Jump to content
  • Member Statistics

    17,600
    Total Members
    7,904
    Most Online
    ArlyDude
    Newest Member
    ArlyDude
    Joined

feb 28/march 1 rain storm


earthlight

Recommended Posts

  • Replies 92
  • Created
  • Last Reply

Cool link. The guidance this evening is ramping up the QPF and thunderstorm threat with the thermal boundary and cold front in the area. The NAM is actually keeping the low level jet slightly disjointed but it's gotten stronger the past few runs. Could be a pretty interesting event to nowcast.

Link to comment
Share on other sites

What kind of winds are we talking about with this? 60 mph again?

Probably not close to that unless there are some strong/severe thunderstorms...the system is weaker and the trough is pretty broad. The best winds may actually come with the CAA unless you're on eastern LI where the NAM has 20-25+kt southerly winds again at 10m.

Link to comment
Share on other sites

Slight Risk basically up to Staten Island and N NJ on the Day 2 outlook

day2probotlk_0700_any.gif

...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS LOWER-MID MS VALLEY TO

CAROLINAS/MID-ATLANTIC REGION...

...SYNOPSIS...

MID-UPPER LEVEL CYCLONE -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY

OVER SRN CA -- IS FCST TO DEVOLVE TO OPEN-WAVE TROUGH AND ASSUME STG

POSITIVE TILT DAY-1 AS IT ACCELERATES ENEWD ACROSS SRN PLAINS. BY

START OF PERIOD...500-MB TROUGH SHOULD EXTEND FROM MO SWWD ACROSS

N-CENTRAL TX. THOUGH MINOR/MESOSCALE DIFFERENCES EXIST IN

TIMING...STG CONSENSUS OF SREF AND OPERATIONAL PROGS INDICATES

TROUGH SHOULD DEAMPLIFY GRADUALLY AND MOVE OFFSHORE MID-ATLANTIC

COAST DURING 01/06Z-01/12Z TIME FRAME.

AT SFC...DOMINANT LOW BY 28/12Z SHOULD BE LOCATED OVER LE/WRN

NY/NWRN PA REGION...WITH SECONDARY/FRONTAL-WAVE LOW POSSIBLE OVER

SERN MO/SRN IL REGION ALONG TRAILING SFC COLD FRONT. FRONT SHOULD

EXTEND FROM THAT LOW SWWD TO NEAR MID/UPPER TX COAST. EXPECT MAIN

LOW TO MOVE ENEWD ACROSS NEW ENGLAND DURING LATE

AFTERNOON/EVENING...WITH 01/00Z COLD-FRONTAL POSITION NEAR

PVD...IAD...ATL...LAF LINE. FRONT WILL SWEEP OFFSHORE ALL BUT GA/FL

ATLANTIC COASTS BY END OF PERIOD...WHILE CROSSING FL PANHANDLE FROM

NE-SW.

...LOWER-MID MS VALLEY TO CAROLINAS/MID-ATLANTIC REGION...

SVR EVENT DISCUSSED IN DAY-1 OUTLOOK WILL BE ONGOING INTO THIS

PERIOD ACROSS WRN PORTIONS OUTLOOK AREA...AND MAY FAN OUT TO AFFECT

BROAD SWATH OF ERN STATES THROUGH AFTERNOON/EVENING. DAMAGING WIND

WILL BE MAIN THREAT...WITH AT LEAST A FEW TORNADOES POSSIBLE.

CORRIDOR OF GREATER RISK AND MORE ENHANCED PROBABILITIES IS POSSIBLE

WITHIN THIS SWATH...BUT TOO DEPENDENT ON MESOSCALE PROCESSES TO

NARROW DOWN SPECIFICALLY ATTM.

SFC ANALYSIS SHOWS 60S F SFC ISODROSOTHERM ALREADY INLAND TO RED

RIVER VALLEY REGION OF S-CENTRAL/SE OK AND N-CENTRAL/NE TX AS OF

27/05Z...WITH MID-60S CENTRAL TX AND COASTAL PLAIN. RELATED MOIST

PLUME IS FCST TO ADVECT NEWD ACROSS OZARKS AND LOWER-MID MS VALLEY

DAY-1...LEADING EDGE OF WHICH MAY BE SUPPORTING AT LEAST MRGL SVR

HAIL POTENTIAL IN TSTMS ROOTED ABOVE SFC OVER PORTIONS NRN

INDIANA/OH BY 28/12Z. FARTHER S ACROSS WARM SECTOR...MORNING

BOUNDARY LAYER WILL CONTAIN CHARACTERISTIC TEMPORAL MAX IN STATIC

STABILITY IN SHALLOW/NEAR-SFC LAYER. HOWEVER...THETAE ADVECTION

WILL HELP TO OFFSET THIS TENDENCY ENOUGH TO YIELD SVR THREAT FROM

QLCS AND/OR EMBEDDED SUPERCELL MODES. FCST MORNING SOUNDINGS SHOW

MAGNITUDE/DEPTH OF STABLE LAYER TOO SMALL TO PRECLUDE EFFECTIVE

LIFTED PARCELS FROM BEING SFC-BASED...OR VERY NEARLY SO. MAIN

UNCERTAINTIES FOR EARLY IN PERIOD INVOLVE WHETHER ANY

EMBEDDED/PRECURSORY SUPERCELLS WILL BE PRESENT IN ADDITION TO

DOMINANT LINEAR CONVECTIVE MODE...AND HOW FAR SWD INITIAL BAND OF

MAY BACKBUILD INTO MORE STRONGLY CAPPED...ELEVATED MIXED-LAYER AIR.

