AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
900 PM PST FRI FEB 22 2008
.SYNOPSIS...SHOWERS HAVE MOVED EAST...BUT PATCHY FOG WILL LIKELY
REMAIN TONIGHT ON THE COASTAL SLOPES. GUSTY WINDS THIS EVENING IN
THE MOUNTAINS AND DESERTS. THERE WILL BE A BRIEF BREAK BETWEEN
SYSTEMS ON SATURDAY. THE NEXT PACIFIC STORM WILL BRING MORE RAIN
LATE SATURDAY NIGHT AND SUNDAY...WITH STRONG GUSTY WINDS IN THE
MOUNTAINS AND DESERTS. HIGH SURF WILL AFFECT THE COAST SUNDAY
AFTERNOON INTO TUESDAY. FAIR AND WARMER NEXT WEEK UNDER HIGH
PRESSURE.
&&
.DISCUSSION...FOR SOUTHWEST CALIFORNIA INCLUDING SAN DIEGO...
ORANGE...SOUTHWEST SAN BERNARDINO AND WEST RIVERSIDE COUNTIES.
.SHORT TERM (TONIGHT-SUN)...
THE SHOWERS HAVE MOVED EAST BUT A FAIRLY DEEP MOIST LAYER REMAINS
OVER THE AREA AND THE COASTAL SLOPES OF THE MTNS WILL LIKELY SEE
SOME FOG OVERNIGHT.
SUBSIDENCE AND A TIGHT WESTERLY PRESSURE GRADIENT WILL CAUSE LOCALLY
STRONG AND GUSTY WEST WINDS THROUGH THIS EVENING WITH LOCAL GUSTS TO
45-50 MPH IN THE MOUNTAINS AND ADJACENT DESERT SLOPES.
ON SATURDAY A WEAK SHORT WAVE RIDGE WILL BRING A BREAK IN THE
PRECIPITATION. RESIDUAL LOW LEVEL MOISTURE AND VARIABLE HIGH
CLOUDINESS WILL KEEP SKIES PARTLY CLOUDY.
THE NEXT SYSTEM WILL ARRIVE LATE SATURDAY NIGHT AND SUNDAY WITH MORE
RAIN. THREE BIG CONCERNS WITH THE NEXT STORM ARE: THE POSSIBILITY OF
ENOUGH MODERATE TO HEAVY RAIN...ESPECIALLY WITH THE FRONTAL PASSAGE
ON SUNDAY MORNING...TO CAUSE FLASH FLOODING/MUD AND ROCK SLIDES.
STRONG WINDS WITH GUSTS OVER 60 MPH IN PARTS OF THE MTNS AND
DESERTS...AND FINALLY THE ARRIVAL OF VERY LARGE SURF AT THE COAST.
FOR RAINFALL...CURRENT ESTIMATES ARE FOR AMOUNTS ABOUT ONE HALF TO
ONE INCH IN THE COAST AND VALLEYS...AND 1 TO 3 INCHES IN FOOTHILLS
AND MOUNTAINS WITH OROGRAPHIC PRECIP ENHANCEMENT ON THE WEST-FACING
SLOPES. SNOW LEVEL ABOUT 6500 TO 7000 FEET. THIS NEXT ROUND OF RAIN
COULD HAVE SIGNIFICANTLY HIGHER RUNOFF AMOUNTS DUE TO SATURATED
SOILS FROM ANTECEDENT STORMS...AND THIS COULD INCREASE OUR POTENTIAL
FOR FLOODING...MUD SLIDES AND DEBRIS FLOWS. THESE CONCERNS COULD
PROMPT THE LATER ISSUANCE OF A FLASH FLOOD WATCH PARTICULARLY FOR
THE BURN AREAS.
FOR WINDS...EVEN STRONGER WINDS WILL ACCOMANY THE NEXT STORM WITH
INCREASING SW FLOW SATURDAY NIGHT AHEAD OF THE COLD FRONT...AND
ESPECIALLY ON SUNDAY WHEN STRONG WESTERLY WINDS OCCUR DURING AND
AFTER FRONTAL PASSAGE. A HIGH WIND WATCH HAS BEEN POSTED FOR THE
MOUNTAINS AND DESERTS WITH SOLID POTENTIAL FOR DAMAGING GUSTS OVER
60 MPH.
&&
.LONG TERM (MON-FRI)...
UPPER RIDGING AND OFFSHORE FLOW WILL BRING FAIR AND WARMER WEATHER.
&&
.AVIATION...
230300Z...FAIRLY DEEP MOISTURE REMAINS BEHIND THE COLD FRONT THAT
PASSED THROUGH THE AREA EARLIER THIS AFTERNOON. MDCRS SOUNDINGS AS
WELL AS THE KNKX SOUNDING INDICATE THE TOP OF THE MOISTURE WAS
BETWEEN 7000 AND 8000 FEET OVER THE AREA. EXPECT LAYERS OF BROKEN CU
AND STRATOCU TO REMAIN OVER THE AREA THROUGH THE NIGHT. BASES SHOULD
RANGE BETWEEN 1500 FEET TO 4000 FEET MSL. THE LOWER LAYER SHOULD
BREAK UP DURING THE MORNING ON SATURDAY BUT OVERRUNNING MID AND HIGH
CLOUDS...MOSTLY AT OR ABOVE FL150...SHOULD SPREAD OVER THE AREA
DURING THE DAY ON SATURDAY AHEAD OF THE NEXT COLD FRONT DUE TO COME
THROUGH SUNDAY MORNING.
FAIRLY STRONG WEST WINDS ACROSS THE MOUNTAINS WILL RESULT IN
MOUNTAIN WAVE/ROTOR ACTIVITY ALONG THE EAST SIDES OF THE MOUNTAINS
OVER THE DESERT AREAS THROUGH THE EVENING VICINITY OF KPSP...KTRM
AND L08.
&&
.MARINE...
NEXT MARINE THREAT WILL BE WHEN THE NEXT LOW APPROACHES FROM THE
WEST SATURDAY NIGHT. WINDS LIKELY TO BE GUSTING FROM THE SOUTH OVER
25 KT WITH THIS FRONT. FOLLOWING THIS THE LARGE WEST SWELL
ARRIVES...AND EXPECTED TO COME IN AS A SWELL FRONT LATE SUNDAY
AFTERNOON AND EVENING WITH A RAPID INCREASE IN SEA HEIGHTS. MODELS
FOR PAST FOUR DAYS HAVE CONSISTENTLY BEEN ADVERTISING HEIGHT AND
TIMING AS A SOLID 16 TO 18 FEET AT 16 SECONDS BEGINNING SUNDAY
EVENING AND CONTINUING INTO MONDAY MORNING THEN SLOWLY SUBSIDING TO
AROUND 10 FEET MONDAY NIGHT. A COASTAL FLOOD STATEMENT REMAINS IN
PLACE ADDRESSING THE THREAT OF MODERATE BEACH EROSION AND DAMAGE TO
LOW LYING COASTAL STRUCTURES. ALSO ISSUED A MARINE WEATHER STATEMENT
ADDRESSING THE LARGE SWELLS OVER THE COASTAL WATERS. MARINERS SHOULD
ALSO BE PREPARED TO STAY OUT OR RETURN TO PORT PRIOR TO SUNDAY
AFTERNOON AS ENTERING AND EXITING MOST HARBORS AND BAYS WILL LIKELY
BE HAZARDOUS.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FOR THE SAN BERNARDINO...RIVERSIDE AND SAN DIEGO
COUNTY MOUNTAINS AND ADJACENT DESERTS UNTIL 1 AM PST TONIGHT.
SEE LAXNPWSGX.
HIGH WIND WATCH FOR THE SAN BERNARDINO...RIVERSIDE AND SAN DIEGO
COUNTY MOUNTAINS AND ADJACENT DESERTS FROM SATURDAY NIGHT THROUGH
SUNDAY EVENING. SEE LAXNPWSGX.
COASTAL HAZARD MESSAGE FOR LATE SUNDAY AND MONDAY DUE TO UNUSUALLY
HIGH SURF AND POSSIBLE BEACH EROSION. SEE LAXCFWSGX.
&&
$$
PUBLIC...PG
AVIATION...HORTON
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
300 PM MST SUN FEB 24 2008
.SHORT TERM...TONIGHT THROUGH TUESDAY...
STORM SYSTEM TAKING SHAPE OVER UTAH AND COLORADO THIS AFTERNOON WITH
SATELLITE AND RADAR IMAGES SHOWING ENHANCED CONVECTIVE STREAKS.
THIS WAS EXPECTED AS MODEL DATA SHOWED MID LEVEL THETAE LAPSE RATES
AROUND ZERO THIS AFTERNOON AND CONTINUING INTO THE EVENING HOURS.
VERY DYNAMIC SYSTEM WITH THE GFS/WRF MODELS SHOWING STRONG PACIFIC
JET STREAMING TOWARD SW COLORADO...QVECTORS DEPICTING SYNOPTIC SCALE
ASCENT...AND FRONTOGENESIS ACROSS ERN UTAH AS A DEVELOPING TROUGH
AXIS FORMS OVER THE CENTRAL ROCKIES (REPLACING THE FILLING LOW THAT
IS MOVING TOWARD SW OREGON.) THE HEAVIEST PCPN WILL BE TONIGHT...
COINCIDING WITH THE HIGHEST H7 SPECIFIC HUMIDITY VALUES.
HOW MUCH SNOW FALLS IN THE POST FRONTAL AIR MASS IS THE FORECAST
CHALLENGE AND HOW LONG TO HANG ONTO THE WINTER WEATHER WARNINGS AND
ADVISORIES. THE DEEPEST MOISTURE WILL BE EAST OF THE DIVIDE WITH THE
FLOW ALOFT BECOMING NORTHWEST. THIS WILL EFFECTIVELY SHUT DOWN THE
SWRN SAN JUAN MOUNTAINS (EXCEPT NEAR THE MOUNTAIN PASSES) AND
THEREFORE WILL ADJUST THE WARNING FOR ZONE 19 AND END IT AT MONDAY
NOON. ELSEWHERE...NORTHWEST WINDS ALOFT WILL NOT BE STRONG ENOUGH
FOR CONTINUING HEAVY SNOW FOR NORTHWEST FACING SLOPES...BUT 15 TO 20
KNOTS AT 700 MB IS SUFFICIENT FOR ACCUMULATION. ALSO LACKING IS THE
CONTINUED COLD ADVECTION IN THE POST FRONTAL ENVIRONMENT UNTIL THE
NEXT UPSTREAM SHORT WAVE (CURRENTLY OVER SRN BRITISH COLUMBIA) SWEEPS
ACROSS NORTHWEST COLORADO MONDAY NIGHT. THIS WAVE WILL ENHANCE
SNOWFALL OVER THE NRN AND CENTRAL MOUNTAINS. MONDAY NIGHT/S WAVE
WILL MISS THE ERN UTAH MOUNTAINS SO WILL DROP THOSE HEADLINES AT
MONDAY NOON.
TUESDAY...CLEARING CONDITIONS...MOST NOTABLY ACROSS ERN UTAH.
SCATTERED LIGHT OROGRAPHIC PCPN WILL LINGER TOWARD RABBIT EARS...
VAIL...AND MONARCH PASSES...BUT ACCUMULATING SNOWFALL WILL HAVE
ENDED. IN ADDITION...MONDAY NIGHTS SHORT WAVE MAY SCOUR OUT WHAT
REMAINS OF THE COLD TRAPPED AIR IN THE NRN VALLEYS. IF THAT IS THE
CASE...THEN VERNAL AND GUNNISON WILL BE A LITTLE WARMER THAN WHAT
THE BIAS CORRECTED GUIDANCE GRIDS HAVE SHOWN FOR THE PAST 2 TO 3
MONTHS.
.LONG TERM...TUESDAY NIGHT THROUGH SUNDAY...
NW FLOW CONTINUES TUE NIGHT WITH JET SEGMENT STILL OVER CO. SREF/GFS
MODELS KEEPS SOME CHANCE OF PRECIP IN THE NRN MTNS TUE NIGHT...
PROBABLY DUE TO NW OROGRAPHICS AND LINGERING SHALLOW MOISTURE AND
INSTABILITY. BUT WITH CROSS-SECTIONS SHOWING STABILITY RAPIDLY
INCREASING ABOVE MTN TOP LEVEL...WITH MAINTAIN NO MENTION OF PRECIP
IN THE FORECAST.
MODELS REMAIN IN GENERAL AGREEMENT OF A MEAN RIDGE OVER THE WEST
INTO SW CANADA WED-FRI. TEMPS WILL MODERATE. SACRIFICIAL SHORTWAVE
WORKS THROUGH THE RIDGE AND ACROSS ERN UT/WRN CO ABOUT THU FOR A
SLIGHT CHANCE OF PRECIP MAINLY IN THE NRN MTNS. THIS SHORTWAVE HELPS
WEAKEN THE RIDGE...WHICH IS FORECAST TO COLLAPSE SAT-SUN AHEAD OF A
STRONGER PACIFIC WAVE THAT MOVES INTO WA/OR STATES EARLY SAT...THEN
DROPS SEWD ACROSS THE CENTRAL ROCKIES ON SUN. MODEL DIFFERENCES WITH
THE DETAILS...SUCH AS THE ECMWF IS SHARPER...DEEPER AND A TAD
SLOWER WITH THE DIGGING TROUGH THAN THE GFS. BUT THE GENERAL TREND
SHOULD BE FOR INCREASING CHANCE OF CHANCE OF PRECIP LATE SAT-SUN...
AND HAVE REFLECTED SUCH IN THE GRIDDED FORECAST. THIS HAS THE
POTENTIAL FOR ANOTHER ROUND OF SIGNIFICANT SNOWFALL IN THE MTNS NEXT
WEEKEND.
&&
.AVIATION...
SW WINDS 40-50 KTS AT 11,000 FEET LATE THIS AFTERNOON AND EVENING
WILL RESULT IN A SPEED SHEAR ZONE NEAR MTN TOP LEVEL AS AIRCRAFT RISE
OUT OF SHELTERED VALLEY AIRPORTS. THE STRONG SW FLOW ALOFT BECOMES W
AND WEAKENS AFTER 06Z...AND THEN NW AFTER 12Z MON.
A SOMEWHAT DIFFUSE SW-NE ORIENTED FRONT WILL BE NEAR K4V0 AT 00Z AND
IS EXPECTED TO PUSH SE TO THE SAN JUAN MTNS BY 06Z...THEN OUT OF THE
AREA BY 12Z MON. MVFR TO IFR CONDITIONS TONIGHT WITH LOWER CIGS/VSBY
IN -SN/SN. MT TOPS WILL BECOME OBSCD. MAY HAVE -SHRA OR -SHRASN AT
VALLEY AIRPORTS THIS EVENING UNTIL THE FRONT PASSES.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
.CO...WINTER STORM WARNING FOR THE HIGH WESTERN COLORADO MOUNTAINS
THROUGH TUESDAY MORNING 6 AM...ZONES 4/9/10/12/13/18.
WINTER STORM WARNING FOR THE SOUTHWESTERN SAN JUAN MOUNTAINS
THROUGH MONDAY NOON...ZONE 19
SNOW AND BLOWING SNOW ADVISORY FOR THE LOWER MOUNTAINS OF
WESTERN COLORADO THROUGH MIDNIGHT MONDAY NIGHT...ZONES 3
AND 17.
SNOW ADVISORY FOR THE LOWER YAMPA RIVER BASIN UNTIL MIDNIGHT
TONIGHT...ZONE 1.
SNOW ADVISORY FOR THE CENTRAL YAMPA RIVER BASIN UNTIL MONDAY
NOON...ZONE 2.
SNOW ADVISORY FOR THE STEAMBOAT SPRINGS AREA UNTIL
TUESDAY MORNING 6 AM...ZONE 5.
.UT...SNOW AND BLOWING SNOW ADVISORY FOR THE MOUNTAINS OF EAST
UTAH FROM THROUGH MONDAY NOON...ZONES 23/25/28.
SNOW ADVISORY FOR THE EASTERN UINTA BASIN UNTIL MIDNIGHT
TONIGHT...ZONE 24.
$$
SHORT TERM...PF
LONG TERM....JAD
AVIATION.....JAD
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1007 PM EST SUN FEB 24 2008
.UPDATE...
UPDATED ZONE FORECASTS TO TAKE FLURRIES AND SPRINKLES OUT OF THE
EASTERN HALF OF THE AREA. THE PRECIPITATION HAS MOVED TO THE EAST
ALONG WITH THE SHORTWAVE TROUGH THAT TRIGGERED THE PRECIPITATION.
REST OF FORECAST IS ON TRACK WITH NO CHANGES.
&&
.PREVIOUS FORECAST ISSUED AT 220 PM EST...
SHORT TERM (TONIGHT AND MON)...
WHILE ANY MEASURABLE PRECIP IS LIKELY OVER IN THIS PERIOD...LO
CLOUDS WILL LINGER THRU TNGT INTO EARLY MON.
SHRTWV TROF EXITS E/NE TNGT WHILE PLAINS/MID MS VLY RIDGE REACHES
THE WRN OH VLY VLY BY 12Z MON AND ERN OH VLY BY 00Z TUE. AS RIDGE
MOVES ACROSS OUR FA MON...SOUTHERLY FLO ON THE BACKSIDE OF HI PRES
SHOULD GRADUALLY INCREASE RESULTING IN A LOSS OF OUR LO CLOUD DECK.
CIGS AROUND 1000 FEET ATTM WILL LIKELY CONTINUE TONIGHT WITH VERY
LIGHT WNW WINDS AT CLOUD LEVEL. IT MAY BE MIDDAY MON...BEFORE
LO CLOUDS MOVE OUT/DISSIPATE BASED ON LO LEVEL RH AND WIND
FIELDS.
ANY CLEARING WILL BE SHORT LIVED ON MON AS HIGH AND THEN MID LEVEL
MOISTURE(CLOUDS) INCREASE IN ADVANCE OF NEXT SYSTEM MON NIGHT. WILL
CONTINUE OPTIMISTIC AND WORD THE FCST AS BECOMING PARTLY SUNNY.
DO NOT EXPECT TEMPS TO LOWER MUCH TONIGHT WITH CLOUDS AND WINDS
PICKING UP A SLY COMPONENT TOWARD MORNING. WILL FORECAST MIN TEMPS
OVRNGT 2-4 DEGS LOWER THAN CURRENT READINGS.
LONG TERM (MONDAY NIGHT THROUGH SUNDAY)...
SURFACE LOW TRACKS THROUGH THE OHIO VALLEY MONDAY NIGHT AND TUESDAY
DRAGGING A COLD FRONT AND PRECIPITATION THROUGH THE CWA. SHOWERS
LIKELY ALREADY IN THE FORECAST AND BUMPED CHANCES INTO THE
CATEGORICAL RANGE. GOOD SHEAR ENVIRONMENT WITH FAST MOVING FRONT AND
STRONG LOW AND MID LEVEL JETS SO THUNDER CONTINUES TO LOOK LIKE A
GOOD IDEA FOR MONDAY NIGHT AND EARLY TUESDAY. BEHIND THE FRONT
TEMPERATURES PEAK EARLY TUESDAY AND FALL THROUGHOUT THE DAY WITH
RAIN CHANGING OVER TO SNOW SOMETIME DURING THE DAY...ESPECIALLY
ALONG THE NORTHERN AND EASTERN ZONES WHERE COLDEST AIR WORKS IN THE
FASTEST. BOTH GFS AND NAM INDICATING A PROLONGED PERIOD OF LIGHT
SNOW POTENTIAL AND HAVE INCREASED POPS TO LIKELY IN THE NORTHERN
TIER FOR TUESDAY NIGHT AND UP INTO THE HIGH CHANCE CATEGORY ON
WEDNESDAY. LINGERING FLURRIES MAY CONTINUE IN THE EAST WEDNESDAY
NIGHT...BEFORE ALL PRECIPITATION MOVES OFF BY EARLY THURSDAY.
ACCUMULATIONS AT THIS TIME APPEAR TO BE LIGHT...THOUGH SOME PLACES
COULD PICK UP AN INCH OR SO THROUGH THE ENTIRE 24-36 HOUR PERIOD OF
LIGHT SNOW SHOWERS FROM MIDDAY TUESDAY THROUGH LATE WEDNESDAY.
QUIET PERIOD THURSDAY THROUGH THE EARLY PART OF THE WEEKEND BEFORE A
BROAD UPPER TROUGH OVER THE WESTERN UNITED STATES RETURNS ACTIVE
SOUTHWEST FLOW ALOFT TO THE REGION BY LATE SUNDAY.
&&
.AVIATION (00Z TAFS)...
EXPECT LOW CLOUDS TO CONTINUE OVER MUCH OF CENTRAL KENTUCKY AND
SOUTH CENTRAL INDIANA OVERNIGHT WITH CIGS 1-2 THSD FEET AT SDF AND
LEX AND A LITTLE HIGHER AT BWG. BOTH MODEL TIME SECTIONS AND
AIRCRAFT SOUNDINGS INDICATE DEEP MOISTURE WAS OVER THE AREA BETWEEN
18Z AND 00Z. TIME SECTIONS SHOW ATMOSPHERE DRYING OUT IN THE MID AND
UPPER LEVELS OVERNIGHT BUT THE MOISTURE REMAINS HIGH IN THE LOWER
LEVELS. THUS WILL KEEP CIGS BELOW 2 THSD FT THROUGH MID MORNING
ACROSS THE NORTH WITH HIGHER CIGS AT BWG.
DURING THE DAY MONDAY...WINDS WILL BECOME MORE SOUTHERLY WITH TIME
SECTIONS INDICATED LOWER LEVEL OF ATMOSPHERE WILL CONTINUE TO DRY.
AS A RESULT LOWER CLOUDS WILL BEGIN TO LIFT AND MAY BECOME SCATTERED
IN THE AFTERNOON. HOWEVER BY THEN HIGHER CLOUDS AHEAD OF NEXT LOW
PRESSURE AREA WILL SPREAD OVER THE REGION.
