Climatological Report (Monthly)
Issued by NWS Boise, ID
Issued by NWS Boise, ID
029 CXUS55 KBOI 011758 AAA CLMBOI CLIMATE REPORT...CORRECTED TO ADD NARRATIVE NATIONAL WEATHER SERVICE BOISE ID 1035 AM MST FRI DEC 01 2023 NOVEMBER 2023 THE TEMPERATURE AVERAGED 2.6 DEGREES ABOVE NORMAL. IT WAS THE SEVENTH CONSECUTIVE WARMER-THAN-NORMAL MONTH. PRECIPITATION WAS ONLY .01 INCH ABOVE NORMAL. SNOWFALL INCLUDED A TRACE ON THE 6TH AND 0.1 INCH ON THE 30TH. THE 30-YEAR AVERAGE (1991- 2020) FOR NOVEMBER IS 2 INCHES. THERE WERE NO RECORD TEMPERATURES OR PRECIPITATION AMOUNTS. DISTURBANCES EMBEDDED IN MOIST WESTERLY FLOW ALOFT BROUGHT DAILY PRECIPITATION FROM THE 2ND THROUGH THE 6TH. DRY WEATHER PREVAILED FROM THE 7TH THROUGH THE 17TH. PACIFIC WEATHER SYSTEMS MOVED INLAND EITHER WELL NORTH OR WELL SOUTH OF OUR AREA FROM THE 7TH THROUGH THE 11TH. FROM THE 12TH THROUGH THE 15TH, WE WERE UNDER DRY SOUTHWEST FLOW ALOFT ON THE EAST FLANK OF A LOW PRESSURE TROUGH MOVING SOUTH FROM THE GULF OF ALASKA TO OFF THE CALIFORNIA COAST. BY THE 16TH, A "REX BLOCK" HAD FORMED, WITH A HIGH PRESSURE RIDGE OVER THE PACIFIC NORTHWEST, DIRECTLY NORTH OF THE CALIFORNIA TROUGH. FINALLY, ON THE 18TH, A TROUGH FROM THE ALEUTIANS JOINED FORCED WITH THE CALIFORNIA TROUGH, AND BOTH MOVED INLAND. THE HALF INCH OF RAIN ON THE 19TH WAS THE HEAVIEST ONE-DAY PRECIPITATION OF THE MONTH. TEMPERATURES HAD BEEN ABOVE NORMAL FROM THE 10TH THROUGH THE 19TH. BUT NORTHERLY FLOW AT THE SURFACE AND ALOFT BEHIND A COLD FRONT KEPT TEMPERATURES NEAR NORMAL FROM THE 20TH THROUGH THE 24TH. ON THE 23RD AND 24TH, A TROUGH FROM WESTERN CANADA PLUNGED SOUTH OVER THE GREAT BASIN. NORTHEAST FLOW OVER THE NORTHERN ROCKIES ALLOWED COLD AIR TO TRICKLE OVER THE CONTINENTAL DIVIDE INTO CENTRAL AND EASTERN IDAHO. BY THE 25TH, SURFACE WINDS FROM THE SOUTHEAST HAD TRANSPORTED THE COLD AIR DOWN THE SNAKE RIVER VALLEY. THE TROUGH BROUGHT SNOW TO AREAS SOUTH AND EAST OF BOISE. SNOW- COVERED GROUND IN THE UPPER SNAKE RIVER VALLEY, THE MAGIC VALLEY, AND THE HIGH TERRAIN SOUTH OF THE VALLEY REINFORCED THE COLD AIR DURING THE LONG NIGHTTIME HOURS. MEANWHILE, A HIGH PRESSURE RIDGE OVER THE PACIFIC NORTHWEST BROUGHT WARMER AIR ALOFT, FORMING A TEMPERATURE INVERSION AS IT TRAPPED THE COLD AIR AT LOWER ELEVATIONS. FROM THE 25TH THROUGH THE END OF THE MONTH, BOISE`S TEMPERATURES AVERAGED 5-10 DEGREES BELOW NORMAL IN THE STAGNANT AIR UNDER THE INVERSION. ALTHOUGH NIGHTS WERE COLD, MOSTLY SUNNY SKIES ALLOWED AFTERNOON TEMPERATURES TO REACH THE UPPER 30S AND LOWER 40S. ON THE 30TH, STRONG WESTERLY FLOW ALOFT ACROSS THE NORTH PACIFIC CARRIED A WEATHER SYSTEM INLAND OVER OUR AREA. LIGHT SNOW BEGAN LATE IN THE EVENING AS MOIST AND RELATIVELY WARM AIR MOVED OVER THE COLD AIR IN THE VALLEY. ................................... ...THE BOISE ID CLIMATE SUMMARY FOR THE MONTH OF NOVEMBER 2023... CLIMATE NORMAL PERIOD 1991 TO 2020 CLIMATE RECORD PERIOD 1875 TO 2023 WEATHER OBSERVED NORMAL DEPART LAST YEAR`S VALUE DATE(S) VALUE FROM VALUE NORMAL .............................................................. TEMPERATURE (F) HIGHEST 67 11/15 LOWEST 19 11/25 11/27 11/29 AVG. MAXIMUM 52.1 48.8 3.3 AVG. MINIMUM 33.7 31.7 2.0 MEAN 42.9 40.3 2.6 DAYS MAX >= 90 0 DAYS MAX <= 32 0 DAYS MIN <= 32 13 DAYS MIN <= 0 0 PRECIPITATION (INCHES) RECORD MAXIMUM 4.43 1874 TOTALS 1.19 1.18 0.01 DAYS >= .01 9 DAYS >= .10 4 DAYS >= .50 1 DAYS >= 1.00 0 GREATEST 24 HR. TOTAL 0.52 11/18 TO 11/19 SNOWFALL (INCHES) TOTALS 0.1 SINCE 7/1 0.1 GREATEST SNOW DEPTH 0 24 HR TOTAL MM DEGREE DAYS HEATING TOTAL 657 742 -85 918 SINCE 7/1 987 1212 -225 COOLING TOTAL 0 0 0 0 SINCE 1/1 1342 1044 298 .............................................................. WIND (MPH) AVERAGE WIND SPEED 5.6 HIGHEST WIND SPEED/DIRECTION 32/310 DATE 11/19 HIGHEST GUST SPEED/DIRECTION 46/310 DATE 11/19 AVERAGE RH (PERCENT) 64 - INDICATES NEGATIVE NUMBERS. R INDICATES RECORD WAS SET OR TIED. MM INDICATES DATA IS MISSING. T INDICATES TRACE AMOUNT. $$