FXUS06 KWBC 011902 PMDMRD Prognostic Discussion for 6 to 10 and 8 to 14 day outlooks NWS Climate Prediction Center College Park, MD 300 PM EDT Tue April 01 2025 6-10 DAY OUTLOOK FOR APR 07 - 11 2025 The 0z GEFS, ECENS, and CMCE are in very good agreement regarding an amplified 500-hPa height pattern across North America. Troughing is forecast over the eastern contiguous U.S. (CONUS), with ridging becoming established across the western CONUS. Troughing initially forecast across central Alaska is predicted to weaken, with ridging and positive height anomalies expanding over the state by the end of the period. Today’s manual 6-10 day 500-hPa height blend depicts above-normal heights across much of the western CONUS, and below-normal heights over the northeastern quadrant of the CONUS. The largest positive and negative anomalies are indicated closer to the U.S./Canadian Border. Near-normal heights are favored across the south-central and southeastern CONUS. Near- to slightly below-normal heights are depicted over much of Mainland Alaska and the Alaska Peninsula, with above-normal heights forecast over the western Aleutians, far eastern Mainland, and Southeast Alaska. Probabilities for below-normal temperatures are increased over much of the central and eastern CONUS underneath increasing northerly mid-level flow behind a frontal boundary predicted to move through at the outset of the period, with the highest chances (greater than 80 percent) across the Lower Mississippi Valley. There is some concern for early spring frosts or freezes across some areas as relatively colder temperatures coincide with emerging vegetation. Ridging forecast across the West favors elevated probabilities of above-normal temperatures. Troughing predicted over central Mainland Alaska supports increased chances for above-normal temperatures over the southern and eastern parts of the state due to enhanced southerly flow. Conversely, below-normal temperature chances are increased on the backside of the mean trough axis across western Mainland. Increasing mid-level heights over the Aleutians supports enhanced near- to above-normal temperatures chances. Above-normal temperatures continue to be favored across Hawaii. A frontal system is favored to quickly progress east at the outset of the period. While above-normal precipitation probabilities are increased across portions of the southeastern U.S., a broad area of enhanced below-normal precipitation probabilities are forecast across much of the western CONUS and building into the Great Plains and Midwest as surface high pressure becomes established. Elevated probabilities for above-normal precipitation are favored across eastern Alaska due to enhanced onshore flow ahead of troughing. Near- to below-normal precipitation chances are increased across the far western Mainland and the Aleutians underneath a more northerly mid-level flow pattern. Above-normal precipitation is forecast across Hawaii supported by the consolidation forecast tool. The official 6-10 day 500-hPa height blend consists of 34% of Today's 0z GFS Ensemble Mean centered on Day 8, 33% of Today's 0z European Ensemble Mean centered on Day 8, and 33% of Today's 0z Canadian Ensemble Mean centered on Day 8 FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: Above average, 4 out of 5. Good agreement with regard to overall synoptic picture, offset by stronger ridging depicted in ECMWF and subsequent solutions offered by ECMWF-based tools. 8-14 DAY OUTLOOK FOR APR 09 - 15 2025 The 500-hPa height pattern predicted during week-2 is similar to that of the 6-10 day period, with minimal eastward progression and decreasing amplification of features. The dynamical models remain in good agreement regarding ridging (troughing) across the western (eastern) CONUS. The week-2 manual 500-hPa height blend depicts below-normal heights for most areas east of the Mississippi River, and above-normal heights upstream to the west. Weakly above-normal heights are depicted across Alaska underneath a weak trough signature persisting across the central Mainland. Larger positive height anomalies are forecast across the Aleutians and far western Mainland associated with ridging centered across eastern Russia and the Bering Sea. Below-normal temperature probabilities remain elevated across the eastern half of the CONUS as well as the Southern Plains, with the greatest probabilities (>60%) over portions of the southeastern U.S. Enhanced probabilities are indicated for above-normal temperatures across the West, especially the Great Basic (>70%), under the largest forecast positive 500-hPa height departures. As the mean trough axis shifts to the east and weakens, warming temperatures are forecast across the Northern and Central Plains resulting in an eastward expansion of the enhanced above-normal temperature chances to include these areas. Chances for above-normal temperatures remain across southern Alaska due to continued southerly flow. A slight tilt toward below-normal temperatures is favored over the western Mainland, supported by a teleconnection with the upstream positive height anomaly center and enhanced northerly mid-level flow. Increased probabilities for above-normal temperatures remain forecast across Hawaii. Ridging over the West, combined with surface high pressure over the East, favor increased chances for below-normal precipitation over much of the CONUS, with chances above 50 percent for portions of the Great Basin and Lower