEKEND.
&&
.NEAR TERM /UNTIL 1 AM TUESDAY MORNING/...
VERY HIGH PWAT AIR SITTING OVER THE AREA. CAPE HAS BEEN SOMEWHAT
LIMITED UNTIL THE LAST 30 TO 60 MINUTES. THE CAP IS BROKEN AND TC
HAS BEEN PASSED. SHOWERS AND THUNDERSTORMS HAVE GROWN OVER ALMOST
ALL OF THE CWA WITH LITTLE TO NO PATTERN OR ORGANIZATION. THERE
HAS BEEN ONE BACK-BUILDING STORM IN SRN LANC CO. BUT THE HIGH
MOISTURE WILL TIELD SOME VERY HIGH RAIN RATES. WILL NEED TO KEEP
AN EYE ON AREAS WHICH RECEIVE MULTIPLE STORMS/BACKBUILD. THESE
SHOWERS WILL CONTINUE INTO THE EVENING. LATEST NAM RUN PUSHES
MOST OF THE RAIN OFF TO THE EAST OF THE SUSQ RIVER SHORTLY AFTER
1 AM.
&&
.SHORT TERM /1 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
THE FIRST NUDGE OF DRY AIR COMES IN UNDER A SHORT WAVE CURRENTLY
OVER KCVG. THIS SHOULD EFFECTIVELY END MOST OF THE SHOWERS. BUT
THE REAL COLD/DRY AIR DOES NOT ARRIVE IN THE WEST UNTIL CLOSE TO
SUNRISE TUES. THUS...A SLIGHT CHC OF A SHOWER WILL BE MENTIONED
FOR MUCH OF THE AREA OVERNIGHT - ESP IN THE EAST. DEWPOINTS DROP
THROUGH THE DAY IN THE NW HALF OF THE AREA...BUT THE SE COULD STAY
MUGGY AND THE SKY SHOULD BREAK UP LATER TONIGHT. SO SUNSHINE WILL
HEAT UP THE ERN VALLEYS. A STORM OR TWO WILL PROBABLY POP UP IN
THE HEATING OF THE DAY THERE...BUT ARRIVAL OF THE DRY AIR WILL
MAKE IT DIFFICULT TO ALLOW ANYTHING TO GROW ENOUGH IN THE WEST TO
PRECIPITATE. FOG AND LOW CLOUDS ARE AGAIN EXPECTED OVER MOST/ALL
OF THE AREA. PERHAPS ONLY THE PLACES WHICH CAN KEEP WIND OVER
5-6KTS THROUGH THE NIGHT - MAINLY HIGHER ELEVS IN THE WEST - CAN
STAY AWAY FROM BAD VISBYS.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
AREA OF SHOWERS/TSTMS WILL BE DEPARTING LATE TUE/EARLY TUE
EVE...ASSOCIATED WITH A COLD FRONT CLEARING THE REGION.
IN IT/S WAKE...RESPECTABLE ANTICYCLONE WILL BUILD IN FROM THE WEST
WITH A PUSH OF NOTICEABLY COOLER AND DRIER AIR FILTERING IN FOR
MIDWEEK. A WEAK WAVE EJECTS EASTWARD FROM THE S PLAINS TOWARD THE
CAROLINA/S ON THU...WHILE TROUGH CONTINUES TO SPIN OVER EASTERN
CANADA. CENTRAL PA REMAINS BETWEEN THESE TWO FEATURES...WHICH WILL
KEEP US DRY. EVEN WITH NW FLOW...DAYTIME TEMPS WILL REBOUND A BIT
WARMER EACH DAY. BUT DIURNAL TEMP RANGES WILL BE FAIRLY LARGE
THANKS TO THE DRIER AIRMASS...WHICH WILL BRING CHILLY MORNINGS.
THE COLDEST CONTINUES TO LOOK LIKE THURSDAY MORNING WHERE THERE
REMAINS A RISK FOR PATCHY FROST...MAINLY OVER THE NORTH-CENTRAL
ZONES WHERE GUIDANCE IS SHOWING POSS FOR MID 30S AOA BFD /JUST IN
TIME FOR THE START OF THE GROWING SEASON/.
THE WEAK LOW OVER CAROLINAS/MID ATLANTIC REGION SLIDES OFFSHORE
FRI...WITH SPRAWLING HIGH PRESSURE AREA BUILDING IN FOR SAT/SUN.
ONCE RIDGE AXIS SLIDES BY SAT NIGHT...HUMIDITY WILL BEGIN TO
INCREASE ON SUNDAY WITH RISING TEMPS /AND ISOLATED CONVECTION
POSS/. EVEN WARMER AND MUGGIER ON MEMORIAL DAY...WITH SCATTERED TO
EVEN NUMEROUS SHOWERS/TSTMS IN THE FORECAST.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
SCT SHRA/TSRA WILL CONTINUE TO FORM ACROSS CENTRAL PA THIS EVENING
IN UNSTABLE AIR MASS AHEAD OF APPROACHING COLD FRONT OVR THE
MIDWEST. ANY OF THESE SHRA/TSRA COULD PRODUCE BRIEF VIS
REDUCTIONS. HOWEVER...THE MAIN AVIATION CONCERN THIS EVENING WILL
BE THE DEVELOPING LOW CIGS ACROSS EASTERN PA...THE RESULT OF
MARINE AIR FLOWING OFF THE ATLANTIC OCEAN. LOWER CIGS ALREADY
NOTED ACROSS NJ AT 22Z AND NEAR TERM MDL DATA SUPPORT IFR CIGS
MOVING INTO KLNS/KMDT BTWN 00Z-02Z. THE IFR MARINE STRATUS DECK
COULD WORK AS FAR WEST AS KIPT OVERNIGHT. FURTHER WEST...EXPECT
IFR CIGS TO DEVELOP AFTER 06Z AT KBFD/KJST...WHERE A PLUME OF
MOISTURE AHEAD OF COLD FRONT WILL ASCEND THE ALLEGHENY
MTNS...PRODUCING THE LOW CIGS. BOTH SREF AND LATEST HRRR SUPPORT
THIS SCENARIO. MOST FAVORABLE CONDS SHOULD BE AT KAOO/KUNV
OVERNIGHT...WHERE SIG REDUCTIONS APPEAR UNLIKELY.
LOW CIGS ACROSS THE W MTNS AND EASTERN PA SHOULD LIFT BY LATE AM.
CAN/T RULE OUT AN ISOLD SHRA/TSRA ACROSS EASTERN PA ARND MIDDAY
WITH PASSAGE OF COLD FRONT. OTHERWISE...EXPECT A RETURN TO
WIDESPREAD VFR CONDS...AS A MUCH DRIER WEST WIND FLOWS IN BEHIND
THE COLD FRONT.
OUTLOOK...
WED-SAT...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...RXR
AVIATION...DANGELO/FITZGERALD
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
118 PM CDT MON MAY 18 2015
.UPDATE...
UPDATED FOR 18Z AVIATION DISCUSSION.
&&
.PREV DISCUSSION... /ISSUED 1100 AM CDT MON MAY 18 2015/
DISCUSSION...
THE MCS THAT MOVED THROUGH OVERNIGHT HAS STABILIZED MUCH OF
THE MIDSOUTH AND THE MAIN FOCUS FOR HEAVY RAIN HAS SHIFTED SOUTH
OF THE AREA. LATEST HRRR INDICATES THAT SCT REDEVELOPMENT WILL
OCCUR THIS AFTERNOON AS AIRMASS TRIES TO DESTABILIZE AGAIN DUE TO
SURFACE HEATING BUT COVERAGE WILL BE LIMITED AND THE WIDESPREAD
HEAVY RAIN THREAT HAS DIMINISHED. AS A RESULT DECIDED TO CANCEL
FLASH FLOOD WATCH EARLY.