THE PRECIPITATION FROM DURING THE DAY HAS MOVED TO THE EAST AND
SHOWERS FROM THE NEXT SYSTEM WILL HOLD OFF UNTIL AFTER 00Z.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
UPDATE.......SCHOLZ
SHORT TERM...DK
LONG TERM....MACZKO
AVIATION.....SCHOLZ
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
628 PM EST SUN FEB 24 2008
.SHORT TERM (TONIGHT AND MON)...
WHILE ANY MEASURABLE PRECIP IS LIKELY OVER IN THIS PERIOD...LO
CLOUDS WILL LINGER THRU TNGT INTO EARLY MON.
SHRTWV TROF EXITS E/NE TNGT WHILE PLAINS/MID MS VLY RIDGE REACHES
THE WRN OH VLY VLY BY 12Z MON AND ERN OH VLY BY 00Z TUE. AS RIDGE
MOVES ACROSS OUR FA MON...SOUTHERLY FLO ON THE BACKSIDE OF HI PRES
SHOULD GRADUALLY INCREASE RESULTING IN A LOSS OF OUR LO CLOUD DECK.
CIGS AROUND 1000 FEET ATTM WILL LIKELY CONTINUE TONIGHT WITH VERY
LIGHT WNW WINDS AT CLOUD LEVEL. IT MAY BE MIDDAY MON...BEFORE
LO CLOUDS MOVE OUT/DISSIPATE BASED ON LO LEVEL RH AND WIND
FIELDS.
ANY CLEARING WILL BE SHORT LIVED ON MON AS HIGH AND THEN MID LEVEL
MOISTURE(CLOUDS) INCREASE IN ADVANCE OF NEXT SYSTEM MON NIGHT. WILL
CONTINUE OPTIMISTIC AND WORD THE FCST AS BECOMING PARTLY SUNNY.
DO NOT EXPECT TEMPS TO LOWER MUCH TONIGHT WITH CLOUDS AND WINDS
PICKING UP A SLY COMPONENT TOWARD MORNING. WILL FORECAST MIN TEMPS
OVRNGT 2-4 DEGS LOWER THAN CURRENT READINGS.
.LONG TERM (MONDAY NIGHT THROUGH SUNDAY)...
SURFACE LOW TRACKS THROUGH THE OHIO VALLEY MONDAY NIGHT AND TUESDAY
DRAGGING A COLD FRONT AND PRECIPITATION THROUGH THE CWA. SHOWERS
LIKELY ALREADY IN THE FORECAST AND BUMPED CHANCES INTO THE
CATEGORICAL RANGE. GOOD SHEAR ENVIRONMENT WITH FAST MOVING FRONT AND
STRONG LOW AND MID LEVEL JETS SO THUNDER CONTINUES TO LOOK LIKE A
GOOD IDEA FOR MONDAY NIGHT AND EARLY TUESDAY. BEHIND THE FRONT
TEMPERATURES PEAK EARLY TUESDAY AND FALL THROUGHOUT THE DAY WITH
RAIN CHANGING OVER TO SNOW SOMETIME DURING THE DAY...ESPECIALLY
ALONG THE NORTHERN AND EASTERN ZONES WHERE COLDEST AIR WORKS IN THE
FASTEST. BOTH GFS AND NAM INDICATING A PROLONGED PERIOD OF LIGHT
SNOW POTENTIAL AND HAVE INCREASED POPS TO LIKELY IN THE NORTHERN
TIER FOR TUESDAY NIGHT AND UP INTO THE HIGH CHANCE CATEGORY ON
WEDNESDAY. LINGERING FLURRIES MAY CONTINUE IN THE EAST WEDNESDAY
NIGHT...BEFORE ALL PRECIPITATION MOVES OFF BY EARLY THURSDAY.
ACCUMULATIONS AT THIS TIME APPEAR TO BE LIGHT...THOUGH SOME PLACES
COULD PICK UP AN INCH OR SO THROUGH THE ENTIRE 24-36 HOUR PERIOD OF
LIGHT SNOW SHOWERS FROM MIDDAY TUESDAY THROUGH LATE WEDNESDAY.
QUIET PERIOD THURSDAY THROUGH THE EARLY PART OF THE WEEKEND BEFORE A
BROAD UPPER TROUGH OVER THE WESTERN UNITED STATES RETURNS ACTIVE
SOUTHWEST FLOW ALOFT TO THE REGION BY LATE SUNDAY.
&&
.AVIATION (00Z TAFS)...
EXPECT LOW CLOUDS TO CONTINUE OVER MUCH OF CENTRAL KENTUCKY AND
SOUTH CENTRAL INDIANA OVERNIGHT WITH CIGS 1-2 THSD FEET AT SDF AND
LEX AND A LITTLE HIGHER AT BWG. BOTH MODEL TIME SECTIONS AND
AIRCRAFT SOUNDINGS INDICATE DEEP MOISTURE WAS OVER THE AREA BETWEEN
18Z AND 00Z. TIME SECTIONS SHOW ATMOSPHERE DRYING OUT IN THE MID AND
UPPER LEVELS OVERNIGHT BUT THE MOISTURE REMAINS HIGH IN THE LOWER
LEVELS. THUS WILL KEEP CIGS BELOW 2 THSD FT THROUGH MID MORNING
ACROSS THE NORTH WITH HIGHER CIGS AT BWG.
DURING THE DAY MONDAY...WINDS WILL BECOME MORE SOUTHERLY WITH TIME
SECTIONS INDICATED LOWER LEVEL OF ATMOSPHERE WILL CONTINUE TO DRY.
AS A RESULT LOWER CLOUDS WILL BEGIN TO LIFT AND MAY BECOME SCATTERED
IN THE AFTERNOON. HOWEVER BY THEN HIGHER CLOUDS AHEAD OF NEXT LOW
PRESSURE AREA WILL SPREAD OVER THE REGION.
THE PRECIPITATION FROM DURING THE DAY HAS MOVED TO THE EAST AND
SHOWERS FROM THE NEXT SYSTEM WILL HOLD OFF UNTIL AFTER 00Z.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...NONE.
IN...NONE.
&&
$$
SHORT TERM...DK
LONG TERM....MACZKO
AVIATION.....SCHOLZ
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
407 PM EST SUN FEB 24 2008
LATEST UPDATE...SHORT TERM
.SYNOPSIS...(407 PM EST SUN FEB 24 2008)
A LOW PRESSURE SYSTEM IS FORECAST TO SWING OUT OF THE PLAINS ON
MONDAY AND MOVE ACROSS CENTRAL ILLINOIS AND INDIANA MONDAY NIGHT AND
TUESDAY. THE TRACK OF THE LOW WILL SUPPORT HEAVY SNOW ACROSS
SOUTHERN LOWER MICHIGAN. THE SNOW SHOULD BREAK OUT IN SOUTHWEST
LOWER MICHIGAN MONDAY AFTERNOON...PERSISTING THROUGH THE NIGHT AND
INTO THE DAY ON TUESDAY. IN EXCESS OF 6 INCHES OF SNOW APPEARS
LIKELY FOR PLACE ALONG AND SOUTH OF THE INTERSTATE 96 CORRIDOR. THE
HIGHEST PROBABILITY OF SEEING HEAVY SNOW WILL EXIST FROM SOUTH HAVEN
EAST TO JACKSON. COLDER AIR WILL THEN FILTER INTO THE AREA BEHIND
THIS LOW FOR MID WEEK.
&&
.SHORT TERM...(407 PM EST SUN FEB 24 2008)
(TONIGHT THROUGH TUESDAY)
HAVE OPTED TO ISSUE A WINTER STORM WATCH FOR THE SOUTHERN THREE
TIERS OF COUNTIES IN THE FORECAST ARA. ROUGHLY THE INTERSTATE 96
CORRIDOR SOUTHWARD. COORDINATED WITH IWX AND DTX. EXPECT SNOW TO
BREAK OUT IN FAR SOUTHWEST PORTION OF THE CWA IN THE LATE AFTERNOON
TOWARD EVENING. IT MAY ACTUALLY MIX WITH SOME RAIN AS WELL IN THE
SOUTH TOMORROW EVENING. EXPECT THE SNOW TO BECOME HEAVY MONDAY NIGHT
INTO TUESDAY AS THE SURFACE LOW SLIDES ACROSS CENTRAL INDIANA. THE
TRACK OF THE LOW HAS REMAINED FAIRLY CONSISTENT THE LAST COUPLE
RUNS OF THE GFS AND THE NAM ACROSS CENTRAL INDIANA. LIFT WILL COME
FROM A COMBINATION OF LEFT EXIT REGION DYNAMICS AS WELL AS
FRONTOGENESIS AND ISENTROPIC LIFT. MORE RELIABLE GFS THIS WINTER IS
ACTUALLY KICKING OUT SNOWFALL TOTALS OF AROUND A FOOT ALONG THE I94
CORRIDOR. THINK THE SPEED OF THE SYSTEM WILL KEEP AMOUNTS UNDER THAT
HOWEVER AND WILL BE MENTIONING THE POTENTIAL FOR IN EXCESS OF 6
INCHES IN THE WSW. IN GENERAL THINKING 5 TO 8 POSSIBLE IN THE WATCH.
WILL BE FINE TUNING THINGS OVER THE COURSE OF THE NEXT 12 TO 18
HOURS AS THE SYSTEM MOVES OUT OF THE ROCKIES. CONFIDENCE IS HIGH
ENOUGH TO GO WITH A WATCH AT THIS POINT. LATER MODEL RUNS WILL NAIL
DOWN WHERE FUTURE HEADLINE MAY BE NEEDED.
SHOULD BE A FAIRLY QUIET NIGHT TONIGHT. WILL NEED TO KEEP AN EYE ON
THE POTENTIAL FOR LOW CLOUDS TONIGHT ALONG WITH FOG AND DRIZZLE. DID
NOT INCLUDE IT IN THE ZONES AT THIS POINT.
&&
.LONG TERM...(407 PM EST SUN FEB 24 2008)
(TUESDAY NIGHT THROUGH SATURDAY)
THE SYSTEM WILL EXIT TOWARD NEW ENGLAND TUESDAY NIGHT. SOME LIGHT
SNOW MAY LINGER INTO THE EVENING IN THE EAST...SO WILL MAINTAIN
CHANCE POPS THERE. A SURGE OF ARCTIC AIR WILL ARRIVE OVERNIGHT WITH
H8 TEMPS APPROACHING -20C. WITH THE CYCLONIC FLOW BEHIND THE SYSTEM
LAKE EFFECT SNOW WILL KICK IN OVERNIGHT INTO WEDNESDAY...ESPECIALLY
IN THE WEST. THEN...RIDGING WORKS INTO THE GREAT LAKES THROUGH
WEDNESDAY NIGHT WHICH SHOULD HELP DWINDLE THE LAKE SNOW.
ANY BREAK IN THE SNOW APPEARS TO BE BRIEF AS WE BEGIN TO WARM ADVECT
LATE IN THE DAY ON THURSDAY AHEAD OF A CLIPPER SYSTEM. ALTHOUGH
THIS WILL BRING TEMPS UP ABOUT 5 DEGREES IT WILL ALSO BRING THE
CHANCE OF SNOW BACK INTO THE REGION LATE IN THE DAY. THE CLIPPER
PASSES OVER THE AREA THURSDAY NIGHT INTO FRIDAY. IT APPEARS A
SECONDARY FRONT COMES THROUGH FRIDAY NIGHT AND ALONG WITH ANOTHER
POCKET OF COLD AIR LAKE ENHANCED SNOW COULD LINGER INTO SATURDAY.
WILL KEEP SATURDAY NIGHT AND SUNDAY DRY AS A SURFACE RIDGE MOVES IN.
&&
.AVIATION...(645 AM EST SUN FEB 24 2008)
WIDESPREAD MVFR FOG DEVELOPED OVERNIGHT. TAMDAR DATA SHOWS AN
INVERSION AROUND THE REGION. LOOKS LIKE THIS INVERSION WILL KEEP
THE FOG TRAPPED FOR AT LEAST A FEW HOURS THIS AM. I FEATURED AN
IMPROVEMENT BY 15Z. THEN CONDITIONS ARE TO REMAIN VFR UNTIL
TONIGHT...WHEN THE AREA OF LOW CLOUDS IN MN TRACKS EASTWARD TO AT
LEAST KGRR AND KBTL. ALLOWED FOR SOME IFR LEVELS...MAINLY AFTER 09Z.
&&
.MARINE...(407 PM EST SUN FEB 24 2008)
RATHER QUIET CONDITIONS ARE EXPECTED OUT ON LAKE MICHIGAN TONIGHT
INTO MONDAY. WINDS WILL INCREASE OUT OF THE NORTHEAST AND NORTH
MONDAY NIGHT INTO TUESDAY AS A DEEPENING AREA OF LOW PRESSURE SWINGS
BY TO THE SOUTH OF LAKE MICHIGAN. WAVES WILL BE ON THE INCREASE
MONDAY NIGHT AND ESPECIALLY INTO TUESDAY. SMALL CRAFT ADVISORIES
WILL BE NEEDED.
&&
.HYDROLOGY...(407 PM EST SUN FEB 24 2008)
RIVERS CONTINUE TO FALL ACROSS THE AREA. THE FLOOD WARNING CONTINUES
AT COMSTOCK PARK WITH THE LEVEL FALLING THERE AS WELL. THE STAGE AT
130 PM WAS 12.6 FEET. FLOOD STAGE IS 12.0 FEET. THE FALL MAY BE
SLOWED BY THE SNOW TOMORROW NIGHT AND TUESDAY AND THE RETURN TO
COLDER TEMPERATURES BEHIND THE STORM SYSTEM.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS: DUKE
SHORT TERM: DUKE
LONG TERM: JK
AVIATION: MJS
MARINE: DUKE
HYDROLOGY: DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1146 AM EST SUN FEB 24 2008
LATEST UPDATE...SHORT TERM
.SYNOPSIS...(408 AM EST SUN FEB 24 2008)
HIGH PRESSURE CENTERED JUST SOUTH OF THE STATE THIS MORNING WILL
SLOWLY SLIDE SOUTHEAST AWAY FROM THE AREA THROUGH THE DAY ON MONDAY.
SOUTHWESTERLY WINDS WILL HELP TO GRADUALLY BRING MILDER TEMPERATURES
TO THE AREA TODAY AND DURING THE DAY ON MONDAY. A GOOD DEAL OF
SUNSHINE IS EXPECTED TODAY IN MOST AREAS...THE EXCEPTION WILL BE
FROM SOUTH HAVEN NORTHEAST THROUGH GRAND RAPIDS WHERE SOME LAKE
CLOUDS ARE WORKING THROUGH. CLOUDS WILL BE ON THE INCREASE TONIGHT
OUT AHEAD OF AN INCOMING STORM SYSTEM. THIS STORM SYSTEM IS
EXPECTED TO SPREAD SNOW ACROSS THE AREA LATE MONDAY AFTERNOON AND
MONDAY NIGHT. SNOW WILL LINGER INTO THE FIRST PART OF TUESDAY BEFORE
DIMINISHING. ACCUMULATING SNOWS LOOK LIKELY...ESPECIALLY FOR AREAS
ALONG AND SOUTH OF INTERSTATE 96.
&&
.SHORT TERM...(1146 AM EST SUN FEB 24 2008)
GOING FORECAST LOOKS FINE...JUST TWEAKED THE CLOUDS A BIT TO GO WITH
MORE OF A PARTLY SUNNY FORECAST FROM SOUTH HAVEN TO GRAND RAPIDS.
STREAMER OF LAKE CLOUDS POURING OFF LAKE MICHIGAN...MUCH LIKE
YESTERDAY IN SOUTHWEST FLOW. AS MIXING CONTINUES THIS AFTERNOON AND
SURFACE TEMPS CONTINUE TO WARM UPSTREAM OF THE LAKE...EXPECT THESE
CLOUDS TO SCATTER OUT SLOWLY.
FOCUS DURING THE AFTERNOON WILL BE ON THE APPROACHING STORM SYSTEM
FOR MONDAY AFTERNOON THROUGH TUESDAY MORNING. NAM TRENDED DOWN IN
ITS SNOWFALL TOTALS. WILL BE LOOKING INTO DETAILS OF THE SYSTEM IN
THE EARLY AFTERNOON. BOTH THE NAM AND GFS TAKE THE LOW ON A FAIRLY
SOUTHERN TRACK FOR OUR CWA...ACROSS CENTRAL INDIANA. TREND IN BOTH
MODELS WAS SLIGHTLY TO THE SOUTH OF ITS PREVIOUS RUN (06Z). MORE TO
FOLLOW ON THIS SYSTEM WITH THE AFTERNOON FORECAST PACKAGE.
&&
.LONG TERM...(408 AM EST SUN FEB 24 2008)
(TUESDAY NIGHT THROUGH SATURDAY)
THE MAIN CHALLENGE OVER THE LONG TERM DEALS WITH THE POTENTIAL
PRECIPITATION EVENT FOR THU NIGHT INTO FRI. A MID LEVEL WAVE WILL
BE DROPPING SOUTHEASTWARD THROUGH THE CANADIAN PRAIRIES ON
THURSDAY. A ZONE OF STRONG WARM AIR ADVECTION WILL BE DEVELOPING
AHEAD OF THIS SYSTEM...LEADING TO CLOUDS AND SOME PRECIPITATION INTO
THE UPPER PLAINS LATER THURSDAY...THAT WILL SPREAD INTO THE GREAT
LAKES REGION THURSDAY NIGHT. SOUTHWEST LOWER MI WILL BE ON THE
SOUTHERN EDGE OF THE STEADIER PRECIPITATION...SO WILL NOT RAISE
POPS AT THIS TIME. I WILL STILL FAVOR SNOW AS THE PRECIPITATION
TYPE...BUT WARMER AIR WILL LIKELY BE TRYING TO MOVE INTO THE
REGION. THE GFS SOUNDINGS SUPPORT SNOW WITH THIS SYSTEM...PERHAPS
SOME HEAVIER SNOW. THE ECMWF AND CANADIAN GEM ARE WARMER AND FURTHER
NORTH WITH THE BEST SATURATION AND LOW TRACK. I LOWERED POPS
THU...AS THE SYSTEM LOOKS TO BE COMING IN LATER FROM MOST MODELS.
THERE WILL BE SOME LAKE EFFECT SNOW SHOWERS ON THE BACKSIDE OF THE
DEPARTING STORM TUE NIGHT INTO WED. INVERSION HEIGHTS ARE UP TO
800 MB...SUGGESTING LIMITED MOISTURE DEPTH. WILL HOLD ONTO THE CHC
POPS AT THIS TIME.
&&
.AVIATION...(645 AM EST SUN FEB 24 2008)
WIDESPREAD MVFR FOG DEVELOPED OVERNIGHT. TAMDAR DATA SHOWS AN
INVERSION AROUND THE REGION. LOOKS LIKE THIS INVERSION WILL KEEP
THE FOG TRAPPED FOR AT LEAST A FEW HOURS THIS AM. I FEATURED AN
IMPROVEMENT BY 15Z. THEN CONDITIONS ARE TO REMAIN VFR UNTIL
TONIGHT...WHEN THE AREA OF LOW CLOUDS IN MN TRACKS EASTWARD TO AT
LEAST KGRR AND KBTL. ALLOWED FOR SOME IFR LEVELS...MAINLY AFTER 09Z.
&&
.MARINE...(408 AM EST SUN FEB 24 2008)
SOUTHWEST WINDS ARE RELATIVELY LIGHT ACROSS THE NEARSHORE WATERS
THIS MORNING. WINDS WILL LIKELY PICK UP INTO THE 10 TO 20 KNOTS
RANGE TODAY AS RETURN FLOW ON THE BACKSIDE OF THE HIGH MOVES
OVERHEAD. THESE WINDS WILL CONTINUE INTO THE OVERNIGHT PERIOD BEFORE
DIMINISHING AS A WEAKER PRESSURE GRADIENT MOVES IN. ADVISORY
CRITERIA LOOKS JUST OUT OF REACH THROUGH THE TIME PERIOD. WINDS WILL
PICK UP LATE MON NIGHT INTO TUE AS STORM SYSTEM INTENSIFIES TO OUR
SOUTHEAST AND COLD AIR RUSHES BACK INTO THE AREA. THIS IS WHEN NEXT
SET OF HEADLINES MAY BE NEEDED.
&&
.HYDROLOGY...(408 AM EST SUN FEB 24 2008)
MOST AREA RIVERS ARE NOW HOLDING STEADY OR FALLING. COMSTOCK PARK
HAS STARTED TO SLOWLY FALL WITH THE LAST READING AT 12.8 FEET. NO
PRECIPITATION AND SLIGHTLY WARMER DAY TIME HIGHS FOR TODAY AND
MONDAY WILL LIKELY CONTINUE THE TREND OF FALLING RIVER LEVELS.
COLDER WEATHER RETURNING FOR MID WEEK THOUGH SHOULD BRING AN
INCREASE TO ICE IN THE RIVERS ONCE AGAIN. THE SYSTEM FOR MONDAY AND
TUESDAY SHOULD MAINLY BE SNOW...SO NO MAJOR RUNOFF EXPECTED INTO THE
RIVERS THROUGH MOST OF THE UPCOMING WEEK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS: NJJ
SHORT TERM: DUKE
LONG TERM: MJS
AVIATION: MJS
MARINE: NJJ
HYDROLOGY: NJJ
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
948 PM CST SUN FEB 24 2008
.JUST UPDATED THE ZONE PACKAGE MAINLY FOR PRECIPITATION TYPE AND TO
INCREASE TEMPERATURES OVERNIGHT. IMPRESSIVE WARM AIR ADVECTION
UNDERWAY TO THE SOUTH AND SOUTHWEST OF THE CWA THIS EVENING. THIS
ADVECTION WILL MOVE NORTH AND NORTHEAST OVERNIGHT INTO WESTERN AND
NORTH CENTRAL NEBRASKA. BOOSTED TEMPS ACCORDINGLY DUE TO THIS FACT
AND INCREASED CLOUD COVER STREAMING FROM THE SOUTHWEST. WITH WARMER
TEMPS EXPECTED OVERNIGHT TRIMMED BACK SNOW MENTION TO THE NWRN ZONES
AS SFC WET BULB TEMPS TO WARM FOR SNOW FURTHER EAST AND SOUTH. AS
FOR HEADLINES TOMORROW...FEEL SNOW THREAT TOO LIMITED FOR A WINTER
WX ADVISORY IN THE NORTHEASTERN ZONES ATTM. AS FOR WIND ADVISORY
POTENTIAL ON MONDAY...THOUGHTS AT THIS JUNCTURE ARE FOR THE FAR
SOUTHWESTERN ZONES...WHERE LIMITED CLOUD COVER MONDAY AFTERNOON WILL
ENHANCE MIXING POTENTIAL.
