Marine Weather and Tide Forecast for Nunn, CO

UPDATE
Issued at 315 AM MDT Mon May 12 2025

Only thing to consider for this aftn would be some dry microburst activity as soundings have an inverted-V type structure with decent DCAPE. Otherwise temps will be even warmer today with readings in the mid 80's to lower 90's across nern CO.

DISCUSSION /Through Sunday/
Issued at 206 PM MDT Sun May 11 2025

This afternoon's satellite imagery shows cumulus clouds stretching across the higher elevations. Like yesterday, the Day Cloud Phase channel shows a few of the cumulus starting to show signs of glaciation wanting to take hold over the central mountains and foothills, with some weak storms already forming over the Palmer Divide. With forecast soundings showing a near inverted-v profile, and SBCAPE values increasing to around 800 J/kg over the higher elevations, we anticipate some of the aforementioned cumulus growing enough to produce some scattered hi-based showers and weak storms this afternoon. The main impacts would be gusty outflows as the dry low-levels support sufficient downward motion from evaporative cooling represented in DCAPE values of around 900 J/kg in forecast soundings. A few of these may push of the mountains and onto the plains, but with MLCAPE values remaining below 300 J/kg, storms will weaken as they enter a less conducive environment. Gusty outflows around 35-45 mph will be the most likely impact as these pass.

Warm and dry conditions are still on track to persist into the start of the week as a lingering vertically stacked low over the Gulf states keeps Colorado under upper-level ridging for another day, despite an upper-level trough pushing ashore the Pacific Northwest on Monday.

700 mb temperatures will warm a few degrees on Monday, ranging from 11C - 15C across the forecast area. This will result in afternoon high temperatures at the surface also warming a few degrees from Sunday, bringing widespread upper 80s to the lower elevations, with portions of the South Platte River valley expected to hit the 90 degree mark. The foothills and mountain valleys will remain mild, with high temperatures in the 70s. With moisture lacking under the subsidence aloft, we should see some increased snowmelt over the mountains and our current moist fuels will have ample time to begin drying. With the persistent warmth and dryness, developing fire weather conditions will be our main concern for the week, and fuel conditions will need to be monitored. Over the weekend, there has been a noticeable drying trend in the 10-hr fuels, especially across the northeastern portion of the state, and into the mountain valleys. Tuesday and Wednesday look to be the days with the highest fire weather concerns at this time, and will continue to be monitored, but with the majority of our fuels remaining below critical status, critical fire weather concerns look to be patchy, and dependent on how drying trends continue over the next few days.

The synoptic pattern will shift as the aforementioned low over the Gulf states will begin to eject to the northeast on Tuesday, allowing for the Pacific Northwest trough to push eastward.
Height falls will begin across Colorado on Wednesday as the approaching trough axis to the west passes through the Great Basin, and we will see increasing southwesterly flow throughout the day. The main impacts still look to remain to the north, but we should see moisture increase along the northern tier of the forecast area, and between a cold front passage around Wednesday and increasing PVA, we should see some increasing chances for thunderstorms across the northern portion of the forecast area, and even some snow return to the northern mountains.

Temperatures will moderate towards normal behind the cold front, remaining near normal through the end of the week, but there is still plenty of time for things to change between now and then.

AVIATION /12Z TAFS through 12Z Tuesday/
Issued at 506 AM MDT Mon May 12 2025

Winds were SW early this morning and will become more light and variable by 16z. For this aftn not sure about overall directions as winds will stay rather light. Eventually winds will become SE by 23z 00Z and then trend to more SSW by 06z tonight. There is still a 10% chance of a few dry microbursts this aftn by 21z with brief gusty winds possible through 01Z.

BOU WATCHES/WARNINGS/ADVISORIES
None.