US Weather Commentary

Computer Models & Outlooks depicting this cooler weather for Central & Southern U.S., but any Eastern Blocking still on Hold....

- Look for NWS outlook maps and other forecasts to maintain these South vs. North contrasts.......

NORTHEAST:

The region is wrapping up its robust Mild Phase (in which several days in the past week flirted around 60°F), and is now gradually contending with some more seasonably cool days.  Courtesy of rotating short-waves, "weather schizophrenia" continues this December, characteristic of regimes that don't yet have Blocking yet also only have a moderate-El Niño.  The absence of snow-pack across the Northeast makes it difficult to squeeze out any chilly readings, but it also should be reminded that climatologically New York City doesn't pick up its first inch of snowfall until around New Year's.  Also be aware that any future Canadian cold waves diving down West of the Mississippi typically trigger a "See-Saw" reaction, with southerly advection pushing very mild air up across the East, right before any colder air filters to the Atlantic.

~ Our Winter Season Forecast (made in July): Above-Normal Heating Degree Days [December-March]; excess Snow & Ice Storms. Site-Specific case-studies: <http://www.weather2000.com/fcst_discussion.html>

SOUTHEAST:

The most dramatic turnaround following the National Mild Phase will be experienced across the Southeast, where Atlanta will go from a current streak of days breaking 70°F, to next week struggling to break 50°F.  The PNA pattern has resumed its positive phase, and correspondingly will yield much cooler, damper and stormier weather for the entire region to conclude the month of December.  However, portions of the deep Southeast (mostly Florida and nearby) continue to dry out at the surface, so we continue to warn that this poses an ongoing concern for hard freezes right to the Gulf coastline and deep into Florida this Winter.

~ Our Winter Season Forecast (made in July): Above-Normal Heating Degree Days [December-March]; excess clouds, precipitation; anomalous hard-freeze events (late 2006). Site-Specific case-studies: <http://www.weather2000.com/fcst_discussion.html>

NORTH-CENTRAL:

The Western Great Lakes are supposed to be the pivot point of Cold and Warm patterns this Winter, and nowhere is this illustrated better than in Chicago IL which experienced a shocking 4 days below 9°F this month, and then an equally surprising 4 days cracking 50°F.  The next tongue of Polar Air is crossing the U.S.-Canadian border this week, heralding another Winter Storm of Snow and Ice, spanning from Kansas up to South Dakota. {It should also be reminded that areas West of the Great Lakes will always be the quickest to resume their Mild Winter patterns this year after any cold waves, especially where snow is scarce or absent.} The classic North-Central signature of a modest El Niño, northerly displaced Jet Stream and minimal snowfall, will carry through the balance of December.

Our Winter Season Forecast (made in July): Above-Normal Heating Degree Days and Lake-Effect events [Great Lakes and Eastward]; Below-Normal Heating Degree Days; reduced precipitation [West of Great Lakes]. Site-Specific case-studies: <http://www.weather2000.com/fcst_discussion.html>

SOUTH-CENTRAL:

Sunny skies, ridging to the North and dry ground have assisted the region to warm nicely, such as Dallas and Houston consistently reaching the 70's to around 80°F over the past week.  Temperatures for the Southern States are always vulnerable to reductions wrought by cloudiness, moisture and storms, so the positive phase of the PNA pattern will bring about appreciably cooler/wetter weather, commencing today and sinking Dallas into highs in the 40's by next week.  This weather theme should then be the norm to finish out December particularly for areas toward the Western Gulf, but like their Northern counterparts, the Southern Plains and Southern Rockies will be the quickest to resume warmer patterns.

Our Winter Season Forecast (made in July): Seasonable Heating Degree Days; excess clouds, precipitation; anomalous hard-freeze events (late 2006). Site-Specific case-studies: <http://www.weather2000.com/fcst_discussion.html>

NORTHWEST:

The Pacific Northwest will contend with typical 'Wet Season' storminess near the Coast and Cascades, but the precipitation amounts will taper down noticeably right after Christmas.  Some powerful coastal gales can also be expected this week until the pressure gradient pattern breaks down thanks to positive-PNA inspired High Pressure.  Correspondingly, a significantly milder Northwest/Northern Rockies is in store for the final week of December.

Our Winter Season Forecast (made in July): Below-Normal Heating Degree Days; Below-Normal Precipitation (December-March); Localized cold snaps (particularly pre-December). Site-Specific case-studies: <http://www.weather2000.com/fcst_discussion.html>

SOUTHWEST:

Northern/Central California and Nevada have now been contending with strong coastal storms and mountain snows of their own, but this also will take a breather right after Christmas.  A classic foot-print of even weak El Niño events, cloud-cover and precipitation is also being carried into the desert Southwest and southern Rockies.  Interior/Desert hubs most reliant on sunshine and most vulnerable to moisture impacts on temperatures, will correspondingly sustain negative departures during the short-term.  But a warm-up is in store starting with California this weekend and expanding to the Southwest by next week.

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