Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/21/13
AREA FORECAST DISCUSSION
NWS MIAMI FL
851 PM EDT SAT APR 20 2013
.UPDATE...
CONVECTION ENDED FOR THE EAST COAST EARLIER THIS EVENING. STORMS
RAPIDLY INTENSIFIED ONCE THEY HIT THE EAST COAST SEA BREEZE...WITH
A PEAK WIND GUST OF 72 MPH REPORTED NEAR HOLLYWOOD. TRANSVERSE
BANDS WERE EVIDENT IN VISIBLE SATELLITE IMAGERY EARLIER AS THE
NOSE OF THE SUBTROPICAL JET MOVED INTO THE GULF COAST. SHOWERS AND
EMBEDDED THUNDERSTORMS CONTINUE TO DEVELOP ALONG THE GULF
COAST...BUT THESE ARE EXPECTED TO BEGIN TO DIMINISH WITH THE LOSS
OF DAYTIME HEATING.
THE FRONTAL BOUNDARY MOVED INTO DEEP SOUTH FLORIDA BEFORE
STALLING LATE THIS AFTERNOON. IT IS BEGINNING TO WASH OUT
NOW...BUT A LOW LEVEL TROUGH WILL REMAIN ACROSS OR NEAR THE REGION
THROUGH MONDAY. THE UPPER LEVEL TROUGH WAS ACROSS THE GULF...BUT
THIS WILL MOVE EAST ON SUNDAY...WITH COOLER TEMPERATURES ALOFT
OVER SOUTH FLORIDA.
OVERNIGHT TONIGHT...SCATTERED SHOWERS AND FEW THUNDERSTORMS MAY
DEVELOP OVER THE GULF WATERS AHEAD OF THE UPPER TROUGH AND THE
SUBTROPICAL JET. UPPER LEVEL IMPULSES ARE FORECAST TO MOVE ACROSS
THE EASTERN GULF AND ACROSS CENTRAL/SOUTH FLORIDA SUNDAY AFTERNOON
INTO SUNDAY NIGHT...WITH STRONG TO POSSIBLY A COUPLE LOW END
SEVERE STORMS POSSIBLE. STORM MOTION WILL BE ALMOST NIL...WITH
STORM MOVEMENT DICTATED MOSTLY BY OUTFLOW AND SEA BREEZE
BOUNDARIES.
&&
.PREV DISCUSSION... /ISSUED 814 PM EDT SAT APR 20 2013/
AVIATION...
ALTHOUGH THE STRONG TO SEVERE THUNDERSTORMS THAT DEVELOPED EARLIER
OVER THE EAST COAST HAVE SHIFTED EAST OVER THE ATLANTIC WATERS AND
WEAKENED...ADDITIONAL SHOWERS AND STORMS HAVE DEVELOPED JUST
INLAND OF THE APF TERMINAL THIS EVENING. THIS ACTIVITY SHOULD
REMAIN JUST INLAND OF THE TERMINAL THROUGH THE MID EVENING HOURS
BEFORE TRENDING DOWN. OVERNIGHT...ANOTHER WEAK IMPULSE ALOFT
CURRENTLY LOCATED WEST OF THE FL PENINSULA OVER THE EASTERN GULF
COULD GENERATE ADDITIONAL SHOWERS AND STORMS LATER TONIGHT INTO
SUNDAY MORNING OVER THE GULF WATERS AND COASTAL AREAS INCLUDING
APF. HOWEVER...CONFIDENCE IS LOW AT THIS TIME DUE TO MODEL
DIFFERENCES BETWEEN THE HRRR AND WRF OUTPUT. AS A RESULT...WE WILL
INCLUDE MAINLY VCSH OVERNIGHT AND MONITOR THE ACTIVITY OVER THE
GULF FOR THE 06Z PACKAGE. LATER TOMORROW...MEAN LOW-LEVEL FLOW
WILL REMAIN LIGHT OUT OF THE SW. THIS FLOW COMBINED WITH WEAK
UPPER PULSES PASSING OVERHEAD AND THE EAST COAST SEA BREEZES WILL
BE ENOUGH TO SUPPORT THE POTENTIAL FOR ANOTHER ROUND OF
STRONG/SEVERE THUNDERSTORMS THROUGH THE AFTERNOON PERIOD TOMORROW
ALONG THE EAST COAST.
PREV DISCUSSION... /ISSUED 217 PM EDT SAT APR 20 2013/
DISCUSSION...
SATURDAY THROUGH MONDAY...
IN THE SHORT TERM FOR THIS AFTERNOON AND EVENING THERE IS NOT MUCH
CHANGE FROM THE PREVIOUS THINKING. THE SHOWERS AND THUNDERSTORMS
OVER THE ATLANTIC WATERS HAVE DIMINISHED IN COVERAGE BUT A FEW
SHOWERS ARE BEGINNING TO DEVELOP ALONG THE SEA BREEZE EXTENDING FROM
SOUTH MIAMI-DADE TO COASTAL PALM BEACH COUNTY AS WELL AS WEST OF
LAKE OKEECHOBEE ASSOCIATED WITH THE FRONT ITSELF. THIS PATTERN IS
CONSISTENT WITH THE FORECAST OF HIGH RESOLUTION MODELS FOR THIS
AFTERNOON AND EVENING. FAVORING FACTORS FOR THE FORMATION OF SHOWERS
AND THUNDERSTORMS ALONG THE EAST COAST ARE: THE WEAK SOUTHWESTERLY
FLOW AND THE TROUGH OF LOW PRESSURE NEAR THE FLORIDA EAST COAST. THE
LIMITING FACTORS ARE THE WARM 500 MB TEMPERATURES AND THE CAP AROUND
15KFT. IT IS POSSIBLE THAT ONCE THE ACTIVITY ALONG THE SEA BREEZE
REACHES THE CAP IT COULD DIMINISH IN INTENSITY BUT STILL PRODUCE
HEAVY RAINS, GUSTY WINDS, AND LIGHTNING. IN OTHER WORDS, IT COULD
START ACTIVE IN THE NEXT FEW HOURS AND THEN WEAKEN A BIT AS THE
STORMS START REACHING THE CAP. THE ADVANCE OF THE FRONT IS ALSO A
FAVORABLE FACTOR THAT IT COULD BECOME MORE IMPORTANT AS THE DAY
PROGRESSES. THE STEERING FLOW WILL MOVE STORMS GENERALLY FROM WEST
TO EAST. THIS WILL INCREASE THE POTENTIAL FOR THUNDERSTORMS FOR
THE EAST COAST.
THE CURRENT 500 MB PATTERN SHOWS A TROUGH OF LOW PRESSURE OVER THE
EASTERN AND CENTRAL US AND A STRONG BLOCKING RIDGE OF HIGH PRESSURE
OVER THE WESTERN ATLANTIC. AS THE HIGH CONTINUES TO MOVE FURTHER
EAST COOLER 500 MB TEMPERATURES WILL SPREAD OVER SOUTH FLORIDA ON
SUNDAY. THIS IS EXPECTED TO INCREASE THE POTENTIAL FOR STRONG OR
EVEN SEVERE STORMS ON SUNDAY IF HEATING IS FAVORABLE.
LONG TERM /TUESDAY THROUGH FRIDAY/...
BEHIND THE SURFACE TROUGH...A MORE TYPICAL SPRING WEATHER REGIME
WILL TAKE HOLD OVER FLORIDA...WITH EASTERLY LOW-LEVEL FLOW AND
HIGH PRESSURE BUILDING BOTH NEAR SURFACE AND ALOFT. ISOLATED
MAINLY DIURNAL SHOWERS ARE EXPECTED...WITH PARTLY TO MOSTLY SUNNY
SKIES AND TEMPERATURES REMAINING SLIGHTLY ABOVE AVERAGE.
AVIATION...ISSUED AT 147 PM EDT SAT APR 20 2013...
SHOWERS AND THUNDERSTORMS ARE BEGINNING TO SAG INTO THE NORTHWEST
INTERIOR AREAS. WITH AN ESTABLISHED GULF COAST SEA BREEZE...THIS
ACTIVITY SHOULD CONTINUE TO PUSH TO THE EAST. ADDITIONAL
CONVECTION WILL ALSO BE POSSIBLE ACROSS THE EAST COAST TERMINALS
OVER THE NEXT FEW HOURS OF PEAK HEATING. KEPT TEMPO GROUPS AT ALL
EAST COAST SITES FROM 20Z-23Z. WILL AMEND IF NECESSARY.
MARINE...
LONG-FUSED ADVISORIES AND WARNINGS ARE NOT EXPECTED THIS WEEKEND
OR NEXT WEEK OVER THE WATERS. LOCALLY HIGH WAVES AND WINDS CAN BE
EXPECTED IN SCATTERED TO NUMEROUS THUNDERSTORMS TODAY THROUGH
MONDAY...AND SPECIAL MARINE WARNINGS MAY BE ISSUED FROM TIME TO
TIME.
FIRE WEATHER...
MINIMUM RELATIVE HUMIDITY VALUES WILL BE ABOVE 50 PERCENT THIS
WEEKEND AND EARLY NEXT WEEK...AS MOIST ATMOSPHERE CONTRIBUTES TO
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. WINDS WILL MAINLY
SOUTH TODAY...BUT TRANSITION TO THE NORTHEAST TONIGHT AS COLD FRONT
MOVES IN. LOW WIND SPEEDS ARE EXPECTED OUTSIDE OF SHOWERS AND
THUNDERSTORMS.
PREV DISCUSSION... /ISSUED 947 AM EDT SAT APR 20 2013/
UPDATE...
SHOWERS AND THUNDERSTORMS OVER THE ATLANTIC WATERS HAVE DEVELOPED
THIS MORNING DUE TO THE CONVERGENCE OF SE FLOW OVER THE BAHAMAS
AND MORE SOUTHERLY FLOW OVER SOUTH FLORIDA. THE 12Z SOUNDING FROM
THIS MORNING SHOWS A CAP AROUND 650 MB ASSOCIATED WITH THE
SUBTROPICAL HIGH PRESSURE OVER THE ATLANTIC AND THE GULF. 500 MB
TEMPERATURES ARE AROUND -6C AND ARE NOT EXPECTED TO COOL BEYOND
-7C THIS AFTERNOON. HOWEVER, THE INFLUENCE OF A COLD FRONT MOVING
SOUTHWARD IS EXPECTED TO INTERACT WITH A WEAK EAST COAST SEA
BREEZE TO TRIGGER SHOWERS AND THUNDERSTORMS, ESPECIALLY IN PALM
BEACH AND BROWARD COUNTIES. SOME STORMS CAN ALSO EXTEND INTO
MIAMI-DADE. FOR THE WEST COAST THERE IS ONLY A SMALL CHANCE OF
THUNDERSTORMS, SINCE MOST OF THE SURFACE TROUGH IS ALIGNED FROM
NORTHEAST TO SOUTHWEST OVER THE ATLANTIC WATERS.
AS MENTIONED IN THE PREVIOUS DISCUSSION THE UPPER LEVEL
TEMPERATURES ARE FORECAST TO COOL ON SUNDAY ALLOWING FOR A GREATER
CHANCE OF THUNDERSTORMS THAN TODAY.
FOR TODAY THE HIGHEST POPS ARE STILL INCLUDED FOR PALM BEACH AND
BROWARD.
PREV DISCUSSION... /ISSUED 725 AM EDT SAT APR 20 2013/
AVIATION...
MOSTLY VFR CONDITIONS WILL OCCUR EARLY IN THE FORECAST ALTHOUGH
THERE COULD BE A BRIEF MVFR CIG AS A FEW SHOWERS MOVE ACROSS SOUTH
FLORIDA. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP BY THIS AFTERNOON AHEAD OF A WEAKENING COLD
FRONT THAT WILL SAG ACROSS THE REGION. THE HRRR INDICATES
CONVECTION TO BEGIN DEVELOPING IN EARNEST BETWEEN 18-20Z WITH THE
STEERING FLOW TAKING THE STORMS TO THE EAST COAST. THEREFORE, HAVE
LEFT TEMPO 18-22Z FOR ALL EAST TERMINALS WITH SOME OF THE ACTIVITY
POSSIBLY PERSISTING BEYOND THIS TIME FRAME. SURFACE WINDS ARE
QUESTIONABLE WITH A SLOW MOVING FRONTAL BOUNDARY BUT GENERALLY
SSW-SSE AHEAD OF THE FRONT AND NE BEHIND THE FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 71 84 70 83 / 20 60 40 60
FORT LAUDERDALE 74 85 72 84 / 20 60 40 60
MIAMI 73 86 73 85 / 20 50 40 60
NAPLES 69 86 70 84 / 40 40 40 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS MIAMI FL
814 PM EDT SAT APR 20 2013
.AVIATION...
ALTHOUGH THE STRONG TO SEVERE THUNDERSTORMS THAT DEVELOPED EARLIER
OVER THE EAST COAST HAVE SHIFTED EAST OVER THE ATLANTIC WATERS AND
WEAKENED...ADDITIONAL SHOWERS AND STORMS HAVE DEVELOPED JUST
INLAND OF THE APF TERMINAL THIS EVENING. THIS ACTIVITY SHOULD
REMAIN JUST INLAND OF THE TERMINAL THROUGH THE MID EVENING HOURS
BEFORE TRENDING DOWN. OVERNIGHT...ANOTHER WEAK IMPULSE ALOFT
CURRENTLY LOCATED WEST OF THE FL PENINSULA OVER THE EASTERN GULF
COULD GENERATE ADDITIONAL SHOWERS AND STORMS LATER TONIGHT INTO
SUNDAY MORNING OVER THE GULF WATERS AND COASTAL AREAS INCLUDING
APF. HOWEVER...CONFIDENCE IS LOW AT THIS TIME DUE TO MODEL
DIFFERENCES BETWEEN THE HRRR AND WRF OUTPUT. AS A RESULT...WE WILL
INCLUDE MAINLY VCSH OVERNIGHT AND MONITOR THE ACTIVITY OVER THE
GULF FOR THE 06Z PACKAGE. LATER TOMORROW...MEAN LOW-LEVEL FLOW
WILL REMAIN LIGHT OUT OF THE SW. THIS FLOW COMBINED WITH WEAK
UPPER PULSES PASSING OVERHEAD AND THE EAST COAST SEA BREEZES WILL
BE ENOUGH TO SUPPORT THE POTENTIAL FOR ANOTHER ROUND OF
STRONG/SEVERE THUNDERSTORMS THROUGH THE AFTERNOON PERIOD TOMORROW
ALONG THE EAST COAST.
&&
.PREV DISCUSSION... /ISSUED 217 PM EDT SAT APR 20 2013/
DISCUSSION...
SATURDAY THROUGH MONDAY...
IN THE SHORT TERM FOR THIS AFTERNOON AND EVENING THERE IS NOT MUCH
CHANGE FROM THE PREVIOUS THINKING. THE SHOWERS AND THUNDERSTORMS
OVER THE ATLANTIC WATERS HAVE DIMINISHED IN COVERAGE BUT A FEW
SHOWERS ARE BEGINNING TO DEVELOP ALONG THE SEA BREEZE EXTENDING FROM
SOUTH MIAMI-DADE TO COASTAL PALM BEACH COUNTY AS WELL AS WEST OF
LAKE OKEECHOBEE ASSOCIATED WITH THE FRONT ITSELF. THIS PATTERN IS
CONSISTENT WITH THE FORECAST OF HIGH RESOLUTION MODELS FOR THIS
AFTERNOON AND EVENING. FAVORING FACTORS FOR THE FORMATION OF SHOWERS
AND THUNDERSTORMS ALONG THE EAST COAST ARE: THE WEAK SOUTHWESTERLY
FLOW AND THE TROUGH OF LOW PRESSURE NEAR THE FLORIDA EAST COAST. THE
LIMITING FACTORS ARE THE WARM 500 MB TEMPERATURES AND THE CAP AROUND
15KFT. IT IS POSSIBLE THAT ONCE THE ACTIVITY ALONG THE SEA BREEZE
REACHES THE CAP IT COULD DIMINISH IN INTENSITY BUT STILL PRODUCE
HEAVY RAINS, GUSTY WINDS, AND LIGHTNING. IN OTHER WORDS, IT COULD
START ACTIVE IN THE NEXT FEW HOURS AND THEN WEAKEN A BIT AS THE
STORMS START REACHING THE CAP. THE ADVANCE OF THE FRONT IS ALSO A
FAVORABLE FACTOR THAT IT COULD BECOME MORE IMPORTANT AS THE DAY
PROGRESSES. THE STEERING FLOW WILL MOVE STORMS GENERALLY FROM WEST
TO EAST. THIS WILL INCREASE THE POTENTIAL FOR THUNDERSTORMS FOR
THE EAST COAST.
THE CURRENT 500 MB PATTERN SHOWS A TROUGH OF LOW PRESSURE OVER THE
EASTERN AND CENTRAL US AND A STRONG BLOCKING RIDGE OF HIGH PRESSURE
OVER THE WESTERN ATLANTIC. AS THE HIGH CONTINUES TO MOVE FURTHER
EAST COOLER 500 MB TEMPERATURES WILL SPREAD OVER SOUTH FLORIDA ON
SUNDAY. THIS IS EXPECTED TO INCREASE THE POTENTIAL FOR STRONG OR
EVEN SEVERE STORMS ON SUNDAY IF HEATING IS FAVORABLE.
LONG TERM /TUESDAY THROUGH FRIDAY/...
BEHIND THE SURFACE TROUGH...A MORE TYPICAL SPRING WEATHER REGIME
WILL TAKE HOLD OVER FLORIDA...WITH EASTERLY LOW-LEVEL FLOW AND
HIGH PRESSURE BUILDING BOTH NEAR SURFACE AND ALOFT. ISOLATED
MAINLY DIURNAL SHOWERS ARE EXPECTED...WITH PARTLY TO MOSTLY SUNNY
SKIES AND TEMPERATURES REMAINING SLIGHTLY ABOVE AVERAGE.
AVIATION...ISSUED AT 147 PM EDT SAT APR 20 2013...
SHOWERS AND THUNDERSTORMS ARE BEGINNING TO SAG INTO THE NORTHWEST
INTERIOR AREAS. WITH AN ESTABLISHED GULF COAST SEA BREEZE...THIS
ACTIVITY SHOULD CONTINUE TO PUSH TO THE EAST. ADDITIONAL
CONVECTION WILL ALSO BE POSSIBLE ACROSS THE EAST COAST TERMINALS
OVER THE NEXT FEW HOURS OF PEAK HEATING. KEPT TEMPO GROUPS AT ALL
EAST COAST SITES FROM 20Z-23Z. WILL AMEND IF NECESSARY.
MARINE...
LONG-FUSED ADVISORIES AND WARNINGS ARE NOT EXPECTED THIS WEEKEND
OR NEXT WEEK OVER THE WATERS. LOCALLY HIGH WAVES AND WINDS CAN BE
EXPECTED IN SCATTERED TO NUMEROUS THUNDERSTORMS TODAY THROUGH
MONDAY...AND SPECIAL MARINE WARNINGS MAY BE ISSUED FROM TIME TO
TIME.
FIRE WEATHER...
MINIMUM RELATIVE HUMIDITY VALUES WILL BE ABOVE 50 PERCENT THIS
WEEKEND AND EARLY NEXT WEEK...AS MOIST ATMOSPHERE CONTRIBUTES TO
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. WINDS WILL MAINLY
SOUTH TODAY...BUT TRANSITION TO THE NORTHEAST TONIGHT AS COLD FRONT
MOVES IN. LOW WIND SPEEDS ARE EXPECTED OUTSIDE OF SHOWERS AND
THUNDERSTORMS.
PREV DISCUSSION... /ISSUED 947 AM EDT SAT APR 20 2013/
UPDATE...
SHOWERS AND THUNDERSTORMS OVER THE ATLANTIC WATERS HAVE DEVELOPED
THIS MORNING DUE TO THE CONVERGENCE OF SE FLOW OVER THE BAHAMAS
AND MORE SOUTHERLY FLOW OVER SOUTH FLORIDA. THE 12Z SOUNDING FROM
THIS MORNING SHOWS A CAP AROUND 650 MB ASSOCIATED WITH THE
SUBTROPICAL HIGH PRESSURE OVER THE ATLANTIC AND THE GULF. 500 MB
TEMPERATURES ARE AROUND -6C AND ARE NOT EXPECTED TO COOL BEYOND
-7C THIS AFTERNOON. HOWEVER, THE INFLUENCE OF A COLD FRONT MOVING
SOUTHWARD IS EXPECTED TO INTERACT WITH A WEAK EAST COAST SEA
BREEZE TO TRIGGER SHOWERS AND THUNDERSTORMS, ESPECIALLY IN PALM
BEACH AND BROWARD COUNTIES. SOME STORMS CAN ALSO EXTEND INTO
MIAMI-DADE. FOR THE WEST COAST THERE IS ONLY A SMALL CHANCE OF
THUNDERSTORMS, SINCE MOST OF THE SURFACE TROUGH IS ALIGNED FROM
NORTHEAST TO SOUTHWEST OVER THE ATLANTIC WATERS.
AS MENTIONED IN THE PREVIOUS DISCUSSION THE UPPER LEVEL
TEMPERATURES ARE FORECAST TO COOL ON SUNDAY ALLOWING FOR A GREATER
CHANCE OF THUNDERSTORMS THAN TODAY.
FOR TODAY THE HIGHEST POPS ARE STILL INCLUDED FOR PALM BEACH AND
BROWARD.
PREV DISCUSSION... /ISSUED 725 AM EDT SAT APR 20 2013/
AVIATION...
MOSTLY VFR CONDITIONS WILL OCCUR EARLY IN THE FORECAST ALTHOUGH
THERE COULD BE A BRIEF MVFR CIG AS A FEW SHOWERS MOVE ACROSS SOUTH
FLORIDA. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP BY THIS AFTERNOON AHEAD OF A WEAKENING COLD
FRONT THAT WILL SAG ACROSS THE REGION. THE HRRR INDICATES
CONVECTION TO BEGIN DEVELOPING IN EARNEST BETWEEN 18-20Z WITH THE
STEERING FLOW TAKING THE STORMS TO THE EAST COAST. THEREFORE, HAVE
LEFT TEMPO 18-22Z FOR ALL EAST TERMINALS WITH SOME OF THE ACTIVITY
POSSIBLY PERSISTING BEYOND THIS TIME FRAME. SURFACE WINDS ARE
QUESTIONABLE WITH A SLOW MOVING FRONTAL BOUNDARY BUT GENERALLY
SSW-SSE AHEAD OF THE FRONT AND NE BEHIND THE FRONT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 73 84 70 83 / 40 60 40 60
FORT LAUDERDALE 74 85 72 84 / 30 60 40 60
MIAMI 75 86 73 85 / 30 50 40 60
NAPLES 69 86 70 84 / 20 40 40 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS MIAMI FL
1009 AM EDT FRI APR 19 2013
.UPDATE...
A FEW LIGHT SHOWERS CONTINUE TO PUSH ONSHORE THE ATLANTIC COAST
UNDER SOUTHEAST FLOW. THESE SHOWERS ARE VERY LIGHT AND WILL
CONTINUE TO PUSH NORTHWEST ACROSS BROWARD AND MIAMI-DADE COUNTIES
THROUGH THE MORNING. LATEST HRRR INITIALIZED WELL AND KEEPS THESE
SHOWERS AND POSSIBLY A FEW THUNDERSTORMS ACROSS NORTHERN INTERIOR
AREAS THROUGH THE AFTERNOON. INCREASED POPS SLIGHTLY ACROSS THE
EAST COAST AND ADJUSTED TEMPERATURES TO ACCOUNT FOR CURRENT
TRENDS...OTHERWISE CURRENT FORECAST IS ON TRACK. UPDATE SENT.
&&
.PREV DISCUSSION... /ISSUED 808 AM EDT FRI APR 19 2013/
AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGH THE NEXT 24 HOURS OUTSIDE ANY
BRIEF PERIODS OF SHOWERS AND/OR A STORMS IN THE VICINITY OF THE
SITES ALTHOUGH THOSE CHANCES ARE SMALL AT THE PRESENT TIME. SE
WINDS OF 10-15 KNOTS AND GUSTY ALONG SE COAST TODAY BECOMING
5-10KT OVERNIGHT. AT KAPF SSE WIND OF 10 TO 15 KNOTS AND GUSTY
BECOMING SSW LATE THIS AFTERNOON FOR A COUPLE OF HOURS AND SE
5-10KT OVERNIGHT.
PREV DISCUSSION... /ISSUED 341 AM EDT FRI APR 19 2013/
DISCUSSION...
THE GUIDANCE HAS BEEN VERY CONSISTENT INDICATING THAT A COLD FRONT
WILL ENTER THE FLORIDA PANHANDLE LATER TODAY THEN CONTINUE TO MOVE
SOUTHEAST INTO NORTH CENTRAL FLORIDA ON SATURDAY AND THEN STALL
WHILE BECOMING SOMEWHAT DIFFUSE LATE SATURDAY THROUGH SUNDAY. AT
THE MID TO UPPER LEVELS...A WEAK RIDGE TODAY WILL ERODE BY THE
WEEKEND WITH A MID TO UPPER LEVEL TROUGH DIGGING INTO THE EASTERN
AND CENTRAL GULF WITH THE FLORIDA PENINSULA TO THE EAST OF THE
TROUGH AXIS.
FOR TODAY...A MODERATE SOUTHEASTERLY FLOW WILL PREVAIL ACROSS THE
REGION WITH INCREASING MOISTURE AS THE DAY PROGRESSES WITH
REGIONAL PWATS REACHING ABOUT 1.5 INCHES LATER TODAY. GIVEN THE
INCREASING MOISTURE AND ELEVATED DEW POINTS ACROSS THE
REGION...FOR THIS AFTERNOON ISOLATED THUNDERSTORMS WILL BE
POSSIBLE BUT MAINLY EXPECTED IN THE INTERIOR REGIONS AND WEST. IF
THE WEST COAST SEA BREEZE DEVELOPS LATER THIS AFTERNOON SCATTERED
SHOWER AND THUNDERSTORM ACTIVITY IS POSSIBLE IN THE WESTERN
INTERIOR AND IS INDICATED IN THE FORECAST.
FOR THE WEEKEND...THE GUIDANCE HAS BEEN CONSISTENTLY INDICATING
THAT DEEPER LAYERED MOISTURE IS EXPECTED TO ENTER THE REGION AND
A MID TO UPPER LEVEL TROUGH DEVELOPING WEST OF THE FLORIDA PENINSULA.
IN ADDITION SYNOPTIC SCALE LIFT IS FORECAST FOR THE MID TO UPPER
LEVELS. ALL THESE ELEMENTS WILL RESULT IN THE POTENTIAL FOR
CONVECTION ACROSS THE REGION SATURDAY AND SUNDAY. FORECAST
SOUNDINGS INDICATE THAT PWATS COULD REACH NEAR 1.8 INCHES LATER
ON SATURDAY BUT THE SOUNDINGS SO FAR DO NOT INDICATE A WIND
PROFILE OR THERMODYNAMIC PROFILE THAT MAY SUPPORT SEVERE
THUNDERSTORMS OR WEATHER. FOR SATURDAY...MAINLY AFTERNOON AND EARLY
EVENING SCATTERED SHOWERS AND THUNDERSTORMS ARE FORECAST WITH THE
COVERAGE POSSIBLY GREATER ALONG THE EASTERN THIRD OF THE PENINSULA
AND THE ADJACENT GULF WATERS. VERY SIMILAR CONDITIONS ARE EXPECTED
ON SUNDAY AFTERNOON ALTHOUGH THE FORECAST SOUNDINGS INDICATE THAT
THE MID LEVELS WILL COOL AND THE MID TO UPPER LEVEL TROUGH MAY BE
IN A MORE FAVORABLE POSITION TO SUPPORT MORE ORGANIZED CONVECTION.
FOR NOW...ON SUNDAY MAINLY SCATTERED SHOWERS AND THUNDERSTORMS ARE
FORECAST BUT WOULD NOT BE SURPRISED IF THE FUTURE GUIDANCE
INDICATES MORE WIDESPREAD COVERAGE.
FOR THE EXTENDED PERIODS...GUIDANCE INDICATES THAT LINGERING
MOISTURE ACROSS THE REGION ON MONDAY AND FAVORABLE MID TO UPPER
LEVELS MAY ALLOW FOR A CHANCE OF SHOWERS AND THUNDERSTORMS. AFTER
MONDAY NORMAL DIURNALLY DRIVEN SHOWERS AND ISOLATED THUNDERSTORMS
MAY BE POSSIBLE FOR THE REMAINDER OF THE WEEK.
MARINE...
WINDS AND SEAS MAINLY EXPECTED TO BE BELOW ADVISORY LEVELS THROUGH
THE FORECAST PERIOD BUT OVER THE WEEKEND THUNDERSTORMS ARE
FORECAST AND WINDS AND SEAS COULD BE LOCALLY HIGHER IN OR NEAR
THUNDERSTORMS.
FIRE WEATHER...
NO FIRE WEATHER CONCERNS BUT OVER THE WEEKEND THUNDERSTORMS ARE
FORECAST WITH A SLIGHT CHANCE OF SEVERE WEATHER.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 85 74 84 70 / 20 30 50 40
FORT LAUDERDALE 85 76 84 72 / 20 30 50 40
MIAMI 86 75 84 72 / 20 20 50 40
NAPLES 89 72 84 68 / 30 20 40 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...13/SI
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
738 PM EDT SAT APR 20 2013
.SYNOPSIS...
A STATIONARY FRONT WILL LINGER OFF THE SOUTHEAST COAST INTO EARLY
NEXT WEEK...AS HIGH PRESSURE BUILDS FROM THE NORTH. A COLD FRONT
WILL MOVE ACROSS THE AREA WEDNESDAY OR THURSDAY...FOLLOWED BY HIGH
PRESSURE LATE IN THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
EARLY SATURDAY EVENING...BACK EDGE OF MID/HIGH LEVEL CLOUD SHIELD
CONTINUED TO STREAM OVER COASTAL COUNTIES BUT WAS POISED TO
ADVANCE OFFSHORE...LEAVING MAINLY CLEAR SKIES ONLY PUNCTUATED BY
ADDITIONAL CIRRUS PUSHING INTO THE REGION FROM THE WEST OVERNIGHT.
ONGOING FORECASTS REMAINED IN DECENT SHAPE AND REQUIRED ONLY
MINOR ADJUSTMENTS TO HOUR;LY PARAMETERS THIS EVENING.
LARGE HIGH PRES WL MOVE INTO THE OHIO VALLEY TNGT WHILE XTNDG
WELL TO THE S. RAP FCST SOUNDINGS SUGGEST THE BNDRY LYR WL GRADUALLY
DECOUPLE THIS EVNG EVENTUALLY YIELDING A LIGHT/CALM WND REGIME.
THIS COUPLED WITH CLR SKIES AND LOW DEWPTS WL SUPPORT A DECENT
RADIATIONAL SETUP WITH LOWS DROPPING INTO THE LWR 40S INLAND TO
THE LWR-MID 50S AT THE BEACHES WHERE WNDS WL LIKELY STAY UP A BIT.
IT IS NOT OUT OF THE REALM OF POSSIBILITY THAT A FEW UPR 30S COULD
OCCUR IN SOME OF THE NORMALLY COLDER LOCATIONS SUCH AS ALLENDALE
AND JAMESTOWN. 20/12Z GFS-COOP GUIDANCE IS FCSTG UPR 30S IN
SEVERAL OF THE FAR INLAND STATIONS. FROST IS NOT A CONCERN EVEN IF
UPR 30S WHERE TO OCCUR.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
SUNDAY...A COLD FRONT WILL STALL WELL OFF THE SOUTHEAST COAST SUNDAY
WHILE LARGE SFC HIGH PRESSURE BECOMES CENTERED OVER THE NORTHEASTERN
UNITED STATES. THIS WILL RESULT IN UNSEASONABLY COOL CONDITIONS OVER
THE SOUTHEASTERN UNITED STATES AS BRISK NORTHEAST WINDS DEVELOP IN
RESPONSE TO A TIGHT PRESSURE GRADIENT BETWEEN THE STALLED BOUNDARY
AND HIGH PRESSURE TO THE NORTH. WE COULD SEE A PERIOD OF GUSTY WINDS
BETWEEN 25-30 MPH SUNDAY AFTERNOON AS TEMPS APPROACH THE UPPER 60S
TO AROUND 70...BUT CONDITIONS SHOULD FALL SHORT OF WIND ADVISORY
CRITERIA. CHANCES OF RAIN/SHOWERS WILL THEN INCREASE ALONG COASTAL
COUNTIES THROUGH SUNDAY EVENING AS ISENTROPIC ASCENT AND LOW LVL
MOISTURE INCREASE OVER THE AREA IN RESPONSE TO LOW PRESSURE
DEVELOPING ALONG THE STALLED BOUNDARY OFFSHORE. HAVE MAINTAINED THE
CURRENT PRECIP FORECAST WITH A SLIGHT CHANCE OF SHOWERS INLAND AND
CHANCE OF SHOWERS ALONG COASTAL COUNTIES.
MONDAY AND TUESDAY...CLOUDY AND COOL CONDITIONS WILL LIKELY PERSIST
INTO EARLY NEXT WEEK AS MOISTURE LINGERS ALONG THE WESTERN EDGE OF
LOW PRESSURE DEEPENING ALONG THE SOUTHEAST COAST AND HIGH PRESSURE
WEDGING OVER LAND. A SLIGHT CHANCE OF RAIN/SHOWERS AND GUSTY WINDS
WILL BE POSSIBLE ON MONDAY...MAINLY ALONG COASTAL COUNTIES WHERE
MOISTURE IS GREATEST AND THE PRESSURE GRADIENT REMAINS PINCHED
BETWEEN THE DEPARTING LOW TO THE NORTHEAST AND HIGH PRESSURE OVER
LAND. BY TUESDAY...CONDITIONS WILL GRADUALLY WARM AND DRY UNDER
ZONAL FLOW WHILE SFC HIGH PRESSURE SLIDES TO THE COAST AND THE OFFSHORE
LOW SHIFTS FURTHER NORTH AND EAST AWAY FROM THE REGION. OVERALL HIGH
TEMPS SHOULD REACH THE UPPER 60S TO AROUND 70 ON MONDAY...BEFORE
WARMING INTO THE LOW 70S ON TUESDAY.
LAKE WINDS...STRONG NORTHEAST WINDS ARE EXPECTED SUNDAY AFTERNOON
AND SUNDAY NIGHT AS HIGH PRESSURE BUILDS FROM THE NORTH AND
TEMPERATURES PROFILES BECOME FAVORABLE FOR MIXING OF STRONG
LOW-LEVEL WINDS DOWN OVER THE RELATIVELY WARMER LAKE WATERS.
THUS...A LAKE WIND ADVISORY MAY BE NEEDED DURING THIS TIME.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HIGH PRESSURE WILL BE SLIPPING OFFSHORE TUESDAY NIGHT INTO WEDNESDAY
AS A COLD FRONT APPROACHES FROM THE WEST. THERE IS STILL SOME
UNCERTAINTY REGARDING THE TIMING OF THE COLD FRONTAL PASSAGE
WEDNESDAY OR THURSDAY...AND IT COULD EVEN STALL OUT OVER OR NEAR THE
AREA. FOR NOW WE HAVE KEPT RAIN CHANCES LOW AND MAINLY THROUGH
THURSDAY WITH DRIER CONDITIONS FRIDAY. RAIN CHANCES COULD INCREASE
AGAIN LATER SATURDAY AS ANOTHER COLD FRONT BEGINS TO APPROACH FROM
THE WEST. TEMPERATURES ARE TRICKY AS MUCH DEPENDS ON THE TIMING OF
THE FRONTAL PASSAGE BUT FOR NOW HAVE KEPT THEM NEAR TO BELOW NORMAL.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
NE WINDS WILL STRENGTHEN SUNDAY MORNING AND WILL VEER TOWARD THE E
SUNDAY AFTERNOON...WITH GUSTS AROUND 30 KT POSSIBLE AFTER 18Z.
ALSO...LIGHT RAIN COULD SPREAD INTO TERMINALS ESPECIALLY KSAV
SUNDAY AFTERNOON...BUT POPS REMAIN TOO LOW TO JUSTIFY ANY MENTION
WITHIN 00Z TAFS. OTHERWISE...VFR THROUGH SUNDAY...WITH AN
INCREASING PROBABILITY FOR MVFR CEILINGS LATE IN THE 00Z TAF
PERIOD.
EXTENDED AVIATION OUTLOOK....MVFR CIGS EXPECTED SUNDAY EVENING...
