Upcoming pattern change signals trend to warmer drier weather for the Prairies

Our cool and wet September is drawing to a close, but it looks like some warmer and drier weather will finally be moving in for the last few days of the month. A persistent storm track over the northern US has brought several significant rainfall events over southern Manitoba over the past 4 weeks, with 100-250 mm of rain across the Red River valley during that time. The suppressed jet stream has also maintained cooler than normal temperatures through the period with only 2 days reaching the 20C mark in Winnipeg this month. But a long awaited pattern change is finally beginning this weekend, and long range models are suggesting drier and warmer than normal conditions will persist across the Prairies through the first week of October. (see 6-10 day outlook from CPC)

In the short term, early morning cloud and fog patches will give way to sunshine and pleasant temperatures today, with afternoon highs in the mid to upper teens along with light winds. Even warmer conditions are expected Sunday as gusty south winds to 60 km/h push temperatures into the low to mid 20s across southern MB, possibly the warmest day of the month so far. A weak cold front will pass through Monday with a slight chance of showers, followed by sunny skies and 20C temperatures Tuesday. Dry but slightly cooler weather is expected for the end of the week as high pressure builds over the eastern Prairies. Long range models continue to indicate the development of a large upper ridge over the Prairies during the first week of October, bringing a spell of warm and dry weather to southern Manitoba to start the new month. Here's hoping to warmer and drier weather in October!

Another soaking rain for the Red River valley

Southern Manitoba once again received more rain Thursday night on already saturated grounds. A storm system moving through the Dakotas brought rainfall amounts of 20 to 50 mm over the Red River Valley Thursday through Thursday night with over 60 mm falling over extreme southeastern Manitoba.

Here is a summary of some of the more significant rainfall amounts reported over the last 24 hours as of 8 AM Friday morning.

Winnipeg (airport) .. 19.0 mm
Winnipeg (Forks) .... 17.6 mm
Winnipeg (St. Vital)... 25.4 mm
Winnipeg (Chwd) ...... 22.6 mm /Rob's Obs/
Dugald .............. 36.4 mm
Letellier ........... 37.0 mm
St. Pierre .......... 50.4 mm
Morris .............. 48.2 mm
Steinbach ........... 38.8 mm
Gretna .............. 27.8 mm
Emerson ............. 38.0 mm
Starbuck ............ 20.4 mm
Winkler ............. 33.6 mm
Vassar .............. 51.5 mm
Piney ............... 55.4 mm
Sprague ............. 63.0 mm

24C by Sunday? Could it be?

Long range models continue to indicate an upcoming change this weekend in the below normal weather pattern that has plagued the Prairies most of September. A large upper ridge is forecast to build over western North America by the weekend that will send a surge of warm air across Alberta and Saskatchewan beginning Saturday. Low pressure crossing the northern Prairies will push this warmth eastward over southern Manitoba on Sunday with temperatures expected to climb into the low to mid 20s.. potentially the warmest day of the month so far that has seen only 2 days reach the 20C mark in Winnipeg, with a maximum of only 22C on the 1st. Current forecasts suggest 24C temperatures continuing Monday in Winnipeg however, model guidance is indicating a brief cooldown Monday and Tuesday before another surge of warm air moves in for the middle and end of next week. All in all, it looks like we may finally be seeing some above normal temperatures to end what has been a generally cool September.

2010 growing season ends for Winnipeg and northern RRV

A ridge of high pressure brought clear skies and light winds last night to Winnipeg and the northern Red River valley, allowing widespread frost to form early this morning. Temperatures dipped to a low of -1.5C at Winnipeg airport, officially ending the 2010 growing season for the city. Using airport data, this year's growing season was 132 days , 11 days longer than average, and 18 days longer than 2009. This was due to a fairly early start to the growing season this year with the last spring frost recorded on May 9th at the airport.. some 2 weeks ahead of the normal last frost. At Winnipeg airport, the average growing season is about 121 days between an average last spring frost on May 23rd, and a first fall frost on Sept 22nd. Last year, the airport had a 114 day growing season (Jun 7th - Sept 28th), shortened due to a late spring frost in June.

Elsewhere across the Red River valley, most areas north of Highway 3 had frost this morning with overnight lows of 0 to -2C. The southern valley however escaped frost due to cloud cover that spread along the US border. Areas from Morris southward generally stayed above freezing last night.

Increasing cloud cover and moderating temperatures will prevent the threat of frost over the next few days. In fact, long range models are hinting of above normal temperatures moving in for next weekend into the last week of September with temperatures of 20-25C possible. Here's hoping!

Frost likely tonight across Red River valley

Winnipeg and the Red River valley were spared from frost last night due to a steady westerly wind that kept temperatures above zero. Tonight however, winds are expected to be light as a ridge of high pressure builds into southern MB. That ridge brought a hard freeze to much of southern SK and Alberta last night with overnight lows of -2 to -7C. Clear skies and light winds in the ridge allowed for maximum radiational heat loss from the surface, resulting in the frosty temperatures. Overnight lows aren't expected to be quite as cold tonight over southern MB as temperatures moderate somewhat today and some high level cloud moves in tonight, however widespread readings of 0 to -2C are likely by early Sunday morning across the Red River valley including Winnipeg (except downtown which should remain above zero due to the urban heat island effect). The southern Red River valley may also be spared from frost with some thicker cloud cover spreading in from Montana. Overall though it looks like the growing season will officially come to an end Sunday morning in Winnipeg, a good 10 days earlier than last year (first frost last year at Winnipeg airport was on September 29th with a minimum of -2.4C during the city's warmest September on record)