&&
PREVIOUS DISCUSSION FOLLOWS...
ISSUED AT 347 PM CST SUN FEB 24 2008
.SYNOPSIS...
LARGE LOW PRESSURE SYSTEM QUICKLY MOVING ACROSS THE WESTERN CONUS
THIS AFTERNOON. MEANWHILE SURFACE COLD FRONT MOVING SOUTH OUT OF
CANADA. ACROSS WESTERN NEBRASKA...HIGH CLOUDS SPREADING AHEAD OF
WESTERN SYSTEM HAS NOT HAMPERED TEMPS FROM REACHING INTO THE UPPER
50S AND EVEN A FEW LOW 60S THIS AFTERNOON.
&&
.DISCUSSION...
COMPLEX FORECAST TONIGHT AS WESTERN SYSTEM MOVES ACROSS THE
PLAINS AND MERGES WITH COLD AIR FROM THE NORTH. MODELS NOT
HANDLING THE SYSTEM VERY WELL...AND HAVE SIDED CLOSER TO THE
GFS/SREF SOLUTION...WHICH HAVE BEEN MOST CONSISTENT THE PAST
SEVERAL RUNS. TEMP PROFILE WELL ABOVE FREEZING INITIALLY
TONIGHT...SO PRECIP TYPE WILL BE RAIN. ALTHOUGH SURFACE FAIRLY DRY
AND WILL HAVE TO SATURATE TOP DOWN. THEN COLD AIR ARRIVES FROM
NORTH TO SOUTH AND WILL CHANGE RAIN TO SNOW. Q VECTOR CONVERGENCE
LOCATED ACROSS THE NORTHEASTERN COUNTIES DURING THE EARLY MORNING
HOURS...HOWEVER BEST LIFT...PER MODEL SOUNDING
ANALYSIS...BELOW/WARMER THAN THE FAVORED DENDTRITIC SNOW GROWTH
LAYER. STILL MODELS PRODUCING MODEST QPF WITH SHORT DURATION. WITH
INITIALLY PRECIP TYPE RAIN...TIMING CHANGE OVER TO SNOW GOING TO
BE CRITICAL TO SNOW AMOUNTS. HAVE BLENDED CHANGE OVER WHICH OCCURS
DURING THE EARLY MORNING HOURS OVER THE NE. HIGHEST SNOW AMOUNTS
EXPECTED TO BE UP TO 3 INCHES BEFORE SYSTEM WINDS DOWN TOMORROW
AFTERNOON. ANOTHER CONCERN WILL BE WINDS BEHIND COLD FRONT. 850MB
WINDS RAMP UP TO 40 TO 50KTS BY TOMORROW AFTERNOON ACROSS
SW/CENTRAL NEBRASKA. MOS GUIDANCE SUGGESTS JUST BELOW ADV CRITERIA
AND WILL FOLLOW GUIDANCE FOR NOW. WILL HAVE TO MONITOR AS EXPECTED
CLOUD COVER TO INHIBIT MIXING STRONGEST WINDS TO THE
SURFACE...HOWEVER IF CLOUDS BEGIN TO DISPERSE DURING THE AFTERNOON
AREAS SOUTH OF AN OGA TO BBW MAY BRIEFLY REACH WIND ADVISORY.
SYSTEM QUICKLY EXITS THE REGION WITH HIGH PRESSURE RETURNING TO
THE REGION FOR TUESDAY. NORTHWEST FLOW SETS UP FOR MOST OF THE
WEEK. SEVERAL IMPULSES TO RIDE ACROSS THE REGION...ALTHOUGH
LIMITED MOISTURE TO WORK WITH SO MAINLY A DRY TO SMALL POP
FORECAST WARRANTED. TEMPS ALSO WILL SLOWLY REBOUND AS WARM AIR
BUILDS TO THE WEST. NE ZONES MAY BE COOLED BY EXPECTED SNOW COVER
FOR A FEW DAYS INITIALLY.
THEN BY THE WEEKEND ANOTHER TROF TO DIG ACROSS THE WESTERN CONUS
AND WILL PUSH RIDGE AXIS TOWARDS THE CENTRAL PLAINS. THIS WILL
WARM TEMPS BACK UP ABOVE NORMAL FOR THE WEEKEND.
&&
.AVIATION...
QUICK MOVING SYSTEM WILL EJECT FROM THE ROCKIES OVERNIGHT AND
PROGRESS ACROSS THE PLAINS ON MONDAY. THIS WILL BRING A COLD FRONT
ACROSS NEBRASKA BY SUNRISE WITH NORTHWEST WINDS OF AROUND 25 MPH
WITH HIGHER GUSTS CREATING SOME CONCERN FOR LIGHT AIRCRAFT. A
MIXTURE OF PRECIPITATION WILL BEGIN LATE TONIGHT FOLLOWED BY A
CHANGEOVER TO ALL SNOW BY SUNRISE. CONDITIONS WILL BE VFR THROUGH
THE EARLY MORNING HOURS...BUT BEHIND THE FRONT MVFR TO IFR/LIFR
CONDITIONS CAN BE EXPECTED. THE LOWER CAT CONDITIONS SHOULD MAINLY
BE ACROSS NORTHERN NEBRASKA WHERE CIGS WILL DROP BELOW 1KFT AGL AND
VSBYS REDUCED TO LESS THAN A MILE A TIMES IN THE SNOW SHOWERS.
FARTHER SOUTH...VSBYS SHOULD BE UNLIMITED...BUT CLOUD DECKS LOOK TO
BE IN THE 15 TO 25KFT AGL RANGE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
MASEK/13/CLB
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
347 PM CST SUN FEB 24 2008
.SYNOPSIS...
LARGE LOW PRESSURE SYSTEM QUICKLY MOVING ACROSS THE WESTERN CONUS
THIS AFTERNOON. MEANWHILE SURFACE COLD FRONT MOVING SOUTH OUT OF
CANADA. ACROSS WESTERN NEBRASKA...HIGH CLOUDS SPREADING AHEAD OF
WESTERN SYSTEM HAS NOT HAMPERED TEMPS FROM REACHING INTO THE UPPER
50S AND EVEN A FEW LOW 60S THIS AFTERNOON.
&&
.DISCUSSION...
COMPLEX FORECAST TONIGHT AS WESTERN SYSTEM MOVES ACROSS THE
PLAINS AND MERGES WITH COLD AIR FROM THE NORTH. MODELS NOT
HANDLING THE SYSTEM VERY WELL...AND HAVE SIDED CLOSER TO THE
GFS/SREF SOLUTION...WHICH HAVE BEEN MOST CONSISTENT THE PAST
SEVERAL RUNS. TEMP PROFILE WELL ABOVE FREEZING INITIALLY
TONIGHT...SO PRECIP TYPE WILL BE RAIN. ALTHOUGH SURFACE FAIRLY DRY
AND WILL HAVE TO SATURATE TOP DOWN. THEN COLD AIR ARRIVES FROM
NORTH TO SOUTH AND WILL CHANGE RAIN TO SNOW. Q VECTOR CONVERGENCE
LOCATED ACROSS THE NORTHEASTERN COUNTIES DURING THE EARLY MORNING
HOURS...HOWEVER BEST LIFT...PER MODEL SOUNDING
ANALYSIS...BELOW/WARMER THAN THE FAVORED DENDTRITIC SNOW GROWTH
LAYER. STILL MODELS PRODUCING MODEST QPF WITH SHORT DURATION. WITH
INITIALLY PRECIP TYPE RAIN...TIMING CHANGE OVER TO SNOW GOING TO
BE CRITICAL TO SNOW AMOUNTS. HAVE BLENDED CHANGE OVER WHICH OCCURS
DURING THE EARLY MORNING HOURS OVER THE NE. HIGHEST SNOW AMOUNTS
EXPECTED TO BE UP TO 3 INCHES BEFORE SYSTEM WINDS DOWN TOMORROW
AFTERNOON. ANOTHER CONCERN WILL BE WINDS BEHIND COLD FRONT. 850MB
WINDS RAMP UP TO 40 TO 50KTS BY TOMORROW AFTERNOON ACROSS
SW/CENTRAL NEBRASKA. MOS GUIDANCE SUGGESTS JUST BELOW ADV CRITERIA
AND WILL FOLLOW GUIDANCE FOR NOW. WILL HAVE TO MONITOR AS EXPECTED
CLOUD COVER TO INHIBIT MIXING STRONGEST WINDS TO THE
SURFACE...HOWEVER IF CLOUDS BEGIN TO DISPERSE DURING THE AFTERNOON
AREAS SOUTH OF AN OGA TO BBW MAY BRIEFLY REACH WIND ADVISORY.
SYSTEM QUICKLY EXITS THE REGION WITH HIGH PRESSURE RETURNING TO
THE REGION FOR TUESDAY. NORTHWEST FLOW SETS UP FOR MOST OF THE
WEEK. SEVERAL IMPULSES TO RIDE ACROSS THE REGION...ALTHOUGH
LIMITED MOISTURE TO WORK WITH SO MAINLY A DRY TO SMALL POP
FORECAST WARRANTED. TEMPS ALSO WILL SLOWLY REBOUND AS WARM AIR
BUILDS TO THE WEST. NE ZONES MAY BE COOLED BY EXPECTED SNOW COVER
FOR A FEW DAYS INITIALLY.
THEN BY THE WEEKEND ANOTHER TROF TO DIG ACROSS THE WESTERN CONUS
AND WILL PUSH RIDGE AXIS TOWARDS THE CENTRAL PLAINS. THIS WILL
WARM TEMPS BACK UP ABOVE NORMAL FOR THE WEEKEND.
&&
.AVIATION...
QUICK MOVING SYSTEM WILL EJECT FROM THE ROCKIES OVERNIGHT AND
PROGRESS ACROSS THE PLAINS ON MONDAY. THIS WILL BRING A COLD FRONT
ACROSS NEBRASKA BY SUNRISE WITH NORTHWEST WINDS OF AROUND 25 MPH
WITH HIGHER GUSTS CREATING SOME CONCERN FOR LIGHT AIRCRAFT. A
MIXTURE OF PRECIPITATION WILL BEGIN LATE TONIGHT FOLLOWED BY A
CHANGEOVER TO ALL SNOW BY SUNRISE. CONDITIONS WILL BE VFR THROUGH
THE EARLY MORNING HOURS...BUT BEHIND THE FRONT MVFR TO IFR/LIFR
CONDITIONS CAN BE EXPECTED. THE LOWER CAT CONDITIONS SHOULD MAINLY
BE ACROSS NORTHERN NEBRASKA WHERE CIGS WILL DROP BELOW 1KFT AGL AND
VSBYS REDUCED TO LESS THAN A MILE A TIMES IN THE SNOW SHOWERS.
FARTHER SOUTH...VSBYS SHOULD BE UNLIMITED...BUT CLOUD DECKS LOOK TO
BE IN THE 15 TO 25KFT AGL RANGE.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
MASEK/13
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
917 PM MST SUN FEB 24 2008
.UPDATE...DUE TO A FEW MORE BANDS OF PCPN NOTED ON RADARS ACROSS S
HALF UT AND N AZ...INCLUDING A FEW LIGHTNING STRIKES...DECIDED TO
ADD NW PLATEAU TO THE WINTER WX ADVISORY THROUGH 12Z MON. MAIN
CONCERN FOR NW PLATEAU WILL BE TO NORTH OF HIGHWAY 64. ALSO ADDED
THE REST OF THE EAST CENTRAL AND SE PLAINS TO WIND ADVISORY...
ENDING AT SAME TIME AS THE EXISTING WIND ADVISORY...BUT STARTING
IT AT 15Z.
&&
.PREV DISCUSSION...234 PM MST SUN FEB 24 2008...
21Z SFC ANALYSIS SHOWS A 1006MB LOW PRES CENTER OVER SE CO
EXTENDING SW ACROSS E NM. SFC WINDS ACROSS THE E AND NE ON THE
ORDER OF 25 TO 35 KNOTS WITH A FEW GUSTS NEAR 40 KNOTS. WATER
VAPOR LOOP SHOWS UPPER LOW MOVING ONSHORE NW CA COASTLINE. 400-250
MB AIRCRAFT WIND PLOT SHOWS A 100-130 KNOT JET EXTENDING FROM THE
BASE OF THE TROUGH EAST ACROSS SOUTHERN NV AND NORTHERN AZ. RADAR
SHOWS LIGHT/MODERATE RAIN WITH HIGHER TERRAIN SNOW SPREADING EAST
ACROSS MUCH OF NW CORNER OF NM.
12Z MODELS HANDLING PRECIP FIELD OVER E AZ/W NM POORLY AS OF
18Z. MID AND UPPER LEVEL MOISTURE PLUME FROM SOCA NE TO CENTRAL
PLAINS IS SHOWN TO MOVE WELL NORTH INTO UT/CO AND DISSIPATE
THRU THE EVENING. CHOSE TO FORCE MODEL SOLUTION FARTHER SOUTH
TO CORRECT FOR CURRENT RADAR AND SATELLITE TRENDS. THIS ALIGNS
POPS FROM ALONG AND NORTH OF INTERSTATE 40 FROM THE CENTRAL
MTNS WESTWARD THRU MONDAY MORNING. SHOULD SEE SNOW LEVELS
AROUND 8000 FEET THIS AFTERNOON OVER THE NORTHERN MTNS FALL TO
7000 FEET OVERNIGHT WITH MOIST SW FLOW USHERING IN 3 TO 5 INCHES
OF SNOWFALL ABOVE 7500 FEET. 12Z NAM/GFS BUFKIT PROFILES SHOW
BOUNDARY LAYER DECOUPLING OVERNIGHT ACROSS MOST AREAS THUS
CONFIDENCE IN WIND HIGHLIGHTS THRU THE OVERNIGHT IS LOW. SINCE
WINDS ACROSS E AZ HAVE REMAINED BELOW OUR ADV CRITERIA AND MAX
700MB FLOW SHOULD BE DISPLACED FARTHER SOUTH DECIDED TO CANCEL
WIND ADVISORY FOR ZONES 8 AND 14.
SNOW WILL TAPER OFF OVER THE NORTHERN MTNS MONDAY MORNING AS WINDS
BEGIN TO HOWL AGAIN OVER THE E PLAINS. WINDS THEN SUBSIDE AFTER
SUNSET MONDAY WITH CLEARING SKIES FROM WEST TO EAST. A COLD
FRONTAL PASSAGE OVER THE E PLAINS BEHIND THE DEPARTING WAVE WILL
BRING RETURN TO COOLER TEMPS FOR TUESDAY. QUIET WX PATTER SETS UP
THRU THE REMAINDER OF THE WEEK BEFORE THE NEXT DISTURBANCE
TRANSLATES SE ACROSS NORTHERN OLD MEXICO.
GUYER
.AVIATION...
OCCASIONAL MVFR TO IFR CONDITIONS AND OCCASIONAL MOUNTAIN
OBSCURATIONS ARE FORECAST OVER THE NORTHWEST THIRD OF NEW MEXICO FOR
THE NEXT 12 HOURS. STRONG SOUTHWEST TO WEST WINDS AT MOUNTAINTOP
LEVEL WILL EXTEND APPROXIMATELY FROM INTERSTATE 40 SOUTHWARD AND
FROM THE EAST SLOPES OF THE CENTRAL MOUNTAIN CHAIN TO THE TEXAS
BORDER. LOCAL WESTERLY SURFACE WIND GUSTS OF 35 TO 45 KTS ARE
POSSIBLE.
NEXT AVIATION DISCUSSION SCHEDULED FOR 10Z.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 AM MST MONDAY FOR THE FOLLOWING
ZONES...NMZ001-002-004.
WIND ADVISORY UNTIL 5 PM MST MONDAY FOR THE FOLLOWING ZONES...
NMZ005-010>012-016-017-026.
WIND ADVISORY FROM 8 AM TO 5 PM MST MONDAY FOR THE FOLLOWING
ZONES...NMZ013-018>021.
FIRE WEATHER WATCH FROM MONDAY MORNING THROUGH MONDAY AFTERNOON FOR
THE FOLLOWING ZONES...NMZ108.
&&
$$
43
AREA FORECAST DISCUSSION
NWS ALBUQUERQUE NM
234 PM MST SUN FEB 24 2008
.DISCUSSION...
21Z SFC ANALYSIS SHOWS A 1006MB LOW PRES CENTER OVER SE CO
EXTENDING SW ACROSS E NM. SFC WINDS ACROSS THE E AND NE ON THE
ORDER OF 25 TO 35 KNOTS WITH A FEW GUSTS NEAR 40 KNOTS. WATER
VAPOR LOOP SHOWS UPPER LOW MOVING ONSHORE NW CA COASTLINE. 400-250
MB AIRCRAFT WIND PLOT SHOWS A 100-130 KNOT JET EXTENDING FROM THE
BASE OF THE TROUGH EAST ACROSS SOUTHERN NV AND NORTHERN AZ. RADAR
SHOWS LIGHT/MODERATE RAIN WITH HIGHER TERRAIN SNOW SPREADING EAST
ACROSS MUCH OF NW CORNER OF NM.
12Z MODELS HANDLING PRECIP FIELD OVER E AZ/W NM POORLY AS OF
18Z. MID AND UPPER LEVEL MOISTURE PLUME FROM SOCA NE TO CENTRAL
PLAINS IS SHOWN TO MOVE WELL NORTH INTO UT/CO AND DISSIPATE
THRU THE EVENING. CHOSE TO FORCE MODEL SOLUTION FARTHER SOUTH
TO CORRECT FOR CURRENT RADAR AND SATELLITE TRENDS. THIS ALIGNS
POPS FROM ALONG AND NORTH OF INTERSTATE 40 FROM THE CENTRAL
MTNS WESTWARD THRU MONDAY MORNING. SHOULD SEE SNOW LEVELS
AROUND 8000 FEET THIS AFTERNOON OVER THE NORTHERN MTNS FALL TO
7000 FEET OVERNIGHT WITH MOIST SW FLOW USHERING IN 3 TO 5 INCHES
OF SNOWFALL ABOVE 7500 FEET. 12Z NAM/GFS BUFKIT PROFILES SHOW
BOUNDARY LAYER DECOUPLING OVERNIGHT ACROSS MOST AREAS THUS
CONFIDENCE IN WIND HIGHLIGHTS THRU THE OVERNIGHT IS LOW. SINCE
WINDS ACROSS E AZ HAVE REMAINED BELOW OUR ADV CRITERIA AND MAX
700MB FLOW SHOULD BE DISPLACED FARTHER SOUTH DECIDED TO CANCEL
WIND ADVISORY FOR ZONES 8 AND 14.
SNOW WILL TAPER OFF OVER THE NORTHERN MTNS MONDAY MORNING AS WINDS
BEGIN TO HOWL AGAIN OVER THE E PLAINS. WINDS THEN SUBSIDE AFTER
SUNSET MONDAY WITH CLEARING SKIES FROM WEST TO EAST. A COLD
FRONTAL PASSAGE OVER THE E PLAINS BEHIND THE DEPARTING WAVE WILL
BRING RETURN TO COOLER TEMPS FOR TUESDAY. QUIET WX PATTER SETS UP
THRU THE REMAINDER OF THE WEEK BEFORE THE NEXT DISTURBANCE
TRANSLATES SE ACROSS NORTHERN OLD MEXICO.
GUYER
&&
.AVIATION...
OCCASIONAL MVFR TO IFR CONDITIONS AND OCCASIONAL MOUNTAIN
OBSCURATIONS ARE FORECAST OVER THE NORTHWEST THIRD OF NEW MEXICO FOR
THE NEXT 12 HOURS. STRONG SOUTHWEST TO WEST WINDS AT MOUNTAINTOP
LEVEL WILL EXTEND APPROXIMATELY FROM INTERSTATE 40 SOUTHWARD AND
FROM THE EAST SLOPES OF THE CENTRAL MOUNTAIN CHAIN TO THE TEXAS
BORDER. LOCAL WESTERLY SURFACE WIND GUSTS OF 35 TO 45 KTS ARE
POSSIBLE.
NEXT AVIATION DISCUSSION SCHEDULED FOR 10Z.
&&
.PRELIMINARY POINT TEMPS/POPS...