POSSIBLY INTO EARLY TUESDAY. BREEZY/GUSTY CONDITIONS EXPECTED
MONDAY.
&&
.MARINE...
TONIGHT...N WNDS WL GRADLY VEER TO THE NE AS HIGH PRES BUILDS IN
FROM THE S. SPEEDS WL BEGIN TO STEADILY INCR AFT MIDNGT AS THE
PRES GRADIENT BETWEEN HIGH PRES TO THE N AND THE REMNANT CDFNT
DEGENERATES INTO A SHARPENING COASTAL TROUGH. XPCT NE WINDS OF
15-20 KT TO DOMINATE NEARSHORE WTRS AND 20-25 KT OFFSHORE WTRS
BY SUNRISE SUN. SEAS WL BUILD IN RESPONSE TO THE STRENGTHENING
WINDS...BUILDING TO 3-5 FT NEARSHORE WATERS EDISTO BEACH S...4-6
FT FOR THE CHARLESTON COUNTY COASTAL WATERS AND 5-7 FT OFFSHORE
WATERS. WL HOIST A SMALL CRAFT ADVISORY FOR THE GEORGIA OFFSHORE LEG
BEGINNING AND MIDNIGHT AND THE CHARLESTON COUNTY WATERS BEGINNING
A 5 AM SUNDAY.
SUNDAY THROUGH THURSDAY...MARINE CONDITIONS WILL DETERIORATE DURING
THE BEGINNING OF THE WEEK AS AN ENHANCED PRESSURE GRADIENT DEVELOPS
BETWEEN A STALLING COLD FRONT OFFSHORE AND STRONG HIGH PRESSURE
BUILDING OVER LAND. STRONG COLD AIR ADVECTION FROM THE
NORTH/NORTHWEST ALONG WITH 40-45 KT 1000 MB GEOSTROPHIC WINDS
SUGGEST GALE FORCE WIND GUSTS BETWEEN 35-40 KT OVER ALL WATERS
SUNDAY AFTERNOON INTO EARLY MONDAY. THE BEST CHANCE OF GALE FORCE
WINDS WILL REMAIN OVER WARMER WATER TEMPS IN NORTHERN SC WATERS AND
OUTER GEORGIA WATERS. SEAS MAY ALSO APPROACH 10-12 FT BEYOND 10 NM
FROM THE COAST SUNDAY NIGHT INTO EARLY MONDAY. CONDITIONS SHOULD
DROP BELOW ADVISORY LEVELS FOR MUCH OF THE NEARSHORE WATERS MONDAY
NIGHT AND ACROSS THE OUTER WATERS TUESDAY. A COLD FRONT WILL LIKELY
PUSH THROUGH THE WATERS WEDNESDAY OR THURSDAY BUT CONDITIONS LOOK TO
REMAIN BELOW ADVISORY LEVELS.
RIP CURRENTS...THE COMBINATION OF INCREASING WINDS ALONG THE
BEACHES AND BUILDING SURF WILL SUPPORT A MODERATE RISK FOR RIP
CURRENTS ALONG THE SOUTH CAROLINA BEACHES AND A HIGH RISK FOR THE
GEORGIA BEACHES ON SUNDAY. THERE ARE SOME INDICATIONS IN THE
LATEST WW4 OUTPUT THAT THE UNDERLYING SWELL PERIOD COULD REACH AS
HIGH AS 10 SECONDS. SHOULD THIS VERIFY...THEN THE RISK WOULD TIP
INTO THE HIGH CATEGORY FOR THE SOUTH CAROLINA BEACHES AS WELL. AN
ENHANCED RISK FOR RIP CURRENTS WILL PERSIST FOR THE NEXT SEVERAL
DAYS.
&&
.TIDES/COASTAL FLOODING...
STRONG NORTHEAST WINDS SUNDAY AND SUNDAY NIGHT WILL LEAD TO
BUILDING SEAS...ROUGH SURF...BEACH EROSION AND SHALLOW COASTAL
FLOODING. A COASTAL FLOOD ADVISORY AND HIGH SURF ADVISORY MAY
EVENTUALLY BE NEEDED.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...HIGH RISK FOR RIP CURRENTS FROM SUNDAY MORNING THROUGH SUNDAY
EVENING FOR GAZ117-119-139-141.
SC...NONE.
MARINE...GALE WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING FOR
AMZ330-352-354.
GALE WATCH FROM SUNDAY MORNING THROUGH MONDAY AFTERNOON FOR
AMZ350-374.
SMALL CRAFT ADVISORY FROM 5 AM TO 11 AM EDT SUNDAY FOR AMZ350.
SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM EDT SUNDAY
FOR AMZ374.
&&
$$
SYNOPSIS...
NEAR TERM...SPR/ST
SHORT TERM...DPB
LONG TERM...RJB
AVIATION...SPR
MARINE...SPR/DPB/ST
TIDES/COASTAL FLOODING...
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1054 PM MDT THU APR 18 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 218 PM MDT THU APR 18 2013
EARLY AFTERNOON WV IMAGERY AND RUC H5 ANALYSIS SHOWS POSITIVELY
TILTED TROUGH EXTENDING FROM THE NORTHERN PLAINS ALONG KS/CO BORDER.
AT THE SURFACE HIGH PRESSURE IS IN PLACE OVER EASTERN
COLORADO...WITH A 996MB SURFACE LOW CENTERED OVER THE NORTHERN
MISSISSIPPI VALLEY. NORTHWEST GRADIENT IS IN PLACE AT THE SURFACE
ACROSS OUR CWA...WITH WINDS GUSTING TO 40 MPH.
SEVERAL LOCATIONS INCLUDING KGLD AND KITR HAVE REPORTED SUSTAINED
WINDS WITHIN ADVISORY CRITERIA THIS AFTERNOON. THESE WINDS HAVE BEEN
SHORT LIVED AT THESE LOCATIONS WITH THE OVERALL TREND ACROSS THE
AREA TO REMAIN BELOW ADVISORY CRITERIA...SO NO HIGHLIGHT PLANNED AT
THIS POINT. THERE WAS SOME CONCERN THAT THERE WOULD BE PATCHY
BLOWING SNOW WITH THESE WINDS...AND TO THIS POINT NO REPORTS OF
REDUCED VISIBILITIES HAVE BEEN REPORTED SO FAR THIS AFTERNOON. WITH
FRESHLY FALLEN SNOW AND GUSTS TO 40 MPH I STILL COULDNT RULE THIS
OUT THIS AFTERNOON ESPECIALLY ACROSS OPEN AREAS IN THE COUNTRY SO I
PLAN ON LEAVING PATCHY BLOWING SNOW MENTION IN PLACE THROUGH THE
AFTERNOON HOURS.
OTHER IMMEDIATE FORECAST CONCERN THIS AFTERNOON IS POTENTIAL FOR
FLURRIES (OR SPRINKLES WHERE SURFACE TEMPS ARE ABOVE FREEZING).
RADAR CONTINUES TO SHOW LIGHT RETURNS ACROSS OUR FORECAST
AREA...ASSOCIATED WITH BANDS OF STRATOCUMULUS THAT HAS DEVELOPED
WITH COLD POOL ON BACK SIDE OF UPPER LOW. THERE HAVE BEEN NO RECENT
REPORTS OF PRECIP...HOWEVER I COULDNT RULE OUT NON MEASURABLE
BEFORE SUNSET.
TONIGHT-FRIDAY...WINDS SHOULD DIMINISH AFTER SUNSET AND WITH
UNSEASONABLY COOL AIR MASS IN PLACE AND CLEARING SKIES WE COULD END
UP WITH NEAR RECORD LOW TEMPS AT A FEW LOCATIONS (ESPECIALLY IF
WINDS GO CALM). WINDS SHOULD STILL BE IN THE 10-15 MPH RANGE WHICH
SHOULD LIMIT COOLING. I KEPT FORECAST IN THE UPPER TEENS-LOW 20S FOR
MOST OF THE AREA...WHICH IS ABOVE PREVIOUS DAILY RECORDS. DRY
CONDITIONS AND MILD TEMPS ARE EXPECTED THROUGH THE DAY THU WITH W/NW
FLOW ALOFT AND LEE TROUGH REBUILDING. MODEL SOUNDINGS ARE DRY
ADIABATIC TO ABOUT 700MB AND IF IT WASNT FOR RECENT SNOWFALL I MIGHT
BE CONCERNED WITH POTENTIAL RFW CONDITIONS FRI AFTERNOON.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 218 PM MDT THU APR 18 2013
FORECAST PROBLEMS WILL BE HOW MUCH IT WARMS UP THROUGH THE WEEKEND
BEFORE THE NEXT COLD FRONT MOVES THROUGH AND THE PRECIPITATION
CHANCES THIS WEEKEND AND CONTINUING INTO THE BEGINNING OF NEXT WEEK.
SATELLITE SHOWING THE LARGE SCALE FLOW PATTERN BEING AMPLIFIED AND
BLOCKY FROM THE PACIFIC INTO THE EASTERN NORTH AMERICA. SYSTEM THAT
HAS BROUGHT 2 TO 5 INCHES OF SNOW AND A LOT OF WIND TO THE AREA IS
CONTINUING TO MOVE TOWARD THE EAST. COLD AIR MASS HAS SETTLED OVER
THE REGION.
MODELS APPEAR TO START OUT FINE ON THE UPPER JET. WITH OUR EXITING
SYSTEM AND OVERALL MID LEVELS...THE UKMET WAS DOING A LITTLE BETTER
THAN THE ECMWF AND THE CANADIAN. NAM/ECMWF WERE DOING THE BEST ON
THE SURFACE PRESSURE/WIND FIELD. THE NAM WAS DOING SLIGHTLY BETTER
THAN THE GFS AND SREF ON THE LOW LEVEL THERMAL FIELD.
FRIDAY NIGHT...LEFT FRONT QUADRANT OF THE JET IS NOW MUCH FURTHER
SOUTHWEST OF THE AREA THAT WHAT THE MODELS WERE SHOWING 24 HOURS
AGO. ALSO MID LEVEL LIFT IS BETTER ON EITHER SIDE...ESPECIALLY TO
THE SOUTH. SO WILL KEEP THIS PERIOD DRY. WINDS WILL BECOME LIGHT AND
VARIABLE. AT THE SAME TIME...MID AND HIGH LEVEL CLOUD COVER BECOME
RATHER THICK. SO EXPECT THE CLOUD COVER TO KEEP THE TEMPERATURES FROM
DROPPING TOO MUCH.
SATURDAY/SATURDAY NIGHT...MAIN JET IS STILL FAR TO THE SOUTHWEST OF
THE AREA. MIXED SIGNALS ON CHANCE OF PRECIPITATION. MOISTURE REMAINS
ABOVE 700 MB WITH ONLY WEAK MID LEVEL LIFT IN PLACE. THETA-E LAPSE
RATES ARE GOOD WITH LITTLE TO NO SURFACE/ELEVATED CAPE IN PLACE.
MODELS HAVE LIGHT QPF SCATTERED ALL OVER THE PLACE. FEELING IS THAT
NOT MUCH IS GOING TO REACH THE GROUND. SO REMOVED POPS AND REPLACED
THE AFTERNOON/EVENING WEATHER GRIDS WITH SPRINKLES.
SNOW IS EXPECTED TO MELT PRETTY QUICK SO DO NOT THINK THERE WILL BE
MUCH IF ANY AFFECT ON THE TEMPERATURES. MODELS ARE ALL OVER THE PLACE
WITH THE WIND FIELD. CONSIDERING THE NUMEROUS SHORTWAVE TROUGHS
EMBEDDED WITHIN THE FAST WESTERLY FLOW ALOFT...CAN UNDERSTAND THE
MODEL DIFFICULTIES. OVERALL CONSENSUS WITH THE LIGHT FIELD IS TO HAVE
WINDS FROM AN UPSLOPE DIRECTION. SO THE WINDS WILL NOT HELP WITH THE
WARMUP. AND CONSIDERING THE RATHER THICK CLOUD COVER...AM NOT SOLD ON
A BIG WARM UP. HOWEVER...MODELS HAVE BEEN UNDERDOING WARMUPS RECENTLY
AND CONSIDERING POSSIBLE SNOW FIELD CONTAMINATION...THAT COULD BE THE
CASE HERE. RIGHT NOW WILL GO NEAR THE WARMEST GUIDANCE.
SAME THING WITH THE WIND FIELD FOR THE NIGHT PERIOD WITH WINDS
RATHER LIGHT AND VARIABLE. WILL HAVE DECENT MID/UPPER LEVEL CLOUD
COVER UNTIL LATE IN THE NIGHT. IT LOOKS LIKE THE MINS WILL BE
WARMER DUE TO THE CLOUDS BUT CAN SEE WHERE MINS COULD REALLY DROP
OFF.
SUNDAY...WITH THE EXCEPTION OF THE NAM...MODELS ARE IN AGREEMENT IN
HAVING THE LEFT FRONT QUADRANT OF A STRONG UPPER JET AFFECTING THE
WEST/SOUTHWEST PORTION OF THE AREA IN THE AFTERNOON. THE MODELS HAVE
LESS MOISTURE AROUND THAN THE PREVIOUS DAY. BUT CANNOT IGNORE THIS
INCOMING JET. SOME OF THE MODEL OUTPUT IS PRODUCING LIGHT QPF. SO
AT THIS TIME HAVE PUT IN A SLIGHT CHANCE IN THE AFTERNOON. THIS
TRANSITIONS WELL INTO WHAT THE INIT HAS GIVEN ME FOR SUNDAY NIGHT.
MODEL WIND FIELDS CONTINUE TO BE IN CHAOS AND DISAGREEMENT...WHICH
PROBABLY MEANS LIGHT AND VARIABLE. THIS WIND DISAGREEMENT TRANSLATES
INTO LOW LEVEL THERMAL DISAGREEMENT. THERE LOOKS LIKE THERE WILL BE
MORE SUN THAN THE PREVIOUS FEW DAYS PLUS WINDS MAY END UP DOWNSLOPE.
SO RAISED MAXES SOME.
SUNDAY NIGHT THROUGH THURSDAY...LEFT FRONT QUADRANT/JET AXIS OF THE
ABOVE MENTIONED JET CONTINUES TO STRONGLY AFFECT THE AREA FROM
SUNDAY NIGHT THROUGH MONDAY NIGHT INTO EARLY TUESDAY MORNING. MODELS
ARE IN A LITTLE CLOSER AGREEMENT THAN YESTERDAY. THE ECMWF WHICH
HAS BEEN THE MOST CONSISTENT...HAS SLOWED DOWN/IS FURTHER NORTH WITH
INCOMING UPPER TROUGH. THE ECMWF IS ALSO SLOWER THAN THE REMAINING
MODEL OUTPUT.
SO LIKED AND ACCEPTED WHAT THE CRH INIT GAVE ME FOR POPS THROUGH
TUESDAY WHICH WAS NOT TOO DIFFERENT THAN WHAT THE INIT HAS BEEN
PRODUCING THE LAST COUPLE OF DAYS. SO THAT MEANS A CONTINUED GOOD
CHANCE OF PRECIPITATION FROM SUNDAY NIGHT AND ESPECIALLY MONDAY INTO
MONDAY NIGHT. PRECIPITATION ENDS TUESDAY WITH A DRY FORECAST FOR
TUESDAY NIGHT INTO WEDNESDAY. FOR THURSDAY MODELS AGREE WITH HAVING
NORTHWEST FLOW ALOFT OVER THE AREA WITH EMBEDDED SHORTWAVE TROUGH(S)
IN THIS FLOW...ALWAYS A DANGEROUS SCENARIO AND NEVER CAN RULE OUT ANY
PRECIPITATION. SO THE SLIGHT CHANCE THE INIT GAVE ME LOOKS
REASONABLE.
THANKS TO ALL FOR THE COLLABORATION WHO CHOSE TO COLLABORATE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1053 PM MDT THU APR 18 2013
A CLEAR SKY WILL PREVAIL AT KGLD AND KMCK OVERNIGHT AND FRIDAY
MORNING AS HIGH PRESSURE AND SUBSIDENCE MOVE INTO THE REGION. SOME
SCATTERED CLOUDS WILL DEVELOP FRIDAY AROUND MIDDAY WITH WIND
BECOMING BREEEZY. WIND WILL BECOME LIGHT AS THE ATMOSPHERE DECOUPLES
FRIDAY EVENING. MID LEVEL CLOUDS WILL INCREASE FRIDAY EVENING BUT
CONDITIONS WILL REMAIN VFR WITH NO PRECIPITATION EXPECTED.
&&
.CLIMATE...
ISSUED AT 315 AM MDT THU APR 18 2013
RECORD LOW TEMPERATURES FRIDAY MORNING:
GOODLAND.....18 DEGREES (1953)
HILL CITY....23 DEGREES (1953)
MCCOOK.......22 DEGREES (1953)
BURLINGTON...17 DEGREES (1966)
COLBY........19 DEGREES
TRIBUNE......19 DEGREES
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...FS
CLIMATE...DDT
AREA FORECAST DISCUSSION
NWS JACKSON KY
136 AM EDT FRI APR 19 2013
.UPDATE...
ISSUED AT 1105 PM EDT THU APR 18 2013
HOURLY TEMPS...SKY...POPS AND DEWPOINTS WERE FRESHENED UP BASED ON
RECENT OBS AND MODEL TRENDS. PURE EXTRAPOLATION OF SHRA AND SOME TSRA
NOW OVER WESTERN KY AND WESTERN TN WOULD BRING IT INTO OUR AREA
A LITTLE SLOWER THAN OUR CURRENT FORECAST. WE CURRENTLY WENT WITH A
BLEND OF 18Z GFS AND 18Z AND 21Z SREF AS WELL AS THE 21Z HRRR.
OVERALL...WE EXPECT THE BAND OF PRECIP TO SPEED UP AS A SHORTWAVE
ROTATES INTO THE SOUTHEASTERN STATES. THE 23Z HRRR AND 0Z NAM ARE
ABOUT AN HOUR SLOWER...BUT THE BOTTOM LINE IS THAT IN MOST LOCATIONS
IT WILL BE RAINING DURING THE MORNING COMMUTE. NEAR THE ONSET OF THE
PRECIPITATION IS THE PERIOD WHEN LAKE WIND ADVISORY CRITERIA WINDS
ARE MOST LIKELY. OPEN TERRAIN AREAS AS WELL AS THE HIGH TERRAIN WILL
BE GUSTY ALL NIGHT. INSTABILITY IS PROGGED TO BE LIMITED AND GIVEN
EXTREMELY LIMITED LIGHTNING OPTED TO DECREASE COVERAGE OF THUNDER TO
MORE ISOLATED TO SCATTERED.
UPDATE ISSUED AT 815 PM EDT THU APR 18 2013
HOURLY TEMP...DEWPOINT AND WINDS WERE FRESHENED UP BASED ON RECENT
OBSERVED TRENDS. IT STILL APPEARS THAT OTHER THAN A POSSIBLE STRAY
SHOWER...CONVECTION WILL BE CONFINED TO RIGHT ALONG AND JUST BEHIND
THE COLD FRONT OVERNIGHT TONIGHT...AND AFTER MIDNIGHT ACROSS THE
ENTIRE REGION. ANY THUNDERSTORM OR STRONGER SHOWER WOULD BE ABLE TO
TRANSFER SOME OF THE MOMENTUM FROM STRONGER WINDS ALOFT. A STRAY GUST
EXCEEDING 40 MPH IS NOT OUT OF THE QUESTION. THE CHANCES FOR THIS ARE
PROBABLY GREATEST ALONG AND WEST OF I 75 AND ACROSS THE EASTERN
BLUEGRASS COUNTIES. LOWER DEWPOINTS AND LIMITED INSTABILITY CURRENTLY
OVER CENTRAL AND EASTERN KY AND EXPECTED TO REMAIN WILL BE A LIMITING
FACTOR TO CONVECTION AS IT MOVES EAST...BUT DRIER AIR NEAR THE SFC
COULD CONTRIBUTE TO SOME GUSTINESSS AS WELL. EVEN STILL DYNAMICS OF
THE ASSOCIATED TROUGH AND CONVERGENCE ALONG THE FRONT SHOULD LEAD TO
WIDESPREAD COVERAGE OF CONVECTION JUST AHEAD AND A FEW HOURS BEHIND
THE FRONT.
ALTHOUGH VALLEY LOCATIONS...AND PERHAPS OTHER LOCATIONS AS WELL MAY
EXPERIENCE A LULL IN THE WIND GUSTS OVER THE NEXT FEW HOURS...AS THE
FRONT APPROACHES AND AS THE PRECIP ARRIVES WINDS WILL AGAIN GUST TO
LAKE WIND ADVISORY CRITERIA...OR 35 TO 40 MPH ON AVERAGE. A FEW GUSTS
OVER 40 MPH WILL BE POSSIBLE IN ANY OF THE STRONGER CONVECTION.
OTHERWISE...HOURLY TEMP CURVES WILL BE A BIT TRICKY OVERNIGHT...ESPECIALLY
EASTERN VALLEYS THAT MAY DECOUPLE TO SOME DEGREE OVER THE NEXT 6
HOURS AND THEN AS CLOUDS AND GRADIENT INCREASE AND PRECIP ARRIVES
JUMP UP SEVERAL DEGREES BEFORE FALLING BEHIND THE FRONT.
THE POST FRONTAL AIRMASS WILL BE COLD...BUT RATHER SHALLOW. THE NAM
AND ITS HIGHER RESOLUTION AND MORE MODEL LEVELS STILL APPEARS TO HAVE
THE BEST HANDLE FOR HOURLY TEMPS LATE TONIGHT AND INTO FRI COMPARED
TO MOS OR OTHER GUIDANCE. WETBULBING SHOULD LEAD TO AN INITIAL DROP
IN TEMPS AS PRECIP ARRIVES LATE TONIGHT AND INTO FRI MORNING...AND
COLD AIR ADVECTION AND CLOUDS SHOULD LEAD TO A RATHER LIMITED TEMP
RISE ON FRI AFTERNOON.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 330 PM EDT THU APR 18 2013
18Z SFC ANALYSIS SHOWS A DEEP AREA OF LOW PRESSURE LIFTING NORTHEAST
INTO THE UPPER MIDWEST. FROM THIS...A POWERFUL COLD FRONT IS
APPROACHING THE MISSISSIPPI RIVER...KICKING OFF A LARGE LINE OF
STRONG TO SEVERE STORMS. EAST KENTUCKY IS ENJOYING A WARM AND PARTLY
SUNNY DAY OUT AHEAD OF THE FRONT...THOUGH IT IS QUITE BREEZY WITH
GUSTS PUSHING 30 MPH...AND 35 MPH WEST OF INTERSTATE 75. THIS IS
STRONG ENOUGH FOR A LAKE WIND ADVISORY AND ONE REMAINS IN EFFECT FOR
THE ENTIRE AREA...THOUGH WINDS WILL BE A NOTCH LIGHTER OVER OUR
NORTHEAST COUNTIES. THE SOUTH WINDS AND TIMES OF SUNSHINE HAVE PUSHED
READINGS INTO THE UPPER 70S AND LOW 80S THROUGH THE CWA THIS
AFTERNOON WITH ANOTHER COUPLE OF DEGREES POSSIBLE IN MOST PLACES. AT
THE SAME TIME...DEWPOINTS ARE GENERALLY IN THE MID 50S.
THE MODELS ARE IN GOOD AGREEMENT ALOFT AS THEY ALL DEPICT OUR CURRENT
OVERHEAD RIDGING YIELDING TO A DEEP TROUGH CARVING ITS WAY THROUGH
THE UPPER MIDWEST BEFORE LIFTING INTO THE WESTERN GREAT LAKES ON
FRIDAY. A LARGE ENERGY TAIL WILL SWEEP THROUGH THE OHIO VALLEY DURING
THE DAY WITH THIS TRANSITION. THIS WILL BE FOLLOWED BY GENERAL
TROUGHING THROUGHOUT THE REGION IN THE WAKE OF THE FILLING LOW WELL
OFF TO THE NORTH. GIVEN THE GOOD MODEL AGREEMENT WITH THE TIMING AND
MAGNITUDE OF THE MID LEVEL FEATURES HAVE FOLLOWED A GENERALLY MODEL
BLEND WITH A STRONG LEAN TOWARD THE HIGHER RESOLUTION NAM12.
SENSIBLE WEATHER WILL BE PRETTY STRAIGHT FORWARD THROUGH THE SHORT
TERM. A WARM EVENING WILL BE ENJOYED EAST KENTUCKY AS THE COLD FRONT
AND ITS ASSOCIATED SQUALL LINE PLODS TOWARD THE AREA. GRADIENT
WINDS WILL KEEP TEMPERATURES PROPPED UP FOR MOST SPOTS ALONG WITH AN
INCREASE IN THE CLOUDS LATER IN THE EVENING. DO NOT ANTICIPATE MUCH
IN THE WAY OF SHOWERS OR STORMS MAKING IT INTO EAST KENTUCKY BEFORE
MIDNIGHT...LIKELY SPARING ALL EVENING ACTIVITIES THROUGH THE AREA.
FOLLOWING SUNSET THE WINDS WILL LOSE A GOOD PORTION OF THEIR
GUSTINESS BUT STILL BE RATHER BREEZY DUE TO GRADIENT WINDS. THESE
SHOULD PICK UP AND BECOME GUSTY AGAIN LATER TONIGHT WITH THE PASSAGE
OF THE FRONT AND ANY SQUALL LINE ACTIVITY AHEAD OF IT. THE STORMS
WILL BE COMING THROUGH EAST KENTUCKY AT AN UNFAVORABLE TIME...LOSING
MUCH OF THE INSTABILITY WITH A PASSAGE IN THE DARK OF NIGHT. THIS IS
ALSO GOING TO BE PROGRESSIVE ENOUGH TO LIMIT THE HEAVY RAINS MAKING
FLOODING A LESSER CONCERN...DESPITE THE LOW FLASH FLOOD GUIDANCE. THE
FRONT MOVES EAST EARLY FRIDAY AND WILL BE TRAILED BY A FEW HOURS OF
SHOWERS. CAA WILL BE THE RULE WITH FALLING TEMPS EXPECTED THROUGH THE
DAY ON BRISK WEST WINDS. ALTHOUGH TEMPERATURES FRIDAY NIGHT WILL
BOTTOM OUT IN THE MID AND UPPER 30S...EXPECT ANY FROST THREAT TO BE
HINDERED BY LINGERING CLOUDS AND PROBABLY JUST ENOUGH WIND TO KEEP
THE AIR STIRRED.
FOLLOWED A BLEND OF THE MODEL DATA FOR TEMPERATURES THROUGH THE SHORT
TERM WITH A DIURNAL CURVE FROM THE NAM12 FAVORED. AS FOR POPS...HAVE
GONE HIGHER THAN ALL GUIDANCE EXPECTING MEASURABLE RAIN THROUGHOUT
ALL BUT THE FAR EASTERN PARTS OF THE AREA LATE TONIGHT...CATCHING THE
REST EARLY FRIDAY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 345 PM EDT THU APR 18 2013
THE EXTENDED PERIOD WILL START OUT DRY AND MILD...AS AN AREA OF HIGH
PRESSURE SETTLES OVER THE AREA. TEMPERATURES ON SATURDAY WILL LIKELY
ONLY MAKE IT INTO THE MID TO UPPER 50S ACROSS THE AREA...AS A COOLER
AIR MASS IS SLOWLY SCOURED OUT OF THE AREA. TEMPERATURES ON SUNDAY
WILL BE 5 TO 8 DEGREES WARMER...AS THE AIR MASS MODIFIES AND DRIES
OUT A BIT MORE. THE BEGINNING OF THE WORK WEEK WILL FEATURE MUCH
WARMER READINGS IN THE UPPER 60S ON MONDAY...AND AROUND 70 ON
TUESDAY...AS SOUTHERLY FLOW AHEAD OF AN APPROACHING WEATHER SYSTEM
INCREASES. THE CHANCE FOR RAIN WILL ARRIVE IN THE AREA LATE TUESDAY
EVENING...AS A COLD FRONT APPROACHES FROM THE WEST. THIS BOUNDARY
WILL MOVE ACROSS THE AREA TUESDAY NIGHT THROUGH WEDNESDAY
NIGHT...BRINGING WITH IT A VERY GOOD CHANCE FOR RAIN SHOWERS AND A
FEW THUNDERSTORMS. THE INSTABILITY WITH THIS SYSTEM APPEARS A BIT
MORE LIMITED...SO THUNDERSTORM ACTIVITY WILL LIKELY NOT BE AS
WIDESPREAD AS IT WAS WITH THIS WEEKS WEATHER SYSTEMS. ONCE THE FRONT
PASSES BY...YET ANOTHER COOL AND DRY AIR MASS WILL INVADE THE
AREA...BRINGING WITH IT COOLER TEMPERATURES AND PARTLY CLOUDY SKIES
LATE WEDNESDAY NIGHT AND THURSDAY. THE WEATHER DURING THE UPCOMING
WEEKEND WILL BE CALM AND PLEASANT. CLEAR SKIES AND LIGHT WINDS COULD
LEAD TO A RIDGE VALLEY TEMPERATURE SPLIT LATE SATURDAY NIGHT INTO
EARLY SUNDAY MORNING IN OUR DEEPER AND MORE SHELTERED NORTHEASTERN
VALLEYS. THE FORECAST WAS UPDATED TO AT LEAST BEGIN HINTING AT THIS
FEATURE...PARTICULARLY WITH SUPPORT FROM THE LATEST COOPMOS DATA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 135 AM EDT FRI APR 19 2013
VFR CONDITIONS WILL PREVAIL AT ALL SITES THROUGH 10 TO 12Z BEFORE
SHRA AND SCATTERED TO NUMEROUS TSRA ALONG...AND BEHIND...A COLD
FRONT ARRIVES AT SME AND LOZ FIRST...FOLLOWED BY JKL AND FINALLY WV
BORDER. AS SHRA AND TSRA ROLL THROUGH...AT LEAST PREVAILING MVFR AND
SOME POSSIBLE BRIEF IFR OR LOWER CIGS/VIS CAN BE ANTICIPATED. GUSTY
SOUTH WINDS MAY INCREASE AS THE FRONT AND ITS LINE OF EXPECTED
STORMS NEAR. THE BREEZY SOUTH WINDS ARE EXPECTED TO SHIFT TO THE
WEST BETWEEN 10Z AND 15Z IN THE WAKE OF THE FRONT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 8 AM EDT THIS MORNING FOR KYZ044-
050>052-058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...JP
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...DUSTY
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
1100 AM EDT FRI APR 19 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION FROM WEST TO EAST THIS
AFTERNOON AND EVENING. WIDESPREAD SHOWERS AND THUNDERSTORMS ARE
EXPECTED ALONG AND AHEAD OF THE BOUNDARY. CANADIAN HIGH PRESSURE
WILL BUILD INTO THE REGION LATE TONIGHT THROUGH SUNDAY...BRINGING
DRY AND COOL CONDITIONS. HIGH PRESSURE WILL REMAIN OVERHEAD EARLY
NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
14Z SURFACE OBSERVATIONS INDICATE COLD FRONT HAS REACHED FAR
EASTERN OH AND KY...AND WILL CROSS INTO WESTERN WV SOON. THE FRONT
WILL CONTINUE TO PUSH EASTWARD...AND IS STILL EXPECTED TO REACH
EASTERN WV BY EARLY AFTERNOON AND SWEEP ACROSS THE FORECAST AREA
FROM MID AFTERNOON THROUGH THIS EVENING.
THE PRESSURE GRADIENT BETWEEN THE APPROACHING COLD FRONT AND HIGH
PRESSURE OVER THE ATLANTIC CONTINUES TO INCREASE. WIND GUSTS
BETWEEN 15-20 MPH HAVE DEVELOPED OVER MOST OF THE FORECAST AREA.
WINDS WILL CONTINUE TO INCREASE THIS AFTERNOON WITH GUSTS UP TO 30
TO 35 MPH.
IN TERMS OF SEVERE THUNDERSTORM THREAT...12Z KIAD INDICATED A CAP
AROUND 700MB. HOWEVER...MODEL SOUNDINGS INDICATE THIS LAYER WILL
COOL BY A FEW DEGREES THIS AFTERNOON...WHILE DIURNAL SURFACE
HEATING CONTINUES. BIG VARIABLE WILL CONTINUE TO BE CLOUD COVER
AND ITS INFLUENCE ON INSTABILITY. FORECAST SOUNDINGS INDICATE
POTENTIAL FOR SOME BREAKS IN CLOUD COVER...AND THESE ARE BEING
OBSERVED IN PARTS OF WV AT THIS HOUR. THIS WOULD ENABLE CAPE TO
APPROACH 1000 J/KG OVER SOME LOCATIONS AT LEAST BRIEFLY. OTHERWISE
FORECAST IN ON TRACK FOR INCREASING MOISTURE DUE TO SOUTHERLY
FLOW AND A VERY STRONG JET OVER THE AREA WITH 50+KT WINDS ABOVE
850MB AHEAD OF THE FRONT. SPC HAS INCREASED SLIGHT RISK AREA TO
INCLUDE ALL OF THE FORECAST AREA FROM THE SHENANDOAH VALLEY
EWD...AND HI-RES MODELS LIKE THE HRRR INDICATE THE POTENTIAL FOR
AN ORGANIZED LINE OF SHOWERS/TSTMS TO DEVELOP AS THE FRONT
APPROACHES THIS AFTERNOON. ANY THUNDERSTORMS WILL HAVE POTENTIAL
TO TAP INTO THE STRONG WINDS ALOFT AND PRODUCE DAMAGING WINDS.
HODOGRAPHS ALSO INDICATE SOME POTENTIAL TORNADO RISK...ESPECIALLY
IF EMBEDDED SUPERCELLS DEVELOP WITH THE LINE OF THUNDERSTORMS.
THE COLD FRONT WILL MOVE OFF TO OUR EAST OVERNIGHT AND ANY
LEFTOVER SHOWERS WILL ALSO MOVE OUT OF OUR AREA. MIN TEMPS
OVERNIGHT WILL BE NOTICEABLY CHILLIER COMPARED TO RECENT
NIGHT...RANGING FROM THE 20S ALONG THE RIDGE TOPS IN THE POTOMAC
HIGHLANDS...TO THE MID AND UPPER 40S NEAR
WASHINGTON/BALTIMORE...TO THE LOWER 50S ACROSS SOUTHERN MARYLAND.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
HIPRES BLDS OVER THE RGN THIS WKND. WL BE IN CAA REGIME MOST OF THE
TIME...W/ NW/NLY FLOW SAT BCMG NE/ELY SUN AS CENTER OF HIGH HEADS
TWD NEW ENGLND/QUE. SHUD BE DIURNAL CU SAT...SPCLY IN THE MTNS. BY
SUN...SUBSIDENCE SHUD PREVAIL.
TEMPS WL BE BLO CLIMO SAT...AND DROP A CPL MORE BY SUN. LTST
MOS/GOING FCST IN GOOD AGREEMENT. GROWING SEASON HAS STARTED E OF
BLURDG. ALTHO IT WL BE CHILLY SAT NGT...A LGT NLY BRZ AS CURRENTLY
PROGGED WUD PRECLUDE EITHER FROST OR SUBFRZG TEMPS. RECENT TEMP BIAS
HAS BEEN TO FCST TOO COLD. WL OMIT FROM HWO ATTM AS POTL FOR
HEADLINE CONDS SLIM.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
MODEL GUIDANCE STILL INDICATING CAD SCENARIO DEVELOPING LATE IN THE
WEEKEND ONCE THE CENTER OF THE SFC HIGH SHIFTS EWD INTO SERN CANADA.
WEDGE OF COOLER AIR WILL SPILL SWD INTO THE MID-ATLANTIC REGION. THE
1040 MB HIGH WILL GRADUALLY PROGRESS EWD TOWARD THE CANADIAN
MARITIME...RESULTING IN ELY FLOW IN OUR AREA ERY NEXT WEEK. GIVEN
THE THE STILL COOL WATERS THIS TIME OF YR...CAD INVERSIONS ARE
DIFFICULT TO ERODE AND THUS HAVE THE POTENTIAL TO PERSIST FOR A
MULTI-DAY PERIOD ONCE AN OCEAN FETCH BECOMES ESTABLISHED. THIS MAY
BE THE CASE ERY NEXT WEEK. THE LATEST RUN OR TWO OF THE ECWMF...GFS
AND ITS ENSEMBLE MEAN SHOW AN INVERTED TROUGH DEVELOPING EAST OF
THIS CAD RIDGE BUT HAS BACKED OFF ON LOPRES DEVELOPMENT THAT TRACKS
CLOSE TO THE COAST. THUS KEPT MON-TUE FCST MAINLY DRY EXCEPT FOR LOW
CHANCE POPS NEAR THE CHSPK BAY. NONETHELESS...MARINE INFLUENCE WILL
RESULT IN CLOUDY CONDITIONS AND COOLER THAN NORMAL TEMPS.
