WEATHERAmerica Newsletter, Tuesday, December 27, 2005 at 2:10 A.M. ET
WEATHER...@aol.com
(Disclaimer And Copyright Statements At End Of The Discussion)
TODAY'S FUN LINKS:
C. G. Rossby Rossby
(Carl-Gustav Arvid) In
French
Rossby, or
atmospheric long waves
WEATHER SUMMARY THROUGH NEXT 72
HOURS
With a "split flow" 500MB longwave pattern in effect, it is unlikely that we will see any true weather extremes during the near term. I say this because the nature of the upper level wind and height fields is fairly contiguous, keeping disturbances moving while at the same time preventing high degrees of amplification. The system now moving through Atlantic Canada, for instance, is quite strong, but because of upstream elements will not be able to languish and provide a building mechanism for a blocking signature (so no 50/50 low forming this time....).
The higher velocity jet stream segment now reaching from the West Coast to the Rocky Mountains will aid in the development of a moderately strong low pressure center (hybrid type at 500MB) in the High Plains today. While communities from BC into the Bay Area of CA are deluged with heavy rain (high elevation snowfall) today and tomorrow, precipitation from TX into NE through tonight will be minimal. That changes on Wednesday, however, as a moisture fetch becomes established form the Gulf of Mexico. Thunderstorms are probable in the lower Mississippi Valley, and the atmosphere should be unstable enough to allow for severe weather in extreme E TX....LA....MS....AL....S TN....AR. Given the linear nature of the PVA that is predicted by the NWP schemes, frozen types will be limited; much of the Corn Belt will see nothing worse than periodic light rain and drizzle.
By Thursday, secondary cyclogenesis will get underway over SE VA. Despite the presence of a cold anticyclone in QC, the progression of relatively fast 250MB flow across the Ohio Valley and the Northeast insures that: a) the path of the surface low will be right along the coastline and b) snow and sleet chances will be relegated, again, to communities in SE ON....N, C NY....W MA....VT....NH....W, C ME....NB....S QC. Since the storm will be quite impressive by the time it affects New England and the Maritime Provinces on Thursday and Friday, ice and snowfall potential may vary from substantial to excessive. However, the major cities along the Interstate 95 corridor, from Portland ME to Richmond VA, miss out on winter weather once again.
Short-Range Numerical Weather
Prediction Models
(red dot
indicates preferred model)
______________________________________________________________________
RUC NAM GFS-5. DGEX EPS Maps
RGEM. SREF MM5 CRAS UKMET COAMPS
RAMS
National Centers for Environmental
Prediction Models
Texas A&M Weather
Interface
______________________________________________________________________
Online Weather Information Guides
AMS Glossary WW2010 Helper Section
Index
Weather Calculator
COMET Case Study Library on the WWW
Climate Normals For The
U.S.
Golden Gate Weather ENSO
Page
Weather Discussion
Forums
Eastern US Weather
Forums
CanadianWeather
Weather Information
Plotting/Mapping
Plymouth State Weather
Center
Dr. Bob
Hart's Coolwx.com
U.S. National Satellite Perspectives
Next-Generation Weather Satellite Demonstration
Project
Infrared Visible Vapor
Hawaii Infrared Hawaii Visible
Alaska Infrared Alaska Visible Alaska
Vapor
Canada Satellite
Perspectives
Environment Canada Satellite Image
Directory
Satellite Animations And
Multi-Channel Imagery
RAMSDIS ONLINE
NOAA Polar Satellite
Views Around North America
Quicklook Swaths
Browser
AVHRR Dynamic Tracking Windows
Milan Konecny's NOAA Satellite Views
Savannah-Weather.Com
NOAA HRPT Weather Satellite Images
National Radar
Summaries
National NEXRAD Summary
Environment Canada Radar
Summary
Numerical Model Temperature
Forecasts
Current NWS MOS Forecast
Products
Links To Current Weather Conditions
Around North
America And Worldwide
MesoNet Data
NWS Precipitation Analysis
Pages Current Weather Observations
Ocean Prediction Center - Unified Surface
Analysis
National Data Buoy
Center Near Real-Time Polar
Products
Solar, Lunar, Astronomy
Information
MeL: Space &
Astronomy
SpaceWeather.Com
Tonight's Sky Sky & Telescope Interactive Sky
Chart
Human Space Flight - NASA-TV Solar
Terrestrial Activity Report
Satellite-Derived Forecast Products
NOAA/NESDIS/ORA
Forecast Products
Near Real-Time Polar
Products
Upper Air Analyses
Around North America
Upper Air Data From University Of
Wyoming
Aviation Weather
Analyses And Forecasts
