Pleasant Second Half of the Week

Brad Leave a comment

After some unsettled weather the past couple days, we’ll be seeing pleasant, slightly warmer-than-normal days through the second half of the week as a ridge of high pressure builds into the Prairies.

Wednesday

22°C / 8°C
A few clouds and breezy. Slight chance of isolated late-day showers.
Thursday

21°C / 7°C
Mainly sunny.
Friday

24°C / 12°C
Mainly sunny.

We’ll see a few clouds today with a breezy northerly wind as cooler air moves in behind yesterday’s cold front. We may see some isolated showers late in the day thanks to weak convergence along the western shores of Lake Winnipeg, however they would certainly not be widespread and they would have very limited duration. We’ll see a high of around 22°C tomorrow and we’ll drop down to a chilly 8°C overnight under clear skies.

Thursday will be the coolest day of the week with temperatures topping out only around 21°C and an overnight low dropping down to around 7°C. It may actually end up being one or two degrees colder than that at night depending exactly where the main axis of the surface ridge lines up, but suffice to say it will be quite cool on Thursday night. Winds will be light through the day and we’ll see mainly sunny skies and a clear night.

Outgoing Longwave Flux for 00Z Saturday Sept. 14, 2013 -- approximates cloud cover -- showing a potent low pressure system pushing through the Kivalliq region of Nunavut.

Outgoing Longwave Flux for 00Z Saturday Sept. 14, 2013 – approximates cloud cover – showing a potent low pressure system pushing through the Kivalliq region of Nunavut.

Friday looks to be a fairly nice day as an incredibly potent low pressure system moving through the Kivalliq region of Nunavut into Hudson Bay draws warm air from the Alberta Foothills eastwards across the Prairies. At this point it looks like Winnipeg will get into that warm air and see a high temperature around 25°C, although if the warmth ends up occluding slightly faster, the mid–20’s may be confined to Montana and North Dakota while we remain in the low 20’s. We’ll see a few clouds through the day, but for the most part it should be quite nice with winds out of the south or southwest at around 20km/h. Friday night will cool off to the low teens under clear skies.

A Look Ahead to the Weekend

The weekend looks pretty great at this point. A large ridge of high pressure will move in behind the powerful Arctic low bringing sunny skies, light winds and highs in the low 20’s. Saturday & Sunday nights will be quite chilly, though, with temperatures dipping down into the 4–5°C range, and perhaps even cooler outside the City of Winnipeg. We may end up seeing our first significant risk of frost this weekend depending on exactly how strong that ridge of high pressure ends up being.

An Oasis on the Horizon?

Brad Leave a comment

After weeks of dry weather, some rain is finally on the way. However, for those desperately wanting rain, the water works may only come after the rain has ended.

A Low Pressure System will Spread Rain Over the Northern Plains on Monday

Monday

Monday

Mainly cloudy. Chance of showers.
23°C / 14°C

Today will see rain over some parts of Southern Manitoba as a powerful upper low approaches the region. This system will tap significant moisture over the Northern Plains, generating an area of moderate to heavy rainfall over the Dakotas. The core of this rain will slide mainly south through North Dakota and Minnesota, however the northern fringe of it may clip areas along the International Border up into south-eastern Manitoba. In these border regions rainfall amounts will be very hard to predict in advance, but a reasonable estimate would be for 5 to 15mm for the entire day. Actual amounts could be slightly higher or lower than this depending on the track of the system. In the rest of Southern Manitoba, little to no rain is expected. There will be a constant threat of showers today and tonight, but most areas including Winnipeg, should see very little if any rain. Other than the rain it will be a cloudy, but mild day, with light winds.

Tuesday and Wednesday

Tuesday

Mix of Sun and Cloud. Chance of Showers or Thundershowers.
27°C / 10°C
Wednesday

Mainly Sunny
21°C / 6°C

Tuesday should be a fairly nice day in Southern Manitoba. Skies will be a mixture of sun and cloud with temperatures in the mid to upper twenties. Late in the day a cold front will come through, likely triggering some showers and thunderstorms. These storms are not expected to be severe.

Not surprisingly, Wednesday will be a cooler day as colder air moves in behind that cold front. High temperatures will be in the low twenties with gusty north-westerly winds. Some fair weather cumulus clouds may develop during the day, but otherwise it will be mainly sunny.