ADDITIONAL DEVELOPMENT AND/OR BACKBUILDING OF INITIAL/MORNING

ACTIVITY IS EXPECTED DURING DAY ACROSS PORTIONS TN VALLEY REGION AND

AL INTO SRN APPALACHIANS...WHILE ACTIVITY ALONG/AHEAD OF COLD FRONT

FARTHER N MOVES EWD-ENEWD UP OH VALLEY AND INTO CENTRAL

APPALACHIANS. BROAD AREA OF FAVORABLE DEEP-LAYER SHEAR IS EXPECTED

ACROSS AT LEAST MRGLLY UNSTABLE WARM SECTOR...WITH MID-UPPER FLOW

STRENGTHENING JUST AHEAD OF COLD FRONT AS SHORTWAVE TROUGH APCHS.

STRONGEST ISALLOBARIC FORCING WILL BE SHIFTING NEWD ACROSS ST.

LAWRENCE VALLEY AND NY/NEW ENGLAND...AHEAD OF WARM

SECTOR...RESULTING IN SWLY SFC WINDS OVER MOST OF OUTLOOK AREA.

HOWEVER...FCST SOUNDINGS SUGGEST SLGT VEERING WITH HEIGHT IN LOWEST

1-2 KM...COMBINED WITH STG SPEED SHEAR...WILL PRODUCE FAVORABLY

ENLARGED HODOGRAPHS FOR BOWS...AS WELL AS SUPERCELLS EITHER EMBEDDED

WITHIN OR AHEAD OF CONVECTIVE BANDS. BROAD SWATHS OF DAMAGING WIND

APPEAR QUITE POSSIBLE...HENCE LARGE SIZE OF AOA 30% SVR

PROBABILITIES.

INSTABILITY WILL BE WEAKER WITH NWD EXTENT...BUT WITH AT LEAST

NEUTRAL TO WEAKLY POSITIVE BUOYANCY AS FAR N AS OH/PA IN SUPPORT OF

SVR THREAT. SRN EXTENT OF ORGANIZED SVR POTENTIAL REMAINS RATHER

UNCERTAIN ATTM...THEREFORE PROBABILITIES ARE TAPERED SWD TOWARD GULF

AND SEWD TOWARD COASTAL CAROLINAS.

..EDWARDS.. 02/27/2011

Link to comment
Share on other sites

Probably not close to that unless there are some strong/severe thunderstorms...the system is weaker and the trough is pretty broad. The best winds may actually come with the CAA unless you're on eastern LI where the NAM has 20-25+kt southerly winds again at 10m.

Ok, so as far as I'm concerned......This storm blows ;)

Link to comment
Share on other sites

New Day 2 Outlook

day2probotlk_1730_any.gif

SPC AC 271730

DAY 2 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

1130 AM CST SUN FEB 27 2011

VALID 281200Z - 011200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS MUCH OF TN/KY AND

NORTHERN PORTIONS OF MS/AL/GA TO SOUTHERN WV AND WESTERN PORTIONS OF

VA/NC/SC...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE TN/OH VALLEYS AND

SOUTHEAST/MID-ATLANTIC STATES...

...SYNOPSIS...

UPPER LOW...CURRENTLY OPENING/ACCELERATING OVER AZ/NM AS OF SUNDAY

AFTERNOON...WILL CONTINUE TO ACCELERATE NORTHEASTWARD FROM THE

SOUTHERN PLAINS/LOWER MO VALLEY EARLY MONDAY TO THE NORTHEAST

STATES/MID-ATLANTIC SEABOARD BY MONDAY EVENING. AT THE SURFACE...THE

PRIMARY SURFACE LOW IS EXPECTED TO STEADILY ADVANCE NORTHEASTWARD

FROM THE UPPER OH VALLEY/LOWER GREAT LAKES TO NEW ENGLAND...WITH

SECONDARY SURFACE LOW DEVELOPMENT POSSIBLE TOWARD THE

APPALACHIANS/MID-ATLANTIC STATES AHEAD AN EASTWARD-ADVANCING PACIFIC

COLD FRONT/EARLY DAY CONVECTION. A POTENTIALLY WIDESPREAD SEVERE

EPISODE IS LIKELY ON MONDAY...INCLUDING THE POSSIBILITY OF

WIDESPREAD SWATHS OF DAMAGING WINDS IN ADDITION TO TORNADOES.

...TN VALLEY/LOWER OH VALLEY TO SOUTHEAST/MID-ATLANTIC STATES...

