Today Through the Fourth Friday (22 to 28 days) Weather Outlook for the U.S. and a Six-Day Forecast for the World: posted September 5, 2024
This article focuses on what we are paying attention to in the next 48 to 72 hours. The article also includes weather maps for longer-term U.S. outlooks and a six-day World weather outlook which can be very useful for travelers.
First the NWS Short Range Forecast. The afternoon NWS text update can be found here after about 4 p.m. New York time but it is unlikely to have changed very much from the morning update. The images in this article automatically update.
Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Thu Sep 05 2024
Valid 12Z Thu Sep 05 2024 – 12Z Sat Sep 07 2024…Very heavy rain and the threat for scattered to numerous instances of
flash flooding continues for the Gulf Coast states the next couple of
days……Dangerous heat wave intensifies over the Southwest and West Coast…
Heavy rain and flash flooding remain in the forecast along the Gulf Coast
as a stationary front and coastal low drive multiple days of widespread
showers and thunderstorms across the region. The elongated area of low
pressure and front from the north-central to western Gulf will keep the
greatest focus for repeated rounds of storms moving onshore over the
central Gulf Coast and upper Texas Gulf Coast today (Thursday),
potentially spreading a bit further northward into the Lower Mississippi
Valley. Very moist Gulf air continues to contribute to very efficient
downpours with these storms, approaching 2-3″ per hour in some cases,
exacerbating the threat for heavy totals and flash flooding. There is now
a Moderate Risk (level 3/4) of Excessive Rainfall for southeastern
Louisiana where prior days rainfall has lead to very wet antecedent
conditions and brings a locally greater threat for scattered to numerous
instances of flash flooding, especially for the urban areas around greater
New Orleans. A broader Slight Risk (level 2/4) is in place across the
region for additional scattered instances of flash flooding. An
approaching upper-level wave will help to shift the focus for heavy
rainfall a bit eastward on Friday as the front begins to meander away from
the western Gulf and lift northward into southern Georgia, leading to
decreasing rain chances further West. Another Slight Risk of Excessive
Rainfall extends from the central Gulf Coast eastward through the Florida
Panhandle into southern Georgia where a similar threat for intense heavy
downpours with repeated rounds of storms will lead to several inches of
rain, and the potential for scattered instances of flash flooding.
Temperatures will remain well below average across the region north of the
frontal boundary and in the presence of widespread rain and cloud cover
with mostly upper 70s and low 80s. Some locations may only reach into the
low 70s Friday. On the other hand, it will be hot south of the front
across the Florida Peninsula, with highs in the low 90s. A Heat Advisory
is in place for South Florida where the combination of heat and humidity
will lead to heat indices in the 105-110 degree range.A dangerous heat wave will intensify over the Southwest and West Coast the
next couple of days with a strong upper-level ridge now settled over the
region. Forecast high temperatures Thursday and Friday range from the 110s
for the Desert Southwest, low 100s to near 110 for southern California,
mid-100s for the central California Valleys, and the 90s to low 100s for
central/northern California and into the Pacific Northwest. Several
record-tying/breaking highs are possible across the Pacific Northwest.
Widespread heat-related warnings and advisories are in place given the
heightened threat for heat-related illness to anyone without efficient air
conditioning or adequate hydration. While not quite as hot, highs will be
well above average and potentially uncomfortable even for some immediate
coastal locations with temperatures reaching into the 80s.Elsewhere, a broad area of showers and thunderstorms is expected ahead of
a pair of cold fronts passing through the Upper Midwest/Great Lakes,
Central Plains, and central/southern High Plains and adjacent Rockies. The
greatest chance for some moderate to locally heavy rainfall will be under
the influence of an upper-level trough over the Upper Midwest/Great Lakes,
and where upslope flow enhances storms over the southern Rockies. A few
isolated instances of flash flooding will be possible in the southern
Rockies given recent rains and some more sensitive burn scars. Storm
chances with moderate to locally heavy rainfall will continue ahead of the
front as it pushes eastward through the Great Lakes overnight Thursday and
into the Lower Great Lakes/Upper Ohio Valley on Friday. Some storms may
begin to spread into the Northeast and Mid-Atlantic by early Saturday
morning. Temperature-wise, the passing cold front will bring well below
average, Fall-like temperatures to the Northern Plains and Upper Midwest
Thursday, with highs in the 60s to low 70s. Temperatures will be rather
chilly for the Upper Great Lakes by Friday as highs drop into the 50s.
Conditions will be much warmer ahead of the front Thursday over the
Midwest and Ohio Valley with highs in the mid-80s to low 90s. The
approaching front will bring temperatures down into the 70s for portions
of the Midwest Friday. Mild conditions will continue for much of the East
Coast through Friday with highs in the upper 70s to low 80s.