Tag: Rain

Seasonal Weather Ahead, Rain Possible At Week’s End

Brad Leave a comment

Benign weather will continue over the Red River Valley for the next few days as a weak ridge of high pressure remains entrenched over the region until Friday. Heading into the weekend, however, it looks like rain may be possible as a low pressure system moves into the region through the day.

There isn’t a whole lot to say regarding the coming days, so I’ll keep this post fairly brief! The weather for today and tomorrow will be largely dictated by a weak ridge of high pressure over the region that’s more a result of larger low pressure systems to our west and east than being particularly potent in and of itself.

Today will see temperatures climb to around 23°C with breezy winds building out of the north to 30–40km/h thanks to a low pressure system passing to our east. The day will start overcast with some mid- to high-level cloud that will gradually clear out through the day. Winds will taper off this evening as low temperatures head to around 9°C.

Thursday will be mainly sunny day with light winds and a high near 25°C. Expect a low near 13°C on Thursday night.

GDPS 12hr. QPF valid through Friday Night
The GDPS is showing a low pressure system moving through Southern Manitboa on Friday night capable of bringing some rain to the Red River Valley.

Friday will see increasing cloudiness, particularly in the afternoon as a low pressure system begins working into the region. Temperatures will climb to around 25°C. Friday night will likely bring some rain, although specifics are still quite fuzzy. Temperatures will dip back down to around 13°C again.

Mixed Weekend

This weekend looks mixed at this point, with slightly cooler, cloudier weather on Saturday with a chance of showers and sunnier conditions on Sunday. There’s quite a bit of uncertainty with Friday night/Saturday’s low pressure system, so it’s a bit early to make much in the way of concrete forecasts. High temperatures will likely be in the low 20’s with a chance of warmer weather returning for the beginning of next week.

Typhoon Nangka Wreaks Havoc on One of Japan’s Main Islands

Matthieu Leave a comment

This past week a typhoon made landfall on one of Japan’s islands, the island of Shikoku and with it brought winds the equivalent of a category one hurricane gusting up to 185km/h.

[map type=”terrain” autofit=”1″ disable_scrollwheel=”1″] [pin]Island of Shikoku[/pin] [pin]Kamikitayama, Japan[/pin] [/map]

 

Nangka initially formed in the middle of the Western Pacific Ocean about over a week ago and slowly strengthened as it approached Japan; it traveled over 5000km to make landfall. Over open waters it peaked at the equivalent of a category four hurricane, with sustained winds of over 200km/h and gained super typhoon status. Slightly cooler ocean waters (of 26°C to 27°C) towards Japan weakened the typhoon somewhat before it made landfall, but with that said, the typhoon’s impacts were still fairly significant. In expectation of the typhoon 550,000 residents were either issued a mandatory evacuation notice or voluntary evacuation notice, in the most prone-to, low-lying areas near the coast.

Beautiful satellite image of Nangka earlier this week while it was still over open waters. (Source: NWS OPC)
Beautiful satellite image of Nangka earlier this week while it was still over open waters. (Source: NWS OPC)

In total, two people perished from the typhoon and about three dozen people sustained injuries – thankfully it wasn’t worse due to good planning by authorities to get the people most at risk out. Numerous rail runs and flights were cancelled, affecting about 200,000 people’s daily activities. Some flooding did occur as the typhoon brought a plume of tropical moisture to the region with it, which led to rainfalls in excess of 700mm in the hardest hit areas in 48 hours (740mm reported in Kamikitayama). Just over 100 houses were reported to have been completely flooded out

Since Nangka has made landfall it has progressed to its dissipating stage, and possibly extratropical transition by the end of the weekend. However, it will still bring with it the threat of heavy rainfall in the northern Japanese islands and mountainous areas even though it continues to weaken. On average there are 16 typhoons in the Western Pacific in a year, and this year’s count is currently at seven. Most storms form in the Western Pacific between May and November (because shear is weaker) but there are occasional storms that form in the other months of the year.

Unsettled Weather Continues To Week’s End

Brad Leave a comment

The unsettled weather that’s been in place for the last few days will continue through the end of the week as the general instability remains in place as more weather systems push through the region.