FARMINGTON...................... 32 49 24 50 / 50 10 10 0
GALLUP.......................... 30 47 18 52 / 50 10 0 0
GRANTS.......................... 28 48 17 51 / 40 10 0 0
GLENWOOD........................ 32 63 27 67 / 5 0 0 0
CHAMA........................... 22 42 12 44 / 60 40 20 5
LOS ALAMOS...................... 30 44 21 45 / 50 20 0 5
RED RIVER....................... 26 36 13 37 / 50 40 20 10
TAOS............................ 28 44 13 46 / 40 30 10 5
SANTA FE........................ 30 46 22 47 / 50 30 0 5
SANTA FE AIRPORT................ 32 49 22 50 / 40 20 0 5
ESPANOLA........................ 32 53 21 53 / 30 20 0 5
ALBUQUERQUE HEIGHTS............. 36 55 30 56 / 10 5 0 0
ALBUQUERQUE VALLEY.............. 36 57 27 58 / 10 0 0 0
ALBUQUERQUE FOOTHILLS........... 35 52 28 54 / 20 10 0 0
ALBUQUERQUE WEST MESA........... 35 55 29 56 / 20 5 0 0
SOCORRO......................... 37 64 29 62 / 0 0 0 0
SANDIA PARK/CEDAR CREST......... 30 43 20 49 / 40 20 0 0
MORIARTY/ESTANCIA............... 37 52 24 53 / 10 10 0 0
CARRIZOZO....................... 44 62 30 61 / 0 0 0 0
RUIDOSO......................... 39 56 27 52 / 0 0 0 0
RATON........................... 28 52 21 48 / 10 10 10 20
LAS VEGAS....................... 32 50 19 45 / 10 5 0 10
ROY............................. 33 54 23 49 / 5 5 0 10
CLAYTON......................... 34 56 25 50 / 0 5 10 10
SANTA ROSA...................... 42 62 30 55 / 0 0 0 5
TUCUMCARI....................... 40 63 28 56 / 0 0 0 10
FORT SUMNER..................... 42 64 31 57 / 0 0 0 5
CLOVIS.......................... 40 64 30 54 / 0 0 0 5
PORTALES........................ 40 66 29 56 / 0 0 0 5
ROSWELL......................... 43 74 35 62 / 0 0 0 0
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 AM MST MONDAY FOR THE FOLLOWING
ZONES...NMZ002-004.
WIND ADVISORY UNTIL 10 AM MST MONDAY FOR THE FOLLOWING ZONES...
NMZ005-010>012-016-017-026.
FIRE WEATHER WATCH FROM MONDAY MORNING THROUGH MONDAY AFTERNOON FOR
THE FOLLOWING ZONES...NMZ108.
&&
$$
GUYER/99
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1005 AM EST SAT FEB 23 2008
.SYNOPSIS...
WEAK LOW PRESSURE WILL LINGER OVER CENTRAL AND EASTERN NORTH
CAROLINA BEFORE MOVING EAST THIS AFTERNOON. A COLD FRONT WILL MOVE
SOUTH THROUGH THE AREA THIS EVENING... AND THEN A WEAK HIGH PRESSURE
AREAS WILL BUILD OVERHEAD LATE TONIGHT THROUGH SUNDAY. AN UPPER
LEVEL DISTURBANCE WILL ZIP QUICKLY OVERHEAD SUNDAY AFTERNOON.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 AM SATURDAY... THE DENSE FOG ADVISORY HAS BEEN ALLOWED TO
EXPIRE.
AS OF 905 AM SATURDAY... SCATTERED THUNDERSTORMS PERSIST OVER THE
NORTHERN PIEDMONT AND COASTAL PLAIN... ALONG A WEAK SURFACE LOW
PRESSURE TROUGH. NAM BUFR SOUNDINGS AND THE SPC MESOANALYSIS PAGE
INDICATE ELEVATED INSTABILITY ABOVE 900 MB WITH MID LEVEL LAPSE
RATES OVER 7.0 C/KM PUSHING IN FROM THE WEST ASSOCIATED WITH A COLD
FRONT ALOFT. UPPER LEVEL POSITIVE POTENTIAL VORTICITY ADVECTION AND
RIGHT ENTRANCE REGION DYNAMICS WITH THE 130+ KT UPPER JET TO OUR N
ARE LIKELY ALSO CONTRIBUTING TO FORCING FOR ASCENT SUPPORTING THIS
CONVECTION. HAVE EXTENDED THE RISK OF SHOWERS AND THUNDERSTORMS FOR
ANOTHER COUPLE OF HOURS... UNTIL THESE FORCING FEATURES EXIT TO THE
NORTHEAST.
BASED ON THE FACT THAT THE LOW LEVEL SATURATED DECK IS NEARLY A HALF
KM DEEP AND THE LOW LEVEL WIND FIELD SHOULD REMAIN WEAK THROUGH
EARLY AFTERNOON AT LEAST... THESE CLOUDS SHOULD BE TOUGH TO DISLODGE
WITH ANY SWIFTNESS. HAVE SLOWED THE SKY CLEARING BY SEVERAL HOURS.
HAVE ALSO DROPPED HIGHS TODAY BY A FEW DEGREES... TO 56-62... AND
EVEN THESE MAY BE TOO HIGH ESPECIALLY IN THE NE CWA. -GIH
PREVIOUS DISCUSSION FOLLOWS...
THE BACK EDGE OF THE MID AND HIGH LEVEL MOISTURE WAS MOVING EAST
OVER THE PIEDMONT. THIS MAY AID IN THE FOG BECOMING MORE DENSE
THROUGH DAYBREAK OVER THE WESTERN AND SOUTHERN PIEDMONT... AND
POSSIBLY THE SANDHILLS. THEREFORE... WE WILL ISSUE A DENSE FOG
ADVISORY FOR AREAS ALONG AND WEST GREENSBORO TO FAYETTEVILLE
THROUGH 1000 AM.
AS OF 245 AM SATURDAY... THE CURRENT HYBRID COLD AIR DAMMING EPISODE
IS EXPECTED TO LINGER WELL INTO THE LATE MORNING HOURS. THE
LINGERING LOW STATUS AND FOG WILL BE VERY SLOW TO SCOUR OUT THIS
MORNING AS MODELS INDICATE LIGHT WINDS IN THE BOUNDARY LAYER INTO
THE LATE MORNING. CURRENT SURFACE OBS INDICTED CEILINGS AND
VISIBILITIES WERE REMAINING STATUS QUO... EXCEPT FOR LOWERING SOME
OVER DAVIDSON... RANDOLPH... AND STANLY COUNTIES... WHERE WIDESPREAD
VSBYS OF 1/2 TO 1 MILE WERE OBSERVED. WE WILL MONITOR THESE AREAS
CLOSELY. HOWEVER... THE VISIBILITIES ARE EXPECTED TO REMAIN JUST
ABOVE THE THRESHOLD FOR A DENSE FOG ADVISORY.
THE 00Z/NAM WAS THE QUICKEST IN BEGINNING THE CLEARING IN THE LEE OF
THE APPALACHIANS BY MID TO LATE MORNING... WITH THE GFS INDICATING
THE CLEARING WILL BEGIN 3-4 HOURS LATER. GIVEN THE 00Z MODELS LACK
OF ABILITY TO INITIALIZE THE SATURATED BOUNDARY LAYER OVER THE
PIEDMONT DAMMING REGION...AND THE STRENGTH/DEPTH OF THE CAD (3-5K
FEET) BASED ON GSO/RNK 00Z/23 SOUNDINGS... IT APPEARS REASONABLE TO
FAVOR THE SLOWER CLEARING INDICATED BY THE 00Z/GFS. THIS CLEARING
SHOULD GET GOING IN THE LEE OF THE BLUE RIDGE LATE MORNING AS THE
DRY WESTERLY FLOW INCREASES ALOFT WITH THE PASSAGE OF THE MID LEVEL
TROUGH. AS THIS TROUGH MOVES EAST THROUGH CENTRAL NC DURING THE
AFTERNOON... THE CLEARING WILL SPREAD EAST. THERE SHOULD CONTINUE TO
BE SCATTERED TO BROKEN STRATOCUMULUS AT 4-5K FEET EVEN AFTER THE
LOWER STRATUS CLEARS OUT. THUS... WE WILL CONTINUE THE CURRENT
CLOUDY FORECAST THIS MORNING... BECOMING PARTLY CLOUDY THIS
AFTERNOON. THE TEMPERATURES WILL BE HIGHLY DEPENDENT ON HOW MUCH SUN
DEVELOPS THIS AFTERNOON. THE PREVIOUS FORECAST (WHICH LOWERED HIGHS
FOR TODAY) APPEARS VERY REASONABLE. WE WILL CONTINUE THE CURRENT MAX
T FORECASTS INDICATING MID 50S NORTH CENTRAL TO LOWER 60S SE-S.-PWB
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 245 AM SATURDAY...IN THE WAKE OF THE COLD FRONTAL PASSAGE
THIS EVENING... THE SKIES WILL TEMPORARILY BECOME MOSTLY CLEAR
FOR MOST AREAS. THIS WILL BE FOLLOWED BY ANOTHER BOUT OF
STRATUS/STRATOCUMULUS LATER TONIGHT INTO SUNDAY. THIS WILL OCCUR
AS THE LOW LEVEL NE FLOW PULLS ATLANTIC MOISTURE BACK ACROSS OUR
REGION. WHILE MODELS WERE GENERALLY IN AGREEMENT THAT STRATOCUMULUS
WILL EVENTUALLY DEVELOP INTO OUR REGION... THE 00Z/GFS WAS MUCH
FASTER IN SATURATION THE LOW LEVELS ESPECIALLY IN THE EAST
OVERNIGHT... SPREADING WEST BY DAYBREAK. MOSTLY CLEAR OR PARTLY
CLOUDY SKIES EARLY TONIGHT WILL BECOME OVERCAST AGAIN OVERNIGHT.
WITH THIS INCREASINGLY CLOUDY PATTERN TONIGHT... THE WARMER MET
STATISTICAL GUIDANCE WAS PREFERRED OVER THE GFS MOS. LOWS SHOULD
REMAIN IN THE UPPER 30S TO LOWER 40S... INSTEAD OF THE COLDER
LOWER 30S FORECAST BY THE GFS MOS IN THE PIEDMONT.
WITH THE UPPER SHORTWAVE EXPECTED TO MOVE EAST ACROSS THE STATE
DURING THE DAY SUNDAY... THE LIFT AND ASSOCIATED CLOUDINESS ALOFT
WILL COMBINE WITH THE LOW LEVEL MOIST NE FLOW TO KEEP THE
TEMPERATURES ON THE CHILLY SIDE. MAX T`S SUNDAY SHOULD ONLY REACH
THE MID 40S NORTH TO MID 50S SOUTH. THIS UPPER SYSTEM WILL BE
MOISTURE STARVED WITH LITTLE TO NO GULF INFLOW... EXPECT ONLY A
CHANCE OF A FEW SPRINKLES. WE WILL ADVERTISE ONLY A SLIGHT CHANCE
POP FOR ANYTHING THAT MEASURES 0.01. OTHERWISE... ONLY A FEW TRACE
AMOUNTS ARE EXPECTED.
THE UPPER LEVEL DISTURBANCE IS FORECAST TO SHIFT EAST SUNDAY
EVENING AS WEAK HIGH PRESSURE BUILDS IN FROM THE NORTHEAST.
HOWEVER... THE FLOW AT THE SURFACE IS EXPECTED TO REMAIN WEAK...
INDICATING THAT THERE SHOULD STILL BE SOME RESIDUAL LOW LEVEL
MOISTURE AND CLOUDINESS TO DEAL WITH. WE WILL ADVERTISE SKIES TO
BECOME PARTLY CLOUDY AS SUBSIDENCE BEHIND THE DEPARTING SHORT WAVE
FAVORS CLEARING ALOFT. LOWS SHOULD STILL BE ABOVE CURRENT GUIDANCE
AS THE LOW LEVEL MOISTURE SHOULD REMAIN RELATIVE HIGH. EXPECT
MOSTLY MID TO UPPER 30S.
HEIGHTS ARE FORECAST TO RISE ALOFT MONDAY INTO EARLY TUESDAY
AHEAD OF THE NEXT SHORT WAVE TROUGH. THIS WILL BRING MILD TO WARM
TEMPERATURES BACK. THE TRENDS IN THE PAST FEW RUNS HAVE BEEN TO
SPEED UP THIS TROUGH AND THE ASSOCIATED COLD FRONTAL PASSAGE FOR
OUR REGION (NOW APPEARS TO BE DURING THE DAY TUESDAY). THE MAIN
SURFACE STORM TRACK WITH THIS TROUGH IS EXPECTED TO BE WEST TO
EAST THROUGH THE OHIO VALLEY INTO THE NORTHEAST. THE ONLY SHOT AT
SHOWERS FOR CENTRAL NC WILL BE WITH THE TRAILING COLD FRONT
EXPECTED TUESDAY.
SENSIBLE WEATHER MONDAY LOOKS TO BE DRY AND WARMER WITH HIGHS
RETURNING TO THE 60S. INCREASING CLOUDINESS MONDAY NIGHT WITH A
SLIGHT CHANCE OF SHOWERS TOWARD DAYBREAK (NW ONLY). LOWS WILL BE
MILD WITH THE SW FLOW AND INCREASING CLOUDS (MOSTLY MID TO UPPER
40S).
THE SURFACE COLD FRONT SHOULD MOVE THROUGH CENTRAL NC DURING THE
DAY TUESDAY. THE BEST CHANCE OF SIGNIFICANT SHOWERS WILL BE OVER
THE MOUNTAINS. WITH LIMITED DYNAMICS... AND LITTLE IN THE WAY OF
BOUNDARY LAYER INSTABILITY AS THE FRONT MOVES EAST THROUGH CENTRAL
NC... WE SHOULD ONLY SEE A BAND OF LIGHT SHOWERS. QPF WILL BE
FORECAST AT LESS THAN 0.25 OF AN INCH. HIGHS SHOULD STILL REACH
60-65.
STRONG CAA WILL BLOW ACROSS CENTRAL NC BEHIND THE COLD FRONT LATE
TUESDAY AND TUESDAY NIGHT. THE SKIES WILL CLEAR RATHER ABRUPTLY
AFTER THE FROPA WITH STRONG SUBSIDENCE AND DEEP NW FLOW INDICATED
TUESDAY NIGHT. LOWS WILL BE LOWERED INTO THE 25-30 RANGE PER
LATEST GUIDANCE.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
A TRANSIENT POSITIVE PNA PATTERN WILL DEVELOP MIDWEEK RESULTING IN A
LONGWAVE TROUGH AMPLIFYING OVER THE EASTERN PORTION OF THE COUNTRY.
THIS WILL BRING A RETURN OF BELOW NORMAL TEMPERATURES BY WEDNESDAY
AS CANADIAN HIGH PRESSURE BUILDS INTO THE REGION IN THE WAKE OF THE
PREVIOUS NIGHT`S FRONTAL PASSAGE. HIGHS WEDNESDAY SHOULD ONLY MAKE
IT INTO THE UPPER 40S NORTH TO LOWER 50S SOUTH... AND WILL STRUGGLE
TO MAKE IT OUT OF THE MID AND UPPER 40S ON THURSDAY. LOWS WED/THU
NIGHT WILL DIP INTO THE 20S ACROSS MOST OF THE CWA.
AN ALBERTA CLIPPER LOOKS POISED TO APPROACH FROM THE NORTHWEST ON
FRIDAY... SENDING ANOTHER WEAK FRONT THROUGH THE AREA FRIDAY NIGHT.
AS A WEAK SOUTHWEST FLOW DEVELOPS AHEAD OF THE FRONT... TEMPS ARE
APT TO MODERATE SOME DURING THE DAY ON FRIDAY. HIGHS SHOULD REBOUND
CLOSER TO NORMAL LEVELS IN THE LOW TO MID 50S. NO PRECIP IS EXPECTED
AHEAD OF THIS FRONT GIVEN THE DRY NW FLOW REGIME.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 640 AM SATURDAY... LIFR/IFR CONDITIONS WILL CONTINUE THROUGH
THE EARLY MORNING BENEATH A STRONG INVERSION THAT WILL REMAIN AROUND
2K TO 3K FEET THROUGH MOST OF THE MORNING. ALTHOUGH A BIT TOO HIGH
FOR LLWS...AIRCRAFT SHOULD NOTE THAT WINDS NEAR THE INVERSION WILL
REACH AROUND 35KT FROM THE SOUTHWEST THROUGH 15Z WHILE SFC WINDS
REMAIN LIGHT AND VARIABLE. GRADUAL IMPROVEMENT IN CONDITIONS WILL
TAKE PLACE TODAY WITH VISIBILITIES EXPECTED TO BECOME VFR SATURDAY
AFTERNOON AS THE WESTERLY SURFACE FLOW INCREASES. THE LATEST
GUIDANCE HAS DELAYED THE CLEARING OF MVFR/IFR CEILINGS UNTIL LATE
THIS AFTERNOON. THIS IS EVEN WITH THE MODELS NOT FULLING CAPTURING
THE FULL EXTENT OF LOW LEVEL SATURATION SEEN ON THE 00Z/23 GSO
SOUNDING. THEREFORE...HAVE DELAYED VFR CIGS UNTIL LATE AFTERNOON.
LOW CEILINGS LIKELY WILL RETURN LATE SATURDAY NIGHT IN AMPLE
LOW-LEVEL MOISTURE AND A NORTHEAST SURFACE FLOW THAT DEVELOPS
SATURDAY NIGHT OVER CENTRAL NORTH CAROLINA BEHIND A COLD FRONT.
MAINLY MID-LEVEL CLOUDS AND SPRINKLES OR PATCHY LIGHT RAIN ARE
ANTICIPATED BY SUNDAY AFTERNOON WITH THE PASSAGE OF A MODERATE
MID-LEVEL SHORTWAVE. AFTERWARD...THE NEXT...BEST CHANCE FOR MVFR OR
EVEN IFR CONDITIONS WILL BE TUESDAY ALONG AND AHEAD OF A COLD FRONT
THAT WILL SWEEP ACROSS THE STATE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...BADGETT
LONG TERM...JFB
AVIATION...JFB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
905 AM EST SAT FEB 23 2008
.SYNOPSIS...
WEAK LOW PRESSURE WILL LINGER OVER CENTRAL AND EASTERN NORTH
CAROLINA BEFORE MOVING EAST THIS AFTERNOON. A COLD FRONT WILL MOVE
SOUTH THROUGH THE AREA THIS EVENING... AND THEN A WEAK HIGH PRESSURE
AREAS WILL BUILD OVERHEAD LATE TONIGHT THROUGH SUNDAY. AN UPPER
LEVEL DISTURBANCE WILL ZIP QUICKLY OVERHEAD SUNDAY AFTERNOON.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 905 AM SATURDAY... SCATTERED THUNDERSTORMS PERSIST OVER THE
NORTHERN PIEDMONT AND COASTAL PLAIN... ALONG A WEAK SURFACE LOW
PRESSURE TROUGH. NAM BUFR SOUNDINGS AND THE SPC MESOANALYSIS PAGE
INDICATE ELEVATED INSTABILITY ABOVE 900 MB WITH MID LEVEL LAPSE
RATES OVER 7.0 C/KM PUSHING IN FROM THE WEST ASSOCIATED WITH A COLD
FRONT ALOFT. UPPER LEVEL POSITIVE POTENTIAL VORTICITY ADVECTION AND
RIGHT ENTRANCE REGION DYNAMICS WITH THE 130+ KT UPPER JET TO OUR N
ARE LIKELY ALSO CONTRIBUTING TO FORCING FOR ASCENT SUPPORTING THIS
CONVECTION. HAVE EXTENDED THE RISK OF SHOWERS AND THUNDERSTORMS FOR
ANOTHER COUPLE OF HOURS... UNTIL THESE FORCING FEATURES EXIT TO THE
NORTHEAST.
BASED ON THE FACT THAT THE LOW LEVEL SATURATED DECK IS NEARLY A HALF
KM DEEP AND THE LOW LEVEL WIND FIELD SHOULD REMAIN WEAK THROUGH
EARLY AFTERNOON AT LEAST... THESE CLOUDS SHOULD BE TOUGH TO DISLODGE
WITH ANY SWIFTNESS. HAVE SLOWED THE SKY CLEARING BY SEVERAL HOURS.
HAVE ALSO DROPPED HIGHS TODAY BY A FEW DEGREES... TO 56-62... AND
EVEN THESE MAY BE TOO HIGH ESPECIALLY IN THE NE CWA. -GIH
PREVIOUS DISCUSSION FOLLOWS...
THE BACK EDGE OF THE MID AND HIGH LEVEL MOISTURE WAS MOVING EAST
OVER THE PIEDMONT. THIS MAY AID IN THE FOG BECOMING MORE DENSE
THROUGH DAYBREAK OVER THE WESTERN AND SOUTHERN PIEDMONT... AND
POSSIBLY THE SANDHILLS. THEREFORE... WE WILL ISSUE A DENSE FOG
ADVISORY FOR AREAS ALONG AND WEST GREENSBORO TO FAYETTEVILLE
THROUGH 1000 AM.
AS OF 245 AM SATURDAY... THE CURRENT HYBRID COLD AIR DAMMING EPISODE
IS EXPECTED TO LINGER WELL INTO THE LATE MORNING HOURS. THE
LINGERING LOW STATUS AND FOG WILL BE VERY SLOW TO SCOUR OUT THIS
MORNING AS MODELS INDICATE LIGHT WINDS IN THE BOUNDARY LAYER INTO
THE LATE MORNING. CURRENT SURFACE OBS INDICTED CEILINGS AND
VISIBILITIES WERE REMAINING STATUS QUO... EXCEPT FOR LOWERING SOME
OVER DAVIDSON... RANDOLPH... AND STANLY COUNTIES... WHERE WIDESPREAD
VSBYS OF 1/2 TO 1 MILE WERE OBSERVED. WE WILL MONITOR THESE AREAS
CLOSELY. HOWEVER... THE VISIBILITIES ARE EXPECTED TO REMAIN JUST
ABOVE THE THRESHOLD FOR A DENSE FOG ADVISORY.