SJM
PREV DISCUSSION... /ISSUED 422 AM CDT MON MAY 18 2015/
A WEAKENING MESOSCALE CONVECTIVE SYSTEM (MCS) WAS LOCATED ALONG
THE TN RIVER OF WEST TN INTO NORTHEAST MS EARLY THIS MORNING. THE
MCS WAS PUSHING TO THE NORTHEAST. ANOTHER MCS WAS STRENGTHENING
OVER NORTH LA AND LOOKS LIKE IT MIGHT SKIRT SOUTHERN PORTIONS OF
NORTH MS WITH THE POSSIBILITY OF VERY HEAVY RAINFALL. WITH THE
HEAVIER STORMS EARLIER TONIGHT ACROSS NORTH MS...VERY HEAVY
RAINFALL WAS INDICATED IN SOME SPOTS...IN EXCESS OF 2 INCHES PLUS
PER HOUR AS SHOWN BY DUAL POL RADAR. WILL KEEP THE FLASH FLOOD
WATCH GOING FOR TODAY. LATEST MODELS DID COME IN WITH POPS A
LITTLE LOWER FOR TODAY ESPECIALLY ACROSS AREAS TO THE NORTHWEST
INCLUDING NORTHEAST AR AND THE MO BOOTHEEL. ALSO...MODELS ARE
SHOWING PRECIPITABLE WATER VALUES DECREASING SLIGHTLY FROM THE
NORTHWEST DURING THE DAY. NEVERTHELESS...A COLD FRONT WILL
APPROACH THE REGION FROM THE NORTH TODAY MOVING INTO NORTHEAST AR
LATE THIS AFTERNOON OR EARLY EVENING. INSTABILITY WILL INCREASE
ACROSS THE AREA ALLOWING FOR SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS TO DEVELOP AHEAD OF THE FRONT. PRECIPITABLE WATER
VALUES WILL BE BETWEEN 1.5 AND 2.1 INCHES ACROSS MOST OF THE AREA.
WITH STORMS BEING VERY EFFICIENT RAIN PRODUCERS...THINK LOCALLY
HEAVY RAINFALL COULD STILL BE A PROBLEM LEADING TO FLASH FLOODING.
ALSO... THINK INSTABILITY WILL BE SUFFICIENT TO SUPPORT A FEW
STRONG THUNDERSTORMS WITH STRONG GUSTY WINDS AND SMALL HAIL.
THE COLD FRONT IS FORECAST TO MOVE THROUGH THE MIDSOUTH TONIGHT AND
TUESDAY...ALTHOUGH THE NAM AND ECWMF ARE SLOWER WITH THE PASSAGE OF
THE FRONT THAN THE GFS. THINK THE CHANCE OF SHOWERS AND
THUNDERSTORMS TUESDAY WILL BE MAINLY ACROSS EAST CENTRAL AR INTO
PORTIONS OF NORTH MS. DRIER AND A LITTLE COOLER AIR WILL SPREAD INTO
THE REGION NORTH OF THE FRONT. THUS MUCH OF THE REGION WILL HAVE A
VERY NICE SPRING DAY TUESDAY.
FOR TUESDAY NIGHT INTO THURSDAY...FOLLOWED THE ECMWF / NAM SOLUTION
VERSUS THE GFS. THE ECMWF AND NAM INDICATE THAT THE FRONTAL SYSTEM
WILL PUSH BACK TO NORTH TUESDAY NIGHT WITH THE MIDSOUTH ONCE AGAIN IN
THE WARM SECTOR WEDNESDAY. SURFACE HIGH PRESSURE WILL THEN PUSH THE
FRONT BACK THROUGH THE REGION WEDNESDAY NIGHT AS A COLD FRONT. THIS
WOULD RESULT IN ANOTHER THREAT OF HEAVY RAINFALL AND POSSIBLY A FEW
STRONG TO SEVERE THUNDERSTORMS WEDNESDAY. HOWEVER...CONFIDENCE IS
LOW AND DID NOT MENTION IN THE HAZARDOUS WEATHER OUTLOOK WITH THE
GFS KEEPING THE FRONTAL SYSTEM MORE TO OUR SOUTH AND MOST OF OUR
FORECAST AREA NOT GETTING BACK INTO THE WARM SECTOR.
MODELS DO AGREE THAT DURING THE DAY THURSDAY DRIER AND A LITTLE
COOLER AIR WILL SPREAD IN FROM THE NORTH ENCOMPASSING THE ENTIRE AREA
BY THURSDAY NIGHT. PLEASANT AND DRY SPRING WEATHER WILL OCCUR FRIDAY
AND FOR MOST OF THE AREA SATURDAY. ANOTHER LARGE SCALE UPPER LEVEL
TROUGH WILL APPROACH FROM THE WEST BY THE LATTER HALF OF THE WEEKEND
BRINGING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS...BUT ONCE AGAIN
AS OBSERVED MUCH OF THIS SPRING...THE TROUGH IS FORECAST TO LIFT TO
THE NORTHEAST AS STRONG UPPER LEVEL HIGH PRESSURE IS LOCATED ALONG
THE SOUTHEASTERN UNITED STATES COAST.
JCL
.AVIATION...
18Z TAFS
VFR..MVFR...AND POSSIBLY IFR CONDITIONS ARE EXPECTED THROUGHOUT
THE 24 HR TAF CYCLE. SCATTERED SHOWERS AND THUNDERSTORMS HAVE
STARTED TO FORM NEAR ALL FOUR TAF SITES THIS AFTERNOON. COVERAGE
WILL CONTINUE TO INCREASE THROUGHOUT THE EVENING AND THUNDERSTORMS
COULD DEVELOP AS THE ATMOSPHERE CONTINUES TO DESTABILIZE...
HOWEVER WE WILL NOT SEE COVERAGE LIKE YESTERDAY. CIGS WILL REMAIN
MVFR AND VFR THIS AFTERNOON BEFORE LIFTING AND CLEARING TO VFR
LEVELS OVERNIGHT AT ALL SITES EXCEPT KTUP. FROPA WILL CAUSE WINDS
TO SHIFT TO THE NORTH AROUND MIDNIGHT FOR KJBR...KMEM...AND KMKL.
IFR CONDITIONS WILL BE POSSIBLE AT KTUP OVERNIGHT AND TOMORROW
MORNING.
JPM3
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MEMPHIS TN
1100 AM CDT MON MAY 18 2015
.DISCUSSION...
THE MCS THAT MOVED THROUGH OVERNIGHT HAS STABILIZED MUCH OF
THE MIDSOUTH AND THE MAIN FOCUS FOR HEAVY RAIN HAS SHIFTED SOUTH
OF THE AREA. LATEST HRRR INDICATES THAT SCT REDEVELOPMENT WILL
OCCUR THIS AFTERNOON AS AIRMASS TRIES TO DESTABILIZE AGAIN DUE TO
SURFACE HEATING BUT COVERAGE WILL BE LIMITED AND THE WIDESPREAD
HEAVY RAIN THREAT HAS DIMINISHED. AS A RESULT DECIDED TO CANCEL
FLASH FLOOD WATCH EARLY.