COLD FRONT APPROACHES NEXT WED OR THU. STILL SOME UNCERTAINTY HOW
MUCH OF A WARMING TREND OCCURS MIDWEEK IN PRE-FRONTAL WARM SECTOR.
AS STATED ABOVE...CAD SETUP OFTEN TAKES LONGER TO ERODE...OFTEN
LONGER THAN MODELS INDICATE.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
MOSTLY MVFR CIGS LATE THIS MORNING. MODELS INDICATE POTENTIAL FOR
LOWER CLOUDS TO ERODE FOR A WHILE TODAY...SO AMENDMENTS UP TO VFR
AND POSSIBLE. SOUTHERLY WINDS WILL INCREASE WITH GUSTS AROUND 30
KNOTS EXPECTED.
A STRONG COLD FRONT WILL PASS THROUGH THE TERMINALS LATE THIS
AFTERNOON AND EVENING. A LINE OF HEAVY SHOWERS AND THUNDERSTORMS IS
EXPECTED ALONG AND AHEAD OF THE COLD FRONT. THUNDERSTORMS WILL BE
CAPABLE OF PRODUCING GUSTY WINDS. TAFS MAY NEED TO BE AMENDED
LATER TO ADJUST TIMING OF THESE SHOWERS/STORMS.
HIPRES OVR THE TERMINALS THIS WKND. NW WNDS SAT G20-25KT...BCMG NLY
AND DIMINISHING SAT NGT...AND VEERING ELY SUN.
ONSHORE FLOW DEVELOPS LATE IN THE WEEKEND AS HIPRES SHIFTS OFF THE
NEW ENGLAND COAST. THERE IS A POTENTIAL FOR AN EXTENDED PERIOD OF
LOW CLOUDS AND FOG ERY NEXT WEEK IF ONSHORE FLOW PERSISTS.
&&
.MARINE...
HAVE UPGRADED TO A GALE WARNING OVER ALL WATERS FROM 2PM TO 10PM.
SOUTHERLY WINDS ARE EXPECTED TO GRADUALLY INCREASE IN INTENSITY AS
THE PRESSURE GRADIENT INCREASES AHEAD OF AN APPROACHING COLD
FRONT. A LINE OF HEAVY SHOWERS AND THUNDERSTORMS IS EXPECTED ALONG
AND JUST AHEAD OF THE COLD FRONT. THE BEST CHANCE FOR THE HEAVIER
PRECIPITATION OVER THE WATERS WILL BE BETWEEN ABOUT 6 PM AND
MIDNIGHT. THUNDERSTORMS WILL BE CAPABLE OF PRODUCING GUSTY WINDS.
SPECIAL MARINE WARNINGS MAY BE NEEDED WITH THESE THUNDERSTORMS IF
WIND GUSTS REACH STORM FORCE.
THE COLD FRONT WILL MOVE OFF TO THE EAST LATE TONIGHT AND WINDS WILL
SHIFT TO THE NORTHWEST. SMALL CRAFT ADVISORIES WILL LIKELY BE
NEEDED AFTER THE GALE EXPIRES.
HIPRES BLDS ACRS THE WATERS THIS WKND. GOOD CAA SAT WL LEAD TO FVRBL
MOMENTUM TRANSFER AND RATHER HIGH MIXING HGTS. THIS WL PROMOTE 20-25
KT WNDS ACRS THE WATERS. HV ADDED SCA FOR ALL WATERS THRU 21Z. A
PRES SURGE MAY FLLW DOWN THE BAY SAT NGT.
BY SUN...THE SFC HIGH HEADS TWD NEW ENGLND...LEADING TO ELY FLOW ON
THE WATERS. WSPDS SHUD BE LIGHTER /UNDER SCA LVLS/. THE NELY/ELY
PTTN MAY LAST FOR A CPL DAYS.
&&
.TIDES/COASTAL FLOODING...
TIDAL ANOMALIES CURRENTLY RUNNING AROUND 1 OR 1.1 FEET LATE THIS
MORNING. AS NOTED IN EARLIER DISCUSSION...ANOMALIES WILL NEED TO
INCREASE MORE IN ORDER TO WARRANT A COASTAL FLOOD ADVISORY. WILL
CONTINUE TO MONITOR.
PREVIOUS DISCUSSION...
TIDAL DEPARTURES RUNNING BETWEEN A HALF-FT AND 1 FT
ABV ASTRO NORMS ATTM. A STIFF SLY FLOW ONGOING...WHICH WL ONLY
INCREASE TDA AHEAD OF APPROACHING CDFNT. THEREFORE...DO ANTICIPATE
DEPARTURES TO INCREASE FURTHER...WITH THE PM TIDE CYCLE THE ONE TO
WATCH. HOWEVER...WE/RE AT HALF- MOON...WHICH IS PROVIDING US WITH
SOME WIGGLE ROOM. DEPARTURES WILL NEED TO BE AROUND 1.5 FT FOR
MOST SITES TO REACH MINOR FLOOD THRESHOLDS. ANNAPOLIS MOST
SUSCEPTIBLE AT 1.2 FT. CBOFS /ADJUSTED FOR HIGH BIAS/ AND ESTOFS
BOTH SUGGEST THAT THE TIDE WL CREST ABOVE CAUTION STAGE BUT BELOW
MINOR FLOOD. FOR DC ...HEC-RAS ALSO SUGGESTS THAT THE TIDE WL BE
UNDER FLOOD STAGE. THEREFORE...WL BE WITHHOLDING ANY ADVISORIES AT
THIS TIME. HOWEVER...CONSIDERING MARGIN FOR ERROR...ITS CLOSE
ENOUGH TO WARRANT A CONTINUING MENTION IN HWO.
DEPARTURES SHOULD BE LOWER FOR THE AM CYCLE SAT...BUT BLOWOUT CONDS
MAY NOT BE REALIZED TIL LATE SAT-SAT NGT.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THIS AFTERNOON FOR
ANZ530>543.
GALE WARNING FROM 2 PM THIS AFTERNOON TO 10 PM EDT THIS
EVENING FOR ANZ530>543.
&&
$$
SYNOPSIS...BJL/KCS
NEAR TERM...BJL/KCS
SHORT TERM...HTS
LONG TERM...JRK
AVIATION...BJL/KCS/HTS
MARINE...JRK/BJL/KCS/HTS
TIDES/COASTAL FLOODING...HTS/KCS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
700 AM CDT FRI APR 19 2013
.UPDATED FOR 12Z AVIATION DISCUSSION...
ISSUED AT 643 AM CDT FRI APR 19 2013
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT FRI APR 19 2013
THE POWERFUL WINTER STORM THAT DUMPED OVER A FOOT OF SNOW IN SOME
LOCATIONS WILL EXIT THE REGION TODAY. LIGHT DEFORMATION SNOWFALL
WILL LINGER OVER THE EASTERN HALF OF THE CWA THIS MORNING...BUT THE
LARGE SCALE SUBSIDENCE ASSOCIATED WITH THE APPROACHING UPPER LEVEL
RIDGE WILL CLEAR SKIES OUT ACROSS THE WESTERN CWA. WATER VAPOR
IMAGERY DEPICTED A SHORTWAVE ON THE DOWNSTREAM AXIS OF THIS
AFOREMENTIONED UPPER LEVEL RIDGE...WITH SOME MID LEVEL CLOUDS ACROSS
THE WESTERN DAKOTAS. NUMERICAL MODELS HAVE THIS SHORTWAVE WEAKENING
WITH TIME...AND THE MID LEVEL CLOUDS DISSIPATING AS THEY DIVE
SOUTHWEST OF MINNESOTA. HOWEVER...FARTHER EAST WILL LIKELY SEE
SOME DIURNALLY DRIVEN RAIN/SNOW SHOWERS DEVELOP AS THE BOUNDARY
LAYER BECOMES DESTABILIZED THIS AFTERNOON WITH A FEW EMBEDDED
AREAS OF ENHANCED VORTICITY ROTATING AROUND THE PARENT CYCLONE
AIDING IN ASCENT. THIS IS DEPICTED WELL BY ALL 4 MEMBERS OF THE
HOPWRF ENSEMBLE. ANOTHER CONCERN IS STRONG SUSTAINED NORTHWEST
WINDS...WHICH MAY FLIRT WITH ADVISORY CRITERIA AT TIMES TODAY.
BUFR FORECAST SOUNDINGS VIA THE NAM...GFS...AND RAP ALL INDICATE
LOW TO MID 30KTS ATOP THE MIXED LAYER...WITH LAYER AVERAGED WINDS
IN THE UPPER 20S TO NEAR 30KTS. WE SHOULD BE ABLE TO MIX UP TO
850MB...BUT THE H850 WINDS DECREASE WITH TIME TODAY...SO THEREFORE
EXPECTING JUST BLUSTERY...NOT ADVISORY TYPE WINDS. HIGH PRESSURE
WILL CONTINUE TO BUILD ACROSS THE REGION TONIGHT WITH CLEARING
SKIES AND CALMING WINDS. THIS...COMBINED WITH THE FRESH
SNOWPACK...WILL SET THE STAGE FOR RECORD BREAKING LOW TEMPERATURES
BY SATURDAY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 405 AM CDT FRI APR 19 2013
SATURDAY BRINGS A BRIEF RESPITE IN PRECIPITATION AS SURFACE HIGH
PRESSURE ARRIVES. THE COOL WEATHER WILL PERSIST HOWEVER...AS
TEMPERATURES BARELY SNEAK ABOVE RECORD LOW VALUES FOR HIGHS. THIS
IS ILLUSTRATED BY THE FORECAST HIGH OF 40 AT MSP (WHERE THE RECORD
LOW HIGH TEMP FOR THE DATE IS 36) AND A FORECAST HIGH OF 37 AT
KSTC (WHERE THE RECORD LOW HIGH TEMP FOR THE DATE IS 35). BY LATE
SATURDAY AFTERNOON...A DECENT AREA OF 700-600MB OMEGA AND
INCREASING SATURATION IS EXPECTED TO SPREAD FROM WESTERN MN
EASTWARD ACROSS THE AREA. THIS SIGNALS THE TRANSITION TO AN ACTIVE
ZONAL FLOW REGIME...WITH THE SURFACE REFLECTION (IN THE FORM OF A
COLD FRONT) PROGGED TO PASS ACROSS THE REGION LATE SUNDAY INTO
MONDAY. WITH THERMAL PROFILES HOVERING AROUND 0C...WILL LIKELY SEE
A RAIN-SNOW MIX ON SATURDAY NIGHT AND SUNDAY MORNING...ALTHOUGH
ANY SNOW ACCUMULATIONS WOULD BE MINIMAL. BY SUNDAY
AFTERNOON...TEMPS WILL BE WARM ENOUGH TO YIELD RAIN. COULD ALSO
SEE SOME THUNDER IN CENTRAL/SOUTHERN MN ON SUNDAY AFTERNOON AS THE
FRONT AND LOW LEVEL TROUGH PASS...AS SUPPORTED BY SUB-ZERO GFS
BEST LI/S ATTENDANT WITH A 50-60 KT 900-850MB JET.
ON MONDAY AND TUESDAY...THE ASSOCIATED BAROCLINIC ZONE STALLS
JUST SOUTHEAST OF THE AREA...AND FOSTERS A PROLONGED PERIOD OF
LIGHT PRECIPITATION CHANCES FROM SOUTHERN MN INTO WEST CENTRAL
WI. WINTRY PRECIP WILL CONTINUE TO BE A POSSIBILITY...ESPECIALLY
DURING THE NOCTURNAL TIME FRAMES.
THURSDAY AND FRIDAY IS EXPECTED TO BRING MODERATING TEMPERATURES
AS HEIGHTS BUILD ACROSS THE REGION. BY FRIDAY...COULD SEE HIGHS
WELL INTO THE 50S...WITH 60S NOT OUT OF THE QUESTION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 643 AM CDT FRI APR 19 2013
LIGHT SNOW FROM THE DEPARTING STORM SYSTEM WILL LINGER ACROSS THE
WI/MN BORDER THIS MORNING...AND WILL SEE A FEW AFTERNOON RAIN/SNOW
SHOWERS DEVELOP AGAIN ACROSS WESTERN WISCONSIN. OTHERWISE HIGH
PRESSURE WILL BUILD ACROSS THE REGION AND ALREADY SEEING VFR
CONDITIONS ACROSS WESTERN MINNESOTA. NORTHWEST WINDS WILL PERSIST
TODAY...BUT TAPER OFF THIS EVENING WITH CLEAR SKIES EXPECTED
OVERNIGHT.
KMSP...
LOW VISBYS SHOULD IMPROVE RATHER QUICKLY THIS MORNING...AND BASED
ON CURRENT TRENDS ACROSS THE WEST SHOULD BE VFR BY LATER THIS
MORNING. COULD SEE A FEW AFTERNOON RAIN/SNOW SHOWERS...BUT
CONFIDENCE IN TIMING AND COVERAGE TOO LOW TO MENTION OTHER THAN
VCSH. SKIES WILL CLEAR OVERNIGHT WITH DECREASING WINDS.
/OUTLOOK FOR KMSP/
SAT...VFR WITH MVFR AND -RA LATE. WINDS SE AT 10G15KTS.
SUN...MVFR AND -RA WITH IFR AND TSRA POSSIBLE LATE. WINDS SSW AT
15G20KT.
MON...MVFR WITH IFR AND -RA POSSIBLE. WINDS SW EARLY...BECOMING NW
AT 10G15KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR MNZ043>045-
049>053-058>063-066>070-075-076.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR MNZ077-
078-084-085.
WI...WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR WIZ014.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR WIZ015-
016-023>025.
&&
$$
SHORT TERM...JRB
LONG TERM...LS
AVIATION...JRB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
405 AM CDT FRI APR 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT FRI APR 19 2013
THE POWERFUL WINTER STORM THAT DUMPED OVER A FOOT OF SNOW IN SOME
LOCATIONS WILL EXIT THE REGION TODAY. LIGHT DEFORMATION SNOWFALL
WILL LINGER OVER THE EASTERN HALF OF THE CWA THIS MORNING...BUT THE
LARGE SCALE SUBSIDENCE ASSOCIATED WITH THE APPROACHING UPPER LEVEL
RIDGE WILL CLEAR SKIES OUT ACROSS THE WESTERN CWA. WATER VAPOR
IMAGERY DEPICTED A SHORTWAVE ON THE DOWNSTREAM AXIS OF THIS
AFOREMENTIONED UPPER LEVEL RIDGE...WITH SOME MID LEVEL CLOUDS ACROSS
THE WESTERN DAKOTAS. NUMERICAL MODELS HAVE THIS SHORTWAVE WEAKENING
WITH TIME...AND THE MID LEVEL CLOUDS DISSIPATING AS THEY DIVE
SOUTHWEST OF MINNESOTA. HOWEVER...FARTHER EAST WILL LIKELY SEE
SOME DIURNALLY DRIVEN RAIN/SNOW SHOWERS DEVELOP AS THE BOUNDARY
LAYER BECOMES DESTABILIZED THIS AFTERNOON WITH A FEW EMBEDDED
AREAS OF ENHANCED VORTICITY ROTATING AROUND THE PARENT CYCLONE
AIDING IN ASCENT. THIS IS DEPICTED WELL BY ALL 4 MEMBERS OF THE
HOPWRF ENSEMBLE. ANOTHER CONCERN IS STRONG SUSTAINED NORTHWEST
WINDS...WHICH MAY FLIRT WITH ADVISORY CRITERIA AT TIMES TODAY.
BUFR FORECAST SOUNDINGS VIA THE NAM...GFS...AND RAP ALL INDICATE
LOW TO MID 30KTS ATOP THE MIXED LAYER...WITH LAYER AVERAGED WINDS
IN THE UPPER 20S TO NEAR 30KTS. WE SHOULD BE ABLE TO MIX UP TO
850MB...BUT THE H850 WINDS DECREASE WITH TIME TODAY...SO THEREFORE
EXPECTING JUST BLUSTERY...NOT ADVISORY TYPE WINDS. HIGH PRESSURE
WILL CONTINUE TO BUILD ACROSS THE REGION TONIGHT WITH CLEARING
SKIES AND CALMING WINDS. THIS...COMBINED WITH THE FRESH
SNOWPACK...WILL SET THE STAGE FOR RECORD BREAKING LOW TEMPERATURES
BY SATURDAY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 405 AM CDT FRI APR 19 2013
SATURDAY BRINGS A BRIEF RESPITE IN PRECIPITATION AS SURFACE HIGH
PRESSURE ARRIVES. THE COOL WEATHER WILL PERSIST HOWEVER...AS
TEMPERATURES BARELY SNEAK ABOVE RECORD LOW VALUES FOR HIGHS. THIS
IS ILLUSTRATED BY THE FORECAST HIGH OF 40 AT MSP (WHERE THE RECORD
LOW HIGH TEMP FOR THE DATE IS 36) AND A FORECAST HIGH OF 37 AT
KSTC (WHERE THE RECORD LOW HIGH TEMP FOR THE DATE IS 35). BY LATE
SATURDAY AFTERNOON...A DECENT AREA OF 700-600MB OMEGA AND
INCREASING SATURATION IS EXPECTED TO SPREAD FROM WESTERN MN
EASTWARD ACROSS THE AREA. THIS SIGNALS THE TRANSITION TO AN ACTIVE
ZONAL FLOW REGIME...WITH THE SURFACE REFLECTION (IN THE FORM OF A
COLD FRONT) PROGGED TO PASS ACROSS THE REGION LATE SUNDAY INTO
MONDAY. WITH THERMAL PROFILES HOVERING AROUND 0C...WILL LIKELY SEE
A RAIN-SNOW MIX ON SATURDAY NIGHT AND SUNDAY MORNING...ALTHOUGH
ANY SNOW ACCUMULATIONS WOULD BE MINIMAL. BY SUNDAY
AFTERNOON...TEMPS WILL BE WARM ENOUGH TO YIELD RAIN. COULD ALSO
SEE SOME THUNDER IN CENTRAL/SOUTHERN MN ON SUNDAY AFTERNOON AS THE
FRONT AND LOW LEVEL TROUGH PASS...AS SUPPORTED BY SUB-ZERO GFS
BEST LI/S ATTENDANT WITH A 50-60 KT 900-850MB JET.
ON MONDAY AND TUESDAY...THE ASSOCIATED BAROCLINIC ZONE STALLS
JUST SOUTHEAST OF THE AREA...AND FOSTERS A PROLONGED PERIOD OF
LIGHT PRECIPITATION CHANCES FROM SOUTHERN MN INTO WEST CENTRAL
WI. WINTRY PRECIP WILL CONTINUE TO BE A POSSIBILITY...ESPECIALLY
DURING THE NOCTURNAL TIME FRAMES.
THURSDAY AND FRIDAY IS EXPECTED TO BRING MODERATING TEMPERATURES
AS HEIGHTS BUILD ACROSS THE REGION. BY FRIDAY...COULD SEE HIGHS
WELL INTO THE 50S...WITH 60S NOT OUT OF THE QUESTION.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1117 PM CDT THU APR 18 2013
SNOW TAPERING IN INTENSITY TO THE EAST THE NEXT HOUR OR SO. SHOULD
LIFT TO MVFR CIGS LATER TONIGHT FROM WEST TO EAST ACROSS MN
AREA...LITTLE LATER INTO WISCONSIN. LIGHT SNOW/FLURRIES INTO MID
MORNING IN THE EAST OTHERWISE MVFR CIGS BECOMING VFR INTO MN AND
BY EARLY EVENING IN WESTERN WI. NORTHWEST WINDS REMAIN STRONG AND
GUSTY AS THE SYSTEM LIFTS OFF TO THE NORTHEAST...DIMINISHING BY
EVENING MOST AREAS.
KMSP...SNOW TAPERING IN INTENSITY THROUGH THE EARLY
MORNING...WITH MAINLY FLURRIES AFTER 11Z OR SO. THIS SHOULD END IN
THE MORNING WITH CIGS LIFTING AND REMAINING MVFR INTO THE
AFTERNOON. SHOULD BREAK OUT LATE WITH GUSTY NORTHWEST WINDS DIMINISHING
AFTER 00Z SAT.
/OUTLOOK FOR KMSP/
SAT...VFR WITH MVFR AND -RA POSSIBLE LATE. WINDS SE AT 10G15KTS.
SUN...MVFR WITH IFR AND -RA POSSIBLE. WINDS S AT 10G15KTS.
MON...MVFR OR LOWER WITH -RA POSSIBLE. WINDS BCMG NNW 10G20KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR MNZ041>045-
047>070-073>076-082-083-091.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR MNZ077-
078-084-085-092.
WI...WINTER STORM WARNING UNTIL 10 AM CDT THIS MORNING FOR WIZ014.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR WIZ015-
016-023>025.
&&
$$
SHORT TERM...JRB
LONG TERM...LS
AVIATION...DWE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1118 PM CDT THU APR 18 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 249 PM CDT THU APR 18 2013
IMPRESSIVE DEFORMATION SNOW EVENT WELL UNDERWAY...WITH STRONG FGEN
NOTED IN THE H8-H5 LAYER. SEEING CONVECTIVE ELEMENTS COMING UP OUT
OF IOWA...WHICH IS AN INDICATION OF THE INSTABILITY PRESENT...WITH
SEVERAL HEAVY BANDS OF SNOW NOTED ON RADAR AS A RESULT. HAVE
GOTTEN REPORTS OF AROUND 2 INCHES PER HOUR OUT IN WRN MN THIS
AFTERNOON...AND EXPECT THESE SORTS OF RATES TO CONTINUE THROUGH
THE AFTERNOON.
THROUGH TONIGHT...FOLLOWED THE RAP FAIRLY CLOSELY FOR FORECAST
UPDATES TODAY...AS IT HAS HAD A PRETTY GOOD HANDLE ON HOW THINGS
HAVE UNFOLDED ALL DAY. AS A RESULT...BOOSTED SNOW TOTALS SOME
WITHIN THE HEART OF THE BAND FROM REDWOOD FALLS UP THROUGH ST.
CLOUD...WITH 6 INCH AMOUNTS CREEPING EAST TO BE ACROSS THE EAST
END OF THE WARNING COUNTIES NOW...WITH SNOW TOTAL AT MINNEAPOLIS
INCREASED FROM AROUND 3 INCHES TO 6 INCHES. IF THE RAP WERE TO BE
BELIEVED /WHICH BASED ON REPORTS SEEN SO FAR...DO NOT SEE WHY IT
CAN NOT BE/...THEN WE WILL LIKELY END UP WITH A BAND OF 10 TO 12
INCHES FROM GRANITE FALLS OVER TO NEW ULM AND UP TO LONG PRAIRIE
OVER TO MORA. WITH UPDATES MADE TO FORECAST TODAY...DID ADD TODD
COUNTY TO THE WARNING AND COULD HAVE VERY EASILY ADDED
STEVENS AND DOUGLAS COUNTIES OUT WEST...ALONG WITH ANOTHER ROW OF
COUNTIES TO THE EAST OF THE WARNING THAT WOULD INCLUDE THE REST OF
THE TWIN CITIES. IN FACT...AS OF THE WRITING OF THIS...THINKING
WE WILL GO AHEAD AND EXPAND THE WARNING EAST AND WEST WHEN DONE
WITH THIS AFD TO INCLUDE ALL OF THE TWIN CITIES METRO AREA.
HEAVY SNOW WILL START LETTING UP AFTER 21Z SW OF THE MN
RIVER...BETWEEN 0Z AND 3Z ALONG I-94 FROM THE TWIN CITIES UP
THROUGH ST. CLOUD...WITH HEAVY SNOW PULLING OUT OF THE NRN CWA
SHORTLY AFTER 06Z. LIGHT SNOW WILL CONTINUE THROUGH TONIGHT...WITH
LIGHT SNOW SHOWERS CONTINUING THROUGH THE DAY ACROSS WRN
WI ON FRIDAY...THOUGH MAJORITY OF ACCUMULATIONS WILL BE COMING
NOW THROUGH 12Z FRIDAY. FOR FRIDAY...ANY ADDITIONAL ACCUMULATIONS
WILL BE UNDER AN INCH.
AT 230 PM...THE RAIN/SNOW LINE WAS LOCATED NEAR AN ALBERT LEA
THROUGH RICE LAKE LINE...AND AGAIN GENERALLY FOLLOWED THE
RAP...WITH ALL SNOW FINALLY BREAKING OUT IN THE EAU CLAIRE AREA
AROUND 3Z.
AS FOR TEMPERATURES...CLOUD COVER AND NW WINDS WILL RESULT IN
FAIRLY STEADY TEMPERATURES THROUGH FRIDAY...WITH LOWS TONIGHT
FALLING BACK INTO THE UPPER 20S/LOWER 30S WHILE HIGHS ON FRIDAY
STAY MIRED IN THE 30S...OR ABOUT 20 DEGREES BELOW NORMAL.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 PM CDT THU APR 18 2013
SHORT DRY WINDOW WILL BE ENCOUNTERED ACROSS MUCH OF THE FA
FRIDAY NIGHT INTO MUCH OF SUNDAY AS 1025MB HIGH PRESSURE DOME
SETTLES OVER THE REGION. COPIOUS AMOUNTS OF RESIDUAL MOISTURE
FROM CURRENT SNOWSTORM COUPLED WITH RADIATIONAL
COOLING...LIGHT WINDS...SHOULD PORTEND SCT TO AREAS OF FOG
OVER MUCH OF THE CWA BETWEEN 20/06Z-20/13Z. ONLY FLY IN THE
OINTMENT WOULD BE ADVECTION OF MID TO HIGH LEVEL CLD DECK
ASSOCIATED WITH NEXT SYSTEM ENTERING FAR EASTERN MONTANA
AND WYOMING.
RAMPED UP POPS SLIGHTLY FOR SAT EVE-TUE AFTN STORM EVENT.
WEAK SFC CYCLONE ASSOCIATED WITH SAME WILL TREK FROM SE
MONTANA SUNDAY AFTN TO NE NEBRASKA BY MON/12Z. ALTHOUGH
PASSAGE OF INVERTED TROUGH AND SFC SYSTEM INTO EASTERN
WI WILL OCCUR BY LATE MONDAY NIGHT...50H TROF WILL DIG
INTO WESTERN MN BY TUE/12Z...AND THEN FINALLY MARCH THROUGH
EASTERN CWA BY EARLY WEDNESDAY MORNING. USED GFS40 FOR
ALL OF LONG TERM FORECAST CONSIDERING CURRENT EXCELLENT
HANDLING OF SNOW EVENT. BEST THETA E ADVECTION COUPLET
NOTED OVER MUCH OF CENTRAL CWA AND INTO WEST CENTRAL
WI AROUND SUN/12Z TIME PERIOD. COUPLET DEGRADES SOMEWHAT
DURING THE DAY ON SUNDAY WITH BEST THETA E ADVECTION STILL
NOTED OVER WEST CENTRAL WI. 295K ISENTROPIC ANAL INDICATES
BEST PCPN CHANCES ACROSS MUCH OF REGION LATE SAT NIGHT INTO
EARLY SUN AFTN. LUCKILY 850 TEMPS SHOULD BE WARM ENOUGH FOR
MAINLY A LIQUID PCPN EVENT THROUGH MONDAY AFTN. COULD BE A
SHORT WINDOW OF FREEZING RAIN SUN 06-12Z OVER A NARROW SWATH OF
FA 30 MILES EITHER SIDE OF A LINE FROM AXN TO ANOKA. TEMPS
ALOFT WILL PRODUCE A MAINLY LIGHT SNOW EVENT MONDAY EVENING
AND INTO TUESDAY. BEFORE THIS OCCURS HOWEVER...COULD SEE
A FEW ISOLATED THUNDERSTORMS ACROSS EXTREME SOUTHERN MN
MONDAY AFTN ASSOCIATED WITH NEAR NEGATIVE LI`S.
ANOTHER WEAK SURFACE TROF INDICATED TO SWEEP THROUGH THE
FA WED NIGHT THROUGH EARLY THU. BEST FORCING INDICATED
MAINLY OVER WEST CENTRAL WI. NOT MUCH FOR POPS AND ATMOSPHERIC
COLUMN AGAIN POINTS TO A RAIN SNOW MIX FOR THIS SHORT EVENT.
ONE GOOD NOTE FOR FORECAST CONCERNS WARMING TREND FOR AFTN
HIGHS WED-THU. LOOK FOR TEMPS RAMPING UP INTO THE UPPER 40S TO
MID 50S BOTH DAYS..WHICH IS MORE IN TUNE WITH NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1117 PM CDT THU APR 18 2013
SNOW TAPERING IN INTENSITY TO THE EAST THE NEXT HOUR OR SO. SHOULD
LIFT TO MVFR CIGS LATER TONIGHT FROM WEST TO EAST ACROSS MN
AREA...LITTLE LATER INTO WISCONSIN. LIGHT SNOW/FLURRIES INTO MID
MORNING IN THE EAST OTHERWISE MVFR CIGS BECOMING VFR INTO MN AND
BY EARLY EVENING IN WESTERN WI. NORTHWEST WINDS REMAIN STRONG AND
GUSTY AS THE SYSTEM LIFTS OFF TO THE NORTHEAST...DIMINISHING BY
EVENING MOST AREAS.
KMSP...SNOW TAPERING IN INTENSITY THROUGH THE EARLY
MORNING...WITH MAINLY FLURRIES AFTER 11Z OR SO. THIS SHOULD END IN
THE MORNING WITH CIGS LIFTING AND REMAINING MVFR INTO THE
AFTERNOON. SHOULD BREAK OUT LATE WITH GUSTY NORTHWEST WINDS DIMINISHING
AFTER 00Z SAT.
/OUTLOOK FOR KMSP/
SAT...VFR WITH MVFR AND -RA POSSIBLE LATE. WINDS SE AT 10G15KTS.
SUN...MVFR WITH IFR AND -RA POSSIBLE. WINDS S AT 10G15KTS.
MON...MVFR OR LOWER WITH -RA POSSIBLE. WINDS BCMG NNW 10G20KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 10 AM CDT FRIDAY FOR MNZ041>045-
047>070-073>076-082-083-091.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT FRIDAY FOR MNZ077-078-084-
085-092.
WI...WINTER STORM WARNING UNTIL 10 AM CDT FRIDAY FOR WIZ014.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT FRIDAY FOR WIZ015-016-
023>025.
&&
$$
SHORT TERM...MPG
LONG TERM...AJZ
AVIATION...DWE
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1233 PM CDT FRI APR 19 2013
.UPDATE...
ISSUED AT 1115 AM CDT FRI APR 19 2013
CENTER OF POWERFUL STORM SYSTEM THAT HAS IMPACTED US WITH TSRA THE
PAST COUPLE OF DAYS NOW ENTERING WRN LAKE SUPERIOR AND CONTINUES
TO MOVE NE. A DEEP TROF EXISTS OVER THE CNTRL CONUS IN THE WAKE OF
THIS STORM AND HAS GIVEN US OUR RATHER CHILLY MORNING. THERE IS
ANOTHER REASONABLY STRONG VORT MAX OVER SRN SD SLIDING DOWN THE
BACKSIDE OF THIS TROF HEADING OUR WAY...TO THE SE. EXTENSIVE AREA
OF SC CLOUDS EXISTS OVER MUCH OF THE BI-STATE REGION WITH THE
BACKEDGE HAVING MOVED THRU CNTRL MO. HOWEVER...AND AS EXPECTED...
THIS BACKEDGE HAS BECOME MORE DIFFUSE OVER THE PAST HOUR AS
DIURNAL INFLUENCES HAVE BEGUN TO KICK IN WITH STRONG APRIL SUN AND
THIS SHOULD SERVE TO SLOW DOWN THE CLEARING WITH ADDITIONAL CLOUDS
ON THIS EDGE. TEMPS REMAIN WELL BELOW AVERAGE AT 16Z/11AM...WITH
READINGS IN THE UPR 30S AND LO 40S...W SFC WNDS ARE GUSTING TO
30-35MPH.
MAIN FCST PROBLEM WILL BE IMPACT OF THE SHORTWAVE HEADING OUR WAY
LATER TODAY. NEW 12Z MODELS AS WELL AS LATEST RAP AND HRRR ALL
TAKE THE HEART OF THIS VORT MAX AND ITS ASSOCIATED H300 SPEED MAX
THRU CNTRL MO AND SRN IL...AND WITH THE CYCLONIC CURVATURE AT
THE BASE OF THE TROF...WILL CURL THE BEST LIFT ASSOCIATED WITH
THESE FEATURES ON ITS LEFT FLANK...OR FOR PARTS OF THE NRN AND
NERN FA. THERE WILL ALSO BE SLIGHTLY BETTER LO LEVEL CONVERGENCE
SETTING UP IN THOSE AREAS AS WELL. SO IF ANYTHING IS GOING TO
HAPPEN...IT LOOKS LIKE MAINLY W-CNTRL AND PARTS OF SW IL. VERY
MARGINAL MOISTURE AND INSTABILITY SHOULD LIMIT PCPN TO SHRA AND
WILL PROBABLY BE ISOLD AT BEST. 20PCT POPS THUS STILL LOOK
JUSTIFIED BUT HAVE SHIFTED THE TIMING BACK FOR LATE THIS AFTERNOON
INSTEAD OF EARLIER IN THE DAY. SOME PCPN...IF IT DEVELOPS...MAY
EVEN LAST BRIEFLY PAST 00Z.
OTHERWISE...TEMPS AND WINDS LOOK ON TARGET...WITH MAXES IN THE
45-50 RANGE...OR ALMOST 20F BELOW AVERAGE...AND GUSTY W SFC WNDS
30-35MPH.
TES
&&
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 350 AM CDT FRI APR 19 2013
CENTER OF INTENSE STORM SYSTEM WILL BE SPINNING ITS WAY FROM THE
UPPER GREAT LAKES INTO SOUTHERN CANADA TODAY. THIS PUTS THE FA IN
THE WINDY AND COLD WAKE OF THE SYSTEM...WHICH MEANS TODAYS WEATHER
WILL BE CHARACTERIZED BY STRONG WEST-NORTHWEST WINDS AND TEMPS THAT
WILL BE WELL BELOW NORMAL.
EXTENSIVE SC DECK BLANKETS THE REGION EARLY TODAY...AND RAGGED BACK
EDGE OF THE CLOUDS RUNS FROM W IA TO NEAR THE MO/KS BORDER AT 08Z.
AS LOW CONTINUES TO PULL AWAY FROM THE AREA BELIEVE THAT THE BACK
EDGE OF THE CLOUD DECK WILL SWEEP EAST. SOMEWHAT OFFSETTING THIS
CLEARING SHOULD BE DIURNAL CLOUD DEVELOPMENT DUE TO THE COLD TEMPS
AND AMPLE LOW LEVEL MOISTURE...AND OUR N/NE COUNTIES SHOULD SEE MORE
COVERAGE OF THESE HOME-GROWN CLOUDS DUE TO SOMEWHAT DEEPER CYCLONIC
CURVATURE OVER THIS PART OF THE CWA.
MOS GUIDANCE FOR MAX TEMPS LOOKS TO BE IN THE BALLPARK. VALUES ARE
SUPPORTED BY CONDITIONAL CLIMATOLOGY WHICH SUGGESTS A 10-18 DEGREE
WARMUP...AND ALSO DOVETAILS FAIRLY WELL WITH MAX TEMPS DERIVED FROM
THE PROGGED 850MB TEMPS AND THE THINKING THAT AT LEAST PARTIAL
SUNSHINE WILL ALLOW SOME ADDITIONAL WARMING.
TRUETT
.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 350 AM CDT FRI APR 19 2013
(TONIGHT THROUGH SUNDAY NIGHT)
MAIN ISSUE FOR TONIGHT WILL BE WHEN WILL CLOUDS CLEAR OUT AND HOW
COLD WILL IT GET. AS SYSTEM CONTINUES TO LIFT TO NORTHEAST THROUGH
SOUTHERN CANADA TONIGHT...WE CONTINUE TO BE IN WRAP AROUND FLOW WITH
GUSTY WEST TO NORTHWEST WINDS DIMINISHING BY 06Z. BUT WITH SO MUCH
LOW LEVEL MOISTURE DUE TO MAJOR RAINFALL PAST 36 HOURS...NOT SURE
HOW CONFIDENT I AM ABOUT FROST/FREEZE POTENTIAL. BUT WITH STUFF
BUDDING OUT OVER REGION...SKIES CLEARING OUT/WIND DIMINISHING AND LOWS
FORECAST IN THE UPPER 20S TO LOW 30S...WILL ERR ON SIDE OF CAUTION
AND ISSUE A FREEZE WARNING FOR FAR NORTHERN 6 COUNTIES AND FROST
ADVISORY FOR THE REMAINDER OF THE FORECAST AREA FROM 06Z TO 13Z
TONIGHT.