THE 00Z/NAM WAS THE QUICKEST IN BEGINNING THE CLEARING IN THE LEE OF
THE APPALACHIANS BY MID TO LATE MORNING... WITH THE GFS INDICATING
THE CLEARING WILL BEGIN 3-4 HOURS LATER. GIVEN THE 00Z MODELS LACK
OF ABILITY TO INITIALIZE THE SATURATED BOUNDARY LAYER OVER THE
PIEDMONT DAMMING REGION...AND THE STRENGTH/DEPTH OF THE CAD (3-5K
FEET) BASED ON GSO/RNK 00Z/23 SOUNDINGS... IT APPEARS REASONABLE TO
FAVOR THE SLOWER CLEARING INDICATED BY THE 00Z/GFS. THIS CLEARING
SHOULD GET GOING IN THE LEE OF THE BLUE RIDGE LATE MORNING AS THE
DRY WESTERLY FLOW INCREASES ALOFT WITH THE PASSAGE OF THE MID LEVEL
TROUGH. AS THIS TROUGH MOVES EAST THROUGH CENTRAL NC DURING THE
AFTERNOON... THE CLEARING WILL SPREAD EAST. THERE SHOULD CONTINUE TO
BE SCATTERED TO BROKEN STRATOCUMULUS AT 4-5K FEET EVEN AFTER THE
LOWER STRATUS CLEARS OUT. THUS... WE WILL CONTINUE THE CURRENT
CLOUDY FORECAST THIS MORNING... BECOMING PARTLY CLOUDY THIS
AFTERNOON. THE TEMPERATURES WILL BE HIGHLY DEPENDENT ON HOW MUCH SUN
DEVELOPS THIS AFTERNOON. THE PREVIOUS FORECAST (WHICH LOWERED HIGHS
FOR TODAY) APPEARS VERY REASONABLE. WE WILL CONTINUE THE CURRENT MAX
T FORECASTS INDICATING MID 50S NORTH CENTRAL TO LOWER 60S SE-S.-PWB
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 245 AM SATURDAY...IN THE WAKE OF THE COLD FRONTAL PASSAGE
THIS EVENING... THE SKIES WILL TEMPORARILY BECOME MOSTLY CLEAR
FOR MOST AREAS. THIS WILL BE FOLLOWED BY ANOTHER BOUT OF
STRATUS/STRATOCUMULUS LATER TONIGHT INTO SUNDAY. THIS WILL OCCUR
AS THE LOW LEVEL NE FLOW PULLS ATLANTIC MOISTURE BACK ACROSS OUR
REGION. WHILE MODELS WERE GENERALLY IN AGREEMENT THAT STRATOCUMULUS
WILL EVENTUALLY DEVELOP INTO OUR REGION... THE 00Z/GFS WAS MUCH
FASTER IN SATURATION THE LOW LEVELS ESPECIALLY IN THE EAST
OVERNIGHT... SPREADING WEST BY DAYBREAK. MOSTLY CLEAR OR PARTLY
CLOUDY SKIES EARLY TONIGHT WILL BECOME OVERCAST AGAIN OVERNIGHT.
WITH THIS INCREASINGLY CLOUDY PATTERN TONIGHT... THE WARMER MET
STATISTICAL GUIDANCE WAS PREFERRED OVER THE GFS MOS. LOWS SHOULD
REMAIN IN THE UPPER 30S TO LOWER 40S... INSTEAD OF THE COLDER
LOWER 30S FORECAST BY THE GFS MOS IN THE PIEDMONT.
WITH THE UPPER SHORTWAVE EXPECTED TO MOVE EAST ACROSS THE STATE
DURING THE DAY SUNDAY... THE LIFT AND ASSOCIATED CLOUDINESS ALOFT
WILL COMBINE WITH THE LOW LEVEL MOIST NE FLOW TO KEEP THE
TEMPERATURES ON THE CHILLY SIDE. MAX T`S SUNDAY SHOULD ONLY REACH
THE MID 40S NORTH TO MID 50S SOUTH. THIS UPPER SYSTEM WILL BE
MOISTURE STARVED WITH LITTLE TO NO GULF INFLOW... EXPECT ONLY A
CHANCE OF A FEW SPRINKLES. WE WILL ADVERTISE ONLY A SLIGHT CHANCE
POP FOR ANYTHING THAT MEASURES 0.01. OTHERWISE... ONLY A FEW TRACE
AMOUNTS ARE EXPECTED.
THE UPPER LEVEL DISTURBANCE IS FORECAST TO SHIFT EAST SUNDAY
EVENING AS WEAK HIGH PRESSURE BUILDS IN FROM THE NORTHEAST.
HOWEVER... THE FLOW AT THE SURFACE IS EXPECTED TO REMAIN WEAK...
INDICATING THAT THERE SHOULD STILL BE SOME RESIDUAL LOW LEVEL
MOISTURE AND CLOUDINESS TO DEAL WITH. WE WILL ADVERTISE SKIES TO
BECOME PARTLY CLOUDY AS SUBSIDENCE BEHIND THE DEPARTING SHORT WAVE
FAVORS CLEARING ALOFT. LOWS SHOULD STILL BE ABOVE CURRENT GUIDANCE
AS THE LOW LEVEL MOISTURE SHOULD REMAIN RELATIVE HIGH. EXPECT
MOSTLY MID TO UPPER 30S.
HEIGHTS ARE FORECAST TO RISE ALOFT MONDAY INTO EARLY TUESDAY
AHEAD OF THE NEXT SHORT WAVE TROUGH. THIS WILL BRING MILD TO WARM
TEMPERATURES BACK. THE TRENDS IN THE PAST FEW RUNS HAVE BEEN TO
SPEED UP THIS TROUGH AND THE ASSOCIATED COLD FRONTAL PASSAGE FOR
OUR REGION (NOW APPEARS TO BE DURING THE DAY TUESDAY). THE MAIN
SURFACE STORM TRACK WITH THIS TROUGH IS EXPECTED TO BE WEST TO
EAST THROUGH THE OHIO VALLEY INTO THE NORTHEAST. THE ONLY SHOT AT
SHOWERS FOR CENTRAL NC WILL BE WITH THE TRAILING COLD FRONT
EXPECTED TUESDAY.
SENSIBLE WEATHER MONDAY LOOKS TO BE DRY AND WARMER WITH HIGHS
RETURNING TO THE 60S. INCREASING CLOUDINESS MONDAY NIGHT WITH A
SLIGHT CHANCE OF SHOWERS TOWARD DAYBREAK (NW ONLY). LOWS WILL BE
MILD WITH THE SW FLOW AND INCREASING CLOUDS (MOSTLY MID TO UPPER
40S).
THE SURFACE COLD FRONT SHOULD MOVE THROUGH CENTRAL NC DURING THE
DAY TUESDAY. THE BEST CHANCE OF SIGNIFICANT SHOWERS WILL BE OVER
THE MOUNTAINS. WITH LIMITED DYNAMICS... AND LITTLE IN THE WAY OF
BOUNDARY LAYER INSTABILITY AS THE FRONT MOVES EAST THROUGH CENTRAL
NC... WE SHOULD ONLY SEE A BAND OF LIGHT SHOWERS. QPF WILL BE
FORECAST AT LESS THAN 0.25 OF AN INCH. HIGHS SHOULD STILL REACH
60-65.
STRONG CAA WILL BLOW ACROSS CENTRAL NC BEHIND THE COLD FRONT LATE
TUESDAY AND TUESDAY NIGHT. THE SKIES WILL CLEAR RATHER ABRUPTLY
AFTER THE FROPA WITH STRONG SUBSIDENCE AND DEEP NW FLOW INDICATED
TUESDAY NIGHT. LOWS WILL BE LOWERED INTO THE 25-30 RANGE PER
LATEST GUIDANCE.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
A TRANSIENT POSITIVE PNA PATTERN WILL DEVELOP MIDWEEK RESULTING IN A
LONGWAVE TROUGH AMPLIFYING OVER THE EASTERN PORTION OF THE COUNTRY.
THIS WILL BRING A RETURN OF BELOW NORMAL TEMPERATURES BY WEDNESDAY
AS CANADIAN HIGH PRESSURE BUILDS INTO THE REGION IN THE WAKE OF THE
PREVIOUS NIGHT`S FRONTAL PASSAGE. HIGHS WEDNESDAY SHOULD ONLY MAKE
IT INTO THE UPPER 40S NORTH TO LOWER 50S SOUTH... AND WILL STRUGGLE
TO MAKE IT OUT OF THE MID AND UPPER 40S ON THURSDAY. LOWS WED/THU
NIGHT WILL DIP INTO THE 20S ACROSS MOST OF THE CWA.
AN ALBERTA CLIPPER LOOKS POISED TO APPROACH FROM THE NORTHWEST ON
FRIDAY... SENDING ANOTHER WEAK FRONT THROUGH THE AREA FRIDAY NIGHT.
AS A WEAK SOUTHWEST FLOW DEVELOPS AHEAD OF THE FRONT... TEMPS ARE
APT TO MODERATE SOME DURING THE DAY ON FRIDAY. HIGHS SHOULD REBOUND
CLOSER TO NORMAL LEVELS IN THE LOW TO MID 50S. NO PRECIP IS EXPECTED
AHEAD OF THIS FRONT GIVEN THE DRY NW FLOW REGIME.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 640 AM SATURDAY... LIFR/IFR CONDITIONS WILL CONTINUE THROUGH
THE EARLY MORNING BENEATH A STRONG INVERSION THAT WILL REMAIN AROUND
2K TO 3K FEET THROUGH MOST OF THE MORNING. ALTHOUGH A BIT TOO HIGH
FOR LLWS...AIRCRAFT SHOULD NOTE THAT WINDS NEAR THE INVERSION WILL
REACH AROUND 35KT FROM THE SOUTHWEST THROUGH 15Z WHILE SFC WINDS
REMAIN LIGHT AND VARIABLE. GRADUAL IMPROVEMENT IN CONDITIONS WILL
TAKE PLACE TODAY WITH VISIBILITIES EXPECTED TO BECOME VFR SATURDAY
MORNING AS THE WESTERLY SURFACE FLOW INCREASES. THE LATEST GUIDANCE
HAS DELAYED THE CLEARING OF MVFR/IFR CEILINGS UNTIL LATE THIS
AFTERNOON. THIS IS EVEN WITH THE MODELS NOT FULLING CAPTURING THE
FULL EXTENT OF LOW LEVEL SATURATION SEEN ON THE 00Z/23 GSO SOUNDING.
THEREFORE...HAVE DELAYED VFR CIGS UNTIL LATE AFTERNOON.
LOW CEILINGS LIKELY WILL RETURN LATE SATURDAY NIGHT IN AMPLE
LOW-LEVEL MOISTURE AND A NORTHEAST SURFACE FLOW THAT DEVELOPS
SATURDAY NIGHT OVER CENTRAL NORTH CAROLINA BEHIND A COLD FRONT.
MAINLY MID-LEVEL CLOUDS AND SPRINKLES OR PATCHY LIGHT RAIN ARE
ANTICIPATED BY SUNDAY AFTERNOON WITH THE PASSAGE OF A MODERATE
MID-LEVEL SHORTWAVE. AFTERWARD...THE NEXT...BEST CHANCE FOR MVFR OR
EVEN IFR CONDITIONS WILL BE TUESDAY ALONG AND AHEAD OF A COLD FRONT
THAT WILL SWEEP ACROSS THE STATE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR NCZ021-022-
038-039-073>075-083>086-088.
&&
$$
SYNOPSIS...HARTFIELD
NEAR TERM...HARTFIELD
SHORT TERM...BADGETT
LONG TERM...JFB
AVIATION...JFB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
718 AM EST SAT FEB 23 2008
.SYNOPSIS...
A WEAK LOW PRESSURE WILL LINGER OVER CENTRAL AND EASTERN NORTH
CAROLINA THROUGH MID AFTERNOON... BEFORE MOVING EAST. A COLD
FRONT WILL MOVE SOUTH THROUGH THE AREA THIS EVENING... SHIFTING THE
WINDS TO THE NORTHEAST. A WEAK SURFACE HIGH PRESSURE WILL BUILD
OVERHEAD TONIGHT INTO SUNDAY. AN UPPER LEVEL DISTURBANCE WILL MOVE
ACROSS THE STATE FROM THE WEST SUNDAY... BUT IT WILL REMAIN
MOISTURE STARVED.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 715 AM SATURDAY...
SCATTERED THUNDERSTORMS HAVE DEVELOPED OVER THE NORTHERN PIEDMONT
AND COASTAL PLAIN. NAM BUFR SOUNDINGS INDICATE A FAIRLY UNSTABLE
SOUNDING ABOVE 900 MB. THE RIGHT REAR ENTRANCE OF A 300 MB JET
COMBINED DECENT MID LEVEL COOLING ASSOCIATED WITH A 500 MB
DISTURBANCE IS PRODUCING ENOUGH LIFT TO REALIZE THE ELEVATED
INSTABILITY. SENT A QUICK FORECAST UPDATE TO INCLUDE A CHANCE OF
SHOWERS AND THUNDERSTORMS FOR THE NE CWA THROUGH MID MORNING.
PREVIOUS DISCUSSION FOLLOWS...
THE BACK EDGE OF THE MID AND HIGH LEVEL MOISTURE WAS MOVING EAST
OVER THE PIEDMONT. THIS MAY AID IN THE FOG BECOMING MORE DENSE
THROUGH DAYBREAK OVER THE WESTERN AND SOUTHERN PIEDMONT... AND
POSSIBLY THE SANDHILLS. THEREFORE... WE WILL ISSUE A DENSE FOG
ADVISORY FOR AREAS ALONG AND WEST GREENSBORO TO FAYETTEVILLE
THROUGH 1000 AM.
AS OF 245 AM SATURDAY... THE CURRENT HYBRID COLD AIR DAMMING EPISODE
IS EXPECTED TO LINGER WELL INTO THE LATE MORNING HOURS. THE
LINGERING LOW STATUS AND FOG WILL BE VERY SLOW TO SCOUR OUT THIS
MORNING AS MODELS INDICATE LIGHT WINDS IN THE BOUNDARY LAYER INTO
THE LATE MORNING. CURRENT SURFACE OBS INDICTED CEILINGS AND
VISIBILITIES WERE REMAINING STATUS QUO... EXCEPT FOR LOWERING SOME
OVER DAVIDSON... RANDOLPH... AND STANLY COUNTIES... WHERE WIDESPREAD
VSBYS OF 1/2 TO 1 MILE WERE OBSERVED. WE WILL MONITOR THESE AREAS
CLOSELY. HOWEVER... THE VISIBILITIES ARE EXPECTED TO REMAIN JUST
ABOVE THE THRESHOLD FOR A DENSE FOG ADVISORY.
THE 00Z/NAM WAS THE QUICKEST IN BEGINNING THE CLEARING IN THE LEE OF
THE APPALACHIANS BY MID TO LATE MORNING... WITH THE GFS INDICATING
THE CLEARING WILL BEGIN 3-4 HOURS LATER. GIVEN THE 00Z MODELS LACK
OF ABILITY TO INITIALIZE THE SATURATED BOUNDARY LAYER OVER THE
PIEDMONT DAMMING REGION...AND THE STRENGTH/DEPTH OF THE CAD (3-5K
FEET) BASED ON GSO/RNK 00Z/23 SOUNDINGS... IT APPEARS REASONABLE TO
FAVOR THE SLOWER CLEARING INDICATED BY THE 00Z/GFS. THIS CLEARING
SHOULD GET GOING IN THE LEE OF THE BLUE RIDGE LATE MORNING AS THE
DRY WESTERLY FLOW INCREASES ALOFT WITH THE PASSAGE OF THE MID LEVEL
TROUGH. AS THIS TROUGH MOVES EAST THROUGH CENTRAL NC DURING THE
AFTERNOON... THE CLEARING WILL SPREAD EAST. THERE SHOULD CONTINUE TO
BE SCATTERED TO BROKEN STRATOCUMULUS AT 4-5K FEET EVEN AFTER THE
LOWER STRATUS CLEARS OUT. THUS... WE WILL CONTINUE THE CURRENT
CLOUDY FORECAST THIS MORNING... BECOMING PARTLY CLOUDY THIS
AFTERNOON. THE TEMPERATURES WILL BE HIGHLY DEPENDENT ON HOW MUCH SUN
DEVELOPS THIS AFTERNOON. THE PREVIOUS FORECAST (WHICH LOWERED HIGHS
FOR TODAY) APPEARS VERY REASONABLE. WE WILL CONTINUE THE CURRENT MAX
T FORECASTS INDICATING MID 50S NORTH CENTRAL TO LOWER 60S SE-S.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 245 AM SATURDAY...IN THE WAKE OF THE COLD FRONTAL PASSAGE
THIS EVENING... THE SKIES WILL TEMPORARILY BECOME MOSTLY CLEAR
FOR MOST AREAS. THIS WILL BE FOLLOWED BY ANOTHER BOUT OF
STRATUS/STRATOCUMULUS LATER TONIGHT INTO SUNDAY. THIS WILL OCCUR
AS THE LOW LEVEL NE FLOW PULLS ATLANTIC MOISTURE BACK ACROSS OUR
REGION. WHILE MODELS WERE GENERALLY IN AGREEMENT THAT STRATOCUMULUS
WILL EVENTUALLY DEVELOP INTO OUR REGION... THE 00Z/GFS WAS MUCH
FASTER IN SATURATION THE LOW LEVELS ESPECIALLY IN THE EAST
OVERNIGHT... SPREADING WEST BY DAYBREAK. MOSTLY CLEAR OR PARTLY
CLOUDY SKIES EARLY TONIGHT WILL BECOME OVERCAST AGAIN OVERNIGHT.
WITH THIS INCREASINGLY CLOUDY PATTERN TONIGHT... THE WARMER MET
STATISTICAL GUIDANCE WAS PREFERRED OVER THE GFS MOS. LOWS SHOULD
REMAIN IN THE UPPER 30S TO LOWER 40S... INSTEAD OF THE COLDER
LOWER 30S FORECAST BY THE GFS MOS IN THE PIEDMONT.
WITH THE UPPER SHORTWAVE EXPECTED TO MOVE EAST ACROSS THE STATE
DURING THE DAY SUNDAY... THE LIFT AND ASSOCIATED CLOUDINESS ALOFT
WILL COMBINE WITH THE LOW LEVEL MOIST NE FLOW TO KEEP THE
TEMPERATURES ON THE CHILLY SIDE. MAX T`S SUNDAY SHOULD ONLY REACH
THE MID 40S NORTH TO MID 50S SOUTH. THIS UPPER SYSTEM WILL BE
MOISTURE STARVED WITH LITTLE TO NO GULF INFLOW... EXPECT ONLY A
CHANCE OF A FEW SPRINKLES. WE WILL ADVERTISE ONLY A SLIGHT CHANCE
POP FOR ANYTHING THAT MEASURES 0.01. OTHERWISE... ONLY A FEW TRACE
AMOUNTS ARE EXPECTED.
THE UPPER LEVEL DISTURBANCE IS FORECAST TO SHIFT EAST SUNDAY
EVENING AS WEAK HIGH PRESSURE BUILDS IN FROM THE NORTHEAST.
HOWEVER... THE FLOW AT THE SURFACE IS EXPECTED TO REMAIN WEAK...
INDICATING THAT THERE SHOULD STILL BE SOME RESIDUAL LOW LEVEL
MOISTURE AND CLOUDINESS TO DEAL WITH. WE WILL ADVERTISE SKIES TO
BECOME PARTLY CLOUDY AS SUBSIDENCE BEHIND THE DEPARTING SHORT WAVE
FAVORS CLEARING ALOFT. LOWS SHOULD STILL BE ABOVE CURRENT GUIDANCE
AS THE LOW LEVEL MOISTURE SHOULD REMAIN RELATIVE HIGH. EXPECT
MOSTLY MID TO UPPER 30S.
HEIGHTS ARE FORECAST TO RISE ALOFT MONDAY INTO EARLY TUESDAY
AHEAD OF THE NEXT SHORT WAVE TROUGH. THIS WILL BRING MILD TO WARM
TEMPERATURES BACK. THE TRENDS IN THE PAST FEW RUNS HAVE BEEN TO
SPEED UP THIS TROUGH AND THE ASSOCIATED COLD FRONTAL PASSAGE FOR
OUR REGION (NOW APPEARS TO BE DURING THE DAY TUESDAY). THE MAIN
SURFACE STORM TRACK WITH THIS TROUGH IS EXPECTED TO BE WEST TO
EAST THROUGH THE OHIO VALLEY INTO THE NORTHEAST. THE ONLY SHOT AT
SHOWERS FOR CENTRAL NC WILL BE WITH THE TRAILING COLD FRONT
EXPECTED TUESDAY.
SENSIBLE WEATHER MONDAY LOOKS TO BE DRY AND WARMER WITH HIGHS
RETURNING TO THE 60S. INCREASING CLOUDINESS MONDAY NIGHT WITH A
SLIGHT CHANCE OF SHOWERS TOWARD DAYBREAK (NW ONLY). LOWS WILL BE
MILD WITH THE SW FLOW AND INCREASING CLOUDS (MOSTLY MID TO UPPER
40S).
THE SURFACE COLD FRONT SHOULD MOVE THROUGH CENTRAL NC DURING THE
DAY TUESDAY. THE BEST CHANCE OF SIGNIFICANT SHOWERS WILL BE OVER
THE MOUNTAINS. WITH LIMITED DYNAMICS... AND LITTLE IN THE WAY OF
BOUNDARY LAYER INSTABILITY AS THE FRONT MOVES EAST THROUGH CENTRAL
NC... WE SHOULD ONLY SEE A BAND OF LIGHT SHOWERS. QPF WILL BE
FORECAST AT LESS THAN 0.25 OF AN INCH. HIGHS SHOULD STILL REACH
60-65.
STRONG CAA WILL BLOW ACROSS CENTRAL NC BEHIND THE COLD FRONT LATE
TUESDAY AND TUESDAY NIGHT. THE SKIES WILL CLEAR RATHER ABRUPTLY
AFTER THE FROPA WITH STRONG SUBSIDENCE AND DEEP NW FLOW INDICATED
TUESDAY NIGHT. LOWS WILL BE LOWERED INTO THE 25-30 RANGE PER
LATEST GUIDANCE.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
A TRANSIENT POSITIVE PNA PATTERN WILL DEVELOP MIDWEEK RESULTING IN A
LONGWAVE TROUGH AMPLIFYING OVER THE EASTERN PORTION OF THE COUNTRY.
