Valid Friday, June 21, 2013 to Tuesday, July 02, 2013

Summary of Forecasts and Hazards

US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JUNE 18 2013

SYNOPSIS: EARLY IN THE PERIOD A SERIES OF SURFACE LOWS ARE PREDICTED TO DEVELOP OVER THE CENTRAL PLAINS ALONG A FRONTAL SYSTEM EARLY IN THE PERIOD AND TRACK NORTHEASTWARD TOWARDS THE UPPER MISSISSIPPI VALLEY, BRINGING WET WEATHER TO SOME OF THESE AREAS. AN ASSOCIATED STATIONARY FRONT IS EXPECTED TO EXTEND EASTWARD FROM THE UPPER MISSISSIPPI VALLEY INTO THE NORTHEAST, BRINGING RAIN TO PARTS OF THESE REGIONS. DOWNSTREAM, A STATIONARY FRONT IS ANTICIPATED TO DEVELOP ACROSS THE SOUTHEAST COAST, WHICH MAY BRING RAIN TO PARTS OF THIS AREA. SURFACE HIGH PRESSURE IS ANTICIPATED TO BUILD ACROSS MANY PARTS OF THE LOWER 48 STATES EXCLUDING THE AFOREMENTIONED AREAS.

HAZARDS

• HEAVY RAIN FOR PARTS OF THE UPPER MISSISSIPPI VALLEY AND NORTHERN PLAINS, FRI-SAT, JUN 21-22.
• HEAVY RAIN FOR PARTS OF THE PACIFIC NORTHWEST, SUN-MON, JUN 23-24.
• MUCH ABOVE NORMAL TEMPERATURES FOR MUCH OF ALASKA, FRI-SAT, JUN 21-22.
• FLOODING ACROSS PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY, NORTH DAKOTA, GEORGIA, AND TEXAS.
• SEVERE DROUGHT FOR PARTS OF THE GREAT PLAINS, RIO GRANDE VALLEY, ROCKIES, SOUTHWEST, GREAT BASIN, CALIFORNIA, AND HAWAII.

DETAILED SUMMARY

FOR FRIDAY JUNE 21 - TUESDAY JUNE 25: A SERIES OF SURFACE LOWS ARE FORECAST TO TRACK FROM THE CENTRAL PLAINS TO THE UPPER MISSISSIPPI VALLEY DURING THIS PERIOD, BRINGING HEAVY RAIN TO PARTS OF THE UPPER MISSISSIPPI VALLEY AND NORTHERN PLAINS FRIDAY TO SATURDAY. SOME MODELS ARE INDICATING THE POSSIBILITY OF SOME AREAS RECEIVING OVER 2 INCHES OF RAIN IN A 24-HOUR PERIOD.

A SURFACE LOW PRESSURE SYSTEM IS PREDICTED TO APPROACH THE PACIFIC NORTHWEST COAST BY SUNDAY. STRONG ONSHORE FLOW ASSOCIATED WITH THIS STORM SYSTEM IS EXPECTED TO BRING HEAVY RAIN TO PARTS OF THE PACIFIC NORTHWEST SUNDAY TO MONDAY. SOME MODELS ARE INDICATING THE POTENTIAL FOR SOME AREAS TO RECEIVE 2 INCHES OF RAIN OR GREATER IN A 24-HOUR PERIOD.

AN AMPLIFIED UPPER-LEVEL RIDGE OVER ALASKA IS EXPECTED TO CONTINUE TO BRING MUCH ABOVE NORMAL TEMPERATURES FOR MUCH OF THE STATE FRIDAY TO SATURDAY, PREDOMINANTLY FOCUSED OVER MAINLAND ALASKA. SOME AREAS MAY SEE TEMPERATURES 20 DEGREES F OR GREATER ABOVE NORMAL.

A SURFACE LOW PRESSURE SYSTEM IS FORECAST TO ENTER THE ALEUTIANS BY SATURDAY, WHICH MAY BRING HIGH WINDS TO PARTS OF THE AREA. HOWEVER, SIGNIFICANT MODEL DIFFERENCES PRECLUDES THE DESIGNATION OF A HAZARD AREA AT THIS TIME. THE 06Z OPERATIONAL GFS INDICATES SUSTAINED WIND SPEEDS OF 30 KNOTS OR GREATER FOR PARTS OF THE ALEUTIANS, WHEREAS THE THE 00Z OPERATIONAL ECMWF KEEPS WIND SPEEDS AT ABOUT 20 KNOTS.

THE MIDDLE MISSISSIPPI VALLEY, NORTH DAKOTA, GEORGIA, AND TEXAS CONTINUE TO BE AREAS THAT ARE THE FOCUS FOR ONGOING RIVER FLOODING. SOME OF THESE REGIONS ARE EXPECTED TO SEE ADDITIONAL RAINFALL DURING THIS PERIOD WHICH COULD AGGRAVATE AND EXPAND THE FLOODING AREAS.

FOR WEDNESDAY JUNE 26 - TUESDAY JULY 02: THERE IS CURRENTLY A TROPICAL DEPRESSION LOCATED OVER THE YUCATAN PENINSULA WHICH NHC EXPECTS TO TRACK ACROSS THE BAY OF CAMPECHE OVER THE NEXT TWO DAYS. THIS STORM IS NOT EXPECTED TO HAVE ANY DIRECT IMPACTS TO THE CONUS AT THIS TIME, BUT MAY SUPPLY MOISTURE NORTHWARD INTO MEXICO AND TEXAS, WHICH MAY ENHANCE PRECIPITATION ACROSS TEXAS AND THE SOUTHWEST AROUND THE TIME OF THE ONSET OF THE NORTH AMERICAN MONSOON.

THE MJO IS FORECAST TO STRENGTHEN AND BECOME MORE COHERENT ACROSS THE MARITIME CONTINENT AND PACIFIC IN COMING WEEKS, WHICH MAY ENHANCE RAINFALL IN THE SOUTHWEST ASSOCIATED WITH THE NORTH AMERICAN MONSOON.

IN GENERAL, AN UPPER-LEVEL RIDGE IS PREDICTED TO BUILD ACROSS THE WEST-CENTRAL CONUS AND ALASKA DURING THIS PERIOD, BRINGING ABOVE-NORMAL TEMPERATURES TO MANY PARTS OF THE NORTHERN HALF AND WESTERN CONUS, AND ALASKA. AN UPPER-LEVEL TROUGH IS ANTICIPATED TO DEVELOP OVER THE EASTERN THIRD OF THE CONUS, BRINGING ABOVE-MEDIAN PRECIPITATION TO THE AREA. BELOW-MEDIAN PRECIPITATION IS EXPECTED FOR MOST OF ALASKA, EXCLUDING THE ALASKAN PANHANDLE, AND PARTS OF THE WESTERN CONUS ASSOCIATED WITH UPPER-LEVEL RIDGING IN THAT AREA.

FORECASTER: MELISSA OU

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