SJM
&&
PREV DISCUSSION... /ISSUED 422 AM CDT MON MAY 18 2015/
A WEAKENING MESOSCALE CONVECTIVE SYSTEM (MCS) WAS LOCATED ALONG
THE TN RIVER OF WEST TN INTO NORTHEAST MS EARLY THIS MORNING. THE
MCS WAS PUSHING TO THE NORTHEAST. ANOTHER MCS WAS STRENGTHENING
OVER NORTH LA AND LOOKS LIKE IT MIGHT SKIRT SOUTHERN PORTIONS OF
NORTH MS WITH THE POSSIBILITY OF VERY HEAVY RAINFALL. WITH THE
HEAVIER STORMS EARLIER TONIGHT ACROSS NORTH MS...VERY HEAVY
RAINFALL WAS INDICATED IN SOME SPOTS...IN EXCESS OF 2 INCHES PLUS
PER HOUR AS SHOWN BY DUAL POL RADAR. WILL KEEP THE FLASH FLOOD
WATCH GOING FOR TODAY. LATEST MODELS DID COME IN WITH POPS A
LITTLE LOWER FOR TODAY ESPECIALLY ACROSS AREAS TO THE NORTHWEST
INCLUDING NORTHEAST AR AND THE MO BOOTHEEL. ALSO...MODELS ARE
SHOWING PRECIPITABLE WATER VALUES DECREASING SLIGHTLY FROM THE
NORTHWEST DURING THE DAY. NEVERTHELESS...A COLD FRONT WILL
APPROACH THE REGION FROM THE NORTH TODAY MOVING INTO NORTHEAST AR
LATE THIS AFTERNOON OR EARLY EVENING. INSTABILITY WILL INCREASE
ACROSS THE AREA ALLOWING FOR SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS TO DEVELOP AHEAD OF THE FRONT. PRECIPITABLE WATER
VALUES WILL BE BETWEEN 1.5 AND 2.1 INCHES ACROSS MOST OF THE AREA.
WITH STORMS BEING VERY EFFICIENT RAIN PRODUCERS...THINK LOCALLY
HEAVY RAINFALL COULD STILL BE A PROBLEM LEADING TO FLASH FLOODING.
ALSO... THINK INSTABILITY WILL BE SUFFICIENT TO SUPPORT A FEW
STRONG THUNDERSTORMS WITH STRONG GUSTY WINDS AND SMALL HAIL.
THE COLD FRONT IS FORECAST TO MOVE THROUGH THE MIDSOUTH TONIGHT AND
TUESDAY...ALTHOUGH THE NAM AND ECWMF ARE SLOWER WITH THE PASSAGE OF
THE FRONT THAN THE GFS. THINK THE CHANCE OF SHOWERS AND
THUNDERSTORMS TUESDAY WILL BE MAINLY ACROSS EAST CENTRAL AR INTO
PORTIONS OF NORTH MS. DRIER AND A LITTLE COOLER AIR WILL SPREAD INTO
THE REGION NORTH OF THE FRONT. THUS MUCH OF THE REGION WILL HAVE A
VERY NICE SPRING DAY TUESDAY.
FOR TUESDAY NIGHT INTO THURSDAY...FOLLOWED THE ECMWF / NAM SOLUTION
VERSUS THE GFS. THE ECMWF AND NAM INDICATE THAT THE FRONTAL SYSTEM
WILL PUSH BACK TO NORTH TUESDAY NIGHT WITH THE MIDSOUTH ONCE AGAIN IN
THE WARM SECTOR WEDNESDAY. SURFACE HIGH PRESSURE WILL THEN PUSH THE
FRONT BACK THROUGH THE REGION WEDNESDAY NIGHT AS A COLD FRONT. THIS
WOULD RESULT IN ANOTHER THREAT OF HEAVY RAINFALL AND POSSIBLY A FEW
STRONG TO SEVERE THUNDERSTORMS WEDNESDAY. HOWEVER...CONFIDENCE IS
LOW AND DID NOT MENTION IN THE HAZARDOUS WEATHER OUTLOOK WITH THE
GFS KEEPING THE FRONTAL SYSTEM MORE TO OUR SOUTH AND MOST OF OUR
FORECAST AREA NOT GETTING BACK INTO THE WARM SECTOR.
MODELS DO AGREE THAT DURING THE DAY THURSDAY DRIER AND A LITTLE
COOLER AIR WILL SPREAD IN FROM THE NORTH ENCOMPASSING THE ENTIRE AREA
BY THURSDAY NIGHT. PLEASANT AND DRY SPRING WEATHER WILL OCCUR FRIDAY
AND FOR MOST OF THE AREA SATURDAY. ANOTHER LARGE SCALE UPPER LEVEL
TROUGH WILL APPROACH FROM THE WEST BY THE LATTER HALF OF THE WEEKEND
BRINGING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS...BUT ONCE AGAIN
AS OBSERVED MUCH OF THIS SPRING...THE TROUGH IS FORECAST TO LIFT TO
THE NORTHEAST AS STRONG UPPER LEVEL HIGH PRESSURE IS LOCATED ALONG
THE SOUTHEASTERN UNITED STATES COAST.
JCL
&&
.AVIATION...
12Z TAFS
WIDESPREAD LIGHT RAINFALL WITH A FEW EMBEDDED LIGHTNING STRIKES
THIS MORNING ACROSS MOST TERMINALS EXCEPT JBR...WHICH HAS MANAGED
TO CLEAR. SIMILAR TO THE PAST FEW DAYS...SHOWERS AND
THUNDERSTORMS ARE FORECAST TO REDEVELOP TOWARD 17Z ACROSS ALL
TERMINALS. COVERAGE OF STORMS SHOULD BE LESS TODAY AND THERE IS A
LITTLE MORE UNCERTAINTY IN THAT ASPECT...BUT VCTS IS IN THE
FORECAST AT ALL TERMINALS TO ACCOUNT FOR THIS AS OF NOW. CLOUD
COVER SHOULD ALSO BE ABUNDANT TODAY...WITH A PERSISTENT BKN TO
OVC DECK. A FRONTAL BOUNDARY SHOULD BRING AN END TO THE PRECIP
LATE THIS AFTERNOON WITH CIGS LIFTING AFTER 00Z. THE EXCEPTION TO
THIS WILL BE TUP WHERE GUIDANCE IS AGGRESSIVE ON DEVELOPING AN
IFR DECK AFTER 06Z. DID NOT BRING CIGS DOWN THAT LOW YET BUT
TRENDED DOWNWARD...SO THIS WILL NEED TO BE WATCHED.
WINDS SHOULD MAINLY BE SOUTH-SOUTHWESTERLY AROUND 10 MPH THROUGH
THE DAY.
TVT
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
MO...NONE.
MS...NONE.
TN...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1255 PM CDT MON MAY 18 2015
.AVIATION...
VFR DETERIORATING TO IFR TONIGHT AT ALL SITES. SURGE OF MOISTURE
INTO THE REGION WILL BREED SCT TSRA SW OF LBB LATER THIS AFTN
BEFORE REACHING LBB AND PVW THIS EVENING. MUCH BETTER CHANCE FOR
WIDESPREAD TSRA DEVELOPMENT SHOULD OCCUR EARLY TUE MORNING FROM
W-E AS AN UPPER TROUGH REACHES THE AREA. IFR CIGS ARE LIKELY TO
PERSIST THRU 18Z TUE AS MOIST E-SE UPSLOPE WINDS PERSIST.
&&
PREV DISCUSSION... /ISSUED 340 AM CDT MON MAY 18 2015/
SHORT TERM...
THE SHORT TERM PERIOD WILL FOCUS ON THE RETURN OF SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS...THAT COULD COMMENCE AS EARLY
AS LATE THIS AFTN.
THE PACIFIC FRONT/DRYLINE THAT AFFECTED THE SOUTHERN PLAINS
YESTERDAY WAS WELL SOUTH AND EAST OF THE CWA EARLY THIS MORNING...AS
HINTED AT BY DEWPOINTS IN THE 60S AND 70S ACROSS THE CONCHO
VALLEY...BIG COUNTRY AND EDWARDS PLATEAU AREAS. AS SUCH...SOME FOG
AND/OR LOW CLOUDS HAVE DEVELOPED ACROSS PORTIONS OF THE SAID AREAS.
