http://hometown.aol.com/wxamerica/prof.index.html
His message is below..
Identifying Potential Weather Extremes In North America For Summer 2005
With the summer season fast approaching, we can identify some key concerns for energy production and consumption. Typical questions raised by corporations and the general public are:
1) How hot and humid will it be? And which region will be hottest?
2) Will the next few months feature drought, or perhaps severe weather with flooding?
3) Is this going to be an active hurricane season? Will we see anything like the unusual barrage of tropical cyclones which hit Florida last year?
4) Will the lingering weak El Nino play a role in the progression of features during the warm months?
Thermal and Dew Point Anomalies Through October 1
The emerging story of the spring has been the emergence of stable, moderate anticyclone over the Southeast. This ridge, while not quite reaching subtropical high status (that is core values exceeding 588dcm at 500MB), has lowered water profiles in a region which just one month ago was reeling from torrential rainfall and severe thunderstorms. While higher 500MB heights have relocated to the Sonoran position in recent days, the presence of strong storms entering the Intermountain Region from the Gulf of Alaska will eventually give rise to a subtropical high over Dixie. I usually identify positive height anomalies at lower latitudes in late spring, then apply latitude ascent, retrogression, and enhancement of the highest heights and thicknesses to approximate the summertime position of hottest readings. Extrapolation on the building and motion of the ridging places the likely July/August placement in the middle and lower Missouri Valley. In a "strength" phase, this might mean extensive heat into the Upper Midwest, Great Lakes, as well as the Ohio Valley and middle/lower Appalachia. In a weakened or collapsed scenario, the hottest values would end up from the middle/lower Great Plains through the Southeast. At this time, the "usual" (i.e. climatological) scenarios of a Sonoran ridge and Bermuda High appear to be missing from the summer 2005 profile.
If ridging does take on a dominant role in the center of the U.S., then the highest amount of dewpoint advection would shift from the Gulf of Mexico into the High Plains and Intermountain Region, then through the Upper Midwest and Great Lakes. Keep in mind that surface humidity can also be excessive directly under and to the left of the core of the expectant heat ridge. Under this line of reasoning, the Interstate 35 corridor (Laredo TX to Duluth MN) and adjacent markets can expect one miserable summer with little hope of cooling diurnal convection.
Precipitation And Convective Potential Over The Following 120 Days
If the strongest ridging does set up over the interior of the nation, then the potential for prolonged dry conditions will become anchored from the Great Plains and Corn Belt into the Southeast. A vigorous ridge complex, or heat ridge, will suppress diurnal convection mechanisms that are critical to water budgets in those regions, and the nature of the weak anticyclonic flow would tend to keep the seasonal easterlies confined to FL and the immediate Gulf Coast. I would also point out that a tendency for downslope flow off of the Ozark Plateau and Appalachian Mountains may further eliminate chances for precipitation in the "Arklatex" and Piedmont (S VA....NC....SC....NE GA) vicinities.
Conversely, the states to the west and north of the positive height anomaly will have the best chances at significant rainfall. If a remnant of the now-powerful Aleutian Islands/Gulf of Alaska storm complex remains through this summer (a likely possibility), then the draw of Gulf of Mexico and Sea of Cortez dewpoints will line up from the Front Range communities into the West Coast. The Pacific Northwest would have the greatest positive deviation from normal in regard to seasonal rainfall, and the Desert and Intermountain Regions could see a very prominent "monsoon" season, replete with severe thunderstorms and wash/valley flooding. Along the northern rim of the anticyclone, stretching from AB and MT into the Great Lakes and Northeast, cold frontal progression (dependent on strength/velocity of the polar westerlies) should produce normal or greater output of convection. Therefore, the states bordering Canada are probably looking at rain output close to or above average for the summer months.