Soundings from Commercial
Airliners
Aviation Weather Center
(AWC)
ORA Projects Page
ADDS - Turbulence
Environment Canada Aviation
Products
National Soil
Moisture Levels
Palmer Index Map (For Soil Moisture)
Drought Monitor
Snow And Ice
Coverage
U.S. Recent Snowfall & Snowdepth
Maps SSD Snow Products
Page
___________________________________________________________________________
SEVERE WEATHER OUTLOOK
(potential for tornadoes, damaging
winds, and large hail within the next 24 hours)
HEAVY RAINFALL OUTLOOK
(potential for an inch or more
total rainfall within the next 24 hours)
(probable trajectory for midlatitude cyclones affecting populous sections of the United States and Canada)
______________________________________________________________________
AWC National Convective Weather Forecast Product
Oklahoma University Daily Real Time Analysis And Forecast System
Experimental 0-3 Hour Convective Weather Forecast Products
Collaborative Convective Forecast Product
Environment Canada Severe Weather Model
Severe Weather Watch Boxes
SPC Watch, Warning and Advisory Display
Local Weather Warnings
College Of DuPage Severe Weather Warnings Page
U.S. Station Weather Probability Forecasts
_____________________________________________________________
READY - State Weather
NAM MOS Graphics NGM MOS Graphics
Form For Selecting AVN MOS Bulletins NAM Precip Type Meteograms
______________________________________________________________________
Visible, Infrared, And Water Vapor
High Resolution Satellite And Radar Views:
University Of Washington Weather Graphics Loops
IPS Meteostar
Regional Radar Summaries
Northeast
Southeast
North Central
South Central
Northwest
Southwest
Useful
Television Station And Commercial
Doppler Radar Sites
WeatherMatrix Radar Supersite : TV
Radars
Doppler Radar Images From Government Sources
National Weather Service Doppler
Radars
Environment Canada Doppler
Radars
Experimental
Radar Images From The National Weather Service
National
Lightning Detection Map
StrikeStar US
Experimental Lightning Location
Network
Environment Canada Lightning
Map
Local Lightning Detection Sites
BARBADOS Worthing VIRGIN ISLANDS St. Croix
_____________________________________________________________
Media Resources, Online Mapping And Travel
Aids
Kevin Brewster Storm Spotting Frequencies
Page
TV Station Web Page
Directory Radio-Locator
National Traffic and Road Closure
Information
MapQuest Maporama Microsoft TerraServer Google Earth
The National Atlas of the United States of
America
Where On Earth - Latitude Longitude
Finder
Map-It - A GMT3 Map
Generator
MEDIUM RANGE OUTLOOK
(weather trends through the next
6 to 10 days)
If you are a
weather enthusiast, part of that community that searches the Internet for all
things atmospheric, by now you have heard about the demise of winter. Many have
emailed me with comments like "year of the Pacific Jet" and "La Nina means
mild". This, of course, after one three day period of moderation and the retreat
of the rain to snow transition into (gasp) the Great Lakes and interior
Northeast. Since some need to hear a message of hope (yes, after three
days....), consider this "Cosgrove Rules Of Order" for winter
forecasting:
1) Split flow configuration usually last only 6-10 days when an "El Nino" is not present
2) There is no true "La Nina" anomaly in effect over the Equatorial Pacific Ocean, just a cool patch of waters that may well moderate within the next three weeks
3) When all of the numerical models shift the Aleutian Low southward toward HI, vigorous +PNA ridging is soon to follow
4) A three day period does not determine the nature of the winter. If you want a clue as to how things evolve, look at the succession of images of the 500MB longwave pattern during December
Now on to more topical matters. Once the low slated to affect the eastern half of the nation between now and December 31 exits the picture, a weaker impulse ending the sequence should move through the Corn Belt and Northeast with modest amounts of rain and a touch of sleet or snow. This follow-up disturbance should merge with the larger system downstream to form a strong 500MB low that approximates, if only for a short duration, a Grand Banks vortex (or, to use a colloquial term, 50/50 low). This setup in turn allows for pooling of cold high pressure across Hudson Bay into QC, sending an IcA regime as far south as about 40 N Latitude. So during the first week of the new year, some sort of baroclinic zone will line up from the Ohio Valley into the Mid-Atlantic region.
