Morning NWS Discussions
Posted by
JAC on 1/24/2011, 7:37 am
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TAUNTON MA 437 AM EST MON JAN 24 2011
WHAT IS CERTAIN IS A CLOSED LOW SYS IN THE NERN GULF 0Z WED WILL SIMULTANEOUSLY DEEPEN AND LIFT NWD INTO THE OUTER BANKS BY 18Z WED AND ACRS THE BENCHMARK AROUND 6Z THURS. THE COMBINATION OF STRONG UPR LVL DIV AIDED BY A COUPLING OF LEFT EXIT/RIGHT ENTRANCE RGNS OF H3 JET AXES...STRONG ISENTROPIC LIFT OF WARM AND MOIST AIR...COUPLED SFC AND UPR LVL JET AXES LENDING TO STRONG AGEO VERTICAL CIRC...AND CONSEQUENTIAL TROWAL STRUCTURE PARENTED WITH MID-LVL FRONTOGENESIS SHOULD LEND TO A VERY IMPRESSIVE AND DEEP COASTAL STORM SYSTEM. IT IS EXPECTED THAT AN INITIAL STRATIFORM PRECIP SHIELD WILL OVERSPREAD THE RGN WITH A LATER AREA OF FAVORABLE HEAVIER PRECIP DVLPMNT ALONG THE NW QUADRANT OF THE ATTENDANT SFC LOW AS IT PASSES SOUTH OF THE NEW ENG COASTLINE. LATEST TRENDS HIGHLIGHT THIS AREA OF HEAVIER PRECIP DVLPMNT TO COME ASHORE BUT TO REMAIN MORESO IN THE WARM SECTOR OF THE STORM.
SOME FINAL CONCERNS FOCUS UPON THE FACT OF HOW DEEP THIS SYS WILL BECOME RESULTING IN VERY STRONG AND GUSTY WINDS...ESPECIALLY FOR MARINE AREAS. THERE IS SOME FORETHOUGH TO THE POSSIBILITY FOR COASTAL FLOODING...BUT WILL FOCUS ON THIS DETAIL AS A BETTER HANDLE ON THE FCST IS OBTAINED.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 630 AM EST MON JAN 24 2011
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... MEDIUM RANGE MODEL GUIDANCE IS COMING INTO FOCUS RE THE COASTAL STORM PROGGED TO IMPACT THE AREA TUE NIGHT INTO THU...AS A VIGOROUS SRN STREAM SHORTWAVE TRAVERSING THE DEEP SOUTH BECOMES NEGATIVELY TILTED AND MOVES NE UP THE SOUTHEAST AND MID ATLANTIC COASTS. USED A BLEND OF THE 00Z GFS AND 23/12Z ECWMF FOR THIS FORECAST...WITH ASSOCIATED PRIMARY SFC LOW PRESSURE ALONG THE NE GULF COAST REDEVELOPING ALONG A LOW LEVEL BAROCLINIC ZONE ALONG THE CAROLINA COASTS TUE NIGHT INTO WED...THEN MOVING OFF THE SRN MID ATLANTIC COAST WED NIGHT AND PASS JUST SE OF LONG ISLAND LATE WED NIGHT INTO EARLY THU MORNING.
PRECIP SHOULD BEGIN LATE TUE NIGHT OR EARLY WED MORNING...BEGINNING AS SNOW...BUT THEN TRANSITIONING TO PRIMARILY RAIN AT THE COAST AND A WINTRY MIX INLAND AS WARMER AIR STARTS TO WORK IN ALOFT...WITH TOP DOWN PARTIAL THICKNESS P-TYPE ALGORITHMS IN GENERAL AGREEMENT. ANY ACCUMULATIONS DURING THE DAY ON WED LOOK TO BE MINOR AND CONFINED MORE TO THE INTERIOR...ESPECIALLY THE HIGHER ELEVATIONS.
THE HEAVIEST PRECIP SHOULD OCCUR WED NIGHT...MAINLY VIA STRONG ISENTROPIC LIFT ACROSS EASTERN SECTIONS AS A 50-60 KT EASTERLY LLJ OVERRIDES A WARM FRONTAL BOUNDARY EXTENDING NE FROM THE SFC LOW TOWARD CAPE COD AND THE ISLANDS...AND VIA FRONTOGENETICALLY FORCED BANDING ACROSS WESTERN SECTIONS WELL NW OF THE SFC LOW. MEANWHILE...LOW LEVEL FLOW SHOULD STRENGTHEN AND BACK NE-N AS THE SFC LOW APPROACHES...WITH SFC TEMPS DROPPING BELOW FREEZING AND ALLOWING PRECIP TO TRANSITION BACK TO SNOW...WITH AT LEAST A TRANSITIONAL PERIOD OF FREEZING RAIN POSSIBLE ACROSS MOST OF THE INTERIOR. THIS PERIOD OF ICING COULD BE MORE PROLONGED ACROSS SE CT AS THE AFOREMENTIONED LLJ CONTINUES TO TRANSPORT WARMER AIR IN ALOFT FOR A GOOD PART OF WED NIGHT.
WHEN ALL IS SAID/DONE...THERE IS GOOD POTENTIAL FOR SIGNIFICANT SNOWFALL ACROSS MUCH OF THE INTERIOR...AND SIGNIFICANT ICING FOR SOUTHEAST CT. LESSER SNOWFALL AMOUNTS ARE MORE LIKELY FOR NYC AND LONG ISLAND...BUT IT WOULD NOT TAKE MUCH DEVIATION FROM THE ABOVE SCENARIO TO BRING MORE SIGNIFICANT SNOWFALL/ICING FARTHER SOUTH TO THESE AREAS AS WELL...AS HPC WWD FORECAST SUGGESTS.
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In this thread:
Thursday 1/27 System -
JAC,
1/24/2011, 7:32 am- Re: Thursday 1/27 System - Fred, 1/26/2011, 4:18 pm
- Re: Thursday 1/27 System - Fred, 1/26/2011, 9:11 am
- Freezing Line - JAC, 1/26/2011, 8:51 am
- RI this afternoon - JAC, 1/26/2011, 6:33 am
- Chris in Tampa... - Conclue, 1/25/2011, 6:44 pm
- NYC NWS forecasts explosive development - JAC, 1/25/2011, 1:45 pm
- Look at this thing tho.... - Conclue, 1/25/2011, 11:43 am
- Firing up over MS Delta - JAC, 1/25/2011, 6:46 am
- Looks like Fred is in the swath - JAC, 1/25/2011, 6:44 am
- Re: Thursday 1/27 System - Fred, 1/24/2011, 4:03 pm
- 12Z NAM & GFS - JAC, 1/24/2011, 12:55 pm
- 06Z NAM - JAC, 1/24/2011, 8:31 am
- Morning NWS Discussions - JAC, 1/24/2011, 7:37 am
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