COMPUTER MODELS HINT AT THE BOUNDARY RETREATING TO NEAR THE FAR SRN
SOUTH PLAINS AND LOW ROLLING PLAINS BY AOA DAYBREAK...BRINGING WITH
IT RICH LOW LEVEL MOISTURE AND A CHANCE FOR THE FOG AND/OR STRATUS
DECK TO MAKE HEADWAY TOWARDS THE FA. HOWEVER...MODEL SOLUTIONS SUCH
AS THE HRRR AND THE NAM EXHIBIT THE FOG AND LOW CLOUDS TO STOP JUST
SHORT OF THE FA AND DISSIPATE...GIVEN SFC WINDS VEERING TO THE W-SW
THROUGHOUT DAYBREAK AND THUS MITIGATING THE TRANSPORT OF THE LOW
LEVEL MOISTURE. WE WILL CONTINUE TO MONITOR AND SEE IF THIS DOES
INDEED OCCUR.
ATTENTION WILL TURN TO AN UA LOW THAT WAS IMPINGING ON CNTRL/SRN
CALI PER 07Z SATELLITE WATER VAPOR IMAGERY...AND IS PROGGED TO
TRANSLATE ENE TO NEAR THE FOUR-CORNERS REGION BY TONIGHT. AS
SUCH...SW FLOW ALOFT WILL SHARPEN. EMBEDDED WITHIN THIS SW FLOW IS
AN IMPULSE THAT MODEL SOLUTIONS SHOW EJECTING OUT AHEAD OF THE
PARENT UA LOW...AND NEAR THE SWRN ZONES LATE THIS AFTN/EARLY EVENING
AND PROGRESS TO THE NE TO ACROSS THE NERN ZONES BY TONIGHT. WITH SFC
LEE TROUGHING DEEPENING DUE TO THE APPROACHING UA LOW...THIS WILL
AID TO BACK SFC WINDS TO THE S-SE AND PWATS WILL SOAR INTO THE 1.00-
1.50 INCH RANGE BY TONIGHT...WHILST THE LLJ CRANKS UP TO 20-40 KTS.
WITH ALL THAT SAID...CONVECTION IS STILL EXPECTED TO INITIATE ACROSS
THE FAR SW SOUTH PLAINS AS EARLY AS LATE THIS AFTN/EARLY THIS
EVENING...ESPECIALLY IF THE TIMING OF THE ANTICIPATED EMBEDDED
IMPULSE STAYS TRUE. PRECIP WILL BECOME SCATTERED TO PERHAPS
WIDESPREAD AS IT PROGRESSES NE TO ACROSS THE REMAINDER OF THE CWA
THROUGH THE NIGHT. TO ADD FUEL TO THE PROVERBIAL FIRE...A COLD FRONT
WILL BACKDOOR INTO THE REGION THIS EVENING/TONIGHT...WHICH COULD
SERVE AS ANOTHER FOCUS FOR STORM DEVELOPMENT. WITH SUCH HIGH
PWATS...MODERATE-HEAVY RAINFALL CAN NOT BE RULED OUT WHICH RAISES
CONCERNS FOR LOCALIZED FLOODED. WE ALSO NEED TO KEEP AN EYE OUT FOR
SOME STORMS BECOMING STRONG TO SEVERE...ESPECIALLY ACROSS THE SWRN
ZONES LATE THIS AFTN AS PROGGED MUCAPE VALUES OF 2-3 KJ/KG...30-40
KTS OF 0-6 KM BULK SHEAR...STEEPENED LAPSE RATES AND VEERING WIND
PROFILES SAYS AS MUCH /HAIL AND GUSTY WINDS WILL BE THE PRIMARY
THREATS/.
A SEASONABLY WARM DAY WILL PREVAIL WITH HIGHS IN THE 70S AND
80S...FOLLOWED BY OVERNIGHT LOWS IN THE 50S AND 60S.
LONG TERM...
THE WEATHER FOR THE PAST SEVERAL WEEKS /MINUS THE WIND AND LACK
OF 70+ DEGREE DEW POINTS/ HAVE MADE IT FEEL LIKE I AM BACK IN MY
OLD STOMPING GROUNDS IN SOUTH MS...AND IT DOESN/T LOOK LIKE THE
PATTERN WILL CHANGE ANY OVER THE NEXT 7 DAYS AND BEYOND. FOR
STARTERS WPC QPF GUIDANCE PRE 00Z SHOWS UPWARDS OF 5 INCHES OF
RAIN OVER THE NEXT 7 DAYS. TUESDAY MORNING WILL START VERY WET
WITH AN UPPER LEVEL LOW WITH A SLIGHT NEG TILT MOVES OVER NV TOWARDS
THE REGION. MODEL OMEGA FIELDS/SOUNDING PROFILES ALL SHOW LIFT AND
NO SUBSIDENCE BY 7AM THOUGH THEY DO VARY ON THE AMOUNT OF LIFT. THE
GFS HAS THE LEAST AMOUNT OF LIFT WITH THE LEAST AMOUNT OF QPF WHILE
THE NAM/ECMWF ARE FAIRLY IN LINE WITH EACH OTHER. PWAT VALUES WILL
BE RELATIVELY HIGH...1.25 TO 1.5 INCHES ON THE CAPROCK WHILE
APPROACHING 2 INCHES ACROSS THE EASTER ROLLING PLAINS. THIS IS IN
PART DUE TO MOIST SURFACE CONDITIONS AS WELL AS A 40KT LLJ PUMPING
IN MOISTURE FROM THE GOMEX. ONE CONCERN WITH TUESDAY MORNING WILL BE
FLOODING. WITH ALREADY SATURATED SOILS AND FULL PLAYA LAKES RUN
OFF...MAINLY IN URBAN AREAS...WILL BE ALL BUT GUARANTEED WITH A
QUICK 1 INCH RAINFALL CAUSING PROBLEMS. WHILE ACTUAL RAINFALL
AMOUNTS AS WELL AS THE LOCATION OF THE HEAVIEST RAIN IS HARD TO
PINPOINT NEARLY 24 HOURS OUT...THE EXPECTED WIDESPREAD DYNAMIC LIFT
IN ADDITION TO THE RICH MOISTURE TRANSPORT VIA THE LLJ SHOWS THAT
HEAVY RAIN MAY BE FAIRLY WIDESPREAD. GIVEN THAT THIS IS EXPECTED TO
HAPPEN DURING THE MORNING TRAFFIC RUSH AN AREAL FLOOD WATCH MAY BE
WARRANTED. FOR NOW WE WILL DEFER THE WATCH DECISION TO THE NEXT
SHIFT FOR FURTHER EVALUATION OF MORE UP TO DATE INFO. THERE IS A
POSSIBLE SEVERE THREAT LATER TOMORROW AFTERNOON/EVENING DEPENDING ON
HOW MUCH SURFACE HEATING CAN BE ACHIEVED. THIS WILL BE DEPENDENT ON
CLOUD COVER. AS OF NOW OUR WESTERN ZONES HAVE SOMEWHAT HIGHER
CHANCES TO SEE SEVERE STORMS THAN THE REST OF THE FA AS CLOUDS WILL
BEGIN TO THIN FROM WEST TO EAST.
WE SHOULD SEE PRECIP MOVE OFF TO THE EAST BY WED MORNING AS A FRONT
APPROACHES FROM THE NORTH. MODEL TIMING WITH THE FROPA DIFFERS WITH
THE GFS /FRONT PUSHING INTO OUR NORTHERN ZONES BY 00Z THURS/ BEING
SLOWER THAN THE ECMWF /FRONT THRU THE FA BY 00Z/. OTHER THAN A WIND
SHIFT AND CLOUD COVER THIS SHOULDN/T CREATE MUCH OF A HEADACHE AS
FAR AS THE FORECAST IS CONCERNED. THE FROPA WILL BE ACCOMPANIED BY A
LOW STRATUS DECK THAT WILL STICK AROUND FOR MUCH OF WED NIGHT INTO
THURS AFTERNOON. RAIN WILL BE POSSIBLE MAINLY DUE TO ISENTROPIC
LIFTING. THE BIGGEST CHANGE TO THE FORECAST DURING THIS PERIOD IS
MAKING THE PRECIP MAINLY IN THE FORM OF RAIN WITH A MENTION OF ISO
THUNDER AS THE CHANCE EXISTS FOR SOME ELEVATED CAPE. ANOTHER LOW IS
PROGGED TO MOVE INLAND ACROSS SOCAL WHICH WILL RETURN SURFACE FLOW
OUT OF THE SOUTH/SOUTHEAST AND SET UP A DRYLINE OVER CENTRAL NM.