AN ONGOING DAMAGING WIND/TORNADO RISK IS PROBABLE ACROSS PORTIONS OF

THE TN VALLEY/LOWER OH VALLEY VICINITIES AT THE BEGINNING OF THE

PERIOD...REFERENCE DAY 1 OUTLOOKS FOR ADDITIONAL GUIDANCE. WITH

AROUND 60 F SURFACE DEWPOINTS ALREADY ESTABLISHED THIS AFTERNOON

ACROSS THE TN VALLEY...AND MIDDLE 60S F DEWPOINTS ALONG THE GULF

COAST...ROBUST NORTHEASTWARD MOISTURE TRANSPORT /AS AIDED BY 50-70

KT SOUTHWESTERLY WINDS AROUND 1-2 KM/ WILL CONTINUE TO OCCUR THROUGH

TONIGHT AND THE DAY ON MONDAY.

AT THE BEGINNING OF THE PERIOD...THE MOST PROBABLE SCENARIO WOULD

INCLUDES THE POSSIBILITY OF SEMI-DISCRETE SUPERCELLS AHEAD OF

INCREASINGLY LINEAR/QLCS-TYPE CONVECTION ROUGHLY ATTENDANT TO THE

EASTWARD ADVANCING PACIFIC FRONT...WHICH SHOULD BE NEARING THE MS

RIVER VICINITY EARLY IN THE MORNING. EVEN WITH AN UNFAVORABLE

CLIMATOLOGY TIME OF DAY /NEAR 12Z/...SURFACE BASED TSTMS SEEM

PROBABLE GIVEN THE DEGREE OF MOISTURE/TURBULENT MIXING...AS

SUPPORTED BY VARIOUS FORECAST SOUNDINGS...WITH CORRESPONDING

POTENTIAL FOR DAMAGING WIND AND EVEN STRONG TORNADO RISK ONGOING AT

THE BEGINNING OF THE PERIOD VIA QLCS/EMBEDDED SUPERCELLULAR MODES.

IN ADDITION...ALONG/NORTH OF THE SURFACE FRONTAL ZONE ACROSS THE OH

VALLEY/MIDWEST...AN EARLY DAY ELEVATED HAIL THREAT COULD EXIST AS

WELL.

SUBSEQUENT ADDITIONAL/BACKBUILDING TYPE DEVELOPMENT IS EXPECTED

THROUGH THE DAY ALONG/AHEAD OF THE COLD FRONT AS ACTIVITY

DEVELOPS/QUICKLY SPREADS EASTWARD TOWARD THE APPALACHIANS/SOUTHEAST

STATES. IN ALL...A BROAD AREA OF STRONG DEEP-LAYER FLOW/STRONG SPEED

SHEAR IS EXPECTED COINCIDENT WITH A SEASONALLY MOIST AND AT LEAST

MARGINALLY UNSTABLE WARM SECTOR. FAST-MOVING/WELL-ORGANIZED

QUASI-LINEAR/BOWING CONVECTION...IN ADDITION TO QUASI-DISCRETE OR

EMBEDDED SUPERCELLS...WILL SUPPORT THE POTENTIAL FOR WIDESPREAD

SWATHS OF DAMAGING WINDS AS WELL AS SOME TORNADOES.

..GUYER.. 02/27/2011

Link to comment
Share on other sites

Going to be most interesting tonight and tomorrow to see how the line evolves and just how much rainfall actually occurs. Does seem like some models are focusing the action a little further south.

Bullseye looks to be Philly to Central Jersey coast as of now, but we should still manage an inch plus. I'll probably get similar amounts to what I got with the last storm -- 1" to 1.50" with half the winds.

Link to comment
Share on other sites

a bit of a snippet from the blog discussion written by rob (dark energy on the forum)

http://www.nymetrowx.blogspot.com/

Short Term

Active day tomorrow with rain and scattered storms with heavy rainfall likely. With the warm front advancing N in the morning, we can expect our first round of precip. Then in the afternoon, there may be some partial clearing behind the warm fropa. This potentially could get us some weak instability. The guidance have under 500 j/kg of CAPE tmw but the mid level lapse rates in the afternoon will be strong. The LLJ moving in is on the order of 60-70 kts as the frontal wave passes by to our NW. The upper trof will approach in the late afternoon and attm, the right entrance region of the h3 jet will be over our area. Ahead of the front, we are in the warm sector and any breaks in the clouds should allow temps to get well into the 50s, if not mid 60s in some areas. A line of low-topped convection should form over PA and push into our region by late afternoon. There will be a stout inversion in the low levels during the day but that should mix out later on. The line of storms should be able to mix down the strong LLJ so we included strong winds in the forecast to cover this. SPC has parts of the area in a slight risk for svr tomorrow and this looks warranted. With PW around 1.3 inches, heavy rainfall is likely and this could cause flooding issues. The eve commute looks to have delays due to convection pulling thru. The cold front pulls east just after 0z. Before it does so, there will be some CAA and so we kept the mention of some light snow before the rain ends. Not expecting any accumulation due to the BL temps being too warm but the upper levels will be cooling quite a bit. Once the fropa takes place, gusty winds will commence. We should see gusts to 40 mph easily and this will last into the night. Skies clear out twds 5z with temps cooling off into the 20s and 30s twds morning.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...