BEYOND THAT QUIET WEATHER IN STORE FOR THE WEEKEND WITH TEMPERATURES
MODERATING THROUGH THE PERIOD. HIGHS ON SATURDAY WILL BE IN THE MID
50S TO LOW 60S. LOWS SATURDAY NIGHT WILL BE WARMER...ONLY IN THE
UPPER 30S TO MID 40S. HIGHS WARMING UP INTO THE MID 60S EVERYWHERE
ON SUNDAY WITH LOWS SUNDAY NIGHT IN THE MID 40S...AHEAD OF NEXT
WEATHER SYSTEM.
(MONDAY THROUGH THURSDAY)
EXTENDED MODELS CONTINUE TO HAVE DIFFERENCES ON STRENGTH AND TIMING
OF NEXT WEATHER SYSTEM THAT WILL BEGIN TO AFFECT THE FORECAST AREA
ON MONDAY. FOR NOW HAVE SHOWERS AND THUNDERSTORMS MOVING INTO FAR
NORTHERN PORTIONS OF FORECAST AREA ON MONDAY. THEN SHOWERS AND
THUNDERSTORMS TO INCREASE IN COVERAGE MONDAY NIGHT THROUGH
TUESDAY...BEFORE TAPERING OFF FROM WEST TO EAST ON TUESDAY NIGHT.
TEMPERATURES TO REMAIN NEAR NORMAL ON MONDAY IN THE MID TO UPPER
60S...THEN DROP OFF INTO THE LOW TO MID 50S BY WEDNESDAY AS SURFACE
RIDGE BUILDS IN. COOL OFF NOT TO LAST LONG AS TEMPERATURES BEGIN TO
MODERATE ON THURSDAY...WARMING UP INTO THE UPPER 50S TO LOW 60S.
BYRD
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1233 PM CDT FRI APR 19 2013
VFR CONDITIONS WILL PREVAIL AREAWIDE THRU THE VALID TAF PERIOD.
CIGS OVER MUCH OF THE AREA WILL GIVE WAY TO CLEARING THIS EVENING
WITH HI CIGS RETURNING ON SATURDAY. GUSTY W SFC WNDS WILL DIMINISH
SIGNIFICANTLY THIS EVENING WITH LOSS OF HEATING AND APPROACH OF HI
PRES AND LIGHT WINDS TO THEN CONTINUE INTO SATURDAY. OUTSIDE CHC
OF -SHRA OR SPRINKLES LATER THIS AFTERNOON OR EARLY THIS EVENING
WITH UPPER LEVEL DISTURBANCE MOVING THRU AT THAT TIME...BUT PERFER
TO SEE RADAR RETURNS FIRST ON SUCH LO PROB SITUATIONS.
SPECIFICS FOR KSTL...VFR THRU THE PERIOD...GUSTY W SFC WNDS THIS
AFTERNOON BECOMING LIGHT W-NW THIS EVENING AND CONTINUING INTO
SATURDAY. POTENTIAL OF SOME SPRINKLES LATER THIS AFTERNOON AND
EARLY EVENING BUT WILL LEAVE OUT UNTIL WE SEE SOME RADAR RETURNS
AND CONFIDENCE INCREASES.
TES
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...FROST ADVISORY FROM 1 AM TO 8 AM CDT SATURDAY FOR AUDRAIN MO-
BOONE MO-CALLAWAY MO-COLE MO-CRAWFORD MO-FRANKLIN MO-
GASCONADE MO-IRON MO-JEFFERSON MO-LINCOLN MO-MADISON MO-
MONITEAU MO-MONROE MO-MONTGOMERY MO-OSAGE MO-PIKE MO-RALLS
MO-REYNOLDS MO-ST. CHARLES MO-ST. FRANCOIS MO-ST. LOUIS
CITY MO-ST. LOUIS MO-STE. GENEVIEVE MO-WARREN MO-WASHINGTON
MO.
FREEZE WARNING FROM 1 AM TO 8 AM CDT SATURDAY FOR KNOX MO-LEWIS
MO-MARION MO-SHELBY MO.
IL...FROST ADVISORY FROM 1 AM TO 8 AM CDT SATURDAY FOR BOND IL-
CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-JERSEY IL-
MACOUPIN IL-MADISON IL-MARION IL-MONROE IL-MONTGOMERY IL-
PIKE IL-RANDOLPH IL-ST. CLAIR IL-WASHINGTON IL.
FREEZE WARNING FROM 1 AM TO 8 AM CDT SATURDAY FOR ADAMS IL-BROWN
IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1115 AM CDT FRI APR 19 2013
.UPDATE...
ISSUED AT 1115 AM CDT FRI APR 19 2013
CENTER OF POWERFUL STORM SYSTEM THAT HAS IMPACTED US WITH TSRA THE
PAST COUPLE OF DAYS NOW ENTERING WRN LAKE SUPERIOR AND CONTINUES
TO MOVE NE. A DEEP TROF EXISTS OVER THE CNTRL CONUS IN THE WAKE OF
THIS STORM AND HAS GIVEN US OUR RATHER CHILLY MORNING. THERE IS
ANOTHER REASONABLY STRONG VORT MAX OVER SRN SD SLIDING DOWN THE
BACKSIDE OF THIS TROF HEADING OUR WAY...TO THE SE. EXTENSIVE AREA
OF SC CLOUDS EXISTS OVER MUCH OF THE BI-STATE REGION WITH THE
BACKEDGE HAVING MOVED THRU CNTRL MO. HOWEVER...AND AS EXPECTED...
THIS BACKEDGE HAS BECOME MORE DIFFUSE OVER THE PAST HOUR AS
DIURNAL INFLUENCES HAVE BEGUN TO KICK IN WITH STRONG APRIL SUN AND
THIS SHOULD SERVE TO SLOW DOWN THE CLEARING WITH ADDITIONAL CLOUDS
ON THIS EDGE. TEMPS REMAIN WELL BELOW AVERAGE AT 16Z/11AM...WITH
READINGS IN THE UPR 30S AND LO 40S...W SFC WNDS ARE GUSTING TO
30-35MPH.
MAIN FCST PROBLEM WILL BE IMPACT OF THE SHORTWAVE HEADING OUR WAY
LATER TODAY. NEW 12Z MODELS AS WELL AS LATEST RAP AND HRRR ALL
TAKE THE HEART OF THIS VORT MAX AND ITS ASSOCIATED H300 SPEED MAX
THRU CNTRL MO AND SRN IL...AND WITH THE CYCLONIC CURVATURE AT
THE BASE OF THE TROF...WILL CURL THE BEST LIFT ASSOCIATED WITH
THESE FEATURES ON ITS LEFT FLANK...OR FOR PARTS OF THE NRN AND
NERN FA. THERE WILL ALSO BE SLIGHTLY BETTER LO LEVEL CONVERGENCE
SETTING UP IN THOSE AREAS AS WELL. SO IF ANYTHING IS GOING TO
HAPPEN...IT LOOKS LIKE MAINLY W-CNTRL AND PARTS OF SW IL. VERY
MARGINAL MOISTURE AND INSTABILITY SHOULD LIMIT PCPN TO SHRA AND
WILL PROBABLY BE ISOLD AT BEST. 20PCT POPS THUS STILL LOOK
JUSTIFIED BUT HAVE SHIFTED THE TIMING BACK FOR LATE THIS AFTERNOON
INSTEAD OF EARLIER IN THE DAY. SOME PCPN...IF IT DEVELOPS...MAY
EVEN LAST BRIEFLY PAST 00Z.
OTHERWISE...TEMPS AND WINDS LOOK ON TARGET...WITH MAXES IN THE
45-50 RANGE...OR ALMOST 20F BELOW AVERAGE...AND GUSTY W SFC WNDS
30-35MPH.
TES
&&
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 350 AM CDT FRI APR 19 2013
CENTER OF INTENSE STORM SYSTEM WILL BE SPINNING ITS WAY FROM THE
UPPER GREAT LAKES INTO SOUTHERN CANADA TODAY. THIS PUTS THE FA IN
THE WINDY AND COLD WAKE OF THE SYSTEM...WHICH MEANS TODAYS WEATHER
WILL BE CHARACTERIZED BY STRONG WEST-NORTHWEST WINDS AND TEMPS THAT
WILL BE WELL BELOW NORMAL.
EXTENSIVE SC DECK BLANKETS THE REGION EARLY TODAY...AND RAGGED BACK
EDGE OF THE CLOUDS RUNS FROM W IA TO NEAR THE MO/KS BORDER AT 08Z.
AS LOW CONTINUES TO PULL AWAY FROM THE AREA BELIEVE THAT THE BACK
EDGE OF THE CLOUD DECK WILL SWEEP EAST. SOMEWHAT OFFSETTING THIS
CLEARING SHOULD BE DIURNAL CLOUD DEVELOPMENT DUE TO THE COLD TEMPS
AND AMPLE LOW LEVEL MOISTURE...AND OUR N/NE COUNTIES SHOULD SEE MORE
COVERAGE OF THESE HOME-GROWN CLOUDS DUE TO SOMEWHAT DEEPER CYCLONIC
CURVATURE OVER THIS PART OF THE CWA.
MOS GUIDANCE FOR MAX TEMPS LOOKS TO BE IN THE BALLPARK. VALUES ARE
SUPPORTED BY CONDITIONAL CLIMATOLOGY WHICH SUGGESTS A 10-18 DEGREE
WARMUP...AND ALSO DOVETAILS FAIRLY WELL WITH MAX TEMPS DERIVED FROM
THE PROGGED 850MB TEMPS AND THE THINKING THAT AT LEAST PARTIAL
SUNSHINE WILL ALLOW SOME ADDITIONAL WARMING.
TRUETT
.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 350 AM CDT FRI APR 19 2013
(TONIGHT THROUGH SUNDAY NIGHT)
MAIN ISSUE FOR TONIGHT WILL BE WHEN WILL CLOUDS CLEAR OUT AND HOW
COLD WILL IT GET. AS SYSTEM CONTINUES TO LIFT TO NORTHEAST THROUGH
SOUTHERN CANADA TONIGHT...WE CONTINUE TO BE IN WRAP AROUND FLOW WITH
GUSTY WEST TO NORTHWEST WINDS DIMINISHING BY 06Z. BUT WITH SO MUCH
LOW LEVEL MOISTURE DUE TO MAJOR RAINFALL PAST 36 HOURS...NOT SURE
HOW CONFIDENT I AM ABOUT FROST/FREEZE POTENTIAL. BUT WITH STUFF
BUDDING OUT OVER REGION...SKIES CLEARING OUT/WIND DIMINISHING AND LOWS
FORECAST IN THE UPPER 20S TO LOW 30S...WILL ERR ON SIDE OF CAUTION
AND ISSUE A FREEZE WARNING FOR FAR NORTHERN 6 COUNTIES AND FROST
ADVISORY FOR THE REMAINDER OF THE FORECAST AREA FROM 06Z TO 13Z
TONIGHT.
BEYOND THAT QUIET WEATHER IN STORE FOR THE WEEKEND WITH TEMPERATURES
MODERATING THROUGH THE PERIOD. HIGHS ON SATURDAY WILL BE IN THE MID
50S TO LOW 60S. LOWS SATURDAY NIGHT WILL BE WARMER...ONLY IN THE
UPPER 30S TO MID 40S. HIGHS WARMING UP INTO THE MID 60S EVERYWHERE
ON SUNDAY WITH LOWS SUNDAY NIGHT IN THE MID 40S...AHEAD OF NEXT
WEATHER SYSTEM.
(MONDAY THROUGH THURSDAY)
EXTENDED MODELS CONTINUE TO HAVE DIFFERENCES ON STRENGTH AND TIMING
OF NEXT WEATHER SYSTEM THAT WILL BEGIN TO AFFECT THE FORECAST AREA
ON MONDAY. FOR NOW HAVE SHOWERS AND THUNDERSTORMS MOVING INTO FAR
NORTHERN PORTIONS OF FORECAST AREA ON MONDAY. THEN SHOWERS AND
THUNDERSTORMS TO INCREASE IN COVERAGE MONDAY NIGHT THROUGH
TUESDAY...BEFORE TAPERING OFF FROM WEST TO EAST ON TUESDAY NIGHT.
TEMPERATURES TO REMAIN NEAR NORMAL ON MONDAY IN THE MID TO UPPER
60S...THEN DROP OFF INTO THE LOW TO MID 50S BY WEDNESDAY AS SURFACE
RIDGE BUILDS IN. COOL OFF NOT TO LAST LONG AS TEMPERATURES BEGIN TO
MODERATE ON THURSDAY...WARMING UP INTO THE UPPER 50S TO LOW 60S.
BYRD
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 705 AM CDT FRI APR 19 2013
EXTENSIVE AREA OF COLD AIR SC CONTINUES TO BLANKET FA EARLY
TODAY...BUT BACK EDGE OF CLOUD DECK CONTINUES TO PUSH EAST AND IS
NOW APPROXIMATELY 85 MI W OF KCOU. EXPECT THIS EDGE TO CONTINUE
PUSHING EAST...BUT ALSO ANTICIPATE THAT DIURNAL CU WILL BEGIN TO
FORM NO LATER THAN MID MORNING AND WILL AT LEAST PARTIALLY OFFSET
A LINEAR WEST TO EAST CLEARING TREND ACROSS THE AREA.
THEREFORE...EXPECT CURRENT HIGH END MVFR/LOW END VFR OVC TO
GRADUALLY TRANSITION TO A SCT-BKN VFR DECK 4-6KFT BETWEEN MID
MORNING AND EARLY AFTERNOON...WITH ALL CLOUDS DISSIPATING THIS
EVENING WITH LOSS OF HEATING. WEST WINDS WILL REMAIN QUITE
GUSTY...WITH DEEP MIXING ALLOWING GUSTS AROUND 30 KTS. SKIES
SHOULD QUICKLY CLEAR AND WINDS WILL RAPIDLY DIMINISH BY EARLY THIS
EVENING AS DAYTIME HEATING IS LOST.
DUE TO THE WATERLOGGED GROUND...WILL NEED TO KEEP AN EYE ON FOG
POTENTIAL TONIGHT...ESPECIALLY IN LOW LYING AREAS SUCH AS SUS.
SPECIFICS FOR KSTL...CLOUDS AOA 3KFT SHOULD BE THE RULE FOR MUCH
OF THE DAY...ALTHOUGH CERTAINLY EXPECT CURRENT OVC TO TRANSITION
TO A BKN-SCT TYPE COVERAGE BY AROUND MIDDAY. STRONG WEST WINDS
WILL BE GUSTING TO AROUND 30 KTS BY LATE MORNING AND INTO THE
EARLY PART OF THE AFTERNOON. LOSS OF DIURNAL HEATING SHOULD ALLOW
SKIES TO QUICKLY CLEAR AND WINDS TO QUICKLY SUBSIDE DURING THE
EARLY EVENING HOURS.
TRUETT
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...FROST ADVISORY FROM 1 AM TO 8 AM CDT SATURDAY FOR AUDRAIN MO-
BOONE MO-CALLAWAY MO-COLE MO-CRAWFORD MO-FRANKLIN MO-
GASCONADE MO-IRON MO-JEFFERSON MO-LINCOLN MO-MADISON MO-
MONITEAU MO-MONROE MO-MONTGOMERY MO-OSAGE MO-PIKE MO-RALLS
MO-REYNOLDS MO-ST. CHARLES MO-ST. FRANCOIS MO-ST. LOUIS
CITY MO-ST. LOUIS MO-STE. GENEVIEVE MO-WARREN MO-WASHINGTON
MO.
FREEZE WARNING FROM 1 AM TO 8 AM CDT SATURDAY FOR KNOX MO-LEWIS
MO-MARION MO-SHELBY MO.
IL...FROST ADVISORY FROM 1 AM TO 8 AM CDT SATURDAY FOR BOND IL-
CALHOUN IL-CLINTON IL-FAYETTE IL-GREENE IL-JERSEY IL-
MACOUPIN IL-MADISON IL-MARION IL-MONROE IL-MONTGOMERY IL-
PIKE IL-RANDOLPH IL-ST. CLAIR IL-WASHINGTON IL.
FREEZE WARNING FROM 1 AM TO 8 AM CDT SATURDAY FOR ADAMS IL-BROWN
IL.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1204 AM CDT FRI APR 19 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 339 PM CDT THU APR 18 2013
MORNING UPPER AIR ANALYSIS INDICATES A LONGWAVE TROUGH EXTENDING
FROM SOUTH CENTRAL CANADA INTO THE PLAINS...WITH RIDGING OVER THE
EASTERN AND WESTERN CONUS. MID AND UPPER LEVEL JET ENERGY EXTENDS
SOUTH/SOUTHEAST ACROSS THE WESTERN CONUS...EAST ACROSS THE
SOUTHWESTERN CONUS AND SOUTHERN PLAINS...AND THEN NORTHEAST ACROSS
THE PLAINS AND UPPER MISSISSIPPI VALLEY. WATER VAPOR IMAGERY
INDICATES PLENTY OF MID LEVEL MOISTURE EXTENDING FROM THE SOUTHERN
PLAINS INTO THE OHIO RIVER VALLEY. A MID LEVEL DRY INTRUSION IS
EVIDENT FROM WEST TEXAS INTO EASTERN KANSAS AND PORTIONS OF MISSOURI
AND IOWA. THERE ALSO APPEARS TO BE AN AREA OF ENHANCED
VORTICITY...EMBEDDED WITHIN THE LONGWAVE TROUGH...OVER EASTERN
NEBRASKA. FINALLY...AN AXIS OF MID LEVEL DEFORMATION IS APPARENT
EXTENDING FROM THE UPPER MISSISSIPPI VALLEY...SOUTHWEST INTO THE
CENTRAL PLAINS. AT THE SURFACE AN AREA OF LOW BAROMETRIC PRESSURE IS
NOTED OVER EASTERN IOWA...WITH A COLD FRONT EXTENDING
SOUTH/SOUTHWEST ACROSS THE MISSISSIPPI VALLEY. THE LOW LEVEL WIND
FIELD ACROSS OUR AREA REMAINS FROM THE NORTHWEST AS A RESULT.
THE AFOREMENTIONED AXIS OF MID LEVEL DEFORMATION CONTINUES TO
PRESENT LIGHT SNOW TO PORTIONS OF EASTERN NEBRASKA THIS
AFTERNOON...BUT THIS ACTIVITY HAS CLEARED OUR AREA TO THE EAST FOR
THE MOST PART AND LITTLE IN THE WAY OF SNOWFALL IS BEING OBSERVED
ACROSS OUR AREA. IN ADDITION...A STRONG LOW LEVEL PRESSURE GRADIENT
CONTINUES TO PROMOTE A STRONG LOW LEVEL WIND FIELD ACROSS OUR AREA
THIS AFTERNOON. GUIDANCE FROM THE NAM...OPERATIONAL
GFS...EC...SREF-MEAN AND RAP HOWEVER ALL SUGGEST THE LOW LEVEL PRESSURE
GRADIENT WILL WEAKEN LATE THIS AFTERNOON INTO THIS EVENING...THUS
RESULTING IN DECREASING WIND SPEEDS AT THE SURFACE. GIVEN ALL
THIS...IMPROVING CONDITIONS SHOULD BE OBSERVED ACROSS THE AREA
THROUGH THE REST OF THIS AFTERNOON AND THIS EVENING AND AS A
RESULT...THE REMAINDER OF THE WINTER WEATHER ADVISORY HAS BEEN
CANCELLED.
AN OVERALL LACK IN KINEMATIC FORCING IS EXPECTED THROUGH AT LEAST
MIDDAY SATURDAY AND AS A RESULT...DRY CONDITIONS ARE EXPECTED THROUGH 18Z
SATURDAY. BY SATURDAY AFTERNOON HOWEVER...AN ~80KT MID LEVEL JET
STREAK IS EXPECTED TO MOVE ACROSS PORTIONS OF THE PLAINS AND
MISSOURI RIVER VALLEY. THE RIGHT-REAR QUADRANT OF THIS STREAK IS
EXPECTED TO SET UP SHOP OVER NORTHEASTERN PORTIONS OF OUR CWA...THUS
POTENTIALLY PROMOTING ENOUGH OF A THERMALLY-DIRECT CIRCULATION FOR
PRECIPITATION PRODUCTION. IN ADDITION TO THE SYNOPTIC-SCALE
LIFT...FORECAST PROXIMITY SOUNDINGS FROM ACROSS OUR AREA...PER THE
NAM AND OPERATIONAL GFS...SUGGEST STEEP LOW LEVEL LAPSE RATES DURING
THE AFTERNOON HOUR MAY PROMOTE UP TO 100J/KG OF POTENTIAL
INSTABILITY WITH MINIMAL CIN. ALTHOUGH LOWER TROPOSPHERIC MOISTURE
IS NOT EXPECTED TO BE ALL THAT GREAT DURING THE DAY SATURDAY...THERE
MAY BE JUST ENOUGH FORCING FOR A FEW SPRINKLES TO BE REALIZED AT THE
SURFACE. GIVEN ALL THIS...WENT AHEAD WITH SPRINKLES ACROSS ROUGHLY
THE NORTHEASTERN HALF OF OUR CWA STARTING 18Z SATURDAY.
CLEARING SKIES AND WEAK SURFACE RIDGING SHOULD PROVIDE A COLD NIGHT
ACROSS THE AREA TONIGHT...WITH LOW TEMPERATURES IN THE LOW TO MID
20S FORECAST FOR MOST LOCATIONS. PLENTY OF DIABATIC HEATING...ALONG
WITH A STRONG AND PERSISTENT DOWN-SLOPING LOW LEVEL WIND
FIELD...SHOULD PROVIDE A WARMER DAY ON SATURDAY...WITH AFTERNOON
HIGH TEMPERATURES IN THE 50S FORECAST FOR MOST LOCATIONS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 339 PM CDT THU APR 18 2013
PATTERN: OTHER THAN A BRIEF BREAK LAST WEEKEND WE/VE BEEN IN A COLD
WET PATTERN SINCE APR 9TH. WE/LL SEE A REPEAT OF THIS REPRIEVE...
IMPROVING TEMPORARILY THIS WEEKEND BEFORE THE LAST MAJOR COLD PLUNGE
IN THIS CURRENT PATTERN. THEREAFTER ENSEMBLES CONTINUE TO INDICATE A
PATTERN CHANGE WITH REORIENTATION OF THE LONG-WAVE CONFIGURATION.
THE CUT-OFF LOW CURRENTLY UNDER THE N PAC REX BLOCK WILL HEAD E...
SHOVING THE E PAC RIDGE INTO THE WRN USA.
MONTHLY TEMP THUS FAR: AS OF MIDNGT GRI IS SITTING AT AN AVERAGE
TEMP OF 43.6F. THIS IS 4.6F BELOW NORMAL. THE LAST APRIL THAT WAS
THIS COLD WAS 1983...WHICH INCLUDED ALL 30 DAYS.
ALOFT: THE SHORT-WAVE /SHRTWV/ TROF OVER THE PAC NW AT 00Z/SAT WILL
MOVE THRU SAT-SAT NGT. THIS TROF WILL BEGIN CARVING OUT THE NEXT
LGWV TROF. THE NEXT MORE POTENT SHRTWV TROF DELIVERS THE CANADIAN
COLD. THIS LAST BLAST IS FORCED BY HGT RISES APPROACHING THE W
COAST. TUE LOOKS LIKE THE COLDEST DAY.
SFC: HIGH PRES HEADS E SAT WHILE LOW PRES TRACKS ACROSS SRN CANADA.
ITS POTENT COLD FRONT WILL MOVE THRU HERE SOMETIME MON. THEN CHILLY
HIGH PRES SETTLES IN TUE-WED. A REINFORCING SHOT OF BELOW NORMAL
CHILL COULD PROVIDE A GLANCING BLOW THU...BUT TEMPS WILL STILL BE
HEADING UP. THEN FRI ITS BACK TO NORMAL /60S TO NEAR 70F/.
HAZARDS: THERE COULD BE MULTIPLE THUNDER THREATS EARLY NEXT
SUN-MON. PERIOD OF NEAR ADVISORY MATERIAL WINDS. THERE IS ALSO A
VERY LOW PROBABILITY FOR MINOR ACCUMULATING SNOW FOR PARTS OF THE
FCST AREA...ESPECIALLY IF IT COINCIDES WITH NIGHTTIME HRS MON NGT.
UPCOMING PCPN OPPORTUNITIES: MULTIPLE EVENTS OF VARYING MAGNITUDE
SAT-MON. FOR NOW LOOKS LIKE THE NEXT POTENTIALLY MODERATE PCPN EVENT
IS SLATED FOR MON NGT-TUE MRNG BUT THIS IS SUBJECT TO CHANGE.
THE DAILY DETAILS...
FRI NGT: WARM FRONT DEVELOPS AND LIFTS THRU. LOSS OF FRI AFTN`S
INSTABILITY WILL BRING AN END TO THE THREAT OF SPRINKLES.
SAT: DRY FOR MOST OF THE FCST AREA. ELEVATED MIXED LAYER /EML/
ADVECTS IN AS WINDS BACK IN THE 900-700 MB LAYER. THIS WILL STABILIZE
SFC PARCELS. LOW-LVL MSTR WILL NOT BE ENTRAINED ENUF FOR MID-LVL
INSTABILITY.
THIS TROF WILL BE MUCH MORE BROAD SUN-MON VS THE ONE MOVING THRU
ATTM. SO TRYING TO PIN DOWN ANY SENSIBLE WX AND ITS IMPACTS IS
TOUGH. FOR SURE WE KNOW THE PRIMARY FORCING MECHANISM WILL BE THE
COLD FRONTAL PASSAGE /CFP/ MON MRNG. THE GFS ENSEMBLE CLUSTERING FOR
0.5" QPF IN 24 HRS OCCURS 06Z/MON-06Z/TUE...ESSENTIALLY SUN NGT THRU
MON NGT.
MSTR RETURN WILL BE A PROBLEM WITH THIS MULTI-DAY SYSTEM. THE SYSTEM
CURRENTLY AFFECTING THE ERN USA WILL SWEEP THE HIGHEST QUALITY MSTR
FAR S INTO THE GULF. SO INSTABILITY WILL BE MODEST. PRESENT
INDICATIONS ARE THAT DWPTS OF 50F WON/T ARRIVE UNTIL MON AFTN OVER
OUR FAR SE COUNTIES. EC OFFERS SBCAPE OF 500 J/KG. SO NO SVR TSTMS
ARE EXPECTED.
MON: EARLY MRNG CFP. DAILY HIGH TEMPS MIGHT OCCUR BTWN MIDNGT AND 7
AM. STRONG CAA RESULTS IN FALLING TEMPS. HOWEVER...SUGGEST USING MON
TEMPS WITH CAUTION. THERE IS UNCERTAINTY IN TIMING OF FROPA. SOME
MID-LVL INSTABILITY MAY REMAIN ABOVE THE FRONTAL SFC AND/OR AHEAD OF
THE FRONT IF ITS PASSAGE IS DELAYED.
MON-TUE: H8 TEMPS ARE FCST 2 STANDARD DEVIATIONS BELOW NORMAL! GFS
ENSEMBLE MEAN HAS -4C H8 ISOTHERM INTO N-CNTRL KS AT 12Z/TUE.
IF TUE ENDS UP CLOUDY...WE COULD BREAK THE RECORD FOR THE COLDEST
HIGH TEMP EVER OBSERVED ON APR 23RD. THIS ISN/T IN THE BAG BECAUSE
WE/RE STILL SEE DISAGREEMENT ON WHEN THE BEST CHANCE FOR PCPN FALLS.
IF IT ENDS UP TUE AS THE 00Z EC/GEM SUGGEST...HIGH TEMPS IN THE 30S
ARE PROBABLE. NOT READY TO GO THERE YET BUT IT/S ON THE TABLE.
DON/T LOSE HEART. THE NAEFS 8-14 DAY TEMP OUTLOOK /WHICH INCLUDES
ALL THE CANADIAN-GFS ENSEMBLE MEMBERS/ INDICATES NEAR NORMAL TEMPS.
HOWEVER...AFTER THU 4/25 TEMPS MAY ACTUALLY HEAD TO THE OTHER SIDE
OF THE SCALE...AVERAGING AT OR ABOVE NORMAL TO CLOSE OUT THE
MONTH.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1154 PM CDT THU APR 18 2013
AN UPPER LOW PRESSURE SYSTEM CONTINUED TO EXIT TO THE CENTRAL
PLAINS TO THE EAST...AND THE CENTER OF THE LOW WAS IN EASTERN MN
EARLY TONIGHT. SKIES WERE CLEARING IN SUBSIDENCE BEHIND THE
DEPARTING SYSTEM AND FOR THE MOST PART...KGRI SHOULD JUST SEE
SCATTERED VFR CLOUDS DURING THE OVERNIGHT HOURS. CLOUDS INCREASE
AGAIN ON FRIDAY AS CONVECTIVE TEMPS ARE REACHED AND A JET STREAK
AND SHEARED SHORTWAVE ENERGY TRANSLATE SOUTHEAST IN THE NORTHWEST
FLOW REGIME. SPRINKLES OR HIT OR MISS RAIN SHOWERS ARE POSSIBLE IN
THE AFTN BUT HAVE NOT INCLUDED IN TAF DUE TO THE ISOLATED NATURE
OF THE EXPECTED ACTIVITY. DIURNALLY DRIVEN CLOUD COVER IS EXPECTED
TO DECREASE FRIDAY EVENING WITH SUNSET. WINDS WILL BE STEADY FM THE NW
ON FRIDAY WITH GUSTS AROUND 25KTS POSSIBLE AS FORECAST SOUNDINGS
INDICATE MIXING NEAR H75. WIND SPEEDS SUBSIDE AND BECOME FAIRLY
LIGHT/VARIABLE FRIDAY EVENING IN RELAXING GRADIENT UNDER INFLUENCE
OF SUBTLE SFC RIDGING ALONG THE MISSOURI RIVER.
&&
.CLIMATE...
ISSUED AT 339 PM CDT THU APR 18 2013
GRI AND HSI WILL SET THE RECORDS FOR THE COLDEST HIGH TEMPS EVER
RECORDED FOR THIS DATE. EXPECT THE RECORD EVENT REPORTS /RER/ TO
POST AROUND OR SHORTLY AFTER 530 PM.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...BRYANT
LONG TERM...HALBLAUB
AVIATION...FAY
CLIMATE...HALBLAUB
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1221 PM EDT FRI APR 19 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST FROM THE GREAT LAKES TODAY AND WILL MOVE
ACROSS THE NORTH COUNTRY TONIGHT...BRINGING GUSTY SOUTHERLY WINDS
AND RAIN SHOWERS AND POSSIBLE THUNDERSTORMS LATE THIS AFTERNOON
AND TONIGHT. MUCH COOLER WEATHER WILL BE OVER THE REGION ON SATURDAY.
A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION SATURDAY NIGHT AND
WILL REMAIN OVER THE NORTH COUNTRY THROUGH MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1221 PM EDT FRIDAY...MINOR UPDATES TO T/TD/MAX T NUMBERS
THROUGH EARLY EVENING BASED OFF CURRENT OBSERVATONAL DATA AND
LATEST LAMP/RAP DATA. OTHERWISE NO OTHER APPRECIABLE ADJUSTMENTS
NEEDED ATTM. PRIOR DISCUSSION FOLLOWS...
A VERY WINDY AND MILD DAY STILL ON TAP WITH MODEST UPDATES TO
TEMPS/WIND/WIND GUSTS AND POPS THROUGH THE EVENING HOURS TO ACCT
FOR CURRENT AND EXPECTED TRENDS. BASED OFF MOST RECENT RAP/NAM12
MIXED LAYER SOUNDINGS AND CURRENT OBSERVATIONAL DATA HAVE GONE
AHEAD AND ISSUED A WIND ADVISORY FROM THE CHAMPLAIN VALLEY WEST
INTO OUR NRN NY COUNTIES THROUGH THIS EVENING FOR
SOUTH/SOUTHWESTERLY GUSTS INTO THE 45 TO 55 MPH RANGE. ALREADY
HAVE RECEIVED ISOLATED TREE/POWER OUTAGE REPORTS EITHER FROM LAST
NIGHT OR THIS MORNING...AND EXPECTED MORE OF THE SAME TODAY/THIS
EVENING AS PRE- FRONTAL P-GRAD REMAINS TIGHT AND PBL DEEPENS (SEE
OUR LATEST REPORTS). STILL EXPECTING THE FRONTAL BOUNDARY TO
ARRIVE INTO OUR FAR WESTERN COUNTIES BY LATE THIS AFTERNOON...AND
INTO VT TOWARD SUNSET. STRONG ANAFRONTAL SIGNATURE WITH THIS
FEATURE WITH PRIMARY RAIN SHIELD BEHIND THE WIND SHIFT.
INDEED...AN INCREDIBLY TIGHT 925 MB THERMAL GRADIENT ALONG THE
FRONT WITH VALUES DROPPING FROM +18C TO +5C IN A MATTER OF 50 NM
OR SO. THIS TYPE OF FORCING MAY LEAD TO SHALLOW CONVECTIVE FINE-
LINE DEVELOPMENT ACROSS OUR NRN NY/CHAMPLAIN VALLEY COUNTIES RIGHT
ALONG THE SFC BOUNDARY BEFORE WEAKENING AS IT PROGRESSES INTO ERN
VT AS SUGGESTED BY THE HRRR DATA. WITH SUCH WIND IN THE
PBL...UPDRAFT STRENGTH AND LIGHTNING THREAT LIKELY MINIMAL...BUT
AN ENHANCED CONVECTIVE WIND THREAT MAY AT LEAST BE PLAUSIBLE
SHOULD SUCH A FEATURE DEVELOP. TIME WILL TELL. OVERALL RAIN
AMOUNTS GENERALLY IN THE 0.33 TO 0.75 INCH RANGE WITH CUSTOMARY
VARIATION...ESPECIALLY GIVEN STRONG FLOW AND LOCALIZED
OROGRAPHICAL EFFECTS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
AS OF 458 AM EDT FRIDAY...THE COLD FRONT WILL MOVE THROUGH THE
REGION TONIGHT. HAVE GONE WITH LIKELY TO CATEGORICAL POPS FOR RAIN
SHOWERS TONIGHT. MUCH COOLER TEMPERATURES WILL BE OVER THE REGION
ON SATURDAY WITH HIGHS FROM THE UPPER 40S TO LOWER 50S. THERE WILL
BE A SLIGHT CHANCE FOR SOME RAIN SHOWERS OVER THE HIGHER
ELEVATIONS OF THE ADIRONDACKS AND GREEN MOUNTAINS ON SATURDAY. A
RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION SATURDAY NIGHT
AND SUNDAY...WITH LOWS SATURDAY NIGHT IN THE TEENS AND 20S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 512 AM EDT FRIDAY...SFC RIDGE NEARBY ON SUNDAY NIGHT INTO
MONDAY AND ASSOCIATED DEEP DRY LAYER WL RESULT IN MAINLY CLR
SKIES. PROGGED 85H TEMPS BTWN -2C AND -4C SUPPORT HIGHS IN THE
M40S NEK/MTNS TO M50S CPV/SLV. STILL PLENTY OF UNCERTAINTY FOR
TUESDAY AND BEYOND WITH REGARDS TO POTENTIAL COASTAL SYSTEM ON
TUESDAY AND ANOTHER GREAT LAKES CUTTER ON THURS. LATEST 00Z ECMWF
SHOWS SFC LOW PRES DEVELOPING ACRS SNE ON TUES...AS 5H S/W ENERGY
TRACKS ACRS OUR FA. ECWMF SHOWS BEST 850 TO 500MB RH JUST TOO OUR
EAST...ALONG WITH NO CLOSED 5H/7H CIRCULATION...THEREFORE FEEL
IMPACT TO OUR CWA WL BE LIMITED. WL CONT TO MENTION LOW CHC POPS.
TEMPS WL BE COOL WITH PROGGED 85H TEMPS NEAR 0C...AND LIMITED
MIXING FROM CLOUDS...THINKING MAINLY 40S EASTERN/CENTRAL VT/MTNS AND
L/M 50S ELSEWHERE. BOTH GFS/ECMWF CONTS TO SUPPORT AN ACTIVE
PATTERN WITH ANOTHER SYSTEM IMPACTING OUR FA LATE WEDS INTO THURS.
