Valid Tuesday June 08, 2021 to Monday June 14, 2021
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT May 31 2021
Synopsis: Model guidance shows mid-level high pressure established across the East at the beginning of the forecast period, bringing with it the potential for record high temperatures for the Northeast. This high pressure is forecast to lessen over the course of the week, keeping temperatures warm, but less concerning from a health perspective. Periods of enhanced onshore flow out of the western Gulf of Mexico have occurred across portions of the Southern Plains and Lower Mississippi Valley over the last month, with another event possible at the start of Week-2. Locally heavy rainfall and river flooding may result across portions of the Southern Plains and Mississippi Valley. Mid-level low pressure is forecast over the Bering Sea and near the Pacific Coast throughout Week-2, but given the ongoing dry season for both locations no associated precipitation hazards are anticipated.
Hazards
Moderate risk of excessive heat for portions of the Northeast, Tue-Wed, Jun 8-9.
Slight risk of excessive heat for portions of the Northern and Central Plains, Upper and Middle Mississippi Valley, Great Lakes, Ohio Valley, Central Appalachians, Mid-Atlantic, and Northeast, Tue-Sat, Jun 8-12.
Slight risk of heavy rain for portions of the Southern Plains and Lower Mississippi Valley, Tue Jun 8.
Flooding possible for portions of East Texas and Louisiana.
Detailed Summary
For Thursday June 03 - Monday June 07: WPC Days 3-7 U.S. Hazards
For Tuesday June 08 - Monday June 14: At the beginning of Week-2 consensus exists among the ensemble means of the GEFS, ECMWF, and Canadian models regarding anomalous ridging located near Montreal. This setup is likely to help drive the 582 dm isohypse into Canada, a sign of potentially record-breaking heat during early to mid-June for the Northeast. The National Blend of Models reflects this, despite the substantial forecast lead time, with forecast highs (and associated daily records) on June 8th of 90F for Burlington, VT (91F), 91F for Bangor, ME (92F), and 88F for Caribou, ME (87F). Calibrated reforecast guidance shows a 10-20% chance of record highs from roughly Boston northward, supporting a moderate risk of excessive heat on June 8th and 9th. Reforecast guidance also indicates a slight risk of excessive heat stretching from the Dakotas eastward to the Atlantic, with the southern extent as far south as the U.S. capital region, for June 8th-12th.