MIssissippi Valley. Lingering frontal activity across the southern Florida Peninsula tilts the odds toward above-normal precipitation supported by the ECENS and GEFS reforecast tools, with near-normal precipitation favored along the immediate East Coast from the Outer Banks northward tied to possible surface low development later in the period. A slight tilt toward elevated odds for above (below) normal precipitation remains favored across eastern (western) Mainland Alaska underneath slightly enhanced southerly (northerly) mid-level flow associated with weak troughing across the Central Mainland, although a much drier signal is noted in the dynamical models across coastal southeastern Alaska later in the period compared to earlier in the period. Above-normal precipitation chances are increased across Hawaii. The official 8-14 day 500-hPa height blend consists of: 33% of Today's 0z GFS Ensemble Mean centered on Day 11, 34% of Today's 0z European Ensemble Mean centered on Day 11, and 33% of Today's 0z Canadian Ensemble Mean centered on Day 11 FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: Above average, 4 out of 5. Good agreement with regard to overall synoptic picture, offset by stronger ridging depicted in ECMWF and subsequent solutions offered by ECMWF-based tools. FORECASTER: Daniel Barandiaran Notes: Automated forecasts are issued on Saturday and Sunday. Occasionally manual intervention is necessary to address quality control and consistency issues. In these cases, forecasts are manually drawn but a full discussion is not issued. The notation for the categorical forecast indicated on the maps is the same as that in the tables: A-above N-near normal B-below The temperature map shows regions with > 33% chance of being warmer (orange, "A"), colder (blue, "B"), or close to (unshaded, "N"). Historical average values for the calendar period of the forecast (dashes, "f"). Labels on the shaded lines give the probability (> 33%) of the more likely category (B or A). Probability of N is always < 40%. The precipitation map shows regions with > 33% chance of being wetter (green, "A"), drier (tan, "B"), or close to (unshaded, "n"). Historical median values for the calendar period of the forecast (dashes, "inches"). Labels on the shaded lines give the probability (> 33%) of the more likely category (B or A). Probability of N is always < 40%. In the southwest and other climatologically dry regions - there will be a greater than 33.3% chance of no precipitation and occasionally even a normal (i.e. Median) value of zero - especially during the dry seasons. In such cases a forecast of near normal is effectively a forecast of little or no precipitation. The climate prediction center uses 1991-2020 base period means as reference in the climate outlooks. The next set of long-lead monthly and seasonal outlooks will be released on April 17. Analogs to the 5 day mean observed pattern centered 3 days ago (D-3) for the region from 20N to 70N latitude and 175E to 60W longitude include the 5 day periods centered on the following dates: 19970313 - 19670318 - 19630404 - 19900409 - 19630329 Analogs to the 7 day mean observed pattern centered 4 days ago (D-4) for the region from 20N to 70N latitude and 175E to 60W longitude include the 7 day periods centered on the following dates: 19970313 - 19670318 - 19630403 - 19630328 - 19890312 6-10 DAY OUTLOOK TABLE Outlook for Apr 07 - 11 2025 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A A OREGON A B NRN CALIF A B SRN CALIF A B IDAHO A B NEVADA A B W MONTANA A B E MONTANA A B WYOMING A B UTAH A B ARIZONA A B COLORADO A B NEW MEXICO A B N DAKOTA A B S DAKOTA A B NEBRASKA A B KANSAS N B OKLAHOMA B B N TEXAS B B S TEXAS B B W TEXAS B B MINNESOTA N B IOWA N B MISSOURI B B ARKANSAS B B LOUISIANA B B WISCONSIN B B ILLINOIS B B MISSISSIPPI B B MICHIGAN B B INDIANA B B OHIO B B KENTUCKY B B TENNESSEE B B ALABAMA B N NEW YORK B N VERMONT B N NEW HAMP B N MAINE B N MASS B N CONN B N RHODE IS B N PENN B N NEW JERSEY B N W VIRGINIA B N MARYLAND B N DELAWARE B A VIRGINIA B N N CAROLINA B A S CAROLINA B A GEORGIA B A FL PNHDL B A FL PENIN B A AK N SLOPE B A AK ALEUTIAN B B AK WESTERN B N AK INT BSN A A AK S INT A A AK SO COAST A A AK PNHDL A A 8-14 DAY OUTLOOK TABLE Outlook for Apr 09 - 15 2025 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A N OREGON A B NRN CALIF A B SRN CALIF A B IDAHO A B NEVADA A B W MONTANA A N E MONTANA A B WYOMING A B UTAH A B ARIZONA A B COLORADO A B NEW MEXICO A B N DAKOTA A N S DAKOTA A B NEBRASKA A B KANSAS A B OKLAHOMA A B N TEXAS N B S TEXAS B B W TEXAS A B MINNESOTA A N IOWA A B MISSOURI N B ARKANSAS B B LOUISIANA B B WISCONSIN A N ILLINOIS N B MISSISSIPPI B B MICHIGAN B N INDIANA B B OHIO B B KENTUCKY B B TENNESSEE B B ALABAMA B B NEW YORK B N VERMONT B N NEW HAMP B N MAINE B A MASS B N CONN B N RHODE IS B N PENN B N NEW JERSEY B N W VIRGINIA B B MARYLAND B N DELAWARE B N VIRGINIA B N N CAROLINA B B S CAROLINA B B GEORGIA B B FL PNHDL B B FL PENIN B N AK N SLOPE N N AK ALEUTIAN N N AK WESTERN B N AK INT BSN A A AK S INT A A AK SO COAST A A AK PNHDL A A LEGEND TEMPS WITH RESPECT TO NORMAL PCPN WITH RESPECT TO MEDIAN A - ABOVE N - NEAR NORMAL A - ABOVE N - NEAR MEDIAN B - BELOW B - BELOW THE FORECAST CLASSES REPRESENT AVERAGES FOR EACH STATE. NORMAL VALUES - WHICH MAY VARY WIDELY ACROSS SOME STATES - ARE AVAILABLE FROM YOUR LOCAL WEATHER SERVICE FORECAST OFFICE. FOR ADDITIONAL INFORMATION SEE MESSAGE FXUS06 KWBC - ON AWIPS AS PMDMRD. $$