Tropical Cyclone Outlook Through November 1
The three factors I most often look at when considering potential threats for hurricanes and other tropical disturbances are features related to synoptic climatology (including expected position of the 500MB longwave features), sea surface temperature trends, and developments with respect to ENSO. We know that a strong, warm deviation in the equatorial Pacific Ocean (El Nino) is associated with the expansion tropical cyclone development near the west shores of Central America and Mexico, while at the same time linked to lesser formation and organization of those systems over the Atlantic Basin. Conversely, a cooling of the thermal ribbon between the Galapagos Islands and Polynesia (La Nina) is usually viewed as lessening hurricane threats in the Pacific theater while favoring greater incidence (and stronger individual storms) of warm-core cyclogenesis from the western African coastline into the Gulf of Mexico and Caribbean Sea.
With the expectation of an extensive heat ridge over the central and eastern U.S., plus a diminishing weak El Nino (and probable formation of a faint La Nina anomaly), prospects for an active hurricane season in the Atlantic Ocean and its various branches appears likely. The Pacific theater hurricane season, which got underway May 15, may briefly flare up, and feature greater threats to Mexico than was the case the past two years. As was the case in 2004, Atlantic Basin tropical cyclone development may be delayed. While one can never rule out a freak subtropical or convective spin-up, the presence of very cold waters off the coast of the Southeast into the Sargasso Sea will serve as a pronounced deterrent for warm-core convection. Low-latitude westerlies, common during weak El Nino influence, are still ongoing over Central America and the Caribbean Sea (as can be seen by the long-lived excessive rainfall event over parts of the Greater Antilles earlier this week). It will likely take about two months for elimination of west-to-east winds and cold impulses and at least that much time for waters to warm. So any real hurricane threats to populations in North America or the adjacent islands is unlikely to occur before August 1.
Another consideration of possible high-impact tropical systems is what happens to ridging and ITCZ impulses over Africa. Normally, a moderately strong, wide-area Azores heat ridge is needed for "Cape Verde" type tropical waves to progress westward and remain intact enough to threaten the major islands or North America. If the subtropical high is not in just the right place or of a certain strength, the convective clusters emerging off the shoreline of Africa may shear apart, turn northward or merge with TUTT signatures before they reach western shores. Recent satellite views of the Sahara Desert show a strong, flat anticyclone stretching the entire length of above-equatorial Africa; the tropical disturbances, meanwhile, tend to be large but intermittent. Extrapolating on these trends, perhaps 25 to 35 percent of waves will attain a far enough westward heading to affect weather in the various island chains and the U.S. Since a fairly impressive heat ridge figures to be in place around 35-40 N Latitude ranging into the Southeast, a few surviving impulses may target S FL and continue on to communities in the western Gulf of Mexico. Later in the season, as the positive height anomaly over the midsection of the nation begins to collapse due to an increasing and retrogressive mean trough (shifting from New England and the Maritime provinces to 90 W Longitude), it is possible that a warm-core cyclone could recurve northeastward and affect locations along the Eastern Seaboard or over Appalachia.
Tropical Cyclone Forecast Through November 1
15 Named Storms (Subtropical, Tropical, or Hurricane)
2 Subtropical Storms
7 Hurricanes
3 Major Hurricanes
Summary
Teleconnections on key longwave features in late spring suggest that the dominant system over North America during the summer of 2005 will be a moderate to strong heat ridge (core heights near and sometimes exceeding 594dcm at 500MB) centered in the general vicinity of Kansas City MO. There may be periods where the positive height anomaly extends into the Upper Midwest or Appalachia. The position of the anticyclone, in combination with other important weather systems, favors the following development in apparent weather between now and September:
1) Extreme heat from the Great Plains into the Corn Belt and interior of Dixie
2) Best potential for heavy to severe thunderstorms across the Desert and Intermountain Regions, and the states bordering Canada into the Northeast
3) Drought conditions possible under the ridge, with the Gulf Coast seeing near normal amounts of diurnal convection
4) Cooler than normal temperatures over the Pacific Northwest
5) Hurricane season more active than normal, but getting a relatively late start; prime threat areas in the U.S. are S FL and TX/LA
Here is his graphic--if u ask me, I say this means the entire US coast is at rist but you be the judge....