THIS WILL BRING A RETURN OF BELOW NORMAL TEMPERATURES BY WEDNESDAY
AS CANADIAN HIGH PRESSURE BUILDS INTO THE REGION IN THE WAKE OF THE
PREVIOUS NIGHT`S FRONTAL PASSAGE. HIGHS WEDNESDAY SHOULD ONLY MAKE
IT INTO THE UPPER 40S NORTH TO LOWER 50S SOUTH... AND WILL STRUGGLE
TO MAKE IT OUT OF THE MID AND UPPER 40S ON THURSDAY. LOWS WED/THU
NIGHT WILL DIP INTO THE 20S ACROSS MOST OF THE CWA.
AN ALBERTA CLIPPER LOOKS POISED TO APPROACH FROM THE NORTHWEST ON
FRIDAY... SENDING ANOTHER WEAK FRONT THROUGH THE AREA FRIDAY NIGHT.
AS A WEAK SOUTHWEST FLOW DEVELOPS AHEAD OF THE FRONT... TEMPS ARE
APT TO MODERATE SOME DURING THE DAY ON FRIDAY. HIGHS SHOULD REBOUND
CLOSER TO NORMAL LEVELS IN THE LOW TO MID 50S. NO PRECIP IS EXPECTED
AHEAD OF THIS FRONT GIVEN THE DRY NW FLOW REGIME.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 640 AM SATURDAY... LIFR/IFR CONDITIONS WILL CONTINUE THROUGH
THE EARLY MORNING BENEATH A STRONG INVERSION THAT WILL REMAIN AROUND
2K TO 3K FEET THROUGH MOST OF THE MORNING. ALTHOUGH A BIT TOO HIGH
FOR LLWS...AIRCRAFT SHOULD NOTE THAT WINDS NEAR THE INVERSION WILL
REACH AROUND 35KT FROM THE SOUTHWEST THROUGH 15Z WHILE SFC WINDS
REMAIN LIGHT AND VARIABLE. GRADUAL IMPROVEMENT IN CONDITIONS WILL
TAKE PLACE TODAY WITH VISIBILITIES EXPECTED TO BECOME VFR SATURDAY
MORNING AS THE WESTERLY SURFACE FLOW INCREASES. THE LATEST GUIDANCE
HAS DELAYED THE CLEARING OF MVFR/IFR CEILINGS UNTIL LATE THIS
AFTERNOON. THIS IS EVEN WITH THE MODELS NOT FULLING CAPTURING THE
FULL EXTENT OF LOW LEVEL SATURATION SEEN ON THE 00Z/23 GSO SOUNDING.
THEREFORE...HAVE DELAYED VFR CIGS UNTIL LATE AFTERNOON.
LOW CEILINGS LIKELY WILL RETURN LATE SATURDAY NIGHT IN AMPLE
LOW-LEVEL MOISTURE AND A NORTHEAST SURFACE FLOW THAT DEVELOPS
SATURDAY NIGHT OVER CENTRAL NORTH CAROLINA BEHIND A COLD FRONT.
MAINLY MID-LEVEL CLOUDS AND SPRINKLES OR PATCHY LIGHT RAIN ARE
ANTICIPATED BY SUNDAY AFTERNOON WITH THE PASSAGE OF A MODERATE
MID-LEVEL SHORTWAVE. AFTERWARD...THE NEXT...BEST CHANCE FOR MVFR OR
EVEN IFR CONDITIONS WILL BE TUESDAY ALONG AND AHEAD OF A COLD FRONT
THAT WILL SWEEP ACROSS THE STATE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR NCZ021-022-
038-039-073>075-083>086-088.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BADGETT/JFB
SHORT TERM...BADGETT
LONG TERM...JFB
AVIATION...JFB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
644 AM EST SAT FEB 23 2008
.SYNOPSIS...
A WEAK LOW PRESSURE WILL LINGER OVER CENTRAL AND EASTERN NORTH
CAROLINA THROUGH MID AFTERNOON... BEFORE MOVING EAST. A COLD
FRONT WILL MOVE SOUTH THROUGH THE AREA THIS EVENING... SHIFTING THE
WINDS TO THE NORTHEAST. A WEAK SURFACE HIGH PRESSURE WILL BUILD
OVERHEAD TONIGHT INTO SUNDAY. AN UPPER LEVEL DISTURBANCE WILL MOVE
ACROSS THE STATE FROM THE WEST SUNDAY... BUT IT WILL REMAIN
MOISTURE STARVED.
&&
.NEAR TERM /THROUGH TONIGHT/...
...AS OF 530 AM...
THE BACK EDGE OF THE MID AND HIGH LEVEL MOISTURE WAS MOVING EAST
OVER THE PIEDMONT. THIS MAY AID IN THE FOG BECOMING MORE DENSE
THROUGH DAYBREAK OVER THE WESTERN AND SOUTHERN PIEDMONT... AND
POSSIBLY THE SANDHILLS. THEREFORE... WE WILL ISSUE A DENSE FOG
ADVISORY FOR AREAS ALONG AND WEST GREENSBORO TO FAYETTEVILLE
THROUGH 1000 AM.
PREVIOUS DISCUSSION...
AS OF 245 AM...
...CONSIDERING A DENSE FOG ADVISORY FOR PORTIONS OF THE WESTERN
PIEDMONT... MAINLY SW OF THE PIEDMONT TRIAD REGION MORNING...
OTHERWISE SLOW CLEARING OF LOW STRATUS AND FOG EXPECTED LATE MORNING
INTO THE EARLY AFTERNOON...
...RADAR TRENDS INDICATE NOTHING MORE THAN SPRINKLES FOR OUR SE
COUNTIES THROUGH DAYBREAK...
AS OF 245 AM SATURDAY... THE CURRENT HYBRID COLD AIR DAMMING
EPISODE IS EXPECTED TO LINGER WELL INTO THE LATE MORNING HOURS.
THE LINGERING LOW STATUS AND FOG WILL BE VERY SLOW TO SCOUR OUT
THIS MORNING AS MODELS INDICATE LIGHT WINDS IN THE BOUNDARY LAYER
INTO THE LATE MORNING. CURRENT SURFACE OBS INDICTED CEILINGS AND
VISIBILITIES WERE REMAINING STATUS QUO... EXCEPT FOR LOWERING SOME
OVER DAVIDSON... RANDOLPH... AND STANLY COUNTIES... WHERE WIDESPREAD
VSBYS OF 1/2 TO 1 MILE WERE OBSERVED. WE WILL MONITOR THESE AREAS
CLOSELY. HOWEVER... THE VISIBILITIES ARE EXPECTED TO REMAIN JUST
ABOVE THE THRESHOLD FOR A DENSE FOG ADVISORY.
THE 00Z/NAM WAS THE QUICKEST IN BEGINNING THE CLEARING IN THE LEE OF
THE APPALACHIANS BY MID TO LATE MORNING... WITH THE GFS INDICATING
THE CLEARING WILL BEGIN 3-4 HOURS LATER. GIVEN THE 00Z MODELS LACK
OF ABILITY TO INITIALIZE THE SATURATED BOUNDARY LAYER OVER THE
PIEDMONT DAMMING REGION...AND THE STRENGTH/DEPTH OF THE CAD (3-5K
FEET) BASED ON GSO/RNK 00Z/23 SOUNDINGS... IT APPEARS REASONABLE TO
FAVOR THE SLOWER CLEARING INDICATED BY THE 00Z/GFS. THIS CLEARING
SHOULD GET GOING IN THE LEE OF THE BLUE RIDGE LATE MORNING AS THE
DRY WESTERLY FLOW INCREASES ALOFT WITH THE PASSAGE OF THE MID LEVEL
TROUGH. AS THIS TROUGH MOVES EAST THROUGH CENTRAL NC DURING THE
AFTERNOON... THE CLEARING WILL SPREAD EAST. THERE SHOULD CONTINUE TO
BE SCATTERED TO BROKEN STRATOCUMULUS AT 4-5K FEET EVEN AFTER THE
LOWER STRATUS CLEARS OUT. THUS... WE WILL CONTINUE THE CURRENT
CLOUDY FORECAST THIS MORNING... BECOMING PARTLY CLOUDY THIS
AFTERNOON. THE TEMPERATURES WILL BE HIGHLY DEPENDENT ON HOW MUCH SUN
DEVELOPS THIS AFTERNOON. THE PREVIOUS FORECAST (WHICH LOWERED HIGHS
FOR TODAY) APPEARS VERY REASONABLE. WE WILL CONTINUE THE CURRENT MAX
T FORECASTS INDICATING MID 50S NORTH CENTRAL TO LOWER 60S SE-S.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 245 AM SATURDAY...IN THE WAKE OF THE COLD FRONTAL PASSAGE
THIS EVENING... THE SKIES WILL TEMPORARILY BECOME MOSTLY CLEAR
FOR MOST AREAS. THIS WILL BE FOLLOWED BY ANOTHER BOUT OF
STRATUS/STRATOCUMULUS LATER TONIGHT INTO SUNDAY. THIS WILL OCCUR
AS THE LOW LEVEL NE FLOW PULLS ATLANTIC MOISTURE BACK ACROSS OUR
REGION. WHILE MODELS WERE GENERALLY IN AGREEMENT THAT STRATOCUMULUS
WILL EVENTUALLY DEVELOP INTO OUR REGION... THE 00Z/GFS WAS MUCH
FASTER IN SATURATION THE LOW LEVELS ESPECIALLY IN THE EAST
OVERNIGHT... SPREADING WEST BY DAYBREAK. MOSTLY CLEAR OR PARTLY
CLOUDY SKIES EARLY TONIGHT WILL BECOME OVERCAST AGAIN OVERNIGHT.
WITH THIS INCREASINGLY CLOUDY PATTERN TONIGHT... THE WARMER MET
STATISTICAL GUIDANCE WAS PREFERRED OVER THE GFS MOS. LOWS SHOULD
REMAIN IN THE UPPER 30S TO LOWER 40S... INSTEAD OF THE COLDER
LOWER 30S FORECAST BY THE GFS MOS IN THE PIEDMONT.
WITH THE UPPER SHORTWAVE EXPECTED TO MOVE EAST ACROSS THE STATE
DURING THE DAY SUNDAY... THE LIFT AND ASSOCIATED CLOUDINESS ALOFT
WILL COMBINE WITH THE LOW LEVEL MOIST NE FLOW TO KEEP THE
TEMPERATURES ON THE CHILLY SIDE. MAX T`S SUNDAY SHOULD ONLY REACH
THE MID 40S NORTH TO MID 50S SOUTH. THIS UPPER SYSTEM WILL BE
MOISTURE STARVED WITH LITTLE TO NO GULF INFLOW... EXPECT ONLY A
CHANCE OF A FEW SPRINKLES. WE WILL ADVERTISE ONLY A SLIGHT CHANCE
POP FOR ANYTHING THAT MEASURES 0.01. OTHERWISE... ONLY A FEW TRACE
AMOUNTS ARE EXPECTED.
THE UPPER LEVEL DISTURBANCE IS FORECAST TO SHIFT EAST SUNDAY
EVENING AS WEAK HIGH PRESSURE BUILDS IN FROM THE NORTHEAST.
HOWEVER... THE FLOW AT THE SURFACE IS EXPECTED TO REMAIN WEAK...
INDICATING THAT THERE SHOULD STILL BE SOME RESIDUAL LOW LEVEL
MOISTURE AND CLOUDINESS TO DEAL WITH. WE WILL ADVERTISE SKIES TO
BECOME PARTLY CLOUDY AS SUBSIDENCE BEHIND THE DEPARTING SHORT WAVE
FAVORS CLEARING ALOFT. LOWS SHOULD STILL BE ABOVE CURRENT GUIDANCE
AS THE LOW LEVEL MOISTURE SHOULD REMAIN RELATIVE HIGH. EXPECT
MOSTLY MID TO UPPER 30S.
HEIGHTS ARE FORECAST TO RISE ALOFT MONDAY INTO EARLY TUESDAY
AHEAD OF THE NEXT SHORT WAVE TROUGH. THIS WILL BRING MILD TO WARM
TEMPERATURES BACK. THE TRENDS IN THE PAST FEW RUNS HAVE BEEN TO
SPEED UP THIS TROUGH AND THE ASSOCIATED COLD FRONTAL PASSAGE FOR
OUR REGION (NOW APPEARS TO BE DURING THE DAY TUESDAY). THE MAIN
SURFACE STORM TRACK WITH THIS TROUGH IS EXPECTED TO BE WEST TO
EAST THROUGH THE OHIO VALLEY INTO THE NORTHEAST. THE ONLY SHOT AT
SHOWERS FOR CENTRAL NC WILL BE WITH THE TRAILING COLD FRONT
EXPECTED TUESDAY.
SENSIBLE WEATHER MONDAY LOOKS TO BE DRY AND WARMER WITH HIGHS
RETURNING TO THE 60S. INCREASING CLOUDINESS MONDAY NIGHT WITH A
SLIGHT CHANCE OF SHOWERS TOWARD DAYBREAK (NW ONLY). LOWS WILL BE
MILD WITH THE SW FLOW AND INCREASING CLOUDS (MOSTLY MID TO UPPER
40S).
THE SURFACE COLD FRONT SHOULD MOVE THROUGH CENTRAL NC DURING THE
DAY TUESDAY. THE BEST CHANCE OF SIGNIFICANT SHOWERS WILL BE OVER
THE MOUNTAINS. WITH LIMITED DYNAMICS... AND LITTLE IN THE WAY OF
BOUNDARY LAYER INSTABILITY AS THE FRONT MOVES EAST THROUGH CENTRAL
NC... WE SHOULD ONLY SEE A BAND OF LIGHT SHOWERS. QPF WILL BE
FORECAST AT LESS THAN 0.25 OF AN INCH. HIGHS SHOULD STILL REACH
60-65.
STRONG CAA WILL BLOW ACROSS CENTRAL NC BEHIND THE COLD FRONT LATE
TUESDAY AND TUESDAY NIGHT. THE SKIES WILL CLEAR RATHER ABRUPTLY
AFTER THE FROPA WITH STRONG SUBSIDENCE AND DEEP NW FLOW INDICATED
TUESDAY NIGHT. LOWS WILL BE LOWERED INTO THE 25-30 RANGE PER
LATEST GUIDANCE.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
A TRANSIENT POSITIVE PNA PATTERN WILL DEVELOP MIDWEEK RESULTING IN A
LONGWAVE TROUGH AMPLIFYING OVER THE EASTERN PORTION OF THE COUNTRY.
THIS WILL BRING A RETURN OF BELOW NORMAL TEMPERATURES BY WEDNESDAY
AS CANADIAN HIGH PRESSURE BUILDS INTO THE REGION IN THE WAKE OF THE
PREVIOUS NIGHT`S FRONTAL PASSAGE. HIGHS WEDNESDAY SHOULD ONLY MAKE
IT INTO THE UPPER 40S NORTH TO LOWER 50S SOUTH... AND WILL STRUGGLE
TO MAKE IT OUT OF THE MID AND UPPER 40S ON THURSDAY. LOWS WED/THU
NIGHT WILL DIP INTO THE 20S ACROSS MOST OF THE CWA.
AN ALBERTA CLIPPER LOOKS POISED TO APPROACH FROM THE NORTHWEST ON
FRIDAY... SENDING ANOTHER WEAK FRONT THROUGH THE AREA FRIDAY NIGHT.
AS A WEAK SOUTHWEST FLOW DEVELOPS AHEAD OF THE FRONT... TEMPS ARE
APT TO MODERATE SOME DURING THE DAY ON FRIDAY. HIGHS SHOULD REBOUND
CLOSER TO NORMAL LEVELS IN THE LOW TO MID 50S. NO PRECIP IS EXPECTED
AHEAD OF THIS FRONT GIVEN THE DRY NW FLOW REGIME.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 640 AM SATURDAY... LIFR/IFR CONDITIONS WILL CONTINUE THROUGH
THE EARLY MORNING BENEATH A STRONG INVERSION THAT WILL REMAIN AROUND
2K TO 3K FEET THROUGH MOST OF THE MORNING. ALTHOUGH A BIT TOO HIGH
FOR LLWS...AIRCRAFT SHOULD NOTE THAT WINDS NEAR THE INVERSION WILL
REACH AROUND 35KT FROM THE SOUTHWEST THROUGH 15Z WHILE SFC WINDS
REMAIN LIGHT AND VARIABLE. GRADUAL IMPROVEMENT IN CONDITIONS WILL
TAKE PLACE TODAY WITH VISIBILITIES EXPECTED TO BECOME VFR SATURDAY
MORNING AS THE WESTERLY SURFACE FLOW INCREASES. THE LATEST GUIDANCE
HAS DELAYED THE CLEARING OF MVFR/IFR CEILINGS UNTIL LATE THIS
AFTERNOON. THIS IS EVEN WITH THE MODELS NOT FULLING CAPTURING THE
FULL EXTENT OF LOW LEVEL SATURATION SEEN ON THE 00Z/23 GSO SOUNDING.
THEREFORE...HAVE DELAYED VFR CIGS UNTIL LATE AFTERNOON.
LOW CEILINGS LIKELY WILL RETURN LATE SATURDAY NIGHT IN AMPLE
LOW-LEVEL MOISTURE AND A NORTHEAST SURFACE FLOW THAT DEVELOPS
SATURDAY NIGHT OVER CENTRAL NORTH CAROLINA BEHIND A COLD FRONT.
MAINLY MID-LEVEL CLOUDS AND SPRINKLES OR PATCHY LIGHT RAIN ARE
ANTICIPATED BY SUNDAY AFTERNOON WITH THE PASSAGE OF A MODERATE
MID-LEVEL SHORTWAVE. AFTERWARD...THE NEXT...BEST CHANCE FOR MVFR OR
EVEN IFR CONDITIONS WILL BE TUESDAY ALONG AND AHEAD OF A COLD FRONT
THAT WILL SWEEP ACROSS THE STATE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR NCZ021-022-
038-039-073>075-083>086-088.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BADGETT/JFB
SHORT TERM...BADGETT
LONG TERM...JFB
AVIATION...JFB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
530 AM EST SAT FEB 23 2008
.SYNOPSIS...
A WEAK LOW PRESSURE WILL LINGER OVER CENTRAL AND EASTERN NORTH
CAROLINA THROUGH MID AFTERNOON... BEFORE MOVING EAST. A COLD
FRONT WILL MOVE SOUTH THROUGH THE AREA THIS EVENING... SHIFTING THE
WINDS TO THE NORTHEAST. A WEAK SURFACE HIGH PRESSURE WILL BUILD
OVERHEAD TONIGHT INTO SUNDAY. AN UPPER LEVEL DISTURBANCE WILL MOVE
ACROSS THE STATE FROM THE WEST SUNDAY... BUT IT WILL REMAIN
MOISTURE STARVED.
&&
.NEAR TERM /THROUGH TONIGHT/...
...AS OF 530 AM...
THE BACK EDGE OF THE MID AND HIGH LEVEL MOISTURE WAS MOVING EAST
OVER THE PIEDMONT. THIS MAY AID IN THE FOG BECOMING MORE DENSE
THROUGH DAYBREAK OVER THE WESTERN AND SOUTHERN PIEDMONT... AND
POSSIBLY THE SANDHILLS. THEREFORE... WE WILL ISSUE A DENSE FOG
ADVISORY FOR AREAS ALONG AND WEST GREENSBORO TO FAYETTEVILLE
THROUGH 1000 AM.
PREVIOUS DISCUSSION...
AS OF 245 AM...
...CONSIDERING A DENSE FOG ADVISORY FOR PORTIONS OF THE WESTERN
PIEDMONT... MAINLY SW OF THE PIEDMONT TRIAD REGION MORNING...
OTHERWISE SLOW CLEARING OF LOW STRATUS AND FOG EXPECTED LATE MORNING
INTO THE EARLY AFTERNOON...
...RADAR TRENDS INDICATE NOTHING MORE THAN SPRINKLES FOR OUR SE
COUNTIES THROUGH DAYBREAK...
AS OF 245 AM SATURDAY... THE CURRENT HYBRID COLD AIR DAMMING
EPISODE IS EXPECTED TO LINGER WELL INTO THE LATE MORNING HOURS.
THE LINGERING LOW STATUS AND FOG WILL BE VERY SLOW TO SCOUR OUT
THIS MORNING AS MODELS INDICATE LIGHT WINDS IN THE BOUNDARY LAYER
INTO THE LATE MORNING. CURRENT SURFACE OBS INDICTED CEILINGS AND
VISIBILITIES WERE REMAINING STATUS QUO... EXCEPT FOR LOWERING SOME
OVER DAVIDSON... RANDOLPH... AND STANLY COUNTIES... WHERE WIDESPREAD
VSBYS OF 1/2 TO 1 MILE WERE OBSERVED. WE WILL MONITOR THESE AREAS
CLOSELY. HOWEVER... THE VISIBILITIES ARE EXPECTED TO REMAIN JUST
ABOVE THE THRESHOLD FOR A DENSE FOG ADVISORY.
