RSS
Home
WEATHERAmerica Newsletter, Saturday, July 4, 2009 at 5:30 P.M. CT
Print
Email
RSS
Subscribe
TODAY'S FUN LINKS: 4Cast4You Weather Street: U.S. Weather
WEATHER HAZARDS (During The Next 24 Hours)
SEVERE WEATHER OUTLOOK
(potential for tornadoes, damaging winds, and large hail within the next 24 hours)
(potential for tornadoes, damaging winds, and large hail within the next 24 hours)
ISOLATED Severe Thunderstorms
(Microbursts, Large Hail, Isolated Tornadoes)
AB....SK....MT....ID....WY....NE Panhandle....CO....NM
ISOLATED Severe Thunderstorms
(Microbursts, Large Hail, Isolated Tornadoes)
N, C TX....S OK....S AR....N LA....MS....AL....GA....SC....NC....VA....WV....S OH
KY....TN
Some Thunderstorms May APPROACH Severe Limits
MO....IL....IA....WI....MI
Some Thunderstorms May APPROACH Severe Limits
S FL
HEAVY RAINFALL OUTLOOK
(potential for an inch or more total rainfall within the next 24 hours)
(potential for an inch or more total rainfall within the next 24 hours)
Scattered Locations In
N, C TX....S OK....S AR....N LA....MS....AL....GA....SC....NC....VA....WV....S OH
KY....TN
(QPF 1 - 3")
Isolated Locations In
AB....SK....MT....ID....WY....NE Panhandle....CO....NM
(QPF 1 - 2")
Isolated Locations In
S FL
(QPF 1 - 2")
EXCESSIVE HEAT OUTLOOK
(potential for maximum temperature to exceed 95 deg F within the next 24 hours)
Scattered Locations In
CA....C, E OR....NV....AZ....UT....S ID....S MT....WY....CO....NM....TX....OK....AR
TN....NC....SC....GA....FL....AL....MS....LA
SHORT RANGE OUTLOOK
(Through The Next 72 Hours)
Thunderstorms, We Got Thunderstorms.....
WTOC-TV
NOAA/NCEP
Except for California and the Desert Southwest, you will be hard pressed to find any locations in the U.S. and adjacent Canada that will not be visited by showers and thunderstorms during the near term. The first matter of importance is a frontal structure that progresses from the Midwest into the Deep South and Eastern Seaboard. This wave-laden thermal boundary will have plentiful moisture from the Gulf of Mexico to work with, resulting in heavy rain and thunder. Some of the rainfall may be stratiform in the Mid-Atlantic region on Sunday night and Monday morning, in association with the mesoscale low pressure centers riding along the front. Severe weather is possible, but most of the truly strong upper dynamics will be far away from the unstable regime over the southern tier states. The cold upper low (latest in a series of same) may bring mostly diurnal convection to the Great Lakes and northern Appalachia over the course of the next 72 hours.
....And A Cold Front Reaching The Gulf Coast?
Plymouth State University Weather Server
It is highly unusual for a cold front to reach the Gulf Coast in July, but the numerical models are in agreement on just such an event happening during the next few days. The temperature boundary will serve as a catalyst for showers and thunderstorms, a welcome development due to the ongoing dryness stretching from TX into GA and N FL. It seems likely that the long run of near-record heat in parts of the Lone Star State will come to an end, at least temporarily.
Strong Storm, Frontal Structure Target The Pacific Northwest
Environment Canada
GOES WEST imagery shows a potent storm and cold front below the Aleutian Islands (a position quite unusual for summer). The various numerical models are in unison on the idea that this system will race eastward, with impacts on BC, WA, and OR within 48 -72 hours. Strong convection is probable over the Interior of the Pacific Northwest on Monday and Tuesday, with a surge of much cooler air affecting the region following the rains.
MEDIUM RANGE OUTLOOK
(Four To Ten Days From Now)
Surge Of Hot Air Into The Midwest And Eastern Seaboard
Plymouth State University Weather Server
The same storm which will target the Pacific Northwest in the near term will track eastward along the Canadian border during the work week, reaching the Great Lakes by Friday. This motion will assist in creating strong warm advection from the Intermountain Region and Great Plains, with the Midwest and Eastern Seaboard seeing a brief (one or two days) period of high heat and humidity. Since the main ridge axis will never budge east of Kansas, it is very unlikely that a prolonged spell of hot weather will occur to the right of the Mississippi River.
....Followed By Yet Another Cool Air Intrusion
The heat ridge complex will strengthen and tend to retrogress by next weekend, so it is only a matter of time before another shortwave digs into the Midwest with a return to cooler air. An impulse in the polar westerlies will deepen rapidly, forming a highly unseasonable closed low over Ontario. This feature will essentially duplicate the trend of weather seen in the Great Lakes and Northeast since mid-May: semi-constant threat of showers and thunderstorms and temperatures about five degrees below seasonal normals.
EXTENDED PERIOD FORECAST
(Between Day 11 And Day 15)
Will The Heat Ridge Retrogress In Mid-July?
Penn State University Weather Server
NOAA
An ongoing (incorrect) bias with the numerical models over the past two months has been a tendency for too much retrogression of the mean heat 500MB heat ridge. Whereas the core heights of the subtropical high have roughly been located in the vicinity of the "Arklatex", time and time again the various outlooks have shown placement of the ridge center over the lower High Plains or even the Intermountain Region. This scenario has verified only once recently: currently, with the hottest part of the regime split over the Southwest and over Texas into Louisiana. I suspect that after a shift into the lower Front Range in the medium range, the ridge complex will drift a bit toward the east in the 11 - 15 day time frame. GFS and NAEFS model data supports this scenario, implying a run of hot temperatures once again for the lower Great Plains and much of the Old South between July 15 - 20.
Again, A Quiet Tropical Weather Pattern Worldwide
University Of Wisconsin/CIMSS
NOAA/NESDIS
Although some reports have stated that the formative El Nino episode is behind the lack of tropical cyclone development over the Northern Hemisphere, that is only true for the Atlantic Basin. The Orient can be either very active or marginal, while the central/eastern equatorial Pacific Ocean often shows extreme levels of development . The +ENSO signal is only one of the factors, with an unusual display of low-latitude westerlies and cold air pockets another issue acting to limit the organization of warm-core cyclogenesis. Close to the Americas, constant advection of the hot, dry, dusty Saharan air mass has put a lid on convection, eliminating ITCZ waves progressing from central Africa while also curtailing thunderstorms associated with TUTT signatures and rogue tropical waves. I do not see this pattern changing anytime soon. Remember that with a building warm SST signature between the Philippines and Galapagos Islands, upper level westerly flow and cold pooling will begin to exert an influence in August. That means we have perhaps a five week window for development of convective circulations that might affect the Caribbean Sea, Gulf of Mexico and Deep South. And with the narrow corridor of deep mean easterlies still displaced far to the south of the U.S., odds on seeing a named storm of any strength are dwindling daily.
Prepared by Meteorologist LARRY COSGROVE on
Saturday, July 4, 2009 at 5:30 P.M. CT
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 2009 by Larry Cosgrove
Saturday, July 4, 2009 at 5:30 P.M. CT
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 2009 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.
This publication may not be reproduced or redistributed in whole or in part without the expressed written consent of the author.
Related Articles:
Add a Comment
TODAY'S FUN LINKS: YouTube - Stormvideoman's Channel Model Analyses and Forecasts (Parallel GFS) WEATHER HAZARDS (During The Next 24 …
Discussion (Relevant Graphics Follow The Text) If I took the computer models at face value, I could say that we will have a nice snowstorm for …
