Seasonal Cimate Forecast March 20, 2014
Written by Sig Silber
It looks like a fairly benign seasonal forecast. What does it mean for your area? And are there any hints about next winter?
Let’s talk first about April.
First let us look at the temperature forecast:
And now the precipitation:
And now let’s take a look at the next three months.
First Temperature:
And now the precipitation:
NOAA Explanation
Below is the key part of the NOAA explanation recognizing that it is focused on April, May and June. The graphic forecast (above) is for May June and July.
“CURRENT ATMOSPHERIC AND OCEANIC CONDITIONS REMAIN ENSO-NEUTRAL AND THE LATEST ENSO OUTLOOK FAVORS ENSO-NEUTRAL CONDITIONS TO CONTINUE THROUGH THE NORTHERN HEMISPHERE SPRING OF 2014. HOWEVER, AN EL NINO WATCH HAS BEEN ISSUED WHICH INDICATES CONDITIONS ARE FAVORABLE FOR EL NINO DEVELOPMENT WITHIN THE NEXT SIX MONTHS.
THE TEMPERATURE OUTLOOK FOR APRIL-MAY-JUNE (AMJ) 2014 INDICATES ELEVATED ODDS OF ABOVE NORMAL TEMPERATURES FOR ALASKA AND A REGION FROM THE WESTERN PACIFIC NORTHWEST TO CALIFORNIA AND NEVADA, EASTWARD ALONG THE SOUTHERN TIER OF THE CONTINENTAL U.S. THERE ARE ELEVATED CHANCES OF BELOW NORMAL TEMPERATURES FROM MONTANA TO THE GREAT LAKES.
THE AMJ 2014 PRECIPITATION OUTLOOK CALLS FOR ENHANCED PROBABILITIES OF BELOW-MEDIAN PRECIPITATION FOR SOUTHEAST ALASKA AND ALONG THE ENTIRE WEST COAST, WITH THE HIGHEST PROBABILITIES FOR AREAS OF NORTHERN CALIFORNIA AND THE ALASKA PANHANDLE.
IN AREAS WHERE THE LIKELIHOODS OF SEASONAL MEAN TEMPERATURES AND SEASONAL AMOUNTS ARE SIMILAR TO ACCUMULATED PRECIPITATION CLIMATOLOGICAL PROBABILITIES, EQUAL CHANCES (EC) IS SHOWN.”
I took a look out further given that:
“AN EL NINO WATCH HAS BEEN ISSUED WHICH INDICATES CONDITIONS ARE FAVORABLE FOR EL NINO DEVELOPMENT WITHIN THE NEXT SIX MONTHS.”
NOAA is not saying much about precipitation deviating from climatology but they are predicting a warm winter for the Northeast and Upper Midwest and actually most of the Norther Tier other than the Northwest.
Here is the longer term (a year actually) forecast explanation:
“PROGNOSTIC DISCUSSION OF OUTLOOKS – AMJ 2014 TO AMJ 2015
TEMPERATURE
THE AMJ 2014 TEMPERATURE OUTLOOK INDICATES ELEVATED PROBABILITIES OF ABOVE-NORMAL SEASONAL MEAN TEMPERATURES FOR ALL OF ALASKA, WESTERN AREAS OF THE PACIFIC NORTHWEST, CALIFORNIA AND NEVADA AND EASTWARD ALONG THE SOUTHERN TIER OF THE CONUS. THE PROBABILITIES OF BELOW-NORMAL TEMPERATURES ARE ELEVATED FOR AREAS STRETCHING FROM CENTRAL MONTANA ACROSS THE NORTHERN PLAINS TO THE GREAT LAKES.
STATISTICAL TOOLS, DYNAMICAL MODEL GUIDANCE FROM THE CFS, NMME AND IMME, OCN AND THE CON ALL POINTED TO ABOVE-NORMAL TEMPERATURES FOR MANY AREAS IN THE HIGHLIGHTED REGION. IN ADDITION, DRY SOIL MOISTURE CONSIDERATIONS PLAYED A ROLE AS WELL, ESPECIALLY FOR CALIFORNIA AND PARTS OF THE SOUTHWEST.
STATISTICAL FORECAST TOOLS KEYING ON ANOMALOUSLY WARM NORTH PACIFIC SSTS AND WET SOIL MOISTURE CONDITIONS ACROSS THE NORTHERN ROCKIES FAVORED BELOW-NORMAL TEMPERATURES FOR PARTS OF THE NORTHERN ROCKIES AND NORTHERN PLAINS AND THIS IS INDICATED BY THE CON TOOL. FURTHER EAST, SOME DYNAMICAL MODELS FAVOR CONTINUED TROUGHING ACROSS EASTERN NORTH AMERICA ESPECIALLY IN APRIL AND THIS ALONG WITH POTENTIAL IMPACTS FROM ANOMALOUSLY HIGH GREAT LAKES ICE COVER FAVOR EXTENSION OF THIS FORECAST AREA TO INCLUDE THE GREAT LAKES AREA. ANOMALOUSLY DEEP FROZEN SOIL IN MANY AREAS OF THE MIDWEST ALSO SUPPORT THIS FORECAST.
