Alert archive / Connecticut / Mesoscale Discussions in 2011
Mesoscale Discussion 21
The Storm Prediction Center issued this mesoscale discussion at Jan 12, 2011, 12:45 AM EST for 8 counties in Massachusetts; Suffolk County, New York; 5 counties in Rhode Island. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Jan 12, 2011, 12:45 AM EST (05:45 UTC)
- Expired
- Jan 12, 2011, 4:45 AM EST
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
Counties Bristol County, MA, Essex County, MA, Hampden County, MA, Middlesex County, MA, Norfolk County, MA, Plymouth County, MA, Suffolk County, MA, Worcester County, MA, Suffolk County, NY, Bristol County, RI, Kent County, RI, Newport County, RI, Providence County, RI, Washington County, RI
The radar
The Boston radar (KBOX), 64 km from the middle of the area, began a volume at 05:44 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The nearest sounding before it
Brookhaven, NY (KOKX), launched 00:00Z, 5.8 hours before the alert went out and 130 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1094 m above ground
- 0-6 km bulk shear
- 70 kt
- 0-1 km storm-relative helicity
- 186 m²/s²
- 0-3 km storm-relative helicity
- 260 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
991
ACUS11 KWNS 120546
SWOMCD
SPC MCD 120545
MAZ000-NHZ000-RIZ000-CTZ000-NYZ000-120945-
MESOSCALE DISCUSSION 0021
NWS STORM PREDICTION CENTER NORMAN OK
1145 PM CST TUE JAN 11 2011
AREAS AFFECTED...SRN NEW ENGLAND...LONG ISLAND NY
CONCERNING...HEAVY SNOW
VALID 120545Z - 120945Z
PRIMARY THREAT FOR HEAVY SNOWFALL WILL SHIFT NEWD INTO SRN NEW
ENGLAND. SNOWFALL RATES OF 1-2 IN/HR LIKELY.
SFC ANALYSIS AT 06Z REVEALED A RAPIDLY DEEPENING SFC LOW /AS MUCH AS
6 MB PER 2 HRS/ CURRENTLY POSITIONED S OF LONG ISLAND NY. THIS IS
OCCURRING AS VERY STRONG MID-LEVEL ASCENT OVERSPREADS THE REGION
AHEAD OF A VIGOROUS UPPER LOW AND ATTENDANT 140 KT UPPER JET. AS A
RESULT...A SWATH OF MODERATE TO HEAVY SNOWFALL HAS DEVELOPED ACROSS
MUCH OF THE NYC-PHI CORRIDOR. SFC LOW WILL CONTINUE TO DEEPEN AND IS
FORECAST TO TRACK NWD TO NEAR KBID BY 12Z. SNOWFALL IS EXPECTED TO
ORGANIZE INTO BANDS OVER THE NEXT SEVERAL HRS...WITH THE CORRIDOR
FROM ERN CT AND RI INTO ERN MASS THE FAVORED REGION FOR THE HEAVIEST
SNOWFALL. ENHANCED SNOWFALL RATES MAY DEVELOP AT TIMES FROM EMBEDDED
CONVECTIVE ELEMENTS WITH STEEP MID-LEVEL LAPSE RATES IN PLACE. WARM
AIR WRAPPING AHEAD OF THE SFC CYCLONE MAY FAVOR RAINFALL AS THE
PREDOMINANT P-TYPE IMMEDIATELY ALONG THE SERN COAST OF MASS. LATER
THIS MORNING...STRENGTHENING WINDS MAY YIELD NEAR-BLIZZARD
CONDITIONS WITH REDUCED VISIBILITIES ACROSS MUCH OF ERN
MASS...INCLUDING THE BOSTON METRO AREA.
..ROGERS.. 01/12/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...GYX...BOX...OKX...ALY...
LAT...LON 41517090 41027196 40777258 40687303 40747321 41147353
41707333 42187258 42647256 42787189 42847113 42667073
42247058 41987040 41777044 41517090SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jan 11, 8:00 PM EST | Mesoscale Discussion | SPC | 5 hr | |
| Jan 12, 6:27 AM EST | Mesoscale Discussion | SPC | 6 hr |
Nearby
Mesoscale Discussions in Connecticut, 2011Mesoscale Discussions in Massachusetts, 2011Mesoscale Discussions in Rhode Island, 2011Every mesoscale discussion in 2011
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.