STILL SOME UNCERTAINTY WITH REGARDS TO TIMING OF MOISTURE/QPF AND
EXACT STORM TRACK. LATEST TRENDS SHOW SFC LOW PRES TRACKING TO OUR
WEST...WITH GUSTY SOUTHERLY WINDS DEVELOPING ON WEDS AFTN INTO
THURS...VERY SIMILAR TO THE SYSTEM TODAY. GIVEN EXPECTED TRACK TO
OUR WEST...ANTICIPATE OUR CWA WL BE IN THE WARM SECTOR WITH MUCH
ABOVE NORMAL TEMPS POSSIBLE WEDS INTO THURSDAY...ALONG WITH A
BRIEF 3 TO 6 HR WINDOW OF SHOWERS. WL TREND TWD ABOVE NORMAL TEMPS
AND MENTION CHC POPS ATTM. AS THE EVENT BECMG CLOSER...WL FINE
TUNE TEMPS/POP TIMING...ALONG WITH QPF AMOUNTS.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
THROUGH 12Z SATURDAY...GUSTY SOUTHERLY WINDS WL CONT TODAY AT ALL
TAF SITES...ALONG WITH A 3 TO 5 HR WINDOW OF SHOWERS AND POTENTIAL
MVFR CONDITIONS. CRNT SFC ANALYSIS SHOWS A TIGHT PRES GRADIENT
CONTS BTWN SFC LOW PRES OVER THE NORTHERN GREAT LAKES AND HIGH
PRES ACRS THE NORTH ATLANTIC. THIS WL CREATE SFC WIND GUSTS BTWN
30 AND 35 KNTS TODAY...ALONG WITH AREAS OF MODERATE LLVL
TURBULENCE. GIVEN THE LACK OF MIXING AT MPV/RUT HAVE MENTION LLVL
WS THRU 15Z. OTHERWISE...BAND OF RAIN SHOWERS WL IMPACT MSS BTWN
20-24Z TODAY...AND INTO THE CPV BY 00Z...AND EAST AND SOUTH OF
MPV/RUT BY 06Z TONIGHT. EXPECT A 3 TO 5 HR WINDOW OF MODERATE RAIN
WITH MVFR CIGS/VIS LIKELY. A WIND SHIFT TO THE WEST/SOUTHWEST IS
ANTICIPATED BY 06Z BEHIND SFC COLD FRNT. COOLER AND BREEZY
CONDITIONS WL CONT AFT 06Z...WITH MAINLY VFR CONDITIONS.
OUTLOOK 12Z SATURDAY THROUGH TUESDAY...GUSTY WINDS WL SLOWLY
DECREASE ON SATURDAY...WITH SFC HIGH PRES BUILDING INTO OUR TAF
SITES. VFR CONDITIONS WL PREVAIL THRU MONDAY...WITH SOME INCREASE
IN CLOUDS AND CHCS OF PREICP BY MONDAY NIGHT INTO
TUESDAY...ESPECIALLY MPV/RUT.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...WIND ADVISORY UNTIL 11 PM EDT THIS EVENING FOR VTZ001-002-005-
009-011.
NY...WIND ADVISORY UNTIL 11 PM EDT THIS EVENING FOR NYZ026>031-034-
035-087.
&&
$$
SYNOPSIS...WGH
NEAR TERM...JMG
SHORT TERM...WGH
LONG TERM...TABER
AVIATION...TABER
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1016 AM EDT FRI APR 19 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE EAST FROM THE GREAT LAKES TODAY AND WILL MOVE
ACROSS THE NORTH COUNTRY TONIGHT...BRINGING GUSTY SOUTHERLY WINDS
AND RAIN SHOWERS AND POSSIBLE THUNDERSTORMS LATE THIS AFTERNOON
AND TONIGHT. MUCH COOLER WEATHER WILL BE OVER THE REGION ON SATURDAY.
A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION SATURDAY NIGHT AND
WILL REMAIN OVER THE NORTH COUNTRY THROUGH MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1016 AM EDT FRIDAY...A VERY WINDY AND MILD DAY STILL ON TAP
WITH MODEST UPDATES TO TEMPS/WIND/WIND GUSTS AND POPS THROUGH THE
EVENING HOURS TO ACCT FOR CURRENT AND EXPECTED TRENDS. BASED OFF
MOST RECENT RAP/NAM12 MIXED LAYER SOUNDINGS AND CURRENT
OBSERVATIONAL DATA HAVE GONE AHEAD AND ISSUED A WIND ADVISORY FROM
THE CHAMPLAIN VALLEY WEST INTO OUR NRN NY COUNTIES THROUGH THIS
EVENING FOR SOUTH/SOUTHWESTERLY GUSTS INTO THE 45 TO 55 MPH RANGE.
ALREADY HAVE RECEIVED ISOLATED TREE/POWER OUTAGE REPORTS EITHER
FROM LAST NIGHT OR THIS MORNING...AND EXPECTED MORE OF THE SAME
TODAY/THIS EVENING AS PRE- FRONTAL P-GRAD REMAINS TIGHT AND PBL
DEEPENS (SEE OUR LATEST REPORTS). STILL EXPECTING THE FRONTAL
BOUNDARY TO ARRIVE INTO OUR FAR WESTERN COUNTIES BY LATE THIS
AFTERNOON...AND INTO VT TOWARD SUNSET. STRONG ANAFRONTAL SIGNATURE
WITH THIS FEATURE WITH PRIMARY RAIN SHIELD BEHIND THE WIND SHIFT.
INDEED...AN INCREDIBLY TIGHT 925 MB THERMAL GRADIENT ALONG THE
FRONT WITH VALUES DROPPING FROM +18C TO +5C IN A MATTER OF 50 NM
OR SO. THIS TYPE OF FORCING MAY LEAD TO SHALLOW CONVECTIVE FINE-
LINE DEVELOPMENT ACROSS OUR NRN NY/CHAMPLAIN VALLEY COUNTIES RIGHT
ALONG THE SFC BOUNDARY BEFORE WEAKENING AS IT PROGRESSES INTO ERN
VT AS SUGGESTED BY THE HRRR DATA. WITH SUCH WIND IN THE
PBL...UPDRAFT STRENGTH AND LIGHTNING THREAT LIKELY MINIMAL...BUT
AN ENHANCED CONVECTIVE WIND THREAT MAY AT LEAST BE PLAUSIBLE
SHOULD SUCH A FEATURE DEVELOP. TIME WILL TELL. OVERALL RAIN
AMOUNTS GENERALLY IN THE 0.33 TO 0.75 INCH RANGE WITH CUSTOMARY
VARIATION...ESPECIALLY GIVEN STRONG FLOW AND LOCALIZED
OROGRAPHICAL EFFECTS. PRIOR DISCUSSION FOLLOWS...
SURFACE PRESSURE GRADIENT WILL REMAIN TIGHT ACROSS THE REGION
TODAY...WITH SOUTHERLY SURFACE WIND GUSTS UP TO 45 MPH POSSIBLE
THIS AFTERNOON. THIS IS JUST BELOW WIND ADVISORY CRITERIA.
EXPECTING A MAINLY DRY DAY TODAY WITH SOME PARTLY SUNNY
SKIES...AND TEMPERATURES CLIMBING INTO THE LOWER 70S. THE BEST
CHANCE FOR RAIN SHOWERS WILL BE LATE THIS AFTERNOON ACROSS THE
SAINT LAWRENCE VALLEY AND THE ADIRONDACKS IN NORTHERN NEW YORK
...ALONG WITH A SLIGHT CHANCE FOR SOME THUNDERSTORMS. THE SHOWER
ACTIVITY WILL BE MAINLY BEHIND THE COLD FRONT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
AS OF 458 AM EDT FRIDAY...THE COLD FRONT WILL MOVE THROUGH THE
REGION TONIGHT. HAVE GONE WITH LIKELY TO CATEGORICAL POPS FOR RAIN
SHOWERS TONIGHT. MUCH COOLER TEMPERATURES WILL BE OVER THE REGION
ON SATURDAY WITH HIGHS FROM THE UPPER 40S TO LOWER 50S. THERE WILL
BE A SLIGHT CHANCE FOR SOME RAIN SHOWERS OVER THE HIGHER
ELEVATIONS OF THE ADIRONDACKS AND GREEN MOUNTAINS ON SATURDAY. A
RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION SATURDAY NIGHT
AND SUNDAY...WITH LOWS SATURDAY NIGHT IN THE TEENS AND 20S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 512 AM EDT FRIDAY...SFC RIDGE NEARBY ON SUNDAY NIGHT INTO
MONDAY AND ASSOCIATED DEEP DRY LAYER WL RESULT IN MAINLY CLR
SKIES. PROGGED 85H TEMPS BTWN -2C AND -4C SUPPORT HIGHS IN THE
M40S NEK/MTNS TO M50S CPV/SLV. STILL PLENTY OF UNCERTAINTY FOR
TUESDAY AND BEYOND WITH REGARDS TO POTENTIAL COASTAL SYSTEM ON
TUESDAY AND ANOTHER GREAT LAKES CUTTER ON THURS. LATEST 00Z ECMWF
SHOWS SFC LOW PRES DEVELOPING ACRS SNE ON TUES...AS 5H S/W ENERGY
TRACKS ACRS OUR FA. ECWMF SHOWS BEST 850 TO 500MB RH JUST TOO OUR
EAST...ALONG WITH NO CLOSED 5H/7H CIRCULATION...THEREFORE FEEL
IMPACT TO OUR CWA WL BE LIMITED. WL CONT TO MENTION LOW CHC POPS.
TEMPS WL BE COOL WITH PROGGED 85H TEMPS NEAR 0C...AND LIMITED
MIXING FROM CLOUDS...THINKING MAINLY 40S EASTERN/CENTRAL VT/MTNS AND
L/M 50S ELSEWHERE. BOTH GFS/ECMWF CONTS TO SUPPORT AN ACTIVE
PATTERN WITH ANOTHER SYSTEM IMPACTING OUR FA LATE WEDS INTO THURS.
STILL SOME UNCERTAINTY WITH REGARDS TO TIMING OF MOISTURE/QPF AND
EXACT STORM TRACK. LATEST TRENDS SHOW SFC LOW PRES TRACKING TO OUR
WEST...WITH GUSTY SOUTHERLY WINDS DEVELOPING ON WEDS AFTN INTO
THURS...VERY SIMILAR TO THE SYSTEM TODAY. GIVEN EXPECTED TRACK TO
OUR WEST...ANTICIPATE OUR CWA WL BE IN THE WARM SECTOR WITH MUCH
ABOVE NORMAL TEMPS POSSIBLE WEDS INTO THURSDAY...ALONG WITH A
BRIEF 3 TO 6 HR WINDOW OF SHOWERS. WL TREND TWD ABOVE NORMAL TEMPS
AND MENTION CHC POPS ATTM. AS THE EVENT BECMG CLOSER...WL FINE
TUNE TEMPS/POP TIMING...ALONG WITH QPF AMOUNTS.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
THROUGH 12Z SATURDAY...GUSTY SOUTHERLY WINDS WL CONT TODAY AT ALL
TAF SITES...ALONG WITH A 3 TO 5 HR WINDOW OF SHOWERS AND POTENTIAL
MVFR CONDITIONS. CRNT SFC ANALYSIS SHOWS A TIGHT PRES GRADIENT
CONTS BTWN SFC LOW PRES OVER THE NORTHERN GREAT LAKES AND HIGH
PRES ACRS THE NORTH ATLANTIC. THIS WL CREATE SFC WIND GUSTS BTWN
30 AND 35 KNTS TODAY...ALONG WITH AREAS OF MODERATE LLVL
TURBULENCE. GIVEN THE LACK OF MIXING AT MPV/RUT HAVE MENTION LLVL
WS THRU 15Z. OTHERWISE...BAND OF RAIN SHOWERS WL IMPACT MSS BTWN
20-24Z TODAY...AND INTO THE CPV BY 00Z...AND EAST AND SOUTH OF
MPV/RUT BY 06Z TONIGHT. EXPECT A 3 TO 5 HR WINDOW OF MODERATE RAIN
WITH MVFR CIGS/VIS LIKELY. A WIND SHIFT TO THE WEST/SOUTHWEST IS
ANTICIPATED BY 06Z BEHIND SFC COLD FRNT. COOLER AND BREEZY
CONDITIONS WL CONT AFT 06Z...WITH MAINLY VFR CONDITIONS.
OUTLOOK 12Z SATURDAY THROUGH TUESDAY...GUSTY WINDS WL SLOWLY
DECREASE ON SATURDAY...WITH SFC HIGH PRES BUILDING INTO OUR TAF
SITES. VFR CONDITIONS WL PREVAIL THRU MONDAY...WITH SOME INCREASE
IN CLOUDS AND CHCS OF PREICP BY MONDAY NIGHT INTO
TUESDAY...ESPECIALLY MPV/RUT.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...WIND ADVISORY UNTIL 11 PM EDT THIS EVENING FOR VTZ001-002-005-
009-011.
NY...WIND ADVISORY UNTIL 11 PM EDT THIS EVENING FOR NYZ026>031-034-
035-087.
&&
$$
SYNOPSIS...WGH
NEAR TERM...JMG/WGH
SHORT TERM...WGH
LONG TERM...TABER
AVIATION...TABER
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
935 PM CDT SAT APR 20 2013
.UPDATE...
ISSUED AT 935 PM CDT SAT APR 20 2013
LIGHT SNOW BAND MOVING INTO THE NORTHWESTERN COUNTIES HAS FALLEN
APPART WITH NOT MUCH REACHING THE GROUND. NAM AND RUC HAVE BACKED
OFF ON QPF FROM THE FIRST WAVE OF WARM ADVECTION PRECIP AND NOW
HAVE MOST OF THE PRECIP COMING IN LATER ON TONIGHT/TOMORROW
MORNING WITH THE MAIN TROUGH. LOWERED POPS FOR THE REST OF THE
EVENING TO 20-30 PERCENT AND SAVED THE HIGHER POPS FOR THE EARLY
MORNING HOURS IN THE FAR NORTHWEST WHEN MAIN SYSTEM ARRIVES.
LOWERED QPF/SNOW FOR TONIGHT ALSO.
UPDATE ISSUED AT 642 PM CDT SAT APR 20 2013
ONLY A FEW MINOR TWEAKS FOR THIS UPDATE AS A BAND OF LIGHT SNOW
SLOWLY ENTERS THE FAR NORTHWESTERN CWA THIS EVENING. BAND IS
NARROW AND SHORT LIVED AND THINK THE MORE SIGNIFICANT PRECIP WILL
BE WHEN THE MAIN TROUGH AXIS/FRONTAL BOUNDARY COMES OUT TOMORROW
MORNING. BUT NOT CONFIDENT ENOUGH TO MAKE CHANGES TO POPS AFTER
MIDNIGHT SO WILL HOLD OFF UNTIL THE 00Z MODEL RUNS START COMING
IN. INCREASED CLOUDS A BIT TONIGHT AND TWEAKED TEMPS...BUT NO HUGE
CHANGES.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 322 PM CDT SAT APR 20 2013
THE FORECAST CHALLENGE FOR THE SHORT TERM FOCUSES ON A COUPLE OF
ROUNDS OF SNOWFALL MOVING IN FROM THE WEST. IN GENERAL MODELS
STRUGGLE TO AGREE ON PLACEMENT OF PRECIPITATION...BUT COMPARING
CURRENT OBS/RADAR ECHOES TO 18Z VERIFICATION...I AM LEANING TOWARD
THE GFS. OPERATIONAL MODELS SHOW LOWERING CONDENSATION PRESSURE
DEFICITS MOVING IN TO WESTERN ZONES WITH MODEST ISENTROPIC LIFT
AFT 00Z...BY 06Z INTO THE RED RIVER VALLEY...AND ACROSS THE REGION
BY 12Z. BEFORE THIS MORE WIDESPREAD CLOUD COVER/PRECIP MOVES
IN...A TIGHT BAND OF SHOWERS WILL MOVE INTO THE WEST THIS EVENING.
DO EXPECT VERY LIGHT SNOW SHOWERS WITH THE INITIAL BAND...A BRIEF
BREAK...AND THEN MORE WIDESPREAD BUT LIGHT SNOW OVERNIGHT. PREFER A
SLIGHTLY LESS SATURATED GFS COMPARED TO THE NAM...AS ECHOES OVER
MONTANA HAVE NOT BEEN THAT IMPRESSIVE. BOTH MODELS ALSO SWEEP
PRECIP THROUGH RATHER QUICKLY AS ASSOCIATED FRONT MOVES INTO RED
RIVER VALLEY AROUND 18Z SUNDAY. DO EXPECT RAPID IMPROVEMENT AIDED
BY ISENTROPIC DESCENT TOMORROW AFTERNOON.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 322 PM CDT SAT APR 20 2013
ANOTHER WAVE WILL MOVE ACROSS THE CENTRAL PLAINS ON MONDAY...WITH
THE BEST CHANCE OF ANY MEASURABLE PRECIPITATION BEING ACROSS FAR
SOUTHERN ZONES. THE TUE NIGHT THROUGH SAT TIMEFRAME WILL CONTINUE WITH
TEMPS WELL BELOW NORMAL...WITH PERIODIC CHANCES FOR LIGHT QPF.
EACH MODEL RUN CONTINUES TO DELAY THE RIDGE ALOFT INTO THE
NORTHERN PLAINS...AND WARMER AIR...SO WILL HAVE TO SLIGHTLY LOWER
INHERITED TEMPS FOR ALL PERIODS. THE BEST CHANCES FOR PRECIP
APPEARS TO BE ON WED...WITH A RAIN/SNOW MIX CHANGING TO ALL SNOW
PERHAPS BY WED NIGHT. THE NW FLOW ALOFT AND PARADE OF SHORTWAVES
WILL CONTINUE WITH THE WARMEST DAY PERHAPS ON FRI/SAT...BUT
CONFIDENCE IS LOW WITH TEMPS LIKELY NOT GETTING TOO MUCH ABOVE THE
MID 40S AT ANY POINT. THERE ARE NO MAJOR PRECIP EVENTS IN SIGHT
EITHER...SO THE SLOW MELT CYCLE SHOULD CONTINUE.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 641 PM CDT SAT APR 20 2013
NARROW BAND OF SNOW WILL MOVE INTO THE KDVL AREA IN THE NEXT FEW
HOURS AND INTO THE RED RIVER VALLEY AROUND MIDNIGHT. BRIEF VIS
REDUCTION TO 2 TO 5 SM...BUT THINK THAT MVFR CEILINGS BEHIND THE
BAND SHOULD STICK AROUND A BIT LONGER. AFTER A BREAK...MORE SNOW
WILL MOVE INTO THE REGION WITH THE MAIN FRONTAL BOUNDARY TOMORROW
MORNING. VIS AND CIGS WILL BE MOSTLY MVFR WITH SOME BRIEF DIPS TO
IFR. SOUTH WINDS AT 15 TO 20 KTS WITH HIGHER GUSTS WILL SHIFT
AROUND TO THE WEST AND THEN NORTHWEST AND REMAIN BREEZY BY
AFTERNOON. THINK THERE SHOULD BE SOME RETURN TO VFR CONDITIONS BY
LATE IN THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...SPEICHER
LONG TERM...DK/SPEICHER
AVIATION...JR
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1005 AM CDT FRI APR 19 2013
.UPDATE...
ISSUED AT 1005 AM CDT FRI APR 19 2013
MAIN FORECAST CONCERN FOR THE UPDATE THIS MORNING IS SKY COVER OR
LACK THEREOF...AND PRECIPITATION CHANCES. HIGH PRESSURE FROM
MANITOBA AND SASKATCHEWAN EXTENDS SOUTH INTO NORTH DAKOTA. THIS
HAS RESULTED IN MAINLY CLEAR SKIES WESTERN AND CENTRAL NORTH
DAKOTA...EXCEPT FOR THE FAR SOUTHWEST CORNER. A SHORTWAVE THAT
DROPPED THROUGH WESTERN NORTH DAKOTA DID PRODUCE SOME LIGHT SNOW
OVER THE SOUTHWEST. THERE ARE SOME LINGERING LIGHT SNOW SHOWERS
FROM BEACH TO BOWMAN...HOWEVER EXPECT THESE TO DISSIPATE DURING
THE MORNING. OTHERWISE...IT SHOULD REMAIN SUNNY ACROSS CENTRAL
NORTH DAKOTA TODAY...WITH INCREASING CLOUDS WEST THIS AFTERNOON.
WILL TAKE ANOTHER LOOK AT TEMPERATURES LATE MORNING OR EARLY
AFTERNOON.
UPDATE ISSUED AT 701 AM CDT FRI APR 19 2013
HIGH PRESSURE BUILDING INTO THE REGION HAS SCOURED OUT MUCH OF THE
LOW-LEVEL MOISTURE ACROSS CENTRAL NORTH DAKOTA. AS A
RESULT...DECREASED THE FIRST PERIOD SKY COVER ACROSS THE
AFOREMENTIONED REGION.
A 75+ KT 500MB JET STREAK DIVING SOUTH OVER WESTERN NORTH DAKOTA
HAS GENERATED VERY NARROW SNOW BANDS WEST THIS MORNING. AS A
RESULT...SHIFTED ISOLATED POPS A LITTLE FARTHER WEST BASED ON
CURRENT OBS/TRENDS. THIS JET STREAK SHOULD BE OVER SOUTH DAKOTA BY
MID TO LATE MORNING TAKING ANY PRECIP CHANCES WITH IT.
THE REMAINED GRIDDED WEATHER ELEMENTS ARE IN GOOD SHAPE. THE
UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT FRI APR 19 2013
THE FORECAST HIGHLIGHT FOR THE SHORT TERM PERIOD IS THE CONTINUED
CHANCES FOR LIGHT PRECIPITATION.
CURRENTLY...AN UPPER LEVEL SHORTWAVE IS DIVING SOUTHEAST OUT OF
CANADA...WHILE AN AREA OF WEAK LOW PRESSURE WAS LOCATED OVER
NORTHEASTERN MONTANA...WITH AN ASSOCIATED WARM FRONT DRAPED ACROSS
WESTERN NORTH DAKOTA AND A TRAILING COLD FRONT OVER NORTHERN
MONTANA. THE FOCUS FOR THE MID LEVEL CLOUD SHIELD AND LIGHT
PRECIPITATION THIS MORNING IS IN THE VICINITY OF THE WARM FRONT.
LATEST RADAR IMAGERY CONTINUES TO SHOW SCATTERED LIGHT RETURNS
OVER THE WEST...WHILE SURFACE OBSERVATIONS HAVE SHOWN BRIEF
PERIODS OF LIGHT SNOW. THE 00Z NAM/07Z RAP HAS THIS AREA OF LIGHT
SNOW DISSIPATING IN INTENSITY THIS MORNING...AND THUS HAVE
DECREASED POPS ACROSS THE CENTRAL PART OF THE STATE THIS MORNING.
A BRIEF LULL IN THE LIGHT PRECIPITATION WILL BE SEEN TODAY BEFORE
THE NEXT UPPER LEVEL WAVE AND ASSOCIATED SURFACE LOW PRESSURE
PROGRESSES SOUTHWARD TONIGHT. THE 00Z SUITE OF MODELS ARE IN GOOD
AGREEMENT THAT LIGHT PRECIPITATION IN THE FORM OF A LIGHT WINTRY
MIX AND LIGHT SNOW WILL MOVE INTO THE WEST BEFORE MIDNIGHT...AND
THEN SPREAD INTO THE CENTRAL AFTER MIDNIGHT.
MEANWHILE...THE CONTINUED THEME OF BELOW NORMAL TEMPERATURES WILL
CONTINUE. HIGHS WILL BE 10 TO 20 DEGREES BELOW NORMAL...AS HIGHS
WILL WARM ONLY INTO THE LOWER 30S...EXCEPT THE SOUTHWEST WHERE MID
TO UPPER 30S ARE POSSIBLE. FOR OVERNIGHT LOWS...TEMPERATURES WILL RANGE
FROM THE LOWER TEENS IN THE JAMES RIVER VALLEY TO THE UPPER 20S
FAR SOUTHWEST. A RECORD LOW TEMPERATURE FOR JAMESTOWN MAY BE IN
JEOPARDY TONIGHT...AS THE OVERNIGHT LOW IS FORECAST TO BE 12
DEGREES AND THE RECORD LOW IS 14 DEGREES SET IN 1966.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 334 AM CDT FRI APR 19 2013
THE MEDIUM RANGE MODELS CONTINUE TO PROG A WET WEEKEND FOR WESTERN
AND CENTRAL NORTH DAKOTA. A WARM FRONT PUSHING ACROSS THE REGION
WILL GENERATE CHANCE POPS SATURDAY. THE PRECIP TYPE IS EXPECTED TO
GENERALLY BE A WINTRY MIX...WITH LIGHT RAIN POSSIBLE WEST WHERE
THE WARMEST TEMPERATURES ALOFT WILL RESIDE.
AS THE WARM FRONT SHIFTS EAST SATURDAY NIGHT...A COLD FRONT WILL
ENTER WESTERN NORTH DAKOTA AFTER MIDNIGHT. THE COLD FRONT WILL
GENERATE A CHANCE OF A WINTRY MIX NORTH OF I-94 AS IT PUSHES EAST
ACROSS THE REGION SUNDAY. AREAS SOUTH OF I-94 ARE EXPECTED TO SEE
A CHANCE OF LIGHT RAIN SUNDAY. SNOW TOTALS WILL BE IN THE 1-2 INCH
RANGE NORTH...WITH MUCH LIGHTER AMOUNTS EXPECTED SOUTH AND WEST.
A DRYING/WARMING TREND IS EXPECTED MONDAY THROUGH THE END OF THE
PERIOD. HOWEVER...THE LATEST MEDIUM RANGE MODEL GUIDANCE NOW PROGS
A WEAK COLD FRONT TO PUSH THROUGH THE REGION WEDNESDAY. THIS
FEATURE IS EXPECTED TO GENERATE A SLIGHT CHANCE OF LIGHT RAIN
MIXED WITH SLEET WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 1005 AM CDT FRI APR 19 2013
HIGH PRESSURE OVER THE AREA WILL PRODUCE VFR CONDITIONS EXPECTED
AT ALL TAF SITES THROUGH 00Z SATURDAY. A SYSTEM APPROACHING FROM
THE WEST WILL BRING LOWERING CEILINGS AND A CHANCE OF
PRECIPITATION TO KISN AND KDIK BETWEEN 00-06Z SATURDAY AND KMOT
AND KBIS BETWEEN 06-12Z SATURDAY. SOUTHEAST FLOW EXPECTED AT KISN
AND KDIK. LIGHT NORTH FLOW AT KBIS...KMOT AND KJMS WILL SHIFT
SOUTHEAST THIS AFTERNOON INTO EARLY THIS EVENING.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...LTH
LONG TERM...TM
AVIATION...TWH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
701 AM CDT FRI APR 19 2013
.UPDATE...
ISSUED AT 701 AM CDT FRI APR 19 2013
HIGH PRESSURE BUILDING INTO THE REGION HAS SCOURED OUT MUCH OF THE
LOW-LEVEL MOISTURE ACROSS CENTRAL NORTH DAKOTA. AS A
RESULT...DECREASED THE FIRST PERIOD SKY COVER ACROSS THE
AFOREMENTIONED REGION.
A 75+ KT 500MB JET STREAK DIVING SOUTH OVER WESTERN NORTH DAKOTA
HAS GENERATED VERY NARROW SNOW BANDS WEST THIS MORNING. AS A
RESULT...SHIFTED ISOLATED POPS A LITTLE FARTHER WEST BASED ON
CURRENT OBS/TRENDS. THIS JET STREAK SHOULD BE OVER SOUTH DAKOTA BY
MID TO LATE MORNING TAKING ANY PRECIP CHANCES WITH IT.
THE REMAINED GRIDDED WEATHER ELEMENTS ARE IN GOOD SHAPE. THE
UPDATED GRIDDED AND TEXT PRODUCTS HAVE BEEN SENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT FRI APR 19 2013
THE FORECAST HIGHLIGHT FOR THE SHORT TERM PERIOD IS THE CONTINUED
CHANCES FOR LIGHT PRECIPITATION.
CURRENTLY...AN UPPER LEVEL SHORTWAVE IS DIVING SOUTHEAST OUT OF
CANADA...WHILE AN AREA OF WEAK LOW PRESSURE WAS LOCATED OVER
NORTHEASTERN MONTANA...WITH AN ASSOCIATED WARM FRONT DRAPED ACROSS
WESTERN NORTH DAKOTA AND A TRAILING COLD FRONT OVER NORTHERN
MONTANA. THE FOCUS FOR THE MID LEVEL CLOUD SHIELD AND LIGHT
PRECIPITATION THIS MORNING IS IN THE VICINITY OF THE WARM FRONT.
LATEST RADAR IMAGERY CONTINUES TO SHOW SCATTERED LIGHT RETURNS
OVER THE WEST...WHILE SURFACE OBSERVATIONS HAVE SHOWN BRIEF
PERIODS OF LIGHT SNOW. THE 00Z NAM/07Z RAP HAS THIS AREA OF LIGHT
SNOW DISSIPATING IN INTENSITY THIS MORNING...AND THUS HAVE
DECREASED POPS ACROSS THE CENTRAL PART OF THE STATE THIS MORNING.
A BRIEF LULL IN THE LIGHT PRECIPITATION WILL BE SEEN TODAY BEFORE
THE NEXT UPPER LEVEL WAVE AND ASSOCIATED SURFACE LOW PRESSURE
PROGRESSES SOUTHWARD TONIGHT. THE 00Z SUITE OF MODELS ARE IN GOOD
AGREEMENT THAT LIGHT PRECIPITATION IN THE FORM OF A LIGHT WINTRY
MIX AND LIGHT SNOW WILL MOVE INTO THE WEST BEFORE MIDNIGHT...AND
THEN SPREAD INTO THE CENTRAL AFTER MIDNIGHT.
MEANWHILE...THE CONTINUED THEME OF BELOW NORMAL TEMPERATURES WILL
CONTINUE. HIGHS WILL BE 10 TO 20 DEGREES BELOW NORMAL...AS HIGHS
WILL WARM ONLY INTO THE LOWER 30S...EXCEPT THE SOUTHWEST WHERE MID
TO UPPER 30S ARE POSSIBLE. FOR OVERNIGHT LOWS...TEMPERATURES WILL RANGE
FROM THE LOWER TEENS IN THE JAMES RIVER VALLEY TO THE UPPER 20S
FAR SOUTHWEST. A RECORD LOW TEMPERATURE FOR JAMESTOWN MAY BE IN
JEOPARDY TONIGHT...AS THE OVERNIGHT LOW IS FORECAST TO BE 12
DEGREES AND THE RECORD LOW IS 14 DEGREES SET IN 1966.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 334 AM CDT FRI APR 19 2013
THE MEDIUM RANGE MODELS CONTINUE TO PROG A WET WEEKEND FOR WESTERN
AND CENTRAL NORTH DAKOTA. A WARM FRONT PUSHING ACROSS THE REGION
WILL GENERATE CHANCE POPS SATURDAY. THE PRECIP TYPE IS EXPECTED TO
GENERALLY BE A WINTRY MIX...WITH LIGHT RAIN POSSIBLE WEST WHERE
THE WARMEST TEMPERATURES ALOFT WILL RESIDE.
AS THE WARM FRONT SHIFTS EAST SATURDAY NIGHT...A COLD FRONT WILL
ENTER WESTERN NORTH DAKOTA AFTER MIDNIGHT. THE COLD FRONT WILL
GENERATE A CHANCE OF A WINTRY MIX NORTH OF I-94 AS IT PUSHES EAST
ACROSS THE REGION SUNDAY. AREAS SOUTH OF I-94 ARE EXPECTED TO SEE
A CHANCE OF LIGHT RAIN SUNDAY. SNOW TOTALS WILL BE IN THE 1-2 INCH
RANGE NORTH...WITH MUCH LIGHTER AMOUNTS EXPECTED SOUTH AND WEST.
A DRYING/WARMING TREND IS EXPECTED MONDAY THROUGH THE END OF THE
PERIOD. HOWEVER...THE LATEST MEDIUM RANGE MODEL GUIDANCE NOW PROGS
A WEAK COLD FRONT TO PUSH THROUGH THE REGION WEDNESDAY. THIS
FEATURE IS EXPECTED TO GENERATE A SLIGHT CHANCE OF LIGHT RAIN
MIXED WITH SLEET WEDNESDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 701 AM CDT FRI APR 19 2013
AN AREA OF WEAK LOW PRESSURE WILL CONTINUE TO GENERATE SCATTERED
LIGHT SNOW ACROSS WESTERN NORTH DAKOTA AT KISN/KDIK. HOWEVER...THE
EASTERN EXTENT OF THE SCATTERED LIGHT SNOW IS UNCERTAIN AS MODELS
SHOW LIGHT SNOW NOT REACHING KBIS/KMOT AND THUS HAVE DECIDED TO
ELIMINATE THE MENTION OF LIGHT SNOW AT KBIS/KMOT. RESIDUAL
MOISTURE NEAR THE SURFACE COUPLED WITH COOL AIR WILL ALLOW FOR
WIDESPREAD MVFR CONDITIONS IN LIGHT FOG AND LOWERED CEILINGS ACROSS
ALL TERMINALS EXCEPT FOR KJMS...WHERE VFR CONDITIONS WILL PREVAIL.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TM
SHORT TERM...LTH
LONG TERM...TM
AVIATION...LTH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
334 AM CDT FRI APR 19 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 334 AM CDT FRI APR 19 2013
THE FORECAST HIGHLIGHT FOR THE SHORT TERM PERIOD IS THE CONTINUED
CHANCES FOR LIGHT PRECIPITATION.
CURRENTLY...AN UPPER LEVEL SHORTWAVE IS DIVING SOUTHEAST OUT OF
CANADA...WHILE AN AREA OF WEAK LOW PRESSURE WAS LOCATED OVER
NORTHEASTERN MONTANA...WITH AN ASSOCIATED WARM FRONT DRAPED ACROSS
WESTERN NORTH DAKOTA AND A TRAILING COLD FRONT OVER NORTHERN
MONTANA. THE FOCUS FOR THE MID LEVEL CLOUD SHIELD AND LIGHT
PRECIPITATION THIS MORNING IS IN THE VICINITY OF THE WARM FRONT.
LATEST RADAR IMAGERY CONTINUES TO SHOW SCATTERED LIGHT RETURNS
OVER THE WEST...WHILE SURFACE OBSERVATIONS HAVE SHOWN BRIEF
PERIODS OF LIGHT SNOW. THE 00Z NAM/07Z RAP HAS THIS AREA OF LIGHT
SNOW DISSIPATING IN INTENSITY THIS MORNING...AND THUS HAVE
DECREASED POPS ACROSS THE CENTRAL PART OF THE STATE THIS MORNING.
A BRIEF LULL IN THE LIGHT PRECIPITATION WILL BE SEEN TODAY BEFORE
THE NEXT UPPER LEVEL WAVE AND ASSOCIATED SURFACE LOW PRESSURE
PROGRESSES SOUTHWARD TONIGHT. THE 00Z SUITE OF MODELS ARE IN GOOD
AGREEMENT THAT LIGHT PRECIPITATION IN THE FORM OF A LIGHT WINTRY
MIX AND LIGHT SNOW WILL MOVE INTO THE WEST BEFORE MIDNIGHT...AND
THEN SPREAD INTO THE CENTRAL AFTER MIDNIGHT.
MEANWHILE...THE CONTINUED THEME OF BELOW NORMAL TEMPERATURES WILL
CONTINUE. HIGHS WILL BE 10 TO 20 DEGREES BELOW NORMAL...AS HIGHS
WILL WARM ONLY INTO THE LOWER 30S...EXCEPT THE SOUTHWEST WHERE MID
TO UPPER 30S ARE POSSIBLE. FOR OVERNIGHT LOWS...TEMPERATURES WILL RANGE
FROM THE LOWER TEENS IN THE JAMES RIVER VALLEY TO THE UPPER 20S
FAR SOUTHWEST. A RECORD LOW TEMPERATURE FOR JAMESTOWN MAY BE IN
JEOPARDY TONIGHT...AS THE OVERNIGHT LOW IS FORECAST TO BE 12
DEGREES AND THE RECORD LOW IS 14 DEGREES SET IN 1966.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 334 AM CDT FRI APR 19 2013
THE MEDIUM RANGE MODELS CONTINUE TO PROG A WET WEEKEND FOR WESTERN
AND CENTRAL NORTH DAKOTA. A WARM FRONT PUSHING ACROSS THE REGION
WILL GENERATE CHANCE POPS SATURDAY. THE PRECIP TYPE IS EXPECTED TO
GENERALLY BE A WINTRY MIX...WITH LIGHT RAIN POSSIBLE WEST WHERE
THE WARMEST TEMPERATURES ALOFT WILL RESIDE.