THIS WILL BE OUR NEXT BIG RAIN MAKER AS THE DRYLINE PUSHES EASTWARD
AND THEN RETREATS FRIDAY AND SATURDAY.
TEMPS WILL CONTINUE TO REMAIN BELOW SEASONAL AVERAGE AS CLOUD COVER
WILL BE ABUNDANT THRU THE WEEK AND SURFACE MOISTURE WILL HELP
MODERATE SURFACE TEMPS. THURS WILL BE PARTICULARLY CHILLY WITH TEMPS
AVERAGING 20 DEGREES BELOW SEASONAL AVERAGE /MID 60S/ DUE TO SURFACE
CAA ASSOCIATED WITH THE FROPA. ALDRICH
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
93
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
648 PM EDT MON MAY 18 2015
.SYNOPSIS...
A COLD FRONT EXTENDS FROM MICHIGAN TO SOUTHERN MISSOURI. THIS
FRONT WILL MOVE EAST ACROSS THE OHIO VALLEY OVERNIGHT...CROSSING
THE MID ATLANTIC REGION TUESDAY. MOIST SOUTHERLY FLOW AHEAD OF THE
FRONT WILL HELP FUEL SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS.
ONCE THE FRONT PASSES EAST OF THE AREA TUESDAY...COOLER...DRIER
AIR WILL FILTER INTO THE REGION FOR MID WEEK.
&&
.NEAR TERM /THROUGH TUESDAY/...
AS OF 640 PM EDT MONDAY...
NO MAJOR CHANGES TO THE FORECAST AS WE HEAD INTO THE EVENING
HOURS. WE STILL EXPECT SCATTERED SHOWERS AND SOME STORMS ACROSS
MUCH OF THE REGION. WHAT DID CHANGE WAS THE FOCUS FOR WHERE THE
BEST CHANCES WOULD BE IN THE NEXT COUPLE OF HOURS BASED UPON WHERE
THE GREATEST CONCENTRATION IS CURRENTLY LOCATED...FROM FRANKLIN
COUNTY VA SOUTHWEST TO AROUND PILOT MOUNTAIN IN NORTH
CAROLINA...AND WEST TO THE GRAYSON HIGHLANDS OF SOUTHWEST
VIRGINIA. ALSO...ANOTHER GENEROUS REGION OF PRECIPITATION WAS
MOVING THROUGH ROCKBRIDGE COUNTY VA...AND THERE WAS ANOTHER ONE
APPROACHING WESTERN GREENBRIER COUNTY AND SUMMERS COUNTY IN
SOUTHEAST WEST VIRGINIA. AS WE PROGRESS INTO THE LATE EVENING AND
TOWARDS MIDNIGHT....FORECAST CHANGES WERE A LITTLE MORE EXPANSIVE.
BASED UPON THE LATEST HRRR AND RNK WRF. THE FORECAST WILL NOW
REFLECT LITTLE OR NO COVERAGE OF PRECIPITATION OUTSIDE SOUTHEAST
WEST VIRGINIA AND NEIGHBORING PORTIONS OF SOUTHWEST VIRGINIA ONCE
WE REACH THAT TIME TONIGHT.
AS OF 330 PM EDT MONDAY...
PWATS 2-3 STANDARD DEVIATIONS ABOVE NORMAL WILL HELP FUEL
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS THIS EVENING.
THE AIRMASS IS UNSEASONABLY JUICY BUT LACK OF ANY GOOD DYNAMICS
SHOULD KEEP ACTIVITY UNORGANIZED. NEVER THE LESS...SLOW MOVEMENT
WILL YIELD HEAVY DOWNPOURS FOR ANY PASSING SHOWER/STORM.
FORECAST AREA REMAINS UNDERNEATH A VERY SHARP UPPER LEVEL
RIDGE...WHICH IS PROMOTING VERY LIGHT STEERING WINDS...0-8KM MEAN
WIND OF ONLY 11 KTS...FROM 290 DEGREES. THIS UPPER RIDGE IS
EXPECTED TO WEAKEN AS WE TRANSITION THROUGH THE NEXT 12-18
HOURS...AS LOW PRESSURE MOVES ACROSS THE GREAT LAKES AND INTO
ONTARIO CANADA. AT THE SURFACE...A COLD FRONT WILL TRAIL SOUTH
FROM THE LOW...CROSSING THE OHIO VALLEY TONIGHT. AS THE FRONT
APPROACHES...IT WILL FOCUS THE DEEPER MOISTURE FROM THE OH/TN
VALLEYS INTO THE WEST SIDE OF THE APPALACHIANS. THIS SQUEEZE PLAY
OF DEEPER MOISTURE IN ADDITION TO LINGERING INSTABILITY OVER THE
MOUNTAINS WILL RESULT IN GOOD COVERAGE OF SHOWER ACTIVITY THROUGH
THIS EVENING.
COVERAGE AND INTENSITY OF SHOWER AND THUNDERSTORM ACTIVITY WILL
DECREASE WITH THE LOSS OF DAYTIME HEATING. HOWEVER...WITH THE
COLD FRONT CONTINUING ITS APPROACH OVERNIGHT...SHOWER THREAT WILL
NOT SUBSIDE ALTOGETHER. MOISTURE TRANSPORT AND CONVERGENCE PER
SOUTHWEST WIND FLOW AHEAD OF THE FRONT WILL CONTINUE TO GENERATE
ACTIVITY INTO THE LATE NIGHT.
SURFACE FRONT IS EXPECTED TO REACH THE WESTERN SLOPES OF THE
APPALACHIANS BY DAYBREAK TUESDAY...THEN MOVE OVER AND EAST OF THE
MTNS MID-DAY...CLEARING THE CWA BY TUESDAY EVENING. WILL MAINTAIN
THREAT FOR SHOWERS UNTIL THE PASSAGE OF THE FRONT...FOLLOWED BY
CLEARING AND DRYING WITH FROPA.
MET/MAV TEMPERATURE GUIDANCE LOOKS GOOD...AND USED A BLEND FOR
TONIGHT`S LOWS AND TUESDAYS HIGHS...READINGS REMAINING QUITE MILD
TONIGHT...AOA 60 FOR LOWS...FOLLOWED BY ANOTHER WARM DAY TUESDAY
WITH HIGHS RANGING IN THE 70S MTNS TO THE 80S IN THE LOWER
ELEVATIONS.
ANY SIGNIFICANT COOLING/DRYING WILL NOT TAKE PLACE UNTIL WE CHANGE
AIRMASSES LATER TUESDAY...BECOMING NOTICEABLE ONCE THE SUN GOES
DOWN TUESDAY EVENING.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 300 PM EDT MONDAY...
ANY LINGERING CONVECTION IN THE FAR SOUTHEAST PORTIONS OF FORECAST
AREA WILL TAPER OFF BY 06Z WEDNESDAY. LOW TEMPERATURES TUESDAY NIGHT
WILL RANGE FROM THE UPPER 40S IN THE NORTHWEST MOUNTAINS TO
THE LOWER 60S IN THE PIEDMONT.
HIGH PRESSURE IN THE MIDWEST WILL RIDGE SOUTHEAST INTO OUR AREA FOR
WEDNESDAY PROVIDING A BREAK FROM THE ACTIVE CONVECTION. THE COOLER
HIGH TEMPERATURES ON WEDNESDAY WILL ALSO BE A WELCOME CHANGE WITH
READINGS FROM THE LOWER 60S IN THE NORTHWEST MOUNTAINS TO THE MID
80S IN THE PIEDMONT. WITH A WEAK SHORTWAVE ROTATING EAST ACROSS THE
REGION WEDNESDAY NIGHT...ALLOW FOR SOME LIGHT POPS IN THE WEST.