At the same time all of the above is transpiring, the amplification of the eastern Pacific Ocean trough complex enables 500MB height rises in western Canada. A shortwave spun off from the main trough and storm will pass through CA and the Desert Southwest with locally heavy rain and snow, then reach the lower Great Plains around January 4-5. With the upper level flow becoming more contorted and stronger high pressure over much of our northern neighbor, the emerging low looks to take a track through the Tennessee Valley and then off of Cape Hatteras NC before recurving northward to establish a newer, truer closed low aloft near NL/NWF. And since cold air may drain and wedge southward from QC, the chance is there for a significant winter storm from VA into the Maritime Provinces.
Now if all of that happens, you have to promise me that NOBODY will start spreading rumors of "the second coming of Superstorm 93"!!!!
Medium Range Numerical Weather Prediction
Models
(red dot indicates preferred model)
______________________________________________________________________
GFS. UKMETx ECMWF NOGAPS GGEM. MM5x KMA DAVA RSM JMA CPTEC GBL Ensembles
NCEP AVN-GFS Ensembles NOGAPS Ensembles WRF Hemispheric
Medium Range NWP Verification
Statistics
______________________________________________________________________
Worldwide and International Satellite
Images
Earth Viewer: View Any Location from Any
Satellite
______________________________________________________
GOES 12 (The
Americas, Atlantic Ocean)
Visible Infrared Vapor
______________________________________________________
GOES 10 (Eastern
Pacific Ocean)
Visible Infrared Vapor
______________________________________________________
GMS 5 (Asia,
Australia, Pacific Ocean)
Visible Infrared Vapor
______________________________________________________
METEOSAT 5
(Central Asia)
Visible Infrared Vapor
______________________________________________________
METEOSAT 7
(Europe And Africa)
Visible Infrared Vapor
______________________________________________________
Arctic Sea
Europe Infrared Europe Visible Europe Vapor
Russia The Middle East The Orient India
Australia New Zealand South America Africa
Antarctica
______________________________________________________________________
International Weather Radar Sites
WeatherMatrix Radar Supersite : World Radar
Data
Domestic And
International Weather Cameras
EarthCam
- Webcam Network
Satellite Images Of Individual Tropical
Systems
NRL Monterey Tropical Cyclone
Page
QuikSCAT
Satellite Images Of
Tropical Regions
GHCC - Interactive GOES-8 Infrared Hurricane
Sector
Atlantic Basin Satellite Services Division - Tropical Atlantic Satellite
Imagery
Mexico And Pacific Coastal
Waters
Central Pacific Ocean
Oceania And Tropical Western Pacific
Ocean
Indian Ocean
Digital Typhoon:
Typhoon Images and Information
Sea
Surface Temperatures
NODC Coastal Water Temperature
Guide
Great
Lakes Sea Grant Coastwatch Homepage
NCODA Sea Surface
Temperatures
NCODA Sea Surface Temperature
Anomaly
NCODA Sea Surface Temperature
Climatology
Marine Weather
Information
WWW Tide/Current Predictor - Site
Selection
Office of Coast Survey - Home - Nautical
Charts
Regional Ocean Forecast System
(ROFS)
NOAA/NCEP WAM Global Swell
Data
Environment Canada Ocean Wave
Forecasts
NOAA WAVEWATCH III Wave Models
(interactive)
Great Lakes Water
Levels
Prepared by Meteorologist LARRY COSGROVE
on
Tuesday, December 27, 2005 at 2:10 A.M.
ET
Disclaimer:
The previous statements are my opinions only, and should not be
construed as definitive fact. Links provided on this newsletter are not
affiliated with WEATHERAmerica and the publisher is
not responsible for content posted or associated with those
sites.
Copyright 2005 by Larry Cosgrove
All rights
reserved.
This publication may not be reproduced or redistributed in
whole or in part without the expressed written consent of the
author.