AS THE WARM FRONT SHIFTS EAST SATURDAY NIGHT...A COLD FRONT WILL
ENTER WESTERN NORTH DAKOTA AFTER MIDNIGHT. THE COLD FRONT WILL
GENERATE A CHANCE OF A WINTRY MIX NORTH OF I-94 AS IT PUSHES EAST
ACROSS THE REGION SUNDAY. AREAS SOUTH OF I-94 ARE EXPECTED TO SEE
A CHANCE OF LIGHT RAIN SUNDAY. SNOW TOTALS WILL BE IN THE 1-2 INCH
RANGE NORTH...WITH MUCH LIGHTER AMOUNTS EXPECTED SOUTH AND WEST.
A DRYING/WARMING TREND IS EXPECTED MONDAY THROUGH THE END OF THE
PERIOD. HOWEVER...THE LATEST MEDIUM RANGE MODEL GUIDANCE NOW PROGS
A WEAK COLD FRONT TO PUSH THROUGH THE REGION WEDNESDAY. THIS
FEATURE IS EXPECTED TO GENERATE A SLIGHT CHANCE OF LIGHT RAIN
MIXED WITH SLEET WEDNESDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 334 AM CDT FRI APR 19 2013
AN AREA OF WEAK LOW PRESSURE WILL CONTINUE TO GENERATE SCATTERED
LIGHT SNOW ACROSS WESTERN NORTH DAKOTA AT KISN/KDIK. HOWEVER...THE
EASTERN EXTENT OF THE SCATTERED LIGHT SNOW IS UNCERTAIN AS MODELS
SHOW LIGHT SNOW NOT REACHING KBIS/KMOT AND THUS HAVE DECIDED TO
ELIMINATE THE MENTION OF LIGHT SNOW AT KBIS/KMOT. RESIDUAL
MOISTURE NEAR THE SURFACE COUPLED WITH COOL AIR WILL ALLOW FOR
WIDESPREAD MVFR CONDITIONS IN LIGHT FOG AND LOWERED CEILINGS ACROSS
ALL TERMINALS EXCEPT FOR KJMS...WHERE VFR CONDITIONS WILL PREVAIL.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LTH
LONG TERM...TM
AVIATION...LTH
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1143 PM CDT THU APR 18 2013
.UPDATE...
ISSUED AT 1140 PM CDT THU APR 18 2013
NO CHANGES PLANNED FOR THIS UPDATE PERIOD. -SN CONTINUES ACROSS
THE FAR SE SO WILL MAINTAIN POPS THIS AREA. TEMPERATURES ON TRACK.
UPDATE ISSUED AT 940 PM CDT THU APR 18 2013
ONLY MINOR CHANGES FOR THIS UPDATE. -SN CONTINUES TO SHIFT EAST
WITH VERY FAR SE ONLY STATIONS REPORTING LIGHT SNOW. TRIMMED POPS
SOMEWHAT ACROSS THE FAR EAST BASED ON CURRENT RADAR TRENDS AND
SURFACE REPORTS. TEMPERATURES DROPPING ABOUT AS EXPECTED. MIXING
AND SOME ADVANCING CLOUD COVER ACROSS WESTERN DAKOTAS SHOULD LIMIT
DROP KEEPING MINIMUM TEMPERATURES PRETTY CLOSE TO WHAT WE HAVE
SEEN LAST COUPLE OF NIGHTS. NO CHANGES PLANNED AT THIS POINT.
UPDATE ISSUED AT 640 PM CDT THU APR 18 2013
PRIMARY CHANGES THIS UPDATE WILL BE TO CANCEL/EXPIRE CURRENT
ADVISORY ACROSS FAR SE FA. SNOW CONTINUES ACROSS THE FAR SE
HOWEVER WITH MINIMAL ACCUMULATIONS TODAY WITH TEMPERATURES ABOVE
FREEZING ALONG WITH IMPROVING VSBY FEEL THREAT FOR ACCUMULATING
SNOW OVER. CURRENT POPS LOOKING GOOD FOR REMAINDER OF THE EVENING
AS SYSTEM SLOWLY PUSHES EAST. NO CHANGES PLANNED TO TEMPERATURES
AT THIS POINT.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 320 PM CDT THU APR 18 2013
THE PRIMARY CHALLENGE FOR THE IMMEDIATE SHORT TERM WILL BE TIMING
THE DISSIPATION OF THE SNOWFALL IN THE SOUTHEAST (WEST CENTRAL
MINNESOTA). RADAR CONTINUES TO SHOW WEAK ECHOES ROUGHLY SOUTH OF A
BAGLEY TO DETROIT LAKES TO WAHPETON LINE...WITH SOME LINGERING
LIGHT SNOW IN FAR SOUTHEASTERN RICHLAND COUNTY. HAVE USED RUC
GUIDANCE FOR QPF AND SNOWFALL CALCULATIONS IN THE REGION.
THIS EVENING...A JET STREAK THAT HAS HELPED AMPLIFY SNOWFALL OVER
SOUTHERN AND WEST CENTRAL MINNESOTA WILL MOVE OUT OF THE REGION
AND FORCING WILL WEAKEN. ISENTROPIC MODELS SHOW RISING
CONDENSATION PRESSURE DEFICITS AND NO ISENTROPIC LIFT FOR
REMAINDER OF AFTERNOON INTO THE EVENING. WHILE BOTH THE GFS AND
NAM SHOW UNSATURATED DEFICITS BY AROUND 00Z...MODELS CONTINUE TO
PRODUCE QPF THROUGH AROUND 06Z. FOR BLENDING PURPOSES WILL KEEP
LOWER POPS IN THE EXTREME SOUTHEAST THROUGH 12Z FRIDAY...BUT THINK
MOST PRECIP WILL BE OUT OF THE REGION BY MIDNIGHT.
RUC QPF VALUES SHOW A VERY TIGHT QPF GRADIENT RIGHT ALONG THE
BORDERS OF THE MINNEAPOLIS AND DULUTH COUNTY WARNING AREAS (ALONG
AND SOUTH OF A PARK RAPIDS TO PELICAN RAPIDS LINE)...WITH US ON THE
DRIER SIDE. LATEST RUC DID SURGE THE MOISTURE A BIT FURTHER
NORTH...SO WILL CONTINUE AN ADVISORY BUT IT WILL LIKELY BE IN THE
TWO TO FOUR INCH RANGE AT MOST. RECENT CALL TO GRANT COUNTY
SHERIFF INDICATES SNOW HAS PERSISTED ALL DAY BUT HAS MELTED AS IT
HIT PAVED SURFACES AND LESS THAN A HALF AN INCH ACCUMULATION ON
GRASS COVERED SURFACES. THUS PLAN TO KEEP HEADLINES AS THEY ARE...WITH A
00Z EXPIATING TIME.
WILL SEE A BRIEF PERIOD OF CLEAR SKIES IN EASTERN NORTH DAKOTA
TONIGHT...WHICH ALLOW TEMPS TO DROP INTO THE TEENS. HOWEVER MID
CLOUD WILL MOVE IN FROM SASK BY MORNING.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 320 PM CDT THU APR 18 2013
THE NEXT WINTER SYSTEM WILL MOVE INTO THE REGION ON SATURDAY
AFTERNOON. A BAND OF MODERATE ISENTROPIC LIFT WILL MOVE ACROSS THE
REGION LATE SAT AND TRANSLATE ACROSS THE FORECAST AREA ON SUNDAY.
MODELS INDICATING SIGNIFICANT DIFFERENCES ON ORIENTATION OF PRECIP
AND THERMAL PROFILES...WITH THE NAM SHOWING A MUCH MORE PRONOUNCED
WARM LAYER BY ENOUGH OF A LOW LEVEL COLD LAYER FOR SOME REFREEZING
TO OCCUR. GFS IS COLDER AND SHOWS MOST PRECIP ACROSS THE SOUTH. DO
PREFER THE GFS SOLUTION AND HAVE HIGHEST POPS ACROSS SOUTHERN
ZONES. WILL GO WITH SNOW WITH SOME POSSIBLE SLEET/ICE PELLETS SAT
NIGHT AND SUN MORNING...WITH A BETTER CHANCE FOR RAIN SUN AFTN.
WILL NEED TO MONITOR UPCOMING MODELED THERMAL PROFILES TO FINE
TUNE THIS FCST PERIOD.
MODELS ARE IN DECENT AGREEMENT DEPICTING NORTHWEST FLOW ALOFT. THE
MODELS AGAIN DELAY THE UPPER RIDGE AND MUCH WARMER AIRMASS. THERE
WILL BE MINOR PRECIP CHANCES WITH THE HARD TO TIME
SHORTWAVES...BUT NOTHING MAJOR. THE CHALLENGING ASPECT WILL BE
WHEN/IF THE SNOWPACK ERODES ENOUGH THAT WE CAN START TRUSTING MOS
GUIDANCE (WHICH ASSUMES NO SNOW COVER). MIN TEMPS EARLY NEXT WEEK
ARE EXPECTED TO BE AROUND 30F...THUS REMAINING ABOVE FREEZING FOR
A LONGER DURATION DURING THE OVERNIGHT HOURS. THIS MAY BE ENOUGH
FOR AREAS WITHIN THE VALLEY TO LOSE ENOUGH SNOW COVER BY THE
MIDDLE OF NEXT WEEK ALLOWING SLIGHTLY WARMER MAX TEMPS (WITH THE
DEVILS LAKE BASIN REMAINING SNOW COVERED). THE AIRMASS WILL
UNDERGO LITTLE CHANGE THROUGH NEXT WEEK FROM WHAT IT IS NOW...AND
WHERE THERE IS SNOW COVER EXPECT MAX TEMPS INTO THE UPPER 30S OR
LOW 40S...WITH MID TO UPPER 40S WHERE SOME BLACK FIELDS START
APPEARING. NOT SURE ABOUT THE FORESTED AREAS IN MINNESOTA...AND WE
MAY BE TOO COLD FOR THIS AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1140 PM CDT THU APR 18 2013
ALL TAF SITES VFR AND ANTICIPATED TO REMAIN SO OVERNIGHT.
CONVECTIVE TEMPERATURES LOWER TOMORROW SO COULD SEE SOME VFR CIGS
DEVELOPING ACROSS THE REGION BY LATE AM.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...SPEICHER
LONG TERM...TG/SPEICHER
AVIATION...VOELKER
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1118 PM MDT THU APR 18 2013
.UPDATE...
ISSUED AT 852 PM MDT THU APR 18 2013
02Z SURFACE ANALYSIS HAD LOW OVER SOUTH CENTRAL SK WITH COLD FRONT
INTO SOUTHERN AB. WATER VAPOUR HAD COMPACT SHORTWAVE OVER SOUTH
CENTRAL SK...ON NOSE OF 90KT JET STREAK. 00Z RAP SHOWED DECENT
POTENTIAL VORTICITY MAXIMUM ASSOCIATED WITH THIS WAVE...WHICH WILL
RACE SOUTHEAST OVERNIGHT DRAGGING COLD FRONT WITH IT ALONG WITH A
NARROW BAND OF LIFT ASSOCIATED WITH 850-700MB FRONTOGENESIS AND
SYNOPTIC SCALE LIFT UNDER JET STREAK. 00Z KUNR SOUNDING PRETTY
DRY...SO A LOT OF LIFT WILL BE WASTED ON SATURATION. GIVEN
UPSTREAM RADAR RETURNS ASSOCIATED WITH WAVE WILL INTRODUCE
ISOLATED POPS THROUGH EARLY FRIDAY MORNING TO ACCOUNT. HAVE ALSO
UPPED WINDS GIVEN NARROW SHOT OF COLD AIR ADVECTION BEHIND COLD
FRONT AND 30KT 850MB WIND MAX...COULD BE A FEW BREEZY/WINDY SPOTS
TOWARD MORNING.
&&
.SHORT TERM...THIS EVENING THROUGH FRIDAY NIGHT
ISSUED AT 221 PM MDT THU APR 18 2013
CURRENT SURFACE ANALYSIS PLACES LOW OVER THE MIDWEST WITH HIGH
OVER THE NRN ROCKIES. UPPER LEVEL ANALYSIS PLACES DEEP TROF AXIS
PUSHING OVER THE RED RIVER VALLEY WITH CLOSED OFF LOW WORKING ITS
WAY FROM SERN SD/NWRN NEB INTO ERN IA. BREEZY CONDITIONS CONTINUE
OVER THE SODAK PLAINS IN MODEST PRESSURE GRADIENT...WITH POSSIBLY
A FEW SNOW SHOWERS OVER THE ERN CWA IN CYCLONIC FLOW IN THE WAKE
OF DEPARTING SYSTEM.
FOR TONIGHT...QUIET WEATHER IS EXPECTED AS LOW/TROF CONTINUE TO
PUSH OFF TO THE EAST WITH ANY LINGERING SHOWERS ENDING. TEMPS WILL
BE QUITE CHILLY IN THE WAKE OF DEPARTING SYSTEM.
ON FRIDAY...RIDGE TRIES TO WORKS ITS WAY INTO THE AREA WITH TEMPS
REBOUNDING. A VARIETY OF WEAK SHORT WAVES SLIDE THROUGH THE RIDGE
AND APPROACH THE AREA LATE DAY INTO THE EVENING BRINGING CHANCES
FOR RAIN OR SNOW SHOWERS.
&&
.LONG TERM...SATURDAY THROUGH THURSDAY
ISSUED AT 221 PM MDT THU APR 18 2013
WEAK UPPER LEVEL RIDGE WILL SLIDE ACROSS THE NORTHERN PLAINS ON
SATURDAY...WITH SURFACE WARM FRONT PUSHING INTO THE EASTERN DAKOTAS.
LOW LEVEL THERMAL RIDGE IN PLACE WOULD NORMALLY PUT HIGH
TEMPERATURES INTO THE 50S/60S. HOWEVER...LINGERING SNOW COVER/MOIST
GROUND FROM MELTING WILL HOLD TEMPERATURES BACK SOME. AN UPPER LEVEL
TROF WILL THEN SET UP ACROSS THE NORTHERN PLAINS SUNDAY INTO EARLY
NEXT WEEK. BEST CHANCE OF PRECIPITATION WILL COME SUNDAY
NIGHT/MONDAY WITH ANOTHER CHANCE OF ACCUMULATING SNOW. BELOW AVERAGE
TEMPERATURES EXPECTED FOR THE FIRST HALF OF THE WEEK.
NORTH-NORTHWEST FLOW WILL PERSIST THROUGH MID WEEK WITH A SLOW
WARMING TREND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1115 PM MDT THU APR 18 2013
A FAST MOVING COLD FRONT WILL BRING A PERIOD OF GUSTY NORTHWEST
WINDS ACROSS NORTHWEST SD LATE TONIGHT/EARLY FRIDAY MORNING...SOME
LOCAL MVFR CIGS MAY OCCUR NEAR THE HIGHER TERRAIN AND NEAR
ISOLATED -SHSN. OTHERWISE...VFR CONDITIONS WILL PREVAIL WITH CIGS
FROM ABOUT 4-8KFT WITH A FEW SHOWERS FRIDAY AFTERNOON/EVENING.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&
$$
UPDATE...HELGESON
SHORT TERM...77
LONG TERM...7
AVIATION...HELGESON
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
912 PM CDT SAT APR 20 2013
.UPDATE...
ISSUED AT 912 PM CDT SAT APR 20 2013
THE MAIN FOCUS THROUGH THE NIGHT IS ON A BAND OF SNOW CURRENTLY IN
SOUTHWEST MINNESOTA THAT IS DEVELOPING AHEAD/ALONG SOME STRONG
850MB WARM AIR ADVECTION AND ISENTROPIC LIFT ON THE 290K SURFACE.
AS THIS FORCING SHIFTS EAST TONIGHT...IT WILL ENCOUNTER DRY
SURFACE/LOW LEVEL AIR THAT IS IN PLACE DUE TO THE RIDGE OF HIGH
PRESSURE THAT IS CURRENTLY ALIGNED ALONG THE MISSISSIPPI RIVER.
MANY OF THE EARLY RETURNS SHOWING UP ON RADAR IN SOUTH CENTRAL
MINNESOTA ARE JUST VIRGA WITH A 20F SURFACE DEW POINT DEPRESSION
TO OVERCOME. AS THE FORCING STRENGTHENS AND THE SNOW CONTINUES TO
FALL THROUGH THE DRY LAYER...IT WILL EVENTUALLY MAKE IT DOWN TO
THE GROUND OVERNIGHT. 21.00Z RAP SOUNDINGS SHOW THAT THE MAIN
WARM LAYER TO BE CONCERNED WITH IS THE SURFACE LAYER AND HOW MUCH
THAT COOL DOWN TO THE WET BULB TEMPERATURE AS THE SNOW BEGINS.
THROUGH 12Z...IT APPEARS THAT TEMPERATURES SHOULD BE COLD ENOUGH
THAT ANY PRECIPITATION FALLING SHOULD REACH THE GROUND AS SNOW.
HOW MUCH ACCUMULATION FALLS IS THE NEXT QUESTION AS SOME OF THE
SNOWFALL RATES COULD BE QUITE HIGH THOUGH VERY BRIEF. WITH
SURFACE/GROUND TEMPERATURES NEAR OR SLIGHTLY ABOVE
FREEZING...EXPECT THAT THERE WOULD BE SOME INITIAL MELTING BEFORE
THE SNOW WOULD START ACCUMULATING...THOUGH THE SNOW RATES SHOULD
OVERCOME THAT QUICKLY. DUE TO THE SNOW LIKELY ONLY FALLING FOR A
FEW HOURS OR LESS...THINK THAT ACCUMULATIONS SHOULD STAY AT LESS
THAN AN INCH WITH THE HIGHER CHANCES FOR SAID ACCUMULATIONS
OCCURRING IN SOUTHEAST MINNESOTA/WESTERN WISCONSIN.
AFTER THE LEAD WEST TO EAST BAND OF WARM AIR ADVECTION SNOW MOVES
THROUGH...THERE COULD BE SOME MORE SHOWERY TYPE OF A RAIN/SNOW MIX
AS THE 850MB WARM LAYER MOVES IN AROUND/AFTER 12Z...THOUGH THE
21.00Z RAP SOUNDINGS SHOW SOME RAPID DRYING OUT OF THE LOW LEVELS
AS THE WARM LAYER COMES IN. MAINLY EXPECT THE PRECIPITATION TO
FALL AS SNOW THROUGH MUCH OF THE REGION THROUGH TOMORROW MORNING
BEFORE A BREAK COMES IN THE FORM OF THE WARM SECTOR. MORE SHOWERS
MOVE IN WITH THE COLD FRONT WITH A FEW THUNDERSTORMS POSSIBLE AS
WELL AHEAD OF THE COLD FRONT. SEVERE POTENTIAL LOOKS MINIMAL WITH
THE STRONGEST SHEAR LAGGING BEHIND THE INSTABILITY/FROPA.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 321 PM CDT SAT APR 20 2013
WEAK SHORT WAVE TROUGH OVER THE WESTERN DAKOTAS WILL CONTINUE TO
MOVE SLOWLY EAST TOWARD THE AREA TONIGHT AND THEN LIFT NORTHEAST
PAST THE REGION SUNDAY AHEAD OF AN APPROACHING LONG WAVE TROUGH IN
THE NORTHERN STREAM. THE WAVE DOES NOT HAVE MUCH OF A CHANCE TO
AMPLIFY AND THIS IS REFLECTED IN THE MODELS ONLY SHOWING ABOUT 4
PVU/S OF VORTICITY ADVECTION IN THE 500-300 MB LAYER.
HOWEVER...THERE SHOULD BE A GOOD LOW LEVEL THERMODYNAMIC RESPONSE
LATE TONIGHT INTO SUNDAY MORNING. HIGH PRESSURE CURRENTLY
EXTENDING FROM MINNESOTA INTO ILLINOIS WILL MOVE OFF INTO THE
EASTERN GREAT LAKES AS A COLD FRONT PUSHES INTO THE DAKOTAS WITH
THE MAIN LONG WAVE TROUGH. WARM AIR ADVECTION BETWEEN THESE TWO
SYSTEMS WILL DEVELOP LATE TONIGHT WITH A NICE ISENTROPIC UP GLIDE
SIGNAL DEVELOPING. BOTH THE 20.12Z NAM AND GFS SHOW BETWEEN 4 AND
7 UBAR/S OF UP GLIDE ON THE 295K SURFACE MOVING NORTHEAST ACROSS
THE AREA WITH THIS WARM AIR ADVECTION. BOTH MODELS ALSO SHOW A
NICE MOISTURE TRANSPORT SIGNAL DEVELOPING WITH THE NOSE OF THIS
POINTED RIGHT INTO THE ISENTROPIC UP GLIDE. EXPECTING THAT THIS
FORCING WILL BE ENOUGH TO CAUSE PRECIPITATION TO DEVELOP AFTER
MIDNIGHT AND THEN EXPAND ACROSS MUCH OF THE AREA FOR SUNDAY
MORNING. SOME CONCERN FOR THE PRECIPITATION TYPE AS TEMPERATURES
WILL INITIALLY BE COLD ENOUGH FOR SNOW BUT THESE WILL BEGIN TO
SLOWLY RISE LATE TONIGHT AND CONTINUE INTO SUNDAY MORNING CHANGING
THE SNOW OVER TO RAIN. THE WARM LAYER LOOKS TO BE PRIMARILY
CONFINED TO NEAR THE SURFACE SO NOT EXPECTING ANY FREEZING RAIN
OR SLEET TO OCCUR...BUT IF THE PRECIPITATION WOULD ARRIVE BEFORE
THERE IS ICE IN THE CLOUDS...SOME FREEZING RAIN NOT TOTALLY OUT OF
THE QUESTION IN THE I94 CORRIDOR. AS THIS AREA OF PRECIPITATION
LIFTS NORTHEAST SUNDAY AFTERNOON...EXPECTING A GENERAL DECREASE IN
THE CHANCES FOR THE REMAINDER OF THE AREA UNTIL THE COLD FRONT
BEGINS TO APPROACH THE WESTERN SECTIONS LATE SUNDAY AFTERNOON.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 321 PM CDT SAT APR 20 2013
THE INCOMING LONG WAVE TROUGH IS EXPECTED TO TAKE ON A POSITIVE
TILT AS IT BECOMES VERY SLOW MOVING. THE INITIAL SHORT WAVE TROUGH
AND UPPER LEVEL LOW WILL MOVE NORTHEAST TOWARD HUDSON BAY AS
ADDITIONAL WAVES DROP INTO THE WESTERN PART OF THE LONG WAVE
TROUGH. THESE WAVES ARE THEN EXPECTED TO MOVE NORTHEAST ACROSS THE
UPPER MIDWEST MONDAY THROUGH TUESDAY. THE COLD FRONT WILL MOVE
INTO THE REGION SUNDAY AND THEN BECOME NEARLY STATIONARY OVER THE
AREA THROUGH MONDAY AS THE WAVES MOVE NORTHEAST ALONG IT. A BAND
OF WEAK TO MODERATE FRONTOGENESIS IS EXPECTED TO SET UP ALONG THE
FRONT IN THE 1000 TO 500 MB LAYER AND THERE SHOULD ALSO BE
PERSISTENT UP GLIDE OF 2 TO 3 UBAR/S ON THE 290K SURFACE. SOME JET
DYNAMICS SHOULD ALSO COME INTO PLAY SUNDAY NIGHT AND MONDAY AND
THIS COULD BECOME COUPLED BETWEEN WITH RIGHT ENTRANCE REGION OF
A JET CORE ALONG THE CANADIAN BORDER AND THE LEFT EXIT REGION OF A
SECOND JET CORE CROSSING THE ROCKIES INTO THE CENTRAL PLAINS.
WITH ALL THIS FORCING...EXPECTING AN EXTENDED PERIOD OF
PRECIPITATION FROM SUNDAY NIGHT INTO MONDAY NIGHT. ENOUGH MODEL
DIFFERENCES YET ON WHERE THE FRONT WILL SET UP TO PRECLUDE GOING
ANY HIGHER THAN 70 PERCENT ON THE PRECIPITATION CHANCES AT THIS
POINT. HOWEVER...WILL NEED TO RAISE THESE CHANCES WITH LATER
FORECASTS AS IT SEEMS A GIVEN THAT THERE WILL BE PRECIPITATION
AROUND. MOST OF THIS PRECIPITATION IS EXPECTED TO FALL AS RAIN
UNTIL ENOUGH COLD AIR STARTS TO GET DRAWN IN BEHIND THE FRONT TO
ALLOW FOR A CHANGE OVER TO SNOW TO BEGIN LATE MONDAY NIGHT. THE
POTENTIAL EXISTS THAT AREAS NORTH OF HIGHWAY 10 COULD GET 1 TO 3
INCHES OF SNOW MONDAY NIGHT.
WILL CONTINUE TO CARRY SOME LOW END PRECIPITATION CHANCES ACROSS
THE EASTERN SECTIONS TUESDAY AND TUESDAY NIGHT AS THE 20.12Z ECMWF
IS SLOWER TO MOVE THE FRONT INTO THE OHIO RIVER VALLEY AS IT
BRINGS YET ANOTHER WAVE UP ALONG THE FRONT. ONLY A VERY SHORT
BREAK IN THE PRECIPITATION CHANCES IS EXPECTED BEFORE THE NEXT
SYSTEM DROPS IN FROM THE NORTHWEST FOR WEDNESDAY NIGHT AND
THURSDAY. TEMPERATURES STILL LOOK TO BE COLD ENOUGH FOR THIS
SYSTEM TO PRODUCE SOME LIGHT SNOW FOR MUCH OF THE AREA. WITH THE
FLOW REMAINING NORTHWEST ALOFT...YET ANOTHER FAST MOVING SYSTEM
SHOULD COME IN FOR THE END OF THE WEEK FOR THE POSSIBILITY OF
ANOTHER ROUND OF PRECIPITATION FOR FRIDAY AND SATURDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 639 PM CDT SAT APR 20 2013
CLEAR SKIES WILL GIVE WAY TO INCREASING MID TO HIGH LEVEL CLOUD
COVER THIS EVENING AS THE NEXT SYSTEM APPROACHES THE REGION FROM
THE WEST. A BAND OF SNOW CURRENTLY NEAR SIOUX FALLS SOUTH DAKOTA
WILL TRACK TO THE EAST-NORTHEAST TONIGHT. THIS BAND APPEARS SET TO
GET INTO RST AROUND 7Z AND LSE AROUND 9Z IF THE DRY LOW LEVEL AIR
DOES NOT WIN OUT. SOME MODEL GUIDANCE SUGGESTS THAT THIS MAIN BAND
MAY LIFT TO THE NORTH OF THE SITES...BUT MOST OF THE MODELS ARE
SHOWING IT COMING IN. PRECIPITATION TYPE WILL START AS SNOW BUT
THEN TRANSITION TO A RAIN...SNOW MIX BEFORE BECOMING ALL RAIN
BEFORE IT ENDS BY MID MORNING. FLIGHT CONDITIONS ARE EXPECTED TO
DROP TO THE MVFR/IFR RANGE AS THIS BAND MOVES THROUGH BEFORE
IMPROVING IN THE MID TO LATE MORNING HOURS AS WINDS COME AROUND TO
THE SOUTH. AFTER THIS BREAK...ANOTHER ROUND OF RAIN SHOWERS WILL
MOVE IN FROM THE WEST IN THE LATE AFTERNOON WITH A FEW
THUNDERSTORMS POSSIBLE AS WELL. LSE PROBABLY WILL NOT SEE THIS
NEXT ROUND OF SHOWERS UNTIL THE EVENING HOURS HOWEVER.
&&
.HYDROLOGY...
ISSUED AT 321 PM CDT SAT APR 20 2013
AT THIS POINT...THE PRECIPITATION AMOUNTS EXPECTED FROM TONIGHT
THROUGH TUESDAY SHOULD RANGE FROM 0.5 TO 1.25 INCHES. THIS SHOULD
COME OVER A LONG ENOUGH PERIOD TO NOT CAUSE ANY ADDITIONAL
FLOODING...BUT SOME WITHIN BANKS WILL MOST LIKELY OCCUR. IT MAY
BECOME NECESSARY TO ISSUE FLOOD WATCHES IF IT LOOKS LIKE THERE
WILL BE MORE PRECIPITATION THAN THIS. OTHERWISE...THE ONGOING
FLOODING ALONG THE BLACK AND TREMPEALEAU RIVERS WILL CONTINUE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
UPDATE...HALBACH
SHORT TERM...04
LONG TERM...04
AVIATION...HALBACH
HYDROLOGY...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1206 PM CDT FRI APR 19 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 255 PM CDT THU APR 18 2013
LATEST WATER VAPOR SATELLITE IMAGERY PLACED A SHORTWAVE TROUGH OVER
THE REGION...WITH TRENDS DRIVING IT EAST/NORTHEAST. GOOD MID LEVEL
DRY PUNCH ALSO INDICATED...WHICH SHOWS UP IN THE RAP BUFKIT
SOUNDINGS. THIS HAS RESULTED IN THE LOSS OF ICE IN SOME OF THE
CLOUD...AND MOSTLY AREAS OF DRIZZLE AHEAD OF TROUGH/UPPER LEVEL LOW.
DEPENDING ON SFC TEMPS...THERE COULD BE SOME PATCHY FREEZING
DRIZZLE. WEST-EAST RUNNING X-SECTION AND BUFKIT SOUNDINGS DO POINT
TO A RETURN OF THE ICE QUICKLY EARLY THIS MORNING...AND THUS EITHER
SNOW OR RAIN. GIVEN THE MOVEMENT OF THE SYSTEM...THE BETTER CHANCES
FOR ACCUMULATING PCPN WILL BE ACROSS THE NORTH...AND MOSTLY THIS
MORNING.
FOR THE AFTERNOON...RAP SOUNDINGS BUILD SOME SHALLOW NEAR SFC
INSTABILITY...UP TO AROUND 800 MB. 1000-850 MB LAPSE RATES ARE
AROUND 8.5 C/KM. ENOUGH LOW LEVEL SATURATION THAT THIS INSTABILITY
SHOULD RESULT IN SCT/WIDESPREAD SHOWERS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 255 AM CDT FRI APR 19 2013
RELATIVELY STRONG 925-850 MB WARM AIR ADVECTION AND ISENTROPIC
UPGLIDE ON THE 280-290 K SFCS SLATED TO MOVE ACROSS THE FORECAST
AREA BETWEEN 06Z SUN - 00Z MON. THE LOW LEVEL THERMODYNAMIC FORCING
IS AHEAD OF A SHORTWAVE TROUGH SLATED TO DROP SOUTHEAST OVER THE
NORTHERN PLAINS SUN AFTERNOON...AND BE A PLAYER IN PCPN CHANCES FOR
THE REGION FOR THE EARLY PART OF THE NEW WORK WEEK. A FEW PIECES OF
UPPER LEVEL ENERGY AHEAD OF THE TROUGH...WHICH WOULD ADD TO THE
FORCING MIX FOR SUN. WEST-EAST RUNNING X-SECTION POINTS TO
INCREASING SATURATION BY 06Z SUN...DEEP ENOUGH AND COLD ENOUGH FOR
THERE TO BE ICE IN THE CLOUD. PRETTY GOOD CHANCE FOR SOME PCPN WITH
THE LOW LEVEL FORCING...WITH A SNOW/RAIN MIX INITIALLY CHANGING OVER
TO RAIN DURING THE DAY SUNDAY. A HINT OF INSTABILITY IN NAM BUFKIT
SOUNDINGS...BUT NOT MUCH/IF ANY IN THE GFS. WILL KEEP THUNDER
MENTION OUT OF THE FORECAST FOR NOW.
THE TROUGH/S SFC LOW/COLD FRONT SWING IN SUN NIGHT. GFS AND NAM AT
ODDS WITH THE TIMING...WITH THE 19.00Z NAM BRINGING THE FRONT TO THE
MISSISSIPPI RIVER AROUND 03Z MON...WITH THE GFS HOLDING OFF UNTIL
CLOSER TO 12Z MON. THE EC AND GEM ARE CLOSER TO THE GFS. WILL LIKELY
LEAN THIS WAY FOR TIMING. WITH SOME LOW LEVEL MOISTURE RETURN AHEAD
OF THE FRONT...IT WILL SERVE AS ANOTHER FOCUS FOR PCPN GENERATION.
THE GFS AND EC SWING BITS OF UPPER LEVEL ENERGY ACROSS THE REGION
SUN NIGHT-TUE NIGHT...AHEAD OF AN UPPER LEVEL TROUGH WHICH MOVES
OVER THE UPPER MISSISSIPPI RIVER VALLEY TUE NIGHT. THE UPPER LEVEL
FORCING WILL INTERACT WITH A SLOW MOVING NORTH-SOUTH RUNNING FRONTAL
BOUNDARY TO PRODUCE AREAS OF PCPN. MOST WOULD FALL AS RAIN...BUT
SOME MIX WITH AND THEN CHANGE OVER TO SNOW AS THE TROUGH EXITS LATE
TUE NIGHT IS LIKELY.
A BRIEF BREAK ON WED AS HIGH PRESSURE BUILDS IN...BUT IT JUST AS
QUICKLY EXITS SOUTHEAST ALLOWING FOR ANOTHER UPPER LEVEL SHORTWAVE
TROUGH TO DROP IN FROM THE NORTHWEST. GFS/EC BOTH IN AGREEMENT WITH
SPINNING THIS FEATURE ACROSS THE REGION WED NIGHT-THU...WITH MORE
LIGHT PCPN CHANCES RESULTING. MOSTLY RAIN...BUT THERE WOULD BE SOME
SNOW CHANCES TOO.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1206 PM CDT FRI APR 19 2013
CYCLONIC FLOW AROUND THE SURFACE LOW OVER LAKE SUPERIOR CONTINUES
TO GENERATE WIDESPREAD CLOUDS AND SOME SNOW SHOWERS ACROSS THE
AREA. EXPECT THIS TREND TO CONTINUE FOR THE REMAINDER OF THE
AFTERNOON INTO THE EVENING. THE CYCLONIC FLOW AND LOW LEVEL
INSTABILITY SHOULD WEAKEN ENOUGH BY MID EVENING TO ALLOW THE
SHOWERS TO DISSIPATE WITH THE WINDS DIMINISHING AS WELL. UNTIL
THIS HAPPENS...CEILINGS AND VISIBILITY EXPECTED TO PRIMARILY BE
VFR ALTHOUGH THERE WILL BE SOME SHORT PERIODS WHEN A SNOW SHOWER
COULD REDUCE THE VISIBILITY AND CEILINGS TO MVFR. BACK EDGE OF THE
CLOUDS ACROSS NORTHWEST MINNESOTA HAS BEEN MOVING STEADILY
SOUTHEAST AND EXTRAPOLATION OF THIS TIMING WOULD BRING THE
CLEARING INTO KRST AROUND 04Z OR SO AND KLSE AROUND 07Z. THIS
TREND WAS ALREADY IN THE PREVIOUS FORECAST BUT JUST MOVED THE
TIMING UP AT KRST A LITTLE BIT. SKIES SHOULD THEN GO CLEAR
OVERNIGHT WITH SOME DIURNAL CUMULUS EXPECTED TO FORM LATE SATURDAY
MORNING. NOT ENOUGH OF A CHANGE IN THE FORECAST TO INCLUDE THESE
TRENDS AT THIS TIME.
&&
.HYDROLOGY...
ISSUED AT 255 AM CDT FRI APR 19 2013
FLOODING IS CURRENTLY OCCURRING ALONG PORTIONS OF THE BLACK AND
TREMPEALEAU RIVERS. RECENT RAINFALL WILL KEEP THOSE RIVERS ABOVE
FLOOD STAGE INTO THE EARLY WEEKEND.
WET CONDITIONS WILL PERSIST INTO THE EARLY PART OF THE NEW WORK
WEEK...BUT SIGNIFICANT ACCUMULATIONS ARE NOT EXPECTED THROUGH AT
LEAST MONDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...04
HYDROLOGY....BOYNE/RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
644 AM CDT FRI APR 19 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 255 PM CDT THU APR 18 2013
LATEST WATER VAPOR SATELLITE IMAGERY PLACED A SHORTWAVE TROUGH OVER
THE REGION...WITH TRENDS DRIVING IT EAST/NORTHEAST. GOOD MID LEVEL
DRY PUNCH ALSO INDICATED...WHICH SHOWS UP IN THE RAP BUFKIT
SOUNDINGS. THIS HAS RESULTED IN THE LOSS OF ICE IN SOME OF THE
CLOUD...AND MOSTLY AREAS OF DRIZZLE AHEAD OF TROUGH/UPPER LEVEL LOW.