OUTLOOKS FROM MJJ THROUGH JAS 2014 WERE LARGELY UNCHANGED FROM THE PREVIOUS OUTLOOK AND INDICATE ELEVATED PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES FOR THE WESTERN AND SOUTHERN CONUS, ALONG THE EASTERN SEABOARD AND FOR ALASKA, SUPPORTED BY THE CON AND DYNAMICAL MODEL GUIDANCE.
INCREASING CHANCES FOR EL NINO AS SUMMER APPROACHES 2014 HAVE RESULTED IN SOME ADJUSTMENTS AT LONGER LEADS, PRIMARILY BASED ON EL NINO COMPOSITES DURING VARIOUS SEASONS. ELEVATED CHANCES FOR ABOVE-NORMAL TEMPERATURES FOR AREAS ACROSS THE SOUTHERN TIER OF THE CONUS WERE REDUCED AND THEN ELIMINATED IN THE SOUTHWEST DURING ASO AND SON RESPECTIVELY.
ABOVE-NORMAL TEMPERATURES FAVORED DURING THE LATE AUTUMN AND WINTER SEASONS WERE REMOVED ACROSS THE SOUTH AND REPLACED WITH EQUAL CHANCES, AS EL NINO TYPICALLY FAVORS BELOW-NORMAL TEMPERATURES IN THESE AREAS. IF PROSPECTS FOR EL NINO CONTINUE TO INCREASE, PROBABILITIES FOR BELOW-NORMAL TEMPERATURES ACROSS THE SOUTH MAY BE ELEVATED IN SUBSEQUENT OUTLOOKS. ALSO, DURING THE LATE AUTUMN AND WINTER SEASONS THROUGH JFM 2015, THE AREA OF ELEVATED ABOVE-NORMAL TEMPERATURES WAS EXTENDED WESTWARD TO THE NORTHERN ROCKIES.
IN AREAS WITHOUT SUBSTANTIAL AND RELIABLE CLIMATE SIGNALS, EQUAL CHANCES OF BELOW, NEAR AND ABOVE-NORMAL SEASONAL MEAN TEMPERATURES ARE INDICATED.
PRECIPITATION
CLIMATE SIGNALS FOR PRECIPITATION ARE QUITE WEAK AND WHAT SIGNALS ARE INDICATED FROM VARIOUS FORECAST TOOLS OFTEN CONFLICT, EVEN AT THE EARLIEST LEAD. MOREOVER, POTENTIAL TRANSITIONING TOWARDS EL NINO FURTHER ADDS UNCERTAINTY IN THE PRECIPITATION OUTLOOKS AS WE MOVE FORWARD INTO THE SUMMER MONTHS.
THE AMJ 2014 PRECIPITATION OUTLOOK INDICATES ENHANCED PROBABILITIES OF BELOW-MEDIAN SEASONAL ACCUMULATED PRECIPITATION FOR THE WEST COAST NORTHWARD TO INCLUDE THE ALASKA PANHANDLE AND PARTS OF SOUTHEAST ALASKA. MUCH OF THE OUTLOOK IS DESIGNATED AS EQUAL CHANCES, OR CLIMATOLOGICAL PROBABILITIES OF BELOW, NEAR AND ABOVE-MEDIAN SEASONAL ACCUMULATED PRECIPITATION. THE PRIMARY DRIVER FOR THE AMJ OUTLOOK WAS DYNAMICAL MODEL GUIDANCE FROM THE CFS, NMME AND IMME, WITH THE GREATEST PROBABILITIES ACROSS NORTHERN CALIFORNIA AND THE ALASKA PANHANDLE WHERE AGREEMENT WAS GENERALLY THE BEST. SIMILAR SUPPORT AND RATIONALE IS USED FOR MJJ 2014, BUT SOUTHERN PORTIONS OF THE HIGHLIGHTED AREA ARE REMOVED AS THESE AREAS HAVE ENTERED THEIR CLIMATOLOGICAL DRY SEASON IN EARNEST.
BEYOND MJJ 2014, THE UNCERTAINTY OF PRECIPITATION GUIDANCE INCREASES AND FEW CLEAR SIGNALS ARE INDICATED, ALTHOUGH INCREASING CHANCES FOR EL NINO HAVE RESULTED IN SOME ADJUSTMENTS AT LONGER LEADS PRIMARILY BASED ON EL NINO COMPOSITES. ELEVATED CHANCES FOR BELOW-MEDIAN PRECIPITATION IS HIGHLIGHTED FOR PARTS OF THE WESTERN GULF COAST FROM JJA THROUGH ASO 2014 (ALSO SUPPORTED BY THE NMME AND IMME) AS WELL AS THE REMOVAL OF THE DRY SIGNAL ACROSS PARTS OF THE SOUTHEAST CONUS DURING NDJ, DJF AND JFM SEASONS. EL NINO CONDITIONS FAVOR ABOVE-MEDIAN PRECIPITATION DURING THESE SEASONS AND AREAS. IF PROSPECTS FOR EL NINO CONTINUE TO INCREASE, ABOVE-MEDIAN PRECIPITATION MAY BEGIN TO BE NOTED ON SUBSEQUENT OUTLOOKS.”