Today will be a fairly pleasant day that’s quite similar to yesterday other than a couple degrees warmer. Temperatures should climb to around 28°C this afternoon with more clouds popping up and developing into an afternoon/evening chance of some scattered thunderstorms. Thunderstorm activity should be fairly limited as the main story will be the low pressure system that will move into Southern Manitoba overnight and will set the stage for Thursday’s weather. Expect temperatures to dip to just 19°C as increasing cloud and the humidity continue to keep temperatures warm.

Thursday Brings Heavy Rain Potential

Tomorrow may actually end up being quite a wet day as multiple models are showing a low pressure system moving through tapping into the ample moisture in the region to produce a fairly large, and intense, area of rain.

NAM Precipitable Water Forecast for 15Z Thursday July 16, 2015
NAM Precipitable Water Forecast for 15Z Thursday July 16, 2015

The NAM (shown above) is forecasting precipitable water values as high as 1.8 to 1.9” (in the 45–50mm range) which is very high for our region. Precipitable water correlates strongly to potential rainfall amounts of storm systems[1], so it’s not unrealistic to say that rainfall totals of 1.5” to 2” (~ 35 – 50mm) are not out of the question albeit on the high end. If heavy convection were to set up, then even higher amounts would be possible. We’ll keep an eye on things and see how the storm progresses this evening; if the outlook changes much, we’ll provide an update at the bottom of this post.

So, the general forecast for Thursday would see the rain moving in overnight on Wednesday night and see the rain persisting at least until mid-day, but possibly into the late afternoon or early evening. Rainfall totals may end up being variable, but in general will likely be 20–40mm with the potential of seeing double that if system becomes vigorous enough. The high temperature will be in the 21 to 23°C range with an overnight low around 16°C. Winds will be fairly light much of the day.

Friday

The thunderstorm risk returns Friday, although it will be a fairly mild risk with just some isolated to scattered non-severe storms possible. The daytime high will sit near 26 or 27°C with light winds out of the southwest. The humidity continues to remain fairly high with dew points in the high teens. Skies will clear out Friday night as we head to a low near 15°C.

  1. Thunderstorm rainfall totals can greatly exceed PWAT values due to the convergence of the inflow wind that can “accumulate” PWAT from areas around the storm.  ↩

Unsettled Start to the Week

Scott Leave a comment

The first part of this week will see unsettled weather as a strong low pressure system passes to our south. This system will likely result in moderate rainfall and a risk of thunderstorms over southern Manitoba on Tuesday.

Monday

Today looks to be mainly cloudy ahead of an approaching low pressure system. There may be a few passing showers throughout the day, but no major precipitation is expected. High temperatures are expected to reach the low twenties with gusty south winds.

Tuesday

Tuesday looks quite unsettled as we sit north of a fairly strong low pressure system over the Dakotas. A warm front will likely be located over northern North Dakota, allowing for warm and potentially stormy weather just to our south. In southern Manitoba, we will remain stuck in a cool easterly flow north of the warm front. As a result of our position relative to the warm front we likely see moderate rainfall during the day with a chance of embedded thunderstorms.

NAM Simulated RADAR Reflectivity
The simulated RADAR reflectivity from the NAM forecast for Tuesday afternoon shows a large area of rainfall moving over Southern Manitoba.

Should the warm front move further north than expected, our risk of thunderstorms will be higher, but at this time that does not look probable. Total rainfall amounts in southern Manitoba could be in the 15-35 mm range, although it is difficult to predict this sort of system ahead of time. Higher rainfall amounts are certainly possible on a localized basis due to isolated thunderstorm activity.

Wednesday

Wednesday looks cool and cloudy as Tuesday’s system departs. We my see a few showers during the day, but in general not much precipitation is expected. The wind will be from the north at around 30 km/h.

Long Range

The long range forecast suggests we’ll see generally normal to above-normal weather through the middle of June. Numerous weak to moderate weather systems are expected to traverse the region over the next while, meaning our weather will continue to feature unsettled patches, before we return to more favourable conditions.