DEPENDING ON SFC TEMPS...THERE COULD BE SOME PATCHY FREEZING
DRIZZLE. WEST-EAST RUNNING X-SECTION AND BUFKIT SOUNDINGS DO POINT
TO A RETURN OF THE ICE QUICKLY EARLY THIS MORNING...AND THUS EITHER
SNOW OR RAIN. GIVEN THE MOVEMENT OF THE SYSTEM...THE BETTER CHANCES
FOR ACCUMULATING PCPN WILL BE ACROSS THE NORTH...AND MOSTLY THIS
MORNING.
FOR THE AFTERNOON...RAP SOUNDINGS BUILD SOME SHALLOW NEAR SFC
INSTABILITY...UP TO AROUND 800 MB. 1000-850 MB LAPSE RATES ARE
AROUND 8.5 C/KM. ENOUGH LOW LEVEL SATURATION THAT THIS INSTABILITY
SHOULD RESULT IN SCT/WIDESPREAD SHOWERS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 255 AM CDT FRI APR 19 2013
RELATIVELY STRONG 925-850 MB WARM AIR ADVECTION AND ISENTROPIC
UPGLIDE ON THE 280-290 K SFCS SLATED TO MOVE ACROSS THE FORECAST
AREA BETWEEN 06Z SUN - 00Z MON. THE LOW LEVEL THERMODYNAMIC FORCING
IS AHEAD OF A SHORTWAVE TROUGH SLATED TO DROP SOUTHEAST OVER THE
NORTHERN PLAINS SUN AFTERNOON...AND BE A PLAYER IN PCPN CHANCES FOR
THE REGION FOR THE EARLY PART OF THE NEW WORK WEEK. A FEW PIECES OF
UPPER LEVEL ENERGY AHEAD OF THE TROUGH...WHICH WOULD ADD TO THE
FORCING MIX FOR SUN. WEST-EAST RUNNING X-SECTION POINTS TO
INCREASING SATURATION BY 06Z SUN...DEEP ENOUGH AND COLD ENOUGH FOR
THERE TO BE ICE IN THE CLOUD. PRETTY GOOD CHANCE FOR SOME PCPN WITH
THE LOW LEVEL FORCING...WITH A SNOW/RAIN MIX INITIALLY CHANGING OVER
TO RAIN DURING THE DAY SUNDAY. A HINT OF INSTABILTY IN NAM BUFKIT
SOUNDINGS...BUT NOT MUCH/IF ANY IN THE GFS. WILL KEEP THUNDER
MENTION OUT OF THE FORECAST FOR NOW.
THE TROUGH/S SFC LOW/COLD FRONT SWING IN SUN NIGHT. GFS AND NAM AT
ODDS WITH THE TIMING...WITH THE 19.00Z NAM BRINGING THE FRONT TO THE
MISSISSIPPI RIVER AROUND 03Z MON...WITH THE GFS HOLDING OFF UNTIL
CLOSER TO 12Z MON. THE EC AND GEM ARE CLOSER TO THE GFS. WILL LIKELY
LEAN THIS WAY FOR TIMING. WITH SOME LOW LEVEL MOISTURE RETURN AHEAD
OF THE FRONT...IT WILL SERVE AS ANOTHER FOCUS FOR PCPN GENERATION.
THE GFS AND EC SWING BITS OF UPPER LEVEL ENERGY ACROSS THE REGION
SUN NIGHT-TUE NIGHT...AHEAD OF AN UPPER LEVEL TROUGH WHICH MOVES
OVER THE UPPER MISSISSIPPI RIVER VALLEY TUE NIGHT. THE UPPER LEVEL
FORCING WILL INTERACT WITH A SLOW MOVING NORTH-SOUTH RUNNING FRONTAL
BOUNDARY TO PRODUCE AREAS OF PCPN. MOST WOULD FALL AS RAIN...BUT
SOME MIX WITH AND THEN CHANGE OVER TO SNOW AS THE TROUGH EXITS LATE
TUE NIGHT IS LIKELY.
A BRIEF BREAK ON WED AS HIGH PRESSURE BUILDS IN...BUT IT JUST AS
QUICKLY EXITS SOUTHEAST ALLOWING FOR ANOTHER UPPER LEVEL SHORTWAVE
TROUGH TO DROP IN FROM THE NORTHWEST. GFS/EC BOTH IN AGREEMENT WITH
SPINNING THIS FEATURE ACROSS THE REGION WED NIGHT-THU...WITH MORE
LIGHT PCPN CHANCES RESULTING. MOSTLY RAIN...BUT THERE WOULD BE SOME
SNOW CHANCES TOO.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 644 AM CDT FRI APR 19 2013
CYCLONIC FLOW AROUND A LOW PRESSURE SYSTEM OVER UPPER MICHIGAN
WILL KEEP MVFR CLOUDS IN PLACE ACROSS THE REGION THROUGH 20.07Z.
IN ADDITION...THERE WILL BE ENOUGH INSTABILITY FOR SCATTERED
RAIN AND SNOW SHOW ERRS. THESE SHOWERS WILL OCCASIONALLY REDUCE
VISIBILITIES TO LESS THAN A MILE. WITH UNCERTAINTY ON WHEN THEY
WOULD AFFECT THE TAF SITES...THIS WAS NOT INCLUDED IN THE
FORECAST. 850 MB TO 950 MB LAPSE RATES WILL ALLOW 25 TO 30 KNOTS
WIND GUSTS TO MIX DOWN TO THE SURFACE THROUGH 20.04Z.
AS HIGH PRESSURE BUILDS ACROSS THE REGION AFTER 20.06Z...SKIES
WILL QUICKLY CLEAR.
&&
.HYDROLOGY...
ISSUED AT 255 AM CDT FRI APR 19 2013
FLOODING IS CURRENTLY OCCURRING ALONG PORTIONS OF THE BLACK AND
TREMPEALEAU RIVERS. RECENT RAINFALL WILL KEEP THOSE RIVERS ABOVE
FLOOD STAGE INTO THE EARLY WEEKEND.
WET CONDITIONS WILL PERSIST INTO THE EARLY PART OF THE NEW WORK
WEEK...BUT SIGNIFICANT ACCUMULATIONS ARE NOT EXPECTED THROUGH AT
LEAST MONDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION...BOYNE
HYDROLOGY....BOYNE/RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
255 AM CDT FRI APR 19 2013
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 255 PM CDT THU APR 18 2013
LATEST WATER VAPOR SATELLITE IMAGERY PLACED A SHORTWAVE TROUGH OVER
THE REGION...WITH TRENDS DRIVING IT EAST/NORTHEAST. GOOD MID LEVEL
DRY PUNCH ALSO INDICATED...WHICH SHOWS UP IN THE RAP BUFKIT
SOUNDINGS. THIS HAS RESULTED IN THE LOSS OF ICE IN SOME OF THE
CLOUD...AND MOSTLY AREAS OF DRIZZLE AHEAD OF TROUGH/UPPER LEVEL LOW.
DEPENDING ON SFC TEMPS...THERE COULD BE SOME PATCHY FREEZING
DRIZZLE. WEST-EAST RUNNING X-SECTION AND BUFKIT SOUNDINGS DO POINT
TO A RETURN OF THE ICE QUICKLY EARLY THIS MORNING...AND THUS EITHER
SNOW OR RAIN. GIVEN THE MOVEMENT OF THE SYSTEM...THE BETTER CHANCES
FOR ACCUMULATING PCPN WILL BE ACROSS THE NORTH...AND MOSTLY THIS
MORNING.
FOR THE AFTERNOON...RAP SOUNDINGS BUILD SOME SHALLOW NEAR SFC
INSTABILITY...UP TO AROUND 800 MB. 1000-850 MB LAPSE RATES ARE
AROUND 8.5 C/KM. ENOUGH LOW LEVEL SATURATION THAT THIS INSTABILITY
SHOULD RESULT IN SCT/WIDESPREAD SHOWERS.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 255 AM CDT FRI APR 19 2013
RELATIVELY STRONG 925-850 MB WARM AIR ADVECTION AND ISENTROPIC
UPGLIDE ON THE 280-290 K SFCS SLATED TO MOVE ACROSS THE FORECAST
AREA BETWEEN 06Z SUN - 00Z MON. THE LOW LEVEL THERMODYNAMIC FORCING
IS AHEAD OF A SHORTWAVE TROUGH SLATED TO DROP SOUTHEAST OVER THE
NORTHERN PLAINS SUN AFTERNOON...AND BE A PLAYER IN PCPN CHANCES FOR
THE REGION FOR THE EARLY PART OF THE NEW WORK WEEK. A FEW PIECES OF
UPPER LEVEL ENERGY AHEAD OF THE TROUGH...WHICH WOULD ADD TO THE
FORCING MIX FOR SUN. WEST-EAST RUNNING X-SECTION POINTS TO
INCREASING SATURATION BY 06Z SUN...DEEP ENOUGH AND COLD ENOUGH FOR
THERE TO BE ICE IN THE CLOUD. PRETTY GOOD CHANCE FOR SOME PCPN WITH
THE LOW LEVEL FORCING...WITH A SNOW/RAIN MIX INITIALLY CHANGING OVER
TO RAIN DURING THE DAY SUNDAY. A HINT OF INSTABILTY IN NAM BUFKIT
SOUNDINGS...BUT NOT MUCH/IF ANY IN THE GFS. WILL KEEP THUNDER
MENTION OUT OF THE FORECAST FOR NOW.
THE TROUGH/S SFC LOW/COLD FRONT SWING IN SUN NIGHT. GFS AND NAM AT
ODDS WITH THE TIMING...WITH THE 19.00Z NAM BRINGING THE FRONT TO THE
MISSISSIPPI RIVER AROUND 03Z MON...WITH THE GFS HOLDING OFF UNTIL
CLOSER TO 12Z MON. THE EC AND GEM ARE CLOSER TO THE GFS. WILL LIKELY
LEAN THIS WAY FOR TIMING. WITH SOME LOW LEVEL MOISTURE RETURN AHEAD
OF THE FRONT...IT WILL SERVE AS ANOTHER FOCUS FOR PCPN GENERATION.
THE GFS AND EC SWING BITS OF UPPER LEVEL ENERGY ACROSS THE REGION
SUN NIGHT-TUE NIGHT...AHEAD OF AN UPPER LEVEL TROUGH WHICH MOVES
OVER THE UPPER MISSISSIPPI RIVER VALLEY TUE NIGHT. THE UPPER LEVEL
FORCING WILL INTERACT WITH A SLOW MOVING NORTH-SOUTH RUNNING FRONTAL
BOUNDARY TO PRODUCE AREAS OF PCPN. MOST WOULD FALL AS RAIN...BUT
SOME MIX WITH AND THEN CHANGE OVER TO SNOW AS THE TROUGH EXITS LATE
TUE NIGHT IS LIKELY.
A BRIEF BREAK ON WED AS HIGH PRESSURE BUILDS IN...BUT IT JUST AS
QUICKLY EXITS SOUTHEAST ALLOWING FOR ANOTHER UPPER LEVEL SHORTWAVE
TROUGH TO DROP IN FROM THE NORTHWEST. GFS/EC BOTH IN AGREEMENT WITH
SPINNING THIS FEATURE ACROSS THE REGION WED NIGHT-THU...WITH MORE
LIGHT PCPN CHANCES RESULTING. MOSTLY RAIN...BUT THERE WOULD BE SOME
SNOW CHANCES TOO.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1151 PM CDT THU APR 18 2013
THE FOCUS AT THE TAF SITES IS WITH THE BAND OF SNOW CURRENTLY
MOVING ACROSS SOUTH CENTRAL MINNESOTA AND WHETHER IT WILL CLIP RST
OR LSE. CURRENT TRENDS FAVOR THAT IT WILL MISS THEM TO THE NORTH
WITH JUST LIGHT SNOW AND/OR DRIZZLE POSSIBLE THROUGH THE NIGHT.
WITH THE SYSTEM STARTING TO LIFT TO THE NORTHEAST...THERE APPEARS
TO BE SOME DRYING OF THE LOW LEVEL AIR MASS WITH CONDITIONS
IMPROVING TO MVFR THROUGH MUCH OF IOWA AND SOUTHERN WISCONSIN.
BASED ON THIS...HAVE PLAYED A GENERAL IMPROVING TREND THROUGH
TOMORROW EVENING WITH CEILINGS COMING UP. IT DOES APPEAR AS THOUGH
THERE MAY BE SOME RAIN OR SNOW SHOWERS THAT DEVELOP IN THE LATE
MORNING TO AFTERNOON HOURS ALONG THE MISSISSIPPI RIVER...BUT
CONFIDENCE IS NOT HIGH ENOUGH AT THIS POINT TO PUT IN SOME TRENDS
FOR LOWER VISIBILITIES THAT WOULD LIKELY LAST FOR A HALF HOUR AT A
TIME. SEEMS LIKE A SCENARIO WHERE TEMPO GROUPS WOULD BE NECESSARY
FOR SOME POTENTIAL BRIEF IFR CONDITIONS.
&&
.HYDROLOGY...
ISSUED AT 255 AM CDT FRI APR 19 2013
FLOODING IS CURRENTLY OCCURRING ALONG PORTIONS OF THE BLACK AND
TREMPEALEAU RIVERS. RECENT RAINFALL WILL KEEP THOSE RIVERS ABOVE
FLOOD STAGE INTO THE EARLY WEEKEND.
WET CONDITIONS WILL PERSIST INTO THE EARLY PART OF THE NEW WORK
WEEK...BUT SIGNIFICANT ACCUMULATIONS ARE NOT EXPECTED THROUGH AT
LEAST MONDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION.....HALBACH
HYDROLOGY....BOYNE/RIECK
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1138 PM MDT SAT APR 20 2013
.UPDATE...
ISSUED AT 1137 PM MDT SAT APR 20 2013
WILL ALLOW THE WINTER WEATHER ADVISORY FOR COLORADO PUBLIC ZONE 60
EXPIRE AT MIDNIGHT. ALSO...ADJUSTED SEVERAL GRIDS/ZONES TO REFLECT
LATEST NEAR TERM METEOROLOGICAL CONDITIONS.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 312 PM MDT SAT APR 20 2013
SHORTWAVE PUSHING EASTWARD ACROSS COLORADO THIS AFTERNOON WAS
PRODUCING A GOOD DEAL OF VIRGA/LIGHT SHOWERS OVER THE
MOUNTAINS...THOUGH AMOUNT OF PRECIP REACHING THE GROUND IS LIKELY
MUCH LESS THAN RADAR SUGGESTS. HAVE EVEN SEE A COUPLE LIGHTNING
STRIKES OVER THE SRN SAN LUIS VALLEY NEAR THE NM BORDER...AS
LAPS/HRRR SUGGEST A LOCAL MAX OF INSTABILITY OVER THE VALLEY. NOT
SEEING MUCH SNOW YET ON CENTRAL MOUNTAIN WEB CAMS...THOUGH WILL KEEP
SNOW ADVISORY IN PLACE THE NEXT FEW HOURS TO ACCOUNT FOR SOME BRIEF
BURSTS OF SNOW UNDER HEAVIER CONVECTIVE SHOWERS. ELSEWHERE...WILL
KEEP SCATTERED POPS OVER THE MOUNTAINS INTO THE EVENING...WITH SOME
ISOLATED POPS FOR MAINLY VIRGA/SPRINKLES ALONG THE I-25 CORRIDOR.
COULD ALSO SEE SOME BRIEF GUSTY/ERRATIC WINDS OVER LOWER ELEVATIONS
AS PRECIP EVAPORATES WITHIN THE DRY SUB-CLOUD LAYER. DIDN`T INCLUDE
A MENTION OF THUNDER IN ANY AREAS...AS LATEST HRRR KEEP BEST
INSTABILITY NORTH OF THE PALMER DIVIDE. EXPECT MOST PRECIP TO END
QUICKLY WITH SUNSET AS INSTABILITY WANES AND UPPER WAVE MOVES
RAPIDLY INTO THE CENTRAL PLAINS. ON SUNDAY...WEAK SHORTWAVE MAY
SPARK SOME VIRGA/SPRINKLES OVER THE MTNS...BUT COVERAGE WILL BE MUCH
LESS THAN TODAY. MODELS TRY TO BREAK OUT SOME SPRINKLES OVER THE FAR
EASTERN PLAINS AS WELL...AS MODEST LOW LEVEL MOISTURE RETURNS
NORTHWARD. WILL IGNORE THIS FOR NOW...AS ANY PRECIP WILL BE VERY
LIGHT. WEST WINDS WILL PICK UP MOST AREAS AS UPPER JET MOVES ACROSS
AND FLOW IN THE 500/700 MB LAYER INCREASES TO 30-40 KNOTS...AND
LOCATIONS ACROSS THE HIGHER ELEVATIONS OF THE SANGRES/SAWATCH RANGES
WILL BECOME FAIRLY GUSTY BY AFTERNOON. MAX TEMPS LOOK WARMER MOST
AREA WITH BETTER MIXING AND A SUBTLE RISE IN 700 MB TEMPS...THOUGH
AT BEST...READINGS WILL STILL COME UP A COUPLE DEGF SHORT OF
SEASONAL MAXES.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 312 PM MDT SAT APR 20 2013
...ANOTHER STRONG COLD FRONT TO AFFECT THE AREA MONDAY AFTERNOON
THROUGH TUESDAY...
SUNDAY NIGHT-TUESDAY...LATEST MODELS IN DECENT AGREEMENT ON
DEVELOPING SYNOPTIC PATTERN THROUGH THE PERIOD...THOUGH CONTINUE TO
DIFFER ON AMOUNTS OF GENERATED PRECIPITATION. AT ANY RATE...WILL SEE
INCREASING WESTERLY FLOW ALOFT ACROSS THE REGION SUNDAY NIGHT AS AN
EMBEDDED SHORT WAVE EJECTS ACROSS THE NORTHERN ROCKIES AHEAD OF
PARENT TROUGH DIGGING INTO THE NORTHERN GREAT BASIN. COULD SEE A FEW
SHOWERS ACROSS MAINLY THE CENTRAL MTS THROUGH THE PIKES PEAK REGION
EARLY SUNDAY EVENING WITH FIRST PASSING WAVE WITH AN ASSOCIATED LEE
TROUGH TRANSLATING ACROSS THE EASTERN PLAINS KEEPING OVERNIGHT LOWS
ON THE MILD SIDE.
MODERATE TO STRONG WEST TO SOUTHWEST FLOW ALOFT PERSISTS ACROSS
THE AREA MONDAY AS PARENT SYSTEM CONTINUES TO TRANSLATE ACROSS THE
ROCKIES WITH FLOW ALOFT BECOMING MORE WEST TO NORTHWEST MONDAY NIGHT
AND TUESDAY AS UPPER TROUGH CONTINUES TO LIFT OUT ACROSS THE CENTRAL
HIGH PLAINS. MID LEVEL MOISTURE SLOWLY INCREASES FROM WEST TO EAST
ACROSS THE AREA MONDAY MORNING WITH A STRONG BACKDOOR COLD PUSHING
ACROSS EASTERN COLORADO LATE MONDAY MORNING AND AFTERNOON. MODELS A
TAD SLOWER WITH FRONT AND HAVE WARMED UP HIGHS SOME ACROSS EASTERN
COLORADO...WITH THE WARMEST READINGS EXPECTED SOUTH AND WEST OF THE
HIGHWAY 50 CORRIDOR. WITH THE INCREASING OROGRAPHIC FLOW AND UVV
AHEAD OF WAVE...SHOULD SEE SNOW INCREASING IN COVERAGE AND INTENSITY
ACROSS THE CENTRAL MTS MONDAY MORNING AND SPREADING EAST ACROSS THE
UPPER ARKANSAS RIVER VALLEY INTO THE PIKES PEAK REGION THROUGH THE
EARLY AFTERNOON. MODEL SOUNDINGS INDICATING LOWER ELEVATIONS RAPIDLY
SATURATING BEHIND FRONT WITH RAIN DEVELOPING ALONG AND BEHIND THE
FRONT. RAIN BECOMES MIXED WITH AND CHANGES TO SNOW LATE IN THE
AFTERNOON AND EARLY EVENING...ESPECIALLY ACROSS THE PALMER
DVD...WITH A POSSIBLE MESSY MONDAY EVENING COMMUTE. MODELS DIFFER ON
AMOUNT OF QPF ACROSS THE SE MTS MONDAY NIGHT THOUGH AGREE ON A BAND
OF MODERATE PRECIP DEVELOPING ACROSS THE CENTRAL MTS THROUGH THE
PIKES REGION MONDAY NIGHT THROUGH EARLY TUESDAY MORNING AS RRQUAD OF
JET TRANSLATES ACROSS SOUTH CENTRAL COLORADO. MAY NEED SOME
HIGHLIGHTS ACROSS THE CENTRAL MTS AND POSSIBLE THE PIKES PEAK REGION
IF LATEST MODELS REMAIN TRUE. COOL UPSLOPE FLOW PERSISTS ACROSS THE
PLAINS ON TUESDAY...WITH HIGHS WELL BELOW SEASONAL
AVERAGES...ESPECIALLY ACROSS THE EASTERN PLAINS.
WEDNESDAY-SATURDAY...A WARMING TREND TO NEAR SEASONAL AVERAGES
EXPECTED THROUGH THE PERIOD AS MODERATE NORTHWEST FLOW ALOFT
PERSISTS ACROSS THE REGION. A FEW EMBEDDED SHORT WAVE PROGGED TO
TRANSLATE THROUGH THE FLOW THURSDAY AND FRIDAY...OWNING TO A FEW
AFTERNOON AND EVENING SHOWERS ACROSS MAINLY THE HIGHER TERRAIN.
&&
.AVIATION...ISSUED AT 1106 PM MDT SAT APR 20 2013
VFR CONDITIONS ARE EXPECTED TO CONTINUE FOR THE REMAINDER OF
TONIGHT AT THE KALS...KCOS AND KPUB TAF SITES.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR COZ060.
&&
$$
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1108 PM MDT SAT APR 20 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 312 PM MDT SAT APR 20 2013
SHORTWAVE PUSHING EASTWARD ACROSS COLORADO THIS AFTERNOON WAS
PRODUCING A GOOD DEAL OF VIRGA/LIGHT SHOWERS OVER THE
MOUNTAINS...THOUGH AMOUNT OF PRECIP REACHING THE GROUND IS LIKELY
MUCH LESS THAN RADAR SUGGESTS. HAVE EVEN SEE A COUPLE LIGHTNING
STRIKES OVER THE SRN SAN LUIS VALLEY NEAR THE NM BORDER...AS
LAPS/HRRR SUGGEST A LOCAL MAX OF INSTABILITY OVER THE VALLEY. NOT
SEEING MUCH SNOW YET ON CENTRAL MOUNTAIN WEB CAMS...THOUGH WILL KEEP
SNOW ADVISORY IN PLACE THE NEXT FEW HOURS TO ACCOUNT FOR SOME BRIEF
BURSTS OF SNOW UNDER HEAVIER CONVECTIVE SHOWERS. ELSEWHERE...WILL
KEEP SCATTERED POPS OVER THE MOUNTAINS INTO THE EVENING...WITH SOME
ISOLATED POPS FOR MAINLY VIRGA/SPRINKLES ALONG THE I-25 CORRIDOR.
COULD ALSO SEE SOME BRIEF GUSTY/ERRATIC WINDS OVER LOWER ELEVATIONS
AS PRECIP EVAPORATES WITHIN THE DRY SUB-CLOUD LAYER. DIDN`T INCLUDE
A MENTION OF THUNDER IN ANY AREAS...AS LATEST HRRR KEEP BEST
INSTABILITY NORTH OF THE PALMER DIVIDE. EXPECT MOST PRECIP TO END
QUICKLY WITH SUNSET AS INSTABILITY WANES AND UPPER WAVE MOVES
RAPIDLY INTO THE CENTRAL PLAINS. ON SUNDAY...WEAK SHORTWAVE MAY
SPARK SOME VIRGA/SPRINKLES OVER THE MTNS...BUT COVERAGE WILL BE MUCH
LESS THAN TODAY. MODELS TRY TO BREAK OUT SOME SPRINKLES OVER THE FAR
EASTERN PLAINS AS WELL...AS MODEST LOW LEVEL MOISTURE RETURNS
NORTHWARD. WILL IGNORE THIS FOR NOW...AS ANY PRECIP WILL BE VERY
LIGHT. WEST WINDS WILL PICK UP MOST AREAS AS UPPER JET MOVES ACROSS
AND FLOW IN THE 500/700 MB LAYER INCREASES TO 30-40 KNOTS...AND
LOCATIONS ACROSS THE HIGHER ELEVATIONS OF THE SANGRES/SAWATCH RANGES
WILL BECOME FAIRLY GUSTY BY AFTERNOON. MAX TEMPS LOOK WARMER MOST
AREA WITH BETTER MIXING AND A SUBTLE RISE IN 700 MB TEMPS...THOUGH
AT BEST...READINGS WILL STILL COME UP A COUPLE DEGF SHORT OF
SEASONAL MAXES.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 312 PM MDT SAT APR 20 2013
...ANOTHER STRONG COLD FRONT TO AFFECT THE AREA MONDAY AFTERNOON
THROUGH TUESDAY...
SUNDAY NIGHT-TUESDAY...LATEST MODELS IN DECENT AGREEMENT ON
DEVELOPING SYNOPTIC PATTERN THROUGH THE PERIOD...THOUGH CONTINUE TO
DIFFER ON AMOUNTS OF GENERATED PRECIPITATION. AT ANY RATE...WILL SEE
INCREASING WESTERLY FLOW ALOFT ACROSS THE REGION SUNDAY NIGHT AS AN
EMBEDDED SHORT WAVE EJECTS ACROSS THE NORTHERN ROCKIES AHEAD OF
PARENT TROUGH DIGGING INTO THE NORTHERN GREAT BASIN. COULD SEE A FEW
SHOWERS ACROSS MAINLY THE CENTRAL MTS THROUGH THE PIKES PEAK REGION
EARLY SUNDAY EVENING WITH FIRST PASSING WAVE WITH AN ASSOCIATED LEE
TROUGH TRANSLATING ACROSS THE EASTERN PLAINS KEEPING OVERNIGHT LOWS
ON THE MILD SIDE.
MODERATE TO STRONG WEST TO SOUTHWEST FLOW ALOFT PERSISTS ACROSS
THE AREA MONDAY AS PARENT SYSTEM CONTINUES TO TRANSLATE ACROSS THE
ROCKIES WITH FLOW ALOFT BECOMING MORE WEST TO NORTHWEST MONDAY NIGHT
AND TUESDAY AS UPPER TROUGH CONTINUES TO LIFT OUT ACROSS THE CENTRAL
HIGH PLAINS. MID LEVEL MOISTURE SLOWLY INCREASES FROM WEST TO EAST
ACROSS THE AREA MONDAY MORNING WITH A STRONG BACKDOOR COLD PUSHING
ACROSS EASTERN COLORADO LATE MONDAY MORNING AND AFTERNOON. MODELS A
TAD SLOWER WITH FRONT AND HAVE WARMED UP HIGHS SOME ACROSS EASTERN
COLORADO...WITH THE WARMEST READINGS EXPECTED SOUTH AND WEST OF THE
HIGHWAY 50 CORRIDOR. WITH THE INCREASING OROGRAPHIC FLOW AND UVV
AHEAD OF WAVE...SHOULD SEE SNOW INCREASING IN COVERAGE AND INTENSITY
ACROSS THE CENTRAL MTS MONDAY MORNING AND SPREADING EAST ACROSS THE
UPPER ARKANSAS RIVER VALLEY INTO THE PIKES PEAK REGION THROUGH THE
EARLY AFTERNOON. MODEL SOUNDINGS INDICATING LOWER ELEVATIONS RAPIDLY
SATURATING BEHIND FRONT WITH RAIN DEVELOPING ALONG AND BEHIND THE
FRONT. RAIN BECOMES MIXED WITH AND CHANGES TO SNOW LATE IN THE
AFTERNOON AND EARLY EVENING...ESPECIALLY ACROSS THE PALMER
DVD...WITH A POSSIBLE MESSY MONDAY EVENING COMMUTE. MODELS DIFFER ON
AMOUNT OF QPF ACROSS THE SE MTS MONDAY NIGHT THOUGH AGREE ON A BAND
OF MODERATE PRECIP DEVELOPING ACROSS THE CENTRAL MTS THROUGH THE
PIKES REGION MONDAY NIGHT THROUGH EARLY TUESDAY MORNING AS RRQUAD OF
JET TRANSLATES ACROSS SOUTH CENTRAL COLORADO. MAY NEED SOME
HIGHLIGHTS ACROSS THE CENTRAL MTS AND POSSIBLE THE PIKES PEAK REGION
IF LATEST MODELS REMAIN TRUE. COOL UPSLOPE FLOW PERSISTS ACROSS THE
PLAINS ON TUESDAY...WITH HIGHS WELL BELOW SEASONAL
AVERAGES...ESPECIALLY ACROSS THE EASTERN PLAINS.
WEDNESDAY-SATURDAY...A WARMING TREND TO NEAR SEASONAL AVERAGES
EXPECTED THROUGH THE PERIOD AS MODERATE NORTHWEST FLOW ALOFT
PERSISTS ACROSS THE REGION. A FEW EMBEDDED SHORT WAVE PROGGED TO
TRANSLATE THROUGH THE FLOW THURSDAY AND FRIDAY...OWNING TO A FEW
AFTERNOON AND EVENING SHOWERS ACROSS MAINLY THE HIGHER TERRAIN.
&&
.AVIATION...ISSUED AT 1106 PM MDT SAT APR 20 2013
VFR CONDITIONS ARE EXPECTED TO CONTINUE FOR THE REMAINDER OF
TONIGHT AT THE KALS...KCOS AND KPUB TAF SITES.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR COZ060.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
143 AM EDT SUN APR 21 2013
.AVIATION...
MOST OF THE CONVECTION THROUGH EARLY IN THE FORECAST WILL REMAIN
OFFSHORE AND ALONG THE STATIONARY FRONTAL BOUNDARY NEAR LAKE
OKEECHOBEE. SOME LOW CLOUDS HAVE DEVELOPED JUST TO THE SOUTH OF
THE BOUNDARY WITH IFR CIGS CURRENTLY AT KAPF AND COULD HAVE
TEMPORARY MVFR CIGS ALONG THE EAST COAST. THESE WILL LIKELY
PERSIST UNTIL AROUND 12-13Z. AFTERNOON CONVECTION IS AGAIN
EXPECTED AFT 18Z WITH MOVEMENT TOWARDS THE EAST COAST TERMINALS.
SURFACE WIND WILL BE DRAINAGE FLOW EARLY WITH SEA BREEZES
DEVELOPING ALONG BOTH COASTS AFT 15-17Z.
KOB
&&
.PREV DISCUSSION... /ISSUED 851 PM EDT SAT APR 20 2013/
UPDATE...
CONVECTION ENDED FOR THE EAST COAST EARLIER THIS EVENING. STORMS
RAPIDLY INTENSIFIED ONCE THEY HIT THE EAST COAST SEA BREEZE...WITH
A PEAK WIND GUST OF 72 MPH REPORTED NEAR HOLLYWOOD. TRANSVERSE
BANDS WERE EVIDENT IN VISIBLE SATELLITE IMAGERY EARLIER AS THE
NOSE OF THE SUBTROPICAL JET MOVED INTO THE GULF COAST. SHOWERS AND
EMBEDDED THUNDERSTORMS CONTINUE TO DEVELOP ALONG THE GULF
COAST...BUT THESE ARE EXPECTED TO BEGIN TO DIMINISH WITH THE LOSS
OF DAYTIME HEATING.
THE FRONTAL BOUNDARY MOVED INTO DEEP SOUTH FLORIDA BEFORE
STALLING LATE THIS AFTERNOON. IT IS BEGINNING TO WASH OUT
NOW...BUT A LOW LEVEL TROUGH WILL REMAIN ACROSS OR NEAR THE REGION
THROUGH MONDAY. THE UPPER LEVEL TROUGH WAS ACROSS THE GULF...BUT
THIS WILL MOVE EAST ON SUNDAY...WITH COOLER TEMPERATURES ALOFT
OVER SOUTH FLORIDA.
OVERNIGHT TONIGHT...SCATTERED SHOWERS AND FEW THUNDERSTORMS MAY
DEVELOP OVER THE GULF WATERS AHEAD OF THE UPPER TROUGH AND THE
SUBTROPICAL JET. UPPER LEVEL IMPULSES ARE FORECAST TO MOVE ACROSS
THE EASTERN GULF AND ACROSS CENTRAL/SOUTH FLORIDA SUNDAY AFTERNOON
INTO SUNDAY NIGHT...WITH STRONG TO POSSIBLY A COUPLE LOW END
SEVERE STORMS POSSIBLE. STORM MOTION WILL BE ALMOST NIL...WITH
STORM MOVEMENT DICTATED MOSTLY BY OUTFLOW AND SEA BREEZE
BOUNDARIES.
PREV DISCUSSION... /ISSUED 814 PM EDT SAT APR 20 2013/
AVIATION...
ALTHOUGH THE STRONG TO SEVERE THUNDERSTORMS THAT DEVELOPED EARLIER
OVER THE EAST COAST HAVE SHIFTED EAST OVER THE ATLANTIC WATERS AND
WEAKENED...ADDITIONAL SHOWERS AND STORMS HAVE DEVELOPED JUST
INLAND OF THE APF TERMINAL THIS EVENING. THIS ACTIVITY SHOULD
REMAIN JUST INLAND OF THE TERMINAL THROUGH THE MID EVENING HOURS
BEFORE TRENDING DOWN. OVERNIGHT...ANOTHER WEAK IMPULSE ALOFT
CURRENTLY LOCATED WEST OF THE FL PENINSULA OVER THE EASTERN GULF
COULD GENERATE ADDITIONAL SHOWERS AND STORMS LATER TONIGHT INTO
SUNDAY MORNING OVER THE GULF WATERS AND COASTAL AREAS INCLUDING
APF. HOWEVER...CONFIDENCE IS LOW AT THIS TIME DUE TO MODEL
DIFFERENCES BETWEEN THE HRRR AND WRF OUTPUT. AS A RESULT...WE WILL
INCLUDE MAINLY VCSH OVERNIGHT AND MONITOR THE ACTIVITY OVER THE
GULF FOR THE 06Z PACKAGE. LATER TOMORROW...MEAN LOW-LEVEL FLOW
WILL REMAIN LIGHT OUT OF THE SW. THIS FLOW COMBINED WITH WEAK
UPPER PULSES PASSING OVERHEAD AND THE EAST COAST SEA BREEZES WILL
BE ENOUGH TO SUPPORT THE POTENTIAL FOR ANOTHER ROUND OF
STRONG/SEVERE THUNDERSTORMS THROUGH THE AFTERNOON PERIOD TOMORROW
ALONG THE EAST COAST.
PREV DISCUSSION... /ISSUED 217 PM EDT SAT APR 20 2013/
DISCUSSION...
SATURDAY THROUGH MONDAY...
IN THE SHORT TERM FOR THIS AFTERNOON AND EVENING THERE IS NOT MUCH
CHANGE FROM THE PREVIOUS THINKING. THE SHOWERS AND THUNDERSTORMS
OVER THE ATLANTIC WATERS HAVE DIMINISHED IN COVERAGE BUT A FEW
SHOWERS ARE BEGINNING TO DEVELOP ALONG THE SEA BREEZE EXTENDING FROM
SOUTH MIAMI-DADE TO COASTAL PALM BEACH COUNTY AS WELL AS WEST OF
LAKE OKEECHOBEE ASSOCIATED WITH THE FRONT ITSELF. THIS PATTERN IS
CONSISTENT WITH THE FORECAST OF HIGH RESOLUTION MODELS FOR THIS
AFTERNOON AND EVENING. FAVORING FACTORS FOR THE FORMATION OF SHOWERS
AND THUNDERSTORMS ALONG THE EAST COAST ARE: THE WEAK SOUTHWESTERLY
FLOW AND THE TROUGH OF LOW PRESSURE NEAR THE FLORIDA EAST COAST. THE
LIMITING FACTORS ARE THE WARM 500 MB TEMPERATURES AND THE CAP AROUND
15KFT. IT IS POSSIBLE THAT ONCE THE ACTIVITY ALONG THE SEA BREEZE
REACHES THE CAP IT COULD DIMINISH IN INTENSITY BUT STILL PRODUCE
HEAVY RAINS, GUSTY WINDS, AND LIGHTNING. IN OTHER WORDS, IT COULD
START ACTIVE IN THE NEXT FEW HOURS AND THEN WEAKEN A BIT AS THE
STORMS START REACHING THE CAP. THE ADVANCE OF THE FRONT IS ALSO A
FAVORABLE FACTOR THAT IT COULD BECOME MORE IMPORTANT AS THE DAY
PROGRESSES. THE STEERING FLOW WILL MOVE STORMS GENERALLY FROM WEST
TO EAST. THIS WILL INCREASE THE POTENTIAL FOR THUNDERSTORMS FOR
THE EAST COAST.
