TODAY'S FUN LINKS:
Could a quiet sun cancel global warming? - Capital Weather Gang
World Trade Center classified as flood danger zone in new FEMA maps
Which drought-hit US states suffered the worst crop damage?
WEATHER HAZARDS (During The Next 24 Hours)
SEVERE WEATHER OUTLOOK
(potential for tornadoes, damaging winds, and large hail within the next 24 hours)
(Pressure Gradient Derived)
(Pressure Gradient Derived)
TX....E OK....W AR....W MO....E KS....E NE....W, C IA....W, C MN....C, E SD....ND
S MB....S SK....S AB....MT....NW WY....ID
HEAVY RAINFALL OUTLOOK
(potential for an inch or more total rainfall within the next 24 hours)
Isolated Locations In
S Coastal NL (Newfoundland)
(QPF 1 - 2")
WINTER WEATHER OUTLOOK
(potential for maximum temperatures below 25 deg F within the next 24 hours; snowfall in excess of 4 inches over a 24 hour period; or other frozen precipitation exceeding trace amounts)
(Snow; Blizzard; 4 - 16")
Scattered Locations In
N, C CA High Sierra....N, C NV....N UT....W CO....W WY....ID....MT....W, C ND....S SK
C, S AB....S BC....WA Coastal Ranges
(Snow; Mostly Above 4000 Feet; 4 - 24"; Sleet, Freezing Rain W, C ND)
GLOBAL WEATHER SUMMARY
(a review of important weather features around the world)
The incoherent nature of the Madden-Julian Oscillation, combined with the weakening and recession of the Arctic and polar westerlies into Siberia, point toward a warmer and largely drier trend from the Middle East through most of southern Asia. While Russia has a vast snowpack, and eastern sections of its commonwealth are quite cold, moderation will be setting in west of and eventually across the Ural Mountains by the 11 - 15 day period.
The MJO signal is strongest over the Southern Hemisphere below New Guinea and above Australia and New Zealand. That type of array almost always favors milder or warmer conditions over the northern half of the globe, with a progressive jet stream that may split in two. Note the total lack of connection between the equatorial convection and the intense winter storm over the Aleutian Islands. In a 500MB longwave pattern with true blocking, the moisture and energy link would line up close to the International Dateline into the gyre nearing Alaska.
There are two storms of great importance that are visible on the GOES WEST full disk image. The first will target the Midwest, Appalachia and Eastern Seaboard on March 5 - 7. I suspect that numerical model indications of intensity and track are underestimated largely because this feature has a deep tropical moisture fetch, and looks to be a bigger precipitation producer once it starts to tap the Gulf of Mexico moisture source (in effect doubling its dewpoint advection capacity). The second disturbance may have some cold weather impacts on California and the Southwest in the medium range, then could strengthen into a problematic severe weather producer from the lower/middle Great Plains through the Ohio Valley and Old South after March 10.
I suspect that the current GOES EAST imagery affords us a strong clue on how weather systems will play out over the next week or so. There is a huge, mostly untapped, subtropical jet stream covering the Gulf of Mexico and a diffuse, yet large, disturbance over Appalachia and the Carolinas. Note also the complete lack of ridging over Greenland (with a bump in the split flow over Quebec and Labrador). The storm threat of March 5 - 7 may pass just north of the location of the current low, since the once-forecast blocking signature is not present. If the impulse is stronger than the feature seen now in NC, then the broad field of high dewpoints and energy from the subtropical regions will phase into the later week system with higher, and more northward, outputs for precipitation in the Virginias, Mid-Atlantic and possibly the New England states.
The tropical regions of South America are still convectively active, with a wave over Colombia and Ecuador. Note the persistent broad heat ridge across the northern portions of Chile and Argentina into southern Brazil.
While the storm sequence from the northern Atlantic Ocean across Europe may seem ominous, in truth the active westerlies are pushing more moderate temperatures (mP as opposed to cA) through the subcontinent. Severe weather and heavy rainfall, however, will continue to be a problem for most of the Mediterranean countries, while an area from the British Isles through Germany, Scandinavia and the Baltic States has continued potential for stratiform rain and snow.
Both the Saharan and Kalahari heat ridge complexes are showing renewed strength. Equatorial convection is more sporadic, as evidenced by the lone ITCZ wave entering the Atlantic Ocean. A sign of spring is the northward expansion of this thunderstorm belt, now showing up from the Rift Valley into Eritrea and Somalia.
SHORT RANGE OUTLOOK
(Through The Next 72 Hours)
Strong Storm Advances From Gulf Of Alaska Into The Midwest; Snow, Wind Threats With Much Warmer Temperatures To South And East Of Storm Track
Plymouth State University Weather Server
University Of Wisconsin Weather Server (3)
The storm and moisture fetch off of the West Coast look to be big players in national weather during the next five days. Heavy rain and snow will be an issue across parts of the West on Sunday before the system undergoes lee cyclogenesis in southern Alberta on Monday. This feature is different from its predecessors in the western U.S. this winter, largely because the energy will not flatten a shortwave ridge across the Desert Southwest (which remains relatively mild and dry for now). Instead, the northern Great Plains and Midwest will feel the bite of this compacting feature through Tuesday.
A first inkling of future snow and ice issues will occur over Montana and the Dakotas by late Sunday. Frozen precipitation will expand in an east-southeast direction, following the upper level flow. Vorticity advection with the shortwave will expand (I suspect that a closed low will be embedded in the 500MB wind field by Monday morning), and a fairly narrow band of moderate to heavy snow should reach portions of MN, IA, WI, and IL later on March 4. Since the focus of this disturbance will be toward and into the Midwest, very little precipitation may fall south of the Missouri Valley. What will be noted is that warmer air should occupy areas south and east of the general storm track, enabling cities such as Houston and Dallas in TX to reach 80 degrees on Monday before the attendant cold front pushes through.
Cold Air Mass Across The Eastern Half Of U.S. Will Be Transient; Brief Moderation Likely By Midweek
Plymouth State University Weather Server
The much ballyhooed (in some meteorological circles) cold wave has turned out to be yet another transient cold spell across the eastern half of the nation. While still chilly (near or slightly below normal for March), most of the Old South will see nice moderation in temperature in passage through the warm sector of the storm mentioned in the previous paragraphs. That scenario will quickly change Tuesday night as the low pressure center strengthens and begins to draw a smaller patch of polar air through Dixie (although not in any way Arctic in nature; the split flow at 500MB features the cAk circumpolar vortex in Nunavut AR or the Northwest Territories).
Continued In Part 2....