LOW TEMPERATURES WEDNESDAY NIGHT WILL VARY FROM THE UPPER 40S IN
THE WEST TO THE UPPER 50S IN THE EAST.
THURSDAYS FORECAST REMAINS A CHALLENGE WITH THE LATEST MODEL RUNS
ALL DEPICT A STRONGER SHORTWAVE TRACKING ACROSS THE AREA...BUT WITH
WIDELY VARYING DEGREES OF INTENSITY AND RESULTANT
MOISTURE/PRECIPITATION. WITH CAUTION...ELECTED TO USE A BLEND OF
SUPERBLEND AND HPCGUIDE WITH SCATTERED POPS FOR THURSDAY. HIGH
TEMPERATURES THURSDAY WILL WARM TO AROUND 60 DEGREES IN THE
NORTHWEST TO AROUND 80 DEGREES ALONG THE SOUTHERN BLUE RIDGE.
SHORTWAVE WILL EXIT TO THE SOUTHEAST THURSDAY NIGHT AS SFC HIGH
PRESSURE SLIDES FROM THE PLAINS TO THE GREAT LAKES. OVERALL...THE
AIRMASS APPEARS TO BE TOO STABLE AND DRY IN THE LOWER LEVELS TO
SUPPORT MUCH THUNDER WITH THIS EVENT. HOWEVER...A NOSE OF
INSTABILITY SUPPORT ISOLATED THUNDERSTORM ACROSS SOUTHERN PORTIONS
OF FORECAST AREA. DIURNAL CONVECTION TAPERS OFF QUICKLY THURSDAY
NIGHT. LOW TEMPERATURES THURSDAY NIGHT WILL GENERALLY VARY FROM THE
UPPER 40S IN THE MOUNTAINS TO THE UPPER 50S IN THE PIEDMONT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 300 PM EDT MONDAY...
MOISTURE...WARMTH...AND HUMIDITY ARE POISED TO RETURN BY EARLY NEXT
WEEK AS YET ANOTHER DEEP UPPER LOW BUILDS INTO THE SOUTHWEST UNITED
STATE...THE NORTHEAST TROUGH PUSHES EASTWARD INTO THE NORTHERN
ATLANTIC...AND AN ELONGATED RIDGE BETWEEN THESE TWO FEATURES DRIFTS
INTO OUR REGION. HIGH TEMPERATURES FRIDAY WARM INTO THE MID 60S IN
THE MOUNTAINS TO THE MID 70S IN THE PIEDMONT. LOW TEMPERATURES WILL
DROP INTO THE MID 40S TO THE 50S IN GENERAL.
ON SATURDAY...CANADIAN HIGH PRESSURE SHIFTS OFF THE MID-ATLANTIC
COAST...AS FRONTAL BOUNDARY IS CENTRAL U.S. LIFTS NORTHEAST. KEPT
SATURDAY DRY...WITH HIGH TEMPERATURES RANGING FROM THE MID 60S IN
THE NORTHWEST MOUNTAINS TO THE UPPER 70S IN THE PIEDMONT.
AS THE HIGH CENTER MOVES EAST...AN EAST TO SOUTHEAST RETURN FLOW ON
THE BACKSIDE MAY DEVELOP A WEDGE ACROSS THE REGION OVER THE WEEKEND.
WITH THE POTENTIAL OF OVERRUNNING PRECIPITATION DEVELOPING FROM THE
WEST. ADDED A SLIGHT CHANCE OF SHOWERS IN THE NORTHWEST MOUNTAINS OF
NORTH CAROLINA. MODERATED LOW TEMPERATURES SATURDAY NIGHT WITH
VALUES MAINLY IN THE 50S...WITH INCREASED CLOUD COVER. SCATTERED
SHOWERS CONTINUED ON SUNDAY WITH THE BEST CHANCES IN THE NORTHWEST.
THE UPPER RIDGE WILL SHIFT SOUTHEAST BY MONDAY...ALLOWING AN ACTIVE
BAROCLINIC ZONE TO SHIFT SOUTH AND EAST INTO THE REGION FROM THE
OH/TN VALLEY. CONTINUED THE POTENTIAL FOR SCATTERED CONVECTION ON
TUESDAY.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AS OF 200 PM EDT MONDAY...
A VERY MOIST AIR MASS REMAINS ACROSS THE REGION STUCK UNDER AN
UPPER RIDGE AS THE PAST SEVERAL DAYS. HOWEVER...THE PATTERN IS
FINALLY ABOUT TO CHANGE. THE UPPER LOW THAT HAS PLAGUED THE
CENTRAL U.S. THE PAST SEVERAL DAYS IS SHEARING OUT AND MOVING
TOWARD THE GREAT LAKES WHERE IT WILL AID IN THE DEVELOPMENT OF A
DEEP UPPER LOW ACROSS SOUTHEAST CANADA BY MIDWEEK. THIS WILL PUSH
A FRONT INTO OUR REGION BY EARLY TUESDAY...THEN EAST OF THE REGION
BY TUE EVENING.
FOR THIS AFTERNOON AND EVENING...SCATTERED TO NUMEROUS SHOWERS
AND THUNDERSTORMS ARE EXPECTED IN ADVANCE OF THE UPPER
TROUGH/FRONT. THE ACTIVITY WILL EXTEND FROM THE OH/TN VALLEYS
EASTWARD INTO THE MID ATLANTIC...AND FARTHER EAST INTO THE
PIEDMONT AS COMPARED TO THE PAST FEW AFTERNOONS. DURING THE
AFTERNOON/EVENING...THUNDERSTORMS SHOULD BE MOST NUMEROUS WEST OF
THE BLUE RIDGE...SOME WITH LOCALLY HEAVY RAINFALL. THE STRONGER
STORMS WILL CONTAIN LOCALIZED OUTFLOW WINDS OF 25-30KTS IN
ADDITION TO MVFR CIGS AND BRIEF PERIODS OF MVFR-IFR VSBYS. LACK OF
ORGANIZATION MAKES IT DIFFICULT TO PINPOINT TIMING AT ANY OF THE
TERMINALS...ESP THOSE EAST OF THE BLUE RIDGE. AS SUCH...WILL
CONTINUE TO MENTION VCNTY SHRA/TSRA AND AMEND TAFS PER RADAR
TRENDS.
COVERAGE OF THE SHOWERS/THUNDERSTORMS WILL DECREASE AFTER
SUNSET...BUT GIVEN THE SYNOPTIC PATTERN WOULD EXPECT SOME ACTIVITY
TO LINGER ALL NIGHT ACROSS MUCH OF THE CWA. WITH WINDS BECOMING
NW...UPSLOPE MVFR CIGS APPEAR LIKELY ACROSS EASTERN WV INTO FAR
SOUTHWEST VA...WITH MODELS SUGGESTING PERIOD OF IFR CIGS PRIOR TO
DAYBREAK TUESDAY AT KBLF/KLWB. MVFR VSBYS WILL ALSO PREVAIL IN
MANY AREAS OVERNIGHT IN A NEAR SATURATED BOUNDARY LAYER WITH
MOIST/WET GROUND AND LIGHT WSW-WNW WINDS.
ANY LOW CIG/VSBY ELEMENTS SHOULD QUICKLY IMPROVE AFTER 13Z/9AM
TUESDAY WITH RETURN OF VFR FOR THE AFTERNOON. SURFACE FRONT WILL
PASS THROUGH ALL TERMINALS TUESDAY WITH SKIES CLEARING AND WINDS
BECOMING NORTHWEST 6 TO 12 KTS.
EXTENDED AVIATION DISCUSSION...
