000 FXUS01 KWBC 072054 PMDSPD SHORT RANGE FORECAST DISCUSSION NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD 454 PM EDT TUE OCT 07 2008 VALID 00Z WED OCT 08 2008 - 12Z THU OCT 09 2008 THE WEATHER PATTERN WILL BE ACTIVE EAST OF THE MISSISSIPPI RIVER AS AN UPPER-LEVEL TROUGH MOVES THROUGH THE MISSISSIPPI VALLEY THIS EVENING. A STEADY FLOW OF MOISTURE IN ADVANCE OF THE FRONTAL BOUNDARY HAS ALLOWED NUMEROUS SHOWERS AND THUNDERSTORM TO FIRE ACROSS THE LOWER AND MIDDLE MISSISSIPPI VALLEYS TODAY. WHILE THIS FRONT WILL NOT CAUSE A DISCERNIBLE CHANGE IN TEMPERATURE...IT WILL BRING WET CONDITIONS TO MANY REGIONS OF THE CENTRAL GULF COAST...TENNESSEE VALLEY...AND OHIO VALLEY ON WEDNESDAY. HOWEVER...THE BEST CHANCE FOR HEAVIER PRECIPITATION WILL BE ALONG THE GULF COAST AS A BULK OF THE ENERGY ALOFT WITH MOVE EASTWARD WITH THE SOUTHERN BRANCH OF THE JET STREAM. ACROSS THE NORTHWESTERN TIER...A SERIES OF WAVES OF ENERGY WILL MOVE THROUGH SOUTHWESTERN CANADA THROUGHOUT THE DAY AND EVENTUALLY DIP DOWN INTO THE NORTHERN PLAINS BY WEDNESDAY AFTERNOON. WHILE A BULK OF THE DISTURBED WEATHER WILL REMAIN ACROSS BRITISH COLUMBIA AND ALBERTA...SOME PRECIPITATION SHOULD FALL ACROSS THE FAVORED TERRAIN OF THE PACIFIC NORTHWEST. ACROSS THE HIGHEST ELEVATIONS...COOL ENOUGH TEMPERATURES WILL BE SUPPORTIVE OF A DUSTING OF SNOW. THE WEATHER ACROSS THE PACIFIC NORTHWEST ALONG WITH MUCH OF THE UPPER AND CENTRAL INTERMOUNTAIN WEST WILL BE COOL AND MOSTLY CLOUDY AS A LARGE UPPER-LEVEL TROUGH REMAINS OVERHEAD. AS THE PREVIOUSLY MENTIONED DISTURBANCES MOVE TOWARD MANITOBA AND THE UPPER MIDWEST...A MORE SIGNIFICANT SURGE OF COLD AIR WILL DIVE SOUTHEASTWARD FROM THE GULF OF ALASKA AND SLAM INTO THE U.S. COASTLINE. IN ADVANCE OF THIS PACIFIC SYSTEM...WINDS WILL SIGNIFICANTLY PICK UP ALONG THE PACIFIC NORTHWEST COAST REACHING GUSTS UP TO 30 TO 35 MPH BY MIDDAY THURSDAY. IN ADDITION...THE ENHANCED ONSHORE FLOW WILL HELP SPAWN NUMEROUS SHOWERS ACROSS WESTERN WASHINGTON. A RIDGE OVER THE DESERT SOUTHWEST WILL HOLD STRONG ANOTHER COUPLE OF DAYS BEFORE BREAKING DOWN AS THE STRENGTHENING TROUGH OVER THE EASTERN PACIFIC MOVES INTO THE REGION. THE AREA OF HIGH PRESSURE WILL PROMOTE DAYTIME TEMPERATURES APPROACHING THE CENTURY MARK WITH WIDESPREAD 90S ACROSS THE VALLEYS AND DESERTS. BY THE END OF THE WORK WEEK...A CHANGE IN THE WEATHER PATTERN WILL BRING A CLOSE TO THE ABUNDANT WARMTH. OVER THE NORTHEASTERN U.S...A DOME OF SURFACE HIGH PRESSURE EXITING THE EASTERN SEABOARD WILL BRING ONE MORE COLD NIGHT TO THE REGION. UNDERNEATH THIS RIDGE...CLEARING SKIES ACCOMPANIED BY CALM WINDS WILL PROMOTE EXTENSIVE COOLING TUESDAY NIGHT WHICH HAS CAUSED NUMEROUS FREEZING WARNINGS AND FROST ADVISORIES TO BE PUT INTO EFFECT. TEMPERATURES OVERNIGHT WILL APPROACH THE LOW TO MID 30S WHILE THE METROPOLITAN CITIES SHOULD REMAIN ABOVE 40 DEGREES. RUBIN-OSTER GRAPHICS AVAILABLE AT WWW.HPC.NCEP.NOAA.GOV $$