SYNOPSIS: At the start of the period the jet stream pattern over the Lower 48 States will be flowing west to east as a deep upper level trough continues lifting out from the eastern states and a new trough is beginning to develop over the western states. Unseasonably cold temperatures are expected for much of the northernmost tier of states for the first day of the assessment period. The models indicate that the jet stream flow will then amplify, with a trough developing over the western states and moving into the middle of the nation. This will support more stormy weather for the eastern half of the nation during the middle of the assessment period, but bring some relief to drought areas of the West. Some severe weather is indicated ahead of the trough as a sharp short wave swings through the base of the trough and across the Southern Plains and Midwest. During the later half of the period the flow is expected to be progressive with moderate amplitude waves moving fairly quickly from west to east. This should bring rather typical, changeable Fall weather to much of the nation. Throughout the period seasonably stormy weather is indicated for Alaska, with periods of gale force winds along the Aleutian chain and west and south coasts.

HAZARDS

DETAILED SUMMARY

For Monday October 18 - Wednesday October 20, 2004: North of a frontal zone much below normal temperatures are expected for much of the northernmost tier of states on Oct 18. A long wave trough is forecast to amplify over the western states and short wave impulses moving through this trough are expected to modulate the periods of storminess in the generally unsettled weather ahead of the through. One strong impulse is forecast to bring a chance of severe weather from northeastern Texas to the southern half of Missouri by Oct. 20, although there is still some uncertainty at this time range. Elsewhere, flooding is expected to continue over portions of Florida and southern Georgia as the flat land in those areas continues to slowly drain the water from earlier tropical systems. A stormy period is anticipated for Alaska, with periods of gale force winds winds expected for the Aleutians and much of Alaska's coast on Oct 18 and 19. Some precipitation is likely in drought areas, with some early season snow possible for northern parts of the Plains as well as the northern Rockies.

For Tuesday October 26 - Friday October 29, 2004: The western area of long term drought is likely to continue through this period. Although the timing is uncertain, the latest extended model runs indicate additional strong storms for Alaska during this period. No other potential hazards can be reliably identified at this time.

Please consult local NWS Forecast Offices for short range forecasts and region-specific information.