DRIER/COOLER CONDITIONS ARE EXPECTED TUESDAY NIGHT AND WEDNESDAY.
AN UPPER DISTURBANCE WILL LIKELY BRING SOME MVFR CIGS AND -SHRA
BACK INTO THE AREA THU...MOVING OUT FRIDAY WITH VFR CONDITIONS
RETURNING FRI-SAT.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...PM
NEAR TERM...DS/PM
SHORT TERM...KK
LONG TERM...KK
AVIATION...PM
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
550 PM CDT MON MAY 18 2015
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 235 PM CDT MON MAY 18 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW OCCLUDED
LOW PRESSURE MOVING EAST OVER WESTERN LAKE SUPERIOR. A VERY CHILLY
AIRMASS FOR THIS TIME OF THE YEAR IS WRAPPING AROUND THE LOW AND
GRADUALLY MOVING EAST OVER THE WESTERN HALF OF WISCONSIN. THE LOW
STRATUS HAS MOVED VERY LITTLE EASTWARD SO FAR TODAY...BUT SHOULD
GAIN SOME MOMENTUM THROUGH THE AFTERNOON AS THE COLDER AIR AT 850MB
OVER TAKES IT. PLENTY OF OBS ARE REPORTING LIGHT RAIN/DRIZZLE...AND
EVEN A FEW FLAKES UPSTREAM OVER NORTHWEST WISCONSIN AND NORTHERN
MINNESOTA. AS THE COLDER AIR AND LIGHT PRECIP SPREAD ACROSS THE
REGION...TEMPS AND PRECIP TRENDS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...OCCLUDED LOW PRESSURE WILL MOVE EAST OVER LAKE SUPERIOR
AND NORTHERN ONTARIO AND WEAKEN AT THE SAME TIME. AS WINDS SHIFT TO
THE NORTHWEST...COLD ADVECTION WILL CONTINUE ACROSS THE STATE
THROUGH THE NIGHT...DROPPING 850MB TEMPS TO AROUND -8C TO -10C.
DEEPER MOISTURE WILL BE ROTATING ACROSS NORTHERN WISCONSIN AND
COMBINED WITH UPSLOPE FLOW OFF LAKE SUPERIOR AND UNSTABLE
CONDITIONS...SHOULD SEE PERIODS OF LIGHT RAIN/DRIZZLE...MIXED WITH
SNOW AT TIMES. TEMPERATURES WILL BE FALLING INTO THE 30-32 DEGREE
RANGE OVER NORTHERN WISCONSIN FOR A FEW HOURS LATE TONIGHT. BUT
AREAS OVER THE UPPER PENINSULA AND NORTHWEST WISCONSIN HAVE NOT
OFFICIALLY STARTED THEIR GROWING SEASONS...SO WILL HIGHLIGHT THE
COLD IN A SPECIAL WEATHER STATEMENT. ELSEWHERE...LOOK FOR A CLOUDY
AND BLUSTERY NIGHT.
TUESDAY...THERMAL TROUGHING AND FLOW OFF LAKE SUPERIOR ARGUE FOR A
CLOUDY/MOSTLY CLOUDY START TO THE DAY. BUT SHOULD SEE CLOUDS
GRADUALLY ERODE FROM SOUTHWEST THROUGH NORTHEAST THROUGH THE DAY AS
CYCLONIC FLOW ABATES AND LOW LEVEL TEMPS MODERATE. LOWERED MAX
TEMPS A DEGREE...AND WENT WITH HIGHS RANGING FROM THE MID 40S NORTH
TO MID 50S SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 235 PM CDT MON MAY 18 2015
FROST/FREEZE HEADLINE POTENTIAL TUESDAY NIGHT AND WEDNESDAY NIGHT...
AND PCPN TRENDS FOR THE MEMORIAL DAY WEEKEND...ARE THE MAIN FCST
CONCERNS.
CANADIAN HIGH PRESSURE WILL BE RIDGED OVER THE WSTRN GREAT LAKES
ON TUESDAY NIGHT...AND WILL BRING LIGHT WINDS TO THE FORECAST AREA.
EXPECT SKIES TO BE MOSTLY CLEAR OVER NORTHERN WI...LEADING TO
WIDESPREAD SUB-FREEZING TEMPERATURES. AVERAGE MIXING RATIOS OF
2.5 TO 3 G/KG SUPPORT THE POTENTIAL FOR MIN TEMPS AS COLD AS
20 TO 25 AT THE CLIMATOLOGICALLY FAVORED COLD SPOTS. HIGH CLOUDS
ARE EXPECTED TO INCREASE OVER C/EC WI...ON THE ANTICYCLONIC SHEAR
SIDE...AND WITHIN THE RRQ...OF A STRONG UPPER JET STREAK. WHILE
THIS LIKELY WILL NOT PREVENT FROST DEVELOPMENT IN OUR SOUTHERN
COUNTIES...IT SHOULD AT LEAST KEEP MOST PLACES ABOVE FREEZING.
WILL NOT ISSUE ANY HEADLINES WITH THIS FORECAST PACKAGE...BUT
FROST/FREEZE HEADLINES APPEAR IMMINENT.
THE POTENTIAL FOR FROST WILL CONTINUE INTO WEDNESDAY NIGHT...
BUT SHOULD SHIFT TO MAINLY NORTHERN WI...WHERE MIN TEMPS ARE
EXPECTED TO DROP INTO THE LOWER TO MIDDLE 30S.
A WEAK BACK DOOR COLD FRONT IS EXPECTED TO DROP SOUTH THROUGH
THE REGION SOMETIME DURING THE WEDS NGT TO THU NGT PERIOD. THE
GFS IS FOCUSING ON WEDS NGT/THU...WHILE THE ECMWF IS SLOWER
AND BRINGS THE FRONT THROUGH THU AND EARLY THU NGT. A VERY
DRY AIR MASS SHOULD PRECLUDE ANY PCPN DEVELOPMENT.
CANADIAN HIGH PRESSURE WILL RETURN TO THE WSTRN GREAT LAKES
FRIDAY...AND SHOULD HOLD ANY PCPN AT BAY THROUGH AT LEAST
SATURDAY.
A COLD FRONT/INVERTED SFC TROF AND UPPER TROF WILL IMPACT THE
REGION FOR THE LATTER HALF OF THE MEMORIAL DAY WEEKEND...BUT
TIMING DIFFERENCES ARE SIGNIFICANT BETWEEN THE MODELS. THE GFS
HAS PCPN OVER THE REGION FROM SAT NGT THROUGH MONDAY...WITH THE
HEAVIEST QPF FCST ON SUNDAY. THE ECMWF IS SLOWER...AND FOCUSES
MOST OF THE PCPN DURING THE SUNDAY NIGHT AND MONDAY PERIODS.
DUE TO THE TIMING DIFFERENCES...HAVE BACKED OFF ON LIKELY POPS
FOR ANY SPECIFIC PERIOD...BUT OVERALL TRENDS SUPPORT AT LEAST
A PERIOD OR TWO OF MODERATE RAINFALL.
