US Day 3-7 Hazards Outlook
NWS Weather Prediction Center College Park MD
304 PM EDT Thu Aug 29 2019
 
Valid Sunday September 01 2019 - Thursday September 05 2019
 
Hazards:
- Heavy rain across portions of the Great Lakes, the Upper Mississippi Valley, and the Northern 
Plains, Mon, Sep 2.
- Heavy rain across portions of the Great Lakes and the Upper Mississippi Valley, Thu, Sep 5.
- Heavy rain across portions of the Southeast and the Mid-Atlantic, Sun-Thu, Sep 1-Sep 5.
- Heavy rain across portions of the Mid-Atlantic, the Northeast, and the Great Lakes, Sun, Sep 1.
- Flooding possible across portions of the Central Plains and the Middle Mississippi Valley.
- Flooding occurring or imminent across portions of the Central Plains, the Middle Mississippi 
Valley, the Southern Plains, and the Northern Plains.
- Excessive heat across portions of California and the Southwest, Sun, Sep 1.
- High winds across portions of the Southeast, Sun-Thu, Sep 1-Sep 5.
- High significant wave heights for coastal portions of the Southeast, Sun-Tue, Sep 1-Sep 3.
- Heavy rain across portions of mainland Alaska, Sun-Mon, Sep 1-Sep 2.
- Heavy rain across portions of mainland Alaska, Sun, Sep 1.
- High winds across portions of mainland Alaska and the Aleutians, Sun, Sep 1.
 
Detailed Summary:

Over the continental U.S., Hurricane Dorian will be the most significant hazard during this 3-7 day 
period. The latest advisory from the National Hurricane Center has Dorian entering the central 
Florida peninsula on Monday morning as a major hurricane. Dorian is then expected to turn more 
northwestward and eventually northward, bisecting the peninsula on Tuesday-Wednesday before lifting 
into southeastern Georgia by Thursday. Expect heavy rainfall and high winds across much of the 
peninsula from Monday through Wednesday, with the highest winds generally along and to the right of 
the storm track. In addition, there will be threat for significant waves/storm surge along the 
Florida east coast and possibly northward along the Georgia coast from Monday-Wednesday. Rainfall 
totals associated with Dorian of 5-10 inches are expected, with locally higher amounts. There's 
still some uncertainty with the exact track and speed, so adjustments to the currently depicted 
hazard areas are likely during tomorrow's forecast. Please refer to the National Hurricane Center 
(www.nhc.noaa.gov) for the latest information on Dorian.

Across the northeastern states, a progressive short wave trough, along with a band of concentrated 
deep moisture, will support organized showers Sunday into Monday. At the moment, the best threat 
for heavy amounts (around 1-2 inches) is across central/northern New York into western sections of 
Vermont on Sunday as a result of increased lift associated with upper diffluent flow.

Farther west, strengthening low pressure in response to a short wave trough moving through 
south-central Canada will track along the Canadian/U.S border from the northern Plains into the 
western Great Lakes states Monday-Tuesday. While moving relatively quickly, strong instability 
ahead of its associated cold front and increasing moisture convergence along a quasi-stationary 
boundary north of the surface low will likely spin up a period of heavy organized 
showers/thundershowers. Current guidance generally agrees with this scenario, but with some 
differences in the north-south placement of the heaviest rain. At the moment, believe the best 
chance is across northern Minnesota, where locally 1-2 inches are possible. Later in the period 
(late Wednesday-Thursday), another system may move across the northern Plains and western Great 
Lakes states and bring the threat for locally heavy rainfall. Model consensus is for this to be 
farther south than the event earlier in the week, but confidence at this time range on the 
specifics is low.

In the Southwest, it looks like one more day of excessive heat will start the month of September. 
The area affected will mostly be from the Las Vegas region southward through far western Arizona 
and lower desert region of southeastern California. Slightly cooler weather is expected next week 
as the upper ridging over the area weakens.

In Alaska, a strong occluded cyclone will lift from the Aleutian chain into the eastern Bering Sea 
and into the Yukon Delta during this Labor Day weekend. High winds are likely (mostly Sunday) over 
the central and eastern Aleutians and across Bristol and Kuskokwin Bays. In addition this storm 
will bring upwards of 1-1.5 inches of rainfall to the southern Kuskokwim mountain region on Sunday, 
and locally up to 2-3 inches Sunday-Monday in favored orographic regions along the Aleutian and 
Alaska Ranges, the Kenai peninsula and around Anchorage.

Klein