THE 00Z/NAM WAS THE QUICKEST IN BEGINNING THE CLEARING IN THE LEE OF
THE APPALACHIANS BY MID TO LATE MORNING... WITH THE GFS INDICATING
THE CLEARING WILL BEGIN 3-4 HOURS LATER. GIVEN THE 00Z MODELS LACK
OF ABILITY TO INITIALIZE THE SATURATED BOUNDARY LAYER OVER THE
PIEDMONT DAMMING REGION...AND THE STRENGTH/DEPTH OF THE CAD (3-5K
FEET) BASED ON GSO/RNK 00Z/23 SOUNDINGS... IT APPEARS REASONABLE TO
FAVOR THE SLOWER CLEARING INDICATED BY THE 00Z/GFS. THIS CLEARING
SHOULD GET GOING IN THE LEE OF THE BLUE RIDGE LATE MORNING AS THE
DRY WESTERLY FLOW INCREASES ALOFT WITH THE PASSAGE OF THE MID LEVEL
TROUGH. AS THIS TROUGH MOVES EAST THROUGH CENTRAL NC DURING THE
AFTERNOON... THE CLEARING WILL SPREAD EAST. THERE SHOULD CONTINUE TO
BE SCATTERED TO BROKEN STRATOCUMULUS AT 4-5K FEET EVEN AFTER THE
LOWER STRATUS CLEARS OUT. THUS... WE WILL CONTINUE THE CURRENT
CLOUDY FORECAST THIS MORNING... BECOMING PARTLY CLOUDY THIS
AFTERNOON. THE TEMPERATURES WILL BE HIGHLY DEPENDENT ON HOW MUCH SUN
DEVELOPS THIS AFTERNOON. THE PREVIOUS FORECAST (WHICH LOWERED HIGHS
FOR TODAY) APPEARS VERY REASONABLE. WE WILL CONTINUE THE CURRENT MAX
T FORECASTS INDICATING MID 50S NORTH CENTRAL TO LOWER 60S SE-S.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
AS OF 245 AM SATURDAY...IN THE WAKE OF THE COLD FRONTAL PASSAGE
THIS EVENING... THE SKIES WILL TEMPORARILY BECOME MOSTLY CLEAR
FOR MOST AREAS. THIS WILL BE FOLLOWED BY ANOTHER BOUT OF
STRATUS/STRATOCUMULUS LATER TONIGHT INTO SUNDAY. THIS WILL OCCUR
AS THE LOW LEVEL NE FLOW PULLS ATLANTIC MOISTURE BACK ACROSS OUR
REGION. WHILE MODELS WERE GENERALLY IN AGREEMENT THAT STRATOCUMULUS
WILL EVENTUALLY DEVELOP INTO OUR REGION... THE 00Z/GFS WAS MUCH
FASTER IN SATURATION THE LOW LEVELS ESPECIALLY IN THE EAST
OVERNIGHT... SPREADING WEST BY DAYBREAK. MOSTLY CLEAR OR PARTLY
CLOUDY SKIES EARLY TONIGHT WILL BECOME OVERCAST AGAIN OVERNIGHT.
WITH THIS INCREASINGLY CLOUDY PATTERN TONIGHT... THE WARMER MET
STATISTICAL GUIDANCE WAS PREFERRED OVER THE GFS MOS. LOWS SHOULD
REMAIN IN THE UPPER 30S TO LOWER 40S... INSTEAD OF THE COLDER
LOWER 30S FORECAST BY THE GFS MOS IN THE PIEDMONT.
WITH THE UPPER SHORTWAVE EXPECTED TO MOVE EAST ACROSS THE STATE
DURING THE DAY SUNDAY... THE LIFT AND ASSOCIATED CLOUDINESS ALOFT
WILL COMBINE WITH THE LOW LEVEL MOIST NE FLOW TO KEEP THE
TEMPERATURES ON THE CHILLY SIDE. MAX T`S SUNDAY SHOULD ONLY REACH
THE MID 40S NORTH TO MID 50S SOUTH. THIS UPPER SYSTEM WILL BE
MOISTURE STARVED WITH LITTLE TO NO GULF INFLOW... EXPECT ONLY A
CHANCE OF A FEW SPRINKLES. WE WILL ADVERTISE ONLY A SLIGHT CHANCE
POP FOR ANYTHING THAT MEASURES 0.01. OTHERWISE... ONLY A FEW TRACE
AMOUNTS ARE EXPECTED.
THE UPPER LEVEL DISTURBANCE IS FORECAST TO SHIFT EAST SUNDAY
EVENING AS WEAK HIGH PRESSURE BUILDS IN FROM THE NORTHEAST.
HOWEVER... THE FLOW AT THE SURFACE IS EXPECTED TO REMAIN WEAK...
INDICATING THAT THERE SHOULD STILL BE SOME RESIDUAL LOW LEVEL
MOISTURE AND CLOUDINESS TO DEAL WITH. WE WILL ADVERTISE SKIES TO
BECOME PARTLY CLOUDY AS SUBSIDENCE BEHIND THE DEPARTING SHORT WAVE
FAVORS CLEARING ALOFT. LOWS SHOULD STILL BE ABOVE CURRENT GUIDANCE
AS THE LOW LEVEL MOISTURE SHOULD REMAIN RELATIVE HIGH. EXPECT
MOSTLY MID TO UPPER 30S.
HEIGHTS ARE FORECAST TO RISE ALOFT MONDAY INTO EARLY TUESDAY
AHEAD OF THE NEXT SHORT WAVE TROUGH. THIS WILL BRING MILD TO WARM
TEMPERATURES BACK. THE TRENDS IN THE PAST FEW RUNS HAVE BEEN TO
SPEED UP THIS TROUGH AND THE ASSOCIATED COLD FRONTAL PASSAGE FOR
OUR REGION (NOW APPEARS TO BE DURING THE DAY TUESDAY). THE MAIN
SURFACE STORM TRACK WITH THIS TROUGH IS EXPECTED TO BE WEST TO
EAST THROUGH THE OHIO VALLEY INTO THE NORTHEAST. THE ONLY SHOT AT
SHOWERS FOR CENTRAL NC WILL BE WITH THE TRAILING COLD FRONT
EXPECTED TUESDAY.
SENSIBLE WEATHER MONDAY LOOKS TO BE DRY AND WARMER WITH HIGHS
RETURNING TO THE 60S. INCREASING CLOUDINESS MONDAY NIGHT WITH A
SLIGHT CHANCE OF SHOWERS TOWARD DAYBREAK (NW ONLY). LOWS WILL BE
MILD WITH THE SW FLOW AND INCREASING CLOUDS (MOSTLY MID TO UPPER
40S).
THE SURFACE COLD FRONT SHOULD MOVE THROUGH CENTRAL NC DURING THE
DAY TUESDAY. THE BEST CHANCE OF SIGNIFICANT SHOWERS WILL BE OVER
THE MOUNTAINS. WITH LIMITED DYNAMICS... AND LITTLE IN THE WAY OF
BOUNDARY LAYER INSTABILITY AS THE FRONT MOVES EAST THROUGH CENTRAL
NC... WE SHOULD ONLY SEE A BAND OF LIGHT SHOWERS. QPF WILL BE
FORECAST AT LESS THAN 0.25 OF AN INCH. HIGHS SHOULD STILL REACH
60-65.
STRONG CAA WILL BLOW ACROSS CENTRAL NC BEHIND THE COLD FRONT LATE
TUESDAY AND TUESDAY NIGHT. THE SKIES WILL CLEAR RATHER ABRUPTLY
AFTER THE FROPA WITH STRONG SUBSIDENCE AND DEEP NW FLOW INDICATED
TUESDAY NIGHT. LOWS WILL BE LOWERED INTO THE 25-30 RANGE PER
LATEST GUIDANCE.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
A TRANSIENT POSITIVE PNA PATTERN WILL DEVELOP MIDWEEK RESULTING IN A
LONGWAVE TROUGH AMPLIFYING OVER THE EASTERN PORTION OF THE COUNTRY.
THIS WILL BRING A RETURN OF BELOW NORMAL TEMPERATURES BY WEDNESDAY
AS CANADIAN HIGH PRESSURE BUILDS INTO THE REGION IN THE WAKE OF THE
PREVIOUS NIGHT`S FRONTAL PASSAGE. HIGHS WEDNESDAY SHOULD ONLY MAKE
IT INTO THE UPPER 40S NORTH TO LOWER 50S SOUTH... AND WILL STRUGGLE
TO MAKE IT OUT OF THE MID AND UPPER 40S ON THURSDAY. LOWS WED/THU
NIGHT WILL DIP INTO THE 20S ACROSS MOST OF THE CWA.
AN ALBERTA CLIPPER LOOKS POISED TO APPROACH FROM THE NORTHWEST ON
FRIDAY... SENDING ANOTHER WEAK FRONT THROUGH THE AREA FRIDAY NIGHT.
AS A WEAK SOUTHWEST FLOW DEVELOPS AHEAD OF THE FRONT... TEMPS ARE
APT TO MODERATE SOME DURING THE DAY ON FRIDAY. HIGHS SHOULD REBOUND
CLOSER TO NORMAL LEVELS IN THE LOW TO MID 50S. NO PRECIP IS EXPECTED
AHEAD OF THIS FRONT GIVEN THE DRY NW FLOW REGIME.
&&
.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
AS OF 1230 AM SATURDAY...IFR CONDITIONS AND OFTEN LIFR CONDITIONS
DUE TO CEILINGS WILL BE IN PLACE OVERNIGHT BENEATH STRONG INVERSION
THAT WILL REMAIN AROUND 2K TO 3K FEET AT LEAST THROUGH 12Z.
ALTHOUGH A BIT TOO HIGH FOR LLWS...AIRCRAFT SHOULD NOTE THAT WINDS
NEAR THE INVERSION...ESPECIALLY TOWARD KFAY...COULD REACH AROUND
35KT FROM THE SOUTHWEST BETWEEN 09Z AND 12Z. GRADUAL IMPROVEMENT IN
CONDITIONS WILL TAKE PLACE SATURDAY...WITH VISIBILITIES EXPECTED TO
BECOME VFR SATURDAY MORNING AS THE WESTERLY SURFACE FLOW INCREASES...
FOLLOWED BY VFR CEILINGS MAINLY IN THE AFTERNOON IN THE
DEEP...WESTERLY FLOW AS NOTED ON GFS AND NAM BUFR SOUNDINGS.
LOW CEILINGS LIKELY WILL RETURN LATE SATURDAY NIGHT IN AMPLE
LOW-LEVEL MOISTURE AND A NORTHEAST SURFACE FLOW THAT DEVELOPS
SATURDAY NIGHT OVER CENTRAL NORTH CAROLINA BEHIND A COLD FRONT.
MAINLY MID-LEVEL CLOUDS AND SPRINKLES OR PATCHY LIGHT RAIN ARE
ANTICIPATED BY SUNDAY AFTERNOON WITH THE PASSAGE OF A MODERATE
MID-LEVEL SHORTWAVE. AFTERWARD...THE NEXT...BEST CHANCE FOR MVFR OR
EVEN IFR CONDITIONS WILL BE TUESDAY ALONG AND AHEAD OF A COLD FRONT
THAT WILL SWEEP ACROSS THE STATE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR NCZ021-022-
038-039-073>075-083>086-088.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BADGETT/JFB
SHORT TERM...BADGETT
LONG TERM...JFB
AVIATION...JFB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
252 AM EST SAT FEB 23 2008
.SYNOPSIS...
A WEAK LOW PRESSURE WILL LINGER OVER CENTRAL AND EASTERN NORTH
CAROLINA THROUGH MID AFTERNOON... BEFORE MOVING EAST. A COLD
FRONT WILL MOVE SOUTH THROUGH THE AREA THIS EVENING... SHIFTING THE
WINDS TO THE NORTHEAST. A WEAK SURFACE HIGH PRESSURE WILL BUILD
OVERHEAD TONIGHT INTO SUNDAY. AN UPPER LEVEL DISTURBANCE WILL MOVE
ACROSS THE STATE FROM THE WEST SUNDAY... BUT IT WILL REMAIN
MOISTURE STARVED.
&&
.NEAR TERM /THROUGH TODAY/...
...CONSIDERING A DENSE FOG ADVISORY FOR PORTIONS OF THE WESTERN
PIEDMONT... MAINLY SW OF THE PIEDMONT TRIAD REGION MORNING...
OTHERWISE SLOW CLEARING OF LOW STRATUS AND FOG EXPECTED LATE MORNING
INTO THE EARLY AFTERNOON...
...RADAR TRENDS INDICATE NOTHING MORE THAN SPRINKLES FOR OUR SE
COUNTIES THROUGH DAYBREAK...
AS OF 245 AM SATURDAY... THE CURRENT HYBRID COLD AIR DAMMING
EPISODE IS EXPECTED TO LINGER WELL INTO THE LATE MORNING HOURS.
THE LINGERING LOW STATUS AND FOG WILL BE VERY SLOW TO SCOUR OUT
THIS MORNING AS MODELS INDICATE LIGHT WINDS IN THE BOUNDARY LAYER
INTO THE LATE MORNING. CURRENT SURFACE OBS INDICTED CEILINGS AND
VISIBILITIES WERE REMAINING STATUS QUO... EXCEPT FOR LOWERING SOME
OVER DAVIDSON... RANDOLPH... AND STANLY COUNTIES... WHERE WIDESPREAD
VSBYS OF 1/2 TO 1 MILE WERE OBSERVED. WE WILL MONITOR THESE AREAS
CLOSELY. HOWEVER... THE VISIBILITIES ARE EXPECTED TO REMAIN JUST
ABOVE THE THRESHOLD FOR A DENSE FOG ADVISORY.
THE 00Z/NAM WAS THE QUICKEST IN BEGINNING THE CLEARING IN THE LEE OF
THE APPALACHIANS BY MID TO LATE MORNING... WITH THE GFS INDICATING
THE CLEARING WILL BEGIN 3-4 HOURS LATER. GIVEN THE 00Z MODELS LACK
OF ABILITY TO INITIALIZE THE SATURATED BOUNDARY LAYER OVER THE
PIEDMONT DAMMING REGION...AND THE STRENGTH/DEPTH OF THE CAD (3-5K
FEET) BASED ON GSO/RNK 00Z/23 SOUNDINGS... IT APPEARS REASONABLE TO
FAVOR THE SLOWER CLEARING INDICATED BY THE 00Z/GFS. THIS CLEARING
SHOULD GET GOING IN THE LEE OF THE BLUE RIDGE LATE MORNING AS THE
DRY WESTERLY FLOW INCREASES ALOFT WITH THE PASSAGE OF THE MID LEVEL
TROUGH. AS THIS TROUGH MOVES EAST THROUGH CENTRAL NC DURING THE
AFTERNOON... THE CLEARING WILL SPREAD EAST. THERE SHOULD CONTINUE TO
BE SCATTERED TO BROKEN STRATOCUMULUS AT 4-5K FEET EVEN AFTER THE
LOWER STRATUS CLEARS OUT. THUS... WE WILL CONTINUE THE CURRENT
CLOUDY FORECAST THIS MORNING... BECOMING PARTLY CLOUDY THIS
AFTERNOON. THE TEMPERATURES WILL BE HIGHLY DEPENDENT ON HOW MUCH SUN
DEVELOPS THIS AFTERNOON. THE PREVIOUS FORECAST (WHICH LOWERED HIGHS
FOR TODAY) APPEARS VERY REASONABLE. WE WILL CONTINUE THE CURRENT MAX
T FORECASTS INDICATING MID 50S NORTH CENTRAL TO LOWER 60S SE-S.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
AS OF 245 AM SATURDAY...IN THE WAKE OF THE COLD FRONTAL PASSAGE
THIS EVENING... THE SKIES WILL TEMPORARILY BECOME MOSTLY CLEAR
FOR MOST AREAS. THIS WILL BE FOLLOWED BY ANOTHER BOUT OF
STRATUS/STRATOCUMULUS LATER TONIGHT INTO SUNDAY. THIS WILL OCCUR
AS THE LOW LEVEL NE FLOW PULLS ATLANTIC MOISTURE BACK ACROSS OUR
REGION. WHILE MODELS WERE GENERALLY IN AGREEMENT THAT STRATOCUMULUS
WILL EVENTUALLY DEVELOP INTO OUR REGION... THE 00Z/GFS WAS MUCH
FASTER IN SATURATION THE LOW LEVELS ESPECIALLY IN THE EAST
OVERNIGHT... SPREADING WEST BY DAYBREAK. MOSTLY CLEAR OR PARTLY
CLOUDY SKIES EARLY TONIGHT WILL BECOME OVERCAST AGAIN OVERNIGHT.
WITH THIS INCREASINGLY CLOUDY PATTERN TONIGHT... THE WARMER MET
STATISTICAL GUIDANCE WAS PREFERRED OVER THE GFS MOS. LOWS SHOULD
REMAIN IN THE UPPER 30S TO LOWER 40S... INSTEAD OF THE COLDER
LOWER 30S FORECAST BY THE GFS MOS IN THE PIEDMONT.
WITH THE UPPER SHORTWAVE EXPECTED TO MOVE EAST ACROSS THE STATE
DURING THE DAY SUNDAY... THE LIFT AND ASSOCIATED CLOUDINESS ALOFT
WILL COMBINE WITH THE LOW LEVEL MOIST NE FLOW TO KEEP THE
TEMPERATURES ON THE CHILLY SIDE. MAX T`S SUNDAY SHOULD ONLY REACH
THE MID 40S NORTH TO MID 50S SOUTH. THIS UPPER SYSTEM WILL BE
MOISTURE STARVED WITH LITTLE TO NO GULF INFLOW... EXPECT ONLY A
CHANCE OF A FEW SPRINKLES. WE WILL ADVERTISE ONLY A SLIGHT CHANCE
POP FOR ANYTHING THAT MEASURES 0.01. OTHERWISE... ONLY A FEW TRACE
AMOUNTS ARE EXPECTED.
THE UPPER LEVEL DISTURBANCE IS FORECAST TO SHIFT EAST SUNDAY
EVENING AS WEAK HIGH PRESSURE BUILDS IN FROM THE NORTHEAST.
HOWEVER... THE FLOW AT THE SURFACE IS EXPECTED TO REMAIN WEAK...
INDICATING THAT THERE SHOULD STILL BE SOME RESIDUAL LOW LEVEL
MOISTURE AND CLOUDINESS TO DEAL WITH. WE WILL ADVERTISE SKIES TO
BECOME PARTLY CLOUDY AS SUBSIDENCE BEHIND THE DEPARTING SHORT WAVE
FAVORS CLEARING ALOFT. LOWS SHOULD STILL BE ABOVE CURRENT GUIDANCE
AS THE LOW LEVEL MOISTURE SHOULD REMAIN RELATIVE HIGH. EXPECT
MOSTLY MID TO UPPER 30S.
HEIGHTS ARE FORECAST TO RISE ALOFT MONDAY INTO EARLY TUESDAY
AHEAD OF THE NEXT SHORT WAVE TROUGH. THIS WILL BRING MILD TO WARM
TEMPERATURES BACK. THE TRENDS IN THE PAST FEW RUNS HAVE BEEN TO
SPEED UP THIS TROUGH AND THE ASSOCIATED COLD FRONTAL PASSAGE FOR
OUR REGION (NOW APPEARS TO BE DURING THE DAY TUESDAY). THE MAIN
SURFACE STORM TRACK WITH THIS TROUGH IS EXPECTED TO BE WEST TO
EAST THROUGH THE OHIO VALLEY INTO THE NORTHEAST. THE ONLY SHOT AT
SHOWERS FOR CENTRAL NC WILL BE WITH THE TRAILING COLD FRONT
EXPECTED TUESDAY.
SENSIBLE WEATHER MONDAY LOOKS TO BE DRY AND WARMER WITH HIGHS
RETURNING TO THE 60S. INCREASING CLOUDINESS MONDAY NIGHT WITH A
SLIGHT CHANCE OF SHOWERS TOWARD DAYBREAK (NW ONLY). LOWS WILL BE
MILD WITH THE SW FLOW AND INCREASING CLOUDS (MOSTLY MID TO UPPER
40S).
THE SURFACE COLD FRONT SHOULD MOVE THROUGH CENTRAL NC DURING THE
DAY TUESDAY. THE BEST CHANCE OF SIGNIFICANT SHOWERS WILL BE OVER
THE MOUNTAINS. WITH LIMITED DYNAMICS... AND LITTLE IN THE WAY OF
BOUNDARY LAYER INSTABILITY AS THE FRONT MOVES EAST THROUGH CENTRAL
NC... WE SHOULD ONLY SEE A BAND OF LIGHT SHOWERS. QPF WILL BE
FORECAST AT LESS THAN 0.25 OF AN INCH. HIGHS SHOULD STILL REACH
60-65.
STRONG CAA WILL BLOW ACROSS CENTRAL NC BEHIND THE COLD FRONT LATE
TUESDAY AND TUESDAY NIGHT. THE SKIES WILL CLEAR RATHER ABRUPTLY
AFTER THE FROPA WITH STRONG SUBSIDENCE AND DEEP NW FLOW INDICATED
TUESDAY NIGHT. LOWS WILL BE LOWERED INTO THE 25-30 RANGE PER
LATEST GUIDANCE.
&&
.LONG TERM /WEDNESDAY THROUGH FRIDAY/...
A TRANSIENT POSITIVE PNA PATTERN WILL DEVELOP MIDWEEK RESULTING IN A
LONGWAVE TROUGH AMPLIFYING OVER THE EASTERN PORTION OF THE COUNTRY.
THIS WILL BRING A RETURN OF BELOW NORMAL TEMPERATURES BY WEDNESDAY
AS CANADIAN HIGH PRESSURE BUILDS INTO THE REGION IN THE WAKE OF THE
PREVIOUS NIGHT`S FRONTAL PASSAGE. HIGHS WEDNESDAY SHOULD ONLY MAKE
IT INTO THE UPPER 40S NORTH TO LOWER 50S SOUTH... AND WILL STRUGGLE
TO MAKE IT OUT OF THE MID AND UPPER 40S ON THURSDAY. LOWS WED/THU
NIGHT WILL DIP INTO THE 20S ACROSS MOST OF THE CWA.
AN ALBERTA CLIPPER LOOKS POISED TO APPROACH FROM THE NORTHWEST ON
FRIDAY... SENDING ANOTHER WEAK FRONT THROUGH THE AREA FRIDAY NIGHT.
AS A WEAK SOUTHWEST FLOW DEVELOPS AHEAD OF THE FRONT... TEMPS ARE
APT TO MODERATE SOME DURING THE DAY ON FRIDAY. HIGHS SHOULD REBOUND
CLOSER TO NORMAL LEVELS IN THE LOW TO MID 50S. NO PRECIP IS EXPECTED
AHEAD OF THIS FRONT GIVEN THE DRY NW FLOW REGIME.
&&
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
AS OF 1230 AM SATURDAY...IFR CONDITIONS AND OFTEN LIFR CONDITIONS
DUE TO CEILINGS WILL BE IN PLACE OVERNIGHT BENEATH STRONG INVERSION
THAT WILL REMAIN AROUND 2K TO 3K FEET AT LEAST THROUGH 12Z.
