WPC Medium Range Archive
Medium Range Products Valid On:
(Day 7 PMDEPD: Valid 06/30/2022 to 07/04/2022)
Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
359 PM EDT Mon Jun 27 2022
Valid 12Z Thu Jun 30 2022 - 12Z Mon Jul 04 2022
...Weather Pattern Overview...
A relatively zonal upper level flow pattern in place over the
northern tier of the nation this week may amplify over the holiday
weekend as a closed low/trough develops near the Pacific NW/West
Coast and as a hot ridge lingering over the U.S. southern tier
builds over the north-central states. This scenario may also
support holiday amplification of a broad trough over the Northeast
U.S. underneath a deep Hudson Bay closed vortex. NHC is monitoring
a tropical wave/disturbance over the northern Gulf of Mexico,
riding underneath the ridge.
...Guidance Evaluation/Predictability Assessment...
The 00/06/12 UTC model and ensemble guidance suite remain in very
good synoptic scale agreement through medium range time scales.
The WPC medium range product suite was primarily derived from a
model and supporting ensemble mean composite blend days 3-7
(Thursday-July 4th). This maintains good overall WPC product
continuity, and individual system forecast differences seem well
mitigated by the blend process. Potential tropical influences into
Texas later this week and the subsequent deep moisture feed/QPF
threat inland into several frontal systems downstream remain less
...Sensible Weather and Potential Hazards...
A lingering stationary front along the Gulf Coast and southeast
coastal U.S. will likely promote the development of scattered to
numerous showers and storms for the end of the work week. There
may be an enhanced area of heavier rainfall across portions of
Texas based on recent Canadian/ECMWF runs, and this will likely be
dependent on any organized low pressure areas that develop over
the western Gulf of Mexico as per NHC. Farther north, a corridor
of showers and storms is likely along and ahead of a cold front
that will be slowly tracking towards the southeast across the
Midwest, Ohio Valley, and Great Lakes regions going into the
weekend. The trailing front could pool deep Gulf/tropical moisture
from the Plains to the Mid-Atlantic over the holiday weekend as
shortwaves round the northern periphery of the upper ridge.
Monsoonal moisture over the Four Corners region may also result in
scattered areas of heavier rainfall with impulses and moisture
lifting on the western periphery of the upper ridge.
In terms of temperatures, expect readings to be running up to 10
degrees above normal ahead of the front from the Upper Midwest to
the Northeast U.S. to close out the week, followed by seasonal
temperatures going into the Saturday to Monday time period. Heat
is likely to build again across the central and northern Plains by
next Monday in response to the building upper ridge, and slightly
cooler conditions for the West Coast region that may include some
July rainfall over the Northwest with height falls/system approach.
Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
- Heavy rain across portions of southern and eastern Texas,
Thu-Sat, Jun 30-Jul 2.
- Heavy rain across portions of the central Plains and Middle
Mississippi Valley, Fri-Sat, Jul 1-Jul 2.
- Heavy rain across portions of the Southern Rockies and the
Southwest, Thu-Mon, Jun 30-Jul 4.
- Flooding occurring or imminent across portions of the Upper
Mississippi Valley and the Northern Plains.
- Flooding likely across portions of the Middle Mississippi Valley
and the Northern Great Basin.
- Excessive heat across portions of the north-central Plains, Mon,
WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation, experimental excessive rainfall
outlook, winter weather outlook probabilities and heat indices are