SLIGHTLY BLO NORMAL TEMPERATURES ARE EXPECTED AT THE BEGINNING
AND END OF THE EXTENDED PERIOD...WITH NEAR NORMAL READINGS FOR
THE REST OF THE DAYS.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 548 PM CDT MON MAY 18 2015
A MUCH COLDER AIR MASS WILL POUR ACROSS THE TAF SITES OVER THE
NEXT 24 HOURS. OCCASIONAL RAIN SHOWERS...DRIZZLE AND A SNOW SHOWER
OR TWO ARE LIKELY ACROSS NORTH-CENTRAL WISCONSIN TONIGHT AS DEEPER
MOISTURE MOVES OVERHEAD. OTHERWISE...WINDS WILL VEER TO THE
NORTHWEST TONIGHT AND REMAIN GUSTY. BROKEN MVFR CIGS WILL SPREAD
EAST INTO EASTERN WISCONSIN LATER THIS EVENING AND HANG AROUND
INTO TUESDAY MORNING. COOL DRY HIGH PRESSURE SETTLING INTO THE
GREAT LAKES REGION WILL PRODUCE VFR CIGS LATER TUESDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......TDH
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 235 PM CDT MON MAY 18 2015
THE LATEST RAP ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW OCCLUDED
LOW PRESSURE MOVING EAST OVER WESTERN LAKE SUPERIOR. A VERY CHILLY
AIRMASS FOR THIS TIME OF THE YEAR IS WRAPPING AROUND THE LOW AND
GRADUALLY MOVING EAST OVER THE WESTERN HALF OF WISCONSIN. THE LOW
STRATUS HAS MOVED VERY LITTLE EASTWARD SO FAR TODAY...BUT SHOULD
GAIN SOME MOMENTUM THROUGH THE AFTERNOON AS THE COLDER AIR AT 850MB
OVER TAKES IT. PLENTY OF OBS ARE REPORTING LIGHT RAIN/DRIZZLE...AND
EVEN A FEW FLAKES UPSTREAM OVER NORTHWEST WISCONSIN AND NORTHERN
MINNESOTA. AS THE COLDER AIR AND LIGHT PRECIP SPREAD ACROSS THE
REGION...TEMPS AND PRECIP TRENDS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...OCCLUDED LOW PRESSURE WILL MOVE EAST OVER LAKE SUPERIOR
AND NORTHERN ONTARIO AND WEAKEN AT THE SAME TIME. AS WINDS SHIFT TO
THE NORTHWEST...COLD ADVECTION WILL CONTINUE ACROSS THE STATE
THROUGH THE NIGHT...DROPPING 850MB TEMPS TO AROUND -8C TO -10C.
DEEPER MOISTURE WILL BE ROTATING ACROSS NORTHERN WISCONSIN AND
COMBINED WITH UPSLOPE FLOW OFF LAKE SUPERIOR AND UNSTABLE
CONDITIONS...SHOULD SEE PERIODS OF LIGHT RAIN/DRIZZLE...MIXED WITH
SNOW AT TIMES. TEMPERATURES WILL BE FALLING INTO THE 30-32 DEGREE
RANGE OVER NORTHERN WISCONSIN FOR A FEW HOURS LATE TONIGHT. BUT
AREAS OVER THE UPPER PENINSULA AND NORTHWEST WISCONSIN HAVE NOT
OFFICIALLY STARTED THEIR GROWING SEASONS...SO WILL HIGHLIGHT THE
COLD IN A SPECIAL WEATHER STATEMENT. ELSEWHERE...LOOK FOR A CLOUDY
AND BLUSTERY NIGHT.
TUESDAY...THERMAL TROUGHING AND FLOW OFF LAKE SUPERIOR ARGUE FOR A
CLOUDY/MOSTLY CLOUDY START TO THE DAY. BUT SHOULD SEE CLOUDS
GRADUALLY ERODE FROM SOUTHWEST THROUGH NORTHEAST THROUGH THE DAY AS
CYCLONIC FLOW ABATES AND LOW LEVEL TEMPS MODERATE. LOWERED MAX
TEMPS A DEGREE...AND WENT WITH HIGHS RANGING FROM THE MID 40S NORTH
TO MID 50S SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 235 PM CDT MON MAY 18 2015
FROST/FREEZE HEADLINE POTENTIAL TUESDAY NIGHT AND WEDNESDAY NIGHT...
AND PCPN TRENDS FOR THE MEMORIAL DAY WEEKEND...ARE THE MAIN FCST
CONCERNS.
CANADIAN HIGH PRESSURE WILL BE RIDGED OVER THE WSTRN GREAT LAKES
ON TUESDAY NIGHT...AND WILL BRING LIGHT WINDS TO THE FORECAST AREA.
EXPECT SKIES TO BE MOSTLY CLEAR OVER NORTHERN WI...LEADING TO
WIDESPREAD SUB-FREEZING TEMPERATURES. AVERAGE MIXING RATIOS OF
2.5 TO 3 G/KG SUPPORT THE POTENTIAL FOR MIN TEMPS AS COLD AS
20 TO 25 AT THE CLIMATOLOGICALLY FAVORED COLD SPOTS. HIGH CLOUDS
ARE EXPECTED TO INCREASE OVER C/EC WI...ON THE ANTICYCLONIC SHEAR
SIDE...AND WITHIN THE RRQ...OF A STRONG UPPER JET STREAK. WHILE
THIS LIKELY WILL NOT PREVENT FROST DEVELOPMENT IN OUR SOUTHERN
COUNTIES...IT SHOULD AT LEAST KEEP MOST PLACES ABOVE FREEZING.
WILL NOT ISSUE ANY HEADLINES WITH THIS FORECAST PACKAGE...BUT
FROST/FREEZE HEADLINES APPEAR IMMINENT.
THE POTENTIAL FOR FROST WILL CONTINUE INTO WEDNESDAY NIGHT...
BUT SHOULD SHIFT TO MAINLY NORTHERN WI...WHERE MIN TEMPS ARE
EXPECTED TO DROP INTO THE LOWER TO MIDDLE 30S.
A WEAK BACK DOOR COLD FRONT IS EXPECTED TO DROP SOUTH THROUGH
THE REGION SOMETIME DURING THE WEDS NGT TO THU NGT PERIOD. THE
GFS IS FOCUSING ON WEDS NGT/THU...WHILE THE ECMWF IS SLOWER
AND BRINGS THE FRONT THROUGH THU AND EARLY THU NGT. A VERY
DRY AIR MASS SHOULD PRECLUDE ANY PCPN DEVELOPMENT.
CANADIAN HIGH PRESSURE WILL RETURN TO THE WSTRN GREAT LAKES
FRIDAY...AND SHOULD HOLD ANY PCPN AT BAY THROUGH AT LEAST
SATURDAY.
A COLD FRONT/INVERTED SFC TROF AND UPPER TROF WILL IMPACT THE
REGION FOR THE LATTER HALF OF THE MEMORIAL DAY WEEKEND...BUT
TIMING DIFFERENCES ARE SIGNIFICANT BETWEEN THE MODELS. THE GFS
HAS PCPN OVER THE REGION FROM SAT NGT THROUGH MONDAY...WITH THE
HEAVIEST QPF FCST ON SUNDAY. THE ECMWF IS SLOWER...AND FOCUSES
MOST OF THE PCPN DURING THE SUNDAY NIGHT AND MONDAY PERIODS.
DUE TO THE TIMING DIFFERENCES...HAVE BACKED OFF ON LIKELY POPS
FOR ANY SPECIFIC PERIOD...BUT OVERALL TRENDS SUPPORT AT LEAST
A PERIOD OR TWO OF MODERATE RAINFALL.
SLIGHTLY BLO NORMAL TEMPERATURES ARE EXPECTED AT THE BEGINNING
AND END OF THE EXTENDED PERIOD...WITH NEAR NORMAL READINGS FOR
THE REST OF THE DAYS.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1207 PM CDT MON MAY 18 2015
A MUCH COLDER AIRMASS WILL FILTER ACROSS THE TAF SITES OVER THE
NEXT 24 HOURS. OCCASIONAL RAIN SHOWERS...DRIZZLE...AND A SNOW
SHOWER OR TWO ARE LIKELY ACROSS NORTH-CENTRAL WISCONSIN TONIGHT AS
DEEPER MOISTURE MOVES OVERHEAD. OTHERWISE...WINDS WILL VEER TO THE
NORTHWEST TONIGHT AND REMAIN GUSTY. BROKEN MVFR CIGS WILL SPREAD
EAST INTO EASTERN WISCONSIN THIS EVENING AND LOOK TO HANG AROUND
THROUGH THE END OF THE TAF PERIOD.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......MPC