ALTHOUGH A BIT TOO HIGH FOR LLWS...AIRCRAFT SHOULD NOTE THAT WINDS
NEAR THE INVERSION...ESPECIALLY TOWARD KFAY...COULD REACH AROUND
35KT FROM THE SOUTHWEST BETWEEN 09Z AND 12Z. GRADUAL IMPROVEMENT IN
CONDITIONS WILL TAKE PLACE SATURDAY...WITH VISIBILITIES EXPECTED TO
BECOME VFR SATURDAY MORNING AS THE WESTERLY SURFACE FLOW INCREASES...
FOLLOWED BY VFR CEILINGS MAINLY IN THE AFTERNOON IN THE
DEEP...WESTERLY FLOW AS NOTED ON GFS AND NAM BUFR SOUNDINGS.
LOW CEILINGS LIKELY WILL RETURN LATE SATURDAY NIGHT IN AMPLE
LOW-LEVEL MOISTURE AND A NORTHEAST SURFACE FLOW THAT DEVELOPS
SATURDAY NIGHT OVER CENTRAL NORTH CAROLINA BEHIND A COLD FRONT.
MAINLY MID-LEVEL CLOUDS AND SPRINKLES OR PATCHY LIGHT RAIN ARE
ANTICIPATED BY SUNDAY AFTERNOON WITH THE PASSAGE OF A MODERATE
MID-LEVEL SHORTWAVE. AFTERWARD...THE NEXT...BEST CHANCE FOR MVFR OR
EVEN IFR CONDITIONS WILL BE TUESDAY ALONG AND AHEAD OF A COLD FRONT
THAT WILL SWEEP ACROSS THE STATE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT/JFB
NEAR TERM...BADGETT/JFB
SHORT TERM...BADGETT
LONG TERM...JFB
AVIATION...JFB
AREA FORECAST DISCUSSION
NWS RALEIGH NC
1237 AM EST SAT FEB 23 2008
.SYNOPSIS...
COLD...MOIST AIR WILL LINGER OVER THE AREA FOR MUCH OF THE NIGHT...
AS A LOW PRESSURE SYSTEM PASSES TO THE SOUTH OF THE REGION AND OFF
THE COAST. ANOTHER WEAK LOW PRESSURE SYSTEM WILL DRIFT ACROSS THE
AREA EARLY SATURDAY...FOLLOWED BY A COLD FRONT SATURDAY EVENING.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 815 PM FRIDAY...COLD-AIR DAMMING CONTINUES OVER CENTRAL
NORTH CAROLINA...WITH LOW CLOUDS AND LIGHT FOG CONTINUING WITH A
BREAK IN THE RAINFALL. THE BREAK IN THE RAIN SHOULD CONTINUE FOR A
COUPLE OF MORE HOURS OR SO...WITH A FEW PATCHES OF DRIZZLE
POSSIBLE. WATER VAPOR IMAGERY SHOWED STRONG DRYING MOVING EAST
ACROSS THE GULF OF MEXICO...AND AHEAD OF THAT DRYING A WEAK
SHORTWAVE WAS APPARENTLY MOVING NORTHEAST TOWARD THE CAROLINAS.
THE RUC WAS HAVING DIFFICULTY RESOLVING THIS WAVE AND THE
ATTENDANT INCREASE IN RAIN ACROSS CENTRAL GEORGIA...WHILE THE 18Z
NAM AND GFS APPEARED TO BE MUCH CLOSER TO REALITY AND FORECAST A
MODEST MID-LEVEL WAVE MOVING ACROSS THE SOUTHEAST PART OF THE
STATE LATE TONIGHT. ALTHOUGH PLAN VIEW UVV IS WEAK ON BOTH THE NAM
AND THE GFS...MODERATE UPPER DIFFLUENCE IS FORECAST BY BOTH
BETWEEN 06Z AND 12Z ESPECIALLY SOUTHEAST ZONES WHERE THERE IS ALSO
DECENT FRONTOGENESIS IN THE 700-500MB LAYER. ALL OF THIS ACCOMPANIED
BY JET SUPPORT...WITH THE FRONT ENTRANCE REGION OF A 115KT 300MB
JET LATE...AND NOTICEABLE DIFFLUENCE ON WATER VAPOR IMAGERY HEADED
TOWARD CENTRAL NORTH CAROLINA...HAVE NUDGED THE NORTHERN EXTENT OF
LIKELY POPS TO MAINLY ALONG AND SOUTH OF A LINE FROM KMEB TO
KGSB...WHERE THE SREF HAS THE GREATEST CHANCES OF MEASURABLE RAIN
OVERNIGHT. EXCEPT FOR THE TRIAD...FARTHEST AWAY FROM THE LIFT AND
JET SUPPORT...LEFT SLIGHT CHANCES FOR RAIN. ELSEWHERE...INCREASED
THE CHANCES FOR RAIN BY ABOUT 10 PERCENT. WHATEVER RAIN FALLS
OVERNIGHT SHOULD NOT MEASURE MUCH AS THE SREF SHOWS THE CHANCES
FOR RAIN AT OR ABOVE A QUARTER INCH TO BE ESSENTIALLY ZERO.
TEMPERATURES WILL REMAIN NEARLY STEADY...THOUGH DO EXPECT SOME
WARM DEW POINT ADVECTION LATE TONIGHT WHICH WILL HELP TO BOOST
TEMPERATURES ON AVERAGE ABOUT A CATEGORY BY MORNING. AREAS OF FOG
WILL PERSIST PARTICULARLY ALONG AND NORTH OF U.S. 64 AND MOST
ESPECIALLY TOWARD THE VIRGINIA BORDER WHERE SURFACE TEMPERATURES
ARE COOLER. AT LEAST PATCHY FOG SHOULD PERSIST INTO EARLY SATURDAY
MORNING.
FORECAST SOUNDINGS SHOW A VERY GRADUAL DISSOLUTION OF THE LOW LEVEL
MOIST AND STABLE AIR SATURDAY. THIS SEEMS REASONABLE CONSIDERING
THE MID LEVEL FLOW REMAINS FROM THE SOUTHWEST UNTIL MID LEVEL TROUGH
AXIS PASSAGE LATE IN THE DAY...AND A LINGERING SURFACE TROUGH
EXTENDING FROM THE OFFSHORE LOW BACK INTO NC APPEARS LIKELY. HAVE
GONE WITH A SLOW TRANSITION FROM CLOUDY IN THE MORNING WITH
PATCHES OF DRIZZLE...TO PARTLY CLOUDY BY LATE IN THE AFTERNOON. A
FEW SPRINKLES COULD OCCUR WITH THE MID LEVEL TROUGH PASSAGE...BUT
LIFT IS OVERALL FAIRLY WEAK. DUE TO THE PERSISTENT CLOUDS...A FEW
DEGREES HAVE BEEN SHAVED OFF SATURDAY HIGHS...WHICH ARE EXPECTED
TO BE 56-64...IN LINE WITH THE RECENT LOWERING TREND OF GFS MOS
GUIDANCE NUMBERS. IF THE CLOUDS LINGER LONGER THAN EXPECTED...
EVEN THESE MAY BE A FEW DEGREES TOO HIGH.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
AS OF 245 PM FRIDAY...IN THE WAKE OF THE COLD FRONT TEMPERATURES
SUNDAY WILL BE SIGNIFICANTLY COOLER THAN SATURDAY AND WITH THE
UPPER SHORTWAVE MOVING EAST ACROSS THE AREA ALONG WITH SOME MID
LEVEL MOISTURE EXPECT THE MID AND HIGH CLOUDS TO HANG IN
THROUGHOUT THE DAY. HAVE LOWERED THE CHANCE OF RAIN SUNDAY TO A
SLIGHT CHANCE DUE TO THE LACK OF LOW LEVEL MOISTURE AND ZONAL
WESTERLY ABOVE 850 MB. SUNDAY NIGHT WILL BE THE COLDEST WITH THIS
NEXT FRONTAL PASSAGE AND THE AMOUNT OF CLOUD COVER AND HOW FAST
SKIES CLEAR WILL DETERMINE HOW COLD OVERNIGHT LOWS DROP BY MONDAY
MORNING. THE HIGH SETTLING IN OVERHEAD SUNDAY NIGHT AND MONDAY
MORNING WILL THE THE COLDEST NIGHTS WITH THIS NEXT AIRMASS WITH
LOWS IN THE LOW TO MID 30S. CLOUDS BREAK A LITTLE FOR MONDAY
ALLOWING FOR TEMPERATURES TO REBOUND A LITTLE AS THE FLOW BECOMES
MORE SOUTHERLY.
WEAK RETURN FLOW STARTS TO DEVELOP MONDAY AS THE SURFACE HIGH MOVES
OFFSHORE LATE IN THE DAY MONDAY AND A STRONG AREA OF LOW PRESSURE
MOVES INTO THE OHIO RIVER VALLEY. WITH PERIODS OF SUNSHINE EXPECTED
MONDAY HIGHS WILL WARM BACK TO AROUND 60. BY MONDAY NIGHT THE
SOUTHWESTERLY FLOW INCREASES AT 850 MB WHILE MID AND HIGH LEVEL
MOISTURE STREAMS IN FROM THE WEST. SOUTHWEST FLOW INCREASES TO 50KT
OFF THE SURFACE ON TUESDAY RESULTING IN SOME WINDY CONDITIONS AND
ENOUGH LOW LEVEL MOISTURE TO PROVIDE SCATTERED SHOWERS AHEAD AND
ALONG THE COLD FROM WHICH WILL MOVE THROUGH THE AREA MID TO LATE
TUESDAY AFTERNOON. RIGHT NOW INSTABILITY LOOKS LIMITED AND AS
WITH PAST SYSTEM AND MOST OF THE DYNAMICS PASS TO OUR NORTH
HOWEVER THE WIND FIELDS ARE IMPRESSIVE. EITHER WAY IT LOOKS AS
THOUGH THE AREA WILL SEE A DECENT CHANCE OF RAIN TUESDAY, BUT
OVERALL RAINFALL AMOUNTS DUE NOT LOOK IMPRESSIVE DUE TO THE FAST
MOVING NATURE OF THE SYSTEM AND RELATIVELY SHORT DURATION OF
RAINFALL.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 245 PM FRIDAY...BELOW NORMAL TEMPERATURES AND DRY CONDITIONS
EXPECTED FOR THE MIDDLE AND END OF NEXT WEEK. AFTER A QUICK SHOT
OF RAIN TUESDAY CONDITIONS DRY OUT QUICKLY BY WEDNESDAY AS VERY
COLD AIR SURGES SOUTH WEDNESDAY AFTERNOON AND INTO THURSDAY. A
RETURN TO LOWS IN THE 20S IS AROUND THE CORNER WEDNESDAY NIGHT AND
THURSDAY NIGHT. CONDITIONS WILL LIKELY BE A BIT BREEZY WEDNESDAY
AFTERNOON AS THE DRY COLD AIR SURGES SOUTH. WINDS SHOULD BE A
LITTLE LIGHTER SOME THURSDAY AFTERNOON. MODELS SUGGEST A FAST
MOVING CLIPPER SYSTEM WILL APPROACH FROM THE WEST LATE FRIDAY AND
THIS COULD RESULT IN AN INCREASE IN THE MID AND HIGH CLOUDS BUT NO
REAL CHANCE OF RAIN.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 1230 AM SATURDAY...IFR CONDITIONS AND OFTEN LIFR CONDITIONS
DUE TO CEILINGS WILL BE IN PLACE OVERNIGHT BENEATH STRONG INVERSION
THAT WILL REMAIN AROUND 2K TO 3K FEET AT LEAST THROUGH 12Z.
ALTHOUGH A BIT TOO HIGH FOR LLWS...AIRCRAFT SHOULD NOTE THAT WINDS
NEAR THE INVERSION...ESPECIALLY TOWARD KFAY...COULD REACH AROUND
35KT FROM THE SOUTHWEST BETWEEN 09Z AND 12Z. GRADUAL IMPROVEMENT IN
CONDITIONS WILL TAKE PLACE SATURDAY...WITH VISIBILITIES EXPECTED TO
BECOME VFR SATURDAY MORNING AS THE WESTERLY SURFACE FLOW INCREASES...
FOLLOWED BY VFR CEILINGS MAINLY IN THE AFTERNOON IN THE
DEEP...WESTERLY FLOW AS NOTED ON GFS AND NAM BUFR SOUNDINGS.
LOW CEILINGS LIKELY WILL RETURN LATE SATURDAY NIGHT IN AMPLE
LOW-LEVEL MOISTURE AND A NORTHEAST SURFACE FLOW THAT DEVELOPS
SATURDAY NIGHT OVER CENTRAL NORTH CAROLINA BEHIND A COLD FRONT.
MAINLY MID-LEVEL CLOUDS AND SPRINKLES OR PATCHY LIGHT RAIN ARE
ANTICIPATED BY SUNDAY AFTERNOON WITH THE PASSAGE OF A MODERATE
MID-LEVEL SHORTWAVE. AFTERWARD...THE NEXT...BEST CHANCE FOR MVFR OR
EVEN IFR CONDITIONS WILL BE TUESDAY ALONG AND AHEAD OF A COLD FRONT
THAT WILL SWEEP ACROSS THE STATE.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DJF
NEAR TERM...DJF/HARTFIELD
SHORT TERM...JO
LONG TERM...JO
AVIATION...DJF/JFB
AREA FORECAST DISCUSSION...UPDATED
NWS MORRISTOWN TN
913 AM EST SAT FEB 23 2008
.DISCUSSION...
ACARS SOUNDINGS THIS MORNING FROM TRI INDICATE A DEEP SATURDATED
LAYER FROM THE SURFACE TO NEARLY 700 MB. 12Z OHX SOUNDING SHOWS A
STRONG INVERSION AND A SATURATED LAYER FROM AROUND 900 TO 800 MB.
SURFACE TEMPS TO OUR WEST ARE ALSO 10-15 DEGREES COOLER THAN
CURRENT TEMPS IN THE VALLEY. THIS INDICATES THAT THE SURFACE FRONT
IS CURRENTLY MOVING THROUGH THE AREA...AND THAT TEMPERATURES WILL
NOT RISE MUCH TODAY. A STRENGTHENING INVERSION WILL REDUCE THE
POTENTIAL FOR MIXING OUT OF CLOUDS...AND WTIH LIGHT WINDS SHIFTING
TO A MORE NORTHERLY COMPONENT...DOWNSLOPE FLOW OFF THE PLATEAU WILL
LIKELY NOT HELP TO ERODE THE LOW CLOUDS. THE UPDATE THIS MORNING
WILL INCREASE CLOUD COVER AND LOWER MAX TEMPERATURES...AS GFS MOS
APPEARS TO BE BREAKING OUT THE CLOUDS TOO QUICKLY.
THE DENSE FOG ADVISORY FOR SW NC WILL BE ALLOWED TO EXPIRE AT 10
AM.
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
DGS
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1007 AM CST SAT FEB 23 2008
.DISCUSSION...
SUB 1K FT EARLY MORNING STRATUS DECK BEGINNING TO ERODE ACROSS
OUR CENTRAL COUNTIES AT THE END OF THE 16Z HOUR. ACARS AND LCH
SOUNDING DATA PAINT A CLEAR PICTURE OF STRONG 950-900MB CAPPING
WITH SIGNIFICANT DRY AIR RIGHT OFF THE SURFACE. THIS DRY AIR WILL
MIX OUT THE REMAINDER OF THIS DECK QUITE NICELY THROUGH 17Z AS
SUNSHINE MAKES IT TO THE SURFACE. EXTRAPOLATING DOWN A DRY
ADIABAT FROM TOP OF INVERSION PRODUCES A SFC TEMP IN THE MID 70S.
TAKING THIS INTO CONSIDERATION...AND THE OFFSETTING FACT OF A SLOW
START TO WARMING PER THIS EARLY AM DECK...MAKES KEEPING MAX TEMPS
IN THE LOW 70S THE MOST LOGICAL CHOICE. MISSISSIPPI VALLEY SURFACE
HIGH EXPANDING SOUTHWARD OVER EAST TEXAS THIS MORNING WILL CONTINUE
UPON ITS EASTWARD TREK...TRANSLATING TO MORE OF A SOUTHEASTERLY WIND
BY MID-AFTERNOON. STILL EXPECTING A VERY WEAK AND DRY BOUNDARY TO
MAKE IT INTO THE NORTHERN COUNTIES THIS TIME TOMORROW...PRIMARY A
SUBTLE NORTHERLY WIND SHIFTER. 31
&&
.PREV DISCUSSION... /ISSUED 328 AM CST SAT FEB 23 2008/
DISCUSSION...
STRATUS DECK HAS PUSHED BACK WEST INTO THE FAR ERN ZONES EARLY
THIS MORNING. THE CLOUD COVER WILL LINGER FOR A FEW HOURS.
WESTERLY FLOW IN THE 850 MB LAYER WHICH SHOULD ALLOW THESE CLOUDS TO
MIX OUT BY MID-LATE MORNING. OTHERWISE...LOOKS LIKE A GREAT DAY
WITH PLENTY OF SUNSHINE AND LIGHT WINDS. HAVE LOWERED MAX TEMPS A
FEW DEGREES GIVEN THE VERY COOL START THIS MORNING. SFC RIDGE WILL
MOVE EAST OF THE AREA ALLOWING ONSHORE WINDS TO RETURN THIS AFTN.
CLEAR SKIES...LIGHT WINDS...AND GRADUAL RETURN OF LOW LEVEL
MOISTURE WILL FAVOR RADIATIONAL FOG DEVELOPMENT ACROSS MUCH OF THE
AREA LATE TONIGHT/EARLY SUNDAY. HAVE PLACED DENSE FOG OVER THE
COASTAL/SW ZONES WHERE CONFIDENCE IS HIGHEST. SUNDAY`S WEATHER IS
LOOKING GREAT AS WELL. THE WEAK COLD FRONT IS NOW FORECAST TO
STALL OVER OUR NRN ZONES AND HAVE LITTLE EFFECT ON OUR WEATHER.
HAVE BUMPED UP MAX TEMPS INTO THE UPPER 70S/NEAR 80 FOR INLAND
AREAS. SFC DEWPOINTS FORECAST TO REACH THE MID 60S ALONG THE COAST
BY SUNDAY EVENING. LOOKS LIKE SEA FOG WILL BEGIN DEVELOPING OVER
THE BAYS/NEARSHORE WATERS SUNDAY EVENING...ADVECTING INLAND AS FOG
OR A VERY LOW STRATUS DECK. FOG SHOULD BURN OFF MID MORNING MONDAY
FOLLOWED BY PARTLY CLOUDY SKIES AND INCREASING SOUTHERLY WINDS AS
LOW PRESSURE DEEPENS OVER THE PLAINS. 850 MB TEMPS FORECAST TO
INCREASE TO AROUND 20C MON AFTN...AND HAVE BUMPED TEMPS UPWARD.
LONGWAVE TROUGH CARVES OUT OVER MS VALLEY LATE MONDAY PUSHING A
STRONG COLD FRONT THROUGH SE TX MONDAY NIGHT. GFS BUFR SOUNDINGS
SHOW FAIRLY IMPRESSIVE SHEAR/INSTABILITY OVER OUR NRN ZONES
BEGINNING LATE MONDAY. HAVE INTRODUCED SOME LOW POPS FOR NE ZONES
BEGINNING MON AFTN. THE STRONG CAPPING AT 850 MB LEVEL WILL BE A
MAJOR LIMITING FACTOR IN CONVECTIVE DEVELOPMENT. THINK FORCING
WILL EVENTUALLY OVERCOME CAPPING AND ALLOW A THIN BAND OF
SHRA/TSRA TO DEVELOP ALONG/JUST BEHIND FRONT AS IT CROSSES THE
AREA. FRONT SHOULD PUSH OFF THE COAST BY 12Z TUESDAY. MID LEVEL
CLOUDINESS WILL LINGER FOR A FEW HOURS WITH CLEARING...COOLER...
BREEZY CONDITIONS TUE AFTN. WED MORNING LOOKS LIKE THE COLDEST
MORNING. IF THE WINDS DIE DOWN ENOUGH THEN WE COULD SEE A LIGHT
FREEZE IN SOME RURAL NORTHERN AREAS. ONSHORE FLOW RETURNS WED
NIGHT/THURSDAY RESULTING IN A GRADUAL WARMUP AND SOME LOW
CLOUDINESS SPREADING INTO THE AREA. GFS/ECMWF DIFFER AT THE END OF
THE WEEK...WITH GFS MORE AGGRESSIVE WITH MOISTURE RETURN/PRECIP
POTENTIAL. HAVE GONE WITH MOSTLY CLOUDY SKIES BUT KEPT POPS LOW.
35
&&
MARINE...
NORTHEAST FLOW ACROSS WATERS BECOMING EASTERLY AS THE DAY PROGRESSES.
HIGH PRESSURE RIDGE SHIFTING EAST OF REGION. THIS WILL RESULT IN THE
FLOW BECOMING MORE SOUTHEAST BY TONIGHT. THIS FLOW WILL STRENGTHEN
LATER MONDAY DUE TO TIGHTENING PRESSURE GRADIENT. WAVE HEIGHTS
WILL INCREASE LATE MONDAY ESPECIALLY OFFSHORE REGION. IF GFS IS
CORRECT UPPER TEXAS COASTAL WATERS SHOULD SEE SCA FLAG LATE MONDAY.
A STRONG COLD FRONT WILL MOVE ACROSS THE REGION LATE MONDAY NIGHT
AND EARLY TUESDAY MORNING. THIS FRONT WILL USHER A VIGOROUS OFFSHORE
FLOW PROBABLY 20-30 KTS TUESDAY. 37
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 71 53 79 58 83 / 0 0 0 0 10
HOUSTON (IAH) 70 53 79 58 82 / 0 0 0 0 10
GALVESTON (GLS) 65 59 72 62 74 / 0 0 0 0 10
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
DISCUSSION...31
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