THE CURRENT 500 MB PATTERN SHOWS A TROUGH OF LOW PRESSURE OVER THE
EASTERN AND CENTRAL US AND A STRONG BLOCKING RIDGE OF HIGH PRESSURE
OVER THE WESTERN ATLANTIC. AS THE HIGH CONTINUES TO MOVE FURTHER
EAST COOLER 500 MB TEMPERATURES WILL SPREAD OVER SOUTH FLORIDA ON
SUNDAY. THIS IS EXPECTED TO INCREASE THE POTENTIAL FOR STRONG OR
EVEN SEVERE STORMS ON SUNDAY IF HEATING IS FAVORABLE.
LONG TERM /TUESDAY THROUGH FRIDAY/...
BEHIND THE SURFACE TROUGH...A MORE TYPICAL SPRING WEATHER REGIME
WILL TAKE HOLD OVER FLORIDA...WITH EASTERLY LOW-LEVEL FLOW AND
HIGH PRESSURE BUILDING BOTH NEAR SURFACE AND ALOFT. ISOLATED
MAINLY DIURNAL SHOWERS ARE EXPECTED...WITH PARTLY TO MOSTLY SUNNY
SKIES AND TEMPERATURES REMAINING SLIGHTLY ABOVE AVERAGE.
AVIATION...ISSUED AT 147 PM EDT SAT APR 20 2013...
SHOWERS AND THUNDERSTORMS ARE BEGINNING TO SAG INTO THE NORTHWEST
INTERIOR AREAS. WITH AN ESTABLISHED GULF COAST SEA BREEZE...THIS
ACTIVITY SHOULD CONTINUE TO PUSH TO THE EAST. ADDITIONAL
CONVECTION WILL ALSO BE POSSIBLE ACROSS THE EAST COAST TERMINALS
OVER THE NEXT FEW HOURS OF PEAK HEATING. KEPT TEMPO GROUPS AT ALL
EAST COAST SITES FROM 20Z-23Z. WILL AMEND IF NECESSARY.
MARINE...
LONG-FUSED ADVISORIES AND WARNINGS ARE NOT EXPECTED THIS WEEKEND
OR NEXT WEEK OVER THE WATERS. LOCALLY HIGH WAVES AND WINDS CAN BE
EXPECTED IN SCATTERED TO NUMEROUS THUNDERSTORMS TODAY THROUGH
MONDAY...AND SPECIAL MARINE WARNINGS MAY BE ISSUED FROM TIME TO
TIME.
FIRE WEATHER...
MINIMUM RELATIVE HUMIDITY VALUES WILL BE ABOVE 50 PERCENT THIS
WEEKEND AND EARLY NEXT WEEK...AS MOIST ATMOSPHERE CONTRIBUTES TO
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. WINDS WILL MAINLY
SOUTH TODAY...BUT TRANSITION TO THE NORTHEAST TONIGHT AS COLD FRONT
MOVES IN. LOW WIND SPEEDS ARE EXPECTED OUTSIDE OF SHOWERS AND
THUNDERSTORMS.
PREV DISCUSSION... /ISSUED 947 AM EDT SAT APR 20 2013/
UPDATE...
SHOWERS AND THUNDERSTORMS OVER THE ATLANTIC WATERS HAVE DEVELOPED
THIS MORNING DUE TO THE CONVERGENCE OF SE FLOW OVER THE BAHAMAS
AND MORE SOUTHERLY FLOW OVER SOUTH FLORIDA. THE 12Z SOUNDING FROM
THIS MORNING SHOWS A CAP AROUND 650 MB ASSOCIATED WITH THE
SUBTROPICAL HIGH PRESSURE OVER THE ATLANTIC AND THE GULF. 500 MB
TEMPERATURES ARE AROUND -6C AND ARE NOT EXPECTED TO COOL BEYOND
-7C THIS AFTERNOON. HOWEVER, THE INFLUENCE OF A COLD FRONT MOVING
SOUTHWARD IS EXPECTED TO INTERACT WITH A WEAK EAST COAST SEA
BREEZE TO TRIGGER SHOWERS AND THUNDERSTORMS, ESPECIALLY IN PALM
BEACH AND BROWARD COUNTIES. SOME STORMS CAN ALSO EXTEND INTO
MIAMI-DADE. FOR THE WEST COAST THERE IS ONLY A SMALL CHANCE OF
THUNDERSTORMS, SINCE MOST OF THE SURFACE TROUGH IS ALIGNED FROM
NORTHEAST TO SOUTHWEST OVER THE ATLANTIC WATERS.
AS MENTIONED IN THE PREVIOUS DISCUSSION THE UPPER LEVEL
TEMPERATURES ARE FORECAST TO COOL ON SUNDAY ALLOWING FOR A GREATER
CHANCE OF THUNDERSTORMS THAN TODAY.
FOR TODAY THE HIGHEST POPS ARE STILL INCLUDED FOR PALM BEACH AND
BROWARD.
PREV DISCUSSION... /ISSUED 725 AM EDT SAT APR 20 2013/
AVIATION...
MOSTLY VFR CONDITIONS WILL OCCUR EARLY IN THE FORECAST ALTHOUGH
THERE COULD BE A BRIEF MVFR CIG AS A FEW SHOWERS MOVE ACROSS SOUTH
FLORIDA. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP BY THIS AFTERNOON AHEAD OF A WEAKENING COLD
FRONT THAT WILL SAG ACROSS THE REGION. THE HRRR INDICATES
CONVECTION TO BEGIN DEVELOPING IN EARNEST BETWEEN 18-20Z WITH THE
STEERING FLOW TAKING THE STORMS TO THE EAST COAST. THEREFORE, HAVE
LEFT TEMPO 18-22Z FOR ALL EAST TERMINALS WITH SOME OF THE ACTIVITY
POSSIBLY PERSISTING BEYOND THIS TIME FRAME. SURFACE WINDS ARE
QUESTIONABLE WITH A SLOW MOVING FRONTAL BOUNDARY BUT GENERALLY
SSW-SSE AHEAD OF THE FRONT AND NE BEHIND THE FRONT.
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
111 AM EDT FRI APR 19 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL MOVE ACROSS CENTRAL NORTH CAROLINA THIS
AFTERNOON AND EVENING...BRINGING WITH IT HEAVY RAIN AND THE CHANCE
FOR SEVERE THUNDERSTORMS. BEHIND THE FRONT...COOLER AND DRIER
CONDITIONS WILL MOVE IN FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 1030 AM FRIDAY...
OBSERVATIONS SHOW THE INGREDIENTS COMING TOGETHER FOR A POTENTIALLY
SEVERE THUNDERSTORM EVENT ACROSS CENTRAL NORTH CAROLINA LATER THIS
AFTERNOON AND INTO THE EVENING. AIDED BY THE DEVELOPMENT OF A 50
KNOT LOW LEVEL GET AT 850 THROUGH 700 MB...MOISTURE HAS BEGUN TO
INCREASE ACROSS THE AREA AND TEMPERATURES RISING INTO THE LOW TO MID
70S HAS BEGUN TO ERODE ANY LEFTOVER CIN FROM THE OVERNIGHT HOURS AND
INSTABILITY IS BEGINNING TO INCREASE. RADAR TRENDS SHOW SOME
CONVECTIVE DEVELOPMENT ALONG THE COASTAL AREAS AS WELL AS SOME
SMALLER SHOWERS BREAKING OUT BACK ACROSS THE WESTERN PIEDMONT IN
ADVANCE OF THE MAIN LINE OF SHOWERS AND THUNDERSTORMS WHICH IS
CURRENTLY TREKKING THROUGH THE MOUNTAINS OF EASTERN TENNESSEE.
COMPARED TO HIGH RESOLUTION MODELS IT APPEARS THE ACTUAL STORM
SYSTEM MAY BE AN HOUR OR TWO AHEAD OF SCHEDULE. FOR THE TIMING
ACROSS THE CWA WILL MOVE UP THE TIME FRAME TO NEAR 21Z (5 PM) IN THE
TRIAD...00Z (8 PM) FOR THE TRIANGLE AND 03Z (11 PM) FOR THE I-95
CORRIDOR. DAMAGING WINDS AND HEAVY RAIN ARE STILL THE PRIMARY
THREATS ASSOCIATED WITH THIS SYSTEM ALTHOUGH SMALL HAIL AND ISOLATED
TORNADOES WILL STILL BE POSSIBLE...ESPECIALLY IN THE SOUTH AND EAST
WHERE A LOOK AT RAP SOUNDINGS THROUGH BUFKIT SHOW INCREASED 0-1 KM
HELICITY. THIS WOULD ESPECIALLY BE A CONCERN IN ANY DISCREET CELLS
THAT DEVELOP OUT AHEAD OF THE LINE OF THUNDERSTORMS. GOES VISIBLE
SATELLITE IMAGERY SHOWS SOME BREAKS IN THE CLOUD COVER OVER SOUTH
CAROLINA BEGINNING TO ADVANCE NORTHWARD INDICATING THAT A GREATER
DIFFERENTIAL HEATING BOUNDARY MAY SET UP OVER THE CWA WITH HIGHER
MAX TEMPS IN THE SOUTH AND EAST (MIDDLE 80S) AS COMPARED TO THE
TRIAD (UPPER 70S). THIS BOUNDARY COULD BECOME A FOCUS FOR CONVECTION
LATER ON THIS EVENING. ONCE THE FRONT CLEARS TO THE EAST EXPECT
LINGERING ANAFRONTAL RAIN TO CONTINUE FOR SEVERAL HOURS. -ELLIS
OVERNIGHT LOWS ON FRIDAY NIGHT WILL BE DEPENDENT ON THE TIMING OF
THE EXITING PRECIP AND COMMENCEMENT OF COLD AIR ADVECTION. AT THIS
TIME...IT APPEARS PRECIP SHOULD CLEAR OUT OF AT LEAST THE WESTERN
PORTIONS OF THE FORECAST AREA BEFORE DAYBREAK AND THEREFORE AM
EXPECTING TEMPS TO RANGE FROM THE UPPER 40S/LOWER 50S ACROSS THE
WEST TO MID/UPPER 50S FURTHER EAST. CONDITIONS WILL IMPROVE
THROUGHOUT THE DAY ON SATURDAY AND WITH COLD AIR ADVECTION
PERSISTING...HIGHS SHOULD GENERALLY BE IN THE MID/UPPER 60S.-KRR
&&
.SHORT TERM /SATURDAY NIGHT AND SUNDAY/...
AS OF 250 AM FRIDAY...
CANADIAN SURFACE HIGH OVER THE UPPER GREAT LAKES WILL STRENGTHEN TO
+1040MB AS IT BUILDS EASTWARD...REACHING THE NEW ENGLAND COAST BY
SUNDAY NIGHT. THIS WILL KEEP IT SEASONABLY COOL AND DRY TO CLOSE THE
WEEKEND WITH LOW-LEVEL THICKNESSES A GOOD 20 TO 25 METERS BELOW
NORMAL WHICH SHOULD TRANSLATE INTO TEMPERATURES A GOOD 10 DEGREES
BELOW NORMAL. EARLY MORNING RISERS WILL NEED A JACKET SUNDAY MORNING
WITH MIN TEMPS 40 TO 45. HIGHS 60 TO 65 WITH BREEZY NELY WINDS
DEVELOPING BY THE AFTERNOON WITH COMPRESSION OF PRESSURE GRADIENT AS
OFFSHORE FRONTAL ZONE BEGINS TO SHARPEN UP.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 250 AM FRIDAY...
...BELOW NORMAL TEMPERATURES NEXT WEEK...
A WEAK MOISTURE DEPRIVED UPPER LEVEL DISTURBANCE IN ADVANCE OF A
MORE SIGNIFICANT NORTHERN STREAM TROUGH WILL QUIETLY MOVE
EASTWARD ACROSS SOUTHERN PLAINS/LOWER MS VALLEY SATURDAY NIGHT
THROUGH SUNDAY. BUT AS THE UPPER DISTURBANCE CROSSES THE SOUTHERN
APPALACHIANS AND MOVES OVER THE CAROLINAS SUNDAY NIGHT/MONDAY...WEAK
CYCLOGENESIS ALONG AN OLD BAROCLINIC FRONTAL ZONE SITTING OFF THE
SOUTHEAST COAST WILL BRING RENEWED VIGOR TO THE UPPER WAVE. RECENT
MODEL RUNS HAVE SHIFTED SLIGHTLY EASTWARD...KEEPING THE BULK OF THE
OVERRUNNING PRECIP ALONG THE IMMEDIATE COAST. WILL CONTINUE TO
MONITOR THIS SYSTEM...ESPECIALLY FOR ANY WESTWARD/INLAND TREND AS
ANY PRECIP FALLING INTO THE WEDGE OF STRONG HIGH PRESSURE EXTENDING
DOWN THE EASTERN SLOPES OF THE APPALACHIANS WILL RESULT IN A STRONG
CAD EVENT FOR MONDAY. FOR NOW WILL GO WITH JUST SLIGHT CHANCE POPS
IN THE EAST...KEEPING THE WESTERN TWO-THIRDS OF THE FORECAST AREA
DRY. TEMPERATURES MONDAY WILL NOT BE MUCH DIFFERENT THAN FROM SUNDAY
WITH LOWS MONDAY MORNING IN THE LOWER TO MID 40S. HIGHS IN THE
LOWER 60S...BUT COULD END UP SIGNIFICANTLY COOLER IF MODELS TREND
WETTER WITH FUTURE RUNS.
THE AFOREMENTIONED NORTHERN STREAM TROUGH AND ATTENDANT SFC COLD
FRONT WILL APPROACH THE AREA FROM THE WEST WEDNESDAY NIGHT/THURSDAY
BRINGING WIDESPREAD SHOWERS TO THE AREA WITH PERHAPS A CHANCE OF
THUNDER. TEMPERATURES WILL REBOUND BACK INTO THE 70S AHEAD OF THE
FRONT ON WEDNESDAY...AND THEN FALLING BACK TO BELOW NORMAL BEHIND
THE FRONTAL PASSAGE TO CLOSE THE WEEK.
&&
.AVIATION /18Z FRIDAY THROUGH TUESDAY/...
AS OF 110 PM FRIDAY...
24 HOUR TAF PERIOD: VERY HIGH CONFIDENCE OF SUB VFR CONDITIONS THIS
EVENING AS A COLD FRONT CROSSES THE AREA. PRIOR TO FRONTAL PASSAGE
MVFR CONDITIONS WILL LIFT OUT TO VFR FOR A PERIOD OF SEVERAL HOURS.
AHEAD OF THE FRONT EXPECT BREEZY CONDITIONS TO CONTINUE AS
OBSERVATIONS HAVE SHOW WINDS OF 15-20 KNOTS SUSTAINED GUSTING TO
NEAR 30 KNOTS. EXPECT A WEST TO EAST ADVANCE OF DETERIORATING
CONDITIONS WITH KINT AND KGSO AFFECTED BY THE FRONT BETWEEN 20Z AND
0Z. KRDU AND KFAY WILL SEE STORMS IN THE 22Z TO 2Z TIMEFRAME AND
FURTHER EAST AT KRWI BETWEEN 0Z AND 4Z. WIND GUSTS TO 40 KNOTS AND
POTENTIALLY HIGHER ARE POSSIBLE WITHIN STORMS. AFTER FRONTAL PASSAGE
EXPECT STRATIFORM RAIN TO CONTINUE FOR SEVERAL HOURS AT ALL SIGHTS
WITH CONDITIONS DETERIORATING AGAIN TO AT LEAST MVFR IF NOT LOWER.
RAIN SHOULD MOVE OUT BY SATURDAY MORNING AND CONDITIONS WILL RETURN
TO VFR. WINDS WILL BECOME NORTHWESTERLY AFTER FRONTAL PASSAGE NEAR
10 KNOTS.
LONG TERM: SPORADIC SUB-VFR EPISODES ARE POSSIBLE SUNDAY NIGHT
THROUGH WEDNESDAY. OTHERWISE VFR CONDITIONS ARE EXPECTED.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS/KRR
SHORT TERM...CBL
LONG TERM...CBL
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1033 AM EDT FRI APR 19 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL MOVE ACROSS CENTRAL NORTH CAROLINA THIS
AFTERNOON AND EVENING...BRINGING WITH IT HEAVY RAIN AND THE CHANCE
FOR SEVERE THUNDERSTORMS. BEHIND THE FRONT...COOLER AND DRIER
CONDITIONS WILL MOVE IN FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 1030 AM FRIDAY...
OBSERVATIONS SHOW THE INGREDIENTS COMING TOGETHER FOR A POTENTIALLY
SEVERE THUNDERSTORM EVENT ACROSS CENTRAL NORTH CAROLINA LATER THIS
AFTERNOON AND INTO THE EVENING. AIDED BY THE DEVELOPMENT OF A 50
KNOT LOW LEVEL GET AT 850 THROUGH 700 MB...MOISTURE HAS BEGUN TO
INCREASE ACROSS THE AREA AND TEMPERATURES RISING INTO THE LOW TO MID
70S HAS BEGUN TO ERODE ANY LEFTOVER CIN FROM THE OVERNIGHT HOURS AND
INSTABILITY IS BEGINNING TO INCREASE. RADAR TRENDS SHOW SOME
CONVECTIVE DEVELOPMENT ALONG THE COASTAL AREAS AS WELL AS SOME
SMALLER SHOWERS BREAKING OUT BACK ACROSS THE WESTERN PIEDMONT IN
ADVANCE OF THE MAIN LINE OF SHOWERS AND THUNDERSTORMS WHICH IS
CURRENTLY TREKKING THROUGH THE MOUNTAINS OF EASTERN TENNESSEE.
COMPARED TO HIGH RESOLUTION MODELS IT APPEARS THE ACTUAL STORM
SYSTEM MAY BE AN HOUR OR TWO AHEAD OF SCHEDULE. FOR THE TIMING
ACROSS THE CWA WILL MOVE UP THE TIME FRAME TO NEAR 21Z (5 PM) IN THE
TRIAD...00Z (8 PM) FOR THE TRIANGLE AND 03Z (11 PM) FOR THE I-95
CORRIDOR. DAMAGING WINDS AND HEAVY RAIN ARE STILL THE PRIMARY
THREATS ASSOCIATED WITH THIS SYSTEM ALTHOUGH SMALL HAIL AND ISOLATED
TORNADOES WILL STILL BE POSSIBLE...ESPECIALLY IN THE SOUTH AND EAST
WHERE A LOOK AT RAP SOUNDINGS THROUGH BUFKIT SHOW INCREASED 0-1 KM
HELICITY. THIS WOULD ESPECIALLY BE A CONCERN IN ANY DISCREET CELLS
THAT DEVELOP OUT AHEAD OF THE LINE OF THUNDERSTORMS. GOES VISIBLE
SATELLITE IMAGERY SHOWS SOME BREAKS IN THE CLOUD COVER OVER SOUTH
CAROLINA BEGINNING TO ADVANCE NORTHWARD INDICATING THAT A GREATER
DIFFERENTIAL HEATING BOUNDARY MAY SET UP OVER THE CWA WITH HIGHER
MAX TEMPS IN THE SOUTH AND EAST (MIDDLE 80S) AS COMPARED TO THE
TRIAD (UPPER 70S). THIS BOUNDARY COULD BECOME A FOCUS FOR CONVECTION
LATER ON THIS EVENING. ONCE THE FRONT CLEARS TO THE EAST EXPECT
LINGERING ANAFRONTAL RAIN TO CONTINUE FOR SEVERAL HOURS. -ELLIS
OVERNIGHT LOWS ON FRIDAY NIGHT WILL BE DEPENDENT ON THE TIMING OF
THE EXITING PRECIP AND COMMENCEMENT OF COLD AIR ADVECTION. AT THIS
TIME...IT APPEARS PRECIP SHOULD CLEAR OUT OF AT LEAST THE WESTERN
PORTIONS OF THE FORECAST AREA BEFORE DAYBREAK AND THEREFORE AM
EXPECTING TEMPS TO RANGE FROM THE UPPER 40S/LOWER 50S ACROSS THE
WEST TO MID/UPPER 50S FURTHER EAST. CONDITIONS WILL IMPROVE
THROUGHOUT THE DAY ON SATURDAY AND WITH COLD AIR ADVECTION
PERSISTING...HIGHS SHOULD GENERALLY BE IN THE MID/UPPER 60S.-KRR
&&
.SHORT TERM /SATURDAY NIGHT AND SUNDAY/...
AS OF 250 AM FRIDAY...
CANADIAN SURFACE HIGH OVER THE UPPER GREAT LAKES WILL STRENGTHEN TO
+1040MB AS IT BUILDS EASTWARD...REACHING THE NEW ENGLAND COAST BY
SUNDAY NIGHT. THIS WILL KEEP IT SEASONABLY COOL AND DRY TO CLOSE THE
WEEKEND WITH LOW-LEVEL THICKNESSES A GOOD 20 TO 25 METERS BELOW
NORMAL WHICH SHOULD TRANSLATE INTO TEMPERATURES A GOOD 10 DEGREES
BELOW NORMAL. EARLY MORNING RISERS WILL NEED A JACKET SUNDAY MORNING
WITH MIN TEMPS 40 TO 45. HIGHS 60 TO 65 WITH BREEZY NELY WINDS
DEVELOPING BY THE AFTERNOON WITH COMPRESSION OF PRESSURE GRADIENT AS
OFFSHORE FRONTAL ZONE BEGINS TO SHARPEN UP.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 250 AM FRIDAY...
...BELOW NORMAL TEMPERATURES NEXT WEEK...
A WEAK MOISTURE DEPRIVED UPPER LEVEL DISTURBANCE IN ADVANCE OF A
MORE SIGNIFICANT NORTHERN STREAM TROUGH WILL QUIETLY MOVE
EASTWARD ACROSS SOUTHERN PLAINS/LOWER MS VALLEY SATURDAY NIGHT
THROUGH SUNDAY. BUT AS THE UPPER DISTURBANCE CROSSES THE SOUTHERN
APPALACHIANS AND MOVES OVER THE CAROLINAS SUNDAY NIGHT/MONDAY...WEAK
CYCLOGENESIS ALONG AN OLD BAROCLINIC FRONTAL ZONE SITTING OFF THE
SOUTHEAST COAST WILL BRING RENEWED VIGOR TO THE UPPER WAVE. RECENT
MODEL RUNS HAVE SHIFTED SLIGHTLY EASTWARD...KEEPING THE BULK OF THE
OVERRUNNING PRECIP ALONG THE IMMEDIATE COAST. WILL CONTINUE TO
MONITOR THIS SYSTEM...ESPECIALLY FOR ANY WESTWARD/INLAND TREND AS
ANY PRECIP FALLING INTO THE WEDGE OF STRONG HIGH PRESSURE EXTENDING
DOWN THE EASTERN SLOPES OF THE APPALACHIANS WILL RESULT IN A STRONG
CAD EVENT FOR MONDAY. FOR NOW WILL GO WITH JUST SLIGHT CHANCE POPS
IN THE EAST...KEEPING THE WESTERN TWO-THIRDS OF THE FORECAST AREA
DRY. TEMPERATURES MONDAY WILL NOT BE MUCH DIFFERENT THAN FROM SUNDAY
WITH LOWS MONDAY MORNING IN THE LOWER TO MID 40S. HIGHS IN THE
LOWER 60S...BUT COULD END UP SIGNIFICANTLY COOLER IF MODELS TREND
WETTER WITH FUTURE RUNS.
THE AFOREMENTIONED NORTHERN STREAM TROUGH AND ATTENDANT SFC COLD
FRONT WILL APPROACH THE AREA FROM THE WEST WEDNESDAY NIGHT/THURSDAY
BRINGING WIDESPREAD SHOWERS TO THE AREA WITH PERHAPS A CHANCE OF
THUNDER. TEMPERATURES WILL REBOUND BACK INTO THE 70S AHEAD OF THE
FRONT ON WEDNESDAY...AND THEN FALLING BACK TO BELOW NORMAL BEHIND
THE FRONTAL PASSAGE TO CLOSE THE WEEK.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 720 AM FRIDAY...
24-HR TAF PERIOD:
WIDESPREAD MVFR CONDITIONS IN ASSOCIATION WITH STRONG S/SE LOW-LEVEL
MOISTURE ADVECTION IN ADVANCE OF THE STRONG COLD FRONT OVER THE TN
VALLEY WILL LIFT SLOWLY BETWEEN 15 TO 18Z. THEN BETWEEN 20Z FRI TO
06Z SAT...MVFR/IFR CONDITIONS ASSOCIATED WITH A LINE OF SHOWERS AND
THUNDERSTORMS WILL MOVE WEST TO EAST ACROSS THE AREA. ISOLD SEVERE
THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WIND GUSTS AOA 50 KT
WILL BE POSSIBLE WITH THE LINE OF STORMS. VFR CONDITIONS WILL THEN
SPREAD WEST TO EAST BETWEEN 06 TO 12Z SATURDAY MORNING AS DRIER AIR
FILTERS INTO THE AREA IN THE WAKE OF THE COLD FRONT PASSAGE.
A STEADY SOUTHERLY 10 KT WIND IS EXPECTED OVERNIGHT...BECOMING S/SW
AND INCREASING TO 15-20 KT WITH GUSTS UP TO 30 KT FRIDAY AFTERNOON
AS THE COLD FRONT PROGRESSES INTO WESTERN NC AND THE MSLP GRADIENT
TIGHTENS. WINDS WILL SHIFT TO THE NORTHWEST AT 10-15 KT WITH GUSTS
UP TO 20-25 KT IN THE WAKE OF THE COLD FRONTAL PASSAGE SATURDAY
MORNING.
LOOKING AHEAD:
VFR CONDITIONS ARE EXPECTED THROUGH SUNDAY AS STRONG HIGH PRESSURE
EXTENDS SOUTHWARD FROM NEW ENGLAND INTO THE CAROLINAS. BREEZY NE/ENE
WINDS WILL DEVELOP SUNDAY AFTERNOON AND ADVECT ATLANTIC MOISTURE
INTO THE REGION...RESULTING IN WIDESPREAD IFR/MVFR CEILINGS SUNDAY
NIGHT AND INTO MONDAY...ESPECIALLY AT THE EASTERN TERMINALS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...ELLIS
NEAR TERM...ELLIS/KRR
SHORT TERM...CBL
LONG TERM...CBL
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1147 PM CDT SAT APR 20 2013
.UPDATE...
ISSUED AT 1146 PM CDT SAT APR 20 2013
RADAR RETURNS HAVE MOVED INTO THE RED RIVER VALLEY BUT THE TREND
OF NOTHING REACHING THE GROUND CONTINUES. THERE ARE A FEW REPORTS
JUST OFF OF OUR SOUTHEASTERN COUNTIES NEAR LAKE TRAVERSE...BUT NOT
MUCH ELSE UNTIL THE MONTANA/NORTH DAKOTA BORDER. CONTINUED THE
TREND OF SLOWING DOWN POPS WITH THE BETTER CHANCES FOR PRECIP
COMING IN WITH THE MAIN FRONT DURING THE DAY TOMORROW. SREF SHOWS
SOME PROBABILITIES OF FZRA IN THE SOUTHWESTERN COUNTIES LATE
TONIGHT...BUT THINK PRECIP CHANCES ARE LOW ENOUGH AT THAT POINT TO
KEEP THINGS SNOW THEN RAIN/SNOW LATER ON TOMORROW.
UPDATE ISSUED AT 935 PM CDT SAT APR 20 2013
LIGHT SNOW BAND MOVING INTO THE NORTHWESTERN COUNTIES HAS FALLEN
APART WITH NOT MUCH REACHING THE GROUND. NAM AND RUC HAVE BACKED
OFF ON QPF FROM THE FIRST WAVE OF WARM ADVECTION PRECIP AND NOW
HAVE MOST OF THE PRECIP COMING IN LATER ON TONIGHT/TOMORROW
MORNING WITH THE MAIN TROUGH. LOWERED POPS FOR THE REST OF THE
EVENING TO 20-30 PERCENT AND SAVED THE HIGHER POPS FOR THE EARLY
MORNING HOURS IN THE FAR NORTHWEST WHEN MAIN SYSTEM ARRIVES.
LOWERED QPF/SNOW FOR TONIGHT ALSO.
UPDATE ISSUED AT 642 PM CDT SAT APR 20 2013
ONLY A FEW MINOR TWEAKS FOR THIS UPDATE AS A BAND OF LIGHT SNOW
SLOWLY ENTERS THE FAR NORTHWESTERN CWA THIS EVENING. BAND IS
NARROW AND SHORT LIVED AND THINK THE MORE SIGNIFICANT PRECIP WILL
BE WHEN THE MAIN TROUGH AXIS/FRONTAL BOUNDARY COMES OUT TOMORROW
MORNING. BUT NOT CONFIDENT ENOUGH TO MAKE CHANGES TO POPS AFTER
MIDNIGHT SO WILL HOLD OFF UNTIL THE 00Z MODEL RUNS START COMING
IN. INCREASED CLOUDS A BIT TONIGHT AND TWEAKED TEMPS...BUT NO HUGE
CHANGES.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 322 PM CDT SAT APR 20 2013
THE FORECAST CHALLENGE FOR THE SHORT TERM FOCUSES ON A COUPLE OF
ROUNDS OF SNOWFALL MOVING IN FROM THE WEST. IN GENERAL MODELS
STRUGGLE TO AGREE ON PLACEMENT OF PRECIPITATION...BUT COMPARING
CURRENT OBS/RADAR ECHOES TO 18Z VERIFICATION...I AM LEANING TOWARD
THE GFS. OPERATIONAL MODELS SHOW LOWERING CONDENSATION PRESSURE
DEFICITS MOVING IN TO WESTERN ZONES WITH MODEST ISENTROPIC LIFT
AFT 00Z...BY 06Z INTO THE RED RIVER VALLEY...AND ACROSS THE REGION
BY 12Z. BEFORE THIS MORE WIDESPREAD CLOUD COVER/PRECIP MOVES
IN...A TIGHT BAND OF SHOWERS WILL MOVE INTO THE WEST THIS EVENING.
DO EXPECT VERY LIGHT SNOW SHOWERS WITH THE INITIAL BAND...A BRIEF
BREAK...AND THEN MORE WIDESPREAD BUT LIGHT SNOW OVERNIGHT. PREFER A
SLIGHTLY LESS SATURATED GFS COMPARED TO THE NAM...AS ECHOES OVER
MONTANA HAVE NOT BEEN THAT IMPRESSIVE. BOTH MODELS ALSO SWEEP
PRECIP THROUGH RATHER QUICKLY AS ASSOCIATED FRONT MOVES INTO RED
RIVER VALLEY AROUND 18Z SUNDAY. DO EXPECT RAPID IMPROVEMENT AIDED
BY ISENTROPIC DESCENT TOMORROW AFTERNOON.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 322 PM CDT SAT APR 20 2013
ANOTHER WAVE WILL MOVE ACROSS THE CENTRAL PLAINS ON MONDAY...WITH
THE BEST CHANCE OF ANY MEASURABLE PRECIPITATION BEING ACROSS FAR
SOUTHERN ZONES. THE TUE NIGHT THROUGH SAT TIMEFRAME WILL CONTINUE WITH
TEMPS WELL BELOW NORMAL...WITH PERIODIC CHANCES FOR LIGHT QPF.
EACH MODEL RUN CONTINUES TO DELAY THE RIDGE ALOFT INTO THE
NORTHERN PLAINS...AND WARMER AIR...SO WILL HAVE TO SLIGHTLY LOWER
INHERITED TEMPS FOR ALL PERIODS. THE BEST CHANCES FOR PRECIP
APPEARS TO BE ON WED...WITH A RAIN/SNOW MIX CHANGING TO ALL SNOW
PERHAPS BY WED NIGHT. THE NW FLOW ALOFT AND PARADE OF SHORTWAVES
WILL CONTINUE WITH THE WARMEST DAY PERHAPS ON FRI/SAT...BUT
CONFIDENCE IS LOW WITH TEMPS LIKELY NOT GETTING TOO MUCH ABOVE THE
MID 40S AT ANY POINT. THERE ARE NO MAJOR PRECIP EVENTS IN SIGHT
EITHER...SO THE SLOW MELT CYCLE SHOULD CONTINUE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1146 PM CDT SAT APR 20 2013
VFR CEILINGS CONTINUE TO SPREAD ACROSS THE FORECAST AREA WITH MVFR
CIGS JUST TO OUR WEST. THINK THE LOWER CIGS WILL MOVE EASTWARD
AFTER 06Z TONIGHT INTO TOMORROW MORNING. SLOWED DOWN ANY PRECIP
MENTION AS MOST SNOW OR RAIN SHOULD BE WITH THE FRONTAL BOUNDARY
COMING IN DURING THE DAY TOMORROW. SOUTH WINDS WILL PICK UP TO
AROUND 15 KTS AND THEN SHIFT TO THE WEST AND NORTHWEST AS THE
FRONT COMES THROUGH. CIGS SHOULD RETURN TO VFR BY THE END OF
THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...JR
SHORT TERM...SPEICHER
LONG TERM...DK/SPEICHER
AVIATION...JR
AREA FORECAST DISCUSSION
NWS MIAMI FL
124 PM EDT SUN APR 21 2013
.AVIATION...
WIDELY SCATTERED SHOWERS AND A FEW THUNDERSTORMS ARE SEEN
CURRENTLY ON RADAR THIS AFTERNOON ACROSS SOUTHEAST FLORIDA WITH
THE VAST MAJORITY OF THUNDERSTORM ACTIVITY REMAINING OFFSHORE THE
ATLANTIC. LATEST HRRR KEEPS MOST OF THE ANTICIPATED ACTIVITY ALONG
THE EAST COAST THROUGH THE REMAINDER OF THE AFTERNOON AND EVENING.
ALSO LOOKS AS IF ANY FURTHER THUNDERSTORM DEVELOPMENT WILL BE
DRIVEN BY OUTFLOW BOUNDARIES WITH THE ABSENCE OF A GULF SEA BREEZE
THUS FAR. KEPT TEMPO GROUP FOR TSRA AT ALL EAST COAST TERMINALS
FROM 19Z-22Z.
&&
.PREV DISCUSSION... /ISSUED 928 AM EDT SUN APR 21 2013/
UPDATE...
A LINE OF SHOWERS AND THUNDERSTORMS ALREADY DEVELOPED THIS MORNING
AND IS MOVING OUT TO SEA. AFTER LOOKING AT CURRENT MESOSCALE MODEL
RUNS AND THEIR ANTICIPATED COVERAGE OF CONVECTION TODAY, HAVE
ADJUSTED POPS SOMEWHAT. BUFKIT MBE VECTORS SHOW SLOW MOVING AND/OR
TRAINING CELLS TODAY, WHICH WILL LEAD TO HEAVY PRECIP, ESPECIALLY
WITH PWAT OF AROUND 1.75 INCHES. CAPE ON THIS MORNINGS SOUNDING IS
NEAR 3100 JOULES. LIS ARE -7.7 AND THE FREEZING LEVEL IS NEAR 14K
FT AND THE -20 IS NEAR 23K FT. ALSO, THE CAP THAT WAS IN PLACE
YESTERDAY, IS ALL BUT ERODED. SO, KEPT WORDING FOR GUSTY WINDS,
HEAVY RAIN AND SMALL HAIL. THE SHEAR IS NOT GREAT, NOR IS THE
HELICITY, OF ONLY 14. SO, THOUGHT IS SOME STORMS MAY BE ABLE TO
BECOME SEVERE, THEY MAY BE PULSE TYPE WITH DAMAGING WINDS MOST
LIKELY, WITH HAIL NEXT. THIS IS IN AGREEMENT WITH THE SPC OUTLOOK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 71 83 71 82 / 40 50 20 20
FORT LAUDERDALE 73 83 73 83 / 40 50 20 20
MIAMI 73 84 72 84 / 40 50 20 20
NAPLES 70 84 67 87 / 40 50 10 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...13/SI
AVIATION/RADAR...10/CD