Long Range

The long range outlook is a bit ambiguous at this point. It appears that we’ll probably see conditions begin to warm up around the weekend, only to be knocked back down by another cold front later on the weekend or into next week. This sort of up and down pattern makes forecasting fairly tough, so rather than making any sort of grand prediction I’ll just suggest that we’re in for a variable pattern with some warm weather interspersed with cooler periods.

Elsewhere in Weather News: September 7th, 2013

Matthieu Leave a comment

Tropical Storm Gabrielle Drenches Parts of Caribbean

The seventh storm of the Atlantic hurricane season spun up this past week, though did not affect the continental United States. The tropical storm, Gabrielle, did not reach hurricane status due to unfavorable conditions for storm development, including shear levels being on the high side. Shortly after it made landfall on Thursday it had been downgraded to tropical depression status. Drenching rains still fell across Puerto Rico, Dominican Republic and the US Virgin Islands thanks to Gabrielle’s southerly flow bringing in copious amounts of moisture (PWAT values approaching 75mm) from the Caribbean Sea.

Gabrielle

Gabrielle shortly after it got downgraded to a tropical depression on Thursday early afternoon. (Source: WUnderground)

As of Friday morning the highest rainfall amounts came out of St. Thomas where 175mm had already fallen. In general anywhere between 100mm to 250mm will have fallen across the region after Gabrielle has moved off to the north in the middle of the Atlantic Ocean. Friday evening the storm had been almost completely torn apart north of Puerto Rico and wasn’t a threat to land anymore. No deaths or injuries have been reported with the storm.

Surprisingly there has not been one hurricane in the Atlantic so far this year and if there continues to be a lack of hurricanes until September 16th, a record for the latest start to a hurricane season (since records began) would be achieved. However, longer range models such as the GFS have been showing tropical development in the Caribbean as well as another wave coming off Africa’s west coast in the near future which will be something to keep an eye on.

Fantastic Weekend In Store

Brad Leave a comment

We’ll see a beautiful weekend ahead of us as an upper ridge holds strong bringing sunny skies and warm temperatures to the Red River Valley.

Friday

30°C / 15°C
Chance of morning showers, then mainly sunny & a little humid.
Saturday

27°C / 12°C
Cloudy periods.
Sunday

23°C / 15°C
Increasing cloudiness through the day.

We’ll start today off with some cloud around and a chance of some shower activity in the Winnipeg area along a weak warm front, but that should clear out fairly quickly and we’ll be left with mainly sunny skies as we climb to a high of around 30°C. The humidity will become a little noticeable by the afternoon as a strong capping inversion in place will trap moisture given off by plants near the surface; as a result it will feel a little more sticky than it has as of late, but it shouldn’t be uncomfortable. The warmest air will slump southwards into North Dakota tonight as we drop down to a low of around 15°C with light northerly winds kicking in.

Saturday will bring a few cloudy periods as we climb to a high of around 27°C. Temperatures will drop to the low teens on Saturday night under clear skies.

Things will begin to deteriorate on Sunday with cloud cover pushing in through the day as we hit a high of 23°C or so. Sunday night looks cloudy with a chance of showers or thunderstorms reaching the Red River Valley by early Monday morning. The low will be around 15°C.

Next Week

Forecast precipitation for Sunday night to Monday evening from the GDPS.

Forecast precipitation for Sunday night to Monday evening from the GDPS.

Monday looks to be the most active day next week as a low pressure system lifts out of South Dakota northeastwards into the Lake of the Wood region. This system will be tapping into moist air to it’s south and lifting it northwards and around the backside of the low which, if things go as planned, will result in one of the most widespread rainfalls we’ve seen in a while. Some models are moving towards a more convective solution, though, where a narrow but intense band of thunderstorms will cut a swath through somewhere in the Red River Valley. We’ll have to wait and see, but at this point it certainly looks like Monday will be at least a cloudy, if not rainy, day with temperatures in the low 20’s.

The rest of the week will see some sun and some cloud with temperatures returning to above-normal values in the mid–20’s. A few weak disturbances may create a bout or two of scattered showers or thunderstorms through the week, but at this point nothing significant is in the picture.